Changes in short-chain fatty acids affect brain development in mice with early life antibiotic-induced dysbacteriosis.

Background: Early enteral nutrition and the gut microbiota profoundly influence neonatal brain development, with short-chain fatty acids (SCFAs) from the microbiota playing a pivotal role. Understanding the relationship between dysbiosis, SCFAs, and brain development is crucial. In this study, we investigated the impact of antibiotics on the concentration of SCFAs in neonatal feces. Additionally, we developed a model of gut dysbiosis in neonatal mice to examine the potential relationship between this imbalance, SCFAs production, and brain function development. Methods: We measured the SCFAs content in the feces of two groups of neonates, categorized based on whether antibiotics were used, and conducted the Neonatal Behavioral Neurological Assessment (NBNA) test on all neonates. Then we evaluated fecal SCFAs levels in neonates and neonatal mice post-antibiotic treatment using liquid chromatography-mass spectrometry (LC-MS) analysis. Morris water maze (MWM) tests assessed behavioral performance, and western blot analysis examined brain tissue-related proteins-neuron-specific enolase (NSE), ionized calcium binding adaptor molecule-1 (IBA1), and myelin basic proteins (MBP). Results: The use of antibiotics did not affect the NBNA scores of the two groups of neonates, but it did reduce the SCFAs content in their feces. Antibiotic administration induced gut dysbiosis in mice, resulting in decreased IBA1 and MBP expression. Interventions to restore gut microbiota ameliorated these effects. Mice with dysbiosis displayed cognitive deficits in the MWM test. SCFAs levels decreased during dysbiosis, and increased upon microbiota recovery. Conclusions: Neonatal dysbiosis affects the microbiota-gut-brain axis, impairing cognitive function and nervous system development. Reduced SCFAs may contribute significantly to these alterations.

Fe-Catalyzed Fluorosulfonylation of Alkenes via Sulfur Dioxide Insertion: Synthesis of Lactam-Functionalized Alkyl Sulfonyl Fluorides.

A novel Fe-catalyzed fluorosulfonylation of alkenes with Na2S2O4 and N-fluorobenzenesulfonimide (NFSI) for assembling various lactam-functionalized alkyl sulfonyl fluorides is disclosed. In this reaction, Na2S2O4 acts as both an SO2 source and a reductant. Furthermore, the resulting products can be efficiently transformed into valuable chemicals, including sulfonyl esters and sulfonamides, via the sulfur(VI) fluoride exchange (SuFEx) click reaction. Preliminary mechanistic studies suggest that the transformation proceeds through intramolecular radical cyclization, SO2 insertion, sulfite anion formation, and fluorination.

Comparison of postoperative analgesia effects between subcostal anterior quadratus lumborum block and transversus abdominis plane block in bariatric surgery: a prospective randomized controlled study.

