Bath Conditions Research Articles

The effect of Jujuboside A on the evoked field potentials of granule cells in dentate gyrus

Jujuboside A (JuA) is a main component of Jujubogenin extracted from the seeds of Ziziphus. The authors have not seen any report on JuA's direct effect on the neurons of the central nervous system. This study aimed to assess the effect of JuA on paired-pulse responses of dentate gyrus granule cells in urethane-anaestherized rats, used intracerebroventricular (i. c. v.) JuA to mimic in vitro bath conditions in vivo. Paired-pulse stimuli with 80ms interpulse interval were used to stimulate the perforant pathway. Evoked responses were recorded in the dentate gyrus cell layer after i. c. v. administration of 0.9% normal saline or JuA. In the first responses, the slopes of excitatory postsynaptic potential (EPSP1) and the amplitudes of population spike (PS1) decreased significantly after administration of JuA while the PS1 latencies increased significantly. In the second responses, the EPSP2 slopes and PS2 latencies were changed similarly to those of the first ones, but PS2 amplitudes increased. The results showed that JuA may have some inhibitory effect on the granule cell excitability mediated by presynaptic mechanism but may have little effect on the excitability mediated by postsynaptic mechanism since the second evoked N-methyl-D-aspartic mediating paired-pulse facilitation is a postsynaptic mechanism.

Electroless nickel films: properties and fabricated cavity structure

Properties of 6-/spl mu/m-thick films of electroless, phosphorus-containing nickel grown on evaporated Ni seed layers were measured as a function of bath conditions. The bath variables were temperature, pH, and hypophosphorus acid concentration. Residual mechanical stress at room temperature was measured by a bulge test method, as was elastic modulus. Growth rate, crystallinity, and phosphorus content were also measured. Stress was sensitive to all bath variables, and the range encountered was 4 MPa compressive to 255 MPa tensile. A proper set of nickel growth conditions combined with the use of a stiction-inhibiting parylene-D film led to the successful fabrication of a self-supported roof structure forming a large-area, sealable cavity.

Effects of passive body heating on body temperature and sleep regulation in the elderly: a systematic review

Insomnia in the elderly is associated with circadian body temperature changes. Manipulating body temperature prior to sleep onset may improve sleep quality in the elderly. This systematic review analyzed the effect of passive body heating on body temperature and sleep quality. Three studies related to passive body heating for the elderly identified from a computerized database search were evaluated. All of them used crossover designs to examine effects of passive body heating on sleep quality. Passive body heating such as a warm bath immersed to mid-thorax with 40–41°C water for 30 min in the evening could increase rectal body temperature, delay occurrence of body temperature nadir and increase slow wave sleep (deep sleep) in healthy female elderly with insomnia. The elderly also perceived “good sleep” or “quickness of falling asleep” after the bathing condition. Evening warm bath facilitates nighttime sleep for the healthy elderly with insomnia.

Understanding and troubleshooting decorative nickel electroplating systems—part I: Introduction and brightness problems

Desktop flatbed scanners are very well-known devices that can provide digitized information of flat surfaces. They are practically present in most laboratories as a part of the computer support. Several quality levels can be found in the market, but all of them can be considered as tools with a high performance and low cost. The present paper shows how the information obtained with a scanner, from a flat surface, can be used with fine results for exploratory and quantitative purposes through image analysis. It provides cheap analytical measurements for assessment of quality parameters of coated metallic surfaces and monitoring of electrochemical coating bath lives. The samples used were steel sheets nickel-plated in an electrodeposition bath. The quality of the final deposit depends on the bath conditions and, especially, on the concentration of the additives in the bath. Some additives become degraded with the bath life and so is the quality of the plate finish. Analysis of the scanner images can be used to follow the evolution of the metal deposit and the concentration of additives in the bath. Principal component analysis (PCA) is applied to find significant differences in the coating of sheets, to find directions of maximum variability and to identify odd samples. The results found are favorably compared with those obtained by means of specular reflectance (SR), which is here used as a reference technique. Also the concentration of additives SPB and SA-1 along a nickel bath life can be followed using image data handled with algorithms such as partial least squares (PLS) regression and support vector regression (SVR). The quantitative results obtained with these and other algorithms are compared. All this opens new qualitative and quantitative possibilities to flatbed scanners.

Surface Morphology and Crystallographic Orientation of Electrodeposited Iron Films

The crystallographic structure and surface morphology of Fe films electrodeposited from three kinds of baths, sulfate, chloride and sulfamate baths, were studied by SEM, XRD. The surface morphology and crystallographic orientation of Fe films deposited on a Ni-P amorphous substrate were varied with electrodeposition bath composition and conditions. The {211} plane appeared to be mainly a preferential orientation of films deposited from all baths examined in this study.

