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.

Effect of Various Surface Treatments on Ti-Base Coping Retention.

CLINICAL RELEVANCE: Mechanical surface roughening of the titanium-abutment base is necessary to increase the pull-off bond strength of the lithium disilicate abutment material. Additional chemical surface treatment may further increase the bond strength, but the effects are product specific.

Properties of a New Nanofiber Restorative Composite.

A new nanofiber-reinforced hybrid composite (NovaPro Fill, Nanova) was recently introduced with reportedly improved mechanical properties. The purpose of this study was to compare the properties (flexural strength/modulus, degree of conversion [DC], depth of cure, and polymerization shrinkage) of the nanofiber composite to those of traditional hybrid composites (Filtek Z250, 3M ESPE; Esthet-X HD, Dentsply). To determine flexural strength and modulus, composite was placed in a rectangular mold, light-cured, stored for 24 hours, and then fractured in a universal testing machine. For degree of conversion, composite was placed in a cylindrical mold, light-cured, and stored for 24 hours. Measurements were made at the top and bottom surfaces using Fourier Transform Infrared Spectroscopy. To determine depth of cure, composite was placed in a cylindrical mold and light-cured. Uncured composite was scraped until polymerized resin was reached. Remaining composite was measured and divided by two. Polymerization shrinkage was determined by placing the composite material on a pedestal in a video-imaging device while light-curing. Shrinkage was determined after 10 minutes. Data were analyzed with one-way analysis of variance and Tukey post hoc test per property (α=0.05). Compared to Filtek Z250, NovaPro Fill had significantly lower flexural strength and modulus, greater volumetric shrinkage, and similar depth of cure, but greater top and bottom DC. Compared to Esthet-X HD, NovaPro Fill had similar flexural strength, shrinkage, and top and bottom DC, but significantly greater depth of cure and flexural modulus.

A medical cost estimation with fuzzy neural network of acute hepatitis patients in emergency room.

Taiwan is an area where chronic hepatitis is endemic. Liver cancer is so common that it has been ranked first among cancer mortality rates since the early 1980s in Taiwan. Besides, liver cirrhosis and chronic liver diseases are the sixth or seventh in the causes of death. Therefore, as shown by the active research on hepatitis, it is not only a health threat, but also a huge medical cost for the government. The estimated total number of hepatitis B carriers in the general population aged more than 20 years old is 3,067,307. Thus, a case record review was conducted from all patients with diagnosis of acute hepatitis admitted to the Emergency Department (ED) of a well-known teaching-oriented hospital in Taipei. The cost of medical resource utilization is defined as the total medical fee. In this study, a fuzzy neural network is employed to develop the cost forecasting model. A total of 110 patients met the inclusion criteria. The computational results indicate that the FNN model can provide more accurate forecasts than the support vector regression (SVR) or artificial neural network (ANN). In addition, unlike SVR and ANN, FNN can also provide fuzzy IF-THEN rules for interpretation.

Determinants of Perceived Physical Environment Barriers among Community-Dwelling Elderly in Taiwan.

OBJECTIVES: To test the hypothesis that mobility, activities of daily living, and the interaction between them can play a key role in determining perceived physical environment barriers among community-dwelling elderly. DESIGN: Cross-sectional. SETTING: Community. PARTICIPANTS: One hundred and ninety-seven community-dwelling elderly with more than 7 points on the Short Portable Mental State Questionnaire and less than 7 points on the Geriatric Depression Scale (15 items). INTERVENTION: None. MEASUREMENTS: Time Get-up and Go test (TUG), the subscales of basic activity of daily living (BADL)/instrumental activities of daily living (IADL) of the Hierarchy of Care Required (HCR), and the physical/structural subscale of the Craig Hospital Inventory of Environmental Factors in Community-dwelling Elderly in Taiwan were used to measure mobility, activities of daily living and perceived physical environment barriers, respectively. Hierarchical linear regression analyses were used to test the study hypothesis. RESULTS: Significant and positive relations were found to exist between perceived physical environment barriers and (1) the TUG time (ß=.300, p<.05), and (2) the IADL score for the HCR (ß=.322, p<.05), respectively. A significant and negative relation existed between perceived physical environment barriers and the interaction term (the TUG time and the IADL score for the HCR) (ß=-.211, p<.05). CONCLUSION: Mobility, IADL and the interaction between them are found to be significant determinants of perceived physical environment barriers in the community-dwelling elderly under consideration. Strategies targeting the enhancement of mobility among community-dwelling elderly are suggested to lead to improvements in the degree to which physical environment barriers are perceived. This beneficial effect could be greater in the case of elderly individuals with better IADL function.

Recent trend of pylephlebitis in Taiwan: Klebsiella pneumoniae liver abscess as an emerging etiology.