BACKGROUND: Currently, the prevalence of obesity is on the rise annually. Bariatric surgery stands out as the most efficacious approach for addressing obesity. Obese patients are more prone to experience moderate to severe pain after surgery due to lower pain thresholds. Regional block, as an important component of multimodal analgesia in bariatric surgery, is crucial in reducing opioid consumption and alleviating postoperative pain in patients undergoing bariatric surgery. Transversus abdominis plane block (TAPB) has gained widespread utilization in bariatric surgery; however, its limitation of inadequate reduction of visceral pain in obese patients remains a significant concern. Therefore, it is imperative to explore new and more efficient strategies for analgesia. Quadratus lumborum block (QLB) has emerged as a popular nerve block in recent years, frequently utilized in conjunction with general anesthesia for abdominal surgery. In the cadaver study of QLB, it was confirmed that the dye level could reach up to T6 when using the subcostal anterior quadratus lumborum muscle approach, which could effectively reduce the incision pain and visceral pain of bariatric surgery patients during the perioperative period. However, there is currently a lack of research on the use of subcostal anterior QLB in patients undergoing bariatric surgery. Our study aims to investigate whether subcostal anterior QLB can provide superior perioperative analgesic efficacy for bariatric surgery under general anesthesia compared to TAPB, leading to reduced postoperative opioid consumption and a lower incidence of postoperative nausea and vomiting (PONV). METHODS AND DESIGN: This study is a prospective, randomized controlled trial aiming to recruit 66 patients undergoing bariatric surgery. The participants will be randomly allocated into two groups in a 1:1 ratio: subcostal anterior QLB group (n = 33) and TAPB group (n = 33). The study aims to investigate the efficacy of subcostal anterior QLB and TAPB in obese patients who are scheduled to undergo bariatric surgery. Our primary outcome is to observe the amount of opioids used in the two groups 24 h after operation. The secondary outcomes included VAS of pain during rest/activity after operation, the type and dose of additional analgesics, the occurrence and severity of PONV, the type and dose of additional antiemetic drugs, postoperative anesthesia care unit (PACU) time, time of first postoperative exhaust, time to first out of bed activity, time to first liquid diet and postoperative admission days. DISCUSSION: Opioid analgesics are prone to causing adverse reactions such as nausea, vomiting, and respiratory depression, especially in obese patients. Multimodal analgesia, including nerve block, can effectively reduce the dose of opioids and alleviate their adverse effects. Currently, TAPB is the most prevalent nerve block analgesia method for abdominal surgery. Recent studies have indicated that subcostal anterior QLB offers advantages over TAPB, including a wider block plane, faster onset, and longer maintenance time. It is not clear which of the two nerve block analgesia techniques is better for postoperative analgesia in patients undergoing bariatric surgery. Our objective in this investigation is to elucidate the superior method between TAPB and subcostal anterior QLB for postoperative pain management in bariatric surgery. TRIAL REGISTRATION: ChiCTR ChiCTR2300070556. Registered on 17 April 2023.

Cu(II)/Base Synergistic Promoted [2 + 1 + 3] Cyclization of Cyclic Ketones with α,ß-Unsaturated Aldehydes/Ketones and NH4I to Access Fused Pyridines.

Herein, a practical three-component [2 + 1 + 3] cyclization of various cyclic ketones with α,ß-unsaturated aldehydes/ketones and ammonium iodide (NH4I) to access highly functional fused pyridines has been developed. The features of this transformation include mild reaction conditions, readily available starting materials, and excellent chemoselectivity. This protocol is compatible with various functional groups, and the preliminary studies on the mechanism of the reaction are also provided.

Catalyst-Free, Zn-Mediated Decarboxylative Coupling of Chlorostibines to Access Alkylstibines with Stable C(sp3)-Sb Bonds.

Herein, decarboxylative C(sp3)-Sb coupling of aliphatic carboxylic acid derivatives with chlorostibines to access alkylstibines has been achieved. This catalyst-, ligand-, and base-free approach using zinc as a reductant affords various kinds of benzyldiarylstibines and other monoalkyldiarylstibines and tolerates various functional groups, including chlorine, bromine, hydroxyl, amide, sulfone, and cyano groups. The late-stage modification and the gram-scale experiments illustrate its potential application.

Seasonal response of soil microbial community structure and life history strategies to winter snow cover change in a temperate forest.

Snow cover provides a thermally stable and humid soil environment and thereby regulates soil microbial communities and biogeochemical cycling. A warmer world with large reductions in snow cover and earlier spring snowmelt may disrupt this stability and associated ecosystem functioning. Yet, little is known about the response of soil microbial communities to decreased snowpack and potential carry-over effects beyond the snow cover period. Herein, we tested this response by conducting a snowpack manipulation experiment (control, addition, and removal) in a temperate forest. Our results showed that fungi were more sensitive to changes in snowpack. Thicker snowpack increased the diversity of fungi, but had weak effects on the diversity of bacteria in winter. Thickening snow cover promoted the ratio of fungi to bacteria abundance across the year, and such relative increase in fungi abundance was largely driven by Basidiomycota phyla (Agaricomycetes class). Increased snowpack decreased soil nitrate concentration, and produced carry-over biogeochemical effects evidenced by increased summer ß-1,4-glucosidase and N-acetyl-ß-glucosaminidase activities. On a seasonal scale, microbial biomass peaked at both winter and summer; winter microbial community was fungi dominated, while bacteria dominated in summer. The abundances of bacterial phyla had greater seasonal variation than fungal phyla. Specifically, Actinobacteria had greater dominance in winter than in summer, while Acidobacteria, Proteobacteria, and Verrucomicrobia had greater abundance in summer than in winter. Microbial high yield-resource acquisition-stress tolerance life history strategies showed significant seasonal tradeoffs, i.e., resource acquisition and stress tolerance strategies dominated in summer, while high yield strategy dominated in winter. Overall, our findings underline that climate-induced reductions in snow cover can disrupt soil biogeochemical cycling also beyond the snow cover period due to shifts in soil microbial community structure and life history strategies.

