Wind Tunnel Evaluation of a Rotating-Element Large-Particle Sampler

A large-particle sampler was tested in an environmental wind tunnel to characterize the efficiency as a function of particle size and type (solid or liquid). The sampler, which had been developed by another organization, has two slotted-cylinder collection elements which are rotated through air at a tangential speed of 39 m/s. Data from wind tunnel tests show the efficiency of liquid droplet collection to increase with particle size to approximately 50% at 25 μm and then decrease with a further increase in particle size. It is suggested that the air flow patterns created by the sampler produce this anomalous behavior. Results of tests with solid particles show higher efficiencies than are obtained with liquid droplets of the same size. It appears that solid particles, which rebound from collection sites other than a slot, can subsequently enter the slots. Supporting data were obtained on the performance of a single slotted cylinder that was fixed in the discharge region of a small free-jet tunnel. Those results show the impaction efficiency of all sizes of liquid droplets in the slotted cylinder follow the type of trend expected for a circular cylinder, i.e., a curve in which efficiency monotonically increases with size. However, 41-μ m diameter solid particles are re-entrained in the air stream and show reduced efficiency in comparison with liquid aerosol particles.     

Tubulin-Based Nanotubes as Delivery Platform for Microtubule-Targeting Agents

Tubulin-based nanotubes (TNTs) to deliver microtubule-targeting agents (MTAs) for clinical oncology are reported. Three MTAs, docetaxel (DTX), laulimalide (LMD), and monomethyl auristatin E (MMAE), which attach to different binding sites in a tubulin, are loaded onto TNTs and cause structural changes in them, including shape anisotropy and tubulin layering. This drug-driven carrier transformation leads to changes in the drug-loading efficiency and stability characteristics of the carrier. TNTs coloaded with DTX and LMD efficiently deliver dual drug cargoes to cellular tubulins by the endolysosomal pathway, and results in synergistic anticancer and antiangiogenic action of the drugs in vitro. In in vivo tests, TNTs loaded with a microtubule-destabilizing agent MMAE suppress the growth of tumors with much higher efficacy than free MMAE did. This work suggests a new concept of using a drug's target protein as a carrier. The findings demonstrate that the TNTs developed here can be used universally as a delivery platform for many MTAs.     

Rheological parameters determination using Near Infrared technology in whole wheat grain

Rheological properties of dough are important for wheat quality characterisation. This research sought to obtain prediction models for rheological characteristics and to characterise the breadmaking quality of whole wheat using NIRS (Near Infrared Reflectance Spectroscopy) technology, in order to offer a rapid tool to the farmers to know the quality of their product at the harvest moment. Tenacity (P), extensibility (L), deformation energy (W) and ratio P/L of dough were measured using traditional methods. NIR spectra were acquired from these samples. Models to predict the values from these parameters were developed. The SEC achieved for the extensibility, deformation energy and tenacity of dough and the ratio between the two latter parameters were 5.27 mm, 9.97 × 10⁻⁴ J, 3.98 mm and 0.025, respectively. The four models were validated by cross-validation, and by independent validation. The precision obtained in these models was enough for being applied in harvesters or at delivering moment.     

精确仿真一只LED

固态照明应用正在快速地成为主流。尽管它们有更高的效率,但其低成本发光的LED通常需要一种复杂的驱动电路。     

Toughening of in situ polymerized cyclic butylene terephthalate by addition of tetrahydrofuran

A new method of toughening polymerized cyclic butylene terephthalate (pCBT) with tetrahydrofuran (THF) is proposed. The pCBT was prepared by in situ ring‐opening polymerization of a commercial cyclic butylene terephthalate, a cyclic form of poly(butylene terephthalate), in the presence of THF. In comparison to conventionally polymerized pCBT, the resultant material was found to be ductile, showing a strain at break of well above 100% in tensile tests. Other matrix properties, such as tensile modulus, tensile strength and glass transition temperature, were not significantly altered by the addition of THF. It was found that the presence of THF enhanced the polymerization reaction, resulting in an increased molecular weight and a narrowed molecular weight distribution. Moreover, remaining oligomers after polymerization were extracted by the THF and a toughened oligomer‐free pCBT was obtained. The influence of time and temperature on the long‐time toughening action of THF was studied. The results showed that samples became brittle after 3 months when subjected to a temperature of 80 °C, resulting in a reduction of the toughening action. Copyright © 2010 Society of Chemical Industry     

Selective activation of mechanosensitive ion channels using magnetic particles.

This study reports the preliminary development of a novel magnetic particle-based technique that permits the application of highly localized mechanical forces directly to specific regions of an ion-channel structure. We demonstrate that this approach can be used to directly and selectively activate a mechanosensitive ion channel of interest, namely TREK-1. It is shown that manipulation of particles targeted against the extended extracellular loop region of TREK-1 leads to changes in whole-cell currents consistent with changes in TREK-1 activity. Responses were absent when particles were coated with RGD (Arg-Gly-Asp) peptide or when magnetic fields were applied in the absence of magnetic particles. It is concluded that changes in whole-cell current are the result of direct force application to the extracellular loop region of TREK-1 and thus these results implicate this region of the channel structure in mechano-gating. It is hypothesized that the extended loop region of TREK-1 may act as a tension spring that acts to regulate sensitivity to mechanical forces, in a nature similar to that described for MscL. The development of a technique that permits the direct manipulation of mechanosensitive ion channels in real time without the need for pharmacological drugs has huge potential benefits not only for basic biological research of ion-channel gating mechanisms, but also potentially as a tool for the treatment of human diseases caused by ion-channel dysfunction.     

Posttraumatic stress disorder's frequency and intensity ratings are associated with factor structure differences in military veterans.

We examined possible differences in the factor structure of posttraumatic stress disorder (PTSD) on the basis of whether frequency or intensity symptom response formats were used to assess PTSD. Participants included 669 veterans recruited from an epidemiological study of four Veterans Affairs Medical Centers' primary care clinics in the southeastern United States. Confirmatory factor analysis using measurement invariance testing found that the frequency and intensity symptom formats were significantly different from each other on PTSD's factor structure parameters, including factor loadings, observed variable intercepts, and measurement errors. The only exception was for PTSD's effortful avoidance symptoms, which were associated with equivalent parameter estimates for both the frequency and intensity formats. Implications for the clinical assessment of PTSD and interpretation of the extant literature base on PTSD's factor structure are considered. (PsycINFO Database Record (c) 2011 APA, all rights reserved)