Quality of life and its influencing factors on children with asthma in China: a comparative study before and during the COVID-19 pandemic.

OBJECTIVE: This study compares the level of quality of life (QoL) and its influencing factors on children with asthma before and during the COVID-19 pandemic. METHODS: The study carried out cross-sectional surveys on children with asthma and their parents in China before and during the epidemic. Data were collected using a demographic questionnaire, the Family Management Scale for Children with Asthma (FMSCA), and the Pediatric Asthma Quality of Life Questionnaire (PAQLQ). Participants from before the epidemic were matched by their propensity score in a 1:1 ratio with individuals from during the epidemic. The level of QoL of children with asthma was subsequently analyzed. Both univariate analysis and multiple linear regression were employed to identify the influencing factors. RESULTS: Compared to their level before the epidemic, the total score of PAQLQ and its three dimensions decreased during the epidemic. Regression analysis revealed that before the epidemic, the total score of PAQLQ was significantly associated with follow-up visits, attendance of asthma lectures, and the total score of FMSCA (p < 0.05). During the epidemic, the total score of the PAQLQ was significantly associated with three dimensions of the FMSCA (future expectation, children identity, and views of condition), and two classifications of the family management styles (FMS) (enduring and accommodating) (p < 0.05). CONCLUSION: The QoL of children with asthma deteriorated during the epidemic. Influencing factors changed during the epidemic, with more emphasis on the family environment. Future intervention strategies need to take into account the development of interactions between children and environmental forces.

Development and Validation of the Parents' Health Literacy Scale for Children with Asthma (PHLSCA).

OBJECTIVE: This study aimed to develop and validate an instrument to assess the health literacy of parents of children with asthma in a Chinese context. METHODS: The preliminary Parents' Health Literacy Scale for Children with Asthma (PHLSCA) was developed based on a literature review and refined to 45 items through two rounds of expert consultation using the Delphi method. A total of 481 parents of children with asthma were recruited from seven hospitals across four provinces in China between February and April 2019. Principal component analysis (PCA) and confirmatory factor analysis were conducted to evaluate the structural and construct validity of the scale. RESULTS: The development and validation processes led to a 38 items scale comprising three subscales, namely: Health Knowledge (11 items), Health Skills (19 items) and Health Behavior (8 items). The scale demonstrated good reliability, with an internal consistency of Cronbach's α = 0.956 and a split-half reliability of r = 0.887 (p < 0.01). The Item Content Validity Index (I-CVI) ranged from 0.81 to 1.00, and the Scale-CVI was 0.842. The correlation coefficients and factor analysis results indicated good construct validity, with the factors explaining 59.33% to 62.90% of the variance in each subscale. CONCLUSIONS: The final version of the questionnaire (PHLSCA) has been demonstrated to be a valid and reliable tool for assessing the health literacy of parents of Chinese children with asthma.

Metabolic Profiling for Unveiling Mechanisms of Kushenol F against Imiquimod-Induced Psoriasis with UHPLC/MS Analysis.

Psoriasis is a common chronic immune-mediated inflammatory skin disorder. Sophora flavescens Alt. (S. flavescens) has been widely acknowledged in the prevention and treatment of psoriasis. Kushenol F (KSCF) is a natural isopentenyl flavonoid extracted from the root of S. flavescens. We aimed to investigate the effect and mechanism of KSCF on imiquimod (IMQ)-induced psoriasis-like skin lesions in mice. A mouse model of psoriasis was induced with 5% IMQ for 5 days, and the mice were given KSCF dermally for 5 days. Changes in skin morphology, the psoriasis area, the severity index (PASI), and inflammatory factors of psoriasis-like skin lesions were evaluated. Metabolites in the psoriasis-like skin lesions were analyzed with ultra-high-performance liquid chromatography/mass spectrometry followed by a multivariate statistical analysis to identify the differential metabolites and metabolic pathway. The results of the present study confirmed that KSCF significantly reduced PASI scores, epidermal thickening, and epidermal cell proliferation and differentiation. KSCF also reduced the levels of interleukin (IL)-1ß, IL-6, IL-8, IL-17A, IL-22, IL-23, and tumor necrosis factor (TNF)-α in the injured skin tissues while increasing IL-10 content. KSCF significantly regulated metabolites in the skin samples, and a total of 161 significant metabolites were identified. These differential metabolites involved sphingolipid and linoleic acid metabolism and steroid hormone biosynthesis. Collectively, KSCF inhibited the inflammatory response to prevent IMQ-induced psoriasis-like skin lesions in mice by call-backing the levels of 161 endogenous metabolites and affecting their related metabolic pathways. KSCF has the potential to be developed as a topical drug for treating psoriasis symptoms.

