Mechanistic study of the competition between carbon dioxide reduction and hydrogen evolution reaction and selectivity tuning via loading single-atom catalysts on graphitic carbon nitride.

In the context of catalytic CO2 reduction (CO2RR), the interference of the inherent hydrogen evolution reaction (HER) and the possible selectivity towards CO have posed a significant challenge to the generation of formic acid. To address this hurdle, in this work, we have investigated the impact of different single-atom metal catalysts on tuning selectivity by employing density functional theory (DFT) calculations to scrutinize the reaction pathways. Single-atom catalysts supported on carbon-based systems have proven to be pivotal in altering both the activity and selectivity of the CO2RR. In this study, a series of single-atom-metal-loaded g-C3N4 monolayers (MCN, M = Ni, Cu, Zn, Ga, Cd, In, Sn, Pb, Ag, Au, Bi, Pd and Pt) were systematically examined. Through detailed DFT calculations, we explored their influence on reaction selectivity between the *COOH and *OCHO intermediates. Notably, NiCN favors the reaction via the *OCHO route, with a significantly lower rate-determining potential of 0.36 eV, which is approximately 73.5% lower than that of the CN system (1.36 eV). Most importantly, the Ni single-atom catalyst with lower coordination significantly enhances CO2 adsorption, promoting CO2RR over HER. Overall, this study, guided by DFT calculations, provides a theoretical prediction of how the selection of single-atom metal catalysts can effectively modulate the reaction pathway, thereby offering a potential solution for achieving high product selectivity in CO2RR.

Assembly-inspired multiferroicity with nontrivial Chern insulating phase from exohedral metallofullerenes.

Fullerene-assembled low-dimensional materials have been experimentally realized in polymorphic forms and have attracted significant interest very recently. Here, we predict a two-dimensional (2D) honeycomb lattice material TM2(C60)3 (TM = Cr, Mo, and W) assembled from exohedral metallofullerene clusters TM(C60)3 that could exhibit planar triangular geometries. According to first-principles calculations combined with Monte Carlo simulations, we suggest that these 2D assembled materials exhibit various exotic physical properties, including ferromagnetism, ferroelectricity, and quantum anomalous Hall effect. Interestingly, mechanical strains could effectively tune their magnetic moments and switch the conducting spin channel of the Dirac bands at the Fermi level. Our work provides a new cluster-assembly design strategy toward cluster-assembled 2D materials based on fullerene characters.

Lattice oxygen activation of MnO2 by CeO2 for the improved degradation of bisphenol A in the peroxymonosulfate-based oxidation.

The structure of MnO2 was modified by constructing the composites CeO2/ MnO2 via a facile hydrothermal method. The catalytic performance of optimal composite (Mn-Ce10) in peroxymonosulfate (PMS) activation for the degradation of bisphenol A (BPA) is approximately three times higher than that of MnO2 alone. The average valence of manganese in CeO2/MnO2 is lowered compared to MnO2, which induces the generation of more free radicals, such as OH and SO4•-. In addition, the composite exhibits a higher concentration of oxygen vacancies than MnO2, facilitating bondingwith PMS to produce more singlet oxygen (1O2). Moreover, the incorporation of CeO2 activates the lattice oxygen of MnO2, improving its oxidative ability. Consequently, approximately 48% of BPA decomposition in 10min is attributed to direct oxidation in the Mn-Ce10/PMS system, whereas only 36% occurs in 30min for the MnO2/PMS system. Simulation results confirm weakened Mn-O covalency and elongated Mn-O bonds due to the activation of lattice oxygen in CeO2/MnO2, demonstrating that PMS tends to be adsorbed on the composite rather than on MnO2. This work establishes a relationship between lattice oxygen and the degradation pathway, offering a novel approach for the targeted regulation of catalytic oxidation.

A theoretical study on hydrated sodium ion-phenylalanine clusters Na+(Phe)(H2O)n (n = 0-6; Phe = phenylalanine).

