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Edwards AJ, King MF, López-García M, Peckham D, Noakes CJ. Assessing the effects of transient weather conditions on airborne transmission risk in naturally ventilated hospitals. J Hosp Infect 2024; 148:1-10. [PMID: 38447806 DOI: 10.1016/j.jhin.2024.02.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 02/21/2024] [Accepted: 02/22/2024] [Indexed: 03/08/2024]
Abstract
BACKGROUND Many UK hospitals rely heavily on natural ventilation as their main source of airflow in patient wards. This method of ventilation can have cost and energy benefits, but it may lead to unpredictable flow patterns between indoor spaces, potentially leading to the unexpected transport of infectious material to other connecting zones. However, the effects of weather conditions on airborne transmission are often overlooked. METHODS A multi-zone CONTAM model of a naturally ventilated hospital respiratory ward, incorporating time-varying weather, was proposed. Coupling this with an airborne infection model, this study assessed the variable risk in interconnected spaces, focusing particularly on occupancy, disease and ventilation scenarios based on a UK respiratory ward. RESULTS The results suggest that natural ventilation with varying weather conditions can cause irregularities in the ventilation rates and interzonal flow rates of connected zones, leading to infrequent but high peaks in the concentration of airborne pathogens in particular rooms. This transient behaviour increases the risk of airborne infection, particularly through movement of pathogens between rooms, and highlights that large outbreaks may be more likely under certain conditions. This study demonstrated how ventilation rates achieved by natural ventilation are likely to fall below the recommended guidance, and that the implementation of supplemental mechanical ventilation can increase ventilation rates and reduce the variability in infection risks. CONCLUSION This model emphasizes the need for consideration of transient external conditions when assessing the risk of transmission of airborne infection in indoor environments.
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Affiliation(s)
- A J Edwards
- EPSRC Centre for Doctoral Training in Fluid Dynamics, University of Leeds, Leeds, UK.
| | - M-F King
- School of Civil Engineering, University of Leeds, Leeds, UK
| | | | - D Peckham
- Leeds Institute of Medical Research, University of Leeds, Leeds, UK; Leeds Teaching Hospitals NHS Trust, Leeds, UK
| | - C J Noakes
- School of Civil Engineering, University of Leeds, Leeds, UK
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King MF, Wilson AM, López-García M, Proctor J, Peckham DG, Clifton IJ, Dancer SJ, Noakes CJ. Why is mock care not a good proxy for predicting hand contamination during patient care? J Hosp Infect 2020; 109:44-51. [PMID: 33271214 DOI: 10.1016/j.jhin.2020.11.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 11/19/2020] [Accepted: 11/19/2020] [Indexed: 01/12/2023]
Abstract
BACKGROUND Healthcare worker (HCW) behaviours, such as the sequence of their contacts with surfaces and hand hygiene moments, are important for understanding disease transmission. AIM To propose a method for recording sequences of HCW behaviours during mock vs actual procedures, and to evaluate differences for use in infection risk modelling and staff training. METHODS Procedures for three types of care were observed under mock and actual settings: intravenous (IV) drip care, observational care and doctors' rounds on a respiratory ward in a university teaching hospital. Contacts and hand hygiene behaviours were recorded in real-time using either a handheld tablet or video cameras. FINDINGS Actual patient care demonstrated 70% more surface contacts than mock care. It was also 2.4 min longer than mock care, but equal in terms of patient contacts. On average, doctors' rounds took 7.5 min (2.5 min for mock care), whilst auxiliary nurses took 4.9 min for observational care (2.4 min for mock care). Registered nurses took 3.2 min for mock IV care and 3.8 min for actual IV care; this translated into a 44% increase in contacts. In 51% of actual care episodes and 37% of mock care episodes, hand hygiene was performed before patient contact; in comparison, 15% of staff delivering actual care performed hand hygiene after patient contact on leaving the room vs 22% for mock care. The number of overall touches in the patient room was a modest predictor of hand hygiene. Using a model to predict hand contamination from surface contacts for Staphylococcus aureus, Escherichia coli and norovirus, mock care underestimated micro-organisms on hands by approximately 30%.
