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Papers by Akhil.P Chandran
Climate Change and Environmental Sustainability, 2013
Global importance of total organic carbon (TOC) in soil is due to its role in the global carbon c... more Global importance of total organic carbon (TOC) in soil is due to its role in the global carbon cycle and, thus, the part it plays in influencing the atmospheric levels of greenhouse gases (GHGs). It is also of local importance as it determines ecosystem and agro-ecosystem function, influencing various soil parameters. The objective of the present study was to evaluate RothC model (26.3) to estimate TOC changes under two long term fertilizer experimental (LTFE) sites representing humid (Mohanpur) and semi-arid (Akola) climate in India. Five treatments each at the LTFE sites of Mohanpur representing alluvial soils (Alfisol) of the Indo-Gangetic Plains (IGP) and of Akola dominated by black soils (Vertisols) in the Black Soil Region (BSR) were selected. Mohanpur site was modelled for 3 layers (0–13, 13–23, and 23–39 cm) while Akola for surface layer (0–15 cm) only. The root mean square error (RMSE), considered as modelling error, ranged from 3.34 to 17.85%, 6.87 to 14.22% and 6.66 to 24.34% in the 3 soil layers of Mohanpur site respectively. For Akola, RMSE ranges from 1.79 to 13.28. The simulation biases expressed by M (relative error) for all treatments at these sites were non-significant. In Mohanpur, observed trends in TOC show marginal increase in control (T1) and 100% NPK (T2) while the increase was nearly 17 to 35% when organic amendments were applied along with inorganics during 1999 to 2010. For the same period in Akola, control (T1), 50% NPK (T2), and 100% NPK (T4) recorded decrease in TOC while 26 to 29% increase was registered without inorganics and with the combination of inorganics and organics respectively. The calculation of modelled TOC stock to find out effect of global warming indicated that treating the entire soil pedon as a homogenous unit will overestimate effects of global warming in accelerating decomposition of soil carbon.
Crystal Growth & Design, 2014
Current science
The articles presented in this special section emanated from the researches of consortium members... more The articles presented in this special section emanated from the researches of consortium members of the National Agricultural Innovative Project (NAIP, Component 4) of the Indian Council of Agricultural Research (ICAR), New Delhi. These researches have helped develop a soil information system (SIS). In view of the changing scenario all over the world, the need of the hour is to get assistance from a host of re-searchers specialized in soils, crops, geology, geogra-phy and information technology to make proper use of the datasets. Equipped with the essential knowledge of data storage and retrieval for management recom-mendations, these experts should be able to address the issues of land degradation, biodiversity, food
ABSTRACT In view of lack of precise information on the factors and processes in clay illuviation,... more ABSTRACT In view of lack of precise information on the factors and processes in clay illuviation, pedoturbation and slickenside formation in shrink-swell soils, a study on a <100 years old shrink-swell soil (Vertic Haplustalf) of Central India was undertaken. The soil has typical physical, chemical and mineralogical properties of Vertisols but lack in slickensides. Detailed physical, chemical and micromorphological data indicate the presence of argillic horizon characterized by impure clay pedofeatures in voids and poorly separated plasma. The study proves a fact that clay illuviation is more important pedogenetic process than pedoturbation. A time of a century is not adequate for the formation of slickensides that are hitherto considered to be a rapid pedogenetic process for structure formation in Vertisols. The study suggests a highly probable pathway for the formation of Vertisols with time from Vertic Alfisols in sub-humid and semi-arid climatic conditions of central India.
