ACUTE KIDNEY INJURY CAUSED BY Crotalus AND Bothrops SNAKE VENOM: A REVIEW OF EPIDEMIOLOGY, CLINICAL MANIFESTATIONS AND TREATMENT

SUMMARY Ophidic accidents are an important public health problem due to their incidence, morbidity and mortality. An increasing number of cases have been registered in Brazil in the last few years. Several studies point to the importance of knowing the clinical complications and adequate approach in these accidents. However, knowledge about the risk factors is not enough and there are an increasing number of deaths due to these accidents in Brazil. In this context, acute kidney injury (AKI) appears as one of the main causes of death and consequences for these victims, which are mainly young males working in rural areas. Snakes of the Bothrops and Crotalus genera are the main responsible for renal involvement in ophidic accidents in South America. The present study is a literature review of AKI caused by Bothrops and Crotalus snake venom regarding diverse characteristics, emphasizing the most appropriate therapeutic approach for these cases. Recent studies have been carried out searching for complementary therapies for the treatment of ophidic accidents, including the use of lipoic acid, simvastatin and allopurinol. Some plants, such as Apocynaceae, Lamiaceae and Rubiaceae seem to have a beneficial role in the treatment of this type of envenomation. Future studies will certainly find new therapeutic measures for ophidic accidents.

Gender Differences in Spatial Cognition: Wayfinding Performance and Sketch Mapping Activity of German Speakers

Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies

LATERAL FLOW ASSAY FOR CRYPTOCOCCAL ANTIGEN: AN IMPORTANT ADVANCE TO IMPROVE THE CONTINUUM OF HIV CARE AND REDUCE CRYPTOCOCCAL MENINGITIS-RELATED MORTALITY

SUMMARYAIDS-related cryptococcal meningitis continues to cause a substantial burden of death in low and middle income countries. The diagnostic use for detection of cryptococcal capsular polysaccharide antigen (CrAg) in serum and cerebrospinal fluid by latex agglutination test (CrAg-latex) or enzyme-linked immunoassay (EIA) has been available for over decades. Better diagnostics in asymptomatic and symptomatic phases of cryptococcosis are key components to reduce mortality. Recently, the cryptococcal antigen lateral flow assay (CrAg LFA) was included in the armamentarium for diagnosis. Unlike the other tests, the CrAg LFA is a dipstick immunochromatographic assay, in a format similar to the home pregnancy test, and requires little or no lab infrastructure. This test meets all of the World Health Organization ASSURED criteria (Affordable, Sensitive, Specific, User friendly, Rapid/robust, Equipment-free, and Delivered). CrAg LFA in serum, plasma, whole blood, or cerebrospinal fluid is useful for the diagnosis of disease caused by Cryptococcusspecies. The CrAg LFA has better analytical sensitivity for C. gattii than CrAg-latex or EIA. Prevention of cryptococcal disease is new application of CrAg LFA via screening of blood for subclinical infection in asymptomatic HIV-infected persons with CD4 counts < 100 cells/mL who are not receiving effective antiretroviral therapy. CrAg screening of leftover plasma specimens after CD4 testing can identify persons with asymptomatic infection who urgently require pre-emptive fluconazole, who will otherwise progress to symptomatic infection and/or die.

Juvenile Systemic Lupus Erythematosus in Portugal: Clinical and Immunological Patterns of Disease Expression in a Cohort of 56 Patients

