Home About us Contact
|
Home About us Contact | ||
|
|
||
Main Contributors (main + contributor)
Selected AbstractsBioaccumulation and trophic transfer of polychlorinated biphenyls by aquatic and terrestrial insects to tree swallows (Tachycineta bicolor)ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 4 2006Jonathan D. Maul Abstract Insectivorous passerines often bioaccumulate polychlorinated biphenyls (PCBs) via trophic transfer processes. Tree swallows (Tachycineta bicolor) frequently are used for estimating PCB bioaccumulation, yet the focus on specific trophic links between contaminated sediment and bird has been limited. Bioaccumulation of PCBs from sediment to tree swallows was examined with focus on trophic pathways by simultaneously examining PCBs in emergent aquatic and terrestrial insects and gut contents of nestlings. Total PCB concentrations increased from sediment (123.65 ± 15.93 ,g/kg) to tree swallow nestlings (2,827.76 ± 505.67 ,g/kg), with emergent aquatic insects, terrestrial insects, and gut content samples having intermediate concentrations. Biota-sediment accumulation factors (BSAFs) varied among congeners for tree swallow nestlings and for male and female Chironomus spp. For nestlings, the highest BSAF was for the mono- ortho -substituted congener 118. Nestling biomagnification values were similar for gut contents and female Chironomus spp., suggesting this diet item may be the main contributor to the overall PCB transfer to nestlings. However, gut content samples were highly variable and, on a PCB congener pattern basis, may have been influenced by other taxa, such as terrestrial insects. Considering dietary plasticity of many insectivorous birds, the present study suggests that a variety of potential food items should be considered when examining PCB accumulation in insectivorous passerines. [source] Highly Stable Au Nanoparticles with Tunable Spacing and Their Potential Application in Surface Plasmon Resonance BiosensorsADVANCED FUNCTIONAL MATERIALS, Issue 1 2010Shuyan Gao Abstract Colloidal Au-amplified surface plasmon resonance (SPR), like traditional SPR, is typically used to detect binding events on a thin noble metal film. The two major concerns in developing colloidal Au-amplified SPR lie in 1) the instability, manifested as a change in morphology following immersion in organic solvents and aqueous solutions, and 2) the uncontrollable interparticle distance, determining probe spacing and inducing steric hindrance between neighboring probe molecules. This may introduce uncertainties into such detecting techniques, degrade the sensitivity, and become the barricade hampering colloidal Au-based transducers from applications in sensing. In this paper, colloidal Au-amplified SPR transducers are produced by using ultrathin Au/Al2O3 nanocomposite films via a radio frequency magnetron co-sputtering method. Deposited Au/Al2O3 nanocomposite films exhibit superior stability, and average interparticle distances between Au nanoparticles with similar average sizes can be tuned by changing surface coverage. These characteristics are ascribed to the spacer function and rim confinement of dielectric Al2O3 and highlight their advantages for application in optimal nanoparticle-amplified SPR, especially when the probe size is smaller than the target molecule size. This importance is demonstrated here for the binding of protein (streptavidin) targets to the probe (biotin) surface. In this case, the dielectric matrix Al2O3 is a main contributor, behaving as a spacer, tuning the concentration of Au nanoparticles, and manipulating the average interparticle distance, and thus guaranteeing an appropriate number of biotin molecules and expected near-field coupling to obtain optimal sensing performance. [source] Intra- and extra-oral halitosis: finding of a new form of extra-oral blood-borne halitosis caused by dimethyl sulphideJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 9 2007Albert Tangerman Abstract Aim: The aim of this study was to unravel the origen and cause of intra-oral and extra-oral halitosis. Material and Methods: We studied 58 patients complaining of halitosis, using gas chromatography of volatile sulphur compounds (VSCs) in mouth and nose breath, organoleptic scoring of mouth and nose breath, Halimeter® readings of mouth air and tongue-coating inspection. Subjects had no precence or history of periodontitis. Result: Of 58 patients, 47 patients had halitosis of oral origin, six had halitosis of extra-oral origin and five had no halitosis (halitophobia). A strong correlation was found between the degree of intra-oral halitosis as measured by organoleptic scoring of mouth breath and the