Highly Selective Reaction of α-Halo-α,β-unsaturated Esters with Ketones or Aldehydes Promoted by SmI2: An Efficient Alternative Access to Baylis—Hillman Adducts.

Samples of heparinized blood, or bone marrow aspirates, or cell suspensions prepared from biopsied tissues (nodes, spleen, etc. ) are routinely prepared, after Ficoll-Hypaque concentration of the mononuclear leucocytes, for scanning electron microscopy. One drop of the cell suspension is placed in a moist chamber on a poly-l-lysine pretreated plastic coverslip (Mazia et al., J. Cell Biol. 66:198-199, 1975) and fifteen minutes allowed for cell attachment. Fixation, started in 2. 5% glutaraldehyde in culture medium at room temperature for 30 minutes, is continued in the same fixative at 4°C overnight or longer. Ethanol dehydration is immediately followed by drying at the critical point of CO2 or of Freon 13. An efficient alternative method for ethanol dehydrated cells is to dry the cells at low temperature (-75°C) under vacuum (10-2 Torr) for 30 minutes in an Edwards-Pearse freeze-dryer (de Harven et al., SEM/IITRI/1977, 519-524). This is preceded by fast quenching in supercooled ethanol (between -90 and -100°C).

Download Full-text

Cytochemical Localization of Polysaccharides in Diplodia Maydis With Thiosemicarbazide : Evaluation of Three Fixatives For Pa:Tsc:Os Reaction

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100090221 ◽

1976 ◽

Vol 34 ◽

pp. 48-49 ◽

Cited By ~ 1

Author(s):

Judith A. Murphy ◽

Mary R. Thompson ◽

A.J. Pappelis

Keyword(s):

Reaction Center ◽

Osmium Tetroxide ◽

Periodic Acid ◽

Cytochemical Localization ◽

Thin Sections ◽

Selective Reaction ◽

Amorphous Character

In an attempt to identify polysaccharide components in thin sections of D. maydis, procedures were employed such that a PAS localization could be carried out. Three different fixatives were evaluated ie. glutaraldehyde, formaldehyde and paraformaldehyde. These were used in conjunction with periodic acid (PA), thiosemicarbazide(TSC), and osmium tetroxide(Os) to localize polysaccharides in V. maydis using a pre-embedded reaction procedure. Polysaccharide localization is based on the oxidation of vic-glycol groups by PA, and the binding of TSC as a selective reaction center for the formation of osmium black. The reaction product is sufficiently electron opaque, insoluble in lipids, not altered when tissue is embedded, and has a fine amorphous character.

Download Full-text

A Consistent Implementation of Inelastic Material Models into Steady State Rolling

Tire Science and Technology ◽

10.2346/tire.16.440302 ◽

2016 ◽

Vol 44 (3) ◽

pp. 174-190 ◽

Cited By ~ 2

Author(s):

Mario A. Garcia ◽

Michael Kaliske ◽

Jin Wang ◽

Grama Bhashyam

Keyword(s):

Steady State ◽

Numerical Simulations ◽

Viscoelastic Material ◽

Rolling Contact ◽

Arbitrary Lagrangian Eulerian ◽

Ale Formulation ◽

Inelastic Material ◽

Material Formulation ◽

Steady State Rolling ◽

Efficient Alternative

ABSTRACT Rolling contact is an important aspect in tire design, and reliable numerical simulations are required in order to improve the tire layout, performance, and safety. This includes the consideration of as many significant characteristics of the materials as possible. An example is found in the nonlinear and inelastic properties of the rubber compounds. For numerical simulations of tires, steady state rolling is an efficient alternative to standard transient analyses, and this work makes use of an Arbitrary Lagrangian Eulerian (ALE) formulation for the computation of the inertia contribution. Since the reference configuration is neither attached to the material nor fixed in space, handling history variables of inelastic materials becomes a complex task. A standard viscoelastic material approach is implemented. In the inelastic steady state rolling case, one location in the cross-section depends on all material locations on its circumferential ring. A consistent linearization is formulated taking into account the contribution of all finite elements connected in the hoop direction. As an outcome of this approach, the number of nonzero values in the general stiffness matrix increases, producing a more populated matrix that has to be solved. This implementation is done in the commercial finite element code ANSYS. Numerical results confirm the reliability and capabilities of the linearization for the steady state viscoelastic material formulation. A discussion on the results obtained, important remarks, and an outlook on further research conclude this work.

