Stoicorum veterum fragmenta

Reprint of the 1903-1924 ed., published by B. G. Teubner, Leipzig

The effects of vehicle and region of application on in vitro penetration of testosterone through canine skin

The effects of the vehicles phosphate-buffered saline (PBS), ethanol (EtOH; 50% in PBS w/w) and propylene glycol (PG; 50% in PBS w/w) and the region of administration on in vitro transdermal penetration of testosterone was investigated in the dog. Skin was harvested from the thorax, neck (dorsal part) and groin regions of greyhounds after euthanasia and stored at -20 degrees C until required. The skin was then de-frosted and placed into Franz-type diffusion cells which were maintained at approximately 32 degrees C by a water-bath. Saturated solutions of testosterone, containing trace amounts of radiolabelled (C-14) testosterone, in each vehicle were applied to the outer (stratum corneum) surface of each skin sample and aliquots of receptor fluid were collected at 0, 2, 4, 8, 16, 20, 22 and 24 h and analysed for testosterone by scintillation counting. The maximum flux (J(max)) of testosterone was significantly higher for all sites when dissolved in a vehicle containing 50% EtOH or 50% PG, compared to PBS. In contrast, higher residues of testosterone were found remaining within the skin when PBS was used as a vehicle. This study shows that variability in percutaneous penetration of testosterone could be expected with formulation design and site of application. (C) 2004 Elsevier Ltd. All rights reserved.

Designing stuffed hetero-fullerene nano-clusters: C26B46N12 and C14B58N12Li12

The stuffed fullerene-like nano clusters based on the approximately spherical B-84, (B-12@B-12@B-60, fragment of the beta-rhombohedral boron), are proposed using Wade's Rules and the criterion of overlap matching. Thus the fifty additional electrons required to make the B-84 skeleton electron sufficient, are provided by replacing 26 boron atoms by carbon atoms and 12 boron atoms by nitrogen atoms giving rise to C26B46N12. This particular combination has the added advantage of the fullerene surface made from C2B3N five-membered rings having less strain arising from the pyramidalization of the sp(2) hybridised trigonal planar carbon or nitrogen; the natural angle needed to have an optimum overlap is not far from the 31.7 degrees required for icosahedral symmetry. The advantage from overlap-matching can be further increased by capping the two pentagonal faces of the cluster by a Li atom each, keeping the electron count the same by replacing 12 carbon atoms with 12 boron atoms. DFT based computational results support these formulations.

Dinâmica populacional de minicírculos de cinetoplastos em Leishmania infantum chagasi

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Unconventional correlated systems

This work comprises three different types of unconventional correlated systems.rnChapters 3-5 of this work are about the open shell compounds Rb4O6 and Cs4O6. These mixed valent compounds contain oxygen in two different modifications: the closed-shell peroxide anion is nonmagnetic, whereas the hyperoxide anion contains an unpaired electrons in an antibonding pi*-orbital. Due to this electron magnetic ordering is rendered possible. In contrast to theoretical predictions, which suggested half-metallic ferromagnetism for Rb4O6,rndominating antiferromagnetic interactions were found in the experiment. Besidesrna symmetry reduction due to the mixed valency, strong electronic correlations of this highly molecular system determine its properties; it is a magnetically frustrated insulator. The corresponding Cs4O6 was found to show similar properties.rnChapters 6-9 of this work are about intermetallic Heusler superconductors. rnAll of these superconductors were rationally designed using the van Hove scenario as a working recipe. A saddle point in the energy dispersion curve of a solid leads to a van Hove singularity in the density of states. In the Ni-based and Pd-based Heusler superconductors presented in this work this sort of a valence instability occurs at the high-symmetry L point and coincides or nearly coincides with the Fermi level. The compounds escape the high density of states at the Fermi energy through a transition into the correlated superconducting state.rnChapter 10 of this work is about the tetragonally distorted ferrimagnetic DO22 phase of Mn3Ga. This hard-magnetic modification is technologically useful for spin torque transfer applications. The phase exhibits two different crystallographic sites that are occupied by Mn atoms and can thus be written as Mn2MnGa. The competition between the mainly itinerant moments of the Mn atoms at the Wyckoff position 4d and the localized moments of the Mn atoms at the Wyckoff position 2b leads to magnetic correlations. The antiferromagnetic orientation of these moments determines the compound to exhibit a resulting magnetic moment of approximately 1 µB per formula unit in a partially compensated ferrimagnetic configuration.

