1,156 research outputs found

    Charm-strange baryon strong decays in a chiral quark model

    Full text link
    The strong decays of charm-strange baryons up to N=2 shell are studied in a chiral quark model. The theoretical predictions for the well determined charm-strange baryons, Ξc(2645)\Xi_c^*(2645), Ξc(2790)\Xi_c(2790) and Ξc(2815)\Xi_c(2815), are in good agreement with the experimental data. This model is also extended to analyze the strong decays of the other newly observed charm-strange baryons Ξc(2930)\Xi_c(2930), Ξc(2980)\Xi_c(2980), Ξc(3055)\Xi_c(3055), Ξc(3080)\Xi_c(3080) and Ξc(3123)\Xi_c(3123). Our predictions are given as follows. (i) Ξc(2930)\Xi_c(2930) might be the first PP-wave excitation of Ξc\Xi_c' with JP=1/2J^P=1/2^-, favors the $|\Xi_c'\ ^2P_\lambda 1/2^->or or |\Xi_c'\ ^4P_\lambda 1/2^->state.(ii) state. (ii) \Xi_c(2980)mightcorrespondtotwooverlapping might correspond to two overlapping Pwavestates-wave states |\Xi_c'\ ^2P_\rho 1/2^->and and |\Xi_c'\ ^2P_\rho 3/2^->,respectively.The, respectively. The \Xi_c(2980)observedinthe observed in the \Lambda_c^+\bar{K}\pifinalstateismostlikelytobethe final state is most likely to be the |\Xi_c'\ ^2P_\rho 1/2^->state,whilethenarrowerresonancewithamass state, while the narrower resonance with a mass m\simeq 2.97GeVobservedinthe GeV observed in the \Xi_c^*(2645)\pichannelfavorstobeassignedtothe channel favors to be assigned to the |\Xi_c'\ ^2P_\rho 3/2^->state.(iii) state. (iii) \Xi_c(3080)favorstobeclassifiedasthe favors to be classified as the |\Xi_c\ S_{\rho\rho} 1/2^+>state,i.e.,thefirstradialexcitation(2S)of state, i.e., the first radial excitation (2S) of \Xi_c.(iv). (iv) \Xi_c(3055)ismostlikelytobethefirst is most likely to be the first Dwaveexcitationof-wave excitation of \Xi_cwith with J^P=3/2^+,favorsthe, favors the |\Xi_c\ ^2D_{\lambda\lambda} 3/2^+>state.(v) state. (v) \Xi_c(3123)mightbeassignedtothe might be assigned to the |\Xi_c'\ ^4D_{\lambda\lambda} 3/2^+>,, |\Xi_c'\ ^4D_{\lambda\lambda} 5/2^+>,or, or |\Xi_c\ ^2D_{\rho\rho} 5/2^+>state.Asabyproduct,wecalculatethestrongdecaysofthebottombaryons state. As a by-product, we calculate the strong decays of the bottom baryons \Sigma_b^{\pm},, \Sigma_b^{*\pm}and and \Xi_b^*$, which are in good agreement with the recent observations as well.Comment: 15 pages, 9 figure

    Further understanding the nature of Ω(2012)\Omega(2012) within a chiral quark model

    Full text link
    In our previous works, we have analyzed the two-body strong decays of the low-lying Ω\Omega baryon states within a chiral quark model. The results show that the Ω(2012)\Omega(2012) resonance favors the three-quark state with JP=3/2J^P=3/2^- classified in the quark model. With this assignment, in the present work we further study the three-body strong decay Ω(2012)Ξ(1530)KˉΞπKˉ\Omega(2012)\to \Xi^*(1530)\bar{K} \to \Xi\pi\bar{K} and coupled-channel effects on Ω(2012)\Omega(2012) from nearby channels ΞKˉ\Xi \bar{K}, Ωη\Omega\eta and Ξ(1530)Kˉ\Xi^*(1530)\bar{K} within the chiral quark model as well. It is found that the Ω(2012)\Omega(2012) resonance has a sizeable decay rate into the three-body final state ΞπKˉ\Xi\pi\bar{K}. The predicted ratio RΞKˉΞπKˉ=B[Ω(2012)Ξ(1530)KˉΞπKˉ]/B[Ω(2012)ΞKˉ]12%R_{\Xi\bar{K}}^{\Xi\pi\bar{K}}=\mathcal{B}[\Omega(2012)\to \Xi^*(1530)\bar{K}\to \Xi\pi\bar{K}]/\mathcal{B}[\Omega(2012)\to \Xi\bar{K}]\simeq 12\% is close to the up limit 11%11\% measured by the Belle Collaboration in 2019, however, our predicted ratio is too small to be comparable with the recent data 0.97±0.310.97\pm 0.31. Furthermore, our results show that the coupled-channel effects on the Ω(2012)\Omega(2012) is not large, its components should be dominated by the bare three-quark state, while the proportion of the molecular components is only 16%\sim 16\%. To clarify the nature of Ω(2012)\Omega(2012), the ratio RΞKˉΞπKˉR_{\Xi\bar{K}}^{\Xi\pi\bar{K}} is expected to be tested by other experiments.Comment: 7 pages, 3 figure

