In this study, X-ray imaging and electrochemical measurements were simultaneously performed to clarify the effects of the properties of micro-porous layers (MPLs) on the i-V performance and the ...liquid water behavior (LWB) of polymer electrolyte fuel cells (PEFCs) operating at a cell temperature of 50 ∘C and relative humidity of 80 %. To evaluate the effects of wettability, structure and thickness of MPLs, four types of MPLs were tested. The results demonstrate that LW accumulation (LWA) in the substrate part decreased in hydrophilic MPLs by a mechanism that sucks up liquid water and evaporates it. Moreover, MPLs using carbon fiber (CF) material demonstrated less LWA than those using carbon black (CB). Furthermore, the difference in MPL thickness significantly affects the cell performance and LWB, indicating that the MPL thickness optimization is necessary. These results indicates that hydrophilic MPLs effectively suppress LWA and enhance the oxygen transport.
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•The effects of hydrophilic MPLs are studied using in-situ X-ray visualization.•Hydrophilic MPL wicks liquid water from accumulated water in the substrate layer.•Carbon fiber MPL case demonstrates higher performance than carbon black MPL case.•Thicker MPL reduced liquid water accumulation compared to thinner MPL.
Purpose
This study aims to clarify the influence of the COVID-19 pandemic on cancer surgery in Gunma Prefecture.
Methods
A total of 9839 cases (1406 gastric cancer, 3569 colorectal cancer, 1614 lung ...cancer, and 3250 breast cancer) from 17 hospitals in Gunma Prefecture were investigated. We compared the number of surgical cases, proportion of cases found by screening, and cStage at the time of the first visit by month in 2020 and 2021 with those in 2019.
Results
The rate of decline in cancer surgery was 8.9% in 2020 compared with 2019 (
p
= 0.0052). Compared with the same month of 2019, in some months of 2020 and 2021, significant decreases were observed in the number of surgeries for gastric and colorectal cancer, the percentage of surgical cases detected by screening in all four cancers, and the proportion of cancers with a relatively early cStage in gastric and breast cancer.
Conclusions
The number of surgical cases of the four cancer types detected by cancer screening decreased in Gunma Prefecture owing to the influence of the COVID-19 pandemic. Furthermore, for some cancer types, the number of operations performed in patients with early-stage cancer is also decreased.
Despite the high frequency of bacteremia in acute cholangitis, the indications for blood cultures and the relationship between the incidence of bacteremia and severity of acute cholangitis have not ...been well established. This study examined the association between the 2018 Tokyo Guidelines (TG18) severity grading for acute cholangitis and incidence of bacteremia to identify the need for blood cultures among patients with acute cholangitis in each severity grade.
Patients with acute cholangitis who visited our emergency department between 2019 and 2020 were retrospectively investigated. Patients administered antibiotics within 48 h of hospital arrival, whose prothrombin time-international normalized ratios were not measured, or who were suspected of false bacteremia were excluded.
Out of the included 358 patients with acute cholangitis, blood cultures were collected from 310 (87%) patients, of which 148 (48%) were complicated with bacteremia. As the TG18 severity grading increased, the frequency of bacteremia increased (Grade I, 35% 59/171; Grade II, 59% 48/82; Grade III, 74% 42/57; P <0.001). Agreement with the TG18 diagnostic criteria (unfulfilled, suspected, or definite) was not different between patients with and without bacteremia; however, 36% (14/39) of the patients with “unfulfilled” criteria were complicated with bacteremia.
As the severity of acute cholangitis increased, the frequency of bacteremia increased; however, the incidence of bacteremia was high even in mild cases and cases that did not meet the TG18 diagnostic criteria. Blood cultures should be collected regardless of the severity of acute cholangitis for patients who visit the emergency department.
The concept of regenerating diseased myocardium by implantation of tissue-engineered heart muscle is intriguing, but convincing evidence is lacking that heart tissues can be generated at a size and ...with contractile properties that would lend considerable support to failing hearts. Here we created large (thickness/diameter, 1-4 mm/15 mm), force-generating engineered heart tissue from neonatal rat heart cells. Engineered heart tissue formed thick cardiac muscle layers when implanted on myocardial infarcts in immune-suppressed rats. When evaluated 28 d later, engineered heart tissue showed undelayed electrical coupling to the native myocardium without evidence of arrhythmia induction. Moreover, engineered heart tissue prevented further dilation, induced systolic wall thickening of infarcted myocardial segments and improved fractional area shortening of infarcted hearts compared to controls (sham operation and noncontractile constructs). Thus, our study provides evidence that large contractile cardiac tissue grafts can be constructed in vitro, can survive after implantation and can support contractile function of infarcted hearts.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Cardiac tissue engineering aims at providing heart muscle for cardiac regeneration. Here, we hypothesized that engineered heart tissue (EHT) can be improved by using mixed heart cell populations, ...culture in defined serum-free and Matrigel-free conditions, and fusion of single-unit EHTs to multi-unit heart muscle surrogates.
EHTs were constructed from native and cardiac myocyte enriched heart cell populations. The former demonstrated a superior contractile performance and developed vascular structures. Peptide growth factor-supplemented culture medium was developed to maintain contractile EHTs in a serum-free environment. Addition of triiodothyronine and insulin facilitated withdrawal of Matrigel from the EHT reconstitution mixture. Single-unit EHTs could be fused to form large multi-unit EHTs with variable geometries.
