scholarly journals Phosphotungstic acid as a novel acidic catalyst for carbohydrate protection and glycosylation

RSC Advances ◽  
2019 ◽  
Vol 9 (58) ◽  
pp. 33853-33862
Author(s):  
Jyun-Siao Chen ◽  
Arumugam Sankar ◽  
Yi-Jyun Lin ◽  
Po-Hsun Huang ◽  
Chih-Hsiang Liao ◽  
...  
Keyword(s):  
Room Temperature ◽  
Phosphotungstic Acid ◽  
Carbohydrate Chemistry ◽  
Acidic Catalyst ◽  
Primary Reactions

This work demonstrates the utilization of PTA as an acidic catalyst in primary reactions of carbohydrate. PTA can be widely used as a catalyst for carbohydrate chemistry. The reactions are executed at 0 °C or room temperature in good yields.

Otoconia perfect/imperfect crystals

1994 ◽  
Vol 52 ◽  
pp. 42-43
Author(s):  
César D. Fermin ◽  
Dale Martin
Keyword(s):  
Image Processing ◽  
Room Temperature ◽  
Phosphotungstic Acid ◽  
Gallus Domesticus ◽  
Crystal Matrix ◽  
Organic Templates ◽  
Image Processing Algorithms ◽  
Processing Algorithms ◽  
Diffraction Patterns

Otoconia of higher vertebrates are interesting biological crystals that display the diffraction patterns of perfect crystals (e.g., calcite for birds and mammal) when intact, but fail to produce a regular crystallographic pattern when fixed. Image processing of the fixed crystal matrix, which resembles the organic templates of teeth and bone, failed to clarify a paradox of biomineralization described by Mann. Recently, we suggested that inner ear otoconia crystals contain growth plates that run in different directions, and that the arrangement of the plates may contribute to the turning angles seen at the hexagonal faces of the crystals.Using image processing algorithms described earlier, and Fourier Transform function (2FFT) of BioScan Optimas®, we evaluated the patterns in the packing of the otoconia fibrils of newly hatched chicks (Gallus domesticus) inner ears. Animals were fixed in situ by perfusion of 1% phosphotungstic acid (PTA) at room temperature through the left ventricle, after intraperitoneal Nembutal (35mg/Kg) deep anesthesia. Negatives were made with a Hitachi H-7100 TEM at 50K-400K magnifications. The negatives were then placed on a light box, where images were filtered and transferred to a 35 mm camera as described.

Highly selective direct azidation of alcohols over a heterogeneous povidone–phosphotungstic solid acid catalyst

2016 ◽  
Vol 40 (12) ◽  
pp. 10240-10245 ◽  
Author(s):  
Sumit Kamble ◽  
Sagar More ◽  
Chandrashekhar Rode
Keyword(s):  
Room Temperature ◽  
Solid Acid ◽  
Phosphotungstic Acid ◽  
Solid Acid Catalyst ◽  
Acid Catalyst ◽  
Product Yields ◽  
Acid Catalyzed

A heterogeneous povidone–phosphotungstic acid catalyzed direct selective azidation of alcohols gave excellent product yields at room temperature.

scholarly journals 3-Bromopyridine-Heterogenized Phosphotungstic Acid for Efficient Trimerization of Biomass-Derived 5-Hydroxymethylfurfural with 2-Methylfuran to C21 Fuel Precursor

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Yufei Xu ◽  
Zhaozhuo Yu ◽  
Hu Li ◽  
Song Yang
Keyword(s):  
Phosphotungstic Acid ◽  
Solvothermal Method ◽  
Reaction Pathway ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
X Ray ◽  
Acidic Catalyst ◽  
Carbon Compounds ◽  
Ft Ir ◽  
Long Chain

The production of long-chain carbon compounds (C9-C21) from biomass derivatives to alternate traditional fossil diesel is sustainable, eco-friendly, and potentially economic for modern industry. In this work, phosphotungstic acid heterogenized by 3-bromopyridine was achieved using a solvothermal method, which was demonstrated to be efficient for trimerization of biomass-derived 5-hydroxymethylfurfural (HMF) with 2-methylfuran (2-MF) to C21 fuel precursor (57.1% yield) under mild reaction conditions. The heterogeneous acidic catalyst could be reused for four consecutive cycles without obvious loss of activity, and different characterization techniques (e.g., XRD (X-ray diffraction), TG (thermogravimetric analysis), SEM (scanning electron microscope), FT-IR (Fourier transform infrared spectroscopy), and BET (Brunauer-Emmet-Teller)) were utilized to investigate the performance of the catalyst. In addition, a plausible reaction pathway was postulated, on the basis of results obtained by NMR (nuclear magnetic resonance) and GC-MS (gas chromatography-mass spectrometer). This strategy provides a facile and efficient approach to prepare a recyclable acidic catalyst for the production of diesel fuel precursor from biomass via controllable polymerization.

