Controlled release of silyl ether camptothecin from thiol-ene click chemistry-functionalized mesoporous silica nanoparticles.

PubMed

Yan, Yue; Fu, Jie; Wang, Tianfu; Lu, Xiuyang

2017-03-15

As efficient drug carriers, stimuli-responsive mesoporous silica nanoparticles are at the forefront of research on drug delivery systems. An acid-responsive system based on silyl ether has been applied to deliver a hybrid prodrug. Thiol-ene click chemistry has been successfully utilized for tethering this prodrug to mesoporous silica nanoparticles. Here, by altering the steric bulk of the substituent on the silicon atom, the release rate of a model drug, camptothecin, was controlled. The synthesized drug delivery system was investigated by analytical methods to confirm the functionalization and conjugation of the mesoporous silica nanoparticles. Herein, trimethyl silyl ether and triethyl silyl ether were selected to regulate the release rate. Under normal plasma conditions (pH 7.4), both types of camptothecin-loaded mesoporous silica nanoparticles (i.e., MSN-Me-CPT and MSN-Et-CPT) did not release the model drug. However, under in vitro acidic conditions (pH 4.0), based on a comparison of the release rates, camptothecin was released from MSN-Me-CPT more rapidly than from MSN-Et-CPT. To determine the biocompatibility of the modified mesoporous silica nanoparticles and the in vivo camptothecin uptake behavior, MTT assays with cancer cells and confocal microscopy observations were conducted, with positive results. These functionalized nanoparticles could be useful in clinical treatments requiring controlled drug release. As the release rate of drug from drug-carrier plays important role in therapy effects, trimethyl silyl ether (TMS) and triethyl silyl ether (TES) were selected as acid-sensitive silanes to control the release rates of model drugs conjugated from MSNs by thiol-ene click chemistry. The kinetic profiles of TMS and TES materials have been studied. At pH 4.0, the release of camptothecin from MSN-Et-CPT occurred after 2h, whereas MSN-Me-CPT showed immediate drug release. The results showed that silyl ether could be used to control release rates of drugs from MSNs under acid environment, which could be useful in clinical treatments requiring controlled drug release. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

The relationship between functional sciatic nerve block duration and the rate of release of lidocaine from a controlled-release matrix.

PubMed

Gerner, Peter; Wang, Chi-Fei; Lee, Byung-Sang; Suzuki, Suzuko; Degirolami, Umberto; Gandhi, Ankur; Knaack, David; Strichartz, Gary

2010-07-01

Nerve blocks of long duration are often desirable in perioperative and postoperative situations. The relationship between the duration of such blocks and the rate at which a local anesthetic is released is important to know for developing a localized drug delivery system that will optimize block duration. Lidocaine concentration was varied in 1 series of formulations (OSB-L) containing a constant amount of release rate modifier. In another series (OST-R), the release rate modifier was varied while the lidocaine content was held constant. Release kinetics were measured in vitro and correlated to the in vivo duration of antinociceptive and motor block effects when the formulation was implanted next to the rat sciatic nerve. In parallel studies, rats receiving different formulations of slow-release lidocaine were fixed by intracardiac perfusion with 4% paraformaldehyde and nerve-muscle tissue taken for histopathological analysis. In this study, we have demonstrated that the most important variable for effecting functional nerve block, i.e., the blockade of impulses in the relevant fibers of the sciatic nerve, is the rate of lidocaine release at that time. For the OSB-L formulations (lidocaine concentrations of 1.875%, 3.75%, 7.5%, and 15% at a constant release rate modifier of 5%), the average in vitro release rates at 50% recovery of motor block and nociceptive block were 0.91 +/- 0.28 and 1.75 +/- 0.61 mg/h, respectively. For the OST-R formulations (16% lidocaine with release rate modifier concentrations of 1.875%, 3.75%, 7.5%, and 15%), the average in vitro release rates at 50% recovery of motor block and nociceptive block were 2.33 +/- 1.39 and 4.34 +/- 1.09 mg/h, respectively. The OSB-L formulations showed a dose-dependent increase in block duration proportional to an increase in initial lidocaine concentration, whereas the OST-R formulations showed a nonmonotonic relationship between release rate modifier concentration and block duration. The histopathological studies at 24 hours, 3, 5, or 7 days, and 4 weeks after the implantation revealed inflammatory reactions with degrees correlated with lidocaine content, but limited to the connective tissue and muscle immediately surrounding the implanted material. Despite these observed inflammatory reactions, nociceptive and motor block function returned to normal, preimplantation values in all animals. Increasing initial lidocaine content proportionately increased the duration of functional sciatic nerve block. However, decreasing the release rate per se does not give a proportional increase in block duration. Instead, there seems to be an optimal, intermediate release rate for achieving the maximum duration of block.

Desorption kinetics of hydrophobic organic chemicals from sediment to water: a review of data and models.

PubMed

Birdwell, Justin; Cook, Robert L; Thibodeaux, Louis J

2007-03-01

Resuspension of contaminated sediment can lead to the release of toxic compounds to surface waters where they are more bioavailable and mobile. Because the timeframe of particle resettling during such events is shorter than that needed to reach equilibrium, a kinetic approach is required for modeling the release process. Due to the current inability of common theoretical approaches to predict site-specific release rates, empirical algorithms incorporating the phenomenological assumption of biphasic, or fast and slow, release dominate the descriptions of nonpolar organic chemical release in the literature. Two first-order rate constants and one fraction are sufficient to characterize practically all of the data sets studied. These rate constants were compared to theoretical model parameters and functionalities, including chemical properties of the contaminants and physical properties of the sorbents, to determine if the trends incorporated into the hindered diffusion model are consistent with the parameters used in curve fitting. The results did not correspond to the parameter dependence of the hindered diffusion model. No trend in desorption rate constants, for either fast or slow release, was observed to be dependent on K(OC) or aqueous solubility for six and seven orders of magnitude, respectively. The same was observed for aqueous diffusivity and sediment fraction organic carbon. The distribution of kinetic rate constant values was approximately log-normal, ranging from 0.1 to 50 d(-1) for the fast release (average approximately 5 d(-1)) and 0.0001 to 0.1 d(-1) for the slow release (average approximately 0.03 d(-1)). The implications of these findings with regard to laboratory studies, theoretical desorption process mechanisms, and water quality modeling needs are presented and discussed.

Report of the River Master of the Delaware River for the period December 1, 1983 - November 30, 1984

USGS Publications Warehouse

Schaefer, F.T.; Harkness, W.E.; Baebenroth, R.W.; Speight, D.W.

1985-01-01

A Decree of the U.S. Supreme Court in 1954 established the position of Delaware River Master. The Decree authorizes diversions of water from the Delaware River basin and requires compensating releases from certain reservoirs of the City of New York to be made under the supervision and direction of the River Master. Reports to the Court, not less frequently than annually were stipulated. During the 1984 report year, December 1, 1983 to November 30, 1984, precipitation and runoff varied from above average to below average in the Delaware River basin. For the year as a whole, precipitation and runoff were near average. Operations were under a status of drought warning December 1, 1983; however, the above normal precipitation the first half of the year increased storage in the reservoirs to record levels by June 1, 1984. Below normal precipitation from August to November coupled with large releases to maintain the Montague flow objective and customary diversions for water supply reduced storage in the reservoirs to the drought-warning level by November 27. Diversions from the Delaware River basin by New York City and New Jersey conformed to the terms of the Amended Decree throughout the year. Releases were made as directed by the River Master at rates designed to meet the Montague flow objective on 127 days between June 23 and November 30. Releases were made at conservation rates or at rates designed to relieve thermal stress in the streams downstream from the reservoirs at other times. (USGS)

Triggered intracellular calcium waves in dog and human left atrial myocytes from normal and failing hearts.

PubMed

Aistrup, Gary L; Arora, Rishi; Grubb, Søren; Yoo, Shin; Toren, Benjamin; Kumar, Manvinder; Kunamalla, Aaron; Marszalec, William; Motiwala, Tej; Tai, Shannon; Yamakawa, Sean; Yerrabolu, Satya; Alvarado, Francisco J; Valdivia, Hector H; Cordeiro, Jonathan M; Shiferaw, Yohannes; Wasserstrom, John Andrew

2017-11-01

Abnormal intracellular Ca2+ cycling contributes to triggered activity and arrhythmias in the heart. We investigated the properties and underlying mechanisms for systolic triggered Ca2+ waves in left atria from normal and failing dog hearts. Intracellular Ca2+ cycling was studied using confocal microscopy during rapid pacing of atrial myocytes (36 °C) isolated from normal and failing canine hearts (ventricular tachypacing model). In normal atrial myocytes (NAMs), Ca2+ waves developed during rapid pacing at rates ≥ 3.3 Hz and immediately disappeared upon cessation of pacing despite high sarcoplasmic reticulum (SR) load. In heart failure atrial myocytes (HFAMs), triggered Ca2+ waves (TCWs) developed at a higher incidence at slower rates. Because of their timing, TCW development relies upon action potential (AP)-evoked Ca2+ entry. The distribution of Ca2+ wave latencies indicated two populations of waves, with early events representing TCWs and late events representing conventional spontaneous Ca2+ waves. Latency analysis also demonstrated that TCWs arise after junctional Ca2+ release has occurred and spread to non-junctional (cell core) SR. TCWs also occurred in intact dog atrium and in myocytes from humans and pigs. β-adrenergic stimulation increased Ca2+ release and abolished TCWs in NAMs but was ineffective in HFAMs making this a potentially effective adaptive mechanism in normals but potentially arrhythmogenic in HF. Block of Ca-calmodulin kinase II also abolished TCWs, suggesting a role in TCW formation. Pharmacological manoeuvres that increased Ca2+ release suppressed TCWs as did interventions that decreased Ca2+ release but these also severely reduced excitation-contraction coupling. TCWs develop during the atrial AP and thus could affect AP duration, producing repolarization gradients and creating a substrate for reentry, particularly in HF where they develop at slower rates and a higher incidence. TCWs may represent a mechanism for the initiation of atrial fibrillation particularly in HF. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions please email: journals.permissions@oup.com.

Effects of nutrient enrichment on the release of dissolved organic carbon and nitrogen by the scleractinian coral Montipora digitata

NASA Astrophysics Data System (ADS)

Tanaka, Y.; Ogawa, H.; Miyajima, T.

2010-09-01

The effects of nutrient enrichment on the release of dissolved organic carbon and nitrogen (DOC and DON, respectively) from the coral Montipora digitata were investigated in the laboratory. Nitrate (NO3 -) and phosphate (PO4 3-) were supplied to the aquarium to get the final concentrations of 10 and 0.5 μmol l-1, respectively, and the corals were incubated for 8 days. The release rate of DON per unit coral surface area significantly decreased after the nutrient enrichment, while the release rate of DOC was constant. Because the chlorophyll a (chl a) content of zooxanthellae per unit surface area increased, the release rate of DOC significantly decreased when normalized to unit chl a. These results suggested that the incorporation of NO3 - and PO4 3- stimulated the synthesis of new cellular components in the coral colonies and consequently, reduced extracellular release of DOC and DON. Actually, significant increase in N and P contents relative to C content was observed in the coral’s tissue after the nutrient enrichment. The present study has concluded that inorganic nutrient enrichment not only affects coral-algal metabolism inside the colony but also affects a microbial community around the coral because the organic matter released from corals functions as energy carrier in the coral reef ecosystem.

Calcium released by photolysis of DM-nitrophen stimulates transmitter release at squid giant synapse.

PubMed

Delaney, K R; Zucker, R S

1990-07-01

1. Transmitter release at the squid giant synapse was stimulated by photolytic release of Ca2+ from the 'caged' Ca2+ compound DM-nitrophen (Kaplan & Ellis-Davies, 1988) inserted into presynaptic terminals. 2. Competing binding reactions cause the amount of Ca2+ released by DM-nitrophen photolysis to depend on the concentrations of DM-nitrophen, total Ca2+, Mg+, ATP and native cytoplasmic Ca2+ buffer. Measurements of presynaptic [Ca2+] changes by co-injection of the fluorescent indicator dye Fura-2 show that DM-nitrophen photolysis causes a transient rise in Ca2+ followed by decay within about 150 ms to an increased steady-state level. 3. Rapid photolysis of Ca2(+)-loaded nitrophen within the presynaptic terminal was followed in less than a millisecond by depolarization of the postsynaptic membrane. As with action potential-evoked excitatory postsynaptic potentials (EPSPs), the light-evoked response was partially and reversibly blocked by 1-3 mM-kainic acid which desensitizes postsynaptic glutamate receptors. 4. Release was similar in magnitude and rate to normal action potential-mediated EPSPs. 5. The release of transmitter by photolysis of Ca2(+)-loaded DM-nitrophen was not affected by removal of Ca2+ from the saline or addition of tetrodotoxin. Photolysis of DM-nitrophen injected into presynaptic terminals without added Ca2+ did not stimulate release of transmitter nor did it interfere with normal action potential-mediated release. 6. Stimulation of presynaptic action potentials in Ca2(+)-free saline during the light-evoked response did not elicit increased release of transmitter if the ganglion was bathed in Ca2(+)-free saline, i.e. in the absence of Ca2+ influx. Increasing the intensity of the light or stimulating presynaptic action potentials in Ca2(+)-containing saline increased the release of transmitter. Therefore the failure of presynaptic voltage change to increase transmitter release resulting from release of caged Ca2+ was not due to saturation or inhibition of the release mechanism by light-released Ca2+. 7. Decreasing the temperature of the preparation increased the delay to onset of the light-evoked response and reduced its amplitude and rate of rise to an extent similar to that observed for action potential-evoked EPSPs.

Dynamic leaching studies of 48 MWd/kgU UO2 commercial spent nuclear fuel under oxic conditions

NASA Astrophysics Data System (ADS)

Serrano-Purroy, D.; Casas, I.; González-Robles, E.; Glatz, J. P.; Wegen, D. H.; Clarens, F.; Giménez, J.; de Pablo, J.; Martínez-Esparza, A.

2013-03-01

The leaching of a high-burn-up spent nuclear fuel (48 MWd/KgU) has been studied in a carbonate-containing solution and under oxic conditions using a Continuously Stirred Tank Flow-Through Reactor (CSTR). Two samples of the fuel, one prepared from the centre of the pellet (labelled CORE) and another one from the fuel pellet periphery, enriched with the so-called High Burn-Up Structure (HBS, labelled OUT) have been used.For uranium and actinides, the results showed that U, Np, Am and Cm gave very similar normalized dissolution rates, while Pu showed slower dissolution rates for both samples. In addition, dissolution rates were consistently two to four times lower for OUT sample compared to CORE sample.Considering the fission products release the main results are that Y, Tc, La and Nd dissolved very similar to uranium; while Cs, Sr, Mo and Rb have up to 10 times higher dissolution rates. Rh, Ru and Zr seemed to have lower dissolution rates than uranium. The lowest dissolution rates were found for OUT sample.Three different contributions were detected on uranium release, modelled and attributed to oxidation layer, fines and matrix release.

Turbulence-flame interactions in DNS of a laboratory high Karlovitz premixed turbulent jet flame

NASA Astrophysics Data System (ADS)

Wang, Haiou; Hawkes, Evatt R.; Chen, Jacqueline H.

2016-09-01

In the present work, direct numerical simulation (DNS) of a laboratory premixed turbulent jet flame was performed to study turbulence-flame interactions. The turbulent flame features moderate Reynolds number and high Karlovitz number (Ka). The orientations of the flame normal vector n, the vorticity vector ω and the principal strain rate eigenvectors ei are examined. The in-plane and out-of-plane angles are introduced to quantify the vector orientations, which also measure the flame geometry and the vortical structures. A general observation is that the distributions of these angles are more isotropic downstream as the flame and the flow become more developed. The out-of-plane angle of the flame normal vector, β, is a key parameter in developing the correction of 2D measurements to estimate the corresponding 3D quantities. The DNS results show that the correction factor is unity at the inlet and approaches its theoretical value of an isotropic distribution downstream. The alignment characteristics of n, ω and ei, which reflect the interactions of turbulence and flame, are also studied. Similar to a passive scalar gradient in non-reacting flows, the flame normal has a tendency to align with the most compressive strain rate, e3, in the flame, indicating that turbulence contributes to the production of scalar gradient. The vorticity dynamics are examined via the vortex stretching term, which was found to be the predominant source of vorticity generation balanced by dissipation, in the enstrophy transport equation. It is found that although the vorticity preferentially aligns with the intermediate strain rate, e2, the contribution of the most extensive strain rate, e1, to vortex stretching is comparable with that of the intermediate strain rate, e2. This is because the eigenvalue of the most extensive strain rate, λ1, is always large and positive. It is confirmed that the vorticity vector is preferentially positioned along the flame tangential plane, contributing to the dominance of cylindrical curvature of the flame front. Finally, the effect of heat release on the turbulence-flame interactions is examined. It is found that heat release has only limited impact on the statistics due to the minor role played by the strain rate induced by heat release rate in the current high Ka flame.

Strain energy release rate as a function of temperature and preloading history utilizing the edge delamination fatique test method

NASA Technical Reports Server (NTRS)

Zimmerman, Richard S.; Adams, Donald F.

1989-01-01

Static laminate and tension-tension fatigue tests of IM7/8551-7 composite materials was performed. The Edge Delamination Test (EDT) was utilized to evaluate the temperature and preloading history effect on the critical strain energy release rate. Static and fatigue testing was performed at room temperature and 180 F (82 C). Three preloading schemes were used to precondition fatigue test specimens prior to performing the normal tension-tension fatigue EDT testing. Computer software was written to perform all fatigue testing while monitoring the dynamic modulus to detect the onset of delamination and record the test information for later retrieval and reduction.

Preparation and In Vitro/In Vivo Evaluation of Vinpocetine Elementary Osmotic Pump System

PubMed Central

Ning, Meiying; Zhou, Yue; Chen, Guojun; Mei, Xingguo

2011-01-01

Preparation and in vitro and in vivo evaluation of vinpocetine (VIN) elementary osmotic pump (EOP) formulations were investigated. A method for the preparation of VIN elementary osmotic pump tablet was obtained by adding organic acid additives to increase VIN solubility. VIN was used as the active pharmaceutical ingredient, lactose and mannitol as osmotic agent. Citric acid was used as increasing API solubility and without resulting in the API degradation. It is found that the VIN release rate was increasing with the citric acid amount at a constant range. Cellulose acetate 398-3 was employed as semipermeable membrane containing polyethylene glycol 6000 and diethyl-o-phthalate as pore-forming agent and plasticizer for controlling membrane permeability. In addition, a clear difference between the pharmacokinetic patterns of VIN immediate release and VIN elementary osmotic pump formulations was revealed. The area under the plasma concentration-time curve after oral administration of elementary osmotic pump formulations was equivalent to VIN immediate release formulation. Furthermore, significant differences found for mean residence time, elimination half-life, and elimination rate constant values corroborated prolonged release of VIN from elementary osmotic pump formulations. These results suggest that the VIN osmotic pump controlled release tablets have marked controlled release characters and the VIN osmotic pump controlled release tablets and the normal tablets were bioequivalent. PMID:21577257

A new tracer experiment to estimate the methane emissions from a dairy cow shed using sulfur hexafluoride (SF6)

NASA Astrophysics Data System (ADS)

Marik, Thomas; Levin, Ingeborg

1996-09-01

Methane emission from livestock and agricultural wastes contribute globally more than 30% to the anthropogenic atmospheric methane source. Estimates of this number have been derived from respiration chamber experiments. We determined methane emission rates from a tracer experiment in a modern cow shed hosting 43 dairy cows in their accustomed environment. During a 24-hour period the concentrations of CH4, CO2, and SF6, a trace gas which has been released at a constant rate into the stable air, have been measured. The ratio between SF6 release rate and measured SF6 concentration was then used to estimate the ventilation rate of the stable air during the course of the experiment. The respective ratio between CH4 or CO2 and SF6 concentration together with the known SF6 release rate allows us to calculate the CH4 (and CO2) emissions in the stable. From our experiment we derive a total daily mean CH4 emission of 441 LSTP per cow (9 cows nonlactating), which is about 15% higher than previous estimates for German cows with comparable milk production obtained during respiration chamber experiments. The higher emission in our stable experiment is attributed to the contribution of CH4 release from about 50 m3 of liquid manure present in the cow shed in underground channels. Also, considering measurements we made directly on a liquid manure tank, we obtained an estimate of the total CH4 production from manure: The normalized contribution of methane from manure amounts to 12-30% of the direct methane release of a dairy cow during rumination. The total CH4 release per dairy cow, including manure, is 521-530 LSTP CH4 per day.

Crustacean zooplankton release copious amounts of dissolved organic matter as taurine in the ocean.

PubMed

Clifford, Elisabeth L; Hansell, Dennis A; Varela, Marta M; Nieto-Cid, Mar; Herndl, Gerhard J; Sintes, Eva

2017-11-01

Taurine (Tau), an amino acid-like compound, is present in almost all marine metazoans including crustacean zooplankton. It plays an important physiological role in these organisms and is released into the ambient water throughout their life cycle. However, limited information is available on the release rates by marine organisms, the concentrations and turnover of Tau in the ocean. We determined dissolved free Tau concentrations throughout the water column and its release by abundant crustacean mesozooplankton at two open ocean sites (Gulf of Alaska and North Atlantic). At both locations, the concentrations of dissolved free Tau were in the low nM range (up to 15.7 nM) in epipelagic waters, declining sharply in the mesopelagic to about 0.2 nM and remaining fairly stable throughout the bathypelagic waters. Pacific amphipod-copepod assemblages exhibited lower dissolved free Tau release rates per unit biomass (0.8 ± 0.4 μmol g -1 C-biomass h -1 ) than Atlantic copepods (ranging between 1.3 ± 0.4 μmol g -1 C-biomass h -1 and 9.5 ± 2.1 μmol g -1 C-biomass h -1 ), in agreement with the well-documented inverse relationship between biomass-normalized excretion rates and body size. Our results indicate that crustacean zooplankton might contribute significantly to the dissolved organic matter flux in marine ecosystems via dissolved free Tau release. Based on the release rates and assuming steady state dissolved free Tau concentrations, turnover times of dissolved free Tau range from 0.05 d to 2.3 d in the upper water column and are therefore similar to those of dissolved free amino acids. This rapid turnover indicates that dissolved free Tau is efficiently consumed in oceanic waters, most likely by heterotrophic bacteria.

Inlay osmotic pump tablets containing metformin and glipizide.

PubMed

Patel, R B; Patel, G N; Patel, H R; Patel, M M

2011-10-01

The goal of diabetes therapy today is to achieve and maintain as near normal glycemia as possible to prevent the long-term microvascular and macrovascular complications of an elevated blood glucose. A newly developed inlay osmotic pump tablet (IOPT) can deliver glipizide (GLZ) and metformin HCl (MET) gradually in controlled manner. The aim of present investigation was to prepare the IOPT that can deliver >75% of GLZ in 2 h, whereas MET released after 2 h and sustained up to 12 h. In the present work, HP-β-CD was used to modify the solubility of GLZ before incorporating in the osmotic system and MET was spray-dried with HPMC A15C to modify its release profile, flow property, and compressibility. Various parameters mainly G(75%) (75% GLZ release), t(LMET) (lag time of MET release from device), Q(10 h) (percent of MET released within 10 h), and RSQ(ZERO) (R(2) of release data fitted to zero-order equation) were used to compare different formulations. The effects of different formulation variables, that is, osmagents, concentration of hydrophilic polymer, diameter of drug releasing orifice, and coating composition on the drug release profile were investigated. The release rate of GLZ could be effectively modified by the addition of sodium carbonate and sodium chloride, whereas the release rate of MET was adjusted by dual-coating system and by addition of hydrophilic polymer. The developed inlay osmotic system could be effective in the multidrug therapy of diabetes by delivering both drugs in a controlled manner.

Experimental study of terrestrial plant litter interaction with aqueous solutions

NASA Astrophysics Data System (ADS)

Fraysse, F.; Pokrovsky, O. S.; Meunier, J.-D.

2010-01-01

Quantification of silicon and calcium recycling by plants is hampered by the lack of physico-chemical data on reactivity of plant litter in soil environments. We applied a laboratory experimental approach for determining the silica and calcium release rates from litter of typical temperate and boreal plants: pine ( Pinus laricio), birch ( Betula pubescens), larch ( Larix gmelinii), elm ( Ulmus laevis Pall.), tree fern ( Dicksonia squarrosa), and horsetail (Equisetum arvense) in 0.01 M NaCl solutions, pH of 2-10 and temperature equals to 5, 25 and 40 °C. Open system, mixed-flow reactors equipped with dialysis compartment and batch reactors were used. Comparative measurements were performed on intact larch needles and samples grounded during different time, sterilized or not and with addition or not of sodium azide in order to account for the effect of surface to mass ratio and possible microbiological activity on the litter dissolution rates. Litter degradation results suggest that the silica release rate is independent on dissolved organic carbon release (cell breakdown) which implies the presence of phytoliths in a pure "inorganic" pool not complexed with organic matter. Calcium and DOC are released at the very first stage of litter dissolution while Si concentration increases gradually suggesting the presence of Ca and Si in two different pools. The dry-weight normalized dissolution rate at circum-neutral pH range (approx. 1-10 μmol/g DW/day) is 2 orders of magnitude higher than the rates of Si release from common soil minerals (kaolinite, smectite, illite). Minimal Ca release rates evaluated from batch and mixed-flow reactors are comparable with those of most reactive soil minerals such as calcite and apatite, and several orders of magnitude higher than the dissolution rates of major rock-forming silicates (feldspars, pyroxenes). The activation energy for Si liberation from plant litter is approx. 50 kJ/mol which is comparable with that of surface-controlled mineral dissolutions. It is shown that the Si release rate from the above-ground forest biomass is capable of producing the Si concentrations observed in soil solutions of surficial horizons and contribute significantly to the Si flux from the soil to the river.

Masking release for words in amplitude-modulated noise as a function of modulation rate and task

PubMed Central

Buss, Emily; Whittle, Lisa N.; Grose, John H.; Hall, Joseph W.

2009-01-01

For normal-hearing listeners, masked speech recognition can improve with the introduction of masker amplitude modulation. The present experiments tested the hypothesis that this masking release is due in part to an interaction between the temporal distribution of cues necessary to perform the task and the probability of those cues temporally coinciding with masker modulation minima. Stimuli were monosyllabic words masked by speech-shaped noise, and masker modulation was introduced via multiplication with a raised sinusoid of 2.5–40 Hz. Tasks included detection, three-alternative forced-choice identification, and open-set identification. Overall, there was more masking release associated with the closed than the open-set tasks. The best rate of modulation also differed as a function of task; whereas low modulation rates were associated with best performance for the detection and three-alternative identification tasks, performance improved with modulation rate in the open-set task. This task-by-rate interaction was also observed when amplitude-modulated speech was presented in a steady masker, and for low- and high-pass filtered speech presented in modulated noise. These results were interpreted as showing that the optimal rate of amplitude modulation depends on the temporal distribution of speech cues and the information required to perform a particular task. PMID:19603883

Measurement of /sup 14/C emission rates from a pressurized heavy water reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joshi, M.L.; Ramamirtham, B.; Soman, S.D.

Carbon-14 is produced in pressurized heavy water reactors (PHWR), mainly as an activation product in the fuel. It is also produced in the heavy water used as the primary coolant and moderator, and is produced in the air in the annular space between the pressure tube and calandria tubes as well as in the free space in the calandria vault. The production rates in different systems of a PHWR are calculated on the basis of design parameters. During a period of 3 y, /sup 14/C released through the gaseous route has been measured at Rajasthan Atomic Power Station, Kota, India,more » a PHWR unit. These releases have been found to be mainly /sup 14/CO/sub 2/. This reduced form of /sup 14/C is less than 5% of the releases. The normalized releases of /sup 14/C have a geometric mean of 5.17 TBq GWe-1 y-1 and a geometric standard deviation of 1.52. The /sup 14/C present in the form of carbonates in liquid effluents has also been measured and is 0.14% of the gaseous releases.« less

Delamination micromechanics analysis

NASA Technical Reports Server (NTRS)

Adams, D. F.; Mahishi, J. M.

1985-01-01

A three-dimensional finite element analysis was developed which includes elastoplastic, orthotropic material response, and fracture initiation and propagation. Energy absorption due to physical failure processes characteristic of the heterogeneous and anisotropic nature of composite materials is modeled. A local energy release rate in the presence of plasticity was defined and used as a criterion to predict the onset and growth of cracks in both micromechanics and macromechanics analyses. This crack growth simulation technique is based upon a virtual crack extension method. A three-dimensional finite element micromechanics model is used to study the effects of broken fibers, cracked matrix and fiber-matrix debond on the fracture toughness of the unidirectional composite. The energy release rates at the onset of unstable crack growth in the micromechanics analyses are used as critical energy release rates in the macromechanics analysis. This integrated micromechanical and macromechanical fracture criterion is shown to be very effective in predicting the onset and growth of cracks in general multilayered composite laminates by applying the criterion to a single-edge notched graphite/epoxy laminate subjected to implane tension normal to the notch.

Report of the River Master of the Delaware River for the period December 1, 1984 - November 30, 1985

USGS Publications Warehouse

Schaefer, F.T.; Harkness, W.E.; Cecil, L.D.

1986-01-01

A Decree of the Supreme Court of the United States in 1954 established the position of Delaware River Master. The Decree authorizes diversions of water from the Delaware River basin and requires compensating releases from certain reservoirs of the City of New York to be made under the supervision and direction of the River Master. Reports to the Court, not less frequently than annually, were stipulated. During the 1985 report year, December 1, 1984, to November 30, 1985, precipitation and runoff varied from below average to above average in the Delaware River basin. For the year as a whole, precipitation was near average. Runoff was below average. Operations were under a status of drought warning or drought from January 23, 1984, through the end of the report year. Below-normal precipitation the first half of the year resulted in decreased storage in the reservoirs to record low levels by March 1, 1985. Storage remained at record low levels from March through September. Above-normal precipitation in September and November served to break the drought and increase storage into the normal zone of the operating curves for the reservoirs. Diversions from the Delaware River basin by New York City did not exceed those authorized by the terms of the Amended Decree or those invoked by the several emergency conservation measures throughout the year. There were no diversions from the Delaware River basin by New Jersey during the year. Releases were made as directed by the River Master at rates designed to meet the Montague flow objective on 82 days between June 14 and September 28. Releases were made at conservation rates or at rates designed to relieve thermal stress in the streams downstream from the reservoirs at other times. (See also W89-04133) (USGS)

[Harvest of the carbon source in wastewater by the adsorption and desorption of activated sludge].

PubMed

Liu, Hong-Bo; Wen, Xiang-Hua; Zhao, Fang; Mei, Yi-Jun

2011-04-01

The carbon source in municipal wastewater was adsorbed by activated sludge and then harvested through the hydrolysis of activated sludge. Results indicated that activated sludge had high absorbing ability towards organic carbon and phosphorus under continuous operation mode, and the average COD and TP absorption rate reached as high as 63% and 76%, respectively. Moreover, about 50% of the soluble carbon source was outside of the sludge cell and could be released under mild hydrolysis condition. Whereas the absorbed amount of nitrogen was relatively low, and the removal rate of ammonia was only 13% . Furthermore, the releases of organic carbon, nitrogen and phosphorus from the sludge absorbing pollutants in the wastewater were studied. By comparing different hydrolysis conditions of normal (pH 7.5, 20 degrees C), heating (pH 7.5, 60 degrees C) and the alkaline heating (pH 11, 60 degrees C), the last one presented the optimum hydrolysis efficiency. Under which, the release rate of COD could reach 320 mg/g after 24 hours, whereas nitrogen and phosphorus just obtained low release rates of 18 mg/g and 2 mg/g, respectively. Results indicate that the carbon source in wastewater could be harvested by the adsorption and desorption of activated sludge, and the concentrations of nitrogen and phosphorus are low and would not influence the reuse of the harvested carbon source.

The Role of Neural Reflexes in Control of the Cardiovascular System during Stress.

DTIC Science & Technology

1984-02-01

cold block increase arterial pressure but did not alter plasma renin activity or renin secretory rate in dogs with normal or high sodium diet...also found that these afferents may play a keen role in the regulation of renin scretoary rate during conditions which may alter cardiopulmonary blood ...important hormone in -. the regulation of arterial pressure . However, the role of the nervous system in controlling the release of vasopressin has not been

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wolfe, R.R.; Peters, E.J.; Klein, S.

In this study the rate of lipolysis (fatty acid and glycerol release into blood) has been quantified in both normal weight and obese volunteers after both 15 and 87 h of fasting. In each study, the basal rate and subsequent response to epinephrine infusion were determined. The rate of appearance (R/sub a/) of free fatty acids (FFA) and glycerol were quantified by infusion of (1- TC)palmitate and D-5-glycerol, respectively. Substrate flux rates per unit of body fat mass and lean body mass were calculated from total body water measurements using H2 YO dilution. In normal volunteers, the basal R/sub a/more » FFA and R/sub a/ glycerol rose markedly with 87 h of fasting, whereas the increases were more modest in the obese subjects. However, the rate of mobilization of fat, in relation to the lean body mass, was higher in the obese subjects than in the normal subjects after 15 h of fasting, and the values were similar in both groups after 87 h of fasting. There was an increased lipolytic response to epinephrine after fasting in both groups. This increased sensitivity may have resulted from the enhancement of fatty acid-triglyceride substrate cycling that occurred after fasting.« less

Acoustic properties of naturally produced clear speech at normal speaking rates

NASA Astrophysics Data System (ADS)

Krause, Jean C.; Braida, Louis D.

2004-01-01

Sentences spoken ``clearly'' are significantly more intelligible than those spoken ``conversationally'' for hearing-impaired listeners in a variety of backgrounds [Picheny et al., J. Speech Hear. Res. 28, 96-103 (1985); Uchanski et al., ibid. 39, 494-509 (1996); Payton et al., J. Acoust. Soc. Am. 95, 1581-1592 (1994)]. While producing clear speech, however, talkers often reduce their speaking rate significantly [Picheny et al., J. Speech Hear. Res. 29, 434-446 (1986); Uchanski et al., ibid. 39, 494-509 (1996)]. Yet speaking slowly is not solely responsible for the intelligibility benefit of clear speech (over conversational speech), since a recent study [Krause and Braida, J. Acoust. Soc. Am. 112, 2165-2172 (2002)] showed that talkers can produce clear speech at normal rates with training. This finding suggests that clear speech has inherent acoustic properties, independent of rate, that contribute to improved intelligibility. Identifying these acoustic properties could lead to improved signal processing schemes for hearing aids. To gain insight into these acoustical properties, conversational and clear speech produced at normal speaking rates were analyzed at three levels of detail (global, phonological, and phonetic). Although results suggest that talkers may have employed different strategies to achieve clear speech at normal rates, two global-level properties were identified that appear likely to be linked to the improvements in intelligibility provided by clear/normal speech: increased energy in the 1000-3000-Hz range of long-term spectra and increased modulation depth of low frequency modulations of the intensity envelope. Other phonological and phonetic differences associated with clear/normal speech include changes in (1) frequency of stop burst releases, (2) VOT of word-initial voiceless stop consonants, and (3) short-term vowel spectra.

Postrelease monitoring of radio-instrumented sea otters in Prince William Sound

USGS Publications Warehouse

Monnett, C.; Rotterman, L.M.; Stack, C.; Monson, Daniel H.; Bayha, Keith; Kormendy, Jennifer

1990-01-01

Sea otters (Enhydra lutris) that were captured in western Prince William Sound (PWS) or the Gulf of Alaska, treated, and held in captivity at the temporary rehabilitation centers established in response to the T/V Exxon Valdez oil spill were instrumented with radio transmitters, released into eastern PWS, and monitored by radiotelemetry. We undertook the present study to gain information for guiding the release of the remaining captive otters and evaluating the efficacy of sea otter rehabilitation after exposure to crude oil. Radio transmitters were attached to the flippers of seven sea otters released in May 1989 and monitored for periods of a few hours to more than 60 days. However, little was learned about the fate of these animals because the radio transmitters used proved unreliable. Forty-five additional sea otters from the rehabilitation centers were implanted with radio transmitters, released into northeastern PWS and monitored for 8 months. During the first 20 days after the first release of these implanted otters (n = 21), they were more mobile than wild-caught and released sea otters studied in PWS, from 1984 through 1990. All were alive and vigorous at the end of the 20-day period. Tracking of all 45 implanted sea otters during the 8-month period showed that the otters remained highly mobile. Many (46.6%) crossed into western PWS. However, by the end of the 8 months, 12 of the instrumented otters were dead and 9 were missing. One radio failed. These mortality and missing rates are much higher than those normally observed for adult sea otters in PWS. The death rate was highest in winter. These data suggest that, despite the tremendous amount of money and energy directed toward the treatment and care of these animals, the sea otters released from the centers were not completely rehabilitated, that is, not returned to a normal state. We recommend that future policies focus on preventing otters from becoming oiled, rather than attempting to treat them after oiling has occurred. This focus is especially recommended because of stress and disease risks associated with bringing wild animals into captivity.

Correction of the mineralization defect in hyp mice treated with protease inhibitors CA074 and pepstatin

PubMed Central

Rowe, Peter S.N.; Matsumoto, Naoko; Jo, Oak D.; Shih, Remi N.J.; Oconnor, Jeannine; Roudier, Martine P.; Bain, Steve; Liu, Shiguang; Harrison, Jody; Yanagawa, Norimoto

2012-01-01

Increased expression of several osteoblastic proteases and MEPE (a bone matrix protein) occurs in X-linked hypophosphatemic rickets (hyp). This is associated with an increased release of a protease-resistant MEPE peptide (ASARM peptide), a potent inhibitor of mineralization. Cathepsin B cleaves MEPE releasing ASARM peptide and hyp osteoblast/osteocyte cells hypersecrete cathepsin D, an activator of cathepsin B. Our aims were to determine whether cathepsin inhibitors correct the mineralization defect in vivo and whether hyp-bone ASARM peptide levels are reduced after protease treatment. Normal littermates and hyp mice (n = 6) were injected intraperitoneally once a day for 4 weeks with pepstatin, CAO74 or vehicle. Animals were then sacrificed and bones plus serum removed for comprehensive analysis. All hyp mice groups (treated and untreated) remained hypophosphatemic with serum 1,25 vitamin D3 inappropriately normal. Serum PTH was significantly elevated in all hyp mice groups relative to normal mice (P = 0.0017). Untreated hyp mice had six-fold elevated levels of serum alkaline-phosphatase and two-fold elevated levels of ASARM peptides relative to normal mice (P < 0.001). In contrast, serum alkaline phosphatase and serum ASARM peptides were significantly reduced (normalized) in hyp mice treated with CA074 or pepstatin. Serum FGF23 levels remained high in all hyp animal groups (P < 0.0001). Hyp mice treated with protease inhibitors showed dramatic reductions in unmineralized osteoid (femurs) compared to control hyp mice (Goldner staining). Also, hyp animals treated with protease inhibitors showed marked and significant improvements in growth plate width (42%), osteoid thickness (40%) and cortical area (40%) (P < 0.002). The mineralization apposition rate, bone formation rate and mineralization surface were normalized by protease-treatment. High-resolution pQCT mineral histomorphometry measurements and uCT also confirmed a marked mineralization improvement. Finally, the growth plate and cortical bone of hyp femurs contained a massive accumulation of osteoblast-derived ASARM peptide(s) that was reduced in hyp animals treated with CA074 or pepstatin. This study confirms in vivo administration of cathepsin inhibitors improves bone mineralization in hyp mice. This may be due to a protease inhibitor mediated decrease in proteolytic degradation of the extracellular matrix and a reduced release of ASARM peptides (potent mineralization inhibitors). PMID:16762607

Intravenous nitroglycerin for controlled cord traction in the management of retained placenta.

PubMed

Visalyaputra, Shusee; Prechapanich, Japarath; Suwanvichai, Sukanya; Yimyam, Suwimol; Permpolprasert, Ladda; Suksopee, Pattipa

2011-02-01

To determine the effect of 200 μg of intravenous nitroglycerin in the release of retained placenta by controlled cord traction. In this randomized controlled study, 40 women with a placenta retained for 30 minutes received intravenously 200 μg of nitroglycerin or a normal saline solution before umbilical cord traction was initiated. The rates of successful removal of the retained placenta in the study (n=20) and control (n=20) groups were compared, as were blood pressure, pulse rate, blood loss, and adverse effects. The placenta was released in only 15% and 20% of the participants in the study and control group, respectively. The remainder of the participants required general anesthesia and manual removal of the retained placenta regardless of group assignation. Blood pressure fell in significantly more women in the study group, but there were no differences in estimated blood loss or minor adverse effects. Intravenously administered nitroglycerin did not facilitate the release of retained placenta by umbilical cord traction. However, cord traction may be performed longer than 30 minutes to attempt releasing the placenta before operative manual removal is initiated. Copyright © 2010 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

Non-random dispersal in the butterfly Maniola jurtina: implications for metapopulation models.

PubMed Central

Conradt, L; Bodsworth, E J; Roper, T J; Thomas, C D

2000-01-01

The dispersal patterns of animals are important in metapopulation ecology because they affect the dynamics and survival of populations. Theoretical models assume random dispersal but little is known in practice about the dispersal behaviour of individual animals or the strategy by which dispersers locate distant habitat patches. In the present study, we released individual meadow brown butterflies (Maniola jurtina) in a non-habitat and investigated their ability to return to a suitable habitat. The results provided three reasons for supposing that meadow brown butterflies do not seek habitat by means of random flight. First, when released within the range of their normal dispersal distances, the butterflies orientated towards suitable habitat at a higher rate than expected at random. Second, when released at larger distances from their habitat, they used a non-random, systematic, search strategy in which they flew in loops around the release point and returned periodically to it. Third, butterflies returned to a familiar habitat patch rather than a non-familiar one when given a choice. If dispersers actively orientate towards or search systematically for distant habitat, this may be problematic for existing metapopulation models, including models of the evolution of dispersal rates in metapopulations. PMID:11007325

Lactose digestion by human jejunal biopsies: the relationship between hydrolysis and absorption.

PubMed Central

Dawson, D J; Lobley, R W; Burrows, P C; Miller, V; Holmes, R

1986-01-01

The relationship between lactose hydrolysis and absorption of released glucose was investigated by determining the kinetics of lactose digestion by jejunal biopsies incubated in vitro. Lactase activity in intact biopsies correlated with conventional assay of tissue homogenates (r = 0.85, p less than 0.001), and glucose uptake from 28 mM lactose was directly proportional to lactase activity (r = 0.95, p less than 0.001) in 21 subjects with normal lactase levels, six with hypolactasia (primary or secondary to coeliac disease) and two with lactose intolerance but normal lactase activity. Kinetic analysis at 0.56-56 mM lactose in five normal subjects showed saturable kinetics for hydrolysis (app Km = 33.9 +/- 2.2 mM; app Vmax = 26.5 +/- 1.1 nmol/min/mg dry weight) but glucose uptake could be fitted to a model either of saturable uptake (app Kt = 47.2 +/- 0.3 mM; app Jmax = 14.1 +/- 0.2 nmol/min/mg) or saturable uptake plus a linear component (app Kt = 21.3 +/- 1.15; app Jmax = 4.59 +/- 0.12; app Kd = 0.093 +/- 0.010 nmol/min/mg/mM). The proportion of glucose taken into the tissue did not significantly exceed 50% of the total released at any lactose concentration suggesting the lack of an efficient capture mechanism for the released glucose. The results suggest that lactose hydrolysis is the rate limiting step in the overall absorption of glucose from lactose in vitro, and that the relationship between hydrolysis and absorption is the same in normal subjects and in hypolactasic subjects. PMID:3084346

Lack of effect of pancreatic polypeptide in the rate of gastric emptying and gut hormone release during breakfast.

PubMed

Adrian, T E; Greenberg, G R; Fitzpatrick, M L; Bloom, S R

1981-01-01

Bovine pancreatic polypeptide (PP) was infused intravenously in 5 healthy subjects on two separate occasions with mean doses of 1 and 2 pmol kg-1 min-1, respectively, which achieved plasma levels equal to and twice those observed after a normal mixed breakfast. The gastric emptying rate of a carbohydrate-rich breakfast 20 min after the start of each PP infusion was not significantly different from a control infusion of 0.15 M saline. PP is unlikely to be an important physiological modulator of gastric emptying rate in man.

Kinetics of dissolution of thorium and uranium doped britholite ceramics

NASA Astrophysics Data System (ADS)

Dacheux, N.; Du Fou de Kerdaniel, E.; Clavier, N.; Podor, R.; Aupiais, J.; Szenknect, S.

2010-09-01

In the field of immobilization of actinides in phosphate-based ceramics, several thorium and uranium doped britholite samples were submitted to leaching tests. The normalized dissolution rates determined for several pH values, temperatures and acidic media from the calcium release range from 4.7 × 10 -2 g m -2 d -1 to 21.6 g m -2 d -1. Their comparison with that determined for phosphorus, thorium and uranium revealed that the dissolution is clearly incongruent for all the conditions examined. Whatever the leaching solution considered, calcium and phosphorus elements were always released with higher RL values than the other elements (Nd, Th, U). Simultaneously, thorium was found to quickly precipitate as alteration product, leading to diffusion phenomena for uranium. For all the media considered, the uranium release is higher than that of thorium, probably due to its oxidation from tetravalent oxidation state to uranyl. Moreover, the evaluation of the partial order related to proton concentration and the apparent energy of activation suggest that the reaction of dissolution is probably controlled by surface chemical reactions occurring at the solid/liquid interface. Finally, comparative leaching tests performed in sulphuric acid solutions revealed a significant influence of such media on the chemical durability of the leached pellets, leading to higher normalized dissolution rates for all the elements considered. On the basis of the results of chemical speciation, this difference was mainly explained in the light of higher complexion constants by sulfate ions compared to nitrate, chloride and phosphate.

Liver glycogen in type 2 diabetic mice is randomly branched as enlarged aggregates with blunted glucose release.

PubMed

Besford, Quinn Alexander; Zeng, Xiao-Yi; Ye, Ji-Ming; Gray-Weale, Angus

2016-02-01

Glycogen is a vital highly branched polymer of glucose that is essential for blood glucose homeostasis. In this article, the structure of liver glycogen from mice is investigated with respect to size distributions, degradation kinetics, and branching structure, complemented by a comparison of normal and diabetic liver glycogen. This is done to screen for differences that may result from disease. Glycogen α-particle (diameter ∼ 150 nm) and β-particle (diameter ∼ 25 nm) size distributions are reported, along with in vitro γ-amylase degradation experiments, and a small angle X-ray scattering analysis of mouse β-particles. Type 2 diabetic liver glycogen upon extraction was found to be present as large loosely bound, aggregates, not present in normal livers. Liver glycogen was found to aggregate in vitro over a period of 20 h, and particle size is shown to be related to rate of glucose release, allowing a structure-function relationship to be inferred for the tissue specific distribution of particle types. Application of branching theories to small angle X-ray scattering data for mouse β-particles revealed these particles to be randomly branched polymers, not fractal polymers. Together, this article shows that type 2 diabetic liver glycogen is present as large aggregates in mice, which may contribute to the inflexibility of interconversion between glucose and glycogen in type 2 diabetes, and further that glycogen particles are randomly branched with a size that is related to the rate of glucose release.

Mechanisms of iodine release from iodoapatite in aqueous solution

NASA Astrophysics Data System (ADS)

Zhang, Z.; Wang, J.

2017-12-01

Immobilization of iodine-129 with waste forms in geological setting is challenging due to its extremely long half-life and high volatility in the environment. To evaluate the long-term performance of waste form, it is imperative to determine the release mechanism of iodine hosted in the waste form materials. This study investigated the iodine released from apatite structured waste form Pb9.85 (VO4)6 I1.7 to understand how diffusion and dissolution control the durability of apatite waste form. A standard semi-dynamic leach test was adopted in this study. Samples were exposed in fresh leachant periodically and the leachant was replaced after each interval. Each experiment was carried out in cap-sealed Teflon vessels under constant temperature (e.g. 90 °C). ICP-MS analysis on the reacted leachates shows that Pb and V were released constantly and congruently with the stoichiometric ratio of Pb/V. However, iodine release is incongruent and time dependent. The iodine release rate starts significantly higher than the corresponding stoichiometric value and gradually decreases, approaching the stoichiometric value. Therefore, a dual-mode mechanism is proposed to account for the iodine release from apatite, which is dominated by short-term diffusion and long-term dissolution processes. Additional tests show that the element release rates depend on a number of test parameters, including sample surface to solution volume ratio (m-1), interval (day), temperature (°C), and solution pH. This study provides a quantitative characterization of iodine release mechanism. The activation energy of iodine leaching 21±1.6 kJ/mol was obtained by varying the test temperature. At the test conditions of to neutral pH and 90 °C, the long-term iodine release rate 3.3 mg/(m2 • day) is projected by normalizing sample surface area to solution volume ratio (S/V) to 1.0 m-1 and interval to 1 day. These findings demonstrate i) the feasibility of our approach to quantify the release mechanism and ii) the performance of iodine apatite as a favorable waste form candidate for I-129 disposal.

Membrane properties involved in calcium-stimulated microparticle release from the plasma membranes of S49 lymphoma cells.

PubMed

Campbell, Lauryl E; Nelson, Jennifer; Gibbons, Elizabeth; Judd, Allan M; Bell, John D

2014-01-01

This study answered the question of whether biophysical mechanisms for microparticle shedding discovered in platelets and erythrocytes also apply to nucleated cells: cytoskeletal disruption, potassium efflux, transbilayer phospholipid migration, and membrane disordering. The calcium ionophore, ionomycin, disrupted the actin cytoskeleton of S49 lymphoma cells and produced rapid release of microparticles. This release was significantly inhibited by interventions that impaired calcium-activated potassium current. Microparticle release was also greatly reduced in a lymphocyte cell line deficient in the expression of scramblase, the enzyme responsible for calcium-stimulated dismantling of the normal phospholipid transbilayer asymmetry. Rescue of the scrambling function at high ionophore concentration also resulted in enhanced particle shedding. The effect of membrane physical properties was addressed by varying the experimental temperature (32-42°C). A significant positive trend in the rate of microparticle release as a function of temperature was observed. Fluorescence experiments with trimethylammonium diphenylhexatriene and Patman revealed significant decrease in the level of apparent membrane order along that temperature range. These results demonstrated that biophysical mechanisms involved in microparticle release from platelets and erythrocytes apply also to lymphocytes.

Characterization of 24-h cortisol release in obese and non-obese hyperandrogenic women.

PubMed

Miller, J E; Bray, M A; Faiman, C; Reyes, F I

1994-12-01

Excessive androgen output is a well-recognized feature of adrenocortical oversecretion in women with ovarian hyperandrogenism, or polycystic ovary disease (PCOD). However, evidence of a concomitant alteration of cortisol secretion is lacking even though obesity per se, a common clinical feature of PCOD, has been shown to be associated with cortisol oversecretion. To clarify whether a subtle alteration in cortisol secretion exists, a study of 24-h episodic cortisol release and post-prandial cortisol responses was undertaken in eight women with PCOD and eight normal women comprising equal numbers of obese and non-obese subjects. All four groups showed normal biphasic 24-h cortisol secretion profiles but cortisol pulse frequency was increased in the PCOD groups. Independently, both hyperandrogenism and obesity were associated with an accelerated cortisol clearance rate. These changes, together with normal or only slightly elevated 24-h cortisol integrated area under the curve, suggest an increased compensatory cortisol production in women with PCOD. Furthermore, subjects with PCOD and subjects with obesity showed different post-prandial cortisol responses to normal non-obese women. In conclusion, these subtle cortisol abnormalities may be a manifestation of altered central regulation of the hypothalamic-pituitary-adrenal axis and peripheral metabolic abnormalities, and may be linked to the pathophysiology of PCOD.

Chemical weathering in a tropical watershed, Luquillo Mountains, Puerto Rico: II. Rate and mechanism of biotite weathering

USGS Publications Warehouse

Murphy, S.F.; Brantley, S.L.; Blum, A.E.; White, A.F.; Dong, H.

1998-01-01

Samples of soil, saprolite, bedrock, and porewater from a lower montane wet forest, the Luquillo Experimental Forest (LEF) in Puerto Rico, were studied to investigate the rates and mechanisms of biotite weathering. The soil profile, at the top of a ridge in the Rio Icacos watershed, consists of a 50-100-cm thick layer of unstructured soil above a 600-800 cm thick saprolite developed on quartz diorite. The only minerals present in significant concentration within the soil and saprolite are biotite, quartz, kaolinite, and iron oxides. Biotite is the only primary silicate releasing significant K and Mg to porewaters. Although biotite in samples of the quartz diorite bedrock is extensively chloritized, chlorite is almost entirely absent in the saprolite phyllosilicates. Phyllosilicate grains are present as 200-1000 ??m wide books below about 50 cm depth. X-ray diffraction (XRD) and electron microprobe analyses indicate that the phyllosilicate grains contain a core of biotite surrounded by variable amounts of kaolinite. Lattice fringe images under transmission electron microscope (TEM) show single layers of biotite altering to two layers of kaolinite, suggesting dissolution of biotite and precipitation of kaolinite at discrete boundaries. Some single 14-A?? layers are also observed in the biotite under TEM. The degree of kaolinitization of individual phyllosilicate grains as observed by TEM decreases with depth in the saprolite. This TEM work is the first such microstructural evidence of epitaxial growth of kaolinite onto biotite during alteration in low-temperature environments. The rate of release of Mg in the profile, calculated as a flux through the soil normalized per watershed land area, is approximately 500 mol hectare-1 yr-1 (1.6 ?? 10-9 molMg m-2soil s-1). This rate is similar to the flux estimated from Mg discharge out the Rio Icacos (1000 mol hectare-1 yr-1, or 3.5 ?? 10-9 molMg m-2soil s-1), indicating that scaling up from the soil to the watershed is possible for Mg release. The rate of Mg release from biotite, normalized to Brunauer-Emmett-Teller (BET) surface area, is calculated using a mass balance equation which includes the density and volume of phyllosilicate grains, porewater chemistry and flux, and soil porosity. The mean rates of biotite weathering calculated from K and Mg release rates are approximately 6 and 11 ?? 10-16 molbiotite m-2biotite s-1 respectively, significantly slower than laboratory rates (10-12 to 10-11 molbiotite m-2biotite s-1). The discrepancy in scaling down from the soil to the laboratory is probably explained by (1) differences in weathering mechanism between the two environments, (2) higher solute concentrations in soil porewaters, (3) loss of reactive surface area of biotite in the saprolite due to kaolinite and iron oxide coatings, and/or (4) unaccounted-for heterogeneities in flow path through the soil. Copyright ?? 1998 Elsevier Science Ltd.

Estimating foundation water vapor release using a simple moisture balance and AIM-2 : case study of a contemporary wood-frame house

Treesearch

C. R. Boardman; Samuel V. Glass; Charles G. Carll

2010-01-01

Proper management of indoor humidity in buildings is an essential aspect of durability. Following dissipation of moisture from construction materials, humidity levels during normal operation are generally assumed to primarily depend on the building volume, the number of building occupants and their behavior, the air exchange rate, and the water vapor content of outdoor...

Quantitative Measurements of CH* Concentration in Normal Gravity and Microgravity Coflow Laminar Diffusion Flames

NASA Technical Reports Server (NTRS)

Giassi, D.; Cao, S.; Stocker, D. P.; Takahashi, F.; Bennett, B. A.; Smooke, M. D.; Long, M. B.

2015-01-01

With the conclusion of the SLICE campaign aboard the ISS in 2012, a large amount of data was made available for the analysis of the effect of microgravity on laminar coflow diffusion flames. Previous work focused on the study of sooty flames in microgravity as well as the ability of numerical models to predict its formation in a simplified buoyancy-free environment. The current work shifts the investigation to soot-free flames, putting an emphasis on the chemiluminescence emission from electronically excited CH (CH*). This radical species is of significant interest in combustion studies: it has been shown that the CH* spatial distribution is indicative of the flame front position and, given the relatively simple diagnostic involved with its measurement, several works have been done trying to understand the ability of CH* chemiluminescence to predict the total and local flame heat release rate. In this work, a subset of the SLICE nitrogen-diluted methane flames has been considered, and the effect of fuel and coflow velocity on CH* concentration is discussed and compared with both normal gravity results and numerical simulations. Experimentally, the spectral characterization of the DSLR color camera used to acquire the flame images allowed the signal collected by the blue channel to be considered representative of the CH* emission centered around 431 nm. Due to the axisymmetric flame structure, an Abel deconvolution of the line-of-sight chemiluminescence was used to obtain the radial intensity profile and, thanks to an absolute light intensity calibration, a quantification of the CH* concentration was possible. Results show that, in microgravity, the maximum flame CH* concentration increases with the coflow velocity, but it is weakly dependent on the fuel velocity; normal gravity flames, if not lifted, tend to follow the same trend, albeit with different peak concentrations. Comparisons with numerical simulations display reasonably good agreement between measured and computed flame lengths and radii, and it is shown that the integrated CH* emission scales proportionally to the computed total heat release rate; the two-dimensional CH* spatial distribution, however, does not appear to be a good marker for the local heat release rate.

The dispersion releaser technology is an effective method for testing drug release from nanosized drug carriers.

PubMed

Janas, Christine; Mast, Marc-Phillip; Kirsamer, Li; Angioni, Carlo; Gao, Fiona; Mäntele, Werner; Dressman, Jennifer; Wacker, Matthias G

2017-06-01

The dispersion releaser (DR) is a dialysis-based setup for the analysis of the drug release from nanosized drug carriers. It is mounted into dissolution apparatus2 of the United States Pharmacopoeia. The present study evaluated the DR technique investigating the drug release of the model compound flurbiprofen from drug solution and from nanoformulations composed of the drug and the polymer materials poly (lactic acid), poly (lactic-co-glycolic acid) or Eudragit®RSPO. The drug loaded nanocarriers ranged in size between 185.9 and 273.6nm and were characterized by a monomodal size distribution (PDI<0.1). The membrane permeability constants of flurbiprofen were calculated and mathematical modeling was applied to obtain the normalized drug release profiles. For comparing the sensitivities of the DR and the dialysis bag technique, the differences in the membrane permeation rates were calculated. Finally, different formulation designs of flurbiprofen were sensitively discriminated using the DR technology. The mechanism of drug release from the nanosized carriers was analyzed by applying two mathematical models described previously, the reciprocal powered time model and the three parameter model. Copyright © 2017 Elsevier B.V. All rights reserved.

Characterization of crack growth under combined loading

NASA Technical Reports Server (NTRS)

Feldman, A.; Smith, F. W.; Holston, A., Jr.

1977-01-01

Room-temperature static and cyclic tests were made on 21 aluminum plates in the shape of a 91.4x91.4-cm Maltese cross with 45 deg flaws to develop crack growth and fracture toughness data under mixed-mode conditions. During cyclic testing, it was impossible to maintain a high proportion of shear-mode deformation on the crack tips. Cracks either branched or turned. Under static loading, cracks remained straight if shear stress intensity exceeded normal stress intensity. Mixed-mode crack growth rate data compared reasonably well with published single-mode data, and measured crack displacements agreed with the straight and branched crack analyses. Values of critical strain energy release rate at fracture for pure shear were approximately 50% higher than for pure normal opening, and there was a large reduction in normal stress intensity at fracture in the presence of high shear stress intensity. Net section stresses were well into the inelastic range when fracture occurred under high shear on the cracks.

Increased Urinary Adenosine Triphosphate in Patients With Bladder Outlet Obstruction Due to Benign Prostate Hyperplasia.

PubMed

Silva-Ramos, Miguel; Silva, Isabel; Oliveira, José Carlos; Correia-de-Sá, Paulo

2016-11-01

Diagnosis of bladder outflow obstruction (BOO) in patients with lower urinary tract (LUT) symptoms is challenging without using invasive urodynamic tests. Recently, we showed in vitro that urothelial strips from patients with benign prostatic hyperplasia (BPH) release more ATP than controls. Here, we tested whether urinary ATP can be used as a wall tension transducer non-invasive biomarker to detect BOO in patients with BPH. 79 male patients with BOO and 22 asymptomatic controls were recruited prospectively. Patients were asked to complete the International Prostate Symptom Score (IPSS) questionnaire and to void at normal desire into a urinary flowmeter; the postvoid residual volume was determined by suprapubic ultrasonography. Urine samples from all individuals were examined for ATP, creatinine, and lactate dehydrogenase. BOO patients had significantly higher (P < 0.001) urinary ATP normalized by the voided volume (456 ± 36 nmol) than age-matched controls (209 ± 35 nmol). Urinary ATP amounts increased with the voided volume, but the slope of this rise was higher in BOO patients than in controls. A negative correlation was detected between urinary ATP and flow rate parameters, namely maximal flow rate (r = -0.310, P = 0.005), Siroky flow-volume normalization (r = -0.324, P = 0.004), and volume-normalized flow rate index (r = -0.320, P = 0.012). We found no correlation with LUT symptoms IPSS score. Areas under the receiver operator characteristics (ROC) curves were 0.91 (95%CI 0.86-0.96, P < 0.001) for ATP alone and 0.88 (95%CI 0.81-0.94, P < 0,001) when adjusted to urinary creatinine. Patients with BOO release higher amounts of ATP into the urine than the control group. The high area under the ROC curve suggests that urinary ATP can be a high-sensitive non-invasive biomarker of BOO, which may have a discriminative value of detrusor competence when comparing BPH patients with low urinary flow rates. Prostate 76:1353-1363, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Effect of administration of corticotropin-releasing hormone and glucocorticoid on arginine vasopressin response to osmotic stimulus in normal subjects and patients with hypocorticotropinism without overt diabetes insipidus.

PubMed

Yamada, K; Tamura, Y; Yoshida, S

1989-08-01

We examined the effect of CRH administration on the response of plasma arginine vasopressin (AVP) induced by an osmotic stimulus in six normal subjects and five patients with hypocorticotropinism without overt diabetes insipidus (four patients with Sheehan's syndrome and one with idiopathic pituitary dwarfism with ACTH deficiency). Hypertonic saline infusion (855 mmol/L saline solutions at a rate of 205 mumol/kg.min for 10 min) increased plasma AVP 5.7-fold (P less than 0.01) in normal subjects and 2.4-fold (P less than 0.05) in the patients. CRH administration significantly augmented the plasma AVP response to the osmotic stimulus in the normal subjects, but not in the patients with hypocorticotropinism. CRH administration alone did not influence plasma AVP. These findings suggest that a central CRH-related mechanism(s) was at least partly involved in the augmentation of AVP release. Based on the relatively low plasma AVP response to the osmotic stimulus in patients and their lower plasma AVP levels and higher plasma osmolality under basal conditions, we suggest that patients with hypocorticotropinism have partial diabetes insipidus, in which impairment of central CRH action might be, at least in part, involved. The response of plasma AVP to the osmotic stimulus was attenuated significantly when the patients were given cortisol. Since basal PRA, plasma aldosterone, plasma osmolality, hematocrit, body weight, mean blood pressure, and heart rate were similar with and without cortisol administration, this effect of cortisol may have been due to central suppression of the AVP response to the osmotic stimulus.

Characterization of wear debris from metal-on-metal hip implants during normal wear versus edge-loading conditions.

PubMed

Kovochich, Michael; Fung, Ernest S; Donovan, Ellen; Unice, Kenneth M; Paustenbach, Dennis J; Finley, Brent L

2018-04-01

Advantages of second-generation metal-on-metal (MoM) hip implants include low volumetric wear rates and the release of nanosized wear particles that are chemically inert and readily cleared from local tissue. In some patients, edge loading conditions occur, which result in higher volumetric wear. The objective of this study was to characterize the size, morphology, and chemistry of wear particles released from MoM hip implants during normal (40° angle) and edge-loading (65° angle with microseparation) conditions. The mean primary particle size by volume under normal wear was 35 nm (range: 9-152 nm) compared with 95 nm (range: 6-573 nm) under edge-loading conditions. Hydrodynamic diameter analysis by volume showed that particles from normal wear were in the nano- (<100 nm) to submicron (<1000 nm) size range, whereas edge-loading conditions generated particles that ranged from <100 nm up to 3000-6000 nm in size. Particles isolated from normal wear were primarily chromium (98.5%) and round to oval in shape. Edge-loading conditions generated more elongated particles (4.5%) (aspect ratio ≥ 2.5) and more CoCr alloy particles (9.3%) compared with normal wear conditions (1.3% CoCr particles). By total mass, edge-loading particles contained approximately 640-fold more cobalt than normal wear particles. Our findings suggest that high wear conditions are a potential risk factor for adverse local tissue effects in MoM patients who experience edge loading. This study is the first to characterize both the physical and chemical characteristics of MoM wear particles collected under normal and edge-loading conditions. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 986-996, 2018. © 2017 Wiley Periodicals, Inc.

Gonadotropin-releasing hormone for infertility in women with primary hypothalamic amenorrhea. Toward a more-interventional approach.

PubMed

Kesrouani, A; Abdallah, M A; Attieh, E; Abboud, J; Atallah, D; Makhoul, C

2001-01-01

To assess the effectiveness of a protocol of pulsatile gonadotropin releasing-hormone (GnRH) in treating infertility in women with primary hypothalamic amenorrhea. Retrospective analysis of 44 cycles treated at an infertility center. Twenty-four patients with primary hypothalamic amenorrhea were treated intravenously with pulsatile GnRH using 5 micrograms per bolus every 90 minutes. Ultrasound monitoring and cervical assessment by Insler's scoring system allowed timed injection of human chorionic gonadotropin (hCG) and intrauterine insemination if needed. Luteal support was provided with hCG. The ovulation rate was 95% with the 5-microgram dose. A single follicle was produced in 91% of cycles. The overall pregnancy rate per ovulatory cycle was 45%, and the pregnancy rate per patient was 83%. In patients treated previously with exogenous gonadotropins, poor results were observed. Only one case of mild overstimulation was reported. Pulsatile GnRH is an effective and safe method of treating infertility in women with primary hypothalamic amenorrhea, thus simulating normal ovulation; however, more-interventional management, including the qualitative estrogenic response, may lead to optimal results and increase the pregnancy rate.

Calcium channel blockers and transmitter release at the normal human neuromuscular junction.

PubMed

Protti, D A; Reisin, R; Mackinley, T A; Uchitel, O D

1996-05-01

Transmitter release evoked by nerve stimulation is highly dependent on Ca2+ entry through voltage-activated plasma membrane channels. Calcium influx may be modified in some neuromuscular diseases like Lambert-Eaton syndrome and amyotrophic lateral sclerosis. We studied the pharmacologic sensitivity of the transmitter release process to different calcium channel blockers in normal human muscles and found that funnel web toxin and omega-Agatoxin-IVA, both P-type calcium channel blockers, blocked nerve-elicited muscle action potentials and inhibited evoked synaptic transmission. The transmitter release was not affected either by nitrendipine, an L-type channel blocker, or omega-Conotoxin-GVIA, an N-type channel blocker. The pharmacologic profile of neuromuscular transmission observed in normal human muscles indicates that P-like channels mediate transmitter release at the motor nerve terminals.

Mechanism of ipamorelin-evoked insulin release from the pancreas of normal and diabetic rats.

PubMed

Adeghate, Ernest; Ponery, Abdul Samad

2004-12-01

To examine the effect of ipamorelin (IPA), a novel pentapeptide with a strong growth hormone releasing potency, on insulin secretion from pancreatic tissue fragments of normal and diabetic rats. Diabetes mellitus was induced by streptozotocin (60 mg kg(-1)). Four weeks after the induction of diabetes, pancreatic tissue fragments of normal and diabetic rats were removed and incubated with different concentrations (10(-12) - 10(-6) M) of IPA. Insulin release from the pancreas was measured by radioimmunoassay. Ipamorelin evoked significant (p<0.04) increases in insulin secretion from the pancreas of normal and diabetic rats. Either diltiazem or yohimbine or propranolol or a combination of atropine, propranolol and yohimbine inhibited IPA-evoked insulin secretion significantly (p<0.03) from the pancreas of normal and diabetic rats. Atropine caused a significant (p<0.007) reduction in the IPA-induced insulin secretion in diabetic but not in normal rats. IPA stimulates insulin release through the calcium channel and the adrenergic receptor pathways. This is the first study to examine the effect of ipamorelin on insulin secretion in the pancreas.

Dual turn-on fluorescence signal-based controlled release system for real-time monitoring of drug release dynamics in living cells and tumor tissues.

PubMed

Kong, Xiuqi; Dong, Baoli; Song, Xuezhen; Wang, Chao; Zhang, Nan; Lin, Weiying

2018-01-01

Controlled release systems with capabilities for direct and real-time monitoring of the release and dynamics of drugs in living systems are of great value for cancer chemotherapy. Herein, we describe a novel dual turn-on fluorescence signal-based controlled release system ( CDox ), in which the chemotherapy drug doxorubicin ( Dox ) and the fluorescent dye ( CH ) are conjugated by a hydrazone moiety, a pH-responsive cleavable linker. CDox itself shows nearly no fluorescence as the fluorescence of CH and Dox is essentially quenched by the C=N isomerization and N-N free rotation. However, when activated under acidic conditions, CDox could be hydrolyzed to afford Dox and CH , resulting in dual turn-on signals with emission peaks at 595 nm and 488 nm, respectively. Notably, CDox exhibits a desirable controlled release feature as the hydrolysis rate is limited by the steric hindrance effect from both the Dox and CH moieties. Cytotoxicity assays indicate that CDox shows much lower cytotoxicity relative to Dox , and displays higher cell inhibition rate to cancer than normal cells. With the aid of the dual turn-on fluorescence at different wavelengths, the drug release dynamics of CDox in living HepG2 and 4T-1 cells was monitored in double channels in a real-time fashion. Importantly, two-photon fluorescence imaging of CDox in living tumor tissues was also successfully performed by high-definition 3D imaging. We expect that the unique controlled release system illustrated herein could provide a powerful means to investigate modes of action of drugs, which is critical for development of much more robust and effective chemotherapy drugs.

Model of reticuloendothelial iron metabolism in humans: Abnormal behavior in idiopathic hemochromatosis and in inflammation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fillet, G.; Beguin, Y.; Baldelli, L.

1989-08-01

Iron transport in the reticuloendothelial (RE) system plays a central role in iron metabolism, but its regulation has not been characterized physiologically in vivo in humans. In particular, why serum iron is elevated and RE cells are much less iron-loaded than parenchymal cells in idiopathic hemochromatosis is not known. The processing of erythrocyte iron by the RE system was studied after intravenous (IV) injection of 59Fe heat-damaged RBCs (HDRBCs) and 55Fe transferrin in normal subjects and in patients with iron deficiency, idiopathic hemochromatosis, inflammation, marrow aplasia, or hyperplastic erythropoiesis. Early release of 59Fe by the RE system was calculated frommore » the plasma iron turnover and the 59Fe plasma reappearance curve. Late release was calculated from the ratio of 59Fe/55Fe RBC utilization in 2 weeks. The partitioning of iron between the early (release from heme catabolism) and late (release from RE stores) phases depended on the size of RE iron stores, as illustrated by the inverse relationship observed between early release and plasma ferritin (P less than .001). There was a strong correlation between early release and the rate of change of serum iron levels during the first three hours in normal subjects (r = .85, P less than .001). Inflammation produced a blockade of the early release phase, whereas in idiopathic hemochromatosis early release was considerably increased as compared with subjects with similar iron stores. Based on these results, we describe a model of RE iron metabolism in humans. We conclude that the RE system appears to determine the diurnal fluctuations in serum iron levels through variations in the immediate output of heme iron. In idiopathic hemochromatosis, a defect of the RE cell in withholding iron freed from hemoglobin could be responsible for the high serum iron levels and low RE iron stores.« less

Cell-derived microparticles after exercise in individuals with G6PD Viangchan.

PubMed

Chanda, Makamas; Nantakomol, Duangdao; Suksom, Daroonwan; Palasuwan, Attakorn

2015-07-16

Glucose-6-phospate dehydrogenase (G6PD) deficient cells are sensitive to oxidative damage leading to the formation of microparticles (MPs). Therefore, we examined the concentration of MPs and changes in the antioxidant balance after an acute strenuous exercise (SEx) and moderate-intensity exercise (MEx). Eighteen healthy females (18-24 years) with G6PD normal and eighteen age-matched females with G6PD Viangchan (871G>A) were tested by running on a treadmill at their maximal oxygen uptake for SEx and at 75% of their maximal heart rate for MEx. It was found that SEx triggered the release of total microparticles (TTMPs) above baseline levels and remained significantly higher 45 minutes after the exercise in G6PD normal individuals. However, SEx-induced increase in TTMPs was significantly higher in G6PD Viangchan as compared to G6PD normal. In contrast, MEx did not to alter the release of TTMPs in both G6PD normal and Viangchan. Moreover, TTMPs concentrations were inversely correlated with G6PD activity (r =-0.82, P <  0.05) but positively correlated with MDA concentrations (r = 0.74, P <  0.05). Using cell specific antibodies, we determined that MPs were mainly derived from platelets and erythrocytes. Altogether, the present study indicates that G6PD Viangchan may participate in MEx without higher MPs concentration and oxidative stress compared with G6PD normal.

Strain energy release rate analysis of delamination in a tapered laminate subjected to tension load

NASA Technical Reports Server (NTRS)

Salpekar, S. A.; Raju, I. S.; Obrien, T. K.

1990-01-01

A tapered composite laminate subjected to tension load was analyzed using the finite-element method. The glass/epoxy laminate has a (+ or - 45)sub 3 group of plies dropped in three distinct steps, each 20 ply-thicknesses apart, thus forming a taper angle of 5.71 degrees. Steep gradients of interlaminar normal and shear stress on a potential delamination interface suggest the existence of stress singularities at the points of material and geometric discontinuities created by the internal plydrops. The delamination was assumed to initiate at the thin end of the taper on a -45/+45 interface and the delamination growth was simulated in both directions, i.e., along the taper and into the thin region. The strain-energy-release rate for a delamination growing into the thin laminate consisted predominantly of mode I (opening) component. For a delamination growing along the tapered region, the strain-energy-release rate was initially all mode I, but the proportion of mode I decreased with increase in delamination size until eventually total G was all mode II. The total G for both delamination tips increased with increase in delamination size, indicating that a delamination initiating at the end of the taper will grow unstably along the taper and into the thin laminate simultaneously.

Biphasic insulin-releasing effect of BTS 67 582 in rats.

PubMed

Storey, D A; Bailey, C J

1998-12-01

BTS 67 582 (1,1-dimethyl-2(2-morpholinophenyl)guanidine fumarate) is being developed as a short-acting anti-diabetic insulin secretagogue. The effect of BTS 67 582 on the phasic pattern of insulin release was assessed in anaesthetized normal rats by measuring arterial plasma insulin concentrations while arterial glucose concentrations were fixed at 6, 8.5 and 12.5 mM. Intravenous BTS 67 582 (10 mg kg(-1)) induced an immediate but transient increase in insulin concentrations which declined by 10 min (first phase). This was followed by a smaller but sustained increase in insulin concentrations (second phase). The increment from basal to peak insulin release (0-2 min) was independent of glucose, but the first phase was maintained for longer and the second phase was greater at the highest concentration of glucose (12.5 mM). BTS 67 582 also extended the first-phase insulin response to a standard intravenous glucose challenge and enhanced the rate of glucose disappearance by approximately 12%. Thus BTS 67 582 causes biphasic stimulation of insulin release and augments the insulin-releasing effect of glucose.

On factors controlling precursor slip fronts in the laboratory and their relation to slow slip events in nature

NASA Astrophysics Data System (ADS)

Selvadurai, Paul A.; Glaser, Steven D.; Parker, Jessica M.

2017-03-01

Spatial variations in frictional properties on natural faults are believed to be a factor influencing the presence of slow slip events (SSEs). This effect was tested on a laboratory frictional interface between two polymethyl methacrylate (PMMA) bodies. We studied the evolution of slip and slip rates that varied systematically based on the application of both high and low normal stress (σ0=0.8 or 0.4 MPa) and the far-field loading rate (VLP). A spontaneous, frictional rupture expanded from the central, weaker, and more compliant section of the fault that had fewer asperities. Slow rupture propagated at speeds Vslow˜0.8 to 26 mm s-1 with slip rates from 0.01 to 0.2 μm s-1, resulting in stress drops around 100 kPa. During certain nucleation sequences, the fault experienced a partial stress drop, referred to as precursor detachment fronts in tribology. Only at the higher level of normal stress did these fronts exist, and the slip and slip rates mimicked the moment and moment release rates during the 2013-2014 Boso SSE in Japan. The laboratory detachment fronts showed rupture propagation speeds Vslow/VR∈ (5 to 172) × 10-7 and stress drops ˜ 100 kPa, which both scaled to the aforementioned SSE. Distributions of asperities, measured using a pressure sensitive film, increased in complexity with additional normal stress—an increase in normal stress caused added complexity by increasing both the mean size and standard deviation of asperity distributions, and this appeared to control the presence of the detachment front.

Corticotropin-releasing hormone and pituitary-adrenal hormones in pregnancies complicated by chronic hypertension.

PubMed

Warren, W B; Gurewitsch, E D; Goland, R S

1995-02-01

We hypothesized that maternal plasma corticotropin-releasing hormone levels are elevated in chronic hypertension and that elevations modulate maternal and fetal pituitary-adrenal function. Venous blood samples and 24-hour urine specimens were obtained in normal and hypertensive pregnancies at 21 to 40 weeks of gestation. Corticotropin-releasing hormone, corticotropin, cortisol, dehydroepiandrosterone sulfate, and total estriol levels were measured by radioimmunoassay. Mean hormone levels were compared by unpaired t test or two-way analysis of variance. Plasma corticotropin-releasing hormone levels were elevated early in hypertensive pregnancies but did not increase after 36 weeks. Levels of pituitary and adrenal hormones were not different in normal and hypertensive women. However, maternal plasma estriol levels were lower in hypertensive pregnancies compared with normal pregnancies. Fetal 16-hydroxy dehydroepiandrosterone sulfate, the major precursor to placental estriol production, has been reported to be lower than normal in hypertensive pregnancies, possibly explaining the decreased plasma estriol levels reported here. Early stimulation of placental corticotropin-releasing hormone production or secretion may be related to accelerated maturation of placental endocrine function in pregnancies complicated by chronic hypertension.

ATP release from bladder urothelium and serosa in a rat model of partial bladder outlet obstruction.

PubMed

Shiina, Kazuhiro; Hayashida, Ken-Ichiro; Ishikawa, Kazuo; Kawatani, Masahito

2016-01-01

Overactive bladder is one of the major health problem especially in elderly people. Adenosine triphosphate (ATP) is released from urinary bladder cells and acts as a smooth muscle contraction and sensory signal in micturition but little is known about the role of ATP release in the pathophysiology of overactive bladder. To assess the relationship between ATP and overactive bladder, we used a partial bladder outlet obstruction (pBOO) model in rats. The bladder caused several changes by pBOO: An increase in bladder weight, hypertrophy of sub-urothelium and sub-serosal area, and frequent non-voiding bladder contraction during urine storage. Basal ATP release from urothelium and serosa of pBOO rats was significantly higher than that of normal rats. Distentioninduced ATP release from urothelium of normal and pBOO rats had no significant change. However, distention-induced ATP release from serosa of pBOO rats was higher than that of normal. These findings may identify ATP especially released from serosa as one of causes of non-voiding contractions and overactive bladder symptoms.

Pac-man motility of kinetochores unleashed by laser microsurgery

PubMed Central

LaFountain, James R.; Cohan, Christopher S.; Oldenbourg, Rudolf

2012-01-01

We report on experiments directly in living cells that reveal the regulation of kinetochore function by tension. X and Y sex chromosomes in crane fly (Nephrotoma suturalis) spermatocytes exhibit an atypical segregation mechanism in which each univalent maintains K-fibers to both poles. During anaphase, each maintains a leading fiber (which shortens) to one pole and a trailing fiber (which elongates) to the other. We used this intriguing behavior to study the motile states that X-Y kinetochores are able to support during anaphase. We used a laser microbeam to either sever a univalent along the plane of sister chromatid cohesion or knock out one of a univalent's two kinetochores to release one or both from the resistive influence of its sister's K-fiber. Released kinetochores with attached chromosome arms moved poleward at rates at least two times faster than normal. Furthermore, fluorescent speckle microscopy revealed that detached kinetochores converted their functional state from reverse pac-man to pac-man motility as a consequence of their release from mechanical tension. We conclude that kinetochores can exhibit pac-man motility, even though their normal behavior is dominated by traction fiber mechanics. Unleashing of kinetochore motility through loss of resistive force is further evidence for the emerging model that kinetochores are subject to tension-sensitive regulation. PMID:22740625

Functionalized graphene oxide nanoparticles for cancer cell-specific delivery of antitumor drug.

PubMed

Zhao, Xubo; Yang, Liangwei; Li, Xiaorui; Jia, Xu; Liu, Lei; Zeng, Jin; Guo, Jinshan; Liu, Peng

2015-01-21

The unique reduction-triggered functional graphene oxide nanoparticles (GON) with well-defined size and uniform distribution were designed as an innovative drug delivery platform for cancer treatment for the first time, via the redox radical polymerization of methacrylic acid from the polyethylene glycol (PEG) modified GON (GON-PEG), following by cross-linking with cystamine. Thermogravimetric analysis demonstrates that the typical PMAA2-GON-PEG carriers contain about 16 wt % PEG segments and 33 wt % poly(methacrylic acid) (PMAA) brushes. PEG moieties are incorporated to make the drug delivery platforms stealthy during blood circulation. Notably, introducing the cross-linked PMAA brushes efficiently minimizes the premature release of doxorubicin (DOX) in the stimulated normal tissues, and accelerates DOX release in the stimulated tumor tissues through response to reduce agent. The carriers showed a 6-fold faster releasing rate at pH 5.0 in the presence of 10 mM glutathione (GSH) (stimulated tumor tissues) than at pH 7.4 with 10 μM GSH (stimulated normal tissues). In vitro cytotoxicity test also showed that the cross-linked PMAA2-GON-PEG (CPMAA2-GON-PEG) carriers had remarkable cytocompatibility, and that the DOX-loaded CPMAA2-GON-PEG had excellent killing capability to SiHa cells.

Self-assembled phytosterol-fructose-chitosan nanoparticles as a carrier of anticancer drug.

PubMed

Qiu, Yeyan; Zhu, Jun; Wang, Jianting; Gong, Renmin; Zheng, Mingming; Huang, Fenghong

2013-08-01

Self-assembled nanoparticles were synthesized from water-soluble fructose-chitosan, substituted by succinyl linkages with phytosterols as hydrophobic moieties for self-assembly. The physicochemical properties of the prepared self-assembled nanoparticles were characterized by Fourier transform infrared spectroscopy, fluorescence spectroscopy, and transmission electron microscopy. Doxorubicin (DOX), as a model anticancer drug, was physically entrapped inside prepared self-assembled nanoparticles by the dialysis method. With increasing initial levels of the drug, the drug loading content increased, but the encapsulation efficiency decreased. The release profiles in vitro demonstrated that the DOX showed slow sustained released over 48 h, and the release rate in phosphate buffered saline (PBS) solution (pH 7.4) was much slower than in PBS solution (pH 5.5 and pH 6.5), indicating the prepared self-assembled nanoparticles had the potential to be used as a carrier for targeted delivery of hydrophobic anticancer drugs with declined cytotoxicity to normal tissues.

Flame thickness and conditional scalar dissipation rate in a premixed temporal turbulent reacting jet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chaudhuri, Swetaprovo; Kolla, Hemanth; Dave, Himanshu L.

