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Sample records for absorption window drug

  1. Optimization of a dual mechanism gastrofloatable and gastroadhesive delivery system for narrow absorption window drugs.

    PubMed

    Murphy, Caragh; Pillay, Viness; Choonara, Yahya E; du Toit, Lisa C; Ndesendo, Valence M K; Chirwa, Nthato; Kumar, Pradeep

    2012-03-01

    In order to overcome poor bioavailability of narrow absorption window drugs, a gastrosphere system comprising two mechanisms of gastric retention, namely buoyancy and gastroadhesion, has been investigated in this study employing poly(lactic-co-glycolic acid) (PLGA), polyacrylic acid (PAA), alginate, pectin, and a model drug metformin hydrochloride. Fifteen formulations were obtained using a Box-Behnken statistical design. The gastrosphere yield was above 80% in all cases; however, due to the high water solubility of metformin, drug entrapment efficacy was between 18% and 54%. Mean dissolution time and gastroadhesive strength were used as the formulation responses in order to optimize the formulation. Furthermore, the molecular mechanics force field simulations were performed to corroborate the experimental findings. Drug release profiles revealed three different release kinetics, namely, burst, first-order and zero-order release. Varying gastroadhesive results were obtained, and were highly sensitive to changes in polymer concentrations. FTIR revealed that strong bonds of PAA and PLGA were retained within the gastrosphere. Surface area and porosity analysis provided supporting evidence that the lyophilization process resulted in a significant increase in the porosity. Analysis of the surface morphology by SEM revealed that air pockets were spread over the entire surface of the gastrosphere, providing a visual proof of the high porosity and hence low density of the gastrosphere. The spatial disposition and energetic profile of the sterically constrained and geometrically optimized multi-polymeric complex of alginate, pectin, PAA, and PLGA corroborated the experimental results in terms of in vitro drug release and gastroadhesive strength of the fabricated gastrospheres. PMID:22048877

  2. Statistical Design of Experiments on Fabrication of Bilayer Tablet of Narrow Absorption Window Drug: Development and In vitro characterisation

    PubMed Central

    Jivani, R. R.; Patel, C. N.; Jivani, N. P.

    2012-01-01

    The current study involves the fabrication of oral bioadhesive bilayer matrices of narrow absorption window drug baclofen and the optimisation of their in vitro drug release and characterisation. Statistical design of experiments, a computer-aided optimisation technique, was used to identify critical factors, their interactions and ideal process conditions that accomplish the targeted response(s). A central composite design was employed to systematically optimise the drug delivery containing a polymer, filler and compression force. The values of ratio of different grades of hydroxypropyl methylcellulose, microcrystalline cellulose and compression force were varied to be fitted in design. Drug release at 1 h (Q1), 4 h (Q4), 8 h (Q8), 12 h (Q12), and hardness were taken as responses. Tablets were prepared by direct compression methods. The compressed tablets were evaluated for their hardness, weight variation, friability, content uniformity and diameter. Counter plots were drawn and optimum formulation was selected by desirability function. The formulations were checked for their ex vivo mucoadhesion. The experimental value of Q1, Q4, Q8, Q12 and hardness for check-point batch was found to be 31.64, 45.82, 73.27, 98.95% and 4.4 kg/cm2, respectively. The release profile indicates Highuchi kinetics (Fickian transport) mechanism. The results of the statistical analysis of the data demonstrated significant interactions amongst the formulation variables, and the desirability function was demonstrated to be a powerful tool to predict the optimal formulation for the bilayer tablet. PMID:23626385

  3. Development and evaluation of a gastroretentive drug delivery system for the low-absorption-window drug celecoxib.

    PubMed

    Ali, Javed; Tyagi, Puneet; Ahuja, Alka; Baboota, Sanjula; Hasan, Sohail

    2007-01-01

    The objective of the present study is to develop microspheres for celecoxib to enhance its bioavailability by increasing its gastric residence time. Four different polymers-polyethylene oxide, Eudragit S, cellulose acetate, and Eudragit RL-were used to form the floating microspheres using an emulsion-solvent diffusion technique. The use of two different solvents (dichloromethane and ethanol) that differed in the rate of diffusion led to formation of a hollow core in the microspheres, which was partially responsible for the flotation ability. The formulation was optimized on the basis of in vitro buoyancy and in vitro release in simulated gastric fluid at pH 3. Scanning electron microscopy revealed differences between the formulations in terms of their topography. X-ray diffractometry and differential scanning calorimetry examination showed the amorphous nature of the drug. Microspheres prepared with polyethylene oxide:Eudragit S:celecoxib (2:2:1) gave the best in vitro percentage release and was taken as the optimized formulation. By fitting the data into zero order, first order, and Higuchi model, it could be concluded that the release followed first-order release kinetics. The correlation coefficient (R2 value) was obtained upon fitting the data to Higuchi equation, which signifies that the mechanism of release of celecoxib from the microspheres was diffusion rate-limited. PMID:17479716

  4. Recent Advances in Delivery Systems and Therapeutics of Cinnarizine: A Poorly Water Soluble Drug with Absorption Window in Stomach

    PubMed Central

    Pathak, Kamla

    2014-01-01

    Low solubility causing low dissolution in gastrointestinal tract is the major problem for drugs meant for systemic action after oral administration, like cinnarizine. Pharmaceutical products of cinnarizine are commercialized globally as immediate release preparations presenting low absorption with low and erratic bioavailability. Approaches to enhance bioavailability are widely cited in the literature. An attempt has been made to review the bioavailability complications and clinical therapeutics of poorly water soluble drug: cinnarizine. The interest of writing this paper is to summarize the pharmacokinetic limitations of drug with special focus on strategies to improvise bioavailability along with effectiveness of novel dosage forms to circumvent the obstacle. The paper provides insight to the approaches to overcome low and erratic bioavailability of cinnarizine by cyclodextrin complexes and novel dosage forms: self-nanoemulsifying systems and buoyant microparticulates. Nanoformulations need to systematically explored in future, for their new clinical role in prophylaxis of migraine attacks in children. Clinical reports have affirmed the role of cinnarizine in migraine prophylaxis. Research needs to be dedicated to develop dosage forms for efficacious bioavailability and drug directly to brain. PMID:25478230

  5. Percutaneous absorption of drugs.

    PubMed

    Wester, R C; Maibach, H I

    1992-10-01

    The skin is an evolutionary masterpiece of living tissue which is the final control unit for determining the local and systemic availability of any drug which must pass into and through it. In vivo in humans, many factors will affect the absorption of drugs. These include individual biological variation and may be influenced by race. The skin site of the body will also influence percutaneous absorption. Generally, those body parts exposed to the open environment (and to cosmetics, drugs and hazardous toxic substances) are most affected. Treating patients may involve single daily drug treatment or multiple daily administration. Finally, the body will be washed (normal daily process or when there is concern about skin decontamination) and this will influence percutaneous absorption. The vehicle of a drug will affect release of drug to skin. On skin, the interrelationships of this form of administration involve drug concentration, surface area exposed, frequency and time of exposure. These interrelationships determine percutaneous absorption. Accounting for all the drug administered is desirable in controlled studies. The bioavailability of the drug then is assessed in relationship to its efficacy and toxicity in drug development. There are methods, both quantitative and qualitative, in vitro and in vivo, for studying percutaneous absorption of drugs. Animal models are substituted for humans to determine percutaneous absorption. Each of these methods thus becomes a factor in determining percutaneous absorption because they predict absorption in humans. The relevance of these predictions to humans in vivo is of intense research interest. The most relevant determination of percutaneous absorption of a drug in humans is when the drug in its approved formulation is applied in vivo to humans in the intended clinical situation. Deviation from this scenario involves the introduction of variables which may alter percutaneous absorption. PMID:1296607

  6. Maximum entropy and drug absorption.

    PubMed

    Charter, M K; Gull, S F

    1991-10-01

    The application of maximum entropy to the calculation of drug absorption rates was introduced in an earlier paper. Here it is developed further, and the whole procedure is presented as a problem in scientific inference to be solved using Bayes' theorem. Blood samples do not need to be taken at equally spaced intervals, and no smoothing, interpolation, extrapolation, or other preprocessing of the data is necessary. The resulting input rate estimates are smooth and physiologically realistic, even with noisy data, and their accuracy is quantified. Derived quantities such as the proportion of the dose absorbed, and the mean and median absorption times, are also obtained, together with their error estimates. There are no arbitrarily valued parameters in the analysis, and no specific functional form, such as an exponential or polynomial, is assumed for the input rate functions. PMID:1783989

  7. Round window membrane intracochlear drug delivery enhanced by induced advection.

    PubMed

    Borkholder, David A; Zhu, Xiaoxia; Frisina, Robert D

    2014-01-28

    Delivery of therapeutic compounds to the inner ear via absorption through the round window membrane (RWM) has advantages over direct intracochlear infusions; specifically, minimizing impact upon functional hearing measures. However, previous reports show that significant basal-to-apical concentration gradients occur, with the potential to impact treatment efficacy. Here we present a new approach to inner ear drug delivery with induced advection aiding distribution of compounds throughout the inner ear in the murine cochlea. Polyimide microtubing was placed near the RWM niche through a bullaostomy into the middle ear cavity allowing directed delivery of compounds to the RWM. We hypothesized that a posterior semicircular canalostomy would induce apical flow from the patent cochlear aqueduct to the canalostomy due to influx of cerebral spinal fluid. To test this hypothesis, young adult CBA/CaJ mice were divided into two groups: bullaostomy approach only (BA) and bullaostomy+canalostomy (B+C). Cochlear function was evaluated by distortion product otoacoustic emission (DPOAE) and auditory brainstem response (ABR) thresholds during and after middle ear infusion of salicylate in artificial perilymph (AP), applied near the RWM. The mice recovered for 1week, and were re-tested. The results demonstrate there was no significant impact on auditory function utilizing the RWM surgical procedure with or without the canalostomy, and DPOAE thresholds were elevated reversibly during the salicylate infusion. Comparing the threshold shifts for both methods, the B+C approach had more of a physiological effect than the BA approach, including at lower frequencies representing more apical cochlear locations. Unlike mouse cochleostomies, there was no deleterious auditory functional impact after 1week recovery from surgery. The B+C approach had more drug efficacy at lower frequencies, underscoring potential benefits for more precise control of delivery of inner ear therapeutic compounds

  8. Round Window Membrane Intracochlear Drug Delivery Enhanced by Induced Advection

    PubMed Central

    Borkholder, David A.; Zhu, Xiaoxia; Frisina, Robert D.

    2014-01-01

    Delivery of therapeutic compounds to the inner ear via absorption through the round window membrane (RWM) has advantages over direct intracochlear infusions; specifically, minimizing impact upon functional hearing measures. However, previous reports show that significant basal-to-apical concentration gradients occur, with the potential to impact treatment efficacy. Here we present a new approach to inner ear drug delivery with induced advection aiding distribution of compounds throughout the inner ear in the murine cochlea. Polyimide microtubing was placed near the RWM niche through a bullaostomy into the middle ear cavity allowing directed delivery of compounds to the RWM. We hypothesized that a posterior semicircular canalostomy would induce apical flow from the patent cochlear aqueduct to the canalostomy due to influx of cerebral spinal fluid. To test this hypothesis, young adult CBA/CaJ mice were divided into two groups: bullaostomy approach only (BA) and bullaostomy + canalostomy (B+C). Cochlear function was evaluated by distortion product otoacoustic emission (DPOAE) and auditory brainstem response (ABR) thresholds during and after middle ear infusion of salicylate in artificial perilymph (AP), applied near the RWM. The mice recovered for 1 week, and were re-tested. The results demonstrate there was no significant impact on auditory function utilizing the RWM surgical procedure with or without the canalostomy, and DPOAE thresholds were elevated reversibly during the salicylate infusion. Comparing the threshold shifts for both methods, the B+C approach had more of a physiological effect than the BA approach, including at lower frequencies representing more apical cochlear locations. Unlike mouse cochleostomies, there was no deleterious auditory functional impact after 1 week recovery from surgery. The B+C approach had more drug efficacy at lower frequencies, underscoring potential benefits for more precise control of delivery of inner ear therapeutic compounds

  9. Conditions and drugs interfering with thyroxine absorption.

    PubMed

    Liwanpo, Llanyee; Hershman, Jerome M

    2009-12-01

    Food, dietary fibre and espresso coffee interfere with the absorption of levothyroxine. Malabsorptive disorders reported to affect the absorption of levothyroxine include coeliac disease, inflammatory bowel disease, lactose intolerance as well as Helicobacter pylori (H. pylori) infection and atrophic gastritis. Many commonly used drugs, such as bile acid sequestrants, ferrous sulphate, sucralfate, calcium carbonate, aluminium-containing antacids, phosphate binders, raloxifene and proton-pump inhibitors, have also been shown to interfere with the absorption of levothyroxine. PMID:19942153

  10. Water vapour foreign-continuum absorption in near-infrared windows from laboratory measurements.

    PubMed

    Ptashnik, Igor V; McPheat, Robert A; Shine, Keith P; Smith, Kevin M; Williams, R Gary

    2012-06-13

    For a long time, it has been believed that atmospheric absorption of radiation within wavelength regions of relatively high infrared transmittance (so-called 'windows') was dominated by the water vapour self-continuum, that is, spectrally smooth absorption caused by H(2)O--H(2)O pair interaction. Absorption due to the foreign continuum (i.e. caused mostly by H(2)O--N(2) bimolecular absorption in the Earth's atmosphere) was considered to be negligible in the windows. We report new retrievals of the water vapour foreign continuum from high-resolution laboratory measurements at temperatures between 350 and 430 K in four near-infrared windows between 1.1 and 5 μm (9000-2000 cm(-1)). Our results indicate that the foreign continuum in these windows has a very weak temperature dependence and is typically between one and two orders of magnitude stronger than that given in representations of the continuum currently used in many climate and weather prediction models. This indicates that absorption owing to the foreign continuum may be comparable to the self-continuum under atmospheric conditions in the investigated windows. The calculated global-average clear-sky atmospheric absorption of solar radiation is increased by approximately 0.46 W m(-2) (or 0.6% of the total clear-sky absorption) by using these new measurements when compared with calculations applying the widely used MTCKD (Mlawer-Tobin-Clough-Kneizys-Davies) foreign-continuum model. PMID:22547232

  11. PREDICTING DRUG DISPOSITION, ABSORPTION / ELIMINATION / TRANSPORTER INTERPLAY AND THE ROLE OF FOOD ON DRUG ABSORPTION

    PubMed Central

    Custodio, Joseph M.; Wu, Chi-Yuan; Benet, Leslie Z.

    2008-01-01

    The ability to predict drug disposition involves concurrent consideration of many chemical and physiological variables and the effect of food on the rate and extent of availability adds further complexity due to postprandial changes in the gastrointestinal (GI) tract. A system that allows for the assessment of the multivariate interplay occurring following administration of an oral dose, in the presence or absence of meal, would greatly benefit the early stages of drug development. This is particularly true in an era when the majority of new molecular entities are highly permeable, poorly soluble, extensively metabolized compounds (BDDCS Class 2), which present the most complicated relationship in defining the impact of transporters due to the marked effects of transporter-enzyme interplay. This review evaluates the GI luminal environment by taking into account the absorption / transport / elimination interplay and evaluates the physiochemical property issues by taking into account the importance of solubility, permeability and metabolism. We concentrate on the BDDCS and its utility in predicting drug disposition. Furthermore, we focus on the effect of food on the extent of drug availability (F), which appears to follow closely what might be expected if a significant effect of high fat meals is inhibition of transporters. That is, high fat meals and lipidic excipients would be expected to have little effect on F for Class 1 drugs; they would increase F of Class 2 drugs, while decreasing F for Class 3 drugs. PMID:18199522

  12. Added value of lung window in detecting drug mules on non-contrast abdominal computed tomography.

    PubMed

    Bahrami-Motlagh, Hooman; Vakilian, Fatemeh; Hassanian-Moghaddam, Hossein; Pourghorban, Ramin

    2016-06-01

    We evaluated the added value of lung window in non-contrast computed tomography (CT) of suspected body packers or stuffers. Forty suspected drug mules who were referred to our tertiary toxicology center were included. The final diagnosis of drug mule was based on the detection of packs in stool examination or surgery. Non-contrast CT scans were retrospectively interpreted by two blinded radiologists in consensus before and after reviewing the lung window images. The diagnostic performance of abdominal window scans alone and scans in both abdominal and lung windows were subsequently compared. Seven body packers and 21 body stuffers were identified. The sensitivity, negative predictive value (NPV), and diagnostic accuracy of scans in detection of drug mules (either drug packers or stuffers) raised from 60.7, 52.1, and 72.5 to 64.2, 54.5, and 75.0 %, respectively, with a more number of packs being detected (114 vs. 105 packs). In the body packers group, the diagnostic performance of both abdominal windows scans and combined abdominal and lung windows scans were 100 %. In the body stuffers group, the sensitivity, NPV, and diagnostic accuracy of scans increased from 47.6, 52.1, and 55.0 to 52.3, 54.5, and 57.5 %, respectively, after the addition of lung windows. Reviewing the lung window on non-contrast abdominal CT can be helpful in detection of drug mules. PMID:26830789

  13. Drug-resin drug interactions in patients with delayed gastric emptying: What is optimal time window for drug administration?

    PubMed

    Camilleri, M

    2016-08-01

    Most drug-drug interactions involve overlap or competition in drug metabolic pathways. However, there are medications, typically resins, whose function is to bind injurious substances such as bile acids or potassium within the digestive tract. The objective of this article is to review the functions of the stomach and the kinetics of emptying of different food forms or formulations to make recommendations on timing of medication administration in order to avoid intragastric drug interactions. Based on the profiles and kinetics of emptying of liquid nutrients and homogenized solids, a window of 3 h between administration of a resin drug and another 'target' medication would be expected to allow a median of 80% of medications with particle size <1 mm to empty from the stomach and, hence, avoid potential interaction such as binding of the 'target' medication within the stomach. PMID:26987693

  14. Chronic cranial window with access port for repeated cellular manipulations, drug application, and electrophysiology.

    PubMed

    Roome, Christopher J; Kuhn, Bernd

    2014-01-01

    Chronic cranial windows have been instrumental in advancing optical studies in vivo, permitting long-term, high-resolution imaging in various brain regions. However, once a window is attached it is difficult to regain access to the brain under the window for cellular manipulations. Here we describe a simple device that combines long term in vivo optical imaging with direct brain access via glass or quartz pipettes and metal, glass, or quartz electrodes for cellular manipulations like dye or drug injections and electrophysiological stimulations or recordings while keeping the craniotomy sterile. Our device comprises a regular cranial window glass coverslip with a drilled access hole later sealed with biocompatible silicone. This chronic cranial window with access port is cheap, easy to manufacture, can be mounted just as the regular chronic cranial window, and is self-sealing after retraction of the pipette or electrode. We demonstrate that multiple injections can be performed through the silicone port by repetitively bolus loading calcium sensitive dye into mouse barrel cortex and recording spontaneous cellular activity over a period of weeks. As an example to the extent of its utility for electrophysiological recording, we describe how simple removal of the silicone seal can permit patch pipette access for whole-cell patch clamp recordings in vivo. During these chronic experiments we do not observe any infections under the window or impairment of animal health. PMID:25426027

  15. Chronic cranial window with access port for repeated cellular manipulations, drug application, and electrophysiology

    PubMed Central

    Roome, Christopher J.; Kuhn, Bernd

    2014-01-01

    Chronic cranial windows have been instrumental in advancing optical studies in vivo, permitting long-term, high-resolution imaging in various brain regions. However, once a window is attached it is difficult to regain access to the brain under the window for cellular manipulations. Here we describe a simple device that combines long term in vivo optical imaging with direct brain access via glass or quartz pipettes and metal, glass, or quartz electrodes for cellular manipulations like dye or drug injections and electrophysiological stimulations or recordings while keeping the craniotomy sterile. Our device comprises a regular cranial window glass coverslip with a drilled access hole later sealed with biocompatible silicone. This chronic cranial window with access port is cheap, easy to manufacture, can be mounted just as the regular chronic cranial window, and is self-sealing after retraction of the pipette or electrode. We demonstrate that multiple injections can be performed through the silicone port by repetitively bolus loading calcium sensitive dye into mouse barrel cortex and recording spontaneous cellular activity over a period of weeks. As an example to the extent of its utility for electrophysiological recording, we describe how simple removal of the silicone seal can permit patch pipette access for whole-cell patch clamp recordings in vivo. During these chronic experiments we do not observe any infections under the window or impairment of animal health. PMID:25426027

  16. Absorption-Enhancing Effect of Nitric Oxide on the Absorption of Hydrophobic Drugs in Rat Duodenum.

    PubMed

    Kishimoto, Hisanao; Miyazaki, Kaori; Takizawa, Yusuke; Shirasaka, Yoshiyuki; Inoue, Katsuhisa

    2016-02-01

    Nitric oxide (NO), an endogenous gas that plays a versatile role in the physiological system, has the ability to increase the intestinal absorption of water-soluble compounds through the paracellular route. However, it remains unclear whether NO can enhance the absorption of hydrophobic drugs through the transcellular route. In this study, we examined the absorption-enhancing effect of NO on intestinal permeability of hydrophobic drugs in rat intestine. The pretreatment of rat gastrointestinal sacs with NOC7, a NO-releasing reagent, significantly increased the permeation of griseofulvin from mucosa to serosa in the sacs prepared from the duodenum, but not in those prepared from the other regions such as jejunum, ileum, and colon. The absorption-enhancing effect of NOC7 on the duodenal permeation varied depending on the hydrophobicity of the drugs used. Furthermore, NOC7 treatment was found to be apparently ineffective on the griseofulvin permeation in the duodenum pretreated with dithiothreitol (DTT) that was used as a mucus remover, even though the permeation was increased by pretreatment with DTT alone. These results suggest that NO increases the absorption of hydrophobic drugs through the transcellular route in the duodenum by modulating the mucus layer function. PMID:26458075

  17. Drug gastrointestinal absorption in rat: Strain and gender differences.

    PubMed

    Oltra-Noguera, Davinia; Mangas-Sanjuan, Victor; González-Álvarez, Isabel; Colon-Useche, Sarin; González-Álvarez, Marta; Bermejo, Marival

    2015-10-12

    Predictive animal models of intestinal drug absorption are essential tools in drug development to identify compounds with promising biopharmaceutical properties. In situ perfusion absorption studies are routinely used in the preclinical setting to screen drug candidates. The objective of this work is to explore the differences in magnitude and variability on intestinal absorption associated with rat strain and gender. Metoprolol and Verapamil absorption rate coefficients were determined using the in situ closed loop perfusion model in four strains of rats and in both genders. Strains used were Sprague-Dawley, Wistar-Han, Wistar-Unilever, Long-Evans and CD∗IGS. In the case of Metoprolol only CD∗IGS and Wistar Unilever showed differences between males and females. For Verapamil, Wistar Han and Sprague-Dawley strains do not show differences between male and female rats. That means that in these strains permeability data from male and female could be combined. In male rats, which are commonly used for permeability estimation, there were differences for Metoprolol permeability between Sprague-Dawley (with lower permeability values) and the other strains, while for Verapamil Sprague-Dawley and Wistar-Han showed the lower permeability values. In conclusion, the selection of rat's strain and gender for intestinal absorption experiments is a relevant element during study design and data from different strains may not be always comparable. PMID:26225436

  18. Neoadjuvant Window Studies of Metformin and Biomarker Development for Drugs Targeting Cancer Metabolism.

    PubMed

    Lord, Simon R; Patel, Neel; Liu, Dan; Fenwick, John; Gleeson, Fergus; Buffa, Francesca; Harris, Adrian L

    2015-05-01

    There has been growing interest in the potential of the altered metabolic state typical of cancer cells as a drug target. The antidiabetes drug, metformin, is now under intense investigation as a safe method to modify cancer metabolism. Several studies have used window of opportunity in breast cancer patients before neoadjuvant chemotherapy to correlate gene expression analysis, metabolomics, immunohistochemical markers, and metabolic serum markers with those likely to benefit. We review the role metabolite measurement, functional imaging and gene sequencing analysis play in elucidating the effects of metabolically targeted drugs in cancer treatment and determining patient selection. PMID:26063894

  19. Computational oral absorption simulation of free base drugs.

    PubMed

    Sugano, Kiyohiko

    2010-10-15

    The purpose of the present study was to investigate the oral absorption simulation of free base drugs. In the case of a low solubility free base drug, a portion of drug particles remains incompletely dissolved during the stomach transit and can reach the small intestine. As the pH is neutralized in the small intestine, the solubility of the drug decreases and the concentration gradient around the particles becomes a negative value. The drug particles would then grow because of this negative concentration gradient resulting in a reduction of the dissolved drug concentration. The modified Nernst Brunner equation was used to simulate both particle dissolution and growth (particle growth is the opposite phenomena of particle dissolution). Albendazole, aprepitant, dipyridamole, gefitinib and ketoconazole were used as model drugs (all free solid form (not salts)). The effect of stomach pH on oral absorption was appropriately simulated. Based on the simulation results, it was suggested that the dissolution patterns in the gastrointestinal tract were significantly different depending on the dose-solubility ratio in the stomach. PMID:20655999

  20. A diffusion-diffusion model for percutaneous drug absorption.

    PubMed

    Kubota, K; Ishizaki, T

    1986-08-01

    Several theories describing percutaneous drug absorption have been proposed, incorporating the mathematical solutions of differential equations describing percutaneous drug absorption processes where the vehicle and skin are regarded as simple diffusion membranes. By a solution derived from Laplace transforms, the mean residence time MRT and the variance of the residence time VRT in the vehicle are expressed as simple elementary functions of the following five pharmacokinetic parameters characterizing the percutaneous drug absorption: kd, which is defined as the normalized diffusion coefficient of the skin, kc, which is defined as the normalized skin-capillary boundary clearance, the apparent length of diffusion of the skin 1d, the effective length of the vehicle lv, and the diffusion coefficient of the vehicle Dv. All five parameters can be obtained by the methods proposed here. Results of numerical computation indicate that: concentration-distance curves in the vehicle and skin approximate two curves which are simply expressed using trigonometric functions when sufficient time elapses after an ointment application; the most suitable condition for the assumption that the concentration of a drug in the uppermost epidermis can be considered unchanged is the case where the partition coefficient between vehicle and skin is small, and the constancy of drug concentration is even more valid when the effective length of the vehicle is large; and the amount of a drug in the vehicle or skin and the flow rate of the drug from vehicle into skin or from skin into blood becomes linear on a semilogarithmic scale, and the slopes of those lines are small when Dv is small, when the partition coefficient between vehicle and skin is small, when lv is large, or when kc is small. A simple simulation method is also proposed using a biexponential for the concentration-time curve for the skin near the skin-capillary boundary, that is, the flow rate-time curve for drug passing from skin

  1. Vitamin, Mineral, and Drug Absorption Following Bariatric Surgery

    PubMed Central

    Sawaya, Ronald Andari; Jaffe, Jane; Friedenberg, Lindsay; Friedenberg, Frank K.

    2013-01-01

    The prevalence of obesity continues to rise throughout the world. Increasingly, bariatric surgery is used for those with morbid obesity as a pivotal approach to achieve weight loss. Along with substantial weight loss, malabsorption of essential vitamins, minerals, and drugs also occurs. Therefore, more than ever, a better understanding of the physiology and mechanisms by which these deficiencies occur is essential. We review the normal physiology of vitamin, mineral, and drug absorption. This is followed by a description of currently performed bariatric surgeries in the United States. A detailed review of specific nutrient and mineral deficiency states is presented, based on the most significant studies published in the last two decades. Of note, screening and supplementation recommendations have been included. Drug absorption data after these procedures is presented and discussed. Studies were identified by searching the Cochrane Registry and MEDLINE using relevant search terms, as well as through review of the reference section of included manuscripts. Conclusions Bariatric surgery can be effectively used to achieve sustainable weight-loss in morbidly obese patients. It simultaneously brings forth important functional consequences on nutrient deficiencies and drug absorption that clinician’s must be aware of. Further prospective, randomized research on specific procedures and deficiencies is required. PMID:22746302

  2. In Silico Modeling of Gastrointestinal Drug Absorption: Predictive Performance of Three Physiologically Based Absorption Models.

    PubMed

    Sjögren, Erik; Thörn, Helena; Tannergren, Christer

    2016-06-01

    Gastrointestinal (GI) drug absorption is a complex process determined by formulation, physicochemical and biopharmaceutical factors, and GI physiology. Physiologically based in silico absorption models have emerged as a widely used and promising supplement to traditional in vitro assays and preclinical in vivo studies. However, there remains a lack of comparative studies between different models. The aim of this study was to explore the strengths and limitations of the in silico absorption models Simcyp 13.1, GastroPlus 8.0, and GI-Sim 4.1, with respect to their performance in predicting human intestinal drug absorption. This was achieved by adopting an a priori modeling approach and using well-defined input data for 12 drugs associated with incomplete GI absorption and related challenges in predicting the extent of absorption. This approach better mimics the real situation during formulation development where predictive in silico models would be beneficial. Plasma concentration-time profiles for 44 oral drug administrations were calculated by convolution of model-predicted absorption-time profiles and reported pharmacokinetic parameters. Model performance was evaluated by comparing the predicted plasma concentration-time profiles, Cmax, tmax, and exposure (AUC) with observations from clinical studies. The overall prediction accuracies for AUC, given as the absolute average fold error (AAFE) values, were 2.2, 1.6, and 1.3 for Simcyp, GastroPlus, and GI-Sim, respectively. The corresponding AAFE values for Cmax were 2.2, 1.6, and 1.3, respectively, and those for tmax were 1.7, 1.5, and 1.4, respectively. Simcyp was associated with underprediction of AUC and Cmax; the accuracy decreased with decreasing predicted fabs. A tendency for underprediction was also observed for GastroPlus, but there was no correlation with predicted fabs. There were no obvious trends for over- or underprediction for GI-Sim. The models performed similarly in capturing dependencies on dose and

  3. Canine gastrointestinal physiology: Breeds variations that can influence drug absorption.

    PubMed

    Oswald, Hayley; Sharkey, Michele; Pade, Devendra; Martinez, Marilyn N

    2015-11-01

    Although all dogs belong to Canis lupus familiaris, the physiological diversity resulting from selective breeding can lead to wide interbreed variability in drug pharmacokinetics (PK) or in oral drug product performance. It is important to understand this diversity in order to predict the impact of drug product formulation attributes on in vivo dissolution and absorption characteristics across the canine population when the dog represents the targeted patient population. Based upon published information, this review addresses breed differences in gastrointestinal (GI) physiology and discusses the in vivo implications of these differences. In addition to the importance of such information for understanding the variability that may exist in the performance of oral dosage forms in dogs for the purpose of developing canine therapeutics, an appreciation of breed differences in GI physiology can improve our prediction of oral drug formulation performance when we extrapolate bioavailability results from the dog to the humans, and vice versa. In this literature review, we examine reports of breed associated diversity in GI anatomy and morphology, gastric emptying time (GET), oro-cecal transit time (OCTT), small intestinal transit time (SITT), large intestinal transit time (LITT), intestinal permeability, sodium/potassium fecal concentrations, intestinal flora, and fecal moisture content. PMID:26409436

  4. Minimally invasive drug delivery to the cochlea through application of nanoparticles to the round window membrane.

    PubMed

    Buckiová, Daniela; Ranjan, Sanjeev; Newman, Tracey A; Johnston, Alexander H; Sood, Rohit; Kinnunen, Paavo K J; Popelář, Jiří; Chumak, Tetyana; Syka, Josef

    2012-09-01

    Direct drug delivery to the cochlea is associated with the risk of irreversible damage to the ear. In this study, liposome and polymersome nanoparticles (NPs), both formed from amphiphilic molecules (lipids in liposomes and block copolymers in polymersomes), were tested as potential tools for drug delivery to the cochlea via application onto the round window membrane in adult mice (strain C3H). One day after round window membrane application, both types of NPs labeled with fluorescent markers were identified in the spiral ganglion in all cochlear turns without producing any distinct morphological or functional damage to the inner ear. NPs were detected, although to a lesser extent, in the organ of Corti and the lateral wall. The potential of liposome and polymersome NPs as therapeutic delivery systems into the cochlea via the round window membrane was evaluated using disulfiram, a neurotoxic agent, as a model payload. Disulfiram-loaded NP delivery resulted in a significant decrease in the number of spiral ganglion cells starting 2 days postapplication, with associated pronounced hearing loss reaching 20-35 dB 2 weeks postapplication as assessed through auditory brainstem responses. No changes in hair cell morphology and function (as assessed by recording otoacoustic emissions) were detected after disulfiram-loaded NP application. No effects were observed in controls where solution of free disulfiram was similarly administered. The results demonstrate that liposome and polymersome NPs are capable of carrying a payload into the inner ear that elicits a biological effect, with consequences measurable by a functional readout. PMID:22475648

  5. Quantitation of small intestinal permeability during normal human drug absorption

    PubMed Central

    2013-01-01

    Background Understanding the quantitative relationship between a drug’s physical chemical properties and its rate of intestinal absorption (QSAR) is critical for selecting candidate drugs. Because of limited experimental human small intestinal permeability data, approximate surrogates such as the fraction absorbed or Caco-2 permeability are used, both of which have limitations. Methods Given the blood concentration following an oral and intravenous dose, the time course of intestinal absorption in humans was determined by deconvolution and related to the intestinal permeability by the use of a new 3 parameter model function (“Averaged Model” (AM)). The theoretical validity of this AM model was evaluated by comparing it to the standard diffusion-convection model (DC). This analysis was applied to 90 drugs using previously published data. Only drugs that were administered in oral solution form to fasting subjects were considered so that the rate of gastric emptying was approximately known. All the calculations are carried out using the freely available routine PKQuest Java (http://www.pkquest.com) which has an easy to use, simple interface. Results Theoretically, the AM permeability provides an accurate estimate of the intestinal DC permeability for solutes whose absorption ranges from 1% to 99%. The experimental human AM permeabilities determined by deconvolution are similar to those determined by direct human jejunal perfusion. The small intestinal pH varies with position and the results are interpreted in terms of the pH dependent octanol partition. The permeability versus partition relations are presented separately for the uncharged, basic, acidic and charged solutes. The small uncharged solutes caffeine, acetaminophen and antipyrine have very high permeabilities (about 20 x 10-4 cm/sec) corresponding to an unstirred layer of only 45 μm. The weak acid aspirin also has a large AM permeability despite its low octanol partition at pH 7.4, suggesting

  6. Influence of drug physicochemical properties on absorption of water insoluble drug nanosuspensions.

    PubMed

    Li, Wei; Quan, Peng; Zhang, Yaqiong; Cheng, Jing; Liu, Jie; Cun, Dongmei; Xiang, Rongwu; Fang, Liang

    2014-01-01

    In order to investigate the influence of drug physicochemical properties on bioavailability of water insoluble drug nanosuspensions, five drug nanosuspensions were prepared using high pressure homogenization. These nanosuspensions were similar in particle size and same in stabilizer. Differential scanning calorimetry and powder X-ray diffraction analysis showed the crystalline state of the freeze dried nanocrystals did not change. In vitro dissolution test in fasted state simulated intestinal fluid (FaSSIF) and in vivo bioavailability study in rats demonstrated that the nanosuspensions had higher dissolution rate and higher AUC0-t and the ratios of dissolvednano/dissolvedmicro in 120 min were well correlated with the ratios of AUC0-t nano/AUC0-t micro. Correlation analysis between drug physicochemical properties and AUC0-t nano was performed and four-grid interpolation method was employed for interpolation and smooth surface fitting to give a visible trend. The results revealed that drug with smaller melting point, logP value around 5 and polar surface area value in the range of 50-60 would gain higher AUC0-t nano and accordingly better absorption of its nanosuspension. Melting point, logP and polar surface area were factors that influence the absorption of drug nanosuspensions in this study. PMID:24184036

  7. Evaluation wavelength range mapping, a tool to optimize the evaluation window in differential absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Vogel, L.; Sihler, H.; Lampel, J.; Wagner, T.; Platt, U.

    2012-04-01

    Optical remote sensing via Differential Optical Absorption Spectroscopy (DOAS) has become a standard technique to assess various trace gases in the atmosphere. Measurement instruments are usually classified into active instruments applying an artificial light source and passive instruments using natural light sources, e.g., scattered or direct sunlight. Platforms range from ground based to satellites and trace gases are studied in all kinds of different environments. Naturally, the evaluation of gathered spectra needs to be tuned to each specific case and trace gas of interest due to the wide range of measurement conditions, atmospheric compositions and instruments used. A well chosen evaluation wavelength range is crucial to the DOAS technique. It should be as large as possible and include the largest differential absorption features of the trace gas of interest in order to maximize sensitivity. However, the differential optical densities of other absorbers should be minimized in order to prevent interferences between different absorption cross sections. Furthermore, instrumental specific features and wavelength dependent radiative transfer effects may have malicious effects and lead to erroneous values. Usually a compromise needs to be found depending on the conditions at hand. Evaluation wavelength range mapping is an easily applied tool to visualize wavelength depending evaluation features of DOAS and to find the optimal retrieval wavelength range. As an example, synthetic spectra are studied which simulate passive DOAS measurements of stratospheric bromine monoxide (BrO) by Zenith-DOAS and Multi-Axis DOAS (MAX-DOAS) measurements of BrO in volcanic plumes. The influence of the I0-effect and the Ring-effect on the respective retrievals are demonstrated. However, due to the general nature of the tool it is applicable to any DOAS measurement and the technique also allows to study any other wavelength dependent influences on retrieved trace gas columns.

  8. Modular Simulation of Absorption Systems User's Guide (Windows Version 5.0)

    SciTech Connect

    Grossman, G

    2000-09-25

    ABSIM (an acronym for ABsorption SIMulation) is a user-oriented computer code designed for the simulation of absorption systems at steady state, in both flexible and modular form. ABSIM makes it possible to investigate various cycle configurations with different working fluids, to calculate their operating parameters, to predict their performance and to compare them with each other on a uniform basis. A graphical user interface enables the user to draw the cycle diagram on the computer screen, enter data interactively, run the program and view the results either in the form of a table or superimposed on the cycle diagram. Special utilities enable the user to plot the results and produce a pressure-temperature-concentration (P-T-X) diagram of the cycle. Most absorption systems consist of a number of standard components or units (e.g., absorber, condenser) that may be combined in different forms to produce various cycles. Recognizing this, ABSIM has been structured around unit subroutines, each of which contains the governing equations for the particular unit. These subroutines are activated by a main program that interprets the input for the cycle, calls the units, and links them to each other in an order corresponding to the user's specification to form the complete system. Each unit subroutine, when activated, addresses a property database for the thermodynamic properties of the working fluids. The equations generated by the code are listed and solved simultaneously by a mathematical solver routine. The code requires relatively simple inputs, consisting of the minimum information needed to define an absorption system properly. After drawing the cycle in terms of the units recognizable by the code and showing their interconnections, the user must specify the size of each exchange unit in terms of its heat and mass transfer characteristics, the working fluid(s) at each state point; and the given operating conditions, such as temperatures, flowrates, and the like

  9. Long-pathlength infrared absorption measurements in the 8- to 14-{mu}m atmospheric window: Self-broadening coefficient data

    SciTech Connect

    Kulp, T.J.; Shinn, J.

    1995-04-01

    The accurate characterization of the latent infrared (IR) absorption in the atmospheric window regions continues to be an area of research interest for the global climate modeling community. In the window between 8 and 14 {mu}m, this absorption can be attributed primarily to water vapor. It consists of (1) weak lines originating from the edge of the water vapor pure rotational band (at low wavenumbers) and the trailing P-branch of the v{sub 2} rovibrational band (at the high-wavenumber boundary of the window); and (2) the water vapor continuum absorption. The goal of our project has been to improve our quantitative and physical understanding of both of these absorption processes. Specifically, our immediate aims are to fill gaps in the experimental radiative transfer databases pertaining to the line parameters (i.e., line intensities and broadening coefficients) and to the self- and foreign-broadened water vapor continuum. To accomplish our goals, we have made long-pathlength absorption measurements using a Fourier transform infrared spectrometer (FTIR) (for the continuum and line measurements, at low resolution) and a tunable diode laser absorption spectrometer (TDLAS) (for the line measurements, at high resolution). These measurements were made on gas samples contained in a 400-m maximum pathlength Horn Pimentel multipass cell designed and constructed for this project.

  10. Constant optimization of oral drug absorption kinetics in the compartment absorption and transit models using particle swarm optimization algorithm

    NASA Astrophysics Data System (ADS)

    Prabowo, K.; Sumaryada, T.; Kartono, A.

    2016-01-01

    Simulation of predictive modeling oral drug namely Compartment Absorption and Transit (CAT) using Particle Swarm Optimization (PSO) algorithm has been performed. This research will be carried out optimization of kinetic constant value oral drug use PSO algorithm to obtain the best global transport constant values for CAT equation that can predict drug concentration in plasma. The value of drug absorption rate constant for drug atenolol 25 mg is k10, k12, k21, k13 and k31 with each value is 0.8562, 0.3736, 0.2191, 0.4334 and 1.000 have been obtained thus raising the value of the coefficient of determination of a model CAT. From the experimental data plasma drug concentrations used are Atenolol, the coefficient of determination (R2) obtained from simulations atenolol 25 mg (PSO) was 81.72% and 99.46%. Better correlation between the dependent variable as the drug concentration and explanatory variables such as mass medication, plasma volume, and rate of absorption of the drug has increased in CAT models using PSO algorithm. Based on the results of CAT models fit charts can predict drug concentration in plasma.

  11. Absorption-enhancing effects of gemini surfactant on the intestinal absorption of poorly absorbed hydrophilic drugs including peptide and protein drugs in rats.

    PubMed

    Alama, Tammam; Kusamori, Kosuke; Katsumi, Hidemasa; Sakane, Toshiyasu; Yamamoto, Akira

    2016-02-29

    In general, the intestinal absorption of small hydrophilic molecules and macromolecules like peptides, after oral administration is very poor. Absorption enhancers are considered to be one of the most promising agents to enhance the intestinal absorption of drugs. In this research, we focused on a gemini surfactant, a new type of absorption enhancer. The intestinal absorption of drugs, with or without sodium dilauramidoglutamide lysine (SLG-30), a gemini surfactant, was examined by an in situ closed-loop method in rats. The intestinal absorption of 5(6)-carboxyfluorescein (CF) and fluorescein isothiocyanate-dextrans (FDs) was significantly enhanced in the presence of SLG-30, such effect being reversible. Furthermore, the calcium levels in the plasma significantly decreased when calcitonin was co-administered with SLG-30, suggestive of the increased intestinal absorption of calcitonin. In addition, no significant increase in the of lactate dehydrogenase (LDH) activity or in protein release from the intestinal epithelium was observed in the presence of SLG-30, suggestive of the safety of this compound. These findings indicate that SLG-30 is an effective absorption-enhancer for improving the intestinal absorption of poorly absorbed drugs, without causing serious damage to the intestinal epithelium. PMID:26707414

  12. Determination of drug permeability and prediction of drug absorption in Caco-2 monolayers.

    PubMed

    Hubatsch, Ina; Ragnarsson, Eva G E; Artursson, Per

    2007-01-01

    Permeability coefficients across monolayers of the human colon carcinoma cell line Caco-2, cultured on permeable supports, are commonly used to predict the absorption of orally administered drugs and other xenobiotics. This protocol describes our method for the cultivation, characterization and determination of permeability coefficients of xenobiotics (which are, typically, drug-like compounds) in the Caco-2 model. A few modifications that have been introduced over the years are incorporated in the protocol. The method can be used to trace the permeability of a test compound in two directions, from the apical to the basolateral side or vice versa, and both passive and active transport processes can be studied. The permeability assay can be completed within one working day, provided that the Caco-2 monolayers have been cultured and differentiated on the permeable supports 3 weeks in advance. PMID:17853866

  13. Application of Physiologically Based Absorption Modeling for Amphetamine Salts Drug Products in Generic Drug Evaluation.

    PubMed

    Babiskin, Andrew H; Zhang, Xinyuan

    2015-09-01

    Amphetamine (AMP) salts-based extended-release (ER) drug products are widely used for the treatment of attention deficit hyperactivity disorder. We developed physiologically based absorption models for mixed AMP salts ER capsules and dextroamphetamine sulfate ER capsules to address specific questions raised during generic drug postmarketing surveillance and bioequivalence (BE) guidance development. The models were verified against several data sets. Virtual BE simulations were conducted to assess BE in various populations other than normal healthy subjects where BE studies are generally conducted for approval. The models were also used to predict pharmacokinetics (PK) for hypothetical formulations having dissolution profiles falling within specification after the development of in vitro-in vivo relation. Finally, we demonstrated how to use the models to test sensitivity of PK metrics to the changes in formulation variables. PMID:25973928

  14. Ultra-fast absorption of amorphous pure drug aerosols via deep lung inhalation.

    PubMed

    Rabinowitz, Joshua D; Lloyd, Peter M; Munzar, Patrik; Myers, Daniel J; Cross, Steve; Damani, Ramesh; Quintana, Reynaldo; Spyker, Daniel A; Soni, Pravin; Cassella, James V

    2006-11-01

    A deficiency of most current drug products for treatment of acute conditions is slow onset of action. A promising means of accelerating drug action is through rapid systemic drug administration via deep lung inhalation. The speed of pulmonary drug absorption depends on the site of aerosol deposition within the lung and the dissolution rate and drug content of the deposited particles. Alveolar delivery of fast-dissolving, pure drug particles should in theory enable very rapid absorption. We have previously shown that heating of thin drug films generates vapor-phase drug that subsequently cools and condenses into pure drug particles of optimal size for alveolar delivery. Here we present a hand held, disposable, breath-actuated device incorporating this thermal aerosol technology, and its application to the delivery of alprazolam, an anti-panic agent, and prochlorperazine, an anti-emetic with recently discovered anti-migraine properties. Thermal aerosol particles of these drugs exist in an amorphous state, which results in remarkably rapid drug absorption from the lung into the systemic circulation, with peak left ventricular concentrations achieved within 20 s, even quicker than following rapid (5 s) intravenous infusion. Absorption of the thermal aerosol is nearly complete, with >80% absolute bioavailability found in both dogs and human normal volunteers. PMID:16886198

  15. On the absorption of drugs using chronic dog ileal loop method.

    PubMed

    Kukan, M; Bezek, S; Trnovec, T; Gabauer, I; Styk, J

    1994-01-01

    The absorption rate of three model drugs, i.e., pentacaine (highly lipophilic), stobadine (moderately lipophilic) and acetylsalicylic acid (hydrophilic), was studied using the chronic dog ileal loop method. The drugs were dissolved either in 0.9% unbuffered solution of NaCl or in antacid mixture. When using 0.9% NaCl, the half-lives of absorption (t1/2 (dis)) of pentacaine and stobadine were (mean +/- SD) 23.2 +/- 7.8 min and 20.8 +/- 7.2 min, respectively. For stobadine a good agreement was found between its t1/2 (dis) from the ileum and its absorption half-life determined from blood concentrations after oral administration to dogs. The absorption of acetylsalicylic acid accounted for only 10-20% of the dose introduced into the loop over 45 min; thus, a reliable value of t1/2 (dis) could not be determined. The administration of unbuffered solution of NaCl into the loop was accompanied by rapid increase of pH from acidic to basic value. The antacid mixture failed to affect the absorption rate of the drugs studied. Sampling from the ileum was limited to 35-55 min due to rapid absorption of water. These results suggest that: 1) measurement of the absorption rate of some drugs, e.g., stobadine, by using the chronic dog ileal loop method may adequately predict their absorption rate after peroral administration to the dog, 2) interactions of antacids with drug absorption in the ileum may not play a significant role because of the strong buffering capacity of the ileum, and 3) rapid absorption of water from the ileum does not allow to reliably determine the value of t1/2 (dis) for slowly absorbed drugs. PMID:7837833

  16. In silico predictions of gastrointestinal drug absorption in pharmaceutical product development: application of the mechanistic absorption model GI-Sim.

    PubMed

    Sjögren, Erik; Westergren, Jan; Grant, Iain; Hanisch, Gunilla; Lindfors, Lennart; Lennernäs, Hans; Abrahamsson, Bertil; Tannergren, Christer

    2013-07-16

    Oral drug delivery is the predominant administration route for a major part of the pharmaceutical products used worldwide. Further understanding and improvement of gastrointestinal drug absorption predictions is currently a highly prioritized area of research within the pharmaceutical industry. The fraction absorbed (fabs) of an oral dose after administration of a solid dosage form is a key parameter in the estimation of the in vivo performance of an orally administrated drug formulation. This study discloses an evaluation of the predictive performance of the mechanistic physiologically based absorption model GI-Sim. GI-Sim deploys a compartmental gastrointestinal absorption and transit model as well as algorithms describing permeability, dissolution rate, salt effects, partitioning into micelles, particle and micelle drifting in the aqueous boundary layer, particle growth and amorphous or crystalline precipitation. Twelve APIs with reported or expected absorption limitations in humans, due to permeability, dissolution and/or solubility, were investigated. Predictions of the intestinal absorption for different doses and formulations were performed based on physicochemical and biopharmaceutical properties, such as solubility in buffer and simulated intestinal fluid, molecular weight, pK(a), diffusivity and molecule density, measured or estimated human effective permeability and particle size distribution. The performance of GI-Sim was evaluated by comparing predicted plasma concentration-time profiles along with oral pharmacokinetic parameters originating from clinical studies in healthy individuals. The capability of GI-Sim to correctly predict impact of dose and particle size as well as the in vivo performance of nanoformulations was also investigated. The overall predictive performance of GI-Sim was good as >95% of the predicted pharmacokinetic parameters (C(max) and AUC) were within a 2-fold deviation from the clinical observations and the predicted plasma AUC

  17. Developments in Methods for Measuring the Intestinal Absorption of Nanoparticle-Bound Drugs.

    PubMed

    Liu, Wei; Pan, Hao; Zhang, Caiyun; Zhao, Liling; Zhao, Ruixia; Zhu, Yongtao; Pan, Weisan

    2016-01-01

    With the rapid development of nanotechnology, novel drug delivery systems comprising orally administered nanoparticles (NPs) have been paid increasing attention in recent years. The bioavailability of orally administered drugs has significant influence on drug efficacy and therapeutic dosage, and it is therefore imperative that the intestinal absorption of oral NPs be investigated. This review examines the various literature on the oral absorption of polymeric NPs, and provides an overview of the intestinal absorption models that have been developed for the study of oral nanoparticles. Three major categories of models including a total of eight measurement methods are described in detail (in vitro: dialysis bag, rat gut sac, Ussing chamber, cell culture model; in situ: intestinal perfusion, intestinal loops, intestinal vascular cannulation; in vivo: the blood/urine drug concentration method), and the advantages and disadvantages of each method are contrasted and elucidated. In general, in vitro and in situ methods are relatively convenient but lack accuracy, while the in vivo method is troublesome but can provide a true reflection of drug absorption in vivo. This review summarizes the development of intestinal absorption experiments in recent years and provides a reference for the systematic study of the intestinal absorption of nanoparticle-bound drugs. PMID:27455239

  18. Developments in Methods for Measuring the Intestinal Absorption of Nanoparticle-Bound Drugs

    PubMed Central

    Liu, Wei; Pan, Hao; Zhang, Caiyun; Zhao, Liling; Zhao, Ruixia; Zhu, Yongtao; Pan, Weisan

    2016-01-01

    With the rapid development of nanotechnology, novel drug delivery systems comprising orally administered nanoparticles (NPs) have been paid increasing attention in recent years. The bioavailability of orally administered drugs has significant influence on drug efficacy and therapeutic dosage, and it is therefore imperative that the intestinal absorption of oral NPs be investigated. This review examines the various literature on the oral absorption of polymeric NPs, and provides an overview of the intestinal absorption models that have been developed for the study of oral nanoparticles. Three major categories of models including a total of eight measurement methods are described in detail (in vitro: dialysis bag, rat gut sac, Ussing chamber, cell culture model; in situ: intestinal perfusion, intestinal loops, intestinal vascular cannulation; in vivo: the blood/urine drug concentration method), and the advantages and disadvantages of each method are contrasted and elucidated. In general, in vitro and in situ methods are relatively convenient but lack accuracy, while the in vivo method is troublesome but can provide a true reflection of drug absorption in vivo. This review summarizes the development of intestinal absorption experiments in recent years and provides a reference for the systematic study of the intestinal absorption of nanoparticle-bound drugs. PMID:27455239

  19. Comparison of activated charcoal and ipecac syrup in prevention of drug absorption.

    PubMed

    Neuvonen, P J; Vartiainen, M; Tokola, O

    1983-01-01

    The efficacy of activated charcoal and ipecac syrup in the prevention of drug absorption was studied in 6 healthy adult volunteers, using a randomized, cross-over design. Paracetamol 1000 mg, tetracycline 500 mg and aminophylline 350 mg were ingested on an empty stomach with 100 ml water. Then, after 5 or 30 min, the subjects ingested, either activated charcoal suspension (50 g charcoal), syrup of ipecac, or, only after 5 min, water 300 ml. Activated charcoal, given either after 5 or 30 min, significantly (p less than 0.01 or less 0.05) reduced the absorption of these 3 drugs measured, for example as AUC0-24 h. Syrup of ipecac caused emesis on each occasion, with a mean delay of 15 min. When ipecac was given 5 min after the drugs, its effect on absorption was significant, but when it was given after 30 min only the absorption of tetracycline was reduced. Activated charcoal was significantly (p less than 0.05) more effective than ipecac in reducing drug absorption when given at the same time points. In cases of acute intoxication, depending on the quality and quantity of the drugs ingested, the relative efficacy of charcoal and ipecac may be somewhat different from that observed in the present study. Despite its emetic action, however, ipecac syrup is not very effective in preventing drug absorption and, in general, activated charcoal should also be given after induced emesis or gastric lavage. PMID:6134626

  20. Novel flower-shaped albumin particles as controlled-release carriers for drugs to penetrate the round-window membrane

    PubMed Central

    Yu, Zhan; Yu, Min; Zhou, Zhimin; Zhang, Zhibao; Du, Bo; Xiong, Qingqing

    2014-01-01

    Controlled-release carriers for local drug delivery have attracted increasing attention for inner-ear treatment recently. In this paper, flower-shaped bovine serum albumin (FBSA) particles were prepared by a modified desolvation method followed by glutaraldehyde or heat denaturation. The size of the FBSA particles varied from 10 μm to 100 μm, and most were 50–80 μm. Heat-denatured FBSA particles have good cytocompatibility with a prolonged survival time for L929 cells. The FBSA particles were utilized as carriers to investigate the release behaviors of the model drug – rhodamine B. Rhodamine B showed a sustained-release effect and penetrated the round-window membrane of guinea pigs. We also confirmed the attachment of FBSA particles onto the round-window membrane by microscopy. The FBSA particles, with good biocompatibility, drug-loading capacity, adhesive capability, and biodegradability, may have potential applications in the field of local drug delivery for inner-ear disease treatment. PMID:25061296

  1. A mechanistic approach to understanding oral drug absorption in pediatrics: an overview of fundamentals.

    PubMed

    Debotton, Nir; Dahan, Arik

    2014-09-01

    The common phrase 'children are not little adults' is very true also in the field of oral drug administration and absorption. However, in practice, due to the little available data and lack of in-depth understanding, physicians may treat kids as if they were 'little adults', even without being aware of the potential differences and risks. With respect to drug discovery, research and development, an in-depth understanding of the various factors governing age-dependent absorption is crucial when trying to develop a pediatric-tailored oral drug product. In this paper we clarify the various mechanisms that may lead to age-dependent oral drug absorption, we provide an overview of the currently available data, and draw conclusions to the coming years. PMID:24846709

  2. Accurate measurements and temperature dependence of the water vapor self-continuum absorption in the 2.1 μm atmospheric window.

    PubMed

    Ventrillard, I; Romanini, D; Mondelain, D; Campargue, A

    2015-10-01

    In spite of its importance for the evaluation of the Earth radiative budget, thus for climate change, very few measurements of the water vapor continuum are available in the near infrared atmospheric windows especially at temperature conditions relevant for our atmosphere. In addition, as a result of the difficulty to measure weak broadband absorption signals, the few available measurements show large disagreements. We report here accurate measurements of the water vapor self-continuum absorption in the 2.1 μm window by Optical Feedback Cavity Enhanced Absorption Spectroscopy (OF-CEAS) for two spectral points located at the low energy edge and at the center of the 2.1 μm transparency window, at 4302 and 4723 cm(-1), respectively. Self-continuum cross sections, CS, were retrieved with a few % relative uncertainty, from the quadratic dependence of the spectrum base line level measured as a function of water vapor pressure, between 0 and 16 Torr. At 296 K, the CS value at 4302 cm(-1) is found 40% higher than predicted by the MT_CKD V2.5 model, while at 4723 cm(-1), our value is 5 times larger than the MT_CKD value. On the other hand, these OF-CEAS CS values are significantly smaller than recent measurements by Fourier transform spectroscopy at room temperature. The temperature dependence of the self-continuum cross sections was also investigated for temperatures between 296 K and 323 K (23-50 °C). The derived temperature variation is found to be similar to that derived from previous Fourier transform spectrometer (FTS) measurements performed at higher temperatures, between 350 K and 472 K. The whole set of measurements spanning the 296-472 K temperature range follows a simple exponential law in 1/T with a slope close to the dissociation energy of the water dimer, D0 ≈ 1100 cm(-1). PMID:26450311

  3. Application of xCELLigence RTCA Biosensor Technology for Revealing the Profile and Window of Drug Responsiveness in Real Time.

    PubMed

    Kho, Dan; MacDonald, Christa; Johnson, Rebecca; Unsworth, Charles P; O'Carroll, Simon J; du Mez, Elyce; Angel, Catherine E; Graham, E Scott

    2015-06-01

    The xCELLigence technology is a real-time cellular biosensor, which measures the net adhesion of cells to high-density gold electrode arrays printed on custom-designed E-plates. The strength of cellular adhesion is influenced by a myriad of factors that include cell type, cell viability, growth, migration, spreading and proliferation. We therefore hypothesised that xCELLigence biosensor technology would provide a valuable platform for the measurement of drug responses in a multitude of different experimental, clinical or pharmacological contexts. In this manuscript, we demonstrate how xCELLigence technology has been invaluable in the identification of (1) not only if cells respond to a particular drug, but (2) the window of drug responsiveness. The latter aspect is often left to educated guess work in classical end-point assays, whereas biosensor technology reveals the temporal profile of the response in real time, which enables both acute responses and longer term responses to be profiled within the same assay. In our experience, the xCELLigence biosensor technology is suitable for highly targeted drug assessment and also low to medium throughput drug screening, which produces high content temporal data in real time. PMID:25893878

  4. Application of xCELLigence RTCA Biosensor Technology for Revealing the Profile and Window of Drug Responsiveness in Real Time

    PubMed Central

    Kho, Dan; MacDonald, Christa; Johnson, Rebecca; Unsworth, Charles P.; O’Carroll, Simon J.; du Mez, Elyce; Angel, Catherine E.; Graham, E. Scott

    2015-01-01

    The xCELLigence technology is a real-time cellular biosensor, which measures the net adhesion of cells to high-density gold electrode arrays printed on custom-designed E-plates. The strength of cellular adhesion is influenced by a myriad of factors that include cell type, cell viability, growth, migration, spreading and proliferation. We therefore hypothesised that xCELLigence biosensor technology would provide a valuable platform for the measurement of drug responses in a multitude of different experimental, clinical or pharmacological contexts. In this manuscript, we demonstrate how xCELLigence technology has been invaluable in the identification of (1) not only if cells respond to a particular drug, but (2) the window of drug responsiveness. The latter aspect is often left to educated guess work in classical end-point assays, whereas biosensor technology reveals the temporal profile of the response in real time, which enables both acute responses and longer term responses to be profiled within the same assay. In our experience, the xCELLigence biosensor technology is suitable for highly targeted drug assessment and also low to medium throughput drug screening, which produces high content temporal data in real time. PMID:25893878

  5. Understanding Disease-Drug Interactions in Cancer Patients: Implications for Dosing Within the Therapeutic Window.

    PubMed

    Coutant, D E; Kulanthaivel, P; Turner, P K; Bell, R L; Baldwin, J; Wijayawardana, S R; Pitou, C; Hall, S D

    2015-07-01

    The human inflammatory response can result in the alteration of drug clearance through effects on metabolizing enzymes or transporters. In this article we briefly review the theory of how cancer can lead to indirect changes in drug metabolism, review acute phase proteins and cytokines as markers of changes in cytochrome P450 (CYP) activity in cancer patients, and provide clinical case examples of how the inflammation in advanced cancer patients can lead to altered CYP-mediated drug clearance. PMID:25808023

  6. Enhancing drugs absorption through third-degree burn wound eschar.

    PubMed

    Manafi, Ali; Hashemlou, Azadeh; Momeni, Parisa; Moghimi, Hamid R

    2008-08-01

    Antimicrobial therapy remains the most important method of wound infection treatment. Systemically administered antimicrobials may not achieve therapeutic levels in wound. On the other hand, some topically applied antimicrobials cannot penetrate eschar well enough. Therefore, an attempt has been made here to increase permeation of topically applied drugs through eschar using the so-called skin penetration enhancers. To perform this investigation, effects of different potential penetration enhancers on permeation of chlorhexidine, silver sulfadiazine and nitroglycerin through human third-degree burn eschar was evaluated. Results showed that water, glycerin, saline, sodium lauryl sulphate (SDS) and ethanol tend to reduce permeation of chlorhexidine through burn eschar. But, water, glycerin, hexane:ethanol and ethyl acetate:ethanol were able to increase permeation of silver sulfadiazine significantly by about 1.2-1.8 times, while saline, SDS and dimethyl sulfoxide were not able to change its permeation. Glycine showed 2.7 times enhancement toward permeation of nitroglycerin, followed by water, hexane:ethanol mixture, saline and SDS with enhancement ratios of 1.8-2.3. Urea, ethanol and citral were not able to increase permeation of nitroglycerin through eschar. This study shows that permeation of drugs through burn eschar can be improved by penetration enhancement including hydration; the effect depends on the nature of the penetrant. PMID:18226460

  7. High resolution absorption cross sections in the transmission window region of the Schumann-Runge bands and Herzberg continuum of O2

    NASA Technical Reports Server (NTRS)

    Yoshino, K.; Esmond, J. R.; Cheung, A. S.-C.; Freeman, D. E.; Parkinson, W. H.

    1992-01-01

    Results are presented on measurements, conducted in the wavelength region 180-195 nm, and at different pressures of oxygen (between 2.5-760 torr) in order to separate the pressure-dependent absorption from the main cross sections, of the absorption cross sections of the Schumann-Runge bands in the window region between the rotational lines of S-R bands of O2. The present cross sections supersede the earlier published cross sections (Yoshino et al., 1983). The combined cross sections are presented graphically; they are available at wavenumber intervals of about 0.1/cm from the National Space Science Data Center. The Herzberg continuum cross sections are derived after subtracting calculated contributions from the Schumann-Runge bands. These are significantly smaller than any previous measurements.

  8. Evaluation of different indirect measures of rate of drug absorption in comparative pharmacokinetic studies.

    PubMed

    Lacey, L F; Keene, O N; Duquesnoy, C; Bye, A

    1994-02-01

    As indirect measures of rate of drug absorption (metrics), maximum plasma concentration (Cmax) is confounded by extent of drug absorption and the time to reach Cmax (tmax) is a discrete variable, dependent on blood sampling frequency. Building on the work of Endrenyi et al., we have compared different metrics, including Cmax/area under the curve of concentration versus time from time zero to infinity (AUC infinity), partial AUC from zero to tmax (AUCp), and Cmax.tmax with simulated experiments. Importantly, the performance of these metrics was assessed with the results of actual pharmacokinetic studies involving Glaxo drugs. The results of the simulated and real experiments were consistent and produced the following unambiguous findings: (1) Cmax/AUC infinity is a more powerful metric than Cmax in establishing bioequivalence when the formulations are truly bioequivalent; (2) Cmax/AUC infinity is more sensitive than Cmax at detecting differences in rate of absorption when they exist; and (3) the treatment ratios for AUCp, AUCp/AUC infinity, and Cmax.tmax are very imprecisely estimated and are of no practical value as measures of rate of absorption. Of the metrics examined, Cmax/AUC infinity is the most sensitive and powerful indirect measure of rate of drug absorption in comparative pharmacokinetic studies involving immediate-release dosage forms and should be used instead of Cmax in bioequivalence testing. PMID:8169791

  9. Ophthalmic drug delivery utilizing two-photon absorption: a novel approach to treat posterior capsule opacification

    NASA Astrophysics Data System (ADS)

    Kim, H.-C.; Träger, J.; Zorn, M.; Haberkorn, N.; Hampp, N.

    2007-07-01

    Intraocular lens (IOL) implantation is the standard technique to treat cataract. Despite recent progress in surgical procedures, posterior capsule opacification is one of the sill remaining postoperative complications of cataract surgery. We present a novel strategy to reduce the incidence of posterior capsule opacification. A drug delivery polymer suitable for manufacturing intraocular lenses has been developed which enables repeated drug release in a non-invasive and controlled manner. The therapeutic molecules are attached through a UV light sensitive linkage to the polymer backbone which is mainly responsible for the optical properties of the intraocular lenses. However, UV light can not trigger the release of drug from the polymer due to the high absorption of the cornea. We developed linkers which enable drug release by two-photon absorption induced cleavage of the linker structure. Since the two-photon absorption requires high photon densities, this does not occur in ambient light conditions in daily life, but is easily triggered by focused laser beams from a pulsed laser. In this proof-of-principle study we have employed a cyclobutane type linker and investigated the properties of the therapeutic system with the approved drugs 5-fluorouracil and chlorambucil. The controlled drug delivery was successfully demonstrated in vitro and additional cell tests confirmed that the device itself shows no cytotoxicity until photochemical activation. This presented concept can provide a powerful method in ophthalmic drug delivery.

