Transition in electronic and magnetic properties of transition metal embedded semimetallic B-graphyne.

Spintronics is extremely important in the future development of information technology. Notably, two-dimensional carbon materials with atomically thick and p-electron systems have great potential for application in ultrathin spintronic devices. B-graphyne (B-GY) is a recently proposed two-dimensional carbon allotrope with double Dirac cones. It is a promising nanomaterial for high-speed spintronic devices due to its ultra-high Fermi velocity and thermodynamic stability. We tune the electronic and magnetic properties of B-GY by doping 3d transition metals (TM) (Cr, Mn, Fe, Co, Ni) based on first-principles calculations. After doping, TM forms strong covalent bonds (Fe, Co, Ni) and ionic bonds (Cr, Mn) with adjacent C atoms. The system of TM-doped B-GY (TM@B-GY) is transformed from a semimetal for B-GY to a metal (Cr, Mn, Fe, Co), but Ni@B-GY is still semimetal. Among them, Co@B-GY is approximately a half-metal. Moreover, TM (except Ni) can induce the magnetism of B-GY to undergo spin splitting. The TM d-orbitals are strongly coupled to the C p-orbitals, which play an important role in inducing magnetism. The results show that the tunable electronic and magnetic properties of TM@B-GY are promising as a high-speed spintronic device. Our research helps advance the study of semimetallic carbon allotropes in the field of spintronics.

Development and validation of an online calculator to predict the pathological nature of colorectal tumors.

BACKGROUND: No single endoscopic feature can reliably predict the pathological nature of colorectal tumors (CRTs). AIM: To establish and validate a simple online calculator to predict the pathological nature of CRTs based on white-light endoscopy. METHODS: This was a single-center study. During the identification stage, 530 consecutive patients with CRTs were enrolled from January 2015 to December 2021 as the derivation group. Logistic regression analysis was performed. A novel online calculator to predict the pathological nature of CRTs based on white-light images was established and verified internally. During the validation stage, two series of 110 images obtained using white-light endoscopy were distributed to 10 endoscopists [five highly experienced endoscopists and five less experienced endoscopists (LEEs)] for external validation before and after systematic training. RESULTS: A total of 750 patients were included, with an average age of 63.6 ± 10.4 years. Early colorectal cancer (ECRC) was detected in 351 (46.8%) patients. Tumor size, left semicolon site, rectal site, acanthosis, depression and an uneven surface were independent risk factors for ECRC. The C-index of the ECRC calculator prediction model was 0.906 (P = 0.225, Hosmer-Lemeshow test). For the LEEs, significant improvement was made in the sensitivity, specificity and accuracy (57.6% vs 75.5%; 72.3% vs 82.4%; 64.2% vs 80.2%; P < 0.05), respectively, after training with the ECRC online calculator prediction model. CONCLUSION: A novel online calculator including tumor size, location, acanthosis, depression, and uneven surface can accurately predict the pathological nature of ECRC.

Endoscopic classification and pathological features of primary intestinal lymphangiectasia.

BACKGROUND: The appearance of the intestinal mucosa during endoscopy varies among patients with primary intestinal lymphangiectasia (PIL). AIM: To classify the endoscopic features of the intestinal mucosa in PIL under endoscopy, combine the patients' imaging and pathological characteristics of the patients, and explain their causes. METHODS: We retrospectively analyzed the endoscopic images of 123 patients with PIL who were treated at the hospital between January 1, 2007 and December 31, 2018. We compared and analyzed all endoscopic images, classified them into four types according to the endoscopic features of the intestinal mucosa, and analyzed the post-lymphographic computed tomography (PLCT) and pathological characteristics of each type. RESULTS: According to the endoscopic features of PIL in 123 patients observed during endoscopy, they were classified into four types: nodular-type, granular-type, vesicular-type, and edematous-type. PLCT showed diffuse thickening of the small intestinal wall, and no contrast agent was seen in the small intestinal wall and mesentery in the patients with nodular and granular types. Contrast agent was scattered in the small intestinal wall and mesentery in the patients with vesicular and edematous types. Analysis of the small intestinal mucosal pathology revealed that nodular-type and granular-type lymphangiectasia involved the small intestine mucosa in four layers, whereas ectasia of the vesicular- and edematous-type lymphatic vessels largely involved the lamina propria mucosae, submucosae, and muscular layers. CONCLUSION: Endoscopic classification, combined with the patients' clinical manifestations and pathological examination results, is significant and very useful to clinicians when scoping patients with suspected PIL.

