Surface coordination layer passivates oxidation of copper.

Owing to its high thermal and electrical conductivities, its ductility and its overall non-toxicity1-3, copper is widely used in daily applications and in industry, particularly in anti-oxidation technologies. However, many widespread anti-oxidation techniques, such as alloying and electroplating1,2, often degrade some physical properties (for example, thermal and electrical conductivities and colour) and introduce harmful elements such as chromium and nickel. Although efforts have been made to develop surface passivation technologies using organic molecules, inorganic materials or carbon-based materials as oxidation inhibitors4-12, their large-scale application has had limited success. We have previously reported the solvothermal synthesis of highly air-stable copper nanosheets using formate as a reducing agent13. Here we report that a solvothermal treatment of copper in the presence of sodium formate leads to crystallographic reconstruction of the copper surface and formation of an ultrathin surface coordination layer. We reveal that the surface modification does not affect the electrical or thermal conductivities of the bulk copper, but introduces high oxidation resistance in air, salt spray and alkaline conditions. We also develop a rapid room-temperature electrochemical synthesis protocol, with the resulting materials demonstrating similarly strong passivation performance. We further improve the oxidation resistance of the copper surfaces by introducing alkanethiol ligands to coordinate with steps or defect sites that are not protected by the passivation layer. We demonstrate that the mild treatment conditions make this technology applicable to the preparation of air-stable copper materials in different forms, including foils, nanowires, nanoparticles and bulk pastes. We expect that the technology developed in this work will help to expand the industrial applications of copper.

An operator-based expression toolkit for Bacillus subtilis enables fine-tuning of gene expression and biosynthetic pathway regulation.

SignificanceA gene regulatory system is an important tool for the engineering of biosynthetic pathways of organisms. Here, we report the development of an inducible-ON/OFF regulatory system using a malO operator as a key element. We identified and modulated sequence, position, numbers, and spacing distance of malO operators, generating a series of activating or repressive promoters with tunable strength. The stringency and robustness are both guaranteed in this system, a maximal induction factor of 790-fold was achieved, and nine proteins from different organisms were expressed with high yields. This system can be utilized as a gene switch, promoter enhancer, or metabolic valve in synthetic biology applications. This operator-based engineering strategy can be employed for developing similar regulatory systems in different microorganisms.

Highly flexible cell membranes are the key to efficient production of lipophilic compounds.

Lipophilic compounds have a variety of positive effects on human physiological functions and exhibit good effects in the prevention and treatment of clinical diseases. This has led to significant interest in the technical applications of synthetic biology for the production of lipophilic compounds. However, the strict selective permeability of the cell membrane and the hydrophobic nature of lipophilic compounds pose significant challenges to their production. During fermentation, lipophilic compounds tend to accumulate within cell membrane compartments rather than being secreted extracellularly. The toxic effects of excessive lipophilic compound accumulation can threaten cell viability, while the limited space within the cell membrane restricts further increases in production yield. Consequently, to achieve efficient production of lipophilic compounds, research is increasingly focused on constructing robust and multifunctional microbial cell factories. Utilizing membrane engineering techniques to construct highly flexible cell membranes is considered an effective strategy to break through the upper limit of lipophilic compound production. Currently, there are two main approaches to cell membrane modification: constructing artificial storage compartments for lipophilic compounds and engineering the cell membrane structure to facilitate product outflow. This review summarizes recent cell membrane engineering strategies applied in microbial cell factories for the production of liposoluble compounds, discussing the challenges and future prospects. These strategies enhance membrane flexibility and effectively promote the production of liposoluble compounds.

Spinel Nanostructures for the Hydrogenation of CO2 to Methanol and Hydrocarbon Chemicals.

