Magnesium alloys have attracted great interest for medical applications due to their unique biodegradable capability and desirable mechanical properties. When designed for medical applications, these ...alloys must have suitable degradation properties, i.e., their degradation rate should not exceed the rate at which the degradation products can be excreted from the body. Cellular responses and tissue integration around the Mg-based implants are critical for clinical success. Four magnesium–zinc–strontium (ZSr41) alloys were developed in this study. The degradation properties of the ZSr41 alloys and their cytocompatibility were studied using an in vitro human embryonic stem cell (hESC) model due to the greater sensitivity of hESCs to known toxicants which allows to potentially detect toxicological effects of new biomaterials at an early stage. Four distinct ZSr41 alloys with 4 wt% zinc and a series of strontium compositions (0.15, 0.5, 1, and 1.5 wt% Sr) were produced through metallurgical processing. Their degradation was characterized by measuring total mass loss of samples and pH change in the cell culture media. The concentration of Mg ions released from ZSr41 alloy into the cell culture media was analyzed using inductively coupled plasma atomic emission spectroscopy. Surface microstructure and composition before and after culturing with hESCs were characterized using field emission scanning electron microscopy and energy dispersive X-ray spectroscopy. Pure Mg was used as a control during cell culture studies. Results indicated that the Mg–Zn–Sr alloy with 0.15 wt% Sr provided slower degradation and improved cytocompatibility as compared with pure Mg control.
This month in the Magnet® Perspectives column, Pamela F. Cipriano, PhD, RN, NEA-BC, FAAAN, new President of the American Nurses Association, discusses her priorities for the future and partnerships ...that are being forged to support nursing.
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In 2010, the Patient Protection and Affordable Care Act (ACA, otherwise known as Obamacare) created a blueprint for a potential sea change that's not well understood by many Americans. The ACA's most ...visible impacts are the more than 20 million people now covered with health insurance and the shifting of payments to reward quality rather than quantity of care. Mandated in the ACA, the strategy embraces the goals of the Institute for Healthcare Improvement's Triple Aim: better experience of care that's accessible, reliable, and safer; healthier people and communities, which addresses the behavioral, social, and environmental determinants of health; and more affordable care through lower costs. Nurses are very familiar with the priorities that focus on safer care delivery without harm, patient and family engagement in care, and effective communication and increased care coordination.
The hydrothermal synthesis of nano-faujasite has been successfully performed and the effects of some crystallization parameters were investigated, along with the use of this material as a heavy-metal ...ion adsorbent. X-ray diffraction patterns have shown that the structure of the nano-faujasite is strongly dependent on both the crystallization time and the alkalinity of the synthesis medium. According to N
physisorption, X-ray fluorescence, SEM/EDS, and solid state
Si and
Al NMR data, the produced nano-faujasite consists of a solid with low molar Si/Al ratio (1.7), with high availability of ion exchange sites and high surface area/small particle size, allowing easy diffusion of metal ions to adsorbent active sites. As a consequence, an excellent performance on removal of Cd
, Zn
and Cu
ions was found for this solid. The adsorption capacity followed the order Cd
(133 mg·g
) > Zn
(115 mg·g
) > Cu
(99 mg·g
), which agrees with the order of increasing absolute values of the hydration energy of the metal ions. Kinetic studies and adsorption isotherms showed that the metal ion removal takes place by ion exchange on the monolayer surface of the nano-faujasite. The electrochemical recovery of copper in metallic form exhibited an efficiency of 80.2% after 120 min, which suggests that this process can be adequately implemented for full-scale metal removal.
Biochar and ashes derived from coffee husk were used as heterogeneous catalysts in the synthesis of biodiesel through a transesterification reaction. The catalysts were obtained from the ...carbonization, activation, and combustion of raw coffee husks. Their properties were characterized by solid-state 13C and 31P nuclear magnetic resonance (NMR) spectroscopies and X-ray diffraction, among other techniques. The results evidenced the presence of different inorganic compounds (mostly K- and Ca-containing phases) mixed with the turbostratic structure (in the case of the biochar samples). A biodiesel conversion of 66% (evaluated by 1H NMR analysis of the liquid reaction products) was found for the biochar sample prepared at 700 °C; the activated biochar catalyst prepared at the same temperature showed a higher biodiesel conversion (74%), which can be attributed to its superior specific surface area. The best catalytic efficiency (biodiesel conversion of 93%) was observed for the coffee husk ashes, which is consistent with the higher contents of Ca and K salts in the ashes in comparison with the biochar samples. Reuse tests conducted with the ashes samples showed an efficiency reduction after the second cycle (from around 90% in the first two cycles to 8% in the third cycle), due to the partial removal of active phases (mostly K-containing salts) within the reaction medium. The presented results show that coffee husks are a cheap and environmentally viable source for the production of materials of interest in heterogeneous catalysis, with no need for chemical modification to achieve good efficiency.
