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Minute Amounts (minute + amount)

Distribution by Scientific Domains

Medical Sciences	35%
Life Sciences	23%
Chemistry	23%

Selected Abstracts

Minute amounts of intraarticular gas mimicking torn discoid lateral menisci

JOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 3 2010
Martin I. Jordanov MD
Abstract Presented are two cases of minute amounts of vacuum phenomena within the central portion of the lateral compartments of two knee joints, mimicking torn discoid lateral menisci. In each case, only the gradient echo images were able to correctly characterize the minute quantities of intraarticular gas by demonstrating "blooming" magnetic susceptibility artifact. The signal characteristics of the intraarticular gas were identical to those of fibrocartilage on all of the remaining routine, fast spin echo, "sports protocol" magnetic resonance imaging sequences. J. Magn. Reson. Imaging 2010;31:698,702. © 2010 Wiley-Liss, Inc. [source]

Effects of macromolecular impurities and of crystallization method on the quality of eubacterial aspartyl-tRNA synthetase crystals

ACTA CRYSTALLOGRAPHICA SECTION D, Issue 6 2005
A. Moreno
Although macromolecular purity is thought to be essential for the growth of flawless protein crystals, only a few studies have investigated how contaminants alter the crystallization process and crystal quality. Likewise, the outcome of a crystallization process may vary with the crystallization method. Here, it is reported how these two variables affect the crystallogenesis of aspartyl-tRNA synthetase from the eubacterium Thermus thermophilus. This homodimeric enzyme (Mr = 130,000) possesses a multi-domain architecture and crystallizes either in a monoclinic or an orthorhombic habit. Minute amounts of protein impurities alter to a different extent the growth of each crystal form. The best synthetase crystals are only obtained when the crystallizing solution is either enclosed in capillaries or immobilized in agarose gel. In these two environments convection is reduced with regard to that existing in an unconstrained solution. [source]

Injecting 1000 Centistoke Liquid Silicone With Ease and Precision

DERMATOLOGIC SURGERY, Issue 3 2003
Anthony V. Benedetto DO, FACP
BACKGROUND Since the Food and Drug Administration approved the use of the 1000 centistoke liquid silicone, Silikon 1000, for intraocular injection, the off-label use of this injectable silicone oil as a permanent soft-tissue filler for facial rejuvenation has increased in the United States. Injecting liquid silicone by the microdroplet technique is the most important preventive measure that one can use to avoid the adverse sequelae of silicone migration and granuloma formation, especially when injecting silicone to improve small facial defects resulting from acne scars, surgical procedures, or photoaging. OBJECTIVE To introduce an easy method for injecting a viscous silicone oil by the microdroplet technique, using an inexpensive syringe and needle that currently is available from distributors of medical supplies in the United States. METHOD We suggest the use of a Becton Dickinson 3/10 cc insulin U-100 syringe to inject Silikon 1000. This syringe contains up to 0.3 mL of fluid, and its barrel is clearly marked with an easy-to-read scale of large cross-hatches. Each cross-hatch marking represents either a unit value of 0.01 mL or a half-unit value of 0.005 mL of fluid, which is the approximate volume preferred when injecting liquid silicone into facial defects. Because not enough negative pressure can be generated in this needle and syringe to draw up the viscous silicone oil, we describe a convenient and easy method for filling this 3/10 cc diabetic syringe with Silikon 1000. RESULTS We have found that by using the Becton Dickinson 3/10 cc insulin U-100 syringe, our technique of injecting minute amounts of Silikon 1000 is facilitated because each widely spaced cross-hatch on the side of the syringe barrel is easy to read and measures exact amounts of the silicone oil. These lines of the scale on the syringe barrel are so large and clearly marked that it is virtually impossible to overinject the most minute amount of silicone. CONCLUSION Sequential microdroplets of 0.01 cc or less of Silikon 1000 can be measured and injected with the greatest ease and precision so that inadvertent overdosing and complications can be avoided. [source]

