207 research outputs found

    Seasonal variation of the cold intermediate water in the Southwestern Black Sea and its interaction with the Sea of Marmara during the period of 1996-1998

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    Seasonal variations of the cold intermediate water (CIW) in the southwestern Black Sea and its entrance into the Strait of Istanbul (Bosphorus) within the upper layer flow have been studied by using monthly oceanographic data sets collected in 1996-1998 period. In addition, the advection of the CIW via Strait Of Istanbul to the Sea of Marmara has been investigated.The CIW is a permanent and characteristic water mass of the Black Sea, markedly observed in the northwestern Black Sea. It is transported with the Rim Current along the boundary of the basin. The average temperature of the CIW is about 6o C. The 8oC isotherms defines its upper and lower boundaries. The upper boundary of CIW rises up to the 20 m depth in the shelf and coastal upwelling regions with a thickness of 40 m. On the other hand, the depth of the upper boundary may decrease down to 40 m with a thickness of 120 m in the anticyclonic regions.The CIW, located between 30 and 65m depths, was observed from April to September at the northern approaches of the Strait of Istanbul in the Black Sea. However, the CIW, within the Black Sea's upper layer flow, does not enter into the strait in the beginning (April, May) and at the end (September) of this period. The CIW between 20 and 50m water depths was observed in the northern entrance of the strait in summer (June, July and August) and it was carried into the strait by the southbound surface current. Its temperature increases southwards along the strait, due to the mixing with the warmer surface and bottom layers. This increment ranges between 2 and 4oC depending on the rate of mixing. The physically altered waters enter the Sea of Marmara with temperature of 11-14oC.In the Sea of Marmara, a residual cold intermediate layer (CIL) is observed in summer, it is just placed on top of the halocline. The average temperature of the upper layer increases from spring to autumn. In some months, however, there is a decrement in the average temperature of the upper layer. The altered CIW waters entering the Sea of Marmara may be responsible for this cooling

    Creep Evaluation of (Orthotic) Cast Materials During Simulated Clubfoot Correction

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    The Ponseti method is a widely accepted and highly successful conservative treatment of pediatric clubfoot that relies on weekly manipulations and cast applications. However, the material behavior of the cast in the Ponseti technique has not been investigated. The current study sought to characterize the ability of two standard casting materials to maintain the Ponseti corrected foot position by evaluating creep response. A dynamic cast testing device (DCTD) was built to simulate a typical pediatric clubfoot. Semi-rigid fiberglass and rigid fiberglass casting materials were applied to the device, and the rotational creep was measured at various constant torques. The movement was measured using a 3D motion capture system. A 2-way ANOVA was performed on the creep displacement data at a significance level of 0.05. Among cast materials, the rotational creep displacement was found to be significantly different (p-values ≪ 0.001). The most creep displacement occurs in the semi-rigid fiberglass (approximately 1.0 degrees), then the rigid fiberglass (approximately 0.4 degrees). There was no effect of torque magnitude on the creep displacement. All materials maintained the corrected position with minimal change in position over time

    Sea level changes along the Turkish coasts of the Black Sea, the Aegean Sea and the Eastern Mediterranean