The flame structure corresponding to lean hydrogen–air premixed flames in intense sheared turbulence in the thin reaction zone regime is quantified from flame thickness and conditional scalar dissipation rate statistics, obtained from recent direct numerical simulation data of premixed temporally-evolving turbulent slot jet flames. It is found that, on average, these sheared turbulent flames are thinner than their corresponding planar laminar flames. Extensive analysis is performed to identify the reason for this counter-intuitive thinning effect. The factors controlling the flame thickness are analyzed through two different routes i.e., the kinematic route, and the transport and chemical kinetics route. The kinematicmore » route is examined by comparing the statistics of the normal strain rate due to fluid motion with the statistics of the normal strain rate due to varying flame displacement speed or self-propagation. It is found that while the fluid normal straining is positive and tends to separate iso-scalar surfaces, the dominating normal strain rate due to self-propagation is negative and tends to bring the iso-scalar surfaces closer resulting in overall thinning of the flame. The transport and chemical kinetics route is examined by studying the non-unity Lewis number effect on the premixed flames. The effects from the kinematic route are found to couple with the transport and chemical kinetics route. In addition, the intermittency of the conditional scalar dissipation rate is also examined. It is found to exhibit a unique non-monotonicity of the exponent of the stretched exponential function, conventionally used to describe probability density function tails of such variables. As a result, the non-monotonicity is attributed to the detailed chemical structure of hydrogen-air flames in which heat release occurs close to the unburnt reactants at near free-stream temperatures.« less

Flame thickness and conditional scalar dissipation rate in a premixed temporal turbulent reacting jet

DOE PAGES

Chaudhuri, Swetaprovo; Kolla, Hemanth; Dave, Himanshu L.; ...

2017-07-07

The flame structure corresponding to lean hydrogen–air premixed flames in intense sheared turbulence in the thin reaction zone regime is quantified from flame thickness and conditional scalar dissipation rate statistics, obtained from recent direct numerical simulation data of premixed temporally-evolving turbulent slot jet flames. It is found that, on average, these sheared turbulent flames are thinner than their corresponding planar laminar flames. Extensive analysis is performed to identify the reason for this counter-intuitive thinning effect. The factors controlling the flame thickness are analyzed through two different routes i.e., the kinematic route, and the transport and chemical kinetics route. The kinematicmore » route is examined by comparing the statistics of the normal strain rate due to fluid motion with the statistics of the normal strain rate due to varying flame displacement speed or self-propagation. It is found that while the fluid normal straining is positive and tends to separate iso-scalar surfaces, the dominating normal strain rate due to self-propagation is negative and tends to bring the iso-scalar surfaces closer resulting in overall thinning of the flame. The transport and chemical kinetics route is examined by studying the non-unity Lewis number effect on the premixed flames. The effects from the kinematic route are found to couple with the transport and chemical kinetics route. In addition, the intermittency of the conditional scalar dissipation rate is also examined. It is found to exhibit a unique non-monotonicity of the exponent of the stretched exponential function, conventionally used to describe probability density function tails of such variables. As a result, the non-monotonicity is attributed to the detailed chemical structure of hydrogen-air flames in which heat release occurs close to the unburnt reactants at near free-stream temperatures.« less

Bioreactor validation and biocompatibility of Ag/poly(N-vinyl-2-pyrrolidone) hydrogel nanocomposites.

PubMed

Jovanović, Zeljka; Radosavljević, Aleksandra; Kačarević-Popović, Zorica; Stojkovska, Jasmina; Perić-Grujić, Aleksandra; Ristić, Mirjana; Matić, Ivana Z; Juranić, Zorica D; Obradovic, Bojana; Mišković-Stanković, Vesna

2013-05-01

Silver/poly(N-vinyl-2-pyrrolidone) (Ag/PVP) nanocomposites containing Ag nanoparticles at different concentrations were synthesized using γ-irradiation. Cytotoxicity of the obtained nanocomposites was determined by MTT assay in monolayer cultures of normal human immunocompetent peripheral blood mononuclear cells (PBMC) that were either non-stimulated or stimulated to proliferate by mitogen phytohemagglutinin (PHA), as well as in human cervix adenocarcinoma cell (HeLa) cultures. Silver release kinetics and mechanical properties of nanocomposites were investigated under bioreactor conditions in the simulated body fluid (SBF) at 37°C. The release of silver was monitored under static conditions, and in two types of bioreactors: perfusion bioreactors and a bioreactor with dynamic compression coupled with SBF perfusion simulating in vivo conditions in articular cartilage. Ag/PVP nanocomposites exhibited slight cytotoxic effects against PBMC at the estimated concentration of 0.4 μmol dm(-3), with negligible variations observed amongst different cell cultures investigated. Studies of the silver release kinetics indicated internal diffusion as the rate limiting step, determined by statistically comparable results obtained at all investigated conditions. However, silver release rate was slightly higher in the bioreactor with dynamic compression coupled with SBF perfusion as compared to the other two systems indicating the influence of dynamic compression. Modelling of silver release kinetics revealed potentials for optimization of Ag/PVP nanocomposites for particular applications as wound dressings or soft tissue implants. Copyright © 2013 Elsevier B.V. All rights reserved.

Subduction and dehydration of slow-spread oceanic lithosphere

NASA Astrophysics Data System (ADS)

Paulatto, M.; Laigle, M.; Galve, A.; Charvis, P.

2016-12-01

Water transported by subducting slabs affects the dynamics of subduction zones and is a major gateway in the global geochemical water cycle. During subduction much of the water stored in the slab is released via pore fluid escape and through metamorphic reactions that depend on the thermal regime. The most notable are eclogitization of hydrated basalt and gabbro and breakdown of serpentinite. Most constraints to date have been obtained at Pacific subduction zones, and have contributed to a model of slab dehydration applicable to normal fast-spread oceanic lithosphere with a mafic crust. Slow-spread crust however, is heterogeneous in thickness and composition and has a different water distribution than fast-spread crust. We use P-wave traveltimes from several active source seismic experiments and P- and S-wave traveltimes from shallow and intermediate depth (< 160 km) local earthquakes recorded on a vast amphibious array of OBSs and land seismometers to recover the 3D Vp and Vp/Vs structure of the central Lesser Antilles subduction zone from the surface to 160 km depth. This slab was formed by slow accretion at the Mid-Atlantic ridge and represents the global slow accretion rate end-member. We image the dipping low-Vp layer at the top of the slab corresponding to the hydrated slab crust penetrating to about 100 km depth. High Vp/Vs ratio on the slab top and in the forearc crust is interpreted as evidence of elevated fluid content either as free fluids or as bound water in hydrated minerals. A local minimum in Vp is observed on the slab top at 50 km depth, and forms an elongated trench-parallel anomaly. This anomaly is interrupted at the projection of the Marathon fracture zone. We suggest that this is the result of lateral variations in slab crust composition from normal mafic oceanic crust to tectonized oceanic crust consisting to a large extent of serpentinized peridotite near the fracture zone. Slab regions with normal mafic oceanic crust likely undergo eclogitization, resulting in voluminous water release over a narrow depth range. Serpentinized ultramafic crust, in contrast, may release water at a more constant rate. We infer that subduction of slow-spread lithosphere may result in heterogeneous water transport and release at subduction zones with implications for seismicity, magma generation and the geochemical budget.

Protein Degradation in Normal and Beige (Chediak-Higashi) Mice

PubMed Central

Lyons, Robert T.; Pitot, Henry C.

1978-01-01

The beige mouse, C57BL/6 (bg/bg), is an animal model for the Chediak-Higashi syndrome in man, a disease characterized morphologically by giant lysosomes in most cell types. Half-lives for the turnover of [14C]bicarbonate-labeled total soluble liver protein were determined in normal and beige mice. No significant differences were observed between the normal and mutant strain for both rapidly and slowly turning-over classes of proteins. Glucagon treatment during the time-course of protein degradation had similar effects on both normal and mutant strains and led to the conclusion that the rate of turnover of endogenous intracellular protein in the beige mouse liver does not differ from normal. The rates of uptake and degradation of an exogenous protein were determined in normal and beige mice by intravenously injecting 125I-bovine serum albumin and following, in peripheral blood, the loss with time of phosphotungstic acid-insoluble bovine serum albumin and the parallel appearance of phosphotungstic acid-soluble (degraded) material. No significant differences were observed between beige and normal mice in the uptake by liver lysosomes of 125I-bovine serum albumin (t½ = 3.9 and 2.8 h, respectively). However, it was found that lysosomes from livers of beige mice released phosphotungstic acid-soluble radioactivity at a rate significantly slower than normal (t½ = 6.8 and 3.1 h, respectively). This defect in beige mice could be corrected by chronic administration of carbamyl choline (t½ = 3.5 h), a cholinergic agonist which raises intracellular cyclic GMP levels. However, no significant differences between normal and beige mice were observed either in the ability of soluble extracts of liver and kidney to bind [3H]cyclic GMP in vitro or in the basal levels of cyclic AMP in both tissues. The relevance of these observations to the presumed biochemical defect underlying the Chediak-Higashi syndrome is discussed. PMID:202611

Serum LH and FSH Responses to Synthetic LH-RH in Normal Infants, Children and Patients With Turner's Syndrome

ERIC Educational Resources Information Center

Suwa, Seizo; And Others

1974-01-01

Effects of luteinizing hormone-releasing hormone (LH-RH) on LH and follicle-stimulating hormone (FSH) release were studied in 26 normal children and six patients (from 1-to 14-years-old) with Turner's syndrome. (Author)

Quantitative Measurements of Electronically Excited CH Concentration in Normal Gravity and Microgravity Coflow Laminar Diffusion Flames

NASA Technical Reports Server (NTRS)

Giassi, D.; Cao, S.; Stocker, D. P.; Takahashi, F.; Bennett, B. A. V.; Smooke, M. D.; Long, M. B.

2015-01-01

With the conclusion of the SLICE campaign aboard the ISS in 2012, a large amount of data was made available for the analysis of the effect of microgravity on laminar coflow diffusion flames. Previous work focused on the study of sooty flames in microgravity as well as the ability of numerical models to predict its formation in a simplified buoyancy-free environment. The current work shifts the investigation to soot-free flames, putting an emphasis on the chemiluminescence emission from electronically excited CH (CH*). This radical species is of significant interest in combustion studies: it has been shown that the electronically excited CH spatial distribution is indicative of the flame front position and, given the relatively simple diagnostic involved with its measurement, several works have been done trying to understand the ability of electronically excited CH chemiluminescence to predict the total and local flame heat release rate. In this work, a subset of the SLICE nitrogen-diluted methane flames has been considered, and the effect of fuel and coflow velocity on electronically excited CH concentration is discussed and compared with both normal gravity results and numerical simulations. Experimentally, the spectral characterization of the DSLR color camera used to acquire the flame images allowed the signal collected by the blue channel to be considered representative of the electronically excited CH emission centered around 431 nm. Due to the axisymmetric flame structure, an Abel deconvolution of the line-of-sight chemiluminescence was used to obtain the radial intensity profile and, thanks to an absolute light intensity calibration, a quantification of the electronically excited CH concentration was possible. Results show that, in microgravity, the maximum flame electronically excited CH concentration increases with the coflow velocity, but it is weakly dependent on the fuel velocity; normal gravity flames, if not lifted, tend to follow the same trend, albeit with different peak concentrations. Comparisons with numerical simulations display reasonably good agreement between measured and computed flame lengths and radii, and it is shown that the integrated electronically excited CH emission scales proportionally to the computed total heat release rate; the two-dimensional electronically excited CH spatial distribution, however, does not appear to be a good marker for the local heat release rate.

Effect of progesterone concentration and duration of proestrus on fertility in beef cattle after fixed-time artificial insemination.

PubMed

Dadarwal, D; Mapletoft, R J; Adams, G P; Pfeifer, L F M; Creelman, C; Singh, J

2013-03-15

The objective was to determine the effect of plasma progesterone concentration and the duration of proestrus during growth of the ovulatory follicle on fertility in beef cattle. Heifers (N = 61) and postpartum cows (N = 79) were assigned randomly to four groups in a two-by-two design involving luteal-phase versus subluteal-phase plasma progesterone concentrations and normal versus short proestrus. To synchronize follicular wave emergence, estradiol-17β was given im during the midluteal phase (Day 0) and concurrently, a once-used controlled intravaginal progesterone-releasing device was placed intravaginally. In the subluteal-phase progesterone groups, a luteolytic dose of PGF(2α) was given on Day 0 and again 12 hours later. In the luteal-phase progesterone groups, PGF(2α) was not given (so as to retain a functional CL). The controlled intravaginal progesterone-releasing device was removed and PGF(2α) was given on Days 7 or 8 in the normal- and short-proestrus groups, respectively. Cattle were given lutropin im 12 or 36 hours later in the short- and normal-proestrus groups, respectively, with AI at 12 hours after lutropin treatment. Transrectal ultrasonography was used to monitor ovarian response during treatments and to diagnose pregnancy 60 days after AI. Cattle (heifers and cows combined) in the subluteal-phase progesterone groups and normal proestrus groups had a larger follicle at the time of AI, and a larger CL that secreted more progesterone 9 days after AI than cattle with luteal-phase progesterone concentrations or those with short proestrus (P < 0.03). There was a higher incidence of ovulation (P < 0.01) the day after AI in heifers (55/61; 90%) than in cows (44/79; 56%). Pregnancy rates ranged from 11% to 54%, and were higher in cattle (heifers and cows combined) in the subluteal-phase progesterone groups and normal proestrus groups than in the luteal-phase progesterone or short proestrus groups, respectively, (P < 0.02). In conclusion, a short proestrous interval reduced pregnancy rate after fixed-time AI in beef cattle. A low progesterone environment during growth of the ovulatory follicle increased the preovulatory follicle size and subsequent CL size and function, and compensated for the effect of a short proestrus on pregnancy rates. Copyright © 2013 Elsevier Inc. All rights reserved.

Altered neuroendocrine regulation of gonadotropin secretion in women distance runners.

PubMed

Veldhuis, J D; Evans, W S; Demers, L M; Thorner, M O; Wakat, D; Rogol, A D

1985-09-01

We tested the hypothesis that the neuroendocrine control of gonadotropin secretion is altered in certain women distance runners with secondary amenorrhea. To this end, we quantitated the frequency and amplitude of spontaneous pulsatile LH secretion during a 24-h interval in nine such women. The ability of the pituitary gland to release LH normally was assessed by administration of graded bolus doses of GnRH during the subsequent 8 h. Compared to normally menstruating women, six of nine amenorrheic distance runners had a distinct reduction in spontaneous LH pulse frequency, with one, three, six, five, four, or two pulses per 24 h (normal, 8-15 pulses/24 h). This reduction in LH pulse frequency occurred without any significant alterations in plasma concentrations of estradiol and free testosterone or 24-h integrated serum concentrations of LH, FSH, or PRL. Moreover, in long-distance runners, the capacity of the pituitary gland to release LH was normal or accentuated in response to exogenous pulses of GnRH. In the six women athletes with diminished spontaneous LH pulsatility, acute ovarian responsiveness also was normal, since serum estradiol concentrations increased normally in response to the GnRH-induced LH pulses. Although long-distance runners had significantly lower estimated percent body fat compared to control women, specific changes in pulsatile gonadotropin release did not correlate with degree of body leanness. In summary, certain long-distance runners with secondary amenorrhea or severe oligomenorrhea have unambiguously decreased spontaneous LH pulse frequency with intact pituitary responsiveness to GnRH. This neuroendocrine disturbance may be relevant to exercise-associated amenorrhea, since pulsatile LH release is a prerequisite for cyclic ovarian function. We speculate that such alterations in pulsatile LH release in exercising women reflect an adaptive response of the hypothalamic pulse generator controlling the intermittent GnRH signal to the pituitary gland. The basis for amenorrhea in the remaining runners who have normal pulsatile properties of LH release is not known.

Citizen science data suggest that a novel rig improves landing rate and reduces injury and handling time in recreational angling with artificial lures in Baltic pike (Esox lucius).

PubMed

Bursell, Jens Jakob; Arlinghaus, Robert

2018-01-01

The optimal terminal gear in hook-and-line recreational fishing maximizes landing rates and minimizes injury to the fish because some fish will be released after capture. We designed a novel rig configuration in artificial lure fishing for top predators and examined its effectiveness in angling for Baltic northern pike ( Esox lucius ) using a citizen science approach based on observational data collected from volunteer anglers in the field. The novel rig included two changes to traditional rig designs common to artificial lure angling. First, hooks were mounted in a way giving better hook exposure and eliminating lever-arm effects from the lure to the hooks once a fish is hooked. This construction allowed the second change, being a shift to hooks 4-5 sizes smaller than those used on traditional hook mounts. We analysed observational data collected by volunteer anglers using either the novel rig or a standard rig mount in two types of artificial lures (softbait and hardbait) of the same size (about 17 cm). Using N  = 768 pike contacts as input data, we showed the landing rates of pike targeted with artificial lures significantly and substantially increased from 45% with normal-rigs to 85% when the same lure types were fished with the novel rig configuration. Lure type and water temperature had no effects on landing rates. Moreover, hardbaits on normal-rigs produced significantly more injury, bleeding and elevated unhooking time compared to fish captured on hardbaits with release-rigs. We conclude that simple changes to traditional hook sizes and mounts in lure fishing may benefit both anglers and the fishes that are to be released and that citizen science projects with volunteer anglers are able to provide good data in proof-of-concept studies. Further experimental studies are needed to differentiate hook size from hook mount effects because both variables were confounded in the results of the observational data presented here.

Effects of Mg2+ on Ca2+ release from sarcoplasmic reticulum of skeletal muscle fibres from yabby (crustacean) and rat.

PubMed

Launikonis, B S; Stephenson, D G

2000-07-15

1. The role of myoplasmic [Mg2+] on Ca2+ release from the sarcoplasmic reticulum (SR) was examined in the two major types of crustacean muscle fibres, the tonic, long sarcomere fibres and the phasic, short sarcomere fibres of the fresh water decapod crustacean Cherax destructor (yabby) and in the fast-twitch rat muscle fibres using the mechanically skinned muscle fibre preparation. 2. A robust Ca2+-induced Ca2+-release (CICR) mechanism was present in both long and short sarcomere fibres and 1 mM Mg2+ exerted a strong inhibitory action on the SR Ca2+ release in both fibre types. 3. The SR displayed different properties with respect to Ca2+ loading in the long and the short sarcomere fibres and marked functional differences were identified with respect to Mg2+ inhibition between the two crustacean fibre types. Thus, in long sarcomere fibres, the submaximally loaded SR was able to release Ca2+ when [Mg2+] was lowered from 1 to 0.01 mM in the presence of 8 mM ATPtotal and in the virtual absence of Ca2+ (< 5 nM) even when the CICR was suppressed. In contrast, negligible Ca2+ was released from the submaximally loaded SR of short sarcomere yabby fibres when [Mg2+] was lowered from 1 to 0.01 mM under the same conditions as for the long sarcomere fibres. Nevertheless, the rate of SR Ca2+ release in short sarcomere fibres increased markedly when [Mg2+] was lowered in the presence of [Ca2+] approaching the normal resting levels (50-100 nM). 4. Rat fibres were able to release SR Ca2+ at a faster rate than the long sarcomere yabby fibres when [Mg2+] was lowered from 1 to 0. 01 mM in the virtual absence of Ca2+ but, unlike with yabby fibres, the net rate of Ca2+ release was actually increased for conditions that were considerably less favourable to CICR. 5. In summary, it is concluded that crustacean skeletal muscles have more that one functional type of Ca2+-release channels, that these channels display properties that are intermediate between those of mammalian skeletal and cardiac isoforms, that the inhibition exerted by Mg2+ at rest on the crustacean SR Ca2+-release channels must be removed during excitation-contraction coupling and that, unlike in crustacean fibres, CICR cannot play the major role in the activation of SR Ca2+-release channels in the rat skeletal muscle.

Effect of flow rate and lead/copper pipe sequence on lead release from service lines.

PubMed

Cartier, Clément; Arnold, Roger B; Triantafyllidou, Simoni; Prévost, Michèle; Edwards, Marc

2012-09-01

A pilot experiment examined lead leaching from four representative configurations of service lines including: (1) 100% lead (Pb), (2) 100% copper (Cu), (3) 50% Pb upstream of 50% Cu, and (4) 50% Pb-downstream of 50% Cu using a range of flow rates. The cumulative mass of lead release indicated that a typical partial replacement configuration (50% lead downstream of copper) did not provide a net reduction in lead when compared to 100% lead pipe (85 mg for 50% Pb-downstream versus 83 mg for 100%-Pb) due to galvanic and deposition corrosion. The partially replaced service line configuration also had a much greater likelihood of producing water with "spikes" of lead particulates at higher flow rates, while tending to produce lower levels of lead at very low flow rates. After the first 214 days the galvanic current between copper and lead was only reduced by 34%, proving that galvanic impacts can be highly persistent even in water with optimized corrosion control by dosing of zinc orthophosphate. Finally, this experiment raises concern about the low flow rates used during some prior home sampling events, which may underestimate exposure to lead during normal water use, especially when galvanic Pb:Cu connections are present. Copyright © 2012 Elsevier Ltd. All rights reserved.

Stress does not affect ghrelin secretion in obese and normal weight women.

PubMed

Kiessl, Gundula R R; Laessle, Reinhold G

2017-03-01

Stress has been supposed to increase appetite. The biological basis of this phenomenon may be a stress-induced alteration of the secretion of GUT peptides such as ghrelin. Stress-induced changes in ghrelin secretion could be a biological basis of overeating and a factor contributing to the development of obesity. Aim of the study was to analyze the effect of acute psychosocial stress on ghrelin secretion in obese and normal weight women. We compared pre- and postprandial plasma ghrelin secretion of 42 obese and 43 normal weight women in a randomized crossover design. Ghrelin and cortisol concentrations were measured and ratings of stress were also recorded in response to a psychological stressor (Trier Social Stress Test, TSST). Ghrelin samples were collected in the fasting state one time before participating in the TSST and one time before a control session. After the TSST, respectively, control session participants had a standardized ad libitum meal. 30 and 60 min after the TSST, respectively, control session preprandial ghrelin was measured again. Obese women showed lower pre- and postprandial release of ghrelin than normal weight controls. Moreover, obese women showed inhibited postprandial decrease of ghrelin secretion. Stress did not affect postprandial ghrelin secretion, but inhibited food intake in all subjects. The present data provide further evidence of altered ghrelin release in obesity. Acute stress did not affect postprandial ghrelin secretion, but inhibited food intake in all subjects. Results are discussed with regard to biological and psychological regulation of hunger and satiety in obesity.

Forearm vasodilatation following release of venous congestion

PubMed Central

Caro, C. G.; Foley, T. H.; Sudlow, M. F.

1970-01-01

1. The volume rate of forearm blood flow was measured with a mercury-in-rubber strain gauge, or with a water-filled plethysmograph, from 1 sec after termination of a 2-3 min period of venous congestion. 2. When congesting pressure had been less than 18 mm Hg, average post-congestion flow (five subjects) was constant during approx. 10 sec and not significantly different from resting flow. 3. When congesting pressure had been 30 mm Hg, average post-congestion flow (eight subjects) was 26% higher than resting, during 3-4 sec after release of congestion, but rose to 273% of resting during 4-6 sec after release of congestion. 4. In other studies forearm vascular resistance had been found normal or increased during such venous congestion, and theoretical studies here indicated that passive mechanical factors could not account for the delayed occurrence of high post-congestion flow. 5. It appears, therefore, that the forearm vascular bed dilates actively shortly after release of substantial venous congestion. It would seem more likely that a myogenic mechanism, rather than a metabolic one, is responsible. PMID:5532541

Measurement of IL-13–Induced iNOS-Derived Gas Phase Nitric Oxide in Human Bronchial Epithelial Cells

PubMed Central

Suresh, Vinod; Mih, Justin D.; George, Steven C.

2007-01-01

Exhaled nitric oxide (NO) is altered in numerous diseases including asthma, and is thought broadly to be a noninvasive marker of inflammation. However, the precise source of exhaled NO has yet to be identified, and the interpretation is further hampered by significant inter-subject variation. Using fully differentiated normal human bronchial epithelial (NHBE) cells, we sought to determine (1) the rate of NO release (flux, pl·s−1.cm−2) into the gas; (2) the effect of IL-13, a prominent mediator of allergic inflammation, on NO release; and (3) inter-subject/donor variability in NO release. NHBE cells from three different donors were cultured at an air–liquid interface and stimulated with different concentrations of IL-13 (0, 1, and 10 ng/ml) for 48 h. Gas phase NO concentrations in the headspace over the cells were measured using a chemiluminescence analyzer. The basal NO flux from the three donors (0.05 ± 0.03) is similar in magnitude to that estimated from exhaled NO concentrations, and was significantly increased by IL-13 in a donor-specific fashion. The increase in NO release was strongly correlated with inducible nitric oxide synthase (iNOS) gene and protein expression. There was a trend toward enhanced production of nitrate relative to nitrite as an end product of NO metabolism in IL-13–stimulated cells. NO release from airway epithelial cells can be directly measured. The rate of release in response to IL-13 is strongly dependent on the individual donor, but is primarily due to the expression of iNOS. PMID:17347445

Interaction between protein kinase C and protein kinase A can modulate transmitter release at the rat neuromuscular synapse.

PubMed

Santafé, M M; Garcia, N; Lanuza, M A; Tomàs, M; Tomàs, J

2009-02-15

We used intracellular recording to investigate the functional interaction between protein kinase C (PKC) and protein kinase A (PKA) signal transduction cascades in the control of transmitter release in the neuromuscular synapses from adult rats. Our results indicate that: 1) PKA and PKC are independently involved in asynchronous release. 2) Evoked acetylcholine (ACh) release is enhanced with the PKA agonist Sp-8-BrcAMP and the PKC agonist phorbol ester (PMA). 3) PKA has a constitutive role in promoting a component of normal evoked transmitter release because, when the kinase is inhibited with H-89, the release diminishes. However, the PKC inhibitor calphostin C (CaC) does not affect ACh release. 4) PKA regulates neurotransmission without PKC involvement because, after PMA or CaC modulation of the PKC activity, coupling to the ACh release of PKA can normally be stimulated with Sp-8-BrcAMP or inhibited with H-89. 5) After PKA inhibition with H-89, PKC stimulation with PMA (or inhibition with CaC) does not lead to any change in evoked ACh release. However, in PKA-stimulated preparations with Sp-8-BrcAMP, PKC becomes tonically active, thus potentiating a component of release that can now be blocked with CaC. In normal conditions, therefore, PKA was able to modulate ACh release independently of PKC activity, whereas PKA stimulation caused the PKC coupling to evoked release. In contrast, PKA inhibition prevent PKC stimulation (with the phorbol ester) and coupling to ACh output. There was therefore some dependence of PKC on PKA activity in the fine control of the neuromuscular synaptic functionalism and ACh release.

Doxorubicin-conjugated mesoporous magnetic colloidal nanocrystal clusters stabilized by polysaccharide as a smart anticancer drug vehicle.

PubMed

Li, Dian; Tang, Jing; Wei, Chuan; Guo, Jia; Wang, Shilong; Chaudhary, Deeptangshu; Wang, Changchun

2012-09-10

Fabrication of magnetic nanocarriers that demonstrate enhanced biocompatibility and excellent colloidal stability is critical for the application of magnetic-motored drug delivery, and it remains a challenge. Herein, a novel approach to synthesize mesoporous magnetic colloidal nanocrystal clusters (MMCNCs) that are stabilized by agarose is described; these clusters demonstrate high magnetization, large surface area and pore volume, excellent colloidal stability, enhanced biocompatibility, and acid degradability. The hydroxyl groups of agarose, which cover the surface of the magnetic nanocrystals, are modified with vinyl groups, followed by click reaction with mercaptoacetyl hydrazine to form the terminal hydrazide (-CONHNH(2)). The anticancer agent doxorubicin (DOX) is then conjugated to MMCNCs through a hydrazone bond. The resulting hydrazone is acid cleavable, thereby providing a pH-sensitive drug release capability. This novel carrier provides an important step towards the construction of a new family of magnetic-motored drug-delivery systems. The experimental results show that the release rate of DOX from the DOX-conjugated MMCNCs (MMCNCs-DOX) is dramatically improved at low pH (tumor cell: pH 4-5 in the late stage of endolysosome and pH 5-6 from the early to late endosome), while almost no DOX is released at neutral pH (blood plasma). The cell cytotoxicity of the MMCNCs-DOX measured by MTT assay exhibits a comparable antitumor efficacy but lower cytotoxicity for normal cell lines, when measured against the free drug, thus achieving the aim of reducing side effects to normal tissues associated with controlled drug release. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Glucose-lowering effect of BTS 67 582.

PubMed

Page, T; Bailey, C J

1997-12-01

1. The hypoglycaemic effect of BTS 67 582 (1,1-dimethyl-2(2-morpholinophenyl) guanidine fumarate) was studied in normal rats. 2. BTS 67 582 (100 mg kg(-1), p.o.) acutely lowered basal plasma glucose concentrations: onset within 1 h, maximum decrease of >40% at 2-3 h, and partial return to euglycaemia by 5 h. Plasma insulin concentrations were increased: onset within 30 min, maximum increase 3 fold at 1-2 h; returning to normal by 5 h. 3. BTS 67 582 (100 mg kg(-1)) increased (by 56%) the rate of disappearance of plasma glucose during an intravenous glucose tolerance test, accompanied by a 51% increase in insulin concentrations. 4. During hyperglycaemic clamp studies BTS 67 582 (100 mg kg(-1)) increased glucose utilization 3 fold. This was associated with a 3 fold increase in insulin concentrations, even in the presence of adrenaline at a dosage which inhibits glucose-induced insulin release. 5. When the insulin-releasing effect of BTS 67 582 (100 mg kg(-1)) was inhibited by infusion of somatostatin, there was no effect on glycaemia. 6. Insulin-dependent diabetic BB/S rats, which do not produce endogenous insulin, showed no effect of BTS 67 582 (100 mg kg(-1)) on plasma glucose concentrations in the presence or absence of exogenous insulin. 7. The results demonstrate an acute hypoglycaemic effect of BTS 67 582 which appears to result mainly from its potent insulin-releasing action.

Silver release from nanocomposite Ag/alginate hydrogels in the presence of chloride ions: experimental results and mathematical modeling

NASA Astrophysics Data System (ADS)

Kostic, Danijela; Vidovic, Srđan; Obradovic, Bojana

2016-03-01

A stepwise experimental and mathematical modeling approach was used to assess silver release from nanocomposite Ag/alginate microbeads in wet and dried forms into water and into normal saline solution chosen as a simplified model for certain biological fluids (e.g., blood plasma, wound exudates, sweat, etc). Three phenomena were connected and mathematically described: diffusion of silver nanoparticles (AgNPs) within the alginate hydrogel, AgNP oxidation/dissolution and reaction with chloride ions, and diffusion of the resultant silver-chloride species. Mathematical modeling results agreed well with the experimental data with the AgNP diffusion coefficient estimated as 1.3 × 10-18 m2 s-1, while the first-order kinetic rate constant of AgNP oxidation/dissolution and diffusivity of silver-chloride species were shown to be inversely related. In specific, rapid rehydration and swelling of dry Ag/alginate microbeads induced fast AgNP oxidation/dissolution reaction with Cl- and AgCl precipitation within the microbeads with the lowest diffusivity of silver-chloride species compared to wet microbeads in normal saline. The proposed mathematical model provided an insight into the phenomena related to silver release from nanocomposite Ca-alginate hydrogels relevant for use of antimicrobial devices and established, at the same time, a basis for further in-depth studies of AgNP interactions in hydrogels in the presence of chloride ions.

Light-induced protoporphyrin release from erythrocytes in erythropoietic protoporphyria.

PubMed Central

Sandberg, S; Brun, A

1982-01-01

The photohemolysis of normal erythrocytes incubated with protoporphyrin is reduced in the presence of albumin. When globin is added to normal erythrocytes loaded with protoporphyrin, protoporphyrin is bound to globin. During irradiation protoporphyrin moves from globin to the erythrocyte membrane and photohemolysis is initiated. Erythrocytes in patients with erythropoietic protoporphyria contain large amounts of protoporphyrin bound to hemoglobin. Upon irradiation of these cells in the absence of albumin, 40% of protoporphyrin and 80% of hemoglobin is released after 240 kJ/m2. The released protoporphyrin is hemoglobin bound. In contrast, when albumin is present only 8% of hemoglobin is released whereas protoporphyrin is released to 76%. The released protoporphyrin is albumin bound. A hypothesis for the release of erythrocyte protoporphyrin in erythropoietic protoporphyria without simultaneous hemolysis is proposed. Upon irradiation protoporphyrin photodamages its binding sites on hemoglobin, moves through the plasma membrane, and is bound to albumin in plasma. PMID:7107898

A Monte Carlo program to calculate the exposure rate from airborne radioactive gases inside a nuclear reactor containment building.

PubMed

Sherbini, S; Tamasanis, D; Sykes, J; Porter, S W

1986-12-01

A program was developed to calculate the exposure rate resulting from airborne gases inside a reactor containment building. The calculations were performed at the location of a wall-mounted area radiation monitor. The program uses Monte Carlo techniques and accounts for both the direct and scattered components of the radiation field at the detector. The scattered component was found to contribute about 30% of the total exposure rate at 50 keV and dropped to about 7% at 2000 keV. The results of the calculations were normalized to unit activity per unit volume of air in the containment. This allows the exposure rate readings of the area monitor to be used to estimate the airborne activity in containment in the early phases of an accident. Such estimates, coupled with containment leak rates, provide a method to obtain a release rate for use in offsite dose projection calculations.

Elasticity Solution of an Adhesively Bonded Cover Plate of Various Geometries

NASA Technical Reports Server (NTRS)

Aksel, G. N.; Erdogan, F.

1985-01-01

The plane strain of adhesively bonded structures consisting of two different isotropic adherends is considered. By expressing the x-y components of the displacements in terms of Fourier integrals and using the corresponding boundary and continuity conditions, the integral equations for the general problem are obtained and solved numerically by applying Gauss-Chebyshev integration scheme. The shear and the normal stresses in the adhesive are calculated for various geometries and material properties for a stiffened plate under uniaxial tension. Numerical results involving the stress intensity factors and the strain energy release rate are presented. The closed-form expressions for the Fredholm kernels are provided to obtain the solution for an arbitrary geometry and material properties. For the general geometry, the contribution of the normal stress is quite significant, while for symmetric geometries, the shear stress is dominant, the normal stress vanishes if the adherends are of the same material and the same thickness.

Fingerprinting Breast Cancer vs. Normal Mammary Cells by Mass Spectrometric Analysis of Volatiles

NASA Astrophysics Data System (ADS)

He, Jingjing; Sinues, Pablo Martinez-Lozano; Hollmén, Maija; Li, Xue; Detmar, Michael; Zenobi, Renato

2014-06-01

There is increasing interest in the development of noninvasive diagnostic methods for early cancer detection, to improve the survival rate and quality of life of cancer patients. Identification of volatile metabolic compounds may provide an approach for noninvasive early diagnosis of malignant diseases. Here we analyzed the volatile metabolic signature of human breast cancer cell lines versus normal human mammary cells. Volatile compounds in the headspace of conditioned culture medium were directly fingerprinted by secondary electrospray ionization-mass spectrometry. The mass spectra were subsequently treated statistically to identify discriminating features between normal vs. cancerous cell types. We were able to classify different samples by using feature selection followed by principal component analysis (PCA). Additionally, high-resolution mass spectrometry allowed us to propose their chemical structures for some of the most discriminating molecules. We conclude that cancerous cells can release a characteristic odor whose constituents may be used as disease markers.

Retrogradation of Maize Starch after High Hydrostatic Pressure Gelation: Effect of Amylose Content and Depressurization Rate.

PubMed

Yang, Zhi; Swedlund, Peter; Gu, Qinfen; Hemar, Yacine; Chaieb, Sahraoui

2016-01-01

High hydrostatic pressure (HHP) has been employed to gelatinize or physically modify starch dispersions. In this study, waxy maize starch, normal maize starch, and two high amylose content starch were processed by a HHP of the order of 600 MPa, at 25°C for 15min. The effect of HHP processing on the crystallization of maize starches with various amylose content during storage at 4°C was investigated. Crystallization kinetics of HHP treated starch gels were investigated using rheology and FTIR. The effect of crystallization on the mechanical properties of starch gel network were evaluated in terms of dynamic complex modulus (G*). The crystallization induced increase of short-range helices structures were investigated using FTIR. The pressure releasing rate does not affect the starch retrogradation behaviour. The rate and extent of retrogradation depends on the amylose content of amylose starch. The least retrogradation was observed in HHP treated waxy maize starch. The rate of retrogradation is higher for HHP treated high amylose maize starch than that of normal maize starch. A linear relationship between the extent of retrogradation (phase distribution) measured by FTIR and G* is proposed.

Retrogradation of Maize Starch after High Hydrostatic Pressure Gelation: Effect of Amylose Content and Depressurization Rate

PubMed Central

Yang, Zhi; Swedlund, Peter; Gu, Qinfen; Hemar, Yacine; Chaieb, Sahraoui

2016-01-01

High hydrostatic pressure (HHP) has been employed to gelatinize or physically modify starch dispersions. In this study, waxy maize starch, normal maize starch, and two high amylose content starch were processed by a HHP of the order of 600 MPa, at 25°C for 15min. The effect of HHP processing on the crystallization of maize starches with various amylose content during storage at 4°C was investigated. Crystallization kinetics of HHP treated starch gels were investigated using rheology and FTIR. The effect of crystallization on the mechanical properties of starch gel network were evaluated in terms of dynamic complex modulus (G*). The crystallization induced increase of short-range helices structures were investigated using FTIR. The pressure releasing rate does not affect the starch retrogradation behaviour. The rate and extent of retrogradation depends on the amylose content of amylose starch. The least retrogradation was observed in HHP treated waxy maize starch. The rate of retrogradation is higher for HHP treated high amylose maize starch than that of normal maize starch. A linear relationship between the extent of retrogradation (phase distribution) measured by FTIR and G* is proposed. PMID:27219066

Zero gravity and cardiovascular homeostasis. The relationship between endogenous hyperprolactinemia and plasma aldosterone

NASA Technical Reports Server (NTRS)

Haber, E.; Re, R. N.; Kourides, I. A.; Weihl, A. C.; Maloof, F.

1978-01-01

Prolactin, thyrotropin and aldosterone were measured by radioimmunoassay and plasma renin activity by the radioimmunoassay of angiotensin I in normal women before and after the intravenous injection of 200 micrograms of thyrotropin releasing hormone. Prolactin increased at 15 minutes following thyrotropin releasing hormone. Plasma renin activity was not different from control levels during the first hour following the administration of thyrotropin releasing hormone, nor did the plasma aldosterone concentration differ significantly from the control levels during this period. However, with upright posture, an increase in aldosterone and in plasma renin activity was noted, demonstrating a normal capacity to secrete aldosterone. Similarly, no change in aldosterone was seen in 9 patients with primary hypothyroidism given thyrotropin releasing hormone, despite the fact that the increase in prolactin was greater than normal. These data demonstrate that acutely or chronically elevated serum prolactin levels do not result in increased plasma aldosterone levels in humans.

Effect of compression wood on leaching of chromium, copper, and arsenic from CCA-C treated red pine (Pinus resinosa Ait.)

Treesearch

S. Nami. Kartal; Stan. Lebow

2000-01-01

In this study, the effect of compression wood formation on the release rate of chromium, copper, and arsenic elements from red pine (Pinus resinosa Ait) was investigated. Wood blocks from red pine containing compression and normal wood portions were treated with a 1.0% CCA-C solution and were then allowed to fix at 23 * 2*C (74 * 4*F) for 0, 6, 24, 48, 96, 192, and 336...

Exact solution of two collinear cracks normal to the boundaries of a 1D layered hexagonal piezoelectric quasicrystal

NASA Astrophysics Data System (ADS)

Zhou, Y.-B.; Li, X.-F.

2018-07-01

The electroelastic problem related to two collinear cracks of equal length and normal to the boundaries of a one-dimensional hexagonal piezoelectric quasicrystal layer is analysed. By using the finite Fourier transform, a mixed boundary value problem is solved when antiplane mechanical loading and inplane electric loading are applied. The problem is reduce to triple series equations, which are then transformed to a singular integral equation. For uniform remote loading, an exact solution is obtained in closed form, and explicit expressions for the electroelastic field are determined. The intensity factors of the electroelastic field and the energy release rate at the inner and outer crack tips are given and presented graphically.

[Nutrient use efficiency and yield-increasing effect of single basal application of rice specific controlled release fertilizer].

PubMed

Chen, Jiansheng; Xu, Peizhi; Tang, Shuanhu; Zhang, Fabao; Xie, Chunsheng

2005-10-01

A series of pot and field experiments and field demonstrations showed that in comparing with the commonly used specific-fertilizers containing same amounts of nutrients, single basal application of rice-specific controlled release fertilizer could increase the use efficiency of N and P by 12.2% - 22.7% and 7.0% - 35.0%, respectively in pot experiment, and the use efficiency of N by 17.1% in field experiment. In 167 field demonstrations successively conducted for 3 years in various rice production areas of Guangdong Province, single basal application of the fertilizer saved the application rate of N and P by 22.1% and 21.8%, respectively, and increased the yield by 8.2%, compared with normal split fertilization.

Effect of tank diameter on thermal behavior of gasoline and diesel storage tanks fires.

PubMed

Leite, Ricardo Machado; Centeno, Felipe Roman

2018-01-15

Studies on fire behavior are extremely important as they contribute in a firefighting situation or even to avoid such hazard. Experimental studies of fire in real scale are unfeasible, implying that reduced-scale experiments must be performed, and results extrapolated to the range of interest. This research aims to experimentally study the fire behavior in tanks of 0.04m, 0.20m, 0.40m, 0.80m and 4.28m diameter, burning regular gasoline or diesel oil S-500. The following parameters were here obtained: burning rates, burning velocities, heat release rates, flame heights, and temperature distributions adjacent to the tank. Such parameters were obtained for each tank diameter with the purpose of correlating the results and understanding the relationship of each parameter for the different geometrical scale of the tanks. Asymptotic results for larger tanks were found as (regular gasoline and diesel oil S-500, respectively): burning rates 0.050kg/(m 2 s) and 0.031kg/(m 2 s), burning velocities 4.0mm/min and 2.5mm/min, heat release rates per unit area 2200kW/m 2 and 1500kW/m 2 , normalized averaged flame heights (H i /D, where H i is the average flame height, D is the tank diameter) 0.9 and 0.8. Maximum temperatures for gasoline pools were higher than for diesel oil pools, and temperature gradients close to the tanks were also higher for the former fuel. The behavior of the maximum temperature was correlated as a function of the tank diameter, the heat release rate of each fuel and the dimensionless distance from the tank. Copyright © 2017 Elsevier B.V. All rights reserved.

Investigating the feasibility of temperature-controlled accelerated drug release testing for an intravaginal ring.

PubMed

Externbrink, Anna; Clark, Meredith R; Friend, David R; Klein, Sandra

2013-11-01

The objective of the present study was to investigate if temperature can be utilized to accelerate drug release from Nuvaring®, a reservoir type intravaginal ring based on polyethylene vinyl acetate copolymer that releases a constant dose of contraceptive steroids over a duration of 3 weeks. The reciprocating holder apparatus (USP 7) was utilized to determine real-time and accelerated etonogestrel release from ring segments. It was demonstrated that drug release increased with increasing temperature which can be attributed to enhanced drug diffusion. An Arrhenius relationship of the zero-order release constants was established, indicating that temperature is a valid parameter to accelerate drug release from this dosage form and that the release mechanism is maintained under these accelerated test conditions. Accelerated release tests are particularly useful for routine quality control to assist during batch release of extended release formulations that typically release the active over several weeks, months or even years, since they can increase the product shelf life. The accelerated method should therefore be able to discriminate between formulations with different release characteristics that can result from normal manufacturing variance. In the case of Nuvaring®, it is well known that the process parameters during the extrusion process strongly influence the polymeric structure. These changes in the polymeric structure can affect the permeability which, in turn, is reflected in the release properties. Results from this study indicate that changes in the polymeric structure can lead to a different temperature dependence of the release rate, and as a consequence, the accelerated method can become less sensitive to detect changes in the release properties. When the accelerated method is utilized during batch release, it is therefore important to take this possible restriction into account and to evaluate the accelerated method with samples from non-conforming batches that are explicitly "out of specification" under real-time test conditions. Copyright © 2013 Elsevier B.V. All rights reserved.

Time-dependent Mechanisms in Beta-cell Glucose Sensing

PubMed Central

Vagn Korsgaard, Thomas

2006-01-01

The relation between plasma glucose and insulin release from pancreatic beta-cells is not stationary in the sense that a given glucose concentration leads to a specific rate of insulin secretion. A number of time-dependent mechanisms appear to exist that modify insulin release both on a short and a longer time scale. Typically, two phases are described. The first phase, lasting up to 10 min, is a pulse of insulin release in response to fast changes in glucose concentration. The second phase is a more steady increase of insulin release over minutes to hours, if the elevated glucose concentration is sustained. The paper describes the glucose sensing mechanism via the complex dynamics of the key enzyme glucokinase, which controls the first step in glucose metabolism: phosphorylation of glucose to glucose-6-phosphate. Three time-dependent phenomena (mechanisms) are described. The fastest, corresponding to the first phase, is a delayed negative feedback regulating the glucokinase activity. Due to the delay, a rapid glucose increase will cause a burst of activity in the glucose sensing system, before the glucokinase is down-regulated. The second mechanism corresponds to the translocation of glucokinase from an inactive to an active form. As the translocation is controlled by the product(s) of the glucokinase reaction rather than by the substrate glucose, this mechanism gives a positive, but saturable, feedback. Finally, the release of the insulin granules is assumed to be enhanced by previous glucose exposure, giving a so-called glucose memory to the beta-cells. The effect depends on the insulin release of the cells, and this mechanism constitutes a second positive, saturable feedback system. Taken together, the three phenomena describe most of the glucose sensing behaviour of the beta-cells. The results indicate that the insulin release is not a precise function of the plasma glucose concentration. It rather looks as if the beta-cells just increase the insulin production, until the plasma glucose has returned to normal. This type of integral control has the advantage that the precise glucose sensitivity of the beta-cells is not important for normal glucose homeostasis. PMID:19669468

Development of Spatial Release from Masking in Mandarin-Speaking Children with Normal Hearing

ERIC Educational Resources Information Center

Yuen, Kevin C. P.; Yuan, Meng

2014-01-01

Purpose: This study investigated the development of spatial release from masking in children using closed-set Mandarin disyllabic words and monosyllabic words carrying lexical tones as test stimuli and speech spectrum-weighted noise as a masker. Method: Twenty-six children ages 4-9 years and 12 adults, all with normal hearing, participated in…

The SAMI Galaxy Survey: Publicly Available Spatially Resolved Emission Line Data Products

NASA Astrophysics Data System (ADS)

Medling, Anne; Green, Andrew W.; Ho, I.-Ting; Groves, Brent; Croom, Scott; SAMI Galaxy Survey Team

2017-01-01

The SAMI Galaxy Survey is collecting optical integral field spectroscopy of up to 3400 nearby (z<0.1) galaxies with a range of stellar masses and in a range of environments. The first public data release contains nearly 800 galaxies from the Galaxy And Mass Assembly (GAMA) Survey. In addition to releasing the reduced data cubes, we also provide emission line fits (flux and kinematic maps of strong emission lines including Halpha and Hbeta, [OII]3726,29, [OIII]4959,5007, [OI]6300, [NII]6548,83, and [SII]6716,31), extinction maps, star formation classification masks, and star formation rate maps. We give an overview of the data available for your favorite emission line science and present a few early science results. For example, a sample of edge-on disk galaxies show enhanced extraplanar emission related to SF-driven outflows, which are correlated with a bursty star formation history and higher star formation rate surface densities. Interestingly, the star formation rate surface densities of these wind hosts are 5-100 times lower than the canonical threshold for driving winds (0.1 MSun/yr/kpc2), indicating that galactic winds may be more important in normal star-forming galaxies than previously thought.

Impact of Release Rates on the Effectiveness of Augmentative Biological Control Agents

PubMed Central

Crowder, David W.

2007-01-01

To access the effect of augmentative biological control agents, 31 articles were reviewed that investigated the impact of release rates of 35 augmentative biological control agents on the control of 42 arthropod pests. In 64% of the cases, the release rate of the biological control agent did not significantly affect the density or mortality of the pest insect. Results where similar when parasitoidsor predators were utilized as the natural enemy. Within any order of natural enemy, there were more cases where release rates did not affect augmentative biological control than cases where release rates were significant. There were more cases in which release rates did not affect augmentative biological control when pests were from the orders Hemiptera, Acari, or Diptera, but not with pests from the order Lepidoptera. In most cases, there was an optimal release rate that produced effective control of a pest species. This was especially true when predators were used as a biological control agent. Increasing the release rate above the optimal rate did not improve control of the pest and thus would be economically detrimental. Lower release rates were of ten optimal when biological control was used in conjunction with insecticides. In many cases, the timing and method of biological control applications were more significant factors impacting the effectiveness of biological control than the release rate. Additional factors that may limit the relative impact of release rates include natural enemy fecundity, establishment rates, prey availability, dispersal, and cannibalism. PMID:20307240

Biodegradable drug-eluting nanofiber-enveloped implants for sustained release of high bactericidal concentrations of vancomycin and ceftazidime: in vitro and in vivo studies

PubMed Central

Hsu, Yung-Heng; Chen, Dave Wei-Chih; Tai, Chun-Der; Chou, Ying-Chao; Liu, Shih-Jung; Ueng, Steve Wen-Neng; Chan, Err-Cheng

2014-01-01

We developed biodegradable drug-eluting nanofiber-enveloped implants that provided sustained release of vancomycin and ceftazidime. To prepare the biodegradable nanofibrous membranes, poly(D,L)-lactide-co-glycolide and the antibiotics were first dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol. They were electrospun into biodegradable drug-eluting membranes, which were then enveloped on the surface of stainless plates. An elution method and a high-performance liquid chromatography assay were employed to characterize the in vivo and in vitro release rates of the antibiotics from the nanofiber-enveloped plates. The results showed that the biodegradable nanofiber-enveloped plates released high concentrations of vancomycin and ceftazidime (well above the minimum inhibitory concentration) for more than 3 and 8 weeks in vitro and in vivo, respectively. A bacterial inhibition test was carried out to determine the relative activity of the released antibiotics. The bioactivity ranged from 25% to 100%. In addition, the serum creatinine level remained within the normal range, suggesting that the high vancomycin concentration did not affect renal function. By adopting the electrospinning technique, we will be able to manufacture biodegradable drug-eluting implants for the long-term drug delivery of different antibiotics. PMID:25246790

Thermo-sensitively and magnetically ordered mesoporous carbon nanospheres for targeted controlled drug release and hyperthermia application.

PubMed

Chen, Lin; Zhang, Huan; Zheng, Jing; Yu, Shiping; Du, Jinglei; Yang, Yongzhen; Liu, Xuguang

2018-03-01

A multifunctional nanoplatform based on thermo-sensitively and magnetically ordered mesoporous carbon nanospheres (TMOMCNs) is developed for effective targeted controlled release of doxorubicin hydrochloride (DOX) and hyperthermia in this work. The morphology, specific surface area, porosity, thermo-stability, thermo-sensitivity, as well as magnetism properties of TMOMCNs were verified by high resolution transmission electron microscopy, field emission scanning electron microscopy, thermo-gravimetric analysis, X-ray diffraction, Brunauer-Emmeltt-Teller surface area analysis, dynamic light scattering and vibrating sample magnetometry measurement. The results indicate that TMOMCNs have an average diameter of ~146nm with a lower critical solution temperature at around 39.5°C. They are superparamagnetic with a magnetization of 10.15emu/g at 20kOe. They generate heat when inductive magnetic field is applied to them and have a normalized specific absorption rate of 30.23W/g at 230kHz and 290Oe, showing good potential for hyperthermia. The DOX loading and release results illustrate that the loading capacity is 135.10mg/g and release performance could be regulated by changing pH and temperature. The good targeting, DOX loading and release and hyperthermia properties of TMOMCNs offer new probabilities for high effectiveness and low toxicity of cancer chemotherapy. Copyright © 2017 Elsevier B.V. All rights reserved.

Mechanical Strength and Failure Characterization of Sn-Ag-Cu Intermetallic Compound Joints at the Microscale

NASA Astrophysics Data System (ADS)

Ladani, Leila; Razmi, Jafar

2012-03-01

Continuous miniaturization of microelectronic devices has led the industry to develop interconnects on the order of a few microns for advanced superhigh-density and three-dimensional integrated circuits (3D ICs). At this scale, interconnects that conventionally consist of solder material will completely transform to intermetallic compounds (IMCs) such as Cu6Sn5. IMCs are brittle, unlike conventional solder materials that are ductile in nature; therefore, IMCs do not experience large amounts of plasticity or creep before failure. IMCs have not been fully characterized, and their mechanical and thermomechanical reliability is questioned. This study presents experimental efforts to characterize such material. Sn-based microbonds are fabricated in a controlled environment to assure complete transformation of the bonds to Cu6Sn5 IMC. Microstructural analysis including scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS), and x-ray diffraction (XRD) is utilized to determine the IMC material composition and degree of copper diffusion into the bond area. Specimens are fabricated with different bond thicknesses and in different configurations for various tests. Normal strength of the bonds is measured utilizing double cantilever beam and peeling tests. Shear tests are conducted to quantify the shear strength of the material. Four-point bending tests are conducted to measure the fracture toughness and critical energy release rate. Bonds are fabricated in different sizes, and the size effect is investigated. The shear strength, normal strength, critical energy release rate, and effect of bond size on bond strength are reported.

Endocannabinoids control vesicle release mode at midbrain periaqueductal grey inhibitory synapses.

PubMed

Aubrey, Karin R; Drew, Geoffrey M; Jeong, Hyo-Jin; Lau, Benjamin K; Vaughan, Christopher W

2017-01-01

The midbrain periaqueductal grey (PAG) forms part of an endogenous analgesic system which is tightly regulated by the neurotransmitter GABA. The role of endocannabinoids in regulating GABAergic control of this system was examined in rat PAG slices. Under basal conditions GABAergic neurotransmission onto PAG output neurons was multivesicular. Activation of the endocannabinoid system reduced GABAergic inhibition by reducing the probability of release and by shifting release to a univesicular mode. Blockade of endocannabinoid system unmasked a tonic control over the probability and mode of GABA release. These findings provides a mechanistic foundation for the control of the PAG analgesic system by disinhibition. The midbrain periaqueductal grey (PAG) has a crucial role in coordinating endogenous analgesic responses to physiological and psychological stressors. Endocannabinoids are thought to mediate a form of stress-induced analgesia within the PAG by relieving GABAergic inhibition of output neurons, a process known as disinhibition. This disinhibition is thought to be achieved by a presynaptic reduction in GABA release probability. We examined whether other mechanisms have a role in endocannabinoid modulation of GABAergic synaptic transmission within the rat PAG. The group I mGluR agonist DHPG ((R,S)-3,5-dihydroxyphenylglycine) inhibited evoked IPSCs and increased their paired pulse ratio in normal external Ca 2+ , and when release probability was reduced by lowering Ca 2+ . However, the effect of DHPG on the coefficient of variation and kinetics of evoked IPSCs differed between normal and low Ca 2+ . Lowering external Ca 2+ had a similar effect on evoked IPSCs to that observed for DHPG in normal external Ca 2+ . The low affinity GABA A receptor antagonist TPMPA ((1,2,5,6-tetrahydropyridin-4-yl)methylphosphinic acid) inhibited evoked IPSCs to a greater extent in low than in normal Ca 2+ . Together these findings indicate that the normal mode of GABA release is multivesicular within the PAG, and that DHPG and lowering external Ca 2+ switch this to a univesicular mode. The effects of DHPG were mediated by mGlu5 receptor engagement of the retrograde endocannabinoid system. Blockade of endocannabinoid breakdown produced a similar shift in the mode of release. We conclude that endocannabinoids control both the mode and the probability of GABA release within the PAG. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

Pharmacokinetics of 2 Novel Formulations of Modified-Release Oral Testosterone Alone and With Finasteride in Normal Men With Experimental Hypogonadism

PubMed Central

Snyder, Christin N.; Clark, Richard V.; Caricofe, Ralph B.; Bush, Mark A.; Roth, Mara Y.; Page, Stephanie T.; Bremner, William J.; Amory, John K.

2011-01-01

Oral administration of testosterone might be useful for the treatment of testosterone deficiency. However, current “immediate-release” formulations of oral testosterone exhibit suboptimal pharmacokinetics, with supraphysiologic peaks of testosterone and its metabolite, dihydrotestosterone (DHT), immediately after dosing. To dampen these peaks, we have developed 2 novel modified-release formulations of oral testosterone designed to slow absorption from the gut and improve hormone delivery. We studied these testosterone formulations in 16 normal young men enrolled in a 2-arm, open-label clinical trial. Three hundred-mg and 600-mg doses of immediate-release and modified fast-release or slow-release formulations were administered sequentially to 8 normal men rendered hypogonadal by the administration of the gonadotropin-releasing hormone antagonist acyline. Blood for measurement of serum testosterone, DHT, and estradiol was obtained before and 0.5, 1, 2, 3, 4, 6, 8, 12, and 24 hours after each dose. A second group of 8 men was studied with the coadministration of 1 mg of the 5α-reductase inhibitor finasteride daily throughout the treatment period. Serum testosterone was increased with all formulations of oral testosterone. The modified slow-release formulation significantly delayed the postdose peaks of serum testosterone and reduced peak concentrations of serum DHT compared with the immediate-release formulation. The addition of finasteride further increased serum testosterone and decreased serum DHT. We conclude that the oral modified slow-release testosterone formulation exhibits superior pharmacokinetics compared with immediate-release oral testosterone both alone and in combination with finasteride. This formulation might have efficacy for the treatment of testosterone deficiency. PMID:20378927

Evidence for inhibitory nicotinic and facilitatory muscarinic receptors in cholinergic nerve terminals of the rat urinary bladder.

PubMed

Somogyi, G T; de Groat, W C

1992-02-01

Cholinergic prejunctional modulatory receptors on parasympathetic nerves in the rat urinary bladder were studied by measuring 3H-acetylcholine (ACh) release in muscle strips from the bladder body. Electrical field stimulation markedly increased 3H-ACh overflow in strips preloaded with 3H-choline. Oxotremorine (1 microM), an M2 receptor agonist and DMPP (10 microM) a nicotinic (N) receptor agonist decreased the release of ACh (50% and 55% respectively); whereas McN-A 343 (50 microM) an M1 receptor agonist increased the release (33%), indicating the presence of three types of modulatory receptors. The anticholinesterase agent, physostigmine in concentrations of 1, 5 and 25 microM and neostigmine (5 microM) increased ACh release (44-710%). However a low concentration of physostigmine (0.05 microM) decreased release. Pirenzepine, an M1 muscarinic antagonist or atropine blocked the increased ACh release in physostigmine-treated strips, but in normal strips pirenzepine did not change release and atropine increased release. McN-A 343 or prolonged application (15 min) of DMPP increased ACh release (376% and 391% respectively) in physostigmine-treated strips. The response to McN-A 343 was blocked by pirenzepine. d-Tubocurarine (DTC), a nicotinic receptor blocker, enhanced ACh release in the presence of physostigmine but proved to be ineffective in normal preparations. These findings suggest that all three cholinergic receptors (M1 facilitatory, N inhibitory and M2 inhibitory) are activated by endogenous ACh in physostigmine treated preparations whereas only M2-inhibitory receptors are activated in normal preparations. It will be important in future studies to determine whether M1 and M2 mechanisms can also be activated under more physiological conditions in the bladder and whether they are present at other cholinergic synapses.

Impact of iron chelators on short-term dissolution of basaltic glass

NASA Astrophysics Data System (ADS)

Perez, Anne; Rossano, Stéphanie; Trcera, Nicolas; Verney-Carron, Aurélie; Huguenot, David; van Hullebusch, Eric D.; Catillon, Gilles; Razafitianamaharavo, Angelina; Guyot, François

2015-08-01

Although microorganisms seem to play an important role in the alteration processes of basaltic glasses in solution, the elementary mechanisms involved remain unclear in particular with regard to the role of organic ligands excreted by the cells. Two glasses, one with Fe and one without Fe were synthesized to model basaltic glass compositions. Fe in the glass was mostly Fe(III) for enhancing interaction with siderophores, yet with small but significant amounts of Fe(II) (between 10% and 30% of iron). The prepared samples were submitted to abiotic alteration experiments in buffered (pH 6.4) diluted solutions of metal-specific ligands, namely oxalic acid (OA, 10 mM), desferrioxamine (DFA, 1 mM) or 2,2‧-bipyridyl (BPI, 1 mM). Element release from the glass into the solution after short term alteration (maximum 1 week) was measured by ICP-OES, and normalized mass losses and relative release ratios (with respect to Si) were evaluated for each element in each experimental condition. The presence of organic ligands had a significant effect on the dissolution of both glasses. Trivalent metals chelators (OA, DFA) impacted on the release of Fe3+ and Al3+, and thus on the global dissolution of both glasses, enhancing all release rates and dissolution stoichiometry (release rates were increased up to 7 times for Al or Fe). As expected, the mostly divalent metal chelator BPI interacted preferentially with Ca2+, Mg2+ and Fe2+. This study thus allows to highlight the central roles of iron and aluminium in interaction with some organic ligands in the alteration processes of basaltic glasses. It thus provides a step toward understanding the biological contribution of this fundamental geological process.

Comparison of dual trigger with combination GnRH agonist and hCG versus hCG alone trigger of oocyte maturation for normal ovarian responders.

PubMed

Zhou, Xingyu; Guo, Pingping; Chen, Xin; Ye, Desheng; Liu, Yudong; Chen, Shiling

2018-06-01

To investigate whether dual triggering of oocyte maturation with a gonadotropin-releasing hormone (GnRH) agonist and standard dose of human chorionic gonadotropin (hCG) can improve clinical outcomes for normal ovarian responders in GnRH antagonist cycles. The present retrospective cohort study included women aged up to 40 years with normal ovarian response who underwent in vitro fertilization and/or intracytoplasmic sperm injection under the GnRH antagonist protocol at Nanfang Hospital, China, between January 1 and December 31, 2015. Patients were grouped by whether oocyte maturation was triggered with GnRH agonist plus 5000-10 000 IU of hCG (dual trigger) or hCG alone. The primary outcome was live delivery rate. There were 325 women included; 224 in the dual trigger group and 101 in the hCG alone group. The live delivery rate did not differ significantly between the groups (P=0.083). The mean number of retrieved oocytes was similar in the two groups (P=0.719), but the mean number of two-pronuclear embryos (P=0.004), the mean number of embryos available (P=0.001), and the mean number of high-quality embryos (P=0.011) was higher in the dual trigger group. Dual trigger of oocyte maturation was not associated with any change in the live delivery rate but was associated with improvements in the quantity and quality of embryos; it could optimize pregnancy outcomes for normal ovarian responders. © 2018 International Federation of Gynecology and Obstetrics.

Divergent effects of bombesin and bethanechol on stimulated gastric secretion in duodenal ulcer and in normal men.

PubMed

Helman, C A; Hirschowitz, B I

1987-06-01

To further investigate differences in the responses of normals and patients with duodenal ulcer with respect to gastrin release and acid and pepsin secretion, we infused bombesin (1 microgram/kg X h) or bethanechol (40 micrograms/kg X h) during the middle hour of a 3-h infusion of pentagastrin and compared the results with a pentagastrin infusion without added drug. Pentagastrin dosage (0.1 microgram/kg X h) was set to give about half-maximal response, to detect either inhibition or further stimulation of gastric secretion, whereas the dose of bombesin was chosen to give maximal gastrin but less than maximal acid secretion. Serum gastrin and somatostatin were also measured. In all subjects tested, bethanechol produced no effects on acid, gastrin, or somatostatin release but increased pepsin output. By contrast, bombesin inhibited pentagastrin-stimulated acid output in all 6 normal men by an average of 55%, whereas it inhibited acid output in only 2 of the 9 men with duodenal ulcer. Serum gastrin increases after bombesin in duodenal ulcer were three to four times greater than in normals. Although bombesin stimulates acid only by releasing gastrin, we postulate that bombesin may also simultaneously limit acid and pepsin secretion and speculate that this effect could be mediated by bombesin-induced somatostatin release. The cause for differences between duodenal ulcer and normal remain speculative.

Apoptosis may determine the release of skeletal alkaline phosphatase activity from human osteoblast-line cells.

PubMed

Farley, J R; Stilt-Coffing, B

2001-01-01

Although quantitative measurement of skeletal alkaline phosphatase (sALP) activity in serum can provide an index of the rate of bone formation, the metabolic process that determines the release of sALP - from the surface of osteoblasts, into circulation-is unknown. The current studies were intended to examine the hypothesis that the release of sALP from human osteoblasts is a consequence of apoptotic cell death. We measured the release of sALP activity from human osteosarcoma (SaOS-2) cells and normal human bone cells, under basal conditions and in response to agents that increased apoptosis (TNF-a, okadiac acid) and agents that inhibit apoptosis (IGF-I, calpain, and caspase inhibitors). Apoptosis was determined by the presence of nucleosomes (histone-associated DNA) in the cytoplasm of the cells by using a commercial kit. The results of these studies showed that TNF-a and okadiac acid caused dose- and time-dependent increases in apoptosis in the SaOS-2 cells (r = 0.78 for doses of TNF-a and r = 0.93 for doses of okadiac acid, P <0.005 for each), with associated decreases in cell layer protein (P <0.05 for each) and concomitant increases in the release of sALP activity (e.g., r = 0.89 for TNF-a and r = 0.75 for okadiac acid, P <0.001 for each). In contrast, caspase and calpain inhibitors reduced apoptosis, increased cell layer protein, and decreased the release of sALP activity (P <0.05 for each). Exposure to IGF-I also decreased apoptosis, in a time- and dose-dependent manner (e.g., r = 0.93, P <0.001 for IGF-I doses), with associated proportional effects to increase cell layer protein (P <0.001) and decrease the release of sALP activity (P <0.001). IGF-I also inhibited the actions of TNF-a and okadiac acid to increase apoptosis and sALP release. The associations between apoptosis and sALP release were not unique to osteosarcoma (i.e., SaOS-2) cells, but also seen with osteoblast-line cells derived from normal human bone. Together, these data demonstrate that the release of sALP activity from human osteoblast-line cells in vitro is associated with, and may be a consequence of, apoptotic cell death. These findings are consistent with the general hypothesis that the appearance of sALP activity in serum may reflect the turnover of osteoblast-line cells.

Summary of combined treatment under endoscope on 70 esophagus cancer inpatients

NASA Astrophysics Data System (ADS)

Wang, Cheng; Nong, Meilong; Li, Laisheng; Jia, Fang; Hao, Runchun

1993-03-01

We announce with satisfaction that combined treatment on 70 inpatients who suffered esophageal cancer in its middle or late course is perfectly successful. The combined methods include phototherapy, microwave therapy, and anticarcinogen local injection. The results are as follows: CR 3 cases, holds 4.3% of the total inpatients; PR 36 cases, 51.4%; MR 24 cases, 34.3%; NR 7 cases, 10%; the total effective rate 90%. Splendid results of treatment on enlarging the canal, improving dysphagia, and releasing obstruction have been obtained. The dysphagic grade increased from 66 to 148, the grade of esophagostenosis from 64 to 147, and the obstruction releasing rate is 69 out of 70 (that is 98.6%). The histological observation after treatment shows that 59/62 inpatients being reported as having cancer cells appear to have retrogression accompanied with a few or large quantities of necrotic cancer cells, and 3 inpatients were changed to negative reaction. No obvious poisoning or side effects arose. The combined treatment is more advantageous on those of old age or the physically weak and those who cannot stand for an operation, radiotherapy, or normal chemotherapy.

Formulation and evaluation of polyelectrolyte complex-based matrix tablet of Isosorbide Mononitrate

PubMed Central

Syed, Iizhar Ahmed; Niveditha, P.; Ahmad, Ismail

2014-01-01

Introduction: The polyelectrolyte Complexes (PECs) are based on ionic cross-linking. They have been employed to prepare a sustained release matrix tablets. These systems are based upon the fact that their structure can entrap the drug within them. Isosorbide Mononitrate (ISMN) is an anti-anginal organic nitrate vasodilator used in the treatment of various cardiovascular disorders and prophylaxis of angina Pectoris, which is poorly absorbed from the upper GIT, hence CR formulation is desirable. Materials and Methods: Chitosan (CH)/Sodium alginate (SA), Guar gum (GG), and Xanthan gum (XG) were used as PECs, and were prepared using different proportions i.e., in 1:1 and 1:2 ratio. The optimum ratio of CH: SA, CH: GG and CH: XG was in the ratio was 1:2; these are formed due to electrostatic interaction between oppositely charged poly ions. These normally employ a hydrophilic matrix system. Matrix tablet of ISMN was formulated by using PECs as matrix forming agent by wet granulation technique. Results: The tablets were evaluated for hardness, wt variation, drug content, and in-vitro dissolution studies and found to be within limits. Release kinetics data indicated that ISMN released from the PECs-based matrix tablets of CH-SA, CH-GG and CH-XG CP in 1:1 and 1:2 ratio, followed Fickian and non-Fickian diffusion mechanism respectively. Thus, the drug release rate was extended for over a period of more than 12 h stability studies. There is no significant difference in the mean % drug released from formulation CH-X2 after storing for 3 months at 40°C/75% RH. The FT-IR spectra revealed that there was no interaction between polymers and drug, Statistical analysis showed a significant differences (P < 0.05) for the amount of ISMN released from the formulations (MXG) and formulations (CH-X2). Conclusion: Formulation CH-XG2 (1:2) showed better sustained release of highly water-soluble ISMN with the desired release rate. Thus, the formulated PECs-based matrix tablets seems to be a potential candidate for sustained drug delivery of highly soluble drug ISMN in the symptomatic therapy of angina pectoris. PMID:24678461

Masking Release in Children and Adults With Hearing Loss When Using Amplification

PubMed Central

McCreery, Ryan; Kopun, Judy; Lewis, Dawna; Alexander, Joshua; Stelmachowicz, Patricia

2016-01-01

Purpose This study compared masking release for adults and children with normal hearing and hearing loss. For the participants with hearing loss, masking release using simulated hearing aid amplification with 2 different compression speeds (slow, fast) was compared. Method Sentence recognition in unmodulated noise was compared with recognition in modulated noise (masking release). Recognition was measured for participants with hearing loss using individualized amplification via the hearing-aid simulator. Results Adults with hearing loss showed greater masking release than the children with hearing loss. Average masking release was small (1 dB) and did not depend on hearing status. Masking release was comparable for slow and fast compression. Conclusions The use of amplification in this study contrasts with previous studies that did not use amplification. The results suggest that when differences in audibility are reduced, participants with hearing loss may be able to take advantage of dips in the noise levels, similar to participants with normal hearing. Although children required a more favorable signal-to-noise ratio than adults for both unmodulated and modulated noise, masking release was not statistically different. However, the ability to detect a difference may have been limited by the small amount of masking release observed. PMID:26540194

Reliability analysis of structural ceramics subjected to biaxial flexure

NASA Technical Reports Server (NTRS)

Chao, Luen-Yuan; Shetty, Dinesh K.

1991-01-01

The reliability of alumina disks subjected to biaxial flexure is predicted on the basis of statistical fracture theory using a critical strain energy release rate fracture criterion. Results on a sintered silicon nitride are consistent with reliability predictions based on pore-initiated penny-shaped cracks with preferred orientation normal to the maximum principal stress. Assumptions with regard to flaw types and their orientations in each ceramic can be justified by fractography. It is shown that there are no universal guidelines for selecting fracture criteria or assuming flaw orientations in reliability analyses.

Mixed-Mode Slip Behavior of the Altotiberina Low-Angle Normal Fault System (Northern Apennines, Italy) through High-Resolution Earthquake Locations and Repeating Events

NASA Astrophysics Data System (ADS)

Valoroso, Luisa; Chiaraluce, Lauro; Di Stefano, Raffaele; Monachesi, Giancarlo

2017-12-01

We generated a 4.5-year-long (2010-2014) high-resolution earthquake catalogue, composed of 37,000 events with ML < 3.9 and MC = 0.5 completeness magnitude, to report on the seismic activity of the Altotiberina (ATF) low-angle normal fault system and to shed light on the mechanical behavior and seismic potential of this fault, which is capable of generating a M7 event. Seismicity defines the geometry of the fault system composed of the low-angle (15°-20°) ATF, extending for 50 km along strike and between 4 and 16 km at depth showing an 1.5 km thick fault zone made of multiple subparallel slipping planes, and a complex network of synthetic/antithetic higher-angle segments located in the ATF hanging wall (HW) that can be traced along strike for up to 35 km. Ninety percent of the recorded seismicity occurs along the high-angle HW faults during a series of minor, sometimes long-lasting (months) seismic sequences with multiple MW3+ mainshocks. Remaining earthquakes (ML < 2.4) are released instead along the low-angle ATF at a constant rate of 2.2 events per day. Within the ATF-related seismicity, we found 97 clusters of repeating earthquakes (RE), mostly consisting of doublets occurring during short interevent time (hours). RE are located within the geodetically recognized creeping portions of the ATF, around the main locked asperity. The rate of occurrence of RE seems quite synchronous with the ATF-HW seismic release, suggesting that creeping may guide the strain partitioning in the ATF system. The seismic moment released by the ATF seismicity accounts for 30% of the geodetic one, implying aseismic deformation. The ATF-seismicity pattern is thus consistent with a mixed-mode (seismic and aseismic) slip behavior.

Correlation of rates of tritium migration through porous concrete

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fukada, S.; Katayama, K.; Takeishi, T.

In a nuclear facility when tritium leaks from a glovebox to room accidentally, an atmosphere detritiation system (ADS) starts operating, and HTO released is recovered by ADS. ADS starts when tritium activity in air becomes higher than its controlled level. Before ADS operates, the laboratory walls are the final enclosure facing tritium and are usually made of porous concrete coated with a hydrophobic paint. In the present study, previous data on the diffusivity and adsorption coefficient of concrete and paints are reviewed. Tritium penetrates and migrates into concrete by following 3 ways. First, gaseous HT or T{sub 2} easily penetratesmore » into porous concrete. Its diffusivity is almost equal to that of H{sub 2}. When a gaseous molecule diffuses through pores with a smaller diameter than a mean free path, its migration rate is described by the Knudsen diffusion formula. The second mechanism is H{sub 2}O vapor diffusion in pores. Concrete holds a lot of structural water. Therefore, H{sub 2}O or HTO vapor can diffuse inside concrete pores along with adsorption-desorption and isotopic exchange with structural water, which is the third mechanism. Literature shows that the diffusivity of HTO through the epoxy-resin paint is determined as D(HTO)=1.0*10{sup -16} m{sup 2}/s. We have used this data to set a model and we have applied it to estimate residual tritium in laboratory walls. We have considered 2 accidental cases and a normal case: first, ADS starts operating 1 hour after 100 Ci HTO is released in the room, secondly, ADS starts 24 hours after 100 Ci HTO release and thirdly, when the walls are exposed to HTO for 10 years of normal operation. It appears that the immediate start up of ADS is indispensable for safety.« less

Atmospheric Propagation Modeling Indicates Homing Pigeons use Loft-Specific Infrasonic 'Map' Cues

NASA Astrophysics Data System (ADS)

Hagstrum, J. T.; Baker, L. M.; Spritzer, J. M.; McKenna, M. H.

2011-12-01

Pigeons (Columba livia) released at distant sites commonly depart in directions significantly off the actual homeward bearing. Such site-dependent deviations, or biases, for birds from a given loft are generally stable over time, but can also change from hour to hour, day to day, and year to year. At some release sites, birds consistently vanish in random directions and have longer flight times and lower return rates. Release sites characterized by frequent disorientation are not uncommon for pigeon lofts in both Europe and the USA. One such site is the Jersey Hill fire tower in upstate New York located ~120 km W of the Cornell loft in Ithaca. Cornell birds released at Jersey Hill between 1968 and 1987 almost always vanished randomly, although birds from other lofts had little difficulty orienting there. The results for one day, however, stand out: on August 13, 1969, Cornell birds released at Jersey Hill vanished consistently to the NE (r = 0.921; n=7) and returned home after normal flight times. Cornell pigeons released the next day again showed 'normal' behavior for the site and departed randomly. If, in fact, the birds are using acoustic cues to navigate, the long-term acoustic 'dead' zone we propose for Jersey Hill, due to prevailing atmospheric conditions, indicates that the cues are coming from a single, relatively restricted area, most likely surrounding the home loft. We have modeled the transmission of infrasonic waves, presumably coupled to the atmosphere from ocean-generated microseisms (0.14 Hz), between the Cornell loft and a number of release sites using HARPA (Hamiltonian Acoustic Ray-tracing Program for the Atmosphere) and rawinsonde data collected near Albany and Buffalo, NY. The HARPA modeling shows that acoustic signals from the Cornell loft reached Jersey Hill only on a few release days with unusual atmospheric conditions, including August 13, and were launched at angles less than ~2° above horizontal, most likely from steep-sided terrain in the loft vicinity. Such low angles would require sound waves to be diffracted around intervening topography, and likely explains why birds released on August 13 vanished from Jersey Hill at a mean direction to the NE (33°) and not closer to the homeward bearing (85°). Cornell birds released at many sites have departure bearings consistent with such topographic effects. At the Dryden III release site just 13 km E of the Cornell loft, pigeons generally departed to the NW (321°, n=630), ~60° off the homeward bearing (258°). Apparently, infrasonic signals from the home loft area were being diffracted around higher terrain between the loft and release site.

Evaluation of Delamination Growth Characterization Methods Under Mode I Fatigue Loading

NASA Technical Reports Server (NTRS)

Murri, Gretchen B.

2012-01-01

Reliable delamination characterization data for laminated composites are needed for input to analytical models of structures to predict delamination. The double-cantilevered beam (DCB) specimen is used with laminated composites to measure fracture toughness, G(sub Ic), delamination onset strain energy release rate, and growth rate data under cyclic loading. In the current study, DCB specimens of IM7/8552 graphite/epoxy supplied by two different manufacturers were tested in static and fatigue to compare the measured characterization data from the two sources, and to evaluate a proposed ASTM standard for generating Paris Law equations. Static results were used to generate compliance calibration constants for the fatigue data, and a delamination resistance curve, G(sub IR), which was used to determine the effects of fiber-bridging on delamination growth. Specimens were tested in fatigue at a cyclic G(sub Imax) level equal to 50, 40 or 30% of G(sub Ic), to determine a delamination onset curve and delamination growth rate. The delamination onset curve equations had similar exponents and the same trends. Delamination growth rate was calculated by fitting a Paris Law to the da/dN versus G(sub Imax) data. Both a 2-point and a 7-point data reduction method were used and the Paris Law equations were compared. To determine the effects of fiber-bridging, growth rate results were normalized by the delamination resistance curve for each material and compared to the non-normalized results. Paris Law exponents were found to decrease by 31% to 37% due to normalizing the growth data. Normalizing the data also greatly reduced the amount of scatter between the different specimens. Visual data records from the fatigue testing were used to calculate individual compliance calibration constants from the fatigue data for some of the specimens. The resulting da/dN versus G(sub Imax) plots showed much improved repeatability between specimens. Gretchen

Dopamine Release and Uptake Impairments and Behavioral Alterations Observed in Mice that Model Fragile X Mental Retardation Syndrome.

PubMed

Fulks, Jenny L; O'Bryhim, Bliss E; Wenzel, Sara K; Fowler, Stephen C; Vorontsova, Elena; Pinkston, Jonathan W; Ortiz, Andrea N; Johnson, Michael A

2010-10-20

In this study we evaluated the relationship between amphetamine-induced behavioral alterations and dopamine release and uptake characteristics in Fmr1 knockout (Fmr1 KO) mice, which model fragile X syndrome. The behavioral analyses, obtained at millisecond temporal resolution and 2 mm spatial resolution using a force-plate actometer, revealed that Fmr1 KO mice express a lower degree of focused stereotypy compared to wild type (WT) control mice after injection with 10 mg/kg (ip) amphetamine. To identify potentially related neurochemical mechanisms underlying this phenomenon, we measured electrically-evoked dopamine release and uptake using fast-scan cyclic voltammetry at carbon-fiber microelectrodes in striatal brain slices. At 10 weeks of age, dopamine release per pulse, which is dopamine release corrected for differences in uptake, was unchanged. However, at 15 (the age of behavioral testing) and 20 weeks of age, dopamine per pulse and the maximum rate of dopamine uptake was diminished in Fmr1 KO mice compared to WT mice. Dopamine uptake measurements, obtained at different amphetamine concentrations, indicated that dopamine transporters in both genotypes have equal affinities for amphetamine. Moreover, dopamine release measurements from slices treated with quinpirole, a D2-family receptor agonist, rule out enhanced D2 autoreceptor sensitivity as a mechanism of release inhibition. However, dopamine release, uncorrected for uptake and normalized against the corresponding pre-drug release peaks, increased in Fmr1 KO mice, but not in WT mice. Collectively, these data are consistent with a scenario in which a decrease in extracellular dopamine levels in the striatum result in diminished expression of focused stereotypy in Fmr1 KO mice.

Release of chemical permeation enhancers from drug-in-adhesive transdermal patches.

PubMed

Qvist, Michael H; Hoeck, Ulla; Kreilgaard, Bo; Madsen, Flemming; Frokjaer, Sven

2002-01-14

There is only limited knowledge of how chemical permeation enhancers release from transdermal drug delivery systems of the drug-in-adhesive type. In this study, the release of eight commonly known enhancers from eight types of polymer adhesives was evaluated using Franz diffusion cells. It was shown that all the enhancers released completely from the adhesives and followed a square root of time kinetic (Higuchi law). Using a statistical analysis it was shown that the release rate was more dependent on the type of enhancer than on the type of polymers. The mean release rates were in the range from 2.2 to 11.1%/ radical t for the slowest and fastest releasing enhancers, which correspond to a 50% release within 500 and 20 min, respectively. Furthermore, the release rates were inversely proportional to the cube root of the molal volumes of the enhancers and to their logarithmic partition coefficients between the polymer adhesive and the receptor fluid. It was found that the observed release rates were probably due to a high diffusion coefficient of the enhancers rather than due to an inhomogeneous embedment of the enhancers in the adhesives. The type of adhesive showed minor influence on the release rate, especially among the acrylic polymers no difference was seen. However, compared to the acrylic adhesives, the polyisobutylene adhesive showed slower release rates, while the silicone adhesive showed slightly faster release rates.

Hyperthyroidism and acromegaly due to a thyrotropin- and growth hormone-secreting pituitary tumor. Lack of hormonal response to bromocriptine.

PubMed

Carlson, H E; Linfoot, J A; Braunstein, G D; Kovacs, K; Young, R T

1983-05-01

A 47-year-old woman with acromegaly and hyperthyroidism was found to have an inappropriately normal serum thyrotropin level (1.5 to 2.5 microU/ml) that responded poorly to thyrotropin-releasing hormone but showed partial responsiveness to changes in circulating thyroid hormones. Serum alpha-subunit levels were high-normal and showed a normal response to thyrotropin-releasing hormone. Growth hormone and thyrotropin hypersecretion persisted despite radiotherapy and bromocriptine treatment. Selective trans-sphenoidal removal of a pituitary adenoma led to normalization of both growth hormone and thyrotropin levels. Both thyrotropes and somatotropes were demonstrated in the adenoma by the immunoperoxidase technique and electron microscopy.

