Effect of Ti and C additions on structural and magnetic properties of (Pr,Nd)-Fe-B nanocrystalline magnetic materials

Effects of titanium carbide (TiC) addition on structural and magnetic properties of isotropic (Pr,Nd)-Fe-B nanocrystalline magnetic materials have been investigated. In this work, we investigate the effect of TiC addition on a (Pr,Nd)-poor and B-rich composition, as well as on a B-poor and (Nd, Pr)-rich composition. Rapidly solidified (Pr, Nd)-Fe-B alloys were prepared by melt-spinning. The compositions studied were (Pr(1-x)Nd(x))(4)Fe(78)B(18) (x = 0, 0.5, and 1) with addition of 3 at% TiC. Unlike the (Pr(x)Nd(1-x))(9.5)Fe(84.5)B(6) materials that present excellent values for coercive. field and energy product, the (Pr,Nd)-poor and B-rich composition alloys with TiC addition present lower values. Rietveld analysis of X-ray data and Mossbauer spectroscopy revealed that samples are predominantly composed of Fe(3)B and alpha-Fe. For the RE-rich compositions (Pr(x)Nd(1-x))(9.5)Fe(84.5)B(6) (x = 0.1, 0.25, 0.5, 0.75, and 1) with the addition of 3 at% TiC, the highest coercive field and energy product (8.4 kOe and 14.4 MGOe, respectively) were obtained for the composition Pr(9.5)Fe(84.5)B(6). (c) 2008 Elsevier B.V. All rights reserved.

Silicon Field-Emission Devices Fabricated Using the Hydrogen Implantation-Porous Silicon (HI-PS) Micromachining Technique

This paper presents a relatively simple method to fabricate field-emitter arrays from silicon substrates. These devices are obtained from silicon micromachining by means of the HI-PS technique-a combination of hydrogen ion implantation and porous silicon used as sacrificial layer. Also, a new process sequence is proposed and implemented to fabricate self-aligned integrated field-emission devices based on this technique. Electrical characteristics of the microtips obtained show good agreement with the Fowler-Nordheim theory, which are suitable for the proposed application.

Effect of Calcium on the in vitro Growth of Aechmea blanchetiana (Baker) L. B. Smith Plantlets

This work investigated the influence of different concentrations of calcium on the growth of plantlets of the bromeliad Aechmea blanchetiana cultured in vitro. Seedlings of A. blanchetiana were axenically cultured in liquid Murashige and Skoog basal medium supplemented with different concentrations of calcium (Ca; 1.5, 3, 4.5, 6, or 12 mM) without growth regulators. The resulting plantlets were cultured under 93 mol m-2 s-1 illumination, 12 hour photoperiod regime and 25C 1 for 120 days with subculture to fresh identical media every 30 days. The addition of calcium at 9.38 mM to MS modified medium increased the production of fresh and dry mass of plantlets, whilst chlorine from calcium chloride dehydrate (CaCl2 2 H2O) in excess (3.35 mM) decreased both the fresh and dry mass of plantlets.

Molecular Identification and Phylogenetic Analysis of a Group 16SrI-B Phytoplasma Associated with Sugarcane Yellow Leaf Syndrome in Brazil

Yellow leaf syndrome was a serious problem in the beginning of the 1990s in Brazil, when yield losses were estimated to be around 50%. The disease is currently endemic, but it is considered potentially important. Previous studies have revealed only the presence of a luteovirus associated with the disease in Brazil. We report that a phytoplasma of 16SrI-B is also associated with this disease. This is the first demonstration of the presence of a group 16SrI-B phytoplasma in association with sugarcane yellow leaf in Brazil.

