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https://www.readbyqxmd.com/read/29149603/structural-basis-of-mitochondrial-transcription-initiation
#1
Hauke S Hillen, Yaroslav I Morozov, Azadeh Sarfallah, Dmitry Temiakov, Patrick Cramer
Transcription in human mitochondria is driven by a single-subunit, factor-dependent RNA polymerase (mtRNAP). Despite its critical role in both expression and replication of the mitochondrial genome, transcription initiation by mtRNAP remains poorly understood. Here, we report crystal structures of human mitochondrial transcription initiation complexes assembled on both light and heavy strand promoters. The structures reveal how transcription factors TFAM and TFB2M assist mtRNAP to achieve promoter-dependent initiation...
November 16, 2017: Cell
https://www.readbyqxmd.com/read/29148717/raman-spectroscopy-of-single-light-absorbing-carbonaceous-particles-levitated-in-air-using-an-annular-laser-beam
#2
Masaru Uraoka, Keisuke Maegawa, Shoji Ishizaka
A laser trapping technique is a powerful means to investigate the physical and chemical properties of single aerosol particles in a non-contact manner. However, optical trapping of strongly light-absorbing particles such as black carbon or soot is quite difficult because the repulsive force caused by heat is orders of magnitude larger than the attractive force of radiation pressure. In this study, a laser trapping and Raman microspectroscopy system using an annular laser beam was constructed to achieve non-contact levitation of single light-absorbing particles in air...
November 17, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/29148404/other-autoinflammatory-disease-genes-in-an-fmf-prevalent-population-a-homozygous-mvk-mutation-and-a-novel-heterozygous-tnfrsf1a-mutation-in-two-different-turkish-families-with-clinical-fmf
#3
İlker Karacan, Serdal Uğurlu, Aslıhan Tolun, Eda Tahir Turanlı, Huri Özdoğan
OBJECTIVES: No MEFV mutations are detected in approximately 10% of the patients with clinical FMF in populations where the disease is highly prevalent. Causative mutations were searched in other genes in two such families with "MEFV negative clinical FMF". METHODS: Father and daughter of family A had attacks of fever, abdominal pain and AA amyloidosis. The two sibs of family B complained of febrile episodes with abdominal pain and arthritis. The patients were clinically investigated...
October 27, 2017: Clinical and Experimental Rheumatology
https://www.readbyqxmd.com/read/29147543/combining-the-catalytic-enantioselective-reaction-of-visible-light-generated-radicals-with-a-by-product-utilization-system
#4
Xiaoqiang Huang, Shipeng Luo, Olaf Burghaus, Richard D Webster, Klaus Harms, Eric Meggers
We report an unusual reaction design in which a chiral bis-cyclometalated rhodium(iii) complex enables the stereocontrolled chemistry of photo-generated carbon-centered radicals and at the same time catalyzes an enantioselective sulfonyl radical addition to an alkene. Specifically, employing inexpensive and readily available Hantzsch esters as the photoredox mediator, Rh-coordinated prochiral radicals generated by a selective photoinduced single electron reduction are trapped by allyl sulfones in a highly stereocontrolled fashion, providing radical allylation products with up to 97% ee...
October 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/29144755/holographic-plasmonic-nano-tweezers-for-dynamic-trapping-and-manipulation
#5
Preston R Huft, Joshua D Kolbow, Jonathan T Thweatt, Nathan C Lindquist
We demonstrate dynamic trapping and manipulation of nanoparticles with plasmonic holograms. By tailoring the illumination pattern of an incident light beam with a computer-controlled spatial light modulator, constructive and destructive interference of plasmon waves create a focused hotspot that can be moved across a surface. Specifically, a computer-generated hologram illuminating the perimeter of a silver Bull's Eye nanostructure generates surface plasmons that propagate towards the center. Shifting the phase of the plasmon waves as a function of space gives complete control over the location of the focus...
November 16, 2017: Nano Letters
https://www.readbyqxmd.com/read/29144389/effects-of-infrared-optical-trapping-on-saccharomyces-cerevisiae-in-a-microfluidic-system
#6
Zdeněk Pilát, Alexandr Jonáš, Jan Ježek, Pavel Zemánek
Baker's yeast (Saccharomyces cerevisiae) represents a very popular single-celled eukaryotic model organism which has been studied extensively by various methods and whose genome has been completely sequenced. It was also among the first living organisms that were manipulated by optical tweezers and it is currently a frequent subject of optical micromanipulation experiments. We built a microfluidic system for optical trapping experiments with individual cells and used it for the assessment of cell tolerance to phototoxic stress...
