1
|
Arun R, Sathish Aravindh M, Venkatesan A, Lakshmanan M. Reservoir computing with logistic map. Phys Rev E 2024; 110:034204. [PMID: 39425356 DOI: 10.1103/physreve.110.034204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 08/01/2024] [Indexed: 10/21/2024]
Abstract
Recent studies on reservoir computing essentially involve a high-dimensional dynamical system as the reservoir, which transforms and stores the input as a higher-dimensional state for temporal and nontemporal data processing. We demonstrate here a method to predict temporal and nontemporal tasks by constructing virtual nodes as constituting a reservoir in reservoir computing using a nonlinear map, namely, the logistic map, and a simple finite trigonometric series. We predict three nonlinear systems, namely, Lorenz, Rössler, and Hindmarsh-Rose, for temporal tasks and a seventh-order polynomial for nontemporal tasks with great accuracy. Also, the prediction is made in the presence of noise and found to closely agree with the target. Remarkably, the logistic map performs well and predicts close to the actual or target values. The low values of the root mean square error confirm the accuracy of this method in terms of efficiency. Our approach removes the necessity of continuous dynamical systems for constructing the reservoir in reservoir computing. Moreover, the accurate prediction for the three different nonlinear systems suggests that this method can be considered a general one and can be applied to predict many systems. Finally, we show that the method also accurately anticipates the time series of the all the three variable of Rössler system for the future (self-prediction).
Collapse
|
2
|
Deshaka S, Sathish Aravindh M, Arun R, Venkatesan A, Lakshmanan M. Realization of logic gates in bi-directionally coupled nonlinear oscillators. CHAOS (WOODBURY, N.Y.) 2024; 34:083131. [PMID: 39177962 DOI: 10.1063/5.0217881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Accepted: 08/06/2024] [Indexed: 08/24/2024]
Abstract
Implementation of logic gates has been investigated in nonlinear dynamical systems from various perspectives over the years. Specifically, logic gates have been implemented in both single nonlinear systems and coupled nonlinear oscillators. The majority of the works in the literature have been done on the evolution of single oscillators into OR/AND or NOR/NAND logic gates. In the present study, we demonstrate the design of logic gates in bi-directionally coupled double-well Duffing oscillators by applying two logic inputs to the drive system alone along with a fixed bias. The nonlinear system, comprising both bi-directional components, exhibits varied logic behaviors within an optimal range of coupling strength. Both attractive and repulsive couplings yield similar and complementary logic behaviors in the first and second oscillators. These couplings play a major role in exhibiting fundamental and universal logic gates in simple nonlinear systems. Under a positive bias, both the first and second oscillators demonstrate OR logic gate for the attractive coupling, while exhibiting OR and NOR logic gates, respectively, for the repulsive coupling. Conversely, under a negative bias, both the first and second oscillators display AND logic gate for the attractive coupling, and AND and NAND logical outputs for the repulsive coupling. Furthermore, we confirm the robustness of the bi-directional oscillators against moderate noise in maintaining the desired logical outputs.
Collapse
|
3
|
Ashokkumar P, Kabilan R, Sathish Aravindh M, Venkatesan A, Lakshmanan M. Harnessing vibrational resonance to identify and enhance input signals. CHAOS (WOODBURY, N.Y.) 2024; 34:013129. [PMID: 38252785 DOI: 10.1063/5.0169195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 12/21/2023] [Indexed: 01/24/2024]
Abstract
We report the occurrence of vibrational resonance and the underlying mechanism in a simple piecewise linear electronic circuit, namely, the Murali-Lakshmanan-Chua circuit, driven by an additional biharmonic signal with widely different frequencies. When the amplitude of the high-frequency force is tuned, the resultant vibrational resonance is used to detect the low-frequency signal and also to enhance it into a high-frequency signal. Further, we also show that even when the low-frequency signal is changed from sine wave to square and sawtooth waves, vibrational resonance can be used to detect and enhance them into high-frequency signals. These behaviors, confirmed by experimental results, are illustrated with appropriate analytical and numerical solutions of the corresponding circuit equations describing the system. Finally, we also verify the signal detection in the above circuit even with the addition of noise.
