76
|
Kumar U, Shankar R, Wagh M, Madhubabu M, Vembu N. A Concise and Cascade Synthesis of Batracylin and Substituted Isoindolo-[1,2-b]quinazolin-12(10H)-ones. Synlett 2011. [DOI: 10.1055/s-0030-1259921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
77
|
Hasker E, Singh SP, Malaviya P, Singh RP, Shankar R, Boelaert M, Sundar S. Management of visceral leishmaniasis in rural primary health care services in Bihar, India. Trop Med Int Health 2011; 15 Suppl 2:55-62. [PMID: 20591081 DOI: 10.1111/j.1365-3156.2010.02562.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE In 2005 a visceral leishmaniasis (VL) elimination initiative was launched on the Indian subcontinent, with early diagnosis based on a rapid diagnostic test and treatment with the oral drug miltefosine as its main strategy. Several recent studies have signaled underreporting of VL cases in the region. Information on treatment outcomes is scanty. Our aim was to document VL case management by the primary health care services in India. METHODS We took a random sample of all VL patients registered in rural primary health care (PHC) facilities of Muzaffarpur district, Bihar, India during 2008. Patients were traced at home for an interview and their records were reviewed. We recorded patient and doctor delay, treatment regimens, treatment outcomes and costs incurred by patients. RESULTS We could review records of all 150 patients sampled and interview 139 patients or their guardian. Most patients (81%) had first presented to unqualified practitioners; median delay before reaching the appropriate primary healthcare facility was 40 days (IQR 31-59 days). Existing networks of village health workers were under-used. 48% of VL patients were treated with antimonials; 40% of those needed a second treatment course. Median direct expenditure by patients was 4000 rupees per episode (IQR 2695-5563 rupees), equivalent to almost 2 months of household income. CONCLUSION In 2008 still critical flaws remained in VL case management in the primary health care services in Bihar: obsolete use of antimonials with high failure rates and long patient delay. To meet the target of the VL elimination, more active case detection strategies are needed, and village health worker networks could be more involved. Costs to patients remain an obstacle to early case finding.
Collapse
|
78
|
Kumar U, Wagh M, Shankar R, Gill C. A Concise and Convergent Synthesis of Luotonin B and E. Synlett 2010. [DOI: 10.1055/s-0030-1259098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
79
|
Shankar R, Kolandaivel P, Senthilkumar L. Interaction studies of cysteine with Li+, Na+, K+, Be2+, Mg2+, and Ca2+ metal cation complexes. J PHYS ORG CHEM 2010. [DOI: 10.1002/poc.1786] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
80
|
Dhochak K, Shankar R, Tripathi V. Magnetic impurities in the honeycomb Kitaev model. PHYSICAL REVIEW LETTERS 2010; 105:117201. [PMID: 20867601 DOI: 10.1103/physrevlett.105.117201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Revised: 08/12/2010] [Indexed: 05/29/2023]
Abstract
We study the effect of coupling magnetic impurities to the honeycomb lattice spin-1/2 Kitaev model in its spin-liquid phase. We show that a spin-S impurity coupled to the Kitaev model is associated with an unusual Kondo effect with an intermediate coupling unstable fixed point Kc∼J/S separating topologically distinct sectors of the Kitaev model. We also show that the massless spinons in the spin-liquid mediate an interaction of the form Siα2Sjβ2/Rij3 between distant impurities unlike the usual dipolar RKKY interaction SiαSjα/Rij3 noted in various 2D impurity problems with a pseudogapped density of states of the spin bath. Furthermore, this long-range interaction is possible only if the impurities (a) couple to more than one neighboring spin on the host lattice and (b) the impurity spin S≠1/2.
Collapse
|
81
|
Ramesh A, Banwet D, Shankar R. Modeling the barriers of supply chain collaboration. JOURNAL OF MODELLING IN MANAGEMENT 2010. [DOI: 10.1108/17465661011061014] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
82
|
Prabhu A, Saini D, Patadiya B, Shankar R. SU-GG-T-531: A Unique Method for End-To-End Quality Assurance Test for Trigeminal Neuralgia Treatments in CyberKnife. Med Phys 2010. [DOI: 10.1118/1.3468928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
83
|
Mondal S, Sen D, Sengupta K, Shankar R. Tuning the conductance of dirac fermions on the surface of a topological insulator. PHYSICAL REVIEW LETTERS 2010; 104:046403. [PMID: 20366724 DOI: 10.1103/physrevlett.104.046403] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2009] [Indexed: 05/29/2023]
Abstract
We study the transport properties of the Dirac fermions with a Fermi velocity v{F} on the surface of a topological insulator across a ferromagnetic strip providing an exchange field J over a region of width d. We show that the conductance of such a junction, in the clean limit and at low temperature, changes from oscillatory to a monotonically decreasing function of d beyond a critical J. This leads to the possible realization of a magnetic switch using these junctions. We also study the conductance of these Dirac fermions across a potential barrier of width d and potential V0 in the presence of such a ferromagnetic strip and show that beyond a critical J, the criteria of conductance maxima changes from chi=eV{0}d/variant Planck's over v{F}=npi to chi=(n+1/2)pi for integer n. We point out that these novel phenomena have no analogs in graphene and suggest experiments which can probe them.
