Investigation of Resonator BWO-Based Spectroscopy of the Atmosphere in the THz Region

This paper intends to give a code about atmospheric propagation effects affecting terahertz (THz) communication system. The main focus is on attenuation caused by atmospheric gases with the radiation transmission theory and the empirical continuum absorption based on the HITRAN database. Theoretical aspects about them are presented, emphasizing on those which deserve special attention as frequency increases. Laboratory measurements of the absorption spectra of laboratory air and major atmospheric gases mixed with water vapor in the 250 - 350 GHz frequency range at atmospheric pressure and room temperature on a basis of backward wave oscillators (BWOs) are obtained. The results of experiments are compared with the calculations. It is found that the water vapor transmittance is greater than the calculation. Data of these measurements agree with the results of analysis of atmospheric spectra with in statistical accuracy of experiments. Accurate measurements are also needed for further studies of the physics of the molecules and their interactions. The investigation makes it significant for enhancing accuracy of models of radiation propagation in the atmosphere.

Ionomycin ameliorates hypophosphatasia via rescuing alkaline phosphatase deficiency-mediated L-type Ca^(2+) channel internalization in mesenchymal stem cells

The loss-of-function mutations in the ALPL result in hypophosphatasia(HPP), an inborn metabolic disorder that causes skeletal mineralization defects. In adults, the main clinical features are early loss of primary or secondary teeth, osteoporosis, bone pain,chondrocalcinosis, and fractures. However, guidelines for the treatment of adults with HPP are not available. Here, we show that ALPL deficiency caused a reduction in intracellular Ca2+ influx, resulting in an osteoporotic phenotype due to downregulated osteogenic differentiation and upregulated adipogenic differentiation in both human and mouse bone marrow mesenchymal stem cells(BMSCs). Increasing the intracellular level of calcium in BMSCs by ionomycin treatment rescued the osteoporotic phenotype in alpl+/- mice and BMSC-specific(Prrx1-alpl-/-) conditional alpl knockout mice. Mechanistically, ALPL was found to be required for the maintenance of intracellular Ca2+ influx, which it achieves by regulating L-type Ca2+ channel trafficking via binding to the α2δsubunits to regulate the internalization of the L-type Ca2+ channel. Decreased Ca2+ flux inactivates the Akt/GSK3β/β-catenin signaling pathway, which regulates lineage differentiation of BMSCs. This study identifies a previously unknown role of the ectoenzyme ALPL in the maintenance of calcium channel trafficking to regulate stem cell lineage differentiation and bone homeostasis. Accelerating Ca2+ flux through L-type Ca2+ channels by ionomycin treatment may be a promising therapeutic approach for adult patients with HPP.

硬脂酸改性NiO-TiO2薄膜的摩擦学性能

利用溶胶–凝胶技术结合自组装技术在45#钢表面制备了具有优异减摩耐磨性能的有机–无机复合薄膜。首先采用溶胶–凝胶技术在钢基底上制备NiO-TiO2薄膜,然后再用自组装技术在薄膜表面沉积硬脂酸分子获得有机–无机复合薄膜。利用接触角测量仪和X射线粉末衍射仪研究了薄膜的润湿性和晶体结构,用微纳摩擦磨损试验机研究了薄膜在干摩擦条件下与轴承钢球往复滑动的摩擦学性能。结果发现,经硬脂酸改性后得到的双层薄膜呈现高疏水状态,对水接触角达135°具有优异的摩擦学性能。

Peutz-Jeghers综合征基因型研究及临床诊治进展

Peutz-Jeghers综合征(PJS)是一种临床罕见的常染色体显性遗传病,该病以皮肤黏膜色素斑、胃肠道多发错构瘤息肉和家族遗传性为特征性临床表现,其罹患恶性肿瘤的发生率明显高于正常人群。该病的分子发病机制与抑癌基因STK11功能异常相关,但其遗传学背景复杂,临床异质性明显。目前的治疗以消化内镜的镜下治疗为主,辅之以外科手术,可显著延长患者的生存期,但尚无根治性的手段。本文复习了关于该病的相关文献,对其遗传学特性和临床治疗进展进行综述,并对未来的研究方向进行展望。