Diode-like single-ion track membrane prepared by electro-stopping

The preparation of an asymmetric membrane in poly(ethylene terephthalate) (PET) is described, using a combination of chemical and electro-stopping. For this purpose, a single-ion-irradiated PET film is inserted into an electrolytic cell and etched from one side in 9 M sodium hydroxide while bathing the other side in a mixture of 2 M KCl and 2 M HCOOH (1:1 by volume), electrically retracting the OH − ions from the tip of the etch pit during pore break-through. When a preset current has been reached, the etch process is interrupted by replacing the etching solution with acidic 1 M potassium chloride solution. After etching, the current–voltage ( I– V) characteristic is determined under symmetric bathing conditions, immersing both sides of the membrane in KCl solutions of identical concentration (0.01–1 M) and pH (3–8). The I– V characteristic is strongly non-linear, comparable to that of an electrical diode. If the polarity during etching is reversed, pushing the OH − ions into the tip of the etch pit, the resulting pores are larger and the degree of asymmetry smaller. The importance of electro-stopping is compared with chemical stopping.

Dual‐mode modeling of competitive and concentration‐dependent sorption and desorption kinetics of polycyclic aromatic hydrocarbons in soils

A radial dual‐mode diffusion model is proposed for mass transfer of hydrophobic compounds in soil organic matter (SOM) that is able to predict competitive and concentration effects on sorption and desorption rates. On the basis of dual‐mode sorption theory for glassy polymers the model assumes a population of specific adsorption sites (“holes”) interspersed uniformly in the dissolution (partition) domain of SOM. It further assumes Fickian diffusion in the dissolution domain and immobilization in the holes, with microscopic local equilibrium between the two domains. The model is solved numerically (Crank‐Nicolson implicit method). Using parameters from single‐solute equilibrium and kinetic experiments, the model adequately predicts batch transient sorption and desorption of phenanthrene (primary solute) as a function of pyrene (cosolute) concentration, and batch transient sorption of phenanthrene as a function of its own concentration, in two soils. The model shows that phenanthrene sorption approaches equilibrium faster with increasing cosolute or self‐concentration owing to the concentration dependence of the apparent diffusivity, as predicted by a simple hole‐plugging mechanism (i.e., fewer and fewer holes are available). Simulations show the effect to be greatest under infinite bath uptake conditions. Under finite bath conditions this positive effect on rate may be opposed by a batch process temporal bias present when the water:soil ratio is kept constant in a series of experiments. The bias is due to gradient driving force effects that slow the rate as a result of the decrease in percent of solute finally taken up by the solid as cosolute or concentration increases.

Influence of the synthesis parameters on the crystallization and magnetic properties of cobalt nanowires

Cobalt wires have been synthesized by electrodeposition in porous polycarbonate membranes with a pore diameter of ≈200 nm and a thickness of ≈6 μm . The influence of the citrate concentration, and different substrates (Ag, Cu), sputtered on the bottom of membranes, on the nanocrystalline structure and magnetic properties of the wires are discussed. Crystallization of the wires as a function of the synthesis bath conditions was measured by X-ray diffraction and the magnetic properties at room temperature were measured using vibrating-sample magnetometry. Differences, on deposition rate and crystalline domains size, have been observed, as well as the coercive forces and the hysteresis squareness change in the hysteresis loops of the wires depending on the citrate concentration in the electrochemical bath.

Zinc–nickel alloy coatings electrodeposited from a chloride bath using direct and pulse current

Zinc–nickel alloys were electrodeposited on steel from chloride bath by direct and pulse current. Some electric variables (average current density, pulse frequency, duty cycle) and some important bath conditions (ratio of Ni 2+/Zn 2+ in bath, temperature) on chemical compositions, current efficiency, microhardness and surface appearance of coatings were studied. At low current densities, transition from anomalous to normal co-deposition was observed for both direct and pulse current. Pulse current seems to increase brightness of the coating and to decrease the precipitation of zinc hydroxide at the cathode surface. In addition, applied pulse current increases the percentage of nickel in deposits. Pulse frequency and duty cycle had little effect on the chemical composition of deposits. The polarization curve of zinc–nickel deposition with pulse current is shifted to positive potentials in comparison with direct current curves. The temperature of the plating bath had a very strong effect on the composition of the deposits. This is primarily the result of intrinsically slow nickel kinetics. The hardness of Zn–Ni alloy coatings (approx. 220 VHN) was greater than the hardness of zinc coating (approx. 161 VHN). The hydroxide suppression mechanism for Zn–Ni co-deposition has been confirmed.

