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Assignment of one of two possible directions to every edge of an undirected graph G = (V , E) is called an orientation of G. The resulting directed graph is denoted by G ⃗. A strong orientation is one in which every vertex is reachable from every other vertex via a directed path in G ⃗. The diameter of G ⃗ , i.e., the maximum distance from any vertex to any other vertex, depends on the particular orientation. The minimum diameter among all possible orientations of G is called the oriented diameter diam ⃗ (G) of G. Let n , k be two integers such that 1 ≤ k < n. In the realm of interconnection networks of processing elements, an (n , k) -star graph S n , k offers a topology that permits to circumvent the lack of scalability of n -star graphs S n. The oriented diameter quantifies an upper limit on the delay in communication over interconnection networks. In this paper, we present a strong orientation scheme for S n , k that combines approaches suggested by Cheng and Lipman (2002) for S n , k with the one proposed by Fujita (2013) for S n , reaping benefits from both worlds. Next, we propose a distributed routing algorithm for S n , k ⃗ inspired by an algorithm proposed in Kumar et al. (2021) for S n ⃗. With the aid of both the orientation scheme and the routing algorithm, we show that diam ⃗ (S n , k) ≤ ⌊ n + k 2 ⌋ + 2 k + 6 − δ (n , k) where δ (n , k) is a non-negative function. The function δ (n , k) takes on values 2 k − n , 0 , and n − 3 k 2 respectively for three disjoint intervals k > n 2 , n 3 < k ≤ n 2 and k ≤ n 3 . For every value of n , k , our upper bound performs better than all known bounds in literature. [ABSTRACT FROM AUTHOR]

An orientation of an undirected graph G is an assignment of exactly one direction to each edge of G. Converting two-way traffic networks to one-way traffic networks and bidirectional communication networks to unidirectional communication networks are practical instances of graph orientations. In these contexts minimising the diameter of the resulting oriented graph is of prime interest. The n -star network topology was proposed as an alternative to the hypercube network topology for multiprocessor systems by Akers and Krishnamurthy (1989). The n -star graph S n consists of n ! vertices, each labelled with a distinct permutation of [ n ]. Two vertices are adjacent if their labels differ exactly in the first and one other position. S n is an (n − 1) -regular, vertex-transitive graph with diameter ⌊ 3 (n − 1) / 2 ⌋. Orientations of S n , called unidirectional star graphs and distributed routing protocols over them were studied by Day and Tripathi (1993) and Fujita (2013). Fujita showed that the (directed) diameter of this unidirectional star graph S n ⃗ is at most ⌈ 5 n / 2 ⌉ + 2. In this paper, we propose a new distributed routing algorithm for the same S n ⃗ analysed by Fujita, which routes a packet from any node s to any node t at an undirected distance d from s using at most min { 4 d + 4 , 2 n + 4 } hops. This shows that the (directed) diameter of S n ⃗ is at most 2 n + 4. We also show that the diameter of S n ⃗ is at least 2 n when n ≥ 7 , thereby showing that our upper bound is tight up to an additive factor. [ABSTRACT FROM AUTHOR]

Abstract The creep behavior of a fully lamellar FeAl/FeAl 2 eutectoid alloy was shown to exhibit a minimum creep rate and the absence of a pronounced steady state regime. To reveal the underlying mechanisms of creep leading to the macroscopic response described above, comprehensive TEM investigation of several crept specimens were performed. In the early stages of creep, the FeAl phase primarily carries creep deformation by dislocation motion, whereas FeAl 2 remains mostly plastically undeformed, except in certain locations near colony boundaries where the lamellar structure is disrupted/absent. Within the colonies, where the lamellae are intact, deformation is accommodated at the FeAl/FeAl 2 interface, resulting in an increase in interface dislocations. This continues to be the case at the minimum creep rate. With further progression in creep, FeAl 2 begins to participate in the process of plastic deformation in a more substantive manner through twinning and slip, while FeAl continues to plastically deform and dynamically recover. Further beyond the minimum, the lamellar structure adjacent to the colony boundaries breaks down, and these areas become the primary contributors to creep and results in a continuous loss in creep resistance. Based on these observations in the fully lamellar material, the creep response of off-eutectoid Fe-58Al and Fe-62Al as well as single-phase FeAl 2 are explained. Highlights • Creep mechanism in a lamellar FeAl/FeAl 2 alloy is examined by electron microscopy. • Initially, FeAl deforms by slip and interface dislocation content increases. • A creep rate minimum then occurs and is associated with slip and twinning in FeAl 2. • Twins nucleate at the FeAl/FeAl 2 interfaces and FeAl 2 twins on the (001) plane. • Increase in creep rate at longer time results from lamellar structure breakdown. [ABSTRACT FROM AUTHOR]

Provides information on an experimental study of the thermal stability of copper silicide passivation layers in copper-based multilevel interconnects. Methodology used to conduct the experiment; Results of the experiment; Discussion on the results.

Inflammatory responses during chronic diseases such as atherosclerosis, cancer etc., are harmful to host organisms. Generally NSAIDs are used to treat against these severe conditions but due to its adverse effects studies are going on with medicinal plants, since they are rich in bioactive compounds. Justicia gendarussa is one such plant which has been used as a remedial measure for treating inflammatory diseases since ancient time. Thus the present study involved in the isolation, characterization and identification of apigenin (flavonoid) from this plant and to elucidate its molecular mechanism against inflammation via TLR-NF-κB signaling pathway using ox-LDL induced hPBMCs in in vitro model. Methanolic extract was used for the isolation process and results showed that the F6 fraction collected from ethyl acetate through column chromatography showed 89% paw edema inhibition at a dose of 10 mg/kg in carrageenan induced rats. Purification of F6 by TLC with toluene: chloroform: acetone (8:5:7) and further characterization by 1 HNMR indicated the presence of bioactive compound, apigenin. In vitro studies revealed that pretreatment of ox-LDL induced hPBMCs with apigenin (25 μM) significantly ( P  < 0.05) reduced the levels of TLR4, MyD88, TRIF, TRAF6, NF-κB, COX-2, PGE2, IL-1β and TNF-α responsible for generating inflammation and elevated the level of anti-inflammatory cytokine, IL-10. These results indicate the therapeutic efficacy of bioflavonoid apigenin which was isolated from Justicia gendarussa against ox-LDL induced inflammation. Therefore apigenin can be treated as a suitable therapeutic agent against inflammatory diseases. [ABSTRACT FROM AUTHOR]

