High-Efficiency 6′′ Multicrystalline Black Solar Cells Based on Metal-Nanoparticle-Assisted Chemical Etching

Multicrystalline silicon (mc-Si) photovoltaic (PV) solar cells with nanoscale surface texturing by metal-nanoparticle-assisted etching are proposed to achieve high power efficiency. The investigation of average nanorod lengths from 100 nm to 1 μm reveals that the Si wafer decorated with 100 nm thick nanorods has optical reflection of 9.5% inferior than the one with 1 μm thick nanorods (2%). However, the short nanorods improve the doping uniformity and effectively decrease metal contact resistance. After surface passivation using the hydrogenated SiO[subscript 2]/SiN[subscript x] (5 nm/50 nm) stack, the minority carrier lifetime substantially increases from 1.8 to 7.2 μs for the 100 nm-thick nanorod solar cell to achieve the high power efficiency of 16.38%, compared with 1 μm thick nanorod solar cell with 11.87%.National Science Council of Taiwan (project 100-2120-M-007-011-CC2

SCFKMD Controls Cytokinin Signaling by Regulating the Degradation of Type-B Response Regulators

Cytokinins are plant hormones that play critical roles in growth and development. In Arabidopsis, the transcriptional response to cytokinin is regulated by action of type-B Arabidopsis response regulators (ARRs). Although central elements in the cytokinin signal transduction pathway have been identified, mechanisms controlling output remain to be elucidated. Here we demonstrate that a family of F-box proteins, called the kiss me deadly (KMD) family, targets type-B ARR proteins for degradation. KMD proteins form an S-phase kinase-associated PROTEIN1 (SKP1)/Cullin/F-box protein (SCF) E3 ubiquitin ligase complex and directly interact with type-B ARR proteins. Loss-of-function KMD mutants stabilize type-B ARRs and exhibit an enhanced cytokinin response. In contrast, plants with elevated KMD expression destabilize type-B ARR proteins leading to cytokinin insensitivity. Our results support a model in which an SCF(KMD) complex negatively regulates cytokinin responses by controlling levels of a key family of transcription factors

Calibration of Built-in Accelerometer Using a Commercially Available Smartphone

Wearable trackers that detect sleep offer users a way to track their sleep quality and patterns without the use of expensive equipment. Few studies have tested the validity of these trackers on sleep measure. PURPOSE: To examine the validity of the Actigraph GT9X (AG), SenseWear Mini Armband (SW), Basis Peak (BP), Fitbit Charge HR (FB), Jawbone UP3 (JU), and Garmin Vivosmart (GV) for estimating sleep variables as compared with a sleep diary. METHODS: 78 healthy individuals participated in the study. Group 1 (n= 38) and wore the AG, SW, BP, and FB or Group 2 (n = 40) and wore the AG, JU, and GV. Monitors were worn on the non-dominant arm for 3 nights and a sleep log was completed. Sleep variables were total sleep time (TST), time in bed (TIB), sleep efficiency (SE), and wake after sleep onset (WASO). Pearson correlation, mean absolute percentage errors (MAPE), equivalence testing, Bland-Altman plots, and ANOVA were used to assess validity compared with the diary. RESULTS: Overall, monitors that showed the greatest correlation with the sleep diary for TST were the JU and FB (effect size= 0.09 and 0.23, respectively). The greatest correlation with the sleep diary for TIB was seen with the SW, GV, and JU (effect size= 0.09, 0.16, and 0.07, respectively). SE and WASO showed very poor correlation with the log. Measures for equivalence testing confirmed the success of the JU, SW, FB, and GV for measureing TIB and TST. CONCLUSION: The FB, SW, JU, and GV could be valid measure of TST and TIB. The monitors are not valid regarding wake times during sleep. Further research is needed to validate these monitors with polysomnography

Optical Investigations of Charge Gap in Orbital Ordered La1/2Sr3/2MnO4

Temperature and polarization dependent electronic structure of La1/2Sr3/2MnO4 were investigated by optical conductivity analyses. With decreasing temperature, for E//ab, a broad mid-infrared (MIR) peak of La1/2Sr3/2MnO4 becomes narrower and moves to the higher frequency, while that of Nd1/2Sr3/2MnO4 nearly temperature independent. We showed that the MIR peak in La1/2Sr3/2MnO4 originates from orbital ordering associated with CE-type magnetic ordering and that the Jahn-Teller distortion has a significant influence on the width and the position of the MIR peak.Comment: 10 pages, 4 figure

