74 results on '"Sandip Sarkar"'
Search Results
2. Cancer model and its possible control—A Z-type control approach
- Author
-
Sudip Samanta, Sandip Sarkar, and Kaushik Kayal
- Subjects
Z-type control method ,Science - Abstract
This paper investigates the dynamics of a three-dimensional nonlinear cancer model involving interactions among cancer cells, normal cells, and immune cells. By performing a linear stability analysis of the equilibria and investigating the Hopf bifurcation in relation to the immune cell growth rate, we reveal the possibility of chaotic behavior when radiation is absent. However, with the appropriate implementation of radiotherapy, the cancer model demonstrates stable solutions, transitioning from chaotic oscillations through period-halving bifurcation. Additionally, we propose and examine an indirect Z-control mechanism within the cancer model. Our findings indicate that using the indirect Z-controller on the immune population successfully manages chaos and adjusts the cancer cell density to a desired level. Through extensive investigation, we demonstrate the robustness of the Z-controller in managing oscillations and provide insights into determining the minimum number of immune cells needed to achieve a predetermined cancer cell density. This study underscores the importance of control mechanisms in mitigating cancer progression and highlights the potential of Z-control for therapeutic intervention strategies.
- Published
- 2024
- Full Text
- View/download PDF
3. Female body-corporeal as both the aetiological site and the site of resistance: Conceptualizing manic depression in Jerry Pinto's Em and the Big Hoom
- Author
-
Sayan Das, Md Moshabbir Alam, and Sandip Sarkar
- Subjects
Body-corporeal ,Gender scripting ,Abject ,Self-harm ,Resistance ,History of scholarship and learning. The humanities ,AZ20-999 ,Social sciences (General) ,H1-99 - Abstract
The hegemonic discourse of normalcy perpetuates unfavourable portrayals of mental illness; it distorts our understanding of the sufferer's existential and affective experiences. However, mental illness is a multifaceted phenomenon; it necessitates a holistic understanding of how an individual's identity and personhood are emplaced at the intersection of the diverse sociocultural conditions. The article conceptualizes manic depression as a complex interplay of the corporeal, cognitive, and cultural factors in Jerry Pinto's critically acclaimed contemporary novel Em and the Big Hoom (2012). Jerry Pinto is a Mumbai-based Goanese Indian author who embarks on exploring the intricacies of psychological vulnerabilities and draws heavily from his personal experiences to write poignant, humane and empathetic stories. Em and the Big Hoom documents the narrator's reminiscences of his late mother, Em or Imelda's experiences of mood swings, paranoid delusions, freakish breakdowns, and psychiatric treatments. It scrutinizes extracts of Em's diary notes, letters, and past conversations to exhibit how a woman succumbs to abjection due to socio-cultural expectations of sex, pregnancy, and childbirth and eventually resorts to self-harm. The article projects the female body-corporeal as both the aetiological site and the site of resistance; while phallocentric cartography of the female body engenders abjection, manifestations of abjection at the corporeal level formulate tropes of resistance. The article challenges the phallocentric tendency to pathologize deviant body-behaviour motifs in women, contributing to the expanding corpus of phenomenological knowledge on pathologized female subjectivities.
- Published
- 2024
- Full Text
- View/download PDF
4. Observing temporal variation in hemolysis through photoacoustics with a low cost LASER diode based system
- Author
-
Soumyodeep Banerjee, Sandip Sarkar, Shaibal Saha, Sumit K. Hira, and Subhajit Karmakar
- Subjects
Medicine ,Science - Abstract
Abstract Patients under hemolytic condition need continuous monitoring of lysis as depletion of Red Blood Cells (RBC) and the presence of antioxidant free hemoglobin (Hb) in excess amount due to hemolysis lead to severe deterioration of their health. Out of many modalities, Photoacoustics (PA) offers real time information noninvasively from deep lying blood vessels since Hb is the strongest chromophore in mammalian blood and the PA response of blood varies with the amount of Hb present. During hemolysis, total Hb content in blood however remains unchanged, thus, questions the use of PA in hemolysis detection. In this report, a hypothesis that the amplitude of the PA signal would not change with the amount of lysis is framed and tested by applying osmotic shock to the RBCs in hypotonic environment and the PA response is recorded over time using a low cost NIR based PA system. The experimental outcome indicates that PA amplitude falls off as lysis progresses in course of time consequently rejecting the hypothesis. The decaying PA response also carries the signature of RBC swelling during the early phase of lysis. The PA measurement can detect hemolysis as low as 1.7%. These findings further advocate transforming this NIR-PA system into a portable, noninvasive patient care device to monitor hemolysis in-vivo.
- Published
- 2023
- Full Text
- View/download PDF
5. A tale of two discs- normal to blurry, and the diagnostic dilemma! How to proceed?
- Author
-
Amit Kumar Deb, Sandip Sarkar, Ninan Jacob, Shreyas Temkar, and Anureet Kaur
- Subjects
Ophthalmology ,RE1-994 - Published
- 2024
- Full Text
- View/download PDF
6. Development of prediction model for mean parotid dose of HNC undergoing radiotherapy - A single institutional study
- Author
-
Soumen Bera, Dipika Choudhury, Sanjoy Roy, Partha Mukhopadhyay, and Sandip Sarkar
- Subjects
organs-at-risk dose prediction ,parotid gland sparing ,prediction model ,volumetric-modulated arc therapy ,Medical physics. Medical radiology. Nuclear medicine ,R895-920 - Abstract
Aim: The aim of the study was to develop a simple prediction model based on previous treatment plans for head-and-neck cancer (HNC). Materials and Methods: This study was conducted on 95 patients who underwent volumetric-modulated arc therapy (VMAT) with curative intent for HNC at our institute between January 2016 and December 2022 with intact bilateral parotid glands. Two simple prediction models were used: one linear regression model and one exponential model. Both models use fractional overlapping parotid volume with planning target volume (PTV) as a predictor of mean parotid dose. The fractional overlapping volume was calculated as the difference between the volume of the parotid gland minus the volume of the parotid gland outside the PTV plus a 2 mm margin, divided by the volume of the parotid gland. Statistical calculations were done using data analysis tools and Solver in Microsoft Excel (Microsoft Office 2013, Redmond, WA, USA). To enhance the accuracy of the results, outliers were excluded with residuals >2 standard deviations below and above the residuals. R2 and root-mean-square error were calculated for both models to evaluate the quality of the predictions. The normality of both models' residuals was validated using the Shapiro–Wilk test. Results: Both linear and exponential prediction models exhibited strong correlation statistics, with r2 = 0.85 and 0.82, respectively. The authors found a fractional overlap of 16.4% and 18.9% in linear and exponential models that predict parotid mean dose 26 Gy. The implementation was carried out on a cohort of 12 prospective patients, demonstrating a remarkable improvement in minimizing the dose to the parotid glands. Conclusion: In this single-institutional study, the authors successfully developed a prediction model for mean parotid dose in HNC patients undergoing radiotherapy. The model showed promising accuracy and has the potential to assist planners in optimizing treatment plans and minimizing radiation-related toxicity. It is possible to avoid under sparing the organs at risks in some cases and wasting time or effort on physically impossible goals in others using this prediction model. As a result, planning resources can be used much more efficiently. Future studies should focus on validating the model's performance using external datasets and exploring its integration into clinical practice.
