A mammalian genetic system to screen for small molecules capable of disrupting protein-protein interactions

A mammalian two-hybrid system was developed for high-throughput screening of compounds that disrupt specific protein-protein interactions. The existing mammalian systems are unsatisfactory for drug screening due to nonregulated expression of interacting proteins. To construct a tightly regulated system, the tetracycline repressor was fused with the inhibitory KRAB domain as a suppressor. The binding of the suppressor to the tet operator entirely blocked expression of two interacting proteins. When both the inducer doxycycline and drugs were added to the culture, the reporter gene was either activated by interaction of the paired proteins with ineffective drugs or remained silent due to disruption of the protein interactions by the effective drugs. We demonstrate that interactions of the type I receptor for TGFbeta with FKBP12 and the epidermal growth factor receptor (EGFR) with p85 are effectively disrupted by FK506 and EGFR kinase inhibitor AG1478, respectively. The power of this system for drug screening was further demonstrated by rapid identification of inhibitors from a druglike library for the receptor kinases.     

Analysis of passive mixing behavior in a poly(dimethylsiloxane) microfluidic channel using confocal fluorescence and Raman microscopy

Confocal fluorescence microscopy (CFM) and confocal Raman microscopy (CRM) have been applied to monitor the laminar flow mixing behavior in a poly(dimethylsiloxane) (PDMS) microfluidic channel. Two passive PDMS micromixing devices were fabricated for this purpose: a two-dimensional round-wave channel and a three-dimensional serpentine channel. The microscale laminar flow mixing of ethanol and isopropanol was evaluated using the CFM and CRM at various flow rates. The mixing behavior of confluent streams in the microchannel was assessed by determining the degree of color change in Rhodamine 6G dye on mixing using the CFM. However, it was also possible to quantitatively evaluate the mixing process without employing a fluorescence label using the CRM. The results show a strong potential for CRM as a highly sensitive detection tool to measure fundamental fluid mixing processes and to provide detailed information on chemical changes of non-fluorescent reaction mixtures in a PDMS microfluidic channel.     

Use of the CT images for BNCT calculation: development of BNCT treatment planning system and its applications to dose calculation for voxel phantoms

A BNCT (Boron Neutron Capture Therapy) treatment planning system (BTPS) was developed for BNCT study and treatment planning. Three kinds of CT images, VHP, PINNACLE and DICOM images, were employed to make voxel phantoms for BNCT patient treatment using the BTPS. The thermal neutron, fast neutron, gamma and boron doses are calculated and background, tissue, and tumour doses for idealised standard reactor neutron field (ISRNF) neutron beam were calculated by using BTPS and MCNP code. It was noted that the total computing times needed for BNCT analysis could be greatly reduced since the BTPS system provides a dose analysis tool and a lengthy MCNP input in a short time. It is, thus, expected that the BTPS can significantly contribute the BNCT study for the treatment of patients.     

Brain levels of <Emphasis Type="Italic">N</Emphasis>-acylethanolamine phospholipids in mice during pentylenetetrazol-induced seizure

The N-acylethanolamine phospholipids (NAPE) are precursors for N-acylethanolamines (NAE), including anandamide (20∶4-NAE), which is a ligand for the cannabinoid receptors. Previously, NAPE were believed to be found only in injured tissue, e.g., after neurodegenerative insults. Neuronal injury may occur in response to seizure activity. Therefore, we investigated the effect of pentylenetetrazol (PTZ)-induced seizures in PTZ-kindled mice on the level of NAPE in the brain. Male NMRI mice were kindled with PTZ injections 3 times/wk, thereby developing clonic seizures in response to PTZ. Mice were killed within 30 min after the clonic seizure on the test day (12th injection) and the brains were collected. Eight species of NAPE were analyzed as the glycerophospho-N-acylethanolamines by high-performance liquid chromatography-coupled electrospray ionization mass spectrometry. No effect of the PTZ kindling on the NAPE levels in murine brains was observed. Total NAPE in control mice cortex (n=4) was 16.4±3.0 μmol/g wet weight of which 20∶4-NAPE accounted for 3.6 mol%, and the major species was 16∶0-NAPE, accounting for 52.1 mol%. Determination of the activity of NAPE-hydrolyzing phospholipase D and of N-acyltransferase in brain membrane preparations from adult and 3-d-old mice revealed an enzyme pattern in the adult mice that was favorable for NAE accumulation as opposed to NAPE accumulation. Thus, there was no difference in NAPE levels; at present, however, this does not exclude that NAE may accumulate during seizure.     