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Affiliation(s)
- M F King
- School of Civil Engineering, University of Leeds, Leeds, UK.
| | - A M Wilson
- Department of Community, Environment and Policy, University of Arizona, Tucson, AZ, USA
| | | | - J Proctor
- School of Civil Engineering, University of Leeds, Leeds, UK
| | - D G Peckham
- School of Civil Engineering, University of Leeds, Leeds, UK; Leeds Cystic Fibrosis Trust Strategic Research Centre, University of Leeds, Leeds, UK
| | - I J Clifton
- School of Civil Engineering, University of Leeds, Leeds, UK; Leeds Cystic Fibrosis Trust Strategic Research Centre, University of Leeds, Leeds, UK; Leeds Institute of Medical Research at St. James's, University of Leeds, Leeds, UK; Adult Cystic Fibrosis Unit, St. James's University Hospital, Leeds, UK
| | - S J Dancer
- School of Applied Sciences, Edinburgh Napier University, Edinburgh, UK; Department of Microbiology, Hairmyres Hospital, NHS Lanarkshire, Glasgow, UK
| | - C J Noakes
- School of Civil Engineering, University of Leeds, Leeds, UK
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Wilson AM, Abney SE, King MF, Weir MH, López-García M, Sexton JD, Dancer SJ, Proctor J, Noakes CJ, Reynolds KA. COVID-19 and use of non-traditional masks: how do various materials compare in reducing the risk of infection for mask wearers? J Hosp Infect 2020; 105:640-642. [PMID: 32502581 PMCID: PMC7264937 DOI: 10.1016/j.jhin.2020.05.036] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 05/26/2020] [Indexed: 12/23/2022]
Affiliation(s)
- A M Wilson
- Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, AZ, USA.
| | - S E Abney
- Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, AZ, USA; College of Agriculture and Life Sciences, University of Arizona, Tucson, AZ, USA
| | - M-F King
- School of Civil Engineering, University of Leeds, Leeds, UK
| | - M H Weir
- Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, AZ, USA; College of Public Health, Ohio State University, Columbus, OH, USA
| | | | - J D Sexton
- Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, AZ, USA
| | - S J Dancer
- School of Applied Sciences, Edinburgh Napier University, Edinburgh, UK; Department of Microbiology, Hairmyres Hospital, Glasgow, UK
| | - J Proctor
- School of Civil Engineering, University of Leeds, Leeds, UK
| | - C J Noakes
- School of Civil Engineering, University of Leeds, Leeds, UK
| | - K A Reynolds
- Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, AZ, USA
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López-García M. Indetermined Moment Problems Related to $q$-Functional Equations. Theory Probab Appl 2020. [DOI: 10.1137/s0040585x97t990071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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López-García M, Nowicka M, Bendtsen C, Lythe G, Ponnambalam S, Molina-París C. Quantifying the phosphorylation timescales of receptor-ligand complexes: a Markovian matrix-analytic approach. Open Biol 2018; 8:180126. [PMID: 30232099 PMCID: PMC6170503 DOI: 10.1098/rsob.180126] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 08/10/2018] [Indexed: 01/22/2023] Open
Abstract
Cells interact with the extracellular environment by means of receptor molecules on their surface. Receptors can bind different ligands, leading to the formation of receptor-ligand complexes. For a subset of receptors, called receptor tyrosine kinases, binding to ligand enables sequential phosphorylation of intra-cellular residues, which initiates a signalling cascade that regulates cellular function and fate. Most mathematical modelling approaches employed to analyse receptor signalling are deterministic, especially when studying scenarios of high ligand concentration or large receptor numbers. There exist, however, biological scenarios where low copy numbers of ligands and/or receptors need to be considered, or where signalling by a few bound receptor-ligand complexes is enough to initiate a cellular response. Under these conditions stochastic approaches are appropriate, and in fact, different attempts have been made in the literature to measure the timescales of receptor signalling initiation in receptor-ligand systems. However, these approaches have made use of numerical simulations or approximations, such as moment-closure techniques. In this paper, we study, from an analytical perspective, the stochastic times to reach a given signalling threshold for two receptor-ligand models. We identify this time as an extinction time for a conveniently defined auxiliary absorbing continuous time Markov process, since receptor-ligand association/dissociation events can be analysed in terms of quasi-birth-and-death processes. We implement algorithmic techniques to compute the different order moments of this time, as well as the steady-state probability distribution of the system. A novel feature of the approach introduced here is that it allows one to quantify the role played by each kinetic rate in the timescales of signal initiation, and in the steady-state probability distribution of the system. Finally, we illustrate our approach by carrying out numerical studies for the vascular endothelial growth factor and one of its receptors, the vascular endothelial growth factor receptor of human endothelial cells.