Tuning Dynamic Structural Evolution of Bi24O31Cl10 for Enhancing Piezo-Photocatalytic Nitrogen Oxidation to Nitrate.

Direct nitrogen oxidation into nitrate under ambient conditions presents a promising strategy for harsh and multistep industrial processes. However, the dynamic structural evolution of active sites in surface reactions constitutes a highly intricate endeavor and remains in its nascent stage. Here, we constructed a Bi24O31Cl10 material with moiré superlattice structure (BCMS) for direct piezo-photocatalytic oxidation of nitrogen into nitrate. Excitingly, BCMS achieved excellent nitric acid production (15.44 mg g-1 h-1) under light and pressure conditions. Detailed experimental results show that the unique structure extracts the local strain tensor from the constricting Bi-Bi bond and Bi-O bond for internal structural reconstruction, which promotes the formation of electron and reactive molecule vortexes to facilitate charge transfer as well as N2 and O2 adsorption. Ultimately, these initiatives strengthen electron exchange between the superoxide radical and nitrogen as well as the binding strength of multiple intermediates, which swayingly adjusts the reaction path and energy barriers.

Protective effects of the secondary metabolites from Quercus salicina Blume against gentamicin-induced nephrotoxicity in zebrafish (Danio rerio) model.

To reveal the protective effect on the nephrotoxicity of Quercus salicina Blume(QS), a traditional medicine for the treatment of urolithiasis, the 50 % ethanol extract from the branches and leaves of QS was chemically studied by systematic solvent extraction and HPLC chromatography. Two phenolic acids and three flavonoids were identified by nuclear magnetic resonance spectroscopy, namely Ferulic acid (1), p-Hydroxycinnamic acid (2), Hesperidin (3), Formononetin (4), and Quercetin (5). At the same time, the gentamicin-induced nephrotoxicity of zebrafish was used as a model for the first time. The antioxidant activity of these derivatives with good antioxidant activity screened from free radical scavenging experiments in vitro (DPPH and ABTS) was evaluated in vivo, including protein levels (LPO, NO, GSH, and SOD), kidney injury factor (KIM-1), zebrafish kidney pathology and real-time PCR. The results showed that metabolites 1, 3, and 5 had strong antioxidant activity, and oxidative stress in renal tissue was significantly reduced; KIM-1, TNF-α, and IL-6 mRNA expression in a dose-dependent manner, which preliminarily revealed the protective effect of the secondary metabolites of QS on nephrotoxicity, and preliminarily discussed the structure-activity relationship. This study provides an experimental basis for further exploring the mechanism of QS in the kidney.

Anti-PD-L1 antibody retains antitumour effects while mitigating immunotherapy-related colitis in bladder cancer-bearing mice after CT-mediated intratumoral delivery.

