Porcine reproductive and respiratory syndrome virus infection triggers autophagy via ER stress-induced calcium signaling to facilitate virus replication.

Calcium (Ca2+), a ubiquitous second messenger, plays a crucial role in many cellular functions. Viruses often hijack Ca2+ signaling to facilitate viral processes such as entry, replication, assembly, and egress. Here, we report that infection by the swine arterivirus, porcine reproductive and respiratory syndrome virus (PRRSV), induces dysregulated Ca2+ homeostasis, subsequently activating calmodulin-dependent protein kinase-II (CaMKII) mediated autophagy, and thus fueling viral replication. Mechanically, PRRSV infection induces endoplasmic reticulum (ER) stress and forms a closed ER-plasma membrane (PM) contacts, resulting the opening of store operated calcium entry (SOCE) channel and causing the ER to take up extracellular Ca2+, which is then released into the cytoplasm by inositol trisphosphate receptor (IP3R) channel. Importantly, pharmacological inhibition of ER stress or CaMKII mediated autophagy blocks PRRSV replication. Notably, we show that PRRSV protein Nsp2 plays a dominant role in the PRRSV induced ER stress and autophagy, interacting with stromal interaction molecule 1 (STIM1) and the 78 kDa glucose-regulated protein 78 (GRP78). The interplay between PRRSV and cellular calcium signaling provides a novel potential approach to develop antivirals and therapeutics for the disease outbreaks.

Role of transient receptor potential ankyrin 1 in idiopathic pulmonary fibrosis: modulation of M2 macrophage polarization.

Idiopathic pulmonary fibrosis (IPF) poses significant challenges due to limited treatment options despite its complex pathogenesis involving cellular and molecular mechanisms. This study investigated the role of transient receptor potential ankyrin 1 (TRPA1) channels in regulating M2 macrophage polarization in IPF progression, potentially offering novel therapeutic targets. Using a bleomycin-induced pulmonary fibrosis model in C57BL/6J mice, we assessed the therapeutic potential of the TRPA1 inhibitor HC-030031. TRPA1 upregulation was observed in fibrotic lungs, correlating with worsened lung function and reduced survival. TRPA1 inhibition mitigated fibrosis severity, evidenced by decreased collagen deposition and restored lung tissue stiffness. Furthermore, TRPA1 blockade reversed aberrant M2 macrophage polarization induced by bleomycin, associated with reduced Smad2 phosphorylation in the TGF-ß1-Smad2 pathway. In vitro studies with THP-1 cells treated with bleomycin and HC-030031 corroborated these findings, highlighting TRPA1's involvement in fibrotic modulation and macrophage polarization control. Overall, targeting TRPA1 channels presents promising therapeutic potential in managing pulmonary fibrosis by reducing pro-fibrotic marker expression, inhibiting M2 macrophage polarization, and diminishing collagen deposition. This study sheds light on a novel avenue for therapeutic intervention in IPF, addressing a critical need in the management of this challenging disease.

Dynamic Phase Transformations of Prussian Blue Analogue Crystals in Hydrotherms.

Prussian blue analogue (PBA)/metal-organic frameworks (MOFs) are multifunctional precursors for the synthesis of metal/metal compounds, carbon, and their derived composites (P/MDCs) in chemical, medical, energy, and other applications. P/MDCs combine the advantages of both the high specific surface area of PBA/MOF and the electronic conductivity of metal compound/carbon. Although the calcination under different atmospheres has been extensively studied, the transformation mechanism of PBA/MOF under hydrothermal conditions remains unclear. The qualitative preparation of P/MDCs in hydrothermal conditions remains a challenge. Here, we select PBA to construct a machine-learning model and measure its hydrothermal phase diagram. The architecture-activity relationship of substances among nine parameters was analyzed for the hydrothermal phase transformation of PBA. Excitingly, we established a universal qualitative model to accurately fabricate 31 PBA derivates. Additionally, we performed three-dimensional reconstructed transmission electron microscopy, X-ray absorption fine structure spectroscopy, ultraviolet photoelectron spectroscopy, in situ X-ray powder diffraction, and theoretical calculation to analyze the advantages of hydrothermal derivatives in the oxygen evolution reaction and clarify their reaction mechanisms. We uncover the unified principles of the hydrothermal phase transformation of PBA, and we expect to guide the design for a wide range of composites.