Collapse
|
4
|
Seo A, Xiao W, Gjyshi O, Court K, Napravnik TC, Venkatesan A, Lynn EJ, Sammouri J, Colbert L, Jhingran A, Joyner MM, Lin LL, Gillison M, Klopp AH. HPV Circulating Cell-Free DNA Kinetics in Cervical Cancer Patients Undergoing Definitive Chemoradiation. Int J Radiat Oncol Biol Phys 2023; 117:S8-S9. [PMID: 37784579 DOI: 10.1016/j.ijrobp.2023.06.218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
PURPOSE/OBJECTIVE(S) The human papilloma virus (HPV) is a significant cause of cervical cancer and viral DNA can be detected in the blood of patients with cervical cancer (cfHPV-DNA). We hypothesized that detecting HPV cfDNA before, during and after chemoradiation (CRT) could provide insights into disease extent, clinical staging, and treatment response. MATERIALS/METHODS Forty-seven patients with cervical cancer were enrolled on this study between 2017 and 2022, either as part of a standard-of-care (SOC) treatment banking protocol (33 patients) or as part of a clinical trial combining a therapeutic HPV vaccine (PDS0101; Immunocerv, 14 patients). Longitudinal plasma samples were collected from each patient as baseline, during week 1, 3 or 5 of CRT. cfHPV-DNA was quantified using droplet digital PCR targeting the HPV E6/E7 oncogenes of 13 high-risk types based on analysis of cervical tumor genotype (AmpFire). Clinical covariates, including FIGO stage, primary tumor size, and treatment response were studied using appropriate statistical tests. RESULTS All 47 patients had detectable HPV cfDNA during CRT with 38 out of 47 having HPV type 16 detected. The median cfDNA at baseline was 24.5 copies/mL, with a range of 0 to 157,638 copies/mL. Of the 35 patients with at least three measurements, 20 (57%) had peak cfDNA counts at week 3, and 30 out of 35 showed a decline in cfDNA counts at week 5 compared to week 3. The proportion of patients who cleared cfDNA (<16 copies/mL) increased with each week of CRT, reaching 75% at week 5. Baseline cfDNA counts were associated with para-aortic nodal involvement (p<0.0001) but not with FIGO stage or gross tumor volume. A greater proportion of patients treated with therapeutic HPV-directed vaccine had clearance of cfDNA counts as compared to those treated with SOC (at week 3, 38% vs 5%, P = 0.02 and week 5, 79% vs 22%, P = 0.0054) CONCLUSION: HPV cfDNA levels change dynamically throughout definitive CRT and peak during the first 3 weeks for the majority of patients. Treatment with a therapeutic HPV vaccine was associated with a more rapid decline in cfHPV DNA. Further analysis of cfDNA kinetics could provide valuable information on the relationship between cfDNA levels, treatment response, and clinical outcomes.
Collapse
|
5
|
Devi VK, Venkatesan A, Bharathi AN, Parvathy G, Kaliammal R, Kumar MK, Sudhahar S. Third Order Nonlinear Optical Properties of Bis (Creatininium 2,4-Dichlorobenzoate) Monohydrate Organic New Single Crystal. J Mol Struct 2023. [DOI: 10.1016/j.molstruc.2022.134115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
|
6
|
Mavragani A, Orellana E, Rawlings K, Rodriguez-Pla M, Venkatesan A. Changes in Glycemic Control Following Use of a Spanish-Language, Culturally Adapted Diabetes Program: Retrospective Study. JMIR Form Res 2022; 6:e40278. [PMID: 36476397 PMCID: PMC9773031 DOI: 10.2196/40278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 07/26/2022] [Accepted: 11/15/2022] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Several barriers to diabetes treatment and care exist, particularly in underserved medical communities. OBJECTIVE This study aimed to evaluate a novel, culturally adapted, Spanish-language mHealth diabetes program for glycemic control. METHODS Professional Spanish translators, linguists, and providers localized the entirety of the Vida Health Diabetes Management Program into a culturally relevant Spanish-language version. The Spanish-language Vida Health Diabetes Management Program was used by 182 (n=119 women) Spanish-speaking adults with diabetes. This app-based program provided access to culturally adapted educational content on diabetes self-management, one-on-one remote counseling and coaching sessions, and on-demand in-app messaging with bilingual (Spanish and English) certified health coaches, registered dietitian nutritionists, and certified diabetes care and education specialists. Hemoglobin A1c (HbA1c) was the primary outcome measure, and a 2-tailed, paired t test was used to evaluate changes in HbA1c before and after program use. To determine the relationship between program engagement and changes in glycemic control, a cluster-robust multiple regression analysis was employed. RESULTS We observed a significant decrease in HbA1c of -1.23 points between baseline (mean 9.65%, SD 1.56%) and follow-up (mean 8.42%, SD 1.44%; P<.001). Additionally, we observed a greater decrease in HbA1c among participants with high program engagement (high engagement: -1.59%, SD 1.97%; low engagement: -0.84%, SD 1.64%; P<.001). CONCLUSIONS This work highlights improvements in glycemic control that were clinically as well as statistically significant among Spanish-preferring adults enrolled in the Vida Health Spanish Diabetes Management Program. Greater improvements in glycemic control were observed among participants with higher program engagement. These results provide needed support for the use of digital health interventions to promote meaningful improvements in glycemic control in a medically underserved community.