Morphology Evolution of Au/B4C Electrodeposited Composites / Morphologie-Entwicklung von galvanisch hergestellten Au/B4CVerbunden

Electrodeposition of Au/B 4 C composites is attractive for the achievement of hard and termally stable Au films displaying outstanding tribological performance. The addition of micrometric B 4 C particles to Au electrodeposition baths brings about time-dependent morphological variations on the micrometer scale, eventually reaching a steady state behaviour. These morphological variations are a function of growth rate, amount of particles suspended in the bath and hydrodynamic conditions. A systematic experimental investigation of these effects was carried out by in-plane and cross-sectional SEM observations. An image-analysis procedure for the evaluation of the effective surface area was set up. Correlations bewteen operating conditions and volume fraction of ceramic in the composite are proposed, based on image analysis of SEM micrographs. Morphology evolution data can be used to model independently measured electrochemical quantities related to the effective cathode surface area.

Relationship between the Crystallographic Structure of Electrodeposited Fe-Zn Alloy Film and Its Thermal Equilibrium Diagram

The crystallographic structure and morphology of electrodeposited Fe-Cr films under different bath conditions were studied in detail by using XRD, HRTEM and SEM. The crystallographic structures of the Fe-Cr electrodeposits were also compared with the Fe-Cr thermal equilibrium diagram. The results indicated that the crystallographic structure of electrodeposited Fe-Cr alloy film gradually changed from microcrystalline to amorphous with increasing Cr content. The deposited film exists as α-Fe solid solution when the Cr compositions of deposited films are below 3.1 at%, whereas, it existed as a meta-stable crystal when the Cr compositions of deposited films are from 4.5 at% to 22.4 at%, which have not been reported up to now. The deposited films with various Cr compositions from 22.9 at% to 74.4 at% chromium exist as amorphous phase. Hence, the crystallographic structure of the electrodeposited Fe-Cr alloy film is closely related to its thermal equilibrium diagram, but does not always agree with it.

Simulation of Shape Evolution during Electrodeposition of Copper in the Presence of Additive

Shape evolution during electrodeposition of copper in microtrenches was studied numerically by a model which incorporates adaptive meshing capabilities. Filling of trenches with copper without creating a void was related to plating additives in solution. The shape-change behavior of this system resulting from variation of the feature’s aspect ratio, bulk composition, and level of additive components was investigated. The operating window of bath conditions for void-free electrodeposition was studied in the range of to bulk concentration of additive in a 0.25 M plating solution and for aspect ratios (depth:width) from 0.5 to 4. The mathematical model includes fluid flow, transport by diffusion, migration and convection, multiple species, and reactions in complex geometries. © 2000 The Electrochemical Society. All rights reserved.

NMDA receptor-dependent plasticity of granule cell spiking in the dentate gyrus of normal and epileptic rats.

Because granule cells in the dentate gyrus provide a major synaptic input to pyramidal neurons in the CA3 region of the hippocampus, spike generation by granule cells is likely to have a significant role in hippocampal information processing. Granule cells normally fire in a single-spike mode even when inhibition is blocked and provide single-spike output to CA3 when afferent activity converging into the entorhinal cortex from neocortex, brainstem, and other limbic regions increases. The effects of enhancement of N-methyl-D-aspartate (NMDA) receptor-dependent excitatory synaptic transmission and reduction in gamma-aminobutyric acid-A (GABA(A)) receptor-dependent inhibition on spike generation were examined in granule cells of the dentate gyrus. In contrast to the single-spike mode observed in normal bathing conditions, perforant path stimulation in Mg(2+)-free bathing conditions evoked graded burst discharges in granule cells which increased in duration, amplitude, and number of spikes as a function of stimulus intensity. After burst discharges were evoked during transient exposure to bathing conditions that relieve the Mg(2+) block of the NMDA receptor, there was a marked increase in the NMDA receptor-dependent component of the EPSP, but no significant increase in the non-NMDA receptor-dependent component of the EPSP in normal bathing medium. Supramaximal perforant path stimulation still evoked only a single spike, but granule cell spike generation was immediately converted from a single-spike firing mode to a graded burst discharge mode when inhibition was then reduced. The induction of graded burst discharges in Mg(2+)-free conditions and the expression of burst discharges evoked in normal bathing medium with subsequent disinhibition were both blocked by DL-2-amino-4-phosphonovaleric acid (APV) and were therefore NMDA receptor dependent, in contrast to long-term potentiation (LTP) in the perforant path, which is induced by NMDA receptors and is also expressed by alpha-amino-3-hydroxy-5-methyl-4-isoxazoleproprionate (AMPA) receptors. The graded burst discharge mode was also observed in granule cells when inhibition was reduced after a single epileptic afterdischarge, which enhances the NMDA receptor-dependent component of evoked synaptic response, and in the dentate gyrus reorganized by mossy fiber sprouting in kindled and kainic acid-treated rats. NMDA receptor-dependent plasticity of granule cell spike generation, which can be distinguished from LTP and induces long-term susceptibility to epileptic burst discharge under conditions of reduced inhibition, could modify information processing in the hippocampus and promote epileptic synchronization by increasing excitatory input into CA3.

