19 results on '"Varun Krishnan"'
Search Results
2. Solving the Ride-Sharing Productivity Paradox: Priority Dispatch and Optimal Priority Sets.
- Author
-
Varun Krishnan, Ramón Iglesias, Sébastien Martin, Su Wang, Varun Pattabhiraman, and Garrett J. van Ryzin
- Published
- 2022
- Full Text
- View/download PDF
3. Analyses and Localization of Phosphatidylcholine and Phosphatidylserine in Murine Ocular Tissue Using Imaging Mass Spectrometry
- Author
-
Varun Krishnan, Sean D. Meehan, Colin Hayter, and Sanjoy K. Bhattacharya
- Published
- 2023
- Full Text
- View/download PDF
4. Analyses and Localization of Serotonin and L-DOPA in Ocular Tissues by Imaging Mass Spectrometry
- Author
-
Varun Krishnan, Sean Meehan, Colin Hayter, and Sanjoy K. Bhattacharya
- Published
- 2022
- Full Text
- View/download PDF
5. Analyses and Localization of Serotonin and L-DOPA in Ocular Tissues by Imaging Mass Spectrometry
- Author
-
Varun, Krishnan, Sean, Meehan, Colin, Hayter, and Sanjoy K, Bhattacharya
- Subjects
Levodopa ,Serotonin ,Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ,Metabolomics ,Lipids - Abstract
Imaging mass spectrometry (IMS) allows for visualization of the spatial distribution of proteins, lipids, and other metabolites in a targeted or untargeted approach. The identification of compounds through mass spectrometry combined with the mapping of compound distribution in the sample establishes IMS as a powerful tool for metabolomics. IMS analysis for serotonin will allow researchers to pinpoint areas of deficiencies or accumulations associated with ocular disorders such as serotonin selective reuptake inhibitor optic neuropathy. Furthermore, L-DOPA has shown great promise as a therapeutic approach for disorders such as age-related macular degeneration, and IMS allows for localization, and relative magnitudes, of L-DOPA in the eye. We describe here an end-to-end approach of IMS from sample preparation to data analysis for serotonin and L-DOPA analysis.
- Published
- 2022
6. Comparative evaluation of microleakage of G-aenial Universal Flo, Smart Dentin Replacement and Tetric Evo Ceram bulk fill resin composite restorations in class v cavity preparation: an in-vitro study
- Author
-
Melwin, Sharath Kumar .P, V P Varun Krishnan, Pulamaghatta N. Venugopal, S Anil Kumar, K N Jyothi, and Sonal Girish
- Subjects
Materials science ,business.industry ,Resin composite ,Group ii ,Significant difference ,Dentistry ,Bulk fill ,Comparative evaluation ,medicine.anatomical_structure ,stomatognathic system ,Stereo microscope ,Dentin ,medicine ,In vitro study ,business - Abstract
Aim and Objective: Was to assess and compare the microleakage of G-aenial Universal Flo, Smart Dentin Replacement and Tetric Evo Ceram bulk fill resin composites in class V cavities along the occlusal and gingival margins using dye penetration test under stereomicroscope. Materials and Methods: Seventy five human extracted premolars were selected and randomly divided into 3 groups (n=25), as per the restorative materials for microleakage test. Group I: Tetric Evo Ceram (Bulk fill non flowable). Group II: G-aenial Universal Flo (Highly filled flowable resin composite). Group III: Smart Dentin Replacement (Bulk fill flowable resin composite). Class V (box) cavities were prepared both on the buccal and lingual surfaces of each of the 75 teeth, a total of 150 cavities, restored, immersed in 2% methylene blue dye for 24 hours and then sectioned bucco lingually into two halves. Dye penetration score was measured along occlusal and gingival wall using a Stereomicroscope at 40X magnification. Statistical analysis was done using Chi square test for microleakage assessment. P value was set at E‚0.05. Result: Intergroup comparison showed statistically no significant difference between the three groups both occlusal and gingival wall, whereas groupwise comparison showed statistically significant result between group I and Group II at gingival wall with P value 0.021. Conclusion: None of three resin composite materials were free from microleakage. All the three materials showed more microleakage at gingival wall compared to occlusal wall. Among all the tested groups G-aenial Universal Flo showed the least microleakage at the gingival wall. Keyword: Microleakage, Class V, Resin composites.
