| 1. |
- Bhatti, Adeel Liaquat, et al.
(författare)
-
An Efficient and Functional Fe3O4/Co3O4 Composite for Oxygen Evolution Reaction
- 2021
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Ingår i: Journal of Nanoscience and Nanotechnology. - : AMER SCIENTIFIC PUBLISHERS. - 1533-4880 .- 1533-4899. ; 21:4, s. 2675-2680
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Tidskriftsartikel (refereegranskat)abstract
- The design of efficient, stable, durable and noble metal free electro catalysts for oxygen evolution reaction (OER) are of immediate need, but very challenging task. In this study, iron induction into cobalt oxide (Co3O4) has resulted composite structure by wet chemical method. The iron impurity has brought an electronic disorder into Fe3O4/cobalt oxide composite thereby efficient oxygen evolution reaction is demonstrated. An addition of iron content into composite resulted the alternation of morphology from Nano rods to clusters of nanoparticles. The successive addition of iron into composite system reduced the onset potential of OER as compared to the pristine cobalt oxide. A Tafel slope of 80 mVdec(-1) indicates the favorable oxygen evolution reaction kinetics on the sample 4. An over-potential of 370 mV is required to reach a 10 mAcm(-2) current density which is acceptable for a nonprecious catalyst. The catalyst is highly durable and stable for 30 hours. Electrochemical impedance spectroscopy further provided a deeper insight on charge transfer resistance and sample 4 has low charge transfer resistance that supported the OER polarization curves. The sample 4 has more electrochemical active surface area of 393.5 cm(2). These obtained results are exciting and highlighting the importance of composite structure and leave a huge space for the future investigations on composite materials for energy related applications.
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| 2. |
- Arslan, Muhammad, et al.
(författare)
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Impact of Varying Load Conditions and Cooling Energy Comparison of a Double-Inlet Pulse Tube Refrigerator
- 2020
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Ingår i: Processes. - : MDPI. - 2227-9717. ; 8:3
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Tidskriftsartikel (refereegranskat)abstract
- Modeling and optimization of a double-inlet pulse tube refrigerator (DIPTR) is very difficult due to its geometry and nature. The objective of this paper was to optimize-DIPTR through experiments with the cold heat exchanger (CHX) along the comparison of cooling load with experimental data using different boundary conditions. To predict its performance, a detailed two-dimensional DIPTR model was developed. A double-drop pulse pipe cooler was used for solving continuity, dynamic and power calculations. External conditions for applicable boundaries include sinusoidal pressure from an end of the tube from a user-defined function and constant temperature or limitations of thermal flux within the outer walls of exchanger walls under colder conditions. The results of the system's cooling behavior were reported, along with the connection between the mass flow rates, heat distribution along pulse tube and cold-end pressure, the cooler load's wall temp profile and cooler loads with varied boundary conditions i.e. opening of 20% double-inlet and 40-60% orifice valves, respectively. Different loading conditions of 1 and 5W were applied on the CHX. At 150 K temperature of the cold-end heat exchanger, a maximum load of 3.7 W was achieved. The results also reveal a strong correlation between computational fluid dynamics modeling results and experimental results of the DIPTR.
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| 3. |
- Bhatti, Adeel Liaquat, et al.
(författare)
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Facile doping of nickel into Co3O4 nanostructures to make them efficient for catalyzing the oxygen evolution reaction
- 2020
-
Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 10:22, s. 12962-12969
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Tidskriftsartikel (refereegranskat)abstract
- Designing a facile and low-cost methodology to fabricate earth-abundant catalysts is very much needed for a wide range of applications. Herein, a simple and straightforward approach was developed to tune the electronic properties of cobalt oxide nanostructures by doping them with nickel and then using them to catalyze the oxygen evolution reaction (OER) in an aqueous solution of 1.0 M KOH. The addition of a nickel impurity improved the conductivity of the cobalt oxide, and further increased its activity towards the OER. Analytical techniques such as scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and powder X-ray diffraction (XRD) were used to investigate, respectively, the morphology, composition and crystalline structure of the materials used. The nickel-doped cobalt oxide material showed randomly oriented nanowires and a high density of nanoparticles, exhibited the cubic phase, and contained cobalt, nickel and oxygen as its main elements. The nickel-doped cobalt oxide also yielded a Tafel slope of 82 mV dec(-1) and required an overpotential of 300 mV to reach a current density of 10 mA cm(-2). As an OER catalyst, it was shown to be durable for 40 h. Electrochemical impedance spectroscopy (EIS) analysis showed a low charge-transfer resistance of 177.5 ohms for the nickel-doped cobalt oxide, which provided a further example of its excellent OER performance. These results taken together indicated that nickel doping of cobalt oxide can be accomplished via a facile approach and that the product of this doping can be used for energy and environmental applications.
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| 4. |
- Hanan, Abdul, et al.
(författare)
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PdO@CoSe2 composites: efficient electrocatalysts for water oxidation in alkaline media
- 2022
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Ingår i: RSC Advances. - : ROYAL SOC CHEMISTRY. - 2046-2069. ; 13:1, s. 743-755
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we have prepared cobalt selenide (CoSe2) due to its useful aspects from a catalysis point of view such as abundant active sites from Se edges, and significant stability in alkaline conditions. CoSe2, however, has yet to prove its functionality, so we doped palladium oxide (PdO) onto CoSe2 nanostructures using ultraviolet (UV) light, resulting in an efficient and stable water oxidation composite. The crystal arrays, morphology, and chemical composition of the surface were studied using a variety of characterization techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) spectroscopy. It was also demonstrated that the composite systems were heterogeneous in their morphology, undergoing a shift in their diffraction patterns, suffering from a variety of metal oxidation states and surface defects. The water oxidation was verified by a low overpotential of 260 mV at a current density of 20 mA cm(-2) with a Tafel Slope value of 57 mV dec(-1). The presence of multi metal oxidation states, rich surface edges of Se and favorable charge transport played a leading role towards water oxidation with a low energy demand. Furthermore, 48 h of durability is associated with the composite system. With the use of PdO and CoSe2, new, low efficiency, simple electrocatalysts for water catalysis have been developed, enabling the development of practical energy conversion and storage systems. This is an excellent alternative approach for fostering growth in the field.
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| 5. |
- Adelani, David, et al.
(författare)
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A Few Thousand Translations Go A Long Way! Leveraging Pre-trained Models for African News Translation
- 2022
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Ingår i: NAACL 2022. - Stroudsburg : Association for Computational Linguistics. - 9781955917711 ; , s. 3053-3070
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Konferensbidrag (refereegranskat)abstract
- Recent advances in the pre-training of language models leverage large-scale datasets to create multilingual models. However, low-resource languages are mostly left out in these datasets. This is primarily because many widely spoken languages are not well represented on the web and therefore excluded from the large-scale crawls used to create datasets. Furthermore, downstream users of these models are restricted to the selection of languages originally chosen for pre-training. This work investigates how to optimally leverage existing pre-trained models to create low-resource translation systems for 16 African languages. We focus on two questions: 1) How can pre-trained models be used for languages not included in the initial pre-training? and 2) How can the resulting translation models effectively transfer to new domains? To answer these questions, we create a new African news corpus covering 16 languages, of which eight languages are not part of any existing evaluation dataset. We demonstrate that the most effective strategy for transferring both to additional languages and to additional domains is to fine-tune large pre-trained models on small quantities of high-quality translation data.
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| 6. |
- Aftab, Umair, et al.
(författare)
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Mixed CoS2@Co3O4 composite material: An efficient nonprecious electrocatalyst for hydrogen evolution reaction
- 2020
-
Ingår i: International journal of hydrogen energy. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0360-3199 .- 1879-3487. ; 45:27, s. 13805-13813
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Tidskriftsartikel (refereegranskat)abstract
- Hydrogen evolution reaction (HER) has been identified as a sustainable and environment friendly technology for a wide range of energy conversion and storage applications. The big barrier in realizing this green technology requires a highly efficient, earth-abundant, and low-cost electrocatalyst for HER. Various HER catalysts have been designed and reported, still, their performance is not up to the mark of Pt. Among them, cobalt-based, especially cobalt disulfide (CoS2) has shown significant HER activity and found suitable candidature for HER due to its low cost, simple to prepare, and exhibits good stability. Herein, we synthesized various nanostructured materials including pure CoS2, Co3O4 and their composites by wet chemical methods and found them active for HER. The scanning electron microscopy (SEM) has revealed a morphology of composite as a mixture of nanowires and round shape spherical nanoparticles with several microns in dimension. The X-ray diffraction (XRD) confirmed the cubic phase of CoS2 and cubic phase of Co3O4 in the composite materials. The chemical deposition of CoS2 onto Co3O4 has tailored the HER activity of CoS2@Co3O4 composite material. Two CoS2@Co3O4 composite materials were produced with varying amounts of Co3O4 and labeled as samples 1 and 2. The Co3O4 reduced the adsorption energy for hydrogen, decreased the aggregation of CoS2 and uplifted the stability of CoS2@Co3O4 a composite material in alkaline media. Sample 1 requires an overpotential of 320 mV to reach a current density of 10 mA/cm(2) and it exhibits a Tafel slope of 42 mVdec(-1) which is the key indicator for the fast HER kinetics on sample 1. The sample 1 is highly durable for 50 h and also it has excellent stability. The electrochemical impedance spectroscopy (EIS) revealed a small charge transfer resistance of 28.81 Ohms for the sample 1 with high capacitance double-layer value of 0.81 mF. EIS has supported polarization and Tafel slope results. Based on the partial physical characterization and the electrochemical results, the as-obtained sample 1 (CoS2@Co3O4 composite material) will find potential applications in an extended range of energy conversion and storage devices owing to its low cost, high abundance, and excellent efficiency. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
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| 7. |
- Aftab, Umair, et al.
