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10 results on '"Nikita, Komarov"'

1. The chemosensory system of the Drosophila larva: an overview of current understanding

Author

Nikita Komarov and Simon G. Sprecher

Subjects
drosophila larva, chemosensation, neural circuits, processing, behaviour, model organisms, Biology (General), QH301-705.5
Abstract

Animals must sense their surroundings and be able to distinguish between relevant and irrelevant cues. An enticing area of research aims to uncover the mechanisms by which animals respond to chemical signals that constitute critical sensory input. In this review, we describe the principles of a model chemosensory system: the Drosophila larva. While distinct in many ways, larval behaviour is reminiscent of the dogmatic goals of life: to reach a stage of reproductive potential. It takes into account a number of distinct and identifiable parameters to ultimately provoke or modulate appropriate behavioural output. In this light, we describe current knowledge of chemosensory anatomy, genetic components, and the processing logic of chemical cues. We outline recent advancements and summarize the hypothesized neural circuits of sensory systems. Furthermore, we note yet-unanswered questions to create a basis for further investigation of molecular and systemic mechanisms of chemosensation in Drosophila and beyond.

Published
2022
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2. Taste sensing and sugar detection mechanisms in Drosophila larval primary taste center

Author

G Larisa Maier, Nikita Komarov, Felix Meyenhofer, Jae Young Kwon, and Simon G Sprecher

Subjects
gustatory system, sensory neuron, Drosophila, taste coding, sugar perception, Medicine, Science, Biology (General), QH301-705.5
Abstract

Despite the small number of gustatory sense neurons, Drosophila larvae are able to sense a wide range of chemicals. Although evidence for taste multimodality has been provided in single neurons, an overview of gustatory responses at the periphery is missing and hereby we explore whole-organ calcium imaging of the external taste center. We find that neurons can be activated by different combinations of taste modalities, including opposite hedonic valence and identify distinct temporal dynamics of response. Although sweet sensing has not been fully characterized so far in the external larval gustatory organ, we recorded responses elicited by sugar. Previous findings established that larval sugar sensing relies on the Gr43a pharyngeal receptor, but the question remains if external neurons contribute to this taste. Here, we postulate that external and internal gustation use distinct and complementary mechanisms in sugar sensing and we identify external sucrose sensing neurons.

Published
2021
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3. Niemann–Pick type C disease as proof‐of‐concept for intelligent biomarker panel selection in neurometabolic disorders

Author

Apostolos, Papandreou, Ivan, Doykov, Justyna, Spiewak, Nikita, Komarov, Stephanie, Habermann, Manju A, Kurian, Philippa B, Mills, Kevin, Mills, Paul, Gissen, and Wendy E, Heywood

Subjects
Male, Developmental Neuroscience, Pediatrics, Perinatology and Child Health, Infant, Newborn, Humans, Female, Niemann-Pick Disease, Type C, Neurology (clinical), Child, Biomarkers
Abstract

Using Niemann-Pick type C disease (NPC) as a paradigm, we aimed to improve biomarker discovery in patients with neurometabolic disorders.Using a multiplexed liquid chromatography tandem mass spectrometry dried bloodspot assay, we developed a selective intelligent biomarker panel to monitor known biomarkers N-palmitoyl-O-phosphocholineserine and 3β,5α,6β-trihydroxy-cholanoyl-glycine as well as compounds predicted to be affected in NPC pathology. We applied this panel to a clinically relevant paediatric patient cohort (n = 75; 35 males, 40 females; mean age 7 years 6 months, range 4 days-19 years 8 months) presenting with neurodevelopmental and/or neurodegenerative pathology, similar to that observed in NPC.The panel had a far superior performance compared with individual biomarkers. Namely, NPC-related established biomarkers used individually had 91% to 97% specificity but the combined panel had 100% specificity. Moreover, multivariate analysis revealed long-chain isoforms of glucosylceramide were elevated and very specific for patients with NPC.Despite advancements in next-generation sequencing and precision medicine, neurological non-enzymatic disorders remain difficult to diagnose and lack robust biomarkers or routine functional testing for genetic variants of unknown significance. Biomarker panels may have better diagnostic accuracy than individual biomarkers in neurometabolic disorders, hence they can facilitate more prompt disease identification and implementation of emerging targeted, disease-specific therapies.Intelligent biomarker panel design can help expedite diagnosis in neurometabolic disorders. In Niemann-Pick type C disease, such a panel performed better than individual biomarkers. Biomarker panels are easy to implement and widely applicable to neurometabolic conditions.