Persistent and remodeling hepatic preneoplastic lesions present differences in cell proliferation and apoptosis, as well as in p53, BcI-2 and NF-kappa B pathways

During rat hepatocarcinogenesis preneoplastic lesions (PNL) emerge which may persist (pPNL) and be sites of progress to cancer or suffer remodeling (rPNL) tending to disappear. Cellular and molecular mechanisms involved in both phenotypes are not sufficiently elucidated. pPNL and rPNL cellular proliferation and apoptosis were evaluated in rats submitted to the resistant hepatocyte (RH) model, and an adjusted growth index (AGI) was established. p53, Bcl-2, and NF-kappa B p65 subunit expression was evaluated by immunohistochemistry in pPNL and rPNL. p65 expression and NF-kappa B activation was evaluated by Western blot assays in whole livers. A lower number of BrdU-stained hepatocyte nuclei/mm(2) and higher number of apoptotic bodies (AB) per mm(2) were observed in remodeling compared to pPNL. Cytoplasmic p53 accumulation is related to increased hepatocarcinoma malignancy. We observed that 71.3% pPNL and 25.4% rPNL (P < 0.05) presented p53 staining in the cytoplasm. Similarly, 67.7% pPNL and 23.1 % rPNL (P < 0.05) presented increased Bcl-2 staining. Thirty-two percent pPNL and 15.6% rPNL (P < 0.05) presented p65 staining. Compared to normal rats, increase (P < 0.05) of hepatic p65 expression and NF-kappa B activation in rats submitted to the RH model was observed. in agreement to previous studies hepatic pPNL and rPNL differ regarding cell proliferation and apoptosis. Moreover, persistence and remodeling involve differences in p53, Bcl-2, and NF-kappa B pathways. These data point to molecular pathways that may direct preneoplastic lesions to spontaneously regress or to progress to cancer.

Enhanced fibroblast adhesion and proliferation on electrospun fibers obtained from poly(isosorbide succinate-b-L-lactide) block copolymers

Block copolymers containing isosorbide succinate and L-lactic acid repeating units with different mass compositions were synthesized in two steps: bulk ring-opening copolymerization from L-lactide and poli(isosorbide succinate) (PIS) preoligomer, in the presence of tin(II) 2-ethylhexanoate as catalyst. followed by chain extension in solution by using hexamethylene diisocyanate. Poly(L-lactide) (PLLA) and a chain extension product from PIS were also obtained, for comparison. SEC, (1)H and (13)C NMR, MALDI-TOFMS, WAXD, DSC, TG, and contact angle measurements were used in their characterization. The incorporation of isosorbide succinate into PLLA main backbone had minor effect on the thermal stability and the T(g) of the products. However, it reduced the crystallinity and increased the surface energy in relation to PLLA. Nonwoven mats of the block copolymers and PLLA obtained by electrospinning technique were submitted to fibroblasts 3T3-L1 cell culture. The copolymers presented enhanced cell adhesion and proliferation rate as revealed by MTT assay and SEM images. (C) 2009 Elsevier Ltd. All rights reserved.

Peptidase activities in the semen from the ductus deferens and uterus of the neotropical rattlesnake Crotalus durissus terrificus

To understand the role of peptidases in seminal physiology of Crotalus durissus terrificus, intra- and inter-seasonal activity levels of acid (APA), basic (APB), puromycin-sensitive (APN-PS) and puromycin-insensitive neutral (APN-PI), cystyl (CAP), dipeptidyl-IV (DPPIV), type-1 pyroglutamyl (PAP-I) and prolyl-imino (PIP) aminopeptidases as well as prolyl endopeptidase (POP) were evaluated in soluble (SF) and/or membrane-bound (MF) fractions of semen collected from the ductus deferens of the male reproductive tract and from the posterior portion of the uterus. Seminal APB, PIP and POP were detected in SF, while other peptidases were detected in SF and MF. Only the convoluted posterior uterus in winter and autumn had semen. Relative to other examined peptidases, in general, APN-PI, APN-PS and APB activities were predominant in the semen from the uterus and throughout the year in the semen from the ductus deferens, suggesting their great relevance in the seminal physiology of C. d. terrificus. The levels of peptidase activities in the ductus deferens semen varied seasonally and were different from those of semen in the uterus, suggesting that their modulatory actions on susceptible peptides are integrated to the male reproductive cycle events and spermatozoa viability of this snake.

