Separators and Membranes for Advanced Alkaline Water Electrolysis.

Traditionally, alkaline water electrolysis (AWE) uses diaphragms to separate anode and cathode and is operated with 5-7 M KOH feed solutions. The ban of asbestos diaphragms led to the development of polymeric diaphragms, which are now the state of the art material. A promising alternative is the ion solvating membrane. Recent developments show that high conductivities can also be obtained in 1 M KOH. A third technology is based on anion exchange membranes (AEM); because these systems use 0-1 M KOH feed solutions to balance the trade-off between conductivity and the AEM's lifetime in alkaline environment, it makes sense to treat them separately as AEM WE. However, the lifetime of AEM increased strongly over the last 10 years, and some electrode-related issues like oxidation of the ionomer binder at the anode can be mitigated by using KOH feed solutions. Therefore, AWE and AEM WE may get more similar in the future, and this review focuses on the developments in polymeric diaphragms, ion solvating membranes, and AEM.

Synthesis of alkylsulfonyl and substituted benzenesulfonyl curcumin mimics as dual antagonist of L-type Ca(2+) channel and endothelin A/B2 receptor.

We synthesized a library of curcumin mimics with diverse alkylsulfonyl and substituted benzenesulfonyl modifications through a simple addition reaction of important intermediate, 1-(3-Amino-phenyl)-3-(4-hydroxy-3-methoxy-phenyl)-propenone (10), with various sulfonyl chloride reactants and then tested their vasodilatation effect on depolarization (50 mM K(+))- and endothelin-1 (ET-1)-induced basilar artery contraction. Generally, curcumin mimics with aromatic sulfonyl groups showed stronger vasodilation effect than alkyl sulfonylated curcumin mimics. Among the tested compounds, six curcumin mimics (11g, 11h, 11i, 11j, 11l, and 11s) in a depolarization-induced vasoconstriction and seven compounds (11g, 11h, 11i, 11j, 11l, 11p, and 11s) in an ET-1-induced vasoconstriction showed strong vasodilation effect. Based on their biological properties, synthetic curcumin mimics can act as dual antagonist scaffold of L-type Ca(2+) channel and endothelin A/B2 receptor in vascular smooth muscle cells. In particular, compounds 11g and 11s are promising novel drug candidates to treat hypertension related to the overexpression of L-type Ca(2+) channels and ET peptides/receptors-mediated cardiovascular diseases.

Granulocyte colony-stimulating factor minimizes negative remodeling of decellularized small diameter vascular graft conduits but not medial degeneration.

BACKGROUND: Poor endothelialization and intimal hyperplasia are major causes of small diameter vascular conduit (SDVC) failure. The present study was aimed to investigate the influence of granulocyte colony-stimulating factor (G-CSF) on inhibiting adverse remodeling of decellularized SDVCs. METHODS: Sprague-Dawley rats implanted with allograft infra renal abdominal aortic conduits were divided into 2 groups according to whether they were treated with G-CSF (+G-CSF group; n=6) or without (Decell group; n=6). The conduits were harvested at 8 weeks after surgery and examined for intimal hyperplasia, collagen deposition, and -actin-staining cells. The medial layer was also examined for signs of cellular repopulation and changes in the elastic fiber morphology. RESULTS: Intergroup comparison of the intimal composition showed relatively sparse collagen content and predominance of -actin-staining cells in the +G-CSF group. The medial layer in the 2 groups showed similar degrees of elastic fiber degeneration and wall thinning relative to the normal aortic wall. However, the enhanced staining for von Willebrand factor and CD31, along with transmission electron microscopy findings of superior cellular and ultrastructural preservation, suggested that the remodeling and endothelialization in the +G-CSF conduits were superior to those in the Decell conduits. CONCLUSIONS: This study suggests that G-CSF exerts a positive influence on inhibiting adverse vascular remodeling of decellularized vascular conduit implants. However, whether G-CSF administration may also effectuate an improved ability to preserve the medial structural integrity is unclear.

