Ag-Catalyzed Selective C-C Bond Activation of Cyclopropenones to Access α-Alkylidene Lactones.

A novel Ag-catalyzed ring opening of unsymmetric cyclopropenones for the stereoselective synthesis of a diverse range of α-alkylidene lactones has been developed. In this protocol, two different C-C(O) bonds were distinguished, demonstrating selective C-C bond activation. This reaction features a wide substrate scope, good functional group compatibility, and high atom economy, providing a versatile and general approach to the construction of α-alkylidene lactones.

Accurate diagnosis of severe coronary stenosis based on resting magnetocardiography: a prospective, single-center, cross-sectional analysis.

OBJECTIVE: To evaluate the role of resting magnetocardiography in identifying severe coronary artery stenosis in patients with suspected coronary artery disease. METHODS: A total of 513 patients with angina symptoms were included and divided into two groups based on the extent of coronary artery disease determined by angiography: the non-severe coronary stenosis group (< 70% stenosis) and the severe coronary stenosis group (≥ 70% stenosis). The diagnostic model was constructed using magnetic field map (MFM) parameters, either individually or in combination with clinical indicators. The performance of the models was evaluated using receiver operating characteristic curves, accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). Calibration plots and decision curve analysis were performed to investigate the clinical utility and performance of the models, respectively. RESULTS: In the severe coronary stenosis group, QR_MCTDd, S_MDp, and TT_MAC50 were significantly higher than those in the non-severe coronary stenosis group (10.46 ± 10.66 vs. 5.11 ± 6.07, P < 0.001; 7.2 ± 8.64 vs. 4.68 ± 6.95, P = 0.003; 0.32 ± 57.29 vs. 0.26 ± 57.29, P < 0.001). While, QR_MVamp, R_MA, and T_MA in the severe coronary stenosis group were lower (0.23 ± 0.16 vs. 0.28 ± 0.16, P < 0.001; 55.06 ± 48.68 vs. 59.24 ± 53.01, P < 0.001; 51.67 ± 39.32 vs. 60.45 ± 51.33, P < 0.001). Seven MFM parameters were integrated into the model, resulting in an area under the curve of 0.810 (95% CI: 0.765-0.855). The sensitivity, specificity, PPV, NPV, and accuracy were 71.7%, 80.4%, 93.3%, 42.8%, and 73.5%; respectively. The combined model exhibited an area under the curve of 0.845 (95% CI: 0.798-0.892). The sensitivity, specificity, PPV, NPV, and accuracy were 84.3%, 73.8%, 92.6%, 54.6%, and 82.1%; respectively. Calibration curves demonstrated excellent agreement between the nomogram prediction and actual observation. The decision curve analysis showed that the combined model provided greater net benefit compared to the magnetocardiography model. CONCLUSIONS: The novel quantitative MFM parameters, whether used individually or in combination with clinical indicators, have been shown to effectively predict the risk of severe coronary stenosis in patients presenting with angina-like symptoms. Magnetocardiography, an emerging non-invasive diagnostic tool, warrants further exploration for its potential in diagnosing coronary heart disease.

Pd-Catalyzed Three-Component Coupling of Cyclopropenones via Sequential C-C Bond Activation and Allylation.

A novel Pd-catalyzed three-component domino reaction for the stereoselective synthesis of highly functionalized allyl cinnamates has been developed. In this protocol, a sequential process of C-C bond activation and intermolecular allylic substitution was well-organized. The key for this transformation is the in situ generated hydrolysis product of cyclopropenone, which triggered a new reaction with vinylethylene carbonates. The reaction mechanism was investigated, demonstrating the high stereoselectivity and excellent atomic economy in this process.

Effects of microcystin on protein profile in hepatopancreas of Litopenaeus vannamei.

For intensive aquaculture in freshwater ponds, microcystin (MC-LR) generated from cyanobacterial blooms is one of the bottlenecks for the healthy and sustainable development of shrimp aquaculture industry. In this study, we measured the MC-LR content in the hepatopancreas and muscles of Litopenaeus vannamei stressed by MC-LR, and analyzed protein expression in the hepatopancreas using DIA high-throughput proteomics technology. The results showed that MC-LR content in the hepatopancreas and muscles reached the highest at 1 h after MC-LR injection, which was (6.12±0.45) µg·kg-1 and (5.00±0.19) µg·kg-1, respectively. Then, it decreased gra-dually, with that in the hepatopancreas being significantly higher than in muscles. We identified 820 differential expressed proteins, including 586 up-regulated and 234 down-regulated ones. Results of bioinformatics analysis showed that MC-LR stress significantly affected immune-related pathways such as lysosome, RIG-Ⅰ receptor signals and interleukin-2. It also altered energy metabolisms including citrate cycle, metabolism of starch and sucrose, and interconversion of pentose and glucoronate, which in turn led to the disorder of carbohydrate metabolism. In addition, MC-LR significantly upregulated 19 cytoskeleton-related blood shadow proteins and damaged the hepatopancreas cytoskeleton. It was concluded that MC-LR mainly affected the physiological processes associated with immunity, energy metabolism, and cytoskeleton in the hepatopancreas of L. vannamei.

