Transient Absorption Spectroscopic Investigation of the Photocyclization-Deprotection Reaction of 3',5'-Dimethoxybenzoin Fluoride.

The 3',5'-dimethoxybenzoin (DMB) system has been widely investigated as a photoremovable protecting group (PRPG) for the elimination of various functional groups and has been applied in many fields. The photolysis of DMB fluoride leads to a highly efficient photocyclization-deprotection reaction, resulting in a high yield of 3',5'-dimethoxybenzofuran (DMBF) in a MeCN solution, while there is a competitive reaction that produces DMB in an aqueous solution. The yield of DMB increased as the volume ratio of water increased. To understand the solvent effect of the photolysis of selected DMB-based compounds, a combination of femtosecond to nanosecond transient absorption spectroscopies (fs-TA and ns-TA), nanosecond time-resolved resonance Raman spectroscopy (ns-TR3) and quantum chemical calculation was employed to study the photophysical and photochemical reaction mechanisms of DMB fluoride in different solutions. Facilitated by the bichromophoric nature of DMB fluoride with electron-donating and -withdrawing chromophores, the cyclized intermediates could be found in a pure MeCN solution. The deprotection of a cyclic biradical intermediate results in the simultaneous formation of DMBF and a cyclic cation species. On the other hand, in aqueous solution, fs-TA experiments revealed that α-keto cations could be observed after excitation directly, which could easily produce the DMB through the addition of a hydroxyl within 8.7 ps. This work provides comprehensive photo-deactivation mechanisms of DMB fluoride in MeCN and aqueous conditions and provides critical insights regarding the biomedical application of DMB-based PRPG compounds.

Construction and application of the conditionally essential gene knockdown library in Klebsiella pneumoniae to screen potential antimicrobial targets and virulence genes via Mobile-CRISPRi-seq.

Klebsiella pneumoniae is a ubiquitous human pathogen, and its clinical treatment faces two major challenges: multidrug resistance and the pathogenesis of hypervirulent K. pneumoniae. The discovery and study of conditionally essential (CE) genes that can function as potential antimicrobial targets has always been a research concern due to their restriction in the development of novel antibiotics. However, the lack of essential functional genomic data has hampered the study of the mechanisms of essential genes related to antimicrobial susceptibility. In this study, we developed a pooled CE genes mobile clustered regularly interspaced short palindromic repeat (CRISPR) interference screening method (Mobile-CRISPRi-seq) for K. pneumoniae to identify genes that play critical roles in antimicrobial fitness in vitro and host immunity in vivo. Targeting 870 predicted CE genes in K. pneumoniae, Mobile-CRISPRi-seq uncovered the depletion of tetrahydrofolate synthesis pathway genes folB and folP under trimethoprim pressure. Our screening also identified genes waaE and fldA related to polymyxin and ß-lactam susceptibility by applying a screening strategy based on Mobile-CRISPRi-seq and comparative genomics. Furthermore, using a mouse infection model and Mobile-CRISPRi-seq, multiple virulence genes were identified, and among these genes, pal, yciS, and ribB were demonstrated to contribute to the pathogenesis of K. pneumoniae. This study provides a simple, rapid, and effective platform for screening potential antimicrobial targets and virulence genes in K. pneumoniae, and this broadly applicable system can be expanded for high-throughput functional gene study in multiple pathogenic bacteria, especially in gram-negative bacteria. IMPORTANCE The discovery and investigation of conditionally essential (CE) genes that can function as potential antimicrobial targets has always been a research concern because of the restriction of antimicrobial targets in the development of novel antibiotics. In this study, we developed a pooled CE gene-wide mobile clustered regularly interspaced short palindromic repeat (CRISPR) interference sequencing (Mobile-CRISPRi-seq) strategy in Klebsiella pneumoniae to identify genes that play critical roles in the fitness of antimicrobials in vitro and host immunity in vivo. The data suggest a robust tool to screen for loss-of-function phenotypes in a pooled gene knockdown library in K. pneumoniae, and Mobile-CRISPRi-seq may be expanded to multiple bacteria for screening and identification of genes with crucial roles in the fitness of antimicrobials and hosts.

Efficacy and safety of PD-1 inhibitor alone or combined with chemotherapy in patients with relapsed or refractory extranodal natural Killer/T cell lymphoma: A retrospective study.