電析Fe-W合金めっき膜の結晶学的構造と熱平衡状態図との関係

The crystallographic structure and morphology of electrodeposited Fe-W films under different bath conditions were studied in detail by using SEM, XRD and Heat-treatment method. The crystallographic structures of the Fe-W electrodeposits were also compared with the Fe-W thermal equilibrium diagram. The results indicated that the crystallographic structure of electrodeposited Fe-W alloy film gradually changed from microcrystalline to amorphous with increasing W content. The crystallographic structure of the electrodeposited Fe-W alloy film is closely related to its thermal equilibrium diagram, but does not always agree with it.

Effects of bathing and hot footbath on sleep in winter.

The effects of daily bathing and hot footbath (immersion of feet in hot water) in winter on the sleep behavior of nine healthy female volunteers were studied. Subjects were assigned to three sleep conditions: sleep after bathing (Condition B), sleep after hot footbath (Condition F), and sleep without either treatment (Control). Polysomnograms (consisting of electroencephalograph, electrooculograph, and electromyograph) were obtained, and body movements during sleep were measured while monitoring both the rectal and skin temperatures of subjects. In addition, subjective sleep sensations were obtained with a questionnaire answered immediately by the subjects on awakening. The rectal temperature increased by approximately 1.0 degree C under Condition B, but this elevation was not observed under Condition F compared with Control. In contrast, the respective increases in the mean skin temperature of participants subjected to bathing and hot footbath were greater than those of Control, although these temperature differences became negligible 2 h after subjects went to bed. The sleep onset latency was shortened under both conditions compared with Control. Body movements during the first 30 min of sleep in Control were greater than under the other conditions. Rapid eye movement (REM) sleep decreased under Condition B compared with Condition F, and stage 3 was greater under the latter condition compared with Control. As such, the subjective sleep sensations were better under the two treatment conditions. These results suggest that both daily bathing and hot footbath before sleeping facilitates earlier sleep onset. A hot footbath is especially recommendable for the handicapped, elderly, and disabled, who are unable to enjoy regular baths easily and safely.

Structure and Function of Ferricyanide in the Formation of Chromate Conversion Coatings on Aluminum Aircraft Alloy

Raman and infrared spectroscopy were used to determine the structure of and its reaction products in chromate conversion coatings (CCCs) on AA 2024-T3 aluminum aircraft alloy. In addition, Raman spectroscopy was used to monitor CCC growth rates and their dependence on coating bath composition. The IR and Raman spectra of the air‐dried CCC corresponded to those of Berlin green, a polymer, and physisorbed on . No other cyano‐containing products were observed. When was excluded from the coating bath, CCC formation rate greatly decreased. In addition, it was observed that could rapidly oxidize AA 2024-T3, and rapidly reduced Cr(VI) in bath conditions. These results indicate a redox mediation action for , which greatly increases the reduction of Cr(VI) to Cr(III) by the alloy. This process is normally quite slow, and redox mediation by is critical to CCC formation. could substitute for to produce a chromate film with properties very similar to a conventional CCC. The results establish redox mediation as the mechanism of acceleration of CCC formation, but provide no evidence for any additional role of in corrosion protection. © 1999 The Electrochemical Society. All rights reserved.

