Direct Observation of Covalently Bound Clusters in Resonantly Stabilized Radical Reactions and Implications for Carbonaceous Particle Growth.

Based on quantum mechanically guided experiments that observed elusive intermediates in the domain of inception that lies between large molecules and soot particles, we provide a new mechanism for the formation of carbonaceous particles from gas-phase molecular precursors. We investigated the clustering behavior of resonantly stabilized radicals (RSRs) and their interactions with unsaturated hydrocarbons through a combination of gas-phase reaction experiments and theoretical calculations. Our research directly observed a sequence of covalently bound clusters (CBCs) as key intermediates in the evolution from small RSRs, such as benzyl (C7H7), indenyl (C9H7), 1-methylnaphthyl (1-C11H9), and 2-methylnaphthyl (2-C11H9), to large polycyclic aromatic hydrocarbons (PAHs) consisting of 28 to 55 carbons. We found that hydrogen abstraction and RSR addition drive the formation and growth of CBCs, leading to progressive H-losses, the generation of large PAHs and PAH radicals, and the formation of white smoke (incipient carbonaceous particles). This mechanism of progressive H-losses from CBCs (PHLCBC) elucidates the crucial relationship among RSRs, CBCs, and PAHs, and this study provides an unprecedentedly seamless path of observed assembly from small RSRs to large nanoparticles. Understanding the PHLCBC mechanism over a wide temperature range may enhance the accuracy of multiscale models of soot formation, guide the synthesis of carbonaceous nanomaterials, and deepen our understanding of the origin and evolution of carbon within our galaxy.

Socioeconomic Status Impacts the Prognosis of Chronic Rhinosinusitis Treated by Endoscopic Sinus Surgery: An Observational Cohort Study in Northeast China.

Objective: To explore the association between socioeconomic status (SES) and postoperative outcomes in patients with chronic sinusitis (CRS) after functional endoscopic sinus surgery (ESS). Methods: We conducted an observational cohort study of 1,047 patients with CRS undergoing ESS. Discharged patients were followed up to 72 weeks for all-cause recurrence events. Baseline SES was established based on occupation, education level, and family income of the patients 1 year before the operation. Kaplan-Meier method was used to calculate the recovery rate after ESS, and Cox proportional hazards regression analysis was used to evaluate the relationship between SES and prognosis. Results: Patients of middle SES had lower unadjusted all-cause recurrence than those of low or high SES; 24-week overall recovery rate was 90.4% [95 % confidence interval ( CI): 89.6%-91.2%] in patients of middle SES, 13.5% (95 % CI: 12.8%-14.2%) in patients of low SES, and 31.7% (95 % CI: 30.7%-32.7%) in patients of high SES (both log-rank P < 0.001). After adjustment for covariates, hazard ratios ( HRs) were 7.69 (95 % CI: 6.17-9.71, P trend < 0.001) for all-cause recurrence for low SES versus middle SES, and 6.19 (95 % CI: 4.78-7.93, P trend < 0.001) for middle SES versus high SES. Conclusion: Low SES and high SES were more associated with the worse prognosis of CRS patients after ESS than middle SES.

Gain equalization for a few-mode erbium-doped fiber amplifier supporting eight spatial modes.

A trench-assisted ring few-mode erbium-doped fiber amplifier (FM-EDFA) supporting eight spatial modes is designed and proposed in this work. The gain equalization for the FM-EDFA is achieved by selecting the appropriate doping radius and concentration using a particle swarm optimization (PSO) algorithm when only the pump in the fundamental mode (L P 01) is applied. When the signals in the eight spatial modes are simultaneously amplified, the average modal gain is about 20 dB, and the DMG is less than 0.3 dB for a signal at 1550 nm. Considering the gain competition of six wavelength signals, the modal gain and DMG are more than 20 and 1 dB, respectively. In addition, the tolerance analysis for manufacturing with this design is also discussed. For a fluctuation in the refractive index, the average modal gain is about 19.5 dB, and the DMG is 0.77 dB, indicating that the structure has good fabrication tolerance.

Rapid Segmentation and Diagnosis of Breast Tumor Ultrasound Images at the Sonographer Level Using Deep Learning.

