Home About us Contact
|
Home About us Contact | ||
|
|
||
Significant Loss (significant + loss)
Selected AbstractsGrass cells ingested by ruminants undergo autolysis which differs from senescence: implications for grass breeding targets and livestock productionPLANT CELL & ENVIRONMENT, Issue 10 2002E. M. Beha Abstract It is widely believed that the initial degradation of proteins contained in grazed forage is mediated by rumen micro-organisms, but the authors' recent work suggests that the plant cells themselves contribute to their own demise. In the present study the responses of Lolium perenne leaves to the rumen environment were investigated by using an in vitro system which simulates the main stresses of the rumen but from which rumen micro-organisms were excluded. Degradation of leaf protein and the accumulation of amino acids in tissue and bathing medium occurred over a time-scale that is relevant to rumen function, and in a near 1 : 1 ratio. Significant loss of nuclear material was observed after 6 h incubation and chloroplasts became morphologically more spherical as the incubation progressed. In situ localization suggested that ribulose 1,5 bisphosphate carboxylase/oxygenase was broken down within chloroplasts which from cytology were judged to be intact. We conclude from these data that plant metabolism may play a significant role in breaking down plant proteins within relatively intact organelles in the rumen. The determinations of chlorophyll content and cell viability revealed that the plant processes occurring in the simulated rumen were similar but not identical to those of natural senescence. [source] Poly(L-lysine) as a model drug macromolecule with which to investigate secondary structure and membrane transport, part I: physicochemical and stability studiesJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 3 2002Montakarn Chittchang Low oral bioavailability of therapeutic peptides and proteins generally results from their poor permeability through biological membranes and enzymatic degradation in the gastrointestinal tract. Since different secondary structures exhibit different physicochemical properties such as hydrophobicity, size and shape, changing the secondary structure of a therapeutic polypeptide may be another approach to increasing its membrane permeation. Poly(L-lysine) was used as a model polypeptide. The objectives of this study were to induce secondary structural changes in poly(L-lysine) and to determine the time course over which a given conformer was retained. In addition, the hydrophobicity of each secondary structure of poly(L-lysine) was assessed. The circular dichroism (CD) studies demonstrated that the conditions employed could successfully induce the desired secondary structural changes in poly(L-lysine). The ,-helix conformer appeared to be more stable at 25° C whereas the ,-sheet conformer could be preserved at 37° C. On the other hand, the random coil conformer was retained at both temperatures. Significant losses of the ,-helix and the ,-sheet conformers were observed when the pH was reduced. The change in ionic strength did not affect any of the conformers. The octanol/buffer partitioning studies indicated that the ,-helix and the ,-sheet conformers exhibited significantly different (P< 0.05) hydrophobicities. In conclusion, variation of pH and temperature conditions can be used to induce secondary structural changes in poly(L-lysine). These changes are reversible when the stimuli are removed. The ,-helix and the ,-sheet conformers of poly(L-lysine) are more lipophilic than the native random coil conformer. Thus, poly(L-lysine) may represent an ideal model polypeptide with which to further investigate the effects of secondary structure on membrane diffusion or permeation. [source] Blanching and long-term freezing affect various bioactive compounds of vegetables in different waysJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 14 2003Riitta Puupponen-Pimiä Abstract An extensive study on the effects of blanching/freezing and long-term freezer storage on various bioactive compounds of more than 20 commonly used vegetables was performed. Effects were strongly plant species-dependent. Contents of dietary fibre components either were not affected or increased slightly. Minerals in general were also stable, but some losses of soluble minerals by leaching were observed. Phenolic antioxidants and vitamins were clearly more sensitive. Significant losses (20,30%) of antioxidant activity and total phenolics were detected in many vegetables. A qualitative HPLC profiling method for phenolic antioxidants was developed which proved to be very useful when evaluating the complex behaviour of phenolics during food processing. Up to one-third of vitamin C contents were lost during blanching, and further slight losses were detected during storage. Folic acid turned out to be very sensitive to blanching, with more than half of the vitamin being lost, but was stable during freezer storage. Carotenoids and sterols were not affected by blanching or freezer storage. The usefulness of the applied screening methods for evaluation of the effects of processing on vegetables is shown. Copyright © 2003 Society of Chemical Industry [source] Analysis of microsatellite alterations in gastric carcinoma using the crypt isolation techniqueTHE JOURNAL OF PATHOLOGY, Issue 2 2004Yu-Fei Jiao Abstract The crypt isolation technique was used to analyse loss of heterozygosity (LOH) and microsatellite instability (MSI) in gastric carcinomas (36 intestinal type, 17 solid type, and 23 diffuse type) using a polymerase chain reaction assay. Increased LOH frequencies and fractional allelic losses (FAL) were observed in samples prepared using the crypt isolation technique compared with those isolated by the conventional method. A significant increase in LOH was found at several chromosomal loci, and significant differences in FAL were found in patients with intestinal- and solid-type tumours. There was no difference in the frequency of MSI using either technique. In samples prepared by the crypt isolation technique, significant allelic losses (,50%) were observed at most loci tested in intestinal- and solid-type tumours, but not in diffuse-type tumours. Significant losses of some of these loci are novel findings for gastric cancer. FAL values were significantly higher in intestinal- and solid-type tumours than in diffuse-type tumours. MSI-high was observed in intestinal- (17%) and solid-type (12%) tumours. The results suggest that the crypt isolation technique is useful for accurate allelic loss analysis in gastric carcinoma and that LOH and MSI are more common in intestinal- and solid-type tumours than in diffuse-type tumors. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [source] Glass Transition Temperatures and Fermentative Activity of Heat-Treated Commercial Active Dry YeastsBIOTECHNOLOGY PROGRESS, Issue 2 2000Carolina Schebor Differential scanning calorimetry thermograms of various samples of commercial instant active dry yeasts revealed a clear glass transition typical of amorphous carbohydrates and sugars. The resulting glass transition temperatures were found to decrease with increasing moisture content. The observed glass curve was similar to that of pure trehalose, which is known to accumulate in large amounts in baker's yeast. The effect of heat treatment at various temperatures on the fermentative activity (as measured by the metabolic production of CO2) of dry yeast was studied. First-order plots were obtained representing the loss of fermentative activity as a function of heating time at the various temperatures assayed. Significant losses of fermentative activity were observed in vitrified yeast samples. The dependence of rate constants with temperature was found to follow Arrhenius behavior. The relationship between the loss of fermentative activity and glass transition was not verified, and the glass transition was not reflected on the temperature dependence of fermentative activity loss. [source] Fast Volume Rendering and Data Classification Using Multiresolution in Min-Max OctreesCOMPUTER GRAPHICS FORUM, Issue 3 2000Feng Dong Large-sized volume datasets have recently become commonplace and users are now demanding that volume-rendering techniques to visualise such data provide acceptable results on relatively modest computing platforms. The widespread use of the Internet for the transmission and/or rendering of volume data is also exerting increasing demands on software providers. Multiresolution can address these issues in an elegant way. One of the fastest volume-rendering alrogithms is that proposed by Lacroute & Levoy 1 , which is based on shear-warp factorisation and min-max octrees (MMOs). Unfortunately, since an MMO captures only a single resolution of a volume dataset, this method is unsuitable for rendering datasets in a multiresolution form. This paper adapts the above algorithm to multiresolution volume rendering to enable near-real-time interaction to take place on a standard PC. It also permits the user to modify classification functions and/or resolution during rendering with no significant loss of rendering speed. A newly-developed data structure based on the MMO is employed, the multiresolution min-max octree, M 3 O, which captures the spatial coherence for datasets at all resolutions. Speed is enhanced by the use of multiresolution opacity transfer functions for rapidly determining and discarding transparent dataset regions. Some experimental results on sample volume datasets are presented. [source] Feature Extraction for Traffic Incident Detection Using Wavelet Transform and Linear Discriminant AnalysisCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 4 2000A. Samant To eliminate false alarms, an effective traffic incident detection algorithm must be able to extract incident-related features from the traffic patterns. A robust feature-extraction algorithm also helps reduce the dimension of the input space for a neural network model without any significant loss of related traffic information, resulting in a substantial reduction in the network size, the effect of random traffic fluctuations, the number of required training samples, and the computational resources required to train the neural network. This article presents an effective traffic feature-extraction model using discrete wavelet transform (DWT) and linear discriminant analysis (LDA). The DWT is first applied to raw traffic data, and the finest resolution coefficients representing the random fluctuations of traffic are discarded. Next, LDA is employed to the filtered signal for further feature extraction and reducing the dimensionality of the problem. The results of LDA are used as input to a neural network model for traffic incident detection. [source] Problems For Semantic Externalism and A Priori Refutations of Skeptical ArgumentsDIALECTICA, Issue 1 2000Keith Butler Summary A familiar sort of argument for skepticism about the external world appeals to the evidential similarity between what is presumed to be the normal case and the case where one is a brain in a vat (or BIV). An argument from Putnam (1981, ch. 1) has been taken by many to provide an a priori refutation of this sort of skeptical argument. The question I propose to address in this paper is whether Putnam's argument affords us an a priori refutation of skeptical arguments that appeal to the claim that one does not know that one is not a BIV. I will develop a negative answer to this question along two related fronts. Along the first front I defend against new criticisms the common position that the externalism on which Putnam's argument is based entails skepticism about the meanings of sentences in our language and the contents of our thoughts. I do not take this to be a refutation of