Composite oxides have been widely applied in the hydrogenation of CO/CO2 to methanol or as the component of bifunctional oxide-zeolite for the synthesis of hydrocarbon chemicals. However, it is still challenging to disentangle the stepwise formation mechanism of CH3OH at working conditions and selectively convert CO2 to hydrocarbon chemicals with narrow distribution. Here, we investigate the reaction network of the hydrogenation of CO2 to methanol over a series of spinel oxides (AB2O4), among which the Zn-based nanostructures offer superior performance in methanol synthesis. Through a series of (quasi) in situ spectroscopic characterizations, we evidence that the dissociation of H2 tends to follow a heterolytic pathway and that hydrogenation ability can be regulated by the combination of Zn with Ga or Al. The coordinatively unsaturated metal sites over ZnAl2Ox and ZnGa2Ox originating from oxygen vacancies (OVs) are evidenced to be responsible for the dissociative adsorption and activation of CO2. The evolution of the reaction intermediates, including both carbonaceous and hydrogen species at high temperatures and pressures over the spinel oxides, has been experimentally elaborated at the atomic level. With the integration of a series of zeolites or zeotypes, high selectivities of hydrocarbon chemicals with narrow distributions can be directly produced from CO2 and H2, offering a promising route for CO2 utilization.

Dual Modification Strategy for Enhanced Cycling and Rate Performance of Ni-Rich Cathode Materials in Lithium-Ion Batteries.

A great challenge in the commercialization process of layered Ni-rich cathode material LiNixCoyMn1-x-yO2 (NCM, x ≥ 80%) for lithium-ion batteries is the surface instability, which is exacerbated by the increase in nickel content. The high surface alkalinity and unavoidable cathode/electrolyte interface side reactions result in significant decrease for the capacity of NCM material. Surface coating and doping are common and effective ways to improve the electrochemical performance of Ni-rich cathode material. In this study, an in situ reaction is induced on the surface of secondary particles of NCM material to construct a stable lithium sulfate coating, while achieving sulfur doping in the near surface region. The synergistic modification of lithium sulfate coating and lattice sulfur doping significantly reduced the content of harmful residual lithium compounds (RLCs) on the surface of NCM material, suppressed the side reactions between the cathode material surface and electrolyte and the degradation of surface structure of the NCM material, effectively improved the rate capability and cycling stability of the NCM material.

Cut-off values of haemoglobin and clinical outcomes in incident peritoneal dialysis: the PDTAP study.

BACKGROUND: To explore the cut-off values of haemoglobin (Hb) on adverse clinical outcomes in incident peritoneal dialysis (PD) patients based on a national-level database. METHODS: The observational cohort study was from the Peritoneal Dialysis Telemedicine-assisted Platform (PDTAP) dataset. The primary outcomes were all-cause mortality, major adverse cardiovascular events (MACE) and modified MACE (MACE+). The secondary outcomes were the occurrences of hospitalization, first-episode peritonitis and permanent transfer to haemodialysis (HD). RESULTS: A total of 2591 PD patients were enrolled between June 2016 and April 2019 and followed up until December 2020. Baseline and time-averaged Hb <100 g/l were associated with all-cause mortality, MACE, MACE+ and hospitalizations. After multivariable adjustments, only time-averaged Hb <100 g/l significantly predicted a higher risk for all-cause mortality {hazard ratio [HR] 1.83 [95% confidence interval (CI) 1.19-281], P = .006}, MACE [HR 1.99 (95% CI 1.16-3.40), P = .012] and MACE+ [HR 1.77 (95% CI 1.15-2.73), P = .010] in the total cohort. No associations between Hb and hospitalizations, transfer to HD and first-episode peritonitis were observed. Among patients with Hb ≥100 g/l at baseline, younger age, female, use of iron supplementation, lower values of serum albumin and renal Kt/V independently predicted the incidence of Hb <100 g/l during the follow-up. CONCLUSION: This study provided real-world evidence on the cut-off value of Hb for predicting poorer outcomes through a nation-level prospective PD cohort.

Up-regulation of miR-126 via DNA methylation in hypoxia-preconditioned endothelial cells may contribute to hypoxic tolerance of neuronal cells.

