Variations of the urban PM2.5 chemical components and corresponding light extinction for three heating seasons in the Guanzhong Plain, China.

In order to investigate the variations of PM2.5 (particulate matter with an aerodynamic diameter less than 2.5 µm) chemical components responding to the pollution control strategy and their effect on light extinction (bext) in the Guanzhong Plain (GZP), the comparisons of urban atmospheric chemical components during the heating seasons were extensively conducted for three years. The average concentration of PM2.5 decreased significantly from 117.9 ± 57.3 µg m-3 in the heating season 1 (HS1) to 53.5 ± 31.3 µg m-3 in the heating season 3 (HS3), which implied that the effective strategies were implemented in recent years. The greatest contribution to PM2.5 (∼30%) was from Organic matter (OM). The heightened contributions of the secondary inorganic ions (SNA, including NO3-, SO42-, and NH4+) to PM2.5 were observed with the values of 34% (HS1), 41% (HS2), and 42% (HS3), respectively. The increased percentages of NO3- contributions indicated that the emission of NOx should be received special attention in the GZP. The comparison of PM2.5 chemical compositions and implications across major regions of China and the globe were investigated. NH4NO3 was the most important contributor to bext in three heating seasons. The average bext was decreased from 694.3 ± 399.1 Mm-1 (HS1) to 359.3 ± 202.3 Mm-1 (HS3). PM2.5 had a threshold concentration of 75 µg m-3, 64 µg m-3, and 57 µg m-3 corresponding to the visual range (VR) < 10 km in HS1, HS2, and HS3, respectively. The enhanced impacts of the oxidant on PM2.5 and O3 were observed based on the long-term variations in PM2.5 and OX (Oxidant, the sum of O3 and NO2 mixing ratios) over the five heating seasons and PM2.5 and O3 over six summers from 2016 to 2021. The importance of coordinated control of PM2.5 and O3 was also investigated in the GZP.

Highly Efficient Oxygen Reduction N-Doped Carbon Nanosheets Were Prepared by Hydrothermal Carbonization.

A metal-free carbon catalyst is a kind of oxygen reduction catalyst with great prospects. It is an important material with potential to replace the traditional Pt catalyst. In this paper, a kind of irregular and ultra-thin carbon nanosheet (K180M-300-900) with high catalytic activity was synthesized by hydrothermal calcination using okra as a biomass and NH4Cl as an N source. The prepared nitrogen-doped metal-free catalyst with high pyridine-N and graphitic-N provides an extremely large number of active sites and has certain lattice defects. Ultra-thin carbon nanosheets promote sufficient contact between the catalyst and electrolyte, promote the diffusion of oxygen, and result in a faster transfer rate of electrons. The initial potential and half-slope potential of K180M-300-900 are 0.99 V and 0.82 V, respectively, which are comparable to those of 20% Pt/C. In addition, the stability and methanol tolerance of this catalyst (K180M-300-900) are better than 20% Pt/C, so it has great development potential and application value. This result provides a new method to prepare metal-free carbon materials that will take the place of traditional Pt catalysts.

Tribological Properties of Laser Microtextured Surface Bonded With Composite Solid Lubricant at High Temperature.

A combination technology of the solid lubricant and the laser surface texturing (LST) can significantly improve the tribological properties of friction pairs. The plate sample was textured by fiber laser and composite lubricant of polyimide (PI) and molybdenum disulfide (MoS2) powders were filled in the microdimples. Sliding friction performances of micron-sized composite lubricant and nano-sized composite lubricant were investigated by ring-plate tribometer at temperatures ranging from room temperature (RT) to 400 °C. On the one hand, the results of the micron-sized composite lubricant show that the friction coefficient of the textured surface filled with composite lubricant (TS) exhibits the lowest level and the highest stability compared to a textured surface without solid lubrication, smooth surface without lubrication, smooth surface burnished with a layer of composite solid lubricant. The better dimple density range is 35-46%. The friction coefficients of the sample surface filled with micron-composite solid lubricant with the texture density of 35% are maintained at a low level (about 0.1) at temperatures ranging from RT to 300 °C. On the other hand, the results of the nano-sized composite lubricant show that these friction properties are better than those of MoS2-PI micron-sized composite. The friction coefficients of MoS2-PI-CNTs nano-sized composite solid lubricant are lower than those of the MoS2-PI composite lubricant at temperatures ranging from RT to 400 °C. In addition, the possible mechanisms involving the synergetic effect of the surface texture and the solid lubricant are discussed in the present work.

