复方丹参注射液联合三维适形放疗同步化疗治疗局部晚期非小细胞肺癌

目的评价复方丹参注射液联合三维适形放疗（3DCRT）同步化疗治疗局部晚期非小细胞肺癌（NSCLC）的临床疗效和副作用。方法92例局部晚期NSCLC患者分为两组,其中丹参组43例采用复方丹参注射液联合三维适形放疗同步化疗．对照组49例采用三维适形放疗同步化疗,化疔采用多西他赛＋顺铂方案,化疗周期为6个周期。对两组临床疗效和不良反应进行评价。结果丹参组近期有效率为58．1％,中位生存期为18．25个月,对照组近期有效率为34．7％,中位生存期为13．93个月;丹参组放射性肺炎的发生率小于对照组,两组近期疗效和远期疗效差异均有统计学意义（P〈0．05）。结论复方丹参注射液可以提高晚期NSCLC的临床疗效,并减少放射性肺炎的发生率。     

Mask wearing in community settings reduces SARS-CoV-2 transmission

The effectiveness of mask wearing at controlling severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission has been unclear. While masks are known to substantially reduce disease transmission in healthcare settings [D. K. Chu et al., Lancet 395, 1973–1987 (2020); J. Howard et al., Proc. Natl. Acad. Sci. U.S.A. 118, e2014564118 (2021); Y. Cheng et al., Science eabg6296 (2021)], studies in community settings report inconsistent results [H. M. Ollila et al., medRxiv (2020); J. Brainard et al., Eurosurveillance 25, 2000725 (2020); T. Jefferson et al., Cochrane Database Syst. Rev. 11, {"type":"entrez-nucleotide","attrs":{"text":"CD006207","term_id":"30322945","term_text":"CD006207"}}CD006207 (2020)]. Most such studies focus on how masks impact transmission, by analyzing how effective government mask mandates are. However, we find that widespread voluntary mask wearing, and other data limitations, make mandate effectiveness a poor proxy for mask-wearing effectiveness. We directly analyze the effect of mask wearing on SARS-CoV-2 transmission, drawing on several datasets covering 92 regions on six continents, including the largest survey of wearing behavior (n= 20 million) [F. Kreuter et al., https://gisumd.github.io/COVID-19-API-Documentation (2020)]. Using a Bayesian hierarchical model, we estimate the effect of mask wearing on transmission, by linking reported wearing levels to reported cases in each region, while adjusting for mobility and nonpharmaceutical interventions (NPIs), such as bans on large gatherings. Our estimates imply that the mean observed level of mask wearing corresponds to a 19% decrease in the reproduction number R. We also assess the robustness of our results in 60 tests spanning 20 sensitivity analyses. In light of these results, policy makers can effectively reduce transmission by intervening to increase mask wearing.