(författare)
-
Nickel-cobalt bimetallic sulfide NiCo(2)S(4)nanostructures for a robust hydrogen evolution reaction in acidic media
- 2020
-
Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 10:37, s. 22196-22203
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Tidskriftsartikel (refereegranskat)abstract
- There are many challenges associated with the fabrication of efficient, inexpensive, durable and very stable nonprecious metal catalysts for the hydrogen evolution reaction (HER). In this study, we have designed a facile strategy by tailoring the concentration of precursors to successfully obtain nickel-cobalt bimetallic sulfide (NiCo2S4) using a simple hydrothermal method. The morphology of the newly prepared NiCo(2)S(4)comprised a mixture of microparticles and nanorods, which were few microns in dimension. The crystallinity of the composite sample was found to be excellent with a cubic phase. The sample that contained a higher amount of cobalt compared to nickel and produced single-phase NiCo(2)S(4)exhibited considerably improved HER performance. The variation in the salt precursor concentration during the synthesis of a material is a simple methodology to produce a scalable platinum-free catalyst for HER. The advantageous features of the multiple active sites of cobalt in the CN-21 sample as compared to that for pristine CoS and NiS laid the foundation for the provision of abundant active edges for HER. The composite sample produced a current density of 10 mA cm(-2)at an overpotential of 345 mV. Also, it exhibited a Tafel value of 60 mV dec(-1), which predominantly ensured rapid charge transfer kinetics during HER. CN-21 was highly durable and stable for 30 hours. Electrochemical impedance spectroscopy showed that the charge transfer resistance was 21.88 ohms, which further validated the HER polarization curves and Tafel results. CN-21 exhibited a double layer capacitance of 4.69 mu F cm(-2)and a significant electrochemically active surface area of 134.0 cm(2), which again supported the robust efficiency for HER. The obtained results reveal that our developed NiCo(2)S(4)catalyst has a high density of active edges, and it is a non-noble metal catalyst for the hydrogen evolution reaction. The present findings provide an alternative strategy and an active nonprecious material for the development of energy-related applications.
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| 8. |
- Aftab, Umair, et al.
(författare)
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The chemically reduced CuO-Co3O4 composite as a highly efficient electrocatalyst for oxygen evolution reaction in alkaline media
- 2019
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Ingår i: Catalysis Science & Technology. - : ROYAL SOC CHEMISTRY. - 2044-4753 .- 2044-4761. ; 9:22, s. 6274-6284
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Tidskriftsartikel (refereegranskat)abstract
- The fabrication of efficient, alkaline-stable and nonprecious electrocatalysts for the oxygen evolution reaction is highly needed; however, it is a challenging task. Herein, we report a noble metal-free advanced catalyst, i.e. the chemically reduced mixed transition metal oxide CuO-Co3O4 composite, with outstanding oxygen evolution reaction activity in alkaline media. Sodium borohydride (NaBH4) was used as a reducing agent for the mixed transition metal oxide CuO-Co3O4. The chemically reduced composite carried mixed valence states of Cu and Co, which played a dynamic role in driving an excellent oxygen evolution reaction process. The X-ray photo-electron spectroscopy (XPS) study confirmed high density of active sites in the treated sample with a large number of oxygen vacancies. The developed electrocatalyst showed the lowest overpotential of 144.5 mV vs. the reversible hydrogen electrode (RHE) to achieve the current density of 40 mA cm(-2) and remained stable for 40 hours throughout the chronoamperometry test at the constant potential of 1.39 V vs. RHE. Moreover, the chemically reduced composite was highly durable. Electrochemical impedance spectroscopy (EIS) confirmed the low charge transfer resistance of 13.53 ohms for the chemically reduced composite, which was 50 and 26 times smaller than that of Co3O4 and untreated CuO-Co3O4, respectively. The electrochemically active surface area for the chemically reduced composite was found to be greater than that for pristine CuO, Co3O4 and untreated pristine CuO-Co3O4. These findings reveal the possibility of a new gateway for the capitalization of a chemically reduced sample into diverse energy storage and conversion systems such as lithium-ion batteries and supercapacitors.
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| 9. |
- Aftab, Umair, et al.
(författare)
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Two step synthesis of TiO2–Co3O4 composite for efficient oxygen evolution reaction
- 2021
-
Ingår i: International journal of hydrogen energy. - : Elsevier. - 0360-3199 .- 1879-3487. ; 46:13, s. 9110-9122
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Tidskriftsartikel (refereegranskat)abstract
- For an active hydrogen gas generation through water dissociation, the sluggish oxygen evolution reaction (OER) kinetics due to large overpotential is a main hindrance. Herein, a simple approach is used to produce composite material based on TiO2/Co3O4 for efficient OER and overpotential is linearly reduced with increasing amount of TiO2. The scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM) investigations reveal the wire like morphology of composite materials, formed by the self-assembly of nanoparticles. The titania nanoparticles were homogenously distributed on the larger Co3O4 nanoparticles. The powder x-ray diffraction revealed a tetragonal phase of TiO2 and the cubic phase of Co3O4 in the composite materials. Composite samples with increasing TiO2 content were obtained (18%, 33%, 41% and 65% wt.). Among the composites, cobalt oxide-titanium oxide with the highest TiO2 content (CT-20) possesses the lowest overpotential for OER with a Tafel slope of 60 mV dec−1 and an exchange current density of 2.98 × 10−3A/cm2. The CT-20 is highly durable for 45 h at different current densities of 10, 20 and 30 mA/cm2. Electrochemical impedance spectroscopy (EIS) confirmed the fast charge transport for the CT-20 sample, which potentially accelerated the OER kinetics. These results based on a two-step methodology for the synthesis of TiO2/Co3O4 material can be useful and interesting for various energy storage and energy conversion systems.
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| 10. |
- Amin, Muhammad Umair, et al.
(författare)
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Co-delivery of carbonic anhydrase IX inhibitor and doxorubicin as a promising approach to address hypoxia-induced chemoresistance
- 2022
-
Ingår i: Drug Delivery. - : Informa UK Limited. - 1071-7544 .- 1521-0464. ; 29:1, s. 2072-2085
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Tidskriftsartikel (refereegranskat)abstract
- Hypoxia, an oxygen-deprived condition of the tumor, is one of the major reasons for resistance to chemotherapy. Carbonic anhydrases are generally involved in pH homeostasis in normal conditions, but in solid tumors having a strong relation with hypoxia, the carbonic anhydrase IX (CA-IX) enzyme is overexpressed and results in an extracellular acidic environment. For most weakly basic anticancer drugs, including doxorubicin (Dox), the ionization in an acidic environment limits their cellular uptake, and consequently, the tumor exposure to the drug at sub-therapeutic concentration comes out as chemoresistance. Herein, a combined drug delivery system of liposomes and mesoporous silica nanoparticles (MSNPs) was developed for the co-delivery of the CA-IX enzyme inhibitor and Dox in hypoxic condition. The unique structure of MSNPs with higher surface area was utilized for higher drug loading and sustained release of Dox. Additionally, the biocompatible nature of liposomal coating as a second loading site for the CA-IX enzyme inhibitor has provided gatekeeping effects at pore opening to avoid premature drug release. Lipid coated MSNPs as a co-delivery system for Dox and the CA-IX inhibitor have synergistic cytotoxic effects against MDA-MB 231 breast cancer cells in hypoxic conditions. These findings assure the potential of this drug delivery system to overcome hypoxia-related chemoresistance.
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| 11. |
- Amin, Muhammad Umair, et al.