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Affiliation(s)
- M López-García
- Department of Applied Mathematics, School of MathematicsSchool of Molecular and Cellular Biology, University of Leeds, LS2 9JT Leeds, UK
| | - M Nowicka
- Department of Applied Mathematics, School of MathematicsSchool of Molecular and Cellular Biology, University of Leeds, LS2 9JT Leeds, UK
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - C Bendtsen
- Quantitative Biology, Discovery Sciences, IMED Biotech Unit, AstraZeneca, Cambridge Science Park, Milton Road, CB4 0WG Cambridge, UK
| | - G Lythe
- Department of Applied Mathematics, School of MathematicsSchool of Molecular and Cellular Biology, University of Leeds, LS2 9JT Leeds, UK
| | - S Ponnambalam
- Endothelial Cell Biology Unit, School of Molecular and Cellular Biology, University of Leeds, LS2 9JT Leeds, UK
| | - C Molina-París
- Department of Applied Mathematics, School of MathematicsSchool of Molecular and Cellular Biology, University of Leeds, LS2 9JT Leeds, UK
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Artalejo JR, Gómez-Corral A, López-García M, Molina-París C. Stochastic descriptors to study the fate and potential of naive T cell clonotypes in the periphery. J Math Biol 2017; 74:673-708. [PMID: 27350044 PMCID: PMC5258823 DOI: 10.1007/s00285-016-1020-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 04/20/2016] [Indexed: 12/11/2022]
Abstract
The population of naive T cells in the periphery is best described by determining both its T cell receptor diversity, or number of clonotypes, and the sizes of its clonal subsets. In this paper, we make use of a previously introduced mathematical model of naive T cell homeostasis, to study the fate and potential of naive T cell clonotypes in the periphery. This is achieved by the introduction of several new stochastic descriptors for a given naive T cell clonotype, such as its maximum clonal size, the time to reach this maximum, the number of proliferation events required to reach this maximum, the rate of contraction of the clonotype during its way to extinction, as well as the time to a given number of proliferation events. Our results show that two fates can be identified for the dynamics of the clonotype: extinction in the short-term if the clonotype experiences too hostile a peripheral environment, or establishment in the periphery in the long-term. In this second case the probability mass function for the maximum clonal size is bimodal, with one mode near one and the other mode far away from it. Our model also indicates that the fate of a recent thymic emigrant (RTE) during its journey in the periphery has a clear stochastic component, where the probability of extinction cannot be neglected, even in a friendly but competitive environment. On the other hand, a greater deterministic behaviour can be expected in the potential size of the clonotype seeded by the RTE in the long-term, once it escapes extinction.
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Affiliation(s)
- J R Artalejo
- Department of Statistics and Operations Research, Faculty of Mathematics, Complutense University of Madrid, 28040, Madrid, Spain
| | - A Gómez-Corral
- Department of Statistics and Operations Research, Faculty of Mathematics, Complutense University of Madrid, 28040, Madrid, Spain
- Instituto de Ciencias Matemáticas, CSIC-UAM-UC3M-UCM, Calle Nicolás Cabrera 13-15, Campus de Cantoblanco UAM, 28049, Madrid, Spain
| | - M López-García
- Department of Applied Mathematics, School of Mathematics, University of Leeds, Leeds, LS2 9JT, UK
| | - C Molina-París
- Department of Applied Mathematics, School of Mathematics, University of Leeds, Leeds, LS2 9JT, UK.
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Gómez-Corral A, López-García M. On SIR epidemic models with generally distributed infectious periods: Number of secondary cases and probability of infection. INT J BIOMATH 2017. [DOI: 10.1142/s1793524517500243] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Recently, Clancy [SIR epidemic models with general infectious period distribution, Statist. Prob. Lett. 85 (2014) 1–5] has shown how SIR epidemics in which individuals’ infection periods are not necessarily exponentially distributed may be modeled in terms of a piecewise-deterministic Markov process (PDMP). In this paper, we present a more detailed description of the underlying PDMP, from which we analyze the population transmission number and the infection probability of a certain susceptible individual.
