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Different Concentrations (different + concentration)
Terms modified by Different Concentrations Selected AbstractsGELLING BEHAVIOR OF RICE FLOUR DISPERSIONS AT DIFFERENT CONCENTRATIONS OF SOLIDS AND TIME OF HEATINGJOURNAL OF TEXTURE STUDIES, Issue 3 2008ALKA KAPRI ABSTRACT Rice flour dispersions, under suitable conditions of processing, can form a gel. The effect of concentration of solids (10,18%) and time (0,75 min) of processing on textural attributes, and viscoelasticity were investigated along with sensory attributes. The textural attribute determined is gel strength, while viscoelasticity was determined in terms of mechanical spectra like storage modulus (G,), loss modulus (G,), complex viscosity (,*) and loss factor (tan ,) during a frequency sweep varying from 0.01 to 40 Hz at a constant stress of 25 Pa. Microstructural observation indicates the swelling of starch granules in the beginning of heating, while damaged granule and leached-out materials are visible at the end of the gelling process. Desirability function analysis has been applied to obtain a rice gel with acceptable textural attributes; a solid concentration of 15.2% and a heating time of 75 min can lead to the development of a gel with a satisfaction level of 0.6. PRACTICAL APPLICATIONS Rice flour gels in the form of hard-set gels, porridges and spreads are popular in several parts of the world particularly for feeding of infants and children. The application of the present study lies in understanding the role of major processing variables on the quality attributes and viscoelasticity of a product, characterization of cooked gels and for developing rice flour-based food gels. The findings may also be extended for the development of other cereal-based gels. [source] Effect of Different Concentrations of Ascorbic Acid on Motility, Membrane Integrity and Chromatin Status of Frozen-Thawed Canine Spermatozoa Within Six Hours of Storage at 37°CREPRODUCTION IN DOMESTIC ANIMALS, Issue 2009K Eulenberger Contents The aim of this study was to examine comprehensively the effect of ascorbic acid (Asc) on frozen-thawed canine semen. Pooled ejaculates (n = 10) were assessed for quality with a computer-assisted sperm analyser (CASA). After centrifugation, the semen was divided into four aliquots (A,D) of which three were diluted with Uppsala 1 extender (v/v) containing different concentrations of Asc (B: 6.8 mmol/l; C: 13 mmol/l; D: 27 mmol/l). One group without Asc served as control (A). Subsequently, dilution samples were treated and cryopreserved as described previously (Theriogenology 66, 2006, 173). After thawing, samples were stored at 37°C for 1, 3 and 6 h, then examined for quality (CASA, flow cytometry, sperm chromatin structure assay; SCSA). Staining for flow cytometry was performed with FITC-PNA and propidium iodide (Reproduction 128, 2004, 829). The SCSA was performed with both Tris-NACL-EDT buffer (TNE)- and Tris-fructose-citrate buffer (TFC). In the Asc-supplemented groups, percentages of progressively motile sperm (P) were significantly lower than in the control group (A 1 h: 56.6 ± 9.8, 6 h: 18 ± 4.5; B 1 h: 51.2 ± 11.8, 6 h: 13.6 ± 5; C 1 h: 41 ± 16.2, 6 h: 11.2 ± 6.1; D 1 h: 37 ± 15.2, 6 h: 8.6 ± 5; p < 0.01), whereas, the percentages of intact cells without acrosome reactions did not differ between groups (p > 0.05). Furthermore, there were no significant differences between TNE- and TFC-samples, for ,T, for SD of ,T or for comp ,T [comp ,T: TCF-A: 2.5 ± 1.7%, TNE-A: 3.4 ± 3.2%; TCF-D: 2.5 ± 2%, TNE-D: 3.3 ± 4.3%; p > 0.05]. However, samples diluted with both extenders correlated concerning ,T, but not comp ,T. We therefore recommend using TNE-buffer for SCSA with cryopreserved canine semen. In addition, the average ,T values did not differ significantly between the controls and all other groups (TNE-A: 380.2 ± 89.1; TNE-D: 338.1 ± 137.4; p > 0.05). It can be concluded that addition of Asc to cryoextender does not increase quality of frozen-thawed canine semen. [source] Phenol-Castor Oil: Modified Peel for Dermal MelasmaDERMATOLOGIC SURGERY, Issue 5 2006THADA PIAMPHONGSANT MD BACKGROUND Deep type of melasma is difficult to treat. Various compositions for peeling have been formulated to accomplish this. OBJECTIVE Our purpose was to determine the safe use of the new formula, which was composed of phenol and castor oil. METHODS Different concentrations of phenol and castor oil were mixed in five formulations, and the solutions were tested on the forearms of 10 volunteers. The application time was 1 minute, different from that of the original phenol-croton oil. Formula 4 was found to cause a high effect of peeling with least side effects and was used to treat deep facial melasma in 30 patients. RESULTS Higher concentrations of castor oil produced more inflammation when mixed with phenol. Formula 4 was used to clear two cases of melasma in 1 week despite no effect from prior use of a modified antimelasma cream, while some degree of fading was noted in other cases. The total number of different melasma indices was reduced from 206.4 to 91.2 in 30 patients. Hyperpigmentation was noted in five cases and hypopigmentation in one case. Neither scar formation nor cardiac arrhythmia was observed. CONCLUSION A phenol-castor oil peel with an application time of 1 minute reduces pigments in the deep type of melasma with least side effects and a high efficiency when combined with an antimelasma cream. The safe formula and the technique of application are introduced. [source] Decolourisation of aqueous dyes by sequential oxidation treatment with ozone and Fenton's reagentJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 7 2002M Mahbubul Hassan Abstract Combined oxidation with ozone and Fenton's reagent (,Fentozone' process) for decolourisation