Epidemiological and clinical features of COVID-19 inpatients in Changsha, China: A retrospective study from 2020 to 2022.

Objectives: The spread of SARS-Cov-2 remains a global concern along with the emergence of variants. This study aims to characterize the epidemiological and clinical features of hospitalized patients who were dragonized with five different variants of SARS-CoV-2 during the past 3 years. Methods: This retrospective study recruited 432 COVID-19 patients who were hospitalized in the First Hospital of Changsha from January 2020 to August 2022. Clinical records on clinical symptoms, laboratory profiles, and chest CT images was collected. The epidemiological and clinical features were compared between COVID-19 patients infected with either the wild-type, Omicron variant or pre- Omicron variants (e.g., Alpha, Beta, Delta). Results: A total of 432 laboratory-confirmed COVID-19 inpatients were dialogized during three waves, including 247 cases during the wild-type transmission period, 65 cases during the transmission period of pre-Omicron variants, and 119 cases during the transmission period of Omicron variants. The proportion of moderately or severely ill inpatients showed a gradual decline from the wild-type transmission period to the Omicron transmission period. The common symptoms of inpatients infected with SARS-CoV-2 wildtype strains included fever (67.61 %), cough (57.89 %), fatigue (33.60 %), and shortness of breath (12.15 %). In contrast, patients infected with other variants mostly showed upper respiratory symptoms. Based on chest CT images, a lower degree of acute pulmonary infection was observed among inpatients infected with the Omicron variants than those infected with the wild-type strain (31.09 % vs 93.12 %, p-value<0.01). Conclusions: Compared with the wild-type strain, SARS-CoV-2 variants of concern, especially the Omicron variant, mostly caused a lower degree of acute pulmonary infection, indicating the reduced disease severity and mortality among hospitalized COVID-19 patients.

P38-DAPK1 axis regulated LC3-associated phagocytosis (LAP) of microglia in an in vitro subarachnoid hemorrhage model.

BACKGROUND: The phagocytosis and homeostasis of microglia play an important role in promoting blood clearance and improving prognosis after subarachnoid hemorrhage (SAH). LC3-assocaited phagocytosis (LAP) contributes to the microglial phagocytosis and homeostasis via autophagy-related components. With RNA-seq sequencing, we found potential signal pathways and genes which were important for the LAP of microglia. METHODS: We used an in vitro model of oxyhemoglobin exposure as SAH model in the study. RNA-seq sequencing was performed to seek critical signal pathways and genes in regulating LAP. Bioparticles were used to access the phagocytic ability of microglia. Western blot (WB), immunoprecipitation, quantitative polymerase chain reaction (qPCR) and immunofluorescence were performed to detect the expression change of LAP-related components and investigate the potential mechanisms. RESULTS: In vitro SAH model, there were increased inflammation and decreased phagocytosis in microglia. At the same time, we found that the LAP of microglia was inhibited in all stages. RNA-seq sequencing revealed the importance of P38 MAPK signal pathway and DAPK1 in regulating microglial LAP. P38 was found to regulate the expression of DAPK1, and P38-DAPK1 axis was identified to regulate the LAP and homeostasis of microglia after SAH. Finally, we found that P38-DAPK1 axis regulated expression of BECN1, which indicated the potential mechanism of P38-DAPK1 axis regulating microglial LAP. CONCLUSION: P38-DAPK1 axis regulated the LAP of microglia via BECN1, affecting the phagocytosis and homeostasis of microglia in vitro SAH model. Video Abstract.

In situ prepared Chlorella vulgaris-supported nanoscale zero-valent iron to remove arsenic (III).

