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Release Time (release + time)
Selected AbstractsLong-term variation in brown trout, Salmo trutta L., stocking success in a large lake: interplay between availability of suitable prey and size at releaseECOLOGY OF FRESHWATER FISH, Issue 4 2005P. Hyvärinen Abstract , Factors affecting long-term variation in brown trout, Salmo trutta L., stocking success were examined in a large lake, Lake Oulujärvi, in central Finland. Brown trout were stocked in spring (late May to early June) in 1974,1991 and in summer (late June to early July) in 1992,2001. The biomass of the vendace, Coregonus albula (L.), population (prey) at release time had the largest positive effect on stocking success within both periods: biomass of adult vendace in spring and both 0+ and adult vendace in summer. Increasing the size of stocked fish had a positive effect if the vendace available at release were only adults. The increasing trend of predator-catch-per-unit-effort (CPUE) [combined CPUE of northern pike Esox lucius L., burbot Lota lota (L.), and pike-perch Stizostedion lucioperca (L.)] through the study period and its negative effect on trout stocking success suggested an increasing effect of predation within the entire time series. Resumen 1. Dado lo impredecible que son los resultados de las repoblaciones, se hace necesario conocer los mecanismos que afectan el éxito de los peces soltados para minimizar los riesgos de error en altas inversiones de repoblaciones. Podría existir una ventana óptima para las sueltas que produzca las condiciones más favorables - tales como la ausencia de predadores en la zona de suelta y la disponibilidad de presas apropiadas - bajo las que cualquier pez soltado pueda sobrevivir y generar una producción máxima. El fin de este estudio fue examinar como factores tales como la abundancia de las poblaciones de presas y predadores, y las tasas, tamaños y estaciones de repoblación pueden explicar las variaciones anuales a largo plazo (años 1974,1991) en el éxito de repoblación de Salmo trutta L. en el Lago Oulujärvi (928 km2, Finlandia central). 2. Individuos de S. trutta fueron repoblados en primavera (finales de Mayo , principios de Junio) durante los años 1974,1991 y en verano (finales de Junio , principios de Julio) durante los años 1992,2001. Los resultados de análisis de regresión por pasos mostró que la biomasa de Coregonus albula (L.) adultos (i.e., presas) en el momento de la suelta tuvieron el mayor efecto positivo sobre el éxito de la repoblación en dos períodos: la biomasa de adultos de C. albula en primavera y ambos dos, juveniles 0+ y adultos en verano. Incrementar el tamaño de los peces repoblados tuvo un efecto positivo si los C. albula disponibles en el momento de la suelta fueron solamente adultos (repoblaciones primaverales). La tendencia a incrementar los CPUE-predadores (CPUE combinadas de Esox lucius L., Lota lota (L.), y Stizostedion lucioperca (L.)) a lo largo del periodo de estudio y su efecto negativo sobre el éxito de las repoblaciones de S. trutta sugirió un mayor efecto de la predación sobre la series temporales completas. 3. Concluimos que el momento de la repoblación juega un papel más importante como determinante de la mejor ventana para la repoblación de S. trutta de lagos. Individuos de S. trutta de tamaños <200 g deberían ser repoblados solo si presas de pequeño tamaño (individuos 0+ de C. albula en verano) son también abundantes en el momento y en el área de la suelta. Si las presas disponibles son solos grandes (adultos de C. albula en primavera), el tamaño de repoblación debería ser mayor con individuos de S. trutta claramente mayores de 200 g porque el mayor tamaño amplia el rango de tamaños de las presas disponibles. [source] Hierachically Nanostructured Mesoporous Spheres of Calcium Silicate Hydrate: Surfactant-Free Sonochemical Synthesis and Drug-Delivery System with Ultrahigh Drug-Loading CapacityADVANCED MATERIALS, Issue 6 2010Jin Wu Ultrahigh drug-loading capacity and the linear relationship between the cumulative amount of released drug and the natural logarithm of release time were discovered for the hierachically nanostructured mesoporous spheres of calcium silicate hydrate (CSH) obtained by a surfactant-free sonochemical method (see figure). During the release of loaded ibuprofen in simulated body fluid, CSH gradually transformed to hydroxyapatite. [source] Control of thermo reversible gelation of methylcellulose using polyethylene glycol and sodium chloride for sustained delivery of ophthalmic drugJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2010Mrinal Kanti Bain Abstract The