Objective: To define the pattern of disease expression and to gain better understanding in patients with juvenile onset systemic lupus erythematosus (SLE) in Portugal. Methods: The features of unselected patients with systemic lupus erythematosus who had disease onset before the age of 18 years were retrospectively analysed in three Portuguese centres with Pediatric Rheumatology Clinic over a 24-year period (1987-2011). Demographic, clinical and laboratory manifestations, therapy and outcome were assessed. Results: A cohort of 56 patients with a mean age at disease onset of 12.6±4.04 years (mean±1SD) (range, 1.0-17.0 years) and a mean period of follow-up of 5.5±5.4 years. Forty six (82.1%) patients were female. The most common disease manifestations were musculoskeletal (87.5%), mucocutaneous (80.3%) and haematological abnormalities (75%). Lupus nephritis was diagnosed in 46.4% of patients and consisted of glomerular ne - phritis in all cases. Neuropsychiatric manifestations occurred in 21.4% but severe central nervous system complications were uncommon, as brain infarcts and organic brain syndrome in 4 (7.1%) patients. Antinuclear antibodies and anti-double stranded DNA were positive in most patients in (98.2% and 71.4% respectively), as well as low C3 and/or C4 were observed frequently (85.7%). Generally, most patients had a good response to therapy as demonstrated by a significant decreasing of SLEDAI score from disease presentation to the last evaluation. The SLEDAI at diagnosis, the maximum SLEDAI and the incidence of complications were significantly higher in patients with neurolupus and/or lupus nephritis. Therapy included oral steroids (87.5%), hydroxychloroquine (85.7%), azathioprine (55.4%), IV cyclophosphamide (28.6%) along with other drugs. Six (10.7%) patients were treated with rituximab. Long-term remission was achieved in 32%, disease was active in 68%, adverse reactions to therapy occurred in 53.6% and complications/severe manifestations in 23.2%. Two patients died, being active disease and severe infection the causes of death. Conclusions: This study suggests that in our patients the clinical and laboratory features observed were similar to juvenile systemic lupus erythematosus patients from other series. Clinical outcome was favourable in the present study. Complications from therapy were frequent. Objective: To define the pattern of disease expression and to gain better understanding in patients with juvenile onset systemic lupus erythematosus (SLE) in Portugal. Methods: The features of unselected patients with systemic lupus erythematosus who had disease onset before the age of 18 years were retrospectively analysed in three Portuguese centres with Pediatric Rheumatology Clinic over a 24-year period (1987-2011). Demographic,clinical and laboratory manifestations, therapy and outcome were assessed. Results: A cohort of 56 patients with a mean age at disease onset of 12.6±4.04 years (mean±1SD) (range, 1.0-17.0 years) and a mean period of follow-up of 5.5±5.4 years. Forty six (82.1%) patients were female. The most common disease manifestations were musculoskeletal (87.5%), mucocutaneous (80.3%) and haematological abnormalities (75%). Lupus nephritis was diagnosed in 46.4% of patients and consisted of glomerular ne - phritis in all cases. Neuropsychiatric manifestations occurred in 21.4% but severe central nervous system complications were uncommon, as brain infarcts and organic brain syndrome in 4 (7.1%) patients. Antinuclear antibodies and anti-double stranded DNA were positive in most patients in (98.2% and 71.4% respectively), as well as low C3 and/or C4 were observed frequently (85.7%). Generally, most patients had a good response to therapy as demonstrated by a significant decreasing of SLEDAI score from disease presentation to the last evaluation. The SLEDAI at diagnosis, the maximum SLEDAI and the incidence of complications were significantly higher in patients with neurolupus and/or lupus nephritis. Therapy included oral steroids (87.5%), hydroxychloroquine (85.7%), azathioprine (55.4%), IV cyclophosphamide (28.6%) along with other drugs. Six (10.7%) patients were treated with rituximab. Long-term remission was achieved in 32%, disease was active in 68%, adverse reactions to therapy occurred in 53.6% and complications/severe manifestations in 23.2%. Two patients died, being active disease and severe infection the causes of death. Conclusions: This study suggests that in our patients the clinical and laboratory features observed were similar to juvenile systemic lupus erythematosus patients from other series. Clinical outcome was favourable in the present study. Complications from therapy were frequent.

