936 research outputs found

    The Marmara Sea Gateway since ~16 ky BP: non-catastrophic causes of paleoceanographic events in the Black Sea at 8.4 and 7.15 ky BP

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    The Late Quaternary history of connection of the Black Sea to the Eastern Mediterranean has been intensely debated. Ryan, Pitman and coworkers advocate two pulses of outflow from the Black Sea to the world ocean at ~16–14.7 ky BP and ~11–10 ky BP. From ~14.7–11 ky BP and from ~10–8.4 ky BP, they suggest that the level of the Black Sea fell to ~ -100 m. At 8.4 ky BP, they further claim that a catastrophic flood occurred in a geological instant, refilling the Black Sea with saline waters from the Mediterranean. In contrast, we continue to gather evidence from seismic profiles and dated cores in the Marmara Sea which demonstrate conclusively that the proposed flood did not occur. Instead, the Black Sea has been at or above the Bosphorus sill depth and flowing into the world ocean unabated since ~10.5 ky BP. This conclusion is based on continuous Holocene water-column stratification (leading to sapropel deposition in the Marmara Sea and the Aegean Sea), proxy indicators of sea-surface salinity, and migration of endemic species across the Bosphorus in both directions whenever appropriate hydrographic conditions existed in the strait. The two pulses of outflow documented by Ryan, Pitman and coworkers find support in our data, and we have modified our earlier interpretations so that these pulses now coincide with the development of mid-shelf deltas: \Delta 2 (16–14.7 ky BP) and \Delta 1 (10.5–9 ky BP) at the southern end of the Bosphorus Strait. However, continued Black Sea outflow after 9 ky BP prevented the northward advection of Mediterranean water and the entry of open-marine species into the Black Sea for more than 1000 years. Sufficient Mediterranean water to change the Sr-isotopic composition of slope and shelf water masses was not available until ~8.4 ky BP (along with the first arrival of many varieties of marine fauna and flora), whereas euryhaline molluscs did not successfully populate the Black Sea shelves until ~7.15 ky BP. Instead of relying on catastrophic events, we recognize a slow, progressive reconnection of the Black Sea to the world ocean, accompanied by significant time lags

    Macroanatomical and histological study of the structure of intercornual gland in Abaza (Capra Aegagrus) and Gurcu (Capra Falconeri) goats breeds

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    Background: The anatomical localisation of the odour glands, which increase activity during the reproduction period and help goat species to find each other, varies. Materials and methods: In our study, the anatomical and histological structures of the glands around the horn were examined in the Gurcu and Abaza goats, which are native breeds. In this study a total of 12 Abaza and Gurcu goat heads were used. Results: The area between the two horns and area at the back of the horns were shaved to remove all hair. The distance between the horns of both goat breeds was measured using an electronic calliper. The mean distance between the horns of the Abaza goats was determined as 36.80 ± 8.62 mm while this distance was 39.63 ± 4.10 mm for the Gurcu goats. Gland tissue that could not be seen anatomically under the skin was examined histologically. For the histological examination, skin samples were taken from the anterior, middle, right posterior and left posterior of the area between the two horns of both breeds. Crossman triple staining and haematoxylin and eosin staining were applied to the samples. Conclusions: Glandula intercornualis was found to be slightly caudal between the horns in both breeds and normal sebaceous glands were almost absent in the areas where these glands were found. Lobes and branched alveolar glands were located around the hair follicles

    The arterial anatomy of the saphenous flap: a cadaveric study

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    The saphenous flap is a fasciocutaneous flap generally used for knee and upper third of the leg coverage. Due to various descriptions of the saphenous flap, such as venous, sensory, and free flap, the origin and distributing characteristics of the saphenous artery are important for plastic surgeons. The aim of this cadaveric study was to evaluate the anatomical features of the saphenous flap. The pedicles of the saphenous flap were dissected under 4 x loop magnification in thirty-two legs of 16 formalin-fixed adult cadavers. The findings of this anatomic study were as follows: Descending genicular artery originated from the femoral artery in all of the cases. The first musculoarticular branch, which arose from descending genicular, to the vastus medialis muscle existed in all dissections. The second branch was the saphenous artery which seperately originated from the descending genicular artery in all of the cases. At the level of origin the mean diameter of the saphenous artery was found to be 1.61 mm. The muscular branches to the anterior or posterior sides of the sartorious muscle existed in all of the dissections. Two vena comitantes and a saphenous nerve were accompanying the saphenous artery in all cadavers. The mean distance between the origin of the artery and interepicondylar line of tibia was 115 mm. The muscular branches of the saphenous artery to the gracilis muscle were encountered 6.66% of the cases. The cutaneous branches numbered between one and four, and arose 3.5 to 9.5 cm from the site of origin of the saphenous artery. The distal end of the saphenous artery reached approximately 122 mm distally to the knee joint in all cases. Due to variations of the arterial anatomy and limited number of anatomic studies of the saphenous flap, we studied the topography and anatomy of the saphenous artery for increasing reliability of the saphenous flap