Collapse
|
7
|
Venkatesan A, Al-Onazi WA, Elshikh MS, Pham TH, Suganya S, Boobas S, Priyadharsan A. Study of synergistic effect of cobalt and carbon codoped with TiO 2 photocatalyst for visible light induced degradation of phenol. CHEMOSPHERE 2022; 305:135333. [PMID: 35709834 DOI: 10.1016/j.chemosphere.2022.135333] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 05/30/2022] [Accepted: 06/10/2022] [Indexed: 06/15/2023]
Abstract
In this work, we reported synthesis of cobalt and carbon codoped TiO2 (Co-C-TiO2) nanoparticles were prepared using co-precipitation technique. The synthesized catalysts are analyzed by various methods. The powder XRD pattern confirmed that all the samples were polycrystalline of anatase phase and particle size of resultant nanoparticle was reduced correlated with bare TiO2 sample. FTIR measurements exhibit the identification of functional groups present at the surface of TiO2. FESEM micrograph showed that the shape of codoped TiO2 nanoparticles are approximately sphere. The attained energy gap of Co doped and C codoping of TiO2 modifies to a level below the energy gap of TiO2 anatase specifying a high capability to absorb visible light. The recombination rate of photo-induced electrons and holes for Co-C codoped TiO2 nanoparticles is significantly reduced. The synthesized samples are assessed in degradation of phenol by the illumination of visible light. The results confirmed that photocatalytic activity enhanced due to doping and codoping of Co and C. As a result, Co-C codoped TiO2 nanoparticles exhibited a higher visible-light photocatalytic activity in compared with Co-TiO2 and bare TiO2 with the maximum degradation efficiency of 98, 75 and 15%, respectively. And also, the reusability of the catalyst was proved when 95% degradation could be achieved after consecutive batches. It is predictable that this work will provide new insights to increase the visible light active photocatalysts for environmental problems.
Collapse
|
8
|
Venkatesan A, Forster B, Rao P, Miller M, Scahill M. Improvements in Depression Outcomes Following a Digital Cognitive Behavioral Therapy Intervention in a Polychronic Population: Retrospective Study. JMIR Form Res 2022; 6:e38005. [PMID: 35788442 PMCID: PMC9297139 DOI: 10.2196/38005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 05/27/2022] [Accepted: 06/08/2022] [Indexed: 02/06/2023] Open
Abstract
Background Digital mental health interventions have shown promise in reducing barriers to effective care for depression. Depression and related mental disorders are known to be highly comorbid with common chronic physical conditions, such as obesity and type 2 diabetes. While some research has explored the interaction dynamics of treating populations living with both mental and physical disorders, very little is known about such dynamics in digital care. Objective We aimed to examine the effectiveness of a 12-week, therapist-supported, app-based cognitive behavioral therapy program in improving symptoms of depression and anxiety. The studied population included adults with a heavy burden of chronic physical disease, including obesity and type 2 diabetes. Methods A total of 1512 participants with at least moderate depression were enrolled. The treatment cohort consisted of 831 (54.96%) participants who completed a follow-up assessment. The program included structured lessons and tools (ie, exercises and practices) and offered one-on-one weekly video counseling sessions with a licensed therapist for 12 weeks and monthly sessions thereafter. The clinically validated 8-item Patient Health Questionnaire (PHQ-8) and the 7-item Generalized Anxiety Disorder scale (GAD-7) were used to assess depression and anxiety, respectively. Linear mixed-effects modeling was employed to examine changes in depression and anxiety over time. Given correlation among various measures of program usage, a composite variable for depth of usage was used to analyze the correlation between usage and changes in depressive symptoms. Body weight changes from baseline were assessed primarily with digitally connected scales. Results Out of 831 participants in the treatment cohort, 74.5% (n=619) showed a clinically significant reduction in depressive symptom severity after 12 weeks, where follow-up PHQ-8 scores had shifted downward by at least one diagnostic category. In total, 67.5% (n=561) of the participants showed a reliable improvement in PHQ-8 scores as measured by the reliable change index. There was an average reduction of 5.9 (SD 5.2) points (P<.001) between baseline and follow-up. Greater program usage was correlated with greater likelihood of reliable improvement in depressive symptoms (odds ratio 1.3, 95% CI 1.1-1.5; P=.002). An exploratory analysis of body weight changes with a multilevel, mixed-effect model suggested that reliable improvement in depressive symptoms at follow-up was associated with significantly greater weight loss at 9 months (β=–1.11, P=.002). Conclusions The results provide further support that digital interventions can support clinically meaningful improvements in depression. Some form of synergy in treatment of comorbid depression and obesity or diabetes could be studied in future research. The study was limited by postintervention participant attrition as well as the retrospective observational study design.
