Risk factors for delayed colorectal postpolypectomy bleeding: a meta-analysis.

BACKGROUND: To systematically analyze risk factors for delayed postpolypectomy bleeding (DPPB) in colorectum. METHODS: We searched seven large databases from inception to July 2022 to identify studies that investigated risk factors for DPPB. The effect sizes were expressed by relative risk (RR) and 95% confidence interval (95% CI). The heterogeneity was analyzed by calculating I2 values and performing sensitivity analyses. RESULTS: A total of 15 articles involving 24,074 subjects were included in the study. The incidence of DPPB was found to be 0.02% (95% CI, 0.01-0.03), with an I2 value of 98%. Our analysis revealed that male sex (RR = 1.64), history of hypertension (RR = 1.54), anticoagulation (RR = 4.04), polyp size (RR = 1.19), polyp size ≥ 10 mm (RR = 2.43), polyp size > 10 mm (RR = 3.83), polyps located in the right semicolon (RR = 2.48) and endoscopic mucosal resection (RR = 2.99) were risk factors for DPPB. CONCLUSIONS: Male sex, hypertension, anticoagulation, polyp size, polyp size ≥ 10 mm, polyps located in the right semicolon, and endoscopic mucosal resection were the risk factors for DPPB. Based on our findings, we recommend that endoscopists should fully consider and implement effective intervention measures to minimize the risk of DPPB.

Breathable and wearable graphene/waterborne polyurethane coated regenerated polyethylene terephthalate fabrics for motion sensing and thermal therapy.

The functional utilization of recycled polymers has emerged as a current prominent and timely subject. Flexible wearable devices with high sensitivity to conductivity have garnered significant attention in the fields of human healthcare monitoring and personal heat management. One significant obstacle that needs to be addressed is the simultaneous maintenance of both sensing functionality and durability in composite fabrics. In this paper, a collection of durable, breathable, and flexible smart fabric was produced using the scratch coating method. The fabrics were created by utilizing a regenerated polyethylene terephthalate fabric as a base material, incorporating graphene microsheets (G) as a conductive agent, and applying a waterborne polyurethane layer as a surface protective coating. Furthermore, an investigation was conducted to assess their sensing performance and electrothermal performance. The composite fabric exhibits significant advantages in terms of high conductivity (592 S/m), wide strain range, high sensitivity (Gauge factor = 6.04) and fantabulous dynamic stability (2000 cycles) at a mass ratio of Graphene/WPU loading of 8:2. These sensors were successfully utilized to monitor various degrees of real-time human body movements, ranging from significant deformation bending of elbows to slight deformation swallowing. Furthermore, the sensors also exhibit a significant electric heating effect. Specifically, when a voltage of 10 V is applied, the sensors can reach a steady state temperature of 53.3 °C within a mere 30 s. This discovery holds potential for the development of wearable heaters that can be used for on-demand thermal therapy, functional protective clothing, and medical electric heating wearables.

Synergistic enhancement of modified sericite on rheological and foaming properties of poly (lactic acid).

Due to low melt strength and slow crystallization rate, poly (lactic acid) (PLA) foam materials are still not satisfactory. In order to improve the foaming performance of PLA, sericite (GA) was selected as the filler and modified by 3-Aminopropyltriethoxysilane (KH-550). Through melt blending with PLA, azodicarbonamide (ADC) foaming agent was selected for molding foaming, and PLA/GA composite foam was prepared. The addition of GA not only acts as a nucleating agent to improve the crystallization performance of the blend, but also improves its complex viscosity and storage modulus, and enhances its melt strength, so that the compressive strength and impact strength of the prepared composite foam are increased by 265.5 % and 224.0 %, respectively. Compared with PE foam, PLA/GA composite foam showed excellent thermal insulation performance through thermal infrared imaging test. Based on its mechanical and thermal insulation properties, this sample provides new materials for the field of wall insulation and foam packaging. This study provides an effective way to improve the melt strength and workability of PLA.

Understanding the hydrolysis mechanism on segments and aggregate structures: Corrosion-tailored poly (lactic acid) deriving copolymers with δ-valerolactone.

