Persistent spin texture (PST) is the property of some materials to maintain a uniform spin configuration in the momentum space. This property has been predicted to support an extraordinarily long ...spin lifetime of carriers promising for spintronics applications. Here, we predict that there exists a class of noncentrosymmetric bulk materials, where the PST is enforced by the nonsymmorphic space group symmetry of the crystal. Around certain high symmetry points in the Brillouin zone, the sublattice degrees of freedom impose a constraint on the effective spin-orbit field, which orientation remains independent of the momentum and thus maintains the PST. We illustrate this behavior using density-functional theory calculations for a handful of promising candidates accessible experimentally. Among them is the ferroelectric oxide BiInO
-a wide band gap semiconductor which sustains a PST around the conduction band minimum. Our results broaden the range of materials that can be employed in spintronics.
Recent experimental results have demonstrated ferroelectricity in thin films of SrTiO_{3} induced by antisite Ti_{Sr} defects. This opens a possibility to use SrTiO_{3} as a barrier layer in ...ferroelectric tunnel junctions (FTJs)-emerging electronic devices promising for applications in nanoelectronics. Here using density functional theory combined with quantum-transport calculations applied to a prototypical Pt/SrTiO_{3}/Pt FTJ, we demonstrate that the localized in-gap energy states produced by the antisite Ti_{Sr} defects are responsible for the enhanced electron tunneling conductance which can be controlled by ferroelectric polarization. Our tight-binding modeling, which takes into account multiple defects, shows that the predicted defect-assisted tunneling electroresistance effect is greatly amplified when the defect energy levels are brought to the Fermi energy by one of the polarization states. Our results have implications for FTJs based on conventional ferroelectric barriers with defects and can be employed for the design of new types of FTJs with enhanced performance.
Commercially available ocular drug delivery systems are effective but less efficacious to manage diseases/disorders of the anterior segment of the eye. Recent advances in nanotechnology and molecular ...biology offer a great opportunity for efficacious ocular drug delivery for the treatments of anterior segment diseases/disorders. Nanoparticles have been designed for preparing eye drops or injectable solutions to surmount ocular obstacles faced after administration. Better drug pharmacokinetics, pharmacodynamics, non-specific toxicity, immunogenicity, and biorecognition can be achieved to improve drug efficacy when drugs are loaded in the nanoparticles. Despite the fact that a number of review articles have been published at various points in the past regarding nanoparticles for drug delivery, there is not a review yet focusing on the development of nanoparticles for ocular drug delivery to the anterior segment of the eye. This review fills in the gap and summarizes the development of nanoparticles as drug carriers for improving the penetration and bioavailability of drugs to the anterior segment of the eye.
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Members of the genus Aeromonas are opportunistic pathogen of a variety of aquatic animals that exhibits multidrug resistance, phenotypes, virulence genes and virulence. The present study described ...the species distribution and the potential pathogenicity of Aeromonas isolated from healthy Northern snakehead (Channa argus) in China. Molecular identification revealed that A. veronii biovar veronii (69/167; 41·3%) and A. hydrophila (41/167; 24·6%) were the most common species found in Northern snakehead intestine based on sequencing of the 16S rRNA gene and DNA gyrase subunit B protein. The distribution of seven virulence factors including aer (84·4%), act (80·8%), ser (40·1%), Aha (27·5%), lip (23·4%), exu (15·0%) and LuxS (12·6%) were determined exclusively in Aeromonas isolates. All the seven virulence genes were present in 9·6% (16/167), among which 11 strains were identified as A. veronii biovar veronii. For the strains harbouring seven virulence genes, the 50% lethal doses (LD50) of isolates were lower compared to the isolates carrying two virulence genes. The challenge tests revealed that isolate W31 had the lowest lethal dose, causing 50% mortality at 4·5 × 103 colony‐forming units (CFU) per ml. Furthermore, histopathology of Northern snakehead infected with Aeromonas strains showed necrosis and congestion in liver, spleen and kidney and also damage to the intestine. This study confirms that the Aeromonas strains isolated from healthy Northern snakehead may be a cause of concern for public health.
