Search

Amino acids are the building blocks of proteins and are widely used as important ingredients for other nitrogen‐containing molecules. Here, we report the sustainable production of amino acids from biomass‐derived hydroxy acids with high activity under visible‐light irradiation and mild conditions, using atomic ruthenium‐promoted cadmium sulfide (Ru1/CdS). On a metal basis, the optimized Ru1/CdS exhibits a maximal alanine formation rate of 26.0 molAla ⋅ gRu−1 ⋅ h−1, which is 1.7 times and more than two orders of magnitude higher than that of its nanoparticle counterpart and the conventional thermocatalytic process, respectively. Integrated spectroscopic analysis and density functional theory calculations attribute the high performance of Ru1/CdS to the facilitated charge separation and O−H bond dissociation of the α‐hydroxy group, here of lactic acid. The operando nuclear magnetic resonance further infers a unique "double activation" mechanism of both the CH−OH and CH3−CH−OH structures in lactic acid, which significantly accelerates its photocatalytic amination toward alanine. [ABSTRACT FROM AUTHOR]

Regulating the microenvironment of active sites is crucial to boost the performance of direct propene epoxidation with H2 and O2. Herein, the enhanced surface transfer of H2O2 intermediates was first achieved by sodium‐decorated Au‐Ti bifunctional active sites. Combined with multi‐techniques (e.g., operando UV–vis–NIR system, DFT studies and quantitative model calculations), it is found that the sodium‐decorated silanols (Si‐ONa species) on the TS‐1 support enhance the formation of Ti‐OOH intermediates by restraining H2O2 decomposition. In addition, sodium‐decorated silanols improves the desorption of propylene oxide, suppressing its ring‐opening and formation for the carbonaceous deposits. Moreover, the sodium‐decorated Au nanoparticles with smaller diameter and higher electron density further strengthen O2 adsorption and boost the H2O2 formation. This work not only provides fundamental understandings on the microenvironment of Au‐Ti bifunctional catalysts but also sheds new light on enhancing the performance by boosting the surface molecular transfer. [ABSTRACT FROM AUTHOR]

Rational screening of efficient supported metal catalysts is still a great challenge due to the complicated reaction mechanism for selective polyol oxidation. Exemplifying glycerol oxidation to glyceric acid as a model reaction, we perform a DFT assisted descriptor based microkinetic modeling to reveal the underlying mechanism. It is found that the addition/formation of OH− could polarize the metal surface (M‐OH*) to regulate the d‐band center of Pt accompanied by the electron transfer from OH− to metal atoms, thus promoting the adsorption of glycerol. Moreover, the linear chemisorption energy and transition state energy scaling relations are well established on the formation energies of adsorbed C and O. Activity map obtained from descriptor based microkinetic analysis demonstrates that Pt and Ir metals exhibit the highest catalytic activity. Meanwhile, further analysis of the desorption energy and CC bond cleavage activation energy of glyceric acid product shows that Au and Pt metals display the optimal glyceric acid selectivity. Satisfactorily, these results from microkinetic analysis are in good agreement with the comparative experimental results. The insights revealed here may open a new avenue for rational design of transition metal catalysts in the bio‐polyol oxidation system. [ABSTRACT FROM AUTHOR]

To investigate the clinical significance of abnormal human telomerase RNA gene component (hTERC) gene amplification tested by fluorescence in situ hybridization in cervical lesions.In 373 patients with cytologic abnormalities, high-risk human papilomavirus (HR-HPV) was detected by the hybrid capture II method, and abnormal amplification of the hTERC gene in exfoliated cells was detected by fluorescence in situ hybridization.Cell smear findings suggested atypical squamous cells in 148 patients, low-grade squamous intraepithelial lesion in 62 patients, and high-grade squamous intraepithelial lesion in 107 patients, squamous cell carcinoma in 56 patients, and cervical biopsy-revealed inflammation in 89 patients, cervical intraepithelial neoplasia (CIN) I in 36 patients, CIN II in 43 patients, CIN III in 129 patients, and infiltrating carcinoma in 76 patients. In the inflammation, CIN I, CIN II, CIN III, and infiltrating carcinoma groups, the infection rates of HR-HPV were 29.21%, 52.78%, 74.42%, 92.25%, and 93.42% (P < 0.01), respectively; the positive rates of hTERC gene amplification were 0.00%, 13.89%, 41.86%, 78.29%, and 89.47% (P < 0.01), respectively. With respect to advanced cervical lesions (≥CIN II), cytology (≥ low-grade squamous intraepithelial lesion), HR-HPV testing, and hTERC testing differed insignificantly in the negative predictive value (P > 0.05), but they differed significantly in the sensitivity, specificity, and positive predictive value (P < 0.01). Among the 3 methods, hTERC testing showed the highest specificity and positive predictive value, and HR-HPV testing showed the highest sensitivity. In 41 patients with untreated CIN I and CIN II, the sensitivity of detection of hTERC gene amplification to predict lesion progression was 88.89%, and the specificity was 93.75%.Detection of abnormal amplification of the hTERC gene can assist in screening cervical lesions and identifying CIN I/II patients with a high progression risk. [ABSTRACT FROM AUTHOR]