Extranodal natural killer/T cell lymphoma (ENKTL) patients typically face a grim prognosis after relapse or progression following asparaginase-based chemotherapy. Currently, programmed cell death protein-1 (PD-1) immune checkpoint blockade has shown promising efficacy as an optimal regimen for relapsed or refractory ENKTL (rrENKTL) patients. This study retrospectively investigated the efficacy, safety, and factors influencing the survival of 26 rrENKTL patients who underwent monoclonal antibody treatment using PD-1 (Sintilimab or Camrelizumab) alone or combined with chemotherapy from January 2018 to February 2022. The disease control rate was 73.1%, and the objective response rate was 50.0%. 15.4% of the patients achieved complete remission, and 34.6% achieved partial remission (PR). After a median follow-up of 12 (range 3-47) months, the median progression-free survival (PFS) and overall survival (OS) were 6.5 and 13.3 months. The 1-year PFS and OS rate were 23.1% and 53.8%. 96.2% of patients experienced at least one adverse event and 26.9% experienced grade 1-2 immune-related adverse events. PD-1 inhibitor improved rrENKTL patient survival, and the AEs were controlled. We also observed that the prognostic index for NK cell lymphoma including Epstein-Barr virus (EBV) (PINK-E) and the nomogram-revised risk indexz for ENKTL patients could help identify a potentially unfavorable prognosis in this era of immunotherapy. More attention should be paid to the presence of EBV after anti-PD-1 immunotherapy, as it more accurately indicates a poor prognosis.

A photoenhanced oxidation of amino acids and the cross-linking of lysozyme mediated by tetrazolium salts.

Tetrazolium salts (TZs) are pervasively utilized as precursors in the dye industry, colorimetric probes in enzyme assays and for exploring nanomaterial toxicity, but its own toxicity is not investigated enough so far. Using femtosecond transient absorption spectroscopy, nanosecond pulse radiolysis (ns-PRL), western blotting and UV-vis absorption spectroscopy, here we characterized a neutral tetrazolinyl radical (with the same maximum absorption at 420 nm and different lifetimes of 5.0 and 9.0 µs for two selected TZs), the key intermediate of TZs reduction, and noticed TZs-formazan production under UV light irradiation accompanied by 41% increase in the cross-linking of lysozyme (Lyso, model protein) compared to TZs-free sample, which uncovered the photoenhanced oxidation of TZs towards Lyso. The ns-PRL in a reductive atmosphere simulated the electron/proton donors of amino acid residues in Lyso upon photoexcitation and revealed the reduction mechanism of TZs, as that first followed one-electron-transfer and then probably proton-coupled electron transfer. This is the first time to report on the photoenhanced oxidation mechanism of TZs, which would provide new insights into the applications of TZs in cell biology, "click" chemistry and nanotoxicology.

Beyond the virus: a first look at coronavirus-themed Android malware.

As the COVID-19 pandemic emerged in early 2020, a number of malicious actors have started capitalizing the topic. Although a few media reports mentioned the existence of coronavirus-themed mobile malware, the research community lacks the understanding of the landscape of the coronavirus-themed mobile malware. In this paper, we present the first systematic study of coronavirus-themed Android malware. We first make efforts to create a daily growing COVID-19 themed mobile app dataset, which contains 4,322 COVID-19 themed apk samples (2,500 unique apps) and 611 potential malware samples (370 unique malicious apps) by the time of mid-November, 2020. We then present an analysis of them from multiple perspectives including trends and statistics, installation methods, malicious behaviors and malicious actors behind them. We observe that the COVID-19 themed apps as well as malicious ones began to flourish almost as soon as the pandemic broke out worldwide. Most malicious apps are camouflaged as benign apps using the same app identifiers (e.g., app name, package name and app icon). Their main purposes are either stealing users' private information or making profit by using tricks like phishing and extortion. Furthermore, only a quarter of the COVID-19 malware creators are habitual developers who have been active for a long time, while 75% of them are newcomers in this pandemic. The malicious developers are mainly located in the US, mostly targeting countries including English-speaking countries, China, Arabic countries and Europe. To facilitate future research, we have publicly released all the well-labelled COVID-19 themed apps (and malware) to the research community. Till now, over 30 research institutes around the world have requested our dataset for COVID-19 themed research.

Role of MMP-9 in epithelial-mesenchymal transition of thyroid cancer.