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A new biodegradable magnesium–zinc–strontium (Mg–Zn–Sr) alloy was developed and studied for medical implant applications. This first study investigated the alloy processing (casting, rolling, and ...heat treatment), microstructures, mechanical properties, and degradation properties in simulated body fluid (SBF). Aging treatment of the ZSr41 alloy at 175°C for 8h improved the mechanical properties when compared to those of the as-cast alloy. Specifically, the aged ZSr41 alloy had an ultimate tensile strength of 270MPa, Vickers hardness of 71.5HV, and elongation at failure of 12.8%. The mechanical properties of the ZSr41 alloy were superior as compared with those of pure magnesium and met the requirements for load-bearing medical implants. Furthermore, the immersion of the ZSr41 alloy in SBF showed a degradation mode that progressed cyclically, alternating between pitting and localized corrosion. The steady-state average degradation rate of the aged ZSr41 alloy in SBF was 0.96g/(m2·hr), while the pH of SBF immersion solution increased. The corrosion current density of the ZSr41 alloy in SBF solution was 0.41mA/mm2, which was much lower than 1.67mA/mm2 for pure Mg under the same conditions. In summary, compared to pure Mg, the mechanical properties of the new ZSr41 alloy improved while the degradation rate decreased due to the addition of Zn and Sr alloying elements and specific processing conditions. The superior mechanical properties and corrosion resistance of the new ZSr41 alloy make it a promising alloy for next-generation implant applications.
•Developed a new biodegradable magnesium–zinc–strontium (Mg–Zn–Sr) alloy for medical implant applications•Reported Mg–Zn–Sr alloy processing and microstructure characterization•Improved mechanical properties of Mg alloy after aging treatment•Improved degradation properties of Mg alloy in simulated body fluid
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•We analise the role played by the aging of aloe vera on its drag reduction property.•We use 1H NMR to indicate the compositions of our different kinds of leaves.•We use two kinds of apparatus to ...take into account the DR ability of aloe vera.•Samples richer in complex polysaccharides are more efficient.
Polymeric drag reducers have been developed over many years due to the great number of practical applications. In all of them, the molecular stability is an essential requirement. Usually, polymers break down under turbulent flows, which causes a decrease in their efficiency as drag reducers. Besides that, some specific applications, in agro and biomedical fields, impose a specific requirement that must be fulfilled, which is the use of non-toxic materials. A suitable stable material that is elected to accomplish this necessity is the mucilage of aloe vera, which is a bio-polymer that can be used as an alternative to the synthetic ones. Here, we investigate the role played by the aging of aloe vera on its capacity to reduce drag. The results obtained by 1H nuclear magnetic resonance indicate that the compositions of young and mature leaves of aloe vera are different and such a difference plays an important role on their efficiency as drag reducers. Tests were performed to analyse the drag reduction in a rotating apparatus and in a pipeline system and the efficiencies of leaves of different ages were compared to their composition. The main conclusion of these experiments is that the young mucilage samples, which are richer in complex polysaccharides and exhibit lower acid contents, are more efficient drag reducers.
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The objective of this study was to investigate the adhesion and morphology of bone marrow derived stromal cells (BMSCs) on bulk titanium (Ti) substrates with precisely-patterned surfaces consisting ...of groove-based gratings with groove widths ranging from 50 micro m down to 0.5 micro m (500 nm). Although it is well known that certain surface patterning enhances osteoblast (bone-forming cell) functions, past studies on cell-pattern interactions reported in the literature have heavily relied on surface patterning on materials with limited clinical relevance for orthopedic applications, such as polymeric substrates. The clinical need for improving osseointegration and juxtaposed bone formation around load-bearing Ti implants motivated this in vitro study. BMSCs were selected as model cells due to their important role in bone regeneration. The results showed significantly greater BMSC adhesion density and more favorable cell morphology on sub-micropatterned gratings when compared with larger micropatterned gratings and non-patterned control surfaces after both 24 hr and 72 hr cultures. We observed increasing cellular alignment and elongation with decreasing feature size. We also identified two distinctive cellular morphologies: Type I-Attached and spread cells that elongated along the pattern axes; and Type II-Superficially adhered round cells. Sub-micropatterned gratings demonstrated significantly greater Type I cell density than the non-patterned control, and lower Type II cell density than the larger micropatterned gratings. Collectively, these results suggest potential for rationally designing nano-scale surface topography on Ti implants to improve osseointegration.
Care coordination and transitional care services are strategically important for achieving the priorities of better care, better health, and reduced costs embodied in the National Strategy for ...Quality Improvement in Health Care (National Quality Strategy NQS). Some of the most vulnerable times in a person’s care occur with changes in condition as well as movement within and between settings of care. The American Academy of Nursing (AAN) believes it is essential to facilitate the coordination of care and transitions by using health information technology (HIT) to collect, share, and analyze data that communicate patient-centered information among patients, families, and care providers across communities. HIT makes information accessible, actionable, timely, customizable, and portable. Rapid access to information also creates efficiencies in care by eliminating redundancies and illuminating health history and prior care. The adoption of electronic health records (EHRs) and information systems can enable care coordination to be more effective but only when a number of essential elements are addressed to reflect the team-based nature of care coordination as well as a focus on the individual’s needs and preferences. To that end, the AAN offers a set of recommendations to guide the development of the infrastructure, standards, content, and measures for electronically enabled care coordination and transitions in care as well as research needed to build the evidence base to assess outcomes of the associated interventions.
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