Hierarchically Porous Carbons with Highly Curved Surfaces for Hosting Single Metal FeN4 Sites as Outstanding Oxygen Reduction Catalysts.

Iron-nitrogen-carbon (FeNC) materials have emerged as a promising alternative to platinum-group metals for catalyzing the oxygen reduction reaction (ORR) in proton-exchange-membrane fuel cells. However, their low intrinsic activity and stability are major impediments. Herein, an FeN-C electrocatalyst with dense FeN4 sites on hierarchically porous carbons with highly curved surfaces (denoted as FeN4 -hcC) is reported. The FeN4 -hcC catalyst displays exceptional ORR activity in acidic media, with a high half-wave potential of 0.85 V (versus reversible hydrogen electrode) in 0.5 m H2 SO4 . When integrated into a membrane electrode assembly, the corresponding cathode displays a high maximum peak power density of 0.592 W cm-2 and demonstrates operating durability over 30 000 cycles under harsh H2 /air conditions, outperforming previously reported Fe-NC electrocatalysts. These experimental and theoretical studies suggest that the curved carbon support fine-tunes the local coordination environment, lowers the energies of the Fe d-band centers, and inhibits the adsorption of oxygenated species, which can enhance the ORR activity and stability. This work provides new insight into the carbon nanostructure-activity correlation for ORR catalysis. It also offers a new approach to designing advanced single-metal-site catalysts for energy-conversion applications.

Electrical stimulation therapy for peripheral nerve injury.

Peripheral nerve injury is common and frequently occurs in extremity trauma patients. The motor and sensory impairment caused by the injury will affect patients' daily life and social work. Surgical therapeutic approaches don't assure functional recovery, which may lead to neuronal atrophy and hinder accelerated regeneration. Rehabilitation is a necessary stage for patients to recover better. A meaningful role in non-pharmacological intervention is played by rehabilitation, through individualized electrical stimulation therapy. Clinical studies have shown that electrical stimulation enhances axon growth during nerve repair and accelerates sensorimotor recovery. According to different effects and parameters, electrical stimulation can be divided into neuromuscular, transcutaneous, and functional electrical stimulation. The therapeutic mechanism of electrical stimulation may be to reduce muscle atrophy and promote muscle reinnervation by increasing the expression of structural protective proteins and neurotrophic factors. Meanwhile, it can modulate sensory feedback and reduce neuralgia by inhibiting the descending pathway. However, there are not many summary clinical application parameters of electrical stimulation, and the long-term effectiveness and safety also need to be further explored. This article aims to explore application methodologies for effective electrical stimulation in the rehabilitation of peripheral nerve injury, with simultaneous consideration for fundamental principles of electrical stimulation and the latest technology. The highlight of this paper is to identify the most appropriate stimulation parameters (frequency, intensity, duration) to achieve efficacious electrical stimulation in the rehabilitation of peripheral nerve injury.

Identification of the Catalytically Dominant Iron Environment in Iron- and Nitrogen-Doped Carbon Catalysts for the Oxygen Reduction Reaction.

For large-scale utilization of fuel cells in a future hydrogen-based energy economy, affordable and environmentally benign catalysts are needed. Pyrolytically obtained metal- and nitrogen-doped carbon (MNC) catalysts are key contenders for this task. Their systematic improvement requires detailed knowledge of the active site composition and degradation mechanisms. In FeNC catalysts, the active site is an iron ion coordinated by nitrogen atoms embedded in an extended graphene sheet. Herein, we build an active site model from in situ and operando 57Fe Mössbauer spectroscopy and quantum chemistry. A Mössbauer signal newly emerging under operando conditions, D4, is correlated with the loss of other Mössbauer signatures (D2, D3a, D3b), implying a direct structural correspondence. Pyrrolic N-coordination, i.e., FeN4C12, is found as a spectroscopically and thermodynamically consistent model for the entire catalytic cycle, in contrast to pyridinic nitrogen coordination. These findings thus overcome the previously conflicting structural assignments for the active site and, moreover, identify and structurally assign a previously unknown intermediate in the oxygen reduction reaction at FeNC catalysts.