Anti-fatigue effect of traditional Chinese medicines: A review.

A third of the world's population suffers from unexplained fatigue, hugely impacting work learning, efficiency, and health. The fatigue development may be a concomitant state of a disease or the side effect of a drug, or muscle fatigue induced by intense exercise. However, there are no authoritative guides or clinical medication recommendations for various fatigue classifications. Traditional Chinese medicines (TCM) are used as dietary supplements or healthcare products with specific anti-fatigue effects. Thus, TCM may be a potential treatment for fatigue. In this review, we outline the pathogenesis of fatigue, awareness of fatigue in Chinese and western medicine, pharmacodynamics mechanism, and substances. Additionally, we offer a comprehensive summary of fatigue and forecast the potential effect of novel herbal-based medicines against fatigue.

TIM3+ cells in gastric cancer: clinical correlates and association with immune context.

BACKGROUND: T cell immunoglobulin and mucin domain-containing protein 3 (TIM3) is a crucial immune checkpoint and is considered as an emerging target for cancer treatment. However, the clinical significance and immune-related role of TIM3+ cells in gastric cancer remain unknown. This study aimed to investigate the clinical significance of tumour-infiltrating TIM3+ cells and their association with immune contexture in gastric cancer. METHODS: This study enrolled three cohorts, including 436 tumour tissue microarray specimens and 58 fresh tumour tissues of gastric cancer patients from Zhongshan Hospital, and 330 transcriptional data from The Cancer Genome Atlas. TIM3+ cells and their association with CD8+ T cells were evaluated by immunohistochemistry and flow cytometry analyses. Kaplan-Meier curves, Cox model and interaction test were performed to assess clinical outcomes. RESULTS: Tumour-infiltrating TIM3+ cells' high subgroups experienced poorer overall survival and disease-free survival and predicted inferior therapeutic responsiveness to fluorouracil-based adjuvant chemotherapy. TIM3 indicated CD8+ T cell dysfunction, which impeded chemotherapeutic responsiveness. Besides, HAVCR2 messenger RNA expression was associated with specific molecular characteristics. CONCLUSIONS: The abundance of tumour-infiltrating TIM3+ cells could identify an immunoevasive subtype gastric cancer with CD8+ T cell dysfunction, suggesting that TIM3 might serve as a promising target for immunotherapy in gastric cancer.

Poor Clinical Outcomes and Immunoevasive Contexture in Intratumoral IL-10-Producing Macrophages Enriched Gastric Cancer Patients.

OBJECTIVE: To investigate the clinical significance of IL-10+ tumor-associated macrophages (TAMs) in gastric cancer. BACKGROUND: Due to the plasticity and diversity of TAMs, it is necessary to phenotypically and functionally classify subsets of TAMs to better understand the critical role of TAMs in cancer progression. TAMs expressing interleukin-10 (IL-10) have been found to facilitate immune evasion in many malignancies, but the role of IL-10+ TAMs in gastric cancer remains obscure. METHODS: Four hundred and sixty-eight tumor tissue microarray specimens, 52 fresh tumor tissue samples of gastric cancer patients from Zhongshan Hospital, and data of 298 gastric cancer patients from the Cancer Genome Atlas (TCGA) were analyzed. IL-10+ TAM level and immune contexture were examined by CIBERSORT, immunohistochemistry, and flow cytometry. Clinical outcomes were analyzed by Kaplan-Meier curves and Cox model. RESULTS: Gastric cancer patients with high IL-10+ TAM infiltration exhibited poor prognosis and inferior therapeutic responsiveness to fluorouracil-based adjuvant chemotherapy. IL-10+ TAM infiltration yielded an immunoevasive tumor microenvironment featured by regulatory T cell infiltration and CD8+ T cell dysfunction. The combinational analysis of IL-10+ TAM and CD8+ T cell infiltration stratified patients into distinct risk groups with different clinical outcomes. Moreover, IL-10+ TAM infiltration was correlated with tumor-intrinsic characteristics including EBV status, PD-L1 expression, and genome stability in gastric cancer. CONCLUSIONS: This study revealed that IL-10+ TAMs might drive an immunoevasive microenvironment and determine poor prognosis and inferior therapeutic responsiveness to fluorouracil-based adjuvant chemotherapy, indicating IL-10+ TAMs could be applied as a potential target for immunotherapeutic approach in gastric cancer.

