17 results on '"Panday V"'
Search Results
2. Interaction between length and curvature in haptic shape perception
- Author
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Panday, V., Bergmann Tiest, Wouter, Movement Behavior, and Research Institute MOVE
- Published
- 2014
3. Influence of local properties on the perception of global object orientation
- Author
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Panday, V., Bergmann Tiest, W.M., Kappers, A.M.L., Physics of Man, Sub Human Perception, Movement Behavior, Sensorimotor Control, Research Institute MOVE, Physics of Man, and Sub Human Perception
- Subjects
Property (programming) ,Computer science ,business.industry ,media_common.quotation_subject ,05 social sciences ,Geometry ,Curvature ,050105 experimental psychology ,Computer Science Applications ,Human-Computer Interaction ,Cross section (geometry) ,03 medical and health sciences ,0302 clinical medicine ,Orientation (geometry) ,Perception ,Psychophysics ,Object-orientation ,0501 psychology and cognitive sciences ,Computer vision ,Artificial intelligence ,Mathematics::Differential Geometry ,Haptic perception ,business ,030217 neurology & neurosurgery ,media_common - Abstract
In previous studies, the effect on perception of individual features such as curvature and edges have been studied with specifically designed stimuli. However, the effect of local properties on the perception of the global object has so far received little attention. In this study, cylinders with an elliptical cross section and rectangular blocks were used to investigate the effect and relative importance of curvature, change in curvature and edges, as local properties, on the ability of subjects to determine the orientation of the stimuli, which is a global property. We found that when curvature was present the threshold to determine the orientation was 43 percent lower than when curvature was absent. When, in addition, the change in curvature could be felt, the threshold was 37 percent lower than when only curvature could be felt. Finally, when edges were felt during exploration, the threshold increased by 46 percent compared to when the subjects were instructed to avoid the edges in the blocks. We conclude that the perception of curvature and change in curvature improve the performance of humans in perception of the whole shape, whereas edges, when not directly contributing to the task, disrupt performance. © 2012 IEEE.
- Published
- 2012
- Full Text
- View/download PDF
4. The Influence of Edges as Salient Features in Haptic Shape Perception of 3D Objects
- Author
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Panday, V., Bergmann Tiest, W.M., Kappers, A.M.L., Physics of Man, and Sub Human Perception
- Abstract
Salient features help identify objects. However, they can also influence subsequent comparison between objects. In this study, we investigate the influence of edges on perception of the shape of 3D objects. We tested two conditions in which subjects were asked to indicate the orientation of a block by exploring it either statically without touching the edges or freely. When edges were excluded, the threshold to determine the orientation of a block was an aspect ratio of 1.030. When the edges were explored, the threshold was 1.045. We conclude that edges disrupt the precision at which 3D objects can be perceived.
- Published
- 2011
5. Integration of length and curvature in haptic perception
- Author
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Panday, V., Bergmann Tiest, W.M., Kappers, A.M.L., Panday, V., Bergmann Tiest, W.M., and Kappers, A.M.L.
- Abstract
We investigated if and how length and curvature information are integrated when an object is explored in one hand. Subjects were asked to explore four types of objects between thumb and index finger. Objects differed in either length, curvature, both length and curvature correlated as in a circle, or anti-correlated. We found that when both length and curvature are present, performance is significantly better than when only one of the two cues is available. Therefore, we conclude that there is integration of length and curvature. Moreover, if the two cues are correlated in a circular cross-section instead of in an anti-correlated way, performance is better than predicted by a combination of two independent cues. We conclude that integration of curvature and length is highly efficient when the cues in the object are combined as in a circle, which is the most common combination of curvature and length in daily life.
- Published
- 2014
- Full Text
- View/download PDF
6. Influence of Local Properties on the Perception of Global Object Orientation
- Author
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Physics of Man, Sub Human Perception, Panday, V., Bergmann Tiest, W.M., Kappers, A.M.L., Physics of Man, Sub Human Perception, Panday, V., Bergmann Tiest, W.M., and Kappers, A.M.L.
