9 results on '"Karatzas, Nicolaos"'
Search Results
2. Comparing the Drop Vertical Jump Tracking Performance of the Azure Kinect to the Kinect V2.
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Abdelnour, Patrik, Zhao, Kevin Y., Babouras, Athanasios, Corban, Jason Philip Aaron Hiro, Karatzas, Nicolaos, Fevens, Thomas, and Martineau, Paul Andre
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KINECT (Motion sensor) ,VERTICAL jump ,KNEE ,MOTION capture (Human mechanics) ,INTRACLASS correlation ,ANTERIOR cruciate ligament injuries - Abstract
Traditional motion analysis systems are impractical for widespread screening of non-contact anterior cruciate ligament (ACL) injury risk. The Kinect V2 has been identified as a portable and reliable alternative but was replaced by the Azure Kinect. We hypothesize that the Azure Kinect will assess drop vertical jump (DVJ) parameters associated with ACL injury risk with similar accuracy to its predecessor, the Kinect V2. Sixty-nine participants performed DVJs while being recorded by both the Azure Kinect and the Kinect V2 simultaneously. Our software analyzed the data to identify initial coronal, peak coronal, and peak sagittal knee angles. Agreement between the two systems was evaluated using the intraclass correlation coefficient (ICC). There was poor agreement between the Azure Kinect and the Kinect V2 for initial and peak coronal angles (ICC values ranging from 0.135 to 0.446), and moderate agreement for peak sagittal angles (ICC = 0.608, 0.655 for left and right knees, respectively). At this point in time, the Azure Kinect system is not a reliable successor to the Kinect V2 system for assessment of initial coronal, peak coronal, and peak sagittal angles during a DVJ, despite demonstrating superior tracking of continuous knee angles. Alternative motion analysis systems should be explored. [ABSTRACT FROM AUTHOR]
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- 2024
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3. Extracellular vesicles from genetically unstable, oncogene-driven cancer cells trigger micronuclei formation in endothelial cells
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Chennakrishnaiah, Shilpa, Tsering, Thupten, Gregory, Caroline, Tawil, Nadim, Spinelli, Cristiana, Montermini, Laura, Karatzas, Nicolaos, Aprikian, Saro, Choi, Dongsic, Klewes, Ludger, Mai, Sabine, and Rak, Janusz
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- 2020
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4. Comparing a Portable Motion Analysis System against the Gold Standard for Potential Anterior Cruciate Ligament Injury Prevention and Screening.
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Karatzas, Nicolaos, Abdelnour, Patrik, Aaron Hiro Corban, Jason Philip, Zhao, Kevin Y., Veilleux, Louis-Nicolas, Bergeron, Stephane G., Fevens, Thomas, Rivaz, Hassan, Babouras, Athanasios, and Martineau, Paul A.
- Abstract
Knee kinematics during a drop vertical jump, measured by the Kinect V2 (Microsoft, Redmond, WA, USA), have been shown to be associated with an increased risk of non-contact anterior cruciate ligament injury. The accuracy and reliability of the Microsoft Kinect V2 has yet to be assessed specifically for tracking the coronal and sagittal knee angles of the drop vertical jump. Eleven participants performed three drop vertical jumps that were recorded using both the Kinect V2 and a gold standard motion analysis system (Vicon, Los Angeles, CA, USA). The initial coronal, peak coronal, and peak sagittal angles of the left and right knees were measured by both systems simultaneously. Analysis of the data obtained by the Kinect V2 was performed by our software. The differences in the mean knee angles measured by the Kinect V2 and the Vicon system were non-significant for all parameters except for the peak sagittal angle of the right leg with a difference of 7.74 degrees and a p-value of 0.008. There was excellent agreement between the Kinect V2 and the Vicon system, with intraclass correlation coefficients consistently over 0.75 for all knee angles measured. Visual analysis revealed a moderate frame-to-frame variability for coronal angles measured by the Kinect V2. The Kinect V2 can be used to capture knee coronal and sagittal angles with sufficient accuracy during a drop vertical jump, suggesting that a Kinect-based portable motion analysis system is suitable to screen individuals for the risk of non-contact anterior cruciate ligament injury. [ABSTRACT FROM AUTHOR]
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- 2024
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5. Measures and Metrics for Feasibility of Proof-of-Concept Studies With Human Immunodeficiency Virus Rapid Point-of-Care Technologies: The Evidence and the Framework
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Pant Pai, Nitika, Chiavegatti, Tiago, Vijh, Rohit, Karatzas, Nicolaos, Daher, Jana, Smallwood, Megan, Wong, Tom, and Engel, Nora
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- 2017
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6. Using an Affordable Motion Capture System to Evaluate the Prognostic Value of Drop Vertical Jump Parameters for Noncontact ACL Injury.