  10. Vascular perfused segments of human intestine as a tool for drug absorption.

    PubMed

    Wei, Yansheng; Neves, Liomar A A; Franklin, Tammy; Klyuchnikova, Nadya; Placzek, Benjamin; Hughes, Helen M; Curtis, C Gerald

    2009-04-01

    Blood-based vascular perfusion of isolated segments of human jejunum was developed as a tool for drug absorption studies before clinical trials. Acceptance criteria for viable human gut preparations included stable blood flow, arterial pressure, glucose utilization, active peristalsis, oxygen uptake, less than 3% absorption of a 70,000 mol. wt. dextran, and a ratio of first-order absorption rate constants (k(a)) of antipyrine to terbutaline of > or =1.4. Mannitol absorption was less than that of antipyrine but larger than that of terbutaline and could not be used as a negative control in absorption studies with human intestine. In separate perfusions (n = 3) a cassette of nine drugs was administered into the gut lumen, and the net absorption of each drug into the circulation was measured over 75 min. Using the mean values of k(a), the test compounds could be ranked into four groups: group 1: sulfasalazine and furosemide, k(a) = 3.9 to 4.0 x 10(-3) min(-1); group 2: cimetidine, timolol, nadolol, and ranitidine, k(a) = 6.4 to 8.3 x 10(-3) min(-1); group 3: atenolol and metoprolol, k(a) = 9.6 x 10(-3) min(-1); and group 4: theophylline, k(a) = 17.5 x 10(-3) min(-1). The rationale for evaluating yet another oral absorption system was as follows: first, a human gut segment with an intact vascular system is the closest system available to a clinical trial without performing one; and second, the data generated would be a direct measure of net drug transport from the gut lumen into the vascular circulation under near physiological conditions, which is not possible in models lacking a blood supply. PMID:19118133

  11. Quantitative determination of percutaneous absorption of radiolabeled drugs in vitro and in vivo by human skin.

    PubMed

    Schaefer, H; Stüttgen, G; Zesch, A; Schalla, W; Gazith, J

    1978-01-01

    We have measured concentrations of about 30 drugs in the living layers of the skin under conditions which provide data which are applicable in therapeutic treatment. Since the skin is a thin organ and small amounts of drug represent high target concentrations, it is necessary to select a sensitive quantitative method; observation of the kinetics of absorption using radiolabeled drugs is the method of choice. Because of possible hazards--and legal and ethical problems--absorption studies in human skin are commonly performed in vitro. Related in vivo investigations demonstrate the relevance and the limitations of the in vitro experiments. The main hindrance against penetration of drugs is by the horny layer. The barrier-function of this layer--if it is undisturbed--may be described by a multilayer model. The reciprocal function, the reservoir function, is important for the efficiency of topical treatment; it also plays a role in determining the unique pharmacokinetics of drug absorption in the skin and percutaneous resorption. If the horny layer is injured, i.e. in diseased skin, both the barrier and the reservoir functions are disturbed. In consequence, drug concentrations in the skin--and percutaneous resorption--may be greatly enhanced, and topically applied drugs may enter preferentially into diseased areas. The form of application, such as ointment, solution, etc. influences the penetration kinetics in such a specific manner that a specific vehicle for a specific drug should always be postulated. The frequently discussed hazards of side effects due to percutaneous resorption of drugs like corticosteroids are a function of the treated area rather than of its penetration capacity. Thus the indication for local or oral treatment of severe dermatoses should be considered in terms of the affected area. The relatively frequent side effects in the skin itself which originate from unnecessarily high drug concentrations and long term treatment must also be taken into

  12. Rate- and Extent-Limiting Factors of Oral Drug Absorption: Theory and Applications.

    PubMed

    Sugano, Kiyohiko; Terada, Katsuhide

    2015-09-01

    The oral absorption of drugs has been represented by various concepts such as the absorption potential, the maximum absorbable dose, the biopharmaceutics classification system, and in vitro-in vivo correlation. The aim of this article is to provide an overview of the theoretical relationships between these concepts. It shows how a simple analytical solution for the fraction of a dose absorbed (Fa equation) can offer a theoretical base to tie together the various concepts, and discusses how this solution relates to the rate-limiting cases of oral drug absorption. The article introduces the Fa classification system as a framework in which all the above concepts were included, and discusses its applications for food effect prediction, active pharmaceutical ingredient form selection, formulation design, and biowaiver strategy. PMID:25712830

  13. [Pharmacokinetic comparison of baicalin absorption medicine Qinbai Qingfei concentrated pellets drug compatibility].

    PubMed

    Li, Hai-Long; Feng, Wen-Cheng; Yao, Lin; Sun, Yan; Song, Ya-Juan; Hu, Hao; Wang, Wei-Ming

    2014-05-01

    The Qinbai Qingfei concentrated pellets by traditional Chinese medicine theoryand party and group, the rats were given the drugs group, comparison of pharmacokinetics parameters changes of baicalin , discusses the rationality of Qinbai prescription. The rats were gavaged monarch drug group (Huang Qincu extract, mainly forbaicalin), and official medicine group, adjuvant group, medicine group and Qinbai group (Quan Fangzu) the content of baicalin equal as the monarch drug group, in the 28 h collection in rat plasma at different time point, application of HPLC determination of baicalin glycosides in rat plasmaconcentration time curve, with 3P97 practical pharmacokinetics program to process the data Based on the data analysis, baicalin in rat plasma of Qinbai group Cmax is 4 times as big as monarch druggroup, AUC is 6 times as big as monarch drug group; the content of baicalin in plasma of rats the highest is Qinbai group, the minister drug group, adjuvant group, medicine group of baicalin in rat plasma content of less than the Qinbai group, but was significantly higher than that of monarch drug group; the medicine group is slightly higher than that adjuvant the content of baicalin in plasma of rats. The pharmacokinetic results show that the measured plasma concentration in rats that Qinbai can significantly increase Cmax and AUC of baicalin, other components of qinbai can promoted the baicalin absorption in vivo. It showed that the reasonable of Qinbai compound compatibility. The minister drug can promote the absorption of baicalin in vivo. PMID:25282909

  14. Mechanisms of membrane transport of poorly soluble drugs: role of micelles in oral absorption processes.

    PubMed

    Yano, Koji; Masaoka, Yoshie; Kataoka, Makoto; Sakuma, Shinji; Yamashita, Shinji

    2010-03-01

    Micelles formed in the GI tract by bile acid and lecithin play an important role in oral absorption of poorly soluble drugs. In this situation, the drug molecules are present in equilibrium between the free and micellar states. In this study, the relationship between the free drug concentration and the membrane permeability of poorly soluble drugs was examined. Permeability across a Caco-2 monolayer and a dialysis membrane were measured in a side-by-side chamber system. The concentrations of sodium taurocholate (NaTC) and lecithin were varied to allow measurement of membrane permeability at different concentrations of free drugs. For troglitazone, hexylparaben, and heptylparaben, an increase in the NaTC and lecithin concentrations caused the permeability across the Caco-2 monolayer to decrease slightly, whereas the permeability across the dialysis membrane decreased markedly. In contrast, the changes in permeability of griseofulvin with an increased micelle concentration were similar for the Caco-2 monolayer and the dialysis membrane. Assuming that the permeability for the dialysis membrane reflects the free drug concentration in the medium, these results suggest that troglitazone and alkylparabens, but not griseofulvin, can partition directly from micelles to Caco-2 monolayers. This mechanism may contribute to oral absorption of drugs that are poorly soluble in water. PMID:19743502

  15. Accurate measurements and temperature dependence of the water vapor self-continuum absorption in the 2.1 μm atmospheric window

    SciTech Connect

    Ventrillard, I.; Romanini, D.; Mondelain, D.; Campargue, A.

    2015-10-07

    In spite of its importance for the evaluation of the Earth radiative budget, thus for climate change, very few measurements of the water vapor continuum are available in the near infrared atmospheric windows especially at temperature conditions relevant for our atmosphere. In addition, as a result of the difficulty to measure weak broadband absorption signals, the few available measurements show large disagreements. We report here accurate measurements of the water vapor self-continuum absorption in the 2.1 μm window by Optical Feedback Cavity Enhanced Absorption Spectroscopy (OF-CEAS) for two spectral points located at the low energy edge and at the center of the 2.1 μm transparency window, at 4302 and 4723 cm{sup −1}, respectively. Self-continuum cross sections, C{sub S}, were retrieved with a few % relative uncertainty, from the quadratic dependence of the spectrum base line level measured as a function of water vapor pressure, between 0 and 16 Torr. At 296 K, the C{sub S} value at 4302 cm{sup −1} is found 40% higher than predicted by the MT-CKD V2.5 model, while at 4723 cm{sup −1}, our value is 5 times larger than the MT-CKD value. On the other hand, these OF-CEAS C{sub S} values are significantly smaller than recent measurements by Fourier transform spectroscopy at room temperature. The temperature dependence of the self-continuum cross sections was also investigated for temperatures between 296 K and 323 K (23-50 °C). The derived temperature variation is found to be similar to that derived from previous Fourier transform spectrometer (FTS) measurements performed at higher temperatures, between 350 K and 472 K. The whole set of measurements spanning the 296-472 K temperature range follows a simple exponential law in 1/T with a slope close to the dissociation energy of the water dimer, D{sub 0} ≈ 1100 cm{sup −1}.

  16. Automation of cell-based drug absorption assays in 96-well format using permeable support systems.

    PubMed

    Larson, Brad; Banks, Peter; Sherman, Hilary; Rothenberg, Mark

    2012-06-01

    Cell-based drug absorption assays, such as Caco-2 and MDCK-MDR1, are an essential component of lead compound ADME/Tox testing. The permeability and transport data they provide can determine whether a compound continues in the drug discovery process. Current methods typically incorporate 24-well microplates and are performed manually. Yet the need to generate absorption data earlier in the drug discovery process, on an increasing number of compounds, is driving the use of higher density plates. A simple, more efficient process that incorporates 96-well permeable supports and proper instrumentation in an automated process provides more reproducible data compared to manual methods. Here we demonstrate the ability to perform drug permeability and transport assays using Caco-2 or MDCKII-MDR1 cells. The assay procedure was automated in a 96-well format, including cell seeding, media and buffer exchanges, compound dispense, and sample removal using simple robotic instrumentation. Cell monolayer integrity was confirmed via transepithelial electrical resistance and Lucifer yellow measurements. Proper cell function was validated by analyzing apical-to-basolateral and basolateral-to-apical movement of rhodamine 123, a known P-glycoprotein substrate. Apparent permeability and efflux data demonstrate how the automated procedure provides a less variable method than manual processing, and delivers a more accurate assessment of a compound's absorption characteristics. PMID:22357561

  17. In vitro percutaneous absorption enhancement of a lipophilic drug tamoxifen by terpenes.

    PubMed

    Gao, S; Singh, J

    1998-02-12

    Tamoxifen is a highly lipophilic drug that is widely used in breast malignancies and also as a prophylactic therapy in women at high risk for the development of this disease. Recently, the terpenes have been reported to show an enhancement effect on percutaneous drug absorption. The effect of terpenes (e.g. carvone, 1,8-cineole, menthol, and thymol) was studied on the in vitro percutaneous absorption of tamoxifen through porcine epidermis. The above terpenes (5% w/v) in combination with 50% ethanol significantly (P < 0.01) increased the permeability coefficient of tamoxifen in comparison to the control (50% ethanol). The solubility of tamoxifen was determined in the control and enhancer solutions to correct the permeability enhancement by way of fractional solubility adjustment. Binding of tamoxifen to powdered stratum corneum from control and enhancer solutions was also determined. Binding studies reveal that the enhancement in the permeability coefficient of tamoxifen by menthol and thymol is due at least in part, to improvement in the partitioning of the drug to the stratum corneum. In conclusion, terpenes in combination with ethanol can be used to enhance the percutaneous absorption of the highly lipophilic drug tamoxifen. PMID:9685917

  18. Drug marker absorption in relation to pellet size, gastric motility and viscous meals in humans

    NASA Technical Reports Server (NTRS)

    Rhie, J. K.; Hayashi, Y.; Welage, L. S.; Frens, J.; Wald, R. J.; Barnett, J. L.; Amidon, G. E.; Putcha, L.; Amidon, G. L.

    1998-01-01

    PURPOSE: The objective of this study was to evaluate drug marker absorption in relation to the gastric emptying (GE) of 0.7 mm and 3.6 mm enteric coated pellets as a function of viscosity and the underlying gastric motility. METHODS: Twelve subjects were evaluated in a 3-way crossover study. 0.7 mm caffeine and 3.6 mm acetaminophen enteric coated pellets were concurrently administered with a viscous caloric meal at the levels of 4000, 6000 and 8000 cP. Gastric motility was simultaneously measured with antral manometry and compared to time events in the plasma profiles of the drug markers. RESULTS: Caffeine, from the 0.7 mm pellets, was observed significantly earlier in the plasma than acetaminophen, from the 3.6 mm pellets, at all levels of viscosity. Motility related size differentiated GE was consistently observed at all viscosity levels, however, less variability was observed with the 4000 cP meal. Specifically, the onset of absorption from the of 3.6 mm pellets correlated with the onset of Phase II fasted state contractions (r = 0.929, p < 0.01). CONCLUSIONS: The timeframe of drug marker absorption and the onset of motility events were not altered within the range of viscosities evaluated. Rather, the differences in drug marker profiles from the non-digestible solids were most likely the result of the interaction between viscosity and motility influencing antral flow dynamics. The administration of the two sizes of pellets and a viscous caloric meal with subsequent monitoring of drug marker profiles is useful as a reference to assess the influence of motility patterns on the absorption profile of orally administered agents.

  19. Probabilistic modeling of percutaneous absorption for risk-based exposure assessments and transdermal drug delivery.

    SciTech Connect

    Ho, Clifford Kuofei

    2004-06-01

    Chemical transport through human skin can play a significant role in human exposure to toxic chemicals in the workplace, as well as to chemical/biological warfare agents in the battlefield. The viability of transdermal drug delivery also relies on chemical transport processes through the skin. Models of percutaneous absorption are needed for risk-based exposure assessments and drug-delivery analyses, but previous mechanistic models have been largely deterministic. A probabilistic, transient, three-phase model of percutaneous absorption of chemicals has been developed to assess the relative importance of uncertain parameters and processes that may be important to risk-based assessments. Penetration routes through the skin that were modeled include the following: (1) intercellular diffusion through the multiphase stratum corneum; (2) aqueous-phase diffusion through sweat ducts; and (3) oil-phase diffusion through hair follicles. Uncertainty distributions were developed for the model parameters, and a Monte Carlo analysis was performed to simulate probability distributions of mass fluxes through each of the routes. Sensitivity analyses using stepwise linear regression were also performed to identify model parameters that were most important to the simulated mass fluxes at different times. This probabilistic analysis of percutaneous absorption (PAPA) method has been developed to improve risk-based exposure assessments and transdermal drug-delivery analyses, where parameters and processes can be highly uncertain.

  20. Two-photon absorption-induced drug delivery from polymers for medical applications

    NASA Astrophysics Data System (ADS)

    Kim, Hee-Cheol; Kreiling, Stefan; Haertner, Sebastian; Hesse, Lutz; Greiner, Andreas; Hampp, Norbert A.

    2004-06-01

    Novel polymeric materials carrying a drug depot have been developed which are suitable for fabrication of photochemically modulated drug delivery devices. In order to avoid uncontrolled drug release the drug is covalently attached to the polymer backbone using a photo-active linker. Controlled drug release from the polymer can be accomplished either via single-photon excitation or by two-photon absorption (TPA). In particular the second possibility is of interest for applications where exposure to day light or UV light may not be omitted. One example are polymeric intraocular lenses (IOL), which are implanted instead of the opaque natural lens during cataract surgery. Secondary cataract formation is quite often observed after implantation of polymeric IOLs. In this study the well known cell toxic agent 5-fluorouracil (5FU) attached to a methylmethacrylate-based polymer was investigated as an IOL which can upon photochemical excitation release 5FU in order to treat or to prevent secondary cataract formation. The photochemical cleavage of the linker molecule was analyzed with single- and two-photon excitation. UV/VIS spectroscopy and HPLC analysis confirmed the release of 5FU form the polymer backbone. The diffusion of the drug precursor out from the polymer as well as the hydrolysis of the drug precursor which leads to 5FU formation were investigated in vitro.

  1. Two-photon absorption induced drug delivery from polymeric intraocular lenses

    NASA Astrophysics Data System (ADS)

    Hampp, Norbert A.; Kim, Hee-Cheol; Kreiling, Stefan; Hesse, Lutz; Greiner, Andreas

    2003-10-01

    Secondary cataracts are quite often observed after implantation of polymeric intraocular lenses. The reason for this complication is that lens epithelial cells remain in the capsular bag when the natural lens is removed. They begin proliferation and cause secondary cataracts. It is not desireable to add cell toxic agents at the time of the implantation because wound healing is negatively affected. We have developed polymeric intraocular lenses which are equipped with a drug depot which may be released non-invasively through photochemical treatment. In the example presented the drug is 5-fluoruracil (5FU) which is covalently bound to the polymer. Deliberation of 5FU from the polymer is done photochemically. Since light is transmitted permanently through the artificial intraocular lens and wearing of special glasses by the patient should be omitted conventional photochemistry is not a suitable tool for the drug release. The polymer-5FU linkage is designed in a way that it has a high two-photon absorption cross-section. Two-photon absorption is used to selectively release 5FU from the lens. The one-photon reaction is blocked since the cornea does absorb UV light. The principle shown here is not limited to 5FU but may be applied to other drugs also.

  2. Improved intestinal absorption of a poorly water-soluble oral drug using mannitol microparticles containing a nanosolid drug dispersion.

    PubMed

    Nishino, Yukiko; Kubota, Aya; Kanazawa, Takanori; Takashima, Yuuki; Ozeki, Tetsuya; Okada, Hiroaki

    2012-11-01

    A nozzle for a spray dryer that can prepare microparticles of water-soluble carriers containing various nanoparticles in a single step was previously developed in our laboratory. To enhance the solubility and intestinal absorption of poorly water-soluble drugs, we used probucol (PBL) as a poorly water-soluble drug, mannitol (MAN) as a water-soluble carrier for the microparticles, and EUDRAGIT (EUD) as a polymer vehicle for the solid dispersion. PBL-EUD-acetone-methanol and aqueous MAN solutions were simultaneously supplied through different liquid passages of the spray nozzle and dried together. PBL-EUD solid dispersion was nanoprecipitated in the MAN solution using an antisolvent mechanism and rapidly dried by surrounding it with MAN. PBL in the dispersion vehicle was amorphous and had higher physical stability according to powder X-ray diffraction and differential scanning calorimetry analysis. The bioavailability of PBL in PBL-EUD S-100-MAN microparticles after oral administration in rats was markedly higher (14- and 6.2-fold, respectively) than that of the original PBL powder and PBL-MAN microparticles. These results demonstrate that the composite microparticles containing a nanosized solid dispersion of a poorly water-soluble drug prepared using the spray nozzle developed by us should be useful to increase the solubility and bioavailability of drugs after oral administration. PMID:22864998

  3. Influence of Food on Paediatric Gastrointestinal Drug Absorption Following Oral Administration: A Review

    PubMed Central

    Batchelor, Hannah K.

    2015-01-01

    The objective of this paper was to review existing information regarding food effects on drug absorption within paediatric populations. Mechanisms that underpin food–drug interactions were examined to consider potential differences between adult and paediatric populations, to provide insights into how this may alter the pharmacokinetic profile in a child. Relevant literature was searched to retrieve information on food–drug interaction studies undertaken on: (i) paediatric oral drug formulations; and (ii) within paediatric populations. The applicability of existing methodology to predict food effects in adult populations was evaluated with respect to paediatric populations where clinical data was available. Several differences in physiology, anatomy and the composition of food consumed within a paediatric population are likely to lead to food–drug interactions that cannot be predicted based on adult studies. Existing methods to predict food effects cannot be directly extrapolated to allow predictions within paediatric populations. Development of systematic methods and guidelines is needed to address the general lack of information on examining food–drug interactions within paediatric populations. PMID:27417362

  4. High-performance dispersive Raman and absorption spectroscopy as tools for drug identification

    NASA Astrophysics Data System (ADS)

    Pawluczyk, Olga; Andrey, Sam; Nogas, Paul; Roy, Andrew; Pawluczyk, Romuald

    2009-02-01

    Due to increasing availability of pharmaceuticals from many sources, a need is growing to quickly and efficiently analyze substances in terms of the consistency and accuracy of their chemical composition. Differences in chemical composition occur at very low concentrations, so that highly sensitive analytical methods become crucial. Recent progress in dispersive spectroscopy with the use of 2-dimensional detector arrays, permits for signal integration along a long (up to 12 mm long) entrance slit of a spectrometer, thereby increasing signal to noise ratio and improving the ability to detect small concentration changes. This is achieved with a non-scanning, non-destructive system. Two different methods using P&P Optica high performance spectrometers were used. High performance optical dispersion Raman and high performance optical absorption spectroscopy were employed to differentiate various acetaminophen-containing drugs, such as Tylenol and other generic brands, which differ in their ingredients. A 785 nm excitation wavelength was used in Raman measurements and strong Raman signals were observed in the spectral range 300-1800 cm-1. Measurements with the absorption spectrometer were performed in the wavelength range 620-1020 nm. Both Raman and absorption techniques used transmission light spectrometers with volume phase holographic gratings and provided sufficient spectral differences, often structural, allowing for drug differentiation.

  5. Enhanced dissolution and oral absorption of tacrolimus by supersaturable self-emulsifying drug delivery system.

    PubMed

    Lee, Dae Ro; Ho, Myoung Jin; Jung, Hyuck Jun; Cho, Ha Ra; Park, Jun Seo; Yoon, Suk-Hyun; Choi, Yong Seok; Choi, Young Wook; Oh, Chung-Hun; Kang, Myung Joo

    2016-01-01

    A new Soluplus (polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer)-based supersaturable self-emulsifying drug delivery system (S-SEDDS) was formulated to enhance oral absorption of tacrolimus (FK506) with minimal use of oil, surfactant, and cosurfactant. A high payload supersaturable system (S-SEDDS) was prepared by incorporating Soluplus, as a precipitation inhibitor, to SEDDS consisting of Capmul MCM, Cremophor EL, and Transcutol (FK506:vehicle:Soluplus =1:15:1). In vitro dissolution profile and in vitro pharmacokinetic aspect of S-SEDDS in rats were comparatively evaluated with those of conventional SEDDS formulas containing four times greater content of vehicle components (FK506:vehicle =1:60). Both formulations formed spherical drug-loaded microemulsion <70 nm in size when in contact with aqueous medium. In an in vitro dissolution test in a nonsink condition, the amphiphilic polymer noticeably retarded drug precipitation and maintained >80% of accumulated dissolution rate for 24 hours, analogous to that from conventional SEDDS. Moreover, pharmacokinetic parameters of the maximum blood concentration and area under the curve from S-SEDDS formula in rats were not statistically different (P>0.05) than those of conventional SEDDS. The results suggest that the Soluplus-based supersaturable system can be an alternative to achieve a comparable in vitro dissolution profile and in vivo oral absorption with conventional SEDDS, with minimal use of vehicle ingredients. PMID:27051286

  6. Enhanced dissolution and oral absorption of tacrolimus by supersaturable self-emulsifying drug delivery system

    PubMed Central

    Lee, Dae Ro; Ho, Myoung Jin; Jung, Hyuck Jun; Cho, Ha Ra; Park, Jun Seo; Yoon, Suk-Hyun; Choi, Yong Seok; Choi, Young Wook; Oh, Chung-Hun; Kang, Myung Joo

    2016-01-01

    A new Soluplus (polyvinyl caprolactam–polyvinyl acetate–polyethylene glycol graft copolymer)-based supersaturable self-emulsifying drug delivery system (S-SEDDS) was formulated to enhance oral absorption of tacrolimus (FK506) with minimal use of oil, surfactant, and cosurfactant. A high payload supersaturable system (S-SEDDS) was prepared by incorporating Soluplus, as a precipitation inhibitor, to SEDDS consisting of Capmul MCM, Cremophor EL, and Transcutol (FK506:vehicle:Soluplus =1:15:1). In vitro dissolution profile and in vitro pharmacokinetic aspect of S-SEDDS in rats were comparatively evaluated with those of conventional SEDDS formulas containing four times greater content of vehicle components (FK506:vehicle =1:60). Both formulations formed spherical drug-loaded microemulsion <70 nm in size when in contact with aqueous medium. In an in vitro dissolution test in a nonsink condition, the amphiphilic polymer noticeably retarded drug precipitation and maintained >80% of accumulated dissolution rate for 24 hours, analogous to that from conventional SEDDS. Moreover, pharmacokinetic parameters of the maximum blood concentration and area under the curve from S-SEDDS formula in rats were not statistically different (P>0.05) than those of conventional SEDDS. The results suggest that the Soluplus-based supersaturable system can be an alternative to achieve a comparable in vitro dissolution profile and in vivo oral absorption with conventional SEDDS, with minimal use of vehicle ingredients. PMID:27051286

  7. Amorphous Solid Dispersions or Prodrugs: Complementary Strategies to Increase Drug Absorption.

    PubMed

    Rumondor, Alfred C F; Dhareshwar, Sundeep S; Kesisoglou, Filippos

    2016-09-01

    Maximizing oral bioavailability of drug candidates represents a challenge in the pharmaceutical industry. In recent years, there has been an increase in the use of amorphous solid dispersions (ASDs) to address this issue, where a growing number of solid dispersion formulations have been introduced to the market. However, an increase in solubility or dissolution rate through ASD does not always result in sufficient improvement of oral absorption because solubility limitations may still exist at high doses. Chemical modification in the form of a prodrug may offer an alternative approach for these cases. Although prodrugs have been primarily used to improve membrane permeability, examples are available in which prodrugs have been used to increase drug solubility beyond what can be achieved via formulation approaches. In this mini review, the role of ASDs and prodrugs as 2 complementary approaches in improving oral bioavailability of drug candidates is discussed. We discuss the fundamental principles of absorption and bioavailability, and review available literature on both solid dispersions and prodrugs, providing a summary of their use and examples of successful applications, and cover some of the biopharmaceutics evaluation aspects for these approaches. PMID:26886316

  8. Influence of pH on Drug Absorption from the Gastrointestinal Tract: A Simple Chemical Model

    NASA Astrophysics Data System (ADS)

    Hickman, Raymond J. S.; Neill, Jane

    1997-07-01

    A simple model of the gastrointestinal tract is obtained by placing ethyl acetate in contact with water at pH 2 and pH 8 in separate test tubes. The ethyl acetate corresponds to the lipid material lining the tract while the water corresponds to the aqueous contents of the stomach (pH 2) and intestine (pH 8). The compounds aspirin, paracetamol and 3-aminophenol are used as exemplars of acidic, neutral and basic drugs respectively to illustrate the influence which pH has on the distribution of each class of drug between the aqueous and organic phases of the model. The relative concentration of drug in the ethyl acetate is judged by applying microlitre-sized samples of ethyl acetate to a layer of fluorescent silica which, after evaporation of the ethyl acetate, is viewed under an ultraviolet lamp. Each of the three drugs, if present in the ethyl acetate, becomes visible as a dark spot on the silica layer. The observations made in the model system correspond well to the patterns of drug absorption from the gastrointestinal tract described in pharmacology texts and these observations are convincingly explained in terms of simple acid-base chemistry.

  9. Human in vivo regional intestinal permeability: quantitation using site-specific drug absorption data.

    PubMed

    Sjögren, Erik; Dahlgren, David; Roos, Carl; Lennernäs, Hans

    2015-06-01

    Application of information on regional intestinal permeability has been identified as a key aspect of successful pharmaceutical product development. This study presents the results and evaluation of an approach for the indirect estimation of site-specific in vivo intestinal effective permeability (Peff) in humans. Plasma concentration-time profiles from 15 clinical studies that administered drug solutions to specific intestinal regions were collected and analyzed. The intestinal absorption rate for each drug was acquired by deconvolution, using historical intravenous data as reference, and used with the intestinal surface area and the dose remaining in the lumen to estimate the Peff. Forty-three new Peff values were estimated (15 from the proximal small intestine, 11 from the distal small intestine, and 17 from the large intestine) for 14 active pharmaceutical ingredients representing a wide range of biopharmaceutical properties. A good correlation (r(2) = 0.96, slope = 1.24, intercept = 0.030) was established between these indirect jejunal Peff estimates and jejunal Peff measurements determined directly using the single-pass perfusion double balloon technique. On average, Peff estimates from the distal small intestine and large intestine were 90% and 40%, respectively, of those from the proximal small intestine. These results support the use of the evaluated deconvolution method for indirectly estimating regional intestinal Peff in humans. This study presents the first comprehensive data set of estimated human regional intestinal permeability values for a range of drugs. These biopharmaceutical data can be used to improve the accuracy of gastrointestinal absorption predictions used in drug development decision-making. PMID:25919764

  10. The Effect of Digestion and Drug Load on Halofantrine Absorption from Self-nanoemulsifying Drug Delivery System (SNEDDS).

    PubMed

    Michaelsen, Maria Høtoft; Wasan, Kishor M; Sivak, Olena; Müllertz, Anette; Rades, Thomas

    2016-01-01

    A super-saturated self-nanoemulsifying drug delivery system (super-SNEDDS), containing the poorly water-soluble drug halofantrine (Hf) at 150% of equilibrium solubility (S eq), was compared in vitro and in vivo with a conventional SNEDDS (75% of S eq) with respect to bioavailability and digestibility. Further, the effect of digestion on oral absorption of Hf from SNEDDS and super-SNEDDS was assessed by incorporation of the lipase inhibitor tetrahydrolipstatin (orlistat) into the SNEDDS. The SNEDDS contained soybean oil/Maisine 34-I (1:1), Kolliphor RH40, and ethanol at a ratio of 55:35:10, w/w percent. For the dynamic in vitro lipolysis, the precipitation of Hf at 60 min was significantly larger for the super-SNEDDS (66.8 ± 16.4%) than for the SNEDDS (18.5 ± 9.2%). The inhibition of the in vitro digestion by orlistat (1% (w/w)) lowered drug precipitation significantly for both the super-SNEDDS (36.8 ± 1.7%) and the SNEDDS (3.9 ± 0.7%). In the in vivo studies, the super-SNEDDS concept proved valid in a rat model with a significantly larger C max for the super-SNEDDS (964 ± 167 ng/mL) than for the SNEDDS (506 ± 112 ng/mL). The bioavailability of Hf dosed in super-SNEDDS (32.9 ± 3.6%) and SNEDDS (22.5 ± 6.3%) did not change significantly with co-administration of orlistat (45.5 ± 7.3% and 21.9 ± 6.5%, respectively). However, the pharmacokinetic parameters changed; the t max of the super-SNEDDS (1.3 ± 0.1 h) and SNEDDS (2.8 ± 1.2 h) were significantly lower when dosed with orlistat (6.0 ± 1.3 and 6.3 ± 1.2 h, respectively). These findings suggest that the role of lipid digestion for the absorption of drugs from SNEDDS may be less important than previously thought. PMID:26486790

  11. The effects of microRNA on the absorption, distribution, metabolism and excretion of drugs

    PubMed Central

    He, Y; Chevillet, J R; Liu, G; Kim, T K; Wang, K

    2015-01-01

    The importance of genetic factors (e.g. sequence variation) in the absorption, distribution, metabolism, excretion (ADME) and overall efficacy of therapeutic agents is well established. Our ability to identify, interpret and utilize these factors is the subject of much clinical investigation and therapeutic development. However, drug ADME and efficacy are also heavily influenced by epigenetic factors such as DNA/histone methylation and non-coding RNAs [especially microRNAs (miRNAs)]. Results from studies using tools, such as in silico miRNA target prediction, in vitro functional assays, nucleic acid profiling/sequencing and high-throughput proteomics, are rapidly expanding our knowledge of these factors and their effects on drug metabolism. Although these studies reveal a complex regulation of drug ADME, an increased understanding of the molecular interplay between the genome, epigenome and transcriptome has the potential to provide practically useful strategies to facilitate drug development, optimize therapeutic efficacy, circumvent adverse effects, yield novel diagnostics and ultimately become an integral component of personalized medicine. PMID:25296724

  12. A sequential algorithm for the non-linear dual-sorption model of percutaneous drug absorption.

    PubMed

    Gumel, A B; Kubota, K; Twizell, E H

    1998-08-15

    A sequential algorithm is developed for the non-linear dual-sorption model developed by Chandrasekaran et al. [1,2] which monitors pharmacokinetic profiles in percutaneous drug absorption. In the experimental study of percutaneous absorption, it is often observed that the lag-time decreases with the increase in the donor concentration when two or more donor concentrations of the same compound are used. The dual-sorption model has sometimes been employed to explain such experimental results. In this paper, it is shown that another feature observed after vehicle removal may also characterize the dual-sorption model. Soon after vehicle removal, the plots of the drug flux versus time become straight lines on a semilogarithmic scale as in the linear model, but the half-life is prolonged thereafter when the dual-sorption model prevails. The initial half-life after vehicle removal with a low donor concentration is longer than that with a higher donor concentration. These features, if observed in experiments, may be used as evidence to confirm that the dual-sorption model gives an explanation to the non-linear kinetic behaviour of a permeant. PMID:9727298

  13. In vitro testing of drug absorption for drug 'developability' assessment: forming an interface between in vitro preclinical data and clinical outcome.

    PubMed

    Sun, Duxin; Yu, Lawrence X; Hussain, Munir A; Wall, Doris A; Smith, Ronald L; Amidon, Gordon L

    2004-01-01

    Drug 'developability' assessment has become an increasingly important addition to traditional drug efficacy and toxicity evaluations, as pharmaceutical scientists strive to accelerate drug discovery and development processes in a time- and cost-effective manner. The fraction of drug absorbed and the maximum absorbable dose (MAD) can be estimated from in vivo clinical pharmacokinetics, mass balance studies or in vivo drug permeability in humans by different calculation methods. Unfortunately, in vivo data are usually unavailable at the early stages of drug discovery and development, and in vitro screening for the permeability, solubility, activity and toxicity of a drug has become a routine measurement in drug discovery and development. These in vitro data could be used to predict drug 'developability' with different calculation methods before selecting candidates for clinical evaluation. The fraction of drug absorbed in human could be predicted by in vivo human permeability or in vitro Caco2 permeability. For example, if drug permeability in Caco2 cells reaches 13.3 to 18.1 x 10(-6) cm/s, its predicted in vivo permeability in humans would reach 2 x 10(-4) cm/s, and its predicted fraction of drug absorbed would be > 90%, which is defined as highly permeable. The MAD could also be predicted with in vitro permeability, or calculated absorption rate constant. In addition, in vitro solubility and permeability data can also be used for the biopharmaceutics classification system (BCS) and, subsequently, to direct formulation optimization strategies. If drug 'developability' becomes an obstacle for drug delivery based on these in vitro data and predictions at the early stages of drug discovery and development, options such as prodrug approaches could be explored to enhance drug 'developability', in addition to different formulation methods. Therefore, in vitro absorption testing is a highly valuable tool in the decision-making process to select candidates for in vivo

  14. Distinguishing between the Permeability Relationships with Absorption and Metabolism To Improve BCS and BDDCS Predictions in Early Drug Discovery

    PubMed Central

    2015-01-01

    The biopharmaceutics classification system (BCS) and biopharmaceutics drug distribution classification system (BDDCS) are complementary classification systems that can improve, simplify, and accelerate drug discovery, development, and regulatory processes. Drug permeability has been widely accepted as a screening tool for determining intestinal absorption via the BCS during the drug development and regulatory approval processes. Currently, predicting clinically significant drug interactions during drug development is a known challenge for industry and regulatory agencies. The BDDCS, a modification of BCS that utilizes drug metabolism instead of intestinal permeability, predicts drug disposition and potential drug–drug interactions in the intestine, the liver, and most recently the brain. Although correlations between BCS and BDDCS have been observed with drug permeability rates, discrepancies have been noted in drug classifications between the two systems utilizing different permeability models, which are accepted as surrogate models for demonstrating human intestinal permeability by the FDA. Here, we recommend the most applicable permeability models for improving the prediction of BCS and BDDCS classifications. We demonstrate that the passive transcellular permeability rate, characterized by means of permeability models that are deficient in transporter expression and paracellular junctions (e.g., PAMPA and Caco-2), will most accurately predict BDDCS metabolism. These systems will inaccurately predict BCS classifications for drugs that particularly are substrates of highly expressed intestinal transporters. Moreover, in this latter case, a system more representative of complete human intestinal permeability is needed to accurately predict BCS absorption. PMID:24628254

  15. Utility of physiologically based absorption modeling in implementing Quality by Design in drug development.

    PubMed

    Zhang, Xinyuan; Lionberger, Robert A; Davit, Barbara M; Yu, Lawrence X

    2011-03-01

    To implement Quality by Design (QbD) in drug development, scientists need tools that link drug products properties to in vivo performance. Physiologically based absorption models are potentially useful tools; yet, their utility of QbD implementation has not been discussed or explored much in the literature. We simulated pharmacokinetics (PK) of carbamazepine (CBZ) after administration of four oral formulations, immediate-release (IR) suspension, IR tablet, extended-release (XR) tablet and capsule, under fasted and fed conditions and presented a general diagram of a modeling and simulation strategy integrated with pharmaceutical development. We obtained PK parameters and absorption scale factors (ASFs) by deconvolution of the PK data for IR suspension under fasted condition. The model was validated for other PK profiles of IR formulations and used to predict PK for XR formulations. We explored three key areas where a modeling and simulation approach impacts QbD. First, the model was used to help identify optimal in vitro dissolution conditions for XR formulations. Second, identification of critical formulations variables was illustrated by a parameter sensitivity analysis of mean particle radius for the IR tablet that showed a PK shift with decreased particle radius, C (max) was increased and T (max) was decreased. Finally, virtual trial simulations allowed incorporation of inter-subject variability in the model. Virtual bioequivalence studies performed for two test formulations suggested that an in vitro dissolution test may be a more sensitive discriminative method than in vivo PK studies. In summary, a well-validated predictive model is a potentially useful tool for QbD implementation in drug development. PMID:21207216

  16. Relationships between human intestinal absorption and polar interactions drug/phospholipids estimated by IAM-HPLC.

    PubMed

    Grumetto, Lucia; Russo, Giacomo; Barbato, Francesco

    2015-07-15

    Phospholipid affinity indexes (logkW(IAM)) for 15 structurally non-related basic, acidic, ampholytic, and neutral drugs were measured by HPLC on two different phospholipid stationary phases (immobilized artificial membrane - IAM). According to a method we previously proposed, polar and electrostatic forces involved in drug/membrane interactions were quantified both as ΔlogkW(IAM) and as Δ(')logkW(IAM). These values are the differences between the experimental logkW(IAM) and the values expected for a neutral compound having the lipophilicity value equal to either that of the neutral form of the analyte (logP(N)) or that of the mixture of charged and neutral forms of the analyte at jejunum pH 6.5 (logD(6.5)), respectively. Jejunum absorption values, logPeff, measured by the Loc-I-Gut technique, did not relate with logkW(IAM) values. A moderate linear relationship was observed with logP(N) values for all the analytes and a weak parabolic relationship was observed with logD(6.5) values, but only after the exclusion of two analytes. In contrast, a highly significant linear inverse relationship was observed with ΔlogkW(IAM) values. Therefore, differently from the results of our recent studies on blood-brain barrier passage, the intestinal absorption data for not only bases and zwitterions but also for acids relate significantly with ΔlogkW(IAM) and not with Δ(')logkW(IAM) values. The results suggest that membrane passage at jejunum level can be described according to the "flip-flop" model; indeed, the lipophilicity of the neutral forms (logP(N)) appears related to the passage through the non-polar inner moieties of phospholipids whereas ΔlogkW(IAM) parameter appears related to the "trapping" forces at their polar surfaces. The method, easy to perform and at medium throughput, could be of use for preliminary screening of new drugs based on oral absorption potential. PMID:25917756

  17. Development of a Triplet-Triplet Absorption Ruler: DNA- and Chromatin-Mediated Drug Molecule Release from a Nanosurface.

    PubMed

    Chakraborty, Sudeshna Das; Sau, Abhishek; Kuznetsov, Denis V; Banerjee, Amrita; Bardhan, Munmun; Bhattacharya, Maireyee; Dasgupta, Dipak; Basu, Samita; Senapati, Dulal

    2016-07-14

    Triplet-triplet (T-T) absorption spectroscopy has been used successfully as a molecular ruler to understand the actual release process of sanguinarine as a drug molecule from a gold nanoparticle surface in the presence of cell components, that is, DNA and chromatin. The obtained results have been verified by fluorescence and surface-enhanced Raman spectroscopy (SERS), and a plausible explanation has been put forward to describe the underestimation and overestimation of the percentage (%) of the release of drug molecules measured by fluorescence- and SERS-based techniques, respectively, over the highlighted T-T absorption spectroscopy. Because of the intrinsic nature of absorption, the reported T-T absorption spectroscopic assay overpowers fluorescence- and SERS-based assays, which are limited by the long-range interaction and nonlinear dependence of the concentration of analytes, respectively. PMID:27284775

  18. A novel cell compatible impingement system to study in vitro drug absorption from dry powder aerosol formulations.

    PubMed

    Bur, Michael; Rothen-Rutishauser, Barbara; Huwer, Hanno; Lehr, Claus-Michael

    2009-06-01

    A modified Astra type multistage liquid impinger (MSLI) with integrated bronchial cell monolayers was used to study deposition and subsequent drug absorption on in vitro models of the human airway epithelial barrier. Inverted cell culture of Calu-3 cells on the bottom side of cell culture filter inserts was integrated into a compendial MSLI. Upside down cultivation did not impair the barrier function, morphology and viability of Calu-3 cells. Size selective deposition with subsequent absorption was studied for three different commercially available dry powder formulations of salbutamol sulphate and budesonide. After deposition without size separation the absorption rates from the aerosol formulations differed but correlated with the size of the carrier lactose particles. However, after deposition in the MSLI, simulating relevant impaction and causing the separation of small drug crystals from the carrier lactose, the absorption rates of the three formulations were identical, confirming the bioequivalence of the three formulations. PMID:18771729

  19. Aortopulmonary window

    MedlinePlus

    Aortopulmonary window is a rare heart defect in which there is a hole connecting the major artery taking blood ... rest of the body. Babies with an aortopulmonary window have a hole in between the aorta and ...

  20. [Inhibitory effect of nasal mucus on the absorption of drugs through respiratory epithelium].

    PubMed

    Hayashi, H

    1990-01-01

    The absorption of Dibekacin (DKB) through rabbit's tracheal mucosa with and without nasal mucus were examined in vitro. The modified double chamber method was used for the purpose of this study. DKB solution (20 mg/ml) and Hanks' balanced salt solution were put into the donor compartment (DC) and the receiver compartment (RC), respectively. A plate with a hole and the tracheal mucosa were inserted between the compartments in the order of DC, dialytic membrane, the plate, the rabbit tracheal mucosa and RC. The hole of the plate was filled with nasal mucus or Hanks' solution. The latter was used as the control. The chamber was incubated in a humidified atmosphere of 5% CO2 in air for 3 hours at 37 degrees C. The absorption rate (AR) was obtained by dividing the concentration of DKB in RC by that in DC. The nasal mucus from patients with chronic sinusitis significantly decreased the AR of DKB compared with that in the control (P less than 0.05). The AR significantly decreased with increments in the thickness of nasal mucus by chronic sinusitis. This decreased AR was improved by the addition of N-Acetyl-L-cysteine (NAC) to DKB solution in DC. NAC can cleave disulfied bonds of mucus glycoprotein and this results in the decrease of viscoelasticity of nasal mucus. The results indicate that nasal mucus by chronic sinusitis intercept the absorption of drugs through respiratory epithelium in vitro. One of the mechanisms of the intercepter may be due to the high molecular-reticular structure of nasal mucus. PMID:2319385

  1. Skin aging modulates percutaneous drug absorption: the impact of ultraviolet irradiation and ovariectomy.

    PubMed

    Hung, Chi-Feng; Chen, Wei-Yu; Aljuffali, Ibrahim A; Lin, Yin-Ku; Shih, Hui-Chi; Fang, Jia-You

    2015-01-01

    Ultraviolet (UV) exposure and menopause are known as the inducers of damage to the skin structure. The combination of these two factors accelerates the skin aging process. In this study, we aimed to evaluate the influence of UV and ovariectomy (OVX) on the permeation of drugs through the skin. The role of tight junctions (TJs) and adherens junctions (AJs) in the cutaneous absorption of extremely lipophilic permeants and macromolecules was explored. The OVX nude mouse underwent bilateral ovary removal. Both UVA and UVB were employed to irradiate the skin. The physiological and biochemical changes of the skin structure were examined with focus on transepidermal water loss (TEWL), skin color, immunohistochemistry, and mRNA levels of proteins. UVB and OVX increased TEWL, resulting in stratum corneum (SC) integrity disruption and dehydration. A hyperproliferative epidermis was produced by UVB. UVA caused a pale skin color tone due to keratinocyte apoptosis in the epidermis. E-cadherin and β-catenin showed a significant loss by both UVA and UVB. OVX downregulated the expression of filaggrin and involucrin. A further reduction was observed when UV and OVX were combined. The in vitro cutaneous absorption demonstrated that UV increased the skin permeation of tretinoin by about twofold. However, skin accumulation and flux of estradiol were not modified by photoaging. OVX basically revealed a negligible effect on altering the permeation of small permeants. OVX increased tretinoin uptake by the appendages from 1.36 to 3.52 μg/cm(2). A synergistic effect on tretinoin follicular uptake enhancement was observed for combined UV and OVX. However, the intervention of OVX to photoaged skin resulted in less macromolecule (dextran, molecular weight = 4 kDa) accumulation in the skin reservoir because of retarded partitioning into dry skin. The in vivo percutaneous absorption of lipophilic dye examined by confocal microscopy had indicated that the SC was still important to

  2. Melatonin not only restores but also prevents the inhibition of the intestinal Ca(2+) absorption caused by glutathione depleting drugs.

    PubMed

    Areco, Vanessa; Rodriguez, Valeria; Marchionatti, Ana; Carpentieri, Agata; Tolosa de Talamoni, Nori

    2016-07-01

    We have previously demonstrated that melatonin (MEL) blocks the inhibition of the intestinal Ca(2+) absorption caused by menadione (MEN). The purpose of this study were to determine whether MEL not only restores but also prevents the intestinal Ca(2+) absorption inhibited either by MEN or BSO, two drugs that deplete glutathione (GSH) in different ways, and to analyze the mechanisms by which MEN and MEL alter the movement of Ca(2+) across the duodenum. To know this, chicks were divided into four groups: 1) controls, 2) MEN treated, 3) MEL treated, and 4) treated sequentially with MEN and MEL or with MEN and MEL at the same time. In a set of experiments, chicks treated with BSO or sequentially with BSO and MEL or with BSO and MEL at the same time were used. MEL not only restored but also prevented the inhibition of the chick intestinal Ca(2+) absorption produced by either MEN or BSO. MEN altered the protein expression of molecules involved in the transcellular as well as in the paracellular pathway of the intestinal Ca(2+) absorption. MEL restored partially both pathways through normalization of the O2(-) levels. The nitrergic system was not altered by any treatment. In conclusion, MEL prevents or restores the inhibition of the intestinal Ca(2+) absorption caused by different GSH depleting drugs. It might become one drug for the treatment of intestinal Ca(2+) absorption under oxidant conditions having the advantage of low or null side effects. PMID:26970583

  3. Development of a Unified Dissolution and Precipitation Model and Its Use for the Prediction of Oral Drug Absorption.

    PubMed

    Jakubiak, Paulina; Wagner, Björn; Grimm, Hans Peter; Petrig-Schaffland, Jeannine; Schuler, Franz; Alvarez-Sánchez, Rubén

    2016-02-01

    Drug absorption is a complex process involving dissolution and precipitation, along with other kinetic processes. The purpose of this work was to (1) establish an in vitro methodology to study dissolution and precipitation in early stages of drug development where low compound consumption and high throughput are necessary, (2) develop a mathematical model for a mechanistic explanation of generated in vitro dissolution and precipitation data, and (3) extrapolate in vitro data to in vivo situations using physiologically based models to predict oral drug absorption. Small-scale pH-shift studies were performed in biorelevant media to monitor the precipitation of a set of poorly soluble weak bases. After developing a dissolution-precipitation model from this data, it was integrated into a simplified, physiologically based absorption model to predict clinical pharmacokinetic profiles. The model helped explain the consequences of supersaturation behavior of compounds. The predicted human pharmacokinetic profiles closely aligned with the observed clinical data. In summary, we describe a novel approach combining experimental dissolution/precipitation methodology with a mechanistic model for the prediction of human drug absorption kinetics. The approach unifies the dissolution and precipitation theories and enables accurate predictions of in vivo oral absorption by means of physiologically based modeling. PMID:26674605

  4. The isolated perfused bovine udder as an in vitro model of percutaneous drug absorption. Skin viability and percutaneous absorption of dexamethasone, benzoyl peroxide, and etofenamate.

    PubMed

    Kietzmann, M; Löscher, W; Arens, D; Maass, P; Lubach, D

    1993-10-01

    Using udders from slaughtered cows as a new in vitro model of percutaneous drug absorption, the tissue viability and the percutaneous absorption of dexamethasone, benzoyl peroxide, and etofenamate were studied. The organ was perfused with gassed tyrode solution for up to 6 hr. As shown by measurement of glucose consumption, lactate production, lactate dehydrogenase activity, and pH in the perfusate, the tissue was viable over a 6-hr period. This was confirmed by a histological examination. Determination of the udder skin-fold thickness demonstrated that no edema developed within the perfusion period. A maximum skin penetration of dexamethasone was found after administration of dexamethasone dissolved in acetone with dimethyl sulfoxide, followed by ointment with salicylic acid, ointment without salicylic acid, and acetone solution. Experiments with benzoyl peroxide and etofenamate demonstrated that the perfused udder skin was capable of metabolizing drugs in vitro. In conclusion, the isolated perfused bovine udder is a new in vitro model, which maintains bovine udder skin with an isolated vasculature in a viable state. Using this in vitro model, we note it is possible to compare the dermal penetration, metabolism, and absorption of substances after topical administration of different drug formulations. PMID:8298184

  5. In vitro-in vivo correlation of the effect of supersaturation on the intestinal absorption of BCS Class 2 drugs.

    PubMed

    Higashino, Haruki; Hasegawa, Tsubasa; Yamamoto, Mari; Matsui, Rie; Masaoka, Yoshie; Kataoka, Makoto; Sakuma, Shinji; Yamashita, Shinji

    2014-03-01

    The aim of this study was to establish an in vitro method for evaluating the effect of supersaturation on oral absorption of poorly water-soluble drugs in vivo. Albendazole, dipyridamole, gefitinib, and ketoconazole were used as model drugs. Supersaturation of each drug was induced by diluting its stock solution by fasted state simulated intestinal fluid (FaSSIF) (solvent-shift method), then dissolution and precipitation profile of the drug was observed in vitro. The crystalline form of the precipitate was checked by differential scanning calorimetry (DSC). For comparison, control suspension was prepared by suspending a drug powder directly into FaSSIF (powder-suspending method). In vivo intestinal absorption of the drug was observed in rats by determined the plasma concentration after intraduodenal administration of drug suspensions. For all drugs, suspensions prepared by solvent-shift method showed significantly higher dissolved concentration in vitro than that prepared by powder-suspending method, clearly indicated the induction of supersaturation. DSC analysis revealed that crystalline form of the precipitate profoundly affects the extent and the duration of supersaturation. A rat in vivo study confirmed that the supersaturation of these drugs increased the fraction absorbed from the intestine, which corresponded well to the in vitro dissolution and precipitation profile of drugs except for ketoconazole. For ketoconazole, an in vivo absorption study was performed in rats pretreated with 1-aminobenzotriazole, a potent inhibitor of CYP mediated metabolism. CYP inhibition study suggested that the high luminal concentration of ketoconazole caused by supersaturation saturated the metabolic enzymes and further increased the systemic exposure of the absorbed drug. The additional effects of supersaturation on the absorption of ketoconazole are consistent with previous studies in humans under differing gastric pH conditions. In conclusion, effects of supersaturation on

  6. One-step preparation of drug-containing microparticles to enhance the dissolution and absorption of poorly water-soluble drugs using a 4-fluid nozzle spray drier.

    PubMed

    Mizoe, Takuto; Beppu, Shuji; Ozeki, Tetsuya; Okada, Hiroaki

    2007-07-31

    We studied the use of a 4-fluid nozzle spray drier as a new one-step method for preparing drug-containing microparticles to enhance the dissolution and absorption of poorly water-soluble drugs. We employed ethenzamide (EZ) and flurbiprofen (FP) as poorly water-soluble drugs and lactose (LAC) and mannitol (MAN) as water-soluble carriers for microparticles. EZ-ethanol or FP-acetone/methanol (2:1) solutions and aqueous solutions of LAC or MAN were simultaneously supplied through different liquid passages of a 4-fluid nozzle spray drier and then dried to obtain LAC or MAN microparticles containing EZ or FP. The dissolution of EZ from the EZ/LAC and EZ/MAN microparticles was much faster than that from EZ powder. The dissolution of EZ was more rapid from the EZ/MAN microparticles than the EZ/LAC microparticles. The dissolution of FP from the FP/MAN microparticles was greatly enhanced because of large effective surface area of FP dispersed in microparticles following rapid dissolution of MAN. The absorption of FP after oral administration of the FP/MAN microparticles to rats was markedly increased. The results demonstrate that the 4-fluid nozzle spray drier can be used for the one-step preparation of drug-containing microparticles that enhance the dissolution and absorption of poorly water-soluble drugs and that overcome the problem of finding a common solvent for drugs and carriers. PMID:17582644

  7. The absorption spectrum of water vapor in the 1.25 μm atmospheric window (7911-8337 cm-1)

    NASA Astrophysics Data System (ADS)

    Campargue, A.; Mikhailenko, S. N.; Lohan, Benoit Guillo; Karlovets, E. V.; Mondelain, D.; Kassi, S.

    2015-05-01

    The absorption spectrum of water vapor in "natural" isotopic abundance has been recorded at room temperature by high sensitivity Continuous Wave Cavity Ring Down Spectroscopy (CW-CRDS) between 7911 and 8337 cm-1. The investigated region covers most of the 1.25 μm transparency window of importance for atmospheric applications. The recordings were performed with sensitivity on the order of αmin~2×10-11 cm-1, more than two orders of magnitude better than previous investigations by Fourier Transform Spectroscopy (FTS). Measured line intensities cover a range of seven orders of magnitude (3×10-30-2×10-23 cm/molecule at room temperature). The experimental line list provided as Supplementary Material includes more than 5000 transitions. As a result of the achieved sensitivity, more than 1150 lines of the experimental list were identified as being due to ammonia present as an impurity at the 5 ppm concentration level in the water sample. Although incomplete, the obtained ammonia line list seems to be the first one in the region. More than 3193 water lines were assigned to 3560 transitions of five water isotopologues (H216O, H218O, H217O, HD16O and HD18O). The assignments were performed using known experimental energy levels and calculated spectra based on variational calculations by Schwenke and Partridge. The obtained results are compared to the most relevant previous studies by Fourier Transform Spectroscopy in the region and to the exhaustive review of rovibrational line positions and levels performed recently by an IUPAC sponsored task group. Two-hundred and sixty-six levels are newly determined and 46 are corrected by more than 0.015 cm-1 compared to those recommended by the water IUPAC task group. The overall agreement between variational and measured intensities is satisfactory. A complete empirical list of 4473 transitions incorporating all the experimental information at disposal was constructed for water in the studied region. The intensity cut-off was fixed

  8. A modified physiological BCS for prediction of intestinal absorption in drug discovery.

    PubMed

    Zaki, Noha M; Artursson, Per; Bergström, Christel A S

    2010-10-01

    In this study, the influence of physiologically relevant media on the compound position in a biopharmaceutical classification system (BCS) which resembled the intestinal absorption was investigated. Both solubility and permeability limited compounds (n = 22) were included to analyze the importance of each of these on the final absorption. Solubility was determined in three different dissolution media, phosphate buffer pH 6.5 (PhB 6.5), fasted state simulated intestinal fluid (FaSSIF), and fed state simulated intestinal fluid (FeSSIF) at 37 °C, and permeability values were determined using the 2/4/A1 cell line. The solubility data and membrane permeability values were used for sorting the compounds into a BCS modified to reflect the fasted and fed state. Three of the seven compounds sorted as BCS II in PhB 6.5 (high permeability, low solubility) changed their position to BCS I when dissolved in FaSSIF and/or FeSSIF (high permeability, high solubility). These were low dosed (20 mg or less) lipophilic molecules displaying solvation limited solubility. In contrast, compounds having solid-state limited solubility had a minor increase in solubility when dissolved in FaSSIF and/or FeSSIF. Although further studies are needed to enable general cutoff values, our study indicates that low dosed BCS Class II compounds which have solubility normally restricted by poor solvation may behave as BCS Class I compounds in vivo. The large series of compounds investigated herein reveals the importance of investigating solubility and dissolution under physiologically relevant conditions in all stages of the drug discovery process to push suitable compounds forward, to select proper formulations, and to reduce the risk of food effects. PMID:20734997

  9. Effects of PEGylated lipid nanoparticles on the oral absorption of one BCS II drug: a mechanistic investigation

    PubMed Central

    Zhang, Xingwang; Chen, Guijiang; Zhang, Tianpeng; Ma, Zhiguo; Wu, Baojian

    2014-01-01

    Lipid nanocarriers are becoming a versatile platform for oral delivery of lipophilic drugs. In this article, we aimed to explore the gastrointestinal behaviors of lipid nanoparticles and the effect of PEGylation on oral absorption of fenofibrate (FN), a Biopharmaceutics Classification System (BCS) II model drug. FN-loaded PEGylated lipid nanoparticles (FN-PLNs) were prepared by the solvent-diffusion method and characterized by particle size distribution, morphology, Fourier transform infrared spectroscopy, and drug release. Lipolytic experiments were performed to assess the resistance of lipid nanoparticles against pancreatic lipase. Pharmacokinetics was evaluated in rats after oral administration of FN preparations. The obtained FN-PLNs were 186.7 nm in size with an entrapment efficiency of >95%. Compared to conventional lipid nanoparticles, PLNs exhibited slower drug release in the lipase-containing medium, strikingly reduced mucin binding, and suppressed lipolysis in vitro. Further, oral absorption of FN was significantly enhanced using PLNs with relative bioavailability of 123.9% and 157.0% to conventional lipid nanoparticles and a commercial formulation (Lipanthyl®), respectively. It was demonstrated that reduced mucin trapping, suppressed lipolysis, and/or improved mucosal permeability were responsible for increased oral absorption. These results facilitated a better understanding of the in vivo fate of lipid nanoparticles, and suggested the potential of PLNs as oral carriers of BCS II drugs. PMID:25473287

  10. Evaluating Potential P-gp Substrates: Main Aspects to Choose the Adequate Permeability Model for Assessing Gastrointestinal Drug Absorption.

    PubMed

    da Silva Junior, João Batista; Dezani, Thaisa Marinho; Dezani, André Bersani; dos Reis Serra, Cristina Helena

    2015-01-01

    The success of an oral drug route administration depends on many factors that interfere in its bioavailability, therapeutic efficacy and clinical safety. In human cells, ATP-dependent efflux transporter proteins, such as P-glycoprotein (P-gp), BCRP and MRP2, reduce the absorption of drugs. A tiered approach chosen to evaluate drugs as substrates or inhibitors of efflux pumps, particularly P-gp, should be carefully selected, since each study method has advantages and intrinsic limitations to their processes. Depending on the adopted study conditions, the results may not correspond to the real characteristics of the drug regarding to its modulation by specific efflux proteins. This mini-review aims at summarizing the role of P-gp in the drugs oral absorption and correlating some of the most used permeability methods to determine the drug condition as P-gp substrate. Studies about P-gp have shown that it is a dynamic protein, facilitating secretion of endogenous compounds, as aldosterone, and protecting cells against xenobiotics. Different efflux assays are employed to evaluate drugs as P-gp substrates. In an initial planning, MDCK-MDR1 tend to be the chosen method for efflux studies due its ability of express P-gp, followed by studies conducted in Caco-2 models. However, it is necessary to evaluate the advantages and disadvantages of each method to generate sound results and to set the correlation in vitro x in situ x in vivo. PMID:25963568

  11. Anticancer efficacy and absorption, distribution, metabolism, and toxicity studies of Aspergiolide A in early drug development

    PubMed Central

    Wang, Yuanyuan; Qi, Xin; Li, Dehai; Zhu, Tianjiao; Mo, Xiaomei; Li, Jing

    2014-01-01

    Since the first anthracycline was discovered, many other related compounds have been studied in order to overcome its defects and improve efficacy. In the present paper, we investigated the anticancer effects of a new anthracycline, aspergiolide A (ASP-A), from a marine-derived fungus in vitro and in vivo, and we evaluated the absorption, distribution, metabolism, and toxicity drug properties in early drug development. We found that ASP-A had activity against topoisomerase II that was comparable to adriamycin. ASP-A decreased the growth of various human cancer cells in vitro and induced apoptosis in BEL-7402 cells via a caspase-dependent pathway. The anticancer efficacy of ASP-A on the growth of hepatocellular carcinoma xenografts was further assessed in vivo. Results showed that, compared with the vehicle group, ASP-A exhibited significant anticancer activity with less loss of body weight. A pharmacokinetics and tissue distribution study revealed that ASP-A was rapidly cleared in a first order reaction kinetics manner, and was enriched in cancer tissue. The maximal tolerable dose (MTD) of ASP-A was more than 400 mg/kg, and ASP-A was not considered to be potentially genotoxic or cardiotoxic, as no significant increase of micronucleus rates or inhibition of the hERG channel was seen. Finally, an uptake and transport assay of ASP-A was performed in monolayers of Caco-2 cells, and ASP-A was shown to be absorbed through the active transport pathway. Altogether, these results indicate that ASP-A has anticancer activity targeting topoisomerase II, with a similar structure and mechanism to adriamycin, but with much lower toxicity. Nonetheless, further molecular structure optimization is necessary. PMID:25378909

  12. Novel oral formulation safely improving intestinal absorption of poorly absorbable drugs: utilization of polyamines and bile acids.

    PubMed

    Miyake, Masateru; Minami, Takanori; Hirota, Masao; Toguchi, Hajime; Odomi, Masaaki; Ogawara, Ken-ichi; Higaki, Kazutaka; Kimura, Toshikiro

    2006-03-10

    In order to develop a novel oral formulation that can safely improve the intestinal absorption of poorly absorbable drugs, polyamines such as spermine (SPM) and spermidine (SPD) was examined as an absorption enhancing adjuvant in rats. The absorption of rebamipide, classified into BCS Class IV, from colon was significantly improved by SPM or SPD, and the enhancing ability of SPM was larger than that of SPD. As a possible mixing and/or interaction of polyamines with bile acids were expected, the combinatorial use of sodium taurocholate (STC) with polyamines was also examined. The absorption of rebamipide was drastically improved by the combinatorial use of SPM or SPD with STC. As STC itself did not enhance the absorption of rebamipide so much, it was considered that polyamines and STC had a synergistic enhancing effect. In-vivo oral absorption study was also performed to investigate the effectiveness and safety of polyamines and their combinatorial use with STC in rats. Although the enhancing effect slightly attenuated comparing with the in-situ loop study, the absorption of rebamipide was significantly improved and the combinatorial use of 10 mM SPM with 25 mM STC showed the largest enhancing effect. Histopathological studies clearly showed that any significant change in stomach and duodenum was not caused by SPM (10 mM), SPD (10 mM) or their combinatorial use with STC (25 mM) at 1.5 or 8.0 h after oral administration. Taken all together, polyamines, especially SPM, and its combinatorial use with STC could improve the absorption of poorly absorbable drugs without any significant changes in gastrointestinal tract after oral administration in rats. PMID:16410031

  13. Tracking Drug Loading Capacities of Calcium Silicate Hydrate Carrier: A Comparative X-ray Absorption Near Edge Structures Study.

    PubMed

    Guo, Xiaoxuan; Wang, Zhiqiang; Wu, Jin; Yiu, Yun-Mui; Hu, Yongfeng; Zhu, Ying-Jie; Sham, Tsun-Kong

    2015-08-01

    Mesoporous spheres of calcium silicate hydrate (MS-CSH) have been prepared by an ultrasonic method. Following an earlier work in which we have revealed the interactions between ibuprofen (IBU) and CSH carriers with different morphologies by X-ray absorption near edge structures (XANES) analysis. In the present investigation, two new drug molecules, alendronate sodium (ALN) and gentamicin sulfate (GS), were incorporated into MS-CSH, and their drug loading capacities (DLCs) were measured using thermogravimetric analysis to establish the relationship between drug-carrier interactions and DLCs. The XANES spectra clearly indicate that acidic functional groups of the drug molecules linked to the active sites (Ca-OH and Si-OH groups) of MS-CSH on the surface by electrostatic interactions. In addition, it is found that the stoichiometric ratio of Ca(2+) ions of CSH carriers and the functional groups of drug molecules may significantly influence the DLCs. PMID:26162602

  14. CAVE WINDOW

    DOEpatents

    Levenson, M.

    1960-10-25

    A cave window is described. It is constructed of thick glass panes arranged so that interior panes have smaller windowpane areas and exterior panes have larger areas. Exterior panes on the radiation exposure side are remotely replaceable when darkened excessively. Metal shutters minimize exposure time to extend window life.

  15. Interaction of the main components from the traditional Chinese drug pair Chaihu-Shaoyao based on rat intestinal absorption.

