Long-Term Bonding Efficacy of CAD/CAM Hybrid Restorative Materials and Universal Adhesives.

OBJECTIVES: In-office and lab milled prostheses are the staple for indirect restorations. It is therefore critical to determine their long-term bonding durability. METHODS: CAD/ CAM blocks of two classes of restorative materials: 1) a nano-ceramic reinforced polymer matrix (NCPM) and, 2) a polymer-infiltrated ceramic network (PICN) were bonded using four different universal adhesives (UA) and silane systems. A lithium disilicate glassceramic (LDS) was used as a reference. The blocks were bisected and bonded with different UA/resin-cement pairs. Bonded blocks were then cut into 1.0x1.0x12.0 mm bar specimens for microtensile bond testing. Half the bars were subjected to bond strength testing immediately and the other half after aging by 50,000 thermal cycles between 5°C and 55°C. ANOVA and post-hoc tests were used to compare mean bond strength among groups. RESULTS: NCPM presented consistently high bond strength regardless of bonding techniques, while the bond strength of PICN and LDS were lower when bonded with UA relative to traditional silanes. The more hydrophilic UA produced higher bond strengths. DISCUSSION: Glass-ceramics exhibited lower bond strength with UA than the conventional etch-rinse-silane techniques. However, UAs preserved bonding interface in the long-term. SIGNIFICANCE: NCPM displayed superior bond strength relative to PICN and LDS regardless of the type of adhesives and bonding techniques.

Endodontic Access Effect on Full Contour Zirconia and Lithium Disilicate Failure Resistance.

OBJECTIVES: To evaluate the effect of endodontic access on the failure load resistance of both adhesively and conventionally luted, full-contour monolithic yttria-stabilized zirconium dioxide (Y-TZP) and adhesively luted lithium disilicate (LD) crowns cemented on prepared teeth. METHODS AND MATERIALS: Seventy-two human maxillary molars were prepared per respective guidelines for all-ceramic crowns with one group (n=24) restored with LD and the other (n=48) receiving Y-TZP crowns. Preparations were scanned using computer-aided design/computer-aided milling (CAD/CAM) technology, and milled crowns were sintered following manufacturer recommendations. All LD crowns and half (n=24) of the Y-TZP crowns were adhesively cemented, while the remaining Y-TZP specimens were luted using a conventional glass ionomer cement (GIC). One LD group, one Y-TZP adhesive group, and one GIC-luted group (all n=12) then received endodontic access preparations by a board-certified endodontist: the pulp chambers were restored with a dual-cure, two-step, self-etch adhesive and a dual-cure resin composite core material. The access preparations were restored using a nano-hybrid resin composite after appropriate ceramic margin surface preparation. After 24 hours, all specimens were loaded axially until failure; mean failure loads were analyzed using Mann-Whitney U test (α=0.05). RESULTS: Endodontic access did not significantly reduce the failure load of adhesively luted LD or Y-TZP crowns, but Y-TZP crowns with GIC cementation demonstrated significantly less failure load. CONCLUSIONS: These initial findings suggest that endodontic access preparation may not significantly affect failure load resistance of adhesively luted Y-TZP and LD crowns. Definitive recommendations cannot be proposed until fatigue testing and coronal seal evaluations have been accomplished.

Microplastics in beluga whales (Delphinapterus leucas) from the Eastern Beaufort Sea.

Microplastics (MPs, particles <5 mm) represent an emerging global environmental concern, having been detected in multiple aquatic species. However, very little is known about the presence of MPs in higher trophic level species, including cetaceans. We worked with community based monitors and Inuvialuit hunters from Tuktoyaktuk (Northwest Territories, Canada) to sample seven beluga whales (Delphinapterus leucas) in 2017 and 2018. Microplastics were detected in the gastrointestinal tracts in every whale. We estimate that each whale contained 18 to 147 MPs in their GI tract (average of 97 ±â€¯42 per individual). FTIR-spectroscopy revealed over eight plastic polymer types, with nearly half being polyester. Fibres made up 49% of MPs. The diversity of MP shapes and polymeric identities in beluga points to a complex source scenario, and ultimately raises questions regarding the significance and long-term exposure of this pollutant in this ecologically and culturally valuable species.

An osmosensing signal transduction pathway in yeast.