Published
2022

5. The chemosensory system of the

Author

Nikita, Komarov and Simon G, Sprecher

Subjects
Larva, Animals, Drosophila, Drosophila larva, chemosensation, processing, Review, neural circuits, behaviour, model organisms
Abstract

Animals must sense their surroundings and be able to distinguish between relevant and irrelevant cues. An enticing area of research aims to uncover the mechanisms by which animals respond to chemical signals that constitute critical sensory input. In this review, we describe the principles of a model chemosensory system: the Drosophila larva. While distinct in many ways, larval behaviour is reminiscent of the dogmatic goals of life: to reach a stage of reproductive potential. It takes into account a number of distinct and identifiable parameters to ultimately provoke or modulate appropriate behavioural output. In this light, we describe current knowledge of chemosensory anatomy, genetic components, and the processing logic of chemical cues. We outline recent advancements and summarize the hypothesized neural circuits of sensory systems. Furthermore, we note yet-unanswered questions to create a basis for further investigation of molecular and systemic mechanisms of chemosensation in Drosophila and beyond.

Published
2021

6. Clinical outcomes of COVID-19 in long-term care facilities for people with epilepsy

Author

Simona Balestrini, Matthias J. Koepp, Sonia Gandhi, Hannah M. Rickman, Gee Yen Shin, Catherine F. Houlihan, Jonny Anders-Cannon, Katri Silvennoinen, Fenglai Xiao, Sara Zagaglia, Kirsty Hudgell, Mariusz Ziomek, Paul Haimes, Adam Sampson, Annie Parker, J. Helen Cross, Rosemarie Pardington, Eleni Nastouli, Charles Swanton, Josemir W. Sander, Sanjay M. Sisodiya, Jim Aitken, Zoe Allen, Rachel Ambler, Karen Ambrose, Emma Ashton, Alida Avola, Samutheswari Balakrishnan, Caitlin Barns-Jenkins, Genevieve Barr, Sam Barrell, Souradeep Basu, Rupert Beale, Clare Beesley, Nisha Bhardwaj, Shahnaz Bibi, Ganka Bineva-Todd, Dhruva Biswas, Michael J. Blackman, Dominique Bonnet, Faye Bowker, Malgorzata Broncel, Claire Brooks, Michael D. Buck, Andrew Buckton, Timothy Budd, Alana Burrell, Louise Busby, Claudio Bussi, Simon Butterworth, Matthew Byott, Fiona Byrne, Richard Byrne, Simon Caidan, Joanna Campbell, Johnathan Canton, Ana Cardoso, Nick Carter, Luiz Carvalho, Raffaella Carzaniga, Natalie Chandler, Qu Chen, Peter Cherepanov, Laura Churchward, Graham Clark, Bobbi Clayton, Clementina Cobolli Gigli, Zena Collins, Sally Cottrell, Margaret Crawford, Laura Cubitt, Tom Cullup, Heledd Davies, Patrick Davis, Dara Davison, Vicky Dearing, Solene Debaisieux, Monica Diaz-Romero, Alison Dibbs, Jessica Diring, Paul C. Driscoll, Annalisa D'Avola, Christopher Earl, Amelia Edwards, Chris Ekin, Dimitrios Evangelopoulos, Rupert Faraway, Antony Fearns, Aaron Ferron, Efthymios Fidanis, Dan Fitz, James Fleming, Daniel Frampton, Bruno Frederico, Alessandra Gaiba, Anthony Gait, Steve Gamblin, Kathleen Gärtner, Liam Gaul, Helen M. Golding, Jacki Goldman, Robert Goldstone, Belen Gomez Dominguez, Hui Gong, Paul R. Grant, Maria Greco, Mariana Grobler, Anabel Guedan, Maximiliano G. Gutierrez, Fiona Hackett, Ross Hall, Steinar Halldorsson, Suzanne Harris, Sugera Hashim, Emine Hatipoglu, Lyn Healy, Judith Heaney, Susanne Herbst, Graeme Hewitt, Theresa