Effect and Mechanism of Bifidobacterium animalis B94 in the Prevention and Treatment of Liver Injury in Rats.

Objective: To investigate the effect of Bifidobacterium animalis B94 on the prevention and treatment of liver injury in rats and to elucidate the underlying mechanism of this relationship. Methods: Specific pathogen-free (SPF) rats were selected as the healthy control group, liver injury group and B94 treatment group, with 6 rats in each group. After the model was established, the experimental animals were tested for serum liver function indicators, gut microbiota composition, metabolite composition, and histopathology. Results: The albumin/globulin ratio and serum TBA, alanine aminotransferase, aspartate aminotransferase, and indirect bilirubin levels in the B94 treatment group were significantly lower than those in the liver injury group. 16S rRNA analysis showed that the gut microbiota of the three groups of rats were significantly different. Metabolic profile analysis showed that there were significant differences in the gut metabolomes of the three groups. Haematoxylin-eosin staining of the intestinal mucosa and liver tissues showed that the degree of liver and intestinal tissue damage in the B94 treatment group was significantly lower than that in the liver injury group. Conclusion: Bifidobacterium animalis B94 can affect the process of liver injury in rats by improving liver function, reducing intestinal damage, and regulating gut microbiota and metabolite production.

Facilitating the acidic oxygen reduction of Fe-N-C catalysts by fluorine-doping.

As the alternatives to expensive Pt-based materials for the oxygen reduction reaction (ORR), iron/nitrogen co-doped carbon catalysts (FeNC) with dense FeNx active sites are promising candidates to promote the commercialization of proton exchange membrane fuel cells. Herein, we report a synthetic approach using perfluorotetradecanoic acid (PFTA)-modified metal-organic frameworks as precursors for the synthesis of fluorine-doped FeNC (F-FeNC) with improved ORR performance. The utilization of PFTA surfactants causes profound changes of the catalyst structure including F-doping into graphitic carbon, increased micropore surface area and Brunauer-Emmett-Teller (BET) surface area (up to 1085 m2 g-1), as well as dense FeNx sites. The F-FeNC catalyst exhibits an improved ORR activity with a high E1/2 of 0.83 V (VS. RHE) compared to the pristine FeNC material (E1/2 = 0.80 V). A fast decay occurs in the first 10 000 potential cycles for the F-FeNC catalyst, but high durability is still maintained up to another 50 000 cycles. Density functional theory calculations reveal that the strongly withdrawing fluorine atoms doped on the graphitic carbon can optimize the electronic structure of the FeNx active center and decrease the adsorption energy of ORR intermediates.

Systematic study of precursor effects on structure and oxygen reduction reaction activity of FeNC catalysts.

In this work, the effect of porphyrin loading and template size is varied systematically to study its impact on the oxygen reduction reaction (ORR) activity and selectivity as followed by rotating ring disc electrode experiments in both acidic and alkaline electrolytes. The structural composition and morphology are investigated by 57Fe Mössbauer spectroscopy, transmission electron microscopy, Raman spectroscopy and Brunauer-Emmett-Teller analysis. It is shown that with decreasing template size, specifically the ORR performance towards fuel cell application gets improved, while at constant area loading of the iron precursor (here expressed in number of porphyrin layers), the iron signature does not change much. Moreover, it is well illustrated that too large area loadings result in the formation of undesired side phases that also cause a decrease in the performance, specifically in acidic electrolyte. Thus, if the impact of morphology is the focus of research it is important to consider the area loading rather than its weight loading. At constant weight loading, beside morphology the structural composition can also change and impact the catalytic performance. This article is part of the theme issue 'Bio-derived and bioinspired sustainable advanced materials for emerging technologies (part 2)'.

57Fe-Enrichment effect on the composition and performance of Fe-based O2-reduction electrocatalysts.

