Effect of Fusion Boundary Microstructure on Flow-Accelerated Corrosion Cracking.

Flow-accelerated corrosion (FAC) preferentially attacks the downstream heat-affected zone of the root-pass weld in steam pipe systems. A detailed characterization identifies the fusion boundary as the initiation location for the attack. Alloying elements are found depleted along the weld fusion boundary, and multiple welding thermal cycles and repetitive austenite-to-ferrite phase transformations result in an increased proportion of grains with Goss {110}<001> texture along the fusion boundary. The synergistic effects of chemical segregation and the Schmid factor may contribute to the preferential initiation of FAC cracks along the root weld fusion boundary, making it the weakest link for FAC attack in steam pipe girth welds.

[Application of high flow nasal canula in patients with pulmonary edema caused by seawater drowning].

OBJECTIVE: To investigate the therapeutic effect of high-flow nasal cannula oxygen therapy (HFNC) and non-invasive positive pressure ventilation (NPPV) on patients with pulmonary edema caused by seawater drowning. METHODS: A retrospective analysis method was used. Based on the Utstein database of emergency drowning in the First Hospital of Qinhuangdao, the clinical data of patients with seawater drowning pulmonary edema admitted to the emergency medicine department of the First Hospital of Qinhuangdao from January 1, 2019 to December 31, 2022 were collected. The patients were divided into NPPV group and HFNC group according to different ventilation methods. The general data, endotracheal intubation rate in 7 days, arterial blood gas analysis indexes [arterial partial pressure of oxygen (PaO2), arterial partial pressure of carbon dioxide (PaCO2), arterial oxygen saturation (SaO2)] and hemodynamic indexes (systolic blood pressure, diastolic blood pressure, mean arterial pressure, heart rate, blood lactic acid) before and after treatment, length of stay in intensive care unit (ICU), oxygen therapy comfort of the two groups were compared. RESULTS: A total of 54 patients were enrolled, including 21 patients in the NPPV group and 33 patients in the HFNC group. There were no significant differences in gender, age, state of consciousness and other general information between the two groups. Compared with NPPV group, the rate of endotracheal intubation in HFNC group within 7 days was significantly lower [24.2% (8/33) vs. 33.3% (7/21), P < 0.05]. Before treatment, there were no significant differences in arterial blood gas analysis and hemodynamics between the two groups. After treatment, the above indexes in both groups were significantly improved compared with those before treatment, and PaO2, SaO2, systolic blood pressure, diastolic blood pressure and mean arterial pressure in HFNC group were significantly higher than those in NPPV group [PaO2 (mmHg, 1 mmHg≈0.133kPa): 93.56±6.37 vs. 82.14±6.25, SaO2: 1.02±0.09 vs. 0.95±0.11, systolic blood pressure (mmHg): 117.37±8.43 vs. 110.42±8.38, diastolic blood pressure (mmHg): 79.43±7.61 vs. 72.21±4.32, mean arterial pressure (mmHg): 92.34±6.32 vs. 85.12±5.38], PaCO2, heart rate and blood lactic acid were significantly lower than those in NPPV group [PaCO2 (mmHg) : 34.26±5.63 vs. 37.24±6.22, heart rate (times/min): 73.38±7.56 vs. 86.25±5.41, blood lactic acid (mmol/L): 1.38±0.36 vs. 2.25±1.14], and the differences were statistically significant (all P < 0.05). In addition, the length of ICU stay in HFNC group was significantly shorter than that in NPPV group (days: 13.30±2.38 vs. 16.27±4.26), and the comfort rate of oxygen therapy was significantly higher than that in NPPV group [66.7% (22/33) vs. 42.8% (9/21)], with statistical significance (all P < 0.05). CONCLUSIONS: HFNC can improve the oxygenation of patients with pulmonary edema caused by seawater drowning, improve hemodynamics, reduce the rate of tracheal intubation, shorten the length of ICU stay, and improve the comfort of oxygen therapy, which has certain clinical application value.

[Establishment and evaluation of a predictive model for early neurological deterioration after intravenous thrombolysis in acute ischemic stroke based on machine learning].