Iodide-Selective Electrode Based on Copper Phthalocyanine

ELECTROANALYSIS, Issue 23 2002
Saeed Shahrokhian
Abstract Copper phthalocyanine was used as ion carrier for preparing polymeric membrane selective sensor for detection of iodide. The electrode was prepared by incorporating the ionophore into plasticized poly(vinyl chloride) (PVC) membrane, coated on the surface of graphite electrode. This novel electrode shows high selectivity for iodide with respect to many common inorganic and organic anions. The effects of membrane composition, pH and the influence of lipophilic cationic and anionic additives and also nature of plasticizer on the response characteristics of the electrode were investigated. A calibration plot with near-Nernestian slope for iodide was observed over a wide linear range of five decades of concentration (5×10,6,1×10,1,M). The electrode has a fast response time, and micro-molar detection limit (ca. 1×10,6,M iodide) and could be used over a wide pH range of 3.0,8.0. Application of the electrode to the potentiometric titration of iodide ion with silver nitrate is reported. This sensor is used for determination of the minute amounts of iodide in lake water samples. [source]

Electrophoretically mediated microanalysis for the evaluation of interspecies variation in cholinesterase metabolism

ELECTROPHORESIS, Issue 14 2010
Joana Moura
Abstract This study describes an electrophoretically mediated microanalysis method, suitable for the preclinical evaluation of the hydrolysis of ester drugs by the serum of different animals and for further characterization of human,animal correlation. Dog, cat, cow, horse, sheep, rat and human serum were diluted (25%) in the appropriate buffer and replaced the enzyme solution usually used in electrophoretically mediated microanalysis methods for the study of enzyme kinetics. They were then compared in terms of the ability to hydrolyze acetylthiocholine and butyrylthiocholine (0.25,mM) by in-capillary reaction. Human serum afforded the highest conversion rates (52% butyryltiocholine and 34% acetylthiocholine) followed by horse (31 and 35%), dog (26 and 24%), cat (22 and 14%), rat (11 and 15%) and sheep (8 and 8%). Hydrolysis by bovine serum was negligible. The method is fast (under 8,min including rinsing steps), sensitive (under 25,,M substrate could be quantified) and repeatable (RSD,2%), only requiring minute amounts of sample. [source]

Determination of amino acids by micellar EKC: Recent advances in method development and novel applications to different matrices

ELECTROPHORESIS, Issue 1 2008
Paolo Iadarola Professor
Abstract The extensive use of CE for the analysis of amino acids has been well documented in a series of research articles and reviews. Aim of this report is to address the attention of the reader on the recent advances of micellar electrokinetic chromatography for the separation and determination of these analytes. Enhancements in selectivity of this technique through the use of pseudostationary phases containing mixed micelles, polymers, and chiral selectors are presented. Selected applications concerning separation and quantitation of even minute amounts of amino acids in: (i) biological fluids; (ii) microdialysates; (iii) plant cells; (iv) food stuff; and (v) pharmaceutical formulations have also been covered. Advantages of MEKC over other techniques for the amino acid analysis have been underlined. [source]

Biomimetic Carbonate,Hydroxyapatite Nanocrystals Prepared by Vapor Diffusion,

ADVANCED ENGINEERING MATERIALS, Issue 7 2010
Michele Iafisco
Abstract Biomimetic carbonate,hydroxyapatite (HA) nanocrystals have been synthesized by using the sitting drop vapor diffusion technique, for the first time. The method consists of diffusing vapors of an aqueous solution of NH4HCO3 through drops containing an aqueous mixture of (CH3COO)2Ca and (NH4)2HPO4 in order to increase slowly their pH. This synthesis has been performed in a crystallization mushroom, a glass device developed for protein and small molecules crystallization. The concentrations of the reagents, the final pH and the crystallization time have been optimized to produce pure carbonate,HA as a single phase. X-Ray diffraction, Fourier transformed infrared spectroscopy, and transmission electron microscopy have been utilized to characterize the synthesized carbonated substituted HA crystals which display nanometric dimensions, plate-like morphology, and low crystallinity degree, closely resembling the inorganic phase of bones, teeth, and many pathological calcifications. This novel method may prove to be suitable for the study of the interactions and/or the co-crystallization of hydroxyapatite with minute amounts of biomolecules, polymers, or drugs. [source]