concentration of the VSCs hydrogen sulphide (H2S) and methyl mercaptan (CH3SH) in mouth breath. Taking into account the much larger odour index of CH3SH, it was concluded that CH3SH is the main contributor to intra-oral halitosis. In all six cases of extra-oral halitosis, halitosis was caused by the presence of elevated levels of dimethyl sulphide (CH3SCH3) in mouth and nose breath. Conclusion: Our study provides evidence that the VSC, CH3SH and to a lesser extent H2S are the main contributors to intra-oral halitosis and that CH3SCH3 is the main contributor to extra-oral or blood-borne halitosis, due to a hitherto unknown metabolic disorder. [source] Explaining the enhanced performance of pulsed bioreactors by mechanistic modelingAICHE JOURNAL, Issue 5 2008Amaya Franco Abstract In this work, steady-state mass balance based models were applied to two UASB reactors and three UAF for a better understanding of the role of pulsation on the efficacy improvement. Models were defined taking into account the hydraulic behavior of each digester and the limiting mechanism of the overall process kinetics (mass transfer or biochemical reaction rate). The application of the model allows to identify that mass transfer was the controlling step in all the reactors, except for the nonpulsed UASB, where methanogenic activity controlled the reactor performance in the last operation steady states. Mass transfer coefficients were higher for pulsed reactors and, in general, a good agreement between those estimated by an empirical correlation and from the model was obtained. Damköhler number values supported that the external mass transfer resistance was not negligible with respect to the process kinetic and in addition, in most cases, it controls the overall process in the reactors. The relative importance of external and internal mass transfer rate was calculated through the Biot number. The values of this dimensionless module indicated that external transport was the main contributor to overall mass transfer resistance. © 2008 American Institute of Chemical Engineers AIChE J, 2008 [source] Characteristics and outcome of unplanned extubation in ventilated preterm and term newborns on a neonatal intensive care unitPEDIATRIC ANESTHESIA, Issue 9 2006ALEX VELDMAN MD Summary Background :,Unplanned extubation events (UEE) are a serious hazard to patient safety, especially on a neonatal intensive care unit (NICU), where reestablishing a secure airway can be difficult. The following study was undertaken to analyze characteristics of UEE and develop prevention strategies. Methods :,A retrospective cohort study on a level III single center NICU was undertaken. Patient records of a 12-month period from December 2003 to December 2004 were analyzed using a standardized evaluation form. Fischer's exact t -test and the Mann,Whitney U -Ranked Sum test were used for statistical analysis. Results :,One hundred and four neonates with a total ventilation time of 14 495 h were included in this study. Of these patients 12 UEE were observed (1 UEE/1208 h of ventilation time). Neither median birth weight [1445 g (range 460,4650) vs 1755 g (range 460,3570 g)] nor median gestational age [31.5 weeks (range 25.6,39.6 weeks) vs 32.7 weeks (range 23.9,41.5 weeks)] differed significantly between neonates with UEE compared with the total group. When the UEE occurred, the neonates were cared for by experienced nursing staff with a median of 10 years nursing experience. The workload for the individual nurse was high: during shifts when UEE happened, each nurse had to take care of 3.85 patients (range 1.8,5 patients). This workload was higher than the average of 3 (range 1.6,6) patients/nurse during the study period. The most frequently reported reason for UEE was difficult fixation of the tracheal tube (TT) (four patients), followed by handling of the infant by nursing staff or physiotherapy (two patients) or an active infant in whom dislocation of the TT occurred without external manipulations (three patients). In three instances, the reason for the UEE was not documented. Of the 12 UEE observed in 10 patients, three required immediate reintubation, five were managed with nasal continuous positive airway pressure and four did not require further respiratory support. Of those who required support, FiO2 increased by 14% over baseline compared with the FiO2 prior to UEE. Conclusions :,Inadequate TT fixation could be identified as the main contributor to UEE and should be targeted in prevention strategies. The reintubation rate after UEE was only 25%. Overall, UEE did not result in an adverse outcome in terms of mortality. Length of stay on NICU was significantly longer in UEE