| 1. |
- Aminoff, A, et al.
(författare)
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Allele-specific regulation of MTTP expression influences the risk of ischemic heart disease.
- 2010
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Ingår i: Journal of lipid research. - 0022-2275 .- 1539-7262. ; 51:1, s. 103-11
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Tidskriftsartikel (refereegranskat)abstract
- Promoter polymorphisms in microsomal triglyceride transfer protein (MTTP) have been associated with decreased plasma lipids but an increased risk for ischemic heart disease (IHD), indicating that MTTP influences the susceptibility for IHD independent of plasma lipids. The objective of this study was to characterize the functional promoter polymorphism in MTTP predisposing to IHD and its underlying mechanism. Use of pyrosequencing technology revealed that presence of the minor alleles of the promoter polymorphisms -493G>T and -164T>C result in lower transcription of MTTP in vivo in the heart, liver, and macrophages. In vitro experiments indicated that the minor -164C allele mediates the lower gene expression and that C/EBP binds to the polymorphic region in an allele-specific manner. Furthermore, homozygous carriers of the -164C were found to have increased risk for IHD as shown in a case-control study including a total of 544 IHD patients and 544 healthy control subjects. We concluded that carriers of the minor -164C allele have lower expression of MTTP in the heart, mediated at least partly by the transcription factor CCAAT/enhancer binding protein, and that reduced concentration of MTTP in the myocardium may contribute to IHD upon ischemic damage.
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| 2. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 3. |
- Bellani, Sebastiano, et al.
(författare)
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Graphene-Based Electrodes in a Vanadium Redox Flow Battery Produced by Rapid Low-Pressure Combined Gas Plasma Treatments
- 2021
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Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 33:11, s. 4106-4121
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Tidskriftsartikel (refereegranskat)abstract
- The development of high-power density vanadium redox flow batteries (VRFBs) with high energy efficiencies (EEs) is crucial for the widespread dissemination of this energy storage technology. In this work, we report the production of novel hierarchical carbonaceous nanomaterials for VRFB electrodes with high catalytic activity toward the vanadium redox reactions (VO2+/VO2+ and V2+/V3+). The electrode materials are produced through a rapid (minute timescale) low-pressure combined gas plasma treatment of graphite felts (GFs) in an inductively coupled radio frequency reactor. By systematically studying the effects of either pure gases (O-2 and N-2) or their combination at different gas plasma pressures, the electrodes are optimized to reduce their kinetic polarization for the VRFB redox reactions. To further enhance the catalytic surface area of the electrodes, single-/fewlayer graphene, produced by highly scalable wet-jet milling exfoliation of graphite, is incorporated into the GFs through an infiltration method in the presence of a polymeric binder. Depending on the thickness of the proton-exchange membrane (Nafion 115 or Nafion XL), our optimized VRFB configurations can efficiently operate within a wide range of charge/discharge current densities, exhibiting energy efficiencies up to 93.9%, 90.8%, 88.3%, 85.6%, 77.6%, and 69.5% at 25, 50, 75, 100, 200, and 300 mA cm(-2), respectively. Our technology is cost-competitive when compared to commercial ones (additional electrode costs < 100 (sic) m(-2)) and shows EEs rivalling the record-high values reported for efficient systems to date. Our work remarks on the importance to study modified plasma conditions or plasma methods alternative to those reported previously (e.g., atmospheric plasmas) to improve further the electrode performances of the current VRFB systems.
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| 4. |
- Beydaghi, Hossein, et al.