A novel dextranase gene from the marine bacterium Bacillus aquimaris S5 and its expression and characteristics.

Dextranase specifically hydrolyzes dextran and is used to produce functional isomalto-saccharide prebiotics. Moreover, dextranase is used as an additive in mouthwash to remove dental plaque. We cloned and expressed the dextranase gene of the marine bacterium Bacillus aquimaris S5. The length of the BaDex gene was 1788 bp, encoding 573 amino acids. Using bioinformatics to predict and analyze the amino acid sequence of BaDex, we found the isoelectric point and instability coefficient to be 4.55 and 29.22, respectively. The average hydrophilicity (GRAVY) was -0.662. The secondary structure of BaDex consisted of 145 alpha helices, accounting for 25.31% of the protein; 126 extended strands, accounting for 21.99%; and 282 random coils, accounting for 49.21%. The 3D structure of the BaDex protein was predicted and simulated using SWISS-MODEL, and BaDex was classified as a Glycoside Hydrolase Family 66 protein. The optimal temperature and pH for BaDex activity were 40°C and 6.0, respectively. The hydrolysates had excellent antioxidant activity, and 8 U/mL of BaDex could remove 80% of dental plaque in MBRC experiment. This recombinant protein thus has great promise for applications in the food and pharmaceutical industries.

Immobilization of Dextranase on Nano-Hydroxyapatite as a Recyclable Catalyst.

The immobilization technology provides a potential pathway for enzyme recycling. Here, we evaluated the potential of using dextranase immobilized onto hydroxyapatite nanoparticles as a promising inorganic material. The optimal immobilization temperature, reaction time, and pH were determined to be 25 °C, 120 min, and pH 5, respectively. Dextranase could be loaded at 359.7 U/g. The immobilized dextranase was characterized by field emission gun-scanning electron microscope (FEG-SEM), X-ray diffraction (XRD), and Fourier-transformed infrared spectroscopy (FT-IR). The hydrolysis capacity of the immobilized enzyme was maintained at 71% at the 30th time of use. According to the constant temperature acceleration experiment, it was estimated that the immobilized dextranase could be stored for 99 days at 20 °C, indicating that the immobilized enzyme had good storage properties. Sodium chloride and sodium acetic did not desorb the immobilized dextranase. In contrast, dextranase was desorbed by sodium fluoride and sodium citrate. The hydrolysates were 79% oligosaccharides. The immobilized dextranase could significantly and thoroughly remove the dental plaque biofilm. Thus, immobilized dextranase has broad potential application in diverse fields in the future.

Characterization and mechanism of the effects of Mg-Fe layered double hydroxide nanoparticles on a marine bacterium: new insights from genomic and transcriptional analyses.

BACKGROUND: Layered double hydroxides (LDHs) have received widespread attention for their potential applications in catalysis, polymer nanocomposites, pharmaceuticals, and sensors. Here, the mechanism underlying the physiological effects of Mg-Fe layered double hydroxide nanoparticles on the marine bacterial species Arthrobacter oxidans KQ11 was investigated. RESULTS: Increased yields of marine dextranase (Aodex) were obtained by exposing A. oxidans KQ11 to Mg-Fe layered double hydroxide nanoparticles (Mg-Fe-LDH NPs). Furthermore, the potential effects of Mg-Fe-LDH NPs on bacterial growth and Aodex production were preliminarily investigated. A. oxidans KQ11 growth was not affected by exposure to the Mg-Fe-LDH NPs. In contrast, a U-shaped trend of Aodex production was observed after exposure to NPs at a concentration of 10 µg/L-100 mg/L, which was due to competition between Mg-Fe-LDH NP adsorption on Aodex and the promotion of Aodex expression by the NPs. The mechanism underling the effects of Mg-Fe-LDH NPs on A. oxidans KQ11 was investigated using a combination of physiological characterization, genomics, and transcriptomics. Exposure to 100 mg/L of Mg-Fe-LDH NPs led to NP adsorption onto Aodex, increased expression of Aodex, and generation of a new Shine-Dalgarno sequence (GGGAG) and sRNAs that both influenced the expression of Aodex. Moreover, the expressions of transcripts related to ferric iron metabolic functions were significantly influenced by treatment. CONCLUSIONS: These results provide valuable information for further investigation of the A. oxidans KQ11 response to Mg-Fe-LDH NPs and will aid in achieving improved marine dextranase production, and even improve such activities in other marine microorganisms.

