230 results on '"J Das"'
Search Results
2. Quality and Safety Considerations in Stereotactic Radiosurgery and Stereotactic Body Radiation Therapy: An ASTRO Safety White Paper Update
- Author
-
Indra J. Das, Samantha L. Dawes, Michael M. Dominello, Brian Kavanagh, Curtis T. Miyamoto, Todd Pawlicki, Lakshmi Santanam, Yevgeniy Vinogradskiy, and Anamaria R. Yeung
- Subjects
Oncology ,Radiology, Nuclear Medicine and imaging - Published
- 2022
- Full Text
- View/download PDF
3. Dosimetric evaluation of high-Z inhomogeneity used for hip prosthesis: A multi-institutional collaborative study
- Author
-
Poonam, Yadav, Sha X, Chang, Chee-Wai, Cheng, Colleen M, DesRosiers, Raj K, Mitra, and Indra J, Das
- Subjects
Phantoms, Imaging ,Radiotherapy Planning, Computer-Assisted ,Biophysics ,Humans ,General Physics and Astronomy ,Radiotherapy Dosage ,Radiology, Nuclear Medicine and imaging ,Hip Prosthesis ,Radiotherapy, Intensity-Modulated ,General Medicine ,Radiometry ,Algorithms - Abstract
A multi-institutional investigation for dosimetric evaluation of high-Z hip prosthetic device in photon beam.A bilateral hip prosthetic case was chosen. An in-house phantom was built to replicate the human pelvis with two different prostheses. Dosimetric parameters: dose to the target and organs at risk (OARs) were compared for the clinical case generated by various treatment planning system (TPS) with varied algorithms. Single beam plans with different TPS for phantom using 6 MV and 15 MV photon beams with and without density correction were compared with measurement.Wide variations in target and OAR dosimetry were recorded for different TPS. For clinical case ideal PTV coverage was noted for plans generated with Corvus and Prowess TPS only. However, none of the TPS were able to meet plan objective for the bladder. Good correlation was noticed for the measured and the Pinnacle TPS for corrected dose calculation at the interfaces as well as the dose ratio in elsewhere. On comparing measured and calculated dose, the difference across the TPS varied from -20% to 60% for 6 MV and 3% to 50% for the 15 MV, respectively.Most TPS do not provide accurate dosimetry with high-Z prosthesis. It is important to check the TPS under extreme conditions of beams passing through the high-Z region. Metal artifact reduction algorithms may reduce the difference between the measured and calculated dose but still significant differences exist. Further studies are required to validate the calculational accuracy.
- Published
- 2022
- Full Text
- View/download PDF
4. A Poly-vinyl Alcohol (PVA)-based phantom and training tool for use in simulated Transrectal Ultrasound (TRUS) guided prostate needle biopsy procedures
- Author
-
Arun K. Thittai, Sathiyamoorthy Selladurai, Sitikantha Roy, Umesh Gautam, Yeswanth S Pydi, Naresh V. Datla, and Chandan J Das
- Subjects
Male ,Vinyl alcohol ,Phantoms, Imaging ,business.industry ,Biopsy, Needle ,Ultrasound ,Prostate ,Biomedical Engineering ,Biophysics ,Prostatic Neoplasms ,equipment and supplies ,Imaging phantom ,body regions ,chemistry.chemical_compound ,Prostate needle biopsy ,medicine.anatomical_structure ,chemistry ,Polyvinyl Alcohol ,Needle biopsy ,medicine ,Humans ,business ,Ultrasonography ,Biomedical engineering - Abstract
Trans-rectal ultrasound-guided needle biopsy is a well-established diagnosis technique for prostate cancer. To enhance the needle manoeuvring skills under ultrasound (US) guidance, it is preferable to train medical practitioners in needle biopsy on tissue-mimicking phantoms. This phantom should mimic the morphology as well as mechanical and acoustic properties of the human male pelvic region to provide a surgical experience and feedback. In this study, polyvinyl alcohol (PVA) was used and evaluated for prostate phantom development, that is stiffness tunable, US-compatible and durable phantom material. Three samples, each with 5%, 10%, and 15% concentration of PVA material, were prepared, and their mechanical and shrinkage characteristics were investigated. The anatomy of male pelvic region was used to develop an anatomically correct phantom. Later US-guided needle biopsy was performed on the phantom. The range of elastic moduli of the PVA samples was 2∼146 kPa. Their elastic moduli and volumes were found to remain statistically close from seventh to eighth freeze-thaw cycle (p>0.05). Initial US scans of the phantom resulted in satisfactory B-mode images, with a clear distinction between the prostate and its surrounding organs. This study demonstrated the applicability of PVA hydrogel as a phantom material for training in US-guided needle biopsy.
- Published
- 2021
- Full Text
- View/download PDF
5. Why is Tree Drought Mortality so Hard to Predict?
- Author
-
Nathan L. Stephenson, William R. L. Anderegg, Anna T. Trugman, Adrian J. Das, and Leander D. L. Anderegg
- Subjects
0106 biological sciences ,Tree physiology ,Ecology ,Climate ,Climate Change ,media_common.quotation_subject ,fungi ,Vulnerability ,food and beverages ,Climate change ,Stress physiology ,Forests ,Biology ,010603 evolutionary biology ,01 natural sciences ,Droughts ,Trees ,Surprise ,Tree (data structure) ,Ecosystem model ,Ecology, Evolution, Behavior and Systematics ,010606 plant biology & botany ,media_common - Abstract
Widespread tree mortality following droughts has emerged as an environmentally and economically devastating 'ecological surprise'. It is well established that tree physiology is important in understanding drought-driven mortality; however, the accuracy of predictions based on physiology alone has been limited. We propose that complicating factors at two levels stymie predictions of drought-driven mortality: (i) organismal-level physiological and site factors that obscure understanding of drought exposure and vulnerability and (ii) community-level ecological interactions, particularly with biotic agents whose effects on tree mortality may reverse expectations based on stress physiology. We conclude with a path forward that emphasizes the need for an integrative approach to stress physiology and biotic agent dynamics when assessing forest risk to drought-driven morality in a changing climate.
- Published
- 2021
- Full Text
- View/download PDF
6. Skin dose in radiation treatment of the left breast: Analysis in the context of prone versus supine treatment technique
- Author
-
Matthew C. Biagioli, Indra J. Das, Amitpal Singh Saini, Catherine S. Hwang, and William E. Lee
- Subjects
Supine position ,medicine.medical_treatment ,Beam spoiler ,Biophysics ,General Physics and Astronomy ,Breast Neoplasms ,Context (language use) ,Radiation ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Breast cancer ,Prone Position ,Supine Position ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,business.industry ,Radiotherapy Planning, Computer-Assisted ,Radiotherapy Dosage ,General Medicine ,Skin dose ,medicine.disease ,Radiation therapy ,030220 oncology & carcinogenesis ,Female ,Nuclear medicine ,business ,Bolus (radiation therapy) - Abstract
To determine how the skin dose varies in patients receiving radiation treatment for breast cancer in the prone and supine positions.Fifty patients were scanned in the prone and supine positions. A radiation treatment plan was created for the left breast using a 6-MV beam for a prescribed dose of 42.66 Gy in 16 fractions. The dose was calculated using 1- and 2.5-mm calculation grid sizes and the surface dose was compared in both techniques.The median gantry angles relative to the skin surface at the central axis were 8 and 52 degrees for treatment in the prone and supine positions, respectively. The mean dose difference between the prone and supine techniques was statistically significant from 3- to 5-mm depth for both grid sizes. For the 1-mm calculation grid size, the doses at 3-, 4-, and 5-mm depths in the prone and supine techniques were 87.80% and 89.10% (P 0.003), 91.92% and 94.50% (P 0.00), and 95.30% and 98.20% (P 0.00), respectively; for the 2.5-mm grid size, the respective doses were 87.10% and 88.59% (P 0.00), 91.60% and 94.63% (P 0.00), and 95.10% and 97.80% (P 0.00), respectively.This study demonstrates that the prone technique facilitates a relatively lower skin dose than the supine technique. This observation is probably due to the beam angle. The beam is more perpendicular to the skin surface in the prone technique, whereas it is more tangential in the supine technique, which may deliver a higher skin dose. Thus, the dose to the skin should be evaluated in the prone technique, and if desired, the skin dose could be carefully augmented via a bolus or beam spoiler.
