Comparison of the medial midline and the anterolateral portal in ankle arthroscopy for the treatment of osteochondral lesions of the medial talus.

PURPOSE: To compare the clinical efficacy and complication rates between the medial midline and anterolateral portals in ankle arthroscopy for treating medial osteochondral lesions of the talus (OLTs). METHODS: We retrospectively analyzed patients with medial OLTs who underwent either a dual medial approach (via the medial midline and anteromedial portal) or a traditional approach (via the anterolateral and anteromedial portal) between June 2017 and January 2023. The degree of injury was evaluated by radiographs, computed tomography, and magnetic resonance imaging. Clinical outcomes were assessed using the visual analog scale (VAS), the American Orthopaedic Foot and Ankle Society (AOFAS) score, and the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) scoring system. The incidence of postoperative complications, including superficial peroneal nerve (SPN) injury, was evaluated in all patients. RESULTS: There were 39 patients in total; 16 patients underwent the dual medial approach, and 23 patients underwent the traditional approach. The mean age was 39.4 ± 9.0 years, and the mean follow-up duration was 18.7 ± 6.4 months. The clinical outcomes improved significantly in both groups (*P < 0.05), but there was no significant difference between the two groups (P > 0.05). Postoperative complications were mainly SPN injury. The incidence of SPN injury was 13.0% in the traditional approach group and 0% in the dual medial approach group, with no significant difference between the two groups (P > 0.05), but a trend of reduction in SPN injury was observed in the dual medial approach group. CONCLUSION: The dual medial approach can also treat medial OLTs well, providing clear visualization and more convenient operation and reducing the possibility of injury to the SPN compared with the traditional approach. Therefore, we consider that the MM portal would be a good alternative to the anterolateral portal in treating medial OLTs.

Ferric Oxide Nanocrystals-Embedded Co/Fe-MOF with Self-Tuned d-Band Centers for Boosting Urea-Assisted Overall Water Splitting.

A novel semiconductive Co/Fe-MOF embedded with Fe2 O3 nanocrystals (Fe2 O3 @CoFe-MOF) is developed as a trifunctional electrocatalyst for the urea oxidation reaction (UOR), oxygen evolution reaction (OER), and hydrogen evolution reaction for enhancing the efficiency of the hydrogen production via the urea-assisted overall water splitting. Fe2 O3 @CoFe-TPyP-MOF comprises unsaturated metal-nitrogen coordination sites, affording enriched defects, self-tuned d-band centers, and efficient π-π interaction between different layers. Density functional theory calculation confirms that the adsorption of urea can be optimized at Fe2 O3 @CoFe-TPyP-MOF, realizing the efficient adsorption of intermediates and desorption of the final product of CO2 and N2 characterized by the in situ Fourier transform infrared spectroscopy. The two-electrode urea-assisted water splitting device-assembled with Fe2 O3 @CoFe-TPyP-MOF illustrates a low cell voltage of 1.41 V versus the reversible hydrogen electrode at the current density of 10 mA cm-2 , attaining the hydrogen production rate of 13.13 µmol min-1 in 1 m KOH with 0.33 m urea. The in situ electrochemical Raman spectra and other basic characterizations of the used electrocatalyst uncover that Fe2 O3 @CoFe-TPyP-MOF undergoes the reversible structural reconstruction after the UOR test, while it demonstrates the irreversible reconstruction after the OER measurement. This work redounds the progress of urea-assisted water spitting for hydrogen production.

A comparison of treatment between mini T-plate and headless cannulated compression screw in calcaneal osteotomy.

