Application of reflectance parameters in the estimation of the structural order of coals and carbonaceous materials. Precision and bias of measurements derived from the ICCP structural working group

Optical reflectance of vitrinite is one of the fundamental physical properties that have been used for the study of coal and carbonaceous materials. Organic matter in coals and carbonaceous matter consists mainly of aromatic lamellae, whose dimensions and spatial orientation define its internal structure. Various reflectance parameters describe well the average degree of order of the molecular structure of organic matter. Moreover, reflectance parameters are numerical values which characterize the samples unambiguously, facilitating the comparison of the optical properties of different carbonaceous materials as well as comparison between optical parameters and other physical or chemical factors. The focus of this study is the evaluation of the precision and bias of reflectance measurements (R and R) performed by various analysts in different laboratories in order to check the applicability of reflectance parameters to the estimation of the structural order of coals and carbonaceous materials. Additionally, it was desirable to compare reflectance parameters with other parameters obtained by different analytical methods able to provide structural information. The consistency and repeatability of the reflectance measurements obtained by different participants turned out to enable the drawing of similar conclusions regarding the structural transformation of anthracite during heating. Good correlations were found between the reflectance parameters studied and structural factors obtained by comparative methods. The reflectance parameters examined proved to be very sensitive to any changes of the structural order of coals and carbonaceous materials and seem to be a perfect complement to structural studies made by X-ray diffraction or Raman spectroscopy

Multiscale Coarse-Graining of the Protein Energy Landscape

A variety of coarse-grained (CG) models exists for simulation of proteins. An outstanding problem is the construction of a CG model with physically accurate conformational energetics rivaling all-atom force fields. In the present work, atomistic simulations of peptide folding and aggregation equilibria are force-matched using multiscale coarse-graining to develop and test a CG interaction potential of general utility for the simulation of proteins of arbitrary sequence. The reduced representation relies on multiple interaction sites to maintain the anisotropic packing and polarity of individual sidechains. CG energy landscapes computed from replica exchange simulations of the folding of Trpzip, Trp-cage and adenylate kinase resemble those of other reduced representations; non-native structures are observed with energies similar to those of the native state. The artifactual stabilization of misfolded states implies that non-native interactions play a deciding role in deviations from ideal funnel-like cooperative folding. The role of surface tension, backbone hydrogen bonding and the smooth pairwise CG landscape is discussed. Ab initio folding aside, the improved treatment of sidechain rotamers results in stability of the native state in constant temperature simulations of Trpzip, Trp-cage, and the open to closed conformational transition of adenylate kinase, illustrating the potential value of the CG force field for simulating protein complexes and transitions between well-defined structural states

Polish consumers’ interest of game meat as a counterweight to meat from animals farmed industrially

Celem artykułu jest ocena poziomu gotowości polskich konsumentów do zwiększenia spożycia dziczyzny w najbliższych 2 latach oraz poznanie najistotniejszych dla badanych cech dziczyzny, które mogą wpłynąć na podjęcie decyzji o jej spożywaniu. Wykorzystano dane pochodzące z ogólnopolskiego badania ilościowego zrealizowanego w 2013 roku na podstawie kwestionariusza wywiadu osobistego. Badanie przeprowadzono na próbie 1000 dorosłych mieszkańców Polski. Stwierdzono, że co drugi respondent (53%), który do tej pory nie spożywał dziczyzny, wykazuje gotowość do wzrostu poziomu jej konsumpcji w najbliższych 2 latach. Większą skłonnością do zwiększenia spożywania dziczyzny charakteryzowali się mężczyźni, mieszkańcy dużych miast, osoby bardziej wykształcone w wieku od 31-40 lat. Konsumenci cenią mięso pochodzące z dzikich zwierząt ze względu na składniki odżywcze, ekologiczne pochodzenie oraz smak.The aim of the publication was to assess the level of preparedness of Polish consumers to increase consumption of venison in the next 2 years and know the most important features for the test game meat, which may affect the decision about her eating. Used data from a nationwide quantitative survey realized in 2013 on the basis of a questionnaire personal interview. The survey was sent to 1,000 adult residents of Polish. It was found that every second respondent (53%), which has so far not eat venison, shows a willingness to increase the level of its consumption in the next 2 years. Greater propensity to increase consumption of venison were characterized by men, residents of large cities, higher educated people aged 31-40 years. Consumers prefer meat from wild animals because of the nutrients, organic origin and taste

Influence of grinding on graphite crystallinity from experimental and natural data: implications for graphite thermometry and sample preparation

This paper examines the effects of shear stress on the structuralparameters that define the ‘crystallinity’ of graphite. The results show that highly crystalline graphite samples ground for up to 120 min do not undergo detectable changes in the three-dimensional arrangement of carbon layers but crystallite sizes (Lc and La) decrease consistently with increasing grinding time. Grinding also involves particle-size diminution that results in lower temperatures for the beginning of combustion and exothermic maxima in the differentialthermalanal ysis curves. These changes in the structuraland thermalcharacteristics of graphite upon grinding must be taken into account when such data are used for geothermometric estimations. Tectonic shear stress also induces reduction of the particle size and the Lc and La values of highly crystalline graphite. Thus, the temperature of formation of graphite according to structural as well as thermaldata is underestimated by up to 100ºC in samples that underwent the most intense shear stress. Therefore, application of graphite geothermometry to fluid-deposited veins where graphite is the only mineralfound should take into consideration the effect of tectonic shearing, or the estimated temperatures must be considered as minimum temperatures of formation only

Mechanical graphite transport in fault zones and the formation of graphite veins

This paper describes a vein-shaped graphite occurrence in which, for the first time, the geological, mineralogical and isotopic evidence support its formation by physical remobilization of previously formed syngenetic graphite. The deposit studied is located in the Spanish Central System and it occurs along the contact between a hydrothermal Ag-bearing quartz vein and a graphite-bearing quartzite layer. The characteristics of this occurrence differ from those of fluid-deposited vein-type graphite mineralization in that: (1) graphite flakes are oriented parallel to the vein walls; (2) graphite crystallinity is slightly lower than in the syngenetic precursor (graphite disseminated in the quartzite); and (3) the isotopic signatures of both types of graphite are identical and correspond to biogenic carbon. In addition, the P-T conditions of the hydrothermal Ag-bearing quartz veins in the study area (P <1 kbar, and T up to 360ëC) contrast with the high degree of structural order of graphite in the vein. Therefore, physical remobilization of graphite can be regarded as a suitable alternative mechanism to account for some cases of vein-shaped graphite deposits. Such a mechanism would require a previous concentration of disseminated syngenetic graphite promoted, in this case, by the retrograde solubility of quartz. This process would generate monomineralic graphite aggregates enhancing its lubricant properties and permitting graphite to move in the solid state along distances in the range of up to several metres