Pt-group metal (PGM)-free catalysts of the Me-N-C type based on abundant and inexpensive elements have gained importance in the field of oxygen reduction reaction (ORR) electrocatalysis due to their promising ORR-activities. Their insufficient stability, however, has fueled the interest in obtaining an in-depth understanding of their composition, which requires highly sensitive techniques compatible with their low metal contents (typically <5 wt%). In the particular context of iron-based materials, 57Fe-Mössbauer spectroscopy is often used to provide such compositional information, but requires (partially) 57Fe-enriched precursors. As a consequence, the extrapolation of conclusions drawn from Mössbauer measurements on 57Fe-enriched catalysts to equivalent materials with the standard isotope distribution relies on the assumption that the metal precursor's isotopic profile does not affect the catalysts' composition and ORR-activity. To verify this hypothesis, in this study we prepared two series of Fe-based catalysts using distinctively different synthesis approaches and various relative contents of 57Fe-enriched precursors, and observed that the extent of the latter parameter significantly affected the catalysts' ORR-activity. This effect was successfully correlated with the Fe-speciation of the catalysts inferred from the characterization of these samples with Mössbauer and X-ray absorption spectroscopies. Ultimately, these results highlight the crucial importance of verifying the consistency of the catalysts' activity and composition upon comparing standard and 57Fe-enriched samples.

The emergency surgical infection management checklist of hospitalized patients with coronavirus disease 2019 (COVID-19) in Zhejiang, China.

The novel coronavirus disease 2019 (COVID-19) epidemic broke out in 2019, it is highly contagious, and the infection rate among medical staff is high. The management of infection prevention and control during emergency surgery of COVID-19 patients has been outlined and the perioperative infection management checklist for emergency surgery of COVID-19 patients has been summarized and validated. There have been 13 emergency surgeries performed on COVID-19 patients at our hospital during this time. Two cases were cured and discharged, and the others were discharged after improvement and transferred to further rehabilitation, 30-day mortality of the emergency surgical is 0%. Once the emergency surgery protocol in the hospital is successfully established, emergency surgery can be performed as soon as the surgical planning decision is made, and the operating room can be prepared for use at any time. The incidence of surgical site infection (SSI) was largely higher than that of ordinary patients in the same time; however, the successful implementation of emergency surgery for COVID-19 had positive significance in reducing the incidence of death, risk of bleeding, and hypoxia. The current cumulative cure rate of COVID-19 in our hospital is 98%, patient mortality rate is 0%, and the incidence of COVID-19 infection in medical staff is 0%. The emergency surgical infection management checklist is feasible and effective in guiding the preoperative and intraoperative surgical procedures.

Potential-Induced Spin Changes in Fe/N/C Electrocatalysts Assessed by In Situ X-ray Emission Spectroscopy.

The commercial success of the electrochemical energy conversion technologies required for the decarbonization of the energy sector requires the replacement of the noble metal-based electrocatalysts currently used in (co-)electrolyzers and fuel cells with inexpensive, platinum-group metal-free analogs. Among these, Fe/N/C-type catalysts display promising performances for the reduction of O2 or CO2 , but their insufficient activity and stability jeopardize their implementation in such devices. To circumvent these issues, a better understanding of the local geometric and electronic structure of their catalytic active sites under reaction conditions is needed. Herein we shed light on the electronic structure of the molecular sites in two Fe/N/C catalysts by probing their average spin state with X-ray emission spectroscopy (XES). Chiefly, our in situ XES measurements reveal for the first time the existence of reversible, potential-induced spin state changes in these materials.

Evaluation of disinfection procedures in a designated hospital for COVID-19.

