Beamline characterization of a dielectric-filled reentrant cavity resonator as beam current monitor for a medical cyclotron facility

At PSI (Paul Scherrer Institute), Switzerland, a superconducting cyclotron called “COMET” delivers proton beam of 250 MeV pulsed at 72.85 MHz for proton radiation therapy. Measuring proton beam currents (0.1–10nA) is of crucial importance for the treatment safety and is usually performed with invasive monitors such as ionisation chambers (ICs) which degrade the beam quality. A new non-invasive beam current monitor working on the principle of electromagnetic resonance is built to replace ICs in order to preserve the beam quality delivered. The fundamental resonance frequency of the resonator is tuned to 145.7 MHz, which is the second harmonic of the pulse rate, so it provides signals proportional to beam current. The cavity resonator installed in the beamline of the COMET is designed to measure beam currents for the energy range 238–70 MeV. Good agreement is reached between expected and measured resonator response over the energy range of interest. The resonator can deliver beam current information down to 0.15 nA for a measurement integration time of 1 s. The cavity resonator might be applied serving as a safety monitor to trigger interlocks within the existing domain of proton radiation therapy. Low beam currents limit the abilities to detect sufficiently, however, with the potential implementation of FLASH proton therapy, the application of cavity resonator as an online beam-monitoring device is feasible.     

利用微卫星遗传标记对恒河猴进行遗传同质性分群的探索

目的探索建立利用微卫星遗传标记对中国恒河猴免疫遗传学同质性分群的方法。方法根据已报道的中国恒河猴和印度恒河猴微卫星标记和与MHC基因高度连锁的微卫星遗传标记,对52只恒河猴进行了微卫星检测和遗传同质性分群。结果依据判断标准,可以将检测的恒河猴分为印度恒河猴,中国恒河猴和无法判定来源的恒河猴3个地理类别,并根据MHC附近的微卫星遗传标记将其分为若干MHC基因相同的同质性群体。结论此方法的建立将有利于恒河猴参与的实验分组,也为恒河猴繁殖管理提供了参考。     

一种袖珍式胎心音仪的设计和实现

研制出一种简单实用、安全可靠并具有广阔市场前景的袖珍式胎心音仪。该仪器利用超声多普勒原理,用超声探头从母体腹部提取胎儿心音信号,经过信号解调及低频放大、音频功率放大等处理,然后由耳机及扬声器输出胎心音。     

Neutrophil elastase inhibitor, sivelestat sodium hydrate prevents ischemia–reperfusion injury in the rat bladder

In the present study, we evaluated the effect of neutrophil elastase inhibitor, sivelestat sodium hydrate on ischemia–reperfusion injury in the rat bladder. Rat abdominal aorta was clamping with a small clip to induce ischemia–reperfusion injury in the bladder. Eight-week-old male Sprague Dawley rats were divided into four groups; sham-operated control rats, 30 min ischemia–60 min reperfusion (IR) rats, and IR rats treated with 15 or 60 mg/kg of sivelestat sodium hydrate. Sixty minutes prior to induction of ischemia, sivelestat sodium hydrate was administrated intraperitoneally. Real-time monitoring of blood flow and nitric oxide (NO) release were measured simultaneously with a laser Doppler flowmeter and an NO-selective electrode, respectively. The NO₂–NO₃ and malonaldehyde (MDA) concentrations were measured in the experimental urinary bladders. Clamping of the abdominal aorta, blood flow was rapidly decreased and NO release was gradually increased. After removing the clip, blood flow was rapidly increased and NO release was gradually returned to the basal level. These movements of blood flow and NO release were inhibited by treatment with sivelestat sodium hydrate in a dose-dependent manner. Both NO₂–NO₃ and MDA concentrations in the bladder were increased by induction of IR, and NO₂–NO₃ and MDA concentrations were decreased by treatment with high dose of sivelestat sodium hydrate significantly. Our data indicated that sivelestat sodium hydrate could inhibit increasing NO₂–NO₃ and MDA concentrations by IR, and it has potentiality protective effects on IR injury in the rat urinary bladder.     