externalism or externalist arguments; rather, I see this as a motivation to locate the difficulty with arguments for externalism. But if externalism is abandoned, of course, the anti-skeptical argument it has widely been taken to support must be abandoned along with it. I will argue, however, that this is not a significant loss, because along a second front I will argue that externalism cannot be given a priori justification; it is therefore ill-suited to ground an a priori refutation of BIV skepticism anyway. [source] Aqueous photolysis of 8:2 fluorotelomer alcoholENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2005Suzanne A. Gauthier Abstract The 8:2 fluorotelomer alcohol (8:2 FTOH) was photodegraded in aqueous hydrogen peroxide solutions, synthetic field water (SFW) systems, and Lake Ontario (Canada) water samples. It was found to undergo indirect photolysis, with the data suggesting that the hydroxyl radical was the main degradation agent and that nitrate promoted photolysis whereas dissolved organic carbon inhibited it. The half-lives of 8:2 FTOH were 0.83 ± 0.20 h (10 mM H2O2), 38.0 ± 6.0 h (100 ,M H2O2), 30.5 ± 8.0 to 163.1 ± 3.0 h (SFW systems), and 93.2 ± 10.0 h (Lake Ontario). No significant loss of the parent compound by direct photolysis could be observed. The major monitored products were the 8:2 fluorotelomer aldehyde, the 8:2 fluorotelomer acid (8:2 FTCA), and perfluorooctanoate (PFOA); the minor monitored products were the 8:2 fluorotelomer unsaturated acid (8:2 FTUCA) and perfluorononanoate (PFNA). The intermediates, 8:2 FTCA and 8:2 FTUCA, were photodegraded to verify the degradation pathway, and a mechanism for the photolysis was proposed whereby the end products of the photolysis pathway were PFOA (major) and PFNA (minor). [source] Long-term survey of laryngoplasty and ventriculocordectomy in an older, mixed-breed population of 200 horses.EQUINE VETERINARY JOURNAL, Issue 4 2003Part 1: Maintenance of surgical arytenoid abduction, complications of surgery Summary Reasons for performing study: Laryngoplasty (LP) is currently the most common surgical treatment for equine laryngeal paralysis, however, there have been no reports quantifying the degree of retention of arytenoid abduction following L P. ADitionally, the complications of LP have been poorly documented. Objectives: To record the degree of arytenoid abduction retention following LP and to accurately document all complications of surgery. Methods: A study (1986,1998) of 200 horses of mixed breed and workload, median age 6 years (prospective 136 cases and retrospective 64 cases) undergoing LP (using 2 stainless steel wires) and combined ventriculocordectomy was undertaken; 198 owners completed questionnaires, a median of 19 months following surgery. The degree of arytenoid abduction achieved was endoscopically, semi-quantitatively evaluated using a 5-grade system, at 1 day, 7 days, and 6 weeks after surgery. Results: On the day following LP, 62% of horses had good (median grade 2) arytenoid abduction, 10% had excessive (grade 1), and 5% had minimal (grade 4) abduction (overall - median grade 2). Due to progressive loss of abduction, moderate (median grade 3, range 1,5) abduction was present overall at 1 and 6 weeks after LP. Further surgery was required to re-tighten prostheses in 10% of cases with excessive loss of abduction, or to loosen prostheses in 7% of horses which had continuing high levels of LP abduction and significant post operative dysphagia. LP wound problems (mainly seromas and suture abscesses) were reported to last <2 weeks in 9% of cases, <4 weeks in 4% and >4 weeks in 4%. The (partially sutured) laryngotomy wounds discharged post operatively for <2 weeks in 22% of cases, <4 weeks in 7% and for >4 weeks in 2%. Coughing occurred at some stage post operatively in 43% of cases and its presence correlated significantly with the degree of surgical arytenoid abduction. This coughing occurred during eating in 24% of cases and was not associated with eating (or dysphagia) in the other 19% of cases. Chronic (>6 months duration) coughing occurred in 14% of cases, but appeared to be due to intercurrent pulmonary disease in half of these horses. Conclusions: Suturing the cricotracheal membrane allows most laryngotomy wounds to heal quickly. Laryngoplasty wound problems were of little long-term consequence when stainless steel wire prostheses were used. Potential relevance: A significant loss of LP abduction occurs in most horses in the 6 weeks following surgery and efforts should be made to find ways to prevent such loss. However, excessive LP abduction is associated with post operative dysphagia and coughing. [source] Glial cell loss, proliferation and replacement in the contused murine spinal cordEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 6 2007Judith M. Lytle Abstract Studies in the rat have shown that contusive spinal cord injury (SCI) results in devastating pathology, including significant loss of mature oligodendrocytes and astrocytes even in spared white matter. Subsequently, there is increased proliferation of endogenous NG2+ cells, postulated to contribute to replacement of mature glia chronically, which is important for functional recovery. Studies of mechanisms that stimulate endogenous progenitor cells would be facilitated by using mouse models with naturally occurring and genetically engineered mutations. To determine whether the murine response is similar to that in the rat, we performed contusive SCI on adult female C57Bl/6 mice at the T8,9 level. Animals received bromodeoxyuridine injections in the first week following injury and were killed at 1, 3, 4, 7 or 28 days postinjury (DPI). The overall loss of macroglia and the temporal,spatial response of NG2+ cells after SCI in the (C57Bl/6) mouse was very similar to that in the (Sprague,Dawley) rat. By 24 h after SCI nearly half of the macroglia in spared ventral white matter