Collapse
|
9
|
Sanders J, Mok H, Tang C, Hanania A, Venkatesan A, Bruno T, Kudchadker R, Thames H, Frank S. Benchmarking Automatic Segmentation Algorithms Against Human Interobserver Variability of Prostate and Organs at Risk Delineation on Prostate MRI. Int J Radiat Oncol Biol Phys 2021. [DOI: 10.1016/j.ijrobp.2021.07.926] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
10
|
Zimmermann G, Venkatesan A, Rawlings K, Scahill MD. Improved Glycemic Control With a Digital Health Intervention in Adults With Type 2 Diabetes: Retrospective Study. JMIR Diabetes 2021; 6:e28033. [PMID: 34075880 PMCID: PMC8209528 DOI: 10.2196/28033] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/01/2021] [Accepted: 04/15/2021] [Indexed: 02/06/2023] Open
Abstract
Background Traditional lifestyle interventions have shown limited success in improving diabetes-related outcomes. Digital interventions with continuously available support and personalized educational content may offer unique advantages for self-management and glycemic control. Objective In this study, we evaluated changes in glycemic control among participants with type 2 diabetes who enrolled in a digital diabetes management program. Methods The study employed a single-arm, retrospective design. A total of 950 participants with a hemoglobin A1c (HbA1c) baseline value of at least 7.0% enrolled in the Vida Health Diabetes Management Program. The intervention included one-to-one remote sessions with a Vida provider and structured lessons and tools related to diabetes management. HbA1c was the primary outcome measure. Of the 950 participants, 258 (27.2%) had a follow-up HbA1c completed at least 90 days from program start. Paired t tests were used to evaluate changes in HbA1c between baseline and follow-up. Additionally, a cluster-robust multiple regression analysis was employed to evaluate the relationship between high and low program usage and HbA1c change. A repeated measures analysis of variance was used to evaluate the difference in HbA1c as a function of the measurement period (ie, pre-Vida enrollment, baseline, and postenrollment follow-up). Results We observed a significant reduction in HbA1c of –0.81 points between baseline (mean 8.68, SD 1.7) and follow-up (mean 7.88, SD 1.46; t257=7.71; P<.001). Among participants considered high risk (baseline HbA1c≥8), there was an average reduction of –1.44 points between baseline (mean 9.73, SD 1.68) and follow-up (mean 8.29, SD 1.64; t139=9.14; P<.001). Additionally, average follow-up HbA1c (mean 7.82, SD 1.41) was significantly lower than pre-enrollment HbA1c (mean 8.12, SD 1.46; F2, 210=22.90; P<.001) There was also significant effect of program usage on HbA1c change (β=–.60; P<.001) such that high usage was associated with a greater decrease in HbA1c (mean –1.02, SD 1.60) compared to low usage (mean –.61, SD 1.72). Conclusions The present study revealed clinically meaningful improvements in glycemic control among participants enrolled in a digital diabetes management intervention. Higher program usage was associated with greater improvements in HbA1c. The findings of the present study suggest that a digital health intervention may represent an accessible, scalable, and effective solution to diabetes management and improved HbA1c. The study was limited by a nonrandomized, observational design and limited postenrollment follow-up data.
Collapse
|
11
|
Kim J, Venkatesan A, Kim H, Kim Y, Whang D, Kim G. Improved Contact Resistance by a Single Atomic Layer Tunneling Effect in WS 2 /MoTe 2 Heterostructures. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2100102. [PMID: 34105270 PMCID: PMC8188188 DOI: 10.1002/advs.202100102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 02/01/2021] [Indexed: 06/12/2023]
Abstract
Manipulation of Ohmic contacts in 2D transition metal dichalcogenides for enhancing the transport properties and enabling its application as a practical device has been a long-sought goal. In this study, n-type tungsten disulfide (WS2 ) single atomic layer to improve the Ohmic contacts of the p-type molybdenum ditelluride (MoTe2 ) material is covered. The Ohmic properties, based on the lowering of Schottky barrier height (SBH) owing to the tunneling barrier effect of the WS2 monolayer, are found to be unexpectedly excellent at room temperature and even at 100 K. The improved SBH and contact resistances are 3 meV and 1 MΩ µm, respectively. The reduction in SBH and contact resistance is confirmed with temperature-dependent transport measurements. This study further demonstrates the selective carrier transport across the MoTe2 and WS2 layers by modulating the applied gate voltage. This WS2 /MoTe2 heterostructure exhibits excellent gate control over the currents of both channels (n-type and p-type). The on/off ratios for both the electron and hole channels are calculated as 107 and 106 , respectively, indicating good carrier type modulation by the electric field of the gate electrode. The Ohmic contact resistance using the tunneling of the atomic layer can be applied to heterojunction combinations of various materials.