of aqueous dyes was studied and compared with traditional Fenton's reagent. Although the ,Fentozone' process was found to be effective at a wide range of pH values, the maximum colour removal was achieved at pH 4. The effect of pre-ozonation on colour removal efficiency of aqueous dyestuffs in the subsequent treatment with Fenton's reagent was investigated. The reaction kinetics using water-soluble acid and reactive dyes were also studied. Our experimental results show that pre-ozonation can considerably accelerate decomposition of dyestuffs in the subsequent treatment with Fenton's reagent. Different concentrations of ferrous sulfate were used to investigate their influences on the removal of colour. The rate of reaction increased with increasing doses of ferrous sulfate. © 2002 Society of Chemical Industry [source] Stimulatory Effect of N -Methyltyramine, a Congener of Beer, on Pancreatic Secretion in Conscious RatsALCOHOLISM, Issue 2010Eri Tsutsumi Background:, Alcoholic beverages stimulate gastric acid secretion and increase the appetite. Although ingested ethanol stimulates pancreatic secretion, alcoholic beverages contain several congeners. N -methyltyramine (NMT) was isolated from beer as a factor in stimulating gastric acid secretion. In this study, we examined NMT to determine whether the congener stimulated pancreatic secretion in conscious rats. Methods:, Cannulae were inserted into male Wistar rats to separately drain bile and pancreatic secretions: 2 duodenal cannulae, a gastric cannula, and an external jugular vein cannula. The rats were placed in modified Bollman-type restraint cages. After a 4-day recovery period, experiments were conducted on unanesthetized rats. Different concentrations of NMT (5, 25, and 50 ,g/kg) solutions were infused into the stomach. To examine the mechanism, the effects of the proton pump inhibitor, cholecystokinin (CCK-BR) antagonist (YM022), CCK-AR antagonist (CR1505), and atropine were administered prior to the NMT (25 ,g/kg) infusion. The effect of intravenous infusion of NMT (7.5 ,g/kg) was then determined. Moreover, dispersed acini were prepared, and the effect of different concentrations of NMT on amylase release was determined. Results:, Intragastric administration of NMT significantly increased pancreatic exocrine secretion in a dose-dependent manner. Atropine eliminated the stimulatory effect of NMT, but the infusion of the proton pump inhibitor, YM022, and CR1505 did not. Intravenous infusion of NMT did not affect pancreatic secretion, and NMT did not stimulate amylase release in vitro. Conclusions:,N -methyltyramine stimulates pancreatic secretion via the cholinergic gastro-pancreatic reflex. The NMT content in beer was 2 mg/l, so that if a person weighing 60 kg consumes a 750 ml of beer, 25 ,g/kg NMT will be ingested. Therefore, the stimulatory effect of beer on pancreatic secretion was produced not only by ethanol but also by the congener, NMT. [source] The Effects of 5-Aminolevulinic Acid Esters on Protoporphyrin IX Production in Human Adenocarcinoma Cell Lines,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 5 2001H. Brunner ABSTRACT Photodynamic diagnosis (PDD) and photodynamic therapy (PDT) using 5-aminolevulinic acid (ALA),induced protoporphyrin IX (PPIX) is an interesting approach to detect and treat dysplasia and early cancers in the gastrointestinal tract. Because of low lipophilicity resulting in poor penetration across cell membranes, high doses of ALA should be administered in order to reach clinically relevant levels of PPIX. One way of increasing PPIX accumulation is derivatization of ALA into a more lipophilic molecule. In our in vitro study, different esterifications of ALA were investigated to analyze the effects on PPIX accumulation in human adenocarcinoma cell lines. For systematic analysis of cell type,specific PPIX accumulation, three human adenocarcinoma cell lines (SW480, HT29 and CaCo2) and a fibroblast cell line (CCD18) were tested. 3-(4,5-Dimethylthiazole-2-yl)-2,5-biphenyl tetrazolium bromide (MTT) assays were performed to ensure that the ALA esters showed no cellular dark toxicity. Different concentrations (ranging from 0.012 to 0.6 mmol/L, 3 h) and incubation times (5, 10, 30, 180 min; 0.12 mmol/L) were examined. PPIX accumulation was measured using flow cytometry. ALA esters, especially ALA-hexylester and ALA-benzylester, induced significant higher PPIX levels in adenocarcinoma cell lines when compared with ALA and may be promising candidates for PDT and PDD. [source] Melt strength of calcium carbonate filled polypropylene meltsPOLYMER INTERNATIONAL, Issue 12 2002Nhol Kao Abstract This paper investigates the extensional rheology (through melt strength measurement) of calcium carbonate (CaCO3) filled polypropylene (PP) melts. Different concentrations of CaCO3 filled PP were produced by mixing two master batches of pure PP and 70,wt% CaCO3 filled PP in required proportions in a counter-rotating twin-screw extruder. It was found that the melt strength of the CaCO3,PP melts was independent of CaCO3 concentrations up to 25,vol%. Further increase in CaCO3 concentration led to a severe reduction of melt strength. © 2002 Society of Chemical Industry [source] Lipid-enhanced pollen and lipid-reduced flour diets and their effect on the longevity of honey bees (Apis mellifera L.)AUSTRALIAN JOURNAL OF ENTOMOLOGY, Issue 3 2007Rob Manning Abstract, As eucalypt pollens contain low concentrations of lipid, enhancing pollen diets with fatty acids was hypothesised to improve honey bee longevity. Different concentrations of linoleic and oleic acid added to eucalypt pollen were trialled in small cages containing approximately 1400 bees each. Bees fed diets of redgum (Corymbia calophylla (Lindl.) Hill & Johnson, formerly Eucalyptus calophylla) pollen had the lowest mortality of 