26
|
Gupta S, Misra R, Ghosh UK, Gupta V, Srivastava D. Comparison of foetomaternal circulation in normal pregnancies and pregnancy induced hypertension using color Doppler studies. INDIAN JOURNAL OF PHYSIOLOGY AND PHARMACOLOGY 2014; 58:284-289. [PMID: 25906613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The aim of present study was to assess fetomaternal blood flows in normal and abnormal pregnancies using color Doppler indices. Subjects were divided into two groups as: Group A of 25 subjects of normal pregnancy as controls and group B of 25 subjects of pregnancy induced hypertension. All the subjects were lying in the age-group of 25-35 years and having 28 to 34 weeks of gestation; the patients were evaluated by detailed history and were subjected to complete general examination. Blood pressure was taken on two occasions at least 6 hours apart. Systemic examination and obstetrical examination was done in all subjects. All cases were subjected to pathological tests- Haemogram, Test for proteins in urine. Ultrasound assessment of fetal growth was done by measuring BPD (Biparietal diameter), HC (Head circumference), FL (Femur length) and AC (Abdominal circumference): Average gestational age and effective fetal weight was then calculated by ultrasound machine. Color Doppler was used to assess the various Doppler indices indices: Pulsatility index (PI), Resistive index (RI) and Systolic diastolic ratio (S/D ratio) in bilateral uterine, umbilical and middle cerebral arteries and compared to the standard normograms. Percentage of subjects having abnormal Doppler indices were calculated. Assessment of percentage of SGA (small for gestational age) fetuses was done in all the three groups. Decline in mean values of all Doppler indices was found with advancing gestational age in normal pregnancy suggesting decreased vascular resistance and increased blood flow in fetomaternal circulation. In pregnancy induced hypertensives, the mean values of Doppler indices showed a decline as in normal pregnancy but showed an increase (more than 2 S.D. of the mean) for that gestational age in comparison to the control group suggesting increased impedance to blood flow in uteroplacental and fetomaternal circulation. Umbilical artery Doppler indices were found to be the most sensitive indicator of uteroplacental and fetoplacental insufficiency in pregnancy induced hypertensives (P = 0.001). Thus we concluded that color Doppler can detect changes in fetomaternal circulation which correlate strongly with the fetal growth and therefore associated with pregnancy outcome.
Collapse
|
27
|
Nolkha N, Srivastava D, Wakhlu A, Dhakad U. Neuropathic arthropathy and syringomyelia complicating a case of ankylosing spondylitis with peripheral arthritis. CASE REPORTS 2014; 2014:bcr-2014-205604. [DOI: 10.1136/bcr-2014-205604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
|
28
|
Liu APY, Shing MMK, Yuen HL, Li CH, Ling SC, Luk CW, Ha SY, Li CK, Chan GCF, Tsui K, Gajjar A, Li C, Srivastava D, Broniscer A, Wetmore C, Kun LE, Merchant TE, Ellison DW, Orr B, Boop FA, Paul Klimo J, Ross JD, Robison LL, Armstrong GT, Walker D, Chu T, Shah A, Wilne S, Coleman M, Jaque FAM, Muthappan M, Law AJJ, Shing MMK, Chan GCF, Yuen HL, Lee RCH, Ling SC, Luk CW, Ha SY, Li CK, Mang OWS, Ngan RKC, Alston R, Estlin E, McCabe M, Birch J, Gattamaneni R, Kamaly-Asl I, Estlin E, Kamaly-Asl I, McCabe M, Birch J, Gattamaneni R, Alston R, Alston R, Estlin E, McCabe M, Gattamaneni R, Birch J, Kamaly-Asl I, Bendel A, Pond D, Woehrer A, Azizi AA, Heumesser R, Hackl M, Hainfellner JA, Dorfer C, Czech T, Chocholous M, Slavc I, Haberler C, Hami H, Ayoujil A, Habib F, Soulaymani A, Mokhtari A, Quyou A, Lim AHJ, Chan MY, Tan AM, Soh SY, Garba SM, Hami H, Zaki HM, Soulaymani A, Nouhou H, Quyou A, Owens-Pickle E, Smith A, Green AL, Schoettler M, Bandopadhayay P, Sauer N, Manley PE, Chi SN, Rodriguez-Galindo C, Kieran MW, Ribeiro K. EPIDEMIOLOGY. Neuro Oncol 2014. [DOI: 10.1093/neuonc/nou069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
29
|