Collapse
|
12
|
Ashokkumar P, Sathish Aravindh M, Venkatesan A, Lakshmanan M. Realization of all logic gates and memory latch in the SC-CNN cell of the simple nonlinear MLC circuit. CHAOS (WOODBURY, N.Y.) 2021; 31:063119. [PMID: 34241282 DOI: 10.1063/5.0046968] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 05/28/2021] [Indexed: 06/13/2023]
Abstract
We investigate the State-Controlled Cellular Neural Network framework of Murali-Lakshmanan-Chua circuit system subjected to two logical signals. By exploiting the attractors generated by this circuit in different regions of phase space, we show that the nonlinear circuit is capable of producing all the logic gates, namely, or, and, nor, nand, Ex-or, and Ex-nor gates, available in digital systems. Further, the circuit system emulates three-input gates and Set-Reset flip-flop logic as well. Moreover, all these logical elements and flip-flop are found to be tolerant to noise. These phenomena are also experimentally demonstrated. Thus, our investigation to realize all logic gates and memory latch in a nonlinear circuit system paves the way to replace or complement the existing technology with a limited number of hardware.
Collapse
|
13
|
Venkatesan A, Krymis H, Scharff J, Waber A. Changes in Perceived Stress Following a 10-Week Digital Mindfulness-Based Stress Reduction Program: Retrospective Study. JMIR Form Res 2021; 5:e25078. [PMID: 34032571 PMCID: PMC8188322 DOI: 10.2196/25078] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 01/26/2021] [Accepted: 04/11/2021] [Indexed: 11/13/2022] Open
Abstract
Background As the need for effective scalable interventions for mental health conditions such as depression, anxiety, and stress has grown, the digital delivery of mindfulness-based stress reduction (MBSR) has gained interest as a promising intervention in this domain. Objective This study aims to evaluate the changes in perceived stress following a 10-week digital MBSR program that combined an app-based digital program with weekly one-on-one remote sessions with a health coach. Methods This study used a retrospective, observational design. A total of 229 participants with moderate-to-high perceived stress scores as assessed by the Perceived Stress Scale (PSS)-10 enrolled in the 10-week Vida Health MBSR program. The program included weekly remote sessions with a certified health coach and digital content based on concepts fundamental to mindfulness practice. The PSS-10 was used to evaluate perceived stress. Of the 229 participants, 131 (57.2%) were considered program completers and provided at least one follow-up PSS-10. A secondary analysis examined the changes in stress scores at 6 months. This analysis was restricted to participants who had been enrolled in the program for at least 6 months (n=121). To account for random and fixed effects, linear mixed effects modeling was used to assess changes in stress scores over time. An intention-to-treat approach was used to evaluate the changes in perceived stress across the entire study cohort, including those who were lost to follow-up. In addition, a reliable change index was computed to evaluate the changes in scores from the baseline. Results The findings revealed a significant positive association between program time and stress reduction (B=−0.365; P<.001) at 12 weeks. We observed an average reduction in stress scores of 3.17 points (95% CI −3.93 to −2.44) by program week 6 and 4.86 points (95% CI −5.86 to −3.85) by program week 12. Overall, 83.2% (109/131) of participants showed a reduction in stress scores by week 12, with 40.5% (53/131) of participants showing reliable improvement at 12 weeks and 47.8% (56/131) of participants showing a shift to a lower stress level category (ie, moderate-to-low stress). The intention-to-treat analysis revealed a significant, although attenuated, reduction in stress scores at 12 weeks (B=−0.23; P<.001). Participants who completed more lessons had an increased likelihood of moving down at least one stress level category (odds ratio 1.512, 95% CI 1.056 to 2.166; P=.02). In assessing medium-term outcomes, among participants who had completed at least 6 months in the program, 48.8% (59/121) of members provided a 6-month assessment. We observed a significant reduction in stress scores at 6 months (t58=10.24; P<.001), with 61% (36/59) of participants showing reliable improvement. Conclusions The findings of this retrospective, observational study suggest that a blended, digital mindfulness-based intervention may support program uptake and meaningful, sustained reduction in stress outcomes.