BACKGROUND AND AIMS: Pylephlebitis (septic thrombophlebitis of the portal venous system) is a rare complication of intra-abdominal infection. We aimed to investigate the recent trend of its etiology, clinical manifestation, and prognosis. METHODS: We retrospectively studied the etiology, clinical manifestation, and outcome by reviewing the medical records of all imaging-confirmed pylephlebitis cases diagnosed during the period 2002-2011 in a university hospital in Taiwan. To identify the risk factors for pylephlebitis, we randomly selected 160 patients with intra-abdominal infections but without pylephlebitis as the comparison group. RESULTS: We identified 35 cases of pylephlebitis. Most patients were men [29/35 (83 %)]. The median age of the patients was 57 years (range 35-90 years). Unspecified abdominal pain (18/35) and fever (10/35) were the most common clinical manifestations. Klebsiella pneumoniae liver abscess (7/35) and cholangitis (7/35) were the most common etiologies. Liver abscess was a risk factor for pylephlebitis (13/35 vs. 27/160, P = 0.01). With antibiotic therapy, there was no in-hospital mortality, but pylephlebitis was still associated with an excess hospital stay (22.2 ± 17.6 vs. 9.8 ± 7.1 days, P < 0.001). CONCLUSIONS: Our study results suggested a different pattern of pylephlebitis from previous Western literature. K. pneumoniae liver abscess (7/35) is an emerging etiology of pylephlebitis in Taiwan.

Redshift of edge emission from AlGaInP light-emitting diodes and correlation with electron-hole recombination lifetime.

The edge emission from AlGaInP light-emitting diodes showed a red-shifted peak in addition to the peak of surface emission. This shift resulted from the quantum-well absorption of the guided wave. Although the shift degrades the color quality and the extraction efficiency of the device, it helps elucidate many important optical properties of the material and the dynamics of carrier recombination, including the electron-hole recombination lifetime, the optical joint density of state, the spontaneous emission spectrum and the absorption spectrum. A simple concept of the bimolecular recombination is established. The corresponding coefficient can be expressed by a simple formula and was therefore determined.

Transgenic cloned mice expressing enhanced green fluorescent protein generated by activation stimuli combined with 6-dimethylaminopurine.

Most studies of mouse cloning successfully achieved activation of the reconstructed oocytes by strontium (Sr) combined with cytochalasin B (CB) treatment. A protein kinase inhibitor, 6-dimethylaminopurine (6-DMAP), was used to inhibit the activity of maturation promoting factor for activation of oocytes, but it has never been successfully applied in mouse cloning. This study investigates the activation efficiency of 6-DMAP in mouse somatic cell nuclear transfer (SCNT). Higher parthenogenetic blastocyst rates (71-72%, p < 0.05) were achieved in the oocytes treated with Sr6D (10 mM Sr combined with 2 mM 6-DMAP for 4 h) and Sr6D + SrCB (Sr6D for 2 h then Sr combined with 5 mug/ml CB for another 2 h), and a higher rate of hatching and hatched blastocyst was observed in the Sr6D + SrCB group (31%, p < 0.01) compared with other treatment groups (1-8%). For mouse cloning, cumulus cells of enhanced green fluorescent protein (EGFP)-expressed ESC chimera F1 were used as donor nuclei. Following activation, better development of the cloned embryos was observed in Sr6D + SrCB treatment. Moreover, different media, i.e. KSOM-AA, MEM-alpha and MK, for culturing cloned embryos were also compared in this study. Better morula/blastocyst (40%) and blastocyst (29%) rates were achieved in the embryos cultured in MEM-alpha medium (p < 0.05). Consequently, four EGFP cloned mice were generated in the activation treatment containing 6-DMAP following embryo transfer. In conclusion, treatment with 6-DMAP in combination with other activation stimuli successfully activates mouse reconstructed oocytes and support full-term development of the transgenic SCNT cloned embryos.

Ring down artefacts on abdominal sonography to predict pulmonary abnormalities in the emergency department.

Ring down artefacts are sometimes found when emergency physicians perform abdominal ultrasound to differentiate between various abdominal problems. We describe a patient who presented with right upper quadrant abdominal pain and whose ultrasound examination showed ring down artefacts posterior to the right hemidiaphragm, which led to the eventual diagnosis of pneumonia. Ring down artefacts on ultrasound may be used to predict pulmonary abnormalities. Awareness of this sonographic finding may assist in accurate diagnosis and administration of appropriate treatment without delay.

Cycloheximide enhances maintenance of methamphetamine-induced conditioned place preference.