patients. [source] Contribution of wood fiber hygroexpansion to moisture induced thickness swelling of composite platesPOLYMER COMPOSITES, Issue 5 2010Karin M. Almgren One of the main drawbacks of wood fiber-based composite materials is their propensity to swell due to moisture uptake. Because the wood fibers are usually the main contributor to hygroexpansion, it is of interest to quantify the hygroexpansion coefficient of wood fibers, to compare and rank different types of fibers. This investigation outlines an inverse method to estimate the transverse hygroexpansion coefficient of wood fibers based on measurements of moisture induced thickness swelling of composite plates. The model is based on composite micromechanics and laminate theory. Thickness swelling has been measured on polylactide matrix composites with either bleached reference fibers or crosslinked fibers. The crosslinking modification reduced the transverse hygroexpansion of the composites and the transverse coefficient of hygroexpansion of the fibers was reduced from 0.28 strain per relative humidity for reference fibers to 0.12 for cross-linked fibers. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers [source] Efficiency and Program-Contract Bargaining in Spanish Public HospitalsANNALS OF PUBLIC AND COOPERATIVE ECONOMICS, Issue 4 2004Juan Ventura The results demonstrate that a significant improvement has occurred. The decomposition of the Malmquist productivity index shows that efficiency change has been the main contributor to productivity improvement. We also analyse the dynamic implications of program-contract bargaining. In particular, the data support the hypothesis that the bargaining process has been subject to a ratchet effect, i.e., the more a hospital does today, the more the hospital is asked to do in the future. This result threatens the credibility of the program-contract as an incentive system. [source] Effect of feeding rate on fatty acid composition of sharpsnout seabream (Diplodus puntazzo)AQUACULTURE NUTRITION, Issue 5 2004M. Rondán Abstract The effects of different feeding rates on the lipids fatty acid profile of sharpsnout seabream (Diplodus puntazzo) tissues were studied. During a 15-day period, four fish groups were allowed to feed to satiation, at two-thirds and one-third of satiety, and starved, respectively. Reducing food intake progressively increased the n-3:n-6 relationship by increase of n-3 (mainly Highly Unsaturated Fatty Acids) and decrease of n-6 fatty acid percentages. In perivisceral fat, this n-3:n-6 value was already statistically significant lower for the group fed to satiety (1.29 versus 1.71, 1.80 and 1.65 for the two-third-fed, one-third-fed and fasted groups, respectively), whereas in the white muscle (1.69 versus 2.13 and 2.12) and liver (0.83 versus 1.40 and 2.66) the differences were statistically significant only for the one-third-fed and fasted groups. Linoleic acid was the main contributor to the n-6 drop, whereas the n-3 fatty acids preferentially preserved were for the most part essential fatty acids. Fat quality indices (thrombogenic and atherogenic) were not affected by food restriction except for liver, being the former significantly lower in the one-third-fed and fasted groups. Food intake restriction to one-third of satiety levels was enough to trigger the mechanisms that preserve essential fatty acids. [source] Comparison of enzymes involved in sugar metabolism from Shang-24 (Vinifera quinguangularis) and Cabernet Sauvignon (Vinifera vinifera) at veraisonAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 1 2009Q.-H. PAN Abstract Background and Aims:, Sugar is a main contributor to the quality of grape berries, but little is known about the characteristics of sugar metabolism in Chinese wild grapes. Here, enzymes related to sugar metabolism were investigated in berries of both Shang-24 (Vitis quinguangularis Rehd), a wild grape native to China, and Cabernet Sauvignon (V. vinifera L.). Methods and Results:, Analyses using high performance liquid chromatography and spectrophotometer showed that Shang-24 contained lower levels of glucose and fructose, compared with Cabernet Sauvignon, but had higher activities of enzymes related to sugar hydrolysis, particularly soluble acid invertase (SAI) and ,-amylase. Analyses of enzyme kinetics, enzyme-linked immunosorbent assay and Western blot revealed that SAI and ,-amylase in Shang-24 had low Km values and that high levels of both enzymes were present. Furthermore, a novel peptide of SAI of 105 kDa was detected in Shang-24 along with a peptide of 60 kDa that also was present in Cabernet Sauvignon. Conclusions:, It is thus suggested that biochemical