- Published
- 2020
- Full Text
- View/download PDF
7. Mechanism and Effects of Coverage and Particle Morphology on Rh-Catalyzed NO–H2 Reactions
- Author
-
David Hibbitts, Varun Krishnan, and Pavlo Kravchenko
- Subjects
Materials science ,Morphology (linguistics) ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Catalysis ,Nitric oxide ,chemistry.chemical_compound ,General Energy ,Chemical engineering ,chemistry ,Particle ,Physical and Theoretical Chemistry ,0210 nano-technology ,Automotive exhaust ,Mechanism (sociology) - Abstract
Three-way catalysts, which typically include Rh, are used to treat automotive exhaust and reduce nitric oxide (NO) with a combination of CO and H2, although few kinetic and theoretical investigatio...
- Published
- 2020
- Full Text
- View/download PDF
8. A Real-Time Application of Modified Inductor Coupled KY Converter Topology in Speed Control of E-Bikes
- Author
-
K S Varun Krishnan and Preethi Thekkath
- Subjects
Electronic speed control ,Hardware_MEMORYSTRUCTURES ,Computer science ,020209 energy ,Mechanical Engineering ,ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS ,020208 electrical & electronic engineering ,ComputingMilieux_PERSONALCOMPUTING ,Energy Engineering and Power Technology ,Topology (electrical circuits) ,02 engineering and technology ,Inductor ,Throttle ,Mechanism (engineering) ,Control theory ,0202 electrical engineering, electronic engineering, information engineering ,Electrical and Electronic Engineering - Abstract
Congested road network and traffic jam lead to vehicle idling and fuel wastage. An E-bike which is a solution to this is often available with Thumb Throttle Mechanism and single speed operation. A ...
- Published
- 2019
- Full Text
- View/download PDF
9. Minimally Invasive Surgery is Associated with Improved Outcomes Following Urgent Inpatient Colectomy
- Author
-
Luv N, Hajirawala, Varun, Krishnan, Claudia, Leonardi, Elyse R, Bevier-Rawls, Guy R, Orangio, Kurt G, Davis, Aaron L, Klinger, and Jeffrey S, Barton
- Subjects
Inpatients ,Postoperative Complications ,Humans ,Minimally Invasive Surgical Procedures ,Laparoscopy ,Surgery ,Colectomy ,United States - Abstract
The use of minimally invasive techniques for urgent colectomies remains understudied. This study compares short-term outcomes following urgent minimally invasive colectomies to those following open colectomies.The American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) colectomy database was queried between January 1, 2013 and December 31, 2018. Patients who underwent elective and emergency colectomies, based on the respective NSQIP variables, were excluded. The remaining patients were divided into two groups, minimally invasive surgery (MIS) and open. MIS colectomies with unplanned conversion to open were included in the MIS group. Baseline characteristics and 30-day outcomes were compared using univariable and multivariable regression analyses.A total of 29,345 patients were included in the study; 12,721 (43.3%) underwent MIS colectomy, while 16,624 (56.7%) underwent open colectomy. Patients undergoing MIS colectomy were younger (60.6 vs 63.8 years) and had a lower prevalence of either American Society of Anesthesiology (ASA) IV (9.9 vs 15.5%) or ASA V (0.08% vs 2%). After multivariable analysis, MIS colectomy was associated with lower odds of mortality (odds ratio = 0.75, 95% confidence interval: 0.61, 0.91 95% confidence interval), and most short-term complications recorded in the ACS NSQIP. While MIS colectomies took longer to perform (161 vs 140 min), the length of stay was shorter (12.2 vs 14.1 days).MIS colectomy affords better short-term complication rates and a reduced length of stay compared to open colectomy for patients requiring urgent surgery. If feasible, minimally invasive colectomy should be offered to patients necessitating urgent colon resection.