22 diets tested for 6 weeks and had life spans (50%) greater than 42 days. Linoleic acid mixed with a redgum diet in concentrations >6% corresponded to life spans of 24,25 days. Bee longevity appeared to be more sensitive to oleic acid as life spans decreased to 15,21 days when diets had concentrations >2%. The life spans of bees fed soya bean flour were 26 days on low (0.6% lipid) fat, 19 days on defatted and 20 days on full-fat diets. Bees fed lupin flour had a life span of 23 days. Adding redgum pollen to lupin flour caused increased mortality, but addition of pollen to soya bean flour was beneficial. Thus, beekeepers who choose to utilise soya bean or lupin flours as protein substitutes to pollen will have bees with reduced longevity. Bees fed redgum pollen that had been dried, crushed, irradiated and hermetically stored in a cool room for several years had similar longevity to bees fed fresh-collected and frozen redgum pollen. [source] Enhancement of in vitro and in vivo microdialysis recovery of SB-265123 using Intralipid® and Encapsin® as perfusatesBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 1 2003Keith W. Ward Abstract This study was conducted to compare the ability of two potential microdialysis perfusates to enhance the recovery of SB-265123, a lipophilic, highly protein-bound compound, both in vitro and in vivo. Initial in vitro experiments established that the recovery of SB-265123 by microdialysis using normal saline as a perfusate was poor (1.7%). Different concentrations of Intralipid® and Encapsin® also were evaluated in an identical in vitro setting, to determine enhancement of recovery. In vitro recovery was enhanced to approximately 24 and 65% with 5 and 20% Intralipid®, and to approximately 59 and 62% with 5 and 20% Encapsin®, respectively. A rat in vivo study was conducted with 20% Encapsin® to confirm the in vitro observations. In the in vivo study, 75,80% recovery of free SB-265123 was achieved using 20% Encapsin® as a perfusate. The results from this study indicate that for SB-265123, a lipophilic, highly protein-bound molecule, Encapsin® is an efficient recovery enhancer in vitro. The results from this investigation further demonstrate that a recovery enhancer may be useful for in vivo applications, even with a compound that is highly bound to plasma protein. Copyright © 2002 John Wiley & Sons, Ltd. [source] Polyethylenimine-coated albumin nanoparticles for BMP-2 deliveryBIOTECHNOLOGY PROGRESS, Issue 4 2008Sufeng Zhang Abstract Nanoparticle (NP)-based delivery has gained importance for improving the potency of therapeutic agents. The bovine serum albumin (BSA) NPs, obtained by a coacervation process, was modified by electrostatic adsorption of cationic polyethylenimine (PEI) to NP surfaces for delivery of bone-inducing growth factor, bone morphogenetic protein-2 (BMP-2). Different concentrations of PEI were utilized for coating BSA NPs to stabilize the colloidal system and to control the release of BMP-2. The NPs were characterized by size and zeta potential measurements, as well as by Scanning Electron Microscopy and Atomic Force Microscopy. The encapsulation efficiency was typically >90% in all NP preparations. In vitro release kinetics showed that the PEI concentration used for coating the NPs efficiently controlled the release of BMP-2, demonstrating a gradual slowing, sustained release pattern during a 10-day study period. The bioactivity of the encapsulated BMP-2 and the toxicity of the NPs were examined by the alkaline phosphatase (ALP) induction assay and the MTT assay, respectively, using C2C12 cells. The results indicated that PEI was the primary determinant of NP toxicities, and BSA NPs coated with 0.1 mg/mL PEI demonstrated tolerable toxicity, retained the bioactivity of BMP-2, and efficiently slowed the release rate of BMP-2. We conclude that BMP-2 encapsulated in BSA NPs might be an efficient way to deliver the protein for in vivo bone induction. [source] In vitro antifungal susceptibility patterns of dermatophyte strains causing tinea unguiumCLINICAL & EXPERIMENTAL DERMATOLOGY, Issue 6 2007E. Sarifakioglu Summary Background., Dermatophytes are the major responsible organisms in onychomycosis. Although recent antifungal agents have high success rates in treating this condition, lack of clinical response may occur in 20%. Antifungal drug resistance may be one of the causes of treatment failure. The need for in vitro antifungal drug resistance in daily practice is still under discussion. Objective., We aimed to determine the in vitro susceptibility patterns of dermatophytes causing onychomycosis, against the traditionally available systemic antifungal agents terbinafine, itraconazole and fluconazole. Methods., In total, 100 otherwise healthy patients with suspected onychomycosis were included. Nail clippings were cultured on Sabouraud dexrose agar, mycobiotic agar and dermatophyte test medium. Antifungal susceptibility tests were carried out, mainly following The National Committee for Clinical and Laboratory Standards (M38-P) protocol standard for filamentous fungi. Different concentrations of terbinafine (0.008,8 µg/mL), itraconazole (0.015,16 µg/mL) and fluconazole (0.06,64 µg/mL) were tested. Minimum inhibitory concentration end-point determination was chosen as 100% growth inhibition for terbinafine and 80% for azoles. Results., Of the 100 nail samples, 43% grew dermatophytes. The main causative organism was Trichophyton rubrum (91%) followed by Trichophyton mentagrophytes (9%). Terbinafine had the lowest minimum inhibitory concentration (0.008 µg/mL) followed by itraconazole. Fluconazole showed the greatest variation in minimum inhibitory concentration (0.03,2 µg/mL) and had different susceptibility patterns for the two species. Conclusions., Of the three antifungals tested, terbinafine had the most