Effectiveness of the enterovirus A71 vaccine on hand, foot and mouth disease: a real-world study in China.

OBJECTIVES: For the prevention of hand, foot and mouth disease (HFMD), enterovirus A71 (EV-A71) vaccines have been utilized in China since 2016. To better inform vaccination strategies, we assess the real-world effectiveness of EV-A71 vaccination in China. METHODS: The analysis was based on surveillance data of HFMD caused by EV-A71 in children under the age of five in China, along with meteorological and demographic data. The seasonal autoregressive integrated moving average model and the interrupted time-series analysis were used to estimate the effectiveness of the EV-A71 vaccination on the EV-A71 HFMD incidence and to predict the counterfactual cases with no EV-A71 vaccine. RESULTS: Between 2010 and 2018, 6,712,613 cases of HFMD caused by EV-A71 were reported in children under five years old in 260 Chinese cities. During 2017-2018, the EV-A71 vaccination was associated with a reduction in EV-A71 HFMD incidence, with a relative risk of 0.83 (95% confidence interval (CI): 0.81-0.86), and an estimated reduction of 297,946 (95% CI: 250,534-346,658) cases. However, this association varied across cities (I2=85.6%, P<0.001) and the effectiveness of EV-A71 vaccination decreased as population density increased. Higher vaccination coverage was associated with greater effectiveness of the EV-A71 vaccination and an earlier point in EV-A71 cases reduction. Specifically, when the vaccination coverage exceeded approximately 20%, the relative risk was rapidly reduced to below 0.71 (95% CI: 0.69-0.72). CONCLUSIONS: Our study demonstrated that the EV-A71 vaccination was associated with a reduction in the incidence of EV-A71 HFMD, but the association varied with regions and was influenced by vaccination coverage and population density. To optimize EV-A71 HFMD prevention, increasing vaccination coverage (over 20%) is recommended for children under five years old.

Inequalities in disease burden and care quality of chronic obstructive pulmonary disease, 1990-2021: Findings from the Global Burden of Disease Study 2021.

Background: Chronic obstructive pulmonary disease (COPD) is one of the primary causes of significant morbidity and mortality worldwide. This study aimed to explore the cross-country inequalities by age, sex, and region in COPD's burden and care quality from 1990 to 2021. Methods: We obtained data from the Global Burden of Disease 2021. Using age-standardised disability-adjusted life years rate (ASDR) per 100 000 population and quality of care index (QCI), we quantified the COPD burden and care quality, respectively. Applying the principal component analysis method, we calculated QCI scores, ranging from 0 to 100, where higher values indicate better care quality. We quantified temporal trends from 1990 to 2021 for ASDR and QCI by estimated annual percentage change (EAPC). Finally, we assessed the absolute and relative disparities in ASDR and QCI across countries using the slope index of inequality (SII) and concentration index. Results: Between 1990 and 2021, there was a notable decline in ASDR of COPD globally (1990 = 1492.64; 2021 = 940.66; EAPC = -1.71), accompanied by an increase in QCI (1990 = 58.42; 2021 = 73.86; EAPC = 0.89). Regions with middle sociodemographic index (SDI) consistently demonstrated the highest ASDR and the lowest QCI in 1990 (ASDR = 2332.91; QCI = 31.70), whereas by 2021, low-middle SDI regions exhibited similar trends (ASDR = 1707.90; QCI = 57.50). In 2021, the highest ASDR was among individuals aged 95 years and above (16251.22), while the lowest QCI was among people aged 70-74 years (72.18). Papua New Guinea recorded the highest ASDR and the lowest QCI in 2021 (ASDR = 3004.36; QCI = 19.18). Compared to 1990, where the SII for ASDR was -612.44 and for QCI was 21.78, with concentration indices of -0.14 for ASDR and 0.11 for QCI, the absolute values of both SII and concentration index were smaller in 2021, with ASDR's SII at -555.90, QCI's at 16.72, ASDR's concentration index at -0.13, and QCI's at 0.04. Conclusions: The global burden of COPD decreases and care quality increases over time, with notable variations across ages, sexes and SDI regions. Countries with lower SDI had disproportionately higher burden and poorer care quality for COPD.

Dose-Response Associations of Internet Use Time and Internet Addiction With Depressive Symptoms Among Chinese Children and Adolescents: Cross-Sectional Study.