    PubMed

    Chen, Yan; Wang, Jinyan; Yuan, Ling; Zhou, Lei; Jia, Xiaobin; Tan, Xiaobin

    2011-01-01

    The Chaihu-Shaoyao drug pair (Bupleuri Radix and Paeoniae Radix Alba) which is a traditional Chinese drug pair, has been widely used for anti-inflammatory purposes. Saikosaponin a (SSA), saikosaponin d (SSD) and paeoniflorin are identified as the main components in the pair. The present study focused on the interaction of the main components based on investigating their intestinal absorption using a four-site perfused rat intestinal model in order to clarify the mechanism of the compatibility of Chaihu-Shaoyao. The concentrations of SSA, SSD and paeoniflorin in the intestinal perfusate were determined by LC/MS or UPLC (Ultra Performance Liquid Chromatography) methods, followed by P*(eff) (effective permeability) and 10% ABS (the percent absorption of 10 cm of intestine) calculations. The results showed that all of the three main components displayed very low permeabilities (P*(eff) < 0.4), which implied their poor absorption in the rat intestine. The absorption levels of SSA and SSD were similar in intestine and higher in ileum than those in other intestinal regions in the decreasing order: colon, jejunum and duodenum. However, there is no significant difference in the absorption of paeoniflorin in the four segments (P < 0.05). The P*(eff) values of paeoniflorin exhibited an almost 2.11-fold or 1.90-fold increase in ileum when it was co-administrated with SSA and SSD, as well as 2.42-, 2.18-fold increase in colon, respectively, whereas the absorptions of SSA and SSD were not influenced by paeoniflorin. In conclusion, SSA and SSD could promote the absorption of paeoniflorin. To some extent this might explain the nature of the compatibility mechanisms of composite formulae in TCMs. PMID:22095024

  16. Impact of Luminal Fluid Volume on the Drug Absorption After Oral Administration: Analysis Based on In Vivo Drug Concentration-Time Profile in the Gastrointestinal Tract.

    PubMed

    Tanaka, Yusuke; Goto, Takanori; Kataoka, Makoto; Sakuma, Shinji; Yamashita, Shinji

    2015-09-01

    The objective of this study is to clarify the influence of fluid volume in the gastrointestinal (GI) tract on the oral drug absorption. In vivo rat luminal concentrations of FITC-dextran (FD-4), a nonabsorbable marker, and drugs (metoprolol and atenolol) after oral coadministration as solutions with different osmolarity were determined by direct sampling of residual water in each segment of the GI tract. The luminal FD-4 concentration after oral administration as hyposmotic solution was significantly higher than that after administration as isosmotic or hyperosmotic solution. As the change in FD-4 concentration reflects the change in the volume of luminal fluid, it indicated that the luminal volume was greatly influenced by osmolality of solution ingested orally. Then, fraction of drug absorbed (Fa) in these segments was calculated by comparing the area under the luminal concentration-time curve of FD-4 with those of drugs. Fa values of two model drugs in each GI segment decreased with increase in luminal fluid volume, and the impact of the fluid volume was marked for Fa of atenolol (a low permeable drug) than for that of metoprolol (a high permeable drug). These findings should be beneficial to assure the effectiveness and safety of oral drug therapy. PMID:25821198

  17. The influence of food on the absorption and metabolism of drugs: an update.

    PubMed

    Williams, L; Hill, D P; Davis, J A; Lowenthal, D T

    1996-01-01

    Food-drug interactions can lead to a loss of therapeutic efficacy or toxic effects of drug therapy. Generally, the effect of food on drugs results in a reduction in the drug's bioavailability; however, food can also alter drug clearance. The benefits of considering metabolism and pharmacokinetic information in the drug discovery process have been highlighted by Humphrey and Smith (79) and the process of rational drug design should include considerations of the chemistry, pharmacology and pharmacokinetics of the drug (80) and the impact of diet on these parameters. PMID:8980916

  18. Preclinical dose number and its application in understanding drug absorption risk and formulation design for preclinical species.

    PubMed

    Wuelfing, W Peter; Daublain, Pierre; Kesisoglou, Filippos; Templeton, Allen; McGregor, Caroline

    2015-04-01

    In the drug discovery setting, the ability to rapidly identify drug absorption risk in preclinical species at high doses from easily measured physical properties is desired. This is due to the large number of molecules being evaluated and their high attrition rate, which make resource-intensive in vitro and in silico evaluation unattractive. High-dose in vivo data from rat, dog, and monkey are analyzed here, using a preclinical dose number (PDo) concept based on the dose number described by Amidon and other authors (Pharm. Res., 1993, 10, 264-270). PDo, as described in this article, is simply calculated as dose (mg/kg) divided by compound solubility in FaSSIF (mg/mL) and approximates the volume of biorelevant media per kilogram of animal that would be needed to fully dissolve the dose. High PDo values were found to be predictive of difficulty in achieving drug exposure (AUC)-dose proportionality in in vivo studies, as could be expected; however, this work analyzes a large data set (>900 data points) and provides quantitative guidance to identify drug absorption risk in preclinical species based on a single solubility measurement commonly carried out in drug discovery. Above the PDo values defined, >50% of all in vivo studies exhibited poor AUC-dose proportionality in rat, dog, and monkey, and these values can be utilized as general guidelines in discovery and early development to rapidly assess risk of solubility-limited absorption for a given compound. A preclinical dose number generated by biorelevant dilutions of formulated compounds (formulated PDo) was also evaluated and defines solubility targets predictive of suitable AUC-dose proportionality in formulation development efforts. Application of these guidelines can serve to efficiently identify compounds in discovery that are likely to present extreme challenges with respect to solubility-limited absorption in preclinical species as well as reduce the testing of poor formulations in vivo, which is a key

  19. Rapid screening and identification of illicit drugs by IR absorption spectroscopy and gas chromatography

    NASA Astrophysics Data System (ADS)

    Mengali, Sandro; Liberatore, Nicola; Luciani, Domenico; Viola, Roberto; Cardinali, Gian Carlo; Elmi, Ivan; Poggi, Antonella; Zampolli, Stefano; Biavardi, Elisa; Dalcanale, Enrico; Bonadio, Federica; Delemont, Olivier; Esseiva, Pierre; Romolo, Francesco S.

    2013-01-01

    Analytical instruments based on InfraRed Absorption Spectroscopy (IRAS) and Gas Chromatography (GC) are today available only as bench-top instrumentation for forensic labs and bulk analysis. Within the 'DIRAC' project funded by the European Commission, we are developing an advanced portable sensor, that combines miniaturized GC as its key chemical separation tool, and IRAS in a Hollow Fiber (HF) as its key analytical tool, to detect and recognize illicit drugs and key precursors, as bulk and as traces. The HF-IRAS module essentially consists of a broadly tunable External Cavity (EC) Quantum Cascade Laser (QCL), thermo-electrically cooled MCT detectors, and an infrared hollow fiber at controlled temperature. The hollow fiber works as a miniaturized gas cell, that can be connected to the output of the GC column with minimal dead volumes. Indeed, the module has been coupled to GC columns of different internal diameter and stationary phase, and with a Vapour Phase Pre-concentrator (VPC) that selectively traps target chemicals from the air. The presentation will report the results of tests made with amphetamines and precursors, as pure substances, mixtures, and solutions. It will show that the sensor is capable of analyzing all the chemicals of interest, with limits of detection ranging from a few nanograms to about 100-200 ng. Furthermore, it is suitable to deal with vapours directly trapped from the headspace of a vessel, and with salts treated in a basic solution. When coupled to FAST GC columns, the module can analyze multi-components mixes in less than 5 minutes.

  20. Paracetamol as a Post Prandial Marker for Gastric Emptying, A Food-Drug Interaction on Absorption

    PubMed Central

    Bartholomé, R.; Salden, B.; Vrolijk, M. F.; Troost, F. J.; Masclee, A.; Bast, A.; Haenen, G. R.

    2015-01-01

    The use of paracetamol as tool to determine gastric emptying was evaluated in a cross over study. Twelve healthy volunteers were included and each of them consumed two low and two high caloric meals. Paracetamol was mixed with a liquid meal and administered by a nasogastric feeding tube. The post prandial paracetamol plasma concentration time curve in all participants and the paracetamol concentration in the stomach content in six participants were determined. It was found that after paracetamol has left the stomach, based on analysis of the stomach content, there was still a substantial rise in the plasma paracetamol concentration time curve. Moreover, the difference in gastric emptying between high and low caloric meals was missed using the plasma paracetamol concentration time curve. The latter curves indicate that (i) part of the paracetamol may leave the stomach much quicker than the meal and (ii) part of the paracetamol may be relatively slowly absorbed in the duodenum. This can be explained by the partition of the homogenous paracetamol-meal mixture in the stomach in an aqueous phase and a solid bolus. The aqueous phase leaves the stomach quickly and the paracetamol in this phase is quickly absorbed in the duodenum, giving rise to the relatively steep increase of the paracetamol concentration in the plasma. The bolus leaves the stomach relatively slowly, and encapsulation by the bolus results in relatively slow uptake of paracetamol from the bolus in the duodenum. These findings implicate that paracetamol is not an accurate post prandial marker for gastric emptying. The paracetamol concentration time curve rather illustrates the food-drug interaction on absorption, which is not only governed by gastric emptying. Trial Registration ClinicalTrials.gov NCT01335503 Nederlands Trial Register NTR2780 PMID:26352940

  1. Nanostructure of liquid crystalline matrix determines in vitro sustained release and in vivo oral absorption kinetics for hydrophilic model drugs.

    PubMed

    Lee, Kathy W Y; Nguyen, Tri-Hung; Hanley, Tracey; Boyd, Ben J

    2009-01-01

    Nanostructured lipid-based liquid crystalline systems have been proposed as sustained oral drug delivery systems, but the interplay between their intrinsic release rates, susceptibility to digestive processes, and the manner in which these effects impact on their application in vivo, are not well understood. In this study, two different bicontinuous cubic phases, prepared from glyceryl monooleate and phytantriol, and a reversed hexagonal phase formed by addition of a small amount of vitamin E to phytantriol (Q(II GMO), Q(II PHYT) and H(II PHYT+VitEA), respectively) were prepared. The release kinetics for a number of model hydrophilic drugs with increasing molecular weights (glucose, Allura Red and FITC-dextrans) was determined in in vitro release experiments. Diffusion-controlled release was observed in all cases as anticipated from previous studies with liquid crystalline systems, and it was discovered that the release rates of each drug decreased as the matrix was changed from Q(II GMO) to Q(II PHYT) to H(II PHYT+VitEA). Formulations containing (14)C-glucose, utilized as a rapidly absorbed marker of drug release, were then orally administered to rats to determine the relative in vivo absorption rates from the different formulations. The results showed a trend by which the rate of absorption of (14)C-glucose followed that observed in the corresponding in vitro release studies, providing the first indication that the nanostructure of these materials may provide the ability to tailor the absorption kinetics of hydrophilic drugs in vivo, and hence form the basis of a new drug delivery system. PMID:18790030

  2. Erbium:YAG laser resurfacing increases skin permeability and the risk of excessive absorption of antibiotics and sunscreens: the influence of skin recovery on drug absorption.

    PubMed

    Lee, Woan-Ruoh; Shen, Shing-Chuan; Al-Suwayeh, Saleh A; Li, Yi-Ching; Fang, Jia-You

    2012-06-01

    While laser skin resurfacing is expected to result in reduced barrier function and increased risk of drug absorption, the extent of the increment has not yet been systematically investigated. We aimed to establish the skin permeation profiles of tetracycline and sunscreens after exposure to the erbium:yttrium-aluminum-garnet (Er:YAG) laser during postoperative periods. Physiological and histopathological examinations were carried out for 5 days after laser treatment on nude mice. Percutaneous absorption of the permeants was determined by an in vitro Franz cell. Ablation depths varied in reaching the stratum corneum (10 μm, 2.5 J/cm²) to approach the epidermis (25 μm, 6.25 J/cm²) and upper dermis (40 μm, 10 J/cm²). Reepithelialization evaluated by transepidermal water loss was complete within 2-4 days and depended on the ablation depth. Epidermal hyperplasia was observed in the 40-μm-treated group. The laser was sufficient to disrupt the skin barrier and allow the transport of the permeants into and across the skin. The laser fluence was found to play an important role in modulating skin absorption. A 25-μm ablation depth increased tetracycline flux 84-fold. A much smaller enhancement (3.3-fold) was detected for tetracycline accumulation within the skin. The laser with different fluences produced enhancement of oxybenzone skin deposition of 3.4-6.4-fold relative to the untreated group. No penetration across the skin was shown regardless of whether titanium dioxide was applied to intact or laser-treated skin. However, laser resurfacing increased the skin deposition of titanium dioxide from 46 to 109-188 ng/g. Tetracycline absorption had recovered to the level of intact skin after 5 days, while more time was required for oxybenzone absorption. The in vivo skin accumulation and plasma concentration revealed that the laser could increase tetracycline absorption 2-3-fold. The experimental results indicated that clinicians should be cautious when determining the

  3. Physiologically Based In vitro Models to Predict the Oral Dissolution and Absorption of a Solid Drug Delivery System.

    PubMed

    Li, Ziqiang; He, Xin

    2015-01-01

    To understand the sophisticated dynamic behaviors of drug elution and permeation in the gastrointestinal tract (GIT), researchers have tried to reemerge it by employing various in vitro experimental models. However, official in vitro apparatuses routinely used for quality control purposes, employ simple, non-physiologic buffers, and hydrodynamics conditions, and can not accurately perform continuous, dynamic in vivo pharmacokinetics (PK) behaviors. Therefore, different angles of GI physiology information are incorporate into novel models to forecast the dissolution and permeation of drug solid dosage forms. This review, in general, discusses some related studies of physiologically-based mechanical models to predict human absorption following oral administration in four sections. First the GIT, taken out of a complex physiological environment, where the drug is absorbed, distributed, metabolized and excreted (ADME) in the human body, is considered as the physiological basis for active pharmaceutics ingredients (API) dissolved and permeated through the epithelial cell. The second part embodies the theoretical foundation of in vitro models to predict human absorption and the corresponding in vitro.in vivo correlations (IVIVC). The third section summarizes physiologically based dissolution models developed recently, ranging from dynamic compartmental dissolution models, to biorelevant dissolution models based on certain physiological factors, to biphasic dissolution models. The last part is devoted to combined dissolution and absorption models that can be employed to simulate the continuous, dynamic behavior of oral drug delivery being dissolved and subsequently permeated across the GIT. Along with physiologically-based mechanically models spring up, pharmaceutical researchers will harvest better level A IVIVC for oral drug delivery systems, especially for sustained and controlled release preparations. On the other way hand, it will successively promote more effective

  4. Mechanism of enhanced oral absorption of morin by phospholipid complex based self-nanoemulsifying drug delivery system.

    PubMed

    Zhang, Jinjie; Li, Jianbo; Ju, Yuan; Fu, Yao; Gong, Tao; Zhang, Zhirong

    2015-02-01

    Phospholipid complex (PLC) based self-nanoemulsifying drug delivery system (PLC-SNEDDS) has been developed for efficient delivery of drugs with poor solubility and low permeability. In the present study, a BCS class IV drug and a P-glycoprotein (P-gp) substrate, morin, was selected as the model drug to elucidate the oral absorption mechanism of PLC-SNEDDS. PLC-SNEDDS was superior to PLC in protecting morin from degradation by intestinal enzymes in vitro. In situ perfusion study showed increased intestinal permeability by PLC was duodenum-specific. In contrast, PLC-SNEDDS increased morin permeability in all intestinal segments and induced a change in the main absorption site of morin from colon to ileum. Moreover, ileum conducted the lymphatic transport of PLC-SNEDDS, which was proven by microscopic intestinal visualization of Nile red labeled PLC-SNEDDS and lymph fluids in vivo. Low cytotoxicity and increased Caco-2 cell uptake suggested a safe and efficient delivery of PLC-SNEDDS. The increased membrane fluidity and disrupted actin filaments were closely associated with the increased cell uptake of PLC-SNEDDS. PLC-SNEDDS could be internalized into enterocytes as an intact form in a cholesterol-dependent manner via clathrin-mediated endocytosis and macropinocytosis. The enhanced oral absorption of morin was attributed to the P-gp inhibition by Cremophor RH and the intact internalization of M-PLC-SNEDDS into Caco-2 cells bypassing P-gp recognition. Our findings thus provide new insights into the development of novel nanoemulsions for poorly absorbed drugs. PMID:25536306

  5. Interplay of metabolism and transport in determining oral drug absorption and gut wall metabolism: a simulation assessment using the "Advanced Dissolution, Absorption, Metabolism (ADAM)" model.

    PubMed

    Darwich, A S; Neuhoff, S; Jamei, M; Rostami-Hodjegan, A

    2010-11-01

    Bioavailability of orally administered drugs can be influenced by a number of factors including release from the formulation, dissolution, stability in the gastrointestinal (GI) environment, permeability through the gut wall and first-pass gut wall and hepatic metabolism. Although there are various enzymes in the gut wall which may contribute to gut first pass metabolism, Cytochrome P450 (CYP) 3A has been shown to play a major role. The efflux transporter P-glycoprotein (P-gp; MDR1/ABCB1) is the most extensively studied drug efflux transporter in the gut and might have a significant role in the regulation of GI absorption. Although not every CYP3A substrate will have a high extent of gut wall first-pass extraction, being a substrate for the enzyme increases the likelihood of a higher first-pass extraction. Similarly, being a P-gp substrate does not necessarily pose a problem with the gut wall absorption however it may reduce bioavailability in some cases (e.g. when drug has low passive permeability). An on-going debate has focused on the issue of the interplay between CYP3A and P-gp such that high affinity to P-gp increases the exposure of drug to CYP3A through repeated cycling via passive diffusion and active efflux, decreasing the fraction of drug that escapes first pass gut metabolism (F(G)). The presence of P-gp in the gut wall and the high affinity of some CYP3A substrates to this transporter are postulated to reduce the potential for saturating the enzymes, thus increasing gut wall first-pass metabolism for compounds which otherwise would have saturated CYP3A. Such inferences are based on assumptions in the modelling of oral drug absorption. These models should be as mechanistic as possible and tractable using available in vitro and in vivo information. We review, through simulation, this subject and examine the interplay between gut wall metabolism and efflux transporters by studying the fraction of dose absorbed into enterocytes (F(a)) and F(G) via

  6. A Comparative Study of Molecular Structure, pKa, Lipophilicity, Solubility, Absorption and Polar Surface Area of Some Antiplatelet Drugs

    PubMed Central

    Remko, Milan; Remková, Anna; Broer, Ria

    2016-01-01

    Theoretical chemistry methods have been used to study the molecular properties of antiplatelet agents (ticlopidine, clopidogrel, prasugrel, elinogrel, ticagrelor and cangrelor) and several thiol-containing active metabolites. The geometries and energies of most stable conformers of these drugs have been computed at the Becke3LYP/6-311++G(d,p) level of density functional theory. Computed dissociation constants show that the active metabolites of prodrugs (ticlopidine, clopidogrel and prasugrel) and drugs elinogrel and cangrelor are completely ionized at pH 7.4. Both ticagrelor and its active metabolite are present at pH = 7.4 in neutral undissociated form. The thienopyridine prodrugs ticlopidine, clopidogrel and prasugrel are lipophilic and insoluble in water. Their lipophilicity is very high (about 2.5–3.5 logP values). The polar surface area, with regard to the structurally-heterogeneous character of these antiplatelet drugs, is from very large interval of values of 3–255 Å2. Thienopyridine prodrugs, like ticlopidine, clopidogrel and prasugrel, with the lowest polar surface area (PSA) values, exhibit the largest absorption. A high value of polar surface area (PSA) of cangrelor (255 Å2) results in substantial worsening of the absorption in comparison with thienopyridine drugs. PMID:27007371

  7. Improved oral absorption of dutasteride via Soluplus®-based supersaturable self-emulsifying drug delivery system (S-SEDDS).

    PubMed

    Lee, Dong Hoon; Yeom, Dong Woo; Song, Ye Seul; Cho, Ha Ra; Choi, Yong Seok; Kang, Myung Joo; Choi, Young Wook

    2015-01-15

    A novel supersaturable self-emulsifying drug delivery system (S-SEDDS) was formulated to improve the oral absorption of dutasteride (DTS), a 5α-reductase inhibitor that is poorly water-soluble. A supersaturable system was prepared by employing Soluplus(®) (polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer) as a precipitation inhibitor with a conventional SEDDS vehicle consisted of Capryol™ 90, Cremophor(®) EL and Transcutol(®) HP (DTS:SEDDS vehicle:Soluplus(®)=1.0:67.6:10.0 w/v/w). In an in vitro dissolution test in a non-sink condition, the drug dissolution rate from SEDDS was rapidly increased to 72% for an initial period of 5min, but underwent rapid drug precipitation within 2h, decreasing the amount of drug dissolved to one-seventh of its original amount. On the other hand, S-SEDDS resulted in a slower crystallization of DTS by virtue of a precipitation inhibitor, maintaining a 3 times greater dissolution rate after 2h compared to SEDDS. In an in vivo pharmacokinetic study in rats, the S-SEDDS formulation exhibited 3.9-fold greater area-under-curve value than that of the drug suspension and 1.3-fold greater than that of SEDDS. The maximum plasma concentration of S-SEDDS was 5.6- and 2.0-fold higher compared to drug suspension and SEDDS, respectively. The results of this study suggest that the novel supersaturable system may be a promising tool for improving the physicochemical property and oral absorption of the 5α-reductase inhibitor. PMID:25437113

  8. Physiologically Based Absorption Modeling to Impact Biopharmaceutics and Formulation Strategies in Drug Development-Industry Case Studies.

    PubMed

    Kesisoglou, Filippos; Chung, John; van Asperen, Judith; Heimbach, Tycho

    2016-09-01

    In recent years, there has been a significant increase in use of physiologically based pharmacokinetic models in drug development and regulatory applications. Although most of the published examples have focused on aspects such as first-in-human (FIH) dose predictions or drug-drug interactions, several publications have highlighted the application of these models in the biopharmaceutics field and their use to inform formulation development. In this report, we present 5 case studies of use of such models in this biopharmaceutics/formulation space across different pharmaceutical companies. The case studies cover different aspects of biopharmaceutics or formulation questions including (1) prediction of absorption prior to FIH studies; (2) optimization of formulation and dissolution method post-FIH data; (3) early exploration of a modified-release formulation; (4) addressing bridging questions for late-stage formulation changes; and (5) prediction of pharmacokinetics in the fed state for a Biopharmaceutics Classification System class I drug with fasted state data. The discussion of the case studies focuses on how such models can facilitate decisions and biopharmaceutic understanding of drug candidates and the opportunities for increased use and acceptance of such models in drug development and regulatory interactions. PMID:26886317

  9. Influence of Circulation System on Estimation of Absorption and Elimination Constant after per oral Drug Administration: A Reanalysis.

    PubMed

    Rausova, Z; Chrenova, J; Dedik, L

    2013-03-01

    This study aimed to identify the cause of atypical shape of measured concentration-time profile in the peak area by one compartment open model with a lag time (Bateman function with a lag) after single dose oral administration of drug published in "Pharmacokinetic and Pharmacodynamic Data Analysis: Concepts and Application" by Gabrielsson and Weiner (1997) and two concentration profiles after frequent sampling oral glucose tolerance test. Following the oral administration of 100 μg of substance A to human volunteer, frequent sampling was carried out and concentration-time profiles were obtained. Our hemodynamic circulatory structural model capable of parameters estimation of circulation and gastrointestinal subsystem to explain the plateau within the interval 40-100 min (substance A) and 15-30 min (glucose) of the measured concentration-time profile was developed. The mean residence time, the rate constants of absorption and elimination parameters of our model were calculated. Comparing to the Bateman function, our results demonstrate better approximation of the substance A and glucose concentration-time profile and estimation of absorption rate constant by our structural model. Obtained model results indicate that the atypical shape of measured concentration-time profile of single dose oral administration of drug was probably caused by the gastrointestinal and circulation system with deep compartment. This applies to the substances with high coefficient of absorption. PMID:24019565

  10. In situ intestinal permeability and in vivo absorption characteristics of olmesartan medoxomil in self-microemulsifying drug delivery system.

    PubMed

    Kang, Myung J; Kim, Hyung S; Jeon, Ho S; Park, Jong H; Lee, Bong S; Ahn, Byeong K; Moon, Ki Y; Choi, Young W

    2012-05-01

    To characterize the intestinal absorption behavior of olmesartan medoxomil (OLM) and to evaluate the absorption-improving potential of a self-microemulsifying drug delivery system (SMEDDS), we performed in situ single-pass intestinal perfusion (SPIP) and in vivo pharmacokinetic studies in rats. The SPIP study revealed that OLM is absorbed throughout whole intestinal regions, favoring proximal segments, at drug levels of 10-90 μM. The greatest value for effective permeability coefficient (P(eff)) was 11.4 × 10(-6) cm/s in the duodenum (90 μM); the lowest value was 2.9 × 10(-6) cm/s in the ileum (10 μM). A SMEDDS formulation consisting of Capryol 90, Labrasol, and Transcutol, which has a droplet size of 200 nm and self-dispersion time of 21 s, doubled upper intestinal permeability of OLM. The SMEDDS also improved oral bioavailability of OLM in vivo: a 2.7-fold increase in the area under the curve (AUC) with elevated maximum plasma concentration (C(max)) and shortened peak time (T(max)) compared to an OLM suspension. A strong correlation (r(2) = 0.955) was also found between the in situ jejunal P(eff) and the in vivo AUC values. Our study illustrates that the SMEDDS formulation holds great potential as an alternative to increased oral absorption of OLM. PMID:21988221

  11. Evaluation of different partial AUCs as indirect measures of rate of drug absorption in comparative pharmacokinetic studies.

    PubMed

    Duquesnoy, C; Lacey, L F; Keene, O N; Bye, A

    1998-10-01

    The performance of different partial AUCs, including partial AUC from zero to t(max) of the reference formulation (AUC(r)) and partial AUC from zero to tmax of test or reference formulation, whichever occurs earliest (AUC(e), as indirect measures of rate of absorption have been evaluated using simulated experiments. The performance of these metrics relative to C(max), t(max) and C(max)/AUC(infinity) was further assessed using the results of actual studies involving a Glaxo drug. The normalised metrics AUC(r)/AUC(infinity) and AUC(e)/AUC(infinity) have also been evaluated. Our provisional conclusions were: (1) AUC(r)/AUC(infinity) and AUC(e)/AUC(infinity) had greater statistical power than C(max) and the non-normalised partial AUCs at detecting true differences in rate of absorption. Using real data, the performance of AUC(e)/AUC(infinity) was poor, however, the performance of AUC(r)/AUC(infinity) was good; (2) C(max)/AUC(infinity) was more precisely estimated than AUC(r)/AUC(infinity) or AUC(e)/AUC(infinity) and may be a superior metric for assessing absorption rates of highly variable drugs. PMID:9795077

  12. Intestinal absorption of the antiepileptic drug substance vigabatrin is altered by infant formula in vitro and in vivo.

    PubMed Central

    Nøhr, Martha Kampp; Thale, Zia I; Brodin, Birger; Hansen, Steen H; Holm, René; Nielsen, Carsten Uhd

    2014-01-01

    Vigabatrin is an antiepileptic drug substance mainly used in pediatric treatment of infantile spasms. The main source of nutrition for infants is breast milk and/or infant formula. Our hypothesis was that infant formula may affect the intestinal absorption of vigabatrin. The aim was therefore to investigate the potential effect of coadministration of infant formula with vigabatrin on the oral absorption in vitro and in vivo. The effect of vigabatrin given with an infant formula on the oral uptake and transepithelial transport was investigated in vitro in Caco-2 cells. In vivo effects of infant formula and selected amino acids on the pharmacokinetic profile of vigabatrin was investigated after oral coadministration to male Sprague–Dawley rats using acetaminophen as a marker for gastric emptying. The presence of infant formula significantly reduced the uptake rate and permeability of vigabatrin in Caco-2 cells. Oral coadministration of vigabatrin and infant formula significantly reduced Cmax and prolonged tmax of vigabatrin absorption. Ligands for the proton-coupled amino acid transporter PAT1, sarcosine, and proline/l-tryptophan had similar effects on the pharmacokinetic profile of vigabatrin. The infant formula decreased the rate of gastric emptying. Here we provide experimental evidence for an in vivo role of PAT1 in the intestinal absorption of vigabatrin. The effect of infant formula on the oral absorption of vigabatrin was found to be due to delayed gastric emptying, however, it seems reasonable that infant formula may also directly affect the intestinal absorption rate of vigabatrin possibly via PAT1. PMID:25505585

  13. In Silico Prediction of Drug Dissolution and Absorption with variation in Intestinal pH for BCS Class II Weak Acid Drugs: Ibuprofen and Ketoprofen§

    PubMed Central

    Tsume, Yasuhiro; Langguth, Peter; Garcia-Arieta, Alfredo; Amidon, Gordon L.

    2012-01-01

    The FDA Biopharmaceutical Classification System guidance allows waivers for in vivo bioavailability and bioequivalence studies for immediate-release solid oral dosage forms only for BCS class I. Extensions of the in vivo biowaiver for a number of drugs in BCS Class III and BCS class II have been proposed, particularly, BCS class II weak acids. However, a discrepancy between the in vivo- BE results and in vitro- dissolution results for a BCS class II acids was recently observed. The objectives of this study were to determine the oral absorption of BCS class II weak acids via simulation software and to determine if the in vitro dissolution test with various dissolution media could be sufficient for in vitro bioequivalence studies of ibuprofen and ketoprofen as models of carboxylic acid drugs. The oral absorption of these BCS class II acids from the gastrointestinal tract was predicted by GastroPlus™. Ibuprofen did not satisfy the bioequivalence criteria at lower settings of intestinal pH=6.0. Further the experimental dissolution of ibuprofen tablets in the low concentration phosphate buffer at pH 6.0 (the average buffer capacity 2.2 mmol L-1/pH) was dramatically reduced compared to the dissolution in SIF (the average buffer capacity 12.6 mmol L -1/pH). Thus these predictions for oral absorption of BCS class II acids indicate that the absorption patterns largely depend on the intestinal pH and buffer strength and must be carefully considered for a bioequivalence test. Simulation software may be very useful tool to aid the selection of dissolution media that may be useful in setting an in vitro bioequivalence dissolution standard. PMID:22815122

  14. Forensic Identification of Automobile Window Glass Manufacturers in Japan Based on the Refractive Index, X-ray Fluorescence, and X-ray Absorption Fine Structure.

    PubMed

    Funatsuki, Atsushi; Takaoka, Masaki; Shiota, Kenji; Kokubu, Daisuke; Suzuki, Yasuhiro

    2016-01-01

    In this study, 3 automobile window glass manufacturers were identified based on refractive index, XRF, and XAFS analyses. The samples were classified into the corresponding groups using XRF, which should be the first step for identification. Samples having different manufacturing times showed differences in the refractive index. Based on XAFS, the amplitude of the EXAFS spectra and the intensities of Fourier transforms differed between manufacturers. In the scheme for manufacturer identification proposed in this study, performing XRF and refractive index studies is the first step. The concentrations of CeO2, MgO, Al2O3, and K2O allowed us to distinguish among manufacturers. Secondly, for samples containing cerium, we discriminated between manufacturer based on the amplitude of the EXAFS spectra and the intensities of Fourier transforms. As a result, the manufacturers of the 75 samples used in this study were multilaterally identified. PMID:26860567

  15. [Aortopulmonary window].

    PubMed

    González-Marín, María Arántzazu; Jiménez-Díaz, Javier; Centeno-Jiménez, Miriam; García-Cabezas, M Ángel

    2015-01-01

    The aortopulmonary window is a rare cause of heart failure in the neonate. It must be ruled out if there are signs of pulmonary edema without the most frequent left-right shunts. We report the echocardiographic images of a newborn who was admitted with symptoms of heart failure at our institution. PMID:25698530

  16. Administration of a probiotic can change drug pharmacokinetics: effect of E. coli Nissle 1917 on amidarone absorption in rats.

    PubMed

    Matuskova, Zuzana; Anzenbacherova, Eva; Vecera, Rostislav; Tlaskalova-Hogenova, Helena; Kolar, Milan; Anzenbacher, Pavel

    2014-01-01

    The growing interest in the composition and effects of microbiota raised the question how drug pharmacokinetics could be influenced by concomitant application of probiotics. The aim of this study was to find whether probiotic E. coli strain Nissle 1917 (EcN) influences the pharmacokinetics of concomitantly taken antiarrhythmic drug amiodarone (AMI). Live bacterial suspension of probiotic EcN (or non-probiotic E. coli strain ATCC 25922) was applied orally to male Wistar rats for seven days, while a control group of rats was treated with a saline solution. On the eighth day, the amiodarone hydrochloride was administered as one single oral dose (50 mg/kg) to all rats (N = 60). After 0, 1, 2, 3, 4, 5.5, 7, 9, 14, 22, and 30 hours, blood samples were taken from the rat abdominal aorta. The plasma level of AMI and its metabolite N-desethylamiodarone (DEA) was determined using the HPLC with UV detection. Administration of EcN led to a 43% increase of AMI AUC0-30 in comparison with control samples. However, this effect was not observed if EcN was replaced by a reference non-probiotic E. coli strain. Thus, EcN administration was most probably responsible for better drug absorption from the gastrointestinal tract. Plasma levels of DEA were also increased in plasma samples from animals treated with EcN. This change was again not found in the experiment with the reference non-probiotic strain. Higher DEA levels in samples from EcN-treated rats may be explained either by better absorption of AMI and/or by an increased activity of CYP2C forms, known to participate in metabolism of this drug, after EcN administration. In this paper, it is documented that concomitantly taken probiotic EcN may modulate pharmacokinetics of a drug; in this case, it led to an increased bioavailability of AMI. PMID:24505278

  17. Water-vapor foreign-continuum absorption in the 8-12 and 3-5 μm atmospheric windows

    NASA Astrophysics Data System (ADS)

    Klimeshina, T. E.; Rodimova, O. B.

    2015-08-01

    The frequency and temperature dependence of the water vapor-nitrogen continuum in the 8-12 and 3-5 μm spectral regions obtained experimentally by CAVIAR and NIST is described with the use of the line contour constructed on the basis of asymptotic line shape theory. The parameters of the theory found from fitting the calculated values of the absorption coefficient to the pertinent experimental data enter into the expression for the classical potential describing the center-of-mass motion of interacting molecules and into the expression for the quantum potential of two interacting molecules. The frequency behavior of the line wing contours appears to depend on the band the lines of which make a major contribution to the absorption in a given spectral interval. The absorption coefficients in the wings of the band in question calculated with the line contours obtained for other bands are outside of experimental errors. The distinction in the line wing behavior may be explained by the difference in the quantum energies of molecules interacting in different vibrational states.

  18. Microarray Determination of the Expression of Drug Transporters in Humans and Animal Species Used for the Investigation of Nasal Absorption

    PubMed Central

    Al-Ghabeish, Manar; Scheetz, Todd; Assem, Mahfoud; Donovan, Maureen D.

    2015-01-01

    Purpose Mice and rats are commonly used to investigate in vivo nasal drug absorption, yet their small nasal cavities limit their use for in vitro investigations. Bovine tissue explants have been used to investigate drug transport through the nasal respiratory and olfactory mucosae, yet limited information is available regarding the similarities and differences among these animal models compared to humans. The aim of this study was to compare the presence of a number of important drug transporters in the nasal mucosa of these species. Methods DNA microarray results for nasal samples from humans, rats and mice were obtained from GenBank, while DNA microarray and RT-PCR were performed on bovine nasal explants. The drug transporters of interest include multidrug resistance, cation, anion, peptide, and nucleoside transporters. Results Each of the species (mouse, rat, cow and human) shows similar patterns of expression for most of the important drug transporters. Several transporters were highly expressed in all the species, including MRP1, OCTN2, PEPT2 and y+LAT2. Conclusion While some differences in transporter mRNA and protein expression were observed, the transporter expression patterns were quite similar among the species. The differences suggest that it is important to be aware of any specific differences in transporter expression for a given compound being investigated, yet the similarities support the continued use of these animal models during preclinical investigation of intranasally administered therapeutics. PMID:26106909

  19. Microarray Determination of the Expression of Drug Transporters in Humans and Animal Species Used for the Investigation of Nasal Absorption.

    PubMed

    Al-Ghabeish, Manar; Scheetz, Todd; Assem, Mahfoud; Donovan, Maureen D

    2015-08-01

    Mice and rats are commonly used to investigate in vivo nasal drug absorption, yet their small nasal cavities limit their use for in vitro investigations. Bovine tissue explants have been used to investigate drug transport through the nasal respiratory and olfactory mucosae, yet limited information is available regarding the similarities and differences among these animal models compared to humans. The aim of this study was to compare the presence of a number of important drug transporters in the nasal mucosa of these species. DNA microarray results for nasal samples from humans, rats, and mice were obtained from GenBank, while DNA microarray and RT-PCR were performed on bovine nasal explants. The drug transporters of interest include multidrug resistance, cation, anion, peptide, and nucleoside transporters. Each of the species (mouse, rat, cattle, and human) shows similar patterns of expression for most of the important drug transporters. Several transporters were highly expressed in all the species, including MRP1, OCTN2, PEPT2, and y+LAT2. While some differences in transporter mRNA and protein expression were observed, the transporter expression patterns were quite similar among the species. The differences suggest that it is important to be aware of any specific differences in transporter expression for a given compound being investigated, yet the similarities support the continued use of these animal models during preclinical investigation of intranasally administered therapeutics. PMID:26106909

  20. A heuristic model to quantify the impact of excess cyclodextrin on oral drug absorption from aqueous solution.

    PubMed

    Olesen, Niels Erik; Westh, Peter; Holm, René

    2016-05-01

    The intestinal drug solubilising capacity (Dtot(SC)) of a drug formulated as an aqueous cyclodextrin solution is a recently proposed quantity to predict the cyclodextrin concentration needed to fully solubilise the drug in the intestinal lumen. According to this concept, the cyclodextrin concentration in the drug product must be higher than the amount needed to solubilise the compound, due to the displacement of the drug from the cyclodextrin cavity by bile salts in the intestinal lumen. On the other hand, dosing cyclodextrin at >Dtot(SC) is expected to result in decreased free intestinal drug concentrations and thus potentially a lower fraction absorbed. In this study, data from three previous in vivo studies in rats with fixed concentrations of three compounds (danazol, cinnarizine and benzo[A]pyrene) and various cyclodextrin concentrations >Dtot(SC) were analysed. The model was developed for danazol and applied to the two other compounds. Absorption, as quantified from the area under the plasma concentration-time profile, was predicted by the model to decrease at elevated concentrations of co-administered cyclodextrin in accordance with the in vivo data. In addition, at high cyclodextrin concentrations a delay in Tmax and a decrease in Cmax were predicted, again in accordance with the experimental observations. These observations were rationalised in terms of the free intestinal drug concentration by a chemical equilibrium model for Dtot(SC). This model depends on the quantity termed the dimensionless dose concentration, Dtot(∗)=Do/Pn, given as the fraction of the permeation number (Pn) and dose number (Do). The model provides the formulation scientist with a critical quality attribute for assessing the implication of having excess cyclodextrin in an oral solution. PMID:26969263

  1. Enhancement of in-vitro drug dissolution of ketoconazole for its optimal in-vivo absorption using Nanoparticles and Solid Dispersion forms of the drug

    NASA Astrophysics Data System (ADS)

    Syed, Mohammed Irfan

    was modified to include 0.02%, 0.05% and 0.1% sodium lauryl sulfate. Here, after 2 hours, the amount of drug dissolved was calculated to be 10% from controls, 21% from solid dispersion and 36% from nanoparticles in SIF with 0.02% SLS. Drug release was 20% from controls, 41% from solid dispersion and 52% from nanoparticle formulation in SIF with 0.05% SLS. Whereas amount of drug released in SIF with 0.1% SLS showed 21% from the control, 62% from solid dispersion and 85% from Nanoparticles respectively. This data supports that the ketoconazole Nanoparticles and its solid-dispersion exhibit many fold increase in dissolution of the drug, which could lead to a less variable and enhanced in-vivo drug absorption profiles. In addition, the data from the Physical Characterization (DSC, XRD and FTIR) supports that there were no interaction within the ingredients occurred in Nanoparticles and solid-dispersion formulations of the drug sample. Wet Bead Milling and Hot Melt methods proved useful in developing the Nanoparticles and solid dispersion form of ketoconazole. Results from particle size analysis were in correlation with data obtained from Scanning electron Microscopy and size of the nanoparticles was below 100nm. The dissolution studies with the modified simulated intestinal fluid (SIF) exhibited several fold increase in the dissolution of the drug compared to the pure drug powder and the commercial products used as the control. Also, the results from the physical characterization studies clearly support the stability of ketoconazole in both of these formulations.

  2. Current Approaches for Absorption, Distribution, Metabolism, and Excretion Characterization of Antibody-Drug Conjugates: An Industry White Paper.

    PubMed

    Kraynov, Eugenia; Kamath, Amrita V; Walles, Markus; Tarcsa, Edit; Deslandes, Antoine; Iyer, Ramaswamy A; Datta-Mannan, Amita; Sriraman, Priya; Bairlein, Michaela; Yang, Johnny J; Barfield, Matthew; Xiao, Guangqing; Escandon, Enrique; Wang, Weirong; Rock, Dan A; Chemuturi, Nagendra V; Moore, David J

    2016-05-01

    An antibody-drug conjugate (ADC) is a unique therapeutic modality composed of a highly potent drug molecule conjugated to a monoclonal antibody. As the number of ADCs in various stages of nonclinical and clinical development has been increasing, pharmaceutical companies have been exploring diverse approaches to understanding the disposition of ADCs. To identify the key absorption, distribution, metabolism, and excretion (ADME) issues worth examining when developing an ADC and to find optimal scientifically based approaches to evaluate ADC ADME, the International Consortium for Innovation and Quality in Pharmaceutical Development launched an ADC ADME working group in early 2014. This white paper contains observations from the working group and provides an initial framework on issues and approaches to consider when evaluating the ADME of ADCs. PMID:26669328

  3. Window comparator

    NASA Technical Reports Server (NTRS)

    Black, J. M. (Inventor)

    1977-01-01

    A window comparator is described, comprising two operational amplifiers, one with two feedback circuits, each feedback circuit having a diode connected to the amplifier output and poled for forward current conduction of opposite polarity, to provide an algebraic difference between an input signal and a selected set-point voltage. Differential input terminals of the second operational amplifier were connected to the separate feedback circuits of the first operational amplifier, one input terminal to the output of one diode, and the other to the output of the other diode. A selected window-width voltage was connected through a coupling resistor to one of the input terminals of the second operational amplifier to determine when the algebraic difference of the input signal and the setpoint voltage has exceeded a predetermined tolerance after that difference has changed signs.

  4. BERKELEY LAB WINDOW

    2015-03-06

    WINDOW features include: - Microsoft Windows TM interface - algorithms for the calculation of total fenestration product U-values and Solar Heat Gain Coefficient consistent with ASHRAE SPC 142, ISO 15099, and the National Fenestration Rating Council - a Condensation Resistance Index in accordance with the NFRC 500 Standard - and integrated database of properties - imports data from other LBNL window analysis software: - Import THERM file into the Frame Library - Import records frommore » IGDB and OPtics5 into the Glass Library for the optical properties of coated and uncoated glazings, laminates, and applied films. Program Capabilities WINDOW 7.2 offers the following features: The ability to analyze products made from any combination of glazing layers, gas layers, frames, spacers, and dividers under any environmental conditions and at any tilt; The ability to model complex glazing systems such as venetian blinds and roller shades. Directly accessible libraries of window system components, (glazing systems, glazing layers, gas fills, frame and divider elements), and environmental conditions; The choice of working in English (IP), or Systeme International (SI) units; The ability to specify the dimensions and thermal properties of each frame element (header, sills, jamb, mullion) in a window; A multi-band (wavelength-by-wavelength) spectral model; A Glass Library which can access spectral data files for many common glazing materials from the Optics5database; A night-sky radiative model; A link with the DOE-2.1E and Energy Plus building energy analysis program. Performance Indices and Other Results For a user-defined fenestration system and user-defined environmental conditions, WINDOW calculates: The U-value, solar heat gain coefficient, shading coefficient, and visible transmittance for the complete window system; The U-value, solar heat gain coefficient, shading coefficient, and visible transmittance for the glazing system (center-of-glass values); The U-values of

  5. BERKELEY LAB WINDOW

    SciTech Connect

    Curcija, Dragan Charlie; Zhu, Ling; Czarnecki, Stephen; Mitchell, Robin D.; Kohler, Christian; Vidanovic, Simon V.; Huizenga, Charlie

    2015-03-06

    WINDOW features include: - Microsoft Windows TM interface - algorithms for the calculation of total fenestration product U-values and Solar Heat Gain Coefficient consistent with ASHRAE SPC 142, ISO 15099, and the National Fenestration Rating Council - a Condensation Resistance Index in accordance with the NFRC 500 Standard - and integrated database of properties - imports data from other LBNL window analysis software: - Import THERM file into the Frame Library - Import records from IGDB and OPtics5 into the Glass Library for the optical properties of coated and uncoated glazings, laminates, and applied films. Program Capabilities WINDOW 7.2 offers the following features: The ability to analyze products made from any combination of glazing layers, gas layers, frames, spacers, and dividers under any environmental conditions and at any tilt; The ability to model complex glazing systems such as venetian blinds and roller shades. Directly accessible libraries of window system components, (glazing systems, glazing layers, gas fills, frame and divider elements), and environmental conditions; The choice of working in English (IP), or Systeme International (SI) units; The ability to specify the dimensions and thermal properties of each frame element (header, sills, jamb, mullion) in a window; A multi-band (wavelength-by-wavelength) spectral model; A Glass Library which can access spectral data files for many common glazing materials from the Optics5database; A night-sky radiative model; A link with the DOE-2.1E and Energy Plus building energy analysis program. Performance Indices and Other Results For a user-defined fenestration system and user-defined environmental conditions, WINDOW calculates: The U-value, solar heat gain coefficient, shading coefficient, and visible transmittance for the complete window system; The U-value, solar heat gain coefficient, shading coefficient, and visible transmittance for the glazing system (center-of-glass values); The U-values of the

  6. Colorimetric and atomic absorption spectrometric determination of mucolytic drug ambroxol through ion-pair formation with iron and thiocyanate.

    PubMed

    Levent, Abdulkadir; Sentürk, Zühre

    2010-09-01

    Colorimetric and atomic absorption spectrometric methods have been developed for the determination of mucolytic drug Ambroxol. These procedures depend upon the reaction of iron(III) metal ion with the drug in the presence of thiocyanate ion to form stable ion-pair complex which extractable chloroform. The red-coloured complex was determined either colorimetrically at 510 nm or by indirect atomic absorption spectrometry (AAS) via the determination of the iron content in the formed complex. The optimum experimental conditions for pH, concentrations of Fe(3+) and SCN(-), shaking time, phase ratio, and the number of extractions were determined. Under the proposed conditions, linearity was obeyed in the concentration ranges 4.1x10(-6) - 5.7x10(-5) M (1.7-23.6 µg mL(-1)) using both methods, with detection limits of 4.6x10(-7) M (0.19 µg mL(-1)) for colorimetry and 1.1x10(-6) M (0.46 µg mL(-1)) for AAS. The proposed methods were applied for the determination of Ambroxol in tablet dosage forms. The results obtained were statistically analyzed and compared with those obtained by applying the high-performance liquid chromatographic method with diode-array detection. PMID:20426742

  7. A review of drug solubility in human intestinal fluids: implications for the prediction of oral absorption.

    PubMed

    Augustijns, Patrick; Wuyts, Benjamin; Hens, Bart; Annaert, Pieter; Butler, James; Brouwers, Joachim

    2014-06-16

    The purpose of this paper is to collate all recently published solubility data of orally administered drugs in human intestinal fluids (HIF) that were aspirated from the upper small intestine (duodenum and jejunum). The data set comprises in total 102 solubility values in fasted state HIF and 37 solubility values in fed state HIF, covering 59 different drugs. Despite differences in the protocol for HIF sampling and subsequent handling, this summary of HIF solubilities provides a critical reference data set to judge the value of simulated media for intestinal solubility estimation. In this regard, the review includes correlations between the reported solubilizing capacity of HIF and fasted or fed state simulated intestinal fluid (FaSSIF/FeSSIF). Correlating with HIF solubilities enables the optimal use of solubility measurements in simulated biorelevant media to obtain accurate estimates of intestinal solubility during drug development. Considering the fraction of poorly soluble new molecular entities in contemporary drug discovery, adequate prediction of intestinal solubility is critical for efficient lead optimization, early candidate profiling, and further development. PMID:23994640

  8. Assessment of In Vivo Clinical Product Performance of a Weak Basic Drug by Integration of In Vitro Dissolution Tests and Physiologically Based Absorption Modeling.

    PubMed

    Ding, Xuan; Gueorguieva, Ivelina; Wesley, James A; Burns, Lee J; Coutant, Carrie A

    2015-11-01

    Effective integration of in vitro tests and absorption modeling can greatly improve our capability in understanding, comparing, and predicting in vivo performances of clinical drug products. In this case, we used a proprietary drug candidate galunisertib to describe the procedures of designing key in vitro tests, analyzing relevant experimental and trial data, and integrating them into physiologically based absorption models to evaluate the performances of its clinical products. By simulating the preclinical study result, we estimated high in vivo permeability for the drug. Given the high sensitivity of its solubility to pH, supersaturation may play an important role in the absorption of galunisertib. Using the dynamic dissolution test, i.e., artificial stomach-duodenum (ASD) model and simulation, we concluded galunisertib in solution or tablet products could maintain supersaturation during the transit in the gastrointestinal tract (GIT). A physiologically based absorption model was established by incorporating these key inputs in the simulation of Trial 1 results of galunisertib solution. To predict the performance of three tablet products, we developed z-factor dissolution models from the multi-pH USP dissolution results and integrate them into the absorption model. The resultant biopharmaceutical models provided good prediction of the extent of absorption of all three products, but underestimated the rate of absorption of one tablet product. Leveraging the ASD result and optimization with the dissolution model, we identified the limitation of the model due to complexity of estimating the dissolution parameter z and its in vitro-in vivo correlation. PMID:26126932

  9. Generation of enterocyte-like cells from human induced pluripotent stem cells for drug absorption and metabolism studies in human small intestine

    PubMed Central

    Ozawa, Tatsuya; Takayama, Kazuo; Okamoto, Ryota; Negoro, Ryosuke; Sakurai, Fuminori; Tachibana, Masashi; Kawabata, Kenji; Mizuguchi, Hiroyuki

    2015-01-01

    Enterocytes play an important role in drug absorption and metabolism. However, a widely used enterocyte model, Caco-2 cell, has difficulty in evaluating both drug absorption and metabolism because the expression levels of some drug absorption and metabolism-related genes in these cells differ largely from those of human enterocytes. Therefore, we decided to generate the enterocyte-like cells from human induced pluripotent stem (iPS) cells (hiPS-ELCs), which are applicable to drug absorption and metabolism studies. The efficiency of enterocyte differentiation from human iPS cells was significantly improved by using EGF, SB431542, and Wnt3A, and extending the differentiation period. The gene expression levels of cytochrome P450 3A4 (CYP3A4) and peptide transporter 1 in the hiPS-ELCs were higher than those in Caco-2 cells. In addition, CYP3A4 expression in the hiPS-ELCs was induced by treatment with 1, 25-dihydroxyvitamin D3 or rifampicin, which are known to induce CYP3A4 expression, indicating that the hiPS-ELCs have CYP3A4 induction potency. Moreover, the transendothelial electrical resistance (TEER) value of the hiPS-ELC monolayer was approximately 240 Ω*cm2, suggesting that the hiPS-ELC monolayer could form a barrier. In conclusion, we succeeded in establishing an enterocyte model from human iPS cells which have potential to be applied for drug absorption and metabolism studies. PMID:26559489

  10. Non-Destructive and Discriminating Identification of Illegal Drugs by Transient Absorption Spectroscopy in the Visible and Near-IR Wavelength Range

    NASA Astrophysics Data System (ADS)

    Sato, Chie; Furube, Akihiro; Katoh, Ryuzi; Nonaka, Hidehiko; Inoue, Hiroyuki

    2008-11-01

    We have tested the possibility of identifying illegal drugs by means of nanosecond transient absorption spectroscopy with a 10-ns UV-laser pulse for the excitation light and visible-to-near-IR light for the probe light. We measured the transient absorption spectra of acetonitrile solutions of d-methamphetamine, dl-3,4-methylenedioxymethamphetamine hydrochloride (MDMA), and dl-N-methyl-1-(1,3-benzodioxol-5-yl)-2-butanamine hydrochloride (MBDB), which are illegal drugs widely consumed in Japan. Transient absorption signals of these drugs were observed between 400 and 950 nm, a range in which they are transparent in the ground state. By analyzing the spectra in terms of exponential and Gaussian functions, we could identify the drugs and discriminate them from chemical substances having similar structures. We propose that transient absorption spectroscopy will be a useful, non-destructive method of inspecting for illegal drugs, especially when they are dissolved in liquids. Such a method may even be used for drugs packed in opaque materials if it is further extended to utilize intense femtosecond laser pulses.

  11. Aminoclay-lipid hybrid composite as a novel drug carrier of fenofibrate for the enhancement of drug release and oral absorption.

    PubMed

    Yang, Liang; Shao, Yating; Han, Hyo-Kyung

    2016-01-01

    This study aimed to prepare the aminoclay-lipid hybrid composite to enhance the drug release and improve the oral bioavailability of poorly water-soluble fenofibrate. Antisolvent precipitation coupled with an immediate freeze-drying method was adopted to incorporate fenofibrate into aminoclay-lipid hybrid composite (ALC). The optimal composition of the ALC formulation was determined as the ratios of aminoclay to krill oil of 3:1 (w/w), krill oil to fenofibrate of 2:1 (w/w), and antisolvent to solvent of 6:4 (v/v). The morphological characteristics of ALC formulation were determined using scanning electron microscopy, differential scanning calorimetry, and X-ray powder diffraction, which indicated microcrystalline state of fenofibrate in ALC formulation. The ALC formulation achieved almost complete dissolution within 30 minutes, whereas the untreated powder and physical mixture exhibited less than 15% drug release. Furthermore, ALC formulation effectively increased the peak plasma concentration (C max) and area under the curve (AUC) of fenofibric acid (an active metabolite) in rats by approximately 13- and seven-fold, respectively. Furthermore, ALC formulation exhibited much lower moisture sorption behavior than the lyophilized formulation using sucrose as a cryoprotectant. Taken together, the present findings suggest that ALC formulation is promising for improving the oral absorption of poorly soluble fenofibrate. PMID:27042061

  12. Aminoclay–lipid hybrid composite as a novel drug carrier of fenofibrate for the enhancement of drug release and oral absorption

    PubMed Central

    Yang, Liang; Shao, Yating; Han, Hyo-Kyung

    2016-01-01

    This study aimed to prepare the aminoclay–lipid hybrid composite to enhance the drug release and improve the oral bioavailability of poorly water-soluble fenofibrate. Antisolvent precipitation coupled with an immediate freeze-drying method was adopted to incorporate fenofibrate into aminoclay–lipid hybrid composite (ALC). The optimal composition of the ALC formulation was determined as the ratios of aminoclay to krill oil of 3:1 (w/w), krill oil to fenofibrate of 2:1 (w/w), and antisolvent to solvent of 6:4 (v/v). The morphological characteristics of ALC formulation were determined using scanning electron microscopy, differential scanning calorimetry, and X-ray powder diffraction, which indicated microcrystalline state of fenofibrate in ALC formulation. The ALC formulation achieved almost complete dissolution within 30 minutes, whereas the untreated powder and physical mixture exhibited less than 15% drug release. Furthermore, ALC formulation effectively increased the peak plasma concentration (Cmax) and area under the curve (AUC) of fenofibric acid (an active metabolite) in rats by approximately 13- and seven-fold, respectively. Furthermore, ALC formulation exhibited much lower moisture sorption behavior than the lyophilized formulation using sucrose as a cryoprotectant. Taken together, the present findings suggest that ALC formulation is promising for improving the oral absorption of poorly soluble fenofibrate. PMID:27042061

  13. Cholesterol absorption.

    PubMed

    Ostlund, Richard E

    2002-03-01

    Cholesterol absorption is a key regulatory point in human lipid metabolism because it determines the amount of endogenous biliary as well as dietary cholesterol that is retained, thereby influencing whole body cholesterol balance. Plant sterols (phytosterols) and the drug ezetimibe reduce cholesterol absorption and low-density lipoprotein cholesterol in clinical trials, complementing the statin drugs, which inhibit cholesterol biosynthesis. The mechanism of cholesterol absorption is not completely known but involves the genes ABC1, ABCG5, and ABCG8, which are members of the ATP-binding cassette protein family and appear to remove unwanted cholesterol and phytosterols from the enterocyte. ABC1 is upregulated by the liver X (LXR) and retinoid X (RXR) nuclear receptors. Acylcholesterol acytransferase-2 is an intestinal enzyme that esterifies absorbed cholesterol and increases cholesterol absorption when dietary intake is high. New clinical treatments based on better understanding of absorption physiology are likely to substantially improve clinical cholesterol management in the future. PMID:17033296

  14. The absorptive flux of the anti-epileptic drug substance vigabatrin is carrier-mediated across Caco-2 cell monolayers.

    PubMed

    Nøhr, Martha Kampp; Hansen, Steen Honoré; Brodin, Birger; Holm, René; Nielsen, Carsten Uhd

    2014-01-23

    Vigabatrin is an anti-epileptic drug substance. The oral bioavailability of vigabatrin is high (60-70%), however, little is known about the mechanism(s) mediating the intestinal absorption. The aim of the present study was to identify which solute carrier(s) are involved in the absorption of vigabatrin in Caco-2 cells, a cell culture model of the small intestinal epithelium. The uptake and transepithelial flux of vigabatrin was measured using an LC-MS method for quantification. Transepithelial transport of vigabatrin was shown to be proton-dependent and polarized in the apical-to-basolateral (A-B) direction. The A-B flux of vigabatrin had a saturable component and a passive component, indicating the presence of a carrier system in parallel with a passive permeability. The Michaelis constant, Km, of the transepithelial A-B flux of vigabatrin was estimated to be 32.8±7.4 mM (n=3-5), whereas the Km of the apical uptake was found to be 12.7±3.7 mM (n=3). The carrier-mediated transepithelial A-B flux of vigabatrin accounted for 80-95% (50.0-1.0mM) of the total A-B flux. The transepithelial A-B flux (as well as apical uptake) of vigabatrin was significantly decreased upon addition of substrates or inhibitors of the human proton-coupled amino acid transporter (hPAT1) to the apical solution. The present study indicates that the transepithelial A-B flux of vigabatrin is mainly mediated by hPAT1 in Caco-2 cells at dose-relevant concentrations. PMID:24008184

  15. Preformulation characterization and in vivo absorption in beagle dogs of JFD, a novel anti-obesity drug for oral delivery.

    PubMed

    Fan, Yunzhou; Yang, Meiyan; Wang, Yuli; Li, Yanyou; Zhou, Yuanda; Chen, Xiaoping; Shan, Li; Wei, Jun; Gao, Chunsheng

    2015-05-01

    JFD (N-isoleucyl-4-methyl-1,1-cyclopropyl-1-(4-chlorine)phenyl-2-amylamine·HCl) is a novel investigational anti-obesity drug without obvious cardiotoxicity. The objective of this study was to characterize the key physicochemical properties of JFD, including solution-state characterization (ionization constant, partition coefficient, aqueous and pH-solubility profile), solid-state characterization (particle size, thermal analysis, crystallinity and hygroscopicity) and drug-excipient chemical compatibility. A supporting in vivo absorption study was also carried out in beagle dogs. JFD bulk powders are prismatic crystals with a low degree of crystallinity, particle sizes of which are within 2-10 μm. JFD is highly hygroscopic, easily deliquesces to an amorphous glass solid and changes subsequently to another crystal form under an elevated moisture/temperature condition. Similar physical instability was also observed in real-time CheqSol solubility assay. pK(a) (7.49 ± 0.01), log P (5.10 ± 0.02) and intrinsic solubility (S0) (1.75 μg/ml) at 37 °C of JFD were obtained using potentiometric titration method. Based on these solution-state properties, JFD was estimated to be classified as BCS II, thus its dissolution rate may be an absorption-limiting step. Moreover, JFD was more chemically compatible with dibasic calcium phosphate, mannitol, hypromellose and colloidal silicon dioxide than with lactose and magnesium stearate. Further, JFD exhibited an acceptable pharmacokinetic profiling in beagle dogs and the pharmacokinetic parameters T(max), C(max), AUC(0-t) and absolute bioavailability were 1.60 ± 0.81 h, 0.78 ± 0.47 μg/ml, 3.77 ± 1.85 μg·h/ml and 52.30 ± 19.39%, respectively. The preformulation characterization provides valuable information for further development of oral administration of JFD. PMID:24694186

  16. In vitro drug release and ex vivo percutaneous absorption of resveratrol cream using HPLC with zirconized silica stationary phase.

    PubMed

    Polonini, Hudson Caetano; Bastos, Carina de Almeida; de Oliveira, Marcone Augusto Leal; da Silva, Carla Grazieli Azevedo; Collins, Carol Hollingworth; Brandão, Marcos Antônio Fernandes; Raposo, Nádia Rezende Barbosa

    2014-02-01

    Since the designs of optimal formulations for resveratrol permeation via the skin are lacking, the aim of this study was to establish the profile of resveratrol permeability into and across human skin. For that, a laboratory-made chromatographic column was used (Zr-PMODS), with its performance being compared to a traditional C18 column. In vitro drug release was conducted with polysulfone membranes, and the flux (JS) was 30.49 μg cm(-2) h(-1)), with a lag time (LT) of 0.04 h, following a pseudo-first-order kinetics. For ex vivo percutaneous absorption using excised female human skin, the kinetic profile was the same, but JS was 0.87 μg cm(-2) h(-1) and LT was 0.97 h. From the initials 49.30 μg applied to the skin, 9.50 μg were quantified in the receptor medium, 20.48 μg was retained at the stratum corneum (do not account as permeated) and 21.41 μg was retained at the viable epidermis+dermis (account as permeated), totalizing 30.90 μg of resveratrol permeated after 24 h of application (62.6%). From these results, one can conclude that a person using the 1-g emulsion dose released by the pump containing 20mg of resveratrol will have, theoretically, 12.53 mg of it liberated into his bloodstream, gradually and continuously for 24 h. PMID:24381018

  17. Prediction of oral absorption of griseofulvin, a BCS class II drug, based on GITA model: utilization of a more suitable medium for in-vitro dissolution study.

    PubMed

    Fujioka, Yoshitsugu; Kadono, Keitaro; Fujie, Yasuko; Metsugi, Yukiko; Ogawara, Ken-ichi; Higaki, Kazutaka; Kimura, Toshikiro

    2007-06-01

    The in-vivo absorbability of drugs categorized into the biopharmaceutics classification system (BCS) class II is very difficult to be predicted because of the large variability in the absorption and/or dissolution kinetics and the lack of an adequate in-vitro system for evaluating the dissolution behavior. We tried to predict the in-vivo absorption kinetics of griseofulvin, categorized into BCS class II, orally administrated as powders into rats, based on Gastrointestinal-Transit-Absorption model (GITA model), consisting of the absorption, dissolution and GI-transit processes. Using the dissolution rate constants (k(dis)) of griseofulvin obtained with JP 1st solution, JP 2nd solution, FaSSIF, FeSSIF and modified SIBLM as a medium, simulation lines were not able to describe the observed mean plasma profile at all. On the other hand, a calculated line provided by employing k(dis) obtained with MREVID 2 (medium reflecting in-vivo dissolution 2), a new medium, was in better agreement with the observed mean plasma profile than existing media, indicating that the utilization of adequate k(dis) value made it possible to predict the in-vivo absorption kinetics of drugs classified into BCS class II based on GITA model and that MREVID 2 could be a useful medium for describing the in-vivo dissolution kinetics. PMID:17442444

  18. Immunological control of drug absorption from the gastrointestinal tract: the mechanism whereby intestinal anaphylaxis interferes with the intestinal absorption of bromthymol blue in the rat.

    PubMed

    Yamamoto, A; Utsumi, E; Sakane, T; Hamaura, T; Nakamura, J; Hashida, M; Sezaki, H

    1986-05-01

    Rats were immunized intraperitoneally with ovalbumin and the disappearance of bromthymol blue (BTB) from the intestinal lumen, its accumulation in the tissue, and its net absorption were examined by means of an in-situ recirculation technique during local anaphylaxis. The disappearance of BTB from the intestinal lumen and its net absorption were significantly reduced, but there was no significant effect on its accumulation in the tissue. The pH value of the luminal solution and the perfusate volume were not influenced by intraluminal challenge with the antigen in ovalbumin-immunized rats. In addition, no significant effect was observed on intestinal permeability to BTB in the in-vitro everted sac technique. The intestinal blood flow, measured by a hydrogen clearance method, was not reduced significantly by the intraluminal exposure to antigen. There was enhanced Evans Blue leakage and mucus release in the perfusate after intraluminal challenge with ovalbumin in ovalbumin-immunized rats, but not in non-immunized rats. A significant increase of BTB binding with macromolecular substances in the perfusate was observed during the local anaphylaxis. These findings suggest that the decreased absorption of BTB is due to the interaction with the macromolecular substances in the perfusate during local anaphylaxis. PMID:2872311

  19. Analysis of illicit drugs in human urine by micellar electrokinetic capillary chromatography with on-column fast scanning polychrome absorption detection.

