The influence of area/volume ratio on microstructure and non-Ohmic properties of SnO2-based varistor ceramic blocks

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

Cell blocks allow reliable evaluation of expression of basal (CK5/6) and luminal (CK8/18) cytokeratins and smooth muscle actin (SMA) in breast carcinoma

Objective:Gene expression studies have revealed several molecular subtypes of breast carcinoma with distinct clinical and biological behaviours. DNA microarray studies correlated with immunohistochemical profiling of breast carcinomas using cytokeratin (CK) markers, Her2/neu, oestrogen receptor (ER), and basal myoepithelial cell markers have identified five breast tumour subtypes: (i) luminal A (ER+; Her2/neu-), (ii) luminal B (ER+; Her2/neu+), (iii) Her2 overexpression (ER-; Her2/neu+), (iv) basal-like (ER-; Her2/neu-, CK5/6 and 14+), and (v) negative for all markers. Luminal carcinomas express cytokeratins in a luminal pattern (CK8/18), and the basal-like type expresses CK5/6 and CK14 or basal epithelial cell markers. CK5/6, CK8/18, and smooth muscle actin (SMA) expression were assessed in cell blocks and compared with expression in surgical specimens.Methods:Sixty-two cases of breast carcinoma diagnosed by fine needle aspiration cytology with cell blocks and available surgical specimens were included. Cell blocks containing at least 10 high-power fields each with at least 10 tumour cells and surgical specimens were immunostained for CK5/6, CK8/18 and SMA.Results:Percentage sensitivity, specificity, positive predictive value, negative predictive value and accuracy were, respectively, 77, 100, 100, 92 and 94 for CK5/6; 98, 66, 96, 80 and 95 for CK8/18; and 92, 96, 85, 98 and 95 for SMA.Conclusion:The identification of CK5/6, CK8/18 and SMA by immunohistochemistry in cell blocks can be a reliable method that yields results close to those obtained in surgical specimens, and can contribute to the classification of breast carcinomas with luminal and basal expression patterns, providing helpful information in the choice of treatment and in the evaluation of prognostic and predictive factors.

Leishmune (R) vaccine blocks the transmission of canine visceral leishmaniasis - Absence of Leishmania parasites in blood, skin and lymph nodes of vaccinated exposed dogs

Leishmune (R) vaccine is the first licensed vaccine against canine visceral leishmaniasis. It contains the Fucose-Mannose-ligand (FML) antigen of Leishmania donovani. The potential Leishmune (R) vaccine effect on the interruption of the transmission of the disease, was assayed by monitoring, in untreated (n = 40) and vaccinated dogs (n = 32) of a Brazilian epidemic area: the kala-azar clinical signs, the FML-seropositivity and the Leishmania parasite evidence by immunohistochemistry of skin and PCR for Leishmanial DNA of lymph node and blood samples. on month I I after vaccination, untreated controls showed: 25% of symptomatic cases, 50% of FML-seropositivity, 56.7% of lymph node PCR, 15.7% of blood PCR and 25% of immunohistochemical positive reactions. The Leishmune (R)-vaccinated dogs showed 100% of seropositivity to FML and a complete absence of clinical signs and of parasites (0%) in skin, lymph node and blood PCR samples (P < 0.01). The positivity in FML-ELISA in untreated dogs significantly correlates with the PCR in lymph node samples (p < 0.001) and with the increase in number of symptoms (p = 0.006) being strong markers of infectiousness. The absence of symptoms and of evidence of Leishmania DNA and parasites in Leishmune (R)-vaccinated animals indicates the non-infectious condition of the Leishmune (R)-vaccinated dogs. (c) 2005 Elsevier Ltd. All rights reserved.

An algorithm for arranging response surface designs in small blocks

We consider the problem of blocking response surface designs when the block sizes are prespecified to control variation efficiently and the treatment set is chosen independently of the block structure. We show how the loss of information due to blocking is related to scores defined by Mead and present an interchange algorithm based on scores to improve a given blocked design. Examples illustrating the performance of the algorithm are given and some comparisons with other designs are made. (C) 2000 Elsevier B.V. B.V. All rights reserved.

