Highly Sensitive Poly-N-isopropylacrylamide Microgel-based Electrochemical Biosensor for the Detection of SARS-COV-2 Spike Protein.

Objective: Late 2019 witnessed the outbreak and widespread transmission of coronavirus disease 2019 (COVID-19), a new, highly contagious disease caused by novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Consequently, considerable attention has been paid to the development of new diagnostic tools for the early detection of SARS-CoV-2. Methods: In this study, a new poly-N-isopropylacrylamide microgel-based electrochemical sensor was explored to detect the SARS-CoV-2 spike protein (S protein) in human saliva. The microgel was composed of a copolymer of N-isopropylacrylamide and acrylic acid, and gold nanoparticles were encapsulated within the microgel through facile and economical fabrication. The electrochemical performance of the sensor was evaluated through differential pulse voltammetry. Results: Under optimal experimental conditions, the linear range of the sensor was 10 -13-10 -9 mg/mL, whereas the detection limit was 9.55 fg/mL. Furthermore, the S protein was instilled in artificial saliva as the infected human saliva model, and the sensing platform showed satisfactory detection capability. Conclusion: The sensing platform exhibited excellent specificity and sensitivity in detecting spike protein, indicating its potential application for the time-saving and inexpensive detection of SARS-CoV-2.

Intraoperative Enteral Nutrition Feeding in Free-Flap Healing after Reconstruction Surgery for Head and Neck Cancers.

OBJECTIVE: To investigate the beneficial outcomes of intraoperative enteral feeding in free-flap regeneration after extended head and neck cancer resection and flap reconstruction surgery. STUDY DESIGN: A pilot randomized, double-blind, placebo-controlled clinical trial. SETTING: Single tertiary care center. METHODS: Patients with advanced head and neck cancers requiring radical tumor resections and free-flap reconstruction were randomly assigned to receive intraoperative enteral nutrition feeding (100 kcal/100 mL at 10-20 mL/h) via a nasogastric tube during free-flap reconstruction (n = 28) or continue fasting (n = 28). The primary outcome was impaired free-flap regeneration that required surgical reintervention within 90 days after the operation. Participants were enrolled between April 2020 and January 2022; the 90-day follow-up ended in April 2022. RESULTS: The incidence of total or partial flap failure was similar between the 2 groups (14.2% or n = 4 in each group), but the rate of wound dehiscence or edge necrosis was significantly reduced in the feeding group (n = 6 vs 0 for fasting vs feeding; absolute risk reduction, 25.0% [95% confidence interval, 6.9-43.0]%; p = 0.022). Hospital stay length was shorter (p = 0.042) and hand grip strength was better preserved (p = 0.025) in the feeding group. Plasma concentrations of interleukin (IL)-6 and IL-8 after the operation increased significantly more in the fasting group. Perioperative adverse events did not differ between the 2 groups. CONCLUSION: Perioperative enteral feeding is a simple, safe, and effective approach to improve perioperative systemic catabolism and proinflammatory reactions, thereby enhancing early wound regeneration after major operations.

Insomniacs show greater prefrontal activation during verbal fluency task compared to non-insomniacs: a functional near-infrared spectroscopy investigation of depression in patients.