Nanoscale zero-valent iron (nZVI) has a high removal affinity toward arsenic (As). However, the agglomeration of nZVI reduces the removal efficiency of As and, thus, limit its application. In this study, we report an environmentally friendly novel composite of Chlorella vulgaris-supported nanoscale zero-valent iron (abbreviated as CV-nZVI) that exhibits a fast and efficient removal of As(III) from As-contaminated water. Scanning electron microscopy-energy-dispersive spectroscopy (SEM-EDS), X-ray diffractometry (XRD), attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), and X-ray photoelectron spectroscopy (XPS) were used to characterize and analyze the CV-nZVI. These results indicated that the stabilization effect of C. vulgaris reduced the nZVI agglomeration and enhanced the reactivity of nZVI. The experiments showed a removal efficiency of 99.11% for As(III) at an optimum pH of 7.0. The adsorption kinetics and isotherms followed the pseudo-second-order kinetic model and Langmuir adsorption isotherm with the superior maximum adsorption capacities of 34.11 mg/g for As(III). The FTIR showed that the As(III) was adsorbed on the CV-nZVI surface by complexation reaction, and XPS indicated that oxidation reaction was also involved. After five reuse cycles, the removal efficiency of As(III) by CV-nZVI was 32.93%, suggesting that the CV-nZVI had some reusability and regeneration. Overall, this work provides a practical and highly efficient approach for As remediation in As-contaminated water, and simultaneously resolves the agglomeration problems of nZVI nanoparticles.

Salidroside alleviates oxidative stress in dry eye disease by activating autophagy through AMPK-Sirt1 pathway.

Dry eye disease (DED) is a multifactorial disease, and oxidative stress plays a crucial role in its pathogenesis. Recently, multiple studies have shown that upregulation of autophagy can protect the cornea from oxidative stress damage. The present study investigated the therapeutic effects of salidroside, the main component of Rhodiola crenulata, in both in vivo and in vitro dry eye models. The results showed that topical eye drop treatment with salidroside restored corneal epithelium damage, increased tear secretion, and reduced cornea inflammation in the DED mice. Salidroside activated autophagy through AMP-activated protein kinase (AMPK)-sirtuin-1 (Sirt1) signaling pathway, which promoted the nuclear translocation of nuclear factor erythroid-2-related factor 2 (Nrf2) and increased the expression of downstream antioxidant factors heme oxygenase-1 (HO-1) and NAD(P)H quinone dehydrogenase 1 (NQO1). This process restored antioxidant enzyme activity, reduced reactive oxygen species (ROS) accumulation, and alleviated oxidative stress. The application of autophagy inhibitor chloroquine and AMPK inhibitor Compound C reversed the therapeutic efficacy of salidroside, validating the above findings. In conclusion, our data suggest that salidroside is a promising candidate for DED treatment.

Poor glycemic control in type-2 diabetic patients infected with hepatitis B: A retrospective propensity-matched study.

Hepatitis B virus (HBV) infection and type-2 diabetes mellitus (T2DM) affect millions of individuals worldwide, whereas their interplay remains largely unclear. Here, we analyzed a large cohort of 330 HBV-infected inpatients with T2DM (so-called HBV + T2DM patients) and 330 T2DM inpatients without HBV infection (T2DM patients). Poor glycemic control was defined by glycated hemoglobin (HbA1c) ≥ 7%. Among 330 HBV + T2DM patients, 252 (76%) aged ≥ 50 years, 223 (68%) were males, 205 (62%) experienced poor glycemic control. The propensity-score matching approach was applied to match patient age, gender, comorbidities, and antidiabetic treatment between T2DM + HBV and T2DM patients. Compared with T2DM patients, HBV + T2DM patients had poorer glycemic control, longer hospitalization length, and higher alanine aminotransferase (p < 0.05). HBV + T2DM patients with HBV DNA ≥ 100 IU/mL or HBsAg ≥ 0.05 IU/mL had worse HbA1c control than T2DM patients without HBV infection (p < 0.05). HBV + T2DM patients who received no anti-HBV therapy had worse HbA1c control than HBV + T2DM patients receiving anti-HBV therapy (p < 0.05). Both insulin and anti-HBV therapy were significant factors associated with glycemic control in HBV + T2DM patients. Overall, HBV + T2DM patients exhibited poorer glycemic control than T2DM patients, but their clinical outcomes were likely improved by insulin plus anti-HBV treatment. Early management of HBV infection likely contributes to better clinical outcomes in HBV-infected patients with T2DM.

