Engineering and functional immobilization of opioid receptors

Opioid receptors, like many G protein-coupled receptors (GPCRs), are notoriously unstable in detergents. We have now developed a more stable variant of the mu-opioid receptor (MOR) and also a method for the immobilization of solubilized, functional opioid receptors on a solid phase (magnetic beads). Starting with the intrinsically more stable kappa-opioid receptor (KOR), we optimized the conditions (i.e. detergents and stabilizing ligands) for receptor extraction from lipid bilayers of HEK293T cells to obtain maximal amounts of functional, immobilized receptor. After immobilization, the ligand binding profile remains the same as observed for the membrane-embedded receptor. For the immobilized wild-type mu-opioid receptor, however, no conditions were found under which ligand binding capacity was retained. To solve this problem, we engineered the receptor chimera KKM where the N-terminus and the first transmembrane helix (TM1) of wild-type MOR is exchanged for the homologous receptor parts of the wild-type KOR. This hybrid receptor behaves exactly as the wild-type MOR in functional assays. Interestingly, the modified MOR is expressed at six times higher levels than wild-type MOR and is similarly stable as wild-type KOR after immobilization. Hence the immobilized MOR, represented by the chimera KKM, is now also amenable for biophysical characterization. These results are encouraging for future stability engineering of GPCR

Multicomponent Modelling Kinetics and Simultaneous Thermal Analysis of Apricot Kernel Shell Pyrolysis

Apricot kernel shells are naturally available source of biomass with potential for conversion to clean energy through a thermo-chemical process such as pyrolysis. To facilitate further process development, an advanced mathematical model which represents the process kinetics is developed and validated on the thermal decomposition studies using simultaneous thermal analysis, over a temperature range of 30-900 degrees C, at four heating rates of 5, 10, 15 and 20 degrees C min(-1), under argon atmosphere. Model-free analysis and numerically developed methods were utilized for determination of effective activation energies, pre-exponential factors and the fractional contribution. A novel approach is introduced in order to determine actual pseudo-components of studied biomass that are included in its composition. The comparative study of the obtained kinetic results was also presented. The results obtained strongly indicated that the pseudo-component reaction modelling method could be employed to predict the experimental devolatilization rate and biomass composition with a high likelihood of success

Synthesis, characterization and application of activated carbon materials obtained from the fruit of plane tree

Predmet ove teze, u širem smislu, je bila sinteza, karakterizacija i primena aktivnih ugljeničnih materijala dobijenih od ploda platana. Poznato je da postupci sinteze utiču na mikrostrukturu i svojstva materijala. Ugljenični materijali mogu biti napravljeni sa širokim spektrom struktura, kompozicija i svojstava, u zavisnosti od prirode organskih prekursora i procesnih parametra. Bilo koji materijal koji sadrži ugljenik može se koristiti za proizvodnju ugljeničnih materijala. Zbog toga, biomasa kao prirodna mešavina ugljovodonika, dostupna u velikom obimu odličan je preduslov. Isto tako, to je ekološki obnovljivi resurs. Postoje značajne ekonomske i tehničke prednosti u korišćenju biomase. Za prevođenje biomase (ploda platana) u ugljenični materijal korišćena je hidrotermalna sinteza na niskim temperaturama kao i piroliza na višim temperaturama. Ugljenični materijal je izložen metodama aktiviranja kao što su fizička (CO2) i hemijska (H3PO4) aktivacija u pokušaju da se dobije aktivni ugljenični materijal sa visokim stepenom adsorpcije za određenu primenu. Adsorpcija na aktivnom uglju ima primenu u prehrambenoj, farmaceutskoj, hemijskoj, automobilskoj, nuklearnoj industriji, itd. Primeri za to su razni filteri, adsorbenti, nosači katalizatora, baterije, kao elektrodni materijal u elektrohemiji i raznim drugim različitim granama industrije. 6 Ugljenični materijali se uveliko intenzivno proučavaju kao elektrodni materijali za elektrohemijske kondenzatore usled njihove visoke specifične površine, dobre električne provodljivosti i niske cene. Istraživači, različitim mnogobrojnim istraživanjima pokušavaju da sintetišu različite forme ugljeničnih materijala sa razvijenom specifičnom površinom i razvijenom poroznošću u cilju što boljeg skladištenja nаеleketrisanja. Karakterizacijom datih materijala u pogledu vrednosti specifične površine, veličine i raspodele pora, prisustva i raspodele površinskih grupa, stepena uređenosti i čistoće, pokušava da se ustanovi koji su ključni parametari za najefikasnije skladištenje energije ugljeničnog kondenzatora. Sintetisani su mikroporozni i mezoporozni ugljenični materijali dobijeni od ploda platana sa različitim, visokim specifičnim površinama na različitim temperaturama...In general terms, the subject of this thesis, was the synthesis, characterization and application of active carbon materials obtained from the plane tree fruit. It is known that synthetic methods influence the microstructure and properties of the material. Carbon materials can be obtained with a wide range of structures, compositions and properties, depending on the nature of organic precursors and process parameters. Any carbon-containing material can be used for the production of carbon materials. Therefore, biomass as a natural mixture of hydrocarbons, available on a large scale, is a great prerequisite. Likewise, it is an ecological renewable resource. There are significant economic and technical advantages in the use of biomass. Hydrothermal synthesis at low temperatures, as well as pyrolysis at higher temperatures, was used to convert biomass (plane tree fruit) into carbon material. Carbon material is exposed to activation methods such as physical (CO2) and chemical (H3PO4) activation in an attempt to obtain an active carbon material with a high degree of adsorption for a particular application. Adsorption on activated carbon has application in food, pharmaceutical, chemical, automotive, nuclear industry, etc. Examples are various filters, adsorbents, catalyst carriers, batteries, electrode materials in electrochemistry and various other industries. 9 Carbon materials are extensively studied as electrode materials for electrochemical condensers due to their high specific surface area, good electrical conductivity and low price. Researchers, by various numerous studies, are trying to synthesize different forms of carbon materials with a developed specific surface and developed porosity in order to improve storage of electrical charge. By specifying the given materials in terms of the value of the specific surface area, size and distribution of pores, the presence and distribution of surface groups, the degree of orderliness and purity, an attempt is made to determine the key parameters for the most efficient energy storage of the carbon capacitor. Microporous and mesoporous carbon materials derived from the plane tree fruit with different, high specific surfaces, were synthesized at different temperatures..