Modeling Epithelial Cell Homeostasis: Steady-state Analysis

Critical to epithelial cell viability is the homeostasis of cell volume and composition during changes in transcellular transport. In this study, two previously developed mathematical models (principal cell of the collecting duct and proximal tubule cell) are approximated by their linearizations about a reference condition. This yields matrices which estimate cell volume, cell composition, and transcellular fluxes in response to perturbations of bath conditions and membrane transporter activity. These approximations are themselves extended with the inclusion of linear dependence of membrane transport coefficients on cell variables (e.g., volume, solute concentrations, or electrical potential). This provides cell models with variable permeabilities, which may be homeostatic, and which can be examined systematically: sequentially testing each membrane permeability and its controlling cell variable. In the proximal tubule approximation, volume-mediated increases in peritubular K–Cl or Na–3HCO3cotransport, and volume-mediated decreases in Na,K-ATPase activity are homeostatic; modulation of peritubular K permeability has little impact. In the principal cell model, volume homeostasis is afforded by volume-sensitive peritubular Na/H exchange or Cl−conductance. Predictions from the linear analysis are confirmed in the full models. This approach yields a systematic examination of homeostasis in an epithelial model, and identifies candidate control parameters.

Considerations of Hydration-rind Dating of Glass Artefacts: Alteration Morphologies and Experimental Evidence of Hydrogeochemical Soil-zone Pore Water Control

SEM-EDAX textural-chemical alteration morphologies of man-made glass from Egypt and modern soda lime glass are compared to literature data for obsidian and sideromelane (rhyolitic and basaltic glass).A series of laboratory experiments using soda lime glass slides held at 90°C for 3–21 days in baths using different salt solutions (MgCl2, LiCl, NaCl, CaCl2and KCl) in various concentrations provides compelling evidence that for any particular glass composition the style of glass corrosion (hydration–dissolution) is dependent on solution geochemistry. Two fundamental styles of glass corrosion occur: pitting dissolution, and gel-lamination hydration. Glasses of different compositions may behave differently in similar anthrosols. Reaction style and kinetics, and hydration–dissolution rates are controlled by soil temperature, glass and soil water geochemistry, and ultimately alkali exchange between the glass artefact and the soil-zone pore water.Glass and gel thickness loss through dissolution reactions may compromise hydration dating and may be responsible for a variety of reported apparent chronological inconsistencies. Future studies with obsidian and sideromelane under bath conditions and in the natural environment are needed to assess their response to variable soil-zone solution geochemistry.

PVDF membrane formation by diffusion-induced phase separation-morphology prediction based on phase behavior and mass transfer modeling

The equilibrium phase behavior of water (nonsolvent)-DMF (solvent)-PVDF system at 25°C was investigated via both theoretical and experimental approaches. Using binary interaction parameters, χij, obtained previously, the theoretical phase boundaries were computed and were found to match closely the measured binodal and crystallization-induced gelation data. Membranes were prepared using the isothermal immersion-precipitation processes in various dope and bath conditions. The formed membranes demonstrated a broad spectrum of morphologies: At one extreme, asymmetric structure was obtained featuring a continuous tight skin and a sublayer composed of parallel macrovoids and cellular pores; at the other limit, skinless microporous membrane was produced with spherical particles packed into a bi-continuous structure. The crystalline characters of PVDF gels and membranes were examined by small angle light scattering, scanning electron microscopy, and differential scanning calorimetry techniques. In addition, diffusion trajectories and concentration profiles in the membrane solution before precipitation were calculated for the immersion process. These results predicted reasonably the various morphologies observed in the membranes. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 2079–2092, 1999

Tip heater for minimum quench energy measurements on superconducting strands

Superconducting strands can be characterized by their minimum quench energy (MQE), i.e. the minimum heat pulse needed to trigger a quench in operation conditions (field, temperature, current), in the limit of a (temporally and spatially) /spl delta/-shaped disturbance. The sub-mm//spl mu/s range of perturbation space has only been achieved using the electrical graphite-paste heater technique. The present work has put this technique into practice for the strands of the LHC main magnets, which are designed to operate at 1.9 K in peak fields of up to 9 T. No way has been found yet to calibrate MQE measurements. To make relative statements on the MQE of different samples possible, the reproducibility of the measurements was emphasized. First heater prototypes did not come up to this stipulation. Finally the tip-heater configuration was found to meet the requirements. It generates a heat pulse in a thin resistive graphite paste deposit on top of a small tip that is pressed against the sample with a clamp. The clamp guarantees a maximum of exposure of the sample to the surrounding cryogen. The most striking aspect of repeated measurements on a reference sample is that in open bath conditions the MQE as a function of transport current in subcooled helium can reach hundred times the corresponding value in adiabatic conditions (i.e. with the sample potted in a low conductivity medium). This extraordinary cooling performance of superfluid helium, predicted by many has rarely been shown in superconductor stability experiments.