Accrued evidence demonstrated the necessity of protein synthesis at acquisition, consolidation and expression stages in conditioning/learning tasks, while the underlying mechanisms of the maintenance of memory remained less explored. This study was designed to characterize the maintenance of methamphetamine-induced conditioned place preference, a drug-induced learning and memory. In addition, cycloheximide, a protein synthesis inhibitor, was used to examine the involvement of protein synthesis in the maintenance of such place preference memory. We found that the maintenance of the rapidly-established methamphetamine (2 mg/kg, i.p.) -induced conditioned place preference could be long-lasting and even over fifty days under the present protocol of extinction. Moreover, it was of interest to note the undulating expression of this conditioned place preference throughout the extinction protocol. Most importantly, as the methamphetamine-induced conditioned place preference was acquired and expressed by mice, the saline-pretreated control mice underwent numbers of intermittent extinction across a long-term retention test period, while cycloheximide-pretreated mice exhibited unaltered methamphetamine-induced conditioned place preference throughout the same retention test period. Taken together, we conclude that [1] methamphetamine-induced conditioned place preference could last for a long period of time, and such place preference memory is reluctant to extinguish even animals' repeated exposure to the previous conditioned environment at a drug-free status, and [2] blockade of protein synthesis may enhance the maintenance of the methamphetamine-induced conditioned place preference.

Global distribution of atrial ectopic foci triggering recurrence of atrial tachyarrhythmia after electrical cardioversion of long-standing atrial fibrillation: a bi-atrial basket mapping study.

OBJECTIVES: The objective of this study was to assess the spatial distribution of atrial ectopic foci potentially triggering recurrent atrial tachyarrhythmias after electrical cardioversion of long-standing atrial fibrillation (AF). BACKGROUND: It remains unknown whether targeted ablation of atrial ectopic foci concentrated in the pulmonary veins is feasible in patients with long-standin

Distinct regulation of genes by bFGF and VEGF-A in endothelial cells.

A finely tuned balance of angiogenic inhibitors and inducers controls the activity of angiogenesis characterized by proliferation, migration and differentiation of endothelial cells. Among many angiogenic factors, basic fibroblast growth factor (bFGF) was first identified to be angiogenic whereas vascular endothelial growth factor A (VEGF-A) is an endothelial cell specific mitogen. In addition to being a specific mitogen, VEGF-A is also known as a vascular permeability factor. The majority of growth factors transduce their mitogenic signals from cell surface to nucleus where gene expression occurs. Whether these ligands utilize a distinct or a common molecular pathway to exert their biological effects on human endothelial cells remains elusive. We thus studied the expression profile of 884 human genes under the influence of either bFGF or VEGF-A alone in the context of human endothelial cells. A total of ninety-four genes were differentially regulated by more than two folds. The expression patterns of 32 genes are similar between the treatment of either factor alone whereas those of the remaining 62 genes are only regulated by one but not the other factor. Their function in the control of angiogenesis will be discussed and apoptotic signaling in the regulation of angiogenesis is also implicated.

Intravenous sotalol decreases transthoracic cardioversion energy requirement for chronic atrial fibrillation in humans: assessment of the electrophysiological effects by biatrial basket electrodes.

OBJECTIVES: This study was undertaken to assess the effects of sotalol on the transthoracic cardioversion energy requirement for chronic atrial fibrillation (AF) and on the atrial electrograms during AF recorded by two basket electrodes. BACKGROUND: The effects of sotalol infusion on transthoracic electrical cardioversion for chronic atrial fibrillation in humans have not been well investigated. METHODS: We included 18 patients with persistent AF for more than three months. Atrial electrograms were recorded by two basket electrodes positioned in each atrium respectively. Transthoracic cardioversion was performed before and after sotalol 1.5 mg/kg i.v. infusion. RESULTS: In the 14 patients whose AF could be terminated by cardioversion before sotalol infusion, the atrial defibrillation energy was significantly reduced after sotalol infusion (236 +/- 74 jules [J] vs. 186 +/- 77 J; p < 0.01). Atrial fibrillation was refractory to cardioversion in four patients at baseline and was converted to sinus rhythm by cardioversion after sotalol infusion in two of them. We further divided the patients into two groups. Group A consisted of 10 patients in whom the energy requirement was decreased by sotalol while group B consisted of eight patients in whom the energy requirement was not decreased. The mean A-A (atrial local electrogram) intervals during AF were significantly increased after sotalol infusion in both groups, but the increment of A-A interval was significantly larger in group A than it was in group B patients (36 +/- 13 ms vs. 22 +/- 8 ms for the right atrium; 19 +/- 7 ms vs. 9 +/- 7 ms for the left atrium; both p < 0.05). The spatial and temporal dispersions of A-A intervals were not significantly changed after sotalol infusion in both atria in both groups. CONCLUSIONS: Sotalol decreases the atrial defibrillation energy requirement by increasing atrial refractoriness but not by decreasing the dispersion of refractoriness.