Effects of porous carbon materials on heat storage performance of CaCl2 hydrate for low-grade thermal energy.

Thermochemical energy storage (TES) is a promising technology to overcome supply-demand mismatch in the recycling of low-grade industrial waste heat. A novel sorbent is developed for low-grade TES system by employing an ordered mesoporous carbon, CMK-3, as the matrix of CaCl2 hydrates. Expanded graphite (EG) and activated carbon (AC) as matrixes are also discussed for a comparative study. All the composites show quick kinetic within 120 °C. Salt upload ability and heat storage capacity of the composites follow the order of CMK-3/CaCl2 (2037.2 kJ kg-1, 50.4 wt%) > EG/CaCl2 (1637.6 kJ kg-1, 48.1 wt%) > AC/CaCl2 (1221.8 kJ kg-1, 46.3 wt%). CMK-3/CaCl2 show the best heat storage performance due to the ordered tubular mesostructure, which limits the deliquescence at a proper level and provided good accommodation for salt solution. The inner solution absorption presents positive thermal effect that add to total heat storage capacity, making actual heat sorption of CMK-3/CaCl2 much higher than pure chemical reaction heat. A 25-cycle sorption-desorption experiment shows excellent cycling stability of CMK-3/CaCl2. This study proves CMK-3/CaCl2 to be a promising composite for low-grade TES system below 120 °C, and provides new insights for improving energy density of the heat storage materials.

Efficacy of electrical isolation of the left atrial posterior wall depends on the existence of left atrial low-voltage zone in patients with persistent atrial fibrillation.

BACKGROUND: Modification of the low-voltage zone in the left atrium (LA-LVZ) in addition to pulmonary vein isolation (PVI) has not shown sufficient improvement in arrhythmia-free survival in patients with persistent atrial fibrillation (PerAF). Further, the effect of electrical posterior wall isolation (PWI) is controversial. We investigated the impact of existence of LA-LVZ on the outcome of patients undergoing additional PWI for PerAF. METHODS: A total of 347 patients with PerAF who underwent primary catheter ablation with LA-LVZ based strategy were retrospectively analyzed. Voltage mapping in the left atrium (LA) was performed during sinus rhythm. Additional LVZ ablation was performed in patients with LA-LVZ. The operators decided whether additional PWIs were to be performed. RESULTS: Of 347 patients, 108 had LA-LVZ. In the LVZ group, patients with additional PWI (N = 70) had higher rates of freedom from tachyarrhythmia recurrence than those without (77.1% vs. 42.1%, p < 0.001). Furthermore, even when patients were limited to those with LA-LVZ in areas other than the posterior wall (N = 85), PWI had higher success rates (80.9% vs. 42.1%, p < 0.001). In contrast, in patients without LVZ (N = 239), there was no significant difference in the rate of successful outcome between those with and without PWI (81.3% vs. 88.1%, p = 0.112). On the other hand, the patients with PWI had greater atrial tachycardia (AT) recurrence rate than those without PWI (10.0% vs. 2.5%, p = 0.003). CONCLUSIONS: PWI, in addition to PVI and LVZ modification, may improve single procedural outcomes in patients with PerAF who have LVZ, regardless of the distribution in the LA. A combination of voltage-guided ablation and PWI may be a simple, tailored, and effective ablation strategy.

Hemodynamic Collapse Caused by Cardiac Dysfunction and Abdominal Compartment Syndrome in a Patient with Mitochondrial Disease.

We herein report a case of mitochondrial disease with heart and intestinal tract involvement resulting in hemodynamic collapse. A 66-year-old woman was transferred to our hospital because of cardiogenic shock. Vasopressors were administered, and a circulatory support device was deployed. However, her hemodynamics did not improve sufficiently, and we detected abdominal compartment syndrome caused by the aggravation of chronic intestinal pseudo-obstruction as a complication. Insertion of a colorectal tube immediately decreased the intra-abdominal pressure, improving the hemodynamics. Finally, we diagnosed her with mitochondrial disease, concluding that the resulting combination of acute heart failure and abdominal compartment syndrome had aggravated the hemodynamics.

Hybrid Rubisco with Complete Replacement of Rice Rubisco Small Subunits by Sorghum Counterparts Confers C4 Plant-like High Catalytic Activity.

