Comparing Mechanical Bowel Preparation With Both Oral and Systemic Antibiotics Versus Mechanical Bowel Preparation and Systemic Antibiotics Alone for the Prevention of Surgical Site Infection After Elective Colorectal Surgery: A Meta-Analysis of Randomized Controlled Clinical Trials.

BACKGROUND: The discussion on the role of mechanical bowel preparation and oral antibiotics in elective colorectal surgery is still ongoing. OBJECTIVE: This meta-analysis aimed to determine whether oral systemic antibiotics with mechanical bowel preparation are superior to systemic antibiotics and mechanical bowel preparation for prophylaxis of bacterial infection during elective colorectal operation. DATA SOURCES: Embase, PubMed, and the Cochrane Library were searched using the terms oral, antibiotics/antimicrobial, colorectal/rectal/colon/rectum, and surgery/operation. STUDY SELECTION: All of the available randomized controlled trials that compared the efficacy of combined oral and systemic antibiotics and mechanical bowel preparation with systemic antibiotics alone and mechanical bowel preparation in colorectal surgery and defined surgical site infection based on Centers for Disease Control and Prevention criteria were included. INTERVENTION: All of the statistical analyses were performed using Review Manager 5.2 software. A fixed model was used if there was no evidence of heterogeneity; otherwise, a random-effects model was used. MAIN OUTCOME MEASURES: We focused on incidence of surgical site infection among the groups. RESULTS: Seven randomized controlled trials that consisted of 1769 cases were eligible for analysis. We found that both total surgical site infection and incisional surgical site infection were significantly reduced in patients who received oral systemic antibiotics and mechanical bowel preparation compared with patients who received systemic antibiotics alone and mechanical bowel preparation (total: 7.2% vs 16.0%, p < 0.00001; incisional: 4.6% vs 12.1%, p < 0.00001). However, no significant difference was detected in the rate of organ/space surgical site infection (4.0% vs 4.8%; p = 0.56) after elective colorectal surgery. LIMITATIONS: The meta-analysis was limited by the risk of bias because a majority of the studies did not use the blinding method. CONCLUSIONS: Oral systemic antibiotics and mechanical bowel preparation significantly lowered the incidence of surgical site infection after elective colorectal surgery compared with systemic antibiotics alone and mechanical bowel preparation.

Carbon quantum dots-modified Z-scheme Bi12O17Cl2/NiAl-LDH for significantly boosting photocatalytic CO2 reduction.

Photocatalytic reduction of CO2 to high-energy products is an effective way to utilize solar energy and mitigate the greenhouse effect. In this paper, a series of CQDs/Bi12O17Cl2/NiAl-LDH (C/BOC/LDH) photocatalysts were prepared via a one-pot hydrothermal method, demonstrated excellent photocatalytic CO2 reduction performance. In the case of only water without any photosensitizer and sacrificial agent, the CO production rate on C/0.3BOC/LDH reached 16.4 µmol·g-1h-1, which is 6.7 times higher than that of the original LDH. The construction of Z-scheme heterojunctions inhibited the recombination of electrons with holes. The unique up-conversion PL behavior of CQDs benefitted the absorption of energy in the NIR by the photocatalyst. This study provides meaningful assistance for the design and construction of a ternary photocatalytic system with Z-scheme heterojunction and carbon-based co-catalyst.

Fabrication of a ternary NiS/ZnIn2S4/g-C3N4 photocatalyst with dual charge transfer channels towards efficient H2 evolution.

As a renewable green energy, hydrogen has received widespread attention due to its huge potential in solving energy shortages and environment pollution. In this paper, a one-step solvothermal method was applied to grow ultra-thin g-C3N4 (UCN) nanosheets and NiS nanoparticles on the surface of ZnIn2S4 (ZIS). A ternary NiS/ZnIn2S4/ultra-thin-g-C3N4 composite material with dual high-speed charge transfer channels was constructed for the advancement of the photocatalytic H2 generation. The optimal ternary catalyst 1.5wt.%NiS/ZnIn2S4/ultra-thin-g-C3N4 (NiS/ZIS/UCN) achieved a H2 evolution yield reached to 5.02 mmolg-1h-1, which was 5.23 times superior than that of pristine ZnIn2S4 (0.96 mmolg-1h-1) and even outperform than that of the best precious metal modified 3.0 wt%Pt/ZnIn2S4 (4.08 mmolg-1h-1). The AQY at 420 nm could be achieved as high as 30.5%. The increased photocatalytic performance of NiS/ZIS/UCN could be ascribed to the type-I heterojunctions between intimated ZIS and UCN. In addition, NiS co-catalyst with large quantity of H2 evolution sites, could result in efficient photo-induced charges separation and migration. Furthermore, the NiS/ZIS/UCN composite exhibited excellent H2 evolution stability and recyclability. This work would also offer a reference for the design and synthesis of ternary co-catalyst with heterojunction composite for green energy conversion.