Higgins, Steve Hindmarsh, Rajnika Hirani, Joshua Hope, Elizabeth Horton, Beth Hoskins, Michael Howell, Louise Howitt, Jacqueline Hoyle, Mint R. Htun, Michael Hubank, Hector Huerga Encabo, Deborah Hughes, Jane Hughes, Almaz Huseynova, Ming-Shih Hwang, Rachael Instrell, Deborah Jackson, Mariam Jamal-Hanjani, Lucy Jenkins, Ming Jiang, Mark Johnson, Leigh Jones, Nnennaya Kanu, George Kassiotis, Gavin Kelly, Louise Kiely, Anastacio King Spert Teixeira, Stuart Kirk, Svend Kjaer, Ellen Knuepfer, Nikita Komarov, Paul Kotzampaltiris, Konstantinos Kousis, Tammy Krylova, Ania Kucharska, Robyn Labrum, Catherine Lambe, Michelle Lappin, Stacey-Ann Lee, Andrew Levett, Lisa Levett, Marcel Levi, Hon Wing Liu, Sam Loughlin, Wei-Ting Lu, James I. MacRae, Akshay Madoo, Julie A. Marczak, Mimmi Martensson, Thomas Martinez, Bishara Marzook, John Matthews, Joachim M. Matz, Samuel McCall, Laura E. McCoy, Fiona McKay, Edel C. McNamara, Carlos M. Minutti, Gita Mistry, Miriam Molina-Arcas, Beatriz Montaner, Kylie Montgomery, Catherine Moore, David Moore, Anastasia Moraiti, Lucia Moreira-Teixeira, Joyita Mukherjee, Cristina Naceur-Lombardelli, Aileen Nelson, Jerome Nicod, Luke Nightingale, Stephanie Nofal, Paul Nurse, Savita Nutan, Caroline Oedekoven, Anne O'Garra, Jean D. O'Leary, Jessica Olsen, Olga O'Neill, Nicola O'Reilly, Paula Ordonez Suarez, Neil Osborne, Amar Pabari, Aleksandra Pajak, Venizelos Papayannopoulos, Stavroula M Paraskevopoulou, Namita Patel, Yogen Patel, Oana Paun, Nigel Peat, Laura Peces-Barba Castano, Ana Perez Caballero, Jimena Perez-Lloret, Magali S. Perrault, Abigail Perrin, Roy Poh, Enzo Z. Poirier, James M. Polke, Marc Pollitt, Lucia Prieto-Godino, Alize Proust, Clinda Puvirajasinghe, Christophe Queval, Vijaya Ramachandran, Abhinay Ramaprasad, Peter Ratcliffe, Laura Reed, Caetano Reis e Sousa, Kayleigh Richardson, Sophie Ridewood, Fiona Roberts, Rowenna Roberts, Angela Rodgers, Pablo Romero Clavijo, Annachiara Rosa, Alice Rossi, Chloe Roustan, Andrew Rowan, Erik Sahai, Aaron Sait, Katarzyna Sala, Emilie Sanchez, Theo Sanderson, Pierre Santucci, Fatima Sardar, Adam Sateriale, Jill A. Saunders, Chelsea Sawyer, Anja Schlott, Edina Schweighoffer, Sandra Segura-Bayona, Rajvee Shah Punatar, Maryam Shahmanesh, Joe Shaw, Mariana Silva Dos Santos, Margaux Silvestre, Matthew Singer, Daniel M. Snell, Ok-Ryul Song, Moira J. Spyer, Louisa Steel, Amy Strange, Adrienne E. Sullivan, Michele S.Y. Tan, Zoe H. Tautz-Davis, Effie Taylor, Gunes Taylor, Harriet B. Taylor, Alison Taylor-Beadling, Fernanda Teixeira Subtil, Berta Terré Torras, Patrick Toolan-Kerr, Francesca Torelli, Tea Toteva, Moritz Treeck, Hadija Trojer, Ming-Han C. Tsai, James M.A. Turner, Melanie Turner, Jernej Ule, Rachel Ulferts, Sharon P. Vanloo, Selvaraju Veeriah, Subramanian Venkatesan, Karen Vousden, Andreas Wack, Claire Walder, Philip A. Walker, Yiran Wang, Sophia Ward, Catharina Wenman, Luke Williams, Matthew J. Williams, Wai Keong Wong, Joshua Wright, Mary Wu, Lauren Wynne, Zheng Xiang, Melvyn Yap, Julian A. Zagalak, Davide Zecchin, Rachel Zillwood, Santhakumari Carthiyaniamma, Jane DeTisi, Julie Dick, Andrea Hill, Karin Kipper, Birinder Kullar, Sarah Norris, Fergus Rugg-Gunn, Rebecca Salvatierra, Gabriel Shaya, Astrid Sloan, Priyanka Singh, James Varley, Ben Whatley, and Academic Medical Center

