Low Volume (low + volume)

Distribution by Scientific Domains


Selected Abstracts


Biofilm Growth and Bed Fluidization in a Fluidized Bed Reactor Packed with Support Materials of Low Density,

ENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 2 2004
R.A. Saucedo-Terán
Abstract Support materials of low-density for fluidized bed reactors provide several operational advantages, including lower energy requirements and proper biofilm growth balance. The aim of this investigation was to study the extent of biofilm growth and bed fluidization in an experimental reactor, using polyester resin (,pr,=,1220,kg/m3) and vitrified expanded perlite (,vep,=,1710,kg/m3) as alternative support materials to conventional silica sand. A noteworthy amount of biofilm was observed to be attached to both support materials from the very beginning of the bioreactor operation. Nevertheless, there were significant variations in biofilm growth and activity over the course of the experimental trials. For both perlite and polyester beds, the highest biofilm mass and the highest total number of mesophilic bacteria were observed between the 7th and the 10th day, showing a steady state trend at the end of the experimental runs. The chemical oxygen demand (COD) removal levels were concomitant with biofilm mass and total mesophilic bacteria changes, although the polyester bed efficiency was slightly higher than that for the perlite bed. As expected, the polyester bed was fluidized at a lower re-circulation flow compared to the perlite bed. Reactor back-washing was not required for these support materials since biomass excess was adequately separated by means of a special internal device. The efficiencies of removal of organic matter achieved were acceptable (up to 78,%) despite the low volume of the support material (25,%) and the low hydraulic retention time (30,min). [source]


Using process-oriented holonic (PrOH) modelling to increase understanding of information systems

INFORMATION SYSTEMS JOURNAL, Issue 5 2008
Ben Clegg
Abstract., Methodologies for understanding business processes and their information systems (IS) are often criticized, either for being too imprecise and philosophical (a criticism often levied at softer methodologies) or too hierarchical and mechanistic (levied at harder methodologies). The process-oriented holonic modelling methodology combines aspects of softer and harder approaches to aid modellers in designing business processes and associated IS. The methodology uses holistic thinking and a construct known as the holon to build process descriptions into a set of models known as a holarchy. This paper describes the methodology through an action research case study based in a large design and manufacturing organization. The scientific contribution is a methodology for analysing business processes in environments that are characterized by high complexity, low volume and high variety where there are minimal repeated learning opportunities, such as large IS development projects. The practical deliverables from the project gave IS and business process improvements for the case study company. [source]


A review on microwave baking of foods

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 2 2001
Gülüm Sumnu
Summary Microwaves interact with polar molecules and charged particles of food to generate heat. There are differences between the heating mechanisms of microwave and conventional heating. The use of microwave heating has the advantage of saving energy and time, improving both nutritional quality and acceptability of some foods by consumers. Microwave ovens are successfully used both in homes and in the food service industry. However, there are still problems in perfecting microwave baking, therefore it is a popular research area. The main problems found to occur in microwave-baked food products are low volume, tough or firm texture, lack of browning and flavour development. Recent studies aim to improve the quality of microwave-baked products. This article reviews the basic principles of microwave baking, problems commonly occurring in microwave-baked products and finally studies published concerning microwave-baked products. [source]


Orientational disruption of codling moth, Cydia pomonella (L.) (Lep., Tortricidae), by concentrated formulations of microencapsulated pheromone in flight tunnel assays