potent in vitro antifungal activity against dermatophytes. Antifungal susceptibility tests would be useful to screen antifungal-resistant dermatophyte strains. [source] Growth and photorefractive properties of Mg:Ce:Cu:LiNbO3 crystals grown by Czochralski methodCRYSTAL RESEARCH AND TECHNOLOGY, Issue 8 2006Y. X. Fan Abstract In this paper, photorefractive properties of Mg:Ce:Cu:LiNbO3 crystals were studied. The crystals doped with different concentration of Mg ions have been grown by the Czochralski method. Mg concentrations in grown crystals were analyzed by an inductively coupled plasma optical emission spectrometry (ICP-OE/MS). The crystal structures were analyzed by the X-ray powder diffraction (XRD), ultraviolet-visible (UV-Vis) absorption spectra and infrared (IR) transmitatance spectra. The photorefractive properties of crystals were experimentally studied by using two-beam coupling. In this experiment we determined the writing time, maximum diffraction efficiency and the erasure time of crystals samples with He-Ne laser. The results showed that the dynamic range (M/#), sensitivity (S) and diffraction efficiency (,) were dependent on the Mg doping concentration, and the Mg(4.58mol%):Ce:Cu:LiNbO3 crystal was the most proper holographic recording media material among the six crystals studied in the paper. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Inactivation of Escherichia coli K-12 in Apple Juice Using Combination of High-Pressure Homogenization and ChitosanJOURNAL OF FOOD SCIENCE, Issue 1 2009S. Kumar ABSTRACT:, Apple juice and apple cider were inoculated with Escherichia coli K-12 and processed using a high-pressure homogenizer to study bacterial inactivation. Seven levels of pressure ranging from 50 to 350 MPa were used in the high-pressure homogenizer. Two types of chitosan (regular and water soluble) with 2 levels of concentration 0.01% and 0.1% were investigated for synergistic effect with high-pressure homogenization for the bacterial inactivation. E. coli K-12 inactivation was evaluated as a function of homogenizing pressure at different concentration of 2 types of chitosan in apple juice and cider. High-pressure homogenization (HPH) induced significant inactivation in the range of 100 to 200 MPa, while thermal inactivation was the primary factor for the bacterial inactivation above 250 MPa. Significant (P < 0.05) 2-way interactions involving pressure and type of substrate or pressure and chitosan concentration were observed during the study. The homogenization pressure and the incremental quantity of chitosan (both types) acted synergistically with the pressure to give higher inactivation. Significantly (P < 0.05) higher inactivation was observed in apple juice than apple cider at same homogenizing pressure. No effect of type of chitosan was observed on the bacterial inactivation. [source] Equilibrium theory analysis of rectifying PSA for heavy component productionAICHE JOURNAL, Issue 8 2002Armin D. Ebner An isothermal equilibrium theory analysis, based on linear isotherms and a binary feed stream, was carried out to evaluate the feasibility of a rectifying PSA process for producing a pure heavy component at high recovery. Analytic expressions were derived to describe the performance of this process at the periodic state. The performance was also analyzed in terms of the different concentration and velocity profiles exhibited during various cycle steps that included the analysis of complex shock and simple wave interactions. Based on a parametric study, periodic behavior was established for a wide range of process conditions; and a design study with the PCB activated carbon,H2,CH4 system at 25°C further demonstrated the feasibility of a rectifying PSA cycle for producing a 100% CH4 stream from a dilute feed stream (y = 0.01) with a respectable recovery (80%), and reasonable process conditions. It also demonstrated the potential usefulness of an actual rectifying PSA process for bulk gas separation and purification. [source] Ethanol Modulates Corticotropin Releasing Hormone Release From the Rat Hypothalamus: Does Acetaldehyde Play a Role?ALCOHOLISM, Issue 4 2010Carla Cannizzaro Background and Methods:, Ethanol (EtOH) activates hypothalamic,pituitary,adrenal (HPA) axis, resulting in adrenocorticotropin hormone, glucocorticoid release, and in modifications of the response of the axis to other stressors. The initial site of EtOH action within the HPA system seems to be the hypothalamus. Thus, to determine the mechanisms responsible for these effects, we investigated: (i) whether EtOH was able to release corticotrophic releasing hormone (CRH) from incubated hypothalamic explants; (ii) whether acetaldehyde (ACD), its first metabolite formed in the brain by catalase activity, might play a role in EtOH activity. To this aim, rat hypothalamic explants were incubated with: (i) medium containing EtOH at 32.6 × 103 ,M; (ii) different concentration of ACD (1, 3, 10, and 30 ,M); (iii) EtOH plus 3amino-1,2,4-triazole (3AT, 32 × 103 ,M) an inhibitor of cerebral catalase; (iv) ACD plus D-penicillamine (DP, 50.3 × 103 ,M) an ACD-trapping agent. CRH levels were evaluated by a radioimmunoassay. Results:, Incubation with EtOH induced a 7-fold increase in CRH secretion, with respect to basal levels; ACD was able to stimulate CRH release in a dose-dependent manner; the inhibition of cerebral catalase by 3AT blocked EtOH-induced CRH outflow; the inactivation of ACD by DP reverted the ACD-stimulating effect on CRH secretion. Conclusions:, These data show that both EtOH and acetaldehyde are able to increase hypothalamic CRH release from the rat hypothalamus and that acetaldehyde itself appears to be the mediator of EtOH activity. [source] Photoprotection of bacterial-derived melanin against ultraviolet A,induced cell death and its potential application as an active sunscreenJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 7 2008J Geng Abstract Background, The increase in the incidence of non-melanoma skin tumours, photoaging, and immunosuppression demand for more effective sunscreen on ultraviolet A (UVA) irradiation. Objectives, The aim of the study is to evaluate the photoprotective effects of a bacterial-derived melanin against UVA-induced damages in vitro and in vivo. Methods, Human fibroblasts were used to assess the role of the bacterial-derived melanin on cell viability against UVA. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and nuclear morphology were employed to evaluate the photoprotection at the cellular level. Fluorometric assays were performed to detect the formation of reactive oxygen species (ROS) in the cells. Evaluations of the bacterial-derived melanin as a sunscreen were measured by transmission test and persistent pigment darkening on human skin. Results, Bacterial-derived melanin efficiently scavenged ROS in the fibroblasts after UVA irradiation. The cell viability of xeroderma pigmentosum (XP) fibroblast treated with varied doses of melanin increased dramatically in comparison with untreated control and the treated XP fibroblasts became more resistant to UVA-induced apoptosis than normal fibroblasts. Although the relative transmission didn't change too much with different concentration of bacterial-derived melanin, this melanin could keep UVA-irradiated skin from pigment darkening and act as an active sunscreen on skin. Conclusions, The bacterial-derived melanin provided significant protection to fibroblast cell and human skin against the UVA radiation. It has the potential to be developed as an active sunscreen for the patients with photosensitivity skin to sun exposure. [source] Conjugated linoleic acid conversion by dairy bacteria cultured in MRS broth and buffalo milkLETTERS IN APPLIED MICROBIOLOGY, Issue 5 2007C.P. Van Nieuwenhove Abstract Aims:, To evaluate strains of Lactobacilli, Bifidobacteria and Streptococci for their ability to produce conjugated linoleic acid (CLA) from free linoleic acid (LA). Methods and Results:, Eight dairy bacteria tolerant to LA were grown in MRS broth containing LA (200 ,g ml,1) and CLA was assessed. Seven bacteria were able to form CLA after 24 h of incubation, varying percentage conversion between 17% and 36%. Lactobacillus casei, Lactobacillus rhamnosus, Bifidobacterium bifidum and Streptococcus thermophilus showed the highest LA conversion and were inoculated into buffalo milk supplemented with different concentration of LA. The production of CLA at 200 ,g ml,1 of LA was two- or threefold in milk than MRS broth. All evaluated strains were able to produce CLA from high LA levels (1000 ,g ml,1). Conclusions:, The most tolerant strain to LA was Lact. casei. Lacttobacillus rhamnosus produced the maximum level of CLA at high LA concentrations (800 ,g ml,1). The selected bacteria may be considered as adjunct cultures to be included on dairy fermented products manufacture. Low concentration of LA must be added to the medium to enhance CLA formation. Significance and Impact of the Study:, The production of CLA by strains using milks from regional farms as medium offer a possible mechanism to enhance this beneficial compound in dairy products and those the possibility to develop functional foods. [source] Microwave dielectric properties of polybutylene terephtalate (PBT) with carbon black particlesMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 1 2005L. C. Costa Abstract The synthesis of composites based on polymers containing carbon as additives is rather relevant because it has been found that applications in several industries are increasing, particularly due to their unusual mechanical and electrical properties. By choosing the adequate doping concentrations, we can precisely control the electrical properties in the microwave frequencies, in order to tailor the desired behavior. In this study, we present the results of the complex-permittivity measurements, ,* = ,, , í ,,, at 2.7, 5, and 12.8 GHz, on polybutylene terephtalate (PBT), with different concentration of black carbon particles, using the resonant-cavity method. Measuring the shift in the resonant frequency of the cavity, ,f, caused by the insertion of the sample, we can calculate to the real part of the complex permittivity, ,,, while the measure of the change in the inverse of the quality factor of the cavity, ,(1/Q), allow us to calculate the imaginary part, ,,. Maxwell,Wagner,Sillars (MWS) and Looyenga mixture laws are applied to the obtained results. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 61,63, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20901 [source] Study of the activation process of Mg dopant in GaN:Mg layersPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3 2006B. Paszkiewicz Abstract GaN:Mg layers with different concentration of Mg dopant were grown by metalorganic vapour phase epitaxy. The incorporation of Mg was verified by secondary ion mass spectroscopy. In order to dissociate Mg-related complexes and thus electrically activate the acceptor dopant, the as-grown layers were annealed in pure N2 at ,800 °C for 30 minutes. The influence of the post-growth annealing on the layer properties was studied by photoluminescence (PL) and impedance spectroscopy. Impedance spectroscopy measurement showed that the annealed samples reveal higher charge concentrations and lower sheet resistance. Moreover, the relaxation time of hole traps decreased in annealed samples by one order of magnitude compared to as-grown samples. The changes in the electrical properties have been correlated with the changes in the PL spectra. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] The research on the mechanical and tribological properties of carbon fiber and carbon nanotube-filled PEEK compositePOLYMER COMPOSITES, Issue 8 2010Jian Li The main objective of this article is to develop high wear resistance carbon fiber reinforced polyether ether ketone composite with addition of multiwall carbon nanotube (MWCNT). These compounds were well mixed in a Haake batch mixer, and compounded polymers were fabricated into sheets of known thickness by compression molding. Samples were tested for wear resistance with respect to different concentration of fillers. The wear resistance properties of these samples depend on filler aspect ratio. Wear resistance of composite with 20 wt% of CF increases when MWCNT was introduced. The worn surface features have been examined using scanning electron microscope. Photomicrographs of the worn surfaces revealed higher wear resistance with the addition of carbon nanotube. Also, better interfacial adhesion between carbon and vinyl ester in carbon-reinforced vinyl ester composite was observed. POLYM. COMPOS., 31:1315,1320, 2010. © 2009 Society of Plastics Engineers [source] Pyroelectric investigations of a hydrogen bonded ferroelectric liquid crystal gel by LIMMPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 1 2005Jianjun Li Abstract The laser intensity modulation method (LIMM) is employed to determine spatially resolved polarization distributions in sandwich cells containing a hydrogen-bonded ferroelectric liquid crystal (FLC) gel. At no external electric fields, contributions to the distributions at the surface of the FLC layer are dominating in all the samples with different concentration of gel former. These are attributed to non-vanishing polarization due to surface interaction. In this case, the effect of hydrogen-bonded network on the polarization distribution is not visible. In external electric fields, additional contribution to the resulting distribution caused by the induced polarization due to unwinding the FLC helix has been observed. Furthermore, the influence of hydrogen-bonded network on the polarization distribution is also detected when the gel former content is increased up to 5.0,wt%. Therein the shape of the measured pyrospectra is completely different to other FLC gel samples with lower gel former concentration, where their maximum distributions still locate at the surface of FLC layer which is comparable to the initial field-free state. These result indicate that the helical structure and orientation director of FLC are able to be stabilized effectively by the gel network even under strong external electric field. Copyright © 2004 John Wiley & Sons, Ltd. [source] Caffeine and theophylline block insulin-stimulated glucose uptake and PKB phosphorylation in rat skeletal musclesACTA PHYSIOLOGICA, Issue 1 2010A. J. Kolnes Abstract Aim:, Caffeine and theophylline inhibit phosphatidylinositol 3-kinase (PI3-kinase) activity and insulin-stimulated protein kinase B (PKB) phosphorylation. Insulin-stimulated glucose uptake involves PI3-kinase/PKB, and the aim of the present study was to test the hypothesis that caffeine and theophylline inhibit insulin-stimulated glucose uptake in skeletal muscles. Methods:, Rat epitrochlearis muscles and soleus strips were incubated with insulin and different concentrations of caffeine and theophylline for measurement of glucose uptake, force development and PKB phosphorylation. The effect of caffeine was also investigated in muscles stimulated electrically. Results:, Caffeine and theophylline completely blocked insulin-stimulated glucose uptake in both soleus and epitrochlearis muscles at 10 mm. Furthermore, insulin-stimulated PKB Ser473 and Thr308 and GSK-3, Ser9 phosphorylation were blocked by caffeine and theophylline. Caffeine reduced and theophylline blocked insulin-stimulated glycogen synthase activation. Caffeine stimulates Ca2+ release and force development increased rapidly to 10,20% of maximal tetanic contraction. Dantrolene (25 ,m), a well-known inhibitor of Ca2+ -release, prevented caffeine-induced force development, but caffeine inhibited insulin-stimulated glucose uptake in the presence of dantrolene. Contraction, like insulin, stimulates glucose uptake via translocation of glucose transporter-4 (GLUT4). Caffeine and theophylline reduced contraction-stimulated glucose uptake by about 50%, whereas contraction-stimulated glycogen breakdown was normal. Conclusion:, Caffeine and theophylline block insulin-stimulated glucose uptake independently of Ca2+ release, and the likely mechanism is via blockade of insulin-stimulated PI3-kinase/PKB activation. Caffeine and theophylline also reduced contraction-stimulated glucose uptake, which occurs independently of PI3-kinase/PKB, and we hypothesize that caffeine and theophylline also inhibit glucose uptake in skeletal muscles via an additional and hitherto unknown molecule involved in GLUT4 translocation. [source] Placebo-controlled evaluation of the irritant potential of tacalcitol (1,, 24-dihydroxyvitamin D3) in healthy volunteersCONTACT DERMATITIS, Issue 5 2000K. Schlotmann In the treatment of psoriasis with topical vitamin D3 analogues, lesional and perilesional irritation is the main side-effect. The aim of this study was to investigate whether local side-effects generated by tacalcitol, a vitamin D3 analogue, show concentration dependence. 