Applying the Consolidated Framework for Implementation Research to investigate factors of implementing alcohol screening and brief intervention among primary care physicians and nurses in Hong Kong, China: an exploratory sequential mixed-method study.

BACKGROUND: Alcohol screening and brief intervention (SBI) is an evidence-based intervention recommended by the World Health Organization. This study applied the Consolidated Framework for Implementation Research (CFIR) to understand facilitators and barriers of SBI implementation in primary care settings in Hong Kong, China. METHODS: This was a sequential mixed-method study. In-depth interviews of 21 physicians and 20 nurses working in the primary care settings from the public and private sectors were first conducted to identify CFIR constructs that were relevant to SBI implementation in the Chinese context and potential factors not covered by the CFIR. A questionnaire was then developed based on the qualitative findings to investigate factors associated with SBI implementation among 282 physicians and 295 nurses. RESULTS: The in-depth interviews identified 22 CFIR constructs that were facilitators or barriers of SBI implementation in Hong Kong. In addition, the stigmatization of alcohol dependence was a barrier and the belief that it was important for people to control the amount of alcohol intake in any situation was mentioned as a facilitator to implement SBI. In the survey, 22% of the participants implemented SBI in the past year. Factors associated with the SBI implementation echoed most of the qualitative findings. Among physicians and nurses in both sectors, they were more likely to implement SBI when perceiving stronger evidence supporting SBI, better knowledge and self-efficacy to implement SBI, more available resources, and clearer planning for SBI implementation in the clinics but less likely to do so when perceiving SBI implementation to be complicated and of higher cost, and drinking approved by the Chinese culture. Participants were more likely to implement SBI when perceiving SBI fit better with the existing practice and better leadership engagement in the public sector, but not in the private sector. Perceiving a stronger need and greater importance to implement SBI were associated with higher likelihood of SBI implementation among physicians, but not among nurses. Perceiving better organizational culture supporting SBI was positively associated with SBI implementation among nurses, but not among physicians. CONCLUSIONS: There was a significant gap between SBI evidence and its implementation. Some strategies to improve SBI implementation may be different between physicians and nurses and between those in the public and private sectors. The CFIR is a useful framework for understanding facilitators and barriers of SBI implementation in primary care settings.

HMGB1: A New Target for Ischemic Stroke and Hemorrhagic Transformation.

Stroke in China is distinguished by its high rates of morbidity, recurrence, disability, and mortality. The ultra-early administration of rtPA is essential for restoring perfusion in acute ischemic stroke, though it concurrently elevates the risk of hemorrhagic transformation. High-mobility group box 1 (HMGB1) emerges as a pivotal player in neuroinflammation after brain ischemia and ischemia-reperfusion. Released passively by necrotic cells and actively secreted, including direct secretion of HMGB1 into the extracellular space and packaging of HMGB1 into intracellular vesicles by immune cells, glial cells, platelets, and endothelial cells, HMGB1 represents a prototypical damage-associated molecular pattern (DAMP). It is intricately involved in the pathogenesis of atherosclerosis, thromboembolism, and detrimental inflammation during the early phases of ischemic stroke. Moreover, HMGB1 significantly contributes to neurovascular remodeling and functional recovery in later stages. Significantly, HMGB1 mediates hemorrhagic transformation by facilitating neuroinflammation, directly compromising the integrity of the blood-brain barrier, and enhancing MMP9 secretion through its interaction with rtPA. As a systemic inflammatory factor, HMGB1 is also implicated in post-stroke depression and an elevated risk of stroke-associated pneumonia. The role of HMGB1 extends to influencing the pathogenesis of ischemia by polarizing various subtypes of immune and glial cells. This includes mediating excitotoxicity due to excitatory amino acids, autophagy, MMP9 release, NET formation, and autocrine trophic pathways. Given its multifaceted role, HMGB1 is recognized as a crucial therapeutic target and prognostic marker for ischemic stroke and hemorrhagic transformation. In this review, we summarize the structure and redox properties, secretion and pathways, regulation of immune cell activity, the role of pathophysiological mechanisms in stroke, and hemorrhage transformation for HMGB1, which will pave the way for developing new neuroprotective drugs, reduction of post-stroke neuroinflammation, and expansion of thrombolysis time window.

Computer-aided diagnosis system for optical diagnosis of colorectal polyps under white light imaging.