B-1 cells modulate oral tolerance in mice

Although the origin and functions of B-1 cells are controversial, they are considered as a cellular element of innate immunity due to their ability to produce natural autoantibodies of the IgM type. These antibodies are encoded by a relatively limited repertoire of V genes, and their resulting diversity is smaller than that produced by conventional B cells. B-1 cells constitute the larger fraction of B cells in the peritoneal cavity and migrate to non-specific inflammation sites. In addition, they contribute to the production of IgA antibodies in the intestinal lamina propria. It has been demonstrated that they participate in the induction and maintenance of peripheral tolerance. Herein, the participation of B-1 cells in inducing oral tolerance is evaluated. Unexpectedly, BALB/Xid mice, the animals deficient in B-1 cells, are not tolerized to OVA but instead are responsive to oral immunization. Conversely, BALB/c mice respond to oral tolerance to this antigen. We used these biological characteristics of these animals to investigate whether BA cells are involved in the induction of oral tolerance to OVA. Results show that B-1 cells from BALB/c mice, treated orally with OVA and adoptively transferred to BALB/Xid mice were able to suppress local hypersensitivity reaction and lymphoproliferative cellular response observed in BALB/.Xid mice. These data demonstrate that B-1 cells have regulatory properties and are involved in the induction of oral tolerance. (C) 2009 Elsevier B.V. All rights reserved.

Optimization of preservative system in ophthalmic suspension with dexamethasone and polymyxin B

A simplex-lattice statistical project was employed to study an optimization method for a preservative system in an ophthalmic suspension of dexametasone and polymyxin B. The assay matrix generated 17 formulas which were differentiated by the preservatives and EDTA (disodium ethylene diamine-tetraacetate), being the independent variable: X-1 = chlorhexidine digluconate (0.010 % w/v); X-2 = phenylethanol (0.500 % w/v); X-3 = EDTA (0.100 % w/v). The dependent variable was the Dvalue obtained from the microbial challenge of the formulas and calculated when the microbial killing process was modeled by an exponential function. The analysis of the dependent variable, performed using the software Design Expert/W, originated cubic equations with terms derived from stepwise adjustment method for the challenging microorganisms: Pseudomonas aeruginosa, Burkholderia cepacia, Staphylococcus aureus, Candida albicans and Aspergillus niger. Besides the mathematical expressions, the response surfaces and the contour graphics were obtained for each assay. The contour graphs obtained were overlaid in order to permit the identification of a region containing the most adequate formulas (graphic strategy), having as representatives: X-1 = 0.10 ( 0.001 % w/v); X-2 = 0.80 (0.400 % w/v); X-3 = 0.10 (0.010 % w/v). Additionally, in order to minimize responses (Dvalue), a numerical strategy corresponding to the use of the desirability function was used, which resulted in the following independent variables combinations: X-1 = 0.25 (0.0025 % w/v); X-2 = 0.75 (0.375 % w/v); X-3 = 0. These formulas, derived from the two strategies (graphic and numerical), were submitted to microbial challenge, and the experimental Dvalue obtained was compared to the theoretical Dvalue calculated from the cubic equation. Both Dvalues were similar to all the assays except that related to Staphylococcus aureus. This microorganism, as well as Pseudomonas aeruginosa, presented intense susceptibility to the formulas independently from the preservative and EDTA concentrations. Both formulas derived from graphic and numerical strategies attained the recommended criteria adopted by the official method. It was concluded that the model proposed allowed the optimization of the formulas in their preservation aspect.

Structured lipids obtained by chemical interesterification of olive oil and palm stearin

Interesterification of palm stearin (PS) with liquid vegetable oils could yield a good solid fat stock that may impart desirable physical properties, because PS is a useful source of vegetable hard fat, providing beta` stable solid fats Dietary ingestion of olive oil (OO) has been reported to have physiological benefits such as lowering serum cholesterol levels Fat blends, formulated by binary blends of palm stearin and olive oil in different ratios, were subjected to chemical interesterification with sodium methoxide The original and interesterified blends were examined for fatty acid and triacylglycerol composition, melting point, solid fat content (SFC) and consistency. Interestenfication caused rearrangement of triacylglycerol species, reduction of trisaturated and triunsaturated triacylglycerols content and increase in diunsaturated-monosaturated triacylglycerols of all blends, resulting in lowering of melting point and solid fat content The incorporation of OO to PS reduced consistency, producing more plastic blends The mixture and chemical interesterification allowed obtaining fats with various degrees of plasticity, increasing the possibilities for the commercial use of palm stearin and olive oil (C) 2009 Elsevier Ltd All rights reserved

