A two-scale failure model for heterogeneous materials: numerical implementation based on the finite element method

This is the accepted version of the following article: Toro, S., Sánchez, P.J., Huespe, A.E., Giusti, S.M., Blanco, P.J. and Feijóo, R.A. (2014), A two-scale failure model for heterogeneous materials: numerical implementation based on the finite element method. Int. J. Numer. Meth. Engng., 97: 313–351. doi: 10.1002/nme.4576, which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/nme.4576/abstractIn the first part of this contribution, a brief theoretical revision of the mechanical and variational foundations of a Failure-Oriented Multiscale Formulation (FOMF) devised for modeling failure in heterogeneous materials is described. The proposed model considers two well separated physical length scales, namely: (i) the “macro” scale where nucleation and evolution of a cohesive surface is considered as a medium to characterize the degradation phenomenon occurring at the lower length scale, and (ii) the “micro” scale where some mechanical processes that lead to the material failure are taking place, such as strain localization, damage, shear band formation, etc. These processes are modeled using the concept of Representative Volume Element (RVE). On the macro scale, the traction separation response, characterizing the mechanical behavior of the cohesive interface, is a result of the failure processes simulated in the micro scale. The traction separation response is obtained by a particular homogenization technique applied on specific RVE subdomains. Standard, as well as, Non-Standard boundary conditions are consistently derived in order to preserve “objectivity” of the homogenized response with respect to the micro-cell size. In the second part of the paper, and as an original contribution, the detailed numerical implementation of the two-scale model based on the Finite Element Method is presented. Special attention is devoted to the topics which are distinctive of the FOMF, such as: (i) the finite element technologies adopted in each scale along with their corresponding algorithmic expressions, (ii) the generalized treatment given to the kinematical boundary conditions in the RVE and (iii) how these kinematical restrictions affect the capturing of macroscopic material instability modes and the posterior evolution of failure at the RVE level. Finally, a set of numerical simulations is performed.Peer ReviewedPostprint (author’s final draft

Prevalence of Pertussis Antibodies in Maternal Blood, Cord Serum, and Infants From Mothers With and Those Without Tdap Booster Vaccination During Pregnancy in Argentina

Fil: Fallo, Aurelia A. Department of Pediatric Infectious Diseases, School of Medicine, Hospital de Niños "Ricardo Gutiérrez," University of Buenos Aires; Argentina.Fil: Neyro, Silvina E. Department of Pediatric Infectious Diseases, School of Medicine, Hospital de Niños "Ricardo Gutiérrez," University of Buenos Aires; Argentina.Fil: Manonelles, Gabriela V. Department of Pediatric Infectious Diseases, School of Medicine, Hospital de Niños "Ricardo Gutiérrez," University of Buenos Aires; Argentina.Fil: Lara, Claudia. Administración Nacional de Laboratorios e Institutos de Salud “Dr. Carlos G. Malbrán” (ANLIS); Argentina.Fil: Hozbor, Daniela. Laboratorio VacSal, Instituto de Biotecnología y Biología Molecular (IBBM), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CCT-CONICET; Argentina.Fil: Zintgraff, Jonathan. Administración Nacional de Laboratorios e Institutos de Salud “Dr. Carlos G. Malbrán” (ANLIS); Argentina.Fil: Mazzeo, Silvina. Departments of Obstetrics and Gynecology, Hospital D. F. Santojanni, Buenos Aires; Argentina.Fil: Davison, Héctor E. Departments of Obstetrics and Gynecology, Hospital D. F. Santojanni, Buenos Aires; Argentina.Fil: González, Susana. Pediatrics, Hospital D. F. Santojanni, Buenos Aires; Argentina.Fil: Zapulla, Estella. Pediatrics, Hospital D. F. Santojanni, Buenos Aires; ArgentinaFil: Canle, Oscar. Blood Center, Hospital de Niños "Ricardo Gutiérrez," Buenos Aires; ArgentinaFil: Huespe, Miguel. Departments of Obstetrics and Gynecology, Hospital D. F. Santojanni, Buenos Aires; Argentina.Fil: Galas, Marcelo. Administración Nacional de Laboratorios e Institutos de Salud “Dr. Carlos G. Malbrán” (ANLIS); Argentina.Fil: López, Eduardo L. Department of Pediatric Infectious Diseases, School of Medicine, Hospital de Niños "Ricardo Gutiérrez," University of Buenos Aires; Argentina.Morbidity and mortality rates for pertussis in infants are high because disease often occurs before the onset of routine immunization or in those who do not complete a primary immunization series. Pertussis immunization is recommended during pregnancy to achieve antibody levels sufficient to protect young infants. To our knowledge, no previous reports of maternal pertussis immunization results in Latin America exist in the literature

