Iridium-Catalyzed Enantioselective Propargylic C-H Trifluoromethylthiolation and Related Processes.

The trifluoromethylthio group (SCF3) has gained increasing prominence in the field of drug design and development due to its unique electronic properties, remarkable stability, and high lipophilicity, but its derivatives remain challenging to access, especially in an enantioselective manner. In this Communication, we present an enantioselective iridium-catalyzed trifluoromethylthiolation of the propargylic C(sp3)-H bonds of alkynes. This protocol demonstrates its efficacy across a diverse array of alkyne substrates, including B- and Si-protected terminal alkynes as well as those derived from natural products and pharmaceuticals, to give trifluoromethyl thioethers with good to excellent yield and stereoselectivity. Moreover, this protocol could be modified to access enantioenriched difluoromethyl and chlorodifluoromethyl thioethers (SCF2H and SCF2Cl derivatives), significantly expanding the space of synthetically accessible enantioenriched fluoroorganic compounds.

Study on the expression and prognostic relationship of MYL6B in liver cancer based on bioinformatics.

BACKGROUND: Primary liver cancer is a prevalent and deadly cancer type. Despite treatment advances, prognosis remains poor, with high recurrence rates. Early detection is crucial but challenging due to the disease's insidious nature. Myosin proteins play significant roles in cancer development, influencing cell migration, invasion, and tumor suppression. MYL6B, a myosin light chain, is involved in various cellular processes and has been associated with poor prognosis in colorectal adenocarcinoma and potential as a biomarker in breast cancer. AIM: To investigate the expression of MYL6B in liver hepatocellular carcinoma (LIHC) and its impact on prognosis and potential mechanisms of action using bioinformatics methods. METHODS: The expression of MYL6B in pan-cancer and normal tissues was analyzed using the gene expression profiling interactive analysis 2 and tumor immune estimation resource databases. The expression level of MYL6B in LIHC tissues and its relationship with prognosis were analyzed, immunohistochemical analysis of MYL6B and its effect on immune cell infiltration, and the protein network were further studied. RESULTS: MYL6B was highly expressed in diffuse large b-cell lymphoma, LIHC, pancreatic adenocarcinoma, skin cutaneous melanoma, thymoma, uterine corpus endometrial carcinoma, uterine carcinosarcoma, and lowly expressed in kidney chromophobe, acute myeloid leukemia, testicular germ cell tumors. The expression level of MYL6B was significantly different between cancer and normal tissues. It had a significant impact on both overall survival and disease-free survival. MYL6B is highly expressed in hepatocellular carcinoma and its expression level increases with cancer progression. High MYL6B expression is associated with poor prognosis in terms of overall survival and recurrence-free survival. The immunohistochemical level of MYL6B is high in hepatocellular carcinoma tissues, and MYL6B has a high level of immune infiltration inflammation. In protein network analysis, MYL6B is correlated with MYL2, MYL6, MYL9, MYLK4, MYLK2, MYL12A, MYL12B, MYH11, MYH9 and MYH10. CONCLUSION: The expression level of MYL6B in LIHC was significantly higher than in normal liver tissues, and it was correlated with the degree of differentiation survival rate, and immune infiltration. MYL6B is a potential target for LIHC treatment.

Positively Photo-Responsive Adsorption Over Binary Copper Porphyrin Framework and Graphene Film Sorbents.

Photo-responsive adsorption has emerged as a vibrant area because it provides a promising route to reduce the energy consumption of the traditional adsorption separation. However, the current methodology to fabricate photo-responsive sorbents is still subject to the photo-deforming molecular units. In this study, a new initiative of photo-dissociated electron-hole pairs is proposed to generate amazing adsorption activity, and prove its feasibility. Employing CuPP [PP = 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin] framework nanosheets compounded with graphene, binary film (BF) sorbents are successfully fabricated. The paradigmatic BF nanostructure brings about efficiently photo-excited electron-hole pairs with durable enough lifetime to meet the needs of microscopic adsorption equilibrium, which ultimately alters the electron density distribution of adsorption surface, and thus markedly modulates the adsorption activity. Therefore, an amazing photo-enhanced adsorption capability for the index gas CO can be gotten. Once exposed to the visible-light at 420 nm, the CO adsorption capacity (0 °C, 1 bar) is risen from 0.23 mmol g-1 in the darkness to 1.66 mmol g-1, changed by + 622%. This is essentially different from majority of current photo-responsive sorbents based on photo-deforming molecular units, of which adsorption capability is only decreased with photo-induction, and the maximum rate of change reported is just -54%.

