Tunable Conductivity and Conduction Mechanism in a UV light activated electronic conductor

A tunable conductivity has been achieved by controllable substitution of a novel UV light activated electronic conductor. The transparent conducting oxide system H-doped Ca12-xMgxAl14O33 (x = 0; 0.1; 0.3; 0.5; 0.8; 1.0) presents a conductivity that is strongly dependent on the substitution level and temperature. Four-point dc-conductivity decreases with x from 0.26 S/cm (x = 0) to 0.106 S/cm (x = 1) at room temperature. At each composition the conductivity increases (reversibly with temperature) until a decomposition temperature is reached; above this value, the conductivity drops dramatically due to hydrogen recombination and loss. The observed conductivity behavior is consistent with the predictions of our first principles density functional calculations for the Mg-substituted system with x=0, 1 and 2. The Seebeck coefficient is essentially composition- and temperature-independent, the later suggesting the existence of an activated mobility associated with small polaron conduction. The optical gap measured remains constant near 2.6 eV while transparency increases with the substitution level, concomitant with a decrease in carrier content.Comment: Submitted for publicatio

Spectroscopic Analysis for the Identification of Loss Mechanisms in Back-Contact Perovskite Solar Cells

Back-contact perovskite solar cells offer a significant potential to reach high efficiency due to reduced parasitic absorption from the top surface. However, the currently reported efficiencies are considerably lower (&lt;10%) than planar perovskite solar cells (&gt;20%). Herein, back-contact perovskite solar cells are fabricated to study loss mechanisms that cause low device efficiency. This work spatially resolves the short-circuit current, open-circuit voltage, photoluminescence quantum yield, carrier lifetime, and external quantum efficiency of the devices. The results indicate that the front surface recombination, increased nonradiative recombination at hole contact layer/perovskite interface, and the extraction barriers are three main mechanisms limiting devices from achieving high efficiencies.</p

A comparison between skinfold callipers and ultrasound imaging for assessing body composition in recreationally active students

The measurement of skinfold thickness by means of skinfold callipers (SC) is a widely accepted method to assess subcutaneous fat thickness and percentage body fat (%BF). Ultrasound imaging (USI) is a more recent technology that is becoming accessible for the same application. The objective of this study was to compare measurements recorded by SC and USI for the assessment of subcutaneous fat thickness in order to estimate %BF. Thirty adults volunteered for the study. Body mass, stature and subcutaneous fat thickness for seven sites were measured. Strong (p0.05) difference between the %BF determined by the two methods (SC=19.5±6.4 %BF and USI = 19.0±6.3 %BF). However, levels of agreement indicated that the USI could over- or underestimate %BF by ±10%. This resulted in %BF estimation errors which are deemed too large from a clinical perspective. Additional studies are recommended to investigate the lack of agreement and bias highlighted between the two methods.http://www.tandfonline.com/loi/terg20am2016PhysiologyBiokinetics, Sport and Leisure Science

Associations between depression, lifestyle and brain structure:A longitudinal MRI study

Background: Depression has been associated with decreased regional grey matter volume, which might partly be explained by an unhealthier lifestyle in depressed individuals which has been ignored by most earlier studies. Also, the longitudinal nature of depression, lifestyle and brain structure associations is largely unknown. This study investigates the relationship of depression and lifestyle with brain structure cross-sectionally and longitudinally over up to 9 years. Methods: We used longitudinal structural MRI data of persons with depression and/or anxiety disorders and controls (Nunique participants = 347, Nobservations = 609). Cortical thickness of medial orbitofrontal cortex (mOFC), rostral anterior cingulate cortex (rACC) and hippocampal volume were derived using FreeSurfer. Using Generalized Estimating Equations, we investigated associations of depression and lifestyle (Body mass index (BMI), smoking, alcohol consumption, physical activity and sleep duration) with brain structure and change in brain structure over 2 (n = 179) and 9 years (n = 82). Results: Depression status (B = -.053, p = .002) and severity (B = -.002, p = .002) were negatively associated with rACC thickness. mOFC thickness was negatively associated with BMI (B = -.004, p < .001) and positively with moderate alcohol consumption (B = .030, p = .009). All associations were independent of each other. No associations were observed between (change in) depression, disease burden or lifestyle factors with brain change over time. Conclusions: Depressive symptoms and diagnosis were independently associated with thinner rACC, BMI with thinner mOFC, and moderate alcohol consumption with thicker mOFC. No longitudinal associations were observed, suggesting that regional grey matter alterations are a long-term consequence or vulnerability indicator for depression but not dynamically or progressively related to depression course trajectory