Proceedings of the International Conference on Advances in Computing, Communications and Informatics, 2012
Cloud computing has evolved as a popular computing environment. In data centric applications host... more Cloud computing has evolved as a popular computing environment. In data centric applications hosted on the cloud, data is accessed and updated in a purely distributed manner. The distributed data structures used for dynamic storage of the data for such applications require two fundamental qualities, authentication and persistence, which are not completely met by existing distributed data structures. Authentication is
The Surgeon, 2003
The precise cause(s) of Crohn's disease and ulcerative colitis are unknown. From animal m... more The precise cause(s) of Crohn's disease and ulcerative colitis are unknown. From animal models and human studies it is well established that gut bacterial flora are essential for inducing the bowel inflammation. Animal models, when kept in a germ-free environment, do not develop colitis until the gut flora is reconstituted. It is not clear whether the bacterial antigens (Ags) from the normal flora or some other pathogenic bacterial Ags induce/propagate the inflammatory process in inflammatory bowel disease (IBD). Despite extensive research it has not been possible to identify any specific bacteria or virus as a credible cause of IBD. Recent understanding of quorum sensing molecules (QSMs) secreted by bacteria helps to explain the community behaviour in bacterial species. When QSMs reach a defined concentration, they activate bacterial proliferation and a number of virulence genes. Also, these molecules have been found to modulate the immune system to the advantage of the gut bacteria. They have not been well studied, however, in the gut. Inappropriate secretion of QSMs may alter the gut-associated lymphoid tissue (GALT) and, thereby, deregulate the immune tolerance normally present. Usefulness of probiotics and their immune modulating effects are being increasingly reported. Probiotics are also being used in the treatment of IBD. The interaction between the epithelial cells and the gut flora is very important as this is the first line of contact; this interaction may determine the induction of tolerance and mucosal integrity or immune activity, tissue inflammation and abnormal permeability. The latter is documented in patients with IBD and their healthy relatives. This may be an important factor in disruption of mucosal integrity and GALT dysfunction.
Soil Research, 2005
In this study, we report the chemical and mineralogical characteristics of 4 benchmark Ultisols o... more In this study, we report the chemical and mineralogical characteristics of 4 benchmark Ultisols of Kerala to elucidate their genesis and taxonomy. The taxonomic rationale of the mineralogy class of Ultisols and other highly weathered soils on the basis of the contemporary pedogenesis is also explained. The Ultisols of Kerala have low pH, low cation exchange capacity, low effective cation exchange capacity and base saturation, with dominant presence of 1 : 1 clays and gibbsite. Presence of gibbsite along with 2 : 1 minerals discounts the hypothesis of anti-gibbsite effect. Since the kaolins are interstratified with hydroxy-interlayered vermiculites (HIV), the formation of gibbsite from kaolinite is not tenable. Thus, gibbsite is formed from primary minerals in an earlier alkaline pedo-environment. Therefore, the presence of gibbsite does not necessarily indicate an advanced stage of weathering. On the basis of a dominant amount of gibbsite, a mineralogy class such as allitic or gibbs...
NeuroImage, 2013
The earliest stages of osteoarthritis are characterized by peripheral pathology; however, during ... more The earliest stages of osteoarthritis are characterized by peripheral pathology; however, during disease progression chronic pain emerges-a major symptom of osteoarthritis linked to neuroplasticity. Recent clinical imaging studies involving chronic pain patients, including osteoarthritis patients, have demonstrated that functional properties of the brain are altered, and these functional changes are correlated with subjective behavioral pain measures. Currently, preclinical osteoarthritis studies have not assessed if functional properties of supraspinal pain circuitry are altered, and if these functional properties can be modulated by pharmacological therapy either by direct or indirect action on brain systems. In the current study, functional connectivity was first assessed in order to characterize the functional neuroplasticity occurring in the rodent medial meniscus tear (MMT) model of osteoarthritis-a surgical model of osteoarthritis possessing peripheral joint trauma and a hypersensitive pain state. In addition to knee joint trauma at week 3 post-MMT surgery, we observed that supraspinal networks have increased functional connectivity relative to sham animals. Importantly, we observed that early and sustained treatment with a novel, peripherally acting broad-spectrum matrix metalloproteinase (MMP) inhibitor (MMPi) significantly attenuates knee joint trauma (cartilage degradation) as well as supraspinal functional connectivity increases in MMT animals. At week 5 post-MMT surgery, the acute pharmacodynamic effects of celecoxib (selective cyclooxygenase-2 inhibitor) on brain function were evaluated using pharmacological magnetic resonance imaging (phMRI) and functional connectivity analysis. Celecoxib was chosen as a comparator, given its clinical efficacy for alleviating pain in osteoarthritis patients and its peripheral and central pharmacological action. Relative to the vehicle condition, acute celecoxib treatment in MMT animals yielded decreased phMRI infusion responses and decreased functional connectivity, the latter observation being similar to what was detected following chronic MMPi treatment. These findings demonstrate that an assessment of brain function may provide an objective means by which to further evaluate the pathology of an osteoarthritis state as well as measure the pharmacodynamic effects of therapies with peripheral or peripheral and central pharmacological action.
