Chylothorax: report of a case complicating ductus ligation through a median sternotomy, and review

An unusual case of chylothorax is described in a 4-year-old child after repair of a ventricular septal defect and ligation of a patent ductus arteriosus through a median sternotomy. Left chylothorax developed after a latent period of six days and was treated initially with continuous drainage and parenteral supplementation of proteins and lipids. Operative intervention with oversewing of the site of the leak in the anterior mediastinum proved necessary after three weeks. The anatomical variations of the thoracic duct are outlined to explain the occurrence of chylothorax after diverse intrathoracic operations. The physiological effects of a thoracic duct fistula and various aspects of management are reviewed.     

Procedures for the evaluation of the long term strength of plastics and some results for polyvinyl chloride

Some of the problems associated with the study of failure are reviewed and exemplified by results on two commercial grades of PVC. The whole range of failure phenomena, from crazing to fracture, and the effect of notches on durability is discussed. A test schedule involving minimum experimental effort for the evaluation and comparison of the long term durability of thermoplastic materials is proposed.     

Experiments on the use of a laser beam for heat detection

Earlier papers discussed the theory of using lasers for fire detection and described a system that was subsequently developed. The authors report on experiments with the system, which indicate that laser detection system performance is comparable with that of a heat-sensitive point detector of maximum sensitivity permitted by British Standard 3116.     

Composition control of batch copolymerization reactors

Composition control of free-radically initiated batch copolymerization reactor by temperature manipulation is investigated through a program of calcula and experiment. The work of Ray and Gall is extended to explicit calculation of temperature vs time policies which eliminate or minimize composition dr Both continuous and discrete, piecewise-constant policies have been computed. The former are disjoint policies which can be found simply by manipulatin monomer mass balances; the latter are found through application of the discrete version of the maximum principle. Calculations are compared to experime done on the system styrene-acrylonitrile. It is demonstrated that implementation of some of the computed policies is feasible and quite beneficial. The discrete policies with small numbers of stages (less than ～six) perform much more poorly than the continuous policies indicating that the copolymeriz reactor is much more sensitive to deviations from optimality than batch reactors operating with other reaction schemes. Thus, effective implementatio tracking a continuous trajectory.     

Cyclic creep of type 304 stainless steel during unbalanced tension-compression loading at elevated temperature

Samples of Type 304 stainless steel were subjected to cyclic stresses with a positive mean stress at 300 and 560°C. Very rapid net elongation was observed whenever the stress limits were such as to produce a plastic strain amplitude of the same order of magnitude as the elastic strain at the peak stress. The maximum mean strain-rate, or cyclic creep rate, for a given peak tensile stress was achieved when the mean stress was just slightly above zero. Increasing the mean stress caused the mean strain rate to de-crease. The sensitive dependence of the mean strain-rate on the plastic strain ampli-tude and inverse dependence on the mean stress indicates that remobilization of disloca-tions by the reverse strain is an important mechanism for cyclic-creep acceleration. Although rapid cyclic creep was observed at both temperatures, a measurable mean strain rate was found for a much narrower range of stress conditions at 560 than at 300°C. The strain accumulated during cyclic creep did not produce any strain hardening, but did influence the shape of the stress-strain curve in a subsequent tensile test.     

Fiber-foam: A rheological phenomenon and a novel product

When certain molten thermoplastics containing glass fibers up to 20 mm in length are extruded through an orifice, the extrudate has a frothy texture and solidifies into an irregular open-cell structure. The effect is apparently caused by the recovery of the fibers from distortions arising in the region of converging flow near the entry to the orifice. The effect is particularly pronounced in systems with melt viscosities between 50 and 500 Ns/m². Polypropylene, as an example, containing weight fractions of about 0.25 of glass fibers can be extruded through a zero-length die 2 mm in diameter to give “ropes” that can be readily formed into flat sheets or three-dimensional shapes because of adhesion between the still molten polymer in the newly extruded rope. Such sheets can then be bonded to other materials to make a variety of laminates. A range of bonding techniques is available and the rough surface texture of the ropes provides a useful mechanical key for bonding with grossly dissimilar materials. Fiber-foam is highly resistant to fracture and has a modulus in the range expected by a simple model for the foam.     

Preemployment predictors of union attitudes: Replication and extension.

Replicates and extends the J. Barling et al (see record 1992-07316-001) model of family socialization of union attitudes on the basis of data from 87 students and their parents. Students' union attitudes were predicted by students' Marxist work beliefs and their perceptions of parental union attitudes. Students' perceptions of parental union attitudes and participation were predicted from parents' self-reported attitudes and participation. Students' Marxist work beliefs were not related to parents' work beliefs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cold shortening and cooking changes in beef

Quantitative relationships have been established between pre-rigor shortening in beef sternomandibularis muscle and cooking shrinkage and weight loss. Shortening induced by cold increases cooking weight loss and shrinkage across the meat grain, but reduces shrinkage along the fibre direction. The mechanism of fluid discharge from meat on cooking is determined by the degree of pre-rigor shortening. In unshortened meat, cooking shrinkage along the fibre precedes discharge and transverse swelling occurs to accommodate entrapped fluids. During the cooking of highly shortened meat, fluid discharge occurs mainly across the fibres, the sarcolemmas of which presumably have been split during shortening. Consequently early swelling on cooking does nccur.     

CD19 as a membrane-anchored adaptor protein of B lymphocytes: costimulation of lipid and protein kinases by recruitment of Vav

Germ cells are distinct from somatic cells in their immortality, totipotency, and ability to undergo meiosis. Candidates for components that guide the unique germline program are the distinctive granules observed in germ cells of many species. We show that a component of germ granules is essential for fertility in C. elegans and that its primary function is in germline proliferation. This role has been revealed by molecular and genetic analyses of pgl-1. PGL-1 is a predicted RNA-binding protein that is present on germ granules at all stages of development. Elimination of PGL-1 results in defective germ granules and sterility. Interestingly, PGL-1 function is required for fertility only at elevated temperatures, suggesting that germline development is inherently sensitive to temperature.