An asymmetric synthesis of a 3′-deoxy-3′- 18 F-fluorothymidine ( 18 F-FLT) precursor has been developed wherein the deoxysugar moiety was synthesized using a novel Ga-mediated allylation of ( R )-2,3-cyclohexylideneglyceraldehyde as the key step. The synthesis deviates significantly from the previous syntheses of the 18 F-FLT precursors wherein the expensive starting material, thymidine was used. [ABSTRACT FROM AUTHOR]

On the Al-rich side of the Fe-Al binary system, the eutectoid decomposition of Fe 5 Al 8 into B2-ordered FeAl and triclinic FeAl 2 in the composition range of 55–65 at.% Al produces an ultrafine lamellar microstructure. The compression creep behavior of such two-phase intermetallic materials was investigated in the temperature range 600–800 °C under constant stress. In addition to the fully lamellar Fe-61Al alloy, Fe-58Al and Fe-62Al that included, pro-eutectoid FeAl and FeAl 2 , respectively, were characterized in terms of their microstructure and creep response. For all microstructures, the strain rate as a function of time and strain exhibits a distinct minimum instead of a steady state creep regime. Microstructure instability, primarily in the vicinity of colony boundaries, is identified as the main reason for the increase in strain rate beyond the minimum. In contrast, lamellar coarsening is shown to be only a secondary factor influencing creep response for the conditions investigated. In comparison to single phase FeAl, the fully lamellar FeAl-FeAl 2 shows enhanced creep resistance while the presence of either pro-eutectoid phase leads to a relative deterioration of the creep resistance. [ABSTRACT FROM AUTHOR]

Stress-controlled uniaxial cyclic tensile tests were conducted on binary Mo-27 at% Re and Mo-0.3 at% Si solid solutions as a function of temperature and compared against the previously reported cyclic response of pure Mo. The Mo-27 at% Re alloy with a recrystallized grain size of ~30 µm was evaluated in the temperature range 25 °C–800 °C at R=0.1 and stress range that was 80% of the ultimate tensile strength (UTS); a peak in fatigue life was observed between 300 °C and 500 °C. The decrease in fatigue life at the higher temperatures of 700 °C and 800 °C is attributed to dynamic strain aging. Transmission electron microscopy of the cyclically-deformed alloy revealed parallel bands of dislocation at room temperature that transitioned to a uniform cell structure at 500 °C and back to orthogonal planar arrays at 800 °C. The as-extruded Mo-0.3 at% Si alloy was evaluated from 25 °C to 1200 °C and showed superior fatigue life and ratcheting strain resistance as compared to pure Mo and the Mo-27 at% Re alloy (within the temperature range where data were available for comparison). The superior resistance is attributed to the high density of dislocations within the material in this mostly unrecrystallized state rather than Si in solid solution. Above 800 °C, the ratcheting strain increases and fatigue life decreases rapidly with increasing temperature and is associated with dynamic recovery. [ABSTRACT FROM AUTHOR]

Ni 1.5 Fe 1.5 O 4 ferrite samples were synthesized by maintaining different pH values (1–12) during chemical reaction at 80 ° C. The as-prepared samples were annealed at 1000 ° C to form a cubic spinel structure. The heat treated samples were used for the study of electrical conductivity and dielectric properties. In this work, we understand the mechanism of unusual metal-like state in ferrite samples, characterized by negative temperature coefficient of conductivity. We have discussed various aspects, e.g., hopping mechanism through superexchange paths (Fe 3+ -O 2− -Fe 3+ and Ni 2+ -O 2− -Ni 2+ ), charge delocalized conduction mechanism affected by the magnetic spins order in t 2g and e g electronic energy levels of B sites cations, grain size variation, relaxation of charge carriers at grains and grain boundaries of the particles, for outlining the mechanism of thermal activated charge localization (semiconductor state) and delocalization (metal-like state) effect in our samples. We have carried out a detailed analysis of conductivity spectra (Jonscher's power law fit, scaling of conductivity), impedance spectra (Cole-Cole plot by incorporating constant phase element), modulus spectra (Bergman proposed KWW function), and dielectric loss and dielectric constant spectra to extract the conductivity and relaxation contributions from grains, grain boundaries and space charge polarization in the samples. [ABSTRACT FROM AUTHOR]

Here we report the synthesis and study of N -succinyl chitosan based hydrogel beads, stabilized with glycopolymeric network (NSC/Glc-gel) for application in anticancer drug delivery of doxorubicin (DOX). The bio-recognition of lectins by NSC/Glc-gel bead was also studied by UV–vis spectrophotometry. The beads were characterized using FT-IR, SEM and Thermogravimetric analysis. The extent of DOX loading was proportional to the degree of succinylation and the swelling kinetics of the beads showed pH dependency. The beads exhibited sustained release of DOX over a period of more than 15 days in an acidic pH, mimicking the microenvironment of tumor cells, and even lesser release at physiological pH. Release exponent ‘ n ’ derived from Korsmeyer–Peppas model implied that NSC88/Glc-gel (88% succinylation of chitosan) beads followed fickian diffusion controlled release mechanism whereas NSC75/Glc-gel (75% succinylation of chitosan) beads follow zero order release profile. The synthesized beads also displayed specificity to lectin Concanavalin A. [ABSTRACT FROM AUTHOR]

Shape memory polymers (SMPs) exhibit exceptional capability to memorise their original shape from a temporary shape by responding to a suitable external stimuli such as heat, pH, current, moisture and so on. Of late, click polymerizations are being emerged as a promising synthetic route to realize novel SMPs. This short-review discusses the recent growth observed in the field of SMPs based on copper catalysed azide-alkyne, thiol-ene and Diels- Alder polymerization methods. The merits, challenges and future directions are addressed. [ABSTRACT FROM AUTHOR]

The magnetic properties of Ni 1.5 Fe 1.5 O 4 ferrite have been investigated using the techniques of dc magnetometry and Mӧssbauer spectroscopy. The material has been prepared by chemical reaction of metal nitrates at different pH values and subsequently, annealed at different temperatures to improve the microstructure. The samples with single-phased cubic spinel structure have been used for magnetic study. The material showed a variety of magnetic features, including superparamagnetic and soft ferromagnetic properties. At room temperature, changes of the ferromagnetic parameters of the material have been found in the range 0–47 emu/g for spontaneous magnetization, 0–0.37 for squareness, and 0–195 Oe for coercivity. Variation of the pH value during chemical reaction and changes of the grain size by thermal treatment played an important role in tuning the coexisting superparamagnetic and ferromagnetic components in the material. Samples prepared at high pH value showed small grain size and superparamagnetic features, whereas the samples prepared at low pH value produced large grain size and better ferromagnetic features. The ferromagnetic properties of the material have been enhanced by lowering the pH value and increasing the annealing temperature. Mössbauer spectra provided insight of the local magnetic order, site occupancy of Ni and Fe ions and oxidation state of Fe ions in the spinel structure of Ni 1.5 Fe 1.5 O 4 ferrite. [ABSTRACT FROM AUTHOR]