Study on the mechanism of gut microbiota in the pathogenetic interaction between depression and Parkinson 's disease.

Depression and Parkinson's disease share pathogenetic characteristics, meaning that they can impact each other and exacerbate their respective progression. From a pathogenetic perspective, depression can develop into Parkinson's disease and is a precursor symptom of Parkinson's disease; Parkinson's disease is also often accompanied by depression. From a pharmacological perspective, the use of antidepressants increases the risk of developing Parkinson's disease, and therapeutic medications for Parkinson's disease can exacerbate symptoms of depression. Therefore, identifying how Parkinson's disease and depression impact each other in their development is key to formulating preventive measures and targeted treatment. One commonality in the pathogenesis of depression and Parkinson's disease are alterations in the gut microbiota, with mechanisms interacting in neural, immune inflammatory, and neuroendocrine pathways. This paper reviews the role of gut microbiota in the pathogenesis of depression and Parkinson's disease; conducts a study of the relationship between both conditions and medication; and suggests that dysregulated gut microbiota may be a key factor in explaining the relationship between Parkinson's disease and depression. Finally, on the basis of these findings, this article hopes to provide suggestions that new ideas for the prevention and treatment of depression and Parkinson's disease.

School Bullying, Bystander Behavior, and Mental Health among Adolescents: The Mediating Roles of Self-Efficacy and Coping Styles.

While numerous studies have revealed the impact of different bullying behaviors, such as victimization and perpetration, on the psychological development of adolescents, the exploration of the correlates of positive/negative bystander behaviors and their potential underlying mechanisms remains scarce in China. The present study aims to compare the relationships between mental health and positive versus negative bystander behavior and to clarify whether self-efficacy and coping styles mediate the relationships between mental health and bullying dynamics. The current study was conducted on 11,734 students from 18 secondary schools in Suzhou, China (Meanage = 15.00, SDage = 1.47; 53.8% boys). The information on bullying victimization, perpetration, positive/negative bystander behaviors, as well as self-efficacy, coping styles and mental health variables (including depression, anxiety, sleep disturbance, suicide risk), were collected. Negative bystander behavior was positively associated with mental health problems, while positive bystander behavior was negatively associated with these factors. Also, further analysis showed that coping styles and self-efficacy mediated the relationship between different bullying behaviors and mental health outcomes. The results highlighted the comparison of the correlates of positive and negative bystander behaviors, which were comparably crucial to those of victims and perpetrators for prevention and intervention efforts. Promoting adaptive coping styles and self-efficacy to buffer the deleterious psychological consequences of bullying behavior in adolescents was also important.

Prevalence and clinical correlates of benzodiazepine use in the patients with major depressive disorder.