PURPOSE: In clinical studies, we discovered that when using headless cannulated compression screw fixation, many patients complain of heel pain and frequently need to have the screws removed, whereas this occurrence is uncommon with plate fixation. This study aims to compare the clinical outcome of a mini T-plate and headless cannulated compression screws in calcaneal osteotomy. METHODS: We reviewed the medical records of patients who had calcaneal osteotomy performed by one senior chief surgeon in our hospital between January 2014 and May 2021. Thirty-nine patients met the selection criteria: 22 were fixed using a mini T-plate through a modified small "L" incision on the lateral aspect of the calcaneus and 17 were fixed using double screws through an oblique incision on the lateral aspect of the calcaneus. Then, we compared the patient demographics, surgical statistics, and postoperative complications in calcaneal osteotomy between a mini T-plate and double 6.5-mm headless cannulated compressed screws. RESULTS: Each patient attained radiographic union. The average age was 49.23±13.80 (range: 24-76) years and the average follow-up duration was 47.07±8.64 (range: 36-66) weeks. The average operation duration and times of intraoperative fluoroscopy were significantly lower in the mini T-plate group (P<0.05). There was a savings of $838.88 per patient when using double screws for fixation. The incidence of hardware-related pain and implant removal was lower in the mini T-plate group (P<0.05). There is no significant difference between the two groups in terms of delayed incision healing and clinical neurological complications (P>0.05). CONCLUSIONS: In calcaneal osteotomy, the operation duration, times of intraoperative fluoroscopy, hardware-related pain, and implant removal rate were lower with mini T-plate fixation than with double screws fixation. Therefore, we consider that the mini T-plate would be a good alternative to double screws in calcaneal osteotomy.

Experimental study on repair of cartilage defects in the rabbits with GelMA-MSCs scaffold prepared by three-dimensional bioprinting.

Cartilage damage is a common orthopedic disease, which can be caused by sports injury, obesity, joint wear, and aging, and cannot be repaired by itself. Surgical autologous osteochondral grafting is often required in deep osteochondral lesions to avoid the later progression of osteoarthritis. In this study, we fabricated a gelatin methacryloyl-marrow mesenchymal stem cells (GelMA-MSCs) scaffold by three-dimensional (3D) bioprinting. This bioink is capable of fast gel photocuring and spontaneous covalent cross-linking, which can maintain high viability of MSCs and provide a benign microenvironment to promote the interaction, migration, and proliferation of cells. In vivo experiments, further, proved that the 3D bioprinting scaffold can promote the regeneration of cartilage collagen fibers and have a remarkable effect on cartilage repair of rabbit cartilage injury model, which may represent a general and versatile strategy for precise engineering of cartilage regeneration system.

Study on Rice Grain Mildewed Region Recognition Based on Microscopic Computer Vision and YOLO-v5 Model.

This study aims to develop a high-speed and nondestructive mildewed rice grain detection method. First, a set of microscopic images of rice grains contaminated by Aspergillus niger, Penicillium citrinum, and Aspergillus cinerea are acquired to serve as samples, and the mildewed regions are marked. Then, three YOLO-v5 models for identifying regions of rice grain with contamination of Aspergillus niger, Penicillium citrinum, and Aspergillus cinerea in microscopic images are established. Finally, the relationship between the proportion of mildewed regions and the total number of colonies is analyzed. The results show that the proposed YOLO-v5 models achieve accuracy levels of 89.26%, 91.15%, and 90.19% when detecting mildewed regions with contamination of Aspergillus niger, Penicillium citrinum, and Aspergillus cinerea in the microscopic images of the verification set. The proportion of the mildewed region area of rice grain with contamination of Aspergillus niger/Penicillium citrinum/Aspergillus cinerea is logarithmically correlated with the logarithm of the total number of colonies (TVC). The corresponding determination coefficients are 0.7466, 0.7587, and 0.8148, respectively. This study provides a reference for future research on high-speed mildewed rice grain detection methods based on MCV technology.

A new strategy for the development of efficient impedimetric tobramycin aptasensors with metallo-covalent organic frameworks (MCOFs).

Two bimetallic CoNi-based metallo-covalent organic frameworks (MCOFs) were prepared and explored as the sensitive platforms of impedimetric aptasensors for efficient detection of tobramycin (TOB). The two CoNi-MCOFs were constructed using metallophthalocyanine tetra-amine (MPc-TA, M = Co2+ or Ni2+) and 4,4'-(1,10-phen-anthroline-2,9-diyl) dibenzaldehyde (PTD) as building units and further coordinating to the secondary metal ions (Ni2+ or Co2+) by phenanthroline. Interestingly, the immobilization ability of CoPc-TA-PTD(Ni) to TOB-targeted aptamer is higher than that of NiPc-TA-PTD(Co) due to its stronger binding interactions to aptamer. As a result, the CoPc-TA-PTD(Ni)-based aptasensor shows the superior TOB detection ability, giving a low detection limit of 0.07 fg mL-1 and satisfied sensing performances, such as high selectivity, good reproducibility, and excellent stability. Also, the aptasensor shows the acceptable applicability for detecting TOB in milk or chicken egg. This MCOFs-based sensing strategy could be extensively applied to detect other analytes by anchoring the corresponding probes.

