Delhi, India
Delhi, India

The University of Delhi is a public central university located in Delhi, India. It is the premier university of the country and is known for its high standards in teaching and research, as well as the eminent scholars it attracts to its faculty.It was established in 1922 as a unitary, teaching and residential university by an Act of the then Central Legislative Assembly. The President of India is the Visitor, the Vice President is the Chancellor and the Chief Justice of the Supreme Court of India is the Pro-Chancellor of the University. Ever since its inception, a strong commitment to excellence in teaching and research has made the University of Delhi a role-model and path-setter for other universities in the country. Its rich academic tradition has always attracted the most talented students who later on go on to make important contributions to their society. Wikipedia.

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Deb M.,University of Delhi
Ore Geology Reviews | Year: 2014

In this overview, the Precambrian metallogeny in the Indian shield has been summarized in the backdrop of the evolution of different crustal domains and their linkages to the geodynamic history of the shield. The northern cratonic block (NCB) of the Indian shield is constituted by the Bundelkhand massif (BM), Aravalli-Delhi orogenic belt (ADOB), Shillong plateau and the Himalayan Proterozoic belts and is separated from the larger southern cratonic block (SCB) comprising the Singhbhum craton (SC), Bastar craton (BC), Dharwar craton (DC, including WDC, EDC as well as the Southern Granulite Terrain (SGT)) and the Eastern Ghat mobile belt (EGMB) by the ENE-WSW-trending Central Indian Tectonic Zone (CITZ). These two cratonic blocks are constituted by a few distinct crustal domains: the Archean cratonic nuclei and the Gneissic complexes with the granulitic or granite-greenstone terranes and the Proterozoic mobile belts and intra-cratonic basins, along with the anorogenic volcano-plutonic complexes and mafic dyke swarms. Within the various litho-tectonic domains of the Indian shield are concentrated vast resources of iron, manganese and aluminum and notable resources of chromium, copper, lead, zinc and uranium. There are also significant reserves of gold and tungsten as well as rare concentration of tin and platinoid metals. Titanium along with thorium and other REE are now largely concentrated in coastal placer deposits. Out of these, the Al and REE (including Th and Ti) resources, although derived from Precambrian rocks, are the products of metallogenic processes in the Mesozoic and Cenozoic eras, and have been left out of the discussion.Metallogeny in the Indian shield spanned over a long period of 2.9. Gyr (~. 3.6 to 0.7. Ga) during five specific epochs. The earliest mineralization (+. 3.5. Ga) is recorded from a BIF in SC. Paleo- to Mesoarchean (~. 3.3 to 3.1. Ga) saw the formation of Ti-V-Fe, Cr. +. PGM, Au, Cu and Fe (BIF) in WDC and SC respectively. Intense and economically important metallogeny took place in Neoarchean (2.7 to 2.5. Ga) in SC, BC and DC represented by Fe, Mn, Cu-Mo, Sn, and Au and in Paleo- to Mesoproterozoic (2.2 to 1.5. Ga) in the mobile belts of SC, CITZ, ADOB and the Himalaya (Au, Cu-U, P-Fe, Mn, Zn-Pb-Cu, Pb-Zn deposits) and in intra-cratonic basins (Mn, Pb-Zn, U). In Neoproterozoic (1.0-0.75. Ga), the western fringe of ADOB saw VMS-type Zn-Pb-Cu and Zn-Cu mineralization as well as granite-related Sn-W deposits. Three of these metallogenic epochs coincide closely with Precambrian Supercontinent assembly of Kenorland (~. 2.7. Ga), Columbia (~. 1.8) and Rodinia (~. 1.0. Ga) respectively, as well as with the peaks of juvenile crustal growth in Neoarchean and Paleoproterozoic. © 2013 Elsevier B.V.

Pratap R.,University of Delhi | Ram V.J.,University of Lucknow
Chemical Reviews | Year: 2014

A study focuses on providing information about the natural products of chromene, furochromenes, pyranochromenes, and benzochromene ring systems, along with the synthesis of various aromatized and partially reduced chromenes, benzo-, and naphtho-fused chromenes, thiochromenopyrans, and their applications in synthetic organic chemistry for the construction of numerous diverse compounds. It is demonstrated that the presence of nitro group at C-5 in XVIIa,b affects the chemical shifts of H-4 and H-6 protons, and they resonate downfield as compared to respective protons of XVIIc due to the presence of electron-withdrawing substituents. It has also been observed that various substituted 2H-chromenes isolated from the leaves of Orthosiphom aristatus have been used as traditional medicine for the treatment of hypertension and diabetes.

