Macroscopic and microscopic analysis of the tongue of the common opossum (Didelphis marsupialis)

We performed a macroscopic and microscopic study of the tongues of common opossums, Didelphis marsupialis, from South America. We studied two males and two females. We collected morphometric data on the tongue with precision calipers. For the light microscopy and scanning electron microscopy analyses, we fixed tissue fragments in 10% formaldehyde and 2.5% glutaraldehyde, respectively. The opossum tongues averaged 5.87 ± 0.20 cm in length, 3.27 ± 0.15 cm in width at the lingual body, and 3.82 ± 0.15 cm in width at the root. The mean thickness of the lingual body was 1.8 ± 0.1 cm, and the thickness of the root was 3.82 ± 0.15 cm. Sharp filiform papillae were scattered across the entire tongue; conical filiform papillae occurred on the lingual body and tongue tip; fungiform papillae were scattered among the filiform papillae on the lingual body and tongue tip; and there were three vallate papillae at the root of the tongue. We found two strands of papillary projections in the tongue root. Despite the low variability observed in the lingual papillae, the morphological data obtained in this study may be related to the opossum's diverse food habits and the extensive geographic distribution of the species throughout America. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.     

Speech enhancement via Mel-scale Wiener filtering with a frequency-wise voice activity detector

This paper presents a speech enhancement system that enables a comfortable communication inside an automobile. A couple of novel concepts are proposed in an effort to improve two major building blocks in the existing speech enhancement systems: a voice activity detector (VAD) and a noise filtering algorithm. The proposed VAD classifies a given data frame as speech or noise at each frequency, enabling the frequency-wise updates of noise statistics and thereby improving the effectiveness of the noise filtering algorithms by providing more up-to-date noise statistics. The celebrated Wiener filter is adopted in this paper as the accompanying noise filtering algorithm, which results in significant noise suppression. Yet, the musical noise present in most Wiener filter-based systems prompts the idea of applying the Wiener filter in the Mel-scale in which the human auditory system responds to the external stimulation. It turns out that the Mel-scale Wiener filter creates some masking effects and thereby reduces musical noise significantly, leading to smooth transition between data frames.     

基于数据点正投影和曲面法矢的自由曲面造型

提出用控制自由曲面形状的数据点投影和曲面在数据点的法矢进行自由曲面造型的新思想。利用数据点的正投影 (二维坐标 )和曲面法线方向计算出数据点的三维坐标后 ,即可采用现有的自由曲面造型方法 ,如采用参数双三次样条曲面等自由曲面造型方法构造自由曲面。这种给定自由曲面数据的方法具有易于控制自由曲面形状、几何意义明显等优点     

Oscosurvismeter,A New Instrument for Osmotic Pressure,Conductance, Viscosity,and Surface Tension Measurements of Liquid Solutions of Chemical Substances

Abstract

The Oscosurvismeter is made of borosil glass material for measuring osmotic pressure (π), specific conductance (κ), viscosity (η), and surface tension (γ) of solutions. Solutions of different strengths are taken in two cells/compartments, partitioned by a semi‐permeable membrane (SPM). A concentration gradient makes the solvent move towards the concentrated solution to establish an equilibrium; this measures osmotic pressure (π). The Oscosurvismeter saves time and materials, and enhances accuracy and precision in measurements; the instrument consists of six parts: (1) survismeter; (2) osmometer; (3) electrode; (4) metallic clamp; (5) semipermeable membrane (SPM); and (6) high potential metallic springs. High accuracy data are noted with the instrument.     

Remote‐Loaded Platelet Vesicles for Disease‐Targeted Delivery of Therapeutics

The recent emergence of biomimetic nanotechnology has facilitated the development of next‐generation nanodelivery systems capable of enhanced biointerfacing. In particular, the direct use of natural cell membranes can enable multivalent targeting functionalities. Herein, this study reports on the remote loading of small molecule therapeutics into cholesterol‐enriched platelet membrane‐derived vesicles for disease‐targeted delivery. Using this approach, high loading yields for two model drugs, doxorubicin and vancomycin, are achieved. Leveraging the surface markers found on platelet membranes, the resultant nanoformulations demonstrate natural affinity toward both breast cancer cells and methicillin‐resistant Staphylococcus aureus. In vivo, this translates to improved disease targeting, increasing the potency of the encapsulated drug payloads compared with free drugs and the corresponding nontargeted nanoformulations. Overall, this work demonstrates that the remote loading of drugs into functional platelet membrane‐derived vesicles is a facile means of fabricating targeted nanoformulations, an approach that can be easily generalized to other cell types in the future.     