BACKGROUND: Endothelial cells (ECs) can confer neuroprotection by secreting molecules. This study aimed to investigate whether DNA methylation contributes to the neuroprotective gene expression induced by hypoxia preconditioning (HPC) in ECs and to clarify that the secretion of molecules from HPC ECs may be one of the molecular mechanisms of neuroprotection. METHODS: Human microvascular endothelial cell-1 (HMEC-1) was cultured under normal conditions (C), hypoxia(H), and hypoxia preconditioning (HPC), followed by the isolation of culture medium (CM). SY5Y cell incubated with the isolated CM from HMEC-1 was exposed to oxygen-glucose deprivation (OGD). The DNA methyltransferases (DNMTs), global methylation level, miR-126 and its promotor DNA methylation level in HMEC-1 were measured. The cell viability and cell injury in SY5Y were detected. RESULTS: HPC decreased DNMTs level and global methylation level as well as increased miR-126 expression in HMEC-1. CM from HPC treated HMEC-1 also relieved SY5Y cell damage, while CM from HMEC-1 which over-expression of miR-126 can reduce injury in SY5Y under OGD condition. CONCLUSIONS: These findings indicate EC may secrete molecules, such as miR-126, to execute neuroprotection induced by HPC through regulating the expression of DNMTs.

ATF3/EGR1 regulates myocardial ischemia/reperfusion injury induced autophagy and inflammation in cardiomyocytes.

Myocardial ischemia/reperfusion injury (MIRI) is an irreversible adverse event during the management of coronary heart disease that lacks effective controls. The underlying mechanism of MIRI still requires further investigation. Recent studies have suggested that overexpression of ATF3 protects against MIRI by regulating inflammatory responses, ferroptosis, and autophagy. The downstream target of ATF3, EGR1, also showed cardioprotective properties against MIRI by promoting autophagy. Therefore, further investigating the effect of ATF3/EGR1 pathway on MIRI-induced inflammation and autophagy is needed. Cardiomyocyte MIRI model was established by challenging H9C2 cells with hypoxia/reoxygenation (H/R). The ATF3 overexpression-H/R cell model by transfecting ATF3 plasmid into the H9C2 cell line. The transcription levels of ATF3 and EGR1 were determined using RT-qPCR, the levels of TNF-α and IL-6 were determined using ELISA kits, the protein expression of LC3 I, LC3 II, and P62 was determined via WB, and microstructure of H9C2 cell was observed by transmission electron microscopy (TEM). Overexpression of ATF3 significantly downregulated Egr1 levels, indicating that EGR1 might be the target of ATF3. By upregulating ATF3 levels, the extracellular levels of the inflammatory cytokines TNF-α and IL-6 significantly decreased, and the protein expression of the autophagy markers LC3 I, LC3 II, and P62 significantly increased. TEM results revealed that the cell line in the H/R-ATF3 group exhibited a higher abundance of autophagosome enclosures of mitochondria. The results indicated that ATF3/EGR1 may alleviate inflammation and improve autophagy in an H/R-induced MIRI model of cardiomyocytes.

Comparing the modified socket-shield technique with the conventional immediate implantation technique in the anterior dentition: A 5-year retrospective clinical study.

AIMS: The aim of this retrospective clinical study was to compare the 5-year radiological and clinical outcomes of patients undergoing immediate implantation with or without the modified socket-shield technique. MATERIALS AND METHODS: Patients who underwent anterior tooth replacement via the modified socket-shield technique (MSST) or the conventional immediate implantation technique (CIIT) between 2016 and 2017 were included. The labial bone thickness was assessed at different measurement levels (0, 2, 4 and 6 mm apical to the implant shoulder (IS)) postoperatively (T1), 6 months postoperatively (T2) and 5 years postoperatively (T3). The pink aesthetic score (PES) was evaluated before surgery (T0) and at T2 and T3. Implant success, complications and patient satisfaction were evaluated at every visit. RESULTS: Thirty-six patients (18 in the MSST group) underwent follow-up for 5 years, with no cases of implant failure. Two cases of exposure were detected in the MSST group, but there were no significant effects on hard or soft tissue. Patients in the MSST group showed less and more stable bone resorption than did those in the CIIT group at any measurement level and any time. A higher PES was achieved in the MSST group. Patient satisfaction was similar in both groups. CONCLUSIONS: The MSST is a reliable immediate implantation method because of its ability to preserve the alveolar bone and provide superior recovery of aesthetics.