3 different concentrations of tacalcitol (0.4; 4; 40 ,g/g ointment) and the vehicle were applied on normal skin of the back of 25 healthy volunteers under occlusive conditions for 5 days. Assessment of erythema, infiltration and scaling as well as measurement of transepidermal water loss (TEWL) was performed on days 1 to 5. On day 5, additional skin barrier tests (DMSO test, alkali resistance test) were performed. Erythema and slight infiltration, but no scaling, were observed in a number of subjects without significant differences. TEWL also did not show significant differences for the test formulations, though there was a tendency towards lower values in the untreated areas. In the skin barrier tests, a tendency towards higher alkali resistance in the test areas treated with 40 ,g tacalcitol/g ointment was detected. Thus, under occlusive conditions, the irritant potential of tacalcitol is very low. There is no convincing evidence of concentration dependence in irritation generated by tacalcitol when applied under occlusive conditions. [source] Development and validation of a smoothing-splines-based correction method for improving the analysis of CEST-MR imagesCONTRAST MEDIA & MOLECULAR IMAGING, Issue 4 2008J. Stancanello Abstract Chemical exchange saturation transfer (CEST) imaging is an emerging MRI technique relying on the use of endogenous or exogenous molecules containing exchangeable proton pools. The heterogeneity of the water resonance frequency offset plays a key role in the occurrence of artifacts in CEST-MR images. To limit this drawback, a new smoothing-splines-based method for fitting and correcting Z -spectra in order to compensate for low signal-to-noise ratio (SNR) without any a priori model was developed. Global and local voxel-by-voxel Z -spectra were interpolated by smoothing splines with smoothing terms aimed at suppressing noise. Thus, a map of the water frequency offset (,zero' map) was used to correctly calculate the saturation transfer (ST) for each voxel. Simulations were performed to compare the method to polynomials and zero-only-corrected splines on the basis of SNR improvement. In vitro acquisitions of capillaries containing solutions of LIPOCEST agents at different concentrations were performed to experimentally validate the results from simulations. Additionally, ex vivo investigations of bovine muscle mass injected with LIPOCEST agents were performed as a function of increasing pulse power. The results from simulations and experiments highlighted the importance of a proper ,zero' correction (15% decrease of fictitious CEST signal in phantoms and ex vivo preparations) and proved the method to be more accurate compared with the previously published ones, often providing a SNR higher than 5 in different simulated and experimentally noisy conditions. In conclusion, the proposed method offers an accurate tool in CEST investigation. Copyright © 2008 John Wiley & Sons, Ltd. [source] Habit modification and improvement in properties of potassium hydrogen phthalate (KAP) crystals doped with metal ionsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 3 2006S. K. Geetha Abstract Potassium hydrogen phthalate (KAP) single crystals were grown by slow evaporation and slow cooling techniques. The growth procedure like temperature cooling rate, evaporation rate, solution pH, concentration of the solute, supersaturation ratio etc., has been varied to have optically transparent crystals. Efforts were made to dope the KAP crystals with rubidium, sodium and lithium ions. The dopant concentration has been varied from 0.01 to 10 mole percent. Good quality single crystals were grown with different concentrations of dopants in the mother phase. Depending on the concentration of the dopants and the solution pH value, there is modification of habit. Rubidium ions very much improve the growth on the prismatic faces. The transparency of the crystals is improved with rubidium and sodium doping. The role of the dopants on the non-linear optical performance of KAP indicates better efficiency for doped crystals. The grown crystals were characterized with XRD, FT-IR, chemical etching, Vickers microhardness and SHG measurements. The influence of the dopants on the optical, chemical, structural, mechanical and other properties of the KAP crystals was analysed. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim [source] Growth and characterization of undoped, Sr2+ -, and Mn2+ -doped ammonium tetrachlorozincateCRYSTAL RESEARCH AND TECHNOLOGY, Issue 3 2005M. A. Gaffar Abstract Crystals of ammonium tetrachlorozincate (AZC) undoped and doped with Sr2+ or Mn2+ in different concentrations were grown by the slow evaporation method from an aqueous solution. The crystal morphology changed considerably by doping. The dopant concentration in the crystals was measured by the atomic absorption technique. Slight changes in the unit cell parameters of AZC after doping with Sr2+ - or Mn2+ have been detected. Optical absorption measurements indicated strong influence of Sr2+ and Mn2+ doping. The optical energy gap at room temperature decreased continuously with increasing Sr2+ and Mn2+ concentration but with two different rates. The dc conductivity was also measured as a function of temperature for the undoped and two samples doped with 0.144 Sr2+ and 0.191 Mn2+ and the results were compared. Positions possibly occupied by Sr2+ and Mn2+ cations in AZC lattice have been identified. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Compaction of cell shape occurs before decrease of elasticity in CHO-K1 cells treated with actin cytoskeleton disrupting drug cytochalasin DCYTOSKELETON, Issue 4 2009Christian Schulze Abstract The actin filaments of the cytoskeleton form a highly dynamic polymer scaffold which is actively involved in many essential mechanisms such as cell migration, transport, mitosis, and mechanosensitivity. We treated CHO-K1 cells with different concentrations of the actin cytoskeleton disrupting drug cytochalasin D. Then investigating the cells' elastic behaviour by scanning force microscopy-based rheology we confirmed for high cytochalasin D concentrations (,1.5 ,M) a significant decrease of mechanical stability. At lower concentrations we measured no significant softening, but flattening and a horizontal contraction was observable even at low concentrations (,0.3 ,M) of