- Published
- 2022
- Full Text
- View/download PDF
10. Clinical significance of crown-like structures to trastuzumab response in patients with primary invasive HER2+ breast cancer
- Author
-
Charles N. Birts, Stephen A. Beers, Peter Johnson, Stéphanie A Laversin, Jamie Varun Krishnan, Jeremy P. Blaydes, Margaret Ashton-Key, Ellen Copson, Ramsey I. Cutress, Alicia Y Lefas, Constantinos Savva, Max Crispin, and Aron Schapira
- Subjects
Oncology ,Cancer Research ,medicine.medical_specialty ,business.industry ,Metabolic reprogramming ,medicine.disease ,Systemic inflammation ,Obesity ,Breast cancer ,Trastuzumab ,Internal medicine ,medicine ,Clinical significance ,In patient ,medicine.symptom ,skin and connective tissue diseases ,business ,medicine.drug - Abstract
e12533 Background: Obesity is associated with breast cancer development and worse survival. Obesity can initiate, promote, and maintain systemic inflammation via metabolic reprogramming of macrophages that encircle adipocytes, termed crown-like structures (CLS). In breast cancer patients, CLS are present in 36-50% of patients and have been associated with anthropometric parameters. Here we focus on HER2+ breast cancer. The role of adiposity in HER2+ breast cancer is conflicting which may be attributed to the tumour heterogeneity. Adiposity has also been shown to affect the local immune environment of solid tumours. However, the prognostic significance of CLS in HER2+ breast cancer is still unknown. Methods: We investigated the prognostic significance of CLS in a cohort of 219 patients with primary HER2+ breast cancer who were diagnosed between 1982 to 2012 in Southampton General Hospital. This cohort includes 76 HER2+ trastuzumab naïve patients and 143 HER2+ patients treated with adjuvant trastuzumab. We stained FFPE tumour samples for the expression of CD68, CD16 and CD32B on CLS and correlated these to clinical outcomes. CLS were defined as CLS within distant adipose tissue, CLS within the adipose-tumour border (B-CLS) and intratumoural CLS. CLS were quantified manually in full face sections by two independent scorers and descriptive and Cox regression analysis was carried out. Results: A total of 201 tumours were suitable for CLS analyses. The median follow-up was 34.74 months (range, 0.43-299.08). In the trastuzumab naive cohort, B-CLS≤1 and B-CLS > 1 were present in 37 (52.11%) and 34 (47.89%), respectively. In the trastuzumab treated cohort, B-CLS≤1 were identified in 69 (53.08%) and B-CLS > 1 were found in 61 (46.92%) of the tumours. CLS were more commonly found in the adipose-tumour border (60.89%) rather than in the distant adipose tissue (36.14%) or intratumorally (14.36%). The presence of any CLS was significantly associated with BMI≥25 kg/m2 (p = 0.018). There was strong evidence of association between CD68+CD32B+ B-CLS and BMI≥25 kg/m2 (p = 0.007). Co-expression of CD16 and CD32B by B-CLS was more frequent in patients with BMI≥25 kg/m2 (p = 0.036). Survival analysis showed shorter time to metastatic disease in patients with CD68+ B-CLS > 1 (p = 0.011) in the trastuzumab treated cohort. Subgroup analysis revealed that in the BMI≥25 kg/m2 group, patients with CD68+ B-CLS > 1 had shorter time to metastatic disease compared to patients with B-CLS≤1 (p = 0.004). Multivariate cox regression showed that B-CLS > 1 is an independent prognostic factor for shorter time to metastatic disease in patients with primary HER2+ breast cancer that received adjuvant trastuzumab (HR 6.81, 95%CI (1.38-33.54), p = 0.018). Conclusions: B-CLS can be potentially used as a predictive biomarker to optimize the stratification and personalisation of treatment in HER2-overexpressed breast cancer patients.
