Three-dimensional photoluminescence imaging of threading dislocations in GaN by sub-band optical excitation.

GaN is rapidly gaining attention for implementation in power electronics but is still impacted by its high density of threading dislocations (TDs), which have been shown to facilitate current leakage through devices limiting their performance and reliability. Here, we discuss a novel implementation of photoluminescence (PL) imaging to study TDs in regions within vertically structured p-i-n GaN (PIN) diodes consisting of metalorganic chemical vapor deposition (MOCVD) epitaxial layers grown on ammonothermal GaN (am-GaN) substrates. PL imaging with a sub-bandgap excitation energy (3.

Relationship between serum prealbumin level and prognosis of community-acquired bacterial meningitis in adults: a retrospective cohort study.

Background: Low serum prealbumin levels have been identified as a predictor of infectious complication in critically ill patients. However, the association in patients with Community-acquired bacterial meningitis (CABM) remains unclear. The aim of this study is to investigate the relationship of prealbumin and the poor outcome of CABM through a retrospective cohort study.

Weighted gene coexpression network analysis and machine learning for the determination of tfh cell and B cell infiltrating biomarkers in thymoma-associated myasthenia gravis.

Patients with thymoma (THYM)-associated myasthenia gravis (MG) typically have a poor prognosis and recurring illness. This study aimed to discover important biomarkers associated with immune cell infiltration and THYM-associated MG (THYM-MG) development. Gene expression microarray data were downloaded from The Cancer Genome Atlas website (TCGA) and Gene Expression Omnibus (GEO).

α-Tertiary Primary Amine Synthesis via Photocatalytic C(sp)-H Aminoalkylation.

Facile access to sterically hindered α-tertiary primary amines via photocatalytic radical coupling of native C(sp)-H substrates with -unsubstituted ketimines is reported. LiBr was used as a hydrogen atom transfer reagent to cleave C(sp)-H bonds to get alkyl radicals. The in situ-generated HBr can then serve as a Bronsted acid to activate -unsubstituted ketimines readily for single-electron reduction to deliver α-amino radicals.

Identification, evolution and expression analyses of the whole genome-wide PEBP gene family in Brassica napus L.

Background: With the release of genomic data for B.rapa, B.oleracea, and B.

Three-component reductive conjugate addition/aldol tandem reaction enabled by nickel/photoredox dual catalysis.

A three-component reductive cross-coupling of aryl halides, aldehydes, and alkenes by nickel/photoredox dual catalysis is disclosed. The key to success for this tandem transformation is to identify α-silylamine as a unique organic reductant, which releases silylium ions instead of protons to prevent unwanted protonation processes, and meanwhile serves as Lewis acid to activate aldehydes . This dual catalytic protocol completes a traditional conjugate addition/aldol sequence that eliminates the requirement of organometallic reagents and metal-based reductants, thus providing a mild synthetic route to highly valuable β-hydroxyl carbonyl compounds with contiguous 1,2-stereocenters.

Multi-functional topology optimization of veins.

The growth and development of biological tissues and organs strongly depend on the requirements of their multiple functions. Plant veins yield efficient nutrient transport and withstand various external loads. , a tropical species of the Nymphaeaceae family of water lilies, has evolved a network of three-dimensional and rugged veins, which yields a superior load-bearing capacity.

From Esters to Ketones via a Photoredox-Assisted Reductive Acyl Cross-Coupling Strategy.

A method was developed for ketone synthesis via a photoredox-assisted reductive acyl cross-coupling (PARAC) using a nickel/photoredox dual-catalyzed cross-electrophile coupling of two different carboxylic acid esters. A variety of aryl, 1°, 2°, 3°-alkyl 2-pyridyl esters can act as acyl electrophiles while N-(acyloxy)phthalimides (NHPI esters) act as 1°, 2°, 3°-radical precursors. Our PARAC strategy provides an alternative and reliable way to synthesize various sterically congested 3°-3°, 3°-2°, and aryl-3° ketones under mild and highly unified conditions, which have been otherwise difficult to access.

Thermal Conductivity of β-Phase GaO and (AlGa)O Heteroepitaxial Thin Films.

Heteroepitaxy of β-phase gallium oxide (β-GaO) thin films on foreign substrates shows promise for the development of next-generation deep ultraviolet solar blind photodetectors and power electronic devices. In this work, the influences of the film thickness and crystallinity on the thermal conductivity of (2̅01)-oriented β-GaO heteroepitaxial thin films were investigated. Unintentionally doped β-GaO thin films were grown on -plane sapphire substrates with off-axis angles of 0° and 6° toward ⟨112̅0⟩ via metal-organic vapor phase epitaxy (MOVPE) and low-pressure chemical vapor deposition.

Iridoid compounds from the aerial parts of Franch. with cytotoxic activity.

One new secoiridoid compound swertiamarin B (), along with a known compound lytanthosalin (), were isolated from ethanol extract of the aerial parts of . Their structures were elucidated by the detailed analysis of comprehensive spectroscopic data. All compounds were first isolated from the genus.

Piezo1 regulates migration and invasion of breast cancer cells via modulating cell mechanobiological properties.

Cell migration and invasion are two essential processes during cancer metastasis. Increasing evidence has shown that the Piezo1 channel is involved in mediating cell migration and invasion in some types of cancers. However, the role of Piezo1 in the breast cancer and its underlying mechanisms have not been clarified yet.

Quantitative defect analysis in MOCVD GaN-on-GaN using cathodoluminescence.