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    Short, tidal, subtidal, seasonal, secular sea-level variations, sea-level differences and interactions between the basins have been studied, based on the data collected at some permanent and temporary tide gauges located along the Turkish coasts, mostly along the Straits connecting the Marmara Sea to outer seas. Even though the deficiency of sufficient information prevented us to reach the desired results, many pre-existed studies have been improved. Short-period oscillations were clearly identified along the Turkish Strait System and related to their natu-ral periods. The tidal amplitudes are low along the Turkish coasts, except northern Aegean and eastern Mediterranean. The stability of harmonic constants of Samsun and Antalya were examined and most of the long period constituents were found to be unstable. Even the Marmara Sea is not affected from the tidal oscillations of Black and Aegean Seas, some interactions in low frequency band have been detected. Subtidal sea level fluctuations (3-14 day) have relations with the large-scale cyclic atmospheric patterns passing over the Turkish Straits System. Short-term effects of wind on sea level are evident.Seasonal sea-level fluctuations along the Turkish Straits System are in accord with Black Sea's hydrological cycle. The differential range of the monthly mean sea levels between the Black Sea and the Marmara Sea is highly variable; high during spring and early summer and low during fall and winter.On the average, there is a pronounced sea-level difference (55 cm) along the Turkish Straits System. However, the slope is nonlinear, being much steeper in the Strait of Istanbul. This barotrophic pressure difference is one of the most important factors causing the two-layer flow through the system. The topography and hydrodynamics of the straits, the dominant wind systems and their seasonal variations make this flow more complicated. For secular sea level changes, a rise of 3.2 mm/a was computed for Karsiyaka (1935-71) and a steady trend (-0.4 mm /a) has been observed for annual sea levels at Antalya (1935-77). The decreasing trend (-6.9 mm/a) at Samsun is contrary to the secular rising trend of the Black Sea probably because of its rather short monitoring period (1963-77)

    ДУБ М.ЗАЛІЗНЯКА: З ІСТОРІЇ ПАМ’ЯТКООХОРОННОЇ РОБОТИ

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    Стаття присвячена проблемі вивчення, охорони та збереження пам’ятки природи тисячолітнього дуба М.Залізняка. В ній розглядаються етапи дослідження вікового дерева, основні пам’яткоохоронні заходи, проведені для підтримки його життєдіяльностіThis article is about a problem of investigation, saving and protection the monument of nature the millennial oak of M.Zaliznyak. It describes about the stages of research of the tree, the main protection measures in order to obtain it activit

    Late presentation of superior mesenteric artery syndrome following scoliosis surgery: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Obstruction of the third part of the duodenum by the superior mesenteric artery (SMA) can occur following surgical correction of scoliosis. The condition most commonly occurs in significantly underweight patients with severe deformities during the first few days to a week following spinal surgery.</p> <p>Case presentation</p> <p>We present the atypical case of a patient with normal body habitus and a 50° adolescent idiopathic thoracolumbar scoliosis who underwent anterior spinal arthrodesis with instrumentation and developed SMA syndrome due to progressive weight loss several weeks postoperatively. The condition manifested with recurrent vomiting, abdominal distension, marked dehydration, and severe electrolyte disorder. Prolonged nasogastric decompression and nasojejunal feeding resulted in resolution of the symptoms with no recurrence at follow-up. The spinal instrumentation was retained and a solid spinal fusion was achieved with good spinal balance in both the coronal and sagittal planes.</p> <p>Conclusion</p> <p>SMA syndrome can occur much later than previously reported and with potentially life-threatening symptoms following scoliosis correction. Early recognition of the condition and institution of appropriate conservative measures is critical to prevent the development of severe complications including the risk of death.</p

    Manufacturing flow line systems: a review of models and analytical results

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    The most important models and results of the manufacturing flow line literature are described. These include the major classes of models (asynchronous, synchronous, and continuous); the major features (blocking, processing times, failures and repairs); the major properties (conservation of flow, flow rate-idle time, reversibility, and others); and the relationships among different models. Exact and approximate methods for obtaining quantitative measures of performance are also reviewed. The exact methods are appropriate for small systems. The approximate methods, which are the only means available for large systems, are generally based on decomposition, and make use of the exact methods for small systems. Extensions are briefly discussed. Directions for future research are suggested.National Science Foundation (U.S.) (Grant DDM-8914277