In vitro studies of cutaneous retention of magnetic nanoemulsion loaded with zinc phthalocyanine for synergic use in skin cancer treatment

In this study was developed a new nano drug delivery system (NDDS) based on association of biodegradable surfactants with biocompatible magnetic fluid of maguemita citrate derivative. This formulation consists in a magnetic emulsion with nanostructured colloidal particles. Preliminary in vitro experiments showed that the formulation presents a great potential for synergic application in the topical release of photosensitizer drug (PS) and excellent target tissue properties in the photodynamic therapy (PDT) combined with hyperthermia (HPT) protocols. The physical chemistry characterization and in vitro assays were carried out by Zn(II) Phtalocyanine (ZnPc) photosensitizer incorporated into NDDS in the absence and the presence of magnetic fluid, showed good results and high biocompatibility. In vitro experiments were accomplished by tape-stripping protocols for quanti. cation of drug association with different skin tissue layers. This technique is a classical method for analyses of drug release in stratum corneum and epidermis+ dermis skin layers. The NDDS formulations were applied directly in pig skin (tissue model) fixed in the cell`s Franz device with receptor medium container with a PBS/EtOH 20% solution (10mM, pH 7.4) at 37 degrees C. After 12 h of topical administration stratum corneum was removed from fifty tapes and the ZnPc retained was evaluated by solvent extraction in dimetil-sulphoxide under ultrasonic bath. These results indicated that magnetic nanoemulsion (MNE) increase the drug release on the deeper skin layers when compared with classical formulation in the absence of magnetic particles. This could be related with the increase of biocompatibility of NDDS due to the great affinity for the polar extracelullar matrix in the skin and also for the increase in the drug partition inside of corneocites wall. (C) 2008 Elsevier B.V. All rights reserved.

Photophysical studies and in vitro skin permeation/retention of Foscan (R)/nanoemulsion (NE) applicable to photodynamic therapy skin cancer treatment.

In this work we evaluated the photophysical and in vitro properties of Foscan (R), a second-generation photosensitizer drug (PS) widely used in systemic clinical protocols for cancer therapy based on Photodynamic Therapy (PDT). We employed biodegradable nanoemulsions (NE) as a colloidal vehicle of the oil/water (o/w) type focusing in topical administration of Foscan (R) and other photosensitizer drugs. This formulation was obtained and stabilized by the methodology described by Tabosa do Egito et al.,(30) based on the mixture of two phases: an aqueous solution and an organic medium consisting of nonionic surfactants and oil. The photodynamic potential of the drug incorporated into the NE was studied by steady-state and time-resolved spectroscopic techniques. We also analyzed the in vitro biological behavior carried out in mimetic biological environment protocols based on the animal model. After topical application in a skin animal model, we evaluated the Foscan (R)/NE diffusion flux into the skin layers (stratum corneum and epidermis + dermis) by classical procedures using Franz Diffusion cells. Our results showed that the photophysical properties of PS were maintained after its incorporation into the NE when compared with homogeneous organic medium. The in vitro assays enabled the determination of an adequate profile for the interaction of this system in the different skin layers, with an ideal time lag of 6 h after topical administration in the skin model. The Foscan (R) diffusion flux (J) was increased when this PS was incorporated into the NE, if compared with its flux in physiological medium. These parameters demonstrated that the NE can be potentially applied as a drug delivery system (DDS) for Foscan (R) in both in vitro and in vivo assays, as well as in future clinical applications involving topical skin cancer PDT.

