Probing and Interpreting the Porosity and Tortuosity Evolution of Li-O2 Cathodes on Discharge through a Combined Experimental and Theoretical Approach

Li-O₂ batteries offer a high theoretical discharge capacity due to the formation of light discharged species such as Li₂O₂, which fill the porous positive electrode. However, in practice, it is challenging to reach the theoretical capacity and completely utilize the full electrode pore volume during discharge. With the formation of discharge products, the porous medium evolves, and the porosity and tortuosity factor of the positive electrode are altered through shrinkage and clogging of pores. A pore shrinks as solid discharge products accumulate, the pore clogging when it is filled (or when access is blocked). In this study, we investigate the structural evolution of the positive electrode through a combination of experimental and computational techniques. Pulsed field gradient nuclear magnetic resonance results show that the electrode tortuosity factor changes much faster than suggested by the Bruggeman relation (an equation that empirically links the tortuosity factor to the porosity) and that the electrolyte solvent affects the tortuosity factor evolution. The latter is ascribed to the different abilities of solvents to dissolve reaction intermediates, which leads to different discharge product particle sizes: on discharging using 0.5 M LiTFSI in dimethoxyethane, the tortuosity factor increases much faster than for discharging in 0.5 M LiTFSI in tetraglyme. The correlation between a discharge product size and tortuosity factor is studied using a pore network model, which shows that larger discharge products generate more pore clogging. The Knudsen diffusion effect, where collisions of diffusing molecules with pore walls reduce the effective diffusion coefficients, is investigated using a kinetic Monte Carlo model and is found to have an insignificant impact on the effective diffusion coefficient for molecules in pores with diameters above 5 nm, i.e., most of the pores present in the materials investigated here. As a consequence, pore clogging is thought to be the main origin of tortuosity factor evolution.

Effects of propofol on proliferation and apoptosis of cardia cancer cells via MAPK/ERK signaling pathway

OBJECTIVE

To explore the influences of propofol on the proliferation and apoptosis of cardia cancer cells via mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling pathway.

PATIENTS AND METHODS

A total of 65 surgical resection specimens of cardia cancer were selected as research objects and divided into control group and with low (12.5 μmol/L), medium (25 μmol/L), and high (50 μmol/L) propofol concentration groups. The apoptosis of cancer cells, ERK1/2 phosphorylation level, expressions of Caspase-3, B-cell lymphoma-2 (Bcl-2), and Bcl-2 associated X protein (Bax) in each group were detected.

RESULTS

Propofol in different concentrations could all effectively inhibit the proliferation of cardia cancer cells in a dose-dependent manner. Different concentrations of propofol promoted the apoptosis of cardia cancer cells, and the apoptosis rate constantly increased with the rising concentration of propofol (p<0.05). Propofol could repress the expression of Bcl-2 and up-regulate the expression levels of Caspase-3, Bax, and phosphorylated ERK1/2.

CONCLUSIONS

Propofol can inhibit the proliferation and induce the apoptosis of cardia cancer cells, and the action mechanism may be correlated with the inhibition on the MAPK/ERK signaling pathway.

Suppression of myocardial HIF-1 by pubertal insulin resistance compromises metabolic adaptation and impairs cardiac function in patients with cyanotic congenital heart disease

Background

Cyanotic congenital heart disease (CCHD) is a complex pathophysiological condition involving systemic chronic hypoxia (CH). A proportion of CCHD patients are unoperated due to various reasons. These patients remain CH all their lives and are at increased risk of heart failure as they age. Hypoxia activates cellular metabolic adaptation to balance energy demands by accumulation of hypoxia-inducible factor 1α (HIF-1α).

Purpose

The aim of this study was to determine the effect of CH on cardiac metabolism and function in CCHD patients and how it relates with age. The mechanistic role of HIF-1α in this process was investigated and potential therapeutic targets were explored.