Srivastava D, Chakrabarti O. Mahogunin-mediated α-tubulin ubiquitination via noncanonical K6 linkage regulates microtubule stability and mitotic spindle orientation. Cell Death Dis 2014; 5:e1064. [PMID: 24556679 PMCID: PMC3944237 DOI: 10.1038/cddis.2014.1] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 12/19/2013] [Accepted: 12/19/2013] [Indexed: 12/26/2022]
Abstract
Mahogunin ring finger-1 (MGRN1) is a cytosolic ubiquitin ligase whose disruption or interaction with some isoforms of cytosolically exposed prion protein leads to spongiform neurodegeneration and also lack of which results in reduced embryonic viability due to mispatterning of the left–right (LR) axis during development. Here we demonstrate an interaction between the cytoskeletal protein α-tubulin and MGRN1. In cultured cell systems, loss of the ubiquitin E3 ligase activity of MGRN1 results in spindle misorientation and decreased α-tubulin polymerization, an effect also seen in primary cells. α-Tubulin was post-translationally modified by MGRN1 via noncanonical K6-linked polyubiquitination. This was significant because expression of catalytically inactive MGRN1 and/or ubiquitin mutant capable of only monoubiquitination resulted in similar mitotic spindle misorientation. The modulatory effect of MGRN1 was specific for α-tubulin and similar changes could not be detected in β- or γ-tubulin. However, catalytic inactivation of MGRN1 did not abrogate monoubiquitination of α-tubulin, thus unraveling a unique dual mode of ubiquitination by an unknown E3 ligase and MGRN1. MGRN1-mediated α-tubulin modification, and hence its stability, may highlight a key event in the LR patterning during embryogenesis.
Collapse
|
30
|
Kulkarni R, Mani Krishna K, Neogy S, Srivastava D, Ramadasan E, Dey G, Saibaba N, Jha S, Shriwastaw R, Anantharaman S. Determination of correlation parameters for evaluation of mechanical properties by Small Punch Test and Automated Ball Indentation Test for Zr–2.5% Nb pressure tube material. NUCLEAR ENGINEERING AND DESIGN 2013. [DOI: 10.1016/j.nucengdes.2013.10.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
31
|
Srivastava D, Gupta A, Srivastava B. Distraction osteogenesis in cleft lip and palate. Int J Oral Maxillofac Surg 2013. [DOI: 10.1016/j.ijom.2013.07.586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
32
|
Gupta A, Srivastava D. Changing trends in maxillofacial trauma in Delhi and National Capital Region-multicentric retrospective study of 450 cases. Int J Oral Maxillofac Surg 2013. [DOI: 10.1016/j.ijom.2013.07.184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
33
|
Srivastava D. Efficacy of sacral neuromodulation in treating chronic pain related to painful bladder syndrome/interstitial cystitis in adults. J Anaesthesiol Clin Pharmacol 2012; 28:428-35. [PMID: 23225919 PMCID: PMC3511936 DOI: 10.4103/0970-9185.101890] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
OBJECTIVE The objective of this review is to evaluate the efficacy and safety of sacral neuromodulation in treating chronic pelvic pain related to Painful bladder syndrome/Interstitial-cystitis. DESIGN The databases searched were MEDLINE and EMBASE [1950- Nov 2011]. Additional searches were performed on the Cochrane Database of Systematic reviews (CDSR), Scopus, CINAHL, BIOSIS, The Cochrane controlled trials register, the science citation index, TRIP DATABASE. RESULTS Overall 70.8% or 170/244 patients were successful at the trial stage. The only randomized controlled trial reported a decrease in Visual analogue pain scores of 49% (7.9 to 4.0) for sacral nerve stimulation [SNS] and 29%(4.5 to 3.2) for pudendal nerve stimulation [PNS] at 6 months follow up. Nine observational studies reported a decrease in pain scores/decrease in pain medications at long term follow up following permanent sacral neuromodulation. One study showed an 80% improvement in Global response assessment score. CONCLUSION The results from the randomised controlled trial and case series/case reports demonstrate a reduction of pain symptoms of Painful bladder syndrome following sacral neuromodulation.