Dental stem cell and dental tissue regeneration

The teeth are highly differentiated chewing organs formed by the development of tooth germ tissue located in the jaw and consist of the enamel, dentin, cementum, pulp, and periodontal tissue. Moreover, the teeth have a complicated regulatory mechanism, special histologic origin, diverse structure, and important function in mastication, articulation, and aesthetics. These characteristics, to a certain extent, greatly complicate the research in tooth regeneration. Recently, new ideas for tooth and tissue regeneration have begun to appear with rapid developments in the theories and technologies in tissue engineering. Numerous types of stem cells have been isolated from dental tissue, such as dental pulp stem cells (DPSCs), stem cells isolated from human pulp of exfoliated deciduous teeth (SHED), periodontal ligament stem cells (PDLSCs), stem cells from apical papilla (SCAPs), and dental follicle cells (DFCs). All these cells can regenerate the tissue of tooth. This review outlines the cell types and strategies of stem cell therapy applied in tooth regeneration, in order to provide theoretical basis for clinical treatments.

Chromosome-level genome of Himalayan yew provides insights into the origin and evolution of the paclitaxel biosynthetic pathway

Taxus,commonly known as yew,is a well-known gymnosperm with great ornamental and medicinal value.In this study,by assembling a chromosome-level genome of the Himalayan yew(Taxus wallichiana)with 10.9 Gb in 12 chromosomes,we revealed that tandem duplication acts as the driving force of gene family evolution in the yew genome,resulting in the main genes for paclitaxel biosynthesis,i.e.those encoding the taxadiene synthase,P450s,and transferases,being clustered on the same chromosome.The tandem duplication may also provide genetic resources for the nature to sculpt the core structure of taxoids at different positions and subsequently establish the complex pathway of paclitaxel by neofunctionalization.Furthermore,we confirmed that there are two genes in the cluster encoding isoenzymes of a known enzyme in the paclitaxel biosynthetic pathway.The reference genome of the Himalayan yew will serve as a platform for decoding the complete biosynthetic pathway of paclitaxel and understanding the chemodi-versity of taxoids in gymnosperms.

Rapunzel综合征一例

患者,女性,16岁,主因“间断腹胀、腹痛不适4月余,加重2天”于2017年3月23日入院。患者于4月前因进食自己的头发、指甲后开始逐渐出现上腹胀痛不适,进食后症状加重,可自行缓解,无发热、恶心、呕吐等不适,就诊于当地医院给予对症治疗后症状好转。2天前患者腹胀、腹痛症状加重,并出现恶心、呕吐,在当地医院行电子胃镜检查,提示胃内可见巨大发丝团块,充满胃腔。为求手术治疗收住空军特色医学中心普通外科。

LiDAR signal denoising based on connected domains

The streak tube imaging light detection and ranging （LiDAR） is a new type of waveform sampling laser imaging radar whose echo signals are stripe images with a high frame rate. In this study, the morphological and statistical characteristics of stripe signals are analyzed in detail. Based on the concept of mathematical morphology denoising, connected domains are constructed in a noise- containing stripe image, and the noise is removed using the difference in connected domains area between signals and noises. It is shown that, for stripe signals, the proposed denoising method is significantly more efficient than Wiener filtering.

An improved strategy for out-of-step oscillation separation devices based on apparent impedance angle applied to a series compensated line

Out-of-step oscillation separation devices based on apparent impedance angle trajectory are widely used in the power grid in China,and their reliability is of great importance.In this paper,the influence mechanism of series compensation on apparent impedance angle trajectory is analyzed.It reveals that series compensation capacitors reduce the equivalent impedance angle and consequently the apparent impedance angle cannot pass through all four zones,resulting in the risk of failure for the separation devices.A revised method of apparent impedance angle based on compensation principle is discussed,and then an improved out-of-step oscillation detection criterion is proposed.In view of the fact that the apparent impedance angle at the moment of maximum current is equal to the equivalent impedance angle during an oscillation process,a practical algorithm based on the compensated apparent impedance angle is proposed.RTDS tests are conducted to verify the effectiveness of the new criterion,considering transmission lines with a high series compensation level.