Evaluation of the hyperbaric oxygen therapy on the flash visual evoked potential P2 in patients with severe traumatic brain injury.

BACKGROUND: Studies have shown that hyperbaric oxygen therapy (HBOT) can improve the extraction rate and latency of cortical evoked potential N20 in patients with severe traumatic brain injury, but there are only a few studies on the effect of flash visual evoked potential. OBJECTIVE: This study investigated the effect of hyperbaric oxygen therapy on the P2 wave of flash visual evoked potentials in patients with severe traumatic brain injury. METHODS: In total, we examined 40 TBI patients who received HBOT, in combination with medication, and 38 TBI patients who received medication alone. The FVEPs apparatus was used to detect the P2 wave extraction rate and the latency of the elicited waveform before and after treatment in both the medicated-only controls and HBOT-treated cohorts. RESULTS: Compared with the control group, the HBOT treatment group showed a higher P2 wave elicitation rate, and the P2 wave latency of the HBOT treatment group was significantly shortened (p < 0.05, all). CONCLUSIONS: HBOT, in combination with drug therapy, can significantly increase the P2 wave extraction rate and shorten P2 latency in patients with TBI.

Catkin-derived mesoporous carbon-supported molybdenum disulfide and nickelhydroxyloxide hybrid as a bifunctional electrocatalyst for driving overall water splitting.

In this work, a two-dimensional heterostructure of molybdenum disulfide (MoS2) and nickelhydroxyloxide (NiOOH) nanosheets supported on catkin-derived mesoporous carbon (C-MC) was constructed and exploited as an efficient electrocatalyst for overall water splitting. The C-MC nanostructure was prepared by pyrolyzing biomass material of catkin at 600 °C in N2 atmosphere. The C-MC network exhibited hollow nanotube structure and had a large specific surface area, comprising trace nitrogen and a large amount of oxygen vacancies. It further served as the support for the growth of NiOOH nanosheets (NiOOH@C-MC), which was combined with MoS2 nanosheets by in situ growth, yielding a multicomponent electrocatalyst (MoS2@NiOOH@C-MC). By integrating the superior hydrogen evolution reaction (HER) performance of MoS2, oxygen evolution reaction (OER) performance of NiOOH, and the fast electron transfer capability of C-MC, the prepared MoS2@NiOOH@C-MC illustrated a low potential of - 250 mV for HER and 1.51 V for OER at the current density of 10 mV cm-2. Consequently, when applied as the working electrode for driving overall water splitting in a two-electrode system, the bifunctional MoS2@NiOOH@C-MC electrocatalyst displayed a low cell voltage of 1.62 V at the current density of 10 mA cm-2. The present work provides a new strategy that uses biomass material for developing bifunctional electrocatalyst for overall water splitting.

A Combined Morphological and Molecular Evolutionary Analysis of Karst-Environment Adaptation for the Genus Urophysa (Ranunculaceae).

The karst environment is characterized by low soil water content, periodic water deficiency, and poor nutrient availability, which provides an ideal natural laboratory for studying the adaptive evolution of its inhabitants. However, how species adapt to such a special karst environment remains poorly understood. Here, transcriptome sequences of two Urophysa species (Urophysa rockii and Urophysa henryi), which are Chinese endemics with karst-specific distribution, and allied species in Semiaquilegia and Aquilegia (living in non-karst habitat) were collected. Single-copy genes (SCGs) were extracted to perform the phylogenetic analysis using concatenation and coalescent methods. Positively selected genes (PSGs) and clusters of paralogous genes (Mul_genes) were detected and subsequently used to conduct gene function annotation. We filtered 2,271 SCGs and the coalescent analysis revealed that 1,930 SCGs shared the same tree topology, which was consistent with the topology detected from the concatenated tree. Total of 335 PSGs and 243 Mul_genes were detected, and many were enriched in stress and stimulus resistance, transmembrane transport, cellular ion homeostasis, calcium ion transport, calcium signaling regulation, and water retention. Both molecular and morphological evidences indicated that Urophysa species evolved complex strategies for adapting to hostile karst environments. Our findings will contribute to a new understanding of genetic and phenotypic adaptive mechanisms of karst adaptation in plants.

Determination of VEGF165 using impedimetric aptasensor based on cyclohexanehexone-melem covalent-organic framework.