Comparative effectiveness of oseltamivir versus peramivir for hospitalized children (aged 0-5 years) with influenza infection.

OBJECTIVES: The effectiveness of oseltamivir versus peramivir in children infected with influenza remains unclear. This study aimed to evaluate their effectiveness in young children (aged 0-5 years) infected with severe influenza A virus (IAV) or influenza B virus (IBV). METHODS: We analyzed a cohort of 1662 young children with either IAV (N = 1095) or IBV (N = 567) who received oseltamivir or peramivir treatment from January 1, 2018 to March 31, 2022. Propensity score matching methods were applied to match children who were oseltamivir-treated versus peramivir-treated. RESULTS: Children who were IAV-infected and IBV-infected shared similar features, such as influenza-associated symptoms and comorbidities at baseline. Among children infected with IAV with bacterial coinfection, the recovery rate was significantly greater in children treated with oseltamivir than in children treated with peramivir (15.6% vs 4.4%, P = 0.01). The median duration of hospitalization was also shorter in children treated with oseltamivir. Among children infected with IAV without bacterial coinfection, the recovery rate was greater in children treated with oseltamivir than in children treated with peramivir (21.1% vs 3.7%, P = 0.002). However, oseltamivir and peramivir offered similar recovery rates and duration of hospitalization (P >0.05 for both) among children infected with IBV. CONCLUSION: Oseltamivir and peramivir exhibit similar effectiveness in young children with severe influenza B, whereas oseltamivir demonstrated improved recovery and shorter hospitalization in the treatment of severe influenza A in hospitalized children.

Hemoglobin Derived from Subarachnoid Hemorrhage-Induced Pyroptosis of Neural Stem Cells via ROS/NLRP3/GSDMD Pathway.

Accumulating evidence has demonstrated that neural stem cells (NSCs) have regenerative capacity after brain injuries, such as in aneurysmal subarachnoid hemorrhage (SAH). The reactive oxygen species (ROS)-induced NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome triggers inflammatory responses and pyroptosis of cells; however, whether ROS-induced neuroinflammation modulates the fate of endogenous NSCs after SAH remains largely unknown. In this study, the level of IL-1ß was increased in the cerebrospinal fluid (CSF) of patients with SAH. In an endovascular perforation model of SAH in mice, the secretion of IL-1ß increased to a peak at 24 h following SAH, and the expression of Caspase1 and NLRP3 was elevated in the hippocampus. Primary cultured NSCs were incubated with hemoglobin (Hb) to mimic SAH in vitro. The cell viability, LDH release, intracellular ROS levels, scanning electron microscopy (SEM), and the expression of NLRP3 and pyroptosis indicators (GSDMD, ASC, and Caspase-1) in NSCs after SAH were examined to investigate the process of pyroptosis. We found that pyroptotic death featuring cellular swelling, cell membrane pore formation and elevated IL-1ß was increased in cultured primary NSCs after Hb treatment, as was the expression of NLRP3, ASC, Caspase-1, and GSDMD. In addition, we found that ROS-induced pyroptosis of NSCs by activating the NLRP3/GSDMD pathway. These findings suggest that pyroptosis of NSCs induced by Hb can impede neural regeneration after SAH.

Immune repertoire sequencing reveals an abnormal adaptive immune system in COVID-19 survivors.

