Background There is paucity of data regarding duration of fecal excretion and viremia on sequenti... more Background There is paucity of data regarding duration of fecal excretion and viremia on sequential samples from individual patients and its correlation with serum transaminases and antibody responses in patients with acute hepatitis E. This prospective study was undertaken at a tertiary care center in Northern India over 15 months. Only those patients of sporadic acute hepatitis E who were in their first week of illness and followed up weekly for liver function tests, IgM anti HEV antibody and HEV RNA in sera and stool were included. HEV RNA was done by RT - nPCR using two pairs of primers from RdRp region of ORF 1 of the HEV genome. Results Over a period of 15 months 60 patients met the inclusion criterion and were enrolled for the final analysis. The mean age of the patients was 29.2 ± 8.92 years, there were 39 males. The positivity of IgM anti HEV was 80% at diagnosis and 18.3% at 7th week, HEV RNA 85% at diagnosis and 6.6% at 7th week and fecal RNA 70% at the time of diagnosis and 20% at 4th week. The maximum duration of viremia detected was 42 days and fecal viral shedding was 28 days after the onset of illness. Conclusion Present study reported HEV RNA positivity in sera after normalization of transaminases. Fecal shedding was not seen beyond normalization of transaminases. However, viremia lasted beyond normalization of transaminases suggesting that liver injury is independent of viral replication.
Abstract: Present study is an evaluation of the persistence of IgM anti HEV in patients with acut... more Abstract: Present study is an evaluation of the persistence of IgM anti HEV in patients with acute sporadic hepatitis E virus infection. This was a prospective study carried out a tertiary care centre. The diagnosis of acute hepatitis E was based on clinical and biochemical ...
We have fabricated an organic light emitting diode using poly(n-butylphenylsilane) which has an e... more We have fabricated an organic light emitting diode using poly(n-butylphenylsilane) which has an emission in deep ultraviolet at at room temperature. The device structure used is glass/indium tin oxide/poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate)/polysilane (emitting ...
Polysilanes are potential candidates for active materials in light emitting diodes because of pos... more Polysilanes are potential candidates for active materials in light emitting diodes because of possible emission in the near-ultraviolet to blue region. Unfortunately, they degrade rapidly upon exposure to light because of scission of sigma bonds. Relative stability of four polysilanes, for example, poly(di-n-butylsilane) (PDBS), poly(di-n-hexylsilane) (PDHS), poly(methylphenylsilane) (PMPS), and poly[bis(p-butylphenyl)silane] (PBPS), which have been reported as active materials in light emitting diodes, have been investigated theoretically through semiempirical (AM1) and ab initio (HF/6-31g) methods and density functional theory using B3LYP parametrization. The AM1 level of calculation predicts the absorption maxima reasonably, but it fails to explain the relative stabilities of the four polysilanes in the excited state. However, calculations based on configuration interaction with single excitation and time-dependent density functional theory suggest additional stabilization in the excited states through intersystem crossing to triplets for PMPS and PBPS, consistent with the experimental observation. In contrast, no such stabilization is predicted for PDBS and PDHS. Furthermore, the existence of a stable triplet state in PMPS may also explain the visible emission observed experimentally in PMPS.
While most organic light emitting diodes are designed to emit in the visible region, we report a ... more While most organic light emitting diodes are designed to emit in the visible region, we report a series of polysilane based diodes for developing ultraviolet emitters at room temperature. These reported devices can also be controlled to simultaneously emit both ultraviolet and visible light, very close to the equienergy white point [Commission Internationale de l'Eclairage coordinate (0.33,0.33)]. Furthermore, the color coordinate of the visible emission is independent of the applied voltage. Therefore, the reported polysilane organic light emitting diodes can also be used as a white light source in which the ultraviolet emission from the same device provides an opportunity to modulate the color. While the origin of ultraviolet emission in electroluminescence is ascribed to an excitonic emission from the σ-σ* transition, consistent with its presence in the photoluminescence spectrum, we assign visible emission to defects states, based on degradation studies of the electroluminescent device.
Theoretical investigations to determine the stability among different polysilanes have been attem... more Theoretical investigations to determine the stability among different polysilanes have been attempted. Semiempirical (AM1) and ab initio calculations at Hartree Fock (HF)/321g* level have been performed for four polymers namely poly(di-n-butylsilane) (PDBS), poly(di-n-...
The photodegradation of a copolymer based on diphenyl and methylphenyl polysilane has been invest... more The photodegradation of a copolymer based on diphenyl and methylphenyl polysilane has been investigated by measuring the changes occurring in photoluminescence (PL) and absorption in solution and film form. In the solution, the degradation mechanism is photoscission of ...
