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Galgiani JN, Catanzaro A, Cloud GA, Johnson RH, Williams PL, Mirels LF, Nassar F, Lutz JE, Stevens DA, Sharkey PK, Singh VR, Larsen RA, Delgado KL, Flanigan C, Rinaldi MG. Comparison of oral fluconazole and itraconazole for progressive, nonmeningeal coccidioidomycosis. A randomized, double-blind trial. Mycoses Study Group. Ann Intern Med 2000; 133:676-86. [PMID: 11074900 DOI: 10.7326/0003-4819-133-9-200011070-00009] [Citation(s) in RCA: 162] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND In previous open-label noncomparative clinical trials, both fluconazole and itraconazole were effective therapy for progressive forms of coccidioidomycosis. OBJECTIVE To determine whether fluconazole or itraconazole is superior for treatment of nonmeningeal progressive coccidioidal infections. DESIGN Randomized, double-blind, placebo-controlled trial. SETTING 7 treatment centers in California, Arizona, and Texas. PATIENTS 198 patients with chronic pulmonary, soft tissue, or skeletal coccidioidal infections. INTERVENTION Oral fluconazole, 400 mg/d, or itraconazole, 200 mg twice daily. MEASUREMENTS After 4, 8, and 12 months, a predefined scoring system was used to assess severity of infection. Findings were compared with those at baseline. RESULTS Overall, 50% of patients (47 of 94) and 63% of patients (61 of 97) responded to 8 months of treatment with fluconazole and itraconazole, respectively (difference, 13 percentage points [95% CI, -2 to 28 percentage points]; P = 0.08). Patients with skeletal infections responded twice as frequently to itraconazole as to fluconazole. By 12 months, 57% of patients had responded to fluconazole and 72% had responded to itraconazole (difference, 15 percentage points [CI, 0.003 to 30 percentage points]; P = 0.05). Soft tissue disease was associated with increased likelihood of response, as in previous studies. Azole drug was detected in serum specimens from all but 3 patients; however, drug concentrations were not helpful in predicting outcome. Relapse rates after discontinuation of therapy did not differ significantly between groups (28% after fluconazole treatment and 18% after itraconazole treatment). Both drugs were well tolerated. CONCLUSIONS Neither fluconazole nor itraconazole showed statistically superior efficacy in nonmeningeal coccidioidomycosis, although there is a trend toward slightly greater efficacy with itraconazole at the doses studied.
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Sundar S, Jha TK, Thakur CP, Mishra M, Singh VR, Buffels R. Low-dose liposomal amphotericin B in refractory Indian visceral leishmaniasis: a multicenter study. Am J Trop Med Hyg 2002; 66:143-6. [PMID: 12135284 DOI: 10.4269/ajtmh.2002.66.143] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
In this randomized, double-blind, dose-ranging, multicenter trial, 84 patients with visceral leishmaniasis refractory to antimony therapy were administered liposomal amphotericin B (AmBisome) at cumulative doses of 3.75, 7.5, and 15.0 mg/kg for 5 consecutive days. Posttreatment apparent cure and definite cure were assessed at 2 weeks and 6 months after the end of therapy, respectively. Mild to moderate infusion-related fever and rigors were seen in 29 and 44% of patients, respectively. One patient each in the 3.75- and 7.5-mg groups had detectable parasites on splenic smear at posttreatment evaluation. At 6 months' follow-up, however, 2, 1, and 1 patients relapsed in the 3.75-, 7.5-, and 15.0-mg groups, resulting in definite cure rates of 89, 93, and 97%, respectively. There was no significant difference in the cure rates of the 3 groups. Low-dose liposomal amphotericin B given for 5 days can cure most patients with Indian kala-azar.