Evidence of room temperature charge-density wave behavior and glass-like states in pressed pellets of lightly doped poly (3-methyl thiophene)

We show room temperature charge-density wave (CDW) characteristics in d.c. and a.c. electric data in pressed pellets of lightly doped poly(3-methylthiophene). The possibility of a Peierls glass is discussed and metastables states are observed. D.C. and A.C. data also show a state with negative differencial resistance.

Room temperature ferromagnetic behavior in pressed pellets of doped poly (3-methylthiophene)

Room temperature ferromagnetic behavior has been observed in pressed pellets of doped poly(3-methylthiophene). In this work we show that thermoremance data taken in two different ways favours the interpretation of data in terms of the Dzialoshinski-Moriya anisotropic superexchange interaction of the polarons via dopant anions giving rise to weak ferromagnetism.

Physiological responses of pressed baker's yeast cells pre-treated with citric, malic and succinic acids

The dough-leavening power of baker's yeast, Saccharomyces cerevisiae, is strongly influenced by conditions under which the pressed yeast is maintained prior to bread dough preparation. In this study, the influence of the yeast cell's pre-treatment with organic acids (malic, succinic, and citric acids) was investigated at a wide range of pH values when the pressed yeast samples were exposed to 30 degrees C. Increased fermentative activity was observed immediately after pre-treatment of the cells with organic acids. When the pH of the pressed yeast containing added citric acid was raised from 3.5 to 7.5, increases in both fermentative and maltase activities were obtained. Improvements in viability and levels of total protein were also observed during storage in the presence of citric acid, notably at pH 7.5. Glycerol-3-phosphate dehydrogenase activity and levels of internal glycerol also increased in the presence of citrate. on the other hand, pressed yeast samples containing succinic acid at pH 7.5 showed decreased viability during storage despite the maintenance of high levels of fermentative activity, similar to pressed yeast containing malic acid at pH 4.5 and 7.5. Decreases in intracellular levels of trehalose were observed during storage in all cases. Overall, the results of this study revealed the potential benefits of adding organic acids to pressed yeast preparations for baking purposes.

GIGAHERTZ CONDUCTIVITY OF PRESSED PELLETS OF CLO4--DOPED POLY(3-METHYLTHIOPHENE) OBTAINED FROM ELECTRON-SPIN-RESONANCE MEASUREMENTS

Gigahertz conductivity of pressed pellets of ClO4--doped poly( 3-methylthiophene) can be readily obtained from the asymmetry ratio (A / B) of the electron spin resonance line using Dyson's theory. The measurements were performed in three different frequencies, 1.3, 9.4, and 35 GHz. The temperature dependence of the gigahertz conductivity is sensitive to the heating rate, probably due to the ordering of the randomly assembled anions. (C) 1994 Academic Press, Inc.

Losartan (DUP-753) blocks the natriuretic, kaliuretic and antidiuretic effect of intracerebroventricular injection of carbachol in water-loaded rats

We determined the effect of intracerebroventricular (icv) administration of losartan, an angiotensin II (ANG II) subtype 1 receptor (AT1) antagonist, on icv carbachol-induced natriuresis, kaliuresis and antidiuresis in water-loaded male Holtzman rats (250-300 g) with a cannula implanted into the lateral ventricle (LV). The rats were water loaded with 5% of their body weight by gavage twice, with the second gavage one hour after the first. Carbachol (2 nmol in 1 mu l) was injected icv immediately after the second load. When losartan (DUP-753, 50 nmol in 1 mu l) was administered icv, it was given 3 min before carbachol. Previous icv treatment with losartan significantly reduced the icv carbachol-induced natriuresis (324 +/- 17 mu Eq/120 min), kaliuresis (103 +/- 15 mu Eq/120 min) and antidiuresis (13.5 +/- 2.1 ml/120 min) compared to the effects of previous icv injection of saline (Nai excretion = 498 +/- 22 mu Eq/120 min; K+ excretion = 167 +/- 20 mu Eq/120 min; urine volume = 5.2 +/- 1.2 ml/120 min). These results, reported as means +/- SEM for 12 rats in each group, are consistent with the hypothesis that AT1 subtype receptors participate in the regulation of body electrolyte balance.