(författare)
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Functionalized metallic transition metal dichalcogenide (TaS2) for nanocomposite membranes in direct methanol fuel cells
- 2021
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry. - 2050-7488 .- 2050-7496. ; 9:10, s. 6368-6381
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we designed a novel nanocomposite proton-exchange membrane (PEM) based on sulfonated poly(ether ether ketone) (SPEEK) and tantalum disulfide functionalized with terminal sulfonate groups (S-TaS2). The PEMs are prepared through a solution-casting method and exploited in direct methanol fuel cells (DMFCs). Two-dimensional S-TaS2 nanoflakes were prepared as a functional additive to produce the novel nanocomposite membrane for DMFCs due to their potential as a fuel barrier and an excellent proton conductor. To optimize the degree of sulfonation (DS) of SPEEK and the weight percentage (wt%) of S-TaS2 nanoflakes in PEMs, we used the central composite design of the response surface method. The optimum PEM was obtained for SPEEK DS of 1.9% and a weight fraction (wt%) of S-TaS2 nanoflakes of 70.2%. The optimized membrane shows a water uptake of 45.72%, a membrane swelling of 9.64%, a proton conductivity of 96.24 mS cm(-1), a methanol permeability of 2.66 x 10(-7) cm(2) s(-1), and a selectivity of 36.18 x 10(4) S s cm(-3). Moreover, SPEEK/S-TaS2 membranes show superior thermal and chemical stabilities compared to those of pristine SPEEK. The DMFC fabricated with the SPEEK/S-TaS2 membrane has reached the maximum power densities of 64.55 mW cm(-2) and 161.18 mW cm(-2) at 30 degrees C and 80 degrees C, respectively, which are similar to 78% higher than the values obtained with the pristine SPEEK membrane. Our results demonstrate that SPEEK/S-TaS2 membranes have a great potential for DMFC applications.
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| 5. |
- Beydaghi, Hossein, et al.
(författare)
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Sulfonated NbS2-based proton-exchange membranes for vanadium redox flow batteries
- 2022
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Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3364 .- 2040-3372. ; 14:16, s. 6152-6161
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Tidskriftsartikel (refereegranskat)abstract
- In this work, novel proton-exchange membranes (PEMs) based on sulfonated poly(ether ether ketone) (SPEEK) and two-dimensional (2D) sulfonated niobium disulphide (S-NbS2) nanoflakes are synthesized by a solution-casting method and used in vanadium redox flow batteries (VRFBs). The NbS2 nanoflakes are produced by liquid-phase exfoliation of their bulk counterpart and chemically functionalized with terminal sulfonate groups to improve dimensional and chemical stabilities, proton conductivity (sigma) and fuel barrier properties of the as-produced membranes. The addition of S-NbS2 nanoflakes to SPEEK decreases the vanadium ion permeability from 5.42 x 10(-7) to 2.34 x 10(-7) cm(2) min(-1). Meanwhile, it increases the membrane sigma and selectivity up to 94.35 mS cm(-2) and 40.32 x 10(4) S min cm(-3), respectively. The cell assembled with the optimized membrane incorporating 2.5 wt% of S-NbS2 nanoflakes (SPEEK:2.5% S-NbS2) exhibits high efficiency metrics, i.e., coulombic efficiency between 98.7 and 99.0%, voltage efficiency between 90.2 and 73.2% and energy efficiency between 89.3 and 72.8% within the current density range of 100-300 mA cm(-2), delivering a maximum power density of 0.83 W cm(-2) at a current density of 870 mA cm(-2). The SPEEK:2.5% S-NbS2 membrane-based VRFBs show a stable behavior over 200 cycles at 200 mA cm(-2). This study opens up an effective avenue for the production of advanced SPEEK-based membranes for VRFBs.
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| 6. |
- Bianca, Gabriele, et al.
(författare)
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Liquid-Phase Exfoliated GeSe Nanoflakes for Photoelectrochemical-Type Photodetectors and Photoelectrochemical Water Splitting
- 2020
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Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 12:43, s. 48598-48613
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Tidskriftsartikel (refereegranskat)abstract
- Photoelectrochemical (PEC) systems represent powerful tools to convert electromagnetic radiation into chemical fuels and electricity. In this context, two-dimensional (2D) materials are attracting enormous interest as potential advanced photo(electro)catalysts and, recently, 2D group-IVA metal monochalcogenides have been theoretically predicted to be water splitting photocatalysts. In this work, we use density functional theory calculations to theoretically investigate the photocatalytic activity of single-/few-layer GeSe nanoflakes for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) in pH conditions ranging from 0 to 14. Our simulations show that GeSe nanoflakes with different thickness can be mixed in the form of nanoporous films to act as nanoscale tandem systems, in which the flakes, depending on their thickness, can operate as HER- and/or OER photocatalysts. On the basis of theoretical predictions, we report the first experimental characterization of the photo(electro)catalytic activity of single-/few-layer GeSe flakes in different aqueous media, ranging from acidic to alkaline solutions: 0.5 M H2SO4 (pH 0.3), 1 M KCl (pH 6.5), and 1 M KOH (pH 14). The films of the GeSe nanoflakes are fabricated by spray coating GeSe nanoflakes dispersion in 2-propanol obtained through liquid-phase exfoliation of synthesized orthorhombic (Pnma) GeSe bulk crystals. The PEC properties of the GeSe nanoflakes are used to design PEC-type photodetectors, reaching a responsivity of up to 0.32 AW(-1) (external quantum efficiency of 86.3%) under 455 nm excitation wavelength in acidic electrolyte. The obtained performances are superior to those of several self-powered and low-voltage solution-processed photodetectors, approaching that of self-powered commercial UV-Vis photodetectors. The obtained results inspire the use of 2D GeSe in proof-of-concept water photoelectrolysis cells.