Detection of drug-resistant HIV minorities in clinical specimens and therapy failure

HIV MEDICINE, Issue 3 2008
S Louvel
Objective Particularly for therapy-experienced patients, resistance assessment by genotypic or phenotypic methods produces discordances. This study seeks proof that differences may arise from the fact that genotyping produces a single summary sequence whereas replicative phenotyping (rPhenotyping) functionally detects and assigns resistances in mixed HIV populations. Methods For validation, defined mixes of wild-type and M184V mutant were analysed by rPhenotyping or standard genotyping. Allele-specific and quantitative polymerase chain reaction (PCR) set detection and quantification limits for minor virus populations in vitro and in authentic clinical samples showing geno-/pheno-discrepant lamivudine resistance. Results Allele-specific and real-time PCR methods detected down to 0.3% of mutant M184V. The functional assessment was sensitive enough to reveal <1% of mutant M184V in mixed samples. Also in discordant samples from the diagnostic routine, in which rPhenotyping had identified drug resistance, real-time PCR confirmed minute amounts of mutant M184V. Conclusion By utilizing the replication dynamics of HIV under drug pressure, a rPhenotyping format potently reveals relevant therapy-resistant minority species, even of HIV known to possess reduced replicative fitness. With its rapid turnaround of 8 days and its high sensitivity, our rPhenotyping system may be a valuable diagnostic tool for detecting the early emergence of therapy-threatening HIV minorities or the persistence of residual resistant virus. [source]

Development and design of a ,ready-to-use' reaction plate for a PCR-based simultaneous detection of animal species used in foods

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 1 2007
Ines Laube
Summary Different TaqManTM -polymerase chain reaction systems have been developed, which allow the detection of even minute amounts of beef, pork, lamb, goat, chicken, turkey and duck in processed foods. The species-specific systems are able to amplify DNA regions with no more than 108 bp in size (exception: duck, 212 bp) located on the single-copy genes cyclic guanosine monophosphate (cyclic GMP) phosphodiesterase, ryanodine receptor and interleukin -2 precursor. The parallel detection of the common ingredient ,meat' produced from mammals and poultry was based on the amplification of a region of the myostatin gene. The limit of detection was determined to be ten genome copies for each system. The relative SD under repeatability condition was below 30%. In addition, a ,ready-to-use' reaction plate has been developed, which makes it possible to investigate the presence of the seven animal species in parallel after a single real-time run. [source]

Minute amounts of intraarticular gas mimicking torn discoid lateral menisci

Major differences in bleeding symptoms between factor VII deficiency and hemophilia B

JOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 5 2009
F. BERNARDI
Summary.,Background:,The autosomally-inherited factor VII (FVII) deficiency and X-linked hemophilia B offer an attractive model to investigate whether reduced levels of FVII and FIX, acting in the initiation and amplification of coagulation respectively, influence hemostasis to a different extent in relation to age and bleeding site. Methods:,Hemophilia B patients (n = 296) and FVII-deficient males (n = 109) were compared for FVII/FIX clotting activity, F7/F9 genotypes and clinical phenotypes in a retrospective, multi-centre, cohort study. Results:,Major clinical differences between diseases were observed. Bleeding occurred earlier in hemophilia B (median age 2.0 years, IR 0.9,5.0) than in FVII deficiency (5.2 years, IR 1.9,15.5) and the bleeding-free survival in FVII deficiency was similar to that observed in ,mild' hemophilia B (P = 0.96). The most frequent disease-presenting symptoms in hemophilia B (hematomas and oral bleeding) differed from those in FVII deficiency (epistaxis and central nervous system bleeding). Differences were confirmed by analysis of FVII-deficient women. Conclusions:,Our data support the notion that low FVII levels sustain hemostasis better than similarly reduced FIX levels. On the other hand, minute amounts of FVII, differently to FIX, are needed to prevent fatal bleeding, as indicated by the rarity of null mutations and the associated life-threatening symptoms in FVII deficiency, which contributes towards shaping clinical differences between diseases in the lowest factor level range. Differences between diseases are only partially explained by mutational patterns and could pertain to the specific roles of FVII and FIX in coagulation phases and to vascular bed-specific components. [source]