characteristics of SAI and ,-amylase in Shang-24 differ from those in Cabernet Sauvignon, and the novel peptide may be related to high activity of SAI in Shang-24. Significance of the Study:, These data provide an essential basis for further study of the genetic regulation of sugar and its metabolism in grape berries. [source] Techno-economic evaluation of a two-step biological process for hydrogen productionBIOTECHNOLOGY PROGRESS, Issue 2 2010Mattias Ljunggren Abstract An integrated biological process for the production of hydrogen based on thermophilic and photo-heterotrophic fermentation was evaluated from a technical and economic standpoint. Besides the two fermentation steps the process also includes pretreatment of the raw material (potato steam peels) and purification of hydrogen using amine absorption. The study aimed neither at determining the absolute cost of biohydrogen nor at an economic optimization of the production process, but rather at studying the effects of different parameters on the production costs of biohydrogen as a guideline for future improvements. The effect of the key parameters, hydrogen productivity and yield and substrate concentration in the two fermentations on the cost of the hydrogen produced was studied. The selection of the process conditions was based mainly on laboratory data. The process was simulated by use of the software Aspen Plus and the capital costs were estimated using the program Aspen Icarus Process Evaluator. The study shows that the photo-fermentation is the main contributor to the hydrogen production cost mainly because of the cost of plastic tubing, for the photo-fermentors, which represents 40.5% of the hydrogen production cost. The costs of the capital investment and chemicals were also notable contributors to the hydrogen production cost. Major economic improvements could be achieved by increasing the productivity of the two fermentation steps on a medium-term to long-term scale. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source] Aquifer interactions with a polluted mountain river of NicaraguaHYDROLOGICAL PROCESSES, Issue 13 2008Jose Alfredo Mendoza Abstract The interactions between a stream and nearby shallow aquifers were investigated in a mountain basin being polluted by mercury released during mining in central Nicaragua. Hourly data series of water levels and temperatures were analysed using cross-correlation. Resistivity imaging was used to map the subsurface and to complement the hydrological data interpretation. The results show the complex hydrogeological conditions that characterize the region, with weathering and fractured rock as main contributors to groundwater transport. The resistivity images suggest the presence of two vertical dykes perpendicular to the stream, and zones rich in clay. The data series indicate a rapid response from the aquifers to recharge events, followed by immediate discharge on a yearly basis. Furthermore, alternating periods of stream infiltration and aquifer discharge were identified. This work demonstrates that surface water pollution is a threat to groundwater quality in the area. Copyright © 2007 John Wiley & Sons, Ltd. [source] Evidence for the accelerations of sea level on multi-decade and century timescalesINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 6 2009P. L. Woodworth Abstract A modification in the rate of change of sea level (i.e. an ,acceleration' or ,nonlinear trend') is an important climate-related signal, which requires confirmation and explanation. In this study, the evidence for accelerations in regional and global average sea level on timescales of several decades and longer is reviewed by inter-comparison of the recent findings of different researchers and by inspection of original tide gauge records. Most sea-level data originate from Europe and North America, and both the sets display evidence for a positive acceleration, or ,inflexion', around 1920,1930 and a negative one around 1960. These inflexions are the main contributors to reported accelerations since the late 19th century, and to decelerations during the mid- to late 20th century. However, these characteristic features are not always found in records from other parts of the world. Although some aspects of the sea-level time series are consistent with changes in rates of globally averaged temperature changes, volcanic eruptions and natural climate variability, modelling undertaken so far has been unable to describe these features adequately. This emphasizes the need for a major enhancement of the sea-level data set, especially for those parts of the world without long tide gauge records, in order to obtain greater insight into the