COVID-19 and Contraceptive Use in Two African Countries: Examining Conflicting Pressures on Women.

Women in Africa may have experienced conflicting pressures during the COVID-19 pandemic. While the unpredictable nature of the pandemic was prompting some women to delay pregnancies, the pandemic was potentially limiting access to reproductive health services due to supply shortages, fears of virus exposure, and mobility restrictions. In this study, we used longitudinal data from Kenya and Burkina Faso and applied a multilevel perspective to better understand the factors contributing to change or persistence in contraceptive use during the early months of the pandemic. We found a marginal increase in contraceptive uptake in the early days of the pandemic. Multilevel logistic regression results revealed that interpersonal trust and accurate knowledge of COVID-19 precautions were associated with a greater likelihood of initiating contraception. These factors appeared to have provided women with confidence to navigate the complicated COVID-19 landscape. At the same time, we observed a decrease in contraceptive use in regions with high COVID-19 cases, suggesting the virus was limiting access to contraception in some contexts. These findings highlighted the need for public health officials to ensure that women have the necessary knowledge and ability to safely access contraception during public health crises, when overall demand for contraception may be increasing.

Neighborhood social cohesion and physical disorder in relation to social isolation in older adults: racial and ethnic differences.

BACKGROUND: Neighborhood factors of social isolation have been understudied, hindering efforts to reduce social isolation at the neighborhood level. This study aims to investigate the longitudinal effects of neighborhood social cohesion and physical disorder on social isolation in community-dwelling older adults, as well as to examine whether race/ethnicity moderates the neighborhood-isolation relationship. METHODS: We used 11-year data from the National Health and Aging Trend Study, a longitudinal national study of Medicare beneficiaries aged 65 and older. Social isolation was measured through a summary score across four domains: marital/partner status, family and friend contact, religious attendance, and club participation. A series of weighted mixed-effects logistic regression models were performed to test the study aims. Sample sizes ranged from 7,303 to 7,291 across individual domains of social isolation. RESULTS: Approximately 20% of participants reported social isolation. Findings indicated a negative association between neighborhood social cohesion and social isolation. Higher levels of neighborhood social cohesion were longitudinally associated with lower odds of social isolation (odds ratio [OR] = 0.52, 95% CI: 0.47-0.58). Yet, the presence of neighborhood physical disorder was associated with an increased risk of overall social isolation ([OR] = 1.2, 95% CI: 1.00, 1.44). Race/ethnicity significantly moderated the effects of neighborhood social cohesion and physical disorder on social isolation. The odds of no in-person visits associated with neighborhood social cohesion are smaller among Black adults compared to White adults. Black adults had constantly lower odds of isolation from religious attendance compared to White adults regardless of the level of neighborhood social cohesion. Hispanic adults had decreased odds of having no friends associated with signs of physical disorder, while no associations were found among older White adults. White adults had higher odds of isolation from in-person visits when living in neighborhoods with signs of physical disorder, whereas no association was observed among older Black and Hispanic adults. CONCLUSIONS: This study elucidates the role of neighborhood characteristics in shaping social isolation dynamics among older adults. Furthermore, the observed moderation effects of race/ethnicity suggest the need for culturally sensitive interventions tailored to address social isolation within specific neighborhood and racial contexts.

Lipid-lowering effects of gefarnate in statin-treated patients with residual hypertriglyceridemia: a randomized controlled study.