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Singh VR, Smith DK, Lawerence J, Kelly PC, Thomas AR, Spitz B, Sarosi GA. Coccidioidomycosis in patients infected with human immunodeficiency virus: review of 91 cases at a single institution. Clin Infect Dis 1996; 23:563-8. [PMID: 8879781 DOI: 10.1093/clinids/23.3.563] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
We retrospectively evaluated the clinical manifestations, diagnosis, treatment, and outcome of coccidioidomycosis in 91 patients infected with human immunodeficiency virus (HIV) at a single institution. Coccidioidomycosis was the AIDS-defining illness in 37 patients. Fever and chills, weight loss, and night sweats were the most frequent symptoms. The lung was the most frequently involved organ (80%), followed by the meninges (15%). A diffuse reticulonodular infiltrate was seen in 59 patients (65%), and 13 (14%) had focal pulmonary disease; for 15 patients (16%), the chest radiograph was normal. Coccidioidal serologies were positive for 60 patients (68%), while for 23% with proven coccidioidomycosis such tests were negative Most patients were treated with systemic amphotericin B and then an oral azole. The mortality for the whole group was 60%. Patients with diffuse pulmonary disease had the highest mortality (68%), with a median duration of survival of 54 days (P < .05; 95% confidence interval, 147-175 days). The presence of diffuse pulmonary disease and a CD4 lymphocyte count of < 50/microL were independent predictors of death. In our experience, coccidioidomycosis is an important opportunistic infection that causes substantial morbidity and mortality among HIV-infected patients living in an area of endemicity.
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Blue SR, Singh VR, Saubolle MA. Bacillus licheniformis bacteremia: five cases associated with indwelling central venous catheters. Clin Infect Dis 1995; 20:629-33. [PMID: 7756487 DOI: 10.1093/clinids/20.3.629] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Bacillus species are being more frequently recognized as pathogens in immunocompromised hosts or in patients with cancer and central venous catheters. Only nine cases of Bacillus licheniformis infection have been reported in the English-language literature since 1966. In a retrospective study we describe six patients and 17 episodes of B. licheniformis bacteremia over a 5-year span. All six patients had either a Hickman or a Broviac catheter in place for more than 3 months. Five of the six patients had multiple clinically significant episodes of bacteremia due to B. licheniformis. The six patients ranged in age from 4 years to 62 years. Two patients had leukemia or lymphoma and three patients had solid tumors, but only one patient was neutropenic. No deaths were related to B. licheniformis bacteremia. B. licheniformis should be considered as a potential pathogen in immunocompromised patients, especially when bacteremia is associated with the presence of long-term central venous catheters. Mortality due to B. licheniformis bacteremia is low, but recurrent bacteremia due to this organism causes significant morbidity and usually necessitates removal of the catheter.
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Singh VR, Yadav S, Adya VP. Role of natural frequency of bone as a guide for detection of bone fracture healing. JOURNAL OF BIOMEDICAL ENGINEERING 1989; 11:457-61. [PMID: 2682001 DOI: 10.1016/0141-5425(89)90039-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The natural frequency of bone is studied in normal and fractured bones, in vitro as well as in vivo, by recording the outputs of microphone pick-ups, attached at proximal and distal ends to the bone defect. Natural frequency of bone is determined for an optimum output displayed on a cathode ray oscilloscope with respect to different stress wave frequencies. A comparative study of normal and fractured bone in vivo in 25 patients was made to diagnose the size of the fracture and its rate of healing. The natural frequency and intensity of sound in the injured bone was reduced while the output voltage increased with respect to the normal bone. The investigation reports a simple, reliable and rapid technique for the assessment of bone fracture.
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Singh VR, Adya VP, Ahmed A, Yadav S. A stress wave propagation technique for bone repair study. IEEE Trans Biomed Eng 1990; 37:1014-7. [PMID: 2249860 DOI: 10.1109/10.102815] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The diagnosis of bone fracture and its rate of healing still remains a problem among orthopedic surgeons. An acoustic technique based on stress-wave propagation is developed. The technique is used on laboratory experimental in vitro bones, as well as on in vivo (human) bones, to diagnose a fracture. The rate of healing of the fracture is also studied. The technique developed is quick, economical, reliable, portable, and safe for both the patient and the operator.
