Twisting, untwisting, and retwisting of elastic Co-based nanohelices.

The reversible transformation of a nanohelix is one of the most exquisite and important phenomena in nature. However, nanomaterials usually fail to twist into helical crystals. Considering the irreversibility of the previously studied twisting forces, the reverse process (untwisting) is more difficult to achieve, let alone the retwisting of the untwisted crystalline nanohelices. Herein, we report a new reciprocal effect between molecular geometry and crystal structure which triggers a twisting-untwisting-retwisting cycle for tri-cobalt salicylate hydroxide hexahydrate. The twisting force stems from competition between the condensation reaction and stacking process, different from the previously reported twisting mechanisms. The resulting distinct nanohelices give rise to unusual structure elasticity, as reflected in the reversible change of crystal lattice parameters and the mutual transformation between the nanowires and nanohelices. This study proposes a fresh concept for designing reversible processes and brings a new perspective in crystallography.

A rapid, accurate, and low-cost method for detecting Mycobacterium tuberculosis and its drug-resistant genes in pulmonary tuberculosis: Applications of MassARRAY DNA mass spectrometry.

Introduction: Mycobacterium tuberculosis (MTB) identification and drug resistance diagnosis are very important for treatment of drug-resistant tuberculosis (DR-TB). Therefore, high throughput, accurate and low-cost molecular detection techniques are urgently needed. This study aimed to evaluate the clinical application value of MassARRAY in tuberculosis diagnosis and drug resistance screening. Methods: The limit of detection (LOD) and clinical application value of MassARRAY were evaluated using reference strains and clinical isolates. MTB in bronchoalveolar lavage fluid (BALF) and sputum samples were detected using MassARRAY, quantitative real-time polymerase chain reaction (qPCR) and MGIT960 liquid culture (culture). Using culture as the standard, the efficacy of MassARRAY and qPCR for the detection of TB was analyzed. Mutation of drug resistance genes in MTB clinical isolates was tested using MassARRAY, high-resolution melting curve (HRM), and Sanger sequencing. Using sequencing as the standard, the efficacy of MassARRAY, and HRM for the detection of each drug resistance site of MTB was analyzed. Simultaneously, the mutation of drug resistance genes by the MassARRAY method was compared with the results of drug susceptibility testing (DST), and the genotype-phenotype relationship was analyzed. The ability of MassARRAY to discriminate mixed infections was detected using mixtures of standard strains (M. tuberculosis H37Rv) and drug-resistant clinical isolates and mixtures of wild-type and mutant plasmids. Results: In MassARRAY, 20 related gene mutations could be detected by two PCR systems. All genes could be accurately detected when the bacterial load was 104 CFU/mL. When the load of wild-type and drug-resistant MTB mixture was 105 CFU/mL (respectively reached 104 CFU/mL), variants and wild-type genes could be detected simultaneously. The sensitivity of MassARRAY (96.9%) for identification was higher than that of qPCR (87.5%) (p < 0.001). The sensitivity and specificity of MassARRAY for all drug resistance gene mutations were 100.0%, with higher accuracy and consistency than HRM (sensitivity = 89.3% and specificity = 96.9%, p = 0.001). Analyzing the relationship between MassARRAY genotype and DST phenotype, the accuracy of katG_315, rpoB_531, rpsL_43, rpsL_88, and rrs_513 sites was 100.0%, and embB_306 and rpoB_526 were inconsistent with the DST results when the base changes were different. Discussion: MassARRAY can obtain base mutation information and identify heteroresistance infections simultaneously when the mutant proportion was at least 5-25%. It has good application prospects in the diagnosis of DR-TB with high throughput, accurate and low-cost.

Treatment Outcomes and Risk Factors of Multidrug-Resistant Tuberculosis Patients in Xi'an China, a Retrospective Cohort Study.

