Optical and Mechanical Properties of New Ceramic CAD/CAM Materials.

OBJECTIVE: The purpose of this study was to compare the optical and mechanical properties of newer ceramic CAD/CAM materials to more established materials on the market. METHODS AND MATERIALS: The following ceramic materials were tested: lithium disilicate/lithium-aluminum silicate (Tessera, Dentsply/Sirona), lithium disilicate (Initial LiSi Block, GC), IPS e.max CAD, Ivoclar Vivadent), and 4Y polycrystalline stabilized zirconia (IPS e.max ZirCAD MT, Ivoclar Vivadent; Katana STML, Kuraray; YZ ST, VITA). Optical properties (translucency, opalescence) were determined using a dental spectrophotometer on 0.5-, 1.0-, 1.5-, or 2.0-mm specimens. Mechanical properties (flexural strength, flexural modulus, flexural fatigue strength, Weibull modulus, and characteristic strength) were determined with beams undergoing 3-point bend testing. The data were analyzed with multiple analyses of variance and Tukey's post hoc tests (α=0.05). RESULTS: Significant differences were found between groups based on type of ceramic or property (p<0.05). CONCLUSIONS: In general, the lithium disilicate based-ceramic materials had greater optical properties and lower mechanical properties than the zirconia-based ceramic materials.

Heatwave hyponatraemia: a case series at a single Victorian tertiary centre during January 2014.

Heatwaves are a major public health threat for Australians. Hyponatraemia is common, with an increased incidence previously described during heatwaves. We report a series of 10 patients admitted with moderate to profound hyponatraemia, the majority with a history of excess water consumption, during the January 2014 heatwave.

Stepped-heterodyne optical complex spectrum analyzer.

We present a heterodyne measurement of the spectral amplitude and phase of periodic optical signals. In contrast to previous techniques this measurement requires no optical modulation of either the signal or the local oscillator, places much relaxed tunability requirements on the optical local oscillator, and requires no electronic clock to be passed to the receiver. We present measurements of the spectral amplitude and phase of 20 GHz 33% return-to-zero, and 66% carrier-suppressed return-to-zero optical signals, as well as a passively modelocked optical source with in excess of 100 modes.

The vibrational spectrum of the stable free radical 1,1,3,3-tetramethylisoindolin-2-yloxyl.

Solid and solution IR and Raman spectra of a stable nitroxide radical, 1,1,3,3-tetramethylisoindolin-2-yloxyl (TMIO), are reported and compared to ab initio density functional theory calculations of the vibrational frequencies to obtain unequivocal band assignments, in particular of the NO stretching frequency, nu(NO). The band position was found to be at 1431 cm(-1) for the solid, which is well outside the previously published range of 1310-1380 cm(-1) for nitroxide radicals. This apparently anomalous peak position was confirmed by undertaking isotopic substitution studies through the preparation and recording of vibrational spectra of tetrakis(trideuteriomethyl)isoindolin-2-yloxyl ([2H12]-TMIO) and [2H12,15N]-TMIO analogues. Solution spectra of TMIO in methanol and CCl4 are assessed for possible solvent-dependent spin density distribution effects in the NO bond.

Manipulation of the cervical spine.

In New Zealand, a new approach to manual therapy of the cervical spine has integrated physiotherapy and osteopathy techniques. The combination of the philosophies of these two professions has added a new dimension to the management of cervical spine pain. Emphasis is placed on issues of safety, such as the degree of cervical rotation and comfort for both the patient and the therapist. This is combined with biomechanical considerations, which have made the teaching and learning of these manipulative techniques less complicated and easily progressed from palpation to mobilization and onto manipulation. Appropriate patient screening and selection identified through thorough subjective and objective assessments are important aspects of this approach and reflective interpretation of all clinical findings is essential. The refinement of cervical joint positioning and an increased anatomical awareness have led to the utilization of new upper cervical high-velocity thrust techniques. Consequently, it is envisaged that an increase in the safety and specificity of cervical manipulative techniques is achieved.

Spontaneous common iliac arteries rupture in Ehlers-Danlos syndrome type IV: report of two cases and review of the literature.