Subjects
Male, Pediatrics, CCC, Crick COVID Consortium, SWGC, Sir William Gowers Centre, Comorbidity, Residential Facilities, Cohort Studies, Behavioral Neuroscience, Epilepsy, 0302 clinical medicine, Case fatality rate, Infection control, 030212 general & internal medicine, Care Models, COVID-19, coronavirus disease 2019, Aged, 80 and over, Surveillance, Middle Aged, 3. Good health, Treatment Outcome, Neurology, UCLH, University College London Hospitals NHS Foundation Trust, PEG, percutaneous endoscopic gastrostomy, STE, St Elizabeth’s Centre, Female, medicine.symptom, PPE, personal protective equipment, Cohort study, Adult, medicine.medical_specialty, Isolation (health care), Clinical Neurology, Asymptomatic, Article, Young Adult, 03 medical and health sciences, medicine, Humans, YE, Young Epilepsy, Aged, SARS-CoV-2, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), Infection Control, business.industry, SARS-CoV-2, Prevention, Vulnerable people, COVID-19, TM, The Meath, medicine.disease, Long-Term Care, CCE, Chalfont Centre for Epilepsy, United Kingdom, Long-term care, Neurology (clinical), business, 030217 neurology & neurosurgery, Contact tracing
Abstract

Highlights • We found a high asymptomatic rate in vulnerable people with epilepsy. • Enhanced surveillance allows to quickly contain outbreaks. • We report a low rate of COVID-19 morbidity and mortality in a long-term care facility. • Preventative measures allow reducing resident-to-resident and -to-caregiver transmission. • Children and young adults appear to have lower infection rates., In this cohort study, we aim to compare outcomes from coronavirus disease 2019 (COVID-19) in people with severe epilepsy and other co-morbidities living in long-term care facilities which all implemented early preventative measures, but different levels of surveillance. During 25-week observation period (16 March–6 September 2020), we included 404 residents (118 children), and 1643 caregivers. We compare strategies for infection prevention, control, and containment, and related outcomes, across four UK long-term care facilities. Strategies included early on-site enhancement of preventative and infection control measures, early identification and isolation of symptomatic cases, contact tracing, mass surveillance of asymptomatic cases and contacts. We measured infection rate among vulnerable people living in the facilities and their caregivers, with asymptomatic and symptomatic cases, including fatality rate. We report 38 individuals (17 residents) who tested severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-positive, with outbreaks amongst residents in two facilities. At Chalfont Centre for Epilepsy (CCE), 10/98 residents tested positive: two symptomatic (one died), eight asymptomatic on weekly enhanced surveillance; 2/275 caregivers tested positive: one symptomatic, one asymptomatic. At St Elizabeth’s (STE), 7/146 residents tested positive: four symptomatic (one died), one positive during hospital admission for symptoms unrelated to COVID-19, two asymptomatic on one-off testing of all 146 residents; 106/601 symptomatic caregivers were tested, 13 positive. In addition, during two cycles of systematically testing all asymptomatic carers, four tested positive. At The Meath (TM), 8/80 residents were symptomatic but none tested; 26/250 caregivers were tested, two positive. At Young Epilepsy (YE), 8/80 children were tested, all negative; 22/517 caregivers were tested, one positive. Infection outbreaks in long-term care facilities for vulnerable people with epilepsy can be quickly contained, but only if asymptomatic individuals are identified through enhanced surveillance at resident and caregiver level. We observed a low rate of morbidity and mortality, which confirmed that preventative measures with isolation of suspected and confirmed COVID-19 residents can reduce resident-to-resident and resident-to-caregiver transmission. Children and young adults appear to have lower infection rates. Even in people with epilepsy and multiple co-morbidities, we observed a high percentage of asymptomatic people suggesting that epilepsy-related factors (anti-seizure medications and seizures) do not necessarily lead to poor outcomes.