BACKGROUND: The purpose of this study is to explore the role and mechanism of MMP-9 in the EMT process of thyroid cancer (TC), so as to provide a basis for clinical exploration of invasion and metastasis process of TC, looking for biological markers of tumor metastasis and molecular intervention therapy. METHODS: Western blot and RT-PCR were employed to detect the expression of MMP-9 in human normal thyroid cell line HT-ori3 and human TC cell lines IHH-4 (PTC), FTC-133, and 8505C. Expression levels of EMT-related markers: epithelial cell marker E-cadherin and stromal cell marker Vimentin in TGF-1-induced TC cell lines were detected by Western blot and RT-PCR, respectively. The effects of MMP-9 downregulation on cell invasion and metastasis were investigated by wound-healing assay and cell invasion experiment. RESULTS: The protein and mRNA expression levels of MMP-9 in TC cell lines were increased compared with the human normal thyroid cell line HT-ori3. When TGF-ß1 was added, the expression of EMT and Vimentin increased while the expression of E-cadherin decreased. Compared with the control group, the TC cells stably transfected with MMP-9 shRNA showed inhibited EMT, decreased Vimentin expression, and increased E-cadherin expression. The induction of TGF-ß1 did not promote the occurrence of EMT in TC cells which were stably transformed with MMP-9 shRNA. The addition of TGF-ß1 to TC cells increased the ability of the cells to migrate and invade. Compared with the control group, the migration and invasion ability of TC cells stably transfected with MMP-9 shRNA was significantly reduced, and the induction of TGF-ß1 could not restore the migration and invasion ability of cells without MMP-9. CONCLUSIONS: In conclusion, we found that MMP-9 can be used as a biomarker for TC, which can promote the EMT process of TGF-ß1 induced TC, and thus affecting the cell migration and invasion ability.

Photochemical α-Cleavage Reaction of 3',5'-Dimethoxybenzoin: A Combined Time-Resolved Spectroscopy and Computational Chemistry Study.

Benzoin is one of the most commonly used photoinitiators to induce free radical polymerization. Here, improved benzoin properties could be accomplished by the introduction of two methoxy substituents, leading to the formation of 3',5'-dimethoxybenzoin (DMB) which has a higher photo-cleavage quantum yield (0.54) than benzoin (0.35). To elucidate the underlying reaction mechanisms of DMB and obtain direct information of the transient species involved, femtosecond transient absorption (fs-TA) and nanosecond transient absorption (ns-TA) spectroscopic experiments in conjunction with density functional theory/time-dependent density functional theory (DFT/TD-DFT) calculations were performed. It was found that the photo-induced α-cleavage (Norrish Type I reaction) of DMB occurred from the nπ* triplet state after a rapid intersystem crossing (ISC) process (7.6 ps), leading to the generation of phenyl radicals on the picosecond time scale. Compared with Benzoin, DMB possesses two methoxy groups which are able to stabilize the alcohol radical and thus result in a stronger driving force for cleavage and a higher quantum yield of photodissociation. Two stable conformations (cis-DMB and trans-DMB) at ground state were found via DFT calculations. The influence of the intramolecular hydrogen bond on the α-cleavage of DMB was elaborated.

Upregulated circular RNA circ_0007534 indicates an unfavorable prognosis in pancreatic ductal adenocarcinoma and regulates cell proliferation, apoptosis, and invasion by sponging miR-625 and miR-892b.

Circular RNAs (circRNAs) have been regarded as critical regulators of human diseases and biological markers in some types of malignancies, including pancreatic ductal adenocarcinoma (PDAC). Recently, circ_0007534 has been identified as a novel cancer-related circRNA. Nevertheless, its clinical relevance, functional roles, and mechanism have not been studied in PDAC. In the current study, real-time quantitative polymerase chain reaction (RT-qPCR) was used to detect the expression of circ_0007534 in 60-paired PDAC tissue samples and different cell lines. Loss-of-function and gain-of-function assays were performed to detect cell proliferation, apoptosis, and metastatic properties affected by circ_0007534. An animal study was also carried out. The luciferase reporter assay was performed to uncover the underlying mechanism of circ_0007534. As a result, circ_0007534 was overexpressed not only in PDAC tissues but also in a panel of PDAC cell lines, and this overexpression is closely associated with advanced tumor stage and positive lymph node invasion. In addition, circ_0007534 may be regarded as an independent prognostic factor for patients with PDAC. For the part of functional assays, circ_0007534 significantly increased cell proliferation, migratory, and invasive potential of PDAC cells. Circ_0007534 could inhibit cell apoptosis partly via a Bcl-2/caspase-3 pathway. The xenograft study further confirmed the cell growth promoting the role of circ_0007534. Mechanistically, miR-625 and miR-892b were sponged by circ_0007534. The oncogenic functions of circ_0007534 is partly dependent on its regulation of miR-625 and miR-892b. In conclusion, our study illuminates a novel circRNA that confers an oncogenic function in PDAC.