Background: Long-term regimens are widely used for multidrug-resistant tuberculosis (MDR-TB) in North-West China; however, risk factors associated with the treatment outcomes are not well known. Methods: This was a retrospective cohort study of MDR-TB patients treated with longer regimen in Xi'an from 2017 to 2019. Risk factors associated with the treatment outcome were analyzed using multiple logistic regression. Results: Of the 446 patients with MDR-TB included, 215 were cured, 84 completed treatment, 23 failed treatment, 108 were lost to follow-up, and 16 died. Unfavorable outcome risk factors were age >40 years (OR = 3.25, 95% CI = 2.12-4.98), male sex (OR = 2.53, 95% CI = 1.52-4.22), and re-treated tuberculosis (OR = 1.70, 95% CI = 1.11-2.61), whereas poor treatment outcome risk factors were age >40 years (OR = 5.51, 95% CI = 2.52-12.07), fluoroquinolones not used in the regimen (OR = 3.31, 95% CI = 1.45-7.51), and smear-positive (OR = 4.0, 95% CI = 1.47-10.8). Conclusion: In Xi'an, MDR-TB treatments with long-term regimens had low success rates, and age, sex, and tuberculosis treatment history were risk factors of MDR-TB treatment outcomes.

Recent Progress in Doped g-C3N4 Photocatalyst for Solar Water Splitting: A Review.

Graphitic carbon nitride (g-C3N4) photocatalysis for water splitting is harvested as a fascinating way for addressing the global energy crisis. At present, numerous research subjects have been achieved to design and develop g-C3N4 photocatalysis, and the photocatalytic system still suffers from low efficiency that is far from practical applications. Here, there is an inspiring review on the latest progress of the doping strategies to modify g-C3N4 for enhancing the efficiency of photocatalytic water splitting, including non-metal doping, metal doping, and molecular doping. Finally, the review concludes a summary and highlights some perspectives on the challenges and future research of g-C3N4 photocatalysts.

Identification of potential genes in endobronchial tuberculosis after bronchoscopic cryotherapy by transcriptome sequencing.

BACKGROUND: Bronchoscopic cryotherapy facilitates the treatment of endobronchial tuberculosis (EBTB) and helps suppress progressive bronchial stenosis. However, the molecular mechanism of bronchoscopic cryotherapy in EBTB patients has not been reported. METHODS: Transcriptome sequencing was performed to explore differentially expressed mRNAs (DEGs) in EBTB patients before and after bronchoscopic cryotherapy. Gene Ontology (GO) and KEGG analyses were carried out. Five genes (MKLN1, HIGD1A, PTGES, SKIL, and MCEMP1) were selected and validated using real-time qPCR (RT- qPCR). RESULTS: In transcriptome analysis, 448 DEGs with p < 0.05 and|logFC| > 1 were identified; of these, 171 and 277 DEGs were significantly up- and down-regulated after bronchoscopic cryotherapy, respectively. Results displayed 337 biological process (GO-BP), 48 cellular component (GO-CC) and 62 molecular function (GO-MF) terms and 20 KEGG pathways. RT- qPCR results were consistent with the sequencing data. CONCLUSION: These data provide informative evidence and recommendations for further scientific research on bronchoscopic cryotherapy for EBTB.

Sex differences in immune responses to SARS-CoV-2 in patients with COVID-19.

Millions of people infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been diagnosed with coronavirus infectious disease 2019 (COVID-19). The prevalence and severity of COVID-19 differ between sexes. To explain these differences, we analyzed clinical features and laboratory values in male and female COVID-19 patients. The present study included a cohort of 111 people, i.e. 36 COVID-19 patients, 54 sex- and age-matched common viral community-acquired pneumonia (CAP) patients, and 21 healthy controls. Monocyte counts, lymphocyte subset counts, and alanine aminotransferase (ALT), aspartate aminotransferase (AST), and C-reactive protein (CRP) levels in the peripheral blood were analyzed. Higher Acute Physiology and Chronic Health Evaluation II (APACHE II) scores, monocyte counts, and CRP and ALT levels were found in male COVID-19 patients. Decreased lymphocyte subset counts and proportions were observed in COVID-19 patients, except for the CD3+ and CD8+ T cell proportions. The lower CD4+ T cell proportions and higher CD8+ T cell proportions were observed in male and severe COVID-19 patients and the differences were independent of estrogen level. The CD4+ T cell proportion was negatively associated with the CD8+ T cell proportion in male COVID-19 patients; this correlation was non-significant in females. Our work demonstrates differences between sexes in circulating monocyte counts and CD4+ T cell and CD8+ T cell proportions in COVID-19 patients, independent of estrogen levels, are associated with the clinical manifestations in COVID-19 patients with high specificity.