Intratumoral Foxp3+RORγt+ T cell infiltration determines poor prognosis and immunoevasive contexture in gastric cancer patients.

BACKGROUND: Foxp3+RORγt+ T cells possess both characteristics of regulatory T cells and T helper 17 cells and show significant immunoregulatory functions in autoimmune diseases. However, the role and clinical significance of Foxp3+RORγt+ T cells in gastric cancer remains unclear. METHODS: We enrolled 452 gastric cancer tissue microarray samples and 60 fresh tumor tissue samples from Zhongshan Hospital. The infiltration of Foxp3+RORγt+ T cells and immune contexture were examined by immunohistochemistry and flow cytometry. Survival analyses of patient subgroups were conducted by Kaplan-Meier curves, log-rank test and Cox proportional model. RESULTS: High infiltration of Foxp3+RORγt+ T cells predicted poor overall survival (P = 0.0222 and 0.0110) and inferior therapeutic response (P = 0.003 for interaction) in gastric cancer. Foxp3+RORγt+ T cells were associated with impaired effective function of CD8+ T cells featured by decreased interferon-γ, granzyme B and CD107a expression. Co-evaluation of Foxp3+RORγt+ T cells and CD8+ T cells could predict survival outcomes and chemotherapeutic responsiveness more precisely. CONCLUSIONS: We found that Foxp3+RORγt+ T cells could potentially attenuate effective functions of CD8+ T cells and led to adverse survival outcomes and inferior chemotherapeutic responsiveness. Moreover, the novel co-evaluation system might be useful for prognosis prediction for appropriate treatment in gastric cancer. NOVELTY AND IMPACT STATEMENTS: Clinical significance of Foxp3+RORγts+ T cells has not been studied in gastric cancer. Herein, we investigated the prognostic value of Foxp3+RORγt+ T cells in 452 patients. We demonstrated that intratumoral Foxp3+RORγt+ T cell infiltration was a prognostic biomarker for overall survival and the identification of patients might benefit from post-gastrectomy 5-fluorouracil. These findings allow a more precise stratification upon the co-evaluation with CD8+ T cells to better clinical management for patients who would benefit from 5-fluorouracil.

Different color regulation mechanism in willow barks determined using integrated metabolomics and transcriptomics analyses.

BACKGROUND: The rich yellow-orange to vividly deep red bark of willow (Salix spp.) branches have high ornamental and economic value. However, the mechanism underlying the regulation of willow branch color remains unknown. Therefore, we performed metabolomics and transcriptomics analyses of purple, green, and red willow barks to elucidating the mechanisms regulating color development. RESULTS: Seven anthocyanins were isolated; pelargonidin, petunidin 3-O-rutinoside, and cyanin chloride were the most abundant in red bark, whereas pelargonin chloride was most abundant in purple bark. The green bark contained the highest level of malvidin; however, the malvidin level was not significantly higher than in the red bark. The purple bark contained the largest amount of canthaxanthin, a carotenoid pigment. The integrated pathways of flavonoid biosynthesis, carotenoid biosynthesis, and porphyrin and chlorophyll metabolism were constructed for the willow barks. Among the three barks, the expression of the structural genes ANS, ANR, and BZ1, which are involved in anthocyanin synthesis, was the highest in red bark, likely causing anthocyanin accumulation. The expression of CrtZ, which participates in the carotenoid pathway, was the highest in purple bark, likely leading to canthaxanthin accumulation. The high expression of DVR, POR, and CRD1 may be associated with green pigment synthesis in the chlorophyll biosynthesis pathway. CONCLUSIONS: Purple bark color is co-regulated by anthocyanins and carotenoids, whereas red bark is characterized by anthocyanin accumulation and chlorophyll degradation. The green pigment is regulated by maintaining chlorophyll synthesis. BZ1 and CrtZ are candidate genes regulating anthocyanin and canthaxanthin accumulation in red and purple barks respectively. Collectively, our results may facilitate the genetic breeding and cultivation of colorful willows with improved color and luster.

Decoding hexanitrobenzene (HNB) and 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) as two distinctive energetic nitrobenzene compounds by machine learning.