Long non-coding RNA LOXL1-AS1 acts as a ceRNA for miR-324-3p to contribute to cholangiocarcinoma progression via modulation of ATP-binding cassette transporter A1.

Accumulating evidence has appreciated long non-coding RNAs (lncRNAs) as novel prognostic markers and therapeutic targets in malignant carcinomas. Here, we aim to investigate the value of a novel cancer-related lncRNA, LOXL1-AS1, in cholangiocarcinoma (CCA). LOXL1-AS1 was found overexpressed in CCA tissues screened by high-throughput sequencing technology. Upregulation of LOXL1-AS1 was identified by TCGA database and qRT-PCR analysis. Additionally, upregulation of LOXL1-AS1 was associated with lymph node invasion, advanced TNM stages and unfavorable prognosis. Loss-of-function and gain-of-function experiments were conducted and validated that LOXL1-AS1 could facilitate cell proliferation, migration and invasion and attenuate cell apoptosis. Moreover, luciferase reporter and rescue assays indicated that LOXL1-AS1 functioned as a ceRNA to elevate ATP-binding cassette transporter A1 (ABCA1) level by sponging miR-324-3p and exhibited the malignant phenotypes of CCA cells, thereby playing an oncogenic role in CCA. Taken together, this study reveals that LOXL1-AS1 might act as a potential biomarker and therapeutic target for CCA clinical application.

Time-Resolved Spectroscopic and Density Functional Theory Investigation of the Photogeneration of a Bifunctional Quinone Methide in Neutral and Basic Aqueous Solutions.

Binol quinone methides (BQMs) can be generated from 1,1'-(2,2'-dihydroxy-1,1'-binaphthyl-6,6'-diyl)bis(N,N,N-trimethylmethanamiuium) bromide (BQMP-b) in a 1:1 MeCN:H2O mixed solution via a ground state intramolecular proton transfer (GSIPT), as mentioned in our previously reported studies. Here, the photoreaction of BQMP-b in neutral and basic aqueous solution (pH = 7, 10, 12) was investigated to explore the possible mechanisms and the key intermediates produced in the process of the photoreaction and to examine whether they are different from those in a neutral mild-mixed MeCN:H2O solution. The studies were conducted using femtosecond transient absorption (fs-TA), nanosecond transient absorption (ns-TA), and nanosecond time-resolved resonance Raman spectroscopy (ns-TR³) in conjunction with results from density functional theory (DFT) computations. The results showed that BQMP-b was deprotonated initially and produced BQMs species more effectively through an E1bc elimination reaction in a strong basic aqueous condition (pH = 12), which differed from the reaction pathway that took place in the solution with pH = 7 or 10. A related single naphthol ring molecule 1-(6-hydroxynaphthalen-2-yl)-N,N,N-trimethylmethanaminium bromide (QMP-b) that did not contain a second naphthol ring was also investigated. The related reaction mechanisms are elucidated in this work, and it is briefly discussed how the mechanisms vary as a function of aqueous solution pH conditions.

Circulating Tumor Cells and Tumor Stem Cells Detection in the Peripheral Blood Mononuclear Cells of Breast Cancer.

