166 research outputs found
Controllable Plasmonic Nanostructures induced by Dual-wavelength Femtosecond Laser Irradiation
We demonstrated an abnormal double-peak (annular shaped) energy deposition through dualwavelength synthesis of the fundamental frequency (ω) and the second-harmonic frequency (2ω) of a femtosecond (fs) Ti:sapphire laser. The annular shaped distribution of the dual-wavelength fs laser was confirmed through real beam shape detection. This uniquely simple and flexible technique enables the formation of functional plasmonic nanostructures. We applied this double-peak fs-laser-induced dewetting effect to the controlled fabrication and precise deposition of Au nanostructures, by using a simple, lithography-free, and single-step process. In this process, the double-peak energy-shaped fs laser pulse induces surface patterning of a thin film followed by nanoscale hydrodynamic instability, which is highly controllable under specific irradiation conditions. Nanostructure morphology (shape, size, and distribution) modulation can be achieved by adjusting the laser irradiation parameters, and the subsequent ion-beam polishing enables further dimensional reduction and removal of the surrounding film. The unique optical properties of the resulting nanostructure are highly sensitive to the shape and size of the nanostructure. In contrast to a nanoparticle, the resonance-scattering spectrum of an Au nanobump exhibites two resonance peaks. These suggest that the dual-wavelength fs laserbased dewetting of thin films can be an effective means for the scalable manufacturing of patterned functional nanostructures
Saliency-Aware Regularized Graph Neural Network
The crux of graph classification lies in the effective representation
learning for the entire graph. Typical graph neural networks focus on modeling
the local dependencies when aggregating features of neighboring nodes, and
obtain the representation for the entire graph by aggregating node features.
Such methods have two potential limitations: 1) the global node saliency w.r.t.
graph classification is not explicitly modeled, which is crucial since
different nodes may have different semantic relevance to graph classification;
2) the graph representation directly aggregated from node features may have
limited effectiveness to reflect graph-level information. In this work, we
propose the Saliency-Aware Regularized Graph Neural Network (SAR-GNN) for graph
classification, which consists of two core modules: 1) a traditional graph
neural network serving as the backbone for learning node features and 2) the
Graph Neural Memory designed to distill a compact graph representation from
node features of the backbone. We first estimate the global node saliency by
measuring the semantic similarity between the compact graph representation and
node features. Then the learned saliency distribution is leveraged to
regularize the neighborhood aggregation of the backbone, which facilitates the
message passing of features for salient nodes and suppresses the less relevant
nodes. Thus, our model can learn more effective graph representation. We
demonstrate the merits of SAR-GNN by extensive experiments on seven datasets
across various types of graph data. Code will be released.Comment: Accepted by Artificial Intelligence Journal with minor revisio
Manipulation of LIPSS orientation on silicon surfaces using orthogonally polarized femtosecond laser double-pulse trains
Laser-induced periodic surface structures (LIPSS) provide an easy and costeffective means of fabricating gratings and have been widely studied in recent decades. To overcome the challenge of orientation controllability, we developed a feasible and efficient method for manipulating the orientation of LIPSS in real time. Specifically, we used orthogonally polarized and equal-energy femtosecond laser (50 fs, 800 nm) double-pulse trains with time delay about 1ps, total peak laser fluence about 1.0 J/cm2, laser repetition frequency at 100 Hz and scanning speed at 150 μm/s to manipulate the LIPSS orientation on silicon surfaces perpendicular to the scanning direction, regardless of the scanning paths. The underlying mechanism is attributed to the periodic energy deposition along the direction of surface plasmon polaritons (SPPs), which can be controlled oriented along the scanning direction in orthogonally polarized femtosecond laser double-pulse trains surface scan processing. An application of structural colors presents the functionality of our method
Manipulation of LIPSS orientation on silicon surfaces using orthogonally polarized femtosecond laser double-pulse trains