Mechanical valve replacement versus bioprosthetic valve replacement in the tricuspid valve position.

BACKGROUND: The purpose of this study was to evaluate the clinical outcomes and risk of tricuspid valve replacements and to compare bioprosthetic versus mechanical valves. METHODS: Between 1991 and 2009, 104 consecutive patients (71 women; mean age, 57 ± 10.8 years) with tricuspid valvular disease underwent mechanical TVR (mechanical group; n = 59) or bioprosthetic TVR (bioprosthesis group; n = 45). Follow-up was complete in 97.1% (n = 101) with a median duration of 49.9 months (range 0-230 months). RESULTS: Hospital mortality after mechanical TVR and bioprosthetic TVR was not different on adjusted analysis by propensity score. Ten-year actuarial survival after mechanical and bioprosthetic TVR was 83.9 ± 7.6% and 61.4 ± 9.1%, respectively (p = 0.004). However, there was also no significant difference in terms of adjusted analysis by propensity score (p = 0.084). No statistically significant difference was detected between mechanical and bioprosthetic valves in regard to event-free survival. CONCLUSIONS: Mechanical TVR is not inferior to bioprosthetic TVR in terms of occurrence of valve-related events, especially anticoagulation-related complications.

Malignant peripheral nerve sheath tumor arising from the left ventricle.

We report a case of a 32-year-old female who underwent complete excision of a malignant left ventricular peripheral nerve sheath tumor. Malignant peripheral nerve sheath tumors in the mediastinum, including the pericardium, are rare. This case report describes a malignant peripheral nerve sheath tumor arising from the left ventricular origin for which complete excision was possible.

Zirconia Toughened Alumina-Based Separator Membrane for Advanced Alkaline Water Electrolyzer.

Hydrogen is nowadays considered a favorable and attractive energy carrier fuel to replace other fuels that cause global warming problems. Water electrolysis has attracted the attention of researchers to produce green hydrogen mainly for the accumulation of renewable energy. Hydrogen can be safely used as a bridge to successfully connect the energy demand and supply divisions. An alkaline water electrolysis system owing to its low cost can efficiently use renewable energy sources on large scale. Normally organic/inorganic composite porous separator membranes have been employed as a membrane for alkaline water electrolyzers. However, the separator membranes exhibit high ionic resistance and low gas resistance values, resulting in lower efficiency and raised safety issues as well. Here, in this study, we report that zirconia toughened alumina (ZTA)-based separator membrane exhibits less ohmic resistance 0.15 Ω·cm2 and low hydrogen gas permeability 10.7 × 10-12 mol cm-1 s-1 bar-1 in 30 wt.% KOH solution, which outperforms the commercial, state-of-the-art Zirfon® PERL separator. The cell containing ZTA and advanced catalysts exhibit an excellent performance of 2.1 V at 2000 mA/cm2 at 30 wt.% KOH and 80 °C, which is comparable with PEM electrolysis. These improved results show that AWEs equipped with ZTA separators could be superior in performance to PEM electrolysis.

Left internal thoracic artery composite grafting with the right internal thoracic versus radial artery in coronary artery bypass grafting.

BACKGROUND: The aim of this study was to compare the results of all arterial multivessel coronary artery bypass grafting using the left internal thoracic artery composite bypass graft constructed with the right internal thoracic artery or radial artery. METHODS: Patients undergoing coronary artery bypass grafting with a left internal thoracic artery constructed as a composite bypass graft with either a right internal thoracic artery (n = 45; RITA group) or radial artery (n = 352; RA group) between 2003 and 2009 were included in the present study. RESULTS: The three-year patency rates for the RITA and RA groups were 91.8%± 4.3% and 78.6%± 3.4%, respectively (p = 0.12). Adjustments for covariates revealed the radial artery patency to be significantly inferior to the right internal thoracic artery graft (hazard ratio 4.35, 95% confidence interval 1.05 to 18.0; p = 0.043). Reintervention for target coronary artery occlusion was required in two patients in the RA group over a mean follow-up period of 35.5 ± 21.5 months. There were 43 deaths in the entire cohort of which 20 were cardiac. After adjustment for significant variables, the risk of all-cause mortality, cardiac death, and the composite of adverse events (death, reintervention, myocardial infarction, and stroke) were similar for the two groups (p = 0.98, 0.99, and 0.21, respectively). CONCLUSIONS: Although superior patency was observed with the right internal thoracic artery over the radial artery graft, a significant commensurate benefit in reducing the incidence of major adverse clinical outcomes was not necessarily shown.