Photosynthetic rate at the present atmospheric condition is limited by the CO2-fixing enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) because of its extremely low catalytic rate (kcat) and poor affinity for CO2 (Kc) and specificity for CO2 (Sc/o). Rubisco in C4 plants generally shows higher kcat than that in C3 plants. Rubisco consists of eight large subunits and eight small subunits (RbcS). Previously, the chimeric incorporation of sorghum C4-type RbcS significantly increased the kcat of Rubisco in a C3 plant, rice. In this study, we knocked out rice RbcS multigene family using the CRISPR-Cas9 technology and completely replaced rice RbcS with sorghum RbcS in rice Rubisco. Obtained hybrid Rubisco showed almost C4 plant-like catalytic properties, i.e., higher kcat, higher Kc, and lower Sc/o. Transgenic lines expressing the hybrid Rubisco accumulated reduced levels of Rubisco, whereas they showed slightly but significantly higher photosynthetic capacity and similar biomass production under high CO2 condition compared with wild-type rice. High-resolution crystal structural analysis of the wild-type Rubisco and hybrid Rubisco revealed the structural differences around the central pore of Rubisco and the ßC-ßD hairpin in RbcS. We propose that such differences, particularly in the ßC-ßD hairpin, may impact the flexibility of Rubisco catalytic site and change its catalytic properties.

Differences in pharmacological property between combined therapy of the vasopressin V2-receptor antagonist tolvaptan plus furosemide and monotherapy of furosemide in patients with hospitalized heart failure.

BACKGROUND: Tolvaptan has been shown to improve congestion in heart failure patients. The purpose of this study was to evaluate the pharmacology and clinical efficacy of combined tolvaptan and furosemide therapy. METHODS: This study included 40 patients with systemic volume overload who were hospitalized for heart failure. Patients who showed no improvement in the condition after receiving 20 mg intravenous furosemide were included and were randomly selected to receive tolvaptan as an add-on to furosemide or to receive an increased dose of furosemide. We evaluated the bioelectrical impedance analyzer parameters, the parameters of the inferior vena cava using echocardiography, vital signs, body weight, urine output, and laboratory data for 5 days. RESULTS: In the changes from baseline between intracellular water volume (ICW) and extracellular water volume (ECW) after additional use of tolvaptan or furosemide from Day 1 to Day 5, there were no significant differences observed between ICW and ECW over 5 days in the tolvaptan + furosemide group, although differences were found in the furosemide group from Day 2 onward. Changes in the respiratory collapse of inferior vena cava increased significantly, and systolic blood pressure decreased significantly only in the furosemide group. CONCLUSIONS: The present study clearly demonstrates that combined therapy with tolvaptan and furosemide removed excess ICW and ECW to an equal extent, while furosemide alone primarily removed ECW, including intravascular water.

Clinical significance of arterial stiffness as a factor for hospitalization of heart failure with preserved left ventricular ejection fraction: a retrospective matched case-control study.

BACKGROUND: Previous studies have been conducted to identify characteristics of patients with heart failure with preserved ejection fraction (HFpEF), but the risk factors of HFpEF remain unclear. We investigated the associations between arterial stiffness and the risk of hospitalization for HFpEF patients. METHODS: For the case group, we enrolled patients with preserved EF who had been hospitalized for HF from April 2013 to March 2015 and examined the cardio-ankle vascular index (CAVI). For the control group, we enrolled outpatients with preserved EF and with hypertension, diabetes mellitus, dyslipidemia, and/or coronary artery disease but who did not present with HF symptoms and had never been diagnosed or treated for HF during the same period. The control group matched with the case group for age and sex. The association between hospitalized HFpEF and clinical variables was analyzed using conditional logistic regression models. RESULTS: The CAVI value was significantly higher in patients with hospitalized HFpEF compared with patients with the control [10.4 (9.8-11.0) vs. 9.2 (8.1-10.0), p < 0.001). On the multivariate conditional logistic regression analysis, high CAVI (OR 6.76, 95% CI 2.28-20.10, p < 0.001) and anemia (OR 3.91, 95% CI 1.47-10.40, p = 0.006) were independently associated with hospitalization of HFpEF patients. CONCLUSIONS: The present study has demonstrated that the high value of CAVI was independently associated with the hospitalization of HFpEF patients.