Drug local delivery system that directly supply anti-cancer drugs to the tumor microenvironment (TME) results in excellent tumor control and minimizes side effects associated with the anti-cancer drugs. Immune checkpoint inhibitors (ICIs) have been the mainstay of cancer immunotherapy. However, the systemic administration of ICIs is accompanied by considerable immunotherapy-related toxicity. To explore whether an anti-PD-L1 antibody administered locally via a sustained-release gel-forming carrier retains its effective anticancer function while causing fewer colitis-like side effects, CT, a previously reported depot system, was used to locally deliver an anti-PD-L1 antibody together with curcumin to the TME in bladder cancer-bearing ulcerative colitis model mice. We showed that CT-mediated intratumoral coinjection of an anti-PD-L1 antibody and curcumin enabled sustained release of both the loaded anti-PD-L1 antibody and curcumin, which contributed to substantial anticancer effects with negligible side effects on the colons of the UC model mice. However, although the anti-PD-L1 antibody administered systemically synergized with the CT-mediated intratumoral delivery of curcumin in inhibiting tumour growth, colitis was significantly worsened by intraperitoneal administration of anti-PD-L1 antibody. These findings suggested that CT is a promising agent for the local delivery of anticancer drugs, as it can allow effective anticancer functions to be retained while sharply reducing the adverse side effects associated with the systemic administration of these drugs.

Local weak hydrogen bonds induced dipole-dipole interactions in polymer for enhancing photocatalytic oxidation.

Functionalizing organic polymers is an effective strategy for enhancing their photocatalytic performance. However, this approach is currently limited by specific motifs, complex preparation methods, and an unclear electron transfer mechanism. Here, we present a meticulously designed structure of perylene diimide connected with poly (barbituric acid trimer) through self-assembled hydrogen bonding. In particular, the local chemical environment of the two components is adjusted by hydrogen bond-induced dipole-dipole interactions, leading to the emergence of a significant inherent electric field. Additionally, the formation of hydrogen bonds provides electronic pathways that facilitate charge transfer from perylene to adjacent units. Moreover, the distinctive electronic structure enhances polarity transfer and improves activation and adsorption capabilities for reactive molecules. Ultimately, B-PDI exhibits outstanding oxidation rates for benzylamine to N-benzylidene-benzylamine (10.03 mmol g-1h-1) and selectivity (>99.99 %). Our work offers a widely popular approach for enhancing the photocatalytic activity of organic semiconductor materials by constructing hydrogen bonds in heterogeneous molecules.

Local polarization redistribution in ZnmIn2S3+m for the enhancing synergetic piezo-photocatalytic overall water splitting.

Piezo-photocatalytic water (deuterium oxide) decomposition is a promising strategy for realizing renewable energy, but the manipulation of the polar center remains a big challenge. This study uses a simple low-temperature hydrothermal process to successfully manufacture ZnmIn2Sm+3 (m = 1-3) (ZnIn2S4, Zn2In2S5 and Zn3In2S6). Incorporating both experimental and theoretical analyses, the structural contraction and local polarization of the Zn-S bond in Zn2In2S5 enhance the piezoelectric response and surface charge accumulation, which facilitate charge transfer and reduce the activation energy of water. Remarkably, Zn2In2S5 exhibits excellent piezoelectric photocatalytic total water splitting performance (H2/O2: 4284.72/1967.00 µmol g-1h-1), which is 1.77 times that of photocatalytic performance. Moreover, a significant enhancement in D2O splitting performance can be obtained for the optimized Zn2In2S5. Our work offers valuable insights into the disclosure of local polarization in catalysts for enhancing piezo-photocatalytic overall water splitting.

Analysis of influencing factors and construction of prediction model for postoperative nausea and vomiting in patients undergoing laparoscopic sleeve gastrectomy: a single-center retrospective cohort study.