Field-dependent conductivity at low electric fields in pressed pellets of doped poly (3-methylthiophene): evidence of charge-density wave depinning

Field-dependent conductivity at low electric fields was observed from low to room temperature in pressed pellets of doped poly(3-methylthiophene). The room temperature data showed good agreement with Bardeen's theory of charge-density wave depinning and the values of the parameters obtained are consistent with a strong electron-phonon interaction as expected for quasi-one dimensional systems. (C) 2003 Elsevier B.V. Ltd. All rights reserved.

CHEMICAL SYMPATHECTOMY BLOCKS ANDROGEN BIOSYNTHESIS DURING PREPUBERTY

Twenty-one-day old male Wistar rats were injected subcutaneously with guanethidine (GUA) at doses of 5 and 10 mg kg(-1) day(-1) for 20 days. Animals were sacrificed by decapitation during the prepubertal (41 days of age) and early-pubertal (51 days of age) periods of sexual development. The testes were collected, frozen in liquid N-2 and stored at -70 degrees C until determination of testicular progesterone (P): androstenedione (A) and testosterone (T). Higher levels of P (2.18 +/- 0.24 ng/g. control = 1.24 +/- 0.16 ng/g) associated with decreased levels of androgens (A = 0.26 +/- 0.06 ng/g and T = 2.05 +/- 0.19 ng/g; control = 1.86 +/- 0.76 ng/g and 8.48 +/- 1.16 ng/g, respectively) were observed in 10 mg GUA-treated rats of prepubertal age, while only P levels (3.12 +/- 0.51 ng/g control = 1.73 +/- 0.27 ng/g) were increased in rats of early pubertal age. It is important to note that in 41-day old male rats both 5 and 10 mg were effective in decreasing testicular concentration of testosterone. These results suggest that the sympathetic innervation of the testis is involved in the modulation of androgen biosynthesis, acting through a selective step in the steroid biochemical pathway during the pubertal process and that under the conditions employed the blockage in androgen biosynthesis in the prepubertal stage of sexual maturation is dependent on the dose of GUA.

THERMAL-HISTORY-DEPENDENT TRANSITION IN PRESSED PELLETS OF CLO4(-)-DOPED POLY(3-METHYLTHIOPHENE)

Electron-spin-resonance and dc conductivity data show a thermal-history-dependent transition at 240 K in pressed pellets of ClO4--doped poly(3-methylthiophene) (P3MT). We discuss the possibility of this transition to be a Peierls transition from a room-temperature-metallic to a charge-density-wave state driven by anions ordering at this temperature. Below 100 K, dc conductivity shows a change from linear to exponential decay. Nonlinear conductivity has also been observed in this system for very low electric fields.

Hot-pressed 9.5/65/35 PLZT prepared by the polymeric precursor method

A 9.5/65/35 PLZT ceramic with a Pb-0.905 La-0.095 (Zr-0.65 Ti-0.35)(0.976) O-3 + 35 w% PbO formula was prepared using the Pechini method for powder preparation and two-step sintering in an oxygen atmosphere. Thr first step consisted of sintering at 1200 degrees C for 4 h with slow heating and cooling rates. The second step consisted of hot pressing at 1200 degrees C for 3 h, with slow heating and cooling rates and pressing pressures of 20 MPa (initial pressure) and 40 MPa (at sintering temperature). Investigations were made of the powder phase formation and powder morphology, i.e. The structure of sintered and hot-pressed PLZT ceramics. SEM microstructural analyses were carried out on the sintering and hot-pressing processes. (C) 2000 Elsevier B.V. Ltd and Techna S.r.l. All rights reserved.