RAJIB BISWAS - Academia.edu (original) (raw)

Papers by RAJIB BISWAS

mSphere, 2021

Cholera is a severe dehydrating illness of humans caused by Vibrio cholerae serogroup O1 or O139.... more Cholera is a severe dehydrating illness of humans caused by Vibrio cholerae serogroup O1 or O139. Protection against cholera is serogroup specific, and serogroup specificity is defined by O-specific polysaccharide (OSP).

arXiv: Chemical Physics, 2020

Hydrophobic solutes significantly alters water hydrogen bond network. The local alteration of sol... more Hydrophobic solutes significantly alters water hydrogen bond network. The local alteration of solvation struc-tures get reflected in the vibrational spectroscopic signal. Although it is possible to detect this microscopicfeatures by modern infrared spectroscopy, however, bulk phase spectra often comes with formidable challengeof establishing the connection among the experimental spectra to molecular structures. Theoretical spec-troscopy can serve as more powerful tool even where spectroscopic data cannot provide microscopic this http URL the present work, we build a theoretical spectroscopic map based on mixed quantum-classical molecularsimulation approach using methane in water system. The single oscillator level O-H stretch frequency is wellcorrelated with a collective variable solvation energy. We construct the spectroscopic maps for fundamentaltransition frequencies and also the transition dipoles. A bimodal frequency distribution with a blue shiftedpopulation of transition freq...

Geophysical Lab, Department of Physics, Tezpur University, Tezpur-784028, Assam Corresponding aut... more Geophysical Lab, Department of Physics, Tezpur University, Tezpur-784028, Assam Corresponding author: rajib@tezu.ernet.in Kopili fault has been experiencing higher seismic and tectonic activity ([1], [2]) during the recent years. These kinds of active tectonics can be inspected by examining coda-wave attenuation and its dependence with frequency. Here, we report spatial variation of coda attenuation of this region. The obtained results reveal that there is velocity anomaly at depth 210-220 km as there arises sharp changes in attenuation coefficient (γ) and frequency parameter (n) which are supported by available data reported by other researchers for this region.

Vaccine, 2021

BACKGROUND The World Health Organization (WHO) recommends the use of oral cholera vaccines (OCVs)... more BACKGROUND The World Health Organization (WHO) recommends the use of oral cholera vaccines (OCVs) as part of an integrated control program, both in highly endemic settings and during cholera epidemics. The available and internationally recommended WHO-prequalified OCVs (Dukoral, Shanchol, Euvichol) contain multiple heat and formalin-killed V. cholerae strains of Inaba and Ogawa serotypes. MSD Wellcome Trust Hilleman Laboratories Pvt. Ltd. in technical collaboration with University of Gothenburg, Sweden has developed a new single strain OCV, Hillchol. This vaccine consists of formaldehyde-inactivated whole cell El Tor V. cholerae O1 bacteria engineered into the Hikojima serotype for stable expression of both the Ogawa (AB) and Inaba (AC) LPS antigens on the bacterial surface. We evaluated the safety and immunogenicity of this novel and potentially much less expensive OCV in comparison with Shanchol. METHODS We conducted a randomized, non-inferiority, age-descending clinical trial of OCV (Hillchol vs. Shanchol) in the Mirpur area of Dhaka city from July 2016 to May 2017. This study was carried out in three different age cohorts (1-<5, 5-17 and ≥18 years old). Two doses of vaccine were given at 14 days intervals to 560 healthy participants. FINDINGS No serious adverse events were reported. There were no significant differences in the rates of adverse events between the test vaccine (Hillchol) and the comparator (Shanchol) group. Serum vibriocidal antibody responses in all age groups combined were comparable for all the O1 Ogawa (59% vs. 67%; 90% CI of difference: -14.55, -0.84) and Inaba (70% vs. 71%; 90% CI of difference: -7.24, 5.77) serotypes, showing that the Hillchol vaccine was non-inferior to Shanchol. This new vaccine was also non-inferior to Shanchol in the different age strata. CONCLUSION The safety and immunogenicity profile of the new OCV Hillchol is comparable to Shanchol in persons residing in a cholera-endemic setting. ClinicalTrials.gov number: NCT02823899.