Identification of plasma SAA2 as a candidate biomarker for the detection and surveillance of non-small cell lung cancer.

This study aimed to measure the expression of SAA2 in plasma and to assess its diagnostic efficacy as a biomarker for non-small cell lung cancer (NSCLC). The gene expression of SAA2 in NSCLC was analyzed based on a database. Then, SAA2 expression was detected by immunohistochemistry in lung tissue and by enzyme-linked immunosorbent assay in 90 patients with NSCLC and 61 normal controls. Finally, the diagnostic performance was assessed in terms of accuracy, sensitivity, and specificity. At the gene and protein levels, the SAA2 expression was significantly higher in the NSCLC group than in the control group (p<0.01). It was higher in lung squamous carcinoma than in lung adenocarcinoma and in males than in females, and this trend was also observed in the lung squamous carcinoma group. Of note, the expression of SAA2 increased with increasing disease stage. Receiver operating characteristic (ROC) curve analysis revealed that the sensitivity of SAA2 was 83.61%, the specificity was 91.11%, and the area under the curve (AUC) was 0.9252. Its accuracy was 68.89%, which was higher than that of other conventional diagnostic biomarkers, and the combined application can effectively improve the diagnostic efficiency. Based on the results, SAA2 expression was positively correlated with the disease stage of NSCLC. Notably, SAA2 is more concerning in male patients with lung squamous carcinoma, and it can help in the screening and diagnosis of NSCLC. SAA2 may represent a novel diagnostic biomarker in NSCLC.

A Rapid and Accurate Detection Approach for Multidrug-Resistant Tuberculosis Based on PCR-ELISA Microplate Hybridization Assay.

Rapid and accurate diagnosis of multidrug-resistant tuberculosis (MDR-TB) is important for timely and appropriate therapy. In this study, a rapid and easy-to-perform molecular test that integrated polymerase chain reaction (PCR) amplification and a specific 96-well microplate hybridization assay, called PCR-ELISA (enzyme-linked immunosorbent assay), were developed for detection of mutations in rpoB, katG, and inhA genes responsible for rifampin (RIF) and isoniazid (INH) resistance and prediction of drug susceptibility in Mycobacterium tuberculosis clinical isolates. We evaluated the utility of this method by using 32 multidrug-resistent (MDR) isolates and 22 susceptible isolates; subsequently, we compared the results with data obtained by conventional drug susceptibility testing and DNA sequencing. The sensitivity and specificity of the PCR-ELISA test were 93.7% and 100% for detecting RIF resistance, and 87.5% and 100% for detecting INH resistance, respectively. These results were comparable to those yielded by commercially available molecular tests such as the GenoType MTBDRplus assay. Based on the aforementioned results, we conclude that the PCR-ELISA microplate hybridization assay is a rapid, inexpensive, convenient, and reliable test that will be useful for rapid diagnosis of MDR-TB, for improved clinical care.

Solution and rheological properties of cationic cellulose/gemini surfactant: Effect of the alkyl chain and spacer length.

In this paper, three sulfonate-containing gemini surfactants, sodium 1,1'-(4,4'-methylenebis(4,1-phenylene))bis(1-oxooctane-2-sulfonate) (C8-M1-C8), sodium 1,1'-(4,4'-(ethane-1,2-diyl)bis(4,1-phenylene))bis(1-oxooctane-2-sulfonate) (C8-M2-C8), sodium 1,1'-(4,4'-methylenebis(4,1-phenylene))-bis(1-oxododecane-2-sulfonate) (C12-M2-C12), were synthesized and characterized with FT-IR, 1H NMR and MS. Furthermore, interaction between a cationic cellulose-based polyelectrolyte, PQ-10, and gemini surfactants were investigated by surface tension, turbidity, flow and low-amplitude oscillation rheology analysis. For comparing, the interaction of their corresponding monomeric counterpart sodium dodecyl sulfate (SDS), sodium 1-octanesulfate (SOS) was also studied. Results showed that the concentration value at T1, defined as critical surface complex concentration, for the PQ-10/surfactant was in order of PQ-10/C8-M2-C8> PQ-10/C8-M1-C8 > PQ-10/C12-M2-C12. Precipitation appeared at low concentration for Gemini surfactants than their monomeric counterparts, and for the gemini surfactants with shorter spacer or longer hydrocarbon chain. The increase/decrease of the crossover frequency (ωc) (the relaxation time, τc) for PQ-10/C12-M2-C12 indicated the formation/collapse of network structures, while PQ-10/SDS showed no obvious change.