- Published
- 2012
7. The Influence of Edges as Salient Features in Haptic Shape Perception of 3D Objects
- Author
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Physics of Man, Sub Human Perception, Panday, V., Bergmann Tiest, W.M., Kappers, A.M.L., Physics of Man, Sub Human Perception, Panday, V., Bergmann Tiest, W.M., and Kappers, A.M.L.
- Published
- 2011
8. Effect of Tetrahydropalmatine, an Alkaloid on Spore Germination of Some Fungi
- Author
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Maurya, S., primary, Srivastava, J. S., additional, Jha, R. N., additional, Panday, V. B., additional, and Singh, U. P., additional
- Published
- 2001
- Full Text
- View/download PDF
9. Cremophor EL causes (pseudo-) non-linear pharmacokinetics of paclitaxel in patients
- Author
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Tellingen, O van, primary, Huizing, M T, additional, Panday, V R Nannan, additional, Schellens, J H M, additional, Nooijen, W J, additional, and Beijnen, J H, additional
- Published
- 1999
- Full Text
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10. Sampling and sample preparation methods for the analysis of trace elements in biological material
- Author
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Sansoni, B., Iyengar, V., and Panday, V. K.
- Abstract
In general, trace element analysis of biological material includes the following steps: Formulation of the question to be answered by the analytical data, sampling, sample preparation, ashing, dissolution, preconcentration, separation, preparation of the measurement sample, physical measurement (integral, spectral, calibration), data processing, data evaluation and answering the question. Both sampling and the sample preparation are crucial stages for any trace analysis. Knowledge of numerous factors and strict adherance to all the requirements is unavoidable, if results are to be reliable. Sampling of biological material involves some fundamental aspects such as representative mean composition, representative variance, accuracy and efficiency of sampling. The general sampling methods used may be random, systematic or of differentiated types. Various parameters such as size of the totality of material, number and size of the particles, distribution of trace elements between different types of particles influence the optimal size of the sample. There are some basic hazards in trace element analysis, which arise from contamination of the sample by the elements, lass of trace elements and change in mean composition with respect to the elements to be analysed. Contamination of the sample may occur fromthe environment, the sampling operation itself and the operating personnel. Trace elements may be lost by volatilization during drying and ashing, adsorption on container walls and handling tools, overlooked differences in the chemical state of the element and also bysputtering and spraying in case of liquids. The changes in the mean trace element composition of the sample may result from the physical or chemical changes and by redistribution of the elements. The main sampling operations for solid tissues include the selection of an optimal sampling method, the sampling site and the preparation of the sampling equipment. Liquid samples require additional treatment such as the use of a stabilizer and phase separation. lt is also necessary to obtain timed collection for samples such as urine and feces. Special restrictions have to be observed for both liquid and solid samples due to medical reasons, especially for in-vivo samples. Same sort of a preliminary preservation of both the solid and liquid samples is necessary du ring transport to the laboratory.Sample preparation of biological material is necessary in order to prepare the samples for obtaining the analytical signal. A few requirements such as a weil defined analytical programme, prior knowledge of the approximate elemental composition of the sample matrix and a reasonably clean bench to suit the low concentration level analytical work and adequate precautions against the basic hazards mentioned above are some of the basic necessities. [...]