BACKGROUND: Previous studies have shown that insomnia affects human prefrontal function and that there are specific patterns of brain activation to counteract sleep and improve cognition. However, the effects of insomnia on the prefrontal cortex of MDD (major depressive disorder) patients and the patterns of activation to counteract sleep in MDD patients remain unclear. The aim of this study is to examine this using fNIRS (functional near-infrared spectroscopy). METHODS: Eighty depressed patients and 44 healthy controls were recruited for this study. fNIRS was used to assess changes in the concentration of oxygenated hemoglobin ([oxy-Hb]) in the prefrontal cortex of all participants during the VFT (verbal fluency test) and to record the number of words created to assess cognitive ability. The Pittsburgh Sleep Quality Index was used to assess sleep quality, and the Hamilton Rating Scale for Depression (24-item) and Hamilton Rating Scale for Anxiety (14-item) were used to assess the severity of depression and anxiety. RESULTS: When comparing patients, the healthy control group had significantly higher [oxy-Hb] values in the bilateral prefrontal cortex during VFT than the MDD group. In the MDD group, the [oxy-Hb] values in all brain regions except the right DLPFC were significantly higher in the group with insomnia than in the group without insomnia, but their VFT performance was significantly lower than in the group without insomnia and the healthy group. PSQI scores were positively correlated with [oxy-Hb] values in some left-brain regions, whereas HAMD and HAMA scores were not correlated with [oxy-Hb] values. CONCLUSION: The PFC was significantly less active during VFT in those with MDD than in healthy controls. All brain regions, except the right DLPFC, were significantly more active in MDD patients with insomnia than in those without insomnia, suggesting that sleep quality needs to be an important indicator in fNIRS screening. In addition, there was a positive correlation between the severity of insomnia in the left VLPFC and the level of activation, suggesting a role for the left brain region in the neurophysiology of overcoming sleepiness in MDD patients. these findings may provide new ideas for the treatment of MDD patients in the future. TRIAL REGISTRATION: Our experiment was registered in the China Clinical Trial Registry (registration number ChiCTR2200065622) on November 10.( The first patient was recruited in 10/11/2022.).

[Dynamic Changes in Antibiotic Resistance Genes During Biological Fermentation of Chicken Manure and Pig Manure].

Livestock manure is a major carrier that stores and transmits antibiotic resistance genes (ARGs). The aim of this study was to identify the crucial environmental factors that result in the change in relative abundance of ARGs and MGEs to explore effective methods to reduce the occurrence of ARGs. The abundance of ten ARGs and five MGEs were measured using real-time quantitative PCR with 0, 3, 7, 10, 14, 21, 28, 45, 60, and 75 d in CM and PM aerobic composting. The succession law of the bacterial community was analyzed using 16S rRNA high-throughput sequencing. Furthermore, the abundance of ARGs and MGEs was correlated with the properties (temperature, moisture content, pH, and DOC) of composting piles to identify the crucial factors affecting the variation in ARGs and MGEs. The results showed that the abundance of ARGs and MGEs in PM was higher than that in CM. Composting significantly reduced the relative abundance of nine ARGs and five MGEs. The removal ratios of three ARGs (tetM, tetT, and aacA) and four MGEs (ISEcp1, IS1216, IS613, and tnp614) in CM reached 99%. The removal ratios of nine ARGs[tetB(P), tetL, tetM, tetO, tetT, aacA, aadD,aphA3, and sat4] and four MGEs (ISEcp1, IS26, IS1216, and tnp614) reached 99% in PM. However, the abundance of the genes tetG, intI1, and IS6100 increased. Firmicutes and Actinobacteria were dominant in CM and PM during composting. Actinobacteria and Proteobacteria may have been the major host bacteria of tetG and intI1. The redundancy analysis showed that moisture and pH were the crucial factors that could influence the differences in the abundance of ARGs and MGEs. The composition and abundance of ARGs were driven by physicochemical properties, bacterial community, and MGEs. Composting could significantly reduce the abundance of ARGs in CM and PM, thus reducing the risk of ARGs being distributed via livestock manure application. However, some ARGs and MGEs remained in high abundance. Therefore, it is necessary to further optimize the composting process, improve the harmless treatment effect of livestock manure, and promote the safe agricultural use of organic fertilizers.

Iron-Catalyzed Coupling of Alkenes and Enones: Sakurai-Michael-type Conjugate Addition of Catalytic Allyliron Nucleophiles.

The iron-catalyzed coupling of alkenes and enones through allylic C(sp3)-H functionalization is reported. This redox-neutral process employs a cyclopentadienyliron(II) dicarbonyl catalyst and simple alkene substrates to generate catalytic allyliron intermediates for 1,4-addition to chalcones and other conjugated enones. The use of 2,4,6-collidine as the base and a combination of triisopropylsilyl triflate and LiNTf2 as Lewis acids was found to facilitate this transformation under mild, functional group-tolerant conditions. Both electronically unactivated alkenes as well as allylbenzene derivatives could be employed as pronucleophilic coupling partners, as could a range of enones bearing electronically varied substituents.

Synthesis of C4-Aminated Carbazoles and Their Derivatives via Pd/NBE Chemistry.