Impact of Polypharmacy on Health-Related Quality of Life in Dialysis Patients

INTRODUCTION: Dialysis patients are often prescribed a large number of medications to improve metabolic control and manage coexisting comorbidities. However, some studies suggest that a large number of medications could also detrimentally affect patients' health-related quality of life (HRQoL). Therefore, this study aims to provide insight in the association between the number of types of medications and HRQoL in dialysis patients. METHODS: A multicentre cohort study was conducted among dialysis patients from Dutch dialysis centres 3 months after initiation of dialysis as part of the ongoing prospective DOMESTICO study. The number of types of medications, defined as the number of concomitantly prescribed types of drugs, was obtained from electronic patient records. Primary outcome was HRQoL measured with the Physical Component Summary (PCS) score and Mental Component Summary (MCS) score (range 0–100) of the Short Form 12. Secondary outcomes were number of symptoms (range 0–30) measured with the Dialysis Symptoms Index and self-rated health (range 0–100) measured with the EuroQol-5D-5L. Data were analysed using linear regression and adjusted for possible confounders, including comorbidity. Analyses for MCS and number of symptoms were performed after categorizing patients in tertiles according to their number of medications because assumptions of linearity were violated for these outcomes. RESULTS: A total of 162 patients were included. Mean age of patients was 58 ± 17 years, 35% were female, and 80% underwent haemodialysis. The mean number of medications was 12.2 ± 4.5. Mean PCS and MCS were 36.6 ± 10.2 and 46.8 ± 10.0, respectively. The mean number of symptoms was 12.3 ± 6.9 and the mean self-rated health 60.1 ± 20.6. In adjusted analyses, PCS was 0.6 point lower for each additional medication (95% confidence interval [95% CI]: −0.9 to −0.2; p = 0.002). MCS was 4.9 point lower (95% CI: −8.8 to −1.0; p = 0.01) and 1.0 point lower (95% CI: −5.1–3.1; p = 0.63) for the highest and middle tertiles of medications, respectively, than for the lowest tertile. Patients in the highest tertile of medications reported 4.1 more symptoms than in the lowest tertile (95% CI: 1.5–6.6; p = 0.002), but no significant difference in the number of symptoms was observed between the middle and lowest tertiles. Self-rated health was 1.5 point lower for each medication (95% CI: −2.2 to −0.7; p < 0.001). DISCUSSION/CONCLUSION: After adjustment for comorbidity and other confounders, a higher number of medications were associated with a lower PCS, MCS, and self-rated health in dialysis patients and with more symptoms

Fractionation of Adipose Tissue Procedure With a Disposable One-Hole Fractionator

Background: Adipose tissue has been widely used in regenerative surgery for its therapeutic potential. This potential is often ascribed to the stromal vascular fraction (SVF), which can be mechanically isolated. Mechanical isolation results in an SVF that retains intact cell-cell communication including extracellular matrix and is therefore named tissue-SVF (tSVF). Objectives: The aim of this study was to evaluate a new disposable 1-hole fractionator for fractionation of adipose tissue (FAT), and compare this new device with the existing reusable 3-hole fractionator. Methods: The composition of tSVF obtained via the 1-hole fractionator was histologically and histochemically compared to unprocessed adipose tissue. The number of viable nuclear cells in tSVF obtained by the 1-hole and 3-hole fractionators as well as unprocessed adipose tissue were compared after enzymatic isolation and tested for colony-forming capacity. Flow cytometry was used to compare different cell compositions based on surface marker expression between tSVF isolated by the two types of fractionators. Results: Fractionation of adipose tissue with the 1-hole fractionator condenses vasculature and extracellular matrix by disrupting adipocytes. The number of viable nuclear cells in tSVF obtained with the two fractionators was comparable and significantly higher than unprocessed lipoaspirate. Furthermore, tSVF isolated by both fractionators showed similar cell compositions and comparable colony-forming capacities. Conclusions: FAT with a disposable 1-hole fractionator effectively isolates tSVF with a cell count and cell composition comparable to the fraction obtained with the 3-hole reusable fractionator. The disposable 1-hole fractionator, however, is safer and more user friendly

Structural evolution and skyrmionic phase diagram of the lacunar spinel GaMo4Se8

In the $AB_4Q_8$ lacunar spinels, the electronic structure is described on the basis of inter- and intra-cluster interactions of tetrahedral $B_4$ clusters, and tuning these can lead to myriad fascinating electronic and magnetic ground states. In this work, we employ magnetic measurements, synchrotron X-ray and neutron scattering, and first-principles electronic structure calculations to examine the coupling between structural and magnetic phase evolution in GaMo$_4$Se$_8$, including the emergence of a skyrmionic regime in the magnetic phase diagram. We show that the competition between two distinct Jahn-Teller distortions of the room temperature cubic $F\overline{4}3m$ structure leads to the coexistence of the ground state $R3m$ phase and a metastable $Imm2$ phase. The magnetic properties of these two phases are computationally shown to be very different, with the $Imm2$ phase exhibiting uniaxial ferromagnetism and the $R3m$ phase hosting a complex magnetic phase diagram including equilibrium N\'eel--type skyrmions stable from nearly $T$ = 28 K down to $T$ = 2 K, the lowest measured temperature. The large change in magnetic behavior induced by a small structural distortion reveals that GaMo$_4$Se$_8$ is an exciting candidate material for tuning unconventional magnetic properties $via$ mechanical means