JOURNAL OF APPLIED ENTOMOLOGY, Issue 9-10 2005
L. L. Stelinski
Abstract:, The effects of two formulations of microencapsulated pheromone (CheckMate CM-F), containing 14.3% (E,E)-8,10-dodecadien-1-ol (codlemone), on the behaviour of the male codling moth, Cydia pomonella (L.), were evaluated in a flight tunnel after several periods of formulation ageing. The two treatments of CheckMate CM-F evaluated consisted of the label-recommended field rate of 50 g active ingredient (a.i.)/ha diluted in: (1) a standard 1000 l of water (low concentration 0.05 g/l), and (2) a low volume of 100 l of water (high concentration 0.5 g/l). The low-concentration treatment was formulated by diluting 0.071 ml of CheckMate CM-F in 500 ml of water and the high-concentration treatment contained 0.71 ml of CheckMate CM-F in 500 ml of water. Wax-paper strips (2.1 × 20 cm) were treated at 0.06 ml of solution/cm2. The mean (±SE) number of CheckMate CM-F microcapsules adhering to treated wax-paper strips in the high-concentration treatment (398 ± 38) was sevenfold greater than that (57 ± 5) counted on wax-paper strips treated with the low concentration. Both low- and high-concentration treatments prevented anemotactic orientation of male codling to an adjacent 0.1 mg codlemone lure for up to 24 h after application. These moths flew out of the release cages, but exhibited erratic and short flights not restricted to any plume and ending at the tunnel walls or the floor. This occurred with approximately 60 and 400 microcapsules per wax-paper strip in the low- and high-concentration treatments, releasing codlemone at approximately 0.15 and 1.5 ,g/h respectively. After 2 days of ageing, the low-concentration treatment no longer interfered with the ability of males to find the codlemone lure. However, the number of males contacting the lure was significantly reduced for up to 6 days with the high-concentration treatment relative to the control and low-concentration treatments. The high-concentration treatment no longer impeded normal orientational flight after 2,6 days of ageing; but, it diverted males from the codlemone lure by causing them to land on the adjacent treated wax-paper strips. This occurred at a release rate of approximately 0.7 ,g codlemone/h from approximately 400 microcapsules per wax-paper strip distributed as clumps of approximately 30 microcapsules per 14 mm2. We suggest that an initial but short-lived disruption mechanism like camouflage is followed by a longer period of false-plume following to clumps of microcapsules. The low-volume, concentrated application method for disseminating pheromone microcapsules warrants further investigation for moth codling, as well as other pests because this approach may improve the efficacy without the need for increasing the field application rate. [source]


Sturgeon aquaculture in China: status of current difficulties as well as future strategies based on 2002,2006/2007 surveys in eleven provinces

JOURNAL OF APPLIED ICHTHYOLOGY, Issue 6 2009
By R. Li
Summary A nationwide survey in July and August 2007 employed a representative sample of Chinese sturgeon farms from 2002,2006/2007, including data from previous surveys and official statistics dating back to 1998, showing that the development of China's sturgeon aquaculture has progressed steadily in the past few years. Acipenser baerii and Amur hybrids (Acipenser schrenckii × Huso dauricus) have become the dominant cultured species, accounting for 80% of total production. Production centers moved from the southeastern coast towards the midwestern inland provinces, where cold freshwater resources are available in abundance. The paper presents production trends as well as the price structure for commercial fish/meat and juveniles in the various provinces and also considers import and export data for products, fertilized eggs and fingerlings. Results show that: (i) production of juveniles in hatcheries has risen only slightly during the survey period; (ii) the number of larvae obtained from the wild gradually declines each year; (iii) the price for commercial fish/meat drastically declined between 1998 to 2002, but remained stable from 2002 to 2007; and (iv) total production from the 83 surveyed farms was almost stable from 2002 to 2007. Major problems influencing sustainable development of sturgeon aquaculture were identified, including: (i) insufficient domestic supply of larvae and the ban for commercial use of A. sinensis; (ii) disorganized hybridization; (iii) the potential threat to the genetics of natural stocks in the Yangtze River; (iv) diseases originating from environmental pollution and poor-quality fish feed; (v) limited domestic markets; (vi) low volume of sturgeon export due to lack of intensive processing; and (vii) lack of organizational structure in the industry. [source]


Quantitative evaluation of prostatectomy for benign prostatic hypertrophy under a national health insurance law: a multi-centre study

JOURNAL OF EVALUATION IN CLINICAL PRACTICE, Issue 1 2002
D. Pilpel PhD
Abstract Assessing regional variation between various medical centres in diagnostic and surgical processes is an approach aimed at evaluating the quality of care. This study analyses the differences between eight medical centres in Israel, where all citizens are covered by medical insurance, through the National Health Insurance Law (NHIL). The analysis refers to the diagnostic process, type of surgery and immediate post-surgical complications associated with prostatectomy for benign prostatic hypertrophy (BPH), which is the most frequent surgical procedure performed on men aged 50+. The study sample was comprized of 261 consecutive prostatectomy patients operated on in eight Israeli medical centres (MC), located in various parts of the country, between November 1996 and April 1997. Co-operation with participating directors of surgical wards was obtained after confidentiality of information had been assured. Surgeons in selected departments abstracted data routinely recorded in the patient's file and filled-out a standard one-page questionnaire. The following items were included: age, the presence of accompanying chronic diseases, preoperative tests, type of operation, and post-surgical complications. In the various MCs 32.6% of the patients underwent more than five preoperative tests ranging from 8.9% to 88.9% (<0.01). Assessment of kidney and bladder normality ranged from 75% to 100% (P < 0.01). The rate of patients whose prostatic symptoms (I-PSS) were assessed ranged from 0% to 79% (P < 0.01). There were also differences in severity of prostatism between the MCs, with severe symptoms ranging from 54.0% to 89.3% (P < 0.05), for type of operation performed (for ,open' prostatectomies, 35.4% to 68.0%, P < 0.01) and post-operative complications (19.0% to 41.6%, P = 0.07). After controlling for case-mix, type of operation was the most important predictor for post-surgical complications. MCs with low volume of surgeries had a higher rate of postoperative complications. We conclude that diagnostic and type of operation and post-surgical complications differed between various MCs. Participating surgeons were willing to fill out a one-page standard questionnaire from data routinely recorded in patients' files. [source]


