Insights into the Mechanism of Nitrobenzene Reduction to Aniline by Phosphomolybdic Acid Supported TM1 Single-Atom Catalysts.

Catalytic hydrogenation of nitrobenzene (Ph-NO2) to aniline (Ph-NH2) is a model reaction in the field of catalysis, in which the development of efficient catalysts remains a great challenge due to the lack of strategies to solve activity and selectivity problems. In this work, the mechanism of Ph-NO2 hydrogenation over Pt1 supported on phosphomolybdic acid (α-PMA) was proposed by density functional theory (DFT) calculations. The results show that the dissociation of the first and second N-O bonds is triggered by single H-induced and double H-induced mechanisms, respectively. The limiting potential of the reaction process is -0.19 V, which is the smallest potential in the field of Ph-NO2 reduction reaction to date. In the whole reaction process, the catalytic active site is the Pt atom, and polyoxometalate plays the role of an electronic sponge in the reaction. Additionally, based on experimentally confirmed Pt1/Na3PMA, the reduction capacity of Pd1/Na3PMA toward Ph-NO2 was predicted by DFT calculation. The distinctive adsorption patterns of Ph-NO2 on Pt1/Na3PMA and Pd1/Na3PMA were elucidated using the DOS diagram and fragment molecular orbital analysis. We anticipate that our theoretical calculations can provide novel perspectives for experimental researchers.

Regulating Efficient and Selective Single-atom Catalysts for Electrocatalytic CO2 Reduction.

Anchoring transition metal (TM) atoms on suitable substrates to form single-atom catalysts (SACs) is a novel approach to constructing electrocatalysts. Graphdiyne with sp-sp2 hybridized carbon atoms and uniformly distributed pores have been considered as a potential carbon material for supporting metal atoms in a variety of catalytic processes. Herein, density functional theory (DFT) calculations were performed to study the single TM atom anchoring on graphdiyne (TM1 -GDY, TM=Sc, Ti, V, Cr, Mn, Co and Cu) as the catalysts for CO2 reduction. After anchoring metal atoms on GDY, the catalytic activity of TM1 -GDY (TM=Mn, Co and Cu) for CO2 reduction reaction (CO2 RR) are significantly improved comparing with the pristine GDY. Among the studied TM1 -GDY, Cu1 -GDY shows excellent electrocatalytic activity for CO2 reduction for which the product is HCOOH and the limiting potential (UL ) is -0.16 V. Mn1 -GDY and Co1 -GDY exhibit superior catalytic selectivity for CO2 reduction to CH4 with UL of -0.62 and -0.34 V, respectively. The hydrogen evolution reaction (HER) by TM1 -GDY (TM=Mn, Co and Cu) occurs on carbon atoms, while the active sites of CO2 RR are the transition metal atoms . The present work is expected to provide a solid theoretical basis for CO2 conversion into valuable hydrocarbons.

Efficacy and safety of methylene blue in patients with vasodilatory shock: A systematic review and meta-analysis.

Background: The role of methylene blue (MB) in patients with vasodilatory shock is unclear. The purpose of this systematic review and meta-analysis was to evaluate the efficacy and safety of MB in patients with vasodilatory shock. Methods: We searched MEDLINE at PubMed, Embase, Web of Science, Cochrane, CNKI, CBM and Wanfang Medical databases for all observational and intervention studies comparing the effect of MB vs. control in vasodilatory shock patients. This study was performed in accordance with the PRISMA statement. There were no language restrictions for inclusion. Results: A total of 15 studies with 832 patients were included. Pooled data demonstrated that administration of MB along with vasopressors significantly reduced mortality [odds ratio (OR) 0.54, 95% confidence interval (CI) 0.34 to 0.85, P = 0.008; I 2 = 7%]. This benefit in mortality rate was also seen in a subgroup analysis including randomized controlled trials and quasi-randomized controlled trials. In addition, the vasopressor requirement was reduced in the MB group [mean difference (MD) -0.77, 95%CI -1.26 to -0.28, P = 0.002; I 2 = 80%]. Regarding hemodynamics, MB increased the mean arterial pressure, heart rate and peripheral vascular resistance. In respect to organ function, MB was associated with a lower incidence of renal failure, while in regards to oxygen metabolism, it was linked to reduced lactate levels. MB had no effect on the other outcomes and no serious side effects. Conclusions: Concomitant administration of MB and vasopressors improved hemodynamics, decreased vasopressor requirements, reduced lactate levels, and improved survival in patients with vasodilatory shock. However, further studies are required to confirm these findings. Systematic review registration: Identifier: CRD42021281847.

