Search

A 13-year-old boy had cardiomyopathy, marked peripheral muscle atrophy and weakness, mild peripheral neuropathy, and mild cerebellar signs. At autopsy, axonal spheroids made up of aggregates of neurofilaments were found in the dorsal gray horns and dorsal columns of the spinal cord, in the tegmentum of the medulla, and in the dorsal spinal roots. A cardiomyopathy was present with targetlike (“targetoid”) fibers consisting ultrastructurally of electrondense material intermingled with fine fibrillary elements. Similar but less extensive changes were seen in the skeletal muscles. This case may represent a new disease entity resulting from an unknown metabolic defect that affects both the neural axons and the muscular tissue at a common basic level and produces abnormalities in the structure and physiology of the contractile elements of the affected tissue.

Owing to its special significance in being the backbone constituent of a class of natural abundant and relatively complex sesquiterpenes,1 the bicyclo[5.3.0]decane (hydroazulene) ring system has drawn extensive attention to its synthesis in recent years.2,3,4 We wish to report a novel and efficient synthesis of functionalized hydroazulenes wherein a two carbon ring expansion was achieved by using a photochemical approach (see Scheme)5. In addition to its simplicity, the current method differs from the existing ones2,3,4 in that it provides a direct access to functionalizing both rings of the hydroazulene skelton-such a feature is of special interest for a great majority of hydroazulenic sesquiterpenes, the presence of functionalities in both the five- and the seven-membered rings are common.1

The photodecomposition of 1,1,1-trichloro-2,2-bis(5′-chloro-2′-methoxyphenyl)ethane (MPA) has been carried out both in solution and solid phase with exciting light > 300 nm. The major products of the solid phase photolyses are HCl and 1,1-dichloro-2,2-bis(5′-chloro-2′-methoxyphenyl)ethylene (MPE), 5,5′-chloro-2,2′-methoxybenzophenone (MPO), 1,1-dichloro-2,2-bis(5′-chloro-2′-methoxyphenyl)ethane (MPD), and 1-chloro-2,2-bis(5′-chloro-2′-methoxyphenyl)ethane (MPC). In liquid phase and in the presence of O2the photodecomposition yields many products, the major ones, in addition to HCl, being MPE, MPD, MPC, and MPO. In the absence of O2in liquid phase only HCl, MPD, MPC, and MPE were observed. In the O2free photolysis MPD and MPC are produced in larger quantity than MPE. A preliminary investigation has shown that MPE irradiated at λ > 300 nm also photodecomposes. A check carried out by the Canada Department of Agriculture indicates that MPA is a pesticide although it may not be as effective as DDT.

Extract: Maximal rate of renal tubular reabsorption of glucose (TmG) was determined in a 9-month-old girl with congenital intestinal malabsorption of glucose and galactose associated with constant glucosuria. At the time of the procedure, the patient had attained normal growth and development and was enjoying good health following a 5-month dietary regimen which excluded virtually all carbohydrates other than fructose. The standard glucose titration of renal tubules was carried out, using 4 arterial plasma glucose concentrations (PG), each maintained over 3 consecutive 20-minute periods while the glomerular filtration rate was kept relatively constant. The following observations were made: 1. The rate of filtered glucose (FG) was found to exceed that of reabsorption (TG) at all PGlevels ranging from 31 to 243 mg%, revealing a very low renal plasma threshold. 2. A TmGof 76.7 mg/min/1.73 m2was achieved at a PGlevel of 174 mg%, when FG/TG= 1.35. This amounts to 25% of the normal adult value, taken as 303 mg/min/1.73 m2. Compared with data on premature and full-term newborns, it reflects a profound deficiency of tubular reabsorption of glucose in our patient. 3. A marked drop of TGwas recorded during the final hour of titration with prolonged elevation of FG; and the observation was felt to be valid. A search of the literature revealed that others have observed the same phenomenon in subjects with suboptimal tubular reabsorption of glucose relative to the filtered load.Speculation: The finding of a low TmGin our patient with documented intestinal malabsorption of glucose and galactose strengthens Crane's original concept that a common mechanism mediates active transport of glucose at the intestinal and renal tubular epithelia. The marked drop of TGafter prolonged elevation of FGin subjects with suboptimal tubular reabsorption of glucose seems to reflect a sudden ‘fatigue’ or inhibition of an already strained transport mechanism. It is postulated that this propensity for ‘fatigue’ or inhibition, by whatever processes, may be part of the profile of defective epithelial transport of glucose in these patients.

Based on the elastic interaction between a solute atom and a tensile crack-tip stress field, a mechanism of stress-corrosion cracking was proposed and analyzed. This elastic interaction provides a potential for solute atoms to migrate toward the tip of a crack. The elastic interaction and the equilibrium concentration of solute atoms near a crack tip were calculated. The solute atom concentration increases rapidly toward the crack tip if the solute atom is interstitial or if it relaxes the crack-tip stress field. The high concentration of solute atoms at the tip of a crack will enhance the reaction between solute and solvent atoms. The weak fracture strength of the reaction product may cause crack growth. Two crack growth models were analyzed: One is based on the assumption of the “homogeneity” of the fracture and deformation properties of a material, and the other takes a structural size of a material into consideration. The proposed models are compared with available data on magnesium-aluminum alloy, 4340 steel, and soda-lime glass.

An experimental and analytical investigation was undertaken to study the fundamental factors of crack propagation in a thin metal sheet under repeated axial loading. Sheet specimens of 2024-T3 aluminum alloy containing a central hole were used in the experimental investigation. Stress range and mean stress were the controlled parameters. An expression for crack length was derived, based on the concept of geometric similarity of crack configuration, for a semi-infinite sheet subjected to repeated loads consisting of a constant stress and mean stress. The expression is in terms of a stress dependent propagation factor and an exponential function of the number of cycles of loading. The expression for a semi-infinite sheet was modified for crack propagation in a specimen of finite width. Accurate predictions of the propagation life was possible using the modified equation. Photomicrographic observations of the crack tips were made.

Photo-cycloaddition of vinyl acetates to 2-cyclohexenones followed by hydrolysis of the acetate group and by oxidative fragmentation leads to 2-alkyl-2-cyclohexenones in which the newly introduced alkyl group bears a 2′-carbonyl group. A similar, less generally applicable method, involving photo-cycloaddition, bromination, and heterolytic fragmentation is also described. Possible applications of this sequence in organic synthesis are discussed.

In spite of the fact that a number of methods are available for the preparation of C-5-monoalkylated (simple alkyl) cyclopentenones1, general synthetic routes leading to cyclopentenones possessing an activated side chain at C-5 remain virtually unknown2. In connection with our synthetic studies on iridoids3, we have developed a convenient synthesis of the title compounds which we wish to report herein.

Using the saturation of hysteresis energy absorption as a criterion for fatigue crack propagation, the rate of crack propagation in a thin and wide metal sheet under repeated axial loading is found to be proportional to the square of the applied stress range. The local stress and strain fields adjacent to the crack tip are employed to compute the energy density. The analytical results correlate very well with the experimental results on 2024-T3 aluminum alloy.

A total synthesis of dilactam (3) possessing the complete pentacyclic skeleton of the Ormosiaalkaloids has been completed.

The alkaloids of Ormosiasemicastratahave been shown to be (−)-ormosanine, (±)-piptanthine, (−)-18-epiormosanine, and (−)-ormocastrine. The structure and relative configuration shown in 1have been assigned to ormocastrine on the basis of its 220 MHz n.m.r. spectrum and its conversion to ormosanine, among other products, on hydrogenation.