Browsing by Author "D. Chattopadhyay"

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Antiovarian antibody in premature ovarian failure.
(1999) D. Chattopadhyay; M.R. Sen; P. Katiyar; L.K. Pandey
Premature ovarian failure is a syndrome consisting of primary or secondary amenorrhoea, hypergonodotropiremia and hypoestrogenemia in women under the age of 40. An autoimmune mechanism was suggested as possible etiology when Vallolton and Forbes in 1966-67 found antibodies to the cytoplasm of rabbit ova in 29 of 232 tested sera. Immune mechanism in the pathogenesis of premature ovarian failure (POF) is suggested by association of autoimmune phenomenon with POF in some cases and demonstration of circulating antibodies to ovary in serum samples from women with POF. The incidence of presence of antiovarian antibody of POF patients has been reported earlier. Evidence of autoimmunity is present in 18-92% of patients with POF. In the present study we have studied 18 cases of POF without any overt manifestation of autoimmune disorder but the antiovarian antibody was detected, with the idea that this autoantibody might be the cause of ovarian dysfunction which is evident in POF. Presence of antiovarian antibody in 16.67% cases with POF in our study that ovarian antibodies may play a role in or reflect an autoimmune process responsible for the development of POF.
Fusion of O 16 + Ho 165 at deep sub-barrier energies
(American Physical Society, 2021) Saikat Bhattacharjee; A. Mukherjee; Ashish Gupta; Rajkumar Santra; D. Chattopadhyay; N. Deshmukh; Sangeeta Dhuri; Shilpi Gupta; V.V. Parkar; S.K. Pandit; K. Ramachandran; K. Mahata; A. Shrivastava; Rebecca Pachuau; S. Rathi
Fusion cross sections have been measured for the asymmetric system O16+Ho165 at energies near and deep below the Coulomb barrier with an aim to investigate the occurrence of fusion hindrance for the system. Cross sections down to ≈700 nb have been measured using the off-beam γ-ray technique. The fusion cross sections have been compared with the coupled channel calculations. The energy onset of fusion hindrance appears to occur at Ec.m.=57±0.85 MeV, where a deviation in the slope of the experimental logarithmic derivative compared to that of coupled channel calculations has been observed. This is in agreement with the value obtained from the touching point configuration of the adiabatic model. © 2021 American Physical Society.