International Journal of Geotechnical Earthquake Engineering, 2021

Attenuation study of a province is considered as a basic quantity for seismic hazard assessment. ... more Attenuation study of a province is considered as a basic quantity for seismic hazard assessment. It has already been established that the study of two physical processes, namely the seismic sources and propagation of the waves, is essential for seismic-hazard mapping. Additionally, attenuation plays an important role towards scaling seismic hazard. Accordingly, a computational tool entitled CodaQback is presented. Based on back scattering model, this versatile software is equipped with user-friendly graphical user interface. It also allows quick picking of phases for computing coda attenuation parameter. All outputs after each execution step in CodaQback are efficiently exported step-wise into a separate folder in Excel and text formats. To validate the computing tool, it is tested in real data analysis and there is found to be good matching of computed values with already established ones. It is envisioned that this package will enable user to derive quick and reliable estimation o...

The Journal of Chemical Physics, 2020

Hydrophobic solutes significantly alter the water hydrogen bond network. The local alteration of ... more Hydrophobic solutes significantly alter the water hydrogen bond network. The local alteration of solvation structures gets reflected in the vibrational spectroscopic signal. Although it is possible to detect this microscopic feature by modern infrared spectroscopy, bulk phase spectra often come with a formidable challenge of establishing the connection of experimental spectra to molecular structures. Theoretical spectroscopy can serve as a more powerful tool where spectroscopic data cannot provide the microscopic picture. In the present work, we build a theoretical spectroscopic map based on a hybrid quantum-classical molecular simulation approach using a methane-water system. The single oscillator O-H stretch frequency is well correlated with a collective variable solvation energy. We construct the spectroscopic maps for fundamental transition frequencies and also the transition dipoles. A bimodal frequency distribution with a blue-shifted population of transition frequency illustrates the presence of gas like water molecules in the hydration shell of methane. This observation is further complemented by a shell-wise decomposition of the O-H stretch frequencies. We observe a significant increase in the ordering of the first solvation water molecules, except those which are directly facing the methane molecule. This is manifested in the redshift of the observed transition frequencies. Temperature dependent simulations depict that the water molecules facing the methane molecule behave similarly to the high temperature water, and a few of the first shell water molecules behave more like cold water.

Multimedia Tools and Applications, 2019

Steganography, the hiding technique used to secure sensitive data (i.e., images, audio ) while co... more Steganography, the hiding technique used to secure sensitive data (i.e., images, audio ) while communication takes place. In this paper, the message is embedded in color image in frequency domain exploiting Genetic Algorithm (GA) which provides the robustness i.e., the algorithm can withstand against any rigorous testing and brutal attack except destruction of the stego image. The fragmentation of 8-bit binary stream of each color component to 4-bit and applying Genetic Algorithm (GA) to increase the robustness of the scheme. Random Multiple bits are chosen to embed secret message which increases security along with the payload. The use of transform domain, hash function based random pixel and bit selections for data hiding, secrete data encryption and more over use of Genetic Algorithm (GA) for optimization is the novelty of the proposed work. Perspective and meticulous statistical analysis has been done to immune the algorithm from any attack. The algorithm proposed here is tested with benchmark tools like StirMark 4.0, Confusion Matrix (Receiver Operating Curve Characteristic (ROC) curve) along with steganalysis and statistical tools. Visual disturbance and distortion in stego image is also very insignificant here.

Oral cholera vaccines (OCVs) are being increasingly employed, but current killed formulations gen... more Oral cholera vaccines (OCVs) are being increasingly employed, but current killed formulations generally require multiple doses and lack efficacy in young children. We recently developed a new live-attenuated OCV candidate (HaitiV) derived from aVibrio choleraestrain isolated during the 2010 Haiti cholera epidemic. HaitiV exhibited an unexpected probiotic-like activity in infant rabbits, preventing intestinal colonization and disease by wild-typeV. choleraebefore the onset of adaptive immunity. However, it remained unknown whether HaitiV would behave similarly to other OCVs to stimulate adaptive immunity againstV. cholerae.Here, we orally immunized adult germ-free female mice to test HaitiV’s immunogenicity. HaitiV safely and stably colonized vaccinated mice and induced known adaptive immune correlates of cholera protection within 14 days of administration. Pups born to immunized mice were protected against lethal challenges of both homologous and heterologousV. choleraestrains. Cros...

