Modelação e análise não-linear do comportamento dinâmico de um passadiço pedonal

Dissertação para obtencão do Grau de Mestre em Engenharia Civil - Perfil Estruturas

Efeitos estruturais das sobrecargas rodoviárias definidas das normas mais utilizadas pela engenharia portuguesa em tabuleiros vigados de betão

Dissertação para obtenção do Grau de Mestre em Engenharia Civil

Molecular identification of the agent of Q fever – Coxiella burnetii – in domestic animals in State of Rio de Janeiro, Brazil

Introduction Over the last recent years, the number of Q fever cases have has increased throughout the world. An epidemiological investigation was performed in the area in which the first molecular documentation of Q fever in Brazil was previously reported. Methods Indirect immunofluorescence assay (IFA) and PCR of Coxiella burnetii targeting the htpAB gene were performed in samples from 14 dogs (blood); 1 cat (blood); 10 goats (blood, milk, vaginal swab and anal swab); 3 sheep (blood); and 2 horses (blood). Results Two dogs, two sheep and five goats were seroreactive. DNA was amplified from 6 milk and 2 blood samples from goats and from dogs, respectively. The sequence of the amplicons exhibited 99% sequence similarity with the homologous sequence of the htpAB gene of C. burnetii RSA 331 (GenBank - CP000890). Conclusions The results confirm C. burnetii infection in animals in Rio de Janeiro and reinforce the need for the surveillance of Q fever in Brazil.

Is autonomic function associated with left ventricular systolic function in Chagas heart disease patients undergoing treatment for heart failure?

Introduction The association between cardiac autonomic and left ventricular (LV) dysfunction in Chagas disease (ChD) is controversial. Methods A standardized protocol that includes the Valsalva maneuver, a respiratory sinus arrhythmia (RSA) test, and an echocardiographic examination was used. Spearman correlation coefficients (rho) were used to investigate associations. Results The study population consisted of 118 ChD patients undergoing current medical treatment, with an average LV ejection fraction of 51.4±2.6%. The LV ejection fraction and diastolic dimension were correlated with the Valsalva index (rho=0.358, p<0.001 and rho=-0.266, p=0.004, respectively) and the RSA (rho=0.391, p<0.001 and rho=-0.311, p<0.001, respectively). Conclusions The impairment of LV function is directly associated with a reduction of cardiac autonomic modulation in ChD.

Analysis of haemochromatosis mutations in the North West population

Background: Hereditary haemochromatosis is a heritable disorder caused by an inborn error in the metabolism of iron. It results in over absorption of iron by the body, which can manifest clinically as fatigue, arthritis, diabetes and cardiovascular problems. The highest prevalence for the genetic mutations that cause hereditary haemochromatosis can be found in the Irish population. Individuals with diabetes may also have haemochromatosis (and vice versa), due to the bi-directional relationship between iron metabolism and glucose metabolism. Objectives: To determine the incidence of the three haemochromatosis mutations C282Y, H63D & S65C, in a population from the North West of Ireland and to investigate whether there is an increased frequency of these three mutations in a diabetic population from the same region. Method: DNA was extracted from 500 whole blood samples (250 diabetic samples and 250 ‘control’ samples) using a Wizard™ kit. PCR was conducted utilising specific primers for each mutation and in accordance with a set protocol. Following amplification, PCR product was subjected to restriction endonuclease digestion, where different restriction enzymes (Rsa I, Nde II & Hinf I) were employed to determine the HFE genotype status of samples. Results: The incidence of C282Y homozygosity (1/83) and C282Y heterozygosity (1/6) in the ‘control’ group was similar to those reported for the general Irish population (1/83 and 1/5, respectively). Incidences of H63D homozygotes and H63D heterozygotes or ‘carriers’ in the diabetic population were greater than that of the ‘control’ population. A significant finding of this study was that of an incidence of 1/32 S65C carriers in the control population. This is, to our knowledge, the highest incidence of the genotype reported to date in the general Irish population. Statistical analysis showed that there was no significant differences between the HFE genotype frequencies in the Diabetic and Control Populations. Conclusion: Results of the study concord with published literature in terms of C282Y homozygosity and C282Y heterozygosity in the general Irish population. An increased frequency of the H63D mutation in diabetic individuals was also found but was not statistically significant. The biochemical effect of the H63D mutation is still unknown. The significance of such a high incidence of S65C carriers in the ‘control’ population warrants further investigation.