[Vegetation spatial and temporal dynamic characteristics based on NDVI time series trajectories in grassland opencast coal mining]. / 基于NDVI时间序列轨迹的草原露天矿区植被时空动态特征.

The spatiotemporal dynamic patterns of vegetation in mining area are still unclear. This study utilized time series trajectory segmentation algorithm to fit Landsat NDVI time series which generated from fusion images at the most prosperous period of growth based on ESTARFM algorithm. Combining with the shape features of the fitted trajectory, this paper extracted five vegetation dynamic patterns including pre-disturbance type, continuous disturbance type, stabilization after disturbance type, stabilization between disturbance and recovery type, and recovery after disturbance type. The result indicated that recovery after disturbance type was the dominant vegetation change pattern among the five types of vegetation dynamic pattern, which accounted for 55.2% of the total number of pixels. The follows were stabilization after disturbance type and continuous disturbance type, accounting for 25.6% and 11.0%, respectively. The pre-disturbance type and stabilization between disturbance and recovery type accounted for 3.5% and 4.7%, respectively. Vegetation disturbance mainly occurred from 2004 to 2009 in Shengli mining area. The onset time of stable state was 2008 and the spatial locations mainlydistributed in open-pit stope and waste dump. The reco-very state mainly started since the year of 2008 and 2010, while the areas were small and mainly distributed at the periphery of open-pit stope and waste dump. Duration of disturbance was mainly 1 year. The duration of stable period usually sustained 7 years. The duration of recovery state of the type of stabilization between disturbances continued 2 to 5 years, while the type of recovery after disturbance often sustained 8 years.

A Retrospective Research of the Characteristic of Hypertriglyceridemic Pancreatitis in Beijing, China.

Aim. To investigate the characteristic of hypertriglyceridemic- (HTG-) induced pancreatitis (HTG pancreatitis). Methods. We reviewed 126 cases of HTG pancreatitis and 168 cases of biliary pancreatitis as control. Results. The HTG group mean age was younger than biliary group. The number of females was a little higher than males in both groups. There were 18 cases that were recurrent in HTG group and 11 in billiary group. The mean hospitalization times were 13.7 ± 2.6 and 11.2 ± 2.3 days in two groups. Six patients received apheresis in HTG group. The proportion of severe AP was 31.0% and 26.2%, mortality 1.6% and 1.2%, comorbidity of diabetes mellitus (DM) 20.6% and 6.5% in two groups. The number of complications of gastrointestinal (GI) bleeding, sepsis, and multiple organ dysfunction syndrome (MODS) in HTG group and biliary group was 1, 1, and 2 versus 4, 12, and 4. Conclusions. The proportion of recurrent and severe AP and comorbidity of DM of HTG group was higher than billiary group. The proportion of the complications of GI bleeding, sepsis, and MODS of HTG group was less than biliary group. Apheresis could effectively reduce serum TG levels soon. There was no significant difference of the mortality between two groups.

PVDF-Nafion nanomembranes coated microneedles for in vivo transcutaneous implantable glucose sensing.