A porous nanostructured covalent-organic framework (COF) has been prepared via condensation polymerization between the two building blocks of melem and hexaketocyclohexane octahydrate (represented as M-HO-COF). Basic characterizations revealed that the M-HO-COF network was composed of C=N and highly conjugated aromatic moieties, along with a high surface area, large pore size, remarkable electrochemical activity, and strong bioaffinity toward aptamer strands. Given that the vascular endothelial growth factor 165 (VEGF165)-targeted aptamer was stably anchored over M-HO-COF via weak intermolecular forces, the prepared M-HO-COF network exhibited great potential as a sensitive and selective platform for the impedimetric VEGF165 aptasensor. Consequently, the M-HO-COF-based aptasensor displayed an ultralow limit of detection of 0.18 fg mL-1 within a wide range of VEGF165 concentrations from 1 fg mL-1 to 10 ng mL-1. Considering its strong fluorescence performance, excellent biocompatibility, and small nanosheet-like structure, the obtained COF-based aptasensor showed a superior sensing performance and regeneration capability after 7 regeneration cycles for the detection of osteosarcoma cells (K7M2 cells), which overexpressed with VEGF165, with a low limit of detection of 49 cells mL-1. For real f human serum samples, the obtained COF-based aptasensor exhibits acceptable mean apparent recoveries of 97.41% with a relative standard deviation of 4.60%. Furthermore, the proposed bifunctional aptasensor for the detection VEGF165 and K7M2 cells exhibited good stability, appropriate selectivity toward other biomarkers or normal cells, acceptable reproducibility, and applicability. A bifunctional sensing system was constructed for detecting osteosarcoma cells (K7M2 cells) and VEGF165 based on the a porous nanostructured covalent-organic framework (M-HO-COF) via condensation polymerization between melem and hexaketocyclohexane octahydrate. The M-HO-COF-based aptasensor displayed ultralow detection limit of 0.18 fg mL-1 toward VEGF165 and 49 cell mL-1 for K7M2 cells with high selectivity, acceptable reproducibility, and good stability.

0D/2D heteronanostructure-integrated bimetallic CoCu-ZIF nanosheets and MXene-derived carbon dots for impedimetric cytosensing of melanoma B16-F10 cells.

A novel heterogeneous architecture has been constructed integrating two-dimensional (2D) bimetallic CoCu-zeolite imidazole framework (CoCu-ZIF) and zero-dimensional (0D) Ti3C2Tx MXene-derived carbon dots (CDs) (represented by CoCu-ZIF@CDs). The prepared CoCu-ZIF@CDs were further explored as sensitive layer for anchoring B16-F10 cell-targeted aptamer strands and detecting B16-F10 cells from the biological environment. Basic characterization showed that CDs were homogeneously embedded within CoCu-ZIF NSs owing to their π-π stacking interaction, leading to outstanding fluorescence performance of the 0D/2D CoCu-ZIF@CD nanohybrid. As such, the CoCu-ZIF@CD-based cytosensor was applied to detect living B16-F10 cells through electrochemical techniques and cell imaging. Compared with CoCu-ZIF- and CD-based cytosensors, the constructed CoCu-ZIF@CD-based one showed superior sensing performance, with an extremely low limit of detection (LOD) of 33 cells∙mL-1 and a wide range of suspension concentration of 1 × 102-1 × 105 cells∙mL-1 B16-F10 cells. The developed cytosensor also demonstrated excellent detection performance, including cell imaging properties, good selectivity, high stability, and good reproducibility. By anchoring other probe molecules, the constructed CoCu-ZIF@CD-based biosensor can be extensively explored for early diagnosis of other analytes, thereby widening the applications of porous organic frameworks in biosensing and biomedical fields. A novel sensing system for melanoma B16-F10 cells based on a novel CoCu-ZIF@CD nanohybrid has been developed. The CoCu-ZIF@CDs-based cytosensor displayed an extremely low limit of detection (LOD) of 33 cells∙mL-1 within the wide range of B16-F10 cell concentration from 1 × 102 to 1 × 105 cells∙mL-1, accompanying with cell imaging properties, good selectivity, high stability, and well reproducibility.

Two-dimensional triazine-based porous framework as a novel metal-free bifunctional electrocatalyst for zinc-air batty.

