Highly anisotropic spin transport in ultrathin black phosphorus.

In anisotropic crystals, the direction-dependent effective mass of carriers can have a profound impact on spin transport dynamics. The puckered crystal structure of black phosphorus leads to direction-dependent charge transport and optical response, suggesting that it is an ideal system for studying anisotropic spin transport. To this end, we fabricate and characterize high-mobility encapsulated ultrathin black-phosphorus-based spin valves in a four-terminal geometry. Our measurements show that in-plane spin lifetimes are strongly gate tunable and exceed one nanosecond. Through high out-of-plane magnetic fields, we observe a fivefold enhancement in the out-of-plane spin signal case compared to in-plane and estimate a colossal spin-lifetime anisotropy of ∼6. This finding is further confirmed by oblique Hanle measurements. Additionally, we estimate an in-plane spin-lifetime anisotropy ratio of up to 1.8. Our observation of strongly anisotropic spin transport along three orthogonal axes in this pristine material could be exploited to realize directionally tunable spin transport.

Synthesis of Asp-based lactam cyclic peptides using an amide-bonded diaminodiacid to prevent aspartimide formation.

Asp-based lactam cyclic peptides are considered promising drug candidates. However, using Fmoc solid-phase peptide synthesis (Fmoc-SPPS) for these peptides also causes aspartimide formation, resulting in low yields or even failure to obtain the target peptides. Here, we developed a diaminodiacid containing an amide bond as a ß-carboxyl-protecting group for Asp to avoid aspartimide formation. The practicality of this diaminodiacid has been illustrated by the synthesis of lactam cyclic peptide cyclo[Lys9,Asp13] KIIIA7-14 and 1Y.

Prediction of postoperative complications following transanal total mesorectal excision in middle and low rectal cancer: development and internal validation of a clinical prediction model.

PURPOSE: The objective of this study is to develop a nomogram for the personalized prediction of postoperative complication risks in patients with middle and low rectal cancer who are undergoing transanal total mesorectal excision (taTME). This tool aims to assist clinicians in early identification of high-risk patients and in addressing preoperative risk factors to enhance surgical safety. METHODS: In this case-control study, 207 patients diagnosed with middle and low rectal cancer and undergoing taTME between February 2018 and November 2023 at The First Affiliated Hospital of Xiamen University were included. Independent risk factors for postoperative complications were analyzed using the Least Absolute Shrinkage and Selection Operator (LASSO) regression and multifactorial logistic regression models. A predictive nomogram was constructed using R Studio. RESULTS: Among the 207 patients, 57 (27.5%) experienced postoperative complications. The LASSO and multifactorial logistic regression analyses identified operation time (OR = 1.010, P = 0.007), smoking history (OR = 9.693, P < 0.001), anastomotic technique (OR = 0.260, P = 0.004), and ASA score (OR = 9.077, P = 0.051) as significant predictors. These factors were integrated into the nomogram. The model's accuracy was validated through receiver operating characteristic curves, calibration curves, consistency indices, and decision curve analysis. CONCLUSION: The developed nomogram, incorporating operation time, smoking history, anastomotic technique, and ASA score, effectively forecasts postoperative complication risks in taTME procedures. It is a valuable tool for clinicians to identify patients at heightened risk and initiate timely interventions, ultimately improving patient outcomes.

Synthesis and Antifungal Activity of 2-(2-Benzoxazolyl)-1-arylethanone and 2-(2-Benzoxazolyl)-1-alkylethanone Derivatives.

To discover more effective antifungal candidates, 33 benzoxazole derivatives, were designed, synthesized, and evaluated for their antifungal activity against seven phytopathogenic fungi by the mycelium growth rate method. Among 33 benzoxazole derivatives had thirteen derivatives no reported, and new derivatives C17 exhibited good inhibitory activity against Phomopsis sp. with EC50 values of 3.26 µM. Structure-activity relationship (SAR) of these derivatives analysis indicated that the substituent played a key role in antifungal activity in ortho-, meta- and para- substituted acetophenones. The preliminary mechanistic exploration demonstrated that C17 might exert its antifungal activity by targeting the mycelia cell membrane, which was verified by the observed changes in mycelial morphology, the formation of extracellular polysaccharides, cellular contents, cell membrane permeability and integrity, among other effects. Furthermore, C17 had potent curative effect against Phomopsis sp. in vivo, which indicated that C17 may be as a novelty potent antifungal agent.

