Microscopic changing-mass model of PVA hydrogel under unidirectional compression

PVA (Polyvinyl Alcohol) hydrogel is a kind of soft materials, with nontoxic and good biocompatibility. This kind of hydrogel shows strong nonlinearity in the static compression tests because of the high water content (~60‑90%), and the water is squeezed out when the PVA hydrogel is compressed. It means that the PVA hydrogel losts the mass during compression. Aiming at the changing mass mechanism and constitution in the compression of PVA hydrogel, we established a simplified microscopic model which is a single layer frame composite structure consisting of PVA fibers, water, and virtual membrane, in which the membrane wraps outside surfaces of the cubic cells and has no mass, but its membrane force has same properties with the surface tension of water. In the model, the deformation of PVA fibers and the compressive water sustains the external stress when the PVA hydrogel is compressed. In addition, by considering the limitation of the maximum membrane force induced by compressive water, the squeezed water will be calculated in each compressive step and the mechanism of the changing mass is determined quantitatively; in the meantime, the constitution of the PVA hydrogel may be deduced

Prompt-driven Target Speech Diarization

We introduce a novel task named `target speech diarization', which seeks to determine `when target event occurred' within an audio signal. We devise a neural architecture called Prompt-driven Target Speech Diarization (PTSD), that works with diverse prompts that specify the target speech events of interest. We train and evaluate PTSD using sim2spk, sim3spk and sim4spk datasets, which are derived from the Librispeech. We show that the proposed framework accurately localizes target speech events. Furthermore, our framework exhibits versatility through its impressive performance in three diarization-related tasks: target speaker voice activity detection, overlapped speech detection and gender diarization. In particular, PTSD achieves comparable performance to specialized models across these tasks on both real and simulated data. This work serves as a reference benchmark and provides valuable insights into prompt-driven target speech processing.Comment: Accepted by ICASSP 202

Numerical analysis of yield properties of closed-cell aluminum foam under multiaxial loads by 3D voronoi model

Metallic foam is a typical porous material whose yield surface is related to not only von Mises equivalent stress but also the hydrostatic pressure. It is essential to study the yield properties of closed-cell aluminum foam under complex loading conditions. However, because the current experimental technique may support only a few proportions of multiaxial loading, it is hard to learn the yield surface well especially for the tensile hydrostatic pressure. In this article, we explored a numerical method to learn the yield properties of aluminum foam, in which the meso structures of aluminum foam were simulated by 3D Voronoi method. In addition, the yield surface of aluminum foam was drawn successfully with the numerical method. The main works included: (1) In our numerical simulation, we tested the calculating parameters such as mass scaling, elements number, and loading velocity on simulation results and verified the homogeneity of the 3D Voronoi model firstly. Furthermore, the optimized calculating parameters were determined by considering both reliability and feasibility of the calculation. Homogeneity of 3D Voronoi model was checked by the compression behaviors of aluminum in different directions. (2) In order to overcome the difficulty to determine critical yield state of metallic foams under complex loads, we recommended criterion by setting a dimensionless plastic dissipation value to determine the onset yield state of the foam under multiaxial loads. The critical value of dimensionless plastic dissipation was deduced from the common criterion—0.2% plastic strain in uniaxial loading, and the effect of relative densities on critical values was analyzed. (3) Three normal stresses were applied on cubic aluminum foam proportionally to implement the proportional loading. The different loading proportional factors of the three normal stresses were set widely to insure the yield surface including enough data, such as the hydrostatic loads cover from minimum negative to maximum positive values; each proportion has three loading proportional factors. Further, effects of the relative density on yield surface were investigated

Enhanced Fatigue and Durability of Carbon Black/natural rubber Composites Reinforced with Graphene Oxide and Carbon Nanotubes

Graphene oxide (GO) sheets and carbon nanotubes (CNTs) are of nanometer size and offer large shape factors which are beneficial in reducing crack propagation rates of composites when used in carbon black (CB) reinforced natural rubber (NR), thereby prolonging the service lives of rubber composites. In this research, CNT-CB/NR and GO-CB/NR composites were prepared by partially replacing CB with one-dimensional CNTs and two-dimensional flaky graphene oxide GO, respectively. The results showed that the complex filler dispersion in NR matrices was improved due to the isolation effect between the different fillers. The strain-induced crystallization (SIC) ability of CB/NR was effectively enhanced by the addition of both GO and CNT. The modulus at 100% strain and tear strength of the composites were also improved. More branching and deflections were observed at the crack tips of the composites and both effectively hindered crack propagation in the materials. Under uniaxial and multi-axial cyclic loading, the fatigue lives of CNT-CB/NR and GO-CB/NR composites greatly increased when compared with the fatigue lives of CB/NR composites. The GO-CB/NR composites exhibited evident advantages in respect of fatigue resistance and durability among the three composites