- Published
- 2023
- Full Text
- View/download PDF
7. Assessment of right atrial function in inferior wall AMI
- Author
-
Abhijit Das, Lipika Adhikari, and Sandip Sarkar
- Subjects
acute myocardial infarction ,inferior wall acute myocardial infarction ,right ventricular myocardial infarction ,non-st elevation myocardial infarction ,right atrium ,right ventricle ,echocardiography ,Medicine - Abstract
Background: Approximately 30–50% of patients with inferior infarction have some involvement of the right ventricle. The right ventricular (RV) infarction almost invariably develops in association with a large infarction of the adjacent septum and inferior 0 walls, but isolated infarction of the right ventricle is seen in just 3–5% of autopsy-proven cases of MI. This study is designed to assess the right atrial (RA) functions in inferior wall acute myocardial infarction (AMI) (IWMI) echocardiographically and to compare it with patients who do not have history of ischemic heart disease (IHD) but having risk factors for IHD. Aims and Objectives: The aims of this study were to study the patients presenting with Inferior wall MI IWMI for RA function. Materials and Methods: Patients admitted in the Cardiology ward of R G Kar Medical College and Hospital with IWMI from March 2020 to March 2022 were included in the study. Results: Average Measurement of RA volume index (RAVI) and RA Pressure (RAP) was highest among patients with IWMI+RV myocardial infarction (RVMI). Out of 100 IWMI patients, 33 had high RAVI and RAP and out of 100 non-IHD patients none had high RAVI. Conclusion: In our study, there was no statistically significant difference in average RAVI and RAP in patients presenting with IWMI and in patients with risk factors for myocardial infarction but without AMI. However, patients presented with IWMI+RVMI showed statistically significant increased RAVI and RAP as compared to inferior wall AMI only.
- Published
- 2022
- Full Text
- View/download PDF
8. Pregnancy outcome in patients presented with Peripartum Cardiomyopathy: A five-year study in a tertiary care centre
- Author
-
Lipika Adhikari and Sandip Sarkar
- Subjects
peripartum cardiomyopathy(ppcm) ,left ventricular ejection fraction(lvef) ,left ventricular internal diameter in diastole(lvidd) ,new york heart association(nyha) ,pregnancy induced hypertension(pih) ,coronary artery disease(cad) ,chronic kidney disease(ckd) ,intrauterine growth restriction(iugr) ,Medicine - Abstract
Background: Peripartum cardiomyopathy is a relatively rare type of dilated cardiomyopathy that presents in late pregnancy or the early postpartum period. Although the condition is prevalent worldwide, women with black genealogy seem to have greater risk. Possible other risk factors are elderly maternal age, hypertension, multiparity, multifetal pregnancy etc. Although the pathophysiology of peripartum cardiomyopathy is still obscure, recent studies suggests the important role of vasculo-hormonal pathway along with several other possible factors e.g. myocarditis, abnormal immune response to pregnancy, abnormal response to increased hemodynamic burden, malnutrition, inflammation and apoptosis . Aims and Objectives: To find out the prevalence, risk factors and pregnancy outcome of peripartum cardiomyopathy (PPCM) Materials and Methods: Sixty-eight patients of PPCM admitted in G&O department of RG KAR Medical college were taken. Clinical evaluations, Hematological evaluation, biochemical study, ECG and Echocardiography were done. Patient outcome was also compared between two groups of patients having Left Ventricular ejection fraction less than 35% and more than 35%. Result: Prevalence of PPCM was 0.09%, maternal mortality was 87 per 1000 live births and perinatal mortality was 43 per 1000 live births. Patients with lower ejection fraction showed poorer outcome. Conclusion: Patients with higher NYHA functional class, lower ejection fraction and larger left ventricular cavity showed worse maternal and perinatal outcome.
- Published
- 2022
- Full Text
- View/download PDF
9. Study of anxiety in patients with glaucoma undergoing standard automated perimetry and optical coherence tomography - A prospective comparative study
- Author
-
Subashini Kaliaperumal, V S Janani, Vikas Menon, Sandip Sarkar, Geeta Behera, and Shivanand Kattamani
- Subjects
anxiety ,glaucoma ,optical coherence tomography (oct) ,state-trait anxiety inventory [stai] ,visual field testing ,Ophthalmology ,RE1-994 - Abstract
Purpose: To compare the anxiety levels related to visual field testing and optical coherence tomography (OCT) in patients with glaucoma. Methods: This prospective, comparative study was conducted on patients with glaucoma. The participants' anxiety traits were assessed using the State-Trait Anxiety Inventory [STAI]. Before visual field testing on Humphrey visual field analyzer (HVF) and retinal nerve fiber analysis on OCT, the participants completed Form Y1 to measure the current pretest level or 'State' anxiety [pretest anxiety]. Immediately after testing, participants were administered the Form Y1 questionnaire to assess the induced anxiety level during the testing [Intratest anxiety]. Results: A total of 228 patients were enrolled with 152 participants in the HVF group and 76 in the OCT group. The mean age of the participants in the HVF group was 57.2 ± 20.8 years and in the OCT group was 56.8 ± 20 years. There was no significant difference in trait and pretest anxiety between the HVF group and the OCT group (P = 0.971 and P = 0.716). Intratest test anxiety score was slightly higher in the HVF group (HVF: 42.13 ± 10.63, OCT: 40.71 ± 9.76; P = 0.33). The anxiety scores were higher when the experience of previous HVF tests was
- Published
- 2022
- Full Text
- View/download PDF
10. Ophthalmology practice in COVID-19 pandemic: Performance of rapid antigen test versus real time-reverse transcription polymerase chain reaction in a tertiary eye care institute in South India
- Author
-
Sandip Sarkar, Amit Kumar Deb, Rakesh Singh, Rahul Dhodapakar, Tanmay Gokhale, and Subashini Kaliaperumal
- Subjects
covid-19 ,ophthalmic surgery ,rapid antigen test ,rt-pcr ,Ophthalmology ,RE1-994 - Abstract
Purpose: To assess the rapid antigen test (RAT) against the gold standard reverse transcription-polymerase chain reaction (RT-PCR) to screen COVID-19 infection in asymptomatic patients undergoing ophthalmic procedures. Methods: This was a retrospective hospital-based study. Point-of-care (PoC) RAT was performed using nasopharyngeal swab, while RT-PCR for SARS-CoV-2 viral RNA was performed using both nasopharyngeal and throat swabs. Results: A total of 629 patients were tested for SARS-CoV-2 by using both RAT and RT-PCR. Only one patient had tested positive for SARS-CoV-2 with both RAT and RT-PCR, while two patients had tested positive with RT-PCR after an initial negative RAT. The positivity rate for RAT was 0.15% (1/629), and that for RT-PCR was 0.47%. Percent agreement or proportion of agreement observed between the two tests was 99.68%, while Cohen's kappa coefficient value was 0.49. The sensitivity of RAT in comparison to RT-PCR was 33.33%, specificity was 100%, positive predictive value was 100%, and negative predictive value was 99.68%. Conclusion: The sensitivity and Cohen's kappa coefficient in our study were low but that can be attributed to the overall low positivity rates with both RAT and RT-PCR. However, percent agreement observed between the two tests was very high. Therefore, we recommend initial screening of all the patients for COVID-19 symptoms followed by RAT before performing any ophthalmic surgical procedure to ensure the safety of the health care professionals as well as the patients.
- Published
- 2022
- Full Text
- View/download PDF
11. Zero Phaco: A new technique for dealing with soft cataracts
- Author
-
Narayan Bardoloi, Sandip Sarkar, and Roshni Dholkawala
- Subjects
high vacuum ,phacoemulsification ,soft cataract ,zero energy ,Ophthalmology ,RE1-994 - Abstract
Phacoemulsification in soft cataracts can be challenging due to the lack of rigid cleavage planes and the inability to crack. We describe a new phacoemulsification technique for dealing with soft cataracts using high vacuum and zero energy. Following capsulorhexis and hydrodissection, we introduced the phacoemulsification probe, keeping the torsional and longitudinal power at zero. A central groove was created in sculpting mode. We held the nucleus with adequate vacuum in chop mode and divided the nucleus. Then, we rotated and chopped the nucleus similarly into small pieces without using any power. For emulsification, we increased the vacuum to 600 mmHg and then shredded and stuffed the pieces into the phaco probe by the chopper. A newer generation phaco machine with active fluidic system and monitored pressurized infusion helps the surgeon control the intraocular pressure (IOP) and hold the nucleus with vacuum alone, allowing chopping and emulsifying of the pieces without any energy.
