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Search Results: 1 - 10 of 1124 matches for " Saumitra Chowdhury "
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Hadronic light-by-light scattering contribution to the muon anomalous magnetic moment from lattice QCD
Thomas Blum,Saumitra Chowdhury,Masashi Hayakawa,Taku Izubuchi
Physics , 2014, DOI: 10.1103/PhysRevLett.114.012001
Abstract: The form factor that yields the light-by-light scattering contribution to the muon anomalous magnetic moment is computed in lattice QCD+QED and QED. A non-perturbative treatment of QED is used and is checked against perturbation theory. The hadronic contribution is calculated for unphysical quark and muon masses, and only the diagram with a single quark loop is computed. Statistically significant signals are obtained. Initial results appear promising, and the prospect for a complete calculation with physical masses and controlled errors is discussed.
Role of Satellite Sensors in Groundwater Exploration
Saumitra Mukherjee
Sensors , 2008, DOI: 10.3390/s8032006
Abstract: Spatial as well as spectral resolution has a very important role to play in water resource management. It was a challenge to explore the groundwater and rainwater harvesting sites in the Aravalli Quartzite-Granite-Pegmatite Precambrian terrain of Delhi, India. Use of only panchromatic sensor data of IRS-1D satellite with 5.8-meter spatial resolution has the potential to infer lineaments and faults in this hard rock area. It is essential to identify the location of interconnected lineaments below buried pediment plains in the hard rock area for targeting sub-surface water resources. Linear Image Self Scanning sensor data of the same satellite with 23.5-meter resolution when merged with the panchromatic data has produced very good results in delineation of interconnected lineaments over buried pediment plains as vegetation anomaly. These specific locations of vegetation anomaly were detected as dark red patches in various hard rock areas of Delhi. Field investigation was carried out on these patches by resistivity and magnetic survey in parts of Jawaharlal Nehru University (JNU), Indira Gandhi national Open University, Research and Referral Hospital and Humayuns Tomb areas. Drilling was carried out in four locations of JNU that proved to be the most potential site with ground water discharge ranging from 20,000 to 30,000 liters per hour with 2 to 4 meters draw down. Further the impact of urbanization on groundwater recharging in the terrain was studied by generating Normalized difference Vegetation Index (NDVI) map which was possible to generate by using the LISS-III sensor of IRS-1D satellite. Selection of suitable sensors has definitely a cutting edge on natural resource exploration and management including groundwater.
Cosmic Influence on the Sun-Earth Environment
Saumitra Mukherjee
Sensors , 2008, DOI: 10.3390/s8127736
Abstract: SOHO satellite data reveals geophysical changes before sudden changes in the Earth's Sun-Earth environment. The influence of extragalactic changes on the Sun as well as the Sun-Earth environment seems to be both periodic and episodic. The periodic changes in terms of solar maxima and minima occur every 11 years, whereas the episodic changes can happen at any time. Episodic changes can be monitored by cosmic ray detectors as a sudden increase or decrease of activity. During these solar and cosmic anomaly periods the environment of the Earth is affected. The Star-Sun-Earth connection has the potential to influence the thermosphere, atmosphere, ionosphere and lithosphere. Initial correlation of the cosmic and Sun-Earth connection has shown the possibility of predicting earthquakes, sudden changes in atmospheric temperatures and erratic rainfall/snowfall patterns.
