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To determine the kinetics of phase transformations, a calculated CCT-diagram for a titanium alloy of the Ti-Al-Zr-Si-Mo-Nb-Sn alloying system is obtained. The study of the structure and mechanical properties of the heat- resistant alloy of the Ti-Al-Zr-Si-Mo-Nb-Sn alloying system, which are obtained at different temperatures after ther modeformation treatment, is carried out. As established, the deformation treatment carried out in the upper part of the area of the existence of (α+β)-phases made it possible to increase the strength of the material at the room and operating temperatures and, that is especially important, to increase significantly the plasticity of the material, allowing only a slight decrease on average in its yield strength during short-term tests. As also found, a greater degree of deformation destroys hard silicide layers, distributes silicides more uniformly, increases both the strength and plasticity of the alloy, and slightly reduces the heat-resistant properties at 600°C. [ABSTRACT FROM AUTHOR]

A complex of research work was performed on the base of eBm technology to produce high-strength complex titanium alloys of Ti-Al-Zr-Si-Mo-Nb-Sn system with silicon content, higher than the thermodynamically stable value in the solid solution. alloys of this system are promising for creation of a new class of materials with a high level of heat-resistant characteristics. It is shown that EBM allows producing ingots of high-temperature titanium alloys of Ti-Al-Zr-Si-Mo-Nb-Sn system, which are characterized by sufficient chemical homogeneity and absence of casting defects. It is found that tin presence lowers silicon solubility in the test alloys and intensifies silicide release. Here the structure is also refined. It is found that additional alloying elements influence silicon solubility in titanium, forming complex silicides of (Zr, Ti)5si (ti, Zr)3si type in the test alloys. It is shown that the microstructure of the test cast alloys consists of platelike a-phase packets within primary ß-grains, having different crystallographic orientation. [ABSTRACT FROM AUTHOR]

The fucoidan SdeF was isolated from brown alga Saccharina dentigera. The structure of the obtained polysaccharide was studied by chemical methods, NMR spectroscopy of the fully and partially desulfated derivatives, and mass spectrometry of the fucoidan fragments, labeled with 18O. The SdeF was shown to be sulfated (40%) 1,3-linked α-L-fucan, with branches at C2. The sulfate groups were found at positions C2 and C4. Derivatives SdeFDS and SdeFPL were obtained by solvolytic desulfation and autohydrolysis of SdeF , respectively. According to 13C NMR data, SdeFDS is 1,3-linked α-L-fucan, while SdeFPL is 4-sulfated 1,3-linked α-L-fucan. Native fucoidan SdeF was shown to be a non-toxic anticancer substance in the model of human malignant melanoma RPMI-7951, colorectal adenocarcinoma HCT-116, and small intestine adenocarcinoma HuTu 80 cells. The partial desulfation of SdeF at C2 and/or the reduction of its Mw, from 229 to 28 kDa, decreased the anticancer activity; complete removal of the sulfated groups and/or Mw reduction to 4.7 kDa further reduced the effect of this polysaccharide. [ABSTRACT FROM AUTHOR]

The laminaran DdL and fucoidan DdF were obtained from the brown alga Dictyota dichotoma . DdF was a sulfated (28.9%) and acetylated heteropolysaccharide containing fucose, galactose, mannose and glucose (57.9, 20.4, 12.4 and 9.2 mol%, respectively). DdL was a 1,3;1,6-β- d -glucan with the main chain built from 1,3-linked glucose residues and single glucose residue in branches at C6 (one branch on three glucose residues of the main chain). Sulfated (43.7%) laminaran DdLs was obtained from DdL by sulfation. It was determined that sulfates occur at C2, C4 and C6 of glucose residues. The anticancer effect of DdF, DdL, and DdLs (200 μg/mL) was studied in vitro on colon cancer cells HCT-116, HT-29, and DLD-1. The effect of polysaccharides (40 μg/mL) on colony formation of DLD-1 cancer cells after irradiation (4 Gy) was investigated first. All polysaccharides showed a synergistic effect with X-ray irradiation against cancer cells, decreasing the amount and size of cancer cells colonies. [ABSTRACT FROM AUTHOR]

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A fucoidan ScF from brown alga Saccharina cichorioides was extracted, purified and partially depolymerized by autohydrolysis at 37 °C for 24, 48 and 72 h. Supernatant (SN) and pellet (PL) fractions were obtained by ethanol precipitation of each sample. Unlike spectral data of ScF, NMR of PL derivatives clearly suggested the structure: 1,3-linked α- l -Fuc p -4- O SO 3 − repeating unit. Molecular weights (MWs) of PL fractions were 30, 26 and 18 kDa for 24, 48 and 72 h of autohydrolyis, respectively. MALDI-TOFMS, size-exclusion HPLC and carbohydrate polyacrylamide-gel electrophoresis (C-PAGE) indicated a similarity of SN mixtures. They consisted mainly of a polysaccharide part (MW 6 kDa, C-PAGE data) with a structure similar to PL components (NMR data) and monosaccharides α- l -Fuc p -4- O SO 3 − , α- l -Fuc p -2,4-di- O SO 3 − . PL fractions exhibited almost identical antiproliferative activity in vitro as native fucoidan, while an SN sample for 72 h of autohydrolysis was slightly more active against colony formation of colorectal carcinoma cells HT-29. [ABSTRACT FROM AUTHOR]

