Interplay of Fracture and Martensite Transformation in Microstructures:A Coupled Problem

We are witnessing a tremendous transition towards a society powered by net-zero carbon emission energy, with a corresponding escalating reliance on functional materials (FM). In recent years, the application of FM in multiphysics environments has brought new challenges to the mechanics and materials research communities. The underlying mechanism in FM, which governs several fundamental characteristics, is known as martensitic phase transformation (MPT). When it comes to the application of FM in the multiphysics context, a thorough understanding of the interplay between MPT and fracture plays a crucial role in FM design and application. In the present work, a coupled problem of crack nucleation and propagation and multivariant stress-induced MPT in elastic materials is presented using a finite element method based on Khachaturyan’s microelasticity theory. The problem is established based on a phase-field (PF) approach, which includes the Ginzburg–Landau equations with advanced thermodynamic potential and the variational formulation of Griffith’s theory. Therefore, the model consists of a coupled system of the Ginzburg–Landau equations and the static elasticity equation, and it characterizes evolution of distributions of austenite and two martensitic variants as well as crack growth in terms of corresponding order parameters. The numerical results show that crack growth does not begin until MPT has grown almost completely through the microstructure. Subsequent to the initial formation of the martensite variants, the initial crack propagates in such a way that its path mainly depends on the feature of martensite variant formations, the orientation and direction upon which the martensite plates are aligned, and the stress concentration between martensite plates. In addition, crack propagation behavior and martensite variant evaluations for different lattice orientation angles are presented and discussed in-detail

The effects of probiotic supplementation on gene expression related to inflammation, insulin and lipid in patients with Parkinson�s disease: A randomized, double-blind, placebo-controlled trial

Background: This study was conducted to evaluate the effects of probiotic supplementation on gene expression related to inflammation, insulin and lipid in patients with Parkinson�s disease (PD).Methods: This randomized, double-blind, placebo-controlled clinical trial was conducted in 50 patients with PD as a pilot study. Participants were randomly allocated into two groups to take either 8�109 CFU/day probiotic supplements or placebo (n = 25 each group, one capsule daily) for 12 weeks. Gene expression related to inflammation, insulin, and lipid was quantified in peripheral blood mononuclear cells (PBMC) of PD patients, with RT-PCR method. Results: After the 12-week intervention, compared with the placebo, probiotic intake downregulated gene expression of interleukin-1 (IL-1) (P = 0.03), IL-8 (P < 0.001) and tumor necrosis factor alpha (TNF-α) (P=0.04) in PBMC of subjects with PD. In addition, probiotic supplementation upregulated transforming growth factor beta (TGF-β) (P = 0.02) and peroxisome proliferator-activated receptor gamma (PPAR-γ) (P = 0.03) in PBMC of subjects with PD compared with the placebo. We did not observe any significant effect of probiotic intake on gene expression of low-density lipoprotein receptor (LDLR) and vascular endothelial growth factor (VEGF) in PBMC of patients with PD. Conclusion: Overall, probiotics supplementation for 12 weeks in PD patients significantly improved gene expression of IL-1, IL-8, TNF-α, TGF-β and PPAR-γ, but did not affect gene expression of VEGF and LDLR, and biomarkers of inflammation and oxidative stress. © 2018 The Author(s)

Clinical and metabolic response to probiotic administration in people with Parkinson's disease: A randomized, double-blind, placebo-controlled trial