Face masks are one of the most prominent interventions against COVID-19, with very high uptake in most countries (1). However, global mask wearing fell substantially in 2021, even in countries with low vaccination rates (Fig. 1). Given ongoing epidemics, establishing the effectiveness of mask wearing in community settings is critical. The following sections review past work on the effectiveness of mask wearing in different settings and at different scales.Open in a separate windowFig. 1.Reported mask wearing in countries with <40% of population fully vaccinated, as of 1 October 2021 [wearing from the UMD/Facebook survey (1); vaccinations from ref. 2]. The y axis is the proportion who reported that, over the last week, they wore masks most or all of the time in public spaces.In the context of healthcare, N95 masks (as defined by ref. 3) work well when worn properly by trained users—reducing transmission of coronaviruses including severe acute respiratory coronavirus syndrome 2 (SARS-CoV-2) by at least half (4, 5). Cheng et al. (6) find that ideal surgical masking (7, 8) of a noninfected person corresponds to a 65 to 75% reduction in their risk of COVID-19.However, the effect of mask wearing in small-scale community settings is more difficult to detect.In particular, four meta-analyses have summarized studies on respiratory infections, conducted in community settings (4, 9–11). They estimate mean decreases in infection risk between 4% and 15% for surgical masks, but with large uncertainty: Individual results ranged from a 7% increase in infection risk to a 61% decrease in infection risk. In addition, few of these studies are randomized controlled trials (RCTs), and those that are RCTs have considerable issues: Bungaard et al. (12) found a small, nonsignificant reduction in infection risk. Abaluck et al. (13), found a significant, 8.6% decrease in symptomatic seropositivity linked to mask wearing. However, limitations of the study included a requirement for unblinded participants to self-report symptoms before testing, use of an antibody test with a very low 5 d sensitivity, and unclear generalization from the specific context (rural villages in Bangladesh).We focus on the effects of mask wearing or mandates (i.e., legal requirements to wear a mask) on transmission in large connected populations. To study mask impacts on transmission, many studies use the timing of mask mandates as a proxy for sharp changes in the level of mask wearing. Some such studies have inferred limited or inconclusive effects in cross-country analyses (14) and within-country studies (15), while others find cross-country evidence that mask mandates and recommendations lead to decreased transmission and mortality (16, 17).Other analyses provide evidence for reduced case growth following subnational mandates within countries such as the United States (18–20) and Germany (21). A potential explanation for the inconsistency and uncertainty of these results is that data on national mandate timing may be poorly suited for analyzing the effects of mask wearing on transmission.Epidemiological studies often use government mask mandates as a proxy for mask wearing. However, the existing literature on the relationship between mandates and actual levels of mask wearing has shown surprisingly weak effects. For example, studying US states, ref. 22 failed to find a statistically significant relationship between mandates and subsequent wearing, while other studies found postmandate increases in wearing of just 13% (23) and 23% (24). Betsch et al. (25) find a ∼40% increase in wearing after local mandates in Germany, but no other study finds a comparably large increase. Given that the link between mandates and wearing is surprisingly weak, it is likely that the link between mandates and transmission is difficult to detect. Three additional factors lead us to suspect that a link between mandates and transmission would be difficult to detect. First, introducing a mandate is a coarse, one-off event that necessarily loses signal by not tracking day-to-day changes in mask wearing. We also have fewer data on mandates: Less than half of the regions we study enforced any mandate during the study period. Second, past studies treat mandates as a binary on/off intervention that is fully implemented at a single point in time. However, modeling the effect of mandates as an instantaneous change in the reproduction number or mortality fails to capture changes in wearing behavior following the announcement of a mandate but before its enforcement (21). Nor does it account for gradual change in behavior after the implementation of a mandate. Finally, the circumstances of mandate policies are highly heterogeneous, both in terms of the preexisting level of voluntary wearing at the time of implementation and in terms of how exactly they are defined, enforced, and complied with. Consequently, averaging the international effect of mandates based on coarse data is unlikely to provide a useful summary of heterogeneous mandate effects. Importantly, these arguments point to the link between mandates and transmission being difficult to detect, not that it is absent.Because of these difficulties in studying the effect of mandates, we instead focus on estimating the effect of mask wearing on transmission, using a large (n = 19.97 million) global survey of self-reported mask wearing (1). Two other studies estimate mask effectiveness from self-reports: In their study of 24 countries, Aravindakshan et al. (26) use YouGov wearing data to infer an overall 3.9 to 10% relative decrease in case growth rate from whole population mask wearing. Rader et al. (22) study US states using a novel SurveyMonkey wearing dataset to infer a ∼10% decrease in transmission between the lowest and highest empirical quartiles of wearing (a 50 to 75% increase in wearing). Rader et al. use data limited to 12 US states during June–July 2020. Our data are richer: We study 56 countries on six continents, and our inferential analyses span May–September 2020.Our analysis goes further than past work in the quality of wearing data—100 times the sample size, with random sampling and poststratification—the geographical scope, the use of a semimechanistic infection model, the incorporation of uncertainty into epidemiological parameters, and the robustness of our results (59 sensitivity tests). See

X射线行李包安检设备辐射泄漏量的MCNP模拟

目的 模拟计算地铁站所使用的X射线行李包安检设备辐射泄漏量的大小。方法 采用MCNP4C程序来模拟X射线安检设备在使用过程中X射线的泄漏量。结果 人体接受到的最大辐射剂量为8.26μSv/a,但如果能保持安检设备铅帘的完整性人体受到的辐射剂量仅为0.0727μSv/a。结论 当行李进出安检机并导致铅帘产生缝隙时,辐射泄漏量会显著增大;人体所受到的最大辐射量仍低于《电离辐射防护与辐射源安全基本标准》(GB18871-2002)中规定的10μSv/a的豁免标准。     

新型喉罩在腹腔镜盆腔肿瘤切除术麻醉中的应用

探讨新型喉罩（NLMA）在腹腔镜盆腔肿瘤切除术麻醉中的可行性.采用弹性树脂探条引导法置入NLMA,记录NLMA置入前即刻、置入后1、3、5和10 min及气腹后5、10、20和30 min时收缩压（SP）、舒张压（DP）、心率（HR）,呼气末二氧化碳分压（PETCO2）和脉搏血氧饱和度（SpO2）变化,同时观察NLMA通气罩在不充气、充气10、20和30 mL时,分别在气道压20、30和40 cm H2O水平,患者处于头正中位、屈曲位、过伸位和侧位的气道密封效果.NLMA置管成功率100%,血液动力学、PETCO2及SpO2稳定（P＞0.05）,喉罩气囊不充气,气道压20 cmH2O时,76.5%～77.9%不漏气;充气30 mL气道压低于30 cmH2O时,91.8%～97.5%不漏气,气道压40 cmH2O时,5例少量漏气.各种头位不影响气道密闭效果.95.6%患者胃管1次置入成功,纤支镜证实NLMA位置好,术后无不良反应.初步结果提示,NLMA可安全用于腹腔镜盆腔肿瘤切除术.     

