13 research outputs found
Whole-Genome Sequence of Drug-Resistant Mycobacterium tuberculosis Strain S7, Isolated from a Patient with Pulmonary Tuberculosis
Over the past decades, drug-resistant Mycobacterium tuberculosis strains have presented a significant challenge, with inadequate diagnosis of tuberculosis (TB) cases. Here, we report the draft whole-genome sequence of drug-resistant M. tuberculosis strain S7, which was isolated from a patient from Tripura, India, who was diagnosed with pulmonary TB
A novel procedure for the synthesis of NH3 incorporated VPO phases
It has been observed that as a function of a time delay introduced between the onset of the reduction of V2O5
with hydroxylamine hydrochloride and the addition of phosphoric acid, in the aqueous route preparation of the
catalytically important VOHPO4?0.5H2O phase, a series of NH3 incorporated phases are obtained. Up to delay
times of 3 min the crystalline VOHPO4?0.5H2O phase is obtained whereas a weakly crystalline hemihydrate is
formed at a delay time of 4 min. Longer delay times result in X-ray amorphous phases until at delay time of
10 min and above a new crystalline phase containing mixed-valent vanadium emerges. All the phases obtained
with delay times of 4 min and above have NH3 incorporated into them. The weakly crystalline
VOHPO4?0.5H2O phase as well as the X-ray amorphous phases undergo transformation to a crystalline
vanadyl pyrophosphate phase on calcination at 723 K in spite of having NH3 incorporated into them. The
in-situ generation of NH3 during the preparation procedure is a hitherto unreported aspect of VPO chemistry
and provides a convenient method for the preparation of novel NH3 incorporated VPO phases which could
have strong potential as catalysts for alkane oxidation as well as for ammoxidation reactions
Long chain alkyl amine templated synthesis of a mesostructured lamellar vanadium phosphate phase
n-Hexadecylamine (HDA) has been used as a template to
synthesize a mesolamellar vanadium phosphate (VPO)
phase. FTIR studies indicate covalent interaction of the
amine head with the vanadyl groups of the VPO matrix,
in contrast to the other reported syntheses of mesostructured
VPO phases which involve ionic interaction
between a cationic surfactant and the inorganic matrix.
XRD, TEM and solid state 13C MAS NMR studies show
that the incorporated HDA induces the formation of a
mesolamellar phase with a basal spacing of 44.5 A°
. On
ageing however, a restructuring of the incorporated
HDA is observed resulting in a curvature of the inorganic
layers and a decrease of the basal spacing to
38.04
Metal ion incorporated VPO phases as novel catalysts
Vanadium phosphates function as catalysts for the selective oxidation of hydrocarbons with their activity being strongly
dependent on their structure. Consequently, attempts have been made to synthesise novel phases in the VPO system through metal
ion incorporation and evaluate the catalytic activity of these phases. It is shown that the incorporation of palladium or platinum
leads to novel phases which vary according to the method of syntheses. The incorporated metal ions are catalytically active both for
oxidation and reduction reactions with the activity varying according to the mode of incorporation. These phases constitute a novel
class of compounds in which oxidation centres are substituted or dispersed within a VPO oxidation catalyst
Novel platinum incorporated vanadium phosphates and their catalytic activity
Platinum has been incorporated into the layered vanadyl hydrogen phosphate VOHPO4·0.5H2O in different ways depending
upon the medium of its preparation. The phase obtained by the introduction of platinum during the synthesis of
VOHPO4·0.5H2O in aqueous medium is a new crystalline phase with mixed-valent vanadium containing Pt2+ species. This
phase forms a novel hydrogen insertion compound involving hydrogen spillover from the incorporated platinum onto the
VPO matrix. On the other hand, the incorporation of platinum during the synthesis of the hemihydrate in organic medium
gives rise to a phase containing both metallic platinum and an amorphous Pt2+ containing VPO phase. Both these platinum
incorporated phases have been found to be active catalysts for reduction and oxidation reactions such as the hydrogenation of
nitrobenzene and the oxidation of tetrahydrofuran with the activity varying quite markedly with the mode of incorporation.
© 2002 Elsevier Science B.V. All rights reserved
Mesolamellar VPO phases obtained by incorporating long chain alkyl amine surfactants into the layeredvanadium phosphate dihydrate phase
A series of mesolamellar VPO-amine phases have been obtained by intercalation of alkyl amines of differing alkyl chain lengths
into the catalytically important VOPO4 Æ2H2O phase. It is demonstrated that there is considerable variation in the conformation of
the incorporated alkyl amines, which progressively assume a more disordered gauche conformation in their internal methylene
groups with decreasing chain length. This finding contradicts the assumption made by previous workers that the alkyl amines incorporated
into VPO-amine nanocomposites have fully stretched all trans conformations. From the present study, the observation that
the basal spacing in long chain amine intercalated mesostructured VPO phases is smaller than that expected from the fully stretched
amine molecule can be attributed to the shortening of the incorporated amine molecule due to the gauche conformation of the internal
methylene groups. This is in contrast to the postulation of tilted configurations of fully stretched all trans amine molecules, made
by earlier workers. It is also observed that the alkyl amine to vanadium ratio increases with increasing alkyl tail length of the incorporated
amine, which is consistent with our observation of more ordering in the longer chain amines leading to better packing.
Keywords: Vanadium (V) orthophosphate; Alkyl amine surfactant; Intercalation; Mesostructured VPO phases; Conformational heterogeneit
Diagnostic evaluation of pancytopenia - a prospective institutional study in North-East India
Introduction: Pancytopenia, the simultaneous reduction of all the three formed elements of blood, is diverse in its etiology. Full clinico-hematopathological work up is crucial in each case. This study was undertaken with the objectives of identifying the causes of pancytopenia and its phenotypic characteristics in relation to age, sex, ethnicity and socio- economic status.
Methods: Ninety two cases of pancytopenia studied here were diagnosed by complete hemogram study in automated hematology analyzer. Peripheral blood smear studies were carried out. All cases were subjected to bone marrow aspiration/ imprint smear cytology and trephine biopsy study. Hypoplastic anemia cases were investigated for paroxysmal nocturnal hemoglobinuria (PNH) with flow cytometric analysis of red blood cells treated with CD55 and CD59 antibodies.
Results: Fifty eight percent of cases were males and mean age was 52 years. Children constituted 16% of patients. Thirty-seven percent of cases belonged to tribal community. Around 70% belonged to low socio-economic status. Causes of pancytopenia detected were primary hematological malignancies (Total 39.2 % with acute leukaemia 35.9%, lymphoma 2.2% and multiple myeloma 1.1%), hypoplastic anaemia (28.3%), myelodysplastic syndrome (MDS) (21.7%), megaloblastic Anemia (6.5%) and hypersplenism (4.3%). No PNH clone was detected amongst hypoplastic anemia cases.
Conclusion: It is concluded that pancytopenia often is the manifestation of serious disease-processes and the commonest cause, in our population of this North-Eastern state of Tripura, being acute leukemia. Bone marrow cytology and biopsy study must be performed in all cases of pancytopenia to find out the cause in order to institute an early treatment