    Effect of Thiazolidinedione Amide on Insulin Resistance, Creactive Protein and Endothelial Function in Young Women with Polycystic Ovary Syndrome

    Get PDF
    Purpose: To investigate the effect of thiazolidinedione amide (TZDA) treatment on high-sensitivity Creactive protein (hsCRP) levels and endothelial dysfunction in patients with polycystic ovary syndrome (PCOS).Methods: Twenty five women (mean age 24.7 ± 3.9 years; mean body mass index (BMI), 23.2 ± 4.0 kg/m2) with PCOS were treated with 15 μM TZDA daily for 12 months. Serum levels of testosterone, leutenizing hormone (LH), follicle stimulating hormone (FSH), sex hormone-binding globulin (SHBG), insulin and hsCRP were measured. BMI, hirsutism scores and insulin sensitivity indices were also calculated prior to and after TZDA treatment. Brachial artery responses to stimuli was used to measure arterial endothelium and smooth muscle function prior to and after the treatment.Results: TZDA treatment caused a significant (p < 0.05) decrease in serum testosterone from 93.1 ± 40.3 to 54.8 ± 19.5 ng/dl and fasting insulin concentration from 11.9 ± 6.8 to 9.23 ± 5.13 U/mL. Insulin resistance index significantly (p < 0.05) improved and hirsutism score decreased significantly from 11.6 ± 2.0 to 6.8 ± 2.0. BMI, waist circumference, serum total cholesterol, low-density lipoprotein (LDL)- cholesterol, FSH and LH levels remained almost unchanged. Twenty-four of the women reverted to regular menstrual cycles. SHBG levels showed a significant (p < 0.05) increase from 24.8 ± 9.5 to 49.1 ± 13.5 nmol/L after TZDA treatment. Serum hsCRP levels decreased (p < 0.05) from 0.25 ± 0.1 to 0.09 ± 0.02 mg/dL while endothelium-dependent vascular responses significantly improved (p < 0.05) following TZDA treatment (9.9 ± 3.9 vs 16.4 ± 5.1%).Conclusion: TZDA treatment improves insulin sensitivity, decreases androgen production and improves endothelial dysfunction in young women with PCOS.Keywords: Thiazolidinedione amide, Insulin sensitivity, Endothelial dysfunction, Polycystic ovary syndrom

    Toksičnost aromatskih ketona za stanice kvasca i ubrzanje njihove redukcije primjenom adsorpcijskih smola

    Get PDF
    Asymmetric reduction of the prochiral aromatic ketone catalyzed by yeast cells is one of the most promising routes to produce its corresponding enantiopure aromatic alcohol, but the space-time yield does not meet people’s expectations. Therefore, the toxicity of aromatic ketone and aromatic alcohol to the yeast cell is investigated in this work. It has been found that the aromatic compounds are poisonous to the yeast cell. The activity of yeast cell decreases steeply when the concentration of acetophenone (ACP) is higher than 30.0 mmol/L. Asymmetric reduction of acetophenone to chiral S-α-phenylethyl alcohol (PEA) catalyzed by the yeast cell was chosen as the model reaction to study in detail the promotion effect of the introduction of the resin adsorption on the asymmetric reduction reaction. The resin acts as the substrate reservoir and product extraction agent in situ. It has been shown that this reaction could be remarkably improved with this technique when the appropriate kind of resin is applied. The enantioselectivity and yield are acceptable even though the initial ACP concentration reaches 72.2 mmol/L.Asimetrična redukcija prokiralnih aromatskih ketona, katalizirana stanicama kvasca, obećavajuća je metoda proizvodnje enantiomerno čistih aromatskih alkohola, no iskorištenje reakcije ne zadovoljava današnje potrebe. U radu je utvrđena toksičnost aromatskih ketona i alkohola za stanice kvasca. Aktivnost stanica kvasca naglo se smanjila pri koncentracijama acetofenona većim od 30 mmol/L. Kao model reakcije za detaljno ispitivanje pozitivnog učinka uvođenja adsorpcijskih smola odabrana je asimetrična redukcija acetofenona u kiralni S-α-feniletilni alkohol, katalizirana stanicama kvasca. Utvrđeno je da smola djeluje kao rezervoar supstrata i agens za ekstrakciju proizvoda in situ. Tako se odvijanje reakcije može znatno poboljšati uvođenjem prikladne smole. Enantioselektivnost i prinos su zadovoljavajući iako je početna koncentracija acetofenona dosegla čak 72,2 mmol/L