spatial dependence of accelerations. A number of complementary methods must be employed, of which salt marsh techniques offer the possibility of obtaining time series similar to those that would have been obtained from coastal tide gauges. Copyright © 2008 Royal Meteorological Society [source] Intra- and extra-oral halitosis: finding of a new form of extra-oral blood-borne halitosis caused by dimethyl sulphideJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 9 2007Albert Tangerman Abstract Aim: The aim of this study was to unravel the origen and cause of intra-oral and extra-oral halitosis. Material and Methods: We studied 58 patients complaining of halitosis, using gas chromatography of volatile sulphur compounds (VSCs) in mouth and nose breath, organoleptic scoring of mouth and nose breath, Halimeter® readings of mouth air and tongue-coating inspection. Subjects had no precence or history of periodontitis. Result: Of 58 patients, 47 patients had halitosis of oral origin, six had halitosis of extra-oral origin and five had no halitosis (halitophobia). A strong correlation was found between the degree of intra-oral halitosis as measured by organoleptic scoring of mouth breath and the concentration of the VSCs hydrogen sulphide (H2S) and methyl mercaptan (CH3SH) in mouth breath. Taking into account the much larger odour index of CH3SH, it was concluded that CH3SH is the main contributor to intra-oral halitosis. In all six cases of extra-oral halitosis, halitosis was caused by the presence of elevated levels of dimethyl sulphide (CH3SCH3) in mouth and nose breath. Conclusion: Our study provides evidence that the VSC, CH3SH and to a lesser extent H2S are the main contributors to intra-oral halitosis and that CH3SCH3 is the main contributor to extra-oral or blood-borne halitosis, due to a hitherto unknown metabolic disorder. [source] Metabolomics-based systematic prediction of yeast lifespan and its application for semi-rational screening of ageing-related mutantsAGING CELL, Issue 4 2010Ryo Yoshida Summary Metabolomics , the comprehensive analysis of metabolites , was recently used to classify yeast mutants with no overt phenotype using raw data as metabolic fingerprints or footprints. In this study, we demonstrate the estimation of a complicated phenotype, longevity, and semi-rational screening for relevant mutants using metabolic profiles as strain-specific fingerprints. The fingerprints used in our experiments are profiled data consisting of individually identified and quantified metabolites rather than raw spectrum data. We chose yeast replicative lifespan as a model phenotype. Several yeast mutants that affect lifespan were selected for analysis, and they were subjected to metabolic profiling using mass spectrometry. Fingerprinting based on the profiles revealed a correlation between lifespan and metabolic profile. Amino acids and nucleotide derivatives were the main contributors to this correlation. Furthermore, we established a multivariate model to predict lifespan from a metabolic profile. The model facilitated the identification of putative longevity mutants. This work represents a novel approach to evaluate and screen complicated and quantitative phenotype by means of metabolomics. [source] DETERMINATION OF HISTAMINE AND BACTERIAL ISOLATION IN MARLIN FILLETS (MAKAIRA NIGRICANS) IMPLICATED IN A FOODBORNE POISONINGJOURNAL OF FOOD SAFETY, Issue 3 2010H.C. CHEN ABSTRACT An incident of foodborne poisoning causing illness in seven victims due to ingestion of marlin fillets occurred in August, 2008, in Kaohsiung City, southern Taiwan. The two suspected marlin samples contained 47.8 and 43.5 mg/100 g of histamine, which is greater than the 5.0 mg/100 g allowable limit suggested by the U.S. Food and Drug Administration. Given the allergy-like symptoms of the victims and the high histamine content in the suspected marlin samples, this foodborne poisoning was strongly suspected to be due to histamine intoxication. Two histamine-producing bacterial strains capable of producing 3.10 ppm and 4.20 ppm of histamine in trypticase soy broth (TSB) supplemented with 1.0% l -histidine (TSBH) were identified as Bacillus subtilis by 16S rDNA sequencing with polymerase chain reaction amplification. However, major histamine-forming bacteria might have been killed during the preparation of fillets before serving and these two B. subtilis isolates might not be the main contributors to histamine accumulation in suspected fillets. PRACTICAL APPLICATIONS Based on the finding that high contents of histamine (>40 mg/100 g) were detected in the suspected marlin samples, we speculate the temperature abuse of the fillets before cooking