had been lost. Cell proliferation was increased at 1,7 DPI, peaking at 3,4 DPI. Dividing cells included NG2+ cells and Cd11b+ macrophages and microglia. Furthermore, cells dividing in the first week expressed markers of mature glia at 28 DPI. The similarities in endogenous progenitor cell response to SCI in the mouse and rat suggest that this is a fundamental injury response, and that transgenic mouse models may be used to further probe how this cellular response to SCI might be enhanced to improve recovery after SCI. [source] The role of NGF uptake in selective vulnerability to cell death in ageing sympathetic neuronsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2004Kliment P. Gatzinsky Abstract We have examined the hypothesis that differences in nerve growth factor (NGF) uptake and transport determine vulnerability to age-related neurodegeneration. Neurons projecting to cerebral blood vessels (CV) in aged rats are more vulnerable to age-related degeneration than those projecting to the iris. Uptake of NGF was therefore examined in sympathetic neurons projecting from the superior cervical ganglion (SCG) to CV and iris in young and old rats by treating the peripheral processes of these neurons with different doses of I125 -NGF. Total uptake of I125 -NGF was reduced in old CV-projecting, but not iris-projecting, neurons. Numbers of radiolabelled neurons projecting to each target were counted in sectioned ganglia. The data showed age-related reductions in numbers of labelled neurons projecting to CV, but no change in numbers of neurons projecting to the iris. Calculation of uptake of I125 -NGF per neuron unexpectedly showed no major age-related differences in either of the two neuron populations. However, uptake per neuron was considerably lower for young and old CV-projecting, compared to iris-projecting, SCG neurons. We hypothesized that variations in NGF uptake might affect neuronal survival in old age. Counts of SCG neurons using a physical disector following retrograde tracing with Fluorogold confirmed the selective vulnerability of CV-projecting neurons by showing a significant 37% loss of these neurons in the period between 15 and 24 months. In contrast, there was no significant loss of iris-projecting neurons. We conclude that vulnerability to, or protection from, age-related neurodegeneration and neuronal cell death are associated with life-long low, or high, levels of NGF uptake, respectively. [source] Injury induced c-Jun expression and phosphorylation in the dopaminergic nigral neurons of the rat: correlation with neuronal death and modulation by glial-cell-line-derived neurotrophic factorEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 1 2001Elisabetta Vaudano Abstract This study was designed to determine whether induction and phosphorylation of the transcription factor c-Jun is associated with lesion-induced death of dopaminergic neurons of the substantia nigra pars compacta, and if this cellular response is modulated by glial-cell-line-derived neurotrophic factor. In adult rats, delayed dopaminergic neuron cell death induced by intrastriatal 6-hydroxydopamine injection led to a marked increase in the number of both c-Jun- and phosphorylated c-Jun-immunoreactive nuclei in the substantia nigra pars compacta. The response was maximal before any significant loss of nigral neurons could be detected (on day 7 post lesion) and was confined to the dopaminergic neurons. Similarly, 6-hydroxydopamine lesion of the striatal dopaminergic terminals or excitotoxic lesion of the striatal target neurons in neonatal rats resulted in an increased number of c-Jun- and phosphorylated c-Jun-immunoreactive nigral nuclei that preceded the loss of nigral dopaminergic neurons. By contrast, after an excitotoxic lesion of the striatal target neurons in the adult rat, resulting in atrophy but not cell death of the nigral dopaminergic neurons, no upregulation of either c-Jun or phosphorylated c-Jun was found. A single injection of 10 µg of glial-cell-line-derived-neurotrophic factor given at day 3 after the intrastriatal 6-hydroxydopamine lesion reduced the number of c-Jun- and phosphorylated c-Jun-immunoreactive nuclei in the substantia nigra and protected the dopaminergic neurons from the ensuing cell death. We conclude that c-Jun induction and phosphorylation may be involved in the cellular events leading to death of nigral dopaminergic neurons in vivo and that this response can be modulated by glial-cell-line-derived-neurotrophic factor. [source] A Magnetically Separable Heterogeneous Deallylation Catalyst: [CpRu(,3 -C3H5)(2-pyridinecarboxylato)]PF6 Complex Supported on a Ferromagnetic Microsize Particle Fe3O4@SiO2EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 6 2009Takuya Hirakawa Abstract The highly reactive and chemoselective homogeneousdeallylation catalyst CpRu(,3 -C3H5)(4-substituted-2-pyridinecarboxylato) was immobilized on microsize spherical Fe3O4@SiO2 particles. The resultant heterogeneous catalyst displays high saturation magnetization, weak coercive forces and high levels of dispersibility. The catalyst has increased the utility of deallylation by allowing the reaction to be conducted without extra additives. The only co-product of the reaction is a volatile allyl ether compound. Here, we demonstrate the efficient deallylation and separation of highly polar multifunctional compounds as well as multiple rounds of catalyst recycling without significant loss of reactivity. The usefulness of this catalyst has been confirmed by the synthesis of a triribonucleotide 3,5 U. