Response characteristics of MAPbBr3 direct conversion X-ray detectors based on measurements and Monte Carlo simulation.

In recent years, higher requirements have been placed on the response characteristics of X-ray detectors in the field of medical diagnostic imaging. Due to this, high sensitivity, high attenuation coefficient and low cost detection materials need to be developed. In this paper, the geometric model of a detector was established by Geant4 code. The absorption efficiency and mass attenuation coefficient of MAPbBr3 crystals were calculated in the energy range of 30 keV to 100 keV. Compared with the mass attenuation coefficient of the NIST database, the deviation was within 1.39%. The signal charge number and detection sensitivity of the X-ray interaction with the MAPbBr3 crystal ware calculated. Compared with the CdTe crystal and α-Se, the MAPbBr3 crystal still had a larger detection sensitivity under a smaller applied electric field, which was approximately 9 times higher than that of α-Se. This result indicated that the detection sensitivity could be greatly improved by using a high atomic number and high charge mobility-lifetime product. Based on the simulation results, the 2 mm thick MAPbBr3 crystal exhibited the highest detection sensitivity at 60 keV X-rays, which was in agreement with the experimental results.

Associations Between Gut Microbiota and Asthma Endotypes: A Cross-Sectional Study in South China Based on Patients with Newly Diagnosed Asthma.

OBJECTIVE: This study aimed to investigate the gut microbiome profile in different inflammatory phenotypes of treatment-naive newly diagnosed asthmatic adults, to gain insight on the associations between intestinal microbiota and phenotypic features that characterize asthma heterogeneity to develop new treatments for asthma. METHODS: Fresh stool samples were obtained from 20 healthy subjects and 47 newly diagnosed asthmatic patients prior to any interventions. The asthmatics were divided into allergic and non-allergic cohorts. Intestinal microbiota was analyzed by 16S rRNA next-generation sequencing. Demographic and clinical parameters were collected. Alpha and beta diversity analysis were calculated to detect differences within sample phylotype richness and evenness between controls and asthmatic patients. Statistically significant differences between samples were analyzed for all used metrics, and features of gut bacterial community structure were evaluated in relation to extensive clinical characteristics of asthmatic patients. RESULTS: Gut microbial compositions were significantly different between asthmatic and healthy groups. Alpha-diversity of the gut microbiome was significantly lower in asthmatics than in controls. The microbiome between allergic and non-allergic asthmatic patients were also different, and 28 differential species were identified. PPAR signaling pathway, carotenoid biosynthesis, and flavonoid biosynthesis were significantly positively correlated with allergy-associated clinical index, including FENO value, blood eosinophil counts, and serum IgE and IL-4 levels. A combination of Ruminococcus bromii, Brevundimonas vesicularis, and Clostridium disporicum showed an AUC of 0.743 in the specific allergic/non-allergic cohort. When integrating C. disporicum, flavone, flavonol biosynthesis, and serum IL-4 values, the AUC achieved 0.929 to classify asthmatics. At the same time, C. colinum and its associated functional pathway exhibited an AUC of 0.78 to distinguish allergic asthmatics from those without allergies. CONCLUSION: We demonstrated a distinct taxonomic composition of gut microbiota in different asthmatic phenotypes, highlighting their significant relationships. Our study may support considerations of intestinal microbial signatures in delineating asthma phenotypes.

Endoscopic treatment of pouch inlet and afferent limb strictures: stricturotomy vs. balloon dilation.