OBJECTIVES: This study presents a novel computer-aided diagnosis (CADx) designed for optically diagnosing colorectal polyps using white light imaging (WLI).We aimed to evaluate the effectiveness of the CADx and its auxiliary role among endoscopists with different levels of expertise. METHODS: We collected 2,324 neoplastic and 3,735 nonneoplastic polyp WLI images for model training, and 838 colorectal polyp images from 740 patients for model validation. We compared the diagnostic accuracy of the CADx with that of 15 endoscopists under WLI and narrow band imaging (NBI). The auxiliary benefits of CADx for endoscopists of different experience levels and for identifying different types of colorectal polyps was also evaluated. RESULTS: The CADx demonstrated an optical diagnostic accuracy of 84.49%, showing considerable superiority over all endoscopists, irrespective of whether WLI or NBI was used (P < 0.001). Assistance from the CADx significantly improved the diagnostic accuracy of the endoscopists from 68.84% to 77.49% (P = 0.001), with the most significant impact observed among novice endoscopists. Notably, novices using CADx-assisted WLI outperform junior and expert endoscopists without such assistance. CONCLUSIONS: The CADx demonstrated a crucial role in substantially enhancing the precision of optical diagnosis for colorectal polyps under WLI and showed the greatest auxiliary benefits for novice endoscopists.

Chaotropic Effect-Induced Sol-Gel Transition and Radical Stabilization for Bacterially Sensitive Near-Infrared Photothermal Therapy.

Deep-seated bacterial infections (DBIs) are stubborn and deeply penetrate tissues. Eliminating deep-seated bacteria and promoting tissue regeneration remain great challenges. Here, a novel radical-containing hydrogel (SFT-B Gel) cross-linked by a chaotropic effect was designed for the sensing of DBIs and near-infrared photothermal therapy (NIR-II PTT). A silk fibroin solution stained with 4,4',4″-(1,3,5-triazine-2,4,6-triyl)tris(1-methylpyridin-1-ium) (TPT3+) was employed as the backbone, which could be cross-linked by a closo-dodecaborate cluster (B12H122-) through a chaotropic effect to form the SFT-B Gel. More interestingly, the SFT-B Gel exhibited the ability to sense DBIs, which could generate a TPT2+• radical with obvious color changes in the presence of bacteria. The radical-containing SFT-B Gel (SFT-B★ Gel) possessed strong NIR-II absorption and a remarkable photothermal effect, thus demonstrating excellent NIR-II PTT antibacterial activity for the treatment of DBIs. This work provides a new approach for the construction of intelligent hydrogels with unique properties using a chaotropic effect.

Patterns of sex behaviors and factors associated with condomless anal intercourse during the COVID-19 pandemic among men who have sex with men in Hong Kong: A cross-sectional study.

OBJECTIVES: The present study examined the patterns of sex behaviors before and during COVID-19, and identified the factors associated with condomless anal intercourse during COVID-19 from individual, interpersonal, and contextual level among men who have sex with men (MSM) in Hong Kong. METHODS: A cross-sectional study was conducted among MSM in Hong Kong. A total of 463 MSM completed a cross-sectional telephone survey between March 2021 and January 2022. RESULTS: Among all participants, the mean number of regular sex partners, non-regular sex partners, and casual sex partners during the COVID-19 period were 1.24, 2.09, and 0.08 respectively. Among those who had sex with regular, non-regular, and casual sex partner during the COVID-19 period, respectively 52.4%, 31.8% and 46.7% reported condomless anal intercourse. Compared to the pre-COVID-19 period, participants reported significantly fewer number of regular and non-regular sex partners during the COVID-19 period. However, a higher level of condomless anal intercourse with all types of sex partners during the COVID-19 period was also observed. Adjusted for significant socio-demographic variables, results from logistic regression analyses revealed that perceived severity of COVID-19 (aOR = 0.72, 95% CI = 0.58, 0.88), COVID-19 risk reduction behaviors in general (aOR = 0.68, 95% CI = 0.48, 0.96), COVID-19 risk reduction behaviors during sex encounters (aOR = 0.45, 95% CI = 0.30, 0.66), condom negotiation (aOR = 0.61, 95% CI = 0.44, 0.86), and collective efficacy (aOR = 0.79, 95% CI = 0.64, 0.98) were protective factors of condomless anal intercourse with any type of sex partners during the COVID-19 period. CONCLUSION: The COVID-19 control measures have caused a dramatic impact on the sexual behavior of MSM in Hong Kong. Interventions that promote condom use during the COVID-19 pandemic are still needed and such interventions could emphasize prevention of both COVID-19 and HIV.

