18 results on '"Cǎtǎlin Lazăr"'
Search Results
2. New method for the isotopic study of ancient conchiolin from archaeological shells of freshwater mussels (Unionoida)
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Ana García-Vázquez, Valentin Radu, and Cǎtǎlin Lazăr
- Abstract
Freshwater mussels shells are common remains in archaeological sites of the Gumelnița culture (5th millennium BC, Romania), and were part of the diet of its ancient inhabitants. The proteins of these shells are often preserved and can be used for paleodietary and paleoecosystem reconstructions by stable isotopes. To obtain the empirical relationship between the isotopic composition of sell organic matrix and soft tissues, we analysed the body (foot and mantle), the muscle, the conchiolin of the shell and stomach contents of modern individuals of Unio tumidus from the Danube. In addition, modern shells were digested in 5M HCl and archaeological in 1M HCl to obtain the shell organic matrix or conchiolin. We established a quality criterion for freshwater mussel shell conchiolin of 3.6 (± 0.3) for the C:N and obtained an offset of Δ15Nconchiolin-defatted body= +0.95‰, Δ13Cconchiolin-defatted body = +0.93‰ for the soft tissues, and an offset of Δ15Nconchiolin-muscle= +1.7‰, Δ13Cconchiolin-muscle= +0.3‰ for the muscle. Freshwater mussels from Gumelnița showed that they came from different sources (rivers, lakes, ponds…) but which not necessarily have to come from long distances since all these different habitats were present in the vicinity of the site.
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- 2023
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3. VALIDATION OF THE RUMINATIVE RESPONSES SCALE ON THE ROMANIAN POPULATION – GENDER DIFFERENCES IN RUMINATING RESPONSES
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Cătălin LAZĂR, Cornelia RADA, Cristian-Nicolae CONSTANTIN, and Camelia POPA
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rumination ,depression ,gender ,brooding ,reflection ,Geography. Anthropology. Recreation ,Anthropology ,GN1-890 - Abstract
Objectives. The objectives of the study were to develop the Romanian version of the RRS-22 Ruminative Response Scale, thus initiating the process of validating it and exploring gender differences in ruminative-depressive responses with the help of this instrument. Material and methods. The scale was translated by two English translators. The two variants were compared in order to preserve the semantic content of the items, and the Romanian version of the scale was finalized. Subsequently, the scale was applied to N = 372 participants. Exploratory and confirmatory factor analyses were performed, and internal consistency, convergent validity, and divergent validity were assessed. Gender differences in ruminative-depressive responses were explored. Results. The criteria required to validate the RRS instrument for the Romanian population have been satisfied. The scales associated with the three latent factors showed satisfactory internal consistency. Its use revealed significant differences between women and men, in favor of women, both in terms of total rumination scores and in terms of the reflection and brooding factor scores. There were also highly significant differences between women and men regarding ruminative themes assessed by the RRS-22. Conclusions. The Romanian version of the RRS-22 scale proved to have good psychometric properties. Its application confirmed the results of international studies carried out with the help of this instrument, according to which there are important differences between women and men in the way of coping with a negative mood, expressed through ruminative responses. The tendency to engage in rumination in response to distress is much more pronounced in women.