N-aralkylpyroglutamides of substituted bispidine were prepared and evaluated for their ability to inhibit collagen induced platelet aggregation, both in vivo and in vitro . Some compounds showed high anti-platelet efficacy ( in vitro ) of which six inhibited both collagen as well as U46619 induced platelet aggregation with concentration dependent anti-platelet efficacy through dual mechanism. In particular, the compound 4 j offered significant protection against collagen epinephrine induced pulmonary thromboembolism as well as ferric chloride induced arterial thrombosis, without affecting bleeding tendency in mice. Therefore, the present study suggests that the compound 4 j displays a remarkable antithrombotic efficacy much better than aspirin and clopidogrel. [ABSTRACT FROM AUTHOR]

A new shape memory polymer was synthesized by Huisgen 1, 3 dipolar polycycloaddition in the absence of solvents. The monomers, namely, 2,2′ (4,4′bispropargylbiphenol) perfluropropane and bisphenol A (bisazidohydroxy propyl) ether, were synthesized and characterized by FTIR, 1 H and 13 C NMR spectroscopies. The polyaddition resulting in polytriazole was performed at 140 °C. The elastic memory carbon composite of the resultant linear polymer possessed transition temperature of 113 °C and exhibited good shape recovery (95%) and shape retention (99%) properties. The polymer is thermally stable up to 275 °C. [ABSTRACT FROM AUTHOR]

Abstract: We report the synthesis, structural and magnetic properties of Ni1.5Fe1.5O4 ferrite nanoparticles. The pH value during coprecipitation from metal nitrates solution has been varied in the range 1–12. The samples after coprecipitation have been annealed at different temperatures to study thermal effect on crystalline phase and grain growth process. A detailed microstructural study has been performed using X-ray diffraction (XRD), Fourier Transform Infra-red Spectroscopy (FTIR), Scanning electron microscopy (SEM) attached with Energy dispersive analysis of X-ray (EDX) spectrometer, and Micro Raman Spectroscopy. XRD pattern showed formation of single phased cubic spinel structure above certain annealing temperature that strongly depends on the pH value during coprecipitation. Analysis of the FTIR and Raman spectra of the samples prepared at different pH values indicated ordering of cations in A and B sites of the cubic spinel structure. EDX data indicated Ni deficiency for the samples prepared at pH 2. Minor hematite (α-Fe2O3) phase has been identified for the samples coprecipitated at pH 4 and 6, in addition to the major cubic spinel phase. The samples of Ni1.5Fe1.5O4 have shown soft ferromagnetic character at room temperature and ferromagnetic parameters varied in a wide range with pH value at which sample was coprecipitated. [Copyright &y& Elsevier]

Abstract: A series of chiral lactam carboxamides of aminomethylpiperidine were synthesized and investigated for the collagen induced in vitro anti-platelet efficacy and collagen plus epinephrine induced in vivo pulmonary thromboembolism. The compound 31a (30 μM/kg) displayed a remarkable antithrombotic efficacy (60% protection) which was sustained for more than 24 h and points to its excellent bioavailability. The compounds 31a (IC50 = 6.6 μM) and 32a (IC50 = 37 μM), as well as their racemic mixture 28i (IC50 = 16 μM) significantly inhibited collagen-induced human platelet aggregation in vitro. Compound 34c displayed dual mechanism of action against both collagen (IC50 = 3.3 μM) and U46619 (IC50 = 2.7 μM) induced platelet aggregation. The pharmacokinetic study of 31a indicated very faster absorption, prolonged and constant systemic exposure and thereby exhibiting better therapeutic response. [Copyright &y& Elsevier]

Abstract: This work describes the synthesis and comparative shape memory properties of cross-linked networks derived from epoxy and cyanate ester monomers containing polyether oligomers as reactive shape memory segments. The hydroxy telechelic oligomers viz. polyethyleneglycol (PEG), polypropyleneglycol (PPG), and polytetramethyleneglycol (PTG) are reacted with epoxy–cyanate ester matrix resulting in shape memory polymers with high transition temperatures. The soft oligomer segments act as flexible linker unit which interconnect oxazolidone, isocyanurate and triazine ring structures in the cross-linked polymer. The resultant cyclomatrix SMPs exhibit high transition temperatures 132, 178 and 161°C respectively for PEG, PPG and PTG integrated SMPs. The Eg /Er ratios are increased in the order PEG98% with recovery time <100s. All the SMPs display good thermal stabilities (both inert and oxidative) above 275°C. [Copyright &y& Elsevier]

Recrystallized, commercially pure Mo, binary Mo–27at.% Re, and as-extruded and variously annealed Mo–0.3at.% Si alloys were tested in uniaxial tension as a function of temperature in vacuum. The Mo–Re solid solution is significantly stronger than Mo and retains the strength to at least 800°C. The alloy exhibits serrated flow in the 500°C–800°C range and this is accompanied by a continuous decrease in ductility with increasing temperature in this temperature range. The recrystallized Mo–0.3at.% Si alloy is softer than pure Mo at room temperature and has high ductility (~60% tensile elongation). In the worked condition, it is significantly stronger (σy >600MPa) but still is ductile at room temperature (~10% tensile elongation). The observation of ductility at room temperature in this Mo–0.3at.% Si solid solution alloy has important implications for multiphase ternary Mo–Si–B alloys of technological interest. [ABSTRACT FROM AUTHOR]

• Soap nut fruit extract has been successfully blended with natural rubber as a natural additive. • Addition of 5 % SNE in to NR increased thermal stability 38.94 %, tensile strength 265 % and elongation 32 %. • Crosslinking the blend using glutaraldehyde enhanced the tensile properties. • Increased glass transition and crystalline melting temperatures exhibited the miscibility. • Blend with 5 % soap nut extract exhibited superior properties. This study aimed at the extraction of soap nut fruit to blend with natural rubber as a natural additive. The effectiveness of blending at various blend ratios has been studied in detail. The effects of soap nut extract on the tensile properties, thermal stability, glass transition and crystalline melting temperatures, solvent transport properties, morphology and antibacterial properties were investigated. FTIR was employed to confirm the presence of functional groups and the interaction between both the blend constituents. Enhancement in the tensile and thermal properties of natural rubber was noticed upon the incorporation of soap nut extract. The increased glass transition and crystalline melting temperatures suggests the miscibility of both blend components. Solvent transport study in benzene showed an increasing trend upon the addition of soap nut extract into natural rubber. SEM microphotographs showed a fine and continuous surface morphology in case of the blend when compared to pure natural rubber. Antibacterial studies revealed that the incorporation of soap nut extract makes natural rubber more stable. The blend with 5 % soap nut extract exhibited superior properties than that of the other blend components. [ABSTRACT FROM AUTHOR]