Yeast genes were isolated that are required for restoring the osmotic gradient across the cell membrane in response to increased external osmolarity. Two of these genes, HOG1 and PBS2, encode members of the mitogen-activated protein kinase (MAP kinase) and MAP kinase kinase gene families, respectively. MAP kinases are activated by extracellular ligands such as growth factors and function as intermediate kinases in protein phosphorylation cascades. A rapid, PBS2-dependent tyrosine phosphorylation of HOG1 protein occurred in response to increases in extracellular osmolarity. These data define a signal transduction pathway that is activated by changes in the osmolarity of the extracellular environment.

Factors associated with the adoption of a smoking ban in Quebec households.

The home represents an important source of exposure to environmental tobacco smoke for non-smokers, including children, who live with smokers. Our goal is to identify the sociodemographic factors associated with the adoption of smoking bans in "smoker households" in Quebec. Selected associations are compared with three other Canadian provinces (Ontario, British Columbia and Nova Scotia). This is a cross-sectional study involving 2648 respondents. Logistic regression analysis is employed. Few smoker households in Quebec (21%) have a ban on smoking; the presence of a non-smoker is strongly linked to the existence of such a ban; the presence of a child under the age of 6 is less strongly associated with the adoption of a ban in Quebec than in the other provinces, and the presence of an adolescent shows no association whatsoever. In addition to the child health benefits of household smoking bans, greater emphasis should be placed on the impact that such bans can have on children's future smoking behaviour. One option from a health promotion standpoint might be to organize a campaign aimed at non-smokers who live with smokers, in order to urge them to be less tolerant of environmental tobacco smoke.

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.

Host inflammatory response profiling in preeclampsia using an in vitro whole blood stimulation model.

The pathophysiology of preeclampsia (PET) implicates an inflammatory dysfunction. This study profiled this host response by challenging whole blood with lipopolysaccharide. Multiplex immunoassays determined interleukin (IL)-1beta, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12(p70), IL-13, IL-17, granulocyte/granulocyte macrophage-colony stimulating factors (G-CSF/GM-SCF), interferon(IFN)-gamma, monocyte chemotactic protein (MCP)-1, macrophage inflammatory protein-1beta and tumor necrosis factor (TNF)-alpha levels. Secretory capacity was expressed in pg/million white cells or monocytes (+/-SEM). PET featured significantly higher IL-1beta, IL-2, IL-10, IL-13, G-CSF, IFN-gamma, MCP-1 and TNF-alpha monocyte secretory capacities (p < 0.05). The PET group exhibited an inflammatory hyper-responsiveness (p < 0.01) which was poorly described by the traditional Th1:Th2 dichotomy.

Linear Coefficient of Thermal Expansion Evaluation of Glass Ionomer and Resin-Modified Glass Ionomer Restorative Materials.

OBJECTIVE: The purpose of this evaluation was to evaluate the linear coefficient of thermal expansion (LCTE) of 12 conventional glass ionomer (GIC) and four resin-modified glass ionomer (RMGI) restorative materials. METHODS: GIC and RMGI specimens (2 mm × 5 mm × 5 mm) were fabricated (n=12) following manufacturer instructions and were placed in 0.2M phosphate-buffered saline and stored at 37°C and 98% humidity for one week. Specimens had LCTE determined with a thermomechanical analysis (TMA) unit using a 15°C-50°C heating cycle as well as a 50°C-15°C cooling cycle at a 5°C/min rate, using a 3-mm ball-point probe under 0.02 N probe pressure with all specimens kept saturated with PBS using a specially designed quartz container. Each specimen was tested three times, with the mean representing the specimen LCTE. Mean results between specimen heating and cooling were compared with paired Wilcoxon sign rank test, while results between materials were compared with Kruskal-Wallis/Dunn's ( α=0.05). RESULTS: GIC LCTE ranged from approximately 5°C to 20°C ppm °K-1, while the RMGI LCTE ranged from approximately 25°C to 47°C ppm °K-1. With some exception, the LCTE during cooling displayed a greater trend. SIGNIFICANCE: Under moisture conditions similar to the oral cavity, GIC materials overall had LCTE values closer to that reported for tooth structure. RMGI materials displayed higher values, which was thought to be related to the amount of resin in the matrix. A generally greater LCTE trend with cooling for all materials was noted, but the small magnitude of the difference is presently thought to be of minor clinical significance.