A metal-free carbon catalyst, melem-cyanuric acid complex (MCAC), was prepared by hydrogen bonding assembly and further explored as a novel bifunctional electrocatalysts for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). The proposed MCAC network presented nanosheet-like structure, nitrogen-rich, and large specific surface area, which are close to the natures of graphitic carbon nitride (g-C3N4) and N-doped reduced graphene oxide (N-rGO), but giving much more defect active sites and regular framework structure. Compared with the g-C3N4, N-rGO and other reported carbon-nitride electrocatalysts, the MCAC nanosheets exhibited a lower overpotential of 1.45 V at a current density of 10 mA cm-2 for OER, along with a higher half-potential of 0.8 V and larger limit current density of -6.0 mA cm-2 for ORR. Density functional theory calculation revealed that the melem N atoms bonded with cyanurate greatly enhanced the OER activity by increasing the interaction between catalysts and intermediates. Furthermore, as a metal-free electrocatalyst, MCAC displayed superior reversible oxygen electrocatalytic activity, giving a small overpotential difference (0.76 V). The rechargeable zinc-air battery with MCAC as the air electrode in a two-electrode configuration showed a high open-circuit potential of 1.383 V and a specific capacity of 613.5 mA h gZn-1 at 10 mA cm-2. This work opens up a new avenue to develop advanced porous solids as metal-free electrocatalysts for the energy storage and conversion applications.

Electrohydrodynamic 3D Printing Scaffolds for Repair of Achilles Tendon Defect in Rats.

Tissue engineering (TE) studies for Achilles tendon (AT) defects are a difficult and popular field in orthopedic medical practice. In this study, we applied electrohydrodynamic three-dimensional (3D) printing technology to construct scaffolds made of poly-(ɛ-ɛ-caprolactone) (PCL) and Pluronic F127 (F127) with different mass-volume ratios. The fibers and porous capabilities of the scaffolds were controlled using this technology. We found that F127 improved the hydrophilicity and degradation of PCL in vitro. The PCL scaffolds with 5% F127 were mostly favorable for cell adhesion and growth, suggesting that the scaffolds had good biocompatibility in vitro. Scaffolds with 5% F127 seeded with C3H10T1/2 cells were transplanted into AT defects in rats. A histological analysis indicated that the TE scaffolds were beneficial for the accumulation and arrangement of collagen fibers. Thus, this study provides fundamental experimental data for future clinical applications regarding TE for ATs. Impact statement Electrohydrodynamic three-dimensional (3D) printing can be used to construct tissue-engineered scaffolds with controllable fibers and good porosity. Pluronic-F127 (F127) improved the hydrophilicity and degradation of the poly-(ɛ-ɛ-caprolactone) (PCL), and a better microscale structure was obtained. The scaffolds with 5% F127, with good pore structures, were favorable for C3H10T1/2 cell growth and cellular morphology, indicating that they had good biocompatibility. In vivo transplantation experiments showed that scaffolds with 5% F127 improved the arrangement of collagen fibers, encouraging their potential application in the construction of future tissue-engineered tendons.

Nanodiamonds and hydrogen-substituted graphdiyne heteronanostructure for the sensitive impedimetric aptasensing of myocardial infarction and cardiac troponin I.

A novel heteronanostructure of nanodiamonds (NDs) and hydrogen-substituted graphdiyne (HsGDY) (denoted as HsGDY@NDs) was prepared for the impedimetric aptasensing of biomarkers such as myoglobin (Myo) and cardiac troponin I (cTnI). Basic characterizations revealed that the HsGDY@NDs were composed of nanospheres with sizes of 200-500 nm. In these nanospheres, NDs were embedded within the HsGDY network. The HsGDY@NDs nanostructure, which integrated the good chemical stability and three-dimensional porous networks of HsGDY, and the good biocompatibility and electrochemical activity of NDs, could immobilize diverse aptamer strands and recognize target biomarkers. Compared with HsGDY- and NDs-based aptasensors, the HsGDY@NDs-based aptasensors exhibited superior sensing performances for Myo and cTnI, giving low detection limits of 6.29 and 9.04 fg mL-1 for cTnI and Myo, respectively. In addition, the HsGDY@NDs-based aptasensors exhibited high selectivity, good stability, reproducibility, and acceptable applicability in real human serum. Thus, the construction of HsGDY@NDs-based aptasensor is expected to broaden the application of porous organic frameworks in the sensing field and provide a prospective approach for the early detection of disease biomarkers.