The aza-Michael reactions with a variety of substrates were conducted in water affording the quantitative yields without any external catalyst, which is contrary to that published in literature. A more rational approach to analyze this problem was by conducting this conspicuous reaction with a variety of substrates in water and the results were analyzed using advanced theoretical calculations. Our investigation on the role of water in the reaction proposed a mechanism wherein water plays dual role both as medium as well as catalyst to facilitate the C–N bond formation using powerful tool in its armory, the "H-bonding". Reactions were conducted in the absence of an external catalyst or co-solvents and, hence, are a greener approach in organic synthesis. The reactions of 15 examples were conducted with a variety of substrates to afford the addition products in the range of 70–95% yield. Theoretical studies on the transition state analysis suggested that it was the assistance of water, through H-bonding, that facilitated the conjugate addition of amine and proton transfer from ammonium ion, which could happen through two equally possible pathways. [Display omitted] • The aza-Michael reactions were conducted in water without catalyst. • The quantitative yields of products were obtained at room temperature. • 15 examples were conducted with a variety of substrates to afford 70–95% yields. • Density functional theory (DFT) calculations were done to probe the role of water. • DFT suggested C–N bond formation was catalyzed by water via H-bonding. [ABSTRACT FROM AUTHOR]

Abstract: A general and efficient route towards the synthesis of three derivatives of structurally and functionally important amino acid, lysine is reported. Chemoselective reduction of aldehydic functionality in C-3-azido conjugated aldehyde 4, under Luche condition, is the key step in the synthetic sequence. The lysine derivative, (2S,3R)-2,6-diazido-3-hydroxy-hex-4-ene-oic acid 9 could be used to prepare switch peptide using Staudinger reaction, while the unprotected (2S,3R)-2,6-diamino-3-hydroxy-hexanoic acid hydrochloride 10 is a proven reaction intermediate towards the synthesis of natural product (−)-Balanol. [Copyright &y& Elsevier]

Phenolic cross linked-epoxy resin based shape memory thermoset was realized through ‘click’ chemistry. Towards this, propargylated novolac and bisphenol A (bis azido hydroxy propyl) ether were synthesized and characterized by FTIR and proton NMR. The functionalized resins were co-cured by click reaction between alkyne and azide group under catalyzed and uncatalysed conditions to form triazole networks. The cure reaction centered around 130°C decreased to 74°C on catalysis by Cu2l2. The triazole coupled phenolic-epoxy thermoset displayed shape memory properties with high foldability, shape fixity of 99% and shape recovery of 90% at a low transition temperature of 73°C. The cross-linked matrix was thermally stable upto 250°C under nitrogen. [ABSTRACT FROM AUTHOR]

Abstract: This review analyses the progress in the field of shape memory epoxy resins (SMEPs). Partial crystallisation and vitrification are the basis of shape memory effect in SMEPs. Several synthetic approaches for SMEPs, their composites and foams have been reviewed. Strategically incorporated thermally reversible segments induce the shape memory effect in epoxy resins. By varying the nature and concentration of shape memory segments, wide range of shape memory properties and transition temperatures (shape memory temperatures) can be achieved. Triple shape memory, self-healability and electroactive capability are some of the additional features that can be created in SMEPs. Among the thermoset resins, shape memory epoxies are the most attractive systems because of the ease of processability, composite forming properties and dimensional stability. Shape memory epoxy polymers that can be processed into elastic memory composites are candidate materials in the processing of many smart engineering systems. In this background, a review consolidating the progress in SMEP has contemporary relevance. The present article takes a stock of the trend in SMEP with a view to assess the direction of future initiatives in this area. It is concluded that there is tremendous scope for research leading to technological evolution in the field of SMEP. [Copyright &y& Elsevier]

Abstract: This study investigates the decay and half-life of online citations cited in four open access journals published between 2000 and 2009. A total of 1158 online citations cited in 1086 research articles published in two science and social science journals spanning a period of 10 years (2000–2009) were extracted. Study found that 24.58% (267 out of 1086) of articles had online citations and these articles contained a substantially very less number of online citations (2.98%) compared to previous study results. 30.56% (26% in Science and 52.73% in Social Science) of online citations were not accessible and remaining 69.44% of online citations were still accessible. The ‘HTTP 404 error message-page not found’ was the overwhelming message encountered and represented 67.79% of all HTTP message. Domains associated with .ac and .net had higher successful access rates while .org and .com/.co had lowest successful access rates. The half-life of online citations was computed to be approximately 11.5 years and 9.07 years in Science and Social science journal articles respectively. [Copyright &y& Elsevier]

Purpose – The main purpose of the present study is to examine the availability and persistence of URL citations in two LIS open access journals. It also intended to calculate the half-life period of URL citations cited in journal articles. Design/methodology/approach – A total of 2,890 URL citations cited in 689 research articles published in LIS journals spanning a period of 14 years (1996-2009) were extracted. In order to check the accessibility of URL citations, W3C link checker was used. After the initial check, inactive URL citations were listed. Domains and HTTP errors associated with inactive URL citations were identified for further analysis. The half-life period was calculated using the formula t(h)=[t ln(0.5)]/[ln W(t)-ln W(0)]. Findings – The research findings indicated that 57.61 percent (397 of 689) of articles have URL citations and percentage of URL citations increased from 5.98 percent in 1996 to 27.79 percent in 2009. It was found that 26.08 percent of all citations were not accessible during the time of testing and the majority of errors were due to HTTP 404 error code (not found). The domains.net and.gov were more stable compared to the domains.com/.co,.org, and.edu. The half-life was computed to be approximately 11.5 years, which compares favorably against earlier research works. Originality/value – This is a comprehensive study on the availability and persistence of URL citations cited in LIS journals articles spanning a period of 14 years. The findings of the study will be helpful to authors, publishers and editorial staff to improve existing URL citation conventions and to promote URL use to ensure that URL citations are accessible in future. [ABSTRACT FROM AUTHOR]

