Molecular simulations of gas transport in hydrogenated nitrile butadiene rubber and ethylene–propylene–diene rubber

Diffusion and sorption of five gases (H₂, N₂, O₂, CO₂, CH₄) in hydrogenated nitrile butadiene rubber (HNBR) and ethylene–propylene–diene rubber (EPDM) have been investigated by molecular dynamics (MD) and grand canonical Monte Carlo (GCMC) simulations. The diffusion coefficients of gas molecules in HNBR and EPDM are well correlated with the effective penetrant diameter except for CO₂. CO₂ shows a lower diffusion coefficient due to its linear shape. Additionally, the favorable interaction between CO₂ and HNBR is another factor for its lower diffusion coefficient in HNBR. HNBR shows lower diffusion coefficients than EPDM. This is because the polar –CN groups in HNBR chains increase interchain cohesion and result in tight intermolecular packing, low free volume and poor chain mobility, which decreases the diffusion coefficients of HNBR. The solubility coefficients of CH₄, O₂, N₂ and H₂ in HNBR are lower than those in EPDM, which is a result of the weak HNBR–penetrant interactions and low free volume of HNBR. However, the solubility coefficient of CO₂ in HNBR is higher than in EPDM. This is attributed to the strong interaction between CO₂ and HNBR. H₂, O₂, N₂ and CH₄ show lower permeability coefficients in HNBR than in EPDM, while CO₂ has higher permeability coefficients in HNBR. These molecular details provide critical information for the understanding of structures and gas transport between HNBR and EPDM.

Diffusion and sorption of five gases (H₂, N₂, O₂, CO₂, CH₄) in HNBR and EPDM were explored by MD and GCMC simulations.     

Outcome of laparoscopic colectomy for cancer in elderly patients

Background

Resection for colon cancer in the elderly is a major undertaking. However, data on the outcome and survival of elderly patients who underwent laparoscopic resection for colon cancer are limited. This study of patients older than 75 years compared outcome and survival between those who underwent laparoscopic resection and those who had open resection for colorectal cancer.

Methods

From 2000 to 2009, 434 patients ages 75 years and older who underwent elective resection for colon cancer were included in the study. Patients who had rectal cancer or had undergone emergency operations were excluded. Preoperative diagnosis was determined by colonoscopy, and computed tomography scan was performed for preoperative staging. Data on the patients’ demographics, operative details, pathology results, postoperative results, and survival were collected prospectively. The patients who underwent laparoscopic surgery were compared with those who had open surgery.

Results

The study included 434 patients (210 men) with a median age of 80 years (range 75–95 years). Of these 434 patients, 189 underwent laparoscopic resection. Nine patients (4.8 %) required conversion to open operation. The patients did not differ in terms of age, gender, incidence of medical comorbidities, or stage of disease. The median operating time was longer in the laparoscopic group, but the blood loss was significantly less. Laparoscopic resection was associated with a lower mortality rate and a shorter hospital stay (p < 0.05). The open resection group had significantly more cardiac complications (p < 0.05). The overall 5-year survival rates were similar between the patients who had laparoscopic resections and those who had open surgery.

Conclusions

For patients older than 75 years, laparoscopic resection of colon is associated with less intraoperative blood loss, a shorter hospital stay, fewer cardiac complication, and a lower mortality rate than open resection. Therefore, the authors recommend laparoscopic resection of colon cancer as the treatment of choice for elderly patients.     

Association Between Lipid Profiles and Left Ventricular Hypertrophy: New Evidence from a Retrospective Study

