The influence of radio-frequency radiation on thermal stability of bovine serum albumin in aqueous solution

Protein unfolding events were studied by differential scanning calorimetry (DSC) for bovine serum albumin (BSA) aqueous solutions exposed to radio-frequency radiation. No immediate effect of this radiation on thermal unfolding of BSA was observed. The differences between irradiated and control samples have appeared during the storage of BSA solution. The irradiated samples changed faster than non-irradiated. Our results indicated that the age-related changes were stronger for 3.5 and 5 MHz than for 247 MHz frequency and dependent on energy power of radiation. Deconvolution of DSC traces allowed to study the effect of radio-frequency radiation on each component transition. This revised version was published online in July 2006 with corrections to the Cover Date.     

Insight into polymorphism of the ethosuximide (ETX)

Rich polymorphism of ethosuximide compound (ETX) is described in detail using complementary thermal analysis methods. The paper shows as well the results of differential scanning calorimetry (DSC), of polarizing microscope observations (POM) and of X-ray diffraction (XRD) measurements taken using horizontal rotating capillary method. Molecular structure of ethosuximide favors appearance of a conformationally disordered (CONDIS) crystal phase CrI in its polymorphism. Ethosuximide is a good glass former, and glass of the CrI phase was observed even for 5 °C min^?1 rate of cooling. Moreover, monotropic plastic crystal CrII phase was observed during heating above the CrI temperature range.     

Thermoanalytical studies of the ceramic-metal composites obtained by gel-centrifugal casting

Journal of Thermal Analysis and Calorimetry - Composite material with a gradient concentration of the metallic phase was prepared by the novel gel-centrifugal casting method. This method combines...     

Application of thermal analysis in the selection of polymer components used as a binder for metal injection moulding of Co–Cr–Mo alloy powder

Studies on the separation of calcium and neodymium ions by using ethylenediaminetetraacetic acid (H₄EDTA) as a complexing agent were performed. This research was undertaken due to the possibility of H₄EDTA applying to isolate rare earth elements from the solution after acidic leaching of phosphogypsum, and because of the similarity of coordination properties of calcium and lanthanides ions. The experiment was carried out in model systems containing Ca²⁺ and Nd³⁺ ions in hydrochloric or sulphuric acid. The content of calcium and neodymium metals, phase composition and thermal behaviour of the obtained products were determined by ICP-OES, FTIR, XRD and TG/DTA techniques. During the separation process, the precipitates of a light pink colour were obtained. The obtained results show that the neodymium ethylenediaminetetraacetate has been successfully formed and that the isolation of neodymium ions was more efficient in chloride medium. The precipitate included 72.2 and 3.9% of the starting amount of neodymium and calcium used in the experiment, respectively. However, in sulphates medium, these amounts were equal to 73.8 and 53.5%, respectively. Moreover, the obtained powder was polluted with sulphates. The addition of the EDTA in an excess (15%) contributed only to an increase in calcium content in the complex.

     

Multielement Analysis of South Serbian Strawberry Cultivars by Inductively Coupled Plasma—Optical Emission Spectrometry

The contents of 17 elements in thirteen strawberry cultivars grown in the five districts of Southern Serbia were determined using inductively coupled plasma optical emission spectrometry (ICP-OES). The most abundant elements are K (875–1148 mg?·?kg^?1 fresh weight), P (307–664 mg?·?kg^?1 fresh weight), Ca (192–256 mg?·?kg^?1 fresh weight), and Mg (111–189 mg?·?kg^?1 fresh weight) in all samples. Strawberries were also found to be a good source of Sr (8.05–18.6 mg?·?kg^?1 fresh weight) and Fe (3.09–10.4 mg?·?kg^?1 fresh weight). The contents of As and Cd were below the detection limit (0.0828 mg?·?kg^?1 and 0.0205 mg?·?kg^?1, respectively) in all strawberry samples, while the contents of Ni, Cr, and Cu were below the recommended tolerable levels proposed by Joint Food and Agriculture Organization of the United Nations and World Health Organization Expert Committee on Food Additives, and did not a pose a health risk for the consumer. The application of Duncan’s test showed significant differences between contents of analyzed elements in all strawberry cultivars. The highest mean levels of analyzed elements were detected in strawberries grown in the Topli?ki, Jablani?ki, and P?injski districts. The spike recovery test was used to verify the accuracy of the method, and the spike recovery was in the range 93.8–107.8%. The contents of the metals in strawberry samples were also comparable with values previously reported in the literature.     

