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The crystal structure, mechanical stability, phonon dispersion, electronic transport properties and thermoelectric (TE) performance of the Bi2Sn2Te6 monolayer are assessed with the first-principles calculations and the Boltzmann transport theory. The Bi2Sn2Te6 monolayer is an indirect semiconductor with a band gap of 0.91 eV using the Heyd-Scuseria-Ernzerhof (HSE06) functional in consideration of the spin-orbit coupling (SOC) effect. The Bi2Sn2Te6 monolayer is high thermodynamically and mechanically stable by the assessments of elastic modulus, phonon dispersion curves, and ab initio molecular dynamics (AIMD) simulations. The hybrid bonding characteristics are discovered in Bi2Sn2Te6 monolayer, which is advantageous for phonon scattering. The antibonding interactions near the Fermi level weaken the chemical bonding and reduce the phonon vibrational frequency. Due to the short phonon relaxation time, strong anharmonic scattering, large Grüneisen parameter, and small phonon group velocity, an ultralow lattice thermal conductivity (0.27 W/(m·K)@300K) is achieved for the Bi2Sn2Te6 monolayer. The optimal dimensionless figure of merit (ZT) values for the n-type and p-type Bi2Sn2Te6 monolayers are 2.68 and 1.63 at 700 K, respectively, associated with a high TE conversion efficiency of 20.01% at the same temperature. Therefore, the Bi2Sn2Te6 monolayer emerges as a promising candidate for TE material with high conversion efficiency. [ABSTRACT FROM AUTHOR]

Helicobacter pylori (H. pylori) resistance is the most important risk factor for eradication failure. However, in most regions, antibiotic resistance rates of H. pylori in patients with different types of gastric mucosal lesions are still unclear. An 8-year clinical retrospective cohort study involving 2847 patients was performed. In this study, we first summarized and compared the resistance status of H. pylori in different years, ages, sexes, and gastric diseases. The resistance profiles of amoxicillin (AMX), clarithromycin (CLR), levofloxacin (LVX) and furazolidone (FR) and their changing trends in the clinic were described. Then, multiple antibiotic resistance in different gastric diseases and years were described and compared. The relationship between proton pump inhibitor (PPI) medication history and antibiotic resistance in H. pylori was also explored. Finally, an antibiotic resistance risk model was constructed for clinical resistance risk prediction. The overall resistance rates of AMX, CLR, LVX and FR in gastric diseases were 8.18%, 38.11%, 43.98%, and 13.73%, respectively. The mono resistance, double resistance, triple resistance, and quadruple resistance rates were 30.17%, 25.96%, 6.46%, and 0.63%, respectively. Compared with the period from 2014 to 2016, the rates of mono-resistance and multiple resistance all showed relatively downward trends in the past 5 years. Factors including age, sex, type of gastric lesions and recent PPI treatment history are associated with the antibiotic resistance rate of H. pylori. Atrophic gastritis is an important clinical feature of high-risk antibiotic resistance in H. pylori-infected patients. Patients with atrophic gastritis have higher risk of resistant strains infection. In this study, our data provide the association between antibiotic resistance of H. pylori and gastritis pattern, which indicate the higher risk of resistant strain infection if the patients with atrophic gastritis, PPI history and older age. [ABSTRACT FROM AUTHOR]