Exploring mother-daughter communication and social media influence on HPV vaccine refusal for daughters aged 9-17 years in a cross-sectional survey of 11,728 mothers in China.

This study investigated the influences of mother-daughter communication and social media on mothers' HPV vaccine refusal for their daughters aged 9-17. A cross-sectional online survey among 11,728 mothers of girls aged 9-17 in Shenzhen, China was implemented between July and October 2023. Multi-level logistic regression models were fitted. Among 11,728 participants, 43.2% refused to have their daughters receive an HPV vaccination. In multivariate analysis, more openness in the mother-daughter communication (AOR: 0.99, 95%CI: 0.98, 0.99), perceived more positive outcomes of mother-daughter communication (AOR: 0.77, 95%CI: 0.75, 0.79), higher frequency of exposure to testimonials about daughters' HPV vaccination (AOR: 0.81, 95%CI: 0.78, 0.85) and information encouraging parents to vaccinate their daughters against HPV on social media (AOR: 0.76, 95%CI: 0.73, 0.79), and thoughtful consideration of the veracity of the information specific to HPV vaccines (AOR: 0.80, 95%CI: 0.77, 0.83) were associated with lower vaccine refusal. Mothers who were not the main decision-makers of daughters' HPV vaccination (AOR: 1.28 to 1.46), negative outcome expectancies of mother-daughter communication (AOR: 1.06, 95%CI: 1.04, 1.08), and mothers' HPV vaccine refusal (AOR: 2.81, 95%CI: 2.58, 3.06) were associated with higher vaccine refusal for their daughters. The level of mothers' HPV vaccine refusal for their daughters was high in China. Openness and outcome expectancies of mother-daughter communication and information exposure on social media were considered key determinants of HPV vaccine refusal for daughters. Future HPV vaccination programs should consider these interpersonal factors.

In situ grown Bi2WO6@CoMoO4 layered cladding structure on carbon nanofibers by a two-step solvothermal method and Ti mesh substrate as advanced counter electrodes for dye-sensitized solar cells.

Based on carbon nanofibers (CNFs) with excellent electrical conductivity, a three-layer cladding structure CNFs@Bi2WO6@CoMoO4 material was prepared by a two-step solvothermal method, which effectively combines the great catalytic ability of transition metal oxides with the good conductivity of CNFs. Titanium (Ti) mesh was used as the conductive substrate and CNFs@Bi2WO6@CoMoO4 was scraped on it to prepare paired counter electrodes (CEs), and then dye-sensitized solar cells (DSSCs) were assembled by unifying with photoanode and iodine electrolyte. The photoelectric conversion efficiency (PCE) of 9.41% (with Voc of 0.784 V, Jsc of 17.90 mA cm-2 and FF of 0.72) was obtained under standard light conditions (AM 1.5 G). In brief, this study found a cheaper and better alternative material for Pt and also provides more possibilities for the selection of conductive substrate for CEs.

Supramolecular coordination platinum metallacycle-based multilevel wound dressing for bacteria sensing and wound healing.

The exploitation of novel wound healing methods with real-time infection sensing and high spatiotemporal precision is highly important for human health. Pt-based metal-organic cycles/cages (MOCs) have been employed as multifunctional antibacterial agents due to their superior Pt-related therapeutic efficiency, various functional subunits and specific geometries. However, how to rationally apply these nanoscale MOCs on the macroscale with controllable therapeutic output is still challenging. Here, a centimeter-scale Pt MOC film was constructed via multistage assembly and subsequently coated on a N,N'-dimethylated dipyridinium thiazolo[5,4-d]thiazole (MPT)-stained silk fabric to form a smart wound dressing for bacterial sensing and wound healing. The MPT on silk fabric could be used to monitor wound infection in real-time through the bacteria-mediated reduction of MPT to its radical form via a color change. The MPT radical also exhibited an excellent photothermal effect under 660 nm light irradiation, which could not only be applied for photothermal therapy but also induce the disassembly of the Pt MOC film suprastructure. The highly ordered Pt MOC film suprastructure exhibited high biosafety, while it also showed improved antibacterial efficiency after thermally induced disassembly. In vitro and in vivo studies revealed that the combination of the Pt MOC film and MPT-stained silk can provide real-time information on wound infection for timely treatment through noninvasive techniques. This study paves the way for bacterial sensing and wound healing with centimeter-scale metal-organic materials.

