74 results on '"SURESH, KG"'
Search Results
2. Comparing Financial Debt Choices of Existing and New SMEs in Indian Manufacturing Sector
- Author
-
Suresh, KG, primary, Saxena, Akanksha, additional, and Srikanth, M., additional
- Published
- 2022
- Full Text
- View/download PDF
3. AN EMPIRICAL INVESTIGATION ABOUT RELATIONSHIP BETWEEN INTERNATIONAL TRADE AND TOURIST ARRIVAL: EVIDENCE FROM INDIA
- Author
-
Vikas GAUTAM and Suresh KG
- Subjects
international trade ,international tourism ,india ,unit root test ,granger causality test ,Management. Industrial management ,HD28-70 ,Business ,HF5001-6182 - Abstract
This study aims to examine the causal relationship between tourism arrivals and bilateral trade of India with Germany, Netherland, Switzerland, France, Italy, USA, UK and Canada for the period 1996 January to 2008 December. After examining the order of integration by using the Zivot and Andrews structural unit root test, we have used the Granger Causality test to examine the causal relationship between the study variables. The Granger Causality test results indicate two way causal relationships between the Trade and Tourism in case of USA, Italy and Canada.
- Published
- 2012
4. Characterization of d and f Electronic States in RSn1.1Ge0.9 (R=Gd, Tb) Compounds by Optical Spectroscopy and Electronic-Structure Calculations
- Author
-
KNYAZEV, YV, LUKOYANOV, AV, KUZ'MIN, YI, GUPTA, S, and SURESH, KG
- Subjects
optical properties ,rare-earth alloys and compounds ,ER ,GD ,electronic band structure ,TM ,optical spectroscopy ,MAGNETISM - Abstract
This paper presents the results of investigations of the electronic structure and optical properties of the GdSn1.1Ge0.9 and TbSn1.1Ge0.9 compounds. Employing the local spin density approximation accounting for strong electronic correlations in the 4f-shell of rare-earth ions, that is the LSDA+U method, we carry out the spin-polarized calculations of band structure. In a broad range of wavelengths the optical constants of the compounds are measured by an ellipsometry method. A number of spectral and electronic characteristics are calculated. Based on the calculated density of states the structural features of optical conductivity for the investigated intermetallic compounds are interpreted in the region of interband absorption.
- Published
- 2018
5. Quantum phase transition and non-Fermi liquid behavior in Fe1-xCoxSi (x >= 0.7)
- Author
-
SAMATHAM, SS, SURESH, KG, and GANESAN, V
- Subjects
Fe1-xCoxSi ,ALLOYS ,thermoelectric power ,magnetization ,STATE ,correlated electron systems ,resistivity ,FERROMAGNETS ,MAGNETIC-PROPERTIES ,FEXCO1-XSI ,specific heat ,ELECTRON ,METALS ,non-Fermi liquid - Abstract
We report on the nature of electron correlations in Fe1-xCoxSi (0.7
- Published
- 2018
6. Improved Coercivity of Solvothermally Grown Hematite (alpha-Fe2O3) and Hematite/Graphene Oxide Nanocomposites (alpha-Fe2O3/GO) at Low Temperature
- Author
-
SATHEESH, M, PALOLY, AR, SAGAR, CKK, SURESH, KG, and BUSHIRI, MJ
- Subjects
rkky interaction ,alpha -Fe(2)O(3/)GO ,MORIN TRANSITION ,morin transition temperature ,NANOCRYSTALS ,SIZE ,MAGNETIC-PROPERTIES ,AMORPHOUS-CARBON ,solvothermal ,COMPOSITES ,coercivity ,REDUCED GRAPHENE OXIDE ,LITHIUM-ION BATTERIES ,MATRICES - Abstract
alpha-Fe2O3 and alpha-Fe2O3/graphene oxide (GO) nanocomposites are synthesized by solvothermal method in acetonitrile medium at 200 degrees C. XRD studies reveals the formation of alpha-Fe2O3 and alpha-Fe2O3/GO nanocomposites. Raman studies indicate that GO in alpha-Fe2O3/GO system was more disordered than GO. The enhanced low temperature magnetic saturation and coercivity in alpha-Fe2O3 and alpha-Fe2O3/GO are related to frozen canted spins. Blocking temperature of alpha-Fe2O3/GO is 348 K, which also shows higher coercivity of the order of about 3064 Oe at 5 K. The alpha-Fe2O3/GO composite exhibits thermal hysteresis at Morin transition (Delta T-M = 11K).
- Published
- 2018
7. Electronic and Spectral Properties of RRhSn (R = Gd, Tb) Intermetallic Compounds
- Author
-
KNYAZEV, YV, LUKOYANOV, AV, KUZ'MIN, YI, GUPTA, S, and SURESH, KG
- Subjects
MAGNETIC-PROPERTIES ,GDRHSN - Abstract
The investigations of electronic structure and optical properties of GdRhSn and TbRhSn were carried out. The calculations of band spectrum, taking into account the spin polarization, were performed in a local electron density approximation with a correction for strong correlation effects in 4f shell of rare earth metal (LSDA + U method). The optical studies were done by ellipsometry in a wide range of wavelengths, and the set of spectral and electronic characteristics was determined. It was shown that optical absorption in a region of interband transitions has a satisfactory explanation within a scope of calculations of density of electronic states carried out.
- Published
- 2018
8. Critical exponents and universal magnetic behavior of noncentrosymmetric Fe0.6Co0.4Si
- Author
-
SAMATHAM, SS and SURESH, KG
- Subjects
critical phenomenon ,CRYSTAL ,ALLOYS ,Dzyaloshinskii-Moriya interactions ,chiral magnetism ,exchange interaction ,ITINERANT-ELECTRON FERROMAGNETS ,SEMICONDUCTOR ,TRANSITIONS ,EQUATION-OF-STATE ,SPIN-DENSITY-WAVE ,FEXCO1-XSI ,METAL ,TEMPERATURE - Abstract
The critical magnetic properties of a non-centrosymmetric B20 cubic helimagnet Fe0.6Co0.4Si are investigated using magnetization isotherms. It belongs to the 3D-Heisenberg universality class with short range magnetic coupling as inferred from the self-consistent critical exponents beta = 0.411 +/- 0.003, gamma = 1.325 +/- 0.062, delta = 4.223 +/- 0.004 and alpha = -0.115 +/- 0.007 in combination with exchange interaction J(r) approximate to r-(4.88). Itinerant magnetic nature of the compound is realized by the Rhodes-Wholfarth analysis. Field-induced weak first (para?helical) to second (para?field-polarized) order transition is reported to occur at low critical field due to the weak spin-orbit coupling arising from the weak Dzyaloshinksii-Moriya interactions. Our study suggests the distinct phenomenological magnetic structures for Fe-based cubic magnets (Fe1-xCoxSi and FeGe) and MnSi which cause contrasting physical properties.
- Published
- 2018
9. Competing magnetic and spin-gapless semiconducting behavior in fully compensated ferrimagnetic CrVTiAl: Theory and experiment
- Author
-
VENKATESWARA, Y, GUPTA, S, SAMATHAM, SS, VARMA, MR, ENAMULLAH, SURESH, KG, and ALAM, A
- Subjects
SPINTRONICS ,HEUSLER ALLOYS - Abstract
We report the structural, magnetic, and transport properties of the polycrystalline CrVTiAl alloy along with first-principles calculations. The alloy crystallizes in a LiMgPdSn-type structure with a lattice parameter of 6.14 angstrom at room temperature. The absence of the (111) peak along with the presence of a weak (200) peak indicates the antisite disorder of Al with Cr and V atoms, which is different from the pure DO3 type. Magnetization measurements reveal amagnetic transition near 710 K, a coercive field of similar to 100 Oe at 3 K, and a moment of similar to 10(-3) mu(B)/f.u. These observations are indicative of fully compensated ferrimagnetism in the alloy, which is confirmed by theoretical modeling. The temperature coefficient of resistivity is found to be negative, signaling the semiconducting nature. However, the absence of exponential dependence indicates the semiconducting nature with gapless/spin-gapless behavior. Electronic and magnetic properties of CrVTiAl for all three possible crystallographic configurations are studied theoretically. All the configurations are found to be different forms of semiconductors. The ground-state configuration is a fully compensated ferrimagnet with band gaps of 0.58 and 0.30 eV for the spin-up and -down bands, respectively. The next-higher-energy configuration is also fully compensated ferrimagnetic but has a spin-gapless semiconducting nature. The highest-energy configuration corresponds to a nonmagnetic, gapless semiconductor. The energy differences among these configurations are quite small (< 1 mRy/atom), which hints that, at finite temperatures, the alloy exists in a disordered phase, which is a mixture of the three configurations. By taking into account the theoretical and experimental findings, we conclude that CrVTiAl is a fully compensated ferrimagnet with a predominantly spin-gapless semiconducting nature.