Fixing hardware made of carbon, high-carbon, and alloyed wires is one of the widespread critical parts in mechanical engineering. The characteristics of fixtures and fasteners and their performance figures are assessed at all stages of steel-making operation, from the choice of burden stock for metal smelting to the method of preparing calibrated rolled metal parts and upsetting end products. Material used for producing long high-duty bolts must be both sufficiently strong and ductile, have homogeneous mechanical properties and chemistry, and no inner or surface defects. When manufacturing fasteners, hot-rolled metal is often plastically deformed by drafting before cold upsetting, and all unacceptable defects are removed by the expensive procedure of latheturning. Moreover, this technology of metal processing entails losses of up to 5.5 % in chips. This paper suggests a resource-efficient and environmentally friendlier fabrication method for calibrated rolled metal items made of steel 38XA, 9.65 mm diameter, for cold die-forging of highduty bolts used in automotive engines, which helps spare expensive lathemachining processes. Moreover, rolled steel produced using this technology is characterized by high resistance to plastic deformation when cold, which leads to increase n wear-resistance of tools in cold dieforging of bolts. [ABSTRACT FROM AUTHOR]

Abstract: Fucoidan was isolated and purified from the brown algae Fucus evanescens and subjected to autohydrolysis to obtain low-molecular-weight fragments. MALDI-TOFMS analysis has shown that monosulfated fucose and more heavily sulfated (up to 5) fucooligosaccharides with polymerization degree (DP) 2, 4 and 6, including galactose-containing sulfated oligosaccharides were the products of autohydrolysis. The structural features of these fragments were elucidated by negative-ion potential lift tandem MALDI-TOF mass-spectrometry using arabinoosazone as a matrix, which allowed reducing the in-source fragmentation. Native fucoidan has been shown to exert anticancer activities in both human malignant melanoma cell lines SK-MEL-28 and SK-MEL-5. Low-molecular-weight fragments exhibited almost no action to cell proliferation in both cell lines and colony formation on SK-MEL-5 cells, but its inhibition activity to the colony formation of SK-MEL-28 cell lines was as high as was demonstrated by native fucoidan (70%). Probably, the inhibiting activity for SK-MEL-28 depended on the presence of sulfates and (1→4)-linked α-l-Fucp residues in the main chain of fucoidan/oligosaccharides. [Copyright &y& Elsevier]

Abstract: Water-soluble polysaccharide fractions were extracted from the brown alga Laminaria cichorioides. Samples were collected monthly from May to October in Troitsa Bay (Japan Sea, Russia). Analysis showed that the content and monosaccharide composition of the fractions changed with the collection season. Fucoidan was isolated and purified from the most fucose-rich fraction, collected in July, and subjected to autohydrolysis to obtain fucooligosaccharides, suitable for mass-spectrometric analysis. Both ESIMS and MALDI-TOFMS analyses show that multisulfated (up to 3) fucooligosaccharides with polymerization degree n from 2 to 5, including mono- and disulfated-fucose residues, were the major products of autohydrolysis. The structural features of the fucooligosaccharides and their alditol derivatives were elucidated by tandem MALDI-TOFMS and ESIMS. The results obtained allowed us to conclude that fragments of the fucoidan, collected in July, were predominantly linked with a (1→3)-type of linkage and that sulfate groups occupied mostly C-2 or C-2/C-4 of the α-l-fucose residues. [ABSTRACT FROM AUTHOR]

Abstract: A fucoidan, a heterogeneous sulfated polysaccharide from the brown alga Fucus evanescens, was depolymerized under solvolytic conditions, and its ethanol-extracted low-molecular-weight fraction was analyzed by MALDI-TOFMS and ESIMS/MS. It was found that the mixture contained unsulfated oligosaccharides including some monosulfated components, which were shown to consist of mainly (1→3)-linked 2-O-sulfonated fucose residues (from 1 to 4). Minor components of the mixture were shown to contain 2-O- and 4-O-sulfonated xylose and galactose residues. Among them, mixed monosulfonated fucooligosaccharides were detected and characterized: Xyl-(1→4)-Fuc, Gal-(1→4)-Fuc, Gal-(1→4)-Gal-(1→4)-Fuc, Gal-(1→4)-Gal. Fucose, galactose, and xylose residues were shown to be mainly 2-O-sulfonated with traces of 4-O-sulfonation. Glucuronic acid was also found as a part of non-sulfated fucooligosaccharides: Fuc-(1→3)-GlcA, Fuc-(1→4)-Fuc-(1→3)-GlcA, Fuc-(1→3)-Fuc-(1→4)-Fuc-(1→3)-GlcA. [Copyright &y& Elsevier]