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- 2024
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4. Non-Destructive Textural Characterization of Southern Romanian Neolithic and Chalcolithic Pottery Using Digital Image Analysis on Tomographically Reconstructed Sections
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Daniel Stoicescu, Octavian G. Duliu, Vasile Opriş, Bogdan Manea, Izabela Mariş, Valentina Voinea, Pavel Mirea, Valentin Parnic, Mădălina Dimache, and Cătălin Lazăr
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Balkan ,Neolithic ,pottery ,archaeometry ,X-rays ,image analysis ,Archaeology ,CC1-960 - Abstract
Pottery is a complex archaeological material that is found ubiquitously in various spatial—temporal frameworks from all over the world; therefore, it is of great importance to archaeological research. The current paper aims to present and discuss the results obtained on a batch of Neolithic (ca. 6000–5000 BC) and Chalcolithic (ca. 5000–3900 BC) pottery sherds from Southern Romania through X-ray Computed Tomography, a non-destructive methodology that allows for the 3D reconstruction and precise measurement of inclusions and voids present within ceramic artefacts. Images from several potsherds were subsequently exported and analyzed by means of dedicated software (ImageJ 1.54p and GIMP) to extract quantitative information on the observed features. Grain size and morphometric analyses were performed on the particles, while the contour variability of the examined inclusions was characterized through the application of shape descriptors. Voids were analyzed in order to reveal specific orientation patterns through the examination of the aspect ratio of the holes and of the Rayleigh z test values. These analyses evidenced the general reliance of moderately and poorly sorted clays for ceramic production, accompanied by a gradual transition from organic to grog tempering, while conservative traditions remained prevalent in primary pottery-forming processes.
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- 2023
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5. Unravelling the resilience of the KGK VI population from the Gumelnița site (Romania) through stable isotopes
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Ana García-Vázquez, Adrian Bălășescu, Gabriel Vasile, Mihaela Golea, Valentin Radu, Vasile Opriș, Theodor Ignat, Mihaela Culea, Cristina Covătaru, Gabriela Sava, and Cătălin Lazăr
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Medicine ,Science - Abstract
Abstract The Gumelnița site belongs to the Kodjadermen-Gumelnița-Karanovo VI (KGK VI) communities (c. 4700–3900 cal BC) and comprises the tell-type settlement and its corresponding cemetery. This paper reconstructs the diet and lifeways of the Chalcolithic people in the northeastern Balkans using archaeological remains found at the Gumelnița site (Romania). A multi-bioarchaeological investigation (archaeobotany, zooarchaeology, anthropology) was conducted on vegetal, animal, and human remains, alongside radiocarbon dating and stable isotope analyses (δ13C, δ15N) of humans (n = 33), mammals (n = 38), reptiles (n = 3), fishes (n = 8), freshwater mussels shells (n = 18), and plants (n = 24). According to the results of δ13C and δ15N values and FRUITS, the inhabitants of Gumelnița had a diet based on crops and using natural resources, such as fish, freshwater molluscs and game. Although domestic fauna was occasionally exploited for meat, it had a role in providing secondary products. Crops were heavily manured, and chaff and other crop waste may have been necessary fodder for cattle and sheep. Dogs and pigs fed on human waste, although the diet of the latter is more similar to that of wild boars. Foxes had a diet close to dogs, which may indicate synanthropic behaviour. Radiocarbon dates were calibrated with the percentage of freshwater resources obtained by FRUITS. As a result, the corrected dates for the freshwater reservoir effect (FRE) have a delay of an average of 147 years. According to our data, this agrarian community developed a subsistence strategy under the pressure of some climatic changes that started after 4300 cal BC, corresponding to KGK VI rapid collapse/decline episode tracked recently (that begins around 4350 cal BC). This matching of our data in the two models (climatic and chrono-demographic) allowed us to capture the economic strategies that led to the resilience of those people more than other contemporary KGK VI communities.
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- 2023
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6. THE INFLUENCE OF GENOTYPE, SOIL TILLAGE AND FERTILISATION ON CARBON SEQUESTRATION IN MAIZE
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Elena PETCU, Cătălin LAZĂR, Elena PARTAL, Laura CONŢESCU, and Daniela HORHOCEA
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maize ,carbon sequestration ,hybrids ,soil tillage ,fertilisation ,Environmental sciences ,GE1-350 ,Agriculture - Abstract
The increase in the concentration of greenhouse gases in the Earth’s atmosphere, especially that of CO2, is a major concern because it is the main source leading to global warming, and its impact on climate change is still widely studied. The intensity and frequency of drought and flooding increase due to the change in climate, which has a negative impact on crop productivity and food security. The aim of this paper was to demonstrate the role of corn in carbon sequestration based on plant biomass and soil organic carbon accumulation. We presented the main factors that contribute to carbon sequestration and concrete examples regarding the capacity of corn hybrids created at National Agricultural Research and Development Institute (NARDI) Fundulea, as well as aspects regarding the importance of soil tillage and fertilisation. In contrast to genotypes in which this ratio was lower, maize genotypes that demonstrated a rise in the root:stem ratio under drought stress conditions produced more biomass, suggesting that the roots of these genotypes can grow at water potentials where stem growth is inhibited, which are attributes that also prove their good potential for carbon sequestration under climate change conditions. The organic carbon content in the superficial soil layer decreased with the intensification of the degree of soil mobilisation (9.95% when working the soil with the chisel, 17.91% for ploughing), but fertilisation had a beneficial effect. The biomass was higher than that of the unfertilised soil. This means that a higher carbon input has a positive influence on the carbon stock in the soil.