- Published
- 2021
- Full Text
- View/download PDF
11. Time-to-Surgery for Definitive Fixation of Hip Fractures: A Look at Outcomes Based Upon Delay
- Author
-
Matthew D. Beal, Mary J. Kwasny, Hasham M. Alvi, Rachel M. Thompson, David W. Manning, and Varun Krishnan
- Subjects
Male ,medicine.medical_specialty ,Percutaneous ,Time Factors ,Databases, Factual ,Femoral Neck Fractures ,law.invention ,Time-to-Treatment ,Intramedullary rod ,03 medical and health sciences ,0302 clinical medicine ,law ,Fracture Fixation ,Risk Factors ,Fracture fixation ,medicine ,Humans ,030212 general & internal medicine ,Aged ,Retrospective Studies ,Aged, 80 and over ,030222 orthopedics ,Hip fracture ,business.industry ,Hip Fractures ,Mortality rate ,Retrospective cohort study ,Middle Aged ,medicine.disease ,Quality Improvement ,Surgery ,Treatment Outcome ,Current Procedural Terminology ,Female ,business - Abstract
The morbidity and mortality after hip fracture in the elderly are influenced by non-modifiable comorbidities. Time-to-surgery is a modifiable factor that may play a role in postoperative morbidity. This study investigates the outcomes and complications in the elderly hip fracture surgery as a function of time-to-surgery. Using the American College of Surgeons-National Surgical Quality Improvement Program data from 2011 to 2012, a study population was generated using the Current Procedural Terminology codes for percutaneous or open treatment of femoral neck fractures (27235, 27236) and fixation with a screw and side plate or intramedullary fixation (27244, 27245) for peritrochanteric fractures. Three time-to-surgery groups (24 hours to surgical intervention, 24-48 hours, and48 hours) were created and matched for surgery type, sex, age, and American Society of Anesthesiologists class. Time-to-surgery was then studied for its effect on the post-surgical outcomes using the adjusted regression modeling. A study population of 6036 hip fractures was created, and 2012 patients were assigned to each matched time-to-surgery group. The unadjusted models showed that the earlier surgical intervention groups (24 hours and 24-48 hours) exhibited a lower overall complication rate (P = .034) compared with the group waiting for surgery48 hours. The unadjusted mortality rates increased with delay to surgical intervention (P = .039). Time-to-surgery caused no effect on the return to the operating room rate (P = .554) nor readmission rate (P = .285). Compared with other time-to-surgeries, the time-to-surgery of48 hours was associated with prolonged total hospital length of stay (10.9 days) (P.001) and a longer surgery-to-discharge time (hazard ratio, 95% confidence interval: 0.74, 0.69-0.79) (P.001). Adjusted analyses showed no time-to-surgery related difference in complications (P = .143) but presented an increase in the total length of stay (P.001) and surgery-to-discharge time (P.001). Timeliness of surgical intervention in a comorbidity-adjusted population of elderly hip fracture patients causes no effect on the overall complications, readmissions, nor 30-day mortality. However, time-to-surgery of48 hours is associated with costly increase in the total length of stay, including an increased post-surgery-to-discharge time.
- Published
- 2018
12. Long-term outcomes following endoscopic stenting in the management of leaks after foregut and bariatric surgery
- Author
-
Andrew Godwin, Julio Teixeira, Jonathan T Wong, Varun Krishnan, and Kevin Hutchings
- Subjects
Adult ,Male ,Reoperation ,medicine.medical_specialty ,Sleeve gastrectomy ,medicine.medical_treatment ,Gastric Bypass ,Bariatric Surgery ,Anastomotic Leak ,03 medical and health sciences ,0302 clinical medicine ,Postoperative Complications ,Weight loss ,Gastrectomy ,Internal medicine ,Abdomen ,medicine ,Humans ,Endoscopic stenting ,Retrospective Studies ,business.industry ,Reflux ,Stent ,Endoscopy ,Hepatology ,equipment and supplies ,Duodenal switch ,Surgery ,Obesity, Morbid ,Treatment Outcome ,030220 oncology & carcinogenesis ,030211 gastroenterology & hepatology ,Female ,Stents ,medicine.symptom ,business ,Abdominal surgery - Abstract