November 16, 2017: Sensors
https://www.readbyqxmd.com/read/29144282/substrate-effects-in-high-gain-low-operating-voltage-snse2-photoconductor
#7
Krishna Murali, Sangeeth Kallatt, Kausik Majumdar
High gain photoconductive devices find wide spread applications in low intensity light detection. Ultra-thin layered materials have recently attracted a lot of attention from researchers in this regard. However, in general, a large operating voltage is required to obtain large responsivity in these devices. In addition, the characteristics are often confounded by substrate induced trap effects. Here we report multi-layer SnSe2 based photoconductive devices using two different structures: (1) SiO2 substrate supported interdigitated electrode (IDE), and (2) suspended channel...
November 16, 2017: Nanotechnology
https://www.readbyqxmd.com/read/29140080/vapor-assisted-solution-approach-for-high-quality-perovskite-ch3nh3pbbr3-thin-films-for-high-performance-green-light-emitting-diodes-applications
#8
Huifang Ji, Zhifeng Shi, Xuguang Sun, Ying Li, Sen Li, Lingzhi Lei, Di Wu, Tingting Xu, Xinjian Li, Guotong Du
Vapor-assisted solution method was developed to prepare the high-quality organic-inorganic halide perovskite CH3NH3PbBr3 (MAPbBr3) thin films. We detailedly investigated the effect of evaporation time and temperature of MABr powder on the microstructure, crystallinity and optical characterizations of MAPbBr3 thin films, and a controllable morphology evolution with varying surface coverage was observed. Temperature-dependent and time-resolved photoluminescence (PL) measurements were carried out to investigate the optical transition mechanisms and carrier recombination dynamics of MAPbBr3 thin films...
November 15, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29138818/%C3%AE-%C3%A2-ecdysterone-promotes-autophagy-and-inhibits-apoptosis-in-osteoporotic-rats
#9
Yang-Hua Tang, Zhen-Shuang Yue, Da-Wei Xin, Lin-Ru Zeng, Zhen-Fei Xiong, Zhong-Qing Hu, Can-Da Xu
Osteoporosis is an aging process of skeletal tissues with characteristics of reductions in bone mass and microarchitectural deterioration of bone tissue. The present study aimed to investigate the effects of glucocorticoid‑induced osteoporosis on osteoblasts and to examine the roles of β‑ecdysterone (β‑Ecd) involved. In the present study, an in vivo model of osteoporosis was established through the subcutaneous implantation of prednisolone (PRED) into Sprague‑Dawley rats, with or without a subcutaneous injection of β‑Ecd (5 or 10 mg/kg body weight)...
November 14, 2017: Molecular Medicine Reports
https://www.readbyqxmd.com/read/29138443/local-reasons-to-give-globally-identity-extension-and-global-cooperation
#10
Nancy R Buchan, Sophia Soyoung Jeong, A K Ward
Recent political events across the world suggest a retrenchment from globalization and a possible increase in parochialism. This inward-looking threat from parochialism occurs just as the global community faces growing challenges that require trans-national cooperation. In this research, we question if strong identification with an in-group necessarily leads to parochialism and ultimately is detrimental to global cooperation. Building on research on global social identification, we explore whether strong local identification can expand in inclusiveness to global identification, and among whom this is likely to happen...
November 14, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29135473/controllable-nanoscale-inverted-pyramids-for-high-efficient-quasi-omnidirectional-crystalline-silicon-solar-cells
#11
Haiyuan Xu, Sihua Zhong, Yufeng Zhuang, Wenzhong Shen
Nanoscale inverted pyramid structures (NIPs) have always been regarded as one of the most paramount light management schemes to achieve the extraordinary performance in various devices, especially in solar cells, due to their outstanding antireflection ability with relative lower surface enhancement ratio. However, the current approaches to fabricating the NIPs are complicated and not cost-effective for the massive cell production in the photovoltaic industry. Here, controllable NIPs are fabricated on crystalline silicon (c-Si) wafers by Ag catalyzed chemical etching and alkaline modification, which is a preferable all-solution-processed method...