First Report of Bulb Rot Disease of Banana Caused by Klebsiella variicola in China.

Banana (Musa spp.) is an economically important fruit and food crop globally as well as in China. In March 2023, a bulb rot disease was observed on more than 20% of cultivated dwarf bananas in a plantation in Wuming County of Guangxi Province, a major hub of banana production in China. Infected plants showed crackles at the basal part of stem and were relatively dwarf, while yellowing of the leaves was not observed. When the rhizomes were cut open, water-soaked lesions with a yellow or black margin can be seen in the bulb. In severe infections, the internal tissue became dry or wet rot, and there was typical dark-brown cavity formation in the bulb. The rot was limited to the bulb. To isolate the causal agent, dissected diseased tissues (5×5 mm) were surface sterilized with 75% ethanol (30 s) and 2% NaClO (3 min), followed by three rinses with sterile water. The sterilized sections were soaked in 2 mL of sterile water and shaken for 5 min in a vortex oscillator. The suspension was streaked on Luria-Bertani (LB) agar medium, and incubated at 28℃ for 24 h. Single colonies were re-streaked three times to obtain purified isolation. Twelve pure bacterial cultures with similar morphology were isolated from three plants taken from the field. The bacterial colonies were yellowish white, mucoid, round, and raised with translucent surfaces on the LB agar plate. Three strains Gxkv1, Gxkv2 and Gxkv3 were selected for further analyses. The 16S rDNA gene (GenBank Accession OR461756, PP094726 and PP109349) were amplified using primer pair 27F/1492R (Frank et al. 2008). Comparing 16S sequences against GenBank showed 99.86%-100% sequence identity to Klebsiella variicola strain (MZ475068) for the three isolates Gxkv1 (1,398/1,398 bp), Gxkv2 (1,398/1,396 bp) and Gxkv3 (1,398/1,398 bp). A multilocus phylogenetic analysis was conducted by neighbor-joining method (1,000 bootstrap values) based on three housekeeping gene sequences of gyrA (GenBank Accession No. OR515493, PP105747, PP105748), rpoB (OR515494, PP105751, PP105752 ) and infB (OR515495, PP105749, PP105750) genes which were amplified by gyrA-A/gyrA-C, CM31b/CM7 and infB867F/infB1819R primer sets, respectively (Rosenblueth et al. 2004). The results of phylogenetic analysis showed the three strains belong to the K. variicola clade. A pathogenicity test was conducted on six healthy 3-month-old dwarf banana plants by spraying 10 mL of bacterial suspensions of Gxkv1 (108 CFU/mL) into the rhizome which wounded with a sterilized needle; another six healthy control plants were sprayed with 10 mL of sterile water. Following inoculation, the plants were placed in a greenhouse at 28-32°C. After 30 days, all inoculated plants showed symptoms similar to those observed in the field, while the control plants remained healthy. Bacteria were successfully reisolated from the symptomatic tissues and identified to be K. variicola by PCR mentioned above. K. variicola has been reported to cause rhizome rot of banana in India (Loganathan et al. 2021), and to cause plantain soft rot in Haiti (Fulton et al. 2021). Besides, previous reports from China only showed K. variicola causing banana sheath rot (Fan et al. 2015, Sun et al. 2023). To our knowledge, this is the first report of bulb rot disease of banana caused by K. variicola in Guangxi Province, China. This finding will provide important information for studying the epidemiology and management of this pathogen.

First Report of Fusarium kyushuense Causing Leaf Spot on Sweet Persimmon in China.