    PubMed

    Wernly, P; Thormann, W

    1991-12-15

    Using micellar electrokinetic capillary chromatography (MECC) with a borate/phosphate buffer containing 75 mM SDS (pH 9.1), common drugs of abuse and/or their metabolites, including opioids, benzoylecgonine, amphetamines, and methaqualone, can easily be analyzed. After solid-phase extraction of 5 mL of urine, drug concentrations down to about 100 ng/mL can be unambiguously monitored with on-column multiwavelength detection. Peak assignment is achieved through comparison of retention times and absorption spectra of eluting peaks with those of computer-stored model runs. The effectiveness of the approach is demonstrated with data obtained from different patient urines which tested positively for one or several drugs using nonisotopic immunoassays. Results suggest that MECC of illicit drugs is a highly specific and sensitive instrumental approach suitable for confirmation testing following a positive response of a toxicological screening procedure. PMID:1789451

  20. The effect of E. coli STa enterotoxin on the absorption of weakly dissociable anti-malarial drugs from rat intestine in vivo.

    PubMed Central

    Rawlings, J. M.; Lynch, J.; Lucas, M. L.

    1991-01-01

    1. The effect of E. coli heat stable (STa) enterotoxin on the absorption of radiolabelled anti-malarial weak bases and their appearance in peripheral blood was assessed in vivo by a recirculation procedure in rat intestinal loops. 2. Enterotoxin increased the jejunal disappearance of quinine (P less than 0.05), trimethoprim (P less than 0.05), proguanil (P less than 0.05) and chloroquine (P less than 0.001) and left pyrimethamine disappearance unaltered. Peripheral blood levels of trimethoprim (P less than 0.02) and proguanil (P less than 0.05) were higher after STa exposure. 3. In the ileum, enterotoxin increased the luminal disappearance (P less than 0.05) and peripheral blood appearance (P less than 0.001) of chloroquine. The luminal disappearance rate of trimethoprim was reduced (P less than 0.05) and that of pyrimethamine unchanged. 4. The increased jejunal absorption of the anti-malarial drugs occurred despite STa causing a reduction in the amount of net fluid absorption. It seems likely that the enhanced absorption with STa exposure is related to the effect of STa on the microclimate pH. An elevation in the microclimate pH would increase the amount of undissociated weak base available for non-ionic diffusion. 5. The favourable elevation of microclimate pH by STa seemed to be outweighted by the reduced fluid absorption in the ileum. Only chloroquine still showed enhanced absorption in the ileum and this may have been because unlike the other antimalarial drugs, chloroquine has two dissociable groups likely to be affected by the mucosal surface pH changes. PMID:1878755

  1. Enhanced absorption of hydroxysafflor yellow A using a self-double-emulsifying drug delivery system: in vitro and in vivo studies.

    PubMed

    Lv, Liang-Zhong; Tong, Chen-Qi; Lv, Qing; Tang, Xin-Jiang; Li, Li-Ming; Fang, Qing-Xia; Yu, Jia; Han, Min; Gao, Jian-Qing

    2012-01-01

    Hydroxysafflor yellow A (HSYA), the main active ingredient of the safflower plant (Carthamus tinctorius L.), is a hydrophilic drug with low oral bioavailability. Water-in-oil-in-water (w/o/w) double emulsions may enhance the oral absorption of HSYA. In this study, we prepared a self-double-emulsifying drug delivery system (SDEDDS) to improve the absorption of HSYA. SDEDDS consists of water in oil emulsions and hydrophilic surfactants that can self-emulsify into w/o/w double emulsions in the aqueous gastrointestinal environment. Confocal laser scanning micrographs showed that spherical droplets were uniformly distributed in the dispersion medium with narrow particle size distribution and could form fine w/o/w double emulsions upon dilution in dispersion medium with gentle stirring. The dispersed oil droplets contained small dispersed aqueous droplets consistent with the characteristics of double emulsions. Furthermore, in vitro cellular experiments were performed to study the mechanism of the absorption promoting effect of SDEDDS. The accumulation of rhodamine-123 in Caco-2 cells was used to evaluate the efflux transport of p-glycoprotein inhibitor. Histopathologic studies on the rat intestine showed that SDEDDS can cause mucosal damage to a certain degree of toxicity, however this was not serious. These results suggest that SDEDDS can greatly improve the oral absorption of HSYA. Given the toxicity demonstrated to the small intestine, the formulation prescription should be improved to enhance security in the future. PMID:22888246

  2. A redox-flow electrochromic window.

    PubMed

    Jennings, James R; Lim, Wei Yang; Zakeeruddin, Shaik M; Grätzel, Michael; Wang, Qing

    2015-02-01

    A low-cost electrochromic (EC) window based on a redox-flow system that does not require expensive transparent conductive oxide (TCO) substrates is introduced and demonstrated for the first time. An aqueous I3–/I– redox electrolyte is used in place of a TCO to oxidize/reduce a molecular layer of an EC triphenylamine derivative that is anchored to a mesoporous TiO2 scaffold on the inner faces of a double-paned window. The redox electrolyte is electrochemically oxidized/reduced in an external two-compartment cell and circulated through the window cavity using an inexpensive peristaltic pump, resulting in coloration or decoloration of the window due to reaction of the redox solution with the triphenylamine derivative. The absorption characteristics, coloration/decoloration times, and cycling stability of the prototype EC window are evaluated, and prospects for further development are discussed. PMID:25584903

  3. Expression Profile of Drug and Nutrient Absorption Related Genes in Madin-Darby Canine Kidney (MDCK) Cells Grown under Differentiation Conditions

    PubMed Central

    Quan, Yong; Jin, Yisheng; Faria, Teresa N.; Tilford, Charles A.; He, Aiqing; Wall, Doris A.; Smith, Ronald L.; Vig, Balvinder S.

    2012-01-01

    The expression levels of genes involved in drug and nutrient absorption were evaluated in the Madin-Darby Canine Kidney (MDCK) in vitro drug absorption model. MDCK cells were grown on plastic surfaces (for 3 days) or on Transwell® membranes (for 3, 5, 7, and 9 days). The expression profile of genes including ABC transporters, SLC transporters, and cytochrome P450 (CYP) enzymes was determined using the Affymetrix® Canine GeneChip®. Expression of genes whose probe sets passed a stringent confirmation process was examined. Expression of a few transporter (MDR1, PEPT1 and PEPT2) genes in MDCK cells was confirmed by RT-PCR. The overall gene expression profile was strongly influenced by the type of support the cells were grown on. After 3 days of growth, expression of 28% of the genes was statistically different (1.5-fold cutoff, p < 0.05) between the cells grown on plastic and Transwell® membranes. When cells were differentiated on Transwell® membranes, large changes in gene expression profile were observed during the early stages, which then stabilized after 5–7 days. Only a small number of genes encoding drug absorption related SLC, ABC, and CYP were detected in MDCK cells, and most of them exhibited low hybridization signals. Results from this study provide valuable reference information on endogenous gene expression in MDCK cells that could assist in design of drug-transporter and/or drug-enzyme interaction studies, and help interpret the contributions of various transporters and metabolic enzymes in studies with MDCK cells. PMID:24300234

  4. In vitro--in silico--in vivo drug absorption model development based on mechanistic gastrointestinal simulation and artificial neural networks: nifedipine osmotic release tablets case study.

    PubMed

    Ilić, Marija; Ðuriš, Jelena; Kovačević, Ivan; Ibrić, Svetlana; Parojčić, Jelena

    2014-10-01

    In vitro--in vivo correlations (IVIVC) are generally accepted as a valuable tool in modified release formulation development aimed at (i) quantifying the in vivo drug delivery profile and formulation related effects on absorption; (ii) establishing clinically relevant dissolution specifications and (iii) supporting the biowaiver claims. The aim of the present study was to develop relevant IVIVC models based on mechanistic gastrointestinal simulation (GIS) and artificial neural network (ANN) analysis and to evaluate their applicability and usefulness in biopharmaceutical drug characterisation. Nifedipine osmotic release tablets were selected as model drug product on the basis of their robustness, dissolution limited drug absorption and the availability of relevant literature data. Although the osmotic release tablets have been designed to be robust against the influence of physiological conditions in the gastrointestinal tract, notable differences in nifedipine dissolution kinetics were observed depending on the in vitro experimental conditions employed. The results obtained indicate that both GIS and ANN model developed were sensitive to input kinetics represented by the in vitro profiles obtained under various experimental conditions. Different in silico approaches may be successfully employed in the in vitro--in silico--in vivo model development. However, the results obtained may differ and relevant outcomes are sensitive to the methodology employed. PMID:24911992

  5. Studies on effective atomic numbers for photon energy absorption and electron density of some narcotic drugs in the energy range 1 keV-20 MeV

    NASA Astrophysics Data System (ADS)

    Gounhalli, Shivraj G.; Shantappa, Anil; Hanagodimath, S. M.

    2013-04-01

    Effective atomic numbers for photon energy absorption ZPEA,eff, photon interaction ZPI,eff and for electron density Nel, have been calculated by a direct method in the photon-energy region from 1 keV to 20 MeV for narcotic drugs, such as Heroin (H), Cocaine (CO), Caffeine (CA), Tetrahydrocannabinol (THC), Cannabinol (CBD), Tetrahydrocannabivarin (THCV). The ZPEA,eff, ZPI,eff and Nel values have been found to change with energy and composition of the narcotic drugs. The energy dependence ZPEA,eff, ZPI,eff and Nel is shown graphically. The maximum difference between the values of ZPEA,eff, and ZPI,eff occurs at 30 keV and the significant difference of 2 to 33% for the energy region 5-100 keV for all drugs. The reason for these differences is discussed.

  6. A Quantitative Review and Meta-models of the Variability and Factors Affecting Oral Drug Absorption-Part II: Gastrointestinal Transit Time.

    PubMed

    Abuhelwa, Ahmad Y; Foster, David J R; Upton, Richard N

    2016-09-01

    This study aimed to conduct a quantitative meta-analysis for the values of, and variability in, gastrointestinal (GI) transit times of non-disintegrating single-unit ("tablet") and multiple-unit ("pellets/multi-unit tablet") solid dosage forms, characterize the effect of food on the values and variability in these parameters and present quantitative meta-models of the distributions of GI transit times in the respective GI regions to help inform models of oral drug absorption. The literature was systemically reviewed for the values of, and the variability in, gastric, small intestinal and colonic transit times under fed and fasted conditions. Meta-analysis used the "metafor" package of the R language. Meta-models of GI transit were assumed to be log-normally distributed between the studied populations. Twenty-nine studies including 125 reported means and standard deviations were used in the meta-analysis. Caloric content of administered food increased variability and delayed the gastric transit of both pellets and tablets. Conversely, food caloric content reduced the variability but had no significant influence on the mean small intestinal transit time (SITT). Food had no significant effect on the transit time through the colon. The transit of pellets through the colon was significantly slower than that of single-unit tablets which is most likely related to their smaller size. GI transit times may influence the dissolution and absorption of oral drugs. The meta-models of GI transit times may be used as part of semi-physiological absorption models to characterize the influence of transit time on the dissolution, absorption and in vivo pharmacokinetic profiles of oral drugs. PMID:27439620

  7. A highly sensitive method for in vitro testing of fluorinated drug candidates using high-resolution continuum source molecular absorption spectrometry (HR-CS MAS).

    PubMed

    Würtenberger, Irene; Gust, Ronald

    2014-05-01

    We report here the development, optimization, and evaluation of a highly sensitive method for the determination of fluorine in biological matrices employing highresolution continuum source molecular absorption spectrometry (HR-CS MAS), suitable for pharmacological testing of fluorine-containing drug candidates. For this purpose, the most important parameters were studied in detail and subsequently optimized using a multivariate approach based on experimental design methodology. We developed a new approach employing a graphite tube lined with tantalum foil, thereby significantly enhancing sensitivity, while interferences from phosphorus monoxide (PO) molecular absorption due to the complex phosphate-rich matrix were completely eliminated. The limit of detection and the characteristic mass were 5.79 and 6.08 pg F, respectively. In order to evaluate the accuracy of the procedure, a recovery test was performed using spiked samples from three bioassays (i.e., DNA binding, protein binding, and cellular uptake) and the recovery rates ranged from 97.4 to 106.4%. The proposed method is applicable for preclinical in vitro testing of fluorinated drug molecules and thereby establishes HR-CS atomic absorption spectrometry instrumentation as a universal tool in medicinal chemistry. PMID:24760395

  8. Two-dimensional transport analysis of transdermal drug absorption with a non-perfect sink boundary condition at the skin-capillary interface.

    PubMed

    Simon, Laurent; Ospina, Juan

    2013-07-01

    A transient percutaneous drug absorption model was solved in two dimensions. Clearance of the topically-applied pharmaceutical occured at the skin-capillary boundary. Timolol penetration profiles in the dermal tissue were produced revealing concentration gradients in the directions normal and parallel to the skin surface. Ninety-eight percent of the steady-state flux was reached after 85 h or four time constants. The analytical solution procedure agreed with published results. As the clearance rate increased relative to diffusion, the delivery rate and amount of drug absorbed into the bloodstream increased while the time to reach the equilibrium flux decreased. Researchers can apply the closed-form expressions to simulate the process, estimate key parameters and design devices that meet specific performance requirements. PMID:23624255

  9. Human small intestinal and colonic tissue mounted in the Ussing chamber as a tool for characterizing the intestinal absorption of drugs.

    PubMed

    Rozehnal, Veronika; Nakai, Daisuke; Hoepner, Ursula; Fischer, Thomas; Kamiyama, Emi; Takahashi, Masayuki; Yasuda, Satoru; Mueller, Juergen

    2012-08-15

    The purpose of this study was to validate human small intestinal and colonic tissue mounted in the Ussing chamber as a tool for predicting the oral drug absorption in humans with the main focus on moderately and poorly permeable compounds. The obtained apparent permeability coefficient (P(app)) of eleven test compounds was compared to their fraction absorbed (Fa) in humans taken from the literature. Beside the conventional P(app) a new parameter, the apparent permeability coefficient total (P(app,total)), involving both the apical-to-basolateral permeability and the time-dependent compound accumulation in the tissue was established. The permeability of lucifer yellow (LY), a fluorescent marker of the paracellular pathway and the test compounds showed no obvious differences between small intestine and colon. Furthermore, small intestinal and colonic tissue from a single donor showed similar permeability of both LY and a transcellularly transported compound metoprolol. All test compounds including low molecular weight hydrophilic compounds such as metformin, atenolol, sulpiride and famotidine showed adequate permeability reflecting human Fa values (R(2)=0.87). The P(app) values of digoxin, a P-glycoprotein (P-gp) substrate, were not significantly affected by the addition of verapamil, a P-gp inhibitor. In contrast, the P(app,total) values of digoxin increased approximately threefold in the presence of verapamil. In conclusion, both small intestinal and colonic tissue mounted in the Ussing chamber provide a good opportunity to predict the oral drug absorption rate in humans even for moderately and poorly absorbed compounds. The novel calculation of P(app,total) allows the study of the carrier-mediated drug-drug interactions in human intestine. PMID:22418036

  10. Overview on gastroretentive drug delivery systems for improving drug bioavailability.

    PubMed

    Lopes, Carla M; Bettencourt, Catarina; Rossi, Alessandra; Buttini, Francesca; Barata, Pedro

    2016-08-20

    In recent decades, many efforts have been made in order to improve drug bioavailability after oral administration. Gastroretentive drug delivery systems are a good example; they emerged to enhance the bioavailability and effectiveness of drugs with a narrow absorption window in the upper gastrointestinal tract and/or to promote local activity in the stomach and duodenum. Several strategies are used to increase the gastric residence time, namely bioadhesive or mucoadhesive systems, expandable systems, high-density systems, floating systems, superporous hydrogels and magnetic systems. The present review highlights some of the drugs that can benefit from gastroretentive strategies, such as the factors that influence gastric retention time and the mechanism of action of gastroretentive systems, as well as their classification into single and multiple unit systems. PMID:27173823

  11. A new Pharmaceutical Aerosol Deposition Device on Cell Cultures (PADDOCC) to evaluate pulmonary drug absorption for metered dose dry powder formulations.

    PubMed

    Hein, Stephanie; Bur, Michael; Schaefer, Ulrich F; Lehr, Claus-Michael

    2011-01-01

    Absorption studies with aerosol formulation delivered by metered dose inhalers across cell- and tissue-based in vitro models of the pulmonary epithelia are not trivial due to the complexity of the processes involved: (i) aerosol generation and deposition, (ii) drug release from the carrier, and (iii) absorption across the epithelial air-blood barrier. In contrast to the intestinal mucosa, pulmonary epithelia are only covered by a thin film of lining fluid. Submersed cell culture systems would not allow to studying the deposition of aerosol particles and their effects on this delicate epithelial tissue. We developed a new Pharmaceutical Aerosol Deposition Device on Cell Cultures (PADDOCC) to mimic the inhalation of a single metered aerosol dose and its subsequent deposition on filter-grown pulmonary epithelial cell monolayers exposed to an air-liquid interface. The reproducibility of deposition of these dry powder aerosols and subsequent drug transport across Calu-3 monolayers with commercially available dry powder inhalers containing salbutamol sulphate or budesonide could be demonstrated. In the context of developing new dry powder aerosol formulations, PADDOCC appears as a useful tool, allowing reducing animal testing and faster translation into clinical trials. PMID:20951200

  12. Effect of Gastric Fluid Volume on the In Vitro Dissolution and In Vivo Absorption of BCS Class II Drugs: a Case Study with Nifedipine.

    PubMed

    Nader, Ahmed M; Quinney, Sara K; Fadda, Hala M; Foster, David R

    2016-07-01

    Nifedipine is a BCS Class II drug used for treatment of hypertension and preterm labor. Large inter-patient variability in nifedipine absorption results in variable exposure among different patients. We conducted in vitro dissolution studies to compare nifedipine dissolution from immediate release (IR) capsules with different volumes of dissolution media. Results from dissolution studies were used to design a crossover study in healthy volunteers to evaluate the effect of coadministered water volume with nifedipine 10 mg IR capsules on nifedipine pharmacokinetics, especially absorption (C max, t max, and AUC0-6). Dissolution studies demonstrated that larger gastric fluid volumes result in enhanced nifedipine dissolution from 10 mg IR cosolvent capsules (73 vs. 17% in 200 and 100 mL simulated gastric fluid, respectively, at 30 min). The pharmacokinetic crossover study in healthy volunteers (N = 6) did not show a significant effect of the water volume administered with the capsule (50 vs. 250 mL) on C max, t max, or AUC0-6 of orally administered nifedipine IR capsules (10 mg). However, administration of large water volumes resulted in lower variability in nifedipine C max (47 vs. 70% for 250 and 50 mL, respectively). Administration of large water volumes with nifedipine 10 mg IR cosolvent capsules may reduce inter-individual variability in plasma exposure. Evaluation of similar effects in other BCS Class II drugs is recommended. PMID:27106837

  13. The effect of macrophage and angiogenesis inhibition on the drug release and absorption from an intramuscular sustained-release paliperidone palmitate suspension.

    PubMed

    Darville, Nicolas; van Heerden, Marjolein; Mariën, Dirk; De Meulder, Marc; Rossenu, Stefaan; Vermeulen, An; Vynckier, An; De Jonghe, Sandra; Sterkens, Patrick; Annaert, Pieter; Van den Mooter, Guy

    2016-05-28

    The intramuscular (IM) administration of long-acting injectable (LAI) aqueous nano-/microsuspensions elicits a chronic granulomatous injection site reaction, which recently has been hypothesized to drive the (pro)drug dissolution and systemic absorption resulting in flip-flop pharmacokinetics. The goal of this mechanistic study was to investigate the effects of the local macrophage infiltration and angiogenesis on the systemic drug exposure following a single IM administration of a paliperidone palmitate (PP) LAI nano-/microsuspension in the rat. Liposomal clodronate (CLO) and sunitinib (SNT) were co-administered to inhibit the depot infiltration and nano-/microparticle phagocytosis by macrophages, and the neovascularization of the depot, respectively. Semi-quantitative histopathology of the IM administration sites at day 1, 3, 7, 14, 21 and 28 after dosing with PP-LAI illustrated that CLO significantly decreased the rate and extent of the granulomatous inflammatory reaction. The macrophage infiltration was slowed down, but only partially suppressed by CLO and this translated in paliperidone (PAL) plasma concentration-time profiles that resembled those observed upon injection of PP-LAI only, albeit with a lower PAL input rate and delayed maximum plasma concentration (CMAX). Conversely, SNT treatment completely suppressed the granulomatous reaction, besides effectively inhibiting the neovascularization of the PP-LAI depot. This resulted in an even slower systemic PAL input with delayed and lower maximum PAL CMAX. The reduced PP-LAI lymph node retention after CLO and SNT treatment, as well as pharmacokinetic drug-drug interactions were rejected as possible sources of the observed pharmacokinetic differences. The biphasic PAL plasma concentration-time profiles could best be described by an open first-order disposition model with parallel fast (first-order) and slow (sequential zero-first-order) absorption. The correlation of the pharmacokinetic data with the

  14. Targeting SVCT for enhanced drug absorption: Synthesis and in vitro evaluation of a novel vitamin C conjugated prodrug of saquinavir

    PubMed Central

    Luo, Shuanghui; Wang, Zhiying; Patel, Mitesh; Khurana, Varun; Zhu, Xiaodong; Pal, Dhananjay; Mitra, Ashim. K.

    2015-01-01

    In order to improve oral absorption, a novel prodrug of saquinavir (Saq), ascorbyl-succinic-saquinavir (AA-Su-Saq) targeting sodium dependent vitamin C transporter (SVCT) was synthesized and evaluated. Aqueous solubility, stability and cytotoxicity were determined. Affinity of AA-Su-Saq towards effluxpump P-glycoprotein (P-gp) and recognition of AA-Su-Saq by SVCT were studied. Transepithelial permeability across polarized MDCK-MDR1 and Caco-2 cells were determined. Metabolic stability of AA-Su-Saq in rat liver microsomes was investigated. AA-Su-Saq appears to be fairly stable in both DPBS and Caco-2 cells with half lives of 9.65 and 5.73 h, respectively. Uptake of [3H]Saquinavir accelerated by 2.7 and 1.9 fold in the presence of 50 μM Saq and AA-Su-Saq in MDCK-MDR1 cells. Cellular accumulation of [14C]AA diminished by about 50–70% relative to control in the presence of 200 μM AA-Su-Saq in MDCK-MDR1 and Caco-2 cells. Uptake of AA-Su-Saq was lowered by 27% and 34% in the presence of 5 mM AA in MDCK-MDR1 and Caco-2 cells, respectively. Absorptive permeability of AA-Su-Saq was elevated about 4-5 fold and efflux index reduced by about 13-15 fold across the polarized MDCK-MDR1 and Caco-2 cells. Absorptive permeability of AA-Su-Saq decreased 44% in the presence of 5 mM AA across MDCK-MDR1 cells. AA-Su-Saq was devoid of cytotoxicity over the concentration range studied. AA-Su-Saq significantly enhanced the metabolic stability but lowered the affinity towards CYP3A4. In conclusion, prodrug modification of Saq through conjugation to AA via a linker significantly raised the absorptive permeability and metabolic stability. Such modification also caused significant evading of P-gp mediated efflux and CYP3A4 mediated metabolism. SVCT targeted prodrug approach can be an attractive strategy to enhance the oral absorption and systemic bioavailability of anti-HIV protease inhibitors. PMID:21571053

  15. Efficient Windows Collaborative

    SciTech Connect

    Nils Petermann

    2010-02-28

    The project goals covered both the residential and commercial windows markets and involved a range of audiences such as window manufacturers, builders, homeowners, design professionals, utilities, and public agencies. Essential goals included: (1) Creation of 'Master Toolkits' of information that integrate diverse tools, rating systems, and incentive programs, customized for key audiences such as window manufacturers, design professionals, and utility programs. (2) Delivery of education and outreach programs to multiple audiences through conference presentations, publication of articles for builders and other industry professionals, and targeted dissemination of efficient window curricula to professionals and students. (3) Design and implementation of mechanisms to encourage and track sales of more efficient products through the existing Window Products Database as an incentive for manufacturers to improve products and participate in programs such as NFRC and ENERGY STAR. (4) Development of utility incentive programs to promote more efficient residential and commercial windows. Partnership with regional and local entities on the development of programs and customized information to move the market toward the highest performing products. An overarching project goal was to ensure that different audiences adopt and use the developed information, design and promotion tools and thus increase the market penetration of energy efficient fenestration products. In particular, a crucial success criterion was to move gas and electric utilities to increase the promotion of energy efficient windows through demand side management programs as an important step toward increasing the market share of energy efficient windows.

  16. Air transparent soundproof window

    SciTech Connect

    Kim, Sang-Hoon; Lee, Seong-Hyun

    2014-11-15

    A soundproof window or wall which is transparent to airflow is presented. The design is based on two wave theories: the theory of diffraction and the theory of acoustic metamaterials. It consists of a three-dimensional array of strong diffraction-type resonators with many holes centered on each individual resonator. The negative effective bulk modulus of the resonators produces evanescent wave, and at the same time the air holes with subwavelength diameter existed on the surfaces of the window for macroscopic air ventilation. The acoustic performance levels of two soundproof windows with air holes of 20mm and 50mm diameters were measured. The sound level was reduced by about 30 - 35dB in the frequency range of 400 - 5,000Hz with the 20mm window, and by about 20 - 35dB in the frequency range of 700 - 2,200Hz with the 50mm window. Multi stop-band was created by the multi-layers of the window. The attenuation length or the thickness of the window was limited by background noise. The effectiveness of the soundproof window with airflow was demonstrated by a real installation.

  17. Color Wheel Windows

    ERIC Educational Resources Information Center

    Leonard, Stephanie

    2012-01-01

    In this article, the author describes a painting and drawing lesson which was inspired by the beautiful circular windows found in cathedrals and churches (also known as "rose windows"). This two-week lesson would reinforce both the concept of symmetry and students' understanding of the color wheel. (Contains 1 online resource.)

  18. A Quantitative Review and Meta-Models of the Variability and Factors Affecting Oral Drug Absorption-Part I: Gastrointestinal pH.

    PubMed

    Abuhelwa, Ahmad Y; Foster, David J R; Upton, Richard N

    2016-09-01

    This study aimed to conduct a quantitative meta-analysis for the values of, and variability in, gastrointestinal (GI) pH in the different GI segments; characterize the effect of food on the values and variability in these parameters; and present quantitative meta-models of distributions of GI pH to help inform models of oral drug absorption. The literature was systemically reviewed for the values of, and the variability in, GI pH under fed and fasted conditions. The GI tract was categorized into the following 10 distinct regions: stomach (proximal, mid-distal), duodenum (proximal, mid-distal), jejunum and ileum (proximal, mid, and distal small intestine), and colon (ascending, transverse, and descending colon). Meta-analysis used the "metafor" package of the R language. The time course of postprandial stomach pH was modeled using NONMEM. Food significantly influenced the estimated meta-mean stomach and duodenal pH but had no significant influence on small intestinal and colonic pH. The time course of postprandial pH was described using an exponential model. Increased meal caloric content increased the extent and duration of postprandial gastric pH buffering. The different parts of the small intestine had significantly different pH. Colonic pH was significantly different for descending but not for ascending and transverse colon. Knowledge of GI pH is important for the formulation design of the pH-dependent dosage forms and in understanding the dissolution and absorption of orally administered drugs. The meta-models of GI pH may also be used as part of semi-physiological pharmacokinetic models to characterize the effect of GI pH on the in vivo drug release and pharmacokinetics. PMID:27495120

  19. Multi-functional windows

    NASA Astrophysics Data System (ADS)

    Nag, Nagendra; Goldman, Lee M.; Balasubramanian, Sreeram; Sastri, Suri

    2013-06-01

    The requirements for modern aircraft are driving the need for conformal windows for future sensor systems. However, limitations on optical systems and the physical properties of optically transparent materials currently limit the geometry of existing windows and window assemblies to faceted assemblies of flat windows held in weight bearing frames. Novel material systems will have to be developed which combine different materials (e.g. ductile metals with transparent ceramics) into structures that combine transparency with structural integrity. Surmet's demonstrated ability to produce novel transparent ceramic/metal structures will allow us to produce such structures in the types of conformal shapes required for future aircraft applications. Furthermore, the ability to incorporate transparencies into such structures also holds out the promise of creating multi-functional windows which provide a broad range of capabilities that might include RF antennas and de-icing in addition to transparency. Recent results in this area will be presented.

  20. Windows technology assessment

    SciTech Connect

    Baron, J.J.

    1995-10-01

    This assessment estimates that energy loss through windows is approximately 15 percent of all the energy used for space heating and cooling in residential and commercial buildings in New York State. The rule of thumb for the nation as a whole is about 25 percent. The difference may reflect a traditional assumption of single-pane windows while this assessment analyzed installed window types in the region. Based on the often-quoted assumption, in the United States some 3.5 quadrillion British thermal units (Btu) of primary energy, costing some $20 billion, is annually consumed as a result of energy lost through windows. According to this assessment, in New York State, the energy lost due to heat loss through windows is approximately 80 trillion Btu at an annual cost of approximately $1 billion.

  1. Zero Energy Windows

    SciTech Connect

    Arasteh, Dariush; Selkowitz, Steve; Apte, Josh; LaFrance, Marc

    2006-05-17

    Windows in the U.S. consume 30 percent of building heating and cooling energy, representing an annual impact of 4.1 quadrillion BTU (quads) of primary energy. Windows have an even larger impact on peak energy demand and on occupant comfort. An additional 1 quad of lighting energy could be saved if buildings employed effective daylighting strategies. The ENERGY STAR{reg_sign} program has made standard windows significantly more efficient. However, even if all windows in the stock were replaced with today's efficient products, window energy consumption would still be approximately 2 quads. However, windows can be ''net energy gainers'' or ''zero-energy'' products. Highly insulating products in heating applications can admit more useful solar gain than the conductive energy lost through them. Dynamic glazings can modulate solar gains to minimize cooling energy needs and, in commercial buildings, allow daylighting to offset lighting requirements. The needed solutions vary with building type and climate. Developing this next generation of zero-energy windows will provide products for both existing buildings undergoing window replacements and products which are expected to be contributors to zero-energy buildings. This paper defines the requirements for zero-energy windows. The technical potentials in terms of national energy savings and the research and development (R&D) status of the following technologies are presented: (1) Highly insulating systems with U-factors of 0.1 Btu/hr-ft{sup 2}-F; (2) Dynamic windows: glazings that modulate transmittance (i.e., change from clear to tinted and/or reflective) in response to climate conditions; and (3) Integrated facades for commercial buildings to control/ redirect daylight. Market transformation policies to promote these technologies as they emerge into the marketplace are then described.

  2. Novel Approaches for Visualizing and Analyzing Dose-Timing Data from Electronic Drug Monitors, or "How the 'Broken Window' Theory Pertains to ART Adherence".

    PubMed

    Gill, Christopher J; DeSilva, Mary Bachman; Hamer, Davidson H; Keyi, Xu; Wilson, Ira B; Sabin, Lora

    2015-11-01

    Adherence to antiretroviral medications is usually expressed in terms of the proportion of doses taken. However, the timing of doses taken may also be an important dimension to overall adherence. Little is known about whether patients who mistime doses are also more likely to skip doses. Using data from the completed Adherence for Life randomized controlled trial, we created visual and statistical models to capture and analyze dose timing data collected longitudinally with electronic drug monitors (EDM). From scatter plots depicting dose time versus calendar date, we identified dominant patterns of dose taking and calculated key features [slope of line over calendar date; residual mean standard error (RMSE)]. Each was assessed for its ability to categorize subjects with 'sub-optimal' (<95 % of doses taken) using area under the receiver operating characteristic (AROC) curve analysis. Sixty eight subjects contributed EDM data, with ~300 to 400 observations/subject. While regression line slopes did not predict 'sub-optimal' adherence (AROC 0.51, 95 % CI 0.26-0.75), the variability in dose timing (RMSE) was strongly predictive (AROC 0.79, 95 % CI 0.62-0.97). Compared with the lowest quartile of RMSE (minimal dose time variability), each successive quartile roughly doubled the odds of 'sub-optimal' adherence (OR 2.1, 95 % CI 1.3-3.4). Patterns of dose timing and mistiming are strongly related to overall adherence behavior. Notably, individuals who skip doses are more likely to mistime doses, with the degree of risk positively correlated with the extent of dose timing variability. PMID:25893658

  3. Selecting windows for energy efficiency

    SciTech Connect

    1997-05-01

    New window technologies have increased energy benefits and comfort, and have provided more practical options for consumers. This selection guide will help homeowners, architects, and builders take advantage of the expanding window market. The guide contains three sections: an explanation of energy-related window characteristics, a discussion of window energy performance ratings, and a convenient checklist for window selection.

  4. GA microwave window development

    SciTech Connect

    Moeller, C.P.; Kasugai, A.; Sakamoto, K.; Takahashi, K.

    1994-10-01

    The GA prototype distributed window was tested in a 32 mm diam. waveguide system at a power density suitable for a MW gyrotron, using the JAERI/Toshiba 110 GHz long pulse internal converter gyrotron in the JAERI test stand. The presence of the untilted distributed window had no adverse effect on the gyrotron operation. A pulse length of 10 times the calculated thermal equilibrium time (1/e time) of 30 msec was reached, and the window passed at least 750 pulses greater than 30 msec and 343 pulses greater than 60 msec. Beyond 100 msec, the window calorimetry reached steady state, allowing the window dissipation to be measured in a single pulse. The measured loss of 4.0% agrees both with the estimated loss, on which the stress calculations are based, and with the attenuation measured at low power in the HE{sub 11} mode. After the end of the tests, the window was examined; no evidence of arcing air coating was found in the part of the window directly illuminated by the microwaves, although there was discoloration in a recess containing an optical diagnostic which outgassed, causing a local discharge to occur in that recess. Finally, there was no failure of the metal-sapphire joints during a total operating time of 50 seconds consisting of pulses longer than 30 msec.

  5. The Efficient Windows Collaborative

    SciTech Connect

    Petermann, Nils

    2006-03-31

    The Efficient Windows Collaborative (EWC) is a coalition of manufacturers, component suppliers, government agencies, research institutions, and others who partner to expand the market for energy efficient window products. Funded through a cooperative agreement with the U.S. Department of Energy, the EWC provides education, communication and outreach in order to transform the residential window market to 70% energy efficient products by 2005. Implementation of the EWC is managed by the Alliance to Save Energy, with support from the University of Minnesota and Lawrence Berkeley National Laboratory.

  6. double hung window details, hall window details, entrance door profiles ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    double hung window details, hall window details, entrance door profiles - Chopawamsic Recreational Demonstration Area - Cabin Camp 1, Help's Quarters, Prince William Forest Park, Triangle, Prince William County, VA

  7. Biorelevant media for transport experiments in the Caco-2 model to evaluate drug absorption in the fasted and the fed state and their usefulness.

    PubMed

    Markopoulos, C; Thoenen, F; Preisig, D; Symillides, M; Vertzoni, M; Parrott, N; Reppas, C; Imanidis, G

    2014-04-01

    In this work we developed and characterized transport media that simulate the composition of micellar phase of intestinal fluids in the fasted and, especially, in the fed state and are appropriate for evaluating intestinal drug permeability characteristics using the Caco-2 model (FaSSIF-TM(Caco) and FeSSIF-TM(Caco), respectively). Media composition was based on FaSSIF-V2 and FeSSIF-V2 and recently reported data on total lipid concentrations in the micellar phase of contents of the upper small intestine in the fasted and the fed state and was adapted for cell culture compatibility. Permeation data were evaluated by compartmental kinetic modeling. Permeability coefficients, P, of hydrophilic drugs were not affected by media composition. In contrast, P values of a series of lipophilic compounds measured with FaSSIF-TM(Caco) and FeSSIF-TM(Caco), and reflecting transport by diffusion were smaller than those obtained with a purely aqueous reference transport medium, aq-TM(Caco), following the rank order aq-TM(Caco)>FaSSIF-TM(Caco)>FeSSIF-TM(Caco). The decline of permeability values was stronger as lipophilicity of the compounds increased. Compared with values estimated using aq-TM(Caco), permeability was reduced, depending on the compound, by more than 20- to 100-fold when measured with FeSSIF-TM(Caco) whereas compound ranking in regard to the permeability characteristics was also affected. The impact of reduced P value on flux through the mucosa, hence on drug absorption, in combination with the drug amount loaded on colloidal particles needs to be taken into consideration in PBPK modeling especially when the food effect is evaluated. PMID:24184673

  8. Possible interaction of quinolone antibiotics with peptide transporter 1 in oral absorption of peptide-mimetic drugs.

    PubMed

    Arakawa, Hiroshi; Kamioka, Hiroki; Kanagawa, Masahiko; Hatano, Yasuko; Idota, Yoko; Yano, Kentaro; Morimoto, Kaori; Ogihara, Takuo

    2016-01-01

    The study investigated whether quinolone antibiotics inhibit the PEPT1-mediated uptake of its substrates. Among the quinolones examined, lomefloxacin, moxifloxacin (MFLX) and purlifloxacin significantly inhibited the uptake of PEPT1 substrate phenylalanine-Ψ(CN-S)-alanine (Phe-Ψ-Ala) in HeLa/PEPT1 cells to 31.6 ± 1.3%, 27.6 ± 2.9%, 36.8 ± 2.2% and 32.6 ± 1.4%, respectively. Further examination showed that MFLX was an uncompetitive inhibitor, with an IC50 value of 4.29 ± 1.29 mm. In addition, MFLX significantly decreased the cephalexin and valacyclovir uptake in HeLa/PEPT1 cells. In an in vivo study in rats, the maximum plasma concentration (C(max)) of orally administered Phe-Ψ-Ala was significantly decreased in the presence of MFLX (171 ± 1 ng/ml) compared with that in its absence (244 ± 9 ng/ml). The area under the concentration-time curve (AUC) of orally administered Phe-Ψ-Ala in the presence of MFLX (338 ± 50 ng/ml · h) tended to decrease compared with that in its absence (399 ± 75 ng/ml · h). The oral bioavailability of Phe-Ψ-Ala in the presence and absence of MFLX was 41.7 ± 6.2% and 49.2 ± 9.2%, respectively. The results indicate that administration of quinolone antibiotics concomitantly with PEPT1 substrate drugs may potentially result in drug-drug interaction. PMID:26590007

  9. Cordilleran slab windows

    SciTech Connect

    Thorkelson, D.J.; Taylor, R.P. )

    1989-09-01

    The geometry and geologic implications of subducted spreading ridges are topics that have bedeviled earth scientists ever since the recognition of plate tectonics. As a consequence of subduction of the Kula-Farallon and East Pacific rises, slab windows formed and migrated beneath the North American Cordillera. The probable shape and extent of these windows, which represent the asthenosphere-filled gaps between two separating, subducting oceanic plates, are depicted from the Late Cretaceous to the present. Possible effects of the existence and migration of slab windows on the Cordillera at various times include cessation of arc volcanism and replacement by rift or plate-edge volcanism; lithospheric uplift, attenuation, and extension; and increased intensity of compressional tectonism. Eocene extensional tectonism and alkaline magmatism in southern British Columbia and the northwestern United States were facilitated by slab-window development.

  10. Superconducting radiofrequency window assembly

    DOEpatents

    Phillips, H.L.; Elliott, T.S.

    1997-03-11

    The present invention is a superconducting radiofrequency window assembly for use in an electron beam accelerator. The srf window assembly has a superconducting metal-ceramic design. The srf window assembly comprises a superconducting frame, a ceramic plate having a superconducting metallized area, and a superconducting eyelet for sealing plate into frame. The plate is brazed to eyelet which is then electron beam welded to frame. A method for providing a ceramic object mounted in a metal member to withstand cryogenic temperatures is also provided. The method involves a new metallization process for coating a selected area of a ceramic object with a thin film of a superconducting material. Finally, a method for assembling an electron beam accelerator cavity utilizing the srf window assembly is provided. The procedure is carried out within an ultra clean room to minimize exposure to particulates which adversely affect the performance of the cavity within the electron beam accelerator. 11 figs.

  11. Superconductive radiofrequency window assembly

    DOEpatents

    Phillips, H.L.; Elliott, T.S.

    1998-05-19

    The present invention is a superconducting radiofrequency window assembly for use in an electron beam accelerator. The SRF window assembly has a superconducting metal-ceramic design. The SRF window assembly comprises a superconducting frame, a ceramic plate having a superconducting metallized area, and a superconducting eyelet for sealing plate into frame. The plate is brazed to eyelet which is then electron beam welded to frame. A method for providing a ceramic object mounted in a metal member to withstand cryogenic temperatures is also provided. The method involves a new metallization process for coating a selected area of a ceramic object with a thin film of a superconducting material. Finally, a method for assembling an electron beam accelerator cavity utilizing the SRF window assembly is provided. The procedure is carried out within an ultra clean room to minimize exposure to particulates which adversely affect the performance of the cavity within the electron beam accelerator. 11 figs.

  12. In Situ Perfusion Model in Rat Colon for Drug Absorption Studies: Comparison with Small Intestine and Caco-2 Cell Model.

    PubMed

    Lozoya-Agullo, Isabel; González-Álvarez, Isabel; González-Álvarez, Marta; Merino-Sanjuán, Matilde; Bermejo, Marival

    2015-09-01

    Our aim is to develop and to validate the in situ closed loop perfusion method in rat colon and to compare with small intestine and Caco-2 cell models. Correlations with human oral fraction absorbed (Fa) and human colon fraction absorbed (Fa_colon) were developed to check the applicability of the rat colon model for controlled release (CR) drug screening. Sixteen model drugs were selected and their permeabilities assessed in rat small intestine and colon, and in Caco-2 monolayers. Correlations between colon/intestine/Caco-2 permeabilities versus human Fa and human Fa_colon have been explored to check model predictability and to apply a BCS approach in order to propose a cut off value for CR screening. Rat intestine perfusion with Doluisio's method and single-pass technique provided a similar range of permeabilities demonstrating the possibility of combining data from different laboratories. Rat colon permeability was well correlated with Caco-2 cell-4 days model reflecting a higher paracellular permeability. Rat colon permeabilities were also higher than human colon ones. In spite of the magnitude differences, a good sigmoidal relationship has been shown between rat colon permeabilities and human colon fractions absorbed, indicating that rat colon perfusion can be used for compound classification and screening of CR candidates. PMID:25891783

  13. Energy-efficient windows

    SciTech Connect

    1994-10-01

    This fact sheet describes energy efficient windows for the reduction of home heating and cooling energy consumption. It discusses controlling air leaks by caulking and weatherstripping and by replacing window frames. Reducing heat loss and condensation is discussed by describing the types of glazing materials, the number of glass and air spaces, frame and spacer materials, and the use of movable insulation (shutters, drapes, etc.). A resource list is provided for further information.

  14. The deep oval window.

    PubMed

    Kapur, T R

    1991-09-01

    This article presents the results of an analysis of the variable and surgically important relationship between the oval window, the fossular walls and the related posterior tympanic recesses in 50 temporal bones. The visual impressions of superficial and deep oval windows seem to correspond fairly closely to the depth of the inferior wall of the fossula fenestra vestibuli (FFV). The depth of the superior and anterior walls of the FFV by themselves, did not appear to have such a dominating relationship in determining the deep oval window. There does not appear to be a well defined posterior wall in the vast majority of the specimens (86 per cent). In the event of scar tissue forming between the superior, inferior and anterior walls, the gap between the postero-superior part of the promontory and the posterior tympanic wall (posterior communication) could allow aeration of the region of the deep oval window in such an instance. Closure of this gap by a solid shelf of ponticulus or scar tissue could cause a localized malaeration of the fossula in most cases of deep oval windows. This is an entirely new concept of the likely problems of malaeration of a deep oval window which could arise due to anatomical variations and of the possible safety valve mechanism which could prevent such malaeration and its consequences. PMID:1919338

  15. High Performance Window Retrofit

    SciTech Connect

    Shrestha, Som S; Hun, Diana E; Desjarlais, Andre Omer

    2013-12-01

    The US Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy (EERE) and Traco partnered to develop high-performance windows for commercial building that are cost-effective. The main performance requirement for these windows was that they needed to have an R-value of at least 5 ft2 F h/Btu. This project seeks to quantify the potential energy savings from installing these windows in commercial buildings that are at least 20 years old. To this end, we are conducting evaluations at a two-story test facility that is representative of a commercial building from the 1980s, and are gathering measurements on the performance of its windows before and after double-pane, clear-glazed units are upgraded with R5 windows. Additionally, we will use these data to calibrate EnergyPlus models that we will allow us to extrapolate results to other climates. Findings from this project will provide empirical data on the benefits from high-performance windows, which will help promote their adoption in new and existing commercial buildings. This report describes the experimental setup, and includes some of the field and simulation results.

  16. Effect of Absorption Behavior of Solubilizers on Drug Dissolution in the Gastrointestinal Tract: Evaluation Based on In Vivo Luminal Concentration-Time Profile of Cilostazol, a Poorly Soluble Drug, and Solubilizers.

    PubMed

    Tanaka, Yusuke; Kubota, Atsuo; Matsuo, Akira; Kawakami, Ayaka; Kamizi, Hiroki; Mochigoe, Akane; Hiramachi, Takahiro; Kasaoka, Satoshi; Yoshikawa, Hiroshi; Nagata, Shunji

    2016-09-01

    The purpose of this study was to evaluate the effect of absorption behavior of solubilizers on drug dissolution in the gastrointestinal tract. After oral administration of FITC-dextran (FD-10), a nonabsorbable marker, and cilostazol (CZ), a low-solubility drug, with or without solubilizers (dimethyl sulfoxide [DMSO], and d-α-tocopherol polyethylene glycol 1000 succinate [TPGS]), the in vivo rat luminal concentrations of these compounds were determined by direct sampling of residual water in each segment of the gastrointestinal tract. DMSO was rapidly absorbed and not detected in the middle small intestine. Conversely, the TPGS concentration increased by 1.5- and 2-fold relative to the initial dose concentration in the middle and lower small intestine, respectively, owing to condensation. Then, normalized area under the luminal concentration-time curve of solid CZ was calculated from the luminal concentration-time profiles of FD-10 and solid CZ to evaluate in vivo dissolution behavior of CZ. The dissolution of CZ was marked when administered with TPGS compared with that when administered with DMSO, especially in the lower small intestine. This clearly indicates that absorbability of solubilizers is one of the important factors in determining the solubilizing effect. These findings may be beneficial to development of oral lipophilic drugs. PMID:27025982

  17. Database Extraction of Metabolite Information of Drug Candidates: Analysis of 27 AstraZeneca Compounds with Human Absorption, Distribution, Metabolism, and Excretion Data.

    PubMed

    Iegre, Jessica; Hayes, Martin A; Thompson, Richard A; Weidolf, Lars; Isin, Emre M

    2016-05-01

    As part of the drug discovery and development process, it is important to understand the human metabolism of a candidate drug prior to clinical studies. Preclinical in vitro and in vivo experiments across species are conducted to build knowledge concerning human circulating metabolites in preparation for clinical studies; therefore, the quality of these experiments is critical. Within AstraZeneca, all metabolite identification (Met-ID) information is stored in a global database using ACDLabs software. In this study, the Met-ID information derived from in vitro and in vivo studies for 27 AstraZeneca drug candidates that underwent human absorption, distribution, metabolism, and excretion studies was extracted from the database. The retrospective analysis showed that 81% of human circulating metabolites were previously observed in preclinical in vitro and/or in vivo experiments. A detailed analysis was carried out to understand which human circulating metabolites were not captured in the preclinical experiments. Metabolites observed in human hepatocytes and rat plasma but not seen in circulation in humans (extraneous metabolites) were also investigated. The majority of human specific circulating metabolites derive from multistep biotransformation reactions that may not be observed in in vitro studies within the limited time frame in which cryopreserved hepatocytes are active. Factors leading to the formation of extraneous metabolites in preclinical studies seemed to be related to species differences with respect to transporter activity, secondary metabolism, and enzyme kinetics. This retrospective analysis assesses the predictive value of Met-ID experiments and improves our ability to discriminate between metabolites expected to circulate in humans and irrelevant metabolites seen in preclinical studies. PMID:26868617

  18. High performance sapphire windows

    NASA Technical Reports Server (NTRS)

    Bates, Stephen C.; Liou, Larry

    1993-01-01

    High-quality, wide-aperture optical access is usually required for the advanced laser diagnostics that can now make a wide variety of non-intrusive measurements of combustion processes. Specially processed and mounted sapphire windows are proposed to provide this optical access to extreme environment. Through surface treatments and proper thermal stress design, single crystal sapphire can be a mechanically equivalent replacement for high strength steel. A prototype sapphire window and mounting system have been developed in a successful NASA SBIR Phase 1 project. A large and reliable increase in sapphire design strength (as much as 10x) has been achieved, and the initial specifications necessary for these gains have been defined. Failure testing of small windows has conclusively demonstrated the increased sapphire strength, indicating that a nearly flawless surface polish is the primary cause of strengthening, while an unusual mounting arrangement also significantly contributes to a larger effective strength. Phase 2 work will complete specification and demonstration of these windows, and will fabricate a set for use at NASA. The enhanced capabilities of these high performance sapphire windows will lead to many diagnostic capabilities not previously possible, as well as new applications for sapphire.

  19. Adaptive Liquid Crystal Windows

    SciTech Connect

    Taheri, Bahman; Bodnar, Volodymyr

    2011-12-31

    Energy consumption by private and commercial sectors in the U.S. has steadily grown over the last decade. The uncertainty in future availability of imported oil, on which the energy consumption relies strongly, resulted in a dramatic increase in the cost of energy. About 20% of this consumption are used to heat and cool houses and commercial buildings. To reduce dependence on the foreign oil and cut down emission of greenhouse gases, it is necessary to eliminate losses and reduce total energy consumption by buildings. To achieve this goal it is necessary to redefine the role of the conventional windows. At a minimum, windows should stop being a source for energy loss. Ideally, windows should become a source of energy, providing net gain to reduce energy used to heat and cool homes. It is possible to have a net energy gain from a window if its light transmission can be dynamically altered, ideally electronically without the need of operator assistance, providing optimal control of the solar gain that varies with season and climate in the U.S. In addition, the window must not require power from the building for operation. Resolution of this problem is a societal challenge and of national interest and will have a broad global impact. For this purpose, the year-round, allclimate window solution to provide an electronically variable solar heat gain coefficient (SHGC) with a wide dynamic range is needed. AlphaMicron, Inc. (AMI) developed and manufactured 1ft × 1ft prototype panels for the world’s first auto-adjusting Adaptive Liquid Crystal Windows (ALCWs) that can operate from sunlight without the need for external power source and demonstrate an electronically adjustable SHGC. This novel windows are based on AlphaMicron’s patented e-Tint® technology, a guesthost liquid crystal system implemented on flexible, optically clear plastic films. This technology is suitable both for OEM and aftermarket (retro-fitting) lamination to new and existing windows. Low level of

  20. In-vivo measurements of penetration depth, oxygenation, and drug concentration using broadband absorption spectroscopy in human tissues before and after photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Wang, Hsing-Wen; Zhu, Timothy C.; Solonenko, Michael; Hahn, Stephen M.; Metz, James M.; Dimofte, Andrea; Mile, Jermy; Yodh, Arjun G.

    2003-06-01

    Photodynamic therapy (PDT) employs a combination of photosensitizing chemical, light, and oxygen Knowledge of tissue optical properties, including absorption (μa) and reduce scattering coefficients (μs"), makes possible to derive blood oxygen saturation, light penetration depth, and drug concentration, which are important to ensure PDT treatment efficacy at the specific wavelengths. We have developed an absorption spectroscopy system to measure μa and μs" in the spectral range 600-800nm using a contact linear probe with a source fiber and multiple source-detector separation distances less than 1 cm. The μa and μs" were recovered based on diffusion approximations of the photon transport equation. We measured tissue optical properties among various organs of patients with intraperitoneal malignancies for an on-going Phase II PDT protocol. The results from 12 patients showed various effective penetration depth from site to site and from organ to organ. The percentage oxygen saturation (%StO2) are similar before and after PDT. Before PDT, meff (mean (standard deviation) (number of patients)) in cm-1 at 630nm are 2.4 (0.2) (12) in small bowel, 2.2(0.4) (9) in large bowel, 4.2(2.7) (7) in tumor, 3.3 (0.3) (10) in peritoneum, 2.7 (0.3) (11) in skin, and 10.1 (0.6) (10) in liver. %StO2 is 60-80% for most organs but 30-40% for tumor.

  1. "Stained Glass" Landscape Windows

    ERIC Educational Resources Information Center

    Vannata, Janine

    2008-01-01

    Both adults and children alike marvel at the grand vivid stained-glass windows created by American artist Louis Comfort Tiffany. Today he is commonly recognized as one of America's most influential designers and artists throughout the last nineteenth and early twentieth century. In the lesson described in this article, students created their own…

  2. Exploring Shop Window Displays

    ERIC Educational Resources Information Center

    Christopoulou, Martha

    2011-01-01

    Using visual resources from everyday life in art lessons can enrich students' knowledge about the creation of visual images, artifacts, and sites, and develop their critical understanding about the cultural impact of these images and their effects on people's lives. Through examining an exhibition in the windows of Selfridges department store in…

  3. Opening the Literature Window

    ERIC Educational Resources Information Center

    Jago, Carol

    2012-01-01

    Great literature gives students a window to other places and times, but it often requires students to step outside their comfort zones and take on challenges they wouldn't usually attempt. Unfortunately, research shows that many schools are not assigning literature that pushes students beyond their current reading level. Jago encourages teachers…

  4. Foamglass solar window collector

    NASA Astrophysics Data System (ADS)

    Grande, P. C.

    Solar heating of a living area by means of a foamglass window collector is reported. The collector was built with readily available materials available at most local hardware stores. The payback period was found to be 3.7 years, slightly longer than anticipated.

  5. Apollo window meteoroid experiment

    NASA Technical Reports Server (NTRS)

    Cour-Palais, B. G.; Flaherty, R. E.; Brown, M. L.

    1972-01-01

    Apollo window meteoroid experiment for obtaining data from crater counts and analysis of meteoroid residue combined with fused glass in described. A preliminary estimate of the flux resulting from seven Apollo spacecraft is found to be in agreement with the Surveyor 3 data, but is lower than the model environment.

  6. Software: Looking Through WINDOW.

    ERIC Educational Resources Information Center

    Classroom Computer News, 1983

    1983-01-01

    Reviews the educational value, design quality, and ease of use of "WINDOW," an educational "magazine" on a disk for the Apple II/IIe microcomputer. Indicates that the articles, software reviews, and other informative material are greatly enhanced by sound, graphics, and the chance to try out reviewed programs. (JN)

  7. Candles in Our Windows

    ERIC Educational Resources Information Center

    McGrath, Kathryn

    2005-01-01

    "Candles in Our Windows"--also titled "Nightlights"--is a play developed for elementary and middle school students about how residents in Billings, Montana, took a stand against hate. Last March, the 6th-grade students of Woodland Elementary School in New Jersey performed an early version of the play based on a children's book, "The Christmas…

  8. Migration to Windows NT.

    ERIC Educational Resources Information Center

    Doles, Daniel T.

    In the constantly changing world of technology, migration is not only inevitable but many times necessary for survival, especially when the end result is simplicity for both users and IT support staff. This paper describes the migration at Franklin College (Indiana). It discusses the reasons for selecting Windows NT, the steps taken to complete…

  9. Windows to Art Excitement.

    ERIC Educational Resources Information Center

    Laird, Shirley; Crumpecker, Cheryl

    2003-01-01

    Describes an art project that aimed to bring more attention to an art program. Explains that the students created themed murals on the windows of the art classroom, such as a "Jungle,""Ocean,""Masterpiece Paintings," and "Rainforest Tree Frogs." Discusses how the murals were created. (CMK)

  10. Microwave Workshop for Windows.

    ERIC Educational Resources Information Center

    White, Colin

    1998-01-01

    "Microwave Workshop for Windows" consists of three programs that act as teaching aid and provide a circuit design utility within the field of microwave engineering. The first program is a computer representation of a graphical design tool; the second is an accurate visual and analytical representation of a microwave test bench; the third is a more…

  11. Windows and lighting program

    SciTech Connect

    Not Available

    1990-06-01

    More than 30% of all energy use in buildings is attributable to two sources: windows and lighting. Together they account for annual consumer energy expenditures of more than $50 billion. Each affects not only energy use by other major building systems, but also comfort and productivity -- factors that influence building economics far more than does direct energy consumption alone. Windows play a unique role in the building envelope, physically separating the conditioned space from the world outside without sacrificing vital visual contact. Throughout the indoor environment, lighting systems facilitate a variety of tasks associated with a wide range of visual requirements while defining the luminous qualities of the indoor environment. Windows and lighting are thus essential components of any comprehensive building science program. Despite important achievements in reducing building energy consumption over the past decade, significant additional savings are still possible. These will come from two complementary strategies: (1) improve building designs so that they effectively apply existing technologies and extend the market penetration of these technologies; and (2) develop advanced technologies that increase the savings potential of each application. Both the Windows and Daylighting Group and the Lighting System Research Group have made substantial contributions in each of these areas, and continue to do so through the ongoing research summarized here. 23 refs., 16 figs.

  12. Windows into Art Classrooms.

    ERIC Educational Resources Information Center

    Grauer, Kit, Ed.

    1995-01-01

    An editorial by Kit Grauer introduces this collection of articles which establish that there is no such thing as a simple definition of art education even within one culture, and that people's views can be reflected by art educators across the world. The first article, "A Window on Three Singapore Art Classrooms" (Jane Chia; John Matthews; Paul…

  13. Sliding window construction

    SciTech Connect

    Klompenburg, M.V.

    1987-07-28

    A window assembly is described in a window frame. The frame includes a head, a sill, and opposite jambs, the assembly comprising: first and second sashes each having interior and exterior surfaces, a top, a bottom, and opposite first and second sides extending between the top and the bottom: the first sash being laterally movably within the window frame between a closed position and an open position wherein the first sash is substantially in a non-planar position relative to the second sash; track means extending along one of the sill or head of the window frame; first track follower means connected to one of the top or the bottom of the first sash adjacent the first side and cooperating with the track means for supporting and guiding the first sash during lateral movement between the open and closed positions; and the track means having an opening for releasing the track follower means for cooperation only when the first sash is in the open position such that the first sash is pivotal about a vertical axis adjacent the second side between the open position and a maintenance position.

  14. Superconductive radiofrequency window assembly

    DOEpatents

    Phillips, Harry Lawrence; Elliott, Thomas S.

    1998-01-01

    The present invention is a superconducting radiofrequency window assembly for use in an electron beam accelerator. The srf window assembly (20) has a superconducting metal-ceramic design. The srf window assembly (20) comprises a superconducting frame (30), a ceramic plate (40) having a superconducting metallized area, and a superconducting eyelet (50) for sealing plate (40) into frame (30). The plate (40) is brazed to eyelet (50) which is then electron beam welded to frame (30). A method for providing a ceramic object mounted in a metal member to withstand cryogenic temperatures is also provided. The method involves a new metallization process for coating a selected area of a ceramic object with a thin film of a superconducting material. Finally, a method for assembling an electron beam accelerator cavity utilizing the srf window assembly is provided. The procedure is carried out within an ultra clean room to minimize exposure to particulates which adversely affect the performance of the cavity within the electron beam accelerator.

  15. Superconducting radiofrequency window assembly

    DOEpatents

    Phillips, Harry L.; Elliott, Thomas S.

    1997-01-01

    The present invention is a superconducting radiofrequency window assembly for use in an electron beam accelerator. The srf window assembly (20) has a superconducting metal-ceramic design. The srf window assembly (20) comprises a superconducting frame (30), a ceramic plate (40) having a superconducting metallized area, and a superconducting eyelet (50) for sealing plate (40) into frame (30). The plate (40) is brazed to eyelet (50) which is then electron beam welded to frame (30). A method for providing a ceramic object mounted in a metal member to withstand cryogenic temperatures is also provided. The method involves a new metallization process for coating a selected area of a ceramic object with a thin film of a superconducting material. Finally, a method for assembling an electron beam accelerator cavity utilizing the srf window assembly is provided. The procedure is carried out within an ultra clean room to minimize exposure to particulates which adversely affect the performance of the cavity within the electron beam accelerator.

  16. Study of noise transmission through double wall aircraft windows

    NASA Technical Reports Server (NTRS)

    Vaicaitis, R.

    1983-01-01

    Analytical and experimental procedures were used to predict the noise transmitted through double wall windows into the cabin of a twin-engine G/A aircraft. The analytical model was applied to optimize cabin noise through parametric variation of the structural and acoustic parameters. The parametric study includes mass addition, increase in plexiglass thickness, decrease in window size, increase in window cavity depth, depressurization of the space between the two window plates, replacement of the air cavity with a transparent viscoelastic material, change in stiffness of the plexiglass material, and different absorptive materials for the interior walls of the cabin. It was found that increasing the exterior plexiglass thickness and/or decreasing the total window size could achieve the proper amount of noise reduction for this aircraft. The total added weight to the aircraft is then about 25 lbs.

  17. Double window viewing chamber assembly

    NASA Technical Reports Server (NTRS)

    Keller, V. W. (Inventor); Owen, R. B. (Inventor); Elkins, B. R. (Inventor); White, W. T. (Inventor)

    1986-01-01

    A viewing chamber which permits observation of a sample retained therein includes a pair of double window assemblies mounted in opposed openings in the walls thereof so that a light beam can directly enter and exit from the chamber. A flexible mounting arrangement for the outer windows of the window assemblies enables the windows to be brought into proper alignment. An electrical heating arrangement prevents fogging of the outer windows whereas desiccated air in the volume between the outer and inner windows prevents fogging of the latter.

  18. VIEW OF THREE SOUTH FACING STAINED GLASS WINDOWS. THESE WINDOWS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF THREE SOUTH FACING STAINED GLASS WINDOWS. THESE WINDOWS ARE LOCATED ADJACENT TO THE ALTER. - U.S. Naval Base, Pearl Harbor, Chapel, Corner of Oakley & Nimitz Street, Pearl City, Honolulu County, HI

  19. VIEW OF THREE NORTH FACING STAINED GLASS WINDOWS. THESE WINDOWS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF THREE NORTH FACING STAINED GLASS WINDOWS. THESE WINDOWS ARE LOCATED ADJACENT TO THE ALTAR. - U.S. Naval Base, Pearl Harbor, Chapel, Corner of Oakley & Nimitz Street, Pearl City, Honolulu County, HI

  20. VIEW OF THREE NORTH FACING STAINED GLASS WINDOWS. THESE WINDOWS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF THREE NORTH FACING STAINED GLASS WINDOWS. THESE WINDOWS ARE LOCATED JUST BELOW THE CHOIR LOFT. - U.S. Naval Base, Pearl Harbor, Chapel, Corner of Oakley & Nimitz Street, Pearl City, Honolulu County, HI

  1. details: window jamb from first period of construction; window jamb, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    details: window jamb from first period of construction; window jamb, sill profile, and transom profile from second period of construction - Joseph Poffenberger Farm, House, 17834 Mansfield Avenue, Sharpsburg, Washington County, MD

  2. Optimized ECR plasma apparatus with varied microwave window thickness

    DOEpatents

    Berry, L.A.

    1995-11-14

    The present invention describes a technique to control the radial profile of microwave power in an ECR plasma discharge. In order to provide for a uniform plasma density to a specimen, uniform energy absorption by the plasma is desired. By controlling the radial profile of the microwave power transmitted through the microwave window of a reactor, the profile of the transmitted energy to the plasma can be controlled in order to have uniform energy absorption by the plasma. An advantage of controlling the profile using the window transmission characteristics is that variations to the radial profile of microwave power can be made without changing the microwave coupler or reactor design. 9 figs.

  3. Optimized ECR plasma apparatus with varied microwave window thickness

    DOEpatents

    Berry, Lee A.

    1995-01-01

    The present invention describes a technique to control the radial profile of microwave power in an ECR plasma discharge. In order to provide for a uniform plasma density to a specimen, uniform energy absorption by the plasma is desired. By controlling the radial profile of the microwave power transmitted through the microwave window of a reactor, the profile of the transmitted energy to the plasma can be controlled in order to have uniform energy absorption by the plasma. An advantage of controlling the profile using the window transmission characteristics is that variations to the radial profile of microwave power can be made without changing the microwave coupler or reactor design.

  4. Optical Absorption in Liquid Semiconductors

    NASA Astrophysics Data System (ADS)

    Bell, Florian Gene

    An infrared absorption cell has been developed which is suitable for high temperature liquids which have absorptions in the range .1-10('3) cm('-1). The cell is constructed by clamping a gasket between two flat optical windows. This unique design allows the use of any optical windows chemically compatible with the liquid. The long -wavelength limit of the measurements is therefore limited only by the choice of the optical windows. The thickness of the cell can easily be set during assembly, and can be varied from 50 (mu)m to .5 cm. Measurements of the optical absorption edge were performed on the liquid alloy Se(,1-x)Tl(,x) for x = 0, .001, .002, .003, .005, .007, and .009, from the melting point up to 475(DEGREES)C. The absorption was found to be exponential in the photon energy over the experimental range from 0.3 eV to 1.2 eV. The absorption increased linearly with concentration according to the empirical relation (alpha)(,T)(h(nu)) = (alpha)(,1) + (alpha)(,2)x, and the absorption (alpha)(,1) was interpreted as the absorption in the absence of T1. (alpha)(,1) also agreed with the measured absorption in 100% Se at corresponding temperatures and energies. The excess absorption defined by (DELTA)(alpha) = (alpha)(,T)(h(nu))-(alpha)(,1) was interpreted as the absorption associated with Tl and was found to be thermally activated with an activation energy E(,t) = 0.5 eV. The exponential edge is explained as absorption on atoms immersed in strong electric fields surrounding ions. The strong fields give rise to an absorption tail similar to the Franz-Keldysh effect. A simple calculation is performed which is based on the Dow-Redfield theory of absorption in an electric field with excitonic effects included. The excess absorption at low photon energies is proportional to the square of the concentration of ions, which are proposed to exist in the liquid according to the relation C(,i) (PROPORTIONAL) x(' 1/2)(.)e('-E)t('/kT), which is the origin of the thermal activation

  5. Lens window simplifies TDL housing

    NASA Technical Reports Server (NTRS)

    Robinson, D. M.; Rowland, C. W.