Effects of solubilizing surfactants and loading of antiviral, antimicrobial, and antifungal drugs on their release rates from ethylene vinyl acetate copolymer

PubMed Central

Tallury, Padmavathy; Randall, Marcus K; Thaw, Khin L; Preisser, John S.; Kalachandra, Sid

2013-01-01

Objectives This study investigates the effects of surfactants and drug loading on the drug release rate from ethylene vinyl acetate (EVA) copolymer. The release rate of nystatin from EVA was studied with addition of non-ionic surfactants Tween 60 and Cremophor RH 40. In addition, the effect of increasing drug load on the release rates of nystatin, chlorhexidine diacetate and acyclovir is also presented. Method Polymer casting solutions were prepared by stirring EVA copolymer and nystatin (2.5 wt %) in dichloromethane. Nystatin and surfactants were added in ratios of (1:1), (1:2) and (1:3). Drug loading was studied with 2.5, 5.0, 7.5, and 10.0% wt. proportions of nystatin, chlorhexidine diacetate and acyclovir incorporated into a separate polymer. Three drug loaded polymer square films (3cm × 3cm × 0.08 cm) were cut from dry films to follow the kinetics of drug release at 37°C. 10 ml of either distilled water or PBS was used as the extracting medium that was replaced daily. PBS was used for nystatin release with addition of surfactants and water was used for the study on drug loading and surfactant release. The rate of drug release was measured by UV-spectrophotometer. The amount of surfactant released was determined by HPLC. Results The release of nystatin was low in PBS and its release rate increased with the addition of surfactants. Also, increasing surfactant concentrations resulted in increased drug release rates. The release rates of chlorhexidine diacetate (p<0.0001), acyclovir (p<0.0003) and nystatin (p<0.0017) linearly increased with increasing drug loads. The amount of surfactants released was above the CMC. Significance This study demonstrates that the three therapeutic agents show a sustained rate of drug release from EVA copolymer over extended periods of time. Nystatin release in PBS is low owing to its poor solubility. Its release rate is enhanced by addition of surfactants and increasing the drug load as well. PMID:17049593

Controlled-release tablet formulation of isoniazid.

PubMed

Jain, N K; Kulkarni, K; Talwar, N

1992-04-01

Guar (GG) and Karaya gums (KG) alone and in combination with hydroxy-propylmethylcellulose (HPMC) were evaluated as release retarding materials to formulate a controlled-release tablet dosage form of isoniazid (1). In vitro release of 1 from tablets followed non-Fickian release profile with rapid initial release. Urinary excretion studies in normal subjects showed steady-state levels of 1 for 13 h. In vitro and in vivo data correlated (r = 0.9794). The studies suggested the potentiality of GG and KG as release retarding materials in formulating controlled-release tablet dosage forms of 1.

In situ release rates of Cu and Zn from commercial antifouling paints at different salinities.

PubMed

Lagerström, Maria; Lindgren, J Fredrik; Holmqvist, Albin; Dahlström, Mia; Ytreberg, Erik

2018-02-01

Antifouling paints are environmentally risk assessed based on their biocidal release rates to the water phase. In situ release rates of copper (Cu) and zinc (Zn) were derived for five commercial paints in two recreational marinas with different salinities (5 and 14 PSU) using an X-Ray Fluorescence spectrometer (XRF). Salinity was found to significantly affect the Cu release, with twice the amount of Cu released at the higher salinity, while its influence on the Zn release was paint-specific. Site-specific release rates for water bodies with salinity gradients, e.g. the Baltic Sea, are therefore necessary for more realistic risk assessments of antifouling paints. Furthermore, the in situ release rates were up to 8 times higher than those generated using standardized laboratory or calculation methods. The environmental risk assessment repeated with the field release rates concludes that it is questionable whether the studied products should be allowed on the Swedish market. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Outcomes of percutaneous trigger finger release with concurrent steroid injection.

PubMed

Liu, Wen-Chih; Lu, Chun-Kuan; Lin, Yu-Chuan; Huang, Peng-Ju; Lin, Gau-Tyan; Fu, Yin-Chih

2016-12-01

Percutaneous release (PR) of the A1 pulley is a quick, safe, and minimally invasive procedure for treating trigger fingers. The purpose of this study is to identify if PR with additional steroid injections can shorten the recovery to reach unlimited range of motion. Between January 2013 and December 2013, we included 432 trigger fingers with actively correctable triggering or severer symptoms without previous surgical release or steroid injections from two hand clinic offices (A and B). The same experienced surgeon performed PR at the office. Patients from Clinic A received PR with steroid injections and those from Clinic B received PR without steroid injections. Patients returned for follow-up 1 week, 6 weeks, and 12 weeks after the procedure. Between the steroid group and the nonsteroid group, there is no significant difference in the mean time for patients to return to normal work and the rate of residual extensor lag. Middle fingers showed a 5.09-fold chance of having a residual extensor lag over that of the other fingers. High grade trigger fingers recovered more slowly than low grade ones. The success rate of a 12-week follow-up was 98.4%. There was no significant difference between the steroid group (97.5%) and the nonsteroid group (99.1%). PR can treat trigger fingers effectively, but additional steroid injection does not provide more benefit. Some fingers showed temporary extensor lag, especially in middle fingers and high grade trigger fingers, but 85% of those will eventually reach full recovery after self-rehabilitation without another surgical release. Copyright © 2016. Published by Elsevier Taiwan.

Swelling, erosion and drug release characteristics of salbutamol sulfate from hydroxypropyl methylcellulose-based matrix tablets.

PubMed

Chaibva, Faith A; Khamanga, Sandile M M; Walker, Roderick B

2010-12-01

Hydrophilic matrix formulations are important and simple technologies that are used to manufacture sustained release dosage forms. Hydroxypropyl methylcellulose-based matrix tablets, with and without additives, were manufactured to investigate the rate of hydration, rate of erosion, and rate and mechanism of drug release. Scanning electron microscopy was used to assess changes in the microstructure of the tablets during drug release testing and whether these changes could be related to the rate of drug release from the formulations. The results revealed that the rate of hydration and erosion was dependent on the polymer combination(s) used, which in turn affected the rate and mechanism of drug release from these formulations. It was also apparent that changes in the microstructure of matrix tablets could be related to the different rates of drug release that were observed from the test formulations. The use of scanning electron microscopy provides useful information to further understand drug release mechanisms from matrix tablets.

Geometric and thermal controls on normal fault seismicity from rate-and-state friction models

NASA Astrophysics Data System (ADS)

Mark, H. F.; Behn, M. D.; Olive, J. A. L.; Liu, Y.

2017-12-01

Seismic and geodetic observations from the last two decades have led to a growing realization that a significant amount of fault slip at plate boundaries occurs aseismically, and that the amount of aseismic displacement varies across settings. Here we investigate controls on the seismogenic behavior of crustal-scale normal faults that accommodate extensional strain at mid-ocean ridges and continental rifts. Seismic moment release rates measured along the fast-spreading East Pacific Rise suggest that the majority of fault growth occurs aseismically with almost no seismic slip. In contrast, at the slow-spreading Mid-Atlantic Ridge seismic slip may represent up to 60% of the total fault displacement. Potential explanations for these variations include heterogeneous distributions of frictional properties on fault surfaces, effects of variable magma supply associated with seafloor spreading, and/or differences in fault geometry and thermal structure. In this study, we use rate-and-state friction models to study the seismic coupling coefficient (the fraction of total fault slip that occurs seismically) for normal faults at divergent plate boundaries, and investigate controls on fault behavior that might produce the variations in the coupling coefficient observed in natural systems. We find that the seismic coupling coefficient scales with W/h*, where W is the downdip width of the seismogenic area of the fault and h* is the critical earthquake nucleation size. At mid-ocean ridges, W is expected to increase with decreasing spreading rate. Thus, the observed relationship between seismic coupling and W/h* explains to first order variations in seismic coupling coefficient as a function of spreading rate. Finally, we use catalog data from the Gulf of Corinth to show that this scaling relationship can be extended into the thicker lithosphere of continental rift systems.

Monomeric adiponectin modulates nitric oxide release and calcium movements in porcine aortic endothelial cells in normal/high glucose conditions.

PubMed

Grossini, Elena; Farruggio, Serena; Qoqaiche, Fatima; Raina, Giulia; Camillo, Lara; Sigaudo, Lorenzo; Mary, David; Surico, Nicola; Surico, Daniela

2016-09-15

Perivascular adipose tissue can be involved in the process of cardiovascular pathology through the release of adipokines, namely adiponectins. Monomeric adiponectin has been shown to increase coronary blood flow in anesthetized pigs through increased nitric oxide (NO) release and the involvement of adiponectin receptor 1 (AdipoR1). The present study was therefore planned to examine the effects of monomeric adiponectin on NO release and Ca(2+) transients in porcine aortic endothelial cells (PAEs) in normal/high glucose conditions and the related mechanisms. PAEs were treated with monomeric adiponectin alone or in the presence of intracellular kinases blocker, AdipoR1 and Ca(2+)-ATPase pump inhibitors. The role of Na(+)/Ca(2+) exchanger was examined in experiments performed in zero Na(+) medium. NO release and intracellular Ca(2+) were measured through specific probes. In PAE cultured in normal glucose conditions, monomeric adiponectin elevated NO production and [Ca(2+)]c. Similar effects were observed in high glucose conditions, although the response was lower and not transient. The Ca(2+) mobilized by monomeric adiponectin originated from an intracellular pool thapsigargin- and ATP-sensitive and from the extracellular space. Moreover, the effects of monomeric adiponectin were prevented by kinase blockers and AdipoR1 inhibitor. Finally, in normal glucose condition, a role for Na(+)/Ca(2+) exchanger and Ca(2+)-ATPase pump in restoring Ca(2+) was found. Our results add new information about the control of endothelial function elicited by monomeric adiponectin, which would be achieved by modulation of NO release and Ca(2+) transients. A signalling related to Akt, ERK1/2 and p38MAPK downstream AdipoR1 would be involved. Copyright © 2016 Elsevier Inc. All rights reserved.

Synthesis and colon-specific drug delivery of a poly(acrylic acid-co-acrylamide)/MBA nanosized hydrogel.

PubMed

Ray, Debajyoti; Mohapatra, Dillip K; Mohapatra, Ranjit K; Mohanta, Guru P; Sahoo, Prafulla K

2008-01-01

Intravenous administration of 5-fluorouracil (5-FU) for colon cancer therapy produces severe systemic side-effects due to its cytotoxic effect on normal cells. The main objective of the present study was to develop novel oral site-specific delivery of 5-FU to the colon with less drug being released in the stomach or small intestine using biodegradable hydrogel, hydrogel nanoparticles and comparing the targeting efficiency of 5-FU to colon from both. Poly(acrylic acid-co-acrylamide) (P(AA-co-Am)) normal hydrogel and hydrogel nanoparticles (HN) were synthesized by free radical polymerization using N,N-methylene-bis-acrylamide (MBA) as cross-linker, potassium persulfate as reaction initiator and 5-FU was loaded. HN were found to be degradable in physiological medium and showed comparatively higher swelling in rat caecal medium (RCM). 5-FU entrapment was increased by increasing Am (wt%) monomer feed. In vitro release of 5-FU from normal hydrogel and HN in pH progressive medium, it was found that a AA/Am ratio of 25:75 showed higher release in RCM. The Higuchi model yielded good adjustment of in vitro release kinetics. A higher amount of 5-FU reached the colon in HN (61 +/- 2.1%) than normal hydrogel (40 +/- 3.6%) by organ biodistribution studies in albino rats.

Hyperoxic preconditioning fails to confer additional protection against ischemia-reperfusion injury in acute diabetic rat heart.

PubMed

Pourkhalili, Khalil; Hajizadeh, Sohrab; Akbari, Zahra; Dehaj, Mansour Esmaili; Akbarzadeh, Samad; Alizadeh, Alimohammad

2012-01-01

Experimental studies show that detrimental effects of ischemia-reperfusion (I/R) injury can be attenuated by hyperoxic preconditioning in normal hearts, however, there are few studies about hyperoxia effects in diseased myocardium. The present study was designed to assess the cardioprotective effects of hyperoxia pretreatment (≥ 95 % O2) in acute diabetic rat hearts. Normal and one week acute diabetic rats were either exposed to 60 (H60) and 180 (H180) min of hyperoxia or exposed to normal atmospheric air (21 % O2). Then hearts were isolated immediately and subjected to 30 min of regional ischemia followed by 120 min of reperfusion. Infarct size, cardiomyocyte apoptosis, enzymes release and ischemia induced arrhythmias were determined. Heart of diabetic control rats had less infarct size and decreased LDH and CK-MB release compared to normal hearts. 60 and 180 min of hyperoxia reduced myocardial infarct size and enzymes release in normal hearts. 180 min of hyperoxia also decreased cardiomyocytes apoptosis in normal state. On the other hand, protective values of hyperoxia were not significantly different in diabetic hearts. Moreover, hyperoxia reduced severity of ventricular arrhythmias in normal rat hearts whereas; it did not confer any additional antiarrhythmic protection in diabetic hearts. These findings suggest that diabetic hearts are less susceptible to ischemia-induced arrhythmias and infarction. Hyperoxia greatly protects rat hearts against I/R injury in normal hearts, however, it could not provide added cardioprotective effects in acute phase of diabetes.

Speech-induced striatal dopamine release is left lateralized and coupled to functional striatal circuits in healthy humans: A combined PET, fMRI and DTI study

PubMed Central

Simonyan, Kristina; Herscovitch, Peter; Horwitz, Barry

2013-01-01

Considerable progress has been recently made in understanding the brain mechanisms underlying speech and language control. However, the neurochemical underpinnings of normal speech production remain largely unknown. We investigated the extent of striatal endogenous dopamine release and its influences on the organization of functional striatal speech networks during production of meaningful English sentences using a combination of positron emission tomography (PET) with the dopamine D2/D3 receptor radioligand [11C]raclopride and functional MRI (fMRI). In addition, we used diffusion tensor tractography (DTI) to examine the extent of dopaminergic modulatory influences on striatal structural network organization. We found that, during sentence production, endogenous dopamine was released in the ventromedial portion of the dorsal striatum, in its both associative and sensorimotor functional divisions. In the associative striatum, speech-induced dopamine release established a significant relationship with neural activity and influenced the left-hemispheric lateralization of striatal functional networks. In contrast, there were no significant effects of endogenous dopamine release on the lateralization of striatal structural networks. Our data provide the first evidence for endogenous dopamine release in the dorsal striatum during normal speaking and point to the possible mechanisms behind the modulatory influences of dopamine on the organization of functional brain circuits controlling normal human speech. PMID:23277111

Effect of temperature on endplate potential rundown and recovery in rat diaphragm.

PubMed

Moyer, M; van Lunteren, E

2001-05-01

The amplitude of neuromuscular junction end-plate potentials (EPPs) decreases quickly within a train but recovers nearly completely from train to train during intermittent stimulation. Rundown has been shown to be dependent not only on the rate of transmitter release but also on the rate of replenishment of the depleted neurotransmitter at the site of release. Two groups of processes have been proposed for synaptic vesicle recycling, both of which involve multiple energy-requiring steps and enzymatic reactions and which therefore would be expected to be very temperature-sensitive. The present study tested the hypothesis that low temperature therefore increases the rate of EPP amplitude rundown. Studies were performed in vitro on rat diaphragm and used micro-conotoxin to allow normal-sized EPPs to be recorded from intact fibers. EPP amplitude rundown during intermittent stimulation at 20 and 50 Hz (duty cycle 333 ms) was greater at 20 degrees C than it was at 37 degrees C. Initially, temperature affected only intra-train rundown but, over longer periods of stimulation, both intra- and inter-train rundown were significantly accelerated by cold temperature. Cumulative EPP amplitudes were calculated by successively adding the amplitudes of each EPP during the stimulation period to provide an estimate of total neurotransmitter release in the neuromuscular junction. The cumulative EPP amplitude was significantly lower at 20 degrees C than it was at 37 degrees C during both 20 and 50 Hz stimulation. These data indicate that the mechanism involved in EPP amplitude rundown and recovery is temperature-sensitive, with a greater decrement in EPP amplitude at cold than at warm temperatures.

Potential Application of Silica Mineral from Dieng Mountain in Agriculture Sector to Control the Release Rate of Fertilizer Elements

NASA Astrophysics Data System (ADS)

Solihin; Mursito, Anggoro Tri; Dida, Eki N.; Erlangga, Bagus D.; Widodo

2017-07-01

Silica mineral, which comes along with geothermal fluid in Dieng, is a product of erosion, decomposition and dissolution of silicon oxide based mineral, which is followed by precipitation to form silica mineral. This silica cell structure is non crystalline, and it contains 85,60 % silicon oxide, 6.49 volatile elements, and also other oxide elements. Among the direct potential application of this silica is as raw material in slow release fertilizer. Silica in compacted slow release fertilizer is able control the release rate of fertilizer elements. Two type of slow release fertilizer has been made by using silica as the matrix in these slow release fertilizer. The first type is the mixing of ordinary solid fertilizer with Dieng silica, whereas the second one is the mixing of disposal leach water with Dieng silica. The release test shows that both of these modified fertilizers have slow release fertilizer characteristic. The release rate of fertilizer elements (magnesium, potassium, ammonium, and phosphate) can be significantly reduced. The addition of kaolin in the first type of slow release fertilizer makes the release rate of fertilizer elements can be more slowed down. Meanwhile in the second type of slow release fertilizer, the release rate is determined by ratio of silica/hydrogel. The lowest release rate is achieved by sample that has highest ratio of silica/hydrogel.

Intra-renal delivery of mesenchymal stem cells attenuates myocardial injury after reversal of hypertension in porcine renovascular disease.

PubMed

Eirin, Alfonso; Zhu, Xiang-Yang; Ferguson, Christopher M; Riester, Scott M; van Wijnen, Andre J; Lerman, Amir; Lerman, Lilach O

2015-01-19

Percutaneous transluminal renal angioplasty (PTRA) fails to fully improve cardiac injury and dysfunction in patients with renovascular hypertension (RVH). Mesenchymal stem cells (MSCs) restore renal function, but their potential for attenuating cardiac injury after reversal of RVH has not been explored. We hypothesized that replenishment of MSCs during PTRA would improve cardiac function and oxygenation, and decrease myocardial injury in porcine RVH. Pigs were studied after 16 weeks of RVH, RVH treated 4 weeks earlier with PTRA with or without adjunct intra-renal delivery of MSC (10^6 cells), and controls. Cardiac structure, function (fast-computed tomography (CT)), and myocardial oxygenation (Blood-Oxygen-Level-Dependent- magnetic resonance imaging) were assessed in-vivo. Myocardial microvascular density (micro-CT) and myocardial injury were evaluated ex-vivo. Kidney venous and systemic blood levels of inflammatory markers were measured and their renal release calculated. PTRA normalized blood pressure, yet stenotic-kidney glomerular filtration rate, similarly blunted in RVH and RVH + PTRA, normalized only in PTRA + MSC-treated pigs. PTRA attenuated left ventricular remodeling, whereas myocardial oxygenation, subendocardial microvascular density, and diastolic function remained decreased in RVH + PTRA, but normalized in RVH + PTRA-MSC. Circulating isoprostane levels and renal release of inflammatory cytokines increased in RVH and RVH + PTRA, but normalized in RVH + PTRA-MSC, as did myocardial oxidative stress, inflammation, collagen deposition, and fibrosis. Intra-renal MSC delivery during PTRA preserved stenotic-kidney function, reduced systemic oxidative stress and inflammation, and thereby improved cardiac function, oxygenation, and myocardial injury four weeks after revascularization, suggesting a therapeutic potential for adjunctive MSC delivery to preserve cardiac function and structure after reversal of experimental RVH.

Effect of Magnesium Sulfate and Clonidine in Attenuating Hemodynamic Response to Pneumoperitoneum in Laparoscopic Cholecystectomy

PubMed Central

Kamble, Shruthi P.; Bevinaguddaiah, Yatish; Nagaraja, Dinesh Chillkunda; Pujar, Vinayak S.; Anandaswamy, Tejesh C.

2017-01-01

Background: Pneumoperitoneum in laparoscopic procedures is associated with hemodynamic response, due to the release of catecholamines and vasopressin. Magnesium and clonidine have been used to attenuate such hemodynamic responses by inhibiting release of these mediators. We conducted this randomized, double-blinded study to assess which of the two attenuates hemodynamic response better. Materials and Methods: Ninety American Society of Anesthesiologists health status Classes I and II patients posted for elective laparoscopic cholecystectomy were randomized into three groups of thirty patients each. Group C received injection clonidine 1 μg/kg diluted in 10 mL normal saline over 10 min, prior to pneumoperitoneum. Group M received injection magnesium sulfate 50 mg/kg diluted in 10 mL normal saline over 10 min, prior to pneumoperitoneum. Group NS received 10 mL normal saline intravenously over 10 min, prior to pneumoperitoneum. Hemodynamic parameters were recorded before induction (baseline values), at the end of magnesium sulfate/clonidine/saline administration and before pneumoperitoneum (P0), 5 min (P5), 10 min (P10), 20 min (P20), 30 min (P30), and 40 min (P40) after pneumoperitoneum. Results: Systolic blood pressure, diastolic blood pressure (DBP), mean arterial pressure (MAP), and heart rate (HR) were all significantly higher in the normal saline group compared to magnesium and clonidine. On comparing patients in Group M and Group C, DBP, MAP, and HR were significantly lower in the magnesium group. Mean extubation time and time to response to verbal commands were significantly longer in the magnesium group. Conclusions: Both magnesium and clonidine attenuated the hemodynamic response to pneumoperitoneum. However, magnesium 50 mg/kg, attenuated hemodynamic response better than clonidine 1 μg/kg. PMID:28298759

Improved estimates of environmental copper release rates from antifouling products.

PubMed

Finnie, Alistair A

2006-01-01

The US Navy Dome method for measuring copper release rates from antifouling paint in-service on ships' hulls can be considered to be the most reliable indicator of environmental release rates. In this paper, the relationship between the apparent copper release rate and the environmental release rate is established for a number of antifouling coating types using data from a variety of available laboratory, field and calculation methods. Apart from a modified Dome method using panels, all laboratory, field and calculation methods significantly overestimate the environmental release rate of copper from antifouling coatings. The difference is greatest for self-polishing copolymer antifoulings (SPCs) and smallest for certain erodible/ablative antifoulings, where the ASTM/ISO standard and the CEPE calculation method are seen to typically overestimate environmental release rates by factors of about 10 and 4, respectively. Where ASTM/ISO or CEPE copper release rate data are used for environmental risk assessment or regulatory purposes, it is proposed that the release rate values should be divided by a correction factor to enable more reliable generic environmental risk assessments to be made. Using a conservative approach based on a realistic worst case and accounting for experimental uncertainty in the data that are currently available, proposed default correction factors for use with all paint types are 5.4 for the ASTM/ISO method and 2.9 for the CEPE calculation method. Further work is required to expand this data-set and refine the correction factors through correlation of laboratory measured and calculated copper release rates with the direct in situ environmental release rate for different antifouling paints under a range of environmental conditions.

Harvest and reporting rates of game-farm ring-necked pheasants

USGS Publications Warehouse

Diefenbach, D.R.; Riegner, C.F.; Hardisky, T.S.

2000-01-01

Many state natural resource agencies release ring-necked pheasants (Phasianus colchicus) for hunting, but the effectiveness of these programs has never been evaluated on a statewide basis. We conducted a reward-band study to estimate harvest, reporting, and survival rates of pheasants raised and released by the Pennsylvania Game Commission (PGC) for the fall 1998 hunting season. We banded 6,770 of 199,613 released pheasants with leg bands worth $0-$400. Rewards >$75 produced 100% reporting rates. Hunters reported 71.0% of harvested pheasants banded with standard bands (no reward). Cocks had an estimated 62.3% harvest rate when released on public land and a 46.8% harvest rate on private land. Hens had an estimated 50.4% harvest rate when released on public land and a 31.1% harvest rate on private land. Estimated harvest rate for hen pheasants released in September in the either-sex zone was 15.5%. In the late season, pheasants released on public land had a 33.6% harvest rate and a 23.5% harvest rate on private land. We found that few pheasants (30 days and birds released on public land had reduced survival rates primarily because of greater harvest rates. In fiscal year 1998-99, the net cost to raise and release 199,613 pheasants was $2,813,138 ($14.09 per bird). The average cost per harvested pheasant was $29.10, but ranged from $22.63 to $90.74 depending on the date and location of release. We estimated that 49.9% (82,017 birds) of pheasants stocked immediately prior to and during the regular and late seasons (excluding September releases of hens) were harvested by hunters. Percentage of pheasants harvested by hunters could be increased by expanding the either-sex zone in Pennsylvania so that more hens could be legally killed by hunters and by allocating releases to seasons and locations with greater harvest rates. However, before such changes are implemented, we recommend a survey of Pennsylvania pheasant hunters to ascertain their opinions and desires regarding releases of game-farm pheasants.

Anterior lumbar instrumentation improves correction of severe lumbar Lenke C curves in double major idiopathic scoliosis

PubMed Central

Yeon, Howard B.; Weinberg, Jacob; Arlet, Vincent; Ouelett, Jean A.

2007-01-01

Fifteen skeletally immature patients with double major adolescent idiopathic scoliosis with large lumbar curves and notable L4 and L5 coronal plane obliquity were retrospectively studied. Seven patients who underwent anterior release and fusion of the lumbar curve with segmental anterior instrumentation and subsequent posterior instrumentation ending at L3 were compared with eight patients treated with anterior release and fusion without anterior instrumentation followed by posterior instrumentation to L3 or L4. At 4.5 years follow-up (range 2.5–7 years), curve correction, coronal balance and fusion rate were not statistically different between the two groups; however, the group with anterior instrumentation had improved coronal plane, near normalangulation in the distal unfused segment compared with the group without anterior instrumentation. In cases involving severe lumbar curvatures in the context of double major scoliosis, when as a first stage anterior release is chosen, the addition of instrumentation appears to restore normal coronal alignment of the distal unfused lumbar segment, and may in certain cases save a level compared with traditional fusions to L4. PMID:17464517

Fission gas release restrictor for breached fuel rod

DOEpatents

Kadambi, N. Prasad; Tilbrook, Roger W.; Spencer, Daniel R.; Schwallie, Ambrose L.

1986-01-01

In the event of a breach in the cladding of a rod in an operating liquid metal fast breeder reactor, the rapid release of high-pressure gas from the fission gas plenum may result in a gas blanketing of the breached rod and rods adjacent thereto which impairs the heat transfer to the liquid metal coolant. In order to control the release rate of fission gas in the event of a breached rod, the substantial portion of the conventional fission gas plenum is formed as a gas bottle means which includes a gas pervious means in a small portion thereof. During normal reactor operation, as the fission gas pressure gradually increases, the gas pressure interiorly of and exteriorly of the gas bottle means equalizes. In the event of a breach in the cladding, the gas pervious means in the gas bottle means constitutes a sufficient restriction to the rapid flow of gas therethrough that under maximum design pressure differential conditions, the fission gas flow through the breach will not significantly reduce the heat transfer from the affected rod and adjacent rods to the liquid metal heat transfer fluid flowing therebetween.

Numerical prediction of mechanical properties of Pb-Sn solder alloys containing antimony, bismuth and or silver ternary trace elements

NASA Astrophysics Data System (ADS)

Gadag, Shiva P.; Patra, Susant

2000-12-01

Solder joint interconnects are mechanical means of structural support for bridging the various electronic components and providing electrical contacts and a thermal path for heat dissipation. The functionality of the electronic device often relies on the structural integrity of the solder. The dimensional stability of solder joints is numerically predicted based on their mechanical properties. Algorithms to model the kinetics of dissolution and subsequent growth of intermetallic from the complete knowledge of a single history of time-temperature-reflow profile, by considering equivalent isothermal time intervals, have been developed. The information for dissolution is derived during the heating cycle of reflow and for the growth process from cooling curve of reflow profile. A simple and quick analysis tool to derive tensile stress-strain maps as a function of the reflow temperature of solder and strain rate has been developed by numerical program. The tensile properties are used in modeling thermal strain, thermal fatigue and to predict the overall fatigue life of solder joints. The numerical analysis of the tensile properties as affected by their composition and rate of testing, has been compiled in this paper. A numerical model using constitutive equation has been developed to evaluate the interfacial fatigue crack growth rate. The model can assess the effect of cooling rate, which depends on the level of strain energy release rate. Increasing cooling rate from normalizing to water-quenching, enhanced the fatigue resistance to interfacial crack growth by up to 50% at low strain energy release rate. The increased cooling rates enhanced the fatigue crack growth resistance by surface roughening at the interface of solder joint. This paper highlights salient features of process modeling. Interfacial intermetallic microstructure is affected by cooling rate and thereby affects the mechanical properties.

Spatially resolved heat release rate measurements in turbulent premixed flames

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ayoola, B.O.; Kaminski, C.F.; Balachandran, R.

Heat release rate is a fundamental property of great importance for the theoretical and experimental elucidation of unsteady flame behaviors such as combustion noise, combustion instabilities, and pulsed combustion. Investigations of such thermoacoustic interactions require a reliable indicator of heat release rate capable of resolving spatial structures in turbulent flames. Traditionally, heat release rate has been estimated via OH or CH radical chemiluminescence; however, chemiluminescence suffers from being a line-of-sight technique with limited capability for resolving small-scale structures. In this paper, we report spatially resolved two-dimensional measurements of a quantity closely related to heat release rate. The diagnostic technique usesmore » simultaneous OH and CH{sub 2}O planar laser-induced fluorescence (PLIF), and the pixel-by-pixel product of the OH and CH{sub 2}O PLIF signals has previously been shown to correlate well with local heat release rates. Results from this diagnostic technique, which we refer to as heat release rate imaging (HR imaging), are compared with traditional OH chemiluminescence measurements in several flames. Studies were performed in lean premixed ethylene flames stabilized between opposed jets and with a bluff body. Correlations between bulk strain rates and local heat release rates were obtained and the effects of curvature on heat release rate were investigated. The results show that the heat release rate tends to increase with increasing negative curvature for the flames investigated for which Lewis numbers are greater than unity. This correlation becomes more pronounced as the flame gets closer to global extinction.« less

Puberty without gonadotropins. A unique mechanism of sexual development.

PubMed

Wierman, M E; Beardsworth, D E; Mansfield, M J; Badger, T M; Crawford, J D; Crigler, J F; Bode, H H; Loughlin, J S; Kushner, D C; Scully, R E

1985-01-10

Recent evidence suggests that a group of children exists in whom premature sexual maturation occurs in the absence of pubertal levels of gonadotropins; that is, they have gonadotropin-independent precocious puberty. We compared six boys and one girl with this disorder with four boys and five girls with central precocious puberty, in which there is a pubertal pattern of gonadotropin release. The two groups were similar in age of onset, degree of sexual development, growth velocity, and rate of skeletal maturation. A family history of precocity was noted in four of the boys with gonadotropin-independent precocity, and the girl had McCune-Albright syndrome. Children with central precocious puberty demonstrated a pulsatile release of gonadotropins, pubertal responses to luteinizing hormone-releasing hormone, and complete suppression of gonadarche after exposure to an analogue of luteinizing hormone-releasing hormone (LHRHa). In contrast, children with gonadotropin-independent precocity demonstrated an absence of gonadotropin pulsations, variable responses to luteinizing hormone-releasing hormone, lack of suppression of puberty in response to LHRHa, and cyclic steroidogenesis. Tissue from testicular biopsies performed in five of six boys with gonadotropin-independent precocity showed a range from incipient pubertal development of the tubules with proliferation of Leydig cells to the appearance of normal adult testes. We conclude that gonadotropin-independent precocious puberty is a distinct syndrome, of unknown cause, that may be familial and may have been responsible for many previously reported cases of precocious puberty.

Radiative Extinction of Gaseous Spherical Diffusion Flames in Microgravity

NASA Technical Reports Server (NTRS)

Santa, K. J.; Chao, B. H.; Sunderland, P. B.; Urban, D. L.; Stocker, D. P.; Axelbaum, R. L.

2007-01-01

Radiative extinction of spherical diffusion flames was investigated experimentally and numerically. The experiments involved microgravity spherical diffusion flames burning ethylene and propane at 0.98 bar. Both normal (fuel flowing into oxidizer) and inverse (oxidizer flowing into fuel) flames were studied, with nitrogen supplied to either the fuel or the oxygen. Flame conditions were chosen to ensure that the flames extinguished within the 2.2 s of available test time; thus extinction occurred during unsteady flame conditions. Diagnostics included color video and thin-filament pyrometry. The computations, which simulated flow from a porous sphere into a quiescent environment, included detailed chemistry, transport and radiation, and yielded transient results. Radiative extinction was observed experimentally and simulated numerically. Extinction time, peak temperature, and radiative loss fraction were found to be independent of flow rate except at very low flow rates. Radiative heat loss was dominated by the combustion products downstream of the flame and was found to scale with flame surface area, not volume. For large transient flames the heat release rate also scaled with surface area and thus the radiative loss fraction was largely independent of flow rate. Peak temperatures at extinction onset were about 1100 K, which is significantly lower than for kinetic extinction. One observation of this work is that while radiative heat losses can drive transient extinction, this is not because radiative losses are increasing with time (flame size) but rather because the heat release rate is falling off as the temperature drops.

Presence of gonadotropin-releasing hormone and its messenger ribonucleic acid in human ovarian epithelial carcinoma.

PubMed

Ohno, T; Imai, A; Furui, T; Takahashi, K; Tamaya, T

1993-09-01

The purpose of this study was to investigate the expression of gonadotropin-releasing hormone messenger ribonucleic acid and the presence of gonadotropin-releasing hormone in human ovarian carcinoma known to have gonadotropin-releasing hormone binding sites and to be affected by gonadotropin-releasing hormone analog. Human ovarian carcinomas surgically removed and human ovarian carcinoma cell lines were examined. Gonadotropin-releasing hormone was determined by a radioimmunoassay and a bioassay. Gonadotropin-releasing hormone messenger ribonucleic acid was determined by reverse transcription polymerase chain reaction using oligonucleotide primers synthesized according to the published human gonadotropin-releasing hormone sequence. Gonadotropin-releasing hormone was shown to be present in extracts of ovarian mucinous cystadenocarcinoma sample (0.8 +/- 0.12 pg/mg of protein) and ovarian adenocarcinoma cell line SK-OV3 (0.92 +/- 0.17 pg/mg of protein) but not in the normal ovary and placenta. Two of two extract samples from individual cases evoked dose-dependent phosphoinositide breakdown in rat granulosa cells similar to that caused by authentic gonadotropin-releasing hormone. Gonadotropin-releasing hormone messenger ribonucleic acid was detected in two of two mucinous cystadenocarcinoma specimens, one of one serous cystadenocarcinoma, and SK-OV3 cells but not in the dysgerminoma, mucinous cystadenoma, and normal ovary and placenta. The demonstration of gonadotropin-releasing hormone and its messenger ribonucleic acid raises the possibility that gonadotropin-releasing hormone may play an autocrine regulatory role in the growth of ovarian carcinoma.

Fission-gas release from uranium nitride at high fission rate density

NASA Technical Reports Server (NTRS)

Weinstein, M. B.; Kirchgessner, T. A.; Tambling, T. N.

1973-01-01

A sweep gas facility has been used to measure the release rates of radioactive fission gases from small UN specimens irradiated to 8-percent burnup at high fission-rate densities. The measured release rates have been correlated with an equation whose terms correspond to direct recoil release, fission-enhanced diffusion, and atomic diffusion (a function of temperature). Release rates were found to increase linearly with burnups between 1.5 and 8 percent. Pore migration was observed after operation at 1550 K to over 6 percent burnup.

Random and independent sampling of endogenous tryptic peptides from normal human EDTA plasma by liquid chromatography micro electrospray ionization and tandem mass spectrometry.

PubMed

Dufresne, Jaimie; Florentinus-Mefailoski, Angelique; Ajambo, Juliet; Ferwa, Ammara; Bowden, Peter; Marshall, John

2017-01-01

Normal human EDTA plasma samples were collected on ice, processed ice cold, and stored in a freezer at - 80 °C prior to experiments. Plasma test samples from the - 80 °C freezer were thawed on ice or intentionally warmed to room temperature. Protein content was measured by CBBR binding and the release of alcohol soluble amines by the Cd ninhydrin assay. Plasma peptides released over time were collected over C18 for random and independent sampling by liquid chromatography micro electrospray ionization and tandem mass spectrometry (LC-ESI-MS/MS) and correlated with X!TANDEM. Fully tryptic peptides by X!TANDEM returned a similar set of proteins, but was more computationally efficient, than "no enzyme" correlations. Plasma samples maintained on ice, or ice with a cocktail of protease inhibitors, showed lower background amounts of plasma peptides compared to samples incubated at room temperature. Regression analysis indicated that warming plasma to room temperature, versus ice cold, resulted in a ~ twofold increase in the frequency of peptide identification over hours-days of incubation at room temperature. The type I error rate of the protein identification from the X!TANDEM algorithm combined was estimated to be low compared to a null model of computer generated random MS/MS spectra. The peptides of human plasma were identified and quantified with low error rates by random and independent sampling that revealed 1000s of peptides from hundreds of human plasma proteins from endogenous tryptic peptides.

Exercise capacity is associated with endothelin-1 release during emotional excitement in coronary artery disease patients.

PubMed

Tulppo, Mikko P; Piira, Olli-Pekka; Hautala, Arto J; Kiviniemi, Antti M; Miettinen, Johanna A; Huikuri, Heikki V

2014-08-01

Endothelin-1 (ET-1), a potent vasoconstrictor, IL-6, and catecholamines are increased and heart rate variability [SD of normal to normal R-R intervals (SDNN)] decreased during emotional excitement, but individual responses vary. We tested the hypothesis that exercise capacity is associated with physiological responses caused by real-life emotional excitement. We measured the plasma levels of ET-1, IL-6, catecholamines, heart rate, and SDNN in enthusiastic male ice hockey spectators (n = 51; age, 59 ± 9 years) with stable coronary artery disease (CAD) at baseline and during the Finnish National Ice Hockey League's final play-off matches. Maximal exercise capacity (METs) by bicycle exercise test and left ventricular ejection fraction (LVEF) were measured on a separate day. ET-1 response from baseline to emotional excitement correlated with maximal METs (r = -0.30; P = 0.040). In a linear stepwise regression analysis age, body mass index (BMI), METs, LVEF, basal ET-1, and subjective experience of excitement were entered the model as independent variables to explain ET-1 response. This model explained 27% of ET-1 response (P = 0.003). Maximal METs were most strongly correlated with ET-1 response (β = -0.45; partial correlation r = -0.43; P = 0.002), followed by BMI (β = -0.31; partial correlation r = -0.31; P = 0.033) and LVEF (β = -0.30; partial correlation r = -0.33; P = 0.023). Exercise capacity may protect against further cardiovascular events in CAD patients, because it is associated with reduced ET-1 release during emotional excitement. Copyright © 2014 the American Physiological Society.

Effect of Chlorotriazine Pesticides on Gonadotrophin Releasing Hormone in the Neuronal GT1-7 Cell Line and Hypothalamic Explants

EPA Science Inventory

Gonadotrophin releasing hormone (GnRH) stimulates the release of pituitary luteinizing hormone (LH) and follicle stimulating hormone. These pituitary hormones are necessary for normal reproductive function in both males and females. It is well recognized that disruption of nor...

Equivalent Safety Basis for Evaluation of On-Site Packages for US DOE Facilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, A.C.

Packages for transport of radioactive material within the boundaries of a Department of Energy facility (on-site) must conform to the requirements for packages shipped in normal commerce, or must provide equivalent safety. Equivalence is achieved if the frequency of severe on-site accidents, which could result in a release of radioactive material, is less than or equal to the frequency of Beyond-HAC accidents for packages in commerce. This is shown to be achieved it the rate of on-site accident is 22 per 100 MVM or lower. For equivalence to Normal Conditions of Transport, for on-site packages, appropriate, defensible Design Basis Conditionsmore » can be established and the ability of the package to meet the reduced requirements shown in the On-site Safety Assessment.« less

Nisin as a Food Preservative: Part 2: Antimicrobial Polymer Materials Containing Nisin.

PubMed

Gharsallaoui, Adem; Joly, Catherine; Oulahal, Nadia; Degraeve, Pascal

2016-06-10

Nisin is the only bacteriocin approved as a food preservative because of its antibacterial effectiveness and its negligible toxicity for humans. Typical problems encountered when nisin is directly added to foods are mainly fat adsorption leading to activity loss, heterogeneous distribution in the food matrix, inactivation by proteolytic enzymes, and emergence of resistance in normally sensitive bacteria strains. To overcome these problems, nisin can be immobilized in solid matrices that must act as diffusional barriers and allow controlling its release rate. This strategy allows maintaining a just sufficient nisin concentration at the food surface. The design of such antimicrobial materials must consider both bacterial growth kinetics but also nisin release kinetics. In this review, nisin incorporation in polymer-based materials will be discussed and special emphasis will be on the applications and properties of antimicrobial food packaging containing this bacteriocin.

Purity of food cooked in stainless steel utensils.

PubMed

Flint, G N; Packirisamy, S

1997-01-01

An extensive programme of cooking operations, using household recipes, has shown that, apart from aberrant values associated with new pans on first use, the contribution made by 19% Cr/9% Ni stainless steel cooking utensils to chromium and nickel in the diet is negligible. New pans, if first used with acid fruits, showed a greater pick-up of chromium and nickel, ranging from approximately 1/20 to 1/3 and 1/20 to 1/2 of the normal daily intake of chromium and nickel respectively. This situation did not recur in subsequent usage, even after the pan had been cleaned by abrasion. A higher rate of chromium and nickel release in new pans on first use was observed on products from four manufactures and appears to be related to surface finish, since treatment of the surface of a new pan was partly, and in the case of electropolishing, wholly effective in eliminating their initial high release.

Factors influencing immediate post-release survival of spectacled eiders following surgical implantation of transmitters with percutaneous antennae

USGS Publications Warehouse

Sexson, Matthew G.; Mulcahy, Daniel M.; Spriggs, Maria; Myers, Gwen E.

2014-01-01

Surgically implanted transmitters are a common method for tracking animal movements. Immediately following surgical implantation, animals pass through a critical recovery phase when behaviors may deviate from normal and the likelihood of individual survival may be reduced. Therefore, data collected during this period may be censored to minimize bias introduced by surgery-related behaviors or mortality. However, immediate post-release mortalities negate a sampling effort and reduce the amount of data potentially collected after the censoring period. Wildlife biologists should employ methods to support an animal’s survival through this period, but factors contributing to immediate post-release survival have not been formally assessed. We evaluated factors that potentially influenced the immediate post-release survival of 56 spectacled eiders (Somateria fischeri) marked with coelomically implanted satellite transmitters with percutaneous antennae in northern Alaska in 2010 and 2011. We modeled survival through the first 14 days following release and assessed the relative importance and effect of 15 covariates hypothesized to influence survival during this immediate post-release period. Estimated daily survival rate increased over the duration of the immediate post-release period; the probability of mortality was greatest within the first 5 days following release. Our top-ranking model included the effect of 2 blood analytes, pH and hematocrit, measured prior to surgical implantation of a transmitter. We found a positive response to pH; eiders exhibiting acidemia (low pH) prior to surgery were less likely to survive the immediate post-release period. We found a curvilinear response to hematocrit; eiders exhibiting extremely low or high pre-surgery hematocrit were also less likely to survive the immediate post-release period. In the interest of maximizing the survival of marked birds following release, hematological data obtained prior to surgical implantation of telemetry equipment may be useful when screening for optimal surgical candidates or informing appropriate response to mitigate potentially deleterious disorders such as acidemia.

Tribological Analysis of Copper-Coated Graphite Particle-Reinforced A359 Al/5 wt.% SiC Composites

NASA Astrophysics Data System (ADS)

Lin, C. B.; Wang, T. C.; Chang, Z. C.; Chu, H. Y.

2013-01-01

Copper-coated graphite particles can be mass-produced by the cementation process using simple equipment. Graphite particulates that were coated with electroless copper and 5 wt.% SiC particulates were introduced into an aluminum alloy by compocasting to make A359 Al/5 wt.% SiC(p) composite that contained 2, 4, 6, and 8 wt.% graphite particulate composite. The effects of SiC particles, quantity of graphite particles, normal loading, sliding speed and wear debris on the coefficient of friction, and the wear rate were investigated. The results thus obtained indicate that the wear properties were improved by adding small amounts of SiC and graphite particles into the A359 Al alloy. The coefficient of friction of the A359 Al/5 wt.% SiC(p) composite that contained 6.0 wt.% graphite particulates was reduced to 0.246 and the amount of graphite film that was released on the worn surface increased with the graphite particulate content. The coefficient of friction and the wear rate were insensitive to the variation in the sliding speed and normal loading.

Spatial Release From Masking in Simulated Cochlear Implant Users With and Without Access to Low-Frequency Acoustic Hearing

PubMed Central

Dietz, Mathias; Hohmann, Volker; Jürgens, Tim

2015-01-01

For normal-hearing listeners, speech intelligibility improves if speech and noise are spatially separated. While this spatial release from masking has already been quantified in normal-hearing listeners in many studies, it is less clear how spatial release from masking changes in cochlear implant listeners with and without access to low-frequency acoustic hearing. Spatial release from masking depends on differences in access to speech cues due to hearing status and hearing device. To investigate the influence of these factors on speech intelligibility, the present study measured speech reception thresholds in spatially separated speech and noise for 10 different listener types. A vocoder was used to simulate cochlear implant processing and low-frequency filtering was used to simulate residual low-frequency hearing. These forms of processing were combined to simulate cochlear implant listening, listening based on low-frequency residual hearing, and combinations thereof. Simulated cochlear implant users with additional low-frequency acoustic hearing showed better speech intelligibility in noise than simulated cochlear implant users without acoustic hearing and had access to more spatial speech cues (e.g., higher binaural squelch). Cochlear implant listener types showed higher spatial release from masking with bilateral access to low-frequency acoustic hearing than without. A binaural speech intelligibility model with normal binaural processing showed overall good agreement with measured speech reception thresholds, spatial release from masking, and spatial speech cues. This indicates that differences in speech cues available to listener types are sufficient to explain the changes of spatial release from masking across these simulated listener types. PMID:26721918

Metal release from stainless steel particles in vitro-influence of particle size.

PubMed

Midander, K; Pan, J; Wallinder, I Odnevall; Leygraf, C

2007-01-01

Human inhalation of airborne metallic particles is important for health risk assessment. To study interactions between metallic particles and the human body, metal release measurements of stainless steel powder particles were performed in two synthetic biological media simulating lung-like environments. Particle size and media strongly influence the metal release process. The release rate of Fe is enhanced compared with Cr and Ni. In artificial lysosomal fluid (ALF, pH 4.5), the accumulated amounts of released metal per particle loading increase drastically with decreasing particle size. The release rate of Fe per unit surface area increases with decreasing particle size. Compared with massive sheet metal, fine powder particles (<4 microm) show similar release rates of Cr and Ni, but a higher release rate of Fe. Release rates in Gamble's solution (pH 7.4), for all powders investigated, are significantly lower compared to ALF. No clear trend is seen related to particle size in Gamble's solution.

TA [2] Continuous, regional methane emissions estimates in northern Pennsylvania gas fields using atmospheric inversions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lauvaux, Thomas

Natural Gas (NG) production activities in the northeastern Marcellus shale have significantly increased in the last decade, possibly releasing large amounts of methane (CH 4) into the atmosphere from the operations at the productions sites and during the processing and transmission steps of the natural gas chain. Based on an intensive aircraft survey, leakage rates from the NG production were quantified in May 2015 and found to be in the order of 0.5% of the total production, higher than reported by the Environmental Protection Agency (EPA) but below the usually observed leakage rates over the shale gases in the US.more » Thanks to the high production rates on average at each well, leakage rates normalized by production appeared to be low in the northeastern Marcellus shale. This result confirms that natural gas production using unconventional techniques in this region is emitting relatively less CH 4 into the atmosphere than other shale reservoirs. The low emissions rate can be explained in part by the high productivity of wells drilled across the northeastern Marcellus region. We demonstrated here that atmospheric monitoring techniques can provide an independent quantification of NG leakage rates using aircraft measurements. The CH 4 analyzers were successfully calibrated at four sites across the region, measuring continuously the atmospheric CH 4 mixing ratios and isotopic 13Ch 4. Our preliminary findings confirm the low leakage rates from tower data collected over September 2015 to November 2016 compared to the aircraft mass-balance estimates in may 2015. However, several episodes revealing large releases of natural gas over several weeks showed that temporal variations in the emissions of CH 4 may increase the actual leakage rate over longer time periods.« less

Report of the River Master of the Delaware River for the period December 1, 1985, to November 30, 1986

USGS Publications Warehouse

Sauer, S.P.; Harkness, W.E.; Krejmas, B.E.; Vogel, K.L.

1987-01-01

A Decree of the Supreme Court of the United States in 1954 established the position of Delaware River Master. The Decree authorizes diversions of water from the Delaware River Basin (Figure 1) and requires compensating releases from certain reservoirs of the City of New York to be made under the supervision and direction of the River Master. Reports to the Court, not less frequently than annually, were stipulated. During the 1986 report year, December 1, 1985, to November 30, 1986, precipitation and runoff varied from below average to above average in the Delaware River Basin. For the year as a whole, precipitation was 4.3 inches above average. Runoff was near average. Operations were under a status of drought at the beginning of the report year. The drought emergency was terminated on December 18, 1985, by the Delaware River Basin Commission, and operations were returned to normal as prescribed by the Decree for the remainder of the report yr. Storage in the reservoirs increased to capacity during the winter months and all New York City Delaware River Basin reservoirs spilled throughout the year. Diversions from Delaware River Basin by New York City and New Jersey did not exceed those authorized by the terms of the Amended Decree. Releases were made as directed by the River Master at rates designed to meet the Montague flow objective on 69 days during the June to November period. Releases were made at conservation rates or at rates designed to relieve thermal stress in the streams downstream from the reservoirs at other times. The excess release quantity as defined by the Decree was not expended by end of the report year. New York City complied fully with the terms of the Decree and with the directives of the River Master during the year. (See also W89-04133) (USGS)

Regulation of exosome release from mammary epithelial and breast cancer cells - a new regulatory pathway.

PubMed

Riches, Andrew; Campbell, Elaine; Borger, Eva; Powis, Simon

2014-03-01

Exosomes are small 50-100nm sized extracellular vesicles released from normal and tumour cells and are a source of a new intercellular communication pathway. Tumour exosomes promote tumour growth and progression. What regulates the release and homoeostatic levels of exosomes, in cancer, in body fluids remains undefined. We utilised a human mammary epithelial cell line (HMEC B42) and a breast cancer cell line derived from it (B42 clone 16) to investigate exosome production and regulation. Exosome numbers were quantified using a Nanosight LM10 and measured in culture supernatants in the absence and presence of exosomes in the medium. Concentrated suspensions of exosomes from the normal mammary epithelial cells, the breast cancer cells and bladder cancer cells were used. The interaction of exosomes with tumour cells was also investigated using fluorescently labelled exosomes. Exosome release from normal human mammary epithelial cells and breast cancer cells is regulated by the presence of exosomes, derived from their own cells, in the extracellular environment of the cells. Exosomes from normal mammary epithelial cells also inhibit exosome secretion by breast cancer cells, which occurs in a tissue specific manner. Labelled exosomes from mammary epithelial cells are internalised into the tumour cells implicating a dynamic equilibrium and suggesting a mechanism for feedback control. These data suggest a previously unknown novel feedback regulatory mechanism for controlling exosome release, which may highlight a new therapeutic approach to controlling the deleterious effects of tumour exosomes. This regulatory mechanism is likely to be generic to other tumours. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of myofascial release after high-intensity exercise: a randomized clinical trial.

PubMed

Arroyo-Morales, Manuel; Olea, Nicolas; Martinez, Manuel; Moreno-Lorenzo, Carmen; Díaz-Rodríguez, Lourdes; Hidalgo-Lozano, Amparo

2008-03-01

The usefulness of massage as a recovery method after high-intensity exercise has yet to be established. We aimed to investigate the effects of whole-body massage on heart rate variability (HRV) and blood pressure (BP) after repeated high-intensity cycling exercise under controlled and standardized pretest conditions. The study included 62 healthy active individuals. After baseline measurements, the subjects performed standardized warm-up exercises followed by three 30-second Wingate tests. After completing the exercise protocol, the subjects were randomly assigned to a massage (myofascial release) or placebo (sham treatment with disconnected ultrasound and magnetotherapy equipment) group for a 40-minute recovery period. Holter recording and BP measurements were taken after exercise protocol and after the intervention. After the exercise protocol, both groups showed a significant decrease in normal-to-normal interval, HRV index, diastolic BP (P > .001), and low-frequency domain values (P = .006). After the recovery period, HRV index (P = .42) and high-frequency (HF) (P = .94) values were similar to baseline levels in the massage group, whereas the HRV index tended (P = .05) to be lower and the HF was significantly (P < .01) lower vs baseline values in the placebo group, which also showed a tendency (P = .06) for HF to be lower than after the exercise. Likewise, diastolic BP returned to baseline levels in the massage group (P = .45) but remained lower in the placebo group (P = .02). Myofascial release massage favors the recovery of HRV and diastolic BP after high-intensity exercise (3 Wingate tests) to preexercise levels.

Levonorgestrel release rates over 5 years with the Liletta® 52-mg intrauterine system.

PubMed

Creinin, Mitchell D; Jansen, Rolf; Starr, Robert M; Gobburu, Joga; Gopalakrishnan, Mathangi; Olariu, Andrea

2016-10-01

To understand the potential duration of action for Liletta®, we conducted this study to estimate levonorgestrel (LNG) release rates over approximately 5½years of product use. Clinical sites in the U.S. Phase 3 study of Liletta collected the LNG intrauterine systems (IUSs) from women who discontinued the study. We randomly selected samples within 90-day intervals after discontinuation of IUS use through 900days (approximately 2.5years) and 180-day intervals for the remaining duration through 5.4years (1980days) to evaluate residual LNG content. We also performed an initial LNG content analysis using 10 randomly selected samples from a single lot. We calculated the average ex vivo release rate using the residual LNG content over the duration of the analysis. We analyzed 64 samples within 90-day intervals (range 6-10 samples per interval) through 900days and 36 samples within 180-day intervals (6 samples per interval) for the remaining duration. The initial content analysis averaged 52.0±1.8mg. We calculated an average initial release rate of 19.5mcg/day that decreased to 17.0, 14.8, 12.9, 11.3 and 9.8mcg/day after 1, 2, 3, 4 and 5years, respectively. The 5-year average release rate is 14.7mcg/day. The estimated initial LNG release rate and gradual decay of the estimated release rate are consistent with the target design and function of the product. The calculated LNG content and release rate curves support the continued evaluation of Liletta as a contraceptive for 5 or more years of use. Liletta LNG content and release rates are comparable to published data for another LNG 52-mg IUS. The release rate at 5years is more than double the published release rate at 3years with an LNG 13.5-mg IUS, suggesting continued efficacy of Liletta beyond 5years. Copyright © 2016 Elsevier Inc. All rights reserved.

[Effect of glucocorticoides on the release of amino acids in the perfused rat hindquarter (author's transl)].

PubMed

Thienhaus, R; Tharandt, L; Zais, U; Staib, W

1975-06-01

The release of amino acids by skeletal muscle was studied in the isolated perfused rat hindquarter. Adrenalectomy depressed the formation of glutamine and alanine as well as the efflux of all other amino acids measured. Betamethasone--a synthetic glucocorticoid--caused a significant increase in the efflux of nearly all amino acids up to the level of normal controls. The release of amino acids was also increased in perfused hindquarters of diabetic rats. On the other hand, insulin exhibited a depressing effect on the release of amino acids by hindquarters of normal rats. The metabolic integrity of the muscle tissue was proved by measuring creatine phosphate, ATP, ADP and water content as well as by the significant insulin effect on glucose uptake and on [14C]leucine incorporation into muscle proteins.

Masking Release in Children and Adults with Hearing Loss When Using Amplification

ERIC Educational Resources Information Center

Brennan, Marc; McCreery, Ryan; Kopun, Judy; Lewis, Dawna; Alexander, Joshua; Stelmachowicz, Patricia

2016-01-01

Purpose: This study compared masking release for adults and children with normal hearing and hearing loss. For the participants with hearing loss, masking release using simulated hearing aid amplification with 2 different compression speeds (slow, fast) was compared. Method: Sentence recognition in unmodulated noise was compared with recognition…

Listeners Experience Linguistic Masking Release in Noise-Vocoded Speech-in-Speech Recognition

ERIC Educational Resources Information Center

Viswanathan, Navin; Kokkinakis, Kostas; Williams, Brittany T.

2018-01-01

Purpose: The purpose of this study was to evaluate whether listeners with normal hearing perceiving noise-vocoded speech-in-speech demonstrate better intelligibility of target speech when the background speech was mismatched in language (linguistic release from masking [LRM]) and/or location (spatial release from masking [SRM]) relative to the…

Development of an osmotic pump system for controlled delivery of diclofenac sodium.

PubMed

Emara, L H; Taha, N F; Badr, R M; Mursi, N M

2012-10-01

Based on an elementary osmotic pump, controlled release systems of diclofenac sodium (DS) were designed to deliver the drug in a zero-order release pattern. Osmotic pump tablets containing 100 mg DS were prepared and coated with either semipermeable (SPM) or microporous (PM) membranes. The tablet coats were composed of hydrophobic triacetin (TA) or hydrophilic polyethylene glycol 400 (PEG 400) incorporated in cellulose acetate (CA) solution, for SPM and PM, respectively. Variable tablet core compositions such as swelling polymers (PEO and HPMC) and osmotic agents (lactose, NaCl, and KCl) were studied. An optimized, sensitive and well controlled in vitro release design, based on the flow-through cell (FTC), was utilized to discriminate between preparations. The results revealed that the presence of PEG 400 in the coating membrane accelerated the drug release rate, while TA suppressed the release rate of DS. In the case of SPM, the amount of DS released was inversely proportional to the membrane thickness, where 5% (w/w) weight gain gave a higher DS release rate than 10% (w/w). Results of different tablet core compositions revealed that the release rate of DS decreased as PEO molecular weight increased. HPMC K15M showed the lowest DS release rate. The presence of lactose, KCl, or NaCl pronouncedly affected DS release rate depending on polymer type in the core. Scanning electron microscopy (SEM) confirmed formation of pores in the membrane that accounts for faster DS release rate. These results revealed that DS could be formulated as an osmotic pump system with a prolonged, zero-order release pattern.

Metal release rate from AISI 316L stainless steel and pure Fe, Cr and Ni into a synthetic biological medium--a comparison.

PubMed

Herting, G; Wallinder, I Odnevall; Leygraf, C

2008-09-01

Metal release rates from stainless steel grade 316L were investigated in artificial lysosomal fluid (ALF), simulating a human inflammatory cell response. The main focus was placed on release rates of main alloying elements using graphite furnace atomic absorption spectroscopy, and changes in surface oxide composition by means of X-ray photoelectron spectroscopy. To emphasise that alloys and pure metals possess totally different intrinsic properties, comparative studies were performed on the pure alloying constituents: iron, nickel and chromium. Significant differences in release rates were observed due to the presence of a passive surface film on stainless steel. Iron and nickel were released at rates more than 300 times lower from the 316L alloy compared with the pure metals whereas the release rate of chromium was similar. Iron was preferentially released compared with nickel and chromium. Immersion in ALF resulted in the gradual enrichment of chromium in the surface film, a small increase of nickel, and the reduction of oxidized iron with decreasing release rates of alloy constituents as a result. As expected, released metals from stainless steel grade 316L were neither in proportion to the bulk alloy composition nor to the surface film composition.

Experimental evidence for mobility of Zr and other trace elements in soils

NASA Astrophysics Data System (ADS)

Hodson, Mark E.

2002-03-01

A Soxhlet extraction was carried out over a period of 27 d on a column comprising 3 cm of quartz overlain by 4 cm of soil from the B horizon and then 1 cm of soil from the A horizon of a granitic podzol. Major and trace elements were leached from the column and accumulated in a reservoir at the base of the column. Total loss of elements from the soil over the course of the experiment ranged from 0.002 to 1 wt% with major elements and the light and heavy rare earth elements (REE) showing the largest percentage losses. Zirconium (0.002%) and then Al (0.008%) showed the lowest percentage loss. The light REE were leached out of the soil preferentially to the mid REE. All elements showed accumulation, by a factor of 2 to 11, in the quartz layers at the base of the column, particularly in the upper first 1 cm of the quartz. Major elements were leached from the column at a rate of 0.02 to 0.59 μmol h-1 whereas Zr, Nd, Sm, Gd, Dy, Rb, and Sr were leached at the rate of 0.5 to 30 × 10-6 μmol h-1. Concentrations of other REE in the reservoir increased over the duration of the experiment, but they were poorly correlated with time, so leaching rates were not calculated. Normalization of the major element leaching rates to take into account the constant flushing of water through the column, the average annual rainfall in the Allt a'Mharcaidh catchment in Scotland from where the soil was sampled, and the cross-sectional area of the soil in the column, together with the temperature of the soil in the column (70°C) compared with the average annual temperature of the Allt a'Mharcaidh catchment (5.7°C), gave major element release rates from the soil of 0.002 to 0.97 mEq m-2 yr-1 (depending on the choice of Ea, the dissolution activation energy), which are generally less than those measured in the field of 0.1 to 40.9 mEq m-2 yr-1. Calculations showed that despite the redistribution and loss of Zr from the column, assumptions of Zr mobility would have had a negligible effect on calculated element release rates of Na, Ca, Fe, and Mg. However, significant underestimates of the release of K (5%), Ti (57%), Al (5%), and Si (10%) as well as some trace elements (e.g., Nd, 23%; Rb, 54%; Sr, 24%) would have occurred. Concentrations of Ca and Sr leached from the column correlated well (RSQ = 0.93, p < 0.01), supporting the idea of the use of Sr release as a proxy for Ca release in weathering rate calculations. The release rates and percentage loss of REE from the soil varied between elements indicating that REE distribution patterns of rocks and soils may not be preserved in drainage waters.

The power of environment.

PubMed

Westbury, Becky

2015-06-01

In Ten tips for normal birth, the Royal College of Midwives (RCM) (2014) advocates the building of nests; creating an environment that helps women to feel safe and secure during birth, as this can improve women's experiences and likelihood of normal birth. Furthermore, a private, undisturbed and dark environment, where women feel calm and safe can promote the release of oxytocin, the hormone responsible for uterine contractions and thought to promote the release of the pain relieving hormones endorphins (Uvnas Moberg 2003). When this is not achieved, women can experience fear-tension-pain syndrome, impeding labour progress and causing increased levels of pain (Dick-Read 2013). In addition, birth space has the potential to encourage the promotion of normality through providing space to mobilise, and alternative furniture to enable upright birth positions. Midwives should help women to create a birth space in which they feel safe, calm and secure, to promote normality and increase the incidence of normal birth (RCM 2014).

Nanostructured lipid carriers: effect of solid phase fraction and distribution on the release of encapsulated materials.

PubMed

Dan, Nily

2014-11-25

Emulsions, solid lipid nanoparticles (SLN), and nanostructured lipid carriers (NLC) containing a mix of liquid and solid domains are of interest as encapsulation vehicles for hydrophobic compounds. Studies of the release rate from these particles yield contradictory results: Some find that increasing the fraction of solid phase increases the rate of release and others the opposite. In this paper we study the release of encapsulated materials from lipid-based nanoparticles using Monte Carlo simulations. We find that, quite surprisingly, the release rate is largely insensitive to the size of solid domains or the fraction of solid phase. However, the distribution of the domains significantly affects the rate of release: Solid domains located at the interface with the surrounding solution inhibit transport, while nanoparticles where the solid domains are concentrated in the center enhance it. The latter can lead to release rates in NLCs that are faster than in the equivalent emulsions. We conclude that controlling the release rate from NLCs requires the ability to determine the location and distribution of the solid phase, which may be achieved through choice of the surfactants stabilizing the particles, incorporation of nucleation sites, and/or the cooling rates and temperatures.

Preparation and evaluation of a controlled drug release of repaglinide through matrix pellets: in vitro and in vivo studies.

PubMed

Tavakoli, Naser; Minaiyan, Mohsen; Tabbakhian, Majid; Pendar, Yaqub

2014-01-01

Repaglinide, an oral antidiabetic agent, has a rapid onset of action and short half-life of approximately 1 h. Designing a controlled release dosage form of the drug is required to maintain its therapeutic blood level and to eliminate its adverse effects, particularly the hypoglycaemia. Repaglinide sustained release matrix pellets consisting of Avicel, lactose and different polymers were prepared using extrusion-spheronisation method. The effect of different formulation components on in vitro drug release were evaluated using USP apparatus (paddle) for 12 h in phosphate buffer. The optimised formulation was orally administrated to normal and STZ induced diabetic rats. Most pellet formulations had acceptable physical properties with regard to size distribution, flowability and friability. Repaglinide pellets comprising Avicel 50%, lactose 47% and SLS 1% were released 94% of its drug content after 12 h. The optimised formulation was able to decrease blood glucose level in normal rats and those with diabetes throughout 8-12 h.

CO2-induced pH reduction increases physiological toxicity of nano-TiO2 in the mussel Mytilus coruscus

PubMed Central

Hu, Menghong; Lin, Daohui; Shang, Yueyong; Hu, Yi; Lu, Weiqun; Huang, Xizhi; Ning, Ke; Chen, Yimin; Wang, Youji

2017-01-01

The increasing usage of nanoparticles has caused their considerable release into the aquatic environment. Meanwhile, anthropogenic CO2 emissions have caused a reduction of seawater pH. However, their combined effects on marine species have not been experimentally evaluated. This study estimated the physiological toxicity of nano-TiO2 in the mussel Mytilus coruscus under high pCO2 (2500–2600 μatm). We found that respiration rate (RR), food absorption efficiency (AE), clearance rate (CR), scope for growth (SFG) and O:N ratio were significantly reduced by nano-TiO2, whereas faecal organic weight rate and ammonia excretion rate (ER) were increased under nano-TiO2 conditions. High pCO2 exerted lower effects on CR, RR, ER and O:N ratio than nano-TiO2. Despite this, significant interactions of CO2-induced pH change and nano-TiO2 were found in RR, ER and O:N ratio. PCA showed close relationships among most test parameters, i.e., RR, CR, AE, SFG and O:N ratio. The normal physiological responses were strongly correlated to a positive SFG with normal pH and no/low nano-TiO2 conditions. Our results indicate that physiological functions of M. coruscus are more severely impaired by the combination of nano-TiO2 and high pCO2. PMID:28054631

CO2-induced pH reduction increases physiological toxicity of nano-TiO2 in the mussel Mytilus coruscus

NASA Astrophysics Data System (ADS)

Hu, Menghong; Lin, Daohui; Shang, Yueyong; Hu, Yi; Lu, Weiqun; Huang, Xizhi; Ning, Ke; Chen, Yimin; Wang, Youji

2017-01-01

The increasing usage of nanoparticles has caused their considerable release into the aquatic environment. Meanwhile, anthropogenic CO2 emissions have caused a reduction of seawater pH. However, their combined effects on marine species have not been experimentally evaluated. This study estimated the physiological toxicity of nano-TiO2 in the mussel Mytilus coruscus under high pCO2 (2500-2600 μatm). We found that respiration rate (RR), food absorption efficiency (AE), clearance rate (CR), scope for growth (SFG) and O:N ratio were significantly reduced by nano-TiO2, whereas faecal organic weight rate and ammonia excretion rate (ER) were increased under nano-TiO2 conditions. High pCO2 exerted lower effects on CR, RR, ER and O:N ratio than nano-TiO2. Despite this, significant interactions of CO2-induced pH change and nano-TiO2 were found in RR, ER and O:N ratio. PCA showed close relationships among most test parameters, i.e., RR, CR, AE, SFG and O:N ratio. The normal physiological responses were strongly correlated to a positive SFG with normal pH and no/low nano-TiO2 conditions. Our results indicate that physiological functions of M. coruscus are more severely impaired by the combination of nano-TiO2 and high pCO2.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dewitt, Ann E.; Dong, Jian Y.; Wiley, H S.

Autocrine signaling is important in normal tissue physiology as well as pathological conditions. It is difficult to analyze these systems, however, because they are both self-contained and recursive. To understand how parameters, such as ligand production and receptor expression influence autocrine activity, we investigated a human epidermal growth factor/epidermal growth factor receptor (EGF/EGFR) loop engineered into mouse B82 fibroblasts. We varied the level of ligand production using the tet-off expression system and used metalloprotease inhibitors to modulate ligand release. Receptor expression was varied using antagonistic, blocking antibodies. We compared autocrine ligand release to receptor activation using a microphysiometer-based assay andmore » analyzed our data with a quantitative model of ligand release and receptor dynamics. We found that the activity of our autocrine system could be described in terms of a simple ratio between the rate of ligand production (VL) and the rate of receptor production (VR). At a VL/VR ratio of < 0.3, essentially no ligand was found in the extracellular medium, but a significant number cell receptors (30-40%) were occupied. As the VL/VR ratio increased from 0.3 towards unity, receptor occupancy increased, and significant amounts of ligand now appeared in the medium. Above a VL/VR ratio of 1.0, receptor occupancy approached saturation and most of the released ligand was lost into the medium. Analysis of human mammary epithelial cells showed that a VL/VR ratio of < 5 x 10 -4 was sufficient to evoke >20% of a maximal proliferative response. This suggests that natural autocrine systems are active even when no ligand appears in the extracellular medium; i.e., they operate 'invisibly' to general detection.« less

Glass-bonded iodosodalite waste form for immobilization of 129 I

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chong, Saehwa; Peterson, Jacob A.; Riley, Brian J.

Immobilization of radioiodine (e.g., 129I, 131I) is an important need for current and future nuclear fuel cycles. For the current work, iodosodalite [Na8(AlSiO4)6I2] was synthesized hydrothermally from metakaolin, NaI, and NaOH. Following hydrothermal treatment, dried unwashed powders were used to make glass-bonded iodosodalite waste forms by heating pressed pellets at 650, 750, or 850 °C with two different types of sodium borosilicate glass binders, i.e., NBS-4 and SA-800. These heat-treated specimens were characterized with X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, thermal analysis, porosity and density measurements, neutron activation analysis, and inductively-coupled plasma mass spectrometry. Themore » pellets mixed with 10 mass% of NBS-4 or SA-800 and heat-treated at 750 °C contained relatively high percentage iodine retention (~44-47 % of the maximum iodine loading) with relatively low porosities, while other pellets with higher percentages iodine retention either contained higher porosity or were not completely sintered. ASTM C1308 chemical durability tests of monolithic specimens showed a large initial release of Na, Al, Si, and I on the first day, possibly from water-soluble salt crystals or non-durable amorphous phases. Release rates of Na and Si were higher than for Al and I, probably due to a poorly durable Na-Si-O phase from the glass bonding matrix. The cumulative normalized release of iodine was 12.5 g m-2 for the first 10 1-d exchanges, suggestive of coherent dissolution. The average release rate from 10-24 days during the 7-d exchange intervals was 0.2336 g m-2 d-1.« less

Serial assessment of the physiological status of leatherback turtles (Dermochelys coriacea) during direct capture events in the northwestern Atlantic Ocean: comparison of post-capture and pre-release data.

PubMed

Innis, Charles J; Merigo, Constance; Cavin, Julie M; Hunt, Kathleen; Dodge, Kara L; Lutcavage, Molly

2014-01-01

The physiological status of seven leatherback turtles (Dermochelys coriacea) was assessed at two time points during ecological research capture events in the northwestern Atlantic Ocean. Data were collected as soon as possible after securing each turtle onboard the capture vessel and again immediately prior to release. Measured parameters included sea surface temperature, body temperature, morphometric data, sex, heart rate, respiratory rate and various haematological and blood biochemical variables. Results indicated generally stable physiological status in comparison to previously published studies of this species. However, blood pH and blood potassium concentrations increased significantly between the two time points (P = 0.0018 and P = 0.0452, respectively). Turtles were affected by a mild initial acidosis (mean [SD] temperature-corrected pH = 7.29 [0.07]), and blood pH increased prior to release (mean [SD] = 7.39 [0.07]). Initial blood potassium concentrations were considered normal (mean [SD] = 4.2 [0.9] mmol/l), but turtles experienced a mild to moderate increase in blood potassium concentrations during the event (mean [SD] pre-release potassium = 5.9 [1.7] mmol/l, maximum = 8.5 mmol/l). While these data support the general safety of direct capture for study of this species, the observed changes in blood potassium concentrations are of potential concern due to possible adverse effects of hyperkalaemia on cardiac function. The results of this study highlight the importance of physiological monitoring during scientific capture events. The results are also likely to be relevant to unintentional leatherback capture events (e.g. fisheries interactions), when interactions may be more prolonged or extreme.

Congenital isolated thyrotrophin releasing hormone deficiency

PubMed Central

Niimi, H; Inomata, H; Sasaki, N; Nakajima, H

1982-01-01

A 4⅓-year-old girl with congenital thyrotrophin-releasing hormone (TRH) deficiency is described. Oral TRH administration led to normal thyroid hormone and TRH levels in the blood; favourable growth and development was achieved. PMID:6816148

Modelling and assessment of accidental oil release from damaged subsea pipelines.

PubMed

Li, Xinhong; Chen, Guoming; Zhu, Hongwei

2017-10-15

This paper develops a 3D, transient, mathematical model to estimate the oil release rate and simulate the oil dispersion behavior. The Euler-Euler method is used to estimate the subsea oil release rate, while the Eulerian-Lagrangian method is employed to track the migration trajectory of oil droplets. This model accounts for the quantitative effect of backpressure and hole size on oil release rate, and the influence of oil release rate, oil density, current speed, water depth and leakage position on oil migration is also investigated in this paper. Eventually, the results, e.g. transient release rate of oil, the rise time of oil and dispersion distance are determined by above-mentioned model, and the oil release and dispersion behavior under different scenarios is revealed. Essentially, the assessment results could provide a useful guidance for detection of leakage positon and placement of oil containment boom. Copyright © 2017 Elsevier Ltd. All rights reserved.

Acoustic measurement of the Deepwater Horizon Macondo well flow rate

PubMed Central

Camilli, Richard; Di Iorio, Daniela; Bowen, Andrew; Reddy, Christopher M.; Techet, Alexandra H.; Yoerger, Dana R.; Whitcomb, Louis L.; Seewald, Jeffrey S.; Sylva, Sean P.; Fenwick, Judith

2012-01-01

On May 31, 2010, a direct acoustic measurement method was used to quantify fluid leakage rate from the Deepwater Horizon Macondo well prior to removal of its broken riser. This method utilized an acoustic imaging sonar and acoustic Doppler sonar operating onboard a remotely operated vehicle for noncontact measurement of flow cross-section and velocity from the well’s two leak sites. Over 2,500 sonar cross-sections and over 85,000 Doppler velocity measurements were recorded during the acquisition process. These data were then applied to turbulent jet and plume flow models to account for entrained water and calculate a combined hydrocarbon flow rate from the two leak sites at seafloor conditions. Based on the chemical composition of end-member samples collected from within the well, this bulk volumetric rate was then normalized to account for contributions from gases and condensates at initial leak source conditions. Results from this investigation indicate that on May 31, 2010, the well’s oil flow rate was approximately 0.10 ± 0.017 m3 s-1 at seafloor conditions, or approximately 85 ± 15 kg s-1 (7.4 ± 1.3 Gg d-1), equivalent to approximately 57,000 ± 9,800 barrels of oil per day at surface conditions. End-member chemical composition indicates that this oil release rate was accompanied by approximately an additional 24 ± 4.2 kg s-1 (2.1 ± 0.37 Gg d-1) of natural gas (methane through pentanes), yielding a total hydrocarbon release rate of 110 ± 19 kg s-1 (9.5 ± 1.6 Gg d-1). PMID:21903931

Exploratory results from a new rotary shear designed to reproduce the extreme deformation conditions of crustal earthquakes

NASA Astrophysics Data System (ADS)

Di Toro, G.; Nielsen, S. B.; Spagnuolo, E.; Smith, S.; Violay, M. E.; Niemeijer, A. R.; Di Felice, F.; Di Stefano, G.; Romeo, G.; Scarlato, P.

2011-12-01

A challenging goal in experimental rock deformation is to reproduce the extreme deformation conditions typical of coseismic slip in crustal earthquakes: large slip (up to 50 m), slip rates (0.1-10 m/s), accelerations (> 10 m/s2) and normal stress (> 50 MPa). Moreover, fault zones usually contain non-cohesive rocks (gouges) and fluids. The integration of all these deformation conditions is such a technical challenge that there is currently no apparatus in the world that can reproduce seismic slip. Yet, the determination of rock friction at seismic slip rates remains one of the main unknowns in earthquake physics, as it cannot be determined (or very approximately) by seismic wave inversion analysis. In the last thirty years, rotary shear apparatus were designed that combine large normal stresses and slip but low slip rates (high-pressure rotary shears first designed by Tullis) or low normal stresses but large slip rates and slip (rotary shears first designed by Shimamoto). Here we present the results of experiments using a newly-constructed Slow to HIgh Velocity Apparatus (SHIVA), installed at INGV in Rome, which extends the combination of normal stress, slip and slip rate achieved by previous apparatus and reproduces the conditions likely to occur during an earthquake in the shallow crust. SHIVA uses two brushless engines (max power 300 kW, max torque 930 Nm) and an air actuator (thrust 5 tons) in a rotary shear configuration (nominally infinite displacement) to slide hollow rock cylinders (30/50 mm int./ext. diameter) at slip rates ranging from 10 micron/s up to 6.5 m/s, accelerations up to 80 m/s2 and normal stresses up to 50 MPa. SHIVA can also perform experiments in which the torque on the sample (rather than the slip rate) is progressively increased until spontaneous failure occurs: this experimental capability should better reproduce natural conditions. The apparatus is equipped with a sample chamber to carry out experiments in the presence of fluids (up to 15 MPa fluid pressure), devices to determine the fluid composition during sliding, a gouge sample holder (tested up to 34 MPa in normal stress), and an environmental/vacuum chamber connected to a mass spectrometer to measure gas release during frictional sliding. In particular, we will show: 1) the extremely low friction coefficients (often approaching zero) and short (few cm is some cases) slip weakening distances measured in experiments performed at large normal stress (<40MPa) and accelerations on cohesive rocks (carbonatic marbles and gabbros); 2) the spontaneous creep episodes, lasting a few mm to a few cm in slip, that precede the large stress drops typical of earthquake instabilities, observed in torque-controlled experiments on gabbro and marbles; 3) how the presence of free fluids (H2O) delays the onset of dynamic weakening in carbonatic rocks; 4) the experimental microstructures, produced at normal stresses up to 34 MPa and slip rates of 1-3 m/s, in calcite gouges that closely resemble those found in exhumed seismic fault zones.

How clarinettists articulate: The effect of blowing pressure and tonguing on initial and final transients.

PubMed

Li, Weicong; Almeida, André; Smith, John; Wolfe, Joe

2016-02-01

Articulation, including initial and final note transients, is important to tasteful music performance. Clarinettists' tongue-reed contact, the time variation of the blowing pressure P¯mouth, the mouthpiece pressure, the pressure in the instrument bore, and the radiated sound were measured for normal articulation, accents, sforzando, staccato, and for minimal attack, i.e., notes started very softly. All attacks include a phase when the amplitude of the fundamental increases exponentially, with rates r ∼1000 dB s(-1) controlled by varying both the rate of increase in P¯mouth and the timing of tongue release during this increase. Accented and sforzando notes have shorter attacks (r∼1300 dB s(-1)) than normal notes. P¯mouth reaches a higher peak value for accented and sforzando notes, followed by a steady decrease for accented notes or a rapid fall to a lower, nearly steady value for sforzando notes. Staccato notes are usually terminated by tongue contact, producing an exponential decrease in sound pressure with rates similar to those calculated from the bandwidths of the bore resonances: ∼400 dB s(-1). In all other cases, notes are stopped by decreasing P¯mouth. Notes played with different dynamics are qualitatively similar, but louder notes have larger P¯mouth and larger r.

The Human Sympathetic Nervous System Response to Spaceflight

NASA Technical Reports Server (NTRS)

Ertl, Andrew C.; Diedrich, Andre; Paranjape, Sachin Y.; Biaggioni, Italo; Robertson, Rose Marie; Lane, Lynda D.; Shiavi, Richard; Robertson, David

2003-01-01

The sympathetic nervous system is an important part of the autonomic (or automatic) nervous system. When an individual stands up, the sympathetic nervous system speeds the heart and constricts blood vessels to prevent a drop in blood pressure. A significant number of astronauts experience a drop in blood pressure when standing for prolonged periods after they return from spaceflight. Difficulty maintaining blood pressure with standing is also a daily problem for many patients. Indirect evidence available before the Neurolab mission suggested the problem in astronauts while in space might be due partially to reduced sympathetic nervous system activity. The purpose of this experiment was to identify whether sympathetic activity was reduced during spaceflight. Sympathetic nervous system activity can be determined in part by measuring heart rate, nerve activity going to blood vessels, and the release of the hormone norepinephrine into the blood. Norepinephrine is a neurotransmitter discharged from active sympathetic nerve terminals, so its rate of release can serve as a marker of sympathetic nervous system action. In addition to standard cardiovascular measurements (heart rate, blood pressure), we determined sympathetic nerve activity as well as norepinephrine release and clearance on four crewmembers on the Neurolab mission. Contrary to our expectation, the results demonstrated that the astronauts had mildly elevated resting sympathetic nervous system activity in space. Sympathetic nervous system responses to stresses that simulated the cardiovascular effects of standing (lower body negative pressure) were brisk both during and after spaceflight. We concluded that, in the astronauts tested, the activity and response of the sympathetic nervous system to cardiovascular stresses appeared intact and mildly elevated both during and after spaceflight. These changes returned to normal within a few days.

Influence of mastication rate on dynamic flavour release analysed by combined model mouth/proton transfer reaction-mass spectrometry

NASA Astrophysics Data System (ADS)

van Ruth, Saskia M.; Buhr, Katja

2004-12-01

The influence of mastication rate on the dynamic release of seven volatile flavour compounds from sunflower oil was evaluated by combined model mouth/proton transfer reaction-mass spectrometry (PTR-MS). Air/oil partition coefficients were measured by static headspace gas chromatography. The dynamic release of the seven volatile flavour compounds from sunflower oil was significantly affected by the compounds' hydrophobicity and the mastication rate employed in the model mouth. The more hydrophobic compounds were released at a higher rate than their hydrophilic counterparts. Increase in mastication rate increased the maximum concentration measured by 36% on average, and the time to reach this maximum by 35% on average. Mastication affected particularly the release of the hydrophilic compounds. The maximum concentration of the compounds correlated significantly with the compounds' air/oil partition coefficients. The initial release rates over the first 15 s were affected by the type of compound, but not by the mastication rate. During the course of release, the proportions of the hydrophilic compounds to the overall flavour mixture in air decreased. The contribution of the hydrophobic compounds increased. Higher mastication rates, however, increased the proportions of the hydrophilic compounds and decreased those of the hydrophobic compounds.

Heat release rate of wood-plastic composites

Treesearch

N. M. Stark; R. H. White; C. M. Clemons

1997-01-01

Wood-plastic composites are becoming more important as a material that fulfills recycling needs. In this study, fire performance tests were conducted on several compositions of wood and plastic materials using the Ohio State University rate of heat release apparatus. Test results included five-minute average heat release rate in kW/m2 (HRR avg) and maximum heat release...

Heat release and flame structure measurements of self-excited acoustically-driven premixed methane flames

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kopp-Vaughan, Kristin M.; Tuttle, Steven G.; Renfro, Michael W.