Instantons of M(atrix) Theory in PP-Wave Background

M(atrix) theory in PP-wave background possesses a discrete set of classical vacua, all of which preserves 16 supersymmetry and interpretable as collection of giant gravitons. We find Euclidean instanton solutions that interpolate between them, and analyze their properties. Supersymmetry prevents direct mixing between different vacua but still allows effect of instanton to show up in higher order effective interactions, such as analog of v^4 interaction of flat space effective theory. An explicit construction of zero modes is performed, and Goldstone zero modes, bosonic and fermionic, are identified. We further generalize this to massive M(atrix) theory that includes fundamental hypermultiplets, corresponding to insertion of longitudinal fivebranes in the background. After a brief comparison to their counterpart in AdS\times S, we close with a summary.Comment: 25 pages, LaTeX, references added, section 5 update

Generation of functional cardiomyocytes from the synoviocytes of patients with rheumatoid arthritis via induced pluripotent stem cells

Cardiovascular disease is a leading cause of morbidity in rheumatoid arthritis (RA) patients. This study aimed to generate and characterise cardiomyocytes from induced pluripotent stem cells (iPSCs) of RA patients. Fibroblast-like synoviocytes (FLSs) from patients with RA and osteoarthritis (OA) were successfully reprogrammed into RA-iPSCs and OA-iPSCs, respectively. The pluripotency of iPSCs was confirmed by quantitative reverse transcription-polymerase chain reaction and immunofluorescence staining. Established iPSCs were differentiated into cardiomyocytes using a small molecule-based monolayer differentiation protocol. Within 12 days of cardiac differentiation from patient-specific and control-iPSCs, spontaneously beating cardiomyocytes (iPSC-CMs) were observed. All iPSC-CMs exhibited a reliable sarcomeric structure stained with antibodies against cardiac markers and similar expression profiles of cardiac-specific genes. Intracellular calcium signalling was recorded to compare calcium-handling properties among cardiomyocytes differentiated from the three groups of iPSCs. RA-iPSC-CMs had a lower amplitude and a shorter duration of calcium transients than the control groups. Peak tangential stress and the maximum contractile rate were also decreased in RA-iPSC-CMs, suggesting that contractility was reduced. This study demonstrates the successful generation of functional cardiomyocytes from pathogenic synovial cells in RA patients through iPSC reprogramming. Research using RA-iPSC-CMs might provide an opportunity to investigate the pathophysiology of cardiac involvement in RA

Application of a non-halogenated solvent, methyl ethyl ketone (MEK) for recovery of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(HB-co-HV)] from bacterial cells

Conventional solvent-based methods are still the most practical approaches for recovery of polyhydroxyalkanoate (PHA) polymer from cellular biomass, even though potential alternatives exist, including chemical, mechanical, and enzymatic methods. It is still necessary, however, to avoid dangerous and environmentally unfriendly solvents (e.g., chloroform and dichloromethane) in the polymer recovery process. In the work presented here, we applied various solvent systems to recover PHA from Ralstonia eutropha and recombinant Escherichia coli cells. It was demonstrated that methyl ethyl ketone (MEK) is a promising solvent for PHA recovery from bacterial cells, particularly for the copolymer poly(hydroxybutyrate-cohydroxyvalerate) [P(HB-co-HV)], exhibiting > 90% polymer recovery. Even though MEK did not solubilize PHAs to the same extent as chloroform, it can recover a comparable amount of polymer because of its processing advantages, such as the low viscosity of the MEK/PHA solution, and the lower density of MEK as compared to cellular components. MEK was found to be the best alternative, non-halogenated solvent among examined candidates for recovery of P(HB-co-HV) from cells. The MEK treatment of PHAcontaining cells further allowed us to eliminate several costly and lengthy steps in the extraction process, such as cell lysis, centrifugation, and filtration.Korea (South). Ministry of Education (Basic Science Research Program through the National Research Foundation of Korea (NRF- 2013R1A1A2A10004690))Korea Polar Research Institute (PE14030

Thermal effects on atomic friction

We model friction acting on the tip of an atomic force microscope as it is dragged across a surface at non-zero temperatures. We find that stick-slip motion occurs and that the average frictional force follows $|\ln v|^{2/3}$, where $v$ is the tip velocity. This compares well to recent experimental work (Gnecco et al, PRL 84, 1172), permitting the quantitative extraction of all microscopic parameters. We calculate the scaled form of the average frictional force's dependence on both temperature and tip speed as well as the form of the friction-force distribution function.Comment: Accepted for publication, Physical Review Letter