Influences of mpox disease perceptions, sources and contents of information exposure on mpox vaccine uptake among gay, bisexual, and other men who have sex with men in Hong Kong, China.

BACKGROUND: Following the global mpox outbreak in 2022, multiple regions in Asia have been reporting ongoing mpox cases within high-risk groups, including gay, bisexual, and other men who have sex with men (GBMSM). An optimal level of vaccination rate is essential to prevent further mpox outbreaks. However, no existing studies have examined mpox vaccine uptake among GBMSM in East Asia. METHODS: A cross-sectional survey was conducted among a sample of 531 GBMSM in Hong Kong, China, between March and October 2023. The study used multivariable logistic regression models to investigate the associations between mpox-related disease perceptions, exposures to sources and contents of mpox-related information, and mpox vaccine uptake. RESULTS: The prevalence of mpox vaccine uptake among GBMSM in Hong Kong was 21.7%, with 7.7% completing one dose and 13.9% completing two doses. GBMSM who were younger or earning less monthly income were less likely to have been vaccinated. After adjusting for confounding variables, participants who perceived more negative impacts on their lives if they were to contract mpox, more severe symptoms, and a more coherent understanding of mpox were positively associated with mpox vaccine uptake. In addition, more frequent exposure to information through the following sources: TV, newspaper, radio and posters, government websites, news websites or apps, other people's social media, and communication over the phone or face-to-face was positively associated with mpox vaccine uptake. Finally, more frequent exposure to the following information contents: mpox statistics from other countries, the Hong Kong government's responses to mpox cases, negative information about patients with mpox, and information on prevention and treatment of mpox were positively associated with mpox vaccine uptake. CONCLUSIONS: This study provides timely and evidence-based implications to address health communication and messaging needs in promoting mpox vaccination among GBMSM in Hong Kong, relevant to regions with similar sociocultural contexts.

Men who have sex with men were more depressed than their counterparts because of lower social support and higher loneliness: A comparative survey among Chinese university students.

BACKGROUND: Poor mental health is prevalent among men who have sex with men (MSM), including MSM university students (MSMUS), causing a significant burden on their health and society. The study aimed to compare the difference in levels of depressive symptoms between Chinese MSMUS and non-MSMUS and test the mediating roles of social support and loneliness in the relationship between MSM status and depressive symptoms among male university students. METHODS: From June to October 2018, a total of 305 MSMUS and 2447 non-MSMUS from two cities in Sichuan province (China) were investigated using questionnaires. RESULTS: The proportion of depression in the MSMUS and non-MSMUS groups was 54.1 % and 36.4 %, respectively. MSM status, social support, and loneliness were all significantly associated with depressive symptoms among Chinese university students. Structural equation modelling showed that the association between MSM status and depressive symptoms was partially mediated by three indirect paths, including 1) via social support (mediated proportion = 19.4 %), 2) via loneliness (mediated proportion = 19.3 %), and 3) via social support and then loneliness (mediated proportion = 16.1 %). CONCLUSIONS: Depression was prevalent among university students in China, especially MSMUS. The findings increased our understanding of the mediating roles of social support and loneliness in the link between MSM status and depressive symptoms among Chinese male university students, which have great implications for designing interventions to improve their mental health. LIMITATION: The cross-sectional study design limited causal inferences.

On rheological properties of disc-shaped cellulose nanocrystals.