Discovery and spectroscopy of the young jovian planet 51 Eri b with the Gemini Planet Imager.

Directly detecting thermal emission from young extrasolar planets allows measurement of their atmospheric compositions and luminosities, which are influenced by their formation mechanisms. Using the Gemini Planet Imager, we discovered a planet orbiting the ~20-million-year-old star 51 Eridani at a projected separation of 13 astronomical units. Near-infrared observations show a spectrum with strong methane and water-vapor absorption. Modeling of the spectra and photometry yields a luminosity (normalized by the luminosity of the Sun) of 1.6 to 4.0 × 10(-6) and an effective temperature of 600 to 750 kelvin. For this age and luminosity, "hot-start" formation models indicate a mass twice that of Jupiter. This planet also has a sufficiently low luminosity to be consistent with the "cold-start" core-accretion process that may have formed Jupiter.

Filtration capture and immunoelectrochemical detection for rapid assay of Escherichia coli O157:H7.

A new approach for rapid assay of bacteria in liquid samples is described. Cells were labeled by incubation with an enzyme-antibody conjugate and captured by filtration of the sample/conjugate mixture through a 0.2 microm filter. The enzyme-labeled cells were detected by placing the filter on the surface of an electrode, incubating with enzyme substrate, and measuring the current produced by oxidation of the electroactive enzyme product. Assay time was 25 min and a detection limit of approximately 5000 cells/ml was obtained for E. coli O157:H7. Background current due to non-specific binding of conjugate to the filter was the primary factor controlling the detection limit, and fewer than 50 cells could be detected when very small sample volumes (10 microl) were used to minimize background current.

Enzyme-linked immunomagnetic electrochemical detection of Salmonella typhimurium.

There is a need for rapid methods to detect pathogenic bacteria in food products as alternatives to the current laborious and time-consuming culture procedures. We report a microbial detection technique that combines the selectivity of antibody-coated superparamagnetic beads with the rapidity and sensitivity of electrochemical detection in a format termed enzyme-linked immunomagnetic electrochemistry. In it, Salmonella typhimurium were sandwiched between antibody-coated magnetic beads and an enzyme-conjugated antibody. With the aid of a magnet, the beads (with or without bound bacteria) were localized onto the surface of disposable graphite ink electrodes in a multi-well plate format. Enzyme substrate was added and conversion of substrate to an electroactive product was measured using electrochemical detection. The electrochemical response was directly proportional to the number of captured bacteria. Using this technique, a minimum detectable level of 8 x 10(3) cells/ml of Salmonella typhimurium in buffer was achieved in ca. 80 min.

The effect of excessive ethanol ingestion on sleep in severe chronic obstructive pulmonary disease.

The effect of a moderately intoxicating dose of ethanol on sleep was evaluated in five patients with severe emphysematous chronic obstructive pulmonary disease (COPD) (mean FEV1 0.83 L, PaO2 75 mm Hg). Mean serum ethanol before sleep was 129 mg/dl. With alcohol, total sleep time per night decreased from a mean of 293 to 238 min. Relative sleep time per stage also changed; NREM time increased, and REM time decreased greater than 50%. Alcohol caused significant O2 desaturation; group mean sleep arterial oxygen saturation (SaO2) decreased from 90.6 to 87.7% with alcohol. Although the decrease in SaO2 was not uniform across all sleep stages, no individual sleep stage accounted for the desaturation. The fall in SaO2 with alcohol was not explained by increasing apneas or hypopneas. Mean heart rate increased significantly from 71.8 to 77.1 with alcohol, with premature ventricular contractions increasing in two subjects. Excessive alcohol ingestion in severe COPD alters total sleep time and stage distribution, decreases SaO2 without significant change in apneas, and increases heart rate. Prior to sleep, patients with severe COPD should strictly limit ingestion of alcohol.

Economies of scale, physician volume for urology patients, and DRG prospective hospital payment system.