- Published
- 2022
- Full Text
- View/download PDF
12. Clinical profile, visual outcome and root cause analysis of post-operative cluster endophthalmitis due to Burkholderia cepacia complex
- Author
-
Amit Kumar Deb, Pratima Chavan, Subashini Kaliaperumal, Sujatha Sistla, Haritha Madigubba, Sandip Sarkar, and Aswathi Neena
- Subjects
burkholderia cepacia complex ,cluster endophthalmitis ,postoperative endophthalmitis ,root cause analysis ,Ophthalmology ,RE1-994 - Abstract
Purpose: To present varied clinical presentations, surveillance reports, and final visual outcomes of a rare outbreak of cluster endophthalmitis caused by gram-negative, opportunistic bacilli, Burkholderia cepacia complex (Bcc). Methods: Details of five patients who developed postoperative cluster endophthalmitis were collected. For each patient, an undiluted vitreous sample was collected during vitreous tap. Bacterial culture from the vitreous sample in each case had grown Bcc. Surveillance investigations for root cause analysis (RCA) were performed in the operating room (OR), admission, and day-care wards to localize the source. Results: Four patients had undergone phacoemulsification surgery, and one patient had undergone penetrating keratoplasty. Each patient received an initial dose of empiric intravitreal ceftazidime and vancomycin. The organism isolated in each case was sensitive to ceftazidime, cotrimoxazole, and meropenem and resistant to other antibiotics. Core vitrectomy was done after 48–60 hours in four patients along with intravitreal imipenem injection. One patient did not provide consent for core vitrectomy and subsequently developed phthisis bulbi. Three patients had subsequent recurrences. Two patients had a final BCVA of 20/60, two had BCVA better than 20/200, while one patient had no perception of light. None of the surveillance samples from the OR complex could isolate Burkholderia. Conclusion: Extensive OR surveillance should be done to identify the potential source of infection. However, the source may not be identifiable in few instances like in our case. Longer follow-up is recommended in cases of Bcc endophthalmitis due to the persistent nature of the infection.
- Published
- 2022
- Full Text
- View/download PDF
13. COVID-19-associated optic neuritis – A case series and review of literature
- Author
-
Ajax Jossy, Ninan Jacob, Sandip Sarkar, Tanmay Gokhale, Subashini Kaliaperumal, and Amit K Deb
- Subjects
covid-19 ,myelin oligodendrocyte glycoprotein ,neuroophthalmic manifestation ,optic neuritis ,Ophthalmology ,RE1-994 - Abstract
Neuroophthalmic manifestations are very rare in corona virus disease-19 (COVID-19) infection. Only few reports have been published till date describing COVID-19-associated neuroophthalmic manifestations. We, hereby, present a series of three cases who developed optic neuritis during the recovery period from COVID-19 infection. Among the three patients, demyelinating lesions were identified in two cases, while another case was associated with serum antibodies against myelin oligodendrocyte glycoprotein. All three patients received intravenous methylprednisolone followed by oral steroids according to the Optic Neuritis Treatment Trail ptotocol. Vision recovery was noted in all three patients, which was maintained at 2 months of the last follow up visit.
- Published
- 2022
- Full Text
- View/download PDF
14. Comparison of once daily dose of 0.3% nepafenac alone and three times dose of 0.1% nepafenac alone in pain and inflammation control after phacoemulsification
- Author
-
Narayan Bardoloi, Sandip Sarkar, Pankaj Suresh Burgute, Amit Kumar Deb, Roshni Dholkawala, Priyal Aggarwal, and Tanmay Gokhale
- Subjects
inflammation ,macular thickness ,nepafenac ,phacoemulsification ,prednisolone ,Ophthalmology ,RE1-994 - Abstract
Purpose: To compare the efficacy of a once-daily dose of 0.3% nepafenac and three times daily dose of 0.1% nepafenac in controlling pain and inflammation following phacoemulsification. Methods: In this prospective randomized control single-blind study. patients who underwent uneventful phacoemulsification were divided into two groups. Group A received 0.1% nepafenac eye drops three times/day for 4 weeks and group B received 0.3% nepafenac eye drops once daily for 4 weeks following phacoemulsification. All the patients received moxifloxacin 0.5% eye drops four times/day for 2 weeks. None of the patients in any group received any form of corticosteroids. Results: The mean age of the patients in group A was 63.55 ± 8.5 years, while in group B, it was 60.05 ± 7.76 years. There was no significant result in the preoperative baseline demographics and intraoperative parameters between both the groups. The results were statistically insignificant in terms of inflammatory markers between both groups on day 1. But, on day 7, group B showed better results in terms of lid edema, conjunctival congestion, and anterior chamber cells. The patients in group B also perceived significantly less pain on day 1 (P = 0.02) and day 7 (P < 0.001). The central macular thickness was also significantly lower in group B at day 30 (P < .001) and day 90 (P < .001), respectively. Conclusion: Once-daily dose of higher concentrated nepafenac (0.3%) is equally effective and shows better results than 0.1% nepafenac for pain and inflammation control.
- Published
- 2022
- Full Text
- View/download PDF
15. Optic nerve demyelination as the presenting feature of adrenoleukodystrophy in a child
- Author
-
Nirupama Kasturi, Sandip Sarkar, Tanmay Gokhale, Chinnaiah G Delhikumar, and Midhusha R Vendoti
- Subjects
adrenoleukodystrophy ,optic nerve demyelination ,very-long-chain fatty acids ,Ophthalmology ,RE1-994 - Published
- 2022
- Full Text
- View/download PDF
16. Primary Ewing's sarcoma of the ethmoid sinus with orbital extension in a young child: A rare case and review of literature
- Author
-
Nirupama Kasturi, Sandip Sarkar, Tanmay Gokhale, and Rajesh Nachiappa Ganesh
- Subjects
ethmoid sinus ,ewing sarcoma ,orbital extension ,Ophthalmology ,RE1-994 - Published
- 2022
- Full Text
- View/download PDF
17. Branch retinal artery occlusion as an initial ocular manifestation of severe iron deficiency anemia: A rare case report
- Author
-
Amit Kumar Deb, Swathi Subramaniam, Sandip Sarkar, Sangaraju Suneel, Vignesh Elamurgan, and Subashini Kaliaperumal
- Subjects
anemic retinopathy ,branch retinal artery occlusion ,iron deficiency anemia ,Ophthalmology ,RE1-994 - Abstract
Ocular manifestations of anemia include conjunctival pallor, retinal hemorrhages, cotton wool spots, Roth spots, subhyaloid hemorrhage, venous dilatation, disc edema, and anterior ischemic optic neuropathy (AION). Retinal arterial occlusion is a very rare complication of iron deficiency anemia. We, hereby, report such a rare case of branch retinal artery occlusion (BRAO) occurring as a complication of iron deficiency anemia. A 49-year-old female presented with sudden painless diminution of vision in her right eye (RE) for 2 weeks with visual acuity of 20/120 in the affected eye and 20/20 in the left eye. Fundus examination of RE showed disc pallor, arteriolar attenuation, and retinal whitening at macula. Fluorescein angiography study demonstrated delayed filling of superotemporal branch of retinal artery, suggesting BRAO as the cause of vision loss. Thorough evaluation for underlying etiology revealed severe iron deficiency anemia (hemoglobin 3.9 g/dl). Her blood pressure, blood sugar profile, lipid profile, carotid Doppler, echocardiogram, coagulation profile, and immunological workup were all unremarkable. She was treated with packed cell transfusion and oral iron supplementation, and her vision improved to 20/40 at 1-month follow-up. Retinal vascular occlusions can occur rarely in iron deficiency anemia, and therefore anemia should be considered, while evaluation of vascular occlusion – specially in those with associated conjunctival pallor as in our case.
