Shear bond strength of the ceramic veneer to additively manufactured titanium.

OBJECTIVES: The objective of this in vitro study was to evaluate the shear bond strength between the ceramic veneer and additively manufactured titanium with different surface treatments, and to compare with milled titanium. Also, to characterize the surface and the presence of an α-case layer of additively manufactured and milled titanium. MATERIAL AND METHODS: Sixty additively manufactured titanium grade 23, and 20 milled titanium grade 4 cylindrical specimens were divided into four groups based on surface treatments, air-particle abrasion and grinding. After ceramic veneering half of each group were thermocycled. The bond strength was analyzed using a shear bond strength test. The surfaces were analyzed using interferometry and scanning electron microscopy. RESULTS: The grinding procedure and air-particle abrading pressure had no significant effect on the shear bond strength (p = .264 and p = .344). Thermocycling showed a tendency towards an effect but not significant (p = .052). The group with the highest air-abrading pressure showed the highest surface roughness. No presence of an α-case layer was detected in any of the groups. CONCLUSION: Additively manufactured titanium grade 23 may be veneered with ceramics without prior grinding of the surfaces.

Thrombogenicity of biodegradable metals.

Biodegradable metals offer a promising means to ameliorate many of the long-term risks associated with vascular devices made of conventional biostable stent metals. While numerous biodegradable metal alloys have been developed and characterized in animal models, knowledge of their blood reactivity and thrombogenicity remains unknown. Metal hemocompatibility is particularly valuable because current generation drug-eluting stents pose a significant long-term thrombosis risk. In this study, four pure metals, widely used as degradable base materials (Fe, Zn, Mg, and Mo), and three alloys commonly used in cardiovascular devices [NiTi, CoCr, and stainless steel (SS)] were evaluated. This work examined how each of these metals activate platelets, coagulation factors, and inflammation using in vitro hemocompatibility assays and a clinically relevant ex vivo non-human primate arteriovenous shunt model. Testing found that while all metals promoted a downstream activation of platelets and coagulation in flowing whole blood, platelet and fibrin attachment to Mg was markedly reduced. Additionally, Fe and Mo trended toward higher platelet attachment and contact pathway activation. Overall, the results suggest that Mg may delay clot initiation, but not eliminate clot formation, indicating the importance of understanding thrombosis in Mg alloys that are currently being developed for clinical use as biodegradable stents.

Modelling the impact of extended vaccination strategies on the epidemiology of pertussis.

The aim of this study was to investigate the optimal pertussis booster vaccination strategy for The Netherlands. A realistic age-structured deterministic model was designed. Assuming a steady-state situation and correcting for underreporting, the model was calibrated using notification data from the period 1996-2000. Several sensitivity analyses were performed to explore the impact of different assumptions for parameters surrounded by uncertainty (e.g. duration of protection after natural infection, underreporting factors, and transmission probabilities). The optimal age of an additional booster dose is in the range of 10-15 years, and implementation of this booster dose will reduce both symptomatic and asymptomatic infections, although the incidence of symptomatic infections in older age groups will increase. The impact of the different assumptions used in the model was in general limited. We conclude that over a wide range of assumptions, an additional booster dose can reduce the incidence of pertussis in the population.

Review: What have we learned about the effects of heat stress on the pig industry?