    Improving the Accuracy of Density Functional Theory (DFT) Calculation for Homolysis Bond Dissociation Energies of Y-NO Bond: Generalized Regression Neural Network Based on Grey Relational Analysis and Principal Component Analysis

    Get PDF
    We propose a generalized regression neural network (GRNN) approach based on grey relational analysis (GRA) and principal component analysis (PCA) (GP-GRNN) to improve the accuracy of density functional theory (DFT) calculation for homolysis bond dissociation energies (BDE) of Y-NO bond. As a demonstration, this combined quantum chemistry calculation with the GP-GRNN approach has been applied to evaluate the homolysis BDE of 92 Y-NO organic molecules. The results show that the ull-descriptor GRNN without GRA and PCA (F-GRNN) and with GRA (G-GRNN) approaches reduce the root-mean-square (RMS) of the calculated homolysis BDE of 92 organic molecules from 5.31 to 0.49 and 0.39 kcal mol−1 for the B3LYP/6-31G (d) calculation. Then the newly developed GP-GRNN approach further reduces the RMS to 0.31 kcal mol−1. Thus, the GP-GRNN correction on top of B3LYP/6-31G (d) can improve the accuracy of calculating the homolysis BDE in quantum chemistry and can predict homolysis BDE which cannot be obtained experimentally

    Safety and efficacy of etomidate and propofol anesthesia in elderly patients undergoing gastroscopy: A double-blind randomized clinical study

    Get PDF
    The aim of the present study is to compare the safety, efficacy and cost effectiveness of anesthetic regimens by compound, using etomidate and propofol in elderly patients undergoing gastroscopy. A total of 200 volunteers (65–79 years of age) scheduled for gastroscopy under anesthesia were randomly divided into the following groups: P, propofol (1.5–2.0 mg/kg); E, etomidate (0.15-0.2 mg/kg); P+E, propofol (0.75–1 mg/kg) followed by etomidate (0.075-0.1 mg/kg); and E+P, etomidate (0.075-0.01 mg/kg) followed by propofol (0.75–1 mg/kg). Vital signs and bispectral index were monitored at different time points. Complications, induction and examination time, anesthesia duration, and recovery and discharge time were recorded. At the end of the procedure, the satisfaction of patients, endoscopists and the anesthetist were evaluated. The recovery (6.1±1.2 h) and discharge times (24.8±2.8 h) in group E were significantly longer compared with groups P, P+E and E+P (P<0.05). The occurrence of injection pain in group P+E was significantly higher compared with the other three groups (P<0.05). In addition, the incidence of myoclonus and post-operative nausea and vomiting were significantly higher in group P+E compared with the other three groups (P<0.05). There was no statistical difference among the four groups with regards to the patients' immediate, post-procedure satisfaction (P>0.05). Furthermore, there was no difference in the satisfaction of anesthesia, as evaluated by the anesthetist and endoscopist, among the four groups (P>0.05). The present study demonstrates that anesthesia for gastroscopy in elderly patients can be safely and effectively accomplished using a drug regimen that combines propofol with etomidate. The combined use of propofol and etomidate has unique characteristics which improve hemodynamic stability, cause minimal respiratory depression and less side effects, provide rapid return to full activity and result in high levels of satisfaction

    Primary studies of Chinese spaceborne SAR

    Get PDF
    The primary studies on spaceborne synthetic aperture radar (SAR) in China are discussed. The SAR will be launched aboard a Chinese satellite and operated at L-band with HH polarization. The purpose of the mission in consideration is dedicated to resources and environment uses, especially to natural disaster monitoring. The ground resolution is designed as 25 m x 25 m for detailed mode and 100 m x 100 m for wide scan-SAR mode. The off-nadir angle can be varied from 20 to 40 deg. The key system concepts are introduced
    corecore