- Published
- 2022
- Full Text
- View/download PDF
18. Dosimetric validation of two different radiobiological models for parotid gland functionality of tongue cancer
- Author
-
Srimanta Pramanik, Soumen Bera, Sanjoy Roy, Amitabh Ray, Sandip Sarkar, and Dipanjan Majumder
- Subjects
effective volume ,equivalent uniform dose ,Lyman–Kutcher–Burman model ,normal tissue complication probability ,radiobiological model ,Medical physics. Medical radiology. Nuclear medicine ,R895-920 ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
Abstract Objective The aim of this study was to investigate the normal tissue complication probability (NTCP) for parotid gland of ca tongue patients from two different radiobiological models and to establish a dosimetric validity. Methods Lyman–Kutcher–Burman (LKB) model and linear quadratic (LQ) model were considered for determination of NTCP and tolerance dose (TD5/5 and TD50/5) for the parotid gland of 67 number of ca tongue patients who were treated with the volumetric arc therapy (VMAT) technique. An in‐house developed software on Excel (VBA) was used for this study. Results The equivalent uniform dose (EUD) was linearly proportional to the effective volume (veff) for parotid glands and there was a strong correlation between EUD and veff. At EUD = 46 to 47 Gy, the NTCP of parotid was 0.5 for both the models. The tolerance doses, TD5/5 (veff) and TD50/5 (veff) were exponentially reduced with increase of veff for LKB model; whereas these parameters were volume‐independent in the LQ model. TD5/5 (veff) and TD50/5 (veff) were 31.98 Gy and 45.98 Gy respectively for all 67 patients in the LQ model. Below TD50/5, NTCP of LKB model was less than the NTCP , calculated from LQ model. Conclusion One may consider radiobiological LQ model for estimation of clinical tolerance dose for OARs. Due to lack of clinical data, there are inaccuracy in determination of NTCP from LQ model. If sufficient number of tolerance data for partial volumes are available, the prediction of NTCP would be more confident.
- Published
- 2021
- Full Text
- View/download PDF
19. Capsular tension ring assisted phacoemulsification of morgagnian cataract
- Author
-
Narayan Bardoloi, Sandip Sarkar, Pankaj Suresh Burgute, Debaruna Ghosh, and Amit Kumar Deb
- Subjects
capsular tension ring ,morgagnian cataract ,phacoemulsification ,Ophthalmology ,RE1-994 - Abstract
Purpose: To describe a novel technique of phacoemulsification in morgagnian cataract using capsular tension ring (CTR). Methods: This was a retrospective, non-comparative, clinical interventional study. Patients with hypermature morgagnian cataract who had undergone CTR-assisted phacoemulsification were included in the study. After capsulorhexis, CTR was inserted in a clockwise manner to stabilize the capsular bag in each case. Phacoemulsification was then performed using either horizontal chopping or vertical chopping. We have used the CTR in these cases without any obvious lens subluxation in order to perform safe emulsification of the nuclear pieces in the capsular bag. We have performed the procedure successfully in eleven eyes with hypermature morgagnian cataract. Results: The mean corrected distance visual acuity (CDVA) improved from 2.62 ± 0.25 Log MAR to 0.35 ± 0.28 Log MAR at 3 months postoperatively (P = 0.00008). Total nine out of 11 patients gained CDVA of 20/40 or better at 3 months postoperatively. No intraoperative complications such as posterior capsular rupture, zonular dialysis, iris trauma, vitreous loss were noted. The mean endothelial cell loss was 148.82 ± 41.52 cells/mm2 after 3 months of surgery. Conclusion: The main culprit for intraoperative complications during phacoemulsification in a morgagnian cataract is the vulnerable capsular bag. Following insertion of a CTR after capsulorhexis, the bag becomes stable and the subsequent steps of the surgery become uneventful, thereby, preventing any further complications.
- Published
- 2021
- Full Text
- View/download PDF
20. A new technique of phacoemulsification without hydroprocedures
- Author
-
Narayan Bardoloi and Sandip Sarkar
- Subjects
chopping ,cortical cleavage hydrodissection ,hydroprocedure ,phacoemulsification ,Ophthalmology ,RE1-994 - Abstract
Purpose: We describe a new technique where phacoemulsification can be safely performed without doing hydroprocedure. Materials and Methods: We conducted a prospective, nonrandomized, noncomparative, single-center study where Group A had undergone phacoemulsification without hydroprocedure and Group B had undergone conventional phacoemulsification. After capsulorhexis, we insert the phacoemulsification tip into the eye without doing any hydroprocedure. First shaving of the cortex and epinucleus is done within the capsulorhexis area. Then, the tip is buried into the center of the nucleus and an anteroposterior crack is fashioned. Then, the tip is placed at 8 o'clock position to chop away a piece of nucleus and emulsified. A similar maneuver is done at 4 o'clock position. The phacoemulsification tip and the chopper are now positioned at the cracked site of the lower fragments. Using the two instruments, the fragments are pushed to the opposite direction and emulsified. Results: The mean age of the patients of Group A was 65.7 ± 8.16 years and Group B was 68.9 ± 9.85 years (P = 0.127). The mean best-corrected visual acuity in Group A improved from 0.92 ± 0.49 logarithm of the minimum angle of resolution (logMAR) to 00.01 ± 0.02 logMAR at 3 months postoperatively. The mean endothelial cell loss was 145 ± 123 cells/mm2 at 3 months postoperatively. There was no significant difference in postoperative outcomes between both the groups. Conclusion: The technique can be safely applied in all cataracts, especially posterior polar cataract and white mature cataract where hydrodissection is contraindicated.
- Published
- 2021
- Full Text
- View/download PDF
21. Phacocapsulectomy: A novel technique to deal with extensive capsular fibrosis
- Author
-
Narayan Bardoloi and Sandip Sarkar
- Subjects
anterior capsular fibrosis ,phacocapsulectomy ,phacoemulsification ,Ophthalmology ,RE1-994 - Abstract
To describe a new technique of performing capsulotomy with phacoemulsification probe in cataracts with extensive capsular fibrosis. After making two side ports and a 2.2-mm temporal limbal incision, the phaco probe is inserted into the eye. An initial cut is made on the fibrosed anterior capsule with the phacotip. Subsequent cuts are made in the same plane to create a central opening which is of 5–5.5 mm size. This opening is quite stable as it is surrounded by fibrous tissue. Phacoemulsification and intra-ocular lens implantation can be safely done through this opening without damaging the integrity of the capsular opening. We have performed phacocapsulectomy in four such cases. All of them gained best-corrected visual acquity better than 20/40 at 3 months of follow-up. Creating a capsular opening in a cataract with extensive anterior capsular fibrosis is always challenging. Phacocapsulectomy can be a very useful method in dealing such cases.
- Published
- 2021
- Full Text
- View/download PDF
22. Minimizing topical medication in cataract surgery
- Author
-
Sandip Sarkar, Nirupama Kasturi, and Narayan Bardoloi
- Subjects
dropless cataract surgery ,endophthalmitis prophylaxis ,iris dilation ,topical medication ,transzonular ,Ophthalmology ,RE1-994 - Abstract
Cataract surgery requires the use of multiple topical eye drops application in the pre and postoperative period. Certain strategies offer the patient and surgeon assured drug delivery without topical eye drop instillation avoiding the pitfalls of patient drug compliance, incorrect instillation, and topical drop-associated side effects. The aim of the current review is to evaluate the aspects of drop-free cataract surgery starting from intraoperative pupil dilation to intravitreal drug instillation.