- Published
- 2018
10. Magnetic properties and large reversible magnetocaloric effect in Er3Pd2
- Author
-
MAJI, B, RAY, MK, MODAK, M, MONDAL, S, SURESH, KG, and BANERJEE, S
- Subjects
ER ,Rare earth ,Intermetallic ,Reversible magnetocaloric effect ,RE ,INTERMETALLIC COMPOUNDS ,DY ,HO COMPOUNDS ,TRANSITION ,ENTROPY CHANGE - Abstract
The magnetic properties and magnetocaloric effect (MCE) of binary intermetallic compound Er3Pd2 were studied. It exhibits a paramagnetic (PM) to antiferromagnetic (AFM) transition at Neel temperature (T-N) = 10 K. A large reversible MCE was observed which is related to a second order magnetic transition from PM to AFM state. The values of maximum magnetic entropy change (-Delta S-M(max)) and adiabatic temperature change (Delta T-ad(max)) reach 8.9 J/kg-K and 2.9 K respectively for the field change of 50 kOe with no obvious hysteresis loss. The effective magnetic moment was determined to be 10.16 mu(B)/Er3+, which is notably higher than that of free ion value of Er3+ (9.59 mu(B)), suggests that Pd ions also have considerable amount of magnetic moments in this compound. (C) 2018 Elsevier B.V. All rights reserved.
- Published
- 2018
11. Magnetization, resistivity, specific heat and ab initio calculations of Gd5Sb3
- Author
-
SAMATHAM, SS, PATEL, AK, LUKOYANOV, AV, and SURESH, KG
- Subjects
ELECTRONIC-STRUCTURE ,SYSTEMS ,antiferromagnetism ,CRYSTAL-STRUCTURE ,magnetic phase transitions ,Gd5Sb3 ,TRANSITION - Abstract
We report on the combined results of the structural, magnetic, transport and calorimetric properties of Mn5Si3-type hexagonal Gd5Sb3, together with ab initio calculations. It exhibits a ferromagnetic (FM)-like transition at 265 K, antiferromagnetic (AFM) Noel transition at 95.5 K followed by a spin-orientation transition at 62 K. The system is found to be in AFM state down to 2 K in a field of 70 kOe. The FM-AFM phase coexistence is not noticeable despite large positive Curie-Weiss temperature (theta(CW) = 223.5 +/- 0.2 K). Instead, low-temperature AFM and high-temperature FM-like phases are separated in large temperatures. Temperature-magnetic field (H-T) phase diagram reveals field-driven complex magnetic phases. Within the AFM phase, the system is observed to undergo field-driven spin-orientation transitions. Field-induced tricritical and quantum critical points appear to be absent due to the strong AFM nature and by the intervention of FM-like state between paramagnetic and AFM states, respectively. The metallic behavior of the compound is inferred from resistivity along with large Sommerfeld parameter. However, no sign of strong electron-correlations is reasoned from the Kadowaki-Wood's ratio A/gamma(2) similar to 1.9 x 10(-6) mu Omega . cm . (mol . K)(2) (mJ)(-2), despite heavy gamma. Essentially, ab initio calculations accounting for electronic correlations confirm AFM nature of low-temperature magnetic state in Gd5Sb3 and attainable FM ordering in agreement with experimental data.
- Published
- 2018
12. Post-operative management of pediatric heart transplantation : A brief review
- Author
-
Balakrishnan, KR, primary, Suresh, KG, additional, Muralikrishna, T, additional, and Kumar, RSuresh, additional
- Published
- 2018
- Full Text
- View/download PDF
13. Structural, transport and magnetic properties of Sr(2)RuTiO(6)
- Author
-
PILLAI, SS, SANTHOSH, PN, THOMAS, PJ, TUNA, F, and SURESH, KG
- Subjects
Crystal-Structure ,Ca ,Magnetoresistance ,Transport Properties ,Resistivity ,Double Perovskite Materials ,Structural Properties ,Double Perovskites - Abstract
The double perovskite. Sr(2)RuTiO(6) has been studied by X-ray powder diffraction, magnetizations and magnetoresistance techniques. Rietveld analysis of the X-ray diffraction shows that the sample crystallizes in tetragonal structure with space group 14/mcm and there is no indication of long range Ru/Ti cation ordering. The magnetic studies point towards the existence of magnetic polarons in the paramagnetic state with a weak ferromagnetic transition at 145 K The temperature dependent magnetoresistance studies reveal an unusual cross over from positive to negative magnetoresistance at low temperature (similar to 15 K). The complex magnetotransport properties of Sr(2)RuTiO(6) arise from the competing ferromagnetic and antiferromagnetic superexchange interactions between Ru ions via Ti/O ions, initiated by the B-site cation disorder.
- Published
- 2010
- Full Text
- View/download PDF
14. Temperature and magnetic field induced structural transformation in Si-doped CeFe(2): An in-field X-ray diffraction study
- Author
-
HALDAR, A, SINGH, NK, MUDRYK, Y, SURESH, KG, NIGAM, AK, and PECHARSKY, VK
- Subjects
Intermetallics ,Phase Coexistence ,Magnetostructural Coupling ,Supercooling - Abstract
Using the X-ray powder diffraction technique at various temperatures and applied magnetic fields, we have studied the magnetostructural properties of Ce(Fe(0.9)Si(0.05))(2). The X-ray diffraction data establish quantitative relationships between bulk magnetization and the evolution of structurally distinct phases with magnetic field and temperature, and confirm the distinct features of a first-order phase transition such as supercooling and superheating. metastability, and phase co-existence of different structural polymorphs We observe the lattice volume mismatch across the structural phase transition, which appears to be the cause for the step behavior of the magnetization isotherms at low temperatures. The present study shows that the lattice distortion has to be treated explicitly, like spin, along with the effects of lattice-spin coupling to account for the magnetization behavior of this system. This structure template can resolve the issue of kinetics in this material as observed in different time scale measurements and with different experimental protocols (C) 2010 Elsevier Ltd .
- Published
- 2010
15. Vertical fragment in adult midshaft clavicle fractures: an indicator for surgical intervention
- Author
-
Sayyied J Kirmani, Suresh Kg Pillai, Babu R Madegowda, and Shantanu A Shahane
- Subjects
Adult ,Male ,medicine.medical_specialty ,Time Factors ,Adolescent ,Radiography ,Nonunion ,Joint Dislocations ,Cohort Studies ,Fractures, Bone ,Young Adult ,Postoperative Complications ,medicine ,Humans ,Orthopedics and Sports Medicine ,Young adult ,Fractures, Malunited ,Aged ,Retrospective Studies ,Aged, 80 and over ,Fracture Healing ,business.industry ,Retrospective cohort study ,Middle Aged ,medicine.disease ,Clavicle ,Surgery ,medicine.anatomical_structure ,Treatment Outcome ,Radiological weapon ,Fractures, Ununited ,Cohort ,Female ,business ,Cohort study - Abstract
This article describes a retrospective cohort study that investigated whether adult midshaft clavicle fractures possessing the radiological sign of a butterfly vertical fragment demonstrate a higher rate of early and delayed surgical intervention when compared to adult midshaft clavicle fractures with no vertical fragment sign. The radiographs of 134 adult midshaft clavicle fractures were divided into 2 cohorts: those with a vertical fragment radiological sign and those without. Within each cohort, the number of cases that underwent early surgical intervention and that underwent delayed surgical intervention was noted. The vertical fragment group displayed a rate for early surgical intervention, all for skin tenting, of 8.5%, whereas the no vertical fragment group's rate was 1.1%; this proved to be significantly different (P=.0464). Furthermore, the vertical fragment group displayed a rate for delayed surgical intervention for symptomatic nonunion of 12.8%, whereas the no vertical fragment group's rate was 5.7%. Despite being twice as likely for the vertical fragment group to have undergone delayed surgical intervention, this did not prove to be statistically significant (P=.0965). This study revealed that midshaft fractures with the radiological sign of an interfragmentary vertical fragment are significantly more likely to require early surgical intervention due to skin tenting. Furthermore, these fractures are twice as likely to go into symptomatic nonunion, and in this area we may be able to improve current management by considering early surgical intervention.
- Published
- 2009
16. Pressure-induced changes in the magnetic and magnetocaloric properties of RMn(2)Ge(2) (R=Sm,Gd)
- Author
-
KUMAR, P, SURESH, KG, NIGAM, AK, MAGNUS, A, COELHO, AA, and GAMA, S
- Subjects
Smmn2ge2 ,Transition ,Entropy Change - Abstract
We have studied the variation of magnetic and magnetocaloric properties of polycrystalline compounds SmMn(2)Ge(2) and GdMn(2)Ge(2) as a function of applied hydrostatic pressure. The magnetic transition temperatures are found to change considerably with pressure. The temperature regime of existence of antiferromagnetic (AFM) ordering is found to increase with pressure, in both the compounds. In SmMn(2)Ge(2), the sign of the magnetocaloric effect at the low-temperature ferromagnetic (FM)-AFM transition changes with pressure. The isothermal magnetic entropy change in this compound is found to increase by about 20 times as the pressure is increased from the ambient value to 6.8 kbar. Effect of pressure in GdMn(2)Ge(2) is less compared to that in SmMn(2)Ge(2). The variations in the magnetic and magnetocaloric properties are attributed to the changes in the magnetic state of the Mn sublattice under pressure. The difference in R-Mn coupling in Sm and Gd compounds is also found to play a role in determining the magnetic and magnetocaloric properties, both at ambient as well as under applied pressures.