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Corban, Jason, Karatzas, Nicolaos, Zhao, Kevin Y., Babouras, Athanasios, Bergeron, Stephane, Fevens, Thomas, Rivaz, Hassan, and Martineau, Paul A.
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KNEE radiography , *SPORTS injuries risk factors , *SPORTS participation , *KNEE joint , *RANGE of motion of joints , *CASE-control method , *RISK assessment , *ANTERIOR cruciate ligament injuries , *DESCRIPTIVE statistics , *ABDUCTION (Kinesiology) , *MOTION capture (Human mechanics) , *JUMPING , *SENSITIVITY & specificity (Statistics) , *RECEIVER operating characteristic curves , *DIGITAL video , *KINEMATICS , *LONGITUDINAL method , *DISEASE risk factors - Abstract
Background: Knee kinematic parameters during a drop vertical jump (DVJ) have been demonstrated to be associated with increased risk of noncontact anterior cruciate ligament (ACL) injury. However, standard motion analysis systems are not practical for routine screening. Affordable and practical motion sensor alternatives exist but require further validation in the context of ACL injury risk assessment. Purpose/Hypothesis: To prospectively study DVJ parameters as predictors of noncontact ACL injury in collegiate athletes using an affordable motion capture system (Kinect; Microsoft). We hypothesized that athletes who sustained noncontact ACL injury would have larger initial and peak contact coronal abduction angles and smaller peak flexion angles at the knee during a DVJ. Study Design: Case-control study; Level of evidence, 3. Methods: 102 participants were prospectively recruited from a collegiate varsity sports program. A total of 101 of the 102 athletes (99%) were followed for an entire season for noncontact ACL injury. Each athlete performed 3 DVJs, and the data were recorded using the motion capture system. Initial coronal, peak coronal, and peak sagittal angles of the knee were identified by our software. Results: Five of the 101 athletes sustained a noncontact ACL injury. Peak coronal angles were significantly greater and peak sagittal flexion angles were significantly smaller in ACL-injured athletes (P =.049, P =.049, respectively). Receiver operating characteristic (ROC) analysis demonstrated an area under the curve of 0.88, 0.92, and 0.90 for initial coronal, peak coronal, and peak sagittal angle, respectively. An initial coronal angle cutoff of 2.96° demonstrated 80% sensitivity and 72% specificity, a peak coronal angle cutoff of 6.16° demonstrated 80% sensitivity and 72% specificity, and a peak sagittal flexion cutoff of 93.82° demonstrated 80% sensitivity and 74% specificity on the study cohort. Conclusion: Increased peak coronal angle and decreased peak sagittal angle during a DVJ were significantly associated with increased risk for noncontact ACL injury. Based on ROC analysis, initial coronal angle showed good prognostic ability, whereas peak coronal angle and peak sagittal flexion provided excellent prognostic ability. Affordable motion capture systems show promise as cost-effective and practical options for large-scale ACL injury risk screening. [ABSTRACT FROM AUTHOR]
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- 2023
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7. Which community-based HIV initiatives are effective in achieving UNAIDS 90-90-90 targets? A systematic review and meta-analysis of evidence (2007-2018).