    1979-01-01

    Lens window seal in tunable-diode-laser housing replaces plan parallel window. Lens seals housing and acts as optical-output coupler, thus eliminating need for additional reimaging or collimating optics.

  6. A Window-Washing Challenge

    ERIC Educational Resources Information Center

    Roman, Harry T.

    2010-01-01

    Skyscrapers sure do have a lot of windows, and these windows are cleaned and checked regularly. All this takes time, money, and puts workers at potential risk. Might there be a better way to do it? In this article, the author discusses a window-washing challenge and describes how students can tackle this task, pick up the challenge, and creatively…

  7. Beam Window for Pressure Chambers

    NASA Technical Reports Server (NTRS)

    Bransford, J. W.; Austin, J. G., Jr.

    1985-01-01

    Window resists products of combustion experiments. Sodium chloride window seals over chamber pressures from 0.1 to 13.8 MPa while absorbing minimal energy from CO2 laser beam that passes through it into chamber. Window inexpensive and easily replacable.

  8. Windows: The Benefits Are Clear.

    ERIC Educational Resources Information Center

    Sturgeon, Julie

    1999-01-01

    Discusses the importance of specifying windows in a school renovation or building project in order to energize a campus. Explains how windows are psychologically uplifting, how glass accentuates excitement and its shapes signal stability, and how windows convey the institution's confidence in the present. (GR)

  9. Feasibility study of a cryogenically cooled window for high-power gyrotrons

    SciTech Connect

    Haste, G.R.; Kimrey, H.D.; Prosise, J.D.

    1986-07-01

    Single-crystal sapphire is currently in use as the material for output windows in high-power microwave tubes, particularly gyrotrons. These windows are currently being cooled by fluorocarbon fluids at near-room temperatures. There are, however, several advantages in operating the window at very low temperatures: less absorption and consequent heating of the window, greater material strength, improved resistance to crack formation, greater thermal conductivity, and reduced thermal expansion. Operation at cryogenic temperatures is shown to be feasible. The output power, which is currently limited by window constraints, could be increased by an order of magnitude or more.

  10. Determination of total arsenic by batch hydride generation atomic absorption spectrometry in injectable drugs containing high levels of Sb(V) as N-methylglucamine antimonate

    NASA Astrophysics Data System (ADS)

    Flores, Érico Marlon de Moraes; Barcelos da Silva, Fabiana E.; Santos, Eliane Pereira dos; Paula, Fávero Reisdorfer; Barin, Juliano Smanioto; Zanella, Renato; Dressler, Valderi Luiz; Bittencourt, Celso Figueiredo

    2002-12-01

    A procedure for the determination of arsenic by batch hydride generation atomic absorption spectrometry (HG AAS) in commercial samples of injectable drugs, containing high concentrations of Sb(V), is described. The procedure is based on the complexing effect for Sb of citric, oxalic and acetic acids as reaction media. Aqua regia was used for sample digestion prior to As determination by HG AAS. The following experimental conditions for the determination of total As, as As(V), were evaluated: the acid medium and its concentration, sodium tetrahydroborate concentration, purge time, and influence of the different oxidation states of As. The effect of the delay time after mixing of sample and acid solution was also studied. Optimized conditions were: 10% (m/v) citric acid, 1.5% (m/v) sodium tetrahydroborate solution and 30 s for purge time. A delay time of 1 h was required after the digested sample had been mixed with citric acid, before As determination could be carried out. No interference on As(III) and As(V) signals was observed in the presence of up to 1 mg Sb(V). The tolerance limits for Ni(II), Cu(II) and Pb(II) were 1 mg, 100 μg and 100 μg, respectively. Recovery tests for As(III) and As(V) resulted in values between 97 and 101%. Characteristic mass and detection limit (3σ), using the recommended conditions, were 0.52 and 0.8 ng, respectively, for total As.

  11. Proximal Roux-en-Y Gastric Bypass Alters Drug Absorption Pattern But Not Systemic Exposure of CYP3A4 and P-glycoprotein Substrates

    PubMed Central

    Chan, Lingtak-Neander; Lin, Yvonne S.; Tay-Sontheimer, Jessica C.; Trawick, Dorothy; Oelschlager, Brant K.; Flum, David R.; Patton, Kristen K.; Shen, Danny D.; Horn, John R.

    2015-01-01

    Study Objectives To evaluate the effect of Roux-en-Y gastric bypass surgery (RYGB) on the pharmacokinetics of midazolam (a CYP3A4 substrate) and digoxin (a P-glycoprotein substrate). Design Prospective, nonblinded, longitudinal, single-dose pharmacokinetic study in three phases: presurgery baseline and postoperative assessments at 3 and 12 months. Patients Twelve obese patients meeting current standards for bariatric surgery. Measurements and Main Results At each study visit, patients received a single dose of oral digoxin and midazolam at 8 a.m. Blood samples were collected at regular intervals for 24 hours after dosing. Continuous 12-lead electrocardiogram (EKG), heart rate, blood pressure, and respiratory rate were monitored, and pharmacokinetic parameters from the three visits were compared. The peak plasma concentration (Cmax) of midazolam increased by 66% and 71% at 3- and 12-month post-RYGB (p=0.017 and p=0.001, respectively), whereas the median time to peak concentration (Tmax) was reduced by 50%. The mean Cmax for 1′-hydroxymidazolam increased by 87% and 80% at 3 and 12 months (p=0.001 and p<0.001, respectively). However, neither the area under the concentration-time curve (AUC) for midazolam nor the metabolite-to-parent AUC ratio changed significantly over time. For digoxin, the median Tmax decreased from 40 minutes at baseline to 30 and 20 minutes at 3 and 12 months, respectively. The mean AUC for digoxin, heart rate, and EKG patterns were similar across the three study phases. Conclusion Contemporary proximal RYGB increases the rate of drug absorption without significantly changing the overall exposure to midazolam and digoxin. The Cmax of a CYP3A4 substrate with a high extraction ratio was substantially increased after RYGB. PMID:25757445

  12. Study on the interactions of antiemetic drugs and 12-tungstophosphoric acid by absorption and resonance Rayleigh scattering spectra and their analytical applications

    NASA Astrophysics Data System (ADS)

    Wang, Yaqiong; Liu, Shaopu; Liu, Zhongfang; Yang, Jidong; Hu, Xiaoli

    2013-03-01

    In 0.1 mol L-1 HCl medium, antiemetic drugs (ATM), such as granisetron hydrochloride (GS) and tropisetron hydrochloride (TS), reacted with H3PW12O40·nH2O and formed 3:1 ion-association complex of [(ATM)3PW12O40], then self-aggregated into nanoparticles-[(ATM)3PW12O40]n with an average size of 100 nm. The reaction resulted in the enhancement of resonance Rayleigh scattering (RRS) and the absorption spectra. The increments of scattering intensity (ΔIRRS) and the change of absorbance (ΔA) were both directly proportional to the concentrations of ATM in certain ranges. Accordingly, two new RRS and spectrophotometric methods were proposed for ATM detection. The detection limits (3σ) of GS and TS were 3.2 ng mL-1 and 4.0 ng mL-1(RRS method), 112.5 ng mL-1 and 100.0 ng mL-1(spectrophotometric method). These two methods were applied to determine GS in orally disintegrating tablets and the results were in good agreement with the official method. The ground-state geometries and electronic structures of GS and TS were optimized by the hybrid density functional theory (DFT) method and the shape of [(ATM)3PW12O40]n was characterized by atomic force microscopy (AFM). Take the RRS method with higher sensitivity as an example, the reaction mechanism and the reasons for enhancement of scattering were discussed.

  13. Effect of food intake and co-administration of placebo self-nanoemulsifying drug delivery systems on the absorption of cinnarizine in healthy human volunteers.

    PubMed

    Christiansen, Martin Lau; Holm, Rene; Abrahamsson, Bertil; Jacobsen, Jette; Kristensen, Jakob; Andersen, Jens Rikardt; Müllertz, Anette

    2016-03-10

    Positive food effects may be observed for low aqueous soluble compounds, these effects could potentially be circumvented using lipid based formulations. However, as all compounds are not chemically stable in lipid based systems, alternative dosage regimes could be investigated to evade the stability issue. The two aims for this present study were therefore; i) to investigate if a nutritional drink, Fresubin Energy®, could induce food effect in humans for the poorly soluble compound cinnarizine; and ii) to investigate if co-administration of a self-nano-emulsifying drug delivery systems (SNEDDS) with a conventional cinnarizine tablet could reduce the observed food-effect. A commercial conventional cinnarizine tablet was dosed to 10 healthy volunteers in a cross-over design in both fasted and fed state, with and without co-administration of a SNEDDS, with a one week wash-out period between dosing. The fed state was induced using a nutritional drink (Fresubin Energy®) and gastric emptying was assessed by administration of paracetamol as a marker. The pharmacokinetic analysis showed that the nutritional drink delayed the uptake and increased the fraction of absorbed cinnarizine, indicative of a food effect on the compound. This was in agreement with a previous dog study and indicates that the nutritional drink can be used for inducing the same level of food effect in humans. Though not statistically significant, the co-administration of SNEDDS exhibited a tendency towards a reduction of the observed food effect and an increased absorption of cinnarizine in the fasted state; based upon the individual ratios, which was not reflected in the mean data. However, the co-administration of SNEEDS in the fasted state, also induce a slower gastric emptying rate, which was observed as a delayed tmax for both cinnarizine and paracetamol. PMID:26775868

  14. Decades of research in drug targeting to the upper gastrointestinal tract using gastroretention technologies: where do we stand?

    PubMed

    Awasthi, Rajendra; Kulkarni, Giriraj T

    2016-01-01

    A major constraint in oral controlled release drug delivery is that not all the drug candidates are absorbed uniformly throughout the gastrointestinal tract (GIT). Drugs having "absorption window" are absorbed in a particular portion of GIT only or are absorbed to a different extent in various segments of the GIT. Thus, only the drug released in the region preceding and in close vicinity to the absorption window is available for absorption. The drug must be released from the dosage form in solution form; otherwise, it is generally not absorbed. Hence, much research has been dedicated to the development of gastroretentive drug delivery systems that may optimize the bioavailability and subsequent therapeutic efficacy of such drugs, as these systems have unique properties to bypass the gastric emptying process. These systems show excellent in vitro results but fail to give desirable in vivo performance. During the last 2-3 decades, researchers from the academia and industries are giving considerable importance in this field. Unfortunately, till date, few so-called gastroretentive dosage forms have been brought to the market in spite of numerous academic publications. The manuscript considers strategies that are commonly used in the development of gastroretentive drug delivery systems with a special attention on various parameters, which needs to be monitored during formulation development. PMID:25026414

  15. Sunlight Responsive Thermochromic Window System

    SciTech Connect

    Millett, F,A; Byker,H, J

    2006-10-27

    Pleotint has embarked on a novel approach with our Sunlight Responsive Thermochromic, SRT™, windows. We are integrating dynamic sunlight control, high insulation values and low solar heat gain together in a high performance window. The Pleotint SRT window is dynamic because it reversibly changes light transmission based on thermochromics activated directly by the heating effect of sunlight. We can achieve a window package with low solar heat gain coefficient (SHGC), a low U value and high insulation. At the same time our windows provide good daylighting. Our innovative window design offers architects and building designers the opportunity to choose their desired energy performance, excellent sound reduction, external pane can be self-cleaning, or a resistance to wind load, blasts, bullets or hurricanes. SRT windows would provide energy savings that are estimated at up to 30% over traditional window systems. Glass fabricators will be able to use existing equipment to make the SRT window while adding value and flexibility to the basic design. Glazing installers will have the ability to fit the windows with traditional methods without wires, power supplies and controllers. SRT windows can be retrofit into existing buildings,

  16. Molecular organization of the antifungal and anticancer drug 2-(2,4-dihydroxyphenylo)-5,6-dichlorobenzothiazole (dHBBT) in solution and in lipid membranes studied by means of electronic absorption spectroscopy.

    PubMed

    Gagoś, Mariusz; Niewiadomy, Andrzej; Gruszecki, Wiesław I

    2004-10-25

    2-(2,4-Dihydroxyphenylo)-5,6-dichlorobenzthiazole (dHBBT) is a new drug from the group of chemical compounds characterized by documented antifungal, antibacterial, cytostatic as well as antitumour activity. Despite general knowledge regarding pharmacological importance of dHBBT its interaction to biomembranes has not been investigated. In this work, we present the electronic absorption spectroscopic study on molecular organization of dHBBT in organic solvents and on its localization and molecular organization within model lipid membranes formed with dipalmitoylphosphatidylcholine (DPPC). The spectroscopic measurements are interpreted within the framework of the exciton splitting theory. It is concluded that complex absorption spectrum of dHBBT both in the organic solvents and incorporated to DPPC represents superposition of two spectral forms: representing monomers and hypsochromically shifted spectrum representing molecular dimers. Analysis of the temperature dependencies of the absorption spectra of dHBBT incorporated to DPPC liposomes suggests localization of the drug in the polar head-group region of the membrane or in the region of the polar-nonpolar interface. Linear dichroism measurements of dHBBT incorporated to DPPC multibilayers reveal roughly vertical orientation of the drug molecules with respect to the plane of the membrane. A model is presented of molecular organization of dHBBT in lipid membranes. Potential effects of dHBBT on membrane physical properties is briefly discussed. PMID:15488713

  17. Windows on the axion

    SciTech Connect

    Turner, M.S.

    1989-04-01

    Peccei-Quinn symmetry with attendant axion is a most compelling, and perhaps the most minimal, extension of the standard model, as it provides a very elegant solution to the nagging strong CP-problem associated with the THETA vacuum structure of QCD. However, particle physics gives little guidance as to the axion mass; a priori, the plausible values span the range: 10/sup /minus/12/ eV /approx lt/ m/sub a/ /approx lt/ 10/sup 6/ eV, some 18 orders-of-magnitude. Axions have a host of interesting astrophysical and cosmological effects, including, modifying the evolution of stars of all types (our sun, red giants, white dwarfs, and neutron stars), contributing significantly to the mass density of the Universe today, and producing detectable line radiation through the decays of relic axions. Consideration of these effects has probed 14 orders-of-magnitude in axion mass, and has left open only two windows for further exploration: 10/sup /minus/6/ eV /approx lt/ m/sub a/ /approx lt/ 10/sup /minus/3/ eV and 1 eV /approx lt/ m/sub a/ /approx lt/ 5 eV (hadronic axions only). Both these windows are accessible to experiment, and a variety of very interesting experiments, all of which involve ''heavenly axions,'' are being planned or are underway. 58 refs., 6 figs., 1 tab.

  18. Window cleaner poisoning

    MedlinePlus

    ... Poisoning and Drug Overdose . 4th ed. Philadelphia, PA: Elsevier Saunders; 2007:chap 32. Mycyk MB. Toxic alcohols. ... JG, ed. Emergency Medicine . 2nd ed. Philadelphia, PA: Elsevier Saunders; 2013:chap 151. White SR. Toxic alcohols. ...

  19. Window cleaner poisoning

    MedlinePlus

    Jacobsen D, Hovda KE. Methanol, ethylene glycol, and other toxic alcohols. In: Shannon MW, Borron SW, Burns MJ, eds. Haddad and Winchester's Clinical Management of Poisoning and Drug Overdose . 4th ed. Philadelphia, ...

  20. Switchable Solar Window Devices Based on Polymer Dispersed Liquid Crystals

    NASA Astrophysics Data System (ADS)

    Murray, Joseph; Ma, Dakang; Munday, Jeremy

    Windows are an interesting target for photovoltaics due to the potential for large area of deployment and because glass is already a ubiquitous component of solar cell devices. Many demonstrations of solar windows in recent years have used photovoltaic devices which are semitransparent in the visible region. Much research has focused on enhancing device absorption in the UV and IR ranges as a means to circumvent the basic tradeoff between efficiency and transparency to visible light. Use of switchable solar window is a less investigated alternative approach; these windows utilize the visible spectrum but can toggle between high transparency and high efficiency as needed. We present a novel switchable solar window device based on Polymer Dispersed Liquid Crystals (PDLC). By applying an electric field to the PDLC layer, the device can be switched from an opaque, light diffusing, efficient photovoltaic cell to a clear, transparent window. In the off state (i.e. scattering state), these devices have the added benefits of increased reflectivity for reduced lighting and cooling costs and haze for privacy. Further, we demonstrate that these windows have the potential for self-powering due to the very low power required to maintain the on, or high transparency, state. Support From: University of Maryland and Maryland Nano-center and its Fablab.

  1. Window defect planar mapping technique

    NASA Technical Reports Server (NTRS)

    Minton, F. R.; Minton, U. O. (Inventor)

    1976-01-01

    A method of planar mapping defects in a window having an edge surface and a planar surface. The method is comprised of steps for mounting the window on a support surface. Then a light sensitive paper is placed adjacent to the window surface. A light source is positioned adjacent to the window edge. The window is then illuminated with the source of light for a predetermined interval of time. Defects on the surface of the glass, as well as in the interior of the glass are detected by analyzing the developed light sensitive paper. The light source must be in the form of optical fibers or a light tube whose light transmitting ends are placed near the edge surface of the window.

  2. Analysis of the impact of controlled release formulations on oral drug absorption, gut wall metabolism and relative bioavailability of CYP3A substrates using a physiologically-based pharmacokinetic model.

    PubMed

    Olivares-Morales, Andrés; Kamiyama, Yoshiteru; Darwich, Adam S; Aarons, Leon; Rostami-Hodjegan, Amin

    2015-01-25

    Controlled release (CR) formulations are usually designed to achieve similar exposure (AUC) levels as the marketed immediate release (IR) formulation. However, the AUC is often lower following CR compared to IR formulations. There are a few exceptions when the CR formulations have shown higher AUC. This study investigated the impact of CR formulations on oral drug absorption and CYP3A4-mediated gut wall metabolism. A review of the current literature on relative bioavailability (Frel) between CR and IR formulations of CYP3A substrates was conducted. This was followed by a systematic analysis to assess the impact of the release characteristics and the drug-specific factors (including metabolism and permeability) on oral bioavailability employing a physiologically-based pharmacokinetic (PBPK) modelling and simulation approach. From the literature review, only three CYP3A4 substrates showed higher Frel when formulated as CR. Several scenarios were investigated using the PBPK approach; in most of them, the oral absorption of CR formulations was lower as compared to the IR formulations. However, for highly permeable compounds that were CYP3A4 substrates the reduction in absorption was compensated by an increase in the fraction that escapes from first pass metabolism in the gut wall (FG), where the magnitude was dependent on CYP3A4 affinity. The systematic simulations of various interplays between different parameters demonstrated that BCS class 1 highly-cleared CYP3A4 substrates can display up to 220% higher relative bioavailability when formulated as CR compared to IR, in agreement with the observed data collected from the literature. The results and methodology of this study can be employed during the formulation development process in order to optimize drug absorption, especially for CYP3A4 substrates. PMID:25444842

  3. Window Observational Research Facility (WORF)

    NASA Technical Reports Server (NTRS)

    Pelfrey, Joseph; Sledd, Annette

    2007-01-01

    This viewgraph document concerns the Window Observational Research Facility (WORF) Rack, a unique facility designed for use with the US Lab Destiny Module window. WORF will provide valuable resources for Earth Science payloads along with serving the purpose of protecting the lab window. The facility can be used for remote sensing instrumentation test and validation in a shirt sleeve environment. WORF will also provide a training platform for crewmembers to do orbital observations of other planetary bodies. WORF payloads will be able to conduct terrestrial studies utilizing the data collected from utilizing WORF and the lab window.

  4. Subject Responses to Electrochromic Windows

    SciTech Connect

    Clear, Robert; Inkarojrit, Vorapat; Lee, Eleanor

    2006-03-03

    Forty-three subjects worked in a private office with switchable electrochromic windows, manually-operated Venetian blinds, and dimmable fluorescent lights. The electrochromic window had a visible transmittance range of approximately 3-60%. Analysis of subject responses and physical data collected during the work sessions showed that the electrochromic windows reduced the incidence of glare compared to working under a fixed transmittance (60%) condition. Subjects used the Venetian blinds less often and preferred the variable transmittance condition, but used slightly more electric lighting with it than they did when window transmittance was fixed.

  5. Ecophysiological function of leaf 'windows' in Lithops species - 'Living Stones' that grow underground.

    PubMed

    Martin, C E; Brandmeyer, E A; Ross, R D

    2013-01-01

    Leaf temperatures were lower when light entry at the leaf tip window was prevented through covering the window with reflective tape, relative to leaf temperatures of plants with leaf tip windows covered with transparent tape. This was true when leaf temperatures were measured with an infrared thermometer, but not with a fine-wire thermocouple. Leaf tip windows of Lithops growing in high-rainfall regions of southern Africa were larger than the windows of plants (numerous individuals of 17 species) growing in areas with less rainfall and, thus, more annual insolation. The results of this study indicate that leaf tip windows of desert plants with an underground growth habit can allow entry of supra-optimal levels of radiant energy, thus most likely inhibiting photosynthetic activity. Consequently, the size of the leaf tip windows correlates inversely with habitat solar irradiance, minimising the probability of photoinhibition, while maximising the absorption of irradiance in cloudy, high-rainfall regions. PMID:23043320

  6. INTERIOR DETAIL, RETRACTABLE WINDOW SHUTTERS, VENETIAN WINDOW IN THE SOUTHEAST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR DETAIL, RETRACTABLE WINDOW SHUTTERS, VENETIAN WINDOW IN THE SOUTHEAST CABINET. (NOTE THE MIRRORED PANEL IN THE FORWARD SHUTTER’S LOWER SECTION. DURING THE HAMILTONIAN OCCUPANCY, MIRRORS LIKE THESE WERE USED LIBERALLY THROUGHOUT THE HOUSE’S PUBLIC ROOMS - The Woodlands, 4000 Woodlands Avenue, Philadelphia, Philadelphia County, PA

  7. Use of Modeling and Simulation Tools for Understanding the Impact of Formulation on the Absorption of a Low Solubility Compound: Ciprofloxacin.

    PubMed

    Martinez, Marilyn; Mistry, Bipin; Lukacova, Viera; Polli, Jim; Hoag, Stephen; Dowling, Thomas; Kona, Ravikanth; Fahmy, Raafat

    2016-07-01

    This study explored the utility of mechanistic absorption models to describe the in vivo performance of a low solubility/low permeability compound in normal healthy subjects. Sixteen healthy human volunteers received three oral formulations and an intravenous infusion in a randomized crossover design. Plasma ciprofloxacin concentrations were estimated by HPLC. In vitro ciprofloxacin release from the oral tablets was tested under a variety of conditions. A mechanistic model was used to explore in vivo dissolution and intestinal absorption. Although dissolution rate influenced the location of drug release, absorption challenges appeared to be associated with permeability limitations in the lower small intestine and colon. The apparent relationship between drug solubilization within the upper small intestinal and formulation overall bioavailability suggested the presence of an intestinal absorption window in many individuals. Failure to absorb drug within this window appeared to be linked with the likelihood of in vivo drug precipitation. Challenges encountered during this modeling exercise included large intersubject variability in product in vivo dissolution and the apparent limitations in ciprofloxacin absorption. Although transporter activity was not included as a model parameter, this evaluation demonstrated how identifying the location of drug absorption across several formulations provided an opportunity to identify factors to consider when formulating similar low solubility/low permeability compounds. The use of mechanistic models was invaluable for our understanding of in vivo product performance and for the assessment of individual profiles rather than means. The latter was essential for understanding the potential challenges that may be encountered when introducing a formulation into a patient population. PMID:27116024

  8. Destiny's Earth Observation Window

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Astronaut Michael J. Bloomfield, STS-110 mission commander, looks through the Earth observation window in the Destiny laboratory aboard the International Space Station (ISS). The STS-110 mission prepared the ISS for future spacewalks by installing and outfitting the S0 (S-zero) truss and the Mobile Transporter. The 43-foot-long S0 Truss, weighing in at 27,000 pounds, was the first of 9 segments that will make up the Station's external framework that will eventually stretch 356 feet (109 meters), or approximately the length of a football field. This central truss segment also includes a flatcar called the Mobile Transporter and rails that will become the first 'space railroad,' which will allow the Station's robotic arm to travel up and down the finished truss for future assembly and maintenance. The completed truss structure will hold solar arrays and radiators to provide power and cooling for additional international research laboratories from Japan and Europe that will be attached to the Station. Milestones of the STS-110 mission included the first time the ISS robotic arm was used to maneuver spacewalkers around the Station and marked the first time all spacewalks were based out of the Station's Quest Airlock. It was also the first Shuttle to use three Block II Main Engines. The Space Shuttle Orbiter Atlantis, STS-110 mission, was launched April 8, 2002 and returned to Earth April 19, 2002.

  9. Prism Window for Optical Alignment

    NASA Technical Reports Server (NTRS)

    Tang, Hong

    2008-01-01

    A prism window has been devised for use, with an autocollimator, in aligning optical components that are (1) required to be oriented parallel to each other and/or at a specified angle of incidence with respect to a common optical path and (2) mounted at different positions along the common optical path. The prism window can also be used to align a single optical component at a specified angle of incidence. Prism windows could be generally useful for orienting optical components in manufacture of optical instruments. "Prism window" denotes an application-specific unit comprising two beam-splitter windows that are bonded together at an angle chosen to obtain the specified angle of incidence.

  10. A modified emulsion gelation technique to improve buoyancy of hydrogel tablets for floating drug delivery systems.

    PubMed

    Yom-Tov, Ortal; Seliktar, Dror; Bianco-Peled, Havazelet

    2015-10-01

    The use of buoyant or floating hydrogel tablets is of particular interest in the sustained release of drugs to the stomach. They have an ability to slow the release rates of drugs by prolonging their absorption window in the upper part of the gastrointestinal (GI) tract. In this study we synthesized bioactive hydrogels that have sustainable release rates for drugs in the stomach based on a hydrogel preparation technique that employs emulsifying surfactants. The emulsion gelation technique, which encapsulates oil droplets within the hydrogels during crosslinking, was used to decrease their specific gravity in aqueous environments, resulting in floating drug release depots. Properties such as swelling, buoyancy, density and drug release were manipulated by changing the polymer concentrations, surfactant percentages and the oil:polymer ratios. The relationship between these properties and the hydrogel's floating lag time was documented. The potential for this material to be used as a floating drug delivery system was demonstrated. PMID:26117764

  11. Deep optical imaging of tissue using the second and third near-infrared spectral windows

    NASA Astrophysics Data System (ADS)

    Sordillo, Laura A.; Pu, Yang; Pratavieira, Sebastião; Budansky, Yury; Alfano, Robert R.

    2014-05-01

    Light at wavelengths in the near-infrared (NIR) region allows for deep penetration and minimal absorption through high scattering tissue media. NIR light has been conventionally used through the first NIR optical tissue window with wavelengths from 650 to 950 nm. Longer NIR wavelengths had been overlooked due to major water absorption peaks and a lack of NIR-CCD detectors. The second NIR spectral window from 1100 to 1350 nm and a new spectral window from 1600 to 1870 nm, known as the third NIR optical window, were investigated. Optical attenuation measurements from thin tissue slices of normal and malignant breast and prostate tissues, pig brain, and chicken tissue were obtained in the spectral range from 400 to 2500 nm. Optical images of chicken tissue overlying three black wires were also obtained using the second and third spectral windows. Due to a reduction in scattering and minimal absorption, longer attenuation lengths and clearer optical images could be seen in the second and third NIR optical windows compared to the conventional first NIR optical window. A possible fourth optical window centered at 2200 nm was noted.

  12. Subgap Absorption in Conjugated Polymers

    DOE R&D Accomplishments Database

    Sinclair, M.; Seager, C. H.; McBranch, D.; Heeger, A. J; Baker, G. L.

    1991-01-01

    Along with X{sup (3)}, the magnitude of the optical absorption in the transparent window below the principal absorption edge is an important parameter which will ultimately determine the utility of conjugated polymers in active integrated optical devices. With an absorptance sensitivity of < 10{sup {minus}5}, Photothermal Deflection Spectroscopy (PDS) is ideal for determining the absorption coefficients of thin films of transparent'' materials. We have used PDS to measure the optical absorption spectra of the conjugated polymers poly(1,4-phenylene-vinylene) (and derivitives) and polydiacetylene-4BCMU in the spectral region from 0.55 eV to 3 eV. Our spectra show that the shape of the absorption edge varies considerably from polymer to polymer, with polydiacetylene-4BCMU having the steepest absorption edge. The minimum absorption coefficients measured varied somewhat with sample age and quality, but were typically in the range 1 cm{sup {minus}1} to 10 cm{sup {minus}1}. In the region below 1 eV, overtones of C-H stretching modes were observed, indicating that further improvements in transparency in this spectral region might be achieved via deuteration of fluorination.

  13. Tokamak physics experiment: Diagnostic windows study

    SciTech Connect

    Merrigan, M.; Wurden, G.A.

    1995-11-01

    We detail the study of diagnostic windows and window thermal stress remediation in the long-pulse, high-power Tokamak Physics Experiment (TPX) operation. The operating environment of the TPX diagnostic windows is reviewed, thermal loads on the windows estimated, and cooling requirements for the windows considered. Applicable window-cooling technology from other fields is reviewed and its application to the TPX windows considered. Methods for TPX window thermal conditioning are recommended, with some discussion of potential implementation problems provided. Recommendations for further research and development work to ensure performance of windows in the TPX system are presented.

  14. Holography through optically active windows

    NASA Technical Reports Server (NTRS)

    Decker, A. J.

    1979-01-01

    By using two orthogonally polarized reference beams, holograms can be recorded through stressed windows and the reconstructed virtual image will show no stress pattern. As shown analytically, the stress-pattern-free hologram is recordable for any polarization state of the object illumination. Hence, the more efficient nondepolarizing diffuser can be used in performing holography through stressed windows if two reference beams are used. Results are presented for a pair of machined polysulfone windows intended for use in a holographic flow-visualization setup in a single-stage-compressor test rig.

  15. Window Design for Manned Spaceflight

    NASA Astrophysics Data System (ADS)

    Lamoure, Richard; Kitchingman, Ian; Novo, Francisco; Sinnema, Gerben

    2012-07-01

    The Window Design for Manned Spacecraft (WDM) project being undertaken by Magna Parva Ltd, under contract with the European Space Agency, aims to develop and improve the current structural integrity verification program for manned spacecraft pressurised windows. A critical review of the existing requirements and current state-of-the-art in spacecraft window design, materials and verification practice is conducted. Possible areas for improvement are identified. An experimental test programme is designed to perform and assess mechanical characterisation methods at material level. Tests are intended to increase familiarity with material testing methods and investigate the effects of sample size, surface finish and load type on material characterisation. Novel methods and their applicability are investigated. Results of characterisation testing will be employed in the design and verification of a breadboard window.

  16. Window-closing safety system

    DOEpatents

    McEwan, T.E.

    1997-08-26

    A safety device includes a wire loop embedded in the glass of a passenger car window and routed near the closing leading-edge of the window. The wire loop carries microwave pulses around the loop to and from a transceiver with separate output and input ports. An evanescent field only an inch or two in radius is created along the wire loop by the pulses. Just about any object coming within the evanescent field will dramatically reduce the energy of the microwave pulses received back by the transceiver. Such a loss in energy is interpreted as a closing area blockage, and electrical interlocks are provided to halt or reverse a power window motor that is actively trying to close the window. 5 figs.

  17. Window-closing safety system

    DOEpatents

    McEwan, Thomas E.

    1997-01-01

    A safety device includes a wire loop embedded in the glass of a passenger car window and routed near the closing leading-edge of the window. The wire loop carries microwave pulses around the loop to and from a transceiver with separate output and input ports. An evanescent field only and inch or two in radius is created along the wire loop by the pulses. Just about any object coming within the evanescent field will dramatically reduce the energy of the microwave pulses received back by the transceiver. Such a loss in energy is interpreted as a closing area blockage, and electrical interlocks are provided to halt or reverse a power window motor that is actively trying to close the window.

  18. X-ray transmission through a plasma window

    NASA Astrophysics Data System (ADS)

    Pinkoski, B. T.; Zacharia, I.; Hershcovitch, A.; Johnson, E. D.; Siddons, D. P.

    2001-03-01

    Traditional solid window materials used for x-ray synchrotron beamlines may introduce undesirably high attenuation, or are subject to failure under high heat loads. A plasma window can in principle obviate these problems over a wide range of energies. Experiments were performed at the Brookhaven National Laboratory National Synchrotron Light Source on beamline X6A to study the transmission characteristics of a plasma window using argon as the arc gas. Measurements were made around the Ar K edge and far from resonance. The "white-line" absorption at the K edge was actually suppressed during arc operation as compared to room temperature gas at the same pressure. This is attributed to the high degree of ionization in the plasma. The relative strength of the white line to the edge jump does not seem to be a strong function of arc current at the argon K edge. Away from resonance (˜3 times the edge energy) x-ray attenuation was negligible.

  19. A window on urban sustainability

    SciTech Connect

    Stigt, Rien van; Driessen, Peter P.J.; Spit, Tejo J.M.

    2013-09-15

    Sustainable urban development requires the integration of environmental interests in urban planning. Although various methods of environmental assessment have been developed, plan outcomes are often disappointing due to the complex nature of decision-making in urban planning, which takes place in multiple arenas within multiple policy networks involving diverse stakeholders. We argue that the concept of ‘decision windows’ can structure this seemingly chaotic chain of interrelated decisions. First, explicitly considering the dynamics of the decision-making process, we further conceptualized decision windows as moments in an intricate web of substantively connected deliberative processes where issues are reframed within a decision-making arena, and interests may be linked within and across arenas. Adopting this perspective in two case studies, we then explored how decision windows arise, which factors determine their effectiveness and how their occurrence can be influenced so as to arrive at more sustainable solutions. We conclude that the integration of environmental interests in urban planning is highly dependent on the ability of the professionals involved to recognize and manipulate decision windows. Finally, we explore how decision windows may be opened. -- Highlights: • Decision-making about sustainable urban development occurs in networks. • The concept of ‘decision windows’ was further elaborated. • Decision windows help understand how environmental interests enter decision-making. • Decision windows can, to some extent, be influenced.

  20. Effect of particle size reduction on dissolution and oral absorption of a poorly water-soluble drug, cilostazol, in beagle dogs.

    PubMed

    Jinno, Jun-ichi; Kamada, Naoki; Miyake, Masateru; Yamada, Keigo; Mukai, Tadashi; Odomi, Masaaki; Toguchi, Hajime; Liversidge, Gary G; Higaki, Kazutaka; Kimura, Toshikiro

    2006-03-10

    The purpose of the present study was to investigate the effects of particle size on the dissolution and oral absorption of cilostazol. Three types of suspensions having different particle size distributions were prepared of the hammer-milled, the jet-milled cilostazol crystals and the NanoCrystal spray-dried powder of cilostazol. In vitro dissolution rate of cilostazol was significantly increased by reducing the particle size. The dissolution curves of the cilostazol suspensions were in good agreement with the simulation based on the Noyes-Whitney equation. The bioavailability of cilostazol after oral administration to dogs was increased with reducing the particle size. While positive food effect on the absorption was observed for the suspensions made of the hammer-milled and the jet-milled crystals, no significant food effect was found for the suspension made of the NanoCrystal cilostazol spray-dried powder. These results could be qualitatively predicted from the in vitro dissolution data using the bio-relevant media, FaSSIF and FeSSIF. In conclusion, the NanoCrystal technology is found to be efficient to improve the oral bioavailability of cilostazol and to avoid the food effect on the absorption. PMID:16410029

  1. Gut Wall Metabolism. Application of Pre-Clinical Models for the Prediction of Human Drug Absorption and First-Pass Elimination.

    PubMed

    Jones, Christopher R; Hatley, Oliver J D; Ungell, Anna-Lena; Hilgendorf, Constanze; Peters, Sheila Annie; Rostami-Hodjegan, Amin

    2016-05-01

    Quantifying the multiple processes which control and modulate the extent of oral bioavailability for drug candidates is critical to accurate projection of human pharmacokinetics (PK). Understanding how gut wall metabolism and hepatic elimination factor into first-pass clearance of drugs has improved enormously. Typically, the cytochrome P450s, uridine 5'-diphosphate-glucuronosyltransferases and sulfotransferases, are the main enzyme classes responsible for drug metabolism. Knowledge of the isoforms functionally expressed within organs of first-pass clearance, their anatomical topology (e.g. zonal distribution), protein homology and relative abundances and how these differ across species is important for building models of human metabolic extraction. The focus of this manuscript is to explore the parameters influencing bioavailability and to consider how well these are predicted in human from animal models or from in vitro to in vivo extrapolation. A unique retrospective analysis of three AstraZeneca molecules progressed to first in human PK studies is used to highlight the impact that species differences in gut wall metabolism can have on predicted human PK. Compared to the liver, pharmaceutical research has further to go in terms of adopting a common approach for characterisation and quantitative prediction of intestinal metabolism. A broad strategy is needed to integrate assessment of intestinal metabolism in the context of typical DMPK activities ongoing within drug discovery programmes up until candidate drug nomination. PMID:26964996

  2. Cholesterol Absorption and Metabolism.

    PubMed

    Howles, Philip N

    2016-01-01

    Inhibitors of cholesterol absorption have been sought for decades as a means to treat and prevent cardiovascular diseases (CVDs) associated with hypercholesterolemia. Ezetimibe is the one clear success story in this regard, and other compounds with similar efficacy continue to be sought. In the last decade, the laboratory mouse, with all its genetic power, has become the premier experimental model for discovering the mechanisms underlying cholesterol absorption and has become a critical tool for preclinical testing of potential pharmaceutical entities. This chapter briefly reviews the history of cholesterol absorption research and the various gene candidates that have come under consideration as drug targets. The most common and versatile method of measuring cholesterol absorption is described in detail along with important considerations when interpreting results, and an alternative method is also presented. In recent years, reverse cholesterol transport (RCT) has become an area of intense new interest for drug discovery since this process is now considered another key to reducing CVD risk. The ultimate measure of RCT is sterol excretion and a detailed description is given for measuring neutral and acidic fecal sterols and interpreting the results. PMID:27150091

  3. Silicon as an advanced window material for high power gyrotrons

    SciTech Connect

    Parshin, V.V.; Andreev, B.A.; Gusev, A.V.

    1995-05-01

    The absorptivity of high-purity grades of silicon (Si) and its reduction by subsequent doping procedures are investigated. The dielectric data are given for the wide range of frequencies (30 -330 GHz) and temperatures (30 -330 K) in comparison with the data set for sapphire. The advanced material performance in high power window applications is discussed taking into account both dielectric properties of the optimized silicon grades and thermal conductivity.

  4. Spectral selectivity of electrochromic windows with color state for all-sky conditions

    SciTech Connect

    Soule, D.E.; Zhang, J.G.; Benson, D.K.

    1995-07-01

    The optical performance of an electrochromic window is studied for the visible, ultraviolet, and near infrared spectral regions. The performance is found to deviate strongly with window color state and for clear or cloudy skies. A new spectral cloud model is applied to an electrochromic window recently developed at NREL. A spectral comparison is made between the electrochromic window and spectrally selective standard windows. Two series of double-glazed window sections, including the electrochromic window with color state and a series of low-E windows, were measured for transmittance and reflectance (300-2500nm), With these spectral data, a new near-infrared blocking (reflection + absorption) factor is developed for window application in warm climates for cooling load reduction. A chromaticity analysis is presented for both the daylight spectra and the transmitted electrochromic window spectra with color state, Computed daylight correlated color temperatures show a wide range, with values of 5660K for clear global irradiation, 6210K for clouds, and 13,250K for a zenith blue sky. Chromatic trajectories with color state for transmitted radiation extend further toward the blue to 8180K for the global and 28,990K for zenith sky irradiation.

  5. Window decompression in laser-heated MagLIF targets

    NASA Astrophysics Data System (ADS)

    Woodbury, Daniel; Peterson, Kyle; Sefkow, Adam

    2015-11-01

    The Magnetized Liner Inertial Fusion (MagLIF) concept requires pre-magnetized fuel to be pre-heated with a laser before undergoing compression by a thick solid liner. Recent experiments and simulations suggest that yield has been limited to date by poor laser preheat and laser-induced mix in the fuel region. In order to assess laser energy transmission through the pressure-holding window, as well as resultant mix, we modeled window disassembly under different conditions using 1D and 2D simulations in both Helios and HYDRA. We present results tracking energy absorption, time needed for decompression, risk of laser-plasma interaction (LPI) that may scatter laser light, and potential for mix from various window thicknesses, laser spot sizes and gas fill densities. These results indicate that using thinner windows (0.5-1 μm windows) and relatively large laser spot radii (600 μm and above) can avoid deleterious effects and improve coupling with the fuel. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the National Nuclear Security Administration under DE-AC04- 94AL85000.

  6. Gastroretentive drug delivery of metformin hydrochloride: formulation and in vitro evaluation using 3(2) full factorial design.

    PubMed

    Boldhane, Sanjay P; Kuchekar, Bhanudas S

    2009-10-01

    Metformin Hydrochloride (MF) is glucose lowering agent that is widely used for management for type II diabetes. MF is reported to be absorbed mainly in upper part of GIT. It is having narrow absorption window and high water solubility, and it would be more beneficial to retain the drug in stomach for prolonged duration so as to achieve maximum absorption and better bioavailability. A conventional oral CR formulation releases most of the drug content at the colon, which requires that the drug will be absorbed from the colon. The present investigation is aimed to develop novel gastroretentive (GR) drug delivery system, which not only release the drug in the absorption window but also provides controlled release drug profile that may result patient compliance and therapeutic success. Floating tablets of MF was prepared using sodium alginate, and sodium carboxymethylcellulose was used as a gelling agent, and release modifiers, respectively. Eudragit NE 30 D was used as sustained release polymer to control the initial burst release. Drug and excipients compatibility studies were monitored by thermal analysis by using differential scanning calorimeter. 32 full factorial design was applied to optimize the formulation. The DSC thermogram of drug, polymer and physical mixtures revealed that there was no known interaction between drug and polymers. The prepared tablets were evaluated for in vitro dissolution, in vitro buoyancy, percentage swelling, percentage erosion and similarity factors with marketed tablets. The optimization study using a 32 full factorial design revealed that the amount of sodium alginate and sodium carboxymethylcellulose had a significant effect on t50, t90, Flag and f2. Thus, by selecting a suitable composition of release rate modifier and gel forming agent, Gastro retentive system can be developed with the desired dissolution profile. This study indicated that the MF GR tablets prepared using sodium alginate and sodium carboxymethylcellulose can

  7. Extending the X Window System

    SciTech Connect

    Brenkosh, J.P.

    1993-12-23

    The X Window System was originally developed in 1984 at Massachusetts Institute of Technology. It provides client-server computing functionality and also facilitates the establishment of a distributed computing environment. Since its inception the X Window System has undergone many enhancements. Despite these enhancements there will always be a functionality desired in the standard released version of X that is not supported or commercially or academically available. The developers of the X Window System have designed it in such a way that it is possible to add functionality that is not included in the standard release. This is called an extension. Extensions are one method used to develop a customized version of the X Window System to support a specialized application. This report presents the mechanics of adding an extension and examines a particular extension that was developed at Sandia National Laboratories to support data compression in X Windows which was one aspect of the Desktop Video and Collaborative Engineering Laboratory Directed Research and Development (LDRD).

  8. Switchable Materials for Smart Windows.

    PubMed

    Wang, Yang; Runnerstrom, Evan L; Milliron, Delia J

    2016-06-01

    This article reviews the basic principles of and recent developments in electrochromic, photochromic, and thermochromic materials for applications in smart windows. Compared with current static windows, smart windows can dynamically modulate the transmittance of solar irradiation based on weather conditions and personal preferences, thus simultaneously improving building energy efficiency and indoor human comfort. Although some smart windows are commercially available, their widespread implementation has not yet been realized. Recent advances in nanostructured materials provide new opportunities for next-generation smart window technology owing to their unique structure-property relations. Nanomaterials can provide enhanced coloration efficiency, faster switching kinetics, and longer lifetime. In addition, their compatibility with solution processing enables low-cost and high-throughput fabrication. This review also discusses the importance of dual-band modulation of visible and near-infrared (NIR) light, as nearly 50% of solar energy lies in the NIR region. Some latest results show that solution-processable nanostructured systems can selectively modulate the NIR light without affecting the visible transmittance, thus reducing energy consumption by air conditioning, heating, and artificial lighting. PMID:27023660

  9. 16 CFR 455.3 - Window form.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Window form. 455.3 Section 455.3 Commercial... Window form. (a) Form given to buyer. Give the buyer of a used vehicle sold by you the window form...) Incorporated into contract. The information on the final version of the window form is incorporated into...

  10. Windows and daylighting: A brighter outlook

    SciTech Connect

    Not Available

    1994-11-01

    This is an overview of energy efficient window glazing and framing technology. The topics of the report include: windows and energy use, a point of view; a challenging federal opportunity; DOE window research; advanced optical technologies such as spectrally selective glazing, switchable glazing, super windows with low-emissivity coatings and noble gas fills; and performance evaluation and design tools.

  11. A robust industrial accelerator window design

    NASA Astrophysics Data System (ADS)

    Schuetz, Marlin N.; Vroom, David A.

    1998-06-01

    An improved design for the thin metal foil window associated with high power industrial accelarators has been developed and tested. This design, which employs specifically shaped flanges, greatly reduce the stresses normally present on accelerators windows and has lead to longer window lifetime and a better means of window cooling.

  12. Music@Microsoft.Windows: Composing Ambience

    ERIC Educational Resources Information Center

    Rickert, Thomas

    2010-01-01

    It is well known, of course, that all Windows versions except for 3.1 have a brief (four to six second) piece of music indicating that Windows is booted and ready for use. While the music may indicate Windows has booted, it bears no immediately discernable relation to the various uses we might actually put Windows to--working, gaming,…

  13. Investigation of failure mechanisms in high-power microwave transmission windows

    NASA Astrophysics Data System (ADS)

    Bosman, Herman L.

    Thermal runaway and window failure restrict the power output of high power (˜1 MW), long pulse length (˜10 sec) gyrotrons used for plasma heating in magnetic confinement fusion experiments. Chemical vapor deposition diamond is used as window material due to its low loss tangent and high thermal conductivity, but still suffers from occasional, unpredictable failure. With the use of a simple model, it is shown that a uniform thin film of contaminant on a microwave window may absorb up to 50 percent of the incident power, even if the film thickness is only a small fraction of its resistive skin depth. The fraction of power absorbed by thin films on diamond gyrotron windows is estimated by comparison with published data obtained via two different experimental routes. Typically about a fraction of one percent of the incident power is absorbed by the thin films. Discontinuous surface films, where the surface contaminants have a patchy or island structure, are modeled with an equivalent transmission line circuit. Patchy surface contaminants on diamond gyrotron windows do not contribute significantly to the overall power absorbed on the window surface. An unexpected result is that most of the power is absorbed on the 'clean' window surface. The uniform thin film model is therefore adequate to describe surface power losses for diamond windows. The discontinuous film model, applied to alumina windows with TIN coatings, shows power absorption values of approximately 0.1--0.3%. Graphitic contaminants embedded in the CVD diamond absorb RE power from both the RE electric and magnetic field components. The absorbed power is insufficient to cause significant heating or cause graphitization in the diamond. The power absorbed in a diamond gyrotron window causes thermal gradient stresses in the window, with the maximum tensile stress occurring close to the window edge. For power absorption values up to 2000 W, the tensile stresses alone are insufficient to cause mechanical failure

  14. Enhanced rectal absorption and reduced local irritation of the anti-inflammatory drug ethyl 4-biphenylylacetate in rats by complexation with water-soluble beta-cyclodextrin derivatives and formulation as oleaginous suppository.

    PubMed

    Arima, H; Kondo, T; Irie, T; Uekama, K

    1992-11-01

    To improve the rectal delivery of ethyl 4-biphenylylacetate (EBA), a prodrug of the anti-inflammatory drug 4-biphenylylacetic acid (BPAA), the use of highly water-soluble 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CyD) and heptakis(2,6-di-O-methyl)-beta-cyclodextrin (DM-beta-CyD) was investigated and compared with the use of the parent beta-cyclodextrin (beta-CyD). Among the three beta-CyDs, HP-beta-CyD was best at improving the rectal bioavailability of EBA in rats after single and multiple administrations of oleaginous suppositories (Witepsol H-5) containing the complexes. To gain insight into the enhancing effect of beta-CyDs, the absorption behaviors of EBA (observed by monitoring BPAA as an active metabolite of EBA) and beta-CyDs themselves were examined in vitro, in situ, and in vivo. The in situ recirculation study revealed that the complexed form of EBA was less absorbable from the rectal lumen in the solution state, but this disadvantageous effect of beta-CyDs was compensated in part by the inhibition of the bioconversion of EBA to BPAA. When beta-CyDs were coadministered with EBA in vivo, however, rather high amounts of HP-beta-CyD (approximately 26% of dose) and DM-beta-CyD (approximately 21% of dose), compared with beta-CyD (approximately 5% of dose), were absorbed from the rat rectum. Thus, the enhancement of rectal absorption of EBA in vivo can be explained by the facts that the hydrophilic beta-CyDs increased the release rate of EBA from the vehicle and stabilized EBA in the rectal lumen and that the drug was partly absorbed in the form of the complex.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1447717

  15. The Benefits of Aluminum Windows.

    ERIC Educational Resources Information Center

    Goyal, R. C.

    2002-01-01

    Discusses benefits of aluminum windows for college construction and renovation projects, including that aluminum is the most successfully recycled material, that it meets architectural glass deflection standards, that it has positive thermal energy performance, and that it is a preferred exterior surface. (EV)

  16. Creating a Window Cleaner Company.

    ERIC Educational Resources Information Center

    Sarquis, A. M.; And Others

    1995-01-01

    Provides a description of a project used in the Cool Science and Technology Camps in which campers are presented with the challenge of developing and marketing their own brand of window cleaner. Topics such as chemistry, marketing, and cost analysis are intertwined as students prepare and plan their approach to product development. (DDR)

  17. Notes on UHV beryllium windows

    SciTech Connect

    Hartman, P.L.

    1986-10-01

    Techniques are described for making large ultrahigh vacuum beryllium windows for use in synchrotron radiation installations. Procedures are given for affecting both hard brazed seals and demountable seals involving either lead or copper gaskets. Brazed seals can be made to either stainless steel or copper. Possible alternative methods are suggested.

  18. Closing the Windows on Opportunity.

    ERIC Educational Resources Information Center

    Coombs, Norman

    1995-01-01

    The rapid adoption of graphic user interface (GUI), as indicated by Microsoft's Windows95 and the Internet's increased use of graphics, is threatening information technology opportunities for people with disabilities. Recent legislation requires that schools provide access to computers and information technology, and producers of Mosaic are…

  19. Isolated attosecond soft X-rays and water window XAFS

    NASA Astrophysics Data System (ADS)

    Biegert, Jens

    2016-05-01

    We demonstrate generation of isolated attosecond soft X-ray pulses with duration less than 350 as at the carbon K-edge at 284 eV. This reproducible and CEP stable attosecond soft X-ray continuum covers the entire water window from 200 eV to 550 eV with a flux of 7.3x 107 photons/s and corresponds to a pulse energy of 2.9 pJ. We demonstrate the utility of our table-top source through soft X-ray near-edge fine-structure spectroscopy at K-shell absorption edges in condensed matter and retrieve the specific absorption features corresponding to the binding orbitals. We believe that these results herald attosecond material science by bridging the gap between ultrafast temporal resolution and element specific probing at the fundamental absorption edges of matter.

  20. Laser absorption phenomena in flowing gas devices

    NASA Technical Reports Server (NTRS)

    Chapman, P. K.; Otis, J. H.

    1976-01-01

    A theoretical and experimental investigation is presented of inverse Bremsstrahlung absorption of CW CO2 laser radiation in flowing gases seeded with alkali metals. In order to motivate this development, some simple models are described of several space missions which could use laser powered rocket vehicles. Design considerations are given for a test call to be used with a welding laser, using a diamond window for admission of laser radiation at power levels in excess of 10 kW. A detailed analysis of absorption conditions in the test cell is included. The experimental apparatus and test setup are described and the results of experiments presented. Injection of alkali seedant and steady state absorption of the laser radiation were successfully demonstrated, but problems with the durability of the diamond windows at higher powers prevented operation of the test cell as an effective laser powered thruster.

  1. Study on optimizing the thickness of silicon window of WLP for IR sensor

    NASA Astrophysics Data System (ADS)

    Song, Myeongho; Kim, Tae Hyun; Hyun, Moon Seop; Park, Jae Hong; Kim, Hee Yeoun; Lee, Gawon

    2012-06-01

    Silicon is a promising material as an IR(Infrared Ray) transparent window platform for packaging MEMS( microelectro mechanical systems), especially, IR sensors with WLP(wafer level package), because silicon has advantages in price and CMOS process compatibility compared to Ge, although Ge exhibits higher IR transmittance than Si. This paper reports on optimizing the thickness of Si window in the range of 8 ~ 12 um, LW-IR(Long wave IR). Two of important things which have to be considered in window material of IR sensor are minimizing absorption of IR(maximizing transmittance) and minimizing deformation due to the pressure differences between outside and inside of the package. Because of trade-off between minimizing IR absorption and minimizing mechanical deformation, optimization of thickness is important. Infrared absorbance of silicon was measured as varying thickness from 100 um to 700 um of the Si window. Decreasing the thickness of silicon made the absorption smaller. Under 300 um, the difference of absorbance with decreasing thickness becomes negligible. Degree of deformation according to the thickness of the Si window was calculated by simulation varying pressure differences, and package area. Based on this analysis, we suggest the optimized thickness of silicon window for WLP of LW-IR sensor.

  2. Effect of added alkalizer and surfactant on dissolution and absorption of the potassium salt of a weakly basic poorly water-soluble drug.

    PubMed

    Mahjour, Majid; Kesisoglou, Filippos; Cruanes, Maria; Xu, Wei; Zhang, Dina; Maguire, Timothy J; Rosen, Lawrence A; Templeton, Allen C; Kress, Michael H

    2014-06-01

    Telcagepant potassium salt (MK-0974) is an oral calcitonin gene-related peptide receptor inhibitor investigated for the treatment of acute migraine. Under gastric pH conditions, the salt rapidly gels, then converts to an insoluble neutral form that creates an impervious shell on the tablet surface, resulting in a slow and variable release dissolution rate and poor bioavailability. Early attempts to develop a solid dosage form, including solid dispersion and nanosuspension formulations, resulted in low exposures in preclinical studies. Thus, a liquid-filled soft gelatin capsule (SGC) formulation (oblong 20) was used for clinical studies. However, a solid dosage form was desirable for commercialization. The slow dissolution of the tablet formulations was overcome by using a basifying agent, arginine, and inclusion of a nonionic surfactant, poloxamer 407. The combination of arginine and poloxamer in the formulation created a local transient basic microenvironment that promoted the dissolution of the salt and prevented rapid precipitation of the neutral form on the tablet surface to form the gel layer. The tablet formulation achieved fast absorption and comparable exposure to the SGC formulation. The final optimized 280 mg tablet formulation was successfully demonstrated to be bioequivalent to the 300 mg SGC formulation. PMID:24788413

  3. Drug absorption in vitro model: filter-immobilized artificial membranes. 2. Studies of the permeability properties of lactones in Piper methysticum Forst.

    PubMed

    Avdeef, A; Strafford, M; Block, E; Balogh, M P; Chambliss, W; Khan, I

    2001-12-01

    The assessment of transport properties of 23 drug and natural product molecules was made using the in vitro model based on filter-immobilized artificial membranes (filter-IAM), assembled from phosphatidylcholine in dodecane, in buffer solutions at pH 7.4. Five of the compounds were lactones extracted from the roots of the kava-kava plant. Experiments were designed to test the effects of stirring (0-600 rpm) during assays and the effects of varying the assay times (2-15 h). The highly mobile kava lactones permeated in the order dihydromethisticin (40)>yangonin (37)>kavain (34)>methisticin (32)>desmethoxyyangonin (26), the numbers in parentheses being the measured effective permeabilities in units of 10(-6) cm/s. By comparison, commercial drugs ranked: phenazopyridine (35)>testosterone (19)>propranolol (13)>ketoconazole (6.3)>piroxicam (2.2)>caffeine (1.7)>metoprolol (0.8)>terbutaline (0.01). In addition to permeability measurements, membrane retention of compounds was determined. Yangonin, desmethoxyyangonin, ketoconazole, and phenazopyridine were more than 60% retained by the artificial membranes containing phospholipids. Stirring during assay significantly increased the observed permeabilities for highly mobile molecules, but had minimal impact on the poorly permeable molecules. The influence of hydrogen bonding was explored by determining permeabilities using filters coated with dodecane free of phospholipids. In the filter-IAM method, concentrations were determined by microtitre plate UV spectrophotometry and by LC-MS. Higher-throughput was achieved with direct UV by the use of 96-well microtitre plate formats and with LC-MS by the use of cassette dosing (five-in-one). PMID:11684401

  4. Removable Window System for Space Vehicles

    NASA Technical Reports Server (NTRS)

    Grady, James P. (Inventor)

    2015-01-01

    A window system for a platform comprising a window pane, a retention frame, and a biasing system. The window pane may be configured to contact a sealing system. The retention frame may be configured to contact the sealing system and hold the window pane against the support frame. The biasing system may be configured to bias the retention frame toward the support frame while the support frame and the retention frame are in a configuration that holds the window pane. Removal of the biasing system may cause the retention frame and the window pane to be removable.

  5. Measured winter performance of storm windows

    SciTech Connect

    Klems, Joseph H.

    2002-08-23

    Direct comparison measurements were made between various prime/storm window combinations and a well-weatherstripped, single-hung replacement window with a low-E selective glazing. Measurements were made using an accurate outdoor calorimetric facility with the windows facing north. The doublehung prime window was made intentionally leaky. Nevertheless, heat flows due to air infiltration were found to be small, and performance of the prime/storm combinations was approximately what would be expected from calculations that neglect air infiltration. Prime/low-E storm window combinations performed very similarly to the replacement window. Interestingly, solar heat gain was not negligible, even in north-facing orientation.

  6. High-efficiency nanostructured window GaAs solar cells.

    PubMed

    Liang, Dong; Kang, Yangsen; Huo, Yijie; Chen, Yusi; Cui, Yi; Harris, James S

    2013-10-01

    Nanostructures have been widely used in solar cells due to their extraordinary optical properties. In most nanostructured cells, high short circuit current has been obtained due to enhanced light absorption. However, most of them suffer from lowered open circuit voltage and fill factor. One of the main challenges is formation of good junction and electrical contact. In particular, nanostructures in GaAs only have shown unsatisfactory performances (below 5% in energy conversion efficiency) which cannot match their ideal material properties and the record photovoltaic performances in industry. Here we demonstrate a completely new design for nanostructured solar cells that combines nanostructured window layer, metal mesa bar contact with small area, high quality planar junction. In this way, we not only keep the advanced optical properties of nanostructures such as broadband and wide angle antireflection, but also minimize its negative impact on electrical properties. High light absorption, efficient carrier collection, leakage elimination, and good lateral conductance can be simultaneously obtained. A nanostructured window cell using GaAs junction and AlGaAs nanocone window demonstrates 17% energy conversion efficiency and 0.982 V high open circuit voltage. PMID:24021024

  7. Windows in the Milky Way

    NASA Technical Reports Server (NTRS)

    Waller, William H.; Tacconi-Garman, Lowell Evan; Boulanger, Francois; Okumura, Koryo

    1991-01-01

    The objectives were twofold: (1) to study the IRAS emission levels in the vicinity of Baade's Window and in other optically transparent regions near the Galactic Center; and (2) to study the IRAS emission levels along sightlines in the Milky Way that exhibit very little CO emission. Tests were attempted to see whether the optically transparent 'windows' near the Galactic center can be identified (as FIR-weak regions) in the IRAS data base; and if so, whether the CO weak regions found elsewhere in the Milky Way represent similarly FIR weak and thus optically transparent sightlines through the Galaxy. The CO weak regions were also targeted in an effort to study the diffuse intercloud dust and its warming by the interstellar radiation field.

  8. Electrochromic Windows: Advanced Processing Technology

    SciTech Connect

    SAGE Electrochromics, Inc

    2006-12-13

    This project addresses the development of advanced fabrication capabilities for energy saving electrochromic (EC) windows. SAGE EC windows consist of an inorganic stack of thin films deposited onto a glass substrate. The window tint can be reversibly changed by the application of a low power dc voltage. This property can be used to modulate the amount of light and heat entering buildings (or vehicles) through the glazings. By judicious management of this so-called solar heat gain, it is possible to derive significant energy savings due to reductions in heating lighting, and air conditioning (HVAC). Several areas of SAGE’s production were targeted during this project to allow significant improvements to processing throughput, yield and overall quality of the processing, in an effort to reduce the cost and thereby improve the market penetration. First, the overall thin film process was optimized to allow a more robust set of operating points to be used, thereby maximizing the yield due to the thin film deposition themselves. Other significant efforts aimed at improving yield were relating to implementing new procedures and processes for the manufacturing process, to improve the quality of the substrate preparation, and the quality of the IGU fabrication. Furthermore, methods for reworking defective devices were developed, to enable devices which would otherwise be scrapped to be made into useful product. This involved the in-house development of some customized equipment. Finally, the improvements made during this project were validated to ensure that they did not impact the exceptional durability of the SageGlass® products. Given conservative estimates for cost and market penetration, energy savings due to EC windows in residences in the US are calculated to be of the order 0.026 quad (0.026×1015BTU/yr) by the year 2017.

  9. Consensus guidelines for optimising antifungal drug delivery and monitoring to avoid toxicity and improve outcomes in patients with haematological malignancy, 2014.

    PubMed

    Chau, M M; Kong, D C M; van Hal, S J; Urbancic, K; Trubiano, J A; Cassumbhoy, M; Wilkes, J; Cooper, C M; Roberts, J A; Marriott, D J E; Worth, L J

    2014-12-01

    Antifungal agents may be associated with significant toxicity or drug interactions leading to sub-therapeutic antifungal drug concentrations and poorer clinical outcomes for patients with haematological malignancy. These risks may be minimised by clinical assessment, laboratory monitoring, avoidance of particular drug combinations and dose modification. Specific measures, such as the optimal timing of oral drug administration in relation to meals, use of pre-hydration and electrolyte supplementation may also be required. Therapeutic drug monitoring (TDM) of antifungal agents is warranted, especially where non-compliance, non-linear pharmacokinetics, inadequate absorption, a narrow therapeutic window, suspected drug interaction or unexpected toxicity are encountered. Recommended indications for voriconazole and posaconazole TDM in the clinical management of haematology patients are provided. With emerging knowledge regarding the impact of pharmacogenomics upon metabolism of azole agents (particularly voriconazole), potential applications of pharmacogenomic evaluation to clinical practice are proposed. PMID:25482746

  10. RUGGED CERAMIC WINDOW FOR RF APPLICATIONS

    SciTech Connect

    MIKE NEUBAUER

    2012-11-01

    High-current RF cavities that are needed for many accelerator applications are often limited by the power transmission capability of the pressure barriers (windows) that separate the cavity from the power source. Most efforts to improve RF window design have focused on alumina ceramic, the most popular historical choice, and have not taken advantage of new materials. Alternative window materials have been investigated using a novel Merit Factor comparison and likely candidates have been tested for the material properties which will enable construction in the self-matched window configuration. Window assemblies have also been modeled and fabricated using compressed window techniques which have proven to increase the power handling capability of waveguide windows. Candidate materials have been chosen to be used in fabricating a window for high power testing at Thomas Jefferson National Accelerator Facility.

  11. Rugged Ceramic Window for RF Applications

    SciTech Connect

    Neubauer, Michael; Johnson, Rolland P.; Rimmer, Robert; Elliot, Tom; Stirbet, Mircea

    2009-05-04

    High-current RF cavities that are needed for many accelerator applications are often limited by the power transmission capability of the pressure barriers (windows) that separate the cavity from the power source. Most efforts to improve RF window design have focused on alumina ceramic, the most popular historical choice, and have not taken advantage of new materials. Alternative window materials have been investigated using a novel Merit Factor comparison and likely candidates have been tested for the material properties which will enable construction in the self-matched window configuration. Window assemblies have also been modeled and fabricated using compressed window techniques which have proven to increase the power handling capability of waveguide windows. Candidate materials have been chosen to be used in fabricating a window for high power testing at Thomas Jefferson National Accelerator Facility.

  12. Beryllium window for an APS diagnostics beamline

    SciTech Connect

    Sheng, I.C.; Yang, B.X.; Sharma, Y.S.

    1997-09-01

    A beryllium (Be) window for an Advanced Photon Source (APS) diagnostics beamline has been designed and built. The window, which has a double concave axisymmetrical profile with a thickness of 0.5 mm at the center, receives 160 W/mm{sup 2} (7 GeV/100 mA stored beam) from an undulator beam. The window design as well as thermal and thermomechanical analyses, including thermal buckling of the Be window, are presented.

  13. Fourth near-infrared optical window for assessment of bone and other tissues

    NASA Astrophysics Data System (ADS)

    Sordillo, Diana C.; Sordillo, Laura A.; Sordillo, Peter P.; Alfano, Robert R.