An open-open organ pipe burner (Rijke tube) with a bluff-body ring was used to create a self-excited, acoustically-driven, premixed methane-air conical flame, with equivalence ratios ranging from 0.85 to 1.05. The feed tube velocities corresponded to Re = 1780-4450. Coupled oscillations in pressure, velocity, and heat release from the flame are naturally encouraged at resonant frequencies in the Rijke tube combustor. This coupling creates sustainable self-excited oscillations in flame front area and shape. The period of the oscillations occur at the resonant frequency of the combustion chamber when the flame is placed {proportional_to}1/4 of the distance from the bottom ofmore » the tube. In this investigation, the shape of these acoustically-driven flames is measured by employing both OH planar laser-induced fluorescence (PLIF) and chemiluminescence imaging and the images are correlated to simultaneously measured pressure in the combustor. Past research on acoustically perturbed flames has focused on qualitative flame area and heat release relationships under imposed velocity perturbations at imposed frequencies. This study reports quantitative empirical fits with respect to pressure or phase angle in a self-generated pressure oscillation. The OH-PLIF images were single temporal shots and the chemiluminescence images were phase averaged on chip, such that 15 exposures were used to create one image. Thus, both measurements were time resolved during the flame oscillation. Phase-resolved area and heat release variations throughout the pressure oscillation were computed. A relation between flame area and the phase angle before the pressure maximum was derived for all flames in order to quantitatively show that the Rayleigh criterion was satisfied in the combustor. Qualitative trends in oscillating flame area were found with respect to feed tube flow rates. A logarithmic relation was found between the RMS pressure and both the normalized average area and heat release rate for all flames. (author)« less

Polymeric Multilayers that Localize the Release of Chlorhexidine from Biologic Wound Dressings

PubMed Central

Agarwal, Ankit; Nelson, Tyler B.; Kierski, Patricia R.; Schurr, Michael J.; Murphy, Christopher J.; Czuprynski, Charles J.; McAnulty, Jonathan F.; Abbott, Nicholas L.

2012-01-01

Biologic wound dressings contain animal-derived components and are susceptible to high infection rates. To address this issue, we report an approach that permits incorporation of non-toxic levels of the small-molecule antiseptic ‘chlorhexidine’ into biologic dressings. The approach relies on the fabrication of polyelectrolyte multilayer (PEMs) films containing poly(allylaminehydrochloride) (PAH), poly(acrylicacid) (PAA), and chlorhexidine acetate (CX) on elastomeric poly(dimethylsiloxane) (PDMS) sheets. The PEMs (20-100 nm thick) are subsequently stamped onto the wound-contact surface of a synthetic biologic dressing, Biobrane, which contains collagen peptides. Chlorhexidine loading in the PEMs was tailored by tuning the number of (CX/PAA) bilayers deposited, providing burst release of up to 0.98±0.06 μg/cm2 of CX over 24 h, followed by zero order release of 0.35±0.04 μg/cm2/day for another week. Although the CX concentrations released were below the reported in vitro cytotoxicity limit (5 μg/mL over 24 h) for human dermal fibroblasts, they killed 4 log10 counts of pathogenic bacteria Staphylococcus aureus in solution. The CX/PEMs could be stamped onto Biobrane with high efficiency to provide CX release kinetics and in-vitro antibacterial activity similar to that on PDMS stamps. In a full-thickness ‘splinted’ dermal wound-model in normal wild-type mice, the CX-functionalized Biobrane showed no decrease in either its adherence to the wound-bed or wound-closure rate over 14 days. The murine wounds topically inoculated with ~105 CFU/cm2 of S. aureus and treated with CX-functionalized Biobrane demonstrated a 3 log10 decrease in the wound's bacterial burden within 3 days, compared to persistent bacterial colonization found in wounds treated with unmodified Biobrane (n=10 mice, p<0.005). Overall, this study presents a promising approach to prevent bacterial colonization in wounds under biologic dressings. PMID:22784602

Distribution, origin and implications of seismic stress release in shallow and intermediate-depth subduction systems

NASA Astrophysics Data System (ADS)

Chen, Po-Fei

A characterization of focal mechanisms is developed for shallow and intermediate-depth earthquakes in the context of the local geometry of subduction systems. Its application to the Ryukyu-Taiwan-Luzon system is used to refine the spatial distribution of characteristic groups of earthquakes in the framework of local tectonic processes, such as flipping of the polarity of subduction and the nascent processes of arc-continent collision. The Harvard catalogue of Centroid Moment Tensor solutions is expanded to include intermediate-depth earthquakes from the WWSSN-HGLP era (1962--1975). Seventy-six new solutions are obtained, with the resulting dataset estimated to be complete for M0 ≥ 1026 dyn-cm. While source mechanisms from our new dataset are generally similar to those previously compiled in the Harvard catalogue, seismic moment release rates are found to be significantly smaller for the WWSSN era. The intermediate-depth seismicity of South America is compiled from the Harvard catalogue, using projection along local slab coordinates, to determine along-strike variations in the distribution of earthquakes and in the geometry of their stress release. Slab geometry is investigated in relation to slab stresses and the presence or absence of arc volcanism. Steeper-dipping slabs are found to exhibit consistent down-dip extension, a higher rate of seismic moment release and surface volcanism. Visualization using slab coordinate projections is extended systematically to a global survey of the geometry of stress release in intermediate-depth earthquakes. Various proposed models for all subduction zones are appraised, as contributors to stress regimes, based on global data compilations. Down-dip stresses, where prominent, are found to be consistent with the thermo-mechanical and petrological force models. Slab-normal conjugate stresses generally support the concept of earthquake reactivation of fossil faults. Patterns of lateral stresses support the predictions of the so-called "punctured-ping-pong-ball" model.

Quantitative importance of the 25-hydroxylation pathway for bile acid biosynthesis in the rat

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duane, W.C.; Bjoerkhem, I.H.; Hamilton, J.N.

1988-05-01

During biosynthesis of bile acid, carbons 25-26-27 are removed from the cholesterol side chain. Side-chain oxidation begins either with hydroxylation at the 26-position, in which case the three-carbon fragment is released as propionic acid, or with hydroxylation at the 25-position, in which case the three-carbon fragment is released as acetone. In the present study, we have quantitated the relative importance of these two pathways in vivo by measuring production of (14C) acetone from (14C)-26-cholesterol. Four days after intraperitoneal injection of 20 to 40 muCi (14C)-26-cholesterol and 1 day after beginning a constant intravenous infusion of unlabeled acetone at 25 mumolesmore » per kg per min, 6 male and 2 female Sprague-Dawley rats underwent breath collections. Expired acetone was trapped and purified as the 2,4-dinitrophenylhydrazine derivative. 14CO2 was trapped quantitatively using phenethylamine. Specific activity of breath acetone was multiplied times the acetone infusion rate to calculate production of (14C)acetone. (14C) Acetone production averaged 1.7% of total release of 14C from (14C)-26-cholesterol, estimated by 14CO2 output. The method was validated by showing that (14C) acetone production from (14C)isopropanol averaged 111% of the (14C)isopropanol infusion rate. We conclude that, in the normal rat, the 25-hydroxylation pathway accounts for less than 2% of bile acid synthesis.« less

Quantitative importance of the 25-hydroxylation pathway for bile acid biosynthesis in the rat.

PubMed

Duane, W C; Björkhem, I; Hamilton, J N; Mueller, S M

1988-01-01

During biosynthesis of bile acid, carbons 25-26-27 are removed from the cholesterol side chain. Side-chain oxidation begins either with hydroxylation at the 26-position, in which case the three-carbon fragment is released as propionic acid, or with hydroxylation at the 25-position, in which case the three-carbon fragment is released as acetone. In the present study, we have quantitated the relative importance of these two pathways in vivo by measuring production of [14C] acetone from [14C]-26-cholesterol. Four days after intraperitoneal injection of 20 to 40 muCi [14C]-26-cholesterol and 1 day after beginning a constant intravenous infusion of unlabeled acetone at 25 mumoles per kg per min, 6 male and 2 female Sprague-Dawley rats underwent breath collections. Expired acetone was trapped and purified as the 2,4-dinitrophenylhydrazine derivative. 14CO2 was trapped quantitatively using phenethylamine. Specific activity of breath acetone was multiplied times the acetone infusion rate to calculate production of [14C]acetone. [14C] Acetone production averaged 1.7% of total release of 14C from [14C]-26-cholesterol, estimated by 14CO2 output. The method was validated by showing that [14C] acetone production from [14C]isopropanol averaged 111% of the [14C]isopropanol infusion rate. We conclude that, in the normal rat, the 25-hydroxylation pathway accounts for less than 2% of bile acid synthesis.

Treatment of Low-Risk Endometrial Cancer and Complex Atypical Hyperplasia With the Levonorgestrel-Releasing Intrauterine Device.

PubMed

Pal, Navdeep; Broaddus, Russell R; Urbauer, Diana L; Balakrishnan, Nyla; Milbourne, Andrea; Schmeler, Kathleen M; Meyer, Larissa A; Soliman, Pamela T; Lu, Karen H; Ramirez, Pedro T; Ramondetta, Lois; Bodurka, Diane C; Westin, Shannon N

2018-01-01

To assess efficacy of the levonorgestrel-releasing intrauterine device (LNG-IUD) for treatment of complex atypical hyperplasia or low-grade endometrial cancer. This retrospective case series included all patients treated with the LNG-IUD for complex atypical hyperplasia or early-grade endometrial cancer from January 2003 to June 2013. Response rates were calculated and the association of response with clinicopathologic factors, including age, body mass index, and uterine size, was determined. Forty-six patients diagnosed with complex atypical hyperplasia or early-grade endometrial cancer were treated with the LNG-IUD. Of 32 evaluable patients at the 6-month time point, 15 had complex atypical hyperplasia (47%), nine had G1 endometrial cancer (28%), and eight had grade 2 endometrial cancer (25%). Overall response rate was 75% (95% CI 57-89) at 6 months; 80% (95% CI 52-96) in complex atypical hyperplasia, 67% (95% CI 30-93) in grade 1 endometrial cancer, and 75% (CI 35-97) in grade 2 endometrial cancer. Of the clinicopathologic features evaluated, there was a trend toward the association of lack of exogenous progesterone effect in the pathology specimen with nonresponse to the IUD (P=.05). Median uterine diameter was 1.3 cm larger in women who did not respond to the IUD (P=.04). Levonorgestrel-releasing IUD therapy for the conservative treatment of complex atypical hyperplasia or early-grade endometrial cancer resulted in return to normal histology in a majority of patients.

Burning rate of solid wood measured in a heat release rate calorimeter

Treesearch

H. C. Tran; R. H. White

1992-01-01

Burning rate is a key factor in modeling fire growth and fire endurance of wood structures. This study investigated the burning rate of selected wood materials as determined by heat release, mass loss and charring rates. Thick samples of redwood, southern pine, red oak and basswood were tested in a heat release rate calorimeter. Results on ignitability and average beat...

Comparison of the Kinetic Rate Law Parameters for the Dissolution of Natural and Synthetic Autunite in the Presence of Aqueous Bicarbonate Ions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gudavalli, Ravi; Katsenovich, Yelena; Wellman, Dawn M.

2013-08-02

Bicarbonate is one of the most significant components within the uranium geochemical cycle. In aqueous solutions, bicarbonate forms strong complexes with uranium. As such, aqueous bicarbonate may significantly increase the rate of uranium release from uranium minerals. Quantifying the relationship of aqueous bicarbonate concentration to the rate of uranium release during dissolution is critical to understanding the long-term fate of uranium within the environment. Single-pass flow-through (SPTF) experiments were conducted to estimate the rate of uranium release from Na meta-autunite as a function of bicarbonate (0.0005-0.003 M) under the pH range of 6-11 and a temperature range of 5-60oC. Consistentmore » with the results of previous investigation, the rate of uranium release exhibited minimal dependency on temperature; but were strongly dependent on pH. Increasing aqueous bicarbonate concentrations afforded comparable increases in the rate of release of uranium. Most notably under low pH conditions the aqueous bicarbonate resulted in up to 370 fold increases in the rate of uranium release in relative to the rate of uranium release in the absence of bicarbonate. However, the effect of aqueous bicarbonate on the release of uranium was significantly less under higher pH conditions. It is postulated that at high pH values, surface sites are saturated with carbonate, thus the addition of more bicarbonate would have less effect on uranium release.« less

Repair of radiation-induced heat-labile sites is independent of DNA-PKcs, XRCC1 or PARP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stenerlöw, Bo; Karlsson, Karin H.; Radulescu, Irina

2008-04-29

Ionizing radiation induces a variety of different DNA lesions: in addition to the most critical DNA damage, the DSB, numerous base alterations, SSBs and other modifications of the DNA double-helix are formed. When several non-DSB lesions are clustered within a short distance along DNA, or close to a DSB, they may interfere with the repair of DSBs and affect the measurement of DSB induction and repair. We have previously shown that a substantial fraction of DSBs measured by pulsed-field gel electrophoresis (PFGE) are in fact due to heat-labile sites (HLS) within clustered lesions, thus reflecting an artifact of preparation ofmore » genomic DNA at elevated temperature. To further characterize the influence of HLS on DSB induction and repair, four human cell lines (GM5758, GM7166, M059K, U-1810) with apparently normal DSB rejoining were tested for bi-phasic rejoining after gamma irradiation. When heat-released DSBs were excluded from the measurements the fraction of fast rejoining decreased to less than 50% of the total. However, neither the half-times of the fast (t{sub 1/2} = 7-8 min) or slow (t{sub 1/2} = 2.5 h) DSB rejoining were changed significantly. At t=0 the heat-released DSBs accounted for almost 40% of the DSBs, corresponding to 10 extra DSB/cell/Gy in the initial DSB yield. These heat-released DSBs were repaired within 60-90 min in all tested cells, including M059K cells treated with wortmannin or DNA-PKcs defect M059J cells. Furthermore, cells lacking XRCC1 or Poly(ADP-ribose) polymerase-1 (PARP-1) rejoined both total DSBs and heat-released DSBs similar to normal cells. In summary, the presence of heat-labile sites have a substantial impact on DSB induction yields and DSB rejoining rates measured by pulsed-field gel electrophoresis, and HLS repair is independent of DNA-PKcs, XRCC1 and PARP.« less

Circadian gene expression regulates pulsatile gonadotropin-releasing hormone (GnRH) secretory patterns in the hypothalamic GnRH-secreting GT1-7 cell line.

PubMed

Chappell, Patrick E; White, Rachel S; Mellon, Pamela L

2003-12-03

Although it has long been established that episodic secretion of gonadotropin-releasing hormone (GnRH) from the hypothalamus is required for normal gonadotropin release, the molecular and cellular mechanisms underlying the synchronous release of GnRH are primarily unknown. We used the GT1-7 mouse hypothalamic cell line as a model for GnRH secretion, because these cells release GnRH in a pulsatile pattern similar to that observed in vivo. To explore possible molecular mechanisms governing secretory timing, we investigated the role of the molecular circadian clock in regulation of GnRH secretion. GT1-7 cells express many known core circadian clock genes, and we demonstrate that oscillations of these components can be induced by stimuli such as serum and the adenylyl cyclase activator forskolin, similar to effects observed in fibroblasts. Strikingly, perturbation of circadian clock function in GT1-7 cells by transient expression of the dominant-negative Clock-Delta19 gene disrupts normal ultradian patterns of GnRH secretion, significantly decreasing mean pulse frequency. Additionally, overexpression of the negative limb clock gene mCry1 in GT1-7 cells substantially increases GnRH pulse amplitude without a commensurate change in pulse frequency, demonstrating that an endogenous biological clock is coupled to the mechanism of neurosecretion in these cells and can regulate multiple secretory parameters. Finally, mice harboring a somatic mutation in the Clock gene are subfertile and exhibit a substantial increase in estrous cycle duration as revealed by examination of vaginal cytology. This effect persists in normal light/dark (LD) cycles, suggesting that a suprachiasmatic nucleus-independent endogenous clock in GnRH neurons is required for eliciting normal pulsatile patterns of GnRH secretion.

Launch Lock Assemblies Including Axial Gap Amplification Devices and Spacecraft Isolation Systems Including the Same

NASA Technical Reports Server (NTRS)

Barber, Tim Daniel (Inventor); Hindle, Timothy (Inventor); Young, Ken (Inventor); Davis, Torey (Inventor)

2014-01-01

Embodiments of a launch lock assembly are provided, as are embodiments of a spacecraft isolation system including one or more launch lock assemblies. In one embodiment, the launch lock assembly includes first and second mount pieces, a releasable clamp device, and an axial gap amplification device. The releasable clamp device normally maintains the first and second mount pieces in clamped engagement; and, when actuated, releases the first and second mount pieces from clamped engagement to allow relative axial motion there between. The axial gap amplification device normally residing in a blocking position wherein the gap amplification device obstructs relative axial motion between the first and second mount pieces. The axial gap amplification device moves into a non-blocking position when the first and second mount pieces are released from clamped engagement to increase the range of axial motion between the first and second mount pieces.

Dissection of structural and functional requirements that underlie the interaction of ERdj3 protein with substrates in the endoplasmic reticulum.

PubMed

Otero, Joel H; Lizák, Beata; Feige, Matthias J; Hendershot, Linda M

2014-10-03

ERdj3, a mammalian endoplasmic reticulum (ER) Hsp40/DnaJ family member, binds unfolded proteins, transfers them to BiP, and concomitantly stimulates BiP ATPase activity. However, the requirements for ERdj3 binding to and release from substrates in cells are not well understood. We found that ERdj3 homodimers that cannot stimulate the ATPase activity of BiP (QPD mutants) bound to unfolded ER proteins under steady state conditions in much greater amounts than wild-type ERdj3. This was due to reduced release from these substrates as opposed to enhanced binding, although in both cases dimerization was strictly required for substrate binding. Conversely, heterodimers consisting of one wild-type and one mutant ERdj3 subunit bound substrates at levels comparable with wild-type ERdj3 homodimers, demonstrating that release requires only one protomer to be functional in stimulating BiP ATPase activity. Co-expressing wild-type ERdj3 and a QPD mutant, which each exclusively formed homodimers, revealed that the release rate of wild-type ERdj3 varied according to the relative half-lives of substrates, suggesting that ERdj3 release is an important step in degradation of unfolded client proteins in the ER. Furthermore, pulse-chase experiments revealed that the binding of QPD mutant homodimers remained constant as opposed to increasing, suggesting that ERdj3 does not normally undergo reiterative binding cycles with substrates. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Dissection of Structural and Functional Requirements That Underlie the Interaction of ERdj3 Protein with Substrates in the Endoplasmic Reticulum*

PubMed Central

Otero, Joel H.; Lizák, Beata; Feige, Matthias J.; Hendershot, Linda M.

2014-01-01

ERdj3, a mammalian endoplasmic reticulum (ER) Hsp40/DnaJ family member, binds unfolded proteins, transfers them to BiP, and concomitantly stimulates BiP ATPase activity. However, the requirements for ERdj3 binding to and release from substrates in cells are not well understood. We found that ERdj3 homodimers that cannot stimulate the ATPase activity of BiP (QPD mutants) bound to unfolded ER proteins under steady state conditions in much greater amounts than wild-type ERdj3. This was due to reduced release from these substrates as opposed to enhanced binding, although in both cases dimerization was strictly required for substrate binding. Conversely, heterodimers consisting of one wild-type and one mutant ERdj3 subunit bound substrates at levels comparable with wild-type ERdj3 homodimers, demonstrating that release requires only one protomer to be functional in stimulating BiP ATPase activity. Co-expressing wild-type ERdj3 and a QPD mutant, which each exclusively formed homodimers, revealed that the release rate of wild-type ERdj3 varied according to the relative half-lives of substrates, suggesting that ERdj3 release is an important step in degradation of unfolded client proteins in the ER. Furthermore, pulse-chase experiments revealed that the binding of QPD mutant homodimers remained constant as opposed to increasing, suggesting that ERdj3 does not normally undergo reiterative binding cycles with substrates. PMID:25143379

Efficacy, pharmacokinetics, and biodistribution of thermosensitive chitosan/β-glycerophosphate hydrogel loaded with docetaxel.

PubMed

Li, Cuiyun; Ren, Shuangxia; Dai, Yu; Tian, Fengjie; Wang, Xin; Zhou, Sufeng; Deng, Shuhua; Liu, Qi; Zhao, Jie; Chen, Xijing

2014-04-01

Docetaxel (DTX) is a widely used anticancer drug for various solid tumors. However, its poor solubility in water and lack of specification are two limitations for clinical use. The aim of the study was to develop a thermosensitive chitosan/β-glycerophosphate (C/GP) hydrogel loaded with DTX for intratumoral delivery. The in vitro release profiles, in vivo antitumor efficacy, pharmacokinetics, and biodistribution of DTX-loaded C/GP hydrogel (DTX-C/GP) were evaluated. The results of in vitro release study demonstrated that DTX-C/GP had the property of controlled delivery for a reasonable time span of 3 weeks and the release period was substantially affected by initial DTX strength. The antitumor efficacy of DTX-C/GP was observed at 20 mg/kg in H22 tumor-bearing mice. It was found that the tumor volume was definitely minimized by intratumoral injection of DTX-C/GP. Compared with saline group, the tumor inhibition rate of blank gel, intravenous DTX solution, intratumoral DTX solution, and DTX-C/GP was 2.3%, 29.8%, 41.9%, and 58.1%, respectively. Further, the in vivo pharmacokinetic characteristics of DTX-C/GP correlated well with the in vitro release. DTX-C/GP significantly prolonged the DTX retention and maintained a high DTX concentration in tumor. The amount of DTX distributed to the normal tissues was minimized so that the toxicity was effectively reduced. In conclusion, DTX-C/GP demonstrated controlled release and significant efficacy and exhibited potential for further clinical development.

Frictional properties of the Nankai frontal thrust explain recurring shallow slow slip events

NASA Astrophysics Data System (ADS)

Saffer, D. M.; Ikari, M.; Kopf, A.; Roesner, A.

2017-12-01

Recent observations provide evidence for shallow slip reaching to the trench on subduction megathrusts, both in earthquakes and slow slip events (SSE). This is at odds with existing friction studies, which report primarily velocity-strengthening behavior (friction increases with slip velocity) for subduction fault material and synthetic analogs, which leads only to stable sliding. We report on direct shearing experiments on fault rocks from IODP Site C0007, which sampled the frontal thrust of the Nankai accretionary prism. This fault has been implicated in both coseimic slip and recurring SSE. We focus on material from 437.2 meters below seafloor, immediately above a localized shear zone near the base of the fault. In our experiments, a 25 mm diameter cylindrical specimen is loaded in an assembly of two steel plates. After application of normal stress (3, 10, or 17 MPa) and subsequent equilibration, the lower plate is driven at a constant velocity while the upper plate remains stationary; this configuration forces shear to localize between the two plates. After reaching a steady state residual friction coefficient (µss), we conducted velocity-stepping tests to measure the friction rate parameter (a-b), defined as the change in friction for a change in velocity: (a-b) = Δuss/ln(V/Vo), over a range of velocities from 0.1-100 µm s-1. We find that µss ranges from 0.26 to 0.32 and exhibits a slight decrease with normal stress. We observe velocity-weakening behavior at low normal stresses (3-10 MPa) and for low sliding velocities (< 3-10 µm s-1). Values of (a-b)_increase systematically from -0.007 to -0.005 at velocities of 0.3-1 µm s-1, to 0.001-0.045 at velocities >30 µm s-1. At higher normal stress (17 MPa), we observe dominantly velocity-strengthening, consistent with previously reported measurements for 25 MPa normal stress. Our observation of rate weakening at slip rates matching those of SSE in the outer Nankai forearc provide a potential explanation for periodic strain accumulation and subsequent release during SSE near the trench. The observation of rate weakening behavior only at low normal stresses also suggests that nucleation of these SSE should be restricted to shallow depths (< 2-5 km) or zones of elevated pore fluid pressure.

Frictional properties of the Nankai frontal thrust explain recurring shallow slow slip events

NASA Astrophysics Data System (ADS)

Scholz, J. R.; Davy, C.; Barruol, G.; Fontaine, F. R.; Cordier, E.

2016-12-01

Recent observations provide evidence for shallow slip reaching to the trench on subduction megathrusts, both in earthquakes and slow slip events (SSE). This is at odds with existing friction studies, which report primarily velocity-strengthening behavior (friction increases with slip velocity) for subduction fault material and synthetic analogs, which leads only to stable sliding. We report on direct shearing experiments on fault rocks from IODP Site C0007, which sampled the frontal thrust of the Nankai accretionary prism. This fault has been implicated in both coseimic slip and recurring SSE. We focus on material from 437.2 meters below seafloor, immediately above a localized shear zone near the base of the fault. In our experiments, a 25 mm diameter cylindrical specimen is loaded in an assembly of two steel plates. After application of normal stress (3, 10, or 17 MPa) and subsequent equilibration, the lower plate is driven at a constant velocity while the upper plate remains stationary; this configuration forces shear to localize between the two plates. After reaching a steady state residual friction coefficient (µss), we conducted velocity-stepping tests to measure the friction rate parameter (a-b), defined as the change in friction for a change in velocity: (a-b) = Δuss/ln(V/Vo), over a range of velocities from 0.1-100 µm s-1. We find that µss ranges from 0.26 to 0.32 and exhibits a slight decrease with normal stress. We observe velocity-weakening behavior at low normal stresses (3-10 MPa) and for low sliding velocities (< 3-10 µm s-1). Values of (a-b)_increase systematically from -0.007 to -0.005 at velocities of 0.3-1 µm s-1, to 0.001-0.045 at velocities >30 µm s-1. At higher normal stress (17 MPa), we observe dominantly velocity-strengthening, consistent with previously reported measurements for 25 MPa normal stress. Our observation of rate weakening at slip rates matching those of SSE in the outer Nankai forearc provide a potential explanation for periodic strain accumulation and subsequent release during SSE near the trench. The observation of rate weakening behavior only at low normal stresses also suggests that nucleation of these SSE should be restricted to shallow depths (< 2-5 km) or zones of elevated pore fluid pressure.

Fission-gas-release rates from irradiated uranium nitride specimens

NASA Technical Reports Server (NTRS)

Weinstein, M. B.; Kirchgessner, T. A.; Tambling, T. N.

1973-01-01

Fission-gas-release rates from two 93 percent dense UN specimens were measured using a sweep gas facility. Specimen burnup rates averaged .0045 and .0032 percent/hr, and the specimen temperatures ranged from 425 to 1323 K and from 552 to 1502 K, respectively. Burnups up to 7.8 percent were achieved. Fission-gas-release rates first decreased then increased with burnup. Extensive interconnected intergranular porosity formed in the specimen operated at over 1500 K. Release rate variation with both burnup and temperature agreed with previous irradiation test results.

Effect of mean diameter and polydispersity of PLG microspheres on drug release: experiment and theory.

PubMed

Berchane, N S; Carson, K H; Rice-Ficht, A C; Andrews, M J

2007-06-07

The need to tailor release rate profiles from polymeric microspheres is a significant problem. Microsphere size, which has a significant effect on drug release rate, can potentially be varied to design a controlled drug delivery system with desired release profile. In this work the effects of microspheres mean diameter, polydispersity, and polymer degradation on drug release rate from poly(lactide-co-glycolide) (PLG) microspheres are described. Piroxicam containing PLG microspheres were fabricated at 20% loading, and at three different impeller speeds. A portion of the microspheres was then sieved giving five different size distributions. In vitro release kinetics were determined for each preparation. Based on these experimental results, a suitable mathematical theory has been developed that incorporates the effect of microsphere size distribution and polymer degradation on drug release. We show from in vitro release experiments that microsphere size has a significant effect on drug release rate. The initial release rate decreased with an increase in microsphere size. In addition, the release profile changed from first order to concave-upward (sigmoidal) as the microsphere size was increased. The mathematical model gave a good fit to the experimental release data. For highly polydisperse populations (polydispersity parameter b<3), incorporating the microsphere size distribution into the mathematical model gave a better fit to the experimental results than using the representative mean diameter. The validated mathematical model can be used to predict small-molecule drug release from PLG microsphere populations.

Percutaneous external fixator pins with bactericidal micron-thin sol-gel films for the prevention of pin tract infection.

PubMed

Qu, Haibo; Knabe, Christine; Radin, Shula; Garino, Jonathan; Ducheyne, Paul

2015-09-01

Risk of infection is considerable in open fractures, especially when fracture fixation devices are used to stabilize the fractured bones. Overall deep infection rates of 16.2% have been reported. The infection rate is even greater, up to 32.2%, with external fixation of femoral fractures. The use of percutaneous implants for certain clinical applications, such as percutaneous implants for external fracture fixation, still represents a challenge today. Currently, bone infections are very difficult to treat. Very potent antibiotics are needed, which creates the risk of irreversible damage to other organs, when the antibiotics are administered systemically. As such, controlled, local release is being pursued, but no such treatments are in clinical use. Herein, the use of bactericidal micron-thin sol-gel films on metallic fracture fixation pins is reported. The data demonstrates that triclosan (2,4,4'-trichloro-2'-hydroxydiphenylether), an antimicrobial agent, can be successfully incorporated into micron-thin sol-gel films deposited on percutaneous pins. The sol-gel films continuously release triclosan in vitro for durations exceeding 8 weeks (longest measured time point). The bactericidal effect of the micron-thin sol-gel films follows from both in vitro and in vivo studies. Inserting percutaneous pins in distal rabbit tibiae, there were no signs of infection around implants coated with a micron-thin sol-gel/triclosan film. Healing had progressed normally, bone tissue growth was normal and there was no epithelial downgrowth. This result was in contrast with the results in rabbits that received control, uncoated percutaneous pins, in which abundant signs of infection and epithelial downgrowth were observed. Thus, well-adherent, micron-thin sol-gel films laden with a bactericidal molecule successfully prevented pin tract infection. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of Quaternary Ammonium Carboxymethylchitosan on Release Rate In-vitro of Aspirin Sustained-release Matrix Tablets

PubMed Central

Meng, Lingbin; Teng, Zhongqiu; Zheng, Nannan; Meng, Weiwei; Dai, Rongji; Deng, Yulin

2013-01-01

The aim of this study was to develop a derivative of chitosan as pharmaceutical excipient used in sustained-release matrix tablets of poorly soluble drugs. A water-soluble quaternary ammonium carboxymethylchitosan was synthesized by a two-step reaction with carboxymethylchitosan (CMCTS), decylalkyl dimethyl ammonium and epichlorohydrin. The elemental analysis showed that the target product with 10.27% of the maximum grafting degree was obtained. To assess the preliminary safety of this biopolymer, cell toxicity assay was employed. In order to further investigate quaternary ammonium carboxymethylchitosan application as pharmaceutical excipient, aspirin was chosen as model drug. The effect of quaternary ammonium CMCTS on aspirin release rate from sustained-release matrix tablets was examined by in-vitro dissolution experiments. The results showed that this biopolymer had a great potential in increasing the dissolution of poorly soluble drug. With the addition of CMCTS-CEDA, the final cumulative release rate of drug rose up to 90%. After 12 h, at the grade of 10, 20 and 50 cps, the drug release rate increased from 58.1 to 90.7%, from 64.1 to 93.9%, from 69.3 to 96.1%, respectively. At the same time, aspirin release rate from sustainedrelease model was found to be related to the amount of quaternary ammonium CMCTS employed. With the increase of CMCTS-CEDA content, the accumulated release rate increased from 69.1% to 86.7%. The mechanism of aspirin release from sustained-release matrix tablets was also preliminary studied to be Fick diffusion. These data demonstrated that the chitosan derivative has positive effect on drug release from sustained-release matrix tablets. PMID:24250627

Reaerosolization of Fluidized Spores in Ventilation Systems▿

PubMed Central

Krauter, Paula; Biermann, Arthur

2007-01-01

This project examined dry, fluidized spore reaerosolization in a heating, ventilating, and air conditioning duct system. Experiments using spores of Bacillus atrophaeus, a nonpathogenic surrogate for Bacillus anthracis, were conducted to delineate the extent of spore reaerosolization behavior under normal indoor airflow conditions. Short-term (five air-volume exchanges), long-term (up to 21,000 air-volume exchanges), and cycled (on-off) reaerosolization tests were conducted using two common duct materials. Spores were released into the test apparatus in turbulent airflow (Reynolds number, 26,000). After the initial pulse of spores (approximately 1010 to 1011 viable spores) was released, high-efficiency particulate air filters were added to the air intake. Airflow was again used to perturb the spores that had previously deposited onto the duct. Resuspension rates on both steel and plastic duct materials were between 10−3 and 10−5 per second, which decreased to 10 times less than initial rates within 30 min. Pulsed flow caused an initial spike in spore resuspension concentration that rapidly decreased. The resuspension rates were greater than those predicted by resuspension models for contamination in the environment, a result attributed to surface roughness differences. There was no difference between spore reaerosolization from metal and that from plastic duct surfaces over 5 hours of constant airflow. The spores that deposited onto the duct remained a persistent source of contamination over a period of several hours. PMID:17293522

Radioimmunoassay of Human Serum Thyrotrophin

PubMed Central

Hall, Reginald; Amos, Jacqueline; Ormston, Brian J.

1971-01-01

The double antibody radioimmunoassay of serum thyroid-stimulating hormone (TSH) allows measurement of circulating levels of the hormone in most normal subjects. The serum TSH level in normal subjects is 1·6 ± 0·8μU/ml. Patients with non-toxic goitre and acromegaly have normal TSH levels. Values are always raised in hypothyroid patients (with primary thyroid disease) and are significantly lowered in those with hyperthyroidism. Of the many stimuli used in an attempt to raise TSH levels in normal adult subjects only three—synthetic thyrotrophin-releasing hormone, ethinyloestradiol, and carbimazole plus iodides—have been effective. The major clinical application of the TSH immunoassay lies in the diagnosis of minor degrees of hypothyroidism. An impaired response of serum TSH to synthetic thyrotrophin-releasing hormone should also help in the diagnosis of hypopituitarism affecting TSH production. PMID:5548300

Strain Rate Dependency of Fracture Toughness, Energy Release Rate and Geomechanical Attributes of Select Indian Shales

NASA Astrophysics Data System (ADS)

Mahanta, B.; Vishal, V.; Singh, T. N.; Ranjith, P.

2016-12-01

In addition to modern improved technology, it requires detailed understanding of rock fractures for the purpose of enhanced energy extraction through hydraulic fracturing of gas shales and geothermal energy systems. The understanding of rock fracture behavior, patterns and properties such as fracture toughness; energy release rate; strength and deformation attributes during fracturing hold significance. Environmental factors like temperature, pressure, humidity, water vapor and experimental condition such as strain rate influence the estimation of these properties. In this study, the effects of strain rates on fracture toughness, energy release rate as well as geomechanical properties like uniaxial compressive strength, Young's modulus, failure strain, tensile strength, and brittleness index of gas shales were investigated. In addition to the rock-mechanical parameters, the fracture toughness and the energy release rates were measured for three different modes viz. mode I, mixed mode (I-II) and mode II. Petrographic and X-ray diffraction (XRD) analyses were performed to identify the mineral composition of the shale samples. Scanning electron microscope (SEM) analyses were conducted to have an insight about the strain rate effects on micro-structure of the rock. The results suggest that the fracture toughness; the energy release rate as well as other geomechanical properties are a function of strain rates. At high strain rates, the strength and stiffness of shale increases which in turn increases the fracture toughness and the energy release rate of shale that may be due to stress redistribution during grain fracturing. The fracture toughness and the strain energy release rates for all the modes (I/I-II/II) are comparable at lower strain rates, but they vary considerably at higher strain rates. In all the cases, mode I and mode II fracturing requires minimum and maximum applied energy, respectively. Mode I energy release rate is maximum, compared to the other modes.

Hindered disulfide bonds to regulate release rate of model drug from mesoporous silica.

PubMed

Nadrah, Peter; Maver, Uroš; Jemec, Anita; Tišler, Tatjana; Bele, Marjan; Dražić, Goran; Benčina, Mojca; Pintar, Albin; Planinšek, Odon; Gaberšček, Miran

2013-05-01

With the advancement of drug delivery systems based on mesoporous silica nanoparticles (MSNs), a simple and efficient method regulating the drug release kinetics is needed. We developed redox-responsive release systems with three levels of hindrance around the disulfide bond. A model drug (rhodamine B dye) was loaded into MSNs' mesoporous voids. The pore opening was capped with β-cyclodextrin in order to prevent leakage of drug. Indeed, in absence of a reducing agent the systems exhibited little leakage, while the addition of dithiothreitol cleaved the disulfide bonds and enabled the release of cargo. The release rate and the amount of released dye were tuned by the level of hindrance around disulfide bonds, with the increased hindrance causing a decrease in the release rate as well as in the amount of released drug. Thus, we demonstrated the ability of the present mesoporous systems to intrinsically control the release rate and the amount of the released cargo by only minor structural variations. Furthermore, an in vivo experiment on zebrafish confirmed that the present model delivery system is nonteratogenic.

Long-suppressed ponderosa pine seedlings respond to release.

Treesearch

Walter G. Dahms

1960-01-01

Long-suppressed ponderosa pine seedlings and saplings have a remarkable ability to recover and resume normal growth when released. This fact is strikingly demonstrated by a study begun in 1934 on the Pringle Falls Experimental Forest, near Bend, Oregon.

33 CFR 208.22 - Twin Buttes Dam and Reservoir, Middle and South Concho Rivers, Tex.

Code of Federal Regulations, 2013 CFR

2013-07-01

... and releases; uncontrolled spillway releases; storage; reservoir inflow; available evaporation data.... Normally, one reading at 8 a.m. shall be shown for each day. Readings of all items except evaporation shall...

33 CFR 208.22 - Twin Buttes Dam and Reservoir, Middle and South Concho Rivers, Tex.

Code of Federal Regulations, 2014 CFR

2014-07-01

... and releases; uncontrolled spillway releases; storage; reservoir inflow; available evaporation data.... Normally, one reading at 8 a.m. shall be shown for each day. Readings of all items except evaporation shall...

33 CFR 208.22 - Twin Buttes Dam and Reservoir, Middle and South Concho Rivers, Tex.

Code of Federal Regulations, 2012 CFR

2012-07-01

... and releases; uncontrolled spillway releases; storage; reservoir inflow; available evaporation data.... Normally, one reading at 8 a.m. shall be shown for each day. Readings of all items except evaporation shall...

Release from or through a wax matrix system. I. Basic release properties of the wax matrix system.

PubMed

Yonezawa, Y; Ishida, S; Sunada, H

2001-11-01

Release properties from a wax matrix tablet was examined. To obtain basic release properties, the wax matrix tablet was prepared from a physical mixture of drug and wax powder (hydrogenated caster oil) at a fixed mixing ratio. Properties of release from the single flat-faced surface or curved side surface of the wax matrix tablet were examined. The applicability of the square-root time law and of Higuchi equations was confirmed. The release rate constant obtained as g/min(1/2) changed with the release direction. However, the release rate constant obtained as g/cm2 x min(1/2) was almost the same. Hence it was suggested that the release property was almost the same and the wax matrix structure was uniform independent of release surface or direction at a fixed mixing ratio. However, these equations could not explain the entire release process. The applicability of a semilogarithmic equation was not as good compared with the square-root time law or Higuchi equation. However, it was revealed that the semilogarithmic equation was available to simulate the entire release process, even though the fit was somewhat poor. Hence it was suggested that the semilogarithmic equation was sufficient to describe the release process. The release rate constant was varied with release direction. However, these release rate constants were expressed by a function of the effective surface area and initial amount, independent of the release direction.

PHAGE FORMATION IN STAPHYLOCOCCUS MUSCAE CULTURES

PubMed Central

Price, Winston H.

1949-01-01

1. The total nucleic acid synthesized by normal and by infected S. muscae suspensions is approximately the same. This is true for either lag phase cells or log phase cells. 2. The amount of nucleic acid synthesized per cell in normal cultures increases during the lag period and remains fairly constant during log growth. 3. The amount of nucleic acid synthesized per cell by infected cells increases during the whole course of the infection. 4. Infected cells synthesize less RNA and more DNA than normal cells. The ratio of RNA/DNA is larger in lag phase cells than in log phase cells. 5. Normal cells release neither ribonucleic acid nor desoxyribonucleic acid into the medium. 6. Infected cells release both ribonucleic acid and desoxyribonucleic acid into the medium. The time and extent of release depend upon the physiological state of the cells. 7. Infected lag phase cells may or may not show an increased RNA content. They release RNA, but not DNA, into the medium well before observable cellular lysis and before any virus is liberated. At virus liberation, the cell RNA content falls to a value below that initially present, while DNA, which increased during infection falls to approximately the original value. 8. Infected log cells show a continuous loss of cell RNA and a loss of DNA a short time after infection. At the time of virus liberation the cell RNA value is well below that initially present and the cells begin to lyse. PMID:18139006

Reconviction and revocation rates in Flanders after medium security treatment.

PubMed

Jeandarme, Inge; Habets, Petra; Oei, T I; Bogaerts, Stefan

2016-01-01

To examine the criminal outcome of Flemish forensic psychiatric patients ('internees') after medium security treatment. Also, the effect of conditional release on recidivism of two subgroups (internees under conditional release and internees who received unconditional release) was examined. Reconviction rates and revocation rates were collected for all participants. Kaplan-Meier survival analyses were used to investigate recidivism rates while controlling for time at risk. During the 10-year period, 502 offenders were discharged from medium security treatment. Over a follow-up period averaging 3.6years, 7.4% of discharged patients were reconvicted or received a new 'not guilty by reason of insanity' (NGRI) verdict for a violent offence. One-quarter of the population had their conditional release revoked. Part of the study population was granted unconditional release. Reconviction rates were higher after unconditional release in comparison to conditional release. The results of this study suggest that the court supervision of NGRI patients in Flanders is effective in protecting the community from further offending. Copyright © 2016 Elsevier Ltd. All rights reserved.

Development of extended release dosage forms using non-uniform drug distribution techniques.

PubMed

Huang, Kuo-Kuang; Wang, Da-Peng; Meng, Chung-Ling

2002-05-01

Development of an extended release oral dosage form for nifedipine using the non-uniform drug distribution matrix method was conducted. The process conducted in a fluid bed processing unit was optimized by controlling the concentration gradient of nifedipine in the coating solution and the spray rate applied to the non-pareil beads. The concentration of nifedipine in the coating was controlled by instantaneous dilutions of coating solution with polymer dispersion transported from another reservoir into the coating solution at a controlled rate. The USP dissolution method equipped with paddles at 100 rpm in 0.1 N hydrochloric acid solution maintained at 37 degrees C was used for the evaluation of release rate characteristics. Results indicated that (1) an increase in the ethyl cellulose content in the coated beads decreased the nifedipine release rate, (2) incorporation of water-soluble sucrose into the formulation increased the release rate of nifedipine, and (3) adjustment of the spray coating solution and the transport rate of polymer dispersion could achieve a dosage form with a zero-order release rate. Since zero-order release rate and constant plasma concentration were achieved in this study using the non-uniform drug distribution technique, further studies to determine in vivo/in vitro correlation with various non-uniform drug distribution dosage forms will be conducted.

Interaction between fed gastric media (Ensure Plus®) and different hypromellose based caffeine controlled release tablets: comparison and mechanistic study of caffeine release in fed and fasted media versus water using the USP dissolution apparatus 3.

PubMed

Franek, Frans; Holm, Per; Larsen, Frank; Steffansen, Bente

2014-01-30

The aim of the study was to investigate caffeine release in fed and fasted state media from three controlled release matrix tablets containing different HPMC viscosity grades. The biorelevant in vitro dissolution methods utilize the USP 3 dissolution apparatus and biorelevant media to simulate fed and fasted gastro-intestinal dissolution conditions. The effect of tablet reciprocation rate (dip speed) in dissolution media (10 and 15 dips per minute) and media (water, fed and fasted) on caffeine release rate from - and erosion rate of - 100, 4000 and 15,000 mPa s HPMC viscosity tablets was investigated using factorial designed experiments. Furthermore, the mechanism of release in Ensure Plus(®), a nutrition drink similar in composition to the FDA standard meal, was investigated by studying tablet swelling using texture analysis. Altering dip speed has negligible effect on release and erosion rates. Using fasted media instead of water slightly decreases caffeine release from 100 and 4000 mPa s HPMC viscosity tablets as well as erosion rates, while 15,000 mPa s tablets remain unaffected. Fed compared to fasted media decreases caffeine release rate, and the food effect is greater for the 100 mPa s viscosity tablets compared to the 4000 and 15,000 mPa s viscosity tablets. The investigation using texture analysis indicates that Ensure Plus(®) becomes rate-limiting for caffeine release from HPMC tablets by forming a hydrophobic barrier around the tablets. The barrier decreases tablet water permeation, which decreases erosion rate in 100 mPa s viscosity tablets, swelling in 15,000 mPa s viscosity tablets and caffeine release from both tablets. This observed interaction between Ensure Plus(®) and the HPMC tablets may translate into decreased drug release rate in the fed stomach, which may decrease the amount of drug available for absorption in the small intestine and thus reduce systemic drug exposure and maximum plasma concentration. Copyright © 2013 Elsevier B.V. All rights reserved.

Piezo1 regulates mechanotransductive release of ATP from human RBCs.

PubMed

Cinar, Eyup; Zhou, Sitong; DeCourcey, James; Wang, Yixuan; Waugh, Richard E; Wan, Jiandi

2015-09-22

Piezo proteins (Piezo1 and Piezo2) are recently identified mechanically activated cation channels in eukaryotic cells and associated with physiological responses to touch, pressure, and stretch. In particular, human RBCs express Piezo1 on their membranes, and mutations of Piezo1 have been linked to hereditary xerocytosis. To date, however, physiological functions of Piezo1 on normal RBCs remain poorly understood. Here, we show that Piezo1 regulates mechanotransductive release of ATP from human RBCs by controlling the shear-induced calcium (Ca(2+)) influx. We find that, in human RBCs treated with Piezo1 inhibitors or having mutant Piezo1 channels, the amounts of shear-induced ATP release and Ca(2+) influx decrease significantly. Remarkably, a critical extracellular Ca(2+) concentration is required to trigger significant ATP release, but membrane-associated ATP pools in RBCs also contribute to the release of ATP. Our results show how Piezo1 channels are likely to function in normal RBCs and suggest a previously unidentified mechanotransductive pathway in ATP release. Thus, we anticipate that the study will impact broadly on the research of red cells, cellular mechanosensing, and clinical studies related to red cell disorders and vascular disease.

[Anthology of the first clinical studies with hypothalamic hormones: a story of successful international cooperation].

PubMed

Schally, Andrew V; Gual, Carlos

2002-01-01

Our early pioneering clinical trials in Mexico with natural and synthetic thyrotropin-releasing hormone (TRH) and luteinizing hormone releasing hormone (LH-RH) also known as gonadotropin releasing hormone (Gn-RH), were reviewed. Highly purified TRH of porcine origin was shown to stimulate Thyrotropin (TSH) release in hypothyroid cretins. Subsequent tests with synthetic TRH also demonstrated significant increases in plasma TSH in normal men and women as well as in patients with primary hypothyroidism and other endocrine disorders. Even more extensive clinical studies were carried out with highly purified natural porcine LH-RH. Subjects with normal basal serum levels of gonadotropins, low levels (men and women pretreated with steroids) and high levels (e.g. post menopausal women) all responded to LH-RH with a release of LH and FSH. The results of these early studies with the natural LH-RH were confirmed by the use of synthetic LH-RH. These investigations made in Mexico with TRH and LH-RH preceded all other clinical studies by a wide margin. Subsequently various clinical investigations with LH-RH agonists and antagonists were also carried out. All these studies played a major role in introducing hypothalamic-releasing hormones into clinical medicine.

Emission rates of sulfur dioxide and carbon dioxide from Redoubt Volcano, Alaska during the 1989-1990 eruptions

USGS Publications Warehouse

Casadevall, T.J.; Doukas, M.P.; Neal, C.A.; McGimsey, R.G.; Gardner, C.A.

1994-01-01

Airborne measurements of sulfur dioxide emission rates in the gas plume emitted from fumaroles in the summit crater of Redoubt Volcano were started on March 20, 1990 using the COSPEC method. During the latter half of the period of intermittent dome growth and destruction, between March 20 and mid-June 1990, sulfur dioxide emission rates ranged from approximately 1250 to 5850 t/d, rates notably higher than for other convergent-plate boundary volcanoes during periods of active dome growth. Emission rates following the end of dome growth from late June 1990 through May 1991 decreased steadily to less than 75 t/d. The largest mass of sulfur dioxide was released during the period of explosive vent clearing when explosive degassing on December 14-15 injected at least 175,000 ?? 50,000 tonnes of SO2 into the atmosphere. Following the explosive eruptions of December 1989, Redoubt Volcano entered a period of intermittent dome growth from late December 1989 to mid-June 1990 during which Redoubt emitted a total mass of SO2 ranging from 572,000 ?? 90,000 tonnes to 680,000 ?? 90,000 tonnes. From mid-June 1990 through May 1991, the volcano was in a state of posteruption degassing into the troposphere, producing approximately 183,000 ?? 50,000 tonnes of SO2. We estimate that Redoubt Volcano released a minimum mass of sulfur dioxide of approximately 930,000 tonnes. While COSPEC data were not obtained frequently enough to enable their use in eruption prediction, SO2 emission rates clearly indicated a consistent decline in emission rates between March through October 1990 and a continued low level of emission rates through the first half of 1991. Values from consecutive daily measurements of sulfur dioxide emission rates spanning the March 23, 1990 eruption decreased in the three days prior to eruption. That decrease was coincident with a several-fold increase in the frequency of shallow seismic events, suggesting partial sealing of the magma conduit to gas loss that resulted in pressurization of the shallow magma system and an increase in earthquake activity. Unlike the short-term SO2 decrease in March 1990, the long-term decrease of sulfur dioxide emission rates from March 1990 through May 1991 was coincident with low rates of seismic energy release and was interpreted to reflect gradual depressurization of the shallow magma reservoir. The long-term declines in seismic energy release and in SO2 emission rates led AVO scientists to conclude on April 19, 1991 that the potential for further eruptive activity from Redoubt Volcano had diminished, and on this basis, the level of concern color code for the volcano was changed from code yellow (Volcano is restless; earthquake activity is elevated; activity may include extrusion of lava) to code green (Volcano is in its normal 'dormant' state). ?? 1994.

Residual thermal and moisture influences on the strain energy release rate analysis of edge delamination

NASA Technical Reports Server (NTRS)

Obrien, T. K.; Raju, I. S.; Garber, D. P.

1985-01-01

A laminated plate theory analysis is developed to calculate the strain energy release rate associated with edge delamination growth in a composite laminate. The analysis includes the contribution of residual thermal and moisture stresses to the strain energy released. The strain energy release rate, G, increased when residual thermal effects were combined with applied mechanical strains, but then decreased when increasing moisture content was included. A quasi-three-dimensional finite element analysis indicated identical trends and demonstrated these same trends for the individual strain energy release rate components, G sub I and G sub II, associated with interlaminar tension and shear. An experimental study indicated that for T300/5208 graphite-epoxy composites, the inclusion of residual thermal and moisture stresses did not significantly alter the calculation of interlaminar fracture toughness from strain energy release rate analysis of edge delamination data taken at room temperature, ambient conditions.

Quantification of Energy Release in Composite Structures

NASA Technical Reports Server (NTRS)

Minnetyan, Levon

2003-01-01

Energy release rate is usually suggested as a quantifier for assessing structural damage tolerance. Computational prediction of energy release rate is based on composite mechanics with micro-stress level damage assessment, finite element structural analysis and damage progression tracking modules. This report examines several issues associated with energy release rates in composite structures as follows: Chapter I demonstrates computational simulation of an adhesively bonded composite joint and validates the computed energy release rates by comparison with acoustic emission signals in the overall sense. Chapter II investigates the effect of crack plane orientation with respect to fiber direction on the energy release rates. Chapter III quantifies the effects of contiguous constraint plies on the residual stiffness of a 90 ply subjected to transverse tensile fractures. Chapter IV compares ICAN and ICAN/JAVA solutions of composites. Chapter V examines the effects of composite structural geometry and boundary conditions on damage progression characteristics.

Quantification of Energy Release in Composite Structures

NASA Technical Reports Server (NTRS)

Minnetyan, Levon; Chamis, Christos C. (Technical Monitor)

2003-01-01

Energy release rate is usually suggested as a quantifier for assessing structural damage tolerance. Computational prediction of energy release rate is based on composite mechanics with micro-stress level damage assessment, finite element structural analysis and damage progression tracking modules. This report examines several issues associated with energy release rates in composite structures as follows: Chapter I demonstrates computational simulation of an adhesively bonded composite joint and validates the computed energy release rates by comparison with acoustic emission signals in the overall sense. Chapter II investigates the effect of crack plane orientation with respect to fiber direction on the energy release rates. Chapter III quantifies the effects of contiguous constraint plies on the residual stiffness of a 90 deg ply subjected to transverse tensile fractures. Chapter IV compares ICAN and ICAN/JAVA solutions of composites. Chapter V examines the effects of composite structural geometry and boundary conditions on damage progression characteristics.

Release of bioactive peptides from polyurethane films in vitro and in vivo: Effect of polymer composition.

PubMed

Zhang, Jing; Woodruff, Trent M; Clark, Richard J; Martin, Darren J; Minchin, Rodney F

2016-09-01

Thermoplastic polyurethanes (TPUs) are widely used in biomedical applications due to their excellent biocompatibility. Their role as matrices for the delivery of small molecule therapeutics has been widely reported. However, very little is known about the release of bioactive peptides from this class of polymers. Here, we report the release of linear and cyclic peptides from TPUs with different hard and soft segments. Solvent casting of the TPU at room temperature mixed with the different peptides resulted in reproducible efflux profiles with no evidence of drug degradation. Peptide release was dependent on the size as well as the composition of the TPU. Tecoflex 80A (T80A) showed more extensive release than ElastEon 5-325, which correlated with a degree of hydration. It was also shown that the composition of the medium influenced the rate and extent of peptide efflux. Blending the different TPUs allowed for better control of peptide efflux, especially the initial burst effect. Peptide-loaded TPU prolonged the plasma levels of the anti-inflammatory cyclic peptide PMX53, which normally has a plasma half-life of less than 30min. Using a blend of T80A and E5-325, therapeutic plasma levels of PMX53 were observed up to 9days following a single intraperitoneal implantation of the drug-loaded film. PMX53 released from the blended TPUs significantly inhibited B16-F10 melanoma tumor growth in mice demonstrating its bioactivity in vivo. This study provides important findings for TPU-based therapeutic peptide delivery that could improve the pharmacological utility of peptides as therapeutics. Therapeutic peptides can be highly specific and potent pharmacological agents, but are poorly absorbed and rapidly degraded in the body. This can be overcome by using a matrix that protects the peptide in vivo and promotes its slow release so that a therapeutic effect can be achieved over days or weeks. Thermoplastic polyurethanes are a versatile family of polymers that are biocompatible and used for medical implants. Here, the release of several peptides from a range of polyurethanes was shown to depend on the type of polymer used in the polyurethane. This is the first study to examine polyurethane blends for peptide delivery and shows that the rate and extent of peptide release can be fine-tuned using different hard and soft segment mixtures in the polymer. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Incorporation of Levodopa into Biopolymer Coatings Based on Carboxylated Carbon Nanotubes for pH-Dependent Sustained Release Drug Delivery.

PubMed

Tan, Julia Meihua; Saifullah, Bullo; Kura, Aminu Umar; Fakurazi, Sharida; Hussein, Mohd Zobir

2018-05-31

Four drug delivery systems were formulated by non-covalent functionalization of carboxylated single walled carbon nanotubes using biocompatible polymers as coating agent (i.e., Tween 20, Tween 80, chitosan or polyethylene glycol) for the delivery of levodopa, a drug used in Parkinson's disease. The chemical interaction between the coating agent and carbon nanotubes-levodopa conjugate was confirmed by Fourier transform infrared (FTIR) and Raman studies. The drug release profiles were revealed to be dependent upon the type of applied coating material and this could be further adjusted to a desired rate to meet different biomedical conditions. In vitro drug release experiments measured using UV-Vis spectrometry demonstrated that the coated conjugates yielded a more prolonged and sustained release pattern compared to the uncoated conjugate. Cytotoxicity of the formulated conjugates was studied by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay using normal mouse embryonic fibroblast 3T3 cell line. Compared to the non-coated conjugate, the MTT data indicated that the coating procedure improved the biocompatibility of all systems by 34⁻41% when the concentration used exceeded 100 μg/mL. In conclusion, the comprehensive results of this study suggest that carbon nanotubes-based drug carrier coated with a suitable biomaterial may possibly be a potential nanoparticle system that could facilitate drug delivery to the brain with tunable physicochemical properties.

Controlling the Release of Indomethacin from Glass Solutions Layered with a Rate Controlling Membrane Using Fluid-Bed Processing. Part 2: The Influence of Formulation Parameters on Drug Release.

PubMed

Dereymaker, Aswin; Pelgrims, Jirka; Engelen, Frederik; Adriaensens, Peter; Van den Mooter, Guy

2017-04-03

This study aimed to investigate the pharmaceutical performance of an indomethacin-polyvinylpyrrolidone (PVP) glass solution applied using fluid bed processing as a layer on inert sucrose spheres and subsequently top-coated with a release rate controlling membrane consisting of either ethyl cellulose or Eudragit RL. The implications of the addition of a pore former (PVP) and the coating medium (ethanol or water) on the diffusion and release behavior were also considered. In addition, the role of a charge interaction between drug and controlled release polymer on the release was investigated. Diffusion experiments pointed to the influence of pore former concentration, rate controlling polymer type, and coating solvent on the permeability of the controlled release membranes. This can be translated to drug release tests, which show the potential of diffusion tests as a preliminary screening test and that diffusion is the main factor influencing release. Drug release tests also showed the effect of coating layer thickness. A charge interaction between INDO and ERL was demonstrated, but this had no negative effect on drug release. The higher diffusion and release observed in ERL-based rate controlling membranes was explained by a higher hydrophilicity, compared to EC.

Effects of preheated combustion air on laminar coflow diffusion flames under normal and microgravity conditions

NASA Astrophysics Data System (ADS)

Ghaderi Yeganeh, Mohammad

Global energy consumption has been increasing around the world, owing to the rapid growth of industrialization and improvements in the standard of living. As a result, more carbon dioxide and nitrogen oxide are being released into the environment. Therefore, techniques for achieving combustion at reduced carbon dioxide and nitric oxide emission levels have drawn increased attention. Combustion with a highly preheated air and low-oxygen concentration has been shown to provide significant energy savings, reduce pollution and equipment size, and uniform thermal characteristics within the combustion chamber. However, the fundamental understanding of this technique is limited. The motivation of the present study is to identify the effects of preheated combustion air on laminar coflow diffusion flames. Combustion characteristics of laminar coflow diffusion flames are evaluated for the effects of preheated combustion air temperature under normal and low-gravity conditions. Experimental measurements are conducted using direct flame photography, particle image velocimetry (PIV) and optical emission spectroscopy diagnostics. Laminar coflow diffusion flames are examined under four experimental conditions: normal-temperature/normal-gravity (case I), preheated-temperature/normal gravity (case II), normal-temperature/low-gravity (case III), and preheated-temperature/low-gravity (case IV). Comparisons between these four cases yield significant insights. In our studies, increasing the combustion air temperature by 400 K (from 300 K to 700 K), causes a 37.1% reduction in the flame length and about a 25% increase in peak flame temperature. The results also show that a 400 K increase in the preheated air temperature increases CH concentration of the flame by about 83.3% (CH is a marker for the rate of chemical reaction), and also increases the C2 concentration by about 60% (C2 is a marker for the soot precursor). It can therefore be concluded that preheating the combustion air increases the energy release intensity, flame temperature, C2 concentration, and, presumably, NOx production. Our work is the first to consider preheated temperature/low-gravity combustion. The results of our experiments reveal new insights. Where as increasing the temperature of the combustion air reduces the laminar flame width under normal gravity, we find that, in a low-gravity environment, increasing the combustion air temperature causes a significant increase in the flame width.

77 FR 47918 - Information Collection Activities (Released Rates)

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-10

... decision in Released Rates of Motor Common Carriers of Household Goods, Docket No. RR 999 (Amendment No. 5... loss or damage that occurs during interstate household-good moves. See Safe, Accountable, Flexible... elects anything other than full-value protection. See Released Rates of Motor Common Carriers of...

Enhancement of frequency domain indices of heart rate variability by cholinergic stimulation with pyridostigmine bromide.

PubMed

Zarei, Ali Asghar; Foroutan, Seyyed Abbas; Foroutan, Seyyed Mohsen; Erfanian Omidvar, Abbas

2011-01-01

Pyridostigmine bromide (PB) is a reversible cholinesterase inhibitor. The aim of this study was to determine the effect of orally administration of single dose sustained-released tablet of pyridostigmine bromide (PBSR) on the frequency domain indices of heart rate variability (HRV). Thirty-two healthy young men were participated in this study. They were divided into 2 groups; the pyridostigmine group (n = 22) and the placebo group (n = 10). Electrocardiogram (ECG) was recorded at 10, 30, 60, 90, 120, 150, 180, 210, 240, 300 and 420 min after PBSR administration. At each time, simultaneously, a blood sample was prepared and PB plasma concentration was measured by high-performance liquid chromatography (HPLC) method. Statistical analysis showed that in different indices of HRV, there is a significant increase in low frequency (LF) band at 300 min, but no difference in high frequency band (HF). It also showed significant decreases in normalized high frequency band (Hfnu), normalized low frequency band (Lfnu) and LF/HF ratio at 120, 240 and 300 min after PBSR administration. Maximum plasma concentration of PB was 150 min after the administration. In conclusion, administration of a single dose PBSR can enhance the frequency domains indices of HRV and improvesympathovagal balance.

Targeted transplantation of mitochondria to hepatocytes

PubMed Central

Gupta, Nidhi; Wu, Catherine H; Wu, George Y

2016-01-01

Background Mitochondrial defects in hepatocytes can result in liver dysfunction and death. Hepatocytes have cell-surface asialoglycoprotein receptors (AsGRs) which internalize AsGs within endosomes. The aim of this study was to determine whether mitochondria could be targeted to hepatocytes by AsGR-mediated endocytosis. Materials and methods An AsG, AsOR, was linked to polylysine to create a conjugate, AsOR-PL, and complexed with healthy and functional mitochondria (defined by normal morphology, cytochrome c assays, and oxygen-consumption rates). Huh7 (AsGR+) and SK Hep1 (AsGR−) cells were treated with a mitochondrial toxin to form Huh7-Mito− and SK Hep1-Mito− cells, lacking detectable mitochondrial DNA. An endosomolytic peptide, LLO, was coupled to AsOR to form AsOR-LLO. A lysosomal inhibitor, amantadine, was used in mitochondria-uptake studies as a control for nonspecific endosomal release. Results Coincubation of complexed mitochondria and AsOR-LLO with Huh7-Mito− cells increased mitochondrial DNA to >9,700-fold over control at 7 days (P<0.001), and increased mitochondrial oxygen-consumption rates to >90% of control by 10 days. Conclusion Rescue of mitochondria-damaged hepatocytes can be achieved by targeted uptake of normal mitochondria through receptor-mediated endocytosis. PMID:27942238

Influences of the Darrieus-Landau instability on premixed turbulent flames

NASA Astrophysics Data System (ADS)

Patyal, Advitya; Matalon, Moshe

2017-11-01

The propagation of turbulent flames in three-dimensional turbulent flows is studied within the context of the hydrodynamic theory. The flame is treated as a surface of density discontinuity with the flow modified by gas expansion resulting from heat released during combustion. The flame is tracked using a level-set method with a propagation speed that depends on the local flame stretch, modulated by a Markstein length. Impact of the Darrieus-Landau instability on the topology of the flame surface is studied. It is shown that similar to passive interfaces, flames under the influence of the hydrodynamic instability resort to cylindrical structures with increasing turbulence intensity, even in 3D. The mechanism of modification of vortical structures in the burned gas is identified in terms of the alignments between the vorticity vector, flame surface normal and eigenvectors of the strain rate tensor. The results indicate that the strain rate tensor is intricately coupled with the normal to the flame surface and creates anisotropy in the orientation of vortical structures, which begins to weaken as the turbulent intensity increases. Furthermore, vorticity budgets are used to highlight the relative importance of baroclinic torque due to Darrieus-Landau instability.

[Phosphorus removal characteristics by aerobic granules in normal molasses wastewater after anaerobic treatment].

PubMed

Wang, Shuo; Yu, Shui-Li; Shi, Wen-Xin; Bao, Rui-Ling; Yi, Xue-Song; Li, Jian-Zheng

2012-04-01

COD decreased obviously in normal molasses wastewater after anaerobic treatment, however, concentrations of nitrogen and phosphorus were still higher in the effluent which seriously damaged the ecological balance. In this study, aerobic granules cultivated in sequencing batch airlift reactor (SBAR) were carried out for treating the effluent; phosphorus removal processes and characteristics were discussed as well. The mean diameter of aerobic granules cultivated by multiple carbon sources (acetate, propionate and butyrate) was 1.7 mm. The average phosphorus removal efficiency was 90.9% and the level of phosphorus in effluent was only 1.3 mg x L(-1); TP released per COD consumed was 0.571 and the specific rate of TP released was 5.73 mg x (g x h)(-1). NO3(-) -N usage of phosphorus accumulating organisms (PAOs) improved during denitrifying process because the concentration of propionate and butyrate increased in multiple carbon sources which means the phosphorus uptake efficiency increased when per NO3(-) -N consumed. Phosphorus content represented a stronger correlation with magnesium, calcium and ferrum contents in aerobic granules and their extracellular polymeric substances (EPS), the phosphorus adsorption by EPS could enhance phosphorus removal. 61.9% of phosphorus accumulating organisms were denitrifying phosphorus accumulating organisms in aerobic granules and TP uptake per NO3(-) -N consumed was 1.14 which was higher than that of aerobic granules only cultivated by acetate.

[Response of vasopressin and tyrosine hydroxylase expressing neurons of the rat supraoptic nucleus to chronic osmotic stimulation].

PubMed

Abramova, M A; Calas, A; Maiily, P; Thibault, J; Ugriumov, M V

1999-06-01

This study has evaluated the dynamic of intracellular vasopressin and tyrosine hydroxylase contents in the neuron cell bodies in the supraoptic nucleus and in the axons of the posterior lobe in rats drinking 2% NaCl for 1, 2, and 3 weeks. The number of vasopressin-immunoreactive neurons increased by the end of the second week of osmotic stimulation that might be explained by the onset of vasopressin synthesis in the neurons which do not synthesize this neurohormone under normal physiological conditions. The concentration of vasopressin fell down continuously during the first two weeks of salt-loading, apparently, due to predominance of the vasopressin release over its synthesis. Over the third week of salt-loading, the intracellular concentration of vasopressin was not changed significantly suggesting the establishment of the dynamic equilibrium between the vasopressin synthesis and release. The number of tyrosine hydroxylase-immunoreactive neurons and the amount of tyrosine hydroxylase in cell bodies and the large axonal swellings, Herring bodies, increased gradually showing that the rate of tyrosine hydroxylase synthesis prevailed over that of its enzymatic degradation. Thus, the chronic stimulation of vasopressin neurons is accompanied by a number of the adaptive reactions; the most important is related to the onset of vasopressin and tyrosine hydroxylase synthesis in the neurons which do not synthetize both of them under normal conditions.

Restitution of defective glucose-stimulated insulin secretion in diabetic GK rat by acetylcholine uncovers paradoxical stimulatory effect of beta-cell muscarinic receptor activation on cAMP production.

PubMed

Dolz, Manuel; Bailbé, Danielle; Giroix, Marie-Hélène; Calderari, Sophie; Gangnerau, Marie-Noelle; Serradas, Patricia; Rickenbach, Katharina; Irminger, Jean-Claude; Portha, Bernard

2005-11-01

Because acetylcholine (ACh) is a recognized potentiator of glucose-stimulated insulin release in the normal beta-cell, we have studied ACh's effect on islets of the Goto-Kakizaki (GK) rat, a spontaneous model of type 2 diabetes. We first verified that ACh was able to restore the insulin secretory glucose competence of the GK beta-cell. Then, we demonstrated that in GK islets 1) ACh elicited a first-phase insulin release at low glucose, whereas it had no effect in Wistar; 2) total phospholipase C activity, ACh-induced inositol phosphate production, and intracellular free calcium concentration ([Ca2+]i) elevation were normal; 3) ACh triggered insulin release, even in the presence of thapsigargin, which induced a reduction of the ACh-induced [Ca2+]i response (suggesting that ACh produces amplification signals that augment the efficacy of elevated [Ca2+]i on GK exocytosis); 4) inhibition of protein kinase C did not affect [Ca2+]i nor the insulin release responses to ACh; and 5) inhibition of cAMP-dependent protein kinases (PKAs), adenylyl cyclases, or cAMP generation, while not affecting the [Ca2+]i response, significantly lowered the insulinotropic response to ACh (at low and high glucose). In conclusion, ACh acts mainly through activation of the cAMP/PKA pathway to potently enhance Ca2+-stimulated insulin release in the GK beta-cell and, in doing so, normalizes its defective glucose responsiveness.

Measurement of semiochemical release rates with a dedicated environmental control system

Treesearch

Heping Zhu; Harold W. Thistle; Christopher M. Ranger; Hongping Zhou; Brian L. Strom

2015-01-01

Insect semiochemical dispensers are commonly deployed under variable environmental conditions over a specified period. Predictions of their longevity are hampered by a lack of methods to accurately monitor and predict how primary variables affect semiochemical release rate. A system was constructed to precisely determine semiochemical release rates under...

Miniature bulge test and energy release rate in HIPed aluminum/aluminum interfacial fracture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, C.; Lovato, M. L.; Clarke, K. D.

We summarize the development of a technique of using miniature bulge test combined with three-dimensional digital image correlation (3D-DIC) for measuring energy release rate or fracture toughness of bimaterial interface of thin metal foils. Furthermore, the energy release rate associated with the HIPed aluminum/aluminum interfacial delamination is determined experimentally using the proposed technique. Detailed discussions of the schemes of preparing and conducting the bulge test, and computing various quantities required for the determination of the energy release rate are presented.

Miniature bulge test and energy release rate in HIPed aluminum/aluminum interfacial fracture

DOE PAGES

Liu, C.; Lovato, M. L.; Clarke, K. D.; ...

2017-10-13

We summarize the development of a technique of using miniature bulge test combined with three-dimensional digital image correlation (3D-DIC) for measuring energy release rate or fracture toughness of bimaterial interface of thin metal foils. Furthermore, the energy release rate associated with the HIPed aluminum/aluminum interfacial delamination is determined experimentally using the proposed technique. Detailed discussions of the schemes of preparing and conducting the bulge test, and computing various quantities required for the determination of the energy release rate are presented.

Rates of zinc and trace metal release from dissolving sphalerite at pH 2.0-4.0

USGS Publications Warehouse

Stanton, M.R.; Gemery-Hill, P. A.; Shanks, Wayne C.; Taylor, C.D.

2008-01-01

High-Fe and low-Fe sphalerite samples were reacted under controlled pH conditions to determine nonoxidative rates of release of Zn and trace metals from the solid-phase. The release (solubilization) of trace metals from dissolving sphalerite to the aqueous phase can be characterized by a kinetic distribution coefficient, (Dtr), which is defined as [(Rtr/X(tr)Sph)/(RZn/X(Zn) Sph)], where R is the trace metal or Zn release rate, and X is the mole fraction of the trace metal or Zn in sphalerite. This coefficient describes the relationship of the sphalerite dissolution rate to the trace metal mole fraction in the solid and its aqueous concentration. The distribution was used to determine some controls on metal release during the dissolution of sphalerite. Departures from the ideal Dtr of 1.0 suggest that some trace metals may be released via different pathways or that other processes (e.g., adsorption, solubility of trace minerals such as galena) affect the observed concentration of metals. Nonoxidative sphalerite dissolution (mediated by H+) is characterized by a "fast" stage in the first 24-30 h, followed by a "slow" stage for the remainder of the reaction. Over the pH range 2.0-4.0, and for similar extent of reaction (reaction time), sphalerite composition, and surface area, the rates of release of Zn, Fe, Cd, Cu, Mn and Pb from sphalerite generally increase with lower pH. Zinc and Fe exhibit the fastest rates of release, Mn and Pb have intermediate rates of release, and Cd and Cu show the slowest rates of release. The largest variations in metal release rates occur at pH 2.0. At pH 3.0 and 4.0, release rates show less variation and appear less dependent on the metal abundance in the solid. For the same extent of reaction (100 h), rates of Zn release range from 1.53 ?? 10-11 to 5.72 ?? 10-10 mol/m2/s; for Fe, the range is from 4.59 ?? 10-13 to 1.99 ?? 10-10 mol/m2/s. Trace metal release rates are generally 1-5 orders of magnitude slower than the Zn or Fe rates. Results indicate that the distributions of Fe and Cd are directly related to the rate of sphalerite dissolution throughout the reaction at pH 3.0 and 4.0 because these two elements substitute readily into sphalerite. These two metals are likely to be more amenable to usage in predictive acid dissolution models because of this behavior. The Pb distribution shows no strong relation to sphalerite dissolution and appears to be controlled by pH-dependent solubility, most likely related to trace amounts of galena. The distribution of Cu is similar to that of Fe but is the most-dependent of all metals on its mole fraction ratio (Zn:Cu) in sphalerite. The Mn distributions suggest an increase in the rate of Mn release relative to sphalerite dissolution occurs in low Mn samples as pH increases. The Mn distribution in high Mn samples is nearly independent of pH and sphalerite dissolution at pH 2.0 but shows a dependence on these two parameters at higher pH (3.0-4.0).

Characteristics of CO2 release from forest soil in the mountains near Beijing.

PubMed

Sun, Xiang Yang; Gao, Cheng Da; Zhang, Lin; Li, Su Yan; Qiao, Yong

2011-04-01

CO2 release from forest soil is a key driver of carbon cycling between the soil and atmosphere ecosystem. The rate of CO2 released from soil was measured in three forest stands (in the mountainous region near Beijing, China) by the alkaline absorption method from 2004 to 2006. The rate of CO2 released did not differ among the three stands. The CO2 release rate ranged from - 341 to 1,193 mg m(-2) h(-1), and the mean value over all three forests and sampling times was 286 mg m(-2) h(-1). CO2 release was positively correlated with soil water content and the soil temperature. Diurnally, CO2 release was higher in the day than at night. Seasonally, CO2 release was highest in early autumn and lowest in winter; in winter, negative values of CO2 release suggested that CO2 was absorbed by soil.

Characterizing the 2016 Perseid Meteor Shower Outburst

NASA Technical Reports Server (NTRS)

Blaauw, R. C.; Moser, D. E.; Molau, S.; Schult, C.; Stober, G.

2017-01-01

The Perseid meteor shower has been observed for millennia and is known for its visually spectacular meteors and occasional outbursts. Normal activity displays Zenithal Hourly Rates (ZHRs) of approximately100. The Perseids were expected to outburst in 2016, primarily due to particles released during the 1862 and 1479 revolutions of parent Comet Swift-Tuttle. NASA's Meteoroid Environment Office predicted the timing, strength and duration of the outburst for spacecraft risk using the MSFC Meteoroid Stream Model [1]. A double peak was predicted, with an outburst displaying a ZHR of 210 +/- 50 at 00:30 UTC Aug 12 (139.5deg Solar Longitude), and a traditional peak 12 hours later with rates still heightened from the outburst [2]. Video, visual, and radar observations taken worldwide by various entities were used to characterize the shower and compare to predictions.

The suitability of ultrafine coal as an industrial boiler fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barratt, D.J.; Roberts, P.T.

1989-07-01

Coal that was finely ground to a mean particle size of 12 /mu/m produced a hotter, shorter flame compared to normal pulverized fuel in a pilot scale combustor. Measurements indicated that, should this fuel be fired in an industrial boiler, the rate of ash deposition on the walls and convection tubes could be low, but that the thin ash deposits that were produced might be more highly insulating and would therefore require more frequent cleaning. A mathematical model, using reactivity and pyrolysis data measured in laboratory-scale apparatus, has been used to predict the heat release rate within a boiler. Thismore » would be sufficiently high to allow a premium-quality finely ground coal to be burned in many boilers originally designed for oil firing, provided that burner mixing patterns were optimized.« less

Setting accelerated dissolution test for PLGA microspheres containing peptide, investigation of critical parameters affecting drug release rate and mechanism.

PubMed

Tomic, I; Vidis-Millward, A; Mueller-Zsigmondy, M; Cardot, J-M

2016-05-30

The objective of this study was development of accelerated in vitro release method for peptide loaded PLGA microspheres using flow-through apparatus and assessment of the effect of dissolution parameters (pH, temperature, medium composition) on drug release rate and mechanism. Accelerated release conditions were set as pH 2 and 45°C, in phosphate buffer saline (PBS) 0.02M. When the pH was changed from 2 to 4, diffusion controlled phases (burst and lag) were not affected, while release rate during erosion phase decreased two-fold due to slower ester bonds hydrolyses. Decreasing temperature from 45°C to 40°C, release rate showed three-fold deceleration without significant change in release mechanism. Effect of medium composition on drug release was tested in PBS 0.01M (200 mOsm/kg) and PBS 0.01M with glucose (380 mOsm/kg). Buffer concentration significantly affected drug release rate and mechanism due to the change in osmotic pressure, while ionic strength did not have any effect on peptide release. Furthermore, dialysis sac and sample-and-separate techniques were used, in order to evaluate significance of dissolution technique choice on the release process. After fitting obtained data to different mathematical models, flow-through method was confirmed as the most appropriate for accelerated in vitro dissolution testing for a given formulation. Copyright © 2016 Elsevier B.V. All rights reserved.

Diffusion of progestogens through Silastic rubber implants.

PubMed

Lifchez, A S; Scommegna, A

1970-05-01

Silastic rubber capsules in 2 thicknesses (.42 mm and .80 mm) and 3 lengths (9, 14, and 19 mm) were filled with progesterone, Provera, Norgestrel, or chlormadinone acetate and implanted under the skin of rats, and the amount of steroid released was measured after 1, 2, 4, and 8 weeks. The amount of steroid released was also measured from progesterone-filled capsules .42 mm thick and varying from 19-32 mm long inserted in the uterus of 16 women volunteers for 1-7 days. The rate of release of each steroid in the rats was found to be proportionate to the length of the capsule and related, but not proportional to the thickness of the capsule. The release rate of progesterone was 3-20 times greater than that of the other steroids, while Norgestrel diffused at the lowest rate. The influence of thickness of capsule was greater for the steroids with the highest diffusion rate, progesterone and chlormadinone acetate. The release rates of all except chlormadinone acetate were higher in the 1st week. The release rates of the synthetic progestins, unlike that of progesterone, were relatively constant after the 1st week. The release rate of progesterone tended to be related to the amount remaining in the capsule when the amount became small. The measured amount of progesterone released each day from each intrauterine capsule was also proportional to its length. It appears that Norgestrel, Provera, and chlormadinone acetate are all released slowly enough and have enough biologic activity at low concentrations to have a contraceptive effect for well over 1 year when administered in a 30 mm intrauterine capsule.

Exercise in cold air and hydrogen peroxide release in exhaled breath condensate.

PubMed

Marek, E; Volke, J; Mückenhoff, K; Platen, P; Marek, W

2013-01-01

Athletes have changes in the lung epithelial cells caused by inhalation of cold and dry air. The exhaled breath condensate contains a number of mediators from the respiratory system and H(2)O(2) is described as a marker of airways inflammation. The aim of this study was to determine the influence of exercise combined with cold air on the H(2)O(2) release in the exhaled breath. Twelve males (23.1 ± 1.5 years) were randomly assigned at 2 different days (1 day rest) to perform a 50 min run (75-80% of their max. heart rate) under normal (N) laboratory (18.1 ± 1.1°C) or cold (C) field condition (-15.2 ± 3.1°C). Before and immediately after each run, the EBC was collected under laboratory conditions and was analyzed amperometrically. Prior to the two runs, H(2)O(2) concentrations were 145.0 ± 31.0 (N) and 160.0 ± 49.1 nmol/L (C) and theoretical release was 70.3 ± 37.1 (N) and 82.6 ± 27.1 pmol/min (C) (p > 0.05). After each run, H(2)O(2) concentration increased significantly to 388.0 ± 22.8 nmol/L (N) and 622.1 ± 44.2 nmol/L (C) (p < 0.05), along with an increase in the theoretical release: 249.2 ± 35.7 pmol/min (N) and 400.9 ± 35.7 pmol/min (C) (p < 0.05). We conclude that release of H(2)O(2) into the EBC takes place under both resting conditions and after exercise. The concentration and release of H(2)O(2) increased after exercise in cold air compared to resting and laboratory conditions, which points to an increase in inflammatory and oxidative stress.

Release of ICTP and CTX telopeptides from demineralized dentin matrices: Effect of time, mass and surface area.

PubMed

Turco, Gianluca; Cadenaro, Milena; Maravić, Tatjana; Frassetto, Andrea; Marsich, Eleonora; Mazzoni, Annalisa; Di Lenarda, Roberto; Tay, Franklin R; Pashley, David H; Breschi, Lorenzo

2018-03-01

The present study evaluated the influence of time, mass and surface area of demineralized dentin collagen matrices on telopeptides release. The hypotheses tested were that the rates of ICTP and CTX release by matrix bound endogenous proteases are 1) not time-dependent, 2) unrelated to specimen mass, 3) unrelated to specimen surface area. Non-carious human molars (N=24) were collected and randomly assigned to three groups. Dentin slabs with three different thicknesses: 0.37mm, 0.75mm, and 1.50mm were completely demineralized and stored in artificial saliva for one week. Collagen degradation was evaluated by sampling storage media for ICTP and CTX telopeptidases. Activity of MMPs in the aging medium was evaluated using fluorometric activity assay kit. A statistically significant (p<0.05) decrease in the release of both ICTP and CTX fragments over time was observed irrespective of the specimen thickness. When data were normalized by the specimen mass, no significant differences were observed. Releases of ICTP and CTX were significantly related to the aging time as a function of surface area for the first 12h. Total MMP activity, mainly related to MMP-2 and -9, decreased with time (p<0.05). Because the release of collagen fragments was influenced by specimen storage time and surface area, it is likely that cleaved collagen fragments closer to the specimen surface diffuse into the incubation medium; those further away from the exposed surface are still entrapped within the demineralized dentin matrix. Bound MMPs can only degrade the substrate within the limited zone of their molecular mobility. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Effects of absorption enhancers in chloroquine suppository formulations: I. In vitro release characteristics.

PubMed

Onyeji, C O; Adebayo, A S; Babalola, C P

1999-12-01

The need to develop chloroquine suppository formulations that yield optimal bioavailability of the drug has been emphasized. This study demonstrates the effects of incorporation of known absorption-enhancing agents (nonionic surfactants and sodium salicylate) on the in vitro release characteristics of chloroquine from polyethylene glycol (1000:4000, 75:25%, w/w) suppositories. The release rates were determined using a modification of the continuous flow bead-bed dissolution apparatus for suppositories. Results showed that the extent of drug release from suppositories containing any of three surfactants (Tween 20, Tween 80 and Brij 35) was 100%, whereas 88% release was obtained with control formulation (without enhancer) (P<0.05). However, Tween 20 was more effective than Brij 35 and Tween 80 in improving the drug release rate. There was a concentration-dependent effect with Tween 20, and 4% (w/w) of this surfactant was associated with the highest increase in the rate of drug release from the suppositories. Sodium salicylate at a concentration of 25% (w/w) also significantly enhanced the drug release rate, but a higher concentration of the adjuvant markedly reduced both the rate and extent of drug release. Combined incorporation of Tween 20 and sodium salicylate did not significantly modify (P0.05) the rate of drug release when compared to the effect of the more effective single agent. Due to their effects in improving the drug release profiles coupled with their intrinsic absorption-promoting properties, it is suggested that incorporation of 4% (w/w) Tween 20 and/or 25% (w/w) sodium salicylate in the composite polyethylene glycol chloroquine suppository formulations, may result in enhancement of rectal absorption of the drug. This necessitates an in vivo validation.