Abstract: Monotonic tensile tests and uniaxial load-controlled tension–tension cyclic tests were performed on commercial purity (99.99%) molybdenum in the recrystallized state in the temperature interval spanning RT (25°C) to 500°C range. Cyclic deformation behavior was characterized by analyzing the ratcheting strain, cyclic hardening response, and fatigue life. The response of unrecrystallized and recrystallized Mo was compared at room temperature; the influence of test variables including mean stress, stress amplitude and R ratio on ratcheting strain in recrystallized Mo at room temperature was also examined. The magnitude and rate of ratcheting strain evolution with cycles appear to depend on both the mean stress and the stress amplitude. Microstructural evolution during cyclic loading was characterized by conducting interrupted tests at room temperature as well as at 400°C. Observations confirm dislocations cell structure formation during cyclic plastic deformation at room temperature and at 400°C, the process occurring more rapidly at the higher temperature; in addition, at the higher temperature some of the cell walls appeared to have transformed into subgrain boundaries, suggesting partial recovery. [Copyright &y& Elsevier]

Abstract: Greenhouse technology provides favorable microclimate for year round cultivation of crops. Floricultural production in the greenhouse is an attractive venture for subtropical India due to its economic and aesthetic value. However, production and quality of flowers suffer due to high summer temperatures. Hence, development of a reliable model to predict the microclimate of greenhouse is necessary to manage the crop production and to optimize the design. Experiments were conducted in two different shape and size of greenhouses to evaluate the microclimate and crop performance. A simple dynamic model was developed to predict air temperature, vapor pressure and canopy temperatures. Submodels of natural ventilation and crop transpiration constituted the sensible and latent heat transfers in the greenhouse. The model was validated for Gerbera crop cultivation during winter and summer seasons. Good agreement was found between the predicted and observed values of temperature with RMSE values of 0.73°C and 0.87°C during winter and summer seasons, respectively. Sensitivity analysis of the model showed that width of side opening and angle of roof vent influenced the model performance considerably. It was concluded that the model can be used as a design tool for prediction of microclimate in the greenhouse for floricultural production. [Copyright &y& Elsevier]

Abstract: Multiphase Mo–Si–B alloys containing a Mo solid solution matrix and brittle Mo3Si and Mo5SiB2 (T2) intermetallic phases are candidates for ultra-high-temperature applications . The elevated temperature uniaxial tensile response at a nominal strain rate of 10−4 s–1 and the tensile creep response at constant load between 1000°C and 1300°C of a (i) single phase solid solution (Mo–3.0Si–1.3B in at.%), (ii) two-phase alloy containing ∼35 vol.% T2 phase (Mo–6Si–8B in at.%) and (iii) three-phase alloy with ∼50 vol.% T2+Mo3Si phases (Mo–8.6Si–8.7B in at.%) were evaluated. The results confirm that Si in solid solution significantly enhances both the yield strength and the creep resistance of these materials. A Larson–Miller plot of the creep data showed improved creep resistance of the two- and three-phase alloys in comparison with Ni-based superalloys. The extent of Si dissolved in the solid solution phase varied in these three alloys and Si appeared to segregate to dislocations and grain boundaries. A stress exponent of ∼5 for the solid solution alloy and ∼7 at 1200°C for the two multiphase alloys suggested dislocation climb to be the controlling mechanism. Grain boundary precipitation of the T2 phase during creep deformation was observed and the precipitation kinetics appear to be affected by the test temperature and applied stress. [Copyright &y& Elsevier]

The Si concentration in the Mo solid solution in ternary Mo-rich Mo–Si–B alloys was measured at room temperature and significantly higher levels than those previously reported were documented. Annealing at 1200 and 800°C failed to produce any decrease in the Si level in solid solution, a consequence of sluggish diffusion kinetics. Measurements confirmed a continuous increase in microhardness of the solid-solution phase with the measured Si level; the results are helpful in rationalizing the high-temperature strength in multiphase alloys. [Copyright &y& Elsevier]

Abstract: Greenhouse technology is a viable option for sustainable crop production in the regions of adverse climatic conditions. High summer temperature is a major setback for successful greenhouse crop production throughout year. The main intent of the paper is to present a comprehensive review on the design and technology for cooling of greenhouse during summer months. Effect of characteristic design parameters on greenhouse microclimate and the applicable cooling technologies have been discussed. A detailed survey of literature revealed that, apart from cooling, studies on greenhouse design, evaluation of new cladding materials for greenhouse covering and natural ventilation with respect to local climate and agronomic condition is necessary to achieve desirable benefits. Analysis of the earlier studies revealed that a naturally ventilated greenhouse with larger ventilation areas (15–30%), provided at the ridge and sides covered with insect-proof nets of 20–40 mesh size with covering material properties of NIR (near infrared radiation) reflection during the day and FIR (far infrared radiation) reflection during night is suitable for greenhouse production throughout year in tropical and subtropical regions. Based on the review, salient areas in need of further research are focused. [Copyright &y& Elsevier]

Abstract: The results of an investigation of microstructural evolution during quasi-static and dynamic deformation of a Fe–10Ni–0.1C steel containing small amounts of V and Mo are reported. In the as-received condition, the steel has a lath martensite microstructure with a mean lath size of ∼150nm, and MC carbides dispersed in it with a mean size of ∼20nm. During dynamic deformation (strain rates of 1×103 s−1 to 4×103 s−1), depending on strain and strain rate, shear localization occurs and is accompanied by an optically visible shear band (∼20μm wide). In the situation where the localization process is in its early stages (lower rates, lower global height strains, or both), the microstructure shows severe local deformation within the band but the initial microstructure is still discernible. With progression in severity of localization, there is clear and reproducible evidence for a central region (∼6–8μm wide) within the shear band composed of ∼300nm size equiaxed grains. Electron microscopy characterization of these grains confirms the presence of both, austenite, with a low dislocation content, and heavily dislocated and/or twinned ferrite. Composition measurements from the individual grains confirm partitionless transformation. When the test conditions are further intensified, a crack “chases” the shear band, with the crack running either partway or all the way through the band and therefore through the sample. Examination of the resulting fracture surfaces provides evidence for the presence of a thin liquid film layer (perhaps 10–20nm or less) at various locations within the shear band that presumably has no shear resistance. Together, these observations provide a microstructural footprint for how deformation progressed during shear localization, a sense for the accompanying thermal profile within the shear band, and evidence for the intensity of localization in this alloy in the condition it was examined. [Copyright &y& Elsevier]