Journal of Mathematical Analysis and Applications, 1989
Journal of Materials Engineering and Performance, 2013
ABSTRACT This study has been carried out to reinforce the commonly believed fact that the dispers... more ABSTRACT This study has been carried out to reinforce the commonly believed fact that the dispersion of carbon nanotubes in a composite has a profound effect on the properties of the composite. In this study, ball milling was carried out using two different parameters to obtain distinctly different degrees of dispersion of carbon nanotubes (4 wt.%) in Al-9 wt.% Si powders. Composite disks, 80 mm in diameter, having good and bad dispersions of carbon nanotubes were obtained by hot pressing. Optical micrographs and Raman spectroscopy images showed the presence of larger carbon nanotube clusters in the bad dispersion sample. Transmission electron microscopy images confirmed the presence of large clusters in the bad dispersion sample, while the good dispersion sample showed individual carbon nanotubes in the Al matrix. Nanoindentation results indicated a 41% increase in the hardness and a 27% increase in the elastic-to-plastic work ratio, while compression tests indicated a 185% increase in compression yield strength and a 109% increase in fracture strength with improvement in carbon nanotube’s dispersion.
International Journal of Engineering Science, 1977
International Journal of Engineering Science, 1986
Abstract The effects of rotating spheres, spheroids and paraboloids on the flow and heat transfer... more Abstract The effects of rotating spheres, spheroids and paraboloids on the flow and heat transfer in the boundary layers have been investigated. The field functions corresponding to the polynomial profiles have been determined numerically. The nonlinear boundary value ...
Climate Change and Environmental Sustainability, 2013
Global importance of total organic carbon (TOC) in soil is due to its role in the global carbon c... more Global importance of total organic carbon (TOC) in soil is due to its role in the global carbon cycle and, thus, the part it plays in influencing the atmospheric levels of greenhouse gases (GHGs). It is also of local importance as it determines ecosystem and agro-ecosystem function, influencing various soil parameters. The objective of the present study was to evaluate RothC model (26.3) to estimate TOC changes under two long term fertilizer experimental (LTFE) sites representing humid (Mohanpur) and semi-arid (Akola) climate in India. Five treatments each at the LTFE sites of Mohanpur representing alluvial soils (Alfisol) of the Indo-Gangetic Plains (IGP) and of Akola dominated by black soils (Vertisols) in the Black Soil Region (BSR) were selected. Mohanpur site was modelled for 3 layers (0–13, 13–23, and 23–39 cm) while Akola for surface layer (0–15 cm) only. The root mean square error (RMSE), considered as modelling error, ranged from 3.34 to 17.85%, 6.87 to 14.22% and 6.66 to 24.34% in the 3 soil layers of Mohanpur site respectively. For Akola, RMSE ranges from 1.79 to 13.28. The simulation biases expressed by M (relative error) for all treatments at these sites were non-significant. In Mohanpur, observed trends in TOC show marginal increase in control (T1) and 100% NPK (T2) while the increase was nearly 17 to 35% when organic amendments were applied along with inorganics during 1999 to 2010. For the same period in Akola, control (T1), 50% NPK (T2), and 100% NPK (T4) recorded decrease in TOC while 26 to 29% increase was registered without inorganics and with the combination of inorganics and organics respectively. The calculation of modelled TOC stock to find out effect of global warming indicated that treating the entire soil pedon as a homogenous unit will overestimate effects of global warming in accelerating decomposition of soil carbon.