Mechanical energy storage device for hip disarticulation

NASA Technical Reports Server (NTRS)

Vallotton, W. C. (Inventor)

1977-01-01

An artificial leg including a trunk socket, a thigh section hingedly coupled to the trunk socket, a leg section hingedly coupled to the thigh section and a foot section hingedly coupled to the leg section is outlined. A mechanical energy storage device is operatively associated with the artificial leg for storage and release of energy during the normal walking stride of the user. Energy is stored in the mechanical energy storage device during a weight-bearing phase of the walking stride when the user's weight is on the artificial leg. Energy is released during a phase of the normal walking stride, when the user's weight is removed from the artificial leg. The stored energy is released from the energy storage device to pivot the thigh section forwardly about the hinged coupling to the trunk socket.

Drug Release Studies from Caesalpinia pulcherrima Seed Polysaccharide.

PubMed

Jeevanandham, Somasundaram; Dhachinamoorthi, Duraiswamy; Bannoth Chandra Sekhar, Kothapalli

2011-01-01

This study examines the controlled release behavior of both water-soluble (acetaminophen, caffeine, theophylline and salicylic acid) and water insoluble (indomethacin) drugs derived from Caesalpinia pulcherrima seed Gum isolated from Caesalpinia pulcherrima kernel powder. It further investigates the effect of incorporating diluents such as microcrystalline cellulose and lactose on caffeine release. In addition the effect the gum's (polysaccharide) partial cross-linking had on release of acetaminophen was examined. Applying the exponential equation, the soluble drugs mechanism of release was found to be anomalous. The insoluble drugs showed a near case II or zero order release mechanism. The rate of release in descending order was caffeine, acetaminophen, theophylline, salicylic acid and indomethacin. An increase in the release kinetics of the drug was observed on blending with diluents. However, the rate of release varied with the type and amount of blend within the matrix. The mechanism of release due to effect of diluents was found to be anomalous. The rate of drug release decreased upon partial cross-linking and the mechanism of release was found to be of super case II.

Segmentation of Slow Slip Events in South Central Alaska Possibly Controlled by a Subducted Oceanic Plateau

NASA Astrophysics Data System (ADS)

Li, Haotian; Wei, Meng; Li, Duo; Liu, Yajing; Kim, YoungHee; Zhou, Shiyong

2018-01-01

Recent GPS observations show that slow slip events in south central Alaska are segmented along strike. Here we review several mechanisms that might contribute to this segmentation and focus on two: along-strike variation of slab geometry and effective normal stress. We then test them by running numerical simulations in the framework of rate-and-state friction with a nonplanar fault geometry. Results show that the segmentation is most likely related to the along-strike variation of the effective normal stress on the fault plane caused by the Yakutat Plateau. The Yakutat Plateau could affect the effective normal stress by either lowering the pore pressure in Upper Cook Inlet due to less fluids release or increasing the normal stress due to the extra buoyancy caused by the subducted Yakutat Plateau. We prefer the latter explanation because it is consistent with the relative amplitudes of the effective normal stress in Upper and Lower Cook Inlet and there is very little along-strike variation in Vp/Vs ratio in the fault zone from receiver function analysis. However, we cannot exclude the possibility that the difference in effective normal stress results from along-strike variation of pore pressure due to the uncertainties in the Vp/Vs estimates. Our work implies that a structural anomaly can have a long-lived effect on the subduction zone slip behavior and might be a driving factor on along-strike segmentation of slow slip events.

Targeting MMP-13 in bronchial epithelial repair.

PubMed

Howell, Christopher; Smith, James R; Shute, Janis K

2018-06-20

Viral infection of the bronchial epithelium disrupts the barrier properties of the epithelium in healthy individuals and those with lung disease. Repair of the bronchial epithelium is dependent of the formation of a provisional fibrin matrix and migration of epithelial cells to cover denuded areas, followed by proliferation and differentiation. The objective was to test the hypothesis that poly I:C, a model of viral infection, limits epithelial repair through the stimulated release of matrix metalloproteinase-13 (MMP-13). Confluent layers of cultured normal human primary bronchial epithelial cells (NHBE) and SV-40 virus transformed 16HBE14o- bronchial epithelial cells were mechanically wounded, and video microscopy used to measure the rate of wound closure over 2 hours, in the absence and presence of poly I:C (1-20 μg/ml). MMP-13, tissue factor and endothelin release were measured by ELISA. The effect of inhibitors of MMP-13 activity and expression and a non-specific endothelin receptor antagonist, bosentan, on the rate of epithelial repair was investigated RESULTS: Poly I:C limited the rate of epithelial repair, and NHBE were significantly more sensitive to poly I:C effects than 16HBE14o- cells. NHBE, but not 16HBE14o-, released MMP-13 in response to poly I:C. Inhibitors of MMP-13 activity (WAY 170523) and expression (dimethyl fumarate) significantly enhanced the rate of repair. Bosentan enhanced the rate of bronchial epithelial repair by a mechanism that was independent of MMP-13. Bronchial epithelial repair is limited by endothelin and by MMP-13, a protease that degrades coagulation factors, such as fibrinogen, and matrix proteins essential for epithelial repair. Further studies with primary cells from patients are needed to confirm whether repurposing bosentan and inhibitors of MMP-13 expression or activity, for inhalation may be a useful therapeutic strategy in diseases where repeated cycles of epithelial injury and repair occur, such as asthma and COPD. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

The effect of acute exercise on pulsatile release of luteinizing hormone in women runners.

PubMed

Cumming, D C; Vickovic, M M; Wall, S R; Fluker, M R; Belcastro, A N

1985-11-01

Endurance exercise has been associated with reproductive dysfunction. We have previously suggested that pulsatile release of luteinizing hormone is impaired at rest in normal menstruating runners compared with sedentary women. To determine whether acute exercise had any effect on pulsatile release of luteinizing hormone we investigated serum luteinizing hormone levels in six normal menstruating runners at rest and after 60 minutes of running exercise. Exercise induced an increment in circulating luteinizing hormone levels greater than the change in hematocrit. The luteinizing hormone pulse frequency, calculated as the number of luteinizing hormone pulses per 6 hours, was reduced after exercise compared with values obtained at rest. There was no significant difference in pulse amplitude or area under the 6-hour curve between resting and postexercise situations. These data suggest that acute exercise has an inhibitory effect on luteinizing hormone pulsatile release at the hypothalamic level in eumenorrheic runners that is in addition to the previously described effect of training.

Endogenous pyrogen production by Hodgkin's disease and human histiocytic lymphoma cell lines in vitro.

PubMed

Bodel, P; Ralph, P; Wenc, K; Long, J C

1980-02-01

Fever not explained by infection may occur in patients with malignant lymphoma presumably caused by a release of endogenous pyrogen. Although pyrogen has been found in some tumors with a mixed cell population, production of endogenous pyrogen by the neoplastic cells has not been demonstrated. This report documents the apparently spontaneous synthesis and release of such pyrogen by two human tumor cell lines derived from patients with Hodgkin's disease and histiocytic lymphoma. The endogenous pyrogen from the two cell lines was similar and closely resembled that produced by normal human monocytes in antigenic properties as well as heat and pronase sensitivity. The Hodgkin's disease and histiocytic lymphoma cell lines do not require specific stimulation for the production of endogenous pyrogen suggesting that the mechanism of pyrogen release by neoplastic macrophage-related cells differs from that of normal phagocytic cells. The tumor-associated fever in some patients with malignant lymphoma may be caused by a release of endogenous pyrogen by proliferating neoplastic cells.

Endogenous pyrogen production by Hodgkin's disease and human histiocytic lymphoma cell lines in vitro.

PubMed Central

Bodel, P; Ralph, P; Wenc, K; Long, J C

1980-01-01

Fever not explained by infection may occur in patients with malignant lymphoma presumably caused by a release of endogenous pyrogen. Although pyrogen has been found in some tumors with a mixed cell population, production of endogenous pyrogen by the neoplastic cells has not been demonstrated. This report documents the apparently spontaneous synthesis and release of such pyrogen by two human tumor cell lines derived from patients with Hodgkin's disease and histiocytic lymphoma. The endogenous pyrogen from the two cell lines was similar and closely resembled that produced by normal human monocytes in antigenic properties as well as heat and pronase sensitivity. The Hodgkin's disease and histiocytic lymphoma cell lines do not require specific stimulation for the production of endogenous pyrogen suggesting that the mechanism of pyrogen release by neoplastic macrophage-related cells differs from that of normal phagocytic cells. The tumor-associated fever in some patients with malignant lymphoma may be caused by a release of endogenous pyrogen by proliferating neoplastic cells. PMID:6985918

Montmorillonite dissolution kinetics: Experimental and reactive transport modeling interpretation

NASA Astrophysics Data System (ADS)

Cappelli, Chiara; Yokoyama, Shingo; Cama, Jordi; Huertas, F. Javier

2018-04-01

The dissolution kinetics of K-montmorillonite was studied at 25 °C, acidic pH (2-4) and 0.01 M ionic strength by means of well-mixed flow-through experiments. The variations of Si, Al and Mg over time resulted in high releases of Si and Mg and Al deficit, which yielded long periods of incongruent dissolution before reaching stoichiometric steady state. This behavior was caused by simultaneous dissolution of nanoparticles and cation exchange between the interlayer K and released Ca, Mg and Al and H. Since Si was only involved in the dissolution reaction, it was used to calculate steady-state dissolution rates, RSi, over a wide solution saturation state (ΔGr ranged from -5 to -40 kcal mol-1). The effects of pH and the degree of undersaturation (ΔGr) on the K-montmorillonite dissolution rate were determined using RSi. Employing dissolution rates farthest from equilibrium, the catalytic pH effect on the K-montmorillonite dissolution rate was expressed as Rdiss = k·aH0.56±0.05 whereas using all dissolution rates, the ΔGr effect was expressed as a non-linear f(ΔGr) function Rdiss = k · [1 - exp(-3.8 × 10-4 · (|ΔGr|/RT)2.13)] The functionality of this expression is similar to the equations reported for dissolution of Na-montmorillonite at pH 3 and 50 °C (Metz, 2001) and Na-K-Ca-montmorillonite at pH 9 and 80 °C (Cama et al., 2000; Marty et al., 2011), which lends support to the use of a single f(ΔGr) term to calculate the rate over the pH range 0-14. Thus, we propose a rate law that also accounts for the effect of pOH and temperature by using the pOH-rate dependence and the apparent activation energy proposed by Rozalén et al. (2008) and Amram and Ganor (2005), respectively, and normalizing the dissolution rate constant with the edge surface area of the K-montmorillonite. 1D reactive transport simulations of the experimental data were performed using the Crunchflow code (Steefel et al., 2015) to quantitatively interpret the evolution of the released cations and to elucidate the stoichiometry of the reaction. After the implementation of (i) the obtained f(ΔGr) term in the K-montmorillonte dissolution rate law, (ii) a fraction of highly reactive particles and surfaces and (iii) the cation exchange reactions between the interlayer K+ and the released Al3+, Mg2+, Ca2+ and H+, the simulations agreed with the experimental concentrations at the outlet. This match indicates that fast dissolution of fine particles and highly reactive sites and exchange between the interlayer K and dissolved structural cations (Al and Mg) and protons are responsible for the temporary incongruency of the K-montmorillonite dissolution reaction. As long as dissolution of the bulk sample predominates, the reaction is stoichiometric.

Subjective effects of slow-release bupropion versus caffeine as determined in a quasi-naturalistic setting.

PubMed

Zernig, Gerald; De Wit, Harriet; Telser, Stefan; Nienhusmeier, Matthias; Wakonigg, Gudrun; Sturm, Katja; Berger, Iris; Kemmler, Georg; Saria, Alois

2004-04-01

Bupropion (BUP), which in its slow-release formulation (Zyban) is used as a smoking-cessation drug, increases dopamine overflow in the nucleus accumbens and serves as a reinforcer in animal experiments, both suggesting that BUP may possess some abuse liability. The present study examined if BUP produced subjective effects indicative of abuse liability in a quasi-naturalistic setting, with caffeine (CAF) serving as a positive control. In a randomized double-blind crossover design, male smokers (n = 50) ingested two doses (interdosing interval, 6 h) of placebo (PLC), 178 mg CAF, or 150 mg slow-release BUP in their normal mid-week work environment. They completed questionnaires administered by telephone at regular intervals. CAF significantly increased ratings of 'pleasant effects' (p = 0.008) and 'high' (p = 0.03), whereas BUP produced a 'high' of only very moderate size (p = 0.02). In 3 subjects each, BUP or CAF produced ratings of 'pleasant effects' that were >9-fold higher than those for PLC. Finally, BUP increased the number of cigarettes smoked by 29% (i.e., from 24 to 31 per day; p = 0.004) only in those subjects who were unable to report any effect of either BUP or CAF. CAF had no effect on cigarette consumption. These findings suggest that BUP, like CAF, might be of some abuse liability in a small subgroup of smokers (i.e., 6% each of the present sample), and it may transiently increase, rather than decrease, smoking during early phases of treatment in continuing smokers. Copyright 2004 S. Karger AG, Basel

Impact winter and the Cretaceous/Tertiary extinctions: Results of a Chicxulub asteroid impact model

NASA Technical Reports Server (NTRS)

Pope, Kevin O.; Baines, Kevin H.; Ocampo, Adriana C.; Ivanov, Boris A.

1994-01-01

The Chicxulub impact crater in Mexico is the site of the impact purported to have caused mass extinctions at the Cretaceous/Tertiary (K/T) boundary. 2-D hydrocode modeling of the impact, coupled with studies of the impact site geology, indiate that between 0.4 and 7.0 x 10(exp 17) g of sulfur were vaporized by the impact into anhydrite target rocks. A small portion of the sulfur was released as SO3 or SO4, which converted rapidly into H2SO4 aerosol and fell as acid rain. A radiative transfer model, coupled with a model of coagulation indicates that the aerosol prolonged the initial blackout period caused by impact dust only if the aerosol contained impurities. A larger portion of sulfur was released as SO2, which converted to aerosol slowly, due to the rate-limiting oxidation of SO2. Our radiative transfer calculations, combined with rates of acid production, coagulation, and diffusion indicate that solar transmission was reduced to 10-20% of normal for a period of 8-13 yr. This reduction produced a climate forcing (cooling) of -300 W/sq.m, which far exceeded the +8 W/sq.m greenhouse warming, caused by the CO2 released through the vaporization of carbonates, and therefore produced a decade of freezing and near-freezing temperatures. Several decades of moderate warming followed the decade of severe cooling due to the long residence time of CO2. The prolonged impact winter may have been a major cause of the K/T extinctions.

Reintroduction medicine: whooping cranes in Wisconsin.

PubMed

Keller, Dominique L; Hartup, Barry K

2013-01-01

This paper presents veterinary management strategies and diagnostic findings in the reintroduction of the endangered whooping crane (Grus americana). Between 2005 and 2010, 63 (27 male, 36 female) hatchling whooping cranes were assigned to a reintroduction project involving autumn release of costume-reared chicks in Wisconsin. Veterinary care included preventive measures and comprehensive pre-release evaluations to improve fitness and reduce translocation of potential disease agents to native habitats. A total of 44 clinically normal birds were released (70% of assigned individuals). Cases of morbidity were classified according to primary body system affected. Musculoskeletal disorders were described in 57 birds (90%); five birds were removed from the project prior to release (8%), all for abnormalities that prevented normal function. Fourteen birds died or were euthanized prior to release (22%); pre-release mortality was attributed to developmental abnormality, predation, trauma or infectious disease. Chronic respiratory aspergillosis, diagnosed in seven birds (11%), was the most common infectious disease of concern. Predation and trauma were primary causes of post-release mortality; no evidence of infectious disease of captive origin was detected in the study population by the end of 2010. The assessment of data accumulated by this project helped to outline successful health management strategies, as well as identify and mitigate ongoing risks to captive whooping cranes that impede reintroduction efforts and achieving management goals for species recovery. © 2013 Wiley Periodicals, Inc.

Mice Lacking Pannexin 1 Release ATP and Respond Normally to All Taste Qualities.

PubMed

Vandenbeuch, Aurelie; Anderson, Catherine B; Kinnamon, Sue C

2015-09-01

Adenosine triphosphate (ATP) is required for the transmission of all taste qualities from taste cells to afferent nerve fibers. ATP is released from Type II taste cells by a nonvesicular mechanism and activates purinergic receptors containing P2X2 and P2X3 on nerve fibers. Several ATP release channels are expressed in taste cells including CALHM1, Pannexin 1, Connexin 30, and Connexin 43, but whether all are involved in ATP release is not clear. We have used a global Pannexin 1 knock out (Panx1 KO) mouse in a series of in vitro and in vivo experiments. Our results confirm that Panx1 channels are absent in taste buds of the knockout mice and that other known ATP release channels are not upregulated. Using a luciferin/luciferase assay, we show that circumvallate taste buds from Panx1 KO mice normally release ATP upon taste stimulation compared with wild type (WT) mice. Gustatory nerve recordings in response to various tastants applied to the tongue and brief-access behavioral testing with SC45647 also show no difference between Panx1 KO and WT. These results confirm that Panx1 is not required for the taste evoked release of ATP or for neural and behavioral responses to taste stimuli. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Corticotropin-releasing factor accelerates metamorphosis in Bufo arenarum: effect on pituitary ACTH and TSH cells.

PubMed

Miranda, L A; Affanni, J M; Paz, D A

2000-04-01

The actions of several neuropeptides as hypothalamic mediators in the regulation of Bufo arenarum metamorphosis were investigated. Prometamorphic larvae were injected with 1.5 microg thyrotropin-releasing hormone (TRH), 2 microg ovine corticotropin-releasing factor (oCRF), 2 microg mammalian gonadotropin-releasing hormone (mGnRH), 2 microg human growth hormone-releasing hormone (hGHRH), or Holtfreter solution (control group). Larvae received two injections with the same dose: one at the beginning of the experiment and the other 7 days later. Several morphologic parameters (total length, tail length, wet weight, hind limb length, and metamorphic stages) were measured as indicators of growth and metamorphic development. These measurements were taken in 20 larvae per treatment or control group at the beginning of the experiment, at day 7 and at day 14 when the experiment ended. We observed that only the administration of exogenous CRF stimulated resorption of the tail and accelerated the rate of metamorphosis. In the pituitary of CRF-treated larvae we observed that thyrotropin (TSH) and adrenocorticotropic hormone (ACTH) producing cells showed a weaker immunoreactivity, a decrease in cell number and a reduction of volume density when compared with normal larvae. In conclusion, the results obtained indicate a possible role for CRF in Bufo arenarum metamorphosis. CRF may regulate interrenal and thyroid activity by acting directly upon TSH and ACTH cells. On the other hand, TRH, GnRH and GHRH were inactive in stimulating growth or metamorphosis of Bufo arenarum. J. Exp. Zool. 286:473-480, 2000. Copyright 2000 Wiley-Liss, Inc.

Ageing of a phosphate ceramic used to immobilize chloride contaminated actinide waste

NASA Astrophysics Data System (ADS)

Metcalfe, B. L.; Donald, I. W.; Fong, S. K.; Gerrard, L. A.; Strachan, D. M.; Scheele, R. D.

2009-03-01

A process for the immobilization of intermediate level waste containing a significant quantity of chloride using Ca3(PO4)2 as the host material has been developed. Waste ions are incorporated into two phosphate-based phases, chlorapatite [Ca5(PO4)3Cl] and spodiosite [Ca2(PO4)Cl]. Non-active trials performed using Sm as the actinide surrogate demonstrated the durability of these phases in aqueous solution. Trials of the process, in which actinide-doped materials were used, were performed at PNNL which confirmed the wasteform resistant to aqueous leaching. Initial leach trials conducted on 239Pu/241Am loaded ceramic at 313 K/28 days gave normalized mass losses of 1.2 × 10-5 g m-2 and 2.7 × 10-3 g m-2 for Pu and Cl, respectively. In order to assess the response of the phases to radiation-induced damage, accelerated ageing trials were performed on samples in which the 239Pu was replaced with 238Pu. No changes to the crystalline structure of the waste were detected in the XRD spectra after the samples had experienced an α radiation fluence of 4 × 1018 g-1. Leach trials showed that there was an increase in the P and Ca release rates but no change in the Pu release rate.

Sustained release of corticosterone in rats affects reactivity, but does not affect habituation to immobilization and acoustic stimuli.

PubMed

Tanke, Marit A C; Fokkema, Dirk S; Doornbos, Bennard; Postema, Folkert; Korf, Jakob

2008-07-18

Depression is often preceded by stressful life events and accompanied with elevated cortisol levels and glucocorticoid resistance. It has been suggested that a major depressive disorder may result from impaired coping with and adaptation to stress. The question is whether or not hypothalamus-pituitary-adrenal (HPA)-axis dysfunction influences the process of adaptation. We examined the effect of a dysregulated HPA-axis on the adaptation to acoustic stimuli in rats with or without preceding restraint stress. HPA-axis function was altered via slow release of corticosterone (CORT, 90 mg) from subcutaneously implanted pellets for 7 or 14 days. The rate of body temperature increases during restraint (10 min) and the response to acoustic stimuli (of 80+120 dB) were used to quantify daily stress reactivity. Rats habituated to either stress regardless of CORT treatment. CORT treatment combined with restraint decreased the initial reactivity and the variability in response, but the rate of habituation was not influenced. These results show that suppressing normal HPA-axis function by chronic exposure to CORT does affect the course of habituation, but not habituation per se. This implies that altered HPA-axis function in depressed patients may not be causally related to stress coping, but instead may influence the course of the disorder.

The interaction between tropomyosin-related kinase B receptors and presynaptic muscarinic receptors modulates transmitter release in adult rodent motor nerve terminals.

PubMed

Garcia, Neus; Tomàs, Marta; Santafé, Manel M; Besalduch, Nuria; Lanuza, Maria A; Tomàs, Josep

2010-12-08

The neurotrophin brain-derived neurotrophic factor (BDNF), neurotrophin-4 (NT-4) and the receptors tropomyosin-related kinase B (trkB) and p75(NTR) are present in the nerve terminals on the neuromuscular junctions (NMJs) of the levator auris longus muscle of the adult mouse. Exogenously added BDNF or NT-4 increased evoked ACh release after 3 h. This presynaptic effect (the size of the spontaneous potentials is not affected) is specific because it is not produced by neurotrophin-3 (NT-3) and is prevented by preincubation with trkB-IgG chimera or by pharmacological block of trkB [K-252a (C₂₇H₂₁N₃O₅)] or p75(NTR) [Pep5 (C₈₆H₁₁₁N₂₅O₁₉S₂] signaling. The effect of BDNF depends on the M₁ and M₂ muscarinic acetylcholine autoreceptors (mAChRs) because it is prevented by atropine, pirenzepine and methoctramine. We found that K-252a incubation reduces ACh release (~50%) in a short time (1 h), but the p75(NTR) signaling inhibitor Pep5 does not have this effect. The specificity of the K-252a blocking effect on trkB was confirmed with the anti-trkB antibody 47/trkB, which reduces evoked ACh release, like K-252a, whereas the nonpermeant tyrosine kinase blocker K-252b does not. Neither does incubation with the fusion protein trkB-IgG (to chelate endogenous BDNF/NT-4), anti-BDNF or anti-NT-4 change ACh release. Thus, the trkB receptor normally seems to be coupled to ACh release when there is no short-term local effect of neurotrophins at the NMJ. The normal function of the mAChR mechanism is a permissive prerequisite for the trkB pathway to couple to ACh release. Reciprocally, the normal function of trkB modulates M₁- and M₂-subtype muscarinic pathways.

Residual thermal and moisture influences on the strain energy release rate analysis of local delaminations from matrix cracks

NASA Technical Reports Server (NTRS)

Obrien, T. K.

1991-01-01

An analysis utilizing laminated plate theory is developed to calculate the strain energy release rate associated with local delaminations originating at off-axis, single ply, matrix cracks in laminates subjected to uniaxial loads. The analysis includes the contribution of residual thermal and moisture stresses to the strain energy released. Examples are calculated for the strain energy release rate associated with local delaminations originating at 90 degrees and angle-ply (non-90 degrees) matrix ply cracks in glass epoxy and graphite epoxy laminates. The solution developed may be used to assess the relative contribution of mechanical, residual thermal, and moisture stresses on the strain energy release rate for local delamination for a variety of layups and materials.

38 CFR 4.30 - Convalescent ratings.

Code of Federal Regulations, 2010 CFR

2010-07-01

... RATING DISABILITIES General Policy in Rating § 4.30 Convalescent ratings. A total disability rating (100... by report at hospital discharge (regular discharge or release to non-bed care) or outpatient release... total ratings will not be subject to § 3.105(e) of this chapter. Such total rating will be followed by...

Early Recovery of an Eastern Sierra Nevada Riparian System After 40 Years of Stream Diversion

Treesearch

Julie C. Stromberg; Duncan T. Patten

1989-01-01

Rush Creek, which feeds Mono Lake, has been diverted below Grant Lake, totally or in part, for over 40 years. In the early 1980's, because of above normal snow packs, runoff was released into the creek. Minimum flow releases have also been established. The riparian vegetation has responded to these releases. In a few areas, riparian trees and shrubs (e.g., black...

Drug release through liposome pores.

PubMed

Dan, Nily

2015-02-01

Electrical, ultrasound and other types of external fields are known to induce the formation of pores in cellular and model membranes. This paper examines drug release through field induced liposome pores using Monte Carlo simulations. We find that drug release rates vary as a function of pore size and spacing, as well as the overall fraction of surface area covered by pores: The rate of release from liposomes is found to increase rapidly with pore surface coverage, approaching that of the fully ruptured liposome at fractional pore areas. For a given pore surface coverage, the pore size affects the release rate in the limit of low coverage, but not when the pores cover a relatively high fraction of the liposome surface area. On the other hand, for a given pore size and surface coverage, the distribution of pores significantly affects the release in the limit of high surface coverage: The rate of release from a liposome covered with a regularly spaced array of pores is, in this limit, higher than the release rate from (most) systems where the pores are distributed randomly on the liposome surface. In contrast, there is little effect of the pore distribution on release when the pore surface coverage is low. The simulation results are in good agreement with the predictions of detailed diffusion models. Copyright © 2014 Elsevier B.V. All rights reserved.

Quantification of Kinetic Rate Law Parameters of Uranium Release from Sodium Autunite as a Function of Aqueous Bicarbonate Concentrations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gudavalli, Ravi; Katsenovich, Yelena; Wellman, Dawn M.

2013-09-05

ABSTRACT: Hydrogen carbonate is one of the most significant components within the uranium geochemical cycle. In aqueous solutions, hydrogen carbonate forms strong complexes with uranium. As such, aqueous bicarbonate may significantly increase the rate of uranium release from uranium minerals. Quantifying the relationship of aqueous hydrogen carbonate solutions to the rate of uranium release during dissolution is critical to understanding the long-term fate of uranium within the environment. Single-pass flow-through (SPTF) experiments were conducted to estimate the rate of uranium release from Na meta-autunite as a function of bicarbonate solutions (0.0005-0.003 M) under the pH range of 6-11 and temperaturesmore » of 5-60oC. Consistent with the results of previous investigation, the rate of uranium release from sodium autunite exhibited minimal dependency on temperature; but were strongly dependent on pH and increasing concentrations of bicarbonate solutions. Most notably at pH 7, the rate of uranium release exhibited 370 fold increases relative to the rate of uranium release in the absence of bicarbonate. However, the effect of increasing concentrations of bicarbonate solutions on the release of uranium was significantly less under higher pH conditions. It is postulated that at high pH values, surface sites are saturated with carbonate, thus the addition of more bicarbonate would have less effect on uranium release. Results indicate the activation energies were unaffected by temperature and bicarbonate concentration variations, but were strongly dependent on pH conditions. As pH increased from 6 to 11, activation energy values were observed to decrease from 29.94 kJ mol-1 to 13.07 kJ mol-1. The calculated activation energies suggest a surface controlled dissolution mechanism.« less

Evaluation of growth hormone release and human growth hormone treatment in children with cranial irradiation-associated short stature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Romshe, C.A.; Zipf, W.B.; Miser, A.

1984-02-01

We studied nine children who had received cranial irradiation for various malignancies and subsequently experienced decreased growth velocity. Their response to standard growth hormone stimulation and release tests were compared with that in seven children with classic GH deficiency and in 24 short normal control subjects. With arginine and L-dopa stimulation, six of nine patients who received radiation had a normal GH response (greater than 7 ng/ml), whereas by design none of the GH deficient and all of the normal children had a positive response. Only two of nine patients had a normal response to insulin hypoglycemia, with no significantmore » differences in the mean maximal response of the radiation and the GH-deficient groups. Pulsatile secretion was not significantly different in the radiation and GH-deficient groups, but was different in the radiation and normal groups. All subjects in the GH-deficient and radiation groups were given human growth hormone for 1 year. Growth velocity increased in all, with no significant difference in the response of the two groups when comparing the z scores for growth velocity of each subject's bone age. We recommend a 6-month trial of hGH in children who have had cranial radiation and are in prolonged remission with a decreased growth velocity, as there is no completely reliable combination of GH stimulation or release tests to determine their response.« less

Controlled release of insect sex pheromones from paraffin wax and emulsions.

PubMed

Atterholt, C A; Delwiche, M J; Rice, R E; Krochta, J M

1999-02-22

Paraffin wax and aqueous paraffin emulsions can be used as controlled release carriers for insect sex pheromones for mating disruption of orchard pests. Paraffin can be applied at ambient temperature as an aqueous emulsion, adheres to tree bark or foliage, releases pheromone for an extended period of time, and will slowly erode from bark and biodegrade in soil. Pheromone emulsions can be applied with simple spray equipment. Pheromone release-rates from paraffin were measured in laboratory flow-cell experiments. Pheromone was trapped from an air stream with an adsorbent, eluted periodically, and quantified by gas chromatography. Pheromone release from paraffin was partition-controlled, providing a constant (zero-order) release rate. A typical paraffin emulsion consisted of 30% paraffin, 4% pheromone, 4% soy oil, 1% vitamin E, 2% emulsifier, and the balance water. Soy oil and vitamin E acted as volatility suppressants. A constant release of oriental fruit moth pheromone from paraffin emulsions was observed in the laboratory for more than 100 days at 27 degreesC, with release-rates ranging from 0.4 to 2 mg/day, depending on the concentration and surface area of the dried emulsion. The use of paraffin emulsions is a viable method for direct application of insect pheromones for mating disruption. Sprayable formulations can be designed to release insect pheromones to the environment at a rate necessary for insect control by mating disruption. At temperatures below 38 degreesC, zero-order release was observed. At 38 degreesC and higher, pheromone oxidation occurred. A partition-controlled release mechanism was supported by a zero-order pheromone release-rate, low air/wax partition coefficients, and pheromone solubility in paraffin.

Liquid-Phase Heat-Release Rates of the Systems Hydrazine-Nitric Acid and Unsymmetrical Dimethylhydrazine-Nitric Acid

NASA Technical Reports Server (NTRS)

Somogyi, Dezso; Feiler, Charles E.

1960-01-01

The initial rates of heat release produced by the reactions of hydrazine and unsymmetrical dimethylhydrazine with nitric acid were determined in a bomb calorimeter under conditions of forced mixing. Fuel-oxidant weight ratio and injection velocity were varied. The rate of heat release apparently depended on the interfacial area between the propellants. Above a narrow range of injection velocities representing a critical amount of interfacial area, the rates reached a maximum and were almost constant with injection velocity. The maximum rate for hydrazine was about 70 percent greater than that for unsymmetrical dimethylhydrazine. The total heat released did not vary with mixture ratio over the range studied.

Transit losses and traveltimes for water-supply releases Marion Lake during drought conditions, Cottonwood River, east-central Kansas

USGS Publications Warehouse

Jordan, P.R.; Hart, R.J.

1985-01-01

A streamflow routing model was used to calculate the transit losses and traveltimes. Channel and aquifer characteristics, and the model control parameters, were estimated from available data and then verified to the extent possible by comparing model simulated streamflow to observed streamflow at streamflow gaging stations. Transit losses and traveltimes for varying reservoir release rates and durations then were simulated for two different antecedent streamflow (drought) conditions. For the severe-drought antecedent-streamflow condition, it was assumed that only the downstream water use requirement would be released from the reservoir. For a less severe drought (LSD) antecedent streamflow condition, it was assumed than any releases from Marion Lake for water supply use downstream, would be in addition to a nominal dry weather release of 5 cu ft/sec. Water supply release rates of 10 and 25 cu ft/sec for the severe drought condition and 5, 10, and 25 cu ft/sec for the less severe drought condition were simulated for periods of 28 and 183 days commencing on July 1. Transit losses for the severe drought condition for all reservoir release rates and durations ranged from 12% to 78% of the maximum downstream flow rate and from 27% to 91% of the total volume of reservoir storage released. For the LSD condition, transit losses ranged from 7% to 29% of the maximum downstream flow rate and from 10% to 48% of the total volume of release. The 183-day releases had larger total transit losses, but losses on a percentage basis were less than the losses for the 28-day release period for both antecedent streamflow conditions. Traveltimes to full response (80% of the maximum downstream flow rate), however, showed considerable variation. For the release of 5 cu ft/sec during LSD conditions, base flow exceeded 80% of the maximum flow rate near the confluence; the traveltime to full response was undefined for those simulations. For the releases of 10 and 25 cu ft/sec during the same drought condition, traveltimes to full response ranged from 4.4 to 6.5 days. For releases of 10 and 25 cu ft/sec during severe drought conditions, traveltimes to full response near the confluence with the Neosho River ranged from 8.3 to 93 days. (Lantz-PTT)

Effects of pH, Temperature, Dissolved Oxygen, and Flow Rate on Phosphorus Release Processes at the Sediment and Water Interface in Storm Sewer

PubMed Central

Li, Haiyan; Li, Mingyi; Zhang, Xiaoran

2013-01-01

The effects of pH, temperature, dissolved oxygen (DO), and flow rate on the phosphorus (P) release processes at the sediment and water interface in rainwater pipes were investigated. The sampling was conducted in a residential storm sewer of North Li Shi Road in Xi Cheng District of Beijing on August 3, 2011. The release rate of P increased with the increase of pH from 8 to 10. High temperature is favorable for the release of P. The concentration of total phosphorus (TP) in the overlying water increased as the concentration of DO decreased. With the increase of flow rate from 0.7 m s−1 to 1.1 m s−1, the concentration of TP in the overlying water increased and then tends to be stable. Among all the factors examined in the present study, the flow rate is the primary influence factor on P release. The cumulative amount of P release increased with the process of pipeline runoff in the rainfall events with high intensities and shorter durations. Feasible measures such as best management practices and low-impact development can be conducted to control the P release on urban sediments by slowing down the flow rate. PMID:24349823

Evolution and modulation of intracellular calcium release during long-lasting, depleting depolarization in mouse muscle

PubMed Central

Royer, Leandro; Pouvreau, Sandrine; Ríos, Eduardo

2008-01-01

Intracellular calcium signals regulate multiple cellular functions. They depend on release of Ca2+ from cellular stores into the cytosol, a process that in many types of cells appears to be tightly controlled by changes in [Ca2+] within the store. In contrast with cardiac muscle, where depletion of Ca2+ in the sarcoplasmic reticulum is a crucial determinant of termination of Ca2+ release, in skeletal muscle there is no agreement regarding the sign, or even the existence of an effect of SR Ca2+ level on Ca2+ release. To address this issue we measured Ca2+ transients in mouse flexor digitorum brevis (FDB) skeletal muscle fibres under voltage clamp, using confocal microscopy and the Ca2+ monitor rhod-2. The evolution of Ca2+ release flux was quantified during long-lasting depolarizations that reduced severely the Ca2+ content of the SR. As in all previous determinations in mammals and non-mammals, release flux consisted of an early peak, relaxing to a lower level from which it continued to decay more slowly. Decay of flux in this second stage, which has been attributed largely to depletion of SR Ca2+, was studied in detail. A simple depletion mechanism without change in release permeability predicts an exponential decay with time. In contrast, flux decreased non-exponentially, to a finite, measurable level that could be maintained for the longest pulses applied (1.8 s). An algorithm on the flux record allowed us to define a quantitative index, the normalized flux rate of change (NFRC), which was shown to be proportional to the ratio of release permeability P and inversely proportional to Ca2+ buffering power B of the SR, thus quantifying the ‘evacuability’ or ability of the SR to empty its content. When P and B were constant, flux then decayed exponentially, and NFRC was equal to the exponential rate constant. Instead, in most cases NFRC increased during the pulse, from a minimum reached immediately after the early peak in flux, to a time between 200 and 250 ms, when the index was no longer defined. NFRC increased by 111% on average (in 27 images from 18 cells), reaching 300% in some cases. The increase may reflect an increase in P, a decrease in B, or both. On experimental and theoretical grounds, both changes are to be expected upon SR depletion. A variable evacuability helps maintain a constant Ca2+ output under conditions of diminishing store Ca2+ load. PMID:18687715

Rate of Heat Release in Diesel Engines

DOT National Transportation Integrated Search

1977-10-01

In this report, the concept of heat release in diesel engines is compared with reaction rates in petrol engines as a means of describing combustion. The intimate relationships between heat release, cylinder pressure development and cylinder pressure ...

A Demonstration of Sympathetic Cotransmission

ERIC Educational Resources Information Center

Johnson, Christopher D.

2010-01-01

Currently, most undergraduate textbooks that cover the autonomic nervous system retain the concept that autonomic nerves release either acetylcholine or norepinephrine. However, in recent years, a large volume of research has superseded this concept with one in which autonomic nerves normally release at least one cotransmitter along with a…

Optimization and development of a core-in-cup tablet for modulated release of theophylline in simulated gastrointestinal fluids.

PubMed

Danckwerts, M P

2000-07-01

A triple-layer core-in-cup tablet that can release theophylline in simulated gastrointestinal (GI) fluids at three distinct rates has been developed. The first layer is an immediate-release layer; the second layer is a sustained-release layer; and the last layer is a boost layer, which was designed to coincide with a higher nocturnal dose of theophylline. The study consisted of two stages. The first stage optimized the sustained-release layer of the tablet to release theophylline over a period of 12 hr. Results from this stage indicated that 30% w/w acacia gum was the best polymer and concentration to use when compressed to a hardness of 50 N/m2. The second stage of the study involved the investigation of the final triple-layer core-in-cup tablet to release theophylline at three different rates in simulated GI fluids. The triple-layer modulated core-in-cup tablet successfully released drug in simulated fluids at an initial rate of 40 mg/min, followed by a rate of 0.4085 mg/min, in simulated gastric fluid TS, 0.1860 mg/min in simulated intestinal fluid TS, and finally by a boosted rate of 0.6952 mg/min.

Nuclear reactor control apparatus

DOEpatents

Sridhar, Bettadapur N.

1983-11-01

Nuclear reactor core safety rod release apparatus comprises a control rod having a detent notch in the form of an annular peripheral recess at its upper end, a control rod support tube for raising and lowering the control rod under normal conditions, latches pivotally mounted on the control support tube with free ends thereof normally disposed in the recess in the control rod, and cam means for pivoting the latches out of the recess in the control rod when a scram condition occurs. One embodiment of the invention comprises an additional magnetically-operated latch for releasing the control rod under two different conditions, one involving seismic shock.

Effect of detention basin release rates on flood flows - Application of a model to the Blackberry Creek Watershed in Kane County, Illinois

USGS Publications Warehouse

Soong, David T.; Murphy, Elizabeth A.; Straub, Timothy D.

2009-01-01

The effects of stormwater detention basins with specified release rates are examined on the watershed scale with a Hydrological Simulation Program - FORTRAN (HSPF) continuous-simulation model. Modeling procedures for specifying release rates from detention basins with orifice and weir discharge configurations are discussed in this report. To facilitate future detention modeling as a tool for watershed management, a chart relating watershed impervious area to detention volume is presented. The report also presents a case study of the Blackberry Creek watershed in Kane County, Ill., a rapidly urbanizing area seeking to avoid future flood damages from increased urbanization, to illustrate the effects of various detention basin release rates on flood peaks and volumes and flood frequencies. The case study compares flows simulated with a 1996 land-use HSPF model to those simulated with four different 2020 projected land-use HSPF model scenarios - no detention, and detention basins with release rates of 0.08, 0.10, and 0.12 cubic feet per second per acre (ft3/s-acre), respectively. Results of the simulations for 15 locations, which included the downstream ends of all tributaries and various locations along the main stem, showed that a release rate of 0.10 ft3/s-acre, in general, can maintain postdevelopment 100-year peak-flood discharge at a similar magnitude to that of 1996 land-use conditions. Although the release rate is designed to reduce the 100-year peak flow, reduction of the 2-year peak flow is also achieved for a smaller proportion of the peak. Results also showed that the 0.10 ft3/s-acre release rate was less effective in watersheds with relatively high percentages of preexisting (1996) development than in watersheds with less preexisting development.

[Effect on iron release in drinking water distribution systems].

PubMed

Niu, Zhang-bin; Wang, Yang; Zhang, Xiao-jian; Chen, Chao; Wang, Sheng-hui

2007-10-01

Batch-scale experiments were done to quantitatively study the effect of inorganic chemical parameters on iron release in drinking water distribution systems. The parameters include acid-base condition, oxidation-reduction condition, and neutral ion condition. It was found that the iron release rate decreased with pH, alkalinity, the concentration of dissolved oxygen increasing, and the iron release rate increased with the concentration of chloride increasing. The theoretical critical formula of iron release rate was elucidated. According to the formula, the necessary condition for controlling iron release is that pH is above 7.6, the concentration of alkalinity and dissolved oxygen is more than 150 mg/L and 2 mg/L, and the concentration of chloride is less than 150 mg/L of distributed water.

How microglia kill neurons.

PubMed

Brown, Guy C; Vilalta, Anna

2015-12-02

Microglia are resident brain macrophages that become inflammatory activated in most brain pathologies. Microglia normally protect neurons, but may accidentally kill neurons when attempting to limit infections or damage, and this may be more common with degenerative disease as there was no significant selection pressure on the aged brain in the past. A number of mechanisms by which activated microglia kill neurons have been identified, including: (i) stimulation of the phagocyte NADPH oxidase (PHOX) to produce superoxide and derivative oxidants, (ii) expression of inducible nitric oxide synthase (iNOS) producing NO and derivative oxidants, (iii) release of glutamate and glutaminase, (iv) release of TNFα, (v) release of cathepsin B, (vi) phagocytosis of stressed neurons, and (vii) decreased release of nutritive BDNF and IGF-1. PHOX stimulation contributes to microglial activation, but is not directly neurotoxic unless NO is present. NO is normally neuroprotective, but can react with superoxide to produce neurotoxic peroxynitrite, or in the presence of hypoxia inhibit mitochondrial respiration. Glutamate can be released by glia or neurons, but is neurotoxic only if the neurons are depolarised, for example as a result of mitochondrial inhibition. TNFα is normally neuroprotective, but can become toxic if caspase-8 or NF-κB activation are inhibited. If the above mechanisms do not kill neurons, they may still stress the neurons sufficiently to make them susceptible to phagocytosis by activated microglia. We review here whether microglial killing of neurons is an artefact, makes evolutionary sense or contributes in common neuropathologies and by what mechanisms. This article is part of a Special Issue entitled SI: Neuroprotection. Copyright © 2015 Elsevier B.V. All rights reserved.

Notice of Changes to the Weekly Natural Gas Storage Report

EIA Publications

2015-01-01

On November 19, 2015, EIA will release the Weekly Natural Gas Storage Report (WNGSR) with new data breakouts for five regions of the Lower 48 states, converting from the current three-region structure. On Monday, November 16, 2015, EIA will re-release the data that will be published on Friday, November 13 (for the week ending Friday, November 6) in the new five-region format. The release will be conducted through the same timed countdown procedures used for normal releases on the same WNGSR web page: http://ir.eia.gov/ngs/ngs.html.

Impaired mitochondrial pyruvate importation in a patient and a fetus at risk.

PubMed

Brivet, M; Garcia-Cazorla, A; Lyonnet, S; Dumez, Y; Nassogne, M C; Slama, A; Boutron, A; Touati, G; Legrand, A; Saudubray, J M

2003-03-01

The patient was the first child of healthy consanguineous parents. She presented at birth with hypotonia, mild facial dysmorphism, periventricular cysts, marked metabolic acidosis, hyperlactacidemia with normal lactate/pyruvate molar ratios, normoglycemia, and normal ammonia. Hyperlactacidemia was severe (5-14 mmol/l) and not corrected with bicarbonate, thiamine (10 mg/d), 2-chloropropionate (100 mg/kg/d) and a ketogenic diet. Pyruvate dehydrogenase (PDHC) activity was normal in lymphocytes and fibroblasts. Functional assays were performed in digitonin-permeabilized fibroblasts to measure oxidation rates from radiolabeled pyruvate and malate. The production of [14C]acetylcarnitine or [14C]citric cycle intermediates derived from [2-14C]pyruvate as well as the release of 14CO(2) from [1-14C]pyruvate was severely impaired, whereas decarboxylation of [U-14C]malate was normal. With increasing concentrations of [1-14C]pyruvate, the patient's fibroblasts behave like control fibroblasts incubated in the presence of alpha-cyano-4-hydroxycinnamate, a specific inhibitor of mitochondrial pyruvate uptake: a progressive increase in 14CO(2) production was observed, likely due to passive diffusion of [1-14C]pyruvate through the mitochondrial membranes. Our results are consistent with a defect of mitochondrial pyruvate transport in the patient. Mutational analysis was precluded as the cDNA sequence of the pyruvate carrier has not been identified as yet in any organism. An affected fetus was recognized in a subsequent dichorionic twin pregnancy using the coupled assay measuring [2-14C]pyruvate oxidation rates on digitonin-permeabilized trophoblasts. After selective feticide, the pregnancy was uncomplicated with delivery at 37w of a healthy female, who is currently 2-month old. Copyright 2003 Elsevier Science (USA)

Wax-based sustained release matrix pellets prepared by a novel freeze pelletization technique II. In vitro drug release studies and release mechanisms.

PubMed

Cheboyina, Sreekhar; Wyandt, Christy M

2008-07-09

A novel freeze pelletization technique was evaluated for the preparation of wax-based sustained release matrix pellets. Pellets containing water-soluble drugs were successfully prepared using a variety of waxes. The drug release significantly depended on the wax type used and the aqueous drug solubility. The drug release decreased as the hydrophobicity of wax increased and the drug release increased as the aqueous drug solubility increased. In glyceryl monostearate (GMS) pellets, drug release rate decreased as the loading of theophylline increased. On the contrary, the release rate increased as the drug loading of diltiazem HCl increased in Precirol pellets. Theophylline at low drug loads existed in a dissolved state in GMS pellets and the release followed desorption kinetics. At higher loads, theophylline existed in a crystalline state and the release followed dissolution-controlled constant release for all the waxes studied. However, with the addition of increasing amounts of Brij 76, theophylline release rate increased and the release mechanism shifted to diffusion-controlled square root time kinetics. But the release of diltiazem HCl from Precirol pellets at all drug loads, followed diffusion-controlled square root time kinetics. Therefore, pellets capable of providing a variety of release profiles for different drugs can be prepared using this freeze pelletization technique by suitably modifying the pellet forming matrix compositions.

Release kinetics of vanadium from vanadium (III, IV and V) oxides: Effect of pH, temperature and oxide dose.

PubMed

Hu, Xingyun; Yue, Yuyan; Peng, Xianjia

2018-05-01

Batch experiments were performed to derive the rate laws for the proton-promoted dissolution of the main vanadium (III, IV and V) oxides at pH 3.1-10.0. The release rates of vanadium are closely related to the aqueous pH, and several obvious differences were observed in the release behavior of vanadium from the dissolution of V 2 O 5 and vanadium(III, IV) oxides. In the first 2hr, the release rates of vanadium from V 2 O 3 were r=1.14·([H + ]) 0.269 at pH 3.0-6.0 and r=0.016·([H + ]) -0.048 at pH 6.0-10.0; the release rates from VO 2 were r=0.362·([H + ]) 0.129 at pH 3.0-6.0 and r=0.017·([H + ]) -0.097 at pH 6.0-10.0; and the release rates from V 2 O 5 were r=0.131·([H + ]) -0.104 at pH 3.1-10.0. The release rates of vanadium from the three oxides increased with increasing temperature, and the effect of temperature was different at pH 3.8, pH 6.0 and pH 7.7. The activation energies of vanadium (III, IV and V) oxides (33.4-87.5kJ/mol) were determined at pH 3.8, pH6.0 and pH 7.7, showing that the release of vanadium from dissolution of vanadium oxides follows a surface-controlled reaction mechanism. The release rates of vanadium increased with increasing vanadium oxides dose, albeit not proportionally. This study, as part of a broader study of the release behavior of vanadium, can help to elucidate the pollution problem of vanadium and to clarify the fate of vanadium in the environment. Copyright © 2017. Published by Elsevier B.V.

Neuropeptides linking the control of appetite with reproductive function in domestic animals

USDA-ARS?s Scientific Manuscript database

The occurrence of puberty and maintenance of normal reproductive cycles are regulated by secretion of gonadotropin hormones from the pituitary gland, which is dependent upon the pulsatile release of gonadotropin-releasing hormone (GnRH) from the hypothalamus. It is well established that secretion of...

Biophysical and Biochemical Mechanisms in Synaptic Transmitter Release.

DTIC Science & Technology

1992-01-31

vesicle is normally released per active zone Sci USA 83. 3032 (1986) pared (15, 19, 20). In fact, in squid, the quantum 8 0 Shimomura 8 Musicki. V Kisni...8217, AND R. LLINAS• *Instituto de Biologia Celular Facultad de Medicina. Universidad de Buenos Aires. Paraguay 2155. Buenos Aires 1121. Argentina: and

Toward a Mechanistic Source Term in Advanced Reactors: Characterization of Radionuclide Transport and Retention in a Sodium Cooled Fast Reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brunett, Acacia J.; Bucknor, Matthew; Grabaskas, David

A vital component of the U.S. reactor licensing process is an integrated safety analysis in which a source term representing the release of radionuclides during normal operation and accident sequences is analyzed. Historically, source term analyses have utilized bounding, deterministic assumptions regarding radionuclide release. However, advancements in technical capabilities and the knowledge state have enabled the development of more realistic and best-estimate retention and release models such that a mechanistic source term assessment can be expected to be a required component of future licensing of advanced reactors. Recently, as part of a Regulatory Technology Development Plan effort for sodium cooledmore » fast reactors (SFRs), Argonne National Laboratory has investigated the current state of knowledge of potential source terms in an SFR via an extensive review of previous domestic experiments, accidents, and operation. As part of this work, the significant sources and transport processes of radionuclides in an SFR have been identified and characterized. This effort examines all stages of release and source term evolution, beginning with release from the fuel pin and ending with retention in containment. Radionuclide sources considered in this effort include releases originating both in-vessel (e.g. in-core fuel, primary sodium, cover gas cleanup system, etc.) and ex-vessel (e.g. spent fuel storage, handling, and movement). Releases resulting from a primary sodium fire are also considered as a potential source. For each release group, dominant transport phenomena are identified and qualitatively discussed. The key product of this effort was the development of concise, inclusive diagrams that illustrate the release and retention mechanisms at a high level, where unique schematics have been developed for in-vessel, ex-vessel and sodium fire releases. This review effort has also found that despite the substantial range of phenomena affecting radionuclide release, the current state of knowledge is extensive, and in most areas may be sufficient. Several knowledge gaps were identified, such as uncertainty in release from molten fuel and availability of thermodynamic data for lanthanides and actinides in liquid sodium. However, the overall findings suggest that high retention rates can be expected within the fuel and primary sodium for all radionuclides other than noble gases.« less

A MODEL FOR FISSION-GAS RELEASE FROM POROUS FUELS IN LOW-PERMEABILITY CONTAINERS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prados, J.W.

1961-08-25

A simple mathematical model was developed to describe the steady-state release rate of gaseous fission products from porous ceramic fuels in low- permeability containers. The resulting equations are used to analyze experimental release rate results obtained from a UC/sub 2/-fueled graphite fuel body enclosed in a low-permeability impregnated graphite container. The relative release rates of the fission-product species Kr/sup 85m/, Kr/sup 88/, and Xe/sup 133/ were predicted with reasonable success. Absolute-rate predictions were not possible due to lack of information on true permeability and porosity profiles in the graphite container. (auth)

Diffusion Performance of Fertilizer Nutrient through Polymer Latex Film.

PubMed

An, Di; Yang, Ling; Liu, Boyang; Wang, Ting-Jie; Kan, Chengyou

2017-12-20

Matching the nutrient release rate of coated fertilizer with the nutrient uptake rate of the crop is the best way to increase the utilization efficiency of nutrients and reduce environmental pollution from the fertilizer. The diffusion property and mechanism of nutrients through the film are the theoretical basis for the product pattern design of coated fertilizers. For the coated fertilizer with a single-component nutrient, an extended solution-diffusion model was used to describe the difference of nutrient release rate, and the release rate is proportional to the permeation coefficient and the solubility of the nutrient. For the double- and triple-component fertilizer of N-K, N-P, and N-P-K, because of the interaction among nutrient molecules and ions, the release rates of different nutrients were significantly affected by the components in the composite fertilizer. Coating the single-component fertilizer (i.e., nitrogen fertilizer, phosphate fertilizer, and potash fertilizer) first and subsequently bulk blending is expected to be a promising way to adjust flexibly the nutrient release rate to meet the nutrient uptake rate of the crop.

Field evaluation of plant odor and pheromonal combinations for attracting plum curculios.

PubMed

Piñero, Jaime C; Prokopy, Ronald J

2003-12-01

The attractiveness of different synthetic host odors and a synthetic aggregation pheromone (grandisoic acid [GA]) to overwintered adult plum curculios (PCs), Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae), was examined using two types of traps (sticky panels and black pyramids) placed in border areas surrounding an unsprayed section of an apple orchard in Massachusetts. In 2001, we evaluated the response of PCs to three synthetic fruit volatiles (benzaldehyde [BEN], ethyl isovalerate [EIV], and limonene [LIM]) assessed alone and in combination with GA, as well as the response to GA alone and a no-odor (control) treatment. BEN was the only host volatile that synergized the response of PCs to GA for both trap types. For both trap types, GA was as attractive to PCs as a single component as when in combination with either EIV or LIM. In 2002, four release rates of BEN (0, 2.5, 10, and 40 mg/day) and two release rates of GA (1 and 2 mg/day) were evaluated for attractiveness to PCs using panel and pyramid traps. For panel traps, an increase in amount of GA released (from 1 to 2 mg/day) was associated with a 35% increase in captures. However, PC captures by pyramid traps were similar regardless of the amount of GA released. For panel traps, 10 and 40 mg/day of BEN were the most attractive release rates regardless of the amount of GA released. For pyramid traps baited with GA. PC captures were enhanced by the presence of BEN, regardless of release rate. In 2003, GA at 1 mg/day + BEN at 80 mg/day of release did not enhance PC captures by panel traps relative to lower release rates of BEN. Pyramid traps releasing GA at 1 mg/day performed best when baited with BEN at 10 mg/day of release; a release rate of 80 mg/day of BEN decreased the attractiveness of the binary combination of BEN + GA. Combined results suggest that BEN at 10 mg/day + GA at 1 mg/day of release constitutes an attractive lure that may improve the effectiveness of monitoring traps for PCs.

On the shock response of PCTFE (Kel-F 81¯)

NASA Astrophysics Data System (ADS)

Wood, D. C.; Appleby-Thomas, G. J.; Fitzmaurice, B. C.; Hameed, A.; Millett, J. C. F.; Hazell, P. J.

2017-01-01

The polymeric material PCTFE (Kel-F 81®) has found a useful niche in explosive research due to its use not only an explosive binder but also as a explosive simulant. Knowledge of shock propagation in explosives is of paramount importance primarily from a safety perspective both in terms of reaction to a designed stimulus and to off-normal (accident) events. To this end, as part of a more general investigation into the relationship between polymeric structure and high strain-rate response, the dynamic response of PCFTE (more commonly known as Kel-F 81®) has been investigated via a series of plate-impact experiments. Using this technique both the shock and release behaviour of PCTFE have been investigated. The data obtained for the shock response agreed with previously obtained data from the literature. Deviation from the Hugoniot was seen in the pressure-particle velocity plane, a response attributed here to material strength. With regards to the behaviour of the release Hugoniot, a two-tiered response was observed. Initially a tensile elastic wave with an approximate velocity of 3.00 mm μs-1 was noted until a particle velocity of 0.36 mm μs-1. After this initial region a linear release Hugoniot was apparent, a response comparable to behaviour seen in other polymers.

Prolonged cytotoxic effect of colchicine released from biodegradable microspheres.

PubMed

Muvaffak, Asli; Gurhan, Ismet; Hasirci, Nesrin

2004-11-15

One the main problems of cancer chemotherapy is the unwanted damage to normal cells caused by the high toxicities of anticancer drugs. Any system of controlled drug delivery that would reduce the total amount of drug required, and thus reduce the side effects, would potentially help to improve chemotherapy. In this respect, biodegradable gelatin microspheres were prepared by water/oil emulsion polymerization and by crosslinking with glutaraldehyde (GTA) as the drug-carrier system. Microspheres were loaded with colchicine, a model antimitotic drug, which was frequently used as an antimitotic agent in cancer research involving cell cultures. Microsphere sizes, swelling and degradation properties, drug-release kinetics, and cytotoxities were studied. Swelling characteristics of microspheres changed upon changing GTA concentration. A decrease in swelling values was recorded as GTA crosslink density was increased. In vitro drug release in PBS (0.01M, pH 7.4) showed rapid colchicine release up to approximately 83% (at t = 92 h) for microspheres with low GTA (0.05% v/v), whereas a slower release profile (only approximately 39%) was obtained for microspheres with high GTA (0.50% v/v) content, for the same period. Cytotoxicity tests with MCF-7, HeLa and H-82 cancer cell lines showed that free colchicine was very toxic, showing an approximately 100% lethal effect in both HeLa and H-82 cell lines and more than 50% decrease in viability in MCF-7 cells in 4 days. Indeed, entrapped colchicine indicated similar initial high toxic effect on cell viability in MCF-7 cell line and this effect became more dominant as colchicine continued to be released from microspheres in the same period. In conclusion, the control of the release rate of colchicine from gelatin microspheres was achieved under in vitro conditions by gelatin through the alteration of crosslinking conditions. Indeed, the results suggested the potential application of gelatin microspheres crosslinked with GTA as a sustained drug-delivery system for anticancer drugs for local chemotherapy administrations. (c) 2004 Wiley Periodicals, Inc.

Ferulic Acid-Based Polymers with Glycol Functionality as a Versatile Platform for Topical Applications.

PubMed

Ouimet, Michelle A; Faig, Jonathan J; Yu, Weiling; Uhrich, Kathryn E

2015-09-14

Ferulic acid-based polymers with aliphatic linkages have been previously synthesized via solution polymerization methods, yet they feature relatively slow ferulic acid release rates (∼11 months to 100% completion). To achieve a more rapid release rate as required in skin care formulations, ferulic acid-based polymers with ethylene glycol linkers were prepared to increase hydrophilicity and, in turn, increase ferulic acid release rates. The polymers were characterized using nuclear magnetic resonance and Fourier transform infrared spectroscopies to confirm chemical composition. The molecular weights, thermal properties (e.g., glass transition temperature), and contact angles were also obtained and the polymers compared. Polymer glass transition temperature was observed to decrease with increasing linker molecule length, whereas increasing oxygen content decreased polymer contact angle. The polymers' chemical structures and physical properties were shown to influence ferulic acid release rates and antioxidant activity. In all polymers, ferulic acid release was achieved with no bioactive decomposition. These polymers demonstrate the ability to strategically release ferulic acid at rates and concentrations relevant for topical applications such as skin care products.

Convenient method of establishing permanent lines of xeroderma pigmentosum cells. [Ultraviolet radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tohda, H.; Oikawa, A.; Katsuki, T.

Nine lymphoblastoid cell lines were established after transformation by Epstein-Barr virus of peripheral lymphocytes from four xeroderma pigmentosum (XP) patients, the parents of one XP patient, and three normal donors. All these cell lines proliferate as suspension in Roswell Park Memorial Institute Medium 1640 supplemented with 20% fetal bovine serum, without detectable release of infectious Epstein-Barr virus. Some characteristics of these cell lines, such as growth rates, chromosome numbers, uv sensitivities, and activities of unscheduled DNA syntheses induced by uv, 4-nitroquinoline 1-oxide, and N-methyl-N'-nitro-N-nitrosoguanidine, were determined. Results confirm that the properties related to XP are not altered by transformation withmore » Epstein-Barr virus and are the same in degrees of defect as are those of dermal fibroblasts from the respective individuals. These XP and normal lymphoblastoid cell lines should be especially useful for biochemical studies on the mechanism of DNA repair, because they are easy to grow in mass culture.« less

Superconducting thermal neutron detectors

NASA Astrophysics Data System (ADS)

Merlo, V.; Pietropaolo, A.; Celentano, G.; Cirillo, M.; Lucci, M.; Ottaviani, I.; Salvato, M.; Scherillo, A.; Schooneveld, E. M.; Vannozzi, A.

2016-09-01

A neutron detection concept is presented that is based on superconductive niobium nitride (NbN) strips coated by a boron (B) layer. The working principle is well described by a hot spot mechanism: upon the occurrence of the nuclear reactions n + 10B → α + 7Li + 2.8 MeV, the energy released by the secondary particles into the strip induces a superconducting-normal state transition. The latter is recognized as a voltage signal which is the evidence of the incident neutron. The above described detection principle has been experimentally assessed and verified by irradiating the samples with a pulsed neutron beam at the ISIS spallation neutron source (UK). It is found that the boron coated superconducting strips, kept at a temperature T below 11K and current-biased below the critical current IC, are driven into the normal state upon thermal neutron irradiation. Measurements on the counting rate of the device are presented and the basic physical features of the detector are discussed and compared to those of a borated Nb superconducting strip.

Comparative drug release measurements in limited amounts of liquid: a suppository formulation study.

PubMed

Welch, Ken; Ek, Ragnar; Strømme, Maria

2006-07-01

A novel method for the investigation of drug formulations in limited liquid volumes is presented. The experimental setup consists of a measurement cell containing an absorbent sponge cloth placed between two parallel electrodes. Conductivity measurements are used to monitor the drug release from the dosage form. By varying the amount of water contained in the absorbent cloth surrounding the dosage form, it is possible to measure the drug release performance of the dosage form in very limited amounts of water. The method was employed to test four different tablet formulations consisting of the model drug NaCl incorporated in excipient matrices of hard fat, polyethylene glycol, microcrystalline cellulose and a mixture of microcrystalline cellulose and croscarmellose sodium (Ac-Di-Sol). The drug release rates of the different formulations in limited water volumes differed markedly from the release rates in an excess of water. Whereas the release rates from all tablet types in an excess of water showed only minor differences among the tablet types, the release rates from the tablets formulated with disintegrating excipients were clearly superior in limited water volumes. The developed method for drug release in limited volumes of liquid should be suitable for evaluation of rectal dosage forms.

Tau Kinetics in Neurons and the Human Central Nervous System.

PubMed

Sato, Chihiro; Barthélemy, Nicolas R; Mawuenyega, Kwasi G; Patterson, Bruce W; Gordon, Brian A; Jockel-Balsarotti, Jennifer; Sullivan, Melissa; Crisp, Matthew J; Kasten, Tom; Kirmess, Kristopher M; Kanaan, Nicholas M; Yarasheski, Kevin E; Baker-Nigh, Alaina; Benzinger, Tammie L S; Miller, Timothy M; Karch, Celeste M; Bateman, Randall J

2018-03-21

We developed stable isotope labeling and mass spectrometry approaches to measure the kinetics of multiple isoforms and fragments of tau in the human central nervous system (CNS) and in human induced pluripotent stem cell (iPSC)-derived neurons. Newly synthesized tau is truncated and released from human neurons in 3 days. Although most tau proteins have similar turnover, 4R tau isoforms and phosphorylated forms of tau exhibit faster turnover rates, suggesting unique processing of these forms that may have independent biological activities. The half-life of tau in control human iPSC-derived neurons is 6.74 ± 0.45 days and in human CNS is 23 ± 6.4 days. In cognitively normal and Alzheimer's disease participants, the production rate of tau positively correlates with the amount of amyloid plaques, indicating a biological link between amyloid plaques and tau physiology. Copyright © 2018 Elsevier Inc. All rights reserved.

Surface charge-switchable polymeric magnetic nanoparticles for the controlled release of anticancer drug.

PubMed

Shen, Jian-Min; Yin, Tao; Tian, Xiao-Zhu; Gao, Fei-Yun; Xu, Shuang

2013-08-14

We develop paclitaxel (PTX) and magnetic nanoparticles (MNPs) coencapsulated, surface charge-switchable, thermosensitive poly(d,l-lactic-co-glycolic acid)-l-lysine-d-galactose (PTX-MNP-PLGA-Lys-Gal) NPs for the controlled release of the anticancer drug. The novel dual signal-responsive nanovehicle is formulated to shield off target at pH 7.4 but bind avidly to tumor cells in acidity, alleviating toxicity and side effects of the drug to normal tissues. The mechanism involves pH-sensitive NPs surface charge switching by the deblocking process of galactose molecules followed by protonation of ε-NH2 in lysine residue at acidic pH. Magnetic hyperthermia under near infrared (NIR) irradiation induced the contraction of PTX-MNP-PLGA-Lys-Gal NPs and, in turn, triggered burst release of PTX. Transmission electron microscopy (TEM), fluorescence microscope analyses, Fourier transform infrared (FTIR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), dynamic light scattering (DLS), and ξ-potential analyses were performed to characterize physicochemical properties of the as-prepared NPs. The size range of the globule PTX-MNP-PLGA-Lys-Gal NPs after being prescreened was from 130 to 150 nm under simulated physiological medium. The high encapsulation efficiencies of MNPs and PTX were obtained, reaching 85 and 78 wt % for PTX-MNP-PLGA-Lys-Gal NPs, respectively. The tumor inhibitory rate of 78.8% reflected that the resulting NPs could be promising to treat cancer by specific binding and targeting release drug to tumor.

Low-molecular-weight organoiodine and organobromine compounds released by polar macroalgae--the influence of abiotic factors.

PubMed

Laturnus, F; Giese, B; Wiencke, C; Adams, F C

2000-01-01

The influence of temperature, light, salinity and nutrient availability on the release of volatile halogenated hydrocarbons was investigated in the Antarctic red macroalgal species Gymnogongrus antarcticus Skottsberg. Compared to standard culture condition, an increase in the release rates of iodocompounds was generally found for the exposure of the alga to altered environmental conditions. Macroalgae exhibited higher release rates after adaptation for two months to the changed factors, than after short-term exposure. Monitoring the release rates during a 24 h incubation period (8.25 h light, 15.75 h darkness) showed that changes between light and dark periods had no influence on the release of volatile halocarbons. Compounds like bromoform and 1-iodobutane exhibited constant release rates during the 24 h period. The formation mechanisms and biological role of volatile organohalogens are discussed. Although marine macroalgae are not considered to be the major source of biogenically-produced volatile organohalogens, they contribute significantly to the bromine and iodine cycles in the environment. Under possible environmental changes like global warming and uncontrolled entrophication of the oceans their significance may be increase.

Surveillance of Diversion and Nonmedical Use of Extended-Release Prescription Amphetamine and Oral Methylphenidate in the United States

PubMed Central

Sembower, Mark A.; Ertischek, Michelle D.; Buchholtz, Chloe; Dasgupta, Nabarun; Schnoll, Sidney H.

2013-01-01

This article examines rates of nonmedical use and diversion of extended-release amphetamine and extended-release oral methylphenidate in the United States. Prescription dispensing data were sourced from retail pharmacies. Nonmedical use data were collected from the Researched Abuse, Diversion and Addiction-Related Surveillance (RADARS) System Drug Diversion Program and Poison Center Program. Drug diversion trends nearly overlapped for extended-release amphetamine and extended-release oral methylphenidate. Calls to poison centers were generally similar; however, calls regarding extended-release amphetamine trended slightly lower than those for extended-release oral methylphenidate. Data suggest similar diversion and poison center call rates for extended-release amphetamine and extended-release oral methylphenidate. PMID:23480245

Estimations of direct release rate of 137Cs and 90Sr to the ocean from the Fukushima Dai-ichi Nuclear Power Plant for five-and-a-half years

NASA Astrophysics Data System (ADS)

Tsumune, Daisuke; Aoyama, Michio; Tsubono, Takaki; Misumi, Kazuhiro; Tateda, Yutaka

2017-04-01

A series of accidents at the Fukushima Dai-ichi Nuclear Power Plant (1F NPP) following the earthquake and tsunami of 11 March 2011 resulted in the release of radioactive materials to the ocean by two major pathways, direct release from the accident site and atmospheric deposition. Additional release pathways by river input and runoff from 1F NPP site with precipitation and were also effective for coastal zone in the specific periods before starting direct release on March 26 2011. Direct release from 1F NPP site is dominant one year after the accident. We estimated the direct release rate of 137Cs and 90Sr for more than five-and-a-half years after the accident by the Regional Ocean Model System (ROMS). Direct release rate of 137Cs were estimated for five-and-a-half years after the accident by comparing simulated results and measured activities adjacent to the 1F NPP site(at 5,6 discharge and south discharge). Directly release rate of 137Cs was estimated to be the order of magnitude of 1014 Bq/day and decreased exponentially with time to be the order of magnitude of 109 Bq/day by the end of September 2016. Estimated direct release rate have exponentially reduced with constant rate since November 2011. Apparent half-life of direct release rate was estimated to be 346 days. The estimated total amounts of directly released 137Cs was 3.7±0.7 PBq for five and a half years. Simulated 137Cs activities attributable to direct release were in good agreement with observed activities, a result that implies the estimated direct release rate was reasonable. Simulated 137Cs activity affected off coast in the Fukushima prefecture. We used the measured 137Cs activities by the Tokyo Electric Power Company (TEPCO) for the estimation of direct release. The sea water samples were corrected from the coast. The averaged 137Cs activities from November 2013 to June 2016 were 391 and 383 Bq/m3 at 5,6 discharge and south discharge, respectively. The averaged 137Cs activities measured by the Nuclear Regulation Agency (NRA) is about five times smaller than the one by the TEPCO because the NRA corrected seawater samples at 300-500m offshore by ship. Horizontal resolution of the model was 1km x 1km, therefore it is important to consider the difference of activities in the sub-grid scale for the detailed estimations of direct release. 90Sr/137Cs activity ratio measured adjacent to the 1F NPP is variable with time. The 90Sr/137Cs activity ratio was 0.62 due to the global fallout before the accident. The 90Sr/137Cs activity ratio decreased to 0.01 after the accident before April 2011. And the ratio increased to 1 by September 2013. And then the ratio decreased to 0.1-1. After October 2015, the ratio decreased to 0.1-0.2. Directly release rate of 90Sr was estimated to be the order of magnitude of 1012 Bq/day and decreased to the order of magnitude of 108 Bq/day by the end of September 2016. The estimated total amounts of directly released 90Sr was 35 ± 7 TBq.

Insulin production rate in normal man as an estimate for calibration of continuous intravenous insulin infusion in insulin-dependent diabetic patients.

PubMed

Waldhäusl, W K; Bratusch-Marrain, P R; Francesconi, M; Nowotny, P; Kiss, A

1982-01-01

This study examines the feasibility of deriving the 24-h insulin requirement of insulin-dependent diabetic patients who were devoid of any endogenous insulin release (IDD) from the insulin-production rate (IPR) of healthy man (basal, 17 mU/min; stimulated 1.35 U/12.5 g glucose). To this end, continuous intravenous insulin infusion (CIVII) was initiated at a precalculated rate of 41.2 +/- 4.6 (SD) U/24 h in IDD (N - 12). Blood glucose profiles were compared with those obtained during intermittent subcutaneous (s.c.) insulin therapy (IIT) and those of healthy controls (N = 7). Regular insulin (Hoechst CS) was infused with an adapted Mill Hill Infuser at a basal infusion rate of 1.6 U/h (6:00 a.m. to 8:00 p.m.), and of 0.8 U/h from 8:00 p.m. to 6:00 a.m. Preprandial insulin (3.2-6.4 U) was added for breakfast, lunch, and dinner. Daily individual food intake totaled 7688 +/- 784 kJ (1836 +/- 187 kcal)/24 h including 184 +/- 37 g of glucose. Proper control of blood glucose (BG) (mean BG 105 +/- 10 mg/dl; mean amplitude of glycemic excursions 54 +/- 18 mg/dl; and 1 h postprandial BG levels not exceeding 160 mg/dl) and of plasma concentrations of beta-hydroxybutyrate and lactate was maintained by 41.4 +/- 4.4 U insulin/24 h. Although BG values only approximated the upper normal range as seen in healthy controls, they were well within the range reported by others during CIVII. Therefore, we conclude that in adult IDD completely devoid of endogenous insulin (1) the IPR of normal man can be used during CIVII as an estimate for the patient's minimal insulin requirement per 24 h, and (2) this approach allows for a blood glucose profile close to the upper range of a normal control group. Thus, deriving a patient's daily insulin dose from the insulin production rate of healthy man may add an additional experimental protocol which aids in making general calculations of a necessary insulin dose instead of using trial and error or a closed-loop insulin infusion system.

Capsaicin-evoked iCGRP release from human dental pulp: a model system for the study of peripheral neuropeptide secretion in normal healthy tissue

PubMed Central

Fehrenbacher, Jill C.; Sun, Xiaoling X.; Locke, Erin E.; Henry, Michael A.; Hargreaves, Kenneth M.

2009-01-01

The mechanisms underlying trigeminal pain conditions are incompletely understood. In vitro animal studies have elucidated various targets for pharmacological intervention; however, a lack of clinical models that allow evaluation of viable innervated human tissue has impeded successful translation of many preclinical findings into clinical therapeutics. Therefore, we developed and characterized an in vitro method that evaluates the responsiveness of isolated human nociceptors by measuring basal and stimulated release of neuropeptides from collected dental pulp biopsies. Informed consent was obtained from patients presenting for extraction of normal wisdom teeth. Patients were anesthetized using nerve block injection, teeth were extracted and bisected, and pulp was removed and superfused in vitro. Basal and capsaicin-evoked peripheral release of immunoreactive calcitonin gene-related peptide (iCGRP) was analyzed by enzyme immunoassay. The presence of nociceptive markers within neurons of the dental pulp was characterized using confocal microscopy. Capsaicin increased the release of iCGRP from dental pulp biopsies in a concentration-dependent manner. Stimulated release was dependent on extracellular calcium, reversed by a TRPV1 receptor antagonist, and desensitized acutely (tachyphylaxis) and pharmacologically by pretreatment with capsaicin. Superfusion with phorbol 12-myristate 13-acetate (PMA) increased basal and stimulated release, whereas PGE2 augmented only basal release. Compared with vehicle treatment, pretreatment with PGE2 induced competence for DAMGO to inhibit capsaicin-stimulated iCGRP release, similar to observations in animal models where inflammatory mediators induce competence for opioid inhibition. These results indicate the release of iCGRP from human dental pulp provides a novel tool to determine the effects of pharmacological compounds on human nociceptor sensitivity. PMID:19428185

Evaluating the combined effects of source zone mass release rates and aquifer heterogeneity on solute discharge uncertainty

NASA Astrophysics Data System (ADS)

de Barros, Felipe P. J.

2018-07-01

Quantifying the uncertainty in solute mass discharge at an environmentally sensitive location is key to assess the risks due to groundwater contamination. Solute mass fluxes are strongly affected by the spatial variability of hydrogeological properties as well as release conditions at the source zone. This paper provides a methodological framework to investigate the interaction between the ubiquitous heterogeneity of the hydraulic conductivity and the mass release rate at the source zone on the uncertainty of mass discharge. Through the use of perturbation theory, we derive analytical and semi-analytical expressions for the statistics of the solute mass discharge at a control plane in a three-dimensional aquifer while accounting for the solute mass release rates at the source. The derived solutions are limited to aquifers displaying low-to-mild heterogeneity. Results illustrate the significance of the source zone mass release rate in controlling the mass discharge uncertainty. The relative importance of the mass release rate on the mean solute discharge depends on the distance between the source and the control plane. On the other hand, we find that the solute release rate at the source zone has a strong impact on the variance of the mass discharge. Within a risk context, we also compute the peak mean discharge as a function of the parameters governing the spatial heterogeneity of the hydraulic conductivity field and mass release rates at the source zone. The proposed physically-based framework is application-oriented, computationally efficient and capable of propagating uncertainty from different parameters onto risk metrics. Furthermore, it can be used for preliminary screening purposes to guide site managers to perform system-level sensitivity analysis and better allocate resources.

Magnesium substitution in the structure of orthopedic nanoparticles: A comparison between amorphous magnesium phosphates, calcium magnesium phosphates, and hydroxyapatites.

PubMed

Nabiyouni, Maryam; Ren, Yufu; Bhaduri, Sarit B

2015-01-01

As biocompatible materials, magnesium phosphates have received a lot of attention for orthopedic applications. During the last decade multiple studies have shown advantages for magnesium phosphate such as lack of cytotoxicity, biocompatibility, strong mechanical properties, and high biodegradability. The present study investigates the role of Mg(+2) and Ca(+2) ions in the structure of magnesium phosphate and calcium phosphate nanoparticles. To directly compare the effect of Mg(+2) and Ca(+2) ions on structure of nanoparticles and their biological behavior, three groups of nanoparticles including amorphous magnesium phosphates (AMPs) which release Mg(+2), calcium magnesium phosphates (CMPs) which release Mg(+2) and Ca(+2), and hydroxyapatites (HAs) which release Ca(+2) were studied. SEM, TEM, XRD, and FTIR were used to evaluate the morphology, crystallinity, and chemical properties of the particles. AMP particles were homogeneous nanospheres, whereas CMPs were combinations of heterogeneous nanorods and nanospheres, and HAs which contained heterogeneous nanosphere particles. Cell compatibility was monitored in all groups to determine the cytotoxicity effect of particles on studied MC3T3-E1 preosteoblasts. AMPs showed significantly higher attachment rate than the HAs after 1 day and both AMPs and CMPs showed significantly higher proliferation rate when compared to HAs after 7days. Gene expression level of osteoblastic markers ALP, COL I, OCN, OPN, RUNX2 were monitored and they were normalized to GAPDH housekeeping gene. Beta actin expression level was monitored as the second housekeeping gene to confirm the accuracy of results. In general, AMPs and CMPs showed higher expression level of osteoblastic genes after 7 days which can further confirm the stimulating role of Mg(+2) and Ca(+2) ions in increasing the proliferation rate, differentiation, and mineralization of MC3T3-E1 preosteoblasts. Copyright © 2015 Elsevier B.V. All rights reserved.

Tibiofemoral contact mechanics following posterior root of medial meniscus tear, repair, meniscectomy, and allograft transplantation.

PubMed

Kim, Jin Goo; Lee, Yong Seuk; Bae, Tae Soo; Ha, Jeong Ku; Lee, Dong Hoon; Kim, Young Jae; Ra, Ho Jong

2013-09-01

The purposes of this study were to evaluate the effect on tibiofemoral contact mechanics of repair of the posterior root of the medial meniscus and the effect of meniscal allograft transplantation (MAT) with medial collateral ligament (MCL) release at different flexion angles. Ten fresh-frozen human cadaveric knees (five pairs) were used. A digital pressure sensor was inserted by capsulotomy, and experiments were performed serially under the following six conditions, that is, with an intact medial meniscus (normal controls), with a root tear, after root repair, after total meniscectomy, after MAT, and after MAT plus MCL release. During each experiment, knees were positioned at 0°, 30°, 60°, and 90° of flexion, and peak pressure (kPa) and contact area (cm2) were measured. At 0° of flexion, contact pressure did not differ among the six experimental settings. However, at 30° and 60° of flexion, contact pressure differed significantly between root tear and root repair specimens (p = 0.04 and 0.03, respectively), and between total meniscectomy and MAT specimens (p = 0.02 and 0.03, respectively). On the other hand, mean contact pressures were different between normal (476.7 ± 473.1 and 573.3 ± 479.1 kPa) and root repair (575.7 ± 357.8 and 598.6 ± 415.8), and between normal and MAT (635.7 ± 437.4 and 674.3 ± 533.2). At 0°, 30°, 60°, and 90° of flexion, contact areas differed significantly between normal and total meniscectomy specimens (p = 0.02, 0.01, 0.02, and 0.02, respectively), and between MAT and total meniscectomy specimens (p = 0.03, 0.02, 0.02, and 0.03, respectively). Contact areas differed significantly between root tear and root repair specimens at 60° of flexion (p = 0.04), and between normal control and root repair specimens at 60° and 90° of flexion (p = 0.03 and 0.04, respectively). The effects of MAT plus MCL release on contact mechanics were not different from the effects of MAT alone (n.s.). Both meniscal root repair and transplantation of meniscus improved contact mechanics, but it did not appear that repair of the meniscal root or transplantation of meniscus restores the biomechanical function back to normal level. The MAT plus MCL release was similar to those after MAT alone. Therefore, it is better to preserve meniscus and MCL release could be done during the MAT.

Solid lipid nanoparticles as carrier for sunscreens: in vitro release and in vivo skin penetration.

PubMed

Wissing, S A; Müller, R H

2002-06-17

The aim of this study was the comparison of two different formulations (solid lipid nanoparticles (SLN) and conventional o/w emulsion) as carrier systems for the molecular sunscreen oxybenzone. The influence of the carrier on the rate of release was studied in vitro with a membrane-free model. The release rate could be decreased by up to 50% with the SLN formulation. Further in vitro measurements with static Franz diffusion cells were performed. In vivo, penetration of oxybenzone into stratum corneum on the forearm was investigated by the tape stripping method. It was shown that the rate of release is strongly dependent upon the formulation and could be decreased by 30-60% in SLN formulations. In all test models, oxybenzone was released and penetrated into human skin more quickly and to a greater extent from the emulsions. The rate of release also depends upon the total concentration of oxybenzone in the formulation. In vitro-in vivo correlations could be made qualitatively.

Sustained release of methotrexate through liquid-crystalline folate nanoparticles.

PubMed

Misra, Rahul; Mohanty, Sanat

2014-09-01

To make chemotherapy more effective, sustained release of the drug is desirable. By controlling the release rates, constant therapeutic levels can be achieved which can avoid re-administration of drug. This helps to combat tumors more effectively with minimal side effects. The present study reports the control release of methotrexate through liquid-crystalline folate nanoparticles. These nanoparticles are composed of highly ordered folate self-assembly which encapsulate methotrexate molecules. These drug molecules can be released in a controlled manner by disrupting this assembly in the environment of monovalent cations. The ordered structure of folate nanoparticles offers low drug losses of about 4-5%, which is significant in itself. This study reports the size-control method of forming methotrexate encapsulated folate nanoparticles as well as the release of methotrexate through these nanoparticles. It has been demonstrated that methotrexate release rates can be controlled by controlling the size of the nanoparticles, cross-linking cation and cross-linking concentration. The effect of different factors like drug loading, release medium, and pH of the medium on methotrexate release rates was also studied.

[Decomposition dynamics of leaf litter in logging residue of a secondary Castanopsis carlesii plantation and its chemical composition changes].

PubMed

Ren, Wei-ling; Guo, Jian-fen; Wu, Bo-bo; Wan, Jing-juan; Ji, Shu-rong; Liu, Xiao-fei

2015-04-01

A field experiment was conducted to understand the decomposition rates and chemical composition changes of leaf litter in logging residues of a 35-year-old secondary Castanopsis carlesii plantation over a period of one year. Mass loss rate of leaf litter showed an exponential decrease with time from May 2012 to April 2013, with a total 80% loss of initial dry mass. Net potassium (K) release was observed during this period, with only 5% of initial K remained. Nitrogen ( N) featured a pattern of accumulation at the early stage and release later, while phosphorus (P) exhibited a sequence of release, accumulation, and release. The remaining of N and P were 19% and 16% of their initial mass, respectively. The release rate was highest for K and the lowest for N. Decomposition of lignin indicated a trend of release-accumulation-release from May 2012 to October 2012, with no further significant change from November 2012 to the end of the experiment. The concentration of cellulose nearly unchanged during the experiment. The N/P rate increased with decomposition, ranging from 18.6 to 21.1. The lignin/N rate fluctuated greatly at the early stage and then almost stabilized thereafter.

