Regulation of interstitial fluid flow in adventitia along vasculature by heartbeat and respiration.

Converging studies showed interstitial fluid (ISF) adjacent to blood vessels flows in adventitia along vasculature into heart and lungs. We aim to reveal circulatory pathways and regulatory mechanism of such adventitial ISF flow in rat model. By MRI, real-time fluorescent imaging, micro-CT, and histological analysis, ISF was found to flow in adventitial matrix surrounded by fascia and along systemic vessels into heart, then flow into lungs via pulmonary arteries and back to heart via pulmonary veins, which was neither perivascular tissues nor blood or lymphatic vessels. Under physiological conditions, speckle-like adventitial ISF flow rate was positively correlated with heart rate, increased when holding breath, became pulsative during heavy breathing. During cardiac or respiratory cycle, each dilation or contraction of heart or lungs can generate to-and-fro adventitial ISF flow along femoral veins. Discovered regulatory mechanisms of adventitial ISF flow along vasculature by heart and lungs will revolutionize understanding of cardiovascular system.

Research on the Crack Risk of Early-Age Concrete under the Temperature Stress Test Machine.

A new temperature stress test machine (TSTM) was developed to improve temperature control accuracy and efficiency. As there is no uniform standard for the threshold value of TSTM, quite different threshold values are used in the test, which results in the influences of the threshold value on the evaluation of thermal stresses and crack risk of concrete not being determined. To illustrate the importance of an appropriate threshold value, different threshold values were used to evaluate the influences on the thermal stresses and cracking resistance of concrete specimens under a complete restraint test with semi-adiabatic temperature development. The results show that the maximum compressive stress of a concrete specimen with a threshold value 3 µÎµ was slightly larger than that of 1.5 µÎµ when the growth rate of tensile stress of the concrete specimen with the threshold value 3 µÎµ was slightly greater than that of concrete specimen with the threshold value 1.5 µÎµ. Based on the combination of crack risk coefficient and restraint degree, a new system for evaluating the crack resistance of concrete was proposed, in which different threshold values were used to estimate their influences on the crack risk of concrete. Thus, an appropriate range of threshold values could be determined.

Inorganic arsenic exposure increased expression of Fas and Bax gene in vivo and vitro.

Accumulating evidences have shown that apoptosis plays an important role in mediating the therapeutic effects and toxicity of arsenic. Fas and Bax genes are critical regulatory genes for apoptosis. In this study, we investigated the association between levels of Fas and Bax expression and the three arsenic species (inorganic arsenic (iAs), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA)) in vivo and vitro. Three arsenic species in urine were measured and levels of Fas and Bax expression were examined by the quantitative real-time PCR (qPCR) for all subjects. We found that Fas and Bax mRNA expression in the exposed group were significantly higher than that in the control group. The levels of gene expression were positively correlated with the concentrations of urinary iAs, MMA and DMA in all subjects. Sodium arsenite induced Fas and Bax mRNA expression, then MMA and DMA did not induce mRNA expression in MDA-MB-231 and XWLC-05 cells. The findings of the present study indicated that iAs, MMA, and DMA had different effects on expression of Bax and Fas gene.

Macro-Scale Strength and Microstructure of ZrW2O8 Cementitious Composites with Tunable Low Thermal Expansion.

Concretes with engineered thermal expansion coefficients, capable of avoiding failure or irreversible destruction of structures or devices, are important for civil engineering applications, such as dams, bridges, and buildings. In natural materials, thermal expansion usually cannot be easily regulated and an extremely low thermal expansion coefficient (TEC) is still uncommon. Here we propose a novel cementitious composite, doped with ZrW2O8, showing a wide range of tunable thermal expansion coefficients, from 8.65 × 10-6 °C-1 to 2.48 × 10-6 °C-1. Macro-scale experiments are implemented to quantify the evolution of the thermal expansion coefficients, compressive and flexural strength over a wide range of temperature. Scanning Electron Microscope (SEM) imaging was conducted to quantify the specimens' microstructural characteristics including pores ratio and size. It is shown that the TEC of the proposed composites depends on the proportion of ZrW2O8 and the ambient curing temperature. Macro-scale experimental results and microstructures have a good agreement. The TEC and strength gradually decrease as ZrW2O8 increases from 0% to 20%, subsequently fluctuates until 60%. The findings reported here provide a new routine to design cementitious composites with tunable thermal expansion for a wide range of engineering applications.

Nitrogen-rich carbon nitride hollow vessels: synthesis, characterization, and their properties.

Bulk quantities of nitrogen-rich graphitic carbon nitride are synthesized via a facile reactive pyrolysis process with a mixture of melamine and cyanuric chloride as the molecular precursors. Scanning electron microscopy and transmission electron microscopy studies show that micrometer-sized hollow vessels with high aspect ratios have been successfully elaborated without the designed addition of any catalyst or template. The composition of the prepared carbon nitride determined by combustion method is C(3)N(4.91)H(1.00)O(0.22), with the N/C ratio to be 1.64, indicating a high nitrogen content. X-ray diffraction pattern reveals the regular stacking of graphene CN(x) monolayers along the (002) direction with the presence of turbostratic ordering of C and N atoms in the a-b basal planes. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy investigations provide further evidence for graphite-like sp(2)-bonded building blocks based on both triazine and heptazine ring units bridged by 3-fold coordinated nitrogen atoms. The optical properties of the sample are investigated by UV-vis absorption and photoluminescence spectroscopy, which show features characteristic of pi-pi* and n-pi* electronic transitions involving lone pairs of nitrogen atoms. Thermogravimetric analysis curves of the synthesized graphitic carbon nitride hollow vessels show typical weight loss steps related to the volatilization of triazine and heptazine structural units.

Tandem Enyne Allene-Radical Cyclization: Low-Temperature Approaches to Benz[e]indene and Indene Compounds.

In an effort to lower the temperatures required to prepare multicyclic compounds using the tandem enediyne-radical cyclization, we have developed the tandem enyne allene-radical cyclization which proceeds at temperatures as low as 37 degrees C. The reactions were carried out using three different methods for the preparation of the enyne allenes. The first method involved the [3,3] sigmatropic rearrangement of an enediyne followed by a tandem enyne allene-radical cyclization. This reaction could be effected either by thermolysis (150 degrees C) or by AgBF(4) rearrangement followed by heating at 75 degrees C. A second technique utilized a [2,3] sigmatropic shift of an enediyne at -78 degrees C followed by tandem cyclization at 37 or 75 degrees C depending on the substrate. The final method involved the base-catalyzed isomerization of propargyl sulfones which yielded enyne allenes that underwent cyclization at 37 degrees C. These three sequences provide a method for the synthesis of ring systems using conditions that may be compatible with the sensitive functionality needed during the synthesis of complex natural products.