Enhancing Long-Term Durability of Electrochemical Reactors Producing Formate from CO2 and Water Designed for Integration with Solar Cells.

Artificial photosynthetic cells producing organic matter from CO2 and water have been extensively studied for carbon neutrality, and the research trend is currently transitioning from proof of concept using small-sized cells to large-scale demonstrations for practical applications. We previously demonstrated a 1 m2 size cell in which an electrochemical (EC) reactor featuring a ruthenium (Ru)-complex polymer (RuCP) cathode catalyst was integrated with photovoltaic cells. In this study, we tackled the remaining issue to improve the long-term durability of cathode electrodes used in the EC reactors, demonstrating high Faradaic efficiencies exceeding 80% and around 60% electricity-to-chemical energy-conversion efficiencies of a 75 cm2 sized EC reactor after continuous operation for 3000 h under practical conditions. Introduction of a pyrrole derivative containing an amino group in the RuCP coupled with UV-ozone treatment to create carboxyl groups on the carbon supports effectively reduced the detachment of the RuCP catalyst by forming a strong amide linkage. A newly developed chemically resistant graphite adhesive prevented the carbon supports from peeling off of the conductive substrates. In addition, highly durable anodes composed of IrOx-TaOy/Pt-metal oxide/Ti were adopted. Even though the EC reactor was installed at an inclined angle of 30°, which is approximately the optimal angle for receiving more solar energy, the crossover reactions were sufficiently suppressed because the porous separator film impeded the transfer of oxygen gas bubbles from the anode to the cathode. The intermittent operation improved the energy-conversion efficiency because the accumulated bubbles were removed at night.

Regulatory effects of cervical sympathetic trunk and renal sympathetic nerve activities on cerebral blood flow during head-down postural rotations.

This study attempts to clarify the neural control of cerebral blood flow (CBF) during head-down postural rotation, which induces a cephalad fluid shift in urethane-anesthetized rats. The animals were placed on a table, tilted to a 45° head-down position over 5 s and maintained in that position. Head-down rotation (HDR) induced a transient decrease (8 ± 3 mm Hg; mean ± SE) in mean arterial blood pressure (ABP) at 7.3 ± 0.3 s after the onset of HDR. The pressure returned to the pre-HDR level within 1 min in the head-down position. Pretreatment with hexamethonium bromide suppressed the HDR-elicited decrease in ABP, suggesting that the decrease in ABP was induced by the suppression of autonomic neural outflow. The administration of phenoxybenzamine (PB), an α-adrenergic antagonist, also eliminated the HDR-elicited decrease in ABP, suggesting that this decrease was elicited by the suppression of α-adrenergic vascular tone. To test sympathetic outflow during HDR, renal sympathetic nerve activity (RSNA) and cervical sympathetic trunk (CST) activity (CSTA) were recorded. RSNA was transiently suppressed at 2.3 ± 0.4 s after HDR onset, followed by a decrease in ABP, suggesting that this decrease was, at least in part, induced by the suppression of sympathetic nerves. CSTA did not change significantly during HDR. These results suggest that HDR suppresses sympathetic nerves in the lower body rather than in the head, which might result in a decrease in ABP. To test the effect of the decrease in ABP due to sympathetic activity on CBF during HDR, changes in CBF during HDR were measured. CBF did not change significantly during HDR in the control group after the administration of an α-receptor blocker or after denervation of the CSTs. These results suggest that the impact of the CSTs on CBF is likely to be limited by a rapid increase in CBF due to HDR-elicited cephalad fluid shift and that CBF autoregulation proceeds through an alternative mechanism involving the myogenic properties of cerebral vessels.

Fluctuations in dissolved oxygen concentration during a CHO cell culture process affects monoclonal antibody productivity and the sulfhydryl-drug conjugation process.