(författare)
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Ultrasound-Responsive Smart Drug Delivery System of Lipid Coated Mesoporous Silica Nanoparticles
- 2021
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Ingår i: Pharmaceutics. - : MDPI. - 1999-4923. ; 13:9
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Tidskriftsartikel (refereegranskat)abstract
- The immediate release of chemotherapeutics at the target site, along with no premature release in circulation is always challenging. The purpose of this study was to develop a stimuli responsive drug delivery system, composed of lipid supported mesoporous silica nanoparticles (MSNPs) for triggered drug release at the target site and simultaneously avoiding the premature release. MSNPs with a higher drug loading capacity and very slow release were designed so as to enhance release by FDA approved US-irradiation. Doxorubicin, as a model drug, and perfluoropentane (PFP) as a US responsive material, were entrapped in the porous structure of MSNPs. Lipid coating enhanced the cellular uptake and in addition provided a gatekeeping effect at the pore opening to reduce premature release. The mechanical and thermal effects of US induced the conversion of liquid PFP to a gaseous form that was able to rupture the lipid layer, resulting in triggered drug release. The prolonged stability profile and non-toxic behavior made them suitable candidate for the delivery of anticancer drugs. This smart system, with the abilities of better cellular uptake and higher cytotoxic effects on US-irradiation, would be a good addition to the applied side of chemotherapeutic advanced drug delivery systems.
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| 12. |
- Manzoor, Numair, et al.
(författare)
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RETRACTED: Experimental Study of CO2 Conversion into Methanol by Synthesized Photocatalyst (ZnFe2O4/TiO2) Using Visible Light as an Energy Source
- 2020
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Ingår i: Catalysts. - : MDPI. - 2073-4344. ; 10:2
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Tidskriftsartikel (refereegranskat)abstract
- Ozone layer depletion is a serious threat due to the extensive release of greenhouse gases. The emission of carbon dioxide (CO2) from fossil fuel combustion is a major reason for global warming. Energy demands and climate change are coupled with each other. CO2is a major gas contributing to global warming; hence, the conversion of CO2 into useful products such as methanol, formic acid, formaldehyde, etc., under visible light is an attractive topic. Challenges associated with the current research include synthesizing a photocatalyst that is driven by visible light with a narrow band gap range between 2.5 and 3.0 eV, the separation of a mixed end product, and the two to three times faster recombination rate of an electron–hole pair compared with separation over yield. The purpose of the current research is to convert CO2 into useful fuel i.e., methanol; the current study focuses on the photocatalytic reduction of CO2into a useful product. This research is based on the profound analysis of published work, which allows the selection of appropriate methods and material for this research. In this study, zinc ferrite (ZnFe2O4) is synthesized via the modified sol–gel method and coupled with titanium dioxide (TiO2). Thereafter, the catalyst is characterized by Fourier transform infrared (FTIR), FE-SEM, UV–Vis, and XRD characterization techniques. UV–Vis illustrates that the synthesized catalyst has a low band gap and utilizes a major portion of visible light irradiation. The XRD pattern was confirmed by the formation of the desired catalyst. FE-SEM illustrated that the size of the catalyst ranges from 50 to 500 nm and BET analysis determined the surface area, which was 2.213 and 6.453 m2/g for ZnFe2O4 and ZnFe2O4/TiO2, respectively. The continuous gas flow photoreactor was used to study the activity of the synthesized catalyst, while titanium dioxide (TiO2) has been coupled with zinc ferrite (ZnFe2O4) under visible light in order to obtain the maximum yield of methanol as a single product and simultaneously avoid the conversion of CO2 into multiple products. The performance of ZnFe2O4/TiO2was mainly assessed through methanol yield with a variable amount of TiO2 over ZnFe2O4 (1:1, 1:2, 2:1, 1:3, and 3:1). The synthesized catalyst recycling ability has been tested up to five cycles. Finally, we concluded that the optimum conditions for maximum yield were found to be a calcination temperature of ZnFe2O4at 900 °C, and optimum yield was at a 1:1 w/w coupling ratio of ZnFe2O4/TiO2. It was observed that due to the enhancement in the electron–hole pair lifetime, the methanol yield at 141.22 μmol/gcat·h over ZnFe2O4/TiO2was found to be 7% higher than the earlier reported data.
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| 13. |
- Solangi, Muhammad Yameen, et al.
(författare)
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In-situ growth of nonstoichiometric CrO0.87 and Co3O4 hybrid system for the enhanced electrocatalytic water splitting in alkaline media
- 2023
-
Ingår i: International journal of hydrogen energy. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0360-3199 .- 1879-3487. ; 48:93, s. 36439-36451
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Tidskriftsartikel (refereegranskat)abstract
- The development of electrocatalysts for electrochemical water splitting has received considerable attention in response to the growing demand for renewable energy sources and environmental concerns. In this study, a simple hydrothermal growth approach was developed for the in-situ growth of non-stoichiometric CrO0.87 and Co3O4 hybrid materials. It is apparent that the morphology of the prepared material shows a heterogeneous aggregate of irregularly shaped nanoparticles. Both CrO0.87 and Co3O4 have cubic crystal structures. Its chemical composition was governed by the presence of Co, Cr, and O as its main constituents. For understanding the role CrO0.87 plays in the half-cell oxygen evolu-tion reaction (OER) in alkaline conditions, CrO0.87 was optimized into Co3O4 nanostructures. The hybrid material with the highest concentration of CrO0.87 was found to be highly efficient at driving OER reactions at 255 mV and 20 mA cm(-2). The optimized material demonstrated excellent durability for 45 h and a Tafel slope of 56 mV dec(-1). Several factors may explain the outstanding performance of CrO0.87 and Co3O4 hybrid materials, including multiple metallic oxidation states, tailored surface properties, fast charge transport, and surface defects. An alternative method is proposed for the preparation of new generations of electrocatalysts for the conversion and storage of energy. (c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
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| 14. |
- Abbasi, Amir Zaib, et al.
(författare)
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Engagement in educational games and quality of life in early and middle childhood : evidence from a developing country
- 2023
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Ingår i: Current Psychology. - : Springer. - 1046-1310 .- 1936-4733. ; 42, s. 19386-19400
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Tidskriftsartikel (refereegranskat)abstract
- Serious games (SGs), are gaining prominence as a tool for early education at home as well as in school settings. Given the mixed effects of gamification on various aspects of users' lives, it is pertinent to study its broader effects on a child's pre-school and school years. Given the lack of consensus on a comprehensive measure that encapsulates these effects on an individual's routine functioning, the present study examined whether various engagement states in SGs use influence a relatively broader measure of users' functioning across significant life domains such as Quality of Life (QoL). It is argued that it would serve scholars, teachers, and parents better to understand the broader implications of SGs on children's overall QoL rather than isolated physiological and behavioral effects. Consequently, utilizing structural equation modeling, results from 335 parents of 2-10-year-olds in a developing country showed that cognitive and behavioral engagement in gamified applications appear to influence the child's QoL, but not affective engagement. Results are discussed in terms of the consequences of using game-based technology for a child's development, with far-reaching academic, personal, physical, and social implications not only for the school-going ages, but also for early teenage years. The results are promising in relation to QoL. The findings indicate the role modern technology plays in improving individuals' lives. The findings provide scholars, parents, and creators of SGs important information for their plan of action regarding children's exposure to SGs and making SGs a frequent aspect of the learning experience early in life.
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| 15. |
- Ahmed Khand, Aftab, et al.
(författare)
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Synthesis of Sheet Like Nanostructures of NiO Using Potassium Dichromate as Surface Modifying Agent for the Sensitive and Selective Determination of Amlodipine Besylate (ADB) Drug
- 2021
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Ingår i: Electroanalysis. - : WILEY-V C H VERLAG GMBH. - 1040-0397 .- 1521-4109. ; 33:5, s. 1121-1128
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Tidskriftsartikel (refereegranskat)abstract
- The monitoring of hypertension drugs is very critical and important to sustain a healthy life. In this study, we have synthesized nickel oxide (NiO) nanostructures using potassium dichromate as surface modifying agent by hydrothermal method. These NiO nanostructures were found highly active for the oxidation of ADB besylate (ADB). The unit cell structure and morphology were investigated by scanning electron microscopy (SEM) and powder X-ray diffraction (XRD) techniques. The SEM study has confirmed the nano sheet like morphology and XRD analysis has described the cubic unit arrays of NiO. After the physical characterization, NiO nanostructures were used to modify the surface of glassy carbon electrode (GCE) by drop casting method. Then cyclic voltammetry (CV) was used to characterize the electrochemical activity of NiO nanostructures in the0.1 M phosphate buffer solution of pH 10.0 and a well resolved oxidation peak was identified at 0.70 V. The linear range for the NiO nanostructures was observed from 20-90 nM with a regression coefficient of 0.99 using CV. The calculated limit of detection (LOD) was 2.125 nM and the limit of quantification (LOQ) was 4.08 nM. Further to validate the CV calibration plot, an amperometry experiment was performed on the NiO nanostructures and sensors exhibited a linear range of 10 nM to 115 nM with LOD of 1.15 nM. The proposed approach was successfully used for the determination of ADB from commercial tablets and it reveals that the sensor could be capitalized to monitor ADB concentrations from pharmaceutical products. The use of potassium dichromate as a surface modifying agent for the metal oxide nanostructures may be of great interest to manipulate their crystal and surface properties for the extended range of biomedical and energy related applications.
