Home About us Contact
|
Home About us Contact | ||
|
|
||
Distinct Characteristics (distinct + characteristic)
Selected AbstractsWidespread capacity to metabolize polychlorinated biphenyls by diverse microbial communities in soils with no significant exposure to PCB contaminationENVIRONMENTAL MICROBIOLOGY, Issue 8 2007Alexandre J. Macedo Summary The purpose of this work was to determine the extent of microbial metabolic potential for polychlorinated biphenyls (PCBs) in soils that have had no previous exposure to this class of xenobiotic pollutants. Soil and sediment samples of distinct characteristics from six sites in Germany were used to inoculate PCB oil (Aroclor 1242) microdroplets. All samples yielded multispecies biofilms, as revealed by single-strand conformation polymorphism (SSCP) analyses of polymerase chain reaction (PCR) analysis of 16S rRNA genes, and sequence analysis of the main amplicons. Microbes representing 20 different operational taxonomic units (OTUs) were identified in the biofilms, but only a few were common to all biofilms, namely those closely related to Aquabacterium sp., Caulobacter sp., Imtechium assamiensis, Nevskia ramosa, Parvibaculum lavamentivorans and Burkholderia sp. The PCB biofilm communities were always distinct from control biofilms developing from the same samples in the absence of PCB. All PCB droplet-grown biofilms degraded multiple PCB congeners but differed in the congener spectra they degraded. These findings reveal that microbial potential to degrade PCBs is widespread in soils that have not been subjected to PCB contamination, and that this potential is characteristic of consortia of very diverse phylogenetic composition. [source] Involvement of astroglial ceramide in palmitic acid-induced Alzheimer-like changes in primary neuronsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2007Sachin Patil Abstract A high-fat diet has been shown to significantly increase the risk of the development of Alzheimer's disease (AD), a neurodegenerative disease histochemically characterized by the accumulation of amyloid beta (A,) protein in senile plaques and hyperphosphorylated tau in neurofibrillary tangles. Previously, we have shown that saturated free fatty acids (FFAs), palmitic and stearic acids, caused increased amyloidogenesis and tau hyperphosphorylaion in primary rat cortical neurons. These FFA-induced effects observed in neurons were found to be mediated by astroglial FFA metabolism. Therefore, in the present study we investigated the basic mechanism relating astroglial FFA metabolism and AD-like changes observed in neurons. We found that palmitic acid significantly increased de-novo synthesis of ceramide in astroglia, which in turn was involved in inducing both increased production of the A, protein and hyperphosphorylation of the tau protein. Increased amyloidogenesis and hyperphoshorylation of tau lead to formation of the two most important pathophysiological characteristics associated with AD, A, or senile plaques and neurofibrillary tangles, respectively. In addition to these pathophysiological changes, AD is also characterized by certain metabolic changes; abnormal cerebral glucose metabolism is one of the distinct characteristics of AD. In this context, we found that palmitic acid significantly decreased the levels of astroglial glucose transporter (GLUT1) and down-regulated glucose uptake and lactate release by astroglia. Our present data establish an underlying mechanism by which saturated fatty acids induce AD-associated pathophysiological as well as metabolic changes, placing ,astroglial fatty acid metabolism' at the center of the pathogenic cascade in AD. [source] Identification of three dominant rainfall regions within Indonesia and their relationship to sea surface temperatureINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 12 2003Edvin Aldrian Abstract The characteristics of climatic rainfall variability in Indonesia are investigated using a double correlation method. The results are compared with empirical orthogonal function (EOF) and rotated EOF methods. In addition, local and remote responses to sea-surface temperature (SST) are discussed. The results suggest three climatic regions in Indonesia with their distinct characteristics. Region A is located in southern Indonesia from south Sumatera to Timor island, southern Kalimantan, Sulawesi and part of Irian Jaya. Region B is located in northwest Indonesia from northern Sumatra to northwestern Kalimantan. Region C encompasses Maluku and northern Sulawesi. All three regions show both strong annual and, except Region A, semi-annual variability. Region C shows the strongest El Niño,southern oscillation (ENSO) influence, followed by Region A. In Region B, the ENSO-related signal is suppressed. Except for Region B, there are significant correlations between SST and the rainfall variabilities, indicating a strong possibility for seasonal climate predictions. March to May is the most difficult season to predict the rainfall variability. From June to November, there are significant responses of the rainfall pattern to ENSO in Regions A and C. A strong ENSO influence during this normally dry season (June to September) is hazardous in El Niño years, because the negative response means that higher SST in the NIÑO3 of the Pacific region will lower the rainfall amount over the Indonesian region. Analyses of Indonesian rainfall variability reveal some sensitivities to SST variabilities in adjacent parts of the