Poly (L-lactic acid) (PLLA) based copolymers modified with δ-valerolactone (DVL) through random copolymerization (PVLA-R) and block copolymerization (PVLA-B) with various DVL content were prepared to investigate their degradation regulation and mechanism. Chemical structure, thermal properties, hydrophilicity, crystallization as well as the crystal defects of the obtained copolymers were respectively confirmed. Degradation regulation of both PVLA-R and PVLA-B, such molecular weight and pH value changes of PLLA based copolymers were investigated via vitro degradation method. In order to further explore the degradation principle of the two copolymers, their degradation residues at different stages were systematically studied. The addition and increasing content of DVL disturbs the regularity of original PLLA molecular structure, resulting in accelerating degradation of copolymers. Compared with amorphous region, the crystalline region of both two copolymers has better corrosion resistance, which could be confirmed by increased melting point and crystallinity of both PVLA-R and PVLA-B degradation residues. PVLA-B copolymers show relatively superior degradation resistance mainly due to their higher molecular weight, crystallinity and hydrophobic index than PVLA-R copolymers.

Clinical Observation of the Effect of Nasal Breathing on Nonanalgesic and Sedative Gastroscopy.

This study aimed to investigate the safety, tolerance, and comfort of the subjects in gastroscopy by observing and comparing the effect of gastroscopy under two different breathing modes: nasal breathing and nasal inspiration and oral expiration. A total of 60 subjects who underwent routine gastroscopy in the hospital from January 2021 to June 2021 were selected as the research subjects. According to the willingness of the subjects, they were divided into a nasal breathing group and a nasal inspiration and oral expiration group. The differences in vital signs, adverse reactions, and visual analog scale (VAS) scores were compared between the two groups. There were no significant differences in mean arterial pressure, heart rate, and blood oxygen saturation between the two groups before, during, and after the examination (P > 0.05). The nasal breathing group had fewer adverse reactions such as nausea, cough, belching, and restlessness than the nasal inspiration and oral expiration group, and the difference was statistically significant (P < 0.01). VAS score of the nasal breathing group was lower than that of the nasal inspiration and oral expiration group, and the difference was statistically significant (P < 0.01). Subjects are more tolerant to nasal breathing mode, which causes fewer adverse reactions, less pain, and more comfort and is more worthy to be popularized in primary hospitals.

EZH2 identifies the precursors of human natural killer cells with trained immunity.

OBJECTIVE: Trained immunity of natural killer (NK) cells has shown great potential in the treatment of cancers by eliciting enhanced effector responses to restimulation by cytokines or cancer cells for long time periods after preactivation. However, the human NK cells responsible for the generation and maintenance of trained immunity are largely unknown. We hypothesized that heterogeneous human NK cells would respond differentially to stimulation with a combination of IL-12, IL-15, and IL-18, and that an NK cell subset might exist that is mainly responsible for the induction of trained immunity. On the basis of our hypothesis, we aimed to identify the subset from which cytokine-trained human NK cells originate and to explore possible regulatory targets for drug intervention. METHODS: Flow cytometry assays were performed to analyze the functions of cytokine-trained NK cells and examine cell division and protein expression in NK cell subsets. Single-cell RNA sequencing (scRNA-seq) plus TotalSeq™ technology was used to track the heterogeneity of NK cells during the induction of trained immunity. RESULTS: Traditional developmental markers for peripheral NK cells were unable to identify the precursors of human NK cells with trained immunity. Therefore, we used scRNA-seq plus TotalSeq™ technology to track the heterogeneity of NK cells during the induction of trained immunity and identified a unique cluster of CD57-NKG2A+EZH2+IFNG+MKI67+IL12R+IL15R+IL18R+ NK cells. Enrichment and pseudotime trajectory analyses suggested that this cluster of NK cells contained the precursor of trained NK cells. We then used flow cytometry to further investigate the role of EZH2 in trained NK precursors and found that CD57-NKG2A+EZH2+ NK cells had faster cell cycles and an enhanced trained phenotype, and EZH2 inhibition significantly impaired the induction of trained immunity in NK cells. These results suggested that EZH2 is a unique epigenetic marker of precursors of human NK cells with trained immunity. CONCLUSIONS: Our work revealed human NK heterogeneity in the induction of trained immunity, identified the precursor subset for trained NK cells, and demonstrated the critical role of EZH2 in the induction of trained immunity in human NK cells.

Electronic modulation of novel W18O49 nanoshuttles for efficient hydrogen evolution reaction.

