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Selected AbstractsEffects of experimental small-scale grassland fragmentation on spatial distribution, density, and persistence of ant nestsECOLOGICAL ENTOMOLOGY, Issue 6 2003Brigitte Braschler Abstract., 1.,Grassland fragmentation is expected to influence the abundance of different invertebrate species to a different extent. Fragmentation-related effects are of particular importance in species that interact with many other species. 2.,The density and spatial distribution of nests of 15 ant species in experimentally fragmented calcareous grasslands at three sites in the Northern Swiss Jura mountains were examined. Fragments of different size (0.25 m2, 2.25 m2, and 20.25 m2) were isolated by a 5-m wide strip of frequently mown vegetation. Control plots of corresponding size were situated in adjacent undisturbed grassland. 3.,Three years after initiation of the experiment, ant nest density did not differ between fragments and control plots. Six years after initiation of the experiment, however, ant nest density and forager abundance were higher in large fragments than in large control plots. Ant nests tended to occur more frequently along the edge of fragments than in the core area. Persistence time of nests of the most abundant species, Lasius paralienus, tended to be shorter in fragments than in control plots. Furthermore, persistence time was longer in nests situated close to the fragment edge than in nests in the core area. 4.,Effects on nest density, edge effects on the spatial distribution of nests, and the relationships between nest density and environmental factors were more pronounced when only nests of L. paralienus were considered. The implications of these findings for plant and other invertebrate species are discussed. [source] Cascading effects of variation in plant vigour on the relative performance of insect herbivores and their parasitoidsECOLOGICAL ENTOMOLOGY, Issue 1 2002Tiit Teder Abstract 1. Consequences of variation in food plant quality were estimated for a system consisting of two monophagous noctuid herbivores and three ichneumonid parasitoids. 2. In a natural population, pupal weights of the herbivores in this system, Nonagria typhae and Archanara sparganii, were found to be highly variable. Pupal weights increased strongly and consistently with the increase in the vigour of the host plant, Typha latifolia, providing support for the plant vigour hypothesis. Correspondingly, as the moths do not feed as adults, a strong, positive correlation between host vigour and fecundity of the herbivores would be expected. 3. There were strong and positive relationships between adult body sizes of the parasitoids and the sizes of their lepidopteran hosts. Moreover, a direct, positive link between plant quality and parasitoid size was documented. 4. For all three parasitoids, cascading effects of plant quality on body size were weaker than for the herbivores. Differences in the importance of adult feeding and oviposition behaviour suggest that dependence of fitness on body size is also weaker in the parasitoids than in the moths. It is therefore concluded that the numerical response of the herbivore population to a change in plant quality should exceed the corresponding response in the parasitoids. 5. The results of this work imply that variation in plant variables may affect performance of different trophic levels to a different extent. It is suggested that the importance of adult feeding for the reproductive success (capital vs. income breeding strategies) in both herbivores and parasitoids is an essential aspect to consider when predicting responses of such a system to changes in plant quality. [source] Experimental and Clinical Evidence for Loss of Effect (Tolerance) during Prolonged Treatment with Antiepileptic DrugsEPILEPSIA, Issue 8 2006Wolfgang Löscher Summary:, Development of tolerance (i.e., the reduction in response to a drug after repeated administration) is an adaptive response of the body to prolonged exposure to the drug, and tolerance to antiepileptic drugs (AEDs) is no exception. Tolerance develops to some drug effects much more rapidly than to others. The extent of tolerance depends on the drug and individual (genetic?) factors. Tolerance may lead to attenuation of side effects but also to loss of efficacy of AEDs and is reversible after discontinuation of drug treatment. Different experimental approaches are used to study tolerance in laboratory animals. Development of tolerance depends on the experimental model, drug, drug dosage, and duration of treatment, so that a battery of experimental protocols is needed to evaluate fully whether tolerance to effect occurs. Two major types of tolerance are known. Pharmacokinetic (metabolic) tolerance, due to induction of AED-metabolizing enzymes has been shown for most first-generation AEDs, and is easy to overcome by increasing dosage. Pharmacodynamic (functional) tolerance is due to "adaptation" of AED targets (e.g., by loss of receptor sensitivity) and has been shown experimentally for all AEDs that lose activity during prolonged treatment. Functional tolerance may lead to complete loss of AED activity and cross-tolerance to other AEDs. Convincing experimental evidence indicates that almost all first-, second-, and third-generation AEDs lose their antiepileptic activity during prolonged treatment, although to a different extent. Because of diverse confounding factors, detecting tolerance in patients with epilepsy is more difficult but can be done with careful assessment of decline during long-term individual patient response. After excluding confounding factors, tolerance to antiepileptic effect for most modern and old AEDs can be shown in small subgroups of responders by assessing individual or group response. Development of tolerance to the antiepileptic activity of an AED may be an important reason for failure of drug treatment. Knowledge of tolerance to AED effects as a mechanism of drug resistance in previous responders is important for patients, physicians, and scientists. [source] Induction of apoptosis in monocytes by Mycobacterium leprae in vitro: a possible role for tumour necrosis factor-,IMMUNOLOGY, Issue 