Pituitary response to thyrotropin releasing hormone in children with overweight and obesity.

PubMed

Rijks, Jesse; Penders, Bas; Dorenbos, Elke; Straetemans, Saartje; Gerver, Willem-Jan; Vreugdenhil, Anita

2016-08-03

Thyroid stimulating hormone (TSH) concentrations in the high normal range are common in children with overweight and obesity, and associated with increased cardiovascular disease risk. Prior studies aiming at unravelling the mechanisms underlying these high TSH concentrations mainly focused on factors promoting thyrotropin releasing hormone (TRH) production as a cause for high TSH concentrations. However, it is unknown whether TSH release of the pituitary in response to TRH is affected in children with overweight and obesity. Here we describe TSH release of the pituitary in response to exogenous TRH in 73 euthyroid children (39% males) with overweight or (morbid) obesity. Baseline TSH concentrations (0.9-5.5 mU/L) were not associated with BMI z score, whereas these concentrations were positively associated with TSH concentrations 20 minutes after TRH administration (r(2) = 0.484, p < 0.001) and the TSH incremental area under the curve during the TRH stimulation test (r(2) = 0.307, p < 0.001). These results suggest that pituitary TSH release in response to TRH stimulation might be an important factor contributing to high normal serum TSH concentrations, which is a regular finding in children with overweight and obesity. The clinical significance and the intermediate factors contributing to pituitary TSH release need to be elucidated in future studies.

Pituitary response to thyrotropin releasing hormone in children with overweight and obesity

PubMed Central

Rijks, Jesse; Penders, Bas; Dorenbos, Elke; Straetemans, Saartje; Gerver, Willem-Jan; Vreugdenhil, Anita

2016-01-01

Thyroid stimulating hormone (TSH) concentrations in the high normal range are common in children with overweight and obesity, and associated with increased cardiovascular disease risk. Prior studies aiming at unravelling the mechanisms underlying these high TSH concentrations mainly focused on factors promoting thyrotropin releasing hormone (TRH) production as a cause for high TSH concentrations. However, it is unknown whether TSH release of the pituitary in response to TRH is affected in children with overweight and obesity. Here we describe TSH release of the pituitary in response to exogenous TRH in 73 euthyroid children (39% males) with overweight or (morbid) obesity. Baseline TSH concentrations (0.9–5.5 mU/L) were not associated with BMI z score, whereas these concentrations were positively associated with TSH concentrations 20 minutes after TRH administration (r2 = 0.484, p < 0.001) and the TSH incremental area under the curve during the TRH stimulation test (r2 = 0.307, p < 0.001). These results suggest that pituitary TSH release in response to TRH stimulation might be an important factor contributing to high normal serum TSH concentrations, which is a regular finding in children with overweight and obesity. The clinical significance and the intermediate factors contributing to pituitary TSH release need to be elucidated in future studies. PMID:27485208

Astressin B, a corticotropin-releasing hormone receptor antagonist, accelerates the return to normal luteal function after an inflammatory-like stress challenge in the rhesus monkey.

PubMed

Xiao, Ennian; Xia-Zhang, Linna; Vulliemoz, Nicolas; Rivier, Jean; Ferin, Michel

2007-02-01

Endogenous release of CRH in stress has been associated with a dysfunctional reproductive endocrine axis. In the rhesus monkey, an inflammatory-like stress challenge in the luteal phase decreases luteal secretory function. Here, we tested the effectiveness of astressin B, a nonspecific CRH receptor antagonist, in constraining the deleterious impact of a 10-d lipopolysaccharide (LPS) challenge on the menstrual cycle. Two protocols were carried out in nine animals. In the first, the animals, after showing two normal consecutive control cycles, were injected daily for 10 days with LPS (75-125 mug/d) during the luteal phase of the cycle. The animals were followed through the two postchallenge cycles. The second protocol, carried out in the following year, was identical with protocol 1, except that the animals were treated with astressin B (0.45 mg/kg) 1 h before each daily LPS challenge during the luteal phase. Blood samples were obtained daily to document cyclic hormones levels. The LPS challenge significantly decreased luteal progesterone and LH release during the challenge cycle. Inhibition of luteal progesterone extended to the two successive postchallenge cycles. Astressin B treatment prevented luteal LH but not luteal progesterone decrease during the treatment cycle and restored normal progesterone secretion during the two posttreatment cycles. We conclude that the deleterious impact of a short-term inflammatory stress challenge on luteal function is far longer than the stress period itself. Systemic administration of astressin B accelerates the return to normal luteal function, presumably by restoring normal neuroendocrine regulation of gonadotropin secretion.

Matrix resin effects in composite delamination - Mode I fracture aspects

NASA Technical Reports Server (NTRS)

Hunston, Donald L.; Moulton, Richard J.; Johnston, Norman J.; Bascom, Willard D.

1987-01-01

A number of thermoset, toughened thermoset, and thermoplastic resin matrix systems were characterized for Mode I critical strain energy release rates, and their composites were tested for interlaminar critical strain energy release rates using the double cantilever beam method. A clear correlation is found between the two sets of data. With brittle resins, the interlaminar critical strain energy release rates are somewhat larger than the neat resin values due to a full transfer of the neat resin toughness to the composite and toughening mechanisms associated with crack growth. With tougher matrices, the higher critical strain energy release rates are only partially transferred to the composites, presumably because the fibers restrict the crack-tip deformation zones.

The use of gonadotrophin-releasing hormone antagonists in polycystic ovarian disease.

PubMed

Lubin, V; Charbonnel, B; Bouchard, P

1998-12-01

Polycystic ovarian disease (PCOD) is characterized by anovulation, eventually high luteinizing hormone (LH) levels, with increased LH pulse frequency, and hyperandrogenism. As the aetiology of the disease is still unknown, gonadotrophin-releasing hormone (GnRH) antagonists, competitive inhibitors of GnRH for its receptor, are interesting tools in order to study and treat the role of increased LH levels and pulse frequency in this disease. Their administration provokes a rapid decrease in bioactive and immunoactive LH followed by a slower decrease in follicle-stimulating hormone (FSH). In patients with PCOD, the suppression of gonadotrophin secretion eradicates the symptoms of the disease as long as the treatment lasts. Several authors have suggested that increased plasma LH levels have deleterious effects on the fertility of women with PCOD. Indeed, fewer spontaneous pregnancies with more miscarriages are observed when plasma LH levels are high. Assisted reproduction techniques such as in vitro fertilization (IVF) have provided other clues to the role of the LH secretory pattern in women with PCOD. The number of oocytes retrieved, the fertilization rate and the cleavage rate are lower in PCOD patients undergoing IVF and this is inversely correlated with FSH:LH ratio. These abnormalities are corrected when endogenous secretion of LH is suppressed. On the other hand, implantation and pregnancy rates after IVF are similar to those observed in control women. New GnRH antagonists are devoid of side effects and suppress LH secretion within a few hours without a flare-up effect. This action lasts for 10-100 hours. When GnRH antagonists are associated with i.v. pulsatile GnRH, this combination both suppresses the effect of endogenous GnRH and because of the competition for GnRH receptors restores a normal frequency of LH secretion. We have studied two women with PCOD, administering first 10 mg s.c. every 72 hours for 7 days of the GnRH antagonist Nal-Glu, then adding on top i.v. pulsatile GnRH: 10 micrograms/pulse every 90 minutes for 15 days. We thus succeeded in normalizing LH secretion pattern and observed a significant decline in testosterone levels. We failed to induce appropriate ovarian response and ovulation. In conclusion, the combination of GnRH antagonist and GnRH pulsatile treatment can re-establish normal LH secretory pattern in patients with PCOD. The failure to induce ovulation with this regimen suggests the existence of an inherent ovarian defect in women with PCOD.

Human prolactin - 24-hour pattern with increased release during sleep.

NASA Technical Reports Server (NTRS)

Sassin, J. F.; Weitzman, E. D.; Kapen, S.; Frantz, A. G.

1972-01-01

Human prolactin was measured in plasma by radioimmunoassay at 20-minute intervals for a 24-hour period in each of six normal adults, whose sleep-wake cycles were monitored polygraphically. A marked diurnal variation in plasma concentrations was demonstrated, with highest values during sleep. Periods of episodic release occurred throughout the 24 hours.

Disease-responsive drug delivery: the next generation of smart delivery devices.

PubMed

Wanakule, Prinda; Roy, Krishnendu

2012-01-01

With the advent of highly potent and cytotoxic drugs, it is increasingly critical that they be targeted and released only in cells of diseased tissues, while sparing physiologically normal neighbors. Simple ligand-based targeting of drug carriers, although promising, cannot always provide the required specificity to achieve this since often normal cells also express significant levels of the targeted receptors. Therefore, stimuli-responsive delivery systems are being explored to allow drug release from nano- and microcarriers and implantable devices, primarily in the presence of physiological or disease-specific pathophysiological signals. Designing smart biomaterials that respond to temperature or pH changes, protein and ligand binding, disease-specific degradation, e.g. enzymatic cleavage, has become an integral part of this approach. These strategies are used in combination with nano- and microparticle systems to improve delivery efficiency through several routes of administration, and with injectable or implantable systems for long term controlled release. This review focuses on recent developments in stimuli-responsive systems, their physicochemical properties, release profiles, efficacy, safety and biocompatibility, as well as future perspectives.

Renal glucose metabolism in normal physiological conditions and in diabetes.

PubMed

Alsahli, Mazen; Gerich, John E

2017-11-01

The kidney plays an important role in glucose homeostasis via gluconeogenesis, glucose utilization, and glucose reabsorption from the renal glomerular filtrate. After an overnight fast, 20-25% of glucose released into the circulation originates from the kidneys through gluconeogenesis. In this post-absorptive state, the kidneys utilize about 10% of all glucose utilized by the body. After glucose ingestion, renal gluconeogenesis increases and accounts for approximately 60% of endogenous glucose release in the postprandial period. Each day, the kidneys filter approximately 180g of glucose and virtually all of this is reabsorbed into the circulation. Hormones (most importantly insulin and catecholamines), substrates, enzymes, and glucose transporters are some of the various factors influencing the kidney's role. Patients with type 2 diabetes have an increased renal glucose uptake and release in the fasting and the post-prandial states. Additionally, glucosuria in these patients does not occur at plasma glucose levels that would normally produce glucosuria in healthy individuals. The major abnormality of renal glucose metabolism in type 1 diabetes appears to be impaired renal glucose release during hypoglycemia. Copyright © 2017 Elsevier B.V. All rights reserved.

Enhancement of Frequency Domain Indices of Heart Rate Variability by Cholinergic Stimulation with Pyridostigmine Bromide

PubMed Central

Zarei, Ali Asghar; Foroutan, Seyyed Abbas; Foroutan, Seyyed Mohsen; Erfanian Omidvar, Abbas

2011-01-01

Pyridostigmine bromide (PB) is a reversible cholinesterase inhibitor. The aim of this study was to determine the effect of orally administration of single dose sustained-released tablet of pyridostigmine bromide (PBSR) on the frequency domain indices of heart rate variability (HRV). Thirty-two healthy young men were participated in this study. They were divided into 2 groups; the pyridostigmine group (n = 22) and the placebo group (n = 10). Electrocardiogram (ECG) was recorded at 10, 30, 60, 90, 120, 150, 180, 210, 240, 300 and 420 min after PBSR administration. At each time, simultaneously, a blood sample was prepared and PB plasma concentration was measured by high-performance liquid chromatography (HPLC) method. Statistical analysis showed that in different indices of HRV, there is a significant increase in low frequency (LF) band at 300 min, but no difference in high frequency band (HF). It also showed significant decreases in normalized high frequency band (Hfnu), normalized low frequency band (Lfnu) and LF/HF ratio at 120, 240 and 300 min after PBSR administration. Maximum plasma concentration of PB was 150 min after the administration. In conclusion, administration of a single dose PBSR can enhance the frequency domains indices of HRV and improvesympathovagal balance. PMID:24250427

Coral Uptake of Inorganic Phosphorus and Nitrogen Negatively Affected by Simultaneous Changes in Temperature and pH

PubMed Central

Godinot, Claire; Houlbrèque, Fanny

2011-01-01

The effects of ocean acidification and elevated seawater temperature on coral calcification and photosynthesis have been extensively investigated over the last two decades, whereas they are still unknown on nutrient uptake, despite their importance for coral energetics. We therefore studied the separate and combined impacts of increases in temperature and pCO2 on phosphate, ammonium, and nitrate uptake rates by the scleractinian coral S. pistillata. Three experiments were performed, during 10 days i) at three pHT conditions (8.1, 7.8, and 7.5) and normal temperature (26°C), ii) at three temperature conditions (26°, 29°C, and 33°C) and normal pHT (8.1), and iii) at three pHT conditions (8.1, 7.8, and 7.5) and elevated temperature (33°C). After 10 days of incubation, corals had not bleached, as protein, chlorophyll, and zooxanthellae contents were the same in all treatments. However, photosynthetic rates significantly decreased at 33°C, and were further reduced for the pHT 7.5. The photosynthetic efficiency of PSII was only decreased by elevated temperature. Nutrient uptake rates were not affected by a change in pH alone. Conversely, elevated temperature (33°C) alone induced an increase in phosphate uptake but a severe decrease in nitrate and ammonium uptake rates, even leading to a release of nitrogen into seawater. Combination of high temperature (33°C) and low pHT (7.5) resulted in a significant decrease in phosphate and nitrate uptake rates compared to control corals (26°C, pHT = 8.1). These results indicate that both inorganic nitrogen and phosphorus metabolism may be negatively affected by the cumulative effects of ocean warming and acidification. PMID:21949839

Von Willebrand's disease with spontaneous platelet aggregation induced by an abnormal plasma von Willebrand factor.

PubMed Central

Grainick, H R; Williams, S B; McKeown, L P; Rick, M E; Maisonneuve, P; Jenneau, C; Sultan, Y

1985-01-01

We have investigated and characterized the abnormalities in four unrelated patients with von Willebrand's disease (vWd) who have (a) enhanced ristocetin-induced platelet aggregation (RIPA) at low ristocetin concentrations, (b) absence of the largest plasma von Willebrand factor (vWf) multimers, and (c) thrombocytopenia. The platelet-rich plasma of these patients aggregates spontaneously without the addition of any agonists. When isolated normal platelets are resuspended in patient plasma spontaneous aggregation occurs; however, the patients' plasmas did not induce platelet aggregation of normal washed formalinized platelets. When the patients' platelets are suspended in normal plasma, spontaneous aggregation is not observed. The spontaneous platelet aggregation (SPA) is associated with dense granule secretion as measured by ATP release and alpha granule release as measured by beta-thromboglobulin and platelet factor 4 release. The SPA is totally inhibited by 5 mM EDTA, prostaglandin I2, and dibutryl cyclic AMP, while it is only partially inhibited by 1 mM EDTA, acetylsalicylic acid, or apyrase. A monoclonal antibody directed against glycoprotein Ib (GPIb) and/or a monoclonal antibody against the glycoprotein IIb/IIIa (GPIIb/IIIa) complex totally inhibits the SPA. The vWf was isolated from the plasma of one of these patients. The purified vWf induced platelet aggregation of normal platelets resuspended in either normal or severe vWd plasma, but the vWf did not induce platelet aggregation of normal platelets resuspended in afibrinognemic plasma. Sialic acid and galactose quantification of the patient's vWf revealed approximately a 50% reduction compared with normal vWf. These studies indicate that a form of vWd exists, which is characterized by SPA that is induced by the abnormal plasma vWf. The SPA is dependent on the presence of plasma fibrinogen, and the availability of the GPIb and the GPIIb/IIIa complex. In this variant form of vWd the abnormal vWf causes enhanced RIPA, SPA, and thrombocytopenia. Images PMID:2932469

Size-amplified acoustofluidic separation of circulating tumor cells with removable microbeads

NASA Astrophysics Data System (ADS)

Liu, Huiqin; Ao, Zheng; Cai, Bo; Shu, Xi; Chen, Keke; Rao, Lang; Luo, Changliang; Wang, Fu-Bin; Liu, Wei; Bondesson, Maria; Guo, Shishang; Guo, Feng

2018-06-01

Isolation and analysis of rare circulating tumor cells (CTCs) is of great interest in cancer diagnosis, prognosis, and treatment efficacy evaluation. Acoustofluidic cell separation becomes an attractive method due to its contactless, noninvasive, simple, and versatile features. However, the indistinctive physical difference between CTCs and normal blood cells limits the purity of CTCs using current acoustic methods. Herein, we demonstrate a size-amplified acoustic separation and release of CTCs with removable microbeads. CTCs selectively bound to size-amplifiers (40 μm-diameter anti-EpCAM/gelatin-coated SiO2 microbeads) have significant physical differences (size and mechanics) compared to normal blood cells, resulting in an amplification of acoustic radiation force approximately a hundredfold over that of bare CTCs or normal blood cells. Therefore, CTCs can be efficiently sorted out with size-amplifiers in a traveling surface acoustic wave microfluidic device and released from size-amplifiers by enzymatic degradation for further purification or downstream analysis. We demonstrate a cell separation from blood samples with a total efficiency (E total) of ∼ 77%, purity (P) of ∼ 96%, and viability (V) of ∼83% after releasing cells from size-amplifiers. Our method substantially improves the emerging application of rare cell purification for translational medicine.

Radioactive release during nuclear accidents in Chernobyl and Fukushima

NASA Astrophysics Data System (ADS)

Nur Ain Sulaiman, Siti; Mohamed, Faizal; Rahim, Ahmad Nabil Ab

2018-01-01

Nuclear accidents that occurred in Chernobyl and Fukushima have initiated many research interests to understand the cause and mechanism of radioactive release within reactor compound and to the environment. Common types of radionuclide release are the fission products from the irradiated fuel rod itself. In case of nuclear accident, the focus of monitoring will be mostly on the release of noble gases, I-131 and Cs-137. As these are the only accidents have been rated within International Nuclear Events Scale (INES) Level 7, the radioactive release to the environment was one of the critical insights to be monitored. It was estimated that the release of radioactive material to the atmosphere due to Fukushima accident was approximately 10% of the Chernobyl accident. By referring to the previous reports using computational code systems to model the release rate, the release activity of I-131 and Cs-137 in Chernobyl was significantly higher compare to Fukushima. The simulation code also showed that Chernobyl had higher release rate of both radionuclides on the day of accident. Other factors affecting the radioactive release for Fukushima and Chernobyl accidents such as the current reactor technology and safety measures are also compared for discussion.

Carbonylation Induces Heterogeneity in Cardiac Ryanodine Receptor Function in Diabetes Mellitus

PubMed Central

Shao, Chun Hong; Tian, Chengju; Ouyang, Shouqiang; Moore, Caronda J.; Alomar, Fadhel; Nemet, Ina; D'Souza, Alicia; Nagai, Ryoji; Kutty, Shelby; Rozanski, George J.; Ramanadham, Sasanka; Singh, Jaipaul

2012-01-01

Heart failure and arrhythmias occur at 3 to 5 times higher rates among individuals with diabetes mellitus, compared with age-matched, healthy individuals. Studies attribute these defects in part to alterations in the function of cardiac type 2 ryanodine receptors (RyR2s), the principal Ca2+-release channels on the internal sarcoplasmic reticulum (SR). To date, mechanisms underlying RyR2 dysregulation in diabetes remain poorly defined. A rat model of type 1 diabetes, in combination with echocardiography, in vivo and ex vivo hemodynamic studies, confocal microscopy, Western blotting, mass spectrometry, site-directed mutagenesis, and [3H]ryanodine binding, lipid bilayer, and transfection assays, was used to determine whether post-translational modification by reactive carbonyl species (RCS) represented a contributing cause. After 8 weeks of diabetes, spontaneous Ca2+ release in ventricular myocytes increased ∼5-fold. Evoked Ca2+ release from the SR was nonuniform (dyssynchronous). Total RyR2 protein levels remained unchanged, but the ability to bind the Ca2+-dependent ligand [3H]ryanodine was significantly reduced. Western blotting and mass spectrometry revealed RCS adducts on select basic residues. Mutation of residues to delineate the physiochemical impact of carbonylation yielded channels with enhanced or reduced cytoplasmic Ca2+ responsiveness. The prototype RCS methylglyoxal increased and then decreased the RyR2 open probability. Methylglyoxal also increased spontaneous Ca2+ release and induced Ca2+ waves in healthy myocytes. Treatment of diabetic rats with RCS scavengers normalized spontaneous and evoked Ca2+ release from the SR, reduced carbonylation of RyR2s, and increased binding of [3H]ryanodine to RyR2s. From these data, we conclude that post-translational modification by RCS contributes to the heterogeneity in RyR2 activity that is seen in experimental diabetes. PMID:22648972

The role of spatial organization of Ca2+ release sites in the generation of arrhythmogenic diastolic Ca2+ release in myocytes from failing hearts

PubMed Central

Ho, Hsiang-Ting; Bonilla, Ingrid M.; Terentyeva, Radmila; Schober, Karsten E.; Terentyev, Dmitry; Carnes, Cynthia A.

2018-01-01

In heart failure (HF), dysregulated cardiac ryanodine receptors (RyR2) contribute to the generation of diastolic Ca2+ waves (DCWs), thereby predisposing adrenergically stressed failing hearts to life-threatening arrhythmias. However, the specific cellular, subcellular, and molecular defects that account for cardiac arrhythmia in HF remain to be elucidated. Patch-clamp techniques and confocal Ca2+ imaging were applied to study spatially defined Ca2+ handling in ventricular myocytes isolated from normal (control) and failing canine hearts. Based on their activation time upon electrical stimulation, Ca2+ release sites were categorized as coupled, located in close proximity to the sarcolemmal Ca2+ channels, and uncoupled, the Ca2+ channel-free non-junctional Ca2+ release units. In control myocytes, stimulation of β-adrenergic receptors with isoproterenol (Iso) resulted in a preferential increase in Ca2+ spark rate at uncoupled sites. This site-specific effect of Iso was eliminated by the phosphatase inhibitor okadaic acid, which caused similar facilitation of Ca2+ sparks at coupled and uncoupled sites. Iso-challenged HF myocytes exhibited increased predisposition to DCWs compared to control myocytes. In addition, the overall frequency of Ca2+ sparks was increased in HF cells due to preferential stimulation of coupled sites. Furthermore, coupled sites exhibited accelerated recovery from functional refractoriness in HF myocytes compared to control myocytes. Spatially resolved subcellular Ca2+ mapping revealed that DCWs predominantly originated from coupled sites. Inhibition of CaMK∏ suppressed DCWs and prevented preferential stimulation of coupled sites in Iso-challenged HF myocytes. These results suggest that CaMK∏-(and phosphatase)-dependent dysregulation of junctional Ca2+ release sites contributes to Ca2+-dependent arrhythmogenesis in HF. PMID:28612155

Preparation of buccal patch composed of carbopol, poloxamer and hydroxypropyl methylcellulose.

PubMed

Chun, Myung-Kwan; Kwak, Byoung-Tae; Choi, Hoo-Kyun

2003-11-01

A polymeric film composed of Carbopol, Poloxamer and hydroxypropyl methylcellulose was prepared to develop a buccal patch and the effects of composition of the film on adhesion time, swelling ratio, and dissolution of the film were studied. The effects of plasticizers or penetration enhancers on the release of triamcinolone acetonide (TAA) were also studied. The hydrogen bonding between Carbopol and Poloxamer played important role in reducing swelling ratio and dissolution rate of polymer film and increasing adhesion time. The swelling ratio of the composite film was significantly reduced and the adhesion time was increased when compared with Carbopol film. As the ratio of Poloxamer to hydroxypropyl methylcellulose increased from 0/66 to 33/33, the release rate of TAA decreased. However, no further significant decrease of release rate was observed beyond the ratio of 33/33. The release rate of TAA in the polymeric film containing polyethylene glycol 400, a plasticizer, showed the highest release rate followed by triethyl citrate, and castor oil. The release rate of TAA from the polymeric film containing permeation enhancers was slower than that from the control without enhancers. Therefore, these observations indicated that a preparation of a buccal patch is feasible with the polymeric film composed of Cabopol, Poloxamer and hydropropyl methylcellulose.

Suicide after release from prison - a population-based cohort study from Sweden

PubMed Central

Haglund, Axel; Tidemalm, Dag; Jokinen, Jussi; Långström, Niklas; Liechtenstein, Paul; Fazel, Seena; Runeson, Bo

2015-01-01

Objective Released prisoners have high suicide rates compared with the general population, but little is known about risk factors and possible causal pathways. We conducted a population-based cohort study to investigate rates and risk factors for suicide in people previously imprisoned. Methods We identified individuals released from prison in Sweden between January 1, 2005 and December 31, 2009 through linkage of national population-based registers. Released prisoners were followed from the day of release until death, emigration, new incarceration, or December 31, 2009. Survival analyses were conducted to compare incidence rates and psychiatric morbidity with non-convicted population controls matched on gender and year of birth. Results We identified 38,995 releases among 26,953 prisoners (7.6% females) during 2005-2009. Overall, 127 suicides occurred, accounting for 14% of all deaths after release (n=920). The mean suicide rate was 204 per 100,000 person years yielding an incidence rate ratio of 18.2 (95% CI 13.9-23.8) compared with general population controls. Previous substance use disorder (Hazard Ratio [HR]=2.1, 1.4-3.2), suicide attempt (HR=2.5, 1.7-3.7), and being born in Sweden vs. abroad (HR=2.1, 1.2-3.6) were independent risk factors for suicide after release. Conclusions Released prisoners are at high suicide risk and with a slightly different pattern of psychiatric risk factors for suicide compared with the general population. Results suggest appropriate allocation of resources to facilitate transition to life outside prison and increased attention to prisoners with both a previous suicide attempt and substance use disorder. PMID:25373114

Regulation of insulin secretion from islets of Langerhans rendered permeable by electric discharge

PubMed Central

Yaseen, M. Adel; Pedley, Kevin C.; Howell, Simon L.

1982-01-01

1. High-voltage electric discharge has been used to increase the permeability of B-cells of isolated islets of Langerhans to facilitate studies of the effects of normally impermeable substances on insulin secretion. 2. The application of an intense electric field increased the [14C]sucrose space of the islets from 37.8±3.1% to 86.2±5.2% of their total volume as assessed by 3H2O content. The cells remained permeable for at least 40min. 3. Ultrastructural studies showed no deleterious changes in the structure of the B-cells after discharge. 4. Insulin secretion from normal islets was unaffected by increasing the medium [Ca2+] from 10nm to 10μm. In the islets that had been rendered permeable by discharge, insulin secretion was significantly increased under these conditions, without any alteration in the release of lactate dehydrogenase, a cytoplasmic marker enzyme. 5. Studies of the dynamics of insulin release during perifusion showed that the response to increased (10μm) Ca2+ concentration was rapid and sustained over a period of at least 13min. 6. Secretion responses to Ca2+ in perifusion established that maximum release in permeabilized islets occurs at approx. 1μm-Ca2+ and half-maximum release occurs at approx. 0.6μm-Ca2+. 7. The study of the effect of agents that interfere with the microtubular microfilamentous system in B-cells using a perifusion system revealed that cytochalasin B caused a considerable increase, whereas vinblastine sulphate caused a significant inhibition, in insulin release in response to 1μm-Ca2+. 8. This technique should facilitate the study of the role of normally impermeable ions and metabolic intermediates in the regulation of insulin secretion. ImagesPLATE 1 PMID:6751326

Recurrent postural vasovagal syncope: sympathetic nervous system phenotypes.

PubMed

Vaddadi, Gautam; Guo, Ling; Esler, Murray; Socratous, Florentia; Schlaich, Markus; Chopra, Reena; Eikelis, Nina; Lambert, Gavin; Trauer, Thomas; Lambert, Elisabeth

2011-10-01

The pathophysiology of vasovagal syncope is poorly understood, and the treatment usually ineffective. Our clinical experience is that patients with vasovagal syncope fall into 2 groups, based on their supine systolic blood pressure, which is either normal (>100 mm Hg) or low (70-100 mm Hg). We investigated neural circulatory control in these 2 phenotypes. Sympathetic nervous testing was at 3 levels: electric, measuring sympathetic nerve firing (microneurography); neurochemical, quantifying norepinephrine spillover to plasma; and cellular, with Western blot analysis of sympathetic nerve proteins. Testing was done during head-up tilt (HUT), simulating the gravitational stress of standing, in 18 healthy control subjects and 36 patients with vasovagal syncope, 15 with the low blood pressure phenotype and 21 with normal blood pressure. Microneurography and norepinephrine spillover increased significantly during HUT in healthy subjects. The microneurography response during HUT was normal in normal blood pressure and accentuated in low blood pressure phenotype (P=0.05). Norepinephrine spillover response was paradoxically subnormal during HUT in both patient groups (P=0.001), who thus exhibited disjunction between nerve firing and neurotransmitter release; this lowered norepinephrine availability, impairing the neural circulatory response. Subnormal norepinephrine spillover in low blood pressure phenotype was linked to low tyrosine hydroxylase (43.7% normal, P=0.001), rate-limiting in norepinephrine synthesis, and in normal blood pressure to increased levels of the norepinephrine transporter (135% normal, P=0.019), augmenting transmitter reuptake. Patients with recurrent vasovagal syncope, when phenotyped into 2 clinical groups based on their supine blood pressure, show unique sympathetic nervous system abnormalities. It is predicted that future therapy targeting the specific mechanisms identified in the present report should translate into more effective treatment.

Preparation and release study of Triclosan in polyethylene/Triclosan anti-bacterial blend.

PubMed

Kamalipour, Jamshid; Masoomi, Mahmood; Khonakdar, Hossein Ali; Razavi, Seyed Mohammad Reza

2016-09-01

In this study, medium density polyethylene (MDPE) incorporated with Triclosan antibacterial substance has been prepared and Triclosan release rate was investigated. The crystallinity level and matrix polarity, as two significant parameters in antibacterial release control, were studied. Triclosan, a well-established widespread antibacterial agent, was incorporated into medium density polyethylene (MDPE) and Maleic anhydride grafted polyethylene (PE-g-MA) was used to change the polarity of the MDPE matrix. A masterbatch of 10wt% Triclosan incorporated with the MDPE and various PE-g-MA concentrations were prepared using an internal mixer. Then the masterbatch was diluted in the MDPE matrix to produce compounds with 0.1, 0.5, and1wt% Triclosan via twin screw extruder. The compounds were molded by compression molding method and then were cooled in three different cooling rate methods: isothermal cooling (I), quenching (Q),and moderate 5-10°C/min cooling rate (M). Cooling rate effects on crystallinity level were investigated applying sample density measurement. UV-vis absorption spectroscopy was used to probe the release of Triclosan. Antibacterial properties of the compounds against Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus were measured. The results showed that by addition of PE-g-MA, Triclosan release rate was increased. It was confirmed that the sample crystallinity was decreased by the cooling rate enhancement. The results also showed that quenched samples indicated higher release of Triclosan. Cooling rate reduction and raising the polarity increased the release of Triclosan and improved the antibacterial properties of the compounds. Copyright © 2016 Elsevier B.V. All rights reserved.

Factors affecting speech understanding in gated interference: Cochlear implant users and normal-hearing listeners

NASA Astrophysics Data System (ADS)

Nelson, Peggy B.; Jin, Su-Hyun

2004-05-01

Previous work [Nelson, Jin, Carney, and Nelson (2003), J. Acoust. Soc. Am 113, 961-968] suggested that cochlear implant users do not benefit from masking release when listening in modulated noise. The previous findings indicated that implant users experience little to no release from masking when identifying sentences in speech-shaped noise, regardless of the modulation frequency applied to the noise. The lack of masking release occurred for all implant subjects who were using three different devices and speech processing strategies. In the present study, possible causes of this reduced masking release in implant listeners were investigated. Normal-hearing listeners, implant users, and normal-hearing listeners presented with a four-band simulation of a cochlear implant were tested for their understanding of sentences in gated noise (1-32 Hz gate frequencies) when the duty cycle of the noise was varied from 25% to 75%. No systematic effect of noise duty cycle on implant and simulation listeners' performance was noted, indicating that the masking caused by gated noise is not only energetic masking. Masking release significantly increased when the number of spectral channels was increased from 4 to 12 for simulation listeners, suggesting that spectral resolution is important for masking release. Listeners were also tested for their understanding of gated sentences (sentences in quiet interrupted by periods of silence ranging from 1 to 32 Hz as a measure of auditory fusion, or the ability to integrate speech across temporal gaps. Implant and simulation listeners had significant difficulty understanding gated sentences at every gate frequency. When the number of spectral channels was increased for simulation listeners, their ability to understand gated sentences improved significantly. Findings suggest that implant listeners' difficulty understanding speech in modulated conditions is related to at least two (possibly related) factors: degraded spectral information and limitations in auditory fusion across temporal gaps.

Reaction Kernel Structure of a Slot Jet Diffusion Flame in Microgravity

NASA Technical Reports Server (NTRS)

Takahashi, F.; Katta, V. R.

2001-01-01

Diffusion flame stabilization in normal earth gravity (1 g) has long been a fundamental research subject in combustion. Local flame-flow phenomena, including heat and species transport and chemical reactions, around the flame base in the vicinity of condensed surfaces control flame stabilization and fire spreading processes. Therefore, gravity plays an important role in the subject topic because buoyancy induces flow in the flame zone, thus increasing the convective (and diffusive) oxygen transport into the flame zone and, in turn, reaction rates. Recent computations show that a peak reactivity (heat-release or oxygen-consumption rate) spot, or reaction kernel, is formed in the flame base by back-diffusion and reactions of radical species in the incoming oxygen-abundant flow at relatively low temperatures (about 1550 K). Quasi-linear correlations were found between the peak heat-release or oxygen-consumption rate and the velocity at the reaction kernel for cases including both jet and flat-plate diffusion flames in airflow. The reaction kernel provides a stationary ignition source to incoming reactants, sustains combustion, and thus stabilizes the trailing diffusion flame. In a quiescent microgravity environment, no buoyancy-induced flow exits and thus purely diffusive transport controls the reaction rates. Flame stabilization mechanisms in such purely diffusion-controlled regime remain largely unstudied. Therefore, it will be a rigorous test for the reaction kernel correlation if it can be extended toward zero velocity conditions in the purely diffusion-controlled regime. The objectives of this study are to reveal the structure of the flame-stabilizing region of a two-dimensional (2D) laminar jet diffusion flame in microgravity and develop a unified diffusion flame stabilization mechanism. This paper reports the recent progress in the computation and experiment performed in microgravity.

Crustal deformation of the Yellowstone-Snake River Plain volcano-tectonic system-Campaign and continuous GPS observations, 1987-2004

USGS Publications Warehouse

Puskas, C.M.; Smith, R.B.; Meertens, Charles M.; Chang, W. L.

2007-01-01

The Yellowstone-Snake River Plain tectonomagmatic province resulted from Late Tertiary volcanism in western North America, producing three large, caldera-forming eruptions at the Yellowstone Plateau in the last 2 Myr. To understand the kinematics and geodynamics of this volcanic system, the University of Utah conducted seven GPS campaigns at 140 sites between 1987 and 2003 and installed a network of 15 permanent stations. GPS deployments focused on the Yellowstone caldera, the Hebgen Lake and Teton faults, and the eastern Snake River Plain. The GPS data revealed periods of uplift and subsidence of the Yellowstone caldera at rates up to 15 mm/yr. From 1987 to 1995, the caldera subsided and contracted, implying volume loss. From 1995 to 2000, deformation shifted to inflation and extension northwest of the caldera. From 2000 to 2003, uplift continued to the northwest while caldera subsidence was renewed. The GPS observations also revealed extension across the Hebgen Lake fault and fault-normal contraction across the Teton fault. Deformation rates of the Yellowstone caldera and Hebgen Lake fault were converted to equivalent total moment rates, which exceeded historic seismic moment release and late Quaternary fault slip-derived moment release by an order of magnitude. The Yellowstone caldera deformation trends were superimposed on regional southwest extension of the Yellowstone Plateau at up to 4.3 ± 0.2 mm/yr, while the eastern Snake River Plain moved southwest as a slower rate at 2.1 ± 0.2 mm/yr. This southwest extension of the Yellowstone-Snake River Plain system merged into east-west extension of the Basin-Range province. Copyright 2007 by the American Geophysical Union.

Magnetotail dynamics under isobaric constraints

NASA Technical Reports Server (NTRS)

Birn, Joachim; Schindler, Karl; Janicke, Lutz; Hesse, Michael

1994-01-01

Using linear theory and nonlinear MHD simulations, we investigate the resistive and ideal MHD stability of two-dimensional plasma configurations under the isobaric constraint dP/dt = 0, which in ideal MHD is equivalent to conserving the pressure function P = P(A), where A denotes the magnetic flux. This constraint is satisfied for incompressible modes, such as Alfven waves, and for systems undergoing energy losses. The linear stability analysis leads to a Schroedinger equation, which can be investigated by standard quantum mechanics procedures. We present an application to a typical stretched magnetotail configuration. For a one-dimensional sheet equilibrium characteristic properties of tearing instability are rediscovered. However, the maximum growth rate scales with the 1/7 power of the resistivity, which implies much faster growth than for the standard tearing mode (assuming that the resistivity is small). The same basic eigen-mode is found also for weakly two-dimensional equilibria, even in the ideal MHD limit. In this case the growth rate scales with the 1/4 power of the normal magnetic field. The results of the linear stability analysis are confirmed qualitatively by nonlinear dynamic MHD simulations. These results suggest the interesting possibility that substorm onset, or the thinning in the late growth phase, is caused by the release of a thermodynamic constraint without the (immediate) necessity of releasing the ideal MHD constraint. In the nonlinear regime the resistive and ideal developments differ in that the ideal mode does not lead to neutral line formation without the further release of the ideal MHD constraint; instead a thin current sheet forms. The isobaric constraint is critically discussed. Under perhaps more realistic adiabatic conditions the ideal mode appears to be stable but could be driven by external perturbations and thus generate the thin current sheet in the late growth phase, before a nonideal instability sets in.

Insulin induces the correlation between renal blood flow and glomerular filtration rate in diabetes: implications for mechanisms causing hyperfiltration.

PubMed

Pihl, Liselotte; Persson, Patrik; Fasching, Angelica; Hansell, Peter; DiBona, Gerald F; Palm, Fredrik

2012-07-01

Glomerular filtration rate (GFR) and renal blood flow (RBF) are normally kept constant via renal autoregulation. However, early diabetes results in increased GFR and the potential mechanisms are debated. Tubuloglomerular feedback (TGF) inactivation, with concomitantly increased RBF, is proposed but challenged by the finding of glomerular hyperfiltration in diabetic adenosine A(1) receptor-deficient mice, which lack TGF. Furthermore, we consistently find elevated GFR in diabetes with only minor changes in RBF. This may relate to the use of a lower streptozotocin dose, which produces a degree of hyperglycemia, which is manageable without supplemental suboptimal insulin administration, as has been used by other investigators. Therefore, we examined the relationship between RBF and GFR in diabetic rats with (diabetes + insulin) and without suboptimal insulin administration (untreated diabetes). As insulin can affect nitric oxide (NO) release, the role of NO was also investigated. GFR, RBF, and glomerular filtration pressures were measured. Dynamic RBF autoregulation was examined by transfer function analysis between arterial pressure and RBF. Both diabetic groups had increased GFR (+60-67%) and RBF (+20-23%) compared with controls. However, only the diabetes + insulin group displayed a correlation between GFR and RBF (R(2) = 0.81, P < 0.0001). Net filtration pressure was increased in untreated diabetes compared with both other groups. The difference between untreated and insulin-treated diabetic rats disappeared after administering N(ω)-nitro-l-arginine methyl ester to inhibit NO synthase and subsequent NO release. In conclusion, mechanisms causing diabetes-induced glomerular hyperfiltration are animal model-dependent. Supplemental insulin administration results in a RBF-dependent mechanism, whereas elevated GFR in untreated diabetes is mediated primarily by a tubular event. Insulin-induced NO release partially contributes to these differences.

The release rate of environmental DNA from juvenile and adult fish.

PubMed

Maruyama, Atsushi; Nakamura, Keisuke; Yamanaka, Hiroki; Kondoh, Michio; Minamoto, Toshifumi

2014-01-01

The environmental DNA (eDNA) technique is expected to become a powerful, non-invasive tool for estimating the distribution and biomass of organisms. This technique was recently shown to be applicable to aquatic vertebrates by collecting extraorganismal DNA floating in the water or absorbed onto suspended particles. However, basic information on eDNA release rate is lacking, despite it being essential for practical applications. In this series of experiments with bluegill sunfish (Lepomis macrochirus), we examined the effect of fish developmental stage on eDNA release rate. eDNA concentration reached equilibrium 3 days after the individual fish were introduced into the separate containers, enabling calculation of the eDNA release rate (copies h-1) from individual fish on the assumption that the number of eDNA released from the fish per unit time equals total degradation in the container (copies h-1). The eDNA release rate was 3-4 times higher in the adult (body weight: 30-75 g) than in the juvenile group (0.5-2.0 g). Such positive relationship between fish size and eDNA release rate support the possibility of biomass rather than density estimation using eDNA techniques. However, the eDNA release rate per fish body weight (copies h-1 g-1) was slightly higher in the juvenile than the adult group, which is likely because of the ontogenetic reduction in metabolic activity. Therefore, quantitative eDNA data should be carefully interpreted to avoid overestimating biomass when the population is dominated by juveniles, because the age structure of the focal population is often variable and unseen in the field. eDNA degradation rates (copies l-1 h-1), calculated by curve fitting of time-dependent changes in eDNA concentrations after fish removal, were 5.1-15.9% per hour (half-life: 6.3 h). This suggests that quantitative eDNA data should be corrected using a degradation curve attained in the target field.

Can hi-jacking hypoxia inhibit extracellular vesicles in cancer?

PubMed

Lowry, Michelle C; O'Driscoll, Lorraine

2018-06-01

Increasing evidence indicates that extracellular vesicles (EVs) are key players in undesirable cell-cell communication in cancer. However, the release of EVs is not unique to cancer cells; normal cells release EVs to perform physiological roles. Thus, selective inhibition of EV release from cancer cells is desirable. Hypoxia contributes to tumour development and aggressiveness. EV quantities and thus undesirable communications are substantially increased in hypoxia. Targeting hypoxia could selectively inhibit EV release from tumour cells without disturbing physiologically relevant EVs. The unfavourable association between hypoxia and EV release is evident in multiple tumour types; therefore, targeting hypoxia could have a broad therapeutic benefit. Copyright © 2018 Elsevier Ltd. All rights reserved.

[Effects of water conditions and controlled release urea on yield and leaf senescence physiological characteristics in summer maize.

PubMed

Li, Guang Hao; Liu, Ping Ping; Zhao, Bin; Dong, Shu Ting; Liu, Peng; Zhang, Ji Wang; Tian, Cui Xia; He, Zai Ju

2017-02-01

In an soil column experiment with Zhengdan 958 (a summer maize cultivar planted widely in China), treatments of three water levels,severe water stress W 1 which the soil moisture kept (35±5)% of the field capacity, mild water stress W 2 which was (55±5)%,normal water W 3 which was (75±5)%, and four levels of controlled release urea fertilizer (N 0 , N 1 was 150 kg N·hm -2 ,N 2 was 225 kg N·hm -2 and N 3 was 300 kg N·hm -2 ) were included to study the interactive effects of water and controlled release urea on yield and leaf senescence characteristics of summer maize. The results showed that the coupling of water and controlled release urea had significant effects on increasing yield, delaying the senescence and keeping the high efficiency of the functional leaves. Under the same nitrogen condition, yield, LAI, chlorophyll content and the activities of SOD, POD, CAT and soluble protein content in summer maize ear leaf were significantly increased with more water supplying, and the content of MDA decreased significantly. Under the condition of the same moisture, these indicators were also significantly increased with the increasing nitrogen application and MDA content was reduced significantly. However, these indicators (except MDA) of W 3 N 3 , W 3 N 2 and W 2 N 3 treatments were maintained at a higher level and the MDA content was lo-wer compared with other treatments despite the fact that there were no significant difference among these three treatments, which indicated that the interactive effects of water and controlled release urea had an important role in maintaining the function of ear leaf, delaying the leaf senescence, and was beneficial to the photosynthates production and obtaining higher yield of summer maize. Integrating the yield, LAI, chlorophyll content, various protective enzymes activity, MDA and soluble protein content, controlled release urea application rate of 225 kg N·hm -2 was the best treatment as the soil moisture content was (75±5)% of field capacity. Continuous increase in the nitrogen application could not enhance the activities of protective enzymes, oppositely, it could cause the decline of protective enzymes activities and the increase of MDA content rapidly and speed up plants translation to senescence, which was not conductive to the efficient use of nitrogen. We suggested that coupling controlled release urea application rate of 300 kg N·hm -2 with soil moisture content of (55±5)% of field capacity was optimum.

Influence of factors on release of antimicrobials from antimicrobial packaging materials.

PubMed

Wu, Yu-Mei; Wang, Zhi-Wei; Hu, Chang-Ying; Nerín, Cristina

2018-05-03

Antimicrobial packaging materials (films or coatings) (APMs) have aroused great interest among the scientists or the experts specialized in material science, food science, packaging engineering, biology and chemistry. APMs have been used to package the food, such as dairy products, poultry, meat (e.g., beef), salmon muscle, pastry dough, fresh pasta, bakery products, fruits, vegetables and beverages. Some materials have been already commercialized. The ability of APMs to extend the shelf-life of the food depends on the release rate of the antimicrobials (AMs) from the materials to the food. The optimum rate is defined as target release rate (TRR). To achieve TRR, the influencing factors of the release rate should be considered. Herein we reviewed for the first time these factors and their influence on the release. These factors mainly include the AMs, food (or food simulant), packaging materials, the interactions among them, the temperature and environmental relative humidity (RH).

Effect of water-column pH on sediment-phosphorus release rates in Upper Klamath Lake, Oregon, 2001

USGS Publications Warehouse

Fisher, Lawrence H.; Wood, Tamara M.

2004-01-01

Sediment-phosphorus release rates as a function of pH were determined in laboratory experiments for sediment and water samples collected from Shoalwater Bay in Upper Klamath Lake, Oregon, in 2001. Aerial release rates for a stable sediment/water interface that is representative of the sediment surface area to water column volume ratio (1:3) observed in the lake and volumetric release rates for resuspended sediment events were determined at three different pH values (8.1, 9.2, 10.2). Ambient water column pH (8.1) was maintained by sparging study columns with atmospheric air. Elevation of the water column pH to 9.2 was achieved through the removal of dissolved carbon dioxide by sparging with carbon dioxide-reduced air, partially simulating water chemistry changes that occur during algal photosynthesis. Further elevation of the pH to 10.2 was achieved by the addition of sodium hydroxide, which doubled average alkalinities in the study columns from about 1 to 2 milliequivalents per liter. Upper Klamath Lake sediments collected from the lake bottom and then placed in contact with lake water, either at a stable sediment/water interface or by resuspension, exhibited an initial capacity to take up soluble reactive phosphorus (SRP) from the water column rather than release phosphorus to the water column. At a higher pH this initial uptake of phosphorus is slowed, but not stopped. This initial phase was followed by a reversal in which the sediments began to release SRP back into the water column. The release rate of phosphorus 30 to 40 days after suspension of sediments in the columns was 0.5 mg/L/day (micrograms per liter per day) at pH 8, and 0.9 mg/L/day at pH 10, indicating that the higher pH increased the rate of phosphorus release by a factor of about two. The highest determined rate of release was approximately 10% (percent) of the rate required to explain the annual internal loading to Upper Klamath Lake from the sediments as calculated from a lake-wide mass balance and observed in total phosphorus data collected at individual locations.

Radon Release and Its Simulated Effect on Radiation Doses.

PubMed

Orabi, Momen

2017-03-01

One of the main factors that affect the uncertainty in calculating the gamma-radiation absorbed dose rate inside a room is the variation in the degree of secular equilibrium of the considered radioactive series. A component of this factor, considered in this paper, is the release of radon (Rn) from building materials to the living space of the room. This release takes place through different steps. These steps are represented and mathematically formulated. The diffusion of radon inside the material is described by Fick's second law. Some of the factors affecting the radon release rate (e.g. covering walls, moisture, structure of the building materials, etc.) are discussed. This scheme is used to study the impact of radon release on the gamma-radiation absorbed dose rate inside a room. The investigation is carried out by exploiting the MCNP simulation software. Different building materials are considered with different radon release rates. Special care is given to Rn due to its relatively higher half-life and higher indoor concentration than the other radon isotopes. The results of the presented model show that the radon release is of a significant impact in some building materials.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Isotalo, Aarno

A method referred to as tally nuclides is presented for accurately and efficiently calculating the time-step averages and integrals of any quantities that are weighted sums of atomic densities with constant weights during the step. The method allows all such quantities to be calculated simultaneously as a part of a single depletion solution with existing depletion algorithms. Some examples of the results that can be extracted include step-average atomic densities and macroscopic reaction rates, the total number of fissions during the step, and the amount of energy released during the step. Furthermore, the method should be applicable with several depletionmore » algorithms, and the integrals or averages should be calculated with an accuracy comparable to that reached by the selected algorithm for end-of-step atomic densities. The accuracy of the method is demonstrated in depletion calculations using the Chebyshev rational approximation method. Here, we demonstrate how the ability to calculate energy release in depletion calculations can be used to determine the accuracy of the normalization in a constant-power burnup calculation during the calculation without a need for a reference solution.« less

The γ-secretase cleavage product of Polycystin-1 regulates TCF and CHOP-mediated transcriptional activation through a p300-dependent mechanism

PubMed Central

Merrick, David; Chapin, Hannah; Baggs, Julie E.; Yu, Zhiheng; Somlo, Stefan; Sun, Zhaoxia; Hogenesch, John B.; Caplan, Michael

2011-01-01

Summary Mutations in Pkd1, encoding polycystin-1 (PC1), cause Autosomal Dominant Polycystic Kidney Disease (ADPKD). We show that the carboxy-terminal tail (CTT) of PC1 is released by γ-secretase-mediated cleavage and regulates the Wnt and CHOP pathways by binding the transcription factors TCF and CHOP, disrupting their interaction with the common transcriptional co-activator p300. Loss of PC1 causes increased proliferation and apoptosis, while reintroducing PC1-CTT into cultured Pkd1 null cells reestablishes normal growth rate, suppresses apoptosis, and prevents cyst formation. Inhibition of γ-secretase activity impairs the ability of PC1 to suppress growth and apoptosis, and leads to cyst formation in cultured renal epithelial cells. Expression of the PC1-CTT is sufficient to rescue the dorsal body curvature phenotype in zebrafish embryos resulting from either γ-secretase inhibition or suppression of Pkd1 expression. Thus, γ-secretase-dependent release of the PC1-CTT creates a protein fragment whose expression is sufficient to suppress ADPKD-related phenotypes in vitro and in vivo. PMID:22178500

Calculating Time-Integral Quantities in Depletion Calculations

DOE PAGES

Isotalo, Aarno

2016-06-02

A method referred to as tally nuclides is presented for accurately and efficiently calculating the time-step averages and integrals of any quantities that are weighted sums of atomic densities with constant weights during the step. The method allows all such quantities to be calculated simultaneously as a part of a single depletion solution with existing depletion algorithms. Some examples of the results that can be extracted include step-average atomic densities and macroscopic reaction rates, the total number of fissions during the step, and the amount of energy released during the step. Furthermore, the method should be applicable with several depletionmore » algorithms, and the integrals or averages should be calculated with an accuracy comparable to that reached by the selected algorithm for end-of-step atomic densities. The accuracy of the method is demonstrated in depletion calculations using the Chebyshev rational approximation method. Here, we demonstrate how the ability to calculate energy release in depletion calculations can be used to determine the accuracy of the normalization in a constant-power burnup calculation during the calculation without a need for a reference solution.« less

Calcium release rates from tooth enamel treated with dentifrices containing whitening agents and abrasives.

PubMed

Araujo, Danilo Barral; Silva, Luciana Rodrigues; de Araujo, Roberto Paulo Correia

2010-01-01

Tooth whitening agents containing hydrogen peroxide and carbamide peroxide are used frequently in esthetic dental procedures. However, lesions on the enamel surface have been attributed to the action of these products. Using conventional procedures for separating and isolating biological structures, powdered enamel was obtained and treated with hydrogen peroxide, carbamide peroxide, and sodium bicarbonate, ingredients typically found in dentifrices. The enamel was exposed to different pH levels, and atomic emission spectrometry was used to determine calcium release rates. As the pH level increased, the rate of calcium release from enamel treated with dentifrices containing whitening agents decreased. Carbamide peroxide produced the lowest amount of decalcification, while sodium bicarbonate produced the highest release rates at all pH levels.

Fixation Release and the Bone Bandaid: A New Bone Fixation Device Paradigm

PubMed Central

Shayesteh Moghaddam, Narges; Jahadakbar, Ahmadreza; Amerinatanzi, Amirhesam; Skoracki, Roman; Miller, Michael; Dean, David; Elahinia, Mohammad

2017-01-01

The current gold standard of care for mandibular segmental defeat reconstruction is the use of Ti-6Al-4V immobilization hardware and fibular double barrel graft. This method is often successful immediately at restoring mandible function, however the highly stiff fixation hardware causes stress shielding of the grafted bone and stress concentration in the fixation device over time which can lead to fixation device failure and revision surgery. The purpose of reconstructive surgery could be to create normal stress trajectories in the mandible following engraftment. We investigate the use of a two stage mechanism which separates the immobilization/healing and regenerative phases of mandibular segmental defect treatment. The device includes the use of a very stiff, Ti-6Al-4V, releasable mechanism which assures bone healing. Therefore it could be released once the reconstructed boney tissue and any of its ligamentous attachments have completely healed. Underneath the released Ti-6Al-4V plate would be a pre-loaded nitinol (NiTi) wire-frame apparatus that facilitates the normal stress-strain trajectory through the engrafted bone after the graft is healed in place and the Ti-6Al-4V fixation device has been released. Due to the use of NiTi wires forming a netting that connects vascularized bone and possibly bone chips, bone grafts are also more likely to be incorporate rather than to resorb. We first evaluated a healthy adult mandible during normal mastication to obtain the normal stress-strain distribution. Then, we developed the finite element (FE) model of the mandibular reconstruction (in the M1-3 region) with the proposed fixation device during the healing (locked state) and post-healing (released state) periods. To recreate normal stress trajectory in the reconstructed mandible, we applied the Response Surface Methodology (RMS) to optimize the Bone Bandaid geometry (i.e., wire diameters and location). The results demonstrate that the proposed mechanism immobilizes the grafted bone in the locked state properly since the maximum resultant gap (21.54 micron) between the graft and host mandible surfaces are in the safe region (less than 300 micron). By considering the von Mises criteria for failure, FE analysis together with experimental studies (i.e., compressive and tensile testing on the inferior and superior fixation devices, respectively) confirm that the proposed fixation devices do not fail, showing safety factor of at least 10.3. Based on the Response Surface Methodology (RSM) technique, the optimal parameter values for the wires are achieved (0.65 mm and 1 mm for the superior and inferior wires, respectively) and the required level of preload on each wire are calculated (369.8 N and 229 N for the inferior and superior wires, respectively). The FE results for stress distribution on the reconstructed mandible during the released state closely match that of a healthy mandible. PMID:28952484

Chemosterilization of the sea lamprey (Petromyzon marinus)

USGS Publications Warehouse

Hanson, Lee H.; Manion, Patrick J.

1978-01-01

The chemical, P,P-bis(1-aziridinyl)-N-methylphosphinothioic amide (bisazir), was found in laboratory studies to be an effective sterilant for both sexes of adult sea lampreys (Petromyzon marinus) when given intraperitoneally at a dosage of 100 mg per kilogram of body weight. A total of 300 normal spawning-run sea lampreys and 300 injected with bisazir were released into the Big Garlic River, Marquette County, Michigan, (a small stream divided into five sections by natural barriers), to determine the effect of bisazir on the nesting and spawning behavior of the adults and on the production of larvae. The lampreys constructed and spawned in 95 nests. Sterile adults showed no abnormal nest building or spawning behavior. Sterile males competed effectively with normal males for females. Egg samples taken from nests indicated that eggs in nests where sterile males spawned with sterile or normal females did not hatch, although some embryonic development occurred. Extensive surveys with electric shockers produced no larvae in stream sections where sterile males spawned, but yielded numerous larvae in sections where normal males spawned with normal females. These findings suggest that the release of sterile males may be an effective tool in an integrated approach to control of sea lampreys in the Great Lakes.

Puromycin-sensitive aminopeptidase is the major peptidase responsible for digesting polyglutamine sequences released by proteasomes during protein degradation

PubMed Central

Bhutani, N; Venkatraman, P; Goldberg, A L

2007-01-01

Long stretches of glutamine (Q) residues are found in many cellular proteins. Expansion of these polyglutamine (polyQ) sequences is the underlying cause of several neurodegenerative diseases (e.g. Huntington's disease). Eukaryotic proteasomes have been found to digest polyQ sequences in proteins very slowly, or not at all, and to release such potentially toxic sequences for degradation by other peptidases. To identify these key peptidases, we investigated the degradation in cell extracts of model Q-rich fluorescent substrates and peptides containing 10–30 Q's. Their degradation at neutral pH was due to a single aminopeptidase, the puromycin-sensitive aminopeptidase (PSA, cytosol alanyl aminopeptidase). No other known cytosolic aminopeptidase or endopeptidase was found to digest these polyQ peptides. Although tripeptidyl peptidase II (TPPII) exhibited limited activity, studies with specific inhibitors, pure enzymes and extracts of cells treated with siRNA for TPPII or PSA showed PSA to be the rate-limiting activity against polyQ peptides up to 30 residues long. (PSA digests such Q sequences, shorter ones and typical (non-repeating) peptides at similar rates.) Thus, PSA, which is induced in neurons expressing mutant huntingtin, appears critical in preventing the accumulation of polyQ peptides in normal cells, and its activity may influence susceptibility to polyQ diseases. PMID:17318184

Ageing of a phosphate ceramic used to immobilize chloride-contaminated actinide waste

DOE Office of Scientific and Technical Information (OSTI.GOV)

Metcalfe, Brian; Donald, Ian W.; Fong, Shirley K.

2009-03-31

At AWE, we have developed a process for the immobilization of ILW waste containing a significant quantity of chloride with Ca 3(PO 4) 2 as the host material. Waste ions are incorporated into two phosphate-based phases, chlorapatite [Ca 5(PO 4) 3Cl] and spodiosite [Ca 2(PO 4)Cl]. Non-active trials performed at AWE with Sm as the actinide surrogate demonstrated the durability of these phases in aqueous solution. Trials of the process, in which actinide-doped materials were used, wer performed at PNNL where the waste form was found to be resistant to aqueous leaching. Initial leach trials conducted on 239Pu / 241Ammore » loaded ceramic at 40°C/28 days gave normalized mass losses of 1.2 x 10 -5 g.m -2 and 2.7 x 10 -3 g.m -2 for Pu and Cl respectively. In order to assess the response of the phases to radiation-induced damage, accelerated ageing trials were performed on samples in which the 239Pu was replaced with 238Pu. No changes to the crystalline structure of the waste were detected in the XRD patterns after the samples had experienced an α radiation dose of 4 x 10 18 g -1. Leach trials showed that there was an increase in the P and Ca release rates but no change in the Pu release rate.« less

Ageing of a phosphate ceramic used to immobilize chloride contaminated actinide waste

DOE Office of Scientific and Technical Information (OSTI.GOV)

Metcalfe, Brian L.; Donald, Ian W.; Fong, Shirley K.

2009-03-31

AWE has developed a process for the immobilization of ILW waste containing a significant quantity of chloride using Ca3(PO4)2 as the host material. Waste ions are incorporated into two phosphate based phases, chlorapatite, Ca5(PO4)3Cl, and spodiosite, Ca2(PO4)Cl. Non-active trials performed at AWE using samarium as the actinide surrogate demonstrated the durability of these phases in aqueous solution. Trials of the process using actinide-doped material were performed at PNNL which confirmed the immobilized wasteform resistant to aqueous leaching. Initial leach trials conducted on 239Pu /241Am loaded ceramic at 40°C/28 days gave normalized mass losses of 1.2 x 10-5 g.m-2 and 2.7more » x 10-3 g.m-2 for Pu and Cl respectively. In order to assess the response of the phases to radiation-induced damage, accelerated ageing trials were performed on samples in which the 239Pu was replaced by 238Pu. No changes to the crystalline structure of the waste were detected using XRD after the samples had experienced a radiation dose of 4 x 1018 α.g-1. Leach trials showed that there had been an increase in the P and Ca release rates but no change in the Pu release rate.« less

Smart drug release systems based on stimuli-responsive polymers.

PubMed

Qing, Guangyan; Li, Minmin; Deng, Lijing; Lv, Ziyu; Ding, Peng; Sun, Taolei

2013-07-01

Stimuli-responsive polymers could respond to external stimuli, such as temperature, pH, photo-irradiation, electric field, biomolecules in solution, etc., which further induce reversible transformations in the structures and conformations of polymers, providing an excellent platform for controllable drug release, while the accuracy of drug delivery could obtain obvious improvement in this system. In this review, recent progresses in the drug release systems based on stimuli-responsive polymers are summarized, in which drugs can be released in an intelligent mode with high accuracy and efficiency, while potential damages to normal cells and tissues can also be effectively prevented owing to the unique characteristics of materials. Moreover, we introduce some smart nanoparticles-polymers conjugates and drug release devices, which are especially suitable for the long-term sustained drug release.

[Determination of Mineral Elements in Choerospondias Axillaris and Its Extractives by ICP-AES].

PubMed

Zhai, Yu-xin; Chen, Jun; Li, Ti; Liu, Ji-yan; Wang, Xie-yi; Cheng, Chao; Liu, Cheng-mei

2015-04-01

Nine elements in Choerospondias axillaris flesh, peels, aqueous extractives and gastric digesta were determined by the inductively coupled plasma atomic emission spectrometry (ICP-AES) in the present study. The results showed that the contents of Fe, Ca, Zn, Mn, Al, Mg, Cu, K and P in the flesh were 27.37, 269.88, 1.51, 2.45, 1.95, 195.30, 2.45, 2,970.11, and 133.94 µg · g(-1), respectively. They are lower than that in the peels, about 40.31%, 11.70%, 21.68%, 4.27%, 10.58%, 15.76%, 68.72%, 42.04%, and 22.59%, respectively. For microwave assistant extraction, the release rate of Mn was highest (81.68%), while Fe was lowest (4.42%) in the flesh. The release rate of Zn was the highest (79.00%), while that of A1 was the lowest (4.94%) in the peels. Except Fe, Cu and Zn, the release rates of the other elements in flesh were higher than those in the peels. After gastric digestion, the release rates of nine elements were 3.25%-87.51% in the flesh and 7.11%-50.69% in the peels. The release rates of minerals in the flesh were found to be higher than those in the peels except Fe and Cu. Microwave assistant extraction can more efficiently release Fe, Ca, Mn, Mg and K from the flesh than the gastric digestion do. While gastric digestion had a significant effect on the peels, the release rates of elements, except Zn, were higher than those in microwave assistant extraction. Therefore, the difference of distribution and release of mineral elements between peels and flesh of Choerospondias axillaris was understood, which will provide a positive guide for further study of bioavailability of minerals for human body.

A comparison of video review and feedback device measurement of chest compressions quality during pediatric cardiopulmonary resuscitation.

PubMed

Hsieh, Ting-Chang; Wolfe, Heather; Sutton, Robert; Myers, Sage; Nadkarni, Vinay; Donoghue, Aaron

2015-08-01

To describe chest compression (CC) rate, depth, and leaning during pediatric cardiopulmonary resuscitation (CPR) as measured by two simultaneous methods, and to assess the accuracy and reliability of video review in measuring CC quality. Resuscitations in a pediatric emergency department are videorecorded for quality improvement. Patients aged 8-18 years receiving CPR under videorecording were eligible for inclusion. CPR was recorded by a pressure/accelerometer feedback device and tabulated in 30-s epochs of uninterrupted CC. Investigators reviewed videorecorded CPR and measured rate, depth, and release by observation. Raters categorized epochs as 'meeting criteria' if 80% of CCs in an epoch were done with appropriate depth (>45 mm) and/or release (<2.5 kg leaning). Comparison between device measurement and video was made by Spearman's ρ for rate and by κ statistic for depth and release. Interrater reliability for depth and release was measured by κ statistic. Five patients underwent videorecorded CPR using the feedback device. 97 30-s epochs of CCs were analyzed. CCs met criteria for rate in 74/97 (76%) of epochs; depth in 38/97 (39%); release in 82/97 (84%). Agreement between video and feedback device for rate was good (ρ = 0.77); agreement was poor for depth and release (κ 0.04-0.41). Interrater reliability for depth and release measured by video was poor (κ 0.04-0.49). Video review measured CC rate accurately; depth and release were not reliably or accurately assessed by video. Future research should focus on the optimal combination of methods for measuring CPR quality. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Mitochondrial Reactive Oxygen Species (ROS) and ROS-Induced ROS Release

PubMed Central

Zorov, Dmitry B.; Juhaszova, Magdalena; Sollott, Steven J.

2014-01-01

Byproducts of normal mitochondrial metabolism and homeostasis include the buildup of potentially damaging levels of reactive oxygen species (ROS), Ca2+, etc., which must be normalized. Evidence suggests that brief mitochondrial permeability transition pore (mPTP) openings play an important physiological role maintaining healthy mitochondria homeostasis. Adaptive and maladaptive responses to redox stress may involve mitochondrial channels such as mPTP and inner membrane anion channel (IMAC). Their activation causes intra- and intermitochondrial redox-environment changes leading to ROS release. This regenerative cycle of mitochondrial ROS formation and release was named ROS-induced ROS release (RIRR). Brief, reversible mPTP opening-associated ROS release apparently constitutes an adaptive housekeeping function by the timely release from mitochondria of accumulated potentially toxic levels of ROS (and Ca2+). At higher ROS levels, longer mPTP openings may release a ROS burst leading to destruction of mitochondria, and if propagated from mitochondrion to mitochondrion, of the cell itself. The destructive function of RIRR may serve a physiological role by removal of unwanted cells or damaged mitochondria, or cause the pathological elimination of vital and essential mitochondria and cells. The adaptive release of sufficient ROS into the vicinity of mitochondria may also activate local pools of redox-sensitive enzymes involved in protective signaling pathways that limit ischemic damage to mitochondria and cells in that area. Maladaptive mPTP- or IMAC-related RIRR may also be playing a role in aging. Because the mechanism of mitochondrial RIRR highlights the central role of mitochondria-formed ROS, we discuss all of the known ROS-producing sites (shown in vitro) and their relevance to the mitochondrial ROS production in vivo. PMID:24987008

Partial hypopituitarism and Langerhans cell histiocytosis

PubMed Central

Balaguruswamy, S; Chattington, P D

2011-01-01

A case of multisystem Langerhans cell histiocytosis with pituitary involvement nearly 20 years after initial presentation. A 48-year-old man had histiocytosis X 22 years ago initially involving the groin; subsequently his external auditory meatus, scalp, gum, mandibular bone, perineum and axilla were involved and treated. The pituitary gland was involved 4 years ago. A thyrotropin-releasing hormone test showed delayed response suggestive of hypothalamic disease. Prolactin levels were normal. A gonadotropin-releasing hormone test showed impaired testosterone and gonadotrophin response in keeping with pituitary disease. A glucagon stimulation test showed an impaired growth hormone response but a normal cortisol increase. MRI pituitary showed an empty sella. There was no evidence of diabetes insipidus. Bone mineral densitometry was normal. He has partial hypopituitarism needing thyroxine and testosterone replacement. He also developed type 2 diabetes mellitus 9 years ago. He is closely monitored for any development of diabetes insipidus and the need for growth hormone supplementation. PMID:22715201

Pseudotumour Cerebri Presentation in a Child Under the Gonadotropin-Releasing Hormone Agonist Treatment

PubMed Central

Gül, Ülkü; Kaçar Bayram, Ayşe; Kendirci, Mustafa; Hatipoğlu, Nihal; Okdemir, Deniz; Gümüş, Hakan; Kurtoğlu, Selim

2016-01-01

Gonadotropin-releasing hormone analogues are common treatment option in central precocious puberty in childhood as well as in endometriosis, infertility, and prostate cancer in adults. Pseudotumor cerebri is a rare side effect observed in adults. We present the case of a girl with precocious puberty treated with triptorelin acetate who developed pseudotumor cerebri after the 4th dose. She had headaches, and her blood pressure was detected to be above the 99 percentile. There were no causes underlying of hypertension such as cardiac, renal, or endocrine. Neurological examination was normal except bilateral papilledema. Cranial magnetic resonance imaging was normal. Cerebrospinal fluid (CSF) opening pressure was elevated. Triptorelin therapy was ceased and acetazolamide was applied; CSF pressure returned to normal. We observed pseudotumor cerebri after precocious puberty treatment, a finding for the first time ever seen in childhood. PMID:27087351

Development of a novel osmotically driven drug delivery system for weakly basic drugs.

PubMed

Guthmann, C; Lipp, R; Wagner, T; Kranz, H

2008-06-01

The drug substance SAG/ZK has a short biological half-life and because of its weakly basic nature a strong pH-dependent solubility was observed. The aim of this study was to develop a controlled release (cr) multiple unit pellet formulation for SAG/ZK with pH-independent drug release. Pellets with a drug load of 60% were prepared by extrusion/spheronization followed by cr-film coating with an extended release polyvinyl acetate/polyvinyl pyrrolidone dispersion (Kollidon SR 30 D). To overcome the problem of pH-dependent drug release the pellets were then coated with a second layer of an enteric methacrylic acid and ethyl acrylate copolymer (Kollicoat MAE 30 DP). To increase the drug release rates from the double layered cr-pellets different osmotically active ionic (sodium and potassium chloride) and nonionic (sucrose) additives were incorporated into the pellet core. Drug release studies were performed in media of different osmotic pressure to clarify the main release mechanism. Extended release coated pellets of SAG/ZK demonstrated pH-dependent drug release. Applying a second enteric coat on top of the extended release film coat failed in order to achieve pH-independent drug release. Already low enteric polymer levels on top of the extended release coated pellets decreased drug release rates at pH 1 drastically, thus resulting in a reversal of the pH-dependency (faster release at pH 6.8 than in 0.1N HCl). The addition of osmotically active ingredients (sodium and potassium chloride, and sucrose) increased the imbibing of aqueous fluids into the pellet cores thus providing a saturated drug solution inside the beads and increasing drug concentration gradients. In addition, for these pellets increased formation of pores and cracks in the polymer coating was observed. Hence drug release rates from double layered beads increased significantly. Therefore, pH-independent osmotically driven SAG/ZK release was achieved from pellets containing osmotically active ingredients and coated with an extended and enteric polymer. In contrast, with increasing osmotic pressure of the dissolution medium the in vitro drug release rates decreased significantly.

Pore Pressure Evolution in Shallow Subduction Earthquake Sequences and Effects on Aseismic Slip Transients -- Numerical Modeling With Rate and State Friction

NASA Astrophysics Data System (ADS)

Liu, Y.; Rice, J. R.

2005-12-01

In 3D modeling of long tectonic loading and earthquake sequences on a shallow subduction fault [Liu and Rice, 2005], with depth-variable rate and state friction properties, we found that aseismic transient slip episodes emerge spontaneously with only a simplified representation of effects of metamorphic fluid release. That involved assumption of a constant in time but uniformly low effective normal stress in the downdip region. As suggested by observations in several major subduction zones [Obara, 2002; Rogers and Dragert, 2003; Kodaira et al, 2004], the presence of fluids, possibly released from dehydration reactions beneath the seismogenic zone, and their pressurization within the fault zone may play an important role in causing aseismic transients and associated non-volcanic tremors. To investigate the effects of fluids in the subduction zone, particularly on the generation of aseismic transients and their various features, we develop a more complete physical description of the pore pressure evolution (specifically, pore pressure increase due to supply from dehydration reactions and shear heating, decrease due to transport and dilatancy during slip), and incorporate that into the rate and state based 3D modeling. We first incorporated two important factors, dilatancy and shear heating, following Segall and Rice [1995, 2004] and Taylor [1998]. In the 2D simulations (slip varies with depth only), a dilatancy-stabilizing effect is seen which slows down the seismic rupture front and can prevent rapid slip from extending all the way to the trench, similarly to Taylor [1998]. Shear heating increases the pore pressure, and results in faster coseismic rupture propagation and larger final slips. In the 3D simulations, dilatancy also stabilizes the along-strike rupture propagation of both seismic and aseismic slips. That is, aseismic slip transients migrate along the strike faster with a shorter Tp (the characteristic time for pore pressure in the fault core to re-equilibrate with that of its surroundings). This is consistent with our previous simulations, which show that the aseismic transients migrate along the strike at a higher speed under a lower, constant in time, effective normal stress. As a combination of the two factors, we show the pore pressure evolution with drops (due to dilatancy during slip) and then rises (due to shear heating) on the fault over multiple time scales. We next plan to formulate, and merge with the slip-rupture analysis, fuller fluid release models based on phase equilibria and models of transport in which the average fault-parallel permeability is a decreasing function of the effective normal stress. The thrust fault zone, at seismogenic depths and slightly downdip, is represented in a conceptually similar manner to the well-studied major continental faults, assuming the fault core materials have a lower permeability than the neighboring damaged zone. Heat diffusion in the fault core and damaged zone will also be considered in the modeling. The simulation results may help to improve our understanding of the processes of the aseismic transients observed within a transform plate boundary along the SAF near Cholame, California [Nadeau and Dolenc, 2005].

Orthotopic Transplantation of Cryopreserved Mouse Ovaries and Gonadotrophin Releasing Hormone Analogues in the Restoration of Function following Chemotherapy-Induced Ovarian Damage

PubMed Central

Li, Qing; Szatmary, Peter; Liu, Yanyang; Ding, Zhenyu; Zhou, Jin; Sun, Yi; Luo, Feng

2015-01-01

Therapy advances are constantly improving survival rates of cancer patients, however the toxic effects of chemotherapy drugs can seriously affect patients’ quality of life. In women, fertility and premature ovarian endocrine dysfunction are of particular concern. It is urgently we find methods to preserve or reconstruct ovarian function for these women. This study compares GnRHa treatment with ovarian tissue cryopreservation and orthotopic transplantation in a chemotherapy-induced ovarian damage murine model. 56 inbred Lewis rats were divided into 4 treatment groups: Saline control (group I); cyclophosphamide only (group II); cyclophosphamide plus GnRHa (group III); cyclophosphamide and grafting of thawed cryopreserved ovaries (group IV). Body weight, estrous cycle recovery time, ovarian weight, morphology and follicle count, as well as breeding and fertility were compared among groups. Only group IV was able to restore to normal body weight by the end of the observation period and resumed normal estrous cycles in a shorter time compared to other treatment groups. There was a decrease in primordial follicles in all treatment groups, but group III had the greatest reduction. Although, there was no difference in pregnancy, only one animal littered normal pups in group II, none littered in group III and four littered in group IV. Thus, cryopreservation and orthotopic transplantation of ovarian tissue can restore the fertility of rats subjected to chemotherapy in a manner that is superior to GnRHa treatment. We also observed increased rates of hepatic, splenic and pulmonary haemorrhage in group III, suggesting there may be synergistic toxicity of GnRHa and cyclophosphamide. PMID:25811681

Freeze-all cycle for all normal responders?

PubMed

Roque, Matheus; Valle, Marcello; Guimarães, Fernando; Sampaio, Marcos; Geber, Selmo

2017-02-01

The purpose of this study is to evaluate the freeze-all strategy in subgroups of normal responders, to assess whether this strategy is beneficial regardless of ovarian response, and to evaluate the possibility of implementing an individualized embryo transfer (iET) based on ovarian response. This was an observational, cohort study performed in a private IVF center. A total of 938 IVF cycles were included in this study. The patients were submitted to controlled ovarian stimulation (COS) with a gonadotropin-releasing hormone (GnRH) antagonist protocol and a cleavage-stage day 3 embryo transfer. We performed a comparison of outcomes between the fresh embryo transfer (n = 523) and the freeze-all cycles (n = 415). The analysis was performed in two subgroups of patients based on the number of retrieved oocytes: Group 1 (4-9 oocytes) and Group 2 (10-15 oocytes). In Group 1 (4-9 retrieved oocytes), the implantation rates (IR) were 17.9 and 20.5% (P = 0.259) in the fresh and freeze-all group, respectively; the ongoing pregnancy rates (OPR) were 31 and 33% (P = 0.577) in the fresh and freeze-all group, respectively. In Group 2 (10-15 oocytes), the IR were 22.1 and 30.1% (P = 0.028) and the OPR were 34 and 47% (P = 0.021) in the fresh and freeze-all groups, respectively. Although the freeze-all policy may be related to better in vitro fertilization (IVF) outcomes in normal responders, these potential advantages decrease with worsening ovarian response. Patients with poorer ovarian response do not benefit from the freeze-all strategy.

Distribution Development for STORM Ingestion Input Parameters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fulton, John

The Sandia-developed Transport of Radioactive Materials (STORM) code suite is used as part of the Radioisotope Power System Launch Safety (RPSLS) program to perform statistical modeling of the consequences due to release of radioactive material given a launch accident. As part of this modeling, STORM samples input parameters from probability distributions with some parameters treated as constants. This report described the work done to convert four of these constant inputs (Consumption Rate, Average Crop Yield, Cropland to Landuse Database Ratio, and Crop Uptake Factor) to sampled values. Consumption rate changed from a constant value of 557.68 kg / yr tomore » a normal distribution with a mean of 102.96 kg / yr and a standard deviation of 2.65 kg / yr. Meanwhile, Average Crop Yield changed from a constant value of 3.783 kg edible / m 2 to a normal distribution with a mean of 3.23 kg edible / m 2 and a standard deviation of 0.442 kg edible / m 2 . The Cropland to Landuse Database ratio changed from a constant value of 0.0996 (9.96%) to a normal distribution with a mean value of 0.0312 (3.12%) and a standard deviation of 0.00292 (0.29%). Finally the crop uptake factor changed from a constant value of 6.37e -4 (Bq crop /kg)/(Bq soil /kg) to a lognormal distribution with a geometric mean value of 3.38e -4 (Bq crop /kg)/(Bq soil /kg) and a standard deviation value of 3.33 (Bq crop /kg)/(Bq soil /kg)« less

Computational Studies of Drug Release, Transport and Absorption in the Human Intestines

NASA Astrophysics Data System (ADS)

Behafarid, Farhad; Brasseur, J. G.; Vijayakumar, G.; Jayaraman, B.; Wang, Y.

2016-11-01

Following disintegration of a drug tablet, a cloud of particles 10-200 μm in diameter enters the small intestine where drug molecules are absorbed into the blood. Drug release rate depends on particle size, solubility and hydrodynamic enhancements driven by gut motility. To quantify the interrelationships among dissolution, transport and wall permeability, we apply lattice Boltzmann method to simulate the drug concentration field in the 3D gut released from polydisperse distributions of drug particles in the "fasting" vs. "fed" motility states. Generalized boundary conditions allow for both solubility and gut wall permeability to be systematically varied. We apply a local 'quasi-steady state' approximation for drug dissolution using a mathematical model generalized for hydrodynamic enhancements and heterogeneity in drug release rate. We observe fundamental differences resulting from the interplay among release, transport and absorption in relationship to particle size distribution, luminal volume, motility, solubility and permeability. For example, whereas smaller volume encourages higher bulk concentrations and reduced release rate, it also encourages higher absorption rate, making it difficult to generalize predictions. Supported by FDA.

Development of near zero-order release dosage forms using three-dimensional printing (3-DP) technology.

PubMed

Wang, Chen-Chao; Tejwani Motwani, Monica R; Roach, Willie J; Kay, Jennifer L; Yoo, Jaedeok; Surprenant, Henry L; Monkhouse, Donald C; Pryor, Timothy J

2006-03-01

Three near zero-order controlled-release pseudoephedrine hydrochloride (PEH) formulations demonstrating proportional release rates were developed using 3-Dimensional Printing (3-DP) technology. Mixtures of Kollidon SR and hydroxypropylmethyl cellulose (HPMC) were used as drug carriers. The release rates were adjusted by varying the Kollidon SR-HPMC ratio while keeping fabrication parameters constant. The dosage forms were composed of an immediate release core and a release rate regulating shell, fabricated with an aqueous PEH and an ethanolic triethyl citrate (TEC) binder, respectively. The dosage form design called for the drug to be released via diffusional pathways formed by HPMC in the shell matrix. The release rate was shown to increase correspondingly with the fraction of HPMC contained in the polymer blend. The designed formulations resulted in dosage forms that were insensitive to changes in pH of the dissolution medium, paddle stirring rate, and the presence/absence of a sinker. The near zero-order release properties were unchanged regardless of the dissolution test being performed on either single cubes or on a group of eight cubes encased within a gelatin capsule shell. The chemical and dissolution properties of the three formulations remained unchanged following 1 month's exposure to 25 degrees C/60% RH or 40 degrees C/75% RH environment under open container condition. The in vivo performance of the three formulations was evaluated using a single-dose, randomized, open-label, four-way crossover clinical study composed of 10 fasted healthy volunteers. The pharmacokinetic parameters were analyzed using a noncompartmental model. Qualitative rank order linear correlations between in vivo absorption profiles and in vitro dissolution parameters (with slope and intercept close to unity and origin, respectively) were obtained for all three formulations, indicating good support for a Level A in vivo/in vitro correlation.

Use of proteins to minimize the physical aging of EUDRAGIT sustained release films.

PubMed

Kucera, Shawn A; McGinity, James W; Zheng, Weijia; Shah, Navnit H; Malick, A Waseem; Infeld, Martin H

2007-07-01

The objective of this study was to investigate the influence of two proteins, albumin and type B gelatin, on the physical aging of EUDRAGIT RS 30 D and RL 30 D coated theophylline pellets. The physicomechanical properties of sprayed films, thermal properties of cast films, influence of proteins on the zeta potential and particle size of the dispersion, and the release of proteins from cast films under simulated dissolution conditions were investigated. The release rate of theophylline decreased significantly over time from pellets coated with an acrylic dispersion containing 10% albumin when there was no acidification of the acrylic dispersion; however, when pellets were coated with an acidified EUDRAGIT/albumin dispersion, the theophylline release rate was stable for dosage forms stored in the absence of humidity. The drug release rate was faster for pellets coated with acrylic dispersions containing 10% gelatin compared to the albumin-containing formulations. When sprayed films were stored at 40 degrees C/75% RH, the water vapor permeability decreased significantly for both EUDRAGIT films and those containing EUDRAGIT and albumin; however, there was no significant change in this parameter when 10% gelatin was present. Albumin was released from the acrylic films when the pH of the dissolution media was below the isoelectric point of the protein while no quantitative release of gelatin was observed in pH 1.2 or 7.4 media. The effect of gelatin to prevent the decrease in drug release rate was due to stabilization in water vapor permeability of the film. Acidification of the polymeric dispersion resulted in electrostatic repulsive forces between albumin and the acrylic polymer, which stabilized the drug release rate when the dosage forms were stored in aluminum induction sealed containers at both 40 degrees C/75% RH and 25 degrees C/60% RH.

Timing of translocation influences birth rate and population dynamics in a forest carnivore

USGS Publications Warehouse

Facka, Aaron N; Lewis, Jeffrey C.; Happe, Patricia; Jenkins, Kurt J.; Callas, Richard; Powell, Roger A.