Soil nutrient supply and biomass production in a mixed forest on a skeleton-rich soil and an adjacent beech forest

JOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 6 2002
Dirk Hölscher
Abstract In the natural forest communities of Central Europe, beech (Fagus sylvatica L.) predominates in the tree layer over a wide range of soil conditions. An exception with respect to the dominance of beech are skeleton-rich soils such as screes where up to 10 broad-leaved trees co-exist. In such a Tilia-Fagus-Fraxinus-Acer-Ulmus forest and an adjacent mono-specific beech forest we compared (1) soil nutrient pools and net nitrogen mineralization rates, (2) leaf nutrient levels, and (3) leaf litter production and stem increment rates in order to evaluate the relationship between soil conditions and tree species composition. In the mixed forest only a small quantity of fine earth was present (35 g l,1) which was distributed in patches between basalt stones; whereas a significantly higher (P < 0.05) soil quantity (182 g l,1) was found in the beech forest. In the soil patches of the mixed forest C and N concentrations and also concentrations of exchangeable nutrients (K, Ca, Mg) were significantly higher than in the beech forest. Net N mineralization rates on soil dry weight basis in the mixed forest exceeded those in the beech forest by a factor of 2.6. Due to differences in fine earth and stone contents, the volume related soil K pool and the N mineralization rate were lower in the mixed forest (52 kg N ha,1 yr,1, 0,10 cm depth) than in the beech forest (105 kg N ha,1 yr,1). The leaf N and K concentrations of the beech trees did not differ significantly between the stands, which suggests that plant nutrition was not impaired. In the mixed forest leaf litter fall (11,%) and the increment rate of stem basal area (52,%) were lower than in the beech forest. Thus, compared with the adjacent beech forest, the mixed forest stand was characterized by a low volume of patchy distributed nutrient-rich soil, a lower volume related K pool and N mineralization rate, and low rates of stem increment. Together with other factors such as water availability these patterns may contribute to an explanation of the diverse tree species composition on Central European screes. Bodennährstoffangebot und Biomasseproduktion in einem Mischwald auf einem stark skeletthaltigen Standort und in einem benachbarten Buchenwald In den natürlichen Waldgesellschaften Mitteleuropas dominiert die Buche (Fagus sylvatica L.) über ein weites Spektrum an bodenchemischen Standortsbedingungen. Eine Ausnahme in Bezug auf die Buchendominaz bilden stark skeletthaltige Standorte, wie etwa Blockhalden, wo bis zu 10 Laubbaumarten gemeinsam vorkommen. In solch einem Tilia-Fagus-Fraxinus-Acer-Ulmus -Wald und einem benachbarten Buchenreinbestand haben wir (1) die Bodennährstoffvorräte und Stickstoffmineralisationsraten, (2) den Blattnährstoffstatus und (3) die Blattproduktion und die Stammzuwachsraten vergleichend untersucht, um die Beziehung zwischen den Bodenbedingungen und der Baumartenzusammensetzung zu charakterisieren. In dem Mischwald fanden wir nur eine geringe Menge an Feinboden (35 g l,1), die sich in Taschen zwischen den Basaltsteinen befand, wohingegen ein signifikant (P < 0.05) höherer Gehalt an Feinboden (182 g l,1) in dem Buchenwald vorhanden war. In den Bodentaschen des Mischwaldes waren die C- und N-Konzentrationen und auch die Konzentrationen an austauschbar gebundenem K, Ca und Mg signifikant höher als im Buchenwald. Die Netto-N-Mineralisation pro Gewichtseinheit im Mischwald überstieg diejenige im Buchenwald um den Faktor 2,6. Wegen der unterschiedlichen Anteile an Feinboden und Skelett waren der volumenbezogene K-Vorrat und die volumenbezogene N-Mineralisationsrate im Mischwald (52 kg N ha,1 yr,1, 0,10 cm Tiefe) geringer als im Buchenwald (105 kg N ha,1 yr,1). Die Blattnährstoffgehalte von Buchen unterschieden sich zwischen den beiden Beständen nicht signifikant, was darauf hinweist, dass die Pflanzenernährung nicht beeinträchtigt war. Der herbstliche Blattstreufall (11,%) und die Zuwachsraten der Stammquerflächen (52,%) waren im Mischwald geringer als im Buchenwald. Im Vergleich mit dem benachbarten Buchenwald wies der Mischwald somit einen geringen Gehalt an sehr ungleichmäßig verteiltem, nährstoffreichen Boden, geringere volumenbezogene K-Vorräte und N-Mineralisationsraten und geringe Stammzuwächse auf. Gemeinsam mit anderen Faktoren, wie etwa der Wasserverfügbarkeit, können diese Muster zu einer Erklärung der Baumartenvielfalt auf mitteleuropäischen Blockstandorten beitragen. [source]