Synthesis and Antifungal Activity of Curcumol Derivatives.

To discover novel and effective antifungal candidates, a series of new curcumol derivatives were designed, synthesized, and evaluated their antifungal activity against five phytopathogenic fungi by the mycelium growth rate method. Derivatives c4, c22 and c23 exhibited excellent antifungal activity against Phomopsis sp. with EC50 values of 3.06, 3.07, and 3.16 µM, respectively. Specifically, compound c4 exhibited the strongest antifungal activity against Phomopsis sp., which was 44 times that of pyrimethanil (EC50 =134.37 µM). The results of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) indicated that compound c4 could cause cell senescence and death of Phomopsis sp. by changing the normal hyphal morphology and disrupting the normal metabolism of hyphal cells. Moreover, compound c4 showed excellent curative effect against Phomopsis sp. on kiwifruit. These findings confirmed that compound c4 has great potential as a potent antifungal agent.

Quinoline Alkaloids from the Roots of Orixa japonica with the Anti-Pathogenic Fungi Activities.

A new quinoline alkaloid, 5-hydroxy-6-methoxy-N-methyl-2-phenylquinoline-4-one (1), and seventeen known quinoline alkaloids (2-18) were isolated from the roots of Orixa japonica. The structure of 1 was determined by analysis of spectroscopic data. Among them, compounds 2, 3, and 13 were isolated from this plant for the first time. All isolates were screened for the anti-pathogenic fungi activities, including Rhizoctonia solani, Magnaporthe oryzae, and Phomopsis sp. The results showed that five compounds (4, 8, 10, 11, and 12) exhibited significant anti-pathogenic fungi effects at 50.0 µg/mL. In special, compound 10 exhibited the best antifungal activities toward R. solani and M. oryzae with the IC50 values of 37.86 and 44.72 µM, respectively, better than that of the positive control, hymexazol (IC50 121.21 and 1518.18 µM, respectively). Moreover, eleven new quinoline alkaloids derivatives (12a-12k) were designed and synthesized to investigate the structure-activity relationships (SARs). The SARs analysis indicated that the furo[2,3-b]quinoline skeleton and the methoxy at C-7 (compounds 8, 11, and 12) played a key role for improving the antifungal activities.

Strong Moiré Excitons in High-Angle Twisted Transition Metal Dichalcogenide Homobilayers with Robust Commensuration.

The burgeoning field of twistronics, which concerns how changing the relative twist angles between two materials creates new optoelectronic properties, offers a novel platform for studying twist-angle dependent excitonic physics. Herein, by surveying a range of hexagonal phase transition metal dichalcogenides (TMD) twisted homobilayers, we find that 21.8 ± 1.0°-twisted (7a×7a) and 27.8 ± 1.0°-twisted (13a×13a) bilayers account for nearly 20% of the total population of twisted bilayers in solution-phase restacked bilayers and can be found also in chemical vapor deposition (CVD) samples. Examining the optical properties associated with these twisted angles, we found that 21.8 ± 1.0° twisted MoS2 bilayers exhibit an intense moiré exciton peak in the photoluminescence (PL) spectra, originating from the refolded Brillouin zones. Our work suggests that commensurately twisted TMD homobilayers with short commensurate wavelengths can have interesting optoelectronic properties that are different from the small twist angle counterparts.

Discovering the processes of undergraduate hospitality students' acceptance of facebook teaching interventions.

Technology drives innovation and reform in hospitality education, and Facebook has become a popular educational tool to facilitate students' classroom interactions. Understanding hospitality students' attitudes toward Facebook teaching interventions is important. Based on a survey of 289 undergraduate hospitality students, first, we expand the scope of the technology acceptance model (TAM) in this study, which integrates the two factors of social interaction and information exchange into the research structure. Second, this study also proposes a new moderated mediation model to account for the internal mechanism underlying Taiwanese undergraduate hospitality students' acceptance of Facebook teaching interventions in terms of perceived usefulness and ease of use. We illuminate the foundation of the application of Facebook media technology to teaching in hospitality higher education. The theoretical contributions and educational implications of this research are also discussed.