OBJECTIVE: To establish a machine learning model to predict the risk of early neurological deterioration (END) based on the clinical and laboratory data of patients with acute ischemic stroke (AIS) before intravenous thrombolysis. METHODS: The clinical data of AIS patients who received intravenous thrombolytic with recombinant tissue plasminogen activator (rt-PA) at the Stroke Center of the First Hospital of Qinhuangdao City from January 2019 to July 2022 were retrospectively analyzed. Patients were divided into END group and non-END group according to whether END appeared after intravenous thrombolytic. Clinical data of patients at admission were collected, including demographic characteristics, clinical evaluation, comorbidification, drug use history, laboratory tests, etc. Univariate and multivariate Logistic regression analysis were performed to screen out the independent predictors of the END of AIS patients after intravenous thrombolytic. The study subjects were randomly divided into a training set and a test set in a 7 : 3 ratio. Four machine learning prediction models, including Logistic regression (LR), K-nearest neighbor (KNN), support vector machine (SVM) and random forest (RF), were established based on independent predictors. The receiver operator characteristic curve (ROC curve) was used to evaluate the predictive ability of each model in END. RESULTS: A total of 704 patients were enrolled, of whom 99 were identified as END and 605 as non-END. Univariate and multivariate Logistic regression analysis was used to screen out the National Institutes of Health stroke scale [NIHSS, odds ratio (OR) = 1.049, 95% confidence interval (95%CI) was 1.015-1.082, P = 0.004], systolic blood pressure (OR = 1.013, 95%CI was 1.004-1.022, P = 0.004), lymphocyte percentage (LYM%, OR = 0.903, 95%CI was 0.853-0.953, P < 0.001), platelet to lymphocyte ratio (PLR, OR = 1.007, 95%CI was 1.002-1.014, P = 0.013) were the independent predictors of END in AIS patients after intravenous thrombolysis. The area under the curve (AUC) of LR, KNN, SVM, and RF machine learning models in the test dataset were 0.789 (95%CI was 0.675-0.902), 0.797 (95%CI was 0.685-0.910), 0.851 (95%CI was 0.751-0.952) and 0.809 (95%CI was 0.699-0.919), respectively. The RF model had the highest sensitivity (95.7%). The accuracy (0.736), specificity (72.0%) and AUC of SVM model were the highest, and its overall prediction ability was better than the other three models. CONCLUSIONS: Machine learning models have a potential role in early predicting the risk of END after intravenous thrombolysis in AIS patients, and can provide help in clinical decision-making for intravenous thrombolysis.

Serum metabolomics-based heterogeneities and screening strategy for metabolic dysfunction-associated fatty liver disease (MAFLD).

BACKGROUND AND AIMS: Metabolic dysfunction-associated fatty liver disease (MAFLD) brings heavy clinical and economic burdens to society, while understandings on heterogeneities are limited. MATERIALS AND METHODS: We conducted a serum metabolomics study to reveal the metabolic heterogeneities and develop a diagnostic strategy for MAFLD using a discovery set consisting of 122 biopsy-proven MAFLD patients [lean (n = 12), overweight (n = 20), obese (n = 74), type 2 diabetes mellitus (T2DM, n = 16)] and 35 controls, and a validation set containing 60 biopsy-proven MAFLD patients (20 lean, 20 obese and 20 T2DM) and 20 controls. RESULTS: Mitochondrial dysfunction, destructed phospholipids homeostasis, and folate deficiency were most severe in MAFLD concurrent T2DM patients. Formiminoglutamate, sphinganine and sphingosine correlated positively with HbA1c, while glycoursodeoxycholicacidsulfate correlated positively with AST. Additionally, the linear discriminant analysis (LDA) model using metabolites 5-hydroxyhexanoate, ribitol and formiminoglutamate demonstrated pretty good performance in screening for MAFLD patients, with AUC for validation samples being 0.94 (CI: 0.88-1.0). For easier clinical applications, an M-index based on the three metabolites was further designed. CONCLUSION: Our study supports that MAFLD concurrent T2DM patients deserve particular attentions in clinical follow-up, and paves the way for developing more effective diagnostic options in future studies.

Gas-containing mesenteric desmoid-type fibromatosis: A case report.