Crystal Growth & Design, 2014
Current science
The articles presented in this special section emanated from the researches of consortium members... more The articles presented in this special section emanated from the researches of consortium members of the National Agricultural Innovative Project (NAIP, Component 4) of the Indian Council of Agricultural Research (ICAR), New Delhi. These researches have helped develop a soil information system (SIS). In view of the changing scenario all over the world, the need of the hour is to get assistance from a host of re-searchers specialized in soils, crops, geology, geogra-phy and information technology to make proper use of the datasets. Equipped with the essential knowledge of data storage and retrieval for management recom-mendations, these experts should be able to address the issues of land degradation, biodiversity, food
ABSTRACT In view of lack of precise information on the factors and processes in clay illuviation,... more ABSTRACT In view of lack of precise information on the factors and processes in clay illuviation, pedoturbation and slickenside formation in shrink-swell soils, a study on a <100 years old shrink-swell soil (Vertic Haplustalf) of Central India was undertaken. The soil has typical physical, chemical and mineralogical properties of Vertisols but lack in slickensides. Detailed physical, chemical and micromorphological data indicate the presence of argillic horizon characterized by impure clay pedofeatures in voids and poorly separated plasma. The study proves a fact that clay illuviation is more important pedogenetic process than pedoturbation. A time of a century is not adequate for the formation of slickensides that are hitherto considered to be a rapid pedogenetic process for structure formation in Vertisols. The study suggests a highly probable pathway for the formation of Vertisols with time from Vertic Alfisols in sub-humid and semi-arid climatic conditions of central India.
Proceedings of the International Conference on Advances in Computing, Communications and Informatics, 2012
Cloud computing has evolved as a popular computing environment. In data centric applications host... more Cloud computing has evolved as a popular computing environment. In data centric applications hosted on the cloud, data is accessed and updated in a purely distributed manner. The distributed data structures used for dynamic storage of the data for such applications require two fundamental qualities, authentication and persistence, which are not completely met by existing distributed data structures. Authentication is
The Surgeon, 2003
The precise cause(s) of Crohn's disease and ulcerative colitis are unknown. From animal m... more The precise cause(s) of Crohn's disease and ulcerative colitis are unknown. From animal models and human studies it is well established that gut bacterial flora are essential for inducing the bowel inflammation. Animal models, when kept in a germ-free environment, do not develop colitis until the gut flora is reconstituted. It is not clear whether the bacterial antigens (Ags) from the normal flora or some other pathogenic bacterial Ags induce/propagate the inflammatory process in inflammatory bowel disease (IBD). Despite extensive research it has not been possible to identify any specific bacteria or virus as a credible cause of IBD. Recent understanding of quorum sensing molecules (QSMs) secreted by bacteria helps to explain the community behaviour in bacterial species. When QSMs reach a defined concentration, they activate bacterial proliferation and a number of virulence genes. Also, these molecules have been found to modulate the immune system to the advantage of the gut bacteria. They have not been well studied, however, in the gut. Inappropriate secretion of QSMs may alter the gut-associated lymphoid tissue (GALT) and, thereby, deregulate the immune tolerance normally present. Usefulness of probiotics and their immune modulating effects are being increasingly reported. Probiotics are also being used in the treatment of IBD. The interaction between the epithelial cells and the gut flora is very important as this is the first line of contact; this interaction may determine the induction of tolerance and mucosal integrity or immune activity, tissue inflammation and abnormal permeability. The latter is documented in patients with IBD and their healthy relatives. This may be an important factor in disruption of mucosal integrity and GALT dysfunction.
Soil Research, 2005
In this study, we report the chemical and mineralogical characteristics of 4 benchmark Ultisols o... more In this study, we report the chemical and mineralogical characteristics of 4 benchmark Ultisols of Kerala to elucidate their genesis and taxonomy. The taxonomic rationale of the mineralogy class of Ultisols and other highly weathered soils on the basis of the contemporary pedogenesis is also explained. The Ultisols of Kerala have low pH, low cation exchange capacity, low effective cation exchange capacity and base saturation, with dominant presence of 1 : 1 clays and gibbsite. Presence of gibbsite along with 2 : 1 minerals discounts the hypothesis of anti-gibbsite effect. Since the kaolins are interstratified with hydroxy-interlayered vermiculites (HIV), the formation of gibbsite from kaolinite is not tenable. Thus, gibbsite is formed from primary minerals in an earlier alkaline pedo-environment. Therefore, the presence of gibbsite does not necessarily indicate an advanced stage of weathering. On the basis of a dominant amount of gibbsite, a mineralogy class such as allitic or gibbs...