Sweet persimmon (Diospyros kaki L.) is a fruit of significant nutritional and commercial value in Asia. In summer 2023, leaf spots were observed affecting 20 to 30% of sweet persimmon trees in a commercial orchard located in Gongcheng City, Guangxi, China. Initially, the infected leaves exhibited sparse light brown spots on their upper surface, which subsequently evolved into brown circular to irregular lesions encircled by a yellow halo. Eventually, these lesions became densely distributed across the leaves leading to insufficient nutrient accumulation in the fruit. To isolate the pathogen, diseased leaves were cut into small pieces (5×5 mm), disinfected with 75% ethanol for 15 seconds, followed by 1% NaClO for 1minute, rinsed three times with sterile water, and then transferred onto potato dextrose agar (PDA) plates. The plates were then incubated in darkness for 3 days at 25°C. Pure cultures were obtained using the hyphal-tip method and single-spore isolation. On PDA, the colonies initially appeared fluffy and white after 24 hours, turning yellowish or red after 3 days. Macroconidia (average length of 26.1 µm in length × 4.3 µm in width, n = 50) exhibited dorsiventral curvature and were hyaline, with 3 to 5 septa. Microconidia (average length of 9.45 µm in length × 3.4 µm in width, n = 50) were hyaline, aseptate, and oval. Two representative isolates, Gxfky1 and Gxfky2, were selected for further molecular analyses. Their internal transcribed spacer (ITS) region rDNA gene were amplified via PCR and sanger sequenced (GenBank Accession Nos. PP506475, PP506593) using the primer pair ITS1/ITS4 (White et al. 1990), showing more than 99% sequence identity with Fusarium kyushuense type-material strain NRRL3509 (NR_152943) according to BLASTn analysis in NCBI. To further confirm the identity of the isolates, four gene sequences were amplified: RPB1 (PP532864, PP532865), RPB2 (PP532866, PP532867), TEF1 (PP580505, PP580506), and TUB2 (PP532862, PP532863), using the F5/G2R, 5f2/11ar, EF1/EF2, and T1/T2 primer sets, respectively (O'Donnell et al., 1997; O'Donnell et al., 2010). A multi-locus maximum likelihood phylogenetic analysis revealed that Gxfky1 and Gxfky2 clustered with strains F. kyushuense with 100% bootstrap support. Pathogenicity tests using Gxfky1 and Gxfky2 were conducted on leaves of two-year-old sweet persimmon plants using non-wound inoculation. Specifically, 5-mm mycelial plugs and sterile agar plugs were placed on six leaves and secured with cling film, with six plugs each for the inoculation treatment and negative control, respectively. They were then incubated in a greenhouse at room temperature (25 ± 2°C) with a relative humidity of 70 to 80%. After 5 days, the same symptoms on naturally infected plants were observed on leaves inoculated with mycelium, while no symptoms were observed on the controls. The same fungus were reisolated from the inoculated leaves and identified based on morphology and the TEF1 gene sequence, thus fulfilling Koch's postulates. Fusarium kyushuense has previously been reported to cause diseases in various plant species, including maize (Cao et al., 2021), rice (Wang et al., 2024), and tobacco (Wang et al., 2013). To our knowledge, this is the first report of F. kyushuense causing leaf spot on sweet persimmon in China, which expands the known host range of this pathogen.

First Report of Colletotrichum cordylinicola Causing Anthracnose on Cordyline fruticosa in China.