Accumulating evidence suggests that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) impairs the adaptive immune system during acute infection. Still, it remains largely unclear whether the frequency and functions of T and B cells return to normal after the recovery of Coronavirus Disease 2019 (COVID-19). Here, we analyzed immune repertoires and SARS-CoV-2-specific neutralization antibodies in a prospective cohort of 40 COVID-19 survivors with a 6-month follow-up after hospital discharge. Immune repertoire sequencing revealed abnormal T- and B-cell expression and function with large T cell receptor/B cell receptor clones, decreased diversity, abnormal class-switch recombination, and somatic hypermutation. A decreased number of B cells but an increased proportion of CD19+ CD138+ B cells were found in COVID-19 survivors. The proportion of CD4+ T cells, especially circulating follicular helper T (cTfh) cells, was increased, whereas the frequency of CD3+ CD4- T cells was decreased. SARS-CoV-2-specific neutralization IgG and IgM antibodies were identified in all survivors, especially those recorded with severe COVID-19 who showed a higher inhibition rate of neutralization antibodies. All severe cases complained of more than one COVID-19 sequelae after 6 months of recovery. Overall, our findings indicate that SARS-CoV-2-specific antibodies remain detectable even after 6 months of recovery. Because of their abnormal adaptive immune system with a low number of CD3+ CD4- T cells and high susceptibility to infections, COVID-19 patients might need more time and medical care to fully recover from immune abnormalities and tissue damage.

Proposed risk-scoring model for estimating the prognostic impact of 1q gain in patients with newly diagnosed multiple myeloma.

1q gain (+1q) is the most common high-risk cytogenetic abnormality (HRCA) in patients with multiple myeloma (MM). However, its prognostic value remains unclear in the era of novel agents. Here, we retrospectively analyzed the impact of +1q on the outcomes of 934 patients newly diagnosed with MM. +1q was identified in 53.1% of patients and verified as an independent variate for inferior overall survival (OS) (hazard ratio, 1.400; 95% confidence interval, 1.097-1.787; p = .007). Concurrence of other HRCAs (particularly t(14;16) and del(17p)) further exacerbated the outcomes of patients with +1q, suggesting prognostic heterogeneity. Thus, a risk-scoring algorithm based on four risk variates (t(14;16), hypercalcemia, ISS III, and high LDH) was developed to estimate the outcomes of patients with +1q. Of the patients, 376 evaluable patients with +1q were re-stratified into low (31.6%), intermediate (61.7%), and high risk (6.7%) groups, with significantly different progression-free survival and OS (p < .0001), in association with early relapse of the disease. The prognostic value of this model was validated in the CoMMpass cohort. While attaining undetectable MRD largely circumvented the adverse impact of +1q, it scarcely ameliorated the outcome of the patients with high risk, who likely represent a subset of patients with extremely poor survival. Hence, patients with +1q are a heterogeneous group of high-risk patients, therefore underlining the necessity for their re-stratification. The proposed simple risk-scoring model can estimate the outcomes of patients with +1q, which may help guide risk-adapted treatment for such patients.

Gender disparity and temporal trend of liver cancer in China from 1990 to 2019 and predictions in a 25-year period.

Objective: This study aims to reveal epidemiological features and trends of liver cancer (LC) in China. Methods: We retrieved data from the Global Burden of Disease database 2019. Joinpoint regression was used to examine the temporal trend of LC. Future trends of LC were estimated using the Nordpred. Results: The incidence, mortality, and disability-standardized life year (DALY) rate of LC declined in China from 1990 to 2019. Among >210,000 LC cases in 2019, the LC incidences were nearly 3.15 times higher in males than in females. LC cases and LC-associated deaths were mostly found among patients aged 65 to 69 years. The proportion of LC attributable to hepatitis B decreased over time, whereas the proportions of LC attributable to hepatitis C, alcohol use, and non-alcoholic steatohepatitis increased modestly from 1990 to 2019. The majority of LC-associated deaths could be traced to four risk factors: smoking (20%), drug use (13.6%), alcohol use (11.7%), and high body mass index (10.1%). Based on the Nordpred prediction, there will be a steady decline in the incidence (39.0%) and mortality (38.3%) of liver cancer over a 25-year period from 2020 to 2044. Conclusion: The disease burden of liver cancer in China has declined over the past 30 years. However, it remains important to control liver cancer among high-risk populations, especially elderly males with obesity, alcohol use, tobacco use, and/or drug abuse.