Laminaran and three fucoidan fractions were obtained from the brown alga Alaria marginata . Alaria angusta, studied earlier by us, has the same polysaccharide composition. Galactofucan AmF3 from A. marginata has a main chain of → 3)-α- l -Fuc p -(2,4- S O 3 − )-(1 → residues, similar to galactofucan from A. angusta . However, the structure of the branches in fucoidan AmF3 can differ from those in the fucoidan from A. angusta. The following fragments were identified in AmF3: HexA-(1 → 2)-Fuc, HexA-(1 → 2)-Gal, Gal-(1 → 4)-HexA, Fuc-(1 → 2)-Gal-6-SO 3 − , Fuc-4-SO 3 − -(1 → 6)-Gal, Gal-(1 → 2)-Gal-2-SO 3 − , Gal-4-SO 3 − -(1  → 6)-Gal, Gal-4-SO 3 − -(1 → 3)-Fuc-(1 → 3)-Fuc, Fuc-4-SO 3 − -(1 → 6)-Gal-(1 → 4)-Gal, Gal-(1 → 4)-Gal-(1 → 3)-Fuc, Gal-2-SO 3 − -(1 → 4)-Gal-(1 → 4)-Gal, Gal-(1 → 4)-Gal-6-SO 3 − -(1 → 2)-Gal. Chains of galactose residues (DP up to 9) were found in AmF3 fucoidan. The laminarans, galactofucans and their derivatives from both algae exhibited no cytotoxicity in vitro . Polysaccharides from A. angusta were more effective against colony formation of HT-29 cells, while those from A. marginata had a greater effect on T-47D cells. Sulfated and desulfated fucoidans possessed weak antitumor activity using SK-MEL-28 cells. [ABSTRACT FROM AUTHOR]

Abstract: Four fucoidan fractions from brown alga Costaria costata, collected at different life-stages: vegetative, May (5F2 and 5F3) and generative, July (7F1 and 7F2) collections were characterized. It was found that seaweed synthesizes different set of fucoidans – one with high fucose content and substantial percentage of hexoses and uronic acid and lower sulfate content (7F1, 5F2 and 5F3) and other – highly sulfated galactofucan (7F2). Structural features of fractions 7F2 and 5F3 were predominantly determined by mass spectrometric analysis of low-molecular-weight (LMW) oligosaccharide fragments, obtained by autohydrolysis of 7F2 and mild acid hydrolysis of 5F3 fucoidans. It was found that oligosaccharides from 7F2 fractions were mainly built up of sulfated at C-2 and/or at C-2/C-4 (1→3)-linked α-l-fucopyranose residues. d-Galactose residues, sulfated either at C-2 or C-6, were found as parts of mixed di- and trisaccharides at both termini and, probably, internal. Fucose residues in 5F3 fucoidan fragments were sulfated at C-2 and sometimes at C-4. Galactose residues were sulfated at C-4 and less frequently at C-2. Resistant to hydrolysis fraction was probably a core, built up with fucose, mannose and glucuronic acid. Presumably, oligosaccharide fragments were branches at C-4 of GlcA. They were sulfated at C-2 and sometimes at C-4 (1→3)- and/or (1→4)-linked fucooligosaccharides (sometimes terminated with (1→3)-linked galactose) and sulfated at C-4 or C-2 (1→4)- or, probably, (1→6)-linked galactooligosaccharides, probably, with own branches, formed by (1→2)-linked galactose residues. Unsulfated xylose residues were probably terminal in chains built up of fucose. It was confirmed, that monosaccharide content and structure of fucoidans of vegetative algae changed following its life stage. Generative alga in general produced highly sulfated galactofucan having lower MW along with less sulfated mannoglucuronofucan with higher MW, which was extensively synthesized by vegetative algae. [Copyright &y& Elsevier]

Fucoidans are biologically active sulfated polysaccharides of brown algae. They have a great structural diversity and a wide spectrum of biological activity. This review is intended to outline what is currently known about the structures of fucoidans and their radioprotective effect. We classified fucoidans according to their composition and structure, examined the structure of fucoidans of individual representatives of algae, summarized the available data on changes in the yields and compositions of fucoidans during algae development, and focused on information about underexplored radioprotective effect of these polysaccharides. Based on the presented in the review data, it is possible to select algae, which are the sources of fucoidans of desired structures and to determine the best time to harvest them. The use of high purified polysaccharides with established structures increase the value of studies of their biological effects and the determination of the dependence "structure - biological effect". • Classification of fucoidans based on their structures was proposed. • Data on yields and composition of fucoidans during algae development were generalized. • Information on radioprotective effect of fucoidans was summarized. [ABSTRACT FROM AUTHOR]