The rheological properties of a substance depend greatly on its morphology, and rod-shaped cellulose nanocrystals (RCNCs) and cellulose nanofibrils (CNFs) have been extensively studied for their rheological properties. Nevertheless, the rheological properties of disc-shaped cellulose nanocrystals (DCNCs) with crystalline allomorph II derived from mercerized cellulose remain unknown yet. This work investigated the DCNCs' rheological properties in depth using steady-shear and oscillation measurements. At the same concentration, DCNC's suspension viscosity is lower than that of RCNC; RCNC has an instinct viscosity of 258.2, while DCNC has 187.9. Comparing RCNC suspensions with cellulose nanorods, DCNC has a lower aspect ratio and exhibits a distinct steady shear behavior. Under polarized film, DCNC suspension cannot self-assemble into chiral or liquid crystal phases, and with increasing concentrations, the system transitions from an isotropic phase to a gel phase. Oscillation sweeps demonstrate that the gel transition occurs at 7 %-8 %. Based on thixotropic recovery sweep outcomes, the high-stress oscillations enhance the network structure of DCNC suspensions, which is significantly different from that of RCNC suspensions. Results demonstrate the unique properties of DCNC, highlighting its application as a rheological modifier.

Integrating a Biomineralized Nanocluster for H2S-Sensitized ROS Bomb against Breast Cancer.

Nanomaterial-assisted chemodynamic therapy (CDT) has received considerable attention in recent years. It outperforms other modalities by its distinctive reactive oxygen species (ROS) generation through a nonexogenous stimulant. However, CDT is limited by the insufficient content of endogenous hydrogen peroxide (H2O2). Herein, a biodegradable MnS@HA-DOX nanocluster (MnS@HA-DOX NC) was constructed by in situ biomineralization from hyaluronic acid, to enlarge the ROS cascade and boost Mn2+-based CDT. The acid-responsive NCs could quickly degrade after internalization into endo/lysosomes, releasing Mn2+, H2S gas, and anticancer drug doxorubicin (DOX). The Fenton-like reaction catalyzed by Mn2+ was amplified by both H2S and DOX, producing a mass of cytotoxic ·OH radicals. Through the combined action of gas therapy (GT), CDT, and chemotherapy, oxidative stress would be synergistically enhanced, inducing irreversible DNA damage and cell cycle arrest, eventually resulting in cancer cell apoptosis.

Epigenetic marks or not? The discovery of novel DNA modifications in eukaryotes.

DNA modifications add another layer of complexity to the eukaryotic genome to regulate gene expression, playing critical roles as epigenetic marks. In eukaryotes, the study of DNA epigenetic modifications has been confined to 5mC and its derivatives for decades. However, rapid developing approaches have witnessed the expansion of DNA modification reservoirs during the past several years, including the identification of 6mA, 5gmC, 4mC, and 4acC in diverse organisms. However, whether these DNA modifications function as epigenetic marks requires careful consideration. In this review, we try to present a panorama of all the DNA epigenetic modifications in eukaryotes, emphasizing recent breakthroughs in the identification of novel DNA modifications. The characterization of their roles in transcriptional regulation as potential epigenetic marks is summarized. More importantly, the pathways for generating or eliminating these DNA modifications, as well as the proteins involved are comprehensively dissected. Furthermore, we briefly discuss the potential challenges and perspectives, which should be taken into account while investigating novel DNA modifications.

Inactivated COVID-19 vaccination and SARS-CoV-2 infection among Chinese adults in the "living with COVID" era.

The objective of this research was to examine the correlation between the status of inactivated COVID-19 vaccination and self-reported confirmed SARS-CoV-2 infection among adults after China entered the "living with COVID" era. A cross-sectional online survey was conducted among parents or guardians of students attending all 220 kindergartens and 105 primary or secondary schools in Longhua District of Shenzhen, China during March 1 to 9, 2023. The participating schools invited all parents or guardians of their students to complete the online survey. The study focused on a sub-sample of 68,584 participants who were either unvaccinated (n = 2152) or only receiving inactivated COVID-19 vaccination (n = 66,432). Logistic regression was employed for data analysis. Prior to the implementation of the "living with COVID" policy, 83.5% of the participants received three doses of inactivated COVID-19 vaccines; 63.0% reported being infected with the SARS-CoV-2 after the policy change. In a multivariate analysis, participants who had received a third dose within the past 6 months were less likely to be infected with SARS-CoV-2, as compared to those who had not completed the primary vaccination series (4-6 months: AOR: 0.84, 95%CI: 0.77, 0.92; ≤3 months: AOR: 0.82, 95%CI: 0.73, 0.92). Despite the high coverage, our results suggested that three doses of inactivated COVID-19 vaccines did not provide adequate protection against SARS-CoV-2 infection among Chinese adults.