Background There is paucity of data regarding duration of fecal excretion and viremia on sequenti... more Background There is paucity of data regarding duration of fecal excretion and viremia on sequential samples from individual patients and its correlation with serum transaminases and antibody responses in patients with acute hepatitis E. This prospective study was undertaken at a tertiary care center in Northern India over 15 months. Only those patients of sporadic acute hepatitis E who were in their first week of illness and followed up weekly for liver function tests, IgM anti HEV antibody and HEV RNA in sera and stool were included. HEV RNA was done by RT - nPCR using two pairs of primers from RdRp region of ORF 1 of the HEV genome. Results Over a period of 15 months 60 patients met the inclusion criterion and were enrolled for the final analysis. The mean age of the patients was 29.2 ± 8.92 years, there were 39 males. The positivity of IgM anti HEV was 80% at diagnosis and 18.3% at 7th week, HEV RNA 85% at diagnosis and 6.6% at 7th week and fecal RNA 70% at the time of diagnosis and 20% at 4th week. The maximum duration of viremia detected was 42 days and fecal viral shedding was 28 days after the onset of illness. Conclusion Present study reported HEV RNA positivity in sera after normalization of transaminases. Fecal shedding was not seen beyond normalization of transaminases. However, viremia lasted beyond normalization of transaminases suggesting that liver injury is independent of viral replication.
Abstract: Present study is an evaluation of the persistence of IgM anti HEV in patients with acut... more Abstract: Present study is an evaluation of the persistence of IgM anti HEV in patients with acute sporadic hepatitis E virus infection. This was a prospective study carried out a tertiary care centre. The diagnosis of acute hepatitis E was based on clinical and biochemical ...
We have fabricated an organic light emitting diode using poly(n-butylphenylsilane) which has an e... more We have fabricated an organic light emitting diode using poly(n-butylphenylsilane) which has an emission in deep ultraviolet at at room temperature. The device structure used is glass/indium tin oxide/poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate)/polysilane (emitting ...
Polysilanes are potential candidates for active materials in light emitting diodes because of pos... more Polysilanes are potential candidates for active materials in light emitting diodes because of possible emission in the near-ultraviolet to blue region. Unfortunately, they degrade rapidly upon exposure to light because of scission of sigma bonds. Relative stability of four polysilanes, for example, poly(di-n-butylsilane) (PDBS), poly(di-n-hexylsilane) (PDHS), poly(methylphenylsilane) (PMPS), and poly[bis(p-butylphenyl)silane] (PBPS), which have been reported as active materials in light emitting diodes, have been investigated theoretically through semiempirical (AM1) and ab initio (HF/6-31g) methods and density functional theory using B3LYP parametrization. The AM1 level of calculation predicts the absorption maxima reasonably, but it fails to explain the relative stabilities of the four polysilanes in the excited state. However, calculations based on configuration interaction with single excitation and time-dependent density functional theory suggest additional stabilization in the excited states through intersystem crossing to triplets for PMPS and PBPS, consistent with the experimental observation. In contrast, no such stabilization is predicted for PDBS and PDHS. Furthermore, the existence of a stable triplet state in PMPS may also explain the visible emission observed experimentally in PMPS.
While most organic light emitting diodes are designed to emit in the visible region, we report a ... more While most organic light emitting diodes are designed to emit in the visible region, we report a series of polysilane based diodes for developing ultraviolet emitters at room temperature. These reported devices can also be controlled to simultaneously emit both ultraviolet and visible light, very close to the equienergy white point [Commission Internationale de l'Eclairage coordinate (0.33,0.33)]. Furthermore, the color coordinate of the visible emission is independent of the applied voltage. Therefore, the reported polysilane organic light emitting diodes can also be used as a white light source in which the ultraviolet emission from the same device provides an opportunity to modulate the color. While the origin of ultraviolet emission in electroluminescence is ascribed to an excitonic emission from the σ-σ* transition, consistent with its presence in the photoluminescence spectrum, we assign visible emission to defects states, based on degradation studies of the electroluminescent device.
Theoretical investigations to determine the stability among different polysilanes have been attem... more Theoretical investigations to determine the stability among different polysilanes have been attempted. Semiempirical (AM1) and ab initio calculations at Hartree Fock (HF)/321g* level have been performed for four polymers namely poly(di-n-butylsilane) (PDBS), poly(di-n-...
The photodegradation of a copolymer based on diphenyl and methylphenyl polysilane has been invest... more The photodegradation of a copolymer based on diphenyl and methylphenyl polysilane has been investigated by measuring the changes occurring in photoluminescence (PL) and absorption in solution and film form. In the solution, the degradation mechanism is photoscission of ...
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Papers by Asha Sharma