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Rajapitamahuni A, Zhang L, Koten MA, Singh VR, Burton JD, Tsymbal EY, Shield JE, Hong X. Giant Enhancement of Magnetic Anisotropy in Ultrathin Manganite Films via Nanoscale 1D Periodic Depth Modulation. PHYSICAL REVIEW LETTERS 2016; 116:187201. [PMID: 27203341 DOI: 10.1103/physrevlett.116.187201] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Indexed: 06/05/2023]
Abstract
The relatively low magnetocrystalline anisotropy (MCA) in strongly correlated manganites (La,Sr)MnO_{3} has been a major hurdle for implementing them in spintronic applications. Here we report an unusual, giant enhancement of in-plane MCA in 6 nm La_{0.67}Sr_{0.33}MnO_{3} (LSMO) films grown on (001) SrTiO_{3} substrates when the top 2 nm is patterned into periodic stripes of 100 or 200 nm width. Planar Hall effect measurements reveal an emergent uniaxial anisotropy superimposed on one of the original biaxial easy axes for unpatterned LSMO along ⟨110⟩ directions, with a 50-fold enhanced anisotropy energy density of 5.6×10^{6} erg/cm^{3} within the nanostripes, comparable to the value for cobalt. The magnitude and direction of the uniaxial anisotropy exclude shape anisotropy and the step edge effect as its origin. High resolution transmission electron microscopy studies reveal a nonequilibrium strain distribution and drastic suppression in the c-axis lattice constant within the nanostructures, which is the driving mechanism for the enhanced uniaxial MCA, as suggested by first-principles density functional calculations.
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Bhatia KG, Singh VR. Ultrasonic characteristics of leiomyoma uteri in vitro. ULTRASOUND IN MEDICINE & BIOLOGY 2001; 27:983-987. [PMID: 11476932 DOI: 10.1016/s0301-5629(01)00364-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Patients suffer with various abnormalities of body tissues. "Leiomyoma Uteri" is a solid tumor of uterus, one of such abnormalities. To treat such tumors, basic physical and biologic investigations are required to be carried out. In the present work, ultrasonic characterization of soft tissues, in this case, uterine tumor in vitro, are studied. A double probe through-transmission technique is used for the measurement of these propagation parameters, viz., velocity and attenuation. Other parameters like acoustic impedance, dynamic modulus of elasticity and compressibility are also determined. The average velocity and attenuation are found to be 1550 ms(-1) and 433 dBm(-1), respectively, at 3.5 MHz frequency and room temperature 28 degrees C. The present investigation is useful in tissue differentiation and tissue identification to enable the doctors to give proper treatment.
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Singh VR, Raad I. Fatal Staphylococcus saprophyticus native valve endocarditis in an intravenous drug addict. J Infect Dis 1990; 162:783-4. [PMID: 2388008 DOI: 10.1093/infdis/162.3.783] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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Singh VR, Trewartha G, Roberts SP, England M, Stokes KA. Shoulder Injuries in English Community Rugby Union. Int J Sports Med 2016; 37:659-64. [PMID: 27176887 DOI: 10.1055/s-0042-104414] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The aim of this study was to describe the incidence, severity and type of shoulder injuries resulting from match play in adult community rugby union between 2009-2013. A total of 254 time-loss shoulder injuries were reported, an overall incidence of 2.2 per 1 000 h (95% CI: 1.9 to 2.4), and a mean injury severity of 9.5 weeks missed (95% CI: 8.2 to 10.8). The semi-professional group had an incidence of 2.8 injuries per 1 000 h (95% CI: 2.2 to 3.5), which was higher than the recreational group at 1.8 injuries per 1 000 h (95% CI: 1.4 to 2.2, p=0.004). The incidence of acromioclavicular joint injury for semi-professional players was 1.2 per 1 000 h (95% CI: 0.8 to 1.6); which was significantly higher than the incidence of this injury type in recreational players (0.5 per 1 000 h 95% CI: 0.3 to 0.7, p=0.002). Overall, back row players sustained the highest incidence of all shoulder injuries for a given playing position, 2.9 injuries per 1 000 h (95% CI: 2.2 to 3.6). The tackle was the main event associated with injury. Injury prevention programs and coaching strategies that consider tackle technique and physical conditioning of the shoulder region are therefore considered important.
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Agarwal R, Singh VR. Ultrasonic parameters and relationship between compressive strength, microstructure of gall bladder stones. EUROPEAN JOURNAL OF ULTRASOUND : OFFICIAL JOURNAL OF THE EUROPEAN FEDERATION OF SOCIETIES FOR ULTRASOUND IN MEDICINE AND BIOLOGY 2000; 11:143-6. [PMID: 10781663 DOI: 10.1016/s0929-8266(99)00078-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Patients with symptomatic stones are at a great risk for complications and these complications are a major cause of morbidity. The gall bladder stones may have a complex structure and variable composition. In the present investigation stones have been grouped into three categories namely cholesterol, bilirubinate and mixed, and a correlation between the surface structure, ultrasonic parameters and compressive strength is estimated. A double-probe through-transmission technique was used for the ultrasonic parameters study, a universal testing instrument for hardness and a scanning electron microscope (SEM) for microstructure study. Gall bladder stones of mixed type with higher ultrasonic velocity, less attenuation and higher crushing strength were found to be more difficult to break in comparison to other types of stones. SEM of mixed type stones showed rough surface as compared to bilirubinate and cholesterol stones. The results obtained as well as the relationship might be useful in the design of a focussed ultrasonic 0lithotripter.