We demonstrate that microporous PVDF membranes sandwiched between multiple layers of nanomaterials can be used for continuous monitoring of glucose level in vivo. This is achieved by coating needle electrodes with Polyaniline nanofiber, Platinum nanoparticles, glucose oxidase enzyme and porous layers, successfully fabricated with layer-by-layer deposition. Nanoparticles incorporated into conductive Polyaniline nanofibers resulted in high surface to volume ratio and electrocatalytic activity for glucose enzyme. A composite coating membrane of porous PVDF and nano-sphere Nafion limited the glucose transportation and increased the lifetime of in vivo measurements. The glucose biosensor exhibited a sub-microamperometric output current, fast response time of less than 30s and a sensitivity of 0.23 µA/mM. The linear sensing range in terms of glucose concentration was from 0 to 20mM. Implantable experiments using mice models showed excellent response to the variation of blood glucose concentration while maintaining biocompatibility with the surrounding tissues. The sensitivity was shown to remain within 10% close to initial sensitivity within the 7 days of continuous monitoring, and maintain at 70% of the initial sensitivity within 21 days.

Friction phenomena in the overdamped three-layer model.

An overdamped three-layer model consisting of two harmonic chains of interacting particles, representing the upper and the middle layers, which move over the substrate potential, is studied in the present paper. A dc+ac force is applied only on the upper harmonic chain, and dynamics of both layers are investigated. The results show that the dynamical mode locking and Shapiro steps appear not only in the upper layer but also in the middle one. It is noted that the motion of particles in the upper layer corresponds to the standard Frenkel-Kontorova model. The dependence of the Shapiro steps of the middle layer on the system parameters are determined. It is shown that the height of the first Shapiro step of the upper layer is unrelated to the interaction parameters of the particles of both the upper and the middle layers, while the height of the first Shapiro step of the middle layer depend only on the interaction parameters of the particles of the middle layers. Two critical forces which transfer from locked state to the sliding one of both the upper and the middle layers are also studied. They depend on the amplitude and the frequency of the external ac driving force.

The mechanisms of 5-FU-PLA-O-CMC-NPS-mediated inhibition of the proliferation of colorectal cancer cell line SW480.

We aimed to investigate how 5-FU-PLA-O-CMC-NP (5-FPOCN) inhibits the proliferation of the SW480 colon cancer cell line. Following the treatment of cell line SW480 with 0.1, 1, 10 or 100 µg/ml 5-FPOCN or 5-fluorouracil (fluorouracil, 5-Fu) for 0, 24, 48, or 72, the rate of cell was tested by the tetrazolium assay (MTT). After the SW480 cells were treated with 5-FPOCN or 5-FU for 72 h, the growth rate and apoptosis were detected. After the SW480 cells were treated with 5-FPOCN or 5-FU for 24, 48, 72, or 120, flow cytometry (FCM) was used to determine the cell cycle distribution. The changes in the expression of P21, CyclinD1 and Rb were detected by Western blotting and real-time PCR. We found that different doses of 5-FPOCN can significantly inhibit the growth rate of SW480 cells, and this effect is dose and time dependent. However, there is no significant difference from 72 to 120 h (P>0.05). After 5-FPOCN treatment for 72 h, there is a negative correlation between the concentration of 5-FPOCN and the activity of SW480 cells and a positive correlation between the concentration of 5-FPOCN and SW480 cell apoptosis. G1 phase was significantly increased, and S phase was significantly decreased in 5-FPOCN-treated SW480 cells at 72 h compared to the control group (P<0.05); there was a positive correlation between the concentration of 5-FPOCN and the above changes. It was suggested that 5-FPOCN can delay G1/S phase and that this is a dose-dependent effect. The expression of P21 protein and messenger RNA (mRNA) and Rb protein and mRNA was significantly increased in 5-FPOCN-treated SW480 cells at 72 h compared to the control group, and this was a dose- and time-dependent effect. CyclinD1 protein and mRNA expression was reduced as the dose increased, and its expression was negatively associated with the increased expression of P21. We concluded that 5-FPOCN can significantly inhibit the growth of colon cancer SW480 cells. 5-FPOCN increased P21 expression and decreased cyclin family and pRb expression to promote cell cycle delay and apoptosis.

[Expression of monocyte chemotactic protein-1 and its receptor in sudden coronary death].

