On the Elevated Temperature Thermal Stability of Nanoscale Mn-Ni-Si Precipitates Formed at Lower Temperature in Highly Irradiated Reactor Pressure Vessel Steels.

Atom probe tomography (APT) and scanning transmission electron microscopy (STEM) techniques were used to probe the long-time thermal stability of nm-scale Mn-Ni-Si precipitates (MNSPs) formed in intermediate and high Ni reactor pressure vessel steels under high fluence neutron irradiation at ≈320 °C. Post irradiation annealing (PIA) at 425 °C for up to 57 weeks was used to determine if the MNSPs are: (a) non-equilibrium solute clusters formed and sustained by radiation induced segregation (RIS); or, (b) equilibrium G or Γ2 phases, that precipitate at accelerated rates due to radiation enhanced diffusion (RED). Note the latter is consistent with both thermodynamic models and x-ray diffraction (XRD) measurements. Both the experimental and an independently calibrated cluster dynamics (CD) model results show that the stability of the MNSPs is very sensitive to the alloy Ni and, to a lesser extent, Mn content. Thus, a small fraction of the largest MNSPs in the high Ni steel persist, and begin to coarsen at long times. These results suggest that the MNSPs remain a stable phase, even at 105 °C higher than they formed at, thus are most certainly equilibrium phases at much lower service relevant temperatures of ≈290 °C.

Screening for malignant melanoma using instant photography.

OBJECTIVE: To assess the use of instant photography, in addition to clinical grading, as a method of screening for malignant melanoma during routine health examinations. SETTING: A health screening clinic with an average throughput of about 12,000 patients a year. METHODS: Suspicious pigmented skin lesions were judged clinically using the revised seven point checklist scoring system. They were then photographed with a Polaroid camera and the prints were graded independently by two consultant dermatologists with a special interest in malignant melanoma. A copy of the print was also given to the patient to keep for observation of any change in the lesion. RESULTS: Over a 45 month period 39,922 patients of both sexes were screened and 1052 skin lesions were clinically assessed and photographed. Fourteen malignant melanomas were diagnosed--all, except one, were thin lesions with a good prognosis. CONCLUSIONS: The clinical opinions of non-dermatologists using the revised seven point checklist proved disappointing in screening because of the large number of benign lesions that were given high scores. Photography, on the other hand, detected 11 melanomas and succeeded in separating the majority of banal lesions from potentially malignant ones, thus greatly reducing the need for specialist referral. Nevertheless, three melanomas were missed on purely photographic grading, which emphasises the danger of placing too much reliance solely on a two dimensional image. Finally, the possession of a personal copy of the photograph by the patient proved popular and led to a diagnosis of melanoma in two instances. This procedure merits further study.

A hypothesis for the molecular mechanism of tumor killing by porphyrins and light.

Tumor cells have an absence or deficiency of mitochondrial superoxide dismutase. Superoxide is produced when hematoporphyrin derivative is exposed to visible light. A significant portion of the antitumor effect of porphyrin:light therapy is hypothesized to be mediated by superoxide.

An economic justification of "blitz" therapy to eradicate Streptococcus agalactiae from a dairy herd.

Streptococcus agalactiae was identified as the cause of mastitis in a 240-cow dairy herd. Forty-five per cent of the herd had cell counts over 500,000/ml, and 28 per cent had cell counts over 1,000,000/ml. Dry cow therapy was used regularly but teat dipping had not been used for three years. The procedures at milking were modified, teat dipping was introduced, and the herd was divided into two according to cell count. The 120 cows with higher cell counts were treated with 300 mg erythromycin (Erythrocin intramammary; Sanofi Animal Health) preparation per quarter at two consecutive milkings. Towards the end of lactation, all the 90 lactating cows in the herd were again treated with erythromycin. Milk samples were collected from all the cows in the herd 12 months after the initial treatment, and S agalactiae was isolated from only one replacement heifer which had been purchased after the treatments with erythromycin. The butterfat and protein levels in the milk were compared with those of a similar, but untreated, herd for 12 months before and after therapy. The butterfat levels rose sharply after treatment, and financial assessment showed a 41 per cent return on investment in the 12 months following the treatment.

Raised herd somatic cell count due to Staphylococcus aureus following the failure of an automatic teat spraying system.

This study describes the failure of a single jet exit race automatic teat spray (ATS) system resulting in the spread of Staphylococcus aureus infection in a 135-cow dairy herd, which showed an increased herd somatic cell count from 91,000/ml to 554,000/ml over a nine-month period. S aureus was isolated from 34 of 46 high cell count cows. The milking procedures were modified and manual teat spraying was restarted. Bacteriology was used to identify S aureus positive high cell count cows, and first and second lactation cows were treated during lactation. If their cell counts were not reduced, these were then culled. High cell count S aureus cows in lactation three or above were culled. The three-month geometric mean cell count fell to below 150,000/ml within five months. As all replacements were home-bred, S aureus infection must have spread from within the herd itself. All other causes have been eliminated, and this spread is attributed to the failure of the ATS to carry out effective postmilking teat disinfection. The advantages and disadvantages of ATS systems are discussed, especially in relation to robotic or voluntary milking systems.

Aortic valve replacement in a case of Ehlers Danlos syndrome.

A case of Ehlers Danlos syndrome is described in a 54-year-old Caucasian male. He had calcific aortic valve disease and dilatation of the ascending aorta. An aortic valve replacement was performed using a Starr prosthesis.

Direct spectrofluorophotometric determination of porphyrin in diluted urine.

Direct dilution of freshly passed urine with 19 to 99 volumes of an acid-alcohol solution of chloranil (2, 3, 5, 6-tetrachloro-1, 4-benzoquinone) results in rapid and apparently quantitative conversion of porphyrinogen to fluorescing porphyrin. Dilution must be sufficient to yield an essentially colorless solution. Under these conditions, excitation of fluorescence by 401--405 nm light and fluorescence analysis at 652 nm results in almost complete elimination of quenching and of non-specific fluorescence under the conditions described. Fluorescence intensity is relatively stable for up to several weeks. Alternatively, urine is added to NaHCO3 to permit quantitative conversion of porphyrinogen to porphyrin in 1 to 2 days, and assayed similarly following dilution with the same acid-alcohol diluent (with or without chloranil) or with dilute HCl solution alone. Quantitative results are shown to agree well with those obtained following purification by other, more tedious, procedures. The method has been tested successfully with urines from humans, cows, and rats.