Pratik Kumar Singh | Universidad Privada del Norte (original) (raw)

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Papers by Pratik Kumar Singh

Advances in Science, Technology and Engineering Systems Journal

With the current emerging development pattern in Malaysia, E-Government has been unveiled by the ... more With the current emerging development pattern in Malaysia, E-Government has been unveiled by the Malaysian Government to be one of the multimedia super corridor flagship applications to implement digital technology to improve government operations. Eprocurement was originally utilized by businesses to minimize turnaround times and prices, but recently it was often used as a platform for sustainable procurement. However, there have been few attempts to investigate E-procurement technology in Malaysia concerning sustainable procurement. Also, there is no consistent and reliable framework of Eprocurement technology for sustainable procurement practices. The focal area of this research is ISO 14001 accredited firms in Malaysia, the population of these organizations is 55, sample size (N)=162 respondents including procurement managers, executives and staff which are involved directly or indirectly in the process of procuring products and services. This study is conceptual and aims to explore how the adoption of E-procurement technologies influence sustainable procurement practices within ISO 14001 accredited firms in Malaysia.

Biochimica et Biophysica Acta (BBA) - Biomembranes, 2015

The role of the outer-membrane channel from a mycolic acid containing Gram-positive bacteria Noca... more The role of the outer-membrane channel from a mycolic acid containing Gram-positive bacteria Nocardia farcinica, which forms a hydrophilic pathway across the cell wall, was characterized. Single channel electrophysiology measurements and liposome swelling assays revealed the permeation of hydrophilic solutes including sugars, amino acids and antibiotics. The cation selective N. farcinica channel exhibited strong interaction with the positively charged antibiotics; amikacin and kanamycin, and surprisingly also with the negatively charged ertapenem. Voltage dependent kinetics of amikacin and kanamycin interactions were studied to distinguish binding from translocation. Moreover, the importance of charged residues inside the channel was investigated using mutational studies that revealed rate limiting interactions during the permeation.

Virology, 2009

Viruses-like particles (VLPs) are frequently being used as platforms for polyvalent display of fo... more Viruses-like particles (VLPs) are frequently being used as platforms for polyvalent display of foreign epitopes of interest on their capsid surface to improve their presentation enhancing the antigenicity and host immune response. In the present study, we used the VLPs of Tomato bushy stunt virus (TBSV), an icosahedral plant virus, as a platform to display 180 copies of 16 amino acid epitopes of ricin toxin fused to the C-terminal end of a modified TBSV capsid protein (NΔ52). Expression of the chimeric recombinant protein in insect cells resulted in spontaneous assembly of VLPs displaying the ricin epitope. Cryo-electron microscopy and image reconstruction of the chimeric VLPs at 22 Å resolution revealed the locations and orientation of the ricin epitope exposed on the TBSV capsid surface. Furthermore, injection of chimeric VLPs into mice generated antisera that detected the native ricin toxin. The ease of fusing of short peptides of 15-20 residues and their ability to form two kinds (T = 1, T = 3) of bio-nanoparticles that result in the display of 60 or 180 copies of less constrained and highly exposed antigenic epitopes makes TBSV an attractive and versatile display platform for vaccine design.

Viruses and Nanotechnology, 2009

Advances in genetics, proteomics and cellular and molecular biology are being integrated and tran... more Advances in genetics, proteomics and cellular and molecular biology are being integrated and translated to develop effective methods for the prevention and control of cancer. One such combined effort is to create multifunctional nanodevices that will specifically recognize tumors and thus enable early diagnosis and provide targeted treatment of this disease. Viral particles are being considered for this purpose since they are inherently nanostructures with well-defined geometry and uniformity, ideal for displaying molecules in a precise spatial distribution at the nanoscale level and subject to greater structural control. Viruses are presumably the most efficient nanocontainer for cellular delivery as they have naturally evolved mechanisms for binding to and entering cells. Virus-based systems typically require genetic or chemical modification of their surfaces to achieve tumor-specific interactions. Interestingly, canine parvovirus (CPV) has a natural affinity for transferrin receptors (TfRs) (both of canine and human origin) and this property could be harnessed as TfRs are overexpressed by a variety of human tumor cells. Since TfR recognition relies on the CPV capsid protein, we envisioned the use of virus or its shells as tumor targeting agents. We observed that derivatization of CPV virus-like particles (VLPs) with dye molecules did not impair particle binding to TfRs or internalization into human tumor cells. Thus CPV-based VLPs with a natural tropism for TfRs hold great promise in the development of novel nanomaterial for delivery of a therapeutic and/or genetic cargo.