Energetic materials (EMs) are a group of special energy materials, and it is generally full of safety risks and generally costs much to create new EMs. Thus, machine learning (ML)-aided discovery becomes highly desired for EMs, as ML is good at risk and cost reduction. This work decodes hexanitrobenzene (HNB) and 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) as two distinctive energetic nitrobenzene compounds by ML, in combination with theoretical calculations. Based on a series of highly accurate models of density, heat of formation, bond dissociation energy and molecular flatness, the ML predictions show that HNB is the most energetic among ∼370 000 000 single benzene ring-containing compounds, while TATB possesses a moderate energy content and very high safety, as determined experimentally. This work exhibits the significant power of ML and presents an instructive procedure for using it in the field of EMs. The ML-aided design and highly efficient synthesis and fabrication combined strategy is expected to accelerate the discovery of new EMs.

Neurological and psychiatric presentations associated with COVID-19.

The objective is to investigate coronavirus disease 2019 (COVID-19)-associated neurological and psychiatric effects and explore possible pathogenic mechanisms. This study included 77 patients with laboratory-confirmed COVID-19 in Wuhan, China. Neurological manifestations were evaluated by well-trained neurologists, psychologists, psychiatric presentations and biochemical changes were evaluated using the Generalized Anxiety Disorder 7-item scale, Patient Health Questionnaire-9, Brief Psychiatric Rating Scale, and electronic medical records. Eighteen (23.4%) patients presented with neurological symptoms. Patients with neurological presentations had higher urea nitrogen, cystatin C, and high-sensitivity C-reactive protein levels and lower basophil counts. Among them, patients with muscle involvement had higher urea nitrogen and cystatin C levels but lower basophil counts. In addition, patients with psychiatric presentations were older and had higher interleukin (IL)-6 and IL-10 levels and higher alkaline phosphatase, R-glutamate transferase, and urea nitrogen levels. Moreover, patients with anxiety had higher IL-6 and IL-10 levels than those without, and patients with moderate depression had higher CD8 + T cell counts and lower CD4 + /CD8 + ratios than other patients. This study indicates that the central nervous system may be influenced in patients with COVID-19, and the pathological mechanisms may be related to direct virus invasion of the central nervous system, infection-mediated overreaction of the immune system, and aberrant serum pro-inflammatory factors. In addition, basophils and cystatin C may also play important roles during these pathological processes. Our findings suggest that neurological and psychiatric presentations should be evaluated and managed in patients with COVID-19. Further studies are needed to investigate the underlying mechanisms.

Lymphocyte-activation gene 3 expression associates with poor prognosis and immunoevasive contexture in Epstein-Barr virus-positive and MLH1-defective gastric cancer patients.

Lymphocyte activation gene 3 (LAG-3) is a transmembrane immune checkpoint that facilitates immune escape via suppressing T-cell-mediated anti-tumor immunity. The role of LAG-3 in gastric cancer is little known. Consequently, we assessed the clinical significance of LAG-3 in gastric cancer. In our study, patients with gastric cancer from Zhongshan Hospital (n = 464) and data from the Asian Cancer Research Group (n = 300) were analyzed. LAG-3+ cell infiltration and other immune contexture in gastric cancer were detected by immunohistochemistry. Kaplan-Meier curves and log-rank test were used for survival analyses. Intratumoral LAG-3+ cells mainly accumulated in Epstein-Barr virus (EBV)-positive (EBV subtype) and MLH1-defective (dMLH1 subtype) gastric cancer. Furthermore, LAG-3+ cell infiltration was strongly associated with inferior clinical outcomes in patients with these two subtypes of gastric cancer. Moreover, we found intratumoral LAG-3+ cell high infiltration was associated with an immunoevasive contexture featured by decreased IFN-γ+ cells and perforin-1+ cells, but increased regulatory T cells and M2-like macrophages in EBV/dMLH1 subtype of gastric cancer. LAG-3 was a poor prognostic factor and might be a potential immunotherapeutic target in EBV-positive and MLH1-defective gastric cancer.

CD47 expression in gastric cancer clinical correlates and association with macrophage infiltration.