During a CHO cell culture production process, important parameters are generally well controlled by a feedback mechanism (PID loop) in order to ensure consistency in both productivity and product quality. These parameters typically include pH, dissolved oxygen (DO), and temperature. While most of these parameters are very well controlled within their specific deadband, stable DO control can be challenging. Oscillations in DO concentration are not uncommon and these fluctuations can be exacerbated with an efficient mass transfer aeration strategy. In this study, where an IgG2 producing cell line was used, we observed increased lactate accumulation accompanied by decreased titer production in lots with fluctuations in DO concentration (DOF ) when compared with lots with stable DO control (DOS ). We demonstrate that DOF had a greater impact on performance with respect to titer production and lactate accumulation than DO setpoint. Furthermore, we report that estimated specific oxygen uptake rates (qOURs) were lower in DOF lots when compared with DOS lots. We also report that purified mAb sourced from DOF lots yielded lower drug-to-antibody ratio (DAR) after the sulfhydryl-targeted maleimide conjugation process when equivalent reducing agent was used. All mAb lots were within the analytical specifications for release, though a slight increase in measureable trisulfides were observed in DOF mAb lots. DO control aimed to minimize fluctuations around DO setpoint was essential for us to produce consistent DAR without adjusting the conjugation process. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:1427-1437, 2018.

Adaptation to microgravity, deconditioning, and countermeasures.

Humans are generally in standing or sitting positions on Earth during the day. The musculoskeletal system supports these positions and also allows motion. Gravity acting in the longitudinal direction of the body generates a hydrostatic pressure difference and induces footward fluid shift. The vestibular system senses the gravity of the body and reflexively controls the organs. During spaceflight or exposure to microgravity, the load on the musculoskeletal system and hydrostatic pressure difference is diminished. Thus, the skeletal muscle, particularly in the lower limbs, is atrophied, and bone minerals are lost via urinary excretion. In addition, the heart is atrophied, and the plasma volume is decreased, which may induce orthostatic intolerance. Vestibular-related control also declines; in particular, the otolith organs are more susceptible to exposure to microgravity than the semicircular canals. Using an advanced resistive exercise device with administration of bisphosphonate is an effective countermeasure against bone deconditioning. However, atrophy of skeletal muscle and the heart has not been completely prevented. Further ingenuity is needed in designing countermeasures for muscular, cardiovascular, and vestibular dysfunctions.

Vaccine efficacy of transcutaneous immunization with amyloid ß using a dissolving microneedle array in a mouse model of Alzheimer's disease.

Vaccine therapy for Alzheimer's disease (AD) based on the amyloid cascade hypothesis has recently attracted attention for treating AD. Injectable immunization using amyloid ß peptide (Aß) comprising 1-42 amino-acid residues (Aß1-42) as antigens showed therapeutic efficacy in mice; however, the clinical trial of this injected Aß1-42 vaccine was stopped due to the incidence of meningoencephalitis caused by excess activation of Th1 cells infiltrating the brain as a serious adverse reaction. Because recent studies have suggested that transcutaneous immunization (TCI) is likely to elicit Th2-dominant immune responses, TCI is expected to be effective in treating AD without inducing adverse reactions. Previously reported TCI procedures employed complicated and impractical vaccination procedures; therefore, a simple, easy-to-use, and novel TCI approach needs to be established. In this study, we investigated the vaccine efficacy of an Aß1-42-containing TCI using our novel dissolving microneedle array (MicroHyala; MH) against AD. MH-based TCI induced anti-Aß1-42 immune responses by simple and low-invasive application of Aß1-42-containing MH to the skin. Unfortunately, this TCI system resulted in little significant improvement in cognitive function and Th2-dominant immune responses, suggesting the need for further modification.

Effect of isolated AMP deaminase deficiency on skeletal muscle function.

Mutation of the AMP deaminase 1 (AMPD1) gene, the predominate AMPD gene expressed in skeletal muscle, is one of the most common inherited defects in the Caucasian population; 2-3% of individuals in this ethnic group are homozygous for defects in the AMPD1 gene. Several studies of human subjects have reported variable results with some studies suggesting this gene defect may cause symptoms of a metabolic myopathy and/or easy fatigability while others indicate individuals with this inherited defect are completely asymptomatic. Because of confounding problems in assessing muscle symptoms and performance in human subjects with different genetic backgrounds and different environmental experiences such as prior exercise conditioning and diet, a strain of inbred mice with selective disruption of the AMPD1 was developed to study the consequences of muscle AMPD deficiency in isolation. Studies reported here demonstrate that these animals are a good metabolic phenocopy of human AMPD1 deficiency but they exhibit no abnormalities in muscle performance in three different exercise protocols.

Analysis of transcutaneous antigenic protein delivery by a hydrogel patch formulation.