Advanced Drug Delivery Reviews, 2006

Non-invasive imaging holds great promise for the early detection and treatment of human disease. ... more Non-invasive imaging holds great promise for the early detection and treatment of human disease. The ability to both detect and follow disease processes or anatomical defects without biopsy, surgery, or other invasive techniques should lead to lower costs and higher quality of life. The use of "smart" nanoparticles, that combine multiple functions of targeting, imaging, and drug delivery, have tremendous potential to increase the sensitivity and specificity of therapies. These will facilitate early detection and reduce adverse side effects of treatment. There are many different classes of nanoparticles in development including dendrimers, liposomes, paramagnetic nanoparticles, and quantum dots, to name just a few. Here we focus on virus-based nanoparticles (VNPs) as platforms for the development of tissue-specific targeting and imaging agents in vivo.

ACS Nano, 2012

We investigated translocation of cationic peptides through nanochannels derived from the Gram-pos... more We investigated translocation of cationic peptides through nanochannels derived from the Gram-positive bacterium Nocardia farcinica at the single-molecule level. The two subunits NfpA and NfpB form a hetero-oligomeric cation selective channel. On the basis of amino acid comparison we performed homology modeling and obtained a channel structurally related to MspA of Mycobacterium smegmatis. The quantitative single-molecule measurements provide an insight into transport processes of solutes through nanochannels. High-resolution ion conductance measurements in the presence of peptides of different charge and length revealed the kinetics of peptide binding. The observed asymmetry in peptide binding kinetics indicated a unidirectional channel insertion in the lipid bilayer. In the case of cationic peptides, the external voltage acts as a driving force that promotes the interaction of the peptide with the channel surface. At low voltage, the peptide just binds to the channel, whereas at higher voltage, the force is strong enough to pull the peptide across the channel. This allows distinguishing quantitatively between peptide binding and translocation through the channel.

Advances in Science, Technology and Engineering Systems Journal

With the current emerging development pattern in Malaysia, E-Government has been unveiled by the ... more With the current emerging development pattern in Malaysia, E-Government has been unveiled by the Malaysian Government to be one of the multimedia super corridor flagship applications to implement digital technology to improve government operations. Eprocurement was originally utilized by businesses to minimize turnaround times and prices, but recently it was often used as a platform for sustainable procurement. However, there have been few attempts to investigate E-procurement technology in Malaysia concerning sustainable procurement. Also, there is no consistent and reliable framework of Eprocurement technology for sustainable procurement practices. The focal area of this research is ISO 14001 accredited firms in Malaysia, the population of these organizations is 55, sample size (N)=162 respondents including procurement managers, executives and staff which are involved directly or indirectly in the process of procuring products and services. This study is conceptual and aims to explore how the adoption of E-procurement technologies influence sustainable procurement practices within ISO 14001 accredited firms in Malaysia.

Biochimica et Biophysica Acta (BBA) - Biomembranes, 2015

The role of the outer-membrane channel from a mycolic acid containing Gram-positive bacteria Noca... more The role of the outer-membrane channel from a mycolic acid containing Gram-positive bacteria Nocardia farcinica, which forms a hydrophilic pathway across the cell wall, was characterized. Single channel electrophysiology measurements and liposome swelling assays revealed the permeation of hydrophilic solutes including sugars, amino acids and antibiotics. The cation selective N. farcinica channel exhibited strong interaction with the positively charged antibiotics; amikacin and kanamycin, and surprisingly also with the negatively charged ertapenem. Voltage dependent kinetics of amikacin and kanamycin interactions were studied to distinguish binding from translocation. Moreover, the importance of charged residues inside the channel was investigated using mutational studies that revealed rate limiting interactions during the permeation.