BACKGROUND: Coronavirus disease 2019 has spread globally and been a public health emergency worldwide. It is important to reduce the risk of healthcare associated infections among the healthcare workers and patients. This study aimed to investigate the contamination of environment in isolation wards and sewage, and assess the quality of routine disinfection procedures in our hospital. METHODS: Routine disinfection procedures were performed 3-times a day in general isolation wards and 6-times a day in isolated ICU wards in our hospital. Environmental surface samples and sewage samples were collected for viral RNA detection. Severe acute respiratory syndrome coronavirus 2 RNA detection was performed with quantitative reverse transcription polymerase chain reaction. RESULTS: A total of 163 samples were collected from February 6 to April 4. Among 122 surface samples, 2 were positive for severe acute respiratory syndrome coronavirus 2 RNA detection. One was collected from the flush button of the toilet bowl, and the other was collected from a hand-basin. Although 10 of the sewage samples were positive for viral RNA detection, all positive samples were negative for viral culture. CONCLUSION: These results revealed the routine disinfection procedures in our hospital were effective in reducing the potential risk of healthcare associated infection. Two surface samples were positive for viral detection, suggesting that more attention should be paid when disinfecting places easy to be ignored.

An interventional implementation project: hand hygiene improvement.

BACKGROUND: Good hand hygiene is the most effective basic measure for preventing hospital-acquired infections. This research project, which originated from a project report on improving hand hygiene at a general hospital in Hangzhou, Zhejiang, China, aimed to investigate the effectiveness of hand hygiene improvement among the hospital staff. METHODS: Since 2017, a hand hygiene improvement project involving the staff of a 2,500-bed general teaching hospital in Zhejiang, China, has been carried out. This study summarized the implementation and effectiveness of the project, which is based on the five factors of systematic evaluation. The research summary was divided into three phases: phase I (December 2017 to August 2018), phase 2 (September 2018 to April 2019), and phase 3 (May 2019 to December 2019). The data of hand hygiene compliance rates of different groups of professionals in the different research periods were statistically analyzed. RESULTS: The results showed that continuous intervention led to a gradual increasing trend (Ptrend<0.001) in the hand hygiene implementation rate with as the intervention time and phases progressed. The hand hygiene compliance rates differed significantly during different phases (76.61%, 79.95%, and 83.34% in phases 1, 2, and 3, respectively, P<0.001). At the same time, the compliance rates of hand hygiene at each phase differed significantly between different professions (P<0.001, the compliance rate of hand hygiene among nurses was the highest and lowest among workers). The compliance rate of hand hygiene for different professions during the three phases were: nurses, 84.73%; doctors, 78.35%; interns, 77.62%; and other hospital workers, 72.79%. CONCLUSIONS: The hand hygiene compliance rate was effectively improved among the hospital staff after the implementation of the hand hygiene improvement project. In this hospital, the project yielded remarkable results. Hand hygiene must be continuously practiced and improved to develop good habits. Effective and detailed planning as well as key factors, such as hand hygiene facilities, information monitoring, the active participation and response of employees, training and education, and supervision and feedback, could help to guarantee the effectiveness of the project.

Coronavirus disease 2019: MRI examination procedures and infection prevention and protection.

BACKGROUND: Though chest computed tomography (CT) and digital radiography (DR) is important in the diagnosis and treatment of COVID-19, for patients with COVID-19 who may need magnetic resonance imaging (MRI) due to other complications, we proposed the MRI procedures for patients and medical staff to reduce the risk of infection between them. METHODS: Combining two cases in our hospital and other literature, a solution about the procedure and necessary preventive and protective measures for MRI examination of COVID-19 patients is proposed for peer reference with the help of experts from our hospital infection-control department. The solution that meets the hospital infection-control regulations covers five aspects including the layout requirements for the MRI room in the radiology department, preparation before admission, preparation of medical staff, preparation of patients, and terminal disinfection after MRI examination. Radiology personnel should strictly abide by the regulations on infection prevention and control. MRI technicians who have been in close contact with COVID-19 patients should receive strict medical observation for two weeks. Each step should be performed carefully to minimize the risk of hospital infection. RESULTS: A solution that includes five aspects was formulated to prevent the potential contamination during the MRI scan for COVID-19 patients. These five aspects are layout requirements in the MRI room, preparation before admission, preparation of medical staff, preparation of patients, and terminal disinfection after an examination. MRI technicians who have been in close contact with COVID-19 patients should receive strict medical observation for two weeks. CONCLUSIONS: To prevent and control the potential hospital infection during the MRI examination for COVID-19 patients, a solution including five aspects was initially proposed.