- Published
- 2008
17. Phase relationship, microstructure and magnetocaloric effect in Gd1-x(Si0.5Ge0.5)(x) alloys
- Author
-
RAJA, MM, GOPALAN, R, RAJKUMAR, DM, BALAMURALIKRISHNAN, R, CHANDRASEKARAN, V, SURESH, KG, and HONO, K
- Subjects
System ,Silicon ,Magnetic Refrigeration ,Gd-5(Si2ge2) ,Gd5si4-Gd5ge4 ,Transition ,Gd-5(Sixge1-X)(4) - Abstract
Microstructure and magnetocaloric effect were investigated in Gd1-x(Si0.5Ge0.5)(x) alloys with x = 0.38, 0.41, 0.45, 0.47 and 0.50. The phase identification and compositional analysis were carried out by a combination of x-ray powder diffraction, scanning electron microscopy and electron probe microanalysis. The Gd-5(Si,Ge)(4) phase was found to have an orthorhombic Gd5Si4-type structure when the coexisting phase was Gd-rich (Gd5Si3-type) and a monoclinic Gd5Si2Ge2-type structure when the coexisting phase was Gd-depleted (Gd5Ge5-type). The magnetocaloric effect was found to depend on the volume fraction and the Si/Ge ratio of the ferromagnetic 5 : 4 phase in the above series of alloys. A maximum magnetocaloric effect ( Delta S) M of 14.3 J kg(-1) K-1 for a magnetic field change from 0 to 5 T was obtained for the x = 0.45 alloy.
- Published
- 2008
18. Magnetocaloric and magnetotransport properties of R(2)Ni(2)Sn compounds (R = Ce, Nd, Sm, Gd, and Tb)
- Author
-
KUMAR, P, SINGH, NK, SURESH, KG, and NIGAM, AK
- Subjects
Nd2ni2sn ,Ternary Stannide ,Electrical-Resistivity ,Magnetoresistance ,Gd-5(Si2ge2) ,Magnetic Phase-Diagram ,Transition ,Crystal ,Kondo Stannide Ce2ni2sn ,Heat-Capacity - Abstract
We report a detailed magnetic, magnetocaloric, and magnetotransport study on R(2)Ni(2)Sn compounds with different rare earths. The magnetic state of these compounds is found to be complex because of the coexistence of ferromagnetic and antiferromagnetic components. These compounds show phenomena such as multiple magnetic transitions, nonsaturation of magnetization, and metamagnetic transitions. Analysis of the zero-field heat capacity data shows that the magnetic entropy is less than the theoretical value, indicating the presence of some moment on Ni. Schottky anomaly is present in the magnetic heat capacity data of Sm(2)Ni(2)Sn. The temperature variation of magnetocaloric effect reflects the magnetization behavior. Tb(2)Ni(2)Sn and to a less extent Gd(2)Ni(2)Sn show oscillatory magnetocaloric effect. The variation of magnetocaloric effect is correlated with the ferromagnetic-antiferromagnetic phase coexistence. The electrical resistivity analysis has shown that the electron-magnon scattering is prominent at low temperature, while phonon scattering modified by the s-d interaction is crucial at high temperatures. The magnetoresistance is very large in Ce(2)Ni(2)Sn and shows a quadratic dependence on the field, implying the role of spin fluctuations in determining the transport behavior. Large magnetoresistance has been observed in other compounds as well.
- Published
- 2008
19. Anomalous magnetocaloric effect and magnetoresistance in Ho(Ni,Fe)(2) compounds
- Author
-
SINGH, NK, AGARWAL, S, SURESH, KG, NIRMALA, R, NIGAM, AK, and MALIK, SK
- Subjects
Transition ,Temperature ,Alloys ,Heat-Capacity ,Magnetic-Properties ,Honi2 - Abstract
Magnetic, magnetocaloric, and magnetoresistance studies have been carried out on polycrystalline samples of Laves phase compounds Ho(Ni1-xFex)(2) [x=0, 0.05, and 0.1]. The magnetocaloric effect in HoNi2 is found to be maximum near the ordering temperature with values of 7 J mol(-1) K-1 and 10.1 K for the isothermal magnetic entropy change and the adiabatic temperature change, respectively, for a field of 50 kOe. With Fe substitution, the temperature variation of magnetocaloric effect shows an additional peak at low temperatures, which is much more pronounced than the peak at the ordering temperature. The origin of the low temperature peak is attributed to the field-induced metamagnetic transition. The magnetoresistance data also seem to support the occurrence of the metamagnetic transition.
- Published
- 2005
20. Variations in the level of enzyme activity and immunolocalization of calcium-dependent protein kinases in the phloem of different cucumber organs
- Author
-
Kumar, Suresh KG and Jayabaskaran, Chelliah
- Subjects
Biochemistry - Abstract
Calcium-dependent protein kinases (CDPKs) constitute a unique family of enzymes in plants that are characterized by a C-terminal calmodulin (CaM)-like domain. Through protein kinase assays, we have examined the levels of cucumber calcium-dependent kinase $(C_SCDPK)$ activity in various organs of cucumber seedlings and plants. The activity of $C_SCDPK$ was highest in cucumber plant leaves followed by seedling roots and hypocotyls; however, cucumber plant flowers, seedling cotyledons, and hooks had levels that were barely detectable. The $C_SCDPKs$ were immunolocalized using polyclonal antibodies that are highly specific against a part of the kinase domain of a calcium-dependent protein kinase $(C_SCDPKS)$ in the phloem sieve elements (SEs) in various organs of cucumber. In addition, this study indicates the presence of CsCDPKs in organelle-like bodies associated with the plasma membrane of sieve elements in mature stems and roots as well as in the storage bodies of immature seeds. These findings are discussed in terms of the likely roles played by CDPKs in the signal transduction pathways for $Ca^{2+}$-regulated phloem transport of assimilates from leaves to various organs during growth and development of cucumber seedlings and plants.
- Published
- 2004
21. Scimitar Syndrome: Experience with 6 Patients
- Author
-
Karthekeyan, Ranjith Baskar, primary, Saldanha, Richard, additional, Sahadevan, M Ranjith, additional, Rao, Suresh KG, additional, Vakamudi, Mahesh, additional, and Rajagopal, Balakrishnan K, additional
- Published
- 2009
- Full Text
- View/download PDF
22. Scimitar Syndrome: Experience With 6 Patients.
- Author
-
Ranjith Baskar Karthekeyan, Saldanha, Richard, Ranjith Sahadevan, M., Rao, Suresh KG, Vakamudi, Mahesh, and Rajagopal, Balakrishnan K
- Abstract
Scimitar syndrome is a rare congenital anomaly characterized by anomalous pulmonary venous drainage to the inferior vena cava, causing a left-to-right shunt. Six patients with scimitar syndrome were diagnosed in our hospital between 2002 and 2008. There were 4 girls and 2 boys; 4 < 5 kg in weight, 2 < 8 kg in weight. Scimitar syndrome was suspected in 5 cases because of dextroversion, and diagnosed by color Doppler echocardiography in all 6 when a scimitar vein was detected entering the inferior vena cava. Computed tomography confirmed the diagnosis in all patients. Two patients had horseshoe lung, 2 had a unilobar right lung, 1 had a hypoplastic right lung, and 1 had a hypoplastic right lower lobe. Three patients had severe pulmonary arterial hypertension, 2 had moderate pulmonary arterial hypertension, and one had normal pulmonary arterial pressure. All patients had lower respiratory tract infections, volume loss of the right lung, a normal or hyperinflated left lung, dextroversion of the heart, and scimitar arteries from the descending aorta. Pneumonectomy was performed in 3 patients, lobectomy in 1, ligation of anomalous vessels in 1, and 1 died before surgery. [ABSTRACT FROM PUBLISHER]