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| 7. |
- Chatzimanolis, Konstantinos, et al.
(författare)
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Inverted perovskite solar cells with enhanced lifetime and thermal stability enabled by a metallic tantalum disulfide buffer layer
- 2021
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Ingår i: Nanoscale Advances. - : Royal Society of Chemistry. - 2516-0230. ; 3:11, s. 3124-3135
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Tidskriftsartikel (refereegranskat)abstract
- Perovskite solar cells (PSCs) have proved their potential for delivering high power conversion efficiencies (PCE) alongside low fabrication cost and high versatility. The stability and the PCE of PSCs can readily be improved by implementing engineering approaches that entail the incorporation of two-dimensional (2D) materials across the device's layered configuration. In this work, two-dimensional (2D) 6R-TaS2 flakes were exfoliated and incorporated as a buffer layer in inverted PSCs, enhancing the device's PCE, lifetime and thermal stability. A thin buffer layer of 6R-TaS2 flakes was formed on top of the electron transport layer to facilitate electron extraction, thus improving the overall device performance. The optimized devices reach a PCE of 18.45%, representing a 12% improvement compared to the reference cell. The lifetime stability measurements of the devices under ISOS-L2, ISOS-D1, ISOS-D1I and ISOS-D2I protocols revealed that the TaS2 buffer layer retards the intrinsic, thermally activated degradation processes of the PSCs. Notably, the devices retain more than the 80% of their initial PCE over 330 h under continuous 1 Sun illumination at 65 degrees C.
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| 8. |
- Eeg-Olofsson, Katarina, 1968, et al.
(författare)
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Risk of cardiovascular disease and mortality in overweight and obese patients with type 2 diabetes: an observational study in 13,087 patients.
- 2009
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Ingår i: Diabetologia. - : Springer Science and Business Media LLC. - 1432-0428 .- 0012-186X. ; 52:1, s. 65-73
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Tidskriftsartikel (refereegranskat)abstract
- AIMS/HYPOTHESIS: The aim of this study of type 2 diabetic patients in the Swedish National Diabetes Register was to study the associations of BMI, overweight (BMI 25-29.9 kg/m(2)) and obesity (BMI >or= 30 kg/m(2)) with cardiovascular disease in type 2 diabetes, as these associations have not previously been clarified. METHODS: Patients aged 30-74 years with no previous CHD or stroke (N = 13,087) were followed for a mean of 5.6 years until 2003 for fatal or non-fatal CHD, stroke, cardiovascular disease (CHD or stroke) and total mortality. In total, 1,922 cardiovascular-disease events occurred, based on 64,864 person-years. RESULTS: The relative risks of CHD, stroke, cardiovascular disease and total mortality for a 5 unit increase in BMI at baseline were 15%, 11%, 13% and 27%, respectively, using Cox regression analysis, after adjusting for age, sex, diabetes duration, hypoglycaemic treatment and smoking (model 1), and were 9%, 4% (not significant), 7% and 20%, respectively, when adjusting also for HbA(1c), blood pressure, antihypertensive drugs, lipid-reducing drugs and microalbuminuria (model 2). Adjusted hazard ratios (model 1) for CHD, cardiovascular disease and total mortality with overweight were 1.27 (95% CI 1.09-1.48), 1.24 (1.09-1.41) and 1.16 (0.94-1.45), respectively, and 1.49 (1.27-1.76), 1.44 (1.26-1.64) and 1.71 (1.36-2.14) with obesity, as compared with normal weight. Significant hazard ratios were attenuated when adjusted according to model 2. For a 1 unit increase in BMI during follow-up, the relative risk of CHD (model 2) was 1.13 (1.04-1.23; p = 0.005). CONCLUSIONS/INTERPRETATION: Both overweight and obesity independently increased the risk of CHD and cardiovascular disease in patients with type 2 diabetes. The CHD risk was higher with increasing BMI than with stable or decreasing BMI during the study.
