The effect of jet lag on the human brain: A neuroimaging study

Jet lag is commonly experienced when travelers cross multiple time zones, leaving the wake–sleep cycle and intrinsic biological “clocks” out of synchrony with the current environment. The effect of jet lag on intrinsic cortical function remains unclear. Twenty‐two healthy individuals experiencing west‐to‐east jet lag flight were recruited. Brain structural and functional magnetic resonance studies, as well as psychological and neurohormonal tests, were carried out when participants returned from travel over six time zones and 50 days later when their jet lag symptoms had resolved. During jet lag, the functional brain network exhibited a small‐world topology that was shifted toward regularity. Alterations during jet lag relative to recovery included decreased basal ganglia‐thalamocortical network connections and increased functional connectivity between the medial temporal lobe subsystem and medial visual cortex. The lower melatonin and higher thyroid hormone levels during jet lag showed the same trend as brain activity in the right lingual gyrus. Although there was no significant difference between cortisol measurements during and after jet lag, cortisol levels were associated with temporal lobe activity in the jet lag condition. Brain and neuroendocrine changes during jet lag were related to jet lag symptoms. Further prospective studies are needed to explore the time course over which jet lag acts on the human brain.     

Anaesthesia for endoscopic surgery

Anaesthesia for endoscopic airway surgery involves unique challenges. The anaesthetist and surgeon are working in close anatomical proximity and the concept of shared airway is never more relevant. Understanding the planned procedure and the needs of the surgeon for access to the surgical field will enable the provision of anaesthesia and airway management using a variety of techniques. Planning for safe induction, maintenance and emergence of anaesthesia will also be guided by the specific pathology and patient characteristics and requires effective communication between the surgeon and anaesthetist.     

Transtracheal jet ventilation

Transtracheal jet ventilation is a technique for ventilation of apnoeic lungs. This article outlines the indications, equipment required, insertion technique and complications of transtracheal jet ventilation. It can be used electively to aid management of the difficult airway and for laryngeal surgery. It also has a vital role in the management of the ‘can't intubate – can't ventilate’ scenario. Death and hypoxic brain damage under anaesthesia are fortunately rare, but most commonly occur as a result of problems with tracheal intubation. No patient should suffer hypoxic brain damage without an attempt at transtracheal ventilation being made.     

On the Production of Chitosan-Coated Polycaprolactone Nanoparticles in a Confined Impinging Jet Reactor

This work is focused on the synthesis of polycaprolactone nanoparticles, coated with chitosan, in a confined impinging jet reactor using the solvent displacement method. The role of the various reacting species was investigated, evidencing that a biocompatible polymer, for example, polycaprolactone, is required to support chitosan to obtain a monomodal particle size distribution, with low particle diameters. A surfactant is required to reduce the nanoparticle size (down to a mean diameter of about 260 nm) and obtain a positive zeta potential (about +31 mV), perfectly suitable for pharmaceutical applications. Different surfactants were tested, and Poloxamer 388 appeared to be preferable to polyvinyl alcohol. The effect of the concentration of Poloxamer 388 (in the range 0.5-5 mg mL^?1) and of chitosan (in the range 1.5-5 mg mL^?1) on both the mean particle size and zeta potential was also investigated, evidencing that chitosan concentration has the strongest effect on both parameters. Finally, the effect of solvent evaporation, quenching and feed flow rate was investigated, showing that the evaporation stage does not affect particle characteristics, quenching is required to avoid particle aggregation, and a minimum liquid flow rate of 80 mL min^?1 is required in the considered reactor to minimize the particle size.     

浙江省2015~2020年热带气旋对白纹伊蚊密度和登革热发病率的影响

目的 探索浙江省热带气旋与白纹伊蚊密度和人群登革热发病率的关联性。 方法 收集浙江省2015~2020年4~11月每日热带气旋数据、登革热发病数据和气象数据及每半月媒介伊蚊监测数据。利用广义相加模型分析热带气旋对白纹伊蚊密度和登革热发病的影响及滞后效应,其中热带气旋对登革热发病的影响进行年龄亚组分析。 结果 热带气旋可增加浙江省登革热发病风险,在滞后0、2 d时达到峰值,居民发病风险增加0.37倍(RR=1.37, 95%CI: 1.06~1.78;RR=1.37, 95%CI: 1.09~1.72)。不同年龄人群受到的影响不同,在滞后3、7 d时,45岁以上人群发病风险分别增加0.51倍(RR=1.51,95%CI:1.08~2.13)和0.58倍(RR=1.58,95%CI:1.16~2.16);在滞后5 d时,60岁以上人群发病风险达到最大(RR=1.64, 95%CI:1.12~2.40)。纳入布雷图指数的广义相加模型分析结果显示,热带气旋对登革热发病的影响在浙江省受到热带气旋影响的半月内最大,且45岁以下和60岁以上人群发病风险较高。在受到热带气旋影响的半月内布雷图指数更高,差异具有统计学意义。热带气旋不同累计影响天数的组间布雷图指数差异不具有统计学意义。 结论 热带气旋能增加人群登革热发病风险,60岁以上和45岁以下人群为高危人群,应采取有效措施加强对脆弱人群的保护,降低登革热发病风险。热带气旋期间蚊媒密度上升,应及时开展蚊媒消杀工作,降低区域内蚊媒密度。     

A Compressible Conserved Discrete Unified Gas-Kinetic Scheme with Unstructured Discrete Velocity Space for Multi-Scale Jet Flow Expanding into Vacuum Environment

