Raman spectra of monolayer, few-layer, and bulk ReSe₂:An anisotropic layered semiconductor

Rhenium diselenide (ReSe₂) is a layered indirect gap semiconductor for which micromechanical cleavage can produce monolayers consisting of a plane of rhenium atoms with selenium atoms above and below. ReSe₂ is unusual among the transition-metal dichalcogenides in having a low symmetry; it is triclinic, with four formula units per unit cell, and has the bulk space group <i>P</i>1̅. Experimental studies of Raman scattering in monolayer, few-layer, and bulk ReSe₂ show a rich spectrum consisting of up to 16 of the 18 expected lines with good signal strength, pronounced in-plane anisotropy of the intensities, and no evidence of degradation of the sample during typical measurements. No changes in the frequencies of the Raman bands with layer thickness down to one monolayer are observed, but significant changes in relative intensity of the bands allow the determination of crystal orientation and of monolayer regions. Supporting theory includes calculations of the electronic band structure and Brillouin zone center phonon modes of bulk and monolayer ReSe₂ as well as the Raman tensors determining the scattering intensity of each mode. It is found that, as for other transition-metal dichalcogenides, Raman scattering provides a powerful diagnostic tool for studying layer thickness and also layer orientation in few-layer ReSe₂

More actors, different play: sphenoethmoid cell intimately related to the maxillary nerve canal and cavernous sinus apex

Abstract The sphenoid sinus is one of the most morphologically variable and surgically important structures of the skull base. Located below the sella turcica, neighbored by parasellar regions, such as the orbital apex, pterygopalatine fossa and lateral sellar region (cavernous sinus), it is clinically related to these and surgically relevant as corridor for various approaches. Moreover, at the sphenoethmoidal junction, important variations occur, most of these related to the presence of the Onodi cells and the intrasinusal protrusions of the optic nerve. That is why any identified and previously undescribed morphological variation at that level must be added to the well-established protocols, clinical and surgical. During a retrospective CT study of the sphenoid sinus anatomical features a previously unreported morphology was encountered and is reported here. It refers to a unilateral sphenoethmoid cell (SEC), Onodi-positive, not only overriding the superior aspect of the sphenoid but also its lateral side to get intimately related to the maxillary nerve. As that SEC expanded medially to the cavernous sinus apex, it altered the usual endosinusal morphological correlations and also added itself within the limits of the Mullan&apos;s triangle. It appears so that such postero-infero-lateral extended pneumatization of an Onodi cell alters the surgical landmarks and also can blur clinical pictures, by adding maxillary and pterygopalatine signs and symptoms

A Modular Bioplatform Based on a Versatile Supramolecular Multienzyme Complex Directly Attached to Graphene

© 2016 American Chemical Society. Developing generic strategies for building adaptable or multifunctional bioplatforms is challenging, in particular because protein immobilization onto surfaces often causes loss of protein function and because multifunctionality usually necessitates specific combinations of heterogeneous elements. Here, we introduce a generic, modular bioplatform construction strategy that uses cage-like supramolecular multienzyme complexes as highly adaptable building blocks immobilized directly and noncovalently on graphene. Thermoplasma acidophilum dihydrolipoyl acyltransferase (E2) supramolecular complexes organize as a monolayer or can be controllably transferred onto graphene, preserving their supramolecular form with specific molecular recognition capability and capacity for engineering multifunctionality. This E2-graphene platform can bind enzymes (here, E1, E2's physiological partner) without loss of enzyme function; in this test case, E1 catalytic activity was detected on E2-graphene over 6 orders of magnitude in substrate concentration. The E2-graphene platform can be multiplexed via patterned cotransfer of differently modified E2 complexes. As the E2 complexes are robust and highly customizable, E2-graphene is a platform onto which multiple functionalities can be built

Self-consistent charge and dipole density functional tight binding method and application to carbon-based systems

The density functional tight binding (DFTB) method is a fast, semi-empirical, total energy electronic structure method based upon and parameterized to density functional theory (DFT). The standard self-consistent charge (SCC) DFTB approximates the charge fluctuations in a system using a multipole expansion truncated to the monopole term. For systems with asymmetric charge distributions, such as might be induced by an applied external field, higher terms in the multipole expansion are likely to be important. We have extended the formalism to include dipoles (SCCD), have implemented the method computationally, and test it by calculating the response of various carbon nanotubes and fullerenes to an applied electric field. A comparison of polarizabilities with experimental data or more sophisticated DFT calculations indicates a substantial improvement over standard SCC-DFTB. We also discuss the issues surrounding parameterization of the new SCCD-DFTB scheme

RECENT TRENDS AND PROSPECTIVE EVALUATIONS ON THE PORK MARKET IN ROMANIA

The scientific paper had the purpose to identify and highlight specific trends of pork market both in Romania and in selected EU member states (Hungary, Bulgaria, Greece, Slovakia, Poland, Lithuania, Latvia). In the Romanian agri-food system, there is a correlation between pork production and purchasing power. Romania's pork consumption is still substantially below that of the European average of 46.4kg per capita. A positive aspect is the lifting of the ban on Romanian pork to the European Union. Therefore, it could be considered a boost of the food industry, as the trade system could be developed, satisfying local and overseas supply and demand. Taking into account the current tendencies for pork production and exchanges in European Union, one could find out that there is a reduction of livestock in the European Union. Pork production depends on country and it is linked to feed prices and reorganization. The analysis is based on statistical data regarding pork production, highlighting its evolution of pork production before and after our country’s accession to the European Union, comparing pork production evolution at national level to the average one of other countries, during the period of time 2001-2012. There were also determined the adjusted values of the chronological series as well as the extrapolated ones for 2013and 201