We have developed a hydrogel patch, which could promote antigen penetration through stratum corneum (SC), and have demonstrated its safety and efficacy in animals and humans. For the availability improvement of our system, it is important to develop a device, which enhances antigen penetration through SC more efficiently. In this study, we have tried to collect the basic information involved in transcutaneous antigen delivery by investigating the immune event induced by our system and examining the effect of physical property of antigens or patch component on antigen penetration. A hydrogel patch delivered antigens through SC into skin, and some of Langerhans cells captured antigens, activated, and migrated to regional lymph nodes. We also showed that protein distribution into SC was regulated by various complexly-intertwined factors of proteins but not one particular parameter. Additionally, glycerin as the patch component contributed to the formation of SC hydration by patch application, which might be one of the factors of acceleration of protein penetration. On the basis of the present information, we are planning to modify the patch composition and establish the antigen modification technology for improvement in the efficacy of transcutaneous immunization.

Three-Dimensional Periodically Ordered Nanohetero Metallic Materials from Self-Assembled Block Copolymer Composites.

We report a synthetic route to inorganic nanoheterostructures with tunable size and morphology via self-assembled block copolymer mesophase templates. Two Fe precursors, tricarbonyl(cyclooctatetraene) iron and acetylacetonate iron(III), and one Pt precursor, platinum dimethylcyclooctadiene, were selectively introduced into separate polymer blocks of a block copolymer, polystyrene-b-poly-4-vinylpyridine, and then the block copolymer templates were removed by pyrolysis. Self-assembled inorganic nanoheterostructures (spheres, hexagonal cylinders, and layers of hard magnetic phase FePt in a matrix of soft magnetic phase α-Fe) were produced. The morphology and domain size of the nanoheterostructures could be tailored by controlling the molecular weight and relative block lengths of the block copolymers. The controlled size and morphology of the inorganic nanoheterostructures demonstrate the method's utility for producing highly functional materials.

Tumor vascular targeted delivery of polymer-conjugated adenovirus vector for cancer gene therapy.

Previously, we generated a cancer-specific gene therapy system using adenovirus vectors (Adv) conjugated to polyethylene glycol (Adv-PEG). Here, we developed a novel Adv that targets both tumor tissues and tumor vasculatures after systemic administration by conjugating CGKRK tumor vasculature homing peptide to the end of a 20-kDa PEG chain (Adv-PEG(CGKRK)). In a primary tumor model, systemic administration of Adv-PEG(CGKRK) resulted in ~500- and 100-fold higher transgene expression in tumor than that of unmodified Adv and Adv-PEG, respectively. In contrast, the transgene expression of Adv-PEG(CGKRK) in liver was about 400-fold lower than that of unmodified Adv, and was almost the same as that of Adv-PEG. We also demonstrated that transgene expression with Adv-PEG(CGKRK) was enhanced in tumor vessels. Systemic administration of Adv-PEG(CGKRK) expressing the herpes simplex virus thymidine kinase (HSVtk) gene (Adv-PEG(CGKRK)-HSVtk) showed superior antitumor effects against primary tumors and metastases with negligible side effects by both direct cytotoxic effects and inhibition of tumor angiogenesis. These results indicate that Adv-PEG(CGKRK) has potential as a prototype Adv with suitable efficacy and safety for systemic cancer gene therapy against both primary tumors and metastases.

Vestibular control of arterial blood pressure during head-down postural change in anesthetized rabbits.

This study was undertaken to elucidate neural control of the arterial blood pressure (ABP) in head-down postural change which causes both stimulation to the vestibular system and head-ward fluid shift. Experiments were carried out with urethane-anesthetized rabbits. The animal was mounted on a tilting table, tilted to 45 degrees head-down in 5 s, and kept at the position for 5 min. The head-down rotation (HDR) induced a transient decrease in ABP (10 +/- 3 mmHg; mean +/- SE), and then the pressure gradually recovered toward the pre-HDR level during the 5 min at the head-down position. Pretreatment with hexamethonium bromide, a ganglionic transmission blocker, suppressed the HDR-induced drop of ABP, suggesting that the ABP drop was induced by an inhibition of autonomic neural outflows. Renal sympathetic nerve activity (RSNA) decreased considerably after 1.6 +/- 0.2 s from the onset of HDR, which was followed by the ABP drop. Aortic depressor nerve activity (ADNA), an afferent for baroreceptor reflex, increased significantly during the rotation, but the peak of ADNA increase was 3.2 +/- 0.5 s after the initiation of the HDR. Therefore, the suppression of RSNA seems to be induced mainly by a quicker mechanism than baroreceptor reflex. In order to test the possibility, we examined changes in ABP and RSNA during HDR using vestibular-lesioned rabbits. In these rabbits, RSNA and ABP did not change significantly during HDR. These results suggest that vestibular organs play a role in the transient drop in ABP induced by HDR through the suppression of sympathetic nerve outflows.