- Published
- 2021
- Full Text
- View/download PDF
7. A novel approach for the energy recovery and position control of a hybrid hydraulic excavator
- Author
-
Santosh Kr. Mishra, Gyan Wrat, J. Das, Prabhat Ranjan, and Mohit Bhola
- Subjects
0209 industrial biotechnology ,Energy recovery ,Computer science ,Applied Mathematics ,020208 electrical & electronic engineering ,PID controller ,Context (language use) ,02 engineering and technology ,Energy consumption ,Linear actuator ,Prime mover ,Automotive engineering ,Computer Science Applications ,Accumulator (energy) ,Excavator ,020901 industrial engineering & automation ,Control and Systems Engineering ,0202 electrical engineering, electronic engineering, information engineering ,Electrical and Electronic Engineering ,Instrumentation - Abstract
The heavy earth moving machineries (HEMM) like hydraulic excavator play a major role in construction and mining industries. In this context, the energy saving strategies in hydraulic excavator needs to be addressed considering its vital importance. Since the hydraulic excavators are subjected to heavy loads, hence the opportunity to harness the potential gravitational energy (GPE) remains a key area which can be effectively explored in order to minimize the energy consumption in consideration with hydraulic excavator. In the projected system, the potential energy is stored as pressure energy in hydro-pneumatic accumulator. The upward movement of the boom is executed with the help of prime mover during the starting of the first duty cycle. In the latter duty cycles, the stored pressurized energy is utilized together with the prime mover energy capable to execute the upward movement of the boom. The position of the boom cylinder is controlled by using the conventional PID controller using proportional flow control valve (PFCV) and accumulator. The error between the actual position and demand position of the linear actuator is minimized along with attainment of superior controlled performance while utilizing Model Predictive Controller (MPC). The pressurized accumulator with PFCV has been utilized to cater the different position demands. This has been also justified both experimentally and analytically with the error in the permissible range of 2%. It has been observed that the proposed system is 10% more efficient in contrast to the conventional system.
- Published
- 2020
- Full Text
- View/download PDF
8. 815 Altered methylation of microRNA in the psoriatic epidermis highlights the Wnt pathway
- Author
-
D. Verma, N. Kasic, F. Jeppsson, C. Eding, M. Lysiak, S. Fekri, J. Das, and C. Enerbäck
- Subjects
Cell Biology ,Dermatology ,Molecular Biology ,Biochemistry - Published
- 2023
- Full Text
- View/download PDF
9. Dose prescription and reporting in stereotactic body radiotherapy: A multi-institutional study
- Author
-
Indra J. Das, Poonam Yadav, Aaron D. Andersen, Zhe Jay Chen, Long Huang, Mark P. Langer, Choonik Lee, Lin Li, Richard A. Popple, Roger K. Rice, Peter B. Schiff, Timothy C. Zhu, and Mohamed E. Abazeed
- Subjects
Oncology ,Radiology, Nuclear Medicine and imaging ,Hematology - Published
- 2023
- Full Text
- View/download PDF
10. Cr doped ZnO: Investigation of magnetic behaviour through SQUID and ESR studies
- Author
-
J. Das, B. K. Roul, V. V. Srinivasu, Diptiranjan Sahu, P.E. Amami, and Dilip Kumar Mishra
- Subjects
010302 applied physics ,Materials science ,Photoluminescence ,Dopant ,Analytical chemistry ,Sintering ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,law.invention ,symbols.namesake ,Ferromagnetism ,law ,0103 physical sciences ,symbols ,Diamagnetism ,Crystallite ,Electrical and Electronic Engineering ,0210 nano-technology ,Electron paramagnetic resonance ,Raman spectroscopy - Abstract
Polycrystalline Zn1-xCrxO (0.01 ≤ x ≤ 0.09) samples synthesised by solid state reaction technique were sintered at different temperatures following slow step sintering schedule, investigated for optical and magnetic properties using suitable characterisation techniques. Cr2O3 and CrO2 phases have been detected in the Raman spectra of Zn1-xCrxO samples with x ≥ 0.05. Photoluminescence study indicated improved optical property of the samples compared to undoped ZnO. While low percentage Cr doped samples show diamagnetic behaviour, different types of magnetic orderings are observed in the samples with higher percentage of dopants (x ≥ 0.05) for different sintering temperatures. The spin system and magnetic properties were analysed through Electron Spin Resonance study; g-value of 1.97 indicates Cr in 3+ valence state in ZnO. Presence of both Cr3+ and Cr4+ in ZnO understood to facilitate super exchange interactions to promote room temperature ferromagnetism. ESR study ensures improved magnetic homogeneity through slow step sintering process.
- Published
- 2019
- Full Text
- View/download PDF
11. Final Analysis of Consolidative Use of Radiotherapy to Block (CURB) Oligoprogression Trial - A Randomized Study of Stereotactic Body Radiotherapy for Oligoprogressive Metastatic Lung and Breast Cancers
- Author
-
C.J. Tsai, J.T. Yang, D.M. Guttmann, N. Shaverdian, J. Eng, R. Yeh, J. Girshman, J. Das, D. Gelblum, A.J. Xu, A. Namakydoust, A. Iqbal, J.M. Mann, I. Preeshagul, C. Hajj, E.F. Gillespie, S. Modi, C. Dang, P. Drullinsky, W. Zhi, Q. LaPlant, A. Rimner, J.Y. Shin, A.J. Wu, K. Ng, A. Gucalp, A.J. Khan, R. Sanford, J. Bromberg, A.D. Seidman, T.A. Traina, D.R. Gomez, J. Flynn, Z. Zhang, J.A. Patel, M. Berger, J.S. Reis-Filho, N.Y. Lee, N. Riaz, M.E. Robson, C.M. Rudin, and S.N. Powell
- Subjects
Cancer Research ,Radiation ,Oncology ,Radiology, Nuclear Medicine and imaging - Published
- 2022
- Full Text
- View/download PDF
12. 285 Differential DNA Methylation of microRNA-encoding Genes in Psoriatic Epidermis Highlights the Wnt Pathway
- Author
-
D. Verma, N. Kasic, F. Jeppson, C. Bivik-Eding, M. Lysiak, S. Zamani Fekri, J. Das, and C. Enerbäck
- Subjects
Cell Biology ,Dermatology ,Molecular Biology ,Biochemistry - Published
- 2022
- Full Text
- View/download PDF
13. Efficacy of Favipiravir in treatment of mild & moderate COVID-19 infection in Nepal: a multi-center, randomized, open-labelled, phase III clinical trial
- Author
-
P. Adhikari, J. Koirala, A. Shrestha, N. Bista, K. Maleku, J. Das, K. Bhandari, N. Adhikari, A. Rawal, K. Pandit, P. Gyawali, and S. Pant
- Subjects
Microbiology (medical) ,Infectious Diseases ,General Medicine - Published
- 2022
- Full Text
- View/download PDF
14. Technological visuo-cognitive training in Parkinson's disease: Protocol for a randomised cross-over trial
- Author
-
J. Das, R. Morris, G. Barry, R. Walker, and S. Stuart
- Subjects
Physical Therapy, Sports Therapy and Rehabilitation - Published
- 2022
- Full Text
- View/download PDF
15. Visual cueing for turning deficit in Parkinson's disease: Freezer vs non-freezer response
- Author
-
A. Butterfield, J. Das, R. Morris, G. Barry, R. Walker, M. Mancini, and S. Stuart
- Subjects
Physical Therapy, Sports Therapy and Rehabilitation - Published
- 2022
- Full Text
- View/download PDF
16. Consolidative Use of Radiotherapy to Block (CURB) Oligoprogression ― Interim Analysis of the First Randomized Study of Stereotactic Body Radiotherapy in Patients With Oligoprogressive Metastatic Cancers of the Lung and Breast
- Author
-
Chau T. Dang, J. Das, J. Bromberg, Quincey LaPlant, Atif J. Khan, Daniel R. Gomez, D.M. Guttmann, Annemarie F. Shepherd, Tiffany A. Traina, Steven Sugarman, Charles M. Rudin, Isabel Ruth Preeshagul, C.J. Tsai, J.M. Mann, Erin F. Gillespie, Shanu Modi, Carla Hajj, Elizabeth A. Comen, Rachel Ann Sanford, M.E. Robson, Wanqing Iris Zhi, Marsha Reyngold, Pamela Drullinsky, A. Iqbal, A.J. Xu, Ayca Gucalp, Jeffrey Girshman, Azadeh Namakydoust, Kenneth K.-S. Ng, Narek Shaverdian, R. Yeh, J.T. Yang, Zhigang Zhang, Simon N. Powell, Daphna Y. Gelblum, Juliana Eng, J.Y. Shin, Andreas Rimner, Andrew D. Seidman, and Abraham J. Wu
- Subjects
Oncology ,Cancer Research ,medicine.medical_specialty ,Radiation ,business.industry ,medicine.medical_treatment ,Cancer ,medicine.disease ,Interim analysis ,Primary tumor ,Radiation therapy ,Breast cancer ,Internal medicine ,Clinical endpoint ,medicine ,Radiology, Nuclear Medicine and imaging ,Lung cancer ,business ,Tumor marker - Abstract
Purpose/Objective(s) We hypothesize that there is an oligoprogressive state in metastatic cancer, in which disease control can be improved with local therapy to progressive lesions only. This study therefore evaluated the impact of stereotactic body radiotherapy (SBRT) to sites of oligoprogression in patients with metastatic non-small-cell lung cancer (NSCLC) and breast cancer with 1-5 progressive lesions. Materials/Methods We enrolled patients with metastatic NSCLC or breast cancer who received ≥ 1 line of systemic therapy and had oligoprogressive lesions amenable to SBRT. There was no upper limit of non-progressive lesions. Oligoprogression was defined as Response Evaluation or Positron Emission Tomography Response Criteria in Solid Tumors documented progression ≤ 5 individual lesions. Stratification factors included number of progressive sites (1 vs. 2-5), prior systemic therapy (immunotherapy vs. other), primary tumor (NSCLC vs. breast), and tumor marker status (driver mutation and hormone receptor status). Patients were randomized 1:1 between SBRT to all progressive sites plus palliative standard of care (SOC) vs. palliative SOC only. Systemic therapy was per physician's discretion. The primary endpoint was progression-free survival (PFS). We used a randomized phase II design with a one-sided alpha of 0.05 and a power of 0.80, yielding a target accrual of 160 patients. PFS was compared using one-sided stratified log-rank test. One interim analysis was planned. Results From January 2019 to May 2021, 102 patients were randomized - 58 NSCLC (30 in the SBRT arm) and 44 breast (22 in each arm). Median age was 67. Most patients (75%) had > 1 site of oligoprogression and 47% had > 5 total metastatic lesions. Fifty-five (54%) patients received immunotherapy. The majority of NSCLC (86%) did not harbor an actionable driver mutation and 32% of breast cancer were triple negative. Baseline factors were balanced between arms. At a median follow-up of 51 weeks, 71 patients progressed and 30 died. Median PFS was 22 weeks in the SBRT arm vs. 10 weeks in the palliative SOC arm (p=0.005). This was driven entirely by the PFS benefit from SBRT in the NSCLC patients (44 weeks with SBRT vs. 9 weeks with SOC; p=0.004). No difference in median PFS was seen in the breast cohort (18 weeks with SBRT vs. 17 weeks with SOC; p=0.5). In multivariable Cox model inclusive of stratification factors, age, sex, lines of systemic therapy, and change of systemic therapy, the PFS benefit of SBRT remained substantial in the NSCLC cohort (Hazard Ratio: 0.38; 95% CI: 0.18-77; p=0.007). Grade ≥2 adverse events occurred in 8 patients in the SBRT arm, including 1 grade 3 pneumonitis. Conclusion Inthis pre-planned interim analysis of the first and largest randomized trial of radiotherapy for oligoprogressive metastatic NSCLC and breast cancer, we demonstrated the benefit of SBRT to sites of oligoprogression on overall PFS, meeting the primary endpoint. The mechanism of the differential benefits between NSCLC and breast cohorts merits further evaluation.