1 2003M. O. Hernandez Summary A diverse range of infectious organisms, including mycobacteria, have been reported to induce cell death in vivo and in vitro. Although morphological features of apoptosis have been identified in leprosy lesions, it has not yet been determined whether Mycobacterium leprae modulates programmed cell death. For that purpose, peripheral blood mononuclear cells obtained from leprosy patients were stimulated with different concentrations of this pathogen. Following analysis by flow cytometry on 7AAD/CD14+ cells, it was observed that M. leprae induced apoptosis of monocyte-derived macrophages in a dose-dependent manner in both leprosy patients and healthy individuals, but still with lower efficiency as compared to M. tuberculosis. Expression of tumour necrosis factor-, (TNF-,), Bax-,, Bak mRNA and TNF-, protein was also detected in these cultures; in addition, an enhancement in the rate of apoptotic cells (and of TNF-, release) was noted when interferon-, was added to the wells. On the other hand, incubation of the cells with pentoxifylline impaired mycobacterium-induced cell death, the secretion of TNF-,, and gene expression in vitro. In addition, diminished bacterial entry decreased both TNF-, levels and the death of CD14+ cells, albeit to a different extent. When investigating leprosy reactions, an enhanced rate of spontaneous apoptosis was detected as compared to the unreactive lepromatous patients. The results demonstrated that M. leprae can lead to apoptosis of macrophages through a mechanism that could be at least partially related to the expression of pro-apoptotic members of the Bcl-2 protein family and of TNF-,. Moreover, while phagocytosis may be necessary, it seems not to be crucial to the induction of cell death by the mycobacteria. [source] Effect of the side chain size of 1-alkyl-pyrroles on antioxidant activity and ,Laba' garlic greeningINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 10 2008Dan Wang Summary Previous studies showed that 1-alkyl-pyrroles not only occur in fresh food products postulated as a natural antioxidant but also might be involved in garlic greening. In the present study, a series of 1-alkyl-pyrroles with different side chain size were synthesised to study the relationship of structure and antioxidative activity and their effects on ,Laba' garlic greening. The antioxidative activity of these compounds was evaluated by the method of scavenging ABTS, and DPPH,. Results showed that increasing the size of R groups on the side chain, the antioxidative activity decreased gradually against the two radicals. The 1-alkyl-pyrroles generally exhibited stronger scavenging activities against ABTS, than DPPH,. In contrast, their corresponding amino acids except for tyrosine showed almost no antioxidative activities while pyrrole exhibited much weaker activity as compared with the 1-alkyl-pyrroles, suggesting that the 1-alkyl-pyrroles donate H-atom from pyrrole moiety rather than side chain to quench the two radicals. On the other hand, all 1-alkyl-pyrroles can turn newly harvested garlic green but to a different extent. All these results suggested that these pyrrole derivatives occurring in foodstuff played an important role in either protecting foodstuff from oxidation or acting on pigment precursors during ,Laba' garlic greening. [source] Quality Attributes and Microbial Storage Stability of Caviar from Cultivated White Sturgeon (Acipenser transmontanus)JOURNAL OF FOOD SCIENCE, Issue 1 2010Joong-Han Shin ABSTRACT:, Caviar was prepared from white sturgeon (Acipenser transmontanus) roe by adjusting the water phase salt (WPS) to 4.0% to 6.3% by adding food grade NaCl. Fish were obtained from 2 different farms from the Inland Northwest (N,= 5). Salt was absorbed at a different rate and to a different extent by roe from different fish. The lipid content in the fish roe varied from 10.2% to 14.4% (w/w), with palmitic acid and oleic acid being the most abundant saturated and monounsaturated fatty acids present, respectively. The caviar contained high levels of polyunsaturated fatty acids (PUFA) (35% to 37%) with docosahexanoic acid being the most abundant ,-3 long chain fatty acid. There were no significant differences in microbial storage stability for caviars from different fish stored at 3 °C. However, for caviar stored at 7 °C, there was less growth of,Listeria monocytogenes,(using a cocktail of ATCC 19114, 7644, 19113 strains) in 2 samples (2B46 and 0F05) until day 20. In 2 other samples (453F and 2519), which had lower initial microbial loads, less overall microbial growth was observed, indicating that culture and harvest practices result in compositional differences between fish, which may impact both product composition and storage stability. [source] The formation of foliated (garnet-bearing) granites in the Tongbai-Dabie orogenic belt: partial melting of subducted continental crust during exhumationJOURNAL OF METAMORPHIC GEOLOGY, Issue 9 2009L. ZHANG Abstract Foliated (garnet-bearing) (FGB) granites are associated closely with and are usually the major wall rocks of the high-pressure (HP) and ultrahigh-pressure (UHP) metamorphic rocks in the Tongbai-Dabie region, the mid segment of the Qinling-Dabie-Sulu orogenic belt in central China. These granites appear either as small plutons or as veins, which commonly intrude into or surround the HP and UHP metamorphic eclogites or gneisses. The veins of FGB granites usually penetrate into the retrograded eclogites or gneisses along the foliations. Condensation rims can occasionally be found along the margins of granite veins. These granites are rich in Si and alkali with high Ga/Al ratios, and depleted in Ca, Mg, Al, Ti, Sc, V, Ni, Co, Cr and Sr, which are similar to A-type granites. In a chondrite normalized diagram, the samples are light rare earth elements enriched with different extent of negative Eu anomaly. Moreover, Rb, Nb, Ta, Sr, P and Ti show different degrees of negative anomalies, whereas Ba, K, La, Zr and Hf show positive anomalies in the primitive mantle normalized diagram. Negative anomalies of Eu and Sr indicate strong influence of plagioclase. In conventional discrimination diagrams, these FGB granites