ObjectiveTo explore the association between lipid profiles and left ventricular hypertrophy in a Chinese general population.MethodsWe conducted a retrospective observational study to investigate the relationship between lipid markers [including triglycerides, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein (HDL) cholesterol, non-HDL-cholesterol, apolipoprotein A-I, apolipoprotein B, lipoprotein[a], and composite lipid profiles] and left ventricular hypertrophy. A total of 309,400 participants of two populations (one from Beijing and another from nationwide) who underwent physical examinations at different health management centers between 2009 and 2018 in China were included in the cross-sectional study. 7,475 participants who had multiple physical examinations and initially did not have left ventricular hypertrophy constituted a longitudinal cohort to analyze the association between lipid markers and the new-onset of left ventricular hypertrophy. Left ventricular hypertrophy was measured by echocardiography and defined as an end-diastolic thickness of the interventricular septum or left ventricle posterior wall > 11 mm. The Logistic regression model was used in the cross-sectional study. Cox model and Cox model with restricted cubic splines were used in the longitudinal cohort.ResultsIn the cross-sectional study, for participants in the highest tertile of each lipid marker compared to the respective lowest, triglycerides [odds ratio (OR): 1.250, 95%CI: 1.060 to 1.474], HDL-cholesterol (OR: 0.780, 95%CI: 0.662 to 0.918), and lipoprotein(a) (OR: 1.311, 95%CI: 1.115 to 1.541) had an association with left ventricular hypertrophy. In the longitudinal cohort, for participants in the highest tertile of each lipid marker at the baseline compared to the respective lowest, triglycerides [hazard ratio (HR): 3.277, 95%CI: 1.720 to 6.244], HDL-cholesterol (HR: 0.516, 95%CI: 0.283 to 0.940), non-HDL-cholesterol (HR: 2.309, 95%CI: 1.296 to 4.112), apolipoprotein B (HR: 2.244, 95%CI: 1.251 to 4.032) showed an association with new-onset left ventricular hypertrophy. In the Cox model with forward stepwise selection, triglycerides were the only lipid markers entered into the final model.ConclusionLipids levels, especially triglycerides, are associated with left ventricular hypertrophy. Controlling triglycerides level potentiate to be a strategy in harnessing cardiac remodeling but deserve to be further investigated.     

四磨汤口服液对脾虚便秘小鼠肠黏膜结构的影响

目的探讨四磨汤口服液对脾虚便秘小鼠肠黏膜结构损伤的修复作用。方法通过灌胃番泻叶水煎液7 d,控制饮食、饥饱失常8 d建立小鼠脾虚便秘模型,造模成功后,治疗组给予四磨汤口服液灌胃,治疗5 d,模型组和正常组给予等量无菌水灌胃,取肠道组织进行病理切片观察。结果四磨汤能修复损伤的空肠、回肠黏膜结构,减轻炎症细胞浸润,且能增加盲肠的杯状细胞数目。结论四磨汤口服液治疗脾虚便秘,其作用可能与修复小鼠肠黏膜结构相关。     

Clioquinol and vitamin B12 (cobalamin) synergistically rescue the lead-induced impairments of synaptic plasticity in hippocampal dentate gyrus area of the anesthetized rats in vivo

Lead (Pb(2+)) exposure in development induces impairments of synaptic plasticity in the hippocampal dentate gyrus (DG) area of the anesthetized rats in vivo. The common chelating agents have many adverse effects and are incapable of alleviating lead-induced neurotoxicity. Recently, CQ, clioquinol (5-chloro-7-iodo-8-hydroxy-quinoline), which is a transition metal ion chelator and/or ionophore with low affinity for metal ions, has yielded some promising results in animal models and clinical trials related to dysfunctions of metal ions. In addition, CQ-associated side effects are believed to be overcome with vitamin B12 (VB12) supplementation. To determine whether CQ treatment could rescue impairments of synaptic plasticity induced by chronic Pb(2+) exposure, we investigated the input/output functions (I/Os), paired-pulse reactions (PPRs) and long-term potentiation (LTP) of different treatment groups in hippocampal DG area of the anesthetized rat in vivo by recording field potentials and measured hippocampal Pb(2+) concentrations of different treatment groups by PlasmaQuad 3 inductive coupled plasma mass spectroscopy. The results show: CQ alone does not rescue the lead-induced impairments of synaptic plasticity in hippocampal DG area of the anesthetized rats in vivo; VB12 alone partly rescues the lead-induced impairments of LTP; however the co-administration of CQ and VB12 totally rescues these impairments of synaptic plasticity and moreover, the effects of CQ and VB12 co-administration are specific to the lead-exposed animals.     

Limitations of polymerase chain reaction testing for diagnosing acute Epstein-Barr virus infections

Clinicians use molecular tests to detect Herpesviridae from blood without fully appreciating limitations of testing. Studies are needed to enhance our understanding of the impact of Herpesviridae latency on molecular testing. We retrospectively performed quantitative Epstein-Barr virus (EBV) on sera from patients between the ages of 1 and 30 who demonstrated serologic evidence of acute EBV (n = 50) or remote EBV (n = 50) infection. Epstein-Barr virus DNA was detected in 70% of acutely infected and 4% of remotely infected patients. Sera from acutely infected patients had higher EBV copy number than convalescent sera. Our results suggest that serology should be performed as the initial diagnostic test for acute EBV. The role for polymerase chain reaction in immunocompromised patients with impaired antibody responses or as a 2nd-line diagnostic test when serologic results are equivocal deserves further study.     