Two patients with previously undiagnosed Ehlers-Danlos syndrome type IV (EDS IV) presented acutely with clinical features suggestive of hypovolemic shock. Emergency laparotomies in both of them revealed spontaneous rupture of the common iliac arteries. The clinical features, operative findings, surgical approach, outcome and implications are discussed.

Electrospray ionization mass spectrometry of stable nitroxide free radicals and two isoindoline nitroxide dimers.

Electrospray ionization (ESI) mass spectra were recorded for a range of substituted isoindoline nitroxides, two isoindoline nitroxide dimers and two piperidinyl nitroxides. In all cases the dominant molecular species arise from oxidation rather than protonation, an unusual process in ESI. Fragment ion spectroscopy was used to establish fragmentation mechanisms for the nitroxides under ESI conditions.

A short measure of perceived empathy.

This paper concerns the development of a short measure of perceived empathy. Developed in the context of research on sales performance, the scale provided indicators for perceived empathy as both a cognitive as well as an affective construct. While not being able to differentiate cleanly between affective and cognitive empathy, the resulting single-factor scale demonstrates good internal consistency and validity, being predictive of successful versus unsuccessful sales encounters.

Characterization and novel activation of 72-kDa metalloproteinase in retinal interphotoreceptor matrix and Y-79 cell culture medium.

Analysis of bovine interphotoreceptor matrix and conditioned medium from human Y-79 retinoblastoma cells by gelatin SDS-PAGE zymography reveals abundant activity of a 72-kDa M(r) gelatinase. The 72-kDa gelatinase from either source is inhibited by EDTA but not aprotinin or NEM, indicating that it is a metalloproteinase (MMP). The 72-kDa MMP is converted to a 62-kDa species with APMA treatment after gelatin sepharose affinity purification, typical of previously described gelatinase MMP-2. The latent 72-kDa gelatinase from either bovine IPM or Y-79 media autoactivates without APMA in the presence of calcium and zinc after 72 hr at 37 degrees C, producing a fully active mixture of proteinase species, 50 (48 in Y-79 medium), 38 and 35 kDa in size. The presence of inhibitory activity was examined in both whole bovine IPM and IPM fractions separated by SDS-PAGE. Whole IPM inhibited gelatinolytic activity of autoactivated Y-79-derived MMP in a dose-dependent manner. Inhibitory activities are observed in two protein fractions of 27-42 and 20-25 kDa. Western blots using antibodies to human tissue inhibitor of metalloproteinase 1 and 2 (TIMP-1 and -2) reveal the presence of two TIMP-1-like proteins at 21 and 29 kDa in inhibitory fractions of the bovine IPM. TIMP-2 was not detected in the inhibitory IPM fractions, consistent with the observed autoactivation of bovine IPM 72-kDa gelatinase. Potential roles for this IPM MMP-TIMP system include physiologic remodelling of the neural retina-RPE cell interface and digestion of shed rod outer segment as well as pathological processes such as retinal detachment, PE cell migration, neovascularization and tumor progression. Cultured Y-79 cells appear to be a good model for studying the production and regulation of this proteinase system.

Early clinical results of long coronary arteriotomy, endarterectomy and reconstruction combined with multiple bypass grafting for severe coronary artery disease.

Within a 2.5-year period between 1985 and 1988, long coronary arteriotomy, endarterectomy and reconstruction (principally left anterior descending artery) and multiple bypass grafting (mean graft rate was 9) were performed in 130 of 329 patients (40%) with severe diffuse coronary artery disease to ensure complete myocardial revascularization. Ninety-two percent of the patients who underwent exercise testing had abnormal (greater than 1 mm ST) depression and/or positive results on scintigraphy. Long coronary arteriotomy (5 to 12 cm), endarterectomy and reconstruction of the left anterior descending artery and its branches, were performed in 121 patients; of the left circumflex artery and its branches in 13 patients; and of the right coronary artery and its branches beyond the crux in 18 patients. Single endarterectomy and reconstruction was performed in 109 patients, double in 20 and triple in 1. The operative mortality was 2.3% and the perioperative infarction was 1.5%. Twenty-four patients (among them 38% who had undergone greater than 1 previous bypass operation) were randomly selected and studied within 20 days after surgery. This group comprised a total of 69 coronary conduits of which 68 (99%) were patent, and a total of 206 coronary anastomoses of which 202 (98%) were patent. Thirty-two of 33 conduits (97%) to endarterectomized and reconstructed arteries were patent. One hundred and twenty-six of 127 patients were followed up for a mean of 20 months; 120 of the 121 patients (99%) were in angina class I by Canadian Cardiovascular Society classification, and 63 of 71 patients (89%) had a normal treadmill exercise stress test.(ABSTRACT TRUNCATED AT 250 WORDS)

Knowledge of schoolchildren about the acquired immune deficiency syndrome.