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| 16. |
- Alfaras, Miquel, et al.
(författare)
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Biosensing and Actuation-Platforms Coupling Body Input-Output Modalities for Affective Technologies
- 2020
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Ingår i: Sensors. - : MDPI AG. - 1424-8220. ; 20:21
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Tidskriftsartikel (refereegranskat)abstract
- Research in the use of ubiquitous technologies, tracking systems and wearables within mental health domains is on the rise. In recent years, affective technologies have gained traction and garnered the interest of interdisciplinary fields as the research on such technologies matured. However, while the role of movement and bodily experience to affective experience is well-established, how to best address movement and engagement beyond measuring cues and signals in technology-driven interactions has been unclear. In a joint industry-academia effort, we aim to remodel how affective technologies can help address body and emotional self-awareness. We present an overview of biosignals that have become standard in low-cost physiological monitoring and show how these can be matched with methods and engagements used by interaction designers skilled in designing for bodily engagement and aesthetic experiences. Taking both strands of work together offers unprecedented design opportunities that inspire further research. Through first-person soma design, an approach that draws upon the designer's felt experience and puts the sentient body at the forefront, we outline a comprehensive work for the creation of novel interactions in the form of couplings that combine biosensing and body feedback modalities of relevance to affective health. These couplings lie within the creation of design toolkits that have the potential to render rich embodied interactions to the designer/user. As a result we introduce the concept of "orchestration". By orchestration, we refer to the design of the overall interaction: coupling sensors to actuation of relevance to the affective experience; initiating and closing the interaction; habituating; helping improve on the users' body awareness and engagement with emotional experiences; soothing, calming, or energising, depending on the affective health condition and the intentions of the designer. Through the creation of a range of prototypes and couplings we elicited requirements on broader orchestration mechanisms. First-person soma design lets researchers look afresh at biosignals that, when experienced through the body, are called to reshape affective technologies with novel ways to interpret biodata, feel it, understand it and reflect upon our bodies.
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| 17. |
- Alfaras, Miquel, et al.
(författare)
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From Biodata to Somadata
- 2020
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Konferensbidrag (refereegranskat)abstract
- Biosensing technologies are increasingly available as off-the-shelf products, yet for many designers, artists and non-engineers, these technologies remain difficult to design with. Through a soma design stance, we devised a novel approach for exploring qualities in biodata. Our explorative process culminated in the design of three artefacts, coupling biosignals to tangible actuation formats. By making biodata perceivable as sound, in tangible form or directly on the skin, it became possible to link qualities of the measurements to our own somatics - our felt experience of our bodily bioprocesses - as they dynamically unfold, spurring somatically-grounded design discoveries of novel possible interactions. We show that making biodata attainable for a felt experience - or as we frame it: turning biodata into somadata - enables not only first-person encounters, but also supports collaborative design processes as the somadata can be shared and experienced dynamically, right at the moment when we explore design ideas.
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| 18. |
- Bhatti, Adeel Liaquat, et al.
(författare)
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Nanostructured Co3O4 electrocatalyst for OER : The role of organic polyelectrolytes as soft templates
- 2021
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Ingår i: Electrochimica Acta. - : Elsevier. - 0013-4686 .- 1873-3859. ; 398
-
Tidskriftsartikel (refereegranskat)abstract
- Designing an efficient electrocatalyst for the oxygen evolution reaction (OER) in alkaline media is highly needed but very challenging task. Herein, we used organic polyelectrolytes such as (carboxymethyl cellulose) CMC and polyacrylamide polymers for the growth of Co3O4 nanostructures by aqueous chemical growth method. The morphology and composition studies were performed on scanning electron microscopy (SEM), energy dispersive X-ray (EDX), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HRTEM) techniques. The structural properties and the surface chemistry of the Co3O4 electrocatalysts were correlated to the OER performance, and the enhancement mechanism with respect to pristine Co3O4 was observed to be specifically related to the polyelectrolyte templating role.Co3O4@CMC composites displayed reduced crystallite size, producing OER overpotential as low as 290 mV at 10 mAcm−2 in 1.0 KOH and Tafel slope of 71 mVdec−1, suggesting fast transfer of intermediates and electrons during water electrolysis. On the other hand, the use of polyacrylamide and its different templating mechanism resulted in similar crystallite size, but preferential exposed faces and larger surface vacancies content, as demonstrated by HR-TEM and XPS, respectively. Consistently, this material displays cutting-edge OER performance, such as overpotential of 260 mV at 10 mAcm−2 and a low Tafel slope of 63 mVdec−1. The proposed strategy for the preparation of Co3O4 nanostructures in the presence of CMC and polyacrylamide is facile, mass production, thus it could equally contributed towards the realization of hydrogen energy. Therefore, these nanostructures of Co3O4 can be regarded as an alternative and promising materials for the different electrochemical applications including fuel cells, metal air batteries, overall water electrolysis and other energy storage devices.
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| 19. |
- Claisse, Caroline, et al.
(författare)
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Tangible Interaction for Supporting Well-being
- 2022
-
Ingår i: CHI EA '22. - New York, NY, USA : Association for Computing Machinery (ACM). - 9781450391566
-
Konferensbidrag (refereegranskat)abstract
- Our workshop aims to bring together researchers and practitioners across disciplines in HCI who share an interest in promoting well-being through tangible interaction. The workshop forms an impassioned response to the worldwide push towards more digital and remote interaction in nearly all domains of our lives in the context of the COVID-19 pandemic. One question we raise is: to what extent will measures like remote interaction remain in place post-pandemic, and to what extent these changes may influence future agendas for the design of interactive products and services to support living well? We aim to ensure that the workshop serves as a space for diverse participants to share ideas and engage in cooperative discussions through hands-on activities resulting in the co-creation of a Manifesto to demonstrate the importance of embodied and sensory interaction for supporting well-being in a post-pandemic context. All the workshop materials will be published online on the workshop website and disseminated through ongoing collaboration.
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| 20. |
- Hassaan, Muhammad Umair, et al.
(författare)
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Highly Efficient Energy Transfer in Light Emissive Poly(9,9-dioctylfluorene) and Poly(p-phenylenevinylene) Blend System
- 2018
-
Ingår i: ACS Photonics. - : AMER CHEMICAL SOC. - 2330-4022. ; 5:2, s. 607-613
-
Tidskriftsartikel (refereegranskat)abstract
- A polymer blend system F8(1-x):SYx based on poly(9,9-dioctylfluorene) (F8) from the family of polyfluorenes (PFO) and a poly(para-phenylenevinylene) (PPV) derivative superyellow (SY) shows highly efficient energy transfer from F8 host to SY guest molecules. This has been realized due to a strong overlap between F8 photoemission and SY photoabsorption spectra and negligibly low self-absorption. The steady-state and time-correlated spectroscopic measurements show an increased photo-luminescence quantum efficiency (PLQE) and lifetime (tau) of SY, with an opposite trend of decreasing PLQE and tau of F8 excitons with increasing SY concentration, suggesting the Forster resonance energy transfer (FRET) to be the main decay pathway in the proposed system. The systematic study of the exciton dynamics shows a complete energy transfer at 10% of SY in the F8 host matrix and a Forster radius of similar to 6.3 nm. The polymer blend system exhibits low laser and amplified spontaneous emission thresholds. An ultrahigh efficiency (27 cd.A(-1)) in F8(1-x):SYx based light emitting diodes (LED) has been realized due to the intrinsic property of a well-balanced charge transport within the emissive layer. The dual pathway, that is, the efficient energy transfer between the blended molecules via resonance energy transfer, and the charge-traps-assisted balanced transport makes the system promising for achieving highly efficient devices and a potential candidate for lasing applications.
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| 21. |
- Höök, Kristina, 1964-, et al.