Bacteriophage biocontrol of Shiga toxigenic Escherichia coli (STEC) O145 biofilms on stainless steel reduces the contamination of beef.

Shiga toxigenic Escherichia coli (STEC) can form biofilms and frequently cause serious foodborne illnesses. A strain of STEC O145:H25 (EC19990166) known to be a strong biofilm former was used to evaluate the efficacy of bacteriophage AZO145A against biofilms formed on stainless steel (SS) coupons. Exposure of STEC O145:H25 to phage AZO145A (1010 PFU/mL) for 2 h resulted in a 4.0 log10 reduction (P < 0.01) of planktonic cells grown in M9 broth at 24 °C for 24 h, while reductions were 2.0 log10 CFU/mL if these cells were grown for 48 h or 72 h prior to phage treatment. STEC O145 biofilms formed on SS coupons for 24, 48 and 72 h were reduced (P < 0.01) 2.9, 1.9 and 1.9 log10 CFU/coupon by phages. STEC O145 cells in biofilms were readily transferred from the surface of the SS coupon to beef (3.6 log10 CFU/coupon) even with as little as 10 s of contact with the meat surface. However, transfer of STEC O145 cells from biofilms that formed on SS coupons for 48 h to beef was reduced (P < 0.01) by 3.1 log10 CFU by phage (2 × 1010 PFU/mL) at 24 °C. Scanning electron microscopy revealed that bacterial cells within indentations on the surface of SS coupons were reduced by phage. These results suggest that bacteriophage AZO145A could be effective in reducing the viability of biofilm-adherent STEC O145 on stainless steel in food industry environments.

Nonenzymatic amperometric sensor for hydrogen peroxide released from living cancer cells based on hierarchical NiCo2O4-CoNiO2 hybrids embedded in partially reduced graphene oxide.

The synthesis of hierarchical NiCo2O4-CoNiO2 hybrids embedded in partially reduced graphene oxide (represented by NiCo2O4/CoNiO2@pPRGO) is described. They were derived from ultrathin CoNi-based zeolitic imidazolate framework (CoNi-ZIF) nanosheets vertically grew on three-dimensional (3D) pRGO networks by pyrolysis at different temperatures (300, 600, and 900 °C) in N2 atmosphere. Transmission electron microscopy, X-ray diffraction, and X-ray photoemission spectroscopy measurements showed that the metal coordination centers (Co or Ni) were transferred into NiCo2O4 spinel and CoNiO2 nanostructures, along with a small number of metallic states of Co and Ni. In view of good electrochemical conductivity and large specific surface area of pRGO, good catalytic activity of Co- and Ni-contained NPs, and homogeneous distribution of NPs within the pRGO network, the NiCo2O4/CoNiO2@pRGO600 nanohybrid calcined at 600 °C displayed superior electrocatalytic activity toward hydrogen peroxide (H2O2) reduction. A glassy carbon electrode modified with NiCo2O4/CoNiO2@pRGO600 was used for determination of H2O2 by amperometry at an applied potential of - 0.4 V vs. Ag/AgCl. The nonenzymatic amperometric sensor exhibited high sensitivity and low detection limit (0.41 µM) within a wide working range (5 µM-3 mM and 3-12 mM) toward H2O2, as well as good selectivity, reproducibility, and long-term stability. Benefiting from the good biocompatibility and remarkable analytical performances of NiCo2O4/CoNiO2@pRGO600, the assay was used to determine real-time H2O2 released from living cancer cells. Graphical abstract.

Efficient multifunctional electrocatalyst based on 2D semiconductive bimetallic metal-organic framework toward non-Pt methanol oxidation and overall water splitting.