BACKGROUND: CD47 has been identified as an innate immune checkpoint and found to be associated with inferior survival in various types of cancer. However, the critical role of CD47 in gastric cancer and its association with tumor associated macrophages remain unclear. METHODS: Tumor tissues of gastric cancer from Zhongshan Hospital and data from GSE62254, GSE84437 and TCGA datasets were analyzed. Immunohistochemistry was performed to detect the expression of CD47, CD11c, CD163 and CD68 in gastric cancer tissues. Kaplan-Meier curves and Cox model were used for comparing the clinical outcomes of patients belonging to different subgroups. RESULTS: Gastric cancer patients with high CD47 expression exhibited poor prognosis and inferior therapeutic responsiveness to fluorouracil-based adjuvant chemotherapy (ACT). A positive correlation was found between M1-polarized macrophage infiltration and CD47 expression in gastric cancer; however, the prognostic value of M1-polarized macrophages was attenuated in CD47-high gastric cancer patients. Moreover, we found that CD47 mRNA level was enriched in microsatellite-instable (MSI) subtype of gastric cancer and associated with ARID1A mutation and FGFR2 signaling pathway activation. CONCLUSIONS: Aberrant CD47 expression represented an independent predictor for adverse survival outcome and ACT resistance in gastric cancer. Targeting CD47 might be a promising strategy for gastric cancer patients.

Clinical Outcomes and Immune Metrics in Intratumoral Basophil-Enriched Gastric Cancer Patients.

BACKGROUND: Accumulation of basophils has been reported in several malignancies. In gastric cancer, the relation between tumor-infiltrating basophils and patient overall survival and chemotherapeutic responsiveness still remains obscure. OBJECTIVE: We aimed to investigate the postoperative prognostic and predictive significance of basophils to survival outcomes and chemotherapeutic responsiveness in resectable gastric cancer. METHODS: The study enrolled two independent patient data sets with 448 gastric cancer patients overall. Basophils were evaluated with the use of immunohistochemistry (IHC) staining, and the correlation with clinicopathological characteristics, survival outcomes, and responsiveness to fluorouracil-based adjuvant chemotherapy (ACT) were investigated. Additionally, IHC was applied to characterize immune contexture in gastric cancer. RESULTS: In either the discovery or validation data sets, accumulated basophils indicated poorer prognosis, and tumor-infiltrating basophils were identified as an independent adverse prognostic factor by multivariate analysis. Furthermore, tumor-infiltrating basophils determined significantly inferior therapeutic responsiveness to fluorouracil-based ACT in patients with stage III tumors. In addition, the abundance of basophils was correlated with an immunoevasive contexture characterized by M2-polarized macrophage infiltration. Moreover, our findings indicated elevated interleukin-4 expression but decreased interferon-γ expression in the high-basophils subgroup. CONCLUSIONS: Tumor-infiltrating basophils in gastric cancer were identified as an independent adverse prognosticator, and also predicted inferior chemotherapeutic responsiveness, which identified those patients in need of much more individualized postoperative adjuvant therapy and more stringent follow-up. Furthermore, the infiltration of basophils was associated with immunoevasive tumor microenvironment, which might be a potential immunotherapeutic target for gastric cancer.

Effects of heavy metals speciations in sediments on their bioaccumulation in wild fish in rivers in Liuzhou-A typical karst catchment in southwest China.

Although fish are widely confirmed to be susceptible to heavy metals (HMs) contamination in sediments, this bioconversion haven't been detailed. This is especially the case in karst areas, where HMs are less stably retained in the sediments and are more bioavailable. Therefore, we surveyed representative karst rivers in Liuzhou, China, in order to study the relationship between the speciations of seven HMs in the sediments with their bioaccumulation in wild fish. The results showed that the HMs in sediments are all below their permissible exposure limit (PEL), but Cd and Zn are significantly higher than soil basline. Most HMs are in residual fraction, while their exchangeable fractions are present in extremely low proportions. The concentration of Zn, Cr and Cd in some fish are above their maximum recommended limit (MRL). The concentrations of most of the HMs in the fish are significantly correlated with the levels in the sediments and given the higher correlation coefficients for their carbonate-bound phase, this phase can be seen to play a critical role in HMs bioconversion. However, the presence of this phase in low proportions enables other phases, especially oxidizable form, to play a greater role in HMs bioaccumulation. Apart from Do, HMs in the fish samples are significantly correlated with multiple environmental factors, demonstrating environmental fluctuations can manipulate HMs bioconversion from sediments; however, their significance depend heavily on the proportion of particular species. HMs in reducible and oxidizable fraction are more important in regulating, rather than promoting, their bioconversion during environmental fluctuations. Fluctuations in EC, TDS and pH can increase the impacts of HMs in carbonate-bound fraction on their bioconversion. Given the higher background values of EC and TDS and lower pH values during the monsoon period, careful attention should be paid to the increased bioconversion of HMs in karst rivers during this season.