A Feasibility Study of Photovoltaic-Electrolysis-PEM Hybrid System Integrated Into the Electric Grid System Over the Korean Peninsula.

A photovoltaic-electrolysis-PEM hybrid model was developed for a feasibility study, and simulations of several scenarios in Korea were performed. The solar irradiance was derived from the University of Arizona solar irradiance based on satellite-Korea Institute of Energy Research model which provides the satellite imagery over the Korean peninsula every 15 min. In Korea, the annual average solar irradiance is 1,310 kWh m-2 with a maximum of 1,440 kWh m-2 in 2017. Electricity load and solar irradiance information were used to test the performance model of the photovoltaic-electrolysis-PEM hybrid system for baseload and several peak load shave runs. When the baseload was set at 4200 MW, the total capacity of the Photovoltaic plants was 58.5 GWp. In contrast, the hybrid system reduced the peak load more efficiently during daytime. In particular, the capacity factor of the Proton Exchange Membrane system increased in winter because the solar irradiance is relatively weak in that season. These results provide useful insights for the development of control logic models for the PV-electrolysis-PEM system in micro-grid setups.

The Structural Effect of Electrode Mesh on Hydrogen Evolution Reaction Performance for Alkaline Water Electrolysis.

Alkaline water electrolysis (AWE) is a mature water electrolysis technology that can produce green hydrogen most economically. This is mainly attributed to the use of Ni-based materials that are easy to process and inexpensive. The nickel-based meshes with various structures such as woven mesh and expanded mesh are widely used as electrode in the AWE due to its common availability and easy fabrication. However, the morphological effect of meshes on hydrogen evolution reaction (HER) performance has not been studied. Here a new parameter to determine the structural effect of mesh on HER performance was first proposed. The key factors of the parameter were found to be the strand width, pore width and the strand surface area. The woven mesh with the ratio of pore width to strand width that converges to 1 showed the lowest the overpotential. The expanded mesh with the higher the structural surface area exhibited the lowest the overpotential. This study will help to choose an optimal structure for the mesh with the HER electrode.

Alternative energy sources for surgical treatment of atrial fibrillation in patients undergoing mitral valve surgery: microwave ablation vs cryoablation.

The study aim was to compare maze outcomes using microwave ablation or cryoablation in patients with mitral disease and atrial fibrillation (AF). Between 1999 and 2005, 340 patients underwent mitral valve surgery and concomitant maze procedure involving either microwave ablation (n=96, MW group) or cryoablation (n=244, Cryo group). Mean age at operation was 50.0±12.5 yr. Follow-up period was 46.1±28.2 months. The Cryo group showed a longer aortic clamping time than the MW group (P=0.005). There were no differences in operative mortality and morbidity rates. The unadjusted 5-yr AF free rate was 61.3±1.2% in the MW group and 79.9±3.2% in the Cryo group (P=0.089). After adjustment, the MW group only showed a tendency toward more frequent AF recurrence than the Cryo group (Hazard ration 1.66, 95% confidence interval 0.89 to 3.07). Multivariate analysis revealed that older patient age (P<0.001) and greater left atrial size (P<0.001) were independent risk factors for AF recurrence. Although the use of microwave ablation results in shorter aortic clamping time, it has a tendency toward more frequent late AF recurrence than with cryoablation.

Removal of Kirschner wire that migrated from the pelvic bone into the right ventricle of the heart.

