The occurrence of antimicrobial substances in toilet,sink and shower drainpipes of clinical units: A neglected source of antibiotic residues

Antibiotics represent one of the most important drug groups used in the management of bacterial infections in humans and animals. Due to the increasing problem of antibiotic resistance, assurance of the antibacterial effectiveness of these substances has moved into the focus of public health. The reduction in antibiotic residues in wastewater and the environment may play a decisive role in the development of increasing rates of antibiotic resistance. The present study examines the wastewater of 31 patient rooms of various German clinics for possible residues of antibiotics, as well as the wastewater of five private households as a reference.To the best of our knowledge, this study shows for the first time that in hospitals with high antibiotic consumption rates, residues of these drugs can be regularly detected in toilets, sink siphons and shower drains at concentrations ranging from 0.02?μg·L^?1 to a maximum of 79?mg·L^?1. After complete flushing of the wastewater siphons, antibiotics are no longer detectable, but after temporal stagnation, the concentration of the active substances in the water phases of respective siphons increases again, suggesting that antibiotics persist through the washing process in biofilms. This study demonstrates that clinical wastewater systems offer further possibilities for the optimization of antibiotic resistance surveillance.     

Associations between periodontal disease and selected risk factors of early complications among youth with type 1 and type 2 diabetes: a pilot study

Merchant AT, Jethwani M, Choi Y‐H, Morrato EH, Liese AD, Mayer‐Davis E. Associations between periodontal disease and selected risk factors of early complications among youth with type 1 and type 2 diabetes: a pilot study. Background: Most studies evaluating the relation between periodontal disease and diabetes in children have not considered diabetes type. Objective: To evaluate the relationship between periodontal damage and risk factors of diabetes complications among youth by diabetes type in a pilot study. Subjects: 155 participants (126 with type 1 diabetes; 29 with type 2 diabetes) from the SEARCH for Diabetes in Youth study in South Carolina who were <20 yr of age at diagnosis. Methods: Cross‐sectional analysis of periodontal damage (bone loss ≥3 mm on ≥1 permanent tooth site on pre‐existing bitewing radiographs) and diabetes type assigned by the provider at diagnosis. Results: Periodontal damage was observed in 52 individuals (34%) overall, but was more common in type 2 (16/29, 55%) vs. type 1 diabetes (37/126, 29%). Among youth with type 2 diabetes, those with periodontal damage had lower fasting c‐peptide (2.3 vs. 3.4 ng/mL, p‐value = 0.01), and higher triglyceride levels (171.8 vs. 87.2, p‐value = 0.01) than those without periodontal damage after adjustment for age, sex, race, education level, family income, duration of diabetes, diabetes control, time between study visit and date of radiograph, tooth brushing, and visits to the dentist. Blood pressure, waist circumference, LDL cholesterol and A1c were not associated with periodontal damage. Conclusions: The associations between periodontal disease and risk factors for diabetes complications differ by diabetes type. Periodontal damage is associated with impaired beta cell function and metabolic syndrome components in type 2 but not type 1 diabetes. These findings need to be confirmed in larger, prospective studies.     

Multi-frequency auditory stimulation disrupts spindling activity in anesthetized animals

It is often implied that during the occurrence of spindle oscillations, thalamocortical neurons do not respond to signals from the outside world. Since recording of sound-evoked activity from cat auditory cortex is common during spindling this implies that sound stimulation changes the spindle-related brain state. Local field potentials and multi-unit activity recorded from cat primary auditory cortex under ketamine anesthesia during successive silence-stimulus-silence conditions were used to investigate the effect of sound on cortical spindle oscillations. Multi-frequency stimulation suppresses spindle waves, as shown by the decrease of spectral power within the spindle frequency range during stimulation as compared with the previous silent period. We show that the percentage suppression is independent of the power of the spindle waves during silence, and that the suppression of spindle power occurs very fast after stimulus onset. The global inter-spindle rhythm was not disturbed during stimulation. Spectrotemporal and correlation analysis revealed that beta waves (15-26 Hz), and to a lesser extent delta waves, were modulated by the same inter-spindle rhythm as spindle oscillations. The suppression of spindle power during stimulation had no effect on the spatial correlation of spindle waves. Firing rates increased under stimulation and spectro-temporal receptive fields could reliably be obtained. The possible mechanism of suppression of spindle waves is discussed and it is suggested that suppression likely occurs through activity of the specific auditory pathway.     