[Overview and prospect of research and development cooperation in traditional medicine between China and Thailand].

Under the background of the Belt and Road Initiative, the exchange of traditional medicine has become inevitable. China and Thailand are amicable neighbors, and the cooperation between the two countries in the field of traditional medicine has become increasingly close in recent years. Nevertheless, on account of the differences in culture, region, politics, economy and so on, the two countries have common features and unique characteristics in the theoretical system of traditional medicine, quality standard control of medicinal materials, research and development and use of medicinal materials. This paper summarizes the similarities and differences as well as the development opportunities of traditional medicine between China and Thailand. The specific content involves the development history, resources, and use of medicinal resources in Thailand, the main achievements and existing problems of modern research of Thai medicine, the spread and development of Chinese medicine in Thailand, and the spread and development of Thai medicine in China. Furthermore, the paper outlines the recent situation of traditional medicine interflow and cooperation between the two countries, and predicts the prospects for cooperation and development of traditional medicine between China and Thailand in the context of the Belt and Road Initiative, especially in the joint research and development and the improvement of quality standards of important medicinal plant varieties commonly used by the two countries and circulated across the border. Through the exchange and mutual learning, we can step up the traditional medicine cooperation between China and Thailand, which will provide advantageous conditions for the safety of medicine use as well as political and social stability between the two countries.

High throughput scanning of dimer interactions to facilitate confirmation of the molecular stacking mode: a case of 1,3,5-trinitrobenzene and its amino-derivatives.

Exactly predicting the packing structures of a given molecule is a crucial topic in crystal engineering, while it remains still challenging, as it requires huge calculations, largely above common computation cost and time limitations. However, current progress in high throughput calculations makes the fast screening of structures and properties feasible. In the present work, we exemplify this by considering a special case of ascertainment of the molecular stacking mode and shear properties of energetic materials. Four energetic π-bonded molecules, 1,3,5-trinitrobenzene, 2,4,6-trinitroaniline, 1,3-diamino-2,4,6-trinitrobenzene and 2,4,6-triamino-1,3,5-trinitrobenzene, with a different number of H atoms replaced by amino groups, are adopted as samples to scan the potential energy surfaces (PESs) of dimers through high throughput calculations. It is found that the parallel stacking mode is the most energetically favored, followed by the T-shaped, coplanar and crossing ones. Such an energetically favored stacking mode is observed in all related π-stacked crystal structures at ambient conditions or low temperatures. It shows that the stacking mode can be ascertained through the PES scanning of dimers, and thereby, the stacking structures and properties related to the stacking mode, like mechanical anisotropism, can be quickly screened by means of high throughput calculations.

Reversible intramolecular hydrogen transfer: a completely new mechanism for low impact sensitivity of energetic materials.

The intramolecular H transfer of energetic NO2-compounds has been recognized as a possible primary step in triggering molecular decomposition for a long time. Nevertheless, studies on H transfer in different complex situations are limited, lacking a comprehensive understanding of its role in NO2-compounds. In this work, twenty intramolecular H transfer reactions are studied for eighteen nitro compounds and compared with the NO2 partition in thermodynamics and kinetics. Three factors, including the high planarity of molecules, the short transfer distance between the target H and O atoms and the high protonation of the H atom are identified to facilitate H transfer. If H transfer is more kinetically favorable than NO2 partition, and if a reverse H transfer occurs with a barrier less than 30 kcal mol-1, we define it as a reversible one. In our study, for those impact insensitive nitro compounds with H50 larger than that of 2,4,6-trinitrotoluene, all of them are found to be accompanied with reversible H transfer, while the impact sensitive compounds are not. Accordingly, we propose that the reversible H transfer can effectively buffer the external stimuli against the molecular decomposition through chemical energy absorption/release. Beyond the conventional understanding that H transfer triggers molecular decomposition, this work builds a new correlation between reversible H transfer and the low impact sensitivity of energetic nitro-compounds.

Visual Semantic Landmark-Based Robust Mapping and Localization for Autonomous Indoor Parking.