BACKGROUND: With the increasing number of bariatric surgeries, the high incidence of postoperative nausea and vomiting (PONV) associated with this surgery has also gradually attracted attention. Among the common bariatric surgery methods, patients undergoing sleeve gastrectomy (SG) have the highest incidence of nausea and vomiting. The mechanism of occurrence of PONV is very complex. This study aims to explore the influencing factors of PONV in patients undergoing laparoscopic sleeve gastrectomy (LSG) and construct a nomogram prediction model based on these factors. METHODS: With the approval of the Ethics Committee, the electronic medical records of patients who underwent LSG from July 2022 to May 2023 were collected retrospectively. RESULTS: A total of 114 patients with complete medical records who underwent LSG from July 2022 to May 2023 were included in this study. Among them, 46 patients developed PONV, resulting in a PONV incidence rate of 40.4%. Multivariate logistic regression analysis revealed that female gender, the use of inhalation anesthesia, and operation time ≥ 120 min were risk factors for PONV in LSG. Additionally, the use of more than two kinds of antiemetic drugs was identified as a protective factor. Based on these factors, a nomogram model was constructed. CONCLUSION: PONV in patients undergoing LSG is related to gender, type of anesthesia, duration of surgery, and combination therapy with antiemetic drugs. The nomogram prediction model constructed in this study demonstrates high accuracy and discrimination in predicting the occurrence of PONV in patients undergoing LSG.

Effect of rmEGF combined with ELF-EMF on promoting wound healing in rats.

BACKGROUND: The process of wound healing is complex, and expediting it remains a challenge. The advantages of extremely low frequency electric and magnetic fields (ELF-EMF) are its non-invasive treatment, promotes healing and promotes myogenesis of C2C12 cells. Epidermal growth factor (EGF) is known to play a vital role in promoting wound healing, so a combination of ELF-EMF and EGF can have far-reaching significance. OBJECTIVE: To study the effect of recombinant murine epidermal growth factor (rmEGF) combined with ELF-EMF on wound healing. METHODS: Thirty-six rats were randomly divided into three groups: normal control group, EGF group, and ELF-EMF+EGF group, and a 20 mm × 20 mm dorsal wound was made. The wound healing rate of rats was calculated on the 3rd, 7th, 11th and 15th day. HE staining was used to observe the micro-morphological changes during the wound healing process. RESULTS: The wound healing rate of EGF+ELF-EMF group was better than other groups. On the 15th day of wound healing, the wounds of each group were completely healed. On the 3rd, 7th, 11th and 15th day of HE staining, the early inflammatory cell infiltration, the arrangement of fibroblasts and the number of new capillaries in the wounds of EGF+ELF-EMF group were better than those of the other groups. CONCLUSIONS: rmEGF combined with ELF-EMF significantly promotes wound healing in SD rats.

Exosomal Tenascin-C primes macrophage pyroptosis amplifying aberrant inflammation during sepsis-induced acute lung injury.

Sepsis-induced acute lung injury (ALI) is a serious complication of sepsis and the predominant cause of death. Exosomes released by lung tissue cells critically influence the progression of ALI during sepsis by modulating the inflammatory microenvironment. However, the molecular mechanisms by which exosome-mediated intercellular signaling exacerbates ALI in septic infection remain undefined. Our study found increased levels of exosomal Tenascin-C (TNC) in the plasma of both patients and mice with ALI, showing a strong association with disease progression. By integrating exosomal proteomics with transcriptome sequencing and experimental validation, we elucidated that LPS induce unresolved endoplasmic reticulum stress (ERs) in alveolar epithelial cells (AECs), ultimately leading to the release of exosomal TNC through the activation of PERK-eIF2α and the transcription factor CHOP. In the sepsis mouse model with TNC knockout, we noted a marked reduction in macrophage pyroptosis. Our detailed investigations found that exosomal TNC binds to TLR4 on macrophages, resulting in an augmented production of ROS, subsequent mitochondrial damage, activation of the NF-κB signaling pathway, and induction of DNA damage response. These interconnected events culminate in macrophage pyroptosis, thereby amplifying the release of inflammatory cytokines. Our findings demonstrate that exosomal Tenascin-C, released from AECs under unresolved ER stress, exacerbates acute lung injury by intensifying sepsis-associated inflammatory responses. This research provides new insights into the complex cellular interactions underlying sepsis-induced ALI.

