oalib

OALib Journal期刊

ISSN: 2333-9721

费用:99美元

投稿

时间不限

2017 ( 245 )

2016 ( 371 )

2015 ( 5789 )

2014 ( 7565 )

自定义范围…

匹配条件: “Surjya K. Saikia” ,找到相关结果约138347条。
列表显示的所有文章,均可免费获取
第1页/共138347条
每页显示
Review on Periphyton as Mediator of Nutrient Transfer in Aquatic Ecosystems
Surjya K. Saikia
Ecologia Balkanica , 2011,
Abstract: In the studies of aquatic ecology, periphyton has been uncared for despite its vital role in nutrient uptake and transfer to the upper trophic organisms. Being the component of food chain as attached organism it takes part in nutrient cycling in the ecosystem like that of suspended planktonic counterparts. The present review, with an aim to understand the role of periphyton in nutrient transfer from benthic environment to upper trophic level, focuses many aspects of periphyton-nutrient relationship based on available literatures. It also attempts to redefine periphyton, as a part of biofilm, harboring nutrient components like protein, fat and carbohydrate preferably in its extracellular polymeric substance (EPS), cyanobacteria, diatom and other algal communities. In addition to physical processes, nutrient uptake by periphyton is catalyzed by enzymes like Nitrogen Reductase and Alkaline Phosphatase from the environment. This uptake and transfer is further regulated by periphytic C: nutrient (N or P) stoichiometry, colonization time, distribution of periphyton cover on sediments and macrophytes, macronutrient concentration, grazing, sloughing, temperature, and advective transport. The Carbon (C) sources of periphyton are mainly dissolve organic matter and photosynthetic C that enters into higher trophic levels through predation and transfers as C-rich nutrient components. Despite of emerging interests on utilizing periphyton as nutrient transfer tool in aquatic ecosystem, the major challenges ahead for modern aquatic biologists lies on determining nutrient uptake and transfer rate of periphyton, periphytic growth and simulating nutrient models of periphyton to figure a complete energy cycle in aquatic ecosystem.
Fuzzy Small Submodule and Jacobson -Radical
Saifur Rahman,Helen K. Saikia
International Journal of Mathematics and Mathematical Sciences , 2011, DOI: 10.1155/2011/980320
Abstract: Using the notion of fuzzy small submodules of a module, we introduce the concept of fuzzy coessential extension of a fuzzy submodule of a module. We attempt to investigate various properties of fuzzy small submodules of a module. A necessary and sufficient condition for fuzzy small submodules is established. We investigate the nature of fuzzy small submodules of a module under fuzzy direct sum. Fuzzy small submodules of a module are characterized in terms of fuzzy quotient modules. This characterization gives rise to some results on fuzzy coessential extensions. Finally, a relation between small -submodules and Jacobson -radical is established.
6,6′-Diamino-1,1′,3,3′-tetramethyl-5,5′-(4-chlorobenzylidene)bis[pyrimidine-2,4(1H,3H)-dione]
Subrata Das,Binoy K. Saikia,Babulal Das,Lakhinath Saikia
Acta Crystallographica Section E , 2009, DOI: 10.1107/s1600536809035818
Abstract: The title compound, C19H21ClN6O4, is a 1:2 adduct of p-chlorobenzaldehyde and uracil. It crystallizes with two molecules in the asymmetric unit. The two uracil units in the same molecule are connected by a pair of strong N—H...O hydrogen bonds. The packing is stabilized by N—H...O, C—H...O and C—H...N interactions.
Titanium elastic nailing in femoral diaphyseal fractures of children in 6-16 years of age
Saikia K,Bhuyan S,Bhattacharya T,Saikia S
Indian Journal of Orthopaedics , 2007,
Abstract: Background: Management of femoral diaphyseal fractures in the age group of 6-16 years is contro versial. There has been a resurgence world wide for operative fixation. Materials and Methods: Twenty-two children (18 boys, 4 girls) aged 6-16 years with recent (< 3 days) femoral diaphyseal fractures (20 closed, 2 open) were stabilized with Titanium Elastic Nail (TEN). These fractures were in proximal third (n=3), middle third (n=15) and in the distal third (n=4) 17 patients underwent surgery with in seven days of their injury. The results were evaluated using Flynn′s scoring criteria. Statistical analysis was done using Fischer′s exact test. Results : All 22 patients were available for evaluation after a mean of 26 months (14-36 months) of follow-up. Radiological union in all cases were achieved in a mean time of 8.7 weeks. Full weight bearing was possible in a mean time of 8.8 wks. Mean duration of hospital stay was 9.8 days. The results were excellent in 13 patients (59.0%), successful in six (27.2%) and poor in three patients (13.6%). All patients had early return to school. Conclusion : Intramedullary titanium elastic nailing is an effective treatment of diaphyseal fractures of femur in properly selected patients of 6-16 years age group.