Fabrication of a dual S-scheme Bi7O9I3/g-C3N4/Bi3O4Cl heterojunction with enhanced visible-light-driven performance for phenol degradation.

S-scheme heterostructure can facilitate the separation of carriers while maintain outstanding redox capacity. A series of ternary Bi7O9I3/g-C3N4/Bi3O4Cl photocatalytic system was triumphantly synthesized via oil bath method in this work and used in photocatalytic degradation of phenol. The optimal TOC removal rate reached up to 93.57% under illumination for 160 min, which was slightly lower than phenol photodegradation (about 100%, 100 min). Correspondingly, the apparent rate constants for the decay of phenol are determined to be 0.0211 min-1. The experiment of free radical capture indicated that ·OH and ·O2- were the major oxidizing substances to degrade phenol. The products of phenol photodegradation were identified by high performance liquid chromatography (HPLC) and a possible degradation pathway was proposed. The characterization analysis and density functional theory (DFT) calculations demonstrated that dual S-scheme charge migration was generated at the interface of Bi7O9I3, g-C3N4 and Bi3O4Cl, contributing to an efficient separation of light-excited carriers. In the field of environmental remediation, the discovery of this work could open up promising vistas for designing bismuth-based ternary heterostructures with application potentiality.

A NiS co-catalyst decorated Zn3In2S6/g-C3N4 type-II ball-flower-like nanosphere heterojunction for efficient photocatalytic hydrogen production.

Promoting the separation of photogenerated electron-hole pairs and enhancing the charge carrier transfer are critical in photocatalysis. In our work, a ball-flower-like NiS/Zn3In2S6/g-C3N4 photocatalyst fabricated by a hydrothermal method exhibited superior performance for photocatalytic water splitting. The optimized 2.0% NiS/Zn3In2S6/g-C3N4 rivaled noble metal based Pt/g-C3N4 and showed an apparent quantum efficiency (AQE) of 24.3% at 420 nm, with a H2 yield of 4.135 mmol g-1 h-1, which was 30.4 and 9.51 times that of pure g-C3N4 and binary Zn3In2S6/g-C3N4 composites, respectively. The experimental and characterization results suggested that the heterojunction formed between Zn3In2S6/g-C3N4 and the decorating NiS co-catalyst cooperatively suppressed the electron-hole recombination and facilitated the charge carrier transfer, thus resulting in significant improvement of the H2 evolution performance. Moreover, the increased specific surface area and the enhanced visible-light absorption also contributed to superior water splitting performance. The prepared ternary catalytic system with the heterojunction and non-noble metal co-catalyst has great potential as an alternative to noble metals for achieving cost-efficient water splitting systems.

Recent Progress of Transition Metal Phosphides for Photocatalytic Hydrogen Evolution.

Photocatalytic hydrogen evolution can effectively alleviate the troublesome global energy crisis by converting solar energy into the chemical energy of hydrogen. In order to realize efficient hydrogen generation, a variety of semiconductor materials have been extensively investigated, including TiO2 , CdS, g-C3 N4 , metal-organic frameworks (MOFs), and others. In recent years, to achieve higher photocatalytic performance and reach the level of large-scale industrial applications, photocatalysts decorated with transition metal phosphides (TMPs) have shone brightly because of their low cost, stable physical and chemical properties, and substitution for precious metals of TMPs. This Review highlights the preparation methods and properties associated with photocatalysis of TMPs. Moreover, the H2 generation efficiency of photocatalysts loaded with TMPs and the roles of TMPs in catalytic systems are also studied systematically. Apart from being co-catalysts, several TMPs can also serve as host catalysts to boost the activity of photocatalytic composites. Finally, the development prospects and challenges of TMPs are put forward, which is valuable for future researchers to expand the application of TMPs in photocatalytic directions and to develop more active photocatalytic systems.

Enhanced Thermoelectric Properties of Bilayer-Like Structural Graphene Quantum Dots/Single-Walled Carbon Nanotubes Hybrids.