The cation-π interaction is of importance in many chemical and biological processes such as those involving protein geometries and functionals and ion channels. In this study, to understand the cation-π interaction between essential ions and protein in the water-aqueous environment, geometries, electronic structures, bonding properties, and dynamic stabilities of hydrated Na+-phenylalanine clusters Na+(Phe)(H2O)n (n = 0-6) were studied using density functional theory calculations and ab initio molecular dynamics simulations. After the addition of water molecules, Na+(Phe)(H2O)n structures change from a tridentate complex to quadridentate or pentadentate complexes while the cation-π interaction always exists. The fluctuation between quadridentate and pentadentate complexes results from the competition between cation-O bonding and hydrogen bonding. The charge analysis reveals that the positive charge is mainly located on the Na ion, whereas the further addition of water reduces the binding energy of water, electron affinity, and ionization potential. As the number of water molecules increases, the bonding interactions between the sodium ion and the remaining phenylalanine-water complex increase and correlate with the coordination number, in which the electrostatic interaction contributes more than the orbital interaction. The important orbital interaction terms come from the donation of the carboxyl and amino groups and water to the Na+ ion. Molecular dynamic simulations revealed that Na+(Phe)(H2O)6 is stable at 300 K.

A Pentagonal Defect-Rich Metal-Free Carbon Electrocatalyst for Boosting Acidic O2 Reduction to H2O2 Production.

Metal-free carbon-based materials are considered one of the most promising two-electron oxygen reduction reaction (2e- ORR) electrocatalysts for the green synthesis of hydrogen peroxide (H2O2). However, most reported carbon electrocatalysts perform much more effectively in alkalis than in acids. Herein, by creatively using fullerene (C60) as the precursor subject to ammonia treatment, we designed and synthesized a pentagonal defect-rich nitrogen-doped carbon nanomaterial (PD/N-C). It achieves outstanding ORR activity, 2e- selectivity, and stability in acidic electrolytes, surpassing the benchmark PtHg4 alloy catalyst. Impressively, the flow cell based on the PD/N-C catalyst achieves nearly 100% Faraday efficiency with a remarkable H2O2 yield, representing the best improvement among all the metal-free catalysts. Experimental and theoretical results reveal that such superb 2e- ORR performance of PD/N-C originates from the synergism between pentagonal defects and nitrogen dopants. This work presents an effective strategy for the design and construction of highly efficient acid-resistant carbon electrocatalysts for H2O2 production and beyond.

Optimizing outcomes, mechanisms, and recall of Cognitive Therapy for depression: Dose of constructive memory support strategies.

OBJECTIVE: Poor memory for treatment is associated with worse patient outcomes. Therapist use of constructive memory support strategies, which help patients actively engage with treatment content, may improve patient memory for treatment. We sought to identify the dose of constructive memory support needed to optimize treatment outcomes, mechanisms, and patient recall. METHOD: Adults with major depressive disorder (N = 178, mean age = 37.9, 63% female, 17% Hispanic or Latino/a) were randomized to Cognitive Therapy plus a Memory Support Intervention or Cognitive Therapy as usual. Because therapists from both groups used constructive memory support, treatment conditions were combined to maximize data. Depression and overall impairment were assessed before treatment, immediately post-treatment (POST), and six (6FU) and 12 months (12FU) after treatment. Patients completed measures of treatment mechanisms - utilization/competency in Cognitive Therapy skills - and treatment recall at POST, 6FU, and 12FU. Patient adherence to treatment was averaged across sessions. RESULTS: Using Kaplan-Meier Survival Analyses, the optimal dose of constructive memory support was eight uses per session (sensitivity analysis range: 5-12 uses). Pre-treatment depression symptoms and patient perceptions of treatment may impact the optimal dose. CONCLUSION: Eight uses of constructive memory support by therapists per session may optimize treatment outcomes, mechanisms, and recall over the long-term.

Serial Mediators of Memory Support Strategies Used With Cognitive Therapy for Depression: Improving Outcomes Through Patient Adherence and Treatment Skills.