BACKGROUND: Major depressive disorder (MDD) is a serious and disabling condition characterized by abnormal mood changes. Clinical guidelines for depression treatment recommend antidepressant medications, with benzodiazepines acting as short-term synergists. However, little is currently known about the prevalence and associated clinical risk factors of benzodiazepine use among Chinese patients with MDD. This study aimed to explore the prevalence and clinical risk factors associated with benzodiazepine use in this population. METHODS: A total of 2742 patients with MDD (males/females = 816/1926, aged 14-60 years) participated in this cross-sectional observational study. General information and psychosis assessments were collected online. Depressive symptoms were assessed using the Patient Health Questionnaire-9 (PHQ-9), anxiety symptoms using the Generalized Anxiety Disorder-7 (GAD-7), and sleep problems and suicidal tendencies using the third and ninth items of the PHQ-9. Multivariable logistic regression analysis models were employed to identify factors associated with benzodiazepine use. RESULTS: The prevalence of benzodiazepine use among patients with MDD was 42.9 %. Among these patients, 99.6 % used a single benzodiazepine, with oxazepam being the most frequently prescribed. Age, severity of sleep problems, depressive symptoms, and anxiety symptoms were significantly correlated with benzodiazepine use (all P < 0.001). LIMITATIONS: The cross-sectional design of this study precludes establishing causal relationships. CONCLUSION: Our findings indicate a high prevalence of benzodiazepine use among Chinese patients with MDD. Factors such as severe depressive symptoms, anxiety symptoms, age, and sleep problems appear to be associated with benzodiazepine use. These results underscore the importance of vigilance regarding benzodiazepine use in patients with MDD.

Clinical Application of Proximal Arch Cannulation in the Surgical Treatment of Acute Type I Aortic Dissection.

Objective The goal is to determine the best location for inserting a catheter into the aortic arch of patients with a certain type of aortic dissection (DeBakey type I) by analyzing images of the patient's aortic arch before surgery. This analysis will take into account the shape and structure of the patient's aortic arch to find the most optimal location for cannulation. Methods A retrospective analysis was conducted on 100 patients with acute DeBakey type I aortic dissection diagnosed between January 2021 and February 2023, utilizing the Carestream medical imaging software Image Suite V4 (New York, USA). The study included 67 cases that underwent surgery and 33 cases that did not. The study aimed to evaluate the optimal intubation position on the patient's aortic arch by analyzing the true and false lumen classification, true and false lumen area, and hematoma thickness on the patient's aortic arch, as observed in the aortic computed tomography angiography (CTA) conducted upon admission. Results The vascular axis analysis showed a significant difference in the true lumen area among the three regions that were examined (P < 0.001). Zone 1 had a larger true lumen area of 6.40 ± 2.71 cm2 compared to zone 2 with 5.75 ± 2.13 cm2 and zone 3 with 4.85 ± 1.70 cm2, as determined by statistical analysis. In addition, the statistical analysis of hematoma thickness in the three regions where cannulation can be performed revealed a significant difference among the three groups (P = 0.027). Further analysis showed that there was no significant difference between zone 1 and zone 2 (P = 1.000), a significant difference between zone 1 and zone 3 (P < 0.046), and no significant difference between zone 2 and zone 3 (P = 0.080). The difference between zone 1 false lumen thickness of 1.55 ± 0.51 cm and zone 3 false lumen thickness of 1.33 ± 0.55 cm was found to be small. Conclusion Cannulation of the aortic arch is a common strategy used in cardiac surgery. Accurate cannulation is critical to the success of the procedure. The use of CTA provides valuable guidance for the cannulation procedure. A thorough examination of CTA and precise measurement of relevant parameters can help guide the surgeon to determine the optimal cannulation site. The study found that zone 1 of the aortic arch has the largest area and is the most suitable for cannulation, in accordance with the physiological characteristics and surgical practices of a surgeon. Furthermore, cannulation of the aortic arch has been found to be a safe and effective strategy for cannulation. Overall, careful examination of CTA and accurate measurement of relevant parameters can have a significant guiding effect on the cannulation of the aortic arch, which can lead to improved outcomes in cardiac surgery.

Bilateral repetitive transcranial magnetic stimulation ameliorated sleep disorder and hypothalamic-pituitary-adrenal axis dysfunction in subjects with major depression.

