Machine Learning Optimization of p-Type Transparent Conducting Films

p-Type transparent conducting materials (p-TCMs) are important components of optoelectronic devices including solar cells, photodetectors, displays, and flexible sensors. Cu-Zn-S thin films prepared by chemical bath deposition (CBD) can have both high transparency in the visible range (>80%) as well as excellent hole conductivity (>1000 S cm-1). However, the interplay between the deposition parameters in the CBD process (metal and sulfur precursor concentrations, temperature, pH, complexing agents, etc.) creates a multidimensional parameter space such that optimization for a specific application is challenging and time-consuming. Here we show that strategic design of experiment combined with machine learning (ML) allows for the efficient optimization of p-TCM performance. The approach is guided by a figure of merit (FOM) calculated from the film conductivity and optical transmission in the desired spectral range. A specific example is shown using two steps of optimization using a selected subset of four experimental CBD factors. The ML model is based on support vector regression employing a radial basis function as the kernel function. 10-fold cross-validation was performed to mitigate overfitting. After the first round of optimization, predicted areas in the parameter space with maximal FOMs were selected for a second round of optimization. Films with optimal FOMs were incorporated into heterojunction solar cells and transparent photodiodes. The optimization approach shown here will be generally applicable to any materials synthesis process with multiple parameters

Protective effect of nitric oxide against arsenic-induced oxidative damage in tall fescue leaves

Nitric oxide (NO) is a key molecule involved in many physiology processes. The effects of NO on alleviating arsenic-induced oxidative damage in tall fescue leaves were investigated. Arsenic (25 M) treatment induced significantly accumulation of reactive oxygen species (ROS) and led to serious lipid peroxidation in tall fescue leaves and the application of 100 M SNP before arsenic stress resulted in alleviated arsenic-induced electrolyte leakage and malondiadehyde (MDA) content in tall fescue leaves, the levels of hydrogen peroxide (H2O2) and superoxide radical (O2̅ ) were reduced as well. Moreover, the activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) increased in tall fescue leaves in presence of SNP under arsenic stress. This pattern was reversed by application of NO scavenger, 2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethy-limidazoline-1-oxyl-3-oxide (PTIO) before arsenic treatment. Pronounced increases in endogenous NO production was found in plants after exposure to arsenic stress. The results suggested that arsenic stress elevated endogenous NO level and that NO might act as a signaling molecule to enhance antioxidant enzyme activities, further protecting against injuries caused by arsenic toxicity

Genetic diversity and population structure of Caragana microphylla Lam. based on analysis of inter-simple sequence repeat markers

Caragana microphylla Lam. is a long-lived shrub species in the semi-arid, arid and desert regions. To determine the genetic diversity and population structure of C. microphylla Lam., 17 wild populations from the central and eastern part of Inner Mongolia were analyzed by inter-simple sequence repeat. 18 primers  produced 296 bands across a total of 510 individuals. A high percentage of polymorphic loci was observed at species level (PPB = 81.4%). Based on analysis of molecular variance, 74.99% of the genetic variation of C. microphylla Lam. was found within population, 7% difference between regions and 15.2% among collection  sites within regions. Cluster analyses showed that 17 populations are most arranged in the same cluster by  geographic location. An indirect estimate of the GST-derived Nm value (Nm = 1.8921) indicate that gene flow is high among 17 populations. No significant correlation (r2 = 0.13) between genetic and geographic distance was detected. Results of this study suggest that C. microphylla Lam. has a high genetic variability and potential as a source of variation for breeding programs.Key words: Inter-simple sequence repeat (ISSR), Caragana microphylla Lam., genetic structure

pH plays a role in the mode of action of trimethoprim on Escherichia coli

Metabolomics-based approaches were applied to understand interactions of trimethoprim with Escherichia coli K-12 at sub-minimum inhibitory concentrations (MIC≈0.2, 0.03 and 0.003 mg L-1). Trimethoprim inhibits dihydrofolate reductase and thereby is an indirect inhibitor of nucleic acid synthesis. Due to the basicity of trimethoprim, two pH levels (5 and 7) were selected which mimicked healthy urine pH. This also allowed investigation of the effect on bacterial metabolism when trimethoprim exists in different ionization states. UHPLC-MS was employed to detect trimethoprim molecules inside the bacterial cell and this showed that at pH 7 more of the drug was recovered compared to pH 5; this correlated with classical growth curve measurements. FT-IR spectroscopy was used to establish recovery of reproducible phenotypes under all 8 conditions (3 drug levels and control in 2 pH levels) and GC-MS was used to generate global metabolic profiles. In addition to finding direct mode-of-action effects where nucleotides were decreased at pH 7 with increasing trimethoprim levels, off-target pH-related effects were observed for many amino acids. Additionally, stress-related effects were observed where the osmoprotectant trehalose was higher at increased antibiotic levels at pH 7. This correlated with glucose and fructose consumption and increase in pyruvate-related products as well as lactate and alanine. Alanine is a known regulator of sugar metabolism and this increase may be to enhance sugar consumption and thus trehalose production. These results provide a wider view of the action of trimethoprim. Metabolomics indicated alternative metabolism areas to be investigated to further understand the off-target effects of trimethoprim