- Published
- 2021
- Full Text
- View/download PDF
17. SMA – OUTCOME MEASURES AND REGISTRIES
- Author
-
J. Das, V. Hodgkinson, M. Rodrigues, J. Bullivant, H. Walker, V. Straub, C. Campbell, M. Guglieri, and A. Ambrosini
- Subjects
Neurology ,Pediatrics, Perinatology and Child Health ,Neurology (clinical) ,Genetics (clinical) - Published
- 2021
- Full Text
- View/download PDF
18. REGISTRIES AND CARE OF NMD
- Author
-
B. Watling, M. Fowler, L. Braithwaite, B. Palmafy, T. Chamora, J. Wilkins, C. Turner, P. Owens, Craig Campbell, J. Bullivant, S. Woods, C. Ogden, S. Cardiff, J. McKenna, D. Osredkar, J. Das, Michela Guglieri, A. Ambrosini, B. Tye, B. Leary, and Simon St
- Subjects
Neurology ,Pediatrics, Perinatology and Child Health ,Neurology (clinical) ,Genetics (clinical) - Published
- 2021
- Full Text
- View/download PDF
19. Landscape-scale variation in canopy water content of giant sequoias during drought
- Author
-
Roberta E. Martin, Nathan L. Stephenson, Tarin Paz-Kagan, Philip G. Brodrick, Gregory P. Asner, Adrian J. Das, Nicholas R. Vaughn, and Koren R. Nydick
- Subjects
0106 biological sciences ,Canopy ,Canyon ,geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,biology ,Sequoia ,Climate change ,Forestry ,Management, Monitoring, Policy and Law ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Water balance ,Agronomy ,Spatial ecology ,Environmental science ,Physical geography ,Sequoiadendron ,Water content ,0105 earth and related environmental sciences ,Nature and Landscape Conservation - Abstract
Recent drought (2012–2016) caused unprecedented foliage dieback in giant sequoias (Sequoiadendron giganteum), a species endemic to the western slope of the southern Sierra Nevada in central California. As part of an effort to understand and map sequoia response to droughts, we studied the patterns of remotely sensed canopy water content (CWC), both within and among sequoia groves in two successive years during the drought period (2015 and 2016). Our aims were: (1) to quantify giant sequoia responses to severe drought stress at a landscape scale using CWC as an indicator of crown foliage status, and (2) to estimate the effect of environmental correlates that mediate CWC change within and among giant sequoia groves. We utilized airborne high fidelity imaging spectroscopy (HiFIS) and light detection and ranging (LiDAR) data from the Carnegie Airborne Observatory to assess giant sequoia foliage status during 2015 and 2016 of the 2012–2016 droughts. A series of statistical models were generated to classify giant sequoias and to map their location in Sequoia and Kings Canyon National Parks (SEKI) and vicinity. We explored the environmental correlates and the spatial patterns of CWC change at the landscape scale. The mapped CWC was highly variable throughout the landscape during the two observation years, and proved to be most closely related to geological substrates, topography, and site-specific water balance. While there was an overall net gain in sequoia CWC between 2015 and 2016, certain locations (lower elevations, steeper slopes, areas more distant from surface water sources, and areas with greater climate water deficit) showed CWC losses. In addition, we found greater CWC loss in shorter sequoias and those growing in areas with lower sequoia stem densities. Our results suggest that CWC change indicates sequoia response to droughts across landscapes. Long-term monitoring of giant sequoia CWC will likely be useful for modeling and predicting their population-level response to future climate change.
- Published
- 2018
- Full Text
- View/download PDF
20. Skin recurrence in the radiation treatment of breast cancer
- Author
-
Indra J. Das, Juhi M. Purswani, L.M. Katz, Naamit K. Gerber, C.A. Perez, and A. McCarthy
- Subjects
Oncology ,medicine.medical_specialty ,business.industry ,Teaching Case ,MEDLINE ,medicine.disease ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Breast cancer ,030220 oncology & carcinogenesis ,Internal medicine ,Medicine ,Radiology, Nuclear Medicine and imaging ,business - Published
- 2018
- Full Text
- View/download PDF
21. Remote measurement of canopy water content in giant sequoias (Sequoiadendron giganteum) during drought
- Author
-
Roberta E. Martin, Emily J. Francis, Gregory P. Asner, Todd E. Dawson, Adrian J. Das, Nathan L. Stephenson, Nicolas R. Vaughn, Wendy L. Baxter, Koren R. Nydick, Tarin Paz-Kagan, and Anthony R. Ambrose
- Subjects
0106 biological sciences ,Canopy ,Tree canopy ,Drought stress ,010504 meteorology & atmospheric sciences ,biology ,National park ,Ecology ,Water stress ,Sequoia ,Forestry ,Management, Monitoring, Policy and Law ,biology.organism_classification ,01 natural sciences ,Environmental science ,Sequoiadendron ,Water content ,010606 plant biology & botany ,0105 earth and related environmental sciences ,Nature and Landscape Conservation - Abstract
California experienced severe drought from 2012 to 2016, and there were visible changes in the forest canopy throughout the State. In 2014, unprecedented foliage dieback was recorded in giant sequoia (Sequoiadendron giganteum) trees in Sequoia National Park, in the southern California Sierra Nevada mountains. Although visible changes in sequoia canopies can be recorded, biochemical and physiological responses to drought stress in giant sequoia canopies are not well understood. Ground-based measurements provide insight into the mechanisms of drought responses in trees, but are often limited to few individuals, especially in trees of tall stature such as giant sequoia. Recent studies demonstrate that remotely measured forest canopy water content (CWC) is a general indicator of canopy response to drought, but the underpinning leaf- to canopy-level causes of observed variation in CWC remain poorly understood. We combined field and airborne remote sensing measurements taken in 2015 and 2016 to assess the biophysical responses of giant sequoias to drought. In 49 study trees, CWC was related to leaf water potential, but not to the other foliar traits, suggesting that changes in CWC were made at whole-canopy rather than leaf scales. We found a non-random, spatially varying pattern in mapped CWC, with lower CWC values at lower elevation and along the outer edges of the groves. This pattern was also observed in empirical measurements of foliage dieback from the ground, and in mapped CWC across multiple sequoia groves in this region, supporting the hypothesis that drought stress is expressed in canopy-level changes in giant sequoias. The fact that we can clearly detect a relationship between CWC and foliage dieback, even without taking into account prior variability or new leaf growth, strongly suggests that remotely sensed CWC, and changes in CWC, are a useful measure of water stress in giant sequoia, and valuable for assessing and managing these iconic forests in drought.