Background: Children's lives are increasingly mediated by digital technologies, yet evidence regarding the associations between internet use and depression is far from comprehensive and remains unclear. Objective: This study aimed to investigate the dose-response association between internet use, including use time and addiction behaviors, and depressive symptoms among children and adolescents in Zhejiang Province. Methods: Data were collected from a school-based health survey China Common Disease and Risk Factor Surveillance Among Students, encompassing 21,336 students in Zhejiang Province. The daily internet use time, internet addiction (IA) behaviors, and depressive symptoms were assessed with questionnaires. Logistic regression models were used to explore the associations of internet use time and IA behaviors with depressive symptoms among children and adolescents. Restricted cubic spline curves were used to determine the dose-response associations. Results: A total of 6225 (29.2%) students had depressive symptoms. Compared to those reporting no internet use, boys using the internet for >2 hours/day (odds ratio [OR] 1.53, 95% CI 1.34-1.74) and girls using internet for 1.1-2 hours/day (OR 1.22, 95% CI 1.06-1.39) and >2 hours/day (OR 1.70, 95% CI 1.50-1.93) were at higher risks of depressive symptoms. A significant J-shaped association was identified between internet use time and depressive symptoms among children and adolescents, especially in boys and primary school students (nonlinear P values were .006, .003, and <.001, respectively). Increased IA behaviors were associated with a higher odd of depressive symptoms (1 IA behavior: OR 2.01, 95% CI 1.83-2.21; 2 IA behaviors: 2.91, 95% CI 2.57-3.29; and ≥3 IA behaviors: 4.72, 95% CI 4.26-5.22). A positive nonlinear association between the number of IA behaviors and depressive symptoms was found in total population, girls, and primary school students (nonlinear P values were .02, .002, .007, respectively). Conclusions: Findings suggested that excessive internet use time and IA behaviors were significantly associated with an increased risk of depressive symptoms, highlighting the importance of interventions to regulate and educate about adequate internet use during childhood and adolescence.

[Research progress in osthole for prevention and treatment of central nervous system diseases].

Central nervous system(CNS) disorders can significantly impact patients' daily lives, impairing their ability to work and imposing a substantial financial burden on their families. In recent years, the incidence of CNS diseases has shown a significant increase with the continuous improvement of the quality of life and the aging problem. Therefore, the search for new preventive and curative drugs has been a research hotspot for this group of diseases. Osthole(OST), isolated from Umbelliferae such as Cnidium monnieri, Angelica sinensis, and Heracleum hemsleyanum, possesses a variety of pharmacological effects such as neuroprotective, antioxidant, anti-inflammatory, and antithrombotic effects. There is increasing evidence that OST has demonstrated significant preventive and curative effects in various CNS disease models. This paper systematically reviewed the research progress of OST in preventing and treating CNS diseases by reviewing domestic and international literature to provide more in-depth theoretical support for the future clinical application of OST in the prevention and treatment of CNS diseases.

A ROS-Responsive Lipid Nanoparticles Release Multifunctional Hydrogel Based on Microenvironment Regulation Promotes Infected Diabetic Wound Healing.

The continuous imbalance of the diabetic wound microenvironment is an important cause of chronic nonhealing, which manifests as a vicious cycle between excessive accumulation of reactive oxygen species (ROS) and abnormal healing. Regulating the microenvironment by suppressing wound inflammation, oxidative stress, and bacterial infection is a key challenge in treating diabetic wounds. In this study, ROS-responsive hydrogels are developed composed of silk fibroin methacrylated (SFMA), modified collagen type III (rCol3MA), and lipid nanoparticles (LNPs). The newly designed hydrogel system demonstrated stable physicochemical properties and excellent biocompatibility. Moreover, the release of antimicrobial peptide (AMP) and puerarin (PUE) demonstrated remarkable efficacy in eradicating bacteria, regulating inflammatory responses, and modulating vascular functions. This multifunctional hydrogel is a simple and efficient approach for the treatment of chronic diabetic infected wounds and holds tremendous potential for future clinical applications.

Exploring the therapeutic implications of natural compounds modulating apoptosis in vascular dementia.