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Polymer-Immobilized Pyrrolidine-Based Chiral Ionic Liquids as Recyclable Organocatalysts for Asymmetric Michael Additions to Nitrostyrenes under Solvent-Free Reaction ConditionsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 7 2008Pinhua Li Abstract A polymer immobilized pyrrolidine-based chiral ionic liquid 5a was synthesized and was found to be a highly efficient catalyst for the Michael additions of ketones and aldehydes to nitrostyrenes, which afforded the corresponding adducts in good yields (up to 97,%), excellent enantioselectivities (up to >99,% ee) and high diastereoselectivities (up to >99:1 dr) under solvent-free reaction conditions. In addition, the catalyst 5a could be reused at least eight times without a significant loss of its catalytic activity and stereoselectivity.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] POSTGLACIAL DISPERSAL OF THE EUROPEAN RABBIT (ORYCTOLAGUS CUNICULUS) ON THE IBERIAN PENINSULA RECONSTRUCTED FROM NESTED CLADE AND MISMATCH ANALYSES OF MITOCHONDRIAL DNA GENETIC VARIATIONEVOLUTION, Issue 4 2002Madalena Branco Abstract Nested clade analysis was applied to cytochrome b restriction site data previously obtained on 20 natural populations of the European rabbit across the Iberian Peninsula to test the hypothesis of postglacial dispersal from two main refugia, one in the northeast and the other in the southwest. Apart from historical fragmentation that resulted in geographic discontinuity of two distinct mitochondrial DNA (mtDNA) clades A and B, patterns of haplotype genetic variability have been shaped mostly by restricted gene flow via isolation by distance. The distribution of tip versus interior haplotypes suggests that dispersal occurred from both the southwestern and northeastern groups. Dispersal from the southwest had a north and northwest direction, whereas from the northeast it had mostly a western and southern orientation, with subsequent overlap in a southeastern-northwestern axis across the Iberian Peninsula. The analysis of the pairwise mismatch distribution of a 179,181-bp fragment of the mtDNA control region, for seven of those populations, further supports the idea that major patterns of dispersal were in the direction of central Iberia. Additionally, rabbit populations do not show signs of any significant loss of genetic diversity in the recent past, implying that they maintained large population sizes and structure throughout the ice ages. This is congruent with the fact that the Iberian Peninsula was itself a glacial refugium during Quaternary ice ages. Nonetheless, climatic oscillations of this period, although certainly milder than in northern Europe, were sufficient to affect the range distributions of Iberian organisms. [source] Stream food web response to a salmon carcass analogue addition in two central Idaho, U.S.A. streamsFRESHWATER BIOLOGY, Issue 3 2008ANDRE E. KOHLER Summary 1. Pacific salmon and steelhead once contributed large amounts of marine-derived carbon, nitrogen and phosphorus to freshwater ecosystems in the Pacific Northwest of the United States of America (California, Oregon, Washington and Idaho). Declines in historically abundant anadromous salmonid populations represent a significant loss of returning nutrients across a large spatial scale. Recently, a manufactured salmon carcass analogue was developed and tested as a safe and effective method of delivering nutrients to freshwater and linked riparian ecosystems where marine-derived nutrients have been reduced or eliminated. 2. We compared four streams: two reference and two treatment streams using salmon carcass analogue(s) (SCA) as a treatment. Response variables measured included: surface streamwater chemistry; nutrient limitation status; carbon and nitrogen stable isotopes; periphyton chlorophyll a and ash-free dry mass (AFDM); macroinvertebrate density and biomass; and leaf litter decomposition rates. Within each stream, upstream reference and downstream treatment reaches were sampled 1 year before, during, and 1 year after the addition of SCA. 3. Periphyton chlorophyll a and AFDM and macroinvertebrate biomass were significantly higher in stream reaches treated with SCA. Enriched stable isotope (,15N) signatures were observed in periphyton and macroinvertebrate samples collected from treatment reaches in both treatment streams, indicating trophic transfer from SCA to consumers. Densities of Ephemerellidae, Elmidae and Brachycentridae were significantly higher in treatment reaches. Macroinvertebrate community composition and structure, as measured by taxonomic richness and diversity, did not appear to respond significantly to SCA treatment. Leaf breakdown rates were variable among treatment streams: significantly higher in one stream treatment reach but not the other. Salmon carcass analogue treatments had no detectable effect on measured water chemistry variables. 4. Our results suggest that SCA addition successfully increased periphyton and macroinvertebrate biomass with no detectable response in streamwater nutrient concentrations. Correspondingly, no change in nutrient limitation status was detected based on dissolved inorganic nitrogen to soluble reactive phosphorus ratios (DIN/SRP) and nutrient-diffusing substrata experiments. Salmon carcass analogues appear to increase freshwater productivity. 5. Salmon carcass analogues represent a pathogen-free nutrient enhancement tool that mimics natural trophic transfer pathways, can be manufactured using recycled fish products, and is easily transported; however, salmon carcass analogues should not be viewed as a replacement for naturally spawning salmon and the important ecological processes they provide. [source] Avifauna response to hurricanes: regional changes in community similarityGLOBAL CHANGE BIOLOGY, Issue 3 2010CHADWICK D. RITTENHOUSE Abstract Global climate models predict increases in the frequency and intensity of extreme climatic events such as hurricanes, which may abruptly alter ecological processes in forests and thus affect avian diversity. Developing appropriate conservation measures necessitates identifying patterns of avifauna response to hurricanes. We sought to answer two questions: (1) does avian diversity, measured