床上体操配合音乐疗法对脑卒中患者早期肢体功能影响

目的研究床上体操配合音疗对脑卒中早期患者偏瘫肢体功能的影响.方法将100例脑卒中偏瘫患者分为2组,常规组(n=50),常规+训练组(n=50).常规组给予常规内科治疗护理.常规+训练组除常规内科治疗护理外,根据患者肢体运动功能情况选择适合不同时期的床上体操和音疗训练,治疗前后予Brunnstrom法运动功能评估,日常生活活动能力Barthel指数评估,心理评估.结果治疗前2组日常生活活动能力、肢体运动功能、心理评估无差异,治疗后1个月常规+训练组日常生活活动能力(Barthel指数)、运动功能(Brunnstrom法)明显高于常规组(P＜0.05).常规+训练组的恐怖、抑郁、强迫、焦虑症状得到明显改善(P＜0.05).常规组治疗护理组抑郁、强迫、焦虑症状无明显改善(P＞0.05),仅恐怖症状有改善(P＜0.05).结论音乐床上体操对脑卒中早期偏瘫肢体功能恢复和心理障碍治疗有明显作用,有利于提高患者的生活质量.     

大鼠股骨开放截骨模型与闭合骨折模型制作的比较

背景:骨折动物模型无疑是研究骨折愈合的基石,其中开放截骨模型与闭合骨折模型是较成熟的两种长骨干骨折模型.就作者所查文献,未见芙于大鼠两种模型比较研究的报道.目的:比较人鼠股骨开放截骨模型与闭合骨折模型的制作过程,并通过X射线摄片比较二者的骨折愈合情况.设计、时间及地点:随机对照动物实验,于2007-01/05在苏州大学附属第二医院骨科实验室完成.材料:SPF级雄性SD大鼠40只,体质量(220±30)g,随机分为开放截骨模型组与闭合骨折模型组,每组20只.电动摆锯;自行改良设计的闭合骨折模型打击器.方法:开放组行开放截骨术造成股骨中段横行骨折,逆行克氏针固定:闭合组行逆行克氏针固后,使用造模支架致股骨中段闭合骨折.主要观察指标:比较两组的平均造模时间,造模成功率及术后2,3,4,8周骨折愈合的X射线情况.结果:开放截骨模型每只造模成功率90%,平均造摸时间为17 min,骨折畸形愈合及不愈合率40%;闭合骨折模型每只造模成功率85%,平均造模时间12 min,未见畸形愈合及不愈合.术后2,3,4周X射线评分开放组均低于闭合组(P＜0.05),8周时开放组X射线评分仍较闭合组低,但差异无显著性意义(P＞0.05).结论:开放截骨模型造模时间长,骨折畸形愈合不愈合发生率高,近中期骨折愈合明显滞后,不适于近中期骨折愈合的研究.     

术前超声检测胆囊周围粘连的方法及其临床价值

目的 探讨术前超声判断胆囊周围有无粘连的方法，观察指标及对预测腹腔镜手术难度的临床价值。方法 采用自身对照研究方案，选择2003年6月～2003年9月间我院26例因胆囊结石拟行腹腔镜胆囊切除术的患。通过超声观察胆囊与肝脏、胆囊周围肠管及脐孔处腹膜与肠管有无错位滑动，判定有无胆囊周围粘连，并在手术中验证。结果 (1)超声检测出12例胆囊与周围肠管或网膜发生粘连，其中1例误诊，另有1例漏诊，本组病例中超声判定胆囊周围肠管粘连的敏感性与特异性均为91．7％，假阳性与假阴性均为8．3％；(2)超声仅见1例脐孔处粘连，并经手术证实；(3)超声及手术均未见胆囊与肝脏发生粘连。结论 通过超声观察胆囊与其周围脏器间有无错位滑动判断胆囊周围有无粘连，是一种简便易行，结果可靠的预测腹腔镜手术难度的方法之一，它能帮助手术医师正确估价手术难度，合理选择病例和手术方式。     

幽门螺杆菌耐药性测定及其机制的初步探讨

用７种抗生素对４４株临床分离的幽门螺杆菌（Ｈ．ｐ）进行耐药性研究，并对其中１９株Ｈ．ｐ进行质粒检测，发现Ｈ．ｐ对氨苄青霉素及痢特灵敏感，对庆大，氟哌酸等５种抗生不同程度耐药现象，质粒检出率为３１．６％，质粒与本试验所用抗菌素耐药性无关，研究还发现亚抑菌浓度抗生素可引起Ｈ．ｐ发生球形变，本文对Ｈ．ｐ的球形变现象及其与耐药性关系进行探讨。