RATIONALE: Desmoid-type fibromatosis is a rare benign mesenchymal neoplasm. Only 8% of desmoid-type fibromatosis develops in the abdominal cavity. The mesentery is seldom affected and gastrointestinal stromal tumors need to be considered in the differential diagnosis, particularly when imaging examination shows a tumor containing gases in the abdominal cavity. Only a few cases of gas-containing mesenteric desmoid-type fibromatosis have been reported in the literature. PATIENT CONCERNS: A 69-year-old male patient presented with hematochezia and intermittent upper abdominal pain. DIAGNOSIS: Contrast-enhanced computed tomography revealed a 3.9 × 3.6 cm gas-containing mass infiltrating the third portion of the duodenum. The tumor was heterogeneous, with cysts and air bubbles. It showed heterogeneous weak-to-mild enhancement in the solid part. Postoperative pathological examination confirmed a final diagnosis of mesenteric desmoid-type fibromatosis. INTERVENTIONS: The patient underwent surgical resection of intra-abdominal lesion. OUTCOMES: No evidence of local recurrence was noted during the 6 months of follow-up. LESSONS: Accurate preoperative diagnosis is difficult for an intra-abdominal gas-containing mass on computed tomography scan. The appearance of spiculated infiltrative margin suggests the diagnosis of desmoid-type fibromatosis. Further investigation of imaging evidence and treatment methods is necessary.

Tuning Gene Expression by Phosphate in the Methanogenic Archaeon Methanococcus maripaludis.

Methanococcus maripaludis is a rapidly growing, hydrogenotrophic, and genetically tractable methanogen with unique capabilities to convert formate and CO2 to CH4. The existence of genome-scale metabolic models and an established, robust system for both large-scale and continuous cultivation make it amenable for industrial applications. However, the lack of molecular tools for differential gene expression has hindered its application as a microbial cell factory to produce biocatalysts and biochemicals. In this study, a library of differentially regulated promoters was designed and characterized based on the pst promoter, which responds to the inorganic phosphate concentration in the growth medium. Gene expression increases by 4- to 6-fold when the medium phosphate drops to growth-limiting concentrations. Hence, this regulated system decouples growth from heterologous gene expression without the need for adding an inducer. The minimal pst promoter is identified and contains a conserved AT-rich region, a factor B recognition element, and a TATA box for phosphate-dependent regulation. Rational changes to the factor B recognition element and start codon had no significant impact on expression; however, changes to the transcription start site and the 5' untranslated region resulted in the differential protein production with regulation remaining intact. Compared to a previous expression system based upon the histone promoter, this regulated expression system resulted in significant improvements in the expression of a key methanogenic enzyme complex, methyl-coenzyme M reductase, and the potentially toxic arginine methyltransferase MmpX.

[Epidemiological analysis of jellyfish stings in coastal bathing beaches in Qinhuangdao City from 2017 to 2019].

OBJECTIVE: To analyze the distribution and composition characteristics of jellyfish stings in various coastal baths in Qinhuangdao City from 2017 to 2019, and to provide scientific basis for the prevention, control and early warning of jellyfish stings. METHODS: Statistics and analysis of the age, gender, time of stings, location of injury, first symptoms, and playing time in the sea at the time of the sting, etc. of people with jellyfish stings in various bathing beaches along the coast of Qinhuangdao from 2017 to 2019 (July to August) were conducted. RESULTS: The number of jellyfish stings in the coastal bathing beaches of Qinhuangdao City in 2017, 2018, and 2019 was decreasing year by year, with 1 890, 492, and 171 cases respectively. Among them, Qianshuiwan Bathing Beach and Dongshan Bathing Beach had more stings (60.90% and 35.08% respectively in 2017, 24.39% and 64.23% respectively in 2018, 16.96% and 16.42% respectively in 2019). There was no significant change in the gender and age distribution of jellyfish stings each year [57.99% males in 2017, with a median age of 13 (8, 31) years old; 63.21% males in 2018, with a median age of 25 (8, 29) years old; and 59.65% males in 2019, with a median age of 12 (7, 31) years old]. Stings were mainly located at the lower limbs (the proportion of lower limb injuries: 46.54% in 2018, 45.61% in 2019), followed by upper limbs (upper arm, elbow, forearm), trunk, etc. The first symptom was mainly pain (89.43% in 2018, 38.29% in 2019), followed by rash (64.43% in 2018, 59.43% in 2019), numbness, blisters, etc. Sting incidents mainly occurred from 13:00 to 17:59 (the proportion of sting incidents in this time period in 2018 and 2019 were 68.09% and 52.63%, respectively). CONCLUSIONS: Jellyfish stings in coastal baths in Qinhuangdao City are mainly distributed in Qianshuiwan Baths and Dongshan Baths. The management of these sea areas should be strengthened, and scientific publicity and medical rescue should be strengthened to prevent jellyfish stings in peak hours and related baths.