Methods

CCHD patients (n=20) were evaluated for cardiac metabolism and function by positron-emission tomography/computed tomography and magnetic resonance imaging. Heart tissues collected during surgical intervention were subjected to metabolomic and protein analyses. CH rodent models were generated to enable continuous observation of changes in cardiac metabolism and function. The role of HIF-1α in cardiac metabolic adaptation to CH was investigated using genetically modified animals and isotope-labeled metabolomic-pathway tracing studies.

Results

Prepubertal CCHD patients had glucose-dominant cardiac metabolism and normal cardiac function. By comparison, among patients who had entered puberty, the level of myocardial glucose uptake and glycolytic intermediates were significantly lower, but fatty acids were significantly higher, along with decreased left ventricular ejection fraction. These clinical phenotypes were replicated in CH rodent models. In patients and animals with CH, myocardial HIF-1α was upregulated prior to puberty, but was significantly downregulated during puberty. In cardiomyocyte-specific Hif-1α-knockout mice, CH failed to initiate the switch of myocardial substrates from fatty acids to glucose, leading to inhibition of ATP production and impairment of cardiac function. Increased insulin resistance (IR) suppressed myocardial HIF-1α and was responsible for cardiac metabolic maladaptation under CH during puberty. Pioglitazone significantly reduced myocardial IR, restored glucose metabolism, and improved cardiac function in pubertal animals.

Conclusions

In CCHD patients, maladaptation of cardiac metabolism occurred during puberty, impairing cardiac function. HIF-1α was identified as the key regulator of cardiac metabolic adaptation under CH but its expression was suppressed by pubertal IR. The use of pioglitazone during puberty might help improve cardiac function in these patients.

Metabolic maladaptation in CCHD patients

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): National Natural Science Foundation of China (81525002, 31971048) and Shanghai Outstanding Medical Academic Leader

Multiyear in-situ L-band microwave radiometry of land surface processes on the Tibetan Plateau

We report a unique multiyear L-band microwave radiometry dataset collected at the Maqu site on the eastern Tibetan Plateau and demonstrate its utilities in advancing our understandings of microwave observations of land surface processes. The presented dataset contains measurements of L-band brightness temperature by an ELBARA-III microwave radiometer in horizontal and vertical polarization, profile soil moisture and soil temperature, turbulent heat fluxes, and meteorological data from the beginning of 2016 till August 2019, while the experiment is still continuing. Auxiliary vegetation and soil texture information collected in dedicated campaigns are also reported. This dataset can be used to validate the Soil Moisture and Ocean Salinity (SMOS) and Soil Moisture Active Passive (SMAP) satellite based observations and retrievals, verify radiative transfer model assumptions and validate land surface model and reanalysis outputs, retrieve soil properties, as well as to quantify land-atmosphere exchanges of energy, water and carbon and help to reduce discrepancies and uncertainties in current Earth System Models (ESM) parameterizations. Measurement cases in winter, pre-monsoon, monsoon and post-monsoon periods are presented.

[Study of relationship between dietary patterns and precocious puberty of school-age girls in Shenzhen]

Objective: To explore the daily dietary behaviors of girls under precocious puberty and provide targeted measures for the prevention of precocious puberty. Methods: A case control study was conducted in a hospital in Shenzhen between September 2016 and December 2018. Girls with diagnosed precocious puberty were selected as case group. A 1∶1 matching was conducted. The control group was from 26 primary schools in Shenzhen. Dietary survey was conducted in parents, completing a self-administered questionnaire. Frequencies of 12 kinds of food intakes were investigated and dietary patterns were analyzed. Conditional logistic regression was used to analyze the relationship between dietary patterns and precocious puberty. Results: A total of 568 girls were included in the study. Among them, those aged 8-year-old accounted for highest proportion (43.8%). The median of age was same in both case group and control group (8 years-old). There was no significant difference in ethnic group between two groups (P>0.05). The medians of height, weight and BMI of case group were 135.0 cm, 30.2 kg and 16.6 kg/m(2), respectively, which were all higher than those of the control group (129.2 cm, 25.0 kg and 15.3 kg/m(2)), the differences were significant (P<0.05). There was significant difference in nutritional assessment result between two groups (P< 0.05). Three dietary patterns were defined, i.e. balanced pattern, high calorie and fat pattern and high protein diet pattern. The cumulative rate of variance contribution of the three dietary patterns was 0.541 2. The differences in the prevalence of three dietary patterns between two groups were significant (χ(2)=4.41, χ(2)=49.24, χ(2)=39.68, P<0.05 respectively). Data from the multivariate regression analysis showed that both balanced dietary pattern (OR=0.633, 95%CI: 0.504-0.769) and high protein diet pattern (OR=0.622, 95%CI: 0.498-0.776) were protective factors for precocious puberty, while high calorie and fat pattern was risk factors (OR=1.850, 95%CI: 1.461-2.342). Conclusions: Balanced dietary pattern was common in school-aged girls. High calorie and fat pattern was risk factor for precocious puberty. Children should be encouraged to develop a balanced dietary habit and increasing the intake of legumes and fish since they are beneficial to normal growth and development.