- Published
- 2018
- Full Text
- View/download PDF
22. Leaf to landscape responses of giant sequoia to hotter drought: An introduction and synthesis for the special section
- Author
-
Todd E. Dawson, Roberta E. Martin, Wendy L. Baxter, Anthony R. Ambrose, Gregory P. Asner, Adrian J. Das, Nathan L. Stephenson, Tarin Paz-Kagan, and Koren R. Nydick
- Subjects
0106 biological sciences ,010504 meteorology & atmospheric sciences ,biology ,Resistance (ecology) ,Ecology ,Sequoia ,Climate change ,Forestry ,Management, Monitoring, Policy and Law ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Water balance ,Forest dieback ,Habitat ,Vulnerability assessment ,Spatial ecology ,Environmental science ,0105 earth and related environmental sciences ,Nature and Landscape Conservation - Abstract
Hotter droughts are becoming more common as climate change progresses, and they may already have caused instances of forest dieback on all forested continents. Learning from hotter droughts, including where on the landscape forests are more or less vulnerable to these events, is critical to help resource managers proactively prepare for the future. As part of our Leaf to Landscape Project, we measured the response of giant sequoia, the world’s largest tree species, to the extreme 2012–2016 hotter drought in California. The project integrated leaf-level physiology measurements, crown-level foliage dieback surveys, and remotely sensed canopy water content (CWC) to shed light on mechanisms and spatial patterns in drought response. Here we summarize initial findings, present a conceptual model of drought response, and discuss management implications; details are presented in the other four articles of the special section on Giant Sequoias and Drought. Giant sequoias exhibited both leaf- and canopy-level responses that were effective in protecting whole-tree hydraulic integrity for the vast majority of individual sequoias. Very few giant sequoias died during the drought compared to other mixed conifer tree species; however, the magnitude of sequoia drought response varied across the landscape. This variability was partially explained by local site characteristics, including variables related to site water balance. We found that low CWC is an indicator of recent foliage dieback, which occurs when stress levels are high enough that leaf-level adjustments alone are insufficient for giant sequoias to maintain hydraulic integrity. CWC or change in CWC may be useful indicators of drought stress that reveal patterns of vulnerability to future hotter droughts. Future work will measure recovery from the drought and strengthen our ability to interpret CWC maps. Our ultimate goal is to produce giant sequoia vulnerability maps to help target management actions, such as reducing other stressors, increasing resistance to hotter drought through prescribed fire or mechanical thinning, and planting sequoias in projected future suitable habitat, which may occur outside current grove distributions. We suggest that managers compare different types of vulnerability assessments and combine vulnerability maps with other sources of information to inform decisions.
- Published
- 2018
- Full Text
- View/download PDF
23. Magnetic Resonance Imaging-Transrectal Ultrasound Fusion Biopsy of the Prostate—An Update
- Author
-
Chandan J Das, Abdul Razik, and Sanjay Sharma
- Subjects
Image-Guided Biopsy ,Male ,medicine.medical_specialty ,030232 urology & nephrology ,Magnetic Resonance Imaging, Interventional ,Multimodal Imaging ,03 medical and health sciences ,0302 clinical medicine ,Text mining ,Prostate ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Ultrasonography, Interventional ,Fusion Biopsy ,Multimodal imaging ,medicine.diagnostic_test ,business.industry ,Ultrasound ,Prostatic Neoplasms ,Magnetic resonance imaging ,medicine.anatomical_structure ,030220 oncology & carcinogenesis ,Radiology ,Ultrasonography ,business - Published
- 2018
- Full Text
- View/download PDF
24. PO-1547 Dosimetric study of Adaptive radiotherapy (ART) for locally advanced head and neck cancer
- Author
-
J. Das, K.J. Deka, Barnali Goswami, G. Bora, Sanjay Goswami, and L. Das
- Subjects
medicine.medical_specialty ,Oncology ,business.industry ,Head and neck cancer ,Locally advanced ,Medicine ,Radiology, Nuclear Medicine and imaging ,Hematology ,Radiology ,Adaptive radiotherapy ,business ,medicine.disease - Published
- 2021
- Full Text
- View/download PDF
25. POS-226 CORTICOSTEROID USE, INFECTION, AND ADVERSE EVENTS AMONG IMMUNOGLOBULIN A NEPHROPATHY (IgAN) PATIENTS IN A US REAL-WORLD SETTING
- Author
-
C. ALDWORTH, R. Perkins, J. Kattlun, J. Doherty, A. George, J. Das, W. Wang, and R. Przybysz
- Subjects
Nephrology - Published
- 2022
- Full Text
- View/download PDF
26. Visual exploration while walking with and without visual cues in Parkinson's disease: The influence of freezing of gait
- Author
-
J. Armitage, J. Das, R. Morris, G. Barry, R. Walker, M. Mancini, and S. Stuart
- Subjects
Physical Therapy, Sports Therapy and Rehabilitation - Published
- 2022
- Full Text
- View/download PDF
27. POSA299 Impact of Implementing Difference Method for Sampling Ordered Parameter in Probabilistic Sensitivity Analysis (PSA) on Cost Effectiveness (CE) Model Outcome
- Author
-
J Das, A Mishra, and G Partha
- Subjects
Health Policy ,Public Health, Environmental and Occupational Health - Published
- 2022
- Full Text
- View/download PDF
28. Differential effect of body mass index (BMI) on outcomes of patients treated with docetaxel in prostate cancer - An exploratory analysis
- Author
-
Saurav Verma, Shalabh Arora, Ranjit Kumar Sahoo, Prabhjot Singh, Brusabhanu Nayak, KP Haresh, Chandan J Das, Shamim A Shamim, Seema Kaushal, and Atul Batra
- Subjects
Male ,Prostatic Neoplasms, Castration-Resistant ,Cancer Research ,Oncology ,nutritional and metabolic diseases ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,Humans ,Docetaxel ,Obesity ,Overweight ,RC254-282 ,Disease-Free Survival ,Body Mass Index - Abstract
Objective: : There are contradictory data on differential effect of docetaxel based on BMI in patients with breast and prostate cancer. We performed an exploratory analysis to determine if the benefit of docetaxel in patients with metastatic castration-resistant prostate cancer (mCRPC) is modified by BMI. Methods: : We performed a post hoc analysis of the data retrieved from the ENTHUSE M1C study. BMI (kg/m2) was categorized as: 18.5 to
- Published
- 2022
- Full Text
- View/download PDF
29. Analysis of an asymptotic preserving low mach number accurate IMEX-RK scheme for the wave equation system
- Author
-
Saurav Samantaray, K. R. Arun, and A. J. Das Gupta
- Subjects
Finite volume method ,Applied Mathematics ,Zero (complex analysis) ,Wave equation ,Stability (probability) ,Computational Mathematics ,symbols.namesake ,Mach number ,Scheme (mathematics) ,Convergence (routing) ,symbols ,Applied mathematics ,Limit (mathematics) ,Mathematics - Abstract
In this paper the analysis of an asymptotic preserving (AP) IMEX-RK finite volume scheme for the wave equation system in the zero Mach number limit is presented. An IMEX-RK methodology is employed to obtain a time semi-discrete scheme, and a space-time fully-discrete scheme is derived by using standard finite volume techniques. The existence of a unique numerical solution, its uniform stability with respect to the Mach number, and the accuracy at low Mach numbers are established for both time semi-discrete and space-time fully-discrete schemes. The AP property of the scheme is proved for a general class of IMEX schemes which need not be globally stiffly accurate. Extensive numerical case studies confirm uniform second order convergence of the scheme with respect to the Mach number and all the above-mentioned properties.
- Published
- 2021
- Full Text
- View/download PDF
30. Early detection and classification of internal leakage in boom actuator of mobile hydraulic machines using SVM
- Author
-
Gyan Wrat, J. Das, Joseph T. Jose, and Santosh Kr. Mishra
- Subjects
Support vector machine ,Downtime ,Artificial Intelligence ,Control and Systems Engineering ,Computer science ,Feature extraction ,Particle swarm optimization ,Electrical and Electronic Engineering ,Hydraulic machinery ,Actuator ,Fault (power engineering) ,Automotive engineering ,Leakage (electronics) - Abstract
Mobile hydraulic machines are used in various operations like construction, material handling and mining. High powers to weight ratio and manoeuvrability in rough terrains are striking features that help in edging out their electrical and mechanical counterparts. Internal leakage in hydraulic actuators is a faulty condition frequently observed in hydraulic machines. Internal leakage in the actuator affects the system’s dynamic performance and decreases its energy efficiency. Also, internal leakage is apparent only when the leakage is extreme and the actuator stops responding to command signals. Thus, detecting internal leakage in its early stages is a difficult task. Early detection and corrective action save energy, reduce component degradation, and reduce machine downtime. There are many existing techniques for internal leakage detection of hydraulic actuators, but they are intended for actuators working in a laboratory environment. The main focus of this paper is to present a practical method for early detection of internal leakage fault present in boom actuator of mobile hydraulic machines by analysing the machine work-cycle data with minimum hardware. The method trains and validates a Support Vector Machine (SVM) classifier using pressure and boom angle displacement signals. The time-series signals are processed using ’event-based’ feature extraction method. The binary version of Particle Swarm Optimisation is used for feature selection. The trained classifier can detect and classify internal leakage faults with more than 95% accuracy, which is sufficient for taking appropriate preventive maintenance steps on time.