Research on transition metal oxides for hydrogen evolution reaction (HER) is challenging due to their poor electrical conductivity and weak hydrogen adsorption. In this paper, a class of W18O49 nanoshuttles (NSs) with highly bifurcated structure at both ends were synthesized via a hydrothermal method for highly efficient HER. By simply introducing Nb and Pt components, W18O49 can achieve optimal hydrogen adsorption through electronic modulation. The optimized NbPt/W18O49 NSs show an extremely low overpotential of 37 mV to obtain 10 mA cm-2 and an unprecedented small Tafel slope of 23 mV dec-1, superior to commercial Pt/C. The NbPt/W18O49 NSs can endure long-term stability for 18 h with negligible morphology change and performance degradation. Based on the surface valence band spectra of x-ray photoelectron spectroscopy and density functional theory calculations, the improved HER activity is closely related to the optimization of hydrogen binding energy on active sites and activation of inert O sites of W18O49. This study opens a facile avenue of electronic modulation to promote electrocatalytic performance.

Melt-spun microbial poly(3-hydroxybutyrate-co-3-hydroxyvalerate) fibers with enhanced toughness: Synergistic effect of heterogeneous nucleation, long-chain branching and drawing process.

A series of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) composite fibers were prepared via melt reactive processing where tungsten disulphide (WS2) and dicumyl peroxide (DCP) was used as heterogeneous nucleating agent and initiator, respectively. Compared with PHBV or PHBV/WS2 fiber, the resultant LCB-PHBV/WS2 fibers showed improving mechanical performance, a higher nucleation temperature and a rapid crystallization rate due to the synergistic effect between heterogeneous nucleation, long chain branched structure and draw-induced crystallization. Taking the results with a cooling rate of 20 °C/min as an example, the peak crystallization temperature of LCB-PHBV/1.0 wt%WS2 increased from 100.47 °C to 107.40 °C and the crystallization enthalpy increased from 87.95 J/g to 93.03 J/g. Moreover, two different crystalline forms, α-crystal and ß-crystal, were found in the prepared PHBV fibers, and the ß-crystal part increased with the inducement of the stretching ratio which enhanced the fiber strength, given the tensile strength and elongation at break of the LCB-PHBV/WS2 fibers up to 189.8 MPa and 46.5%, respectively.

Polybutylene succinate/cellulose nanocrystals: Role of phthalic anhydride in squeeze oriented bionanocomposites.

In order to reduce agglomerations and improve the compatibility of poly(butylenes succinate)/cellulose nanocrystals (PBS/CNC) composite, phthalic anhydride was introduced during the preparation of composite via melt blending. The composites were then suffered by squeezing treatment in a two-roll milling equipment at a given temperature. In order to investigate reaction mechanism among PBS, CNC and phthalic anhydride, PBS/CNC composites were separated and then tested via FTIR and UV-vis spectrophotometer. During reactive blending, phthalic anhydride selectively reacts with CNC, at an effective grafting ratio of 0.0196, which is confirmed by titration results. Before squeezing, the crystallinity of PBS in composites are increased but the mechanical properties of composites are weakened with increasing phthalic anhydride content, which is ascribed to the plasticizing effect of phthalic anhydride. After squeeze treatment at an extension ratio of 6, the tensile strength of PBS/PA/CNC(100/2/3) is dramatically increased from 35.2 MPa to 136 MPa. WAXD results show that PBS crystal type has little change but the crystallinity is sharply increased after orientation, which mostly contributes to the improvement of mechanical properties for PBS/CNC composites.

Construction of efficient Streptococcus zooepidemicus strains for hyaluoronic acid production based on identification of key genes involved in sucrose metabolism.

Biosynthesis of polysaccharide hyaluoronic acid (HA) by Streptococcus zooepidemicus is a carbon-intensive process. The carbon flux and factor(s) restricting HA yield were not well understood. Here, we investigated the function of genes involved in sucrose metabolism and identified targets limiting HA yield, which were exploited to construct efficient S. zooepidemicus strains for HA production. The sucrose uptake was addressed by deletion of scrA and scrB, which encodes sucrose-PTS permease and sucrose-6-phosphate hydrolase, respectively. We found that scrB was essential for the growth of S. zooepidemicus and HA biosynthesis, and accumulation of sucrose-6-phosphate was toxic. ΔscrB could not grow in THY-sucrose medium, while ΔscrA and ΔscrAΔscrB showed negligible growth defects. Overexpression of scrA significantly reduced biomass and HA production, while overexpression of scrB resulted in 26% increase of biomass and 30% increase of HA yield. We revealed that fructose-6-phosphate for HA biosynthesis mainly originates from glucose-6-phosphate. Deletion of scrK, a gene encoding hexokinase, led to 11% reduction of biomass and 12% decrease of HA yield, while deletion of hasE, a gene encoding phosphoglucoisomerase, resulted in the abolishment of HA biosynthesis and a significantly slow growth. We found that HA biosynthesis could be improved by directing carbon flux to fructose-6-phosphate. Deletion of fruA encoding the EII of fructose-PTS and fruK encoding phosphofructokinase showed no apparent effect on cell growth, but resulted in 22 and 27% increase of HA yield, respectively. Finally, a strain with 55% increase of HA was constructed by overexpression of scrB in ΔfruK. These results provide a solid foundation for further metabolic engineering of S. zooepidemicus for highly efficient HA production.