Vascular dementia (VaD) is a prevalent form of dementia stemming from cerebrovascular disease, manifesting in memory impairment and executive dysfunction, thereby imposing a substantial societal burden. Unfortunately, no drugs have been approved for the treatment of VaD due to its intricate pathogenesis, and the development of innovative and efficacious medications is urgently needed. Apoptosis, a programmed cell death process crucial for eliminating damaged or unwanted cells within an organism, assumes pivotal roles in embryonic development and tissue homeostasis maintenance. An increasing body of evidence indicates that apoptosis may significantly influence the onset and progression of VaD, and numerous natural compounds have demonstrated significant therapeutic potential. Here, we discuss the molecular mechanisms underlying apoptosis and its correlation with VaD. We also provide a crucial reference for developing innovative pharmaceuticals by systematically reviewing the latest research progress concerning the neuroprotective effects of natural compounds on VaD by regulating apoptosis. Further high-quality clinical studies are imperative to firmly ascertain these natural compounds' clinical efficacy and safety profiles in the treatment of VaD.

Association between 25 hydroxyvitamin D and serum uric acid level in the Chinese general population: a cross-sectional study.

BACKGROUD: The relationship between serum uric acid (SUA) and 25-hydroxyvitamin D (25(OH)D) has been variably characterized in existing literature, with inconsistent results regarding its nature and implications in the Chinese population. This study aims to clarify this association, considering the potential impact of vitamin D levels on SUA. METHODS: This cross-sectional study involved 7,086 individuals from the Second Affiliated Hospital of Zhejiang University School of Medicine, screened throughout 2020. We collected data on 25(OH)D, SUA, and other metabolic markers. Logistic regression models adjusted for confounding factors were utilized to analyze the relationships. RESULTS: Our findings illustrate a statistically significant inverted U-shaped relationship between 25(OH)D and SUA. The identified threshold effect at 28.82 ng/ml is pivotal; with 25(OH)D levels below this point associated with an increased risk of hyperuricemia (odds ratio: 1.0146, p = 0.0148), and levels above it offering protective benefits (odds ratio: 0.9616, p = 0.0164). CONCLUSIONS: Our findings confirm a nonlinear, inverted U-shaped correlation between 25(OH)D and SUA, emphasizing the importance of maintaining vitamin D levels within a specific range to effectively manage hyperuricemia. These results support the implementation of personalized vitamin D supplementation strategies to optimize metabolic health outcomes, highlighting the complex interplay between vitamin D status and uric acid levels.

Ursolic acid, an inhibitor of TMEM16A, co-loaded with cisplatin in hydrogel drug delivery system for multi-targeted therapy of lung cancer.

The efficacy of single chemotherapy drugs in cancer treatment is often limited. Combining administration targeting multiple targets has emerged as an effective strategy to improve cancer treatment. Ursolic acid, a triterpenoid compound in various natural foods, was identified as a novel inhibitor of lung cancer specific target TMEM16A. The IC50 of ursolic acid on the whole-cell current of TMEM16A was 13.85 ± 1.64 µM. Molecular dynamics simulations and site-directed mutagenesis experiments indicated the binding sites of ursolic acid on TMEM16A as L381, R535, E623, and C625. Ursolic acid significantly inhibited the proliferation and migration of LA795 cells, while promoting cancer cell apoptosis. Mechanistic studies revealed that ursolic acid inhibited lung cancer through the MAPK and EMT pathways, and induced DNA and membrane damage. Next, a degradable and self-repairing hydrogel drug-loading system was designed to enhance the targeting effect of the ursolic acid and cisplatin drug combination. In vivo experiments showed that the hydrogel-loaded ursolic acid and cisplatin enhanced the antitumor activity and reduced the toxicity. This study presents a novel approach of multi-target combination therapy using ursolic acid and cisplatin, combined with the targeted delivery capability of the hydrogel system, which significantly improves the therapeutic efficacy in lung cancer.

Targeted Delivery Strategies for Multiple Myeloma and Their Adverse Drug Reactions.

Currently, multiple myeloma (MM) is a prevalent hematopoietic system malignancy, known for its insidious onset and unfavorable prognosis. Recently developed chemotherapy drugs for MM have exhibited promising therapeutic outcomes. Nevertheless, to overcome the shortcomings of traditional clinical drug treatment, such as off-target effects, multiple drug resistance, and systemic toxicity, targeted drug delivery systems are optimizing the conventional pharmaceuticals for precise delivery to designated sites at controlled rates, striving for maximal efficacy and safety, presenting a promising approach for MM treatment. This review will delve into the outstanding performance of antibody-drug conjugates, peptide-drug conjugates, aptamer-drug conjugates, and nanocarrier drug delivery systems in preclinical studies or clinical trials for MM and monitor their adverse reactions during treatment.