Collapse
|
84
|
Shankar R, Johnson MP, Williamson NA, Cullinane F, Purcell AW, Moses EK, Brennecke SP. Molecular markers of preterm labor in the choriodecidua. Reprod Sci 2009; 17:297-310. [PMID: 20009011 DOI: 10.1177/1933719109353454] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Because relevant biochemical changes are known to begin at the choriodecidual interface some weeks before actual clinical onset of labor, we hypothesized that the preterm choriodecidua may display gene and protein expression patterns specific to preterm labor. Transcriptomic (microarray) and proteomic (2-dimensional gel electrophoresis [2DGE]) profiling methodologies were used to compare changes in choriodecidual tissue collected from women who delivered before 35 weeks of gestation following spontaneous preterm labor (n = 12) and gestation-matched nonlaboring controls (n = 7). Additionally, 2DGE was used to compare differences in protein expression during term and preterm labor and to construct a choriodecidual proteome map. Overall, expressed transcripts and proteins indicated active tissue remodeling independent of labor status and an association with inflammatory processes during labor. Spontaneous, infection-induced and abruption-associated preterm deliveries were each defined by distinct transcriptional profiles. Proteins osteoglycin and progesterone receptor component 2 (PGRMC2) were upregulated during term and preterm labor while galectin 1, annexin 3, annexin 5, and protein disulfide isomerase (PDI) were upregulated only during preterm labor, suggesting a probable association with the underlying pathology. Together, these results represent novel data that warrant further investigations to elucidate plausible causal relationships of these molecules with spontaneous preterm delivery.
Collapse
|
85
|
Candiotti K, Sharma S, Shankar R. Obesity, obstructive sleep apnoea, and diabetes mellitus: anaesthetic implications. Br J Anaesth 2009; 103 Suppl 1:i23-30. [DOI: 10.1093/bja/aep294] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
|
86
|
Senthil T, Shankar R. Fermi surfaces in general codimension and a new controlled nontrivial fixed point. PHYSICAL REVIEW LETTERS 2009; 102:046406. [PMID: 19257450 DOI: 10.1103/physrevlett.102.046406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2008] [Indexed: 05/27/2023]
Abstract
The energy of a d-dimensional Fermi system typically varies only along d(c)=1 ("radial") dimensions. We consider d(c)=1+epsilon and study a transition to superconductivity in an epsilon expansion. The nontrivial fixed point describes a scale invariant theory with an effective space-time dimension D=d(c)+1. Remarkably, the results can be reproduced by the Hertz-Millis action for the superconducting order parameter in higher effective space-time dimensions. We consider possible realizations of the transition at epsilon=1, which corresponds to a linear Fermi surface in d=3.
Collapse
|
87
|
Syam Kumar U, Shanmugapriya D, Shankar R, Satyanarayana G, Dahanukar V, Vembu N. Aerial Oxidation of 2,2-Dibromo-1-Aryl and Heteroaryl Ethanones: A Facile Synthesis of Aryl and Heteroaryl α-Keto Amides. Synlett 2008. [DOI: 10.1055/s-0028-1087353] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
88
|
Dutta SB, Shankar R. Bosonization, coherent states and semiclassical quantum Hall skyrmions. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2008; 20:275237. [PMID: 21694398 DOI: 10.1088/0953-8984/20/27/275237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We bosonize (2+1)-dimensional fermionic theory using coherent states. The gauge-invariant subspace of boson-Chern-Simons Hilbert space is mapped to fermionic Hilbert space. This subspace is then equipped with a coherent state basis. These coherent states are labelled by a dynamic spinor field. The label manifold could be assigned a physical meaning in terms of density and spin density. A path-integral representation of the evolution operator in terms of these physical variables is given. The corresponding classical theory when restricted to LLL is described by spin fluctuations alone and is found to be the NLSM with Hopf term. The formalism developed here is suitable to study quantum Hall skyrmions semiclassically and/or beyond the hydrodynamic limit. The effects of Landau level mixing or the presence of slowly varying external fields can also be easily incorporated.
Collapse
|
89
|
Abstract
BACKGROUND Appendectomy is one of the commonest procedures in surgery. In spite of various investigations used to improve the accuracy of diagnosis, the rate of normal appendices removed is still about 15-30%. Many studies have investigated the role of C-reactive protein (CRP) in acute appendicitis, but with conflicting results. METHODS In a prospective, double blind study, blood for the measurement of serum C-reactive protein was collected pre-operatively from 192 children before going to the operating theatre for appendectomy. The histopathology was grouped into positive (acute appendicitis) and negative (normal appendix) and this was correlated with CRP values. RESULTS CRP was normal in 14 out of 33 negative explorations (normal appendix on histopathology). The specificity and sensitivity of serum CRP was 42% and 91% respectively. The predictive value of a positive (raised CRP) and negative (normal CRP) test is 88% and 48% respectively. CONCLUSION We conclude that neither raised nor normal CRP value is helpful in the diagnosis of acute appendicitis. CRP is not a good tool for helping the surgeon make the diagnosis of appendicitis and it should not be measured in suspected appendicitis.