BACKGROUND: Strictures are common complications after ileal pouch surgery. The aim of this study is to evaluate the efficacy and safety of endoscopic stricturotomy vs. endoscopic balloon dilation (EBD) in the treatment of pouch inlet strictures. METHODS: All consecutive ulcerative colitis patients with the diagnosis of pouch inlet or afferent limb strictures treated in our Interventional Inflammatory Bowel Disease Unit (i-IBD) from 2008 to 2017 were extracted. The primary outcomes were surgery-free survival and post-procedural complications. RESULTS: A total of 200 eligible patients were included in this study, with 40 (20.0%) patients treated with endoscopic stricturotomy and 160 (80.0%) patients treated with EBD. Symptom improvement was recorded in 11 (42.3%) patients treated with endoscopic stricturotomy and 16 (13.2%) treated with EBD. Subsequent surgery rate was comparable between the two groups (9 [22.5%] vs. 33 [20.6%], P = 0.80) during a median follow-up of 0.6 years (interquartile range [IQR] 0.4-0.8) vs. 3.6 years (IQR 1.1-6.2) in patients receiving endoscopic stricturotomy and EBD, respectively. The overall surgery-free survival seems to be comparable as well (P = 0.12). None of the patients in the stricturotomy group developed pouch failure, while 9 patients (5.6%) had pouch failure in the balloon dilation group (P = 0.17). Procedural bleeding was seen in three occasions (4.7% per procedure) in patients receiving endoscopic stricturotomy and perforation was seen in three occasions (0.8% per procedure) in patients receiving EBD (P = 0.02). In multivariable analysis, an increased length of the stricture (hazard ratio [HR] 1.4, 95% confidence interval [CI] 1.0-1.8) and concurrent pouchitis (HR 2.5, 95% CI 1.0-5.7) were found to be risk factors for the requirement of surgery. CONCLUSION: Endoscopic stricturotomy and EBD were both effective in treating patients with pouch inlet or afferent limb strictures, EBD had a higher perforation risk while endoscopic stricturotomy had a higher bleeding risk.

Strategies and recommendations for the management of gastrointestinal surgery during the COVID-19 pandemic: experience shared by Chinese surgeons.

Novel coronavirus disease-2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is an ongoing public-health pandemic worldwide. Although SARS-CoV-2 has been known to spread primarily through respiratory droplets, recent evidence also supports fecal/oral as an additional route of transmission, raising concerns over gastrointestinal (GI) transmission of the infection. Herein, we, as the front-line Chinese GI surgeons, would like to share our experience and lessons in the combat against COVID-19. It is essential to create science-based, rational, and practical strategies during the outbreak of COVID-19. Here, we provide multi-institutional consensus on minimizing disease transmission while continuing to provide care from all aspects for patients in GI surgery, including outpatient clinics, inpatient units, gastrointestinal endoscopy centers, and adjustments in perioperative care. Our experiences and recommendations are worth sharing and may help to establish specific infection-control and outcome measures.

RESEARCH ON THE ABSOLUTE MEASUREMENT AND CALIBRATION METHODS OF (250-450) KV X-RAY AIR KERMA AT NIM.

With the rapid application of nuclear technology, radiation protection is becoming more and more important. For external radiation protection, most of the national metrology institutes in the world have established the primary standard of X-ray air kerma in (10-250) kV and Cs-137 gamma ray, but the energy between 250 and 662 keV needs the establishment of traceability. To provide solution to such issue, a graphite cavity ionization chamber was constructed at National Institute of Metrology to measure the air kerma in (250-450) kV X-ray. The relative standard uncertainty of the method is 0.45%. Two different types of ionization chambers were used to measure the air kerma of N-300 radiation quality, and the result has a deviation of 0.09%.

Deoxynivalenol Induces Intestinal Damage and Inflammatory Response through the Nuclear Factor-κB Signaling Pathway in Piglets.

Deoxynivalenol (DON) is highly toxic to animals and humans, but pigs are most sensitive to it. The porcine mucosal injury related mechanism of DON is not yet fully clarified. Here, we investigated DON-induced injury in the intestinal tissues of piglet. Thirty weanling piglets [(Duroc × Landrace) × Yorkshire] were randomly divided into three groups according to single factor experimental design (10 piglets each group). Piglets were fed a basal diet in the control group, while low and high dose groups were fed a DON diet (1300 and 2200 µg/kg, respectively) for 60 days. Scanning electron microscopy results indicated that the ultrastructure of intestinal epithelial cells in the DON-treated group was damaged. The distribution and optical density (OD) values of zonula occludens 1 (ZO-1) protein in the intestinal tissues of DON-treated groups were decreased. At higher DON dosage, interleukin (IL)-1ß, IL-6, and tumor necrosis factor-α mRNA levels were elevated in the intestinal tissues. The mRNA and protein levels of NF-κB p65, IκB-α, IKKα/ß, iNOS, and COX-2 in the small intestinal mucosa were abnormally altered with an increase in DON concentration. These results indicate that DON can persuade intestinal damage and inflammatory responses in piglets via the nuclear factor-κB signaling pathway.

Effects of deoxynivalenol exposure on cerebral lipid peroxidation, neurotransmitter and calcium homeostasis of chicks in vivo.