Upper Critical Solution Temperature Polyvalent Scaffolds Aggregate and Exterminate Bacteria.

Specific recognition and strong affinities of bacteria receptors with the host cell glycoconjugates pave the way to control the bacteria aggregation and kill bacteria. Herein, using aggregation-induced emission (AIE) molecules decorated upper critical solution temperature (UCST) polyvalent scaffold (PATC-GlcN), an approach toward visualizing bacteria aggregation and controlling bacteria-polyvalent scaffolds affinities under temperature stimulus is described. Polyvalent scaffolds with diblocks, one UCST block PATC of polyacrylamides showing a sharp UCST transition and typical AIE behavior, the second bacteria recognition block GlcN of hydrophilic glucosamine modified polyacrylamide, are prepared through a reversible addition and fragmentation chain transfer polymerization. Aggregated chain conformation of polyvalent scaffolds at temperature below UCST induces the aggregation of E. coli ATCC8739, because of the high density of glucosamine moieties, whereas beyond UCST, the hydrophilic state of the scaffolds dissociates the bacteria aggregation. The sweet-talking of bacteria toward the polyvalent scaffolds can be visualized by the fluorescent imaging technique, simultaneously. Due to the specific recognition of polyvalent scaffolds with bacteria, the photothermal agent IR780 loaded PATC-GlcN shows the targeted killing ability toward E. coli ATCC8739 in vitro and in vivo under NIR radiation.

Three New Pregnanes Isolated from the Cynanchum auriculatum.

Three new compounds named cynansteroid A (1), cynansteroid B (2) and cynansteroid C (3), together with nine known C21 -steroidal pregnane sapogenins (4-12) were isolated from the hydrolytic extract of the roots of Cynanchum auriculatum. The structures of cynansteroid A-C (1-3) were ascertained via the detailed analysis of the HR-ESI-MS, 1D and 2D NMR, and the calculated and experimental ECD data of cynansteroid B (2). Compound 11 displayed moderate inhibitory activity toward Verticillium dahliae Kleb (IC50 =37.15 µM), furthermore, compounds 11 and 12 showed significant inhibitory activity against Phomopsis sp. (IC50 =16.49 µM and 17.62 µM, respectively).

The regulatory mechanisms by enhancers during cancer initiation and progression.

Enhancer is a DNA sequence, and mainly acts in cis to regulate gene transcription. Due to the uncertainty in both location and distance between enhancers and their target genes, it is more complex and difficult to study the underlying regulatory mechanism of enhancers. Accumulating evidences indicate that enhancers are closely associated with the occurrence and development of diseases, such as cancer. Therefore, the studies of enhancers in cancer will be helpful to deeply unravel cancer pathogenesis and to promote the development of antitumor drugs. The related research is with great social significance and economic value. Currently, the identification of enhancers is insufficient. The regulatory mechanisms by enhancers during the initiation and progression of cancer and other diseases have not been fully delineated. In this review, we provide an overview of enhancers, super enhancers and their properties, followed by a description of enhancer prediction and identification at the genome-wide level. Finally, we summarize the regulatory roles of enhancers during diseases such as cancer in recent years, thereby providing a reference for the future exploration on enhancer regulatory mechanisms as well as cancer diagnosis and treatment.

Polycyclic polyprenylated acylphloroglucinol derivatives with neuroprotective effects from Hypericum monogynum.

A new polycyclic polyprenylated acylphloroglucinol (PPAP), hypermonin C (1), along with nine known PPAPs (2-10) were obtained from the leaves and twigs of Hypericum monogynum. The structures of the isolates were determined on the basis of extensive spectroscopic analysis. The neuroprotective effects of the isolates against several chemical-induced injuries in SH-SY5Y and PC12 cells were assessed, and most of the compounds exhibited significant protective effects at 10 µg/ml. Especially, three compounds (1, 3, and 7) showed excellent neuroprotective activity with a cell viability of 92.4% ∼ 95.8% in KCl-induced SH-SY5Y cell injury. Their preliminary structure-activity relationship was also discussed and the configuration of substituent in furohyperforin may be critical for the neuroprotective activity of PPAP derivatives.