Laser-induced periodic surface structures (LIPSS) provide an easy and costeffective means of fabricating gratings and have been widely studied in recent decades. To overcome the challenge of orientation controllability, we developed a feasible and efficient method for manipulating the orientation of LIPSS in real time. Specifically, we used orthogonally polarized and equal-energy femtosecond laser (50 fs, 800 nm) double-pulse trains with time delay about 1ps, total peak laser fluence about 1.0 J/cm2, laser repetition frequency at 100 Hz and scanning speed at 150 μm/s to manipulate the LIPSS orientation on silicon surfaces perpendicular to the scanning direction, regardless of the scanning paths. The underlying mechanism is attributed to the periodic energy deposition along the direction of surface plasmon polaritons (SPPs), which can be controlled oriented along the scanning direction in orthogonally polarized femtosecond laser double-pulse trains surface scan processing. An application of structural colors presents the functionality of our method
Effects of synthetic colloids on oxidative stress and inflammatory response in hemorrhagic shock: comparison of hydroxyethyl starch 130/0.4, hydroxyethyl starch 200/0.5, and succinylated gelatin
INTRODUCTION: This study compared the effects of hydroxyethyl starch 130/0.4, hydroxyethyl starch 200/0.5, and succinylated gelatin on oxidative stress and the inflammatory response in a rodent hemorrhagic shock model. METHODS: Sodium pentobarbital-anesthetized adult male Wistar rats (200 g to 220 g) were subjected to a severe volume-controlled hemorrhage using arterial blood withdrawal (30 mL/kg to 33 mL/kg) and resuscitated with a colloid solution at the same volume as blood withdrawal (hydroxyethyl starch 130/0.4, hydroxyethyl starch 200/0.5, or succinylated gelatin). Arterial blood gas parameters were monitored. Malondialdehyde (MDA) content and myeloperoxidase (MPO) activity in the liver, lungs, intestine, and brain were measured two hours after resuscitation. The levels of tumor necrosis factor-alpha (TNF-α) and interleukin-6 in the intestine were also measured. RESULTS: Infusions of hydroxyethyl starch 130/0.4, but not hydroxyethyl starch 200/0.5 or succinylated gelatin, significantly reduced MDA levels and MPO activity in the liver, intestine, lungs and brain, and it also inhibited the production of TNF-α in the intestine two hours after resuscitation. However, no significant difference between hydroxyethyl starch 200/0.5 and succinylated gelatin was observed. CONCLUSIONS: Hydroxyethyl starch 130/0.4, but not hydroxyethyl starch 200/0.5 or succinylated gelatin, treatment after hemorrhagic shock ameliorated oxidative stress and the inflammatory response in this rat model. No significant differences were observed after hydroxyethyl starch 200/0.5 or succinylated gelatin administration at doses of approximately 33 mL/kg
Structure-Mediated Excitation of Air Plasma and Silicon Plasma Expansion in Femtosecond Laser Pulses Ablation
Femtosecond laser-induced surface structures upon multiple pulses irradiation are strongly correlated with the pulse number,which in turn significantly affects successive laser-material interactions. By recording the dynamics of femtosecond laser ablation of silicon using time-resolved shadowgraphy, here we present direct visualization of the excitation of air plasma induced by the reflected laser during the second pulse irradiation.The interaction of the air plasma and silicon plasma is found to enhance the shockwave expansion induced by silicon ablation in the longitudinal direction, showing anisotropic expansion dynamics in different directions. We further demonstrate the vanishing of air plasma as the pulse number increases because of the generation of a rough surface without light focusing ability. In the scenario, the interaction of air plasma and silicon plasma disappears; the expansion of the silicon plasma and shockwave restores its original characteristic that is dominated by the laser-material coupling.The results show that the excitation of air plasma and the laser-material coupling involved in laser-induced plasma and shockwave expansion are structure mediated and dependent on the pulse number, which is of fundamental importance for deep insight into the nature of laser-material interactions during multiple pulses ablation
PL-010 Chronic mild stress improves glucose homeostasis via myonectin-mediated suppression of sympathetic activity in high-fat diet-fed mice
Objective Recent studies suggest that chronic stress exposure can ameliorate the progression of diet-induced prediabetic disease, by inhibiting an increase in weight gain, caloric intake and efficiency and insulin resistance. To determine the underlying mechanism by which chronic stress improves the progression of type 2 diabetes, we developed a model of chronic mild stress in high-fat diet(HFD)-fed mice which are resistant to obesity and exhibit a healthy-like metabolic phenotype.