Collapse
|
14
|
Le Thi HY, Khan MA, Venkatesan A, Watanabe K, Taniguchi T, Kim GH. High-performance ambipolar MoS 2transistor enabled by indium edge contacts. NANOTECHNOLOGY 2021; 32:215701. [PMID: 33556924 DOI: 10.1088/1361-6528/abe438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 02/08/2021] [Indexed: 06/12/2023]
Abstract
The integration of electrical contact into 2D heterostructure is an essential approach to high-quality electronic nano-devices, especially field-effect transistors. However, high contact resistance with transition metal dichalcogenides such as molybdenum disulphide (MoS2)-based devices has been a significant fabrication impediment to their potential applications. Here, we have demonstrated the advantage of 1D indium metal contact with fully encapsulated MoS2within hexagonal boron nitride. The electrical measurements of the device exhibit ambipolar transport with an on/off ratio of102for holes and107for electrons. The device exhibits high field-effect mobility of40.7cm2V-1s-1at liquid nitrogen temperature. Furthermore, we have also analysed the charge-transport mechanism at the interface and have calculated the Schottky barrier height from the temperature-dependent measurement. These results are highly promising for the use of air-sensitive material heterostructure and large-scale design of trending flexible, transparent electronic wearable devices.
Collapse
|
15
|
Ankaiah D, Mitra S, Srivastava D, Sivagnanavelmurugan M, Ayyanna R, Jha N, Venkatesan A. Probiotic characterization of bacterial strains from fermented South Indian tomato pickle and country chicken intestine having antioxidative and antiproliferative activities. J Appl Microbiol 2021; 131:949-963. [PMID: 33404172 DOI: 10.1111/jam.14991] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 12/07/2020] [Accepted: 12/28/2020] [Indexed: 12/31/2022]
Abstract
AIM The present study aims to evaluate the potential antioxidant and antiproliferative properties of probiotic bacterial isolates Weissella cibaria p3B, Bacillus subtilis CS, and Bacillus tequilensis CL, isolated from South Indian fermented tomato pickle (homemade) and gut content of indigenous country chicken. METHODS AND RESULTS The bacterial isolates exhibited antimicrobial activity against food-borne, human pathogenic bacteria, along with better survival under different bile and acidic conditions, hydrophobicity towards several hydrocarbons, and adherence to intestinal epithelial cells (INT-407 cells). Also, the intact cell (IC) mixture of the three species showed better DPPH, ABTS, and Fe2+ chelating activity as compared to the individual IC or cell extract (CE) activity. Among the three bacterial species, W. cibaria p3B revealed maximum antiproliferative activity against HeLa and Caco-2 cancer cells, all of which were nontoxic to INT-407 cells. Apart from being non-hemolytic, the bacterial isolates did not display any necrotic inhibition in HeLa and Caco-2 cells. The cell free supernatant (CFS) of the three bacterial isolates were tested for the production of antimicrobial peptides or bacteriocins. It found that the CFS of bacterial isolates was stable at various temperature, pH and sensitive to proteolytic enzymes confirms protenoius in nature of the antimicrobil peptides or bacteriocins. CONCLUSION The bacterial isolates showed promising antimicrobial, antioxidant as well as antiproliferative activities with better survival ability at different pH and bile concentrations. The three bacterial isolates were able to produce potential antimicrobial peptides or bacteriocins. SIGNIFICANCE AND IMPACT OF THE STUDY These results indicate better compatibility of our bacterial isolates against synthetic drugs to avoid adverse side effects and can be processed as dietary supplements against food and human pathogens. They can also provide antioxidative and antiproliferative benefits to humans and animals.
