Other Variations (other + variation)

Distribution by Scientific Domains

Selected Abstracts

Unconventional serine proteases: Variations on the catalytic Ser/His/Asp triad configuration

PROTEIN SCIENCE, Issue 12 2008
an Ekici, Özlem Do
Abstract Serine proteases comprise nearly one-third of all known proteases identified to date and play crucial roles in a wide variety of cellular as well as extracellular functions, including the process of blood clotting, protein digestion, cell signaling, inflammation, and protein processing. Their hallmark is that they contain the so-called "classical" catalytic Ser/His/Asp triad. Although the classical serine proteases are the most widespread in nature, there exist a variety of "nonclassical" serine proteases where variations to the catalytic triad are observed. Such variations include the triads Ser/His/Glu, Ser/His/His, and Ser/Glu/Asp, and include the dyads Ser/Lys and Ser/His. Other variations are seen with certain serine and threonine peptidases of the Ntn hydrolase superfamily that carry out catalysis with a single active site residue. This work discusses the structure and function of these novel serine proteases and threonine proteases and how their catalytic machinery differs from the prototypic serine protease class. [source]


ABSTRACT The ethics of conducting research in epidemic situations have yet to account fully for differences in the proportion and acuteness of epidemics, among other factors. While epidemics most often arise from infectious diseases, not all infectious diseases are of epidemic proportions, and not all epidemics occur acutely. These and other variations constrain the generalization of ethical decision-making and impose ethical demands on the individual researcher in a way not previously highlighted. This paper discusses a number of such constraints and impositions. It applies the ethical principles enunciated by Emmanuel et al.1 to the controversial Pfizer study in Nigeria in order to highlight the particular ethical concerns of acute epidemic research, and suggest ways of meeting such challenges. The paper recommends that research during epidemics should be partly evaluated on its own merits in order to determine its ethical appropriateness to the specific situation. Snap decisions to conduct research during acute epidemics should be resisted. Community engagement, public notification and good information management are needed to promote the ethics of conducting research during acute epidemics. Individual consent is most at risk of being compromised, and every effort should be made to ensure that it is maintained and valid. Use of data safety management boards should be routine. Acute epidemics also present opportunities to enhance the social value of research and maximize its benefits to communities. Ethical research is possible in acute epidemics, if the potential challenges are thought of ahead of time and appropriate precautions taken. [source]

Unequal Knowledges in Jharkhand, India: De-Romanticizing Women's Agroecological Expertise

Sarah Jewitt
Taking the Jharkhand region of India as a case study, this article uses empirical data to intervene in ,women, environment and development' and ecofeminist debates regarding women's environmental knowledge. The article first outlines the adoption of gender/environmental issues into development planning and considers the dangers of overestimating women's agroecological knowledges and assuming that they can easily participate in development projects. It then highlights the local complexities of environmental knowledge possession and control with reference to gender and other variations in agricultural participation, decision-making and knowledge transfers between villagers' natal and marital places. Particular emphasis is placed on the economic, socio-cultural and ,actor' related factors that supplement gender as an influence on task allocation, decision-making, knowledge distribution and knowledge articulation. The article concludes that given the socio-cultural constraints women face in accumulating and vocalizing environmental knowledge, simplistic participatory approaches are unlikely to empower them. Instead, more flexible, site-specific development initiatives (coupled with wider structural change) are required if opportunities are to be created for women to develop and use their agroecological knowledges. [source]

An international perspective on Tourette syndrome: selected findings from 3500 individuals in 22 countries

Roger D Freeman MD
We have established a multisite, international database of 3500 individuals diagnosed with Tourette syndrome (TS). The male:female ratio is 4.3:1 for the total sample, with wide variation among sites; the male excess occurs at every site. Anger control problems, sleep difficulties, coprolalia, and self-injurious behavior only reach impressive levels in individuals with comorbidity. Anger control problems are strongly correlated with comorbidity, regardless of site, region, or whether assessed by neurologists or psychiatrists. The mean age at onset of tics is 6.4 years. At all ages, about 12% of individuals with TS have no reported comorbidity. The most common reported comorbidity is attention-deficit-hyperactivity disorder. Males are more likely to have comorbid disorders than females. The earlier the age at onset, the greater the likelihood of a positive family history of tics. An understanding of the factors producing these and other variations might assist in better subtyping of TS. Because behavioral problems are associated with comorbidity, their presence should dictate a high index of suspicion of the latter, whose treatment may be at least as important as tic reduction. The established database can be used as the entry point for further research when large samples are studied and generalizability of results is important. [source]