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- 2023
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7. PIXE and XRF analyses of copper artifacts from the Gumelniţa area (Romania)
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Adelina-Elena Darie, Dragoș-Alexandru Mirea, Valentin Parnic, and Cătălin Lazăr
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Northern Balkans ,Copper Age ,Gumelniţa ,copper artifacts ,elemental analyses ,Prehistoric archaeology ,GN700-890 - Abstract
The main aim of this research is to expand the knowledge of the early stages of copper metallurgy in the Chalcolithic within the Gumelniţa communities through compositional analyses (PIXE, XRF) performed on a group of copper objects that originated from several sites belonging to Kodzhadermen–Gumelniţa–Karanovo VI (KGK VI) communities in southeast Romania (Chitila–Fermă, Măriuța, Sultana–Malu Roșu, Sărulești, and Vidra). All analyses were performed at the Horia Hulubei National Institute for Research & Development in Physics and Nuclear Engineering (Romania), and the investigated items belong to the collections of the Lower Danube Museum in Călărași and the Bucharest Municipality Museum. The resulting data were used as a starting point of a discussion on the possible prehistoric copper sources used by prehistoric people to manufacture the analyzed artifacts.
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- 2022
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8. Between Object and Subject
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Vasile Opriș, Bogdan Manea, Mircea Lechintan, Roxana Bugoi, Florin Constantin, Theodor Ignat, and Catalin Lazar
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Balkans ,Eneolithic ,anthropomorphic pot ,CT scans ,technological analysis ,experimental archaeology ,Archaeology ,CC1-960 - Abstract
The current paper aims to reveal the potential of combining multiple approaches (techno-functional analysis, experimental archaeology, and X-ray Computed Tomography) when it comes to studying unique earthenware artefacts, such as the prehistoric human-shaped pot discovered within the tell settlement from Sultana-Malu Rosu (Romania), that belongs to the Kodjadermen-Gumelnita-Karanovo VI civilization (KGK VI) which thrived during the 5th millennium BC. This human-shaped pot, also known as ‘The Goddess of Sultana’, is an emblematic artefact that fascinates with its shape, gestures, and decoration. It was apparently made from a standard clay paste recipe and using basic forming techniques, with little care for the internal surface. This vessel also has several hidden cracks and some manipulation traces on its backside. In order to explore its relevance, our approach to this particular human-shaped pot included the use of archaeological data in correlation with other techniques in order to decipher the manufacturing process for such vessels, the possible way of using them, but also the meanings that they might have had for past human communities.
