Impact of Freeze–Thaw Cycles on the Long-Term Performance of Concrete Pavement and Related Improvement Measures: A Review

Freeze–thaw damage is one of the most severe threats to the long-term performance of concrete pavement in cold regions. Currently, the freeze–thaw deterioration mechanism of concrete pavement has not been fully understood. This study summarizes the significant findings of concrete pavement freeze–thaw durability performance, identifies existing knowledge gaps, and proposes future research needs. The concrete material deterioration mechanism under freeze–thaw cycles is first critically reviewed. Current deterioration theories mainly include the hydrostatic pressure hypothesis, osmolarity, and salt crystallization pressure hypothesis. The critical saturation degree has been proposed to depict the influence of internal saturation on freeze–thaw damage development. Meanwhile, the influence of pore solution salinity on freeze–thaw damage level has not been widely investigated. Additionally, the deterioration mechanism of the typical D-cracking that occurs in concrete pavement has not been fully understood. Following this, we investigate the coupling effect between freeze–thaw and other loading or environmental factors. It is found that external loading can accelerate the development of freeze–thaw damage, and the acceleration becomes more evident under higher stress levels. Further, deicing salts can interact with concrete during freeze–thaw cycles, generating internal pores or leading to crystalline expansion pressure. Specifically, freeze–thaw development can be mitigated under relatively low ion concentration due to increased frozen points. The interactive mechanism between external loading, environmental ions, and freeze–thaw cycles has not been fully understood. Finally, the mitigation protocols to enhance frost resistance of concrete pavement are reviewed. Besides the widely used air-entraining process, the freeze–thaw durability of concrete can also be enhanced by using fiber reinforcement, pozzolanic materials, surface strengthening, Super Absorbent Polymers (SAPs), and Phase Change Materials. This study serves as a solid base of information to understand how to enhance the freeze–thaw durability of concrete pavement.     

Prevention of Clostridium difficile infections—The role of vaccines and therapeutic immunoglobulins

Clostridium difficile is a spore-forming gram-positive bacterium that causes sometimes severe infections of the gut of affected individuals. The high prevalence of C. difficile infections has caused the Center for Disease Control to characterize this disease as “an immediate health threat that requires urgent and aggressive action.” A major issue with existing treatments for C. difficile is their reliance on antibiotics to kill the bacterium. These antibacterial agents cause disruptions in the gut flora that normally compete with C. difficile, rendering the gut lumen susceptible to a new round of infection or to germination of persistent C. difficile spores. This cycle of infection and recurrence underscores the need for novel approaches to the treatment and prevention of C. difficile infections. This review summarizes previous and ongoing efforts to develop active and passive immunization strategies for the prevention of primary and recurrent C. difficile infections.     

全面护理在鼻综合整形术的围手术期患者中的应用效果

目的 探究全面护理在鼻综合整形术的围手术期患者中的应用效果。方法 选取2020年 6月-2022年6月于我院行鼻综合整形术的53例患者为研究对象,按照随机数字表法分为传统组（n=27）和 探究组（n=26）。传统组采用常规护理,探究组采用全面护理,比较两组护理满意度及并发症发生情况。 结果 探究组护理满意度各维度评分均高于对照组（P＜0.05）;探究组并发症发生率为3.85%,低于对照 组的29.63%（P＜0.05）。结论 全面护理在鼻综合整形术的围手术期患者中的应用效果确切,可预防、减 少相关并发症发生,能够提升患者多层面的满意度,值得临床应用。     

不缩短指骨显微外科末节断指再植术的疗效观察

目的 研究不缩短指骨显微外科末节断指再植术的治疗效果。方法 选择2018年6月-2020年6月 我院收治的62例末节断指患者为研究对象,采用随机数字表法分为观察组和对照组,各31例。对照组实施 传统断指手术,观察组实施不缩短指骨显微外科末节断指再植术,比较两组手术效果、再植成活情况、疼 痛程度、生活质量、断指关节功能及并发症发生情况。结果 观察组手术优良率为96.77%,高于对照组 的77.42%（P ＜0.05）;观察组再植成活率为87.10%,高于对照组的58.06%（P ＜0.05）;观察组治疗后疼 痛评分低于对照组,生活质量评分高于对照组（P ＜0.05）;观察组治疗后断指关节功能评分高于对照组 （P＜0.05）;观察组并发症发生率为9.68%,低于对照组的32.26%（P＜0.05）。结论 不缩短指骨显微外科 末节断指再植术的疗效确切,再植成活率较高,可有效改善患者的指关节功能,减轻疼痛,有助于提高患 者的生活质量,且术后并发症较少,安全性较高,值得临床应用。     