- Published
- 1978
11. Platform for the interdisciplinary study of cardiovascular, metabolic and neurovascular diseases (PICMAN) protocol.
- Author
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Dalakoti M, Leow MKS, Khoo CM, Yang H, Ling LH, Muthiah M, Tan E, Lee J, Dan YY, Chew N, Seow WQ, Soong PL, Gan L, Gurung R, Ackers-Johnson M, Hou HW, Sachaphibulkij K, MacAry P, Low G, Ang C, Yeo TJ, Djohan AH, Li T, Yeung W, Soh R, Sia CH, Panday V, Loong SSE, Tan BYQ, Yeo LLL, Teo L, Chow P, and Foo R
- Subjects
- Humans, Male, Female, Cohort Studies, Prospective Studies, Risk Factors, Cardiovascular Diseases, Non-alcoholic Fatty Liver Disease, Cardiovascular System, Atherosclerosis
- Abstract
Through extensive multisystem phenotyping, the central aim of Project PICMAN is to correlate metabolic flexibility to measures of cardiometabolic health, including myocardial diastolic dysfunction, coronary and cerebral atherosclerosis, body fat distribution and severity of non-alcoholic fatty liver disease. This cohort will form the basis of larger interventional trials targeting metabolic inflexibility in the prevention of cardiovascular disease. Participants aged 21-72 years with no prior manifest atherosclerotic cardiovascular disease (ASCVD) are being recruited from a preventive cardiology clinic and an existing cohort of non-alcoholic fatty liver disease (NAFLD) in an academic medical centre. A total of 120 patients will be recruited in the pilot phase of this study and followed up for 5 years. Those with 10-year ASCVD risk ≥ 5% as per the QRISK3 calculator are eligible. Those with established diabetes mellitus are excluded. Participants recruited undergo a detailed assessment of health behaviours and physical measurements. Participants also undergo a series of multimodality clinical phenotyping comprising cardiac tests, vascular assessments, metabolic tests, liver and neurovascular testing. Blood samples are also being collected and banked for plasma biomarkers, 'multi-omics analyses' and for generation of induced pluripotent stem cells (iPSC). Extensive evidence points to metabolic dysregulation as an early precursor of cardiovascular disease, particularly in Asia. We hypothesise that quantifiable metabolic inflexibility may be representative of an individual in his/her silent, but high-risk progression towards insulin resistance, diabetes and cardiovascular disease. The platform for interdisciplinary cardiovascular-metabolic-neurovascular diseases (PICMAN) is a pilot, prospective, multi-ethnic cohort study., (© 2023. The Author(s).)
- Published
- 2023
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12. Long-term effects of bariatric surgery on cardiovascular risk factors in Singapore.
- Author
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Panday V, Shabbir A, Kuntjoro I, Khoo EYH, So JBY, and Poh KK
- Subjects
- Body Mass Index, Heart Disease Risk Factors, Humans, Prospective Studies, Retrospective Studies, Risk Factors, Singapore epidemiology, Treatment Outcome, Bariatric Surgery, Cardiovascular Diseases epidemiology, Diabetes Mellitus, Type 2 complications, Obesity, Morbid complications, Obesity, Morbid surgery
- Abstract
Introduction: Bariatric surgery is considered an effective treatment for weight loss and for improving the metabolic profile of patients with obesity. Obesity-related comorbidities such as hyperlipidaemia and type 2 diabetes mellitus (DM) are significant cardiovascular risk factors. Additionally, prospective clinical trials have shown that statins increase the risk of development of DM, and many patients with obesity are on statins. We retrospectively examined the effect of bariatric surgery on lipid profile, DM control and weight loss at the five-year follow-up., Methods: In total, 104 patients undergoing bariatric surgery from 2008 to 2012 were retrospectively studied. 36 patients were on preoperative statins. Their lipid profile, DM control and weight loss were examined at the one-year and five-year follow-ups., Results: Both high-density lipoprotein and triglyceride levels showed significant improvement at the one-year and five-year follow-ups (p = 0.01). Total cholesterol showed significant improvement at the one-year follow-up (-0.30 mmol/dL, p = 0.0338); however, better control was not sustained at the five-year follow-up (-0.15 mmol/dL, p = 0.133). Low-density lipoprotein did not show any considerable improvement at the one- and five-year follow-ups (-0.27 mmol/dL, p = 0.150 and -0.24 mmol/dL, p = 0.138, respectively). A statistically significant improvement in DM control was observed in these patients and in those on preoperative statins. Weight loss was sustained at one and five years., Conclusion: Bariatric surgery does not confer a uniform improvement in lipid profile in the long term. It does, however, induce efficient weight loss and improvement in diabetic profile, even in patients on preoperative statins., (Copyright: © Singapore Medical Association.)