In order to improve the thermoelectric properties of single-walled carbon nanotubes (SWCNTs), bilayer-like structures of graphene quantum dots (GQDs) and SWCNTs films (b-GQDs/SWCNTs) were prepared by directly coating GQDs on the surface of SWCNTs films. Compared to pristine SWCNT films (p-SWCNTs), the electrical conductivity of b-GQDs/SWCNTs increased while their Seebeck coefficient decreased. The special interface structure of GQDs and SWCNTs can not only improve carrier transport to increase electrical conductivity but also scatter phonons to reduce thermal conductivity. A maximum power factor (PF) of 51.2 µW·m-1·K-2 is obtained at 298 K for the b-GQDs/SWCNTs (2:100), which is higher than the PF of 40.9 µW·m-1·K-2 by p-SWCNTs. Incorporation of GQDs shows an obvious improvement in power factor and a significant reduction in the thermal conductivity for SWCNTs, and thus, preparation of b-GQDs/SWCNTs provides a new strategy to enhance the thermoelectric properties of SWCNTs-based materials.

Two three-dimensional networks in the binary molecular adducts 4-methylimidazolium hydrogen terephthalate and bis(4-methylimidazolium) terephthalate.

Both the 1:1 and 2:1 molecular adducts of 4-methylimidazole (4-MeIm) and terephthalic acid (H2TPA) are organic salts, viz. C4H7N2+.C8H5O4-, (I), and 2C4H7N2+.C8H4O4(2-), (II), respectively. The component ions in (I) are linked by N-H...O and O-H...O hydrogen bonds into continuous two-dimensional layers built from R6(4)(32) hydrogen-bond motifs running parallel to the (100) plane. These adjacent two-dimensional layers are in turn linked by a combination of C-H...O, C-H...pi and pi-pi interactions into a three-dimensional network. In the crystal structure of (II), with the anion located on an inversion centre, only N-H...O hydrogen bonds result in two-dimensional layers built from R8(8)(42) hydrogen-bond motifs running parallel to the (102) plane. Being similar to those in (I), these layers are also linked by means of C-H...O, C-H...pi and pi-pi interactions, forming a three-dimensional network. This study indicates that, on occasion, a change of the reactant concentration can exert a pivotal influence on the construction of supramolecular structures based on hydrogen bonds.

{N,N'-Bis[(E)-3-phenyl-allyl-idene]ethane-1,2-diamine}dichloridozinc(II).

In the title compound, [ZnCl(2)(C(20)H(20)N(2))], the Zn(II) atom is four coordinated in a distorted tetra-hedral geometry by two N atoms of the Schiff base ligand and by two Cl atoms. Edge-to-face C-H⋯π inter-actions exist between mol-ecules, with a dihedral angle of 37.8 (1)° between the benzene ring planes and a shortest H⋯centroid distance of 3.62 (5) Å.

Bis(2-amino-pyrimidine-κN)dibromidozinc(II).

The title compound, [ZnBr(2)(C(4)H(5)N(3))(2)], is a mononuclear complex in which the Zn(II) ions have distorted tetra-hedral coordination geometry. The Zn(II) ion binds to two N atoms from two different 2-amino-pyrimidine ligands and two bromide ions. N-H⋯N hydrogen bonds link the mol-ecules to form a one-dimensional supra-molecular structure. The supra-molecular chains are parallel to each other and N-H⋯Br hydrogen bonds link them into a two-dimensional network in the ac plane. Additionally, there are strong π-π inter-actions [centroid-centroid distance = 3.403 (3) Å].

PEDOT:PSS/graphene quantum dots films with enhanced thermoelectric properties via strong interfacial interaction and phase separation.

The typical conductive polymer of PEDOT:PSS has recently attracted intensive attention in thermoelectric conversion because of its low cost and low thermal conductivity as well as high electrical conductivity. However, compared to inorganic counterparts, the relatively poor thermoelectric performance of PEDOT:PSS has greatly limited its development and high-tech applications. Here, we report a dramatic enhancement in the thermoelectric performance of PEDOT:PSS by constructing unique composite films with graphene quantum dots (GQDs). At room temperature, the electrical conductivity and Seebeck coefficient of PEDOT:PSS/GQDs reached to 7172 S/m and 14.6 µV/K, respectively, which are 30.99% and 113.2% higher than those of pristine PEDOT:PSS. As a result, the power factor of the optimized PEDOT:PSS/GQDs composite is 550% higher than that of pristine PEDOT:PSS. These significant improvements are attributed to the ordered alignment of PEDOT chains on the surface of GQDs, originated from the strong interfacial interaction between PEDOT:PSS and GQDs and the separation of PEDOT and PSS phases. This study evidently provides a promising route for PEDOT:PSS applied in high-efficiency thermoelectric conversion.