Download Full-text

p-Sulfonic acid calix[n]arene catalyzed synthesis of bioactive heterocycles: A review

Current Organic Chemistry ◽

10.2174/1385272824999201019162655 ◽

2020 ◽

Vol 24 ◽

Author(s):

Bubun Banerjee ◽

Gurpreet Kaur ◽

Navdeep Kaur

Keyword(s):

Supramolecular Chemistry ◽

Sulfonic Acid ◽

Catalytic Efficiency ◽

The Other ◽

Reaction Conditions ◽

Metal Free ◽

Bioactive Scaffolds ◽

Wide Range ◽

Efficient Alternative ◽

Bioactive Heterocycles

: Metal-free organocatalysts are becoming an important tool for the sustainable developments of various bioactive heterocycles. On the other hand, during last two decades, calix[n]arenes have been gaining considerable attention due to their wide range of applicability in the field of supramolecular chemistry. Recently, sulfonic acid functionalized calix[n] arenes are being employed as an efficient alternative catalyst for the synthesis of various bioactive scaffolds. In this review we have summarized the catalytic efficiency of p-sulfonic acid calix[n]arenes for the synthesis of diverse biologically promising scaffolds under various reaction conditions. There is no such review available in the literature showing the catalytic applicability of p-sulfonic acid calix[n]arenes. Therefore, we strongly believe that this review will surely attract those researchers who are interested about this fascinating organocatalyst.

Download Full-text

Mechanistic Study on Facet-Dependent Deposition of Metal Nanoparticles on Decahedral-Shaped Anatase Titania Photocatalyst Particles

Catalysts ◽

10.3390/catal8110542 ◽

2018 ◽

Vol 8 (11) ◽

pp. 542 ◽

Cited By ~ 4

Author(s):

Kenta Kobayashi ◽

Mai Takashima ◽

Mai Takase ◽

Bunsho Ohtani

Keyword(s):

Mechanistic Study ◽

Phase Reaction ◽

Surface Charges ◽

Platinum Nanoparticle ◽

Nanoparticle Deposition ◽

Selective Reaction ◽

Anatase Titania ◽

Deposition Density ◽

Titania Photocatalyst ◽

Source Materials

Facet-selective gold or platinum-nanoparticle deposition on decahedral-shaped anatase titania particles (DAPs) exposing {001} and {101} facets via photodeposition (PD) from metal-complex sources was reexamined using DAPs prepared with gas-phase reaction of titanium (IV) chloride and oxygen by quantitatively evaluating the area deposition density on {001} and {101} and comparing with the results of deposition from colloidal metal particles in the dark (CDD) or under photoirradiation (CDL). The observed facet selectivity, more or less {101} preferable, depended mainly on pH of the reaction suspensions and was almost non-selective at low pH regardless of the deposition method, PD or CDL, and the metal-source materials. Based on the results, the present authors propose that facet selectivity is attributable to surface charges (zeta potential) depending on the kind of facets, {001} and {101}, and pH of the reaction mixture and that this concept can explain the observed facet selectivity and possibly the reported facet selectivity without taking into account facet-selective reaction of photoexcited electrons and positive holes on {101} and {001} facets, respectively.

Download Full-text

A Functional Open-Tray Impression Technique for Implant-Retained Overdenture Prostheses

Journal of Oral Implantology ◽

10.1563/aaid-joi-d-10-00159 ◽

2012 ◽

Vol 38 (5) ◽

pp. 617-619 ◽

Cited By ~ 1

Author(s):

Tuncer Burak Ozcelik ◽

Burak Yilmaz

Keyword(s):

Impression Material ◽

Impression Technique ◽

Technical Report ◽

Efficient Alternative

Several implant impression techniques with different materials have been described in the literature. Generally, border molding, functional, and final impressions have been made with 3 different materials, which makes the procedure technique-sensitive and time-consuming. A combination of open-tray and functional impression techniques is described in this technical report. Border molding and functional impression procedures are made at the same time using a vinyl polysiloxane impression material, which makes this technique a simple and time-efficient alternative for clinicians.

Download Full-text

The price of immersion: language learners as a cheap workforce in Malta’s voluntourism industry

Multilingua ◽

10.1515/multi-2020-0178 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Larissa Semiramis Schedel

Keyword(s):

Second Language Acquisition ◽

Language Learning ◽

English Learners ◽

English Language ◽

Voluntary Work ◽

Island State ◽

Classroom Language ◽

Mediterranean Island ◽

Efficient Alternative ◽

Travel Industry

Abstract This contribution treats “language immersion” as a linguistic ideology and explores narratives, practices, and subjectivities pertinent to that notion in the context of language-motivated voluntourism. Voluntourism programs offer short-term sojourns abroad, which combine voluntary work with holidays while promising “immersion” as an efficient alternative to classroom language learning. In the Mediterranean island state of Malta, whose population is mostly bilingual in English and Maltese, voluntourism has become an attractive product for the booming English language travel industry. Since there is a lack of critical sociolinguistic and second language acquisition research on the language learning trajectories of voluntourists, this piece examines the promise of immersion through the example of a hostel that figures as a workplace. Drawing on ethnographic data, it investigates how learning English through immersion while working abroad is imagined and promoted, whether or not it occurs, and what gains (linguistic or otherwise) it generates and for whom. The article argues that the voluntourism industry appropriates the discourse of immersion to responsibilize English learners for their linguistic self-skilling, thereby constituting them as neoliberal subjects that can easily be exploited as a cheap workforce.

Download Full-text