Carbazole, as one of the most important organic frameworks, has been used in optoelectronic materials and biochemistry. However, the synthesis of C4-substituted carbazole has always been an unsolved problem. This report describes the one-step synthesis of C4-aminated carbazoles and their derivatives through the series reaction of C-H amination and arylation. The substrate scope is wide. C4-Amino carbazoles substituted by C2, C6, C7, and C8 methyl groups, especially carbazole derivatives of fused rings, pyridine, and dibenzofuran, can be synthesized.

Designed Iron Catalysts for Allylic C-H Functionalization of Propylene and Simple Olefins.

Propylene gas is produced worldwide by steam cracking on million-metric-ton scale per year. It serves as a valuable starting material for π-bond functionalization but is rarely applied in transition metal-catalyzed allylic C-H functionalization for fine chemical synthesis. Herein, we report that a newly-developed cationic cyclopentadienyliron dicarbonyl complex allows for the conversion of propylene to its allylic C-C bond coupling products under catalytic conditions. This approach was also found applicable to the allylic functionalization of simple α-olefins with distinctive branched selectivity. Experimental and computational mechanistic studies supported the allylic deprotonation of the metal-coordinated alkene as the turnover-limiting step and led to insights into the multifaceted roles of the newly designed ligand in promoting allylic C-H functionalization with enhanced reactivity and stereoselectivity.

Using Deep Neural Network Approach for Multiple-Class Assessment of Digital Mammography.

According to the Health Promotion Administration in the Ministry of Health and Welfare statistics in Taiwan, over ten thousand women have breast cancer every year. Mammography is widely used to detect breast cancer. However, it is limited by the operator's technique, the cooperation of the subjects, and the subjective interpretation by the physician. It results in inconsistent identification. Therefore, this study explores the use of a deep neural network algorithm for the classification of mammography images. In the experimental design, a retrospective study was used to collect imaging data from actual clinical cases. The mammography images were collected and classified according to the breast image reporting and data-analyzing system (BI-RADS). In terms of model building, a fully convolutional dense connection network (FC-DCN) is used for the network backbone. All the images were obtained through image preprocessing, a data augmentation method, and transfer learning technology to build a mammography image classification model. The research results show the model's accuracy, sensitivity, and specificity were 86.37%, 100%, and 72.73%, respectively. Based on the FC-DCN model framework, it can effectively reduce the number of training parameters and successfully obtain a reasonable image classification model for mammography.

Discovery of specific catalytic activity toward IAA/FA by LaSABATHs based on genome-wide phylogenetic and enzymatic analysis of SABATH gene family from Larix kaempferi.

The SABATH methyltransferases catalyze methylation of small-molecule metabolites, which participate in plant growth, development and defense response. Given lack of genome-wide studies on gymnosperms SABATH family, the formation and functional differentiation mechanism of the Larix kaempferi SABATH gene family was systematically and exhaustively explored by analyzing gene sequence characteristics, phylogenetic relationship, expression pattern, and enzyme activities. Phylogenetic analysis showed that 247 SABATH genes from 14 land plants were divided into 4 clades, and lineage-specific gene duplication events were important factors that contributed to the evolution of the SABATH gene family in gymnosperms and angiosperms. Substrate specificity analysis of 18 Larix SABATH proteins showed that LaSABATHs could catalyze O-methylation of indole-3-acetic acid (IAA) and farnesic acid (FA), N-methylation of theobromine, and S-methylation of thiobenzoic acid. Furthermore, only LaSABATH2 and LaSABATH29 could catalyze O-methylation of FA, and only LaSABATH30 could catalyze O-methylation of IAA. Homology modeling and molecular docking studies showed the hydrogen bond formed between the His188 of LaSABATH30 and IAA and the noticeable hydrophobic IAA-binding pocket may be helpful for IAA methylation. In this study, identification of proteins with significant specific catalytic activity toward FA and IAA provided high-quality candidate genes for forest genetics and breeding.

Implication of Changes in the Imaging Measurements after Mechanically Aligned Total Knee Arthroplasty.