(författare)
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Unpacking Non-Dualistic Design : The Soma Design Case
- 2021
-
Ingår i: ACM Transactions on Computer-Human Interaction. - : Association for Computing Machinery (ACM). - 1073-0516 .- 1557-7325. ; 28:6
-
Tidskriftsartikel (refereegranskat)abstract
- We report on a somaesthetic design workshop and the subsequent analytical work aiming to demystify what is entailed in a non-dualistic design stance on embodied interaction and why a first-person engagement is crucial to its unfoldings. However, as we will uncover through a detailed account of our process, these first-person engagements are deeply entangled with second- and third-person perspectives, sometimes even overlapping. The analysis furthermore reveals some strategies for bridging the body-mind divide by attending to our inner universe and dissolving or traversing dichotomies between inside and outside; individual and social; body and technology. By detailing the creative process, we show how soma design becomes a process of designing with and through kinesthetic experience, in turn letting us confront several dualisms that run like fault lines through HCI's engagement with embodied interaction.
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| 22. |
- Khan, Sharifuzzaman, et al.
(författare)
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Retinal Image Enhancement Using Laplacian Pyramidal Multi-scaling
- 2014
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Ingår i: IEEE TENSYMP 2014 - 2014 IEEE Region 10 Symposium. - 9781479920280 ; , s. 141-146
-
Konferensbidrag (refereegranskat)abstract
- Early detection of retinal diseases is important to avoid complications and permanent vision loss. In this paper retinal neovascularization and molecular degeneration has been emphasized. Neovascularization is in form of randomly disoriented micro vessels in retina. So image enhancement techniques are excellent way to extract the vessels, find out blood leakages, determine direction of growth and estimate the growth rate with vessel localization. A comparative study has been done on prior retinal image enhancement algorithms. In this project multi-scale image analysis is used as main image enhancement technique with the help of Laplacian Pyramid. The target is achieved by translating an image into several image scales and reconstructing with enhancement tools available in MATLAB image processing toolbox. Results are evaluated with object background contrast ratio, contrast- noise -ratio and 2-D contour plot. The enhanced images appear as a better source for edge detection and vessel extraction compare with the primary image. For this project normal fundus images from publicly available database are chosen.
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| 23. |
- Khokhar, Shams Parveen, et al.
(författare)
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An Efficient Nickel Sulfide@NiO Nanocomposite Catalyst with High Density of Active Sites for the Hydrogen Evolution Reaction in Alkaline Media
- 2021
-
Ingår i: Journal of Nanoscience and Nanotechnology. - : AMER SCIENTIFIC PUBLISHERS. - 1533-4880 .- 1533-4899. ; 21:4, s. 2520-2528
-
Tidskriftsartikel (refereegranskat)abstract
- Efficient hydrogen evolution reaction (HER) catalysts based on the earth-abundant materials are highly vital to design practical and environmentally friendly water splitting devices. In this study, we present an optimized strategy for the development of active catalysts for hydrogen evolution reaction HER. The composite catalysts are prepared with the nanosurface of NiO for the deposition of NiS by hydrothermal method. In alkaline electrolyte, the NIS/NiO nanocomposite has shown excellent catalytic HER properties at the low onset potential and small Tafel slope of 72 mV dec(-1). A current density of 10 mA/cm(2) is achieved by the nanocomposite obtained with 0.4 gram of NiO as nanosurface for the deposition of NiS (sample 4) at the cost of 429 mV versus RHE. The sample 4 carries more active sites that allow it to act as excellent HER catalyst. Based on this study, we conclude that increasing the nickel oxide content into composite sample facilitates the HER process. Additionally, a long term HER stability for 10 hours and good durability is also demonstrated by the sample 4. Our findings reveal that the optimization of nickel oxide content in the preparation of catalyst leads to the excellent HER activity for the design of practical water splitting devices and other related applications.
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| 24. |
- Koudouridis, Georgios P., et al.
(författare)
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Performance Evaluation of Multi-Radio Transmission Diversity for TCP Flows
- 2009
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Ingår i: 2009 IEEE VEHICULAR TECHNOLOGY CONFERENCE. - 9781424425167 ; , s. 2728-2732
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Konferensbidrag (refereegranskat)abstract
- The effect of the TCP congestion control mechanism over rapidly fluctuating wireless links is a deterioration of the TCP performance. The utilization of multi-radio accesses in future networks by means of packet scheduling and dynamic access selection enriches the arsenal of solutions that mitigate radio channel variations. Packet scheduling over multiple radio accesses at link level provides a novel diversity scheme referred to as Multi-Radio Transmission Diversity (MRTD). This work evaluates, through simulations, the effects of different MRTD schemes for TCP flows over heterogeneous radio links. Results indicate that MRTD schemes provide substantial gains in terms of goodput and show a significant reduction in file download times. These gains are due to the diversity obtained and the suppression of the unwanted duplicate acknowledgements that frequently cause degradation in TCP performance over a radio channel.
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| 25. |
- Lim, Yeong Jer, et al.
(författare)
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COVID‐19 outcomes in haematopoietic cell transplant recipients : A systematic review and meta‐analysis
- 2022
-
Ingår i: eJHaem. - USA : John Wiley & Sons. - 2688-6146. ; 3:3, s. 862-872
-
Tidskriftsartikel (refereegranskat)abstract
- Up-to-date information on coronavirus disease 2019 (COVID-19) outcomes and risk factors in haematopoietic cell transplantation (HCT) recipients is required to inform on decisions about cancer treatment and COVID-19 mitigation strategies. We performed a meta-analysis to address this knowledge gap. All studies with at least five patients who reported COVID-19-related deaths in HCT recipients were included. The primary outcome was COVID-19-related death. Secondary outcomes were COVID-19-related mechanical ventilation (MV) and intensive care unit (ITU) admission. The cumulative COVID-19-related death rate among HCT recipients was 21% (95% confidence interval [CI] 18%–24%), while MV and ITU admission rates were 14% (95% CI 11%–17%) and 18% (95% CI 14%–22%), respectively. Subgroup analysis showed higher death rates in patients who developed COVID-19 within 12 months of HCT (risk ratio [RR] 1.82, 95% CI 1.09–3.03), within 6 months of receiving immunosuppressant drugs (RR 2.11, 95% CI 1.38–3.20) or in the context of active graft-versus-host disease (RR 2.38, 95% CI 1.10–5.16). Our findings support the idea that HCT should remain an integral part of cancer treatment during the COVID-19 pandemic but also highlight the need to prioritise preventative measures in those patients who are at increased risk of adverse COVID-19 outcomes.
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| 26. |
- Mugheri, Abdul Qayoom, et al.
(författare)
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A Low Charge Transfer Resistance CuO Composite for Efficient Oxygen Evolution Reaction in Alkaline Media
- 2021
-
Ingår i: Journal of Nanoscience and Nanotechnology. - : AMER SCIENTIFIC PUBLISHERS. - 1533-4880 .- 1533-4899. ; 21:4, s. 2613-2620
-
Tidskriftsartikel (refereegranskat)abstract
- An efficient, simple, environment-friendly and inexpensive cupric oxide (CuO) electrocatalyst for oxygen evolution reaction (OER) is demonstrated. CuO is chemically deposited on the porous carbon material obtained from the dehydration of common sugar. The morphology of CuO on the porous carbon material is plate-like and monoclinic crystalline phase is confirmed by powder X-ray diffraction. The OER activity of CuO nanostructures is investigated in 1 M KOH aqueous solution. To date, the proposed electrocatalyst has the lowest possible potential of 1.49 V versus RHE (reversible hydrogen electrode) to achieve a current density of 20 mA/cm(2) among the. CuO based electrocatalysts and has Tafel slope of 115 mV dec(-1). The electrocatalyst exhibits an excellent long-term stability for 6 hours along with significant durability. The enhanced catalytic active centers of CuO on the carbon material are due to the porous structure of carbon as well as strong coupling between CuO-C. The functionalization of metal oxides or other related nanostructured materials on porous carbon obtained from common sugar provides an opportunity for the development of efficient energy conversion and energy storage systems.
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| 27. |
- Mugheri, Abdul Qayoom, et al.
(författare)
-
An advanced and efficient Co3O4/C nanocomposite for the oxygen evolution reaction in alkaline media
- 2019
-
Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 9:59, s. 34136-34143
-
Tidskriftsartikel (refereegranskat)abstract
- The design of efficient nonprecious catalysts for the hydrogen evolution reaction (HER) or the oxygen evolution reaction (OER) is a necessary, but very challenging task to uplift the water-based economy. In this study, we developed a facile approach to produce porous carbon from the dehydration of sucrose and use it for the preparation of nanocomposites with cobalt oxide (Co3O4). The nanocomposites were studied by the powder X-ray diffraction and scanning electron microscopy techniques, and they exhibited the cubic phase of cobalt oxide and porous structure of carbon. The nanocomposites showed significant OER activity in alkaline media, and the current densities of 10 and 20 mA cm(-2) could be obtained at 1.49 and 1.51 V versus reversible hydrogen electrode (RHE), respectively. The impedance study confirms favorable OER activity on the surface of the prepared nanocomposites. The nanocomposite is cost-effective and can be capitalized in various energy storage technologies.