Pentacene based thin film transistors with high-k dielectric Nd2O3 as a gate insulator
Sarma, R.;Saikia, D.;Saikia, Puja;Saikia, P.K.;Baishya, B.;
Brazilian Journal of Physics , 2010, DOI: 10.1590/S0103-97332010000300019
Abstract: we have investigated the pentacene based organic thin film transistors (otfts) with high-k dielectric nd2o3. use of high dielectric constant (high-k) gate insulator nd2o3 reduces the threshold voltage and sub threshold swing of the otfts. the calculated threshold voltage -2.2v and sub-threshold swing 1v/decade, current on-off ratio is 1.7 × 104 and mobility is 0.13cm2/v.s. pentacene film is deposited on nd2o3 surface using two step deposition method. deposited pentacene film is found poly crystalline in nature.
Asymmetric Synthesis of Naturally Occuring Spiroketals
B. Rama Raju,Anil K. Saikia
Molecules , 2008, DOI: 10.3390/molecules13081942
Abstract: Spiroketals are widely found as substructures of many naturally occurring compounds from diverse sources including plants, animals as well as microbes. Naturally occurring spiroketals are biologically active and most of them are chiral molecules. This article aims at reviewing the asymmetric synthesis of biologically active spiroketals for last 10 years (1998-2007).
C and P in aquatic food chain: A review on C:P stoichiometry and PUFA regulation C et P dans les cha nes alimentaires aquatiques : une revue sur la stoechimétrie C:P et la régulation par les PUFA
Saikia S.K.,Nandi S.
Knowledge and Management of Aquatic Ecosystems , 2010, DOI: 10.1051/kmae/2010024
Abstract: Carbon (C) and phosphorous (P) regulation in aquatic food chains are transferred from lower to upper trophic levels primarily as polyunsaturated fatty acids (PUFAs) and C:P stoichiometry. The majority of C is transferred through algal based pathway. Microbial loop, though optionally contributes to C transfer, highly constrained by P limitation and bacterial predator type. Lack of essential PUFAs in bacteria is also responsible for its low trophic transfer of C. The seston size and algal taxonomic variations directly affect herbivore through P-dependent food quality and de novo synthesis of PUFAs. Change in algal community over a gradient could therefore determine C transfer. Feeding nature (herbivorous or carnivorous) and predator sizes also regulate transfer efficiency of C and P to upper trophic levels. As trophic levels move up, P-limitation becomes higher compared to autotrophs. For Daphnia, as mostly studied aquatic herbivore member, P limitation becomes critical at C:P > 300 indicating excess C is not always invited under P-deficient situations. However, as a part of homeostasis mechanism for trophic upgrading, conversion of algal-zooplankton interface from qualitative to quantitative could minimize such critical C:P regulation at higher trophic levels. Protists, in turn, with high clearance rate by zooplankton predator could also compensate qualitative effect. Les régulations par carbone (C) et phosphore (P) dans les cha nes trophiques aquatiques sont transférées des niveaux trophiques inférieurs vers les supérieurs au travers des acides gras polyinsaturés (PUFAs) et du rapport stoechiométrique C:P. La majorité du C est transférée par la voie reposant sur les algues. La boucle microbienne, bien que contribuant au transfert du C, est très contrainte par la limitation en P et la prédation. Un manque de PUFAs essentiels est également responsable de ce faible transfert du C. La taille du seston et les variations taxonomiques des algues affectent directement les herbivores au travers de la qualité nutritionnelle dépendante du P et de la synthèse de novo de PUFAs. Le type de nourriture (herbivorie ou carnivorie) et les tailles de prédateurs régulent aussi l’efficacité du transfert de C et P vers les niveaux trophiques supérieurs. La limitation par P devient plus importante dans les niveaux trophiques supérieurs. Pour Daphnia, comme pour beaucoup d’organismes herbivores étudiés, la limitation par P devient cruciale quand C:P > 300, indiquant un excès de C pas toujours d à des situations de déficience en P. Toutefois, comme part du mécanisme d’homéostas
Anthropometric study of the hip joint in Northeastern region population with computed tomography scan
Saikia K,Bhuyan S,Rongphar R
Indian Journal of Orthopaedics , 2008,