A sixty-year-old man was admitted due to chest pain. He had a history of pelvic bone fracture fixation with Kirschner wire about 20 years earlier. On examination, we detected a Kirschner wire that had migrated into the right ventricle. Without cardiopulmonary bypass, we removed the migrating Kirschner wire via median sternotomy. The patient recovered without complications and was discharged on the 5th postoperative day.

Revascularization of the left anterior descending artery area using a single left internal thoracic artery: auto-Y composite grafting or sequential bypassing.

OBJECTIVE: To maximize the use of left internal thoracic artery in coronary artery bypass grafting, we have adopted a strategy to revascularize the left anterior descending artery area using a single skeletonized left internal thoracic artery; auto-Y composite grafting and sequential bypassing. This study evaluated graft patency and clinical outcomes after these procedures. METHODS: Between 2003 and 2009, 144 patients (112 men; age, 62.9 ± 8.9 years) underwent coronary artery bypass grafting using a single left internal thoracic artery graft to bypass the left anterior descending artery and a diagonal branch. Of them, 57 patients underwent sequential anastomosis (sequential group), and 87 underwent auto-Y composite anastomosis (auto-Y group). Graft patency was assessed using serial multidetector computed tomography. RESULTS: There were no early mortalities. During a mean follow-up duration of 66.2 ± 44.5 months, there were 8 deaths, including 2 cardiac deaths, and no cases of reintervention. The 2 groups were at similar risks of death on crude and adjusted analyses (P = .109 and .216). The 2-year patency rates for the LAD site were 98% in the sequential group and 100% in the auto-Y group (P = .195). The 2-year patency rates for the diagonal artery site were 100% in the sequential group and 92.9% in the auto-Y group (P = .038). CONCLUSIONS: Revascularization of the left anterior descending artery area using a single skeletonized left internal thoracic artery resulted in excellent clinical outcomes and graft patency using either auto-Y or sequential grafting. However, there was a higher rate of diagonal branch graft occlusion after auto-Y compared with sequential grafting.

Aortic Valve Replacement for Aortic Stenosis and Concomitant Coronary Artery Bypass: Long-term Outcomes and Predictors of Mortality.

BACKGROUND: We evaluated the surgical results and predictors of long-term survival in patients who underwent coronary artery bypass grafting (CABG) at the time of an aortic valve replacement (AVR) due to aortic stenosis. MATERIALS AND METHODS: Between January 1990 and December 2009, 183 consecutive patients underwent CABG and concomitant aortic valve replacement for aortic stenosis. The mean follow-up period was 59.8±3.3 months and follow-up was possible in 98.3% of cases. Predictors of mortality were determined by Cox regression analysis. RESULTS: There were 5 (2.7%) in-hospital deaths. Follow-up of the in-hospital survivors documented late survival rates of 91.5%, 74.8%, and 59.6% at 1, 5, and 10 postoperative years, respectively. Age (p<0.001), a glomerular filtration rate (GFR) less than 60 mL/min (p=0.006), and left ventricular (LV) mass (p<0.001) were significant predictors of mortality in the multivariate analysis. CONCLUSION: The surgical results and long-term survival of aortic valve replacement with concomitant CABG in patients with aortic stenosis and coronary artery disease were acceptable. Age, a GFR less than 60 mL/min, and LV mass were significant predictors of mortality.

Reverse Blalock-Taussig shunt facilitates the growth of the ascending aorta after hybrid palliation.

A 13-day-old baby girl with tricuspid atresia (IIc), who was prematurely born at 32 weeks and 5 days of gestation and weighed 2.2 kg, underwent bilateral pulmonary artery banding, ductal stenting, and reverse Blalock-Taussig shunt. Cardiac computerized tomography at 4 months postoperatively showed that the ascending aorta outgrew the somatic growth, presumably thanks to the forward flow through the reverse Blalock-Taussig shunt. At 6 months postoperatively, the patient underwent a successful second-stage operation.