Standardized bench test evaluation of coronary stents: Biomechanical characteristics.

OBJECTIVES: The purpose of the study was to develop a standardized and global bench test protocol to evaluate the biomechanical characteristics of the most currently used drug-eluting coronary stents. BACKGROUND: The use of coronary stents has contributed to the reduction of cardiovascular mortality but can be associated with specific complications. Improving the biomechanical matching between the stents and the coronary anatomy may reduce these complications. METHODS: We assessed five commercially available drug-eluting stents: the Absorb, Orsiro, Resolute Onyx, Synergy, and Xience Alpine stents. Following stent deployment at nominal pressure in ambient air, radial elastic recoil and foreshortening were measured. Flexibility (crimped and deployed stents) and longitudinal and radial resistances were evaluated using a mechanical tester. RESULTS: Biomechanical characteristics were significantly different for all tested devices (ANOVA, P < 0.01). The Synergy, Orsiro, and Xience Alpine stents presented the lowest elastic recoil. The Synergy and Resolute Onyx stents were the most flexible devices. The Xience Alpine and Absorb stents had the highest longitudinal and radial resistances. CONCLUSIONS: Drug-eluting coronary stents used in current clinical practice have very different biomechanical characteristics, which should be taken into consideration to select the most appropriate device for each clinical situation.

Study of Nanohydroxyapatite Coatings Prepared by the Electrophoretic Deposition Method at Various Voltage and Time Parameters.

The aim of the work is to compare the properties of nanohydroxyapatite coatings obtained using the electrophoretic deposition method (EDP) at 10 V, 20 V, and 30 V, and with deposit times of 2 and 5 min. The primary sedimentation was used to minimize the risk of the formation of particle agglomerates on the sample surface. Evaluation of the coating was performed by using a Scanning Electron Microscope (SEM), Energy-Dispersive Spectroscopy (EDS), Atomic Force Microscopy (AFM), optical profilometer, drop shape analyzer, and a nanoscratch tester. All of the coatings are homogeneous without any agglomerates. When low voltage (10 V) was used, the coatings were uniform and continuous regardless of the deposition time. The increase in voltage resulted in the formation of cracks in the coatings. The wettability test shows the hydrophilic behavior of the coatings and the mean contact angle values are in the range of 20-37°. The coatings showed excellent adhesion to the substrate. The application of a maximum force of 400 mN did not cause delamination in most coatings. It is concluded that the optimal coating for orthopedic implants (such as hip joint implants, knee joint implants or facial elements) is obtained at 10 V and 5 min because of its homogeneity, and a contact angle that promotes osseointegration and great adhesion to the substrate.

Mechanical Properties and Wear Susceptibility Determined by Nanoindentation Technique of Ti13Nb13Zr Titanium Alloy after "Direct Laser Writing".

Laser treatment has often been applied to rebuild the surface layer of titanium and its alloys destined for long-term implants. Such treatment has always been associated with forming melted and re-solidified thin surface layers. The process parameters of such laser treatment can be different, including the patterning of a surface by so-called direct writing. In this research, pulse laser treatment was performed on the Ti13Nb13Zr alloy surface, with the distance between adjacent laser paths ranging between 20 and 50 µm. The obtained periodic structures were tested to examine the effects of the scan distance on the microstructure using SEM, the roughness and chemical and phase composition using EDS and XRD, and the mechanical properties using the nanoindentation technique. After direct laser writing, the thickness of the melted layers was between 547 and 123 µm, and the surface roughness varied between 1.74 and 0.69 µm. An increase in hardness was observed after laser treatment. The highest hardness, 5.44 GPa, was obtained for the sample modified with a laser beam spacing of 50 µm. The value of the distance has been shown to be important for several properties and related to a complex microstructure of the thin surface layer close to and far from the laser path.

Effects of weaving parameters on the properties of completely biological tissue-engineered vascular grafts.

Tissue-Engineered Vascular Grafts (TEVGs) made of human textiles have been recently introduced and offer remarkable biocompatibility as well as tunable mechanical properties. The approach combines the use of Cell-Assembled extracellular Matrix (CAM) threads, produced by cultured cells in vitro, with weaving, a versatile assembly method that gives fine control over graft properties. Herein, we investigated how production parameters can modify the geometrical and mechanical properties of TEVGs to better match that of native blood vessels in order to provide long-term patency. Our goals were to decrease the mechanical strength and the luminal surface profile of our first generation of woven TEVGs, while maintaining low transmural permeability and good suture retention strength. Different TEVGs were produced by varying CAM sheet strength as well as weaving parameters such as warp count, weft ribbons width, and weft tension. An optimized design reduced the burst pressure by 35%, wall thickness by 38% and increased compliance by 269%. The improved TEVG had properties closer to that of native blood vessels, with a burst pressure of 3492 mmHg, a wall thickness of 0.69 mm, and a compliance of 4.8%/100 mmHg, while keeping excellent suture retention strength (4.7 N) and low transmural permeability (24 mL·min-1·cm-2). Moreover, the new design reduced the luminal surface profile by 48% and utilized 47% less CAM. With a comparable design, the use of decellularized CAM threads, instead of devitalized ones, led to TEVGs with much more permeable walls and higher burst pressure. The next step is to implant this optimized graft in an allogeneic sheep model of arteriovenous shunt to assess its in vivo remodeling and performance. .