Anatomy of coronary sinus ostium

Background: The coronary sinus is the main cardiac vein and it has become a clinically important structure especially through its role in providing access for different cardiac procedures. Materials and methods: The study was carried out on 100 randomly selected adult human cadaver hearts fixed in 10% formalin. The transverse and craniocaudal diameters of the coronary sinus ostium (CSO) were directly measured. The presence of the Thebesian valve was noted and the anatomical details of the valve were documented in each case in terms of the shape and extent of coverage of the CSO. Results: Considerable variations in the diameter of the CSO were observed. The mean craniocaudal diameter of the CSO was 8.1 ± 1.51 mm, and the mean transverse diameter was 7.67 ± 1.72 mm. Heart specimens without Thebesian valve tended to have larger ostia. The mean craniocaudal diameter and the mean transverse diameter of the CSO were statistically larger in the specimens without Thebesian valves (p = 0.000 and p = 0.001, respectively). Conclusions: The Thebesian valves were observed in 86 hearts, and a wide variety of their morphology was seen. The majority of the Thebesian valves were semilunar in shape (74.42%). The extent to which the valve covered the ostium was variable, including remnant valves that covered < 15% of the CSO (35%), and valves that were large and covered at least 75% of the CSO (22.09%). In 3 specimens the valve completely occluded the ostium.

Properties of Self-compacting Concrete Produced with Biomass Wood Ash

The demand of the contemporary society for renewable energy sources lead to the increase of the bio-power plants. Accordingly, the amount of ash generated by burning the biomass is increased, and its disposal becomes a large environmental problem. The paper presents the research of potential use of biomass wood ash as a partial replacement for coal fly ash (10%, 20%, 30% and 40% of mass) in production of self-compacting concrete (SCC). The effects of biomass wood ash on the properties of SCC in fresh and hardened states have been examined, as well as on the properties of durability. Test results indicated that the biomass wood ash slightly reduces the flowability and passing ability of SCC, while its addition enhances the viscosity of SCC and significantly prevents segregation and bleeding. SCCs with the contents of biomass wood ash up to 20% have approximately same mechanical strength as the reference mixture. Biomass wood ash has no negative effect on the resistance of concrete to the action of water under pressure, but a decrease of freeze/thaw resistance with de-icing salt is detected as its contents increases. The addition of biomass wood ash into SCC increases the drying shrinkage in the initial period of drying (up to 14 days), and it is decreased in a later phase

Structural properties of carbon microspheres obtained by hydrothermal treatment of fructose

A carbon-rich solid product has been synthesized by hydrothermal treatment from fructose with HNO3 at temperature of 140°C. The concentration of the precursor was changed in order to investigate how its change influences formation of carbon microspheres. pH value for every sample was the same, i.e. 1. The formation of the carbon rich solid through the hydrothermal carbonization of fructose is the consequence of dehydration reactions. Obtained carbon material is made of spherical micrometer-sized particles with the diameter in the 1-6 µm range, which can be modulated by modifying the concentration of fructose in solution. The best results are obtained with smaller concentrations of fructose. Spherical particles have more regular shape and they are less agglomerated. The structure and surface chemical properties of obtained material were characterized by scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectra and elemental analysis