Objective: To analyze the clinical characteristics in patients with persistent positive pharyngeal swab of 2019 novel coronavirus Omicron variant and results of nucleic acid testing of anal swabs to provide basis for prevention and control measures., Methods: This study included 93 patients whose pharyngeal swab nucleic acid test were persistent positive and admitted to the ward of Daping Hospital in the National Exhibition and Convention Center (Shanghai) Makeshift Hospital from May 1 to May 24, 2022. The gender, age, underlying diseases, vaccination status, clinical symptoms, interval between infection onset and anal sampling, length of hospital stay, the nucleic acid test result of pharyngeal swabs and anal swabs and the time turning negative were collected and analyzed., Results: The age of 93 patients ranged from 8 to 72 years old with a median of (46.0±16.0) years old. Among them, 30 cases (32.3%) were male and 63 cases (67.7%) were female. Sixty-five patients (69.9%) received 2-3 shots of vaccine, 2 patients (2.1%) received 1 shot, and 26 patients (28.0%) did not receive any vaccination. Twenty patients (21.5%) had underlying diseases, of which hypertension (13 cases, 14.0%) and type 2 diabetes mellitus (6 cases, 6.5%) were the most common. Twenty-four patients (25.8%) had asymptomatic infection and the rest (69 cases, 74.2%) had mild symptoms. Cough (50 cases, 53.8%) and sore throat (28 cases, 30.1%) were the most common clinical manifestations of the upper respiratory tract in these patients. Only 6 patients (6.5%) had gastrointestinal symptoms (including diarrhea in 5 patients and diarrhea with vomiting in 1 patient). Pharyngeal and anal swabs were collected simultaneously from all 93 patients at 8-16th days [(11.55±2.27) days] after 2019 novel coronavirus Omicron variant infection. The pharyngeal swabs were positive in 79 patients (85.0%) and the anal swabs were positive in 5 patients (5.4%). The time of pharyngeal swabs turning negative was (14.7±2.9) days, and that of anal swab turning positive was (14.2±1.9) days. The median length of hospital stay was (16.7±2.9) days., Conclusions: In patients with persistent positive nucleic acid of the 2019 novel coronavirus Omicron variant, there were more mild infection than asymptomatic. The upper respiratory tract symptoms such as cough and sore throat were the most. The likelihood of transmission of 2019 novel coronavirus Omicron variant through the digestive tract may be low. The correlation between gastrointestinal symptoms and 2019 novel coronavirus Omicron variant RNA in the digestive tract is uncertain.

Objectives: It was the aim of this study to investigate the feasibility of polymerase chain reaction (PCR)/ligase detection reaction (LDR)/capillary electrophoresis for the detection of paternally inherited fetal CD17 (A-->T) mutation of beta-thalassemia in maternal plasma., Methods: The target DNA in maternal plasma was amplified by PCR and the mutant signal was detected by LDR. Unique LDR products were produced and separated by capillary electrophoresis. PCR/LDR/capillary electrophoresis was applied to detect CD17 (A-->T) mutation in an experimental model at different sensitivity levels and from 3 maternal plasma samples., Results: The sensitivity of PCR/LDR/capillary electrophoresis for detecting low-abundance CD17 (A-->T) mutation was 1:5,000 at least. The technique was applied in maternal plasma DNA for detecting paternally inherited fetal CD17 (A-->T) mutation, and the results were concordant with that of PCR/reverse dot blot of amniotic fluid cell DNA., Conclusions: PCR/LDR/capillary electrophoresis has a very high sensitivity to distinguish low-abundance single nucleotide differences and probably detects paternally inherited fetal point mutations in maternal plasma., (Copyright 2009 S. Karger AG, Basel.)