Development and evaluation of a machine learning-based in-hospital COVID-19 disease outcome predictor (CODOP): A multicontinental retrospective study

New SARS-CoV-2 variants, breakthrough infections, waning immunity, and sub-optimal vaccination rates account for surges of hospitalizations and deaths. There is an urgent need for clinically valuable and generalizable triage tools assisting the allocation of hospital resources, particularly in resource-limited countries. We developed and validate CODOP, a machine learning-based tool for predicting the clinical outcome of hospitalized COVID-19 patients. CODOP was trained, tested and validated with six cohorts encompassing 29223 COVID-19 patients from more than 150 hospitals in Spain, the USA and Latin America during 2020-22. CODOP uses 12 clinical parameters commonly measured at hospital admission for reaching high discriminative ability up to 9 days before clinical resolution (AUROC: 0.90-0.96), it is well calibrated, and it enables an effective dynamic risk stratification during hospitalization. Furthermore, CODOP maintains its predictive ability independently of the virus variant and the vaccination status. To reckon with the fluctuating pressure levels in hospitals during the pandemic, we offer two online CODOP calculators, suited for undertriage or overtriage scenarios, validated with a cohort of patients from 42 hospitals in three Latin American countries (78-100% sensitivity and 89-97% specificity). The performance of CODOP in heterogeneous and geographically disperse patient cohorts and the easiness of use strongly suggest its clinical utility, particularly in resource-limited countries

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Background: Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. // Methods: We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung's disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. // Findings: We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung's disease) from 264 hospitals (89 in high-income countries, 166 in middle-income countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in low-income countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. // Interpretation: Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between low-income, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

A two-scale failure model for heterogeneous materials: numerical implementation based on the finite element method

This is the accepted version of the following article: Toro, S., Sánchez, P.J., Huespe, A.E., Giusti, S.M., Blanco, P.J. and Feijóo, R.A. (2014), A two-scale failure model for heterogeneous materials: numerical implementation based on the finite element method. Int. J. Numer. Meth. Engng., 97: 313–351. doi: 10.1002/nme.4576, which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/nme.4576/abstractIn the first part of this contribution, a brief theoretical revision of the mechanical and variational foundations of a Failure-Oriented Multiscale Formulation (FOMF) devised for modeling failure in heterogeneous materials is described. The proposed model considers two well separated physical length scales, namely: (i) the “macro” scale where nucleation and evolution of a cohesive surface is considered as a medium to characterize the degradation phenomenon occurring at the lower length scale, and (ii) the “micro” scale where some mechanical processes that lead to the material failure are taking place, such as strain localization, damage, shear band formation, etc. These processes are modeled using the concept of Representative Volume Element (RVE). On the macro scale, the traction separation response, characterizing the mechanical behavior of the cohesive interface, is a result of the failure processes simulated in the micro scale. The traction separation response is obtained by a particular homogenization technique applied on specific RVE subdomains. Standard, as well as, Non-Standard boundary conditions are consistently derived in order to preserve “objectivity” of the homogenized response with respect to the micro-cell size. In the second part of the paper, and as an original contribution, the detailed numerical implementation of the two-scale model based on the Finite Element Method is presented. Special attention is devoted to the topics which are distinctive of the FOMF, such as: (i) the finite element technologies adopted in each scale along with their corresponding algorithmic expressions, (ii) the generalized treatment given to the kinematical boundary conditions in the RVE and (iii) how these kinematical restrictions affect the capturing of macroscopic material instability modes and the posterior evolution of failure at the RVE level. Finally, a set of numerical simulations is performed.Peer Reviewe