belong to the A-type granite, with geochemical characteristics affinitive to post-collisional granites. The ,Nd (230 Ma) values (,15.80 to ,2.52) and TDM values (1.02,2.07 Ga) suggest that magma for the FGB granites were derived from a heterogeneous crustal source. Therefore, the FGB granites may provide clues for deciphering the formation of post-collisional granites. It is proposed that the magma of the FGB granites both in the HP and UHP units was formed in an extensional tectonic setting slightly post-dating the HP and UHP metamorphism, most likely as a result of decompressional partial melting of UHP retrograded eclogites during exhumation. [source] A Contingency Perspective of Communication, Conflict Resolution and Buyer Search Effort in Buyer-Supplier RelationshipsJOURNAL OF SUPPLY CHAIN MANAGEMENT, Issue 1 2004Cindy Claycomb SUMMARY This study investigates the moderating effects of buying context on the relationship between communication elements and the effort buyers exert while searching for new suppliers throughout a buyer-supplier relationship development process. A mail survey of members of the Institute for Supply ManagementÔ was conducted and the data were analyzed using moderated regression. The results suggest that company size, buyer experience, relationship duration and relationship importance affect the association between a buyer's search effort and the communication elements. Interestingly, the buying context affects the relationship between search effort and the communication elements in different ways and to a different extent in each stage of the relationship development process. [source] Effects of green tea extract on the quality of bread made from unfrozen and frozen dough processesJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 6 2006Rong Wang Abstract Two different green tea extracts (GTE-A and -B) as a rich source of tea catechins were incorporated into a no-time bread-making process, where bread made from the unfrozen and frozen dough processes was compared by specific volume and texture profile. GTE-A and -B both exhibited significant effects on bread volume and firmness, but to a different extent. GTE-A with higher content of tea catechins (73%) at a level of 1.5 g kg,1 flour was found to lead to a significant reduction in bread volume in unfrozen dough process and an increment in firmness during storage for 4 days at ambient temperature (22 °C). GTE-B, with a lower content of catechins (60%), had relatively mild effects on the bread quality. Significantly negative effects were evident starting at a higher level of 5.0 g kg,1 flour in unfrozen dough process. Frozen storage showed more predominant deteriorating effects than the GTEs over a period of 9 weeks frozen storage at ,20 °C. Copyright © 2006 Society of Chemical Industry [source] Major differences in bleeding symptoms between factor VII deficiency and hemophilia BJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 5 2009F. 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] PE-CVD of Acid/Base Coatings from Acrylic Acid and Allylamine VapoursPLASMA PROCESSES AND POLYMERS, Issue S1 2007Eloisa Sardella Abstract Different plasma processes were investigated to obtain coatings characterized by N and O functional groups at their surface. From the literature, big efforts are evident devoted to designing new surfaces with chemical composition and chemical,physical properties tightly controlled. This paper demonstrates how it is possible to obtain coatings with acid and basic properties at different extent, by simply adjusting the acrylic acid/allylamine chemical composition of the gas feed in a plasma deposition process. The deposited films exhibit tuneable acid,base properties, very attractive to manufacture sensors, and biomaterials, and for applications in tissue engineering field. [source] Loss of TIP1;1 aquaporin in Arabidopsis leads to cell and plant deathTHE PLANT JOURNAL, Issue 6 2004Shisong Ma Summary Arabidopsis TIP1;1 (,TIP) is a member of the tonoplast family of aquaporins (AQP). Using RNA interference (RNAi) we reduced TIP1;1 to different extent in various lines. When most severely affected, miniature plants died, a phenotype partially complemented by the TIP1;1 homolog McMIP-F. Less severely affected lines produced small plants, early senescence, and showed lesion formation. The relative water content in TIP1;1 RNAi plants was not significantly affected. Global expression profiling suggested a disturbance in carbon metabolism in RNAi lines with upregulated transcripts for functions in carbon acquisition and respiration, vesicle transport, signaling and transcription, and radical oxygen stress. Metabolite profiles showed low glucose, fructose, inositol, and threonic, succinic, fumaric, and malic acids, but sucrose levels were similar to WT. Increased amounts were found for raffinose and several unknown compounds. TIP1;1 RNAi plants also contained high starch and apoplastic carbohydrate increased. A GFP-TIP1;1 fusion protein indicated tonoplast location in spongy mesophyll cells, and high signal intensity in palisade mesophyll associated with vesicles near plastids. Signals in vascular tissues were strongest not only in vesicle-like structures but also outlined large vacuoles. Compromised routing of carbohydrate and lack of sucrose provision for cell-autonomous functions seems to characterize this RNAi phenotype. We suggest a function for TIP1;1 in vesicle-based metabolite routing through or between pre-vacuolar compartments and the central vacuole. Phenotype and expression characteristics support a view of TIP1;1 functioning as a marker for vesicles that are targeted to the central vacuole. [source] DBD regeneration of GAC loaded with acid orange 7ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2009Guang-Zhou Qu Abstract Activated carbon (AC) has been widely used as adsorbent in various industrial applications, such as purification of water in sewage facilities and filtration of air in toxicity-treating factories. However, after exhaustion, AC should be regenerated and reused because of the limited resources for AC production and additional secondary pollution of spent-carbon dumped into water or soil. In this study, a process for regenerating AC based on high active species (O3, ·OH, HO2, O2, ·RO, etc.) generated by dielectric barrier discharge (DBD) oxidation was proposed. The regeneration of granular-activated carbon (GAC) exhausted with azo dye acid orange 7 was investigated to assay this method. The influences of the parameters, such as treatment time, electric field and gas kind, on the readsorption rate were studied systematically. The results of structural properties of GAC analyses showed that the surface area, the micropore area, external surface area, micropore volume and total volume of GAC after three cycles DBD treatment decreased to different extent. The adsorption isotherms indicated that the regeneration efficiency was about 81% after three times DBD plasma regeneration cycles, which confirmed the reuse feasibility of the regenerated GAC. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Effects of macromolecular impurities and of crystallization method on the quality of eubacterial aspartyl-tRNA synthetase crystalsACTA CRYSTALLOGRAPHICA SECTION D, Issue 6 2005A. 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] Inhibition of defective adenylosuccinate lyase by HNE: A neurological disease that may be affected by oxidative stressBIOFACTORS, Issue 1-4 2005C. Crifò Abstract Adenylosuccinate lyase is an enzyme of fumarase superfamily that participates in the purine biosynthetic pathway, catalysing the nonhydrolytic cleavage of succinyl groups from SAICA ribotide and adenylosuccinate. Enzyme defects are associated with a human inherited disease, which arises from single point mutations to the gene and results in mild to severe psychomotor retardation, epilepsy, muscle wasting, and autistic features. Adenylosuccinate lyase activity is lost to a different extent in the patients. Diminished levels of enzyme have been attributed to loss of catalytic activity, protein instability, or environmental factors. P100A/D422Y mutation represents a feasible model for studying the effect of cell milieu on the activity of the impaired enzyme. The defective enzyme is inhibited by micromolar concentrations of trans-4-hydroxy-2-nonenal (HNE), a major product of membrane peroxidation that has been found to accumulate in brain tissues of patients with neurodegenerative disorders. It is suggested that inactivation of defective adenylosuccinate lyase by HNE and other membrane peroxidation products may account, at least in part, for the impairment of neurological functions and recurrent worsening of the symptoms. [source] Effect of the applied organic load rate on biodegradable polymer production by mixed microbial cultures in a sequencing batch reactorBIOTECHNOLOGY & BIOENGINEERING, Issue 1 2006Davide Dionisi Abstract This article studies the operation of a new process for the production of biopolymers (polyhydroxyalkanoates, PHAs) at different applied organic load rates (OLRs). The process is based on the aerobic enrichment of activated sludge to obtain mixed cultures able to store PHAs at high rates and yields. A mixture of acetic, lactic, and propionic acids at different concentrations (in the range 8.5,31.25 gCOD/L) was fed every 2 h in a sequencing batch reactor (SBR). The resulting applied OLR was in the range 8.5,31.25 gCOD/L/day. Even though, as expected, the increase in the OLR caused an increase in biomass concentration (up to about 8.7 g COD/L), it also caused a relevant decrease of maximal polymer production rate. This decrease in polymer production rate was related to the different extent of "feast and famine" conditions, as function of the applied OLR and of the start-up conditions. As a consequence the best performance of the process was obtained at an intermediate OLR (20 gCOD/L/day) where both biomass productivity and PHA storage were high enough. However, at this high OLR the process was unstable and sudden decrease of performance was also observed. The sludge characterized by the highest PHA storage response was investigated by 16S rDNA clone library. The clone library contained sequences mostly from PHA producers (e.g., Alcaligenes and Comamonas genera); however many genera and among them, one of the dominant (Thauera), were never described before in relation to PHA storage response. © 2005 Wiley Periodicals, Inc. [source] Renal damage in vesico-ureteric refluxBJU INTERNATIONAL, Issue 4 2004P. Caione OBJECTIVE To detect the different extent of renal parenchymal involvement in primary vesico-ureteric reflux (VUR), and to evaluate the relationship between VUR grade, patient age and different patterns of parenchymal damage. PATIENTS AND METHODS This blinded retrospective study included 197 consecutive children (mean age 4.26 years, range 1 month to 13 years) with primary VUR detected by voiding cysto-urethrography (VCUG), 99mTc-dimercaptosuccinic acid (DMSA; 120 MBq/1.73 m2) renal scintigraphy, with scanning for 3 h after intravenous injection. An abnormal DMSA scan was classified into three subtypes: cortical defects as a single scar (SS), multiple cortical scarring (MS) and diffuse reduced uptake with small renal size. Renal absolute uptake (AU), and split-kidney relative uptake were evaluated in refluxing and nonrefluxing renal units, and correlated with parenchymal damage and patient age. Student's t -test and the chi-square test were used for the statistical analysis. RESULTS In all, 282 refluxing and 112 nonrefluxing units were assessed. Renal damage was detected in 188 of 282 units with VUR (67%) and in 18 of 112 (16%) contralateral nonrefluxing kidneys. The mean AU was 18.7% in kidneys with VUR and 29% in nonrefluxing units (P < 0.001). The mean (sd) AU decreased from lower to higher grades of VUR, i.e. grade 0 VUR (group A), 28.97 (9.71); grade 1,3 (group B), 21.28 (8.33); grade 4,5 (group C), 14.78 (8.02). The differences were statistically significant (A vs B, B vs C, both P < 0.001). Renal damage was differently distributed in the three groups: 69 of 109 kidneys (63%) in group C (MS prevalent), 39 of 173 (22.5%) in group B (SS prevalent) and 17 of 112 (15.2%) in group A. There was no significant difference in the distribution of renal damage subtypes in patients aged <,or >,2 years (SS 19.6% vs 17.9%, MS 29.6% vs 