222 research outputs found
On the Role of Coupled Damping and Gyroscopic Forces in the Stability and Performance of Mechanical Systems
No full textDamping injection is a well-studied tool in nonlinear control theory to stabilize and shape the transient of mechanical systems. Interestingly, the injection of coupled damping yielding gyroscopic forces has received far less attention. This letter aims to fill this gap for gyroscopic forces that couple actuated and unactuated coordinates. First, we establish sufficient conditions for the stability of the closed loop. Then, we provide analytic results proving that injecting coupled damping may improve the closed-loop performance. We illustrate the results via the stabilization of three mechanical systems.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Learning & Autonomous ControlTeam Azita Dabir
Energy-based shape regulation of soft robots with unactuated dynamics dominated by elasticity
No full textThis paper proposes a model-based control design approach for a broad class of soft robots, having their elastic field dominating gravity in the unactuated coordinates. To this end, we consider finite-dimensional dynamic models obtained from approximations of the system's energy. Then, we propose a general control architecture that can stabilize soft robots based on potential energy shaping. We discuss three specializations of this general architecture: a PD with mixed feedback-feedforward gravity compensation, a PD with feedforward compensation, and a saturated version of the latter. We provide a physical interpretation of the controllers, and we illustrate their applicability through simulations.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Learning & Autonomous ControlTeam Azita Dabir
Differential systemic gene expression profile in patients with diabetic macular edema: Responders versus nonresponders to standard treatment
No full textIntroduction: Diabetic macular edema (DME) is a vision-threatening complication of diabetic retinopathy. The current practice of management is a" trial and error "method of using intravitreal antivascular endothelial growth factor (VEGF)′′ or steroids to treat the patient and watch the response. However, if the patient′s genetic profile helps us choose appropriate medicine, it would help customize treatment option for each patient. This forms the basis of our study. Materials and Methods: A case-control, prospective, observational series, where DME patients were treated with bevacizumab and subclassified as treatment naοve, treatment responders, and treatment nonresponders. Blood samples of 20 subjects were studied, with five patients in each of the groups (nondiabetic- group 1, treatment naοve- group 2, treatment responder- group 3, and treatment nonresponder-group 4). Whole blood RNA extraction followed by labeling, amplification and hybridization was done, and microarray data analyzed. Genes were classified based on functional category and pathways. Results: The total number of genes upregulated among all three experimental groups was 5, whereas 105 genes were downregulated. There were no common genes upregulated between the responders and nonresponders. There was only one gene upregulated between the diabetic and diabetic responders posttreatment. There were 19 genes upregulated and 8 genes downregulated in the inflammatory pathway in group 2 versus group 1. There were no downregulated genes detected in vascular angiogenesis and transcription group. There were identical numbers of genes up- and downregulated in the inflammatory pathway. Seventeen genes were upreguated and 11 genes downregulated in receptor activity, which remained the predominant group in the group classification. Discussion: In summary, this study would provide an insight into the probable signaling mechanisms for disease pathogenesis as well as progression. This type of study eventually would aid in developing or improvising existing treatment modules with a rational approach towards personalized medicine, in future addressing the differential responses to treatment
Deep Learning for Object Detection and Segmentation in Videos: Toward an Integration With Domain Knowledge