Collapse
|
16
|
Sanders J, Venkatesan A, Davis J, Kudchadker R, Tang C, Bruno T, Ma J, Frank S. OC-1040: Computer aided brachytherapy: assisting the practice of prostate brachytherapy with machine learning. Radiother Oncol 2020. [DOI: 10.1016/s0167-8140(21)01977-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
17
|
De B, Venkatesan A, Msaouel P, Ghia A, Li J, Yeboa D, Nguyen Q, Bishop A, Jonasch E, Shah A, Campbell M, Wang J, Zurita-Saavedra A, Karam J, Wood C, Matin S, Tannir N, Tang C. Definitive Radiotherapy for Oligoprogressive Metastatic Renal Cell Carcinoma as a Strategy to Defer Systemic Therapy Escalation. Int J Radiat Oncol Biol Phys 2020. [DOI: 10.1016/j.ijrobp.2020.07.450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
18
|
Sanders J, Frank S, Venkatesan A, Bathala T, Tang C, Kudchadker R, Bruno T, Pagel M, Ma J. OC-1034: Parallel imaging compressed sensing for prostate MRI without an endorectal coil: a prospective study. Radiother Oncol 2020. [DOI: 10.1016/s0167-8140(21)01973-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
19
|
Rigaud B, Anderson B, Cazoulat G, Yu Z, Soderberg J, Samuelsson E, Ward C, Svensson S, Taku N, Lofman F, Venkatesan A, Klopp A, Brock K. Automatic Segmentation Using Deep Learning for Online Dose Optimization During Adaptive Radiotherapy of Cervical Cancer. Int J Radiat Oncol Biol Phys 2020. [DOI: 10.1016/j.ijrobp.2020.07.2573] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
20
|
Sathish Aravindh M, Venkatesan A, Lakshmanan M. Route to logical strange nonchaotic attractors with single periodic force and noise. CHAOS (WOODBURY, N.Y.) 2020; 30:093137. [PMID: 33003915 DOI: 10.1063/5.0017725] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 09/04/2020] [Indexed: 06/11/2023]
Abstract
Strange nonchaotic attractors (SNAs) have been identified and studied in the literature exclusively in quasiperiodically driven nonlinear dynamical systems. It is an interesting question to ask whether they can be identified with other types of forcings as well, which still remains an open problem. Here, we show that robust SNAs can be created by a small amount of noise in periodically driven nonlinear dynamical systems by a single force. The robustness of these attractors is tested by perturbing the system with logical signals, leading to the emulation of different logical elements in the SNA regions.
Collapse
|
21
|
Venkatesan A, Rahimi L, Kaur M, Mosunic C. Digital Cognitive Behavior Therapy Intervention for Depression and Anxiety: Retrospective Study. JMIR Ment Health 2020; 7:e21304. [PMID: 32845246 PMCID: PMC7481876 DOI: 10.2196/21304] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 07/20/2020] [Accepted: 07/29/2020] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Digital mental health interventions offer a scalable solution that reduces barriers to seeking care for clinical depression and anxiety. OBJECTIVE We aimed to examine the effectiveness of a 12-week therapist supported, app-based cognitive behavioral therapy program in improving symptoms of depression and anxiety within 9 months. METHODS A total of 323 participants with mild to moderately severe depression or anxiety were enrolled in a 12-week digital cognitive behavior therapy program. The analysis was restricted to participants who provided at least one follow-up assessment after baseline. As a result, 146 participants (45.2%) were included in the analysis-74 (50.7%) participants completed assessments at 3 months, 31 participants (21.2%) completed assessments at 6 months, and 21 participants (14.4%) completed assessments at 9 months. The program included structured lessons and tools (ie, exercises and practices) as well as one-on-one weekly video counseling sessions with a licensed therapist for 12 weeks and monthly check-in sessions for 1 year. The clinically validated Patient Health Questionnaire (PHQ-8) and Generalized Anxiety Disorder Scale (GAD-7) were used to assess depression and anxiety, respectively. Linear mixed-effects modeling was employed to examine changes in depression and anxiety over time. RESULTS We observed a significant positive effect of program time on improvement in depression (β=-0.12, P<.001) and anxiety scores (β=-0.10, P<.001). At the end of the 12-week intervention, we observed an average reduction of 3.76 points (95% CI -4.76 to -2.76) in PHQ-8 scores. Further reductions in depression were seen at program month 6 (4.75-point reduction, 95% CI -6.61 to -2.88) and program month 9 (6.42-point reduction, 95% CI -8.66 to -6.55, P<.001). A similar pattern of improvement emerged for anxiety, with a 3.17-point reduction at the end of the 12-week intervention (95% CI -4.21 to -2.13). These improvements were maintained at program month 6 (4.87-point reduction, 95% CI -6.85 to -2.87) and program month 9 (5.19-point, 95% -6.85 to 4.81). In addition, greater program engagement during the first 12 weeks predicted a greater reduction in depression (β=-0.29, P<.001). CONCLUSIONS The results suggest that digital interventions can support sustained and clinically meaningful improvements in depression and anxiety. Furthermore, it appears that strong initial digital mental health intervention engagement may facilitate this effect. However, the study was limited by postintervention participant attrition as well as the retrospective observational study design.