The Papain-Like Protease of Porcine Reproductive and Respiratory Syndrome Virus Impedes STING Translocation from the Endoplasmic Reticulum to the Golgi Apparatus by Deubiquitinating STIM1.

Stimulator of interferon (IFN) genes (STING) was recently pinpointed as an antiviral innate immune factor during the infection of RNA viruses. Porcine reproductive and respiratory syndrome virus (PRRSV), the swine arterivirus, is an enveloped RNA virus which has evolved many strategies to evade innate immunity. To date, the interactive network between PRRSV and STING remains to be fully established. Herein, we report that STING suppresses PRRSV replication through type I interferon signaling. However, PRRSV impedes STING trafficking from the endoplasmic reticulum (ER) to the Golgi apparatus, leading to the decreased phosphorylation of TANK-binding kinase 1 (TBK1) and interferon regulatory factor 3 (IRF3). Furthermore, PRRSV nonstructural protein 2 (Nsp2) colocalizes with STING, blocks STING translocation, and disrupts the STING-TBK1-IRF3 complex. Mechanistically, PRRSV Nsp2 retains STING at the ER by increasing the level of Ca2+ sensor stromal interaction molecule 1 (STIM1) protein. Functional analysis reveals that PRRSV Nsp2 deubiquitinates STIM1 by virtue of its papain-like protease 2 (PLP2) deubiquitinating (DUB) activity. Finally, we demonstrate that loss of STIM1 is associated with an elevated IFN response and restricts PRRSV replication. This work delineates the relationship between PRRSV infection and STING signaling and the importance of papain-like proteases (PLPs) in interfering in this axis. IMPORTANCE Porcine reproductive and respiratory syndrome virus (PRRSV), a member of the family Arteriviridae, is responsible for reproductive disorders in pregnant sows and respiratory problems in piglets, resulting in huge losses in the swine industry worldwide. Of note, PRRSV infection causes immunosuppression, of which the mechanism is not completely understood. Here, we demonstrate for the first time that STING, a protein typically associated with the antiviral response in DNA viruses, plays a critical role in controlling PRRSV infection. However, PRRSV utilizes its encoded protein Nsp2 to inhibit STING activity by blocking its translocation from the ER to the Golgi apparatus. In particular, Nsp2 retains STING at the ER by interacting with and further deubiquitinating STIM1. For this process, the activity of the viral PLP2 DUB enzyme is indispensable. The study describes a novel mechanism by which PLP2 plays a critical role in suppressing the innate immune response against arteriviruses and potentially other viruses that encode similar proteases.

OsBCAT2, a gene responsible for the degradation of branched-chain amino acids, positively regulates salt tolerance by promoting the synthesis of vitamin B5.

Salt stress negatively affects rice growth, development and yield. Metabolic adjustments contribute to the adaptation of rice under salt stress. Branched-chain amino acids (BCAA) are three essential amino acids that cannot be synthesized by humans or animals. However, little is known about the role of BCAA in response to salt stress in plants. Here, we showed that BCAAs may function as scavengers of reactive oxygen species (ROS) to provide protection against damage caused by salinity. We determined that branched-chain aminotransferase 2 (OsBCAT2), a protein responsible for the degradation of BCAA, positively regulates salt tolerance. Salt significantly induces the expression of OsBCAT2 rather than BCAA synthesis genes, which indicated that salt mainly promotes BCAA degradation and not de novo synthesis. Metabolomics analysis revealed that vitamin B5 (VB5) biosynthesis pathway intermediates were higher in the OsBCAT2-overexpressing plants but lower in osbcat2 mutants under salt stress. The salt stress-sensitive phenotypes of the osbcat2 mutants are rescued by exogenous VB5, indicating that OsBCAT2 affects rice salt tolerance by regulating VB5 synthesis. Our work provides new insights into the enzymes involved in BCAAs degradation and VB5 biosynthesis and sheds light on the molecular mechanism of BCAAs in response to salt stress.

Expression of VP2 protein of Novel goose parvovirus in baculovirus and evaluation of its immune effect.