Patient memory for treatment is poor. Memory support strategies can be integrated within evidence-based psychological treatments to improve patient memory for treatment, and thereby enhance patient outcomes. The present study evaluated possible mechanisms of these memory support strategies. Specifically, we tested whether therapist use of memory support strategies indirectly predicts improved patient outcomes via serial improvements in (a) patient adherence throughout treatment and (b) patient utilization and competency of treatment skills. Adults with major depressive disorder (N = 178, mean age = 37.93, 63% female, 17% Hispanic or Latino) were randomized to Cognitive Therapy plus a Memory Support Intervention or Cognitive Therapy-as-usual. Because therapists from both treatment groups used memory support strategies, data from conditions were combined. Blind assessments of depression severity and overall impairment were conducted before treatment, immediately posttreatment (POST), at 6-month follow-up (6FU), and at 12-month follow-up (12FU). Patient adherence to treatment was rated by therapists and averaged across treatment sessions. Patients completed measures of treatment mechanisms-namely, utilization and competency in cognitive therapy skills-at POST, 6FU, and 12FU. Results of serial mediation models indicated that more therapist use of memory support predicted lower depression severity at POST, 6FU, and 12FU indirectly and sequentially through (a) increased patient adherence during treatment and (b) more utilization and competency of Cognitive Therapy skills at POST, 6FU, and 12FU. The same patterns were found for serial mediation models predicting lower overall impairment at POST, 6FU, and 12FU. Together, boosting memory for treatment may represent a promising means to enhance pantreatment mechanisms (i.e., adherence and treatment skills) as well as patient outcomes.

Understanding electronic structures, chemical bonding, and fluxional behavior of Lu2@C2n (2n = 76-88) by a theoretical study.

Endohedral metal-metal-bonding fullerenes, in which encapsulated metals form covalent metal-metal bonds inside, are an emerging class of endohedral metallofullerenes. Herein, we reported quantum-chemical studies on the electronic structures, chemical bonding, and dynamic fluxionality behavior of endohedral metal-metal-bonding fullerenes Lu2@C2n (2n = 76-88). Multiple bonding analysis approaches, including molecular orbital analysis, the natural bond orbital analysis, electron localization function, adaptive natural density partitioning analysis, and quantum theory of atoms in molecules, have unambiguously revealed one two-center two-electron σ covalent bond between two Lu ions in fullerenes. Energy decomposition analysis with the natural orbitals for chemical valence method on the bonding nature between the encapsulated metal dimer and the fullerene cage suggested the existence of two covalent bonds between the metal dimer and fullerenes, giving rise to a covalent bonding nature between the metal dimer and fullerene cage and a formal charge model of [Lu2]2+@[C2n]2-. For Lu2@C76, the dynamic fluxionality behavior of the metal dimer Lu2 inside fullerene C76 has been revealed via locating the transition state with an energy barrier of 5 kcal/mol. Further energy decomposition analysis calculations indicate that the energy barrier is controlled by a series of terms, including the geometric deformation energy, electrostatic interaction, and orbital interactions.

Efficacy predictors of third-generation cephalosporins in treating spontaneous bacterial peritonitis.

OBJECTIVE: Third-generation cephalosporins (3rd GCs) have recently become controversial as the first-line strategy for empirical spontaneous bacterial peritonitis (SBP) treatment. This study aimed to identify SBP treatment efficacy predictors of 3rd GCs. METHODS: In this retrospective cohort study, 279 cirrhosis patients with SBP who received 3rd GC monotherapy for initial empirical treatment from 2013 to 2019 were included. Nonresponse was defined as a decreased ascites polymorphonuclear (PMN) count < 25% from baseline after 48 hours of antibacterial treatment. Multivariate regression analysis was used to identify efficacy predictors of 3rd GCs in treating SBP. Kaplan-Meier analysis was used to evaluate survival data. RESULTS: The nonresponder group included 120 patients with no response, and the responder group included 159 patients with responses. The response rate to 3rd GCs was 57.0% among all patients. The common pathogens were Escherichia coli (40.6%), Staphylococcus (15.6%), Klebsiella pneumonia (12.5%), and Streptococcus (12.5%) in 32 ascites culture isolates. Nosocomial SBP (NSBP) (odds ratio [OR]: 2.371, 95% confidence interval [CI]: 1.323-4.249, P = .004), pneumonia (OR: 11.561, 95% CI: 1.876-71.257, P = .008), recurrent SBP (OR: 3.386, 95% CI: 1.804-6.357, P < .001), platelet count (≥113.5 × 109/L) (OR: 3.515, 95% CI: 1.973-6.263, P < .001), and ascites PMN count (≤0.760 × 109/L) (OR: 4.967, 95% CI: 2.553-9.663, P < .001) were independent predictors of nonresponse to 3rd GCs against SBP. Survival plot analysis at 30 days showed worse survival for the nonresponders (P = .003). CONCLUSION: NSBP, pneumonia, recurrent SBP, increased platelet count, and lower ascites PMN count were independent predictors of nonresponse to 3rd GC in treating SBP. Nonresponse to initial antibiotic treatment was associated with worse survival.

