Loss of renal tissue in the elderly

Eighty-eight kidneys obtained at necropsy from normotensive subjects aged over 50 years were examined histologically and by post-mortem pyelography and angiography. Moderate or severe scarring was present in 50%. Its distribution and the absence of calyceal deformity make pyelonephritic scarrig unlikely. Its extent was related to the severity of change in the renal vessels, but not to age. On pyelograms, scarring was difficult to distinguish from fetal lobation. Kidneys with the most severe histological changes in the vessels tended to show the most marked angiographic distortion, though in general the two techniques examine different parts of the renal vascular bed. Total renal area and "cortical" area, measured from the angiograms, were not significantly correlated with age, thouth both tended to be smaller in older subjects. These dimensions, particularly cortical area, were significantly correlated with vascular changes, being smallest when vessels were most markedly affected. Results suggest that the loss of renal tissue which occurs in the elderly, particularly selective loss of cortex, is more closely related to events in the renal vasculature than to age itself.     

Preparation of inside-out vesicles of pig lymphocyte plasma membrane

Between 30 and 50% of pig lymphocyte plasma membrane vesicles were not bound by concanavalin A (Con A)-Sepharose. Various results suggest that the Con A-unretarded fraction represents "inside-out" membrane vesicles. First, an alternative cell surface ligand, anti-lymphocytic serum, gave a similar fractionation to Con A. Second, lack of binding by Con A was not due to lack of carbohydrate or to masking of carbohydrate by extraneous protein, because the unfractionated membrane and the unretarded fraction had similar carbohydrate and polypeptide compositions. Third although the carbohydrate of the unretarded membrane vesicles was accessible to 125I-labelled Con A and to release by soluble trypsin, it was not accessible to ferritin-Con A or trypsin-Sepharose. Fourth, antisera against the external surface of the Con A-unretarded vesicles strongly agglutinated the unretarded membrane, but caused negligible agglutination of whole lymphocytes. When attached to Sepharose these antisera bound all of the Con A-unretarded fraction, but failed to bind the membrane that adhered to Con A-Sepharose.     

Standards for Commutating Capacitors

Problems of standardization exist for capacitors used in power semiconductor equipment. Electronic Industries Association (EIA) has taken a step forward in this area by publishing an industry standard for commutating capacitors. Details of definitions, case types, terminals, ratings, measurements, life tests, performance characteristics, and general applications of these capacitors are covered in the proposed standard. This paper describes part of the EIA program and also includes limited information on the design of commutating capacitors and their use in power semiconductor circuits.     

Response of the european elm bark beetle,Scolytus multistriatus,to host bacterial isolates

The response of the European elm bark beetle,Scolytus multistriatus, to host bacterial isolates was studied qualitatively under field conditions. Initial experiments indicated that such isolates were attractive to in-flight beetles. These isolates, identified asBacillus subtilis (five strains),B. pumilus, andEnterobacter cloacae, were grown on nutrient agar in glass vials and attached to sticky traps in elm woods. Although beetles were caught on the bacterial isolate-baited traps, the catches were variable, inconsistent, and often contradictory from one experiment to another. High numbers ofS. multistriatus were caught on traps baited with three strains ofB. subtilis, but in addition to thesubtilis strains, there were also aerial contaminants in the treatments, namelyE. aerogenes, Corynebacterium sp., andFlavobacterium sp. Also, relatively high catches were recorded on nutrient agar controls. When elm wood-bark plugs, sterilized (by gamma irradiation) and unsterilized, were placed in vials with the host bacterial isolates, the presence or absence of fresh elm, gamma irradiated or not, had no noticeable effect on beetle attractancy.Coleoptera: Scolytidae.     

New criteria for application of the well-mixed model to gas-liquid mass transfer studies

The well-mixed model presents several advantages for the evaluation of interphase mass transfer rates in gas-liquid contactors: it simplifies the mathematical analysis and eliminates the need for measuring numerous mixing parameters. Although the well-mixed model corresponds to a theoretical concept, it is shown in this paper that, under certain conditions, it can be safely applied to the liquid phase of contactors for the purpose of determining the overall volumetric mass transfer coefficient K_La_L. Based on a computer simulation of absorption and mixing processes, simple criteria were developed that specify the conditions for which the well-mixed model is applicable in practice, for either a semi-batch gas-liquid contactor or a continuous flow absorber at steady-state. The dimensionless group K_La_Lτ_c, where τ_c is the average circulation time in the liquid phase of the contactor, was found to be a key parameter in establishing the validity of the well-mixed model.     