BACKGROUND: Breast cancer is one of the most common malignant tumors in women. A noninvasive ultrasound examination can identify mammary-gland-related diseases and is well tolerated by dense breast, making it a preferred method for breast cancer screening and of significant clinical value. However, the diagnosis of breast nodules or masses via ultrasound is performed by a doctor in real time, which is time-consuming and subjective. Junior doctors are prone to missed diagnoses, especially in remote areas or grass-roots hospitals, due to limited medical resources and other factors, which bring great risks to a patient's health. Therefore, there is an urgent need to develop fast and accurate ultrasound image analysis algorithms to assist diagnoses. METHODS: We propose a breast ultrasound image-based assisted-diagnosis method based on convolutional neural networks, which can effectively improve the diagnostic speed and the early screening rate of breast cancer. Our method consists of two stages: tumor recognition and tumor classification. (1) Attention-based semantic segmentation is used to identify the location and size of the tumor; (2) the identified nodules are cropped to construct a training dataset. Then, a convolutional neural network for the diagnosis of benign and malignant breast nodules is trained on this dataset. We collected 2057 images from 1131 patients as the training and validation dataset, and 100 images of the patients with accurate pathological criteria were used as the test dataset. RESULTS: The experimental results based on this dataset show that the MIoU of tumor location recognition is 0.89 and the average accuracy of benign and malignant diagnoses is 97%. The diagnosis performance of the developed diagnostic system is basically consistent with that of senior doctors and is superior to that of junior doctors. In addition, we can provide the doctor with a preliminary diagnosis so that it can be diagnosed quickly. CONCLUSION: Our proposed method can effectively improve diagnostic speed and the early screening rate of breast cancer. The system provides a valuable aid for the ultrasonic diagnosis of breast cancer.

Serum levels of lead are associated with venous thromboembolism: a retrospective study based on the NHANES database (1999 to 2018).

Background: Venous thromboembolism (VTE) is a common clinical problem. While lead toxicity is known to affect the nervous, hematopoietic system, skeletal, and cardiovascular system, the relationship between blood lead levels and VTE remains unclear. This study explored whether there is a correlation between the levels of serum lead and VTE through a retrospective analysis based on data from the National Health and Nutrition Examination Survey (NHANES), so as to provide a reference for follow-up research and clinical practice. Methods: According to the inclusion and exclusion criteria, subjects were enrolled from the NHANES (1999 to 2018) database and divided into a VTE group and a non-VTE group. The factors related to VTE were analyzed by single factor and multiple factor logistic regression analysis. Results: A total of 31,081 subjects were included, of which 59 had VTE (0.19%). The higher the levels of serum lead, the higher the incidence of VTE. The univariate analysis revealed that age, male sex, history of cigarette use, hypertension, diabetes, and serum lead levels were factors associated with VTE in the population from the NHANES database. Further multivariate analysis revealed that age, history of cigarette use, hypertension, diabetes, and serum lead levels were factors associated with VTE. Conclusions: The findings of this study suggest that higher serum levels of lead may be associated with VTE.

Elucidating the toluene formation mechanism in the reaction of propargyl radical with 1,3-butadiene.

Toluene is one of the simplest mono-substituted benzene derivatives and an important precursor to form polycyclic aromatic hydrocarbons (PAHs) and soot. However, there is a lack of critical understanding of the formation mechanisms of the toluene molecule. In this work, we explore high-temperature reactions of propargyl radical addition to 1,3-butadiene in a tubular flow microreactor. We obtain experimental evidence for the distinct formations of three C7H8 isomers consisting of toluene, 1,3,5-cycloheptatriene, and 5-methylene-1,3-cyclohexadiene discriminated by synchrotron VUV photoionization efficiency curves. Toluene is identified as the dominant product, which shows strong contrast with the calculated results of the system. By performing theoretical calculations and kinetic simulations, we found that 5-methylene-1,3-cyclohexadiene is a key product of the primary reaction, and toluene formation is enhanced by unavoidable secondary reactions, such as unimolecular isomerization and/or H-assisted isomerization reactions in the SiC microreactor. The current work provides competitive pathways for the enhanced formation of toluene, and may further help disentangle the toluene-promoted molecular growth mechanism of PAHs in combustion environments.

Single-photon ionization induced C-C or C-N bond formation in pyrrole clusters.

