Romanian Academy

About: Romanian Academy is a archive organization based out in Bucharest, Romania. It is known for research contribution in the topics: Population & Nonlinear system. The organization has 3662 authors who have published 10491 publications receiving 146447 citations. The organization is also known as: Academia Română & Societatea Literară Română.

Protein specific N-glycosylation of tyrosinase and tyrosinase-related protein-1 in B16 mouse melanoma cells.

Abstract: Tyrosinase and tyrosinase-related protein-1 (TRP-1) are two melanogenic enzymes that regulate melanin biosynthesis. Both are glycoproteins and belong to the TRP-1 gene family. They share a significant level of sequence similarity in several regions, including the catalytic domain and the potential N-glycosylation sites. We have recently shown that inhibition of the early steps of N-glycan processing in B16F1 cells dramatically affects tyrosinase activity and melanin synthesis. We present here results on N-glycan processing of TRP-1 and tyrosinase and compare the maturation process and activity of both glycoproteins in the presence of inhibitors of the endoplasmic reticulum stages of N-glycosylation. N-glycan analysis reveals that each of these two glycoproteins contains a mixture of high-mannose and sialylated complex N-glycans. However, in contrast to TRP-1, tyrosinase presents a homogeneous high-mannose glycoform, also. In the presence of alpha-glucosidases inhibitors, the maturation of tyrosinase N-glycans is completely inhibited, whereas TRP-1 is still able to acquire some complex glycans, indicating that endomannosidase acts preferentially on the later glycoprotein. In addition, the dopa-oxidase activity of tyrosinase is totally abolished, whereas for TRP-1 it is only partially affected. The results suggest that despite their structural similarity, tyrosinase is more sensitive than TRP-1 to perturbations of early N-glycan processing, in terms of maturation and catalytical activity.

Near infra-red spectroscopy of the asteroid 21 Lutetia - II. Rotationally resolved spectroscopy of the surface

Abstract: Aims In the framework of the ground-based science campaign dedicated to the encounter with the Rosetta spacecraft, the mineralogy of the asteroid (21) Lutetia was investigated Methods Near-infrared (NIR) spectra of the asteroid in the 08−25 μm spectral range were obtained with SpeX/IRTF in remote observing mode from Meudon, France in March and April 2006 We analysed these data together with previously acquired spectra - March 2003, August 2004 I-band relative photometric data obtained on 20 January 2006 using the 105 cm telescope from Pic du Midi, France has been used to build the ephemeris for physical observations A χ2 test using meteorite spectra from the RELAB database was performed in order to find the best fit of complete visible + infrared (VNIR) spectra of Lutetia Results The new spectra reveal no absorption features We find a clear spectral variation (slope), and a good correspondence between spectral variations and rotational phase Two of the most different spectra correspond to two opposite sides of the asteroid (sub-Earth longitude difference around 180◦) For the neutral spectra a carbonaceous chondrite spectrum yields the best fit, while for those with a slightly positive slope the enstatitic chondrite spectra are the best analog Based on the chosen subset of the meteorite samples, our analysis suggests a primitive, chondritic nature for (21) Lutetia Differences in spectra are interpreted in terms of the coexistence of several lithologies on the surface where the aqueous alteration played an important role

Axisymmetric Swirling Flow Simulation of the Draft Tube Vortex in Francis Turbines at Partial Discharge

Abstract: The flow in the draft tube cone of Francis turbines operated at partial discharge is a complex hydrodynamic phenomenon where an incoming steady axisymmetric swirling flow evolves into a three-dimensional unsteady flow field with precessing helical vortex (also called vortex rope) and associated pressure fluctuations. The paper addresses the following fundamental question: is it possible to compute the circumferentially averaged flow field induced by the precessing vortex rope by using an axisymmetric turbulent swirling flow model? In other words, instead of averaging the measured or computed 3D velocity and pressure fields we would like to solve directly the circumferentially averaged governing equations. As a result, one could use a 2D axi-symmetric model instead of the full 3D flow simulation, with huge savings in both computing time and resources. In order to answer this question we first compute the axisymmetric turbulent swirling flow using available solvers by introducing a stagnant region model (SRM), essentially enforcing a unidirectional circumferentially averaged meridian flow as suggested by the experimental data. Numerical results obtained with both models are compared against measured axial and circumferential velocity profiles, as well as for the vortex rope location. Although the circumferentially averaged flow field cannot capture the unsteadiness of the 3D flow, it can be reliably used for further stability analysis, as well as for assessing and optimizing various techniques to stabilize the swirling flow. In particular, the methodology presented and validated in this paper is particularly useful in optimizing the blade design in order to reduce the stagnant region extent, thus mitigating the vortex rope and expending the operating range for Francis turbines.

Environmental and socioeconomic assessment of impacts by mining activities—a case study in the Certej River catchment, Western Carpathians, Romania

Abstract: Background, aim and scope In the region of the Apuseni Mountains, part of the Western Carpathians in Romania, metal mining activities have a long-standing tradition. These mining industries created a clearly beneficial economic development in the region. But their activities also caused impairments to the environment, such as acid mine drainage (AMD) resulting in long-lasting heavy metal pollution of waters and sediments. The study, established in the context of the ESTROM programme, investigated the impact of metal mining activities both from environmental and socioeconomic perspectives and tried to incorporate the results of the two approaches into an integrated proposition for mitigation of mining-related issues.

An LRR/Malectin Receptor-Like Kinase Mediates Resistance to Non-adapted and Adapted Powdery Mildew Fungi in Barley and Wheat.

Abstract: Pattern recognition receptors (PRRs) belonging to the multigene family of receptor-like kinases (RLKs) are the sensing devices of plants for microbe- or pathogen-associated molecular patterns released from microbial organisms. Here we describe Rnr8 (for required for nonhost resistance 8) encoding HvLEMK1, a LRR-malectin domain-containing transmembrane RLK that mediates nonhost resistance of barley to the non-adapted wheat powdery mildew fungus Blumeria graminis f.sp. tritici. Transgenic barley lines with silenced HvLEMK1 allow entry and colony growth of the non-adapted pathogen, although sporulation was reduced and final colony size did not reach that of the adapted barley powdery mildew fungus Blumeria graminis f.sp. hordei. Transient expression of the barley or wheat LEMK1 genes enhanced resistance in wheat to the adapted wheat powdery mildew fungus while expression of the same genes did not protect barley from attack by the barley powdery mildew fungus. The results suggest that HvLEMK1 is a factor mediating nonhost resistance in barley and quantitative host resistance in wheat to the wheat powdery mildew fungus.