Estudio de seroprevalencia de coqueluche en adultos jóvenes, mujeres en puerperio inmediato y sangre del cordón umbilical

Pertussis is a vaccine-preventable disease that affects people of all ages. Young adults who have lost their immunity to pertussis are the major source of infection in infants. Given the steady increase of pertussis cases, new prevention strategies are required. Objective. To assess pertussis seroprevalence in adult blood donors, post-partum women, and umbilical cords. Metod. Measurement of total titers of anti-Bordetella spp. (Bordetella) antibodies using an enzyme-linked immunosorbent assay. Serum samples from 103 donors, 101 post-partum women and 100 umbilical cords were analyzed. Titers ≤80 were considered of low impact against the disease. The assessment included transplacental transfer of antibodies and the umbilical cord/maternal ratio of antibody titers. Results. Donors mean age was: 28 ± 6 years old. Median anti-Bordetella titers: 320; interquartile range (IQR):160-320; 10% had titers ≤80. Post-partum women mean age was: 26 ± 6 years old. Median anti-Bordetella titers:160 (IQR:80-320), with titers significantly lower than in female donors (p= 0.00002). Titers ≤80 were found in 30% of post-partum women. Median anti-Bordetella titers in umbilical cords: 160 (IQR: 80-160). Titers ≤80 were more frequently found in umbilical cords than in mothers (44% versus 30%, p= 0.04). Transplacental transfer was 0.83. Umbilical cord titers were equal to maternal titers in 54% of cases, lower in 37%, and higher only in 8%. Conclusion. Titers of anti-Bordetella antibodies in post-partum women were significantly lower than in female blood donors. Titers ≤80 were found in 30% of post-partum women and 44% of umbilical cords. These data may account for the high rates of pertussis in young infants who have not yet completed their vaccination schedule.Facultad de Ciencias Exacta

Estudio de seroprevalencia de coqueluche en adultos jóvenes, mujeres en puerperio inmediato y sangre del cordón umbilical

Pertussis is a vaccine-preventable disease that affects people of all ages. Young adults who have lost their immunity to pertussis are the major source of infection in infants. Given the steady increase of pertussis cases, new prevention strategies are required. Objective. To assess pertussis seroprevalence in adult blood donors, post-partum women, and umbilical cords. Metod. Measurement of total titers of anti-Bordetella spp. (Bordetella) antibodies using an enzyme-linked immunosorbent assay. Serum samples from 103 donors, 101 post-partum women and 100 umbilical cords were analyzed. Titers ≤80 were considered of low impact against the disease. The assessment included transplacental transfer of antibodies and the umbilical cord/maternal ratio of antibody titers. Results. Donors mean age was: 28 ± 6 years old. Median anti-Bordetella titers: 320; interquartile range (IQR):160-320; 10% had titers ≤80. Post-partum women mean age was: 26 ± 6 years old. Median anti-Bordetella titers:160 (IQR:80-320), with titers significantly lower than in female donors (p= 0.00002). Titers ≤80 were found in 30% of post-partum women. Median anti-Bordetella titers in umbilical cords: 160 (IQR: 80-160). Titers ≤80 were more frequently found in umbilical cords than in mothers (44% versus 30%, p= 0.04). Transplacental transfer was 0.83. Umbilical cord titers were equal to maternal titers in 54% of cases, lower in 37%, and higher only in 8%. Conclusion. Titers of anti-Bordetella antibodies in post-partum women were significantly lower than in female blood donors. Titers ≤80 were found in 30% of post-partum women and 44% of umbilical cords. These data may account for the high rates of pertussis in young infants who have not yet completed their vaccination schedule.Facultad de Ciencias Exacta

