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1.
Sci Rep ; 11(1): 9610, 2021 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-33953260

RESUMO

We demonstrated the design of pre-additive manufacturing microalloying elements in tuning the microstructure of iron (Fe)-based alloys for their tunable mechanical properties. We tailored the microalloying stoichiometry of the feedstock to control the grain sizes of the metallic alloy systems. Two specific microalloying stoichiometries were reported, namely biodegradable iron powder with 99.5% purity (BDFe) and that with 98.5% (BDFe-Mo). Compared with the BDFe, the BDFe-Mo powder was found to have lower coefficient of thermal expansion (CTE) value and better oxidation resistance during consecutive heating and cooling cycles. The selective laser melting (SLM)-built BDFe-Mo exhibited high ultimate tensile strength (UTS) of 1200 MPa and fair elongation of 13.5%, while the SLM-built BDFe alloy revealed a much lower UTS of 495 MPa and a relatively better elongation of 17.5%, indicating the strength enhancement compared with the other biodegradable systems. Such an enhanced mechanical behavior in the BDFe-Mo was assigned to the dominant mechanism of ferrite grain refinement coupled with precipitate strengthening. Our findings suggest the tunability of outstanding strength-ductility combination by tailoring the pre-additive manufacturing microalloying elements with their proper concentrations.

2.
Int J Mol Sci ; 21(20)2020 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-33050160

RESUMO

In this study, we optimized the geometry and composition of additive-manufactured pedicle screws. Metal powders of titanium-aluminum-vanadium (Ti-6Al-4V) were mixed with reactive glass-ceramic biomaterials of bioactive glass (BG) powders. To optimize the geometry of pedicle screws, we applied a novel numerical approach to proposing the optimal shape of the healing chamber to promote biological healing. We examined the geometry and composition effects of pedicle screw implants on the interfacial autologous bone attachment and bone graft incorporation through in vivo studies. The addition of an optimal amount of BG to Ti-6Al-4V leads to a lower elastic modulus of the ceramic-metal composite material, effectively reducing the stress-shielding effects. Pedicle screw implants with optimal shape design and made of the composite material of Ti-6Al-4V doped with BG fabricated through additive manufacturing exhibit greater osseointegration and a more rapid bone volume fraction during the fracture healing process 120 days after implantation, per in vivo studies.


Assuntos
Alumínio , Desenvolvimento Ósseo , Vidro , Parafusos Pediculares , Pós , Próteses e Implantes , Titânio , Vanádio , Animais , Fenômenos Biomecânicos , Remodelação Óssea , Processamento de Imagem Assistida por Computador , Osseointegração , Estresse Mecânico , Suínos , Tomografia Computadorizada por Raios X
3.
Addit Manuf ; 35: 101322, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32835025

RESUMO

The deformations of isotropic and anisotropic Ti-6Al-4V columnar structures fabricated by additive manufacturing were extensively examined. The distinct texture and microstructure distributions were characterised. In situ X-ray diffraction measurements show different lattice activities resulting from the different microstructure distributions. Spatially resolved mapping revealed manufacturing-induced crystallite-orientation distributions that determine the deformation mechanisms. We propose a self-consistent model to correlate the multi-scale characteristics, from the anisotropic-texture-distribution microstructure to the bulk mechanical properties. We determined that basal and pyramidal slip activities were activated by tension deformation. The underlying additive-manufacturing-induced crystal plasticity plays a major role. We find that the texture development of the columnar structures and the distribution of crystallite orientation achieved by different processing conditions during additive manufacturing have important effects on the mechanical properties. The dominant deformation mode for the anisotropic Ti-6Al-4V columnar structure is basal slip, and that for the isotropic Ti-6Al-4V columnar structure is pyramidal slip. The difference may be important for determining the fatigue behaviour.

4.
J Diet Suppl ; 17(2): 173-183, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-30380357

RESUMO

Hyperlipidemia is one of the leading causes of death and requires lipid-lowering treatment to reduce morbidity and mortality. Effective and safe alternative and adjunctive therapies could be beneficial for patients with hyperlipidemia. To assess the effect of a fiber-multivitamin combination product on the lipid parameters low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), total cholesterol (TC), triglyceride (TG), and apolipoprotein B (Apo B) in patients with hypercholesterolemia, we conducted a double-blind, randomized, parallel-group study. Forty-one out of 50 randomized hypercholesterolemic participants recruited between August 2016 and March 2018 completed the trial. The participants were assigned to receive either test product (treatment group, n = 20) or placebo (placebo group, n = 21) for 4 weeks following a 6-week dietary intervention (based on education from a dietitian) run-in period. The primary outcome was LDL-c levels and the secondary outcomes were HDL-c, TC, TG, and Apo B levels. All of the outcomes were measured at baseline and week 4 after the completion of run-in period. Participants in both groups had similar LDL-c levels (142 ± 15.7 vs. 143 ± 19.3 mg/dL). After 4 weeks of exposure to test product, participants in the treatment group demonstrated a 17.25 ± 22.26 reduction in LDL-c (p < .05 vs. placebo). This improvement in LDL-c was accompanied by amelioration in TC and Apo B levels, without any detrimental effects on HDL and TG concentration. Results of the present study suggest that fiber-vitamin combination has potential to be used as an adjunct therapy for the management of hypercholesterolemia.


Assuntos
Anticolesterolemiantes/administração & dosagem , Fibras na Dieta/administração & dosagem , Suplementos Nutricionais , Hipercolesterolemia/dietoterapia , Vitaminas/administração & dosagem , Adulto , Apolipoproteínas B/sangue , HDL-Colesterol/sangue , LDL-Colesterol/sangue , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Triglicerídeos/sangue
5.
Sci Pharm ; 84(1): 167-79, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27110507

RESUMO

Adverse drug reactions (ADRs) are associated with morbidity, mortality, and can contribute to increased healthcare costs. This study was conducted to identify the occurence, types, and management of ADRs, as well as analyze the causal relationship, severity, and preventability of ADRs. The study was observational analysis with concurrent data collection from patients with Coronary Artery Disease-ST segment Elevation Myocardial Infarction (CAD-STEMI) treated in the Cardiac Intensive Care Unit (CICU) at a hospital in Bandung Indonesia, during the period of December 2013 to March 2014. The occurence of identified ADRs was assessed using the probability scale of Naranjo, while the severity by the scale of Hartwig and their preventability was evaluated using the scale of Schumock-Thornton. 49 ADRs were identified in 29 patients. Organ systems most affected by the ADRs were the cardiovascular and body electrolyte, each accounting for 20.41%. The hematology and gastrointestinal systems each contributed 18.37% to ADR occurrences. The causal relationship was mostly classified as "probable," accounting for 69.39%. With regard to severity, most ADRs were classified as "moderate" at level 3, contributing to 53.06% of the occurence. In terms of preventability, most of the ADRs fell into the "non-preventable" category (79.59%). The most widely applied ADRs management was administration of an antidote or other treatments (40.82%). Further analysis revealed that the average number of drug types and duration of hospitalization significantly affected the presence of ADRs. Taken together, most patients with CAD STEMI treated in the CICU of the studied hospital experienced non-preventable ADRs and were treated with antidote or other treatments.

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