Prognostic patterns in invasion lymph nodes of lung adenocarcinoma reveal distinct tumor microenvironments.

Tumor-draining lymph nodes (TDLNs) are usually the first station of tumor metastasis in lung cancer. TDLNs+ have distinct pathomorphologic and tumor microenvironment (TME)-compositional patterns, which still need to be thoroughly investigated in lung adenocarcinoma (LUAD). Here, we enrolled 312 LUAD patients with TDLNs+ from our institution between 2015 and 2019. 3DHISTECH was used to scan all of the TDLNs+. Based on morphologic features, TDLNs+ patterns were classified as polarized-type or scattered-type, and TME-compositional patterns were classified as colloid-type, necrosis-type, specific-type, and common-type. Multivariate analysis revealed an increased risk of early recurrence associated with scattered-type (HR 2.37, 95% CI: 1.06-5.28), colloid-type (HR 1.95, 95% CI: 1.03-3.67), and necrosis-type (HR 2.21, 95% CI: 1.13-4.89). NanoString transcriptional analysis revealed an immunosuppression and vascular invasion hallmark in scattered and necrosis patterns and an immunoactivated hallmark in polarized and common patterns. According to imaging mass cytometry (IMC), the scattered and necrosis patterns revealed that germinal centers (GC) were compromised, GCB cell and T cell proliferation were deficient, tumor cells had the potential for proliferation, and the immune attack may be weaker. In this study, we present evidence that LUAD patients have distinct patterns and immune hallmarks of TDLNs+ related to their prognosis.

Efficient Expression and Application of a Modified Rhizomucor miehei Lipase for Simultaneous Production of Biodiesel and Eicosapentaenoic Acid Ethyl Ester from Nannochloropsis Oil.

Few reports exist on one-step enzymatic methods for the simultaneous production of biodiesel and eicosapentaenoic acid ethyl ester (EPA-EE), a high-value pharmaceutical compound. This study aimed to efficiently express Rhizomucor miehei lipase (pRML) in Pichia pastoris X-33 via propeptide mutation and high-copy strain screening. The mutated enzyme was then used to simultaneously catalyze the production of both biodiesel and EPA-EE. The P46N mutation in the propeptide (P46N-pRML) significantly boosted its production, with the four-copy strain increasing enzyme yield by 3.7-fold, reaching 3425 U/mL. Meanwhile, its optimal temperature increased to 45-50 °C, pH expanded to 7.0-8.0, specific activity doubled, Km reduced to one-third, and kcat/Km increased 7-fold. Notably, P46N-pRML efficiently converts Nannochloropsis gaditana oil's eicosapentaenoic acid (EPA). Under optimal conditions, it achieves up to 93% biodiesel and 92% EPA-EE yields in 9 h. Our study introduces a novel, efficient one-step green method to produce both biodiesel and EPA-EE using this advanced enzyme.

High-sensitivity detection of glycoproteins by high-density boric acid modified metal-organic framework surface molecularly imprinted polymers resonant light scattering sensor.

Glycoproteins are difficult to be detected by imprinting strategy due to their low natural abundance, high flexible conformation and large size. Herein, a high-density boric acid modified metal-organic framework (MOF) surface molecularly imprinted polymer (SMIP) resonant light scattering sensor was constructed for the high-sensitivity detection of target glycoproteins. A MOF with large specific surface area was selected as the substrate material to support the boric acid group with high loading density (4.66 %). The introduction of the boric acid group in the SMIP provided a high-affinity binding site for the recognition and binding of glycoproteins. Shallow surface cavities with rapid mass transfer (equilibrium time 20 min) were thus formed by surface imprinting. Furthermore, high sensitivity (limit of detection 15 pM) was achieved at physiological pH (7.4), which was conducive to the detection of glycoproteins with low natural abundance in complex biological samples and maintaining physiological activity.