A coupling element-based quad-band antenna structure for mobile terminals

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 6 2007
Juha Villanen
Abstract A novel internal coupling element-based antenna structure for quad-band mobile terminals is presented. The antenna structure comprises of two nonresonant coupling elements, a multi-resonant matching circuitry, and the chassis of the mobile terminal. The coupling elements occupy an extremely low volume of only 0.7 cm3, and they have a very low profile of only 4 mm. Despite of the low volume and low profile of the antenna structure, it can fulfill the bandwidth requirements of the GSM850/900 and GSM1800/PCS1900 systems with sufficiently high efficiency, thus making it a promising antenna candidate for future mobile terminals. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1277,1282, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22463 [source]


Clinical findings in congenital absence of the vasa deferentia

ANDROLOGIA, Issue 1 2000
Dr W.-H.
Summary. In a clinical study, 105 patients with congenital bilateral absence of the vas deferens (CBAVD) and 18 with congenital unilateral absence of the vas deferens (CUAVD) were investigated. CUAVD was observed on the left side in 66%. Renal agenesis was more frequent in CUAVD (73.7%) than in CBAVD (11.8%). The leading signs of CBAVD are low pH level (average 6.5) and low volume of the ejaculate (average 0.95 ml). Testicular biopsies of 52 patients revealed normal spermatogenesis or hypospermatogenesis (33% in CBAVD; 45% in CUAVD). Genetic probing and counselling concerning cystic fibrosis are necessary if extracorporal microfertilization is considered. The absence of the vas deferens was often overlooked by the first investigator, the average time until correct diagnosis being 4.3 years. As artificial reproduction technology becomes more common, detection of vasal agenesis will certainly be made earlier and more frequently in the future. In order to assure compatibility of subsequent prospective studies about CBAVD and CUAVD, the following investigations are considered to be necessary: (i) semen analysis (pH, volume); (ii) renal ultrasonography or excretory urogram (screening for renal agenesis); (iii) genetic cystic fibrosis screening. [source]


Impacts of grazing, selective logging and hyper-aggressors on diurnal bird fauna in intact forest landscapes of the Brigalow Belt, Queensland

AUSTRAL ECOLOGY, Issue 6 2009
TERESA J. EYRE
Abstract The impact of forest management on diurnal bird assemblages and abundance was investigated in contiguous tracts of eucalypt forest in the Brigalow Belt Bioregion, south central Queensland. Sites were located across three levels of livestock grazing intensity and three levels of selective logging intensity within the most extensive habitat type, Corymbia citriodora -dominant forest. We recorded a high rate of incidence and large numbers of the hyper-aggressive noisy miner Manorina melanocephala (Passeriformes: Meliphagidae) at the majority of our survey sites, a phenomenon rarely reported in non-cleared landscapes. As shown by numerous studies in fragmented landscapes, the distribution of this species in our study had a substantial negative effect upon the distribution of small passerine species. Noisy miners exerted the strongest influence upon small passerine abundance, and masked any forest management effects. However, key habitat features important for small passerines were identified, including a relatively high density of large trees and stems in the midstorey. Selective logging appeared to exert a minimal effect upon noisy miner abundance, whereas grazing intensity had a profound, positive influence. Noisy miners were most abundant in intensively grazed forest with minimal midstorey and a low volume of coarse woody debris. Higher road density in the forest landscape also corresponded with increased numbers of noisy miners. Reduction in grazing pressure in Brigalow Belt forests has the potential to benefit small passerine assemblages across large areas through moderating noisy miner abundance. The strong relationship between noisy miners and small passerines suggests that noisy miner abundance could act as an easily measured indicator of forest condition, potentially contributing to monitoring of forest management outcomes. [source]