Counseling Supporting HIV Self-Testing and Linkage to Care Among Men Who Have Sex With Men: Systematic Review and Meta-Analysis.

BACKGROUND: Counseling supporting HIV self-testing (HIVST) is helpful in facilitating linkage to care and promoting behavior changes among men who have sex with men (MSM). Different levels of counseling support for MSM HIVST users may lead to variance in the linkage to care. OBJECTIVE: This study aims to synthesize evidence on counseling supporting MSM HIVST users and to conduct a meta-analysis to quantify the proportion of MSM HIVST users who were linked to care. METHODS: A systematic search was conducted using predefined eligibility criteria and relevant keywords to retrieve studies from the MEDLINE, Global Health, Web of Science, Embase, APA PsycINFO, and Scopus databases. This search encompassed papers and preprints published between July 3, 2012, and June 30, 2022. Studies were eligible if they reported counseling supporting HIVST or quantitative outcomes for linkage to care among MSM and were published in English. The screening process and data extraction followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The quality of the included studies was assessed by the National Institutes of Health quality assessment tool. Data were extracted using random effects models to combine the proportion of HIVST users who were linked to care. Subgroup analyses and metaregression were conducted to assess whether linkage to care varied according to study characteristics. All analyses were performed with R (version 4.2.1; R Foundation for Statistical Computing) using the metafor package. RESULTS: A total of 55 studies published between 2014 and 2021, including 43 observational studies and 12 randomized controlled trials, were identified. Among these studies, 50 (91%) provided active counseling support and 5 (9%) provided passive counseling support. In studies providing active counseling support, most MSM HIVST users were linked to various forms of care, including reporting test results (97.2%, 95% CI 74.3%-99.8%), laboratory confirmation (92.6%, 95% CI 86.1%-96.2%), antiretroviral therapy initiation (90.8%, 95% CI 86.7%-93.7%), and referral to physicians (96.3%, 95% CI 85%-99.2%). In studies providing passive counseling support, fewer MSM HIVST users were linked to laboratory confirmation (78.7%, 95% CI 17.8%-98.4%), antiretroviral therapy initiation (79.1%, 95% CI 48.8%-93.7%), and referral to physicians (79.1%, 95% CI 0%-100%). Multivariate metaregression indicated that a higher number of essential counseling components, a smaller sample size (<300), and the use of mobile health technology to deliver counseling support were associated with better linkage to care. The quality of the studies varied from fair to good with a low to high risk of bias. CONCLUSIONS: Proactively providing counseling support for all users, involving a higher number of essential components in the counseling support, and using mobile health technology could increase the linkage to care among MSM HIVST users. TRIAL REGISTRATION: PROSPERO CRD42022346247; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=346247.

Coverage with the First Dose of Human Papillomavirus Vaccination among Females Aged 9-50 Years in Shenzhen, China: A Surveillance Based on Administrative Health Records in 2023.

China started to offer human papillomavirus (HPV) vaccines to females aged 9-45 years in 2016. However, there was a lack of reports about HPV vaccination coverage in a representative sample of females in China. Therefore, this study aimed to examine the current HPV coverage and associated factors among females aged 9-50 years in Shenzhen, China, based on administrative health records kept by community health centers. A multistage random sampling approach was used. The research team randomly selected 18 community health centers in Shenzhen, and 3118 health records of females aged 9-50 years were then randomly selected from these health centers. Among all participants, 18.7% received at least one dose of HPV vaccination. The highest coverage was observed among females aged 18-26 years (23.4%), followed by those aged 27-35 years (22.0%) and 36-45 years (20.2%). Such coverage was very low among females aged 9-17 years (4.6%) and those aged 46-50 years (3.2%). Among females aged 18 years or above, higher education level, having a family doctor, and permanent residency in Shenzhen were associated with higher HPV vaccination coverage, while older age and being married/divorced were negatively associated with coverage. The HPV vaccination coverage in Shenzhen was 18.7% and there is a strong need for improvement.

Heat accumulation and phase transition induction in a VO2 thin film by a femtosecond pulse-periodic radiation.