Diagnosis Related Group (DRG) hospital payment has begun to squeeze hospitals financially and is likely to do so in the future. This study analyzed the relationship between the volume of urologic procedures by an individual urologist, hospital costs per patient, and outcome. We used a three-year DRG database of urology patients (N = 2,980) at an academic medical center to analyze these. Low-volume urologists (arbitrarily defined by us) had higher hospital costs per patient, financial losses versus profits under DRGs, and a poorer outcome when compared with high-volume urologists. Pearson correlation showed a positive relationship between cost per patient and physician volume for nonemergency patients (-0.129, p less than 0.0001) and emergency patients (-0.368, p less than 0.0001). This may have been explained (in part) by a greater severity of illness for patients of low-volume urologists. These findings suggest, however, that the volume of urologic procedures per urologist may be related to hospital resource consumption. The health care financing environment of the future should provide substantial interest in this finding for those involved in the consumption of urologic services.

Rhythms and responses.

Rhythms are fundamental to behavior, but the control mechanism for timed responses is not known. Many theorists have assumed that there is a central clock coordinating behavior in all sensory modalities and response modes. We tested this hypothesis using a rhythmic tapping task in which university undergraduates first attempted to synchronize responses with brief auditory, tactile, or visual stimuli and then continued to tap at the same rate on their own. Performance was most variable with visual stimuli and least variable with auditory stimuli. The detailed results suggest that performances are not based on a common clock, but, rather, different strategies are employed when the task is presented in different modalities. We reject the hypothesis of a single timing mechanism as controlling behavior and, in doing so, question the validity of information processing models that are formulated without regard to temporal relations among their conjectured processes.

Filtration capture immunoassay for bacteria: optimization and potential for urinalysis.

A novel assay utilizing immuno-labeling, filtration, and electrochemistry for the rapid detection of bacteria has been optimized for the detection of Escherichia coli O157:H7. Bacteria were specifically labeled with alkaline phosphatase conjugated polyclonal antibodies and captured on a polycarbonate track-etched membrane filter (0.2 microm pore size). The filter was then placed directly against a glassy carbon electrode, incubated with enzyme substrate, and the product detected by square wave voltammetry. The high speed and capture efficiency of membrane filtration and inherent sensitivity of electrochemical detection produced a 25-min assay with a detection limit of 5 x 10(3) E. coli O157:H7 per ml using a filtration volume of 100 microl (i.e. 500 cells filtered). The labeling, filtration, and electrochemical steps were optimized, and the assay performance using electrochemical and colorimetric detection methods was compared. The assay was used to detect E. coli O157:H7 that was spiked into filter-sterilized urine at clinically relevant concentrations.

Cocaine self-administration in monkeys by chewing and smoking.

Two rhesus monkeys self-administered cocaine hydrochloride in a gum base vehicle on a fixed ratio 10 schedule with performance characterized by frequent pauses and increased intertrial interval responding. Three other monkeys self-administered cocaine base in lettuce cigarette vehicles in smoking performance marked by shortened puff durations. Urinary benzoyl ecgnoine levels correlated with amount of cocaine chewed or smoked. Monkeys did not prefer cocaine gum in choice tests with plain or procaine gum, but did significantly prefer cocaine cigarettes to plain cigarettes. These preliminary results emphasize the importance of route of administration in determining reinforcement efficacy of human coca use and suggest animal models for their further experimental analysis.

Hospital readmissions, otolaryngology, and the diagnosis related group hospital payment system.

An analysis of otolaryngologic patients requiring readmission was conducted at our institution during a 4-year period to determine the number of readmissions per patient and the time between discharge and hospital readmission. Readmitted otolaryngologic patients were found to have had greater hospital resource utilization, financial risk under diagnosis-related group payment, and mortality, compared with those patients not readmitted to our facility. For patients readmitted to otolaryngologic services (21.2% of total otolaryngologic patients), 20.4% of the readmissions occurred within 30 days of hospital discharge. Of these, 39.3% required one hospital readmission, 16.3% required two readmissions, and 46.4% of the patients called for three or more hospital admissions. Clinical factors were identified that resulted in a greater incidence of otolaryngologic readmission. Otolaryngologic patients readmitted to other clinical services were also studied. This analysis loads to the conclusion that inequities exist within the diagnosis related group hospital payment system vis-à-vis otolaryngologic readmissions. The results of these data also demonstrate leverage points in which we will be able to focus outpatient services for otolaryngologic patients requiring readmission and potentially decrease inpatient hospital expenditures in the days ahead.