- Published
- 2009
- Full Text
- View/download PDF
23. Spin-disorder intervened avoidance of quantum criticality in B20 cubic Mn1-xVxSi.
- Author
-
Khandelwal P, Shanmukharao Samatham S, Babu PD, and Suresh KG
- Abstract
The effect of negative chemical pressure with the substitution of transition metal V in an itinerant helimagnetically ordered MnSi, Mn1-xV
x Si with x = 0-0.1, is explored using dc and ac-susceptibilities. With increasing x , the manifestations are unaffected crystal structure with increasing unit cell volume, suppression of long-range magnetic order, weakening of itinerant character and reduced spin-cooperative phenomenon. The emergence of spin-glass behaviour forx⩾0.1intervenes in the occurrence of quantum phase transition. The constructed concentration-temperature x-T phase diagram illustrates the substitution-driven changes in the magnetism of MnSi. Further, the study suggests that the presence of a precursor state can favour the formation of spin-textures in magnetically ordered compositions0- Published
- 2024
- Full Text
- View/download PDF
24. Revealing magnetic and physical properties of TbFe 4.4 Al 7.6 : experiment and theory.
- Author
-
Samatham SS, Singh S, Shravan Kumar Reddy S, A SK, Yadam S, Babu PD, Takeuchi T, and Suresh KG
- Abstract
We report on the magnetic, electrical transport, caloric and electronic structure properties of TbFe
4.4 Al7.6 polycrystalline alloy using experiment and theory. The alloy crystallizes in tetragonal structure with I4/mmm space group with lattice parameters a = b = 8.7234(5) Å and c = 5.0387(6) Å. It is ferrimagnetic with a compensation temperature ofTcmp∼151 K, Curie-Weiss temperatureθCW∼172.11 K and an effective magnetic momentμeff= (2.37±0.07)μB/f.u with Z = 2. At low temperatures, kinetic arrest-like first-order phase transition is realized through the thermal hysteresis between field-cooled cooling and field-cooled warming curves of M ( T ) and virgin curves of M ( H ) andρ(H)which are outside the hysteresis loops with metamagnetic transition. The high magnetic field suppression of multiple transitions and reduced coercive fieldHcoerand remnant magnetizationMremwith increasing temperature are reported.HcoerandMremcease to exist above the compensation temperatureTcmp. A correlation between the isothermal magnetization and resistivity is discussed. Specific heat C ( T ) analysis reveals a Sommerfeld parameter of γ = 0.098 J⋅mol-1⋅K-2and a Debye temperature ofθD∼351.2 K. The sample is metallic as inferred from theρ(T)behavior and Sommerfeld parameter. The magnetoresistance of the alloy is low and negative which indicates the suppression of weak spin-fluctuations. This alloy avoids the tricritical point despite first-to-second order phase transition. The electronic and magnetic structure calculations, by making use of full potential linearized augmented plane wave method, suggest metallic ferrimagnetic ground state of TbFe4.4 Al7.6 with Tb atoms contributing ferromagnetically (5.87μB) and Fe atoms with antiferromagnetic contribution (2.67μB), in close agreement with the experimental observation., (© 2024 IOP Publishing Ltd.)- Published
- 2024
- Full Text
- View/download PDF
25. Proximity induced band gap opening in topological-magnetic heterostructure (Ni 80 Fe 20 /p-TlBiSe 2 /p-Si) under ambient condition.
- Author
-
Singh R, Maurya GK, Gautam V, Kumar R, Kumar M, Suresh KG, Panigrahi B, Murapaka C, Haldar A, and Kumar P
- Abstract
The broken time reversal symmetry states may result in the opening of a band gap in TlBiSe
2 leading to several interesting phenomena which are potentially relevant for spintronic applications. In this work, the quantum interference and magnetic proximity effects have been studied in Ni80 Fe20 /p-TlBiSe2 /p-Si (Magnetic/TI) heterostructure using physical vapor deposition technique. Raman analysis shows the symmetry breaking with the appearance of A2 1u mode. The electrical characteristics are investigated under dark and illumination conditions in the absence as well as in the presence of a magnetic field. The outcomes of the examined device reveal excellent photo response in both forward and reverse bias regions. Interestingly, under a magnetic field, the device shows a reduction in electrical conductivity at ambient conditions due to the crossover of weak localization and separation of weak antilocalization, which are experimentally confirmed by magnetoresistance measurement. Further, the photo response has also been assessed by the transient absorption spectroscopy through analysis of charge transfer and carrier relaxation mechanisms. Our results can be beneficial for quantum computation and further study of topological insulator/ferromagnet heterostructure and topological material based spintronic devices due to high spin orbit coupling along with dissipationless conduction channels at the surface states., (© 2023. The Author(s).)- Published
- 2023
- Full Text
- View/download PDF
26. Unveiling the correlation between structural and magnetic ordering in nano Co 1- x Ni x TeO 4 .
- Author
-
Patel AK, Samatham SS, Rani E, Suresh KG, and Singh H
- Abstract
Nanomaterials with unique structures and exotic magnetic phenomena are always intriguing; however, the direct correlation of structural and magnetic ordering up to a few nanometers remains critical. We report structural and magnetic properties of sol-gel grown Co
1- x Nix TeO4 ( x = 0, 0.5 and 1) nanoparticles. An increase in the calcination temperature leads to the enhancement of the particle size and structural ordering. This is accompanied by changes in the magnetic interactions as well. Calcination at lower temperatures retains the short-range non-crystalline structure and superparamagnetic behavior, while calcination at higher temperatures results in long-range ordering in both the crystal and magnetic structures. Superparamagnetic to antiferromagnetic ordering observed from temperature- and field-dependent magnetization is attributed to the changes in structural ordering. This study presents a new family of nanomaterials displaying stable magnetic order up to ∼6 nm, where the magnetic properties can be uniquely controlled by changing the structural ordering.- Published
- 2023
- Full Text
- View/download PDF
27. Nearly compensated ferrimagnetic behaviour and giant exchange bias of hexagonal Mn 2 PtAl: experimental and theoretical studies.
- Author
-
Patel AK, Samatham SS, Lukoyanov AV, Babu PD, and Suresh KG
- Abstract
We have investigated the Mn
2 PtAl Heulser alloy to unravel its structural, magnetic, calorimetric and electronic structure properties. At room temperature, the alloy crystallizes in a hexagonal structure. Magnetization reveals a weak martensitic transition at 307 K, followed by a long range ferrimagnetic transition at 90 K. Griffiths phase-like signature and positive Weiss temperature in dc-magnetization, isothermal magnetic hysteresis loops and a frequency-independent peak confirm a nearly compensated ferrimagnetic order of Mn2 PtAl. The theoretical electronic structure calculations also reveal the ferrimagnetic ground state of Mn2 PtAl and Mn ions (occupying different sites) with a very small total magnetic moment. A giant exchange bias field of 2.73 kOe, at a temperature of 3 K and a cooling field of 70 kOe, has been estimated and is attributed to the unidirectional anisotropy associated with possible ferromagnetic clusters formed by the field cooling process in the ferrimagnetic matrix.- Published
- 2022
- Full Text
- View/download PDF
28. Magnetic behavior of Ru substituted skyrmion metal MnSi.
- Author
-
Samatham SS, Singh S, Patel AK, Shravan Kumar Reddy S, Takeuchi T, and Suresh KG
- Abstract
We report on the structural and magnetic properties of Ru substituted skyrmion metal MnSi i.e. Mn1-xRu
x Si for the nominal compositions of0⩽x⩽0.5. The composition-temperature ( x-T ) phase diagram illustrates the substitution-driven changes in the magnetic behavior. It is confirmed that the magnetic ordering temperature (para-to helimagnetic)Ttrand the effective magneticμeffmoment decrease with increasing x . This indicates the suppression of magnetic order by the substitution of Ru in MnSi. However, the magnetic nature is sustained up to a concentration of about x = 0.1 above which the system exhibits spin-glass like nature as inferred from the negative Curie-Weiss temperatureθCW, reduced magnetic moment (of the order 10-2 μBf.u.-1) and linear M-H (at 2 K) in x = 0.5. Mn1-xRux Si is found to avoid the quantum phase transition and exhibits a composition-driven magnetic to spin-glass like transition., (© 2022 IOP Publishing Ltd.)- Published
- 2022
- Full Text
- View/download PDF
29. Non-collinear antiferromagnetism to compensated ferrimagnetism in Ti(Fe 1- x Co x ) 2 ( x = 0, 0.5 and 1) alloys: experiment and theory.
- Author
-
Samatham SS, Patel AK, Lukoyanov AV, Suresh KG, and Nirmala R
- Abstract
The manifestation of the structural and magnetic properties of Co substituted TiFe2 is investigated using powder X-ray diffraction, magnetization and density functional theory calculations. The alloys TiFe2 and TiFeCo crystallize in the hexagonal structure (P63/mmc) with a reduction in the lattice parameters of TiFeCo (by about 0.51% in a and 0.64% in c) when compared to TiFe2. On the other hand, TiCo2 crystallizes in the cubic structure (Fd3[combining macron]m). A structural transition from hexagonal to cubic is anticipated for a composition with x ∈ [0.5, 1]. The non-collinear antiferromagnetic (AFM) spin structure (formed by 6h Fe atoms) of TiFe2 with Néel temperature TN ∼ 275 K is reported at zero magnetic field H. Meanwhile, a magnetic field-induced collinear antiferromagnetic spin structure is suggested by magnetization measurements and supported by density functional theory calculations. The magnetization of TiFeCo shows a weak-ferromagnetic (FM)-like transition around 204 K, followed by a broad hump at 85.5 K and H = 200 Oe. Ferromagnetic interactions are weakened, causing the hump to disappear due to the possible transfer of electrons between Fe and Co. TiCo2 shows compensated ferrimagnetism with magnetization of the order of 10-5μB f.u.-1 and a linear increase of M with H at 5 K. The presence of a non-collinear AFM spin structure in TiFe2, a reduced magnetic moment in TiFeCo due to the charge transfer between Co and Fe, and compensated ferrimagnetism in TiCo2 promise a rich phase diagram of Ti(Fe1-xCox)2 alloys and the possible potential of these alloys for use in spintronics applications.