Methods High-fat diet (HFD): 45% kcal derived from fat (Research Diets, Inc.).Mice experienced one stressor during the day and a different stressor during the night. Stressors were randomly chosen from the following list : cage tilt on a 45° angle for 1 to 16 h; food deprivation for 12 to 16 h; white noise for 1 to 16 h; strobe light illumination for 1 to 16 h; crowded housing; light cycle (continuous illumination) for 24 to 36 h; dark cycle (continuous darkness) for 24 to 36 h; water deprivation for 12 to 16 h; damp bedding (200 ml water poured into sawdust bedding) for 12 to 16 h.Recombinant adeno-associated virus (AAV): AAV9 vectors encoding myonectin under the control of the ubiquitous CMV promoter (AAV9-CMV-Vip) or an equal dose of the AAV9-CMV-null vector were delivered to C57BL/6 mice by the tail vein. Mice were deprived of food for 16 h and then subjected to test 7 days after AAV injection.
Results Chronic stress improved glucose intolerance and sympathetic overactivity in HFD-fed mice. Chronic stress attenuated epinephrine(EPI)-stimulated glycerol release into blood in vivo and accelerated glycerol release from white adipose tissue followed by in vitro incubation with EPI. Chronic stress reduced plasma triglyceride but increased the levels of plasma insulin and myonectin. We further found that adeno-associated virus 9 (AAV9)-mediated myonectin overexpression improved glucose homeostasis and reduced epinephrine sensitivity. Myonectin overexpression reduced plasma norepinephrine, EPI and leptin levels, and increased insulin sensitivity in brown and white adipose tissue. Intense sympathetic activity with high-intensity running inhibited myonectin expression in skeletal muscle, whereas medium and low-intensity exercise running increased myonectin expression.
Conclusions These findings suggest that chronic mild stress can improve glucose homeostasis via myonectin-mediated suppression of sympathetic activity in high-fat diet-fed mice
Leben und Zusammenleben der Sprachgruppen in Südtirol: Auswirkungen von Autonomie und Minderheitenschutz auf Schule und Bevölkerung
Effect of TP on Biochemical Indicators. (DOCX 14 kb
Molecular characterization of florfenicol and oxazolidinone resistance in Enterococcus isolates from animals in China
Florfenicol is widely used for the treatment of bacterial infections in domestic animals. The aim of this study was to analyze the molecular mechanisms of florfenicol and oxazolidinone resistance in Enterococcus isolates from anal feces of domestic animals. The minimum inhibitory concentration (MIC) levels were determined by the agar dilution method. Polymerase chain reaction (PCR) was performed to analyze the distribution of the resistance genes. Whole-genome sequencing and comparative plasmid analysis was conducted to analyze the resistance gene environment. A total of 351 non-duplicated enteric strains were obtained. Among these isolates, 22 Enterococcus isolates, including 19 Enterococcus. faecium and 3 Enterococcus. faecalis, were further studied. 31 florfenicol resistance genes (13 fexA, 3 fexB, 12 optrA, and 3 poxtA genes) were identified in 15 of the 19 E. faecium isolates, and no florfenicol or oxazolidinone resistance genes were identified in 3 E. faecalis isolates. Whole-genome sequencing of E. faecium P47, which had all four florfenicol and oxazolidinone resistance genes and high MIC levels for both florfenicol (256 mg/L) and linezolid (8 mg/L), revealed that it contained a chromosome and 3 plasmids (pP47-27, pP47-61, and pP47-180). The four florfenicol and oxazolidinone resistance genes were all related to the insertion sequences IS1216 and located on two smaller plasmids. The genes fexB and poxtA encoded in pP47-27, while fexA and optrA encoded in the conjugative plasmid pP47-61. Comparative analysis of homologous plasmids revealed that the sequences with high identities were plasmid sequences from various Enterococcus species except for the Tn6349 sequence from a Staphylococcus aureus chromosome (MH746818.1). The current study revealed that florfenicol and oxazolidinone resistance genes (fexA, fexB, poxtA, and optrA) were widely distributed in Enterococcus isolates from animal in China. The mobile genetic elements, including the insertion sequences and conjugative plasmid, played an important role in the horizontal transfer of florfenicol and oxazolidinone resistance
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