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| 28. |
- Mugheri, Abdul Qayoom, et al.
(författare)
-
Chemically Coupled Cobalt Oxide Nanosheets Decorated onto the Surface of Multiwall Carbon Nanotubes for Favorable Oxygen Evolution Reaction
- 2021
-
Ingår i: Journal of Nanoscience and Nanotechnology. - : AMER SCIENTIFIC PUBLISHERS. - 1533-4880 .- 1533-4899. ; 21:4, s. 2660-2667
-
Tidskriftsartikel (refereegranskat)abstract
- Cobalt oxide has been widely investigated among potential transition metal oxides for the electrochemical energy conversion, storage, and water splitting. However, they have inherently low electronic conductivity and high corrosive nature in alkaline media. Herein, we propose a promising and facile approach to improve the conductivity and charge transport of cobalt oxide Co3O4 through chemical coupling with well-dispersed multiwall carbon nanotubes (MWCNTs) during hydrothermal treatment. The morphology of prepared composite material consisting of nanosheets which are anchored on the MWCNTs as confirmed by scanning electron microscopy (SEM). A cubic crystalline system is exhibited by the cobalt oxide as confirmed by the X-ray diffraction study. The Co, O, and C are the only elements present in the composite material. FTIR study has indicated the successful coupling of cobalt oxide with MWCNTs. The chemically coupled cobalt oxide onto the surface of MWCNTs composite is found highly active towards oxygen evolution reaction (OER) with a low onset potential 1.44 V versus RHE, low overpotential 262 mV at 10 mAcm(-2) and small Tafel slope 81 mV dec(-1). For continuous operation of 40 hours during durability test, no decay in activity was recorded. Electrochemical impedance study further revealed a low charge transfer resistance of 70.64 Ohms for the composite material during the electrochemical reaction and which strongly favored OER kinetics. This work provides a simple, low cost, and smartly designing electrocatalysts via hydrothermal reaction for the catalysis and energy storage applications.
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| 29. |
- Mugheri, Abdul Qayoom, et al.
(författare)
-
Efficient tri-metallic oxides NiCo2O4/CuO for the oxygen evolution reaction
- 2019
-
Ingår i: RSC ADVANCES. - : ROYAL SOC CHEMISTRY. - 2046-2069. ; 9:72, s. 42387-42394
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, a simple approach was used to produce nonprecious, earth abundant, stable and environmentally friendly NiCo2O4/CuO composites for the oxygen evolution reaction (OER) in alkaline media. The nanocomposites were prepared by a low temperature aqueous chemical growth method. The morphology of the nanostructures was changed from nanowires to porous structures with the addition of CuO. The NiCo2O4/CuO composite was loaded onto a glassy carbon electrode by the drop casting method. The addition of CuO into NiCo2O4 led to reduction in the onset potential of the OER. Among the composites, 0.5 grams of CuO anchored with NiCo2O4 (sample 2) demonstrated a low onset potential of 1.46 V vs. a reversible hydrogen electrode (RHE). A current density of 10 mA cm(-2) was achieved at an over-potential of 230 mV and sample 2 was found to be durable for 35 hours in alkaline media. Electrochemical impedance spectroscopy (EIS) indicated a small charge transfer resistance of 77.46 ohms for sample 2, which further strengthened the OER polarization curves and indicates the favorable OER kinetics. All of the obtained results could encourage the application of sample 2 in water splitting batteries and other energy related applications.
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| 30. |
- Mugheri, Abdul Qayoom, et al.
(författare)
-
Facile efficient earth abundant NiO/C composite electrocatalyst for the oxygen evolution reaction Electronic supplementary information (ESI) available. See DOI: 10.1039/c8ra10472g
- 2019
-
Ingår i: RSC Advances. - : ROYAL SOC CHEMISTRY. - 2046-2069. ; 9:10, s. 5701-5710
-
Tidskriftsartikel (refereegranskat)abstract
- Due to the increasing energy consumption, designing efficient electrocatalysts for electrochemical water splitting is highly demanded. In this study, we provide a facile approach for the design and fabrication of efficient and stable electrocatalysts through wet chemical methods. The carbon material, obtained by the dehydration of sucrose sugar, provides high surface area for the deposition of NiO nanostructures and the resulting NiO/C catalysts show higher activity towards the OER in alkaline media. During the OER, a composite of NiO with 200 mg C can produce current densities of 10 and 20 mA cm(-2) at a bias of 1.45 V and 1.47 V vs. RHE, respectively. Electrochemical impedance spectroscopy experiments showed the lowest charge transfer resistance and the highest double layer capacitance in the case of the NiO/C composite with 200 mg C. The presence of C for the deposition of NiO nanostructures increases the active centers and consequently a robust electrocatalytic activity is achieved. The obtained results in terms of the low overpotential and small Tafel slope of 55 mV dec(-1) for non-precious catalysts are clear indications for the significant advancement in the field of electrocatalyst design for water splitting. This composite material based on NiO/C is simple and scalable for widespread use in various applications, especially in supercapacitors and lithium-ion batteries.
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| 31. |
- Nguyen, Thanh N, et al.
(författare)
-
Global Impact of the COVID-19 Pandemic on Stroke Volumes and Cerebrovascular Events: A 1-Year Follow-up.
- 2023
-
Ingår i: Neurology. - 1526-632X. ; 100:4
-
Tidskriftsartikel (refereegranskat)abstract
- Declines in stroke admission, IV thrombolysis (IVT), and mechanical thrombectomy volumes were reported during the first wave of the COVID-19 pandemic. There is a paucity of data on the longer-term effect of the pandemic on stroke volumes over the course of a year and through the second wave of the pandemic. We sought to measure the effect of the COVID-19 pandemic on the volumes of stroke admissions, intracranial hemorrhage (ICH), IVT, and mechanical thrombectomy over a 1-year period at the onset of the pandemic (March 1, 2020, to February 28, 2021) compared with the immediately preceding year (March 1, 2019, to February 29, 2020).We conducted a longitudinal retrospective study across 6 continents, 56 countries, and 275 stroke centers. We collected volume data for COVID-19 admissions and 4 stroke metrics: ischemic stroke admissions, ICH admissions, IVT treatments, and mechanical thrombectomy procedures. Diagnoses were identified by their ICD-10 codes or classifications in stroke databases.There were 148,895 stroke admissions in the 1 year immediately before compared with 138,453 admissions during the 1-year pandemic, representing a 7% decline (95% CI [95% CI 7.1-6.9]; p < 0.0001). ICH volumes declined from 29,585 to 28,156 (4.8% [5.1-4.6]; p < 0.0001) and IVT volume from 24,584 to 23,077 (6.1% [6.4-5.8]; p < 0.0001). Larger declines were observed at high-volume compared with low-volume centers (all p < 0.0001). There was no significant change in mechanical thrombectomy volumes (0.7% [0.6-0.9]; p = 0.49). Stroke was diagnosed in 1.3% [1.31-1.38] of 406,792 COVID-19 hospitalizations. SARS-CoV-2 infection was present in 2.9% ([2.82-2.97], 5,656/195,539) of all stroke hospitalizations.There was a global decline and shift to lower-volume centers of stroke admission volumes, ICH volumes, and IVT volumes during the 1st year of the COVID-19 pandemic compared with the prior year. Mechanical thrombectomy volumes were preserved. These results suggest preservation in the stroke care of higher severity of disease through the first pandemic year.This study is registered under NCT04934020.
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| 32. |
- Qayoom Mugheri, Abdul, et al.
(författare)
-
Co3O4/ NiO bifunctional electrocatalyst for water splitting
- 2019
-
Ingår i: Electrochimica Acta. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0013-4686 .- 1873-3859. ; 306
-
Tidskriftsartikel (refereegranskat)abstract
- The development of noble metal free and active bifunctional catalysts for water splitting in alkaline media is highly demanded but very challenging. Herein, synergetic effects developed between two nonprecious metal oxides, Co3O4 and NiO, are reported, with the resulting composite showing promising properties as a catalyst for alkaline water electrolysis. The activity of the composite material towards both the HER and the OER was enhanced and the dynamic potential decreased, as compared with its counterparts. Importantly, low Tafel slopes of 101 and 61 mVdec(-1) are found for the composite catalyst for OER and HER respectively. EIS measurements revealed a decreased impedance response of the composite dominated by the intermediate frequency relaxation, related to the adsorption of intermediates. Moreover, based on the structural features the improved catalytic activity of the composite is also due to high electroactive surface area, swift electron transfer kinetics, and excellent electrical chemical coupling between Co3O4 and NiO. (c) 2019 Elsevier Ltd. All rights reserved.
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| 33. |
- Rafique, Umair, et al.
