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Notes: We have studied the effects of light on high-temperature superconductor microstrip transmission lines under conditions for which a bolometric photoresponse is expected. We illustrate the pitfall of comparing a spatially local property (such as microwave detected photoresponse) and a global property (such as microwave transmission), and then drawing conclusions regarding the bolometric character of the photoresponse. For low microwave powers, the photoresponse, measured as function of the position of the spot illuminated, provides a measurement of the spatial inhomogeneity of the microwave properties of the film. For microwave powers large enough to depress the critical temperature, such measurements provide information about standing waves in the microstrip.

Notes: We report the first radiation effects study on a superconducting ring resonator made from thin-film YBa2Cu3O7−δ. Exposure to 2 MeV protons causes the superconducting transition temperature Tc to decrease predictably with fluence. For temperatures below about 0.9Tc , there is no significant change in the transmission coefficient, the center frequency, or the quality factor Q of the resonator, even for doses in excess of 4×1016 protons/cm2 (∼0.04 displacements per film atom). Similarly, the low-temperature surface resistance Rs of an unpatterned film does not change with irradiation. We show that this insensitivity to radiation is not predicted by standard theory, and that the dominant part of Rs at low temperature is the residual resistance R0. Thus any viable theory describing the origin of R0 must, as a criterion, explain the origin of its insensitivity to large irradiation doses. This criterion is used to evaluate theories ascribing R0 to weak links, flux pinning, impurities, and lattice imperfections.

Notes: Abstract The aim of the present study was to evaluate possible associations between subgingival plaque bacterial morphotypes, as assessed by darkground microscopy, and clinical indices of routine adult chronic periodontitis. Clinical indices were plaque index (PII), gingival index (GI), sulcus bleeding index (SBI), papilla bleeding index (FBI), attachment loss (AL), pocket depth (PD) and probeable pocket depth (PPD). Apical border plaque was sampled in vivo and after extraction to test whether direct or indirect sampling affected any such associations. Similarly, pocket depth and attachment loss were also assessed directly and indirectly on the same teeth, in vivo or after extraction. The influence of the type of index used to record inflammation (GI, SBI, PBI) was also assessed, as were the effects of the numbers of sampled subjects and the method of analysis, which comprised the use of transformed and untransformed data and of parametric and non-parametric tests. Data were collected in relation to the approximal surfaces of 44 teeth extracted from 22 adults (2 teeth each) and from 1 pair of contralateral upper anterior or premolar teeth in each of 100 adults, all which untreated routine chronic periodontitis. Selected subjects had ≤4 mm probeable pocket depth and/or attachment loss, and radiographic evidence of bone loss in relation to 1 approximal surface on each of 1 pair of contralateral anterior or premolar teeth, or to 2 teeth scheduled for extraction. Plaque preparation and darkground microscopy were as described previously. Insignificant associations (P 〉 0.05) were demonstrated between supragingival plaque (P1I) and periodontal inflammation (GI, SBI, PBI) or destruction (PPD and AL), as well as between inflammation and attachment level. In contrast, significant moderate associations (r= 0.5–0.77) were demonstrated between each of the 3 morphotype groups; spirochaetes, other motiles and cocci. Spirochaetes showed a significant moderate (r= 0.5) positive association with pocket depth with a 2.43% mean increase of spirochaetes for each 1 mm increase of PPD. Although highly significant associations (r= 0.9) were demonstrable between the 3 inflammation indices (GI, SBI, PBI) themselves, only PBI showed significant positive associations (r= 0.3) with spirochaetes and other motiles. Also, P1I showed significant associations with each of the 4 morphotypes (r= 0.3–0.5). The heterogeneity of spirochaetes and other motiles as well as the multiplicity of possible aetiological microbial agents in plaque may have resulted in underestimated associations between subjects as well as undetectable association within a given mouth using only 4 morphotype groups. Method of plaque sampling, pocket depth, attachment loss or inflammation assessment did not generally affect the results. Nor did data transformation or statistical method used significantly enhance the strength of demonstrated associations.

Notes: Abstract The present study comprises an investigation of 7 different probe types, representing currently-marketed major designs (WHO-CPITN, Williams, Michigan), as well as available calibration systems (engraved, etched and painted markings). Width of markings, accuracy of calibration from probe tip, and tine diameter at the tip and at specified points along the tine were assessed, using a stereomicroscope at a magnification of × 40. Blind duplicate measurements of these probe tine characteristics were 100% reproducible to within 0.01 mm. There was an overall range in marking width from 0.00–1.13 mm. The best marking, in that it had no appreciable width and the highest accuracy, was the discrete transition between normal and engraved parts of probes with engraved bands. Mean inaccuracies of different probe sets varied from 0.06 to 0.22 mm. Probes from the same batch from the same production line could differ by more than 0.5 mm in calibration. Mean tip diameter ranged from 0.28 to 0.70 mm. It was concluded that probe tine diameter and calibration should be considered in addition to other variables of periodontal probing. Standardisation of tine characteristics and avoidance of the use of different types or batches in a single study should enhance the accuracy and reproducibility of periodontal probe-dependent measurements.

Notes: Abstract We have explored the effect of 2-MeVH+ irradiation on the superconducting transport properties of thin films of YBa2Cu3O7−δ [T c, Jc(B=0; 77 K, 4.2 K), andR s(36 GHz;T)]. The inductively measured critical temperatureT c changed slowly and uniformly (∼2 K per 1016/cm2) for fluences less than ∼3×1016/cm2. Beginning at ∼3–4×1016/cm2, the superconducting transition broadened and dropped more quickly with fluence. The critical current density measured at 77 and 4.2 K changed roughly linearly with fluence. The microwaveT c (as defined by the sharp transition inR s as a function of temperature) resembled the low-frequency inductiveT c measurement at low fluences but was depressed more strongly for large fluences. The residual surface resistance (∼6–10 mΩ) was not affected for fluences up to 5×1016/cm2. We have interpreted the sudden and reproducible reduction in the microwaveT c transition as a sensitive indicator of disruption in the copper-oxygen chain sublattice and compared the proton-induced change to that observed in oxygen gettering studies of bulk materials.