Objective: In this study, we sought to explore the effectiveness of bilateral repetitive transcranial magnetic stimulation (rTMS) over the dorsolateral prefrontal cortex (DLPFC) on depressive symptoms and dysfunction of hypothalamic-pituitary-adrenal (HPA) axis in patients with major depressive disorder (MDD). Materials and methods: One hundred and thirty-six adults with MDD were administrated drugs combined with 3 weeks of active rTMS (n = 68) or sham (n = 68) treatment. The 17-item Hamilton Depression Rating Scale for Depression (HAMD-17) was to elevate depression severity at baseline and weeks 4. To test the influence of rTMS on the HPA axis, plasma adrenocorticotropic hormone (ACTH) and serum cortisol (COR) were detected in pre- and post-treatment. Results: No statistical significance was found for the baseline of sociodemographic, characteristics of depression, and psychopharmaceutical dosages between sham and rTMS groups (p > 0.05). There was a significant difference in the HAMD-17 total score between the two groups at end of 4 weeks after treatment (p < 0.05). Compared to the sham group, the rTMS group demonstrated a more significant score reduction of HAMD-17 and sleep disorder factor (HAMD-SLD) including sleep onset latency, middle awakening, and early awakening items at end of 4-week after treatment (p < 0.05). Furthermore, total score reduction of HAMD-17 was correlated with a decrease in plasma ACTH, not in COR, by rTMS stimulation (p < 0.05). Conclusion: Bilateral rTMS for 3 weeks palliated depression via improvement of sleep disorder, and plasma ACTH is a predictor for the efficacy of rTMS, especially in male patients with MDD.

High-frequency repetitive transcranial magnetic stimulation alleviates the cognitive side effects of electroconvulsive therapy in major depression.

Objective: The retrospective study aimed to explore the difference in mood outcomes and cognitive function between high-frequency repetitive transcranial magnetic stimulation (HF-rTMS) over dorsolateral prefrontal cortex (DLPFC) and electroconvulsive therapy in major depression disorder (MDD) patients and to examine the improvement of HF-rTMS on cognitive impairment evoked by electroconvulsive therapy (ECT). Materials and methods: A total of 116 participants with MDD, who completed a 4-week follow-up assessment, were enrolled. The cohort consisted of 26 cases classed as control, 46 participants administrated with HF-rTMS (HF-rTMS group), 22 patients treated with ECT (ECT group), and 23 cases treated with HF-rTMS and ECT at the course of hospitalization (HF-rTMS + ECT group). Medication was kept constant as well in all participants. The 17-item Hamilton Depression Rating Scale for Depression (HAMD-17) and 14-item Hamilton Anxiety Rating Scale (HAMA-14) were used to assess depression and anxiety, respectively. Montreal Cognitive Assessment (MoCA) was to elevate cognitive function. Results: No statistical significance was found for baseline in sociodemographic, characteristics of depression, anxiety and cognition, and psychopharmaceutic dosages among control, HF-rTMS, ECT, and HF-rTMS + ECT groups (p > 0.05). Compared with baseline level, total scores of HAMD-17 and HAMA-14 significantly decreased at the end of 4 weeks after treatment (p < 0.001). Furthermore, the decline in scores of HAMD-17 and its sleep disorder and retardation factors from baseline to post-treatment was greater in HF-rTMS, ECT, and HF-rTMS + ECT group than in control (p < 0.05), and there was a significant difference between control and HF-rTMS group in the decline of psychological factor of HAMA-14 (p < 0.01). ECT treatment evoked total score of MoCA to decrease significantly at the end of 4-week after intervention (p < 0.001), and the decline in scores of MoCA and its delayed recall and language performances from baseline to post-treatment was greater in ECT than control, HF-rTMS, and HF-rTMS + ECT (p < 0.05). Conclusion: High-frequency repetitive transcranial magnetic stimulation improved psychological anxiety and ameliorated the cognition impairment evoked by ECT though it had the same anti-depressant efficacy as ECT.

Biocompatibility evaluation of silk fibroin with peripheral nerve tissues and cells in vitro.