Revealing the Real Role of Etching during Controlled Assembly of Nanocrystals Applied to Electrochemical Reduction of CO2.

In recent years, the use of inexpensive and efficient catalysts for the electrocatalytic CO2 reduction reaction (CO2RR) to regulate syngas ratios has become a hot research topic. Here, a series of nitrogen-doped iron carbide catalysts loaded onto reduced graphene oxide (N-Fe3C/rGO-H) were prepared by pyrolysis of iron oleate, etching, and nitrogen-doped carbonization. The main products of the N-Fe3C/rGO-H electrocatalytic reduction of CO2 are CO and H2, when tested in a 0.5 M KHCO3 electrolyte at room temperature and pressure. In the prepared catalysts, the high selectivity (the Faraday efficiency of CO was 40.8%, at -0.3 V), and the total current density reaches ~29.1 mA/cm2 at -1.0 V as demonstrated when the mass ratio of Fe3O4 NPs to rGO was equal to 100, the nitrogen doping temperature was 800 °C and the ratio of syngas during the reduction process was controlled by the applied potential (-0.2~-1.0 V) in the range of 1 to 20. This study provides an opportunity to develop nonprecious metals for the electrocatalytic CO2 reduction reaction preparation of synthesis and gas provides a good reference.

Global Burden of Nutritional Deficiencies among Children under 5 Years of Age from 2010 to 2019.

Under-five years of age is a critical period for children's growth and development. Nutritional deficiency during this period is associated with wasting, underweight and stunting. We aimed to conduct an epidemiological study using data derived from the GBD2019 to found the global distribution and changing trends of nutritional deficiencies among children under 5 years old, as well as the correlation between social development status and nutritional deficiencies. Nutritional deficiencies in children under 5 years has been substantially improved in the past decade; however, the progress has been unevenly distributed globally. The incidence and DALY rate decreased with the increase of socio-demographic index. In 2019, the incidence (51,872.0 per 100,000) was highest in Central Sub-Saharan Africa and the DALY rate (5597.1 per 100,000) was the highest in Western Sub-Saharan Africa. Among five subcategories of nutritional deficiencies in children under 5 years, vitamin A deficiency accounted for the largest proportion of incident cases (100,511,850, 62.1% in 2019), while the proportion of DALYs caused by protein-energy malnutrition was the highest (9,925,276, 62.0%). Nutritional deficiency in some countries remains worrisome, for whom policies guarantees and sustained efforts to control nutritional deficiencies are urgently needed.

Epidemiology and Clinical Outcomes of HIV Infection in South-Central China: A Retrospective Study From 2003 to 2018.

Objective: HIV epidemiology in South-Central China is rarely reported. This study aims to characterize epidemiological and clinical features of HIV-infected patients in Hunan Province, located in South-Central China, for better management of HIV infections. Methods: This retrospective study retrieved multi-center records of laboratory-confirmed HIV-infected patients in Hunan province. Information on HIV-associated mortality and antiretroviral therapies was also collected. Results: Among 34,297 patients diagnosed with HIV infections from 2003 to 2018, 73.9% were males, 41.3% were older adults (≥50 years), and 71.2% were infected by heterosexual transmission. Despite a slow growth of new HIV infections in the overall population, annual percentages of HIV infections increased in older males (85.3% through heterosexual transmission) and young patients <30 years (39.9% through homosexual transmission). At baseline, serum levels of CD4+ T-cell counts were lower in older adults (191.0 cells/µl) than in young patients (294.6 cells/µl, p-value < 0.0001). A large proportion (47.2%, N = 16,165) of HIV-infected patients had advanced HIV disease (CD4+ T-cell counts < 200 cells/µl) from 2003 to 2018. All-cause mortality (57.0% due to AIDS-related illnesses) was reported among 4411 HIV-infected patients, including 2619 older adults. The 10-year survival rate was significantly lower in elderly males than in other patients (59.0 vs. 78.4%, p-value < 0.05). Conclusions: Elderly males are prone to HIV infections with a high risk of HIV-associated fatality. Our findings support early prevention and critical care for elderly populations to control HIV infections.