- Published
- 2021
- Full Text
- View/download PDF
31. Spin canting and magnetism in nano-crystalline Zn1−xAlxO
- Author
-
V. V. Srinivasu, Dilip Kumar Mishra, and J. Das
- Subjects
Materials science ,Magnetism ,02 engineering and technology ,01 natural sciences ,law.invention ,Condensed Matter::Materials Science ,Magnetization ,symbols.namesake ,law ,0103 physical sciences ,Materials Chemistry ,Electron paramagnetic resonance ,Saturation (magnetic) ,010302 applied physics ,Spin polarization ,Condensed matter physics ,Mechanical Engineering ,Metals and Alloys ,021001 nanoscience & nanotechnology ,Ferromagnetism ,Mechanics of Materials ,symbols ,Condensed Matter::Strongly Correlated Electrons ,0210 nano-technology ,Raman spectroscopy ,Spin canting - Abstract
Al doped nanocrystalline ZnO (∼30 nm) with composition Zn1−xAlxO (0.005
- Published
- 2017
- Full Text
- View/download PDF
32. Design and performance assessment of cold compressor for a typical cold box of large tokamak machines
- Author
-
P. Patel, H.-S. Chang, J. Das, Srinivasa Muralidhara, and H. Vaghela
- Subjects
Overall pressure ratio ,Thermal efficiency ,Tokamak ,Materials science ,Liquid helium ,Nuclear engineering ,General Physics and Astronomy ,Superconducting magnet ,law.invention ,Impeller ,law ,Heat exchanger ,General Materials Science ,Gas compressor - Abstract
The Cold Compressor (CC) is used to lower the saturation temperature of liquid helium (LHe) under varying heat load conditions from the application side, i.e. superconducting magnets and cryopumps for large Tokamak machines. The CC is a key component of a typical cold box, attached to the LHe bath, which compresses and transfers the vapor generated during the heat exchange via heat exchangers as well as the flash generated downstream from the Joule-Thomson (JT) valve connected to the cryoplant. The emphasis of the present paper is a conceptual design and performance assessment of the CC. The CC is designed to pump 0.33 kg/sec of 4.2 K saturated helium vapor at a pressure ratio of 1.39; with an off-design range of 0.2–0.5 kg/sec. Operating speeds are between 10 and 25 krpm, with a speed of 17 krpm at the design point. Due to different heat loads from superconducting magnets and cryopumps, different process pressure and flow rates of the CC for large tokamak machines are expected. Hence, as an important component of the CC, the impeller design with blade profile generation has been carried for the higher thermodynamic efficiency of the CC. Characteristics curves of the CC have been obtained at different speed values. Analysis has been carried out using computational fluid dynamics (CFD) tool to analyze various situations during real operation.
- Published
- 2021
- Full Text
- View/download PDF
33. In Regard to Nichol et al
- Author
-
Amishi Bajaj and Indra J. Das
- Subjects
Cancer Research ,medicine.medical_specialty ,Radiation ,Oncology ,business.industry ,Family medicine ,MEDLINE ,Medicine ,Radiology, Nuclear Medicine and imaging ,business - Published
- 2021
- Full Text
- View/download PDF
34. PCN32 Comparative Efficacy of Combination of Dabrafenib and Trametinib Against Other Adjuvant Therapies for Melanoma
- Author
-
Barbara Ratto, J. Das, M. Kalra, and H. Banerjee
- Subjects
Trametinib ,Oncology ,medicine.medical_specialty ,business.industry ,Health Policy ,medicine.medical_treatment ,Melanoma ,Public Health, Environmental and Occupational Health ,Dabrafenib ,medicine.disease ,Internal medicine ,medicine ,business ,Adjuvant ,medicine.drug - Published
- 2021
- Full Text
- View/download PDF
35. A readily accessible porous organic polymer facilitates high-yielding Knoevenagel condensation at room temperature both in water and under solvent-free mechanochemical conditions
- Author
-
Goutam Nandi, Dejan-Krešimir Bučar, Dharittri Kakoti, Sanjeev P. Mahanta, Kashyap Kumar Sarmah, Ranjit Thakuria, Pranab J. Das, Nadeesh M. Adassooriya, and Parishmita Sarma
- Subjects
Knoevenagel condensation ,chemistry.chemical_classification ,Materials science ,010405 organic chemistry ,Process Chemistry and Technology ,General Chemistry ,Polymer ,010402 general chemistry ,Heterogeneous catalysis ,01 natural sciences ,Porous organic polymers ,Catalysis ,0104 chemical sciences ,Amorphous solid ,Amorphous materials ,Chemistry ,chemistry ,Chemical engineering ,Chemical stability ,Solubility ,Porosity ,QD1-999 ,Mechanochemistry - Abstract
A novel nitrogen-rich amorphous porous organic polymer has been synthesized using a microwave-assisted process. Its high chemical stability, reusability and poor solubility enable the use of the porous polymer as a metal-free heterogeneous catalyst for C C bond formation at ambient temperature under environmentally benign conditions.
- Published
- 2021
- Full Text
- View/download PDF
36. Evaluation of antioxidant, anti-inflammatory and anticancer activities of diosgenin enriched Paris polyphylla rhizome extract of Indian Himalayan landraces
- Author
-
Pallabi K. Hui, Vipin Rai, Tridip J. Das, Debmalya Das Gupta, Sumit Singh Verma, Shruti Mishra, Hui Tag, Nikee Awasthee, Anusmita Shekher, Subash C. Gupta, Dipayan Paul, and Sanjib K. Das
- Subjects
Male ,medicine.drug_class ,DPPH ,Survivin ,Anti-Inflammatory Agents ,India ,Apoptosis ,Diosgenin ,Antioxidants ,Anti-inflammatory ,HeLa ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Cell Line, Tumor ,Drug Discovery ,medicine ,Animals ,Edema ,Humans ,Rats, Wistar ,Medicinal plants ,Tumor Stem Cell Assay ,Cell Proliferation ,bcl-2-Associated X Protein ,030304 developmental biology ,Pharmacology ,0303 health sciences ,biology ,Traditional medicine ,Plant Extracts ,Paris polyphylla ,Dextrans ,biology.organism_classification ,Antineoplastic Agents, Phytogenic ,Rhizome ,Proto-Oncogene Proteins c-bcl-2 ,chemistry ,Phytochemical ,030220 oncology & carcinogenesis ,Melanthiaceae - Abstract
Traditional medicinal plants have gained attention as a potential therapeutic agent to combat cancer and inflammation. Diosgenin rich fresh extracts of Paris polyphylla rhizome from Indian Himalaya is traditionally used as wound healing, anti-bleeding, anti-inflammatory and anti-cancer agent by the folk healers.Present study was aimed to prepare two types of extracts from Paris polyphylla rhizome of Indian Himalayan landraces - 1. ethanolic extract of Paris polyphylla rhizome (EEPPR) and 2. Diosgenin enriched Paris polyphylla rhizome extract (DPPE), quantification of diosgenin content, and to evaluate their in vitro anti-oxidant, in vivo anti-inflammatory and in vitro cytotoxicity and anti-cancer activities of the DPPE.Diosgenin content of EEPPR was quantified through GC-MS while diosgenin content of DPPE was quantified through HPTLC, and the diosgenin yield from EEPPR and DPPE were compared. In vitro antioxidant activities of DPPE were performed using DPPH, NOD, RP and SOD assay while in vivo anti-inflammatory activity of DPPE were evaluated in dextran induced hind paw edema in rats. In vitro cytotoxicity and anti-cancer activities of DPPE were evaluated in human breast cancer cell lines (MCF-7, MDA-MB-231), cervical cancer cell lines (HeLa) and Hep-2 cell lines.EEPPR obtained through cold extraction method using 70% ethanol showed maximum diosgenin content of 17.90% quantified through GC-MS while similar compounds pennogenin (3.29%), 7β-Dehydrodiosgenin (1.90%), 7-Ketodiosgenin acetate (1.14%), and 7 β-hydroxydiosgenin (0.55%) were detected in low concentration, and thus confirmed diosgenin as major and lead phytochemical. However, DPPE obtained through both cold and repeated hot extraction with the same solvent (70% ethanol) showed diosgenin content of 60.29% which is significantly higher (p 0.001) than the diosgenin content in EEPPR. DPPE demonstrated significant in vitro antioxidant activities by dose-dependently quenched (p 0.001) SOD free radicals by 76.66%, followed by DPPH (71.43%), NOD (67.35%), and RP (63.74%) at a max concentration of 2 μg/μl of ascorbic acid and test drugs with remarkable ICDPPE obtained through both cold and repeated hot extraction using ethanol showed significantly higher content of diosgenin than the diosgenin content detected in EEPPR. However, diosgenin yield of both the extracts (EEPPRDPPE) clearly confirmed diosgenin as major and lead phytochemical of Paris polyphylla rhizome of Indian Himalayan landraces. Further, DPPE also demonstrated potent in vitro anti-oxidative and in vivo anti-inflammatory activities and showed in vitro cytotoxicity and significant anti-cancer (apoptosis) effects in MCF-7 breast cancer cells.