BACKGROUND: The prevention of coronary artery disease (CAD) faces dual challenges: the aspirin-induced gastrointestinal injury, and the residual cardiovascular risk after statin treatment. Geraniol acetate (Gefarnate) is an anti-ulcer drug. It was reported that geraniol might participate in lipid metabolism through a variety of pathways. The aim of this study was to assess the lipid-lowering effects of gefarnate in statin-treated CAD patients with residual hypertriglyceridemia. METHODS: In this prospective, open-label, randomized, controlled trial, 69 statin-treated CAD patients with residual hypertriglyceridemia were randomly assigned to gefarnate group and control group, received gefarnate (100 mg/3 times a day) combined with statin and statin alone, respectively. At baseline and after one-month treatment, the levels of plasma triglyceride, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and total cholesterol were tested. RESULTS: After one-month gefarnate treatment, triglyceride level was significantly lowered from 2.64 mmol/L to 2.12 mmol/L (P = 0.0018), LDL-C level lowered from 2.7 mmol/L to 2.37 mmol/L (P = 0.0004), HDL-C level increased from 0.97 mmol/L to 1.17 mmol/L (P = 0.0228). Based on statin therapy, gefarnate could significantly reduce the plasma triglyceride level (P = 0.0148) and increase the plasma HDL-C level (P = 0.0307). Although the LDL-C and total cholesterol levels tended to decrease, there was no statistically significant difference. CONCLUSIONS: The addition of gefarnate to statin reduced triglyceride level and increased HDL-C level to a significant extent compared to statin alone in CAD patients with residual hypertriglyceridemia. This suggested that gefarnate might provide the dual benefits of preventing gastrointestinal injury and lipid lowering in CAD patients.

Urine Metabolites Changes in Acute Myocardial Infarction Rats via Metabolomic Analysis.

OBJECTIVES: To screen biomarkers for forensic identification of acute myocardial infarction (AMI) by non-targeted metabolomic studies on changes of urine metabolites in rats with AMI. METHODS: The rat models of the sham surgery group, AMI group and hyperlipidemia + acute myocardial infarction (HAMI) group were established. Ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS) was used to analyze the changes of urine metabolic spectrometry in AMI rats. Principal component analysis, partial least squares-discriminant analysis, and orthogonal partial least squares-discriminant analysis were used to screen differential metabolites. The MetaboAnalyst database was used to analyze the metabolic pathway enrichment and access the predictive ability of differential metabolites. RESULTS: A total of 40 and 61 differential metabolites associated with AMI and HAMI were screened, respectively. Among them, 22 metabolites were common in both rat models. These small metabolites were mainly concentrated in the niacin and nicotinamide metabolic pathways. Within the 95% confidence interval, the area under the curve (AUC) values of receiver operator characteristic curve for N8-acetylspermidine, 3-methylhistamine, and thymine were greater than 0.95. CONCLUSIONS: N8-acetylspermidine, 3-methylhistamine, and thymine can be used as potential biomarkers for AMI diagnosis, and abnormal metabolism in niacin and nicotinamide may be the main causes of AMI. This study can provide reference for the mechanism and causes of AMI identification.

Performance analysis of non-invasive prenatal testing for trisomy 13, 18, and 21: A large-scale retrospective study (2018-2021).

Background: Non-invasive prenatal tests (NIPT) are used to screen for trisomy 21, 18, and 13. This study investigated NIPT performance and the clinical significance of its results. Methods: Pregnant women (n = 282,911) participating in a free NIPT (April 2018-December 2021) were screened for common trisomies, and the results were retrospectively analyzed. NIPT performance was evaluated by its positive predictive value (PPV), sensitivity, and specificity. Results were analyzed using number, percentage, and chi-squared/t-test analyses. Results: After NIPT screening, patients with common trisomies (n = 746) included 457 with T21, 160 with T18, and 129 with T13. Seven false negative cases were identified. High PPV (86.81 %, 56.81 %, 18.18 %), sensitivity (99.25 %, 98.33 %, 100.00 %), and specificity (99.98 %, 99.98 %, 99.97 %) values were detected for trisomy 21, 18, and 13, respectively. The PPVs of common trisomies were significantly different between pregnant women older than 35 (85.53 %, 136/159) and those aged 35 or younger (58.90 %, 311/528) (χ2 = 125.02, P = 2.20e-16). As the NIPT uptake increased from 2018 to 2021, live-born birth defect incidence decreased. Conclusion: NIPT performed well in screening for T21, T18, and T13. Our discoveries offer an important and useful guideline in laboratory and clinical genetic counseling.