Collapse
|
34
|
Fox DA, Srivastava D, Poblenz A, He L. Lead-induced Alterations in Gene Expression and Activity of Retinal cGMP PDE Results in Calcium Overload and Rod-selective Apoptosis. Toxicol In Vitro 2012; 12:597-8. [PMID: 20654449 DOI: 10.1016/s0887-2333(98)00044-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
|
35
|
Agarwal A, Pandey R, Das V, Pandey A, Agarwal S, Jain V, Srivastava D. O017 IMPROVING EFFICACY OF MISOPROSTOL FOR INDUCTION OF SECOND TRIMESTER ABORTIONS. Int J Gynaecol Obstet 2012. [DOI: 10.1016/s0020-7292(12)60447-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
36
|
AlRais F, Feldstein VA, Srivastava D, Gosnell K, Moon-Grady AJ. Monochorionic twins discordant for congenital heart disease: a referral center's experience and possible pathophysiologic mechanisms. Prenat Diagn 2011; 31:978-84. [DOI: 10.1002/pd.2819] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Revised: 06/01/2011] [Accepted: 06/01/2011] [Indexed: 11/10/2022]
|
37
|
Brenner D, Robertson D, Carty R, Srivastava D, Garrison B. Combining Molecular Dynamics and Monte Carlo Simulations to Model Chemical Vapor Deposition: Application to Diamond. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-278-255] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractGas-surface reactions of the type that contribute to growth during the chemical vapor deposition (CVD) of diamond films are generally completed in picoseconds, well within timescales accessible by molecular dynamics (MD) simulations. For low-pressure deposition, however, the time between collisions for a surface site can be microseconds, which makes direct modeling of CVD crystal growth impossible using standard MD methods. To effectively bridge this discrepancy in timescales, the gas-surface reactions can be modeled using MD trajectories, and then this data can be used to define probabilities in a Monte Carlo algorithm where each step represents a gas-surface collision. We illustrate this approach using the reaction of atomic hydrogen with a diamond (111) surface as an example, where we use abstraction and sticking probabilities generated using classical trajectories in a simple Monte Carlo algorithm to determine the number of open sites as a function of temperature. We also include models for the thermal desorption of hydrogen that predict that growth temperatures are not restricted by the thermal loss of chemisorbed hydrogen.
Collapse
|
38
|
Ray D, Aswal VK, Srivastava D. Concentration effect on tuning of block copolymer-mediated synthesis of gold nanoparticles. JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 2010; 10:6356-6362. [PMID: 21137730 DOI: 10.1166/jnn.2010.2627] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Synthesis of gold nanoparticles has been examined using triblock copolymer Pluronic P85 (EO26PO39EO26) at different concentrations as a function of hydrogen tetrachloroaureate (III) hydrate (HAuCl4 x 3H2O) in aqueous solution. The concentration of P85 block copolymer was varied from 0.5 to 2 wt% at fixed temperature (30 degrees C) in presence of HAuCl4 x 3H2O in the range of 0.002 to 0.2 wt% for each P85 concentration. The surface plasmon resonance in the time-dependent UV-visible spectra reveals that increase in the block copolymer concentration increases the yield of the gold nanoparticles but decreases their stability. Both small-angle neutron scattering (SANS) and dynamic light scattering (DLS) show that the number density of block copolymer micelles increase almost linearly with the concentration, which is related to result in higher numbers of nucleation centers and therefore increase in the yield of gold nanoparticles. The fact that increase in the number density of nanoparticles also increases the chances of aggregation and this tends to decrease the stability at higher block copolymer concentration. Transmission electron microscopy (TEM) images confirm the larger sizes of the nanoparticles formed in these systems at higher concentrations.