- Published
- 2021
- Full Text
- View/download PDF
23. Efficacy and safety of dropless cataract surgery
- Author
-
Narayan Bardoloi, Sandip Sarkar, Ashu Pilania, and Himangshu Das
- Subjects
dropless ,phacoemulsification ,transzonular ,Ophthalmology ,RE1-994 - Abstract
Purpose: To evaluate the clinical outcome following intraoperative transzonular intravitreal injection of triamcinolone acetonide and moxifloxacin in patients undergoing phacoemulsification cataract extraction with intraocular lens (IOL) implantation. Methods: In this prospective, non-randomized, clinical, interventional study, a total of 200 eyes were enrolled. Patients who voluntarily gave their consent after being informed about dropless cataract surgery along with its pros and cons were included. Those who had glaucoma or were known steroid responders as well as those who were lost to follow-up were excluded. 0.1 ml each of moxifloxacin (500 mg) and triamcinolone acetonide (4 mg) were injected transzonularly following IOL implantation in phacoemulsification cataract surgery with the help of 27G curved cannula. Slit-lamp examination was done to detect cells, visual acuity was noted, and intraocular pressure was measured postoperatively on day 1, 7, 30, 60, and 90. Results: Uncorrected visual acuity (UCVA) greater than 6/9 was achieved in 96% of patients at the end of 3 months. The mean IOP was found to be normal in all the cases at every visit. Twenty patients complained of floaters on postoperative day 1 (D1), which decreased to zero after 60 days (D60). None of the patients needed any eye drop during the entire postoperative period. Conclusion: The study demonstrates that this procedure is advantageous and safe.
- Published
- 2020
- Full Text
- View/download PDF
24. A comparative study on wound outcome after non approximation against approximation of subcutaneous layer during emergency caesarean section in patients with abdominal subcutaneous layer > 2 cm
- Author
-
Saumya, Amitava Das, Sandip Sarkar, Chiranjit Ghosh, and Abhinav Shrivastava
- Subjects
subcutaneous fat layer ,wound complications ,Gynecology and obstetrics ,RG1-991 - Abstract
Objective: The objective of this study is to compare the outcome of caesarean section post-op wound in patients after either approximation or after non-approximation of the subcutaneous fat layer. Methodology: 390 women who underwent emergency caesarean section having abdominal fat thickness of more than 2 cm were randomly allocated in two groups of 195 each. The subcutaneous fat layer was approximated in the patients of group A. The condition of wound in each patient was examined on 5th postoperative day and the complications, if any were categorised into wound disruption, seroma, hematoma or infection. Then further postoperative analgesic, antibiotic doses and hospital stay duration were compared among two group patients. Result: Among 195 patients of Group A, only 20 (10.26%) had wound complications whereas in Group B, 55 patients had wound complications (28.21 %). In group A patients, only 2.5 % needed secondary suturing whereas in group B patients, 18.9 % needed secondary suturing. Conclusion: Approximation of the subcutaneous tissues separately significantly reduces wound complications, requirement of secondary suturing along with a significant reduction in the duration of hospital stay.
- Published
- 2020
- Full Text
- View/download PDF
25. COVID-19 and orbital mucormycosis
- Author
-
Sandip Sarkar, Tanmay Gokhale, Sushmita Sana Choudhury, and Amit Kumar Deb
- Subjects
Ophthalmology ,RE1-994 - Published
- 2021
- Full Text
- View/download PDF
26. The surgical simulator–assisted postgraduate ophthalmology residency training during the COVID-19 pandemic
- Author
-
Sandip Sarkar, Tanmay Gokhale, Ninan Jacob, Ajax Jossy, Sangaraju Suneel, and Subashini Kaliaperumal
- Subjects
Ophthalmology ,RE1-994 - Published
- 2021
- Full Text
- View/download PDF
27. Sinus bradycardia following single-day use of timolol eye drops in a healthy young adult - A rare case report
- Author
-
Sandip Sarkar, Pragathi Shankaralingappa, Amit Kumar Deb, Sangaraju Suneel, Subashini Kaliaperumal, Kaviyapriya Natarajan, and Sasikumar Mahalingam
- Subjects
hyphemia ,sinus bradycardia ,timolol ,Ophthalmology ,RE1-994 - Abstract
We report the rare case of timolol-induced sinus bradycardia in an otherwise healthy young individual following just 1 day use of timolol eye drops. A 35-year-old male presented with dispersed hyphema and raised intraocular pressure following blunt trauma in the left eye. He was prescribed timolol eye drops and topical steroids. He presented next day with giddiness, sweating, and heart rate (HR) of 30/min. Electrocardiogram confirmed sinus bradycardia injection atropine 0.5 mg intravenous was given. Timolol was substituted with brimonidine-brinzolamide drops. HR returned to normal of 72/min after 2 days of observation. Our case, therefore, represents an exaggerated response to topical timolol.
- Published
- 2021
- Full Text
- View/download PDF
28. Exudative retinal detachment in COVID-19 - associated rhino-orbital mucormycosis – A rare clinical finding
- Author
-
Sandip Sarkar, Tanmay Gokhale, Subashini Kaliaperumal, Rakesh Singh, R Benazir Begam, and Amit Kumar Deb
- Subjects
covid-19 ,exudative retinal detachment ,orbital mucormycosis ,Ophthalmology ,RE1-994 - Abstract
Rhino-orbital-cerebral mucormycosis is a life-threatening, opportunistic invasive fungal infection. Patients with moderate to severe coronavirus disease 2019 (COVID-19) infection are more vulnerable to it. Varied clinical presentations can be seen in patients with orbital mucormycosis starting from conjunctival chemosis, proptosis, ptosis, restriction of extraocular movements, exposure keratitis, neurotrophic keratitis, and central retinal artery occlusion. Exudative retinal detachment in a patient with orbital mucormycosis is a rare clinical entity. We, hereby, report a case of orbital mucormycosis with exudative retinal detachment in a patient post-COVID-19 infection.
- Published
- 2021
- Full Text
- View/download PDF
29. Bilateral vitreous hemorrhage with branch retinal vein occlusion secondary to hyperhomocysteinemia: A rare case report
- Author
-
Amit Kumar Deb, Nithya Rathinam, Sandip Sarkar, Sangaraju Suneel, MalvikaMani, and Subashini Kaliaperumal
- Subjects
bilateral branch retinal vein occlusion ,hyperhomocysteinemia ,vitreous hemorrhage ,Ophthalmology ,RE1-994 - Abstract
Retinal vascular occlusions are uncommon in young people and require more in-depth investigation into the cause. A high level of circulating homocysteine carries a risk for retinal vaso-occlusive events. We, hereby, report a rare case of hyperhomocysteinemia-related bilateral branch retinal vein occlusion (BRVO). A 27-year-old male presented with sudden painless gross diminution of vision in the left eye (LE) for 10 days. Further assessment revealed inferotemporal BRVO (ITBRVO) in the right eye (RE) with mild vitreous hemorrhage (VH) and dense VH in the LE. Extensive investigations into the cause revealed an elevated level of serum homocysteine. The patient was started on Vitamin B6 and B12 supplementation. RE sectoral panretinal photocoagulation and LE pars plana vitrectomy were done. LE ITBRVO was noted intraoperatively for which endolaser was done. Hyperhomocysteinemia through its prothrombotic properties is an independent modifiable risk factor for vascular thrombotic events. Hence, it should be considered as a differential diagnosis for retinal vascular occlusions to prevent further recurrences and cerebrovascular events, especially in young adults.