(författare)
-
Uni-Planar MIMO Antenna for Sub-6 GHz 5G Mobile Phone Applications
- 2022
-
Ingår i: Applied Sciences. - : MDPI AG. - 2076-3417. ; 12:8
-
Tidskriftsartikel (refereegranskat)abstract
- This article presents the design of a uni-planar MIMO antenna system for sub-6 GHz 5G-enabled smartphones. The MIMO antenna designed comprises four loop-shaped radiators placed at each corner of the mobile phone board, which follows the principle of pattern diversity. The single-antenna element resonates at 3.5 GHz, its impedance bandwidth is noted to be 1.28 GHz (3-4.28 GHz) for S-11 <= -6 dB, and it is equal to 720 MHz (3.18-3.9 GHz) for S-11 <= -10 dB. For a single-antenna element, a peak gain of 3.64 dBi is observed with an antenna efficiency of >90%. The isolation of >10 dB between antenna elements is achieved for the MIMO configuration. Furthermore, the MIMO antenna designed provides enough radiation coverage to support different sides of the mobile phone board, which is an important feature for future 5G-enabled handsets. In addition, the impacts of human hands and heads on MIMO antenna performance are investigated, and acceptable performance in the data and conversation modes is observed.
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| 34. |
- Salama, Suzy, et al.
(författare)
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Royal Jelly : Beneficial Properties and Synergistic Effects with Chemotherapeutic Drugs with Particular Emphasis in Anticancer Strategies
- 2022
-
Ingår i: Nutrients. - : MDPI. - 2072-6643. ; 14:19
-
Forskningsöversikt (refereegranskat)abstract
- Cancer is one of the major causes of death globally. Currently, various methods are used to treat cancer, including radiotherapy, surgery, and chemotherapy, all of which have serious adverse effects. A healthy lifestyle, especially a nutritional diet, plays a critical role in the treatment and prevention of many disorders, including cancer. The above notion, plus the trend in going back to nature, encourages consumers and the food industry to invest more in food products and to find potential candidates that can maintain human health. One of these agents, and a very notable food agent, is royal jelly (RJ), known to be produced by the hypopharyngeal and mandibular salivary glands of young nurse honeybees. RJ contains bioactive substances, such as carbohydrates, protein, lipids, peptides, mineral salts and polyphenols which contribute to the appreciated biological and pharmacological activities. Antioxidant, anticancer, anti-inflammatory, antidiabetic, and antibacterial impacts are among the well-recognized benefits. The combination of RJ or its constituents with anticancer drugs has synergistic effects on cancer disorders, enhancing the drug's effectiveness or reducing its side effects. The purpose of the present review is to emphasize the possible interactions between chemotherapy and RJ, or its components, in treating cancer illnesses.
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| 35. |
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| 36. |
- Tahira, Aneela, et al.
(författare)
-
An efficient bifunctional electrocatalyst based on a nickel iron layered double hydroxide functionalized Co3O4 core shell structure in alkaline media
- 2019
-
Ingår i: Catalysis Science & Technology. - : Royal Society of Chemistry. - 2044-4753 .- 2044-4761. ; 9:11, s. 2879-2887
-
Tidskriftsartikel (refereegranskat)abstract
- Developing highly active nonprecious metal and binder free bifunctional electrocatalysts for water splitting is a challenging task. In this study, we used a simple strategy to deposit a nickel iron layered double hydroxide (NiFeLDH) onto cobalt oxide (Co3O4) nanowires. The cobalt oxide nanowires are covered with thin nanosheets of NiFeLDH forming a core shell structure. The Co3O4 nanowires contain the mixed oxidation states of Co2+ and Co3+, and the surface modification of Co3O4 nanowires has shown synergetic effects due to there being more oxygen defects, catalytic sites, and enhanced electronic conductivity. Further, the core shell structure of Co3O4 nanowires demonstrated a bifunctional activity for water splitting in 1 M KOH aqueous solution. From the hydrogen evolution reaction (HER), a current density of 10 mA cm - 2 is achieved at a potential of - 0.303 V vs. reversible hydrogen electrode (RHE). Meanwhile for the case of the oxygen evolution reaction (OER), a current density of 40 mA cm - 2 is measured at a potential of 1.49 V vs. RHE. Also, this electrocatalyst has shown a considerable long- term stability of 15 h for both the HER and the OER. Importantly, electrochemical impedance spectroscopy has shown that the NiFeLDH integration onto cobalt oxide exhibited around 3 fold decrease of charge transfer resistance for both the HER and the OER in comparison with pristine cobalt oxide films, which reveals an excellent electrocatalytic activity for both faradaic processes. All these results confirm that the proposed electrocatalyst can be integrated into an efficient water splitting system.
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| 37. |
- Umair Hassan, Muhammad, et al.
(författare)
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Low Thresholds for a Nonconventional Polymer Blend-Amplified Spontaneous Emission and Lasing in F8(1-x):SYx System
- 2016
-
Ingår i: Journal of Polymer Science Part B. - : WILEY-BLACKWELL. - 0887-6266 .- 1099-0488. ; 54:1, s. 15-21
-
Tidskriftsartikel (refereegranskat)abstract
- A mixture of two polymer materials, poly (9,9-dioctylfluorene) (F8), and one of the poly(para-phenylenevinylene) derivatives, superyellow (SY) have been used to make F8(1-x):SYx polymer blend system. Under a 3-5 ns pulsed-laser excitation, this system showed excellent optical properties with low threshold values of approximate to 14 mJ/cm(2) and approximate to 8 mJ/cm(2) for amplified spontaneous emission and optically pumped lasing, respectively. The proposed system was also electroluminescent and an interesting candidate for future research on polymer injection lasers. (C) 2015 Wiley Periodicals, Inc.
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| 38. |
- Umair, Muhammad, et al.
(författare)
-
A search for resonances in the p mu e system
- 2014
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Ingår i: Journal of Physics B. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 47:17
-
Tidskriftsartikel (refereegranskat)abstract
- The charge radius of the proton has recently been determined from 2s-2p spectroscopy of muonic hydrogen, giving a result which significantly deviates from earlier measurements. One hypothesis is that this discrepancy could arise because a metastable p mu e state is formed under the p mu (2s) threshold. We search for such a state by considering the three-body pex and p mu x systems, where x is a particle with charge -e and a mass which is varied between the electron and muon mass. We identify a new class of resonances, which extends the mass range allowing formation of resonances compared to an earlier work. We conclude that no p mu e resonances relevant for 2s-2p spectroscopy in muonic hydrogen can exist.
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| 39. |
- Umair, Muhammad, et al.
(författare)
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Automatic frequency planning and optimization algorithm for cellular networks
- 2012
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Ingår i: Proceedings of the World Congress on Engineering 2012 Volume I & Volume II & Volume III. - : Newswood Limited. - 9789881925213 ; , s. 1287-1291
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Konferensbidrag (refereegranskat)abstract
- Frequency planning in ever growing cellular networks is an extremely arduous task. Any effort to lay down manual frequency plans promulgates inefficiency in the cellular radio systems. The extensive deployment and penetration of cellular networks necessitate the need to carry out automatic frequency planning. This paper presents a novel and ingenious algorithm for automatic generation and optimization of the frequency plan whereby curtailing the intra-system interference levels within the acceptable ranges of the key performance indicators (KPI’s) defined for any real time cellular network. The automatic frequency planning and optimization has been done using the concept of Inter-Cell Dependency Matrix (ICDM) which contains cell correlations in terms of the affect one cell has on the other primarily with regards to the co-channel interference. The proposed algorithm was simulated in MATLAB. It has been set forth and tested using inputs from live network data. It has been found to satisfy the verifiable network performance metrics.
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| 40. |
- Umair, Muhammad, et al.
(författare)
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Natural and unnatural parity resonance states in positron-hydrogen scattering
- 2014
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Ingår i: Journal of Physics B. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 47:22
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Tidskriftsartikel (refereegranskat)abstract
- We present an investigation of resonances with natural and unnatural parities in positron scattering with atomic hydrogen. The complex scaling method has been used. Resonance states for natural parity pi=(-1)(J) with total angular momenta J = 0 - 2 and unnatural parity pi = (-1)(J+1) with J = 1, 2 are calculated. Resonance energies and widths are reported and compared with other theoretical calculations.
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| 41. |
- Umair, Muhammad, et al.
(författare)
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Positronium-dipole induced resonances in e(+)-H and e(+)-alkali systems
- 2017
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Ingår i: Journal of Physics B. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 50:4
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Tidskriftsartikel (refereegranskat)abstract
- We derive general universal scaling relations governing resonances induced by the dipole moment of excited positronium interacting with atomic ions. A single non-universal parameter, which contains all the system-dependent information, is defined. Our results are compared to numerical calculations, using complex scaling, for S, P, and D-wave resonances below the positronium n. =. 2 threshold in the e(+)-(H, Li, Na, K) systems. The energy and width ratios of the successive resonances are found to agree well with the analytically derived scaling law.
