Upper-lower solutions for nonlinear parabolic systems and their applications

The method of upper-lower solutions for nonlinear parabolic systems without the assumption of quasi-monotonicity is obtained. An application is provided, by using the method developed in this paper, involving the existence of positive solutions to certain time-dependent interaction systems arising in biological and medical sciences. Furthermore, the existence of the ω-limit of given system is studied.     

轮状病毒感染性腹泻患儿的微量元素锌检测结果分析

目的：检测轮状病毒感染性腹泻患儿的全血微量元素锌的水平,探讨轮状病毒感染性腹泻患儿全血微量元素锌的变化。方法对186例轮状病毒感染性腹泻患儿和675例健康对照组儿童进行全血微量元素锌测定。结果轮状病毒感染性腹泻患儿全血微量元素锌含量明显低于健康对照组儿童,差异有统计学意义（ P＜0.05）。结论轮状病毒感染性腹泻患儿全血微量元素锌水平明显下降,需要及时补充微量元素锌。     

Adaptive Flexible Sialylated Nanogels as Highly Potent Influenza A Virus Inhibitors

Flexible multivalent 3D nanosystems that can deform and adapt onto the virus surface via specific ligand–receptor multivalent interactions can efficiently block virus adhesion onto the cell. We here report on the synthesis of a 250 nm sized flexible sialylated nanogel that adapts onto the influenza A virus (IAV) surface via multivalent binding of its sialic acid (SA) residues with hemagglutinin spike proteins on the virus surface. We could demonstrate that the high flexibility of sialylated nanogel improves IAV inhibition by 400 times as compared to a rigid sialylated nanogel in the hemagglutination inhibition assay. The flexible sialylated nanogel efficiently inhibits the influenza A/X31 (H3N2) infection with IC₅₀ values in low picomolar concentrations and also blocks the virus entry into MDCK‐II cells.     

Quantifying the strength and durability of induced immunity to HIV infection in women engaging in unprotected sexual contacts with infected men

Evidence is accumulating that exposure to human immunodeficiency virus (HIV) can lead to an increased resistance or immunity to subsequent infection. A multirisk model that permits either induced immunity or infection to develop after heterosexual inoculation with HIV is shown to be compatible with a wide spectrum of disparate male-to-female transmission data.When the model is applied to time-dependent, HIV-seroprevalence data, the probability that an unexposed woman would remain unexposed after an unprotected contact with an infected man was estimated to be greater than 0.95 on the average. Thus, it would require at least 14 unprotected sexual contacts with HIV-infected men for 50% of an unexposed cohort of women to become exposed to the virus. This suggests that there is a low probability that HIV virions will be found to have penetrated the mucosal barriers of the reproductive tract after a contact.The model also predicts, that the average woman whose mucosal barriers have been breached by HIV has a significant probability of developing immunity to the virus rather than infection. Modelling data for a cohort of unexposed Nairobi women leads to the prediction that the probability of acquiring induced immunity per contact is about 60% of the probability of acquiring the disease per contact.The modelling results also predict that those who had developed resistance to HIV run the small, but significant risk of becoming infected nonetheless by continuing high-risk behavior. For the common contact rate of ten per month, the modelling predicts that the HIV-transmission risk per contact for unexposed women in the Nairobi cohort is 1/178 while the transmission risk for the cohort's immunized women is 1/1548. These numbers suggest that HIV infection is difficult to transmit through heterosexual intercourse on the average and that male-to-female HIV-transmission risk per contact for African women lies between 1/178 and 1/1548.Direct confirmation of the predictions in the last paragraph has been subsequently observed in two completely independent studies. The Nairobi research team recently reported that a notable number of Nairobi prostitutes previously identified to be members of the HIV-resistant group became infected nonetheless. Second, in a study of 174 sexually monogamous, discordant couples in Rakai, Uganda reporting contacts rates of nine to ten per month, the male-to-female HIV-transmission risk per contact was found to be 1/769 by direct measurement, a value that falls between the above limits of 1/178 and 1/1548 predicted by the modelling. Thus, a second major prediction of this paper has been directly confirmed, and induced immunity to HIV is limited and not absolutely protective.Circumstantial evidence suggests that the induced immunity to HIV predicted by the model could be generated and/or initiated by nonspecific innate immune responses, specific immunological responses, including IgA-mediated mucosal immunity and cytotoxic T lymphocytes (CTL) immunity, or some combination of the above. It is suggested here, that a decrease in the ability of HIV virions to penetrate the protective mucus layer of the reproductive tract may be a prerequisite, cofactor, or the principle cause of the induced immunity or resistance demonstrated to exist in this paper. The value of the probability that induced immunity to HIV will develop after a contact is shown to be a sensitive function of the woman's human leucocyte antigen (HLA) supertype profile.     