Abstract: Chemical ligation methods for the assembly of functional proteins continue to advance our basic understanding of protein structure and function. In this work, we report on our progress towards the full synthesis of HIV-1 Tat utilizing our newly developed ligation method; side-chain assisted ligation. The HIV-1 Tat was assembled from three fragments wherein the two thioester peptides were synthesized efficiently using the side-chain anchoring strategy following Fmoc-SPPS. The side-chain assisted ligation step was efficient and provided the ligation product in good yield. Following this step, native chemical ligation was used to fully assemble the HIV-1 Tat protein. Although the removal of the auxiliary in small peptides was straightforward, in the case of HIV-1 Tat this step was inefficient thus hampering the completion of the synthesis. [Copyright &y& Elsevier]

Abstract: We report the effect of Cu2+ ion on CaAl2O4 with different molar concentrations of 0.0, 0.4 and 0.8M prepared by simple combustion method. The materials have been characterized by X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR) and scanning electron microscopy (SEM). DC electrical conductivity has also been measured to study the electrical behavior of the materials. The XRD patterns confirm the formation of single-phase CaAl2O4 along with some impurity phases like CaAl4O7, CaAl12O19 and Ca12Al14O33. The FT-IR spectra show the stretching and bending vibrations of the synthesized compounds. DC electrical conductivity of the Ca1−x Cu x Al2O4 is found to vary from 26.46×10−4 to 515.68×10−4 Scm−1 for x =0.0 to x =0.8 at the measuring temperature of 1000°C. SEM images show the morphological features of the compounds. [Copyright &y& Elsevier]

Abstract: Thermosetting polymer blends composed of bisphenol A based benzoxazine (BA-a) and cyanate ester (BACY) were prepared via co-curing of benzoxazine with cyanate ester. DSC results manifested a multiple curing pattern with associated heat of reaction implying a co-reaction between oxazine moiety and cyanate group. The catalysis during the co-curing of blend was ascribed to the cycloaddition reaction between the two groups followed by the ring-opening of benzoxazine and cyclotrimerisation of cyanate ester. The spectral and analytical data supported the possibilities of further polymerization through the insertion of the phenolic ybenzoxazine to cyanate group to form the intermediate iminocarbonate, which further induce curing of cyanate ester to form polycyanurate. A co-reacted network composed of triazine ring as a part of polybenzoxazine matrix is postulated. The co-reaction temperature diminished with increase in cyanate ester content in the blend. A single T g was observed in DMTA of the cured matrix that implied a linked homogeneous matrix containing both triazine and polybenzoxazine. This was substantiated by the TGA, DTA and SEM behavior of the cured polymer. The modulus of the cured blend was higher than those of the component resins of the blend. The co-reaction with cyanate ester enhanced the high temperature stability of polybenzoxazine. [Copyright &y& Elsevier]

Abstract: Hepatic acyl-coenzyme A synthetase (ACS), carnitine palmitoyltransferase-I (CPT-I) and acetyl coenzyme A carboxylase (ACC) are coenzymes associated with the genetic type of obesity in animal models. This paper reports the use of microchip electrophoresis (ME) with a laser-induced fluorescence (LIF) detector based on a reverse transcriptase-polymerase chain reaction (RT-PCR) to detect the amplified DNA fragments of these coenzymes (ACS, CPT-I and ACC) in the mRNA extracted from mice. DNA fragments ranging from 50 to 2652bp were well resolved using this procedure with a running buffer (1× TBE), 0.5% polyvinylpyrrolidone (M r 1,000,000) as the coating gel and 0.7% polyethyleneoxide (M r 8,000,000) as the sieving gel at pH 8.30. The separation of the three RT-PCR products was achieved by ME in a single-run within 17s using programmed field strength gradients (PFSG) (470Vcm−1 for 9s, 205.8Vcm−1 for 2s, 411.6Vcm−1 for 4s, 117.6Vcm−1 for 2s and 470.4Vcm−1 for 8s). The ME-PFSG method was found to be 4 times faster than the method using a constant field and 138 times faster than slab gel electrophoresis. Moreover, the amplified RT-PCR products of the obesity-related coenzymes in C57BL/6J mice were analyzed using only sub-micro liter samples. [Copyright &y& Elsevier]

Abstract: A blend of bisphenol A based benzoxazine (Bz-A) and a bismaleimide (2,2-bis[4(4-maleimidophenoxy) phenyl] propane (BMI), was thermally polymerised in varying proportions and their cure and thermal characteristics were investigated. The differential scanning calorimetric analysis, supplemented by rheology confirmed a lowering of the cure temperature of BMI in the blend implying catalysis of the maleimide polymerisation by benzoxazine. FTIR studies provided evidences for the H-bonding between carbonyl group of BMI and –OH group of polybenzoxazine in the cured matrix. The cured matrix manifested a dual phase behaviour in SEM and DMTA with the minor phase constituted by polybenzoxazine dispersed in an interpenetrating polymer network (IPN) of polybenzoxazine and cured BMI. The IPN possessed improved thermal stability over the constituent polybenzoxazine. A benzoxazine monomer possessing allyl functional groups, 2,2′-bis(8-allyl-3-phenyl-3,4-dihydro-2H-1,3-benzoxazinyl) propane (Bz-allyl) was reactively blended with the same bismaleimide in varying stoichiometric ratios (Bz-allyl/BMI), where the curing involved mainly Alder-ene reaction between allyl- and maleimides groups and ring-opening polymerisation of benzoxazine. The rheological analysis showed the absence of catalytic polymerisation of BMI in this case. The overall processing temperature was lowered in the blend owing to the co-reaction of the two systems to form a single-phase matrix. The cured resins of both Bz-A/BMI and Bz-allyl/BMI blends exhibited better thermal stability than the respective polybenzoxazines. The T g of the IPN was significantly improved over that of polybenzoxazine (Bz-A). However, the co-reaction resulted in a marginal decrease in the T g of the system in comparison to the polybenzoxazine (Bz-allyl). [Copyright &y& Elsevier]