Autonomous parking in an indoor parking lot without human intervention is one of the most demanded and challenging tasks of autonomous driving systems. The key to this task is precise real-time indoor localization. However, state-of-the-art low-level visual feature-based simultaneous localization and mapping systems (VSLAM) suffer in monotonous or texture-less scenes and under poor illumination or dynamic conditions. Additionally, low-level feature-based mapping results are hard for human beings to use directly. In this paper, we propose a semantic landmark-based robust VSLAM for real-time localization of autonomous vehicles in indoor parking lots. The parking slots are extracted as meaningful landmarks and enriched with confidence levels. We then propose a robust optimization framework to solve the aliasing problem of semantic landmarks by dynamically eliminating suboptimal constraints in the pose graph and correcting erroneous parking slots associations. As a result, a semantic map of the parking lot, which can be used by both autonomous driving systems and human beings, is established automatically and robustly. We evaluated the real-time localization performance using multiple autonomous vehicles, and an repeatability of 0.3 m track tracing was achieved at a 10 kph of autonomous driving.

Ionization and separation as a strategy for significantly enhancing the thermal stability of an instable system: a case for hydroxylamine-based salts relative to that for pure hydroxylamine.

Energetic ionic salts (EISs) are attracting extensive attention because of their ready preparation and some excellent properties and performances that are comparable to those of common explosives with neutral molecules. Hydroxylamine (HA) is protonated or ionized as H-HA+ and preferred to be introduced into EISs to form HA-based EISs with almost all kinds of anions since these EISs possess higher packing densities and thus more excellent detonation performances than others with the same anions. Moreover, relative to that of pure HA, the thermal stability of HA-based EISs is significantly enhanced. This significantly enhanced thermal stability can extend the application of HA via deprotonation of H-HA+ back to HA; however, the mechanism for stabilization of HA by salification remains unclear. Herein, we employed thermodynamic and kinetic calculations and molecular dynamics simulations to reveal the thermal stability mechanisms of many currently synthesized HA-based EISs and some previously reported EISs with inorganic anions as well as those of pure HA and its aqueous solution. As a result, we have found that the enhanced stability of HA-based EISs is mainly due to the ionization and separation of HA molecules themselves. That is, H-HA+, as an ionized product, is more molecularly stable than HA, with significantly strengthened covalent bonds. The separation of H-HA+ ions or HA molecules makes decomposition more difficult as decomposition initiation varies from bimolecular to unimolecular reactions of HA, with a significant increase in the energy barrier. We have, therefore, proposed a strategy for the stabilization of unstable systems, such as neutral N-rich energetic compounds, by ionization and separation to strengthen these systems and change the decomposition mechanism by increasing the energy barriers of trigger steps such that these barriers become more difficult to overcome, respectively.

[Mechanisms of histamine ameliorating memory impairment induced by pentylenetetrazole-kindling epilepsy in rats].

Objective: To investigate the effects of neuronal histamine on spatial memory acquisition impairment in rats with pentylenetetrazole-kindling epilepsy, and to explore its mechanisms. Methods: A subconvulsive dose of pentylenetetrazole (35 mg/kg) was intraperitoneally injected in rats every 48 h to induce chemical kindling until fully kindled. Morris water maze was used to measure the spatial memory acquisition of the rats one week after fully pentylenetetrazole-kindled, and the histamine contents in different brain areas were measured spectrofluorometrically. Different dosages of hitidine (the precursor of histamine), pyrilamine (H1 receptor antagonist), and zolantidine (H2 receptor antagonist) were intraperitoneally injected, and their effects on spatial memory acquisition of the rats were observed. Results: Compared with control group, escape latencies were significantly prolonged on Morris water maze training day 2 and day 3 in pentylenetetrazole-kindling epilepsy rats (all P<0.05); and the histamine contents in hippocampus, thalamus and hypothalamus were decreased significantly (all P<0.05). Escape latencies were markedly shortened on day 3 by intraperitoneally injected with histidine 500 mg/kg, and on day 2 and day 3 by intraperitoneally injected with histidine 1000 mg/kg in pentylenetetrazole-kindling epilepsy rats (all P<0.05). The protection of histidine was reversed by zolantidine (10 and 20 mg/kg), but not by pyrilamine. Conclusion: Neuronal histamine can improve the spatial memory acquisition impairment in rats with pentylenetetrazole-kindling epilepsy, and the activation of H2 receptors is possibly involved in the protective effects of histamine.