A Comparative Study of Cardiovascular Tolerability with Slow Extended Dialysis Versus Continuous Haemodiafiltration in the Critical Patient

Background: In the haemodynamically unstable patient the method of treatment of acute renal failure is still largely controversial. The purpose of our study was to compare slow extended dialysis with continuous haemodiafiltration in the critical patient with indication for renal replacement therapy and haemodynamic instability. Patients and Methods: This is a cohort study comparing in 63 ventilated critical patients a 12 month period when only continuous haemodiafiltration was used (n=25) with an equal period of slow extended dialysis (n=38). Our primary objective was to evaluate the impact of the dialytic procedure on cardiovascular stability in those patients. As secondary aims we considered system coagulation/thrombosis and predictors of mortality. In the two groups we analysed the first session performed, the second session performed and the average of all the sessions performed in each patient. Results: In these patients, mortality in the intensive care unit was high (68% in the continuous haemodiafiltration group and 63% in the slow extended dialysis group). We did not find any association between the dialytic technique used and death; only the APACHE score was a predictor of death. Slow extended dialysis was a predictor of haemodynamic stability, a negative predictor of sessions that had to be interrupted for haemodynamic instability, and a predictor of achieving the volume removal initially sought. Slow extended dialysis was also associated with less coagulation of the system. Conclusions: Our data suggested that slow extended dialysis use was not inferior to continuous haemodiafiltration use in terms of cardiovascular tolerability.

Benefits of Selective Vitamin D Receptor Activators in Kidney Transplanted Patients

Severe chronic kidney disease may lead to disturbances, such as hyperphosphatemia, increased secretion of fibroblast growth factor -23 (FGF -23) and vitamin D deficiency. These may increase plasmatic levels of parathyroid hormone, and decrease plasmatic levels of calcium. Altogether, these may contribute to the development of secondary hyperparathyroidism, and to abnormalities in mineral metabolism. Kidney transplantation is the best option to improve longevity and quality of life in end -stage chronic kidney disease patients. Vitamin D deficiency has been associated with cardiovascular disease, which is the leading cause of death in chronic kidney disease. Therefore, diagnosing this deficiency may be pivotal for minimizing mortality in chronic kidney disease, because pharmacological treatments for this deficiency may be prescribed. Calcitriol is indicated for the treatment of vitamin D deficiency, both in chronic kidney disease and in kidney transplanted patients. However, calcitriol may increase the plasmatic levels of calcium and phosphorous, which can lead to vascular calcifications, that have been associated with cardiovascular mortality. Selective vitamin D receptor activators are indicated for the treatment of vitamin D deficiency in chronic kidney disease. These have the advantage of being associated with lower increases of plasmatic levels of calcium and phosphorous. These drugs also seem to have additional effects that may minimise patient morbidity and mortality, especially due to potentially reducing cardiovascular events. Unfortunately, there are few studies about the use of these drugs in kidney transplanted patients. Here we present a review about the physiology of vitamin D, the consequences of its deficiency in chronic kidney disease and in kidney transplanted patients, and about the diagnosis and treatment of this deficiency. Finally, we discuss the new line of research about the efficacy and safety of selective vitamin D receptor activators in kidney transplanted patients.

The use of technology in Portuguese hospitals: The case of MRI

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics

Untitled: connecting layers of confusion, sensation and transformation

Dissertação para obtenção do Grau de Mestre em Arte e Ciência do Vidro

The impact of online brand community on electronic word-of-mouth communications

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

Prevalence of IgG and IgM anti-Toxoplasma antibodies in patients with HIV and acquired immunodeficiency syndrome (AIDS)

With the emergence of the human immunodeficiency virus (HIV), in patients with acquired immunodeficiency syndrome (AIDS), Toxoplasma gondii has arisen as an important opportunist pathogenic agent, especcially in the central nervous system, being the most common cause of intracerebral lesions. The incidence of Toxoplasma gondii in HIV-infected patients depends principally on the existence of latent Toxoplasma parasitosis in the population affected. Through the enzyme-linked immunosorbent assay (ELISA), IgG and IgM anti-Toxoplasma antibodies were found in 92 patients of which 46 (50.0%) were IgG seropositive, and only one case (1.0%) had IgM antibodies.Of the 92 patients: 53 were HIV seropositives and 39 had AIDS. The detection and monitoring of anti-Toxoplasma antibodies in HIV patients is essential, since in this group there is a high percentage risk of developing cerebral toxoplasmosis, which is the second cause of death in this type of patients.