OBJECTIVE: To investigate the expression of monocyte chemotactic protein-1 (MCP-1) and its receptor CC chemokine receptor-2 (CCR-2) in coronary atherosclerosis plaques between sidden coronary death (SCD) and non-SCD. Methods The expression levels of MCP-1 and CCR-2 in SCD group, coronary atherosclerosis group (non-SCD), control group (normal coronary artery) were detected by immunohistochemistry. RESULTS: Positive rates of MCP-1 among the three groups were 78%, 47%, and 0%, respectively, with significant expressing differences between each two groups (P<0.05). Positive rates of CCR-2 among three groups were 72%, 47%, and 0%, respectively, with significant expressing differences between the SCD group and coronary atherosclerosis group as well as between the SCD group and control group (P<0.05), but with no significant expressing difference between coronary atherosclerosis group and control group (P>0.05). CONCLUSION: Overexpression of MCP-1 and CCR-2 in coronary atherosclerotic plaques is closely correlated with SCD.

Appendiceal mucocele: A diagnostic dilemma in differentiating malignant from benign lesions with CT.

OBJECTIVE: The purpose of this study was to assess the feasibility of using CT to differentiate malignant from benign lesions in patients with pathologically confirmed appendiceal mucoceles. MATERIALS AND METHODS: CT scans of 18 consecutively registered patients (11 men, seven women; age range, 21-78 years) with pathologically confirmed appendiceal mucocele were reviewed retrospectively. Patients were classified into three groups according to pathologic results: nonneoplastic mucocele (n = 3), mucinous cystadenoma (n = 10), and mucinous cystadenocarcinoma (n = 5). The nonneoplastic and mucinous cystadenoma groups were formed into a benign group, and the mucinous cystadenocarcinoma constituted the malignant group. Two experienced radiologists working in consensus assessed the shape, short diameter, density, contour, and wall thickness of the masses. The presence of calcifications, internal septations, soft-tissue thickening, periappendiceal fat stranding, intraperitoneal free fluid and pseudomyxoma peritonei were also evaluated. The CT results were compared for malignant and benign appendiceal mucoceles. RESULTS: CT showed statistically significant differences in wall irregularity and soft-tissue thickening between malignant and benign cases (p < 0.05). Short diameter of mucoceles, attenuation of intraluminal contents, maximal wall thickness, calcifications, internal septations, periappendiceal fat stranding, intraperitoneal free fluid, and pseudomyxoma peritonei in the lesions did not differ significantly between the benign and malignant groups (p > 0.05). CONCLUSION: Differentiating malignant from benign mucoceles can be difficult with CT. Irregular walls and soft-tissue thickening are features most likely to be associated with malignancy.

Glycosylation of the polypropylene membrane surface via thiol-yne click chemistry for lectin adsorption.

Glycosylated membrane, as one of the most important affinity membranes, permits affinity separation/purification of proteins based on carbohydrate-protein interactions. It is an important scientific issue to screen facile method for fabricating the glycosylated membrane surface with high glycosyl density. Such a surface can be fabricated by the direct covalent immobilization of carbohydrate ligands on the surfaces of microporous polypropylene membrane (MPPM). First, alkyne-functionalized membrane surface was fabricated by plasma pretreatment combined with UV-induced graft polymerization of 3-(trimethylsilyl) propargyl methacrylate. Then, the glycosylated membrane surface was directly fabricated with the thiol-yne click reaction to ensure rapid process, improved efficiency, and high glycosyl density. Chemical and physical properties of the membrane surface were characterized by ATR/FT-IR, XPS, FESEM and water contact angle measurement. Static lectin adsorption indicates that the glycosylated membrane can specifically adsorb lectin concanavalin A (Con A) other than peanut agglutinin (PNA). Break through curves from dynamic Con A adsorption show the membrane has unique properties such as strong specificity, high adsorption capacity, and reversible binding capability. We suggest that the prepared glycosylated membrane is of great potentials in affinity membrane chromatography for rapid and high-resolution separation/purification of lectins.

Ratchet effect and amplitude dependence of phase locking in a two-dimensional Frenkel-Kontorova model.

