Direct C-H Sulfuration: Synthesis of Disulfides, Dithiocarbamates, Xanthates, Thiocarbamates and Thiocarbonates

In light of the important biological activities and widespread applications of organic disulfides, dithiocarbamates, xanthates, thiocarbamates and thiocarbonates, the continual persuit of efficient methods for their synthesis remains crucial. Traditionally, the preparation of such compounds heavily relied on intricate multi-step syntheses and the use of highly prefunctionalized starting materials. Over the past two decades, the direct sulfuration of C-H bonds has evolved into a straightforward, atom- and step-economical method for the preparation of organosulfur compounds. This review aims to provide an up-to-date discussion on direct C-H disulfuration, dithiocarbamation, xanthylation, thiocarbamation and thiocarbonation, with a special focus on describing scopes and mechanistic aspects. Moreover, the synthetic limitations and applications of some of these methodologies, along with the key unsolved challenges to be addressed in the future are also discussed. The majority of examples covered in this review are accomplished via metal-free, photochemical or electrochemical approaches, which are in alignment with the overraching objectives of green and sustainable chemistry. This comprehensive review aims to consolidate recent advancements, providing valuable insights into the dynamic landscape of efficient and sustainable synthetic strategies for these crucial classes of organosulfur compounds.

Recent advances in selective mono-/dichalcogenation and exclusive dichalcogenation of C(sp2)-H and C(sp3)-H bonds

Organochalcogen compounds are prevalent in numerous natural products, pharmaceuticals, agrochemicals, polymers, biological molecules and synthetic intermediates. Direct chalcogenation of C-H bonds has evolved as a step- and atom-economical method for the synthesis of chalcogen-bearing compounds. Nevertheless, direct C-H chalcogenation severely lags behind C-C, C-N and C-O bond formations. Moreover, compared with the C-H monochalcogenation, reports of selective mono-/dichalcogenation and exclusive dichalcogenation of C-H bonds are relatively scarce. The past decade has witnessed significant advancements in selective mono-/dichalcogenation and exclusive dichalcogenation of various C(sp2)-H and C(sp3)-H bonds via transition-metal-catalyzed/mediated, photocatalytic, electrochemical or metal-free approaches. In light of the significance of both mono- and dichalcogen-containing compounds in various fields of chemical science and the critical issue of chemoselectivity in organic synthesis, the present review systematically summarizes the advances in these research fields, with a special focus on elucidating scopes and mechanistic aspects. Moreover, the synthetic limitations, applications of some of these processes, the current challenges and our own perspectives on these highly active research fields are also discussed. Based on the substrate types and C-H bonds being chalcogenated, the present review is organized into four sections: (1) transition-metal-catalyzed/mediated chelation-assisted selective C-H mono-/dichalcogenation or exclusive dichalcogenation of (hetero)arenes; (2) directing group-free selective C-H mono-/dichalcogenation or exclusive dichalcogenation of electron-rich (hetero)arenes; (3) C(sp3)-H dichalcogenation; (4) dichalcogenation of both C(sp2)-H and C(sp3)-H bonds. We believe the present review will serve as an invaluable resource for future innovations and drug discovery.

[Effects on extravascular lung water of lung protective ventilation strategy applied on piglets with acute respiratory distress syndrome induced by paraquat]

Objective: To study the effects on extravascular lung water of lung protective ventilation strategy applying on piglets with acute respiratory distress syndrome (ARDS) induced by paraquat (PQ) under pulse indicating continuous cardiac output (PiCCO) monitoring. Methods: The piglets models with ARDS induced by PQ were established in June 2020 and all of them were received mechanical ventilation and divided into three groups according to tidal volume (V(T)) : small V(T) group (6 ml/kg) , middle V(T) group (10 ml/kg) and large V(T) group (15 ml/kg) , there were 5 piglets in each group. The positive end expiratory pressure (PEEP) were all setup on 10 cmH(2)O. The indexes such as arterial blood gas analysis, oxygenation index (OI) , extravascular lung water index (ELWI) and pulmonary vascular permeability index (PVPI) were monitored at time of before the model was established (baseline) , time of the model was established (t(0)) and 2 h (t(2)) , 4 h (t(4)) , 6 h (t(6)) after mechanical ventilation. Lung tissue were punctured at time of baseline, t(0) and t(6) to be stained by Hematoxylin-eosin (HE) staining and pulmonary pathology were observed under light microscopy. Results: The heart rate (HR) , mean arterial pressure (MAP) and partial pressure of carbon dioxide (PaCO(2)) of all groups were higher than the base value while the pH values, partial pressure of oxygen (PaO(2)) and OI were lower than the base value when the models were established (P<0.05) . After mechanical ventilation, the HR and MAP values of all groups at t(2), t(4) and t(6) were lower than t(0) while the PaCO(2) of t(4) and t(6) were all higher than t(0), the differences were statistically significant (P<0.05) . The PaO(2) and OI of all groups showed a trend of rising at first and then decreasing after mechanical ventilation. The MAP, PaO(2), PaCO(2) and OI of the middle V(T) group and large V(T) group were apparently lower than that of the small V(T) group at t(2), t(4) and t(6) (P<0.05) . The ELWI and PVPI at t(0) of all groups were higher than that of baseline (P<0.05) . The ELWI of the small V(T) group at t(6) were lower than t(0) of the same group and t(6) of the middle V(T) group and large V(T) group (P<0.05) . HE staining showed congestion and edema of alveolar tissue, swelling of capillaries, exudation of red blood cells and widening of alveolar septum in piglets after successful modeling. And further widening of alveolar septum and rupture of alveolar septum could be seen in the lung tissues of each group at t(6), and the injury was the slightest in the small V(T) group. Conclusion: The lung protective ventilation strategy can alleviate the extravascular lung water and ARDS induced by PQ and improve oxygenation.