Vancomycin dosing in an obese patient with acute renal failure: A case report and review of literature.

BACKGROUND: Vancomycin is the most commonly used drug for methicillin-resistant Staphylococcus aureus. The empirical clinical doses of vancomycin based on non-obese patients may not be optimal for obese ones. CASE SUMMARY: This study reports a case of vancomycin dosing adjustment in an obese patient (body mass index 78.4 kg/m2) with necrotizing fasciitis of the scrotum and left lower extremity accompanied with acute renal failure. Dosing adjustment was performed based on literature review and factors that influence pharmacokinetic parameters are analyzed. The results of the blood drug concentration monitoring confirmed the successful application of our dosing adjustment strategy in this obese patient. Total body weight is an important consideration for vancomycin administration in obese patients, which affects the volume of distribution and clearance of vancomycin. The alterations of pharmacokinetic parameters dictate that vancomycin should be dose-adjusted when applied to obese patients. At the same time, the pathophysiological status of patients, such as renal function, which also affects the dose adjustment of the patient, should be considered. CONCLUSION: Monitoring vancomycin blood levels in obese patients is critical to help adjust the dosing regimen to ensure that vancomycin concentrations are within the effective therapeutic range and to reduce the incidence of renal injury.

Effect of goal-directed fluid therapy on renal function in critically ill patients: a systematic review and meta-analysis.

OBJECTIVE: To evaluate whether goal-directed fluid therapy (GDFT) reduces the risk of renal injury in critical illness. METHODS: MEDLINE via PubMed, EMBASE, CENTRAL and CBM was searched from inception to 13 March 2022, for studies comparing the effect of GDFT with usual care on renal function in critically ill patients. GDFT was defined as a protocolized intervention based on hemodynamic and/or oxygen delivery parameters. A fixed or random effects model was applied to calculate the pooled odds ratio (OR) based on heterogeneity through the included studies. RESULTS: A total of 28 studies with 9,019 patients were included. The pooled data showed that compared with usual care, GDFT reduced the incidence of acute kidney injury (AKI) in critical illness (OR 0.62, 95% confidence interval (CI) 0.47 to 0.80, p< 0.001). Sensitivity analysis with only low risk of bias studies showed the same result. Subgroup analyses found that GDFT was associated with a lower AKI incidence in both postoperative and medical patients. The reduction was significant in GDFT aimed at dynamic indicators. However, no significant difference was found between groups in RRT support (OR 0.88, 95% CI 0.74 to 1.05, p= 0.17). GDFT tended to increase fluid administration within the first 6 h, decrease fluid administration after 24 h, and was associated with more vasopressor requirements. CONCLUSIONS: This meta-analysis suggests that GDFT aimed at dynamic indicators may be an effective way to prevent AKI in critical illness. This may indicate a benefit from early adequate fluid resuscitation and the combined effect of vasopressors.

Afterload-related cardiac performance predicts prognosis in critical ill patients with sepsis: A prospective observational pilot study.

