Of C-sucrose

Fig. 40.—Inactivation of Binding of [ C]Sucrose to Taste Papillae by Heating in Boiling...

Phloem Loading. How does sucrose which is produced in the mesophyll cells of source leaves enter the translocation stream and how does this sucrose exit from the translocation stream in the sink regions More importantly, can this tell us anything about agrichemical transport Figure 1A shows an autoradiograph of a source leaf following the accumulation of C-sucrose ( C-label is in white). The label is accumulated markedly into the vein network com-... 

Groothuis DR, Ward S, Itskovich AC, Dobrescu C, Allen CV, Dills C, Levy RM. Comparison of C-sucrose delivery to the brain by intravenous, intraventricular, and convection-enhanced intracerebral infLision. JNeurosurg 1999 90 321-31. 

Among the most important C-disaccharide syntheses reported in 1989 is the preparation of C-sucrose. This analog of table sugar is interesting in that unlike natural sucrose, it cannot be metabolized to lower sugars. An actual synthesis of C-sucrose was reported by Nicotra, et ai.,22>23 and is illustrated in Scheme 8.7.5. As shown, the C-glucoside, prepared as discussed in Chapter 2, was converted to a metallated alcohol in 97% yield. Subsequent oxidation of the metal with iodine followed by oxidation of the alcohol to a ketone and... 

As shown in Scheme 8.11.3, C-sucrose was prepared from the illustrated olefin. Osmylation of the olefin followed by tosylation of the primary alcohol and treatment with base gave the epoxide. The acetonide was then hydrolyzed and the benzyl groups were removed. Spontaneous cyclization of the furanose ring was effected on removal of the acetonide. In all, an efficient synthesis of C-sucrose was accomplished in five steps from the starting olefin. 

Fig. 7. Rate of LDL uptake along the length of the rat small intestine. Hie tissue clearance of rat LDL (LDL uptake) was determined in vivo using a constant infusion technique and [ CJsucrose-labeled LDL. The data are expressed as the pi of plasma cleared of [ C]sucrose-LDL/h/g wet weight. The columns and bars represent the means 1 S.E.M.

Fig. 8. Rate of LDL-cholesterol uptake in the mucosa along the villus-crypt axis in the rat intestine. The rates of LDL-cholesterol uptake were determined by measuring the tissue clearance of [ C]sucrose-labeled LDL in vivo and then isolating different cell fractions from the mucosa. These clearance values were multiplied by the LDL-cholesterol concentration in plasma and expressed as the nmoles of LDL-cholesterol taken up per h/mg of cell protein (panels A and B) or as the percentage of total mucosal uptake found in each cell fraction (panels C and D). The columns and bars represent means +1 S.E.M.

The Provesteen process, developed by Phillips Petroleum Company, employs a proprietary 25,000-L continuous fermentor for producing Hansenu/a jejunii the sporulating form of C. utilis from glucose or sucrose at high cell concentrations up to 150 g/L. The fermentor is designed to provide optimum oxygen and heat transfer (69,70). 

ICUMSA (1) has adopted tables showing the relationship between the concentration of aqueous solutions of pure sucrose, glucose, fmctose, and invert sugar and refractive index at 20.0°C and 589 nm. 

Cane sugar is generally available ia one of two forms crystalline solid or aqueous solution, and occasionally ia an amorphous or microcrystalline glassy form. Microcrystalline is here defined as crystals too small to show stmcture on x-ray diffraction. The melting poiat of sucrose (anhydrous) is usually stated as 186°C, although, because this property depends on the purity of the sucrose crystal, values up to 192°C have been reported. Sucrose crystallines as an anhydrous, monoclinic crystal, belonging to space group P2 (2). 

Table 3. Osmotic Pressure of Aqueous Sucrose Solutions at 25°C ...

Polyhydric Alcohols. (Polyols). An alcohol with three or more hydroxyl groups, each attached to a different carbon atom. They are w-sol and of sweetish taste, which tends to intensify with increasing hydroxyl content. Examples of polyols of ordn interest are listed below. Polyvinyl alcohol is considered in a separate entry as a polymer although it is defined as a polyhydric alcohol. Polyols, when nitrated, make excellent expls, proplnt binders, plasticizers, etc. Prepn can follow the procedure of Lenth DuPuis (Ref 3) which uses a methanol suspension of either sucrose or dextrose and a special Cu-Al oxide catalyst to yield 60-65% distillable polyols at 240° and 1500psi Refs 1) Beil — refs found under individual compds 2) CA, under Alcohols, Polyhydric for compds of current ordn interest 3) C.W. Lenth R.N. DuPuis, "Polyhydric Alcohol Production by Hydrogenolysis of Sugars in the Presence of Copper-Aluminum Oxide , IEC 37, 152-57 (1945) CA 39, 1391 (1945)... 

PMT assays were performed as described by Vannier et al. [3] by adding an equal volume of an enzyme preparation to a 0.1 M Tris-HCl buffer containing 3.36 pM of [ C]SAM (1.8 GBq mmol, 740 kBq ml", NEN), 1% (WA ) BSA and 12% sucrose, with or without 0.2% pectic acceptor. The incubation was run at 28°C for 12 h. After precipitation of the reaction product in 70% ethanol, the methylated polymers were selectively extracted with 0.5% ammonium oxalate and radioactivity was measured in a Tricarb 2250 CA Packard scintillation counter. 

Fig. 4.16 Structural parameters of carbon nanocage materials as a function of the sucrose to silica ratio in their synthesis (A) pore diameter (B) specific surface area (C) specific pore volume.

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