Free and open‐source automated 3‐D microscope

Open‐source technology not only has facilitated the expansion of the greater research community, but by lowering costs it has encouraged innovation and customizable design. The field of automated microscopy has continued to be a challenge in accessibility due the expense and inflexible, noninterchangeable stages. This paper presents a low‐cost, open‐source microscope 3‐D stage. A RepRap 3‐D printer was converted to an optical microscope equipped with a customized, 3‐D printed holder for a USB microscope. Precision measurements were determined to have an average error of 10 μm at the maximum speed and 27 μm at the minimum recorded speed. Accuracy tests yielded an error of 0.15%. The machine is a true 3‐D stage and thus able to operate with USB microscopes or conventional desktop microscopes. It is larger than all commercial alternatives, and is thus capable of high‐depth images over unprecedented areas and complex geometries. The repeatability is below 2‐D microscope stages, but testing shows that it is adequate for the majority of scientific applications. The open‐source microscope stage costs less than 3–9% of the closest proprietary commercial stages. This extreme affordability vastly improves accessibility for 3‐D microscopy throughout the world.     

COLLAGEN CHARACTERISTICS AND MEAT TEXTURE OF PIGS EXPOSED TO DIFFERENT LEVELS OF PHYSICAL ACTIVITY

Intramuscular collagen and meat texture were measured in 23 female and 23 entire male pigs, subjected to one of three treatments: individual housing in pens of 2.5 m² (confined; C), individual housing and regular treadmill training (trained; T) and group housing equal to 0.9 m²/animal (free; F).
Treatment T tended (P = 0.13) to increase the activity of citrate synthase (CS) in M. biceps femoris (BF) from female pigs. Moreover, the heat stability of collagen and the mechanical resistance to 60 and 80% compression were increased (P<0.03) in BF from female pigs in treatments T and F as compared to C. In BF from male pigs, treatment T decreased (P = 0.03) the heat stability of collagen when compared to C and F. Sensory tenderness was not affected (P>0.05) by physical activity, however. In BF from female pigs, CS activity, collagen content and resistance to compression were lower (P<0.01) than in male pigs. In M. longissimus thoracis et lumborum, there was no effect of either physical activity or sex. Depending on muscle type and sex, physical activity affects meat texture.     

N-Nitrosodibutylamine and other Volatile Nitrosamines in Cured Meat Packaged in Rubber Nettings

Results from investigations of N-nitroso-n-dibutylamine (NDBA) in cured meat are compared from investigations in Denmark, the USA and Canada. NDBA was detected in very few samples and in quantities that were very low. Cured meats packaged in plastic wrappings or cotton nettings did not contain any NDBA. All cured meat packaged in elastic rubber nettings on the Danish market cannot contain more than 0.5 ppb NDBA.     

THE MUNICIPAL BOND MARKET HEADS IN NEW DIRECTIONS

This essay charts the recent changes in the municipal bond market. Trends in the size and composition of tax-exempt borrowing over the last 20 years and the burden of debt and quality of credit are briefly reviewed. The nature of investor demands and fluctuations in tax-exempt rates of interest are also discussed. Emphasis is placed on the changing forms of security and the growth of special purpose borrowing. The transformation of tax-exempt borrowing from its traditional role of raising capital for government capital facilities to one of acting as financial intermediary is noted and the implications of this development are contemplated.     

The stability of Clostridium botulinum type E toxin in salty and/or acid environment

The stability of preformed Clostridium botulinum type E toxin in sterile buffer-and salt-solutions and in some commercial fish products has been examined. It has been found that progenitor toxin is stable for weeks at room temperature in sterile culture filtrate, spoiling fish and in low acid fish products and that it is unaffected by sterile saturated salt (NaCl) solutions and in salted fish. In high acid feed fish (fish silage pH 2–4) some inconsistant increased toxin titres have been observed.
The activated toxin, on the other hand, decreased and increased in titre during several weeks of storage in culture filtrate with added trypsin. In sterile NaCl solutions the titre decreased by a factor of 10 to that of a progenitor toxin, but in spoiling raw and salted fish toxicity was lost when pH exceeded 7.5.
The public health significance of these results is discussed.     

Systematic Study of Simple Titania-Bearing Porcelain Enamels

An extensive composition study of titania enamels and their properties is described. The compositions investigated contained only six constituents, namely, Na₂O, K₂O, SiO₂, B₂O₃, TiO₂, and F₂. Systematically and over a wide range, the contents of SiO₂, B₂O₃, TiO₂, and alkali were varied. One hundred enamels in all were made and the resulting properties were determined. Properties noted included flow, expansion, color, percentage of anatase, gloss, reflectance, and acid resistance at various firing temperatures.
Enamel Y12, representing a small area in this large composition field, exhibited the properties requisite for a good hollow–ware white cover–coat enamel. Compared with previously studied titania enamels, this enamel is "softer"; i.e., it fires at lower temperatures, has the desired higher flow and expansion, yet still possesses the required properties of color stability, reflectance, gloss, acid resistance, and workability.     

FINITE ELEMENT REMESHING: A METAL FORMING APPROACH FOR QUADRILATERAL MESH GENERATION AND REFINEMENT

The paper presents an automatic finite element remeshing system for quadrilateral elements consisting of modules for mesh generation, densification, smoothing and interpolation of field variables. The mesh generator takes into account the contour of the old mesh, eventual interference with dies and the plastic deformation of the material. An initial coarse mesh is created by utilizing a grid-based approach for creating well-shaped internal elements, in conjunction with a nodal connection approach based on constrained Delaunay triangulation, for linking with the boundary. Subsequent local mesh refinement is performed according to parameters depending on past, present and predicted future deformation related field variables; being, respectively, the strain gradient and strain rate distribution in relation with the velocity field, element size and quality. Smoothing is accomplished using an iterative Laplacian repositioning method. As illustrated in the presented examples this overall strategy ensures a robust and efficient remeshing scheme for finite element simulation of bulk metal-forming processes. © 1997 by John Wiley & Sons, Ltd.     

Color Stability of Clear and Opaque Titania Enamels Containing Various Color Oxides

A study was made of the spectrophotometric characteristics of a clear and an opaque titania-bearing enamel. Three and six per cent additions of green, blue, brown, and red oxides were made to the base enamels. After firing the enameled samples over a range of time and temperature, spectrcphotometric and X-ray data were obtained. The results indicate that the lack of stability of the opaque colored enamels is due to the change from a blue-white to a cream-white color on increased firing treatment. The addition of a cream component tends to shift the hue of the fired enamel toward the red end of the visible spectrum. The green and the blue colors were much less stable than the red. X-ray data show that the total anatase present decreases, which is evidence that a cream-white color developed. X-ray data did not indicate any change in crystal structure of the anatase, rutile, or color oxide. Titania present in the glass of the clear enamel did not cause color instability.     

Inter-process synchronization in steel production

The development of strategies for sequencing slabs through the reheat furnace and rolling mill of a modern steel production facility is complicated by multiple, and often conflicting production objectives. Optimal energy efficiency through the reheat furnace may lead to inefficient rolling sequences or less than desirable product delivery schedules. Not only is model formulation complicated, but the combinatorial nature of the problem precludes optimal solution. A heuristic procedure for solving this multi-objective product sequencing problem has been developed and tested under production conditions in a Danish steel mill. The methodology, which is based on a modified ‘greedy’ algorithm is presented and results using actual production data are discussed