Trends in the disease burden of HBV and HCV infection in China from 1990-2019.

OBJECTIVES: This study aimed to reveal the 30-year dynamics of hepatitis B virus (HBV) and hepatitis C virus (HCV) disease burden in China from 1990-2019. METHODS: HBV/HCV data were retrieved from the Global Burden of Disease database. Joinpoint regression was used to examine temporal trends. Age-period-cohort models were applied to evaluate effects of patient age, period, and cohort on HBV/HCV-associated mortality and incidences. RESULTS: A dramatic decrease in the disease burden of HBV was found from 1990-2019, but the disease burden of HCV has remained stable since 2000. Patient age, period, and cohort exerted a significant effect on the diseases burden of HBV and HCV infection. Compared with women, men had a higher risk of HBV/HCV infections as well as HBV/HCV-associated mortality and liver cancer. Overweight, alcohol, tobacco, and drug use were important risk factors associated with HBV/HCV-associated liver cancer. The incidences of HBV- and HCV-associated liver cancer from 2019-2044 are expected to decrease by 39.4% and 33.3%, respectively. CONCLUSION: The disease burden of HBV/HCV infection has decreased in China over the past 30 years, but HBV incidences remain high, especially in men. Effective management of HBV and HCV infections is still needed for high-risk populations.

Association between inflammatory cytokines and anti-SARS-CoV-2 antibodies in hospitalized patients with COVID-19.

BACKGROUND: COVID-19 patients may experience "cytokine storm" when human immune system produces excessive cytokines/chemokines. However, it remains unclear whether early responses of inflammatory cytokines would lead to high or low titers of anti-SARS-CoV-2 antibodies. METHODS: This retrospective study enrolled a cohort of 272 hospitalized patients with laboratory-confirmed SARS-CoV-2. Laboratory assessments of serum cytokines (IL-2R, IL-6, IL-8, IL-10, TNF-α), anti-SARS-CoV-2 IgG/IgM antibodies, and peripheral blood biomarkers were conducted during hospitalization. RESULTS: At hospital admission, 36.4% patients were severely ill, 51.5% patients were ≥ 65 years, and 60.3% patients had comorbidities. Higher levels of IL-2R and IL-6 were observed in older patients (≥65 years). Significant differences of IL-2R (week 2 to week ≥5 from symptom onset), IL-6 (week 1 to week ≥5), IL-8 (week 2 to week ≥5), and IL-10 (week 1 to week 3) were observed between moderately-ill and severely ill patients. Anti-SARS-CoV-2 IgG titers were significantly higher in severely ill patients than in moderately ill patients, but such difference was not observed for IgM. High titers of early-stage IL-6, IL-8, and TNF-α (≤2 weeks after symptom onset) were positively correlated with high titers of late-stage IgG (≥5 weeks after symptom onset). Deaths were mostly observed in severely ill older patients (45.9%). Survival analyses revealed risk factors of patient age, baseline COVID-19 severity, and baseline IL-6 that affected survival time, especially in severely ill older patients. CONCLUSION: Early responses of elevated cytokines such as IL-6 reflect the active immune responses, leading to high titers of IgG antibodies against COVID-19.

PDK4 Decrease Neuronal Apoptosis via Inhibiting ROS-ASK1/P38 Pathway in Early Brain Injury After Subarachnoid Hemorrhage.