The influence of off-screen landmarks on user orientation

Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.

Determinants of mother-baby relationship evaluated during pregnancy

ABSTRACT Background Mental health promotion is supported by a strong body of knowledge and is a matter of public health with the potential of a large impact on society. Mental health promotion programs should be implemented as soon as possible in life, preferably starting during pregnancy. Programs should focus on malleable determinants, introducing strategies to reduce risk factors or their impact on mother and child, and also on strengthening protective factors to increase resilience. The ambition of early detecting risk situations requires the development and use of tools to assess risk, and the creation of a responsive network of services based in primary health care, especially maternal consultation during pregnancy and the first months of the born child. The number of risk factors and the way they interact and are buffered by protective factors are relevant for the final impact. Maternal-fetal attachment (MFA) is not yet a totally understood and well operationalized concept. Methodological problems limit the comparison of data as many studies used small size samples, had an exploratory character or used different selection criteria and different measures. There is still a lack of studies in high risk populations evaluating the consequences of a weak MFA. Instead, the available studies are not very conclusive, but suggest that social support, anxiety and depression, self-esteem and self-control and sense of coherence are correlated with MFA. MFA is also correlated with health practices during pregnancy, that influence pregnancy and baby outcomes. MFA seems a relevant concept for the future mother baby interaction, but more studies are needed to clarify the concept and its operationalization. Attachment is a strong scientific concept with multiple implications for future child development, personality and relationship with others. Secure attachment is considered an essential basis of good mental health, and promoting mother-baby interaction offers an excellent opportunity to intervention programmes targeted at enhancing mental health and well-being. Understanding the process of attachment and intervening to improve attachment requires a comprehension of more proximal factors, but also a broader approach that assesses the impact of more distal social conditions on attachment and how this social impact is mediated by family functioning and mother-baby interaction. Finally, it is essential to understand how this knowledge could be translated in effective mental health promoting interventions and measures that could reach large populations of pregnant mothers and families. Strengthening emotional availability (EA) seems to be a relevant approach to improve the mother-baby relationship. In this review we have offered evidence suggesting a range of determinants of mother-infant relationship, including age, marital relationship, social disadvantages, migration, parental psychiatric disorders and the situations of abuse or neglect. Based on this theoretical background we constructed a theoretical model that included proximal and distal factors, risk and protective factors, including variables related to the mother, the father, their social support and mother baby interaction from early pregnancy until six months after birth. We selected the Antenatal Psychosocial Health Assessment (ALPHA) for use as an instrument to detect psychosocial risk during pregnancy. Method Ninety two pregnant women were recruited from the Maternal Health Consultation in Primary Health Care (PHC) at Amadora. They had three moments of assessment: at T1 (until 12 weeks of pregnancy) they filed out a questionnaire that included socio-demographic data, ALPHA, Edinburgh post-natal Depression Scale (EDPS), General Health Questionnaire (GHQ) and Sense of Coherence (SOC); at T2 (after the 20th weeks of pregnancy) they answered EDPS, SOC and MFA Scale (MFAS), and finally at T3 (6 months after birth), they repeated EDPS and SOC, and their interaction with their babies was videotaped and later evaluated using EA Scales. A statistical analysis has been done using descriptive statistics, correlation analysis, univariate logistic regression and multiple linear regression. Results The study has increased our knowledge on this particular population living in a multicultural, suburb community. It allow us to identify specific groups with a higher level of psychosocial risk, such as single or divorced women, young couples, mothers with a low level of education and those who are depressed or have a low SOC. The hypothesis that psychosocial risk is directly correlated with MFAS and that MFA is directly correlated with EA was not confirmed, neither the correlation between prenatal psychosocial risk and mother-baby EA. The study identified depression as a relevant risk factor in pregnancy and its higher prevalence in single or divorced women, immigrants and in those who have a higher global psychosocial risk. Depressed women have a poor MFA, and a lower structuring capacity and a higher hostility to their babies. In average, depression seems to reduce among pregnant women in the second part of their pregnancy. The children of immigrant mothers show a lower level of responsiveness to their mothers what could be transmitted through depression, as immigrant mothers have a higher risk of depression in the beginning of pregnancy and six months after birth. Young mothers have a low MFA and are more intrusive. Women who have a higher level of education are more sensitive and their babies showed to be more responsive. Women who are or have been submitted to abuse were found to have a higher level of MFA but their babies are less responsive to them. The study highlights the relevance of SOC as a potential protective factor while it is strongly and negatively related with a wide range of risk factors and mental health outcomes especially depression before, during and after pregnancy. Conclusions ALPHA proved to be a valid, feasible and reliable instrument to Primary Health Care (PHC) that can be used as a total sum score. We could not prove the association between psychosocial risk factors and MFA, neither between MFA and EA, or between psychosocial risk and EA. Depression and SOC seems to have a clear and opposite relevance on this process. Pregnancy can be considered as a maturational process and an opportunity to change, where adaptation processes occur, buffering risk, decreasing depression and increasing SOC. Further research is necessary to better understand interactions between variables and also to clarify a better operationalization of MFA. We recommend the use of ALPHA, SOC and EDPS in early pregnancy as a way of identifying more vulnerable women that will require additional interventions and support in order to decrease risk. At political level we recommend the reinforcement of Immigrant integration and the increment of education in women. We recommend more focus in health care and public health in mental health condition and psychosocial risk of specific groups at high risk. In PHC special attention should be paid to pregnant women who are single or divorced, very young, low educated and to immigrant mothers. This study provides the basis for an intervention programme for this population, that aims to reduce broad spectrum risk factors and to promote Mental Health in women who become pregnant. Health and mental health policies should facilitate the implementation of the suggested measures.