白头翁皂苷B4调控去乙酰化酶6对胃癌细胞转移和放疗敏感性的影响

目的 探讨白头翁皂苷B4(AB4)对胃癌细胞增殖、迁移、侵袭及放疗敏感性的影响及其分子机制。方法 该研究起止时间为2018年4月至2019年10月。体外培养人正常胃黏膜上皮细胞GES-1与胃癌细胞HGC-27,采用不同浓度（25、50、100μmol/L）的AB4处理24 h,通过MTT法检测细胞存活率并筛选AB4适宜浓度用于后续研究。Transwell实验检测HGC-27细胞迁移及侵袭能力。细胞克隆形成实验检测AB4对HGC-27细胞放射敏感性的影响;蛋白质印迹法检测AB4对HGC-27细胞中去乙酰化酶6(SIRT6)蛋白表达的影响;干扰SIRT6表达联合AB4处理后,采用上述检测方法检测HGC-27细胞增殖、迁移、侵袭及放射敏感性;蛋白质印迹法检测DNA激活蛋白激酶催化亚基（DNA-PKcs）、DNA双链修复蛋白Rad51、DNA修复酶Ku80、基质金属蛋白酶-2(MMP-2)、基质金属蛋白酶-9(MMP-9)蛋白表达水平。结果 与NC组相比,AB4处理后HGC-27细胞存活率[（100.01±9.57）%比（86.57±6.58）%、（65.45±8.45）%、（49.58±7....     

CBCT影像组学联合构建Nomogram模型预测食管癌放疗患者放射性肺炎

目的:通过对放疗疗程中不同时段CBCT图像的影像组学分析,寻找早期定量预测食管癌放疗放射性肺炎(RP)的参数,结合临床特征和肺剂量体积参数建立联合Nomogram模型并探讨这一模型对食管癌RP的预测价值。方法:回顾分析2017—2019年间临床资料、剂量学参数、CBCT图像资料完整的96例胸中段食管鳞癌调强放疗患者资料...     

MRI在鼻咽癌放射治疗中的应用研究

目的探讨MRI在鼻咽癌诊治中的应用价值。方法分析经病理证实的245例鼻咽癌患者的MRI和CT影像学资料。结果MRI对鼻咽癌超腔、咽旁间隙、口咽、咽后淋巴结、颅底骨质、海绵窦等侵犯的检出率明旺高于CT,差异有统计学意义（P〈0．05）;MRI与CT对鼻咽癌鼻腔侵犯和颈部淋巴结转移检出率差别无统计学意义（P〉0．05）。结论MRI能够清晰显示鼻咽癌肿块、邻近结构和咽后淋巴结转移等,对鼻咽癌的诊断和治疗具有重要价值。     

64层MSCT冠状动脉成像低剂量扫描的临床探讨

目的探讨64层MSCT冠状动脉成像（CTcoronary angiography,CTCA）在固定噪声水平低剂量扫描中的临床应用。方法将连续行CTCA检查患者60例分为两组,回顾性分析30例作为固定mA组,随后采用前瞻性分析30例作为个体mA组,比较两组图像质量、噪声、CT剂量指数（CTDIvol）及有效剂量（effectivedose,ED）的差异。结果两组图像质量评分及噪声差异无统计学意义（P〉0.05）,个体mA组CTDIvol、ED分别为（99.29±9.04）mGy和（28.10±2.73）mSv,较固定mA组分别减少了10.64%、15.03%（P〈0.01）。结论 64层MSCT冠脉成像在固定噪声水平个性化调节mA的方法,可有效地减少辐射剂量。     

电缆辐照加工企业职业危害及防护调查

目的通过对电缆辐照加工技术职业危害的调查分析和检测,明确电缆辐照加工的职业危害种类和防护重点,并提出职业危害防护策略。方法选取1家应用辐照加工技术生产电缆的企业为研究对象,通过职业卫生调查、职业危害含放射危害的检测、职业健康检查等方法开展研究。结果电缆辐照技术生产应用中存在多种职业危害,包括辐射危害为电子束和X线,化学性危害为臭氧、氮氧化物及六氟化硫等,物理性危害为噪声。职业防护中对辐照场所合理布局与分区、开展机房与辐照厅屏蔽防护设计、设置人身安全联锁及机器安全联锁,化学性危害防护中对辐照大厅全面通风,防止有害气体蓄积,是主要的职业危害防护措施。结论电缆辐照等辐照加工技术使用日益广泛,认真开展企业职业危害防护特别是辐照安全防护,可保证辐照加工作业人员的职业安全。