Abstract: Background: Anthropometric study of the hip joint has important clinical implications and is largely unknown for the northeastern region of India. The purpose of this study is to determine the anatomic variation of the normal hip joint among the people of the northeastern region and to statistically compare them with the available data worldwide. Materials and Methods: We evaluated 104 individuals with normal hip joints and of different ethnic backgrounds (Caucasoid and Mongoloids) clinically and by plain x- ray. One topogram of the hip joint, one axial section of the femoral head and femoral condyles of the individual was taken on CT scan. Twelve cases had center edge angle (CE) angle less than 20° (unilateral/bilateral), were considered to be dysplastic and were excluded from the study. Thus the present study includes 92 individuals (184 normal hips, Mongoloids = 45; Caucasoid = 47) between 20-70 years of age. We calculated the mean of the CE angle, acetabular angle, neck shaft angle, acetabular version, femoral neck anteversion, acetabular depth and joint space width in both sexes. Results: The mean parameters observed were as follows: acetabular angle 39.2°, centre edge angle 32.7°, neck shaft angle 139.5°, acetabular version 18.2°, femoral neck anteversion 20.4°, acetabular depth 2.5 cm and joint space width 4.5 mm. Conclusion: The parameter and its values in our series shows differences when compared to the other western literatures. The neck shaft angle and the femoral neck anteversion in our individuals was 5-6° more than the western literature. The remaining parameters were less or equal to the western literature.
Anterior compartment pressure measurement in closed fractures of leg
Saikia K,Bhattacharya T,Agarwala V
Indian Journal of Orthopaedics , 2008,
Abstract: Background: Compartment syndrome is a potentially devastating condition. Increased intracompartmental pressure has been incriminated as the primary pathogenic factor in compartment syndrome. The purpose of this prospective study was to monitor the anterior compartmental pressure and differential pressure to minimize the incidence of acute compartment syndrome. Materials and Methods: Seventy-five consecutive cases of closed fractures of leg presenting within six hours of injury were taken for measurement of anterior compartment pressure at the level of fracture and at 5 cm and 10 cm away from the fracture site, using the Whitesides′ infusion technique. A differential pressure of less than 30 mm Hg was taken as the criterion for diagnosis of compartment syndrome. Results: Two patients (2.67%) developed acute compartment syndrome. The mean anterior compartment pressures were highest at the level of the fracture and went on decreasing as we went away from the fracture site, which was found to be statistically significant ( p < 0.001). Conclusion: Compartment pressure measurement is the most reliable and objective method for early diagnosis of compartment syndrome. Whitesides′ infusion technique is a relatively easy and inexpensive method to come to a diagnosis of compartment syndrome in a developing country like India. Differential pressure is more reliable than absolute pressure in predicting the development of an impending compartment syndrome.
Clutch size and egg characteristics of Cotton Pygmy-Goose in Assam (India)
S. Upadhyaya,P.K. Saikia
Asian Journal of Conservation Biology , 2012,
Abstract: The reproductive output of the waterfowl depends on the nutrients present in the eggs. The average clutch of each species of waterfowl has been evolved in relation to the average availability of food for the female around the time of laying, modified by the relative size of the egg. It has been also suggested that the species laying eggs that were small, relative to their body size, would be able to lay many eggs, whereas species laying large eggs would lay fewer eggs. The Cotton Pygmy-goose eggs were light creamy white or light ivory white in colour on the day of laying with the mean size of 13.94 +0.4 SD. The overall clutch size found was 14.2. The mean size of the eggs ranges between 13.50 to 14.76 cm2 (mean= 13.94 +0.4 SD). The overall mean length of the egg was found to be 42.8 mm +0.7 SD (range 42.0 – 44.6 mm, n=21), whereas the mean egg width was 32.4 mm +0.5 SD (range =31.5 – 33.1 mm, n=21). A strong positive and significant relationship exists between egg length and width (r= 0.8 & p= 0.0001). The mean weight of the eggs was found to be 25.006 +0.2 SD (range: 24.5 to 25.75 gm). Standard methodology was followed to execute the study. The present paper deals with the study of clutch size and various characteristics of eggs of the species in concern and their relation with the female.
第1页/共138347条
每页显示


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.