The presence and lack of Fermi acceleration in nonintegrable billiards

The unlimited energy growth ( Fermi acceleration) of a classical particle moving in a billiard with a parameter-dependent boundary oscillating in time is numerically studied. The shape of the boundary is controlled by a parameter and the billiard can change from a focusing one to a billiard with dispersing pieces of the boundary. The complete and simplified versions of the model are considered in the investigation of the conjecture that Fermi acceleration will appear in the time-dependent case when the dynamics is chaotic for the static boundary. Although this conjecture holds for the simplified version, we have not found evidence of Fermi acceleration for the complete model with a breathing boundary. When the breathing symmetry is broken, Fermi acceleration appears in the complete model.

Estrógenos em água: otimização da extração em fase sólida utilizando ferramentas quimiométricas

Muitos métodos analíticos estão sendo desenvolvidos visando à determinação de contaminantes orgânicos, especialmente alteradores endócrinos. Tais métodos baseiam-se geralmente na extração em fase sólida (SPE) seguida por determinação cromatográfica (CG ou HPLC). No presente trabalho utilizou-se ferramentas quimiométricas no processo de SPE para avaliar os principais fatores que influenciam tal processo e as interações entre os mesmos. Foram analisadas matrizes de água subterrânea fortificada com hormônios (17 b estradiol, estrona e 17 b etinilestradiol) e a determinação analítica foi feita por HPLC/Fluorescência. Um planejamento fatorial completo foi utilizado. Os fatores escolhidos incluíram: condicionamento da fase sólida, concentração dos analitos, volume da amostra e solvente de eluição. As melhores condições obtidas foram: 500 mL da amostra, condicionamento da fase sólida (C18) com acetona (4mL), metanol (6 mL) e água pH 3(10 mL), e eluição dos analitos com 4 mL de acetona.

Avaliação do método das adições de analito para a determinação de sódio em álcool combustível por espestrometria de emissão atômica em chama

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Contribution of ocular B-mode and triplex Doppler in the evaluation of 10 Poodle dogs with cataracts

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Deletion of Epstein-Barr virus latent membrane protein 1 gene in United States and Brazilian Hodgkin's disease and reactive lymphoid tissue: High frequency of a 30-bp deletion

A 30-basepair (bp) deletion in the Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1) gene has been reported in nasopharyngeal carcinoma and EBV-associated malignant lymphomas. Prior studies have found the deletion in about 10% to 28% of cases of Hodgkin's disease (HD), particularly in cases with aggressive histology. We studied the prevalence of 30-bp LMP1 gene deletion in EBV-positive HD in the United States (US) (12 cases) and Brazil (26 cases) with comparison to reactive lymphoid tissues (21 cases) and HD without EBV-positive Reed-Sternberg cells (15 cases). We studied the status of the LMP1 gene by Southern blot hybridization of polymerase chain reaction (PCR) products obtained after amplification with primers spanning the site of the deletion. We also performed EBV typing, EBER1 in situ hybridization, and LMP1 protein immunohistochemistry. EBV was detected in 12/26 (46%) cases of HD from the US and 26/27 (96%) cases of Brazilian HD. The 30-bp LMP1 gene deletion was observed in 4/12 (33%) cases of EBV-positive HD from US, and 12/26 (46%) cases of Brazilian EBV-positive HD, including 3 cases of type B EBV, as compared with 12/21 (57%) reactive lymphoid tissues and 9/15 (60%) cases of EBV-negative HD. US and Brazilian HD showed a higher prevalence of the 30-bp LMP1 gene deletion, compared with studies of others. The unexpected finding of high incidence of 30-bp deletion in LMP1 gene in reactive lymphoid tissue and HD without EBV-positive Reed-Sternberg cells suggests that this deletion may not be relevant to HD pathogenesis in most cases. Copyright (C) 1997 by W.B. Saunders Company.

Cephalosporin C production by immobilized Cephalosporium acremonium cells in a repeated batch tower bioreactor

The industrial production of antibiotics with filamentous fungi is usually carried out in conventional aerated and agitated tank fermentors. Highly viscous non-Newtonian broths are produced and a compromise must be found between convenient shear stress and adequate oxygen transfer. In this work, cephalosporin C production by bioparticles of immobilized cells of Cephalosporium acremonium ATCC 48272 was studied in a repeated batch tower bioreactor as an alternative to the conventional process. Also, gas-liquid oxygen transfer volumetric coefficients, k(L)a, were determined at various air flow-rates and alumina contents in the bioparticle. The bioparticles were composed of calcium alginate (2.0% w/w), alumina (<44 micra), cells, and water. A model describing the cell growth, cephalosporin C production, oxygen, glucose, and sucrose consumption was proposed. To describe the radial variation of oxygen concentration within the pellet, the reaction-diffusion model forecasting a dead core bioparticle was adopted. The k(L)a measurements with gel beads prepared with 0.0, 1.0, 1.5, and 2.0% alumina showed that a higher k(L)a value is attained with 1.5 and 2.0%. An expression relating this coefficient to particle density, liquid density, and air velocity was obtained and further utilized in the simulation of the proposed model. Batch, followed by repeated batch experiments, were accomplished by draining the spent medium, washing with saline solution, and pouring fresh medium into the bioreactor. Results showed that glucose is consumed very quickly, within 24 h, followed by sucrose consumption and cephalosporin C production. Higher productivities were attained during the second batch, as cell concentration was already high, resulting in rapid glucose consumption and an early derepression of cephalosporin C synthesizing enzymes. The model incorporated this improvement predicting higher cephalosporin C productivity. (C) 2004 Wiley Periodicals, Inc.