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Singh VR, Sakamoto Y, Kataoka T, Kobayashi M, Yamazaki Y, Fujimori A, Chang FH, Huang DJ, Lin HJ, Chen CT, Toyosaki H, Fukumura T, Kawasaki M. Bulk and surface magnetization of Co atoms in rutile Ti(1-x)Co(x)O(2-δ) thin films revealed by x-ray magnetic circular dichroism. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:176001. [PMID: 21483080 DOI: 10.1088/0953-8984/23/17/176001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We have studied magnetism in Ti(1-x)Co(x)O(2-δ) thin films with various x and δ by soft x-ray magnetic circular dichroism (XMCD) measurements at the Co L(2, 3) absorption edges. The estimated ferromagnetic moment by XMCD was 0.15-0.24 µ(B)/Co at the surface, while in the bulk it was 0.82-2.25 µ(B)/Co, which is in the same range as the saturation magnetization of 1.0-1.5 µ(B)/Co. These results suggest an intrinsic origin of the ferromagnetism. The smaller moment of the Co atom at the surface is an indication of a magnetically dead layer of a few nanometers thick at the surface of the thin films.
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Seth B, Sahoo KK, Aravind KR, Sahu BB, Singh VR, Patra N. Statistical optimization of bacoside A biosynthesis in plant cell suspension cultures using response surface methodology. 3 Biotech 2020; 10:264. [PMID: 32509497 DOI: 10.1007/s13205-020-02258-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 05/13/2020] [Indexed: 01/03/2023] Open
Abstract
The in vitro cultures of Bacopa monnieri show poor production of the anti-Alzheimer's drug, bacoside A. Therefore, suitable bioprocess optimization strategy was developed for callus induction from leaf explants (30 days), followed by callus proliferation (15 days). Central Composite Design was implemented to analyze the effect of pH, photoperiod, naphthalene acetic acid (NAA), and benzylaminopurine (BAP) concentration for maximum biosynthesis of bacoside A using leaf explants as well as callus explants as the inoculum. Using the CCD responses, it was predicted that the best biomass concentration of 4.56 ± 0.53 g/l DW and bacoside A production of 14.04 ± 1.31 mg/g DW can be obtained using 5.4 pH, 18 h/6 h L/D photoperiod regime, and 1.2 mg/l BAP in combination with 0.2 mg/l NAA. The kinetic parameter values for maximum specific growth rate (0.16/day), saturation constant (7.35 g/l), inhibition constant (120 g/l), biomass yield (0.011 g/g), maintenance coefficient (0.02 g/g/day), and growth-associated (0.627 mg/g) and non-growth-associated (1.096 mg/g/day) bacoside A formation constants were determined experimentally in batch cultures using optimized conditions.
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Abstract
The piezoelectric effect is investigated for the first time in renal calculi in vitro. The kidney stones are shaped from solid samples as well as from stones crushed into powder and pressed into tablets. Presence of alpha quartz in the renal calculi is investigated by an X-ray technique and the presence of this constituent also helps to explain the piezoelectric effect in the renal calculi. The dielectric and piezoelectric parameters are studied in detail.