Background &amp; aims: The investigation was done to assess the impacts of probiotic supplementation on movement and metabolic parameters in individuals with Parkinson's disease (PD). Methods: The study is randomized, double-blind, placebo-controlled clinical trial, which was done in sixty people with PD. Individuals were randomly divided into two groups in order to take either 8 � 109 CFU/day probiotic or placebo (n = 30 each group) that lasted 12 weeks. The Movement Disorders Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) was recorded at pre- and post-intervention. Results: Compared with the placebo, consuming probiotic decreased MDS-UPDRS (�4.8 ± 12.5 vs. +3.8 ± 13.0, P = 0.01). Probiotic supplementation also reduced high-sensitivity C-reactive protein (�1.6 ± 2.5 vs. +0.1 ± 0.3 mg/L, P &lt; 0.001) and malondialdehyde (�0.2 ± 0.3 vs. +0.1 ± 0.3 μmol/L, P = 0.006), and enhanced glutathione levels (+40.1 ± 81.5 vs. �12.1 ± 41.7 μmol/L, P = 0.03) in comparison with the placebo. Additionally, probiotic consumption resulted in a statistically significant reduction in insulin levels (�2.1 ± 3.4 vs. +1.5 ± 5.1 μIU/mL, P = 0.002) and insulin resistance (�0.5 ± 0.9 vs. +0.4 ± 1.2, P = 0.002), and a statistically significant rise in insulin sensitivity (+0.01 ± 0.02 vs. �0.006 ± 0.02, P = 0.01) in comparison with the placebo. Probiotic intake had no any significant impact on other metabolic profiles. Conclusions: Our study evidenced that 12 weeks of probiotic consumption by individuals with PD had useful impacts on MDS-UPDRS and few metabolic profiles. Registered under ClinicalTrials.gov Identifier no. http://www.irct.ir: IRCT2017082434497N4. © 2018 Elsevier Ltd and European Society for Clinical Nutrition and Metabolis

Factors influencing patient satisfaction with dental appearance and treatments they desire to improve aesthetics

Background: We assessed factors influencing patients’ satisfaction with their dental appearance and the treatments they desired to improve dental aesthetics. Methods: A cross-sectional study was performed out among 235 adult patients who visited the Hospital Universiti Sains Malaysia dental clinic. A structured, interviewer-guided questionnaire was used to identify patient satisfaction with their general dental appearance, cosmetic elements and desired treatments. Results: The 235 patients consisted of 70 males (29.8%) and 165 females (70.2%), of mean age 31.5 years (SD 13.0). Of these patients, 124 (52.8%) were not satisfied with their general dental appearance. In addition, 132 patients (56.2%) were not happy with the color of their teeth, 76 (32.3%), regarded their teeth were poorly aligned, 62 (26.4%), as crowded and 56 (23.4%) protruded. Dissatisfaction with tooth color was significantly higher in female than in male patients (odds ratio [OR] of 1.99 (95% confidence interval [CI] 1.13-3.50). Tooth whitening was the treatment most desired by patients (48.1%). Results of multiple logistic regression analysis showed that patient dissatisfaction with general dental appearance was significantly associated with female gender (OR = 2.18; 95% CI: 1.18-4.03), unhappiness with tooth color (OR = 3.05; 95% CI: 1.74-5.34) and the opinion that their teeth protruded (OR = 2.91, 95% CI: 1.44-5.91)

Natural frequency analysis of continuously graded carbon nanotube-reinforced cylindrical shells based on third-order shear deformation theory

Based on the third-order shear deformation theory (TSDT), the investigation of the free vibration response of a continuously graded carbon nanotube-reinforced (CGCNTR) cylindrical shell is presented. The volume fractions of randomly oriented straight single-walled carbon nanotubes are assumed to be graded in the thickness direction. An embedded carbon nanotube in a polymer matrix and its surrounding inter-phase is replaced with an equivalent fiber for predicting the mechanical properties of the carbon nanotube/polymer composite. The Mori–Tanaka scheme as an accurate micromechanics model is used for estimating the homogenized material properties of nanocomposites reinforced with equivalent fibers. The equations of motion and the associated boundary conditions are derived using the Hamilton’s principle based on TSDT. The discretization of the system by means of the Generalized Differential Quadrature Method leads to a standard linear eigenvalue problem. Detailed parametric studies have been carried out to study the impacts of the various types of equivalent fiber distribution, different boundary conditions and geometrical parameters on the vibration characteristics of CGCNTR cylindrical shells. The interesting finding of the present study is that the graded CNT volume fractions with symmetric distribution through the shell thickness have high capabilities to reduce or increase the natural frequency in comparison with uniformly and asymmetric CNT distribution. </jats:p