The mechanism of jet flow expanding into vacuum environment (or extremely low density environment) is important for the propulsion unit of micro-electro-mechanical systems (MEMS), the thruster of spacecraft, the attitude control system of satellite, etc.. Since its flow field is often composed of local continuum region and local rarefied region, the jet flow into vacuum has noteworthy multi-scale transportation behaviors. Therefore, the numerical study of such flows needs the multi-scale schemes which are valid for both continuum and rarefied flows. In the past few years, a series of unified methods for whole flow regime (from continuum regime to rarefied regime) have been developed from the perspective of the direct modeling, and have been verified by sufficient test cases. In this paper, the compressible conserved discrete unified gas-kinetic scheme is further developed and is utilized for predicting the jet flows into vacuum environment. In order to cover the working conditions of both aerospace and MEMS applications, the jet flows with a wide range of inlet Knudsen (Kn) numbers (from 1E-4 to 100) are considered. The evolution of flow field during the entire startup and shutdown process with Kn number 100 is predicted by the present method, and it matches well with the result of analytical collisionless Boltzmann equation. For Kn numbers from 1E-4 to 10, the flow field properties such as density, momentum, and pressure are investigated, and the results are provided in details, since the published results are not sufficient at the present stage. The extent and intensity of the jet flow influence are especially investigated, because they are strongly related to the plume contamination and momentum impact on objects facing the jet, such as the solar paddles which face the attitude control thruster during the docking process.     

股二头肌长头肌皮瓣高压氧喷气式气垫综合治疗复杂性坐骨结节压疮

目的观察股二头肌长头肌皮瓣、高压氧及术后应用喷气式气垫综合治疗复杂性坐骨结节压疮的临床疗效。方法对16例坐骨结节压疮患者应用股二头肌长头肌皮瓣修复,联合高压氧治疗及术后长期应用喷气式气垫。结果 16例患者中14例一期愈合,1例肌皮瓣近臀侧边缘少量透明状液体渗出,经换药14 d愈合并拆线,1例肌皮瓣近臀侧皮肤拆线后裂开,经换药28 d后瘢痕愈合。所有患者坚持应用喷气式气垫床,2～7年随访无一例复发。结论股二头肌长头肌皮瓣修复坐骨结节压疮联合高压氧及术后坚持气垫床根治复杂性坐骨结节压疮疗效确切。     

IL6Rα function in myeloid cells modulates the inflammatory response during irritant contact dermatitis

Irritant contact dermatitis (ICD) is characterized by epidermal hyperplasia, infiltration of leucocytes into lesional skin and inflammatory cytokine release. The cellular infiltrate during ICD comprises primarily cells of the myeloid lineage. Our group has previously shown that the cytokine IL‐6 confers a protective effect to lesional skin during ICD. How IL‐6Rα function in myeloid cells is involved in the inflammatory response during ICD is, however, unknown. In the present study, utilizing a chemical model of ICD, it is shown that mice with a myeloid‐specific knockout of the IL‐6Rα (IL‐6Rα^Δmyeloid) display an exaggerated inflammatory response to benzalkonium chloride (BKC) and Jet propellant‐8 (JP8) fuel, two well‐characterized irritants relative to littermate control. Results from immunohistochemical and flow cytometric analyses revealed that IL‐6Rα^Δmyeloid mouse skin displayed increased epidermal hyperplasia and inflammatory monocyte influx into lesional skin but lower numbers of resident macrophages relative to littermate controls after irritant exposure. Multiplex immunoassay revealed significantly higher levels of pro‐inflammatory cytokines IL‐1α and TNF‐α, but reduced expression of chemokine proteins including CCL2‐5, CCL7, CCL11, CXCL1 and CXCL10 in IL‐6Rα^Δmyeloid mouse skin relative to littermate control following irritant exposure. These results highlight a previously unknown role of IL‐6Rα function in myeloid cells in modulating the inflammatory response and myeloid population dynamics during ICD.     

Effects of Aerosol-Vapor JP-8 Jet Fuel on the Functional Observational Battery,and Learning and Memory in the Rat

To determine whether JP-8 jet fuel affects parameters of the Functional Observational Battery (FOB), visual discrimination, or spatial learning and memory, the authors exposed groups of male Fischer Brown Norway hybrid rats for 28 d to aerosol/vapor-delivered JP-8, or to JP-8 followed by 15 min of aerosolized substance P analogue, or to sham-confined fresh room air. Behavioral testing was accomplished with the U.S. Environmental Protection Agency's Functional Observational Battery. The authors used the Morris swim task to test visual and spatial learning and memory testing. The spatial test included examination of memory for the original target location following 15 d of JP-8 exposure, as well as a 3-d new target location learning paradigm implemented the day that followed the final day of exposure. Only JP-8 exposed animals had significant weight loss by the 2nd week of exposure compared with JP-8 with substance P and control rats; this finding compares with those of prior studies of JP-8 jet fuel. Rats exposed to JP-8 with or without substance P exhibited significantly greater rearing and less grooming behavior over time than did controls during Functional Observational Battery open-field testing. Exposed rats also swam significantly faster than controls during the new target location training and testing, thus supporting the increased activity noted during Functional Observational Battery testing. There were no significant differences between the exposed and control groups' performances during acquisition, retention, or learning of the new platform location in either the visual discrimination or spatial version of the Morris swim task. The data suggest that although visual discrimination and spatial learning and memory were not disrupted by JP-8 exposure, arousal indices and activity measures were distinctly different in these animals.