[To discuss the problems existing in the labor ability appraisal of an occupational chronic benzene poisoning incidence]

Three female workers in a golf club production company in Guangzhou were diagnosed with occupational chronic mild benzene poisoning. Two of the female workers were assessed as Grade 7 disabilities. One female worker showed the symptoms of the decline of whole blood cells for unknown reasons in the later stages of the medical period. The final assessment was a Class 5 disability. The problems in this work ability appraisal include: the injury condition of the patient who has not been stable during the work ability appraisal, and the contradiction between the disability grade and the occupational disease diagnosis conclusion. In order to avoid similar situations, the following recommendations are recommended: after the worker's injury situation is relatively stable, the assessment will be conducted, the employer will actively exercise the right to review and appraisal, and the diagnosis of occupational diseases will be included in the evaluation criteria for disability grade.

Effects of selection for ethanol preference on gene expression in the nucleus accumbens of HS-CC mice

Previous studies on changes in murine brain gene expression associated with the selection for ethanol preference have used F₂ intercross or heterogeneous stock (HS) founders, derived from standard laboratory strains. However, these populations represent only a small proportion of the genetic variance available in Mus musculus. To investigate a wider range of genetic diversity, we selected mice for ethanol preference using an HS derived from the eight strains of the collaborative cross. These HS mice were selectively bred (four generations) for high and low ethanol preference. The nucleus accumbens shell of naive S₄ mice was interrogated using RNA sequencing (RNA-Seq). Gene networks were constructed using the weighted gene coexpression network analysis assessing both coexpression and cosplicing. Selection targeted one of the network coexpression modules (greenyellow) that was significantly enriched in genes associated with receptor signaling activity including Chrna7, Grin2a, Htr2a and Oprd1. Connectivity in the module as measured by changes in the hub nodes was significantly reduced in the low preference line. Of particular interest was the observation that selection had marked effects on a large number of cell adhesion molecules, including cadherins and protocadherins. In addition, the coexpression data showed that selection had marked effects on long non-coding RNA hub nodes. Analysis of the cosplicing network data showed a significant effect of selection on a large cluster of Ras GTPase-binding genes including Cdkl5, Cyfip1, Ndrg1, Sod1 and Stxbp5. These data in part support the earlier observation that preference is linked to Ras/Mapk pathways.

Synthesis and application of waterborne polyurethane fluorescent composite

The waterborne polyurethane (WPU) was synthesized with isophorone diisocyanate (IPDI), polyethyleneglycol-400 (PEG-400), polyethyleneglycol-2000 (PEG-2000), dimethylolpropionic acid (DMPA) and trimethylolpropane (TMP) in this work. And the hydroxyethyl methacrylate (HEMA), butyl acrylate (BA) and methyl methacrylate (MMA) followed to modify the WPU by physical mixing and chemical integration to obtain the polyurethane/polyacrylate (PU/PA) and crosslinked polyurethane-acrylate (LPUA), respectively. Fourier transform infrared (FTIR) spectroscopy confirmed the presence of functional groups of LPUA. Thermogravimetric analysis (TGA) illustrated that the heat resistance of LPUA was better than that of PU/PA and WPU. And the effect of acrylate used to modify WPU on LPUA is also discussed. Lastly, LPUA was combined with Basic Red 1# to prepare fluorescent composite which could be used to dye cotton fabric. Such properties of fluorescent composite such as washing color fastness, heat-resistance were studied.

