Ultrafast Momentum Imaging of Pseudospin-Flip Excitations in Graphene

The pseudospin of Dirac electrons in graphene manifests itself in a peculiar momentum anisotropy for photo-excited electron-hole pairs. These interband excitations are in fact forbidden along the direction of the light polarization, and are maximum perpendicular to it. Here, we use time- and angle-resolved photoemission spectroscopy to investigate the resulting unconventional hot carrier dynamics, sampling carrier distributions as a function of energy and in-plane momentum. We first show that the rapidly-established quasi-thermal electron distribution initially exhibits an azimuth-dependent temperature, consistent with relaxation through collinear electron-electron scattering. Azimuthal thermalization is found to occur only at longer time delays, at a rate that depends on the substrate and the static doping level. Further, we observe pronounced differences in the electron and hole dynamics in n-doped samples. By simulating the Coulomb- and phonon-mediated carrier dynamics we are able to disentangle the influence of excitation fluence, screening, and doping, and develop a microscopic picture of the carrier dynamics in photo-excited graphene. Our results clarify new aspects of hot carrier dynamics that are unique to Dirac materials, with relevance for photo-control experiments and optoelectronic device applications.Comment: 23 pages, 12 figure

Ergonomics in Dental Practice

Dentalna se ergonomija definira kao prilagodba na uvjete i metode rada liječnika - tima uz poštovanje vlastitih fizičkih i psihičkih kapaciteta kako bi zdravo i konforno funkcionirali u svome profesionalnom angažmanu. Praktičarima se često događa paradoks: dok skrbe o oralnome zdravlju svojih pacijenata, potpuno zanemaruju skrb o vlastitom. U radu su prikazane osnovne upute stomatologu- timu kako da se služe vlastitim kapacitetima, mogućnostima opreme, instrumentarija i organizacije posla da bi poštivali ergonomske norme i smanjili rizik od profesionalnih bolesti.Dental ergonomics is based on planning the adapting tasks and equipment of the dentists to promote comfort and efficiency and production in the work environment. In practice we are often faced with the paradox: while we take care of the oral health of our patients, we completely neglect care about our health condition. In this article we will present basic guidelines for the dentist/team on how to use personal capacities, capacities of dental equipment, instruments an menagement of dental team work in order to achieve ergonomic standards and to minimize risk of occupational disease

Clinical Characteristics of TMJD in a Kuwaiti Population

Poremećaji temporomandibularnih zglobova manifestiraju se znacima i simptomima koji ne zahvaćaju samo čeljusne zglobove nego i žvačnu muskulaturu i okolna tkiva. Najčešći znaci i simptomi jesu: bol u zglobovima i mišićima, poremećaji mandibularnih kretnji, zvučne senzacije, hipertrofija žvačnih mišića, glavobolja i vrtoglavica. Ranija su istraživanja pokazala da 70% stanovniπtva ima bar jedan znak ili simptom poremećaja temporomandibularnih zglobova. No to je klinički potvrđeno kod samo 38% slučajeva (Mc Neill 1993, Nouralach H et al 1998). U naše istraživanje uključili smo 144 pacijenta s poremećajima u području temporomandibularnih zglobova (102 žene i 42 muškarca). Pacijenti su bili podijeljeni u dvije skupine: lokalno stanovništvo (60,4%) i stranci (39,6%). Od ukupnoga broja pacijenata šezdeset četiri postotka žalilo se na smetnje pri otvaranju usta. No klinički je potvrđeno da takve smetnje ima samo 37,5% naših slučajeva. Zvučne senzacije bile su čest nalaz, koji je klinički potvrđen kao škljocanje u 88% slučajeva i kao krepoitacije u 11,2% pacijenata. Razmjerno mali broj pacijenata imao je bruksizam (12,5%), a artritis 11,1%. Mi smo također utvrdili da je glavobolja u oboljelih ispitanika bila čest klinički simptom (50,2%). Glavni znaci i simptomi poremećaja temporomandibularnih zglobova utvrđeni su u objema skupinama ispitanika. Žene su se češće žalile na bol u zglobu, zvučne senzacije i glavobolju nego muškarci. Lokalno stanovništvo je češće bolovalo od poremećaja temporomandibularnih zglobova nego stranci.Different signs and symptoms both in TMJ itself and masticator muscles and surrounding tissues clinically manifest temporomandibular joint disorders (TMJD). The most common signs and symptoms are muscles and joint pain, mandibular movement disturbance, sound sensations, masticator muscle hypertrophy, headache and dizziness. Previous investigations revealed that 70% of the population complain of having at least one of these signs and symptoms, of which 38% have been clinically proved (Mc Neill 1993, Nouralach H et al 1998). Patients and Methods: TMJD was investigated in 144 patients (female = 102, male = 42). Patients were devided into two groups: local inhabitants (60.4%) and expatriates (39.6%). Sixty-four and half percent (64.5%) of our patients complained of having mouth opening disturbance, which was clinically confirmed in only 37.5% of cases. Sound sensation was a very common sign, clinically confirned as a click in 88% and as crepitation in 11.2%. A relatively small number of patients had bruxism (12.5%), and arthritis (11.1%). We also found headache as a common clinical symptom (50.2%). The main common signs and symptoms of TMJD were positive in both local and expatriate inhabitants. Females suffered more frequently than males, complaining of pain, sound sensation and headache. Local inhabitants had more frequent TMJD