Pharmacologic ascorbate as a pro-drug for hydrogen peroxide release to kill mycobacteria.

BACKGROUND AND PURPOSE: Tuberculosis is one of the most highly fatal diseases worldwide, and one-third of the world's population has been infected with Mycobacterium tuberculosis (M. tuberculosis). A previous study showed that M. tuberculosis was highly susceptible to being killed by ascorbate (i.e. vitamin C, VC), but the molecular mechanisms of the bactericidal activity of VC against M. tuberculosis are still not well understood. EXPERIMENTAL APPROACH: We assayed the effects of VC as an anti-tuberculosis drug against mycobacteria (i.e. M. bovis BCG or M. tuberculosis H37Rv) in macrophages (i.e. RAW 264.7 cells). Relative global protein expression changes in 5 mM VC-treated and control samples of H37Rv were investigated by Tandem mass tag (TMT)-based quantitative proteomic analysis. qRT-PCR was also used to measure the differential expression of six intracellular stress response mycobacteria genes. KEY RESULTS: Quantitative proteomic analysis showed that 11 peptide components including rip3, fdxA, Rv2028c, mtp, LH57_00670, hspX, pfkB, Rv1824, Rv1813c, LH57_08410 and Rv2030c were up-regulated and 17 peptide components were down-regulated in 5 mM VC-treated H37Rv compared with the control samples. qRT-PCR also verified that VC could induce the expression of six genes (hsp, fdxD, furA, devR, hspX, and dnaB) in BCG and H37Rv. We also found that exosomes from RAW 264.7 cells treated with pharmacologic VC could kill M. bovis BCG in vitro. CONCLUSION AND IMPLICATIONS: Our results demonstrated that the bactericidal activity of VC against mycobacteria, as a pro-drug for hydrogen peroxide formation (H2O2), was dependent on reactive oxygen species production and the activated oxidative stress pathway, which suggested that pharmaceutical VC and exosomes from macrophages treated with VC could be used as potential anti-tuberculosis drugs.

Direct generation of vortex beams from a double-end polarized pumped Yb:KYW laser.

Double-end polarized pumping scheme combined with off-axis pumping technique has been first introduced to generate vortex beams in a z-type cavity. By employing double-end pumping, two different transverse modes can be excited simultaneously. The phase delay between these two modes can be finely tuned by manipulating the cavity structure. Direct emission of a chirality controllable Laguerre Gaussian LG01 vortex beam with slope efficiency of more than 40% has been realized by a double-end polarized pumped Yb:KYW laser. Other modes, such as dual-LG01 mode, cross-shaped mode, and LG10 mode, have also been demonstrated from our laser setup.

[Chemical constitutes from Clerodendrum japonicum].

The chemical constituents from the ethanol extract of Clerodendrum japonicum were isolated by a combination of various chromatographic techniques including column chromatography over silica gel, sephadex LH-20, ODS and reversed phase HPLC. Sixteen compounds with a pair of epimers were elucidated through the application of physicochemical properties with modern spectral analysis technology as 7α-hydroxy syringaresinol (1), (-)-syringaresinol (2), (-)-medioresinol (3), 2″,3″-O-acetylmartyonside (4), 2″-O-acetyl-martyonside (5), martinoside (6), monoacetyl martinoside (7)，cytochalasin O (8), 9-epi-blumenol B (9), (6R, 9S) and (6R,9R)-9-hydroxy-4-megastigmen-3-one (10a，10b), (6R,9S)-3-oxo-α-ionol (11), (-)-dehydrovomifoliol (12)，megastigm-5-en-3,9-diol (13), (3R,6E,10S)-2,6,10-trimethyl-3-hydroxydodeca-6,11-diene-2,10-diol (14), (2R)-butylitaconic acid (15), 3-(3&-hydroxybutyl)-2,4,4-trimethylcyclohexa-2,5-dienone (16), (-)-loliolide (17), of which compound 1 and 15 are new natural product, the other compounds were isolated for the first time from Clerodendrum japonicum except for compounds 4, 6 and 7.