As the efficient approaches for obtaining clean H2 energy, methanol oxidation (MOR) and water over slitting reactions have been increasingly essential. A series of novel semiconductive CoNi bimetal-organic framework (CoxNi3-x(HAB)2 MOF) have been prepared using hexaaminobenzene (HAB) as an organic linker. The obtained series of CoxNi3-x(HAB)2 MOFs were then explored as efficient multifunctional electrocatalysts for the non-Pt MOR and overall water splitting in alkaline medium. The basic characterizations of CoxNi3-x(HAB)2 MOFs revealed that they comprised multiple metal valence states (Co0/Co2+/Co3+ and Ni2+/Ni3+) and graphene-like nanostructures embedded with abundant CoNi alloy nanoparticles. Compared with the sole-metal MOFs (Co3(HAB)2 MOF and Ni3(HAB)2 MOF), the CoxNi3-x(HAB)2 MOF with a mass ratio of Co:Ni = 1:3 (CoxNi3-x(HAB)2 MOF-2) exhibited superior electrocatalytic performance for MOR. It gave a high current density of 92.8 mA cm-2 at 1.6 V vs. reversible hydrogen electrode (RHE) for MOR, along with the low overpotentials at the current density of 10 mV cm-2 (η10) and Tafel slopes toward hydrogen evolution reaction (η10 = 119 mV, Tafel slope = 46 mV dec-1) and oxygen evolution reaction (η10 = 1.35 V, Tafel slope = 26 mV dec-1). The analysis on the catalysis mechanism of MOR and water splitting in alkaline medium was also proposed. The voltages applied to the three- and two-electrode systems based on the bifunctional CoxNi3-x(HAB)2 MOF-2 catalyst for overall water splitting are 1.52 V vs. RHE and 1.45 V vs. silver/silver chloride (Ag/AgCl), respectively. This work provides a novel strategy for investigating the applications of promising two-dimensional semiconductive MOF as multifunctional electrocatalysts with boosted electrocatalytic activities in energy fields.

Resistance mechanisms adopted by a Salmonella Typhimurium mutant against bacteriophage.

Bacteriophages have key roles in regulating bacterial populations in most habitats. A Salmonella Typhimurium mutant (N18) with impaired sensitivity to phage fmb-p1 was obtained and examined, the adsorption efficiency of fmb-p1 to N18 was reduced to 6%, compared to more than 97% for wild type S. Typhimurium CMCC50115. Reduced adsorption was accompanied by a reduction of 90% in the LPS content compared to wild type. Electron microscopy showed phage scattered around N18 with minimal engagement, while the phage were efficiently adsorbed to the wild type with tails oriented towards the bacterial surface. Evidence suggests fmb-p1 can slightly infect N18 and this does not give rise to an increase of phage titer. RT-qPCR data show that several Salmonella genes involved in lipopolysaccharide synthesis and five virulence related genes were down-regulated upon exposure of N18 to phage fmb-p1. In contrast, phage resistance related genes such as the SOS response, restriction-modification (RM), and Cas1 gene were up-regulated in N18. These data suggest that although inefficient adsorption and entry is the primary mechanism of resistance, transcriptional responses to phage exposure indicate that alternative resistance mechanisms against phage infection are also brought to bear, including digestion of phage nucleic acids and activation of the SOS. These findings may help develop strategies for biocontrol of Salmonella where multi-resistant bacteria are encountered or emerge in applications for food production, bioremediation or wastewater treatment.

The reduction of melatonin levels is associated with the development of preeclampsia: a meta-analysis.

OBJECTIVE: The aim of this analysis was to demonstrate the association between melatonin levels and the development of preeclampsia. METHODS: Standardized mean difference (SMD) with 95% confidence interval (CI) was calculated using a random effects model. RESULTS: The pooled SMD between case and control was 1.40 (95% CI: 0.26, 2.55; P = 0.02). And the pooled SMD between mild PE and severe PE was 5.25 (95% CI: 1.5, 9.01; P = 0.006). CONCLUSION: The meta-analysis illustrated that melatonin concentration was significantly lower in women with preeclampsia, and correlated with the severity of the disease.

Design and Properties of an Immobilization Enzyme System for Inulin Conversion.

A commercial inulinase could convert inulin into fructose, which was optimized to be entrapped in the calcium alginate-gelatin beads with the immobilization yield of 86% for free inulinase activities. The optimum pH values and temperatures were 4.5 and 40 °C for the free enzyme and 5.0-5.5 and 45-50 °C for the immobilized enzyme. The kinetic parameters of V max and K m were 5.24 µmol/min and 57.6 mg/mL for the free inulinase and 4.32 µmol/min and 65.8 mg/mL for the immobilized inulinase, respectively. The immobilized enzyme retained 80% of its initial activities at 45 °C for 4 days, which could exhibit better thermal stability. The reuse of immobilized inulinase throughout the continuous batch operations was explored, which had better reusability of the immobilized biocatalyst. At the same time, the stability of immobilized enzyme in the continuous packed-bed bioreactor was estimated, which showed the better results and had its potential scale-up fructose production for inulin conversion.