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Dave, Sailly, Peter, Trevor, Fogarty, Clare, Karatzas, Nicolaos, Belinsky, Nandi, and Pant Pai, Nitika
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META-analysis ,HIV ,THERAPEUTICS ,MULTIVARIABLE testing ,MEDICAL care ,STATISTICAL significance - Abstract
Background: Reaching the Joint United Nations Programme on HIV/AIDS (UNAIDS) 90-90-90 targets to end the HIV epidemic relies on effective interventions that engage untested HIV+ individuals and retain them in care. Evidence on community-based interventions through the lens of the targets has not yet been synthesized, reflecting a knowledge gap. We conducted a systematic review and meta-analysis to shed light on successful community-based interventions that have been effective in contributing, directly or indirectly, towards the UNAIDS 90-90-90 targets: knowledge of HIV status, linkage to care/on treatment, and viral suppression. Linkage to care was also included in this review due to the limitations of studies. Methods: We conducted a systematic review and meta-analysis of the period 2007–2018. Eleven databases were searched to identify community-based interventions designed to improve knowledge of HIV status (in particular HIV testing), linkage to care/on treatment, and/or viral suppression. Eligible studies were classified by intervention, population, country income level, outcomes and success. Success was defined as interventions demonstrating statistical significance between intervention and control group or that reached any target by proportion; 90% testing, 81% linked to care/on treatment and 73% viral suppression. Results: Of 82 eligible studies, 51.2% (42/82) reported on HIV testing (first 90), 20.7% (17/82) on linkage to care/ on treatment (second 90), and 45.1% (37/82) on viral suppression (third 90). In all, 67.1% (55/82) of studies reported success; 21 studies on the first 90, 9 towards linkage to care/on treatment, and 25 towards the third. By strategies, 36.6% deployed community workers/peers, 22% used combined test and treat strategies, 12.2% used educational methods, 8.5% used mobile testing, 7.3% used campaigns and 13.4% used technology. For HIV testing/linkage, combined test/treat interventions were often used, for viral suppression, educational interventions and technologies were commonly deployed. Our pooled analysis suggested that deployment of community health care workers/peer workers significantly improved viral suppression (pooled OR: 1.40 95% CI 1.06–1.86). Of the studies published after 2014, 50.0% reported metrics aligned with UNAIDS targets. Conclusions: Data on linkage to care/on treatment (second target) remained weak, because many studies reported successes on the first and third targets. Stratification by targets and country income levels is informative and guides adaptation of successful interventions in comparable settings. Consistent reporting of clear metrics aligned with UNAIDS targets will aid in synergy of study data with programmatic data that will help reportage. Exploration of innovative interventions, for engagement and linkage and deployment of community/ peer workers is strongly encouraged. [ABSTRACT FROM AUTHOR]
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- 2019
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8. Are policy initiatives aligned to meet UNAIDS 90-90-90 targets impacting HIV testing and linkages to care? Evidence from a systematic review.
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Karatzas, Nicolaos, Peter, Trevor, Dave, Sailly, Fogarty, Clare, Belinsky, Nandi, and Pant Pai, Nitika
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IMPACT testing , *META-analysis , *AIDS , *HIGH-income countries , *MIDDLE-income countries , *MIDDLE class - Abstract
Background: The Joint United Nations Programme on HIV/AIDS (UNAIDS) Fast-Track initiative seeks to eliminate AIDS as a health threat by 2030, with its focus on UNAIDS 90-90-90 targets. Effective policies and programs, if scaled nationally, have the potential to generate a greater impact on HIV control, yet a synthesis of successful HIV policies/programs aligned to the targets is currently unavailable. To fill this gap, we conducted a systematic review to evaluate successful HIV policies and programs to direct future interventions. Methods: For the period 2007–2018, we searched 8 databases and classified eligible studies by country income level, UNAIDS targets, intervention type, and reported outcomes. Study outcomes were classified as per UNAIDS targets; proportionally: 90% target 1, 81% target 2, and 73% target 3. Results: We retrieved 5201 citations and a final set of eight studies on policies. Break up by income: three (38%) from high income, one (12%) from middle income and four (50%) from low income. Break up by outcomes reported: 36% (4/11) focused on HIV testing, 46% (5/11) on antiretroviral therapy initiation, and 18% (2/11) on viral suppression. Across studies, UNAIDS targets were met in high-income countries, where policies and guidelines were adhered to, whereas in low and middle-income countries, non-adherence led to failure to reach the targets. Targets were also met when country infrastructure supported a targeted program and stakeholders were actively engaged. Conclusions: From the studies identified, we deduced a clear, positive correlation between implementation of policies and programs that resulted in an increase in patient awareness and an increase in partner notification with services that encouraged them, and together these resulted in increasing testing rates, and deployment of linkage/retention programs that improved retention in care. An analysis of these studies also suggests that policies, combined with the scale-up incentives, are needed to change the status quo. Incentives to improve the targets must exist; performance incentives at the health care worker level and country level incentives that could transform the nature of care. Given the complexity in reporting of targets, a one size fits all model is not a feasible option. However, the policies created a strong framework to shape future interventions. [ABSTRACT FROM AUTHOR]
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- 2019
- Full Text
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9. Measures and Metrics for Feasibility of Proof-of-Concept Studies With Human Immunodeficiency Virus Rapid Point-of-Care Technologies: The Evidence and the Framework.
- Author
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Pai, Nitika Pant, Chiavegatti, Tiago, Vijh, Rohit, Karatzas, Nicolaos, Daher, Jana, Smallwood, Megan, Wong, Tom, and Engel, Nora
- Published
- 2017
- Full Text
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