Pig production faces seasonal fluctuations. The low farrowing rate of sows mated in summer, increased carcass fatness of progeny born to the sows mated in summer, and slower growth rate of finisher pigs in summer are three economically important impacts identified in the pig industry. The purpose of this review is to examine advances over the past decade in understanding the mechanisms underlying the three impacts associated with summer conditions, particularly heat stress (HS), and to provide possible amelioration strategies. For impact 1, summer mating results in low farrowing rates mainly caused by the high frequency of early pregnancy disruptions. The contributions of semen DNA damage, poor oocyte quality, local progesterone concentrations, and suboptimal embryonic oestrogen secretion are discussed, as these all may contribute to HS-mediated effects around conception. Despite this, it is still unclear what the underlying mechanisms might be and thus, there is currently a lack of commercially viable solutions. For impact 2, there have been recent advances in the understanding of gestational HS on both the sow and foetus, with gestational HS implicated in decreased foetal muscle fibre number, a greater proportion of lighter piglets, and increased carcass fatness at slaughter. So far, no effective strategies have been developed to mitigate the impacts associated with gestational HS on foetuses. For impact 3, the slowed growth rate of pigs during summer is one reason for the reduced carcass weights in summer. Studies have shown that the reduction in growth rates may be due to more than reductions in feed intake alone, and the impaired intestinal barrier function and inflammatory response may also play a role. In addition, it is consistently reported that HS attenuates fat mobilisation which can potentially exacerbate carcass fatness when carcass weight is increased. Novel feed additives have exhibited the potential to reduce the impacts of HS on intestinal barrier function in grower pigs. Collectively, based on these three impacts, the economic loss associated with HS can be estimated. A review of these impacts is warranted to better align the future research directions with the needs of the pig industry. Ultimately, a better understanding of the underlying mechanisms and continuous investments in developing commercially viable strategies to combat HS will benefit the pig industry.

Heat stress of gilts around farrowing causes oxygen insufficiency in the umbilical cord and reduces piglet survival.

Late gestating sows are susceptible to high ambient temperatures, possibly causing farrowing complications and reducing piglet survival. This experiment aimed to quantify in the days leading up to farrowing the impact of sow heat stress (HS) on farrowing physiology and survival of the piglets. Pregnant primiparous sows (gilts) were allocated to either thermoneutral control (CON, n = 8; constant 20 °C) or cyclical HS conditions (n = 8; 0900 h to 1700 h, 30 °C; 1700 h to 0900 h, 28 °C) from d 110 of gestation until farrowing completion. Gilt respiration rate, skin temperature and rectal temperature were recorded daily, and farrowing duration was quantified by video analyses. Blood samples were collected from the piglet umbilical vein at birth. At 48 h of age, piglet growth was quantified by morphometric analyses. The thermal exposure model induced HS and respiratory alkalosis in the gilts, as indicated by increased respiration rate, rectal temperature, skin temperature (all P < 0.001), plasma cortisol (P = 0.01) and blood pH (P < 0.001). Heat-stressed gilts took longer to start expelling placentae (P = 0.003), although the active farrowing duration was not significantly different between treatments. Stillbirth rates were higher in the HS group (P < 0.001), with surviving piglets at birth having lower umbilical vein partial pressure of oxygen (P = 0.04), oxygen saturation rate (P = 0.03) and tending to have increased lactate concentrations (P = 0.07). At birth, piglet skin meconium staining scores were greater in the HS group (P = 0.022). At 48 h of age, piglets from the HS group had reduced small intestinal length (P = 0.02), reduced jejunal crypt depth (P = 0.02) and lighter absolute brain weight (P = 0.001). In contrast, piglet BW, growth rate, relative organ weight and small intestinal mucosal barrier function did not change between treatments. Collectively, these findings demonstrated gilt HS during late gestation caused farrowing complications and reduced the umbilical oxygen supply to the piglets at parturition, leading to increased risks of piglet stillbirth with implications on impaired neonatal survivability and development.

Association between difference in blood pressure reduction and risk of cardiovascular events in a type 2 diabetes population: A meta-regression analysis.

AIM: Recent US recommendations indicate a target blood pressure (BP) of 130/80mmHg for patients with type 2 diabetes (T2D). Our aim was to characterize the association between risk of cardiovascular events and differences in BP decreases in randomized trials of a T2D population. METHODS: A systematic search was made for randomized clinical trials assessing the effects of antihypertensive treatments in T2D patients on mortality, and fatal and non-fatal cardiovascular events, using a meta-regression technique to explore the influence of BP decreases on treatment effects. RESULTS: A total of 88,503 patients from 44 randomized trials were included. There was no significant association between BP decreases and risk of all-cause or cardiovascular mortality, cardiovascular events or myocardial infarction. However, stroke risk was influenced by BP decreases: compared with no reduction, a 10-mmHg reduction in systolic BP was associated with a relative odds ratio (OR) decrease of 33% (OR: 0.67, 95% CI: 0.54-0.82), and a 5-mmHg diastolic BP reduction was associated with a relative OR decrease of 38% (OR: 0.62, 95% CI: 0.50-0.76). Restricting the analysis to double-blind studies did not change the results for diastolic BP. CONCLUSION: A reduction in BP lowers the risk of stroke, but does not appear to affect the risk of other cardiovascular events in a T2D population.