Thomsen-Friedenreich antigens in bladder cancer: evaluation of their prognostic value

RESUMO: Introdução. O cancro de bexiga é uma patologia comum que representa o 6° e o 5° cancro mais incidente em Portugal e na Itália, respetivamente. Em mais de metade dos casos ocorre reincidência durante o primeiro ano, requerendo acompanhamento clínico ao longo da vida. A instilação intravesical de Bacillus Calmette-Guérin (BCG) (uma estirpe atenuada do Mycobacterium bovis) representa uma imunoterapia eficaz no combate ao cancro de bexiga, no entanto, muitos aspetos da interação de BCG com as células tumorais bem como com as células do sistema imunitário permanecem por desvendar. As células tumorais de bexiga expressam frequentemente as formas sialiladas dos antigénios de Thomsen-Friedenreich (TF), i.e., sialil-T (sT) e sialil-Tn (sTn). Contudo ainda se desconhece o significado da sua expressão na malignidade tumoral e se afeta a eficácia da terapêutica BCG. Objetivo do estudo. Investigar o papel dos antigénios sT e sTn no fenótipo maligno de células de cancro de bexiga bem como na resposta mediada pelo sistema imunitário à terapia com BCG. Metodologia. Para tal, foram utilizadas as linhas celulares de cancro da bexiga HT1376 e MCR, geneticamente modificadas por transdução com vetores codificantes para as sialiltransferases ST3GAL1 ou ST6GALNAC1, de forma a expressar homogeneamente os antigénios sT ou sTn respetivamente. Estes modelos celulares foram estudados após confronto com BCG. O nível de BCG internalizado foi avaliado por citometria de fluxo. O perfil global de expressão genética dos modelos celulares antes e após incubação com BCG foi analisado pela tecnologia de microarray. O perfil de citocinas secretadas pelos modelos celulares após incubação com BCG, bem como de macrófagos estimulados pelo secretoma de células de cancro de bexiga que por sua vez foram estimuladas previamente por BCG, foi estudado pelo sistema multiplex de “imuno-esferas”. Resultados. A análise do transcritoma dos modelos celulares revelou que grupos de genes envolvidos em funções específicas foram modulados em paralelo nos dois modelos celulares, após transdução, independentemente da sialiltransferase expressa. Ou seja, em células que expressavam a sialiltransferase ST3GAL1 ou ST6GALNAC1, os genes envolvidos na regulação da segregação cromossómica e na reparação do DNA foram consistentemente regulados negativamente. Genes descritos na literatura como marcadores para o cancro de bexiga foram também modulados. A incubação com BCG resultou numa tendência ao aumento da expressão de genes relevantes na preservação e estabilidade genómica e menor malignidade, no entanto, apenas em células que expressavam sT ou sTn. Entre as dez citocinas testadas, apenas a IL-6 e IL-8 foram expressas pelas linhas celulares de cancro da bexiga, com indução destas após estimulação com BCG, e principalmente em células que expressavam ST3GAL1 ou ST6GALNAC1. Em macrófagos, citocinas inflamatórias, tais como IL-1β, IL-6 e TNFα, e a citocina anti-inflamatória IL-10, foram induzidas apenas pelo secretoma de células de cancro da bexiga confrontadas com BCG, com maior relevância quando estas expressavam ST3GAL1 ou ST6GALNAC1, prevendo a estimulação de macrófagos semelhantes aos de tipo M1 e uma melhor resposta à terapia com BCG. Conclusões. O efeito geral da expressão destas sialiltransferases e dos produtos enzimáticos sT ou sTn nas células de cancro de bexiga conduz a um fenótipo de maior malignidade. Contudo, a maior avidez de estas na produção de citocinas inflamatórias após confronto com BCG, bem como a maior