Role of Satellite Sensors in Groundwater Exploration
Saumitra Mukherjee
Sensors , 2008,
Abstract: Spatial as well as spectral resolution has a very important role to play in water resource management. It was a challenge to explore the groundwater and rainwater harvesting sites in the Aravalli Quartzite-Granite-Pegmatite Precambrian terrain of Delhi, India. Use of only panchromatic sensor data of IRS-1D satellite with 5.8-meter spatial resolution has the potential to infer lineaments and faults in this hard rock area. It is essential to identify the location of interconnected lineaments below buried pediment plains in the hard rock area for targeting sub-surface water resources. Linear Image Self Scanning sensor data of the same satellite with 23.5-meter resolution when merged with the panchromatic data has produced very good results in delineation of interconnected lineaments over buried pediment plains as vegetation anomaly. These specific locations of vegetation anomaly were detected as dark red patches in various hard rock areas of Delhi. Field investigation was carried out on these patches by resistivity and magnetic survey in parts of Jawaharlal Nehru University (JNU), Indira Gandhi national Open University, Research and Referral Hospital and Humayuns Tomb areas. Drilling was carried out in four locations of JNU that proved to be the most potential site with ground water discharge ranging from 20,000 to 30,000 liters per hour with 2 to 4 meters draw down. Further the impact of urbanization on groundwater recharging in the terrain was studied by generating Normalized difference Vegetation Index (NDVI) map which was possible to generate by using the LISS-III sensor of IRS-1D satellite. Selection of suitable sensors has definitely a cutting edge on natural resource exploration and management including groundwater.
Perils of Prolonged Impaction of Oesophageal Foreign Bodies
Saumitra Saha,Anandabrata Bose
ISRN Surgery , 2011, DOI: 10.5402/2011/621682
Abstract: Ill-conceived effort at removal of impacted foreign bodies (FBs) in oesophagus vies with delay in removal as the causes of morbidity and mortality. Most oesophageal FBs are safely removed endoscopically when attempted early. However, large sharp FBs like dentures and meat bones can get deeply embedded in the wall with prolonged impaction or injudicious attempts at removal leading to life-threatening mediastinitis. Open surgery to access the oesophageal-impacted FB in such an event is hazardous. This report emphasizes the need for early site-specific surgical approaches that may be required, albeit rarely, for oesophageal-impacted FBs, where attempts at endoscopic removal have failed or complications have ensued. 1. Introduction Accidentally ingested foreign body is a common emergency, presenting to the otolaryngologists, gastroenterologists, gastrointestinal surgeons, and thoracic surgeons. Over 90% of them pass uneventfully through the gastrointestinal tract [1]. Of those lodged in the oesophagus, most are removed uneventfully with an endoscope. We report three patients where endoscopic removal failed or was not attempted; the resulting delay posed considerable difficulty in treatment and necessitated three different surgical approaches to the oesophagus in the face of life-threatening infection. 2. Case Report Patient 1 A 60-year-old malnourished woman presented with dysphagia, fever, and retrosternal pain 7 days after accidental ingestion of a two-tooth denture with metal clasps. A chest X-ray (CXR) showed the metal clasps of the prosthesis in the region of the junction of mid and lower third oesophagus. Two attempts at flexible endoscopic removal elsewhere, 24 hours apart, was unsuccessful. A repeat videoendoscopy at our hospital showed an impacted denture at 29 cms (from the incisor teeth) with adjacent mucosal sloughing (Figure 1) which could not be dislodged. She was subjected to rigid oesophagoscopy under general anaesthesia (GA) which also failed to extract the denture. There was no option but to proceed to an urgent left thoracotomy through the 7th intercostal space. An oesophagotomy below the aortic arch revealed the denture with its hooks deeply embedded in an extremely thickened and oedematous oesophageal wall. The oesophagotomy was repaired using interrupted Vicryl sutures with a buttress of mediastinal pleura. A feeding jejunostomy was inserted (so that early enteral nutrition could be provided and continued in an event of leak), in addition to nasogastric tube and chest drains. On the 7th postoperative day, a CXR revealed moderate left
Investigation of tectonic processes in the lunar South Polar Region using Mini-SAR and other data
Saumitra Mukherjee,Priyadarshini Singh
Frontiers in Earth Science , 2014, DOI: 10.3389/feart.2014.00006
Abstract:
Relationships, Human Behaviour and Financial Transactions  [PDF]
Mehdi Chowdhury
Theoretical Economics Letters (TEL) , 2014, DOI: 10.4236/tel.2014.49108
Abstract: It is widely known that relationships and human behaviours such as trust, reciprocity and altruism that are observed in the human societies are capable of facilitating financial transactions. This paper proposes a theoretical model to argue that though these elements can facilitate financial transactions, they may not always ensure efficiency in the sense of creation of additional wealth. As financial resources are scarce, the paper argues that the financial transactions induced by relationships, trust, reciprocity and altruism may lead to inefficient allocations of resources.