- Published
- 2021
- Full Text
- View/download PDF
30. Effect of Electronic Correlations on the Electronic Structure, Magnetic and Optical Properties of the Ternary RCuGe Compounds with R = Tb, Dy, Ho, Er.
- Author
-
Lukoyanov AV, Gramateeva LN, Knyazev YV, Kuz'min YI, Gupta S, and Suresh KG
- Abstract
In this study, the ab initio and experimental results for RCuGe ternary intermetallics were reported for R = Tb, Dy, Ho, Er. Our theoretical calculations of the electronic structure, employing local spin density approximation accounting for electron-electron correlations in the 4f shell of Tb, Dy, Ho, Er ions were carried in DFT+U method. The optical properties of the RCuGe ternary compounds were studied at a broad range of wavelengths. The spectral and electronic characteristics were obtained. The theoretical electron densities of states were taken to interpret the experimental energy dependencies of the experimental optical conductivity in the interband light-absorption region. From the band calculations, the 4f shell of the rare-earth ions was shown to provide the major contribution to the electronic structure, magnetic and optical properties of the RCuGe intermetallics. The accounting for electron-electron correlations in Tb, Dy, Ho, Er resulted in a good agreement between the calculated and experimental magnetic and optical characteristics.
- Published
- 2020
- Full Text
- View/download PDF
31. Magnetism of 3d and 4d doped Mn 0.7 T 0.3 NiGe (T = Fe, Co, Ru and Rh): bulk magnetization and ab initio calculations.
- Author
-
Samatham SS, Patel AK, Lukoyanov AV, Baglasov ED, and Suresh KG
- Abstract
We compare the magnetic properties of 3d (Fe and Co) and 4d (Ru and Rh) transition metals doped MnNiGe using the combined results of magnetization and ab initio calculations. The alloys crystallize in austenite Ni
2 In-type hexagonal phase (space group: P63 /mmc) with insignificant difference in the lattice parameters. Mn0.7 Fe0.3 NiGe and Mn0.7 Co0.3 NiGe exhibit spin-glass behavior, resulting from the competing ferro- and antiferromagnetic interactions. These alloys exhibit spontaneous exchange bias field of about [Formula: see text] Oe and 323 Oe, respectively. From the 4d-metal doped alloys, Mn0.7 Ru0.3 NiGe shows glassy behavior while long-range ferromagnetic order is confirmed in Mn0.7 Rh0.3 NiGe. In Mn0.7 Rh0.3 NiGe, in agreement with experiment and the theoretical calculations, the ground state is confirmed to be ferromagnetic because of the FM exchange interactions of the Mn magnetic moments. But in Mn1-x (Fe,Co,Ru)x NiGe alloys the calculations revealed the competing and comparable FM and AFM exchange interaction parameters, resulting in the formation of spin-glassy characteristics.- Published
- 2019
- Full Text
- View/download PDF
32. Revelation of spin glass behavior in Ru doped MnNiGe: experiment and theory.
- Author
-
Samatham SS, Patel AK, Lukoyanov AV, and Suresh KG
- Abstract
We report on the nature of the magnetism in Ru substituted MnNiGe using the combined results of x-ray diffraction, dc-magnetization, ac-susceptibility and ab initio calculations. Mn
0.7 Ru0.3 NiGe crystallizes in Ni2 In-type hexagonal structure (P63 /mmc) at room temperature with lattice parameters a = b = 4.099 [Formula: see text] and c = 5.367 [Formula: see text]. From the dc-magnetization; a broad peak around 46.55 K, separation between zero-field cooled and field-cooled warming state and non-saturating isothermal magnetization with typical S-type hysteresis indicate glassy behavior. A cusp in [Formula: see text] is observed to shift toward high temperatures with increasing frequency. Mydosh parameter ([Formula: see text]), single-relaxation time ([Formula: see text] s) obtained through critical slowing-down analysis, [Formula: see text] from the Vogel-Fulcher law and Tholence criterion [Formula: see text], confirm that Mn0.7 Ru0.3 NiGe belongs to the short-range interaction spin-glass systems with strong coupling between the magnetic clusters. LSDA+U calculations confirmed the competing exchange interactions between large magnetic moments of the Mn ions in Mn0.7 Ru0.3 NiGe compound resulting in the formation of spin-glassy characteristics.- Published
- 2019
- Full Text
- View/download PDF
33. Magnetization, resistivity, specific heat and ab initio calculations of Gd 5 Sb 3 .
- Author
-
Samatham SS, Patel AK, Lukoyanov AV, and Suresh KG
- Abstract
We report on the combined results of the structural, magnetic, transport and calorimetric properties of Mn
5 Si3 -type hexagonal Gd5 Sb3 , together with ab initio calculations. It exhibits a ferromagnetic (FM)-like transition at 265 K, antiferromagnetic (AFM) Néel transition at 95.5 K followed by a spin-orientation transition at 62 K. The system is found to be in AFM state down to 2 K in a field of 70 kOe. The FM-AFM phase coexistence is not noticeable despite large positive Curie-Weiss temperature ([Formula: see text] K). Instead, low-temperature AFM and high-temperature FM-like phases are separated in large temperatures. Temperature-magnetic field (H-T) phase diagram reveals field-driven complex magnetic phases. Within the AFM phase, the system is observed to undergo field-driven spin-orientation transitions. Field-induced tricritical and quantum critical points appear to be absent due to the strong AFM nature and by the intervention of FM-like state between paramagnetic and AFM states, respectively. The metallic behavior of the compound is inferred from resistivity along with large Sommerfeld parameter. However, no sign of strong electron-correlations is reasoned from the Kadowaki-Wood's ratio [Formula: see text] [Formula: see text] cm · (mol · K)2 (mJ)-2 , despite heavy γ. Essentially, ab initio calculations accounting for electronic correlations confirm AFM nature of low-temperature magnetic state in Gd5 Sb3 and attainable FM ordering in agreement with experimental data.- Published
- 2018
- Full Text
- View/download PDF
34. Critical exponents and universal magnetic behavior of noncentrosymmetric Fe 0.6 Co 0.4 Si.
- Author
-
Samatham SS and Suresh KG
- Abstract
The critical magnetic properties of a non-centrosymmetric B20 cubic helimagnet Fe
0.6 Co0.4 Si are investigated using magnetization isotherms. It belongs to the 3D-Heisenberg universality class with short range magnetic coupling as inferred from the self-consistent critical exponents [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] in combination with exchange interaction [Formula: see text]. Itinerant magnetic nature of the compound is realized by the Rhodes-Wholfarth analysis. Field-induced weak first (para[Formula: see text]helical) to second (para[Formula: see text]field-polarized) order transition is reported to occur at low critical field due to the weak spin-orbit coupling arising from the weak Dzyaloshinksii-Moriya interactions. Our study suggests the distinct phenomenological magnetic structures for Fe-based cubic magnets (Fe1-x Cox Si and FeGe) and MnSi which cause contrasting physical properties.- Published
- 2018
- Full Text
- View/download PDF
35. Quantum phase transition and non-Fermi liquid behavior in Fe 1-x Co x Si (x ⩾ 0.7).
- Author
-
Samatham SS, Suresh KG, and Ganesan V
- Abstract
We report on the nature of electron correlations in Fe
1-x Cox Si ([Formula: see text]) using combined results of magnetization, specific heat and transport properties. Doping driven quantum critical point is observed to occur at [Formula: see text]. The magnetically unstable regime is identified to be centered around [Formula: see text] [[Formula: see text]]. The emergence of non-Fermi liquid behaviors in x = 0.8 (near to ferromagnetic quantum critical point) and x = 0.9 (disorder-induced) compositions are discussed on the basis of the power-law dependence of susceptibility [Formula: see text] ([Formula: see text] for x = 0.8 and 0.55 for x = 0.9), specific heat [Formula: see text] ([Formula: see text] for x = 0.8 and 0.9) and resistivity [Formula: see text] ([Formula: see text] for x = 0.8 and 1.38 for x = 0.9). Further, a comprehensive classification of doping dependent physical properties of Fe1-x Cox Si is presented in the revisited temperature-composition (T-x) phase diagram.- Published
- 2018
- Full Text
- View/download PDF
36. Observation of short range ferromagnetic interactions and magnetocaloric effect in cobalt substituted Gd 5 Si 2 Ge 2 .