C-21 dicarboxylic acids in soap and detergent applications

A unique polycarboxylic acid, 5(6)-carboxy-4-hexyl-2-cyclohexene-1-octanoic acid, has been available commercially for over 15 years. A new high-purity (>97%), light-color version of the C-21 dicarboxylic acid has been developed recently. Soaps of the C-21 dicarboxylic acid can be used as hydrotropes to increase the solubility of nonionic surfactants in aqueous solutions containing builders and/or anionic surfactants. Since these soaps are anionic fatty acid derivatives, they reduce the surface tensions of formulations, thus improving detergency. The nontoxic and biodegradable nature of this dicarboxylic acid makes it an attractive formulation component. This paper outlines application evaluations of the soaps prepared from the C-21 dicarboxylic acids. These evaluations demonstrate how the soaps interact with nonionic surfactants or pine oil to provide clear formulations, how they wet cotton skeins in neutral to highly alkaline solutions, and how they inhibit gel formation when preparing high-solids fatty acid soap solutions. Furthermore, the preparation and characterization of the soaps of the C-21 dicarboxylic acid products are discussed. Mass-balance equations describe the preparation of aqueous soap solutions at any given concentration. Characterization of the resulting soap solutions includes acid number, pH, color, color stability, foam stability, surface tension as a function of concentration, and hard-water compatibility.     

An Iterative Approach to Trustable Systems Management Automation and Fault Handling

Automated systems management solutions aim to reduce the pressure on the administrators of complex, large-scale, distributed systems by enabling the automation of many of the common tasks of management. However, this creates a level of abstraction, which can act as a barrier between the administrator and the elements being controlled. This can impede the transition to new management paradigms required by the increase of off-premise resources and hybrid cloud systems. The resulting loss of control of the managed environment can contribute to a loss of trust in automated systems management solutions and affect their broader use. This paper proposes a novel approach where the administrator can control the automation level on a per task basis. Administrators define a management task as they would perform it directly and allow the solution to identify the triggers that cause the task to be enacted. The solution also allows administrators to define relevant task output that can be analyzed for fault states and enable error recovery without manual intervention. The impact of this approach leads to reduced management effort for the administrator, while retaining controllability and keeping automation costs low, along with reducing the incidence of errors.     

The structure of crosslinked poly(glyceryl methacrylate) hydrogel networks

Poly(glyceryl methacrylate) hydrogels with different degrees of hydration (75–98% H) and cross-linking densities (X = 0.005–0.05 mol tetraethylene glycol dimethacrylate/mol glyceryl methacrylate) have been prepared by solution polymerization. Cross-linking densities of the fully swollen hydrogels were analyzed using a modified Flory equation. Poly(glyceryl methacrylate) gels polymerized with no added cross-linker were found to be highly cross-linked, the degree of cross-linking depending upon monomer dilution at polymerization. Modeling studies indicated that entanglement of polymer chains explained the highly cross-linked nature of these materials. Gels polymerized with tetraethylene glycol dimethacrylate exhibited higher cross-link densities than did gels polymerized with no added cross-linker. However, for gels polymerized with cross-linker, but at different initial dilutions, cross-linking densities varied depending upon initial concentration, indicating that entanglement contributed appreciably to cross-linking. These hydrogels may be regarded as highly swollen entangled networks, contrary to previous views. Correlation of these findings with those from earlier studies on the ultrafiltration behavior of the poly(glyceryl methacrylate) hydrogels suggested that the packing density of polymer fibers in the matrix may be more predictive of ultrafiltration behavior than is mesh size. © 1993 John Wiley & Sons, Inc.     

The density and phase behavior of some binary Hydrocarbon—Nonhydrocarbon systems using new mixing rules for the BWR equation of state

The applicability of the new mixing rules recently formulated by the authors for the BWR equation of state was assessed by predicting the densities of several binary mixtures of hydrogen sulphide with methane and ethane and the phase behavior of the carbon dioxide-propane, hydrogen sulphide-methane, hydrogen sulphide-propane and hydrogen sulphide-carbon dioxide binary systems. The predictions confirmed the effectiveness of the new rules for predicting the densities of hydrocarbon-non-hydrocarbon binaries, and they showed that acceptable accuracy could be obtained in predicting the phase behavior of difficult binary systems even when no phase behavior data are used for evaluating the parameters in the equation of state.