The relation between implied and realised volatility in the Danish option and equity markets

ACCOUNTING & FINANCE, Issue 3 2001
Charlotte Strunk Hansen
We show that the conclusions to be drawn concerning the informational efficiency of illiquid options markets depend critically on whether one carefully recognises and appropriately deals with the econometrics of the errors-in-variables problem. This paper examines the information content of options on the Danish KFX share index. We consider the relation between the volatility implied in an option's price and the subsequently realised index return volatility. Since these options are traded infrequently and in low volumes, the errors-in-variables problem is potentially large. We address the problem directly using instrumental variables techniques. We find that when measurement errors are controlled for, call option prices even in this very illiquid market contain information about future realised volatility over and above the information contained in historical volatility. [source]


Do Rural Elders Have Limited Access to Medicare Hospice Services?

JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 5 2004
Beth A. Virnig PhD
Objectives:, To examine whether there are urban-rural differences in use of the Medicare hospice benefit before death and whether those differences suggest that there is a problem with access to hospice care for rural Medicare beneficiaries. Design:, Observational study using 100% of Medicare enrollment, hospice, and hospital claims data. Setting:, Inpatient hospitals and hospices. Participants:, Persons aged 65 and older in the Medicare program who died in 1999. Measurements:, Rates of hospice use before death and in-hospital death rates were calculated. Results:, In 1999, there were 1.76 million deaths of Medicare beneficiaries aged 65 and older. Hospice services were used by 365,700 of these beneficiaries. Rates of hospice care before death were negatively associated with degree of rurality. The lowest rate of hospice use, 15.2% of deaths, was seen in rural areas not adjacent to an urban area. The highest rate of use, 22.2% of deaths, was seen in urban areas. Rural areas adjacent to urban areas had an intermediate level of hospice use (17.0% of deaths). Hospices based in rural areas had a smaller number of elderly patients each year than hospices based in urban areas (P<.001) and were more likely to have very low volumes (average daily census of three patients or less). Conclusion:, The consistently lower use of Medicare hospice services before death and smaller sizes of rural hospices suggest that the combination of Medicare hospice payment policies and hospice volumes are problematic for rural hospices. Adjusting Medicare payment policies might be a critical step to assure availability of hospice services forterminally ill beneficiaries regardless of where they live. [source]


The fruit fly PUB: a phagostimulation unit bioassay system to quantitatively measure ingestion of baits by individual flies

JOURNAL OF APPLIED ENTOMOLOGY, Issue 9-10 2004
D. Nestel
Abstract:, A bioassay to investigate quantitative phagostimulation and ingestion physiology of baits on individual fruit flies is presented. The study was undertaken using two fruit fly species: the Mediterranean fruit fly (Ceratitis capitata), a cosmopolitan insect pest, and the Ethiopian fruit fly (Dacus ciliatus), a quarantine insect in Israel. Our model bait suspension included spinosad as the toxic agent, and 1% yeast hydrolysate with 10% sucrose as phagostimulant. A preliminary toxicology study showed that the two fruit flies are highly sensitive to low concentrations of spinosad baited with this phagostimulant. The maximum concentration needed to kill 90% of the female flies was 4.2 and 8.5 p.p.m. for C. capitata and D. ciliatus, respectively. The bioassay was able to detect the ingestion of low volumes (e.g. 1 ,l) of tested solutions. The bioassay was also able to detect differences in intake of different concentrations of spinosad solutions and relate ingestion to fruit fly mortality. Additionally, the bioassay was sensitive enough to highlight differences in intake related to the physiological status of the fruit fly and fly species. The bioassay can also be used to follow ingestion kinetics of baits. We expect that this bioassay will contribute in the exploration of more efficient bait systems for fruit flies. [source]