Biliary atresia recent insight

Biliary atresia (BA) is a rare disease characterized by ascending obstruction of bile ducts that exclusively affects newborn infants. The etiology of the disease is not known. BA is considered to be a phenotype resulting from several pathogenic processes leading to obstruction of the biliary tree. It usually presents shortly after birth, characterized by persistent jaundice, hepatosplenomegaly, clay-colored stool, and dark urine. It affects both the extra-hepatic biliary ducts (EHBDs) and the intra-hepatic biliary system (IHBDs), but the former is more severely affected. Diagnosis of BA is a great challenge and must be achieved as early as possible to delay progression to cirrhosis. Laboratory tests reveal direct hyperbilirubinemia and, variable levels of transaminases, gamma-glutamyl transpeptidase (GGT), and alkaline phosphatase (ALP), which overlap significantly with other causes of neonatal cholestasis. The intraoperative cholangiogram is considered the gold standard for the diagnosis of BA and is performed routinely in many institutions. BA can be divided into correctable and non-correctable types; the former accounts for (10–15%) of cases, in which the proximal common hepatic duct is patent, allowing primary anastomosis of the EHBDs to the bowel. All patients are subjected to identical surgical and medical treatments; consisting of Kasai portoenterostomy (KPE), which entails removal of the atretic extra-hepatic tissue and a Roux-en-Y jejunal loop anastomosed to the hepatic hilum. Kasai portoenterstomy is considered a transition to liver transplantation, as the pathology may be still ongoing. BA is the most frequent indication for liver transplantation in infants, which is the only treatment that can definitively arrest the natural disease course. In conclusion: BA is a serious liver disease that needs to be further studied, and awareness of BA should be increased among the public and health care workers to prevent the complications of this disease.     

染料木素和大豆苷元对去卵巢大鼠胆固醇代谢的影响

目的　观察大豆异黄酮的两种主要苷元染料木素(Gen)和大豆苷元 (Dai)对去卵巢大鼠胆固醇代谢的影响。方法　Wistar大鼠 70只 ,随机分成正常组、模型组、雌激素组、大剂量G组、小剂量G组、大剂量D组、小剂量D组 ,每组 10只。除正常组外 ,其余各组均切除双侧卵巢。术后 1wk开始给药 ,给药 6wk后处死动物 ,测定血清总胆固醇(sTC)、血清低密度脂蛋白胆固醇 (LDL C)、血清高密度脂蛋白胆固醇 (HDL C)、肝组织中胆固醇 (hTC)含量。结果　切除卵巢 7wk后大鼠sTC ,LDL C ,hTC均增高。雌激素可降低去卵巢大鼠sTC、LDL C和hTC ,对HDL C作用不明显 ;染料木素可降低sTC、hTC、升高HDL C ,但对LDL C作用不明显 ;大豆苷元可降低sTC、hTC、LDL C ,但对HDL C作用不明显。结论　染料木素和大豆苷元均可降低去卵巢大鼠sTC和hTC水平 ,但作用途径不同 ;作用效果大豆苷元优于染料木素     

医用钛合金模拟体液预浸后的疲劳性能及其数值模拟

目的 研究新型低弹模Ti-3Zr-2Sn-3Mo-25Nb（TLM）钛合金在模拟体液（simulated body fluid,SBF）干预下的腐蚀疲劳性能。方法 以Ti-6Al-4V（TC4）钛合金为对照组,测定两种钛合金在SBF中的电化学腐蚀极化曲线,并对预腐蚀后的TC4钛合金和TLM钛合金试样进行旋转弯曲疲劳试验,利用实验数据建立加载应力幅与疲劳断裂循环次数之间的关系,绘制应力-寿命曲线,通过分析试样的腐蚀疲劳微观断口形貌分析其断裂机制,并结合有限元软件对钛合金试件进行疲劳分析。结果 应力退火状态下TC4钛合金自腐蚀电位低于热处理后的TLM钛合金,而TLM钛合金对循环应力的变化更为敏感。对比仿真结果与试验结果显示,应力退火状态下的TC4钛合金与热处理后的TLM钛合金相比疲劳强度更高,抵抗裂纹扩展的能力更强,而耐腐蚀性能反之。相对于未预腐蚀处理试件,SBF预浸泡后的TLM钛合金脆性增加,疲劳性能有所降低。结论 通过对比分析,说明试验结果可靠性高,COMSOL有限元软件能够很好预测钛合金材料的疲劳寿命。     

