Residence time modeling of hot melt extrusion processes

The hot melt extrusion process is a widespread technique to mix viscous melts. The residence time of material in the process frequently determines the product properties. An experimental setup and a corresponding mathematical model were developed to evaluate residence time and residence time distribution in twin screw extrusion processes.The extrusion process was modeled as the convolution of a mass transport process described by a Gaussian probability function, and a mixing process represented by an exponential function. The residence time of the extrusion process was determined by introducing a tracer at the extruder inlet and measuring the tracer concentration at the die. These concentrations were fitted to the residence time model, and an adequate correlation was found. Different parameters were derived to characterize the extrusion process including the dead time, the apparent mixing volume, and a transport related axial mixing. A 2³ design of experiments was performed to evaluate the effect of powder feed rate, screw speed, and melt viscosity of the material on the residence time. All three parameters affect the residence time of material in the extruder.In conclusion, a residence time model was developed to interpret experimental data and to get insights into the hot melt extrusion process.     

Seasonal variations in HbA1c among type 2 diabetes patients on a semi-arid climate between the years 2005–2015

AimsTo investigate the seasonal variations of HbA1c values in a semi-arid climate among type 2 diabetic patients throughout 11 years of care.MethodsA retrospective cohort study of 2860 patients with 61,187 HbA1c measures. We calculated the averages of HbA1c values of all patients and sub-groups defined by age, gender, BMI, ethnicity, insulin use, smoking status and region of residence, matched to the mean temperature and diurnal range over the 30 and 60 days prior to the HbA1c test date.ResultsWe found a sinusoidal seasonal pattern with statistically significant HbA1c levels gaps between the spring peak and the autumn trough (F = 18.4, P < 0.001). The lowest values were in October-November and the highest in March or August with a difference of 0.17–0.31% (2–4 mmol/mol). We found different relations between the mean temperature and HbA1c depending on season, gender, age, ethnicity and smoking habits.ConclusionThe study identified specific subgroups in which the seasonal influence is particularly marked. A possible explanation is that during hot periods people tend to change their diet and decrease their physical activity, effecting indirectly diabetic imbalance. Recognition of the seasonal variations of HbA1c levels in this geographical region could help physicians with diabetes care and HbA1c control.     

Crime displacement in digital drug markets

Background Crackdowns on urban sites with concentrated criminal activity are sometimes followed by geographical relocation of crime. Is this also the case in cyberspace, where illegal websites and online networks can be wiped clean, but also quickly rebuilt and replaced on new servers and URLs?Methods I address this question in three steps. First, I measure MDMA trade in a large digital market for drugs, before and after the arrest of a leading MDMA seller in the same market. Second, I count the number of available digital drug markets and vendor shops in the period February 2014–June 2018, to see if websites closed by police were replaced by new ones. Third, I track the digital movement and trading activities of individual drug sellers, before and after law enforcement shut down two large markets.Results After police arrested a leading MDMA seller, other MDMA sellers filled most – but not all – of the gap. A major law enforcement crackdown reduced the number of available markets, but new ones were created, and market counts eventually surpassed the previous peak. When law enforcement shut down two big markets, many of the sellers relocated to other e-commerce sites and continued high-earning operations there.Conclusion Arrests and market closures redirect digital drug trade to other sellers and markets. Hot spot policing in cyberspace might produce temporary results, but is arguably ineffective in the long run, as actors use information and communication technology’s unique capacities to reorganize.     

Self-compassion weakens the association between hot flushes and night sweats and daily life functioning and depression

Objectives

Some women find hot flushes and night sweats (HFNS) to interfere more in daily life and mood than others. Psychological resources may help to explain these individual differences. The aim of this study was to investigate the role of self-compassion, defined as healthy way of relating toward the self when dealing with difficult experiences, as a potential moderator of the relationship between HFNS and daily life activities, which in turn influences symptoms of depression.

Study design

This was a cross-sectional study using questionnaire data from 206 women aged 40–60 who were currently experiencing hot flushes and/or night sweats. Path analysis was used to model relationships among menopausal factors (HFNS frequency and daily interference ratings), self-compassion and mood.

Main outcome measure

Hot flush interference in daily activities and depressive symptoms.

Results

On average, women experienced 4.02 HFNS per day, and HFNS frequency was moderately correlated with interference ratings (r = 0.38). In the path analytic model, self-compassion made significant direct contribution to hot flush interference ratings (β = −0.37) and symptoms of depression (β = −0.42), and higher self-compassion was associated with lower interference and depressive symptoms. Self-compassion also moderated the relationship between HFNS frequency and hot flush interference. Higher self-compassion was associated with weaker effects of HFNS frequency on daily interference.

Conclusions

Self-compassion may weaken the association between HFNS and daily life functioning, which in turn, could lead to less HFNS-related mood problems. These findings imply that self-compassion may be a resilience factor to help women manage hot flushes and night sweats.     

术前闪光视网膜电图振荡电位对2型糖尿病患者眼底病变和白内障术后视力的评价

目的: 评价2型糖尿病白内障患者术前闪光视网膜电图振荡电位波幅和潜伏期与眼底病变和术后视力恢复程度的关系.方法: 选择75例2型糖尿病白内障患者,在白内障囊外摘除人工晶体植入术前行闪光视网膜电图振荡电位总波振幅及其子波的波幅和潜伏期测定,术后行眼底检查、矫正视力测定,比较患者术前OPs各子波振幅、潜伏期、OPs总波振幅与术后眼底所见、视力恢复之间的关系,并与对照组比较.结果: 术前OPs各子波、OPs总波振幅与眼底病变和白内障术后视力恢复程度明显相关.结论: 术前振荡电位中OPs总波,子波OPs1～4的波幅的降低程度可以在一定程度上预测2型糖尿病白内障患者眼底视网膜病变的程度和视力恢复程度,潜伏期的检测意义不如振幅.     

更年期妇女潮热的健康教育

目的探讨临床上在治疗更年期妇女潮热的同时进行健康教育指导的临床意义．方法将60例更年期妇女潮热的患者随机分成两组，健康教育组通过发放宣传小手册、举行健康教育讲座，让患者了解“潮热”发生的原因、治疗方法、治疗中的注意事项及治疗依从性对疗效的影响．并比较两组患者服药的依从性及疗效的差别．结果健康教育组对更年期妇女潮热的认知度高于对照组，两组比较P〈0．05．健康教育组病人服药依从性比对照组好，两组病人潮热治疗效果有显著性差异．结论对更年期妇女潮热的患者进行健康知识教育是非常必要的，它有利于提高患者对疾病的认知率，提高服药的依从性，缓解症状、改善生活质量，有着十分重要的意义．     

黄芪皂苷甲的镇痛、镇静作用

本文证实给小鼠黄芪皂苷甲后出现镇痛作用,其镇痛作用较度冷丁弱而短。根据对小鼠腹腔注射醋酸产生扭体反应抑制率测得静脉注射黄芪皂苷甲的ED50为47.8±3.4mg/kg;由热板法测得的ED50为25.4±1.5mg/kg。黄芪皂苷甲也能明显延长硫喷妥钠所致小鼠的麻醉时间。此外,黄芪皂苷甲还能使豚鼠离体回肠张力下降。