Effects of ambient pressure on smoke propagation in inclined tunnel fires under natural ventilation.

This paper systematically studied the coupling effect of ambient pressure and tunnel slope on temperature distribution and smoke propagation in full-scale tunnel fires under natural ventilation by FDS. The downstream length (longitudinal length from fire source center to tunnel downstream exit) was also considered. The concept of "height difference of stack effect" was put forward when analyzing the mutual effect of tunnel slope and downstream length on smoke movement. The results show that the maximum smoke temperature beneath the ceiling decreases with the increasing ambient pressure or tunnel slope. The longitudinal smoke temperature decays faster with the decreasing ambient pressure or slope in inclined tunnel. The induced inlet airflow velocity increases with the increasing height difference of stack effect, while decreases with the increasing ambient pressure. And the smoke backlayering length decreases with the increasing height difference of stack effect. Taking heat release rate (HRR), ambient pressure, tunnel slope and downstream length into account, the prediction models of dimensionless induced inlet airflow velocity and smoke backlayering length in inclined tunnel fires at high altitude were developed, which agree well with our and others' results. The outcomes of current study are great meaningful to fire detection and smoke control in inclined tunnel fires at high altitude.

Study on Lactiplantibacillus plantarum R6-3 from Sayram Ketteki to prevent chronic unpredictable mild stress-induced depression in mice through the microbiota-gut-brain axis.

The prevention, mitigation and treatment of depression has become a global issue that needs to be solved urgently. Sayram Ketteki, a traditional natural fermented yoghurt from the region with the world's fourth highest life expectancy, has been known as the "longevity secret", whose longevity and anti-depression factors are speculated to come from its rich microorganisms. Therefore, for the first time, we systematically studied in depth the microbes of Sayram Ketteki, screened a new edible probiotic strain, Lactiplantibacillus plantarum R6-3, and explored its anti-depression effect in chronic unpredictable mild stress (CUMS)-induced depression in mice. It is encouraging that L. plantarum R6-3 was significantly superior to the classic anti-depressant drug, fluoxetine, in the performance of promoting sucrose preference test (SPT) behavior by 18% (p < 0.001), lowering the serum CORT content by 5.6% (p < 0.05), accelerating the brain-derived neurotrophic factor (BDNF) level by 5.9% (p < 0.01), increasing the serum IL-10 concentration by 2.3% (p < 0.05), up-regulating the expression of BDNF and phosphorylated-ERK by 74% (p < 0.01) and 45% (p < 0.001), respectively, and facilitating the secretion of fecal short-chain fatty acids (SCFAs), including n-butyric, n-valeric, and isovaleric acid by 47% (p < 0.01), 42% (p < 0.05) and 38% (p < 0.05), respectively. Through the microbiota-gut-brain axis, L. plantarum R6-3 promoted the secretion of intestinal SCFAs through regulation of the composition and function of the gut microbiota, and activated the production of the monoamine neurotransmitter, renewed the level of brain neurotrophic factor, and suppressed the hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis by adjusting the hippocampal BDNF/TrkB/ERK/CREB signaling pathway, thereby improving the immune and oxidative stress status, protecting hippocampal tissue from damage, maintaining a healthy weight and preventing CUMS-induced depressive behavior in mice. It has great prospects for the development of natural functional foods, the prevention and treatment of depression and in innovative microecological preparations.

Antifriction and Antiwear Effect of Lamellar ZrS2 Nanobelts as Lubricant Additives.

In this study, the tribological behavior of lamellar ZrS2 nanobelts as lubricant additives was investigated under different concentrations, normal load, velocity, and temperature. The friction and wear tests were performed using a tribometer and with a reciprocating motion. The results indicate that the lamellar ZrS2 nanobelt additives can effectively reduce the coefficient of friction and running-in time during the running-in period. With the addition of ZrS2, the wear volumes decrease significantly. The wear is mostly influenced by the tribological performance throughout the running-in period. The lower the running-in time and coefficient of friction are during the running-in period, the less amount of wear is shown. ZrS2 can significantly increase the load-carrying capacity of oil. The 1.0 wt% concentration of ZrS2 yields the best antifriction effect, antiwear performance, and load-carrying capacity. The ZrS2 additives can increase the working temperature of the oil. The friction-reducing and antiwear mechanisms of lamellar ZrS2 were discussed.