异丙酚通过下调ERK-VEGF/MMP-9信号通路对肝癌细胞增殖、迁移及侵袭的影响及机制研究

目的 探讨异丙酚对人肝癌HepG2细胞增殖、迁移及侵袭多种生物学行为的影响及相关机制。方法用浓度递增的异丙酚（0μg/mL、5μg/mL、10μg/mL、20μg/mL）和二甲基亚砜（DMSO）处理HepG2细胞,然后采用体外细胞实验（CCK-8实验、划痕实验、Transwell侵袭实验）检测异丙酚对细胞增殖、迁移及侵袭能力的影响。Western blotting检测HepG2细胞中血管内皮生长因子（VEGF）、基质金属蛋白酶-9(MMP-9)、细胞外信号调节激酶（ERK）及p-ERK蛋白相对表达量。结果 CCK-8实验结果发现,与空白对照组比较,5μg/mL组、10μg/mL组及20μg/mL组HepG2细胞存活率逐渐降低（P <0.05）。划痕实验结果发现,异丙酚可以有效抑制HepG2细胞的迁移,且随着药物浓度增加细胞迁移能力逐渐减弱（P <0.05）。Transwell侵袭实验结果发现,异丙酚以一种浓度依赖的方式抑制HepG2细胞的侵袭能力（P <0.05）。Western blotting结果发现,异丙酚刺激可降低HepG2细胞中的VEGF、MMP-9及p-E...     

Protective effect of Juglanin against doxorubicin-induced cognitive impairment in rats: Effect on oxidative, inflammatory and apoptotic machineries

Metabolic Brain Disease - Doxorubicin (DOX) is an effective anticancer drug, however, side effects such as cognitive impairment and cardiotoxicity have limited its clinical use. Juglanin (JUG) is a...     

The efficacy of ultrasound-guided stellate ganglion block in alleviating postoperative pain and ventricular arrhythmias and its application prospects

Neurological Sciences - Stellate ganglion block (SGB) has been applied in clinic for almost a century as a therapeutic procedure to alleviate pain-related syndromes and vascular deficits in the...     

SARS-CoV-2-induced immunodysregulation and the need for higher clinical suspicion for co-infection and secondary infection in COVID-19 patients

Cases of co-infection and secondary infection emerging during the current Coronavirus Disease-19 (COVID-19) pandemic are a major public health concern. Such cases may result from immunodysregulation induced by the SARS-CoV-2 virus. Pandemic preparedness must include identification of disease natural history and common secondary infections to implement clinical solutions.     

Van der Waals heterostructures of SiC and Janus MSSe (M = Mo,W) monolayers: a first principles study

Favorable stacking patterns of two models with alternative orders of chalcogen atoms in SiC-MSSe (M = Mo, W) vdW heterostructures are investigated using density functional theory calculations. Both model-I and model-II of the SiC-MSSe (M = Mo, W) vdW heterostructures show type-II band alignment, while the spin orbit coupling effect causes considerable Rashba spin splitting. Furthermore, the plane-average electrostatic potential is also calculated to investigate the potential drops across the heterostructure and work function. The imaginary part of the dielectric function reveals that the first optical transition is dominated by excitons with high absorption in the visible region for both heterostructures. Appropriate band alignments with standard water redox potentials enable the capability of these heterostructures to dissociate water into H⁺/H₂ and O₂/H₂O.

Using DFT calculations, we have investigated the electronic structure, Rashba effect, optical and photocatalytic performance of SiC-MSSe (M = Mo, W) van der Waals heterostructures with different stacking patterns of chalcogen atoms.     

脑内铁沉积神经变性病临床特点及PLA2G6基因突变研究

目的探讨中国脑内铁沉积神经变性病(neurodegeneration with brain iron accumulation,NBIA)患者的临床特点及PLA2G6基因的突变特点。方法对3个NBIA家系、6个散发性NBIA患者的临床特点进行回顾性分析,应用聚合酶链反应(PCR)结合DNA直接序列分析方法,对NBIA患者进行PLA2G6基因突变研究。结果所有患者主要表现为锥体外系症状;头部MRI T2加权像表现双侧苍白球、黑质等部位对称性低信号,其中1家系在苍白球低信号区的前内侧出现高信号,即"虎眼征";本组NBIA患者未发现PLA2G6基因的致病突变,共发现7个多态,分别为c.C511T、c.G87A、IVS2+16C→T、IVS4+71A→G、IVS5+43C→T、IVS6+19G→A、和IVS15+55G→A,其中2个(c.C511T、IVS6+19G→A)为新发现的多态。结论根据临床和头部MRI特征可临床诊断NBIA,中国人NBIA患者PLA2G6基因突变可能罕见。