Optical Bandgap Definition via a Modified Form of Urbach’s Rule

We are reporting an esoteric method to determine the optical bandgap of direct gap materials by employing Urbach’s rule. The latter, which describes the slope of the band tail absorption in semiconductors, in its original version, cannot be employed to pinpoint the optical bandgap. Herein, however, we show that a modified form of Urbach’s rule defines the optical bandgap, and therefore, enables the accurate determination of the optical bandgap energy, which turns out to be identical with the threshold energy for the band tail absorption. The model further produces an explicit expression for the absorption coefficient at the optical bandgap energy.     

Underuse of Clinical Decision Rules and d-Dimer in Suspected Pulmonary Embolism: A Nationwide Survey of the Veterans Administration Healthcare System

PurposeThe diagnosis of pulmonary embolism (PE) remains a challenge. CT pulmonary angiography (CTPA) for suspected PE has become the primary imaging modality, but concerns regarding overutilization, overdiagnosis, radiation, and costs have led to algorithms that combine a clinical decision rule (CDR) and highly sensitive d-dimer to identify patients in whom PE can be safely excluded without further studies. This has been identified as a top five Choosing Wisely recommendation in pulmonary medicine, but adherence is modest at best and actual utilization is unknown. Therefore, a survey was conducted to determine the prevalence of this approach in the Veterans Administration (VA) healthcare system.MethodsA web-based questionnaire survey (SurveyGizmo.com) was developed and validated to query the utilization of CDR ± d-dimer in suspected PE. Key stakeholders identified from national VA mailing lists of radiology, pulmonary, and emergency medicine chiefs were sent an email describing the survey and provided a link for response. This study was reviewed and approved by our local institutional review board and accessing the link represented consent for participation. No personally identifiable data were collected and a drawing for a gift card was provided as an incentive.ResultsThere were a total of 159 responses, with 120 fully completed surveys for analysis. The majority of respondents were chiefs (63%) with 11+ years of experience (80%), from hospitals with house staff (86%) and an emergency department (97%). Respondents were from emergency medicine (31%), pulmonary (27%), radiology (26%), and other departments (9%). The overwhelming majority of respondents (85%) did not require results of a CDR ± d-dimer before ordering a CTPA. Only 6.7% required a CDR + d-dimer, with others requiring either only a CDR (5.8%) or d-dimer (2.5%). The most common CDR was the Wells score, with only one using the Pulmonary Embolism Rule-Out Criteria. Nine of 18 (50%) regional Veterans Integrated Service Networks reported at least one site requiring a CDR before CTPA. An average of 9.6 CTPAs were estimated to be performed per week. Sorted by CDR and d-dimer use, 8 (CDR + d-dimer), 6.9 (CDR only), 8 (d-dimer only), 10.1 (no requirements) CTPA studies were performed weekly. The average CTPA yield for PE was estimated at 11.9% (CDR + d-dimer), 8% (CDR only), 2.5% (d-dimer only), and 7.6% (no requirements).ConclusionsThe vast majority of hospitals within the VA system do not use a CDR ± d-dimer in the evaluation of patients with suspected PE. Utilization of a CDR and d-dimer may decrease CTPA utilization and increase yield, but this assessment is limited by the scope of the survey.Clinical ImplicationsCDR-guided strategies are recommended in the evaluation of suspected PE. Adherence within the VA healthcare system is very low. Further investigation is warranted to better characterize and improve the adherence to CDR-guided strategies and CTPA utilization.     

The HIT Expert Probability (HEP) Score: a novel pre‐test probability model for heparin‐induced thrombocytopenia based on broad expert opinion

Summary. Background: The diagnosis of heparin‐induced thrombocytopenia (HIT) is challenging. Over‐diagnosis and over‐treatment are common. Objectives: To develop a pre‐test clinical scoring model for HIT based on broad expert opinion that may be useful in guiding clinical decisions regarding therapy. Patients/methods: A pre‐test model, the HIT Expert Probability (HEP) Score, was constructed based on the opinions of 26 HIT experts. Fifty patients referred to a reference laboratory for HIT testing comprised the validation cohort. Two hematology trainees scored each patient using the HEP Score and a previously published clinical scoring system (4 T’s). A panel of three independent experts adjudicated the 50 patients and rendered a diagnosis of HIT likely or unlikely. All subjects underwent HIT laboratory testing with a polyspecific HIT ELISA and serotonin release assay (SRA). Results: The HEP Score exhibited significantly greater interobserver agreement [intraclass correlation coefficient: 0.88 (95% CI 0.80–0.93) vs. 0.71 (0.54–0.83)], correlation with the results of HIT laboratory testing and concordance with the diagnosis of the expert panel (area under receiver‐operating curve: 0.91 vs. 0.74, P = 0.017) than the 4 T’s. The model was 100% sensitive and 60% specific for determining the presence of HIT as defined by the expert panel and would have allowed for a 41% reduction in the number of patients receiving a direct thrombin inhibitor (DTI). Conclusion: The HEP Score is the first pre‐test clinical scoring model for HIT based on broad expert opinion, exhibited favorable operating characteristics and may permit clinicians to confidently reduce use of alternative anticoagulants. Prospective multicenter validation is warranted.     