Tribological Behavior of Lamellar Molybdenum Trioxide as a Lubricant Additive.

In this study, the tribological behavior of lamellar MoO3 as a lubricant additive was investigated under different concentrations, particle sizes, normal loads, velocity, and temperature. The friction and wear tests were performed using a tribometer and with a reciprocating motion. The results indicate that the friction-reducing ability and antiwear property of the base oil can be improved effectively with the addition of lamellar MoO3. The 0.5 wt % and 0.1 wt % concentrations of MoO3 yield the best antifriction and antiwear effects, respectively. The maximum friction and wear reduction is 19.8% and 55.9%, compared with that of the base oil. It is also found the MoO3 additive can decrease the friction considerably under a high velocity and normal load, and increase the working temperature. The smaller the size of MoO3, the better the friction-reducing effect the lamellar MoO3 shows. The friction-reducing and antiwear mechanisms of lamellar MoO3 were discussed.

Hippocampal ß2­microglobulin mediates sepsis­induced cognitive impairment.

Acute brain dysfunction is a frequent complication in sepsis patients and is associated with long­term neurocognitive consequences and increased mortality, yet the underlying mechanism remains unclear. Emerging evidence has suggested that ß2­microglobulin [a component of major histocompatibility complex (MHC) class I molecules] is involved in cognitive dysfunction in various neurological diseases. Therefore, the present study tested the hypothesis that ß2­microglobulin in the brain also mediates sepsis­induced cognitive impairment. In the present study, wild­type and antigen processing 1 (Tap1)­deficient mice (Tap1­/­) were subjected to cecal ligation and puncture (CLP). Survival rate, cognitive function, and biochemical analysis were performed at the indicated time points. The data revealed that CLP induced anxiety­like behavior and impaired hippocampal­dependent contextual memory in wild­type mice, which was accompanied by hippocampal microglial activation, increased level of interleukin­1ß, and decreased concentrations of brain derived neurotrophic factor and postsynaptic density protein 95. Notably, it was demonstrated that Tap1­/­ mice with reduced cell surface expression of MHC I protected mice from anxiety­like behavior and impaired hippocampal­dependent contextual memory and reversed most of these biochemical parameters following sepsis development. In summary, the results of the present study suggest that ß2­microglobulin negatively regulates cognitive impairment in an animal model of sepsis induced by CLP.

Application of water@silica core-shell particles for suppressing gasoline pool fires.

A new type of dry powders with capsular structure was fabricated for fire suppression, in which the content of water approached 60%. The capsules with the size of 3-5µm consisted of liquid core and solid shell, where the core was water droplet and the shell was assembled silicon dioxide particles with surface hydrophobic modification. The shell of close-packed silica particles surrounding each water droplet provided the structural rigidity of the capsules and enabled their application as powder fire suppressants. Two different scaled real fire tests showed that thus-prepared solid powders could extinguish 0.21MW gasoline pool fire in 2.0s with agent mass of 0.055kg, and 1.0MW gasoline pool fire in 5.0s with agent mass of 0.49kg. Such fire extinguishing performance greatly outperformed the conventional monoammonium phosphate (ABC) powders, neat silica powders and water mist, with significantly reduced fire extinguishing time and mass of agent consumed. Mechanism of the core-shell particles in fire suppression was discussed based on established theories and experimental results.

Neuroinflammation-Induced Downregulation of Hippocampacal Neuregulin 1-ErbB4 Signaling in the Parvalbumin Interneurons Might Contribute to Cognitive Impairment in a Mouse Model of Sepsis-Associated Encephalopathy.