Epidemiology of a measles epidemic in Vietnam 2008-2010.

BACKGROUND: Vietnam conducted a measles catch-up supplementary immunization activity (SIA) during 2002-2003 that targeted children 9 months-10 years of age, followed by subnational SIAs targeting persons up to 20 years of age during 2004 and 2007-2008. A measles epidemic began among young adults in October 2008 in the northern region, spread nationwide during early 2009, and continued during 2010. METHODS: We reviewed national epidemiologic and laboratory surveillance data. Measles cases were defined and classified according to World Health Organization recommendations. RESULTS: From October 2008 through January 2010, 7948 confirmed measles cases were reported from 60 of 63 provinces, an incidence of 93 cases per million population. Incidence was 328 cases per million population among children age 1-4 years, 318 cases per million population among infants, and 271 cases per million population among persons aged 20-24 years. Few cases were reported among persons 7-17 or >27 years of age. Median age of cases trended downward over time in all regions. CONCLUSIONS: The 2002-2003 measles SIA protected its targeted age group, but this epidemic was not prevented by follow-up subnational SIAs in selected provinces during 2007-2008. Transmission began among young adults and was sustained among children. The outcome of Vietnam's 2010 SIA targeting children only and change in routine schedule may influence elimination strategies for other countries.

The formulation and implementation of a national helmet law: a case study from Viet Nam.

PROBLEM: Road traffic injuries are a leading cause of death and disability in Viet Nam. In 2008, official data reported 11 243 deaths and 7771 serious injuries on the roads, of which an estimated 60% of fatalities occur in motorcycle riders and passengers. In recognition of this problem, Viet Nam has had partial motorcycle helmet legislation since 1995. However, for a variety of reasons, implementation and enforcement have been limited. APPROACH: On 15 December 2007, Viet Nam's first comprehensive mandatory helmet law came into effect, covering all riders and passengers on all roads nationwide. Penalties increased ten-fold and cohorts of police were mobilized for enforcement. LOCAL SETTING: The Viet Nam national helmet legislation was developed and implemented by the National Traffic Safety Committee. RELEVANT CHANGES: Despite past barriers to enforcement, increased policing in 2008 led to 680 000 infringements being issued for non-helmet wearing. While changes in helmet wearing were not nationally observed, significant increases were documented in selected provinces in the first six months of the law's introduction. In Da Nang, helmet wearing increased from 27 to 99%. In the first three months after the law took effect, surveillance data from 20 urban and rural hospitals, found the risk of road traffic head injuries and deaths decreased by 16% and 18% respectively. LESSONS LEARNT: Political leadership, intensive advanced public education and stringent enforcement have contributed to the successful implementation of the new law. Through continual monitoring of the legislation, loopholes detrimental to the effectiveness of the law have been identified and addressed.

People's initiative to counteract misinformation and marketing practices: the Pembo, Philippines, breastfeeding experience, 2006.

The Philippines is among 42 countries accounting for 90% of under 5-year-old deaths. Only 16% of 4 to 5 month old Filipinos exclusively breastfeed. In 2006, almost $100 million was spent advertising formula in the Philippines. To counter widespread misinformation and improve breastfeeding a peer counseling intervention was developed to target mothers with infants less than 2 months of age who were not exclusively breastfeeding or had difficulty breastfeeding. Participants received 3 peer counseling visits. At baseline and 3 weeks later, 24-hour food recalls for infants were collected. The number of exclusively formula-fed infants decreased seven-fold (P < .001). Mixed-fed infants decreased 37% (P < .001). Overall, of the 148 nonexclusively breastfeeding infants, 69.5% had changed feeding methods after 3 home visits, 76% of whom to exclusive breastfeeding. Community-based peer counseling was associated with a drastic improvement of exclusive breastfeeding practices. This intervention evolved and became sustainable by engaging political figures, cities, and communities throughout the process. In 2 years, the Department of Health, World Health Organization (WHO) program has scaled up to improve health service delivery for 161,612 persons in depressed urban communities in the Philippines.