Effect of Sleeve Gastric Surgery on Body Weight and Hypothalamic-Pituitary Axis Hormone Levels in Patients with Polycystic Ovary Syndrome.

BACKGROUND: Polycystic ovary syndrome (PCOS) is the most common reproductive endocrine disorder in women of reproductive age. It is difficult for patients with PCOS to achieve weight loss with conventional treatment. The aim of this study was to investigate weight loss and changes in hypothalamic-pituitary axis hormone levels in patients with PCOS combined with obesity after sleeve gastrectomy. METHODS: A retrospective analysis of 12 patients without PCOS and 24 patients with PCOS who underwent bariatric surgery at Beijing Luhe hospital from 2020 to 2022 was performed. The study assessed the changes in body weight and hormonal indexes of the hypothalamic-pituitary axis before and six months after the surgery. RESULTS: Patients with PCOS experienced greater weight loss compared to those without the condition. Following surgery, individuals with PCOS showed lower levels of postoperative testosterone, prolactin, and free testosterone indices compared to preoperative levels. Additionally, postoperative LH and FSH levels were higher than preoperative levels. Analysis of thyroid axis hormone levels revealed that FT3 and TSH levels were notably reduced in patients with PCOS postoperatively. Furthermore, growth hormone levels were found to be elevated in patients with PCOS following surgery. CONCLUSION: Bariatric surgery enhances hormone levels in the hypothalamic-pituitary axis in women with PCOS, leading to greater improvements in patients with PCOS compared to those with simple obesity.

Temporal trends and projections in the global burden of neck pain: findings from the Global Burden of Disease Study 2019.

ABSTRACT: Data were obtained from the Global Burden of Disease study 2019. Joinpoint regression model was used to analyze the temporal trends from 1990 to 2019 of neck pain burden, focusing on age-standardized incidence rates, age-standardized prevalence rates, and age-standardized years lived with disability (YLDs) rates at the global, regional, and national levels. The age-period-cohort analysis was used to estimate the effects of age (5-99 years), period (1990-2019), and cohort (1893-2012) at the global, regional, and national levels. Future projections for the global burden of neck pain from 2020 to 2044 were estimated using the nordpred age-period-cohort model. From 1990 to 2019, the global incidence, prevalence cases, and YLDs counts of neck pain have increased by 71.89%, 98.21%, and 78.17%, respectively. The joinpoint analysis indicated significant shifts in the global trends of age-standardized neck pain burden, which varied across regions and nations. The age-period-cohort model indicated that the neck pain burden was predominantly concentrated in middle-aged and older age, with period and cohort effects showing minimal variation from 1990 to 2019. Compared with 2019, the incident cases, prevalent cases, and YLDs counts of neck pain were projected to increase by 134%, 142%, and 140% by 2044. The global burden of neck pain has persisted at a relatively elevated level from 1990 to 2019, with projections indicating a continuing upward trend. Future research is urgently needed to better understand the predictors and clinical course of neck pain and to enhance prevention and management strategies.

Long-term effects of fine particulate matter components on depression among middle-aged and elderly adults in China: A nationwide cohort study.

BACKGROUND: Fine particulate matter (PM2.5) has been implicated in various health concerns. However, a comprehensive understanding of the specific PM2.5 components affecting depression remains limited. METHODS: This study conducted a Cox proportional-hazards model to assess the effect of PM2.5 components on the incidence of depression based on the China Health and Retirement Longitudinal Study (CHARLS). Participants with 10-item Center for Epidemiologic Studies Depression Scale (CESD-10) score of 10 or higher were classified as exhibiting depression. RESULTS: Our findings demonstrated a significant positive correlation between long-term exposure to black carbon (BC), sulfate (SO42-), and organic matter (OM) components of PM2.5 and the prevalence of depression. Per 1 Interquartile Range (IQR) increment in 3-year average concentrations of BC, OM, and SO42- were associated with the hazard ratio (HR) of 1.54 (95 % confidence intervals (CI): 1.44, 1.64), 1.24 (95%CI: 1.16, 1.34) and 1.25 (95%CI: 1.16, 1.35). Notably, females, younger individuals, those with lower educational levels, urban residents, individuals who were single, widowed, or divorced, and those living in multi-story houses exhibited heightened vulnerability to the adverse effects of PM2.5 components on depression. LIMITATIONS: Firstly, pollutant data is confined to subjects' fixed addresses, overlooking travel and international residence history. Secondly, the analysis only incorporates five fine particulate components, leaving room for further investigation into the remaining fine particulate components in future studies. CONCLUSIONS: This study provides robust evidence supporting the detrimental impact of PM2.5 components on depression. The identification of specific vulnerable populations contributes to a deeper understanding of the underlying mechanisms involved in the relationship between PM2.5 components and depression.