[Application of quantitative electroencephalogram monitoring in evaluating thrombolytic effect of acute cerebral infarction].

OBJECTIVE: To investigate the value of quantitative electroencephalography (qEEG) in the evaluation of thrombolytic efficacy in acute cerebral infarction. METHODS: A prospective cohort study was conducted. Ninety-four patients with acute cerebral infarction who received intravenous thrombolysis admitted to the department of emergency of Qinhuangdao First Hospital from October 2019 to September 2020 were enrolled. The relative energy values of δ, θ, α and ß waves in qEEG before and 2 hours, 24 hours and 7 days after intravenous recombinant tissue plasminogen activator (rt-PA) thrombolysis were dynamically monitored, and the power ratio index [DTABR, DTABR = (δ+θ)/(α+ß)] was calculated. The National Institutes of Health stroke scale (NIHSS) score was also recorded. The reduction of NIHSS score ≥ 3 or the disappearance of neurological symptoms were regarded as effective thrombolytic therapy. The changes of DTABR before and after thrombolysis in patients with effective and ineffective thrombolysis were analyzed, and the correlation between DTABR and NIHSS score was analyzed by Pearson method. RESULTS: A total of 94 patients were enrolled, including 64 males and 30 females. The average age was (61.71±10.11) years from 36 to 89 years old. Thrombolysis was effective in 57 cases and ineffective in 37 cases. Compared with before thrombolysis, DTABR of the effective group was significantly decreased at 2 hours, 24 hours and 7 days after thrombolysis (left cerebral infarction: 1.87±1.45, 1.59±0.88, 1.58±0.90 vs. 3.82±2.60; right cerebral infarction: 1.55±0.57, 1.41±0.50, 1.35±0.44 vs. 3.20±1.63, all P < 0.05). DTABR did not change or increase significantly at 2 hours, 24 hours and 7 days after thrombolysis compared with before thrombolysis (left cerebral infarction: 3.56±2.57, 3.48±2.19, 3.54±2.50 vs. 3.11±1.62; right cerebral infarction: 5.29±3.93, 5.33±3.94, 5.19±4.52 vs. 4.73±2.43, all P > 0.05). Pearson correlation analysis showed a significant positive correlation between DTABR and NIHSS score in patients with acute cerebral infarction (r = 0.691, P < 0.01). CONCLUSIONS: The quantitative index of qEEG, DTABR, can accurately and quickly monitor the process of thrombolysis in acute cerebral infarction, and can effectively evaluate the effect of thrombolysis in patients.

Data-Driven Models Reveal Mutant Cell Behaviors Important for Myxobacterial Aggregation.

Single mutations frequently alter several aspects of cell behavior but rarely reveal whether a particular statistically significant change is biologically significant. To determine which behavioral changes are most important for multicellular self-organization, we devised a new methodology using Myxococcus xanthus as a model system. During development, myxobacteria coordinate their movement to aggregate into spore-filled fruiting bodies. We investigate how aggregation is restored in two mutants, csgA and pilC, that cannot aggregate unless mixed with wild-type (WT) cells. To this end, we use cell tracking to follow the movement of fluorescently labeled cells in combination with data-driven agent-based modeling. The results indicate that just like WT cells, both mutants bias their movement toward aggregates and reduce motility inside aggregates. However, several aspects of mutant behavior remain uncorrected by WT, demonstrating that perfect recreation of WT behavior is unnecessary. In fact, synergies between errant behaviors can make aggregation robust.IMPORTANCE Self-organization into spatial patterns is evident in many multicellular phenomena. Even for the best-studied systems, our ability to dissect the mechanisms driving coordinated cell movement is limited. While genetic approaches can identify mutations perturbing multicellular patterns, the diverse nature of the signaling cues coupled to significant heterogeneity of individual cell behavior impedes our ability to mechanistically connect genes with phenotype. Small differences in the behaviors of mutant strains could be irrelevant or could sometimes lead to large differences in the emergent patterns. Here, we investigate rescue of multicellular aggregation in two mutant strains of Myxococcus xanthus mixed with wild-type cells. The results demonstrate how careful quantification of cell behavior coupled to data-driven modeling can identify specific motility features responsible for cell aggregation and thereby reveal important synergies and compensatory mechanisms. Notably, mutant cells do not need to precisely recreate wild-type behaviors to achieve complete aggregation.