    2016-02-01

    Recently, additional near-infrared (NIR) optical windows beyond the conventional first therapeutic window have been utilized for deep tissue imaging through scattering media. Biomedical applications using a second optical window (1100 to 1300 nm) and a third (1600 to 1870 nm) are emerging. A fourth window (2100 to 2300 nm) has been largely ignored due to high water absorption and a lack of high sensitivity imaging detectors and ultrafast laser sources. In this study, optical properties of bone in this fourth NIR optical window, were investigated. Results were compared to those seen at the first, second and third windows, and are consistent with our previous work on malignant and benign breast and prostate tissues. Bone and malignant tissues showed highest uptake in the third and fourth windows. As collagen is a major chromophore with prominent spectral peaks between 2100 and 2300 nm, it may be that the fourth optical window is particularly useful for studying tissues with a higher collagen content, such as bone or malignant tumors.

  14. ABSORPTION ANALYZER

    DOEpatents

    Brooksbank, W.A. Jr.; Leddicotte, G.W.; Strain, J.E.; Hendon, H.H. Jr.

    1961-11-14

    A means was developed for continuously computing and indicating the isotopic assay of a process solution and for automatically controlling the process output of isotope separation equipment to provide a continuous output of the desired isotopic ratio. A counter tube is surrounded with a sample to be analyzed so that the tube is exactly in the center of the sample. A source of fast neutrons is provided and is spaced from the sample. The neutrons from the source are thermalized by causing them to pass through a neutron moderator, and the neutrons are allowed to diffuse radially through the sample to actuate the counter. A reference counter in a known sample of pure solvent is also actuated by the thermal neutrons from the neutron source. The number of neutrons which actuate the detectors is a function of a concentration of the elements in solution and their neutron absorption cross sections. The pulses produced by the detectors responsive to each neu tron passing therethrough are amplified and counted. The respective times required to accumulate a selected number of counts are measured by associated timing devices. The concentration of a particular element in solution may be determined by utilizing the following relation: T2/Ti = BCR, where B is a constant proportional to the absorption cross sections, T2 is the time of count collection for the unknown solution, Ti is the time of count collection for the pure solvent, R is the isotopic ratlo, and C is the molar concentration of the element to be determined. Knowing the slope constant B for any element and when the chemical concentration is known, the isotopic concentration may be readily determined, and conversely when the isotopic ratio is known, the chemical concentrations may be determined. (AEC)

  15. Space station proximity operations and window design

    NASA Technical Reports Server (NTRS)

    Haines, Richard F.

    1988-01-01

    On-orbit proximity operations (PROX-OPS) consist of all extravehicular activity (EVA) within 1 km of the space station. Because of the potentially large variety of PROX-OPS, very careful planning for space station windows is called for and must consider a great many human factors. The following topics are discussed: (1) basic window design philosophy and assumptions; (2) the concept of the local horizontal - local vertical on-orbit; (3) window linear dimensions; (4) selected anthropomorphic considerations; (5) displays and controls relative to windows; and (6) full window assembly replacement.

  16. Purged window apparatus utilizing heated purge gas

    DOEpatents

    Ballard, Evan O.

    1984-01-01

    A purged window apparatus utilizing tangentially injected heated purge gases in the vicinity of electromagnetic radiation transmitting windows, and a tapered external mounting tube to accelerate these gases to provide a vortex flow on the window surface and a turbulent flow throughout the mounting tube. Use of this apparatus prevents backstreaming of gases under investigation which are flowing past the mouth of the mounting tube which would otherwise deposit on the windows. Lengthy spectroscopic investigations and analyses can thereby be performed without the necessity of interrupting the procedures in order to clean or replace contaminated windows.

  17. Rigid thin windows for vacuum applications

    DOEpatents

    Meyer, Glenn Allyn; Ciarlo, Dino R.; Myers, Booth Richard; Chen, Hao-Lin; Wakalopulos, George

    1999-01-01

    A thin window that stands off atmospheric pressure is fabricated using photolithographic and wet chemical etching techniques and comprises at least two layers: an etch stop layer and a protective barrier layer. The window structure also comprises a series of support ribs running the width of the window. The windows are typically made of boron-doped silicon and silicon nitride and are useful in instruments such as electron beam guns and x-ray detectors. In an electron beam gun, the window does not impede the electrons and has demonstrated outstanding gun performance and survivability during the gun tube manufacturing process.

  18. Silicon with extra low losses for megawatt output gyrotron windows

    SciTech Connect

    Parshin, V.V.; Heidinger, R.; Andreev, B.A.; Gusev, A.V.; Shmagin, V.B.

    1995-12-31

    The dielectric losses are investigated in high-purity grades of silicon doped by different ways to reduce their mm-wave absorption. The results of the dielectric loss tangent measurements are given for the frequency range of 30 - 330 GHz and for the temperature interval 30-330K. The obtained data are discussed together with the thermophysical properties with respect to the power transmission capabilitity of edge-cooled output windows for high power gyrotrons and the potential of the special silicon grades are demonstrated for these applications.

  19. NON-INTRUSIVE SENSOR FOR GAS FILL VERIFICATION OF INSULATED GLASS WINDOWS

    SciTech Connect

    Andrew Freedman; Paul L. Kebabian; Richard R. Romano; James Woodroffe

    2003-10-01

    A sensor capable of measuring the amount of oxygen (an unwanted component that is only present because of improper filling or seal failure) within an argon-filled insulated glass window has been designed, built and successfully tested. It operates by using the optical absorption of oxygen in the atmospheric A-band centered at 762 nm. Light emitted by an argon-filled surface glow discharge lamp is Zeeman-tuned on and off an oxygen absorption line using an AC-modulated electromagnet. In the presence of oxygen, the change in the measured intensity of the lamp, obtained using standard demodulation techniques, is proportional to the oxygen column density. Measurements using an industry-standard insulated glass window indicate that the sensor can measure the amount of oxygen in a nominally argon-filled IG window (with a window gap of 10 mm) with a precision of 0.50% oxygen using a 16 second integration time. This level of precision is well within the limits required by the IG window manufacturing industry for proper monitoring of newly manufactured window units.

  20. Bond-selective imaging of deep tissue through the optical window between 1600 and 1850 nm

    PubMed Central

    Wang, Pu; Wang, Han-Wei; Sturek, Michael; Cheng, Ji-Xin

    2012-01-01

    We report the employment of an optical window between 1600 nm and 1850 nm for bond-selective deep tissue imaging through harmonic vibrational excitation and acoustic detection of resultant pressure waves. In this window where a local minimum of water absorption resides, we found a 5 times enhancement of photoacoustic signal by first overtone excitation of the methylene group CH2 at 1730 nm, compared to the second overtone excitation at 1210 nm. The enhancement allows 3D mapping of intramuscular fat with improved contrast and of lipid deposition inside an atherosclerotic artery wall in the presence of blood. Moreover, lipid and protein are differentiated based on the first overtone absorption profiles of CH2 and methyl group CH3 in this window. VPA imaging of atherosclerotic plaque with the presence of blood. PMID:22125288

  1. Durable coatings for IR windows

    NASA Astrophysics Data System (ADS)

    Goldman, Lee M.; Jha, Santosh K.; Gunda, Nilesh; Cooke, Rick; Agarwal, Neeta; Sastri, Suri A.; Harker, Alan; Kirsch, Jim

    2005-05-01

    Durable coatings of silicon-carbon-oxy-nitride (a.k.a. SiCON) are being developed to protect high-speed missile windows from the environmental loads during flight. Originally developed at Rockwell Scientific Corporation (RSC) these coatings exhibited substantial promise, but were difficult to deposit. Under a DoD DARPA SBIR Phase I program, Surmet Corporation, working closely with RSC, is depositing these coatings using an innovative vacuum vapor deposition process. High rate of coating deposition and the ease of manipulating the process variables, make Surmet"s process suitable for the deposition of substantially thick films (up to 30 μm) with precisely controlled chemistry. Initial work has shown encouraging results, and the refinement of the coating and coating process is still underway. Coupons of SiN and SiCON coatings with varying thickness on a variety of substrates such as Si-wafer, ZnS and ALON were fabricated and used for the study. This paper will present and discuss the results of SiN and SiCON coatings deposition and characterization (physical, mechanical and optical properties) as a basis for evaluating their suitability for high speed missile windows application.

  2. Interferometer for Space Station Windows

    NASA Technical Reports Server (NTRS)

    Hall, Gregory

    2003-01-01

    Inspection of space station windows for micrometeorite damage would be a difficult task insitu using current inspection techniques. Commercially available optical profilometers and inspection systems are relatively large, about the size of a desktop computer tower, and require a stable platform to inspect the test object. Also, many devices currently available are designed for a laboratory or controlled environments requiring external computer control. This paper presents an approach using a highly developed optical interferometer to inspect the windows from inside the space station itself using a self- contained hand held device. The interferometer would be capable as a minimum of detecting damage as small as one ten thousands of an inch in diameter and depth while interrogating a relatively large area. The current developmental state of this device is still in the proof of concept stage. The background section of this paper will discuss the current state of the art of profilometers as well as the desired configuration of the self-contained, hand held device. Then, a discussion of the developments and findings that will allow the configuration change with suggested approaches appearing in the proof of concept section.

  3. Absorption refrigeration machine driven by solar heat

    NASA Astrophysics Data System (ADS)

    Keizer, C.; Liem, S. H.

    1980-04-01

    A mathematical model of a single and a two stage solar absorption refrigeration system is developed in which data of collectors and weather data can be implicated. The influence of the generator, the absorber efficiencies, and the cooling temperature on the coefficient of performance (COP) of a single and two stage absorption refrigeration process are investigated. For low generator temperatures the absorber efficiency has more influence on COP than the generator efficiency. Only spectral selective double window and high performance collectors can be used for air cooled solar absorption refrigeration systems at an evaporator temperature of -5 C. It is concluded that a water cooled solar absorption refrigeration system in combination with a solar tapwater installation for household use can be achieved with 6 to 8 square meters high performance collector area.

  4. Downsampling Photodetector Array with Windowing

    NASA Technical Reports Server (NTRS)

    Patawaran, Ferze D.; Farr, William H.; Nguyen, Danh H.; Quirk, Kevin J.; Sahasrabudhe, Adit

    2012-01-01

    In a photon counting detector array, each pixel in the array produces an electrical pulse when an incident photon on that pixel is detected. Detection and demodulation of an optical communication signal that modulated the intensity of the optical signal requires counting the number of photon arrivals over a given interval. As the size of photon counting photodetector arrays increases, parallel processing of all the pixels exceeds the resources available in current application-specific integrated circuit (ASIC) and gate array (GA) technology; the desire for a high fill factor in avalanche photodiode (APD) detector arrays also precludes this. Through the use of downsampling and windowing portions of the detector array, the processing is distributed between the ASIC and GA. This allows demodulation of the optical communication signal incident on a large photon counting detector array, as well as providing architecture amenable to algorithmic changes. The detector array readout ASIC functions as a parallel-to-serial converter, serializing the photodetector array output for subsequent processing. Additional downsampling functionality for each pixel is added to this ASIC. Due to the large number of pixels in the array, the readout time of the entire photodetector is greater than the time between photon arrivals; therefore, a downsampling pre-processing step is done in order to increase the time allowed for the readout to occur. Each pixel drives a small counter that is incremented at every detected photon arrival or, equivalently, the charge in a storage capacitor is incremented. At the end of a user-configurable counting period (calculated independently from the ASIC), the counters are sampled and cleared. This downsampled photon count information is then sent one counter word at a time to the GA. For a large array, processing even the downsampled pixel counts exceeds the capabilities of the GA. Windowing of the array, whereby several subsets of pixels are designated

  5. Aerodynamic window for high precision laser drilling

    NASA Astrophysics Data System (ADS)

    Sommer, Steffen; Dausinger, Friedrich; Berger, Peter; Hügel, Helmuth

    2007-05-01

    High precision laser drilling is getting more and more interesting for industry. Main applications for such holes are vaporising and injection nozzles. To enhance quality, the energy deposition has to be accurately defined by reducing the pulse duration and thereby reducing the amount of disturbing melting layer. In addition, an appropriate processing technology, for example the helical drilling, yields holes in steel at 1 mm thickness and diameters about 100 μm with correct roundness and thin recast layers. However, the processing times are still not short enough for industrial use. Experiments have shown that the reduction of the atmospheric pressure down to 100 hPa enhances the achievable quality and efficiency, but the use of vacuum chambers in industrial processes is normally quite slow and thus expensive. The possibility of a very fast evacuation is given by the use of an aerodynamic window, which produces the pressure reduction by virtue of its fluid dynamic features. This element, based on a potential vortex, was developed and patented as out-coupling window for high power CO II lasers by IFSW 1, 2, 3. It has excellent tightness and transmission properties, and a beam deflection is not detectable. The working medium is compressed air, only. For the use as vacuum element for laser drilling, several geometrical modifications had to be realized. The prototype is small enough to be integrated in a micromachining station and has a low gas flow. During the laser pulse, which is focussed through the potential flow, a very high fluence is reached, but the measurements have not shown any beam deflection or focal shifting. The evacuation time is below 300 ms so that material treatment with changing ambient pressure is possible, too. Experimental results have proven the positive effect of the reduced ambient pressure on the drilling process for the regime of nano- and picosecond laser pulses. Plasma effects are reduced and, because of the less absorption, the

  6. Challenger Center's Window on the Universe

    NASA Astrophysics Data System (ADS)

    Livengood, T. A.; Goldstein, J. J.; Smith, S.; Bobrowsky, M.; Radnofsky, M.; Perelmuter, J.-M.; Jaggar, L.

    2001-11-01

    Challenger Center for Space Science Education's Window on the Universe program aims to create a network of under-served communities across the nation dedicated to sustained science, math, and technology education. Window communities presently include Broken Arrow, OK; Muncie, IN; Moscow, ID; Nogales, AZ; Tuskegee, AL; Marquette, MI; Altamont, KS; Washington, D.C.; and other emerging sites. Window uses themes of human space flight and the space sciences as interdisciplinary means to inspire entire communities. Practicing scientists and engineers engaged in these disciplines are invited to volunteer to become a part of these communities for a week, each visitor reaching roughly 2000 K-12 students through individual classroom visits and Family Science Night events during an intense Window on the Universe Week. In the same Window Week, Challenger Center scientists and educators present a workshop for local educators to provide training in the use of a K-12 educational module built around a particular space science and exploration theme. Window communities follow a 3-year development: Year 1, join the network, experience Window Week presented by Challenger Center and visiting researchers; Year 2, same as Year 1 plus workshop on partnering with local organizations to develop sources of visiting researchers and to enhance connections with local resources; Year 3 and subsequent, the community stages its own Window Week, with Challenger Center providing new education modules and training workshops for "master educators" from the Window community, after which the master educators return home to conduct training workshops of their own. Challenger Center remains a resource and clearinghouse for Window communities to acquire experience, technical information, and opportunities for distance collaboration with other Window communities. Window on the Universe is dedicated to assessing degree of success vs. failure in each program component and as a whole, using pre- and post

  7. Scanning imaging absorption spectrometer for atmospheric chartography

    NASA Technical Reports Server (NTRS)

    Burrows, John P.; Chance, Kelly V.

    1991-01-01

    The SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY is an instrument which measures backscattered, reflected, and transmitted light from the earth's atmosphere and surface. SCIAMACHY has eight spectral channels which observe simultaneously the spectral region between 240 and 1700 nm and selected windows between 1940 and 2400 nm. Each spectral channel contains a grating and linear diode array detector. SCIAMACHY observes the atmosphere in nadir, limb, and solar and lunar occultation viewing geometries.

  8. Oral anticancer drugs: mechanisms of low bioavailability and strategies for improvement.

    PubMed

    Stuurman, Frederik E; Nuijen, Bastiaan; Beijnen, Jos H; Schellens, Jan H M

    2013-06-01

    The use of oral anticancer drugs has increased during the last decade, because of patient preference, lower costs, proven efficacy, lack of infusion-related inconveniences, and the opportunity to develop chronic treatment regimens. Oral administration of anticancer drugs is, however, often hampered by limited bioavailability of the drug, which is associated with a wide variability. Since most anticancer drugs have a narrow therapeutic window and are dosed at or close to the maximum tolerated dose, a wide variability in the bioavailability can have a negative impact on treatment outcome. This review discusses mechanisms of low bioavailability of oral anticancer drugs and strategies for improvement. The extent of oral bioavailability depends on many factors, including release of the drug from the pharmaceutical dosage form, a drug's stability in the gastrointestinal tract, factors affecting dissolution, the rate of passage through the gut wall, and the pre-systemic metabolism in the gut wall and liver. These factors are divided into pharmaceutical limitations, physiological endogenous limitations, and patient-specific limitations. There are several strategies to reduce or overcome these limitations. First, pharmaceutical adjustment of the formulation or the physicochemical characteristics of the drug can improve the dissolution rate and absorption. Second, pharmacological interventions by combining the drug with inhibitors of transporter proteins and/or pre-systemic metabolizing enzymes can overcome the physiological endogenous limitations. Third, chemical modification of a drug by synthesis of a derivative, salt form, or prodrug could enhance the bioavailability by improving the absorption and bypassing physiological endogenous limitations. Although the bioavailability can be enhanced by various strategies, the development of novel oral products with low solubility or cell membrane permeability remains cumbersome and is often unsuccessful. The main reasons are

  9. Monitored Energy Performance of Electrochromic Windows Controlledfor Daylight and Visual Comfort

    SciTech Connect

    Lee, Eleanor S.; DiBartolomeo, Dennis L.; Klems, Joseph; Yazdanian, Mehry; Selkowitz, Stephen E.

    2005-09-23

    A 20-month field study was conducted to measure the energy performance of south-facing large-area tungsten-oxide absorptive electrochromic (EC) windows with a broad switching range in a private office setting. The EC windows were controlled by a variety of means to bring in daylight while minimizing window glare. For some cases, a Venetian blind was coupled with the EC window to block direct sun. Some tests also involved dividing the EC window wall into zones where the upper EC zone was controlled to admit daylight while the lower zone was controlled to prevent glare yet permit view. If visual comfort requirements are addressed by EC control and Venetian blinds, a 2-zone EC window configuration provided average daily lighting energy savings of 10 {+-} 15% compared to the reference case with fully lowered Venetian blinds. Cooling load reductions were 0 {+-} 3%. If the reference case assumes no daylighting controls, lighting energy savings would be 44 {+-} 11%. Peak demand reductions due to window cooling load, given a critical demand-response mode, were 19-26% maximum on clear sunny days. Peak demand reductions in lighting energy use were 0% or 72-100% compared to a reference case with and without daylighting controls, respectively. Lighting energy use was found to be very sensitive to how glare and sun is controlled. Additional research should be conducted to fine-tune EC control for visual comfort based on solar conditions so as to increase lighting energy savings.

  10. Visual and energy performance of switchable windows with antireflection coatings

    SciTech Connect

    Jonsson, Andreas; Roos, Arne

    2010-08-15

    The aim of this project was to investigate how the visual appearance and energy performance of switchable or smart windows can be improved by using antireflective coatings. For this study clear float glass, low-e glass and electrochromic glass were treated with antireflection (AR) coatings. Such a coating considerably increases the transmittance of solar radiation in general and the visible transmittance in particular. For switchable glazing based on absorptive electrochromic layers in their dark state it is necessary to use a low-emissivity coating on the inner pane of a double glazed window in order to reject the absorbed heat. In principle all surfaces can be coated with AR coatings, and it was shown that a thin AR coating on the low-e surface neither influences the thermal emissivity nor the U-value of the glazing. The study showed that the use of AR coatings in switchable glazing significantly increases the light transmittance in the transparent state. It is believed that this is important for a high level of user acceptance of such windows. (author)

  11. Hybrid window layer for photovoltaic cells

    SciTech Connect

    Deng, Xunming; Liao, Xianbo; Du, Wenhui

    2011-02-01

    A novel photovoltaic solar cell and method of making the same are disclosed. The solar cell includes: at least one absorber layer which could either be a lightly doped layer or an undoped layer, and at least a doped window-layers which comprise at least two sub-window-layers. The first sub-window-layer, which is next to the absorber-layer, is deposited to form desirable junction with the absorber-layer. The second sub-window-layer, which is next to the first sub-window-layer, but not in direct contact with the absorber-layer, is deposited in order to have transmission higher than the first-sub-window-layer.

  12. Hybrid window layer for photovoltaic cells

    SciTech Connect

    Deng, Xunming; Liao, Xianbo; Du, Wenhui

    2011-10-04

    A novel photovoltaic solar cell and method of making the same are disclosed. The solar cell includes: at least one absorber layer which could either be a lightly doped layer or an undoped layer, and at least a doped window-layers which comprise at least two sub-window-layers. The first sub-window-layer, which is next to the absorber-layer, is deposited to form desirable junction with the absorber-layer. The second sub-window-layer, which is next to the first sub-window-layer, but not in direct contact with the absorber-layer, is deposited in order to have transmission higher than the first-sub-window-layer.

  13. Hybrid window layer for photovoltaic cells

    DOEpatents

    Deng, Xunming

    2010-02-23

    A novel photovoltaic solar cell and method of making the same are disclosed. The solar cell includes: at least one absorber layer which could either be a lightly doped layer or an undoped layer, and at least a doped window-layers which comprise at least two sub-window-layers. The first sub-window-layer, which is next to the absorber-layer, is deposited to form desirable junction with the absorber-layer. The second sub-window-layer, which is next to the first sub-window-layer, but not in direct contact with the absorber-layer, is deposited in order to have transmission higher than the first-sub-window-layer.

  14. Lithography process window analysis with calibrated model

    NASA Astrophysics Data System (ADS)

    Zhou, Wenzhan; Yu, Jin; Lo, James; Liu, Johnson

    2004-05-01

    As critical-dimension shrink below 0.13 μm, the SPC (Statistical Process Control) based on CD (Critical Dimension) control in lithography process becomes more difficult. Increasing requirements of a shrinking process window have called on the need for more accurate decision of process window center. However in practical fabrication, we found that systematic error introduced by metrology and/or resist process can significantly impact the process window analysis result. Especially, when the simple polynomial functions are used to fit the lithographic data from focus exposure matrix (FEM), the model will fit these systematic errors rather than filter them out. This will definitely impact the process window analysis and determination of the best process condition. In this paper, we proposed to use a calibrated first principle model to do process window analysis. With this method, the systematic metrology error can be filtered out efficiently and give a more reasonable window analysis result.

  15. Laser sealed vacuum insulation window

    DOEpatents

    Benson, David K.; Tracy, C. Edwin

    1987-01-01

    A laser sealed evacuated window panel is comprised of two glass panes held spaced apart in relation to each other by a plurality of spherical glass beads and glass welded around the edges to provide an evacuated space between the glass panes that is completely glass sealed from the exterior. The glass welded edge seal is obtained by welding the edges of the glass panes together with a laser beam while the glass panes and bead spacers are positioned in a vacuum furnace and heated to the annealing point of the glass to avoid stress fracture in the area of the glass weld. The laser welding in the furnace can be directed around the perimeter of the glass panel by a combination of rotating the glass panel and linearly translating or aiming the laser with a relay mirror.

  16. Laser sealed vacuum insulating window

    DOEpatents

    Benson, D.K.; Tracy, C.E.

    1985-08-19

    A laser sealed evacuated window panel is comprised of two glass panes held spaced apart in relation to each other by a plurality of spherical glass beads and glass welded around the edges to provide an evacuated space between the glass panes that is completely glass sealed from the exterior. The glass welded edge seal is obtained by welding the edges of the glass panes together with a laser beam while the glass panes and bead spacers are positioned in a vacuum furnace and heated to the annealing point of the glass to avoid stress fracture in the area of the glass weld. The laser welding in the furnace can be directed around the perimeter of the galss panel by a combination of rotating the glass panel and linearly translating or aiming the laser with a relay mirror.

  17. Window Observational Rack Facility (WORF)

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Developed by Boeing, at the Marshall Space Flight Center (MSFC) Space Station Manufacturing building, the Window Observational Rack Facility (WORF) will help Space Station crews take some of the best photographs ever snapped from an orbiting spacecraft by eliminating glare and allowing researchers to control their cameras and other equipment from the ground. The WORF is designed to make the best possible use of the high-quality research window in the Space Station's U.S. Destiny laboratory module. Engineers at the MSFC proposed a derivative of the EXPRESS (Expedite the Processing of Experiments to the Space Station) Rack already used on the Space Station and were given the go-ahead. The EXPRESS rack can hold a wide variety of experiments and provide them with power, communications, data, cooling, fluids, and other utilities - all the things that Earth-observing experiment instruments would need. WORF will supply payloads with power, data, cooling, video downlink, and stable, standardized interfaces for mounting imaging instruments. Similar to specialized orbital observatories, the interior of the rack is sealed against light and coated with a special low-reflectant black paint, so payloads will be able to observe low-light-level subjects such as the faint glow of auroras. Cameras and remote sensing instruments in the WORF can be preprogrammed, controlled from the ground, or operated by a Station crewmember by using a flexible shroud designed to cinch tightly around the crewmember's waist. The WORF is scheduled to be launched aboard the STS-114 Space Shuttle mission in the year 2003.

  18. Contoured insulation window for evacuated solar collector

    SciTech Connect

    Coppola, F. T.; Lentz, W. P.; Vandewoestine, R. V.

    1980-02-05

    An insulating contoured window is provided for use with an enclosed chamber such as an evacuated flat plate solar heat collector with the contoured solar window being of minimum thickness and supported solely about its peripheral edge portions. The window is contoured in both its longitudinal and transverse directions, such that in its longitudinal direction the window is composed of a plurality of sinusoidal corrugations whereas in its transverse direction the peaks of such corrugations are contoured in the form of paraboloids so that the structure may withstand the forces generated thereon by the atmosphere.

  19. Manufacturing of diamond windows for synchrotron radiation

    SciTech Connect

    Schildkamp, W.; Nikitina, L.

    2012-09-15

    A new diamond window construction is presented and explicit manufacturing details are given. This window will increase the power dissipation by about a factor of 4 over present day state of the art windows to absorb 600 W of power. This power will be generated by in-vacuum undulators with the storage ring ALBA operating at a design current of 400 mA. Extensive finite element (FE) calculations are included to predict the windows behavior accompanied by explanations for the chosen boundary conditions. A simple linear model was used to cross-check the FE calculations.

  20. Thermally insulated window sash construction for a casement window

    SciTech Connect

    Biro, A.J.

    1987-09-01

    A window sash member is described comprising: first and second generally parallel sidewalls; first and second spaced, generally parallel transverse walls connecting the first and second sidewalls, extending between and oriented generally perpendicular to the first and second sidewalls to define a first hollow chamber; a third transverse wall, located without the first hollow chamber adjacent to and generally parallel to the first transverse wall, extending from the first sidewall and terminating short of the second sidewall; a first interior wall extending from the third transverse wall to the first transverse wall and oriented generally parallel to the first sidewall to define a second hollow chamber; a fourth transverse wall, located without the first hollow chamber adjacent to and generally to the second transverse wall, extending from the first sidewall and terminating short of the second sidewall; and a second interior wall extending from the fourth transverse wall to the second transverse wall and oriented generally parallel to the second sidewall to define a third hollow chamber.

  1. Window type: 2x3 fixed multipaned steel window flanked by 1x3 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Window type: 2x3 fixed multipaned steel window flanked by 1x3 multipaned steel casements. Concrete sill and spandrel also illustrated. Building 43, facing east - Harbor Hills Housing Project, 26607 Western Avenue, Lomita, Los Angeles County, CA

  2. Development of cooled UV, visible and IR windows for quasicontinuous operation of the W7-X stellarator

    SciTech Connect

    Koenig, R.; Ogorodnikova, O.; Hildebrandt, D.; Grosser, K.; Sehren, C. von; Baldzuhn, J.; Burhenn, R.; Mertens, Ph.; Pospieszczyk, A.; Schweer, B.; Schmidt, H.; Klinger, T.

    2004-10-01

    The stellarator W7-X will be capable of running 30 min discharges. The expected continuous radiation power loads on plasma-facing optical components of 50 kW/m{sup 2} will be predominantly deposited in the form of short wavelength radiation (<60 nm) within the first millimeter of any window material. At such high heat loads actively water cooled windows are essential. The finite element-code ANSYS was used to calculate temperature and stress distributions across the windows for different window materials (CaF{sub 2}, MgF{sub 2}, quartz, ZnSe, sapphire), diameters, and thicknesses to explore any window design limitations resulting from the material properties of the different window substrates. First tests of a prototype water cooled window (coated with water-based colloidal graphite for effective IR absorption) in a specially designed vacuum test chamber equipped with a large surface vacuum compatible high power IR heater are being reported on. The temporal evolution of the temperature at different locations on the air side of the window and its surrounding structure is being monitored by several PT100 resistive thermometers while the spatial heat distribution across the cooled windows on their air and vacuum side is being measured with two IR cameras operating at 4 and 10 {mu}m.

  3. Glass-windowed ultrasound transducers.

    PubMed

    Yddal, Tostein; Gilja, Odd Helge; Cochran, Sandy; Postema, Michiel; Kotopoulis, Spiros

    2016-05-01

    In research and industrial processes, it is increasingly common practice to combine multiple measurement modalities. Nevertheless, experimental tools that allow the co-linear combination of optical and ultrasonic transmission have rarely been reported. The aim of this study was to develop and characterise a water-matched ultrasound transducer architecture using standard components, with a central optical window larger than 10 mm in diameter allowing for optical transmission. The window can be used to place illumination or imaging apparatus such as light guides, miniature cameras, or microscope objectives, simplifying experimental setups. Four design variations of a basic architecture were fabricated and characterised with the objective to assess whether the variations influence the acoustic output. The basic architecture consisted of a piezoelectric ring and a glass disc, with an aluminium casing. The designs differed in piezoelectric element dimensions: inner diameter, ID=10 mm, outer diameter, OD=25 mm, thickness, TH=4 mm or ID=20 mm, OD=40 mm, TH=5 mm; glass disc dimensions OD=20-50 mm, TH=2-4 mm; and details of assembly. The transducers' frequency responses were characterised using electrical impedance spectroscopy and pulse-echo measurements, the acoustic propagation pattern using acoustic pressure field scans, the acoustic power output using radiation force balance measurements, and the acoustic pressure using a needle hydrophone. Depending on the design and piezoelectric element dimensions, the resonance frequency was in the range 350-630 kHz, the -6 dB bandwidth was in the range 87-97%, acoustic output power exceeded 1 W, and acoustic pressure exceeded 1 MPa peak-to-peak. 3D stress simulations were performed to predict the isostatic pressure required to induce material failure and 4D acoustic simulations. The pressure simulations indicated that specific design variations could sustain isostatic pressures up to 4.8 MPa.The acoustic simulations were able to

  4. Optical Evaluation of DMDs with UV-Grade FS, Sapphire, MgF2 Windows and Reflectance of Bare Devices

    NASA Technical Reports Server (NTRS)

    Quijada, Manuel A.; Heap, Sara; Travinsky, Anton; Vorobiev, Dmitry; Ninkov, Zoran; Raisanen, Alan; Roberto, Massimo

    2016-01-01

    Digital Micro-mirror Devices (DMDs) have been identified as an alternative to microshutter arrays for space-based multi-object spectrometers (MOS). Specifically, the MOS at the heart of a proposed Galactic Evolution Spectroscopic Explorer (GESE) that uses the DMD as a reprogrammable slit mask. Unfortunately, the protective borosilicate windows limit the use of DMDs in the UV and IR regimes, where the glass has insufficient throughput. In this work, we present our efforts to replace standard DMD windows with custom windows made from UV-grade fused silica, Low Absorption Optical Sapphire (LAOS) and magnesium fluoride. We present reflectance measurements of the antireflection coated windows and a reflectance study of the DMDs active area (window removed). Furthermore, we investigated the long-term stability of the DMD reflectance and recoating device with fresh Al coatings.

  5. Humeral windows in revision total elbow arthroplasty.

    PubMed

    Peach, Chris A; Salama, Amir; Stanley, David

    2016-04-01

    The use of cortical windows for revision elbow arthroplasty has not previously been widely reported. Their use aids safe revision of a well fixed humeral prosthesis and can be used in the setting of dislocation, periprosthetic fracture or aseptic loosening of the ulnar component. We describe our technique and results of cortical windows in the distal humerus for revision elbow arthroplasty surgery. PMID:27583011

  6. Microfibrillar collagen in the oval window.

    PubMed

    Liston, S L

    1982-01-01

    Compressed microfibrillar collagen was used to seal openings in cat oval windows. Histologic examination showed the material was well tolerated and produced a good oval window seal. Because of its hemostatic properties, this material should prove to be useful when bleeding is encountered during a stapedectomy. PMID:10994440

  7. Thermal measurements of microwave transmitter feedhorn window

    NASA Technical Reports Server (NTRS)

    Perez, R. M.; Hoppe, D. J.

    1989-01-01

    Thermal measurements of microwave transmitter feedhorn windows were performed using an imaging infrared radiometer. The measurement technique is described and results are presented for windows made of 0.001-in. Kapton (trademark of Dupont Chemical Co.) and 0.1-in. HTP-6 (Space Shuttle tile material). Measured and calculated temperatures agree well.

  8. Window Cleaner—New and Improved?

    NASA Astrophysics Data System (ADS)

    Jacobsen, Erica K.

    2007-11-01

    A recent coupon advertisement for window cleaner in the Sunday newspaper was reminiscent of a past JCE Classroom Activity . The new product says it offers a cheaper way to clean your windows and is a way to cut down on the number of plastic spray containers you throw away.

  9. Measure Guideline: Window Repair, Rehabilitation, and Replacement

    SciTech Connect

    Baker, P.

    2012-12-01

    This measure guideline provides information and guidance on rehabilitating, retrofitting, and replacing existing window assemblies in residential construction. The intent is to provide information regarding means and methods to improve the energy and comfort performance of existing wood window assemblies in a way that takes into consideration component durability, in-service operation, and long term performance of the strategies.

  10. Measured Rattle Threshold of Residential House Windows

    NASA Technical Reports Server (NTRS)

    Sizov, Natalia; Schultz, Troy; Hobbs, Christopher; Klos, Jacob

    2008-01-01

    Window rattle is a common indoor noise effect in houses exposed to low frequency noise from such sources as railroads, blast noise and sonic boom. Human perception of rattle can be negative that is a motivating factor of the current research effort to study sonic boom induced window rattle. A rattle study has been conducted on residential houses containing windows of different construction at a variety of geographic locations within the United States. Windows in these houses were excited by a portable, high-powered loudspeaker and enclosure specifically designed to be mounted on the house exterior to cover an entire window. Window vibration was measured with accelerometers placed on different window components. Reference microphones were also placed inside the house and inside of the loudspeaker box. Swept sine excitation was used to identify the vibration threshold at which the response of the structure becomes non-linear and begins to rattle. Initial results from this study are presented and discussed. Future efforts will continue to explore the rattle occurrence in windows of residential houses exposed to sonic booms.

  11. Universal nonresonant absorption in carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Vialla, Fabien; Malic, Ermin; Langlois, Benjamin; Chassagneux, Yannick; Diederichs, Carole; Deleporte, Emmanuelle; Roussignol, Philippe; Lauret, Jean-Sébastien; Voisin, Christophe

    2014-10-01

    Photoluminescence excitation measurements in semiconducting carbon nanotubes show a systematic nonresonant contribution between the well-known excitonic resonances. Using a global analysis method, we were able to delineate the contribution of each chiral species, including its tiny nonresonant component. By comparison with the recently reported excitonic absorption cross section on the S22 resonance, we found a universal nonresonant absorbance which turns out to be of the order of one-half of that of an equivalent graphene sheet. This value, as well as the absorption line shape in the nonresonant window, is in excellent agreement with microscopic calculations based on the density-matrix formalism. This nonresonant absorption of semiconducting nanotubes is essentially frequency independent over 0.5-eV-wide windows and reaches approximately the same value between the S11 and S22 resonances and between the S22 and S33 resonances. In addition, the nonresonant absorption cross section turns out to be the same for all the chiral species we measured in this study. From a practical point of view, this study provides a solid framework for sample content analysis based on photoluminescence studies by targeting specific excitation wavelengths that lead to almost uniform excitation of all the chiral species of a sample within a given diameter range.

  12. Internally cooled window for endoatmospheric homing

    NASA Astrophysics Data System (ADS)

    Wojciechowski, C. J.; Leary, D. F.; Bouska, D. H.

    1992-05-01

    This paper presents an innovative approach to infrared (IR) sensor window cooling which will result in improved performance as well as miniaturization of the IR sensor window and coolant hardware. The successful development of this concept can lead to IR windows that can be mass produced at very low overall cost, with short production lead times. The concept involves internal cooling of an advanced diamond film/silicon window, a technique whose goal is to enhance the aero-optics performance by avoiding the turbulence and optical distortion induced by external film cooling injection. Preliminary analysis indicates that the proposed IR window concept can meet advanced interceptor mission requirements while providing significant design improvements in terms of reduced coolant subsystem mass and low manufacturing cost.

  13. Internally cooled window for endoatmospheric homing - Update

    NASA Astrophysics Data System (ADS)

    Wojciechowski, C. J.; Ravi, K. V.; Jones, G.

    1993-06-01

    This paper presents an innovative approach to infrared (IR) sensor window cooling which will result in improved performance as well as miniaturization of the IR sensor window and coolant hardware. The successful development of this concept can lead to IR windows that can be mass produced at very low overall cost, with short production lead times. The concept involves internal cooling of an advanced diamond film/silicon window, a technique whose goal is to enhance the aero-optics performance by avoiding the turbulence and optical distortion induced by external film cooling injection. Preliminary analysis indicates that the proposed IR window concept can meet advanced interceptor mission requirements while providing significant design improvements in terms of reduced coolant subsystem mass and low manufacturing cost.

  14. A monolithic thin film electrochromic window

    SciTech Connect

    Goldner, R.B.; Arntz, F.O.; Berera, G.; Haas, T.E.; Wong, K.K. . Electro-Optics Technology Center); Wei, G. ); Yu, P.C. )

    1991-01-01

    Three closely related thin film solid state ionic devices that are potentially important for applications are: electrochromic smart windows, high energy density thin film rechargeable batteries, and thin film electrochemical sensors. Each usually has at least on mixed ion/electron conductor, an electron-blocking ion conductor, and an ion-blocking electron conductor, and many of the technical issues associated with thin film solid state ionics are common to all three devices. Since the electrochromic window has the added technical requirement of electrically-controlled optical modulation, (over the solar spectrum), and since research at the authors' institution has focused primarily on the window structure, this paper will address the electrochromic window, and particularly a monolithic variable reflectivity electrochromic window, as an illustrative example of some of the challenges and opportunities that are confronting the thin film solid state ionics community. 33 refs.

  15. A monolithic thin film electrochromic window

    SciTech Connect

    Goldner, R.B.; Arntz, F.O.; Berera, G.; Haas, T.E.; Wong, K.K.; Wei, G.; Yu, P.C.

    1991-12-31

    Three closely related thin film solid state ionic devices that are potentially important for applications are: electrochromic smart windows, high energy density thin film rechargeable batteries, and thin film electrochemical sensors. Each usually has at least on mixed ion/electron conductor, an electron-blocking ion conductor, and an ion-blocking electron conductor, and many of the technical issues associated with thin film solid state ionics are common to all three devices. Since the electrochromic window has the added technical requirement of electrically-controlled optical modulation, (over the solar spectrum), and since research at the authors` institution has focused primarily on the window structure, this paper will address the electrochromic window, and particularly a monolithic variable reflectivity electrochromic window, as an illustrative example of some of the challenges and opportunities that are confronting the thin film solid state ionics community. 33 refs.

  16. THERM 5 / WINDOW 5 NFRC simulation manual

    SciTech Connect

    Mitchell, Robin; Kohler, Christian; Arasteh, Dariush; Carmody, John; Huizenga, Charlie; Curcija, Dragan

    2003-06-01

    This document, the ''THERM 5/WINDOW 5 NFRC Simulation Manual', discusses how to use the THERM and WINDOW programs to model products for NFRC certified simulations and assumes that the user is already familiar with those programs. In order to learn how to use these programs, it is necessary to become familiar with the material in both the ''THERM User's Manual'' and the ''WINDOW User's Manual''. In general, this manual references the User's Manuals rather than repeating the information. If there is a conflict between either of the User Manual and this ''THERM 5/''WINDOW 5 NFRC Simulation Manual'', the ''THERM 5/WINDOW 5 NFRC Simulation Manual'' takes precedence. In addition, if this manual is in conflict with any NFRC standards, the standards take precedence. For example, if samples in this manual do not follow the current taping and testing NFRC standards, the standards not the samples in this manual, take precedence.

  17. Novel sustained release, swellable and bioadhesive gastroretentive drug delivery system for ofloxacin.

    PubMed

    Chavanpatil, Mahesh D; Jain, Paras; Chaudhari, Sachin; Shear, Rajesh; Vavia, Pradeep R

    2006-06-19

    Oral sustained release gastroretentive dosage forms offer many advantages for drugs having absorption from upper gastrointestinal tract and improve the bioavailability of medications that are characterized by a narrow absorption window. A new gastroretentive sustained release delivery system was developed with floating, swellable and bioadhesive properties. All these properties were optimized and evaluated. Various release retarding polymers like psyllium husk, HPMC K100M and a swelling agent, crosspovidone in combinations were tried and optimized to get the release profile for 24 h. Formulations were evaluated for in vitro drug release profile, swelling characteristics and in vitro bioadhesion property. The in vitro drug release followed Higuchi kinetics and the drug release mechanism was found to be of anomalous or non-Fickian type. For the developed formulation, the value of n was found to be 0.5766 while for the marketed formulation the value was 0.5718 indicating the anomalous transport. The high water uptake leading to higher swelling of the tablet supported the anomalous release mechanism of ofloxacin. The similarity factor f2 was found to be 91.12 for the developed formulation indicating the release was similar to that of the marketed formulation (Zanocin OD). The swelling properties were increased with increasing crosspovidone concentration and contributed significantly in drug release from the tablet matrix. The bioadhesive property of the developed formulation was found to be significant (P < 0.005) in combination as compared to HPMC K100M and psyllium husk alone. PMID:16567072

  18. Transmission in near-infrared optical windows for deep brain imaging.

    PubMed

    Shi, Lingyan; Sordillo, Laura A; Rodríguez-Contreras, Adrián; Alfano, Robert

    2016-01-01

    Near-infrared (NIR) radiation has been employed using one- and two-photon excitation of fluorescence imaging at wavelengths 650-950 nm (optical window I) for deep brain imaging; however, longer wavelengths in NIR have been overlooked due to a lack of suitable NIR-low band gap semiconductor imaging detectors and/or femtosecond laser sources. This research introduces three new optical windows in NIR and demonstrates their potential for deep brain tissue imaging. The transmittances are measured in rat brain tissue in the second (II, 1,100-1,350 nm), third (III, 1,600-1,870 nm), and fourth (IV, centered at 2,200 nm) NIR optical tissue windows. The relationship between transmission and tissue thickness is measured and compared with the theory. Due to a reduction in scattering and minimal absorption, window III is shown to be the best for deep brain imaging, and windows II and IV show similar but better potential for deep imaging than window I. PMID:26556561

  19. Double window configuration as a low cost microwave waveguide window for plasma applications

    SciTech Connect

    Baskaran, R.

    1997-12-01

    Waveguide windows are major components of a transmission line used in microwave plasma devices. The function of the waveguide window is to provide vacuum isolation of the source side from the plasma chamber while transmitting microwaves with minimum attenuation. Commonly a single thin dielectric plate is sandwiched between a choke type flange and a flat flange and is used as a waveguide window. To arrive at a better window configuration in terms of the low power reflection coefficient, the voltage standing wave ratio calculation is carried out for different window configurations (single window and double window) and for various window thicknesses. It is found that the power reflection is the minimum in the case of double window configuration. The minimum power reflection is as low as 0.8{percent} for a combination of alumina and a quartz plate each of 1 cm thickness in the double window configuration. Also, it is more advantageous to use radial microwave coupling than axial coupling in order to increase the life time of the microwave waveguide window. {copyright} {ital 1997 American Institute of Physics.}

  20. Efficient Adjustable Reflectivity Smart Window

    SciTech Connect

    D. Morgan Tench

    2005-12-01

    This project addressed the key technical issues for development of an efficient smart window based on reversible electrochemical transfer of silver between a mirror electrode and a localized counter electrode. Effort to provide uniform switching over large areas focused on use of a resistive transparent electrode innerlayer to increase the interelectrode resistance. An effective edge seal was developed in collaboration with adhesive suppliers and an electrochromic device manufacturer. Work to provide a manufacturable counter electrode focused on fabricating a dot matrix electrode without photolithography by electrodeposition of Pt nuclei on inherent active sites on a transparent oxide conductor. An alternative counter electrode based on a conducting polymer and an ionic liquid electrolyte was also investigated. Work in all of these areas was successful. Sputtered large-bandgap oxide innerlayers sandwiched between conductive indium tin oxide (ITO) layers were shown to provide sufficient cross-layer resistance (>300 ohm/cm{sup 2}) without significantly affecting the electrochemical properties of the ITO overlayer. Two edge seal epoxies, one procured from an epoxy manufacturer and one provided by an electrochromic device manufacturer in finished seals, were shown to be effective barriers against oxygen intrusion up to 80 C. The optimum density of nuclei for the dot matrix counter electrode was attained without use of photolithography by electrodeposition from a commercial alkaline platinum plating bath. Silver loss issues for cells with dot matrix electrodes were successfully addressed by purifying the electrolyte and adjusting the cell cycling parameters. More than 30K cycles were demonstrated for a REM cell (30-cm square) with a dot matrix counter electrode. Larger cells (30-cm square) were successfully fabricated but could not be cycled since the nucleation layers (provided by an outside supplier) were defective so that mirror deposits could not be produced.

  1. Window Insulation: How to Sort Through the Options.

    ERIC Educational Resources Information Center

    Miller, Barbara

    This two-part report explores the efforts of businesses and individuals to improve the thermal performance of windows. Part I discusses the basics of what makes a window product insulate or save energy. Topic areas addressed include saving energy lost through windows, key components of window insulation, three basic types of window insulation,…

  2. Plasmonic thin films for application in improved chromogenic windows

    NASA Astrophysics Data System (ADS)

    Niklasson, Gunnar A.; Lansåker, Pia C.; Li, Shu-Yi; Granqvist, Claes G.

    2016-02-01

    Nanocomposites consisting of noble metal nanoparticles in a transparent matrix exhibit plasmonic absorption in the visible wavelength range, and conducting oxide nanoparticles display a localized plasma absorption in the near infrared. The optical properties of nanocomposites are commonly modelled by effective medium theories, which describe the effective dielectric function of the composite using as input the dielectric functions of the constituents and their respective volume fractions. Plasmonic effects can be exploited in the design of energy-efficient windows in order to obtain improved performance. Electrochromic coatings that switch in the near infrared make use of the modulation of the plasma absorption of oxide nanoparticles due to charge density modulation induced by an external voltage. Plasmonic thermochromic switching in the near infrared has the potential to be significantly larger than in the case of a thin film. Very thin noble metal films are an interesting alternative to conducting oxides as transparent contacts to electrochromic devices. However, in this latter case plasmonic effects are to be avoided rather than exploited.

  3. Focal plane scanner with reciprocating spatial window

    NASA Technical Reports Server (NTRS)

    Mao, Chengye (Inventor)

    2000-01-01

    A focal plane scanner having a front objective lens, a spatial window for selectively passing a portion of the image therethrough, and a CCD array for receiving the passed portion of the image. All embodiments have a common feature whereby the spatial window and CCD array are mounted for simultaneous relative reciprocating movement with respect to the front objective lens, and the spatial window is mounted within the focal plane of the front objective. In a first embodiment, the spatial window is a slit and the CCD array is one-dimensional, and successive rows of the image in the focal plane of the front objective lens are passed to the CCD array by an image relay lens interposed between the slit and the CCD array. In a second embodiment, the spatial window is a slit, the CCD array is two-dimensional, and a prism-grating-prism optical spectrometer is interposed between the slit and the CCD array so as to cause the scanned row to be split into a plurality of spectral separations onto the CCD array. In a third embodiment, the CCD array is two-dimensional and the spatial window is a rectangular linear variable filter (LVF) window, so as to cause the scanned rows impinging on the LVF to be bandpass filtered into spectral components onto the CCD array through an image relay lens interposed between the LVF and the CCD array.

  4. Air leakage of newly instaled residential windows

    SciTech Connect

    Weidt, J.; Weidt, J.

    1980-06-01

    The air-leakage characteristics of five major window designs were measured in a field survey conducted in Twin Cities, Minnesota. A total of 192 windows (16 manufacturers) were tested at 58 sites representing a cross-section of single-family homes, townhouses, low- and high-rise apartments, and condominiums. Air-leakage measurements of the installed windows were compared with the current standard used by industry and government of 0.50 ft/sup 3//min/linear ft of crack. Other parameters studied were: effect of sash and frame material, effect of leakage between window frame and wall, differences among the product lines of a single manufacturer and between manufacturers, effect of installation practices, effect of cold weather on performance, change in performance over time for older windows, and performance of fixed glazing. Based on industry and government standards, 40% of all windows tested showed air-leakage characteristics higher than the 0.50 cfm/lfc standard, and 60% exceeded manufacturers' specifications for performance which in some cases were lower than the general industry standard. Analysis of the impact of various parameters on air-leakage performance showed that the operational design of the window was the most critical determinant although the ranking changes if performance is expressed in cfm/unit area or cfm/opening area. Air leakage was measured using a portable pressurization chamber. Smoke pencils, thermographic techniques and extensive photographic documentation provided additional data as to the location and cause of air leakage problems.

  5. Challenger Center's Window on the Universe Program

    NASA Astrophysics Data System (ADS)

    Bobrowsky, M.; Goldstein, J.; Livengood, T.; Offringa, K.; Richards, S.; Riddle, B.

    2001-05-01

    Each year, Challenger Center's Window on the Universe launches thousands of everyday people---teachers and students, parents---on a fantastic journey through our universe. Recently, for example, we visited Nogales, Arizona, where we trained 350 teachers, talked to 6000 students in classrooms, and 1500 more students and their families as part of ``Family Science Night'' presentations. Window aims to increase community involvement in science education within underserved communities throughout the United States. Challenger Center's national team works with a local team in the participating community to provide training for teachers, classroom talks, and Family Science Night presentations for the community. The national team includes at least one astronomer and one educator from Challenger Center, as well as at least two Visiting Researchers (VRs) from other institutions. (However, in Washington, D.C., there were 40 VRs from 12 different institutions who, along with the national team, visited every 6th grade classroom in the city! Window materials have become an essential part of the 6th grade curriculum in Washington, D.C.) VRs are scientists or engineers in the fields of astronomy, space science, or human space flight who are gifted at communicating their passion about research to audiences of all ages. Their research is related to the topics covered in the Window educational modules, which provide the core content for Window on the Universe programming. VRs travel to Window communities during one of the Window weeks, where they visit classrooms and sometimes conduct Family Science Night presentations. Researchers from any institution are invited to participate as VRs in Window programs and showcase their research and their institution. If you or someone from your institution is interested in participating, please visit http://challenger.org/wotu/ and click on ``Find Out More.'' Window on the Universe is funded by grants from NASA's Human Exploration and Development

  6. Optimal spectral windows for microwave diversity imaging

    NASA Technical Reports Server (NTRS)

    Farhat, Nabil H.; Bai, Baocheng

    1991-01-01

    Tomographic microwave diversity imaging is analyzed using linear system theory concepts, and optimal spectral windows for data acquisition are obtained either by considering window position in the spectral domain or by using simulated annealing to find an optimal phase weighting of the object frequency response samples collected over the specified spectral window. This study provides a means of microwave image formation that is applicable under general assumptions. Results of numerical simulations and representative images reconstructed from realistic experimental microwave scattering data are given, demonstrating that the proposed approach is superior to previous image reconstruction methods.

  7. X-ray windows for spaceborne detectors

    NASA Astrophysics Data System (ADS)

    Viitanen, Veli-Pekka; Nenonen, Seppo; Partanen, Panu; Sipila, Heikki; Mutikainen, Risto

    1992-10-01

    Several types of ultrathin entrance windows have been developed for applications in spaceborne X-ray instruments. Active area diameters up to 140 mm have been achieved. The latest windows developed have a transmission of more than 20 percent at B K-alpha and more than 40 percent at N K-alpha. A new gas block layer type utilizing aluminum nitride has been developed, as well as semitransparent support structures for the membranes. The effects of pressure-induced strain, radiation and atomic oxygen corrosion on the gas leak properties of the windows has been studied.

  8. Implementing Boot Control for Windows Vista

    NASA Astrophysics Data System (ADS)

    Ashino, Yuki; Fujita, Keisuke; Furusawa, Maiko; Uehara, Tetsutaro; Sasaki, Ryoichi

    A digital forensic logging system must prevent the booting of unauthorized programs and the modification of evidence. Our previous research developed Dig-Force2, a boot control system for Windows XP platforms that employs API hooking and a trusted platform module. However, Dig-Force2 cannot be used for Windows Vista systems because the hooked API cannot monitor booting programs in user accounts. This paper describes an enhanced version of Dig-Force2, which uses a TPM and a white list to provide boot control functionality for Windows Vista systems. In addition, the paper presents the results of security and performance evaluations of the boot control system.

  9. Apollo experience report: Spacecraft structural windows

    NASA Technical Reports Server (NTRS)

    Pigg, O. E.; Weiss, S. P.

    1973-01-01

    The window structural design and verification experience is presented for the Apollo command and lunar modules. This report presents window design philosophy, design criteria, hardware description, and qualification and acceptance test programs and discusses the problems encountered and solutions developed in these areas. The structural characteristics of glass are not generally well understood by designers. The optics and instrument glass covers were not considered to be structural components and thus were not normally subjected to the design, qualification, and acceptance standards necessary to preclude failures. These two factors contributed significantly to window problems on both Apollo spacecraft.

  10. [Drug Interactions and Pharmacokinetics of Psychotropic Drugs].

    PubMed

    Suzuki, Eiji

    2015-01-01

    Pharmacokinetics is the field dedicated to investigating the absorption, distribution, metabolism and excretion of drugs. Absorption of drugs is affected when they are taken together with a meal. Depending on the drug, the area under the concentration curve is affected by whether a medication is taken before or after a meal. Combined use of drugs with a high plasma protein binding fraction may be dangerous, since drug efficacy is impacted by efficiency, which in turn is affected by the degree to which it binds to proteins. Even more significant is the issue of "drug/drug" interactions that arise due to inhibition of the cytochrome P450 (CYP) hepatic microsomal enzyme system. Some antidepressants, such as paroxetine and fluvoxamine, are strong inhibitors of the CYP system. In the case of a medication that depends on renal clearance for elimination, caution is required when taking such a drug if it influences renal function. When a medicinal effect changes, pharmacodynamic changes must also be considered. PMID:26514046

  11. DETAIL OF GROUND, MEZZANINE, AND FIRST FLOOW WINDOW OPENINGS AT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL OF GROUND, MEZZANINE, AND FIRST FLOOW WINDOW OPENINGS AT CORNER OF CLAY AND 15TH STREETS. WINDOWS AND WINDOW FRAMES REMOVED - John Breuner & Company Building, 1515 Clay Street, Oakland, Alameda County, CA

  12. DETAIL VIEW, WEST VENETIAN WINDOW IN SOUTH WALL. (NOTE THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL VIEW, WEST VENETIAN WINDOW IN SOUTH WALL. (NOTE THE IRON BARS ON THE CELLAR WINDOW BELOW. THIS WINDOW LETS ONTO WHAT WAS LIKELY THE ESTATE OFFICE DURING THE HAMILTONIAN RESIDENCY - The Woodlands, 4000 Woodlands Avenue, Philadelphia, Philadelphia County, PA

  13. Field Evaluation of Low-E Storm Windows

    SciTech Connect

    Drumheller, S. Craig; Kohler, Christian; Minen, Stefanie

    2007-07-11

    A field evaluation comparing the performance of low emittance (low-e) storm windows with both standard clear storm windows and no storm windows was performed in a cold climate. Six homes with single-pane windows were monitored over the period of one heating season. The homes were monitored with no storm windows and with new storm windows. The storm windows installed on four of the six homes included a hard coat, pyrolitic, low-e coating while the storm windows for the other two homeshad traditional clear glass. Overall heating load reduction due to the storm windows was 13percent with the clear glass and 21percent with the low-e windows. Simple paybacks for the addition of the storm windows were 10 years for the clear glass and 4.5 years forthe low-e storm windows.

  14. Analytical stress modeling of high-energy laser windows: Application to fusion-cast calcium fluoride windows

    NASA Astrophysics Data System (ADS)

    Klein, Claude A.

    2005-08-01

    The performance of a laser-window material must be assessed not only in terms of its ability to transmit high-power beams without generating undue optical distortion but also in terms of the constraints imposed by stress-related failure modes. In operational use, the stress field images the superposition of stresses originating from the mechanical load created by the pressure differential and the thermal load created by the laser beam. Here, we provide the tools to carry out an analysis of both pressure- and beam-induced stresses, and illustrate the procedure in the context of assessing the performance of a "model" window made of fusion-cast CaF2. The analysis assumes (a) operation on a time scale such that lateral heat diffusion can be ignored, and (b) cylindrically symmetric Gaussian beam shapes, which permit straightforward calculations of stress distributions that should be representative of worst case situations. Pressure-induced stresses strongly depend on the window's aspect ratio, which suggests increasing the thickness to minimize the stress, but considerations relating to the optical performance require minimum allowable thicknesses based on a Weibull statistical analysis of the fracture probability. Beam-induced stresses are best evaluated in terms of (a) thickness-averaged radial and azimuthal stresses, which increase linearly with exposure time and depend on radial distances through the truncation parameter, and (b) across-the-thickness stress deviations relative to the average stress, which are caused by surface absorption and reach steady-state configurations on a time scale much shorter than the characteristic time for lateral heat transport. The average stress is always compressive and equibiaxial in the central region of the window, but its azimuthal component turns tensile in the rim region, thus threatening the structural integrity through brittle fracture. In addition, the coating-induced stress results in on-axis surface compressions that may

  15. NREL Electrochromic Window Research Wins Award

    ScienceCinema

    None

    2013-05-29

    Winners of the CO-LABS Governor's Award for High-Impact Research in Energy Efficiency, Dr. Satyen Deb at the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) discovered that a small electrical charge can change the opacity of tungsten oxide from clear to tinted. He, Dr. Dane Gillaspie, and their fellow scientists at NREL then applied this knowledge to develop and transfer the technologies required to construct an electrochromic window, which can switch between clear and heavily tinted states. Electrochromic windows allow natural light in while adding tint to reduce summer heat and glare, and going clear to allow sunlight through in the winter. Broad adaptation of these windows could reduce US total energy use by four percent and reduce building cooling loads by 20%, much of this during expensive peak hours. Windows based on these discoveries are now being installed worldwide.

  16. Opening a window on the universe

    NASA Astrophysics Data System (ADS)

    Dutson, Kate

    2015-04-01

    The Cherenkov Telescope Array will revolutionize ground-based gamma-ray astronomy, explains Kate Dutson, extending our electromagnetic window on to the universe to include the highest-energy photons ever detected.

  17. MANAGING LARGE DATABASES WITH CUSTOMIZED SAS WINDOWS

    EPA Science Inventory

    This paper discusses the principles of database management through customized windows using SAS/AF, particularly PROC BUILD, to invoke interactive and batch processing of data entry, editing, updating, automatic report generation, and custom report generation functions, including...

  18. Rugged spinel windows and optics for harsh environments

    NASA Astrophysics Data System (ADS)

    Bayya, Shyam; Villalobos, Guillermo; Kim, Woohong; Busse, Lynda; Sanghera, Jasbinder; Aggarwal, Ishwar

    2013-05-01

    Spinel is a rugged ceramic transparent from ultraviolet to midwave infrared (0.18 - 5.5 μm) wavelengths. It has the best transmission from 4-5 μm among the competing materials ALON and sapphire with comparable mechanical properties. We have developed low absorption loss spinel as an exit window aperture for High Energy Laser systems. We demonstrated that spinel possesses excellent thermo-optical characteristics required for the High Energy Laser systems and at the same time it can provide the necessary ruggedness desired for the realistic and harsh battlefield environment. We have demonstrated through testing that spinel can withstand very adverse conditions of rain, sand storms and salt fog conditions without any change in its optical performance. We have also developed rugged anti-reflective coatings and anti-reflective surface structures to maintain high optical transmission in adverse environment.

  19. Electrochromic sun control coverings for windows

    SciTech Connect

    Benson, D K; Tracy, C E

    1990-04-01

    The 2 billion square meters (m{sup 2}) of building windows in the United States cause a national energy drain almost as large as the energy supply of the Alaskan oil pipeline. Unlike the pipeline, the drain of energy through windows will continue well into the 21st century. A part of this energy drain is due to unwanted sun gain through windows. This is a problem throughout the country in commercial buildings because they generally require air conditioning even in cold climates. New commercial windows create an additional 1600 MW demand for peak electric power in the United States each year. Sun control films, widely used in new windows and as retrofits to old windows, help to mitigate this problem. However, conventional, static solar control films also block sunlight when it is wanted for warmth and daylighting. New electrochromic, switchable, sun-gain-control films now under development will provide more nearly optimal and automatic sun control for added comfort, decreased building operating expense, and greater energy saving. Switchable, electrochromic films can be deposited on polymers at high speeds by plasma enhanced chemical vapor deposition (PECVD) in a process that may be suitable for roll coating. This paper describes the electrochromic coatings and the PECVD processes, and speculates about their adaptability to high-speed roll coating. 8 refs., 3 figs.

  20. Windowed multipole for cross section Doppler broadening

    NASA Astrophysics Data System (ADS)

    Josey, C.; Ducru, P.; Forget, B.; Smith, K.

    2016-02-01

    This paper presents an in-depth analysis on the accuracy and performance of the windowed multipole Doppler broadening method. The basic theory behind cross section data is described, along with the basic multipole formalism followed by the approximations leading to windowed multipole method and the algorithm used to efficiently evaluate Doppler broadened cross sections. The method is tested by simulating the BEAVRS benchmark with a windowed multipole library composed of 70 nuclides. Accuracy of the method is demonstrated on a single assembly case where total neutron production rates and 238U capture rates compare within 0.1% to ACE format files at the same temperature. With regards to performance, clock cycle counts and cache misses were measured for single temperature ACE table lookup and for windowed multipole. The windowed multipole method was found to require 39.6% more clock cycles to evaluate, translating to a 7.9% performance loss overall. However, the algorithm has significantly better last-level cache performance, with 3 fewer misses per evaluation, or a 65% reduction in last-level misses. This is due to the small memory footprint of the windowed multipole method and better memory access pattern of the algorithm.

  1. Noise Transmission Characteristics of Damped Plexiglas Windows

    NASA Technical Reports Server (NTRS)

    Gibbs, Gary P.; Buehrle, Ralph D.; Klos, Jacob; Brown, Sherilyn A.

    2002-01-01

    Most general aviation aircraft utilize single layer plexiglas material for the windshield and side windows. Adding noise control treatments to transparent panels is a challenging problem. In this paper, damped plexiglas windows are evaluated for replacement of conventional windows in general aviation aircraft to reduce the structure-borne and airborne noise transmitted into the interior. In contrast to conventional solid windows, the damped plexiglas window panels are fabricated using two or three layers of plexiglas with transparent viscoelastic damping material sandwiched between the layers. Results from acoustic tests conducted in the NASA Langley Structural Acoustic Loads and Transmission (SALT) facility are used to compare different designs of the damped plexiglas panels with solid windows of the same nominal thickness. Comparisons of the solid and damped plexiglas panels show reductions in the radiated sound power of up to 8 dB at low frequency resonances and as large as 4.5 dB over a 4000 Hz bandwidth. The weight of the viscoelastic treatment was approximately 1% of the panel mass. Preliminary FEM/BEM modeling shows good agreement with experimental results for radiated sound power.

  2. Window size impact in human activity recognition.

    PubMed

    Banos, Oresti; Galvez, Juan-Manuel; Damas, Miguel; Pomares, Hector; Rojas, Ignacio

    2014-01-01

    Signal segmentation is a crucial stage in the activity recognition process; however, this has been rarely and vaguely characterized so far. Windowing approaches are normally used for segmentation, but no clear consensus exists on which window size should be preferably employed. In fact, most designs normally rely on figures used in previous works, but with no strict studies that support them. Intuitively, decreasing the window size allows for a faster activity detection, as well as reduced resources and energy needs. On the contrary, large data windows are normally considered for the recognition of complex activities. In this work, we present an extensive study to fairly characterize the windowing procedure, to determine its impact within the activity recognition process and to help clarify some of the habitual assumptions made during the recognition system design. To that end, some of the most widely used activity recognition procedures are evaluated for a wide range of window sizes and activities. From the evaluation, the interval 1-2 s proves to provide the best trade-off between recognition speed and accuracy. The study, specifically intended for on-body activity recognition systems, further provides designers with a set of guidelines devised to facilitate the system definition and configuration according to the particular application requirements and target activities. PMID:24721766

  3. Highly transparent light-harvesting window film.

    PubMed

    Cocilovo, Byron; Hashimura, Aki; Tweet, Douglas J; Voutsas, Tolis; Norwood, Robert A

    2015-10-20

    We have simulated unique textured window films that capture solar radiation without compromising the window's transparency by scattering infrared light toward photovoltaic strips located at the edges of the window. These films are ideal for powering electrochromic glass, which is difficult to install as each window requires its own power source. Our most promising design consists of an embedded array of 35° cones coated with a five-layer SiO2-Ag stack that was simulated to direct 1.4% of the incident light toward the edges and generate 1 W of power under a collimated 1000  W/m2 AM1.5G source at 60° and an average of 0.5 W over a full year when applied to a 1  m×1  m window. The internal visible transmittance of the window with the applied film is 95% at normal incidence, and remains above 85% for viewing angles up to 60°. The haze is 0.6% at normal incidence and 3.9% at 60°. PMID:26560389

  4. Window Size Impact in Human Activity Recognition

    PubMed Central

    Banos, Oresti; Galvez, Juan-Manuel; Damas, Miguel; Pomares, Hector; Rojas, Ignacio

    2014-01-01

    Signal segmentation is a crucial stage in the activity recognition process; however, this has been rarely and vaguely characterized so far. Windowing approaches are normally used for segmentation, but no clear consensus exists on which window size should be preferably employed. In fact, most designs normally rely on figures used in previous works, but with no strict studies that support them. Intuitively, decreasing the window size allows for a faster activity detection, as well as reduced resources and energy needs. On the contrary, large data windows are normally considered for the recognition of complex activities. In this work, we present an extensive study to fairly characterize the windowing procedure, to determine its impact within the activity recognition process and to help clarify some of the habitual assumptions made during the recognition system design. To that end, some of the most widely used activity recognition procedures are evaluated for a wide range of window sizes and activities. From the evaluation, the interval 1–2 s proves to provide the best trade-off between recognition speed and accuracy. The study, specifically intended for on-body activity recognition systems, further provides designers with a set of guidelines devised to facilitate the system definition and configuration according to the particular application requirements and target activities. PMID:24721766

  5. Dust adhesion on Viking lander camera window

    NASA Technical Reports Server (NTRS)

    Singh, J. J.