A comparative study of the laboratory features of COVID-19 and other viral pneumonias in the recovery stage.

BACKGROUND: Clinical recovery does not mean full recovery. It is necessary to explore the aftereffects of COVID-19 in patients and compare the laboratory features of COVID-19 and other viral pneumonias in the recovery stages. METHODS: Forty-seven cases of COVID-19 and 45 cases of other viral pneumonias (control) were included in this study. The laboratory parameters were compared between COVID-19 and control patients as well as severe and moderate COVID-19 patients from the clinical recovery stage to the 4 weeks postdischarge recovery stage. RESULTS: A higher RDW-CV level and neutrophil percentage and lower levels of total proteins, lymphocytes, eosinophils, and MCH were found in COVID-19 patients compared with those in controls from the clinical recovery to the postdischarge recovery stages. Further analysis showed that decreases in lymphocytes, total proteins, and SOD and elevations in neutrophils, FDP, CRP, and ESR were more common in severe than moderate cases of COVID-19 during hospitalization; however, differences in these indicators, except total proteins, were not observed in the postdischarge recovery stages. Additionally, only 76.9% of COVID-19 patients were positive for IgG antibodies against SARS-CoV-2 in the convalescence stage, and one patient that was negative for specific IgG was reinfected. CONCLUSIONS: This study demonstrated that patients recovering from COVID-19 might need better care than that patients with other viral pneumonias due to the possibility of having poor immunity and nutritional conditions. These findings provide new insights to improve the understanding of COVID-19 and improve care for patients affected by these kinds of pandemics in the future.

Simple and sensitive method for the analysis of 14 antituberculosis drugs using liquid chromatography/tandem mass spectrometry in human plasma.

Monitoring plasma concentration and adjusting doses of antituberculosis (TB) drugs are beneficial for improving responses to drug treatment and avoiding adverse drug reactions. A simple and sensitive liquid chromatography/tandem mass spectrometry method was developed to measure the plasma concentrations of 14 anti-TB drugs: ethambutol, isoniazid, pyrazinamide, levofloxacin, gatifloxacin, moxifloxacin, prothionamide, linezolid, rifampin, rifapentine, rifabutin, cycloserine, p-aminosalicylic acid, and clofazimine. METHODS: Human plasma was precipitated by acetonitrile and was subsequently separated by an AQ-C18 column with a gradient elution. Drug concentrations were determined using multiple reaction monitoring in positive ion electrospray ionization mode. According to pharmacokinetic data of patients, the peak concentration ranges and the timing of blood collection were determined. RESULTS: Intra- and interday precision was < 14.8%. Linearity, accuracy, extraction recovery, and matrix effect were acceptable for each drug. The stability of the method satisfied different storage conditions. CONCLUSIONS: The method allowed the sensitive and reproducible determination of 14 frequently used anti-TB drugs which has already been of benefit for some TB patients.

Determinants of serum concentration of first-line anti-tuberculosis drugs from China.

Therapeutic drug monitoring has been employed in anti-tuberculosis (TB) drugs to assess optimal dose for maximum therapeutic effects and minimal toxicity. But the determinants of serum concentration need further evidences.In a retrospective case-control study, clinical and laboratory data were collected from 717 in-patients with TB at Xi'an Chest Hospital, China. Two hours serum concentrations of isoniazid, rifampicin, pyrazinamide as well as ethambutol were obtained and analyzed by liquid chromatography-tandem mass spectrometry.The month 2 culture conversion group had lower concentration of isoniazid, pyrazinamide, and ethambutol than month 1 group. Statistical analysis showed that serum concentrations of isoniazid, rifampicin, pyrazinamide, and ethambutol revealed a positive relationship with dose (mg/kg) (P < .001, P < .001, P < .001, and P = .003, respectively). Furthermore, isoniazid concentration was related to smoking (P = .009) and prior TB (P = .011), while rifampicin and pyrazinamide concentrations were correlated to sex (P = .004 and 0.025, respectively). Ethambutol concentration was associated with creatinine clearance (Ccr, P = .002).It is necessary to optimize drug doses using therapeutic drug monitoring while considering the following determinants: weight, smoking status, prior TB, sex, and Ccr. Furthermore, low 2 hours serum concentrations can be associated with longer culture conversion.