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Affiliation(s)
- A. Gómez-Corral
- Instituto de Ciencias Matemáticas, CSIC-UAM-UC3M-UCM, Calle Nicolás Cabrera 13-15, Madrid 28049, Spain
| | - M. López-García
- Department of Applied Mathematics, School of Mathematics, University of Leeds, Leeds LS2 9JT, UK
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Triñanes Y, Atienza G, Rial-Boubeta A, Calderón-Gómez C, Álvarez-Ariza M, de-las-Heras-Liñero E, López-García M. Áreas de mejora en el manejo clínico de la depresión: perspectiva de pacientes, familiares y profesionales. ACTA ACUST UNITED AC 2016; 31:365-372. [DOI: 10.1016/j.cali.2016.03.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 03/22/2016] [Accepted: 03/29/2016] [Indexed: 10/21/2022]
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Rosa-Rosa J, Leskelä S, Cristóbal-Lana E, Santón A, López-García M, Muñoz G, Pérez-Mies B, Biscuola M, Prat J, Oliva E, Soslow R, Matias-Guiu X, Palacios J. Molecular genetic heterogeneity in undifferentiated endometrial carcinomas. Mod Pathol 2016; 29:1390-1398. [PMID: 27491810 PMCID: PMC5708881 DOI: 10.1038/modpathol.2016.132] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 06/13/2016] [Accepted: 06/13/2016] [Indexed: 01/02/2023]
Abstract
Undifferentiated and dedifferentiated endometrial carcinomas are rare and highly aggressive subtypes of uterine cancer, not well characterized at a molecular level. To investigate whether dedifferentiated carcinomas carry molecular genetic alterations similar to those of pure undifferentiated carcinomas, and to gain insight into the pathogenesis of these tumors, we selected a cohort of 18 undifferentiated endometrial carcinomas, 8 of them with a well-differentiated endometrioid carcinoma component (dedifferentiated endometrioid carcinomas), and studied them by immunohistochemistry and massive parallel and Sanger sequencing. Whole-exome sequencing of the endometrioid and undifferentiated components, as well as normal myometrium, was also carried out in one case. According to The Cancer Genome Atlas classification, we distributed 95% of the undifferentiated carcinomas in this series as follows: (a) hypermutated tumors with loss of any mismatch repair protein expression and microsatellite instability (eight cases, 45%); (b) ultramutated carcinomas carrying mutations in the exonuclease domain of POLE (two cases, 11%); (c) high copy number alterations (copy-number high) tumors group exhibiting only TP53 mutations and high number of alterations detected by FISH (two cases, 11%); and (d) low copy number alterations (copy-number low) tumors with molecular alterations typical of endometrioid endometrial carcinomas (five cases, 28%). Two of the latter cases, however, also had TP53 mutations and higher number of alterations detected by FISH and could have progressed to a copy-number high phenotype. Most dedifferentiated carcinomas belonged to the hypermutated group, whereas pure undifferentiated carcinomas shared molecular genetic alterations with copy-number low or copy-number high tumors. These results indicate that undifferentiated and dedifferentiated endometrial carcinomas are molecularly heterogeneous tumors, which may have prognostic value.