Indian and Pacific Oceans. Copyright © 2003 Royal Meteorological Society [source] Adaptive directional-aware location update strategyINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 2 2004Tracy Tung Abstract In this paper, a new tracking strategy, the directivity-aware location updating scheme was developed to better utilize the distinct characteristics of individual users on travelling directions. In this new adaptive scheme, an optimal distance-based update threshold is selected according to the call-to-mobility ratio and a transitional directivity index, introduced to give indications of the mobile's travelling patterns. It is found that as far as mobility characteristics are concerned, the actual transitional direction of roaming mobiles plays a significant role in selecting the optimal threshold in addition to the usual perception about mobility rate. Its advantage becomes even more visible when an optimal threshold is not theoretically obtainable due to certain restrictions imposed by the network during times of high system loadings. Simulation results show that the additional information made available about roaming mobile's transitional directivity is critical to ensure that the best available sub-optimal threshold is realizable. Other advances in this paper include the simplification of existing Markovian movement model. With the improved model presentation, the number of states necessary to simulate such memoryless movements is reduced. Consequently, the computational complexity involved is also lessened. Copyright © 2004 John Wiley & Sons, Ltd. [source] The protein family of glucose transport facilitators: It's not only about glucose after allIUBMB LIFE, Issue 5 2010Robert Augustin Abstract The protein family of facilitative glucose transporters comprises 14 isoforms that share common structural features such as 12 transmembrane domains, N- and C-termini facing the cytoplasm of the cell, and a N-glycosylation side either within the first or fifth extracellular loop. Based on their sequence homology, three classes can be distinguished: class I includes GLUT1-4 and GLUT14, class II the "odd transporters" GLUT5, 7, 9, 11, and class III the "even transporters" GLUT6, 8, 10, 12 and the proton driven myoinositol transporter HMIT (or GLUT13). With the cloning and characterization of the more recent class II and III isoforms, it became apparent that despite their structural similarities, the different isoforms not only show a distinct tissue-specific expression pattern but also show distinct characteristics such as alternative splicing, specific (sub)cellular localization, and affinities for a spectrum of substrates. This review summarizes the current understanding of the physiological role for the various transport facilitators based on human genetically inherited disorders or single-nucleotide polymorphisms and knockout mice models. The emphasis of the review will be on the potential functional role of the more recent isoforms. © 2010 IUBMB IUBMB Life, 62(5): 315,333, 2010 [source] Direct and indirect bully-victims: differential psychosocial risk factors associated with adolescents involved in bullying and victimizationAGGRESSIVE BEHAVIOR, Issue 6 2006Zopito A. Marini Abstract The present study examined psychosocial risk factors that differentiated direct and indirect bully-victims from bullies, victims and uninvolved adolescents. A total of 7,290 (3,756 girls) students (ages 13,18,yr) from a region of Southern Ontario, Canada, completed a number of self-report measures to determine the relation between direct and indirect bullying and victimization and several psychosocial risk factors, including normative beliefs about antisocial acts, angry-externalizing coping, social anxiety, depression, self-esteem, temperament, attachment, parental monitoring and peer relational problems. ANCOVA and logistic regression analyses indicated that indirect bully-victims and victims were similar in demonstrating greater internalizing problems and peer relational problems than indirect bullies and uninvolved participants. Furthermore, adolescents involved in indirect bullying (bullies, bully-victims) reported a higher level of normative beliefs legitimizing antisocial behaviour and less parental monitoring (males only) than indirect victims and uninvolved participants. Only normative beliefs legitimizing antisocial behaviour distinguished direct bully-victims and bullies from victims and uninvolved adolescents. Results illuminate the distinct characteristics of direct and indirect bully-victims; theoretical and clinical implications are discussed. Aggr. Behav. 32:551,569. 2006. © 2006 Wiley-Liss, Inc. [source] Relationships between soil hydrology and forest structure and composition in the southern Brazilian AmazonJOURNAL OF VEGETATION SCIENCE, Issue 2 2007Stefan Jirka Abstract Question: Is soil hydrology an important niche-based driver of biodiversity in tropical forests? More specifically, we asked whether seasonal dynamics in soil water regime contributed to vegetation partitioning into distinct forest types. Location: Tropical rain forest in northwestern Mato Grosso, Brazil. Methods: We investigated the distribution of trees and lianas , 1 cm DBH in ten transects that crossed distinct hydrological transitions. Soil water content and depth to water table were measured regularly over a 13-month period. Results: A detrended correspondence analysis (DCA) of 20 dominant species and structural attributes in 10 × 10 m