BACKGROUND: Our aim was to retrospectively analyze the relationships between circulating tumor cells (CTCs) and the development of breast cancer, for elucidating the role of CTCs in breast cancer. METHODS: A total of 107 female patients with primary breast cancer and 48 matched healthy female volunteers were recruited. After blood collection, isolation of peripheral blood mononuclear cells (PBMC) was performed followed by the detection of cytokeratin 19 positive (CK19(+) ) and CD44(+) /CD24(-/low) cells, as well as estrogen receptor (ER), progesterone, and CerbB2. Data were analyzed with the SPSS 20.0 software. RESULTS: None of the 48 volunteers were detected with CK19(+) cells in their PBMC, while in 77 patients, 72% of 107 female patients with primary breast cancer, the CK19(+) cells were detected. CK19(+) could also be detected among patients in each grouping by different clinical staging and lymph node metastasis, with statistical differences (all P < 0.05). Further, among the 83 CK19(+) specimens, 32 were also detected with CD44(+) /CD24(-/low) cells. Comparisons of CK19(+) and CD44(+) /CD24(-/low) cells in patients with different clinical features (ER positive vs. ER negative, C-erbB2 positive vs. C-erbB2 negative) and molecular subtypes (triple-negative breast cancer, ER positive, and C-erbB2 positive) showed no obvious difference (all P > 0.05). CONCLUSIONS: Both CTCs and tumor stem cells (TSCs) could be detected in the PBMC of breast cancer patients; besides, positive expression rate of CTCs might be obviously associated with the clinical stage and metastasis. Positive relationship of TSCs and the clinical stage of breast cancer was also proved in this study.

Highly sensitive determination of reduced glutathione based on a cobalt nanoparticle implanted-modified indium tin oxide electrode.

Cobalt nanoparticle modified indium tin oxide (CoNP/ITO) electrodes fabricated by ion implantation were applied for the detection of reduced glutathione (GSH). The CoNP/ITO electrode was characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) detector and X-ray photoelectron spectroscopy (XPS). The assay performance with regard to GSH were evaluated by cyclic voltammetry (CV) and chronoamperometry (I-t). The proposed sensor exhibited a much higher electrocatalytic activity toward the oxidation of GSH than the bare ITO electrode, with a detection limit of 5 nM. The CoNP/ITO electrode showed enhanced electrocatalytic properties, high sensitivity, good long-term stability and reproducibility as well as a rapid response to detect GSH. In addition, the CoNP/ITO electrode was also used to analyse the GSH concentration in eye drop samples, and the results were in good agreement with the labelled values.

Increased platelet-CD8+ T-cell aggregates displaying high activation, exhaustion, and tendency to death correlate with disease progression in people with HIV-1.

Platelets engage in HIV-1 infection by interacting with immune cells, which has been realized broadly. However, the potential interaction between platelets and CD8+ T cells remains unidentified. Here, treatment-naive individuals with HIV-1, complete immunological responders to antiretroviral therapy, and healthy controls were enrolled. First, we found that treatment-naive individuals with HIV-1 had low platelet numbers and high CD8+ T-cell counts when compared with complete immunological responders to antiretroviral therapy and healthy controls, leading to a low platelet/CD8+ T-cell ratio in peripheral blood, which could effectively differentiate the status of HIV-1 infection. Moreover, cytokines that may have been derived from platelets were higher in the plasma of people with HIV-1 despite viral suppression. Furthermore, we demonstrated that platelet-CD8+ T-cell aggregates were elevated in treatment-naive individuals with HIV-1, which positively correlated with HIV-1 viral load but negatively correlated with CD4+ T-cell count and CD4/CD8 ratio. Finally, we revealed that platelet-CD8+ T-cell aggregates correlate with enhanced activation/exhaustion and pyroptosis/apoptosis compared with free CD8+ T cells. Moreover, platelet-induced caspase 1 activation of CD8+ T cells correlated with IL-1ß and IL-18 plasma levels. In brief, we reveal the importance of platelets in HIV-1 infection, which might secrete more cytokines and mediate CD8+ T-cell phenotypic characteristics by forming platelet-CD8+ T-cell aggregates, which are related to poor prognosis.

Deep Amplicon Sequencing Reveals Culture Selection of Mycobacterium Tuberculosis by Clinical Samples.

The commonly-used drug susceptibility testing (DST) relies on bacterial culture and faces shortcomings such as long turnaround time and clone/subclone selection. We developed a targeted deep amplification sequencing (DAS) method directly applied to clinical specimens. In this DAS panel, we examined 941 drug-resistant mutations associated with 20 anti-tuberculosis drugs with an initial amount of 4 pg DNA and reduced clinical testing time from 20 days to two days. A prospective study was conducted using 115 clinical specimens mainly with Xpert® Mycobacterium tuberculosis/rifampicin (Xpert MTB/RIF) assay positive to evaluate drug-resistant mutation detection. DAS was performed on culture-free specimens, while culture-dependent isolates were used for phenotypic DST, DAS, and whole-genome sequencing (WGS). For in silico molecular DST, our result based on DAS panel revealed the similar accuracy to three published reports based on WGS. For 82 isolates, application of DAS showed better sensitivity (93.03% vs. 92.16%), specificity (96.10% vs. 95.02%), and accuracy (91.33% vs. 90.62%) than Mykrobe software using WGS. Compared to culture-dependent WGS, culture-free DAS provides a full picture of sequence variation at population level, exhibiting in detail the gain-and-loss variants caused by bacterial culture. Our study performs a systematic verification of the advantages of DAS in clinical applications and comprehensively illustrates the discrepancy in Mycobacterium tuberculosis before and after culture.