Cathodoluminescence (CL) is used as a quantitative characterization technique to probe impurities at the metal-organic chemical vapor deposition (MOCVD) grown GaN-on-GaN homoepitaxial interfaces. CL intensity contrast shows a strong correlation with the interfacial impurity concentrations. Based on the analysis of recombination mechanisms of electron beam induced non-equilibrium carriers, an analytical model is proposed to quantitatively determine the impurity concentrations from CL intensity.

A function of fascin1 in the colony formation of mouse embryonic stem cells.

Fascin1 is known to participate in the migration of cancer cells by binding to actin filaments. Recent studies evidenced that fascin1 also modulates processes such as the tumorigenesis and maintenance of pluripotency genes in cancer stem cells. However, the function of fascin1 in embryonic stem cells remains unclear.

Improved Prediction of Aqueous Solubility of Novel Compounds by Going Deeper With Deep Learning.

Aqueous solubility is an important physicochemical property of compounds in anti-cancer drug discovery. Artificial intelligence solubility prediction tools have scored impressive performances by employing regression, machine learning, and deep learning methods. The reported performances vary significantly partly because of the different datasets used.

Discontinued Drugs for the Treatment of Cardiovascular Disease from 2016 to 2018.

Cardiovascular drug research and development (R&D) has been in active state and continuously attracts attention from the pharmaceutical industry. However, only one individual drug can eventually reach the market from about the 10,000 compounds tested. It would be useful to learn from these failures when developing better strategies for the future.

Natural Silkworm Cocoon Composites with High Strength and Stiffness Constructed in Confined Cocooning Space.

In this study, using round paper tubes (PTs) and rectangular cardboard boxes (CBs) as external constraints to control the size of the cocooning space, we fabricated a series of modified silkworm cocoons (PT cocoons and CB cocoons). Their microstructures, morphologies, compositions, and mechanical properties were characterized and compared with normal silkworm cocoons. These two kinds of modified silkworm cocoons exhibit dense and homogeneous layer structures.

Effect of Different Additives in Diets on Secondary Structure, Thermal and Mechanical Properties of Silkworm Silk.

In this study, eight types of materials including nanoparticles (Cu and CaCO₃), metallic ions (Ca and Cu), and amino acid substances (serine, tyrosine, sericin amino acid, and fibroin amino acid) were used as additives in silkworm diets to obtain modified silk fiber composites. The results indicate that tyrosine and fibroin amino acids significantly increase potassium content in silk fibers and induce the transformation of α-helices and random coils to -sheet structures, resulting in higher crystallinities and better mechanical properties. However, the other additives-modified silk fibers show a decrease in -sheet contents and a slight increase or even decrease in tensile strengths.

Formal [7 + 2] Cycloaddition of Arynes with N-Vinyl-α,β-Unsaturated Nitrones: Synthesis of Benzoxazonines and Their N-O Bond Cleavage.

Various benzoxazonines were synthesized through a formal [7 + 2] cycloaddition of arynes with N-vinyl-α,β-unsaturated nitrones under mild conditions. Controllable N-O bond cleavage of benzoxazonines afforded polysubstituted pyrrole-tethered benzopyrans and acyclic ketone-substituted phenols in moderate to good yields. Further transformations provided a facile approach to access useful building blocks with specific stereoselectivity.

Silk fibroin peptide suppresses proliferation and induces apoptosis and cell cycle arrest in human lung cancer cells.

Silkworm cocoon was recorded to cure carbuncle in the Compendium of Materia Medica. Previous studies have demonstrated that the supplemental silk protein sericin exhibits anticancer activity. In the present study, we investigated the effects of silk fibroin peptide (SFP) extracted from silkworm cocoons against human lung cancer cells in vitro and in vivo and its possible anticancer mechanisms.

Swertia mussotii extracts induce mitochondria-dependent apoptosis in gastric cancer cells.

Swertia mussotii (Gentianaceae) is a traditional Chinese medicinal plant grown in the Qinghai-Tibet Plateau. Three fractions from S. mussotii extract, named SWF50, SWF 70 and SWF100, were screened for in vitro anti-proliferative activity on two gastric cancer cell lines, MGC-803 and BGC-823 cells using MTT assay.

Synergistic adhesion mechanisms of spider capture silk.

It is well known that capture silk, the main sticky component of the orb web of a spider, plays an important role in the spider's ability to capture prey via adhesion. However, the detailed mechanism with which the spider achieves its unparalleled high-adhesion performance remains elusive. In this work, we combine experiments and theoretical analysis to investigate the adhesion mechanisms of spider silk.

Tuning charge carrier transport and optical birefringence in liquid-crystalline thin films: A new design space for organic light-emitting diodes.

Liquid-crystalline organic semiconductors exhibit unique properties that make them highly interesting for organic optoelectronic applications. Their optical and electrical anisotropies and the possibility to control the alignment of the liquid-crystalline semiconductor allow not only to optimize charge carrier transport, but to tune the optical property of organic thin-film devices as well. In this study, the molecular orientation in a liquid-crystalline semiconductor film is tuned by a novel blading process as well as by different annealing protocols.

Ultrawide Band Gap β-GaO Nanomechanical Resonators with Spatially Visualized Multimode Motion.

Beta gallium oxide (β-GaO) is an emerging ultrawide band gap (4.5 eV-4.9 eV) semiconductor with attractive properties for future power electronics, optoelectronics, and sensors for detecting gases and ultraviolet radiation.