Influence of graphene oxide and carbon nanotubes on the fatigue properties of silica/styrene-butadiene rubber composites under uniaxial and multiaxial cyclic loading

The influence of equivalent replacement of silica (SiO2) by carbon nanotubes (CNT) or graphene oxide (GO) on the microstructure, mechanical and fatigue behaviors of SiO2/styrene-butadiene rubber (SBR) composites was investigated. Results showed that the synergistic effect between CNT (or GO) and SiO2 was beneficial for the filler network and improved the mechanical properties of SBR composites. Furthermore, the introduction of CNT (or GO) led to low crack growth rates and the crack propagation tips were easy to deflection. Under multiaxial fatigue conditions, the maximum engineering stress was determined to be a reliable fatigue life predictor for SBR composites

Increased Aortic Calpain-1 Activity Mediates Age-Associated Angiotensin II Signaling of Vascular Smooth Muscle Cells

Angiotensin II (Ang II) signaling, including matrix metalloproteinase type II (MMP2) activation, has been linked to an age-associated increase in migration capacity of vascular smooth muscle cells (VSMC), and to other proinflammatory features of arterial aging. Calpain-1 activation is required for MMP2 expression in fibroblasts and is induced in cardiomyocytes by Ang II. The consequences of engagement of calpain-1 with its substrates, however, in governing the age-associated proinflammatory status within the arterial wall, remains unknown.The present findings demonstrate that transcription, translation, and activity of calpain-1 are significantly up-regulated in rat aortae or early-passage aortic VSMC from old (30-mo) rats compared to young (8-mo). Dual immunolabeling of the arterial wall indicates that colocalization of calpain-1 and Ang II increases within the aged arterial wall. To further explore the relationship of calpain-1 to Ang II, we chronically infused Ang II into young rats, and treated cultured aortic rings or VSMC with Ang II. We also constructed adenoviruses harboring calpain-1 (CANP1) or its endogenous inhibitor calpastatin (CAST) and infected these into VSMC. Ang II induces calpain-1 expression in the aortic walls in vivo and ex vivo and VSMC in vitro. The Ang II mediated, age-associated increased MMP2 activity and migration in VSMC are both blocked by calpain inhibitor 1 or CAST. Over-expression of calpain-1 in young VSMC results in cleavage of intact vimentin, and an increased migratory capacity mimicking that of old VSMC, which is blocked by the MMP inhibitor, GM6001.Calpain-1 activation is a pivotal molecular event in the age-associated arterial Ang II/MMP2 signaling cascade that is linked to cytoskeleton protein restructuring, and VSMC migration. Therefore, targeting calpain-1 has the potential to delay or reverse the arterial remodeling that underlies age-associated diseases i.e. atherosclerosis

Infant 7-valent pneumococcal conjugate vaccine immunization alters young adulthood CD4+T cell subsets in allergic airway disease mouse model

Abstract7-Valent pneumococcal conjugate vaccine (PCV7) immunization in adulthood can inhibit allergic asthma in mouse model. The aim of this study is to investigate the effects of infant PCV7 immunization on young adulthood CD4+T cell subsets in a murine allergic airway disease (AAD) model. Our study indicated that infant PCV7 immunization can inhibit young adulthood airway inflammation and airway hyperresponsiveness (AHR) by inducing the production of Foxp3+Treg, Th1 cells and their cytokines IL-10 and IFN-γ, inhibiting the production of Th2, Th17 cells and their cytokines IL-13 and IL-17A in BALB/c mice model. These results suggested that infant PCV7 immunization may serve as an effective measure to prevent young adulthood mice AAD

Spatial analysis of malaria in Anhui province, China

<p>Abstract</p> <p>Background</p> <p>Malaria has re-emerged in Anhui Province, China, and this province was the most seriously affected by malaria during 2005–2006. It is necessary to understand the spatial distribution of malaria cases and to identify highly endemic areas for future public health planning and resource allocation in Anhui Province.</p> <p>Methods</p> <p>The annual average incidence at the county level was calculated using malaria cases reported between 2000 and 2006 in Anhui Province. GIS-based spatial analyses were conducted to detect spatial distribution and clustering of malaria incidence at the county level.</p> <p>Results</p> <p>The spatial distribution of malaria cases in Anhui Province from 2000 to 2006 was mapped at the county level to show crude incidence, excess hazard and spatial smoothed incidence. Spatial cluster analysis suggested 10 and 24 counties were at increased risk for malaria (<it>P </it>< 0.001) with the maximum spatial cluster sizes at < 50% and < 25% of the total population, respectively.</p> <p>Conclusion</p> <p>The application of GIS, together with spatial statistical techniques, provide a means to quantify explicit malaria risks and to further identify environmental factors responsible for the re-emerged malaria risks. Future public health planning and resource allocation in Anhui Province should be focused on the maximum spatial cluster region.</p