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Salunke S, Singh VR, Mahajan AV, Dasgupta I. Electronic structure of Na(2)CuP(2)O(7): a nearly 2D Heisenberg antiferromagnetic system. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:025603. [PMID: 21813988 DOI: 10.1088/0953-8984/21/2/025603] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We have employed first principles calculations to study the electronic structure and the implications for the magnetic properties of Na(2)CuP(2)O(7). Using the self-consistent tight-binding linearized muffin-tin orbital method and the Nth-order muffin-tin orbital downfolding method, we have calculated the various intrachain and interchain hopping parameters between the magnetic Cu(2+) ions. Our calculations for Na(2)CuP(2)O(7) reveal dominant intrachain hopping, but in contrast to the typical quantum spin chains the interchain hoppings are not negligible. The Wannier function plot of the Cu d(x(2)-y(2)) orbitals shows that the exchange interactions are primarily mediated by the oxygens and the distance between the oxygens in Na(2)CuP(2)O(7) is favorable for both intrachain and interchain interactions, suggesting the inapplicability of the one-dimensional Heisenberg model for this system, in agreement with recent experimental results.
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Zhang L, Gardner HJ, Chen XG, Singh VR, Hong X. Strain induced modulation of the correlated transport in epitaxial Sm0.5Nd0.5NiO3 thin films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:132201. [PMID: 25779981 DOI: 10.1088/0953-8984/27/13/132201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report a study of the effect of epitaxial strain on the correlated transport properties of 2-40 nm Sm0.5Nd0.5NiO3 (SNNO) films grown on different substrates. The metal-insulator transition (MIT) temperature T(MI) of the SNNO films increases with increasing tensile strain. While films on (0 0 1) LaAlO3 and (1 1 0) NdGaO3 substrates exhibit a sharp MIT and thermal hysteresis in the cooling-heating cycle, signaling a first-order transition, films on (0 0 1) SrTiO3 show a broad, second-order MIT. Hall effect measurements reveal hole-type charge carriers and thermally activated temperature dependence of the carrier density below T(MI). The corresponding activation energy is ∼80 meV for films on LaAlO3 and NdGaO3, and is suppressed to 25 meV for films on SrTiO3. The carrier mobility in the metallic state and variable range hopping (VRH) transport at a low temperature point significantly enhanced electron localization in SNNO on STO, which we believe is not simply driven by extrinsic effects such as oxygen vacancies, but rather is an intrinsic characteristic for films subject to tensile strain due to the elongated Ni-O bond and hence enhanced dynamic Jahn-Teller distortion. In ultrathin films above the electrical dead layer thickness (2-3 nm), we observe a more than 100 K increase of T(MI) for films on LaAlO3, which has been correlated with a crossover from 3D to 2D transport as revealed from VRH. We attribute the distinct transport characteristics to strain induced modulation of various energy scales associated with the Ni-O-Ni bond angle and Ni-O bond length, which collectively determine the delocalization bandwidth of the system.
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Yamazaki Y, Kataoka T, Singh VR, Fujimori A, Chang FH, Huang DJ, Lin HJ, Chen CT, Ishikawa K, Zhang K, Kuroda S. Effect of co-doping of donor and acceptor impurities in the ferromagnetic semiconductor Zn(1-x)Cr(x)Te studied by soft x-ray magnetic circular dichroism. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:176002. [PMID: 21483085 DOI: 10.1088/0953-8984/23/17/176002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We have performed x-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD) studies of the diluted ferromagnetic semiconductor Zn(1-x)Cr(x)Te doped with iodine (I) or nitrogen (N), corresponding to electron or hole doping, respectively. From the shape of the Cr 2p absorption peak in the XAS spectra, it was concluded that the Cr ions in the undoped, I-doped and lightly N-doped samples are divalent (Cr(2+)), while Cr(2+) and trivalent (Cr(3+)) coexist in the heavily N-doped sample. This result indicates that the doped nitrogen atoms act as acceptors but that doped holes are located on the Cr ions. In the magnetic field dependence of the XMCD signal at the Cr 2p absorption edge, ferromagnetic behaviors were observed in the undoped, I-doped, and lightly N-doped samples, while ferromagnetism was considerably suppressed in the heavily N-doped sample, which is consistent with the results of magnetization measurements.
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Singh VR, Singh K. Wireless Sensor Networks for biomedical applications in cancer hyperthermia. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2009; 2008:5160-3. [PMID: 19163879 DOI: 10.1109/iembs.2008.4650376] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In case of deep seated brain tumors or cancerous cells, focused ultrasound is found to be an effective treatment tool. Thermal profile under hyperthermia is studied here for a temperature rise of 4 to 5 degree centigrade (up to 42.5 degree), in case of therapeutic treatment of the tumors. An in vitro tumor is studied with temperature sensors to understand the thermal elevation in different layers and different directions of the tumor. A Wireless Sensor Network (WSN ) is developed to transmit the tumor thermal information to an expert clinician to monitor the health condition and for therapeutic control of ultrasound dosage level, particularly in case of elderly patients living in remote areas.