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- 2022
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9. Human Impact Scale on the Preservation of Archaeological Sites from Mostiştea Valley (Romania)
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Cristina Covătaru, Cornelis Stal, Mihai Florea, Ionela Opriș, Corina Simion, Ileana Rădulescu, Romeo Călin, Theodor Ignat, Cristina Ghiță, and Cătălin Lazăr
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Mostiștea Valley ,landscape changes ,GIS ,cultural heritage modification ,geomorphological evolution ,anthropic impact ,Environmental sciences ,GE1-350 - Abstract
Through time, both natural and cultural heritage have unfortunately been under threat due to multiple environmental and human-induced factors, which are likely to trigger various hazards such as soil erosion, landslides, or land collapse. The analysis of old cartographic material, aerial imagery, and satellite imagery has been used in multiple studies to observe and understand the changes that archaeological sites have undergone over the last centuries. These efforts are intended, among other things, to raise awareness of the threats affecting cultural heritage and prevent damages and preserve tangible evidence of the distant past. In this study, historical maps and satellite imagery were analyzed to observe how the landscape in the Mostiștea Valley (Romania) has been used over the last 230 years and how the land use has affected the cultural heritage. Land cover and land use (LCLU) changes in the Mostiștea Valley have occurred due to numerous natural and anthropic forces. These changes have resulted in the damage of tangible heritage in the area with varying degrees of intensity. The results of this study allow the quantification of the magnitude of these changes and their impact on different sites in the region.
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- 2022
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10. Efficient cellular and humoral immune response and production of virus-neutralizing antibodies by the Hepatitis B Virus S/preS116-42 antigen
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Ana-Maria Pantazica, Mihaela-Olivia Dobrica, Catalin Lazar, Cristina Scurtu, Catalin Tucureanu, Iuliana Caras, Irina Ionescu, Adriana Costache, Adrian Onu, Jihong Liu Clarke, Crina Stavaru, and Norica Branza-Nichita
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HBV ,vaccine design ,SVP ,antigens ,chimeric proteins ,adjuvants ,Immunologic diseases. Allergy ,RC581-607 - Abstract
Despite the availability of improved antiviral therapies, infection with Hepatitis B virus (HBV) remains a3 significant health issue, as a curable treatment is yet to be discovered. Current HBV vaccines relaying on the efficient expression of the small (S) envelope protein in yeast and the implementation of mass vaccination programs have clearly contributed to containment of the disease. However, the lack of an efficient immune response in up to 10% of vaccinated adults, the controversies regarding the seroprotection persistence in vaccine responders and the emergence of vaccine escape virus mutations urge for the development of better HBV immunogens. Due to the critical role played by the preS1 domain of the large (L) envelope protein in HBV infection and its ability to trigger virus neutralizing antibodies, including this protein in novel vaccine formulations has been considered a promising strategy to overcome the limitations of S only-based vaccines. In this work we aimed to combine relevant L and S epitopes in chimeric antigens, by inserting preS1 sequences within the external antigenic loop of S, followed by production in mammalian cells and detailed analysis of their antigenic and immunogenic properties. Of the newly designed antigens, the S/preS116–42 protein assembled in subviral particles (SVP) showed the highest expression and secretion levels, therefore, it was selected for further studies in vivo. Analysis of the immune response induced in mice vaccinated with S/preS116–42- and S-SVPs, respectively, demonstrated enhanced immunogenicity of the former and its ability to activate both humoral and cellular immune responses. This combined activation resulted in production of neutralizing antibodies against both wild-type and vaccine-escape HBV variants. Our results validate the design of chimeric HBV antigens and promote the novel S/preS1 protein as a potential vaccine candidate for administration in poor-responders to current HBV vaccines.
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- 2022
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11. Early Sowing on Some Soybean Genotypes under Organic Farming Conditions
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Victor Petcu, Ancuța Bărbieru, Mihaela Popa, Cătălin Lazăr, Laurențiu Ciornei, Amalia Gianina Străteanu, and Ioana Claudia Todirică
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organic ,soybean ,early sowing ,Romania ,plant density ,cumulative stress index ,Botany ,QK1-989 - Abstract
The demand for soybeans in Europe motivates breeders, researchers, and growers to find suitable cultivars to adapt and extend the soybean crop to improper climate areas. Weed control is a crucial aspect of crop technology in organic agriculture, but particularly for soybean crops. In laboratory conditions, the cumulative stress index for seedlings was determined to identify the susceptible cultivars. A field experiment with 14 soybean accessions and 2 sowing dates was conducted under organic farming conditions over the course of three years, from 2020 to 2022. Plant population density was found to be significantly (p < 0.01 and p < 0.1) negatively correlated to the degree of resistance to low temperature as well as infestation degree with weeds (for p < 0.05 and p < 0.1), with the exception of early sowing in 2021. Yield was significantly (p < 0.05, p < 0.01, p < 0.1) correlated with plant population density, with the exception of optimal sowing in 2022. Early sowing variants emerged with vigor in the first two years, breeding lines and registered varieties showed low input, and organic agriculture systems showed low yields in the drought years of 2020 and 2022. Although early sowing even in the first two years proved to be a practice that increased the cultivars’ performance, in 2022, due to the long period of chilling stress in the field, this option had negative effects on yield due to the high weed frequency. Therefore, the early sowing strategy for the soybean crop in this particular case of non-irrigated conditions in a temperate continental area proved to be a risky practice.