miR-137 alleviates focal cerebral ischemic injury in rats by regulating JAK1/STAT1 signaling pathway

The repairing effect and potential mechanism of miR-137 on cerebral ischemic injury in rats was investigated. The volume of cerebral infarction and calculated brain water content was detected by triphenyltetrazolium chloride staining. The expression of inflammatory factors was detected by enzyme-linked immunosorbent assay. The pathological damage of brain tissue was analyzed by hematoxylin and eosin and Nissl staining. The apoptosis in ischemic brain tissue was detected by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling. The levels of STAT1 and JAK1 proteins were analyzed by Western blot. The expression of miR-137 in primary hippocampal neurons was detected by reverse transcription polymerase chain reaction. miR-137 overexpression significantly improved brain damage in rats. miR-137 overexpression can reduce the expression of TNF-α, IL-1β, and IL-6. miR-137 overexpression can reduce the degree of brain tissue damage and inhibit the expression of JAK1 and STAT1 proteins. miR-137 overexpression can reduce oxygen-glucose deprivation (OGD)/R-induced cell damage, improve cell proliferation, and reduce apoptotic rate. JAK1 and STAT1 protein expression was inhibited in hippocampal neurons after OGD/R treatment after transfection with miR-137 mimic. After the addition of the Filgotinib inhibitor, the levels of JAK1 and STAT1 proteins were significantly reduced. The results suggested that miR-137 overexpression can effectively improve ischemic injury after focal cerebral ischemia and protect against by inhibiting JAK1/STAT1 pathway.

[Role of PI3K/Akt signaling pathway in ischemic rats underwent cardiac shock waves therapy]