In silico identification and characterisation of 17 polymorphic anonymous non-coding sequence markers (ANMs) for red grouse (Lagopus lagopus scotica)

Peer reviewed

Potential soil carbon sequestration in overgrazed grassland ecosystems

Excessive grazing pressure is detrimental to plant productivity and may lead to declines in soil organic matter. Soil organic matter is an important source of plant nutrients and can enhance soil aggregation, limit soil erosion, and can also increase cation exchange and water holding capacities, and is, therefore, a key regulator of grassland ecosystem processes. Changes in grassland management which reverse the process of declining productivity can potentially lead to increased soil C. Thus, rehabilitation of areas degraded by overgrazing can potentially sequester atmospheric C. We compiled data from the literature to evaluate the influence of grazing intensity on soil C. Based on data contained within these studies, we ascertained a positive linear relationship between potential C sequestration and mean annual precipitation which we extrapolated to estimate global C sequestration potential with rehabilitation of overgrazed grassland. The GLASOD and IGBP DISCover data sets were integrated to generate a map of overgrazed grassland area for each of four severity classes on each continent. Our regression model predicted losses of soil C with decreased grazing intensity in drier areas (precipitation less than 333 mm yr(-1)), but substantial sequestration in wetter areas. Most (93%) C sequestration potential occurred in areas with MAP less than 1800 mm. Universal rehabilitation of overgrazed grasslands can sequester approximately 45 Tg C yr(-1), most of which can be achieved simply by cessation of overgrazing and implementation of moderate grazing intensity. Institutional level investments by governments may be required to sequester additional C.

The optimal temperature of first aid treatment for partial thickness burn injuries

Using our porcine model of deep dermal partial thickness burn injury, various cooling techniques (15 degrees C running water, 2 degrees C running water, ice) of first aid were applied for 20 minutes compared with a control (ambient temperature). The subdermal temperatures were monitored during the treatment and wounds observed and photographed weekly for 6 weeks, observing reepithelialization, wound surface area and cosmetic appearance. Tissue histology and scar tensile strength were examined 6 weeks after burn. The 2 degrees C and ice treatments decreased the subdermal temperature the fastest and lowest, however, generally the 15 and 2 degrees C treated wounds had better outcomes in terms of reepithelialization, scar histology, and scar appearance. These findings provide evidence to support the current first aid guidelines of cold tap water (approximately 15 degrees C) for 20 minutes as being beneficial in helping to heal the burn wound. Colder water at 2 degrees C is also beneficial. Ice should not be used.

Experimental investigation of an unstable ring resonator with 90-deg beam rotation for a chemical oxygen iodine laser

We report the experimental results of an unstable ring resonator with 90-deg beam rotation for a kilowatt class chemical oxygen iodine laser (COIL). The distributions of near-field phase and far-field intensity were measured. A beam quality of 1.6 was achieved when the COIL average output power was approximately 5 kW. (C) 1999 Optical Society of America.

Palaeobiology of an extinct Ice Age mammal: Stable isotope and cementum analysis of giant deer teeth

The extinct giant deer, Megaloceros giganteus, is among the largest and most famous of the cervids. Megaloceros remains have been uncovered across Europe and western Asia. but the highest concentrations come from Irish bogs and caves Although Megaloceros has enjoyed a great deal of attention over the centuries, paleobiological study has focused oil morphometric and distributional work until now. This paper presents quantitative data that have implications for understanding its sudden extirpation in western Europe during a period of global climate change approximately 10.600 C-14 years ago (ca 12,500 calendar years BP). We report here the first stable isotope analysis of giant deer teeth. which we combine with dental cementum accretion in order to document age, diet and life-history seasonality from birth until death Enamel delta C-13 and delta O-18 measured in the second and third molars from seven individual giant deer Suggest a grass and forbbased diet supplemented with browse in a deteriorating. possibly water-stressed, environment, and a season of birth around spring/early summer Cementurm data indicate that the ages of the specimens ranged from 6.5 to 14 years and that they possessed mature antlers by autumn, similar to extant cervids. In addition. the possibility for combining these two techniques in future mammalian paleoccological studies is considered. The data presented in this study imply that Megoloceros would have indeed been vulnerable to extirpation during the terminal Pleistocene in Ireland. and this information is relevant to understanding the broader pattern of its extinction.

A novel three-dimensional culture system for isolation and clonal propagation of neural stem cells using a thermo-reversible gelation polymer

In the present study, we examined the possible utility of a three-dimensional culture system using a thermo-reversible gelation polymer to isolate and expand neural stem cells (NSCs). The polymer is a synthetic biologically inert polymer and gelates at temperatures higher than the gel-sol transition point ( approximately 20 degrees C). When fetal mouse brain cells were inoculated into the gel, spherical colonies were formed ( approximately 1% in primary culture and approximately 9% in passage cultures). The spheroid-forming cells were positive for expression of the NSC markers nestin and Musashi. Under conditions facilitating spontaneous neural differentiation, the spheroid-forming cells expressed genes characteristic to astrocytes, oligodendrocytes, and neurons. The cells could be successively propagated at least to 80 poly-D-lysines over a period of 20 weeks in the gel culture with a growth rate higher than that observed in suspension culture. The spheroids formed by fetal mouse brain cells in the gel were shown to be of clonal origin. These results indicate that the spheroid culture system is a convenient and powerful tool for isolation and clonal expansion of NSCs in vitro.