The Philippines 2004 measles campaign: a success story towards elimination.

Prior to the 2004 Philippines Measles Follow up Elimination Campaign, measles caused an estimated 6000 deaths among Filipino children. After the campaign, cases and deaths decreased by 96.4% and 99.2%, respectively. The Nationwide Rapid Coverage Assessments, with an extensive system of feedback, was the prime factor in reaching the under-immunized areas.

Variability of slot size in orthodontic brackets.

Objective: The accuracy of the information incorporated into brackets is a determining factor for the efficacy of torque applied to teeth. The aim of this study was to compare the dimensions of a bracket's slots with the nominal values announced by the manufacturer. Materials and methods: A total of 730 maxillary right central brackets manufactured by seven companies (Dentsply Gac, American Orthodontics, Rocky Mountain Orthodontics, GC Orthodontics, 3M Unitek, and Dentaurum) were studied. The sample included 0.018 × 0.025 and 0.022 × 0.028 in., metal and ceramic, conventional and self-ligating brackets. Images were obtained with an Olympus BX51 optical microscope. Slot dimensions were measured at the base and at the face on both mesial and distal sides using ImageJ software. Data were analyzed using Wilcoxon, sign tests, two- and three-way ANOVA, and Tukey's tests. Intraclass correlation coefficient was employed to assess the intraobserver and interobserver variability. The threshold for statistical significance was p ≤ .05. Results: Statistical analysis showed that the slot dimensions of 90% to 97% of studied brackets were significantly different from nominal values. In general, slot size was oversized, with a face size larger than the base size. Comparison between mesial and distal sides showed that up to 45% of the brackets were significantly asymmetrical. The manufacturer had a significant effect for base and face widths (p = .0001) and for length (p = .003). Conclusion: This study shows that a large proportion of measured brackets displays dimensional inaccuracies when compared with stated values. Clinically, the slot oversize and the divergence of slot walls cause an increase of wire-slot play, inducing a loss of torque control. Practitioners cannot fully trust the precision of used appliances and should be aware that adjustments could be needed in the finishing stages of the treatment.

Remote imaging of single cell 3D morphology with ultrafast coherent phonons and their resonance harmonics.

Cell morphological analysis has long been used in cell biology and physiology for abnormality identification, early cancer detection, and dynamic change analysis under specific environmental stresses. This work reports on the remote mapping of cell 3D morphology with an in-plane resolution limited by optics and an out-of-plane accuracy down to a tenth of the optical wavelength. For this, GHz coherent acoustic phonons and their resonance harmonics were tracked by means of an ultrafast opto-acoustic technique. After illustrating the measurement accuracy with cell-mimetic polymer films we map the 3D morphology of an entire osteosarcoma cell. The resulting image complies with the image obtained by standard atomic force microscopy, and both reveal very close roughness mean values. In addition, while scanning macrophages and monocytes, we demonstrate an enhanced contrast of thickness mapping by taking advantage of the detection of high-frequency resonance harmonics. Illustrations are given with the remote quantitative imaging of the nucleus thickness gradient of migrating monocyte cells.

Measles and Rubella Global Strategic Plan 2012-2020 midterm review report: Background and summary.

Measles, a vaccine-preventable illness, is one of the most infectious diseases known to man. In 2015, an estimated 134,200 measles deaths occurred globally. Rubella, also vaccine-preventable, is a concern because infection during pregnancy can result in congenital defects in the baby. More than 100,000 babies with congenital rubella syndrome were estimated to have been born globally in 2010. Eradication of both measles and rubella is considered to be feasible, beneficial, and more cost-effective than high-level control. All six World Health Organization (WHO) regions have measles elimination goals by 2020 and two have rubella elimination goals by that year. However, the World Health Assembly has not endorsed a global eradication goal for either disease. In 2012, the Measles and Rubella Initiative published a Global Measles and Rubella Strategic Plan, 2012-2020, referred to hereafter as the Plan, which aimed to achieve measles and rubella elimination in at least five WHO regions by end-2020 through the implementation of five core strategies, with progress evaluated against 2015 milestones. When, by end-2015, none of these milestones had been met, WHO's Strategic Advisory Group of Experts on Immunization (SAGE) recommended a mid-term review of the Plan to evaluate progress toward goals, assess the quality of strategy implementation, and formulate lessons learned. A five-member team reviewed documents and conducted interviews with stakeholders as the basis for the review's conclusions and recommendations. This team concluded that, although significant progress in measles elimination had been made, progress had slowed. It recommended that countries continue to work toward elimination goals with a focus on strengthening ongoing immunization systems. In addition, it concluded that the strategies articulated in the Plan were sound, however full implementation had been impeded by inadequate country ownership and global political will, reflected in inadequate resources. Detailed recommendations for each of the Plan's five strategies as well as the areas of polio transition, governance and resource mobilization are outlined.