Acclimation of morphology and physiology in turf grass to low light environment: A review

This short review elucidated the significance of the research on acclimation of the morphology and physiology in turf grass to low light environment, the mechanism of physiological response and the photosynthetic regulation and control of turf grass to suit low light environment. We also discussed current research problems and provided insight into future relevant research.Key words: Low light, morphological change, physiological acclimation, regulation mechanism, turf grass

A Novel NFC Antenna for Metal Cover Smartphone Applications

© 2018 IEEE. A miniaturized dual-loop near field communication antenna of size 15 mm×25 mm is proposed for metal cover smartphone applications. By embedded it with a small rectangular slot of size 8 mm×16 mm loaded metal cover, the direction of the eddy current induced on metal cover will be the same with the current flow the on the dual loop NFC antenna coil. It's worth noting that the proposed NFC antenna design was certified by the Europay, Mastercard and Visa (EMV) test

Making a splash with water repellency

A 'splash' is usually heard when a solid body enters water at large velocity. This phenomena originates from the formation of an air cavity resulting from the complex transient dynamics of the free interface during the impact. The classical picture of impacts on free surfaces relies solely on fluid inertia, arguing that surface properties and viscous effects are negligible at sufficiently large velocities. In strong contrast to this large-scale hydrodynamic viewpoint, we demonstrate in this study that the wettability of the impacting body is a key factor in determining the degree of splashing. This unexpected result is illustrated in Fig.1: a large cavity is evident for an impacting hydrophobic sphere (1.b), contrasting with the hydrophilic sphere's impact under the very same conditions (1.a). This unforeseen fact is furthermore embodied in the dependence of the threshold velocity for air entrainment on the contact angle of the impacting body, as well as on the ratio between the surface tension and fluid viscosity, thereby defining a critical capillary velocity. As a paradigm, we show that superhydrophobic impacters make a big 'splash' for any impact velocity. This novel understanding provides a new perspective for impacts on free surfaces, and reveals that modifications of the detailed nature of the surface -- involving physico-chemical aspects at the nanometric scales -- provide an efficient and versatile strategy for controlling the water entry of solid bodies at high velocity.Comment: accepted for publication in Nature Physic

Cytosolic targeting factor AKR2A captures chloroplast outer membrane-localized client proteins at the ribosome during translation

In eukaryotic cells, organellar proteome biogenesis is pivotal for cellular function. Chloroplasts contain a complex proteome, the biogenesis of which includes post-translational import of nuclear-encoded proteins. However, the mechanisms determining when and how nascent chloroplast-targeted proteins are sorted in the cytosol are unknown. Here, we establish the timing and mode of interaction between ankyrin repeat-containing protein 2 (AKR2A), the cytosolic targeting factor of chloroplast outer membrane (COM) proteins, and its interacting partners during translation at the single-molecule level. The targeting signal of a nascent AKR2A client protein residing in the ribosomal exit tunnel induces AKR2A binding to ribosomal RPL23A. Subsequently, RPL23A-bound AKR2A binds to the targeting signal when it becomes exposed from ribosomes. Failure of AKR2A binding to RPL23A in planta severely disrupts protein targeting to the COM; thus, AKR2A-mediated targeting of COM proteins is coupled to their translation, which in turn is crucial for biogenesis of the entire chloroplast proteome.open1178Ysciescopu

Improving the effectiveness of energy savings measures at companies by means of a new baseline adjustment strategy

This paper discusses a strategy for establishing an energy consumption baseline for the effects of defining and applying new strategies to improve the effectiveness of energy savings measures. Through this analysis, the energy baseline is adjusted to the dynamics of a typical operation, reducing uncertainty about operating data when it is not possible to determine that a given energy consumption level is typical. The strategy enables focusing efforts on the points in the operation with greatest impact on energy efficiency as a function of frequency of operation