The spatial distribution and spectral characteristics of field-induced electron emission sites on broad-area high voltage electrodes

Instrumental techniques are described for displaying (a) the spatial distribution of field emission sites on planar high voltage electrodes and (b) the emission current pattern within an individual site. Typically, emission ‘sites‘ are generally composed of three or more ‘sub-sites’ that become temporally unstable at current > 10^?7 A. The electron energy spectra of sub-sites are characteristically single peaked, whose half-widths (FWHM) initially vary linearly with applied field: from changes in spectral area with field, substantially linear sub-site F-N plots have been obtained having β values in the range 300–500.     

Metastatic parathyroid carcinoma in the MEN2A syndrome

We report a patient with a metastatic parathyroid carcinoma and medullary carcinoma of the thyroid. This patient represents a variation of the multiple endocrine neoplasia syndrome (MEN) type 2A. There was no evidence of a phaeochromocytoma. The case illustrates the difficulties that may be encountered in localising the source of PTH secretion; the patient underwent four unsuccessful exploratory operations of the neck and mediastinum before further investigations revealed a single metastatic deposit of parathyroid carcinoma involving the first thoracic vertebra. PCR amplification and sequencing of the RET oncogene from the metastatic parathyroid carcinoma and genomic DNA revealed a heterozygous mutation (Cys634Tyr) in exon 11, as has previously been described to occur in MEN 2A. In addition, loss of tumour heterozygosity was demonstrated at loci from chromosomes 1, 2, 3p, 13q and 16p. This represents the first report of a parathyroid carcinoma in a MEN2A patient, in which the multiple allelic deletions are consistent with the generalised losses observed in aggressive tumours.     

Premature introduction of progestin-only contraceptive methods during lactation

INTRODUCTIONS: Cochlear implants are used for the rehabilitation of bilaterally deaf patients. Due to the improvements in speech processing they might be also useful for patients with residual hearing and some speech understanding. METHODS: Pre- and postoperative speech understanding scores in 26 patients receiving implants were evaluated in a retrospective study. RESULTS: The preoperative pure-tone threshold in the implanted ear was between 80 and 115 dB in the frequency range of 500 to 2000 Hz. On the contralateral side the mean threshold was 10 dB better. The mean score for the number test was 11.3%, for the monosyllables below 5%. Postoperatively speech understanding improved significantly up to 97% for numbers and 48% for monosyllables (tested with the Freiburger Speech Test). Cochlear implantation also benefits patients with residual hearing and some speech understanding with hearing aids under optimum conditions. The speech understanding scores must be below certain limits. General selection criteria cannot yet be specified. The individual decision must be based upon several criteria, especially the speech understanding scores in quiet and noise under optimum conditions. A prospective study is needed to develop generally applicable criteria.     

Incisional hernia after laparoscopic nephrectomy with intact specimen removal: caveat emptor

The choline-containing phosphoglycolipid, MfGL-II, is the major polar lipid of Mycoplasma fermentans PG18. Anti-MfGL-II antisera raised in rabbits using the purified MfGL-II as an immunogen were employed in immunogold electron microscopic and immunofluorescence studies showing that MfGL-II is uniformly distributed and exposed on the cell surface of M. fermentans cells. The specificity of the antibodies was determined by immunostaining of lipid extracts separated by thin layer chromatography. The antibodies recognize lipids specific to M. fermentans but did not cross-react with lipid extracts of M. penetrans, M. capricolum, M. gallisepticum or Acholeplasma laidlawii. As phosphocholine almost completely abolished antibody interaction with MfGL-II in an ELISA assay it is suggested that the anti-MfGL-II repertoire is composed primarily of anti-phosphocholine antibodies. The anti-MfGL-II antisera inhibit the attachment of M. fermentans to Molt-3 lymphocytes suggesting that MfGL-II plays a major role in M. fermentans-host cell interaction.     

The dusty atmosphere of the brown dwarf Gliese 229B

The brown dwarf Gliese 229B has an observable atmosphere too warm to contain ice clouds like those on Jupiter and too cool to contain silicate clouds like those on low-mass stars. These unique conditions permit visibility to higher pressures than possible in cool stars or planets. Gliese 229B's 0.85- to 1.0-micrometer spectrum indicates particulates deep in the atmosphere (10 to 50 bars) having optical properties of neither ice nor silicates. Their reddish color suggests an organic composition characteristic of aerosols in planetary stratospheres. The particles' mass fraction (10(-7)) agrees with a photochemical origin caused by incident radiation from the primary star and suggests the occurrence of processes native to planetary stratospheres.     

The impact of hypothermia on dilutional coagulopathy

The control of hemorrhage in hypothermic patients with platelet and clotting factor depletion is often impossible. Determining the cause of coagulopathic bleeding (CB) will enable physicians to appropriately focus on rewarming, clotting factor repletion, or both. Objective: To determine the contribution of hypothermia in producing CB and ascertain if simultaneous hypothermia and dilutional coagulopathy (DC) interact synergistically. Method: Prothrombin time, partial thromboplastin time, and platelet function were determined at assay temperatures of 29 degrees to 37 degrees C on normal and critically ill, noncoagulopathic (NC) individuals. Dilutional coagulopathy was created using buffered saline and the assays repeated. Results: Hypothermic assay at < or = 35 degrees C significantly prolonged coagulation times. The effect of hypothermia on NC and DC samples was not different. Conclusion: Assays performed at 37 degrees C underestimate coagulopathy in hypothermic patients. The effect of hypothermia on NC and DC is not different, indicating the lack of a synergistic effect. Normalization of clotting requires both rewarming and clotting factor repletion.     

Effects of high oxygen concentrations on microbial biosensor signals. Hyperoxygenation by means of perfluorodecalin

Amperometric biosensors register oxygen depletion in response to analyte catabolism, and thus are limited by the availability of dissolved oxygen. Microbial sensors containing immobilized cells of Gluconobacter oxydans were hyperoxygenated to 400% of control levels and the effects on sensor responses to glucose were determined. Oxygenated perfluorodecalin (a completely fluorinated organic substance) was as effective in hyperoxygenation as direct sparging with O2, increasing sensor base medium oxygen concentrations from 9.3 to 37 mg/l. Hyperoxygenation enhanced maximal biosensor response amplitudes, particularly at high cell loading densities. Maximal response rates were also improved, although less dramatically. Results suggest that hyperoxygenation may be a new general approach for modulating biosensor responses.