ABSTRACT: To investigate the usefulness of afterload-related cardiac performance (ACP) for assessing cardiac impairment and predicting prognosis in septic patients.Adult patients with sepsis in the intensive care unit were included. Cardiac output, cardiac index, cardiac power index, and ACP were calculated at the time of admission (D0) and 48-72 h after admission (D3). They were correlated with Acute Physiology and Chronic Health Evaluation II and sequential organ failure assessment scores, then the prognostic values were analyzed.A total of 41 patients with sepsis were selected. ACP showed a stronger negative correlation with Acute Physiology and Chronic Health Evaluation II and sequential organ failure assessment scores than cardiac output, cardiac index, and cardiac power index. ACP predicted 28-day mortality with an area under the curve of 0.775 and 0.976 on D0 and D3, respectively. In addition, most non-survivors had emergent cardiac impairment (ACP ≤ 80%) on D0, and cardiac function was deteriorated on D3. Survival analysis showed that the patients with a decreased ACP from D0 to D3 had the highest mortality. The decrease of ACP on D3 was an independent risk factor for mortality (hazard ratio, 11.89; P = .0028).ACP can be used to assess the severity of cardiac impairment in sepsis. Continued decline of ACP during the first 3 days strongly suggests a poor prognosis.

Influence of Powder Bed Temperature on the Microstructure and Mechanical Properties of Ti-6Al-4V Alloy Fabricated via Laser Powder Bed Fusion.

Laser powder bed fusion (LPBF) is being increasingly used in the fabrication of complex-shaped structure parts with high precision. It is easy to form martensitic microstructure in Ti-6Al-4V alloy during manufacturing. Pre-heating the powder bed can enhance the thermal field produced by cyclic laser heating during LPBF, which can tailor the microstructure and further improve the mechanical properties. In the present study, all the Ti-6Al-4V alloy samples manufactured by LPBF at different powder bed temperatures exhibit a near-full densification state, with the densification ratio of above 99.4%. When the powder bed temperature is lower than 400 °C, the specimens are composed of a single α' martensite. As the temperature elevates to higher than 400 °C, the α and ß phase precipitate at the α' martensite boundaries by the diffusion and redistribution of V element. In addition, the α/α' lath coarsening is presented with the increasing powder bed temperature. The specimens manufactured at the temperature lower than 400 °C exhibit high strength but bad ductility. Moreover, the ultimate tensile strength and yield strength reduce slightly, whereas the ductility is improved dramatically with the increasing temperature, when it is higher than 400 °C.

Transition-Metal-Modified Vanadoborate Clusters as Stable and Efficient Photocatalysts for CO2 Reduction.

Photocatalytic carbon dioxide reduction (CO2RR) is considered to be a promising sustainable and clean approach to solve environmental issues. Polyoxometalates (POMs), with advantages in fast, reversible, and stepwise multiple-electron transfer without changing their structures, have been promising catalysts in various redox reactions. However, their performance is often restricted by poor thermal or chemical stability. In this work, two transition-metal-modified vanadoborate clusters, [Co(en)2]6[V12B18O54(OH)6]·17H2O (V12B18-Co) and [Ni(en)2]6[V12B18O54(OH)6]·17H2O (V12B18-Ni), are reported for photocatalytic CO2 reduction. V12B18-Co and V12B18-Ni can preserve their structures to 200 and 250 °C, respectively, and remain stable in polar organic solvents and a wide range of pH solutions. Under visible-light irradiation, CO2 can be converted into syngas and HCOO- with V12B18-Co or V12B18-Ni as catalysts. The total amount of gaseous products and liquid products for V12B18-Co is up to 9.5 and 0.168 mmol g-1 h-1. Comparing with V12B18-Co, the yield of CO for V12B18-Ni declines by 1.8-fold, while that of HCOO- increases by 35%. The AQY of V12B18-Co and V12B18-Ni is 1.1% and 0.93%, respectively. These values are higher than most of the reported POM materials under similar conditions. The density functional theory (DFT) calculations illuminate the active site of CO2RR and the reduction mechanism. This work provides new insights into the design of stable, high-performance, and low-cost photocatalysts for CO2 reduction.