Published
2021

7. Pandemic peak SARS-CoV-2 infection and seroconversion rates in London frontline health-care workers

Author

Catherine F Houlihan, Nina Vora, Thomas Byrne, Dan Lewer, Gavin Kelly, Judith Heaney, Sonia Gandhi, Moira J Spyer, Rupert Beale, Peter Cherepanov, David Moore, Richard Gilson, Steve Gamblin, George Kassiotis, Laura E McCoy, Charles Swanton, Andrew Hayward, Eleni Nastouli, Jim Aitken, Zoe Allen, Rachel Ambler, Karen Ambrose, Emma Ashton, Alida Avola, Samutheswari Balakrishnan, Caitlin Barns-Jenkins, Genevieve Barr, Sam Barrell, Souradeep Basu, Clare Beesley, Nisha Bhardwaj, Shahnaz Bibi, Ganka Bineva-Todd, Dhruva Biswas, Michael J Blackman, Dominique Bonnet, Faye Bowker, Malgorzata Broncel, Claire Brooks, Michael D Buck, Andrew Buckton, Timothy Budd, Alana Burrell, Louise Busby, Claudio Bussi, Simon Butterworth, Fiona Byrne, Richard Byrne, Simon Caidan, Joanna Campbell, Johnathan Canton, Ana Cardoso, Nick Carter, Luiz Carvalho, Raffaella Carzaniga, Natalie Chandler, Qu Chen, Laura Churchward, Graham Clark, Bobbi Clayton, Clementina Cobolli Gigli, Zena Collins, Sally Cottrell, Margaret Crawford, Laura Cubitt, Tom Cullup, Heledd Davies, Patrick Davis, Dara Davison, Annalisa D'Avola, Vicky Dearing, Solene Debaisieux, Monica Diaz-Romero, Alison Dibbs, Jessica Diring, Paul C Driscoll, Christopher Earl, Amelia Edwards, Chris Ekin, Dimitrios Evangelopoulos, Rupert Faraway, Antony Fearns, Aaron Ferron, Efthymios Fidanis, Dan Fitz, James Fleming, Bruno Frederico, Alessandra Gaiba, Anthony Gait, Liam Gaul, Helen M Golding, Jacki Goldman, Robert Goldstone, Belen Gomez Dominguez, Hui Gong, Paul R Grant, Maria Greco, Mariana Grobler, Anabel Guedan, Maximiliano G Gutierrez, Fiona Hackett, Ross Hall, Steinar Halldorsson, Suzanne Harris, Sugera Hashim, Lyn Healy, Susanne Herbst, Graeme Hewitt, Theresa Higgins, Steve Hindmarsh, Rajnika Hirani, Joshua Hope, Elizabeth Horton, Beth Hoskins, Michael Howell, Louise Howitt, Jacqueline Hoyle, Mint R Htun, Michael Hubank, Hector Huerga Encabo, Deborah Hughes, Jane Hughes, Almaz Huseynova, Ming-Shih Hwang, Rachael Instrell, Deborah Jackson, Mariam Jamal-Hanjani, Lucy Jenkins, Ming Jiang, Mark Johnson, Leigh Jones, Nnennaya Kanu, Louise Kiely, Anastacio King Spert Teixeira, Stuart Kirk, Svend Kjaer, Ellen Knuepfer, Nikita Komarov, Paul Kotzampaltiris, Konstantinos Kousis, Tammy Krylova, Ania Kucharska, Robyn Labrum, Catherine Lambe, Michelle Lappin, Stacey-Ann Lee, Andrew Levett, Lisa Levett, Marcel Levi, Hon-Wing Liu, Sam Loughlin, Wei-Ting Lu, James I MacRae, Akshay Madoo, Julie A Marczak, Mimmi Martensson, Thomas Martinez, Bishara Marzook, John Matthews, Joachim M Matz, Samuel McCall, Fiona