The Fluid Physics Research Rack (FPR) is a research platform employed on-board the Chinese Space Station for conducting microgravity fluid physics experiments. The research platform includes the Microgravity Active Vibration Isolation System (MAVIS) for isolating the FPR from disturbances arising from the space station itself. The MAVIS is a structural platform consisting of a stator and floater that are monitored and controlled with non-contact electromagnetic actuators, high-precision accelerometers, and displacement transducers. The stator is fixed to the FPR, while the floater serves as a vibration isolation platform supporting payloads, and is connected with the stator only with umbilicals that mainly comprise power and data cables. The controller was designed with a correction for the umbilical stiffness to minimize the effect of the umbilicals on the vibration isolation performance of the MAVIS. In-orbit test results of the FPR demonstrate that the MAVIS was able to achieve a microgravity level of 1–30 μg0 (where g0 = 9.80665 m ∙ s−2) in the frequency range of 0.01–125 Hz under the microgravity mode, and disturbances with a frequency greater than 2 Hz are attenuated by more than 10-fold. Under the vibration excitation mode, the MAVIS generated a minimum vibration acceleration of 0.4091 μg0 at a frequency of 0.00995 Hz and a maximum acceleration of 6253 μg0 at a frequency of 9.999 Hz. Therefore, the MAVIS provides a highly stable environment for conducting microgravity experiments, and promotes the development of microgravity fluid physics. [ABSTRACT FROM AUTHOR]

Background: Endoscopic submucosal dissection (ESD) has been a valuable treatment of choice for rectal neuroendocrine tumors (NETs). However, the vertical margin may remain positive after ESD because the neuroendocrine tumors develop in a submucosal tumor (SMT)-like way. Endoscopic submucosal dissection with myectomy (ESD-ME), a new method for rectal NETs, may overcome this problem.Methods: From August 2013 to August 2020, the medical records of 69 patients (72 rectal neuroendocrine tumors) who received endoscopic submucosal dissection (ESD) or endoscopic submucosal dissection with myectomy (ESD-ME) for rectal NETs were investigated retrospectively. The characteristics of the patients and tumors, the rate of complete resection, and the rate of complications were analyzed retrospectively.Results: The ESD-ME group contained 27 patients (12 males, 15 females; age range 29-72 years) and the ESD group contained 42 patients (21 males, 21 females; age range 29-71 years). Both groups had similar mean rectal neuroendocrine tumor diameters (ESD-ME 6.1 ± 1.8 mm, ESD 6.7 ± 2.6 mm; P = 0.219). The procedure time was not different significantly between groups (ESD-ME 21.1 ± 6.3, ESD 19.3 ± 3.1; P = 0.115). The endoscopic complete resection rate did not differ significantly between the ESD-ME and ESD groups (100% for each). The histological complete resection rate was 100% (27 of 27) in the ESD-ME group and 81.0% (34 of 42) in the ESD group (P = 0.043). Delayed bleeding occurred in 1 ESD-ME patient (3.7%) and in 2 ESD patients (4.8%) (P = 1.000). Perforation occurred in 1 ESD-ME patient (3.7%) and the patient was successfully managed by conservative measure, and there was no perforation after ESD (P = 0.391).Conclusions: When compared with ESD, ESD-ME resulted in a higher histological complete resection rate, had a similar complication rate, and took similar time to perform. ESD-ME can be considered an effective and safe resection method for rectal NETs < 16 mm in diameter without metastasis. [ABSTRACT FROM AUTHOR]

Background: The distorted anatomy in patients with obstruction renders colon stent placement difficult. Here, we propose two novel techniques for stent implantation. Methods: Patients in whom there was difficulty placing the guidewire with the normal method were retrospectively included in our study. All of the patients underwent the technique of combining a slim gastroscope with a normal colonoscope. We assessed the technical success, clinical success, and adverse events associated with self-expanding metal stent placement. Results: From June 2018 to June 2020, 30.5% of patients with difficult catheterization were included in this study. Finally, stents in 17 of 18 patients (3 rectum, 13 sigmoid colon, 1 descending colon, and 1 hepatic flexure) (94.4%) were placed successfully, assisted by a slim gastroscope with or without radiography, and the obstruction was relieved. Only one remaining patient experienced failure. No intraoperative or 30-day postoperative morbidity or mortality was observed. Conclusion: The present study showed that the stent implantation technique assisted by a slim gastroscope combined with a normal colonoscope was a relatively safe and effective method for abolishing difficult intestinal stenosis. More studies are needed to compare the advantages and disadvantages of this technique with normal endoscopic implantation. [ABSTRACT FROM AUTHOR]