Safety evaluation and ibuprofen removal via an Alternanthera philoxeroides-based biochar.

Pharmaceutical and personal care products (PPCPs) are a representative class of emerging contaminants. This study aimed to investigate the PPCP removal performance and application safety of a biochar fabricated using the invasive plant Alternanthera philoxeroides (APBC). According to scanning electron microscopy and pore size analyses, APBC exhibited a porous structure with a specific surface area of 857.5 m2/g. A Fourier transform infrared spectroscopy analysis indicated the presence of surface functional groups, including phosphorus-containing groups, C=O, C=C, and -OH. The adsorption experiment showed that the maximum removal efficiency of ibuprofen was 97% at an initial concentration of 10 mg/L and APBC dosage of 0.8 g/L. The adsorption kinetics were fitted by the pseudo-second-order model with the highest correlation coefficient (R2 = 0.9999). The adsorption isotherms were well described by the Freundlich model (R2 = 0.9896), which indicates a dominant multilayer adsorption. The maximum adsorption capacity of APBC was 172 mg/g. A toxicity evaluation, based on Chlorella pyrenoidosa and human epidermal BEAS-2B cells, was carried out using a spectrum analysis, thiazolyl blue tetrazolium bromide assay, and flow cytometry. The results of the above showed the low cytotoxicity of APBC and demonstrated its low toxicity in potential environmental applications.

Peroxisome proliferator-activated receptor gamma participates in the acquisition of brain ischemic tolerance induced by ischemic preconditioning via glial glutamate transporter 1 in vivo and in vitro.

Glial glutamate transporter 1 (GLT-1) plays a vital role in the induction of brain ischemic tolerance (BIT) by ischemic preconditioning (IPC). However, the mechanism still needs to be further explained. The aim of this study was to investigate whether peroxisome proliferator-activated receptor gamma (PPARγ) participates in regulating GLT-1 during the acquisition of BIT induced by IPC. Initially, cerebral IPC induced BIT and enhanced PPARγ and GLT-1 expression in the CA1 hippocampus in rats. The ratio of nuclear/cytoplasmic PPARγ was also increased. At the same time, the up-regulation of PPARγ expression in astrocytes in the CA1 hippocampus was revealed by double immunofluorescence for PPARγ and glial fibrillary acidic protein. Then, the mechanism by which PPARγ regulates GLT-1 was studied in rat cortical astrocyte-neuron cocultures. We found that IPC [45 min of oxygen glucose deprivation (OGD)] protected neuronal survival after lethal OGD (4 h of OGD), which usually leads to neuronal death. The activation of PPARγ occurred earlier than the up-regulation of GLT-1 in astrocytes after IPC, as determined by western blot and immunofluorescence. Moreover, the preadministration of the PPARγ antagonist T0070907 or PPARγ siRNA significantly attenuated GLT-1 up-regulation and the neuroprotective effects induced by IPC in vitro. Finally, the effect of the PPARγ antagonist on GLT-1 expression and BIT was verified in vivo. We observed that the preadministration of T0070907 by intracerebroventricular injection dose-dependently attenuated the up-regulation of GLT-1 and BIT induced by cerebral IPC in rats. In conclusion, PPARγ participates in regulating GLT-1 during the acquisition of BIT induced by IPC. Cover Image for this issue: doi: 10.1111/jnc.14532. Open Science: This manuscript was awarded with the Open Materials Badge For more information see: https://cos.io/our-services/open-science-badges/.

The mechanism of GLT-1 mediating cerebral ischemic injury depends on the activation of p38 MAPK.