capacidade de estimulação de macrófagos, predirá uma resposta à terapia com BCG mais eficaz em tumores que expressem os antigénios de TF sialilados. Tais conclusões são totalmente concordantes com os nossos mais recentes dados clínicos obtidos em colaboração, que mostram que em doentes com cancro de bexiga que expressam sTn respondem melhor a terapia BCG. ----------ABSTRACT: Background. Bladder cancer is a common malignancy representing the 6th and the 5th most incident cancer in Portugal and in Italy, respectively. More than half of the cases relapse within one year, requiring though a lifelong follow-up. Intravesical instillation of Bacillus Calmette-Guérin (BCG) (an attenuated strain of Mycobacterium bovis) represents an effective immunotherapy of bladder cancer, although many aspects of the interaction of BCG with cancer cells and host immune cells remain obscure. Bladder cancer cells often express the sialylated forms of the Thomsen-Friedenreich (TF), i.e., sialil-T (sT) e sialil-Tn (sTn). However, it’s still unknown the sense of such expression in tumour malignancy and in the BCG therapy efficacy. Aim of the study. To investigate the role of the sT and sTn antigens on the malignant phenotype of bladder cancer cells and the immune mediated response to BCG therapy. Experimental. We have utilized populations of the bladder cancer cell lines HT1376 and MCR, genetically modified by transduction with the sialyltransferases ST3GAL1 or ST6GALNAC1 to express homogeneously sT or sTn antigens. The level of BCG internalized was assessed by flow cytometry. The whole gene expression profile of BCG-challenged or unchallenged bladder cancer cell lines was studied by microarray technology. The profile of cytokines secreted by BCG-challenged bladder cancer cells and that of macrophages challenged by the secretome of BCG-challenged bladder cancer cells was studied by multiplex immune-beads assay. Results. Transcriptome analysis of the sialyltransferase-transduced cells revealed that groups of genes involved in specific functions were regulated in parallel in the two cell lines, regardless the sialyltransferase expressed. Namely, in sialyltransferase-expressing cells, genes involved in the proper chromosomal segregation and in the DNA repair were consistently down-regulated, while genes reported in literature as markers for bladder cancer were modulated. BCG-challenging induced a tendency to up-regulation of the genes preserving genomic stability and reducing malignancy, but only in cells expressing either sT or sTn. Among the ten cytokines tested, only IL-6 and IL-8 were expressed by bladder cancer cell lines and up-regulated by BCG-challenging, mainly in sialyltransferases-expressing cells. In macrophages, inflammatory cytokines, such as IL-1β, IL-6 and TNFα, and the antinflammatory IL-10 were induced only by the secretome of BCG-challenged bladder cancer cells, particularly when expressing either sialyltransferase, predicting the stimulation of M1-like macrophages and a better response to BCG therapy. Conclusions. The general effect of the expression of the two sialyltransferases and their products in the bladder cancer cells is toward a more malignant phenotype. However, the stronger ability of sialyltransferase expressing cells to produce inflammatory cytokines upon BCG-challenging and to stimulate macrophages predicts a more effective response to BCG in tumours expressing the sialylated TF antigens. This is fully consistent with our recent clinical data obtained in collaboration, showing that patients with bladder cancer expressing sTn respond better to BCG therapy.