Abstract: The fracture toughness of directional solidified Ti–(45,47)Al–3Nb, Ti–(45,47)Al–3Nb–0.2Si–0.1C, Ti–(45,47)Al–3Nb–0.3Si–0.2C type I alloys and their contribution to crack growth resistance of TiAl–Nb alloys were studied using PST (polysynthetically twinned) crystals produced by directional solidification in FZ (floating zone) furnace. Lamellar orientations in the individual colonies are described using two angles defined with respect to the notch orientation: an in-plane kink angle and a through-thickness twist angle. Therefore, lamellar misorientation across an individual colony boundary is quantified as differences in these angles across the boundary. Crack growth resistance in colony boundary was identified by three-point bend test and crack advance was monitored by interrupted in situ test. From three-point bend test, it was found that the colony boundary could offer significant resistance to crack growth under large twist angle difference. Fracture toughness of type I specimens (in which crack propagates against lamellae boundaries) of the alloys decreased slightly with increasing Si and C contents and increased rapidly with decreasing Al content. The toughness for type I specimens was controlled by α2–α2 spacing in which the delamination-type separation occurred. Compared to 47Al alloys, α2–α2 spacing in 45Al alloys increased by decreasing Al content, therefore, fracture toughness increased rapidly. These results are discussed and the ability to improve toughness by changing Al content, Si and C addition in TiAl–Nb alloys produced by directional solidification is suggested. [Copyright &y& Elsevier]

Abstract: A bis benzoxazine monomer with allyl groups viz: 2,2′-bis (8-allyl-3-phenyl-3,4-dihydro-2H-1,3-benzoxazinyl) propane (Bz-allyl) was synthesized via a solventless method from 2,2′diallyl bisphenol-A, paraformaldehyde and aniline. The chemical structure of Bz-allyl was confirmed by FTIR, 1H NMR and 13C NMR analyses. The monomer manifested a two-stage thermal polymerisation pattern. The first stage was attributed to the polymerisation of the allyl groups and the second to the ring – opening polymerisation of benzoxazine moiety. The polymerisation profile was investigated with DSC, FT-IR, TGA and pyrolysis-GC techniques. A polymerisation mechanism involving the electrophilic addition of the propagating iminium cation on the aniline ring in lieu of the activated sites of bisphenol-A, (which are blocked by allyl and alkyl substituents) was proposed. Additional cross-linking was provided by thermal addition polymerization of allyl groups. As a result of altered cross-linking via the aniline moiety and the additional cross-linking via allyl groups, the cured polymer exhibited a T g of ca. 300°C and high crosslink density. The thermal stability of this polymer was also substantially higher vis-à-vis that of the bisphenol-A based polybenzoxazine. The work focuses on the manipulation of benzoxazine monomer structure to alter the ring-opening polymerisation mechanism and cross-linking to derive polybenzoxazine with improved properties. [Copyright &y& Elsevier]

Abstract: Mo–Si–B alloys are being considered as possible candidates for high-temperature applications beyond the capabilities of Ni-based superalloys. In this paper, the high-temperature (1000–1400°C) compression response over a range of quasi-static strain rates, as well as the monotonic and cyclic crack growth behaviors (as a function of temperature from 20°C to 1400°C) of a two-phase Mo–Si–B alloy containing a Mo solid solution matrix (Mo(Si,B)) with ∼38vol% of the T2 phase (Mo5SiB2) is discussed. Analysis of the compression results confirmed that deformation in the temperature–strain-rate space evaluated is matrix-dominated, yielding an activation energy of ∼415–445kJ/mol. Fracture toughness of the Mo–Si–B alloy varies from ∼8MPa√m at room temperature to ∼25MPa√m at 1400°C, the increase in toughness with temperature being steepest between 1200°C and 1400°C. S–N response at room temperature is shallow whereas at 1200°C, a definitive fatigue response is observed. Fatigue crack growth studies using R =0.1 confirm the Paris slope for the two alloys to be high at room temperature (∼20–30) but decreases with increasing temperature to ∼3 at 1400°C. The crack growth rate (da/dN) for a fixed value of ΔK in the Paris regime in the 900–1400°C range, increases with increasing temperature. [Copyright &y& Elsevier]

A highly efficient method for trimethylsilylation of primary, secondary, tertiary, allylic, and a variety of sugar-derived alcohols using hexamethyldisilazane in the presence of a catalytic amount of ammonium thiocyanate under neutral conditions is reported. [ABSTRACT FROM AUTHOR]

Abstract: The d-glucose derived α,β-unsaturated ester 5 on 1,2-acetonide deprotection, oxidative diol cleavage followed by treatment with N-benzylamine in the presence of NaBH3CN undergoes reductive amination and a concomitant intramolecular conjugate addition reaction leading to the formation of dihydroxypyrrolidine-ester 6a and monohydroxypyrrolidine-γ-lactone 6b . Intermediates 6a and 6b were efficiently converted to (−)-lentiginosine 3a , its 8a-epimer 3b , and pyrrolizidine azasugar 4 in good overall yield. [Copyright &y& Elsevier]

Abstract: The thermal cross-linking polymerization of bisphenol-A based benzoxazine was monitored at different isothermal curing temperatures by rheological analysis. An autocatalytic kinetic model was proposed for the curing of benzoxazine monomer. Gel point (t gel) was determined from tan δ maximum and also from intercept of storage and loss modulus and the corresponding activation energy was estimated. All kinetic parameters including reaction orders and kinetic constants were determined. The autocatalytic effect was very significant. A master equation for the cure rate was generated from the kinetic data that was numerically integrated to predict the cure-profile. The theoretical cure prediction matched reasonably well with the experimental results. The high autocatalytic effect was attributed to the presence of phenolic generated by the ring-opening polymerization; which aids further ring-opening polymerization. [Copyright &y& Elsevier]

Abstract: Fracture toughness and fatigue response in the temperature range 20–1400°C of a two-phase Mo–Si–B alloy is compared to that of a TZM alloy. Fracture toughness of the Mo–Si–B alloy varies from ∼8MPa√m at room temperature to ∼25MPa√m at 1400°C, the increase in toughness with temperature being steepest between 1200 and 1400°C. S–N response at room temperature is shallow whereas at 1200°C, a definitive fatigue response is observed. Fatigue crack growth in vacuum and air in the temperature interval 20–600°C is similar for the Mo–Si–B alloy whereas significant deterioration is noted for TZM when it is tested in air. The difference in response is attributed to differences in the oxide scales formed in the two alloys. The Paris slopes for the two alloys is high at room temperature (∼20–30) and decreases with increasing temperature to ∼3 at 1400°C. For the Mo–Si–B alloy, da/dN for a fixed value of ΔK in the Paris regime in the 900–1400°C range, increases with increasing temperature. Apparent activation energies extracted using an Arrhenius-type relationship illustrate grain-boundary diffusion dominance in the 900–1200°C regime and volume diffusion dominance in the 1200–1400°C regime. [Copyright &y& Elsevier]