硒-铁蛋白电化学反应器储存含磷化合物的研究

由透析袋、硒－铁蛋白、恒流泵、电导仪、磁力搅拌器及电化学系统等构成成硒－铁蛋白电化学反应器。该反应器可储存流动水体中微量含磷化合物于铁蛋白的蛋白壳内,其储存量高低与流动水体中的含磷化合物含量成正比关系。经硒改造后的硒－铁蛋白能提高有机磷农药的储存量,其储存能力与铁蛋白种类无关,可能与铁蛋白自身构象有关。     

The efficacy of a technology-based system in a short-term behavioral weight loss intervention

Objective: The objective was to examine the efficacy of adding a technology‐based program to an in‐person, behavioral weight loss intervention. Research Methods and Procedures: Fifty‐seven subjects (BMI = 33.1 ± 2.8 kg/m²; age = 41.3 ± 8.7 years) participated in a 12‐week intervention with random assignment to Standard In‐Person Behavioral Weight Control Program (SBWP) or Intermittent or Continuous Technology‐Based Program (INT‐TECH, CON‐TECH). SBWP subjects received seven individualized weight loss sessions encouraging dietary and exercise modifications. INT‐TECH and CON‐TECH subjects received all SBWP components; additionally, these groups used a SenseWear Pro Armband (BodyMedia, Inc.) to monitor energy expenditure and an Internet‐based program to monitor eating behaviors. These features were used by INT‐TECH subjects during weeks 1, 5, and 9 and CON‐TECH subjects weekly throughout the intervention. Results: Intent‐to‐treat analysis revealed weight loss of 4.1 ± 2.8 kg, 3.4 ± 3.4 kg, and 6.2 ± 4.0 kg, for SBWP, INT‐TECH, and CON‐TECH groups, respectively (CON‐TECH > INT‐TECH, p ≤ 0.05). Discussion: These results indicate that the technology‐based program needs to be used continuously throughout the intervention period to significantly impact weight loss. Future studies should examine the long‐term and independent effect of this technology on weight loss, and for whom this intervention format is most effective.     

Presence of robust circadian clock oscillation under constitutive over-expression of mCry1 in rat-1 fibroblasts

In mammals, mCRY proteins are essential and are major negative elements in circadian feedback loops. In this study, robust circadian clock oscillation was present even under conditions with constitutive over-expression of mCry1 in rat-1 cells. Rat-1 cells were produced to stably express mPer2 promoter-driven luciferase reporter, in which mCry1 was overexpressed under a tetracycline-dependent gene expression (Tet-On) system. Using these cells, we show that circadian clock oscillations in rat-1 fibroblasts persist when the mCRY1 protein constitutively accumulates in the nuclei.     

基于蓝牙4.0的便携式睡眠监测仪的研制

目的:实时监测睡眠状况,从而帮助人们特别是老人找到影响睡眠的原因。方法:设计了一个低功耗便携式睡眠监测仪,它是通过加速度传感器采集腕动信号、蓝牙4.0低功耗无线传输、Micro-SD卡存储、上位机显示等实现对睡眠状态的检测。为了验证睡眠监测仪的准确性,本文采用了视频分析方法,并且对不同人群进行监测。结果:研制的睡眠监测仪具有便携低功耗等特点,能够准确监测睡眠状态。结论:睡眠监测仪的研制对使用者特别是老人帮助很大,能够帮助使用者方便适时了解自己的睡眠状况,找到影响睡眠原因和改善睡眠质量方法。     

Learning-aided predictor integration for system performance prediction

The integration of multiple predictors promises higher prediction accuracy than the accuracy that can be obtained with a single predictor. The challenge is how to select the best predictor at any given moment. Traditionally, multiple predictors are run in parallel and the one that generates the best result is selected for prediction. In this paper, we propose a novel approach for predictor integration based on the learning of historical predictions. Compared with the traditional approach, it does not require running all the predictors simultaneously. Instead, it uses classification algorithms such as k-Nearest Neighbor (k-NN) and Bayesian classification and dimension reduction technique such as Principal Component Analysis (PCA) to forecast the best predictor for the workload under study based on the learning of historical predictions. Then only the forecasted best predictor is run for prediction. Our experimental results show that it achieved 20.18% higher best predictor forecasting accuracy than the cumulative MSE based predictor selection approach used in the popular Network Weather Service system. In addition, it outperformed the observed most accurate single predictor in the pool for 44.23% of the performance traces.

双侧颈总动脉结扎对大鼠学习记忆相关脑区血流量的影响

目的为建立双侧颈总动脉结扎致大鼠血管性痴呆模型,观察了大鼠双侧颈总动脉结扎后不同脑区脑血流量的影响。方法采用激光多普勒血流仪,测定麻醉大鼠双侧颈总动脉结扎后１０ｍｉｎ内不同脑区脑血流量变化。结果大鼠双侧颈总动脉结扎后,平均脑血流量减少额区６７８３％、顶区５６８２％、枕区１６１６％、Ｍｙｎｅｒｔ基底核５１２１％、尾壳核４１１８％,海马ＣＡ１５１８３和海马ＣＡ２４１２１。结论大鼠双侧颈总动脉结扎后与学习记忆有关的脑区脑血流量均显著下降