subplots segregated three major forest types: (1) high-statured upland forest with intermediate stem density, (2) medium-statured forest dominated by palms, and (3) low-statured campinarana forest with high stem density. During the rainy season and transition into the dry season, distinct characteristics of the soil water regime (i.e. hydro-indicators) were closely associated with each vegetation community. Stand structural attributes and hydro-indicators were statistically different among forest types. Conclusions: Some upland species appeared intolerant of anaerobic conditions as they were not present in palm and campinarana sites, which experienced prolonged periods of saturation at the soil surface. A shallow impermeable layer restricted rooting depth in the campinarana community, which could heighten drought stress during the dry season. The only vegetation able to persist in campinarana sites were short-statured trees that appear to be well-adapted to the dual extremes of inundation and drought. [source] HAG2/MYB76 and HAG3/MYB29 exert a specific and coordinated control on the regulation of aliphatic glucosinolate biosynthesis in Arabidopsis thalianaNEW PHYTOLOGIST, Issue 3 2008Tamara Gigolashvili Summary ,,In a previous transactivation screen, two Arabidopsis thaliana R2R3-MYB transcription factors, HAG2/MYB76 and HAG3/MYB29, along with the already characterized HAG1/MYB28, were identified as putative regulators of aliphatic glucosinolate biosynthesis. ,,Molecular and biochemical characterization of HAG2/MYB76 and HAG3/MYB29 functions was performed using transformants with increased or repressed transcript levels. Real-time PCR assays, cotransformation assays and measurements of glucosinolate contents were used to assess the impact of both MYB factors on the steady-state level of glucosinolate biosynthetic genes and accumulation of aliphatic glucosinolates. ,,Both HAG2/MYB76 and HAG3/MYB29 were shown to be positive regulators of aliphatic glucosinolate biosynthesis. Expression of promoter-,-glucuronidase (GUS) fusions indicated GUS activities in both vegetative and generative organs, with distinct characteristics for each MYB factor. HAG1/MYB28, HAG2/MYB76 and HAG3/MYB29 reciprocally transactivated each other in the control of aliphatic glucosinolate biosynthesis and downregulated the expression of genes involved in the control of indolic glucosinolate biosynthesis, pointing to a reciprocal negative regulation of these two pathways. ,,All three HAG transcription factors exert a coordinated control on aliphatic glucosinolate biosynthesis. [source] The Family Impact of Atopic Dermatitis in Children: The Role of the Parent CaregiverPEDIATRIC DERMATOLOGY, Issue 1 2003Rajesh Balkrishnan Ph.D. We conducted a cross-sectional, exploratory analysis of how parent caregivers are affected by their child's AD, and how certain parent caregiver characteristics and perceptions affect the family impact of this condition. Parent caregivers of children with AD (n = 49) were administered a survey to collect detailed data on socioeconomic status, health perceptions, and caregiving issues. Family impact of the child's AD was measured using a modified AD Family Impact Scale. Multiple regression analyses revealed that three major factors associated with the parent caregiver were correlated with large increases in the family impact scores: 1) perception that the child's condition is severe (13%, p < 0.01), 2) high use of nonmedical services for child's condition (21%, p < 0.01), and 3) financial concern about the child's condition (18%, p < 0.01). These preliminary data indicate distinct characteristics of the parent caregiver that are associated with higher family impact of AD in children. These parent caregiver factors may be important in identifying suitable audiences and areas for education for optimal management of children's AD. [source] QD technology and market prospects in the sectors of space exploration, biomedicine, defense, and securityPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2008C. A. Charitidis Abstract Quantum dots (QD) are a unique subset of nanomaterials characterized by their extraordinary quantum confinement behaviour. Even though the quantum dot industry is still in its infancy with revenues now reaching $10 million, it is expected to surpass $500 million in 2009. However, in order to leverage the full potential of the QD technology, new fabrication processes must be developed to attain high detectivity and high operating temperature (HOT) photodetector devices. The Quantum Dot Infrared Photodetectors (QDIPs) possess an immense potential for civilian and military applications due to the distinct characteristics stemming from their dimensionality , which provides 3D carrier confinement and the capacity for normal-incidence detection , and their amenability to bandgap engineering , which allows tailoring the peak and cutoff wavelengths according to custom needs. The QDIPs, especially when optimized to operate at higher temperatures, can become critical components in space exploration, defence and security, optical communication, quantum computing and cryptography, and medical imaging applications. Robust and reliable solutions for these fields will command a premium position in the marketplace as by responding to the societal need for secure electronic transactions, exponentially faster data processing, and higher quality diagnostic tools. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | |||||||||||||