November 14, 2017: Nanotechnology
https://www.readbyqxmd.com/read/29131180/comparison-of-photoemission-characteristics-between-square-and-circular-wire-array-gaas-photocathodes
#12
Wenjuan Deng, Xincun Peng, Jijun Zou, Weilu Wang, Yun Liu, Tao Zhang, Yijun Zhang, Daoli Zhang
Two types of negative electron affinity gallium arsenide (GaAs) wire array photocathodes were fabricated by reactive ion etching and inductively coupled plasma etching of bulk GaAs material. High density GaAs wire arrays with high periodicity and good morphology were verified using scanning electron microscopy, and photoluminescence spectra confirmed the wire arrays had good crystalline quality. Reflection spectra showed that circular GaAs wire arrays had superior light trapping compared with square ones. However, after Cs/O activation, the square GaAs wire array photocathodes showed enhanced spectral response...
November 10, 2017: Applied Optics
https://www.readbyqxmd.com/read/29128751/a-new-silver-metaniobate-semiconductor-of-ag0-5la0-5nb2o6-with-defect-perovskite-structure
#13
Longqing Mi, Yongyi Feng, Lei Cao, Mingqiang Xue, Yanlin Huang, Lin Qin, Hyo Jin Seo
Silver-containing lanthanum metaniobate Ag0.5La0.5Nb2O6 nanoparticles were synthesized by sol-gel polymerized complex method. A typical defect-perovskite structure was confirmed by XRD Rietveld refinements. The surface characteristics of the sample were tested by SEM, TEM and EDS measurements. SEM and TEM show that the sample presents ball-like particles with the diameters of 100nm to 400nm. The sample shows both self-activated luminescence and photocatalytic activities. Ag0.5La0.5Nb2O6 has a direct transition with band energy of 2...
November 3, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/29125763/benzyl-alcohol-treated-ch3nh3pbbr3-nanocrystals-exhibiting-high-luminescence-stability-and-ultralow-amplified-spontaneous-emission-thresholds
#14
Sjoerd A Veldhuis, Yong Kang Eugene Tay, Annalisa Bruno, Sai S H Dintakurti, Saikat Bhaumik, Subas Kumar Muduli, Mingjie Li, Nripan Mathews, Tze Chien Sum, Subodh G Mhaisalkar
We report the high yield synthesis of about 11 nm sized CH3NH3PbBr3 nanocrystals with near-unity photoluminescence quantum yield. The nanocrystals are formed in the presence of surface-binding ligands through their direct precipitation in a benzyl alcohol/toluene phase. The benzyl alcohol plays a pivotal role in steering the surface ligands binding motifs on the NC surface, resulting in enhanced surface-trap passivation and near-unity PLQY values. We further demonstrate that thin films from purified CH3NH3PbBr3 nanocrystals are stable >4 months in air, exhibit high optical gain (about 520 cm(-1)), and display stable, ultralow amplified spontaneous emission thresholds of 13...
November 14, 2017: Nano Letters
https://www.readbyqxmd.com/read/29125720/charge-transfer-from-carbon-nanotubes-to-silicon-in-flexible-carbon-nanotube-silicon-solar-cells
#15
Xiaokai Li, Marina Mariano, Lyndsey McMillon-Brown, Jing-Shun Huang, Matthew Y Sfeir, Mark A Reed, Yeonwoong Jung, André D Taylor
Mechanical fragility and insufficient light absorption are two major challenges for thin flexible crystalline Si-based solar cells. Flexible hybrid single-walled carbon nanotube (SWNT)/Si solar cells are demonstrated by applying scalable room-temperature processes for the fabrication of solar-cell components (e.g., preparation of SWNT thin films and SWNT/Si p-n junctions). The flexible SWNT/Si solar cells present an intrinsic efficiency ≈7.5% without any additional light-trapping structures. By using these solar cells as model systems, the charge transport mechanisms at the SWNT/Si interface are investigated using femtosecond transient absorption...