Molecular cloning and evolutionary analysis of captive forest musk deer bitter taste receptor gene T2R16

Sensing bitter tastes is crucial for most animals because it can prevent them from ingesting harmful food. This process is mainly mediated by the bitter taste receptors (T2R) that are largely expressed in the taste buds. Previous studies have identified some T2R gene repertoires. Marked variation in repertoire size has been noted among species. However, research on T2Rs is still limited and the mechanisms underlying the evolution of vertebrate T2Rs remain poorly understood. In the present study, we analyzed the structure and features of the protein encoded by the forest musk deer (Moschus berezovskii) T2R16 and submitted the gene sequence to NCBI GenBank. The results showed that the full coding DNA sequence (CDS) of musk deer T2R16 (GenBank accession No. KP677279) was 906 bp, encoding 301 amino acids, which contained ATG start codon and TGA stop codon, with a calculated molecular weight of 35.03 kDa and an isoelectric point of 9.56. The T2R16 protein receptor had seven conserved transmembrane regions. Hydrophobicity analysis showed that most amino acid residues in T2R16 protein were hydrophobic, and the grand average of hydrophobicity (GRAVY) was 0.657. Phylogenetic analysis based on this gene revealed that forest musk deer had the closest association with sheep (Ovis aries), as compared to cow (Bos taurus), Tursiops truncatus, and other species, whereas it was genetically farthest from humans (Homo sapiens). We hope these results would complement the existing data on T2R16 and encourage further research in this respect.

Enhanced minority carrier lifetimes in GaAs/AlGaAs core-shell nanowires through shell growth optimization

The effects of AlGaAs shell thickness and growth time on the minority carrier lifetime in the GaAs core of GaAs/AlGaAs core-shell nanowires grown by metal-organic chemical vapor deposition are investigated. The carrier lifetime increases with increasing AlGaAs shell thickness up to a certain value as a result of reducing tunneling probability of carriers through the AlGaAs shell, beyond which the carrier lifetime reduces due to the diffusion of Ga-Al and/or impurities across the GaAs/AlGaAs heterointerface. Interdiffusion at the heterointerface is observed directly using high-angle annular dark field scanning transmission electron microscopy. We achieve room temperature minority carrier lifetimes of 1.9 ns by optimizing the shell growth with the intention of reducing the effect of interdiffusion.

Clostridium difficile infection in hospitalized cancer patients in Beijing, China is facilitated by receipt of cancer chemotherapy

The purpose of this study was to determine the presence of Clostridium difficile infection (CDI) and risk factors for infection in hospitalized patients with diarrhea in a cancer hospital in Beijing, China. A total of 277 patients with hospital-associated diarrhea (HAD) were studied of which 41 (15%) were positive for fecal C. difficile toxin A/B. For each CDI case identified, a control with HAD but negative C. difficile specimen was enrolled to look for CDI risk factors. Receipt of cancer chemotherapy occurred in 20 (49%) patients with CDI and 9 (22.0%) patients with non-CDI HAD (OR3.39, 95%CI 1.78-10.05). Median length of chemotherapy before HAD developed was 39 days for those with CDI and 22 days for patients with CDI-negative HAD (P = 0.0391). The study found that CDI is commonly seen in cancer patients in China with increasing risk for patients who receive chemotherapy.

Ethyl 2-[1,3-dioxo-6-(piperidin-1-yl)-2,3-dihydro-1H-benz[de]isoquinolin-2-yl]acetate

In the title compound, C₂₁H₂₂N₂O₄, the naphthalimide unit is almost planar (r.m.s. deviation = 0.081Å). The carboximide N atom and the five C atoms of the eth­oxy­carbonyl­methyl substituent also lie close to a common plane (r.m.s. deviation = 0.119Å), which subtends an angle of 71.06 (8)° to the naphthalamide plane. The piperidine ring adopts a chair conformation. In the crystal, inter­molecular C—H⋯O hydrogen bonds link the mol­ecules into zigzag chains along the a axis.

Decolorization of cotton pulp black liquor by pleurotus ostreatus in a bubble-column reactor

Decolorization of cotton pulp black liquor by Pleurotus ostreatus B1 in a bubble-column reactor (BCR) was studied. The optimal conditions for the running of BCR are 30 degrees C, pH 6.0, aeration rate 1.2 L min(-1), and mycelial age 7 days. Under the optimal conditions, the BCR was run for four cycles (each cycle, 12 days) and the same mycelial pellets were reused. The ultimate decolorization and COD removal rates are 76% and 80%, respectively.