    Novel Characterization of Lymphatic Valve Formation during Corneal Inflammation

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    Lymphatic research has progressed rapidly in recent years. Though lymphatic dysfunction has been found in a wide array of disorders from transplant rejection to cancer metastasis, to date, there is still little effective treatment for lymphatic diseases. The cornea offers an optimal site for lymphatic research due to its accessible location, transparent nature, and lymphatic-free but inducible features. However, it still remains unknown whether lymphatic valves exist in newly formed lymphatic vessels in the cornea, and how this relates to an inflammatory response. In this study, we provide the first evidence showing that lymphatic valves were formed in mouse cornea during suture-induced inflammation with the up-regulation of integrin alpha 9. The number of corneal valves increased with the progression of inflammatory lymphangiogenesis. Moreover, we have detected lymphatic valves at various developmental stages, from incomplete to more developed ones. In addition to defining the average diameter of lymphatic vessels equipped with lymphatic valves, we also report that lymphatic valves were more often located near the branching points. Taken together, these novel findings not only provide new insights into corneal lymphatic formation and maturation, but also identify a new model for future investigation on lymphatic valve formation and possibly therapeutic intervention

    A Novel RNAi Lethality Rescue Screen to Identify Regulators of Adipogenesis

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    Adipogenesis, the differentiation of fibroblast-like mesenchymal stem cells into mature adipocytes, is tightly regulated by a complex cascade of transcription factors, including the nuclear receptor Peroxisome proliferator activator receptor γ (PPARγ). RNAi-mediated knock down libraries may present an atractive method for the identification of additional adipogenic factors. However, using in vitro adipogenesis model systems for high-throughput screening with siRNA libraries is limited since (i) differentiation is not homogeneous, but results in mixed cell populations, and (ii) the expression levels (and activity) of adipogenic regulators is highly dynamic during differentiation, indicating that the timing of RNAi-mediated knock down during differentiation may be extremely critical. Here we report a proof-of-principle for a novel RNAi screening method to identify regulators of adipogenesis that is based on lethality rescue rather than differentiation, using microRNA expression driven by a PPARγ responsive RNA polymerase II promoter. We validated this novel method through screening of a dedicated deubiquitinase knock down library, resulting in the identification of UCHL3 as an essential deubiquitinase in adipogenesis. This system therefore enables the identification of novel genes regulating PPARγ-mediated adipogenesis in a high-throughput setting

    Effects of interactions between the constituents of chitosan-edible films on their physical properties

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    The main objective of this work was to evaluate the effect of chitosan and plasticizer concentrations and oil presence on the physical and mechanical properties of edible films. The effect of the film constituents and their in-between interactions were studied through the evaluation of permeability, opacity and mechanical properties. The effects of the studied variables (concentrations of chitosan, plasticizer and oil) were analysed according to a 2 3 factorial design. Pareto charts were used to identify the most significant factors in the studied properties (water vapour, oxygen and carbon dioxide permeability; opacity; tensile strength; elongation at break and Young's modulus). When addressing the influence of the interactions between the films' constituents on the properties above, results show that chitosan and plasticizer concentrations are the most significant factors affecting most of the studied properties, while oil incorporation has shown to be of a great importance in the particular case of transport properties (gas permeability), essentially due to its hydrophobicity. Water vapour permeability values (ranging from 1. 62 × 10 -11 to 4. 24 × 10 -11 g m -1 s -1 Pa -1) were half of those reported for cellophane films. Also the mechanical properties (tensile strength values from 0. 43 to 13. 72 MPa and elongation-at-break values from 58. 62% to 166. 70%) were in the range of those reported for LDPE and HDPE. Based on these results, we recommend the use of 1. 5% (w/w) chitosan concentration to produce films, where the oil and plasticizer proportions will have to be adjusted in a case-by-case basis according to the use intended for the material. This work provides a useful guide to the formulation of chitosan-based film-forming solutions for food packaging applications.The author MA Cerqueira is a recipient of a fellowship from Fundacao para a Ciencia e Tecnologia (FCT, SFRH/BD/23897/2005) and BWS Souza is a recipient of a fellowship from the Coordenacao Aperfeicoamento de Pessoal de Nivel Superior, Brazil (Capes, Brazil)
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