Tectonophysics, 2018

Kopili fault has been experiencing higher seismic and tectonic activity during the recent years. ... more Kopili fault has been experiencing higher seismic and tectonic activity during the recent years. These kind of active tectonics can be inspected by examining coda-wave attenuation and its dependence with frequency. Exploiting single back-scattering model, we have endeavored to measure coda Q and its associated parameters such as frequency dependent factor (n) and attenuation coefficient (γ) covering seven lapse-time windows spanning from 30 to 90 sec and central frequencies 1.5, 3.5, 6, 9 and 12 Hz. The average estimated values of Q C increases with frequency and lapse time window from 114 at frequency 1.5Hz to 1563 at frequency 12Hz for 30sec window length, and from 305 at frequency 1.5Hz to 2135 at frequency 12Hz for 90sec window length. The values of Q 0 and n are also estimated for the entire Kopili fault zone. For this study region, the Q 0 values vary from 62 to 348 and n varies from 0.57 to 1.51 within the frequency range 1.5 to 12 Hz. Furthermore, depth variation of attenuation of this region reveals that there is velocity anomaly at depth 210-220 km as there arises sharp changes in γ and n which are supported by available data, reported by other researcher for this region. Finally, we have tried to separate the intrinsic and scattering attenuation for this area. It is observed that the entire region is dominated by mainly scattering attenuation, but we can see an increase in intrinsic attenuation with depths in two stations namely TZR and BKD. Furthermore, the obtained results are comparable with the available global data.

PLOS Neglected Tropical Diseases, 2015

Background Cholera is endemic in Bangladesh, with outbreaks reported annually. Currently, the maj... more Background Cholera is endemic in Bangladesh, with outbreaks reported annually. Currently, the majority of epidemic cholera reported globally is El Tor biotype Vibrio cholerae isolates of the serogroup O1. However, in Bangladesh, outbreaks attributed to V. cholerae serogroup O139 isolates, which fall within the same phylogenetic lineage as the O1 serogroup isolates, were seen between 1992 and 1993 and in 2002 to 2005. Since then, V. cholerae serogroup O139 has only been sporadically isolated in Bangladesh and is now rarely isolated elsewhere. Methods Here, we present case histories of four cholera patients infected with V. cholerae serogroup O139 in 2013 and 2014 in Bangladesh. We comprehensively typed these isolates using conventional approaches, as well as by whole genome sequencing. Phenotypic typing and PCR confirmed all four isolates belonging to the O139 serogroup. Findings Whole genome sequencing revealed that three of the isolates were phylogenetically closely related to previously sequenced El Tor biotype, pandemic 7, toxigenic V. cholerae O139 isolates originating from Bangladesh and elsewhere. The fourth isolate was a non-toxigenic V.

Environmental Toxicology and Chemistry, 2000

ABSTRACT

mSphere, 2021

Cholera is a severe dehydrating illness of humans caused by Vibrio cholerae serogroup O1 or O139.... more Cholera is a severe dehydrating illness of humans caused by Vibrio cholerae serogroup O1 or O139. Protection against cholera is serogroup specific, and serogroup specificity is defined by O-specific polysaccharide (OSP).

arXiv: Chemical Physics, 2020

Hydrophobic solutes significantly alters water hydrogen bond network. The local alteration of sol... more Hydrophobic solutes significantly alters water hydrogen bond network. The local alteration of solvation struc-tures get reflected in the vibrational spectroscopic signal. Although it is possible to detect this microscopicfeatures by modern infrared spectroscopy, however, bulk phase spectra often comes with formidable challengeof establishing the connection among the experimental spectra to molecular structures. Theoretical spec-troscopy can serve as more powerful tool even where spectroscopic data cannot provide microscopic this http URL the present work, we build a theoretical spectroscopic map based on mixed quantum-classical molecularsimulation approach using methane in water system. The single oscillator level O-H stretch frequency is wellcorrelated with a collective variable solvation energy. We construct the spectroscopic maps for fundamentaltransition frequencies and also the transition dipoles. A bimodal frequency distribution with a blue shiftedpopulation of transition freq...

Geophysical Lab, Department of Physics, Tezpur University, Tezpur-784028, Assam Corresponding aut... more Geophysical Lab, Department of Physics, Tezpur University, Tezpur-784028, Assam Corresponding author: rajib@tezu.ernet.in Kopili fault has been experiencing higher seismic and tectonic activity ([1], [2]) during the recent years. These kinds of active tectonics can be inspected by examining coda-wave attenuation and its dependence with frequency. Here, we report spatial variation of coda attenuation of this region. The obtained results reveal that there is velocity anomaly at depth 210-220 km as there arises sharp changes in attenuation coefficient (γ) and frequency parameter (n) which are supported by available data reported by other researchers for this region.