Novel symmetric bis-benzimidazoles: Synthesis, DNA/RNA binding and antitrypanosomal activity.

The novel benzimidazol-2-yl-fur-5-yl-(1,2,3)-triazolyl dimeric series with aliphatic and aromatic central linkers was successfully prepared with the aim of assessing binding affinity to DNA/RNA and antitrypanosomal activity. UV-Visible spectroscopy, thermal denaturation showed interaction of heterocyclic bis-amidines with ctDNA. Circular dichroism studies indicated uniform orientation of heterocyclic bis-amidines along the chiral double helix axis, revealing minor groove binding as the dominant binding mode. The amidino fragment and 1,4-bis(oxymethylene)phenyl spacer were the main determinants of activity against Trypanosoma brucei. The bis-benzimidazole imidazoline 15c, which had antitrypanosomal potency in the submicromolar range and DNA interacting properties, emerged as a candidate for further structural optimization to obtain more effective agents to combat trypanosome infections

Activation of Innate and Adaptive Immunity by a Recombinant Human Cytomegalovirus Strain Expressing an NKG2D Ligand.

Development of an effective vaccine against human cytomegalovirus (HCMV) is a need of utmost medical importance. Generally, it is believed that a live attenuated vaccine would best provide protective immunity against this tenacious pathogen. Here, we propose a strategy for an HCMV vaccine that aims at the simultaneous activation of innate and adaptive immune responses. An HCMV strain expressing the host ligand ULBP2 for the NKG2D receptor was found to be susceptible to control by natural killer (NK) cells, and preserved the ability to stimulate HCMV-specific T cells. Infection with the ULBP2-expressing HCMV strain caused diminished cell surface levels of MHC class I molecules. While expression of the NKG2D ligand increased the cytolytic activity of NK cells, NKG2D engagement in CD8+ T cells provided co-stimulation and compensated for lower MHC class I expression. Altogether, our data indicate that triggering of both arms of the immune system is a promising approach applicable to the generation of a live attenuated HCMV vaccine

Characteristics and drivers of forest cover change in the post-socialist era in Croatia: evidence from a mixed-methods approach