Influence of Rice Straw Incorporation on the Microbial Biomass and Activity in Coastal Saline Soils of Bangladesh  [PDF]
Nasrin Chowdhury
Open Journal of Soil Science (OJSS) , 2016, DOI: 10.4236/ojss.2016.610016
Abstract: Coastal soils of Bangladesh are affected by salinity. This study investigated salinity as a stress factor on coastal soils in Bangladesh. It was also observed if incorporation of rice straw could remediate negative impacts of soil salinity (if any) on microbial activ-ity. The microbial biomass carbon ranged from 137.85 to 614.88 μg/g among the soils (n = 11). Microbial biomass carbon content and number of both cultivable bacteria and fungi decreased in the soils with higher ECes (electrical conductivity). Respiration was measured over 30 days with each soil pre incubated at 50% of water holding capacity. Basal respiration rate as well as soil organic carbon content (r = 0.88, p < 0.05) increased with increasing ECe of soils. The cumulative basal soil respiration was higher in the soils with higher salinity (4.81 - 37.73 mS/cm) (12.91 - 16.89 mg CO2/g dry soil) than in the nonsaline soils (0.98 - 2.33 mS/cm) (5.79 - 6.51 mg CO2/g dry soil). Application of rice straw at 0.50%, 1.00%, 1.50% and 2.00% reduced the negative impact of soil salinity especially at higher ECes (6.63 - 37.73 mS/cm). Application of 1.00% rice straw appeared to be acceptable for successful amelioration of saline soils of the study area.
A novel genetic approach for optimized biological sequence alignment  [PDF]
Gautam Garai, Biswanath Chowdhury
Journal of Biophysical Chemistry (JBPC) , 2012, DOI: 10.4236/jbpc.2012.32022
Abstract: Biological sequence alignment is one of the most important problems in computational biology. The objective of the alignment process is to maximize the alignment score between two given sequences of varying or equal length. The alignment score of two sequences is calculated based on matches, mismatches and gaps in the alignment. We have proposed a new genetic approach for finding optimized match between two DNA or protein sequences. The process is compared with two well known relevant sequence alignment techniques.
pH-responsive magnesium- and carbonate-substituted apatite nano-crystals for efficient and cell-targeted delivery of transgenes  [PDF]
Ezharul Hoque Chowdhury
Open Journal of Genetics (OJGen) , 2013, DOI: 10.4236/ojgen.2013.32A1005
Abstract:

The short half-lives due to the enzymatic degradation in blood, the lack of tissue targetability and the incapability to passively diffuse across the plasma membrane and smoothly traffic across the harsh intracelluar environment are the major shortcomings for nucleic acid-based potential therapeutics, such as recombinant plasmid and antisense oligonucleotides or small interferring RNA (siRNA). Plasmid DNA containing a gene of interest could have immense impact as a promising therapeutic drug for treating genetic as well as acquired human diseases at the molecular level with high level of efficacy and precision. Thus both viral and non-viral synthetic vectors have been developed in the past decades to address the aforementioned challenges of naked DNA. While in the viral particles plasmid DNA is integrated into the viral genome, in most non-viral cases the DNA being anionic in nature is electrostatically associated with a cationic lipid or polymer forming lipoplex or polyplex, respectively, or a cationized inorganic gold, silica or iron oxide particle. Due to the potential immunogenicity and carcinogenicity issues with the viral particles, non-viral vectors have drawn much more attention for the clinical evaluation. However, the main concern of using non-biodegradable particles, specially the inorganic ones, is the adverse effects owing to their long term interactions with body components. We have recently developed biodegradable pH-sensitive inorganic nanoparticles of Mg/CaPi and carbonate apatite for efficient transgene delivery to primary, cancer and embryonic stem cells, by virtue of their high affinity binding with the DNA, ability to contact the cell membrane by ionic or ligand-receptor interactions and fast dissolution kinectis in endosomal acidic pH facilitating release of the DNA from the dissolving particles and also from the endosomes.

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