Cordyline fruticosa is a shrub plant, commonly used in landscape, and distributed in the tropical regions of southern China. In September 2022, anthracnose symptoms were found on this species in Nanning, Guangxi, China. The disease incidence was between 30% to 80% and disease severity was 10% to 30% in five surveyed planting areas. The symptoms initially appeared as small, round, brown spots on leaves. As the disease developed, the lesions turned gray-white with brown borders and yellow halos. Some spots coalesced into larger irregular shapes and even leading to leaf blight. Small segments of the diseased tissues (3×3 mm) were cut from the leaves, surface-sterilized by dipping in a 1% sodium hypochlorite solution for 1 min, rinsed three times with sterile distilled water, and plated on potato dextrose agar (PDA). These plates were incubated at 28°C in the dark for 5 days. Ten fungal isolates with similar morphology were consistently isolated from these diseased tissues. The colonies on PDA were initially white with sparse aerial mycelia and turned pale orange with abundant orange conidial masses on the center after 8 days of culture. The reverse color was pale orange. No sclerotia or setae were found in culture. Conidia were single-celled, hyaline, straight, cylindrical with round ends, and 12.2 to 17.8 µm long (mean 14.9 µm) and 3.9 to 7.3 µm wide (mean 4.8 µm, n=50). The morphological characteristics of these isolates were similar to the Colletotrichum cordylinicola (Sharma et al., 2014). Genomic DNA of two isolates Z3 and Z4 generated from monospore culture was extracted using a fungal DNA extraction kit (Solarbio, Beijing, China). Partial sequences of internal transcribed spacer (ITS), partial actin (ACT), chitin synthase (CHS-1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and beta-tubulin (TUB2) were amplified using the primer pairs ITS1/ITS4, ACT-512F/ACT-783R, CHS-79F/CHS-345R, GDF1/GDR1, and BT2A/BT2B (Lin et al., 2022), respectively. All the sequences (GenBank accession nos. OQ509909, OQ509910, OQ658690, OQ658691, and OK649310 to OK649314) showed 99% to 100% identity with those of C. cordylinicola in GenBank database. A phylogenetic tree based on concatenated sequences of ITS, ACT, CHS-1, TUB, and GAPDH using maximum likelihood analysis by MEGA X software revealed that Z3 and Z4 clade with reference strains of C. cordylinicola (OJX010226 and MK935473). Based on morphological observation and multi-gene sequence analysis, the isolates were identified as C. cordylinicola (Phoulivong et al., 2010). To assess their pathogenicity, conidial suspensions (106 conidia/ml) of C. cordylinicola were inoculated onto 10 healthy living leaves wounded by slight puncturing (10 µl/wounded spot). Control leaves were treated with sterile water. All inoculated and control plants were maintained under high relative humidity (~90%) and 28℃ in a climate chamber. After 8 days, all the inoculated leaves showed brown lesions resembling natural symptoms, whereas the control group remained symptom-free. The same fungus was re-isolated from the symptomatic leaves, thus completing Koch's postulates. C. cordylinicola is a species of the C. gloeosporioides complex (Weir et al., 2012). It has been reported to cause anthracnose on C. fruticosa in USA and Thailand (Phoulivong et al., 2010; Sharma et al., 2014). To our knowledge, this is the first report of C. cordylinicola causing anthracnose on C. fruticosa in China. Knowing the causal agent is essential to control the serious disease effectively.

Follow-up Value of Hip Medial Ultrasound in Infants and Children With Developmental Dysplasia of the Hip Treated With Reduction and Spica Casting.

OBJECTIVE: Closed or open reduction and spica casting are common treatments for children aged 6 to 18 months, as well as infants aged 0 to 6 months whose harness treatment for developmental dysplasia of the hip (DDH) was unsuccessful. The study aimed to quantify the distance between the femoral head and the acetabulum after closed or open reduction and evaluate the dynamic docking progression of the femoral head using serial hip medical ultrasound. METHODS: We retrospectively reviewed the medical records and hip medial ultrasound images of a consecutive series of patients with DDH who underwent spica casting after reduction and compared images obtained immediately after reduction and at follow-up. The first cast (stage I) was maintained for 2 to 3 months and scheduled for outpatient repeat ultrasound in 4 to 8 weeks. Then the second cast was placed (stage II), lasting for another 2 to 3 months. The triradiate cartilage-femoral head distance (TFD) was measured in the acetabulum coronal mid-sectional plane. The Wilcoxon signed-rank test was used to compare the TFD values. RESULTS: This study included 49 patients. All patients underwent hip medial ultrasound 0 to 3 days after stage I (time 1) and 4 to 8 weeks (time 2) postoperatively, with 24 patients reviewed again 0 to 7 days after stage II. The TFD values in time 1 and time 2 were 6.0 (5.0, 9.0) mm and 5.0 (3.6, 7.0) mm, respectively. There was a statistically significant difference between times 1 and 2 regarding TFD values in 49 close-reduction hips (6.0 vs 5.0 mm, P < 0.001). Similar findings were also observed in 13 open-reduction hips (6.0 vs 5.0 mm, P = 0.023). CONCLUSIONS: Hip medial ultrasonography during the period of cast immobilization after reduction in children with DDH can objectively and quantitatively show the dynamic change of the distance between the femoral head and the acetabulum, and can be used to assess reduction of the hip and progression of femoral head docking. LEVEL OF EVIDENCE: Level II-prognostic study.