effect of molecular weight of polyethyleneglycol (PEG) and sodium chloride (NaCl) on the gelation temperature of methylcellulose (MC) was studied with the objective to develop a MC based formulation for sustained delivery of ophthalmic drug. The gelation temperature of 1% MC was 60 ± 0.40°C. It was found that the gelation temperature of MC was reduced with the addition of 10% PEG and extent of reduction of gelation temperature was depended on the molecular weight of PEG at same PEG concentration of 10%. The gelation temperature of MC was reduced by 10.4 to 5.9°C with the increasing molecular weight of PEG starting from 400 to 20,000 (Mn) depending on the method of determination of gelation temperature. To reduce the gelation temperature of MC close to physiological temperature (37°C), 6% NaCl was added in the different MC-PEG combinations containing different molecular weight of PEG. It was observed that the drug release time increased from 5 to 8 h with the increase in molecular weight of PEG from 400 to 20,000 (Mn) and this was due to the maximum viscosity and gel strength of MC-PEG20000-NaCl ternary combination. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Advances in Transcatheter Patch Occlusion of Heart DefectsJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 5 2003E. B. SIDERIS M.D. The transcatheter patch device consists of the following components: a sleeve type polyurethane patch, a double balloon support catheter and a retrieval thread. It has been applied in a variety of heart defects, including various types of atrial septal defects, ventricular septal defects and patent ductus arteriosus. New advances include an accelerated release time for many applications and better immobilization. Using accelerated fibrin formation principles, transcatheter path release time has been decreased to less than 24 hours for patent ductus arteriosus and some ventricular septal defects; in contrast 48 hours are required for patch release in large atrial septal defects. The device is also unlikely to move away from the septum using the new immobilization methods. Since the patch is inflatable, only three sizes are required for the occlusion of all defect types and sizes. Conclusion: In conclusion the transcatheter patch is applicable in a variety of heart defects; the procedure is safer and faster, becoming outpatient, for many applications. Furthermore, it is cost effective. (J Interven Cardiol 2003;16:419,424) [source] Colon Delivery Efficiencies of Intestinal Pressure-controlled Colon Delivery Capsules Prepared by a Coating Machine in Human SubjectsJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 10 2000ZHAOPENG HU Large quantities of pressure-controlled colon delivery capsules (PCDCs) were prepared by a Hicoater-mini pharmaceutical coating machine and colon delivery efficiencies were evaluated in man. Caffeine powder as a model drug was suspended with a polyethylene glycol (PEG) 1000 suppository base at 50°C, and was hardened in no. 0- and no. 2-sized capsular shapes. The capsule-shaped suppositories were coated with 5% w/v ethanolic ethylcellulose (7G grade) solution using the coating machine. By increasing the coating weight of ethylcellulose from 28.6 ± 1.1 mg to 45.3 ± 0.2 mg, the mean coating thickness of no. 0 PCDCs increased from 56 ± 1 ,m to 64 ± 1 ,m. With no. 2 PCDCs, the mean coating thickness increased from 50 ± 1 ,m to 57 ± 1 ,m by increasing the coating weight of ethylcellulose from 8.1 ± 0.5 mg to 11.2 ± 0.3 mg. The no. 0 PCDCs, having a mean ethylcellulose coating membrane thicknesses of 56± 1 ,m (type 1) and 64 ± 1 ,m (type 2), as well as no. 2 PCDCs, having thicknesses of 50 ± 1 ,m (type 3) and 57 ± 1 ,m (type 4), were used for in-vivo evaluation in man. After oral administration of test preparations containing 75 mg of caffeine, saliva samples were obtained and salivary caffeine levels were measured by an HPLC method. The first appearance time, Ti, of caffeine in the saliva was used as a parameter for the estimation of the release time of caffeine from PCDCs in the gastrointestinal tract. The mean Ti values of no. 0 PCDCs were 3.3 ± 0.3 h for type-1 and 5.3 ± 0.3 h for type-2 preparations while the mean Ti values of no. 2 PCDCs were 4.3 ± 0.5 h for type 3 and 5.3 ± 0.3 h for type 4. There were good correlations between ethylcellulose coating membrane thicknesses and in-vivo Ti values. A colon arrival time of 5 h was reported in our subjects by gastrointestinal magnetomarkergraphy. PCDCs having a mean coating thickness of 64± 1 ,m for no. 0 capsules and of 57 ± 1 ,m for no. 2 capsules were thought to deliver caffeine to the human colon