Adsorption kinetics and mechanisms of copper ions on activated carbons derived from pinewood sawdust by fast H3PO4 activation.

Two kinds of pinewood sawdust activated carbon adsorbents were prepared by fast activation with H3PO4 in a spouted bed, and the application in adsorption of copper ions was investigated. With only 3 min of activation time, the BET surface area of activated carbons reached 1537.5 m2/g for impregnation mass ratio of H3PO4 to sawdust at 1:1 and activation temperature of 500 °C (IR1-500), whereas it was 1750.7 m2/g for the impregnation ratio at 4:1 and activation temperature of 800 °C (IR4-800). The pseudo second-order reaction kinetics well describes the experimental adsorption of copper ion in this study, indicating chemisorption dominated in the process. By the C1s spectrum, activated carbons from IR1-500 contained more carboxyl groups (-COOH) and carbonyl groups (C=O), which played an important role in copper ions adsorption. In addition, it was found that the P-containing groups (metaphosphates) also involved in the adsorption of copper ion.

Raw walnut shell modified by non-thermal plasma in ultrafine water mist for adsorptive removal of Cu(ii) from aqueous solution.

Non-thermal plasma in ultrafine water mist (UWM) is proposed to increase the content of COOH groups on the surface of raw walnut shell in order to improve its performance in the removal of Cu(ii) from wastewater. The modified walnut shell surface was characterized by various techniques (BET, SEM-EDX and XPS), and it was observed that more COOH groups were generated. Oxygen disassociated from water mist by plasma bonded with the walnut shell to form activated sites of COOH groups. After Cu(ii) adsorption, the COOH group content in the walnut shell decreased because some groups were changed into C-O groups by Cu(ii) chemisorption with COOH groups. The Cu(ii) removal efficiency was 33.5% for raw walnut shell; however, the efficiency increased to 98% after plasma modification for 15 min under 3 g min-1 water mist. The maximum Cu(ii) adsorption capacity of the UWM-plasma-modified WNS was 39.4 mg g-1 at pH 5.3 and 25 °C, around 8 times that of the raw WNS. This implies that UWM-plasma modification is a potential method for improving the Cu(ii) adsorption performance of raw biomass.

The effect of 3D carbon nanoadditives on lithium hydroxide monohydrate based composite materials for highly efficient low temperature thermochemical heat storage.

Lithium hydroxide monohydrate based thermochemical heat storage materials were modified with in situ formed 3D-nickel-carbon nanotubes (Ni-CNTs). The nanoscale (5-15 nm) LiOH·H2O particles were well dispersed in the composite formed with Ni-CNTs. These composite materials exhibited improved heat storage capacity, thermal conductivity, and hydration rate owing to hydrogen bonding between H2O and hydrophilic groups on the surface of Ni-CNTs, as concluded from combined results of in situ DRIFT spectroscopy and heat storage performance test. The introduction of 3D-carbon nanomaterials leads to a considerable decrease in the activation energy for the thermochemical reaction process. This phenomenon is probably due to Ni-CNTs providing an efficient hydrophilic reaction interface and exhibiting a surface effect on the hydration reaction. Among the thermochemical materials, Ni-CNTs-LiOH·H2O-1 showed the lowest activation energy (23.3 kJ mol-1), the highest thermal conductivity (3.78 W m-1 K-1) and the highest heat storage density (3935 kJ kg-1), which is 5.9 times higher than that of pure lithium hydroxide after the same hydration time. The heat storage density and the thermal conductivity of Ni-CNTs-LiOH·H2O are much higher than 1D MWCNTs and 2D graphene oxide modified LiOH·H2O. The selection of 3D carbon nanoadditives that formed part of the chemical heat storage materials is a very efficient way to enhance comprehensive performance of heat storage activity components.

The Iron Chaperone Protein CyaY from Vibrio cholerae Is a Heme-Binding Protein.