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| 42. |
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| 43. |
- Umair, Muhammad, et al.
(författare)
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Resonances in a positron-lithium (e+−Li) system
- 2016
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Ingår i: Physical Review A: covering atomic, molecular, and optical physics and quantum information. - 2469-9926 .- 2469-9934. ; 93:5
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Tidskriftsartikel (refereegranskat)abstract
- The method of complex scaling is used to calculate S- and P-wave resonance energies and widths below the Li(3s, 3p, 4s, 4p) excitation thresholds and positronium n = 2 formation threshold in the positron-lithium system. We use two different types of model potentials to determine the interaction between the core and the valence electron. Explicitly correlated Gaussian basis functions are used to represent the correlation effects between the valence electron, the positron, and the Li+ core. A dipole series of resonances are found under the positronium n = 2 threshold. Furthermore, these resonances are found to agree well with an analytically derived scaling law. The present results are compared with those in the literature.
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| 44. |
- Umair, Muhammad, et al.
(författare)
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Resonances in positron-potassium ($e^{+}$-K) system with natural and unnatural parities
- 2016
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Ingår i: Journal of Physics B. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 49:1
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Tidskriftsartikel (refereegranskat)abstract
- We present an investigation of resonances with natural and unnatural parities in the positron-potassium system using the complex scaling method. A model potential is used to represent the interaction between the core and the valence electron. Explicitly correlated Gaussian wave functions are used to represent the correlation effects between the valence electron, the positron and the K+ core. Resonance energies and widths for two partial waves (S- and P-wave) below the K(4p, 5s, 5p, 4d, 4f) excitation thresholds and positronium n = 2 formation threshold are calculated for natural parity. Resonance states for P-e below the K(4d) excitation threshold and positronium n = 2, 3 formation thresholds are calculated for unnatural parity which has not been previously reported. Below both positronium thresholds we have found a dipole series of resonances, with binding energies scaling in good agreement with exceptions from an analytical calculation. The present results are compared with those in the literature.
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| 45. |
- Umair, Muhammad, 1984-
(författare)
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Resonances in three-body systems
- 2014
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Three particles interacting via Coulomb forces represents a fundamental problem in quantum mechanics whose approximate solution provides some insight into the more complex analysis associated with few-body problems. We have investigated resonance states composed of three particles interacting via Coulombic and more general potentials in non-relativistic quantum mechanics, using the complex scaling method. My calculations have been applied to two different physical systems: (i) an investigation of the possibility of resonances in the $p e \mu$ system, which has been suggested as a possible reason for unexpected results from a recent measurement of the proton radius in muonic hydrogen (ii) a calculation of resonances in positron-hydrogen scattering, which shows that we can represent this system with the accuracy needed for future scattering calculations. The basis set used is built from Gaussians in Jacobi coordinates, thus automatically including mass-polarisation effects which cannot be neglected in muonic systems.
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| 46. |
- Umair, Muhammad, 1984-
(författare)
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Resonances in Three-Body Systems
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Three particles interacting via Coulomb forces represent a fundamental problem in quantum mechanics with no known exact solution. We have investigated resonance states composed of three particles interacting via Coulombic and more general potentials in non-relativistic quantum mechanics, using the complex scaling method. Our calculations have been applied to three different systems.(i) An investigation of resonances in the positron-alkali (Li, Na, K) systems has been conducted. Some calculations have previously been reported on the resonances in positron-alkali systems; however, most of the work was limited to the lower partial wave, such as S-wave resonances. In this thesis, we have extended the calculations to higher partial waves and extracted the resonance positions and widths using the more accurate complex scaling method. A dipole series of resonances has been found under positronium n = 2 threshold, for natural parity and n = 3 threshold for unnatural parity states. Furthermore, these resonances were found to agree well with an analytically derived scaling law. This series in the positron-alkali system are caused by the attractive potential formed by the dipole moment of positronium (the bound state of an electron and a positron). This dipole moment is a hydrogen-like system, and hence its energy levels are degenerate with respect to orbital angular momentum. We have also predicted several new resonances.(ii) A calculation of resonances in positron-hydrogen scattering, which shows that we can represent this system with the accuracy needed for future scattering calculations. Such cross sections are of interest since this is a way to form anti-hydrogen.(iii) A search for possible resonances in the pµe system, which has been suggested as a possible reason for unexpected results from a recent measurement of the proton radius in muonic hydrogen. We have ruled out the possibility of such resonances.In all calculations we used the Couple Rearrangement Channel Method, where the wave function is represented by Gaussians expressed in Jacobi coordinates. Thus effects due to mass polarization are automatically.
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| 47. |
- Umair, Muhammad, et al.
(författare)
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Resonances with natural and unnatural parities in positron-sodium scattering
- 2015
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Ingår i: Physical Review A: covering atomic, molecular, and optical physics and quantum information. - 2469-9926 .- 2469-9934. ; 92:1
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Tidskriftsartikel (refereegranskat)abstract
- We present an investigation of resonances in positron-sodium scattering using the complex scaling method. For the target sodium atoms, the interaction between the core and outer electron is treated using two different types of analytical model potentials. Explicitly correlated Gaussian wave functions are used to represent the correlation effects between the outer electron, the positron, and the Na+ core. S-, P-, and D-wave resonances with natural parity have been calculated for energies extending up to the positronium n = 2 formation threshold. Resonance states for unnatural parities Pe and D0 have been calculated for energies extending up to the positronium n = 3 threshold. Below both positronium thresholds we have for each symmetry identified a dipole series of resonances, with binding energies scaling in good agreement with expectations from an analytical calculation. The presented results are compared with other theoretical calculations.
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| 48. |
- Yamashita, Takuma, et al.
(författare)
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Bound and resonance states of positronic copper atoms
- 2017
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Ingår i: Journal of Physics B. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 50:20
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Tidskriftsartikel (refereegranskat)abstract
- We report a theoretical calculation for the bound and S-wave resonance states of the positronic copper atom (e(+) Cu). A positron is a positively charged particle; therefore, a positronic atom has an attractive correlation between the positron and electron. A Gaussian expansion method is adopted to directly describe this correlation as well as the strong repulsive interaction with the nucleus. The correlation between the positron and electron is much more important than that between electrons in an analogous system of Cu-, although the formation of a positronium (Ps) in e(+) Cu is not expressed in the ground state structure explicitly. Resonance states are calculated with a complex scaling method and identified above the first excited state of the copper atom. Resonance states below Ps (n = 2) + Cu+ classified to a dipole series show agreement with a simple analytical law. Comparison of the resonance energies and widths of e(+) Cu with those of e(+) K, of which the potential energy of the host atom resembles that of e(+) Cu, reveals that the positions of the resonance for the e(+) Cu dipole series deviate equally from those of e(+) K.
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| 49. |
- Zahid, Muhammad Noaman, et al.
(författare)
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H-Shaped Eight-Element Dual-Band MIMO Antenna for Sub-6 GHz 5G Smartphone Applications
- 2022
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Ingår i: IEEE Access. - : Institute of Electrical and Electronics Engineers (IEEE). - 2169-3536. ; 10, s. 85619-85629
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Tidskriftsartikel (refereegranskat)abstract
- The design of an eight-element H-shaped dual-band multiple-input multiple-output (MIMO) antenna system for sub-6 GHz fifth-generation (5G) smartphone applications is presented in this work. The radiating elements are designed on the side edge frame of the smartphone, placed on both sides of the main printed circuit board (PCB). Each side edge consists of four radiating elements, which ensures low mutual coupling between antenna elements. The total size of the main PCB is 150 x 75 mm(2), while the size of the side edge frame is 150 x 7 mm(2). A single antenna consists of an H-shaped radiating element fed using a 50 Omega microstrip feeding line designed on the main board of the smartphone. The results show that, according to -6 dB impedance bandwidth criteria, the designed MIMO antenna radiates at two different frequency ranges within the allocated 5G spectrums, i.e., 3.1-3.78 GHz and 5.43-6.21 GHz with 680 MHz and 780 MHz bandwidths, respectively. It is also observed that the antenna elements are able to provide pattern diversity for both the frequency bands. Furthermore, an isolation of >12 dB is observed between any two given radiating elements. Numerous MIMO critical performance characteristics are assessed, including diversity gain (DG), envelope correlation coefficient (ECC), and channel capacity (CC). A prototype is built, measured, and it is observed that the measured and simulated data correspond well. On the basis of performance characteristics, it can be claimed that the suggested MIMO system may be used in 5G communication networks.
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