efficiently. [source] Follow-Up Comparisons of Intervention and Comparison Schools in a State Tobacco Prevention and Control InitiativeJOURNAL OF SCHOOL HEALTH, Issue 3 2006Phyllis Gingiss The intervention, which was funded through the Texas Department of State Health Services, consisted of guidance, training, technical assistance, and reimbursement of approximately $2000 per year for program expenses. Self-administered written surveys for Principals and Health Coordinators, based on the School Health Education Profile Tobacco Module, were designed for periodic assessment of the status of school programs. Surveys were sent in 2002 to intervention (n = 74) and comparison (n = 60) schools. Response to the Principal Survey was received from 109 (81%) schools, and response to the Health Coordinator Survey was received from 84 (63%) schools. Survey analysis showed that intervention schools more frequently (p , .05) reported: (1) being extremely or moderately active in student cessation support, teacher training, policy development, family involvement, and assessment of the prevention program; (2) using recommended curricula, offering more tobacco-related lessons, involving more teachers, and using more recommended teaching methods such as role-playing, simulations or practice, and peer educators; and (3) having more interest in staff development and more funding to purchase release time. Similarities across schools are provided, as well as recommendations for future planning. (J Sch Health. 2006;76(3):98-103) [source] Photopolymerization of alicyclic methacrylate hydrogels for controlled releasePOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 7 2009Jing Han Abstract Alicyclic hydroxy methacrylate monomer, o -hydroxycyclohexyl methacrylate (HCMA), was synthesized and characterized by Fourier transformed infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance spectroscopy (1H-NMR). Photopolymerization kinetics of HCMA was investigated via real-time infrared spectroscopy (RT-IR). Polymeric network hydrogels based on hydroxyethyl methacrylate (HEMA) and HCMA were prepared by using the photopolymerization technique. Mechanical strength, swelling characteristic, and controlled release behavior of hydrogels with various feed compositions were studied. Poly(HEMA-co-HCMA) hydrogel had higher storage modulus than that of poly(HEMA) hydrogel as investigated by dynamic mechanical analysis (DMA). Acid orange 8 was used as a model drug for the investigation of drug release behavior of copolymeric hydrogels. Results indicated that increase in HCMA ratio in hydrogel composition could reduce the swelling rate and prolong the release time. Scanning electron microscopy (SEM) was also utilized to study the surface morphology of hydrogels, and the results indicated that HCMA content influenced pore diameter on the hydrogel surface. Copyright © 2008 John Wiley & Sons, Ltd. [source] Analysis of Revenue Maximization Under Two Movie-Screening PoliciesPRODUCTION AND OPERATIONS MANAGEMENT, Issue 1 2010Milind Dawande A few weeks before the start of a major season, movie distributors arrange a private screening of the movies to be released during that season for exhibitors and, subsequently, solicit bids for these movies (from exhibitors). Since the number of such solicitations far exceeds the number of movies that can be feasibly screened at a multiplex (i.e., a theater with multiple screens), the problem of interest for an exhibitor is that of choosing a subset of movies for which to submit bids to the distributors. We consider the problem of the selection and screening of movies for a multiplex to maximize the exhibitor's cumulative revenue over a fixed planning horizon. The release times of the movies that can potentially be selected during the planning horizon are known a priori. If selected for screening, a movie must be scheduled through its obligatory period, after which its run may or may not be extended. The problem involves two primary decisions: (i) the selection of a subset of movies for screening from those that can potentially be screened during the planning horizon and (ii) the determination of the duration of screening for the selected movies. We investigate two basic and popular screening policies: preempt-resume and non-preempt. In the preempt-resume policy, the screening of a movie can be preempted and resumed in its post-obligatory period. In the non-preempt policy, a movie is screened continuously from its release time until the time it is permanently withdrawn from the multiplex. We show that optimizing under the preempt-resume policy is strongly NP-hard while the problem under the non-preempt