The formation of photodimers of nitrogen heterocyclic compounds (NHCs) can partially explain the DNA damage due to radiation. Pyrrole and its derivatives, as major components of DNA, are used to understand the phenomena at the molecular level. With the aid of vacuum ultraviolet (VUV)-infrared (IR) spectroscopy and theoretical calculations, herein, we explore the possibility of the formation of a new C-C or C-N bond in pyrrole (py) clusters in a supersonic jet after single-photon ionization. Both neutral (py)2 and (py)3 clusters are stabilized by multiple interactions, such as N-H⋯π hydrogen bonds and π⋯π interactions. With 118 nm light ionization of the (py)2, we elucidate that the two py are more inclined to be stabilized by a newly formed C-C or C-N covalent bond, besides the π-stacked parallel structure of (py)2+. The (py)3+ with a C-C or C-N covalent bonded (py)2+ core mainly contributes to the IR spectrum of (py)3+. The present results are helpful to elucidate the mechanism of DNA damage at a molecular level.

Closed Bipolar Electrode Array for Optical Reporting Reaction-Coupled Electrochemical Sensing and Imaging.

This review centers on a closed bipolar electrode (BPE) array using an electro-fluorochromism (EFC) or electro-chemiluminescence (ECL) reaction as the reporting reaction. Electrochemical signals at one pole of the closed BPE array can be transduced into the EFC or ECL signals at the opposite pole. Therefore, the current signal of a redox reaction can be easily detected and imaged by monitoring the luminescence signal. Recent developments in closed BPE array-based EFC and ECL sensing and imaging are summarized and discussed in detail. Finally, we consider the challenges and opportunities for improving the spatial resolution of closed BPE array-based electrochemical imaging, and emphasize the important application of this technique to the imaging of cellular activities at the single-cell level.

Discriminating between the dissociative photoionization and thermal decomposition products of ethylene glycol by synchrotron VUV photoionization mass spectrometry and theoretical calculations.

Understanding the combustion chemistry of biofuel compounds is of great importance in the intelligent selection of next-generation alternative fuels. Ethylene glycol (C6H10O2) is a prototypical representative of potential biofuels. In this work, the thermal decompositions along with the dissociative ionization of ethylene glycol are studied by synchrotron VUV photoionization mass spectrometry. As a part of the dissociative ionization study, the appearance energies of seven fragments are measured. Using the theoretical calculation results, the possible formation channels of these fragments are proposed. In particular, the productions of CH3OH+ and CH3OH2+ are suggested to be from the isomerization/dissociation process, where double proton transfer processes are highlighted. Using a tunable VUV source, the high-temperature pyrolysis products of ethylene glycol are differentiated from the dissociative ionization products. Specifically, two isomeric products vinyl alcohol and acetaldehyde by H2O elimination are obtained. Formaldehyde and methanol from direct C-C bond cleavage are identified. The fragmentations of fragile radicals such as hydroxymethyl, methoxy and ethoxy are used to explain the missing products from the direct C-C and C-O bond dissociation reactions. There is no experimental evidence for the occurrence of the H and H2 elimination reactions which may have not been accessed under the present temperature conditions.

Healthcare quality and safety assessment based on annual scorekeeping.

Objective: To explore the practice of medical quality and safety evaluation system based on annual score under the background of establishing modern hospital management system and strengthening national public hospital performance evaluation. Methods: Statistical analysis was used to study the improvement of medical quality and safety in hospitals after the implementation of score evaluation, and the existing problems were analyzed according to the actual situation and related requirements. Results: The hospital's medical quality and safety evaluation system ran smoothly, the evaluation indexes could be implemented, and the evaluation results were used properly. The improvement of hospital medical quality and operation efficiency has achieved good results. Conclusion: The evaluation system of medical quality and safety for physicians and medical technicians based on annual score can achieve the whole process, all-round, personalized and information-based evaluation, and promote the high-quality development of hospitals. It is necessary to further improve the range of evaluation and carry out the evaluation of the evaluation system by relevant personnel.

Infrared Spectroscopy of Stepwise Hydration Motifs of Sulfur Dioxide.

Experimental characterization of microscopic events and behaviors of SO2-H2O interactions is crucial to understanding SO2 atmospheric chemistry but has been proven to be very challenging due to the difficulty in size selection. Here, size-dependent development of SO2 hydrate structure and cluster growth in the SO2(H2O)n (n = 1-16) complexes was probed by infrared spectroscopy based on threshold photoionization using a tunable vacuum ultraviolet free electron laser. Spectral changes with cluster size demonstrate that the sandwich structure initially formed at n = 1 develops into cycle structures with the sulfur and oxygen atoms in a two-dimensional plane (n = 2 and 3) and then into three-dimensional cage structures (n ≥ 4). SO2 is favorably bound to the surface of larger water clusters. These stepwise features of SO2 hydration on various sized water clusters contribute to understanding the reactive sites and electrophilicity of SO2 on cloud droplets, which may have important atmospheric implications for studying the SO2-containing aerosol systems.