MTHFR Knockdown Assists Cell Defense against Folate Depletion Induced Chromosome Segregation and Uracil Misincorporation in DNA.

Folate depletion causes chromosomal instability by increasing DNA strand breakage, uracil misincorporation, and defective repair. Folate mediated one-carbon metabolism has been suggested to play a key role in the carcinogenesis and progression of hepatocellular carcinoma (HCC) through influencing DNA integrity. Methylenetetrahydrofolate reductase (MTHFR) is the enzyme catalyzing the irreversible conversion of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate that can control folate cofactor distributions and modulate the partitioning of intracellular one-carbon moieties. The association between MTHFR polymorphisms and HCC risk is inconsistent and remains controversial in populational studies. We aimed to establish an in vitro cell model of liver origin to elucidate the interactions between MTHFR function, folate status, and chromosome stability. In the present study, we (1) examined MTHFR expression in HCC patients; (2) established cell models of liver origin with stabilized inhibition of MTHFR using small hairpin RNA delivered by a lentiviral vector, and (3) investigated the impacts of reduced MTHFR and folate status on cell cycle, methyl group homeostasis, nucleotide biosynthesis, and DNA stability, all of which are pathways involved in DNA integrity and repair and are critical in human tumorigenesis. By analyzing the TCGA/GTEx datasets available within GEPIA2, we discovered that HCC cancer patients with higher MTHFR had a worse survival rate. The shRNA of MTHFR (shMTHFR) resulted in decreased MTHFR gene expression, MTHFR protein, and enzymatic activity in human hepatoma cell HepG2. shMTHFR tended to decrease intracellular S-adenosylmethionine (SAM) contents but folate depletion similarly decreased SAM in wildtype (WT), negative control (Neg), and shMTHFR cells, indicating that in cells of liver origin, shMTHFR does not exacerbate the methyl group supply in folate depletion. shMTHFR caused cell accumulations in the G2/M, and cell population in the G2/M was inversely correlated with MTHFR gene level (r = -0.81, p < 0.0001), MTHFR protein expression (r = -0.8; p = 0.01), and MTHFR enzyme activity (r = -0.842; p = 0.005). Folate depletion resulted in G2/M cell cycle arrest in WT and Neg but not in shMTHFR cells, indicating that shMTHFR does not exacerbate folate depletion-induced G2/M cell cycle arrest. In addition, shMTHFR promoted the expression and translocation of nuclei thymidine synthetic enzyme complex SHMT1/DHFR/TYMS and assisted folate-dependent de novo nucleotide biosynthesis under folate restriction. Finally, shMTHFR promoted nuclear MLH1/p53 expression under folate deficiency and further reduced micronuclei formation and DNA uracil misincorporation under folate deficiency. In conclusion, shMTHFR in HepG2 induces cell cycle arrest in G2/M that may promote nucleotide supply and assist cell defense against folate depletion-induced chromosome segregation and uracil misincorporation in the DNA. This study provided insight into the significant impact of MTHFR function on chromosome stability of hepatic tissues. Data from the present study may shed light on the potential regulatory mechanism by which MTHFR modulates the risk for hepatic malignancies.

Simultaneous determination of primary particle size distribution and thermal accommodation coefficient of soot aggregates using low-fluence LII.

For the ill-posed inverse problem of LII-based nanoparticle size measurement, recovered primary particle size distribution (PPSD) is sensitive to the uncertainty of LII model parameters. In the absence of reliable prior knowledge, the thermal accommodation coefficient (TAC) and fractal-dependent shielding factor are often required to be inferred simultaneously with the PPSD. In the simplified LII model for low fluence regime, TAC and fractal-dependent shielding factor are combined to define a new fractal-dependent TAC. The present study theoretically verified the feasibility of inferring PPSD and fractal-dependent TAC from the normalized LII signals. Moreover, the inversion is independent of prior knowledge of most full LII model parameters, which is attributed to low laser fluence, normalized signal, and fractal-dependent TAC.