Sepsis-associated encephalopathy (SAE) is a common complication associated with poor prognosis in septic patients, but the underlying mechanism remains unclear. We hypothesized that disturbed neuregulin 1 (NRG1)-ErbB4 signaling in the parvalbumin interneurons was involved in sepsis-induced cognitive impairment in a mouse model of SAE. The SAE model was induced by cecal ligation/perforation (CLP). Animals were randomly divided into the following six groups: sham + vehicle group, sham + NRG1 group, CLP + vehicle group, CLP + NRG1 group, CLP + NRG1 + AG1478 (ErbB4 inhibitor) group, and CLP + minocycline group. Behavioral tests and in vivo electrophysiology were performed at the indicated time points. The brain tissues were harvested to determine the levels of hippocampcal cytokines, IBA1-positive cells, NRG1, ErbB4, and parvalbumin. In the present study, sepsis induced the anxiety-like behavior and hippocampal-dependent cognitive impairment, as reflected by significantly increased distance spent in the open field test and decreased freezing time to context in the fear conditioning test. The abnormal behavioral changes co-occurred with significant increases in hippocampal IBA1-positive cells, IL-1ß and IL-6 levels, and decreased NRG1, ErbB4, parvalbumin expressions, and evoked gamma activity. NRG1 treatment attenuated the sepsis-induced cognitive impairment and the associated biochemical markers, which were abolished by AG1478 administration. Notably, minocycline treatment attenuated neuroinflammation and mimicked the beneficial effects of NRG1 treatment. In summary, we provided additional evidence that the disruption of NRG1-ErbB4 signaling in the parvalbumin interneurons mediated by neuroinflammation might lead to abnormal gamma oscillations and thus contribute to cognitive impairment in a mouse model of SAE.

Polycystic ovary syndrome (PCOS) and the risk of coronary heart disease (CHD): a meta-analysis.

Some studies reported a significant association between polycystic ovary syndrome (PCOS) and risk of cardiovascular disease (CVD). However, the results are controversial. A systematic search was conducted in the PubMed, Science Direct, EMBASE, and Cochrane Library databases. Five case-control studies and 5 cohort studies were selected, involving a total of 104392 subjects in this meta-analysis. PCOS was significantly associated with the increased risk of CVD (OR = 1.30; 95% CI 1.09 - 1.56; P = 0.004). In the subgroup analysis of study design, both case-control studies and prospective cohort studies showed significant results (OR = 1.79; 95% CI 1.16 - 2.77; P = 0.009; OR = 1.20; 95% CI 1.06 - 1.37; P = 0.005), while retrospective cohort studies did not show positive result (OR = 0.91; 95% CI 0.60 - 1.40; P = 0.68). In a further stratified analysis by type of CVD, a significant association was found between PCOS and coronary heart disease (CHD) (OR = 1.44; 95% CI 1.13 - 1.84; P = 0.004). However, no significant association was observed between PCOS and myocardial infarction (MI) (OR = 1.01; 95% CI 0.68 - 1.51; P = 0.95). In conclusion, this meta-analysis suggested that PCOS is significantly associated with increased CHD risk.

Disrupted Tryptophan Metabolism Induced Cognitive Impairment in a Mouse Model of Sepsis-associated Encephalopathy.

Sepsis-associated encephalopathy (SAE) is a common complication in critically ill patients and is associated with a poor prognosis. However, the precise mechanisms underlying sepsis-induced cognitive impairment remain largely to be elucidated. The aim of the present study was to investigate whether indoleamine 2, 3-dioxygenase (IDO) activation-mediated neurotoxicity is involved in the pathophysiology of sepsis-induced cognitive impairment. Sepsis was induced by cecal ligation/perforation (CLP). The animals were randomly divided into the following five groups: Sham + vehicle group; Sham + 1-methyl-D, L-tryptophan group; Sham + L-Kynurenine group; CLP + vehicle group; or CLP + 1-methyl-D, L-tryptophan group. The survival rate was estimated by the Kaplan-Meier method. Behavioral tests were performed by the open field and fear conditioning tests at days 13 and 14 after operation. In the present study, we demonstrated that sepsis induced a deficit in hippocampus-dependent cognitive impairment in a mouse model of SAE. Furthermore, a single peripheral kynurenine administration, the metabolic product of IDO, induced a deficit in the cognitive impairment in the sham mice. However, mice treated with IDO inhibitor 1-methyl-D, L-tryptophan were protected from sepsis-induced cognitive impairment. In conclusion, our study implicates IDO-dependent neurotoxic kynurenine metabolism as a critical factor responsible for the sepsis-induced cognitive impairment and a potential novel target for the treatment of SAE.