- Published
- 2021
- Full Text
- View/download PDF
37. State of dose prescription and compliance to international standard (ICRU-83) in intensity modulated radiation therapy among academic institutions
- Author
-
Eli Glatstein, Zhe Jay Chen, P. Sponseller, Jeremy D.P. Hoisak, Choonik Lee, Richard A. Popple, Mark Langer, L. Huang, R Rice, Andrea Dimofte, Timothy C. Zhu, A.D. Andersen, Indra J. Das, Matthew Pacella, and J. Smilowitz
- Subjects
Male ,medicine.medical_specialty ,medicine.medical_treatment ,Planning target volume ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,In patient ,Medical physics ,Medical prescription ,Retrospective Studies ,Analysis of Variance ,business.industry ,Radiotherapy Planning, Computer-Assisted ,Radiotherapy Dosage ,Retrospective cohort study ,Intensity-modulated radiation therapy ,Institutional review board ,Dose prescription ,Radiation therapy ,Treatment Outcome ,Oncology ,030220 oncology & carcinogenesis ,Practice Guidelines as Topic ,Guideline Adherence ,Radiotherapy, Intensity-Modulated ,Nuclear medicine ,business - Abstract
Purpose The purpose of this study was to evaluate dose prescription and recording compliance to international standard (International Commission on Radiation Units & Measurements [ICRU]-83) in patients treated with intensity modulated radiation therapy (IMRT) among academic institutions. Methods and materials Ten institutions participated in this study to collect IMRT data to evaluate compliance to ICRU-83. Under institutional review board clearance, data from 5094 patients—including treatment site, technique, planner, physician, prescribed dose, target volume, monitor units, planning system, and dose calculation algorithm—were collected anonymously. The dose-volume histogram of each patient, as well as dose points, doses delivered to 100% (D100), 98% (D98), 95% (D95), 50% (D50), and 2% (D2), of sites was collected and sent to a central location for analysis. Homogeneity index (HI) as a measure of the steepness of target and is a measure of the shape of the dose-volume histogram was calculated for every patient and analyzed. Results In general, ICRU recommendations for naming the target, reporting dose prescription, and achieving desired levels of dose to target were relatively poor. The nomenclature for the target in the dose prescription had large variations, having every permutation of name and number contrary to ICRU recommendations. There was statistically significant variability in D95, D50, and HI among institutions, tumor site, and technique with P values Conclusions Nearly 95% of patient treatments deviated from the ICRU-83 recommended D50 prescription dose delivery. This variability is significant (P
- Published
- 2017
- Full Text
- View/download PDF
38. The NSCL cyclotron gas stopper – Entering commissioning
- Author
-
J. J. Das, C. Magsig, Stefan Schwarz, Chandana Sumithrarachchi, Al Zeller, J. Ottarson, Shailendra Chouhan, Georg Bollen, David J. Morrissey, Michael A. Green, and Antonio Villari
- Subjects
Cryostat ,Nuclear and High Energy Physics ,Range (particle radiation) ,010308 nuclear & particles physics ,Cyclotron ,chemistry.chemical_element ,Field strength ,Superconducting magnet ,01 natural sciences ,law.invention ,Nuclear physics ,chemistry ,law ,Magnet ,0103 physical sciences ,Atomic physics ,010306 general physics ,Instrumentation ,Beam (structure) ,Helium - Abstract
Linear gas stopping cells have been used successfully at NSCL to slow down ions produced by projectile fragmentation from the 100 MeV/u to the keV energy range. These ‘stopped beams’ have first been used for low-energy high precision experiments and more recently for NSCLs re-accelerator ReA. A gas-filled reverse cyclotron is currently under construction by the NSCL to complement the existing stopping cells: Due to its extended stopping length, efficient stopping and fast extraction is expected even for light and medium-mass ions, which are difficult to thermalize in linear gas cells. The device is based on a 2.6 T maximum-field cyclotron-type magnet to confine the injected beam while it is slowed down in ≈100 mbar of LN2-temperature helium gas. Once thermalized, the beam will be transported to the center of the device by a traveling-wave RF-carpet system, extracted along the symmetry axis with an ion conveyor and miniature RF-carpets, and accelerated to a few tens of keV of energy for delivery to the users. The superconducting magnet has been constructed on a 60 kV platform and energized to its nominal field strength. The magnet’s two cryostats use 3 cryo-refrigerators each and liquid-nitrogen cooled thermal shields to cool the coil pair to superconductivity. This concept, chosen not to have to rely on external liquid helium, has been working well. Measurements of axial and radial field profiles confirm the field calculations. The individual RF-ion guiding components for low-energy ion transport through the device have been tested successfully. The beam stopping chamber with its 0.9 m-diameter RF carpet system and the ion extraction system are being prepared for installation inside the magnet for low-energy ion transport tests.
- Published
- 2016
- Full Text
- View/download PDF
39. Sn(II) inserted on hydroxyapatite encapsulated nickel ferrite (NiFe2O4@HAp-Sn2+): A novel nanocomposite for the effective photo-degradation of rhodamine B dye
- Author
-
J. Das, Krishna Ch. Das, Debasish Guha Thakurata, and Siddhartha Sankar Dhar
- Subjects
Materials science ,Nanocomposite ,Renewable Energy, Sustainability and the Environment ,020209 energy ,Strategy and Management ,05 social sciences ,Infrared spectroscopy ,Environmental pollution ,02 engineering and technology ,Industrial and Manufacturing Engineering ,chemistry.chemical_compound ,X-ray photoelectron spectroscopy ,chemistry ,Chemical engineering ,050501 criminology ,0202 electrical engineering, electronic engineering, information engineering ,Photocatalysis ,Rhodamine B ,Fourier transform infrared spectroscopy ,Selected area diffraction ,0505 law ,General Environmental Science - Abstract
The environmental remediation from polluting dyes has been one of the significant challenges that the researchers are facing across the globe. Scientist all over the world are not only focusing on environmentally benign method for synthesis of new materials but are also putting a lot of emphasis on developing newer efficient method of remediation of environmental pollution through green and clean technology. In this regard, it has been contemplated to design a novel material which can not only be prepared in an environment friendly manner but also can play an important role in making our environment cleaner through efficient removal of polluting dyes from the environment. Thus, the major focus of this paper has been given on the synthesis, characterization, and application of Sn(II) inserted on hydroxyapatite encapsulated nickel ferrite (NiFe2O4@HAp-Sn2+) novel nanocomposite. The composite was synthesized in three steps and well characterized by various characterization techniques such as powdered X-ray diffraction (PXRD), fourier transforms infrared spectroscopy(FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM) studies and energy dispersive X-ray spectroscopy (EDS) and ultraviolet diffused reflectance spectroscopy (UV-DRS) studies. The photocatalytic and adsorption efficiency of the composite was investigated in the degradation of Rhodamine B dye. The composite has been able to removed 62.5% of the dye by adsorption. However, the 84.4% degradation of the dye in presence of the photo-catalyst was achieved in 60 min without the assistance of any reductant or oxidant. Remarkably, in the presence of H2O2 the complete degradation (99.2%) of the dye was achieved just in 40 min only. This eco-friendly magnetically retrievable nanocomposite, proved to be a great material for removing the organic contaminant from the wastewater.
- Published
- 2021
- Full Text
- View/download PDF
40. Seed production patterns of surviving Sierra Nevada conifers show minimal change following drought
- Author
-
Micah Charles Wright, Phillip J. van Mantgem, Adrian J. Das, Nathan L. Stephenson, and Jon E. Keeley
- Subjects
0106 biological sciences ,Systematic difference ,biology ,Pollination ,food and beverages ,Forestry ,Priming (agriculture) ,Management, Monitoring, Policy and Law ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Basal area ,Ecological resilience ,Agronomy ,Forest ecology ,Forest recovery ,Calocedrus ,010606 plant biology & botany ,Nature and Landscape Conservation - Abstract
Reproduction is a key component of ecological resilience in forest ecosystems, so understanding how seed production is influenced by extreme drought is key to understanding forest recovery trajectories. If trees respond to mortality-inducing drought by preferentially allocating resources for reproduction, the recovery of the stand to pre-drought conditions may be enhanced accordingly. We used a 20-year annual seed capture data set to investigate whether seed production by three tree genera commonly found in the Sierra Nevada (Abies, Pinus, and Calocedrus) was correlated with variation in local weather, which included an extreme drought spanning multiple years. We tested whether average seed production differed during the drought years, and whether annual seed counts could be explained by three weather variables: spring temperature, annual precipitation, and summer climatic water deficit (CWD). We fit models testing for four separate effects: (1) a priming year model (weather 1 year prior to reproductive bud initiation), (2) a bud initiation model (weather in the year of reproductive bud initiation), (3) a pollination year model (weather in the year of pollination), and (4) maturation year model (weather in the year of seed maturation). For genera with two-year reproductive cycles, the pollination and maturation models were combined. We found support for the summer CWD Abies maturation year model, which suggested higher seed outputs immediately following dry summer conditions. The spring temperature pollination year model was selected for Pinus, which suggested that seed output is higher following warm spring weather during pollination. The annual precipitation priming year model was selected for Calocedrus, which showed a negative association between seed production and wetter conditions two years prior to seed production. More parent tree basal area resulted in higher seed output for all genera, though the confidence intervals overlapped 0 for Calocedrus. Permutation tests suggested there was no systematic difference in mean seed production during the drought after accounting for live tree basal area, regardless of genus. These results highlight the variability in response across genera, and suggest that the influence of seed production on forest recovery following drought-related mortality may depend on affected species and the timing of the mortality event within the masting cycle. A greater understanding of species-level masting to drought stress is needed to more precisely predict community-level recovery following drought.
