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In this study, we investigate the factors affecting consumers’ purchase intention toward influencers’ personal owned brands. By using the theoretical lens of the Theory of Planned Behaviour (TPB) we explore consumers’ purchase intentions towards influencers own brands and discuss the importance of previously held attitudes, subjective norms and perceived behavioural control. We further develop TPB by adding two further constructs, that of price and self-identity. The reported moderator role of self-identity in the relationship between price and purchase intention under the context of influencers’ personal owned brands suggests that the ‘fan’ status of followers makes them more tolerant to price increases. We discuss theoretical implications and offer suggestions for marketers and consumers alike.

In human pancreatic β-cells, oxidative stress and cellular injures can be induced by H2O2 treatment. The KEAP1/NRF2 axis is a key antioxidant signaling pathway. The present study attempted to elucidate the mechanism by which the KEAP1/NRF2 axis mediates oxidative stress-induced death in pancreatic β-cells. Our data showed that H2O2 treatment obviously induced the apoptosis of β-cells. Further experiments demonstrated that KEAP1 expression was downregulated in H2O2-treated pancreatic β-cells and this change correlated with increase in the cellular abundance and nuclear translocation of NRF2. The restoration of KEAP1 expression in cells resulted in a recovery of cell proliferation and inhibition of apoptosis. Furthermore, we found that KEAP1 overexpression negatively regulated the abundance of NRF2, subsequently causing decreased antioxidant response element activation. This led to HO-1 protein downregulation in H2O2-treated human pancreatic β-cells, which was also observed in NRF2-silenced β-cells. Conversely, the silencing of KEAP1 led to NRF2 upregulation and inhibited ARE and HO-1 signaling in pancreatic β-cells. The increase in the abundance of NRF2 following treatment with H2O2 drastically elevated the production of BAX, FAS, FAS-L, CASP-3, and CASP-9, and this change was reversed by KEAP1 overexpression or NRF2 silencing. Taken together, H2O2 treatment activated KEAP1/NRF2 signaling to promote the production of pro-apoptotic factors and consequently led to the apoptosis of human pancreatic β-cells.

Objective To explore the effect of tanshinone IIA (TSA) on hydrogen peroxide (H

The aim of the study was to determine the influence of exendin-4 intervention on non-obese diabetic (NOD) mouse blood and the pancreatic tissue immune microenvironment. A total of 40 clean NOD mice were used in the study and randomly divided into 4 groups (n=10/group). The first group was blank control group D with normal saline intervention, and with different doses of exendin, i.e.,-4 2, 4 and 8 µg/kg/day. The three remaining groups were: i) Low-dose group A; ii) medium-dose group B; and iii) high-dose group C. Mice in the four groups went through intervention for 8 weeks. Their mass and blood glucose levels were tested each week. After 8 weeks, the mice were sacrificed, and mouse serum samples were reserved. The ELISA method was used to test peripheral blood (PB), IL-2, IFN-γ and IL-10 levels. Pancreatic samples were created. Immunohistochemistry was used to observe the infiltration degree of mouse pancreatitis and the local expression state of pancreatic IL-10. Mouse pancreatic tissues were suspended in pancreatic cell suspension. Flow cytometry was used to test the state of T-cell subsets CD4 and CD25. Mouse pancreatitis in control group D was mainly at grade 2and 3. Under a light microscope, it was observed that pancreatic cell morphology was in disorder, and the size and quantity of the pancreas was small. Mouse pancreatitis in the exendin-4 low-dose group A, medium-dose group B and high-dose group C was mainly at grade 0 and 1. Under a light microscope, it was observed that pancreatic cell morphology improved, the infiltration degree of lymphocyte was improved and pancreatic islet size was restored somewhat. Additionally, a few brownish granules were identified within the pancreatic sample cells in control group D. There were many brownish granules with deep color within the pancreatic sample cells in exendin-4 low-dose group A, medium-dose group B and high-dose group C. IL-10 immunohistochemistry scores in the low-dose group A, medium-dose group B and high-dose group C were 3.82±0.72, 4.34±0.86 and 4.81±0.94, respectively, and were higher than the score of 2.25±0.63 in control group D. CD4+CD25+T-cell proportions in mouse pancreatic tissues of low-dose group A, medium-dose group B and high-dose group C were 5.31, 5.53 and 5.74%, respectively, which were higher than that of the CD4+CD25+T-cell proportion (1.62% in control group D). The CD4+CD25high T-cell proportion in CD4+T-cells in group A, B and C increased. Compared with control group D, serum IL-10 levels in the exendin-4 low-dose group A, medium-dose group B and high-dose group C increased (P