Short-beak and dwarfism syndrome (SBDS) is a new disease caused by a genetic variant of goose parvovirus in ducks that results in enormous economic losses for the waterfowl industry. Currently, there is no commercial vaccine for this disease, so it is urgent to develop a safer and more effective vaccine to prevent this disease. In this study, we optimized the production conditions to enhance the expression of the recombinant VP2 protein and identified the optimal conditions for subsequent large-scale expression. Furthermore, the protein underwent purification via nickel column affinity chromatography, followed by concentration using ultrafiltration tube. Subsequently, it was observed by transmission electron microscopy (TEM) that the NGPV recombinant VP2 protein assembled into virus-like particles (VLPs) resembling those of the original virus. Finally, the ISA 78-VG adjuvant was mixed with the NGPV-VP2 VLPs to be prepared as a subunit vaccine. Furthermore, both agar gel precipitation test (AGP) and serum neutralization test demonstrated that NGPV VLP subunit vaccine could induce the increase of NGPV antibody in breeding ducks. The ducklings were also challenged with the NGPV, and the results showed that the maternal antibody level could provide sufficient protection to the ducklings. These results indicated that the use of the NGPV VLP subunit vaccine based on the baculovirus expression system could facilitate the large-scale development of a reliable vaccine in the future.

Pre-breeding of spontaneous Robertsonian translocations for density planting architecture by transferring Agropyron cristatum chromosome 1P into wheat.

KEY MESSAGE: We developed T1AL·1PS and T1AS·1PL Robertsonian translocations by breakage-fusion mechanism based on wheat-A. cristatum 1P(1A) substitution line with smaller leaf area, shorter plant height, and other excellent agronomic traits Agropyron cristatum, a wild relative of wheat, is a valuable germplasm resource for improving wheat genetic diversity and yield. Our previous study confirmed that the A. cristatum chromosome 1P carries alien genes that reduce plant height and leaf size in wheat. Here, we developed T1AL·1PS and T1AS·1PL Robertsonian translocations (RobTs) by breakage-fusion mechanism based on wheat-A. cristatum 1P (1A) substitution line II-3-1c. Combining molecular markers and cytological analysis, we identified 16 spontaneous RobTs from 911 F2 individuals derived from the cross of Jimai22 and II-3-1c. Fluorescence in situ hybridization (FISH) was applied to detect the fusion structures of the centromeres in wheat and A. cristatum chromosomes. Resequencing results indicated that the chromosomal junction point was located at the physical position of Triticum aestivum chromosome 1A (212.5 Mb) and A. cristatum chromosome 1P (230 Mb). Genomic in situ hybridization (GISH) in pollen mother cells showed that the produced translocation lines could form stable ring bivalent. Introducing chromosome 1PS translocation fragment into wheat significantly increased the number of fertile tillers, grain number per spike, and grain weight and reduced the flag leaf area. However, introducing chromosome 1PL translocation fragment into wheat significantly reduced flag leaf area and plant height with a negative effect on yield components. The pre-breeding of two spontaneous RobTs T1AL·1PS and T1AS·1PL was important for wheat architecture improvement.

Ursonic acid from medicinal herbs inhibits PRRSV replication through activation of the innate immune response by targeting the phosphatase PTPN1.

Porcine reproductive and respiratory syndrome (PRRS), caused by the PRRS virus (PRRSV), has caused substantial economic losses to the global swine industry due to the lack of effective commercial vaccines and drugs. There is an urgent need to develop alternative strategies for PRRS prevention and control, such as antiviral drugs. In this study, we identified ursonic acid (UNA), a natural pentacyclic triterpenoid from medicinal herbs, as a novel drug with anti-PRRSV activity in vitro. Mechanistically, a time-of-addition assay revealed that UNA inhibited PRRSV replication when it was added before, at the same time as, and after PRRSV infection was induced. Compound target prediction and molecular docking analysis suggested that UNA interacts with the active pocket of PTPN1, which was further confirmed by a target protein interference assay and phosphatase activity assay. Furthermore, UNA inhibited PRRSV replication by targeting PTPN1, which inhibited IFN-ß production. In addition, UNA displayed antiviral activity against porcine epidemic diarrhoea virus (PEDV) and Seneca virus A (SVA) replication in vitro. These findings will be helpful for developing novel prophylactic and therapeutic agents against PRRS and other swine virus infections.

Identification and evolution of non-traditional nitrilase from Spirosoma linguale DSM 74 with high hydration activity.