- Published
- 2021
- Full Text
- View/download PDF
30. Automated Quality-Controlled Cardiovascular Magnetic Resonance Pericardial Fat Quantification Using a Convolutional Neural Network in the UK Biobank
- Author
-
Andrew Bard, Zahra Raisi-Estabragh, Maddalena Ardissino, Aaron Mark Lee, Francesca Pugliese, Damini Dey, Sandip Sarkar, Patricia B. Munroe, Stefan Neubauer, Nicholas C. Harvey, and Steffen E. Petersen
- Subjects
cardiovascular magnetic resonance ,pericardial fat ,epicardial fat ,obesity ,automated image analysis ,neural network ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
Background: Pericardial adipose tissue (PAT) may represent a novel risk marker for cardiovascular disease. However, absence of rapid radiation-free PAT quantification methods has precluded its examination in large cohorts.Objectives: We developed a fully automated quality-controlled tool for cardiovascular magnetic resonance (CMR) PAT quantification in the UK Biobank (UKB).Methods: Image analysis comprised contouring an en-bloc PAT area on four-chamber cine images. We created a ground truth manual analysis dataset randomly split into training and test sets. We built a neural network for automated segmentation using a Multi-residual U-net architecture with incorporation of permanently active dropout layers to facilitate quality control of the model's output using Monte Carlo sampling. We developed an in-built quality control feature, which presents predicted Dice scores. We evaluated model performance against the test set (n = 87), the whole UKB Imaging cohort (n = 45,519), and an external dataset (n = 103). In an independent dataset, we compared automated CMR and cardiac computed tomography (CCT) PAT quantification. Finally, we tested association of CMR PAT with diabetes in the UKB (n = 42,928).Results: Agreement between automated and manual segmentations in the test set was almost identical to inter-observer variability (mean Dice score = 0.8). The quality control method predicted individual Dice scores with Pearson r = 0.75. Model performance remained high in the whole UKB Imaging cohort and in the external dataset, with medium–good quality segmentation in 94.3% (mean Dice score = 0.77) and 94.4% (mean Dice score = 0.78), respectively. There was high correlation between CMR and CCT PAT measures (Pearson r = 0.72, p-value 5.3 ×10−18). Larger CMR PAT area was associated with significantly greater odds of diabetes independent of age, sex, and body mass index.Conclusions: We present a novel fully automated method for CMR PAT quantification with good model performance on independent and external datasets, high correlation with reference standard CCT PAT measurement, and expected clinical associations with diabetes.
- Published
- 2021
- Full Text
- View/download PDF
31. Ophthalmological profile of adult thyroid disease in Southern India
- Author
-
Aswanthi Sadesh Kumar, Subashini Kaliaperumal, Sadish Kumar Kamalanathan, and Sandip Sarkar
- Subjects
Ophthalmology ,RE1-994 - Published
- 2022
- Full Text
- View/download PDF
32. Complications and visual outcome of sutureless, scleral fixated intraocular lens in cases with traumatic aphakia
- Author
-
Amit Kumar Deb, Sandip Sarkar, Kaviyapriya Natarajan, Vignesh Elamurgan, Jagadeeswari Jayaseelan, Tanmay Gokhale, and Ninan Jacob
- Subjects
Ophthalmology ,RE1-994 - Abstract
Purpose: The aim of this study is to describe the complications and outcome of sutureless scleral fixated intraocular lens (SFIOL) implantation in traumatic aphakia. Setting: The study was conducted in a tertiary eye care centre in South India. Design: The study involved a retrospective data analysis. Methods: Medical records of cases with traumatic aphakia who had undergone sutureless SFIOL implantation in the last 2 years were included in the study. Data on intraoperative and postoperative complications and visual outcome were collected and analysed. Results: In total, 45 cases were recruited. Mean logarithm of the minimum angle of resolution (logMAR) best-corrected visual acuity (BCVA) improved from preoperative 1.64 ± 0.45 to 0.63 ± 0.36 at last follow-up visit, and the difference was statistically significant ( p
- Published
- 2021
- Full Text
- View/download PDF
33. P.44 Application of an Algorithm Developed for Measuring Gastrointestinal Motility to the Assessment of Arterial Mechanical Properties
- Author
-
Andrew Bard, Stephen Greenwald, and Sandip Sarkar
- Subjects
MRI ,post-processing ,motion_extraction ,abdominal_aorta ,Specialties of internal medicine ,RC581-951 ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
Background: GIQuant (Motilent, London) is an algorithm for analysing cine-MRI, using the displacement fields generated by registration of indivisdual ciné frames. It produces a summary of how much movement occurs (“motility”) for anatomical locations within a reference image [1]. Although it is used clinically for quantifying gut motility [2], it can process any ciné-MRI. In this study, we explore the hypothesis that it can be used to examine the functionality of blood vessels. Methods: Using ciné-MRI of the abdomen, obtained in initially to assess small-bowel motility in patients with Crohn’s disease, we tested the feasibility of using GIQuant to examine the mechanical properties of blood vessels. In such data, coronal slices often intersect the abdominal aorta and the common iliac arteries. The reference images were manually segmented (see Figure 1A) for statistical analysis of the motility scores. Figure 1A. Example reference image, with abdominal aorta and common iliacs false-coloured according to GlQuant motility score. B-C. Scatter plots showing mean motility scores for both common iliacs (B) and comparisons with aorta (C). D. Scatter plot showing pixelwise motility scores against craniocaudal position, for the image shown in (a) E. r- values from n=25 subjects treated as per (D). Results: We compared the mean motility score in the common iliac arteries, finding that the inter-subject, is greater than the intra-subject variability (Figure 1B). Additionally, motility in the right and left common iliacs is not correlated with that of the abdominal aorta (Figure 1C). When assessed spatially along the abdominal aorta, the motility score is correlated with position in a physiologically plausible manner, showing a general decrease in the caudal direction (Figure 1D–1E). Conclusions: It appears that GIQuant can be used to provide biologically meaningful information about blood vessel properties. Further validation work will use this technique to examine function in patients with bicuspid aortic valves, and to examine its predictive value for aortic aneurysm prognosis.
- Published
- 2020
- Full Text
- View/download PDF
34. Comment on: Intravitreal anti-vascular endothelial growth factor with and without topical non-steroidal anti-inflammatory in centre-involving diabetic macular edema
- Author
-
Sandip Sarkar and Amit Kumar Deb
- Subjects
Ophthalmology ,RE1-994 - Published
- 2022
- Full Text
- View/download PDF
35. Comment on: Anterior chamber intraocular lens - An effective alternative in traumatic and surgical aphakia in the era of scleral-fixated intraocular lens
- Author
-
Sandip Sarkar and Nirupama Kasturi
- Subjects
Ophthalmology ,RE1-994 - Published
- 2022
- Full Text
- View/download PDF
36. Pregnancy outcome in women with congenital heart disease in a tertiary care centre
- Author
-
Lipika Adhikari, Sandip Sarkar, Amitava Das, Priyanka Sannigrahi, and Prateek Chawdhary
- Subjects
congenital heart disease ,arrhythmia ,congestive cardiac failure ,cyanotic heart disease ,Gynecology and obstetrics ,RG1-991 - Abstract
Objective: To find out prevalence of congenital heart disease in pregnant women and its cardiac, obstetric and neonatal outcome. Methodology: A prospective study was conducted on 74 mothers who had congenital heart disease and admitted in Obstetrics and Gynaecology department during a period of December 2013 to December 2017. Baseline data were collected before pregnancy or at the first antenatal visit. These included clinical presentation, ECG, chest X ray, echodoppler study and subsequently maternal cardiac event, obstetric outcome, neonatal event and risk stratification of bad obstetric outcome. Result: During the study period 74 women having congenital heart disease (CHD) were seen. The prevalence of congenital heart disease was 0.14%. Most of the patients had atrial septal defect (ASD) (35%). Normal delivery was in 18 numbers of patients and most of these were ASD and pulmonary stenosis. Large number of patients had developed complication of sustained arrhythmia (41%). Pulmonary oedema was documented in 8 patients. Seven patients expired during labour and puerperium. Regarding fetal outcome 58% pregnancy had intrauterine growth restriction, 67% had preterm birth and 8% had neonatal death. Conclusion: Maternal and neonatal complication rates are considerably high in pregnant women with congenital heart disease.