We demonstrate the ratchet and phase locking effects in a two-dimensional overdamped Frenkel-Kontorova model with a square symmetric periodic substrate when both a longitudinal dc drive and a circular ac drive are applied. Besides the harmonic steps, the large half integer steps can also clearly be seen in the longitudinal (x) direction. These half integer steps are directly correlated to the appearance of positive and negative ratchet effects in the transverse (y) direction due to the symmetry breaking in the combination of the dc and ac drives. The angle between the net displacement and the longitudinal direction is analytically obtained in a single period of the ac drive. In the examination of the amplitude dependence of the ac drive, the maxima decrease monotonically with the amplitude, while the anomalies occur for the critical depinning force and the harmonic steps due to the spatial symmetry breaking of orbits in the presence of the ac drive.

[Progress in the application of conducting polymer in glucose biosensor].

Conducting polymers have stable long-chain structure and good electrical conductivity. They have been used in various types of biosensors because of their excellent characteristics of the immobilization and electrical signal transmission. In recent years, researchers mainly study on improving its micro-nano structures and its signal conductivity to enhance its effect on the enzyme immobilization and signal conductive properties. This paper reviews firstly the application of conducting polymer on enzyme-immobilized glucose biosensor and the new technologies and methods in this field. This paper also points out the future application of conducting polymers in enzyme immobilization and biosensor preparation areas.

[Advances in sensor node and wireless communication technology of body sensor network].

With the development of the wireless communication technology, implantable biosensor technology, and embedded system technology, Body Sensor Network (BSN) as one branch of wireless sensor networks and important part of the Internet of things has caught more attention of researchers and enterprises. This paper offers the basic concept of the BSN and analyses the related research. We focus on sensor node and wireless communication technology from perspectives of technology challenges, research advance and development trend in the paper. Besides, we also present a relative overview of domestic and overseas projects for the BSN.

[Efficacies of lactulose plus live combined Bacillus subtilis and Enterococcus faecium capsules in the treatment of functional constipation: a multicenter, randomized, double blind, controlled trial].

OBJECTIVE: To explore the efficacies of live combined Bacillus subtilis (B. subtilis) and Enterococcus faecium (E. faecium) capsules plus lactulose in the treatment of functional constipation. METHODS: A total of 216 patients fulfilling the diagnostic criteria of functional constipation (slow transit pattern) were randomly enrolled from 9 participating hospitals and allocated into treatment group and control group. The patients of treatment group received lactulose plus live combined B. subtilis and E. faecium capsules for 14 days and only took the latter during the following 14 days. The patients of control group received lactulose plus placebo for 2 weeks and then only took placebo continually for the following 2 weeks. RESULTS: A total of 216 patients were analyzed (treatment group n = 104, control group n = 112). The effective rates of 7-day treatment were 88.46% (n = 92) and 84.82% (n = 95) for treatment and control groups respectively. And those of 28-day treatment were 87.50% (n = 91) and 81.25% (n = 91)respectively. And the inter-group differences were not statistically significant (all P > 0.05). Fecal form, frequency, difficulty, urgency, distension, abdominal pain and expelling rates of barium enema were not statistically significant (all P > 0.05). Comparing the effective rates of 28-day with that of 14-day, differences were not statistically significant in A group (S = 0.5, P = 0.4795), but in B group the effective rates of 28-day were lower than that of 14-day statistically(S = 11, P = 0.0009). CONCLUSION: The regiment of live combined B. subtilis and E. faecium capsules plus lactulose offers better efficacies in the treatment of functional constipation.

Existence and stability of the resonant phenomena in the dc- and ac-driven overdamped Frenkel-Kontorova model with the incommensurate structure.

Dynamical mode-locking phenomena in the incommensurate structures of the dc- and ac-driven overdamped Frenkel-Kontorova model are studied by molecular-dynamics simulations. The obtained results have shown that Shapiro steps exhibit significantly different amplitude and frequency dependence from the one observed in the commensurate structures. Due to the incommensurability of the system the special symmetry of the motion of particles is broken, and in the amplitude dependence of Shapiro steps, this will result in the appearance of anomalies and deviation from the well-known Bessel-like behavior. In the frequency or period dependence, oscillations have been observed in the high-amplitude limit; however, they exhibit strong anomalies compared with those in the commensurate structures. The oscillatory behavior and the anomalies have been also be revealed in the (F(ac),F) and the (ν(0),F) phase diagrams where several phases are defined.