40 research outputs found
Optical properties of the Q1D multiband models -- the transverse equation of motion approach
The electrodynamic features of the multiband model are examined using the
transverse equation of motion approach in order to give the explanation of
several long-standing problems. It turns out that the exact summation of the
most singular terms in powers of leads to the total optical
conductivity which, in the zero-frequency limit, reduces to the results of the
Boltzmann equation, for both the metallic and semiconducting two-band regime.
The detailed calculations are carried out for the quasi-one-dimensional (Q1D)
two-band model corresponding to imperfect charge-density-wave (CDW) nesting. It
is also shown that the present treatment of the impurity scattering processes
gives the DC conductivity of the ordered CDW state in agreement with the
experimental observation. Finally, the DC and optical conductivity are
calculated numerically for a few typical Q1D cases.Comment: 14 pages, 11 figures, to appear in Fizika A (Zagreb
Electronically Induced Anomaly in LO Phonon Dispersion of High - Tc Superconductors
The strong, electronically induced anomaly in the spectrum of the
longitudinal optical (LO) phonons propagating along the main axes of the
CuO plane is tentatively attributed to the oxygen-oxygen charge transfer
between the two oxygens in the plane. It is argued that this charge transfer
can be large and that it is strongly coupled to the zone boundary LO phonons.
The corresponding negative contribution to the free energy is quartic in the LO
phonon amplitude, making the LO phonon unstable through the first order phase
transition, with a concomitant domain structure.Comment: 3 pages, 2 figure
DiversitÀt und Verteilung sulfatreduzierender Prokaryoten in marinen Sedimenten
Die dissimilatorische Sulfatreduktion ist eine der wichtigsten biologisch durchgefĂŒhrten
Stoffwechselreaktionen auf der Erde. Dies liegt unter anderem daran, dass bis zu 50%
des organischen Kohlenstoffs in marinen Sedimenten im Rahmen der an die
Sulfatreduktion gekoppelten Redoxreaktionen remineralisiert werden. 71% der
PlanetenoberflÀche sind von Meerwasser bedeckt. Im Rahmen dieser Arbeit sollte die
DiversitĂ€t der dsrAB-Gene im marinen Sediment an der KĂŒste Spitzbergens durch die
Erstellung einer dsrAB-Genbank untersucht werden. So konnten neben SRP von denen
bekannt ist, dass sie in marinen Sedimenten zu finden sind, neue Entwicklungslinien
gefunden werden, denen bislang keine kultivierten SRP zuordenbar sind. Diese neuen
Entwicklungslinien aber auch Proteobakterien dĂŒrften eine wichtige Rolle im Sediment
bei Station J spielen. Mit dem SRP-PhyloChip konnten ebenfalls Hinweise auf das
Vorhandensein von Vertretern der Desulfovibrionaceae, Desulfobacteraceae und
Desulfobulbaceae in den Sedimenten, die alle in die Klasse der Deltaproteobakterien
fallen, gesammelt werden.
Mit Real-Time-PCR wurde die Abundanz einer OTU (OTU 12), die in diese neue
Entwicklungslinie fÀllt und mit den meisten Klonen in der dsrAB-Genbank vertreten
war, gemessen. Mit einer relativen HĂ€ufigkeit von bis zu 2% ist OTU 12 in dem
untersuchten Habitat zahlenmĂ€Ăig auĂergewöhnlich dominant. AuffĂ€llig ist, dass bei der
Tiefe von sieben Zentimetern bei der die höchsten Sulfatreduktionsraten gemessen
wurden, die Abundanz von OTU 12 abnimmt, wÀhrend die Abundanz bei den Tiefen
von fĂŒnf, sechs und neun Zentimetern am höchsten ist.
ZusÀtzlich wurden alle bis zum November 2006 publizierten dsrAB-Genbanken von
marinen Sedimenten statistischen Analysen unterzogen. Vierzehn OTUs sind nur in
marinen Habitaten zu finden sind. Die Daten suggerieren, dass Desulfobacteraceae und
die neue, tiefzweigende Entwicklungslinie in allen kalten, marinen Sedimenten
vorhanden sind. Weiters wurden statistische Tests durchgefĂŒhrt, die zeigten, dass sich
die publizierten dsrAB-Genbanken in ihrer Zusammensetzung stark voneinander
unterscheiden. Aufgrund der geringen vorhanden Datenmenge bleibt unklar ob die
Unterschiede durch biogeographische oder experimentelle Faktoren verursacht wurden
Human Resource Management in the Countries of the Former Yugoslavia
Human Resource Management (HR/HRM) is closely connected to the social and economic environment in which a given organization or company operates. On this basis it may be interesting for foreign potential investors to understand both the differences and similarities in the application of HRM methods in a group of countries which had lived for a long period of time in a federation which had finally disintegrated. Such investors usually come from different environments and backgrounds and have previous experience in the application of specific forms of HRM practice. In this paper the authors try to present the development and changes in the theories and practice of Human Resource Management in most of the countries established on the territory of the former Socialist Federal Republic of Yugoslavia: Bosnia and Herzegovina, Croatia, Macedonia, Serbia and Slovenia.human resource management; economic environment; practices change; former Yugoslavia.
