Interaction of giant extracellular Glossoscolex paulistus hemoglobin (HbGp) with ionic surfactants: A MALDI-TOF-MS study

The giant extracellular hemoglobin of Glossoscolex paulistus (HbGp) is constituted by approximately 144 subunits containing heme groups with molecular masses in the range of 16-19 kDa forming a monomer (d) and a trimer (abc), and around 36 non-heme structures, named linkers (L). Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF-MS) analysis was performed recently, to obtain directly information on the molecular masses of the different subunits from HbGp in the oxy-form. This technique demonstrated structural similarity between HbGp and the widely studied hemoglobin of Lumbricus terrestris (HbLt). Indeed, two major isoforms (d(1) and d(2)) of identical proportions with masses of 16,355+/-25 and 16,428+/-24 Da, respectively, and two minor isoforms (d(3) and d(4)) with masses around 16.6 kDa were detected for monomer d of HbGp. In the present work, the effects of anionic sodium dodecyl sulfate (SDS) and cationic cethyltrimethyl ammonium chloride (CTAC) on the oligomeric structure of HbGp have been studied by MALDI-TOF-MS in order to evaluate the interaction between ionic surfactants and HbGp. The data obtained with this technique show an effective interaction of cationic surfactant CTAC with the two isoforms of monomer d, d(1) and d(2), both in the whole protein as well as in the pure isolated monomer. The results show that up to 10 molecules of CTAC are bound to each isoform of the monomer. Differently, the mass spectra obtained for SDS-HbGp system showed that the addition of the anionic surfactant SDS does not originate any mass increment of the monomeric subunits, indicating that SDS-HbGp interaction is, probably, significantly less effective as compared to CTAC-HbGp one. The acid pI of the protein around 5.5 is, probably, responsible for this behavior. The results of this work suggest also some interaction of both surfactants with linker chains as well as with trimers, as judged from observed mass increments. Our data are consistent with a recent spectroscopic study showing a strong interaction between CTAC and HbGp at physiological pH [P.S.Santiago, et al, Biochim. Biophys. Acta. 1770 (2007) 506-517.]. (C) 2007 Elsevier B.V. All rights reserved.

Luminous efficiency enhancement of PVK based OLEDs with fac-[ClRe(CO)(3)(bpy)]

The luminous efficiency of organic light-emitting diodes based on poly(N-vinylcarbazole), PVK, was improved by adding fac-[ClRe(CO)(3)(bpy)], bpy = 2,2`-bipyridine, to PVK host. Emissive layers with various Re(I) complex/host ratio were employed and optoelectronic properties were compared with the single PVK device. The single PVK device exhibits a characteristic electroluminescence with blue emission, lambda(max) 420 nm, assigned to the PVK excimer. On the other hand, the intense and broad band at lambda(max) 580 nm of the Re(I) complex/PVK OLEDs is ascribed to the metal-to-ligand charge transfer excited state emission of fac-[ClRe(CO)(3)(bpy)]. At 30 V, the device luminous efficiency increased from 16 mcd/A for the single PVK device to 211 mcd/A for the 11% (w/w) Re(I) complex/PVK OLED, in which fac-[ClRe(CO)(3)(bpy)] acts as an electron-trap in PVK films. The device current is space-charge limited and exhibits typical emissive layer thickness dependence. (C) 2011 Elsevier B.V. All rights reserved.

Interface tailoring for adhesion enhancement of diamond-like carbon thin films

We have explored the suitability and characteristics of interface tailoring as a tool for enhancing the adhesion of hydrogen-free diamond-like carbon (DLC) thin films to silicon substrates. DLC films were deposited on silicon with and without application of an initial high energy carbon ion bombardment phase that formed a broad Si-C interface of gradually changing Si:C composition. The interface depth profile was calculated using the TRIDYN simulation program, revealing a gradient of carbon concentration including a region with the stoichiometry of silicon carbide. DLC films on silicon, with and without interface tailoring, were characterized using Raman spectroscopy, scanning electron microscopy, atomic force microscopy and scratch tests. The Raman spectroscopy results indicated sp3-type carbon bonding content of up to 80%. Formation of a broadened Si:C interface as formed here significantly enhances the adhesion of DLC films to the underlying silicon substrate. (C) 2012 Elsevier B.V. All rights reserved.

Dissolution Enhancement and Characterization of Nimodipine Solid Dispersions with Poloxamer 407 or PEG 6000

The solid dispersion approach is an alternative to increase drug solubility. Many carriers have been studied, but there is few information about poloxamer 407 (P407). Consequently, the objective of this study was to evaluate P407 as a carrier for nimodipine solid dispersions and to compare its solubility and dissolution rates with those from polyethylene glycol (PEG 6000). The solid dispersions were prepared by the hot melting and solvent methods and they were characterized by FTIR, DSC, solubility, and dissolution tests. The results indicated a three-fold increase in solid dispersions solubility in the presence with P407 than those prepared with PEG.