- Published
- 2018
- Full Text
- View/download PDF
37. Comments on: Reworking protocols of ophthalmic resident surgical training in the COVID-19 era – Experiences of a tertiary care institute in Northern India
- Author
-
Sandip Sarkar, Nirupama Kasturi, P P Jayasri, and Subashini Kaliaperumal
- Subjects
Ophthalmology ,RE1-994 - Published
- 2021
- Full Text
- View/download PDF
38. Smartphone-assisted retinal evaluation in COVID-19 admitted patients
- Author
-
Sandip Sarkar, Tanmay Gokhale, Y Farnaz, and Amit Kumar Deb
- Subjects
Ophthalmology ,RE1-994 - Published
- 2021
- Full Text
- View/download PDF
39. Significance of Natural Scene Statistics in Understanding the Anisotropies of Perceptual Filling-in at the Blind Spot
- Author
-
Rajani Raman and Sandip Sarkar
- Subjects
Medicine ,Science - Abstract
Abstract Psychophysical experiments reveal our horizontal preference in perceptual filling-in at the blind spot. On the other hand, tolerance in filling-in exhibit vertical preference. What causes this anisotropy in our perception? Building upon the general notion that the functional properties of the early visual system are shaped by the innate specification as well as the statistics of the environment, we reasoned that the anisotropy in filling-in could be understood in terms of anisotropy in orientation distribution inherent in natural scene statistics. We examined this proposition by investigating filling-in of bar stimuli in a Hierarchical Predictive Coding model network. The model network, trained with natural images, exhibited anisotropic filling-in performance at the blind spot, which is similar to the findings of psychophysical experiments. We suggest that the over-representation of horizontal contours in the natural scene contributes to the observed horizontal superiority in filling-in and the broader distribution of vertical contours contributes to the observed vertical superiority of tolerance in filling-in. These results indicate that natural scene statistics plays a significant role in determining the filling-in performance at the blind spot and shaping the associated anisotropies.
- Published
- 2017
- Full Text
- View/download PDF
40. Comment on: Preoperative SARS CoV-2 rapid antigen test and reverse transcription polymerase chain reaction: A conundrum in surgical decision making
- Author
-
Sandip Sarkar, Tanmay Gokhale, Amit Kumar Deb, and Subashini Kaliaperumal
- Subjects
Ophthalmology ,RE1-994 - Published
- 2021
- Full Text
- View/download PDF
41. Predictive Coding: A Possible Explanation of Filling-In at the Blind Spot.
- Author
-
Rajani Raman and Sandip Sarkar
- Subjects
Medicine ,Science - Abstract
Filling-in at the blind spot is a perceptual phenomenon in which the visual system fills the informational void, which arises due to the absence of retinal input corresponding to the optic disc, with surrounding visual attributes. It is known that during filling-in, nonlinear neural responses are observed in the early visual area that correlates with the perception, but the knowledge of underlying neural mechanism for filling-in at the blind spot is far from complete. In this work, we attempted to present a fresh perspective on the computational mechanism of filling-in process in the framework of hierarchical predictive coding, which provides a functional explanation for a range of neural responses in the cortex. We simulated a three-level hierarchical network and observe its response while stimulating the network with different bar stimulus across the blind spot. We find that the predictive-estimator neurons that represent blind spot in primary visual cortex exhibit elevated non-linear response when the bar stimulated both sides of the blind spot. Using generative model, we also show that these responses represent the filling-in completion. All these results are consistent with the finding of psychophysical and physiological studies. In this study, we also demonstrate that the tolerance in filling-in qualitatively matches with the experimental findings related to non-aligned bars. We discuss this phenomenon in the predictive coding paradigm and show that all our results could be explained by taking into account the efficient coding of natural images along with feedback and feed-forward connections that allow priors and predictions to co-evolve to arrive at the best prediction. These results suggest that the filling-in process could be a manifestation of the general computational principle of hierarchical predictive coding of natural images.
- Published
- 2016
- Full Text
- View/download PDF
42. Analysing and Integrating Evolutionary Algorithms towards Optimum Solution
- Author
-
Debdutta Burman, Sandip Sarkar, Anirban Bhar, and Kundu, Sujata
- Subjects
Computational Time Complexity ,Combinatorial Optimization Problems ,Evolutionary Algorithms (EAs) - Abstract
In the theory of evolutionary algorithms (EAs), computational time complexity is an essential problem. This study reports on the average time complexity of EAs. Researchers have been studying the computational time complexity of evolutionary algorithms since the mid-1990s (EAs). The earliest findings were based on toy problems using extremely simple algorithms like the (1+1)-EA. This work resulted in a better knowledge of how EAs perform on various types of fitness landscapes, as well as generic mathematical methods that could be used to analyse increasingly complex EAs on more realistic challenges. In reality, it has been able to study the (1+1)-EA on combinatorial optimization problems with real-world applications, as well as more realistic population-based EAs on structured toy problems in recent years. The results of these two study lines have been surveyed in this report. The most prevalent mathematical procedures are presented, as well as the essential ideas that underpin them and their various applications.
- Published
- 2022
- Full Text
- View/download PDF
43. A new technique of phacoemulsification without hydroprocedures
- Author
-
Sandip Sarkar and Narayan Bardoloi
- Subjects
medicine.medical_specialty ,Visual acuity ,business.industry ,medicine.medical_treatment ,Significant difference ,Mean age ,General Medicine ,Phacoemulsification ,cortical cleavage hydrodissection ,hydroprocedure ,RE1-994 ,Mature cataract ,Posterior polar cataract ,Ophthalmology ,phacoemulsification ,medicine ,chopping ,medicine.symptom ,business ,Capsulorhexis - Abstract
Purpose: We describe a new technique where phacoemulsification can be safely performed without doing hydroprocedure. Materials and Methods: We conducted a prospective, nonrandomized, noncomparative, single-center study where Group A had undergone phacoemulsification without hydroprocedure and Group B had undergone conventional phacoemulsification. After capsulorhexis, we insert the phacoemulsification tip into the eye without doing any hydroprocedure. First shaving of the cortex and epinucleus is done within the capsulorhexis area. Then, the tip is buried into the center of the nucleus and an anteroposterior crack is fashioned. Then, the tip is placed at 8 o'clock position to chop away a piece of nucleus and emulsified. A similar maneuver is done at 4 o'clock position. The phacoemulsification tip and the chopper are now positioned at the cracked site of the lower fragments. Using the two instruments, the fragments are pushed to the opposite direction and emulsified. Results: The mean age of the patients of Group A was 65.7 ± 8.16 years and Group B was 68.9 ± 9.85 years (P = 0.127). The mean best-corrected visual acuity in Group A improved from 0.92 ± 0.49 logarithm of the minimum angle of resolution (logMAR) to 00.01 ± 0.02 logMAR at 3 months postoperatively. The mean endothelial cell loss was 145 ± 123 cells/mm2 at 3 months postoperatively. There was no significant difference in postoperative outcomes between both the groups. Conclusion: The technique can be safely applied in all cataracts, especially posterior polar cataract and white mature cataract where hydrodissection is contraindicated.
- Published
- 2021
44. Phacocapsulectomy: A novel technique to deal with extensive capsular fibrosis
- Author
-
Sandip Sarkar and Narayan Bardoloi
- Subjects
Ophthalmology ,genetic structures ,phacoemulsification ,General Medicine ,anterior capsular fibrosis ,phacocapsulectomy ,RE1-994 ,eye diseases - Abstract
To describe a new technique of performing capsulotomy with phacoemulsification probe in cataracts with extensive capsular fibrosis. After making two side ports and a 2.2-mm temporal limbal incision, the phaco probe is inserted into the eye. An initial cut is made on the fibrosed anterior capsule with the phacotip. Subsequent cuts are made in the same plane to create a central opening which is of 5–5.5 mm size. This opening is quite stable as it is surrounded by fibrous tissue. Phacoemulsification and intra-ocular lens implantation can be safely done through this opening without damaging the integrity of the capsular opening. We have performed phacocapsulectomy in four such cases. All of them gained best-corrected visual acquity better than 20/40 at 3 months of follow-up. Creating a capsular opening in a cataract with extensive anterior capsular fibrosis is always challenging. Phacocapsulectomy can be a very useful method in dealing such cases.
