| 1. |
- Hussain Ibupoto, Zafar, et al.
(author)
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Low temperature synthesis of seed mediated CuO bundle of nanowires, their structural characterisation and cholesterol detection
- 2013
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In: Materials science & engineering. C, biomimetic materials, sensors and systems. - : Elsevier. - 0928-4931 .- 1873-0191. ; 33:7, s. 3889-3898
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Journal article (peer-reviewed)abstract
- In this study, we have successfully synthesised CuO bundle of nanowires using simple, cheap and low temperature hydrothermal growth method. The growth parameters such as precursor concentration and time for duration of growth were optimised. The field emission scanning electron microscopy (FESEM) has demonstrated that the CuO bundles of nanowires are highly dense, uniform and perpendicularly oriented to the substrate. The high resolution transmission electron microscopy (HRTEM) has demonstrated that the CuO nanostructures consist of bundle of nanowires and their growth pattern is along the [010] direction. The X-ray diffraction (XRD) technique described that CuO bundle of nanowires possess the monoclinic crystal phase. The surface and chemical composition analyses were carried out with X-ray photoelectron spectroscopy (XPS) technique and the obtained results suggested the pure crystal state of CuO nanostructures. In addition, the CuO nanowires were used for the cholesterol sensing application by immobilising the cholesterol oxidase through electrostatic attraction. The infrared reflection absorption spectroscopy study has also revealed that CuO nanostructures are consisting of only Cu-O bonding and has also shown the possible interaction of cholesterol oxidase with the sharp edge surface of CuO bundle of nanowires. The proposed cholesterol sensor has demonstrated the wide range of detection of cholesterol with good sensitivity of 33.88 +/- 0.96 mV/decade. Moreover, the CuO bundle of nanowires based sensor electrode has revealed good repeatability, reproducibility, stability, selectivity and a fast response time of less than 10 s. The cholesterol sensor based on the immobilised cholesterol oxidase has good potential applicability for the determination of cholesterol from the human serum and other biological samples.
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| 2. |
- Hussain Ibupoto, Zafar, et al.
(author)
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Selective zinc ion detection by functionalised ZnO nanorods with ionophore
- 2011
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In: Journal of Applied Physics. - : American Institute of Physics (AIP). - 0021-8979 .- 1089-7550. ; 110:10, s. 104702-
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Journal article (peer-reviewed)abstract
- In this paper, highly dense and well aligned single-crystal zinc oxide nanorods were grown along the c-axis on a gold coated glass substrate using a low temperature aqueous chemical growth approach. The prepared ZnO nanorods were functionalized with plastic membrane coatings containing specific ionophore (12-crown-4) which is highly selective to zinc ions (Zn(+2)). The electrochemical response of the sensor was found to be linear over a relatively wide logarithmic concentration range from 1 mu M to 100mM. The proposed sensor showed a good linearity with a high sensitivity of similar to 35 mV/decade for sensing Zn(+2) ions. A fast response time of less than 5 s with a good selectivity, repeatability, reproducibility, and negligible response to common interferents ions such as calcium (Ca(2+)), magnesium (Mg(2+)), or potassium (K(+)), and iron (Fe(+3)) and copper (Cu(+2)) was also demonstrated. Moreover, the proposed sensor showed good stoichiometric results for potentiometric titration.
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| 3. |
- Hussain Ibupoto, Zafar, et al.
(author)
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The synthesis of CuO nanoleaves, structural characterization, and their glucose sensing application
- 2013
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In: Applied Physics Letters. - : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 102:10
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Journal article (peer-reviewed)abstract
- The present study describes the synthesis of well aligned and highly dense polyethylene glycol template assisted cupric oxide (CuO) nanoleaves on the gold coated glass substrate by hydrothermal growth method. The structural study based investigations of CuO nanoleaves were performed by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX), infrared reflection-absorption spectroscopy (IRAS), and high resolution transmission electron microscopy (HRTEM). The glucose sensor based on the glucose oxidase immobilized CuO nanoleaves electrode detected the wide range of glucose concentrations with good linearity and exhibited high sensitivity of 61.9+/-2.0 mV/decade. The linear detection range was observed from 1.0 x 10(-5) to 2.0 x 10(-2) M with detection limit of 5.0 x 10(-6) M and a fast response time of less than 5 s was also observed. The glucose sensor electrode possesses good anti-interference ability, stability, repeatability, and reproducibility.
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| 4. |
- Hussain Ibupoto, Zafar, et al.