Type I diabetes mellitus (TIDM) serves as a large contributor to morbidity as well as mortality globally with persistently elevating prevalence. It is known that oxidative damage by free radicals participates in etiology, complications, as well as progression of TIDM. In our research, we demonstrate that Keap1-Nrf2-ARE pathway was stimulated by exendin-4 treatment during the development of type I diabetes in murine TIDM model as well as in pancreatic β-cells. We also observed excessive reactive oxygen species (ROS) production, low level of cell death, and PKC phosphorylation on exendine-4 treatment. Nrf2 knockdown led to suppression of ROS generation as well as increasing apoptosis. Moreover, siRNA-mediated Nrf2 down-regulation attenuated the suppressive effect of exendin-4 in pancreatic β-cell viability, through modulating apoptosis promoting- and counteracting-proteins, Bax, and Bcl-2. Thus, the present study indicates exendin-4 mediates activation of Keap1-Nrf2-ARE pathway and may serve as a promising agent to treat TIDM. IMPACT STATEMENT: Nrf2 is an essential part of the defense mechanism of vertebrates and protects them from surrounding stress via participation in stimulated expression of detoxification as well as antioxidant enzymes. It also exerts a role in defending hosts from different stress in the environment, including reactive oxygen species. Our study investigates the role of exendin-4 on Nrf2 pathway as well as cell death in pancreatic β-cell and in non-obese diabetic mice. Result of study indicates exendin-4 mediates activation of Keap1-Nrf2-ARE pathway and may serve as a potential agent to treat type I diabetes mellitus. In our research, we observed excessive reactive oxygen species production, low level of cell death, and PKC phosphorylation on exendine-4 treatment. Nrf2 knockdown led to suppression of reactive oxygen species generation as well as increasing apoptosis. Moreover, siRNA-mediated Nrf2 down-regulation attenuated the suppressive effect of exendin-4 in pancreatic β-cell viability, via modulating apoptosis promoting- and counteracting-proteins, Bax, and Bcl-2.

BACKGROUND Growth hormone deficiency (GHD) is a major cause of congenital short stature. GHD patients have significantly decreased serum leptin levels, which are regulated by gene polymorphism of leptin and leptin receptor. This study thus investigated the relationship between gene polymorphism and susceptibility to GHD. MATERIAL AND METHODS A case-control study was performed using 180 GHD children in addition to 160 healthy controls. After the extraction of whole genomic DNA, the genotypes of leptin and leptin receptor gene loci were analyzed by sequencing for single-nucleotide polymorphism. RESULTS The frequency distribution of all alleles identified in leptin gene (loci rs7799039) and leptin receptor gene (loci rs1137100 and rs1137101) fit Hardy-Weinberg equilibrium. There was a significant difference in allele frequency at loci rs7799039 or rs1137101, as individuals with heterozygous GA allele had lower (rs7799039) or higher (rs1137101) GHD risk. No significant difference in allele frequency was discovered at loci rs1137100 (p>0.05), which was unrelated to GHD susceptibility. CONCLUSIONS Gene polymorphism of leptin (loci rs7799039) and leptin receptor (loci rs1137101) are correlated with GHD susceptibility.

In human pancreatic β-cells, oxidative stress and cellular injures can be induced by H

s This study investigates the TiO x compact layers deposited by mid-frequency magnetron sputtering of Ti target under a gaseous atmosphere of Ar/O 2 . X-ray photoelectron spectroscopy suggests that the compact layer consists of 55% Ti 3+ and 45% Ti 4+ . Current–voltage measurements reveal that the TiO x film effectively impedes the leakage of current at the FTO/hole transporting material (HTM) interface. Current–voltage curves, electrochemical impedance spectroscopy and open-circuit voltage decay are used to evaluate the function of TiO x compact layer in the solid-state solar cells. Results show that the best cell performance is observed in the cell with optimum compact layer thickness of 85 nm, which shows 814% increase in the power conversion efficiency (PCE) when compared with the bare cell. Thicker TiO x film suppresses the charge recombination more effectively, leading to longer electron lifetime of the solar cells. Nevertheless, higher resistance of the thicker TiO x film decreases its electron transport ability, thereby leading to lower PCE. Besides, compared to liquid-state solar cells, solid-state solar cells require thicker TiO x compact layer to block the electron loss and show larger increase of PCE (highest 27% enhancement in liquid-state solar cells with 85 nm TiO x layer), which corresponds to the much faster charge recombination and ~15 times lower electron-carrier lifetime in solid-state solar cell.