Collapse
|
39
|
Srivastava D. Course on clinical management of chronic pain, Liverpool. Assoc Med J 2010. [DOI: 10.1136/bmj.c5171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
|
40
|
Mohamed SA, Nigam V, Jensen B, Sier H, Simpson P, Srivastava D, Sievers HH. Micrornas in bicuspid aortic valve: a comparison between stenosis and insufficiency aortic valve. Thorac Cardiovasc Surg 2010. [DOI: 10.1055/s-0029-1246793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
41
|
Armstrong GT, Pan Z, Ness K, Srivastava D, Robison LL. Temporal trends in cause-specific late mortality among five-year survivors of childhood cancer. J Clin Oncol 2009. [DOI: 10.1200/jco.2009.27.15_suppl.10004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
10004 Background: Five-year survival rates for childhood cancer have increased over the past 4 decades, increasing the number of long-term survivors. Among 5-yr survivors, the impact of changes in therapy on cause-specific late mortality has not been thoroughly assessed. Methods: Late mortality was evaluated over 3 eras (1974–81, 1982–90, 1991–2000) in 26,643 5-year survivors diagnosed <21 years of age from the SEER population-based registry. Cause-specific mortality was categorized as death from recurrence/progression of primary disease, external causes, and non-recurrence/non-external causes (Non-Recur/Ext) (i.e., deaths from health conditions including sequelae of cancer therapy). Results: All-cause and Recurrence mortality was significantly lower in more recent eras ( Table ). No significant improvement in late mortality attributable to Non-Recur/Ext causes was seen. Additionally, all-cause mortality was significantly lower in more recent eras for 5-year survivors of ALL, AML, Hodgkin, NHL, and CNS tumors, but not neuroblastoma and Ewing's Sarcoma where an increase in cumulative incidence of late mortality was seen in more recent eras. Significant improvement in late mortality from Recurrence by era was seen in most diagnostic groups. Conclusions: All-cause late mortality has improved with more recent eras, attributable to reduced rates of mortality from progression of primary disease (i.e., durable remission). Importantly, however, efforts to reduce the toxicity of more recent therapies have not produced detectable reduction in mortality attributable to other health conditions including sequelae of cancer therapy (non-Recur/Ext causes of death), which would include death from second malignancy, cardiac and pulmonary conditions. Worsening late mortality for 5-year survivors of neuroblastoma and Ewing's sarcoma may be due to improved use of salvage therapies that delay, but do not ultimately prevent death. [Table: see text] No significant financial relationships to disclose.
Collapse
|
42
|
Srivastava D, Srivastava B, Tripathi T. Surgical correction of mandibular malformations by distraction osteogenesis. Int J Oral Maxillofac Surg 2007. [DOI: 10.1016/j.ijom.2007.08.159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
43
|
SH C, Thulkar S, Srivastava D, Kumar L, Hariprasad R, Kumar S, Sharma M. Preoperative evaluation of epithelial ovarian cancer with multidetector computed tomography and its correlation with surgical outcome. J Clin Oncol 2007. [DOI: 10.1200/jco.2007.25.18_suppl.16051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
16051 Background: In the management of epithelial ovarian cancer (EOC), optimum debulking surgery (residual tumour of 1 cm or less) is the most important prognostic factor and is associated with higher survival We conducted a prospective study to evaluate the role of Multidetector (MD) CT scan to predict optimal debulking in advanced EOC. Methods: Between December, 2004 and October, 2006, 38 previously untreated patients (median age-50 years, range 26 to 70) were evaluated with contrast- enhanced MD CT scan of abdomen and pelvis. All CT scans were performed on four-slice MD CT scanner with thin slice image acquisition. Multiplanar coronal, sagital or oblique images were constructed and all images were reviewed by at least 2 radiologists. The extent of disease was determined and mapped for all areas of abdomen and pelvis. Patients underwent primary debulking surgery in which total abdominal hysterectomy, bilateral salphingo-oophorectomy, omentectomy and optimal cytoreduction was done. CT scan films were reviewed and compared with surgical findings. A CT scan scoring system was developed to predict the optimum debulking using 10 parameters: ascites, pelvic, peritoneal deposits, large bowel, small bowel, omentum, diaphragm, liver, lymphadenopathy and lesser sac. Each factor was assigned a score of 0 to 2. The statistical analysis was done using SPSS version 11 and EpiInfo 6 software. Results: The mean interval between CT scan and surgery was 11 days. 18 of 38 patients had a CT score = 7; all 18 had sub-optimal debulking. Of remaining 20 patients with CT score <7, 17(44.7%) had optimum and 3 had sub-optimal cytoreduction. The sensitivity and specificity was 85.7% (95% CI 62.6–96.2) and 100% (95% CI 77.1–100), respectively. It had positive predictive value of 100% and negative predictive value of 85% with accuracy of 92% in identification of patients who would not benefit from surgery. Presence of tumor at gall bladder fossa, porta hepatis, ligament teres, spleen , stomach, pancreas, lesser sack and pelvic side walls was associated with sub-optimal debulking. Conclusions: Pre-operative CT scan scoring helps to identify patients who are likely to have sub-optimal debulking and may be candidates for neoadjuvant chemotherapy No significant financial relationships to disclose.