Càlcul distribuït en BOINC per el trencament de l'algorisme RC5

Aquest projecte té com a objectiu participar en el desafiament d'RSA Laboratories corresponent a trencar el criptosistema RC5-32-12-9 proposat. Per realitzar-ho s'ha triat realitzar un atac per força bruta, mitjançant el càlcul distribuït i, més concretament, utilitzant la Public Resource Computing. La plataforma escollida és la Berkeley Open Infrastructure for Network Computing (BOINC), coneguda per la seva utilització en grans projectes com ara SETI@home. En aquest projecte es posa en funcionament la infraestructura i es desenvolupen les aplicacions necessàries per iniciar els càlculs que haurien de permetre el trencament del criptosistema.

Estudio e implementación de una autoridad de certificación distribuida

Aquest projecte presenta, en primer lloc, un estudi dels protocols de generació de claus criptogràfiques i autoritats de certificació distribuïdes més destacables desenvolupades fins a l'actualitat. Posteriorment, implementem un protocol, que toleri les errades, de generació distribuïda de claus RSA sense servidor de confiança, orientat a xarxes ad-hoc. El protocol necessita la participació conjunta de n nodes per generar un mòdul RSA (N = pq), un exponent d'encriptació públic i les particions de l'exponent privat d, seguint un esquema llindar (t, n).

A public-key cryptosystem based on second order linear sequences

Based on Lucas functions, an improved version of the Diffie-Hellman distribution key scheme and to the ElGamal public key cryptosystem scheme are proposed, together with an implementation and computational cost. The security relies on the difficulty of factoring an RSA integer and on the difficulty of computing the discrete logarithm.

A public key encryption based on third order linear sequences

Based on third order linear sequences, an improvement version of the Diffie-Hellman distribution key scheme and the ElGamal public key cryptosystem scheme are proposed, together with an implementation and computational cost. The security relies on the difficulty of factoring an RSA integer and on the difficulty of computing the discrete logarithm.

Peri-prosthetic stress fractures after reversed shoulder arthroplasty

Introduction: Reversed shoulder prostheses have a semi-congruent design. Furthermore, the center of rotation is inferiorly displaced and a significant tension in the deltoid is often necessary to ensure the joint stability. Consequently, stress transmitted to peri-prosthetic bone may be increased, and could lead to stress fractures. We review a series of patients after reversed shoulder arthroplasty (RSA) and look specifically at the occurrence of postoperative peri-prosthetic stress fractures. Methods: Between 2001 and 2006, 46 consecutive RSA were performed. There were 26 women and 20 men with a mean age of 74 years (53-86). All had preoperative MRI or CT-scan, which did not reveal any fracture. All had a delto-pectoral approach with standard rehabilitation. Review was performed at a mean follow up of 30 months (6-60), and consisted of clinical and radiological (plain X-rays) examinations. Every time a fracture was suspected or in case of recurrent unexpected pain, CT-scan evaluations were performed. The occurrence of peri-prosthetic fractures was looked for. Results: Three patients (7%) sustained a scapular fracture (1 spinal and 2 acromial) without any trauma, between 3 and 6 months after the RSA. Furthermore, one of these patients developed 3 months later a spontaneous clavicular fracture, leading to an overall stress fracture rate of 9%. The four fractures were treated conservatively. Three malunions and one acromial non-union occurred. The range of motion in abduction and flexion decreased significantly after the fracture and stayed limited in all cases. All the three patients reported a recurrence of pain. Conclusion: Peri-prosthetic stress fractures, especially in the acromion and in the spine of the scapula are not unusual after RSA. The etiology is not well known. The increase of stress in peri-prosthetic bone may be due to the semi-congruent design and to an overtension of the deltoid. The management of this complication stays difficult. The conservative treatment leads to mal- or non-union, with persistent pain and limited range of motion.

Molecular identification of similar species of the genus Biomphalaria (Mollusca: Planorbidae) determined by a polymerase chain reaction-restriction fragment length polymorphism

The freshwater snails Biomphalaria straminea, B. intermedia, B. kuhniana and B. peregrina, are morphologically similar; based on this similarity the first three species were therefore grouped in the complex B. straminea. The morphological identification of these species is based on characters such as vaginal wrinkling, relation between prepuce: penial sheath:deferens vas and number of muscle layers in the penis wall. In this study the polymerase chain reaction restriction fragment length polymorphism technique was used for molecular identification of these molluscs. This technique is based on the amplification of the internal transcribed spacer regions ITS1 e ITS2 of the ribosomal RNA gene and subsequent digestion of these fragments by restriction enzymes. Six enzymes were tested: Dde I, Mnl I, Hae III, Rsa I, Hpa II e Alu I. The restriction patterns obtained with DdeI presented the best profile for separation of the four species of Biomphalaria. The profiles obtained with all the enzymes were used to estimate the genetic distances among the species through analysis of common banding patterns.