Four kinds of TiO2 electrodes with different porosities were prepared by adding different ratios of ethyl cellulous into a Dyesol 18-NRT paste. Higher polymer ratios contributed to the higher porosity of TiO2 films. All electrodes were spin-coated with spiro-OMeTAD and fabricated into solid-state dye-sensitized solar cells (ss-DSCs). This simple method allowed more spiro-OMeTAD penetrated into the more porous TiO2 films. This result demonstrated the pore-filling effect of hole transport materials on the photovoltaic performance of ss-DSCs. Photoluminescence and electrical impedance spectra measurements were introduced to investigate the dye regeneration, charge transport, and recombination kinetics of the solar cells. The increased pore filling of spiro-OMeTAD could enhance hole injection, hole transport, and recombination retardation, thus providing good charge collection efficiency and long recombination lifetime and resulting in the high short-circuit current density, open-circuit voltage, fill factor, and energy conversion efficiency of the solar cells. An efficiency enhancement of 34 % was obtained by using this method. However, further increasing the TiO2 porosity decreased the electron transport, thus causing a low charge collection and reducing cell performance.

A series of perovskite-based solar cells were fabricated wherein a compact layer (CL) of TiO 2 of varying thickness (0–390 nm) was introduced by spray pyrolysis deposition between fluorine-doped tin oxide (FTO) electrode and TiO 2 nanoparticle layer in perovskite-based solar cells. Investigations of the CL thickness-dependent current density–voltage ( J–V ) characteristics, dark current, and open circuit voltage ( V oc ) decays showed a similar trend for thickness dependence. A CL thickness of 90 nm afforded the perovskite-based solar cell with the maximum power conversion efficiency ( η , 3.17%). Furthermore, two additional devices, perovskite-based solar cell omitting hole transporting materials layer and cell without the TiO 2 nanoparticles, were designed and fabricated to study the influence of the CL thickness on different electron transport paths in perovskite-based solar cells. Solar cells devoid of TiO 2 nanoparticles, but with perovskite and organic hole-transport materials (HTMs), exhibited sustained improvement in photovoltaic performances with increase in the thickness of CL, which is in contrast to the behavior of classical perovskite-based solar cell and common solid state solar cell which showed optimal photovoltaic performances when the thickness of CL is 90 nm. These observations suggested that TiO 2 nanoparticles play a significant role in electron transport in perovskite-based solar cells.

Annealing is a route that has proven to be successful at enhancing the hole mobility of some hole transporting materials. Under this consideration, we systematically investigated the effect of annealing treatment on the spiro-OMeTAD and its corresponding solar cells by annealing the dye-sensitized TiO2 electrodes at 80 and 140 °C. Upon annealing, the crystallization and oxidation of spiro-OMeTAD enhanced, thereby favoring higher hole transfer and transport, ultimately leading to higher short-circuit current (Jsc). However, the annealed devices showed lower open-circuit voltage, which was due to the downshifting of TiO2 Fermi level as revealed by the transient photovoltage measurement. Results obtained in this study indicate the bis(trifluoromethylsulfonyl)imide (Li-TFSI) is responsible for the spiro-OMeTAD oxidization and TiO2 Fermi level reduction during the annealing. Further to be annealed at 140 °C, the 4-tert-butyl pyridine (tBP) evaporated to further down-shift the TiO2 Fermi level and dramatically reduce the Jsc, hence, the corresponded solar cell revealed the lowest efficiency. Typically, the standard temperature for thermal stress testing of solar cells in commercial applications is 85 °C. Therefore, it is highly imperative to have a better understanding of this phenomenon in order to achieve long-term stability of solid-state dye sensitized solar cells.