as community similarity, abundance, and species richness, change in areas affected by hurricane compared with unaffected areas, and (2) what factors are associated with the change(s) in avian diversity? We used North American Breeding Bird Survey data, hurricane track information, and a time series of Landsat images in a repeated measures framework to answer these questions. Our results show a decrease in community similarity in the first posthurricane breeding season for all species as a group, and for species that nest in the midstory and canopy. We also found significant effects of hurricanes on abundance for species that breed in urban and woodland habitats, but not on the richness of any guild. In total, hurricanes produced regional changes in community similarity largely without significant loss of richness or overall avian abundance. We identified several potential mechanisms for these changes in avian diversity, including hurricane-induced changes in forest habitat and the use of refugia by birds displaced from hurricane-damaged forests. The prospect of increasing frequency and intensity of hurricanes is not likely to invoke a conservation crisis for birds provided we maintain sufficient forest habitat so that avifauna can respond to hurricanes by shifting to areas of suitable habitat. [source] E-cadherin abnormalities resulting from CPG methylation promoter in metastatic and nonmetastatic oral cancerHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 1 2008Renato Vieira de Moraes MSc Abstract Background. This study aims to compare the alterations in the methylation profiles of E-cadherin in oral cancer, especially in tumors with lowest metatastic potential. Methods. Nine oral verrucous carcinomas (VCs), 20 oral well-differentiated squamous cell carcinomas without lymph node involvement (SCC-pN0), and 17 with lymph node involvement (SCC-pN+) were analyzed using methylation-specific polymerase chain reaction and immunohistochemical expression of E-cadherin gene. Results. The immunohistochemical expression of E-cadherin in VC was significantly higher (p = .016) when compared with SCC-pN0 and SCC-pN+ groups. The E-cadherin gene methylation was not correlated with its abnormal immunohistochemical expression in VC and SCC-pN0. All tumors of the SCC-pN+ group with unmethylated E-cadherin gene showed significant loss of E-cadherin immunoexpression (p = .044). Conclusions. The E-cadherin gene methylation presence in tumors with lowest invasive and metastatic potential, such as VC, suggests the early involvement of this epigenetic event in the multistep progression of the oral carcinogenesis. © 2007 Wiley Periodicals, Inc. Head Neck, 2008 [source] Fair Trade Community CaféACCOUNTING PERSPECTIVES, Issue 2 2010KAREN LIGHTSTONE capitaux propres; erreurs comptables; petite entreprise; rentabilité Abstract This case concerns the real operations of a café in a small town in Nova Scotia, Canada. It is a second location of a theme restaurant, with the first location successfully operating for a number of years. The owner of the first location, and senior partner of the second café, is available for advice but does not participate in the day-to-day operations of the second location; there are two junior partners who run the business. The focus is on the financial statements generated by an external bookkeeping service. The income statement reports a significant loss, and some of the accounts on the balance sheet and income statement do not make sense for this type of business. Simple ratio and variance analysis provides information for students to determine where problems lie. The case presents a good opportunity for students who have a basic understanding of financial statements to read a set of real statements generated by a bookkeeping service. Not all transactions are logical for a small café, although the financial information is from a real café in operation. The case also contains industry information on the operations of small food and drinking businesses located in Nova Scotia. Fair Trade Community Café Résumé Le cas exposé par l'auteure a trait à l'exploitation d'un véritable café situé dans une petite ville de Nouvelle-Écosse, au Canada. Il s'agit du second établissement d'un restaurant à thème dont le premier établissement exerce ses activités avec succès depuis plusieurs années. Le propriétaire du premier établissement, et associé majoritaire du second, est disposéà prodiguer des conseils mais ne participe pas à l'exploitation quotidienne du second café, que dirigent deux associés minoritaires. Le cas porte sur les états financiers produits par un service externe de tenue des comptes. Le compte de résultat fait état d'une perte importante, et certains des comptes du bilan et des postes du compte de résultat ne conviennent pas à ce type d'entreprise. Une simple analyse des ratios et des écarts fournit de l'information permettant aux étudiants de diagnostiquer les problèmes qui se posent. Le cas offre aux étudiants possédant une connaissance de base de la façon dont les états financiers sont établis une excellente occasion de lire un jeu d'états financiers véritables, produits par un service de tenue des comptes. Toutes les opérations ne sont pas logiquement celles d'un petit café, bien que les données financières proviennent d'un établissement authentique. Le cas contient également des informations sectorielles sur les activités de petites entreprises du secteur de l'alimentation établies en Nouvelle-Écosse. [source] Impact of spatial variations of land surface parameters on regional evaporation: a case study with remote sensing dataHYDROLOGICAL PROCESSES, Issue 9 2001Hussein O. Farah Abstract Most precipitation in watersheds is consumed by evaporation, thus techniques to appraise regional evaporation are important to assess the availability of water resources. Many algorithms to estimate evaporation from remotely sensed spectral