Characterization of damage modes in dental ceramic bilayer structures

Results of contact tests using spherical indenters on flat ceramic coating layers bonded to compliant substrates are reported for selected dental ceramics. Critical loads to produce various damage modes, cone cracking, and quasiplasticity at the top surfaces and radial cracking at the lower (inner) surfaces are measured as a function of ceramic-layer thickness. It is proposed that these damage modes, especially radial cracking, are directly relevant to the failure of all-ceramic dental crowns. The critical load data are analyzed with the use of explicit fracture-mechanics relations, expressible in terms of routinely measurable material parameters (elastic modulus, strength, toughness, hardness) and essential geometrical variables (layer thickness, contact radius). The utility of such analyses in the design of ceramic/substrate bilayer systems for optimal resistance to lifetime-threatening damage is discussed.     

The effects of maternal hypercapnia on foetal oxygenation and uterine blood flow in the pig.

1. The purpose of this investigation was to determine the effects of maternal hyperoxaemia and hypercapnia on the uterine vascular bed and foetal oxygenation in the large white sow at 80-90 days gestation. 2. When maternal hyperoxaemia was induced with 100% oxygen, there was a highly significant rise in the maternal arterial oxygen tension, but no other significant blood gas or vascular changes were observed. 3. When mild maternal hypercapnia was superimposed on maternal hyperoxaemia (oxygen plus 6% carbon dioxide), the oxygen tension and saturation of both the maternal uterine venous and foetal umbilical venous bloods were found when severe hypercapnia was induced (oxygen plus 50% carbon dioxide) but in this case all blood samples showed dramatic changes in PCO2 and pH. These changes were accompanied by an increase in the systemic blood pressure and uterine blood flow, and a decrease in uterine vascular resistance. 4. When mild hypercapnia was induced without hyperoxaemia (air plus 5% carbon dioxide) significant increases were recorded in the oxygen tension and saturation of uterine venous and foetal umbilical venous bloods. Systemic and uterine vascular resistance fell. 5. It was concluded that the increased foetal oxygen tension during maternal hypercapnia was the result of the increased uterine blood flow and greater mass delivery of oxygen to the placenta, so that once the oxygen requirements of the placental tissues themselves were exceeded there would be an increased oxygen gradient at the site of gas exchange. 6. Carbon dioxide concentration in arterial blood plays an important role in determining blood flow through the pregnant uterus in the sow.     

Elevated neutrophil to lymphocyte ratio is associated with poor long-term survival and graft failure after lung transplantation

PurposeWe aimed to assess the prognostic value of Neutrophil to Lymphocyte Ratio (NLR) on long-term outcomes and graft dysfunction after lung transplantation.MethodsWe retrospectively reviewed all patients receiving a lung transplant at our institution from 2011 to 2014. The primary exposure was elevated NLR at the time of transplant, defined by NLR>4. The primary outcomes were graft failure and three-year all-cause mortality. Multivariate logistic regression and Kaplan-Meier survival analysis were used to analyze outcomes.Results95 patients were included. 40 patients (42%) had an elevated NLR. Elevated NLR was associated with graft failure (OR: 4.7 [1.2–18.8], p = 0.02), and three-year mortality (OR: 5.4 [1.3–23.2], p = 0.03) on multivariate logistic regression. Patients with elevated NLR demonstrated significantly lower survival on Kaplan-Meier analysis (50% versus 74%, p = 0.02). The c-statistic for our multivariate model was 0.91.ConclusionElevated neutrophil to lymphocyte ratio is associated with poor long-term survival and graft failure after lung transplantation.     

New non-cocaine-containing topical anesthetics compared with tetracaine-adrenaline-cocaine during repair of lacerations

