基于平板探测器的DR系统原理及使用维护

针对采用平板探测器技术做为数字化方案实现的直接数字化X线摄影系统，本文重点探讨了平板探测器特点，介绍了系统的工作原理和成像技术，以及系统日常在设备运行过程中的维护技术。     

冰片对大鼠下丘脑单胺类神经递质的影响

目的观察天然冰片对大鼠下丘脑单胺类神经递质 NE、E、5-HT、'DA含量的影响,同时进行其时效和量效关系的观察,初步探讨冰片的作用靶点和作用机理.方法将1 68只Wistar大鼠随机分组,分别灌服生理盐水、1%CMC-NA,以及高、中、低剂量的冰片,每天灌胃2次,在0、45min、24h、72h、120h不同时相,用高效液相-电化学法检测大鼠下丘脑单胺类神经递质NE、E、5-HT、DA含量.结果灌服冰片45min后,冰片中、高剂量组对下丘脑NE含量有显著降低作用(P＜0.05);对下丘脑E的含量,中、高剂量组和CMC-NA组相比有明显的降低作用(P＜0.05);连续灌胃后,不同时相冰片各组下丘脑NE、E含量和CMC-NA组相比,继续呈现不同程度的下降作用,但对下丘脑5-HT无显著影响;在连续灌胃5d后,对 DA含量有显著降低作用(P＜0.05).对大脑皮层乙酰胆碱含量无显著影响,对单胺氧化酶含量有升高的趋势,但除在24h时相,冰片中、高剂量组差异有显著性意义外(P＜0.05),其余时相无显著差异.结论冰片在各个时相均有降低下丘脑NE、E含量的作用,而且随着剂量的递增,对下丘脑中的NE、E含量有逐渐降低的趋势,表现出一定的量效关系.推测芳香开窍中药冰片的药理作用方式可能通过调节中枢神经组织中单胺类神经递质含量达到稳态平衡有关.     

一种新来源天然冰片与合成冰片的致突变性比较研究

目的与方法采用鼠伤寒沙门氏菌回复突变试验(Ames试验),比较天然冰片与合成冰片的致突变作用.结果在标准平板掺入法试验中,天然冰片与合成冰片在0.4～250.0μg/皿范围内,无论有或无S9活化系统,对鼠伤寒沙门氏菌突变株(TA97、TA98、TA100、TA102)的回变菌落数均无明显影响,且回变菌落背景正常.结论新来源天然冰片与合成冰片在该实验室条件下均不具致突变效应.     

多元联系数在医院医疗质量综合评价排序中的应用

目的通过把多元联系数用于医院医疗质量综合评价排序的探讨,为医院医疗质量综合评价提供一种新的简便实用方法.方法根据评价对象个数m选用m元联系数,对m个评价对象的每个指标数据从优到劣编秩次从1到m,计算每个指标数据与该指标最优值的同一度,再根据秩次和m元联系数联系分量相对应的规则写出每个评价对象的m元联系数表达式,通过联系分量系数的取值把m元联系数转化为联系数值,根据联系数值的大小作出综合评价排序结论.结果利用m元联系数可以使综合评价计算过程简化,而评价和排序结果不变.结论可以在医院医疗质量综合评价排序中应用多元联系数.     

A Highly Specific and Sensitive Radioimmunoassay of Caerulein,An Analogue of Cholecystokinin-8

Abstract

A highly specific and sensitive competitive radioimmunoassay was developed for caerulein (CLN), an analogue of cholecystokinin-8 (CCK-8), in plasma and brain. Antiserum was produced in rabbit by immunization with Nδ-[CLN-(1-6)]-ornithine amide conjugated with bovine serum albumin by the glutaraldehyde method. Nα-[CLN-(1-6)]-lysine amide was labelled with ¹²⁵I-Bolton & Hunter reagent and used as a labelled antigen after purification by high-performance liquid chromerography. This assay was highly specific for CLN, and cross reactivities for other related peptides, CCK-4, CCK-8, gastrin-I, and gastrin-(14–17), were not observed (<0.01%). The limits of determination in biological specimens after CLN administration were 11 pg/ml in human plasma and rat plasma and 80 pg/g in rat brain. This study showed that the slight structure difference between hapten and ¹²⁵I-labelled antigen is important to the assay performance.     

Development of Conductive Boron-Doped Diamond Electrode: A microscopic,Spectroscopic, and Voltammetric Study

Building on diamond characteristics such as hardness, chemical inertness and low electron emission threshold voltage, the current microscopic, spectroscopic and voltammetric investigations are directed towards improving the properties of electrode coating materials for their future use in clinical studies of deep brain stimulation via fast-scan cyclic voltammetry (FSCV). In this study we combine the capabilities of confocal Raman mapping in providing detailed and accurate analysis of local distributions of material constituents in a series of boron-doped polycrystalline diamond films grown by chemical vapor deposition, with information from the more conventional techniques of scanning electron microscopy (SEM) and infrared absorption spectroscopy. Although SEM images show a uniform distribution of film crystallites, they have the limitation of being unable to differentiate the distribution of boron in the diamond. Values of 10¹⁸–10²¹ atoms/cm³ of boron content have been estimated from the absorption coefficient of the 1290 cm⁻¹ infrared absorption band and from the 500 cm⁻¹ Raman vibration. The observed accumulation of boron atoms and carbon sp² impurities at the grain boundaries suggests that very high doping levels do not necessarily contribute to improvement of the material’s conductivity, corroborating with voltammetric data. FSCV results also indicate an enhanced stability of analyte detection.     