Effect of ultrasound-guided lung recruitment to reduce pulmonary atelectasis after non-cardiac surgery under general anesthesia: a systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: At present, the application of bedside lung ultrasound is increasing gradually, but there is no relevant expert consensus or guidance for its evaluation in the field of perioperative anesthesia. Through this meta-analysis, we tried to determine the impact of ultrasound-guided lung recruitment maneuvers (LRM) on perioperative patients. METHODS: We searched PubMed, Cochrane Library database, Embase, and Clinical Trials gov for the randomized controlled trials (RCTs) published up to December 31, 2022. The primary outcome was the incidence of postoperative atelectasis. Secondary outcomes included lung ultrasound score (LUS) and LUS of each part. A total of 443 patients were examined in nine randomized controlled trials. RESULTS: The incidence of atelectasis after surgery in patients with ultrasound-guided LRM was less (RR 0.31; 95% CI 0.25-0.40; p < 0.05). The LUS (WMD - 6.24; 95% CI - 6.90-5.59; p < 0.05) and the LUS of each part (LUS in front lung region (WMD - 2.00; 95% CI - 2.49 to - 1.51; p < 0.05); LUS in lateral lung region (WMD - 2.50; 95% CI - 3.20 to - 1.80; p < 0.05); LUS in posterior lung region (WMD - 3.24; 95% CI - 4.23 to - 2.24; p < 0.05)) in patients with ultrasound-guided LRM were lower. CONCLUSION: Ultrasound-guided lung recruitment maneuvers have been shown to be a promising approach for improving perioperative lung ventilation by increasing aeration while mitigating the development of atelectasis. In comparison to non-ultrasound-guided methods, this technique has exhibited superior effects.

A nomogram model for predicting intramyocardial hemorrhage post-PCI based on SYNTAX score and clinical features.

OBJECTIVE: The aim of this study is to develop a nomogram model for predicting the occurrence of intramyocardial hemorrhage (IMH) in patients with Acute Myocardial Infarction (AMI) following Percutaneous Coronary Intervention (PCI). The model is constructed utilizing clinical data and the SYNTAX Score (SS), and its predictive value is thoroughly evaluated. METHODS: A retrospective study was conducted, including 216 patients with AMI who underwent Cardiac Magnetic Resonance (CMR) within a week post-PCI. Clinical data were collected for all patients, and their SS were calculated based on coronary angiography results. Based on the presence or absence of IMH as indicated by CMR, patients were categorized into two groups: the IMH group (109 patients) and the non-IMH group (107 patients). The patients were randomly divided in a 7:3 ratio into a training set (151 patients) and a validation set (65 patients). A nomogram model was constructed using univariate and multivariate logistic regression analyses. The predictive capability of the model was assessed using Receiver Operating Characteristic (ROC) curve analysis, comparing the predictive value based on the area under the ROC curve (AUC). RESULTS: In the training set, IMH post-PCI was observed in 78 AMI patients on CMR, while 73 did not show IMH. Variables with a significance level of P < 0.05 were screened using univariate logistic regression analysis. Twelve indicators were selected for multivariate logistic regression analysis: heart rate, diastolic blood pressure, ST segment elevation on electrocardiogram, culprit vessel, symptom onset to reperfusion time, C-reactive protein, aspartate aminotransferase, lactate dehydrogenase, creatine kinase, creatine kinase-MB, high-sensitivity troponin T (HS-TnT), and SYNTAX Score. Based on multivariate logistic regression results, two independent predictive factors were identified: HS-TnT (Odds Ratio [OR] = 1.61, 95% Confidence Interval [CI]: 1.21-2.25, P = 0.003) and SS (OR = 2.54, 95% CI: 1.42-4.90, P = 0.003). Consequently, a nomogram model was constructed based on these findings. The AUC of the nomogram model in the training set was 0.893 (95% CI: 0.840-0.946), and in the validation set, it was 0.910 (95% CI: 0.823-0.970). Good consistency and accuracy of the model were demonstrated by calibration and decision curve analysis. CONCLUSION: The nomogram model, constructed utilizing HS-TnT and SS, demonstrates accurate predictive capability for the risk of IMH post-PCI in patients with AMI. This model offers significant guidance and theoretical support for the clinical diagnosis and treatment of these patients.

Zn-Catalyzed Dehydroxylative Phosphorylation of Allylic Alcohols with P(III)-Nucleophiles.

