A concave four-arc honeycomb with enhanced stiffness and desirable negative Poisson's effect.

The conventional star-shaped honeycomb (CSSH) structure is inherently rich in mechanical properties. Based on the CSSH structure, the Poisson's ratio and Young's modulus can be improved by adding the tip re-entrant angle (ISSH). In this paper, a new concave four-arc honeycomb (CFAH) structure is proposed by designing the straight rod as a curved rod and retaining the tip re-entrant angle from the ISSH structure. The Young's modulus, specific stiffness and Poisson's ratio of CFAH structures are derived from Castigliano's second theorem and Moore's theorem. The theoretical results show good agreement with the numerical and experimental results. The results show that the normalized effective specific stiffness and normalized effective Young's modulus of the CFAH structure are further improved by about 12.95% and 16.86%, respectively, compared with the ISSH structure, and more significant auxiliary effects are obtained. CFAH structures show good promise in aerospace, construction and other applications due to their enhanced mechanical property. Meanwhile, the present work provides guidance for the study of concave four-arc honeycomb structures.

Independent risk factors of acute kidney injury among patients receiving extracorporeal membrane oxygenation.

OBJECTIVE: Acute kidney injury (AKI) is one of the most frequent complications in patients treated with extracorporeal membrane oxygenation (ECMO) support. The aim of this study was to investigate the risk factors of AKI in patients undergoing ECMO support. METHODS: We performed a retrospective cohort study which included 84 patients treated with ECMO support at intensive care unit in the People's Hospital of Guangxi Zhuang Autonomous Region from June 2019 to December 2020. AKI was defined as per the standard definition proposed by the Kidney Disease Improving Global Outcome (KDIGO). Independent risk factors for AKI were evaluated through multivariable logistic regression analysis with stepwise backward approach. RESULTS: Among the 84 adult patients, 53.6% presented AKI within 48 h after initiation of ECMO support. Three independent risk factors of AKI were identified. The final logistic regression model included: left ventricular ejection fraction (LVEF) before ECMO initiation (OR, 0.80; 95% CI, 0.70-0.90), sequential organ failure assessment (SOFA) score before ECMO initiation (OR, 1.41; 95% CI, 1.16-1.71), and serum lactate at 24 h after ECMO initiation (OR, 1.27; 95% CI, 1.09-1.47). The area under receiver operating characteristics of the model was 0.879. CONCLUSION: Severity of underlying disease, cardiac dysfunction before ECMO initiation and the blood lactate level at 24 h after ECMO initiation were independent risk factors of AKI in patients who received ECMO support.

Dynamic and Hybrid Configurations for Extracorporeal Membrane Oxygenation: An Analysis of the Chinese Extracorporeal Life Support Registry.

Dynamic or hybrid configurations for extracorporeal membrane oxygenation (ECMO) are needed when patient physiology or clinical conditions change. Dynamic configurations included configurations converting from veno-arterial (V-A) ECMO or veno-venous (V-V) ECMO to other forms. Hybrid configurations included venous-arteriovenous (V-AV) and venovenous-arterial (VV-A) ECMO. This study retrospectively analyzed a total of 3,814 ECMO cases (3,102 adult cases) reported to the Chinese Society of Extracorporeal Life Support from January 1, 2017 to December 31, 2019. Eight-three adult patients had dynamic or hybrid ECMO configurations, whose primary diagnoses included cardiogenic shock (33.7%), cardiac arrest (6.0%), acute respiratory failure (39.8%), septic shock (9.6%), multiple trauma (3.6%), pulmonary hypertension (3.6%), and others (3.6%). Configuration changes occurred in 37 patients with the initial configuration of VA (20 to VV, 13 to V-AV, and 4 to VV-A) and 27 with the initial configuration of VV (7 to VA, and 20 to V-AV). A total of 46 (55.4%) patients received hybrid configurations of V-AV and 10 (12.0%) received VV-A. Patients with the initial configuration of VV who converted to other configurations had higher in-hospital mortality (74.1%) than other initial configurations (VA 45.9%, V-AV 76.9%, VV-A 66.7%, P = 0.021). We concluded that dynamic or hybrid ECMO configurations were used in various underlying diseases, in which V-AV was most commonly used. Patients receiving VV ECMO for respiratory support initially, who then converted to other configurations for both respiratory and circulatory support, had significantly worst outcomes among the groups studied. The initial configuration should be selected carefully after thorough assessment of patient condition.

Proteomics and metabonomics analyses of Covid-19 complications in patients with pulmonary fibrosis.