[Widely targeted metabolomics reveals differential metabolites between root tuber and leaf of Fallopia multiflora].

This study aims to reveal the differences in the species and relative content of metabolites in the leaf and root tuber of Fallopia multiflora and improve the comprehensive utilization rate of F. multiflora resources. The metabolites in the root tubers and leaves of F. multiflora were detected by widely targeted metabolomics based on ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS). The principal component analysis, hierarchical cluster analysis, and orthogonal partial least squares-discriminant analysis were carried out to screen the differential metabolites between the leaf and root tuber of F. multiflora. The result showed that a total of 1 942 metabolites in 15 categories were detected in the leaf and root tuber of F. multiflora, including 1 861 metabolites in the root tuber, 1 901 metabolites in the leaf, and 1 820 metabolites in both. The metabolites were mainly phenolic acids, flavonoids, amino acids and derivatives, and alkaloids. A total of 1 200 differential metabolites were screened out, accounting for 65.9% of the total metabolites. Among these differential metabolites, 813 and 387 showed higher content in the leaf and root tuber, respectively. Flavonoids were the metabolites with the largest number and the most significant differences between the leaf and root tuber, and stilbenes and anthraquinones as the main active compounds mainly existed in the root tuber. The KEGG enrichment results suggested that the differential metabolites were mainly enriched in flavonoid and flavonol biosynthesis pathways and linoleic acid metabolism pathway. This study discovered abundant metabolites in F. multiflora. The metabolites were similar but had great differences in the content between the leaf and root tuber. The research results provide theoretical guidance for the development and utilization of F. multiflora resources.

A Taxonomic Study of Candolleomyces Specimens from China Revealed Seven New Species.

Based on phylogenetic analysis, Candolleomyces (Psathyrellaceae, Agaricales) was established with Psathyrella candolleana as the type species. The basidiomes range from small to large and are typically terrestrial, lignicolous, and rarely fimicolous. We analysed the Candolleomyces species collected during five years in China, and based on morphological and molecular data (nrITS, nrLSU, and tef-1α), we propose seven new Candolleomyces species viz. C. brevisporus, C. gyirongicus, C. lignicola, C. luridus, C. shennongdingicus, C. shennongjianus, and C. sichuanicus. Full descriptions, colour photographs, illustrations, phylogenetic analyses results, and comparisons with related Candolleomyces species of the new taxa are provided. This study enriches the species diversity of Candolleomyces in China.

Temporal and Racial/Ethnic Patterns of Social Engagement among Older Adults: Evidence from American Time Use Survey 2019 to 2022.

This study examines temporal and racial/ethnic patterns in social engagement among older adults from 2019 to 2022, using data from the American Time Use Survey (ATUS) for adults aged 60 and older (n = 13,605). Social engagement was operationalized as time spent on five activities in in-home and out-of-home settings. Descriptive analysis was used to characterize temporal trends of social engagement, and zero-inflated negative binomial regression was utilized to estimate year-specific racial/ethnic differences. Results indicate an initial decline in out-of-home social engagement, followed by a gradual recovery. Racial differences in social engagement became salient during the pandemic period. The evolving racial and ethnic patterns in social engagement underscore the challenges that Black and Hispanic older adults faced during the public health crisis. Understanding activity patterns specific to racial/ethnic groups has implications for targeted interventions, informing strategies to support Black, Hispanic, and other minoritized older adults in public health emergencies.

A robust triphenylamine-based monolithic polymer network for selective sieving of CO2 and PM from flue gas.