30.1%, small size 48.2% vs 46.3%). The VUR was severe (group C) in 65% of patients aged <,2 years and in 46% aged >,2 years (chi-square, P= 0.016). CONCLUSIONS VUR is commonly associated with renal damage. Age (< or >,2 years) did not significantly influence the kidney lesion subtype. Reduced parenchymal function (AU) progressively decreased with the severity of VUR. Focal MS, reduced size and relative uptake were significantly more common in severe VUR, leading to multifocal lesions and hypo-dysplasia. Renal scarring was present in up to 15% of contralateral nonrefluxing kidneys. Severe VUR behaved differently from lesser VUR in the renal scan parenchymal uptake. [source] Insight Into the Kinetic of Amyloid , (1,42) Peptide Self-Aggregation: Elucidation of Inhibitors' Mechanism of ActionCHEMBIOCHEM, Issue 17 2007Manuela Bartolini Dr. Abstract The initial transition of amyloid , (1,42) (A,42) soluble monomers/small oligomers from unordered/,-helix to a ,-sheet-rich conformation represents a suitable target to design new potent inhibitors and to obtain effective therapeutics for Alzheimer's disease. Under optimized conditions, this reliable and reproducible CD kinetic study showed a three-step sigmoid profile that was characterized by a lag phase (prevailing unordered/,-helix conformation), an exponential growth phase (increasing ,-sheet secondary structure) and a plateau phase (prevailing ,-sheet secondary structure). This kinetic analysis brought insight into the inhibitors' mechanism of action. In fact, an increase in the duration of the lag phase can be related to the formation of an inhibitor,A, complex, in which the non-amyloidogenic conformation is stabilized. When the exponential rate is affected exclusively, such as in the case of Congo red and tetracycline, then the inhibitor affinity might be higher for the pleated ,-sheet structure. Finally, by adding the inhibitor at the end of the exponential phase, the soluble protofibrils can be disrupted and the A, amyloidogenic structure can revert into monomers/small oligomers. Congo red and tetracycline preferentially bind to amyloid in the ,-sheet conformation because both decreased the slope of the exponential growth, even if to a different extent, whereas no effect was observed for tacrine and galantamine. Some very preliminary indications can be derived about the structural requirements for binding to nonamyloidogenic or ,-sheet amyloid secondary structure for the development of potent antiaggregating agents. On these premises, memoquin, a multifunctional molecule that was designed to become a drug candidate for the treatment of Alzheimer's disease, was investigated under the reported circular dichroism assay and its anti-amyloidogenic mechanism of action was elucidated. [source] Macroeconomic News and the Euro/Dollar Exchange RateECONOMIC NOTES, Issue 3 2003Gabriele Galati This paper investigates to what extent daily movements in the euro/dollar rate were driven by news about the macroeconomic situation in the USA and the euro area during the first two years of EMU. We examine whether market participants reacted to news in different ways depending on whether the news came from the USA or from the euro area, and whether the news was good or bad. Furthermore, we investigate whether traders' reaction to news has changed over time. We find that macroeconomic news has a statistically significant correlation with daily movements of the euro against the dollar. However, this relationship exhibits considerable time variation. There are indications of asymmetric response, but to different extents at different times. Our results also provide evidence that the market seemed to ignore good news and remain fixated on bad news from the euro area, as often claimed in market commentaries, but only for some time. Finally, we find evidence that the impact of macroeconomic news on the euro/dollar rate was stronger when news switches from good to bad or vice versa. (J.E.L.: F31). [source] Co-electroosmotic capillary electrophoresis of basic proteins with 1-alkyl-3-methylimidazolium tetrafluoroborate ionic liquids as non-covalent coating agents of the fused-silica capillary and additives of the electrolyte solutionELECTROPHORESIS, Issue 11 2009Danilo Corradini Abstract The paper reports the results of a study carried out to evaluate the use of three 1-alkyl-3-methylimidazolium-based ionic liquids as non-covalent coating agents for bare fused-silica capillaries and additives of the electrolyte solutions (BGE) for CE of basic proteins in the co-EOF separation mode. The three ionic liquids are differentiated from each other by the length of the alkyl group on the imidazolium cation, consisting of either an ethyl, butyl or octyl substituent, whereas tetrafluoroborate is the common anionic component of the ionic liquids. Coating the capillary with the ionic liquid resulted in improved peak shape and protein separation, while the EOF was maintained cathodic. This indicates that each ionic liquid is effective at masking the protein interaction sites on the inner surface of the capillary, also when its adsorption onto the capillary wall has not completely neutralized all the negative charges arising from the ionization of the silanol groups and the ionic liquid is not incorporated into the BGE employed for separation. Using the coated capillaries with BGE containing the ionic liquid employed for the coating, at concentration low enough to maintaining the EOF cathodic, both peak shape and protein separation varied to different extents, based on the particular ionic liquid used and its concentration. Fast and efficient separation of the model basic protein mixture in co-electroosmotic CE is obtained with the 1-butyl-3-methylimidazolium tetrafluoroborate coated capillary and 100,mM acetate buffer (pH 4.0) containing 4.4,mM 1-butyl-3-methylimidazolium tetrafluoroborate as the BGE. [source] The Mechanism of Hydrolysis of Aryl Ether Derivatives of3-HydroxymethyltriazenesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 10 2005Emília Carvalho Abstract 1-Aryl-3-aryloxymethyl-3-methyltriazenes hydrolyse to the corresponding anilines and phenols by specific-acid-catalysed, general-acid-catalysed and pH-independent