In this study, approximately 20 nm thick compact layers of TiO x with varied components are deposited by physical vapor deposition. The performance of these layers in solar cells is investigated. The TiO x compact layers consist of T1 (with Ti 0 , Ti 2+ , Ti 3+ , and Ti 4+ ), T2 (with Ti 3+ and Ti 4+ ), and T3 (with Ti 4+ ). Results show that the optimum compact layer is T1, which exhibits an approximately 61% enhancement in energy conversion efficiency compared with the bare cell. Mott–Schottky plots indicate that the carrier concentration decreases and the flatband becomes less negative with decreasing x , which consequently increases the likelihood of charge transfer from the nanoporous TiO 2 to the TiO x compact layers. Furthermore, a decrease in the x value of TiO x results in lower resistance. Voltage decay and electrical impedance spectrum (EIS) show that the electron-carrier lifetime and charge recombination reduction are improved the most by T1. Consequently, TiO x with smaller x works better as a compact layer. However, a solar cell with T2 shows weak enhancement of photovoltaic performance. Cyclic voltammetry and EIS illustrate that the low recombination blocking and high resistance of T2 may be a result of its large pore size and weak adhesion to fluorine-doped tin oxide glass.

We presented a distance-based detection method for visual quantification of mercury ions on a microfluidic paper-based analytical device (μPAD). Dithizone in NaOH solution was used as chromogenic reagent and deposited onto paper channel delimited by hydrophobic wax barrier. Reactions happened between mercury ions and dithizone to form an insoluble colored complex, producing colored precipitate on the paper channel. The length of colored precipitate could be readily measured using the printed ruler along each device. The length of precipitate increase linearly with the mercury concentrations, mercury in sample solution could be quantified by measuring the length of the colored precipitate. Being free of any electronic instruments, this method has the advantages of portability, ease of use, low cost and disposability. This presented method was used to detect mercury ions in a synthetic sample, demonstrating its potential in on-site and real time analysis.

The analysis of SAR images requires to reduce the speckle noise due to the coherent character of the radar signal. This noise is multiplicative, which often leads to logarithmically transform the modulus. A bias, which depends on the local homogeneity is introduced, and the noise is amplified. The minimum variance estimator leads to process the energy image instead of the modulus one for reducing this multiplicative noise. The proposed methods are based on a multiscale vision model for which the image is only described by its significant structural features on a set of scales. The multiscale analysis is performed by a redundant discrete wavelet transform, the a trous algorithm. We have determined the distribution law of the wavelet coefficient of the energy in the case of a statistically uniform image. This allows us to extract the significant wavelet coefficients, according to the noise. A filtering algorithm is derived by taking into account only these coefficients. This method is extended to a co-addition of SAR images. Taking into account the multiresolution support obtained from the thresholding in the wavelet transform space (WTS), the image is decomposed into a set of objects, by a 3D segmentation in WTS.

The analysis of SAR images requires in a first step to reduce the speckle noise which is due to the coherent character of the RADAR signal. The application of the minimum variance bound estimator leads to process the energy image instead of the amplitude one for the reduction of this multiplicative noise. The proposed analyzing methods are based on a multiscale vision model for which the image is only described by its significant structural features at a set of dyadic scales. The multiscale analysis is performed by a redundant discrete wavelet transform, the a trous algorithm. The filtering algorithm is interactive. At each step we compute the ratio between the observed energy image and the restored one. We detect at each scale the significant structures, by taking into account the exponential probability distribution function of the energy for the determination of the significant wavelet coefficients. The ratio is restored from its significant coefficients, and the restored image is updated. The iterations are stopped when any significant structure is detected in the ratio. Then, we are interested to extract and to analyze the contained objects. The multiscale analysis allows us an approach well adapted to diffused objects, without contrasted edges. An object is defined as a local maximum in the wavelet transform space (WTS). All the structures form a 3D connected set which is hierarchically organized. This set gives the description of an object in the WTS. The image of each object is restored y an inverse algorithm. The comparison between images taken at different epochs is done using the multiscale vision model. THat allows us to enhance the features at a given scale which have significantly varied. The correlation coefficients between the structures detected at each scale are far form the ones obtained between the pixel energy. For example, this method is very suitable to detect and to describe faint large scale variations.