Characteristics of participants' and caregivers' influence on non-response in a cross-sectional study of dementia in an older population.

OBJECTIVE: The issue of non-response in dementia epidemiological studies, which may result in the underestimation of the prevalence of dementia, has attracted little attention. We aimed to explore the causes and related factors of non-response in a dementia survey among Chinese veterans. METHODS: A two-phase, cross-sectional study investigated the prevalence of dementia and mild cognitive impairment in Chinese veterans aged ≥ 60 years. We collected the socio-demographic data and prior medical history, evaluated the health status of veterans and their caregivers, assessed the cognitive status of veterans, and evaluated the care burden of caregivers by Caregiver Burden Inventory (CBI). RESULTS: Of 9676 eligible participants, 525 (5.4%) veterans in phase 1 and 1706 (35.0%) veterans among 4875 veterans in phase 2 did not respond. Illness, hospitalization and death accounted for 63.0% and 75.5% non-response in phases 1 and 2, respectively. Non-participation in social activities, self-perceived poor health status, worsened health changes, self-reported need for life care, and history of hearing loss or glaucoma independently predicted non-response in phase 1 or 2. The heavy care burden, suggested by the higher CBI scores and self-reported health deterioration of the primary caregivers, predicted non-response in phase 1 or 2. CONCLUSIONS: The negative factors from both the participants and their caregivers independently predicted the non-response in the dementia study in an older population. Preventative strategies from the perspectives of the participants and caregivers should be developed to improve the response rates in both phases in a cross-sectional study.

Construction of the Chinese Veteran Clinical Research (CVCR) platform for the assessment of non-communicable diseases.

BACKGROUND: Based on the excellent medical care and management system for Chinese veterans, as well as the detailed medical documentation available, we aim to construct a Chinese Veteran Clinical Research (CVCR) platform on non-communicable diseases (NCDs) and carry out studies of the primary disabling NCDs. METHODS: The Geriatric Neurology Department of Chinese People's Liberation Army General Hospital and veterans' hospitals serve as the leading and participating units in the platform construction. The fundamental constituents of the platform are veteran communities. Stratified typical cluster sampling is adopted to recruit veteran communities. A cross-sectional study of mental, neurological, and substance use (MNS) disorders are performed in two stages using screening scale such as the Mini-Mental State Examination and Montreal cognitive assessment, followed by systematic neuropsychological assessments to make clinical diagnoses, evaluated disease awareness and care situation. RESULTS: A total of 9 676 among 277 veteran communities from 18 cities are recruited into this platform, yielding a response rate of 83.86%. 8 812 subjects complete the MNS subproject screening and total response rate is 91.70%. The average participant age is (82.01±4.61) years, 69.47% of veterans are 80 years or older. Most participants are male (94.01%), 83.36% of subjects have at least a junior high school degree. The overall health status of veterans is good and stable. The most common NCD are cardiovascular disorders (86.44%), urinary and genital diseases (73.14%), eye and ear problems (66.25%), endocrine (56.56%) and neuro-psychiatric disturbances (50.78%). CONCLUSION: We first construct a veterans' comprehensive clinical research platform for the study of NCDs that is primarily composed of highly educated Chinese males of advanced age and utilize this platform to complete a cross-sectional national investigation of MNS disorders among veterans. The good and stable health condition of the veterans could facilitate the long-term follow-up studies of NCDs and provide prospective data to the prevention and management of NCDs.