No full textDeep learning has enabled the rapid expansion of computer vision tasks from image frames to video segments. This paper focuses on the review of the latest research in the field of computer vision tasks in general and on object localization and identification of their associated pixels in video frames in particular. After performing a systematic analysis of the existing methods, the challenges related to computer vision tasks are presented. In order to address the existing challenges, a hybrid framework is proposed, where deep learning methods are coupled with domain knowledge. An additional feature of this survey is that a review of the currently existing approaches integrating domain knowledge with deep learning techniques is presented. Finally, some conclusions on the implementation of hybrid architectures to perform computer vision tasks are discussed.Team Bart De SchutterTeam Azita Dabir
The “Triangle” Sign: A Novel Ultrasound Marker for Diagnosing Total Choroidal Detachment and Total Suprachoroidal Hemorrhage
No full textVaidehi D Bhatt,1 Deepak C Bhatt,1 Kalpana D Bhatt,1 Supriya Dabir,2 Tos TJM Berendschot,3 Roel J Erckens,3 Carroll AB Webers3 1UBM Institute, Mumbai, India; 2Department of Retina, Rajan Eye Care Pvt Ltd, Chennai, India; 3University Eye Clinic Maastricht, Maastricht, the NetherlandsCorrespondence: Vaidehi D Bhatt, UBM Institute, A/1 Ganesh Baug, Dadar, Mumbai, 400019, India, Tel +91-9821525810, Email [email protected]: This study aims to explore the diagnostic utility of ultrasound B-scan while introducing the “Triangle” sign as a novel indicator. It also validates the sign’s efficacy in distinguishing between choroidal detachment (CD) and suprachoroidal hemorrhage (SCH) from retinal detachment (RD) and vitreous hemorrhage (VH).Patients and Methods: Retrospective analysis of consecutive cases of total CD and SCH undergoing B-scan at a single tertiary imaging center. The study examined the presence of the “Triangle” sign (a hypoechoic/anechoic triangular shape of vitreous noted anterior to the optic disc) in total CD & SCH, categorized cases by subtype and etiology, and its role in differentiating from RD and VH.Results: Thirty-six eyes with a total CD and SCH were analyzed. Amongst the cases of total SCH 31 (86.1%), (58.1%) were linked to intraocular surgery, and (41.9%) were linked to post-traumatic events. The “Triangle” sign was consistently present in all 36 eyes, with additional findings indicating concurrent VH (52.8%) or RD (5.6%). Among the 31 eyes with total SCH, 58.3% initially had detectable choroidal membrane seen on B scan, while 41.7% did not. Despite this, the “Triangle” sign was consistently visible in all 36 eyes, and monitoring with B-scans revealed choroidal membrane as the hemorrhage resolved.Conclusion: The “Triangle” sign is a distinctive and reliable ultrasound feature for total CD and SCH diagnosis, offering clarity in challenging cases where traditional methods face limitations.Keywords: choroidal detachment, suprachoroidal hemorrhage, ultrasound B-sca
Review of Karimi, Simin, Vida Samiian and Donald Stilo (eds.), Aspects of Iranian Linguistics. Newcastle upon Tyne: Cambridge Scholars Publishing, 2008, 440 pp.
No full textDevelopment and Evaluation of a Deep Learning Algorithm to Differentiate Between Membranes Attached to the Optic Disc on Ultrasonography
No full textVaidehi D Bhatt,1 Nikhil Shah,2 Deepak C Bhatt,1 Supriya Dabir,3 Jay Sheth,4 Tos TJM Berendschot,5 Roel J Erckens,5 Carroll AB Webers5 1UBM Institute, Mumbai, India; 2Pursuing Masters in Computer Science at Stevens Institute of Technology, Jersey City, NJ, USA; 3Department of Retina, Rajan Eye Care Pvt Ltd, Chennai, India; 4Shantilal Shanghvi Eye Institute, Mumbai, India; 5University Eye Clinic Maastricht, Maastricht, the NetherlandsCorrespondence: Vaidehi D Bhatt, UBM Institute, A/1 Ganesh Baug, Dadar, Mumbai, 400019, India, Tel +91 9821525810, Email [email protected]: The purpose of this study was to create and test a deep learning algorithm that could identify and distinguish between membranes attached to optic disc [OD; retinal detachment (RD)/posterior vitreous detachment (PVD)] based on ocular ultrasonography (USG).Patients and Methods: We obtained a database of B-scan ultrasonography from a high-volume imaging center. A transformer-based Vision Transformer (ViT) model was employed, pre-trained on ImageNet21K, to classify ultrasound B-scan images into healthy, RD, and PVD. Images were pre-processed using Hugging Face’s AutoImage Processor for standardization. Labels were mapped to numerical values, and the dataset was split into training and validation (505 samples), and testing (212 samples) subsets to evaluate model performance. Alternate methods, such as ensemble strategies and object detection pipelines, were explored but showed limited improvement in classification accuracy.Results: The AI