试论“针道自然”

众所周知,中医理论的形成直接受中国古代哲学思想的影响,特别是道家思想。顺其势而治的思想提示我们在针灸临床诊治过程中,一是顺生理特性,二是顺病证特性,在顺自然之势而治的思想指导下,去洞悉和贯通诸多针灸原则与方法,从而达到心领神会,运用自如,以取得针灸治疗的最佳效果。     

External validation of the clinical indications of computed tomography (CT) of the head in patients with low-energy geriatric hip fractures

IntroductionOn evaluation of the clinical indications of computed tomography (CT) scan of head in the patients with low-energy geriatric hip fractures, Maniar et al. identified physical evidence of head injury, new onset confusion, and Glasgow Coma Scale (GCS) < 15 as predictive risk factors for acute findings on CT scan. The goal of the present study was to validate these three criteria as predictive risk factors for a larger population in a wider geographical distribution.Patients and methodsPatients ≥65 years of age with low-energy hip fractures from 6 trauma centers in a wide geographical distribution in the United States were included in this study. In addition to the relevant patient demographic findings, the above mentioned three criteria and acute findings on head CT scan were gathered as categorical variables.ResultsIn total 799 patients from 6 centers were included in the study. There were 67 patients (8.3%) with positive acute findings on head CT scan. All of these patients (100%) had at least one criteria positive. There were 732 patients who had negative acute findings on head CT scan with 376 patients (51%) having at least one criteria positive and 356 patients (49%) having no criteria positive. Sensitivity of 100% and negative predictive value of 100% was observed to predict negative acute findings on head CT scan when all the three criteria were negative.ConclusionWith the observed 100% sensitivity and 100% negative predictive value, physical evidence of acute head injury, acute retrograde amnesia, and GCS < 15 can be recommended as a clinical decision guide for the selective use of head CT scans in geriatric patients with low energy hip fractures. All the patients with positive acute head CT findings can be predicted in the presence of at least one positive criterion. In addition, if these criteria are used as a pre-requisite to order the head CT, around 50% of the unnecessary head CT scans can be avoided.     

月经病针灸治疗取穴规律探讨

月经病治疗可以从调和气血、调补脏腑和调理冲任三方面入手,以足三阴和任督经脉腧穴为主,常用腧穴为太冲、太溪、三阴交、血海、阴陵泉、足三里、气海、关元、百会等。     

中医辨证治疗慢性萎缩性胃炎配伍用药规律分析

目的:通过文献分析,初步总结中医辨证治疗慢性萎缩性胃炎(Chronic Atrophic Gastnritis,CAG)配伍用药规律。方法:检索1994-2006年中医辨证治疗CAG相关文献,提取证候类型、辨证用药等信息,建立数据库并进行统计分析。结果:CAG脾胃虚弱证治疗以益气健脾药为主,常与温里药、理气药、活血药和养阴药组合配伍;肝胃不和证以疏肝理气药与活血药、养阴药组合配伍最多见;脾胃湿热证以化湿药与理气药、健脾益气药之间的配伍最多见;胃阴不足证中养阴药主要与理气药、活血药、和胃消导药组合配伍;胃络瘀血证组方以活血化瘀药为主,常配伍理气药、益气健脾药和养阴药。结论:辨证治疗CAG用药有一定的规律可循,多在主方、主药的基础上,综合考虑本证型病机特点,适当配伍其他类药物,或使其兼顾病机更加广泛,提高主药治疗效果,或防止主药作用太过,佐制其潜在副作用,充分体现了中医治病从整体出发,重视辨证论治的思想。     

正交试验研究珍珠草的人工种植技术

目的研究在人工栽培条件下,珍珠草的种植方法、生长条件、生长规律,探讨大面积人工栽培的可能性,为总结珍珠草的GAP技术打下基础。方法采用种子繁育和人工移栽相结合的方法,比较野生与家种,人工栽培、种子种植与幼苗移栽种植等的生长规律、生长条件、产量等。结果在人工栽培条件下,珍珠草的各项指标均优于野生;采用种子繁育与人工移栽相结合的栽培方法明显优于单纯种子种植。结论广东省云浮地区适合珍珠草的人工种植,栽培试验成功。     

粗银针恢刺治疗脊柱过敏症临床研究

目的:探寻治疗脊柱过敏症的有效疗法。方法:将45例患者分为治疗组(24例)和对照组(21例)。对照组常规毫针取阿是穴、夹脊穴治疗;治疗组采用粗银针恢刺督脉经阿是穴。观察两组患者疼痛及相关兼症的缓解情况。结果:治疗组治愈率75%,有效率95%;对照组治愈率38%,有效率66.7%;两组治愈率、有效率比较差异有显著意义(P<0.01),结论:粗银针恢刺治疗脊柱过敏症的疗效优于常规毫针治疗组。     

基于小波变换和似然无偏估计的胃阻抗信号处理研究

目的：介绍一种基于小波变换和似然无偏估计的胃阻抗信号分析去噪的方法。方法：首先经过多分辨分析将信号进行分离，然后应用Stein似然无偏估计对胃阻抗信号进行自适应软阈值去噪处理。结果：实验结果表明，该方法能够有效滤除由呼吸、血流阻抗等因素造成的干扰。结论：小波分析技术为进一步研究胃动力信号的参数分析提供了新途径。