Virology, 2009

Viruses-like particles (VLPs) are frequently being used as platforms for polyvalent display of fo... more Viruses-like particles (VLPs) are frequently being used as platforms for polyvalent display of foreign epitopes of interest on their capsid surface to improve their presentation enhancing the antigenicity and host immune response. In the present study, we used the VLPs of Tomato bushy stunt virus (TBSV), an icosahedral plant virus, as a platform to display 180 copies of 16 amino acid epitopes of ricin toxin fused to the C-terminal end of a modified TBSV capsid protein (NΔ52). Expression of the chimeric recombinant protein in insect cells resulted in spontaneous assembly of VLPs displaying the ricin epitope. Cryo-electron microscopy and image reconstruction of the chimeric VLPs at 22 Å resolution revealed the locations and orientation of the ricin epitope exposed on the TBSV capsid surface. Furthermore, injection of chimeric VLPs into mice generated antisera that detected the native ricin toxin. The ease of fusing of short peptides of 15-20 residues and their ability to form two kinds (T = 1, T = 3) of bio-nanoparticles that result in the display of 60 or 180 copies of less constrained and highly exposed antigenic epitopes makes TBSV an attractive and versatile display platform for vaccine design.

Viruses and Nanotechnology, 2009

Advances in genetics, proteomics and cellular and molecular biology are being integrated and tran... more Advances in genetics, proteomics and cellular and molecular biology are being integrated and translated to develop effective methods for the prevention and control of cancer. One such combined effort is to create multifunctional nanodevices that will specifically recognize tumors and thus enable early diagnosis and provide targeted treatment of this disease. Viral particles are being considered for this purpose since they are inherently nanostructures with well-defined geometry and uniformity, ideal for displaying molecules in a precise spatial distribution at the nanoscale level and subject to greater structural control. Viruses are presumably the most efficient nanocontainer for cellular delivery as they have naturally evolved mechanisms for binding to and entering cells. Virus-based systems typically require genetic or chemical modification of their surfaces to achieve tumor-specific interactions. Interestingly, canine parvovirus (CPV) has a natural affinity for transferrin receptors (TfRs) (both of canine and human origin) and this property could be harnessed as TfRs are overexpressed by a variety of human tumor cells. Since TfR recognition relies on the CPV capsid protein, we envisioned the use of virus or its shells as tumor targeting agents. We observed that derivatization of CPV virus-like particles (VLPs) with dye molecules did not impair particle binding to TfRs or internalization into human tumor cells. Thus CPV-based VLPs with a natural tropism for TfRs hold great promise in the development of novel nanomaterial for delivery of a therapeutic and/or genetic cargo.

Advanced Drug Delivery Reviews, 2006

Non-invasive imaging holds great promise for the early detection and treatment of human disease. ... more Non-invasive imaging holds great promise for the early detection and treatment of human disease. The ability to both detect and follow disease processes or anatomical defects without biopsy, surgery, or other invasive techniques should lead to lower costs and higher quality of life. The use of "smart" nanoparticles, that combine multiple functions of targeting, imaging, and drug delivery, have tremendous potential to increase the sensitivity and specificity of therapies. These will facilitate early detection and reduce adverse side effects of treatment. There are many different classes of nanoparticles in development including dendrimers, liposomes, paramagnetic nanoparticles, and quantum dots, to name just a few. Here we focus on virus-based nanoparticles (VNPs) as platforms for the development of tissue-specific targeting and imaging agents in vivo.

ACS Nano, 2012

We investigated translocation of cationic peptides through nanochannels derived from the Gram-pos... more We investigated translocation of cationic peptides through nanochannels derived from the Gram-positive bacterium Nocardia farcinica at the single-molecule level. The two subunits NfpA and NfpB form a hetero-oligomeric cation selective channel. On the basis of amino acid comparison we performed homology modeling and obtained a channel structurally related to MspA of Mycobacterium smegmatis. The quantitative single-molecule measurements provide an insight into transport processes of solutes through nanochannels. High-resolution ion conductance measurements in the presence of peptides of different charge and length revealed the kinetics of peptide binding. The observed asymmetry in peptide binding kinetics indicated a unidirectional channel insertion in the lipid bilayer. In the case of cationic peptides, the external voltage acts as a driving force that promotes the interaction of the peptide with the channel surface. At low voltage, the peptide just binds to the channel, whereas at higher voltage, the force is strong enough to pull the peptide across the channel. This allows distinguishing quantitatively between peptide binding and translocation through the channel.