Collapse
|
22
|
Venkatesan A. Influence of Tannery Effluents on Morphological Characters of Ipomoea pes-caprae (L.) Sweet and Clerodendron inerme (L.) Gaertn. NATURE ENVIRONMENT AND POLLUTION TECHNOLOGY 2020. [DOI: 10.46488/nept.2020.v19i02.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
|
23
|
Silberman JM, Kaur M, Sletteland J, Venkatesan A. Outcomes in a digital weight management intervention with one-on-one health coaching. PLoS One 2020; 15:e0232221. [PMID: 32353035 PMCID: PMC7192477 DOI: 10.1371/journal.pone.0232221] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 04/09/2020] [Indexed: 11/19/2022] Open
Abstract
Background Some guidelines state that in-person weight management interventions are more efficacious than those delivered digitally. However, digital programs are more scalable and accessible. We hypothesized that one-on-one health coaching via app-based video chat would simulate an in-person experience and help achieve outcomes comparable to those of in-person interventions. Methods A 12-month digital weight management intervention was provided to overweight or obese adults recruited from a large technology company. One-on-one health coaching sessions were offered during a 24-week intensive phase as well as subsequent maintenance phase. Focused on sustainable changes in activity and diet, the intervention incorporates SMART goals, in-app food and activity logs, Fitbit integration, as well as optional sleep and stress modules. Self-Determination Theory and the Transtheoretical Model are incorporated to drive behavior change. Multilevel mixed-effects models were used to analyze weight changes retrospectively. Results Six hundred eighty-three participants reported 29,051 weights. At 12 months, mean percent changes in body weight were -7.2% and -7.6% for overweight and obese groups, respectively. A weight change of -5% is commonly targeted for in-person weight management interventions. Observed weight loss exceeded this target by 2.2% (95% CI, 0.7% to 3.8%; P < .01) for the overweight group and 2.6% (95% CI, 1.4% to 3.9%; P < .01) for the obese group. Conclusions Further research is needed with randomization to in-person or digital interventions. Though limited by an observational, retrospective design, preliminary results suggest that some digital weight management programs with one-on-one coaching may achieve outcomes comparable to those of robust, in-person interventions.
Collapse
|
24
|
Rigaud B, Klopp A, Vedam S, Venkatesan A, Taku N, Simon A, Haigron P, de Crevoisier R, Brock KK, Cazoulat G. Deformable image registration for dose mapping between external beam radiotherapy and brachytherapy images of cervical cancer. Phys Med Biol 2019; 64:115023. [PMID: 30913542 DOI: 10.1088/1361-6560/ab1378] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
For locally advanced cervical cancer (LACC), anatomy correspondence with and without BT applicator needs to be quantified to merge the delivered doses of external beam radiation therapy (EBRT) and brachytherapy (BT). This study proposed and evaluated different deformable image registration (DIR) methods for this application. Twenty patients who underwent EBRT and BT for LACC were retrospectively analyzed. Each patient had a pre-BT CT at EBRT boost (without applicator) and a CT and MRI at BT (with applicator). The evaluated DIR methods were the diffeomorphic Demons, commercial intensity and hybrid methods, and three different biomechanical models. The biomechanical models considered different boundary conditions (BCs). The impact of the BT devices insertion on the anatomy was quantified. DIR method performances were quantified using geometric criteria between the original and deformed contours. The BT dose was deformed toward the pre-CT BT by each DIR method. The impact of boundary conditions to drive the biomechanical model was evaluated based on the deformation vector field and dose differences. The GEC-ESTRO guideline dose indices were reported. Large organ displacements, deformations, and volume variations were observed between the pre-BT and BT anatomies. Rigid registration and intensity-based DIR resulted in poor geometric accuracy with mean Dice similarity coefficient (DSC) inferior to 0.57, 0.63, 0.42, 0.32, and 0.43 for the rectum, bladder, vagina, cervix and uterus, respectively. Biomechanical models provided a mean DSC of 0.96 for all the organs. By considering the cervix-uterus as one single structure, biomechanical models provided a mean DSC of 0.88 and 0.94 for the cervix and uterus, respectively. The deformed doses were represented for each DIR method. Caution should be used when performing DIR for this application as standard techniques may have unacceptable results. The biomechanical model with the cervix-uterus as one structure provided the most realistic deformations to propagate the BT dose toward the EBRT boost anatomy.
Collapse
|
25
|
Sathish Aravindh M, Venkatesan A, Lakshmanan M. Strange nonchaotic attractors for computation. Phys Rev E 2018; 97:052212. [PMID: 29906833 DOI: 10.1103/physreve.97.052212] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Indexed: 06/08/2023]
Abstract
We investigate the response of quasiperiodically driven nonlinear systems exhibiting strange nonchaotic attractors (SNAs) to deterministic input signals. We show that if one uses two square waves in an aperiodic manner as input to a quasiperiodically driven double-well Duffing oscillator system, the response of the system can produce logical output controlled by such a forcing. Changing the threshold or biasing of the system changes the output to another logic operation and memory latch. The interplay of nonlinearity and quasiperiodic forcing yields logical behavior, and the emergent outcome of such a system is a logic gate. It is further shown that the logical behaviors persist even for an experimental noise floor. Thus the SNA turns out to be an efficient tool for computation.
Collapse
|