    1978-01-01

    Studies of dust impingement on a duplicate Viking Lander camera window indicated the possibility of window obscuration after several days of exposure even at low dust concentration levels. As a result the following corrective measures were recommended: (1) The clearance between the housing surface and the camera post should be eliminated by using an appropriately designed plastic skirt: (2) The three horizontal ledges below the window inside the cavity act as bases for pile-up of dust that slides down the window surface; they should be replaced by a single inclined plane down which the dust will slide and fall out on the ground: (3) Adhered dust on the window surface can be removed by high pressure CO2 jets directed down against the window; the amount of CO2 gas needed for the entire mission can be carried in a 3 1/2-inch diameter sphere equipped with a remotely programable valve. These measures were incorporated in the design of the lander camera system. The continued high quality of photographs transmitted from the Viking spacecraft several months after landing attests to their effectiveness.

  6. Characterization of an all solid-state electrochromic window

    NASA Astrophysics Data System (ADS)

    Tonazzi, Juan C. L.; Valla, Bruno; Macedo, Marcelo A.; Baudry, Paul; Aegerter, Michel A.; Martins Rodrigues, Ana C.; Bulhoes, Luis O.

    1990-11-01

    Sol-gel cerium - titanium oxide layers present potential application as transparent counter-electrode (ion storage layer) in electrochromic windows and mirrors using lithium conducting electrolyte and W03 electrochromic coating. The precursor sol, prepared by mixing Ti(OPri)4 and Ce(N03)6 (NH4)2 in ethanol, is initially dark red and becomes transparent after a few days aging indicating the presence of Ce3 complexes. The layers have been obtained by dip coating technique and heat treated at 4509C during 15 minutes.They have been characterized by XRD, SIMS, optical absorption and electrochemical techniques; it is shown that the electrochemical reaction corresponds to a reversible insertion-extraction oflithium ions within a Ti02 amorphous film containing small Ce02 crystallites. At low sweep frequencies the process is controlled by a diffusion mechanism (DLi ~= 6.4 lOl2cm2/s at 259C). Characterizations of an all solid state electrochromic window/glass/JTO/ W03/ POE-Li N (502 CF3)2 1 Ti02 - Ce02 I ITO I glass I are also presented.

  7. Application of split window technique to TIMS data

    NASA Technical Reports Server (NTRS)

    Matsunaga, Tsuneo; Rokugawa, Shuichi; Ishii, Yoshinori

    1992-01-01

    Absorptions by the atmosphere in thermal infrared region are mainly due to water vapor, carbon dioxide, and ozone. As the content of water vapor in the atmosphere greatly changes according to weather conditions, it is important to know its amount between the sensor and the ground for atmospheric corrections of thermal Infrared Multispectral Scanner (TIMS) data (i.e. radiosonde). On the other hand, various atmospheric correction techniques were already developed for sea surface temperature estimations from satellites. Among such techniques, Split Window technique, now widely used for AVHRR (Advanced Very High Resolution Radiometer), uses no radiosonde or any kind of supplementary data but a difference between observed brightness temperatures in two channels for estimating atmospheric effects. Applications of Split Window technique to TIMS data are discussed because availability of atmospheric profile data is not clear when ASTER operates. After these theoretical discussions, the technique is experimentally applied to TIMS data at three ground targets and results are compared with atmospherically corrected data using LOWTRAN 7 with radiosonde data.

  8. BIPV-Powered Smart Windows Utilizing Photovoltaic and Electrochromic Devices

    PubMed Central

    Ma, Rong-Hua; Chen, Yu-Chia

    2012-01-01

    A BIPV-powered smart window comprising a building-integrated photovoltaic (BIPV) panel and an all-solid-state electrochromic (EC) stack is proposed. In the proposed device, the output voltage of the BIPV panel varies in accordance with the intensity of the incident light and is modulated in such a way as to generate the EC stack voltage required to maintain the indoor illuminance within a specified range. Two different EC stacks are fabricated and characterized, namely one stack comprising ITO/WO3/Ta2O5/ITO and one stack comprising ITO/WO3/lithium-polymer electrolyte/ITO. It is shown that of the two stacks, the ITO/WO3/lithium-polymer electrolyte/ITO stack has a larger absorptance (i.e., approximately 99% at a driving voltage of 3.5 V). The experimental results show that the smart window incorporating an ITO/WO3/lithium-polymer electrolyte/ITO stack with an electrolyte thickness of 1.0 μm provides an indoor illuminance range of 750–1,500 Lux under typical summertime conditions in Taiwan. PMID:22368474

  9. Manipulation of tunneling induced transparency windows and optical switching features in fivefold quantum dot molecules

    NASA Astrophysics Data System (ADS)

    Hamedi, H. R.; Reza Mehmannavaz, Mohammad

    2015-09-01

    Transient and steady-state behavior of the probe absorption in a multiple quantum dot (QD) molecule composed of five quantum dots molecules (with a center dot and four satellite dots) is explored with application in all-optical switching. We find that the absorption spectra of the light pulse can be efficiently modified via the effect of inter-dot tunnel couplings of QDs and incoherent pumping field. Results show that depending on the values of system parameters, at least one and at most four tunneling induced transparency (TIT) windows can be established in the multiple QD medium. We then investigate the dynamical behavior of the probe absorption-amplification as well as the optical switching in pulsed regime. By adjusting the incoherent pumping rate, the required switching time for changing the gain to the absorption or vice versa is then estimated approximately to be 20.7 nanosecond (ns), that is an appropriate time for such a QDM-based switch.

  10. Enhanced squeezing by absorption

    NASA Astrophysics Data System (ADS)

    Grünwald, P.; Vogel, W.

    2016-04-01

    Absorption is usually expected to be detrimental to quantum coherence effects. However, there have been few studies into the situation for complex absorption spectra. We consider the resonance fluorescence of excitons in a semiconductor quantum well. The creation of excitons requires absorption of the incoming pump-laser light. Thus, the absorption spectrum of the medium acts as a spectral filter for the emitted light. Surprisingly, absorption can even improve quantum effects, as is demonstrated for the squeezing of the resonance fluorescence of the quantum-well system. This effect can be explained by an improved phase matching due to absorption.

  11. Transforming the market for residential windows: design considerations for DOE's Efficient Window Collaborative

    SciTech Connect

    Eto, J.; Arasteh, D.; Selkowitz, S.

    1998-08-01

    Market adoption of recent, commercially available technological advances that improve the energy performance of windows will lead to immediate economic and energy savings benefits to the nation. This paper is a scoping study intended to inform the design of a major DOE initiative to accelerate market adoption of these windows in the residential sector. We describe the structure of the US residential window market and the interests of the various market players. We then briefly review five recent market transformation initiatives. Finally, we summarize our findings in a list of considerations we believe will be important for the DOE's initiative to transform the US residential window market.

  12. The Intestinal Absorption of Folates

    PubMed Central

    Visentin, Michele; Diop-Bove, Ndeye; Zhao, Rongbao; Goldman, I. David

    2014-01-01

    The properties of intestinal folate absorption were documented decades ago. However, it was only recently that the proton-coupled folate transporter (PCFT) was identified and its critical role in folate transport across the apical brush-border membrane of the proximal small intestine established by the loss-of-function mutations identified in the PCFT gene in subjects with hereditary folate malabsorption and, more recently, by the Pcft-null mouse. This article reviews the current understanding of the properties of PCFT-mediated transport and how they differ from those of the reduced folate carrier. Other processes that contribute to the transport of folates across the enterocyte, along with the contribution of the enterohepatic circulation, are considered. Important unresolved issues are addressed, including the mechanism of intestinal folate absorption in the absence of PCFT and regulation of PCFT gene expression. The impact of a variety of ions, organic molecules, and drugs on PCFT-mediated folate transport is described. PMID:24512081

  13. The intestinal absorption of folates.

    PubMed

    Visentin, Michele; Diop-Bove, Ndeye; Zhao, Rongbao; Goldman, I David

    2014-01-01

    The properties of intestinal folate absorption were documented decades ago. However, it was only recently that the proton-coupled folate transporter (PCFT) was identified and its critical role in folate transport across the apical brush-border membrane of the proximal small intestine established by the loss-of-function mutations identified in the PCFT gene in subjects with hereditary folate malabsorption and, more recently, by the Pcft-null mouse. This article reviews the current understanding of the properties of PCFT-mediated transport and how they differ from those of the reduced folate carrier. Other processes that contribute to the transport of folates across the enterocyte, along with the contribution of the enterohepatic circulation, are considered. Important unresolved issues are addressed, including the mechanism of intestinal folate absorption in the absence of PCFT and regulation of PCFT gene expression. The impact of a variety of ions, organic molecules, and drugs on PCFT-mediated folate transport is described. PMID:24512081

  14. Design, Fabrication and Testing of Multilayer Coated X-Ray Optics for the Water Window Imaging X-Ray Microscope

    NASA Technical Reports Server (NTRS)

    Spencer, Dwight C.

    1996-01-01

    Hoover et. al. built and tested two imaging Schwarzschild multilayer microscopes. These instruments were constructed as prototypes for the "Water Window Imaging X-Ray Microscope," which is a doubly reflecting, multilayer x-ray microscope configured to operate within the "water window." The "water window" is the narrow region of the x-ray spectrum between the K absorption edges of oxygen (lamda = 23.3 Angstroms) and of carbon (lamda = 43.62 Angstroms), where water is relatively highly transmissive and carbon is highly absorptive. This property of these materials, thus permits the use of high resolution multilayer x-ray microscopes for producing high contrast images of carbon-based structures within the aqueous physiological environments of living cells. We report the design, fabrication and testing of multilayer optics that operate in this regime.

  15. D-xylose absorption

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/003606.htm D-xylose absorption To use the sharing features on this page, please enable JavaScript. D-xylose absorption is a laboratory test to determine ...

  16. Window contamination on Expose-R

    NASA Astrophysics Data System (ADS)

    Demets, R.; Bertrand, M.; Bolkhovitinov, A.; Bryson, K.; Colas, C.; Cottin, H.; Dettmann, J.; Ehrenfreund, P.; Elsaesser, A.; Jaramillo, E.; Lebert, M.; van Papendrecht, G.; Pereira, C.; Rohr, T.; Saiagh, K.

    2015-01-01

    Expose is a multi-user instrument for astrobiological and astrochemical experiments in space. Installed at the outer surface of the International Space Station, it enables investigators to study the impact of the open space environment on biological and biochemical test samples. Two Expose missions have been completed so far, designated as Expose-E (Rabbow et al. 2012) and Expose-R (Rabbow et al. this issue). One of the space-unique environmental factors offered by Expose is full-spectrum, ultraviolet (UV)-rich electromagnetic radiation from the Sun. This paper describes and analyses how on Expose-R, access of the test samples to Solar radiation degraded during space exposure in an unpredicted way. Several windows in front of the Sun-exposed test samples acquired a brown shade, resulting in a reduced transparency in visible light, UV and vacuum UV (VUV). Post-flight investigations revealed the discolouration to be caused by a homogenous film of cross-linked organic polymers at the inside of the windows. The chemical signature varied per sample carrier. No such films were found on windows from sealed, pressurized compartments, or on windows that had been kept out of the Sun. This suggests that volatile compounds originating from the interior of the Expose facility were cross-linked and photo-fixed by Solar irradiation at the rear side of the windows. The origin of the volatiles was not fully identified; most probably there was a variety of sources involved including the biological test samples, adhesives, plastics and printed circuit boards. The outer surface of the windows (pointing into space) was chemically impacted as well, with a probable effect on the transparency in VUV. The reported analysis of the window contamination on Expose-R is expected to help the interpretation of the scientific results and offers possibilities to mitigate this problem on future missions - in particular Expose-R2, the direct successor of Expose-R.

  17. Infrared absorption cross sections of alternative CFCs

    NASA Technical Reports Server (NTRS)

    Clerbaux, Cathy; Colin, Reginald; Simon, Paul C.

    1994-01-01

    Absorption cross sections have obtained in the infrared atmospheric window, between 600 and 1500 cm(exp -1), for 10 alternative hydrohalocarbons: HCFC-22, HCFC-123, HCFC-124, HCFC-141b, HCFC-142b, HCFC-225ca, HCFC-225cb, HFC-125, HFC-134a, and HFC-152a. The measurements were made at three temperatures (287K, 270K and 253K) with a Fourier transform spectrometer operating at 0.03 cm(exp -1) apodized resolution. Integrated cross sections are also derived for use in radiative models to calculate the global warming potentials.

  18. Microelectronic device package with an integral window

    DOEpatents

    Peterson, Kenneth A.; Watson, Robert D.

    2002-01-01

    An apparatus for packaging of microelectronic devices, including an integral window. The microelectronic device can be a semiconductor chip, a CCD chip, a CMOS chip, a VCSEL chip, a laser diode, a MEMS device, or a IMEMS device. The package can include a cofired ceramic frame or body. The package can have an internal stepped structure made of one or more plates, with apertures, which are patterned with metallized conductive circuit traces. The microelectronic device can be flip-chip bonded on the plate to these traces, and oriented so that the light-sensitive side is optically accessible through the window. A cover lid can be attached to the opposite side of the package. The result is a compact, low-profile package, having an integral window that can be hermetically-sealed. The package body can be formed by low-temperature cofired ceramic (LTCC) or high-temperature cofired ceramic (HTCC) multilayer processes with the window being simultaneously joined (e.g. cofired) to the package body during LTCC or HTCC processing. Multiple chips can be located within a single package. The cover lid can include a window. The apparatus is particularly suited for packaging of MEMS devices, since the number of handling steps is greatly reduced, thereby reducing the potential for contamination.

  19. Hot Cell Window Shielding Analysis Using MCNP

    SciTech Connect

    Chad L. Pope; Wade W. Scates; J. Todd Taylor

    2009-05-01

    The Idaho National Laboratory Materials and Fuels Complex nuclear facilities are undergoing a documented safety analysis upgrade. In conjunction with the upgrade effort, shielding analysis of the Fuel Conditioning Facility (FCF) hot cell windows has been conducted. This paper describes the shielding analysis methodology. Each 4-ft thick window uses nine glass slabs, an oil film between the slabs, numerous steel plates, and packed lead wool. Operations in the hot cell center on used nuclear fuel (UNF) processing. Prior to the shielding analysis, shield testing with a gamma ray source was conducted, and the windows were found to be very effective gamma shields. Despite these results, because the glass contained significant amounts of lead and little neutron absorbing material, some doubt lingered regarding the effectiveness of the windows in neutron shielding situations, such as during an accidental criticality. MCNP was selected as an analysis tool because it could model complicated geometry, and it could track gamma and neutron radiation. A bounding criticality source was developed based on the composition of the UNF. Additionally, a bounding gamma source was developed based on the fission product content of the UNF. Modeling the windows required field inspections and detailed examination of drawings and material specifications. Consistent with the shield testing results, MCNP results demonstrated that the shielding was very effective with respect to gamma radiation, and in addition, the analysis demonstrated that the shielding was also very effective during an accidental criticality.

  20. "Broken windows" and the risk of gonorrhea.

    PubMed Central

    Cohen, D; Spear, S; Scribner, R; Kissinger, P; Mason, K; Wildgen, J

    2000-01-01

    OBJECTIVES: We examined the relationships between neighborhood conditions and gonorrhea. METHODS: We assessed 55 block groups by rating housing and street conditions. We mapped all cases of gonorrhea between 1994 and 1996 and calculated aggregated case rates by block group. We obtained public school inspection reports and assigned findings to the block groups served by the neighborhood schools. A "broken windows" index measured housing quality, abandoned cars, graffiti, trash, and public school deterioration. Using data from the 1990 census and 1995 updates, we determined the association between "broken windows," demographic characteristics, and gonorrhea rates. RESULTS: The broken windows index explained more of the variance in gonorrhea rates than did a poverty index measuring income, unemployment, and low education. In high-poverty neighborhoods, block groups with high broken windows scores had significantly higher gonorrhea rates than block groups with low broken windows scores (46.6 per 1000 vs 25.8 per 1000; P < .001). CONCLUSIONS: The robust association of deteriorated physical conditions of local neighborhoods with gonorrhea rates, independent of poverty, merits an intervention trial to test whether the environment has a causal role in influencing high-risk sexual behaviors. PMID:10667184

  1. Rugged sensor window materials for harsh environments

    NASA Astrophysics Data System (ADS)

    Bayya, Shyam; Villalobos, Guillermo; Kim, Woohong; Sanghera, Jasbinger; Hunt, Michael; Aggarwal, Ishwar D.

    2014-09-01

    There are several military or commercial systems operating in very harsh environments that require rugged windows. On some of these systems, windows become the single point of failure. These applications include sensor or imaging systems, high-energy laser weapons systems, submarine photonic masts, IR countermeasures and missiles. Based on the sea or land or air based platforms the window or dome on these systems must withstand wave slap, underwater or ground based explosions, or survive flight through heavy rain and sand storms while maintaining good optical transmission in the desired wavelength range. Some of these applications still use softer ZnS or fused silica windows because of lack of availability of rugged materials in shapes or sizes required. Sapphire, ALON and spinel are very rugged materials with significantly higher strengths compared to ZnS and fused silica. There have been recent developments in spinel, ALON and sapphire materials to fabricate in large sizes and conformal shapes. We have been developing spinel ceramics for several of these applications. We are also developing β-SiC as a transparent window material as it has higher hardness, strength, and toughness than sapphire, ALON and spinel. This paper gives a summary of our recent findings.

  2. X-Windows Socket Widget Class

    NASA Technical Reports Server (NTRS)

    Barry, Matthew R.

    2006-01-01

    The X-Windows Socket Widget Class ("Class" is used here in the object-oriented-programming sense of the word) was devised to simplify the task of implementing network connections for graphical-user-interface (GUI) computer programs. UNIX Transmission Control Protocol/Internet Protocol (TCP/IP) socket programming libraries require many method calls to configure, operate, and destroy sockets. Most X Windows GUI programs use widget sets or toolkits to facilitate management of complex objects. The widget standards facilitate construction of toolkits and application programs. The X-Windows Socket Widget Class encapsulates UNIX TCP/IP socket-management tasks within the framework of an X Windows widget. Using the widget framework, X Windows GUI programs can treat one or more network socket instances in the same manner as that of other graphical widgets, making it easier to program sockets. Wrapping ISP socket programming libraries inside a widget framework enables a programmer to treat a network interface as though it were a GUI.

  3. Damped Windows for Aircraft Interior Noise Control

    NASA Technical Reports Server (NTRS)

    Buehrle, Ralph D.; Klos, Jacob; Gibbs, Gary P.

    2004-01-01

    Windows are a significant path for structure-borne and air-borne noise transmission into aircraft. To improve the acoustical performance, damped windows were fabricated using two or three layers of plexiglas with transparent viscoelastic damping material sandwiched between the layers. In this paper, numerical and experimental results are used to evaluate the acoustic benefits of damped windows. Tests were performed in the Structural Acoustic Loads and Transmission Facility at NASA Langley Research Center to measure the transmission loss for diffuse acoustic excitation and radiated sound power for point force excitation. Comparisons between uniform and damped plexiglas windows showed increased transmission loss of 6 dB at the first natural frequency, 6 dB at coincidence, and 4.5 dB over a 50 to 4k Hz range. Radiated sound power was reduced up to 7 dB at the lower natural frequencies and 3.7 dB over a 1000 Hz bandwidth. Numerical models are presented for the prediction of radiated sound power for point force excitation and transmission loss for diffuse acoustic excitation. Radiated sound power and transmission loss predictions are in good agreement with experimental data. A parametric study is presented that evaluates the optimum configuration of the damped plexiglas windows for reducing the radiated sound power.

  4. A novel floating controlled release drug delivery system prepared by hot-melt extrusion.

    PubMed

    Vo, Anh Q; Feng, Xin; Morott, Joseph T; Pimparade, Manjeet B; Tiwari, Roshan V; Zhang, Feng; Repka, Michael A

    2016-01-01

    Floating dosage forms are an important formulation strategy for drugs with a narrow absorption window and low intestinal solubility, and for localized gastric treatment. Novel floating pellets were prepared using the hot-melt extrusion (HME) technology. Uniformly foamed strands were created by liquid injection pumping and screw configuration modification. The ammonio methacrylate copolymer (Eudragit® RSPO) foaming structure was formed by a liquid-vapor phase transition inside the strand upon die exiting resulting from the sudden decrease in external pressure, vaporizing the liquid ethanol and vacating the extruded material. This generated uniform vacuous regions in the extrudate. The pellets' internal structure was investigated using scanning electron microscopy (SEM). The formulation constituents' and processing parameters' effects on the drug release profiles, floating force, and the pellets' micromeritic properties were evaluated by design of experiments: all formulations showed zero lag time and excellent floating strength, indicating immediate-floating pellet formation. The pellets' drug release profiles were controlled by multiple independent variables at different time points (⩽ 24 h). Drug loading significantly affected drug release within the first hour, the hydroxypropyl methylcellulose (HPMC) content thereafter. Understanding the variables' effects on the formulations allows for the tailoring of this delivery system to obtain various drug release profiles. PMID:26643801

  5. Window type: 4x4 multipaned steel window flanked by 1x4 multipaned ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Window type: 4x4 multipaned steel window flanked by 1x4 multipaned steel, casements. Concrete stoop, entry overhang and pipe rail detail also illustrated. Building 36, facing northwest - Harbor Hills Housing Project, 26607 Western Avenue, Lomita, Los Angeles County, CA

  6. Window type: paired 2x4 multipaned steel windows flanked by 1x4 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Window type: paired 2x4 multipaned steel windows flanked by 1x4 multipaned steel casements, breaking building corner. Raised panel door front entry also illustrated. Ground floor detail Building 19, facing north - Harbor Hills Housing Project, 26607 Western Avenue, Lomita, Los Angeles County, CA

  7. Window type: paired 3x2 multipaned steel window flanked by 1x3 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Window type: paired 3x2 multipaned steel window flanked by 1x3 multipaned steel casements, breaking building corner. Broad overhanging eave also illustrated. Second story detail. Building 13, facing east - Harbor Hills Housing Project, 26607 Western Avenue, Lomita, Los Angeles County, CA

  8. The Moving Window Technique: A Window into Developmental Changes in Attention during Facial Emotion Recognition

    ERIC Educational Resources Information Center

    Birmingham, Elina; Meixner, Tamara; Iarocci, Grace; Kanan, Christopher; Smilek, Daniel; Tanaka, James W.

    2013-01-01

    The strategies children employ to selectively attend to different parts of the face may reflect important developmental changes in facial emotion recognition. Using the Moving Window Technique (MWT), children aged 5-12 years and adults ("N" = 129) explored faces with a mouse-controlled window in an emotion recognition task. An…

  9. 30 CFR 18.30 - Windows and lenses.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Windows and lenses. 18.30 Section 18.30 Mineral... § 18.30 Windows and lenses. (a) MSHA may waive testing of materials for windows or lenses except headlight lenses. When tested, material for windows or lenses shall meet the test requirements prescribed...

  10. 30 CFR 18.30 - Windows and lenses.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Windows and lenses. 18.30 Section 18.30 Mineral... § 18.30 Windows and lenses. (a) MSHA may waive testing of materials for windows or lenses except headlight lenses. When tested, material for windows or lenses shall meet the test requirements prescribed...

  11. 30 CFR 18.30 - Windows and lenses.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Windows and lenses. 18.30 Section 18.30 Mineral... § 18.30 Windows and lenses. (a) MSHA may waive testing of materials for windows or lenses except headlight lenses. When tested, material for windows or lenses shall meet the test requirements prescribed...

  12. 30 CFR 18.30 - Windows and lenses.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Windows and lenses. 18.30 Section 18.30 Mineral... § 18.30 Windows and lenses. (a) MSHA may waive testing of materials for windows or lenses except headlight lenses. When tested, material for windows or lenses shall meet the test requirements prescribed...

  13. 30 CFR 18.30 - Windows and lenses.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Windows and lenses. 18.30 Section 18.30 Mineral... § 18.30 Windows and lenses. (a) MSHA may waive testing of materials for windows or lenses except headlight lenses. When tested, material for windows or lenses shall meet the test requirements prescribed...

  14. Combined Pressure and Thermal Window System for Space Vehicles

    NASA Technical Reports Server (NTRS)

    Svartstrom, Kirk Nils (Inventor)

    2015-01-01

    A window system for a vehicle comprising a pressure and thermal window pane, a seal system, and a retainer system. The pressure and thermal window pane may be configured to provide desired pressure protection and desired thermal protection when exposed to an environment around the vehicle during operation of the vehicle. The pressure and thermal window pane may have a desired ductility. The seal system may be configured to contact the pressure and thermal window pane to seal the pressure and thermal window pane. The retainer system may be configured to hold the seal system and the pressure and thermal window pane.

  15. A simple hazemeter for window pollution assessment

    NASA Astrophysics Data System (ADS)

    Toy, M.; White, M. R.

    1980-03-01

    Window dirtiness is an obvious result of air pollution. The hazemeter described is a cheap and proven device for assessing two optical factors related to this. The value of measuring direct transmission loss is immediately apparent. The value of the haze or scattered light factor is not so obvious. It affects the total light passed through the window and was shown to have correlations with some of the psychological tests of which a brief mention has been made. The potential of this instrument can be extended to the design of more sophisticated analyses of the effect of pollution on windows; for example, the correlation of optical factors with deposit gauge and rain gauge readings, spectral distributions (say at twilight) and the effect on drivers of dirty windscreens.

  16. Apparatus for insulating windows and the like

    DOEpatents

    Mitchell, R.A.

    1984-06-19

    Apparatus for insulating window openings through walls and the like includes a thermal shutter, a rail for mounting the shutter adjacent to the window opening and a coupling for connecting the shutter to the rail. The thermal shutter includes an insulated panel adhered to frame members which surround the periphery of the panel. The frame members include a hard portion for providing the frame and a soft portion for providing a seal with that portion of the wall adjacent to the periphery of the opening. The coupling means is preferably integral with the attachment rail. According to a preferred embodiment, the coupling means includes a continuous hinge of reduced thickness. The thermal shutter can be permanently attached, hinged, bi-folded, or sliding with respect to the window and wall. A distribution method is to market the apparatus in kit'' form. 11 figs.

  17. Apparatus for insulating windows and the like

    DOEpatents

    Mitchell, Robert A.

    1984-01-01

    Apparatus for insulating window openings through walls and the like includes a thermal shutter, a rail for mounting the shutter adjacent to the window opening and a coupling for connecting the shutter to the rail. The thermal shutter includes an insulated panel adhered to frame members which surround the periphery of the panel. The frame members include a hard portion for providing the frame and a soft portion for providing a seal with that portion of the wall adjacent to the periphery of the opening. The coupling means is preferably integral with the attachment rail. According to a preferred embodiment, the coupling means includes a continuous hinge of reduced thickness. The thermal shutter can be permanently attached, hinged, bi-folded, or sliding with respect to the window and wall. A distribution method is to market the apparatus in "kit" form.

  18. Radcalc for Windows. Volume 2: Technical manual

    SciTech Connect

    Green, J.R.

    1995-09-27

    Radcalc for Windows is a user-friendly menu-driven Windows-compatible software program with applications in the transportation of radioactive materials. It calculates the radiolytic generation of hydrogen gas in the matrix of low-level and high-level radioactive waste using NRC-accepted methodology. It computes the quantity of a radionuclide and its associated products for a given period of time. In addition, the code categorizes shipment quantities as radioactive, Type A or Type B, limited quantity, low specific activity, highway route controlled, and fissile excepted using DOT definitions and methodologies, as outlined in 49 CFR Subchapter C. The code has undergone extensive testing and validation. Volume I is a User`s Guide, and Volume II is the Technical Manual for Radcalc for Windows

  19. High-Temperature Optical Window Design

    NASA Technical Reports Server (NTRS)

    Roeloffs, Norman; Taranto, Nick

    1995-01-01

    A high-temperature optical window is essential to the optical diagnostics of high-temperature combustion rigs. Laser Doppler velocimetry, schlieren photography, light sheet visualization, and laser-induced fluorescence spectroscopy are a few of the tests that require optically clear access to the combustor flow stream. A design was developed for a high-temperature window that could withstand the severe environment of the NASA Lewis 3200 F Lean Premixed Prevaporized (LPP) Flame Tube Test Rig. The development of this design was both time consuming and costly. This report documents the design process and the lessons learned, in an effort to reduce the cost of developing future designs for high-temperature optical windows.

  20. Fused silica windows for solar receiver applications

    NASA Astrophysics Data System (ADS)

    Hertel, Johannes; Uhlig, Ralf; Söhn, Matthias; Schenk, Christian; Helsch, Gundula; Bornhöft, Hansjörg

    2016-05-01

    A comprehensive study of optical and mechanical properties of quartz glass (fused silica) with regard to application in high temperature solar receivers is presented. The dependence of rupture strength on different surface conditions as well as high temperature is analyzed, focussing particularly on damage by devitrification and sandblasting. The influence of typical types of contamination in combination with thermal cycling on the optical properties of fused silica is determined. Cleaning methods are compared regarding effectiveness on contamination-induced degradation for samples with and without antireflective coating. The FEM-aided design of different types of receiver windows and their support structure is presented. A large-scale production process has been developed for producing fused silica dome shaped windows (pressurized window) up to a diameter of 816 mm. Prototypes were successfully pressure-tested in a test bench and certified according to the European Pressure Vessel Directive.

  1. Integral window hermetic fiber optic components

    SciTech Connect

    Dalton, R.D.; Kramer, D.P.; Massey, R.T.; Waker, D.A.

    1994-12-31

    In the fabrication of igniters, actuators, detonators, and other pyrotechnic devices to be activated by a laser beam, an integral optical glass window is formed by placing a preform in the structural member of the device and then melting the glass and sealing it in place by heating at a temperature between the ceramming temperature of the glass and the melting point of the metal, followed by rapid furnace cooling to avoid devitrification. No other sealing material is needed to achieve hermeticity. A preferred embodiment of this type of device is fabricated by allowing the molten glass to flow further and form a plano-convex lens integral with and at the bottom of the window. The lens functions to decrease the beam divergence caused by refraction of the laser light passing through the window when the device is fired by means of a laser beam.

  2. Integration Window Position Estimation in TR Receivers

    SciTech Connect

    Nekoogar, F; Dowla, F; Spiridon, A

    2005-03-15

    Transmitted-reference (TR) receivers avoid the stringent synchronization requirements that exist in conventional pulse detection schemes. However, the performance of such receivers is highly sensitive to precise timing acquisition and tracking as well as the length of their integration window. This window in TR receivers defines the limits of the finite integrator prior to the final decision making block. In this paper, we propose a novel technique that allows us to extract the timing information of the integration window very accurately in UWB-TR receivers in the presence of channel noise. The principles of the method are presented and the BER performance of a modified UWB-TR receiver is investigated by computer simulation. Our studies show that the proposed estimation technique adds value to the conventional TR receiver structure with modest increase in complexity.

  3. Single-agent parallel window search

    NASA Technical Reports Server (NTRS)

    Powley, Curt; Korf, Richard E.

    1991-01-01

    Parallel window search is applied to single-agent problems by having different processes simultaneously perform iterations of Iterative-Deepening-A(asterisk) (IDA-asterisk) on the same problem but with different cost thresholds. This approach is limited by the time to perform the goal iteration. To overcome this disadvantage, the authors consider node ordering. They discuss how global node ordering by minimum h among nodes with equal f = g + h values can reduce the time complexity of serial IDA-asterisk by reducing the time to perform the iterations prior to the goal iteration. Finally, the two ideas of parallel window search and node ordering are combined to eliminate the weaknesses of each approach while retaining the strengths. The resulting approach, called simply parallel window search, can be used to find a near-optimal solution quickly, improve the solution until it is optimal, and then finally guarantee optimality, depending on the amount of time available.

  4. Melt dispersion granules: formulation and evaluation to improve oral delivery of poorly soluble drugs - a case study with valsartan.

    PubMed

    Chella, Naveen; Tadikonda, Ramarao

    2015-06-01

    Solid dispersion (SD) technique is a promising strategy to improve the solubility and dissolution of BCS class II drugs. However, only few products are marketed till today based on SD technology due to poor flow properties and stability. The present work was intended to solve these problems by using combination approach, melt dispersion and surface adsorption technologies. The main aim of the present work is to improve the absorption in the stomach (at lower pH) where the absorption window exists for the drug by improving the dissolution, resulting in the enhancement of oral bioavailability of poorly soluble, weakly acidic drug with pH dependant solubility, i.e. valsartan. Melt dispersion granules were prepared in different ratios using different carriers (Gelucire 50/13, PEG 8000 and Pluronic F-68) and lactose as an adsorbent. Similarly, physical mixtures were also prepared at corresponding ratios. The prepared dispersion granules and physical mixtures were characterized by FTIR, DSC and in vitro dissolution studies. DSC studies revealed reduction in the crystallinity with a possibility of presence of amorphous character of drug in the dispersion granules. From dissolution studies, valsartan Gelucire dispersion (GSD4; 1:4 ratio) showed complete drug release in 30 min against the plain drug which showed only 11.31% of drug release in 30 min. Pharmacokinetic studies of optimized formulation in male Wistar rats showed 2.65-fold higher bioavailability and 1.47-fold higher Cmax compared to pure drug. The melt dispersion technology has the potential to improve dissolution and the bioavailability of BCS class II drugs. PMID:24796274

  5. Solar optical materials for innovative window design

    SciTech Connect

    Lampert, C.M.

    1982-08-01

    New and innovative optical materials and coatings can greatly improve the efficiency of window energy systems. These potential materials and coatings increase energy efficiency by reducing radiative losses in the infrared, or reducing visible reflection losses or controlling overheating due to solar gain. Current progress in heat mirror coatings for glass and polymeric substrates is presented. Highly doped semiconducting oxides and metal/dielectric interference coatings are reviewed. Physical and optical properties are outlined for antireflection films and transparent aerogel insulation media. The potential for optical switching films as window elements includes discussions of electrochromic, photochromic and other physical switching processes.

  6. Error-Based Design Space Windowing

    NASA Technical Reports Server (NTRS)

    Papila, Melih; Papila, Nilay U.; Shyy, Wei; Haftka, Raphael T.; Fitz-Coy, Norman

    2002-01-01

    Windowing of design space is considered in order to reduce the bias errors due to low-order polynomial response surfaces (RS). Standard design space windowing (DSW) uses a region of interest by setting a requirement on response level and checks it by a global RS predictions over the design space. This approach, however, is vulnerable since RS modeling errors may lead to the wrong region to zoom on. The approach is modified by introducing an eigenvalue error measure based on point-to-point mean squared error criterion. Two examples are presented to demonstrate the benefit of the error-based DSW.

  7. Window for radiation detectors and the like

    DOEpatents

    Sparks, C.J. Jr.; Ogle, J.C.

    1975-10-28

    An improved x- and gamma-radiation and particle transparent window for the environment-controlling enclosure of various types of radiation and particle detectors is provided by a special graphite foil of a thickness of from about 0.1 to 1 mil. The graphite must have very parallel hexagonal planes with a mosaic spread no greater than 5$sup 0$ to have the necessary strength in thin sections to support one atmosphere or more of pressure. Such graphite is formed by hot- pressing and annealing pyrolytically deposited graphite and thereafter stripping off layers of sufficient thickness to form the window.

  8. The window of opportunity: a relevant concept for axial spondyloarthritis

    PubMed Central

    2014-01-01

    The window of opportunity is a concept critical to rheumatoid arthritis treatment. Early treatment changes the outcome of rheumatoid arthritis treatment, in that response rates are higher with earlier disease-modifying anti-rheumatic drug treatment and damage is substantially reduced. Axial spondyloarthritis is an inflammatory axial disease encompassing both nonradiographic axial spondyloarthritis and established ankylosing spondylitis. In axial spondyloarthritis, studies of magnetic resonance imaging as well as tumor necrosis factor inhibitor treatment and withdrawal studies all suggest that early effective suppression of inflammation has the potential to reduce radiographic damage. This potential would suggest that the concept of a window of opportunity is relevant not only to rheumatoid arthritis but also to axial spondyloarthritis. The challenge now remains to identify high-risk patients early and to commence treatment without delay. Developments in risk stratification include new classification criteria, identification of clinical risk factors, biomarkers, genetic associations, potential antibody associations and an ankylosing spondylitis-specific microbiome signature. Further research needs to focus on the evidence for early intervention and the early identification of high-risk individuals. PMID:25167369

  9. Interior and Exterior Low-E Storm Window Installation

    SciTech Connect

    Witters, Sarah

    2014-09-03

    Until recently, energy-efficient window retrofit options have largely been limited to repair or replacement; leaving the homeowner to decide between affordability and deeper energy savings. A new and improved low-e storm window boasts a combination of curb appeal and energy efficiency, all for a fraction of the cost of window replacement. A recent whole-home experiment performed by PNNL suggests that attaching low-e storm windows can result in as much energy savings replacing the windows.

  10. Oral delivery of macromolecular drugs: Where we are after almost 100years of attempts.

    PubMed

    Moroz, Elena; Matoori, Simon; Leroux, Jean-Christophe

    2016-06-01

    Since the first attempt to administer insulin orally in humans more than 90years ago, the oral delivery of macromolecular drugs (>1000g/mol) has been rather disappointing. Although several clinical pilot studies have demonstrated that the oral absorption of macromolecules is possible, the bioavailability remains generally low and variable. This article reviews the formulations and biopharmaceutical aspects of orally administered biomacromolecules on the market and in clinical development for local and systemic delivery. The most successful approaches for systemic delivery often involve a combination of enteric coating, protease inhibitors and permeation enhancers in relatively high amounts. However, some of these excipients have induced local or systemic adverse reactions in preclinical and clinical studies, and long-term studies are often missing. Therefore, strategies aimed at increasing the oral absorption of macromolecular drugs should carefully take into account the benefit-risk ratio. In the absence of specific uptake pathways, small and potent peptides that are resistant to degradation and that present a large therapeutic window certainly represent the best candidates for systemic absorption. While we acknowledge the need for systemically delivering biomacromolecules, it is our opinion that the oral delivery to local gastrointestinal targets is currently more promising because of their accessibility and the lacking requirement for intestinal permeability enhancement. PMID:26826437

  11. Adverse antibiotic drug interactions.

    PubMed

    Bint, A J; Burtt, I

    1980-07-01

    There is enormous potential for drug interactions in patients who, today, often receive many drugs. Antibiotics are prominent amongst the groups of drugs commonly prescribed. Many interactions take place at the absorption stage. Antacids and antidiarrhoeal preparations, in particular, can delay and reduce the absorption of antibiotics such as tetracyclines and clindamycin, by combining with them in the gastrointestinal tract to form chelates or complexes. Other drugs can affect gastric motility, which in turn often controls the rate at which antibiotics are absorbed. Some broad spectrum antibiotics can alter the bacterial flora of the gut which may be related to malabsorption states. The potentiation of toxic side effects of one drug by another is a common type of interaction. Antibiotics which are implicated in this type of interaction are those which themselves possess some toxicity such as aminoglycosides, some cephalosporins, tetracyclines and colistin. Some of the most important adverse interactions with antibiotics are those which involve other drugs which have a low toxicity/efficacy ratio. These include anticoagulants such as warfarin, anticonvulsants such as phenytoin and phenobarbitone and oral antidiabetic drugs like tolbutamide. Risk of interaction arises when the metabolism of these drugs is inhibited by liver microsomal enzyme inhibitors such as some sulphonamides and chloramphenicol, or is enhanced by enzyme inducers such as rifampicin. PMID:6995091

  12. Aberration and boresight error correction for conformal aircraft windows using the inner window surface and tilted fixed correctors.

    PubMed

    Zhao, Chunzhu; Cui, Qingfeng; Mao, Shan

    2016-04-01

    A static solution to aberrations and boresight error for tilted conformal aircraft windows at different look angles is reported. The solution uses the inner window surface to correct the window aberrations at a 0° look angle and uses fixed correctors behind the window to correct the residual window aberrations at other look angles. Then, the boresight error for the window at different look angles is corrected by tilting the fixed correctors. The principle of the solution is discussed, and a design example shows that the solution is effective in correcting the aberrations and boresight error for a tilted conformal aircraft window at different look angles. PMID:27139665

  13. Design and analysis of a water window imaging x-ray microscope

    NASA Astrophysics Data System (ADS)

    Hoover, Richard B.; Baker, Phillip C.; Shealy, David L.; Brinkley, B. R.; Walker, Arthur B.; Barbee, Troy W.

    1991-06-01

    The authors have theoretically designed and analyzed the optical components and mechanical structures for an imaging x-ray microscope which will be configured to operate in the water window. This instrument affords new and noninvasive strategies for examining living tumor cells without the use of dyes, stains or other exogenous chemicals, which can produce limiting artifacts. The Water Window Imaging X-Ray Microscope is based on doubly reflecting, normal incidence multilayer optical technology, such as has been previously employed in telescopes for high resolution x-ray imaging of the sun. Multilayer coatings have now been fabricated with near theoretical reflectivities and perfect bandpass matching for the new rocket-borne solar observatory, the Multi-Spectral Solar Telescope Array (MSSTA). These telescopes employ multilayer mirror substrates with sub-angstrom (rms) smoothness which are made possible by Advanced Flow Polishing. Recent developments in multilayer coating technology and Advanced Flow Polishing methods used with Zerodur and Hemlite grade sapphire have paved the way for the development of the Water Window Imaging X-Ray Microscope. In this narrow water window wavelength regime of the x-ray spectrum, which lies between the K absorption edges of oxygen (23.3 $ANS) and of carbon (43.62 $ANS), water is relatively highly transmissive and carbon is highly absorptive. This principle allows the Water Window Imaging X-Ray Microscope to delineate, with high resolution and high contrast, carbon-based structures in the aqueous physiological environments found within living cells. The theoretical design and analysis of the microscope optical and mechanical components are described and the fabrication effort underway for the development of this new optical instrument, which should improve diagnosis and greatly benefit experimental studies of tumor cell biology, is discussed.

  14. No effect of food intake on clobazam absorption.

    PubMed Central

    Cenraud, B; Guyot, M; Levy, R H; Brachet-Liermain, A; Morselli, P L; Moreland, T A; Loiseau, P

    1983-01-01

    The kinetics of clobazam taken 3 h before, during, and 3 h after a standard hospital meal were studied in six healthy volunteers. Peak plasma levels were significantly lower when the drug was taken with or after meals suggesting that the rate of absorption was reduced by food. The mean area under the concentration vs time curve was not affected by the time of drug administration indicating that the meal had no effect upon the extent of absorption. PMID:6661360

  15. Time-dependent oral absorption models

    NASA Technical Reports Server (NTRS)

    Higaki, K.; Yamashita, S.; Amidon, G. L.

    2001-01-01

    The plasma concentration-time profiles following oral administration of drugs are often irregular and cannot be interpreted easily with conventional models based on first- or zero-order absorption kinetics and lag time. Six new models were developed using a time-dependent absorption rate coefficient, ka(t), wherein the time dependency was varied to account for the dynamic processes such as changes in fluid absorption or secretion, in absorption surface area, and in motility with time, in the gastrointestinal tract. In the present study, the plasma concentration profiles of propranolol obtained in human subjects following oral dosing were analyzed using the newly derived models based on mass balance and compared with the conventional models. Nonlinear regression analysis indicated that the conventional compartment model including lag time (CLAG model) could not predict the rapid initial increase in plasma concentration after dosing and the predicted Cmax values were much lower than that observed. On the other hand, all models with the time-dependent absorption rate coefficient, ka(t), were superior to the CLAG model in predicting plasma concentration profiles. Based on Akaike's Information Criterion (AIC), the fluid absorption model without lag time (FA model) exhibited the best overall fit to the data. The two-phase model including lag time, TPLAG model was also found to be a good model judging from the values of sum of squares. This model also described the irregular profiles of plasma concentration with time and frequently predicted Cmax values satisfactorily. A comparison of the absorption rate profiles also suggested that the TPLAG model is better at prediction of irregular absorption kinetics than the FA model. In conclusion, the incorporation of a time-dependent absorption rate coefficient ka(t) allows the prediction of nonlinear absorption characteristics in a more reliable manner.

  16. Improved Performance of Energy Window Ratio Criteria Obtained Using Multiple Windows at Radiation Portal Monitoring Sites

    SciTech Connect

    Weier, Dennis R.; Lopresti, Charles A.; Ely, James H.; Bates, Derrick J.; Kouzes, Richard T.

    2006-06-07

    Radiation portal monitors are being used to detect radioactive target materials in vehicles transporting cargo. As vehicles pass through the portal monitors, they generate count profiles over time that can be compared to the average panel background counts obtained just prior to the time the vehicle entered the area of the monitors. Pacific Northwest National Laboratory, in support of U.S. Customs and Border Protection (CBP) and U.S. Domestic Nuclear Detection Office (DNDO) under the U.S. Department of Homeland Security (DHS), has accumulated considerable data regarding such background radiation and vehicle profiles from portal installations. Energy window criteria have been shown to increase sensitivity to certain types of target radioactive sources while also controlling to a manageable level the rate of false or nuisance alarms. First generation equipment had only two-window capability, and while energy windowing for such systems was shown to be useful for detecting certain types of sources, it was subsequently found that improved performance could be obtained with more windows. Second generation equipment instead has more windows and can thus support additional energy window criteria which can be shown to be sensitive to a wider set of target sources. Detection likelihoods are generated for various sources and energy window criteria, as well as for gross count decision criteria, based on computer simulated injections of sources into archived vehicle profiles. (PIET-43741-TM-534)

  17. Percutaneous absorption in diseased skin: an overview.

    PubMed

    Chiang, Audris; Tudela, Emilie; Maibach, Howard I

    2012-08-01

    The stratum corneum's (SC) functions include protection from external hazardous environments, prevention of water loss and regulation of body temperature. While intact skin absorption studies are abundant, studies on compromised skin permeability are less common, although products are often used to treat affected skin. We reviewed literature on percutaneous absorption through abnormal skin models. Tape stripping is used to disrupt water barrier function. Studies demonstrated that physicochemical properties influence the stripping effect: water-soluble drugs are more affected. Abrasion did not affect absorption as much. Freezing is commonly used to preserve skin. It does not seem to modify water absorption, but still increases the penetration of compounds. Comparatively, heating the skin consistently increased percutaneous absorption. Removing SC lipids may increase percutaneous absorption of drugs. Many organic solvents are employed to delipidize. Delipidization with chloroform-methanol increased hydrophilic compound permeability, but not lipophilic. Acetone pre-treatment enhanced hydrophilic compound penetration. More data is needed to determine influence on highly lipophilic compound penetration. Sodium lauryl sulfate (SLS) induces irritant dermatitis and is frequently used as a model. Studies revealed that SLS increases hydrophilic compound absorption, but not lipophilic. However, skin irritation with other chemicals increases lipophilic penetration as much as hydrophilic. Animal studies show that UV exposure increases percutaneous absorption whereas human studies do not. Human studies show increased penetration in psoriatic and atopic dermatitis skin. The data summarized here begin to characterize flux alteration associated with damaged skin. Understanding the degree of alteration requires interpretation of involved conditions and the enlarging of our database to a more complete physicochemical spectrum. PMID:22912973

  18. Inexpensive anti-fog coating for windows

    NASA Technical Reports Server (NTRS)

    Carmin, D. L., Jr.; Morrison, H. D.

    1971-01-01

    Coating applications include anti-fog protection for deep-sea diving equipment, fire protection helmets, and windows of vehicles used in hazardous environments. Basic coating composition includes liquid detergent, deionized water, and oxygen compatible fire-resistant oil. Composition prevents visor fogging under maximum metabolic load for 5 hours and longer.

  19. A simple image display application for windows.

    PubMed

    Conrad, G R

    1997-08-01

    The purpose of this project was to develop a simple application for displaying low-to-moderate resolution digital images under the Windows operating environment. The display of scintigraphic images was of special interest, and for this reason the program was designed to show sequences of images and to account for broad ranges of pixel values. In order to function under a variety of Windows versions, the program was developed using the 16-bit Microsoft C +2 compiler and targeted for Windows 3.1 enhanced. It was tested with Trionix images for nuclear medicine and Siemens for computed tomography (CT) and magnetic resonance (MR). The resulting application, called SID, successfully read Magnetom, Somatom, Trionix, and Interfile images of dimension 512 or less on Intel-based Windows PCs with 256 color SVGA-compatible (Super Video Graphics Adapters) video hardware. Early applications of the program included remote monitoring of image studies, resident review of teaching cases, review of research images, and preparation of educational materials. This article describes the features, operation, and potential applications of SID. PMID:9268906

  20. Polycrystal GaAs infrared windows

    NASA Astrophysics Data System (ADS)

    Wada, Hideo; Shibata, Ken-ichiro; Yamashita, Masashi; Nakayama, Shigeru; Fujii, Akihito

    2001-09-01

    There are difficult points such as lowering of the detection or recognition capability of some targets by aerodynamic heating with speedup of the aircraft and missile and restriction of the operation by the raindrop in rainfall time on the conventional ZnS infrared window application used for missile seeker and FLIR equipment. Therefore, in this study, the promising polycrystal GaAs which has low infrared radiations in high temperature was produced using HB method (Horizontal Boat method) and VG method (Vertical Boat method) as a new infrared window material expected the durability for rain erosion. As the result, 70mm2 windows by the HB method and 100mm diameter windows by VB method were realized. Moreover, their optical characteristics, mechanical properties and thermal shock durabilities were measured and they were confirmed to be about 56% in average transmittance in the wavelength of 10micrometers bands, 530~630kg/mm2 in their hardness and thermostable at 300 degree(s)C.

  1. Considerations When Upgrading and Renovating Window Systems

    ERIC Educational Resources Information Center

    Gille, Steve

    2010-01-01

    Today's educational facilities managers face many challenges. As stewards of their campus' physical assets, these professionals are charged with improving students' learning environments, saving money, and maintaining the historical and aesthetic integrity of their buildings. For schools and universities that have not replaced their windows in…

  2. Sliding, Insulating Window Panel Reduces Heat Loss.

    ERIC Educational Resources Information Center

    School Business Affairs, 1984

    1984-01-01

    A new sliding insulated panel reduces window heat loss up to 86 percent, and infiltration 60-90 percent, paying for itself in 3-9 years. This article discusses the panel's use and testing in the upper Midwest, reporting both technical characteristics and users' reactions. (MCG)

  3. Windows 8: What Educators Need to Know

    ERIC Educational Resources Information Center

    Vedder, Richard G.

    2012-01-01

    In October 2012, Microsoft will release the commercial version of its next operating system, presently called "Windows 8." This version represents a significant departure from the past. Microsoft wants this operating system to meet user needs regardless of physical platform (e.g., desktop, notebook, tablet, mobile phone). As part of this mission,…

  4. Schools Facing the Expiration of Windows XP

    ERIC Educational Resources Information Center

    Cavanagh, Sean

    2013-01-01

    Microsoft's plans to end support for Windows XP, believed to be the dominant computer operating system in K-12 education, could pose big technological and financial challenges for districts nationwide--issues that many school systems have yet to confront. The giant software company has made it clear for years that it plans to stop supporting XP…

  5. An acoustic window for sustainable buildings

    NASA Astrophysics Data System (ADS)

    Kang, Jian; Brocklesby, Martin; Li, Zhemin; Oldham, David J.

    2005-04-01

    Encouraging the use of natural ventilation is an important tendency in the green building movement, but opening windows can often cause noise problems. This research develops a window system which allows natural ventilation while reducing noise transmission. The core idea is to create a ventilation path by staggering two layers of glass and using micro-perforated absorbers (MPA) along the path created to reduce noise. The MPA are made from transparent materials so that daylighting is relatively unaffected. Starting with a brief introduction of the MPA theory and its application in ducts, the paper presents a series of numerical simulations using finite element method based software FEMLAB, and experiment results measured between a semi-anechoic chamber and a reverberation chamber. Performance in acoustics, ventilation and daylighting are all taken into account. A basic window configuration is first considered, studying the effectiveness of various window parameters. A number of strategic designs are then examined, including external hoods and louvers in the sound path. There is generally a good agreement between simulation and measurement, and the noise reduction can be as good as a single glazing, with air movement to achieve occupant comfort, rather than just for minimum air exchange. [Work supported by EPSRC.

  6. New Window into the Human Body

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Michael Vannier, MD, a former NASA engineer, recognized the similarity between NASA's computerized image processing technology and nuclear magnetic resonance. With technical assistance from Kennedy Space Center, he developed a computer program for Mallinckrodt Institute of Radiology enabling Nuclear Magnetic Resonance (NMR) to scan body tissue for earlier diagnoses. Dr. Vannier feels that "satellite imaging" has opened a new window into the human body.

  7. Club Drugs

    MedlinePlus

    ... Rohypnol, ketamine, as well as MDMA (ecstasy) and methamphetamine ( Drug Facts: Club Drugs , National Institute on Drug ... Club Drugs , National Institute on Drug Abuse, 2010). Methamphetamine is a powerfully addictive stimulant associated with serious ...

  8. Potassium emission absorption system. Topical report 12

    SciTech Connect

    Bauman, L.E.

    1995-04-01

    The Potassium Emission Absorption System is one of the advanced optical diagnostics developed at Mississippi State University to provide support for the demonstration of prototype-scale coal-fired combustion magnetohydrodynamic (MHD) electrical power generation. Intended for application in the upstream of an MHD flow, the system directly measures gas temperature and neutral potassium atom number density through spectroscopic emission absorption techniques. From these measurements the electron density can be inferred from a statistical equilibrium calculation and the electron conductivity in the MHD channel found by use of an electron mobility model. The instrument has been utilized for field test measurements on MHD facilities for almost a decade and has been proven to provide useful measurements as designed for MHD nozzle, channel, and diffuser test sections. The theory of the measurements, a system description, its capabilities, and field test measurement results are reported here. During the development and application of the instrument several technical issues arose which when addressed advanced the state of the art in emission absorption measurement. Studies of these issues are also reported here and include: two-wavelength measurements for particle-laden flows, potassium D-line far wing absorption coefficient, bias in emission absorption measurements arising from dirty windows and misalignments, non-coincident multiwavelength emission absorption sampling errors, and lineshape fitting for boundary layer flow profile information. Although developed for NLHD application, the instrument could be applied to any high temperature flow with a resonance line in the 300 to 800 nm range, for instance other types of flames, rocket plumes or low temperature plasmas.

  9. Sphere-cone-polynomial special window with good aberration characteristic

    NASA Astrophysics Data System (ADS)

    Wang, Chao; Zhang, Xin; Qu, He-Meng; Wang, Ling-Jie; Wang, Yu

    2013-07-01

    Optical windows with external surfaces shaped to satisfy operational environment needs are known as special windows. A novel special window, a sphere-cone-polynomial (SCP) window, is proposed. The formulas of this window shape are given. An SCP MgF2 window with a fineness ratio of 1.33 is designed as an example. The field-of-regard (FOR) angle is ±75°. From the window system simulation results obtained with the calculated fluid dynamics (CFD) and optical design software, we find that compared to the conventional window forms, the SCP shape can not only introduce relatively less drag in the airflow, but also have the minimal effect on imaging. So the SCP window optical system can achieve a high image quality across a super wide FOR without adding extra aberration correctors. The tolerance analysis results show that the optical performance can be maintained with a reasonable fabricating tolerance to manufacturing errors.

  10. Drug delivery systems.

    PubMed

    Robinson, D H; Mauger, J W

    1991-10-01

    New and emerging drug delivery systems for traditional drugs and the products of biotechnology are discussed, and the role of the pharmacist in ensuring the appropriate use of these systems is outlined. Advantages of advanced drug delivery systems over traditional systems are the ability to deliver a drug more selectively to a specific site; easier, more accurate, less frequent dosing; decreased variability in systemic drug concentrations; absorption that is more consistent with the site and mechanism of action; and reductions in toxic metabolites. Four basic strategies govern the mechanisms of advanced drug delivery: physical, chemical, biological, and mechanical. Oral drug delivery systems use natural and synthetic polymers to deliver the product to a specific region in the gastrointestinal tract in a timely manner that minimizes adverse effects and increases drug efficacy. Innovations in injectable and implantable delivery systems include emulsions, particulate delivery systems, micromolecular products and macromolecular drug adducts, and enzymatic-controlled delivery. Options for noninvasive drug delivery include the transdermal, respiratory, intranasal, ophthalmic, lymphatic, rectal, intravaginal, and intrauterine routes as well as topical application. Rapid growth is projected in the drug delivery systems market worldwide in the next five years. Genetic engineering has mandated the development of new strategies to deliver biotechnologically derived protein and peptide drugs and chemoimmunoconjugates. The role of the pharmacist in the era of advanced drug delivery systems will be broad based, including administering drugs, compounding, calculating dosages based on pharmacokinetic and pharmacodynamic monitoring, counseling, and research. The advent of advanced drug delivery systems offers pharmacists a new opportunity to assume an active role in patient care. PMID:1772110

  11. Drug-drug interactions between clopidogrel and novel cardiovascular drugs.

    PubMed

    Pelliccia, Francesco; Rollini, Fabiana; Marazzi, Giuseppe; Greco, Cesare; Gaudio, Carlo; Angiolillo, Dominick J

    2015-10-15

    The combination of aspirin and the thienopyridine clopidogrel is a cornerstone in the prevention of atherothrombotic events. These two agents act in concert to ameliorate the prothrombotic processes stimulated by plaque rupture and vessel injury complicating cardiovascular disease. Guidelines recommend the use of clopidogrel in patients with acute coronary syndromes and in those undergoing percutaneous coronary intervention, and the drug remains the most utilized P2Y12 receptor inhibitor despite the fact that newer antiplatelet agents are now available. In recent years, numerous studies have shown inconsistency in the efficacy of clopidogrel to prevent atherothrombotic events. Studies of platelet function testing have shown variability in the response to clopidogrel. One of the major reason for this phenomenon lies in the interaction between clopidogrel and other drugs that may affect clopidogrel absorption, metabolism, and ultimately its antiplatelet action. Importantly, these drug-drug interactions have prognostic implications, since patients with high on-treatment platelet reactivity associated with reduced clopidogrel metabolism have an increased risk of ischemia. Previous systematic reviews have focused on drug-drug interactions between clopidogrel and specific pharmacologic classes, such as proton pump inhibitors, calcium channel blockers, and statins. However, more recent pieces of scientific evidence show that clopidogrel may also interact with newer drugs that are now available for the treatment of cardiovascular patients. Accordingly, the aim of this review is to highlight and discuss recent data on drug-drug interactions between clopidogrel and third-generation proton pump inhibitors, pantoprazole and lansoprazole, statins, pitavastatin, and antianginal drug, ranolazine. PMID:26341013

  12. Convex optimization-based windowed Fourier filtering with multiple windows for wrapped-phase denoising.

    PubMed

    Yatabe, Kohei; Oikawa, Yasuhiro

    2016-06-10

    The windowed Fourier filtering (WFF), defined as a thresholding operation in the windowed Fourier transform (WFT) domain, is a successful method for denoising a phase map and analyzing a fringe pattern. However, it has some shortcomings, such as extremely high redundancy, which results in high computational cost, and difficulty in selecting an appropriate window size. In this paper, an extension of WFF for denoising a wrapped-phase map is proposed. It is formulated as a convex optimization problem using Gabor frames instead of WFT. Two Gabor frames with differently sized windows are used simultaneously so that the above-mentioned issues are resolved. In addition, a differential operator is combined with a Gabor frame in order to preserve discontinuity of the underlying phase map better. Some numerical experiments demonstrate that the proposed method is able to reconstruct a wrapped-phase map, even for a severely contaminated situation. PMID:27409020

  13. NOTE: Visible absorption spectra of radiation exposed SIRAD dosimeters

    NASA Astrophysics Data System (ADS)

    Butson, Martin J.; Cheung, Tsang; Yu, Peter K. N.

    2006-12-01

    SIRAD badge dosimeters are a new type of personal dosimeter designed to measure radiation exposure up to 200 R and give a visual qualitative measurement of exposure. This is performed using the active dosimeter window, which contains a radiochromic material amalgamated in the badge assembly. When irradiated, the badges active window turns blue, which can be matched against the given colour chart for a qualitative assessment of the exposure received. Measurements have been performed to analyse the absorption spectra of the active window, and results show that the window automatically turns a blue colour upon irradiation and produces two peaks in the absorption spectra located at 617 nm and 567 nm. When analysed with a common computer desktop scanner, the optical density response of the film to radiation exposure is non-linear but reproducible. The net OD of the film was 0.21 at 50 R exposure and 0.31 at 200 R exposure when irradiated with a 6 MV x-ray energy beam. When compared to the calibration colour strips at 6 MV x-ray energy the film's OD response matches relatively well within 3.5%. An approximate 8% reduction in measured OD to exposure was seen for 250 kVp x-rays compared to 6 MV x-rays. The film provides an adequate measurement and visually qualitative assessment of radiation exposure for levels in the range of 0 to 200 R.

  14. Photodetachment neutralizer development: Laser window design study: Volume 2, Window design details: Final report

    SciTech Connect

    Not Available

    1987-01-01

    During 1983, TRW conducted a photodetachment neutralizer development (PDN) - Laser Resonator study. The emphasis of this contract was to assess a technology base of the PDN concept. Three technology assessments were conducted: Mirror Technology assessments, Window Engineering Analysis/Technology assessment, and COIL medium modeling with emphasis on PDN issues. Based on the results of these technology assessments the follow-on contract was funded to develop a technology verification. Due to funding limitations this technology verification program was divided into two separate follow-on contracts. Under this follow-on contract, the following tasks were performed: Measure Attenuation Coefficient of 3M FC-104, FC-77, FC-43 with temperature and attenuation coefficient of sapphire, generate finite element/finite difference thermal/structural model of the HEX double window, determine thermal/structural response from the proposed operating conditions, develop option response data from the deflection/stress inputs, recommend design and operating parameters for demonstrator and operational HEX double window, generate Level 1 layouts and drawings of double paned demonstrator window and window mount/manifold, and generate preliminary layout drawings of shutter. Thermal and structural analyses were conducted for both the operational and demonstrator window heat exchanger (HEX) designs and operating conditions.

  15. Solar absorption surface panel

    DOEpatents

    Santala, Teuvo J.

    1978-01-01

    A composite metal of aluminum and nickel is used to form an economical solar absorption surface for a collector plate wherein an intermetallic compound of the aluminum and nickel provides a surface morphology with high absorptance and relatively low infrared emittance along with good durability.

  16. Novel high-pressure windows made of glass-like carbon for x-ray analysis

    NASA Astrophysics Data System (ADS)

    Testemale, Denis; Prat, Alain; Lahera, Eric; Hazemann, Jean-Louis

    2016-07-01

    Original high-pressure glass-like carbon windows developed for x-ray spectroscopy applications are presented. The scientific and technological background of this new technical development is exposed, in particular the limitations of our existing beryllium windows in the context of x-ray absorption spectroscopy (XAS) measurements of solutions with very low solute concentrations at hydrothermal conditions (0.1-200 MPa, 30-600 °C). The benefits of glass-like carbon are exposed, notably its non-crystalline character, the absence of impurities which has been verified by micro-fluorescence laboratory measurements, and its non-toxicity which makes its machining safer. Finite elements mechanical calculations and experimental pressure tests were conducted to determine the pressure limits of windows with two different geometries: cylindrical (thickness 0.5 mm) and inversed-dome shape (thickness 0.5 mm at the tip of the dome). The former break at 150 MPa and the latter show no sign of rupture at 400 MPa. Recent XAS measurements conducted with the new dome shaped windows are presented to show the advantages of the design that allow for the detection of very low concentrations in the transmission mode (down to 30 ppm) and the acquisition of fluorescence XAS spectra in diluted solutions at high pressure. Eventually the perspectives of this original development are discussed.

  17. Chalcogenide glass fibers: Optical window tailoring and suitability for bio-chemical sensing

    NASA Astrophysics Data System (ADS)

    Lucas, Pierre; Coleman, Garrett J.; Jiang, Shibin; Luo, Tao; Yang, Zhiyong

    2015-09-01

    Glassy materials based on chalcogen elements are becoming increasingly prominent in the development of advanced infrared sensors. In particular, infrared fibers constitute a desirable sensing platform due to their high sensitivity and versatile remote collection capabilities for in-situ detection. Tailoring the transparency window of an optical material to the vibrational signature of a target molecule is important for the design of infrared sensor, and particularly for fiber evanescent wave spectroscopy. Here we review the basic principles and recent developments in the fabrication of chalcogenide glass infrared fibers for application as bio-chemical sensors. We emphasize the challenges in designing materials that combine good rheological properties with chemical stability and sufficiently wide optical windows for bio-chemical sensing. The limitation in optical transparency due to higher order overtones of the amorphous network vibrations is established for this family of glasses. It is shown that glasses with wide optical window suffer from higher order overtone absorptions. Compositional engineering with heavy elements such as iodine is shown to widen the optical window but at the cost of lower chemical stability. The optical attenuations of various families of chalcogenide glass fibers are presented and weighed for their applications as chemical sensors. It is then shown that long-wave infrared fibers can be designed to optimize the collection of selective signal from bio-molecules such as cells and tissues. Issues of toxicity and mechanical resistance in the context of bio-sensing are also discussed.