Posttranslational Methylation of Arginine in Methyl Coenzyme M Reductase Has a Profound Impact on both Methanogenesis and Growth of Methanococcus maripaludis.

Catalyzing the key step for anaerobic production and/or oxidation of methane and likely other short-chain alkanes, methyl coenzyme M reductase (Mcr) and its homologs play a key role in the global carbon cycle. The McrA subunit possesses up to five conserved posttranslational modifications (PTMs) at its active site. It was previously suggested that methanogenesis marker protein 10 (Mmp10) could play an important role in methanogenesis. To systematically examine its physiological role, mmpX (locus tag MMP1554), the gene encoding Mmp10 in Methanococcus maripaludis, was deleted with a new genetic tool, resulting in the complete loss of the 5-C-(S)-methylarginine PTM of residue 275 in the McrA subunit. When the ΔmmpX mutant was complemented with the wild-type gene expressed by either a strong or a weak promoter, methylation was fully restored. Compared to the parental strain, maximal rates of methane formation by whole cells were reduced by 40 to 60% in the ΔmmpX mutant. The reduction in activity was fully reversed by the complement with the strong promoter. Site-directed mutagenesis of mmpX resulted in a differential loss of arginine methylation among the mutants in vivo, suggesting that activities of Mmp10 directly modulated methylation. R275 was present in a highly conserved PXRR275(A/S)R(G/A) signature sequence in McrAs. The only other protein in M. maripaludis containing a similar sequence was not methylated, suggesting that Mmp10 is specific for McrA. In conclusion, Mmp10 modulates the methyl-Arg PTM on McrA in a highly specific manner, which has a profound impact on Mcr activity.IMPORTANCE Mcr is the key enzyme in methanogenesis and a promising candidate for bioengineering the conversion of methane to liquid fuel. Our knowledge of Mcr is still limited. In terms of complexity, uniqueness, and environmental importance, Mcr is more comparable to photosynthetic reaction centers than conventional enzymes. PTMs have long been hypothesized to play key roles in modulating Mcr activity. Here, we directly link the mmpX gene to the arginine PTM of Mcr, demonstrate its association with methanogenesis activity, and offer insights into its substrate specificity and putative cofactor binding sites. This is also the first time that a PTM of McrA has been shown to have a substantial impact on both methanogenesis and growth in the absence of additional stressors.

The Nbp35/ApbC homolog acts as a nonessential [4Fe-4S] transfer protein in methanogenic archaea.

The nucleotide binding protein 35 (Nbp35)/cytosolic Fe-S cluster deficient 1 (Cfd1)/alternative pyrimidine biosynthetic protein C (ApbC) protein homologs have been identified in all three domains of life. In eukaryotes, the Nbp35/Cfd1 heterocomplex is an essential Fe-S cluster assembly scaffold required for the maturation of Fe-S proteins in the cytosol and nucleus, whereas the bacterial ApbC is an Fe-S cluster transfer protein only involved in the maturation of a specific target protein. Here, we show that the Nbp35/ApbC homolog MMP0704 purified from its native archaeal host Methanococcus maripaludis contains a [4Fe-4S] cluster that can be transferred to a [4Fe-4S] apoprotein. Deletion of mmp0704 from M. maripaludis does not cause growth deficiency under our tested conditions. Our data indicate that Nbp35/ApbC is a nonessential [4Fe-4S] cluster transfer protein in methanogenic archaea.

[Improvement of neurological function and stress in patients with acute massive cerebral infarction by mild hypothermia: a prospective randomized controlled study].