The Mufushan-Jiaoshan fault (MJF) is a hidden active fault located on the north side of the Ningzhen Mountain Range and developed along the Yangtze River in Zhenjiang area, China. In this paper, the structure of MJF is detected and studied using group-velocity ambient noise tomography. In the study area (18 km × 25 km), 47 short-period seismic stations were deployed with the average station spacing of about 3 km and 24 days (from 27 February to 22 March 2019) of continuous ambient-noise recordings were collected. And 510 group velocity dispersion curves in the period band 0.5–5 s were extracted using the vertical component data. And then the three-dimensional shear-wave velocity structure was inverted using group dispersion data by the direct surface-wave tomographic method. Our results are consistent with the geological background of the study area, showing that in the depth range of 0.6–1.5 km, the north side of MJF presents a relatively high velocity, and the south side presents a distribution pattern of high and low velocity. While in the depth range of 1.5–2.0 km, the shear-wave velocity (Vs) model is relatively simple with relatively low velocity on the north side and relatively high velocity on the south side. And the gradient zone of Vs may be the location of the main fracture surface of MJF. The good correspondence between the Vs model and the fault structure indicates that the ambient noise tomography method can be used as an effective method for detecting hidden faults in urban environments. [ABSTRACT FROM AUTHOR]

Long intergenic non-protein-coding RNA 152 (LINC00152) is one of the long noncoding RNAs (lncRNAs) abnormally expressed in gastric cancer tissues. However, its value in the diagnosis of gastric cancer is unclear. The aim of this study is to evaluate the clinical significance of plasma LINC00152 as a biomarker in the screening of gastric cancer and to explore the possible mechanism underling its stable existence in blood. We analyzed the levels of plasma LINC00152 in patients with gastric cancer and gastric epithelial dysplasia and healthy controls using quantitative reverse transcription polymerase chain reaction and then confirmed by sequencing. We also compared its levels in paired preoperative and postoperative plasma samples. In addition, we compared the levels of LINC00152 in plasma and in exosomes, which were extracted from the same plasma and confirmed by transmission electron microscopy. The levels of plasma LINC00152 were significantly elevated in gastric cancer patients compared with healthy controls. The sensitivity and specificity of plasma LINC00152 in the diagnosis of gastric cancer were 48.1 and 85.2 %, respectively. There were no significant differences of LINC00152 levels between gastric epithelial dysplasia patients and healthy controls. LINC00152 levels in preoperative plasma samples were lower than those in postoperative ones. There were also no differences between LINC00152 levels in plasma and in exosomes. All these results suggested that LINC00152 can be detected in plasma, and one of the possible mechanisms of its stable existence in blood was protected by exosomes. It has the possibility to be applied in gastric cancer diagnosis as a novel blood-based biomarker. [ABSTRACT FROM AUTHOR]

MicroRNA-421 (miR-421) plays crucial roles during carcinogenesis and is a potential tumor marker in the diagnosis of several types of cancers. However, whether miR-421 in gastric juice, which is specific for gastric tissue, can be used as a biomarker for gastric cancer screening is unclear. In the present study, real-time quantitative reverse transcription-polymerase chain reaction was used to analyze miR-421 levels in gastric juice from patients with gastric cancer or benign gastric disease, or normal. A receiver operating characteristic (ROC) curve was constructed to evaluate the diagnostic values. The results showed that gastric juice levels of miR-421 in patients with gastric cancer were significantly different from those in benign gastric diseases ( P < 0.001). The area under the ROC curve of miR-421 was up to 0.767 (95 % CI = 0.684-0.850). The levels of miR-421 in gastric juice from gastric patients were not significantly associated with the main clinicopathological factors such as tumor size, Lauren's classification, and Borrmann's classification. For the detection of early gastric cancer, the use of gastric juice miR-421showed a remarkable improvement compared with the use of serum carcinoembryonic antigen alone. These results indicated that gastric juice miRNAs such as miR-421 are useful biomarkers for screening gastric cancer. [ABSTRACT FROM AUTHOR]