- Author
-
Uthaman B, Manju P, Thomas S, Jaiswal Nagar D, Suresh KG, and Varma MR
- Abstract
We report on the observation of double transition - a first order and a second order transition in Gd
5 Si2-x Cox Ge2 with x = 0, 0.1, 0.2 and 0.4 with the appearance of short-range ferromagnetic correlations. The first order phase transition is due to a combined magnetostructural transition from monoclinic paramagnetic phase to orthorhombic ferromagnetic phase on cooling while the second order transition arises from an orthorhombic paramagnetic to ferromagnetic phase on cooling. Structural studies show that the substituted compounds crystallize in a combination of Gd5 Si2 Ge2 and Gd5 Si4 phases. Low-temperature X-ray diffraction measurements confirm the complete transformation from monoclinic to orthorhombic phase. DC magnetization measurements reveal an anomalous low field magnetic behaviour indicating a Griffiths-like phase. This unusual behaviour is attributed to the local disorder within the crystallographic structure indicating the presence of short-range magnetic correlations and ferromagnetic clustering, which is stabilized and enhanced by competing intra-layer and inter-layer magnetic interactions. The magnetostructural transition results in entropy changes (-ΔSM ) of 9 J kg-1 K-1 at 260 K for x = 0.1, 8.5 J kg-1 K-1 at 245 K for x = 0.2 and 4.2 J kg-1 K-1 at 210 K for x = 0.4 for a field change of 50 kOe. Co substitution induces compelling crystallographic and magnetoresponsive effects in the Gd-Si-Ge system, which could be useful for potential and smart applications such as solid-state magnetic refrigeration and sensitive magnetic switching from paramagnetic to ferromagnetic state. Universal curve analysis has been carried out on the substituted samples to study the order of the magnetic transition.- Published
- 2017
- Full Text
- View/download PDF
37. Genetic diversity of caprine Blastocystis from Peninsular Malaysia.
- Author
-
Tan TC, Tan PC, Sharma R, Sugnaseelan S, and Suresh KG
- Subjects
- Animals, Blastocystis isolation & purification, Blastocystis Infections epidemiology, Blastocystis Infections parasitology, Female, Genotype, Goats, Malaysia epidemiology, Male, Molecular Epidemiology, Polymerase Chain Reaction, Prevalence, Blastocystis classification, Blastocystis genetics, Blastocystis Infections veterinary, Genetic Variation, Goat Diseases epidemiology, Goat Diseases parasitology
- Abstract
Blastocystis sp. is a common intestinal parasite found in humans and animals. The possibility of zoonotic transmission to humans from livestock especially goats led us to investigate the genetic diversity of caprine Blastocystis sp. obtained from five different farms in Peninsular Malaysia. Moreover, there is a lack of information on the prevalence as well as genetic diversity of Blastocystis sp. in goat worldwide. Results showed that 73/236 (30.9 %) of the goats were found to be positive for Blastocystis infection. The most predominant Blastocystis sp. subtype was ST1 (60.3 %) followed by ST7 (41.1 %), ST6 (41.1 %), and ST3 (11.0 %) when amplified by PCR using sequenced-tagged site (STS) primers. Four farms had goats infected only with ST1 whereas the fifth showed mixed infections with multiple STs. The proximity of the fifth farm to human dwellings, nearby domesticated animals and grass land as opposed to a sterile captive environment in the first four farms may account for the multiple STs seen in the fifth farm. Since ST1, ST3, ST6 and ST 7 were previously reported in human infection worldwide in particular Malaysia, the potential of the zoonotic transmission of blastocystosis should not be disregarded. The implications of different farm management systems on the distribution of Blastocystis sp. STs are discussed.
- Published
- 2013
- Full Text
- View/download PDF
38. Apoptosis in Blastocystis spp. is related to subtype.
- Author
-
Dhurga DB, Suresh KG, Tan TC, and Chandramathi S
- Subjects
- Animals, Apoptosis physiology, Blastocystis cytology, Blastocystis isolation & purification, Blastocystis Infections drug therapy, Drug Resistance physiology, Humans, Microscopy, Fluorescence, Species Specificity, Staining and Labeling, Antiprotozoal Agents pharmacology, Apoptosis drug effects, Blastocystis drug effects, Blastocystis Infections parasitology, Metronidazole pharmacology
- Abstract
Previous studies have shown that apoptosis-like features are observed in Blastocystis spp., an intestinal protozoan parasite, when exposed to the cytotoxic drug metronidazole (MTZ). This study reports that among the four subtypes of Blastocystis spp. investigated for rate of apoptosis when treated with MTZ, subtype 3 showed the highest significant increase after 72h of in vitro culture when treated with MTZ at 0.1mg/ml (79%; p<0.01) and 0.0001mg/ml (89%; p<0.001). The close correlation between viable cells and apoptotic cells for both dosages implies that the pathogenic potential of these isolates has been enhanced when treated with MTZ. This suggests that there is a mechanism in Blastocystis spp. that actually regulates the apoptotic process to produce higher number of viable cells when treated. Apoptosis may not just be programmed cell death but instead a mechanism to increase the number of viable cells to ensure survival during stressed conditions. The findings of the present study have an important contribution to influence chemotherapeutic approaches when developing drugs against the emerging Blastocystis spp. infections., (Copyright © 2012 Royal Society of Tropical Medicine and Hygiene. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2012
- Full Text
- View/download PDF
39. A small molecule inhibitor of ubiquitin-specific protease-7 induces apoptosis in multiple myeloma cells and overcomes bortezomib resistance.
- Author
-
Chauhan D, Tian Z, Nicholson B, Kumar KG, Zhou B, Carrasco R, McDermott JL, Leach CA, Fulcinniti M, Kodrasov MP, Weinstock J, Kingsbury WD, Hideshima T, Shah PK, Minvielle S, Altun M, Kessler BM, Orlowski R, Richardson P, Munshi N, and Anderson KC
- Subjects
- Animals, Antineoplastic Agents therapeutic use, Antineoplastic Combined Chemotherapy Protocols pharmacology, Antineoplastic Combined Chemotherapy Protocols therapeutic use, Boronic Acids therapeutic use, Bortezomib, Cell Line, Tumor, Cyclin-Dependent Kinase Inhibitor p21 antagonists & inhibitors, Dexamethasone pharmacology, Dexamethasone therapeutic use, Drug Resistance, Neoplasm drug effects, Drug Therapy, Combination, Humans, Lenalidomide, Mice, Mice, SCID, Molecular Sequence Data, Multiple Myeloma enzymology, Multiple Myeloma pathology, Neovascularization, Pathologic drug therapy, Protease Inhibitors pharmacology, Protease Inhibitors therapeutic use, Proto-Oncogene Proteins c-mdm2 metabolism, Pyrazines therapeutic use, Random Allocation, Thalidomide analogs & derivatives, Thalidomide pharmacology, Thalidomide therapeutic use, Thiophenes therapeutic use, Ubiquitin Thiolesterase genetics, Ubiquitin-Specific Peptidase 7, Xenograft Model Antitumor Assays, Antineoplastic Agents pharmacology, Apoptosis drug effects, Boronic Acids pharmacology, Multiple Myeloma drug therapy, Pyrazines pharmacology, Thiophenes pharmacology, Ubiquitin Thiolesterase antagonists & inhibitors
- Abstract
Bortezomib therapy has proven successful for the treatment of relapsed/refractory, relapsed, and newly diagnosed multiple myeloma (MM); however, dose-limiting toxicities and the development of resistance limit its long-term utility. Here, we show that P5091 is an inhibitor of deubiquitylating enzyme USP7, which induces apoptosis in MM cells resistant to conventional and bortezomib therapies. Biochemical and genetic studies show that blockade of HDM2 and p21 abrogates P5091-induced cytotoxicity. In animal tumor model studies, P5091 is well tolerated, inhibits tumor growth, and prolongs survival. Combining P5091 with lenalidomide, HDAC inhibitor SAHA, or dexamethasone triggers synergistic anti-MM activity. Our preclinical study therefore supports clinical evaluation of USP7 inhibitor, alone or in combination, as a potential MM therapy., (Copyright © 2012 Elsevier Inc. All rights reserved.)
