Terahertz reflectivities of metal-coated mirrors

Terahertz (THz) reflectivities of a variety of metal-coated mirrors were measured. Gold, silver, and aluminum coatings were tested and compared. It was found that all types of optical metal-coated mirrors perform equally well as THz reflectors.     

The mineral composition of apples. V.—The determination of sodium and its distribution in the fruit

The determination, with an E.E.L. flame photometer, of sodium in the seeds, pulp, peel and stems of apples is subject to errors owing to the presence of calcium, potassium and magnesium. In the absence of phosphate, values which are too high by as much as 50% may be obtained. Phosphate is present in the ash of the seeds, pulp and peel of Cox's Orange Pippin apples in amounts sufficient to suppress completely the effect of calcium, but the amount in the ash of the stems is insufficient to do so and errors of about 10% may arise. The sum of interferences due to potassium and magnesium in the ash of any part of the apple results in positive errors of up to 7%. Apart from slight variations near the surface, sodium concentrations in median transverse sections of apples rise from the surface of the fruit to a maximum at 5 mm inside and then fall towards the centre. The variations within the outer 3 mm appear to be characteristic of individual apples and unrelated to orchard treatment and time in store.     

Plant virus-induced changes in aphid population development and temporal fluctuations in plant nutrients

Cucurbita pepo plants were infected with zucchini yellow mosaic virus or maintained noninfected.Aphis gossypii, which transmits the virus, lived longer and produced more offspring on infected than on noninfected plants. On infected plants, the intrinsic rate of natural increase forA. gossypii increased with time after inoculation. In a similar experiment, concentrations of phloem sap nutrients, including free amino acids, total protein, and sugars from infected and noninfected plants were compared for 37 days after inoculation. Significant differences in levels of individual amino acids from phloem exudate between infected and noninfected plants were found, yet the concentration of total amino acids was not substantially different between infected and noninfected plants. Beginning four days after inoculation, the total protein content of phloem exudate generally was lower in infected plants than noninfected plants. Likewise, the total sugar content of phloem exudate from infected plants was lower than that of noninfected plants beginning nine days after inoculation. In contrast with the results from analyses of phloem exudate, foliage from infected plants had higher levels of almost all amino acids than noninfected foliage beginning nine days after inoculation. Concentrations of individual and total amino acids in infected foliage increased throughout the experimental period. Although no temporal effects were observed in the foliage sugar content for either individual or total sugars, starch content decreased with time in infected plants, while in noninfected plants, starch content remained level.     

Influence of male rats on the luteinizing hormone-releasing hormone neuronal system in female rats: role of the vomeronasal organ

Olfactory information processed by the vomeronasal system is reported to influence reproductive functions in a variety of mammals. The present studies were designed to determine if male-associated cues affect the luteinizing hormone-releasing hormone (LHRH) neuronal system, and, if so, to determine the extent to which these cues are processed by the vomeronasal organ (VNO). Ovariectomized rats underwent VNO removal (VNX) or sham surgery (VN-Sham). Forty-eight hours after estrogen priming (5 micrograms), they were subjected to one of the following treatments: repeated mating, repeated exposure to male-soiled bedding or repeated exposure to clean bedding. In animals treated for 180 min, coronal brain sections were double labelled for Fos protein and LHRH. An intense Fos immunoreactivity was induced following mating in the majority of LHRH neurons in the VN-Sham females, whereas removal of the VNO significantly suppressed the mating-induced Fos staining. Exposure of female rats to male-soiled bedding or clean bedding did not induce appreciable Fos immunoreactivity in LHRH neurons. Following 90 min of mating or exposure to bedding, blood samples were assayed for luteinizing hormone (LH). Mating stimulated the release of LH in VN-Sham females, while the removal of the VNO significantly suppressed the mating-induced LH release. Exposure of the females to male-soiled bedding or clean bedding did not induce an LH surge. The present results demonstrate that male-originating sensory cues (i.e. repeated mating) can influence the LHRH neuronal system, as evidenced by the presence of Fos immunoreactivity in LHRH cell bodies, and indicate that this effect is mediated through the VNO to a certain extent.(ABSTRACT TRUNCATED AT 250 WORDS)     