- Published
- 2021
- Full Text
- View/download PDF
41. Segmentation of prostate zones using probabilistic atlas-based method with diffusion-weighted MR images
- Author
-
Virendra Kumar, Dharmesh Singh, Anup Singh, Chandan J Das, and Amit Mehndiratta
- Subjects
Male ,Jaccard index ,Partial volume ,Health Informatics ,Prostate cancer ,Prostate ,Image Processing, Computer-Assisted ,medicine ,Humans ,Segmentation ,Mathematics ,Active contour model ,business.industry ,Prostatic Neoplasms ,Pattern recognition ,medicine.disease ,Magnetic Resonance Imaging ,Computer Science Applications ,Diffusion Magnetic Resonance Imaging ,medicine.anatomical_structure ,Artificial intelligence ,business ,Opening ,Algorithms ,Software ,Diffusion MRI - Abstract
Accurate segmentation of prostate and its zones constitute an essential preprocessing step for computer-aided diagnosis and detection system for prostate cancer (PCa) using diffusion-weighted imaging (DWI). However, low signal-to-noise ratio and high variability of prostate anatomic structures are challenging for its segmentation using DWI. We propose a semi-automated framework that segments the prostate gland and its zones simultaneously using DWI.In this paper, the Chan-Vese active contour model along with morphological opening operation was used for segmentation of prostate gland. Then segmentation of prostate zones into peripheral zone (PZ) and transition zone (TZ) was carried out using in-house developed probabilistic atlas with partial volume (PV) correction algorithm. The study cohort included MRI dataset of 18 patients (n = 18) as our dataset and methodology were also independently evaluated using 15 MRI scans (n = 15) of QIN-PROSTATE-Repeatability dataset. The atlas for zones of prostate gland was constructed using dataset of twelve patients of our patient cohort. Three-fold cross-validation was performed with 10 repetitions, thus total 30 instances of training and testing were performed on our dataset followed by independent testing on the QIN-PROSTATE-Repeatability dataset. Dice similarity coefficient (DSC), Jaccard coefficient (JC), and accuracy were used for quantitative assessment of the segmentation results with respect to boundaries delineated manually by an expert radiologist. A paired t-test was performed to evaluate the improvement in zonal segmentation performance with the proposed PV correction algorithm.For our dataset, the proposed segmentation methodology produced improved segmentation with DSC of 90.76 ± 3.68%, JC of 83.00 ± 5.78%, and accuracy of 99.42 ± 0.36% for the prostate gland, DSC of 77.73 ± 2.76%, JC of 64.46 ± 3.43%, and accuracy of 82.47 ± 2.22% for the PZ, and DSC of 86.05 ± 1.50%, JC of 75.80 ± 2.10%, and accuracy of 91.67 ± 1.56% for the TZ. The segmentation performance for QIN-PROSTATE-Repeatability dataset was, DSC of 85.50 ± 4.43%, JC of 75.00 ± 6.34%, and accuracy of 81.52 ± 5.55% for prostate gland, DSC of 74.40 ± 1.79%, JC of 59.53 ± 8.70%, and accuracy of 80.91 ± 5.16% for PZ, and DSC of 85.80 ± 5.55%, JC of 74.87 ± 7.90%, and accuracy of 90.59 ± 3.74% for TZ. With the implementation of the PV correction algorithm, statistically significant (p0.05) improvements were observed in all the metrics (DSC, JC, and accuracy) for both prostate zones, PZ and TZ segmentation.The proposed segmentation methodology is stable, accurate, and easy to implement for segmentation of prostate gland and its zones (PZ and TZ). The atlas-based segmentation framework with PV correction algorithm can be incorporated into a computer-aided diagnostic system for PCa localization and treatment planning.
- Published
- 2020
- Full Text
- View/download PDF
42. Hemodialysis in Infants: Challenges and New Paradigms
- Author
-
Sanjiv Sharma, Chandan J Das, and Abdul Razik
- Subjects
medicine.medical_specialty ,business.industry ,medicine.medical_treatment ,MEDLINE ,Infant ,Retrospective cohort study ,Cohort Studies ,Renal Dialysis ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Hemodialysis ,Cardiology and Cardiovascular Medicine ,Intensive care medicine ,business ,Retrospective Studies ,Cohort study - Published
- 2020
- Full Text
- View/download PDF
43. Optimization of GATE and PHITS Monte Carlo code parameters for spot scanning proton beam based on simulation with FLUKA general-purpose code
- Author
-
Keita Kurosu, Indra J. Das, and Vadim P. Moskvin
- Subjects
Nuclear and High Energy Physics ,Instrumentation - Published
- 2016
- Full Text
- View/download PDF
44. Selective O-methylation of phenols and benzyl alcohols in simple pyridinium based ionic liquids
- Author
-
Pranab J. Das and Jupitara Das
- Subjects
Methylation ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Catalysis ,chemistry.chemical_compound ,Methylating Agent ,chemistry ,Yield (chemistry) ,Ionic liquid ,Materials Chemistry ,Phenol ,Organic chemistry ,Phenols ,Pyridinium ,Physical and Theoretical Chemistry ,Spectroscopy - Abstract
Synthesis of pyridinium based ionic liquids were reported and applied as catalyst for the selective O-methylation of phenols and benzyl alcohols. The reactions were carried out by using dimethylcarbonate (DMC) as the methylating agent. High selectivity, high yield and recyclability of the ionic liquids are important features of the reactions.
- Published
- 2015
- Full Text
- View/download PDF
45. Photoluminescence and Raman studies for the confirmation of oxygen vacancies to induce ferromagnetism in Fe doped Mn:ZnO compound
- Author
-
D. R. Sahu, B. K. Roul, Dilip Kumar Mishra, V. V. Srinivasu, and J. Das
- Subjects
Materials science ,Condensed matter physics ,Doping ,Analytical chemistry ,Magnetic semiconductor ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,law.invention ,Magnetization ,symbols.namesake ,Transition metal ,Ferromagnetism ,Impurity ,law ,symbols ,Electron paramagnetic resonance ,Raman spectroscopy - Abstract
With a motivation to compare the magnetic property, we synthesised undoped, transition metal (TM) Mn doped and ( Mn:Fe) co-doped ZnO ceramics in the compositions ZnO, Zn 0.98 Mn 0.02 O and Zn 0.96 (Mn 0.02 Fe 0.02 )O. Systematic investigations on the structural, microstructural, defect structure and magnetic properties of the samples were performed. Low temperature as well as room temperature ferromagnetism has been observed for all our samples, however, enhanced magnetisation at room temperature has been noticed when ZnO is co-doped with Fe along with Mn. Particularly the sample with the composition Zn 0.96 Mn 0.02 Fe 0.02 O showed a magnetisation value more than double of the sample with composition Zn 0.98 Mn 0.02 O, indicating long range strong interaction between the magnetic impurities leading to higher ferromagnetic ordering. Raman and PL studies reveal presence of higher defects in form of oxygen vacancy clusters created in the sample due to Fe co doping. PL study also reveals enhanced luminescence efficiency in the co doped sample. Temperature dependent magnetisation study of this sample shows the spin freezing temperature around 39 K indicating the presence of small impurity phase of Mn 2− x Zn x O 3 type. Electron Spin Resonance signal obtained supports ferromagnetic state in the co doped sample. Enhancement of magnetisation is attributed to interactions mediated by magnetic impurities through large number of oxygen vacancies created by Fe 3+ ions forming bound magnetic polarons (BMP) and facilitating long range ferromagnetic ordering in the co- doped system.
- Published
- 2015
- Full Text
- View/download PDF
46. Nox4-mediated ROS production is involved, but not essential for TGFβ-induced lens EMT leading to cataract
- Author
-
Tayler F.L. Wishart, Frank J. Lovicu, Karin Jandeleit-Dahm, and Shannon J. Das
- Subjects
Male ,0301 basic medicine ,Genotyping Techniques ,Smad2 Protein ,SMAD ,Mice ,0302 clinical medicine ,Transforming Growth Factor beta ,Fluorescent Antibody Technique, Indirect ,Cells, Cultured ,Mice, Knockout ,Mitogen-Activated Protein Kinase 1 ,chemistry.chemical_classification ,Mitogen-Activated Protein Kinase 3 ,NADPH oxidase ,biology ,Chemistry ,NOX4 ,Sensory Systems ,Cell biology ,medicine.anatomical_structure ,NADPH Oxidase 4 ,Lens (anatomy) ,cardiovascular system ,Electrophoresis, Polyacrylamide Gel ,Female ,Epithelial-Mesenchymal Transition ,Anterior subcapsular cataract ,Blotting, Western ,Mice, Transgenic ,Real-Time Polymerase Chain Reaction ,Cataract ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,Cataracts ,Downregulation and upregulation ,Lens, Crystalline ,medicine ,Animals ,Smad3 Protein ,Reactive oxygen species ,urogenital system ,Epithelial Cells ,medicine.disease ,Fibrosis ,Ophthalmology ,030104 developmental biology ,030221 ophthalmology & optometry ,biology.protein ,Reactive Oxygen Species - Abstract
The reactive oxygen species (ROS) producing enzyme, NADPH oxidase 4 (Nox4), is upregulated in response to TGFβ in lens epithelial cells in vitro, and its selective inhibition was shown to block aspects of TGFβ-induced epithelial-mesenchymal transition (EMT). In the present in situ study we validate the role(s) of Nox4 in TGFβ-induced lens EMT leading to anterior subcapsular cataract (ASC) formation. Mice overexpressing TGFβ in the lens, that develop ASC, were crossed to Nox4-deficient mice. When comparing mice overexpressing TGFβ in lens, to mice that were also deficient for Nox4, we see the delayed onset of cataract, along with a delay in EMT protein markers normally associated with TGFβ-induced fibrotic cataracts. In the absence of Nox4, we also see elevated levels of ERK1/2 activity that was shown to be required for TGFβ/Smad2/3-signaling. qRT-PCR revealed upregulation of Nox2 and its regulatory subunit in TGFβ-overexpressing lens epithelial cells devoid of Nox4. Taken together, these findings provide an improved platform to delineate putative Nox4 (and ROS) interactions with Smad2/3 and/or ERK1/2, in particular in the development of fibrotic diseases, such as specific forms of cataract.