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Affiliation(s)
- J.M. Rosa-Rosa
- Servicio de Anatomía Patológica, Hospital Universitario Ramón y Cajal, IRYCIS, Universidad de Alcalá, Madrid, Spain,Corresponding authors: Juan Manuel Rosa Rosa, Servicio de Anatomía Patológica, Hospital Ramón y Cajal, Ctra. Colmenar Viejo km 9,100, 28034 Madrid (Spain), ,
| | - S. Leskelä
- Servicio de Anatomía Patológica, Hospital Universitario Ramón y Cajal, IRYCIS, Universidad de Alcalá, Madrid, Spain
| | - E. Cristóbal-Lana
- Servicio de Anatomía Patológica, Hospital Universitario Ramón y Cajal, IRYCIS, Universidad de Alcalá, Madrid, Spain
| | - A. Santón
- Servicio de Anatomía Patológica, Hospital Universitario Ramón y Cajal, IRYCIS, Universidad de Alcalá, Madrid, Spain
| | - M.A. López-García
- Department of Pathology, Hospital Universitario Virgen del Rocío and Instituto de Biomedicina de Sevilla (IBIS), Sevilla, Spain
| | - G. Muñoz
- UCA en Genómica Traslacional, Hospital Universitario Ramón y Cajal, IRYCIS, Madrid, Spain
| | - B. Pérez-Mies
- Servicio de Anatomía Patológica, Hospital Universitario Ramón y Cajal, IRYCIS, Universidad de Alcalá, Madrid, Spain
| | - M Biscuola
- Department of Pathology, Hospital Universitario Virgen del Rocío and Instituto de Biomedicina de Sevilla (IBIS), Sevilla, Spain
| | - J. Prat
- Department of Pathology, Hospital de la Santa Creu i Sant Pau, Autonomous University of Barcelona, Spain
| | - E. Oliva
- Department of Pathology, Massachusetts General Hospital, Boston, MA, USA
| | - R.A. Soslow
- Department of Pathology, Gynecology Service, Memorial Sloan Kettering Cancer Center, New York, New York
| | - X. Matias-Guiu
- Department of Pathology and Molecular Genetics HUAV, Dept de Ciències Mèdiques Bàsiques, Institut de Recerca Biomedica de Lleida, Univeristy of Lleida, IRB Lleida, Lleida, Spain,Department of Pathology, Hospital Universitari de Bellvitge, Idibell, Barcelona, Spain
| | - J. Palacios
- Servicio de Anatomía Patológica, Hospital Universitario Ramón y Cajal, IRYCIS, Universidad de Alcalá, Madrid, Spain,Corresponding authors: Juan Manuel Rosa Rosa, Servicio de Anatomía Patológica, Hospital Ramón y Cajal, Ctra. Colmenar Viejo km 9,100, 28034 Madrid (Spain), ,
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Varela-Lema L, Paz-Valinas L, Atienza-Merino G, Zubizarreta-Alberdi R, Villares RV, López-García M. Appropriateness of newborn screening for classic galactosaemia: a systematic review. J Inherit Metab Dis 2016; 39:633-649. [PMID: 27116003 DOI: 10.1007/s10545-016-9936-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 03/28/2016] [Accepted: 04/06/2016] [Indexed: 12/11/2022]
Abstract
Currently, there is no universal agreement on galactosaemia screening, fundamentally because of the risk-benefit uncertainties. We conducted two exhaustive systematic searches in the main electronic databases (PubMed, Embase, Cochrane, etc.) to recover relevant information about the disease and screening test/s in order to support decision making in Spain. All of the 45 studies identified that covered disease issues were retrospective case series or cross-sectional analysis (level-4 evidence). Studies consistently found that the majority of patients presented characteristic symptomatology before diagnosis. Long term disabilities were not significantly correlated with age of diagnosis, onset of dietary restriction or strict diet compliance. The five studies that provided accuracy data used different cut-off points and verification tests, and thus differed in their definitions of a positive case (level-3b evidence). The estimated sensitivity was 100 % and the specificity 99.9 %. The false-positive rate ranged from 0.0005 % to 0.25 %, and the PPV from 0 % to 64.3 %. The comparative clinical effectiveness in relation to not screening or implementation of other programs is unknown. In summary, existing evidence remains insufficient to establish the appropriateness of newborn screening for galactosaemia screening, although health benefits could be expected if early diagnosis and treatment is achieved. If screening is implemented in Spain, it would be important that a pilot programme be implemented to assess false positive rate and ensure that early diagnosis is not delayed.
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Affiliation(s)
- L Varela-Lema
- Scientific-Technical Advice Unit (avalia-t), Galician Agency for Health Knowledge Management, ACIS, Santiago de Compostela, Spain.