MKK3/6-p38 MAPK negatively regulates murine MMP-13 gene expression induced by IL-1 beta and TNF-alpha in immortalized periodontal ligament fibroblasts

Matrix metalloprotease-13 (MMP-13) or collagenase-3 is involved in a number of pathologic processes such as tumor metastasis and angiogenesis, osteoarthritis, rheumatoid arthritis and periodontal diseases. These conditions are associated with extensive degradation of both connective tissue and bone. This report examines gene regulation mechanisms and signal transduction pathways involved in Mmp-13 expression induced by proinflammatory cytokines in periodontal ligament (PDL) fibroblasts. Mmp-13 mRNA expression was increased 10.7 and 9.5 fold after stimulation with IL-1 beta (5 ng/mL) and TNF-alpha (10 ng/mL), respectively. However, inhibition of p38 MAPKinase with SB203580 resulted in significant (p < 0.001) induction (23.2 and 18.1 fold, respectively) of Mmp-13 mRNA as assessed by real time PCR. Negative regulation of IL-1 induced Mmp-13 expression was confirmed by inhibiting p38 MAPK gene expression with siRNA. Transient transfection of dominant negative forms of MKK3 and MKK6 also resulted in increased levels of Mmp-13 mRNA after IL-1 beta stimulation. Mmp-13 mRNA expression induced by TNF-alpha was decreased by JNK and ERK inhibition. Western blot and zymogram analysis indicated that Mmp-13 protein expression induced by the proinflammatory cytokines were also upregulated by inhibition of p38 MAPK. Reporter gene experiments using stable cell lines harboring 660-bp sequence of the murine Mmp-13 proximal promoter indicated that transcriptional mechanisms were at least partially involved in this negative regulation of Mmp-13 expression by p38 MAPK and upstream MKK3/6. These results suggest a negative transcriptional regulatory mechanism mediated by p38 MAPK and upstream MKK3/6 on Mmp-13 expression induced by proinflammatory cytokines in PDL fibroblasts. (c) 2005 Elsevier B.V./International Society of Matrix Biology. All rights reserved.

Root surface conditioning with nicotine or cotinine reduces viability and density of fibroblasts in vitro

The purpose of study was to evaluate fibroblast attachment and cellular morphology on root surfaces chemically conditioned with nicotine or cotinine. A secondary objective was to determine if mechanical scaling and root planning of these chemically conditioned surfaces would alter cellular attachment. Root surface dentin specimens were prepared from uniradicular teeth of non-smoking patients. Specimens were randomly assigned to two experimental groups: no treatment (chemical conditioning only) and scaling and root planning after conditioning (SRPC). The concentrations of the tested substances were in the range of 0-1 mg/mL (nicotine) and 0-1 ?g/mL (cotinine). After a 24-h conditioning period, dentin slices were incubated with continuous lineage of fibroblastic cells from rat (McCoy cells) for another 24 h. Specimens were prepared for SEM analysis and microphotographs. The statistical analysis of the data indicated significant alteration of cellular morphology on fibroblasts that were grown on root surface exposed to nicotine concentrations greater than 1 ? g/mL. This effect of nicotine was not reduced by SRPC. on the other hand, in the SRPC group cellular density was greater. For cotinine-conditioned specimens, the greater concentrations also led to alteration on morphology, and these alterations were observed in the SRPC group as well. Cotinine did not induce significant changes on cellular density. The results indicated that fibroblasts are negatively influenced by nicotine present on the dentin substrate and also that scaling may reduce these effects. Cotinine treatment on root surfaces may alter cell morphology and density but these effects were less severe than that promoted by nicotine, and were not affected by scaling.

Epstein-Barr virus (EBV) nuclear antigen (EBNA)-4 mutation in EBV-associated malignancies in three different populations