OBJECTIVE: Imaging measurements allow assessment of the mechanical alignment before and after total knee arthroplasty (TKA). The changes in radiographic parameters in each period of time within 1 year after TKA has been poorly understood. The purpose of this study was to examine the timing and causes of imaging changes in lower extremity force lines after total knee arthroplasty with mechanical alignment. METHODS: A total of 93 mechanically-aligned TKA were radiographically examined before, 3 days, 3 months, and 1 year after surgery. Radiographic parameters included hip-knee angle (HKA), lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), knee joint line orientation (KJLO), ankle joint line orientation (AJLO), the knee joint line relative to ankle joint line angle (KJLTA) and midpoints of the ankle distance (MAD). Paired t-test were used to analyze the changes of these imaging parameters, By establishing a simple tibial model, the time points of changes in the imaging parameters after TKA was determined, with an attempt to understand the post-TKA changes in these imaging parameters. RESULTS: Statistically significant differences were found between the preoperative data and the data measured 3 days after surgery in HKA, LDFA, MPTA, MAD, KJLTA, AJLO (P < 0.05) while KJLO exhibited no significant difference (P = 0.089). There existed significant differences between the data measured 3 days and the measurements taken 3 months after operation in HKA, MPTA, KJLTA, KJLO, AJLO (P < 0.05), whereas LDFA and MAD showed no significant difference (P > 0.05). Significant differences were revealed between the data measured 3 months and those collected 1 year after surgery in LDFA, MPTA, AJLO, KJLTA (P < 0.05) but HKA, KJLO, AJLO showed no significant differences (P > 0.05). The tibial model was made to look into the changes in postoperative imaging parameters. ΔMAD and postoperative AJLO were calculated to verify the model and hypothesis. CONCLUSIONS: Postoperative changes in radiographic parameters and tibial models showed that the lower extremities were in an unnatural state within 1 year after TKA. The changes in the lower extremities force line were the results of the gradual adaptation of the lower extremities to TKA and the lateral swing of the extremities (3°) after surgery. Imaging data 1 year after surgery should be taken into account in the explanation of post-TKA changes in lower limb force lines.

Development of a core outcome set in the clinical trials of traditional Chinese medicine for diabetic foot: A study protocol.

Background: Diabetic Foot (DF) is one of the most common complications of diabetes, and it is characterized by high morbidity, disability, lethality and low cure rate. Traditional Chinese medicine treatment has certain characteristics and advantages in diabetic foot. Due to selective reporting bias and heterogeneity of research results, on the one hand, relevant clinical studies are of low quality and poor practicability, and on the other hand, similar studies cannot be included in meta-analysis to form high-quality evidence-based evidence and evaluate the value of studies. Therefore, the development of a core set of outcomes (COS-TCM-DF) for traditional Chinese medicine for the treatment of diabetic foot is an important way to address these issues. Methods: The COS-TCM-DF project will refer to the developed COS methodology and the steps are divided into four stages: (1) a scoping review and analysis of enrolled research protocols to collect and analyze all existing outcomes that have been used in trials on the prevention or treatment of diabetic foot with Chinese Medicine; (2) qualitative interviews with Diabetic foot patient and attendants to Collect additional outcomes related to them; (3) Gather opinionest and obtain initial consensus from key stakeholders, including patients, clinicians, researchers, and pharmaceutical company staff, through a Delphi survey; (4) a consensus meeting was held to develop the final COS-TCM-DF. Discussion: Currently, there is no COS on measuring or monitoring diabetic foot with TCM in trials or clinical practice. The COS-TCM-DF will be developed to advance the synthesis of evidence regarding the prevention and treatment of diabetic foot in TCM and to promote the standardized and consistent application of results in future studies in this field. Trial registration: Registered with the Core Outcome Measures in Effectiveness Trials (COMET) database, December 2019 https://www.comet-initiative.org/Studies/Details/1553.

Analyses of adult transcriptomes from four different populations of the spongy moth, Lymantria dispar L., from China and the USA.

