Thermophysical properties of silicate slags

The optimization of metallurgical processes requires reliable data of the slag phase. This paper focuses on three properties that are relevant to heat and mass-transfer calculations — viscosities,thermal diffusivities, and surface tensions of silicate melts. A brief account of the experimental techniques used for the measurements of these properties, with special reference to the work carried out in the Division of Metallurgy, Royal Institute of Technology, Stockholm, Sweden, are presented, along with the advantages and limitations. As these properties are structure-oriented, the impact of structure on these properties is also presented. The paper is intended as a state-of-the-art review of the subject.     

Hygiene-related and feed-related hoof diseases show different patterns of genetic correlations to clinical mastitis and female fertility

Hoof diseases are a problem in many dairy herds. To study one aspect of the problem, genetic correlations between 4 hoof diseases, protein yield, clinical mastitis, number of inseminations, and days from calving to first insemination were estimated in first-parity Swedish Red cows using trivariate linear animal models. Occurrence of dermatitis, heel horn erosion, sole hemorrhage, and sole ulcer were reported by hoof trimmers. The data set contained about 314,000 animals with records on at least one of the traits; among these, about 64,000 animals had records on hoof diseases. Heritabilities were low for all hoof diseases (0.03 to 0.05). The hoof diseases fell into 2 groups: (1) dermatitis and heel horn erosion (i.e., diseases related to hygiene) and (2) sole hemorrhage and sole ulcer (i.e., diseases related to feeding). The genetic correlations between traits within the 2 groups were high (0.87 and 0.73, respectively), whereas the genetic correlations between traits in different groups were low (≤0.23). These results indicate that the 2 groups of hoof diseases are partly influenced by the same genes. All genetic correlations between hoof diseases and protein yield were low to moderate and unfavorable. Moderate and favorable genetic correlations were found between the feed-related hoof diseases and clinical mastitis (0.35 and 0.32), whereas the genetic correlations between the hygiene-related hoof diseases and clinical mastitis were low and not significantly different from zero. The genetic correlations between the hygiene-related hoof diseases and number of inseminations were low to moderate and favorable (0.32 and 0.22), and the genetic correlations between the feed-related hoof diseases and number of inseminations were low and not significantly different from zero. A moderate genetic correlation was found between sole ulcer and days from calving to first insemination (0.33), whereas the genetic correlations between days from calving to first insemination and sole hemorrhage and the hygiene-related hoof diseases were low and not significantly different from zero. In general, the 2 groups of hoof diseases showed different patterns of genetic correlations to the other functional traits, but both were unfavorably correlated to protein yield. A simulation study showed that inclusion of hoof diseases in the selection index will not only reduce the genetic decline in resistance to hoof diseases but also be favorable for other functional traits and improve overall genetic merit.     

Carpal tunnel syndrome and hand edema in temporal arteritis

An 89 year-old male was admitted to hospital presenting oedema, reduced sensibility, paraesthesia and reduced mobility of both hands. EMG was in accordance with bilateral carpal tunnel syndrome. An elevated sedimentation rate was found and biopsy from the temporal artery showed arteritis. During glucocorticoid treatment the symptoms disappeared and the EMG and sedimentation rate returned to normal.     

Reproducibility of w/c ratio determination from fluorescent impregnated thin sections

The ease and reproducibility of preparing fluorescent epoxy impregnated thin sections for w/c determination of concrete has been studied. Five sets of thin sections were prepared from 6 concrete mixes having different compositions and w/c ratios (0.35 to 0.80). The thin sections were prepared by different technicians and produced over a period of nearly a year. The quality of the thin sections was checked and the w/c ratio determined by seven petrographers using fluorescent light microscopy as a Round Robin test.The investigation showed that, within a reasonable time, different technicians were able to produce a comparable quality of fluorescent epoxy impregnated thin sections, even though the thin sections were produced from concrete at different ages and using different equipment and chemicals. The petrographers were able to distinguish between the green shades of the fluorescent dye epoxy impregnated cement paste, with sufficient accuracy. The result of the w/c Round Robin test gave standard deviations between 0.02 and 0.03 (average 0.026).     

Effects of incentive programs to stimulate safety belt use: A meta-analysis

The effects of campaigns using tangible incentives (rewards) to promote safety belt usage have been evaluated by means of a meta-analytic approach. Two coders extracted a total number of 136 short-term and 114 long-term effect sizes and coded many other variables from 34 journal articles and research reports. The results show a mean short-term increase in use rates of 20.6 percentage points; the mean long-term effect was 13.7 percentage points. Large scale studies report smaller effect sizes than small scale studies; when studies were weighted by the (estimated) number of observations, the weighted mean effect sizes were 12.0 and 9.6 percentage points for the short and long term, respectively. The main factors that influence the magnitude of the reported short-term effect of the programs were the initial baseline rate (which was highly correlated with the presence or absence of a safety belt usage law), the type of population involved, whether incentives were delivered immediately or delayed, and whether incentives were based on group or individual behaviour. Together these four variables accounted for 64% of the variance. Other variables, such as the duration of the intervention, the probability of receiving a reward, and the value of the reward were not related to the short-term effect sizes. The relationship between moderating variables and long-term effects was less clear.     