Chronic Inflammatory and Proliferative Lesions of the Gallbladder in Aged Pigs.

Primary epithelial tumors of the gallbladder are rarely reported in animals. In this study, 9 aged pigs (6-12 years old) were histopathologically examined for gallbladder proliferative lesions. At necropsy, a large gallstone occupied the lumen of the gallbladder of 3 pigs. Histopathological examination revealed chronic cholecystitis in all 9 pigs, mucosal hyperplasia in 2 pigs, adenoma in 1 pig, and adenocarcinoma in 2 pigs. Bacilli were detected in the gallbladder lumen of 6 pigs by Warthin-Starry stain. Mucosal hyperplasia, adenoma, and adenocarcinoma were characterized by papillary projections of the mucosa with occasional acinar structures. Tumor invasion of the surrounding tissue was observed in the cases of adenocarcinoma. On Alcian blue and periodic acid-Schiff double-stained sections, the acinar structure of gallbladder mucosa in chronic cholecystitis and mucosal hyperplasia was stained in a mosaic pattern, indicating pyloric gland metaplasia. The results of immunohistochemistry revealed a CD10-positive epithelial brush border and mucin (MUC) 2-positive goblet cells in chronic cholecystitis, adenoma, and adenocarcinomas, indicating intestinal metaplasia. Immunoreactivity of MUC5 AC and cytokeratin 19 was weaker in adenoma and adenocarcinomas compared with the normal and hyperplastic gallbladder mucosa. The number of p53-positive nuclei and the Ki-67 index were higher in adenocarcinomas compared with benign lesions. These results suggest that chronic cholecystitis associated with gallstones and/or bacterial infections may contribute to metaplastic changes and development of gallbladder tumors in aged pigs. Alteration of mucin, cytokeratin, and p53 profiles in gallbladder proliferative lesions in pigs were similar to that in humans, suggesting a common pathogenesis in tumor development.

Design, synthesis, and cytotoxic activities of novel hybrids of parthenolide and thiazolidinedione via click chemistry.

A series of novel parthenolide-thiazolidinedione hybrids have been synthesized via a click chemistry-mediated coupling between parthenolide and thiazolidinedione, and evaluated for their cytotoxic activities. The results indicated that all the hybrids showed moderate cytotoxic effects on human cancer cell lines, including human erythroleukemia cell line (HEL), prostate (PC3), and breast (MDA-MB-231) by MTT assay. In particular, compound VI-6 exhibited the best cytotoxic activities against the MDA-MB-231 cells with IC50 value of 2.07 µM, which was about eight times more active than that of the original compound (PTL). These interesting results might be used to develop novel lead scaffolds for potential anticancer agents.

Retrieval of fractal dimension and size distribution of non-compact soot aggregates from relative intensities of multi-wavelength angular-resolved light scattering.

A new technique is developed to retrieve the fractal dimension and size distribution of soot aggregates simultaneously from the relative intensities of multi-wavelength angular-resolved light scattering. Compared with other techniques, the main advantage of this method is its independence of knowing complex refractive index, number density of aggregate, fractal prefactor and primary particle diameter. The forward light scattering procedure of soot aggregate is described by Rayleigh-Debye-Gans polydisperse fractal aggregate (RDG-PFA) scattering theory, and the retrieval process is performed by using the covariance matrix adaption-evolution strategy algorithm (CMA-ES). Three different measurement models, i.e. absolute scattering and transmittance, absolute scattering, relative scattering (RS), are investigated in present research. Numerical experiments have been performed to test the feasibility of the CMA-ES algorithm. Combined with the multi-wavelength RDG-PFA strategy, the retrieval accuracy of soot aggregate size distribution is proved to be more effectively by using the RS model. Satisfactory results under 10% Gaussian measurement noise have demonstrated the feasibility of the proposed method.