mechanisms. All compounds studied exhibit specific- and general acid catalysis, though for 5a general acid catalysis was not observed below a pH of approximately 4, while for compounds 5e,f, such catalysis was absent above a pH of approximately 5. The pH-independent pathway is observed only for those compounds, 5d,f, that contain good aryloxy nucleofugic groups. The specific-acid-catalysed pathway is supported by a solvent deuterium isotope effect (SDIE) of 0.64, consistent with a mechanism involving protonation of the substrate followed by rate-determining unimolecular decomposition of the protonated species. The kH+ values gave rise to a Hammett , value of ,0.93, reflecting the competing effect of the substituents on the protonation of the substrate and the cleavage of the aryl ether. Correlation of kH+ with the pKa of the phenol leaving group affords a ,lg of 0.3. Decomposition of the protonated intermediate proceeds via a triazenyliminium ion that can be trapped by methanol. The general-acid-catalysed process exhibits an SDIE of 1.43 and Hammett , values of 0.49, 0.84 and 1.0 for reactions catalysed by chloroacetic, formic and acetic acids, respectively. Correlation of kA with the pKa of the acid gave Brønsted , values that diminish from 0.6 for O -aryl systems that are poor nucleofuges (5a,b) to 0.2 for the best nucleofuge (5f), reflecting the different extents of proton transfer required to expel each phenol. Compounds containing powerful nucleofuges exhibit a pH-independent reaction that has an SDIE of 1.1, a Hammett , value of 3.4 and a Brønsted ,lg value of 1.4. These imply a mechanism involving displacement of the aryloxide leaving group to form a triazenyliminium ion intermediate that again was trapped as a methyl ether. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Role of Ca2+ -Activated Cl, Current in Ventricular Action Potentials of Sheep During Adrenoceptor StimulationEXPERIMENTAL PHYSIOLOGY, Issue 2 2001Arie O. Verkerk Adrenoceptor stimulation enhances repolarising and depolarising membrane currents to different extents in cardiac myocytes. We investigated the opposing effects of the repolarising Ca2+ -activated Cl, current (ICl(Ca)) and depolarising L-type Ca2+ current (ICa,L) on the action potential configuration of sheep ventricular myocytes stimulated with noradrenaline. Whole-cell current-clamp recordings revealed that noradrenaline accelerated and prolonged phase-1 repolarisation. We define the minimal potential at the end of phase-1 repolarisation as ,notch level'. Noradrenaline (1 ,M) caused the notch level to fall from 14 ± 2.6 to 7.8 ± 2.8 mV (n= 24), but left action potential duration, resting membrane potential or action potential amplitude unaffected. Whole-cell voltage-clamp recordings showed that 1 ,M noradrenaline increased both ICa,L and ICl(Ca), but it had no significant effect on the principal K+ currents. Blockage of ICl(Ca) by 0.5 mM 4,4,-diisothiocyanatostilbene-2,2,-disulphonic acid (DIDS) in both the absence and the presence of noradrenaline abolished phase-1 repolarisation. In the presence of noradrenaline, DIDS caused elevation of the plateau phase amplitude and an increase in the action potential duration. In conclusion, elevation of the plateau phase amplitude and action potential prolongation associated with an increased ICa,L upon adrenoceptor stimulation is prevented by an increased ICl(Ca) in sheep ventricular myocytes. [source] Genetic transduction in freshwater ecosystemsFRESHWATER BIOLOGY, Issue 6 2008OLADELE A. OGUNSEITAN Summary 1. Lateral genetic exchange is a profound consequence of the co-existence of viruses (bacteriophages) and bacteria in freshwater ecosystems. Transduction is distinct from other mechanisms of genetic exchange because it is driven by potentially lethal agents external to the donor and recipient cells. Therefore, transduction is reputed to be a major driving force behind the diversity in natural populations and communities of bacteria. 2. Both generalized transduction (where every segment of the donor's genome has equal chance of being transferred to a recipient cell) and specialized transduction (where certain donor gene sequences are transferred at higher frequencies than others based on their proximity to the integration site of the transducing bacteriophage genome) have been demonstrated for various freshwater bacteria. However, these genetic exchange events occur at frequencies that vary widely, from 10,2 to 10,10 transductants per recipient, depending on the influence of various physical, chemical and biotic environmental factors on the outcome of phage,host encounters. Methodological constraints limit the interpretation of results from early studies of transduction in freshwaters because those studies introduced exogenous organisms in microcosms and excluded, to different extents, naturally occurring environmental conditions and their variability. 3. To assist the design and extrapolation of empirical observations, mathematical models including application of Group Theory are useful to estimate boundaries of the impact of transduction in generating and maintaining microbial diversity in freshwater. These theoretical excursions generate hypotheses and questions that can only be answered through refinement of current empirical estimates of transduction frequency, polarity of gene mobilization, bacteriophage host ranges, and the influence of gradients in environmental parameters that characterize freshwater ecosystems. [source] Hippocampal volume and asymmetry in mild cognitive impairment and Alzheimer's disease: Meta-analyses of MRI studiesHIPPOCAMPUS, Issue 11 2009Feng Shi Abstract Numerous studies have reported a smaller hippocampal volume in Alzheimer's disease (AD) patients than in aging controls. However, in mild cognitive impairment (MCI), the results are inconsistent. Moreover, the left-right asymmetry of the hippocampus receives less research attention. In this article, meta-analyses are designed to determine the extent of hippocampal atrophy in MCI and AD, and to evaluate the asymmetry pattern of the hippocampal volume in control, MCI, and AD groups. From 14 studies including 365 MCI patients and 382 controls, significant atrophy