Objective: To investigate the role of PI3K/Akt signaling pathway in ischemic rats underwent cardiac shock therapy. Methods: Adult male Sprague Dawley (SD) rats weighing 220-250 g were used to establish a heart failure model by ligation of the left anterior descending coronary artery. Rat models were defined by echocardiographic assessment at 4 weeks post operation and heart failure rats were randomly divided into 4 groups,namely heart failure group (HF group, 9 cases),heart failure+cardiac shock waves therapy group (HF+CSWT group, 9 cases),heart failure+inhibitor(HF+LY294002 group, 9 cases),heart failure+cardiac shock waves therapy group+inhibitor (HF+CSWT+LY294002 group, 9 cases),and another 9 sham-operated SD rats served as control group (sham group, 9 cases). At 8 weeks postoperation, echocardiography was used to evaluate cardiac function in each group,myocardial infarct size was measured by TTC staining,the apoptotic index of rats cardiomyocytes were detected by TUNEL method,the myocardial mRNA expression of apoptosis-related factor was detected by real-time quantitative PCR, the protein expression levels of PI3K/Akt signaling pathway and apoptosis-related pathways were detected by Western blot. Results: (1) Eight weeks after operation, left ventricular end diastolic diameter (LVEDD) and left ventricular end systolic diameter (LVESD) were significantly lower in HF+CSWT group than in HF group (all P<0.05), left ventricular ejection fraction (LVEF) and left ventricular shortening rate (LVFS) were significantly higher in HF+CSWT group than in HF group (all P<0.05),LVEF was significantly lower in the HF+ CSWT+ LY294002 group than in HF+ CSWT group (P<0.05). (2) Myocardial infarct size was significantly lower in the HF+ CSWT group than in HF group ((5.57 ± 0.51)% vs. (25.56 ± 0.56)%, P<0.05), which was significantly higher in the HF+CSWT+LY294002 group than in HF+CSWT group ((12.90±2.34)% vs. (5.57±0.51)%,P<0.05). (3) The cardiomyocyte apoptotic index was significantly lower in the HF+CSWT group than in the HF group ((30.25±6.12)% vs. (53.85±9.89)%,P<0.05), which was significantly higher in the HF+CSWT+LY294002 group than in the HF+CSWT group ((46.12±3.42)% vs.(30.25±6.12)%,P<0.05). (4) The myocardial mRNA expression of Bcl-2 was significantly higher, while myocardial mRNA Bax and Caspase-3 expression were significantly lower in HF+CSWT group than in HF group and HF+CSWT+LY294002 group (all P<0.05). (5) The expression levels of p-Akt, Bcl-2 and pro-Caspase-3 in myocardial tissue were significantly higher in the HF+CSWT group than in the HF group and HF+CSWT+LY294002 group (all P<0.05), which were significantly lower in the HF+LY294002 group than in the HF and HF+CSWT+LY294002 groups (all P<0.05). Myocardial Bax protein expression was significantly lower in the HF+CSWT group than in the HF group and the HF+CSWT+LY294002 group (all P<0.05), which was significantly higher in the HF+LY294002 group than in the HF group (P<0.05). Conclusion: CSWT improves cardiac function and inhibits cardiomyocyte apoptosis through PI3K/Akt signaling pathways in this rat HF model.

Critical roles of regulatory B and T cells in helminth parasite-induced protection against allergic airway inflammation

The prevalence of allergic asthma and incidences of helminth infections in humans are inversely correlated. Although experimental studies have established the causal relation between parasite infection and allergic asthma, the mechanism of the parasite-associated immunomodulation is not fully elucidated. Using a murine model of asthma and nematode parasite Heligmosomoides polygyrus, we investigated the roles of regulatory B cells (B_reg ) and T cells (T_reg ) in mediation of the protection against allergic asthma by parasite. H. polygyrus infection significantly suppressed ovalbumin (OVA)-induced allergic airway inflammation (AAI) evidenced by alleviated lung histopathology and reduced numbers of bronchoalveolar inflammatory cell infiltration, and induced significant responses of interleukin (IL)-10⁺ B_reg , IL-10⁺ T_reg and forkhead box protein 3 (FoxP3)⁺ T_reg in mesenteric lymph node and spleen of the mice. Adoptive transfer of IL-10⁺ B_reg and IL-10⁺ T_reg cell prevented the lung immunopathology in AAI mice. Depletion of FoxP3⁺ T_reg cells in FoxP3-diphtheria toxin (DT) receptor transgenic mice by diphtheria toxin (DT) treatment exacerbated airway inflammation in parasite-free AAI mice and partially abrogated the parasite-induced protection against AAI. IL-10⁺ B_reg cells were able to promote IL-10⁺ T_reg expansion and maintain FoxP3⁺ T_reg cell population. These two types of T_regs failed to induce CD19⁺ B cells to transform into IL-10⁺ B_reg cells. These results demonstrate that B_reg , IL-10⁺ T_reg and FoxP3⁺ T_reg cells contribute in A discrepant manner to the protection against allergic airway immunopathology by parasiteS. B_reg cell might be a key upstream regulatory cell that induces IL-10⁺ T_reg response and supports FoxP3⁺ T_reg cell population which, in turn, mediate the parasite-imposed immunosuppression of allergic airway inflammation. These results provide insight into the immunological relationship between parasite infection and allergic asthma.