Collapse
|
90
|
Ramesh A, Banwet D, Shankar R. Modelling the enablers of supply chain collaboration. ACTA ACUST UNITED AC 2008. [DOI: 10.1504/ijlsm.2008.019182] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
91
|
Subrammaniyan S, Rajkumar M, Amalopavanathan J, Shankar R, Manjunath S, Senthil Kumar R, Abraham S. Our Experience in treating Ischemic Ulcer of a Lower Limb in 4 diabetic patients with Autologous Bone Marrow Stem Cells. J Stem Cells Regen Med 2007; 3:30-31. [PMID: 24693022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
|
92
|
Jain R, Singh G, Shankar R. A comparative evaluation of bone regeneration in osseous defects using hydroxyapatite graft and the extent of ossification in osseous defects treated without grafts. Int J Oral Maxillofac Surg 2007. [DOI: 10.1016/j.ijom.2007.08.175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
93
|
Baskaran G, Mandal S, Shankar R. Exact results for spin dynamics and fractionalization in the Kitaev Model. PHYSICAL REVIEW LETTERS 2007; 98:247201. [PMID: 17677986 DOI: 10.1103/physrevlett.98.247201] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2007] [Indexed: 05/16/2023]
Abstract
We present certain exact analytical results for dynamical spin correlation functions in the Kitaev Model. It is the first result of its kind in nontrivial quantum spin models. The result is also novel: in spite of the presence of gapless propagating Majorana fermion excitations, dynamical two spin correlation functions are identically zero beyond nearest neighbor separation. This shows existence of a gapless but short range spin liquid. An unusual, all energy scale fractionalization of a spin-flip quanta, into two infinitely massive pi fluxes and a dynamical Majorana fermion, is shown to occur. As the Kitaev Model exemplifies topological quantum computation, our result presents new insights into qubit dynamics and generation of topological excitations.
Collapse
|
94
|
Shankar R, Kolandaivel P, Nirmala V, Narayandass SK. Molecular Interaction of H 2, N 2, and HF Molecules with the Silicon Carbide (SiC) n=5−9 Clusters: A Theoretical Study. ACTA ACUST UNITED AC 2007. [DOI: 10.1166/jctn.2007.2368] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
95
|
Lukose V, Shankar R, Baskaran G. Novel electric field effects on Landau levels in graphene. PHYSICAL REVIEW LETTERS 2007; 98:116802. [PMID: 17501075 DOI: 10.1103/physrevlett.98.116802] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2006] [Indexed: 05/15/2023]
Abstract
A new effect in graphene in the presence of crossed uniform electric and magnetic fields is predicted. Landau levels are shown to be modified in an unexpected fashion by the electric field, leading to a collapse of the spectrum, when the value of electric to magnetic field ratio exceeds a certain critical value. Our theoretical results, strikingly different from the standard 2D electron gas, are explained using a "Lorentz boost," and as an "instability of a relativistic quantum field vacuum." It is a remarkable case of emergent relativistic type phenomena in nonrelativistic graphene. We also discuss few possible experimental consequence.
Collapse
|
96
|
Shankar S, Shankar R, Considine R, Steinberg H. Effects of Insulin and Free Fatty Acids on Asymmetric Dimethyl Arginine, a Novel Cardiovascular Risk Factor. J Investig Med 2007. [DOI: 10.1177/108155890705500260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
|
97
|
Shankar SS, Shankar R, Considine RV, Steinberg HO. 60 EFFECTS OF INSULIN AND FREE FATTY ACIDS ON ASYMMETRIC DIMETHYL ARGININE, A NOVEL CARDIOVASCULAR RISK FACTOR. J Investig Med 2007. [DOI: 10.1136/jim-55-02-60] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
98
|
Melstrom K, Kozlowski R, Hassett D, Shankar R, Gamelli R. 200. J Surg Res 2007. [DOI: 10.1016/j.jss.2006.12.215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
99
|
Shankar R, Tondon J, Gambhir IS, Tripathi CB. Health status of elderly population in rural area of Varanasi district. Indian J Public Health 2007; 51:56-58. [PMID: 18232146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023] Open
Abstract
In order to assess the health problems of the elderly people and its relationship with advancement of age, a field based cross sectional study was carried out in two selected villages in the rural field practices area in Varanasi district. 88.8 % were found to suffer from one or more illness at the time of study. This resulted in the morbidity load of 1.93 illnesses per person. The morbidity was directly proportional to the age. The most common morbidity was arthritis with overall prevalence of 57.08% followed by cataract (48.33%), hypertension (11.25%). But the prevalence of old age related morbidities increased with advancing age (p<0.008). Compared to married people higher percentage of widow / widower (91.5%) suffered from old age related morbidities (p<0.01).
Collapse
|
100
|
|