The increasingly urgent issue of climate change is driving the development of carbon dioxide (CO2) capture and separation technologies in flue gas after combustion. The monolithic adsorbent stands out in practical adsorption applications for its simplified powder compaction process while maintaining the inherent balance between energy consumption for regeneration and selectivity for adsorption. However, optimizing the adsorption capacity and selectivity of CO2 separation materials remains a significant challenge. Herein, we synthesized monolithic polymer networks (N-CMPs) with triphenylamine adsorption sites, acid-base environment tolerance, and precise narrow microchannel pore systems for the selective sieving of CO2 and particulate matter (PM) in flue gas. The inherent continuous covalent bonding of N-CMPs, along with their highly delocalized π-π conjugated porous framework, ensures the stability of the monolithic polymer network's adsorption and separation capabilities under wet and acid-base conditions. Specifically, under the conditions of 1 bar at 273 K, the CO2 adsorption capacity of N-CMP-1 is 3.35 mmol/g. Attributed to the highly polar environment generated by triphenylamine and the inherent high micropore/mesopore ratio, N-CMPs exhibit an excellent ideal adsorbed solution theory (IAST) selectivity for CO2/N2 under simulated flue gas conditions (CO2/N2 = 15:85). Dynamic breakthrough experiments further visualize the high separation efficiency of N-CMPs in practical adsorption applications. Moreover, under acid-base conditions, N-CMPs achieve a capture efficiency exceeding 99.76 % for PM0.3, enabling the selective separation of CO2 and PM in flue gas. In fact, the combined capture of hazardous PM and CO2 from the exhaust gases produced by the combustion of fossil fuels will play a pivotal role in mitigating climate change and environmental issues until low-carbon and alternative energy technologies are widely adopted.

Recent advances in palladium-catalyzed sulfonylation via SO2 insertion.

The importance of sulfonyl-group-containing compounds, such as sulfonamides, sulfones, sulfinate esters, and sulfonyl fluorides, in pharmaceuticals, bioactive molecules, and natural products cannot be overstated. The new development of palladium-catalyzed sulfonylation via SO2 insertion represents a crucial advancement in organic synthesis, enabling the direct α,α-difunctionalization of SO2 and providing efficient access to an array of structure-diverse sulfonyl-containing compounds. Although there have been numerous reviews about SO2 insertion, many of them only cover specific aspects of palladium-catalyzed reactions, leading to an oversight of some important works. Besides, these reviews often lack detailed discussions and systematic conclusion on reaction mechanisms, and fail to comprehensively summarize the significant research achievements in palladium-catalyzed reactions over the past few years. Herein, we aim to systematically consolidate the recent advances in palladium-catalyzed sulfonylation via SO2 insertion, elucidate the underlying reaction mechanism, and highlight some unsolved challenges in this segment. This review seeks to serve as a valuable resource for researchers, assisting in the continued development of palladium-catalyzed sulfonylation methodologies.

Effects of ferroptosis-related gene HSPB1 on acute myeloid leukemia.

INTRODUCTION: The purpose of this study was to investigate the effects and potential mechanisms of ferroptosis-related gene heat shock protein beta-1 (HSPB1) on acute myeloid leukemia (AML). METHODS: The RNA-seq and clinical data of AML samples were obtained from the Genomic Data Commons database, and the FerrDb database was used to screen the marker, drive and suppressor of ferroptosis. Besides, DESeq2 was applied for differential expression analysis on AML samples and screening for differentially expressed genes (DEGs). The screened DEGs were subjected to the intersection analysis with ferroptosis-related genes to identify the ferroptosis-related DEGs. Next, the functional pathways of ferroptosis-related DEGs were further be discussed by Gene Ontology as well as Kyoto Encyclopedia of Genes and Genomes enrichment analysis of DEGs. Additionally, lasso regression analysis was employed to determine the differential genes related to prognosis in patients with AML and the survival analysis was performed. Subsequently, quantitative real-time polymerase chain reaction and western blot assay were applied to detect the mRNA and protein expression levels of HSPB1 in normal/AML bone marrow tissues and human normal (HS-5)/AML (HL-60) bone marrow cells, respectively. Furthermore, HSPB1 was knocked down to assess the expression changes of glutathione peroxidase 4 and acyl-CoA synthetase long-chain family member 4. Ultimately, the viability and oxidative stress levels of HL-60 were analyzed by Cell Counting Kit-8 and biochemical detection. RESULTS: A total of 4986 DEGs were identified in AML samples, with 3324 up-regulated and 1662 down-regulated. The enrichment analysis illustrated that ferroptosis-related DEGs were significantly enriched in response to metal irons, oxidative stress, and other pathways. After lasso regression analysis, 17 feature genes related to the prognosis of patients with AML were obtained, with HSPB1 exhibiting a significant correlation. The reliability of our models was verified by Cox regression analysis and survival analysis of the hazard model. Furthermore, the outcomes of quantitative real-time polymerase chain reaction and western blot showed that mRNA and protein expression levels of HSPB1 were significantly increased in the AML Group and HL-60 cells. The knockdown of HSPB1 in HL-60 cells reduced the protein level of glutathione peroxidase 4, increased the protein level of acyl-CoA synthetase long-chain family member 4, decreased the cell viability, and aggravated oxidative stress. CONCLUSION: Ferroptosis-related gene HSPB1 is highly expressed in patients with AML. In addition, HSPB1 may be involved in the occurrence and development of AML by regulating oxidative stress and ferroptosis-related pathways. This study provides new clues for further understanding of AML molecular mechanisms. Also, HSPB1 is expected to be a potential therapeutic target for AML in the future.