cytochalasin D. The observed changes in cell shape resulted in a lower cell volume, showing that there is compensation by volume for small decreases in cytoskeletal strength resulting from reduced numbers or lengths of actin filaments. These results suggest that the characteristic functions defining a cell's mechanical stability such as mechanosensitivity can be maintained via small changes in cell volume in order to counter fluctuations in cytoskeletal composition. Cell Motil. Cytoskeleton 2009. © 2009 Wiley-Liss, Inc. [source] Enhancement of In Vitro Hair Shaft Elongation in Follicles Stored in Buffers That Prevent Follicle Cell ApoptosisDERMATOLOGIC SURGERY, Issue 1 2004Walter Krugluger MD Background. Viability and survival of stored micrografts during hair follicle transplantation are important limitations of micrograft transplantation procedures. In this study, we investigated the effect of different storage solutions and inhibitors of apoptotic cell death (ACD) on hair follicle cell viability by measuring in vitro hair shaft elongation (HSE) for 5 days. Methods. Micrografts from informed patients undergoing routine micrograft transplantation were stored for 5 hours at room temperature in phosphate-buffered salt solution (PBS) or HEPES-buffered Dulbecco's modified Eagle's medium (DMEM), containing different concentrations of the ACD-inhibitors aminoguanidine (AMG), hormones (insulin, hydrocortisone), 14,15-epoxy-eicosatrienoic acid (14,15-EET), or combinations of these. Results. In vitro, HSE was significantly increased in micrografts stored in DMEM compared with PBS (2.3%±0.6% vs. 28.4%±3.9%, P<0.0001). DMEM supplemented with AMG (10 ,g/mL) or 14,15-EET (1 ng/mL) further increased in vitro HSE (33.9%±7.1%, p=0.01, and 32.8%±6.1%, P=0.02, respectively). Evaluation of ACD in stored micrografts, performed by determination of cytoplasmic histone-associated DNA fragments, confirmed the results found by HSE. ACD was detectable after a 36-hour culture in serum-containing medium and was higher in micrografts stored in PBS compared with micrografts stored in DMEM (A405nm/A492nm: 1.63±0.21 vs. 1.42±0.07, respectively; P<0.01). The addition of AMG further decreased serum-induced ACD in the micrografts (DMEM 1.42±0.07 vs. DMEM/AMG 0.90±0.11, P<0.0001). Conclusion. Our study demonstrated an important role of ACD in micrograft transplantation surgery. Preconditioning of micrografts with storage buffers containing inhibitors of ACD could prevent serum-induced ACD after transplantation and might increase the viability of micrografts and the clinical outcome in micrograft transplantation. [source] Pre-activation of retinoid signaling facilitates neuronal differentiation of mesenchymal stem cellsDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 5 2010Yang Bi Mesenchymal stem cells (MSCs) can differentiate into neurons in an appropriate cellular environment. Retinoid signaling pathway is required in neural development. However, the effect and mechanism through retinoid signaling regulates neuronal differentiation of MSCs are still poorly understood. Here, we report that all-trans-retinoic acid (ATRA) pre-induction improved neuronal differentiation of rat MSCs. We found that, when MSCs were exposed to different concentrations of ATRA (0.01,100 ,mol/L) for 24 h and then cultured with modified neuronal induction medium (MNM), 1 ,mol/L ATRA pre-induction significantly improved neuronal differentiation efficiency and neural-cell survival. Compared with MNM alone induced neural-like cells, ATRA/MNM induced cells expressed higher levels of Nestin, neuron specific enolase (NSE), microtubule-associated protein-2 (MAP-2), but lower levels of CD68, glial fibrillary acidic protein (GFAP), and glial cell line-derived neurotrophic factor(GDNF), also exhibited higher resting membrane potential and intracellular calcium concentration, supporting that ATRA pre-induction promotes maturation and function of derived neurons but not neuroglia cells from MSCs. Endogenous retinoid X receptors (RXR) RXR, and RXR, (and to a lesser extent, RXR,) were weakly expressed in MSCs. But the expression of RAR, and RAR, was readily detectable, whereas RAR, was undetectable. However, at 24 h after ATRA treatment, the expression of RAR,, not RAR, or RAR,, increased significantly. We further found the subnuclear redistribution of RAR, in differentiated neurons, suggesting that RAR, may function as a major mediator of retinoid signaling during neuronal differentiation from MSCs. ATRA treatment upregulated the expression of Vimentin and Stra13, while it downregulated the expression of Brachyury in MSCs. Thus, our results demonstrate that pre-activation of retinoid signaling by ATRA facilitates neuronal differentiation of MSCs. [source] Mechanisms of Hedgehog gradient formation and interpretationDEVELOPMENTAL NEUROBIOLOGY, Issue 4 2005Carlos Torroja Abstract Morphogens are molecules that spread from localized sites of production, specifying distinct cell outcomes at different concentrations. Members of the Hedgehog (Hh) family of signaling molecules act as morphogens in different developmental systems. If we are to understand how Hh elicits multiple responses in a temporally and spatially specific manner, the molecular mechanism of Hh gradient formation needs to be established. Moreover, understanding the mechanisms of Hh signaling is a central issue in biology, not only because of the role of Hh in morphogenesis, but also because of its involvement in a wide range of human diseases. Here, we review the mechanisms affecting the dynamics of Hh gradient formation, mostly in the context of Drosophila wing development, although parallel findings in vertebrate systems are also discussed. © 2005 Wiley Periodicals, Inc. J Neurobiol 64: 334,356, 2005 [source] | |||||||||||||||||||||||||||||||||||||||||||