Hydrogen absorption and desorption by the Li-Al-N-H system.

Lithium hexahydridoaluminate Li(3)AlH(6) and lithium amide LiNH(2) with 1:2 molar ratio were mechanically milled, yielding a Li-Al-N-H system. LiNH(2) destabilized Li(3)AlH(6) during the dehydrogenation process of Li(3)AlH(6), because the dehydrogenation starting temperature of the Li-Al-N-H system was lower than that of Li(3)AlH(6). Temperature-programmed desorption scans of the Li-Al-N-H system indicated that a large amount of hydrogen (6.9 wt %) can be released between 370 and 773 K. After initial H(2) desorption, the H(2) absorption and the desorption capacities of the Li-Al-N-H system with a nano-Ni catalyst exhibited 3-4 wt % at 10-0.004 MPa and 473-573 K, while the capacities of the system without the catalyst were 1-2 wt %. The remarkably increased capacity was due to the fact that the kinetics was improved by addition of the nano-Ni catalyst.

Hydrogen storage of metal nitride by a mechanochemical reaction.

Metal imides (Li(2)NH, CaNH), a metal amide (LiNH(2)) and metal hydrides (LiH, CaH(2)) were synthesized by ball milling of their respective metal nitrides (Li(3)N, Ca(3)N(2)) in a H(2) atmosphere at 1 MPa and at room temperature.

Effects of head-down tilt on the intracranial pressure in conscious rabbits.

Head-down tilt (HDT) causes a fluid shift towards the upper body, which increases intracranial pressure (ICP). In the present study, the time course of ICP changes during prolonged exposure to HDT was investigated in conscious rabbits through a catheter chronically implanted into the subarachnoid space. The production of cerebrospinal fluid (CSF) after exposure to 7-days HDT was also examined by a ventriculo-cisternal perfusion method. The ICP increased from 4.3+/-0.4 (mean+/-S.E.M.) mmHg to 8.0+/-0.8 mmHg immediately after the onset of 45 degrees HDT, reached a peak value of 15.8+/-1.9 mmHg at 11 h, and then decreased to 10.4+/-1.1 mmHg at 24 h. During 7-days HDT, it also increased from 4.8+/-0.9 mmHg to 9.2+/-1.6 mmHg immediately after the onset of 45 degrees HDT, reached a peak value of 12.8+/-2.5 mmHg at 12 h of HDT, and then decreased gradually towards the pre-HDT baseline value for 7 days. The rate of CSF production was 10.1+/-0.6 microl/min in rabbits exposed to 7-days HDT, and 9.7+/-0.5 microl/min in control rabbits. These results suggest that the rabbits begin to adapt to HDT within a few days and that the production of CSF is preserved after exposure to 7-days HDT. The time course of ICP changes during HDT in conscious rabbits seems to be considerably different from that in anesthetized rabbits.

Selective occlusion of lumbar arteries as a spinal cord ischemia model in rabbits.

Paraplegia is a devastating complication of operations requiring transient occlusion of the descending thoracic aorta. Many animal models of spinal cord ischemia have been utilized to examine the efficacy of various neuroprotective methods. In this study, we establish a rabbit model of spinal cord ischemia by selective temporary occlusion of lumbar arteries and examine the protective effects of systemic mild hypothermia in this model. Animals were divided into the following four groups: sham group (group A, n = 6); 10 min ischemia, normothermia (39 degrees C) (group B, n = 6); 20 min ischemia, normothermia (group C, n = 6); and 30 min ischemia, mild hypothermia (35 degrees C) (group D, n = 6). After 7 d of reperfusion, three rabbits in group B and five rabbits in group C developed paraplegia (Tarlov's score = 0). In contrast, all rabbits preserved hindlimb motor function (Tarlov's score = 4) in groups A and D. Histological findings indicated that the number of motor neurons in the anterior horns in group C were significantly fewer than in group A. A large number of motor neurons were preserved in group D. Hypothermia is known to be an effective and reliable method of neuroprotection, but the risk of complications rises at deep hypothermia. Our current results confirm that systemic, mild hypothermia is a safe and effective neuroprotective method during ischemia-reperfusion injury of the spinal cord.