Hydration, a secondary activity mediated by nitrilase, is a promising new pathway for amide production. However, low hydration activity of nitrilase or trade-off between hydration and catalytic activity hinders its application in the production of amides. Here, natural C-terminal-truncated wild-type nitrilase, mined from a public database, obtained a high-hydration activity nitrilase as a novel evolutionary starting point for further protein engineering. The nitrilase Nit-74 from Spirosoma linguale DSM 74 was successfully obtained and exhibited the highest hydration activity level, performing 50.7 % nicotinamide formation and 87.6 % conversion to 2 mM substrate 3-cyanopyridine. Steric hindrance of the catalytic activity center and the N-terminus of the catalytic cysteine residue helped us identify three key residues: I166, W168, and T191. Saturation mutations resulted in three single mutants that further improved the hydration activity of N-heterocyclic nitriles. Among them, the mutant T191S performed 72.7 % nicotinamide formation, which was much higher than the previously reported highest level of 18.7 %. Additionally, mutants I166N and W168Y exhibited a 97.5 % 2-picolinamide ratio and 97.7 % isonicotinamide ratio without any loss of catalytic activity, which did not indicate a trade-off effect. Our results expand the screening and evolution library of promiscuous nitrilases with high hydration activity for amide formation.

Comprehensive transcriptome and WGCNA analysis reveals the potential function of anthocyanins in low-temperature resistance of a red flower mutant tobacco.

The anthocyanin is a protective substance in various plants, and plays important roles in resisting to low-temperature. Here, we explored transcriptome analysis of pink flower (as CK) and the natural mutant red flower (as research objects) under low-temperature conditions, and aimed to reveal the potential functions of anthocyanins and anthocyanin-related regulatory factors in resistance to low-temperature. Our results showed that most of the differentially expressed genes (DEGs) encoding key enzymes in the late stage of anthocyanin metabolism in the mutant were significantly up-regulated. Meanwhile, several genes significantly differentially expressed in CK or mutant were obtained by classification and analysis of transcription factors (TFs), phytohormones and osmoregulators. Additionally, WGCNA was carried out to mine hub genes resistanted to low-temperature stress in flavonoid pathway. Finally, one UFGT family gene, three MYB and one bHLH were obtained as the future hub genes of this study. Combined with the above information, we concluded that the ability of the red flower mutant to grow and develop normally at low-temperatures was the result of a combination of flavonoids and cold resistance genes.

The role of periodontitis in the development of atherosclerotic cardiovascular disease in participants with the components of metabolic syndrome: a systematic review and meta-analysis.

OBJECTIVES: Prevention of atherosclerotic cardiovascular disease (ASCVD) is important in individuals with metabolic syndrome components (MetS), and periodontitis may play an important role in this process. This study aims to evaluate the association between periodontitis and ASCVD in participants with the components of MetS, including obesity, dysglycemia, hypertension, and dyslipidemia. MATERIALS AND METHODS: This study conducted followed the MOOSE reporting guidelines and the PRISMA 2020 guidelines. EMBASE, MEDLINE, Web of Science, Cochrane Library, PubMed and OpenGrey were searched for observational studies about the linkage of periodontitis to ASCVD in people with MetS components up to April 9, 2023. Cohort, case-control and cross-sectional studies were included after study selection. Quality evaluation was carried out using the original and modified Newcastle-Ottawa Scale as appropriate. Random-effects model was employed for meta-analysis. RESULTS: Nineteen studies were finally included in the quality analysis, and all of them were assessed as moderate to high quality. Meta-analyses among fifteen studies revealed that the participants with periodontitis were more likely to develop ASCVD in those who have dysglycemia (RR = 1.25, 95% CI = 1.13-1.37; p < 0.05), obesity (RR = 1.13, 95% CI = 1.02-1.24; p < 0.05), dyslipidemia (RR = 1.36, 95% CI = 1.13-1.65; p < 0.05), or hypertension (1.20, 95% CI = 1.05-1.36; p < 0.05). CONCLUSIONS: Periodontitis promotes the development of ASCVD in participants with one MetS component (obesity, dysglycemia, hypertension or dyslipidemia). CLINICAL RELEVANCE: In people with MetS components, periodontitis may contribute to the ASCVD incidence.

Synergistic Effect of Oxygen Vacancy and High Porosity of Nano MIL-125(Ti) for Enhanced Photocatalytic Nitrogen Fixation.

