Search results for "naval"
showing 10 items of 153 documents
Chitin synthetase activity in Candida albicans: subcellular distribution in yeast cells and protoplasts
1991
Chitin synthetase activity was detected in a partly zymogenic form in cell-free homogenates obtained from C. albicans yeast cells and protoplasts of the same type of cells. By isopycnic centrifugation on sucrose gradients of the cell-free homogenates two fractions with chitin synthetase activity were obtained: one was associated with the plasma membrane (labelled with [ 3 H]concanavalin A (con A) and buoyant density 1·195 g ml −1 ) in a partly active state, and the second was in the cytoplasm, where the enzyme was in a particulate fully zymogenic form, lacking affinity to con A. The buoyant density of the enzyme found in this location depended on the method of cell breakage. Lysis of partly…
Experimental assessment of the shield-to-salt-fog properties of basalt and glass fiber reinforced composites in cork core sandwich panels applications
2018
Abstract In this paper, the effect of salt-fog exposition on the mechanical behavior of sandwich panels having cork agglomerate core was investigated. In particular, the aim of this research work is to assess the shield function of unidirectional basalt and E-glass reinforced polymer on the aging and failure mechanism of the core when such class of material are destined to operate in hostile environments (e.g., marine environment). To do this, the manufactured sandwich panels were exposed up to 60 days to salt-fog environment, according to ASTM B 117 standard. Unaged and aged specimens were analyzed through three point bending tests after aging time of 10, 25 and 60 days. Digital Image Corr…
Maritime Crossroads : The Knowledge Pursuits of María de Betancourt (Tenerife, 1758-1824) and Joana de Vigo (Menorca, 1779-1855)
2022
This article explores the biographies of two gentlewomen, María de Betancourt (1758–1824) and Joana de Vigo (1779–1855), who lived respectively in Tenerife and Menorca, two crucial nodes in the scientific, commercial and military global networks of the late eighteenth century. Some of their scientific and literary contributions are mapped, paying particular attention to how they became active in contemporaneous learned networks. It is argued that the peculiar, intellectually rich microcosms of the islands shaped these women's lives in ways that enabled them to enter learned circles, either real or imaginary, and from a very modest site to contribute to the global circulation of ideas, goods…
A D-mannose-specific lectin from Gerardia savaglia that inhibits nucleocytoplasmic transport of mRNA.
1987
A new lectin has been isolated from the coral Gerardia savaglia by affinity chromatography, using locust gum as an absorbent, and D-mannose as eluant. Final purification was achieved by Bio-Gel P300 gel filtration. The agglutinin is a protein composed of two polypeptide chains with a Mr of 14800; the two subunits are not linked by disulfide bond(s). The isoelectric point is 4.8, the amino acid composition is rich in the acidic amino acids aspartic acid and glutamic acid. The absorption maximum for the protein was at 276 nm; with a molar absorption coefficient of 1.27 X 10(5) M-1 cm-1. The lectin precipitated erythrocytes from humans (A, B and O), sheep, rabbit and carp with a titer between …
Chitosomes lack concanavalin-A-binding sites
1985
Whether intact or dissociated with digitonin, chitosomes isolated from the fungusMucor rouxii lack the ability to bind concanavalin A. The absence of external or internal concanavalin A-binding sites distinguishes the chitosome membrane no only from plasma membrane but also from membranes of other organelles (endoplasmic reticulum, mitochondrion, vacuole). This differential binding ability was used to partially separate chitosomal chitin synthetase from major membranes in a crude cell-free extract ofM. rouxii.
Parametric Hull Design with Rational Bézier Curves and Estimation of Performances
2021
In this paper, a tool able to support the sailing yacht designer during the early stage of the design process has been developed. Cubic Rational Bézier curves have been selected to describe the main curves defining the hull of a sailing yacht. The adopted approach is based upon the definition of a set of parameters, say the length of waterline, the beam of the waterline, canoe body draft and some dimensionless coefficients according to the traditional way of the yacht designer. Some geometrical constraints imposed on the curves (e.g., continuity, endpoint angles, curvature) have been conceived aimed to avoid unreasonable shapes. These curves can be imported into any commercial Computer Aide…
Sailing dinghy hydrodynamic resistance by experimental and numerical assessments
2020
Abstract Hull forms of high-performance sailing dinghies are very interesting for yacht designers. After a long period in which the attention has been focused on one-design boats, in recent years a few exciting restricted classes such as International Moth, International 14′, 18’ Skiff and Class A catamaran become recognized in several countries and led to interesting advances in high-performance yacht design. “1001VELAcup R3” class is two people racing dinghy designed according to a box rule with limitation on LOA and Bmax and total sail area. The boats must be designed and built by students of European Universities and race yearly in Italy. This paper focuses on two best-ranked boats “LED…
Dynamic evaluation of aggregation and agglutination of red blood cells.
1984
Viscoelastic evaluation of aggregation and agglutination of red blood cells was attempted. A concentric double cylinder viscoelastometer was used for determining the dynamic rigidity modulus and loss modulus of blood sample. The dynamic rigidity modulus of horse blood were measured over a wide range of hematocrit. The relation between the viscoelastic behavior and the erythrocyte sedimentation was examined. The change in the amount of surface charge of enzyme treated red blood cells was qualitatively estimated from the measurements of dynamic viscoelasticity of red blood cells suspension with added poly-L-lysine. The dynamic rigidity modulus of red blood cells agglutinated by adding lectin …
A New Systematic Series of Foil Sections with Parallel Sides
2020
Parallel-sided foil sections are used for centerboards and rudders in sailing dinghy classes and also for struts placed in a fluid flow. The objective of this work is to create a systematic series of parallel-sided sections to be used under different conditions, with an emphasis on the sailing dinghies 470, 420 and Optimist. The loss, and surprisingly the gain, in performance relative to 4-digit NACA sections are also investigated. A 2D Reynolds-averaged Navier&ndash
Phasor-FLIM analysis of Thioflavin T self-quenching in Concanavalin amyloid fibrils
2020
The formation of amyloid structures has traditionally been related to human neurodegenerative pathologies and, in recent years, the interest in these highly stable nanostructures was extended to biomaterial sciences. A common method to monitor amyloid growth is the analysis of Thioflavin T fluorescence. The use of this highly selective dye, diffused worldwide, allows mechanistic studies of supramolecular assemblies also giving back important insight on the structure of these aggregates. Here we present experimental evidence of self-quenching effect of Thioflavin T in presence of amyloid fibrils. A significant reduction of fluorescence lifetime of this dye which is not related to the propert…