© 2016, Springer-Verlag Berlin Heidelberg.Extensive forests in Croatia represent an important biological and economic resource in Europe. They are characterised by heterogeneity in forest management practices dating back to the socialist planned economy of the pre-1991 era. In this study we investigated the difference in rates of deforestation and reforestation in private- and state-owned forests during the post-socialist period and the causal drivers of change. The selected region of Northern Croatia is characterised by a high percentage of privately owned forests with minimal national monitoring and control. We used a mixed-methods approach which combines remote sensing, statistical modelling and a household-based questionnaire survey to assess the rates of forest cover change and factors influencing those changes. The results show that predominantly privately owned forests in Northern Croatia have recorded a net forest loss of 1.8 % during the 1991–2011 period, while Croatia overall is characterised by a 10 % forest cover increase in predominantly state-owned forests. Main factors influencing forest cover changes in private forests are slope, altitude, education structure, population age and population density. The results also show that the deforestation in private forests is weakening overall, mostly due to the continuation of the de-agrarisation and de-ruralisation processes which began during socialism

Multi-dimensional modeling and simulation of semiconductor nanophotonic devices

Self-consistent modeling and multi-dimensional simulation of semiconductor nanophotonic devices is an important tool in the development of future integrated light sources and quantum devices. Simulations can guide important technological decisions by revealing performance bottlenecks in new device concepts, contribute to their understanding and help to theoretically explore their optimization potential. The efficient implementation of multi-dimensional numerical simulations for computer-aided design tasks requires sophisticated numerical methods and modeling techniques. We review recent advances in device-scale modeling of quantum dot based single-photon sources and laser diodes by self-consistently coupling the optical Maxwell equations with semiclassical carrier transport models using semi-classical and fully quantum mechanical descriptions of the optically active region, respectively. For the simulation of realistic devices with complex, multi-dimensional geometries, we have developed a novel hp-adaptive finite element approach for the optical Maxwell equations, using mixed meshes adapted to the multi-scale properties of the photonic structures. For electrically driven devices, we introduced novel discretization and parameter-embedding techniques to solve the drift-diffusion system for strongly degenerate semiconductors at cryogenic temperature. Our methodical advances are demonstrated on various applications, including vertical-cavity surface-emitting lasers, grating couplers and single-photon sources

Sustainable rural development in Serbia - relationship between population dynamicss and environment

In this paper the relationship between populatiOn and the environment, and their influence on rural sustainability in Serbia, using quantitative typology of rural areas will be examined. The typology is based on the net relative change of population in rural areas in Serbia, according to the difference between the number of inhabitants at the end of the studied period (2011) and a hypothetical population that each rural settlement would have if the population in base year (1961) was changed proportionally to the change of total rural population. Research results indicate types of population dynamics of rural areas with different scale and intensity of environmental degradation: progressive type with favorable human and economic potentials, strong urban influence and huge environmental transformation; stagnant type with advanced agricultural and demographic dimension which imposed pressures to the natural environment; regressive type with heterogeneous demographic, social and economic features, and different impacts on natural and social environment, and dominant regressive type of rural areas highly characterised by the deficient in human and economic potential and preserved natural resources. Based on analysed rural particularities it can be concluded that the different human, environmental and economic potentials and obstacles of determined types of rural areas should be the starting point in defining appropriate sustainable strategies and development directions

Ergonomics in Dental Practice

Dentalna se ergonomija definira kao prilagodba na uvjete i metode rada liječnika - tima uz poštovanje vlastitih fizičkih i psihičkih kapaciteta kako bi zdravo i konforno funkcionirali u svome profesionalnom angažmanu. Praktičarima se često događa paradoks: dok skrbe o oralnome zdravlju svojih pacijenata, potpuno zanemaruju skrb o vlastitom. U radu su prikazane osnovne upute stomatologu- timu kako da se služe vlastitim kapacitetima, mogućnostima opreme, instrumentarija i organizacije posla da bi poštivali ergonomske norme i smanjili rizik od profesionalnih bolesti.Dental ergonomics is based on planning the adapting tasks and equipment of the dentists to promote comfort and efficiency and production in the work environment. In practice we are often faced with the paradox: while we take care of the oral health of our patients, we completely neglect care about our health condition. In this article we will present basic guidelines for the dentist/team on how to use personal capacities, capacities of dental equipment, instruments an menagement of dental team work in order to achieve ergonomic standards and to minimize risk of occupational disease