Vaccine, 2021

BACKGROUND The World Health Organization (WHO) recommends the use of oral cholera vaccines (OCVs)... more BACKGROUND The World Health Organization (WHO) recommends the use of oral cholera vaccines (OCVs) as part of an integrated control program, both in highly endemic settings and during cholera epidemics. The available and internationally recommended WHO-prequalified OCVs (Dukoral, Shanchol, Euvichol) contain multiple heat and formalin-killed V. cholerae strains of Inaba and Ogawa serotypes. MSD Wellcome Trust Hilleman Laboratories Pvt. Ltd. in technical collaboration with University of Gothenburg, Sweden has developed a new single strain OCV, Hillchol. This vaccine consists of formaldehyde-inactivated whole cell El Tor V. cholerae O1 bacteria engineered into the Hikojima serotype for stable expression of both the Ogawa (AB) and Inaba (AC) LPS antigens on the bacterial surface. We evaluated the safety and immunogenicity of this novel and potentially much less expensive OCV in comparison with Shanchol. METHODS We conducted a randomized, non-inferiority, age-descending clinical trial of OCV (Hillchol vs. Shanchol) in the Mirpur area of Dhaka city from July 2016 to May 2017. This study was carried out in three different age cohorts (1-<5, 5-17 and ≥18 years old). Two doses of vaccine were given at 14 days intervals to 560 healthy participants. FINDINGS No serious adverse events were reported. There were no significant differences in the rates of adverse events between the test vaccine (Hillchol) and the comparator (Shanchol) group. Serum vibriocidal antibody responses in all age groups combined were comparable for all the O1 Ogawa (59% vs. 67%; 90% CI of difference: -14.55, -0.84) and Inaba (70% vs. 71%; 90% CI of difference: -7.24, 5.77) serotypes, showing that the Hillchol vaccine was non-inferior to Shanchol. This new vaccine was also non-inferior to Shanchol in the different age strata. CONCLUSION The safety and immunogenicity profile of the new OCV Hillchol is comparable to Shanchol in persons residing in a cholera-endemic setting. ClinicalTrials.gov number: NCT02823899.

International Journal of Geotechnical Earthquake Engineering, 2021

Attenuation study of a province is considered as a basic quantity for seismic hazard assessment. ... more Attenuation study of a province is considered as a basic quantity for seismic hazard assessment. It has already been established that the study of two physical processes, namely the seismic sources and propagation of the waves, is essential for seismic-hazard mapping. Additionally, attenuation plays an important role towards scaling seismic hazard. Accordingly, a computational tool entitled CodaQback is presented. Based on back scattering model, this versatile software is equipped with user-friendly graphical user interface. It also allows quick picking of phases for computing coda attenuation parameter. All outputs after each execution step in CodaQback are efficiently exported step-wise into a separate folder in Excel and text formats. To validate the computing tool, it is tested in real data analysis and there is found to be good matching of computed values with already established ones. It is envisioned that this package will enable user to derive quick and reliable estimation o...

The Journal of Chemical Physics, 2020

Hydrophobic solutes significantly alter the water hydrogen bond network. The local alteration of ... more Hydrophobic solutes significantly alter the water hydrogen bond network. The local alteration of solvation structures gets reflected in the vibrational spectroscopic signal. Although it is possible to detect this microscopic feature by modern infrared spectroscopy, bulk phase spectra often come with a formidable challenge of establishing the connection of experimental spectra to molecular structures. Theoretical spectroscopy can serve as a more powerful tool where spectroscopic data cannot provide the microscopic picture. In the present work, we build a theoretical spectroscopic map based on a hybrid quantum-classical molecular simulation approach using a methane-water system. The single oscillator O-H stretch frequency is well correlated with a collective variable solvation energy. We construct the spectroscopic maps for fundamental transition frequencies and also the transition dipoles. A bimodal frequency distribution with a blue-shifted population of transition frequency illustrates the presence of gas like water molecules in the hydration shell of methane. This observation is further complemented by a shell-wise decomposition of the O-H stretch frequencies. We observe a significant increase in the ordering of the first solvation water molecules, except those which are directly facing the methane molecule. This is manifested in the redshift of the observed transition frequencies. Temperature dependent simulations depict that the water molecules facing the methane molecule behave similarly to the high temperature water, and a few of the first shell water molecules behave more like cold water.