Simulating a native heart cell environment in EHTs leads to improved function and formation of primitive capillaries. The latter may constitute a preformed vascular bed in vitro and facilitate engraftment in vivo. Serum- and Matrigel-free culture conditions are expected to reduce immunogenicity of EHT. Fusion of single-unit EHT allows production of large heart muscle constructs that may eventually serve as optimized tissue grafts in cardiac regeneration in vivo.
Liquid water that accumulates inside gas diffusion layers (GDL) prevents oxygen transport and degrades the performance of polymer electrolyte fuel cells (PEFCs). Therefore, improving the drainage of ...GDL is neccesary. One factor that directly affects drainage is the wettability of GDLs. In this study, the relationship between wettability of GDL and drainage was investigated through a numerical simulation using the volume of fluid (VOF) method. The simulation incorporated condensation model to mimic the actual operation of a PEFC. As a result of the simulation, it was found that condensation occurs near the catalyst layer (CL), and that liquid water accumulation develops from the vicinity of the CL side to the channel side. Simulations for different contact angles of θ contact = 60°, 90°, 110°, and 150° were performed, and showed that the liquid water volume inside the GDL decreased in the case of higher contact angle. In addition, we found that the hydrophobicity of the GDL promotes the movement of liquid water and hastened liquid-water discharge from the GDL surface. In the case of higher contact angle, the proportion of the gas-liquid interface in the GDL and its curvature were found to increase. Furthermore, the liquid water was discharged from greater number of pores on the GDL surface.
We herein present a case of acquired hemophilia A with a normal activated partial thromboplastin (aPTT), intramuscular hematoma and cerebral hemorrhage occurring in a 73-year-old man. The patient ...visited our emergency department with gait disturbance, pain and swelling in his right leg. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed intramuscular hematoma and intracranial hemorrhage. The results of initial coagulation studies were normal, but repeated coagulation studies revealed an isolated prolongation of the aPTT. Additional laboratory tests confirmed the diagnosis of acquired hemophilia A. If the initial aPTT is normal, we should therefore repeat the aPTT and also perform other coagulation studies including a mixing study, factor VIII level and inhibitor, to investigate the underlying diseases in elderly patients with spontaneous hemorrhaging of unknown etiology.
RATIONALE:Cardiac tissue engineering should provide “realistic” in vitro heart muscle models and surrogate tissue for myocardial repair. For either application, engineered myocardium should display ...features of native myocardium, including terminal differentiation, organotypic maturation, and hypertrophic growth.
OBJECTIVE:To test the hypothesis that 3D-engineered heart tissue (EHT) culture supports (1) terminal differentiation as well as (2) organotypic assembly and maturation of immature cardiomyocytes, and (3) constitutes a methodological platform to investigate mechanisms underlying hypertrophic growth.
METHODS AND RESULTS:We generated EHTs from neonatal rat cardiomyocytes and compared morphological and molecular properties of EHT and native myocardium from fetal, neonatal, and adult rats. We made the following key observationscardiomyocytes in EHT (1) gained a high level of binucleation in the absence of notable cytokinesis, (2) regained a rod-shape and anisotropic sarcomere organization, (3) demonstrated a fetal-to-adult gene expression pattern, and (4) responded to distinct hypertrophic stimuli with concentric or eccentric hypertrophy and reexpression of fetal genes. The process of terminal differentiation and maturation (culture days 7–12) was preceded by a tissue consolidation phase (culture days 0–7) with substantial cardiomyocyte apoptosis and dynamic extracellular matrix restructuring.
CONCLUSIONS:This study documents the propensity of immature cardiomyocytes to terminally differentiate and mature in EHT in a remarkably organotypic manner. It moreover provides the rationale for the utility of the EHT technology as a methodological bridge between 2D cell culture and animal models.
Background Air leak is a common problem in pulmonary surgical procedures. In this study, we evaluated the efficacy and safety of gelatin glue (cross-linked with glutaraldehyde) in a rat model of lung ...air leak. Methods A model of pulmonary fistula was created in the rat lung with the use of a needle. The fistula was then sealed with either gelatin glue (group A), fibrin glue (group B), or fibrin glue with a polyglycolic acid sheet (group C). The seal breaking pressures were measured for each group, and the results were compared. To assess the biocompatibility of the gelatin glue, a model of lung damage was created with incision, and the gelatin glue was applied to seal the wound. Histologic analysis was then performed on the lung tissue. Results The seal breaking pressure in group A (47.88 ± 6.69 mm Hg) was significantly higher than that in group B (24.67 ± 3.24 mm Hg, p = 0.0302) or group C (28.67 ± 3.55 mm Hg, p = 0.0406). Histologically, the gelatin glue adhered firmly to the lung surface, and only localized tissue inflammation was observed. Conclusions The sealing effect of gelatin glue was superior to that of fibrin glue, with or without a polyglycolic acid sheet. In addition, the gelatin glue only caused mild inflammation of the lung and was absorbed without any adverse foreign body response. These findings suggest that gelatin glue may be a therapeutically effective biomaterial for sealing lung wounds and restoring respiratory function.
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