Phosphotungstic Acid As An Electron Stain

1968 ◽  
Vol 26 ◽  
pp. 36-37
Author(s):  
Daniel C. Pease
Keyword(s):  
Chondroitin Sulfate ◽  
Room Temperature ◽  
Phosphotungstic Acid ◽  
Freeze Substitution ◽  
Basement Membranes ◽  
Effective Electron ◽  
Tissue Sections ◽  
Brush Borders ◽  
Effects Of Ph ◽  
Acid Environment

Under certain conditions phosphotungstic acid (PTA) can be used as an effective electron stain for demonstrating polysaccharide moieties in tissue sections. There it selectively combines with the glycoproteins of basement membranes, the mucoid layers associated with brush borders, the mucus of goblet cells, the chondroitin sulfate of cartilage matrix, glyco-gen, and “glycocalyces” in general. The initial published investigation indicated that an acid environment was essential for this specificity, but the effect of pH was not systematically explored.Rib cartilage of newborn rats was chosen for a detailed study of the effects of pH on PTA staining, particularly to provide ancillary information on the formation, secretion and deposition of chondroitin sulfate. Cartilage was prepared without chemical fixation by “freeze-substitution” with 70% glycol, or by “inert dehydration” with glycol at room temperature. Dehydrated material was embedded in prepolymerized hydroxy-propyl methacrylate without an intermediate solvent.

A rapid phosphotungstic acid staining method on ultra-thin sections

1994 ◽  
Vol 52 ◽  
pp. 318-319
Author(s):  
K. Chien ◽  
R. L. Van de Velde ◽  
R.C. Heusser ◽  
H. Shiroishi ◽  
A.H. Cohen
Keyword(s):  
Room Temperature ◽  
Phosphotungstic Acid ◽  
Staining Method ◽  
Tap Water ◽  
Petri Dish ◽  
Hereditary Disease ◽  
Microwave Oven ◽  
Staining Procedure ◽  
Thin Sections ◽  
Nail Patella Syndrome

The Nail-Patella Syndrome (NPS) is an autosomal dominant hereditary disease in which about 60% of the patients have glomerular abnormalities. Phosphotungstic acid (PTA) has been used successfully to demonstrate the specific collagen fibrils of NPS within the glomerular basement membrane and/or mesangial matrix in ultra-thin sections. However, in our laboratory we had difficulty staining Eponate 12 sections with PTA. A modified staining procedure which makes use of the microwave has been developed as follows:1. Glutaraldehyde/osmium fixed kidney specimens were embedded in Eponate 12 and ultra-thin sections collected on Gilder 400 mesh copper grids. Grids were stained using a RTV 700 silicone rubber staining pad. This pad contains shallow, round wells (5mm in diameter and 2mm deep) with slots in the center bottom of each well. By bending the pad, the rim of a grid can be inserted into the slot. On release, the grids adhere securely to the wall of the slot.2. 10% aqueous phosphotungstic acid was dropped into the staining wells around each grid. The staining pad was then placed in a moisture chamber consisting of a pre-heated Petri dish containing wetted filter paper and placed in Pelco 3400 laboratory microwave oven for 110 seconds at 80% power. A Tripour beaker containing 200ml room temperature tap water was placed in the microwave oven as a heat sink.

Emerging Role of Room Temperature Ionic Liquids (RTILs) in Carbohydrate Chemistry

2013 ◽  
pp. 345-408 ◽  
Author(s):  
Virendra Prasad ◽  
Divya Kushwaha ◽  
Kunj B. Mishra ◽  
Lallan Mishra ◽  
Vinod K. Tiwari
Keyword(s):  
Ionic Liquids ◽  
Room Temperature ◽  
Room Temperature Ionic Liquids ◽  
Carbohydrate Chemistry

ChemInform Abstract: Emerging Role of Room Temperature Ionic Liquids (RTILs) in Carbohydrate Chemistry

ChemInform ◽  
2014 ◽  
Vol 45 (16) ◽  
pp. no-no
Author(s):  
Virendra Prasad ◽  
Divya Kushwaha ◽  
Kunj B. Mishra ◽  
Lallan Mishra ◽  
Vinod K. Tiwari
Keyword(s):  
Ionic Liquids ◽  
Room Temperature ◽  
Room Temperature Ionic Liquids ◽  
Carbohydrate Chemistry
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