    Silica material variation for the Mn<sub>x</sub>O<sub>y</sub>-Na<sub>2</sub>WO<sub>4</sub>/SiO<sub>2</sub>

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    The oxidative coupling of methane (OCM) is one of the best methods for the direct conversion of methane.Among the known OCM catalysts, MnxOy-Na2WO4/SiO2 is a promising candidate for an industrial appli-cation, showing a high methane conversion and C2 selectivity, with a good stability during long-termcatalytic activity tests. In the present study, some results have been already published and discussedbriefly in our previous short communication. However, we herein investigated comprehensively theinfluence of various silica support materials on the performance of the MnxOy-Na2WO4/SiO2 systemin the OCM by means of ex situ and in situ XRD, BET, SEM and TEM characterization methods andshowed new results to reveal possible support effects on the catalyst. The catalytic performance of most MnxOy-Na2WO4/SiO2 catalysts supported by different silica support materials did not differ substan-tially. However, the performance of the SBA-15 supported catalyst was outstanding and the methaneconversion was nearly twofold higher in comparison to the other silica supported catalysts at similar C2 selectivity as shown before in the communication. The reason of this substantial increase in performancecould be the ordered mesoporous structure of the SBA-15 support material, homogeneous dispersion ofactive components and high number of active sites responsible for the OCM

    Effect of exogenous GnRH at the time of artificial insemination on reproductive performance of awassi ewes synchronized with progestagen-PMSG-PGF2α combination

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    This study was carried out to investigate the efficacy of PGF2a for oestrus synchronization (ES) in Awassi ewes to which were administered the progestagen–PMSG combination, and to evaluate the effect of the exogenous GnRH administration immediately after the artificial insemination (AI) on their pregnancy rate and lambing performance during the breeding season. The ewes (n ¼ 33) were treated with an intravaginal sponge impregnated with 30 mg fluorogestane acetate for 12 days and were injected with 500 IU PMSG at the time of removal of the sponge. The ewes were then divided into three equal groups of 11 ewes each. One millilitre of physiological saline (0.9% NaCl; placebo) was administered to each ewe in Group 1 at the time of second AI. Approximately 4 lg GnRH (busereline) was injected to each ewe in Group 2 immediately after second AI. A total of 150 lg PGF2a (cloprostenole) was injected at the time of sponge removal on day 12 and 4 lg GnRH immediately after the second AI was also treated to each ewe in Group 3. Intracervical AI with diluted fresh semen was performed twice at 12 and 24 h following the onset of oestrus. The injection-oestrus onset and injection-oestrus-end interval in Group 3 was significantly (p < 0.001) shorter than both Groups 1 and 2. Although the pregnancy rates of Groups 2 and 3 (81.8%; 9/11) were numerically higher than of Group 1 (63.6%; 7/11), the difference among the groups was statistically insignificant. The multiple birth rate of Group 3 was found higher than Groups 1 and 2. However, the number of single lambs of Group 1 was also higher than Groups 2 and 3 (p < 0.05). Despite the litter sizes of Groups 2 (1.27; 14/11) and 3 (1.55; 17/11) being numerically higher than Group 1 (0.73; 8/11), the differences among all the groups were statistically insignificant. In conclusion, the administration of PGF2a at the time of removal of the sponge shortens the injection oestrus-onset and oestrus-end interval in Awassi ewes treated with progestagen–PMSG. Additionally, exogenous GnRH treatment immediately after the AI increases the multiple birth rate of Awassi ewes synchronized with progestagen– PMSG–PGF2a combination

    Divergent in situ expression of IL-31 and IL-31RA between bullous pemphigoid and pemphigus vulgaris