- Published
- 2012
- Full Text
- View/download PDF
40. The role of worm infestation in allergic rhinitis.
- Author
-
Manuel AM, Kuljit S, Gopalakrishnan G, Suresh KG, and Balraj P
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Animals, Antigens, Helminth blood, Case-Control Studies, Child, Enzyme-Linked Immunosorbent Assay, Humans, Immunoglobulin E blood, Immunoglobulin G blood, Incidence, Larva Migrans, Visceral complications, Larva Migrans, Visceral epidemiology, Longitudinal Studies, Middle Aged, Occupations, Prevalence, Prospective Studies, Rhinitis, Allergic, Rhinitis, Allergic, Perennial parasitology, Young Adult, Larva Migrans, Visceral parasitology, Rhinitis, Allergic, Perennial immunology, Toxocara canis immunology
- Abstract
The purpose of this study is to determine the relevance of the hygiene hypothesis; that is to determine if worm infestation has a protective role against the development of allergic rhinitis. A prospective case controlled study was conducted. Specific IgG levels to Toxocara were studied in 85 patients confirmed to have allergic rhinitis and were compared to levels in another 85 controls, with no form of allergy. The IgG assay was done using ELISA technique. There was a higher incidence of positive specific IgG to Toxocara in the controls as compared to allergic patients. The values were statistically significant [Chi square test (p=0.002)]. This negative association between worm infestation and allergic rhinitis suggests that a previous worm infestation could protect against the development of allergic rhinitis.
- Published
- 2012
41. Predominance of Blastocystis sp. subtype 4 in rural communities, Nepal.
- Author
-
Lee IL, Tan TC, Tan PC, Nanthiney DR, Biraj MK, Surendra KM, and Suresh KG
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Animals, Child, Child, Preschool, Cross-Sectional Studies, DNA Primers isolation & purification, DNA, Protozoan isolation & purification, Feces parasitology, Female, Genotype, Humans, Infant, Male, Middle Aged, Nepal epidemiology, Rural Population, Sequence Analysis, DNA methods, Sequence Tagged Sites, Young Adult, Blastocystis isolation & purification, Blastocystis parasitology, Blastocystis Infections epidemiology, Blastocystis Infections parasitology
- Abstract
Blastocystis sp. is a common intestinal parasite. To date, there have been sporadic and scanty studies on Blastocystis sp. carried out in rural communities in Nepal. We surveyed the prevalence of Blastocystis sp. and its possible associated risk factors, and reported the predominant Blastocystis sp. subtype in two rural communities, Bolde Phediche and Bahunipati, in Nepal. Human faecal samples were collected from 241 participants, cultured using in vitro cultivation and examined for Blastocystis sp. The presence of Blastocystis sp. in faecal samples was further confirmed by polymerase chain reaction (PCR) and subsequently genotyped using subtype-specific sequence tagged site (STS) primers. There were 26.1% (63/241) of the participants that were infected by Blastocystis sp. We detected 84.1% (53/63) of Blastocystis sp. subtype 4 infections in these rural communities. The unusually high prevalence of Blastocystis sp. subtype 4 can be attributed to the rearing of family-owned animals in barns built close to their houses. Eighty one percent (51/63) of the Blastocystis sp. infected participants drank not boiled or unfiltered water. The present study revealed that Blastocystis sp. could pose a health concern to the communities and travellers to the hilly area in Nepal. Infection may be transmitted through human-to-human, zoonotic and waterborne transmissions. We provide recommendations to ensure good public health practices.
- Published
- 2012
- Full Text
- View/download PDF
42. Low temperature cluster glass behavior in Nd5Ge3.
- Author
-
Maji B, Suresh KG, and Nigam AK
- Abstract
Various experimental evidence obtained from dc and ac magnetization measurements indicates that Nd(5)Ge(3) undergoes a spin glass transition from a high temperature antiferromagnetic state. Below the Néel temperature of 49 K, it shows distinct properties that characterize a cluster glass state, thereby indicating that it is an example of a reentrant spin glass system. Dynamical behavior of the magnetic susceptibility and the magnetic relaxation clearly give evidence of frustration in the material. Geometric frustration arising from the triangular arrangement of Nd atoms seems to be the main reason behind the spin glass state. A field-induced structural distortion accompanying the Néel transition may also be responsible for the frustration and the spin glass state., (© 2011 IOP Publishing Ltd Printed in the UK & the USA)
- Published
- 2011
- Full Text
- View/download PDF
43. Activity-based chemical proteomics accelerates inhibitor development for deubiquitylating enzymes.
- Author
-
Altun M, Kramer HB, Willems LI, McDermott JL, Leach CA, Goldenberg SJ, Kumar KG, Konietzny R, Fischer R, Kogan E, Mackeen MM, McGouran J, Khoronenkova SV, Parsons JL, Dianov GL, Nicholson B, and Kessler BM
- Subjects
- Aminopyridines chemistry, Antibodies chemistry, Antibodies immunology, Cell Line, Chromatography, High Pressure Liquid, Enzyme Activation drug effects, Enzyme Inhibitors chemistry, Humans, RNA Interference, Tandem Mass Spectrometry, Thiocyanates chemistry, Thiophenes chemistry, Ubiquitin Thiolesterase immunology, Ubiquitin Thiolesterase metabolism, Ubiquitin-Specific Peptidase 7, Aminopyridines pharmacology, Enzyme Inhibitors pharmacology, Proteomics, Thiocyanates pharmacology, Thiophenes pharmacology, Ubiquitin Thiolesterase antagonists & inhibitors
- Abstract
Converting lead compounds into drug candidates is a crucial step in drug development, requiring early assessment of potency, selectivity, and off-target effects. We have utilized activity-based chemical proteomics to determine the potency and selectivity of deubiquitylating enzyme (DUB) inhibitors in cell culture models. Importantly, we characterized the small molecule PR-619 as a broad-range DUB inhibitor, and P22077 as a USP7 inhibitor with potential for further development as a chemotherapeutic agent in cancer therapy. A striking accumulation of polyubiquitylated proteins was observed after both selective and general inhibition of cellular DUB activity without direct impairment of proteasomal proteolysis. The repertoire of ubiquitylated substrates was analyzed by tandem mass spectrometry, identifying distinct subsets for general or specific inhibition of DUBs. This enabled identification of previously unknown functional links between USP7 and enzymes involved in DNA repair., (Copyright © 2011 Elsevier Ltd. All rights reserved.)
- Published
- 2011
- Full Text
- View/download PDF
44. Correlation between reentrant spin glass behavior and the magnetic order-disorder transition of the martensite phase in Ni-Co-Mn-Sb Heusler alloys.
- Author
-
Nayak AK, Suresh KG, and Nigam AK
- Abstract
We have performed ac susceptibility and dc magnetization measurements in Ni(50-x)Co(x)Mn(38)Sb(12) Heusler alloys. From the ac susceptibility measurements, the existence of reentrant spin glass (RSG) state is observed for x=0-5. It is found that the signature of RSG behavior diminishes with increase in x. This behavior is in contrast to the fact that the exchange bias field increases with x, which reveals that the origins of RSG and exchange bias are different in the present system. It is found that the system enters a frustrated ferromagnetic state just below the Curie temperature of the martensite phase (T(M)(C)) and then the RSG state at low temperature. The strength of the RSG state is critically dependent on the sharpness of the magnetic transition at (T(M)(C)). This proposition is further supported by the thermo-remanent magnetization and low field thermomagnetic measurements., (© 2011 IOP Publishing Ltd)
- Published
- 2011
- Full Text
- View/download PDF
45. Urinary hyaluronidase activity in rats infected with Blastocystis hominis--evidence for invasion?
- Author
-
Chandramathi S, Suresh KG, Mahmood AA, and Kuppusamy UR
- Subjects
- Animals, Blastocystis Infections diagnosis, Blastocystis Infections pathology, Cytokines blood, Feces parasitology, Rats, Sprague-Dawley, Blastocystis Infections veterinary, Blastocystis hominis enzymology, Hyaluronoglucosaminidase urine, Protozoan Proteins urine, Rats parasitology
- Abstract
The fact whether Blastocystis hominis can invade has always been in question. Apart from a few sporadic studies such as that done on gnotobiotic guinea pigs which showed surface invasion and mucosal inflammation of the host's intestine caused by B. hominis infection, no real documentation of invasion has been proven. Studies have shown that hyaluronidase is secreted during the penetration into the host's skin and gut by nematode parasites. Hyaluronidase activity in protozoa namely Entamoeba histolytica has also been described previously. This study attempts to determine hyaluronidase in urine samples of B. hominis-infected rats. The presence of hyaluronidase in urine provides an indirect evidence of invasion by B. hominis into colonic epithelium causing the degradation of extracellular matrix proteins namely hyaluronic acid (HA). HA is depolymerized by hyaluronidase which may be used by organisms to invade one another. In this study, the levels of urinary hyaluronidase of Sprague-Dawley rats infected with B. hominis were monitored for 30 days. Hyaluronidase levels in the infected rats were significantly higher on days 28 and 30 compared to the day before inoculation (P < 0.01 and P < 0.05, respectively). During this stage, parasitic burden in infected stools was also at a high level. Proinflammatory cytokines, interleukin-6 and interleukin-8, were also significantly higher (P < 0.05) in the serum of infected rats. The study demonstrates that since no other pathogen was present and that amoeboid forms of the parasites have been shown to exist previously, the elevated levels of hyaluronidase in this preliminary finding suggests that the organism is capable of having invasion or penetration activity in the hosts' intestine.