Enhancement of Nematic Order and Global Phase Diagram of a Lattice Model for Coupled Nematic Systems

We use an infinite-range Maier-Saupe model, with two sets of local quadrupolar variables and restricted orientations, to investigate the global phase diagram of a coupled system of two nematic subsystems. The free energy and the equations of state are exactly calculated by standard techniques of statistical mechanics. The nematic-isotropic transition temperature of system A increases with both the interaction energy among mesogens of system B, and the two-subsystem coupling J. This enhancement of the nematic phase is manifested in a global phase diagram in terms of the interaction parameters and the temperature T. We make some comments on the connections of these results with experimental findings for a system of diluted ferroelectric nanoparticles embedded in a nematic liquid-crystalline environment.

Optical Excitations and Field Enhancement in Short Graphene Nanoribbons

The optical excitations of elongated graphene nanoflakes of finite length are investigated theoretically through quantum chemistry semiempirical approaches. The spectra and the resulting dipole fields are analyzed, accounting in full atomistic details for quantum confinement effects, which are crucial in the nanoscale regime. We find that the optical spectra of these nanostructures are dominated at low energy by excitations with strong intensity, comprised of characteristic coherent combinations of a few single-particle transitions with comparable weight. They give rise to stationary collective oscillations of the photoexcited carrier density extending throughout the flake and to a strong dipole and field enhancement. This behavior is robust with respect to width and length variations, thus ensuring tunability in a large frequency range. The implications for nanoantennas and other nanoplasmonic applications are discussed for realistic geometries.

SOAP processing performance and enhancement

The web services (WS) technology provides a comprehensive solution for representing, discovering, and invoking services in a wide variety of environments, including Service Oriented Architectures (SOA) and grid computing systems. At the core of WS technology lie a number of XML-based standards, such as the Simple Object Access Protocol (SOAP), that have successfully ensured WS extensibility, transparency, and interoperability. Nonetheless, there is an increasing demand to enhance WS performance, which is severely impaired by XML's verbosity. SOAP communications produce considerable network traffic, making them unfit for distributed, loosely coupled, and heterogeneous computing environments such as the open Internet. Also, they introduce higher latency and processing delays than other technologies, like Java RMI and CORBA. WS research has recently focused on SOAP performance enhancement. Many approaches build on the observation that SOAP message exchange usually involves highly similar messages (those created by the same implementation usually have the same structure, and those sent from a server to multiple clients tend to show similarities in structure and content). Similarity evaluation and differential encoding have thus emerged as SOAP performance enhancement techniques. The main idea is to identify the common parts of SOAP messages, to be processed only once, avoiding a large amount of overhead. Other approaches investigate nontraditional processor architectures, including micro-and macrolevel parallel processing solutions, so as to further increase the processing rates of SOAP/XML software toolkits. This survey paper provides a concise, yet comprehensive review of the research efforts aimed at SOAP performance enhancement. A unified view of the problem is provided, covering almost every phase of SOAP processing, ranging over message parsing, serialization, deserialization, compression, multicasting, security evaluation, and data/instruction-level processing.

Reproductive apparatus of the male giant hermit crab Petrochirus diogenes (Anomura, Diogenidae): morphology and phylogenetic implications

We describe the male reproductive apparatus of the giant hermit crab Petrochirus diogenes, with morphological and biometric analyses of the spermatophore, the gonopore and the ultrastructure of the spermatozoa. Specimens were collected from the southern coast of Sao Paulo, Brazil. Morphological analyses were done using stereoscopic, light, transmission and scanning electron microscopy. The reproductive system of this hermit crab is composed of elongate and lobular testes followed by vasa deferentia that connect to the exterior via gonopores. The gonopores are ovoid and surrounded by setae, and each gonopore is composed of a membranous operculum that forms a depression constituting the gonopore opening. The gonopore constitutes a unique structure among the Diogenidae due to its number of setae. The spermatophores are tripartite, composed of a sperm-containing ampulla, a peduncle and a proximal foot. The spermatozoon has 3 main regions (acrosomal vesicle, nucleus and cytoplasm). The structure of the spermatophore indicates that this species can be considered an exception within Diogenidae with regard to spermatophore morphology and can therefore be used for phylogenetic inferences.

Strangeness Enhancement in Cu-Cu and Au-Au Collisions at root s(NN)=200 GeV

We report new STAR measurements of midrapidity yields for the Lambda, (Lambda) over bar, K-S(0), Xi(-), (Xi) over bar (+), Omega(-), (Omega) over bar (+) particles in Cu + Cu collisions at root s(NN) = 200 GeV, and midrapidity yields for the Lambda, (Lambda) over bar, K-S(0) particles in Au + Au at root s(NN) = 200 GeV. We show that, at a given number of participating nucleons, the production of strange hadrons is higher in Cu + Cu collisions than in Au + Au collisions at the same center-of-mass energy. We find that aspects of the enhancement factors for all particles can be described by a parametrization based on the fraction of participants that undergo multiple collisions.

