Wannier functions of isolated bands in one-dimensional crystals

We present a simple procedure to obtain the maximally localized Wannier function of isolated bands in one-dimensional crystals with or without inversion symmetry. First, we discuss the generality of dealing with real Wannier functions. Next, we use a transfer-matrix technique to obtain nonoptimal Bloch functions which are analytic in the wave number. This produces two classes of real Wannier functions. Then, the minimization of the variance of the Wannier functions is performed, by using the antiderivative of the Berry connection. In the case of centrosymmetric crystals, this procedure leads to the Wannier-Kohn functions. The asymptotic behavior of the Wannier functions is also analyzed. The maximally localized Wannier functions show the expected exponential and power-law decays. Instead, nonoptimal Wannier functions may show reduced exponential and anisotropic power-law decays. The theory is illustrated with numerical calculations of Wannier functions for conduction electrons in semiconductor superlattices.

Evaluation of the performance of a castor-oil based formulation in limiting pesticide residues in strawberry crops

A study was made to evaluate the effect of a castor oil-based detergent on strawberry crops treated with different classes of pesticides, namely deltamethrin, folpet, tebuconazole, abamectin and mancozeb, in a controlled environment. Experimental crops of greenhouse strawberries were cultivated in five different ways with control groups using pesticides and castor oil-based detergent. The results showed that the group 2, which was treated with castor oil-based detergent, presented the lowest amount of pesticide residues and the highest quality of fruit produced.

Risk factors for recovery of Imipenem-or ceftazidime-resistant Pseudomonas aeruginosa among patients admitted to a teaching hospital in Brazil

background. The prevalence of resistance to imipenem and ceftazidime among Pseudomonas aeruginosa isolates is increasing worldwide.objective. Risk factors for nosocomial recovery ( defined as the finding of culture- positive isolates after hospital admission) of imipenemresistant P. aeruginosa ( IRPA) and ceftazidime- resistant P. aeruginosa ( CRPA) were determined.design. Two separate case- control studies were conducted. Control subjects were matched to case patients ( ratio, 2: 1) on the basis of admission to the same ward at the same time as the case patient. Variables investigated included demographic characteristics, comorbid conditions, and the classes of antimicrobials used.setting. The study was conducted in a 400- bed general teaching hospital in Campinas, Brazil that has 14,500 admissions per year. Case patients and control subjects were selected from persons who were admitted to the hospital during 1992 - 2002.results. IRPA and CRPA isolates were obtained from 108 and 55 patients, respectively. Statistically significant risk factors for acquisition of IRPA were previous admission to another hospital ( odds ratio [ OR], 4.21 [ 95% confidence interval {CI}, 1.40- 12.66];), hemodialysis Pp. 01 ( OR, 7.79 [ 95% CI, 1.59- 38.16];), and therapy with imipenem ( OR, 18.51 [ 95% CI, 6.30- 54.43];), amikacin ( OR, 3.22 Pp. 01 P !.001 [ 95% CI, 1.40- 7.41];), and/ or vancomycin ( OR, 2.48 [ 95% CI, 1.08- 5.64];). Risk factors for recovery of CRPA were Pp. 005 Pp. 03 previous admission to another hospital ( OR, 18.69 [ 95% CI, 2.00- 174.28];) and amikacin use ( OR, 3.69 [ 95% CI, 1.32- 10.35]; Pp. 01). Pp. 01conclusion. Our study suggests a definite role for several classes of antimicrobials as risk factors for recovery of IRPA but not for recovery of CRPA. Limiting the use of only imipenem and ceftazidime may not be a wise strategy to contain the spread of resistant P. aeruginosa strains.

Expression of fibroblast growth factor-8 and its cognate receptors, fibroblast growth factor receptor (FGFR)-3c and-4, in fetal bovine preantral follicles

Paracrine cell signaling is thought to be important for ovarian follicle development, and a role for some members of the fibroblast growth factor (FGF) family have been suggested. In the present study, we tested the hypothesis that FGF-8 and its cognate receptors (FGFR-3c and FGFR-4) are expressed in bovine preantral follicles. Reverse transcription-polymerase chain reaction was used to amplify bovine FGF-8, FGFR-3c, and FGFR-4 from preantral follicle samples and a variety of fetal and adult tissues. All three genes were widely expressed in fetal tissues, with a restricted expression pattern in adult tissues. FGF-8 and FGFR-3c were expressed in secondary follicles in 70% of fetuses examined, whereas FGFR-4 expression was significantly less frequent (20%). FGFR-3c expression frequency was significantly lower in primordial compared to secondary follicles, and FGF-8 expression showed a similar trend. FGFR-4 was only observed when all follicle classes of an individual were expressing both FGF-8 and FGFR-3c. We conclude that FGF-8 and its receptors are expressed in preantral follicles in a developmentally regulated manner. (C) 2005 Wiley-Liss, Inc.