This work reports that a low-temperature thermal calcination strategy was adopted to modulate the electronic structure and attain an abundance of surface-active sites while maintaining the crystal morphology. All the experiments demonstrate that the new photocatalyst nano MIL-125(Ti)-250 obtained by thermal calcination strategy has abundant Ti3+ induced by oxygen vacancies and high specific surface area. This facilitates the adsorption and activation of N2 molecules on the active sites in the photocatalytic nitrogen fixation. The photocatalytic NH3 yield over MIL-125(Ti)-250 is enhanced to 156.9 µmol g-1 h-1 , over twice higher than that of the parent MIL-125(Ti) (76.2 µmol g-1 h-1 ). Combined with density function theory (DFT), it shows that the N2 adsorption pattern on the active sites tends to be from "end-on" to "side-on" mode, which is thermodynamically favourable. Moreover, the electrochemical tests demonstrate that the high atomic ratio of Ti3+ /Ti4+ can enhance carrier separation, which also promotes the efficiency of photocatalytic N2 fixation. This work may offer new insights into the design of innovative photocatalysts for various chemical reduction reactions.

A New Long Noncoding RNA, MAHAT, Inhibits Replication of Porcine Reproductive and Respiratory Syndrome Virus by Recruiting DDX6 To Bind to ZNF34 and Promote an Innate Immune Response.

Long noncoding RNAs (lncRNAs) have increasingly been recognized as being integral to cellular processes, including the antiviral immune response. Porcine reproductive and respiratory syndrome virus (PRRSV) is costly to the global swine industry. To identify PRRSV-related lncRNAs, we performed RNA deep sequencing and compared the profiles of lncRNAs in PRRSV-infected and uninfected Marc-145 cells. We identified a novel lncRNA called MAHAT (maintaining cell morphology-associated and highly conserved antiviral transcript; LTCON_00080558) that inhibits PRRSV replication. MAHAT binds and negatively regulates ZNF34 expression by recruiting and binding DDX6, an RNA helicase forming a complex with ZNF34. Inhibition of ZNF34 expression results in increased type I interferon expression and decreased PRRSV replication. This finding reveals a novel mechanism by which PRRSV evades the host antiviral innate immune response by downregulating the MAHAT-DDX6-ZNF34 pathway. MAHAT could be a host factor target for antiviral therapies against PRRSV infection. IMPORTANCE Long noncoding RNAs (lncRNAs) play important roles in viral infection by regulating the transcription and expression of host genes, and interferon signaling pathways. Porcine reproductive and respiratory syndrome virus (PRRSV) causes huge economic losses in the swine industry worldwide, but the mechanisms of its pathogenesis and immunology are not fully understood. Here, a new lncRNA, designated MAHAT, was identified as a regulator of host innate immune responses. MAHAT negatively regulates the expression of its target gene, ZNF34, by recruiting and binding DDX6, an RNA helicase, forming a complex with ZNF34. Inhibition of ZNF34 expression increases type I interferon expression and decreases PRRSV replication. This finding suggests that MAHAT has potential as a new target for developing antiviral drugs against PRRSV infection.

Marinihelvus fidelis gen. nov., sp. nov., isolated from marine sediment, and genomic comparison with multiple genera.

A Gram-stain-negative, rod-shaped, non-gliding, non-flagellated, yellow, facultatively aerobic bacterial strain, designated as W260T, was isolated from marine sediment of Xiaoshi Island, Weihai, PR China. The cells of W260T were 0.3-0.5 µm wide and 1.5-2.0 µm long. Strain W260T grows optimally at a temperature of 33 °C (range, 15-37 °C), pH 8 (range, pH 6.5-9.5) and witha NaCl concentration of 3.0 % (w/v; range, 1-8 %). It has the highest sequence similarity to Thiohalobacter thiocyanaticus DSM 21152T (91.7 %), followed by Wenzhouxiangella marina MCCC 1K00261T (91.4 %) and Thiohalospira alkaliphila DSM 17116T (90.7 %). The similarity between strain W260T and the species Thiohalophilus thiocyanatoxydans DSM 16326T was 89.4 %. Genome sequencing revealed a genome size of 3 430 000 bp and a DNA G+C content of 64.5 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between strain W260T and W. marina MCCC 1K00261T were 69.6 and 16.1-20.6 %, respectively. The predominant quinone was ubiquitin-8, and the major fatty acids were iso-C14 : 0 and iso-C16 : 0. The polar lipids consisted of phosphatidylethanolamine, phospholipid, phosphatidylglycerol, diphosphatidylglycerol and four unidentified lipids. Based on phenotypic, phylogenetic and chemotaxonomic information, it was determined that strain W260T represents a novel genus and species and it was given the name Marinihelvus fidelis sp. nov. The type strain is W260T (=MCCC 1H00471T=KCTC 92639T).