Endoscopic stenting has been shown to be effective in treating leaks after bariatric surgery. However, concerns remain regarding its long-term efficacy. The purpose of this study was to assess the evolution of endoscopic stenting and its efficacy over time, as well as the impact of stent fixation on migration rates and long-term outcomes. In addition, the effect of stenting on long-term weight loss and chronic reflux was also evaluated. A retrospective review was conducted including 37 patients from 2005 to 2017 who had undergone placement of stents after various bariatric procedures. Stents were placed endoscopically and, after 2012, secured with a figure-of-eight overstitch. Demographics, weight loss data, stent migration rates, incidence of revision surgery, chronic PPI use, and chronic symptoms of reflux data were obtained and analyzed. Thirty-seven patients from 2005 to 2017 required endoscopic stenting for leaks. 43.24% patients underwent sleeve gastrectomy, 40.54% gastric bypass, 5.40% patients underwent duodenal switch, and 10.81% underwent miscellaneous foregut procedures. The overall success rate was 94.59% (35 of 37 patients). The incidence of stent migration before 2012 was 41.18% versus 15% after 2012 (p = 0.136271). There were 2 treatment failures, one treated successfully with re-stenting and another other requiring revision surgery. Overall, the percent of excess body weight lost was 57.21% over an average of 21 months. 58.82% of patients used PPI chronically; however 41.17% noted actual symptoms of reflux. 16.22% (6 of 37) patients ultimately underwent revision surgery. Endoscopic stenting is a safe and effective treatment for leaks after bariatric surgery. While complications can include stent migration, newer stent technology and endoscopic overstitching techniques show promise in reducing the incidence of stent migration. Despite undergoing treatment with stenting, these patients had successful weight loss with relatively low rates of chronic PPI use and reflux symptoms.
- Published
- 2018
13. The Effect of BMI on 30 Day Outcomes Following Total Joint Arthroplasty
- Author
-
Varun Krishnan, Rachel E. Mednick, Matthew D. Beal, David W. Manning, Hasham M. Alvi, and Mary J. Kwasny
- Subjects
medicine.medical_specialty ,Joint arthroplasty ,Demographics ,business.industry ,medicine.medical_treatment ,medicine.disease ,Arthroplasty ,Wound infection ,Obesity ,Surgery ,Acs nsqip ,Risk stratification ,Medicine ,Orthopedics and Sports Medicine ,business - Abstract
Hip and knee arthroplasty (THA, TKA) are safe, effective procedures with reliable, reproducible outcomes. We aim to investigate obesity's effect on complications following arthroplasty surgery. Using the American College of Surgeons-National Surgical Quality Improvement Program database, 13,250 subjects were stratified into 5 groups based on BMI and matched for gender, age, surgery type and ASA class. Matched, multivariable generalized linear models adjusting for demographics and comorbidities demonstrated an association between elevated BMI and overall (P
- Published
- 2015
- Full Text
- View/download PDF
14. A137 Revisional bariatric surgery to treat recurrent diabetes and pre-diabetes – positive metabolic effect in 60 patients
- Author
-
Varun Krishnan, Dimitar Ranev, Filippo Filicori, Julio Teixeira, Jacqueline Duarte Fernandes, and Megan Pandorf
- Subjects
medicine.medical_specialty ,business.industry ,Pre diabetes ,Metabolic effects ,Diabetes mellitus ,medicine ,Surgery ,medicine.disease ,business - Published
- 2019
- Full Text
- View/download PDF
15. The Safety and Efficacy of Endoscopic Stenting in the Management of Leaks: A Longitudinal Evaluation
- Author
-
Julio Teixeira and Varun Krishnan
- Subjects
medicine.medical_specialty ,business.industry ,Medicine ,Surgery ,Endoscopic stenting ,business - Published
- 2017
- Full Text
- View/download PDF
16. The Impact of Revision Bariatric Surgery on Comorbidities
- Author
-
Varun Krishnan, Kevin Hutchings, Andrew Godwin, and Julio Teixeira
- Subjects
medicine.medical_specialty ,business.industry ,medicine ,Surgery ,business - Published
- 2018
- Full Text
- View/download PDF
17. Three years of experience with a novel 'virtual' pneumonia follow-up clinic
- Author
-
Ben G. Marshall, Christopher R Wilcox, Jamie Varun Krishnan, and Claire Duffus
- Subjects