Silk-based materials have been used in the field of bone or ligament tissue engineering. In order to explore the feasibility of using purified silk fibroin to construct artificial nerve grafts, it is necessary to evaluate the biocompatibility of silk fibroin material with peripheral nerve tissues and cells. We cultured rat dorsal root ganglia (DRG) on the substrate made up of silk fibroin fibers and observed the cell outgrowth from DRG during culture by using light and electron microscopy coupled with immunocytochemistry. On the other hand, we cultured Schwann cells from rat sciatic nerves in the silk fibroin extract fluid and examined the changes of Schwann cells after different times of culture. The results of light microscopy, MTT test and cell cycle analysis showed that Schwann cells cultured in the silk fibroin extract fluid showed no significant difference in their morphology, cell viability and proliferation as compared to that in plain L15 medium. Furthermore, no significant difference was found in expression of the factors secreted by Schwann cells, such as nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and S-100, between Schwann cells cultured in the silk fibroin extraction fluid and in plain L15 medium by the aid of immunocytochemistry, RT-PCR and Western analysis. Collectively, these data indicate that silk fibroin has good biocompatibility with DRG and is also beneficial to the survival of Schwann cells without exerting any significant cytotoxic effects on their phenotype or functions, thus providing an experimental foundation for the development of silk fibroin as a candidate material for nerve tissue engineering applications.

Evaluation of precipitation from CMORPH, GPCP-2, TRMM 3B43, GPCC, and ITPCAS with ground-based measurements in the Qinling-Daba Mountains, China.

The correspondence between five precipitation products, including CMORPH, GPCP-2, TRMM 3B43, GPCC, and ITPCAS, and ground-based measurements of precipitation were evaluated on annual, seasonal, and monthly scales during 2000-2014 in the Qinling-Daba Mountains over China, which is a significant area with vital value of climate and hydrology. Performances of the precipitation products in the relatively arid/humid years were also analyzed. In general, ITPCAS data displayed the highest accuracy, GPCP-2 and CMORPH data showed relatively poor performance, and GPCC and TRMM 3B43 data were average at different temporal scales among the five precipitation products. The Pearson correlation coefficient of each station had minor fluctuations for the five precipitation products. A larger deviation was found at Wudu station, most likely due to the undulating terrain. The performances of the precipitation products from highest to least accuracy are as follows: ITPCAS > TRMM 3B43 > GPCC > GPCP-2 > CMORPH. Except for CMORPH (-20.76%), the percentage precipitation differences (PPDs) of the other four precipitation products fluctuated in the range of 10% during the relatively arid (2001) and humid (2011) years. In addition, all precipitation products and ground gauge observed precipitation did not show an obvious gradient with altitude, which is different from that in other mountainous areas and is perhaps due to complex terrain, lack of observation in high altitudes, and precipitation undercatch. In consideration of the significance of Qinling-Daba Mountains as the geographic and ecological dividing lines, the present study may provide a new perspective for hydrological, climatic, and ecological researches and practices in local and other mountainous areas.

The interaction of Schwann cells with chitosan membranes and fibers in vitro.

The bridging of nerve gaps is still one of the major problems in peripheral nerve regeneration. A promising alternative for the repair of peripheral nerve injuries is the bioartificial nerve graft, comprised of a biomaterial pre-seeded with Schwann cells (SCs), which is an effective substrate for enhancing nerve regeneration. Interaction between cultured SCs and biomaterials is of importance. For the purposes of this study, culture systems of normal SCs were used. The biocompatibility of chitosan, including chitosan membranes and chitosan fibers, was evaluated in vitro. The growth of SCs was observed by light and scanning electron microscopy at regular intervals. SCs were identified by immunocytochemical staining and the viability of SCs was measured by MTT assay. The experimental results indicated that SCs could grow onto chitosan materials with two different shapes: spherical and long olivary. They contacted with the extensions. The long olivary cells inclined to encircle chitosan fibers up. It was also found that the cells on the chitosan fibers migrated faster than those on the chitosan membranes. There was a good biological compatibility between chitosan and SCs. Compared with the chitosan membranes, SCs migrated more easily onto the stereoframe of chitosan fibers. These studies contribute information necessary to enhancing our understanding of biocompatibility of chitosan.