Disruption of hematopoiesis attenuates the osteogenic differentiation capacity of bone marrow stromal cells.

BACKGROUND: The homeostasis of mesenchymal stem cells (MSCs) is modulated by both their own intracellular molecules and extracellular milieu signals. Hematopoiesis in the bone marrow is maintained by niche cells, including MSCs, and it is indispensable for life. The role of MSCs in maintaining hematopoietic homeostasis has been fully elucidated. However, little is known about the mechanism by which hematopoietic cells reciprocally regulate niche cells. The present study aimed to explore the close relationship between MSCs and hematopoietic cells, which may be exploited for the development of new therapeutic strategies for related diseases. METHODS: In this study, we isolated cells from the offspring of Tie2Cre + and Ptenflox/flox mice. After cell isolation and culture, we investigated the effect of hematopoietic cells on MSCs using various methods, including flow cytometry, adipogenic and osteogenic differentiation analyses, quantitative PCR, western bloting, and microCT analysis. RESULTS: Our results showed that when the phosphatase and tensin homolog deleted on chromosome 10 (Pten) gene was half-deleted in hematopoietic cells, hematopoiesis and osteogenesis were normal in young mice; the frequency of erythroid progenitor cells in the bone marrow gradually decreased and osteogenesis in the femoral epiphysis weakened as the mice grew. The heterozygous loss of Pten in hematopoietic cells leads to the attenuation of osteogenic differentiation and enhanced adipogenic differentiation of MSCs in vitro. Co-culture with normal hematopoietic cells rescued the abnormal differentiation of MSCs, and in contrast, MSCs co-cultured with heterozygous null Pten hematopoietic cells showed abnormal differentiation activity. Co-culture with erythroid progenitor cells also revealed them to play an important role in MSC differentiation. CONCLUSION: Our data suggest that hematopoietic cells function as niche cells of MSCs to balance the differentiation activity of MSCs and may ultimately affect bone development.

The association between the dietary pattern in abdominal obesity based on visceral fat index and dyslipidaemia in the Henan Rural Cohort Study.

The present study aimed to explore the association between dietary patterns in abdominal obesity obtained by reduced-rank regression (RRR) with visceral fat index (VFI) as a dependent variable and dyslipidemia in rural adults in Henan, China. A total of 29538 people aged 18-79 were selected from the Henan Rural Cohort Study. RRR analysis was used to identify dietary patterns; logistic regression analysis and restricted cubic spline regression models were applied to analyze the association between dietary patterns in abdominal obesity and dyslipidemia. VFI was used as a mediator to estimate the mediation effect. The dietary pattern in abdominal obesity was characterized by high carbohydrate and red meat intake and low consumption of fresh fruits, vegetables, milk, etc. After full adjustment, the highest quartile of dietary pattern scores was significantly associated with an increased risk of dyslipidemia (OR: 1·33, 95 % CI 1·23-1·44, Ptrend < 0·001), there was a non-linear dose-response relationship between them (Poverall-association < 0·001, Pnon-lin-association = 0·022). The result was similar in dose-response between the dietary pattern scores and VFI. The indirect effect partially mediated by VFI was significant (OR: 1·07, 95 % CI 1·06-1·08). VIF explained approximately 53·3 % of odds of dyslipidemia related to the dietary pattern. Abdominal obesity dietary pattern scores positively affected VFI and dyslipidemia; there was a dose-response in both relationships. Dyslipidemia progression increased with higher abdominal obesity dietary pattern scores. In addition, VFI played a partial mediating role in relationship between abdominal obesity dietary pattern and dyslipidemia.

Increased UBE2L6 regulated by type 1 interferon as potential marker in TB.

The aim of this study is to identify potential biomarker of tuberculosis (TB) and determine its function. Differentially expressed mRNAs(DEGs) were selected from a blood database GSE101805, and then, 30 key genes were screened using STING, Cytoscape and further functionally enriched. We then found that only 6 of 13 genes related to ubiquitination (the first in the functional enrichment) were increased significantly. ROC analysis showed that UBE2L6, among 6 genes, had the highest diagnostic value, and then, we found that it also had mild value in differential diagnosis. Moreover, our analysis showed that UBE2L6 may be upregulated by type I interferon, which was further confirmed by us. In addition, we also found that UBE2L6 inhibits the apoptosis of Mycobacterium tuberculosis(Mtb)infected macrophages. Subsequently, we discovered that miR-146a-5p, which may target UBE2L6, is reduced in peripheral blood mononuclear cells (PBMC) and plasma of TB, and it also had certain diagnostic efficiency(AUC=0.791). In brief, we demonstrated that UBE2L6 as well as miR-146a-5p is a potential biomarker for TB and UBE2L6,which may also plays important role in TB by, at least, modulating Mtb-infected macrophage apoptosis.