McKay, Edel C McNamara, Carlos M Minutti, Gita Mistry, Miriam Molina-Arcas, Beatriz Montaner, Kylie Montgomery, Catherine Moore, Anastasia Moraiti, Lucia Moreira-Teixeira, Joyita Mukherjee, Cristina Naceur-Lombardelli, Aileen Nelson, Jerome Nicod, Luke Nightingale, Stephanie Nofal, Paul Nurse, Savita Nutan, Caroline Oedekoven, Anne O'Garra, Jean D O'Leary, Jessica Olsen, Olga O'Neill, Paula Ordonez Suarez, Nicola O'Reilly, Neil Osborne, Amar Pabari, Aleksandra Pajak, Venizelos Papayannopoulos, Namita Patel, Yogen Patel, Oana Paun, Nigel Peat, Laura Peces-Barba Castano, Ana Perez Caballero, Jimena Perez-Lloret, Magali S Perrault, Abigail Perrin, Roy Poh, Enzo Z Poirier, James M Polke, Marc Pollitt, Lucia Prieto-Godino, Alize Proust, Rajvee Shah Punatar, Clinda Puvirajasinghe, Christophe Queval, Vijaya Ramachandran, Abhinay Ramaprasad, Peter Ratcliffe, Laura Reed, Caetano Reis e Sousa, Kayleigh Richardson, Sophie Ridewood, Rowenna Roberts, Angela Rodgers, Pablo Romero Clavijo, Annachiara Rosa, Alice Rossi, Chloe Roustan, Andrew Rowan, Erik Sahai, Aaron Sait, Katarzyna Sala, Theo Sanderson, Pierre Santucci, Fatima Sardar, Adam Sateriale, Jill A Saunders, Chelsea Sawyer, Anja Schlott, Edina Schweighoffer, Sandra Segura-Bayona, Joe Shaw, Gee Yen Shin, Mariana Silva Dos Santos, Margaux Silvestre, Matthew Singer, Daniel M Snell, Ok-Ryul Song, Louisa Steel, Amy Strange, Adrienne E Sullivan, Michele SY Tan, Zoe H Tautz-Davis, Effie Taylor, Gunes Taylor, Harriet B Taylor, Alison Taylor-Beadling, Fernanda Teixeira Subtil, Berta Terré Torras, Patrick Toolan-Kerr, Francesca Torelli, Tea Toteva, Moritz Treeck, Hadija Trojer, Ming-Han C Tsai, James MA Turner, Melanie Turner, Jernej Ule, Rachel Ulferts, Sharon P Vanloo, Selvaraju Veeriah, Subramanian Venkatesan, Karen Vousden, Andreas Wack, Claire Walder, Philip A Walker, Yiran Wang, Sophia Ward, Catharina Wenman, Luke Wiliams, Matthew J Williams, Wai Keong Wong, Joshua Wright, Mary Wu, Lauren Wynne, Zheng Xiang, Melvyn Yap, Julian A Zagalak, Davide Zecchin, Rachel Zillwood, Rebecca Matthews, Abigail Severn, Sajida Adam, Louise Enfield, Angela McBride, Kathleen Gärtner, Sarah Edwards, Fabiana Lorencatto, Susan Michie, Ed Manley, Maryam Shahmanesh, Hinal Lukha, Paulina Prymas, Hazel McBain, Robert Shortman, Leigh Wood, Claudia Davies, Bethany Williams, Kevin W Ng, Georgina H Cornish, Nikhil Faulkner, Andrew Riddell, Philip Hobson, Ana Agua-Doce, Kerol Bartolovic, Emma Russell, Lotte Carr, Emilie Sanchez, Daniel Frampton, Matthew Byott, Stavroula M Paraskevopoulou, Elise Crayton, Carly Meyer, Triantafylia Gkouleli, Andrea Stoltenberg, Veronica Ranieri, Tom Byrne, Fiona Roberts, and Emine Hatipoglu