Modulation of Structure and Optical Property of Nitrogen-Incorporated VO2 (M1) Thin Films by Polyvinyl Pyrrolidone.

VO2, as a promising material for smart windows, has attracted much attention, and researchers have been continuously striving to optimize the performance of VO2-based materials. Herein, nitrogen-incorporated VO2 (M1) thin films, using a polyvinylpyrrolidone (PVP)-assisted sol-gel method followed by heat treatment in NH3 atmosphere, were synthesized, which exhibited a good solar modulation efficiency (ΔTsol) of 4.99% and modulation efficiency of 37.6% at 2000 nm (ΔT2000 nm), while their visible integrated transmittance (Tlum) ranged from 52.19% to 56.79% after the phase transition. The crystallization, microstructure, and thickness of the film could be regulated by varying PVP concentrations. XPS results showed that, in addition to the NH3 atmosphere-N doped into VO2 lattice, the pyrrolidone-N introduced N-containing groups with N-N, N-O, or N-H bonds into the vicinity of the surface or void of the film in the form of molecular adsorption or atom (N, O, and H) filling. According to the Tauc plot, the estimated bandgap of N-incorporated VO2 thin films related to metal-to-insulator transition (Eg1) was 0.16-0.26 eV, while that associated with the visible transparency (Eg2) was 1.31-1.45 eV. The calculated Eg1 and Eg2 from the first-principles theory were 0.1-0.5 eV and 1.4-1.6 eV, respectively. The Tauc plot estimation and theoretical calculations suggested that the combined effect of N-doping and N-adsorption with the extra atom (H, N, and O) decreased the critical temperature (τc) due to the reduction in Eg1.

Unraveling the effects of linker substitution on structural, electronic and optical properties of amorphous zeolitic imidazolate frameworks-62 (a-ZIF-62) glasses: a DFT study.

Zeolitic imidazolate frameworks (ZIFs), as one sub-family of metal-organic frameworks (MOFs), are a new class of glass formers. Among them, one termed as ZIF-62 [Zn(Im)2-x (bIm) x ], has great glass-forming ability compared with other ZIFs. Yet very few reports provide us with information about this glass from the computational point of view. In order to explore and have a deeper understanding of the effects of mixing organic ligands on the fundamental properties, we systematically investigate the electronic, intrinsic bonding and optical properties of amorphous ZIF-62 (a-ZIF-62) glass with density functional theory (DFT) calculation. Here we construct six amorphous ZIF-62 (a-ZIF-62) models with the ratio of bIm/(Im + bIm) ranging from 0 to 33.5%. These models are constructed based on a near perfect continuous random network model with over one thousand atoms originated from silica glass. They all keep a short range order but lack a long range order. As the concentration of bIm increases, our results show that the internal cohesion of a-ZIF-62 increases, indicating a strong network connectivity. Especially, for the first time we reveal that an obvious mid-band emerges in the conduction band due to the addition of bIm ligands. This further leads to alternation in the dielectric function. The calculated refractive index increases with an increase in the content of bIm ligands, which agrees well with the experimental results. The present results help us have a deeper understanding of the linker ratio effects on the various properties of amorphous ZIF glass and shed light on other ways to tune the properties of amorphous ZIF glass.

Correction: Unraveling the effects of linker substitution on structural, electronic and optical properties of amorphous zeolitic imidazolate frameworks-62 (a-ZIF-62) glasses: a DFT study.

[This corrects the article DOI: 10.1039/C9RA09977H.].

Double contrast-enhanced ultrasonography of a small intestinal neuroendocrine tumor: a case report of a recommendable imaging modality.

A 57-year-old male presenting with spontaneously relieved abdominal cramp and distension was admitted to the West China Hospital. The diagnosis remained unclear after colonoscopy and computed tomography. Double contrast-enhanced ultrasonography was then performed and a neoplasm in the small intestine was suspected, supported by a thin-section computed tomography and positron emission tomography/computed tomography. This was confirmed pathologically after surgery to be a small intestinal G1 neuroendocrine tumor. Surgery was performed to remove approximately 25 cm of small bowel and a 3-cm solid mass located in the mesentery. The patient had a complete recovery and was tumor-free at the final follow-up. Small intestinal tumors including neuroendocrine tumors have always posed a diagnostic challenge. This case indicated that double contrast-enhanced ultrasonography is feasible in detection of small intestinal neuroendocrine tumors, and it may be an advisable approach assisting diagnosis of small intestinal tumors.