Quantification of shish–kebab and β‐crystal on the mechanical properties of polypropylene

The oriented “shish–kebab” structure and β‐crystal can enhance the mechanical properties of polypropylene products. In this regard, equipment and β‐nucleation agents have been developed or modified to form shish–kebab and β‐crystal. However, the effect of shish–kebab/β‐crystal proportion on the mechanical properties of polypropylene remains unclear. The answer is crucial but remains a challenge because of the difficulty in manipulating the shish–kebab proportion. In this work, we used a self‐made multiflow vibrate‐injection molding, which can provide a controllable shear flow, to produce samples with different shear‐layer thicknesses. The shish–kebab proportion was represented by R, which is the thickness ratio of the shear layer to that of the whole sample. Results showed that the tensile strength exponentially increased, whereas the elongation at break exponentially decreased, with R. The impact strength remained constant with R, indicating that the shish–kebab and β‐crystal possessed similar toughening effects. This work proposes a schematic to interpret the strengthening mechanism involved and presents a method of establishing and controlling the mechanical properties of polypropylene samples by using shish–kebab structures and β‐crystals. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45052.     

一种适用于蚊类扫描电镜样品简便快速的制备方法

本文介绍一种适合蚊类研究的扫描电镜样品制备方法.以库蚊为样品,用四氧化锇直接单固定处理,适当缩短脱水时间,改进临界点干燥前的制样程序.此方法观察效果良好,提高了样品制备质量,为蚊类扫描电镜样品制备提供了一种简易而快速的方法.     

静电纺间位芳纶纳米纤维的制备工艺参数

通过静电纺丝方法,将氯化锂/N,N–二甲基乙酰胺(Li Cl/DMAc)溶解间位芳纶(PMIA)制备了PMIA纳米纤维,探索了溶液浓度、接收距离、纺丝电压及接收速度等工艺参数对纤维形貌及其直径分布的影响。通过扫描电子显微镜观察了PMIA纳米纤维形貌及应用Image-J软件测量统计了PMIA纤维直径。结果表明,溶液浓度为8%~10%、纺丝电压为16~18 k V、接收距离为15~20 cm,接收速度60~80 r/min的范围内,间位芳纶纳米纤维成型良好,直径分布范围为100~120 nm;PMIA纳米纤维直径随着溶液浓度的减小、静电电压的增加而减小,随着接收速度的增加纤维取向增加。     

基于FMMEA方法的雷达液压升降系统分析

液压升降系统是执行雷达快速架撤功能的重要组成部分,然而其故障率相对较高.采用FMMEA方法对某雷达的液压升降系统进行了分析.结果表明,在液压升降系统中,故障模式影响的严酷度以Ⅱ级为主,说明系统故障风险较高.系统故障主要是由耗损型机理引起的,磨损和疲劳引起的故障分别占48%和26%.油泵电机轴承卡滞、 油缸密封圈损坏和液力锁内泄漏为危害性最大的故障模式.最后,根据分析结果提出了故障防治策略.     

负载型钴锰复合金属氧化物催化剂催化分解N_2O

以ZrO_2为载体,采用浸渍法制备负载型钴锰复合金属氧化物催化剂,研究催化剂活性组分负载量、Co与Mn物质的量比、焙烧条件及含H_2O气氛对N_2O转化率的影响。结果表明,催化剂最佳制备条件为:活性组分Co负载质量分数3%,Co与Mn物质的量比为1∶1,焙烧升温速率2℃·min-1,焙烧温度900℃。该条件制备的负载型钴锰复合金属氧化物催化剂在反应温度850℃时,N_2O转化率达98.7%。当反应气氛中H_2O体积分数小于20%条件下,850℃时N_2O转化率高于90%,表明催化剂具有较强的抗水性能。