• Polysaccharide composition of brown alga Tauya basicrassa was studied. • Alginate and laminarans had typical structures for those substances. • Fucoidans were low- and medium-sulfated heterogeneous polysaccharides. • The main chain of fucogalactan 1TbF1 consisted of 1,6-linked β-D-Gal p. • Laminaran 2TbL and its sulphated derivative had radiosensiting activity. Polysaccharide fractions of alginate, laminarans and fucoidans were obtained from the brown alga Tauya basicrassa. Yields of alginate and laminarans were large (19.7 % and 5.62 %, respectively), whereas the content of fucoidans (0.52 %) was not significant. Alginate and laminarans had typical structures for those substances. Fucoidans were low- and medium-sulfated heterogeneous polysaccharides. The fucoidan fraction 1TbF1 was sulfated fucogalactan containing a backbone from 1,6-linked residues of β- d -galactopyranose with branches at C3 and C4, terminal fucose and galactose residues and fragments from 1,3-; 1,4-; and 1,2-fucose residues. Sulfate groups were found at positions 2 and 4 of fucose, and positions 2, 3 and 4 of galactose residues. Laminaran 2TbL was subjected to a sulfation to obtain the derivative 2TbLS with partial sulfation (46 %) at C2, C4 and C6. It was shown that 2TbL and 2TbLS inhibited colony formation of sensitize-tested colon cancer cells HT-29 and HCT-116 to X-ray radiation. [ABSTRACT FROM AUTHOR]

In the present study, three sulfated polysaccharides, two fractions of fucosylated chondroitin sulfates, and one sulfated fucan were isolated from the body wall of the Vietnamese sea cucumber Stichopus variegatus . The structure of the sulfated fucan fraction SvF3 from S. variegatus was investigated for the first time. According to NMR spectroscopy data, the sulfated fucan SvF3 contained 1,2- and 1,3-linked α- l -fucopyranose residues. Sulfate groups were found at the 2 and/or 4 positions. The structural analysis of fucoidan was assisted by tandem mass spectrometry; the recently-developed technique of autohydrolysis in heavy‑oxygen water for the obtaining of selectively labeled fucoidan fragments was applied. The labeling (+2 Da mass shift at the reducing end) allowed us to assign MS/MS data unambiguously, and thus to confirm the NMR data and revealed minor sulfation at position 3. It was shown that the sulfated fucan SvF3 was not cytotoxic to human breast cancer T-47D and MDA-MB-231 cell lines, and it inhibited colony formation of those cells in vitro . SvF3 also possessed slight activity against migration of MDA-MB-231 cells in vitro . [ABSTRACT FROM AUTHOR]

Laminaran and three fractions of fucoidan were isolated from brown alga Alaria angusta . The laminaran AaL was characterized as a typical 1,3;1,6-β-D-glucan (ratio of bonds 1,3:1,6 = 10:1). Fucoidans AaF1 and AaF2 are sulfated heteropolysaccharides, containing fucose, galactose, mannose and xylose. The fraction AaF3 is sulfated and acetylated galactofucan with the main chain represented by a repeating unit →3)-α-L-Fuc p -(2,4-SO 3 − )-(1→. According the data of methylation analysis, AaF3 contains mainly 1,3-linked fucose, less 1,4-linked and 1,4,6-linked galactose residues. The autohydrolysis (37 °C) of fucoidan AaF3 allowed to obtain selectively 2-desulfaled polysaccharide fraction, built up of fucose only, and low molecular weight (LMW) fraction. The negative-ion tandem mass spectrometry of LMW fraction, further hydrolyzed by acid hydrolysis identified the following fragments: Gal-2-SO 3 − -(1 → 4)-Gal, Gal-4-SO 3 − -(1 → 4)-Gal, Gal-(1 → 2)-Gal-4-SO 3 − , Fuc-2-SO 3 − -(1 → 4)-Gal, Gal-2-SO 3 − -(1 → 3)-Fuc-(1 → 3)-Fuc, Fuc-2-SO 3 − -(1 → 3)-Fuc-(1 → 4)-Gal. The laminaran AaL and the fucoidan AaF3 exhibited no cytotoxicity in vitro for HT 29, T-47D, and SK-MEL-28 cell lines. The AaF3 fraction suppressed colony formation of HT 29 and T-47D cells, AaL —only HT 29 cells. [ABSTRACT FROM AUTHOR]