One-stage posterior approach for treating multilevel noncontiguous thoracic and lumbar spinal tuberculosis.

OBJECTIVES: Multilevel noncontiguous thoracic and lumbar spinal tuberculosis (MNST) is a relatively rare entity. The objective of this retrospective study was to investigate whether a technique involving a one-stage posterior debridement and decompression, combined with an intervertebral fusion and posterior instrumentation, is effective for treating MNST. METHODS: Thirteen patients, with an average age of 40.69 (18-67) years, who had MNST and were surgically treated in our department from January 2008 to October 2013, were reviewed. RESULTS: The average follow-up time was 37.54 ± 10.49 (19-58) months. The mean Cobb angle range was 15.69° ± 00A09.09° (-3° to 33°). The mean erythrocyte sedimentation rate (ESR) was 47.69 ± 9.30 mm/h (range 30-62 mm/h) before the operation. Neurological deficits were evaluated using the Frankel grade system. The mean Cobb angle decreased to 6.92° ± 3.93° postoperatively. Three months after the operation, the Cobb angle was 7.54° ± 4.35°, and the average ESR was 10.38 ± 4.54 mm/h that was normal for all cases in this retrospective observational study. Solid fusion was achieved in all cases. No severe complications occurred. CONCLUSIONS: The study demonstrated that a one-stage posterior debridement and decompression, combined with an intervertebral fusion and posterior instrumentation, was effective for treating MNST.

Tuning and Locking the Localized Surface Plasmon Resonances of CuS (Covellite) Nanocrystals by an Amorphous CuPd x S Shell.

We demonstrate the stabilization of the localized surface plasmon resonance (LSPR) in a semiconductor-based core-shell heterostructure made of a plasmonic CuS core embedded in an amorphous-like alloyed CuPd x S shell. This heterostructure is prepared by reacting the as-synthesized CuS nanocrystals (NCs) with Pd2+ cations at room temperature in the presence of an electron donor (ascorbic acid). The reaction starts from the surface of the CuS NCs and proceeds toward the center, causing reorganization of the initial lattice and amorphization of the covellite structure. According to density functional calculations, Pd atoms are preferentially accommodated between the bilayer formed by the S-S covalent bonds, which are therefore broken, and this can be understood as the first step leading to amorphization of the particles upon insertion of the Pd2+ ions. The position and intensity in near-infrared LSPRs can be tuned by altering the thickness of the shell and are in agreement with the theoretical optical simulation based on the Mie-Gans theory and Drude model. Compared to the starting CuS NCs, the amorphous CuPd x S shell in the core-shell nanoparticles makes their plasmonic response less sensitive to a harsh oxidation environment (generated, for example, by the presence of I2).

Women's experiences of making healthcare decisions about their breast cancer: A phenomenological study.

There are few studies about how healthcare decisions are made for women with breast cancer in China and this knowledge is vital, both to further develop person-centered health care and to ensure that women have a voice in their healthcare decisions. This phenomenological study explored the meaning of women's lived experiences of making healthcare decisions about their breast cancer in China. Semistructured, in-depth interviews were conducted with a purposive sample of eight women with breast cancer. Data were analyzed using Colaizzi's phenomenological analytic method. The results of this study identified four themes: authority and expertise, lack of knowledge, family support, and Chinese cultural and social influences. Women were deferential to medical authority and perceived expertise, but they wanted to be involved to a greater degree in healthcare decisions. It is important for health professionals to optimize women's participation in decision-making by removing barriers and advocating on their behalf.