Mixed-phase titania foams via 3D-printing for pharmaceutical degradation
The continuing accumulation of organic micropollutants, particularly pharmaceuticals, in water is now considered an urgent threat to human health and the environment. Although the photocatalytic degradation of these compounds using slurries of photoactive nanoparticles has been proven to be highly effective at laboratory scale, this technology has not been implemented in industry due to cost and safety concerns. Here, 3D printed titania foams which are nanoparticle-free, mechanically robust and photoactive, are presented for the first time as a viable alternative to slurries for the photocatalytic degradation of pharmaceuticals. By optimizing the resin used to 3D print highly porous gyroid structures and the subsequent sintering conditions, it was possible to obtain a pure titania foam with a high anatase content, leading to the high photoactivity observed. Using carbamazepine, the pharmaceutical most found in waterways around the world, as a model pollutant, the 3D printed foams were tested in a recirculating flow reactor, with a quantum yield and electrical energy per order of 7.6 Ă 10â3 and 67.6 kW h mâ3, respectively, outperforming literature results for titania nanoparticle slurries. These results, along with the reproducibility afforded by 3D printing methods, shows a clear pathway for photocatalysts to be implemented in practice, helping to solve an urgent health problem while addressing the risk of nanoparticulate release in the environment
Vivern a virtual environment for multiscale visualization and modeling of DNA nanostructures
DNA nanostructures offer promising applications, particularly in the biomedical domain, as they can be used for targeted drug delivery, construction of nanorobots, or as a basis for molecular motors. One of the most prominent techniques for assembling these structures is DNA origami. Nowadays, desktop applications are used for the in silico design of such structures. However, as such structures are often spatially complex, their assembly and analysis are complicated. Since virtual reality (VR) was proven to be advantageous for such spatial-related tasks and there are no existing VR solutions focused on this domain, we propose Vivern, a VR application that allows domain experts to design and visually examine DNA origami nanostructures. Our approach presents different abstracted visual representations of the nanostructures, various color schemes, and an ability to place several DNA nanostructures and proteins in one environment, thus allowing for the detailed analysis of complex assemblies. We also present two novel examination tools, the Magic Scale Lens and the DNA Untwister, that allow the experts to visually embed different representations into local regions to preserve the context and support detailed investigation. To showcase the capabilities of our solution, prototypes of novel nanodevices conceptualized by our collaborating experts, such as DNA-protein hybrid structures and DNA origami superstructures, are presented. Finally, the results of two rounds of evaluations are summarized. They demonstrate the advantages of our solution, especially for scenarios where current desktop tools are very limited, while also presenting possible future research directions.Fil: Kutak, David. Masaryk University; RepĂșblica ChecaFil: Selzer, Matias Nicolas. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de Ciencias e IngenierĂa de la ComputaciĂłn; Argentina. Universidad Nacional del Sur. Departamento de Ciencias e Ingenieria de la Computacion. Laboratorio de InvestigaciĂłn y Desarrollo en VisualizaciĂłn yComputaciĂłn GrĂĄfica; ArgentinaFil: Byska, Jan. Masaryk University; RepĂșblica ChecaFil: Ganuza, MarĂa LujĂĄn. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de Ciencias e IngenierĂa de la ComputaciĂłn; Argentina. Universidad Nacional del Sur. Departamento de Ciencias e Ingenieria de la Computacion. Laboratorio de InvestigaciĂłn y Desarrollo en VisualizaciĂłn yComputaciĂłn GrĂĄfica; ArgentinaFil: Barisic, Ivan. Austrian Institute of Technology; AustriaFil: Kozlikova, Barbora. Masaryk University; RepĂșblica ChecaFil: Miao, Haichao. Austrian Institute of Technology; Austri
BPC 157 as a Therapy for Retinal Ischemia Induced by Retrobulbar Application of L-NAME in Rats
Providing NO-system importance, we suggest that one single application of the NOS-blocker L-NAME may induce retinal ischemia in rats, and that the stable pentadecapeptide BPC 157 may be the therapy, since it may interact with the NO-system and may counteract various adverse effects of L-NAME application. A rat retinal ischemia study was conducted throughout 4Â weeks, including fundoscopy, behavior presentation, tonometry, and histology assessment. Retrobulbar L-NAME application (5Â mg/kg; 0.5Â mg/0.1Â ml saline/each eye) in rats immediately produced moderate generalized irregularity in the diameter of blood vessels with moderate atrophy of the optic disc and faint presentation of the choroidal blood vessels, and these lesions rapidly progressed to the severe stage. The specific L-NAMEâinduced vascular failure points to normal intraocular pressure (except to very transitory increase upon drug retrobulbar administration). When BPC 157 (10Â ÎŒg; 10Â ng/kg, as retrobulbar application, 1Â ÎŒg; 1Â ng/0.1Â ml saline/each eye) is given at either 20Â min after L-NAME or, lately, at 48Â h after L-NAME, the regular retrobulbar L-NAME injection findings disappear. Instead, fundoscopy demonstrated only discrete generalized vessel caliber irregularity with mild atrophy of the optic disc, and then, quite rapidly, normal eye background and choroidal blood vessels, which remain in all of the subsequent periods. Also, histology assessment at 1, 2, and 4Â weeks shows that BPC 157 counteracted the damaged inner plexiform layer and inner nuclear layer, and revealed normal retinal thickness. The poor behavioral presentation was also rescued. Thus, while further studies will be done, BPC 157 counteracted L-NAMEâinduced rat retinal ischemia
Genetic determinants of response to neoadjuvant chemoradiotherapy in locally advanced rectal cancer identified by whole exome sequencing
The cornerstone in the treatment of locally advanced rectal cancer (LARC) is neoadjuvant
chemoradiotherapy (nCRT) followed by total mesorectal excision. Reliable predictors of
response to nCRT in LARC remain an unmet need in colorectal cancer research. This study
used high throughput DNA analysis to investigate genetic differences between highly
responsive tumors and tumors resistant to nCRT.European Human Genetics Conference Hybrid Conference Glasgow, Scotland, UK JUNE 10â13, 202
Literature Classification Data for a Systematic Mapping Study on Multi-Paradigm Modeling for Cyber-Physical Systems
International audienc