Dynamic Mechanical Properties of TC11 Titanium Alloys Fabricated by Wire Arc Additive Manufacturing

To study the compressive mechanical properties and failure modes of TC11 titanium alloy fabricated by wire arc additive manufacturing (WAAM) technology in a large strain rate range at room temperature, the quasi-static and dynamic compression tests were carried out. In addition, optical microscopy (OM) and scanning electron microscopy (SEM) were employed to observe the metallographic structure and fracture morphology, respectively. The stress–strain curves in the range of 0.001 s⁻¹–4000 s⁻¹, original and post-deformation microstructures, macroscopic damage patterns, and microscopic fracture morphology were obtained at two different loading directions, including the scanning and deposition directions, respectively. In uniaxial compression experiments, the material showed little difference in mechanical properties between the scanning and deposition directions, exhibiting a strain rate strengthening effect. However, the strain rate sensitivity of the material under quasi-static loading conditions is much less than that under dynamic loading conditions. In addition, combining the stress–strain curve with the fracture morphology analysis, the plasticity in the scanning direction is better than in the deposition direction. Based on the experimental results, a modified Johnson–Cook (JC) constitutive model considering strain rate sensitivity and the effect of strain rate on strain hardening was proposed, and the parameters were determined using a Multiple Population Genetic Algorithm (MPGA). The obtained constitutive model is in good agreement with the experimental data, which can provide a reference for the engineering numerical calculation of TC11 titanium alloy for WAAM. This study also provides a fundamental databank for the application and design of WAAM TC11 alloy in the manufacturing of large and complex structural parts.     

肟菌酯原药致突变毒性研究

目的 探讨肟菌酯的致突变性,预测其遗传危害和潜在致癌作用. 方法 分别按照GB15670-1995《农药登记毒理学试验方法》、GB/T 21793-2008《化学品体外哺乳动物细胞基因突变试验方法》、GB/T 21794-2008《化学品体外哺乳动物细胞染色体畸变试验方法》进行试验. 结果 微核试验、体外哺乳动物细胞染色体畸变试验和体外哺乳动物TK基因突变试验结果显示,肟菌酯原药各剂量组与溶剂对照组比较,差异无统计学意义（P＞0.05）;Ames试验结果显示各菌株的各测试浓度的回复突变菌落数均未超过自发回复突变菌落数的2倍. 结论 在本试验条件下,肟菌酯原药无致突变性.     

Corrosion–Resistance Mechanism of TC4 Titanium Alloy under Different Stress-Loading Conditions

Titanium alloys have now become the first choice of tubing material used in the harsh oil- and gas-exploitation environment, while the interaction of force and medium is a serious threat to the safety and reliability of titanium alloy in service. In this paper, different stresses were applied to TC4 titanium alloy by four-point bending stress fixture, and the corrosion behavior of TC4 titanium alloy was studied by high-temperature and high-pressure simulation experiments and electrochemical techniques, and the microscopic morphologies and chemical composition of the surface film layer on the specimen were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), to reveal the corrosion-resistance mechanism of TC4 titanium alloy under different stress-loading conditions. The results showed that the pits appeared on the specimens loaded with elastic stress, but the degree of pitting corrosion was still lighter, and the surface film layer showed n-type semiconductor properties with cation selective permeability. While the pits on the specimens loaded with plastic stress were deeper and wider in size, and the semiconductor type of the surface film layer changed to p-type, it was easier for anions such as Cl⁻ and CO₃²⁻ to adsorb on, destroy, and pass through the protective film and then to contact with the matrix, resulting in a decrease in corrosion resistance of TC4 titanium alloy.