2016-01-01

Timing can be critical for many life history events of organisms. Consequently, the timing of management activities may affect individuals and populations in numerous and unforeseen ways. Translocations of organisms are used to restore or expand populations but the timing of translocations is largely unexplored as a factor influencing population success. We hypothesized that the process of translocation negatively influences reproductive rates of individuals that are moved just before their birthing season and, therefore, the timing of releases could influence translocation success. Prior to reintroducing fishers (Pekania pennanti) into northern California and onto the Olympic Peninsula of Washington, we predicted that female fishers released in November and December (early) would have a higher probability of giving birth to kits the following March or April than females released in January, February, and March (late), just prior to or during the period of blastocyst implantation and gestation. Over four winters (2008–2011), we translocated 56 adult female fishers that could have given birth in the spring immediately after release. Denning rates, an index of birth rate, for females released early were 92% in California and 38% in Washington. In contrast, denning rates for females released late were 40% and 11%, in California and Washington, a net reduction in denning rate of 66% across both sites. To understand how releasing females nearer to parturition could influence population establishment and persistence, we used stochastic population simulations using three-stage Lefkovitch matrices. These simulations showed that translocating female fishers early had long-term positive influences on the mean population size and on quasi-extinction thresholds compared to populations where females were released late. The results from both empirical data and simulations show that the timing of translocation, with respect to life history events, should be considered during planning of translocations and implemented before the capture, movement, and release of organisms for translocation.

Effect of Stitching on Debonding in Composite Structural Elements

NASA Technical Reports Server (NTRS)

Raju, I. S.; Glaessgen, E. H.

2001-01-01

Stitched multiaxial warp knit materials have been suggested as viable alternatives to laminated prepreg materials for large aircraft structures such as wing skins. Analyses have been developed to quantify the effectiveness of stitching for reducing strain energy release rates in skin-stiffener debond, lap joint and sandwich debond configurations. Strain energy release rates were computed using the virtual crack closure technique. In all configurations, the stitches were shown to significantly reduce the strain energy release rate.

Chloride retention and release in a boreal forest soil: effects of soil water residence time and nitrogen and chloride loads.

PubMed

Bastviken, David; Sandén, Per; Svensson, Teresia; Ståhlberg, A Carina; Magounakis, Malin; Oberg, Gunilla

2006-05-01

The common assumption that chloride (Cl-) is conservative in soils and can be used as a groundwater tracer is currently being questioned, and an increasing number of studies indicate that Cl- can be retained in soils. We performed lysimeter experiments with soil from a coniferous forest in southeast Sweden to determine whether pore water residence time and nitrogen and Cl- loads affected Cl- retention. Over the first 42 days there was a net retention of Cl- with retention rates averaging 3.1 mg CI- m(-2) d(-1) (68% of the added Cl- retained over 42 days). Thereafter, a net release of Cl- at similar rates was observed for the remaining experimental period (85 d). Longer soil water residence time and higher Cl- load gave higher initial retention and subsequent release rates than shorter residence time and lower Cl- load did. Nitrogen load did not affect Cl transformation rates. This study indicates that simultaneous retention and release of Cl- can occur in soils, and that rates may be considerable relative to the load. The retention of Cl- observed was probably due to chlorination of soil organic matter or ion exchange. The cause of the shift between net retention and net release is unclear, but we hypothesize that the presence of O2 or the presence of microbially available organic matter regulates Cl- retention and release rates.

Influence of Finite Element Software on Energy Release Rates Computed Using the Virtual Crack Closure Technique

NASA Technical Reports Server (NTRS)

Krueger, Ronald; Goetze, Dirk; Ransom, Jonathon (Technical Monitor)

2006-01-01

Strain energy release rates were computed along straight delamination fronts of Double Cantilever Beam, End-Notched Flexure and Single Leg Bending specimens using the Virtual Crack Closure Technique (VCCT). Th e results were based on finite element analyses using ABAQUS# and ANSYS# and were calculated from the finite element results using the same post-processing routine to assure a consistent procedure. Mixed-mode strain energy release rates obtained from post-processing finite elem ent results were in good agreement for all element types used and all specimens modeled. Compared to previous studies, the models made of s olid twenty-node hexahedral elements and solid eight-node incompatible mode elements yielded excellent results. For both codes, models made of standard brick elements and elements with reduced integration did not correctly capture the distribution of the energy release rate acr oss the width of the specimens for the models chosen. The results suggested that element types with similar formulation yield matching results independent of the finite element software used. For comparison, m ixed-mode strain energy release rates were also calculated within ABAQUS#/Standard using the VCCT for ABAQUS# add on. For all specimens mod eled, mixed-mode strain energy release rates obtained from ABAQUS# finite element results using post-processing were almost identical to re sults calculated using the VCCT for ABAQUS# add on.

Reproduction and Development of the Released Przewalski’s Horses (Equus przewalskii) in Xinjiang, China

PubMed Central

CHEN, Jinliang; WENG, Qiang; CHAO, Jie; HU, Defu; TAYA, Kazuyoshi

2008-01-01

In China, the first Przewalski’s horse (Equus przewalskii) group was released in Kalamaili Ungulate Protected Area in Xinjiang, in August 2001. The objective of this study was to investigate reproduction and development of released Przewalski’s horses in Xinjiang, China from 2002 to 2006. Twenty-four descendants were naturally born, average reproduction rate was 38.7%, and average survival rate of foals was 69.1% in this interim. Frequent alternation of the leading stallion and infertility in female horses due to environmental factors were main causes for the low reproduction rate. The infant mortality rate of released Przewalski’s horses was 25.0%, and 83.3% of death in infants was due to the leading stallion infanticide. The released Przewalski’s horses exhibited seasonal breeding, 70.8% of infants were born in May and June. The fertility rates were 8.3% in April and 37.5% in May, which were lower compared to those of the captive Przewalski’s horse groups (18.3% and 44.3%, respectively). Furthermore, the fertility rate in June was 33.3% and higher than the captive groups (18.3%). These findings showed that the breeding peak of the released Przewalski’s horse groups was later than the captive groups, and suggested that the altered survival environment and food supplies were the main reasons contributing to the delayed breeding peak. PMID:24833949

Analysis of the effects on body temperature of intracerebroventricular injection in anaesthetized dogs of gamma-aminobutyric acid

PubMed Central

Dhumal, V.R.; Gulati, O.D.; Raghunath, P.R.; Sivaramakrishna, N.

1974-01-01

1 The cerebral ventricles of dogs under intravenous pentobarbitone sodium anaesthesia, were perfused with artificial cerebro-spinal fluid (CSF) at a rate of 0.4-0.5 ml/min from the ventricular to the aqueductal cannulae. The effluent was collected from the aqueductal cannula in 20 min samples. The animals' temperatures were recorded from the rectum. 2 γ-Aminobutyric acid (GABA) 0.1-5 mg when injected into the ventricles produced variable temperature effects. Doses of 0.1 and 0.5 mg always produced hyperthermia and 1 and 5 mg doses sometimes produced hyperthermia and sometimes hypothermia. 3 Intraventricular perfusion with 2-bromolysergic acid diethylamide (BOL) and hyoscine did not block hyperthermia. Tests on the rat isolated stomach strip or the guinea-pig isolated superfused ileum for the possible release, respectively, of 5-hydroxytryptamine or acetylcholine by GABA were negative. 4 When tested for the presence of prostaglandin E(PGE)-like substances on the isolated rat stomach strip, both the control effluent and the GABA effluent showed activity, the latter being much more potent. There was a temporal correlation between this effect and hyperthermia. Intraventricularly administered sodium salicylate converted the GABA-induced hyperthermia to hypothermia and blocked the release of PGE-like substances. 5 Hypothermia induced by GABA alone or in the presence of sodium salicylate was associated with the release of noradrenaline into the effluent. 6 Intraventricular administration of GABA in reserpinized dogs produced hyperthermia and not hypothermia. Similar results were obtained with phentolamine perfusion in normal dogs. 7 Perfusion with calcium-free solution blocked both the noradrenaline-releasing and hypothermic actions of GABA. 8 It is concluded that hyperthermia associated with intraventricular injections of GABA is due to the release of PGE-like substance and hypothermia is due to the release of noradrenaline. PMID:4155652

Multifunctional halloysite nanotubes for targeted delivery and controlled release of doxorubicin in-vitro and in-vivo studies

NASA Astrophysics Data System (ADS)

Hu, Yuwei; Chen, Jian; Li, Xiufang; Sun, Yanhua; Huang, Shen; Li, Yuqing; Liu, Hui; Xu, Jiangfeng; Zhong, Shian

2017-09-01

The current state of cancer therapy encourages researchers to develop novel efficient nanocarriers. Halloysite nanotubes (HNTs) are good nanocarrier candidates due to their unique nanoscale (40-80 nm in diamter and 200-500 nm in length) and hollow lumen, as well as good biocompatibility and low cost. In our study, we prepared a type of folate-mediated targeting and redox-triggered anticancer drug delivery system, so that Doxorubicin (DOX) can be specifically transported to tumor sites due to the over-expressed folate-receptors on the surface of cancer cells. Furthermore, it can then be released by the reductive agent glutathione (GSH) in cancer cells where the content of GSH is nearly 103-fold higher than in the extracellular matrix. A series of methods have demonstrated that per-thiol-β-cyclodextrin (β-CD-(SH)7) was successfully combined with HNTs via a redox-responsive disulfide bond, and folic acid-polyethylene glycol-adamantane (FA-PEG-Ad) was immobilized on the HNTs through the strong complexation between β-CD/Ad. In vitro studies indicated that the release rate of DOX raised sharply in dithiothreitol (DTT) reducing environment and the amount of released DOX reached 70% in 10 mM DTT within the first 10 h, while only 40% of DOX was released in phosphate buffer solution (PBS) even after 79 h. Furthermore, the targeted HNTs could be specifically endocytosed by over-expressed folate-receptor cancer cells and significantly accelerate the apoptosis of cancer cells compared to non-targeted HNTs. In vivo studies further verified that the targeted HNTs had the best therapeutic efficacy and no obvious side effects for tumor-bearing nude mice, while free DOX showed damaging effects on normal tissues. In summary, this novel nanocarrier system shows excellent potential for targeted delivery and controlled release of anticancer drugs and provides a potential platform for tumor therapy.

ICP-MS analysis of fission product diffusion in graphite for High-Temperature Gas-Cooled Reactors

NASA Astrophysics Data System (ADS)

Carter, Lukas M.

Release of radioactive fission products from nuclear fuel during normal reactor operation or in accident scenarios is a fundamental safety concern. Of paramount importance are the understanding and elucidation of mechanisms of chemical interaction, nuclear interaction, and transport phenomena involving fission products. Worldwide efforts to reduce fossil fuel dependence coupled with an increasing overall energy demand have generated renewed enthusiasm toward nuclear power technologies, and as such, these mechanisms continue to be the subjects of vigorous research. High-Temperature Gas-Cooled Reactors (HTGRs or VHTRs) remain one of the most promising candidates for the next generation of nuclear power reactors. An extant knowledge gap specific to HTGR technology derives from an incomplete understanding of fission product transport in major core materials under HTGR operational conditions. Our specific interest in the current work is diffusion in reactor graphite. Development of methods for analysis of diffusion of multiple fission products is key to providing accurate models for fission product release from HTGR core components and the reactor as a whole. In the present work, a specialized diffusion cell has been developed and constructed to facilitate real-time diffusion measurements via ICP-MS. The cell utilizes a helium gas-jet system which transports diffusing fission products to the mass spectrometer using carbon nanoparticles. The setup was designed to replicate conditions present in a functioning HTGR, and can be configured for real-time release or permeation measurements of single or multiple fission products from graphite or other core materials. In the present work, we have analyzed release rates of cesium in graphite grades IG-110, NBG-18, and a commercial grade of graphite, as well as release of iodine in IG-110. Additionally we have investigated infusion of graphite samples with Cs, I, Sr, Ag, and other surrogate fission products for use in release or profile measurements of diffusion coefficients.

NEW IMPROVEMENTS TO MFIRE TO ENHANCE FIRE MODELING CAPABILITIES.

PubMed

Zhou, L; Smith, A C; Yuan, L

2016-06-01

NIOSH's mine fire simulation program, MFIRE, is widely accepted as a standard for assessing and predicting the impact of a fire on the mine ventilation system and the spread of fire contaminants in coal and metal/nonmetal mines, which has been used by U.S. and international companies to simulate fires for planning and response purposes. MFIRE is a dynamic, transient-state, mine ventilation network simulation program that performs normal planning calculations. It can also be used to analyze ventilation networks under thermal and mechanical influence such as changes in ventilation parameters, external influences such as changes in temperature, and internal influences such as a fire. The program output can be used to analyze the effects of these influences on the ventilation system. Since its original development by Michigan Technological University for the Bureau of Mines in the 1970s, several updates have been released over the years. In 2012, NIOSH completed a major redesign and restructuring of the program with the release of MFIRE 3.0. MFIRE's outdated FORTRAN programming language was replaced with an object-oriented C++ language and packaged into a dynamic link library (DLL). However, the MFIRE 3.0 release made no attempt to change or improve the fire modeling algorithms inherited from its previous version, MFIRE 2.20. This paper reports on improvements that have been made to the fire modeling capabilities of MFIRE 3.0 since its release. These improvements include the addition of fire source models of the t-squared fire and heat release rate curve data file, the addition of a moving fire source for conveyor belt fire simulations, improvement of the fire location algorithm, and the identification and prediction of smoke rollback phenomena. All the improvements discussed in this paper will be termed as MFIRE 3.1 and released by NIOSH in the near future.

Oxygen-Releasing Antioxidant Cryogel Scaffolds with Sustained Oxygen Delivery for Tissue Engineering Applications.

PubMed

Shiekh, Parvaiz A; Singh, Anamika; Kumar, Ashok

2018-06-06

With the advancement in biomaterial sciences, tissue-engineered scaffolds are developing as a promising strategy for the regeneration of damaged tissues. However, only a few of these scaffolds have been translated into clinical applications. One of the primary drawbacks of the existing scaffolds is the lack of adequate oxygen supply within the scaffolds. Oxygen-producing biomaterials have been developed as an alternate strategy but are faced with two major concerns. One is the control of the rate of oxygen generation, and the other is the production of reactive oxygen species (ROS). To address these concerns, here, we report the development of an oxygen-releasing antioxidant polymeric cryogel scaffold (PUAO-CPO) for sustained oxygen delivery. PUAO-CPO scaffold was fabricated using the cryogelation technique by the incorporation of calcium peroxide (CPO) in the antioxidant polyurethane (PUAO) scaffolds. The PUAO-CPO cryogels attenuated the ROS and showed a sustained release of oxygen over a period of 10 days. An in vitro analysis of the PUAO-CPO cryogels showed their ability to sustain H9C2 cardiomyoblast cells under hypoxic conditions, with cell viability being significantly better than the normal polyurethane (PU) scaffolds. Furthermore, in vivo studies using an ischemic flap model showed the ability of the oxygen-releasing cryogel scaffolds to prevent tissue necrosis upto 9 days. Histological examination indicated the maintenance of tissue architecture and collagen content, whereas immunostaining for proliferating cell nuclear antigen confirmed the viability of the ischemic tissue with oxygen delivery. Our study demonstrated an advanced approach for the development of oxygen-releasing biomaterials with sustained oxygen delivery as well as attenuated production of residual ROS and free radicals because of ischemia or oxygen generation. Hence, the oxygen-releasing PUAO-CPO cryogel scaffolds may be used with cell-based therapeutic approaches for the regeneration of damaged tissue, particularly with ischemic conditions such as myocardial infarction and chronic wound healing.

Exploring virus release as a bottleneck for the spread of influenza A virus infection in vitro and the implications for antiviral therapy with neuraminidase inhibitors

PubMed Central

Kowal, Szymon; Cardenas, Daniel A.; Beauchemin, Catherine A. A.

2017-01-01

Mathematical models (MMs) have been used to study the kinetics of influenza A virus infections under antiviral therapy, and to characterize the efficacy of antivirals such as neuraminidase inhibitors (NAIs). NAIs prevent viral neuraminidase from cleaving sialic acid receptors that bind virus progeny to the surface of infected cells, thereby inhibiting their release, suppressing infection spread. When used to study treatment with NAIs, MMs represent viral release implicitly as part of viral replication. Consequently, NAIs in such MMs do not act specifically and exclusively on virus release. We compared a MM with an explicit representation of viral release (i.e., distinct from virus production) to a simple MM without explicit release, and investigated whether parameter estimation and the estimation of NAI efficacy were affected by the use of a simple MM. Since the release rate of influenza A virus is not well-known, a broad range of release rates were considered. If the virus release rate is greater than ∼0.1 h−1, the simple MM provides accurate estimates of infection parameters, but underestimates NAI efficacy, which could lead to underdosing and the emergence of NAI resistance. In contrast, when release is slower than ∼0.1 h−1, the simple MM accurately estimates NAI efficacy, but it can significantly overestimate the infectious lifespan (i.e., the time a cell remains infectious and producing free virus), and it will significantly underestimate the total virus yield and thus the likelihood of resistance emergence. We discuss the properties of, and a possible lower bound for, the influenza A virus release rate. PMID:28837615

Tobacco use in popular movies during the past decade.

PubMed

Mekemson, C; Glik, D; Titus, K; Myerson, A; Shaivitz, A; Ang, A; Mitchell, S

2004-12-01

The top 50 commercially successful films released per year from 1991 to 2000 were content coded to assess trends in tobacco use over time and attributes of films predictive of higher smoking rates. This observational study used media content analysis methods to generate data about tobacco use depictions in films studied (n = 497). Films are the basic unit of analysis. Once films were coded and preliminary analysis completed, outcome data were transformed to approximate multivariate normality before being analysed with general linear models and longitudinal mixed method regression methods. Tobacco use per minute of film was the main outcome measure used. Predictor variables include attributes of films and actors. Tobacco use was defined as any cigarette, cigar, and chewing tobacco use as well as the display of smoke and cigarette paraphernalia such as ashtrays, brand names, or logos within frames of films reviewed. Smoking rates in the top films fluctuated yearly over the decade with an overall modest downward trend (p < 0.005), with the exception of R rated films where rates went up. The decrease in smoking rates found in films in the past decade is modest given extensive efforts to educate the entertainment industry on this issue over the past decade. Monitoring, education, advocacy, and policy change to bring tobacco depiction rates down further should continue.

[In vitro drug release behavior of carrier made of porous glass ceramics].

PubMed

Wang, De-ping; Huang, Wen-hai; Zhou, Nai

2002-09-01

To conduct the in vitro test on drug release of rifampin encapsulated in a carrier made of porous phosphate glass ceramics and to analyze main factors which affect the drug release rate. A certain quantitative of rifampin was sealed in a hollow cylindrical capsule which consisted of chopped calcium phosphate crystal fiber obtained from glass crystallization. The rifampin concentration was measured in the simulated physiological solution in which the capsule soaked. Rifampin could be released in a constant rate from the porous glass ceramic carrier in a long time. The release rate was dependent on the size of crystal fiber and the wall thickness of the capsule. This kind of calcium phosphate glass ceramics can be a candidate of the carrier materials used as long term drug therapy after osteotomy surgery.

Changes of body temperature and thermoregulatory responses of freely moving rats during GABAergic pharmacological stimulation to the preoptic area and anterior hypothalamus in several ambient temperatures.

PubMed

Ishiwata, Takayuki; Saito, Takehito; Hasegawa, Hiroshi; Yazawa, Toru; Kotani, Yasunori; Otokawa, Minoru; Aihara, Yasutsugu

2005-06-28

Action of gamma-aminobutyric acid (GABA) in the preoptic area and anterior hypothalamus (PO/AH) has been implicated to regulate body temperature (T(b)). However, its precise role in thermoregulation remains unclear. Moreover, little is known about its release pattern in the PO/AH during active thermoregulation. Using microdialysis and telemetry techniques, we measured several parameters related to thermoregulation of freely moving rats during pharmacological stimulation of GABA in normal (23 degrees C), cold (5 degrees C), and hot (35 degrees C) ambient temperatures. We also measured extracellular GABA levels in the PO/AH during cold (5 degrees C) and heat (35 degrees C) exposure combined with microdialysis and high performance liquid chromatography (HPLC). Perfusion of GABA(A) agonist muscimol into the PO/AH increased T(b), which is associated with increased heart rate (HR), as an index of heat production in all ambient temperatures. Although tail skin temperature (T(tail)) as an index of heat loss increased only under normal ambient temperatures, its response was relatively delayed in comparison with HR and T(b), suggesting that the increase in T(tail) was a secondary response to increased HR and T(b). Locomotor activity also increased in all ambient temperatures, but its response was not extraordinary. Interestingly, thermoregulatory responses were different after perfusion of GABA(A) antagonist bicuculline at each ambient temperature. In normal ambient temperature conditions, perfusion of bicuculline had no effect on any parameter. However, under cold ambient temperature, the procedure induced significant hypothermia concomitant with a decrease in HR in spite of hyperactivity and increase of T(tail). It induced hyperthermia with the increase of HR but no additional change of T(tail) in hot ambient temperature conditions. Furthermore, the extracellular GABA level increased significantly during cold exposure. Its release was lower during heat exposure than in a normal environment. These results indicate that GABA in the PO/AH is an important neurotransmitter for disinhibition of heat production and inhibition of heat loss under cold ambient temperature. It is a neurotransmitter for inhibition of heat production under hot ambient temperature.

Seismic and Aseismic Behavior of the Altotiberina Low-angle Normal Fault System (Northern Apennines, Italy) through High-resolution Earthquake Locations and Repeating Events

NASA Astrophysics Data System (ADS)

Valoroso, L.; Chiaraluce, L.

2017-12-01

Low-angle normal faults (dip < 30°) are geologically widely documented and considered responsible for accommodating the crustal extension within the brittle crust although their mechanical behavior and seismogenic potential is enigmatic. We study the anatomy and slip-behavior of the actively slipping Altotiberina low-angle (ATF) normal fault system using a high-resolution 5-years-long (2010-2014) earthquake catalogue composed of 37k events (ML<3.9 and completeness magnitude MC=0.5 ML), recorded by a dense permanent seismic network of the Altotiberina Near Fault Observatory (TABOO). The seismic activity defines the fault system dominated at depth by the low-angle ATF surface (15-20°) coinciding to the ATF geometry imaged through seismic reflection data. The ATF extends for 50km along-strike and between 4-5 to 16km of depth. Seismicity also images the geometry of a set of higher angle faults (35-50°) located in the ATF hanging-wall (HW). The ATF-related seismicity accounts for 10% of the whole seismicity (3,700 events with ML<2.4), occurring at a remarkably constant rate of 2.2 events/day. This seismicity describes an about 1.5-km-thick fault zone composed by multiple sub-parallel slipping planes. The remaining events are instead organized in multiple mainshocks (MW>3) seismic sequences lasting from weeks to months, activating a contiguous network of 3-5-km-long syn- and antithetic fault segments within the ATF-HW. The space-time evolution of these minor sequences is consistent with subsequence failures promoted by fluid flow. The ATF-seismicity pattern includes 97 clusters of repeating events (RE) made of 299 events with ML<1.9. RE are located around locked patches identified by geodetic modeling, suggesting a mixed-mode (stick-slip and stable-sliding) slip-behavior along the fault plane in accommodating most of the NE-trending tectonic deformation with creeping dominating below 5 km depth. Consistently, the seismic moment released by the ATF-seismicity accounts for a small portion (30%) of the geodetic one. The rate of occurrence of RE, mostly composed by doublets with short inter-event time (e.g. hours), appears to modulate the seismic release of the ATF-HW, suggesting that creeping may drive the strain partitioning of the system.

Does infection tilt the scales? Disease effects on the mass balance of an invertebrate nutrient recycler.

PubMed

Narr, Charlotte F; Frost, Paul C

2015-12-01

While parasites are increasingly recognized as important components of ecosystems, we currently know little about how they alter ecosystem nutrient availability via host-mediated nutrient cycling. We examined whether infection alters the flow of nutrients through hosts and whether such effects depend upon host diet quality. To do so, we compared the mass specific nutrient (i.e., nitrogen and phosphorus) release rates, ingestion rates, and elemental composition of uninfected Daphnia to those infected with a bacterial parasite, P. ramosa. N and P release rates were increased by infection when Daphnia were fed P-poor diets, but we found no effect of infection on the nutrient release of individuals fed P-rich diets. Calculations based on the first law of thermodynamics indicated that infection should increase the nutrient release rates of Daphnia by decreasing nutrient accumulation rates in host tissues. Although we found reduced nutrient accumulation rates in infected Daphnia fed all diets, this reduction did not increase the nutrient release rates of Daphnia fed the P-rich diet because infected Daphnia fed this diet ingested nutrients more slowly than uninfected hosts. Our results thus indicate that parasites can significantly alter the nutrient use of animal consumers, which could affect the availability of nutrients in heavily parasitized environments.

Dissolution kinetics of iron-, manganese-, and copper-containing synthetic hydroxyapatites

NASA Technical Reports Server (NTRS)

Sutter, B.; Hossner, L. R.; Ming, D. W.

2005-01-01

Micronutrient-substituted synthetic hydroxyapatite (SHA) is being evaluated by the National Aeronautics and Space Administration's (NASA) Advanced Life Support (ALS) Program for crop production on long-duration human missions to the International Space Station or for future Lunar or Martian outposts. The stirred-flow technique was utilized to characterize Ca, P, Fe, Mn, and Cu release characteristics from Fe-, Mn-, and Cu-containing SHA in deionized (DI) water, citric acid, and diethylene-triamine-pentaacetic acid (DTPA). Initially, Ca and P release rates decreased rapidly with time and were controlled by a non-SHA calcium phosphate phase(s) with low Ca/P solution molar ratios (0.91-1.51) relative to solid SHA ratios (1.56-1.64). At later times, Ca/P solution molar ratios (1.47-1.79) were near solid SHA ratios and release rates decreased slowly indicating that SHA controlled Ca and P release. Substituted SHA materials had faster dissolution rates relative to unsubstituted SHA. The initial metal release rate order was Mn >> Cu > Fe which followed metal-oxide/phosphate solubility suggesting that poorly crystalline metal-oxides/phosphates were dominating metal release. Similar metal release rates for all substituted SHA (approximately 0.01 cmol kg-1 min-1) at the end of the DTPA experiment indicated that SHA dissolution was supplying the metals into solution and that poorly crystalline metal-oxide/phosphates were not controlling metal release. Results indicate that non-SHA Ca-phosphate phases and poorly crystalline metal-oxide/phosphates will contribute Ca, P, and metals. After these phases have dissolved, substituted SHA will be the source of Ca, P, and metals for plants.

Different growth hormone (GH) response to GH-releasing peptide and GH-releasing hormone in hyperthyroidism.

PubMed

Ramos-Dias, J C; Pimentel-Filho, F; Reis, A F; Lengyel, A M

1996-04-01

Altered GH responses to several pharmacological stimuli, including GHRH, have been found in hyperthyroidism. The mechanisms underlying these disturbances have not been fully elucidated. GH-releasing peptide-6 (GHRP-6) is a synthetic hexapeptide that specifically stimulates GH release both in vitro and in vivo. The mechanism of action of GHRP-6 is unknown, but it probably acts by inhibiting the effects of somatostatin on GH release. The aim of this study was to evaluate the effects of GHRP-6 on GH secretion in patients with hyperthyroidism (n = 9) and in control subjects (n = 9). Each subject received GHRP-6 (1 microg/kg, iv), GHRH (100 microg, iv), and GHRP-6 plus GHRH on 3 separate days. GH peak values (mean +/- SE; micrograms per L) were significantly lower in hyperthyroid patients compared to those in control subjects after GHRH alone (9.0 +/- 1.3 vs. 27.0 +/- 5.2) and GHRP-6 plus GHRH (22.5 +/- 3.5 vs. 83.7 +/- 15.2); a lack of the normal synergistic effect of the association of both peptides was observed in thyrotoxicosis. However, a similar GH response was seen in both groups after isolated GHRP-6 injection (31.9 +/- 5.7 vs. 23.2 +/- 3.9). In summary, we have shown that hyperthyroid patients have a normal GH response to GHRP-6 together with a blunted GH responsiveness to GHRH. Our data suggest that thyroid hormones modulate GH release induced by these two peptides in a differential way.

Phosphatidylinositol 3-kinase inhibition restores Ca2+ release defects and prolongs survival in myotubularin-deficient mice

PubMed Central

Kutchukian, Candice; Lo Scrudato, Mirella; Tourneur, Yves; Poulard, Karine; Vignaud, Alban; Berthier, Christine; Allard, Bruno; Lawlor, Michael W.; Buj-Bello, Ana; Jacquemond, Vincent

2016-01-01

Mutations in the gene encoding the phosphoinositide 3-phosphatase myotubularin (MTM1) are responsible for a pediatric disease of skeletal muscle named myotubular myopathy (XLMTM). Muscle fibers from MTM1-deficient mice present defects in excitation–contraction (EC) coupling likely responsible for the disease-associated fatal muscle weakness. However, the mechanism leading to EC coupling failure remains unclear. During normal skeletal muscle EC coupling, transverse (t) tubule depolarization triggers sarcoplasmic reticulum (SR) Ca2+ release through ryanodine receptor channels gated by conformational coupling with the t-tubule voltage-sensing dihydropyridine receptors. We report that MTM1 deficiency is associated with a 60% depression of global SR Ca2+ release over the full range of voltage sensitivity of EC coupling. SR Ca2+ release in the diseased fibers is also slower than in normal fibers, or delayed following voltage activation, consistent with the contribution of Ca2+-gated ryanodine receptors to EC coupling. In addition, we found that SR Ca2+ release is spatially heterogeneous within myotubularin-deficient muscle fibers, with focally defective areas recapitulating the global alterations. Importantly, we found that pharmacological inhibition of phosphatidylinositol 3-kinase (PtdIns 3-kinase) activity rescues the Ca2+ release defects in isolated muscle fibers and increases the lifespan and mobility of XLMTM mice, providing proof of concept for the use of PtdIns 3-kinase inhibitors in myotubular myopathy and suggesting that unbalanced PtdIns 3-kinase activity plays a critical role in the pathological process. PMID:27911767

Normalization of doxorubicin release from graphene oxide: New approach for optimization of effective parameters on drug loading.

PubMed

Hashemi, Mohadeseh; Yadegari, Amir; Yazdanpanah, Ghasem; Omidi, Meisam; Jabbehdari, Sayena; Haghiralsadat, Fatemeh; Yazdian, Fatemeh; Tayebi, Lobat

2017-05-01

Graphene oxide (GO) has been recently introduced as a suitable anticancer drug carrier, which could be loaded with doxorubicin (DOX) as a general chemotherapy agent. Herein, the attempts were made to optimize the effective parameters on both loading and release of DOX on GO. GO and GO-DOX were characterized using transition electron microscopy , zeta potential, Raman spectroscopy, UV-visible spectroscopy, and Fourier transform infrared spectroscopy. In addition, loading and releasing behaviors of DOX on GO were studied in terms of different temperature and pH values. The primary optimized values of pH and temperature for best-loaded amount of DOX were 8.9 and 309 K, respectively. Moreover, we found that the smallest amount of released DOX, in pH of cancer microenvironment (5.4), occurs when DOX had been previously loaded in pH 7.8 and 310 K. Although the highest amount of loaded DOX was in basic pH, the results of efficient release of DOX from the GO-DOX complex and also cellular toxicity assay revealed that the best pH for loading of DOX on GO was 7.8. Therefore, in addition to optimization of parameters for efficient loading of DOX on GO, this study suggested that normalization of a released drug compared with the amount of a loaded drug could be a new approach for optimization of drug loading on nanocarriers. © 2016 International Union of Biochemistry and Molecular Biology, Inc.

Plant litter decomposition and nutrient release in peatlands

NASA Astrophysics Data System (ADS)

Bragazza, Luca; Buttler, Alexandre; Siegenthaler, Andy; Mitchell, Edward A. D.

Decomposition of plant litter is a crucial process in controlling the carbon balance of peatlands. Indeed, as long as the rate of litter decomposition remains lower than the rate of above- and belowground litter production, a net accumulation of peat and, thus, carbon will take place. In addition, decomposition controls the release of important nutrients such as nitrogen, phosphorus, and potassium, the availability of which affects the structure and the functioning of plant communities. This chapter describes the role of the main drivers in affecting mass loss and nutrient release from recently deposited plant litter. In particular, the rate of mass loss of Sphagnum litter and vascular plant litter is reviewed in relation to regional climatic conditions, aerobic/anaerobic conditions, and litter chemistry. The rate of nutrient release is discussed in relation to the rate of mass loss and associated litter chemistry by means of a specific case study.

3D DNS of Turbulent Premixed Flame with over 50 Species and 300 Elementary Reactions

NASA Astrophysics Data System (ADS)

Shimura, Masayasu; Yenerdag, Basmil; Naka, Yoshitsugu; Nada, Yuzuru; Tanahashi, Mamoru

2014-11-01

Three-dimensional direct numerical simulation of methane-air premixed planar flame propagating in homogenous isotropic turbulence is conducted to investigate local flame structure in thin reaction zones. Detailed kinetic mechanism, GRI-Mech 3.0 which includes 53 species and 325 elementary reactions, is used to represent methane-air reaction, and temperature dependences of transport and thermal properties are considered. For a better understanding of the local flame structure in thin reaction zones regime, distributions of mass fractions of major species, heat release rate, temperature and turbulent structures are investigated. Characteristic flame structures, such as radical fingering and multi-layered-like flame structures, are observed. The most expected maximum heat release rate in flame elements is lower than that of laminar flame with same mixture. To clarify mechanism of the decrease in local heat release rate, effects of strain rates tangential to flame front on local heat release rate are investigated.

Acute turpentine inflammation and kinin release in rat-paw thermic oedema.

PubMed Central

Limãos, E. A.; Borges, D. R.; Souza-Pinto, J. C.; Gordon, A. H.; Prado, J. L.

1981-01-01

Livers from rats at 2-3 days after s.c. injection of turpentine, when perfused, synthesized prekallikrein nearly 3 times faster than did livers from normal rats. On the other hand paw oedema, produced by heating to 46 degrees, in rats injured in this way was less marked. Likewise in such rats the amount of bradykinin release by 50 min. of coaxial perfusion of the paw was only 13.6 +/- 4.6 compared with 63.1 +/- 13.4 ng in normal rats. A possible explanation for the observed reduction in production of bradykinin may be inhibition of kallikrein due to an increased concentration of alpha 2-macroglobulin. PMID:6173056

Versatile solid-state relay

NASA Technical Reports Server (NTRS)

Fox, D. A.

1977-01-01

Solid-state relay (SSR), containing multinode control logic, is operated as normally open, normally closed, or latched. Moreover several can be paralleled to form two-pole or double-throw relays. Versatile unit ends need to design custom control circuit for every relay application. Technique can be extended to incorporate selectable time delay, on operation or release, or pulsed output.

Dust release rates and dust-to-gas mass ratios of eight comets

NASA Technical Reports Server (NTRS)

Singh, P. D.; De Almeida, A. A.; Huebner, W. F.

1992-01-01

Mass release rates of dust and mass ratios of dust-to-gas release rates of Comets Thiele (1985m), Wilson (1986l), P/Borrelly (1987p), Liller (1988a), Bradfield (1987s), Hartley-Good (1985l), P/Giacobini-Zinner (1984e), and P/Halley (1982i) are estimated from the analysis of continuum flux measurements at optical wavelengths. An attempt is made to estimate the size of each comet nucleus on the basis of water-ice sublimation (vaporization), assuming that the nucleus is spherical and only a fraction of its surface area is active. Where possible, the dust mass release rates are compared with those obtained by other investigators in the optical and IR wavelength regions. Good agreement with results based on IR observations is found.

Differentiation Affects the Release of Exosomes from Colon Cancer Cells and Their Ability to Modulate the Behavior of Recipient Cells.

PubMed

Lucchetti, Donatella; Calapà, Federica; Palmieri, Valentina; Fanali, Caterina; Carbone, Federica; Papa, Alfredo; De Maria, Ruggero; De Spirito, Marco; Sgambato, Alessandro

2017-07-01

Exosomes are involved in intercellular communication. We previously reported that sodium butyrate-induced differentiation of HT29 colon cancer cells is associated with a reduced CD133 expression. Herein, we analyzed the role of exosomes in the differentiation of HT29 cells. Exosomes were prepared using ultracentrifugation. Gene expression levels were evaluated by real-time PCR. The cell proliferation rate was assessed by MTT assay and with the electric cell-substrate impedance sensing system, whereas cell motility was assessed using the scratch test and confocal microscopy. Sodium butyrate-induced differentiation of HT29 and Caco-2 cells increased the levels of released exosomes and their expression of CD133. Cell differentiation and the decrease of cellular CD133 expression levels were prevented by blocking multivesicular body maturation. Exosomes released by HT29 differentiating cells carried increased levels of miRNAs, induced an increased proliferation and motility of both colon cancer cells and normal fibroblasts, increased the colony-forming efficiency of cancer cells, and reduced the sodium butyrate-induced differentiation of HT29 cells. Such effects were associated with an increased phosphorylation level of both Src and extracellular signal regulated kinase proteins and with an increased expression of epithelial-to-mesenchymal transition-related genes. Release of exosomes is affected by differentiation of colon cancer cells; exosomes might be used by differentiating cells to get rid of components that are no longer necessary but might continue to exert their effects on recipient cells. Copyright © 2017 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Gas Release as a Deformation Signal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bauer, Stephen J.

Radiogenic noble gases are contained in crustal rock at inter and intra granular sites. The gas composition depends on lithology, geologic history, fluid phases, and the aging effect by decay of U, Th, and K. The isotopic signature of noble gases found in rocks is vastly different than that of the atmosphere which is contributed by a variety of sources. When rock is subjected to stress conditions exceeding about half its yield strength, micro-cracks begin to form. As rock deformation progresses a fracture network evolves, releasing trapped noble gases and changing the transport properties to gas migration. Thus, changes inmore » gas emanation and noble gas composition from rocks could be used to infer changes in stress-state and deformation. The purpose of this study has been to evaluate the effect of deformation/strain rate upon noble gas release. Four triaxial experiments were attempted for a strain rate range of %7E10-8 /s (180,000s) to %7E 10-4/s (500s); the three fully successful experiments (at the faster strain rates) imply the following: (1) helium is measurably released for all strain rates during deformation, this release is in amounts 1-2 orders of magnitude greater than that present in the air, and (2) helium gas release increases with decreasing strain rate.« less

Effect of amine functionalization of spherical MCM-41 and SBA-15 on controlled drug release

DOE Office of Scientific and Technical Information (OSTI.GOV)

Szegedi, A., E-mail: szegedi@chemres.h; Popova, M.; Goshev, I.

2011-05-15

MCM-41 and SBA-15 silica materials with spherical morphology and different particle sizes were synthesized and modified by post-synthesis method with 3-aminopropyltriethoxysilane (APTES). A comparative study of the adsorption and release of a model drug, ibuprofen, were carried out. The modified and drug loaded mesoporous materials were characterized by XRD, TEM, N{sub 2} physisorption, thermal analysis, elemental analysis and FT-IR spectroscopy. Surface modification with amino groups resulted in high degree of ibuprofen loading and slow rate of release for MCM-41, whereas it was the opposite for SBA-15. The adsorbed drug content and the delivery rate can be predetermined by the choicemore » of mesoporous material with the appropriate structural characteristics and surface functionality. -- Graphical Abstract: Ibuprofen delivery from the parent and amino-modified spherical MCM-41 materials with 100 nm (small) and 500 nm (large) particle sizes. Display Omitted Highlights: {yields} Spherical type MCM-41 and SBA-15 with different particle sizes were modified by APTES. {yields} Adsorption and release rate of ibuprofen were compared. {yields} High degree of ibuprofen loading, slow release rate for MCM-41, the opposite for SBA-15. {yields} MCM-41 with 100 nm particles was more stable and showed slower release rate« less

Biomechanics of conidial dispersal in the toxic mold Stachybotrys chartarum

PubMed Central

Tucker, Kathryn; Stolze, Jessica L.; Kennedy, Aaron H.; Money, Nicholas P.

2007-01-01

Conidial dispersal in Stachybotrys chartarum in response to low-velocity airflow was studied using a microflow apparatus. The maximum rate of spore release occurred during the first 5 min of airflow, followed by a dramatic reduction in dispersal that left more than 99% of the conidia attached to their conidiophores. Micromanipulation of undisturbed colonies showed that micronewton (μN) forces were needed to dislodge spore clusters from their supporting conidiophores. Calculations show that airspeeds that normally prevail in the indoor environment disturb colonies with forces that are 1,000-fold lower, in the nanonewton (nN) range. Low-velocity airflow does not, therefore, cause sufficient disturbance to disperse a large proportion of the conidia of S. chartarum. PMID:17267247

14 CFR 121.312 - Materials for compartment interiors.

Code of Federal Regulations, 2011 CFR

2011-01-01

... prior to August 20, 1990, must comply with the heat release rate testing provisions of § 25.853(d) in...), except that the total heat release over the first 2 minutes of sample exposure must not exceed 100 kilowatt minutes per square meter and the peak heat release rate must not exceed 100 kilowatts per square...

14 CFR 121.312 - Materials for compartment interiors.

Code of Federal Regulations, 2010 CFR

2010-01-01

... prior to August 20, 1990, must comply with the heat release rate testing provisions of § 25.853(d) in...), except that the total heat release over the first 2 minutes of sample exposure must not exceed 100 kilowatt minutes per square meter and the peak heat release rate must not exceed 100 kilowatts per square...

14 CFR 121.312 - Materials for compartment interiors.

Code of Federal Regulations, 2012 CFR

2012-01-01

... prior to August 20, 1990, must comply with the heat release rate testing provisions of § 25.853(d) in...), except that the total heat release over the first 2 minutes of sample exposure must not exceed 100 kilowatt minutes per square meter and the peak heat release rate must not exceed 100 kilowatts per square...

14 CFR 135.170 - Materials for compartment interiors.

Code of Federal Regulations, 2011 CFR

2011-01-01

... August 20, 1990, must comply with the heat release rate testing provisions of § 25.853(d) in effect March 6, 1995 (formerly § 25.853(a-1) in effect on August 20, 1986), except that the total heat release... and the peak heat release rate must not exceed 100 kilowatts per square meter. (ii) Each airplane with...

14 CFR 135.170 - Materials for compartment interiors.

Code of Federal Regulations, 2012 CFR

2012-01-01

... August 20, 1990, must comply with the heat release rate testing provisions of § 25.853(d) in effect March 6, 1995 (formerly § 25.853(a-1) in effect on August 20, 1986), except that the total heat release... and the peak heat release rate must not exceed 100 kilowatts per square meter. (ii) Each airplane with...

14 CFR 121.312 - Materials for compartment interiors.

Code of Federal Regulations, 2013 CFR

2013-01-01

... prior to August 20, 1990, must comply with the heat release rate testing provisions of § 25.853(d) in...), except that the total heat release over the first 2 minutes of sample exposure must not exceed 100 kilowatt minutes per square meter and the peak heat release rate must not exceed 100 kilowatts per square...

14 CFR 135.170 - Materials for compartment interiors.

Code of Federal Regulations, 2014 CFR

2014-01-01

... August 20, 1990, must comply with the heat release rate testing provisions of § 25.853(d) in effect March 6, 1995 (formerly § 25.853(a-1) in effect on August 20, 1986), except that the total heat release... and the peak heat release rate must not exceed 100 kilowatts per square meter. (ii) Each airplane with...

14 CFR 135.170 - Materials for compartment interiors.

Code of Federal Regulations, 2013 CFR

2013-01-01

... August 20, 1990, must comply with the heat release rate testing provisions of § 25.853(d) in effect March 6, 1995 (formerly § 25.853(a-1) in effect on August 20, 1986), except that the total heat release... and the peak heat release rate must not exceed 100 kilowatts per square meter. (ii) Each airplane with...

14 CFR 121.312 - Materials for compartment interiors.

Code of Federal Regulations, 2014 CFR

2014-01-01

... prior to August 20, 1990, must comply with the heat release rate testing provisions of § 25.853(d) in...), except that the total heat release over the first 2 minutes of sample exposure must not exceed 100 kilowatt minutes per square meter and the peak heat release rate must not exceed 100 kilowatts per square...

14 CFR 135.170 - Materials for compartment interiors.

Code of Federal Regulations, 2010 CFR

2010-01-01

... August 20, 1990, must comply with the heat release rate testing provisions of § 25.853(d) in effect March 6, 1995 (formerly § 25.853(a-1) in effect on August 20, 1986), except that the total heat release... and the peak heat release rate must not exceed 100 kilowatts per square meter. (ii) Each airplane with...

The Relationship between Toxics Release Inventory Discharges and Mortality Rates in Rural and Urban Areas of the United States

ERIC Educational Resources Information Center

Hendryx, Michael; Fedorko, Evan

2011-01-01

Background: Potential environmental exposures from chemical manufacturing or industrial sites have not been well studied for rural populations. The current study examines whether chemical releases from facilities monitored through the Toxics Release Inventory (TRI) program are associated with population mortality rates for both rural and urban…

The sludge loading rate regulates the growth and release of heterotrophic bacteria resistant to six types of antibiotics in wastewater activated sludge.

PubMed

Yuan, Qing-Bin; Guo, Mei-Ting; Yang, Jian

2015-01-01

Wastewater treatment plants are considered as hot reservoirs of antimicrobial resistance. However, the fates of antibiotic-resistant bacteria during biological treatment processes and relevant influencing factors have not been fully understood. This study evaluated the effects of the sludge loading rate on the growth and release of six kinds of antibiotic-resistant bacteria in an activated sludge system. The results indicated that higher sludge loading rates amplified the growth of all six types of antibiotic resistant bacteria. The release of most antibiotic-resistant bacteria through both the effluent and biosolids was amplified with increased sludge loading rate. Biosolids were the main pattern for all antibiotic-resistant bacteria release in an activated sludge system, which was determined primarily by their growth in the activated sludge. A higher sludge loading rate reactor tended to retain more antibiotic resistance. An activated sludge system with lower sludge loading rates was considered more conducive to the control of antibiotic resistance.

Reduction of calcium inactivation of sarcoplasmic reticulum calcium release by fura-2 in voltage-clamped cut twitch fibers from frog muscle

PubMed Central

1993-01-01

Cut fibers from Rana temporaria and Rana pipiens (striation spacing, 3.9-4.2 microns) were mounted in a double Vaseline-gap chamber and studied at 14 degrees C. The Ca indicator purpurate-3,3' diacetic acid (PDAA) was introduced into the end pools and allowed to diffuse into the optical recording site. When the concentration at the site exceeded 2 mM, step depolarizations to 10 mV were applied and the [Ca] transient measured with PDAA was used to estimate Ca release from the sarcoplasmic reticulum (SR) (Baylor, S. M., W. K. Chandler, and M. W. Marshall. 1983. Journal of Physiology. 344:625-666). With depolarization, the rate of SR Ca release increased to an early peak and then rapidly decreased several-fold to a quasi-steady level. The total amount of Ca released from the SR at the time of peak rate of release appeared to be independent of SR Ca content, consistent with the idea that a single activated channel might pass, on average, a fixed number of ions, independent of the magnitude of the single channel flux. A possible explanation of this property is given in terms of locally induced Ca inactivation of Ca release. The solution in the end pools was then changed to one with PDAA plus fura-2. SR Ca release was estimated from the [Ca] transient, as before, and from the delta [Cafura-2] signal. On average, 2-3 mM fura-2 increased the quasi-steady level of the rate of SR Ca release by factors of 6.6 and 3.8, respectively, in three fibers from Rana temporaria and three fibers from Rana pipiens. The peak rate of release was increased in five of the six fibers but to a lesser extent than the quasi-steady level. In all fibers, the amplitude of the free [Ca] transient was markedly reduced. These increases in the rate of SR Ca release are consistent with the idea that Ca inactivation of Ca release develops during a step depolarization to 10 mV and that 2-3 mM fura-2 is able to reduce this inactivation by complexing Ca and thereby reducing free [Ca]. Once the concentration of fura-2 becomes sufficiently large, a further increase reduces the rate of SR Ca release. On average, 5-6 mM fura-2 increased the quasi-steady rate of release, compared with 0 mM fura-2, by 6.5 and 2.9, respectively, in four fibers from Rana temporaria and three from Rana pipiens.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:8228914

Chemical durability and leaching mechanism of Ce0.5Eu0.5PO4 ceramics: Effects of temperature and pH values

NASA Astrophysics Data System (ADS)

Zhao, Xiaofeng; Teng, Yuancheng; Wu, Lang; Huang, Yi; Ma, Jiyan; Wang, Guolong

2015-11-01

Ce0.5Eu0.5PO4 ceramics with high relative density were prepared by hot-press (HPS) and pressureless (PLS) sintering. The effects of temperature and pH values on the chemical durability of the ceramics were investigated. The results show that an increase of acidity significantly accelerated the corrosion of the samples. In alkaline leachates, further release elements were prevented by the newborn surface precipitation. The leach rate (Rn) of HPS sample was similar to that of PLS specimen in deionized water, but higher Rn for PLS sample was found in pH = 11 solution. Moreover, apparent activation energy of the dissolution of Eu (40 ± 4 kJ mol-1) is much higher than that of Ce (20 ± 1 kJ mol-1), leading to the higher normalized elemental leach rate of Eu. Both the Eu and Ce elements have low leach rates (10-12-10-9 m d-1) after 42 days in all the leachates studied in this work.

Evidence that the tri-cellular metabolism of N-acetylaspartate functions as the brain's "operating system": how NAA metabolism supports meaningful intercellular frequency-encoded communications.

PubMed

Baslow, Morris H

2010-11-01

N-acetylaspartate (NAA), an acetylated derivative of L-aspartate (Asp), and N-acetylaspartylglutamate (NAAG), a derivative of NAA and L-glutamate (Glu), are synthesized by neurons in brain. However, neurons cannot catabolize either of these substances, and so their metabolism requires the participation of two other cell types. Neurons release both NAA and NAAG to extra-cellular fluid (ECF) upon stimulation, where astrocytes, the target cells for NAAG, hydrolyze it releasing NAA back into ECF, and oligodendrocytes, the target cells for NAA, hydrolyze it releasing Asp to ECF for recycling to neurons. This sequence is unique as it is the only known amino acid metabolic cycle in brain that requires three cell types for its completion. The results of this cycling are two-fold. First, neuronal metabolic water is transported to ECF for its removal from brain. Second, the rate of neuronal activity is coupled with focal hyperemia, providing stimulated neurons with the energy required for transmission of meaningful frequency-encoded messages. In this paper, it is proposed that the tri-cellular metabolism of NAA functions as the "operating system" of the brain, and is essential for normal cognitive and motor activities. Evidence in support of this hypothesis is provided by the outcomes of two human inborn errors in NAA metabolism.

Role of cardiac volume receptors in the control of ADH release during acute simulated weightlessness in man

NASA Technical Reports Server (NTRS)

Convertino, V. A.; Benjamin, B. A.; Keil, L. C.; Sandler, H.

1984-01-01

Hemodynamic responses and antidiuretic hormone (ADH) were measured during body position changes, designed to induce central blood volume shifts in ten cardiac and one heart-lung transplant recipients, to assess the contribution of cardiac volume receptors in the control of ADH release during the initial acute phase of exposure to weightlessness. Each subject underwent 15 min of a sitting-control period (C) followed by 30 min of 6 deg headdown tilt (T) and 30 min of resumed sitting (S). Venous blood samples and cardiac dimensions were taken at 0 and 15 min of C; 5, 15, and 30 min of T; and 5, 15, and 30 min of S. Blood samples were analyzed for hematocrit, plasma osmolality, plasma renin activity (PRA), and ADH. Heart rate and blood pressure were recorded every two min. Plasma osmolality was not altered by posture changes. Mean left ventricular end-diastolic volume increased (P less than 0.05) from 90 ml in C to 106 ml in T and returned to 87 ml in S. Plasma ADH was reduced by 20 percent (P less than 0.05) with T, and returned to control levels with S. These responses were similar in six normal cardiac-innervated control subjects. These data may suggest that cardiac volume receptors are not the primary mechanism for the control of ADH release during acute central volume shifts in man.

Development and evaluation of emulsion-liposome blends for resveratrol delivery.

PubMed

Hung, Chi-Feng; Chen, Jan-Kan; Liao, Mei-Hui; Lo, Huey-Ming; Fang, Jia-You

2006-01-01

Nano- and submicron-sized vesicles are beneficial for the controlled delivery of drugs. Resveratrol, the main active polyphenol in red wine, was incorporated into various combinations of emulsions and liposomes to examine its physicochemical characteristics and cardiovascular protection. The blends of emulsion-liposome were composed of coconut oil, soybean lecithin, glycerol formal, and non-ionic surfactants. Multiple systems were assessed by evaluating the droplet size, surface charge, drug encapsulation, release rate, and stability. The vesicle diameter of the systems ranged from 114 to 195 nm. The liposomal vesicles in the systems had smaller diameters (of 43 approximately 56 nm) (F6 and F7). Drug encapsulation of approximately 70% were achieved by the vesicles. The inclusion of resveratrol in these systems retarded the drug release in both the presence and absence of plasma in vitro. The emulsion-liposome blends which incorporated Brij 98 (F5) exhibited the slowest release at zero-order for resveratrol delivery. Treatment using resveratrol in the blended formulations dramatically inhibited vascular intimal thickening, which was tested in an experimental model in which endothelial injury was produced in normal rat carotid arteries. Intraperitoneal injection of the multiple systems was associated with no or negligible liver and kidney toxicity. We concluded that encapsulation by the emulsion-liposome blends is a potent way to enhance the preventative and therapeutic benefits of resveratrol.

A pH-responsive carboxymethyl dextran-based conjugate as a carrier of docetaxel for cancer therapy.

PubMed

Han, Hwa Seung; Lee, Minchang; An, Jae Yoon; Son, Soyoung; Ko, Hyewon; Lee, Hansang; Chae, Yee Soo; Kang, Young Mo; Park, Jae Hyung

2016-05-01

Although docetaxel is available for the treatment of various cancers, its clinical applications are limited by its poor water solubility and toxicity to normal cells, resulting in severe adverse effects. In this study, we synthesized a polymeric conjugate with an acid-labile ester linkage, consisting of carboxymethyl dextran (CMD) and docetaxel (DTX), as a potential anticancer drug delivery system. The conjugate exhibited sustained release of DTX in physiological buffer (pH 7.4), whereas its release rate increased remarkably under mildly acidic conditions (pH < 6.5), mimicking the intracellular environment. Cytotoxicity tests conducted in vitro demonstrated that the conjugate exhibited much higher toxicity to cancer cells under mildly acidic conditions than at physiological buffer (pH 7.4). These results implied that the ester linkage in the conjugate allowed for selective release of biologically active DTX under mildly acidic conditions. The in vivo biodistribution of a Cy5.5-labeled conjugate was observed using the noninvasive optical imaging technique after its systemic administration into tumor-bearing mice. The conjugate was effectively accumulated into the tumor site, which may have been because of an enhanced permeability and retention effect. In addition, in vivo antitumor efficacy of the conjugate was significantly higher than that of free DTX. Overall, the CMD-based conjugate might have promising potential as a carrier of DTX for cancer therapy. © 2015 Wiley Periodicals, Inc.

Correlates to colonizations of new patches by translocated populations of bighorn sheep

USGS Publications Warehouse

Singer, F.J.; Moses, M.E.; Bellew, S.; Sloan, W.

2000-01-01

By 1950, bighorn sheep were extirpated from large areas of their range. Most extant populations of bighorn sheep (Ovis canadensis) in the Intermountain West consist of <100 individuals occurring in a fragmented distribution across the landscape. Dispersal and successful colonizations of unoccupied habitat patches has been rarely reported, and, in particular, translocated populations have been characterized by limited population growth and limited dispersal rates. Restoration of the species is greatly assisted by dispersal and successful colonization of new patches within a metapopulation structure versus the existing scenario of negligible dispersal and fragmented, small populations. We investigated the correlates for the rate of colonizations of 79 suitable, but unoccupied, patches by 31 translocated populations of bighorn sheep released into nearby patches of habitat. Population growth rates of bighorn sheep in the release patches were correlated to Ne of the founder group, and early contact with a second released population in a nearby release patch (logistic regression, p = 0.08). Largest population size of all extant released populations in 1994 was correlated to potential Ne of the founder group, the number of different source populations represented in the founder, and early contact with a second released population (p = 0.016). Dispersal rates were 100% higher in rams than ewes (p = 0.001). Successful colonizations of unoccupied patches (n = 24 of 79 were colonized) were associated with rapid growth rates in the released population, years since release, larger area of suitable habitat in the release patch, larger population sizes, and a seasonal migratory tendency in the released population (p = 0.05). Fewer water barriers, more open vegetation and more rugged, broken terrain in the intervening habitat were also associated with colonizations (p = <0.05). We concluded that high dispersal rates and rapid reoccupation of large areas could occur if bighorn sheep are placed in large patches of habitat with few barriers to movements to other patches and with no domestic sheep present. Many restorations in the past that did not meet these criteria may have contributed to an insular population structure of bighorn sheep with limited observations of dispersal.

Correlates to colonizations of new patches by translocated populations of bighorn sheep

USGS Publications Warehouse

Singer, F.J.; Moses, M.E.; Bellew, S.; Sloan, W.

2000-01-01

By 1950, bighorn sheep were extirpated from large areas of their range. Most extant populations of bighorn sheep (Ovis canadensis) in the Intermountain West consist of <100 individuals occurring in a fragmented distribution across the landscape. Dispersal and successful colonizations of unoccupied habitat patches has been rarely reported, and, in particular, translocated populations have been characterized by limited population growth and limited dispersal rates. Restoration of the species is greatly assisted by dispersal and successful colonization of new patches within a metapopulation structure versus the existing scenario of negligible dispersal and fragmented, small populations. We investigated the correlates for the rate of colonizations of 79 suitable, but unoccupied, patches by 31 translocated populations of bighorn sheep released into nearby patches of habitat. Population growth rates of bighorn sheep in the release patches were correlated to Ne of the founder group, and early contact with a second released population in a nearby release patch (logistic regression, p = 0.08). Largest population size of all extant released populations in 1994 was correlated to potential Ne of the founder group, the number of different source populations represented in the founder, and early contact with a second released population (p = 0.016). Dispersal rates were 100% higher in rams than ewes (p = 0.001). Successful colonizations of unoccupied patches (n = 24 of 79 were colonized) were associated with rapid growth rates in the released population, years since release, larger area of suitable habitat in the release patch, larger population sizes, and a seasonal migratory tendency in the released population (p = 0.05). Fewer water barriers, more open vegetation and more rugged, broken terrain in the intervening habitat were also associated with colonizations (p = <0.05). We concluded that high dispersal rates and rapid reoccupation of large areas could occur if bighorn sheep are placed in large patches of habitat with few barriers to movements to other patches and with no domestic sheep present. Many restorations in the past that did not meet these criteria may have contributed to an insular population structure of bighorn sheep with limited observations of dispersal.

Release of Water Soluble Drugs from Dynamically Swelling POLY(2-HYDROXYETHYL Methacrylate - CO - Methacrylic Acid) Hydrogels.

NASA Astrophysics Data System (ADS)

Kou, Jim Hwai-Cher

In this study, ionizable copolymers of HEMA and methacrylic acid (MA) are investigated for their potential use in developing pH dependent oral delivery systems. Because of the MA units, these gels swell extensively at high pH. Since solute diffusion in the hydrophilic polymers depends highly on the water content of the matrix, it is anticipated that the release rate will be modulated by this pH induced swelling. From a practical point of view, the advantage of the present system is that one can minimize drug loss in the stomach and achieve a programmed release in intestine. This approach is expected to improve delivery of acid labile drugs or drugs that cause severe gastrointestinal side effects. This work mainly focuses on the basic understanding of the mechanism involved in drug release from the poly(HEMA -co- MA) gels, especially under dynamic swelling conditions. Equilibrium swelling is first characterized since water content is the major determinant of transport properties in these gels. Phenylpropanolamine (PPA) is chosen as the model drug for the release study and its diffusion characteristics in the gel matrix determined. The data obtained show that the PPA diffusivity follows the free volume theory of Yasuda, which explains the accelerating effect of swelling on drug release. A mathematical model based on a diffusion mechanism has been developed to describe PPA release from the swelling gels. Based on this model, several significant conclusions can be drawn. First, the release rate can be modulated by the aspect ratio of the cylindrical geometry, and this has a practical implication in dosage form design. Second, the release rate can be lowered quite considerably if the dimensional increase due to swelling is significant. Consequently, it is the balance between the drug diffusivity increase and the gel dimensional growth that determines the release rate from the swelling matrix. Third, quasi-steady release kinetics, which are characteristic of swelling release systems, can also be predicted by this model. PPA release from initially dry poly(HEMA -co- MA) gels has also been studied. The data show that the release rate is mainly controlled by the PPA loading level and quite insensitive to the methacrylic acid composition of the gels. These phenomena can be adequately explained by analyzing the transport resistances in the gels. The overall time scale of release from these gels were shown to be in the range which was suitable for oral controlled release applications. (Abstract shortened with permission of author.).

The Dynamics of Pheromone Gland Synthesis and Release: a Paradigm Shift for Understanding Sex Pheromone Quantity in Female Moths.

PubMed

Foster, Stephen P; Anderson, Karin G; Casas, Jérôme

2018-05-10

Moths are exemplars of chemical communication, especially with regard to specificity and the minute amounts they use. Yet, little is known about how females manage synthesis and storage of pheromone to maintain release rates attractive to conspecific males and why such small amounts are used. We developed, for the first time, a quantitative model, based on an extensive empirical data set, describing the dynamical relationship among synthesis, storage (titer) and release of pheromone over time in a moth (Heliothis virescens). The model is compartmental, with one major state variable (titer), one time-varying (synthesis), and two constant (catabolism and release) rates. The model was a good fit, suggesting it accounted for the major processes. Overall, we found the relatively small amounts of pheromone stored and released were largely a function of high catabolism rather than a low rate of synthesis. A paradigm shift may be necessary to understand the low amounts released by female moths, away from the small quantities synthesized to the (relatively) large amounts catabolized. Future research on pheromone quantity should focus on structural and physicochemical processes that limit storage and release rate quantities. To our knowledge, this is the first time that pheromone gland function has been modeled for any animal.

Tectonic and Structural Controls of Geothermal Activity in the Great Basin Region, Western USA

NASA Astrophysics Data System (ADS)

Faulds, J. E.; Hinz, N.; Kreemer, C. W.

2012-12-01

We are conducting a thorough inventory of structural settings of geothermal systems (>400 total) in the extensional to transtensional Great Basin region of the western USA. Most of the geothermal systems in this region are not related to upper crustal magmatism and thus regional tectonic and local structural controls are the most critical factors controlling the locations of the geothermal activity. A system of NW-striking dextral faults known as the Walker Lane accommodates ~20% of the North American-Pacific plate motion in the western Great Basin and is intimately linked to N- to NNE-striking normal fault systems throughout the region. Overall, geothermal systems are concentrated in areas with the highest strain rates within or proximal to the eastern and western margins of the Great Basin, with the high temperature systems clustering in transtensional areas of highest strain rate in the northwestern Great Basin. Enhanced extension in the northwestern Great Basin probably results from the northwestward termination of the Walker Lane and the concomitant transfer of dextral shear into west-northwest directed extension, thus producing a broad transtensional region. The capacity of geothermal power plants also correlates with strain rates, with the largest (hundreds of megawatts) along the Walker Lane or San Andreas fault system, where strain rates range from 10-100 nanostrain/yr to 1,000 nanostrain/yr, respectively. Lesser systems (tens of megawatts) reside in the Basin and Range (outside the Walker Lane), where local strain rates are typically < 10 nanostrain/yr. Of the 250+ geothermal fields catalogued, step-overs or relay ramps in normal fault zones serve as the most favorable setting, hosting ~32% of the systems. Such areas have multiple, overlapping fault strands, increased fracture density, and thus enhanced permeability. Other common settings include a) intersections between normal faults and strike-slip or oblique-slip faults (27%), where multiple minor faults connect major structures and fluids can flow readily through highly fractured, dilational quadrants, and b) normal fault terminations or tip-lines (22%), where horse-tailing generates closely-spaced faults and increased permeability. Other settings include accommodation zones (i.e., belts of intermeshing, oppositely dipping normal faults; 8%), major range-front faults (5-6%), and pull-aparts in strike-slip faults (4%). In addition, Quaternary faults lie within or near most systems. The relative scarcity of geothermal systems along displacement-maxima of major normal faults may be due to reduced permeability in thick zones of clay gouge and periodic release of stress in major earthquakes. Step-overs, terminations, intersections, and accommodation zones correspond to long-term, critically stressed areas, where fluid pathways are more likely to remain open in networks of closely-spaced, breccia-dominated fractures. These findings may help guide future exploration efforts, especially for blind geothermal systems, which probably comprise the bulk of the geothermal resources in the Great Basin.

Attitudes towards massage modify effects of manual therapy in breast cancer survivors: a randomised clinical trial with crossover design.

PubMed

Fernández-Lao, C; Cantarero-Villanueva, I; Díaz-Rodríguez, L; Cuesta-Vargas, A I; Fernández-Delas-Peñas, C; Arroyo-Morales, M

2012-03-01

Our aims were to investigate the immediate effect of myofascial release on heart rate variability and mood state, and the influence of attitude towards massage in breast cancer survivors with cancer-related fatigue. Twenty breast cancer survivors reporting moderate to high cancer-related fatigue participated in this crossover study. All patients presented to the laboratory at the same time of the day on two occasions separated by a 2-week interval. At each session, they received either a massage intervention or control intervention. Holter electrocardiogram recordings and Profile of Mood States questionnaire (six domains: tension-anxiety, depression-dejection, anger-hostility, vigour, fatigue, confusion) were obtained before and immediately after each intervention. The attitude towards massage scale was collected before the first session in all breast cancer survivors. The results showed a significant session × time interaction for standard deviation of the normal-to-normal interval (SDNN) (F= 5.063, P= 0.039), square root of mean squared differences of successive normal-to-normal intervals (RMSSD) (F= 8.273, P= 0.010), high-frequency component (HF) (F= 7.571, P= 0.013), but not for index heart rate variability (F= 3.451, P= 0.080), low-frequency component (LF) (F= 0.014, P= 0.997) and ratio LF/HF (F= 3.680, P= 0.072): significant increases in SDNN, RMSSD and HF domain (P < 0.05) were observed after the manual therapy intervention, with no changes after placebo (P > 0.6). No influence of the attitude scale on heart rate variability results was found. A significant session × time interaction was also found for fatigue (F= 5.101, P= 0.036) and disturbance of mood (F= 6.690, P= 0.018) scales of the Profile of Mood States: patients showed a significant decrease in fatigue and disturbance of mood (P < 0.001) after manual therapy, with no changes after placebo (P > 0.50). A significant influence of the attitude scale was observed in tension-anxiety, depression-dejection and anger-hostility scales. This controlled trial suggests that massage leads to an immediate increase of heart rate variability and an improvement in mood in breast cancer survivors with cancer-related fatigue. Further, the positive impact of massage on cancer-related fatigue is modulated by the attitude of the patient towards massage. © 2011 Blackwell Publishing Ltd.

Forest soil mineral weathering rates: use of multiple approaches

Treesearch

Randy K. Kolka; D.F. Grigal; E.A. Nater

1996-01-01

Knowledge of rates of release of base cations from mineral dissolution (weathering) is essential to understand ecosystem elemental cycling. Although much studied, rates remain enigmatic. We compared the results of four methods to determine cation (Ca + Mg + K) release rates at five forested soils/sites in the northcentral U.S.A. Our premise was that multiple...

The association between male-biased sex ratio and indicators of stress in red-spotted newts.

PubMed

Aspbury, Andrea S; Grayson, Kristine L; Fantaye, Selamawit; Nichols, Ian; Myers-Burton, Miranda; Ortiz-Mangual, Xavier; Gabor, Caitlin R

2017-05-01

In populations with a male-biased operational sex ratio, coercive mating by males can have fitness consequences for females. One component of reduced fitness for females in populations with a male-biased OSR may be greater activation of the stress response, resulting in higher corticosterone release rates (CORT; a glucocorticoid stress hormone in amphibians). We test the hypothesis that a male-biased sex ratio affects female activity and release rates of CORT and testosterone (T) in male and female red-spotted newts (Notophthalmus viridescens). First, we evaluated if chemical cues from a male-biased sex ratio affect activity and CORT release rates in females. We predicted that females exposed to chemical cues of three males would be less active and have higher CORT release rates than those exposed to chemical cues of one male. Second, we measured CORT release rates of red-spotted newts in field enclosures with either a male-biased or a female-biased sex ratio. We predicted that females in the male-biased treatment would have higher CORT and T release rates than those in a female-biased treatment, owing to higher levels of male harassment. We also predicted that males would have higher CORT and T release rates in male-biased treatments due to higher levels of male-male competition. Females were not less active in response to chemical cues from more males over fewer males, but there was a positive relationship between female activity and CORT when they were exposed to the cues of three males. We also found that females, but not males, in the male-biased sex ratio treatment had higher CORT and T release rates than those in the female-biased treatment. Our results support the hypothesis that a male-biased sex ratio leads to a higher stress response, which may underlie the observed decrease in immune function and body condition in previous work exposing female red-spotted newts to a male-biased sex ratio. This study furthers our understanding of the mechanistic basis for costs associated with a male-biased sex ratio in a pond-breeding amphibian. Copyright © 2017 Elsevier Inc. All rights reserved.

On use of CO{sub 2} chemiluminescence for combustion metrics in natural gas fired reciprocating engines.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gupta, S. B.; Bihari, B.; Biruduganti, M.

Flame chemiluminescence is widely acknowledged to be an indicator of heat release rate in premixed turbulent flames that are representative of gas turbine combustion. Though heat release rate is an important metric for evaluating combustion strategies in reciprocating engine systems, its correlation with flame chemiluminescence is not well studied. To address this gap an experimental study was carried out in a single-cylinder natural gas fired reciprocating engine that could simulate turbocharged conditions with exhaust gas recirculation. Crank angle resolved spectra (266-795 nm) of flame luminosity were measured for various operational conditions by varying the ignition timing for MBT conditions andmore » by holding the speed at 1800 rpm and Brake Mean effective Pressure (BMEP) at 12 bar. The effect of dilution on CO*{sub 2}chemiluminescence intensities was studied, by varying the global equivalence ratio (0.6-1.0) and by varying the exhaust gas recirculation rate. It was attempted to relate the measured chemiluminescence intensities to thermodynamic metrics of importance to engine research -- in-cylinder bulk gas temperature and heat release rate (HRR) calculated from measured cylinder pressure signals. The peak of the measured CO*{sub 2} chemiluminescence intensities coincided with peak pressures within {+-}2 CAD for all test conditions. For each combustion cycle, the peaks of heat release rate, spectral intensity and temperature occurred in that sequence, well separated temporally. The peak heat release rates preceded the peak chemiluminescent emissions by 3.8-9.5 CAD, whereas the peak temperatures trailed by 5.8-15.6 CAD. Such a temporal separation precludes correlations on a crank-angle resolved basis. However, the peak cycle heat release rates and to a lesser extent the peak cycle temperatures correlated well with the chemiluminescent emission from CO*{sub 2}. Such observations point towards the potential use of flame chemiluminescence to monitor peak bulk gas temperatures as well as peak heat release rates in natural gas fired reciprocating engines.« less

Age-group differences in speech identification despite matched audiometrically normal hearing: contributions from auditory temporal processing and cognition

PubMed Central

Füllgrabe, Christian; Moore, Brian C. J.; Stone, Michael A.

2015-01-01

Hearing loss with increasing age adversely affects the ability to understand speech, an effect that results partly from reduced audibility. The aims of this study were to establish whether aging reduces speech intelligibility for listeners with normal audiograms, and, if so, to assess the relative contributions of auditory temporal and cognitive processing. Twenty-one older normal-hearing (ONH; 60–79 years) participants with bilateral audiometric thresholds ≤ 20 dB HL at 0.125–6 kHz were matched to nine young (YNH; 18–27 years) participants in terms of mean audiograms, years of education, and performance IQ. Measures included: (1) identification of consonants in quiet and in noise that was unmodulated or modulated at 5 or 80 Hz; (2) identification of sentences in quiet and in co-located or spatially separated two-talker babble; (3) detection of modulation of the temporal envelope (TE) at frequencies 5–180 Hz; (4) monaural and binaural sensitivity to temporal fine structure (TFS); (5) various cognitive tests. Speech identification was worse for ONH than YNH participants in all types of background. This deficit was not reflected in self-ratings of hearing ability. Modulation masking release (the improvement in speech identification obtained by amplitude modulating a noise background) and spatial masking release (the benefit obtained from spatially separating masker and target speech) were not affected by age. Sensitivity to TE and TFS was lower for ONH than YNH participants, and was correlated positively with speech-in-noise (SiN) identification. Many cognitive abilities were lower for ONH than YNH participants, and generally were correlated positively with SiN identification scores. The best predictors of the intelligibility of SiN were composite measures of cognition and TFS sensitivity. These results suggest that declines in speech perception in older persons are partly caused by cognitive and perceptual changes separate from age-related changes in audiometric sensitivity. PMID:25628563

Composite poly(vinyl alcohol)/poly(vinyl acetate) electrospun nanofibrous mats as a novel wound dressing matrix for controlled release of drugs

PubMed Central

Jannesari, Marziyeh; Varshosaz, Jaleh; Morshed, Mohammad; Zamani, Maedeh

2011-01-01

The aim of this study was to develop novel biomedicated nanofiber electrospun mats for controlled drug release, especially drug release directly to an injury site to accelerate wound healing. Nanofibers of poly(vinyl alcohol) (PVA), poly(vinyl acetate) (PVAc), and a 50:50 composite blend, loaded with ciprofloxacin HCl (CipHCl), were successfully prepared by an electrospinning technique for the first time. The morphology and average diameter of the electrospun nanofibers were investigated by scanning electron microscopy. X-ray diffraction studies indicated an amorphous distribution of the drug inside the nanofiber blend. Introducing the drug into polymeric solutions significantly decreased solution viscosities as well as nanofiber diameter. In vitro drug release evaluations showed that both the kind of polymer and the amount of drug loaded greatly affected the degree of swelling, weight loss, and initial burst and rate of drug release. Blending PVA and PVAc exhibited a useful and convenient method for electrospinning in order to control the rate and period of drug release in wound healing applications. Also, the thickness of the blend nanofiber mats strongly influenced the initial release and rate of drug release. PMID:21720511

Study of the influence of fuel load and slope on a fire spreading across a bed of pine needles by using oxygen consumption calorimetry

NASA Astrophysics Data System (ADS)

Tihay, V.; Morandini, F.; Santoni, P. A.; Perez-Ramirez, Y.; Barboni, T.

2012-11-01

A set of experiments using a Large Scale Heat Release Rate Calorimeter was conducted to test the effects of slope and fuel load on the fire dynamics. Different parameters such as the geometry of the flame front, the rate of spread, the mass loss rate and the heat release rate were investigated. Increasing the fuel load or the slope modifies the fire behaviour. As expected, the flame length and the rate of spread increase when fuel load or slope increases. The heat release rate does not reach a quasi-steady state when the propagation takes place with a slope of 20° and a high fuel load. This is due to an increase of the length of the fire front leading to an increase of fuel consumed. These considerations have shown that the heat release can be estimated with the mass loss rate by considering the effective heat of combustion. This approach can be a good alternative to estimate accurately the fireline intensity when the measure of oxygen consumption is not possible.

Subconjunctivally Implanted Hydrogels for Sustained Insulin Release to Reduce Retinal Cell Apoptosis in Diabetic Rats.

PubMed

Imai, Hisanori; Misra, Gauri P; Wu, Linfeng; Janagam, Dileep R; Gardner, Thomas W; Lowe, Tao L

2015-12-01

Diabetic retinopathy (DR) is a leading cause of blindness in diabetic patients that involves early-onset retinal cell loss. Here, we report our recent work using subconjunctivally implantable hydrogels for sustained insulin release to the retina to prevent retinal degeneration. The hydrogels are synthesized by UV photopolymerization of N-isopropylacrylamide and a dextran macromer containing oligolactate-(2-hydroxyetheyl methacrylate) units. Insulin was loaded into the hydrogels during the synthesis. The ex vivo bioactivity of insulin released from the hydrogels was tested on fresh rat retinas using immunoprecipitation and immunoblotting to measure insulin receptor tyrosine and Akt phosphorylation. The biosafety and the effect on the blood glucose of the hydrogels were evaluated in rats 2 months after subconjunctival implantation. The release of insulin from the hydrogels was studied both in vitro in PBS (pH 7.4), and in vivo using confocal microscopy and RIA kit. The in vivo bioactivity of the released insulin was investigated in diabetic rats using DNA fragmentation method. The hydrogels could load insulin with approximately 98% encapsulation efficiency and continuously release FITC-insulin in PBS (pH = 7.4) at 37°C for at least 5 months depending on their composition. Insulin lispro released from the hydrogels was biologically active by increasing insulin receptor tyrosine and Akt serine phosphorylation of ex vivo retinas. In vivo studies showed normal retinal histology 2 months post subconjunctival implantation. Insulin released from subconjunctivally implanted hydrogels could be detected in the retina by using confocal microscopy and RIA kit for 1 week. The implanted hydrogels with insulin lispro did not change the blood glucose level of normal and diabetic rats, but significantly reduced the DNA fragmentation of diabetic retinas for 1 week. The developed hydrogels have great potential to sustain release of insulin to the retina via subconjunctival implantation to minimize DR without the risk of hypoglycemia.

Subconjunctivally Implanted Hydrogels for Sustained Insulin Release to Reduce Retinal Cell Apoptosis in Diabetic Rats

PubMed Central

Imai, Hisanori; Misra, Gauri P.; Wu, Linfeng; Janagam, Dileep R.; Gardner, Thomas W.; Lowe, Tao L.

2015-01-01

Purpose Diabetic retinopathy (DR) is a leading cause of blindness in diabetic patients that involves early-onset retinal cell loss. Here, we report our recent work using subconjunctivally implantable hydrogels for sustained insulin release to the retina to prevent retinal degeneration. Methods The hydrogels are synthesized by UV photopolymerization of N-isopropylacrylamide and a dextran macromer containing oligolactate-(2-hydroxyetheyl methacrylate) units. Insulin was loaded into the hydrogels during the synthesis. The ex vivo bioactivity of insulin released from the hydrogels was tested on fresh rat retinas using immunoprecipitation and immunoblotting to measure insulin receptor tyrosine and Akt phosphorylation. The biosafety and the effect on the blood glucose of the hydrogels were evaluated in rats 2 months after subconjunctival implantation. The release of insulin from the hydrogels was studied both in vitro in PBS (pH 7.4), and in vivo using confocal microscopy and RIA kit. The in vivo bioactivity of the released insulin was investigated in diabetic rats using DNA fragmentation method. Results The hydrogels could load insulin with approximately 98% encapsulation efficiency and continuously release FITC-insulin in PBS (pH = 7.4) at 37°C for at least 5 months depending on their composition. Insulin lispro released from the hydrogels was biologically active by increasing insulin receptor tyrosine and Akt serine phosphorylation of ex vivo retinas. In vivo studies showed normal retinal histology 2 months post subconjunctival implantation. Insulin released from subconjunctivally implanted hydrogels could be detected in the retina by using confocal microscopy and RIA kit for 1 week. The implanted hydrogels with insulin lispro did not change the blood glucose level of normal and diabetic rats, but significantly reduced the DNA fragmentation of diabetic retinas for 1 week. Conclusions The developed hydrogels have great potential to sustain release of insulin to the retina via subconjunctival implantation to minimize DR without the risk of hypoglycemia. PMID:26658505

Sustained Release Drug Delivery Applications of Polyurethanes.

PubMed

Lowinger, Michael B; Barrett, Stephanie E; Zhang, Feng; Williams, Robert O

2018-05-09

Since their introduction over 50 years ago, polyurethanes have been applied to nearly every industry. This review describes applications of polyurethanes to the development of modified release drug delivery. Although drug delivery research leveraging polyurethanes has been ongoing for decades, there has been renewed and substantial interest in the field in recent years. The chemistry of polyurethanes and the mechanisms of drug release from sustained release dosage forms are briefly reviewed. Studies to assess the impact of intrinsic drug properties on release from polyurethane-based formulations are considered. The impact of hydrophilic water swelling polyurethanes on drug diffusivity and release rate is discussed. The role of pore formers in modulating drug release rate is examined. Finally, the value of assessing mechanical properties of the dosage form and approaches taken in the literature are described.

Floating tablets for controlled release of ofloxacin via compression coating of hydroxypropyl cellulose combined with effervescent agent.

PubMed

Qi, Xiaole; Chen, Haiyan; Rui, Yao; Yang, Fengjiao; Ma, Ning; Wu, Zhenghong

2015-07-15

To prolong the residence time of dosage forms within gastrointestinal trace until all drug released at desired rate was one of the real challenges for oral controlled-release drug delivery system. Herein, we developed a fine floating tablet via compression coating of hydrophilic polymer (hydroxypropyl cellulose) combined with effervescent agent (sodium bicarbonate) to achieve simultaneous control of release rate and location of ofloxacin. Sodium alginate was also added in the coating layer to regulate the drug release rate. The effects of the weight ratio of drug and the viscosity of HPC on the release profile were investigated. The optimized formulations were found to immediately float within 30s and remain lastingly buoyant over a period of 12 h in simulated gastric fluid (SGF, pH 1.2) without pepsin, indicating a satisfactory floating and zero-order drug release profile. In addition, the oral bioavailability experiment in New Zealand rabbits showed that, the relative bioavailability of the ofloxacin after administrated of floating tablets was 172.19%, compared to marketed common release tablets TaiLiBiTuo(®). These results demonstrated that those controlled-released floating tables would be a promising gastro-retentive delivery system for drugs acting in stomach. Copyright © 2015 Elsevier B.V. All rights reserved.

Percutaneous release of the plantar fascia. New surgical procedure.

PubMed

Oliva, Francesco; Piccirilli, Eleonora; Tarantino, Umberto; Maffulli, Nicola

2017-01-01

Plantar fasciopathy presents with pain at the plantar and medial aspect of the heel. If chronic, it can negatively impact on quality of life. Plantar fasciopathy is not always self-limiting, and can be debilitating. Surgical management involves different procedures. We describe a percutaneous plantar fascia release. A minimally invasive access to the plantar tuberosity of the calcaneus is performed, and a small scalpel blade is used to release the fascia. With this procedure, skin healing problems, nerve injuries, infection and prolonged recovery time are minimised, allowing early return to normal activities. V.

Investigating the role of ion-pair strategy in regulating nicotine release from patch: Mechanistic insights based on intermolecular interaction and mobility of pressure sensitive adhesive.

PubMed

Li, Qiaoyun; Wan, Xiaocao; Liu, Chao; Fang, Liang

2018-07-01

The aim of this study was to prepare a drug-in-adhesive patch of nicotine (NIC) and use ion-pair strategy to regulate drug delivery rate. Moreover, the mechanism of how ion-pair strategy regulated drug release was elucidated at molecular level. Formulation factors including pressure sensitive adhesives (PSAs), drug loading and counter ions (C 4 , C 6 , C 8 , C 10 , and C 12 ) were screened. In vitro release experiment and in vitro transdermal experiment were conducted to determine the rate-limiting step in drug delivery process. FT-IR and molecular modeling were used to characterize the interaction between drug and PSA. Thermal analysis and rheology study were conducted to investigate the mobility variation of PSA. The optimized patch prepared with NIC-C 8 had the transdermal profile fairly close to that of the commercial product (p > 0.05). The release rate constants (k) of NIC, NIC-C 4 and NIC-C 10 were 21.1, 14.4 and 32.4, respectively. Different release rates of NIC ion-pair complexes were attributed to the dual effect of ion-pair strategy on drug release. On one hand, ion-pair strategy enhanced the interaction between drug and PSA, which inhibited drug release. On the other hand, using ion-pair strategy improved the mobility of PSA, which facilitated drug release. Drug release behavior was determined by combined effect of two aspects above. These conclusions provided a new idea for us to regulate drug release behavior from patch. Copyright © 2018 Elsevier B.V. All rights reserved.