CyaY is an iron transport protein for iron-sulfur (Fe-S) cluster biosynthetic systems. It also transports iron to ferrochelatase that catalyzes insertion of Fe2+ into protoporphyrin IX. Here, we find that CyaY has the ability to bind heme as well as iron, exhibiting an apparent dissociation constant for heme of 21 ± 6 nM. Absorption and resonance Raman spectra revealed that both ferric and ferrous forms of heme were bound to an anionic ligand (e.g., tyrosine and/or cysteine). Consistent with this, mutagenesis studies showed that Tyr67 and Cys78 are possible heme ligands of CyaY. The binding of heme to CyaY increased the apparent dissociation constant of CyaY for iron from 65.2 to 87.9 µM. Circular dichroism spectra of CyaY suggested that binding of heme to CyaY induces rearrangement of aromatic residues. Furthermore, size-exclusion column chromatography demonstrated heme-mediated oligomerization of CyaY. These results suggest that heme binding induces conformational changes, including oligomerization of CyaY, that result in a decrease in the affinity of CyaY for iron. Accordingly, the presence of excess heme in cells would lead to modulation of Fe-S cluster or heme biosynthesis. This report provides the first description of heme dependence of iron transport by CyaY.

Nonactivated and activated biochar derived from bananas as alternative cathode catalyst in microbial fuel cells.

Nonactivated and activated biochars have been successfully prepared by bananas at different thermotreatment temperatures. The activated biochar generated at 900°C (Biochar-act900) exhibited improved oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) performances in alkaline media, in terms of the onset potential and generated current density. Rotating disk electron result shows that the average of 2.65 electrons per oxygen molecule was transferred during ORR of Biochar-act900. The highest power density of 528.2 mW/m(2) and the maximum stable voltage of 0.47 V were obtained by employing Biochar-act900 as cathode catalyst, which is comparable to the Pt/C cathode. Owning to these advantages, it is expected that the banana-derived biochar cathode can find application in microbial fuel cell systems.

Electrodeposition of anchored polypyrrole film on microelectrodes and stimulation of cultured cardiac myocytes.

The electrically conducting polymer polypyrrole (PPy) was electrochemically deposited onto Pt microelectrodes on a polyimide (PI) substrate. Pre-modification of the PI surface with a self-assembled monolayer of octadecyltrichlorosilane-induced anisotropic lateral growth of PPy along the PI surface and enhanced adhesive strength of the PPy film. The lateral growth of PPy film around the electrode anchored the whole film to the substrate. External stimulation of cultured cardiac myocytes was carried out using the PPy-coated microelectrode. The myocytes on the microelectrode substrate were electrically conjugated to form a sheet, and showed synchronized beating upon stimulation. The threshold charge for effective stimulation of a 0.8 cm(2) sheet of myocytes was around 0.2 microC, roughly corresponding to a membrane depolarization of 250 mV.

Oral clonidine premedication exacerbates hypotension following tourniquet deflation by inhibiting noradrenaline release.

Clonidine premedication prevents tourniquet pain and reduces sympathetic nerve activity. We evaluated hemodynamic changes and catecholamine release following tourniquet deflation during spinal anesthesia in patients who received oral clonidine premedication. The final analysis included 24 otherwise healthy patients undergoing lower-limb surgery randomly assigned to two groups: those receiving approximately 5 micrograms/kg of oral clonidine 1 hr before anesthesia (clonidine group, n = 12), and those receiving no premedication (control group, n = 12). After lumbar anesthesia, a tourniquet was applied for approximately 60 minutes to each patient. Electrocardiogram, arterial blood pressure, and consumption of butorphanol for tourniquet pain were monitored. Blood samples were obtained at different times to measure serum concentration of catecholamine. In the clonidine group, mean blood pressure decreased from 87 +/- 7 mmHg at baseline to 65 +/- 10 mmHg after tourniquet deflation (P < 0.05). This peak reduction of mean blood pressure in the clonidine group was significantly lower than in the control group. After receiving clonidine premedication, the plasma noradrenaline concentrations in the clonidine group were significantly lower than those in the control group. Noradrenaline concentration increased in the control group from 162.3 +/- 89.2 pg/mL before tourniquet deflation to 199.3 +/- 95.7 pg/mL afterward (P < 0.01), but there was no significant change in noradrenaline concentration after tourniquet deflation in the clonidine group. We conclude that oral clonidine premedication exacerbated the reduction in mean blood pressure following tourniquet deflation by inhibiting noradrenaline release.