Interprovincial spatial distribution patterns and socioeconomic factors on traditional Chinese medicine (TCM) service utilization in China.

The traditional Chinese medicine (TCM) industry in China exhibits significant regional disparities in health service utilization, the underlying reasons for which are yet to be fully explored. This study employs Geodetector models to analyze the factors affecting TCM service utilization, providing the first examination of spatial distribution patterns and influencing factors for both TCM outpatient (TCMOSU) and inpatient services (TCMISU). The findings of this study reveal spatial disparities across China's provinces, showing a prevalence of TCMOSU in the east and TCMISU decreasing from southwest to northeast. Global Moran's I autocorrelation analysis revealed a positive spatial correlation between TCMOSU and TCMISU across Chinese provinces, suggesting spatial clustering and the potential for interregional collaboration in the development of TCM services. Local Moran's I autocorrelation analysis revealed clusters of TCMOSU in wealthier eastern provinces, such as Jiangsu and Tianjin, and clusters of TCMISU in the southwest. Factor detector analysis revealed that disposable income per capita was the most significant factor linking higher incomes with increased TCMOSU. In contrast, TCMISU was primarily influenced by demographic factors, such as the illiteracy rate and population urbanization rate, emphasizing traditional practices in lower education regions. Interaction detector analysis revealed the joint effects of these factors, demonstrating how regional economic status, health status, and healthcare resource indicators interact with other factors for TCMOSU and how demographic factors significantly influence the prevalence of TCMISU. This study highlights the importance of considering health status together with regional economic, demographic, and healthcare resources when formulating TCM healthcare policies and allocating such resources in China. Promoting the balanced and coordinated regional development of TCM services across the country requires the development of strategies that account for these varied regional characteristics.

The combined effects of polystyrene of different sizes and cadmium in mouse kidney tissues.

Environmental accumulation of nano- and microplastics pose serious risks to human health. Polystyrene (PS) is a polymer commonly used in the production of plastics. However, PS can adsorb cadmium (Cd), thereby influencing bioavailability and toxicity in vivo. Moreover, PS and Cd can accumulate in the mammalian kidney. Therefore, the aim of the present study was to assess the effects of combined exposure to PS and Cd in the kidney. Kidney damage was evaluated in male mice gavaged with PS (diameter, 100 nm and/or 1 µm) and Cd for 25 days.The results showed that PS at 100 nm caused more severe oxidative damage and cell apoptosis than PS at 1 µm. Combined exposure to PS at both 100 nm and 1 µm caused more severe kidney damage than the single administration groups. The extent of kidney toxicity caused by Cd differed with the combination of PS particles at 100 nm vs. 1 µm. The degree of damage to kidney function, pathological changes, and cell apoptosis induced by Cd+100 nm PS+1µm PS was the most severe. An increase in the Bax/Bcl2 ratio and overexpression of p53 and caspase-3 revealed that renal cell apoptosis might be induced via the mitochondrial pathway. Collectively, these findings demonstrate that the size of PS particles dictates the combined effects of PS and Cd in kidney tissues. Kidney damage caused by the combination of different sizes of PS particle and Cd is more complicated under actual environmental conditions.

Manipulating the Spin State of Spinel Octahedral Sites via a π-π Type Orbital Coupling to Boost Water Oxidation.

Spin state is often regarded as the crucial valve to release the reactivity of energy-related catalysts, yet it is also challenging to precisely manipulate, especially for the active center ions occupied at the specific geometric sites. Herein, a π-π type orbital coupling of 3d (Co)-2p (O)-4f (Ce) was employed to regulate the spin state of octahedral cobalt sites (CoOh) in the composite of Co3O4/CeO2. More specifically, the equivalent high-spin ratio of CoOh can reach to 54.7 % via tuning the CeO2 content, thereby triggering the average eg filling (1.094) close to the theoretical optimum value. The corresponding catalyst exhibits a superior water oxidation performance with an overpotential of 251 mV at 10 mA cm-2, rivaling most cobalt-based oxides state-of-the-art. The π-π type coupling corroborated by the matched energy levels between Ce t1u/t2u-O and CoOh t2g-O π type bond in the calculated crystal orbital Hamilton population and partial density of states profiles, stimulates a π-donation between O 2p and π-symmetric Ce 4fyz 2 orbital, consequently facilitating the electrons hopping from t2g to eg orbital of CoOh. This work offers an in-depth insight into understanding the 4f and 3d orbital coupling for spin state optimization in composite oxides.