- Published
- 2021
- Full Text
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13. Echocardiographic quantification of pulmonary artery systolic pressure in ventricular septal defect: Do calculations from Doppler interrogation across tricuspid regurgitation and ventricular septal defect correlate?
- Author
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Panday V, Tay EL, Chan PF, Yip JW, and Poh KK
- Subjects
- Adult, Echocardiography, Doppler methods, Female, Heart Septal Defects, Ventricular epidemiology, Humans, Male, Middle Aged, Pulmonary Artery physiology, Tricuspid Valve Insufficiency epidemiology, Blood Pressure physiology, Echocardiography, Doppler standards, Heart Septal Defects, Ventricular diagnostic imaging, Pulmonary Artery diagnostic imaging, Tricuspid Valve Insufficiency diagnostic imaging
- Published
- 2016
- Full Text
- View/download PDF
14. Comparative Evalution of G bone (Hydroxyapatite) and G-Graft (Hydroxyapatite with Collagen) as Bone Graft Material in Mandibular III Molar Extraction Socket.
- Author
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Panday V, Upadhyaya V, Berwal V, Jain K, Sah N, Sarathi P, and Swami PC
- Abstract
Background: Bone grafting is a dynamic phenomenon. It is a surgical procedure that replaces missing bone with material either from patient's own body, or, an artificial, synthetic or natural substitute. A successful bone graft when applied, heals, becomes incorporated, re-vascularises and eventually assumes the form desired., Aims and Objective: The main purpose of this present study was to radiologically assess and compare the regenerative potential of hydroxyapatite with Collagen (G-Graft) and hydroxyapatite (G-Bone) and to evaluate the clinical usefulness of these materials to enhance bone healing in third molar extraction sites through bone formation., Materials and Methods: The study was carried out in the Department of Oral & Maxillofacilal Surgery, patients were divided into three groups. The rationale for assigning the patients to the groups was strictly random: Group I - G-Graft (Hydroxyapatite with Collagen) was used as Bone graft material, Group II - Bone graft material used was G-Bone (Hydroxyapatite), Group III-control group (no grafts was used). Orthopentomogram(OPG) images were taken intra-operatively, just after extraction in the Group III (control), after extraction but before graft placement in Group I & II (study groups) and post-operatively at the end of first month and third month. Bone density of the post-extraction sockets was measured at four random areas through 'densitometric analysis' software in the OPG program (Kodak 8000C Digital Panoramic System, Eastman Kodak Company) and an average value was recorded at each review., Results: The percentage increase in bone density between 1(st) month & 3(rd) month was 7.55± 12.43 in Group I (G Graft), 4.41± 5.4859 in Group II (G Bone), while that Group III (control) was found to be -0.82 ± 3.96. The bone density increase was found to be statistically highly significant (p<0.01)) between all groups., Conclusion: The present study concluded that G-Graft has a definite regenerative potential and is better than G-bone and can be used in bony defects to enhance the bone healing without provoking any significant inflammatory process. The study also indicates that defects treated with G-Graft attain more density initially and that G-Graft enhances bone healing in early stage.
- Published
- 2015
- Full Text
- View/download PDF
15. Integration of length and curvature in haptic perception.
- Author
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Panday V, Tiest WM, and Kappers AM
- Subjects
- Cues, Female, Fingers physiology, Humans, Male, Psychomotor Performance physiology, Young Adult, Space Perception physiology, Touch physiology, Touch Perception physiology
- Abstract
We investigated if and how length and curvature information are integrated when an object is explored in one hand. Subjects were asked to explore four types of objects between thumb and index finger. Objects differed in either length, curvature, both length and curvature correlated as in a circle, or anti-correlated. We found that when both length and curvature are present, performance is significantly better than when only one of the two cues is available. Therefore, we conclude that there is integration of length and curvature. Moreover, if the two cues are correlated in a circular cross-section instead of in an anti-correlated way, performance is better than predicted by a combination of two independent cues. We conclude that integration of curvature and length is highly efficient when the cues in the object are combined as in a circle, which is the most common combination of curvature and length in daily life.