NeuroImage, 2013
The earliest stages of osteoarthritis are characterized by peripheral pathology; however, during ... more The earliest stages of osteoarthritis are characterized by peripheral pathology; however, during disease progression chronic pain emerges-a major symptom of osteoarthritis linked to neuroplasticity. Recent clinical imaging studies involving chronic pain patients, including osteoarthritis patients, have demonstrated that functional properties of the brain are altered, and these functional changes are correlated with subjective behavioral pain measures. Currently, preclinical osteoarthritis studies have not assessed if functional properties of supraspinal pain circuitry are altered, and if these functional properties can be modulated by pharmacological therapy either by direct or indirect action on brain systems. In the current study, functional connectivity was first assessed in order to characterize the functional neuroplasticity occurring in the rodent medial meniscus tear (MMT) model of osteoarthritis-a surgical model of osteoarthritis possessing peripheral joint trauma and a hypersensitive pain state. In addition to knee joint trauma at week 3 post-MMT surgery, we observed that supraspinal networks have increased functional connectivity relative to sham animals. Importantly, we observed that early and sustained treatment with a novel, peripherally acting broad-spectrum matrix metalloproteinase (MMP) inhibitor (MMPi) significantly attenuates knee joint trauma (cartilage degradation) as well as supraspinal functional connectivity increases in MMT animals. At week 5 post-MMT surgery, the acute pharmacodynamic effects of celecoxib (selective cyclooxygenase-2 inhibitor) on brain function were evaluated using pharmacological magnetic resonance imaging (phMRI) and functional connectivity analysis. Celecoxib was chosen as a comparator, given its clinical efficacy for alleviating pain in osteoarthritis patients and its peripheral and central pharmacological action. Relative to the vehicle condition, acute celecoxib treatment in MMT animals yielded decreased phMRI infusion responses and decreased functional connectivity, the latter observation being similar to what was detected following chronic MMPi treatment. These findings demonstrate that an assessment of brain function may provide an objective means by which to further evaluate the pathology of an osteoarthritis state as well as measure the pharmacodynamic effects of therapies with peripheral or peripheral and central pharmacological action.
Journal of Mathematical Analysis and Applications, 1989
Journal of Materials Engineering and Performance, 2013
ABSTRACT This study has been carried out to reinforce the commonly believed fact that the dispers... more ABSTRACT This study has been carried out to reinforce the commonly believed fact that the dispersion of carbon nanotubes in a composite has a profound effect on the properties of the composite. In this study, ball milling was carried out using two different parameters to obtain distinctly different degrees of dispersion of carbon nanotubes (4 wt.%) in Al-9 wt.% Si powders. Composite disks, 80 mm in diameter, having good and bad dispersions of carbon nanotubes were obtained by hot pressing. Optical micrographs and Raman spectroscopy images showed the presence of larger carbon nanotube clusters in the bad dispersion sample. Transmission electron microscopy images confirmed the presence of large clusters in the bad dispersion sample, while the good dispersion sample showed individual carbon nanotubes in the Al matrix. Nanoindentation results indicated a 41% increase in the hardness and a 27% increase in the elastic-to-plastic work ratio, while compression tests indicated a 185% increase in compression yield strength and a 109% increase in fracture strength with improvement in carbon nanotube’s dispersion.
International Journal of Engineering Science, 1977
International Journal of Engineering Science, 1986
Abstract The effects of rotating spheres, spheroids and paraboloids on the flow and heat transfer... more Abstract The effects of rotating spheres, spheroids and paraboloids on the flow and heat transfer in the boundary layers have been investigated. The field functions corresponding to the polynomial profiles have been determined numerically. The nonlinear boundary value ...