Otimização da torre de arrefecimento da Artlant PTA

Trabalho Final de Mestrado para obtenção de grau de Mestre em Engenharia Química e Biológica

Thermoluminescence, electron paramagnetic resonance and optical absorption in natural and synthetic rhodonite crystals

Thermoluminescence, electron paramagnetic resonance and optical absorption properties of rhodonite, a natural silicate mineral, have been investigated and compared to those of synthetic crystal, pure and doped. The TL peaks grow linearly for radiation dose up to 4 kGy, and then saturate. In all the synthetic samples, 140 and 340 degrees C TL peaks are observed; the difference occurs in their relative intensities, but only 340 degrees C peak grows strongly for high doses. Al(2)O(3) and Al(2)O(3) + CaO-doped synthetic samples presented several decades intenser TL compared to that of synthetic samples doped with other impurities. A heating rate of 4 degrees C/s has been used in all the TL readings. The EPR spectrum of natural rhodonite mineral has only one huge signal around g = 2.0 with width extending from 1,000 to 6,000 G. This is due to Mn dipolar interaction, a fact proved by numerical calculation based on Van Vleck dipolar broadening expression. The optical absorption spectrum is rich in absorption bands in near-UV, visible and near-IR intervals. Several bands in the region from 540 to 340 nm are interpreted as being due to Mn(3+) in distorted octahedral environment. A broad and intense band around 1,040 nm is due to Fe(2+). It decays under heating up to 900 degrees C. At this temperature it is reduced by 80% of its original intensity. The pink, natural rhodonite, heated in air starts becoming black at approximately 600 degrees C.

Compatibility and decomposition kinetics studies of prednicarbate alone and associated with glyceryl stearate

In this work, TG/DTG and DSC techniques were used to the determination of thermal behavior of prednicarbate alone and associated with glyceryl stearate excipient ( 1: 1 physical mixture). TG/DTG curves obtained for the binary mixture showed a reduction of approximately 37 degrees C to the thermal stability of drug (T(dm/dt-0) (Max)(DTG)). The disappearance of stretching band at 1280 cm(-1) (nu(as) C-O, carbonate group) and the presence of streching band with less intensity at 1750 cm(-1) (nu(s) C-O, ester group) in IR spectrum obtained to the binary mixture submitted at 220 degrees C, when compared with IR spectrum of drug submitted to the same temperature, confirmed the chemical interaction between these substances due to heating. Kinetics parameters of decomposition reaction of prednicarbate were obtained using isothermal (Arrhenius equation) and non-isothermal (Ozawa) methods. The reduction of approximately 45% of activation energy value (E(a)) to the first step of thermal decomposition reaction of drug in the 1:1 (mass/mass) physical mixture was observed by both kinetics methods.

Síntese e caracterização de óxidos de cério e cobalto obtidos por gel-combustão e Pechini aplicados às reações de oxidação de n-hexano

Oxide type spinel AB2O4 presents structure adjusted for application in the automobile industry. The spinel of cobalt has many practical applications had its excellent physical and chemical properties such as catalyst in hydrocarbon oxidation reaction. The CeO2 has been used in many of these processes because it assigns to a material with excellent thermal resistance and mechanics, high capacity of oxygen stockage (OSC) among others properties. This work deals with the synthesis, characterization and catalytic application of spinel of cobalt and CeO2 with fluorita structure, obtained for method of Pechini and method of Gel-Combustion. The process of Pechini, the puff was obtained at 300 ºC for 2 h in air. In the process of Gel-Combustion the approximately at 350 ºC material was prepared and burnt for Pyrolysis, both had been calcined at 500 ºC, 700 ºC, 900 ºC and 1050 ºC for 2 h in air. The materials of the calcinations had been characterized by TG/DTA, electronic microscopy of sweepings (MEV), spectroscopy of absorption in the infra-red ray (FTIR) and diffraction of X-rays (DRX). The obtained material reaches the phase oxide at 450 oC for Pechini method and 500 °C for combustion method. The samples were submitted catalytic reaction of n-hexane on superficies of materials. The reactor function in molar ration of 0, 85 mol.h-1.g-1 and temperature of system was 450 °C. The sample obtained for Pechini and support in alumine of superficial area of 178,63 m2.g-1 calcined at 700 ºC, give results of catalytic conversions of 39 % and the sample obtained for method of gel-combustion and support in alumina of 150 mesh calcined at 500 ºC result 13 % of conversion. Both method were selective specie C1