Vidofludimus inhibits porcine reproductive and respiratory syndrome virus infection by targeting dihydroorotate dehydrogenase.

Porcine reproductive and respiratory syndrome virus (PRRSV) infection has caused huge economic losses in global swine industry over the last 37 years. PRRSV commercial vaccines are not effective against all epidemic PRRSV strains. In this study we performed a high-throughput screening (HTS) of an FDA-approved drug library, which contained 2339 compounds, and found vidofludimus (Vi) could significantly inhibits PRRSV replication in Marc-145 cells and primary porcine alveolar macrophages (PAMs). Compounds target prediction, molecular docking analysis, and target protein interference assay showed that Vi interacts with dihydroorotate dehydrogenase (DHODH), a rate-limiting enzyme in the de novo pyrimidine synthesis pathway. Furthermore, PRRSV infection was restored in the presence of excess uridine and cytidine which promote pyrimidine salvage, or excess orotate which is the product of DHODH in the de novo pyrimidine biosynthesis pathway, thus confirming that the antiviral effect of Vi against PRRSV relies on the inhibition of DHODH. In addition, Vi also has antiviral activity against Seneca virus A (SVA), encephalomyocarditis virus (EMCV), porcine epidemic diarrhea virus (PEDV), and pseudorabies virus (PRV) in vitro. These findings should be helpful for developing a novel prophylactic and therapeutic strategy against PRRSV and other swine viral infections.

Analysis of clinical characteristics and risk factors of community-acquired pneumonia complicated by parapneumonic pleural effusion in elderly patients.

BACKGROUND: Community-acquired pneumonia (CAP) patients usually present with parapneumonic pleural effusion (PPE), which complicates the treatment of pneumonia. This study aims to investigate the clinical characteristics and risk factors of elderly CAP patients hospitalised with PPE. METHODS: The clinical data of 132 elderly patients with CAP were retrospectively analysed. A total of 54 patients with PPE (PPE group) and 78 patients without PPE (NPPE group) were included in this study. Clinical data, laboratory examinations, treatments and other relevant indicators were collected. Univariate analysis and multivariate logistic regression analysis will be used to explore the possible risk factors for PPE. RESULTS: The proportion of PPE in elderly patients with CAP was 40.9%. PPE patients were significantly more likely to be older, have comorbid neurological diseases, experience chest tightness, and have a lasting fever (P < 0.05). In contrast to NPPE patients, the total number of lymphocytes, serum albumin and blood sodium levels in the PPE group were significantly lower (P < 0.05). The blood D-dimer, C-reactive protein and CURB-65 score of PPE patients were significantly higher (P < 0.05) than those of NPPE patients. Multivariate logistic regression identified chest tightness (OR = 3.964, 95% CI: 1.254-12.537, P = 0.019), long duration of fever (OR = 1.108, 95%CI: 1.009-1.217, P = 0.03), low serum albumin (OR = 0.876, 95%CI: 0.790- 0.971, P = 0.012) or low blood sodium (OR = 0.896, 95%CI: 0.828-0.969, P = 0.006) as independently associated with the development of parapneumonic pleural effusion in the elderly. CONCLUSION: This study has identified several clinical factors, such as chest tightness, long duration of fever, low serum albumin, and low blood sodium, as risk factors for the development of pleural effusion in elderly patients with CAP. Early identification and prompt management of these patients can prevent inappropriate treatment and reduce morbidity and mortality.

Damage Analysis of Segmental Dry Joint Full-Scale Prestressed Cap Beam Based on Distributed Optical Fiber Sensing.