Epidemiological survey of childhood asthma in Kunming City, China / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the prevalence of childhood asthma, and to find the distribution characteristics, precipitating factors, diagnosis and treatment status, and to provide scientific data for improving the prevention and management of asthma in children in Kunming City, China.</p><p><b>METHODS</b>Children were selected by random cluster sampling. A standardized preliminary questionnaire was used for screening out possible patients in the survey. Diagnosis of asthma was confirmed by diagnostic criteria in suspected asthmatic children. Asthmatic children were further asked for past diagnosis and treatment with the questionnaire of asthma in children.</p><p><b>RESULTS</b>The total asthma incidence rate was 1.40%. The prevalence of asthma in male and female children was 1.89% and 0.88% respectively (P<0.05). Children aged 0-5 years old had a higher prevalence of asthma (1.69%) than that of school-age children (6-14 years old, 1.21%). In all asthmatic children, 51.3% were previously diagnosed with classical asthma or cough variant asthma, 26.0% were suffered attacks from December to February, and 54.0% were suffered attacks at midnight or dawn. Respiratory tract infection (87.3%) was the most common triggers of asthma exacerbation. Antibiotics were used in 80.0%, bronchodilators in 66.0%, inhaled corticosteroid in 64.0%. A peak flow meter for monitoring lung function was used in 17% of asthmatic children over 5 years old.</p><p><b>CONCLUSIONS</b>The prevalence of asthma is associated with age and gender in children aged 0-14 years old in Kunming City. Acute asthma attack occurs mostly in winter and at midnight or dawn. Respiratory tract infection is the most common trigger of asthma exacerbation. Nearly a half of patients with asthma had not been diagnosed with asthma in the early stage. Most asthmatic children use antibiotics and only two-thirds use bronchodilators or inhaled corticosteroid in the treatment. The treatment and management of asthma in children awaits improvement as well.</p>

Neurobehavioral function of neonatal mice following excitotoxic brain damage / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To assess the changes of neurobehavioral function in a neonatal mouse model of excitotoxic brain damage.</p><p><b>METHODS</b>Fifty-five 5-day-old ICR neonatal mice were randomly assigned to three groups: blank (no intravenous) control (n=20), saline control (n=20) and excitotoxic brain damage model (ibotenic acid treatment, n=15). Behavioral function was evaluated by the surface righting reflex test (postnatal days 6-10), the swimming test (postnatal days 8-12) and the Y-maze discrimination learning test (postnatal days 33-34).</p><p><b>RESULTS</b>Righting time in the surface righting reflex test in the ibotenic acid treatment group on postnatal days 6-10 was more prolonged than that in the two control groups (p<0.05). Swimming test scores in the ibotenic acid treatment group were significantly lower than those in the two control groups (p<0.05). In the Y-maze discrimination learning test, the mice from the ibotenic acid treatment group performed significantly worse than two control groups, presenting with increased learning times (19.79+/-2.42 vs 16.29+/-2.48 or 16.30+/-2.37; p<0.05) and achieving a lower correct percentage (86.7% vs 96.5% or 95.0%) (p<0.05).</p><p><b>CONCLUSIONS</b>The developmental reflexes and learning and memory functions were impaired in neonatal mice following excitotoxic brain damage. Behavioral testing is useful in the evaluation of early developmental reflexes and long-term neurobehavioral outcome in neonatal mice with excitotoxic brain damage.</p>

Survey on the epidemic characteristics of suicidal tendency among middle-school students in cities / 中华流行病学杂志

<p><b>OBJECTIVE</b>To identify the epidemical characteristics of suicidal tendency among middle-school students in cities of China and to explore the main factors leading to suicidal tendency in adolescents.</p><p><b>METHODS</b>Multi-stage cluster sampling method was used to select 9015 students in grades 1, 2, 3 and 4 respectively from 25 general middle schools in Beijing, Hangzhou, Wuhan and Urumqi of China in June 2006 and field investigation was carried out through "China Global School-based Student Health Survey (GSHS) Questionnaire".</p><p><b>RESULTS</b>Among the students in the four cities, the incidence rates of suicidal ideation were from 14.4% to 20.8% with an average of 17.4%. The incidence rates of suicidal plan were from 6.8% to 9.7% with an average of 8.2% and were different among cities. 15.0% of the boys had suicidal ideation and 6.7% of them made a suicidal plan comparing to 19.7% of girls having had suicidal ideation and 9.5% of them made a suicidal plan. The two kinds of suicidal tendency in girls were all higher than those in boys. City, age, gender, grade, days and type of being bullied, depression, close friends and having received health education on coping with stresses were factors influencing suicidal tendency of students. Days of being bullied and suicidal tendency showed a dose-response relation.</p><p><b>CONCLUSION</b>Suicidal tendency seemed common in middle-school students. Training on 'coping the issue' should be strengthened and harmonious environment should be improved in middle-schools.</p>