Estudio de seroprevalencia de coqueluche en adultos jóvenes, mujeres en puerperio inmediato y sangre del cordón umbilical

Pertussis is a vaccine-preventable disease that affects people of all ages. Young adults who have lost their immunity to pertussis are the major source of infection in infants. Given the steady increase of pertussis cases, new prevention strategies are required. Objective. To assess pertussis seroprevalence in adult blood donors, post-partum women, and umbilical cords. Metod. Measurement of total titers of anti-Bordetella spp. (Bordetella) antibodies using an enzyme-linked immunosorbent assay. Serum samples from 103 donors, 101 post-partum women and 100 umbilical cords were analyzed. Titers ≤80 were considered of low impact against the disease. The assessment included transplacental transfer of antibodies and the umbilical cord/maternal ratio of antibody titers. Results. Donors mean age was: 28 ± 6 years old. Median anti-Bordetella titers: 320; interquartile range (IQR):160-320; 10% had titers ≤80. Post-partum women mean age was: 26 ± 6 years old. Median anti-Bordetella titers:160 (IQR:80-320), with titers significantly lower than in female donors (p= 0.00002). Titers ≤80 were found in 30% of post-partum women. Median anti-Bordetella titers in umbilical cords: 160 (IQR: 80-160). Titers ≤80 were more frequently found in umbilical cords than in mothers (44% versus 30%, p= 0.04). Transplacental transfer was 0.83. Umbilical cord titers were equal to maternal titers in 54% of cases, lower in 37%, and higher only in 8%. Conclusion. Titers of anti-Bordetella antibodies in post-partum women were significantly lower than in female blood donors. Titers ≤80 were found in 30% of post-partum women and 44% of umbilical cords. These data may account for the high rates of pertussis in young infants who have not yet completed their vaccination schedule.Facultad de Ciencias Exacta

Estudio de seroprevalencia de coqueluche en adultos jóvenes, mujeres en puerperio inmediato y sangre del cordón umbilical

Pertussis is a vaccine-preventable disease that affects people of all ages. Young adults who have lost their immunity to pertussis are the major source of infection in infants. Given the steady increase of pertussis cases, new prevention strategies are required. Objective. To assess pertussis seroprevalence in adult blood donors, post-partum women, and umbilical cords. Metod. Measurement of total titers of anti-Bordetella spp. (Bordetella) antibodies using an enzyme-linked immunosorbent assay. Serum samples from 103 donors, 101 post-partum women and 100 umbilical cords were analyzed. Titers ≤80 were considered of low impact against the disease. The assessment included transplacental transfer of antibodies and the umbilical cord/maternal ratio of antibody titers. Results. Donors mean age was: 28 ± 6 years old. Median anti-Bordetella titers: 320; interquartile range (IQR):160-320; 10% had titers ≤80. Post-partum women mean age was: 26 ± 6 years old. Median anti-Bordetella titers:160 (IQR:80-320), with titers significantly lower than in female donors (p= 0.00002). Titers ≤80 were found in 30% of post-partum women. Median anti-Bordetella titers in umbilical cords: 160 (IQR: 80-160). Titers ≤80 were more frequently found in umbilical cords than in mothers (44% versus 30%, p= 0.04). Transplacental transfer was 0.83. Umbilical cord titers were equal to maternal titers in 54% of cases, lower in 37%, and higher only in 8%. Conclusion. Titers of anti-Bordetella antibodies in post-partum women were significantly lower than in female blood donors. Titers ≤80 were found in 30% of post-partum women and 44% of umbilical cords. These data may account for the high rates of pertussis in young infants who have not yet completed their vaccination schedule.Facultad de Ciencias Exacta