Conjugated Polymer–Assisted Grain Boundary Passivation for Efficient Inverted Planar Perovskite Solar Cells

Grain boundaries in lead halide perovskite films lead to increased recombination losses and decreased device stability under illumination due to defect‐mediated ion migration. The effect of a conjugated polymer additive, poly(bithiophene imide) (PBTI), is investigated in the antisolvent treatment step in the perovskite film deposition by comprehensive characterization of perovskite film properties and the performance of inverted planar perovskite solar cells (PSCs). PBTI is found to be incorporated within grain boundaries, which results in an improvement in perovskite film crystallinity and reduced defects. The successful defect passivation by PBTI yields reduces recombination losses and consequently increases power conversion efficiency (PCE). In addition, it gives rise to improved photoluminescence stability and improved PSC stability under illumination which can be attributed to reduced ion migration. The optimal devices exhibit a PCE of 20.67% compared to 18.89% of control devices without PBTI, while they retain over 70% of the initial efficiency after 600 h under 1 sun illumination compared to 56% for the control devices.     

The initiation properties of 2-cyano-2-propyl hydroperoxide in oxidation processes

The initiating ability of 2-cyano-2-propyl hydroperoxide in the oxidation reaction of cumene by molecular oxygen has been investigated and compared with the initiating ability of cumene hydroperoxide.

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Die Initiierungseigenschaften von 2-Cyano-2-propyl-hydroperoxid bei Oxydations-prozessen

Zusammenfassung Es wurde die Initiierungsfähigkeit des 2-Cyan-2-hydroperoxypropans in der Oxidation von Cumol mit molekularem Sauerstoff untersucht und mit der Initiierungsfähigkeit des Cumolhydroperoxids verglichen.

     

Influence of calcination and lithium promotion on the surface properties of oxide supports

Thermal treatment and the addition of lithium influence the surface area of the oxides SiO₂, Al₂O₃ and MgO. A calcination temperature 1073 K causes a significant decrease of the surface area of SiO₂ and Al₂O₃; the same is not observed in case of MgO. Systems Li/MgO and Li/SiO₂ are characterized by a much smaller specific surface area than pure oxides thermally treated at the same temperature.     

Coordination of Schiff bases derived from pyrrole-2-carboxaldehyde and triamines to copper(II) and nickel(II) ions. Crystal structures of [Cu(C15H20N5)]NO3 and [Ni(C15H20N5)]ClO4

The Schiffbases 1,9-bis(2-pyrrolyl)-2,5,8-triazanona-1,8-diene (H₂L¹), 1,10-bis(2-pyrrolyl)-2,5,9-triazaundeca-l,9-diene (H₂L²), and 1,11-bis(2-pyrrolyl)-6-methyl-2,6,10-triazaundeca-l,10-diene (H₂L⁴) react with copper(II) nitrate or nickel(II) perchlorate in the presence of triethylamine to give new complexes [Cu(HL^1,2,4)]NO₃ and [Ni(HL^1,2,4)]ClO₄. The crystal structures of [Cu(HL²)]NO₃ and [Ni(HL²)]CIO₄ have been determined from single crystal diffractometer data and refined to finalR factors of 5.09 and 5.3%, respectively. Crystallographic data: [Cu(HL²)]NO₃: monoclinic,P2₁/c,a=10.036(2),b=14.500(2),c=13.317(2) Å,=108.14(1)°,Z=4, andd _c =11.427 Mg m^–3; [Ni(HL²)]ClO₄: monoclinic,P2₁/n,a=10.578(3),b=13.953(3),c=12.394(4) Å,=93.78(2)°,Z=4, andd _c =1.549 Mg m^–3. In both the structures the potentially pentadentate ligand (HL²)^– acts as a tetradentate one leaving one pyrrole group uncoordinated. Interesting is the metal dependent sequence of the three chelate rings. While the Ni (II) ion coordinates the (HL²)^– ligand to form a 5-5-6-membered ring system, the ring arrangement in the copper complex is of the 5-6-5 type.