- Published
- 2021
45. Numerical calculation of RPC time resolution
- Author
-
Jaydeep Datta, Nayana Majumdar, Supratik Mukhopadhyay, and Sandip Sarkar
- Subjects
History ,High Energy Physics - Experiment (hep-ex) ,Physics - Instrumentation and Detectors ,Physics::Instrumentation and Detectors ,FOS: Physical sciences ,Instrumentation and Detectors (physics.ins-det) ,Computer Science Applications ,Education ,High Energy Physics - Experiment - Abstract
Resistive Plate Chamber (RPC) is a gaseous detector, known for its good spatial resolution and excellent time resolution. Due to its fast response and excellent time resolution, it is used for both triggering and timing purpose. But the time resolution of RPC is dependent on the detector geometry, applied voltage and the gas mixture used for detector operation. In this work, we have tried to develop a numerical model to estimate the time resolution of the detector. The model is developed using COMSOL Multiphysics, a commercially available finite element method solver. Using the primary ionization information from HEED and the electron transport properties from MAGBOLTZ, the model solves the Boltzmann equations to simulate the avalanche in the detector and finds the time to cross a previously determined threshold current, which is used to measure the time resolution of the detector., Presented at NCFMP 2021. Submitted to Journal of Physics Conference Series as part of the proceedings
- Published
- 2022
46. Efficacy and safety of dropless cataract surgery
- Author
-
Himangshu Das, Sandip Sarkar, Ashu Pilania, and Narayan Bardoloi
- Subjects
Intraocular pressure ,medicine.medical_specialty ,Visual acuity ,Triamcinolone acetonide ,genetic structures ,medicine.medical_treatment ,Glaucoma ,Intraocular lens ,Cataract Extraction ,Cataract ,Postoperative Complications ,lcsh:Ophthalmology ,Ophthalmology ,medicine ,Humans ,Prospective Studies ,Glucocorticoids ,Intraocular Pressure ,dropless ,business.industry ,Phacoemulsification ,Cataract surgery ,medicine.disease ,Cannula ,eye diseases ,transzonular ,Treatment Outcome ,lcsh:RE1-994 ,phacoemulsification ,sense organs ,medicine.symptom ,business ,medicine.drug - Abstract
Purpose: To evaluate the clinical outcome following intraoperative transzonular intravitreal injection of triamcinolone acetonide and moxifloxacin in patients undergoing phacoemulsification cataract extraction with intraocular lens (IOL) implantation. Methods: In this prospective, non-randomized, clinical, interventional study, a total of 200 eyes were enrolled. Patients who voluntarily gave their consent after being informed about dropless cataract surgery along with its pros and cons were included. Those who had glaucoma or were known steroid responders as well as those who were lost to follow-up were excluded. 0.1 ml each of moxifloxacin (500 mg) and triamcinolone acetonide (4 mg) were injected transzonularly following IOL implantation in phacoemulsification cataract surgery with the help of 27G curved cannula. Slit-lamp examination was done to detect cells, visual acuity was noted, and intraocular pressure was measured postoperatively on day 1, 7, 30, 60, and 90. Results: Uncorrected visual acuity (UCVA) greater than 6/9 was achieved in 96% of patients at the end of 3 months. The mean IOP was found to be normal in all the cases at every visit. Twenty patients complained of floaters on postoperative day 1 (D1), which decreased to zero after 60 days (D60). None of the patients needed any eye drop during the entire postoperative period. Conclusion: The study demonstrates that this procedure is advantageous and safe.
- Published
- 2020
47. Gini Decomposition: An Inequality of Opportunity Perspective
- Author
-
Sandip Sarkar
- Subjects
Economics and Econometrics ,Finance - Published
- 2022
- Full Text
- View/download PDF
48. Study of the interactions of sneezing droplets with particulate matter in a polluted environment
- Author
-
Sandip K. Saha, Sandip Sarkar, and Prasenjit Dey
- Subjects
Fluid Flow and Transfer Processes ,Physics ,Particulate, Multiphase, and Granular Flows ,Mechanical Engineering ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,Suspended particles ,Computational Mechanics ,technology, industry, and agriculture ,Atmospheric pollution ,Mechanics ,Particulates ,Condensed Matter Physics ,Polluted environment ,complex mixtures ,eye diseases ,Aerosol ,ARTICLES ,Mechanics of Materials ,Wetting ,Dispersion (chemistry) - Abstract
We have performed a three-dimensional numerical simulation to determine the effect of local atmospheric pollution level on the spreading characteristics of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus through ejected droplets during sneezing and coughing in an open space. Utilizing a finite volume-based numerical method, we have performed computations for various ranges of droplet diameters and sneezing speeds. The interactions between the droplets and the suspended particles are considered by taking both hydrophobic and hydrophilic wettability characteristics into account. Our computational results show that the virus-containing droplets partially affect aerosols during the path of their transmission. With the progression of time, the droplet distribution shows an asymmetric pattern. The maximum dispersion of these droplets is found for higher sneezing velocities. The droplets with a diameter of 50 μm travel a larger distance than the larger diameter droplets. We have found that an aerosol with hydrophilic wettability undergoes complete wetting by the disease-containing droplets and therefore is conducive to disease propagation. The droplet engagement duration with aerosol decreases with increase in the sneezing velocity. Our study recommends against using physical exercise centers in a closed environment such as gymnasium and indoor games during the COVID pandemic, especially in a polluted environment. The results from our work will help in deciding proper social distancing guidelines based on the local atmospheric pollution level. They may act as a precursor in controlling further spread of diseases during this unprecedented situation of the COVID pandemic.
- Published
- 2021
49. Bilateral vitreous hemorrhage with branch retinal vein occlusion secondary to hyperhomocysteinemia: A rare case report
- Author
-
Sandip Sarkar, Nithya Rathinam, MalvikaMani, Sangaraju Suneel, Subashini Kaliaperumal, and Amit Kumar Deb
- Subjects
Pars plana ,Hyperhomocysteinemia ,medicine.medical_specialty ,Homocysteine ,genetic structures ,medicine.medical_treatment ,Vitrectomy ,bilateral branch retinal vein occlusion ,chemistry.chemical_compound ,Ophthalmology ,Medicine ,hyperhomocysteinemia ,Retinal Vascular Occlusion ,vitreous hemorrhage ,business.industry ,Retinal ,General Medicine ,RE1-994 ,medicine.disease ,eye diseases ,medicine.anatomical_structure ,chemistry ,Vitreous hemorrhage ,Branch retinal vein occlusion ,business - Abstract
Retinal vascular occlusions are uncommon in young people and require more in-depth investigation into the cause. A high level of circulating homocysteine carries a risk for retinal vaso-occlusive events. We, hereby, report a rare case of hyperhomocysteinemia-related bilateral branch retinal vein occlusion (BRVO). A 27-year-old male presented with sudden painless gross diminution of vision in the left eye (LE) for 10 days. Further assessment revealed inferotemporal BRVO (ITBRVO) in the right eye (RE) with mild vitreous hemorrhage (VH) and dense VH in the LE. Extensive investigations into the cause revealed an elevated level of serum homocysteine. The patient was started on Vitamin B6 and B12 supplementation. RE sectoral panretinal photocoagulation and LE pars plana vitrectomy were done. LE ITBRVO was noted intraoperatively for which endolaser was done. Hyperhomocysteinemia through its prothrombotic properties is an independent modifiable risk factor for vascular thrombotic events. Hence, it should be considered as a differential diagnosis for retinal vascular occlusions to prevent further recurrences and cerebrovascular events, especially in young adults.
- Published
- 2021
50. COVID-19 and orbital mucormycosis
- Author
-
Sushmita Sana Choudhury, Amit Kumar Deb, Tanmay Gokhale, and Sandip Sarkar
- Subjects
2019-20 coronavirus outbreak ,Coronavirus disease 2019 (COVID-19) ,business.industry ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,Mucormycosis ,medicine.disease ,Virology ,Ophthalmology ,lcsh:Ophthalmology ,lcsh:RE1-994 ,medicine ,Orbital Diseases ,Orbital mucormycosis ,business ,Letters to the Editor - Published
- 2021
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.