Influence of heat and shear induced protein aggregation on the in vitro digestion rate of whey proteins.

PubMed

Singh, Tanoj K; Øiseth, Sofia K; Lundin, Leif; Day, Li

2014-11-01

Protein intake is essential for growth and repair of body cells, the normal functioning of muscles, and health related immune functions. Most food proteins are consumed after undergoing various degrees of processing. Changes in protein structure and assembly as a result of processing impact the digestibility of proteins. Research in understanding to what extent the protein structure impacts the rate of proteolysis under human physiological conditions has gained considerable interest. In this work, four whey protein gels were prepared using heat processing at two different pH values, 6.8 and 4.6, with and without applied shear. The gels showed different protein network microstructures due to heat induced unfolding (at pH 6.8) or lack of unfolding, thus resulting in fine stranded protein networks. When shear was applied during heating, particulate protein networks were formed. The differences in the gel microstructures resulted in considerable differences in their rheological properties. An in vitro gastric and intestinal model was used to investigate the resulting effects of these different gel structures on whey protein digestion. In addition, the rate of digestion was monitored by taking samples at various time points throughout the in vitro digestion process. The peptides in the digesta were profiled using SDS-polyacrylamide gel electrophoresis, reversed-phase-HPLC and LC-MS. Under simulated gastric conditions, whey proteins in structured gels were hydrolysed faster than native proteins in solution. The rate of peptides released during in vitro digestion differed depending on the structure of the gels and extent of protein aggregation. The outcomes of this work highlighted that changes in the network structure of the protein can influence the rate and pattern of its proteolysis under gastrointestinal conditions. Such knowledge could assist the food industry in designing novel food formulations to control the digestion kinetics and the release of biologically active peptides for desired health outcome.

On the possibility of connecting a non-operating main circulation pump with three pumps in operation without preliminary coast-down of power-generating unit No. 5 in the Novovoronezh nuclear power plant

NASA Astrophysics Data System (ADS)

Vitkovskii, I. L.; Nikonov, S. P.; Ryasnyi, S. I.

2014-02-01

The subject of this paper is a transient caused by connection of a standby loop to three operating circulation pumps at the initial reactor heat rate equal to 70% of the rated value without preliminarily reducing it to 30% of the rated level as required by the safe operation regulations. Failure of the following normal operation systems is supposed: the first- and the second-type warning protection systems, all quick-acting reducing devices releasing steam into the auxiliary manifold, the electric heaters of the pressurizer, the pressurizer injection system, the primary cooling circuit fluid makeup/blow-through systems, and the blocking systems to shut down the main circulation pump after the level in the steam generator is exceeded. In addition, it is supposed that, under transient conditions, the valves of the turbine regulation system will be in the position in which they were at the moment of the initial event until generation of the signal for positive closing of the turbine stop valves. The first signal to actuate the reactor emergency protection system (EPS) is skipped. The failure of all quick-acting reducing devices releasing steam into the atmosphere is assumed. In addition to equipment failure, at the moment when the main circulation pump is connected, the operator erroneously puts in a new setting to maintain the power allowable for four pumps in operation-in the calculations it was taken equal to 104% of the rated level at most considering the accuracy of evaluating and maintaining the reactor heat rate-and the working group of the reactor protection and control system (P&CS) starts moving upward. On reaching the set power level, the automatic reactor power regulator stops operating and the P&CS elements remain in the position in which they are at the moment. Compliance with the design safety criteria for the adopted scenario of the transient is demonstrated.

Determining drug release rates of hydrophobic compounds from nanocarriers

PubMed Central

D’Addio, Suzanne M.; Bukari, Abdallah A.; Dawoud, Mohammed; Bunjes, Heike; Rinaldi, Carlos; Prud’homme, Robert K.

2016-01-01

Obtaining meaningful drug release profiles for drug formulations is essential prior to in vivo testing and for ensuring consistent quality. The release kinetics of hydrophobic drugs from nanocarriers (NCs) are not well understood because the standard protocols for maintaining sink conditions and sampling are not valid owing to mass transfer and solubility limitations. In this work, a new in vitroassay protocol based on ‘lipid sinks’ and magnetic separation produces release conditions that mimic the concentrations of lipid membranes and lipoproteins in vivo, facilitates separation, and thus allows determination of intrinsic release rates of drugs from NCs. The assay protocol is validated by (i) determining the magnetic separation efficiency, (ii) demonstrating that sink condition requirements are met, and (iii) accounting for drug by completing a mass balance. NCs of itraconazole and cyclosporine A (CsA) were prepared and the drug release profiles were determined. This release protocol has been used to compare the drug release from a polymer stabilized NC of CsA to a solid drug NP of CsA alone. These data have led to the finding that stabilizing block copolymer layers have a retarding effect on drug release from NCs, reducing the rate of CsA release fourfold compared with the nanoparticle without a polymer coating. This article is part of the themed issue ‘Soft interfacial materials: from fundamentals to formulation’. PMID:27298440

Determining drug release rates of hydrophobic compounds from nanocarriers.

PubMed

D'Addio, Suzanne M; Bukari, Abdallah A; Dawoud, Mohammed; Bunjes, Heike; Rinaldi, Carlos; Prud'homme, Robert K

2016-07-28

Obtaining meaningful drug release profiles for drug formulations is essential prior to in vivo testing and for ensuring consistent quality. The release kinetics of hydrophobic drugs from nanocarriers (NCs) are not well understood because the standard protocols for maintaining sink conditions and sampling are not valid owing to mass transfer and solubility limitations. In this work, a new in vitroassay protocol based on 'lipid sinks' and magnetic separation produces release conditions that mimic the concentrations of lipid membranes and lipoproteins in vivo, facilitates separation, and thus allows determination of intrinsic release rates of drugs from NCs. The assay protocol is validated by (i) determining the magnetic separation efficiency, (ii) demonstrating that sink condition requirements are met, and (iii) accounting for drug by completing a mass balance. NCs of itraconazole and cyclosporine A (CsA) were prepared and the drug release profiles were determined. This release protocol has been used to compare the drug release from a polymer stabilized NC of CsA to a solid drug NP of CsA alone. These data have led to the finding that stabilizing block copolymer layers have a retarding effect on drug release from NCs, reducing the rate of CsA release fourfold compared with the nanoparticle without a polymer coating.This article is part of the themed issue 'Soft interfacial materials: from fundamentals to formulation'. © 2016 The Author(s).

Heat release from wood wall assemblies using oxygen consumption method

Treesearch

Hao C. Tran; Robert E. White

1990-01-01

The concept of heat release rate is gaining acceptance in the evaluation of fire performance of materials and assemblies. However, this concept has not been incorporated into fire endurance testing such as the ASTM E-119 test method. Heat release rate of assemblies can be useful in determining the time at which the assemblies start to contribute to the controlled fire...

Role of construction debris in release of copper, chromium, and arsenic from treated wood structures

Treesearch

Stan T. Lebow; Steven A. Halverson; Jeffrey J. Morrell; John Simonsen

Recent research on the release of wood preservatives from treated wood used in sensitive environments has not considered the potential contribution from construction residues. This study sought to develop leaching rate data for small construction debris and compare those to the release rate from treated wood itself. Western hemlock boards were pressure treated with...

Application of a Smart Parachute Release Algorithm to the CPAS Test Architecture

NASA Technical Reports Server (NTRS)

Bledsoe, Kristin

2013-01-01

One of the primary test vehicles for the Capsule Parachute Assembly System (CPAS) is the Parachute Test Vehicle (PTV), a capsule shaped structure similar to the Orion design but truncated to fit in the cargo area of a C-17 aircraft. The PTV has a full Orion-like parachute compartment and similar aerodynamics; however, because of the single point attachment of the CPAS parachutes and the lack of Orion-like Reaction Control System (RCS), the PTV has the potential to reach significant body rates. High body rates at the time of the Drogue release may cause the PTV to flip while the parachutes deploy, which may result in the severing of the Pilot or Main risers. In order to prevent high rates at the time of Drogue release, a "smart release" algorithm was implemented in the PTV avionics system. This algorithm, which was developed for the Orion Flight system, triggers the Drogue parachute release when the body rates are near a minimum. This paper discusses the development and testing of the smart release algorithm; its implementation in the PTV avionics and the pretest simulation; and the results of its use on two CPAS tests.

All-Cause and External Mortality in Released Prisoners: Systematic Review and Meta-Analysis

PubMed Central

Zlodre, Jakov

2012-01-01

Objectives. We systematically reviewed studies of mortality following release from prison and examined possible demographic and methodological factors associated with variation in mortality rates. Methods. We searched 5 computer-based literature indexes to conduct a systematic review of studies that reported all-cause, drug-related, suicide, and homicide deaths of released prisoners. We extracted and meta-analyzed crude death rates and standardized mortality ratios by age, gender, and race/ethnicity, where reported. Results. Eighteen cohorts met review criteria reporting 26 163 deaths with substantial heterogeneity in rates. The all-cause crude death rates ranged from 720 to 2054 per 100 000 person-years. Male all-cause standardized mortality ratios ranged from 1.0 to 9.4 and female standardized mortality ratios from 2.6 to 41.3. There were higher standardized mortality ratios in White, female, and younger prisoners. Conclusions. Released prisoners are at increased risk for death following release from prison, particularly in the early period. Aftercare planning for released prisoners could potentially have a large public health impact, and further work is needed to determine whether certain groups should be targeted as part of strategies to reduce mortality. PMID:23078476

Behavioral aspects of Lutzomyia longipalpis (Diptera: Psychodidae) in urban area endemic for visceral leishmaniasis.

PubMed

De Oliveira, E F; Silva, E A; Casaril, A E; Fernandes, C E S; Paranhos Filho, A C; Gamarra, R M; Ribeiro, A A; Brazil, R P; Oliveira, A G

2013-03-01

The study of some of the behavioral aspects of the main vector of Leishmania infantum chagasi Cunha & Chagas in the Americas, Lutzomyia longipalpis (Lutz & Neiva), such as dispersion, population size, and vector survival rates, is important for the elucidation of the mechanisms of visceral leishmaniasis transmission. These parameters were studied by means of capture-mark-release-recapture experiments in an urban area of Campo Grande municipality, an endemic area of visceral leishmaniasis, situated in Mato Grosso do Sul state, Brazil. Six capture-mark-release-recapture experiments were undertaken between November 2009 and November 2010 and once in January 2012 with a view to assessing the population size and survival rate of Lu. longipalpis. The insects were released in a peridomicile surrounded by 13 residences. The recaptures were undertaken with automatic light traps for four consecutive weeks after release in the surrounding area. In total, 3,354 sand flies were captured, marked, and released. The overall recapture rate during the capture-mark-release-recapture experiments was 4.23%, of which 92.45% were recaptured at the release site, indicating limited dispersal. The greatest distance recorded from the release site was 165 m for males and 241 m for females. The male daily survival rate, calculated on the basis of regressions from the numbers of marked recaptured insects during the 15 successive days after release was 0.897. The estimated male population size measured by the Lincoln Index was 10,947.127. Though Lu. longipalpis presented a limited dispersion the physical barriers typical of urban environments did not prevent the sand flies from flying long distances.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kicker, Dwayne Curtis; Herrick, Courtney G; Zeitler, Todd

The numerical code DRSPALL (from direct release spallings) is written to calculate the volume of Waste Isolation Pilot Plant solid waste subject to material failure and transport to the surface (i.e., spallings) as a result of a hypothetical future inadvertent drilling intrusion into the repository. An error in the implementation of the DRSPALL finite difference equations was discovered and documented in a software problem report in accordance with the quality assurance procedure for software requirements. This paper describes the corrections to DRSPALL and documents the impact of the new spallings data from the modified DRSPALL on previous performance assessment calculations.more » Updated performance assessments result in more simulations with spallings, which generally translates to an increase in spallings releases to the accessible environment. Total normalized radionuclide releases using the modified DRSPALL data were determined by forming the summation of releases across each potential release pathway, namely borehole cuttings and cavings releases, spallings releases, direct brine releases, and transport releases. Because spallings releases are not a major contributor to the total releases, the updated performance assessment calculations of overall mean complementary cumulative distribution functions for total releases are virtually unchanged. Therefore, the corrections to the spallings volume calculation did not impact Waste Isolation Pilot Plant performance assessment calculation results.« less

Recharge of the early atmosphere of Mars by impact-induced release of CO2

NASA Technical Reports Server (NTRS)

Carr, Michael H.

1989-01-01

The question as to whether high impact rates early in the history of Mars could have aided in maintaining a relatively thick CO2 atmosphere is discussed. Such impacts could have released CO2 into the atmosphere by burial, by shock-induced release during impact events, and by the addition of carbon to Mars from the impacting bolides. On the assumption that cratering rates on Mars were comparable to those of the moon's Nectarial period, burial rates are a result of 'impact gardening' at the end of heavy bombardment are estimated to have ranged from 20 to 45 m/million years; at these rates, 0.1-0.2 bar of CO2 would have been released every 10 million years as a result of burial to depths at which carbonate dissociation temperatures are encountered.

Effect of Mg2+ on the control of Ca2+ release in skeletal muscle fibres of the toad.

PubMed Central

Lamb, G D; Stephenson, D G

1991-01-01

1. The effect of myoplasmic Mg2+ on Ca2+ release was examined in mechanically skinned skeletal muscle fibres, in which the normal voltage-sensor control of Ca2+ release is preserved. The voltage sensors could be activated by depolarizing the transverse tubular (T-) system by lowering the [K+] in the bathing solution. 2. Fibres spontaneously contracted when the free [Mg2+] was decreased from 1 to 0.05 mM, with no depolarization or change of total ATP, [Ca2+] or pH (pCa 6.7, 50 microM-EGTA). After such a 'low-Mg2+ response' the sarcoplasmic reticulum (SR) was depleted of Ca2+ and neither depolarization nor caffeine (2 mM) could induce a response, unless the [Mg2+] was raised and the SR reloaded with Ca2+. Exposure to 0.05 mM-Mg2+ at low [Ca2+] (2 mM-free EGTA, pCa greater than 8.7) also induced Ca2+ release and depleted the SR. 3. The response to low [Mg2+] was unaffected by inactivation of the voltage sensors, but was completely blocked by 2 microM-Ruthenium Red indicating that it involved Ca2+ efflux through the normal Ca2+ release channels. 4. In the absence of ATP (and creatine phosphate), complete removal of Mg2+ (i.e. no added Mg2+ with 1 mM-EDTA) did not induce Ca2+ release. Depolarization in the absence of Mg2+ and ATP also did not induce Ca2+ release. 5. Depolarization in 10 mM-Mg2+ (pCa 6.7, 50 microM-EGTA, 8 mM-total ATP) did not produce any response. In the presence of 1 mM-EGTA to chelate most of the released Ca2+, depolarizations in 10 mM-Mg2+ did not noticeably deplete the SR of Ca2+, whereas a single depolarization in 1 mM-Mg2+ (and 1 mM-EGTA) resulted in marked depletion. Depolarization in the presence of D600 and 10 mM-Mg2+ produced use-dependent 'paralysis', indicating that depolarization in 10 mM-Mg2+ did indeed activate the voltage sensors. 6. Depolarization in the presence of 10 mM-Mg2+ and 25 microM-ryanodine neither interfered with the normal voltage control of Ca2+ release nor caused depletion of the Ca2+ in the SR even after returning to 1 mM-Mg2+ for 1 min, indicating that few if any of the release channels had been opened by the depolarization.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:1708823

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lombardo, N.J.; Marseille, T.J.; White, M.D.

TRUMP-BD (Boil Down) is an extension of the TRUMP (Edwards 1972) computer program for the analysis of nuclear fuel assemblies under severe accident conditions. This extension allows prediction of the heat transfer rates, metal-water oxidation rates, fission product release rates, steam generation and consumption rates, and temperature distributions for nuclear fuel assemblies under core uncovery conditions. The heat transfer processes include conduction in solid structures, convection across fluid-solid boundaries, and radiation between interacting surfaces. Metal-water reaction kinetics are modeled with empirical relationships to predict the oxidation rates of steam-exposed Zircaloy and uranium metal. The metal-water oxidation models are parabolic inmore » form with an Arrhenius temperature dependence. Uranium oxidation begins when fuel cladding failure occurs; Zircaloy oxidation occurs continuously at temperatures above 13000{degree}F when metal and steam are available. From the metal-water reactions, the hydrogen generation rate, total hydrogen release, and temporal and spatial distribution of oxide formations are computed. Consumption of steam from the oxidation reactions and the effect of hydrogen on the coolant properties is modeled for independent coolant flow channels. Fission product release from exposed uranium metal Zircaloy-clad fuel is modeled using empirical time and temperature relationships that consider the release to be subject to oxidation and volitization/diffusion ( bake-out'') release mechanisms. Release of the volatile species of iodine (I), tellurium (Te), cesium (Ce), ruthenium (Ru), strontium (Sr), zirconium (Zr), cerium (Cr), and barium (Ba) from uranium metal fuel may be modeled.« less

Development and characterization of different black raspberry confection matrices designed for delivery of phytochemicals.

PubMed

Gu, Junnan; Ahn-Jarvis, Jennifer H; Vodovotz, Yael

2015-03-01

Three forms of confections containing black raspberries (BRB) powder were developed to provide controlled release of phytochemicals for oral disease prevention. Our objective was to investigate the impact of varying confection matrices on the release rate of BRB phytochemicals. Confections were developed and prepared. Textural properties of confections were analyzed, compared and correlated with the release rate of phytochemicals from BRB confections with in vitro dissolution test. In the results, BRB content reached 22% in hard candy and pectin-based confections and 40% in starch-based confections, respectively. Pectin- and starch-based confections retained >93% of its original anthocyanins after processing while hard candy had 59%. Starch confections showed higher G' in rheological analysis and higher hardness but lower cohesiveness and springiness in textural profile analysis than pectin confections (P < 0.05). The confection types showed different microstructure with scanning electronic microscopy (SEM). Corresponding to their physicochemical properties, confections showed fast (hard candy), intermediate (pectin confections), and slow (starch confections) release rates with a final releasing time of 90, 150, and 540 min in dissolution studies. Three confections were rated between neither like nor dislike to like slightly (n = 60). Pectin confections had the highest overall acceptance (like slightly) and 62% of subjects rated this type of confection as the most liked ones. These results indicate that delivery matrix could modulate the phytochemical release rate from BRB confection and also influence sensory preference. © 2015 Institute of Food Technologists®

Non-Toxic, Self Cleaning Silicone Fouling Release Coatings

DTIC Science & Technology

1997-10-07

Attempts to microencapsulate silicone oils for enhanced fouling release coatings with thermoset wall structures were unsuccessful: Microcapsule ...filled coatings failed abrasion resistance tests and had mediocre fouling release properties, despite having controlled release rates. Microcapsules with

Analysis of interlaminar stresses in thick composite laminates with and without edge delamination

NASA Technical Reports Server (NTRS)

Whitcomb, J. D.; Raju, I. S.

1984-01-01

The effect of laminate thickness on the interlaminar stresses in rectangular quasi-isotropic laminates under uniform axial strain was studied. Laminates from 8-ply to infinitely thick were analyzed. Thick laminates were synthesized by stacking (45/0/-45/90) ply groups, rather than grouping like plies. Laminates with and without delaminations were studied. In laminates without delaminations, the free-edge interlaminar normal stress distribution in the outer ply groups was insensitive to total laminate thickness. The interlaminar normal stress distribution for the interior ply groups was nearly the same as for an infinitely thick laminate. In contrast, the free-edge inter-laminar shear stress distribution was nearly the same for inner and outer ply groups and was insensitive to laminate thickness. In laminates with delaminations those delaminations near the top and bottom surfaces of a thick laminate have much larger total strain-energy-release rates (G sub t) and mode I-to-total (G sub t/G sub t) ratios than delaminations deep in the interior. Therefore, delaminations can be expected to grow more easily near the surfaces of a laminate than in the interior.

Decay of a linear pendulum in a collisional gas: Spatially one-dimensional case

NASA Astrophysics Data System (ADS)

Tsuji, Tetsuro; Aoki, Kazuo

2014-05-01

An infinitely wide plate, subject to an external force in its normal direction obeying Hooke's law, is placed in an infinite expanse of a rarefied gas. When the plate is displaced from its equilibrium position and released, it starts in general an oscillatory motion in its normal direction. This is the one-dimensional setting of a linear pendulum considered previously for a collisionless gas and a special Lorentz gas by the present authors [T. Tsuji and K. Aoki, J. Stat. Phys. 146, 620 (2012), 10.1007/s10955-011-0412-7]. The motion decays as time proceeds because of the drag force on the plate exerted by the surrounding gas. The long-time behavior of the unsteady motion of the gas caused by the motion of the plate is investigated numerically on the basis of the Bhatnagar-Gross-Krook (BGK) model of the Boltzmann equation with special interest in the rate of the decay of the oscillatory motion of the plate. The result provides numerical evidence that the displacement of the plate decays in proportion to an inverse power of time for large time.

Decay of a linear pendulum in a collisional gas: spatially one-dimensional case.

PubMed

Tsuji, Tetsuro; Aoki, Kazuo

2014-05-01

An infinitely wide plate, subject to an external force in its normal direction obeying Hooke's law, is placed in an infinite expanse of a rarefied gas. When the plate is displaced from its equilibrium position and released, it starts in general an oscillatory motion in its normal direction. This is the one-dimensional setting of a linear pendulum considered previously for a collisionless gas and a special Lorentz gas by the present authors [T. Tsuji and K. Aoki, J. Stat. Phys. 146, 620 (2012)]. The motion decays as time proceeds because of the drag force on the plate exerted by the surrounding gas. The long-time behavior of the unsteady motion of the gas caused by the motion of the plate is investigated numerically on the basis of the Bhatnagar-Gross-Krook (BGK) model of the Boltzmann equation with special interest in the rate of the decay of the oscillatory motion of the plate. The result provides numerical evidence that the displacement of the plate decays in proportion to an inverse power of time for large time.

A Tunable, Biodegradable, Thin-Film Polymer Device as a Long-Acting Implant Delivering Tenofovir Alafenamide Fumarate for HIV Pre-exposure Prophylaxis

PubMed Central

Schlesinger, Erica; Johengen, Daniel; Luecke, Ellen; Rothrock, Ginger; McGowan, Ian; van der Straten, Ariane; Desai, Tejal

2016-01-01

Purpose The effectiveness of Tenofovir based HIV pre-exposure prophylaxis (PrEP) is proven, but hinges on correct and consistent use. User compliance and therapeutic effectiveness can be improved by long acting drug delivery systems. Here we describe a thin-film polymer device (TFPD) as a biodegradable subcutaneous implant for PrEP. Methods A thin-film polycaprolactone (PCL) membrane controls drug release from a reservoir. To achieve membrane controlled release, TAF requires a formulation excipient such as PEG300 to increase the dissolution rate and reservoir solubility. Short-term In vitro release studies are used to develop an empirical design model, which is applied to the production of in vitro prototype devices demonstrating up to 90-days of linear release and TAF chemical stability. Results The size and shape of the TFPD are tunable, achieving release rates ranging from 0.5–4.4 mg/day in devices no larger than a contraceptive implant. Based on published data for oral TAF, subcutaneous constant-rate release for HIV PrEP is estimated at < 2.8mg/day. Prototype devices demonstrated linear release at 1.2mg/day for up to 90 days and at 2.2mg/day for up to 60 days. Conclusions We present a biodegradable TFPD for subcutaneous delivery of TAF for HIV PrEP. The size, shape and release rate of the device are tunable over a > 8-fold range. PMID:26975357

[Effects of nitrogen application rates and straw returning on nutrient balance and grain yield of late sowing wheat in rice-wheat rotation].

PubMed

Zhang, Shan; Shi, Zu-liang; Yang, Si-jun; Gu, Ke-jun; Dai, Ting-bo; Wang, Fei; Li, Xiang; Sun, Ren-hua

2015-09-01

Field experiments were conducted to study the effects of nitrogen application rates and straw returning on grain yield, nutrient accumulation, nutrient release from straw and nutrient balance in late sowing wheat. The results showed that straw returning together with appropriate application of nitrogen fertilizer improved the grain yield. Dry matter, nitrogen, phosphorus and potassium accumulation increased significantly as the nitrogen application rate increased. At the same nitrogen application rate (270 kg N · hm(-2)), the dry matter, phosphorus and potassium accumulation of the treatment with straw returning were higher than that without straw returning, but the nitrogen accumulation was lower. Higher-rate nitrogen application promoted straw decomposition and nutrient release, and decreased the proportion of the nutrient released from straw after jointing. The dry matter, phosphorus and potassium release from straw showed a reverse 'N' type change with the wheat growing, while nitrogen release showed a 'V' type change. The nutrient surplus increased significantly with the nitrogen application rate. At the nitrogen application rate for the highest grain yield, nitrogen and potassium were surplus significantly, and phosphorus input could keep balance. It could be concluded that as to late sowing wheat with straw returning, applying nitrogen at 257 kg · hm(-2) and reducing potassium fertilizer application could improve grain yield and reduce nutrients loss.

Phosphorus mobilization from littoral sediments of an inlet region in Lake Delavan, Wisconsin

USGS Publications Warehouse

James, W.F.; Barko, J.W.; Field, S.J.

1996-01-01

Rates of P release from littoral sediments of the inlet region of Lake Delavan, Wisconsin, were examined in the laboratory under different redox and pH regimes using sediment systems and also in situ using sediment peppers. In the laboratory, rates of P release from sediments increased about two-fold (i.e., to 7 mg m-2 d-1) under oxic conditions as a result of adjusting the pH of the overlying water from 8.5 to about 9.0. Laboratory rates increased to a maximum of 23 mg m-2 d-1 under anoxic conditions. Both in situ pH and dissolved oxygen (DO) exhibited marked seasonal fluctuations due, primarily, to metabolism by submersed macrophytes, which occupied over 50% of the inlet region. Using continuous records of in situ pH and DO and ranges in rates of P release measured in the laboratory, we estimated an overall mean rate of P release of 5.7 mg m-2 d-1 from the littoral sediments during the summer (April-September) of 1994. Rates of P release estimated from Fickean diffusional fluxes were similar to rates estimated from pH and DO. Our results suggest that aquatic macrophyte communities of the inlet region enhance the mobilization of P from littoral sediment by regulating pH and DO in the surrounding environment.

Assessment of survival rates and reproductive success of captive bred milky stork released at Kuala Gula Bird Sanctuary, Perak

NASA Astrophysics Data System (ADS)

Faiq, H.; Safie, M. Y.; Shukor, M. N.

2016-11-01

A release programme of captive bred Milky Storks was initiated to increase population size in the wild. Population size depends on the survival rate and breeding success of individuals in the population. Among factors that affect survival rate and breeding success are population age class and sex ratio. The main objective of this study was to estimate the survival rate of Mycteria cinerea that has been released in Kuala Gula Bird Sanctuary since 2007. The estimation of the survival rate was done across gender and age class. This study was conducted in 2012 at Kuala Gula Bird Sanctuary. The presence of M. cinerea individuals were recorded at the sanctuary and identified to background information, such as date of birth, gender and date of release. Females of M. cinerea were estimated to have a higher survival rate (30.0%) than male (16.7%). Across gender, each individual was assigned into 4 different age classes, namely less than 1 year, between 1 and 2 years, between 2 and 3 years, and more than 3 years. The survival rate of individuals less than 1 year was about 50%, between 1 and 2 years was 25%, between 2 and 3 years was 9.1%, and more than 3 years was 0%. This study was intended to facilitate future release programmeme on which gender and age class to emphasize.

Short-term Outcomes following Concussion in the NFL: An 11-year Retrospective Study of Player Release Rate and Financial Loss

PubMed Central

Ramkumar, Prem; Navarro, Sergio Michael

2017-01-01

Objectives: The primary goal of this study was to assess the short-term outcomes among National Football League (NFL) players following concussion in terms of: (1) DNP protocol activation, (2) release rate at one and three years, and (3) mean salary reduction. A secondary goal of the study was to stratify the post-concussive release rate by franchise and player position. Methods: NFL player transaction records and publicly available weekly injury reports from August 2005 to January 2016 for NFL players were analyzed. All players immediately sustaining recorded concussions were evaluated for a change to inactive or do-not-play (DNP) status. The one-year and three-year release rate following concussion was defined as any player transitioning to inactivation, retirement, free agency, or any failure to return for a successive season on the same team’s active roster after one or three years from the initial concussion. Student’s t-test was used to compare release rates between non-concussed and concussed players at one and three years. Mean salary reduction per year following concussion was calculated using publicly available player contracts. Additionally, franchise-level and position-based analyses of the release rate were performed. Results: Of the total 5,451 NFL players retrospectively analyzed over the 11-year period, 373 sustained publicly reported concussions resulting in DNP protocol activation. The release rate of the post-concussive versus non-concussive player was 26% vs. 20% at 1 year (p<0.01) and 31% vs. 19% at 3 years (p<0.01). After analyzing individual player contracts, the mean year-over-year change in contract value for concussed players after DNP protocol activation was an overall salary reduction of $760,000/year ± $2,380,000. Figure 1 depicts the tendency of each NFL franchise to release an athlete following concussion within one and three years. Table 1 reports a position-based analysis in terms of concussion rate, mean salary reduction, and NFL career longevity. Conclusion: Our retrospective study demonstrates that NFL concussions resulting in DNP protocol activation leads to a statistically greater release rate among concussed NFL players than non-concussed players. Released players suffered reduction in year-over-year accumulated earnings, and particular franchises tended to release concussed players more than others. Position-based Concussion Statistics of Players by DNP Activation, Salary Reduction, Career LengthPosition GroupDNP ConcussionsMean Salary Reduction ($/yr)Average Career Length (yrs)DB75 (20.1%)280,0007.0WR66 (17.7%)1,760,0007.3OL49 (13.1%)1,190,0005.5TE46 (12.3%)333,0007.7RB40 (10.7%)140,0005.1LB39 (10.5%)720,0004.9DL31 (8.3%)540,0007.0QB27 (7.2%)2,440,0007.3Total373760,0006.4

Investigation of the effect of hydroxypropyl methylcellulose on the phase transformation and release profiles of carbamazepine-nicotinamide cocrystal.

PubMed

Li, Mingzhong; Qiu, Shi; Lu, Yan; Wang, Ke; Lai, Xiaojun; Rehan, Mohammad

2014-09-01

The aim of this work was to investigate the influence of hydroxypropyl methylcellulose (HPMC) on the phase transformation and release profile of carbamazepine-nicotinamide (CBZ-NIC) cocrystal in solution and in sustained release matrix tablets. The polymorphic transitions of the CBZ-NIC cocrystal and its crystalline properties were examined by differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), Raman spectroscopy, and scanning electron microscopy (SEM). The apparent CBZ solubility and dissolution rate of CBZ-NIC cocrystal were constant in different concentrations of HPMC solutions. In a lower percentage of HPMC in the matrix tablets, the CBZ release profile of the CBZ-NIC cocrystal was nonlinear and declined over time. With an increased HPMC content in the tablets, the CBZ-NIC cocrystal formulation showed a significantly higher CBZ release rate in comparison with the other two formulations of CBZ III and the physical mixture. Because of a significantly improved dissolution rate of the CBZ-NIC cocrystal, the rate of CBZ entering into solution is significantly faster than the rate of formation of the CBZ-HPMC soluble complex in solution, leading to a higher supersaturation level of CBZ and subsequently precipitation of CBZ dihydrate.

Observed Barium Emission Rates

NASA Technical Reports Server (NTRS)

Stenbaek-Nielsen, H. C.; Wescott, E. M.; Hallinan, T. J.

1993-01-01

The barium releases from the CRRES satellite have provided an opportunity for verifying theoretically calculated barium ion and neutral emission rates. Spectra of the five Caribbean releases in the summer of 1991 were taken with a spectrograph on board a U.S. Air Force jet aircraft. Because the line of sight release densities are not known, only relative rates could be obtained. The observed relative rates agree well with the theoretically calculated rates and, together with other observations, confirm the earlier detailed theoretical emission rates. The calculated emission rates can thus with good accuracy be used with photometric observations. It has been postulated that charge exchange between neutral barium and oxygen ions represents a significant source for ionization. If so. it should be associated with emissions at 4957.15 A and 5013.00 A, but these emissions were not detected.

Evaluation of rate of swelling and erosion of verapamil (VRP) sustained-release matrix tablets.

PubMed

Khamanga, Sandile M; Walker, Roderick B

2006-01-01

Tablets manufactured in-house were compared to a marketed sustained-release product of verapamil to investigate the rate of hydration, erosion, and drug-release mechanism by measuring the wet and subsequent dry weights of the products. Swelling and erosion rates depended on the polymer and granulating fluid used, which ultimately pointed to their permeability characteristics. Erosion rate of the marketed product was highest, which suggests that the gel layer that formed around these tablets was weak as opposed to the robust and resistant layers of test products. Anomalous and near zero-order transport mechanisms were dominant in tests and commercial product, respectively.

Transition States and transition state analogue interactions with enzymes.

PubMed

Schramm, Vern L

2015-04-21

Enzymatic transition states have lifetimes of a few femtoseconds (fs). Computational analysis of enzyme motions leading to transition state formation suggests that local catalytic site motions on the fs time scale provide the mechanism to locate transition states. An experimental test of protein fs motion and its relation to transition state formation can be provided by isotopically heavy proteins. Heavy enzymes have predictable mass-altered bond vibration states without altered electrostatic properties, according to the Born-Oppenheimer approximation. On-enzyme chemistry is slowed in most heavy proteins, consistent with altered protein bond frequencies slowing the search for the transition state. In other heavy enzymes, structural changes involved in reactant binding and release are also influenced. Slow protein motions associated with substrate binding and catalytic site preorganization are essential to allow the subsequent fs motions to locate the transition state and to facilitate the efficient release of products. In the catalytically competent geometry, local groups move in stochastic atomic motion on the fs time scale, within transition state-accessible conformations created by slower protein motions. The fs time scale for the transition state motions does not permit thermodynamic equilibrium between the transition state and stable enzyme states. Isotopically heavy enzymes provide a diagnostic tool for fast coupled protein motions to transition state formation and mass-dependent conformational changes. The binding of transition state analogue inhibitors is the opposite in catalytic time scale to formation of the transition state but is related by similar geometries of the enzyme-transition state and enzyme-inhibitor interactions. While enzymatic transition states have lifetimes as short as 10(-15) s, transition state analogues can bind tightly to enzymes with release rates greater than 10(3) s. Tight-binding transition state analogues stabilize the rare but evolved enzymatic geometry to form the transition state. Evolution to efficient catalysis optimized this geometry and its stabilization by a transition state mimic results in tight binding. Release rates of transition state analogues are orders of magnitude slower than product release in normal catalytic function. During catalysis, product release is facilitated by altered chemistry. Compared to the weak associations found in Michaelis complexes, transition state analogues involve strong interactions related to those in the transition state. Optimum binding of transition state analogues occurs when the complex retains the system motions intrinsic to transition state formation. Conserved dynamic motion retains the entropic components of inhibitor complexes, improving the thermodynamics of analogue binding.

Joint release rate estimation and measurement-by-measurement model correction for atmospheric radionuclide emission in nuclear accidents: An application to wind tunnel experiments.

PubMed

Li, Xinpeng; Li, Hong; Liu, Yun; Xiong, Wei; Fang, Sheng

2018-03-05

The release rate of atmospheric radionuclide emissions is a critical factor in the emergency response to nuclear accidents. However, there are unavoidable biases in radionuclide transport models, leading to inaccurate estimates. In this study, a method that simultaneously corrects these biases and estimates the release rate is developed. Our approach provides a more complete measurement-by-measurement correction of the biases with a coefficient matrix that considers both deterministic and stochastic deviations. This matrix and the release rate are jointly solved by the alternating minimization algorithm. The proposed method is generic because it does not rely on specific features of transport models or scenarios. It is validated against wind tunnel experiments that simulate accidental releases in a heterogonous and densely built nuclear power plant site. The sensitivities to the position, number, and quality of measurements and extendibility of the method are also investigated. The results demonstrate that this method effectively corrects the model biases, and therefore outperforms Tikhonov's method in both release rate estimation and model prediction. The proposed approach is robust to uncertainties and extendible with various center estimators, thus providing a flexible framework for robust source inversion in real accidents, even if large uncertainties exist in multiple factors. Copyright © 2017 Elsevier B.V. All rights reserved.

Speech Rate Normalization and Phonemic Boundary Perception in Cochlear-Implant Users

ERIC Educational Resources Information Center

Jaekel, Brittany N.; Newman, Rochelle S.; Goupell, Matthew J.

2017-01-01

Purpose: Normal-hearing (NH) listeners rate normalize, temporarily remapping phonemic category boundaries to account for a talker's speech rate. It is unknown if adults who use auditory prostheses called cochlear implants (CI) can rate normalize, as CIs transmit degraded speech signals to the auditory nerve. Ineffective adjustment to rate…

Neutrophil Kinetics in Acute Infection*

PubMed Central

Marsh, J. C.; Boggs, D. R.; Cartwright, G. E.; Wintrobe, M. M.

1967-01-01

Neutrophil kinetics of acute experimental infection were studied with diisopropylfluorophosphate-32P labeling in 31 dogs inoculated intrabronchially with pneumococci. In vitro neutrophil labeling indicated a rapid transit time through the blood in early infections, with an elevated marginal granulocyte pool sometimes preceding an elevation of the circulating granulocyte pool. 13 hr after infection, the circulating and total blood granulocyte pools were increased but the rate of neutrophil transit through the blood was normal. During the recovery from infection there was a marked prolongation of neutrophil blood transit time, suggesting virtually complete cessation of bone marrow release of neutrophils into the blood. Labeling of neutrophils in vivo indicated an increased rate of emptying of the bone marrow storage pool proportional to the severity of infection as measured by the fever index. The change in the blood ratio of nonsegmented to segmented neutrophils was a much more accurate index of the severity of infection than the blood granulocyte concentration, correlating significantly with the fever index. PMID:6073999

Plasma secretin, plasma cholecystokinin, pancreaticobiliary secretion, and fat absorption: effect of duodenal osmolality and polysorbate 80.

PubMed

Olsen, O; Schaffalitzky de Muckadell, O B; Cantor, P

1987-11-01

In 20 normal persons we investigated the effects of duodenal osmolality on the release of secretin and cholecystokinin (CCK), pancreaticobiliary secretion, and fat absorption after intestinal infusion of emulsified oleic acid (pH 6.0). The release of CCK was found to be unaffected by the changes in osmolality, whereas the plasma levels of secretin were affected in parallel with volume and bicarbonate secretion. An inverse relation was found between fatty acid absorption and release of secretin and bicarbonate secretion but not between fatty acid absorption and release of CCK. It is suggested that the secretin and CCK cells respond differently to emulsified oleic acid.

Launch Lock Assemblies with Reduced Preload and Spacecraft Isolation Systems Including the Same

NASA Technical Reports Server (NTRS)

Barber, Tim Daniel (Inventor); Young, Ken (Inventor); Hindle, Timothy (Inventor)

2016-01-01

Launch lock assemblies with reduced preload are provided. The launch lock assembly comprises first and second mount pieces, a releasable clamp device, and a pair of retracting assemblies. Each retracting assembly comprises a pair of toothed members having interacting toothed surfaces. The releasable clamp device normally maintains the first and second mount pieces in clamped engagement. When the releasable clamp device is actuated, the first and second mount pieces are released from clamped engagement and one toothed member of each retracting assembly moves in an opposite direction relative to the other one toothed member of the other retracting assembly to define an axial gap on each side of the first mount piece.

CPTAC Releases Cancer Proteome Confirmatory Colon Study Data | Office of Cancer Clinical Proteomics Research

Cancer.gov

The National Cancer Institute (NCI) Clinical Proteomic Tumor Analysis Consortium (CPTAC) announces the release of the cancer proteome confirmatory colon study data. The goal of the study is to analyze the proteomes of approximately 100 confirmatory colon tumor patients, which includes tumor and adjacent normal samples, with liquid chromatography-tandem mass spectrometry (LC-MS/MS) global proteomic and phosphoproteomic profiling.

FASTGRASS: A mechanistic model for the prediction of Xe, I, Cs, Te, Ba, and Sr release from nuclear fuel under normal and severe-accident conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rest, J.; Zawadzki, S.A.

The primary physical/chemical models that form the basis of the FASTGRASS mechanistic computer model for calculating fission-product release from nuclear fuel are described. Calculated results are compared with test data and the major mechanisms affecting the transport of fission products during steady-state and accident conditions are identified.

77 FR 26541 - Alabama Power Company; Notice of Application for Amendment of License Accepted for Filing and...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-04

... (cfs), beginning immediately after Commission approval until December 31, 2012. Under normal operation Alabama Power is required to release 2,000 cfs from Jordan Dam July 1 through March 31 and release a continuous base flow of 4,000 cfs for 18 hours/day and an 8,000 cfs pulse flow for 6 hours/ day from April 1...

Enhanced effect of gap junction uncouplers on macroscopic electrical properties of reperfused myocardium

PubMed Central

Rodriguez-Sinovas, Antonio; García-Dorado, David; Ruiz-Meana, Marisol; Soler-Soler, Jordi

2004-01-01

Transient inhibition of gap junction (GJ)-mediated communication with heptanol during myocardial reperfusion limits infarct size. However, inhibition of cell coupling in normal myocardium may be arrhythmogenic. The purpose of this study was to test the hypothesis that the consequences of GJ inhibition may be magnified in reperfused myocardium compared with normal tissue, thus allowing the inhibition of GJs in reperfused tissue while only minimally modifying overall macroscopic cell coupling in normal myocardium. Concentration–response curves were defined for the effects of heptanol, 18α-glycyrrhetinic acid, halothane, and palmitoleic acid on conduction velocity, tissue electrical impedance, developed tension and lactate dehydrogenase (LDH) release in normoxically perfused rat hearts (n = 17). Concentrations lacking significant effects on tissue impedance were added during the initial 15 min of reperfusion in hearts submitted to 60 min (n = 43) or 30 min (n = 35) of ischaemia. These concentrations markedly increased myocardial electrical impedance (resistivity and phase angle) in myocardium reperfused after either 30 or 60 min of ischaemia, and reduced reperfusion-induced LDH release after 1 h of ischaemia by 83.6, 57.9, 51.7 and 52.5% for heptanol, 18α-glycyrrhetinic acid, halothane and palmitoleic acid, respectively. LDH release was minimal in hearts submitted to 30 min of ischaemia, independently of group allocation. In conclusion, the present results strongly support the hypothesis that intercellular communication in postischaemic myocardium may be effectively reduced by concentrations of GJ inhibitors affecting only minimally overall electrical impedance in normal myocardium. Reduction of cell coupling during initial reperfusion was consistently associated with attenuated lethal reperfusion injury. PMID:15218064

Synthesis and Characterization of Chlorpyrifos/Copper(II) Schiff Base Mesoporous Silica with pH Sensitivity for Pesticide Sustained Release.

PubMed

Chen, Huayao; Lin, Yueshun; Zhou, Hongjun; Zhou, Xinhua; Gong, Sheng; Xu, Hua

2016-11-02

The salicylaldehyde-modified mesoporous silica (SA-MCM-41) was prepared through a co-condensation method. Through the bridge effect from the copper ion, which also acts as the nutrition of the plant, the model drug chlorpyrifos (CH) was supported on the copper(II) Schiff base mesoporous silica (Cu-MCM-41) to form a highly efficient sustained-release system (CH-Cu-MCM-41) for pesticide delivery. The experimental results showed that the larger the concentration of the copper ion, the more adsorption capacity (AC) of Cu-MCM-41 for chlorpyrifos and the smaller its release rate. The results confirmed the existence of a coordination bond between SA-MCM-41 and copper ions as well as a coordination bond between Cu-MCM-41 and chlorpyrifos. The AC of SA-MCM-41 is 106 mg/g, while that of Cu-MCM-41 is 295 mg/g. The as-synthesized system showed significant pH sensitivity. Under the condition of pH ≤ 7, the release rate of chlorpyrifos decreased with increasing pH, whereas its release rate in weak base conditions was slightly larger than that in weak acid conditions. Meanwhile, the drug release rate of the as-synthesized system was also affected by the temperature. Their sustained-release curves can be described by the Korsmeyer-Peppas equation.

Development of a Method to Measure Organotin Release Rates

DTIC Science & Technology

1989-12-01

tributyltin per liter Pm Micrometers mm Millimeters NOSC Naval Ocean Systems Center RCW Relative confidence width TBT Tributyltin TBTCl Tributyltin ...organotin paint research is to develop a coating which controls fouling effec- tively with a minimum release of tributyltin ( TBT ). In addition to...DTNSRDC) are conducting a series of experiments in order to determine the tributyltin ( TBT ) release rates of various organotin antifouling paints. The

Effect of hypothyroidism on the hypothalamic-pituitary-ovarian axis and reproductive function of pregnant rats.

PubMed

Sun, Jianran; Hui, Cancan; Xia, Tongjia; Xu, Min; Deng, Datong; Pan, Faming; Wang, Youmin

2018-05-24

This study aimed to detect changes in hormone levels in the hypothalamic-pituitary-ovarian axis in Sprague-Dawley (SD) rats with hypothyroidism, and identify differences in the pregnancy and abortion rates of female adult rats. The potential role of gonadotropin releasing hormone (GnRH) as the link between the hypothalamic-pituitary-ovarian axis and reproductive function regulated by thyroid hormones was also investigated. Female SD rats (n = 136) were causally classified into two groups: the normal-drinking-water group (n = 60) and the 0.05% propylthiouracil-drinking-water group (PTU 2 mg/kg/day, n = 76) to establish an adult rat model of hypothyroidism (6 weeks). Female and male rats at a ratio of 1:2 were used to establish a hypothyroidism pregnancy model. GnRH mRNA and GnRH receptor (GnRHR) expression in rats was detected using real time quantitative PCR(qRT-PCR) and immunohistochemistry, respectively. The abortion rate differed significantly between the hypothyroidism pregnancy group and the normal pregnancy group (P < 0.05). No significant differences were found in the distribution of the GnRHR among the five nuclei (hypothalamic arcuate nucleus, hypothalamic ventromedial nucleus, hypothalamic anterior nucleus, paraventricular nucleus of the hypothalamus, and ventral premammillary nucleus) of the hypothalamus and ovary (P > 0.05). Hypothyroidism had no significant effect on GnRH mRNA expression in the hypothalamic-pituitary-ovarian axis in the four groups (normal control group, normal pregnancy group, hypothyroidism pregnancy group, and hypothyroidism group) (P > 0.05). Hypothyroidism had an adverse impact on pregnancy in rats and may affect the distribution of pituitary GnRHR, whereas it did not obviously affect the distribution of GnRHR in the nuclei of the hypothalamus and ovary. Hypothyroidism had no effect on GnRH mRNA expression.

[Effects of carbon sources, temperature and electron acceptors on biological phosphorus removal].

PubMed

Han, Yun; Xu, Song; Dong, Tao; Wang, Bin-Fan; Wang, Xian-Yao; Peng, Dang-Cong

2015-02-01

Effects of carbon sources, temperature and electron acceptors on phosphorus uptake and release were investigated in a pilot-scale oxidation ditch. Phosphorus uptake and release rates were measured with different carbon sources (domestic sewage, sodium acetate, glucose) at 25 degrees C. The results showed that the minimum phosphorus uptake and release rates of glucose were 5.12 mg x (g x h)(-1) and 6.43 mg x (g x h)(-1), respectively, and those of domestic sewage are similar to those of sodium acetate. Phosphorus uptake and release rates increased with the increase of temperature (12, 16, 20 and 25 degrees C) using sodium acetate as carbon sources. Anoxic phosphorus uptake rate decreased with added COD. Electron acceptors (oxygen, nitrate, nitrite) had significant effects on phosphorus uptake rate and their order was in accordance with oxygen > nitrate > nitrite. The mass ratio of anoxic P uptake and N consumption (P(uptake)/N (consumption)) of nitrate and nitrite were 0.96 and 0.65, respectively.

Nanopore thin film enabled optical platform for drug loading and release.

PubMed

Song, Chao; Che, Xiangchen; Que, Long

2017-08-07

In this paper, a drug loading and release device fabricated using nanopore thin film and layer-by-layer (LbL) nanoassembly is reported. The nanopore thin film is a layer of anodic aluminum oxide (AAO), consisting of honeycomb-shape nanopores. Using the LbL nanoassembly process, the drug, using gentamicin sulfate (GS) as the model, can be loaded into the nanopores and the stacked layers on the nanopore thin film surface. The drug release from the device is achieved by immersing it into flowing DI water. Both the loading and release processes can be monitored optically. The effect of the nanopore size/volume on drug loading and release has also been evaluated. Further, the neuron cells have been cultured and can grow normally on the nanopore thin film, verifying its bio-compatibility. The successful fabrication of nanopore thin film device on silicon membrane render it as a potential implantable controlled drug release device.

The effect of capsaicin application on mast cells in normal human skin.

PubMed

Bunker, C B; Cerio, R; Bull, H A; Evans, J; Dowd, P M; Foreman, J C

1991-05-01

Peptides released from sensory nerves during an axon reflex are thought to cause mast cell degranulation, histamine (Hi) release and Hi-induced vasodilatation leading to the flare of the triple response. Capsaicin stimulates peptide release from sensory neurones and causes flare in vivo but does not cause Hi release from mast cells in vitro. The effects of capsaicin on mast cell degranulation in human skin in vivo has been studied by histological examination of skin biopsies after topical capsicin (1%) treatment of stratum corneum-denuded forearm in four volunteers. The results show a significant reduction in the visible numbers of mast cells and the appearance of degranulated mast cells ghosts in the skin six hours after capsaicin application. Since capsaicin itself does not release Hi from mast cells, these data suggest that capsaicin-induced release of peptides from neurones could cause mast cell degranulation.

Correlation of individual differences in schizotypal personality traits with amphetamine-induced dopamine release in striatal and extrastriatal brain regions.

PubMed

Woodward, Neil D; Cowan, Ronald L; Park, Sohee; Ansari, M Sib; Baldwin, Ronald M; Li, Rui; Doop, Mikisha; Kessler, Robert M; Zald, David H

2011-04-01

Schizotypal personality traits are associated with schizophrenia spectrum disorders, and individuals with schizophrenia spectrum disorders demonstrate increased dopamine transmission in the striatum. The authors sought to determine whether individual differences in normal variation in schizotypal traits are correlated with dopamine transmission in the striatum and in extrastriatal brain regions. Sixty-three healthy volunteers with no history of psychiatric illness completed the Schizotypal Personality Questionnaire and underwent positron emission tomography imaging with [(18)F]fallypride at baseline and after administration of oral d-amphetamine (0.43 mg/kg). Dopamine release, quantified by subtracting each participant's d-amphetamine scan from his or her baseline scan, was correlated with Schizotypal Personality Questionnaire total and factor scores using region-of-interest and voxel-wise analyses. Dopamine release in the striatum was positively correlated with overall schizotypal traits. The association was especially robust in the associative subdivision of the striatum. Voxel-wise analyses identified additional correlations between dopamine release and schizotypal traits in the left middle frontal gyrus and left supramarginal gyrus. Exploratory analyses of Schizotypal Personality Questionnaire factor scores revealed correlations between dopamine release and disorganized schizotypal traits in the striatum, thalamus, medial prefrontal cortex, temporal lobe, insula, and inferior frontal cortex. The association between dopamine signaling and psychosis phenotypes extends to individual differences in normal variation in schizotypal traits and involves dopamine transmission in both striatal and extrastriatal brain regions. Amphetamine-induced dopamine release may be a useful endophenotype for investigating the genetic basis of schizophrenia spectrum disorders.

Familial secondary erythrocytosis due to increased oxygen affinity is caused by destabilization of the T state of hemoglobin Brigham (α2β2Pro100Leu)

PubMed Central

Mollan, Todd L; Abraham, Bindu; Strader, Michael Brad; Jia, Yiping; Lozier, Jay N; Olson, John S; Alayash, Abdu I

2012-01-01

Hemoglobin Brigham (β Pro100 to Leu) was first reported in a patient with familial erythrocytosis. Erythrocytes of an affected individual from the same family contain both HbA and Hb Brigham and exhibit elevated O2 affinity compared with normal cells (P50 = 23 mm Hg vs. 31 mmHg at pH 7.4 at 37°C). O2 affinities measured for hemolysates were sensitive to changes in pH or chloride concentrations, indicating little change in the Bohr and Chloride effects. Hb Brigham was separated from normal HbA by nondenaturing cation exchange liquid chromatography, and the amino acid substitution was verified by mass spectrometry. The properties of Hb Brigham isolated from the patient's blood were then compared with those of recombinant Hb Brigham expressed in Escherichia coli. Kinetic experiments suggest that the rate constants for ligand binding and release in the high (R) and low (T) affinity quaternary states of Hb Brigham are similar to those of native hemoglobin. However, the Brigham mutation decreases the T to R equilibrium constant (L) which accelerates the switch to the R state during ligand binding to deoxy-Hb, increasing the rate of association by approximately twofold, and decelerates the switch during ligand dissociation from HbO2, decreasing the rate approximately twofold. These kinetic data help explain the high O2 affinity characteristics of Hb Brigham and provide further evidence for the importance of the contribution of Pro100 to intersubunit contacts and stabilization of the T quaternary structure. PMID:22821886

Development of theophylline sustained release dosage form based on Kollidon SR.

PubMed

Reza, Md Selim; Quadir, Mohiuddin Abdul; Haider, Syed Shabbir

2002-01-01

Sustained release theophylline matrix tablets constituting Kollidon SR (Polyvinyl acetate and povidone based matrix retarding polymer) were developed in this study in an attempt to design a dosage form that manifests desirable release profile and thorough adherence to official monographs. Four matrix tablet formulations were prepared by dry blending and direct compression of Kollidon SR and HPMC-15cps (hydroxypropylmethylcellulose) in varying proportion with fixed percentage of theophylline. Tablets containing only Kollidon SR with the active ingredient demonstrated a rapid rate of drug release with an initial burst effect. Incorporation of HPMC-15cps in the matrix tablet prolonged the release of drug with subsequent minimization of burst effect as confirmed by mean dissolution time, T50 and Higuchi release rate data. Among the batches containing HPMC-15 cps, a direct relationship was obtained between release rate and the percentage of HPMC used. A suitable controlled release profile was obtained with the matrix tablets containing 20% Kollidon SR and 30% HPMC-15cps. The formulation showed close resemblance to commercial products and compliance with USP specification. The results were explored and explained by the difference of physico-chemical property and hydration characteristics of the polymers. In addition to this result, the exponential model was applied to characterize the drug release behaviour from polymeric systems. It was found that, Fickian release is predominant in tablets containing Kollidon SR alone and non-Fickian mechanism plays an important role in the release of drug from HPMC containing tablets with a trend towards zero-order or case II release. In vitro release profile of two commercial brands were also undertaken for comparison and modulation of the experimental batches.

Xylan-Modified-Based Hydrogels with Temperature/pH Dual Sensitivity and Controllable Drug Delivery Behavior

PubMed Central

Kong, Wei-Qing; Gao, Cun-Dian; Hu, Shu-Feng; Ren, Jun-Li; Zhao, Li-Hong; Sun, Run-Cang

2017-01-01

Among the natural macromolecules potentially used as the scaffold material in hydrogels, xylan has aroused great interest in many fields because of its biocompatibility, low toxicity, and biodegradability. In this work, new pH and thermoresponsive hydrogels were prepared by the cross-linking polymerization of maleic anhydride-modified xylan (MAHX) with N-isopropylacrylamide (NIPAm) and acrylic acid (AA) under UV irradiation to form MAHX-g-P(NIPAm-co-AA) hydrogels. The pore volume, the mechanical properties, and the release rate for drugs of hydrogels could be controlled by the degree of substitution of MAHX. These hydrogels were characterized by swelling ability, lower critical solution temperature (LCST), Fourier-transform infrared (FTIR), and SEM. Furthermore, the cumulative release rate was investigated for acetylsalicylic acid and theophylline, as well as the cytocompatibility MAHX-based hydrogels. Results showed that MAHX-based hydrogels exhibited excellent swelling–deswelling properties, uniform porous structure, and the temperature/pH dual sensitivity. In vitro, the cumulative release rate of acetylsalicylic acid for MAHX-based hydrogels was higher than that for theophylline, and in the gastrointestinal sustained drug release study, the acetylsalicylic acid release rate was extremely slow during the initial 3 h in the gastric fluid (24.26%), and then the cumulative release rate reached to 90.5% after sustained release for 5 h in simulated intestinal fluid. The cytotoxicity experiment demonstrated that MAHX-based hydrogels could promote cell proliferation and had satisfactory biocompatibility with NIH3T3 cells. These results indicated that MAHX-based hydrogels, as new drug carriers, had favorable behavior for intestinal-targeted drug delivery. PMID:28772664

A Method for Calculating Strain Energy Release Rates in Preliminary Design of Composite Skin/Stringer Debonding Under Multi-Axial Loading

NASA Technical Reports Server (NTRS)

Krueger, Ronald; Minguet, Pierre J.; OBrien, T. Kevin

1999-01-01

Three simple procedures were developed to determine strain energy release rates, G, in composite skin/stringer specimens for various combinations of unaxial and biaxial (in-plane/out-of-plane) loading conditions. These procedures may be used for parametric design studies in such a way that only a few finite element computations will be necessary for a study of many load combinations. The results were compared with mixed mode strain energy release rates calculated directly from nonlinear two-dimensional plane-strain finite element analyses using the virtual crack closure technique. The first procedure involved solving three unknown parameters needed to determine the energy release rates. Good agreement was obtained when the external loads were used in the expression derived. This superposition technique was only applicable if the structure exhibits a linear load/deflection behavior. Consequently, a second technique was derived which was applicable in the case of nonlinear load/deformation behavior. The technique involved calculating six unknown parameters from a set of six simultaneous linear equations with data from six nonlinear analyses to determine the energy release rates. This procedure was not time efficient, and hence, less appealing. A third procedure was developed to calculate mixed mode energy release rates as a function of delamination lengths. This procedure required only one nonlinear finite element analysis of the specimen with a single delamination length to obtain a reference solution for the energy release rates and the scale factors. The delamination was extended in three separate linear models of the local area in the vicinity of the delamination subjected to unit loads to obtain the distribution of G with delamination lengths. This set of sub-problems was Although additional modeling effort is required to create the sub- models, this local technique is efficient for parametric studies.

Superresolution Modeling of Calcium Release in the Heart

PubMed Central

Walker, Mark A.; Williams, George S.B.; Kohl, Tobias; Lehnart, Stephan E.; Jafri, M. Saleet; Greenstein, Joseph L.; Lederer, W.J.; Winslow, Raimond L.

2014-01-01

Stable calcium-induced calcium release (CICR) is critical for maintaining normal cellular contraction during cardiac excitation-contraction coupling. The fundamental element of CICR in the heart is the calcium (Ca2+) spark, which arises from a cluster of ryanodine receptors (RyR). Opening of these RyR clusters is triggered to produce a local, regenerative release of Ca2+ from the sarcoplasmic reticulum (SR). The Ca2+ leak out of the SR is an important process for cellular Ca2+ management, and it is critically influenced by spark fidelity, i.e., the probability that a spontaneous RyR opening triggers a Ca2+ spark. Here, we present a detailed, three-dimensional model of a cardiac Ca2+ release unit that incorporates diffusion, intracellular buffering systems, and stochastically gated ion channels. The model exhibits realistic Ca2+ sparks and robust Ca2+ spark termination across a wide range of geometries and conditions. Furthermore, the model captures the details of Ca2+ spark and nonspark-based SR Ca2+ leak, and it produces normal excitation-contraction coupling gain. We show that SR luminal Ca2+-dependent regulation of the RyR is not critical for spark termination, but it can explain the exponential rise in the SR Ca2+ leak-load relationship demonstrated in previous experimental work. Perturbations to subspace dimensions, which have been observed in experimental models of disease, strongly alter Ca2+ spark dynamics. In addition, we find that the structure of RyR clusters also influences Ca2+ release properties due to variations in inter-RyR coupling via local subspace Ca2+ concentration ([Ca2+]ss). These results are illustrated for RyR clusters based on super-resolution stimulated emission depletion microscopy. Finally, we present a believed-novel approach by which the spark fidelity of a RyR cluster can be predicted from structural information of the cluster using the maximum eigenvalue of its adjacency matrix. These results provide critical insights into CICR dynamics in heart, under normal and pathological conditions. PMID:25517166

Assessment of menstrual blood loss in Belgian users of a new T-shaped levonorgestrel-releasing intrauterine system.

PubMed

Wildemeersch, Dirk; Rowe, Patrick J

2005-06-01

This study was conducted to evaluate the effect of a T-shaped levonorgestrel-releasing intrauterine system (Femilis, LNG IUS) on the amount of menstrual blood loss (MBL) in women with and without menorrhagia. The daily release of the LNG IUS was approximately 20 mug. In 60 Belgian women, less than 48 years of age at study enrollment, using the Femilis LNG IUS for 4 to more than 30 months, MBL was assessed with the visual assessment technique. Twenty-eight women had normal menstrual periods at baseline (menstrual score <185) and 32 women had idiopathic menorrhagia (menstrual score > or =185). Menstrual blood loss scores dropped significantly during the observation period in all women except one. The median menstrual score at baseline in women with normal menstrual bleeding was 140 (range 80-160) and dropped to a median score of 5 (range 0-150) at follow-up, a decrease of 96%. In the 32 women with menorrhagic bleeding at baseline, menstrual flow dropped from a median score of 232 (range 185-450) at baseline to a median score of 3 (range 0-50) at follow-up, a decrease of 99%. Twenty women developed amenorrhea (33%): 10 in the group of women with normal menstruation and 10 in those women with menorrhagia. Most of the remaining women had oligomenorrhea requiring the use of a few panty-liners only. In one woman, MBL did not decrease, thus requiring further evaluation. The impact on MBL of this new 20 mug/day LNG-releasing IUS confirms other studies with devices releasing the same or lower amounts of LNG. The strong endometrial suppression is the principal mechanism explaining the effect on MBL. The strong effect on MBL of this contraceptive method offers an important health benefit and improvement in quality of life, particularly in women with heavy bleeding and anemia, as other treatment modalities are less effective, more costly, more invasive or not readily available.

Assessing the release of copper from nanocopper-treated and conventional copper-treated lumber into marine waters I: Concentrations and rates.

PubMed

Parks, Ashley N; Cantwell, Mark G; Katz, David R; Cashman, Michaela A; Luxton, Todd P; Ho, Kay T; Burgess, Robert M

2018-03-25

Little is known about the release of metal engineered nanomaterials (ENMs) from consumer goods, including lumber treated with micronized copper. Micronized copper is a recent form of antifouling wood preservative containing nanosized copper particles for use in pressure-treated lumber. The present study investigated the concentrations released and the release rate of total copper over the course of 133 d under freshwater, estuarine, and marine salinity conditions (0, 1, 10, and 30‰) for several commercially available pressure-treated lumbers: micronized copper azole (MCA) at 0.96 and 2.4 kg/m 3 , alkaline copper quaternary (ACQ) at 0.30 and 9.6 kg/m 3 , and chromated copper arsenate (CCA) at 40 kg/m 3 . Lumber was tested as blocks and as sawdust. Overall, copper was released from all treated lumber samples. Under leaching conditions, total release ranged from 2 to 55% of the measured copper originally in the lumber, with release rate constants from the blocks of 0.03 to 2.71 (units per day). Generally, measured release and modeled equilibrium concentrations were significantly higher in the estuarine conditions compared with freshwater or marine salinities, whereas rate constants showed very limited differences between salinities. Furthermore, organic carbon was released during the leaching and demonstrated a significant relationship with released copper concentrations as a function of salinity. The results indicate that copper is released into estuarine/marine waters from multiple wood treatments including lumber amended with nanoparticle-sized copper. Environ Toxicol Chem 2018;9999:1-13. Published 2018 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America. Published 2018 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

Pharmacokinetics and effect of food after oral administration of prolonged-release tablets of ropinirole hydrochloride in Japanese patients with Parkinson's disease.

PubMed

Hattori, N; Hasegawa, K; Sakamoto, T

2012-10-01

Ropinirole hydrochloride, a dopamine receptor agonist with a non-ergot alkaloid structure, is highly selective for the dopamine D(2) /D(3) receptors. This study was conducted to evaluate the steady-state pharmacokinetics, safety and efficacy after repeated oral administration of prolonged-release tablets of ropinirole hydrochloride in the absence of L-dopa preparations in Japanese patients with Parkinson's disease (PD). This was a multicenter, open-label, uncontrolled study. The total duration of participation in the study ranged from 56 to 63 weeks. In the study, the plasma concentrations of ropinirole, its major metabolite SK&F104557 (N-depropyl ropinirole) and another metabolite SK&F89124 (ropinirole hydroxylated at the seventh position of the indole ring) were assessed. Safety based on adverse events, haematology, biochemistry, urinalysis and electrocardiography (ECG) (standard 12-lead ECG) were evaluated, and vital signs (blood pressure/pulse rate) were measured. Efficacy based on the Japanese version of Unified Parkinson's Disease Rating Scale (UPDRS) Parts III (motor) and II [activities of daily living (ADL)] as well as tolerability was evaluated. After repeated oral administration of prolonged-release tablets of ropinirole hydrochloride in Japanese patients with PD, ropinirole, SK&F104557 and low levels of SK&F89124 were detected in plasma. The trough concentrations of ropinirole and the two metabolites increased in proportion to the dose when ropinirole hydrochloride prolonged-release tablets were administered at doses ranging from 2 to 16 mg/day. The plasma exposure to ropinirole and its two metabolites after intake of normal diet was comparable to that in the fasting state. The most common adverse events (10% or more) were somnolence, nausea, constipation, hallucination and nasopharyngitis. Most adverse events were mild or moderate in severity, and with no death. During the treatment period, serious adverse events were reported in five patients. Efficacy analysis (LOCF) at the final endpoint up to week 16 demonstrated a mean (SD) change from baseline in the Japanese UPDRS III (motor) and II (ADL) scores of -11·3 (8·21) and -3·9 (3·22), respectively, and thereafter remained at similar levels until week 52. After administration of prolonged-release tablets of ropinirole hydrochloride in the absence of L-dopa preparations in Japanese patients with PD, the plasma pharmacokinetics of ropinirole and its metabolites was linear and not affected by food. Compared with the immediate-release (IR) tablet, the prolonged-release tablet can be administered to Japanese patients with PD at a reduced daily dose frequency and adjusted to the maintenance dose after fewer dose changes with a smaller diurnal variation in the plasma ropinirole concentration. © 2012 Blackwell Publishing Ltd.

A novel system to diagnose cutaneous adverse drug reactions employing the cellscan--comparison with histamine releasing test and Inf-gamma Releasing Test.

PubMed

Goldberg, Ilan; Gilburd, Boris; Kravitz, Martine Szyper; Kivity, Shmuel; Chaim, Berta Ben; Klein, Tirza; Schiffenbauer, Yael; Trubniykovr, Ela; Brenner, Sarah; Shoenfeld, Yehuda

2005-03-01

There are several mechanisms to describe allergic drug reactions yet the methods to diagnose them are limited. To compare several conventional clinical and laboratory methods to diagnose skin reactions to drugs to a new method of diagnosing drug reactions by the CellScan system. The study entailed 21 patients who were diagnosed as suffering from drug eruptions, and 105 healthy controls with no history of drug allergy. The drugs were classified into two groups according to suspicion of causing drug allergy: high and low. Most of the patients were on more than one drug, leading to 41 patient-drug interactions (assays). Histamine releasing test (HRT), interferon (INF)-gamma releasing test and CellScan examination were performed on lymphocytes of the patients and controls. The HRTwas interpreted as positive in 9 out of 18 (50%) patients and in 13 out of 35 (37%) assays. Based on the INF-gamma releasing test, positive results were observed in 16 out of 21 (76%) patients and in 24 out of 41 (59%) assays. In the CellScan test (CST), positive results were observed in 17 out of 21 (81%) patients and in 29 out of 41 (71%) assays. The rate of identifying the drug for eruption in the high suspicion level drugs was 9 out of 22 (41%) assays in the HRT, 20 out of 24 (83%) assays in the INF-gamma releasing test, and 21 out of 24 (87%) studies with the CellScan method. The rate of determining of the drug that caused the eruption in the low suspicion level drugs was 4 out of 13 (31 %) in the HRT, 4 out of 17 (24%) assays in the INF-gamma releasing test, and 8 out of 17 (47%) analyses in the CST. When examined in the CellScan, 99 out of 105 (94%) controls were interpreted as negative. This preliminary study indicates that the CellScan seems to be an easy and promising method for the detection of drugs responsible for adverse skin reactions. In contrast to the HRT and to the Interferon-gamma secretion test, the CellScan method is characterized by its ability to track and monitor the reaction of individual cells. By measuring the kinetic parameters of selected cells before and after adding the suspected drug, we were able to identify the culprit drug. The CellScan method had the highest sensitivity, and the interferon-gamma secretion test had the highest specificity for detection of the culprit drug. In contrast, the analysis of 105 normal control sera disclosed a high specificity of 94% for the CellScan method.

Influence of Strain Rate on Heat Release under Quasi-Static Stretching of Metals. Experiment

NASA Astrophysics Data System (ADS)

Zimin, B. A.; Sventitskaya, V. E.; Smirnov, I. V.; Sud'enkov, Yu. V.

2018-04-01

The paper presents the results of experimental studies of energy dissipation during a quasi-static stretching of metals and alloys at room temperature. The strain rates varied in the range of 10-3-10-2 s-1. Samples of M1 copper, AZ31B magnesium alloy, BT6 titanium, 12Cr18Ni10Ti steel, and D16AM aluminum alloy were analyzed. The experimental results demonstrated a significant dependence of the heat release on the strain rate in the absence of its influence on stress-strain diagrams for all the metals studied in this range of strain rates. The correlation of the changes in the character of heat release with the processes of structural transformations at various stages of plastic flow is shown on the qualitative level. A difference in the nature of the processes of heat release in materials with different ratios of the plasticity and strength is noted.

SP industry calorimeter for rate of heat release measurements up to 10MW

NASA Astrophysics Data System (ADS)

Dahlberg, Martin

The Swedish National Testing and Research Institute (SP) has installed a 10 MW fire calorimeter for rate of heat release measurements, similar to the one at Factory Mutual Research Corporation (FMRC). It can be used to classify commodities with respect to their fire hazard, to evaluate the efficiency of sprinkler systems, for chemical analysis of the combustion gases from hazardous fires, to produce input data for the fire modelling, etc. A large hood collects the fire gases and leads them into a duct where gas velocity, gas temperature, smoke density, and contents of oxygen, carbon dioxide, and carbon monoxide are measured. On the basis of these measurements, mass flow and rate of heat release are calculated. The rate of heat release is calculated according to the oxygen consumption principle. The upper limit for measurements is approximately 10 MW and the lower is 0.1 MW.

A novel fibrinogen variant--Liberec: dysfibrinogenaemia associated with gamma Tyr262Cys substitution.

PubMed

Kotlín, Roman; Sobotková, Alzbeta; Suttnar, Jirí; Salaj, Peter; Walterová, Lenka; Riedel, Tomás; Reicheltová, Zuzana; Dyr, Jan Evangelista

2008-08-01

A 22-yr-old woman had abnormal preoperative coagulation test results and congenital dysfibrinogenaemia was suspected. The patient from Liberec (Czech Republic) had a low fibrinogen plasma level as determined by Clauss method, normal fibrinogen level as determined by immunoturbidimetrical method, and prolonged thrombin time. To identify the genetic mutation responsible for this dysfibrinogen, genomic DNA extracted from the blood was analysed. Fibrin polymerisation measurement, kinetics of fibrinopeptide release, fibrinogen clottability measurement and scanning electron microscopy were performed. DNA sequencing showed the heterozygous fibrinogen gamma Y262C mutation. Kinetics of fibrinopeptide release was normal, however fibrin polymerisation was impaired. Fibrinogen clottability measurement showed that only about 45% molecules of fibrinogen are involved in the clot formation. Scanning electron microscopy revealed thicker fibres, which were significantly different from the normal control. A case of dysfibrinogenaemia, found by routine coagulation testing, was genetically identified as a novel fibrinogen variant (gamma Y262C) that has been named Liberec.

Speech Rate Normalization and Phonemic Boundary Perception in Cochlear-Implant Users.

PubMed

Jaekel, Brittany N; Newman, Rochelle S; Goupell, Matthew J

2017-05-24

Normal-hearing (NH) listeners rate normalize, temporarily remapping phonemic category boundaries to account for a talker's speech rate. It is unknown if adults who use auditory prostheses called cochlear implants (CI) can rate normalize, as CIs transmit degraded speech signals to the auditory nerve. Ineffective adjustment to rate information could explain some of the variability in this population's speech perception outcomes. Phonemes with manipulated voice-onset-time (VOT) durations were embedded in sentences with different speech rates. Twenty-three CI and 29 NH participants performed a phoneme identification task. NH participants heard the same unprocessed stimuli as the CI participants or stimuli degraded by a sine vocoder, simulating aspects of CI processing. CI participants showed larger rate normalization effects (6.6 ms) than the NH participants (3.7 ms) and had shallower (less reliable) category boundary slopes. NH participants showed similarly shallow slopes when presented acoustically degraded vocoded signals, but an equal or smaller rate effect in response to reductions in available spectral and temporal information. CI participants can rate normalize, despite their degraded speech input, and show a larger rate effect compared to NH participants. CI participants may particularly rely on rate normalization to better maintain perceptual constancy of the speech signal.

Effects of polyvinylpyrrolidone both as a binder and pore-former on the release of sparingly water-soluble topiramate from ethylcellulose coated pellets.

PubMed

Yang, Meiyan; Xie, Si; Li, Qiu; Wang, Yuli; Chang, Xinyi; Shan, Li; Sun, Lei; Huang, Xiaoli; Gao, Chunsheng

2014-04-25

Delivering sparingly water-soluble drugs from ethylcellulose (EC) coated pellets with a controlled-release pattern remains challenging. In the present study, hydrophilic polyvinylpyrrolidone (PVP) was used both as a binder and a pore-former in EC coated pellets to deliver sparingly water-soluble topiramate, and the key factors that influenced drug release were identified. When the binder PVP content in drug layers below 20% w/w was decreased, the physical state of topiramate changed from amorphous to crystalline, making much difference to drug solubility and dissolution rates while modifying the drug release profile from first-order to zero-order. In addition, without PVP in drug layering solution, drug layered particles were less sticky during layering process, thus leading to a shorter process and higher loading efficiency. Furthermore, PVP level as a pore-former in EC coating layers mainly governed drug release from the coated pellets with the sensitivity ranging from 23% to 29%. PVP leaching rate and water permeability from EC/PVP film increased with the PVP level, which was perfectly correlated with drug release rate. Additionally, drug release from this formulation was independent of pH of release media or of the paddle mixing speed, but inversely proportional to the osmolality of release media above the physiological range. Copyright © 2014. Published by Elsevier B.V.

Cardiac Responses to Thermal, Physical, and Emotional Stress

PubMed Central

Taggart, Peter; Parkinson, Peter; Carruthers, Malcolm

1972-01-01

We have studied the effect of a short period of exposure to the intense heat of a sauna bath on the electrocardiogram and plasma catecholamine, free fatty acid, and triglyceride concentrations in 17 subjects with apparently normal hearts and 18 persons with coronary heart disease. Similar observations were made on 11 of the 17 normal subjects and on 7 of the persons with coronary heart disease in response to exercise. Exposure to heat was associated with an increase in plasma adrenaline with no change in noradrenaline, free fatty acid, or triglyceride concentrations. Exercise was associated with the expected increase in both plasma noradrenaline and adrenaline concentrations. A heart rate up to 180 beats/min was observed in response to both heat and exercise. Apart from the ST-T changes inherent to sinus tachycardia, ST-T segment abnormalities were frequent in response to heat in both the subjects with normal and abnormal hearts, but little change occurred in the ST-T configuration when the subjects were exercised to produce comparable heart rates. Ectopic beats, sometimes numerous and multifocal, were observed in some subjects of both groups in response to heat, but not to exercise. It seems likely that the net unbalanced adrenaline component of the increased plasma catecholamine concentrations (which is also seen in certain emotional stress situations) is predominantly responsible for ischaemic-like manifestations of the electrocardiogram in susceptible subjects. The observations provide further validation for previously reported studies that it is the increased plasma noradrenaline in response to emotional stress that is associated with the release of free fatty acids and ultimate hypertriglyceridaemia, of probable importance in the aetiology of atheroma. ImagesFIG. 1FIG. 2FIG. 3FIG. 4FIG. 5FIG. 6 PMID:4114377

Nitric Oxide Releasing Coronary Stent: A New Approach Using Layer-by-Layer Coating and Liposomal Encapsulation.

PubMed

Elnaggar, Mahmoud A; Seo, Seong Ho; Gobaa, Samy; Lim, Kyung Seob; Bae, In-Ho; Jeong, Myung Ho; Han, Dong Keun; Joung, Yoon Ki

2016-11-01

The sustained or controlled release of nitric oxide (NO) can be the most promising approach for the suppression or prevention of restenosis and thrombosis caused by stent implantation. The aim of this study is to investigate the feasibility in the potential use of layer-by-layer (LBL) coating with a NO donor-containing liposomes to control the release rate of NO from a metallic stent. Microscopic observation and surface characterizations of LBL-modified stents demonstrate successful LBL coating with liposomes on a stent. Release profiles of NO show that the release rate is sustained up to 5 d. In vitro cell study demonstrates that NO release significantly enhances endothelial cell proliferation, whereas it markedly inhibits smooth muscle cell proliferation. Finally, in vivo study conducted with a porcine coronary injury model proves the therapeutic efficacy of the NO-releasing stents coated by liposomal LBL technique, supported by improved results in luminal healing, inflammation, and neointimal thickening except thrombo-resistant effect. As a result, all these results demonstrate that highly optimized release rate and therapeutic dose of NO can be achieved by LBL coating and liposomal encapsulation, followed by significantly efficacious outcome in vivo. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simplified modeling of blast waves from metalized heterogeneous explosives

NASA Astrophysics Data System (ADS)

Zarei, Z.; Frost, D. L.

2011-09-01

The detonation of a metalized explosive generates a complex multiphase flow field. Modeling the subsequent propagation of the blast front requires a detailed knowledge of the metal particle dynamics and reaction rate. Given the uncertainties in modeling these phenomena, a much simpler, 1D compressible flow model is used to illustrate the general effects of secondary energy release due to particle reaction on the blast front properties. If the total energy release is held constant, the blast pressure and impulse are primarily dependent on the following parameters: the proportion of secondary energy released due to afterburning, the rate of energy release, the location the secondary energy release begins, and the range over which it occurs. Releasing the total energy over a longer time period in general reduces the peak blast overpressure at a given distance. However, secondary energy release reduces the rate of decay of the shock pressure, increases the local gas temperature and hence increases the velocity of the secondary shock front. As a result, for certain values of the above parameters, the peak blast impulse may be increased by a factor of about two in a region near the charge. The largest augmentation to the near-field peak impulse results when the secondary energy is released immediately behind the shock front rather than uniformly within the combustion products.

Variables that affect the mechanism of drug release from osmotic pumps coated with acrylate/methacrylate copolymer latexes.

PubMed

Jensen, J L; Appel, L E; Clair, J H; Zentner, G M

1995-05-01

The feasibility of using modified Eudragit acrylic latexes as microporous coatings for osmotic devices was investigated. Potassium chloride tablets were coated with mixtures of Eudragit RS30D and RL30D acrylic latexes that also contained a plasticizer (triethyl citrate or acetyl tributyl citrate) and a pore-forming agent (urea). A 2(5-1) fractional factorial experimental design was employed to determine the effect of five formulation variables (RS30D:RL30D polymer ratio plasticizer type, plasticizer level, urea level, and cure) on the in vitro release rate of KCl in deionized water (di water), lag time, and coat burst strength. The RS30D:RL30D polymer ratio had the greatest effect on the release rate, and both lag time and burst strength were most affected by the urea level. Statistical optimization was performed, and a coat formulation with predicted desirable in vitro performance was prepared and tested. The in vitro release rate (di water), lag time, and coat burst strength agreed well with the prediction. Dissolutions were also performed in phosphate buffered saline (PBS; pH 7.4); several formulations released markedly slower in PBS than in di water. This discrepancy was dependent on the type of plasticizer and the amount of pore former. Only those coat formulations containing acetyl tributyl citrate as the plasticizer and a 100% urea [(g urea/g polymer solids) x 100] level exhibited similar release rates in di water and PBS. The mechanism of release from these devices was primarily osmotic, whereas the release from devices coated with a formulation containing triethyl citrate and 50% urea was not dependent on the osmotic pressure difference. Devices with an osmotic release mechanism behaved similarly in vivo and in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of Matrix Tablets Based on Eudragit®E100/Carbopol®971P Combinations for Controlled Release and Improved Compaction Properties of Water Soluble Model Drug Paracetamol.

PubMed

Obeidat, Wasfy M; Nokhodchi, Ali; Alkhatib, Hatim

2015-10-01

The purpose of this work was to investigate the influence of Eudragit®E100 polymer in modifying the release rates and compaction properties of water soluble model drug paracetamol from Carbopol®971P NF polymer matrix tablets prepared by direct compression. The effects of the ratio of the two polymers, the total polymeric content, and the tablets mechanical strength on paracetamol release rates were investigated. Dissolution studies were conducted using USP XX Π rotating paddle apparatus at 50 rpm and 37°C at three different stages (pH 1.2, 4.8, and 6.8). Results showed that the polymers combination improved significantly the compaction properties of paracetamol tablets as evident by the higher crushing strengths (8.3 ± 0.4 Kp) compared to polymer-free tablets (3.4 ± 0.2 Kp) at intermediate compression pressure of 490 MPa. When combined with Carbopol®971P NF, Eudragit®E100 was found to be capable of extending paracetamol release for more than 12 h compared to 1 h for polymers-free tablets. The combined polymers were able to control paracetamol release in a pH independent pattern. The f2 (similarity factor) analysis showed that the ratio between the polymers and the total polymer concentration exhibited significant impact on drug release rates. In conclusion, Eudragit®E100 when combined with Carbopol®971P NF was capable of improving the compaction and sustained release properties of paracetamol. Korsmeyer-Peppas model was found to be the most suitable for fitting drug release data. The polymer combinations can potentially be used to control the release rates of highly water soluble drugs.

Active adaptive management for reintroduction of an animal population

USGS Publications Warehouse

Runge, Michael C.

2013-01-01

Captive animals are frequently reintroduced to the wild in the face of uncertainty, but that uncertainty can often be reduced over the course of the reintroduction effort, providing the opportunity for adaptive management. One common uncertainty in reintroductions is the short-term survival rate of released adults (a release cost), an important factor because it can affect whether releasing adults or juveniles is better. Information about this rate can improve the success of the reintroduction program, but does the expected gain offset the costs of obtaining the information? I explored this question for reintroduction of the griffon vulture (Gyps fulvus) by framing the management question as a belief Markov decision process, characterizing uncertainty about release cost with 2 information state variables, and finding the solution using stochastic dynamic programming. For a reintroduction program of fixed length (e.g., 5 years of releases), the optimal policy in the final release year resembles the deterministic solution: release either all adults or all juveniles depending on whether the point estimate for the survival rate in question is above or below a specific threshold. But the optimal policy in the earlier release years 1) includes release of a mixture of juveniles and adults under some circumstances, and 2) recommends release of adults even when the point estimate of survival is much less than the deterministic threshold. These results show that in an iterated decision setting, the optimal decision in early years can be quite different from that in later years because of the value of learning.