持续静脉泵入及分次静点给予特治星治疗下呼吸道感染的效果观察

目的研究持续静脉泵入及分次静点给予特治星治疗下呼吸道感染的效果。方法选择116例下呼吸道感染患者,随机分为两组,观察组给予持续静脉泵入特治星治疗方案,对照组给予分次静脉点滴特治星治疗方案,治疗1周后观察治疗效果和安全性。结果观察组总有效率为94.83%显著高于对照组84.48%(P0.05),不良反应发生率为6.9%显著低于对照组20.69%(P0.05)。两组治疗后体温(T)、白细胞(WBC)及C反应蛋白(CRP)水平较治疗前均显著降低,观察组降低更为显著(P0.05)。两组治疗后氧分压(Pa O2)水平较治疗前均显著升高,观察组升高更为显著(P0.05)。结论持续静脉泵入能显著提高下呼吸道感染患者总有效率,降低不良反应发生率。     

研究中心集中式管理模式在供应室控制医院感染管理中的效果分析

目的探讨中心集中式管理模式在消毒供应中心控制医院感染管理中的效果。方法随机采集2013年1月至2013年12月期间消毒供应中心相关资料作为对照组,2014年1月至2014年12月期间消毒供应中心相关资料作为研究组,比较两组手术器械清洗合格率、手术器械消毒灭菌合格率、医院感染率、医护人员卫生合格率、手术台卫生合格率、手术服卫生合格率与物品卫生合格率的差异。结果两组临床指标的比较结果显示,手术器械清洗合格率、手术器械消毒灭菌合格率、医护人员卫生合格率、手术台卫生合格率、手术服卫生合格率与物品卫生合格率明显高于对照组,两组比较差异具有统计学意义(P0.05),观察组医院感染率明显低于对照组,两组比较差异具有统计学意义(P0.05)。结论中心集中式管理模式在消毒供应中心控制医院感染管理中的效果显著,有助于显著降低医院感染率,提高手术器械与卫生物品合格率。     

降钙素原在指导慢性阻塞性肺疾病急性加重期抗感染治疗中的价值

目的观察并分析降钙素原在指导慢性阻塞性肺疾病急性加重期抗感染治疗中的价值。方法研究对象选取2015年5月期间来湖北省宜昌市第二人民医院就诊的100例慢性阻塞性肺疾病急性加重期病例,根据随机数字表法将其分为对照组与观察组各50例,对照组结合临床实际情况制订抗生素治疗方案,观察组则根据血清降钙素原(PCT)指导抗生素应用,对比两组抗生素应用时间、临床治疗效果、住院时间、病情加重与死亡率,并对研究结果相关数据作统计学处理。结果与对照组比,观察组抗生素使用时间、住院时间更短,组间差异显著而具有统计学意义(P0.05);两组临床治疗效果,病情加重率与死亡率差异并无统计学意义(P0.05)。结论在慢性阻塞性肺疾病急性加重期,监测血清降钙素原水平以指导抗感染治疗可有效降低抗生素使用量,促进患者康复,具有积极的临床意义。     

Chitosan-Based Hydrogels for Infected Wound Treatment

Wound infections slow down the healing process and lead to complications such as septicemia, osteomyelitis, and even death. Although traditional methods relying on antibiotics are effective in controlling infection, they have led to the emergence of antibiotic-resistant bacteria. Hydrogels with antimicrobial function become a viable option for reducing bacterial colonization and infection while also accelerating healing processes. Chitosan is extensively developed as antibacterial wound dressings due to its unique biochemical properties and inherent antibacterial activity. In this review, the recent research progress of chitosan-based hydrogels for infected wound treatment, including the fabrication methods, antibacterial mechanisms, antibacterial performance, wound healing efficacy, etc., is summarized. A concise assessment of current limitations and future trends is presented.     

The effect of solvent composition on vancomycin hydrochloride and free base vancomycin release from in situ forming implants

In situ forming drug delivery systems that are formed by solvent‐induced phase inversion have attracted extensive attention in sustained delivery of peptides and proteins. Based on the findings of our previous studies, N‐methyl‐2‐pyrrolidone (NMP) and acetone are two solvents that could improve the release profile of vancomycin from in situ forming systems based on poly(D,L‐lactide‐co‐glycolic acid). In this study, the effect of different compositions of these solvents on the release profile of hydrochloride and free base forms of vancomycin was investigated. To this end, several formulations with vancomycin (either hydrochloride or free base form) and different proportions of NMP and acetone were prepared. The cumulative drug release at specified time was determined and tested against conventional kinetic models. The surface and cross‐sectional morphology of implants were investigated by SEM. The experimental results showed that as solvent composition changed, the amount of vancomycin release during the first 12 h changed, too. The use of free base vancomycin resulted in an extended vancomycin release profile with less initial burst release. The formulation containing free base vancomycin and mixed solvents of acetone and NMP in 2:1 ratio released 70% of loaded drug in 6 weeks with near zero‐order kinetic. The best kinetic model to fit the in vitro release profiles was found to be Peppas–Sahlin model. Copyright © 2016 John Wiley & Sons, Ltd.