Subjects
Adult, 2019-20 coronavirus outbreak, Infectious Disease Transmission, Patient-to-Professional, Coronavirus disease 2019 (COVID-19), Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), Health Personnel, Pneumonia, Viral, Viral transmission, Antibodies, Viral, Risk Assessment, Article, Betacoronavirus, Environmental health, Occupational Exposure, Pandemic, Health care, London, Medicine, Humans, Prospective Studies, Seroconversion, Pandemics, Cross Infection, business.industry, SARS-CoV-2, COVID-19, General Medicine, Occupational exposure, business, Coronavirus Infections
Published
2020

8. Studying the process of modification of lithium aluminum alloys

Author

Nataliya Kalinina, Tetyana Nosova, Stella Mamchur, Nataliya Tsokur, and Nikita Komarov

Subjects
General Medicine
Abstract

The effect of modification with dispersed compositions on the grain structure and mechanical properties of industrial aluminum alloys has been studied. Aluminum alloys of the Al-Si, Al-Mg-Sc, Al-Cu-Mn systems were modified with dispersed Mg2Si powder with a particle size of up to 200 nm. The amount of modifier to be added to the melt is calculated. The physicochemical properties of dispersed Mg2Si have been studied. Melting of the AMg6, 1570, 2219, AK9ch alloys in the initial state and with the treatment of Mg2Si melts have been carried out. The action of insoluble applications, isomorphic to aluminum, the similarity of the influence of soluble elements holds only when the amount of insoluble addition exceeds the number of crystals formed arbitrarily under the same conditions. Thus, with an increase in the amount of insoluble addition, in particular silicon carbide particles, the grain size first decreases and then remains constant. The mechanism of the influence of dispersed particles of magnesium silicide on the formation of the structure of hypoeutectic aluminum alloys during crystallization is that their bulk is pushed out by the crystallization front into the liquid phase and participates in the refinement of the structural components of the alloy. To determine the optimal amount of silicon carbide modifier, industrial melting and testing were performed on specimens that underwent heat treatment according to the T6 mode (quenching and artificial aging). The quality of cast aluminum alloys during modification depends on many factors: the nature of the dispersed phase, the temperature of the melt, and the modes of its mixing with the introduction of particles. Dependences of the particle size and the amount of the modifier on the mechanical properties of the alloys have been established. The mechanism of interaction of the modifier with aluminum melt during crystallization has been established. In industrial experiments, the most effective size of SiC particles for increasing the σm of the AK9ch alloy from 115 to 260 MPa in the as-cast state has been established. The optimal content of Mg2Si (0.10 %) for increasing the σm of aluminum alloys has been determined.

Published
2021

9. Tools Support for Linux Kernel Deductive Verification Workflow

Author

Denis Efremov and Nikita Komarov

Subjects
Workflow, Database, Computer science, Process (engineering), business.industry, Confidentiality, Linux kernel, computer.software_genre, Software engineering, business, computer, Formal verification, Classified information
Abstract

Errors in critically important systems may become very expensive. If such systems must provide confidentiality when working with some critically important data such as classified information or private know-how, an error cost may become difficult to evaluate. For these systems, formal verification methods should be used to prove they are error-free. In the paper, a case of formal verification of such system – a Linux kernel security module – is considered the chosen toolset, the verification process workflow are reviewed, along with some auxiliary tools required for this process and developed by the authors.

Published
2014

10. On the Implementation of Data-Breakpoints Based Race Detection for Linux Kernel Modules

Author

Nikita Komarov

Subjects
Class (computer programming), Race (biology), Software, business.industry, Computer science, Embedded system, Linux kernel, Operating system kernel, business, Race condition
Abstract

An important class of problems in software are race conditions. Errors of this class are becoming more common and more dangerous with the development of multi-processor and multi-core systems, especially in such a fundamentally parallel environment as an operating system kernel. The paper overviews some of existing approaches to detect race conditions including DataCollider system based on concurrent memory access tracking. RaceHound, a race condition detection system for Linux drivers based on similar principles as DataCollider is presented.

Published
2013

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