The kinetics of optical switching due to the insulator-metal phase transition in a VO2 thin film is studied experimentally at different laser pulse repetition frequencies (PRFs) in the NIR range and compared with temperature kinetics obtained through the thermal conductance calculations. Two switching processes have been found with characteristic times <2 ms and <15 ms depending on the PRF; the former is explained by the accumulation of metallic domains remaining after a single-pulse phase transition, and the latter is referred to the heat accumulation in the film. Consequently, the dynamics of the microscopic domains is leading in the initiation of phase transition under pulse-periodic conditions compared to the macroscopic heat transfer. The reverse transition at the radiation turn-off depends on the PRF with a time coefficient of 17.5 µs/kHz and is determined by the metallic domains' decay in the film. The results are important for understanding the nature of the insulator-metal transition in thin films of VO2 as well as using them in all-optical switches of pulse-periodic laser radiation.

Identification of triangular single crystals of transition metal dichalcogenides based on the detection algorithm.

The distinctive properties and facile integration of 2D materials hold the potential to offer promising avenues for the on-chip photonic devices, and the expeditious and nondestructive identification and localization of diverse fundamental building blocks become key prerequisites. Here, we present a methodology grounded in digital image processing and deep learning, which effectively achieves the detection and precise localization of four monolayer-thick triangular single crystals of transition metal dichalcogenides with the mean average precision above 90%, and the approach demonstrates robust recognition capabilities across varied imaging conditions encompassing both white light and monochromatic light. This stands poised to serve as a potent data-driven tool enhancing the characterizing efficiency and holds the potential to expedite research initiatives and applications founded on the utilization of 2D materials.

Mechanism of the Visible-Light-Promoted C(sp3)-H Oxidation via Uranyl Photocatalysis.

Uranyl cation, as an emerging photocatalyst, has been successfully applied to synthetic chemistry in recent years and displayed remarkable catalytic ability under visible light. However, the molecular-level reaction mechanisms of uranyl photocatalysis are unclear. Here, we explore the mechanism of the stepwise benzylic C-H oxygenation of typical alkyl-substituted aromatics (i.e., toluene, ethylbenzene, and cumene) via uranyl photocatalysis using theoretical and experimental methods. Theoretical calculation results show that the most favorable reaction path for uranyl photocatalytic oxidation is as follows: first, hydrogen atom transfer (HAT) from the benzyl position to form a carbon radical ([R•]), then oxygen addition ([R•] + O2 → [ROO•]), then radical-radical combination ([ROO•] + [R•] → [ROOR] → 2[RO•]), and eventually [RO•] reduction to produce alcohols, of which 2° alcohol would further be oxidized to ketones and 1° would be stepwise-oxygenated to acids. The results of the designed verification experiments and the capture of reactive intermediates were consistent with those of theoretical calculations and the previously reported research that the active benzylic C-H would be stepwise-oxygenated in the presence of uranyl. This work deepens our understanding of the HAT mechanism of uranyl photocatalysis and provides important theoretical support for the relevant application of uranyl photocatalysts in organic transformation.

A Mechanism Underpinning the Bioenergetic Metabolism-Regulating Function of Gold Nanocatalysts.

Bioenergetic deficits are known to be significant contributors to neurodegenerative diseases. Nevertheless, identifying safe and effective means to address intracellular bioenergetic deficits remains a significant challenge. This work provides mechanistic insights into the energy metabolism-regulating function of colloidal Au nanocrystals, referred to as CNM-Au8, that are synthesized electrochemically in the absence of surface-capping organic ligands. When neurons are subjected to excitotoxic stressors or toxic peptides, treatment of neurons with CNM-Au8 results in dose-dependent neuronal survival and neurite network preservation across multiple neuronal subtypes. CNM-Au8 efficiently catalyzes the conversion of an energetic cofactor, nicotinamide adenine dinucleotide hydride (NADH), into its oxidized counterpart (NAD+ ), which promotes bioenergy production by regulating the intracellular level of adenosine triphosphate. Detailed kinetic measurements reveal that CNM-Au8-catalyzed NADH oxidation obeys Michaelis-Menten kinetics and exhibits pH-dependent kinetic profiles. Photoexcited charge carriers and photothermal effect, which result from optical excitations and decay of the plasmonic electron oscillations or the interband electronic transitions in CNM-Au8, are further harnessed as unique leverages to modulate reaction kinetics. As exemplified by this work, Au nanocrystals with deliberately tailored structures and surfactant-free clean surfaces hold great promise for developing next-generation therapeutic agents for neurodegenerative diseases.