- Published
- 2020
- Full Text
- View/download PDF
47. Critical insights into antibiotic resistance transferability in probiotic Lactobacillus
- Author
-
Aparna Shankar, Sabu Thomas, Devika J. Das, and John B. Johnson
- Subjects
0301 basic medicine ,medicine.drug_class ,Endocrinology, Diabetes and Metabolism ,Antibiotics ,030209 endocrinology & metabolism ,Drug resistance ,Gut flora ,law.invention ,03 medical and health sciences ,Probiotic ,0302 clinical medicine ,Antibiotic resistance ,law ,medicine ,Humans ,Bifidobacterium ,030109 nutrition & dietetics ,Nutrition and Dietetics ,biology ,business.industry ,Probiotics ,Drug Resistance, Microbial ,biology.organism_classification ,medicine.disease ,Biotechnology ,Lactobacillus ,Conjugation, Genetic ,Transformation, Bacterial ,Beneficial organism ,business ,Dysbiosis - Abstract
Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host, with respect to metabolism, immune function, and nutrition. Any perturbation of these beneficial microbes leads to gut dysbiosis, which triggers the development of various disorders in the gastrointestinal system. Probiotics play a key role in resolving the dysbiosis posed by external factors such as antibiotics, other substances, or interventions. Supplementing probiotics with antibiotics is favorable in reducing the harmful effects of antibiotics on gut flora. These microbes also possess specific intrinsic drug resistance mechanisms that aid their survival in the internal environment. According to US Food and Drug Administration reports, species belonging to Lactobacillus and Bifidobacterium genera are the most common probiotics consumed by humans through commercial products. However, various studies have reported the tendency of microbes to acquire specific drug resistance, in recent years, through various mechanisms. The reports on transferable resistance among probiotics are of major concern, of which minimal information is available to date. The aim of this review was to describe the pros and cons of drug resistance among these beneficial microorganisms with emphasis on the recommended selection criteria for specific probiotics, devoid of transferable drug resistance genes, suitable for human consumption.
- Published
- 2020
- Full Text
- View/download PDF
48. Dosimetric perturbations at high-Z interfaces with high dose rate 192Ir source
- Author
-
Indra J. Das and Hualin Zhang
- Subjects
Dose perturbation ,Materials science ,Thin layers ,Phantoms, Imaging ,medicine.medical_treatment ,Brachytherapy ,Monte Carlo method ,Biophysics ,Analytical chemistry ,Water ,General Physics and Astronomy ,Radiotherapy Dosage ,General Medicine ,Iridium Radioisotopes ,Radiation Dosage ,Imaging phantom ,Upstream and downstream (DNA) ,Ionization chamber ,medicine ,Radiology, Nuclear Medicine and imaging ,Radiometry ,Dose rate ,Monte Carlo Method ,Biomedical engineering - Abstract
Purpose To investigate dose perturbations created by high-atomic number ( Z ) materials in high dose rate (HDR) Iridium-192 ( 192 Ir) treatment region. Methods and materials A specially designed parallel plate ion chamber with 5 μm thick window was used to measure the dose rates from 192 Ir source downstream of the high-Z materials. A Monte Carlo (MC) code was employed to calculate the dose rates in both upstream and downstream of the high-Z interfaces at distances ranging from 0.01 to 2 mm. The dose perturbation factor (DPF) was defined as the ratio of dose rate with and without high-Z material in a water phantom. For verifying the Z dependence, both 0.1- and 1.0 mm-thick sheets of Pb, Au, Ta, Sn, Cu, Fe, Ti and Al were used. Results/conclusions The DPF depends on the Z and thickness of layer. At the downstream of a 0.1 mm layer of Pb, Au, Ta, Sn, Cu, Fe, Ti and Al, the DPF by MC were 3.73, 3.42, 3.04, 1.71, 1.04, 0.98, 0.92, or 0.94 respectively. When Z is greater than or equal to 50, the MC and experimental results disagree significantly (>20%) due to large DPF gradient but are in agreement for Z less than or equal to 29. Thin layers of Z greater than or equal to 50 near a 192 Ir source in water produce significant dose perturbations (i.e. increases) in the vicinity of the medium-high-Z interfaces and may thus cause local over-dose in 192 Ir brachytherapy. Conversely, this effect may potentially be used to deliver locally higher doses to targeted tissue.
- Published
- 2014
- Full Text
- View/download PDF
49. Optimization of GATE and PHITS Monte Carlo code parameters for uniform scanning proton beam based on simulation with FLUKA general-purpose code
- Author
-
Indra J. Das, Vadim Moskvin, Keita Kurosu, Masahiko Koizumi, and Masaaki Takashina
- Subjects
Physics ,Imagination ,Nuclear and High Energy Physics ,Range (particle radiation) ,Proton ,media_common.quotation_subject ,Nuclear engineering ,Monte Carlo method ,Imaging phantom ,Search engine ,Particle ,Instrumentation ,Beam (structure) ,media_common - Abstract
Although three general-purpose Monte Carlo (MC) simulation tools: Geant4, FLUKA and PHITS have been used extensively, differences in calculation results have been reported. The major causes are the implementation of the physical model, preset value of the ionization potential or definition of the maximum step size. In order to achieve artifact free MC simulation, an optimized parameters list for each simulation system is required. Several authors have already proposed the optimized lists, but those studies were performed with a simple system such as only a water phantom. Since particle beams have a transport, interaction and electromagnetic processes during beam delivery, establishment of an optimized parameters-list for whole beam delivery system is therefore of major importance. The purpose of this study was to determine the optimized parameters list for GATE and PHITS using proton treatment nozzle computational model. The simulation was performed with the broad scanning proton beam. The influences of the customizing parameters on the percentage depth dose (PDD) profile and the proton range were investigated by comparison with the result of FLUKA, and then the optimal parameters were determined. The PDD profile and the proton range obtained from our optimized parameters list showed different characteristics from the results obtained with simple system. This led to the conclusion that the physical model, particle transport mechanics and different geometry-based descriptions need accurate customization in planning computational experiments for artifact-free MC simulation.
- Published
- 2014
- Full Text
- View/download PDF
50. Diffusion-weighted imaging in urinary tract lesions
- Author
-
Chandan J Das, Vinit Baliyan, Suvasini Sharma, and Arjun Gupta
- Subjects
Male ,Urologic Neoplasms ,medicine.medical_specialty ,Physics of magnetic resonance imaging ,Urinary system ,Contrast Media ,Magnetics ,Renal cell carcinoma ,medicine ,Humans ,Effective diffusion coefficient ,Radiology, Nuclear Medicine and imaging ,Disease process ,cardiovascular diseases ,Urinary Tract ,medicine.diagnostic_test ,business.industry ,Prostatic Neoplasms ,Magnetic resonance imaging ,General Medicine ,Image Enhancement ,medicine.disease ,Kidney Neoplasms ,Diffusion Magnetic Resonance Imaging ,Female ,Kidney Diseases ,Radiology ,business ,Regional differences ,Diffusion MRI - Abstract
Diffusion-weighted imaging (DWI) utilizes the signal contrast provided by the regional differences in the Brownian motion of water molecules, which is a direct reflection of the cellular micro-environment. DWI emerged as a revolutionary magnetic resonance imaging (MRI) technique in the field of stroke imaging. As far as body imaging is concerned, DWI has come a long way from being an experimental technique to an essential element of almost all abdominal MRI examinations. This progress has been made possible by technical advancements in MRI systems, as well as a better understanding of MRI physics. DWI is quick to perform and has the potential to provide crucial information about the disease process without adding much to the total imaging time. This article provides a brief review of the basic principles of DWI with insights to the information that DWI provides in the evaluation of various diseases of the urinary tract at both 1.5 and 3 T. DWI is helpful for differentiation of various histopathological subtypes of renal cell carcinoma (RCC). Prediction of histopathological grade of RCC is also becoming possible solely based on DWI. Assessment of response to chemotherapeutic agents is possible based on the change in the ADC (apparent diffusion coefficient) value. DWI performed with high b-values increases the confidence in diagnosing prostatic carcinoma. This article highlights the emerging role of DWI in the evaluation of urinary tract lesions.
- Published
- 2014
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.