Lethal effect of microwaves on spores of Bacillus spp

Strains representing four types of common heat-resistant spores of Bacillus spp., B. cereus CCRC 14655, B. coagulans CCRC10606, B. licheniformis CCRC14693, and B. subtilis CCRC14199, were heated with microwaves at different power levels and under different conditions in salt solutions, starch solutions, and containers. The results of this study showed that B. licheniformis spores had the highest microwave tolerance at a power level of 100% for different incubation times. B. coagulans spores showed the lowest microwave tolerance in salt solutions with water activity values of 0.6, 0.7, 0.8, and 0.9, and B. licheniformis spores were the most resistant in the tested salt solutions at different incubation times. An analysis of the effect of the viscosity of the medium revealed that the bacteria had the lowest microwave resistance in a medium containing <0.8% starch in solution. The microwave resistance levels of the test microorganisms were the lower in glass containers than in polypropylene containers and aluminum foil-enclosed pouches. Of the four species of bacilli, B. licheniformis had the highest microwave tolerance (P < 0.05) under all conditions.     

一种高抗辐射的SOI电脉冲时间间隔测定电路

研制出一种高抗辐射的 SOICMOS电脉冲时间间隔测定器集成电路。在阐述其工作原理的基础上 ,进行了抗辐射设计与版图设计。通过实验分析找到了向 SOI材料的 Si O2 埋层注入 F+ 离子的优化注入条件 ,有效地抑制 SOI CMOS器件的阈值电压的漂移 ,提高了电路的抗辐射性能。采用注入 F+离子 SOICMOS工艺投片后测试结果表明 :该电路与同类体硅电路相比 ,具有高速、低功耗、测量精度高以及优良的抗辐射性能     

Qualitative hydrological and land-use planning tool for the Israel Coastal aquifer

Due to a variety of past and present land-usages on the aquifer ground surface, appropriate groundwater management should consider anthropogenic activities on the ground surface and the potential of unsaturated zone media to convey water and pollutants to the aquifer. The objective of this paper is to present an approach which generates guidelines and recommendations which can lead to sustainable development. This method assesses the lithological characteristics of the aquifer's vadose zone, indicating potential rechargeability, while weighting factors leading to potential groundwater pollution resulting from some land-use. Recommendations regarding land-use planning and aquifer recharge can then provide a qualitative ecological tool towards sustainable groundwater management. Owing to its location, its critical significance to the country's fresh water supply, and its available field data, Israel's Coastal aquifer is employed here as the study area for implementation of this approach.     

All-optical wavelength conversion in a GaInAsP/InP optical gate loaded with a Bragg reflector

All-optical wavelength conversion employing a GaInAsP/InP nonlinear distributed-feedback waveguide switch is investigated. The device has the advantages of simple structure, compactness, polarity-noninverted operation, and feasibility of integration with other photonic devices such as semiconductor optical amplifier and modulators. We show that the device exhibits constant conversion efficiency around -9.2 dB in a signal-wavelength range of 1530-1560 nm. Furthermore, this device can potentially be made polarization independent.     

Absorption of water by room-temperature ionic liquids: effect of anions on concentration and state of water

Near-infrared (NIR) spectrometry was successfully used for the non-invasive and in situ determination of concentrations and structure of water absorbed by room-temperature ionic liquids (RTILs). It was found that RTILs based on 1-butyl-3-methylimidazolium, namely, [BuMIm]+ [BF4]-, [BuMIm]+ [bis((trifluoromethyl)sulfonyl)amide, or Tf2N]- and [BuMIm]+ [PF6]-, are hydroscopic and can quickly absorb water when they are exposed to air. Absorbed water interacts with the anions of the RTILs, and these interactions lead to changes in the structure of water. Among the RTILs studied, [BF4]- provides the strongest interactions and [PF6]- the weakest. In 24 hours, [Bu-MIm]+ [BF4]- can absorb up to 0.320 M of water, whereas [Bu-MIm]+ [PF6]- can only absorb 8.3 x 10(-2) M of water. It seems that higher amounts of water can be absorbed when the anion of the RTIL can strongly interact and hence stabilize absorbed water molecules by forming hydrogen bonds with them or inducing hydrogen bonds among water molecules. More importantly, the NIR technique can be sensitively used for the noninvasive, in situ determination of absorbed water in RTILs, without any pretreatment, and at limits of detection as low as 3.20 x 10(-3) M.     

Microchip-based purification of DNA from biological samples

A microchip solid-phase extraction method for purification of DNA from biological samples, such as blood, is demonstrated. Silica beads were packed into glass microchips and the beads immobilized with sol-gel to provide a stable and reproducible solid phase onto which DNA could be adsorbed. Optimization of the DNA loading conditions established a higher DNA recovery at pH 6.1 than 7.6. This lower pH also allowed for the flow rate to be increased, resulting in a decrease in extraction time from 25 min to less than 15 min. Using this procedure, template genomic DNA from human whole blood was purified on the microchip platform with the only sample preparation being mixing of the blood with load buffer prior to loading on the microchip device. Comparison between the microchip SPE (microchipSPE) procedure and a commercial microcentrifuge method showed comparable amounts of PCR-amplifiable DNA could be isolated from cultures of Salmonella typhimurium. The greatest potential of the microchipSPE device was illustrated by purifying DNA from spores from the vaccine strain of Bacillus anthracis, where eventual integration of SPE, PCR, and separation on a single microdevice could potentially enable complete detection of the infectious agent in less than 30 min.