Association of Serum Glucocorticoids with Various Blood Pressure Indices in Patients with Dysglycemia and Hypertension: the Henan Rural Cohort Study.

OBJECTIVE: To our knowledge, no definitive conclusion has been reached regarding the relationship between glucocorticoids and hypertension. Here, we aimed to explore the characteristics of glucocorticoids in participants with dysglycemia and hypertension, and to analyze their association with blood pressure indicators. METHODS: The participants of this study were from the Henan Rural Cohort study. A total of 1,688 patients 18-79 years of age were included in the matched case control study after application of the inclusion and exclusion criteria. Statistical methods were used to analyze the association between glucocorticoids and various indices of blood pressure, through approaches such as logistic regression analysis, trend tests, linear regression, and restricted cubic regression. RESULTS: The study population consisted of 552 patients with dysglycemia and hypertension (32.7%). The patients with co-morbidities had higher levels of serum cortisol ( P = 0.009) and deoxycortisol ( P < 0.001). The adjusted odds ratios (and 95% confidence intervals) for dysglycemia with hypertension were 1.55 (1.18, 2.04) for the highest tertile of Ln-cortisol compared with the lowest tertile. Additionally, the highest Ln-deoxycortisol levels were associated with increased prevalence of dysglycemia with hypertension by 159% (95% confidence interval: 122%, 207%). CONCLUSIONS: Serum deoxycortisol was positively correlated with systolic blood pressure, pulse pressure, mean arterial pressure, mean blood pressure, and mean proportional arterial pressure. Glucocorticoids (deoxycortisol and cortisol) increase the risk of hypertension in people with dysglycemia, particularly in those with T2DM.

Small Solitary Ground-Glass Nodule on CT as an Initial Manifestation of Coronavirus Disease 2019 (COVID-19) Pneumonia.

The 2019 novel coronavirus (2019-nCoV) outbreak in Wuhan, Hubei Province, China in 2019 led to large numbers of people being infected and developing atypical pneumonia (coronavirus disease 2019, COVID-19). Typical imaging manifestations of patients infected with 2019-nCoV has been reported, but we encountered an atypical radiological manifestation on baseline computed tomography (CT) images in three patients from Wuhan, China infected with the 2019-nCoV. Surprisingly, the only similar CT finding was a solitary sub-centimeter ground-glass nodule adjacent to bronchovascular bundles, which could be easily overlooked. In addition, the follow-up images in these patients showed how COVID-19 pneumonia evolved from these small nodules. The radiologic manifestation of the three cases will expand contemporary understanding of COVID-19.

A microwave spectroscopic and ab initio study of keto-enol tautomerism and isomerism in the cyclohexanone-water complex.

Cyclohexanone and water are two important components of secondary organic aerosol (SOA), and understanding the intermolecular interactions between these two species can provide insight to the initial formation mechanism of SOA particles. In this work, we have investigated the keto-enol tautomeric and conformational changes of the cyclohexanone monomer and its monohydrate by Fourier-transform microwave spectroscopy and ab initio calculations. Chirped-pulse and cavity-based FTMW spectrometers in the region of 7-14 GHz were used to measure rotational spectra of the most stable species prepared in a cold molecular beam. The experimental and theoretical results suggest that the chair conformer of the keto tautomer is the most stable structure. We have measured and assigned rotational spectra of ten isotopologues, including all six single 13C substitutions observed in natural abundance and four different isotopic species of water (H2O, D2O, DOH and HOD). The experimental structure of cyclohexanone-water was determined directly using this isotopic information. The analysis reveals the existence of both canonical and secondary hydrogen bonding, which we confirm using QTAIM analyses. To further elucidate the hydrogen bonding characteristics in ketone-water clusters, cyclohexanone-water is compared to a variety of other hydrated ketones, namely formaldehyde, acetone, cyclobutanone, and cyclopentanone, through utilization of the symmetry adapted perturbation theory (SAPT) energy decomposition method. The results of this study shed light on the effects of water on keto-enol tautomerization, and the role of hydrogen bonding in ketone monohydrates and the formation of related SOA particles.