Inhibition of LPS and Plasmodium falciparum induced cytokine secretion by pentoxifylline and two analogues

An efficient sporulation/immobilization procedure for immobilized fungal cell culture was developed by modifying an existing immobilized technique to shorten the time and number of steps for sporulation. This method was applied to an immobilized-cell perfusion bioprocess (IPB) for continuous production of CyA, an intracellular secondary metabolite produced by a filamentous fungus, Tolypocladium inflatum. In the IPB, the fungal cells were immobilized in the pores of celite beads (100-500 microm) and a top-driven stirred tank fermentor was used for the culture. The IPB showed good process benefits as demonstrated by the high density of immobilized cells continuously producing CyA-containing free cells. The productivity of cyA-containing free cells in the effluent was very high, ca. 1.0g/(L/h) at a dilution rate of 0.1 h-1, due to the high density of immobilized cells in the fermentor. The CyA productivity was 4.0-6.0 mg/(L/h) which was about 6-10-fold higher than that of batch suspended cell culture. Such an efficient IPB was possible since a decantor was developed in this study, which could effectively separate cell-immobilized beads from the effluent although bead loss slightly increased as the cell loading increased in the latter part of culture. Furthermore, long-term operation of IPB was carried out successfully by employing an in-situ immobilization strategy. It was found that a large number of spores in the fermentation broth in the reactor were entrapped in-situ into the newly supplemented celite beads and then germinated, thus forming new immobilized cells.     

Are there differences between ‘visual symptoms’ and specific ocular symptoms associated with video display terminal (VDT) use?

To assess the reliability of self-reported symptoms of asthenopia associated with VDT use (as characterized by general visual symptoms, headache and specific ocular symptoms) for both continuing soft contact lens (SCL) wearers and former SCL wearers who had undergone successful laser-in-situ-keratomileusis (LASIK) surgery. METHODS: Forty generally healthy adults, aged between 24 and 44 years, were asked to complete a 13 page questionnaire that included requests for information on general visual symptoms, headache and specific ocular symptoms such as dry eye associated with VDT use. The adults were either long term successful soft contact lens wearers (n=20) or a similar group who had then undergone successful LASIK refractive surgery for myopia 2 years prior to the questionnaire being provided. RESULTS: Most subjects (70%) reported experiencing some visual symptoms sometimes, 62.5% reported headaches sometimes, and 82.5 % reported specific ocular symptoms sometimes. There were no obvious differences between the two groups either in the reported frequency or severity (by visual analogue scale, VAS) of visual symptoms, headache or specific ocular symptoms. However, while the reporting of headache showed no obvious association with the number of specific ocular symptoms reported, the latter showed a clear correlation with the reporting of the severity of visual symptoms (p<0.001). DISCUSSION: The results indicate that when an individual reports visual symptoms, they may actually be providing recall of specific ocular symptoms. Therefore, contrary to an often common practice, visual symptoms should be assessed separately to specific ocular symptoms such that the appropriate management can be selected. The results also indicate that previous contact lens wearers who have undergone successful LASIK are still likely to experience some visual and specific ocular symptoms when undertaking computer based work on a regular basis.     

Bottom up process improvement tricks

Most everyone in our field acknowledges that software process improvement cannot succeed unless management is committed to implementing it. Fortunately, the move to SPI can be a two-way street, initiated as easily from the bottom up as from the top down. Taking this bottom-up approach, I present some tricks that practitioners down in the trenches can use to win upper management's approval of and support for SPI     

Natural infection of cowpea (Vigna unguiculata (L.) Walp.) by toxigenic fungi and mycotoxin contamination in Benin, West Africa

Natural infection of cowpea by toxigenic fungi and mycotoxin contamination in Benin, West Africa were studied. Cowpea samples were collected at harvest (T₀) and after three months of storage (T₃) from the four agro-ecological zones of the country. A total of 92 representative samples were analysed for the two periods. About 23 fungal species were identified on cowpea seed samples across zones of which Aspergillus flavus, a fungus that produces aflatoxins, was most frequently encountered. Fusarium species shown to produce fumonisins were not recorded from cowpea seeds. Overall incidence of A. flavus infection was found to increase after storage from 7.6% at T₀ to 28.25% at T₃. In spite of this natural infection of cowpea, very low levels of fumonisin and aflatoxin were detected. Only three out of the 92 cowpea samples, all collected at T₀, were found to be fumonisin B₁ positive with a mean level of 0.03 μg/g. Similarly, only six samples out of the 92, all collected at T₃, were aflatoxin B₁ positive with mean levels of 3.58 μg/kg. Fumonisin (B₂ and B₃) and aflatoxin (B₂, G₁ and G₂) were not detected in any of the samples. Contrary to the situation with maize and groundnut where high levels of toxin are often detected in naturally infected samples, the current results indicate that cowpea is less susceptible to mycotoxin contamination. A low susceptibility could be due to the presence in cowpea of substances that inhibit mycotoxin biosynthesis. Further investigations are underway to confirm this hypothesis.