A novel and efficient protocol for the synthesis of diarylallyl-functionalized phosphonates, phosphinates, and phosphine oxides through the zinc-catalyzed dehydroxylative phosphorylation of allylic alcohols with P(III)-nucleophiles via a Michaelis-Arbuzov-type rearrangement is reported. A broad range of allylic alcohols and P(III)-nucleophiles (P(OR)3, ArP(OR)2, and Ar2P(OR)) are well tolerated in this reaction, and the expected dehydroxylative phosphorylation products could be synthesized with good to excellent yields under the optimal reaction conditions. The reaction can be easily scaled up at a gram-synthesis level. Furthermore, through the step-by-step control experiments, kinetic study experiments, and 31P NMR tracking experiments, we acquired insights into the reaction and proposed the possible mechanism for this transformation.

Nickel-Catalyzed C(sp3)-Sb Coupling of Chlorostibines with Unactivated Alkyl Chlorides and In Vitro Anticancer Activity of Products.

In this study, we present a nickel-catalyzed reductive C(sp3)-Sb coupling of unactivated alkyl chlorides with chlorostibines. This approach is highly versatile, tolerating various functional groups such as acetal, alkene, nitrile, amine, ester, silyl ether, thioether, and various heterocyclic compounds. Notably, the late-stage modification of bioactive molecules and the satisfactory anticancer activity against cancerous MDA-MB-231 also demonstrate the potential application.

Trivalent Organostibines: Sb,N Ligands in Double N-Arylation of Primary Amines toward Functionalized Carbazoles.

A Sb,N ligand (L-Sb) for Pd-catalyzed double N-arylation of primary amines was developed. This trivalent ligand L-Sb, containing a 5,6,7,12-tetrahydrodibenzo[c,f][1,5]azastibocine skeleton and stable under air and moisture, could be synthesized facilely on a gram scale from chlorostibine (1) and cyclopentylmagnesium bromide. L-Sb showed excellent catalytic performance in Pd2(dba)3-catalyzed double N-arylation of 2,2'-dibromo-1,1'-biphenyl (2) with primary amines (3), affording functionalized carbazoles in good yields. This Pd2(dba)3/L-Sb-catalyzed double N-arylation, the first example of the application of trivalent organostibines as a ligand in N-arylation, featured the following advantages: small catalyst loading, wide functional group tolerance, good yields, and ease of gram-scale synthesis.

[Effects of Tomato Planting Years on Soil Physical and Chemical Properties and Microbial Communities].

Long-term continuous cropping of facility soils could influence soil properties; however, the differences in soil properties among different continuous cropping years are still not well understood. The objective of this study was to explore the effects of continuous cropping years of tomato on the physical and chemical properties and biological characteristics of facility soil. Conventional analysis, high-throughput sequencing, and other methods were used to examine the soil physicochemical properties, soil microbial community diversity, and enzyme activities in facility soil after continuous tomato cropping for 1-3 years, 5-7 years, and more than 10 years. As the continuous tomato cropping years increased, soil bulk density and pH decreased; soil maximal water holding capacity increased; and organic matter, total nitrogen, and total phosphorus accumulated. As continuous cropping years increased, the total salt and EC value decreased with continuous cropping for 5-7 years and increased from 5-7 years to more than 10 years continuous cropping and showed a trend of secondary soil salinization. There was a significant increase in alkaline phosphatase for 1-3 years to 5-7 years continuous tomato cropping. There were significant differences in fungal community abundance among different cropping years. The Simpson index and Shannon index of fungi showed a trend of increasing first and then decreasing with the extension of continuous cropping years and reached the maximum value at 5 years of continuous cropping. The Chao1 index decreased continuously following the cropping years. As continuous cropping years increased, Streptomyces became the dominant bacteria, and Aspergillus and Pseudaleuria became the dominant fungi. The key factors affected by continuous cropping years were available potassium and available nitrogen based on the redundancy analysis. The results of this study lay the foundation for future research on the influence of continuous cropping years on the health of facility soil.