Male ,Pulmonary and Respiratory Medicine ,Pediatrics ,medicine.medical_specialty ,Quality management ,MEDLINE ,Aftercare ,Patient care ,03 medical and health sciences ,0302 clinical medicine ,Ambulatory care ,Ambulatory Care ,medicine ,Humans ,030212 general & internal medicine ,Lung ,Aged ,Aged, 80 and over ,Patient discharge ,business.industry ,Pneumonia ,medicine.disease ,Quality Improvement ,Patient Discharge ,United Kingdom ,Community-Acquired Infections ,Radiography ,030228 respiratory system ,Female ,Medical emergency ,business - Abstract
A virtual pneumonia follow-up service provides significant efficiency savings and retains high quality patient care http://ow.ly/AUov30dRIXe
- Published
- 2017
- Full Text
- View/download PDF
18. Factors Affecting Readmission Rates Following Primary Total Hip Arthroplasty
- Author
-
David W. Manning, Francis Lovecchio, Varun Krishnan, Rachel E. Mednick, and Hasham M. Alvi
- Subjects
Male ,medicine.medical_specialty ,medicine.medical_treatment ,Arthroplasty, Replacement, Hip ,Lower risk ,Patient Readmission ,Risk Assessment ,Postoperative Complications ,Risk Factors ,medicine ,Humans ,Orthopedics and Sports Medicine ,Aged ,business.industry ,General Medicine ,Odds ratio ,Middle Aged ,medicine.disease ,Comorbidity ,Arthroplasty ,Confidence interval ,United States ,Surgery ,Pulmonary embolism ,Current Procedural Terminology ,Female ,Hip Joint ,Joint Diseases ,business ,Body mass index - Abstract
Background: Readmissions following total hip arthroplasty are a focus given the forthcoming financial penalties that hospitals in the United States may incur starting in 2015. The purpose of this study was to identify both preoperative comorbidities and postoperative conditions that increase the risk of readmission following total hip arthroplasty. Methods: Using the American College of Surgeons–National Surgical Quality Improvement Program data for 2011, a study population was identified using the Current Procedural Terminology code for primary total hip arthroplasty (27130). The sample was stratified into readmitted and non-readmitted cohorts. Demographic variables, preoperative comorbidities, laboratory values, operative characteristics, and surgical outcomes were compared between the groups using univariate and multivariate logistic regression models. Results: Of the 9441 patients, there were 345 readmissions (3.65%) within the first thirty days following surgery. Comorbidities that increased the risk for readmission were diabetes (p < 0.001), chronic obstructive pulmonary disease (p < 0.001), bleeding disorders (p < 0.001), preoperative blood transfusion (p = 0.035), corticosteroid use (p < 0.001), dyspnea (p = 0.001), previous cardiac surgery (p = 0.002), and hypertension (p < 0.001). A multivariate regression model was used to control for potential confounders. Having a body mass index of ≥40 kg/m2 (odds ratio, 1.941 [95% confidence interval, 1.019 to 3.696]; p = 0.044) and using corticosteroids preoperatively (odds ratio, 2.928 [95% confidence interval, 1.731 to 4.953]; p < 0.001) were independently associated with a higher likelihood of readmission, and a high preoperative serum albumin (odds ratio, 0.688 [95% confidence interval, 0.477 to 0.992]; p = 0.045) was independently associated with a lower risk for readmission. Postoperative surgical site infection, pulmonary embolism, deep venous thrombosis, and sepsis (p < 0.001) were also independent risk factors for readmission. Conclusions: The risk of readmission following total hip arthroplasty increases with growing preoperative comorbidity burden, and is specifically increased in patients with a body mass index of ≥40 kg/m2, a history of corticosteroid use, and low preoperative serum albumin and in patients with postoperative surgical site infection, a thromboembolic event, and sepsis. Level of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.
- Published
- 2014
19. A study of macrophage activatory to inhibitory FcɣR ratio in HER2+ breast cancer
- Author
-
Ellen Copson, Ramsey I. Cutress, Stephen A. Beers, Stéphanie A Laversin, Jamie Varun Krishnan, and Aron Schapira
- Subjects
Breast cancer ,Oncology ,business.industry ,Cancer research ,Medicine ,Macrophage ,Surgery ,General Medicine ,business ,Inhibitory postsynaptic potential ,medicine.disease - Published
- 2013
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.