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    Bullous pemphigoid (BP) and pemphigus vulgaris (PV) are two major autoimmune blistering skin diseases. Unlike PV, BP is accompanied by intense pruritus, suggesting possible involvement of the pruritogenic cytokine IL-31. However, the underlying mechanisms of the clinical difference between BP and PV in terms of pruritus are not fully understood. To compare the expression levels of IL-31 and its receptor IL-31RA in the lesional skin, including peripheral nerves in BP and PV patients, immunohistochemical staining for IL-31 and IL-31RA was performed in skin samples of BP and PV patients and healthy controls (HC). The IL-31RA-expressing area in epidermis and peripheral nerves was analysed using ImageJ and the percentage of positive cells for IL-31/IL-31RA in dermal infiltrating cells was manually quantified. Quantitative analyses revealed that IL-31/IL-31RA expressions in the epidermis and dermal infiltrate were significantly increased in BP compared to PV and HC. The difference between BP and PV became more obvious when advanced bullous lesions were compared. Peripheral nerves in BP lesions presented significantly higher IL-31RA expression compared to PV lesions. In conclusion, we found significantly augmented expressions of IL-31/IL-31RA in BP lesions, including peripheral nerves, in comparison to PV. These results suggest a possible contribution of IL-31/IL-31RA signalling to the difference between BP and PV in the facilitation of pruritus and local skin inflammation, raising the possibility of therapeutic targeting of the IL-31/IL-31RA pathway in BP patients

    Computational Identification and Analysis of the Key Biosorbent Characteristics for the Biosorption Process of Reactive Black 5 onto Fungal Biomass

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    The performances of nine biosorbents derived from dead fungal biomass were investigated for their ability to remove Reactive Black 5 from aqueous solution. The biosorption data for removal of Reactive Black 5 were readily modeled using the Langmuir adsorption isotherm. Kinetic analysis based on both pseudo-second-order and Weber-Morris models indicated intraparticle diffusion was the rate limiting step for biosorption of Reactive Black 5 on to the biosorbents. Sorption capacities of the biosorbents were not correlated with the initial biosorption rates. Sensitivity analysis of the factors affecting biosorption examined by an artificial neural network model showed that pH was the most important parameter, explaining 22%, followed by nitrogen content of biosorbents (16%), initial dye concentration (15%) and carbon content of biosorbents (10%). The biosorption capacities were not proportional to surface areas of the sorbents, but were instead influenced by their chemical element composition. The main functional groups contributing to dye sorption were amine, carboxylic, and alcohol moieties. The data further suggest that differences in carbon and nitrogen contents of biosorbents may be used as a selection index for identifying effective biosorbents from dead fungal biomass

    Neutralization of SARS-CoV-2 by highly potent, hyperthermostable, and mutation-tolerant nanobodies

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    Monoclonal anti-SARS-CoV-2 immunoglobulins represent a treatment option for COVID-19. However, their production in mammalian cells is not scalable to meet the global demand. Single-domain (VHH) antibodies (also called nanobodies) provide an alternative suitable for microbial production. Using alpaca immune libraries against the receptor-binding domain (RBD) of the SARS-CoV-2 Spike protein, we isolated 45 infection-blocking VHH antibodies. These include nanobodies that can withstand 95°C. The most effective VHH antibody neutralizes SARS-CoV-2 at 17–50 pM concentration (0.2–0.7 µg per liter), binds the open and closed states of the Spike, and shows a tight RBD interaction in the X-ray and cryo-EM structures. The best VHH trimers neutralize even at 40 ng per liter. We constructed nanobody tandems and identified nanobody monomers that tolerate the K417N/T, E484K, N501Y, and L452R immune-escape mutations found in the Alpha, Beta, Gamma, Epsilon, Iota, and Delta/Kappa lineages. We also demonstrate neutralization of the Beta strain at low-picomolar VHH concentrations. We further discovered VHH antibodies that enforce native folding of the RBD in the E. coli cytosol, where its folding normally fails. Such “fold-promoting” nanobodies may allow for simplified production of vaccines and their adaptation to viral escape-mutations

    Robustness of massively parallel sequencing platforms

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    The improvements in high throughput sequencing technologies (HTS) made clinical sequencing projects such as ClinSeq and Genomics England feasible. Although there are significant improvements in accuracy and reproducibility of HTS based analyses, the usability of these types of data for diagnostic and prognostic applications necessitates a near perfect data generation. To assess the usability of a widely used HTS platform for accurate and reproducible clinical applications in terms of robustness, we generated whole genome shotgun (WGS) sequence data from the genomes of two human individuals in two different genome sequencing centers. After analyzing the data to characterize SNPs and indels using the same tools (BWA, SAMtools, and GATK), we observed significant number of discrepancies in the call sets. As expected, the most of the disagreements between the call sets were found within genomic regions containing common repeats and segmental duplications, albeit only a small fraction of the discordant variants were within the exons and other functionally relevant regions such as promoters. We conclude that although HTS platforms are sufficiently powerful for providing data for first-pass clinical tests, the variant predictions still need to be confirmed using orthogonal methods before using in clinical applications. © 2015 Kavak et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
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