model demonstrated high classification performance, achieving an accuracy of 98.21% for PVD, 97.22% for RD, and 95.83% for normal cases. Sensitivity was 98.21% for PVD, 96.55% for RD, and 92.86% for normal cases, while specificity reached 95.16%, 100%, and 95.42%, respectively. Despite the overall strong performance, some misclassification occurred, with seven instances of RD being incorrectly labeled as PVD.Conclusion: We developed a transformer-based deep learning algorithm for ocular ultrasonography that accurately identifies membranes attached to the optic disc, distinguishing between RD (97.22% accuracy) and PVD (98.21% accuracy). Despite seven misclassifications, our model demonstrates robust performance and enhances diagnostic efficiency in high-volume imaging settings, thereby facilitating timely referrals and ultimately improving patient outcomes in urgent care scenarios. Overall, this promising innovation shows potential for clinical adoption.Keywords: retinal detachment, posterior vitreous detachment, ultrasonography, artificial intelligence, deep learning algorith
Proteasome inhibition stabilizes tau inclusions in oligodendroglial cells that occur after treatment with okadaic acid
No full textTau-positive inclusions in oligodendrocytes are consistent neuropathological features of corticobasal degeneration, progressive supranuclear palsy, and frontotemporal dementias with Parkinsonism linked to chromosome 17. Here we show by immunohistochemistry that tau-positive oligodendroglial inclusion bodies also contain the small heat-shock protein (HSP) αB-crystallin but not H HSP70. To study the molecular mechanisms underlying inclusion body formation, we engineered an oligodendroglia cell line (OLN-t40) to overexpress the longest human tau isoform. Treatment of OLN-t40 cells with okadaic acid (OA), an inhibitor of protein phosphatase 2A, caused tau hyperphosphorylation and a decrease in the binding of tau to microtubules. Simultaneously, tau-positive aggregates that also stained with the amyloid-binding dye thioflavin-S as well as with antibodies to tau and αB-crystallin were detected. However, they were only transiently expressed and were degraded within 24 hr. When the proteasomal apparatus was inhibited by carbobenzoxy-L-leucyl-L-leucyl-L-leucinal (MG-132) after OA treatment, the aggregates were stabilized and were still detectable after 18 hr in the absence of OA. Incubation with MG-132 alone inhibited tau proteolysis and led to the induction of HSPs, including αB-crystallin and to its translocation to the perinuclear region, but did not induce the formation of thioflavin-S-positive aggregates. Hence, although tau hyperphosphorylation induced by protein phosphatase inhibition contributes to pathological aggregate formation, only hyperphosporylation of tau followed by proteasome inhibition leads to stable fibrillary deposits of tau similar to those observed in neurodegenerative diseases
Immunoprophylactic evaluation of a 37-kDa Brugia malayi recombinant antigen in lymphatic filariasis
No full textABSTRACTThe Brugia malayi filarial antigens recognised preferentially by sera from an endemic normal population are considered to be potential vaccine candidates. By immunoscreening the cDNA library of the infective L3 stage of B. malayi with pooled endemic normal sera, a cDNA clone Bm-SL3 was identified. Analysis of sera from different patient groups with the rBm-SL3 protein showed it to be highly reactive with endemic normal sera compared to its reactivity with microfilaraemic and non-endemic normal sera. The immunoprotective efficacy of the rBm-SL3 antigen against B. malayi filarial infection was evaluated in susceptible host jirds (gerbils) (Meriones unguiculatus). Jirds immunised with the rBm-SL3 antigen showed 68% cytotoxicity against microfilariae and 67–69% cytotoxicity against infective larvae in in-vitro antibody-dependent cellular cytotoxicity assays and in-situ micropore chamber methods. Analysis of IgG subclasses against Bm-SL3 revealed a significant increase in IgG1 and IgG2 antibodies in endemic normal sera compared with other groups. Lymphocyte proliferation to Bm-SL3 was significantly higher in the endemic normal group compared with that in clinical and microfilarial carriers (p < 0.001). Significantly enhanced levels of IFN-γ in the culture supernatant of peripheral blood mononuclear cells of endemic normal sera after stimulation with Bm-SL3 suggest that the cellular response in this group may have a Th1 bias
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