Multimedia Tools and Applications, 2019

Steganography, the hiding technique used to secure sensitive data (i.e., images, audio ) while co... more Steganography, the hiding technique used to secure sensitive data (i.e., images, audio ) while communication takes place. In this paper, the message is embedded in color image in frequency domain exploiting Genetic Algorithm (GA) which provides the robustness i.e., the algorithm can withstand against any rigorous testing and brutal attack except destruction of the stego image. The fragmentation of 8-bit binary stream of each color component to 4-bit and applying Genetic Algorithm (GA) to increase the robustness of the scheme. Random Multiple bits are chosen to embed secret message which increases security along with the payload. The use of transform domain, hash function based random pixel and bit selections for data hiding, secrete data encryption and more over use of Genetic Algorithm (GA) for optimization is the novelty of the proposed work. Perspective and meticulous statistical analysis has been done to immune the algorithm from any attack. The algorithm proposed here is tested with benchmark tools like StirMark 4.0, Confusion Matrix (Receiver Operating Curve Characteristic (ROC) curve) along with steganalysis and statistical tools. Visual disturbance and distortion in stego image is also very insignificant here.

Oral cholera vaccines (OCVs) are being increasingly employed, but current killed formulations gen... more Oral cholera vaccines (OCVs) are being increasingly employed, but current killed formulations generally require multiple doses and lack efficacy in young children. We recently developed a new live-attenuated OCV candidate (HaitiV) derived from aVibrio choleraestrain isolated during the 2010 Haiti cholera epidemic. HaitiV exhibited an unexpected probiotic-like activity in infant rabbits, preventing intestinal colonization and disease by wild-typeV. choleraebefore the onset of adaptive immunity. However, it remained unknown whether HaitiV would behave similarly to other OCVs to stimulate adaptive immunity againstV. cholerae.Here, we orally immunized adult germ-free female mice to test HaitiV’s immunogenicity. HaitiV safely and stably colonized vaccinated mice and induced known adaptive immune correlates of cholera protection within 14 days of administration. Pups born to immunized mice were protected against lethal challenges of both homologous and heterologousV. choleraestrains. Cros...

Tectonophysics, 2018

Kopili fault has been experiencing higher seismic and tectonic activity during the recent years. ... more Kopili fault has been experiencing higher seismic and tectonic activity during the recent years. These kind of active tectonics can be inspected by examining coda-wave attenuation and its dependence with frequency. Exploiting single back-scattering model, we have endeavored to measure coda Q and its associated parameters such as frequency dependent factor (n) and attenuation coefficient (γ) covering seven lapse-time windows spanning from 30 to 90 sec and central frequencies 1.5, 3.5, 6, 9 and 12 Hz. The average estimated values of Q C increases with frequency and lapse time window from 114 at frequency 1.5Hz to 1563 at frequency 12Hz for 30sec window length, and from 305 at frequency 1.5Hz to 2135 at frequency 12Hz for 90sec window length. The values of Q 0 and n are also estimated for the entire Kopili fault zone. For this study region, the Q 0 values vary from 62 to 348 and n varies from 0.57 to 1.51 within the frequency range 1.5 to 12 Hz. Furthermore, depth variation of attenuation of this region reveals that there is velocity anomaly at depth 210-220 km as there arises sharp changes in γ and n which are supported by available data, reported by other researcher for this region. Finally, we have tried to separate the intrinsic and scattering attenuation for this area. It is observed that the entire region is dominated by mainly scattering attenuation, but we can see an increase in intrinsic attenuation with depths in two stations namely TZR and BKD. Furthermore, the obtained results are comparable with the available global data.

PLOS Neglected Tropical Diseases, 2015

Background Cholera is endemic in Bangladesh, with outbreaks reported annually. Currently, the maj... more Background Cholera is endemic in Bangladesh, with outbreaks reported annually. Currently, the majority of epidemic cholera reported globally is El Tor biotype Vibrio cholerae isolates of the serogroup O1. However, in Bangladesh, outbreaks attributed to V. cholerae serogroup O139 isolates, which fall within the same phylogenetic lineage as the O1 serogroup isolates, were seen between 1992 and 1993 and in 2002 to 2005. Since then, V. cholerae serogroup O139 has only been sporadically isolated in Bangladesh and is now rarely isolated elsewhere. Methods Here, we present case histories of four cholera patients infected with V. cholerae serogroup O139 in 2013 and 2014 in Bangladesh. We comprehensively typed these isolates using conventional approaches, as well as by whole genome sequencing. Phenotypic typing and PCR confirmed all four isolates belonging to the O139 serogroup. Findings Whole genome sequencing revealed that three of the isolates were phylogenetically closely related to previously sequenced El Tor biotype, pandemic 7, toxigenic V. cholerae O139 isolates originating from Bangladesh and elsewhere. The fourth isolate was a non-toxigenic V.

Environmental Toxicology and Chemistry, 2000

ABSTRACT