contributed to the presence of high histamine levels in marlin fillets and resulted in foodborne poisoning. Although two histamine-producing Bacillus subtilis strains were isolated from suspected fish samples, both might not to be the main contributors to histamine accumulation because of low histamine production. These results re-emphasize proper handling temperature for seafoods and offer an important awareness which Makaira nigricans fillets could become a hazardous food item in causing histamine poisoning even though no quality deficiency was observed on the fillets. [source] Antioxidant Activity of Crude Extract, Alkaloid Fraction, and Flavonoid Fraction from Boldo (Peumus boldus Molina) LeavesJOURNAL OF FOOD SCIENCE, Issue 5 2004N. Quezada ABSTRACT: Boldo is an endemic plant from Chile widely used in folk medicine, whose biological (mainly antioxidant) activity has been attributed to the presence of the alkaloid boldine. The aim of this study was to determine the contribution of the flavonoid and other crude fractions from boldo leaves to the antioxidant activity of extracts. The main constituent in the flavonoid fraction was also isolated. The antioxidant activity and reducing power of crude boldo extract and fractions were measured and compared with natural and synthetic antioxidants. The antioxidant activity of boldo leaf extracts came mainly from the flavonoid fraction (44.1%) followed by the alkaloid fraction (15.6%), with catechin and boldine being the main contributors of the antioxidant activity of these 2 fractions (60.9% and 35.6% of the total activity, respectively). On the basis of these results, we propose to use catechin and boldine as markers for the antioxidant activity of boldo leaves. Tailor-made antioxidants to be used in foods can be prepared by enriching these 2 fractions. [source] Genetic fate mapping of Olig2 progenitors in the injured adult cerebral cortex reveals preferential differentiation into astrocytesJOURNAL OF NEUROSCIENCE RESEARCH, Issue 16 2008Kouko Tatsumi Abstract Olig2 is a basic helix-loop-helix (bHLH) transcription factor essential for development of motoneurons and oligodendrocytes. It is known that Olig2+ cells persist in the central nervous system (CNS) from embryonic to adult stages and that the number of Olig2+ progenitors increases in the injured adult CNS. Recent studies have demonstrated an inhibitory action of Olig2 on neurogenesis in adult CNS, but the fate of Olig2+ cells in the injured state remains largely unknown. To trace directly the fate of Olig2 cells in the adult cerebral cortex after injury, we employed the CreER/loxP system to target the olig2 locus. In this genetic tracing study, green fluorescent protein (GFP) reporter-positive cells labeled after cryoinjury coexpressed glial fibrillary acidic protein (GFAP), an astrocytic marker. Electron microscopy also showed that GFP+ cells have the ultrastructural characteristics of astrocytes. Furthermore, GFP+ cells labeled before injury, most of which had been NG2 cells, also produced bushy astrocytes. Here we show direct evidence that Olig2+ cells preferentially differentiate into astrocytes, which strongly express GFAP, in response to injury in the adult cerebral cortex. These results suggest that reactive astrocytes, known to be the main contributors to glial scars, originate, at least in part, from Olig2+ cells. © 2008 Wiley-Liss, Inc. [source] Biotic diachroneity during the Ordovician Radiation: evidence from South ChinaLETHAIA, Issue 3 2006Renbin Zhan The Ordovician radiation was one of the most marked and sustained increases in Phanerozoic biodiversification; nevertheless it occurred against a background of minimal global climatic and environmental perturbations. Detailed investigations of the Ordovician successions on the Yangtze Platform of the South China palaeoplate indicate that: (1) the brachiopod ,- and ,-diversity changes are diachronous; (2) macroevolutionary patterns were different across the South China palaeoplate, with the Early Ordovician brachiopod radiation first occurring in normal marine, shallow-water environments and then moving gradually to both nearer-shore and offshore locations; (3) the main contributors to the initial Ordovician brachiopod radiation were the Orthida and Pentamerida; the typical Ordovician brachiopod fauna, dominated by the Orthida and Strophomenida, did not appear until the late Mid Ordovician (Undulograptus austrodentatus Biozone) when the Strophomenida apparently replaced the dominant position of the Pentamerida within the fauna; (4) different ecotypes (e.g., sessile benthos, mobile benthos together with pelagic and planktonic organisms) demonstrate substantially