Player or referee? Aid effectiveness and the governance of health policy development: Lessons from Viet Nam.

Viet Nam is one of the brightest stars in the constellation of developing countries. Its remarkable achievements in reducing poverty and improving health and education outcomes are well known, and as a result it has enjoyed generous aid programmes. Viet Nam also has a reputation for taking a strong lead in disciplining its donors and pushing for more efficient and effective forms of aid delivery, both at home and internationally. This article discusses how efforts to improve the effectiveness of aid intersect with policy-making processes in the health sector. It presents a quantitative review of health aid flows in Viet Nam and a qualitative analysis of the aid environment using event analysis, participant observation and key informant interviews. The analysis reveals a complex and dynamic web of incentives influencing the implementation of the aid effectiveness agenda in the health sector. There are contradictory forces within the Ministry of Health, within government as a whole, within the donor community and between donors and government. Analytical frameworks drawn from the study of policy networks and governance can help explain these tensions. They suggest that governance of health aid in Viet Nam is characterised by multiple, overlapping 'policy networks' which cut across the traditional donor-government divide. The principles of aid effectiveness make sense for some of these communities, but for others they are irrational and may lead to a loss of influence and resources. However, sustained engagement combined with the building of strategic coalitions can overcome individual and institutional incentives. This article suggests that aid reform efforts should be understood not as a technocratic agenda but as a political process with all the associated tensions, perverse incentives and challenges. Partners thus need to recognise - and find new ways of making sense of - the complexity of forces affecting aid delivery.

Is unimpeded marketing for breast milk substitutes responsible for the decline in breastfeeding in the Philippines? An exploratory survey and focus group analysis.

Infant mortality and morbidity risk is linked to formula usage. The proportion of Filipino infant formula users rose 6% between 2003 and 2008. It is hypothesized this rise resulted from aggressive formula industry marketing. We conducted a household survey between April and December 2006 and focus groups in April-May 2007 in The Philippines to examine the association between mothers' exposure to advertising and other information sources and formula feeding decisions. Sixteen barangays (communities) were randomly selected from three purposively selected disadvantaged rural, urban and mixed municipalities. A total of 345 households had children under 24-months age: 114, 142 and 89 households from the rural, urban and mixed municipalities, respectively. In addition 38 respondents participated in 3 focus groups of 10-15 participants each, from three selected barangays. After adjusting for education and economic indicators logistic regression analysis showed that, children were more likely to be given formula if their mother recalled advertising messages, or a doctor, or mother or relative recommended it. Those using formula were 6.4 (1.8-23.1) times more likely to stop breastfeeding before 12 months. The focus groups described how television advertisements, doctors and medical representatives enticed them to use formula. We conclude that two factors were strongly associated with the decision to formula feed: self-reported advertising exposure, and physicians' recommendations.

Roughness analysis of the cracked surfaces of a face centered cubic alloy.

Intergranular and transgranular fracture surfaces obtained in a face centered cubic alloy are studied using 3D maps reconstructed by scanning electron microscopy stereo imaging. The roughness exponents measured in the intergranular and transgranular surfaces, respectively, zeta = 0.83 +/- 0.05 and zeta = 0.75 +/- 0.05, are in agreement with the universal roughness value of 3D fractures. However, the slightly smaller value related to the transgranular surface could be a consequence of crystallographic transgranular zones disseminated on the surface whose roughness exponent zeta = 0.65 +/- 0.07 is close to the one usually measured on 2D fractures.

Global measles elimination efforts: the significance of measles elimination in the United States.

Lessons learned from the successful end of endemic measles virus transmission (i.e., elimination) in the United States include the critical roles of strong political commitment, a regionwide initiative, adequate funding, and a broad coalition of partners. Implications of measles elimination in the United States for global measles control and regional elimination efforts include demonstration of the high vaccination coverage and, in turn, population immunity needed for elimination; the importance of accurate monitoring of vaccination coverage at local, state, and national levels; a vaccination strategy that includes at least 2 opportunities for measles immunization; and the essential role of integrated epidemiological and laboratory surveillance. The United States, with a population of 288 million, is, to our knowledge, the largest country to have ended endemic measles transmission. This experience provides evidence that sustained interruption of transmission can be achieved in large geographic areas, suggesting the feasibility of global eradication of measles.