OBJECTIVE: To study the effect of mild hypothermiaon neurological function and oxidative stress in patients with acute massive cerebral infarction. METHODS: Sixty patients with acute massive cerebral infarction (within 12 hours of onset, the age < 70 years old) admitted to the First Hospital of Qinhuangdao from August 2017 to August 2018 were enrolled. Patients were divided into control group and observation group according to random number table method, with 30 patients in each group. The control group was given conventional treatment such as lowering intracranial pressure, anticoagulation, improving microcirculation, neurotrophy and anti-stress ulcer, while the observation group was received mild hypothermia (after 72 hours of treatment at 32-35 centigrade, it increased about 1 centigrade every 6 hours until the normal temperature). The neurological impairment (the National Institutes of Health Stroke Scale, NIHSS), motor function (Fugl-Meyer score), daily living ability (Bathel index) and coma degree (Glasgow coma scale, GCS) were observed before treatment and 72 hours after treatment. The levels of plasma malondialdehyde (MDA), superoxide dismutase (SOD) and advanced oxidative protein products (AOPP) were measured at same time. After 72 hours of treatment, the therapeutic effect was judged according to the NIHSS score. RESULTS: There was no significant difference in NIHSS score, Fugl-Meyer score, Bathel index and GCS scores, and the levels of plasma MDA, SOD and AOPP between two groups before treatment. Compared with before treatment, NIHSS score and plasma MDA and AOPP levels in the two groups were significantly decreased after treatment, while Fugl-Meyer score, Bathel index, GCS score and plasma SOD activity were significantly increased; and the change of observation group was more significant than those of control group [NIHSS score: 9.78±3.24 vs. 13.44±2.63, MDA (mmol/L): 8.70±2.79 vs. 10.50±3.81, AOPP (µmol/L): 51.10±17.81 vs. 72.60±18.71, Fugl-Meyer score: 55.68±8.38 vs. 46.25±3.92, Bathel index: 66.63±11.25 vs. 56.71±10.81, GCS score: 13.78±1.31 vs. 10.49±1.03, SOD (kU/L): 134.70±29.87 vs. 104.60±25.75, all P < 0.05]. The total effective rate of the observation group was significantly higher than that of the control group [93.3% (28/30) vs. 86.7% (26/30), χ2 = 6.119, P = 0.020]. CONCLUSIONS: Mild hypothermia was effective in treating acute massive cerebral infarction. It could significantly improve the neurological function and oxidative stress of patients, improve the quality of life, and was safe and reliable.

Regeneration and characterization of LiNi0.8Co0.15Al0.05O2 cathode material from spent power lithium-ion batteries.

The use and scrap of lithium ion batteries, especially power lithium ion batteries in China, are increasing every year. Regeneration of spent battery materials is not only important for environmental protection and resource saving, but also for the production of high value-added materials. In this research, spent power lithium-ion battery cathode material LiNi1-xCoxO2 was acid-leached and a polymetallic leaching solution containing Li, Ni, Co, Al and Cu was obtained. Cu was extracted from the leachate by using CP-150 (2-hydroxy-5-nonyl salicylaldehyde oxime). The optimal conditions were found to be organic: aqueous phase ratio (O/A) = 2:1, extraction agent concentration of 30%, and pH = 3. The precursor was prepared by coprecipitation of the leachate after Cu removal. Then, cathode material of lithium nickel cobalt aluminate LiNi0.8Co0.15Al0.05O2 was synthesized under the optimal conditions of n (precursor): n (lithium carbonate) = 1:1.1, calcination temperature of 800 °C for 15 h. The regenerated LiNi0.8Co0.15Al0.05O2 product prepared under the optimized conditions was in a pure phase with a layered structure and a smooth surface morphology. The first charge specific capacity was 248.7 mAh/g, and the discharge specific capacity was 162 mAh/g. The interfacial impedance was 119 Ω. The 50th-cycle discharge specific capacity was 149.1 mAh/g, and the capacity retention rate was high as 92%. Therefore, the regenerated cathode material exhibited good performance.

[Mild hypothermia regulates aquaporin 4 expression in brain tissue of rats with cardiopulmonary resuscitation and reduces brain edema through p38 mitogen-activated protein kinase signaling pathway].