different macroevolutionary patterns. The Ordovician brachiopod radiation of South China was apparently earlier than that suggested by global trends together with the data available from other palaeoplates or terranes, which may be related to its unique palaeogeographic position (peri-Gondwanan terrane gradually moving to equatorial latitudes). [source] Glial reactions in Parkinson's diseaseMOVEMENT DISORDERS, Issue 4 2008Patrick L. McGeer MD Abstract Dopaminergic neurons of the substantia nigra are particularly vulnerable to oxidative and inflammatory attack. Such processes may play a crucial role in the etiology of Parkinson disease (PD). Since glia are the main generators of these processes, the possibility that PD may be caused by glial dysfunction needs to be considered. This review concentrates on glial reactions in PD. Reactive astrocytes and reactive microglia are abundant in the substantia nigra (SN) of PD cases indicating a robust inflammatory state. Glia normally serve neuroprotective roles but, given adverse stimulation, they may contribute to damaging chronic inflammation. Microglia, the phagocytes of brain, may be the main contributors since they can produce large numbers of superoxide anions and other neurotoxins. Their toxicity towards dopaminergic neurons has been demonstrated in tissue culture and various animal models of PD. The MPTP and ,-synuclein models are of particular interest. Years after exposure to MPTP, inflammation has been observed in the SN. This has established that an acute insult to the SN can result in a sustained local inflammation. The ,-synuclein model indicates that an endogenous protein can induce inflammation, and, when overexpressed, can lead to autosomal dominant PD. Less is known about the role of astrocytes than microglia, but they are known to secrete both inflammatory and anti-inflammatory molecules and may play a role in modulating microglial activity. Oligodendrocytes do not seem to play a role in promoting inflammation although, like neurons, they may be damaged by inflammatory processes. Further research concerning glial reactions in PD may lead to disease-modifying therapeutic approaches. © 2007 Movement Disorder Society [source] Diversity of mtDNA lineages in Portugal: not a genetic edge of European variationANNALS OF HUMAN GENETICS, Issue 6 2000L. PEREIRA The analysis of the hypervariable regions I and II of mitochondrial DNA in Portugal showed that this Iberian population presents a higher level of diversity than some neighbouring populations. The classification of the different sequences into haplogroups revealed the presence of all the most important European haplogroups, including those that expanded through Europe in the Palaeolithic, and those whose expansion has occurred during the Neolithic. Additionally a rather distinct African influence was detected in this Portuguese survey, as signalled by the distributions of haplogroups U6 and L, present at higher frequencies than those usually reported in Iberian populations. The geographical distributions of both haplogroups were quite different, with U6 being restricted to North Portugal whereas L was widespread all over the country. This seems to point to different population movements as the main contributors for the two haplogroup introductions. We hypothesise that the recent Black African slave trade could have been the mediator of most of the L sequence inputs, while the population movement associated with the Muslim rule of Iberia has predominantly introduced U6 lineages. [source] The Equilibrium Yen,Dollar Rate: 1976,91ASIAN ECONOMIC JOURNAL, Issue 1 2002Anthony De Carvalho This paper presents a definition of the equilibrium exchange rate that is based on a modified version of purchasing power parity (PPP) for traded goods. Employing constant elasticity of substitution (CES) production functions and data from 28 three-digit international standard industrial classification (ISIC) manufacturing industries, the equilibrium Yen-Dollar rate is calculated for the period between 1976 and 1991 (a time in which the Yen appreciated markedly against the Dollar) showing that the actual Yen-Dollar rate closely tracked the equilibrium rate over that time. The results suggest that strong growth in Japanese labor productivity, coupled with Japan's relatively low capital-labor elasticity of sub-stitution, were the main contributors to the Yen's long-run appreciation. [source] Optical and near-infrared observations of hard serendipitous Chandra sourcesASTRONOMISCHE NACHRICHTEN, Issue 1-2 2003C.S. Crawford Abstract We have been carrying out a successful observational programme targeted at finding the highly obscured quasars that