Teenage schoolchildren are often sexually active and first experiments with drugs can occur at this age. A questionnaire survey of the knowledge and source of information about the acquired immune deficiency syndrome was carried out on 232 15-year-olds at a school in Fife. The results showed that this younger age group is well-informed about AIDS, particularly methods of transmission of the virus, and that the majority of information was obtained from television (95%) and leaflets (85%).

Comparative use of cold blood potassium cardioplegia in coronary bypass patients necessitating long (2.5-6 h) versus short (less than 1.5 h) aortic cross-clamp times.

In symptomatic patients with severe diffuse multivessel coronary disease undergoing bypass surgery, complete revascularization with multiple bypass grafts using saphenous vein and internal mammary conduits, and multiple endarterectomies may be necessary. Such complex surgeries may require long aortic cross-clamp times in excess of 2.5 h. To evaluate the myocardial preservation provided by cold potassium blood cardioplegia, two groups of consecutive patients using nearly similar surgical techniques were compared. Group A consisted of 100 patients who received an average of 3.8 grafts per patient and had a mean aortic cross-clamp time of 66 (range 15-90) min. Group B was comprised of 100 patients who received an average of 9.3 grafts per patient and had a mean cross-clamp time of 187 (range 150-351) min. Operative mortality and perioperative myocardial infarction were low (0-2%) and were not significantly different between the groups. In addition, the postoperative creatine kinase-MB isoenzyme levels, use of pharmacologic and/or mechanical (i.e., intra-aortic balloon) support, and follow-up exercise treadmill tests were not significantly different in the two groups. These findings suggest that cold potassium blood cardioplegia is equally protective of the myocardium during surgical revascularization in patients with short aortic cross-clamp times (less than 1.5 h) as in those with severe diffuse multivessel coronary artery disease requiring long cross-clamp times exceeding 2.5 h and up to 6 h.

Multiple (more than eight) bypass grafts in severe diffuse coronary disease: improved exercise tolerance and functional classification in seventy-seven consecutive patients.

During a 43-month period (May 1981 to December 1984), 77 consecutive patients underwent multiple (eight or more) coronary artery bypass procedures using saphenous vein conduits for severe diffuse triple-vessel coronary artery disease. Patients received from 8 to 14 grafts (average 9). All coronary arteries and branches that were at least 1.5 mm in diameter and greater than 50% obstructed were bypassed. The operative mortality rate was 1.3%. Seventy-six of 77 (98.7%) patients are alive at a mean follow-up of 2 years. According to the Canadian Cardiovascular Society Angina Criteria, before surgery 5 patients (6%) were classified class I, 8 (10%) class II, 43 (56%) class III, and 21 (27%) class IV. After surgery all 76 patients were class I. Of 59 patients who had undergone bypass surgery who were followed by exercise testing according to the modified Bruce protocol, 47 exercised to greater than or equal to 85% heart rate. Among these patients, 44 (94%) had a normal exercise test result and only 3 had greater than or equal to 1 mm ST segment depression. Thus, patients with severe diffuse coronary disease can undergo multiple (eight or more) bypass grafting procedures with low mortality rates and improved exercise tolerance and functional classification.

Sternal dehiscence: pericostal guy wires equals sternal stability.

Our five-year clinical experience with 11 patients treated with pericostal guy wires has uniformly established sternal stability, primary bone healing, and rapid resolution of infection. The stable anterior chest wall helps abolish cardiopulmonary complications (i.e., progressive pulmonary insufficiency, atelectasis, and low cardiac output) commonly associated with sternal dehiscence.