[Research progress on chemical constituents from Kadsura genus and its pharmacological activities and clinical application].

The 29 plant species in the Kadsura genus of the Schisandraceae family are mainly distributed in eastern and southeas-tern Asia. Ten species of plants in this genus are distributed in China, some of which are folk medicinal plants with activating blood circulation, relieving pain, dispelling wind, and dehumidifying effects. Their main constituents are lignans and triterpenes. The current pharmacology and clinical studies have shown that their extracts and constituents have anti-rheumatoid arthritis, liver protection, antioxidation, anti-inflammatory, and other biological activities. The rheumatologic and liver diseases can also be treated with the plants in the clinic. The new chemical constituents reported in the last decade(2012 to date) from the plants of Kadsura genus in China, as well as their pharmacological effects and clinical applications in recent years were reviewed, so as to provide a theoretical basis for further research on the genus.

[Chemical constituents from roots of Kadsura heteroclita].

The dichloromethane fraction of Kadsura heteroclita roots was separated and purified by chromatographic techniques(e.g., silica gel, Sephadex LH-20, ODS, MCI column chromatography) and semi-preparative HPLC. Twenty compounds were isolated from K. heteroclita, and their structures were identified by NMR, MS, UV, and X-ray single crystal diffraction techniques. Twenty compounds were isolated from K. heteroclita, which were identified as xuetongdilactone G(1), mallomacrostin C(2), 3,4-seco(24Z)-cychmrt-4(28),24-diene-3,26-dioic acid 3-methyl ester(3), nigranoic acid(4), methyl ester schizanlactone E(5), schisandronic acid(6), heteroclic acid(7), wogonin(8),(2R,3R)-4'-O-methyldihydroquercetin(9), 15,16-bisnor-13-oxo-8(17),11E-labdadien-19-oic acid(10), stigmast-4-ene-6ß-ol-3-one(11), psoralen(12),(1R,2R,4R)-trihydroxy-p-menthane(13), homovanillyl alcohol(14), 2-(4-hydroxyphenyl)-ethanol(15), coniferaldehyde(16),(E)-7-(4-hydroxy-3-methoxyphenyl)-7-methylbut-8-en-9-one(17), acetovanillone(18), vanillic acid(19) and vanillin(20). Compound 1 is a new compound named xuetongdilactone G. Compounds 2-3 and 8-20 are isolated from K. heteroclita for the first time.

Hydrogen Bond Network Induced by Surface Ligands Shifts the Semi-hydrogenation Selectivity over Palladium Catalysts.

Tuning the metal-ligand interfaces of heterogeneous catalysts has emerged as an effective strategy to optimize their catalytic performance. However, improving the selectivity via organic modification remains a challenge so far. In this work, we demonstrate a simple ligand modification by preparing cysteamine-coated ultrathin palladium nanosheets. The as-prepared catalyst exhibits excellent selectivity with durability during catalytic hydrogenation of terminal alkynes, superior to most previously reported ligand-protected palladium catalysts. Further study reveals that a zwitterionic transformation occurs on the palladium interface under the H2 conditions, generating a rigid hydrogen bond network. Such an unexpected effect beyond the traditional steric effect derived from van der Waals interactions makes the catalytic surface favor the hydrogenation of alkynes over alkenes without significantly sacrificing the catalytic activity. These results not only provide a unique steric effect concept for surface coordination chemistry but also provide a practical application to improve the selectivity and activity comprehensively.