Cooperative Game-Based Approximate Optimal Control of Modular Robot Manipulators for Human-Robot Collaboration.

Major challenges of controlling human-robot collaboration (HRC)-oriented modular robot manipulators (MRMs) include the estimation of human motion intention while cooperating with a robot and performance optimization. This article proposes a cooperative game-based approximate optimal control method of MRMs for HRC tasks. A harmonic drive compliance model-based human motion intention estimation method is developed using robot position measurements only, which forms the basis of the MRM dynamic model. Based on the cooperative differential game strategy, the optimal control problem of HRC-oriented MRM systems is transformed into a cooperative game problem of multiple subsystems. By taking advantage of the adaptive dynamic programming (ADP) algorithm, a joint cost function identifier is developed via the critic neural networks, which is implemented for solving the parametric Hamilton-Jacobi-Bellman (HJB) equation and Pareto optimal solutions. The trajectory tracking error under the HRC task of the closed-loop MRM system is proved to be ultimately uniformly bounded (UUB) by the Lyapunov theory. Finally, experiment results are presented, which reveal the advantage of the proposed method.

Identification and validation of a pyroptosis-related signature in identifying active tuberculosis via a deep learning algorithm.

Introduction: Active tuberculosis (ATB), instigated by Mycobacterium tuberculosis (M.tb), rises as a primary instigator of morbidity and mortality within the realm of infectious illnesses. A significant portion of M.tb infections maintain an asymptomatic nature, recognizably termed as latent tuberculosis infections (LTBI). The complexities inherent to its diagnosis significantly hamper the initiatives aimed at its control and eventual eradication. Methodology: Utilizing the Gene Expression Omnibus (GEO), we procured two dedicated microarray datasets, labeled GSE39940 and GSE37250. The technique of weighted correlation network analysis was employed to discern the co-expression modules from the differentially expressed genes derived from the first dataset, GSE39940. Consequently, a pyroptosis-related module was garnered, facilitating the identification of a pyroptosis-related signature (PRS) diagnostic model through the application of a neural network algorithm. With the aid of Single Sample Gene Set Enrichment Analysis (ssGSEA), we further examined the immune cells engaged in the pyroptosis process in the context of active ATB. Lastly, dataset GSE37250 played a crucial role as a validating cohort, aimed at evaluating the diagnostic prowess of our model. Results: In executing the Weighted Gene Co-expression Network Analysis (WGCNA), a total of nine discrete co-expression modules were lucidly elucidated. Module 1 demonstrated a potent correlation with pyroptosis. A predictive diagnostic paradigm comprising three pyroptosis-related signatures, specifically AIM2, CASP8, and NAIP, was devised accordingly. The established PRS model exhibited outstanding accuracy across both cohorts, with the area under the curve (AUC) being respectively articulated as 0.946 and 0.787. Conclusion: The present research succeeded in identifying the pyroptosis-related signature within the pathogenetic framework of ATB. Furthermore, we developed a diagnostic model which exuded a remarkable potential for efficient and accurate diagnosis.

Time-Resolved Spectroscopic Study of a Photoinduced Intramolecular Chloride Exchange Reaction of 3',5'-Dimethoxybenzoin Chloride.

Photoremovable protecting groups are of great importance due to their remote control over the liberation of diverse reactive species temporally and spatially, including biologically active compounds and functional groups. Here, an in-depth investigation on the heterolysis-solvolysis reaction mechanisms of a photoremovable protecting group, 3',5'-dimethoxybenzoin (DMB) chloride, has been accomplished. With the aid of transient absorption and time-resolved resonance Raman spectroscopies, the features of the intermediates that emerged from the photolysis process were directly observed. Elaborate optical and theoretical studies on DMB chloride have suggested a long-lived α-keto cation intermediate (0.9 ms) exists as a key intermediate, unlike the radical intermediates that are typically generated in such photocyclization reactions. After undergoing nucleophilic addition and isomerization, the intermediate species eventually leads to the formation of the final product(s).