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- 2023
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12. Stable isotope data of Neolithic and Eneolithic populations in the Balkans, 6600 to 4000 BC
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Aurélien Tafani, Cătălin Lazăr, and Robert H. Tykot
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Collagen (bone and dentine) ,Tooth enamel ,Carbon ,Nitrogen ,Neolithic ,Eneolithic ,Computer applications to medicine. Medical informatics ,R858-859.7 ,Science (General) ,Q1-390 - Abstract
Stable isotopic ratios of carbon and nitrogen performed on collagen and tooth enamel offer invaluable insight into the diet of ancient populations. In the northern Balkans, most of these isotopic data have been collected as auxiliary information of radiocarbon dates, to correct a potential marine reservoir effect. In order to facilitate the access of the academic community to these data, we present a set of isotopic carbon and nitrogen ratios of human collagen samples for 188 individuals from 12 previously published sites together with hitherto unreleased data for 24 individuals from 4 sites from the Neolithic and Eneolithic period in Bulgaria and Romania. This collection also includes previously published carbon isotopic ratio measurements on tooth enamel of 34 individuals.
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- 2022
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13. Looking beyond appearances: a multi-analytical approach on the prehistoric clay weights
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Bogdan Manea, Mircea Lechintan, Gabriel Popescu, Theodor Ignat, Vasile Opriş, Florin Constantin, Mădălina Dimache, Valentin Parnic, Roxana Bugoi, and Cătălin Lazăr
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Southern Romania ,Neolithic ,Clay weights ,X-ray CT scan ,Experimental archaeology ,Fine Arts ,Analytical chemistry ,QD71-142 - Abstract
Abstract In this paper we analyzed a batch of 64 clay weights from three archaeological sites located in Romania (Gumelniţa, Măgura-Jilava, and Sultana) that belong to Kodjadermen-Gumelniţa-Karanovo VI cultural complex (4600–3900 cal. BC). Our approach includes an interdisciplinary investigation based on technological analysis, experimental archaeology, and X-ray CT scans coupled with statistical analysis. This investigation has a high potential to reveal relevant information regarding the technological background (e.g., inclusion, voids, temper, etc.), manufacturing stages (e.g., modeling, shaping, kneading, etc.), or transformation processes (e.g., drying and firing vs. weight and size modification) in order to identify, explain and understand the chaîne operatoire for this type of artefacts. Moreover, correlation of the results with the experimental archaeology could offer an integrative interpretation about the material culture of past humans and its multiple meanings, but also critical information about the multiple dimensions of manufacture for these objects (e.g., time, effort, physical–chemical processes, etc.). The multi-analytical approach proposed here also includes a comparative study of technological aspects of these clay weights across the three archaeological sites investigated, as well as the experimental replicas.