Reduction of N2O by H2 Catalyzed by Keggin-Type Phosphotungstic Acid Supported Single-Atom Catalysts: An Insight from Density Functional Theory Calculations.

In the present paper, the mechanisms of N2O reduction by H2 were systemically examined over various polyoxometalate-supported single-atom catalysts (SACs) M1/PTA (M = Fe, Co, Mn, Ru, Rh, Os, Ir, and Pt; PTA = [PW12O40]3-) by means of density functional theory calculations. Among these M1/PTA SACs, Os1/PTA SAC possesses high activity for N2O reduction by H2 with a relatively low rate-determining barrier. The favorable catalytic pathway involves the first and second N2O decomposition over the Os1/PTA SAC and hydrogenation of the key species after the second N2O decomposition. Molecular geometry and electronic structure analyses along the favorable reaction pathway indicate that a strong charge-transfer cooperative effect of metal and support effectively improves the catalytic activity of Os1/PTA SAC. The isolated Os atom not only plays the role of adsorption and activation of the N2O molecule but also works as an electron transfer medium in the whole reaction process. Meanwhile, the PTA support with very high redox stability has also been proven to be capable of transporting the electron to promote the whole reaction. We expect that our computation results can provide ideas for designing new SACs for N2O reduction by using H2 selective catalytic reduction technology.

[C_(19)-diterpenoid alkaloids from Aconitum austroyunnanense].

Eight C_(19)-diterpenoid alkaloids( 1-8) were isolated from the ethyl acetate soluble fraction of 95% ethanol extract of the ground roots of Aconitum austroyunnanense through various column chromatographies on silica gel,ODS,Sephadex LH-20 and MCI gel.Their structures were elucidated as 14α-benzoyloxy-13ß,15α-dihydroxy-1α,6α,8ß,16ß,18-pentamethoxy-19-oxoaconitan( 1),N-deethylaconitine( 2),spicatine B( 3),leucanthumsine A( 4),acofamine B( 5),macrorhynine B( 6),aconitilearine( 7),and ambiguine( 8) based on their chemical and physicochemical properties and spectroscopic data. Compound 1 was a new compound and alkaloids 2-8 were isolated from this plant for the first time. Some isolated alkaloids were tested in vitro for cytotoxic potential by employing the MTT method. As a result,alkaloid 1 exhibited weak cytotoxic activity against three tested tumor cell lines( A-549,He La,and Hep G2) with IC_(50) values less than 20 µmol·L~(-1).

Helicase POLQ-like (HELQ) as a novel indicator of platinum-based chemoresistance for epithelial ovarian cancer.

OBJECTIVE: To investigate the role of HELQ in chemo-resistance of epithelial ovarian carcinoma (EOC), which is a critical factor of patients' prognosis. METHODS: Immunohistochemistry, survival analysis of our 87 EOC patients and bioinformatics analysis of The Cancer Genome Atlas (TCGA) datasets (Nature, 2011) disclosed the clinical importance of HELQ expression. Quantitative reverse transcription polymerase chain reaction (qRT-PCR), and Western Blot analyses of EOC tissue were used to confirm it. Ectopic overexpression and RNA interference knockdown of HELQ were carried out in OVCAR3 and A2780 cell lines, respectively, to determine the effect of altered HELQ expression on cellular response to cisplatin by CCK8 assay. The DNA repair capacity of these cells was evaluated by using host-cell reactivation assay. Western Blot analyses were carried out to determine the effect of HLEQ on the DNA repair genes by using cells with altered HELQ expression. RESULTS: HELQ expression associates with response of EOC patients to platinum-based chemotherapy and their overall survival (OS), disease free survival (DFS). HELQ overexpression or knockdown, respectively, increased and decreased the cellular resistance to cisplatin, DNA repair activity, and expression of DNA repair proteins of Nucleotide excision repair (NER) pathway. CONCLUSIONS: HELQ plays an important role in regulating the expression of DNA repair proteins NER pathway which, in turn, contributes to cellular response to cisplatin and patients' response to platinum-based chemotherapy. Our results demonstrated that HELQ could serve as a novel indicator for chemo-resistance of EOC, which can predict the prognosis of the disease.