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| 9. |
- Liedberg, Fredrik, et al.
(författare)
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Long-term follow-up after radical cystectomy with emphasis on complications and reoperations: A Swedish population-based survey
- 2012
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Ingår i: Scandinavian Journal of Urology and Nephrology. - : Informa Healthcare. - 0036-5599 .- 1651-2065. ; 46:1, s. 14-18
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Tidskriftsartikel (refereegranskat)abstract
- Objective. To evaluate outcome after radical cystectomy for primary bladder cancer in a large population-based material. Material and methods. Between 1997 and 2002 all patients treated with radical cystectomy within 3 months after diagnosis of primary bladder cancer without distant metastasis were retrieved through the Swedish Bladder Cancer Registry. A follow-up questionnaire was distributed to all units where the primary registration of patients was performed. Follow-up data on recurrence date were retrieved from the patient charts and causes of death were obtained from the Swedish Cause of Death Registry until 2003. Results. During the study period radical cystectomy was performed in 39 units in Sweden, of which only five units were considered high-volume hospitals performing 10 or more procedures annually. Mean blood loss was 2300 ml (median 2000 ml) and the 90-day mortality rate was 5.7%. Blood loss was higher in high-volume units than in hospitals with lower hospital volumes, but the 90-day mortality rates were similar. During a median follow-up of 3.5 years, 24% of the patients were submitted to a reoperation. Reoperation rates were significantly higher in patients who received a continent urinary diversion (29%) compared with an ileal conduit (22%, p andlt; 0.015). Conclusions. Radical cystectomy was associated with a reoperation rate of 24% in Sweden during the study period. The reoperation rates were higher in patients receiving a continent cutaneous diversion or bladder substitution. Blood loss was higher in high-volume units; otherwise, surgical volume did not affect mortality rates, cancer-specific survival or reoperation rates.
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| 10. |
- Najafi, Leyla, et al.
(författare)
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Hybrid Organic/Inorganic Photocathodes Based on WS2 Flakes as Hole Transporting Layer Material
- 2021
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Ingår i: Small Structures. - : John Wiley & Sons. - 2688-4062. ; 2:3
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Tidskriftsartikel (refereegranskat)abstract
- The efficient production of molecular hydrogen (H2) is a fundamental step toward an environmentally friendly economy. Photocathodes using organic bulk heterojunction (BHJ) films as light harvesters represent an attracting technology for low-cost photoelectrochemical water splitting. These photocathodes need charge transporting layers (CTLs) to efficiently separate and transport either holes or electrons toward the back-current collector and electrolyte, respectively. Therefore, it is pivotal to control the energy band edge levels and the work function (WF) of the CTLs to match the ones of the BHJ film, current collector, and electrolyte. Herein, the use of 2D p-doped WS2 flakes as hole transporting material for H2-evolving photocathodes based on the regioregular poly(3-hexylthiophene):phenyl-C61-butyric acid methyl ester (rr-P3HT:PCBM) BHJ film is proposed. The WS2 flakes are produced through scalable liquid-phase exfoliation of the bulk crystal, whereas p-type chemical doping allows the tuning of the WS2 WF. This approach boosts the performances of the photocathodes, reaching photocurrent densities up to 4.14 mA cm−2 at 0 V versus reversible hydrogen electrode (RHE), an onset potential of 0.66 V versus RHE, and a ratiometric power-saved metric of 1.28% (under 1 sun illumination). To the best of the authors' knowledge, these performances represent the current record for 2D materials-based CTLs.
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