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- 2019
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14. Supporting Long-Term Archaeological Research in Southern Romania Chalcolithic Sites Using Multi-Platform UAV Mapping
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Cornelis Stal, Cristina Covataru, Johannes Müller, Valentin Parnic, Theodor Ignat, Robert Hofmann, and Catalin Lazar
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southeastern Europe ,Chalcolithic ,archaeological sites ,UAV ,spatial data ,Motor vehicles. Aeronautics. Astronautics ,TL1-4050 - Abstract
Spatial data play a crucial role in archaeological research, and orthophotos, digital elevation models, and 3D models are frequently used for the mapping, documentation, and monitoring of archaeological sites. Thanks to the availability of compact and low-cost uncrewed airborne vehicles, the use of UAV-based photogrammetry matured in this field over the past two decades. More recently, compact airborne systems are also available that allow the recording of thermal data, multispectral data, and airborne laser scanning. In this article, various platforms and sensors are applied at the Chalcolithic archaeological sites in the Mostiștea Basin and Danube Valley (Southern Romania). By analysing the performance of the systems and the resulting data, insight is given into the selection of the appropriate system for the right application. This analysis requires thorough knowledge of data acquisition and data processing, as well. As both laser scanning and photogrammetry typically result in very large amounts of data, a special focus is also required on the storage and publication of the data. Hence, the objective of this article is to provide a full overview of various aspects of 3D data acquisition for UAV-based mapping. Based on the conclusions drawn in this article, it is stated that photogrammetry and laser scanning can result in data with similar geometrical properties when acquisition parameters are appropriately set. On the one hand, the used ALS-based system outperforms the photogrammetric platforms in terms of operational time and the area covered. On the other hand, conventional photogrammetry provides flexibility that might be required for very low-altitude flights, or emergency mapping. Furthermore, as the used ALS sensor only provides a geometrical representation of the topography, photogrammetric sensors are still required to obtain true colour or false colour composites of the surface. Lastly, the variety of data, such as pre- and post-rendered raster data, 3D models, and point clouds, requires the implementation of multiple methods for the online publication of data. Various client-side and server-side solutions are presented to make the data available for other researchers.
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- 2022
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15. N-Glycosylation and N-Glycan Processing in HBV Biology and Pathogenesis
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Mihaela-Olivia Dobrica, Catalin Lazar, and Norica Branza-Nichita
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HBV ,glycosylation ,folding ,vaccine ,immune response ,HCC ,Cytology ,QH573-671 - Abstract
Hepatitis B Virus (HBV) glycobiology has been an area of intensive research in the last decades and continues to be an attractive topic due to the multiple roles that N-glycosylation in particular plays in the virus life-cycle and its interaction with the host that are still being discovered. The three HBV envelope glycoproteins, small (S), medium (M) and large (L) share a very peculiar N-glycosylation pattern, which distinctly regulates their folding, degradation, assembly, intracellular trafficking and antigenic properties. In addition, recent findings indicate important roles of N-linked oligosaccharides in viral pathogenesis and evasion of the immune system surveillance. This review focuses on N-glycosylation’s contribution to HBV infection and disease, with implications for development of improved vaccines and antiviral therapies.
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- 2020
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16. Ancient DNA from South-East Europe Reveals Different Events during Early and Middle Neolithic Influencing the European Genetic Heritage.
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Montserrat Hervella, Mihai Rotea, Neskuts Izagirre, Mihai Constantinescu, Santos Alonso, Mihai Ioana, Cătălin Lazăr, Florin Ridiche, Andrei Dorian Soficaru, Mihai G Netea, and Concepcion de-la-Rua
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Medicine ,Science - Abstract
The importance of the process of Neolithization for the genetic make-up of European populations has been hotly debated, with shifting hypotheses from a demic diffusion (DD) to a cultural diffusion (CD) model. In this regard, ancient DNA data from the Balkan Peninsula, which is an important source of information to assess the process of Neolithization in Europe, is however missing. In the present study we show genetic information on ancient populations of the South-East of Europe. We assessed mtDNA from ten sites from the current territory of Romania, spanning a time-period from the Early Neolithic to the Late Bronze Age. mtDNA data from Early Neolithic farmers of the Starčevo Criş culture in Romania (Cârcea, Gura Baciului and Negrileşti sites), confirm their genetic relationship with those of the LBK culture (Linienbandkeramik Kultur) in Central Europe, and they show little genetic continuity with modern European populations. On the other hand, populations of the Middle-Late Neolithic (Boian, Zau and Gumelniţa cultures), supposedly a second wave of Neolithic migration from Anatolia, had a much stronger effect on the genetic heritage of the European populations. In contrast, we find a smaller contribution of Late Bronze Age migrations to the genetic composition of Europeans. Based on these findings, we propose that permeation of mtDNA lineages from a second wave of Middle-Late Neolithic migration from North-West Anatolia into the Balkan Peninsula and Central Europe represent an important contribution to the genetic shift between Early and Late Neolithic populations in Europe, and consequently to the genetic make-up of modern European populations.