OBJECTIVE: To investigate the role of p38 mitogen-activated protein kinase (p38MAPK) signaling pathway in the expression of aquaporin 4 (AQP4) in brain tissue of rats with cardiopulmonary resuscitation (CPR) during mild hypothermia. METHODS: Forty-eight healthy male Sprague-Dawley (SD) rats were divided into sham operation group, normal temperature group and mild hypothermia group according to random number table method, with 16 in each group. The rat model of cardiac arrest-cardiopulmonary resuscitation (CPR) was established by asphyxia method. The sham operation group only experienced venous catheterization and tracheal intubation. The mild hypothermia group was treated with hypothermia 0.5 hours after restore of spontaneous circulation (ROSC, maintaining esophageal temperature at 32-34 centigrade); the normal temperature group was treated at room temperature after ROSC (maintaining esophageal temperature at 36-38 centigrade). Brain tissue was harvested at 6 hours after ROSC, and histopathological changes were observed by hematoxylin-eosin (HE) staining. The water content of brain tissue was determined by dry-wet specific gravity method. The protein expressions of phosphorylation of p38 mitogen-activated protein kinase (p-p38MAPK), p38MAPK and AQP4 in brain tissue were determined by Western Blot. RESULTS: Compared with the sham operation group, the nerve cells in the normal temperature group were reduced in size, cytoplasmic loosening, nuclear pyknosis, and in apoptotic body formation, water content of brain tissue was significantly increased [(83.64±2.53)% vs. (77.95±0.94)%, P < 0.05], the protein expressions of p-p38MAPK, p38MAPK, AQP4 were significantly increased (p38MAPK/ß-actin: 1.010±0.217 vs. 0.427±0.090, p-p38MAPK/p38MAPK: 0.451±0.172 vs. 0.191±0.141, AQP4/ß-actin: 3.129±0.754 vs. 1.598±0.464, all P < 0.05). Compared with the normal temperature group, the degree of necrosis of nerve cells in the mild hypothermia group was reduced, the water content of brain tissue was significantly decreased [(80.49±2.05)% vs. (83.64±2.53)%, P < 0.05], the protein expression of p38MAPK, p-p38MAPK and AQP4 in brain tissue were significantly decreased (p38MAPK/ß-actin: 0.590±0.162 vs. 1.010±0.217, p-p38MAPK/p38MAPK: 0.298±0.076 vs. 0.451±0.172, AQP4/ß-actin: 2.061±0.340 vs. 3.129±0.754, all P < 0.05). CONCLUSIONS: Mild hypothermia may regulate the expression of AQP4 in brain tissue of CPR rats through p38MAPK signaling pathway, and reduce brain edema, thereby exerting brain protection.

Transplanting the pathway engineering toolbox to methanogens.

Biological methanogenesis evolved early in Earth's history and was likely already a major process by 3.5 Ga. Modern methanogenesis is now a key process in virtually all anaerobic microbial communities, such as marine and lake sediments, wetland and rice soils, and human and cattle digestive tracts. Owing to their long evolution and extensive adaptations to various habitats, methanogens possess enormous metabolic and physiological diversity. Not only does this diversity offers unique opportunities for biotechnology applications, but also reveals their direct impact on the environment, agriculture, and human and animal health. These efforts are facilitated by an advanced genetic toolbox, emerging new molecular tools, and systems-level modelling for methanogens. Further developments and convergence of these technical advancements provide new opportunities for bioengineering methanogens.

Methanogenesis.

Methanogenesis is an anaerobic respiration that generates methane as the final product of metabolism. In aerobic respiration, organic matter such as glucose is oxidized to CO2, and O2 is reduced to H2O. In contrast, during hydrogenotrophic methanogenesis, H2 is oxidized to H+, and CO2 is reduced to CH4. Although similar in principle to other types of respiration, methanogenesis has some distinctive features: the energy yield is very low, ≤1 ATP per methane generated, and only methanogens - organisms capable of this specialized metabolism - carry out biological methane production. Methanogens, like the process they catalyze, are similarly distinctive. Methanogens are comprised exclusively of archaea. They are obligate methane producers, that is, they do not grow using fermentation or alternative electron acceptors for respiration. Finally, methanogens are strict anaerobes and do not grow in the presence of O2. Historically, methanogenesis has been viewed as a highly specialized metabolism restricted to a narrow group of prokaryotes. However, recent developments have revealed enormous diversity within the methanogens and suggest that this metabolism is one of the most ancient on earth.

[Effect of prehospital intervention based on emergency medical services on door-to-needle time of thrombolysis in acute ischemic stroke].