are thought to be the main contributors to the hard X-ray background. Out of 56 sources so far studied with optical and near-infrared imaging and spectroscopy, we have found three definite and a further twelve possible Type II quasars. Few sources show significant line emission, suggesting that the line photons are depleted by the large columns of obscuring matter. The redshift distribution of our sources shows a distinct peak at z , 1. The broad-band colours and magnitudes of the optical/near-infrared counterparts indicate that the light in these bands is dominated by the continuum of a massive bright galaxy. [source] Trends and determinants of caesarean sections births in Queensland, 1997,2006AUSTRALIAN AND NEW ZEALAND JOURNAL OF OBSTETRICS AND GYNAECOLOGY, Issue 6 2009Stuart HOWELL Background:, The determinants of Queensland's rising caesarean section (CS) rate remain poorly understood because of the historical absence of standard classification methods. Aims:, We applied the Robson Ten Group Classification System (RTGCS) to population-based data to identify the main contributors to Queensland's rising CS rate. Method:, The RTGCS was applied retrospectively to the Queensland Perinatal Data Collection. CS rates were described for all ten RTGCS groups using data from 2006. Trends were evaluated using data for the years 1997,2006. Public and private sector patients were evaluated separately. Results:, In Queensland, in 2006, CS rates were 26.9 and 48.0% among public and private sector patients, respectively. Multiparous women with a previous caesarean birth (Group 5) made the greatest contribution to the CS rate in both sectors, followed by nulliparous women who had labour induced or were delivered by CS prior to the onset of labour (Group 2) and nulliparous women in spontaneous labour (Group 1). CS rates have risen in all RTGCS groups between 1997 and 2006. The trend was pronounced among multiparous women with a previous caesarean delivery (Group 5), among women with multiple pregnancies (Group 8) and among nulliparous women who had labour induced or were delivered by CS prior to the onset of labour (Group 2). Conclusions:, The CS rate in Queensland in 2006 was higher than in any other Australian state. The increase in Queensland's CS rates can be attributed to both the rising number of primary caesarean births and the rising number of repeat caesareans. [source] A new way of looking at Caesarean section birthsAUSTRALIAN AND NEW ZEALAND JOURNAL OF OBSTETRICS AND GYNAECOLOGY, Issue 4 2007Fergus P. McCARTHY Abstract Aims:, To implement the Robson Ten Group Classification System (TGCS) at the Royal Women's Hospital (RWH), Melbourne, in order to determine the main contributors to the rising Caesarean section (CS) rate. Methods:, The TGCS divides women into ten groups according to parity, past obstetric history, singleton or multiple pregnancy, fetal presentation, gestational age and mode of onset of labour/delivery. The TGCS was applied retrospectively to the population of women who had a registered birth at the RWH between January 2005 and 31 December 2005. Results:, A total of 5833 women gave birth to 6011 babies during the study period. A total of 1651 women (28.3%) had a CS birth. The total CS rates ranged from 3.7% (group 3) to 100% (group 9). Women in groups 1 and 2 were the greatest contributors to the emergency CS rate, 4.2% and 4.9%, respectively. Women in group 5 were the single greatest contributor to both the elective CS rate and the total CS rate. Conclusions:, The TGCS was successfully implemented at the RWH in 2005. The TGCS is ongoing, enabling monitoring of CS rates. The Robson TGCS demonstrates the need to focus on the care of women in groups 1, 2 and 5 in particular, if CS rates are to be reduced. [source] Partition of thermodynamic energies of drug,DNA complexationBIOPOLYMERS, Issue 9 2009V. V. Kostjukov Abstract We report a computation methodology, which leads to the ability to partition the Gibb's free energy for the complexation reaction of aromatic drug molecules with DNA. Using this approach, it is now possible to calculate the absolute values of the energy contributions of various physical factors to the DNA binding process, whose summation gives a value that is reasonably close to the experimentally measured Gibb's free energy of binding. Application of the methodology to binding of various aromatic drugs with DNA provides an answer to the question "What forces are the main contributors to the stabilization of aromatic ligand,DNA complexes?" © 2009 Wiley Periodicals, Inc. Biopolymers 91: 773,790, 2009. This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source] | ||||||||||||||||||||||||||||