Orogenic Gold Mineralization in the Qolqoleh Deposit, Northwestern Iran

RESOURCE GEOLOGY, Issue 3 2007
Farhang Aliyari
Abstract The Qolqoleh gold deposit is located in the northwestern part of the Sanandai-Sirjan Zone, northwest of Iran. Gold mineralization in the Qolqoleh deposit is almost entirely confined to a series of steeply dipping ductile,brittle shear zones generated during Late Cretaceous,Tertiary continental collision between the Afro-Arabian and the Iranian microcontinent. The host rocks are Mesozoic volcano-sedimentary sequences consisting of felsic to mafic metavolcanics, which are metamorphosed to greenschist facies, sericite and chlorite schists. The gold orebodies were found within strong ductile deformation to late brittle deformation. Ore-controlling structure is NE,SW-trending oblique thrust with vergence toward south ductile,brittle shear zone. The highly strained host rocks show a combination of mylonitic and cataclastic microstructures, including crystal,plastic deformation and grain size reduction by recrystalization of quartz and mica. The gold orebodies are composed of Au-bearing highly deformed and altered mylonitic host rocks and cross-cutting Au- and sulfide-bearing quartz veins. Approximately half of the mineralization is in the form of dissemination in the mylonite and the remainder was clearly emplaced as a result of brittle deformation in quartz,sulfide microfractures, microveins and veins. Only low volumes of gold concentration was introduced during ductile deformation, whereas, during the evident brittle deformation phase, competence contrasts allowed fracturing to focus on the quartz,sericite domain boundaries of the mylonitic foliation, thus permitting the introduction of auriferous fluid to create disseminated and cross-cutting Au-quartz veins. According to mineral assemblages and alteration intensity, hydrothermal alteration could be divided into three zones: silicification and sulfidation zone (major ore body); sericite and carbonate alteration zone; and sericite,chlorite alteration zone that may be taken to imply wall-rock interaction with near neutral fluids (pH 5,6). Silicified and sulfide alteration zone is observed in the inner parts of alteration zones. High gold grades belong to silicified highly deformed mylonitic and ultramylonitic domains and silicified sulfide-bearing microveins. Based on paragenetic relationships, three main stages of mineralization are recognized in the Qolqoleh gold deposit. Stage I encompasses deposition of large volumes of milky quartz and pyrite. Stage II includes gray and buck quartz, pyrite and minor calcite, sphalerite, subordinate chalcopyrite and gold ores. Stage III consists of comb quartz and calcite, magnetite, sphalerite, chalcopyrite, arsenopyrite, pyrrhotite and gold ores. Studies on regional geology, ore geology and ore-forming stages have proved that the Qolqoleh deposit was formed in the compression,extension stage during the Late Cretaceous,Tertiary continental collision in a ductile,brittle shear zone, and is characterized by orogenic gold deposits. [source]


Ultrasonographic guided axillary plexus blocks with low volumes of local anaesthetics: a crossover volunteer study

ANAESTHESIA, Issue 3 2010
P. Marhofer
Summary Our study group recently evaluated an ED95 local anaesthetic volume of 0.11 ml.mm,2 cross-sectional nerve area for the ulnar nerve. This prospective, randomised, double-blind crossover study investigated whether this volume is sufficient for brachial plexus blocks at the axillary level. Ten volunteers received an ultrasonographic guided axillary brachial plexus block either with 0.11 (,low' volume) or 0.4 (,high' volume) ml.mm,2 cross-sectional nerve area with mepivacaine 1%. The mean (SD) volume was in the low volume group 4.0 (1.0) and 14.8 (3.8) ml in the high volume group. The success rate for the individual nerve blocks was 27 out of 30 in the low volume group (90%) and 30 out of 30 in the high volume group (100%), resulting in 8 out of 10 (80%) vs 10 out of 10 (100%) complete blocks in the low vs the high volume groups, respectively (NS). The mean (SD) sensory onset time was 25.0 (14.8) min in the low volume group and 15.8 (6.8) min in the high volume group (p < 0.01). The mean (SD) duration of sensory block was 125 (38) min in the low volume group and 152 (70) min in the high volume group (NS). This study confirms our previous published ED95 volume for mepivacaine 1% to block peripheral nerves. The volume of local anaesthetic has some influence on the sensory onset time. [source]


Preclinical pharmacokinetics and metabolism of 6-(4-(2,5-difluorophenyl)oxazol-5-yl)-3-isopropyl-[1,2,4]-triazolo[4,3- a]pyridine, a novel and selective p38, inhibitor: identification of an active metabolite in preclinical species and human liver microsomes

BIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 8 2006
Amit S. Kalgutkar
Abstract The disposition of 6-(4-(2,5-difluorophenyl)oxazol-5-yl)-3-isopropyl-[1,2,4]-triazolo[4,3- a]pyridine (1), a potent and selective inhibitor of mitogen activated protein (MAP) kinase p38,, was characterized in several animal species in support of its selection for preclinical safety studies and potential clinical development. 1 demonstrated generally favorable pharmacokinetic properties in all species examined. Following intravenous (i.v.) administration, 1 exhibited low volumes of distribution at steady state (Vdss) ranging from 0.4,1.3 l/kg (2.4,26 l/m2) in the rat, dog and monkey. Systemic plasma clearance was low in cynomolgus monkeys (6.00 ml/min/kg, 72.0 ml/min/m2) and Sprague-Dawley rats (7.65±1.08 ml/min/kg, 45.9±6.48 ml/min/m2 in male rats and 3.15±0.27 ml/min/kg, 18.9±1.62 ml/min/m2 in female rats) and moderate in beagle dogs (12.3±5.1 ml/min/kg, 246±102 ml/min/m2) resulting in plasma half-lives ranging from 1 to 5 h in preclinical species. Moderate to high bioavailability of 1 was observed in rats (30,65%), dogs (87%) and monkeys (40%) after oral (p.o.) dosing consistent with the in vitro absorption profile of 1 in the Caco-2 permeability assay. In rats, the oral pharmacokinetics were dose dependent over the dose range studied (5, 50 and 100 mg/kg). The principal route of clearance of 1 in rat, dog, monkey and human liver microsomes and in vivo in preclinical species involved oxidative metabolism mediated by cytochrome P450 enzymes. The major metabolic fate of 1 in preclinical species and humans involved hydroxylation on the isopropyl group to yield the tertiary alcohol metabolite 2. In human liver microsomes, this transformation was catalysed by CYP3A4 as judged from reaction phenotyping analysis using isozyme-specific inhibitors and recombinant CYP enzymes. Metabolite 2 was also shown to possess inhibitory potency against p38, in a variety of in vitro assays. 1 as well as the active metabolite 2 were moderately to highly bound to plasma proteins (fu,0.1,0.33) in rat, mouse, dog, monkey and human. 1 as well as the active metabolite 2 did not exhibit competitive inhibition of the five major cytochrome P450 enzymes namely CYP1A2, 2C9, 2C19, 2D6 and 3A4 (IC50>50 µM). Overall, these results indicate that the absorption, distribution, metabolism and excretion (ADME) profile of 1 is relatively consistent across preclinical species and predict potentially favorable pharmacokinetic properties in humans, supporting its selection for toxicity/safety assessment studies and possible investigations in humans as an anti-inflammatory agent. Copyright © 2006 John Wiley & Sons, Ltd. [source]


Ultrasonographic guided axillary plexus blocks with low volumes of local anaesthetics: a crossover volunteer study

ANAESTHESIA, Issue 3 2010
P. Marhofer
Summary Our study group recently evaluated an ED95 local anaesthetic volume of 0.11 ml.mm,2 cross-sectional nerve area for the ulnar nerve. This prospective, randomised, double-blind crossover study investigated whether this volume is sufficient for brachial plexus blocks at the axillary level. Ten volunteers received an ultrasonographic guided axillary brachial plexus block either with 0.11 (,low' volume) or 0.4 (,high' volume) ml.mm,2 cross-sectional nerve area with mepivacaine 1%. The mean (SD) volume was in the low volume group 4.0 (1.0) and 14.8 (3.8) ml in the high volume group. The success rate for the individual nerve blocks was 27 out of 30 in the low volume group (90%) and 30 out of 30 in the high volume group (100%), resulting in 8 out of 10 (80%) vs 10 out of 10 (100%) complete blocks in the low vs the high volume groups, respectively (NS). The mean (SD) sensory onset time was 25.0 (14.8) min in the low volume group and 15.8 (6.8) min in the high volume group (p < 0.01). The mean (SD) duration of sensory block was 125 (38) min in the low volume group and 152 (70) min in the high volume group (NS). This study confirms our previous published ED95 volume for mepivacaine 1% to block peripheral nerves. The volume of local anaesthetic has some influence on the sensory onset time. [source]