policy is polynomially solvable. We develop efficient algorithms for the problem under both screening policies and show that the revenue obtained from the preempt-resume policy can be significantly higher as compared with that from the non-preempt policy. Our work provides managers of multiplexes with valuable insights into the selection and screening of movies and offers an easy-to-use computational tool to compare the revenues obtainable from adopting these popular policies. [source] Total System Reliability: Integrated Model for Growth and Test TerminationQUALITY AND RELIABILITY ENGINEERING INTERNATIONAL, Issue 4 2005John Donovan Abstract Reliability demonstration testing is not the most efficient method of assuring product reliability prior to shipment. It is costly, time consuming and has inherent technical and social limitations. The dilemma facing the reliability and quality engineer is whether to continue demonstration testing and risk shipping a product late or ship the product and risk warranty and field service returns. Either option can cause the company to lose significant market share and profit. This paper sets out to solve this dilemma by meeting both the time to market constraints and the product reliability goals. The weaknesses of existing reliability demonstration techniques are explored and a comprehensive methodology is introduced involving controlled development processes, stress testing, root cause determination and process change feedback mechanisms. All prototype products are manufactured on the final volume process line resulting in the early identification and correction of process-related problems. Testing commences on the first available prototypes with system stress/robust testing being employed to stimulate failures, determine their root cause and correct them. Reliability growth modelling assesses the ongoing improvements occurring in reliability during the development cycle, while a statistical stopping rule is used to determine the optimal product release time without risking product warranty. The approach is applicable to systems incorporating both hardware and software elements. The methodology has been validated on three development projects of telecommunication systems comprising hardware and software. In addition to enhancing team behaviour and performance, the development times have been reduced by 14% and the ramp-up time to full worldwide product shipments has been reduced by 50%. Copyright © 2005 John Wiley & Sons, Ltd. [source] Scheduling dispensing and counting in secondary pharmaceutical manufacturingAICHE JOURNAL, Issue 5 2009Michele Ciavotta Abstract In this article, we describe a general methodology for operations scheduling in dispensing and counting departments of pharmaceutical manufacturing plants. The departments are modeled as a multiobjective parallel machines scheduling problem under a number of both standard and realistic constraints, such as release times, due dates and deadlines, particular sequence-dependent setup times, machine unavailabilities, and maximum campaign size. Main characteristics of the methodology are the modularity of the solution algorithms, the adaptability to different objectives and constraints to fulfill production requirements, the easiness of implementation, and the ability of incorporating human experience in the scheduling algorithms. Computational experience carried out on two case studies from a real pharmaceutical plant shows the effectiveness of this approach. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Maximizing project cash availabilityNAVAL RESEARCH LOGISTICS: AN INTERNATIONAL JOURNAL, Issue 4 2006Joseph G. Szmerekovsky Abstract Consider a project during the life cycle of which there are cash payouts and in-flows. To better meet his financial commitments, the project owner would like to meet all deadlines without running out of cash. We show that the cash availability objective is similar to the total weighted flowtime used to measure work-in-progress performance in the scheduling and inventory control literatures. In this article we provide several specialized solution methods for the problem of minimizing total weighted flowtime in an arbitrary acyclic project network, subject to activity release times and due dates, where the activity weights may be positive or negative and represent cash in- and out-flows. We describe the structure of an optimal solution and provide several efficient algorithms and their complexity based on mincost and maxflow formulations. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2006 [source] The impact of firm introductory strategies on consumers' perceptions of future product introductions and purchase decisionsTHE JOURNAL OF PRODUCT INNOVATION MANAGEMENT, Issue 2 2001Derrick S. Boonea In this research, we develop and test a model of the consumer's decision to immediately purchase a technologically advanced product or to delay such a purchase until a future generation of the product is released. We propose that for technologically advancing products, consumers consider both performance lag (how far behind am I now) and expected performance gain (how far ahead will I be if I wait to buy a future expected release) in their purchase decisions. Furthermore, we hypothesize that a firm's past product introductory strategy can significantly influence consumer perceptions of performance lag, performance gain, and the rate at which a product is advancing technologically. We also propose that these perceptions of lag, gain and rate of technological change influence purchase action and ultimately determine whether or not a consumer will delay or immediately purchase a firm's current technological offering. We investigate the above relationships by introducing a model of consumer purchase behavior that incorporates the effects of a firm's frequency and pattern of next generation product introduction, and test the impact of different introductory strategies on performance lag, gain, rate of change perceptions, and purchase action. In our first study we test our model in a monopolistic setting and show that, holding all else fixed, infrequent product upgrades and/or increasing intergenerational release times result in consumers perceiving larger performance lags and gains. We also show that, holding all else fixed, consumers with larger performance lags and/or gains are less likely to delay their purchases of the currently best available product. In our second study we test our model in a competitive setting and show that, holding all else fixed, a firm's past pattern of new product introduction can influence consumers' perceptions of the firm's product's rate of technological change. We also find that consumers are more likely to purchase products which they perceive to have higher rates of technological change. The key insight from this research is that firms have a strategic tool at their disposal that has been overlooked,the pattern of introduction of next generation products. Our findings suggest that a change in the frequency and/or pattern of introduction, in and of themselves, can influence consumers' perceptions of future product introductions, and ultimately influence their purchase actions. Specifically, we demonstrate that by better understanding consumers' purchase timing decisions, firms may be able to induce purchase on the basis of introductory frequency and pattern alone. Additionally, we demonstrate that by strategically managing consumer expectations of future product introductions, firms may be able to decrease the purchase likelihoods of competing products. Implications of our research and its application to the pattern and timing of preannouncements for new products are also explored. [source] Effects of Drug Hydrophobicity on Liposomal StabilityCHEMICAL BIOLOGY & DRUG DESIGN, Issue 1 2008David R. Khan A major obstacle in drug delivery is the inability to effectively deliver drugs to their intended biological target without deleterious side-effects. Delivery vehicles such as liposomes can minimize toxic side-effects by shielding the drug from reaction with unintended targets while in systemic circulation. Liposomes have the ability to accommodate both hydrophilic and hydrophobic drugs, either in the internal aqueous core or the lipid bilayer, respectively. In the present study, fluorescein and rhodamine have been used to model hydrophilic and hydrophobic drugs, respectively. We have compared the stabilities of liposomes encapsulating these fluorophores as a function of lipid content, time, and temperature. At 25 and 37 °C, liposomes containing distearoyl phosphatidylcholine as the major phospholipid component were found to be more stable over time than those containing dipalmitoyl phosphatidylcholine, regardless of the fluorophore encapsulated. Liposomes loaded with fluorescein were found to be more stable than those with rhodamine. Dipalmitoyl phosphatidylcholine liposomes that encapsulated rhodamine were the least stable. The results indicate that the physical properties of the drug cargo play a role in the stability, and hence drug delivery kinetics, of liposomal delivery systems, and desired drug release times can be achieved by adjusting/fine-tuning the lipid compositions. [source] | |||||||||||||||||||