November 10, 2017: Small
https://www.readbyqxmd.com/read/29125252/the-distribution-of-mosquitoes-across-an-altitudinal-gradient-in-the-galapagos-islands
#16
Samoa Asigau, Daniel A Hartman, Jenni M Higashiguchi, Patricia G Parker
An avian malaria parasite (genus Plasmodium) has been detected consistently in the Galapagos Penguin (Spheniscus mendiculus) and less frequently in some passerines. We sampled three resident mosquito species (Aedes taeniorhynchus, Culex quinquefasciatus, and Aedes aegypti) using CDC light and gravid traps on three islands in 2012, 2013, and 2014. We sampled along altitudinal gradients to ask whether there are mosquito-free refugia at higher elevations as there are in Hawaii. We captured both Ae. taeniorhynchus and Cx...
December 2017: Journal of Vector Ecology: Journal of the Society for Vector Ecology
https://www.readbyqxmd.com/read/29124928/contact-selectivity-engineering-in-2-%C3%AE-m-thick-ultrathin-c-si-solar-cell-using-transition-metal-oxides-achieving-efficiency-of-10-8
#17
Muyu Xue, Raisul Islam, Andrew C Meng, Zheng Lyu, Ching-Ying Lu, Christian Tae, Michael R Braun, Kai Zang, Paul C McIntyre, Theodore I Kamins, Krishna C Saraswat, James S Harris
In this paper, the integration of metal oxides as carrier-selective contacts for ultra-thin crystalline silicon (c-Si) solar cells is demonstrated which results in ~13% relative improvement in efficiency. The improvement in efficiency originates from the suppression of the contact recombination current due to the band offset asymmetry of these oxides with Si. First, an ultra-thin c-Si solar cell having a total thickness of 2 μm is shown having >10% efficiency without any light trapping scheme. This is achieved by the integration of nickel oxide (NiOx) as a hole-selective contact interlayer material, which has a low valence band offset and high conduction band offset with Si...
November 10, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29124921/effect-of-rubidium-incorporation-on-the-structural-electrical-and-photovoltaic-properties-of-methylammonium-lead-iodide-based-perovskite-solar-cells
#18
Ik Jae Park, Seongrok Seo, Min Ah Park, Sangwook Lee, Dong Hoe Kim, Kai Zhu, Hyunjung Shin, Jin Young Kim
We report the electrical properties of rubidium-incorporated methylammonium lead iodide ((RbxMA1-x)PbI3) films and the photovoltaic performance of (RbxMA1-x)PbI3 film-based p-i-n-type perovskite solar cells (PSCs). The incorporation of a small amount of Rb(+) (x=0.05) increases both the open circuit voltage (Voc) and the short circuit photocurrent density (Jsc) of the PSCs, leading to an improved power conversion efficiency (PCE). However, a high fraction of Rb(+) incorporation (x=0.1 and 0.2) decreases the Jsc and thus the PCE, which is attributed to the phase segregation of the single tetragonal perovskite phase to a MA-rich tetragonal perovskite phase and a RbPbI3 orthorhombic phase at high Rb fractions...
November 10, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29122717/synthesis-and-characterization-of-methyl-pyrazolone-functionalized-magnetic-chitosan-composite-for-visible-light-photocatalytic-degradation-of-methylene-blue
#19
N A Abdelwahab, E M H Morsy
TiO2/Fe3O4, TiO2/Fe3O4/chitosan and Methylpyrazolone functionalized TiO2/Fe3O4/chitosan (MPyTMChi) were successfully prepared. The chemical structure of the prepared materials was confirmed by FT-IR spectra, XRD, SEM and TEM. BET surface area increased from 2.4 to 3.1m(2)/g, Eg decreased from 2.58 to 2.25eV and more quenching of PL emission spectra was observed upon functionalization of TMChi by MPy. Moreover, high Ti and oxygen percentages were detected by EDX. Magnetization value (Ms) reached 21 emu.g(-1) for MPyTMChi...
November 6, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/29122177/ascospore-release-in-apple-scab-underlies-infrared-sensation
#20
Katja Ehlert, Meike Piepenbring, Andreas Kollar
The agent of apple scab disease (Venturia inaequalis) is the most common pathogen in apple cultivation. Its ascospores are released in spring, mainly during daylight hours and triggered by rain events. To investigate the causes of diurnal rhythm of ascospore dissemination of the apple scab fungus ascospore releases were examined continuously with spore traps in the orchard and with laboratory assays. One of the spore traps was illuminated at night with different light sources in each year during 2011-2015. The laboratory assays were performed with different light sources with varying wavelengths and intensities...
December 2017: Fungal Biology
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