During current research, the effects of deoxynivalenol (DON) exposure on cerebral lipid peroxidation, neurotransmitter secretion and calcium homeostasis in chicks were evaluated. One hundred and twenty Hailan chicks (male, 1-day-old) were randomly divided into four groups. Chicks in low, medium and high dose groups were fed with 0.27, 1.68 and 12.21 mg/kg-1 DON respectively by gavage according to feed intake. Chicks in control group were fed with physiological saline by gavage. The trials were conducted for 36 d. At the end of the trials, twenty chicks per group were sacrificed, and the cerebra were collected for measuring the brain indices. Compared with the control group, the activities of total superoxide dismutase (T-SOD) and glutathione peroxidase were significantly decreased in treatment groups (P < 0.05), the contents of malondialdehyde in high dose group were increased (P < 0.05), the catalase activities and nitric oxide contents in medium and high dose groups were decreased (P < 0.05), and the activities of T-AOC in high dose group were reduced (P < 0.05). Compared with the control group, the concentrations of norepinephrine and 5-hydroxytryptamine in high dose group were obviously increased (P < 0.05), while the concentrations of dopamine were decreased (P < 0.05). Meanwhile, the concentrations of calcium and calmodulin (CaM) in medium and high dose groups were lower than those of the control group (P < 0.05), and the gene relative expression of CaM mRNA in treatment groups were significantly reduced (P < 0.05), in a dose-dependent manner. These results suggested that DON exposure can affect the cerebral lipid peroxidation, neurotransmitters secretion and the balance of calcium homeostasis in chicks.

A sensitive immunochromatographic assay using colloidal gold-antibody probe for rapid detection of fumonisin B1 in corn.

A sensitive immunochromatographic assay (ICA) using a colloidal gold-antibody probe for the rapid detection of fumonisin B1 (FB1) in corn samples was developed. The colour density of the test line correlated with the concentration of FB1 in the range 2-40 ng ml(-1) by the assay, and the detection limit for FB1 was 2 ng ml(-1). The linear range for FB1 was 50-1000 µg kg(-1), and the visual limit detection of the test was 1000 µg kg(-1) in corn samples. The ICA to detect FB1 is sensitive, specific and rapid. Specific anti-FB1 monoclonal antibody (mAb) and FB1-ovalbumin (FB1-OVA) conjugate antigen were prepared. FB1 mAb, labelled with colloidal gold, was used as the probe on the immunochromatographic strip. FB1-OVA and goat-anti-mouse IgG were coated onto a nitrocellulose (NC) membrane as test lines and control lines, respectively. FB1 in samples will competitively combines the FB1 mAb with the FB1-OVA in an NC membrane and the results are directly observed by the colour of the detection and quality control lines. The concentrations of FB1 mAb labelled with colloidal gold, detecting antigen and goat anti-mouse IgG, were optimised. The results indicate that the test strip is specific for FB1, with no cross-reactivity to other toxins. The strip assay for FB1 was simple, only needing one step without complicated assay performance and expensive equipment, and the total time for visual evaluation was less than 10 min. A survey of 24 corn samples from Hefei, China, was performed with the test strip and HPLC, and the detection results showed that the developed ICA and the HPLC were in excellent agreement. Hence, the developed ICA can be used as a method for rapid detection of FB1 in corn samples.

The in vitro protective effects of curcumin and demethoxycurcumin in Curcuma longa extract on advanced glycation end products-induced mesangial cell apoptosis and oxidative stress.

Curcuma longa L. (CLL), a traditional herbal medicine, has been widely used for the prevention of diabetic vascular complications in recent years. However, the protective effects of curcuminoids in CLL on the AGEs-induced damage to mesangial cell are not fully understood. In this present study, dihydroethidium, superoxide dismutase kit, malondialdehyde kit, and acridine orange/ethidium bromide staining methods were used to evaluate the activities of curcumin and demethoxycurcumin (10(-11)-10(-9) M) on AGEs-induced oxidative stress and apoptosis, which were associated with the damage to mesangial cell. The results showed that these two compounds could significantly restore advanced glycation end products (AGEs)-induced apoptosis to normal levels (IC50 = 3.874 × 10(-11) M for curcumin and IC50 = 6.085 × 10(-11) M for demethoxycurcumin) and reduce remarkably reactive oxygen species generation in mesangial cell. Furthermore, curcumin and demethoxycurcumin dramatically elevated AGEs-decreased superoxide dismutase activity while significantly reducing AGEs-increased malondialdehyde content in cell culture supernatant. Our results suggest that both curcumin and demethoxycurcumin have a significant protective potential to the prevention of diabetic nephropathy.