Tube-in-tube tin dioxide superstructures with enhanced lithium storage performance.

Novel tube-in-tube tin dioxide superstructures (TTS) were synthesized with α-Fe2O3 hollow prisms as templates. Due to the special tube-in-tube structure, the SnO2 TTS possess brilliant lithium storage properties.

GYY4137 Promotes Mice Feeding Behavior via Arcuate Nucleus Sulfur-Sulfhydrylation and AMPK Activation.

Hydrogen sulfide (H2S) is an endogenous gaseous molecule and plays important biological and neurochemical roles in many processes such as the neural activity and immunity. The arcuate nucleus (ARC) of hypothalamus is a control center for appetite and energy metabolism. AMPK is a gage kinase in the monitoring of energy status and regulation of energy metabolism, and it can be activated by H2S via CaMKKß/AMPK pathway. But the role of H2S in ARC and appetite has not been reported. Here we studied the orexigenic effect of H2S and the mechanisms by means of GYY4137, a water soluble and slow-releasing donor of H2S, and protein sulfur-sulfhydrylation analysis. We demonstrated that GYY4137-derived H2S increased food intake of mice, augmented the production of neuropeptide Y (NPY), and elevated the protein sulfur-sulfhydrylation level and the activation of AMPK and CaMKKß in ARC. Blocking sulfur-sulfhydrylation with DTT eliminated GYY4137-induced activation of AMPK and CaMKKß. DTT and preventing AMPK activation in ARC with Compound C and Ara-A could both attenuate the orexigenic effect of GYY4137. These findings suggest that H2S enhances appetite through protein sulfur-sulfhydrylation and the activation of AMPK and NPY function in ARC.

Generalized Low-Temperature Fabrication of Scalable Multi-Type Two-Dimensional Nanosheets with a Green Soft Template.

Two-dimensional nanosheets with high specific surface areas and fascinating physical and chemical properties have attracted tremendous interests because of their promising potentials in both fundamental research and practical applications. However, the problem of developing a universal strategy with a facile and cost-effective synthesis process for multi-type ultrathin 2 D nanostructures remains unresolved. Herein, we report a generalized low-temperature fabrication of scalable multi-type 2 D nanosheets including metal hydroxides (such as Ni(OH)2, Co(OH)2, Cd(OH)2, and Mg(OH)2), metal oxides (such as ZnO and Mn3O4), and layered mixed transition-metal hydroxides (Ni-Co LDH, Ni-Fe LDH, Co-Fe LDH, and Ni-Co-Fe layered ternary hydroxides) through the rational employment of a green soft-template. The synthesized crystalline inorganic nanosheets possess confined thickness, resulting in ultrahigh surface atom ratios and chemically reactive facets. Upon evaluation as electrode materials for pseudocapacitors, the Ni-Co LDH nanosheets exhibit a high specific capacitance of 1087 F g(-1) at a current density of 1 A g(-1), and excellent stability, with 103% retention after 500 cycles. This strategy is facile and scalable for the production of high-quality ultrathin crystalline inorganic nanosheets, with the possibility of extension to the preparation of other complex nanosheets.

[A study of the value of three molecular diagnostic techniques in the diagnosis of tuberculosis].