data have been developed in the recent past. In addition to differences in the physical parameterization of surface fluxes, these algorithms have different solutions for describing spatial variations of the parameters in the soil,vegetation,atmosphere,transfer (SVAT) continuum. In this study, the necessity to spatially distinguish SVAT parameters for computing surface heat fluxes is analysed for the Naivasha watershed in the Kenyan Rift Valley. Landsat Thematic Mapper (TM) spectral data have been used to first delineate the watershed into 15 hydrological units using surface temperature, normalized difference vegetation index and surface albedo as attributes. Thereafter, semi-empirical relationships between these TM-based parameters and other SVAT parameters have been applied to compute the spatial variation of SVAT parameters and the associated evaporation from the different hydrological units. The impact of using watershed-constant or watershed-distributed SVAT parameters on the fluxes is analysed. The determination of watershed averaged evaporation with area-aggregated SVAT parameters is feasible without significant loss of accuracy. Distributed evaporation in heterogeneous watersheds, however, can be investigated only with remote sensing flux algorithms that can account for spatially variable air temperature, surface roughness, surface albedo and the stability correction of the temperature profile due to buoyancy. Erroneous results can be expected if area-aggregated SVAT parameters are used to calculate local evaporation. As most of the recently developed remote sensing flux algorithms are based on areal constant SVAT parameters, direct applications in watersheds are still limited. Copyright © 2001 John Wiley & Sons, Ltd. [source] Establishment of the 1st World Health Organization international standards for human papillomavirus type 16 DNA and type 18 DNAINTERNATIONAL JOURNAL OF CANCER, Issue 12 2010Dianna E. Wilkinson Abstract A World Health Organization collaborative study was conducted to evaluate candidate international standards for human papillomavirus (HPV) Type 16 DNA (NIBSC code 06/202) and HPV Type 18 DNA (NIBSC code 06/206) for use in the amplification and detection steps of nucleic acid-based assays. The freeze-dried candidate international standards were prepared from bulk preparations of cloned plasmid containing full-length HPV-16 or HPV-18 genomic DNA. Nineteen laboratories from 13 countries participated in the study using a variety of commercial and in-house quantitative and qualitative assays. The data presented here indicate that, upon freeze-drying, there is no significant loss in potency for the candidate HPV-18 DNA and a slight loss in potency for the candidate HPV-16 DNA; although this is likely not scientifically relevant when assay precision is considered. In general, the individual laboratory mean estimates for each study sample were grouped ±,2 log10 around the theoretical HPV DNA concentration of the reconstituted ampoule (1 × 107 HPV genome equivalents/mL). The agreement between laboratories is improved when potencies are made relative to the candidate international standards, demonstrating their utility in harmonizing amplification and detection steps of HPV-16 and ,18 DNA assays. Degradation studies indicate that the candidate international standards are extremely stable and suitable for long-term use. Based on these findings, the candidate standards were established as the 1st WHO international standards for HPV-16 DNA and HPV-18 DNA, each with a potency of 5 × 106 international units (IU) per ampoule or 1 × 107 IU mL,1 when reconstituted as directed. [source] New immunochemical fecal occult blood test with two-consecutive stool sample testing is a cost-effective approach for colon cancer screening: Results of a prospective multicenter study in Chinese patientsINTERNATIONAL JOURNAL OF CANCER, Issue 12 2006Shirong Li Abstract The purpose of the study is to evaluate a new immunochemical fecal occult blood test method (Hemosure IFOBT), and compare it to the Guaiac-based chemical method (CFOBT) for colorectal cancer detection. A hypothetical sequential method (SFOBT), in which IFOBT was used only as a confirmatory test for CFOBT, was also evaluated. A total of 324 patients were recruited from 5 major hospitals in Beijing, China. For each patient, 3 consecutive stool samples were collected for simultaneous CFOBT and IFOBT tests, followed by colonoscopic examination. We compared the sensitivity and specificity of the 3 methods (CFOBT, IFOBT and SFOBT) in two settings, with the first 2 consecutive samples versus all 3 samples. Although the sensitivity for the detection of cancer and large (>20 mm) or multiple adenoma was similar for all 3 methods in the three-sample setting, in the two-sample setting IFOBT had higher sensitivity than SFOBT for detecting cancer (87.8% vs. 75.5%, respectively, p < 0.05) and large (>20 mm) or multiple adenomas (65.4% vs. 42.3%, respectively, p < 0.05). The IFOBT also had a higher specificity than the CFOBT (89.2% vs. 75.5%, respectively, p < 0.01) in "normal" individuals defined by colonoscopy in the three-sample setting. Comparing two-sample setting to the three-sample setting, both CFOBT and SFOBT showed significant loss of sensitivity for the detection of cancer as well as adenoma, whereas the sensitivity for IFOBT did not change significantly. Overall, IFOBT with two-sample testing showed compatible sensitivity and specificity to the three-sample testing, and had a lower relative cost per cancer detected than the three-sample testing. In conclusion, the new Hemosure IFOBT with two consecutive stool samples appears to be the most cost-effective approach for colon cancer screening. © 2006 Wiley-Liss, Inc. [source] Enantioselective Aldol Reaction using Recyclable Montmorillonite-Entrapped N -(2-Thiophenesulfonyl)prolinamideADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2010Noriyuki