| | - L Paz-Valinas
- Scientific-Technical Advice Unit (avalia-t), Galician Agency for Health Knowledge Management, ACIS, Santiago de Compostela, Spain
| | - G Atienza-Merino
- Scientific-Technical Advice Unit (avalia-t), Galician Agency for Health Knowledge Management, ACIS, Santiago de Compostela, Spain
| | - R Zubizarreta-Alberdi
- Department of Innovation and Public Health, Galician Health Authority, Santiago de Compostela, Spain
| | - R Vizoso Villares
- Department of Innovation and Public Health, Galician Health Authority, Santiago de Compostela, Spain
| | - M López-García
- Scientific-Technical Advice Unit (avalia-t), Galician Agency for Health Knowledge Management, ACIS, Santiago de Compostela, Spain
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López-García M. Erratum to Stochastic descriptors in an SIR epidemic model for heterogeneous individuals in small networks Mathematical Biosciences 271 (2016) 42–61. Math Biosci 2016; 276:164. [DOI: 10.1016/j.mbs.2016.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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López-García M. Stochastic descriptors in an SIR epidemic model for heterogeneous individuals in small networks. Math Biosci 2015; 271:42-61. [PMID: 26519788 DOI: 10.1016/j.mbs.2015.10.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2015] [Revised: 08/05/2015] [Accepted: 10/16/2015] [Indexed: 10/22/2022]
Abstract
We continue here the work initiated in [13], and analyse an SIR epidemic model for the spread of an epidemic among the members of a small population of N individuals, defined in terms of a continuous-time Markov chain X. We propose a structure by levels and sub-levels of the state space of the process X, and present two different orders, Orders A and B, for states within each sub-level, which are related to a matrix and a scalar formalism, respectively, when developing our analysis. Stochastic descriptors regarding the length and size of an outbreak, the maximum number of individuals simultaneously infected during an outbreak, the fate of a particular individual within the population, and the number of secondary cases caused by a certain individual until he recovers, are deeply analysed. Our approach is illustrated by carrying out a set of numerical results regarding the spread of the nosocomial pathogen Methicillin-resistant Staphylococcus Aureus among the patients within an intensive care unit. In this application, our interest is in analysing the effectiveness of control strategies (the isolation of the patient initiating the outbreak and the proper room configuration of the intensive care unit) that intrinsically introduce heterogeneities among the members of the population.
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Affiliation(s)
- M López-García
- Department of Applied Mathematics, School of Mathematics, University of Leeds, Leeds LS2 9JT, United Kingdom.
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13
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Paz-Valiñas L, de la Fuente-Cid R, de Rojas-Silva MV, López-Rodríguez I, López-García M. [Descemet's stripping automated endothelial keratoplasty (DEAEK). Systematic review of clinical-effectiveness and safety]. Arch Soc Esp Oftalmol 2015; 90:164-179. [PMID: 25443458 DOI: 10.1016/j.oftal.2014.09.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Revised: 03/06/2014] [Accepted: 09/04/2014] [Indexed: 06/04/2023]
Abstract
OBJECTIVE To conduct a systematic review of the efficacy/effectiveness, safety and cost of Descemet's stripping automated endothelial keratoplasty (DSAEK) technique in patients with corneal endothelial failure. METHODS Comprehensive literature search conducted in the main biomedical databases from January-May 2012. RESULTS Following a critical perusal of the total of 485 abstracts retrieved, 16 case series and one economic evaluation study were included. Corrected distance visual acuity and uncorrected distance visual acuity improved after treatment with DSAEK, attaining values of 0.6 to 0.8 and 0.5 respectively. The degree of post-DSAEK astigmatism was not significant with respect to baseline values. The main complications were graft dislocation-detachment (1.5-23%), primary failure (0-12%) and endothelial rejection (0.8-8.5%). CONCLUSIONS In Fuchs' dystrophy and bullous keratopathy, data on the effectiveness of DSAEK indicate post-intervention improvement in uncorrected and corrected distance visual acuity. Astigmatism arising after DSAEK was not significant. The most significant post-DSAEK complications are linked to the viability of the graft, with the most frequent complications being dislocation-detachment and, to a lesser extent, endothelial rejection. The studies that assess DSAEK are case series, and for the most part retrospective. The quality of this type of studies is both low and limited.