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- 2015
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17. Comparative proteomics reveals novel components at the plasma membrane of differentiated HepaRG cells and different distribution in hepatocyte- and biliary-like cells.
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Catalina Petrareanu, Alina Macovei, Izabela Sokolowska, Alisa G Woods, Catalin Lazar, Gabriel L Radu, Costel C Darie, and Norica Branza-Nichita
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Medicine ,Science - Abstract
Hepatitis B virus (HBV) is a human pathogen causing severe liver disease and eventually death. Despite important progress in deciphering HBV internalization, the early virus-cell interactions leading to infection are not known. HepaRG is a human bipotent liver cell line bearing the unique ability to differentiate towards a mixture of hepatocyte- and biliary-like cells. In addition to expressing metabolic functions normally found in liver, differentiated HepaRG cells support HBV infection in vitro, thus resembling cultured primary hepatocytes more than other hepatoma cells. Therefore, extensive characterization of the plasma membrane proteome from HepaRG cells would allow the identification of new cellular factors potentially involved in infection. Here we analyzed the plasma membranes of non-differentiated and differentiated HepaRG cells using nanoliquid chromatography-tandem mass spectrometry to identify the differences between the proteomes and the changes that lead to differentiation of these cells. We followed up on differentially-regulated proteins in hepatocytes- and biliary-like cells, focusing on Cathepsins D and K, Cyclophilin A, Annexin 1/A1, PDI and PDI A4/ERp72. Major differences between the two proteomes were found, including differentially regulated proteins, protein-protein interactions and intracellular localizations following differentiation. The results advance our current understanding of HepaRG differentiation and the unique properties of these cells.
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- 2013
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18. Activation of ERAD pathway by human hepatitis B virus modulates viral and subviral particle production.
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Catalin Lazar, Alina Macovei, Stefana Petrescu, and Norica Branza-Nichita
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Medicine ,Science - Abstract
Hepatitis B virus (HBV) belongs to the Hepadnaviridae family of enveloped DNA viruses. It was previously shown that HBV can induce endoplasmic reticulum (ER) stress and activate the IRE1-XBP1 pathway of the unfolded protein response (UPR), through the expression of the viral regulatory protein X (HBx). However, it remained obscure whether or not this activation had any functional consequences on the target genes of the UPR pathway. Of these targets, the ER degradation-enhancing, mannosidase-like proteins (EDEMs) are thought to play an important role in relieving the ER stress during UPR, by recognizing terminally misfolded glycoproteins and delivering them to the ER-associated degradation (ERAD). In this study, we investigated the role of EDEMs in the HBV life-cycle. We found that synthesis of EDEMs (EDEM1 and its homologues, EDEM2 and EDEM3) is significantly up-regulated in cells with persistent or transient HBV replication. Co-expression of the wild-type HBV envelope proteins with EDEM1 resulted in their massive degradation, a process reversed by EDEM1 silencing. Surprisingly, the autophagy/lysosomes, rather than the proteasome were involved in disposal of the HBV envelope proteins. Importantly, inhibition of the endogenous EDEM1 expression in HBV replicating cells significantly increased secretion of both, enveloped virus and subviral particles. This is the first report showing that HBV activates the ERAD pathway, which, in turn, reduces the amount of envelope proteins, possibly as a mechanism to control the level of virus particles in infected cells and facilitate the establishment of chronic infections.
- Published
- 2012
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