[Effects of water-nitrogen interactions on NH3 and N2O emissions and yield in winter wheat cropland]. / 水氮互作对冬小麦农田NH3和N2O排放及产量的影响.

To investigate the effects of different irrigation and nitrogen application modes on nitrogen gaseous loss in winter wheat farmland, we conducted a field experiment at Changqing Irrigation Experiment Station in Shandong Province, with two irrigation levels (80%-90% θf(I1) and 70%-80% θf(I2)) and three nitrogen application levels (conventional nitrogen application of 240 kg·hm-2(N1), nitrogen reduction of 12.5% (N2), and nitrogen reduction of 25% (N3)). The results showed that ammonia volatilization and nitrous oxide emission rate peak appeared within 2-4 days after fertilization or irrigation. The ammonia volatilization rate during the chasing fertilizer period was significantly higher than that during the basal fertilizer period. Compared with other treatments, the ave-rage ammonia volatilization rate of I2N2 treatment during the chasing fertilizer period was reduced by 10.1%-51.6%, and the average nitrous oxide emission rate over the whole growth period was reduced by 15.4%-52.2%. The ammonia volatilization rate was significantly positively associated with surface soil pH value and ammonium nitrogen content, while the nitrous oxide emission rate was significantly positively associated with nitrate content in topsoil. The accumulation amount of soil ammonia volatilization and nitrous oxide emission ranged from 0.83-1.42 and 0.11-0.33 kg·hm-2, respectively. Moderate reduction of irrigation water and nitrogen input could effectively reduce cumulative amounts of ammonia volatilization and nitrous oxide emission from winter wheat farmland. The cumulative amounts of ammonia volatilization and nitrous oxide emission under I1N3 and I2N2 treatments were signi-ficantly lower than those under other treatments. The highest winter wheat yield (5615.6 kg·hm-2) appeared in I2N2 treatment. The irrigation water utilization efficiency of I2 was significantly higher than that of I1, with the maximum increase rate of 45.2%. Compared with N1 and N3 treatments, the maximum increase rate of nitrogen fertilizer productivity and agricultural utilization efficiency in N2 reached 15.2% and 31.8%, respectively. In conclusion, the treatment with 70%-80% θf irrigation level and 210 kg·hm-2 nitrogen input could effectively improve the utilization efficiency of irrigation water and nitrogen fertilization and reduce gaseous loss from winter wheat farmland.

Bisphenol S exposure induces intestinal inflammation via altering gut microbiome.

