Insight into the local density of states at Si sites at the submonolayer Si/Ge(001)-2 × 1 interface from Si KLV Auger spectroscopy.

An analysis of the differences observed between the Si KLV Auger spectra of the Si/Ge(001)-2 × 1 interface and pure Si indicates that the electronic structure of the interface is characterized by a reduction in the local p DOS at the Si sites and a transfer of p valence charge from Si to Ge. As a result, the screening of core-ionized Si sites at the interface is significantly shifted towards s screening compared with the situation for pure Si. It is possible that there is an increase in the on-site electron correlation energy, UP, for Si sites at the interface as compared with pure Si.

Reflection anisotropy spectroscopy of the oxidized diamond (001) surface.

We report reflection anisotropy spectroscopy (RAS) measurements of the oxidized (001) surface of a type IIb natural diamond. These measurements were made possible due to recent developments in diamond surface preparation. We compare RAS results from the hydrogenated, clean and oxidized C(001) surface and demonstrate that RAS is sensitive to the structural transition of the surface from the 2 × 1 reconstruction of the clean surface to the 1 × 1 reconstruction of the oxidized surface.

Hyaluronidase production in Streptococcus milleri in relation to infection.

One hundred and seven (41%) of 262 isolates of Streptococcus milleri, from human sources, produced hyaluronidase. Hyaluronidase production was commoner in beta haemolytic isolates 32 of 39 (82%), many of which were of Lancefield group F. But hyaluronidase was also found in alpha and non-haemolytic isolates, and in groups A, C, G, and non-groupable isolates. There was a strong association between hyaluronidase production and isolation from known internal abscesses (48/58, 83%) compared with isolates from the normal flora of uninfected sites (24/97, 25%). Isolates from 15 patients with endocarditis were uniformly negative, although 13 of 25 (52%) isolates from dental plaque produced the enzyme. Production of hyaluronidase may therefore be an important determinant in the pathogenicity of infection by S milleri and could be helpful in predicting the likelihood of deep purulent lesions in isolates from blood culture.

Neonatal mycoplasmaemia: Mycoplasma hominis as a significant cause of disease?

A full-term baby boy had respiratory distress, fever and pneumonia within 20 h of birth. Isolation of Mycoplasma hominis from blood taken after 20 h and 11 days was accompanied by an antibody response. Although chlamydial IgM antibody was detected, chlamydial infection probably did not cause the pneumonia. Penicillin was ineffective but treatment with gentamicin, and particularly tetracycline, was associated with slow improvement. Mycoplasma hominis should be considered as a cause of respiratory disease and fever in neonates.

The isolation of streptococci from human faeces.

Three selective media were designed for isolation of streptococci from faeces. Samples of faeces from twelve normal adults were suspended and serially diluted in saline or broth saline, and equal volumes of each dilution were spread and incubated on the media. The number of colonies of each different type which developed was counted and one colony of each type was subcultured and identified. Altogether, streptococci of 13 taxa were found. S. faecium, S. mutans, S. milleri, S. faecalis and S. mitior were each found in over half the samples. Lancefield group B and G streptococci, S. bovis II, an atypical strain of S. bovis I, S. cremoris, S. durans and a dextran-positive strain of S. mitior were each present in 1 or 2 samples. Individual samples contained 2-7 (mean 4.6) streptococcal taxa, and total viable counts of streptococci of 3 X 10(3)-3 X 10(8) (geometric mean 7 X 10(5)) per g. The significance of these findings is discussed.

Precision field averaging NMR magnetometer for low and high fields, using flowing water.

The separated oscillatory field magnetic resonance technique (Ramsey technique) has been employed with flowing water as a volume averaging magnetometer. Polarization and detection were performed in high fields, external to the volume over which the magnetic field was to be averaged. An accuracy of a few parts in 10(7) at a nominal field of 18 G was obtained. The technique is applicable, using standard equipment, for the measurement of fields ranging from kilogauss down to milligauss.

An assessment of the Microcult-GC culture test.

Microcult-GC, a miniaturised culture test, was compared with an established selective culture method for laboratory confirmation of gonorrhoea. Microcult-GC correlated 94% with the control method in identifying gonococci in male urethral specimens. Microcult-GC testing of 130 gonococci-negative vaginal swabs gave only 4.6% false-positive oxidase results, which could probably have been readily refuted by Microcult Gram stain. The test may be difficult to interpret for rectal specimens and is not appropriate for pharyngeal cultures.

Flucloxacillin in bone.

Ten patients undergoing total hip replacement for osteoarthritis were each given intramuscular flucloxacillin about two hours preoperatively; bone and serum were sampled simultaneously at operation. Trabecular and compact bone were separated, partly dried, reduced to powders, and then extracted with buffer. The concentration of flucloxacillin in bone washings and serum was determined by well-diffusion assay. The mean concentration of flucloxacillin in serum was 8.9 mg/l, in trabecular bone washings, 1.3 mg/l, and in compact bone washings 0.9 mg/l. The amount of blood contaminating the bone washings was measured, and was calculated to account for at most 26% of the flucloxacillin present. The significance of these findings is discussed in relation to the prophylactic use of flucloxacillin in hip replacement surgery.