Lewis Acid-Induced Reversible Disproportionation of TEMPO Enables Aqueous Aluminum Radical Batteries.

Nitroxide radicals, such as 2,2,6,6-tetramethylpiperidyl-1-oxy (TEMPO), are typical organic electrode materials featuring high redox potentials and fast electrochemical kinetics and have been widely used as cathode materials in multivalent metal-ion batteries. However, TEMPO and its derivatives have not been used in emerging rechargeable aluminum-ion batteries (AIBs) due to the known disproportionation and possible degradation of nitroxide radicals in acidic conditions. In this study, the (electro)chemical behavior of TEMPO is examined in organic and aqueous Lewis acid electrolytes. Through in situ (electro)chemical characterizations and theoretical computation, we reveal for the first time an irreversible disproportionation of TEMPO in organic Al(OTf)3 electrolytes that can be steered to a reversible process when switching to an aqueous media. In the latter case, a fast hydrolysis and ligand exchange between [Al(OTf)3TEMPO]- anion and water enable the overall reversible electrochemical redox reaction of TEMPO. These findings lead to the first design of radical polymer aqueous AIBs that are fire-retardant and air-stable, delivering a stable voltage output of 1.25 V and a capacity of 110 mAh g-1 over 800 cycles with 0.028% loss per cycle. This work demonstrates the promise of using nonconjugated organic electroactive materials for cost-effective and safe AIBs that currently rely on conjugated organic molecules.

Generating a hollow twisted correlated beam using correlated perturbations.

In this study, a twisted correlated optical beam with a dark hollow center in its average intensity is synthesized by correlated correlation perturbation and incoherent mode superposition. This new hollow beam has a topological charge (TC) mode with a zero value compared with a coherence vortex that has a TC mode with a nonzero value. We transform the twisted correlated beam from solid centered to dark hollow centered by constructing a correlation between the twist factor and the spot structure parameter. Theoretical and experimental results show that twist correlation makes the random optical beam an asymmetric orbital angular momentum spectral distribution and a tunable intensity center. Controlling the correlation parameters can make the focal spot of the twisted beam a dark core when the dominant mode of the TC is still zero. The new nontrivial beams and their proposed generation method provide important technical preparations for the optical particle manipulation with low coherence environment.

Photocatalytic Three-Component Reaction for the Synthesis of Multifunctional Diaryl Sulfides.

A photocatalytic three-component reaction of a nitroarene, a thiophenol, and a ketone for the synthesis of multifunctional diaryl sulfides was reported using a nitro group as the nitrogen source and thiophenol as the sulfur source. Thiophenol also serves as a proton donor to reduce nitroarene to arylamine as a key intermediate for the formation of C-N and C-S bonds. Good functional group tolerance and mild reaction conditions make this method have practical synthetic value for diversified multifunctional diaryl sulfides.

The value of serum neutralizing antibody in evaluating predictability of COVID-19 after recovery and the validation of vaccine.

BACKGROUND: This work aimed to study natural humoral immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. METHODS: Chemiluminescent immunoassay (CLIA) was used to detect the neutralizing antibody (Nabs) and IgG. RESULTS: Nabs peaked on days 57-96 after symptom onset and remained detected on days 97-132. The Nabs in the 32 patients who were dynamically monitored showed four changing patterns. The titers of Nabs and IgG were correlated, and three modes of relationship were found between them. CONCLUSIONS: Nabs showed a regular change in the course of coronavirus disease 2019 (COVID-19). The detection of Nabs is very important for monitoring the course of COVID-19 and predicting the strength of antibody protection.