The effectiveness and safety of dorzolamide 2% in addition to multiple topical antiglaucoma medications.

Dorzolamide is the first commercial topical carbonic anhydrase inhibitor approved by the Food and Drug Administration (FDA) for the treatment of glaucoma. In a prospective, open label, uncontrolled study on 245 glaucoma patients, dorzolamide significantly lowered the intraocular pressure at least 14% when used alone or in combination with one, two, or three other antiglaucoma medications over ten weeks. There were very few adverse reactions to dorzolamide. Dorzolamide is effective and safe when used alone or in combination with other topical antiglaucoma medications for the treatment of glaucoma.

Differential time preferences for money and quality of life.

BACKGROUND: This study provides an empirical investigation into differential time preferences between money and quality of life. Thus far, time preference investigations in health have mostly involved life-years gained and lives saved. However, the quality-adjusted life-year, which is recommended by several bodies, is a multiplicative measure of life duration and quality of life. To our knowledge, our study is the first to follow this approach specifically for quality of life. METHODS: A questionnaire was developed to elicit time preferences for quality of life and for money, and it was distributed to a representative sample of the Dutch population. We also investigated the impact of population characteristics, such as current health state, optimistic/pessimistic future views or gender, on time preferences. RESULTS: We found that discount rates for both money and quality of life decrease with increasing time of delay, with rates of the former being consistently at least two times higher than those of the latter. Similar trends in time preferences were observed across the subgroups, with the exception of the relatively high education subgroup. CONCLUSION: In agreement with the results of other studies, our empirically derived discount rates are higher than the rates featured in national guidelines for health care economic assessment. Our empirical study adds to the evidence for differential discounting, both with regards to money and health, as well as in time.

[Urgent pericardiectomy, 15 cases (author's transl)]. / 15 dringliche Fälle von akuter Perikarditis, behandelt mit Perikardektomie.

UNLABELLED: 15 cases of pericarditis with tamponade operated as emergency cases in Cho Ray Hospital from November 1976 to January 1979 are dealt with. In these 15 cases, 11 were urgently treated with pericardiectomy, 3 cases with pericardiotomy and one case with repeated pericardial punctures. From these latters pericardiectomy had to be performed in one case later because of constrictive pericarditis and evolutive cardiac failure. ETIOLOGY: Pericardial and metastatic tumour 5, suppurative pericarditis 7, Haemopericard after closed chest trauma 1, rheumatic fever 1, tuberculosis 1. RESULTS: 11 patients showed good results, 3 patients died of disseminated lesions of cancer, 1 patient with suppurative pericarditis died a few days after the operation of respiratory insufficiency. A conservative operation seems to be impossible for radically curing the disease and many post-operative complications may occur.

Houseflies are an unlikely reservoir or vector for Helicobacter pylori.

The route of transmission of Helicobacter pylori from individual to individual remains undefined. It has recently been reported that the domestic housefly, Musca domestica, when fed pure cultures of H. pylori, was able to harbor the organism in its midgut for up to 30 h (P. Grubel, S. Hoffman, F. K. Chong, N. A. Barstein, C. Mepani, and D. R. Cave, J. Clin. Microbiol. 35:1300-1303, 1997). Our investigation examined whether houseflies could acquire H. pylori from fresh human feces. Domestic houseflies (40 flies/group) were exposed for 24 h to feces from an H. pylori-positive volunteer, feces from an H. pylori-negative volunteer, or feces from an H. pylori-negative volunteer to which a known amount of viable H. pylori had been added. At various intervals, flies were sacrificed and the midguts were excised, homogenized, and plated in duplicate onto selective horse blood agar plates. All plates were incubated under microaerobic conditions at 37 degreesC for 14 days. Emergent colonies presumptive of H. pylori were picked and tested biochemically to confirm the identity as H. pylori. H. pylori was not recovered from houseflies fed human feces either naturally infected or artificially infected with H. pylori. These results suggest that the domestic housefly is not a vector for transmission or a reservoir for H. pylori infection.