Pulmonary fibrosis is a devastating disease, and the pathogenesis of this disease is not completely clear. Here, the medical records of 85 Covid-19 cases were collected, among which fibrosis and progression of fibrosis were analyzed in detail. Next, data independent acquisition (DIA) quantification proteomics and untargeted metabolomics were used to screen disease-related signaling pathways through clustering and enrichment analysis of the differential expression of proteins and metabolites. The main imaging features were lesions located in the bilateral lower lobes and involvement in five lobes. The closed association pathways were FcγR-mediated phagocytosis, PPAR signaling, TRP-inflammatory pathways, and the urea cycle. Our results provide evidence for the detection of serum biomarkers and targeted therapy in patients with Covid-19.

Lung ultrasound score based on the BLUE-plus protocol is associated with the outcomes and oxygenation indices of intensive care unit patients.

PURPOSE: The primary objective was to demonstrate the relationship between lung ultrasound (LUS) manifestations and the outcomes of intensive care unit (ICU) patients. The secondary objective was to determine the characteristics of LUS manifestations in different subgroups of ICU patients. METHODS: This prospective multi-center cohort study was conducted in 17 ICUs. A total of 1702 patients admitted between August 31, 2017 and February 16, 2019 were included. LUS was performed according to the bedside lung ultrasound in emergency (BLUE)-plus protocol, and LUS scores were calculated. Data on the outcomes and oxygenation indices were analyzed and compared between different primary indication groups. RESULTS: The LUS scores were significantly higher for non-survivors than for survivors and were significantly different between the oxygenation index groups, with higher scores in the lower oxygenation index groups. The LUS score was an independent risk factor for the 28-day mortality. The area under the receiver operating characteristic curve was 0.663 for prediction of the 28-day mortality and 0.748 for prediction of an oxygenation index ≤100. CONCLUSIONS: The LUS score based on the BLUE-plus protocol was an independent risk factor for the 28-day mortality and was important for the prediction of an oxygenation index ≤100. An early LUS score within 24 hours of ICU admission helps predicting the outcome of ICU patients.

Effect of Focused Cardiac Ultrasound in Combination with Lung Ultrasound on Critically Ill Patients: A Multicenter Observational Study in China.

Objective Focused cardiac ultrasound (FCU) and lung ultrasound (LU) are increasingly being used in critically ill patients. This study aimed to investigate the effect of FCU in combination with LU on these patients and to determine if the timing of ultrasound examination was associated with treatment change. Methods This is a multicenter cross-sectional observational study. Consecutive patients admitted to the intensive care unit (ICU) were screened for enrollment. FCU and LU were performed within the first 24 h, and treatment change was proposed by the performer based on the ultrasound results and other clinical conditions. Results Among the 992 patients included, 502 were examined within 6 h of ICU admission (early phase group), and 490 were examined after 6 h of admission (later phase group). The early phase group and the later phase group had similar proportions of treatment change (48.8% vs. 49.0%, χ 2=0.003, P=0.956). In the multivariable analysis, admission for respiratory failure was an independent variable associated with treatment change, with an odds ratio (OR) of 2.357 [95% confidence interval (CI): 1.284-4.326, P=0.006]; the timing of examination was not associated with treatment change (OR=0.725, 95%CI: 0.407-1.291, P=0.275). Conclusions FCU in combination with LU, whether performed during the early phase or later phase, had a significant impact on the treatment of critically ill patients. Patients with respiratory failure were more likely to experience treatment change after the ultrasound examination.

Hyperbaric oxygen protects against myocardial ischemia­reperfusion injury through inhibiting mitochondria dysfunction and autophagy.

Our previous study demonstrated that hyperbaric oxygen (HBO) improves heart function predominantly through reducing oxygen stress, modulating energy metabolism and inhibiting cell apoptosis. The present study aimed to investigate the protective effects of HBO on mitochondrial function and autophagy using rats with a ligated left anterior descending artery. The cardioprotective effects of HBO were mainly evaluated using ELISA, fluorescent probes, transmission electron microscopy and reverse transcription­quantitative PCR (RT­qPCR). HBO pretreatment for 14 days (once a day) using a 0.25 MPa chamber improved mitochondrial morphology and decreased the number of autophagic vesicles, as observed using a transmission electron microscope. HBO pretreatment significantly increased the levels of ATP, ADP, energy charge and the opening of the mitochondrial permeability transition pore, but decreased the levels of AMP, cytochrome c and reactive oxygen species. Moreover, HBO pretreatment significantly increased the gene or protein expression levels of eIF4E­binding protein 1, mammalian target of rapamycin (mTOR), mitochondrial DNA, NADH dehydrogenase subunit 1, mitofusin 1 and mitofusin 2, whereas it decreased the gene or protein expression levels of autophagy­related 5 (Atg5), cytochrome c, dynamin­related protein 1 and p53, as determined using RT­qPCR or immunohistochemistry. In conclusion, HBO treatment was observed to protect cardiomyocytes during myocardial ischemia­reperfusion injury (MIRI) by preventing mitochondrial dysfunction and inhibiting autophagy. Thus, these results provide novel evidence to support the use of HBO as a potential agent for the mitigation of MIRI.