Hara Abstract N -(2-Thiophenesulfonyl)prolinamide could be easily introduced into Montmorillonite by a simple ion-exchange reaction. The asymmetric aldol reactions between various isatins with acetone or acetaldehyde using a heterogeneous Montmorillonite-entrapped organocatalyst afforded products with high enantioselectivity. The catalyst was readily reusable without significant loss of catalytic activity or enantioselectivity. [source] Claisen,Schmidt Condensation Catalyzed by Metal-Organic FrameworksADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4 2010Amarajothi Dhakshinamoorthy Abstract Metal-organic framework [Fe(BTC) (BTC=1,3,5-benzenetricarboxylic acid)] is a convenient heterogeneous catalyst for the carbon-carbon bond forming reaction in toluene between acetophenone and benzaldehyde to give selectively chalcone in high yield. Fe(BTC) appears as a general catalyst able to synthesize selectively different chalcone derivatives bearing various functionalities. Fe(BTC) could be recycled with no significant loss of catalytic efficiency and crystallinity in subsequent runs. [source] Frequency reconfigurable RF circuits using photoconducting switchesINTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 1 2010D. Draskovic Abstract Designs for a frequency switchable dual-band branch-line coupler and a reconfigurable S-band power amplifier input matching network with photoconducting switches are presented. Frequency switching is achieved by increasing the power of the laser applied to the highly resistive silicon wafer and changing the properties of silicon under optical illumination. The advantages of this approach are high-speed switching, electromagnetic transparency (no interference), and thermal and electrical isolation between the device and the control circuit. A branch-line coupler frequency shift of 35% and 10% has been achieved from all switches off to all switches on in lower (900 MHz) and upper (1800 MHz) frequency bands, respectively. Frequency switchable class AB power amplifier with silicon switch in the input matching circuit has obtained the frequency tuning range of 2.5,3.5 GHz with no significant loss in efficiency and linearity. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010. [source] Imidazolium Ion-Tagged Proline Organocatalyst for ,-Aminoxylation of Aldehydes and Ketones in Ionic LiquidsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1 2010Xiong Ding Abstract A novel imidazolium ion-tagged L -proline catalyst has been developed. The asymmetric ,-aminoxylation of aldehydes and ketones with excellent enantioselectivities, up to 99% ee, and high yields in ionic liquids has been achieved. The system can be easily recycled and reused for at least six times without significant loss of yields and enantioselectivity. [source] Highly Enantioselective Epoxidation of Unfunctionalized Olefins Catalyzed by Chiral Jacobsen's Catalyst Immobilized on Phenoxy-Modified Zirconium Poly(syrene-phenylvinylphos- phonate)phosphateADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1 2010Xiaochuan Zou Abstract Chiral Jacobsen's catalyst was axially immobilized onto phenoxy-modified zirconium poly(styrene-phenylvinylphosphonate)phosphate (ZPS-PVPA). The immobilized catalysts show comparable ee values for asymmetric epoxidation of styrene and much higher ee values for ,-methylstyrene (73.7% vs. 54.0%) and indene (99.9% vs. 65.0%) than the homogeneous Jacobsen's catalyst. Moreover, the as-synthesized catalysts are relatively stable and can be recycled at least five times without significant loss of activity and enantioselectivity. A point worth emphasizing is that the heterogeneous catalysts afforded remarkable increases of conversion and ee values in the absence of expensive O-coordinating axial bases for the asymmetric epoxidation of olefins, especially for the epoxidation of ,-methylstyrene (conversion: from 24.3% to 99.9%; ee: from 29.4% to 73.7%), which may overcome the last obstacle for the potential industry application of chiral Jacobsen's catalyst. [source] Expanded Heterogeneous Suzuki,Miyaura Coupling Reactions of Aryl and Heteroaryl Chlorides under Mild ConditionsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 17 2009Dong-Hwan Lee Abstract A mesoporous LTA zeolite (MP-LTA)-supported palladium catalyst was developed for the highly efficient Suzuki,Miyaura reaction of aryl and heteroaryl chlorides. The couplings of various aryl chlorides with arylboronic acids in aqueous ethanol were efficiently achieved in the presence of 1.0,mol% of the catalyst. Furthermore, the scope of this catalyst was extended to the coupling of heteroaryl chlorides. Regardless of the substituents, all of the coupling reactions were very clean and highly efficient under mild heating. It shows that our catalyst is one of the most powerful heterogeneous catalysts for the coupling of a wide range of aryl and heteroaryl chlorides. The catalyst could be repetitively used at least 10 times without a significant loss of its catalytic activity. Compared to mesoporous SBA-15 and MCM-41 materials, the MP-LTA support proved to be very stable and robust to prevent degradation upon reuse. [source] Reusable Copper-Aluminum Hydrotalcite/rac -BINOL System for Room Temperature Selective Aerobic Oxidation of AlcoholsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 16 2009M. Lakshmi Kantam Abstract An efficient catalyst system consisting of copper-aluminum hydrotalcite/rac- BINOL ligand has been developed for the oxidation of alcohols using air as a green oxidant at room temperature. Various alcohols could be transformed into their corresponding aldehydes or ketones in good to excellent yields using the set of optimal conditions. This composite catalytic system can also be recovered and reused for several cycles without a significant loss of catalytic activity. [source] | ||||||||||||||||||||||||||||||||||||||||||||||