Inhibitory effect and molecular mechanism on tyrosinase and browning of fresh-cut apple by longan shell tannins.

Tyrosinase is a biological macromolecule closely related to browning of fruit and vegetables, melanin production, and tyrosinase inhibitors are usually used to prevent browning and pigmentation. In this study, longan shell tannins (LSTs) were screened as tyrosinase inhibitors and their structures were proved to be mixtures of procyanidins (condensed tannins) and ellagitannins (hydrolyzed tannins). Enzymatic experiments verified that LSTs were efficient inhibitors, and the IC50 values for monophenolase and bisphenolase were 176.04 ± 10 and 59.94 ± 5 µg mL-1, respectively. Fluorescence detections and molecular docking revealed that the combination of LSTs to tyrosinase was mainly driven by hydrogen bonding, hydrophobic interaction, as well as van der Waals force, which changed the microenvironment of tyrosine and tryptophan residues as well as enzyme conformation. Circular dichroism and molecular dynamics simulation showed that LSTs affected secondary structures of tyrosinase, resulting in structural stretching and conformational modification of the enzyme. In addition, preservation studies demonstrated that LSTs owned the ability to delay the browning of fresh-cut apples by inhibiting phenolic metabolism, strengthening the antioxidant system, and reducing lipid peroxidation. This paper testified that LSTs are exteaordinary tyrosinase inhibitors, and offered a scientific foundation for the application of LSTs in food industry and medicine.

Tuning quantum dots emission on DNA tetrahedron/silica nanosphere/graphene oxide nanointerface for ratiometric fluorescence assay of Pb2+ in multiplex samples.

BACKGROUND: Assembling framework nucleic acid (FNA) nanoarchitectures and tuning luminescent quantum dots (QDs) for fluorescence assays represent a versatile strategy in analytical territory. Rationally, FNA constructs could offer a preferential orientation to efficiently recognize the target and improve detection sensitivity, meanwhile, regulating size-dependent multicolor emissions of QDs in one analytical setting for ratiometric fluorescence assay would greatly simplify operation procedures. Nonetheless, such FNA/QDs-based ratiometric fluorescence nanoprobes remain rarely explored. RESULTS: We designed a sensitive and signal amplification-free fluorescence aptasensor for lead ions (Pb2+) that potentially cause extensive contamination to environment, cosmetic, food and pharmaceuticals. Red and green emission CdTe quantum dots (rQDs and gQDs) were facilely prepared. Moreover, silica nanosphere encapsulating rQDs served as quantitative internal reference and scaffold to anchor a predesigned FNA and DNA sandwich containing Pb2+ binding aptamer and gQD modified DNA signal reporter. On binding of Pb2+, the gQD-DNA signal reporter was set free, resulting in fluorescence quenching at graphene oxide (GO) interface. Owing to the rigid structure of FNA, the fluorescence signal reporter orderly arranged at the silica nanosphere could sensitively respond to Pb2+ stimulation. The dose-dependent fluorescence signal-off mode enabled ratiometric analysis of Pb2+ without cumbersome signal amplification. Linear relationship was established between fluorescence intensity ratio (I555/I720) and Pb2+ concentration from 10 nM to 2 µM, with detection limit of 1.7 nM (0.43 ppb), well addressing the need for Pb2+ routine monitoring. The designed nanoprobe was applied to detection of Pb2+ in soil, cosmetic, milk, drug, and serum samples, with the sensitivity comparable to conventional ICP-MS technique. SIGNIFICANCE: Given the programmable design of FNA and efficient recognition of target, flexible tuning of QDs emission, and signal amplification-free strategy, the present fluorescence nanoprobe could be a technical criterion for other heavy metal ions detection in a straightforward manner.