Hierarchically porous and heteroatom self-doped graphitic biomass carbon for supercapacitors.

Here we report a simple, low-cost and environment friendly method, in which Black locust seed dregs and potassium ferrate (K2FeO4) are used as starting raw materials and activation agent. The hierarchically porous carbons (BDPC) with high special surface area and abundant mesopores (SBET = 2010.1 m2 g-1 and Vmeso = 1.457 cm3 g-1) are obtained through hydrothermal treatment and chemical activation. The BDPC electrode exhibits excellent electrochemical performances by virtue of unique architecture and heteroatoms pseudocapacitance contribution. In the three-electrode system, the optimized carbon material (BDPC-2) achieves a high specific capacitance of 333 F g-1 at 1 A g-1 and displays the high rate capability (81.1% capacitance retention at 100 A g-1) in 6 M KOH electrolyte. The symmetric supercapacitor based BDPC-2 exhibits energy density as high as 26.2 Wh kg-1 (at a power density of 0.79 kW kg-1) and excellent long-term cycling stability (only 8% decrease after 10,000 cycles) in 6 M KOH.

Cardioprotective effects of combined therapy with diltiazem and superoxide dismutase on myocardial ischemia-reperfusion injury in rats.

AIMS: Our experiments were designed to study the effect of diltiazem (DIL) combined with superoxide dismutase (SOD) on myocardial ischemia-reperfusion (MIRI) injury in a rat model. MAIN METHODS: Fifty rats were randomly separated into sham, ischemia-reperfusion (IR), DIL (5mg/kg), SOD (10,000U/kg) and combinatorial therapy (DIL plus SOD) groups. MIRI was induced by ligating the left anterior descending coronary artery for 30min and then reperfusing for 60min. The cardioprotective effects of combinatorial therapy were evaluated using hemodynamics, biochemical indices, histopathology and apoptotic-related proteins and gene expression. KEY FINDINGS: Compared with the IR group, combinatorial therapy significantly improved cardiac function and decreased arrhythmia, myocardial infarction area and release of myocardial enzyme. In addition, combinatorial therapy protected the myocardial cell structure as well as markedly alleviated oxidative stress, resulting in upregulation of Bcl-2 and adenine nucleotide transporter-1 expression as well as downregulation of Bax, caspase-3 and cleaved caspase-3 expression. SIGNIFICANCE: Our results indicated that DIL combined with SOD can provide protection against MIRI in rats, and these effects may be attributed to a reduction in oxygen stress damage, attenuation of calcium overload, and inhibition of cell apoptosis.

Hyperbaric oxygen protects against myocardial reperfusion injury via the inhibition of inflammation and the modulation of autophagy.

Our previous study demonstrated that hyperbaric oxygen (HBO) preconditioning protected against myocardial ischemia reperfusion injury (MIRI) and improved myocardial infarction. However, HBO's effect on MIRI-induced inflammation and autophagy remains unclear. In this study, we investigate the potential impact and underlying mechanism of HBO preconditioning on an MIRI-induced inflammatory response and autophagy using a ligation of the left anterior descending (LAD) coronary artery rat model. Our results showed that HBO restored myocardial enzyme levels and decreased the apoptosis of cardiomyocytes, which were induced by MIRI. Moreover, HBO significantly suppressed MIRI-induced inflammatory cytokines. This effect was associated with the inhibition of the TLR4-nuclear factor kappa-B (NF-κB) pathway. Interestingly, lower expression levels of microtubule-associated protein 1 light chain 3B (LC3B) and Beclin-1 were observed in the HBO-treatment group. Furthermore, we observed that HBO reduced excessive autophagy by activating the mammalian target of the rapamycin (mTOR) pathway, as evidenced by higher expression levels of threonine protein kinase (Akt) and phosphorylated-mTOR. In conclusion, HBO protected cardiomocytes during MIRI by attenuating inflammation and autophagy. Our results provide a new mechanistic insight into the cardioprotective role of HBO against MIRI.