Reinforcement effect of poly(butylene succinate) (PBS)-grafted cellulose nanocrystal on toughened PBS/polylactic acid blends.

Poly(butylene succinate) (PBS)/polylactic acid (PLA) blends modified with dicumyl peroxide (DCP) were reinforced by PBS-g-cellulose nanocrystal (CNC) through melt mixing. PBS-g-CNC was prepared through in situ polymerization and its structure was confirmed by FTIR, (13)C NMR, XPS and GPC analysis after saponification. The morphological analysis of PBS/PLA/PBS-g-CNC composites before and after etched by CH2Cl2 shows that the addition of DCP and PBS-g-CNC could decrease the size of PBS as a dispersed phase in PLA matrix and improve the dispersion of PBS-g-CNC in both PBS and PLA phases, which could affect the crystallization and mechanical properties of composites. The crystallinity of PLA α'-phase crystal in PBS/PLA/PBS-g-CNC composites is increased obviously by the addition of PBS-g-CNC, leading to an increase of the crystallinity of the composites. PBS/PLA blends modified by DCP have high Notched Izod impact strength and moduli, and the values are increased by the addition of PBS-g-CNC. Both storage modulus and glass translation temperature of PBS/PLA blend are increased by DCP and PBS-g-CNC, which is proved by DMA results, showing a weak molecular segment mobility of PBS/PLA matrix. The addition of DCP decreases the crystallization temperature and crystallinity of PBS/PLA composite, but increases the thermal stability of composites, mostly because of the crosslink effect of DCP on PBS/PLA matrix.

Poly(butylene succinate-co-butylene adipate)/cellulose nanocrystal composites modified with phthalic anhydride.

As a kind of biomass nanofiller for polymers, cellulose nanocrystal (CNC) has good mechanical properties and reinforcing capability. To improve the compatibility of poly(butylene succinate-co-butylene adipate) (PBSA)/CNC composites, phthalic anhydride was used as a compatilizer during melt mixing, leading to the significant improvement of the mechanical properties and thermal stability of the composites, which is related to the better dispersion of CNC in the composites. The addition of phthalic anhydride could accelerate the crystallization of PBSA component as evidenced by the curves of isothermal crystallization of the composites, but had little effect on the crystalline polymorphs of PBSA component. The addition of phthalic anhydride could strongly improve the hydrophobicity of the composites. The good mechanical properties, fast crystallization and improved hydrophobicity of PBSA/CNC composites with phthalic anhydride are favor to their practical commercial utilization.

Acute effects of microcystins on the transcription of antioxidant enzyme genes in crucian carp Carassius auratus.

Recent evidences suggested that oxidative stress may play a significant role in the pathogenesis of MCs toxicity. In the present study, the acute effects of microcystins on the transcription of antioxidant enzyme genes were investigated in liver of crucian carp i.p.-injected with 50 mug MC-LReq per kg body weight (BW). We reported the cDNA sequences for four kinds of antioxidant enzyme (GSH-PX, CAT, Cu/Zn SOD, and GR) genes, and evaluated the oxidant stress induced by MCs through analyzing the transcription abundance of antioxidant enzyme genes using real-time PCR method. The time-dependent change of relative transcription abundance and expression of the antioxidant enzyme genes were determined at 1, 3, 12, 24, and 48 h. The transcription abundance varied among antioxidant enzymes, with GSH-PX and GR down-regulation, and CAT and SOD significantly upregulation. Based on these data, we tentatively concluded that the oxidant stress was induced by MCs, and caused the different response of the antioxidant enzyme genes.