Bisphenol S (BPS), a substitute for bisphenol A, is widely used in the manufacture of food packaging materials, raising concern over its toxicity. However, evidence is still lacking on whether gut microbiota involved in BPS induced intestinal inflammation in mammals, as well as its underlying mechanism. Using mouse BPS exposure model, we found intestinal inflammation characterized by shortened colon length, crypt distortion, macrophage accumulation and increased apoptosis. As for gut microbiota, 16s rRNA gene amplicon sequencing showed BPS exposure induced gut dysbiosis, including increased pro-inflammatory microbes such as Ileibacterium, and decreased anti-inflammatory genera such as Lactobacillus, Blautia and Romboutsia. Besides, LC-MS/MS-based untargeted metabolomic analysis indicated BPS impaired both bacteria and host metabolism. Additionally, transcriptome analysis of the intestine revealed abnormal gene expression in intestinal mucosal barrier and inflammation. More importantly, treating mice with antibiotics significantly attenuated BPS-induced gut inflammation via the regulation of both bacterial and host metabolites, indicating the role of gut microbiota. Collectively, BPS exposure induces intestinal inflammation via altering gut microbiota in mouse. This study provides the possibility of madecassic acid, an anti-inflammatory metabolite, to prevent BPS-induced intestinal inflammation and also new insights in understanding host-microbiota interaction in BPS toxicity.

A high-permeability method for extracting purple yam saponins based on ultrasonic-assisted natural deep eutectic solvent.

The extraction of active ingredients from traditional Chinese medicine has received considerable attentions. In this study, 16 kinds of natural deep eutectic solvent (NADES) with ultrasonic were selected to extract saponins from purple yam root and the extraction mechanism was investigated. The results showed that chloride/acrylic acid (1:2; n/n) had the highest extraction yield for saponins. The optimal extraction process parameters were 24% water content, 20 mL/g liquid-solid ratio, and ultrasonic extraction for 85 min (81 °C, 600 W). The extraction rate (ER) of purple yam saponins was 0.935%, close to the fitted result of 96.5 mg/g. Molecular dynamics simulations and FT-IR results showed that the NADES may extract the saponin constituents from purple yam through hydrogen bonding. Compared with traditional extraction methods and molecularly imprinted polymer methods, NADES has a higher ER and lower cost (1.53 $/g), which provides a reference for subsequent industrial quantitative production.

Characterization of a novel carboxylesterase from Streptomyces lividans TK24 and site-directed mutagenesis for its thermostability.

As an industrial enzyme that catalyzes the formation and cleavage of ester bonds, carboxylesterase has attracted attention in fine chemistry, pharmaceutical, biological energy and bioremediation fields. However, the weak thermostability limits their further developments in industrial applications. In this work, a novel carboxylesterase (EstF) from Streptomyces lividans TK24, belonging to family XVII, was acquired by successfully heterologous expressed and biochemically identified. The EstF exhibited optimal activity at 55 °C, pH 9.0 and excellent catalytic performances (Km = 0.263 mM, kcat/Km = 562.3 s-1 mM-1 for p-nitrophenyl acetate (pNPA2) hydrolysis). Besides, the EstF presented exceptionally high thermostability with a half-life of 387.23 h at 55 °C and 2.86 h at 100 °C. Furthermore, the EstF was modified to obtain EstFP144G using the site-directed mutation technique to investigate the effect of single glycine on thermostability. Remarkably, the mutant EstFP144G displayed a 5.10-fold increase of half-life at 100 °C versus wild-type without affecting catalytic performance. Structural analysis implied that the glycine introduction could release a steric strain and induce cooperative effects between distal residues to increase the thermostability. Therefore, the thermostable EstF and EstFP144G with prominently catalytic characteristics have potential industrial applications and the introduction of a single glycine strategy opens up alternative avenues for the thermostability engineering of other enzymes.

Two-Loop QED Corrections to the Scattering of Four Massive Leptons.

We study two-loop corrections to the scattering amplitude of four massive leptons in quantum electrodynamics. These amplitudes involve previously unknown elliptic Feynman integrals, which we compute analytically using the differential equation method. In doing so, we uncover the details of the elliptic geometry underlying this scattering amplitude and show how to exploit its properties to obtain compact, easy-to-evaluate series expansions that describe the scattering of four massive leptons in QED in the kinematical regions relevant for Bhabha and Møller scattering processes.