Evaluation of biocompatibility of polypyrrole in vitro and in vivo.

In this study, the biocompatibility of the electrically conductive polymer polypyrrole (PPy) with nerve tissue was evaluated in vitro and in vivo. The extraction solution of PPy powder, which was synthesized chemically, was tested for acute toxicity, subacute toxicity, pyretogen, quantitative measure of cell viability, hemolysis, allergen, and micronuclei. The PPy membrane was synthesized electrochemically on the indium tin oxide conductive borosilicate glass. The dorsal root ganglia from 1-3-day-old Sprague-Dawley rats were cultured above PPy membrane and observed by light or scanning electron microscopy. The PPy-silicone tube (PPy membrane on the inner surface of the silicone tube) also synthesized electrochemically was used to bridge across 10-mm sciatic nerve gap in rats. Twenty-four weeks after the operation to rats, the regenerated tissues were observed by electrophysiological and histological techniques. PPy extraction solution showed no evidence of acute and subacute toxicity, pyretogen, hemolysis, allergen, and mutagenesis, and the Schwann cells from the PPy extraction solution group showed better survival rate and proliferation rate as compared with the saline solution control group. The migration of the Schwann cells and the neurite extension from dorsal root ganglia on the surface of PPy membrane-coated glass was better than those of bare glass. There was only lightly inflammation during 6 months of the postoperation, when the PPy-silicone tube bridged across the gap of the transected sciatic nerve. The regeneration of nerve tissue in the PPy-silicone tube was slightly better than that in the plain silicone tube by means of electrophysiological and histological examination. The results of this study indicate that PPy has a good biocompatibility with rat peripheral nerve tissue and that PPy might be a candidate material for bridging the peripheral nerve gap.

Fabrication and properties of a porous chitin/chitosan conduit for nerve regeneration.

A porous, biodegradable, natural chitin/chitosan nerve conduit was constructed. Scanning electron microscopy confirmed that it was homogeneous and highly porous. FT-IR spectra showed that there were no residues arising from the preparation process in the conduit. Addition of chitin to the chitosan solution increased the mechanical strength and maximum tensile strength from 7.2 to 9.6 MPa. Preliminary animal tests indicated that porous chitin/chitosan conduits did not swell in vivo and were compatible with surrounding tissue.

[Detection of GGT-II by dot-ELISA with monoclonal antibody in the diagnosis of hepatocellular carcinoma].

BACKGROUND & OBJECTIVE: Hepatoma-specific gamma- glutamyltransferase isoenzyme II(GGT-II) is considered as the best hepatoma marker except alpha-fetoprotein (AFP), but there is no simple and easy method to determine it now. The purpose of this study was to explore the value of detection of GGT-II by dot-ELISA with monoclonal antibody in the diagnosis of hepatocellular carcinoma (HCC). METHODS: GGT-II was purified and then BALB/c mouse was immunized. The monoclonal antibody against GGT-II was raised by the hybridoma technique. Serum GGT-II was detected in 123 cases with hepatocellular carcinoma and 164 cases with various benign liver diseases using both dot-ELISA and electrophoresis simultaneously. RESULTS: The positive rate of serum GGT-II in HCC by dot-ELISA was 71.5%, which was not significantly different from that by electrophoresis (76.4%). However, the false positive rates of GGT-II by dot-ELISA in liver cirrhosis (23.7%) and chronic hepatitis (27.1%) were significantly higher than those by electrophoresis (10.0% and 8.4% for liver cirrhosis and chronic hepatitis, respectively). CONCLUSION: Detection of GGT-II by dot-ELISA with monoclonal antibody is helpful for the diagnosis of HCC, but its diagnostic specificity deserves to be improved.