OBJECTIVE: To investigate the prehospital intervention based on emergency medical services (EMS) in patients with acute ischemic stroke (AIS) for door-to-needle time (DNT) with intravenous thrombolytic therapy with recombinant tissue plasminogen activator (rt-PA) impact. METHODS: 112 emergency patients receiving rt-PA intravenous thrombolysis admitted to the First Hospital of Qinhuangdao City based on EMS from June 2016 to December 2017 were enrolled. According to whether or not to receive prehospital interventions, patients were divided into prehospital intervention group (n = 42) and routine treatment group (n = 70). Both groups followed the general principles of first aid, including assessment and support of the airway, respiration, and circulation, and blood glucose, electrocardiogram, and dynamic vital signs were monitored. Based on the general principle of EMS, first-aid personnel in the prehospital intervention group screened suspected acute stroke patients requiring prehospitalization according to Los Angeles prehospital stroke screening table (LAPSS), and established fluid ways, and got blood samples to evaluate rt-PA intravenous thrombolysis and risks. Factors influenced DNT compliance were analyzed through multivariate Logistic regression, which included the education level of the patient, whether there were risk factors related to cerebrovascular disease (hypertension, coronary heart disease, diabetes), visit time, National Institute of Health stroke scale (NIHSS) score, whether received EMS intervention or not. The average DNT, DNT ≤ 60 minutes compliance rate, communication time, and decision time for thrombolysis were compared between the two groups. NIHSS score was used to evaluate the effective rate of thrombolysis for 7 days. The modified Rankin score (mRs) was used to evaluate the neurological function after 3 months of thrombolysis (a mRs score of 0-2 was defined as a good nerve function). RESULTS: Univariate analysis showed that the DNT of patients with NIHSS score > 5 was significantly shorter than those with NIHSS score ≤ 5, and DNT in patients received EMS intervention was significantly shorter than the non-receiver; but education level, visiting time, and risk factors associated with cerebrovascular disease had nothing to do with DNT. Multivariate Logistic regression analysis showed that NIHSS score and EMS intervention were the influencing factors of DNT compliance [NIHSS score: odds ratio (OR) = 0.452, 95% confidence interval (95%CI) = 0.162-1.263, P = 0.030; EMS intervention: OR = 3.077, 95%CI = 1.260-7.514, P = 0.014]. Compared with conventional treatment group, DNT of intravenous thrombolytic in prehospital intervention group was significantly shortened (minutes: 62.00±11.07 vs. 78.03±21.04), DNT ≤ 60 minutes compliance rate was significantly increased [35.7% (15/42) vs. 12.9% (9/70)], communication time [minutes: 4 (3, 6) vs. 6 (5, 9)] and decision-making thrombolytic time (minutes: 5.81±2.48 vs. 6.70±2.15) were significantly shortened, the differences were statistically significant (all P < 0.05). The 7-day effective rate in the prehospital intervention group [33.3% (14/42) vs. 14.3% (10/70), χ2 = 5.657, P = 0.017] and the 3-mouth good rate of nerve function [38.1% (16/42) vs. 14.3% (10/70), χ2 = 10.759, P = 0.001] were significantly higher than those in the conventional treatment group. CONCLUSIONS: Prehospital interventions based on EMS can shorten DNT of intravenous thrombolysis in the patients with AIS, improve treatment efficiency, and improve prognosis.

Assembly of Methyl Coenzyme M Reductase in the Methanogenic Archaeon Methanococcus maripaludis.

Methyl coenzyme M reductase (MCR) is a complex enzyme that catalyzes the final step in biological methanogenesis. To better understand its assembly, the recombinant MCR from the thermophile Methanothermococcus okinawensis (rMCRok) was expressed in the mesophile Methanococcus maripaludis The rMCRok was posttranslationally modified correctly and contained McrD and the unique nickel tetrapyrrole coenzyme F430 Subunits of the native M. maripaludis (MCRmar) were largely absent, suggesting that the recombinant enzyme was formed by an assembly of cotranscribed subunits. Strong support for this hypothesis was obtained by expressing a chimeric operon comprising the His-tagged mcrA from M. maripaludis and the mcrBDCG from M. okinawensis in M. maripaludis The His-tagged purified rMCR then contained the M. maripaludis McrA and the M. okinawensis McrBDG. The present study prompted us to form a working model for MCR assembly, which can be further tested by the heterologous expression system established here.IMPORTANCE Approximately 1.6% of the net primary production of plants, algae, and cyanobacteria are processed by biological methane production in anoxic environments. This accounts for about 74% of the total global methane production, up to 25% of which is consumed by anaerobic oxidation of methane (AOM). Methyl coenzyme M reductase (MCR) is the key enzyme in both methanogenesis and AOM. MCR is assembled as a dimer of two heterotrimers, where posttranslational modifications and F430 cofactors are embedded in the active sites. However, this complex assembly process remains unknown. Here, we established a heterologous expression system for MCR to learn how MCR is assembled.