Theoretical and experimental study of polycrystalline phases obtained by the nanometric ZnTiO3 powder sintering

In this study we have combined two research methods: structure prediction of ZnTiO3 using computational SPuDS software, and the characterization of binary oxides obtained from ZnO TiO2 system. Pure nanosized ZnTiO3 (99.5%), was compacted in cylindrical shape specimens by uniaxial double sided compaction and then sintered in air atmosphere in a dilatometric device [1,2]. One compact was sintered up to 915 °C to retain metastabile ZnTiO3 and held 5 minutes on that temperature, and another one at the same conditions, but now up to 970 °C to induce phase transition and to obtain stabile Zn2TiO4 and TiO2 according to phase diagram [2]. Reheated samples obtained at different characteristic temperatures in air were analyzed by X-ray diffraction (XRD). The infrared attenuated total reflectivity measurements confirmed XRD results. In order to estimate theoretical stability of these perovskite structure, Goldschmidt tolerance factor Gt and global instability index GII were calculated. Furthermore, the Ti valence states were determined by bond valence calculations (BVC). Also, we have investigated the formation of new phases (Zn2Ti3O8, TiO2 and Zn2TiO4) originating from ZnTiO3 with temperature change, as well as the relation between the crystal structures which have been predicted and the structure of the phases we have experimentally observed

Uklanjanje olova i kadmijuma iz vodenog rastvora koristeći okrakalcijum-fosfat kao adsorbent

Octacalcium phosphate (OCP) is a material from the calcium phos-phate group with a crystal structure similar to hydroxyapatite. The removal process of lead and cadmium in aqueous solution using octacalcium phosphate material was investigated. OCP material was synthesized by the solution pre-cipitation method. The structural and phase properties of OCP before and after the removal process were determined by the X-ray diffraction (XRD) method. Microstructural and semi-quantitative analysis of the material was investigated by scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDS). Characteristic bands and functional group determination were revealed using the Fourier-transform infrared spectroscopy with attenuated total reflection (FTIR-ATR). As target pollutants, Cd(II) and Pb(II) were chosen in adsorption experiments. Results show that OCP in the first 10 min has a very fast removal rate for Pb(II); the equilibrium state was reached after 10 min with more than 98 % adsorption efficiency. Results for Cd(II), results showed the same removal rate but somewhat lower adsorption efficiency, amounted to approximately 63 %

Basilar artery fenestration

The posterior circulation of the brain constitutes the vertebrobasilar system and its branches, which are responsible for about 30% of the brain’s blood supply. The aim of this study was to describe the anomalies of the basilar artery, especially fenestrations. For that purpose, we examined 50 patients with computed tomography (CT) angiography during an 8-month period. In the CT reports of 2 (4%) patients of the 50 analysed, fenestration was found at the proximal basilar trunk. The two fenestrations in our series were not associated with aneurysms. No collateral branches originated from the two limbs of the fenestration. In conclusion, basilar artery fenestrations are a rare finding. The data derived from this study are useful teaching material for anatomists, and for the radiologists and neurosurgeons they are important for diagnostic and intervention procedures such as CT, magnetic resonance imaging, angiography, and surgical and endovascular procedures. (Folia Morphol 2011; 70, 2: 80–83

Morphologic characteristics of sacra associated with assimilation of the last lumbar vertebra

Background: The impact of lumbosacral transitional states on biomechanics of load transmission between the spine and the legs has been sporadically reported. The aims of the study were to identify morphostructural alterations of sacra associated with assimilation of the last lumbar vertebra and to analyse them in the light of their biomechanical impact. Materials and methods: Linear dimensions of sacrum, its body and base and articular surfaces were measured in 31 normal and 41 transitory sacra. Nineteen sacra presented articular and 22 osseous fusion of the last lumbar vertebra. Measured parameters were compared between normal sacra and the two variations of transitory sacra. Results: Sacra with articular fusion of the last lumbar vertebra showed more pronounced concavity of the sacral curvature and wider than long sacral bodies. The first sacral segment was modified, broaden, ventrally wider and elevated. Almost the whole segment bore at its sides auricular surfaces. Very small portion of the segment was non-articular with less pronounced wedging. Sacra with osseous fusion of the last lumbar vertebra showed similar concavity of the sacral curvature as normal sacra, but longer than wide sacral bodies. The ventral sloping half of the newly formed first segment bore auricular surfaces. The non-articular part was enlarged with pronounced wedging. Conclusions: The term “sacralisation“ includes both types of transitory sacra with mutually different morphostructural characteristics in contrast to the normal sacra. Analysis of these morphologic variations may help in understanding the different biomechanical properties and patterns of load transmissio