Early development, survival and growth rates of the giant clam Tridacna crocea (Bivalvia: Tridacnidae)

Tridacnid clams are conspicuous inhabitants of Indo-Pacific coral reefs and are traded and cultivated for the aquarium and food industries. In the present study, daily growth rates of larvae of the giant clam Tridacna crocea were determined in the laboratory during the first week of life. Adults were induced to spawn via intra-gonadal serotonin injection through the byssal orifice. After spawning oocytes were collected, fertilized and kept in 3 L glass beakers and raceways treated with antibiotics to avoid culture contamination. Larvae were fed twice with the microalga Isochrysis galbana and zooxanthellae were also offered twice during the veliger stage (days 4 and 6). Larval length was measured using a digitizing tablet coupled to a microcomputer. Larval mortality was exponential during the first 48 hours of life declining significantly afterwards. Mean growth rate was 11.3 mu m day-1, increasing after addition of symbionts to 18.0 mu m day-1. Survival increased to ca. 75% after the addition of zooxanthellae. The results describe the growth curve for T. crocea larvae and suggest that the acquisition of symbionts by larvae may be useful for larval growth and survival even before larvae have attained metamorphosis.

Treatment of central giant cell lesions using bisphosphonates with intralesional corticosteroid injections

Central giant cell lesions are benign intraosseous proliferative lesions that have considerable local aggressiveness. Nonsurgical treatment methods, such as intralesional corticosteroid injections, systemic calcitonin and interferon have been reported. Recently, bisphosphonates have been used to treat central giant cell lesions. A case of a 36-year-old male with a central giant cell lesion crossing the mandibular midline was treated with intralesional corticosteroids combined with alendronate sodium for the control of systemic bone resorption. The steroid injections and the use of bisphosphonates were stopped after seven months when further needle penetration into the lesion was not possible due to new bone formation. After two years, the bony architecture was near normal, and only minimal radiolucency was present around the root apices of the involved teeth. The patient was followed up for four years, and panoramic radiography showed areas of new bone formation. Thus far, neither recurrence nor side effects of the medication have been detected.

Tamoxifen Subcellular Localization; Observation of Cell-Specific Cytotoxicity Enhancement by Inhibition of Mitochondrial ETC Complexes I and III

Recently, a nongenomic cytotoxic component of the chemotherapeutic agent tamoxifen (TAM) has been identified that predominantly triggers mitochondrial events. The present study delineates the intracellular fate of TAM and studies its interaction with a spectrum of cell homeostasis modulators primarily relevant to mitochondria. The subcellular localization of TAM was assessed by confocal fluorescence microscopy. The effect of the modulators on TAM cytotoxicity was assessed by standard MTT assays. Our findings show that in estrogen receptor positive MCF7 breast adenocarcinoma cells and DU145 human prostate cancer cells, TAM largely accumulates in the mitochondria and endoplasmic reticulum, but not lysosomes. Our results further demonstrate that in MCF7, but not in DU145 cells, mitochondrial electron transport chain complex I and III inhibitors exacerbate TAM toxicity with an order of potency of myxothiazol = stigmatellin > rotenone > antimycin A, suggesting a cell-specific cytotoxic interplay between mitochondrial complex I and III function and TAM action.

Enhancement of the Nonlinear Optical Absorption of the E7 Liquid Crystal at the Nematic-Isotropic Transition

We present an experimental study of the nonlinear optical absorption of the eutectic mixture E7 at the nematic-isotropic phase transition by the Z-scan technique, under continuous-wave excitation at 532 nm. In the nematic region, the effective nonlinear optical coefficient beta, which vanishes in the isotropic phase, is negative for the extraordinary beam and positive for an ordinary beam. The parameter , whose definition in terms of the nonlinear absorption coefficient follows the definition of the optical-order parameter in terms of the linear dichroic ratio, behaves like an order parameter with critical exponent 0.22 +/- 0.05, in good agreement with the tricritical hypothesis for the nematic-isotropic transition.

Initial experience with Pomerantzeff's technique for reduction of the size of giant left atrium

Introduction: The most common indication for surgical correction of giant left atrium is associated with mitral valve insufficiency with or without atrial fibrillation. Several techniques for this purpose are already described with varying results. Objective: To present the initial experience with the tangential triangular resection technique (Pomerantzeff). Methods: From 2002 to 2010, four patients underwent mitral valve operation with reduction of left atrial volume by the technique of triangular resection tangential in our service. Three patients were female. The age ranged from 21 to 51 years old. The four patients presented with atrial fibrillation. Ejection fraction of left ventricle preoperatively ranged from 38% to 62%. The left atrial diameter ranged from 78mm to 140mm. After treatment of mitral dysfunction, the left atrium was reduced by resecting triangular tangential posterior wall between the pulmonary veins to avoid anatomic distortion of the mitral valve or pulmonary veins, reducing tension in the suture line. Results: Average hospital stay was 21.5 +/- 6.5 days. The mean cardiopulmonary bypass time was 130 +/- 30 minutes. There was no surgical bleeding or mortality in the postoperative period. All patients had sinus rhythm restored in the output of cardiopulmonary bypass, maintaining this rate postoperatively. The average diameter of the left atrium was reduced by 50.5% +/- 19.5%. The left ventricular ejection fraction improved in all patients. Conclusion: Initial results with this technique have shown effective reduction of the left atrium.