Gravitational demand on the neck musculature during tablet computer use

Tablet computer use requires substantial head and neck flexion, which is a risk factor for neck pain. The goal of this study was to evaluate the biomechanics of the head–neck system during seated tablet computer use under a variety of conditions. A physiologically relevant variable, gravitational demand (the ratio of gravitational moment due to the weight of the head to maximal muscle moment capacity), was estimated using a musculoskeletal model incorporating subject-specific size and intervertebral postures from radiographs. Gravitational demand in postures adopted during tablet computer use was 3–5 times that of the neutral posture, with the lowest demand when the tablet was in a high propped position. Moreover, the estimated gravitational demand could be correlated to head and neck postural measures (0.48 < R ² < 0.64, p < 0.001). These findings provide quantitative data about mechanical requirements on the neck musculature during tablet computer use and are important for developing ergonomics guidelines.

Practitioner Summary: Flexed head and neck postures occur during tablet computer use and are implicated in neck pain. The mechanical demand on the neck muscles was estimated to increase 3–5 times during seated tablet computer use versus seated neutral posture, with the lowest demand in a high propped tablet position but few differences in other conditions.     

Strategic demand forecasts for the tablet PC market using the Bayesian mixed logit model and market share simulations

Since the release of the Apple iPad and the explosion of consumer demand for tablet PCs, a number of companies are entering into the tablet PC market, creating a situation that is becoming more fiercely competitive, complex, and difficult to predict. Under the singularity of the Korean tablet PC market, into which both the iPad and Galaxy Tab (with an Android operating system) were simultaneously released, this study closely analyses consumer preferences for tablet PCs. It uses the Bayesian mixed logit model, which can reflect consumers’ heterogeneous preferences based on data collected from a conjoint method, and using the estimates of the consumer utility function with model verification, it offers forecasts for the tablet PC market under six likely situations.     

紫外-可见漫反射光谱-支持向量回归法快速测定西咪替丁片剂含量

采用紫外-可见漫反射光谱-支持向量回归法（UV-Vis DRS-SVR）建立了快速、无损测定西咪替丁片剂的定量方法。人工配制58个西咪替丁片剂粉末样,分为校正集和预测集。经过光谱预处理、异常值剔除和参数优化,最终采用原始光谱,在220.17 nm-980.80 nm,参数g=0.02, C=20, p=0.03的条件下,建立SVR模型,校正集和预测集的决定系数（R2）分别为0.9782, 0.9871,对5个盲样和15个批次市售西咪替丁片剂的预测均方根差（RMSEP）分别为0.0360, 0.0448,比PLS模型的预测精度更高,效果更好。研究表明,UV-Vis DRS-SVR用于快速、非破坏性测定药物制剂中的活性成分是可行的,有望用于制剂生产过程中的质量控制。     

双氯芬酸钠缓释片的制备和体外释放度研究

以氢化蓖麻油为骨架材料,乳糖为致孔剂,湿法制粒制备双氯芬酸钠缓释片,并进行体外释放度和稳定性考察。结果表明:该缓释片符合缓释片现行质量标准要求且稳定性较好。     

过程能力指数在粉末直压工艺研究中的应用

摘 要：目的 研究普通型微晶纤维素及102型微晶纤维素对粉末直接压片的B族维生素片片重稳定性的影响,选出最适合制备B族维生素片的微晶纤维素应用方案。方法：以可衡量片重稳定性的过程能力指数为主要评价指标,关联压片压力、脆碎度及崩解时间为辅助评价指标,分别考察普通型微晶纤维素、102型微晶纤维素及两者以不同比例组合使用时制备B族维生素片的工艺顺应性。结果 在粉末直接压片中,普通型微晶纤维素及102型微晶纤维对B族维生素片的压片压力、脆碎度及崩解的影响差异较小;102型微晶纤维素的片重稳定性明显优于普通型微晶纤维素,但两者以3：1的比例组合使用,是最适合的使用方案。结论 在粉末直接压片的工艺研究中,借助过程能力指数,可获得较高性价比的工艺配方。     

铀矿地浸井场自动巡回检测装置的研制与应用

研制了用于铀矿地浸井场集控室多路生产井浸出液取样和铀浓度、pH、ORP等参数测量的自动巡回检测装置。该装置在内蒙某铀矿山酸法地浸井场的现场试验表明,整套装置运行稳定,可实现自动取样和测量,测量结果符合要求。     

丽江玛卡片和秘鲁玛卡片营养成分对比分析和评价

目的：将丽江玛卡片与秘鲁玛卡片的营养成分进行分析,观察两种片剂在营养价值上的异同。方法：采用国标方法测定两种片剂中的蛋白质、氨基酸、脂肪、脂肪酸、粗纤维、维生素和10种矿物质等营养成分含量并进行比较。结果：两种片剂在营养组成和含量上基本相似,但丽江玛卡片在脂肪、铁元素含量上明显低于秘鲁,而在精氨酸含量和不饱和脂肪酸相对含量上高于秘鲁玛卡片。结论：玛卡具有较高的营养价值,可以进一步引种和开发该资源。     

石膏板护面纸起沟纸病的处理

纸面石膏板是以建筑石膏为主要原料,掺入适量添加剂与纤维做板芯,以特制的纸板为护面,经加工制成的板材,是一种质轻、具有一定强度和良好防火、隔热、隔音、抗震性能的弹性板材.生产1m2纸面石膏板约需要石膏板护面纸0.5k g,由石膏板护面纸影响纸面石膏板板面质量的原因有板面起沟,板面搓皮、起毛,板面分层、起泡,纸与石膏粘接不牢,成纸强度低,跑边、荷叶边等,本文主要叙述石膏板护面纸起沟纸病在生产过程中的控制.     

Application of similarity factor in development of controlled-release diltiazem tablet

Controlled-release grade hydroxypropylmethylcellulose (HPMC) or xanthan gum (XG) and microcrystalline cellulose (MCC) were employed to prepare controlled-release diltiazem hydrochloride tablets. The similarity factor f₂ was used for dissolution profile comparison using Herbesser 90 SR as a reference product. Drug release could be sustained in a predictable manner by modifying the content of HPMC or XG. Moreover, the drug release profiles of tablets prepared using these matrix materials were not affected by pH and agitation rate. The f₂ values showed that only one batch of tablets (of diltiazem HCl, HPMC or XG, and MCC in proportions of 3.0:3.0:4.0) was considered similar to that of the reference product, with values above 50. The unbiased similarity factor f^*₂ values were not much different from the f₂ values, ascribing to a small dissolution variance of the test and reference products. The amount of HPMC or XG incorporated to produce tablets with the desired dissolution profile could be determined from the curves of f₂ versus polymer content. Hence, the f₂ values can be applied as screening and optimization tools during development of controlled-release preparations.     

强效丹参片的研制和体外溶出度

采用淀粉作填充剂和崩解剂,滑石粉作润滑剂制备强效效丹参片,并研究了强效丹参片体外溶出度,通过TLC法和UV法分别检出丹参酮ⅡA和测定阿斯匹林的含量,结果表明：本品在人工胃液中60min的溶出试验数据用Weibull分布直线方程拟合,线性关系良好,所有片剂在45min内均可溶解80％以上,本品处方较合理,制备工艺较简单,体外溶出试验符合药典对片剂溶出度的规定。