3D bioprinting in biotechnology

I am sure all of us have heard about 3D printers. They can print plastic models with different shapes and structures. And today I am going to show you, how we can use them in medicine and biotechnology

Hydrodynamic model for electron-hole plasma in graphene

We propose a hydrodynamic model describing steady-state and dynamic electron and hole transport properties of graphene structures which accounts for the features of the electron and hole spectra. It is intended for electron-hole plasma in graphene characterized by high rate of intercarrier scattering compared to external scattering (on phonons and impurities), i.e., for intrinsic or optically pumped (bipolar plasma), and gated graphene (virtually monopolar plasma). We demonstrate that the effect of strong interaction of electrons and holes on their transport can be treated as a viscous friction between the electron and hole components. We apply the developed model for the calculations of the graphene dc conductivity, in particular, the effect of mutual drag of electrons and holes is described. The spectra and damping of collective excitations in graphene in the bipolar and monopolar limits are found. It is shown that at high gate voltages and, hence, at high electron and low hole densities (or vice-versa), the excitations are associated with the self-consistent electric field and the hydrodynamic pressure (plasma waves). In intrinsic and optically pumped graphene, the waves constitute quasineutral perturbations of the electron and hole densities (electron-hole sound waves) with the velocity being dependent only on the fundamental graphene constants.Comment: 11 pages, 6 figure

The Capacitive Magnetic Field Sensor

The results of a study of sensitive element magnetic field sensor are represented in this paper. The sensor is based on the change of the capacitance with an active dielectric (ferrofluid) due to the magnitude of magnetic field. To prepare the ferrofluid magnetic particles are used, which have a followingdispersion equal to 50 < [the empty set] <= 56, 45 < [the empty set] <= 50, 40 < [the empty set] <=45 and [the empty set] <= 40 micron of nanocrystalline alloy of brand 5BDSR. The dependence of the sensitivity of the capacitive element from the ferrofluid with different dispersion of magnetic particles is considered. The threshold of sensitivity and sensitivity of a measuring cell with ferrofluid by a magnetic field was determined. The experimental graphs of capacitance change of the magnitude of magnetic field are presented

The spectrum of hot methane in astronomical objects using a comprehensive computed line list

Hot methane spectra are important in environments ranging from flames to the atmospheres of cool stars and exoplanets. A new spectroscopic line list, 10to10, for $^{12}$CH$_4$ containing almost 10 billion transitions is presented. This comprehensive line list covers a broad spectroscopic range and is applicable for temperatures up to 1 500 K. Previous methane data are incomplete leading to underestimated opacities at short wavelengths and elevated temperatures. Use of 10to10 in models of the bright T4.5 brown dwarf 2MASS 0559-14 leads to significantly better agreement with observations and in studies of the hot Jupiter exoplanet HD 189733b leads to up to a twentifold increase in methane abundance. It is demonstrated that proper inclusion of the huge increase in hot transitions which are important at elevated temperatures is crucial for accurate characterizations of atmospheres of brown dwarfs and exoplanets, especially when observed in the near-infrared.Comment: PNAS, Early Edition, June 16, 201

Possible zoonotic viral threats associated with bats in southern Ukraine

The paper is devoted to evaluation of some bat species inhabiting Ukraine as potential reservoir hosts of highly dangerous viruses including lyssaviruses, MERS-CoV-related coronaviruses, and arboviruses. Repeated catches of bats by a domestic cat were described. Laboratory examination of the caught bats did not detect infection with coronaviruses or arboviruses such as West Nile, tick-borne encephalitis, Crimean-Congo hemorrhagic fever, Tribec and Uukuniyemi viruses. The analysis of the literature showed the possibility of persistence of dangerous viruses among examined bat species. The fact that domestic cats may prey on bats that are potential reservoir hosts of dangerous viruses should be considered as a risk factor for infection of humans and cats with lyssaviruses causing rabies, and infection of humans with coronaviruses that may be associated with severe respiratory diseases.Повідомлення присвячено оцінці ролі деяких видів кажанів, що населяють південь України, як потенційних резервуарів особливо небезпечних вірусів — ліссавірусів, коронавірусів, споріднених з вірусом близькосхідного респіраторного синдрому, та арбовірусів. Описано повторні випадки вилову кажанів свійським котом. Лабораторне обстеження відловлених котом кажанів не виявило наявності у них коронавірусів і таких арбовірусів, як віруси Західного Нілу, кліщового енцефаліту, Кримської-Конго геморагічної гарячки, Трибеч та Уукуніємі. Проведений аналіз даних з літератури свідчить про можливость персистенції небезпечних вірусів серед обстеженних видів кажанів. Той факт, що домашні коти можуть полювати на кажанів як потенційних резервуарів (носіїв) небезпечних вірусів, слід розглядати як фактор ризику для зараження людей та котів ліссавірусами, які викликають сказ, а людей — коронавірусами, що можуть спричиняти важкі респіраторні захворювання

Blind extraction of an exoplanetary spectrum through Independent Component Analysis

Blind-source separation techniques are used to extract the transmission spectrum of the hot-Jupiter HD189733b recorded by the Hubble/NICMOS instrument. Such a 'blind' analysis of the data is based on the concept of independent component analysis. The de-trending of Hubble/NICMOS data using the sole assumption that nongaussian systematic noise is statistically independent from the desired light-curve signals is presented. By not assuming any prior, nor auxiliary information but the data themselves, it is shown that spectroscopic errors only about 10 - 30% larger than parametric methods can be obtained for 11 spectral bins with bin sizes of ~0.09 microns. This represents a reasonable trade-off between a higher degree of objectivity for the non-parametric methods and smaller standard errors for the parametric de-trending. Results are discussed in the light of previous analyses published in the literature. The fact that three very different analysis techniques yield comparable spectra is a strong indication of the stability of these results.Comment: ApJ accepte

Graphene makes our life easier

Graphene is one of the most perspective modern materials. Graphene is an atomic-scale honeycomb lattice made of carbon atoms and discovered only a few decades ago

Graphene makes our life easier

Graphene is one of the most perspective modern materials. Graphene is an atomic-scale honeycomb lattice made of carbon atoms and discovered only a few decades ago