OBJECTIVE: To evaluate the diagnostic value of real-time fluorescent RNA isothermal amplification detection technology (simultaneous amplification and testing, SAT), Mycobacterium nucleic acid detection (PCR-fluorescence probe)method (TB-NTM-PCR) and Xpert MTB/RIF detection in the diagnosis of tuberculosis. METHODS: A total of 378 sputum specimens from pulmonary tuberculosis patients were collected between April to July 2014 in Xi'an Thoracic Tumor and Tuberculosis Hospital. The specimens were detected by 5 methods at the same time including acid-fast stain, SAT method, TB-NTM-PCR method, TB 960 rapid liquid culture and Xpert MTB/RIF. The sensitivity and specificity of SAT method, TB-NTM-PCR method and Xpert MTB/RIF were calculated according to the results of TB 960 rapid liquid culture and staining. The difference among all the 3 methods was analyzed by Chi-squared test. RESULTS: The positive rate of SAT-TB,TB-NTM-PCR and Xpert MTB/RIF were 37.6% (142/378), 37.8% (143/378) and 53.4% (202/378), respectively. In specimens both positive for acid-fast stain and culture, the positive rate of SAT method was 84.6% (77/91), that of TB-NTM-PCR was 91.2% (83/91), and that of Xpert MTB/RIF was 96.7% (88/91), the difference being significant (P=0.018 2). In specimens negative for acid-fast stain but positive for culture, the positive rate of SAT method was 61.9% (60 /97), that of TB-NTM-PCR was 44.3% (43/97), and that of Xpert MTB/RIF was 80.4% (78/97), the difference being significant (P<0.000 1). In specimens both negative for acid-fast stain and culture, the positive rate of SAT method was 1.6% (3/185), that of TB-NTM-PCR was 6.5% (12/185), and that of Xpert MTB/RIF was 16.8% (31/185), the difference being significant (P=0.018). In specimens positive for acid-fast stain but negative for culture, the number of positive samples of SAT,TB-NTM-PCR and Xpert MTB/RIF were 3 (3/5), 5 (5/5),and 5 (5/5), respectively. With the result of TB 960 rapid liquid culture and staining as the reference, Xpert MTB/RIF showed the highest sensitivity of 87.6% (163/186), the minimum rate of missed diagnosis of 12.4% (24/193), and the highest negative predictive value of 88.5% (185/209); SAT-TB showed the highest specificity of 98.2% (214/218), the minimum rate of misdiagnosis of 1.8%(4/218), the highest positive predictive value of 97.2% (138/142). With the result of TB 960 rapid liquid culture as the reference, the sensitivity and the specificity of Xpert MTB/RIF were 95.52% (128/134) and 95.24% (20/21). The accordance rate of Xpert MTB/RIF and TB 960 rapid liquid culture was 95.48%(148/155). CONCLUSION: The 3 molecular detection methods showed good results for the auxiliary diagnosis of tuberculosis. Xpert MTB/RIF had the best performance both in smear positive and negative specimens and it can detect rifampicin related rpoB gene mutations at the same time.

Bottom-up-then-up-down Route for Multi-level Construction of Hierarchical Bi2S3 Superstructures with Magnetism Alteration.

A bottom-up-then-up-down route was proposed to construct multi-level Bi2S3 hierarchical architectures assembled by two-dimensional (2D) Bi2S3 sheet-like networks. BiOCOOH hollow spheres and flower-like structures, which are both assembled by 2D BiOCOOH nanosheets, were prepared first by a "bottom-up" route through a "quasi-emulsion" mechanism. Then the BiOCOOH hierarchical structures were transferred to hierarchical Bi2S3 architectures through an "up-down" route by an ion exchange method. The obtained Bi2S3 nanostructures remain hollow-spherical and flower-like structures of the precursors but the constructing blocks are changed to 2D sheet-like networks interweaving by Bi2S3 nanowires. The close matching of crystal lattices between Bi2S3 and BiOCOOH was believed to be the key reason for the topotactic transformation from BiOCOOH nanosheets to 2D Bi2S3 sheet-like nanowire networks. Magnetism studies reveal that unlike diamagnetism of comparative Bi2S3 nanostructures, the obtained multi-level Bi2S3 structures display S-type hysteresis and ferromagnetism at low field which might result from ordered structure of 2D networks.

Three-dimensional honeycomb-like networks of birnessite manganese oxide assembled by ultrathin two-dimensional nanosheets with enhanced Li-ion battery performances.

Three-dimensional (3D) honeycomb-like birnessite networks composed of ultrathin two-dimensional (2D) nanosheets were firstly synthesized through a facile and low-cost synthetic route. By using carbon microspheres as a template instead of graphene, hierarchical birnessite structures assembled by ultrathin nanosheets including york-shell and hollow structures were obtained besides the ultrathin birnessite nanosheets with a thickness of about 0.7 nm. By assembling carbon spheres into an ordered 3D array, novel 3D honeycomb-like birnessite structures assembled by ultrathin nanosheets were firstly prepared. When evaluated as an anode material for Li-ion batteries, the 3D honeycomb-like networks show enhanced electrochemical performances with high capacities, excellent cycling stability and good rate capability, which can be ascribed to the novel 3D honeycomb-like macroporous structure with a 3D inverse opal structure, well-ordered macropores, interconnected walls and a regular periodicity.