SARS-CoV-2 RNA detection of hospital isolation wards hygiene monitoring during the Coronavirus Disease 2019 outbreak in a Chinese hospital.

OBJECTIVES: The aim of this paper was to monitor the presence of SARS-Cov-2 among hospital environment surfaces, sewage, and personal protective equipment (PPE) of staffs in isolation wards in the First Affiliated Hospital of Zhejiang University, China. METHODS: Surfaces of objects were routinely wiped with 1000mg/L chlorine containing disinfectant. Air and sewage disinfection was proceeded routinely and strictly. Hospital environmental surfaces and PPE of staffs in isolation wards were sampled using swabs. The sewage from various inlet and outlets were sampled. The respiratory and stool specimens of patients were collected. The respiratory specimens of staffs in the isolation wards were also sampled once a week. Quantitative real-time reverse transcription PCR (qRT-PCR) methods were used to confirm the existence of SARS-Cov-2 RNA. Viral culture was done for the samples positive for SARS-Cov-2 RNA. RESULTS: During the study period, 33 laboratory-confirmed patients were hospitalized in isolation wards in the hospital. None of SARS-Cov-2 RNA was detected among the 36 objects surface samples and 9 staffs PPE samples in isolation wards. Though the 3 sewage samples from the inlet of preprocessing disinfection pool were positive for SARS-CoV-2 RNA and the sample from the outlet of preprocessing disinfection pool was weakly positive, the sewage sample from the outlet of the last disinfection pool was negative. All of the 5 sewage samples from various points were negative by viral culture of SARS-Cov-2. None of the respiratory specimens of staffs in the isolation wards were positive. CONCLUSIONS: Though SARS-Cov-2 RNA of the sewage samples were positive from inlets of the sewage disinfection pool and negative from the outlet of the last sewage disinfection pool, no viable virus was detected by culture. The monitoring data in this study suggested that the strict disinfection and hand hygiene could decrease the hospital-associated COVID-19 infection risk of the staffs in isolation wards.

57 Fe Mössbauer Spectroscopy Characterization of Electrocatalysts.

This work addresses the importance of Mössbauer spectroscopy for the characterization of iron-containing electrocatalysts. The most important aspects of electrocatalysis and Mössbauer spectroscopy are summarized. Next, Fe-N-C catalysts and important conclusions made by this technique on preparation, active site identification and degradation are summarized. Furthermore, recent highlights derived for other iron-containing electrocatalysts are summarized.

Protective effect of albumin on lungs injury in traumatic/hemorrhagic shock rats.

OBJECTIVE: To determine the effect of albumin administration on lung injury in traumatic/hemorrhagic shock (T/HS) rats. METHODS: Forty-eight adult Sprague-Dawley rats were divided into three groups randomly (n=16 in each group): Group A, Group B, Group C. In Group A, rats underwent laparotomy without shock. In Group B, rats undergoing T/HS were resuscitated with their blood plus lactated Ringer's (twice the volume of shed blood). In Group C, rats undergoing T/HS were resuscitated with their shed blood plus additional 3 ml of 5% human albumin. The expression of polymorphonuclear neutrophils CD18/CD11b in jugular vein blood was evaluated. The main lung injury indexes (the activity of myeloperoxidase and lung injury score) were measured. RESULTS: Significant differences of the expression of CD18/11b and the severity degree of lung injury were founded between the three groups. (P<0.05). The expression of CD18/CD11b and the main lung injury indexes in Group B and Group C increased significantly compared with those in Group A (P<0.05). At the same time, the expression of CD18/CD11b and the main lung injury indexes in Group C decreased dramatically, compared those in Group B (P<0.05). CONCLUSIONS: The infusion of albumin during resuscitation period can protect lungs from injury and decrease the expression of CD18/CD11b in T/HS rats.