Collapse
|
44
|
Talapatra S, Kim T, Wei BQ, Kar S, Vajtai R, Sastry GVS, Shima M, Srivastava D, Ajayan PM. Room Temperature Ferromagnetism in Graphitic Nanoclusters. ACTA ACUST UNITED AC 2006. [DOI: 10.1556/nano.1.2006.3.3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
45
|
|
46
|
Jayade CV, Ayoub AF, Khambay BS, Walker FS, Gopalakrishnan K, Malik NA, Srivastava D, Pradhan R. Skeletal stability after correction of maxillary hypoplasia by the Glasgow extra-oral distraction (GED) device. Br J Oral Maxillofac Surg 2006; 44:301-7. [PMID: 16162377 DOI: 10.1016/j.bjoms.2005.07.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2004] [Accepted: 07/05/2005] [Indexed: 11/19/2022]
Abstract
Maxillary distraction osteogenesis delivers excellent results, particularly in patients with clefts. In the past, devices such as the conventional facemask and the rigid external distraction device have been used to correct maxillary hypoplasia after a Le Fort I osteotomy. We describe a new device, the Glasgow extra-oral distraction device. The extent of skeletal and dental stability of corrections achieved in 10 patients with maxillary hypoplasia associated with clefts was satisfactory. This device costs little, can be produced in developing countries, and provides effective treatment for severe secondary deformity associated with clefts.
Collapse
|
47
|
W. Fox J, Srivastava D. Predicting local-regional richness relationships using island biogeography models. OIKOS 2006. [DOI: 10.1111/j.2006.0030-1299.14768.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
48
|
Talapatra S, Ganesan PG, Kim T, Vajtai R, Huang M, Shima M, Ramanath G, Srivastava D, Deevi SC, Ajayan PM. Irradiation-induced magnetism in carbon nanostructures. PHYSICAL REVIEW LETTERS 2005; 95:097201. [PMID: 16197243 DOI: 10.1103/physrevlett.95.097201] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2005] [Indexed: 05/04/2023]
Abstract
Nitrogen (15N) and carbon (12C) ion implantations with implant energy of 100 keV for different doses were performed on nanosized diamond (ND) particles. Magnetic measurements on the doped ND show ferromagnetic hysteresis behavior at room temperature. The saturation magnetization (M(s)) in the case of 15N implanted samples was found to be higher compared to the 12C implanted samples for dose sizes greater than 10(14) cm(-2). The role of structural modification or defects along with the carbon-nitrogen (C-N) bonding states for the observed enhanced ferromagnetic ordering in 15N doped samples is explained on the basis of x-ray photoelectron spectroscopy measurements.
Collapse
|
49
|
Kwon YW, Manthena C, Oh JJ, Srivastava D. Vibrational characteristics of carbon nanotubes as nanomechanical resonators. JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 2005; 5:703-12. [PMID: 16010925 DOI: 10.1166/jnn.2005.110] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Using eigenvalue analysis of mass and stiffness matrices directly computed from atomistic simulations, natural frequencies and mode shapes of various carbon nanotubes are studied. The stiffness matrix was developed from the Tersoff-Brenner potential for carbon-carbon interactions. The computed frequencies of the radial breathing modes of a variety of armchair (n, n) nanotubes agree well with results obtained by others using different techniques. In addition, the study reveals diverse mode shapes such as accordion-like axial modes, lateral bending modes, torsional modes, axial shear modes, and radial breathing modes for a variety of single-wall, multi-wall, and bamboo-type carbon nanotubes. The effects of different constraints on the carbon nanotube ends on the computed frequencies and mode shapes have been investigated for possible applications in vibration sensors or electromechanical resonators.
Collapse
|
50
|
Razdan A, Srivastava D. Indigenous dental implants in vascularised fibular grafts—Two cases. Int J Oral Maxillofac Surg 2005. [DOI: 10.1016/s0901-5027(05)81395-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|