Sharma A.,University of Delhi
Progress in Biophysics and Molecular Biology | Year: 2013

In trangenerational epigenetic inheritance, phenotypic information not encoded in DNA sequence is transmitted across generations. In germline-dependent mode, memory of environmental exposure in parental generation is transmitted through gametes, leading to appearance of phenotypes in the unexposed future generations. The memory is considered to be encoded in epigenetic factors like DNA methylation, histone modifications and regulatory RNAs. Environmental exposure may cause epigenetic modifications in the germline either directly or indirectly through primarily affecting the soma. The latter possibility is most intriguing because it contradicts the established dogma that hereditary information flows only from germline to soma, not in reverse. As such, identification of the factor(s) mediating soma to germline information transfer in transgenerational epigenetic inheritance would be pathbreaking. Regulatory RNAs and hormone have previously been implicated or proposed to play a role in soma to germline communication in epigenetic inheritance. This review examines the recent examples of gametogenic transgenerational inheritance in plants and animals in order to assess if evidence of regulatory RNAs and hormones as mediators of information transfer is supported. Overall, direct evidence for both mobile regulatory RNAs and hormones is found to exist in plants. In animals, although involvement of mobile RNAs seems imminent, direct evidence of RNA-mediated soma to germline information transfer in transgenerational epigenetic inheritance is yet to be obtained. Direct evidence is also lacking for hormones in animals. However, detailed examination of recently reported examples of transgenerational inheritance reveals circumstantial evidence supporting a role of hormones in information transmission. © 2012 Elsevier Ltd.

Kamei R.G.,University of Delhi
Proceedings. Biological sciences / The Royal Society | Year: 2012

The limbless, primarily soil-dwelling and tropical caecilian amphibians (Gymnophiona) comprise the least known order of tetrapods. On the basis of unprecedented extensive fieldwork, we report the discovery of a previously overlooked, ancient lineage and radiation of caecilians from threatened habitats in the underexplored states of northeast India. Molecular phylogenetic analyses of mitogenomic and nuclear DNA sequences, and comparative cranial anatomy indicate an unexpected sister-group relationship with the exclusively African family Herpelidae. Relaxed molecular clock analyses indicate that these lineages diverged in the Early Cretaceous, about 140 Ma. The discovery adds a major branch to the amphibian tree of life and sheds light on both the evolution and biogeography of caecilians and the biotic history of northeast India-an area generally interpreted as a gateway between biodiversity hotspots rather than a distinct biogeographic unit with its own ancient endemics. Because of its distinctive morphology, inferred age and phylogenetic relationships, we recognize the newly discovered caecilian radiation as a new family of modern amphibians.

Jain A.K.,University of Delhi
Journal of Bone and Joint Surgery - Series B | Year: 2010

The dismal outcome of tuberculosis of the spine in the pre-antibiotic era has improved significantly because of the use of potent antitubercular drugs, modern diagnostic aids and advances in surgical management. MRI allows the diagnosis of a tuberculous lesion, with a sensitivity of 100% and specificity of 88%, well before deformity develops. Neurological deficit and deformity are the worst complications of spinal tuberculosis. Patients treated conservatively show an increase in deformity of about 15°. In children, a kyphosis continues to increase with growth even after the lesion has healed. Tuberculosis of the spine is a medical disease which is not primarily treated surgically, but operation is required to prevent and treat the complications. Panvertebral lesions, therapeutically refractory disease, severe kyphosis, a developing neurological deficit, lack of improvement or deterioration are indications for surgery. Patients who present with a kyphosis of 60° or more, or one which is likely to progress, require anterior decompression, posterior shortening, posterior instrumented stabilisation and anterior and posterior bone grafting in the active stage of the disease. Late-onset paraplegia is best prevented rather than treated. The awareness and suspicion of an atypical presentation of spinal tuberculosis should be high in order to obtain a good outcome. Therapeutically refractory cases of tuberculosis of the spine are increasing in association with the presence of HIV and multidrug-resistant tuberculosis. ©2010 British Editorial Society of Bone and Joint Surgery.