Geochemical identification of projectiles in impact rocks

METEORITICS & PLANETARY SCIENCE, Issue 11 2006
Roald Tagle
The identification of a projectile component in impactites can be achieved by determining certain isotopic and elemental ratios in contaminated impactites. The isotopic methods are based on Os and Cr isotopic ratios. Osmium isotopes are highly sensitive for the detection of minute amounts of extraterrestrial components of even <<0.05 wt% in impactites. However, this only holds true for target lithologies with almost no chemical signature of mantle material or young mantle-derived mafic rocks. Furthermore, this method is not currently suitable for the precise identification of the projectile type. The Cr-isotopic method requires the relatively highest projectile contamination (several wt%) in order to detect an extraterrestrial component, but may allow the identification of three different groups of extraterrestrial materials, ordinary chondrites, an enstatite chondrites, and differentiated achondrites. A significant advantage of this method is its independence of the target lithology and post-impact alteration. The use of elemental ratios, including platinum group elements (PGE: Os, Ir, Ru, Pt, Rh, Pd), in combination with Ni and Cr represents a very powerful method for the detection and identification of projectiles in terrestrial and lunar impactites. For most projectile types, this method is almost independent of the target composition, especially if PGE ratios are considered. This holds true even in cases of terrestrial target lithologies with a high component of upper mantle material. The identification of the projectile is achieved by comparison of the "projectile elemental ratio" derived from the slope of the mixing line (target-projectile) with the elemental ratio in the different types of possible projectiles (e.g., chondrites). However, this requires a set of impactite samples of various degree of projectile contamination. [source]

Pollination biology of the sclerophyllous shrub Pultenaea villosa Willd. (Fabaceae) in southeast Queensland, Australia

PLANT SPECIES BIOLOGY, Issue 1 2009
JANE E. OGILVIE
Abstract The pollination biology of the common shrub Pultenaea villosa Willd. was examined in a subtropical dry sclerophyll forest in eastern Australia. We determined floral phenology and morphology, the timing of stigma receptivity and anther dehiscence, nectar availability, the plant breeding system, and flower visitors. The shrub's flowers are typical zygomorphic pea flowers with hidden floral rewards and reproductive structures. These flowers require special manipulation for insect access. A range of insects visited the flowers, although bees are predicted to be the principle pollinators based on their frequency on the flowers and their exclusive ability to operate the wing and keel petals to access the reproductive structures. Nectar and pollen are offered as rewards and were actively collected by bees. Nectar is offered to visitors in minute amounts at the base of the corolla. In Toohey Forest, P. villosa flowers in spring and is the most abundant floral resource in the understory of the forest at this time. The breeding system experiment revealed that P. villosa requires outcrossing for high levels of seed set and that the overlap of stigma receptivity and pollen dehiscence within the flower suggests the potential for self-incompatibility. [source]

Short-term dietary supplementation with the microalga Parietochloris incisa enhances stress resistance in guppies Poecilia reticulata