Distributed fiber optic sensors (DFOS) can detect structural cracks and structural deformation with high accuracy and wide measurement range. This study monitors the segmental prestressed bent cap, assembled with a large key dry joint, based on optical fiber technology, and it allows the comparison of its damaging process with that of a monolithic cast in place counterpart. The obtained results, comprising cross-section strain distributions, longitudinal strain profiles, neutral axis location, crack pattern, and the damage process, show that the DFOS technology can be successfully used to analyze the complex working stress state of the segmental beam with shear key joints, both in the elastic range and at the ultimate load, and to successfully identify the changing characteristics of the stress state of the segmental capping beam model when elastic beam theory no longer applies. The DFOS data confirm that the shear key joint, as the weak point of the segmental cap beam, results in the high stress concentration area, and the damage rate is higher than that of the cast-in-place beam. The accurate monitoring by the DFOS allows for the realization that the damage occurs at the premature formation of a concentrated compression zone on the upper part of the shear key.

The characteristic of the key aroma-active components in white tea using GC-TOF-MS and GC-olfactometry combined with sensory-directed flavor analysis.

BACKGROUND: White tea has become more and more popular with consumers due to its health benefits and unique flavor. However, the key aroma-active compounds of white tea during the aging process are still unclear. Thus, the key aroma-active compounds of white tea during the aging process were investigated using gas chromatography-time-of-flight-mass spectrometry (GC-TOF-MS) and gas chromatography-olfactometry (GC-O) combined with sensory-directed flavor analysis. RESULTS: A total of 127 volatile compounds were identified from white tea samples with different aging years by GC-TOF-MS. Fifty-eight aroma-active compounds were then determined by GC-O, and 19 of them were further selected as the key aroma-active compounds based on modified frequency (MF) and odor activity value (OAV). CONCLUSION: Aroma recombination and omission testing confirmed that 1-octen-3-ol, linalool, phenethyl alcohol, geraniol, (E)-ß-ionone, α-ionone, hexanal, phenylacetaldehyde, nonanal, (E, Z)-(2,6)-nonadienal, safranal, γ-nonalactone and 2-amylfuran were the common key aroma-active compounds to all samples. Cedrol, linalool oxide II and methyl salicylate were confirmed peculiar in new white tea, while ß-damascenone and jasmone were peculiar in aged white tea. This work will offer support for further studies on the material basis of flavor formation of white tea. © 2023 Society of Chemical Industry.

Converting Non-strained γ-Valerolactone and Derivatives into Sustainable Polythioesters via Isomerization-driven Cationic Ring-Opening Polymerization of Thionolactone Intermediate.

This contribution reports the efficient conversion of γ-valerolactone and its derivatives, abundant but unexplored renewable feedstocks, into sustainable and degradable polythioesters via the establishment of the first isomerization-driven ring-opening polymerizations (IROPs) of corresponding thionolactone intermediates. The key to this success relies on the development of a new simple and robust [Et3 O]+ [B(C6 F5 )4 ]- cationic initiator which possesses high activity, exclusive selectivity, living nature, and broad scope of thionolactones. A complete inversion of configuration during IROP of enantiopure γ-thionovalerolactone is also disclosed, affording isotactic semicrystalline polythioesters (Tm =87.0 °C) with mechanical property compared well to the representative commodity polyolefins. The formation of a highly crystalline supramolecular stereocomplex with enhanced thermal property (Tm =117.6 °C) has also been revealed.

2D MOF-assisted Pyrolysis-displacement-alloying Synthesis of High-entropy Alloy Nanoparticles Library for Efficient Electrocatalytic Hydrogen Oxidation.

Multimetallic alloy nanoparticles (NPs) have received considerable attention in various applications due to their compositional variability and exceptional properties. However, the complexity of both the general synthesis and structure-activity relationships remain the long-standing challenges in this field. Herein, we report a versatile 2D MOF-assisted pyrolysis-displacement-alloying route to successfully synthesize a series of binary, ternary and even high-entropy NPs that are uniformly dispersed on porous nitrogen-doped carbon nanosheets (PNC NSs). As a proof of utility, the obtained Co0.2 Ru0.7 Pt0.1 /PNC NSs exhibits apparent hydrogen oxidation activity and durability with a record-high mass specific kinetic current of 1.84 A mg-1 at the overpotential of 50 mV, which is approximately 11.5 times higher than that of the Pt benchmark. Both experimental and theoretical studies reveal that the addition of Pt engenders a phase transition in CoRu alloys from hexagonal close-packed (hcp) to face-centered cubic (fcc) structure. The elevated reactivity of the resulted ternary alloy can be attributed to the optimized adsorption of hydrogen intermediate and the decreased reaction barrier for water formation. This study opens a new avenue for the development of highly efficient alloy NPs with various compositions and functions.