The spongy moth Lymantria dispar, formerly known as the gypsy moth, is a forest pest that occurs as two different biotypes: the European spongy moth (ESM), Lymantria dispar dispar, which is distributed in Europe and North America; and the Asian spongy moth (ASM), which consists of subspecies Lymantria dispar asiatica and Lymantria dispar japonica and is distributed in China, Russia, Korea, and Japan. The Asian biotype is classified as a quarantine pest by the U.S. Department of Agriculture because of the superior flight ability of adult females compared to females of the European biotype. To identify genes that potentially account for differences in female flight capability between the two biotypes, we assembled and compared transcriptional profiles of two North American populations of ESM and two Chinese populations of ASM, including samples of unmated female adults and females after mating and oviposition. Of 129,286 unigenes identified, 306 were up-regulated in ASM samples relative to ESM, including genes involved in egg production. In contrast, 2309 unigenes were down-regulated in ASM samples, including genes involved in energy production. Although a previous study found that ASM female flight was reduced after oviposition, a comparison of gene expression before and after mating and oviposition did not reveal any genes which were consistently up- or down-regulated in the two ASM populations.

Schisandra B, a representative lignan from Schisandra chinensis, improves cisplatin-induced toxicity: An in vitro study.

Schisandrin B (Scheme B) is the most abundant and active lignan monomer isolated from Schisandra chinensis. At present, most reports focus on its cardioprotective and hepatoprotective effects, however, the related reports on gastrointestinal protective effects are still limited. The study aims to evaluate the protective effect of Scheme B on cisplatin-induced rat intestinal crypt epithelial (IEC-6) cell injury and the possible molecular mechanisms. The results showed that Scheme B at 2.5, 5 and 10 µM could inhibit dose-dependently the reduction of cell activity induced by cisplatin exposure at 1 µM, decrease the levels of reactive oxygen species (ROS) and malondialdehyde (MDA), while increasing glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) to alleviate oxidative stress injury in IEC-6 cell lines. Meanwhile, Scheme B could relieve cisplatin-induced apoptosis by regulating PI3K/AKT and the downstream caspase signaling pathway. The results from flow cytometry analysis and mitochondrial membrane potential (MMP) staining also demonstrated the anti-apoptosis effect of Scheme B. Furthermore, Scheme B was found to reduce the inflammation associated with cell damage by evaluating the protein expressions of the nuclear factor-kappa B (NF-κB) signaling pathway. Importantly, Wnt/ß-catenin, as a functional signaling pathway that drives intestinal self-recovery, was also in part regulated by Scheme B. In conclusion, Scheme B might alleviate cisplatin-induced IEC-6 cell damage by inhibiting oxidative stress, apoptosis, inflammation, and repairing intestinal barrier function. The present research provides a strong evidence that Scheme B may be a useful modulator in cisplatin-induced intestinal toxicity.

Reduced Graphene Oxide Derived from Low-Grade Coal for High-Performance Flexible Supercapacitors with Ultrahigh Cyclability.

Preparation of reduced graphene oxide (RGO) from abundant and inexpensive low-grade coal is regarded as one of the most promising methods for utilizing this resource in a high-value and environmentally sustainable manner. As the main precursor for the fabrication of RGO, graphene oxide (GO) can be extracted from low-grade coal such as lignite, but its size is just in the range of tens to hundreds of nanometers, which limits its practical application. Herein, we demonstrate that large-size RGO sheets can be prepared in large quantities by the pretreatment of lignite using the high temperature-high pressure (HTHP) method. The RGO electrode after the reduction reaction by 50 mM NaBH4 at 105 °C features porosity and high conductivity, which can facilitate high electrochemical reaction efficiency. Thus, we also demonstrate the use of lignite-derived RGO for supercapacitor electrode materials with high performance. The lignite-derived RGO supercapacitor can deliver outstanding volumetric capacitance (30.6 F cm-3), high energy density (4.2 mW h cm-3), excellent flexibility (79.5% retention of the initial capacitance at 180° bending), and a long lifespan (112.3% retention of the initial capacitance after 20,000 cycles). It is believed that the proposed large-size RGO based on reasonable optimization of inferior lignite will offer a new prospect for next-generation energy storage applications.

Vinyl cation-mediated intramolecular hydroarylation of alkynes using pyridinium reagents.

Once considered to be exotic species of limited synthetic utility, vinyl cations have recently been shown to be highly versatile intermediates in a variety of processes. Here, we report a method for the synthesis of aryl-substituted benzocycloheptenes and -hexenes using the hydrotriflate salt of an electron-poor pyridine as a uniquely efficient proton source for a vinyl cation mediated Friedel-Crafts cyclization. The mild conditions made possible by this reagent allowed a range of simple and functionalized alkynes bearing pendant aryl groups to serve as suitable substrates for this scalable and convenient protocol.