  18. Effect of migraine attacks on paracetamol absorption.

    PubMed Central

    Tokola, R A; Neuvonen, P J

    1984-01-01

    The absorption of effervescent paracetamol (1000 mg) was investigated in nine female patients during a migraine attack and in the same patients when headache free. Migraine attack decreased (P less than 0.05) the areas under the serum paracetamol concentration-time curves (AUC) of 0-2 h, 0-4 h and 0-6 h and the peak serum concentration. The severity of nausea correlated significantly with the decrease in the AUC values. Our results support findings of delayed gastric emptying in migraine attacks. Both a delay and an impairment of drug absorption may follow. PMID:6529526

  19. WINDOW 4.0: Documentation of calculation procedures

    SciTech Connect

    Finlayson, E.U.; Arasteh, D.K.; Huizenga, C.; Rubin, M.D.; Reilly, M.S.

    1993-07-01

    WINDOW 4.0 is a publicly available IBM PC compatible computer program developed by the Building Technologies Group at the Lawrence Berkeley Laboratory for calculating the thermal and optical properties necessary for heat transfer analyses of fenestration products. This report explains the calculation methods used in WINDOW 4.0 and is meant as a tool for those interested in understanding the procedures contained in WINDOW 4.0. All the calculations are discussed in the International System of units (SI). WINDOW 4.0 is the latest in a series of programs released by the Lawrence Berkeley Laboratory. The WINDOW program has its roots in a paper detailing a method for calculating heat transfer through windows [Rubin, 1982]. WINDOW 4.0 replaces the widely used 3.1 version. Although WINDOW 4.0 is a major revision, many of the algorithms used in WINDOW 4.0 build upon those previously documented [Arasteh, 1989b], [Furler, 1991]. This report documents the calculations that are unchanged from WINDOW 3.1, as well as those calculations that are new to WINDOW 4.0. This report uses the organization of the WINDOW 4.0 program. Results displayed on a WINDOW 4.0 screen are discussed in a section describing that screen. In the conclusion the aspects of the calculation method currently slated for revision are discussed. A glossary of variables used throughout the report is found in Section 11.

  20. Petawatt laser absorption bounded

    PubMed Central

    Levy, Matthew C.; Wilks, Scott C.; Tabak, Max; Libby, Stephen B.; Baring, Matthew G.

    2014-01-01

    The interaction of petawatt (1015 W) lasers with solid matter forms the basis for advanced scientific applications such as table-top particle accelerators, ultrafast imaging systems and laser fusion. Key metrics for these applications relate to absorption, yet conditions in this regime are so nonlinear that it is often impossible to know the fraction of absorbed light f, and even the range of f is unknown. Here using a relativistic Rankine-Hugoniot-like analysis, we show for the first time that f exhibits a theoretical maximum and minimum. These bounds constrain nonlinear absorption mechanisms across the petawatt regime, forbidding high absorption values at low laser power and low absorption values at high laser power. For applications needing to circumvent the absorption bounds, these results will accelerate a shift from solid targets, towards structured and multilayer targets, and lead the development of new materials. PMID:24938656

  1. Petawatt laser absorption bounded

    NASA Astrophysics Data System (ADS)

    Levy, Matthew C.; Wilks, Scott C.; Tabak, Max; Libby, Stephen B.; Baring, Matthew G.

    2014-06-01

    The interaction of petawatt (1015 W) lasers with solid matter forms the basis for advanced scientific applications such as table-top particle accelerators, ultrafast imaging systems and laser fusion. Key metrics for these applications relate to absorption, yet conditions in this regime are so nonlinear that it is often impossible to know the fraction of absorbed light f, and even the range of f is unknown. Here using a relativistic Rankine-Hugoniot-like analysis, we show for the first time that f exhibits a theoretical maximum and minimum. These bounds constrain nonlinear absorption mechanisms across the petawatt regime, forbidding high absorption values at low laser power and low absorption values at high laser power. For applications needing to circumvent the absorption bounds, these results will accelerate a shift from solid targets, towards structured and multilayer targets, and lead the development of new materials.

  2. In Vivo Formation of Cubic Phase in Situ after Oral Administration of Cubic Phase Precursor Formulation Provides Long Duration Gastric Retention and Absorption for Poorly Water-Soluble Drugs.

    PubMed

    Pham, Anna C; Hong, Linda; Montagnat, Oliver; Nowell, Cameron J; Nguyen, Tri-Hung; Boyd, Ben J

    2016-01-01

    Lipid-based liquid crystalline systems based on the combination of digestible and nondigestible lipids have been proposed as potential sustained release delivery systems for oral delivery of poorly water-soluble drugs. The potential for cubic phase liquid crystal formation to induce dramatically extended gastric retention in vivo has been shown previously to strongly influence the resulting pharmacokinetics of incorporated drug. In vitro studies showing the in situ formation of cubic phase from a disordered precursor comprising a mixture of digestible and nondigestible lipids under enzymatic digestion have also recently been reported. Combining both concepts, here we show the potential for such systems to form in vivo, increasing gastric retention, and providing a sustained release effect for a model poorly water-soluble drug cinnarizine. A mixture of phytantriol and tributyrin at an 85:15 mass ratio, shown previously to form cubic phase under the influence of digestion, induced a similar pharmacokinetic profile to that in the absence of tributyrin, but completely different from tributyrin alone. The gastric retention of the formulation, assessed using micro-X-ray CT imaging, was also consistent with the pharmacokinetic behavior, where phytantriol alone and with 15% tributyrin was greater than that of tributyrin in the absence of phytantriol. Thus, the concept of precursor lipid systems that form cubic phase in situ during digestion in vivo has been demonstrated and opens new opportunities for sustained release of poorly water-soluble drugs. PMID:26567591

  3. Drugs and the Brain: An Introduction to Neuropharmacology. Pamphlet Series.

    ERIC Educational Resources Information Center

    Brick, John

    The thousands of different drugs on the market can be separated into two categories: drugs that affect behavior, called psychoactive drugs, and drugs that do not affect behavior. Drugs get into the body by mouth, inhalation into the lungs, by injection into a vein, muscle or under the skin, and by absorption through mucous membranes. Regardless of…

  4. 21 CFR 211.94 - Drug product containers and closures.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Drug product containers and closures. 211.94... Components and Drug Product Containers and Closures § 211.94 Drug product containers and closures. (a) Drug product containers and closures shall not be reactive, additive, or absorptive so as to alter the...

  5. Helicobacter pylori infection and drugs malabsorption

    PubMed Central

    Lahner, Edith; Virili, Camilla; Santaguida, Maria Giulia; Annibale, Bruno; Centanni, Marco

    2014-01-01

    Drug absorption represents an important factor affecting the efficacy of oral drug treatment. Gastric secretion and motility seem to be critical for drug absorption. A causal relationship between impaired absorption of orally administered drugs and Helicobacter pylori (H. pylori) infection has been proposed. Associations have been reported between poor bioavailability of l-thyroxine and l-dopa and H. pylori infection. According to the Maastricht Florence Consensus Report on the management of H. pylori infection, H. pylori treatment improves the bioavailability of both these drugs, whereas the direct clinical benefits to patients still await to be established. Less strong seems the association between H. pylori infection and other drugs malabsorption, such as delavirdine and ketoconazole. The exact mechanisms forming the basis of the relationship between H. pylori infection and impaired drugs absorption and/or bioavailability are not fully elucidated. H. pylori infection may trigger a chronic inflammation of the gastric mucosa, and impaired gastric acid secretion often follows. The reduction of acid secretion closely relates with the wideness and the severity of the damage and may affect drug absorption. This minireview focuses on the evidence of H. pylori infection associated with impaired drug absorption. PMID:25132749

  6. The role of the equilibrative and concentrative nucleoside transporters in the intestinal absorption of the nucleoside drug, ribavirin, in wild-type and Ent1(−/−) mice

    PubMed Central

    Moss, Aaron M.; Endres, Christopher J.; Ruiz-Garcia, Ana; Choi, Doo-Sup; Unadkat, Jashvant D.

    2012-01-01

    Ribavirin is frontline treatment for hepatitis C virus infection. To determine the role of nucleoside transporters in the intestinal absorption of orally administered ribavirin, we perfused the intestines of Ent1(−/−) and wild-type mice, in situ, with [3H] ribavirin (20, 200 and 5000 μM) in the presence and absence of sodium. The decrease in luminal ribavirin concentration over 30 minutes was measured at 5-minute intervals. Blood samples were collected approximately every 10 minutes. Ribavirin plus phosphorylated metabolite concentrations (hereafter referred to as ribavirin) were determined in tissue, blood and plasma by HPLC fractionation and scintillation counting. There was no significant difference between wild-type and Ent1(−/−) mice in intestinal loss of ribavirin at any ribavirin concentration studied. Perfusions without sodium drastically reduced the intestinal loss of ribavirin in both wild-type and Ent1(−/−) mice. After 20 μM ribavirin perfusions, Ent1(−/−) intestinal tissue contained 8-fold greater ribavirin than wild-type mice (p<0.01). Ribavirin concentrations in the wild-type intestinal tissue were 70-fold higher after 200 vs. 20 μM perfusions (p<0.001), indicating saturation of intestinal ribavirin efflux and possibly other processes as well. Ribavirin plasma concentrations were significantly higher in wild-type mice (2.7-fold) vs. Ent1(−/−) mice at 30 minutes after the 20 μM perfusion (p<0.01). These results suggest that, at lower intestinal concentrations of ribavirin, concentrative and equilibrative nucleoside transporters are important in the intestinal absorption of ribavirin. At higher intestinal concentrations, these transporters are saturated and other processes in the intestine (transport and/or metabolism) play an important role in the absorption of ribavirin. PMID:22812541

  7. Drug allergies

    MedlinePlus

    Allergic reaction - drug (medication); Drug hypersensitivity; Medication hypersensitivity ... A drug allergy involves an immune response in the body that produces an allergic reaction to a medicine. The ...

  8. Continuous neural network with windowed Hebbian learning.

    PubMed

    Fotouhi, M; Heidari, M; Sharifitabar, M

    2015-06-01

    We introduce an extension of the classical neural field equation where the dynamics of the synaptic kernel satisfies the standard Hebbian type of learning (synaptic plasticity). Here, a continuous network in which changes in the weight kernel occurs in a specified time window is considered. A novelty of this model is that it admits synaptic weight decrease as well as the usual weight increase resulting from correlated activity. The resulting equation leads to a delay-type rate model for which the existence and stability of solutions such as the rest state, bumps, and traveling fronts are investigated. Some relations between the length of the time window and the bump width is derived. In addition, the effect of the delay parameter on the stability of solutions is shown. Also numerical simulations for solutions and their stability are presented. PMID:25677526

  9. A CLIPS/X-window interface

    NASA Technical Reports Server (NTRS)

    Pohl, Kym Jason

    1991-01-01

    The design and implementation of an interface between the C Language Integrated Production System (CLIPS) expert system development environment and the graphic user interface development tools of the X-Window system are described. The underlying basis of the CLIPS/X-Window is a client-server model in which multiple clients can attach to a single server that interprets, executes, and returns operation results, in response to client action requests. Implemented in an AIX (UNIX) operating system environment, the interface has been successfully applied in the development of graphics interfaces for production rule cooperating agents in a knowledge-based computer aided design (CAD) system. Initial findings suggest that the client-server model is particularly well suited to a distributed parallel processing operational mode in a networked workstation environment.

  10. Performance Criteria for Residential Zero Energy Windows

    SciTech Connect

    Arasteh, Dariush; Goudey, Howdy; Huang, Joe; Kohler, Christian; Mitchell, Robin

    2006-10-09

    This paper shows that the energy requirements for today's typical efficient window products (i.e. ENERGY STAR{trademark} products) are significant when compared to the needs of Zero Energy Homes (ZEHs). Through the use of whole house energy modeling, typical efficient products are evaluated in five US climates and compared against the requirements for ZEHs. Products which meet these needs are defined as a function of climate. In heating dominated climates, windows with U-factors of 0.10 Btu/hr-ft{sup 2}-F (0.57 W/m{sup 2}-K) will become energy neutral. In mixed heating/cooling climates a low U-factor is not as significant as the ability to modulate from high SHGCs (heating season) to low SHGCs (cooling season).

  11. OBSERVATIONAL WINDOW FUNCTIONS IN PLANET TRANSIT SURVEYS

    SciTech Connect

    Von Braun, Kaspar; Kane, Stephen R.; Ciardi, David R. E-mail: skane@ipac.caltech.edu

    2009-09-01

    The probability that an existing planetary transit is detectable in one's data is sensitively dependent upon the window function of the observations. We quantitatively characterize and provide visualizations of the dependence of this probability as a function of orbital period upon several observing strategy and astrophysical parameters, such as length of observing run, observing cadence, length of night, transit duration and depth, and the minimum number of sampled transits. The ability to detect a transit is directly related to the intrinsic noise of the observations. In our simulations of observational window functions, we explicitly address noncorrelated (Gaussian or white) noise and correlated (red) noise and discuss how these two noise components affect transit detectability in fundamentally different manners, especially for long periods and/or small transit depths. We furthermore discuss the consequence of competing effects on transit detectability, elaborate on measures of observing strategies, and examine the projected efficiency of different transit survey scenarios with respect to certain regions of parameter space.

  12. Shatter-Resistant, Flame-Resistant Window

    NASA Technical Reports Server (NTRS)

    Richardson, William R.; Walker, Ernie D.

    1989-01-01

    Combustion-chamber window combines properties of polycarbonate and sapphire. Inner layer of sapphire, withstands flame in chamber. Outer layer of polycarbonate tough but susceptible to weakening by flame and protected from flame by sapphire layer. Resists flames, shattering, and high pressure. Windows withstand 60 lb/in. to second power (414 kPa) in hydrostatic pressure vessel. Also survives leak test under internal pressure of 2 atm (0.2 MPa) of helium and external pressure of 10 to negative fifth power torr (1.3 mPa). Has transmission density of 0.08 to 0.11 in visible light. In contrast, unbonded layers have transmission density of 0.13 to 0.16.

  13. An expert system for window glazing design

    SciTech Connect

    Foss, R.V. ); Droste, D.H.

    1990-01-01

    An integrated expert system was developed to facilitate the design of window glass for structural strength, hydrostatic loads, sound attenuation, and solar control. The integrated software consists of a text-based interface, a rule-based expert system, and two neural networks. The text of a glazing design guide is linked by related topics and concepts. The software's design feature lets the user enter design parameters for the window choice via an interactive consultation in to a rule-based expert system that critiques the design. The technical aspects of the glass's structural strength are based primarily on linear methods published by the American Architectural Manufacturers Association Statistical correlations for the new nonlinear failure prediction for glass strength are used to automatically design for the minimum glass thickness required to withstand a specified load. Neural networks estimate values for sound attenuation and solar transmission characteristics from laboratory test data on selected glass constructions.

  14. Energy performance analysis of prototype electrochromic windows

    SciTech Connect

    Sullivan, R.; Rubin, M.; Selkowitz, S.

    1996-12-01

    This paper presents the results of a study investigating the energy performance of three newly developed prototype electrochromic devices. The DOE-2.1 E energy simulation program was used to analyze the annual cooling, lighting, and total electric energy use and peak demand as a function of window type and size. The authors simulated a prototypical commercial office building module located in the cooling-dominated locations of Phoenix, AZ and Miami, FL. Heating energy use was also studied in the heating-dominated location of Madison, WI. Daylight illuminance was used to control electrochromic state-switching. Two types of window systems were analyzed; i.e., the outer pane electrochromic glazing was combined with either a conventional low-E or a spectrally selective inner pane. The properties of the electrochromic glazings are based on measured data of new prototypes developed as part of a cooperative DOE-industry program. The results show the largest difference in annual electric energy performance between the different window types occurs in Phoenix and is about 6.5 kWh/m{sup 2} floor area (0.60 kWh/ft{sup 2}) which can represent a cost of about $.52/m{sup 2} ($.05/ft{sup 2}) using electricity costing $.08/kWh. In heating-dominated locations, the electrochromic should be maintained in its bleached state during the heating season to take advantage of beneficial solar heat gain which would reduce the amount of required heating. This also means that the electrochromic window with the largest solar heat gain coefficient is best.

  15. Diamond windows in a thermal shock environment

    SciTech Connect

    Klein, C.A.

    1995-12-31

    For most infrared-transmitting materials the primary cause of failure in a missile window/dome application can be attributed to brittle fracture induced by tensile stresses originating from instantaneous temperature gradients generated by aerodynamic heating. To describe the thermal shock I rely on the well known expression for the maximum stress experienced by a clamped plate (or a complete sphere), if there is a linear temperature variation across the thickness and both surfaces are free to expand.

  16. Diamondlike carbon protective coatings for optical windows

    NASA Technical Reports Server (NTRS)

    Swec, Diane M.; Mirtich, Michael J.

    1989-01-01

    Diamondlike carbon (DLC) films were deposited on infrared transmitting optical windows and were evaluated as protective coatings for these windows exposed to particle and rain erosion. The DLC films were deposited on zinc selenide (ZnSe) and zinc sulfide (ZnS) by three different ion beam methods: (1) sputter deposition from a carbon target using an 8-cm argon ion source; (2) direct deposition by a 30-cm hollow cathode ion source with hydrocarbon gas in argon; and (3) dual beam direct deposition by the 30-cm hollow cathode ion source and an 8-cm argon ion source. In an attempt to improve the adherence of the DLC films on ZnSc and ZnS, ion beam cleaning, ion implantation with helium and neon ions, or sputter deposition of a thin, ion beam intermediate coating was employed prior to deposition of the DLC film. The protection that the DLC films afforded the windows from particle and rain erosion was evaluated, along with the hydrogen content, adherence, intrinsic stress, and infrared transmittance of the films. Because of the elevated stress levels in the ion beam sputtered DLC films and in those ion beam deposited with butane, films thicker than 0.1 micron and with good adherence on ZnS and ZnSe could not be generated. An intermediate coating of germanium successfully allowed the DLC films to remain adherent to the optical windows and caused only negligible reduction in the specular transmittance of the ZnS and ZnSe at 10 microns.

  17. DETAIL VIEW, OXEYE WINDOW, SOUTH WALL OF SOUTH GARRET. THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL VIEW, OX-EYE WINDOW, SOUTH WALL OF SOUTH GARRET. THE MUNTIN PATTERN USED IN THIS WINDOW WAS REFERRED TO AS “GOTHIC” IN THE EIGHTEENTH CENTURY - The Woodlands, 4000 Woodlands Avenue, Philadelphia, Philadelphia County, PA

  18. Evaluation criteria and test methods for electrochromic windows

    SciTech Connect

    Czanderna, A.W. ); Lampert, C.M. )

    1990-07-01

    Report summarizes the test methods used for evaluating electrochromic (EC) windows, and summarizes what is known about degradation of their performance, and recommends methods and procedures for advancing EC windows for buildings applications. 77 refs., 13 figs., 6 tabs.

  19. 10. TYPICAL SIDE WALL WINDOW AND WATER TABLE. The water ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. TYPICAL SIDE WALL WINDOW AND WATER TABLE. The water table is an extension of the order base, and the lower torus breaks for ventilation, which applies to all windows. - Westminster Presbyterian Church, 273 Meeting Street, Charleston, Charleston County, SC

  20. WINDOW WITH ORIGINAL PANELED FOLDING SHUTTERS, SECOND FLOOR FRONT ROOM, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    WINDOW WITH ORIGINAL PANELED FOLDING SHUTTERS, SECOND FLOOR FRONT ROOM, LOOKING OUT WALNUT STREET (SOUTH). NOTE ALTERED LOWER SECTION MADE CA. 1840. Compare window in PA-1436 A-37 - Kid-Chandler House, 323 Walnut Street, Philadelphia, Philadelphia County, PA

  1. 35. DETAIL VIEW, WEST WINDOW IN WEST ELEVATION GABLE (NOTE: ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    35. DETAIL VIEW, WEST WINDOW IN WEST ELEVATION GABLE (NOTE: THE MOLDED STRINGCOURSE THAT PROJECTS FROM THE BASE OF THE FIRST FLOOR WINDOW ARCH AND VISIBLE WATERTABLE) - Kenworthy Hall, State Highway 14 (Greensboro Road), Marion, Perry County, AL

  2. Diamond technology for Endo-KEW seeker windows

    NASA Astrophysics Data System (ADS)

    Ravi, K. V.

    1992-05-01

    The attractions of low pressure synthesized diamond films and thick diamond slabs for Endo-KEW seeker window applications are presented. The use of diamond in two forms, as thin films in combination with silicon windows and as thick, free standing windows are discussed. A novel concept of internally cooled silicon/diamond windows that can withstand the rigors of high velocity, endo-atmospheric flight, that do not suffer from window irradiation resulting from aero-optic effects and have the potential for application as multispectral windows is discussed. The synthesis and processing aspects of thin diamond films and free standing diamond windows are presented with an analysis of the significant advantages of silicon and diamond for the fabrication of Endo-KEW seeker windows.

  3. DETAIL, EAST ELEVATION. THIS LUNETTE WINDOW POSITIONED IN A BLIND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL, EAST ELEVATION. THIS LUNETTE WINDOW POSITIONED IN A BLIND ARCH ECHOES A SIMILAR TREATMENT OF THE VENETIAN WINDOWS IN THE HOUSE - The Woodlands, 4000 Woodlands Avenue, Philadelphia, Philadelphia County, PA

  4. 12. TRIPLE WINDOW, FIRST FLOOR, SOUTH SIDE. Typical for all ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. TRIPLE WINDOW, FIRST FLOOR, SOUTH SIDE. Typical for all triple windows on first and second floors. Note single swing jib door - John Joyner Smith House, 400 Wilmington Street, Beaufort, Beaufort County, SC

  5. 23. CORNICES AND WINDOW ARCHITRAVES OF SOUTHEAST AND SOUTHWEST ROOMS, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    23. CORNICES AND WINDOW ARCHITRAVES OF SOUTHEAST AND SOUTHWEST ROOMS, FIRST FLOOR. Door architraves similar to window architraves. - John Joyner Smith House, 400 Wilmington Street, Beaufort, Beaufort County, SC

  6. Orthogonal sets of data windows constructed from trigonometric polynomials

    NASA Technical Reports Server (NTRS)

    Greenhall, C. A.

    1989-01-01

    Suboptimal, easily computable substitutes for the discrete prolate-spheroidal windows used by Thomson for spectral estimation are given. Trigonometric coefficients and energy leakages of the window polynomials are tabulated.

  7. 13. INTERIOR OF NORTHEAST PHOTO TOWER WITH WINDOW OPEN; ELECTRICAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. INTERIOR OF NORTHEAST PHOTO TOWER WITH WINDOW OPEN; ELECTRICAL POWER BOX BELOW WINDOW - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  8. Energy and Power Evaluation Program for Windows

    2000-06-27

    ENPEP for windows has its origins in the DOS version of the software, however, the Windows release is significantly modified and rather different in structure and capabilities from the older DOS version of ENPEP. ENPEP for Windows provides the user with a graphical interface for designing a comprehensive model of the energy system of a country or region. The BALANCE submodel processes a representative network of all energy production, conversion, transport, distribution, and utilization activitiesmore » in a country (or region) as well as the flows of energy and fuels among these activities. The objective of the model is to simulate energy market and determine energy supply and demand balance over a long-term period of up to 75 years. The environmental aspect is also taken into account by calculating the emissions of various pollutants. In addition to the energy costs, the environmental costs are also calculated by the model. These costs can be used to affect the solution found by the market equilibrium algorithm. The main purpose of the software is to provide analytical capability and tools for the various analyses of energy and environmental systems, as well as for development of long-term energy strategy of a country or region.« less

  9. Microwave Plasma Window Theory and Experiments

    NASA Astrophysics Data System (ADS)

    McKelvey, Andrew; Zheng, Peng; Franzi, Matthew; Lau, Y. Y.; Gilgenbach, Ronald; Plasma, Pulsed Power,; Microwave Laboratory Team

    2011-10-01

    The microwave plasma window is an experiment designed to promote RF breakdown in a controlled vacuum-gas environment using a DC bias. Experimental data has shown that this DC bias will significantly reduce the RF power required to yield breakdown, a feature also shown in recent simulation. The cross-polarized conducting array is biased at (100's V) DC on the surface of a Lucite vacuum window. Microwave power is supplied to the window's surface by a single 1-kW magnetron operating at 2.45 GHz CW. The goal of this project is to establish controllable characteristics relating vacuum pressure, DC bias, RF power required for surface breakdown, as well as RF transmission after the formation of plasma. Experimental data will be compared with multipactor susceptibility curves generated using a Monte Carlo simulation which incorporates an applied DC bias and finite pressures of air and argon. Research supported by an AFOSR grant on the Basic Physics of Distributed Plasma Discharge, AFRL, L-3 Communications, and Northrop Grumman.

  10. A review of electrochromic window performance factors

    SciTech Connect

    Selkowitz, S.E.; Rubin, M.; Lee, E.S.; Sullivan, R.; Finlayson, E.; Hopkins, D.

    1994-04-01

    The performance factors which will influence the market acceptance of electrochromic windows are reviewed. A set of data representing the optical properties of existing and foreseeable electrochromic window devices was generated. The issue of reflective versus absorbing electrochromics was explored. This data was used in the DOE 2.1 building energy model to calculate the expected energy savings compared to conventional glazings. The effects of several different control strategies were tested. Significant energy and peak electric demand benefits were obtained for some electrochromic types. Use of predictive control algorithms to optimize cooling control may result in greater energy savings. Initial economic results considering annual savings, cooling equipment cost savings, and electrochromic window costs are presented. Calculations of thermal and visual comfort show additional benefits from electrochromics but more work is needed to quantify their importance. The design freedom and aesthetic possibilities of these dynamic glazings should provide additional market benefits, but their impact is difficult to assess at this time. Ultimately, a full assessment of the market viability of electrochromics must consider the impacts of all of these issues.

  11. Flexible solid-state photoelectrochromic windows

    SciTech Connect

    Pichot, F.; Ferrere, S.; Pitts, R.J.; Gregg, B.A.

    1999-11-01

    Photoelectrochromic smart window technology is extended to include the use of flexible substrates and solid-state electrolytes. This should facilitate their application as retrofit modifications of office windows, where, by blocking incoming solar irradiation, they could substantially lower air-conditioning costs. These devices are based on a dye-sensitized TiO{sub 2} electrode coupled with a 500 nm thick WO{sub 3} electrochromic counter electrode, separated by a cross-linked polymer electrolyte containing LiI. A novel method for preparing conducting nanoporous TiO{sub 2} films is described that allows for the construction of these devices on flexible organic substrates. Colloidal solutions of TiO{sub 2} free of surfactants were spin-coated onto indium-tin oxide coated polyester substrates, resulting in highly transparent films ranging from 100 nm to 1 {micro}m in thickness. Upon annealing at 100 C, these films were strongly adherent and displayed excellent photoconductivity as shown by their current-voltage characteristics. The devices typically transmit 75% of visible light in the bleached state. After a few minutes of exposure to white light (75 mW/cm{sup 2}), the windows turn dark blue, transmitting only 30% of visible light. They spontaneously bleach back to their initial noncolored state upon removal of the light source.

  12. Window Area and Development Drive Spatial Variation in Bird-Window Collisions in an Urban Landscape

    PubMed Central

    Hager, Stephen B.; Cosentino, Bradley J.; McKay, Kelly J.; Monson, Cathleen; Zuurdeeg, Walt; Blevins, Brian

    2013-01-01

    Collisions with windows are an important human-related threat to birds in urban landscapes. However, the proximate drivers of collisions are not well understood, and no study has examined spatial variation in mortality in an urban setting. We hypothesized that the number of fatalities at buildings varies with window area and habitat features that influence avian community structure. In 2010 we documented bird-window collisions (BWCs) and characterized avian community structure at 20 buildings in an urban landscape in northwestern Illinois, USA. For each building and season, we conducted 21 daily surveys for carcasses and nine point count surveys to estimate relative abundance, richness, and diversity. Our sampling design was informed by experimentally estimated carcass persistence times and detection probabilities. We used linear and generalized linear mixed models to evaluate how habitat features influenced community structure and how mortality was affected by window area and factors that correlated with community structure. The most-supported model was consistent for all community indices and included effects of season, development, and distance to vegetated lots. BWCs were related positively to window area and negatively to development. We documented mortalities for 16/72 (22%) species (34 total carcasses) recorded at buildings, and BWCs were greater for juveniles than adults. Based on the most-supported model of BWCs, the median number of annual predicted fatalities at study buildings was 3 (range = 0–52). These results suggest that patchily distributed environmental resources and levels of window area in buildings create spatial variation in BWCs within and among urban areas. Current mortality estimates place little emphasis on spatial variation, which precludes a fundamental understanding of the issue. To focus conservation efforts, we illustrate how knowledge of the structural and environmental factors that influence bird-window collisions can be used

  13. Quasar Absorption Studies

    NASA Technical Reports Server (NTRS)

    Mushotzky, Richard (Technical Monitor); Elvis, Martin

    2004-01-01

    The aim of the proposal is to investigate the absorption properties of a sample of inter-mediate redshift quasars. The main goals of the project are: Measure the redshift and the column density of the X-ray absorbers; test the correlation between absorption and redshift suggested by ROSAT and ASCA data; constrain the absorber ionization status and metallicity; constrain the absorber dust content and composition through the comparison between the amount of X-ray absorption and optical dust extinction. Unanticipated low energy cut-offs where discovered in ROSAT spectra of quasars and confirmed by ASCA, BeppoSAX and Chandra. In most cases it was not possible to constrain adequately the redshift of the absorber from the X-ray data alone. Two possibilities remain open: a) absorption at the quasar redshift; and b) intervening absorption. The evidences in favour of intrinsic absorption are all indirect. Sensitive XMM observations can discriminate between these different scenarios. If the absorption is at the quasar redshift we can study whether the quasar environment evolves with the Cosmic time.

  14. Drug allergies

    MedlinePlus

    Allergic reaction - drug (medication); Drug hypersensitivity; Medication hypersensitivity ... Adverse reactions to drugs are common. (adverse means unwanted or unexpected.) Almost any drug can cause an adverse reaction. Reactions range from irritating ...

  15. Drug Safety

    MedlinePlus

    ... over-the-counter drug. The FDA evaluates the safety of a drug by looking at Side effects ... clinical trials The FDA also monitors a drug's safety after approval. For you, drug safety means buying ...

  16. Club Drugs

    MedlinePlus

    ... uses. Other uses of these drugs are abuse. Club drugs are also sometimes used as "date rape" drugs, to make someone unable to say no to or fight back against sexual assault. Abusing these drugs can ...

  17. A Windowing Frequency Domain Adaptive Filter for Acoustic Echo Cancellation

    NASA Astrophysics Data System (ADS)

    Wu, Sheng; Qiu, Xiaojun

    This letter proposes a windowing frequency domain adaptive algorithm, which reuses the filtering error to apply window function in the filter updating symmetrically. By using a proper window function to reduce the negative influence of the spectral leakage, the proposed algorithm can significantly improve the performance of the acoustic echo cancellation for speech signals.

  18. 14 CFR 29.775 - Windshields and windows.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Windshields and windows. 29.775 Section 29.775 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Accommodations § 29.775 Windshields and windows. Windshields and windows must be made of material that will...

  19. 14 CFR 27.775 - Windshields and windows.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Windshields and windows. 27.775 Section 27.775 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... § 27.775 Windshields and windows. Windshields and windows must be made of material that will not...

  20. Nonuniform Effects of Reinstatement within the Time Window

    ERIC Educational Resources Information Center

    Galluccio, Llissa; Rovee-Collier, Carolyn

    2006-01-01

    A time window is a limited period after an event initially occurs in which additional information can be integrated with the memory of that event. It shuts when the memory is forgotten. The time window hypothesis holds that the impact of a manipulation at different points within the time window is nonuniform. In two operant conditioning…

  1. Reactively evaporated multilayer antireflection coatings for Ge optical window

    NASA Astrophysics Data System (ADS)

    Asghar, M. H.; Placido, F.; Naseem, S.

    2007-04-01

    Two multilayer antireflection (AR) coating configurations are designed, prepared and characterized. These AR coatings are designed for a 1 mm thick Ge optical window in the 3.25-5.25 µm band. Ta2O5 and TiO2 are used as high index materials along with SiO2 as low index material. Configuration 1 comprises nine alternating layers of SiO2 and Ta2O5, whereas configuration 2 comprises seven alternating layers of SiO2 and TiO2. Post-deposition annealing is also carried out in the temperature range 150-450 °C for 10 h. The prepared multilayered structures are characterized optically and structurally using a spectrophotometer, an atomic force microscope, x-ray diffraction and a scanning electron microscope. Optical characterization shows that multilayered structures have high absorption for as-deposited samples. A considerable improvement in the transmission profiles for the two multilayered configurations is observed at 350 °C with peak and average transmission for both the configurations exceeding 90%. The as-prepared samples show predominantly amorphous-like structure with pronounced peaks for configuration 2 only. Delamination (for configuration 1) and cracking (for configuration 2) of the multilayered structures are witnessed at an annealing temperature of 450 °C.

  2. Nanophotonics-enabled smart windows, buildings and wearables

    NASA Astrophysics Data System (ADS)

    Smith, Geoff; Gentle, Angus; Arnold, Matthew; Cortie, Michael

    2016-06-01

    Design and production of spectrally smart windows, walls, roofs and fabrics has a long history, which includes early examples of applied nanophotonics. Evolving nanoscience has a special role to play as it provides the means to improve the functionality of these everyday materials. Improvement in the quality of human experience in any location at any time of year is the goal. Energy savings, thermal and visual comfort indoors and outdoors, visual experience, air quality and better health are all made possible by materials, whose "smartness" is aimed at designed responses to environmental energy flows. The spectral and angle of incidence responses of these nanomaterials must thus take account of the spectral and directional aspects of solar energy and of atmospheric thermal radiation plus the visible and color sensitivity of the human eye. The structures required may use resonant absorption, multilayer stacks, optical anisotropy and scattering to achieve their functionality. These structures are, in turn, constructed out of particles, columns, ultrathin layers, voids, wires, pure and doped oxides, metals, polymers or transparent conductors (TCs). The need to cater for wavelengths stretching from 0.3 to 35 μm including ultraviolet-visible, near-infrared (IR) and thermal or Planck radiation, with a spectrally and directionally complex atmosphere, and both being dynamic, means that hierarchical and graded nanostructures often feature. Nature has evolved to deal with the same energy flows, so biomimicry is sometimes a useful guide.

  3. 21 CFR 862.2850 - Atomic absorption spectrophotometer for clinical use.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Atomic absorption spectrophotometer for clinical... Laboratory Instruments § 862.2850 Atomic absorption spectrophotometer for clinical use. (a) Identification. An atomic absorption spectrophotometer for clinical use is a device intended to identify and...

  4. 21 CFR 862.2850 - Atomic absorption spectrophotometer for clinical use.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Atomic absorption spectrophotometer for clinical... Laboratory Instruments § 862.2850 Atomic absorption spectrophotometer for clinical use. (a) Identification. An atomic absorption spectrophotometer for clinical use is a device intended to identify and...

  5. 21 CFR 862.2850 - Atomic absorption spectrophotometer for clinical use.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Atomic absorption spectrophotometer for clinical... Laboratory Instruments § 862.2850 Atomic absorption spectrophotometer for clinical use. (a) Identification. An atomic absorption spectrophotometer for clinical use is a device intended to identify and...

  6. 21 CFR 862.2850 - Atomic absorption spectrophotometer for clinical use.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Atomic absorption spectrophotometer for clinical... Laboratory Instruments § 862.2850 Atomic absorption spectrophotometer for clinical use. (a) Identification. An atomic absorption spectrophotometer for clinical use is a device intended to identify and...

  7. Compounds affecting cholesterol absorption

    NASA Technical Reports Server (NTRS)

    Hua, Duy H. (Inventor); Koo, Sung I. (Inventor); Noh, Sang K. (Inventor)

    2004-01-01

    A class of novel compounds is described for use in affecting lymphatic absorption of cholesterol. Compounds of particular interest are defined by Formula I: ##STR1## or a pharmaceutically acceptable salt thereof.

  8. Absorption heat pump system

    DOEpatents

    Grossman, Gershon

    1984-01-01

    The efficiency of an absorption heat pump system is improved by conducting liquid from a second stage evaporator thereof to an auxiliary heat exchanger positioned downstream of a primary heat exchanger in the desorber of the system.

  9. Absorption heat pump system

    DOEpatents

    Grossman, G.

    1982-06-16

    The efficiency of an absorption heat pump system is improved by conducting liquid from a second stage evaporator thereof to an auxiliary heat exchanger positioned downstream of a primary heat exchanger in the desorber of the system.

  10. Dipeptide absorption in man

    PubMed Central

    Hellier, M. D.; Holdsworth, C. D.; McColl, I.; Perrett, D.

    1972-01-01

    A quantitative perfusion method has been used to study intestinal absorption of two dipeptides—glycyl-glycine and glycyl-l-alanine—in normal subjects. In each case, the constituent amino acids were absorbed faster when presented as dipeptides than as free amino acids, suggesting intact dipeptide transport. During absorption constituent amino acids were measured within the lumen and it is suggested that these represent amino acids which have diffused back to the lumen after absorption as dipeptide. Portal blood analyses during absorption of a third dipeptide, glycyl-l-lysine, have shown that this dipeptide, known to be transported intact from the intestinal lumen, is hydrolysed to its constitutent amino acids before it reaches portal venous blood. PMID:4652039

  11. Record Multiphoton Absorption Cross-Sections by Dendrimer Organometalation.

    PubMed

    Simpson, Peter V; Watson, Laurance A; Barlow, Adam; Wang, Genmiao; Cifuentes, Marie P; Humphrey, Mark G

    2016-02-12

    Large increases in molecular two-photon absorption, the onset of measurable molecular three-photon absorption, and record molecular four-photon absorption in organic π-delocalizable frameworks are achieved by incorporation of bis(diphosphine)ruthenium units with alkynyl linkages. The resultant ruthenium alkynyl-containing dendrimers exhibit strong multiphoton absorption activity through the biological and telecommunications windows in the near-infrared region. The ligated ruthenium units significantly enhance solubility and introduce fully reversible redox switchability to the optical properties. Increasing the ruthenium content leads to substantial increases in multiphoton absorption properties without any loss of optical transparency. This significant improvement in multiphoton absorption performance by incorporation of the organometallic units into the organic π-framework is maintained when the relevant parameters are scaled by molecular weights or number of delocalizable π-electrons. The four-photon absorption cross-section of the most metal-rich dendrimer is an order of magnitude greater than the previous record value. PMID:26797727

  12. A Group Increment Scheme for Infrared Absorption Intensities of Greenhouse Gases

    NASA Technical Reports Server (NTRS)

    Kokkila, Sara I.; Bera, Partha P.; Francisco, Joseph S.; Lee, Timothy J.

    2012-01-01

    A molecule's absorption in the atmospheric infrared (IR) window (IRW) is an indicator of its efficiency as a greenhouse gas. A model for estimating the absorption of a fluorinated molecule within the IRW was developed to assess its radiative impact. This model will be useful in comparing different hydrofluorocarbons and hydrofluoroethers contribution to global warming. The absorption of radiation by greenhouse gases, in particular hydrofluoroethers and hydrofluorocarbons, was investigated using ab initio quantum mechanical methods. Least squares regression techniques were used to create a model based on this data. The placement and number of fluorines in the molecule were found to affect the absorption in the IR window and were incorporated into the model. Several group increment models are discussed. An additive model based on one-carbon groups is found to work satisfactorily in predicting the ab initio calculated vibrational intensities.

  13. Optical absorption measurement system

    DOEpatents

    Draggoo, Vaughn G.; Morton, Richard G.; Sawicki, Richard H.; Bissinger, Horst D.

    1989-01-01

    The system of the present invention contemplates a non-intrusive method for measuring the temperature rise of optical elements under high laser power optical loading to determine the absorption coefficient. The method comprises irradiating the optical element with a high average power laser beam, viewing the optical element with an infrared camera to determine the temperature across the optical element and calculating the absorption of the optical element from the temperature.

  14. Solar selective absorption coatings

    DOEpatents

    Mahoney, Alan R.; Reed, Scott T.; Ashley, Carol S.; Martinez, F. Edward

    2004-08-31

    A new class of solar selective absorption coatings are disclosed. These coatings comprise a structured metallic overlayer such that the overlayer has a sub-micron structure designed to efficiently absorb solar radiation, while retaining low thermal emissivity for infrared thermal radiation. A sol-gel layer protects the structured metallic overlayer from mechanical, thermal, and environmental degradation. Processes for producing such solar selective absorption coatings are also disclosed.

  15. Solar selective absorption coatings

    DOEpatents

    Mahoney, Alan R.; Reed, Scott T.; Ashley, Carol S.; Martinez, F. Edward

    2003-10-14

    A new class of solar selective absorption coatings are disclosed. These coatings comprise a structured metallic overlayer such that the overlayer has a sub-micron structure designed to efficiently absorb solar radiation, while retaining low thermal emissivity for infrared thermal radiation. A sol-gel layer protects the structured metallic overlayer from mechanical, thermal, and environmental degradation. Processes for producing such solar selective absorption coatings are also disclosed.

  16. Studying Titan's surface photometry in the 5 microns atmospheric window with the Cassini/VIMS instrument

    NASA Astrophysics Data System (ADS)

    Cornet, T.; Altobelli, N.; Sotin, C.; Le Mouelic, S.; Rodriguez, S.; Philippe, S.; Brown, R. H.; Barnes, J. W.; Buratti, B. J.; Baines, K. H.; Clark, R. N.; Nicholson, P. D.

    2014-12-01

    Due to the influence of methane gas and a thick aerosols haze in the atmosphere, Titan's surface is only visible in 7 spectral atmospheric windows centered at 0.93, 1.08, 1.27, 1.59, 2.01, 2.7-2.8 and 5 microns with the Cassini Visual and Infrared Mapping Spectrometer (VIMS). The 5 microns atmospheric window constitutes the only one being almost insensitive to the haze scattering and which presents only a reduced atmospheric absorption contribution to the signal recorded by the instrument. Despite these advantages leading to the almost direct view of the surface, the 5 microns window is also the noisiest spectral window of the entire VIMS spectrum (an effect highly dependent on the time exposure used for the observations), and it is not totally free from atmospheric contributions, enough to keep "artefacts" in mosaics of several thousands of cubes due to atmospheric and surface photometric effects amplified by the very heterogeneous viewing conditions between each Titan flyby. At first order, a lambertian surface photometry at 5 microns has been used as an initial parameter in order to estimate atmospheric opacity and surface photometry in all VIMS atmospheric windows and to determine the albedo of the surface, yet unknown, both using radiative transfer codes on single cubes or empirical techniques on global hyperspectral mosaics. Other studies suggested that Titan's surface photometry would not be uniquely lambertian but would also contain anisotropic lunar-like contributions. In the present work, we aim at constraining accurately the surface photometry of Titan and residual atmospheric absorption effects in this 5 microns window using a comprehensive study of relevant sites located at various latitudes. Those include bright and dark (dunes) terrains, 5-microns bright terrains (Hotei Regio and Tui Regio), the Huygens Landing Site and high latitudes polar lakes and seas. The VIMS 2004 to 2014 database, composed of more than 40,000 hyperspectral cubes acquired on

  17. Tomographic retrieval for scattered light limb measurements: multiple spectral fit windows to improve the spatial resolution

    NASA Astrophysics Data System (ADS)

    Pukite, Janis; Dörner, Steffen; Wagner, Thomas

    2015-04-01

    The Scanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) on the ENVISAT satellite probed the atmosphere at the day side of Earth in alternating sequences of nadir and limb measurements from August 2002 to April 2012. Limb measurements allow the retrieval of stratospheric profiles of various trace gases on a global scale. It has been shown that combining measurements of the same air volume from different viewing positions along the orbit, 2D distribution fields of stratospheric trace gases can be acquired in one inversion step. Since the atmospheric scattering and absorption processes are wavelength dependent, the spatial sensitivity for limb observations also varies with wavelength. In general, for longer wavelengths, photons from more remote areas along the line of sight are contributing stronger to the measurement than for shorter wavelengths because of the lower probability of Rayleigh scattering. In addition, the radiative transfer is modified by the ozone absorption structures making longer light paths less probable within strong ozone absorption bands. In this study, additional information on the spatial distribution of NO2 is investigated by analysing results obtained by Differential Optical Absorption Spectroscopy (DOAS) in various spectral fit windows. Combing the fit results in one profile retrieval algorithm helps to improve the spatial sensitivity and resolution of the measurements. The largest improvements for the spatial resolution and sensitivity are expected for the upper troposphere/ lower stratosphere (UTLS) region where the variation of the spatial sensitivity with wavelength is strongest.

  18. Nasal Absorption of Macromolecules from Powder Formulations and Effects of Sodium Carboxymethyl Cellulose on Their Absorption.

    PubMed

    Tanaka, Akiko; Furubayashi, Tomoyuki; Matsushita, Akifumi; Inoue, Daisuke; Kimura, Shunsuke; Katsumi, Hidemasa; Sakane, Toshiyasu; Yamamoto, Akira

    2016-01-01

    The nasal absorption of macromolecules from powder formulations and the effect of sodium carboxymethyl cellulose (CMC-Na) as a pharmaceutical excipient on their absorption were studied. Model macromolecules were fluorescein isothiocyanate-labeled dextran (average molecular weight of 4.4kDa, FD4) and insulin. The plasma concentration of FD4 after application of the powder containing 50% starch (control) was higher than that after application of the solution, and the absorption from 50% starch powder was enhanced by the substitution of starch with CMC-Na. The fractional absorption of FD4 after administration of the CMC-Na powder formulation was 30% and 40% higher than that after administration from the solution and the starch powder, respectively. The nasal absorption of insulin from the powder and the effect of CMC-Na were similar with those of FD4. The effective absorption of FD4 and insulin after application of powder with CMC-Na could be due to the increase in the nasal residence of FD4 and insulin. No damage in the nasal mucosa or dysfunction of the mucociliary clearance was observed after application of the drug powder and CMC-Na. The present findings indicate that nasal delivery of powder formulations with the addition of CMC-Na as an excipient is a promising approach for improving the nasal absorption of macromolecules. PMID:27598527

  19. A note on windowing for the waveform relaxation

    NASA Technical Reports Server (NTRS)

    Zhang, Hong

    1994-01-01

    The technique of windowing has been often used in the implementation of the waveform relaxations for solving ODE's or time dependent PDE's. Its efficiency depends upon problem stiffness and operator splitting. Using model problems, the estimates for window length and convergence rate are derived. The electiveness of windowing is then investigated for non-stiff and stiff cases respectively. lt concludes that for the former, windowing is highly recommended when a large discrepancy exists between the convergence rate on a time interval and the ones on its subintervals. For the latter, windowing does not provide any computational advantage if machine features are disregarded. The discussion is supported by experimental results.

  20. Measure Guideline. Energy-Efficient Window Performance and Selection

    SciTech Connect

    Carmody, John; Haglund, Kerry

    2012-11-01

    This document provides guidelines for the selection of energy-efficient windows in new and existing residential construction in all U.S. climate zones. It includes information on window products, their attributes and performance. It provides cost/benefit information on window energy savings as well as information on non-energy benefits such as thermal comfort and reduced HVAC demands. The report also provides information on energy impacts of design decisions such as window orientation, total glazing area and shading devices and conditions. Information on resources for proper window installation is included as well.

  1. Highly Insulating Windows Volume Purchase Program Final Report

    SciTech Connect

    2013-04-01

    This report documents the development, execution outcomes and lessons learned of the Highly Insulating Windows Volume Purchase (WVP) Program carried out over a three-year period from 2009 through 2012. The primary goals of the program were met: 1) reduce the incremental cost of highly insulating windows compared to ENERGY STAR windows; and 2) raise the public and potential buyers’ awareness of highly insulating windows and their benefits. A key outcome of the program is that the 2013 ENERGY STAR Most Efficient criteria for primary residential windows were adopted from the technical specifications set forth in the WVP program.

  2. Performance of special radiation-hardened optical fibers intended for use in the telecom spectral windows at a megagray level

    SciTech Connect

    Tomashuk, A.L.; Dianov, E.M.; Golant, K.M.; Khrapko, R.R.; Spinov, D.E.

    1998-06-01

    Gamma-radiation-induced absorption spectra (2.15 MGy(Si)) are compared in N-doped and pure silica fibers fabricated by surface plasma CVD-process under different regimes with the aim to reveal the chief absorption mechanisms in the telecom spectral windows and to work out an optimum fiber design. The long wavelength absorption edge is shown to be the main absorption mechanism at megagray doses. Its value increases with increasing bonded hydrogen concentration in the fiber glass network and is slightly greater in N-doped fibers. No nitrogen-related color centers have been revealed in the short wavelength loss edge, which is determined by chlorine impurity in silica.

  3. Serious drug interactions.

    PubMed

    Aronson, J

    1993-10-01

    Of the many varieties of drug interactions, which occur when the disposition or actions of one drug are changed by another, only a few are serious or potentially fatal. A representative outline of some of these illustrates the problem. Precipitant drugs are those which produce the interaction, and object drugs are those whose effects are changed. The interactions which are usually significant are those which alter the metabolism, involve renal excretion, or change the effects of the object drug, especially when the object drug has a low therapeutic index (cardiovascular drugs, anticoagulants, drugs acting on the brain, hypoglycemic drugs, hormones, and cytotoxic drugs). Warfarin toxicity, for example, is produced by aspirin, phenylbutazone, and azapropazone. The dosage requirements of warfarin are reduced by chloramphenicol, ciprofloxacin and other quinolones, erythromycin and some of the other macrolides, metronidazole and other imidazoles, tetracyclines, amiodarone, cimetidine (but not ranitidine), and fibrates. Potassium-depleting drugs can potentiate the action of digoxin, and the elimination of digoxin can be reduced by amiodarone, propafenone, quinidine, and verapamil. Combined oral contraceptives can lose effectiveness through the interaction of carbamazepine, griseofulvin, phenytoin, or rifampicin, which increase estrogen metabolism. In addition, broad-spectrum antibiotics such as ampicillin or tetracyclines also reduce contraceptive effectiveness by altering gut absorption. Even a single drink of an alcoholic beverage may be dangerous to people taking antidepressants, antihistamines, antipsychotic drugs, benzodiazepines, or lithium. Antihistamines suffer inhibited metabolism in the liver if taken in conjunction with the antifungal imidazoles and some of the macrolide antibiotics. Cardiotoxicity of antihistamines is also enhanced by drugs with similar cardiotoxic effects. Lithium potentiation is enhanced by the new serotonin-reuptake inhibitors, and lithium

  4. Developing Low-Conductance Window Frames: Capabilities and Limitations of Current Window Heat Transfer Design Tools

    SciTech Connect

    Gustavsen, Arild; Arasteh, Dariush; Jelle, Bjorn Petter; Curcija, Charlie; Kohler, Christian

    2008-09-11

    While window frames typically represent 20-30% of the overall window area, their impact on the total window heat transfer rates may be much larger. This effect is even greater in low-conductance (highly insulating) windows that incorporate very low-conductance glazing. Developing low-conductance window frames requires accurate simulation tools for product research and development. Based on a literature review and an evaluation of current methods of modeling heat transfer through window frames, we conclude that current procedures specified in ISO standards are not sufficiently adequate for accurately evaluating heat transfer through the low-conductance frames. We conclude that the near-term priorities for improving the modeling of heat transfer through low-conductance frames are: (1) Add 2D view-factor radiation to standard modeling and examine the current practice of averaging surface emissivity based on area weighting and the process of making an equivalent rectangular frame cavity. (2) Asses 3D radiation effects in frame cavities and develop recommendation for inclusion into the design fenestration tools. (3) Assess existing correlations for convection in vertical cavities using CFD. (4) Study 2D and 3D natural convection heat transfer in frame cavities for cavities that are proven to be deficient from item 3 above. Recommend improved correlations or full CFD modeling into ISO standards and design fenestration tools, if appropriate. (5) Study 3D hardware short-circuits and propose methods to ensure that these effects are incorporated into ratings. (6) Study the heat transfer effects of ventilated frame cavities and propose updated correlations.

  5. Optical effect of the contamination of infrared windows by the outgassing of materials in outer space

    NASA Technical Reports Server (NTRS)

    Silberman, E.

    1975-01-01

    The products and kinetics of outgassing from S13G paint were studied by using infrared absorption measurements of the material outgassed (using an evaporation cell and vacuum chamber). Two separate long-term experimental depositions from heated samples of the S13G paint were made. Before each experiment, the vacuum chamber and sample holder were carefully cleaned and outgassed to ensure that subsequent deposits on the colled-window were due only to the products evaporated from the sample. Results of experiments are listed and discussed.

  6. Study of noise reduction characteristics of multilayered panels and dual pane windows with Helmholtz resonators

    NASA Technical Reports Server (NTRS)

    Navaneethan, R.

    1981-01-01

    The experimental noise attenuation characteristics of flat, general aviation type, multilayered panels are discussed. Experimental results of stiffened panels, damping tape, honeycomb materials and sound absorption materials are presented. Single degree of freedom theoretical models were developed for sandwich type panels with both shear resistant and non-shear resistant core material. The concept of Helmholtz resonators used in conjunction with dual panel windows in increasing the noise reduction around a small range of frequency was tested. It is concluded that the stiffening of the panels either by stiffeners or by sandwich construction increases the low frequency noise reduction.

  7. Heavy absorption chillers: The Tortoise technology that can win

    SciTech Connect

    Irwin, F.E.

    1995-06-01

    Why has Absorption taken over 200 years to become a viable technology and secondarily what is the long term potential for heavy absorption technology? A third interesting question may be as some knowledgeable people in the North America industry have professed, is there a Window of Opportunity which was presented by the electric vapor compressor refrigerant issue which will be the last chance for absorption? Of course we know that absorption is not a new technology in 1994. It is however being rediscovered in many parts of the world by specifiers and engineers who are otherwise totally familiar with HVAC systems technology. As has been well documented in Japan, absorption heavy systems have been dominant for some time to the point that over 90% of the new units installed in the heavy systems category are absorption. Further by now 50% of the installed heavy systems tonnage in the country are absorption chillers. It did not take the electric vapor compressor refrigerant issue to make this huge market for absorption and there aren`t too many people in the HVAC business in Japan that view absorption as the {open_quotes}Tortoise technology.{close_quotes} If we only understood what the drivers were in Japan to create this absorption market then perhaps we could understand and possibly predict the long term potential for the technology in other markets of the world. We could actually go to work and look for markets that mirror the prevailing conditions in Japan. There will be those amongst us who will tell you that Japan is a unique market in almost every product category and most certainly with respect to heavy chiller systems.

  8. Two Cases of Malleostapedotomy in Congenital Oval Window Atresia

    PubMed Central

    Ahn, Sang Hyeon; Kim, Da Hee; Choi, Jae Young

    2013-01-01

    Congenital anomaly of the oval window with an abnormal facial nerve course is an uncommon embryological defect, which is related to the underdevelopment of second branchial arch derivatives. Some treatments for improving hearing levels are available; these include hearing aids, vestibulotomy, neo-oval window formation, and stapes surgeries, including incudostapedotomy and malleostapedotomy. However, surgery for congenital anomalies of the oval window has rarely been described, usually in very small series of patients. We describe two cases of congenital anomalies of the oval window with aberrant facial nerve courses. One was a 40-year-old male diagnosed with unilateral congenital oval window atresia; the other was a 10-year-old male diagnosed with bilateral congenital oval window atresia. We also describe the clinical manifestations and treatment outcomes of malleostapedotomy for congenital anomalies of the oval window with aberrant facial nerve courses. PMID:24653925

  9. Improving Wang-Landau sampling with adaptive windows

    NASA Astrophysics Data System (ADS)

    Cunha-Netto, A. G.; Caparica, A. A.; Tsai, Shan-Ho; Dickman, Ronald; Landau, D. P.

    2008-11-01

    Wang-Landau sampling (WLS) of large systems requires dividing the energy range into “windows” and joining the results of simulations in each window. The resulting density of states (and associated thermodynamic functions) is shown to suffer from boundary effects in simulations of lattice polymers and the five-state Potts model. Here, we implement WLS using adaptive windows. Instead of defining fixed energy windows (or windows in the energy-magnetization plane for the Potts model), the boundary positions depend on the set of energy values on which the histogram is flat at a given stage of the simulation. Shifting the windows each time the modification factor f is reduced, we eliminate border effects that arise in simulations using fixed windows. Adaptive windows extend significantly the range of system sizes that may be studied reliably using WLS.

  10. High-R Window Technology Development : Phase II Final Report.

    SciTech Connect

    Arasteh, Dariush

    1991-01-01

    Of all building envelope elements, windows always have had the highest heat loss rates. However, recent advances in window technologies such as low-emissivity (low-E) coatings and low- conductivity gas fillings have begun to change the status of windows in the building energy equation, raising the average R-value (resistance to heat flow) from 2 to 4 h-ft{sup 2}-{degrees}F/Btu. Building on this trend and using a novel combination of low-E coatings, gas-fills, and three glazing layers, the authors developed a design concept for R-6 to R-10 super'' windows. Three major window manufacturers produced prototype superwindows based this design for testing and demonstration in three utility-sponsored and -monitored energy-conserving homes in northwestern Montana. This paper discusses the design and tested performance of these three windows and identifies areas requiring further research if these window concepts are to be successfully developed for mass markets.

  11. High-R window technology development. Phase 2, Final report

    SciTech Connect

    Arasteh, D.

    1991-01-01

    Of all building envelope elements, windows always have had the highest heat loss rates. However, recent advances in window technologies such as low-emissivity (low-E) coatings and low- conductivity gas fillings have begun to change the status of windows in the building energy equation, raising the average R-value (resistance to heat flow) from 2 to 4 h-ft{sup 2}-{degrees}F/Btu. Building on this trend and using a novel combination of low-E coatings, gas-fills, and three glazing layers, the authors developed a design concept for R-6 to R-10 ``super`` windows. Three major window manufacturers produced prototype superwindows based this design for testing and demonstration in three utility-sponsored and -monitored energy-conserving homes in northwestern Montana. This paper discusses the design and tested performance of these three windows and identifies areas requiring further research if these window concepts are to be successfully developed for mass markets.

  12. Mechanical charactization of sonar window materials

    SciTech Connect

    DeTeresa, S.J.; Groves, S.E.; Harwood, P.J.; Sanchez, R.J.

    1996-03-25

    The three-dimensional mechanical behavior of thick Spectra/epoxy sonar window materials containing various special materials is summarized in this report. Three different materials, which were fabricated by two companies known as `A` and `B` were received from the Naval Warfare Center. The three materials designated `A with microspheres (A micron),` `A without microspheres (A),` and `B` were measured for all properties. The total number of tests was reduced through the assumption that the two orthogonal, in-place directions were identical. Consequently, these materials should have only six independent elastic variables. The measured constants and strengths are given.

  13. Infrared window materials and their fabrication

    SciTech Connect

    Chess, D.L.; White, W.B.

    1984-07-24

    Process for making densified ternary sulfide ceramics as infrared window materials using sulfide compounds MLn/sub 2/S/sub 4/ belonging to the Th/sub 3/P/sub 4/, CaFe/sub 2/O/sub 4/ and spinel structure types. These refractory sulfides show good sinterability especially when fired in flowing hydrogen sulfide, and they can be densified by a combination of hot-pressing and hot-isostatic pressing into ceramic pieces approaching their theoretical density with closed pores and which have good transmission characteristics in the infrared region.

  14. X-Windows PVT Widget Class

    NASA Technical Reports Server (NTRS)

    Barry, Matthew R.

    2006-01-01

    The X-Windows Process Validation Table (PVT) Widget Class ( Class is used here in the object-oriented-programming sense of the word) was devised to simplify the task of implementing network registration services for Information Sharing Protocol (ISP) graphical-user-interface (GUI) computer programs. Heretofore, ISP PVT programming tasks have required many method calls to identify, query, and interpret the connections and messages exchanged between a client and a PVT server. Normally, programmers have utilized direct access to UNIX socket libraries to implement the PVT protocol queries, necessitating the use of many lines of source code to perform frequent tasks. Now, the X-Windows PVT Widget Class encapsulates ISP client server network registration management tasks within the framework of an X Windows widget. Use of the widget framework enables an X Windows GUI program to interact with PVT services in an abstract way and in the same manner as that of other graphical widgets, making it easier to program PVT clients. Wrapping the PVT services inside the widget framework enables a programmer to treat a PVT server interface as though it were a GUI. Moreover, an alternate subclass could implement another service in a widget of the same type. This program was written by Matthew R. Barry of United Space Alliance for Johnson Space Center. For further information, contact the Johnson Technology Transfer Office at (281) 483-3809. MSC-23582 Shuttle Data Center File- Processing Tool in Java A Java-language computer program has been written to facilitate mining of data in files in the Shuttle Data Center (SDC) archives. This program can be executed on a variety of workstations or via Web-browser programs. This program is partly similar to prior C-language programs used for the same purpose, while differing from those programs in that it exploits the platform-neutrality of Java in implementing several features that are important for analysis of large sets of time-series data

  15. Window taper functions for subaperture processing.

    SciTech Connect

    Doerry, Armin Walter

    2013-12-01

    It is well known that the spectrum of a signal can be calculated with a Discrete Fourier Transform (DFT), where best resolution is achieved by processing the entire data set. However, in some situations it is advantageous to use a staged approach, where data is first processed within subapertures, and the results are then combined and further processed to a final result. An artifact of this approach is the creation of grating lobes in the final response. The nature of the grating lobes, including their amplitude and spacing, is an artifact of window taper functions, subaperture offsets, and subaperture processing parameters. We assess these factors and exemplify their effects.

  16. Fused Silica and Other Transparent Window Materials

    NASA Technical Reports Server (NTRS)

    Salem, Jon

    2016-01-01

    Several transparent ceramics, such as spinel and AlONs are now being produced in sufficient large areas to be used in space craft window applications. The work horse transparent material for space missions from Apollo to the International Space Station has been fused silica due in part to its low coefficient of expansion and optical quality. Despite its successful use, fused silica exhibits anomalies in its crack growth behavior, depending on environmental preconditioning and surface damage. This presentation will compare recent optical ceramics to fused silica and discuss sources of variation in slow crack growth behavior.

  17. "Virtual Cockpit Window" for a Windowless Aerospacecraft

    NASA Technical Reports Server (NTRS)

    Abernathy, Michael F.

    2003-01-01

    A software system processes navigational and sensory information in real time to generate a three-dimensional-appearing image of the external environment for viewing by crewmembers of a windowless aerospacecraft. The design of the particular aerospacecraft (the X-38) is such that the addition of a real transparent cockpit window to the airframe would have resulted in unacceptably large increases in weight and cost. When exerting manual control, an aircrew needs to see terrain, obstructions, and other features around the aircraft in order to land safely. The X-38 is capable of automated landing, but even when this capability is utilized, the crew still needs to view the external environment: From the very beginning of the United States space program, crews have expressed profound dislike for windowless vehicles. The wellbeing of an aircrew is considerably promoted by a three-dimensional view of terrain and obstructions. The present software system was developed to satisfy the need for such a view. In conjunction with a computer and display equipment that weigh less than would a real transparent window, this software system thus provides a virtual cockpit window. The key problem in the development of this software system was to create a realistic three-dimensional perspective view that is updated in real time. The problem was solved by building upon a pre-existing commercial program LandForm C3 that combines the speed of flight-simulator software with the power of geographic-information-system software to generate real-time, three-dimensional-appearing displays of terrain and other features of flight environments. In the development of the present software, the pre-existing program was modified to enable it to utilize real-time information on the position and attitude of the aerospacecraft to generate a view of the external world as it would appear to a person looking out through a window in the aerospacecraft. The development included innovations in realistic

  18. Seven-effect absorption refrigeration

    DOEpatents

    DeVault, Robert C.; Biermann, Wendell J.

    1989-01-01

    A seven-effect absorption refrigeration cycle is disclosed utilizing three absorption circuits. In addition, a heat exchanger is used for heating the generator of the low absorption circuit with heat rejected from the condenser and absorber of the medium absorption circuit. A heat exchanger is also provided for heating the generator of the medium absorption circuit with heat rejected from the condenser and absorber of the high absorption circuit. If desired, another heat exchanger can also be provided for heating the evaporator of the high absorption circuit with rejected heat from either the condenser or absorber of the low absorption circuit.

  19. Seven-effect absorption refrigeration

    DOEpatents

    DeVault, R.C.; Biermann, W.J.

    1989-05-09

    A seven-effect absorption refrigeration cycle is disclosed utilizing three absorption circuits. In addition, a heat exchanger is used for heating the generator of the low absorption circuit with heat rejected from the condenser and absorber of the medium absorption circuit. A heat exchanger is also provided for heating the generator of the medium absorption circuit with heat rejected from the condenser and absorber of the high absorption circuit. If desired, another heat exchanger can also be provided for heating the evaporator of the high absorption circuit with rejected heat from either the condenser or absorber of the low absorption circuit. 1 fig.

  20. Drugs, drugs--who has the drugs?

    PubMed

    Blair, James

    2012-01-01

    Drug diversion, although on the increase, is not the only problem involving drugs that hospital security officials should be concerned with. Growing drug shortages, offshore production, counterfeiting, and weaknesses in the drug supply chain in case of a world-wide pandemic, are even greater causes for concern, the author claims. PMID:22423518