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Bindal VN, Singh VR, Singh G. Acoustic power measurement of medical ultrasonic probes using a strain gauge technique. ULTRASONICS 1980; 18:28-32. [PMID: 7350722 DOI: 10.1016/0041-624x(80)90049-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
A new method using a semiconductor strain guage is described for the measurement of the acoustic power output of ultrasonic medical therapy and other probe heads. The acoustic power output of the probe heads is found to be linearly related to the calibrated electrical output of the strain gauge transducer system, as expected theoretically. The instrument developed is inexpensive, portable and easy to operate for the routine measurement of ultrasonic output of the equipment in hospitals.
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Singh HR, Singh VR. Advantage technology, equitable usage of available resources and infrastructure and effective practice management--key to quality healthcare delivery in India. Stud Health Technol Inform 2007; 127:31-42. [PMID: 17901597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The impact of technological advancement and the widespread availability of resources and their utilization, to meet the health care requirements of the community, an important fundamental need of the human being. After food and shelter is discussed. Some of the most sought criteria relating to the technology selection and the practice management are devised and proposed for their implementation to achieve quality health, particularly in the rural areas. An insight into the government policies, programs and as a result, the impact on the ultimate goal of achieving the desired health care, mainly during the last two decades is covered here. A model of health care for remote areas is proposed here to assist in the improvement of the conditions of better health care and better quality of life of the human being.
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Singh VR. A new semiconductor lithotripsy sensor. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2007; 2004:2458-61. [PMID: 17270770 DOI: 10.1109/iembs.2004.1403710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Calibration of lithotripters is important for proper therapeutic treatment of the patients suffering with the presence of the stones in the kidney. Hence, a new semiconductor lithotripsy sensor is developed here to study the optimum performance of the kidney stone disintegrators. The present lithotripsy sensor has four-arm Wheatstone bridge sensor chip having associated electronics of signal conditioning, and amplifier etc. on the chip itself, and is fabricated, by using conventional bipolar IC process, in combination with bulk micromachining process. The starting material used is 5 ohm-cm p-type (100) silicon. The chip size is 3 mm square and the size of anisotropically etched diaphragm is 1.0mmx1.5 mmx20 micron (thickness). The pressure sensitivity is found to be 10 V/mm Hg pressure, with nonlinearity of 0.20% full scale output and thermal stability less than +1.5% over a temperature range of -50 degrees C to 300 degrees C. The smart semiconductor lithotripsy sensor, due to better sensitivity and resolution, is found useful in monitoring of the acoustic intensity level and pressure amplitude (in MPa range) of the shock waves generated by the ESWL. The calibration of the lithotripters is discussed here in detail.
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Singh VR, Agarwal R. Detection of quartz in renal calculi to exhibit piezoelectricity. JOURNAL OF BIOMEDICAL ENGINEERING 1991; 13:360. [PMID: 1890833 DOI: 10.1016/0141-5425(91)90120-v] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Letter |
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Vaz A, Singh VR, Wisinger DB, Moffitt M. Diarrhoea, fever, shock and bullous skin lesions after ingestion of raw oysters. Postgrad Med J 1999; 75:565-7. [PMID: 10616698 PMCID: PMC1741354 DOI: 10.1136/pgmj.75.887.565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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case-report |
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Singh VR, Agarwal R. Mechanical and ultrasonic parameters of kidney stones. THE JOURNAL OF LITHOTRIPSY & STONE DISEASE 1990; 2:117-23. [PMID: 10148928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
The mechanical and ultrasonic parameters of kidney stones have been measured in vitro. The techniques used for these measurements are briefly described and the data are presented. It was found that the mechanical crushing strength correlates with the acoustic velocity in the calculi, which in turn is a function of the stones' chemical deposition. It was shown that the crushing strength increased exponentially with velocity in the range from approximately 22 kg/mm2 to approximately 100 kg/mm2. The corresponding ultrasonic velocity in the stones varied between approximately 2,200 m/sec to about 3,000 m/sec. It is suggested that these data could be used to determine the desirable characteristics of a piezoelectric lithotripter.
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