IL-37 improves mice myocardial infarction via inhibiting YAP-NLRP3 signaling mediated macrophage programming.

OBJECTIVE: Myocardial infarction is the highest cause of cardiovascular death. Previous studies found that patients with myocardial infarction have elevated serum IL-37 and IL-37 treatment significantly alleviates adverse remodeling in myocardial infarction mice. However, the underlying mechanism of IL-37 in myocardial infarction is still unknown. Here we explored the underlying mechanism of IL-37 in attenuating myocardial infarction. METHODS: The myocardial infarction mice model was constructed by left anterior descending ligation and then submitted to recombinant IL-37 administration. The histology and cardiac function were detected by HE & Masson staining and echocardiography, respectively. The macrophage phenotypes were analyzed by flow cytometry and real-time PCR. The cytokines in serum and cell culture supernatant were determined by ELISA. In addition, THP-1 cells were used in vitro to investigate the underlying mechanisms. RESULTS: Infarcted mice showed increased inflammatory cell infiltration and impaired cardiac function. IL-37 treatment alleviated pro-inflammatory macrophage infiltration, tissue injury, and collagen deposition in hearts on day 3 and 7 after infarction in mice. In addition, IL-37 application modulated the balance between M1 and M2 macrophages in infarcted hearts. In vitro, THP-1 cell line polarization was also regulated by IL-37, companied by YAP phosphorylation and NLRP3 inactivation. Verteporfin, a YAP inhibitor, could abolish IL-37-induced NLRP3 inhibition and M2 macrophage polarization. CONCLUSION: Our results demonstrated that IL-37 achieves a favorable therapeutical function on myocardial infarction by modulating YAP-NLRP3 mediated macrophage programming, providing a promising drug for the treatment of myocardial infarction.

The Comparison between Mini-Subvastus Approach and Medial Parapatellar Approach in TKA: A Prospective Double-Blinded Randomized Controlled Trial.

OBJECTIVE: Minimal invasive approach has been increasingly used in total knee arthroplasty (TKA) and more is expected of early rehabilitation in terms of pain release and recovery of knee function. The approach type is one of the major factors that determines the early rehabilitation after TKA. The purpose of this study is to determine whether mini-subvastus approach (MSVA) is superior to the traditional medial parapatellar approach (MPA) in TKA. METHODS: From 2018 to 2019, a randomized double-blinded prospective study was conducted on 58 patients who underwent simultaneous bilateral TKA. The subjects included eight men and 50 women, with an average age of 65 years. One side was randomized using MSVA and the other side using MPA. Visual analog scale (VAS), operative duration, recovery time to straight leg raising (SLR), range of motion (ROM), HSS score, release rate of lateral retinaculum, satisfaction rate were recorded and compared. Paired-samples T test were used for quantitative data and chi-square test for qualitative data. RESULTS: There was no statistical difference in the ratio of left and right sides, preoperative ROM, VAS, HSS score, muscular strength of lower limbs, KL grade, operative order, and operative duration between the two groups. The average ROM (118.91 ± 8.21 vs. 107.60 ± 7.99, t = 14.320, p = 0.0000) and HSS score (72.03 ± 4.55 vs. 61.22 ± 4.36, t = 13.095, p = 0.0000) on POD 3, VAS in rest and motion on POD 1 and 3, the recovery time to SLR (1.17 ± 0.38 vs. 3.09 ± 0.76, t = 19.902, p = 0.0000), and the satisfaction rate on POD 1 (96.55% vs. 74.14%, χ2  = 9.9251, p = 0.0016) were superior in the MSVA group over MPA group. ROM in rest and motion and HSS score on POD 30 had no difference. The release rate of lateral retinaculum was less in the MSVA group than in the MPA group. The mean value of HKA, FFC, and FTC and the proportion of outliers did not differ significantly between the two groups. CONCLUSIONS: Compared with MPA, MSVA can make ROM of knee and SLR recover earlier, reduce postoperative pain after TKA, improve the early postoperative satisfaction and reduce the lateral release rate. MSVA can be used as a favorable measure in the concept of enhanced recovery after surgery (ERAS).