- Published
- 2010
- Full Text
- View/download PDF
46. Stabilization of antiferromagnetism in CeFe(2) alloys: the effects of chemical and hydrostatic pressure.
- Author
-
Haldar A, Suresh KG, Nigam AK, Coelho AA, and Gama S
- Abstract
Effects of Al, Mn and Sb dopings in CeFe(2) and the effect of applied pressure have been investigated. Al doping gives rise to the FM-AFM transition and a reduction in the magnetic moment and T(C) values, clearly indicating the growth of the AFM component. Mn and Sb dopings only cause a reduction in the T(C) value. It is found that, in general, external pressure enhances the antiferromagnetism in both the pure and the doped alloys. Enhancement of the Ce 4f-Fe 3d hybridization as a result of doping and with the external pressure may be the reason for the stabilization of antiferromagnetism in these alloys.
- Published
- 2009
- Full Text
- View/download PDF
47. Mammalian casein kinase 1alpha and its leishmanial ortholog regulate stability of IFNAR1 and type I interferon signaling.
- Author
-
Liu J, Carvalho LP, Bhattacharya S, Carbone CJ, Kumar KG, Leu NA, Yau PM, Donald RG, Weiss MJ, Baker DP, McLaughlin KJ, Scott P, and Fuchs SY
- Subjects
- Amino Acid Sequence, Animals, Casein Kinase Ialpha genetics, Cell Line, Humans, Molecular Sequence Data, Protein Isoforms genetics, Protozoan Proteins genetics, RNA, Small Interfering genetics, RNA, Small Interfering metabolism, Receptor, Interferon alpha-beta genetics, Casein Kinase Ialpha metabolism, Interferon Type I metabolism, Leishmania major enzymology, Protein Isoforms metabolism, Protozoan Proteins metabolism, Receptor, Interferon alpha-beta metabolism, Signal Transduction physiology
- Abstract
Phosphorylation of the degron of the IFNAR1 chain of the type I interferon (IFN) receptor triggers ubiquitination and degradation of this receptor and, therefore, plays a crucial role in negative regulation of IFN-alpha/beta signaling. Besides the IFN-stimulated and Jak activity-dependent pathways, a basal ligand-independent phosphorylation of IFNAR1 has been described and implicated in downregulating IFNAR1 in response to virus-induced endoplasmic reticulum (ER) stress. Here we report purification and characterization of casein kinase 1alpha (CK1alpha) as a bona fide major IFNAR1 kinase that confers basal turnover of IFNAR1 and cooperates with ER stress stimuli to mediate phosphorylation-dependent degradation of IFNAR1. Activity of CK1alpha was required for phosphorylation and downregulation of IFNAR1 in response to ER stress and viral infection. While many forms of CK1 were capable of phosphorylating IFNAR1 in vitro, human CK1alpha and L-CK1 produced by the protozoan Leishmania major were also capable of increasing IFNAR1 degron phosphorylation in cells. Expression of leishmania CK1 in mammalian cells stimulated the phosphorylation-dependent downregulation of IFNAR1 and attenuated its signaling. Infection of mammalian cells with L. major modestly decreased IFNAR1 levels and attenuated cellular responses to IFN-alpha in vitro. We propose a role for mammalian and parasite CK1 enzymes in regulating IFNAR1 stability and type I IFN signaling.
- Published
- 2009
- Full Text
- View/download PDF
48. Vertical fragment in adult midshaft clavicle fractures: an indicator for surgical intervention.
- Author
-
Kirmani SJ, Pillai SK, Madegowda BR, and Shahane SA
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Clavicle diagnostic imaging, Cohort Studies, Female, Fracture Healing, Fractures, Bone diagnostic imaging, Fractures, Malunited prevention & control, Fractures, Ununited prevention & control, Humans, Joint Dislocations diagnostic imaging, Joint Dislocations surgery, Male, Middle Aged, Radiography, Retrospective Studies, Time Factors, Treatment Outcome, Young Adult, Clavicle injuries, Fractures, Bone surgery, Postoperative Complications prevention & control
- Abstract
This article describes a retrospective cohort study that investigated whether adult midshaft clavicle fractures possessing the radiological sign of a butterfly vertical fragment demonstrate a higher rate of early and delayed surgical intervention when compared to adult midshaft clavicle fractures with no vertical fragment sign. The radiographs of 134 adult midshaft clavicle fractures were divided into 2 cohorts: those with a vertical fragment radiological sign and those without. Within each cohort, the number of cases that underwent early surgical intervention and that underwent delayed surgical intervention was noted. The vertical fragment group displayed a rate for early surgical intervention, all for skin tenting, of 8.5%, whereas the no vertical fragment group's rate was 1.1%; this proved to be significantly different (P=.0464). Furthermore, the vertical fragment group displayed a rate for delayed surgical intervention for symptomatic nonunion of 12.8%, whereas the no vertical fragment group's rate was 5.7%. Despite being twice as likely for the vertical fragment group to have undergone delayed surgical intervention, this did not prove to be statistically significant (P=.0965). This study revealed that midshaft fractures with the radiological sign of an interfragmentary vertical fragment are significantly more likely to require early surgical intervention due to skin tenting. Furthermore, these fractures are twice as likely to go into symptomatic nonunion, and in this area we may be able to improve current management by considering early surgical intervention.
- Published
- 2009
- Full Text
- View/download PDF
49. Genetic variability of Blastocystis sp. isolates obtained from cancer and HIV/AIDS patients.
- Author
-
Tan TC, Ong SC, and Suresh KG
- Subjects
- Animals, Blastocystis genetics, DNA Primers genetics, Genotype, Humans, Polymerase Chain Reaction methods, Blastocystis classification, Blastocystis isolation & purification, Blastocystis Infections parasitology, DNA, Protozoan genetics, HIV Infections complications, Neoplasms complications, Polymorphism, Genetic
- Abstract
This represents the first study to determine the genetic diversity of Blastocystis sp. among cancer and HIV/AIDS patients. Forty Blastocystis sp. isolates obtained from 20 cancer and 20 HIV/AIDS patients were genotyped by PCR using seven pairs of known sequenced-tagged site primers. Out of the 40 isolates, 38 were identified as one of the known genotypes and two isolates were negative with all the STS primers. Blastocystis sp. subtype 3 which is reported to be associated with disease was found to be predominant among the study subjects.
- Published
- 2009
- Full Text
- View/download PDF
50. Nuclearity control in molecular iron phosphates through choice of iron precursors and ancillary ligands.
- Author
-
Murugavel R, Gogoi N, Suresh KG, Layek S, and Verma HC
- Abstract
The potential of a mono-organophosphate ester in assembling low to medium nuclearity iron complexes with novel topological architectures has been investigated. Reaction of 2,6-diisopropylphenyl dihydrogen phosphate (dipp-H(2)) with ferrous acetate under an inert atmosphere resulted in the formation of mononuclear, [Fe(II)(dipp-H)(2)(py)(4)] (1) (py = pyridine), dinuclear [Fe(III) (2)O(dipp-H)(4)(3,5-dmpz)(3)(thf)](3,5-dmpz)(thf)(3) (2) (3,5-dmpz = 3,5-dimethylpyrazole, thf = tetrahydrofuran), and trinuclear [Fe(III) (2)Fe(II)O(dipp-H)(6)(thf)(3)](collidine) (3) complexes by changing the ancillary amine used in the reaction. Use of a preformed mu(3)-oxo bridged trinuclear complex, [Fe(III) (3)O(O(2)CR)(6)(H(2)O)(3)]X (X = Cl and NO(3)), as the precursor yielded two tetranuclear iron phosphates, [Fe(III) (4)O(dipp)(3)(py)(4)(PhCOO)(4)](toluene)(3) (4) and [Fe(III) (4)O(dipp)(3)(OAc)(4)(py)(4)](py)(2) (5), having a core structure similar to those found in tetranuclear iron phosphonates. When FeCl(3)6H(2)O was used as the iron precursor, an unprecedented pentanuclear iron phosphate complex, [Fe(III) (5)O(dipp)(6)(py)(4)Cl(2)][pyH] (6) with a novel structure was isolated. Another pentanuclear complex having a similar core structure, [Fe(5)O(dipp)(6)(HO(2)CPh)(3)(CH(3)CN)(3)Cl] (7) was isolated on treatment of dipp-H(2) with the triangular complex, [Fe(III) (3)O(O(2)CPh)(6)(H(2)O)(3)]Cl in the absence of any added amine co-ligand. Compounds 1-7 have been characterized by analytical techniques, spectroscopic studies, single crystal X-ray diffraction studies, and magnetic measurements. The Mössbauer studies carried out at room temperature support the formulation of all the compounds.
- Published
- 2009
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.