AQUACULTURE RESEARCH, Issue 2 2010
Anurag Dagar
Abstract Two trials were conducted to determine the effects of dietary enrichments with the microalga Parietochloris incisa, rich in arachidonic acid (ARA), on stress resistance in guppies Poecilia reticulata. The microalga was added to commercial diets as a neutral lipid (NL) extract and its fractions or as broken cells. Experimental diets were applied for a period of 14 days. In trial 1, commercial diets were supplemented with NL (containing 25 mg ARA and 0.11 mg ,-carotene g,1 feed), its triacylglycerol (TAG) fraction (containing 25 mg ARA g,1 feed and no ,-carotene) and the ,-carotene fraction (containing 0.11 mg carotenoid g,1 feed and minute amounts of ARA). Neutral lipid-fed fish demonstrated the highest resistance (P<0.05) to osmotic stress (32-ppt NaCl), followed by fish fed with diets supplemented with TAG and ,-carotene alone, which were more resistant than control (P<0.05). In trial 2, fish fed diets supplemented with higher levels of broken alga (26.1 mg ARA g,1 feed) were more resistant (P<0.05) to stress as compared with fish fed lower ARA (16.3 mg g g,1) or an unsupplemented control diet. We suggest a dietary supplementation with broken P. incisa cells to enhance stress resistance in guppies before a stressful event. [source]

Studies on the endogenous phospholipids of chick embryo myocardium and their in vitro hydrolysis by endogenous phospholipases during embryogenesis

CELL BIOCHEMISTRY AND FUNCTION, Issue 5 2007
Fatma M. Helmy
Abstract The phospholipid profiles of the myocardium (from 10- and 18-day old chick embryos and 13-day old chick) and their in vitro response to the endogenous lipolytic enzymes (mainly of the phospholipase group) at pH 7.4 and 38°C for 60,min were analyzed by TLC technology and densitometry. Cardiolipin (CL) was shown to be one of the major phospholipids of the chick embryo myocardium and its concentration increased as the chick embryo advanced in development. Monolysocardiolipin (MLCL) was produced subsequent to in vitro incubation of whole tissue homogenates in all myocardia studied as well as a concurrent reduction in CL. This deacylation of CL increased in magnitude as the chick embryo advanced in development indicating its age relatedness. The level of phosphatidyl ethanolamine (PE) plasmalogen was also high in all myocardia studied. Lyso alkenyl PE (LPE) was produced subsequent to in vitro incubation and its level increased as the chick embryo advanced in development, indicating PLA2 action on the sn-2 fatty acid of PE. Phosphatidyl choline (PC) plasmalogen was also present in the chick embryo myocardium and its level increased gradually as the chick embryo advanced in development. In contrast, yolk-sac membrane contains very minute amounts of CL and PE. No PC was detected and no LPE was formed following in vitro incubation. The yolk of the unfertilized chicken egg has no CL and has very minute amounts of PE, no PC and no lysophospholipids were detected following in vitro incubation in all samples analyzed. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Identification and Biosynthesis of an Aggregation Pheromone of the Storage Mite Chortoglyphus arcuatus

CHEMBIOCHEM, Issue 11 2004
Stefan Schulz Prof.
Abstract In an effort to identify new pheromones from mites, the headspace of undisturbed colonies of the storage mite Chortoglyphus arcuatus was analyzed by GC-MS by use of a closed-loop stripping apparatus (CLSA) or solid-phase microextraction (SPME). The major compound emitted from the mites is (4R,6R,8R)-4,6,8-trimethyldecan-2-one (4R,6R,8R - 8). The structure was elucidated by analysis of the mass spectrum, synthesis of authentic samples, and gas chromatography on a chiral phase. Bioassays show that this compound, for which we propose the trivial name chortolure, is an aggregation pheromone for both sexes of this species. Several related compounds are released in smaller amounts by the mites. The alarm pheromones of these mites, neral and geranial, can only be found in total extracts of the mites, in which 8 occurs only in minute amounts. The method of sampling is therefore crucial for pheromone identification. Feeding experiments with deuterated propionate showed that chortolure is a polyketide, formed by successive addition of four propionate units to an acetate starter. [source]