Antiulcerogenic and analgesic effects of Maytenus aquifolium, Sorocea bomplandii and Zolernia ilicifolia

Maytenus aquifolium (Celastraceae), Sorocea bomplandii (Moraceae) and Zolernia ilicifolia (Fabaceae) are native plants from the Tropical Atlantic Forest (Mata Atlantica, Brazil) known a 'espinheira-santa'. These plants are traditionally used as analgesic and antiulcerogenic medicine, with the same traditional uses of the true 'espinheira-santa' (Maytenus ilicifolia, Celastraceae), an efficient antiulcerogenic agent. Pharmacological and toxicological studies with these plants have not been carried out. The purpose in this study was to evaluate the efficacy (analgesic and antiulcerogenic activities), safety (acute toxicity) and quality (phytochemical profile) of these three plants. The analgesic effect was analyzed by writhing and tail flick tests, while anti Ulcerogenic effect was performed through ulcer induction by ethanol and indomethacin/bethanecol assays. LD., and acute toxic effects, as well as phytochemical profiles of all plants also were carried. Surprisingly, the three plants showed analgesic and antiulcerogenic effects at dose of 1000 mg/kg, v.o. Maytenus aquifolium lowering all ulcerogenic parameters (ethanol test), but increased the ulcerogenic effects in the indoniethacin/bethanecol test. Sorocea bomplandii produced antiulcerogenic effects in both experimental models used, while Zolernia ilicifolia showed significant effects only in indomethacin/bethanecol-induced gastric lesions. Pre-treatment with Zolernia ilicifolia induced someone toxic effects, A phytochemical profile for each plant species was determined and its main chemical classes of compounds were described. (C) 2001 Elsevier B.V. Ireland Ltd. All rights reserved.

Discrimination of bile acids by the rainbow trout olfactory system: evidence as potential pheromone

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

Determination of toxigenic capacity by reverse transcription polymerase chain reaction in coagulase-negative staphylococci and Staphylococcus aureus isolated from newborns in Brazil

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

Chemomodulation of human dendritic cell function by antineoplastic agents in low noncytotoxic concentrations

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Cytogenetic analysis of A- and B-chromosomes of Prochilodus lineatus (Teleostei, Prochilodontidae) using different restriction enzyme banding and staining methods

Different cytogenetic techniques were used to analyse the chromosomes of Prochilodus lineatus with the main objective of comparing the base composition of A- and B-chromosomes. The results of digestion of chromosomes with 10 different restriction endonucleases (REs), silver staining, CMA(3) staining and C-banding indicated the existence of different classes of highly repetitive DNA in the A-set and also suggested the existence of compositional differences between the chromatin of A- and B-chromosomes. The 5-BrdU incorporation technique showed a late replicating pattern in all B-chromosomes and in some heterochromatic pericentromeric regions of A-chromosomes. The cleavage with RE BamHI produced a band pattern in all chromosomes of P. lineatus which permitted the tentative pairing of homologues in the karyotype of this species. We concluded that the combined use of the above techniques can contribute to the correct identification of chromosomes and the karyotypic analysis in fishes. on the basis of the results, some aspects of chromosome structure and the origin of the B-chromosomes in P. lineatus are discussed.

Dynamics of 5S rDNA in the tilapia (Oreochromis niloticus) genome: repeat units, inverted sequences, pseudogenes and chromosome loci

In higher eukaryotes, the 5S ribosomal DNA (5S rDNA) is organized in tandem arrays with repeat units composed of a coding region and a non-transcribed spacer sequence (NTS). These tandem arrays can be found on either one or more chromosome pairs. 5S rDNA copies from the tilapia fish. Oreochromis niloticus, were cloned and the nucleotide sequences of the coding region and of the non-transcribed spacer were deter-mined. Moreover, the genomic organization of the 5S rDNA tandem repeats was investigated by fluorescence in situ hybridization (FISH) and Southern blot hybridization. Two 5S rDNA classes, one consisting of 1.4-kb repeats and another one with 0.5-kb repeats were identified and designated 5S rDNA type I and type II, respectively, An inverted 5S rRNA gene and a 5S rRNA putative pseudogene were also identified inside the tandem repeats of 5S rDNA type I. FISH permitted the visualization of the 5S rRNA genes at three chromosome loci, one of them consisting of arrays of the 5S rDNA type I, and the two others corresponding to arrays of the 5S rDNA type II. The two classes of the 5S rDNA. The presence of pseudogenes, and the inverted genes observed in the O. niloticus genome might be a consequence of the intense dynamics of the evolution of these tandem repeat elements. Copyright (C) 2002 S. Karger AG, Basel.

Genomic organization of repetitive DNAs in the cichlid fish Astronotus ocellatus

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

Differentiation of the XY Sex Chromosomes in the Fish Hoplias malabaricus (Characiformes, Erythrinidae): Unusual Accumulation of Repetitive Sequences on the X Chromosome

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

Molecular organization of 5S rDNA in sharks of the genus Rhizoprionodon: insights into the evolutionary dynamics of 5S rDNA in vertebrate genomes

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

Reproductive biology of the rock shrimp Sicyonia dorsalis (Decapoda: Penaeoidea) from the southeastern coast of Brazil

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

Cytochemistry of fat body trophocytes and ovaries of workers and queens of Melipona quadrifasciata anthidioides (Hymenoptera: Apidae: Meliponini) during vitellogenesis

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