Effect of Transmural Extent of the Simulated Infarction in a Left Ventricular Model on Displacement and Strain Distribution Estimated from Synthetic Ultrasonic Data

The identification of a sub-endocardial infarction is of major interest in cardiology. This study evaluates the sensitivity of selected measures to the thickness of such an infarction. Synthetic ultrasonic data (long-axis view) of left ventricular models with inclusions were generated using Field II and meshes obtained from finite-element simulations, which also provided the reference for the estimates obtained from ultrasonic data. The displacements, the first and second component of the principal strain (ε₁ and ε₂), and several measures derived from these quantities were estimated. All estimates, except for the poorly estimated ε₂, exhibited sensitivity to the presence and transmurality of the inclusion. The most sensitive was the gradient of the averaged transmural profiles of ε₁, and ε₁ averaged over the area corresponding to the transmural inclusion. The inflection point of the ε₁ profile shifted toward the outer wall with increasing thickness of the non-transmural inclusion.     

Wireless amplified NMR detector for improved visibility of image contrast in heterogeneous lesions

To demonstrate the capability of a wireless amplified NMR detector (WAND) to improve the visibility of lesion heterogeneity without the use of exogenous contrast agents, a cylindrically symmetric WAND was constructed to sensitively detect and simultaneously amplify MR signals emitted from adjacent tissues. Based on a two‐leg high‐pass birdcage coil design, this WAND could be activated by a pumping field aligned along the main field (B₀), without perturbing MR signal reception. Compared with an equivalent pair of external detectors, the WAND could achieve more than 10‐fold gain for immediately adjacent regions. Even for regions with 3.4 radius distance separation from the detector's cylindrical center, the WAND was at least 1.4 times more sensitive than an equivalent pair of surface arrays or at least twice as sensitive as a single‐sided external surface detector. When the WAND was inserted into a rat's rectum to observe adjacent tumors implanted beneath the mucosa, it could enhance the detection sensitivity of lesion regions, and thus enlarge the observable signal difference between heterogeneous tissues and clearly identify lesion boundaries as continuous lines in the intensity gradient profile. Hyperintense regions observable by the WAND existed due to higher levels of blood supply, which was indicated by a similar pattern of signal enhancement after contrast agent administration. By better observing the endogenous signal contrast, the endoluminal WAND could characterize lesions without the use of exogenous contrast agents, and thus reduce contrast‐induced toxicity.     

Supplementary values of the dosimetric parameters kNR and Em for various types of detectors in 6 and 15 MV photon fields

The present communication broadens the data base for determinations of the non-reference condition correction factor k_NR needed in high-energy photon dosimetry to accomplish the use of various detectors under non-reference conditions. Following our previous strategy of calculating semiempirical values of k_NR and correlating them with the mean photon energy E_m at the point of measurement in a large water phantom, the values of E_m are now stated for 6 and 15 MV photon radiations of accelerators with and without flattening filters, square field sizes from 1 to 30 cm side length and depths from 0 to 28 cm. The unambiguity of the k_NR-E_m correlation is again confirmed and is quantified by fitting formulae for air-filled ionization chambers, TLD detectors and Si diodes. This survey provides a practicable access to the k_NR values, particularly for the non-water equivalent detectors to be used in small-field dosimetry     

Increases in synthetic cannabinoids-related harms: Results from a longitudinal web-based content analysis

BackgroundSynthetic Cannabinoid Receptor Agonists (SCRA), also known as “K2” or “Spice,” have drawn considerable attention due to their potential of abuse and harmful consequences. More research is needed to understand user experiences of SCRA-related effects. We use semi-automated information processing techniques through eDrugTrends platform to examine SCRA-related effects and their variations through a longitudinal content analysis of web-forum data.MethodEnglish language posts from three drug-focused web-forums were extracted and analyzed between January 1st 2008 and September 30th 2015. Search terms are based on the Drug Use Ontology (DAO) created for this study (189 SCRA-related and 501 effect-related terms). EDrugTrends NLP-based text processing tools were used to extract posts mentioning SCRA and their effects. Generalized linear regression was used to fit restricted cubic spline functions of time to test whether the proportion of drug-related posts that mention SCRA (and no other drug) and the proportion of these “SCRA-only” posts that mention SCRA effects have changed over time, with an adjustment for multiple testing.Results19,052 SCRA-related posts (Bluelight (n = 2782), Forum A (n = 3882), and Forum B (n = 12,388)) posted by 2543 international users were extracted. The most frequently mentioned effects were “getting high” (44.0%), “hallucinations” (10.8%), and “anxiety” (10.2%). The frequency of SCRA-only posts declined steadily over the study period. The proportions of SCRA-only posts mentioning positive effects (e.g., “High” and “Euphoria”) steadily decreased, while the proportions of SCRA-only posts mentioning negative effects (e.g., “Anxiety,” ‘Nausea,” “Overdose”) increased over the same period.ConclusionThis study’s findings indicate that the proportion of negative effects mentioned in web forum posts and linked to SCRA has increased over time, suggesting that recent generations of SCRA generate more harms. This is also one of the first studies to conduct automated content analysis of web forum data related to illicit drug use.