Significance and Impact of the Study
Aeromonas species are widely distributed in aquatic environments and have considerable virulence potential. The aim of this study was to identify Aeromonas strains isolated from healthy Northern snakehead, and to investigate if Aeromonas species isolated from healthy fish potential pathogenicity with special reference to virulence and epidemiology studies.
Significance and Impact of the Study: Aeromonas species are widely distributed in aquatic environments and have considerable virulence potential. The aim of this study was to identify Aeromonas strains isolated from healthy Northern snakehead, and to investigate if Aeromonas species isolated from healthy fish potential pathogenicity with special reference to virulence and epidemiology studies.
Precision spectroscopy of the hydrogen molecule is a test ground of quantum electrodynamics (QED), and it may serve for the determination of fundamental constants. Using a comb-locked cavity ...ring-down spectrometer, for the first time, we observed the Lamb-dip spectrum of the R(1) line in the overtone of hydrogen deuteride (HD). The line position was determined to be 217 105 182.79±0.03_{stat}±0.08_{syst} MHz (δν/ν=4×10^{-10}), which is the most accurate rovibrational transition ever measured in the ground electronic state of molecular hydrogen. Moreover, from calculations including QED effects up to the order m_{e}α^{6}, we obtained predictions for this R(1) line as well as for the HD dissociation energy, which are less accurate but signaling the importance of the complete treatment of nonadiabatic effects. Provided that the theoretical calculation reaches the same accuracy, the present measurement will lead to a determination of the proton-to-electron mass ratio with a precision of 1.3 parts per billion.
Abstract Previous data demonstrate that traumatic brain injury (TBI) activates autophagy, and increases microtubule-associated protein 1 light chain 3 (LC3) immunostaining mainly in neurons. However, ...the role of autophagy in traumatic brain damage remains elusive. The aim of the present study was to investigate the autophagic mechanisms participating in traumatic brain injury. The autophagy inhibitors 3-methyladenine (3-MA) and bafliomycin A1 (BFA) were administered with a single i.c.v. injection before TBI. We first examined the protein levels of Beclin-1 and LC3 II, which have been found to promote autophagy previously. Immunoblotting analysis showed that 3-MA pretreatment reduced post-TBI Beclin-1 and LC3-II levels, and maintained p62/SQSTM1 (p62) levels. In addition, double immunolabeling showed that the increased punctate LC3-II dots colocalizing with Propidium Iodide (PI)-stained nuclei at 24 h after injury, were partially inhibited by 3-MA pretreatment. Furthermore, inhibition of autophagy could reduce TBI-induced cell injury assessed with i.p. injection of PI and lesion volume, and attenuate behavioral outcome evaluated by motor test and Morris water maze. The neuroprotective effects were associated with an inhibition on TBI-induced up-regulation of LC3, Beclin-1, cathepsin B, caspase-3 and the Beclin-1/Bcl-2 ratio. Taken together, these data imply that the autophagy pathway is involved in the pathophysiologic responses after TBI, and inhibition of this pathway may help attenuate traumatic damage and functional outcome deficits.
Summary
We explored the association between gut microbiota composition and bone mineral loss in Chinese elderly people by high-throughput 16S ribosomal RNA (rRNA) gene sequencing. Compared with ...controls, a smaller number of operational taxonomic units (OTUs), several taxa with altered abundance, and specific functional pathways were found in individuals with low-bone mineral density (BMD).
Introduction
Gut microbiota plays important roles in human health and associates with a number of diseases. However, few studies explored its association with bone mineral loss in human.
Methods
We collected 102 fecal samples from each eligible individual belonging to low-BMD and control groups for high-throughput 16S rRNA gene sequencing.