Phospholipid coatings for the prevention of membrane fouling

The aim of the present work was the development of phosphorylcholine-based treatments for biofiltration membranes and the demonstration that such treatments prevent or inhibit protein fouling. Microfiltration membranes of cellulose triacetate, polyether sulphone and polyvinylidene fluoride were etched with oxygen in a plasma chamber to generate surface hydroxyl groups and were then treated with the monomer 2-methacryloyloxyethyl phosphorylcholine. These membranes were evaluated with water, buffer, bovine serum albumin (BSA), yeast fermentation broth, beer and orange juice. The treatment of cellulose triacetate membranes reduced both the initial flux and the extent of water fouling. In terms of the integrated flux, these factors tended to cancel each other out. For protein, the membranes gave similar or higher fluxes but worse fouling. The cellular feed (yeast) reacted more favourably to the coating than the BSA. The polyether sulphone was scarcely affected by the coating; fouling remaining high with most ‘real’ feeds. There was lower initial flux but less flux decline with water and beer. Washing with water and cleaning with Tergazyme did not restore the initial flux. Polyvinylidene fluoride membranes gave the most positive results. In most cases, the coating both increased initial flux and decreased the rate of fouling. The coating was particularly effective for BSA and for beer and orange juice, where fouling is probably caused by a polysaccharide rather than by a protein. Electron microscopy showed, nonetheless, that fouling by proteins was accompanied by protein adsorption primarily on the upper surface of the membrane and that coated membranes showed less deposition and in different places than did untreated membranes.     

Packaging and world class competitive products

The aim of the Irish food industry is to produce world class competitive products (WCCPs). Stating the obvious: Food and packaging are inseparable and thus WCCP status is a target also for packaging manufacturers in their own right and also as to how packaging assists food companies to achieve their aims.     

Lenticel blotch pit,watercore, splitting and cracking in relation to calcium concentration in the apple fruit

Analyses of apples, of various varieties and from many sources, affected by lenticel blotch pit and/or watercore showed that calcium concentrations in the fruit were usually extremely low. The severity of lenticel blotch pit, either on the tree or during storage, increased with decreasing concentrations of calcium and/or increasing concentrations of potassium. Split and cracked apples had lower concentrations of calcium or higher concentrations of potassium than sound fruit from the same sources. The disorders usually occurred when mean concentrations of calcium in bulked random samples of fruit fell below 4 mg 100 g^?1 fresh wt and lenticel spotting was noted on apples with concentrations at this level. Incidences of these disorders in the orchard therefore indicate that the fruit is likely to develop bitter pit and breakdown during storage.     

Consequences of surprising reward omissions.

A surprising reward omission (SRO) occurs when an appetitive reinforcer is not presented (or it is reduced in magnitude or quality) even though there are signals for its impending presentation. Evidence supporting the hypothesis that SROs produce an aversive emotional reaction with physiological and behavioral consequences is reviewed. SROs are followed by pituitary-adrenal activation; changes in immune function; odor emissions in rodents; distress vocalizations in rodents and primates; and increases in locomotion, aggressive behavior, drinking, and eating. SROs can support the acquisition of new escape responses and invigorate previously acquired responses. The review identifies common aspects of these phenomena and areas in which more research is needed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comments on "Spheroidal vector wave eigenfunction expansion of dyadic Green's functions for a dielectric spheroid" [and reply]

Dudley and Johnson (see ibid., vol.50, p.XX XX, Nov. 2002) comments that Li, Leong, Kooi and Yeo (see ibid., vol.49, p.645-659, April 2001) formulate in detail the dyadic Green's functions for the dielectric spheroid stating that one result of their derivations, the singularity of the electric Green's dyadics is extracted. They also comment that there is nothing formally wrong with extracting the delta function. They object strongly, however, to the authors stating that they have extracted "the singularity of the electric Green's dyadics." They have not done so. Li et. al. reply that they, are grateful for the comments of Dudley et. al clarifying the singular behavior of the electric and magnetic field Green's dyadics. They intended to state "irrotational part of the electric dyadic Green's function" which is highly singular, but misused the term, "singularily of the dyadic Green's function".