Different ethnic groups with a high human leukocyte antigen (HLA)-A11 prevalence have been shown to experience a high rate of Epstein-Barr virus (EBV) infection, EBV-associated malignancies, and Epstein-Barr nuclear antigen (EBNA)-4 mutations. The epitopes 393-408 and 416-424 of EBNA-4 are major antigenic epitopes that elicit an HLA-A11 cytotoxic T lymphocyte (CTL) response to EBV infection. Mutations selectively involving one or more nucleotide residues in these epitopes affect the antigenicity of EBNA-4, because the mutant EBV strains are not recognized by the HLA-A11-restricted CTLs. To investigate these mutations in common EBV-associated malignancies occurring in different populations, we studied the mutation rate of epitopes 393-408 and 416-424 of EBNA-4 in 25 cases of EBV-associated Hodgkin's disease (HD), nine cases of AIDS-related non-Hodgkin's lymphoma, and 37 cases of EBV-associated gastric carcinoma (GC) from the United States, Brazil, and Japan. We found one or more mutations in these two epitopes in 50% (6/12) of United States HD, 15% (2/13) of Brazilian HD, 50% (6/12) United States GC and 28% (7/25) Japanese GC, and 22% (2/9) of United States AIDS-lymphoma. Similar mutations were found in 30% (3/10) of United States reactive, 0% (0/6) of Brazilian reactive, and 25% (2/8) Japanese reactive tissues. The most frequent amino acid substitutions were virtually identical to those seen in previously reported isolates from EBV-associated nasopharyngeal carcinomas and Burkitt's lymphomas occurring in high prevalence HLA-A11 regions. However, only 2/28 (7%) mutations occurred in HLA-A11-positive patients. Our studies suggest that: 1) EBNA-4 mutations are a common phenomenon in EBV-associated HD, GC, and AIDS-lymphoma; 2) the mutation rate does not vary in these geographic areas and ethnic groups; 3) EBNA-4 mutations in EBV-associated United States and Brazilian HD, United States and Japanese GC, and United States AIDS lymphomas are not related to patients' HLA-A11 status.

Prospective Evaluation of Laparoscopic Pancreatic Biopsies in 11 Healthy Cats

BackgroundDefinitive diagnosis of feline pancreatic disease is dependent on histologic examination of biopsies.HypothesisLaparoscopic punch biopsy of the pancreas does not significantly affect pancreatic health or clinical status of healthy cats, and provides an adequate biopsy sample for histopathology.AnimalsEleven healthy female domestic shorthair cats.MethodsEffects of laparoscopic pancreatic visualization alone in 5 cats compared with laparoscopic pancreatic visualization and punch biopsy in 6 cats were studied. Temperature, pulse, and respiratory rate, physical examination, and daily caloric intake were evaluated for 1 week before and 1 week after the procedure. Pain scores (simple descriptive score and dynamic interactive visual assessment score) were evaluated hourly during the 1st 6 hours postprocedure. Complete blood cell counts, serum biochemical profiles, serum feline pancreatic lipase immunoreactivity, and urine specific gravity were evaluated before the procedure and at 6, 24, and 72 hours postprocedure. One month postprocedure, during sterilization, the pancreas was reassessed visually in all cats, and microscopically in the biopsy group.ResultsFor all variables evaluated, there were no significant differences between biopsy and control cats. Re-evaluation of the pancreatic biopsy site 1 month later documented a normal tissue response to biopsy. The laparoscopic punch biopsy forceps provided high-quality pancreatic biopsy samples with an average size of 5 mm x 4 mm on 2-dimensional cut section.Conclusions and Clinical ImportanceLaparoscopic pancreatic biopsy is a useful and safe technique in healthy cats.

Rhamnolipid production by Pseudomonas aeruginosa LBI growing on soapstock as the sole carbon source

A new bacterial strain, was isolated from petroleum contaminated soil, identified and named Pseudomonas aeruginosa strain LBI. The new strain produced surface-active rhamnolipids by batch cultivation in a mineral salts medium with soapstock as the sole carbon source. Biosurfactant production increased after nitrogen depletion. The maximum rhamnolipid concentration, 15.9 g/l, was reached when it was incubated in a bioreactor with a constant K(L)a of 169.9 h(-1). (C) 2002 Elsevier B.V. Ltd. All rights reserved.

Impact strength of denture base and reline acrylic resins subjected to long-term water immersion

Water may influence the mechanical properties of the acrylic resins. Thus, the effect of water storage on the impact strength (IS) of one denture base (Lucitone 550 - L) and four reline resins (Tokuyama Rebase II - T; UfiGel Hard - U; Kooliner - K; New Truliner - NT) was evaluated. Bars of L were made (60 x 6 x 2 mm) and relined (2 mm) with T, U, K, NT and L. Intact specimens of each material (60 x 6 x 4 mm) were also fabricated for comparative purposes. Specimens were submitted to Charpy impact tests without water storage (control) and after immersion in water for 7, 90 and 180 days. Data (kJ/m 2) analyzed by two-way ANOVA and Tukey's test (p=0.05) revealed that after 90 days, U exhibited an increase in the IS (0.93) compared to 7 days (0.58). K (1.48) and L/K (7.21) exhibited a decrease at the 7-day period (1.01 and 3.23, respectively). NT (0.60) showed an increase in the IS after 180 days (1.52), whereas L/ NT (7.70) showed a decrease (3.17). Water immersion improved the IS of U and NT, and decreased the IS of K, L/K, and L/NT. Water may affect differently the IS of acrylic resins and, consequently, the resistance to fracture of relined denture bases.

Zeros de Polinômios Perturbados

Pós-graduação em Matematica Aplicada e Computacional - FCT

Caracterização da cobertura vegetal na equação universal de perda de solos (fator C) por meio de geotecnologias

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)