Mechanical characterization of aortas using 2D ultrasound elastography

Rupture of aortic aneurysms (AA) is a major cause of death in the Western world. Currently, clinical decision upon surgical intervention is based on the diameter of the aneurysm. However, this method is not fully adequate. Noninvasive assessment of the elastic properties of the arterial wall can be a better predictor for AA growth and rupture risk. The purpose of this study is to estimate mechanical properties of the aortic wall using in vitro inflation testing and 2D ultrasound (US) elastography, and investigate the performance of the proposed methodology for physiological conditions. Two different inflation experiments were performed on twelve porcine aortas: 1) a static experiment for a large pressure range (0 – 140 mmHg); 2) a dynamic experiment closely mimicking the in vivo hemodynamics at physiological pressures (70 – 130 mmHg). 2D raw radiofrequency (RF) US datasets were acquired for one longitudinal and two cross-sectional imaging planes, for both experiments. The RF-data were manually segmented and a 2D vessel wall displacement tracking algorithm was applied to obtain the aortic diameter–time behavior. The shear modulus G was estimated assuming a Neo-Hookean material model. In addition, an incremental study based on the static data was performed to: 1) investigate the changes in G for increasing mean arterial pressure (MAP), for a certain pressure difference (30, 40, 50 and 60 mmHg); 2) compare the results with those from the dynamic experiment, for the same pressure range. The resulting shear modulus G was 94 ± 16 kPa for the static experiment, which is in agreement with literature. A linear dependency on MAP was found for G, yet the effect of the pressure difference was negligible. The dynamic data revealed a G of 250 ± 20 kPa. For the same pressure range, the incremental shear modulus (Ginc) was 240 ± 39 kPa, which is in agreement with the former. In general, for all experiments, no significant differences in the values of G were found between different image planes. This study shows that 2D US elastography of aortas during inflation testing is feasible under controlled and physiological circumstances. In future studies, the in vivo, dynamic experiment should be repeated for a range of MAPs and pathological vessels should be examined. Furthermore, the use of more complex material models needs to be considered to describe the non-linear behavior of the vascular tissue.

Resilience in organizations: The perspective of managers in Portugal and Germany

The concept of organizational resilience has become popular in Organizational Studies during the last decades - yet researchers have not been able to find one commonly accepted definition for what exactly it is. What are the drivers of resilience in organizations? Are there certain cultural factors and national differences regarding the perception of the concept? This paper aims to answer these questions from a perspective of within institutions. A group of managers from different corporations in Portugal and Germany has been interviewed in order to understand how managers experience and characterize organizational resilience. Based on qualitative inductive research the results show that organizational resilience is built on four main drivers: a sense of proximity, a sense of openness, a sense of challenge and a sense for structure.