Age-dependent changes of postischemic reperfusion in rat skin.

Ischemia-reperfusion plays a certain role in causing skin damage associated with pressure sores. In this study, changes in cutaneous hemodynamics during reperfusion were investigated in young and older rats. After cessation of 1-hour or 2-hour ischemia, the skin blood flow increased transiently (postischemic hyperemia) and quickly returned to the baseline in young and older rats. After 4-hour ischemia, however, the postischemic hyperemia was reduced in both groups, and the skin blood flow decreased below the baseline for a few hours in older rats. The skin blood flow tolerated well the repeated exposures to 1-hour ischemia in both groups. In 2-hour ischemia experiments, the postischemic hyperemia was preserved after the second ischemic period in young rats but not in older rats. These results suggest that the tolerance of skin microcirculation to ischemia-reperfusion may decrease with increasing age.

Effects of head-down tilt on cerebral blood flow and somatosensory-evoked potentials in rabbits.

Changes in cerebral blood flow (CBF) and somatosensory-evoked potentials (SEPs) were studied in rabbits exposed to head-down tilt (HDT) at 45 degrees and 75 degrees. The animals were anesthetized with alpha chloralose and the lungs were artificially ventilated. CBF was continuously measured by laser Doppler flowmetry (LDF), and SEPs were recorded as responses of the cortex to median nerve stimulation. In the 45 degrees HDT rabbits, CBF did not change significantly in the parietal cortex during 1 h of HDT. In contrast, in the 75 degrees HDT rabbits, CBF did not change significantly within 5 min after the onset of HDT, but decreased gradually to 79% of the pre-HDT baseline value at the end of 1 h of HDT. The latency and amplitude of SEPs did not change significantly throughout the experiment in any group. These results suggest that CBF and SEPs do not change significantly during 1 h of 45 degrees HDT and that 75 degrees HDT disturbs the regulation of the cerebral circulation but does not affect cortical somatosensory response, at least for 1 h.

Effects of head-down tilt on cerebral blood flow in humans and rabbits.

Changes in cerebral hemodynamics, during and after head down tilt (HDT), were examined by means of transcranial Doppler technique (TCD) and near infrared spectroscopy (NIRS) in humans, and laser Doppler flowmetry (LDF) in rabbits. Mean cerebral blood flow (CBF) velocity measured by TCD increased during the first 6 h of HDT compared with the pre-HDT value. NIRS experiments demonstrated that brain oxygenation and hemoglobin concentration increased with postural change from upright to supine. These results suggest that exposure to HDT increases CBF during the early phase of HDT in humans. In rabbits anesthetized with alpha chloralose, on the other hand, 45 degrees HDT did not change CBF significantly in the parietal cortex during 1 h after the onset of HDT. The discrepancy may be explained by the difference in species, tilt angle, or the brain region where CBF has been measured.

Changes of intracranial pressure during head-down tilt in anesthetized and conscious rabbits.

Effects of head-down tilt on intracranial pressure were studied in anesthetized and conscious rabbits. Adult Japanese white rabbits of both sexes, weighing 2.5-3.5 kg, were used in the experiments. Experiment 1. Animals were anesthetized with pentobarbital, and ICP was monitored through a catheter inserted into the subarachnoid space. ICP elevated immediately after the onset of 45 degrees HDT and gradually reduced toward the baseline level in the next 8 hours. Experiment 2. Each rabbit was exposed to 45 degrees HDT for 24 hours and the ICP was measured through a catheter which had been implanted 7 days before. In the conscious rabbits, ICP increased about 4 mmHg after the onset of 45 degrees HDT, further increased gradually to the peak at 11 hours of HDT, and then started to return to the baseline. These results suggest that the time course of the change in ICP during HDT is considerably different between anesthetized and conscious rabbits.