Hydrophobicity engineering of cholera toxin A1 subunit in the strong adjuvant fusion protein CTA1-DD

Protein engineering of the cholera toxin A1 subunit (CTA1) fusedto a dimer of the Ig-binding D-region of Staphylococcus aureusprotein A (DD) was employed to investigate the effect of specificamino acid changes on solubility, stability, enzymatic activityand capacity to act as an adjuvant in vivo. A series of CTA1-DDanalogues were selected by a rational modeling approach, inwhich surface-exposed hydrophobic amino acids of CTA1 were exchangedfor hydrophilic counterparts modeled for best structural fit.Of six different mutants initially produced, two analogues,CTA1Phe132Ser-DD and CTA1Pro185Gln-DD, were demonstrated tohave 50 and 70% increased solubility, respectively, at neutralpH. The double mutant CTA1Phe132Ser/Pro185Gln-DD was at leastthreefold more soluble, demonstrating an additive effect ofthe two mutations. Only the Phe132Ser analogue retained fullbiological activity and stability compared with the native CTA1-DDfusion protein. Two mutants, Pro185Gln and Phe31His mutations,exhibited unaltered ADP-ribosyltransferase activity in vitro,but demonstrated markedly reduced adjuvant function. Since thePro185 and Phe31 amino acids are located in close vicinity onthe distal side of the molecule relative to the enzymaticallyactive cleft, it is conceivable that this region is involvedin mediating a biological function, separate from the enzymaticactivity but intrinsic to the adjuvant activity of CTA1.     

GSM协议分析仪CRTU-G

罗德与施瓦茨(Rohde & Schwarz)公司的通用协议测试仪CRTU-G基于可升级的射频单元,可以不断更新以符合将来的标准,能仿真GSM基站,并且可以用用户定义的任何信令模式对移动电话进行测试.此外,CRTU-G也实现了GSM基站的参考功能.CRTU-G用于开发移动系统及其相应的芯片组,并支持协议栈的软件开发,向更高的协议层提供规范接口.CRTU-G还用于测试移动系统是否符合GSM认证论坛(GCF)规范.     

Commercially available alternatives to palm oil

Since several years there has been a demand for food products free of palm oil, noticeable in the Western European market. Alternatives based on liquid oils, fully hydrogenated fats, and exotic fats like shea and sal etc., have been developed by the research groups of several specialty oils and fats suppliers. This article describes the advantages and disadvantages of those products and compares them to similar products based on palm oil. It is also discussed how reasonable the replacement of palm products would be, since sustainable and 3‐MCPD/glycidolester‐reduced palm based specialty oils are also available on the market.     

Pedestrian crossing situations: Quantification of comfort boundaries to guide intervention timing

Introduction

Technical systems that warn or brake for vehicle–pedestrian encounters reduce injuries more effectively the earlier an intervention is initiated. However, premature intervention can irritate drivers, leading to system deactivation and, consequently, no injury reduction whatsoever. It has been proposed that no intervention should be initiated as long as attentive drivers are within their comfort zones. This study aims at quantifying driver comfort boundaries for pedestrian crossing situations to offer guidance for the appropriate timing of interventions.

Methods

Sixty two volunteers drove through an intersection on a test track at 30 and 50 km/h. A pedestrian dummy was launched from behind an obstruction towards the driving path of the approaching car. Brake onset indicated discomfort. Time to collision (TTC), longitudinal and lateral distance were measured at brake onset.

Results

TTC was independent of driving speed ranging from 2.1 to 4.3 s with a median of 3.2 s. Longitudinal distance ranged from 19 to 48 meters with an apparent difference between driving speeds. Lateral distances differed slightly, but significantly between driving speeds. The median was 3.1 m (3.2 m for 30 km/h and 2.9 m for 50 km/h) and values ranged from 1.9 to 4.1 m. Lateral distance in seconds ranged from 1.9 to 4.3 s with a median value of 3.1 s (3.2 s for 30 km/h and 3.0 s for 50 km/h).

Discussion

TTC was independent of driving speed, trial order and volunteer age. It might be considered suitable to intervene in situations where, for example, 90% of drivers have exceeded their comfort boundary, i.e. when drivers have already initiated braking. This percentile value translates to intervention at a TTC of 2.5 s (95% confidence 2.4–2.7 s). The study was limited to Swedish nationals, fully aware drivers, and two driving speeds, but did not investigate behavioural changes due to system interaction.

Conclusion

This study showed that TTC at brake onset was a suitable measure for the quantification of driver comfort boundaries in pedestrian crossing situations. All drivers applied their brakes prior to 2.1 s TTC.     

Distance and velocity measures: using citations to determine breadth and speed of research impact

Research that integrates the social and natural sciences is vital to address many societal challenges, yet is difficult to arrange, conduct, and disseminate. This paper compares diffusion of the research supported by a unique U.S. National Science Foundation program on Human and Social Dynamics (“HSD”) with a matched group of heavily cited papers. We offer a measure of the distance of cites between the Web of Science Category (“WoSC”) in which a publication appears and the WoSC of the journal citing it, and find that HSD publications are cited more distantly than are comparison publications. We provide another measure—citation velocity—finding that HSD publications are cited with similar lag times as are the comparison papers. These basic citation distance and velocity measures enrich analyses of research knowledge diffusion patterns.     

Comparing Linear Viscoelastic Properties of Asphalt Concrete Measured by Laboratory Seismic and Tension–Compression Tests

Seismic measurements and conventional cyclic loading have been applied to a cylindrical asphalt concrete specimen to compare the complex modulus and complex Poisson’s ratio between the two testing methods. The seismic moduli and Poisson’s ratio have been characterized by optimizing finite element calculated frequency response functions to measurements performed at different temperatures. An impact hammer and an accelerometer were used to measure the frequency response functions of the specimen which was placed on soft foam for free boundary conditions. The cyclic loading was performed by applying both tension and compression to the specimen while measuring the displacements in the axial and radial direction. The Havriliak–Negami and the 2S2P1D model have been used to estimate master curves of the complex modulus and complex Poisson’s ratio from the seismic and the tension–compression tests. The seismic measurements performed at a lower strain level than the tension–compression test give a higher absolute value of the complex moduli (e.g. \({\sim }12\,\%\) at 100 Hz) and a lower phase angle compared to the tension–compression results.     

Layered Perovskite Nanofibers via Electrospinning for Overall Water Splitting

The (111)‐layered perovskite materials Ba₅Ta₄O₁₅, Ba₅Ta₂Nb₂O₁₅ and Ba₅Nb₄O₁₅ are prepared with nanofiber morphology via electrospinning for the first time. The nanofibers are built up from small single crystals, with up to several micrometers length even after calcination. The formation mechanism is investigated in detail, revealing an intermediate formation of amorphous barium carbonate strengthening the nanofiber morphology for high temperature treatment. All nanofiber compounds are able to generate hydrogen without any co‐catalyst in photocatalytic reformation of methanol. After photodeposition of Rh‐Cr₂O₃ co‐catalysts, the nanofibers show better activity in overall water splitting compared to sol–gel‐derived powders.