is found in both the left [Effect size (ES), 0.92; 95% confidence interval (CI), 0.72,1.11] and right (ES, 0.78; 95% CI, 0.57,0.98) hippocampus, which is lower than that in AD (ES, 1.60, 95% CI, 1.37,1.84, in left; ES, 1.52, 95% CI, 1.31,1.72, in right). Comparing with aging controls, the average volume reduction weighted by sample size is 12.9% and 11.1% in left and right hippocampus in MCI, and 24.2% and 23.1% in left and right hippocampus in AD, respectively. The findings show a bilateral hippocampal volume loss in MCI and the extent of atrophy is less than that in AD. By comparing the left and right hippocampal volume, a consistent left-less-than-right asymmetry pattern is found, but with different extents in control (ES, 0.39), MCI (ES, 0.56), and AD (ES, 0.30) group. © 2009 Wiley-Liss, Inc. [source] Environmental isotopic and hydrochemical characteristics of groundwater systems in Daying and Qicun geothermal fields, Xinzhou Basin, Shanxi, ChinaHYDROLOGICAL PROCESSES, Issue 22 2010Dongmei Han Abstract The conceptual hydrogeological model of the low to medium temperature Daying and Qicun geothermal fields has been proposed, based on hydrochemical characteristics and isotopic compositions. The two geothermal fields are located in the Xinzhou basin of Shanxi, China and exhibit similarities in their broad-scale flow patterns. Geothermal water is derived from the regional groundwater flow system of the basin and is characterized by Cl·SO4 -Na type. Thermal water is hydrochemically distinct from cold groundwater having higher total dissolved solids (TDS) (>0·8 g/l) and Sr contents, but relatively low Ca, Mg and HCO3 contents. Most shallow groundwater belongs to local flow systems which are subject to evaporation and mixing with irrigation returns. The groundwater residence times estimated by tritium and 14C activities indicate that deep non-thermal groundwater (130,160 m) in the Daying region range from modern (post-1950s) in the piedmont area to more than 9·4 ka BP (Before Present) in the downriver area and imply that this water belong to an intermediate flow system. Thermal water in the two geothermal fields contains no detectable active 14C, indicating long residence times (>50 ka), consistent with this water being part of a large regional flow system. The mean recharge elevation estimated by using the obtained relationship Altitude (m) = , 23·8 × ,2H (, ) , 121·3, is 1980 and 1880 m for the Daying and Qicun geothermal fields, respectively. The annual infiltration rates in the Daying and Qicun geothermal fields can be estimated to be 9029 × 103 and 4107 × 103 m3/a, respectively. The variable 86Sr/87Sr values in the thermal and non-thermal groundwater in the two fields reflect different lithologies encountered along the flow path(s) and possibly different extents of water-rock interaction. Based on the analysis of groundwater flow systems in the two geothermal fields, hydrogeochemical inverse modelling was performed to indicate the possible water-rock interaction processes that occur under different scenarios. Copyright © 2010 John Wiley & Sons, Ltd. [source] Classification of cancer types by measuring variants of host response proteins using SELDI serum assaysINTERNATIONAL JOURNAL OF CANCER, Issue 5 2005Eric T. Fung Abstract Protein expression profiling has been increasingly used to discover and characterize biomarkers that can be used for diagnostic, prognostic or therapeutic purposes. Most proteomic studies published to date have identified relatively abundant host response proteins as candidate biomarkers, which are often dismissed because of an apparent lack of specificity. We demonstrate that 2 host response proteins previously identified as candidate markers for early stage ovarian cancer, transthyretin and inter-alpha trypsin inhibitor heavy chain 4 (ITIH4), are posttranslationally modified. These modifications include proteolytic truncation, cysteinylation and glutathionylation. Assays using Surface Enhanced Laser Desorption/Ionization Time of Flight Mass Spectrometry (SELDI-TOF-MS) may provide a means to confer specificity to these proteins because of their ability to detect and quantitate multiple posttranslationally modified forms of these proteins in a single assay. Quantitative measurements of these modifications using chromatographic and antibody-based ProteinChip® array assays reveal that these posttranslational modifications occur to different extents in different cancers and that multivariate analysis permits the derivation of algorithms to improve the classification of these cancers. We have termed this process host response protein amplification cascade (HRPAC), since the process of synthesis, posttranslational modification and metabolism of host response proteins amplifies the signal of potentially low-abundant biologically active disease markers such as enzymes. © 2005 Wiley-Liss, Inc. [source] Effects of pulsed electric fields on bioactive components, colour and flavour of green tea infusionsINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 2 2009Wei Zhao Summary Green tea is an unfermented tea containing a higher quantity of bioactive components. In this paper, the effects of pulsed electric field (PEF) treatments on the bioactive components (polyphenols, catechins and free amino acids), colour and flavour of green tea infusions were studied. PEF as a promising non-thermal sterilisation technology could efficiently retain polyphenols, catechins and original colour of green tea infusions with electric field strength from 20 to 40 kV cm,1 for 200 ,s. PEF treatments caused a significant increase in the total free amino acids of green tea infusions. The total free amino acids increased by 7.5% after PEF treatment at 40 kV cm,1. The increase in total amino acids induced by PEF treatment, especially to theanine, is beneficial for the quality of commercial ready-to-drink green tea infusion products. There was no significant effect of PEF treatment at 20 or 30 kV cm,1 on flavour compounds of green tea infusions. However, PEF treatment caused losses of volatiles in green tea infusions to different extents when PEF dosage was higher than a critical level. The total concentration of volatiles lost was approximately 