[Pollution Characteristics and Source Analysis of Atmospheric PM2.5-bound Polycyclic Aromatic Hydrocarbons in a Port Area].

In order to explore the pollution characteristics and potential sources of polycyclic aromatic hydrocarbons (PAHs) in the polluted air of a port area, PM2.5 samples (n=59) were collected from Qingdao Port for four seasons from August 2018 to May 2019. The seasonal variation and composition characteristics of PM2.5-bound PAHs were analyzed, the influence of meteorological factors on PAH concentrations was explored using correlation analysis, and the potential sources were analyzed using positive definite matrix factorization and potential source contribution function models. The results showed that the total mean concentration of PAHs was (8.11±12.31) ng·m-3, which was higher in autumn and winter than that in spring and summer. The seasonal molecular compositions of PAHs were similar, dominated by 4-5 ring PAHs (75.43%). Fluoranthene, benzo[e]pyrene, benzo[a]anthracene, phenanthrene, pyrene, and chrysene were the dominant species of PAHs in the study area, which are similar to the major compounds in ship exhaust. Correlation analysis showed that PAH concentrations were significantly negatively correlated with temperature and relative humidity and significantly positively correlated with atmospheric pressure and wind direction and had a poor correlation with wind speed. PMF analysis extracted six contribution factors, and the results indicated that Qingdao Port was mainly influenced by shipping emissions (28.83%), followed by vehicle emissions (20.49%), as well as crude oil volatilization (13.47%). Summer had the greatest impact on shipping emissions. The PSCF results suggested that Beijing-Tianjin-Hebei, Bohai Rim, and northern Shandong were the main source regions for long-range transport.

Enantioselective and Diastereodivergent Allylation of Propargylic C-H Bonds.

An iridium-catalyzed stereoselective coupling of allylic ethers and alkynes to generate 3,4-substituted 1,5-enynes is reported. Under optimized conditions, the coupling products are formed with excellent regio-, diastereo-, and enantioselectivities, and the protocol is functional group tolerant. Moreover, we report conditions that allow the reaction to proceed with complete reversal of diastereoselectivity. Mechanistic studies are consistent with an unprecedented dual role for the iridium catalyst, enabling the propargylic deprotonation of the alkyne through π-coordination, as well as the generation of a π-allyl species from the allylic ether starting material.

Impact of Sub-MIC Eugenol on Klebsiella pneumoniae Biofilm Formation via Upregulation of rcsB.

The Rcs phosphorelay system is present in many members of the Enterobacteriaceae. The aim of this study was to illustrate the possible mechanisms of eugenol on ultimate targets of Klebsiella pneumoniae (K. pneumoniae) Rcs phosphorelay, rcsB, and impact on biofilm formation. The minimum inhibitory concentration (MIC) of eugenol against K. pneumoniae KP1 and KP1 ΔrcsB strain was determined using the 2-fold micro-dilution method. Biofilm was measured by crystal violet staining. Transcriptome sequencing was performed to investigate sub-MIC eugenol on K. pneumoniae, and gene expression at mRNA level was analyzed by RT-qPCR. In vitro biofilm formation test and molecular docking were used to evaluate the effect of eugenol and to predict potential interactions with RcsB. MicroScale Thermophoresis (MST) was conducted for further validation. MIC of eugenol against K. pneumoniae KP1 and KP1 ΔrcsB strain was both 200 µg/ml. Transcriptome sequencing and RT-qPCR results indicated that rpmg, degP, rnpA, and dapD were downregulated, while rcsB, rcsD, rcsA, yiaG, and yiaD were upregulated in the eugenol-treated group. ΔrcsB exhibited a weakened biofilm formation capacity. Additional isopropyl-ß-d-thiogalactoside (IPTG) hinders biofilm formation, while sub-MIC eugenol could promote biofilm formation greatly. Docking analysis revealed that eugenol forms more hydrophobic bonds than hydrogen bonds. MST assay also showed a weak binding affinity between eugenol and RcsB. These results provide significant evidence that rcsB plays a key role in K. pneumoniae biofilm formation. Sub-MIC eugenol facilitates biofilm formation to a large extent instead of inhibiting it. Our findings reveal the potential risk of natural anti-biofilm ingredients at sub-MIC to treat drug-resistance bacteria.