Results
The low-BMD individuals had a smaller number of OTUs and bacterial taxa at each level. At the phylum level, Bacteroidetes were more abundant in the low-BMD group; Firmicutes were enriched in the control group; Firmicutes and Actinobacteria positively correlated and Bacteroidetes negatively correlated with the BMD and T-score in all subjects. At the family level, the abundance of Lachnospiraceae in low-BMD individuals reduced and positively correlated with BMD and T-score; meanwhile, BMD increased with increasing Bifidobacteriaceae. At the genus level, low-BMD individuals had decreased proportions of
Roseburia
compared with control ones (
P
< 0.05).
Roseburia
,
Bifidobacterium
, and
Lactobacillus
positively correlated with BMD and T-score. Furthermore, BMD increased with rising abundance of
Bifidobacterium
. Functional prediction revealed that 93 metabolic pathways significantly differed between the two groups (FDR-corrected
P
< 0.05). Most pathways, especially pathways related to LPS biosynthesis, were more abundant in low-BMD individuals than in control ones.
Conclusions
Several taxa with altered abundance and specific functional pathways were discovered in low-BMD individuals. Our findings provide novel epidemiologic evidence to elucidate the underlying microbiota-relevant mechanism in bone mineral loss and osteoporosis.
It has been reported that irisin regulated exercise-mediated adipocyte browning; however, the systematical effects of irisin on the metabolism of glucose and lipid in diabetes are largely unknown. In ...the present study, we investigated the role and underlying mechanism of irisin in glucose utilization and lipid metabolism in diabetic mice.
A mouse model of diabetes was established by feeding C57BL/6 mice with high-fat diet. The diabetic mice were then treated with irisin. To mimic type 2 diabetes in vitro, myocytes and hepatocytes were cultured in a medium of high glucose and high fat. Glucose uptake, fatty acid oxidation and the expression of related protein were evaluated.
Irisin improved glucose tolerance and glucose uptake as evidenced by increased (18)F-FDG accumulation and GLUT4 translocation in diabetic skeletal muscle. Irisin also increased glucose uptake in myocytes cultured in high glucose/high fatty acid medium. In contrast, irisin reduced the expression of PEPCK and G6Pase, which are involved in gluconeogenesis, in diabetic liver. Consistently, irisin reduced fat weight and serum total cholesterol and triglyceride levels in diabetic mice, but increased acetyl coenzyme A carboxylase-β phosphorylation in muscle tissue and uncoupling protein 1 expression in fat tissue. In addition, irisin increased the oxidation of fatty acid in myocytes. Knockdown of the adenosine monophosphate (AMP)-activated protein kinase (AMPK) attenuated the effects of irisin on glucose uptake and fatty acid β-oxidation in myocytes. Similarly, inhibition of AMPK by a specific inhibitor reduced the effects of irisin on PEPCK and G6Pase expression in hepatocytes.
Our results suggest that irisin has an essential role in glucose utilization and lipid metabolism, and irisin is a promising pharmacological target for the treatment of diabetes and its complications.
•Strategies for designing physical-stimuli-responsive nanotherapeutics are reviewed.•The chemistry of designing physical-stimuli-responsive nanomaterials is summarized.•The approaches to program ...nanomaterials by surface functionalization are compiled.•Methods to design nanotherapeutics with dual-stimuli responsiveness are discussed.
Nanomaterials that respond to externally applied physical stimuli such as temperature, light, ultrasound, magnetic field and electric field have shown great potential for controlled and targeted delivery of therapeutic agents. However, the body of literature on programming these stimuli-responsive nanomaterials to attain the desired level of pharmacologic responses is still fragmented and has not been systematically reviewed. The purpose of this review is to summarize and synthesize the literature on various design strategies for simple and sophisticated programmable physical-stimuli-responsive nanotherapeutics.
Here, we present a systematic approach to design different programmable physical-stimuli-responsive nanotherapeutics intended for controlled and targeted delivery of various therapeutic agents.
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