Kalia V.C.,University of Delhi
Biotechnology Advances | Year: 2013

Excessive and indiscriminate use of antibiotics to treat bacterial infections has lead to the emergence of multiple drug resistant strains. Most infectious diseases are caused by bacteria which proliferate within quorum sensing (QS) mediated biofilms. Efforts to disrupt biofilms have enabled the identification of bioactive molecules produced by prokaryotes and eukaryotes. These molecules act primarily by quenching the QS system. The phenomenon is also termed as quorum quenching (QQ). In addition, synthetic compounds have also been found to be effective in QQ. This review focuses primarily on natural and synthetic quorum sensing inhibitors (QSIs) with the potential for treating bacterial infections. It has been opined that the most versatile prokaryotes to produce QSI are likely to be those, which are generally regarded as safe. Among the eukaryotes, certain legumes and traditional medicinal plants are likely to act as QSIs. Such findings are likely to lead to efficient treatments with much lower doses of drugs especially antibiotics than required at present. © 2012 Elsevier Inc.

Kumar S.,University of Delhi
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2011

A class of neutrino mass matrices with texture zeros realizable using the group Z3 within the framework of type (I+II) seesaw mechanism naturally admits a nonzero θ13, and allows for deviations from maximal mixing. The phenomenology of this model is reexamined in the light of recent hints for nonzero θ13. © 2011 American Physical Society.

Kumar G.,University of Delhi | Gupta R.,University of Delhi
Chemical Society Reviews | Year: 2013

Designed materials offer noteworthy applications which are often architecture dependent. Despite knowing such a fact, one of the major challenges faced by the scientific community is to find ways to predict and, if possible, control the resultant architecture of a network. If such an exercise is fruitful, it creates enormous opportunities to synthesize exotic materials with tailor-made applications. Any network is composed of individual molecules and the transition from a single molecule to a network can be achieved through several routes taking advantage of synthetic chemistry. There exists a molecular building block at the heart of such a transition which mediates such a process from a single molecule to a network. Although a large number of building blocks have created assorted materials, utilization of a well-defined coordination complex as the building block (i.e., metalloligand) is unique for the construction of a designed architecture. A coordination complex as the building block offers structural rigidity that places the auxiliary functional groups to a pre-organized conformation. Such auxiliary functional groups could then coordinate a secondary metal ion or be involved in the self-assembly via weak interactions, such as hydrogen bonds. This review focuses on the recent progress achieved through assorted molecular building blocks towards generating ordered networks. Broadly, two classes of metalloligands will be discussed: those offering hydrogen bond sensitive functional groups and those tendering coordination bond responsive groups. Nevertheless, the result is the construction of networks of a highly-ordered nature in both cases. The present review is expected to provide new strategies for constructing functional materials through metalloligands for challenging and practical applications. © 2013 The Royal Society of Chemistry.

Kumar A.,University of Delhi | Venkatesu P.,University of Delhi
Chemical Reviews | Year: 2012

An overview of the stability of α-Chymotrypsin (CT) in different solvent media is studied. The degree of stabilization of CT depends on the type of the solvent and the additive and is related to the form of the enzyme (soluble or immobilized) existing in the system. Organic solvents influenced the 3D structure of the CT thereby affecting the stability of the enzyme. If the enzyme exists in immobilized form, its stability depends also on the nature of the support. Protein functional groups in aqueous solution are surrounded by a hydration shell, which is composed of water molecules attached to the protein surface. Solvent hydrophobicity and polarity indirectly influence enzyme activity by affecting the hydration level of the enzyme. It is possible that the ILs reinforce CT structure such that it is able to perform its function more readily, which would account for the most effective stabilizing agents. However, ILs differ in the length of the alkyl group attached to the imidazolium cation, thus presumably differing in their hydrophobicity and ability to interact with the enzyme.

Gopalaiah K.,University of Delhi
Chemical Reviews | Year: 2013

Asymmetric metal-catalytic reactions can produce large quantities of chiral products with a very high efficiency using small amounts of chiral metal catalysts. Much of the work in asymmetric metal catalysis has been performed using noble metals based on rhodium, palladium, ruthenium, and iridium complexes. The next phase of development is the application of iron catalysis in asymmetric synthesis. There are significant developments in the design and use of chiral iron catalysts beginning with Groves discovery of catalytic asymmetric epoxidations with chiral iron-porphyrins in 1983. Cytochromes are redox enzymes, distributed widely in all living cells. They are conjugated proteins having an iron-porphyrin as prosthetic group. Cytochrome c and cytochrome P-450 are the most extensively studied oxidases. They bring about a wide range of stereoselective transformations, such as epoxidations, hydroxylations and others.

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