Comparative Analysis by Polymerase Chain Reaction Amplified Minicircles of Kinetoplast DNA of a Stable Strain of Trypanosoma cruzi from São Felipe, Bahia, its Clones and Subclones: Possibility of Predominance of a Principal Clone in this Area

Molecular characterization of one stable strain of Trypanosoma cruzi, the 21 SF, representative of the pattern of strains isolated from the endemic area of São Felipe, State of Bahia, Brazil, maintained for 15 years in laboratory by serial passages in mice and classified as biodeme Type II and zymodeme 2 has been investigated. The kinetoplast DNA (kDNA) of parental strain, 5 clones and 14 subclones were analyzed. Schizodeme was established by comparative study of the fragments obtained from digestion of the 330-bp fragments amplified by polymerase chain reaction (PCR) from the variable regions of the minicicles, and digested by restriction endonucleases Rsa I and Hinf I. Our results show a high percentual of similarity between the restriction fragment lenght polymorphism (RFLP) for the parental strain and its clones and among these individual clones and their subclones at a level of 80 to 100%.This homology indicates a predominance of the same "principal clone" in the 21SF strain and confirms the homogeneity previously observed at biological and isozymic analysis. These results suggest the possibility that the T. cruzi strains with similar biological and isoenzymic patterns, circulating in this endemic area, are representative of one dominant clone. The presence of "principal clones" could be responsible for a predominant tropism of the parasites for specific organs and tissues and this could contribute to the pattern of clinico-pathological manifestations of Chagas's disease in one geographical area.

Plasmodium falciparum malaria: rosettes are disrupted by quinine, artemisinin, mefloquine, primaquine, pyrimethamine, chloroquine and proguanil

An assay was developed measuring the disruption of rosettes between Plasmodium falciparuminfected (trophozoites) and uninfected erythrocytes by the antimalarial drugs quinine, artemisinin mefloquine, primaquine, pyrimethamine, chloroquine and proguanil. At 4 hr incubation rosettes were disrupted by all the drugs in a dose dependent manner. Artemisinin and quinine were the most effective anti-malarials at disrupting rosettes at their therapeutic concentrations with South African RSA 14, 15, 17 and The Gambian FCR-3 P. falciparum strains. The least effective drugs were proguanil and chloroquine. A combination of artemisinin and mefloquine was more effective than each drug alone. The combinations of pyrimethamine or primaquine, with quinine disrupted more rosettes than quinine alone. Quinine may be an effective drug in the treatment of severe malaria because the drug efficiently reduces the number of rosettes.

Xifratge d'arxius

Aquest memoria descriu els fonaments teòrics i la funcionalitat d'una aplicació per a cifrar arxius i directoris utilitzant la norma PKCS#5 dels laboratoris RSA, a més d'una modificació de la norma (algorisme TripelDES) per a aconseguir cifres més fortes.

Bovine papillomavirus type 2 detection in the urinary bladder of cattle with chronic enzootic haematuria

The bovine papillomavirus type 2 (BPV-2) involvement in the aetiology of chronic enzootic haematuria associated to bracken fern ingestion has been suggested for a long time. However, a few reports have shown the presence of the BPV-2 in urinary bladder tumors of cattle. The aim of this study was to investigate the presence of the BPV-2 infection in the urinary bladder of cattle with chronic enzootic haematuria in Brazilian cattle herds. Sixty-two urinary bladders were collected from adult cattle in beef herds from the north region of the state of Paraná, Brazil. According to clinical and pathological finds the specimens were distributed in three groups: the group A was constituted by 22 urinary bladders with macroscopic lesions collected at necropsy of cattle with clinical signs of chronic enzootic haematuria; the group B by 30 urinary bladders with macroscopic lesions collected in a slaughterhouse of cows coming from bracken fern-endemic geographical region; and the group C (control) by 10 urinary bladders without macroscopic lesions collected from asymptomatic cattle in a bracken fern-free geographical region. By a semi-nested polymerase chain reaction (PCR) assay, with an internal control, a fragment of the BPV-2 L1 gene with 386 bp length was amplified in 36 (58%) urinary bladder. The rate of BPV-2 positive urinary bladders was 50% (11/22) for group A, 80% (24/30) for group B, and 10% (1/10) for group C (control). The rate of the positive results found in groups A and B that included urinary bladder samples with macroscopic lesions was 67% (35/52) and the detection of the BPV-2 in both groups was significantly higher (P < 0.05) than in the control group. RFLP with Rsa I and Hae III enzymes evaluated the specificity of the BPV-2 amplicons. The PCR internal control that amplified a 626 bp fragment of the ND5 gene of the bovine mitochondrial genome was amplified in all analyzed samples and excluded false-negatives or invalid results in the semi-nested PCR. These results suggest the BPV-2 involvement in the chronic enzootic haematuria aetiology and open the perspective of the development of new strategies for the control of this disease that is the major cause of economical losses in beef herds from many Brazilian geographical regions.