The previous studies have shown that glial glutamate transporter-1 (GLT-1) participates in cerebral ischemic injury in rats. However, the mechanism involved remains to be elucidated. This study was undertaken to investigate whether p38 MAPK was involved in regulating GLT-1 in the process. At first, it was observed that global brain ischemia for 8 min led to obvious delayed neuronal death, GLT-1 down-regulation and p-p38 MAPK up-regulation in CA1 hippocampus in rats. Then, whether p-p38 MAPK was involved in regulating GLT-1 during cerebral ischemic injury was studied in vitro. Astrocyte-neuron co-cultures exposed to oxygen and glucose deprivation (OGD) were used to mimic brain ischemia. It was observed that lethal OGD (4-h OGD) decreased GLT-1 expression and increased p-p38 MAPK expression in astrocytes. The p-p38 MAPK protein rised from 0 min to 48 h that is the end time of the observation, and the peak value was at 12 h, which was 12.45 times of the control group. Moreover, pre-administration of p38 MAPK inhibitor SB203580 or its siRNA dose-dependently increased GLT-1 expression, and meanwhile alleviated the neuronal death induced by lethal OGD. The above results indicated that p38 MAPK signaling pathway participated in regulating GLT-1 during OGD injury in vitro. Finally, back to in vivo experiment, it was found that pre-administration of SB203580 by intracerebroventricular injection dose-dependently reversed the down-regulation of GLT-1 expression and attenuated the delayed neuronal death normally induced by global brain ischemia in CA1 hippocampus in rats. Taken together, it can be concluded that the mechanism of GLT-1 mediating cerebral ischemic injury depends on the activation of p38 MAPK.

[Influence of time of initiation of continuous renal replacement therapy on prognosis of critically ill patients with acute kidney injury].

OBJECTIVE: To investigate the influence of the time of initiation of continuous renal replacement therapy (CRRT) on the survival and recovery of renal function in survivors of critically ill patients with acute kidney injury (AKI). METHODS: A retrospective analysis was performed on the data of critically ill patients with AKI, who were treated with CRRT from January 1, 2009 to June 30, 2011 in the Fourth Hospital of Hebei Medical University. According to Acute Kidney Injury Net (AKIN) classification at the beginning of CRRT, patients were stratified into AKIN 1, 2, 3 stages. The survival rate and kidney outcome in survivors were compared among these three AKIN groups. Additionally, the association among three influencing factors (duration of CRRT, CRRT dose and the filter life) and prognosis was analyzed. RESULTS: Fifty-two patients were enrolled, among them 15 were in AKIN 1 stage, 23 in AKIN 2 stage, and 14 in AKIN 3 stage (among them the number of female patients was 14, 16, 6, respectively, P=0.014). (1) Survival analysis: the 28-, 90-, and 180-day survival rate of AKIN 1, 2 and 3 stages (28 days: 53.3%, 52.2%, 61.5%; 90 days: 46.7%, 31.8%, 46.2%; 180 days: 35.7%, 22.7%, 46.2%), intensive care unit (ICU) survival rate (60.0%, 65.2%, 71.4%), and hospital survival rate (60.0%, 60.9%, 71.4%) showed no significant difference (all P>0.05). COX proportional hazards model analysis showed that the 28-day survival rate was significantly correlated with the CRRT dose [relative risk (RR)=0.922, 95% confidence interval (95%CI) 0.856-0.994, P<0.05]. (2) Outcome of renal function in survivors: no significant difference in renal function recovery was found 28, 90, 180 days among AKIN 1, 2 and 3 stages after CRRT (28 days: 75.0%, 66.7%, 75.0%; 90 days: 85.7%, 71.4%, 100.0%; 180 days: 80.0%, 60.0%, 100.0%, all P>0.05). Logistic regression analysis showed that it was correlated with none of the four influencing factors (gender, the filter life, duration of CRRT and CRRT dose). CONCLUSIONS: Our results indicated that the time of initiation of CRRT by AKIN classification has no effect on the 28-, 90-, 180-day survival rate, ICU survival rate and outcome of renal function in survivors of critically ill patients with AKI. Improving CRRT dose may improve 28-day survival rate.