Cortical thickness and intrinsic activity changes in middle-aged men with alcohol use disorder.

BACKGROUND: Previous studies reported the alterations of brain structure or function in people with alcohol use disorder (AUD). However, a multi-modal approach combining structural and functional studies is essential to understanding the neural mechanisms of AUD. Hence, we examined regional differences in cortical thickness (CT) and amplitude of low-frequency fluctuation (ALFF) in patients with AUD. METHODS: Thirty male patients with AUD and thirty age- and education-matched healthy male controls were recruited. High-resolution anatomical and resting-state functional MRI (rs-fMRI) data were collected, and the CT and ALFF were computed. RESULTS: Behaviorally, males with AUD showed a cognitive decline in multiple domains. Structurally, they presented prominent reductions in CT in the bilateral temporal, insular, precentral, and dorsolateral prefrontal gyri (p < 0.05, voxel-wise family-wise error [FWE]). Functionally, a significant decrease in ALFF in the bilateral temporal, dorsolateral prefrontal, insular, putamen, cerebellum, right precuneus, mid-cingulate, and precentral gyri were observed (p < 0.05, FWE). CONCLUSIONS: Our findings demonstrate the dual alterations of alcohol-related brain structure and function in male patients with AUD. These results may be useful in understanding the neural mechanisms in AUD.

Bi(â ¢) and Ce(â £) functionalized carbon nitride photocatalyst for antibiotic degradation: Synthesis, toxicity, and mechanism investigations.

Graphite-phase carbon nitride (g-C3N4) has shown great potential for antibiotic wastewater treatment due to its unique electronic structure and corresponding to visible light. In this study, a series of Bi/Ce/g-C3N4 photocatalysts with different doping amount were developed by direct calcination method for Rhodamine B and sulfamethoxazole photocatalytic degradation. The experiment result shows that the photocatalytic performance of Bi/Ce/g-C3N4 catalysts were better than that of single component samples. Under the optimal experimental conditions, the degradation rates of RhB (20 min) and SMX (120 min) by 3Bi/Ce/g-C3N4 reached 98.3% and 70.5%, respectively. The theoretical calculation results of DFT show that after Bi and Ce doping modification, the band-gap width of g-C3N4 is reduced to 1.215 eV and carrier migration rate is greatly improved. The enhanced photocatalytic activity was mainly attributed to the capture of electrons after doping modification, which inhibition of photogenerated carriers recombination and reduced the gap width. The cyclic treatment experiment of sulfamethoxazole showed that Bi/Ce/g-C3N4 catalysts had good stability. Ecosar evaluation and leaching toxicity test showed that Bi/Ce/g-C3N4 can be safely used for wastewater treatment. This study provides a perfect strategy for modifying g-C3N4 and a new way to improve the photocatalytic performance.

Exploring Solvent Effects on the Proton Transfer Processes of Selected Benzoxazole Derivatives by Femtosecond Time-Resolved Fluorescence and Transient Absorption Spectroscopies.

Excited-state intramolecular proton transfer (ESIPT) is of great importance due to the large Stokes shift emission that can be observed in some ESIPT molecules. Although steady-state spectroscopies have been employed to study the properties of some ESIPT molecules, their excited-state dynamics have not been examined directly with time-resolved spectroscopy methods yet for a number of systems. Here, an in-depth investigation of the solvent effects on the excited-state dynamics of two prototypical ESIPT molecules, 2-(2'-hydroxyphenyl)-benzoxazole (HBO) and 2-(2'-hydroxynaphthalenyl)-benzoxazole (NAP), have been accomplished by using femtosecond time-resolved fluorescence and transient absorption spectroscopies. Solvent effects affect the excited-state dynamics of HBO more significantly than that of NAP. Particularly in the presence of water, the photodynamics pathways of HBO are changed, while only small changes can be found in NAP. An ultrafast ESIPT process that occurs within our instrumental response is observed for HBO, and this is followed by an isomerization process in ACN solution. However, in aqueous solution, the obtained syn-keto* after ESIPT can be solvated by water in about 3.0 ps, and the isomerization process is totally inhibited for HBO. The mechanism of NAP is different from HBO and is determined to be a two-step excited-state proton transfer process. Upon photoexcitation, NAP is deprotonated first in the excited state to generate the anion*, which can transfer to the syn-keto* form followed by an isomerization process.