10% after PEF treatment at 40 kV cm,1 for 200 ,s. [source] Evolution of the structure and function of the vertebrate tongueJOURNAL OF ANATOMY, Issue 1 2002Shin-ichi Iwasaki Abstract Studies of the comparative morphology of the tongues of living vertebrates have revealed how variations in the morphology and function of the organ might be related to evolutional events. The tongue, which plays a very important role in food intake by vertebrates, exhibits significant morphological variations that appear to represent adaptation to the current environmental conditions of each respective habitat. This review examines the fundamental importance of morphology in the evolution of the vertebrate tongue, focusing on the origin of the tongue and on the relationship between morphology and environmental conditions. Tongues of various extant vertebrates, including those of amphibians, reptiles, birds and mammals, were analysed in terms of gross anatomy and microanatomy by light microscopy and by scanning and transmission electron microscopy. Comparisons of tongue morphology revealed a relationship between changes in the appearance of the tongue and changes in habitat, from a freshwater environment to a terrestrial environment, as well as a relationship between the extent of keratinization of the lingual epithelium and the transition from a moist or wet environment to a dry environment. The lingual epithelium of amphibians is devoid of keratinization while that of reptilians is keratinized to different extents. Reptiles live in a variety of habitats, from seawater to regions of high temperature and very high or very low humidity. Keratinization of the lingual epithelium is considered to have been acquired concomitantly with the evolution of amniotes. The variations in the extent of keratinization of the lingual epithelium, which is observed between various amniotes, appear to be secondary, reflecting the environmental conditions of different species. [source] Analysis of SOX10 mutations identified in Waardenburg-Hirschsprung patients: Differential effects on target gene regulationJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 3 2003Kwok Keung Chan Abstract SOX10 is a member of the SOX gene family related by homology to the high-mobility group (HMG) box region of the testis-determining gene SRY. Mutations of the transcription factor gene SOX10 lead to Waardenburg-Hirschsprung syndrome (Waardenburg-Shah syndrome, WS4) in humans. A number of SOX10 mutations have been identified in WS4 patients who suffer from different extents of intestinal aganglionosis, pigmentation, and hearing abnormalities. Some patients also exhibit signs of myelination deficiency in the central and peripheral nervous systems. Although the molecular bases for the wide range of symptoms displayed by the patients are still not clearly understood, a few target genes for SOX10 have been identified. We have analyzed the impact of six different SOX10 mutations on the activation of SOX10 target genes by yeast one-hybrid and mammalian cell transfection assays. To investigate the transactivation activities of the mutant proteins, three different SOX target binding sites were introduced into luciferase reporter gene constructs and examined in our series of transfection assays: consensus HMG domain protein binding sites; SOX10 binding sites identified in the RET promoter; and Sox10 binding sites identified in the P0 promoter. We found that the same mutation could have different transactivation activities when tested with different target binding sites and in different cell lines. The differential transactivation activities of the SOX10 mutants appeared to correlate with the intestinal and/or neurological symptoms presented in the patients. Among the six mutant SOX10 proteins tested, much reduced transactivation activities were observed when tested on the SOX10 binding sites from the RET promoter. Of the two similar mutations X467K and 1400del12, only the 1400del12 mutant protein exhibited an increase of transactivation through the P0 promoter. While the lack of normal SOX10 mediated activation of RET transcription may lead to intestinal aganglionosis, overexpression of genes coding for structural myelin proteins such as P0 due to mutant SOX10 may explain the dysmyelination phenotype observed in the patients with an additional neurological disorder. © 2003 Wiley-Liss, Inc. [source] Sorption of tannic acid on zirconium pillared clayJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 1 2002P Vinod Abstract Zirconium pillared clay (PILC) was prepared using montmorillonite as the base clay. Adsorption of tannic acid (tannin) was studied by a batch equilibrium technique, as a function of adsorbate concentration, temperature, pH, agitation speed, particle size of the adsorbent and ionic strength. The process of uptake is governed by diffusion controlled first-order reversible rate kinetics. The higher uptake for the pH range 4.0,6.0 was attributed to external hydrogen bonding between phenolic-OH groups of tannin molecules and the hydrogen bonding sites on the clay. The removal of tannin by adsorption was found to be >99.0% depending on the initial concentration in the pH range of 4.0,6.0. The process involves both film and pore diffusion to different extents. The effects of solute concentration, temperature, agitation speed and particle size on the diffusion rate were investigated. Tannin uptake was found to increase with ionic strength due to the compression of diffuse double layers. The applicability of Langmuir and Freundlich isotherm models has been tested. The maximum adsorption capacity of PILC was found to be 45.8,µmol,g,1 of clay and the affinity constant is 2.9,×,10,2,dm3,µmol,1 at 30,°C. Thermodynamic parameters such as ,G,°,,H,° and ,S,° were calculated to predict the nature of adsorption. The isosteric enthalpies of adsorption were also determined and found to decrease with increasing surface coverage. Regeneration with hot water (60,°C) has been investigated for several cycles with a view to recovering the adsorbed tannin and also restoring the sorbent to its original state. Copyright © 2001 Society of Chemical Industry [source] | ||||||||||||||||||||||||||||||||||