OBJECTIVE: To compare the effectiveness of three new topical anesthetics that do not contain cocaine (prilocaine-phenylephrine, tetracaine-phenylephrine [tetraphen], and tetracaine-lidocaine-phenylephrine) to that of tetracaine-adrenaline-cocaine (TAC) during laceration repair in children. DESIGN: Prospective, randomized, double-blind clinical trial. SETTING: The emergency department of an urban children's hospital. PARTICIPANTS: Children 1 year of age or older with a laceration /= 5 years of age using a visual analogue scale (VAS). Suture technicians, research assistants, and parents also scored pain using a seven-point Likert scale. In addition, suture technicians completed an anesthetic effectiveness scale. RESULTS: There was consistently no difference demonstrated between the effectiveness of tetraphen and that of TAC for each outcome measure of each observer group. A statistically significant difference was seen among anesthetics when comparing VAS and Likert scale scores of suture technicians and Likert scale scores of research assistants. Based on post hoc analyses, these statistically significant differences were between TAC and prilocaine-phenylephrine (suture technician VAS and Likert scale) and between TAC and tetracaine-lidocaine-phenyl-ephrine (suture technician Likert scale), but not between TAC and tetraphen. When power analyses were performed using alpha = 0.05 and beta = 0.20, it was possible to detect a difference of 1.2 VAS units for each of the observer groups. Based on anesthetic effectiveness scale scores, the three new topical preparations collectively performed significantly better on the face and scalp than on the extremities (relative risk = 1.83; 95% confidence interval 1.20 < relative risk < 2.79). CONCLUSION: This study demonstrated the effectiveness and safety of three new non-cocaine-containing topical anesthetics. Consistently, there was no statistical difference demonstrated between the effectiveness of tetraphen and that of TAC for each outcome measure of each observer group. Tetraphen offers an effective alternative to TAC during laceration repair in children.     

Quantitative evaluation of liver-specific promoters from retroviral vectors after in vivo transduction of hepatocytes

Hepatic gene therapy could be used to treat a number of inherited blood diseases such as hemophilia or thrombophilia. Although liver-directed retroviral transduction can result in long-term gene expression in vivo, the low level of protein production has limited its clinical application. We reasoned that the insertion of liver-specific promoters into retroviral vectors would increase gene expression in vivo. The 347- bp human alpha 1-antitrypsin (hAAT), the 810-bp murine albumin (mAIb), the 490-bp rat phosphoenolpyruvate carboxykinase (rPECK), and the 596- bp rat liver fatty acid binding protein promoters were inserted into a Moloney murine leukemia retroviral backbone containing the hAAT reporter gene. Vectors that produced appropriately sized RNA and hAAT protein in vitro were tested in vivo by transducing regenerating rat livers. Long-term serum expression of the hAAT reporter gene was normalized to retroviral transduction efficiency as determined by using a polymerase chain reaction-based assay of genomic DNA from transduced rat livers. The hAAT, mAIb, and rPEPCK promoters were, respectively, 35- , 8-, and 0.02-fold as strong as the previously studied constitutive Pol-II promoter. We conclude that the hAAT promoter resulted in the highest expression from a retroviral vector and may result in therapeutically significant expression of other clinically significant blood proteins.     

Neonatal cause-of-death estimates for the early and late neonatal periods for 194 countries: 2000–2013

ObjectiveTo estimate cause-of-death distributions in the early (0–6 days of age) and late (7–27 days of age) neonatal periods, for 194 countries between 2000 and 2013.MethodsFor 65 countries with high-quality vital registration, we used each country’s observed early and late neonatal proportional cause distributions. For the remaining 129 countries, we used multinomial logistic models to estimate these distributions. For countries with low child mortality we used vital registration data as inputs and for countries with high child mortality we used neonatal cause-of-death distribution data from studies in similar settings. We applied cause-specific proportions to neonatal death estimates from the United Nations Inter-agency Group for Child Mortality Estimation, by country and year, to estimate cause-specific risks and numbers of deaths.FindingsOver time, neonatal deaths decreased for most causes. Of the 2.8 million neonatal deaths in 2013, 0.99 million deaths (uncertainty range: 0.70–1.31) were estimated to be caused by preterm birth complications, 0.64 million (uncertainty range: 0.46–0.84) by intrapartum complications and 0.43 million (uncertainty range: 0.22–0.66) by sepsis and other severe infections. Preterm birth (40.8%) and intrapartum complications (27.0%) accounted for most early neonatal deaths while infections caused nearly half of late neonatal deaths. Preterm birth complications were the leading cause of death in all regions of the world.ConclusionThe neonatal cause-of-death distribution differs between the early and late periods and varies with neonatal mortality rate level. To reduce neonatal deaths, effective interventions to address these causes must be incorporated into policy decisions.