Aims: Metabolic disorders may play key roles in oxidative stress and neuronal apoptosis in response to early brain injury (EBI) after subarachnoid hemorrhage (SAH). Pyruvate dehydrogenase (PDH) is related to oxidative stress in EBI, and its activity obviously decreases after SAH. We discovered that only pyruvate dehydrogenase kinase 4 (PDK4) expression was obviously increased among the four PDK isozymes after SAH in preliminary experiments. Therefore, we attempted to investigate the effects and corresponding mechanisms of PDK4 on oxidative stress after SAH. Results: First, we confirmed that PDK4 overexpression promoted PDH phosphorylation, inhibited PDH activity, and changed cell metabolism after SAH. A small interfering RNA (siRNA) targeting PDK4, a lentiviral PDK4 overexpression vector, and dichloroacetic acid (DCA) were used to regulate the expression and activity of PDK4. The siRNA decreased PDH phosphorylation, promoted reactive oxygen species (ROS) production, activated the apoptosis signal-regulating kinase 1 (ASK1)/P38 pathway, and induced neuronal apoptosis. The lentivirus further attenuated PDH activity, oxidative stress, and neuronal apoptosis. DCA inhibited the activity of PDK4, but increased the expression of PDK4 due to a feedback mechanism. Inactivated PDK4 did not effectively suppress PDH activity, which increased ROS production, activated the ASK1/P38 pathway, and led to neuronal apoptosis. Innovation: This study provides new insights into the potential antioxidant and antiapoptotic effects of the PDK4-PDH axis on EBI after SAH. Conclusions: The early overexpression of PDK4 after SAH may attenuate neuronal apoptosis by reducing oxidative stress via the ROS/ASK1/P38 pathway. PDK4 may be a new potential therapeutic target to ameliorate EBI after SAH. Antioxid. Redox Signal. 36, 505-524.

A magnified aptamer fluorescence sensor based on the metal organic frameworks adsorbed DNA with enzyme catalysis amplification for ultra-sensitive determination of ATP and its logic gate operation.

With the development of frame materials, metal organic frameworks (MOFs) have been successfully applied in the fields of biological small molecule analysis and fluorescent DNA detection. In this work, in view of the good adsorption characteristics of MIL-101(Cr), the highly sensitive detection of adenosine triphosphate (ATP) assisted nucleic acid exonuclease amplification by MIL-101(Cr) on the different affinity of single stranded DNA and double stranded DNA was investigated. The detection limit of ATP reaches 1.7 µM, and the platform has good applicability in biological samples. On this basis, an "AND" logic gate was successfully constructed. Superior sensitivity to ATP in the presence of exonuclease was reflected, which greatly enhanced the system's fluorescence. Importantly, the fluorescence sensing application of this nanomaterial inspired other target detection and enriched the building blocks of fluorescence sensing platform.

Controlled assembly of nitrogen-doped iron carbide nanoparticles on reduced graphene oxide for electrochemical reduction of carbon dioxide to syngas.

The electrocatalytic CO2 reduction reaction (CO2RR) decreases the amount of greenhouse gas in the atmosphere while enabling a closed carbon cycle. Herein, iron oleate was used as a precursor to produce oleic acid-coated triiron tetraoxide nanoparticles (Fe3O4@OA NPs) by pyrolysis, which was then assembled with reduced graphene oxide (rGO) and doped with dicyandiamide as a nitrogen source to obtain nitrogen-doped iron carbide nanoparticles assembled on rGO (N-Fe3C/rGO NPs). The catalyst prepared by nitrogen doping at 800 °C with an Fe3O4@OA NPs to rGO weight ratio of 20:1 showed good activity and stability for the CO2RR. At -0.3 to -0.4 V, the H2/CO ratio of the product from the catalyzed CO2RR was close to 2; thus, the product can be used for Fischer-Tropsch synthesis. The results of a series of experiments and X-ray photoelectron spectroscopy analysis showed that the synergy between the CN and FeN groups in the catalyst can promote the reduction of CO2 to CO. This work demonstrates a facile method for improving the catalytic reduction of CO2.