- Published
- 2014
- Full Text
- View/download PDF
16. PRK vs LASEK vs Epi-LASIK: a comparison of corneal haze, postoperative pain and visual recovery in moderate to high myopia.
- Author
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Reilly CD, Panday V, Lazos V, and Mittelstaedt BR
- Subjects
- Follow-Up Studies, Humans, Keratectomy, Subepithelial, Laser-Assisted adverse effects, Keratectomy, Subepithelial, Laser-Assisted methods, Photorefractive Keratectomy adverse effects, Photorefractive Keratectomy methods, Recovery of Function, Retrospective Studies, Severity of Illness Index, Treatment Outcome, Vision, Low epidemiology, Corneal Diseases epidemiology, Keratectomy, Subepithelial, Laser-Assisted statistics & numerical data, Myopia epidemiology, Myopia surgery, Pain, Postoperative epidemiology, Photorefractive Keratectomy statistics & numerical data
- Abstract
Introduction: The field of refractive surgery continues to evolve amid continued concerns as to which surgical technique minimizes the risk of inducing ectasia., Purpose: To compare clinical outcomes between PRK, LASEK and Epi-LASIK in moderately to highly myopic eyes (-4.00 D to -8.00 D)., Materials and Methods: A retrospective chart review of 100 PRK eyes, 100 LASEK eyes (with alcohol) and 97 Epi-LASIK eyes was performed. Post-operative pain, uncorrected visual acuity, and corneal haze data was recorded and analyzed at post-op days 1, 4 and 7 and at post-op months 1, 3, 6 and 12., Results: In all groups surgical corrections ranged from -4.00 D to -8.00 D. There was less pain associated with the epi-LASIK procedure especially early (post-op days 1 and 4). Visual recovery was superior within the PRK group during the first post-operative week but by post-op week 4 all three were equal. Haze scores were similar but a trend for less haze was demonstrated with epi-LASIK at 6 and 12 months., Conclusion: Epi-LASIK has a slight advantage over PRK and LASEK early on in the post-op course with regards to pain. Visual recovery is similar by 4 weeks and is better with PRK early. In addition, epi-LASIK trends toward less significant haze., (© Nepal Ophthalmic Society.)
- Published
- 2010
- Full Text
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17. A limited-sampling model for the pharmacokinetics of carboplatin administered in combination with paclitaxel.
- Author
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Nannan Panday VR, van Warmerdam LJ, Huizing MT, Ten Bokkel Huinink WW, Schellens JH, and Beijnen JH
- Subjects
- Aged, Antineoplastic Combined Chemotherapy Protocols pharmacokinetics, Area Under Curve, Female, Humans, Paclitaxel pharmacokinetics, Time Factors, Carboplatin pharmacokinetics, Carcinoma, Non-Small-Cell Lung drug therapy, Lung Neoplasms drug therapy, Models, Biological, Ovarian Neoplasms drug therapy
- Abstract
Purpose: Carboplatin doses are often determined by using modified Calvert formulas. It has been observed that the area under the concentration versus time curve (AUC) for free carboplatin is lower than expected when modified formulas are used for carboplatin/paclitaxel chemotherapy combination regimens. By using limited-sampling models, the carboplatin AUC actually reached can easily be verified, and the dose adjusted accordingly., Methods: In this report, we describe the development and validation of a limited-sampling model for carboplatin from 77 pharmacokinetic curves, when carboplatin is used in combination with paclitaxel., Results: The following single-point model was selected as optimal: AUC carboplatin (min mg(-1) ml(-1)) = 418. c(2.5 h)(mg/ml) + 0.43 (min mg(-1) ml(-1)), where c(2.5 h) is the concentration (mg/ml) of carboplatin 2.5 h after the start of a 30-min infusion. This model proved to be unbiased (mean prediction error = 3.4 +/- 1.6%) and precise (root mean square error = 10.1 +/- 1.5%)., Conclusions: The proposed model can be very useful for ongoing and future carboplatin/paclitaxel studies aimed to optimise and individualize treatment.
- Published
- 1999
- Full Text
- View/download PDF
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