(author)
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Well aligned ZnO nanorods growth on the gold coated glass substrate by aqueous chemical growth method using seed layer of Fe3O4 and Co3O4 nanoparticles
- 2013
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In: Journal of Crystal Growth. - : Elsevier. - 0022-0248 .- 1873-5002. ; 368, s. 39-46
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Journal article (peer-reviewed)abstract
- In this study, Fe3O4 and Co3O4 nanoparticles were prepared by co-precipitation method and sol-gel method respectively. The synthesised nanoparticles were characterised by X-ray diffraction [XRD] and Raman spectroscopy techniques. The obtained results have shown the nanocrystalline phase of obtained Fe3O4 and Co3O4 nanoparticles. Furthermore, the Fe3O4 and Co3O4 nanoparticles were used as seed layer for the fabrication of well-aligned ZnO nanorods on the gold coated glass substrate by aqueous chemical growth method. Scanning electron microscopy (SEM), high resolution transmission electron microscopy [HRTEM], as well as XRD and energy dispersive X-ray techniques were used for the structural characterisation of synthesised ZnO nanorods. This study has explored highly dense, uniform, well-aligned growth pattern along 0001 direction and good crystal quality of the prepared ZnO nanorods. ZnO nanorods are only composed of Zn and O atoms. Moreover, X-ray photoelectron spectroscopy was used for the chemical analysis of fabricated ZnO nanorods. In addition, the structural characterisation and the chemical composition study and the optical investigation were carried out for the fabricated ZnO nanorods and the photoluminescence [PL] spectrum have shown strong ultraviolet (UV) peak at 381 nm for Fe3O4 nanoparticles seeded ZnO nanorods and the PL spectrum for ZnO nanorods grown with the seed layer of Co3O4 nanoparticles has shown a UV peak at 382 nm. The green emission and orange/red peaks were also observed for ZnO nanorods grown with both the seed layers. This study has indicated the fabrication of well aligned ZnO nanorods using the one inorganic nanomaterial on other inorganic nanomaterial due to their similar chemistry.
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| 5. |
- Khun, K., et al.
(author)
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Urea Assisted Synthesis of Flower Like CuO Nanostructures and Their Chemical Sensing Application for the Determination of Cadmium Ions
- 2013
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In: Electroanalysis. - : Wiley-VCH Verlag. - 1040-0397 .- 1521-4109. ; 25:6, s. 1425-1432
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Journal article (peer-reviewed)abstract
- The novel nanostructures of CuO with improved morphology are strongly required for the development of devices with enhanced performance. In this study flower like nanostructures of CuO are synthesized by hydrothermal method using urea as tuning material for the morphology of CuO during the growth process. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques were used for the characterization of these nanostructures. The nanostructures are highly dense, uniform and well aligned on the gold coated glass substrate. Moreover, CuO nanostructures exhibited pure phase of CuO. These novel CuO nanostructures were potentially used for the construction of cadmium ion sensor by functionalizing with tetrathia-12-crown-4 a selective cadmium ion ionophore. The proposed cadmium ion sensor has detected the wide range of cadmium ion concentrations from 1.0x10-9-1.0x10-1M with a sensitivity of 29.3 +/- 0.3mV/decade and also a fast response time of less than 10.0s is demonstrated. CuO nanostructures based cadmium ion selective electrode has also shown excellent reproducibility, repeatability, selectivity, and stability. The sensor electrode was also used as indicator electrode for the confirmation of practical utility and the obtained result describes the good behavior of the sensor in the potentiometric titration for the determination of cadmium ions.
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| 6. |
- Meskó, Norbert, et al.
(author)
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Exploring Attitudes Toward “Sugar Relationships” Across 87 Countries : A Global Perspective on Exchanges of Resources for Sex and Companionship
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In: Archives of Sexual Behavior. - 0004-0002.
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Journal article (peer-reviewed)abstract
- The current study investigates attitudes toward one form of sex for resources: the so-called sugar relationships, which often involve exchanges of resources for sex and/or companionship. The present study examined associations among attitudes toward sugar relationships and relevant variables (e.g., sex, sociosexuality, gender inequality, parasitic exposure) in 69,924 participants across 87 countries. Two self-report measures of Acceptance of Sugar Relationships (ASR) developed for younger companion providers (ASR-YWMS) and older resource providers (ASR-OMWS) were translated into 37 languages. We tested cross-sex and cross-linguistic construct equivalence, cross-cultural invariance in sex differences, and the importance of the hypothetical predictors of ASR. Both measures showed adequate psychometric properties in all languages (except the Persian version of ASR-YWMS). Results partially supported our hypotheses and were consistent with previous theoretical considerations and empirical evidence on human mating. For example, at the individual level, sociosexual orientation, traditional gender roles, and pathogen prevalence were significant predictors of both ASR-YWMS and ASR-OMWS. At the country level, gender inequality and parasite stress positively predicted the ASR-YWMS. However, being a woman negatively predicted the ASR-OMWS, but positively predicted the ASR-YWMS. At country-level, ingroup favoritism and parasite stress positively predicted the ASR-OMWS. Furthermore, significant cross-subregional differences were found in the openness to sugar relationships (both ASR-YWMS and ASR-OMWS scores) across subregions. Finally, significant differences were found between ASR-YWMS and ASR-OMWS when compared in each subregion. The ASR-YWMS was significantly higher than the ASR-OMWS in all subregions, except for Northern Africa and Western Asia.
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| 7. |
- Willander, Magnus, et al.
(author)
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UV detectors and LEDs in different metal oxide nanostructures
- 2014
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Conference paper (peer-reviewed)abstract
- Different composite nanostructures based pn-junctions have been synthesized using the low temperature hydrothermal chemical growth. The composite nanostructures based pn junctions demonstrated here include p-NiO/n-ZnO, p-CuO/n-ZnO, and p-NiO/n-TiO2. Structural characterization of these composite nanostructures based pn-junctions was performed by different complementary tools and the results indicated that reasonable device quality crystals have been achieved. His act was also confirmed by the rectifying electrical behavior observed from these junctions. Further, the different composite nanostructures based junctions were used to demonstrate UV detectors and visible light emitting diodes (LEDs) operating with acceptable performance.
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