A database designed to computationally aid an experimental approach to alternative splicing

A unique microarray approach has been developed to profile alternative splicing in the cell. To support the development of this approach, we have developed the Manually Annotated Alternatively Spliced Events (MAASE) database system, which is a unique alternative splicing information resource designed specifically with experimentalists in mind. MAASE is an online resource for the convenient access, identification, and annotation of alternative splicing events (ASEs). MAASE consists of two components: an annotation system and a curated database. The annotation system is a web-based workspace that combines manual and computational approaches to identifying and annotating ASEs, a combination that is vital if a comprehensive collection is to be obtained. The annotation system is publicly available and provides a scalable solution to acquiring as well as contributing to annotated ASEs. MAASE annotated ASEs are deposited into the database component, which can either be queried one entry at a time or multiple entries at a time with convenient access to alternatively spliced junctional and surrounding sequences to facilitate the design of microarray experiments.

Balance of Th1/Th2 cytokines associated with the preventive effect of incomplete Freund's adjuvant on the development of adjuvant arthritis in LEW rats

Complete Freund's adjuvant (CFA) could induce adjuvant arthritis (AA) in LEW rats and incomplete Freund's adjuvant (IFA) could induce oil induced arthritis (OIA) in DA but not in LEW rats. Lymph node cells (LNCs) from these AA and OIA rats showed increased mRNA expression of IFN-gamma, IL-2 and TNF-alpha but not IL-4. LNCs from IFA immunized LEW rats showed increased expression of IL-4, reduced expression of IFN-gamma and TNF-alpha and no IL-2, in contrast to IFA immunized DA rats. The pretreatment of IFA before CFA challenge could completely prevent AA in LEW rats and their LNCs showed increased expression of IL-4 and IFN-gamma but not IL-2 and TNF-alpha. In F1 (LEW x DA) rats, IFA could not induce OIA but the pretreatment of IFA before CFA challenge could induce very mild AA with 80% incidence, LNCs showing an elevated expression of all the above cytokines. These findings suggest that increased Th1 cytokine expression is associated with disease development and that increased IL-4 expression or the balance of Th2 over Th1 cytokine expression plays an important regulatory role in disease development.

Dimethyl dioctadecyl ammonium bromide (DDA)-induced arthritis in rats: a model of experimental arthritis

A single intradermal injection of 2 mg of dimethyl dioctadecyl ammonium bromide (DDA) in phosphate buffered saline (PBS) could induce polyarthritis in both LEW and DA rats with low incidence and severity whereas 2 mg of DDA in incomplete Freund's adjuvant (IFA) could induce very severe polyarthritis with 100% incidence in LEW rats. Histology of DDA-induced arthritis (DIA) revealed cellular infiltration, synovial hypertrophy, development of granulation tissue, destruction of cartilage and bone deformation in the articular joints. Lymph node cells (LNCs) but not immunoglobulin fractions from the DIA rats successfully transferred the severe disease into the naive recipients. A challenge injection of DDA in IFA in the rats, which had recovered from the DIA, could reactivate the disease. It is thus concluded that DDA has arthritis-inducing ability in the rats which is potentiated by IFA and the DIA is a cell-mediated immune disease which might be a model of experimental arthritis.

The preventive effects of incomplete Freund's adjuvant and other vehicles on the development of adjuvant-induced arthritis in Lewis rats

The present study showed a novel finding that the development of adjuvant-induced arthritis (AA) in Lewis rats was completely prevented by incomplete Freund's adjuvant (IFA) injected 21 or 28 days before complete Freund's adjuvant (CFA) challenge. Hexadecane also completely prevented AA and squalane, methyl oleate and pristane moderately prevented AA, though pristane by itself induced mild arthritis in two out of five rats. Concanavalin A-stimulated lymph node cells (LNCs) isolated from AA rats were able to adoptively transfer the severe polyarthritis to all the naive recipients or even to the IFA pretreated recipients with earlier onset and more rapid progression than those of AA. The LNCs from the donors who had been pretreated with IFA and subsequently challenged with CFA could induce mild arthritis in only two out of eight naive recipients, whereas all the recipients who were challenged with CFA immediately after intravenous injection of these LNCs developed significantly less severe arthritis. However, the LNCs from IFA-pretreated donors failed to prevent AA. According to the T helper type 1 (Th1)/Th2 paradigm, it was suggested that the adjuvant-active vehicles such as IFA, hexadecane, squalane, methyl oleate and pristane, can affect and deviate the Th1/Th2 balance of immune responses in host. CFA could promote the propagation of Th2 cells rather than Th1 cells in these vehicle-pretreated rats through as yet undetermined mechanisms, eventually resulting in the prevention of AA. Finally, we discussed a regulatory role of adjuvant vehicles for induction and suppression of AA.