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Affiliation(s)
- L Paz-Valiñas
- Consellería de Sanidadem, Dirección Xeral de Innovación e Xestión da Saúde Pública, Axencia de Evaluación de Tecnoloxías Sanitarias de Galicia (avalia-t), Santiago de Compostela, La Coruña, España.
| | - R de la Fuente-Cid
- Consellería de Sanidadem, Dirección Xeral de Innovación e Xestión da Saúde Pública, Axencia de Evaluación de Tecnoloxías Sanitarias de Galicia (avalia-t), Santiago de Compostela, La Coruña, España
| | - M V de Rojas-Silva
- Servizo de Oftalmoloxía, Complexo Hospitalario Universitario A Coruña, La Coruña, España
| | - I López-Rodríguez
- Servizo de Oftalmoloxía, Complexo Hospitalario Universitario A Coruña, La Coruña, España
| | - M López-García
- Consellería de Sanidadem, Dirección Xeral de Innovación e Xestión da Saúde Pública, Axencia de Evaluación de Tecnoloxías Sanitarias de Galicia (avalia-t), Santiago de Compostela, La Coruña, España
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Cuesta-Barriuso R, Torres-Ortuño A, López-García M, Nieto-Munuera J. Effectiveness of an educational intervention of Physiotherapy in parents of children with haemophilia. Haemophilia 2014; 20:866-72. [DOI: 10.1111/hae.12447] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/30/2014] [Indexed: 11/30/2022]
Affiliation(s)
- R. Cuesta-Barriuso
- Grado de Fisioterapia; Departamento de Ciencias de la Salud; Facultad de Ciencias de la Salud; UCAM-Universidad Católica San Antonio; Murcia Spain
| | - A. Torres-Ortuño
- Departamento de Psiquiatría y Psicología Social; Facultad de Medicina; Universidad de Murcia; Murcia Spain
| | - M. López-García
- Servicio de Atención Temprana; Ayuntamiento de Miranda de Ebro; Burgos Spain
| | - J. Nieto-Munuera
- Departamento de Psiquiatría y Psicología Social; Facultad de Medicina; Universidad de Murcia; Murcia Spain
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Galisteo-López JF, López-García M, Blanco A, López C. Studying light propagation in self-assembled hybrid photonic-plasmonic crystals by fourier microscopy. Langmuir 2012; 28:9174-9179. [PMID: 22468889 DOI: 10.1021/la300448y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Hybrid metallodielectric systems where dielectric components are combined with metals supporting surface plasmons are able to spatially redistribute the electromagnetic field intensity within its volume through hybrid photonic-plasmonic modes. While most of the work done recently in this kind of systems has been focused on the way such redistribution takes place and how light couples to or is emitted from such samples, the way light propagation takes place has not been studied in depth. Here we consider light propagation in hybrid systems fabricated by self-assembly methods measuring their equifrequency surfaces both in reflection and emission configurations. Comparing spectroscopic measurements with equifrequency surfaces provides a deeper insight into the way light propagates in these structures, showing the possibilities they may present for several applications.
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Affiliation(s)
- J F Galisteo-López
- Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), C/Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain.
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16
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17
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Selhuber-Unkel C, Erdmann T, López-García M, Kessler H, Schwarz US, Spatz JP. Cell adhesion strength is controlled by intermolecular spacing of adhesion receptors. Biophys J 2010; 98:543-51. [PMID: 20159150 DOI: 10.1016/j.bpj.2009.11.001] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Revised: 10/23/2009] [Accepted: 11/02/2009] [Indexed: 12/23/2022] Open
Abstract
Spatial patterning of biochemical cues on the micro- and nanometer scale controls numerous cellular processes such as spreading, adhesion, migration, and proliferation. Using force microscopy we show that the lateral spacing of individual integrin receptor-ligand bonds determines the strength of cell adhesion. For spacings > or = 90 nm, focal contact formation was inhibited and the detachment forces as well as the stiffness of the cell body were significantly decreased compared to spacings < or = 50 nm. Analyzing cell detachment at the subcellular level revealed that rupture forces of focal contacts increase with loading rate as predicted by a theoretical model for adhesion clusters. Furthermore, we show that the weak link between the intra- and extracellular space is at the intracellular side of a focal contact. Our results show that cells can amplify small differences in adhesive cues to large differences in cell adhesion strength.
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Affiliation(s)
- C Selhuber-Unkel
- Max Planck-Institute for Metals Research, Department of New Materials and Biosystems, Stuttgart, Germany
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Loredo-Abdalá A, Cornejo-Barrera J, Carbajal-Rodríguez L, Sosa-Martínez C, López-García M, Vidales-Bayona C. [Comparative study of 1-deamino-8-D-arginine vasopressin, hydrochlorothiazide and chlorpropamide in the treatment of central diabetes insipidus]. Bol Med Hosp Infant Mex 1985; 42:314-8. [PMID: 4015810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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