Quercetin inhibits UV irradiation-induced inflammatory cytokine production in primary human keratinocytes by suppressing NF-kappa B pathway

Background: Topical flavonoids, such as quercetin, have been shown to reduce ultraviolet (UV) irradiation-mediated skin damage. However, the mechanisms and signaling pathways involved in this protective effect are not clear. UV irradiation leads to activation of two major signaling pathways, namely nuclear factor kappa B (NF-kappa B) and activator protein-1 (AP-1) pathways. Activation of NF-kappa B pathway by UV irradiation stimulates inflammatory cytokine expression, whereas activation of AP-1 pathway by UV irradiation promotes matrix metalloproteinase (MMP) production. Both pathways contribute to UV irradiation-induced skin damage, such as photoaging and skin tumor formation. Objective: To elucidate the underlying mechanism, we examined the effect of quercetin on UV irradiation induced activation of NF-kappa B and AP-1 pathways. Methods: Primary human keratinocytes, the major skin cell type subjected to physiological solar UV irradiation, were used to study the effects of quercetin on UV irradiation-induced signal transduction pathways. Results: Quercetin decreased UV irradiation-induced NF-kappa B DNA-binding by 80%. Consequently, quercetin suppressed UV irradiation-induced expression of inflammatory cytokines IL-1 beta (similar to 60%), IL-6 (similar to 80%), IL-8 (similar to 76%) and TNF-alpha (similar to 69%). In contrast, quercetin had no effect on UV irradiation activation of three MAP kinases, ERK, JNK, or p38. Accordingly, induction of AP-1 target genes such as MMP-1 and MMP-3 by UV irradiation was not suppressed by quercetin. Conclusion: Our data indicate that the ability of quercetin to block UV irradiation-induced skin inflammation is mediated, at least in part, by its inhibitory effect on NF-kappa B activation and inflammatory cytokine production. (C) 2011 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

The influence of positive or negative charges in the passive and iontophoretic skin penetration of porphyrins used in photodynamic therapy

Meso-tetra-(N-methylpiridinium-4-yl)-porphyrin (TMPyP) and meso-tetra-(4-sulfonatophenyl)-porphyrin (TPPS(4)) are photosensitizing drugs (PS) used in photodynamic therapy (PDT). Based on the fact that these compounds present similar chemical structures but opposite charges at pH levels near physiological conditions, this work aims to evaluate the in vitro and in vivo influence of these electrical charges on the iontophoretic delivery of TMPyP and TPPS4, attempting to achieve maximum accumulation of PS in skin tissue. The iontophoretic transport of these drugs from a hydrophilic gel was investigated in vitro using porcine ear skin and vertical, flow-through diffusion cells. In vivo experiments using rats were also carried out, and the penetration of the PSs was analyzed by fluorescence microscopy to visualize the manner of how these compounds were distributed in the skin after a short period of iontophoresis application. In vitro, both passive and iontophoretic delivery of the positively charged TMPyP were much greater (20-fold and 67-fold, respectively) than those of the negatively charged TPPS(4). TPPS(4) iontophoresis in vivo increased the fluorescence of the skin only in the very superficial layers. On the other hand, iontophoresis of the positively charged drug expressively increased the rat epidermis and dermis fluorescence, indicating high amounts of this drug throughout the skin layers. Moreover, TMPyP was homogeneously distributed around and into the nuclei of the skin cells, suggesting its potential use in topical PDT. (C) 2010 Elsevier B.V. All rights reserved.

The roles played by Aspergillus nidulans apoptosis-inducing factor (AIF)-like mitochondrial oxidoreductase (AifA) and NADH-ubiquinone oxidoreductases (NdeA-B and NdiA) in farnesol resistance

Farnesol (FOH) is a nonsterol isoprenold produced by dephosphorylanon of farnesyl pyrophosphate a catabolite of the cholesterol biosynthetic pathway These isoprenoids inhibit proliferation and induce apoptosis Here we show that Aspergillus nidulans MA encoding the apoptosis-Inducing factor (AIF)-like mitochondrial oxidoreductase plays a role in the function of the mitochondrial Complex I Additionally we demonstrated that ndeA B and ndiA encode external and internal alternative NADH dehydrogenases respectively that have a function in FOH resistance When exposed to FOH the Delta aifA and Delta ndeA strains have increased ROS production while Delta ndeB Delta ndeA Delta ndeB and Andul mutant strains showed the same ROS accumulation than in the absence of FOH We observed several compensatory mechanisms affecting the differential survival of these mutants to FOH (C) 2010 Elsevier Inc All rights reserved