The Cr2X (X=Ti, Zr, Hf, Nb or Ta) Laves phases have the hexagonal (2H or 4H) structure at high temperatures and the cubic (3C) structure at room temperature. Their compositional ranges are dictated by their e/a ratios. Experimental observations of two-phase alloys in several of these systems demonstrate that the hexagonal structure is often retained at room temperature. Subsequent annealing at elevated temperature transforms the metastable hexagonal structure to the stable cubic structure. In single-phase Cr2Ti and Cr2Ta, the transformation is extremely sluggish whereas in Cr2Nb, it is rapid. In two-phase alloys, the transformation is almost always sluggish (except in the Cr–Nb system) and is accompanied by compositional changes. Transmission electron microscopic observations are consistent with the transformations being achieved by synchroshear behind glissile synchroshockley dislocations. The synchroshear mechanism is described and the transformation kinetics are discussed in terms of long-range diffusion in two-phase alloys and in terms of the mobility of synchroshockley dislocations in single-phase alloys. [Copyright &y& Elsevier]

This paper presents a study of a fully reusable earth-to-orbit launch vehicle concept with horizontal take-off and landing, employing a turbojet engine for low speed, and a rocket for high-speed acceleration and space operations. This concept uses existing technology to the maximum possible extent, thereby reducing development time, cost and effort. It uses the experience in aerial filling of military aircrafts for propellant filling at an altitude of 13 km at a flight speed of M=0.85. Aerial filling of propellant reduces the take-off weight significantly thereby minimizing the structural weight of the vehicle. The vehicle takes off horizontally and uses turbojet engines till the end of the propellant filling operation. The rocket engines provide thrust for the next phase till the injection of a satellite at LEO. A sensitivity analysis of the mission with respect to rocket engine specific impulse and overall vehicle structural factor is also presented in this paper. A conceptual design of space plane with a payload capability of 10 ton to LEO is carried out. The study shows that the realization of an aerial propellant transfer space plane is possible with limited development of new technology thus reducing the demands on the finances required for achieving the objectives. [Copyright &y& Elsevier]

Reviewing the effects of subjecting solidifying Al and its alloys to various sources of vibration on the resulting casting quality, a simple inexpensive technique for inducing vibration resulting in enhanced density and mechanical properties is devised. It involves minimising turbulence by tilting of mould while pouring as well as inducing vibrations in a solidifying melt by using a simple, handy and inexpensive technique, i.e., hand tapping of the mould with MS rods. The alloys chosen for this study are long freezing range hypoeutectic alloy, Al7Si0.3Mg (LM25/356) and a narrow freezing range eutectic Al&z.sbnd;Si alloy, Al12Si (LM6/413). The simple, inexpensive hand tapping of long freezing range Al7Si0.3Mg alloy solidifying in a permanent mould without and with mould tilting has improved its density, hardness, ultimate tensile strength and % elongation. Properties similar to a degassed Al7Si0.3Mg alloy melt have been exhibited by an undegassed melt subjected to vibration by hand tapping with mould tilting. The latter too aids in reducing the turbulence experienced by the aluminium melt during pouring and mould filling and hence in enhancing all the above properties. However, the effectiveness of both mould tilting and hand tapping is less in degassed Al7Si0.3Mg melt compared to undegassed one. On the other hand, there is only marginal improvement in the said properties of narrow freezing Al12Si eutectic. [Copyright &y& Elsevier]

Nanocrystalline metals and alloys, with average and range of grain sizes typically smaller than 100 nm, have been the subject of considerable research in recent years. Such interest has been spurred by progress in the processing of materials and by advances in computational materials science. It has also been kindled by the recognition that these materials possess some appealing mechanical properties, such as high strength, increased resistance to tribological and environmentally-assisted damage, increasing strength and/or ductility with increasing strain rate, and potential for enhanced superplastic deformation at lower temperatures and faster strain rates. From a scientific standpoint, advances in nanomechanical probes capable of measuring forces and displacements at resolutions of fractions of a picoNewton and nanometer, respectively, and developments in structural characterization have provided unprecedented opportunities to probe the mechanisms underlying mechanical response. In this paper, we present an overview of the mechanical properties of nanocrystalline metals and alloys with the objective of assessing recent advances in the experimental and computational studies of deformation, damage evolution, fracture and fatigue, and highlighting opportunities for further research. [Copyright &y& Elsevier]

A highly flexible, mechanically and chemically stable copolymer, tri(propylene glycol) glycerolate diacrylate cross-linked polystyrene (PS-TRPGGDA), was synthesized by the suspension polymerization and employed as a solid support for peptide synthesis. The beaded polymer support containing secondary hydroxyl functional groups in the cross-linker was used as the growth site for peptide synthesis. The procedure is unique and cost-effective in that it avoids the initial functionalization steps required for most of the styrene-based polymer supports. The resin was characterized by 13 C-CP-MAS NMR spectroscopy and the morphologic features of the resin were investigated using scanning electron microscopy. Swelling studies conducted on the new support revealed that the PS-TRPGGDA resin undergoes more effective swelling and solvation than PS-DVB resin in all solvents used in peptide synthesis. The efficiency of the new support was demonstrated by synthesizing a ‘difficult’ sequence Ala-Arg-(Ala)6 -Lys and comparing it with commercially available Merrifield and Sheppard resins. The synthetic efficiency was further demonstrated by the synthesis of a 24-residue NR 2A peptide substrate of calcium/calmodulin-binding peptide. The high yield and purity of the peptide synthesized on the novel support indicates the positive role of the flexible and hydrophilic cross-linking agent in the solid support. [ABSTRACT FROM AUTHOR]

The Laves phase structure in three Cr-based two-phase alloys, Cr–12Nb, Cr–8Zr and Cr–2Nb–1Zr was characterized using transmission electron microscopy. Whereas in the as-cast condition, Cr2Nb exhibits the twinned C15 structure, Cr2Zr even after hot extrusion and annealing shows a heavily faulted C36 structure (or a higher order polytype such as a 6H structure). The ternary Cr2(Zr,Nb) compound exhibits the C36 structure in the as-cast condition but reverts to the C15 structure after annealing, the structural transformation being accompanied by a composition change. Solid-state precipitates of the Laves phase Cr2(Nb, Zr) in the ternary alloy that result in the matrix after annealing are always associated with dislocations. These dislocations either link to the interdendritic precipitates or link the solid-state precipitates to each other. Since the solubility of Zr is low in the matrix, we propose that pipe diffusion along these dislocations serves as the principal mechanism to redistribute the Zr from the interdendritic precipitates to the solid-state precipitates. [Copyright &y& Elsevier]