Tests and calculations of short-circuit forces and displacements in high-voltage substations with strained conductors and droppers

N. Stein
Forschungsgemeinschaft für Elektrische Anlagen und Stromwirtschaft FCH and DKE UK 121.2 have recently completed an extensive systematic programme of short-circuit tests on substation bus bars of stranded conductors with and without droppers. The present test series, in continuation of the former studies, comprises 100-kV and 400-kV arrangements, applying the relevant parameters of the former. Apart from other variations, different current paths were studied for the arrangements with droppers. The present paper is confined to giving a survey of the 100-kV arrangements, parameter variations, measurements and test results, as far as they presently relate to the calculation procedure oflEC, CENELEC and D/V/VDE. It is further reported on studies with the Finite-Element Method (FEM) which show a remarkable comparative accuracy. Finally, the standardized method of IEC 60865-1 and EN 60865-1 for the calculation of short-circuit tensile forces is extended onto arrangements with droppers. [source]

Inherited defects of coagulation Factor V: the thrombotic side

Summary., DNA variations in the Factor V gene have played a major role in thrombosis research ever since the discovery of Factor V Leiden. Here, all relatively common DNA variations in the coding regions of the Factor V gene are discussed. Many of them have been associated with venous thrombosis or related diseases. However, most variations have been studied separately, without taking the presence of other variations in the same gene into account. This means that their association with disease should be interpreted with caution, as it may reflect linkage with another variation. An approach in which a haplotype-based analysis of the Factor V gene is combined with in vitro assays of recombinant proteins is advocated. Finally, a possible reason for the relatively polymorphic nature of the Factor V protein is discussed. [source]

On the power of BFS to determine a graph's diameter,

Derek G. Corneil
Abstract Recently, considerable effort has been spent on showing that Lexicographic Breadth First Search (LBFS) can be used to determine a tight bound on the diameter of graphs from various restricted classes. In this paper, we show that, in some cases, the full power of LBFS is not required and that other variations of Breadth First Search (BFS) suffice. The restricted graph classes that are amenable to this approach all have a small constant upper bound on the maximum-sized cycle that may appear as an induced subgraph. We show that, on graphs that have no induced cycle of size greater than k, BFS finds an estimate of the diameter that is no worse than diam(G) , ,k/2,. © 2003 Wiley Periodicals, Inc. [source]

ORIGINAL ARTICLE: Leptin Gene (TTTC)n Microsatellite Polymorphism as well as Leptin Receptor R223Q and PPAR,2 P12A Substitutions are not Associated with Hypertensive Disorders in Pregnancy

Annette Wiedemann
Citation Wiedemann A, Vocke F, Fitzgerald JS, Markert UR, Jeschke U, Lohse P, Toth B. Leptin gene (TTTC)n microsatellite polymorphism as well as Leptin receptor R223Q and PPAR,2 P12A substitutions are not associated with hypertensive disorders in pregnancy. Am J Reprod Immunol 2010; 63: 310,317 Problem, Pregnancy-induced hypertension (PIH) affects up to 15% of all pregnancies. Disturbed placentation is one factor associated with PIH. Leptin and peroxisome proliferator activator receptors (PPAR) seem to play an important role in placentation, fetal development, and blood pressure regulation. Therefore, we investigated polymorphisms in the genes encoding leptin, the leptin receptor, and PPAR,2 in patients with PIH. Method of study, In this retrospective case,control study, 103 patients with PIH [gestational hypertension (GH) n = 39; preeclampsia n = 27; eclampsia n = 5; HELLP n = 32] and 100 controls were analyzed for the LEP tetranucleotide repeat (TTTC)n and the leptin receptor (LEPR) R223Q and PPAR,2 P12A substitutions. Statistical analysis was performed using the chi-square, Mann,Whitney U -, and Kruskal,Wallis tests (P < 0.05 significant). Results, The frequency of the three possible genotypes did not differ significantly between patients and controls [LEP (TTTC)n: P = 0.43; LEPR R223Q: P = 0.94; PPAR,2 P12A: P = 0.94]. However, postpartal diastolic blood pressure of PIH patients was significantly higher in homozygous carriers of the LEPR Q223-encoding allele as compared with patients carrying the wild-type allele (P < 0.01). Conclusion, Hypertensive disorders in pregnancy were not associated with the LEP, LEPR, and PPAR,2 polymorphisms studied. The role of other variations in the LEP and PPAR genes in the pathophysiology of PIH and in exacerbations are the objective of ongoing research. [source]