The enhancement of the functional properties of materials at reduced dimensions is crucial for continuous advancements in nanoelectronic applications. Here, we report that the scale reduction leads ...to the emergence of an important functional property, ferroelectricity, challenging the long-standing notion that ferroelectricity is inevitably suppressed at the scale of a few nanometers. A combination of theoretical calculations, electrical measurements, and structural analyses provides evidence of room-temperature ferroelectricity in strain-free epitaxial nanometer-thick films of otherwise nonferroelectric strontium titanate (SrTiO3). We show that electrically induced alignment of naturally existing polar nanoregions is responsible for the appearance of a stable net ferroelectric polarization in these films. This finding can be useful for the development of low-dimensional material systems with enhanced functional properties relevant to emerging nanoelectronic devices.
Periodontitis is a bacteria-driven inflammatory destructive disease that leads to attachment loss, bone resorption, and even tooth loss. Accumulating studies revealed that macrophages might play an ...nonnegligible role during the processes of periodontitis. However, the underlying mechanism remains largely unknown. In this study, we found novel Akt2/JNK1/2/c-Jun and Akt2/miR-155-5p/DET1/c-Jun signaling pathways that regulated the polarization of macrophages and altered periodontal inflammatory status. Through hematoxylin and eosin, immunostaining, and immunofluorescence staining of clinical specimens, a higher number of M1 phenotype macrophage infiltration was found in periodontitis than in normal controls. Flow cytometry and immunofluorescence showed that overexpression of Akt2 in RAW 264.7 cells induced M1 macrophage polarization and decreased M2 polarization, while knockdown of Akt2 exerted an opposite effect. Furthermore, overexpression of Akt2 activated the JNK pathway and then increased the release of proinflammatory mediators, while knockdown of Akt2 downregulated the above genes accordingly. Importantly, the macrophage polarization and the subsequent alteration of pathway molecules induced by overexpression of Akt2 could be rescued by Akt2 and JNK inhibitors. Moreover, JNK inhibition could facilitate M2 polarization of macrophages. In a mouse periodontitis model, the novel signaling pathway as well as clinical phenotype was further verified. Inhibition of Akt2 facilitated macrophage M2 polarization and rescued the bone loss due to periodontitis. Collectively, we identified novel Akt2/JNK1/2/c-Jun and Akt2/miR-155-5p/DET1/c-Jun signaling pathways that regulate macrophage polarization and highlight that Akt2 inhibition promotes M2 polarization of macrophages and can be a novel potential candidate in the treatment of periodontitis.
This book aims to present meshfree methods in a friendly and straightforward manner, so that beginners can very easily understand, comprehend, program, implement, apply and extend these methods. It ...provides first the fundamentals of numerical analysis that are particularly important to meshfree methods. Typical meshfree methods, such as EFG, RPIM, MLPG, LRPIM, MWS and collocation methods are then introduced systematically detailing the formulation, numerical implementation and programming. Many well-tested computer source codes developed by the authors are attached with useful descriptions. The application of the codes can be readily performed using the examples with input and output files given in table form. These codes consist of most of the basic meshfree techniques, and can be easily extended to other variations of more complex procedures of meshfree methods. Readers can easily practice with the codes provided to effective learn and comprehend the basics of meshfree methods.
A review of three magnetic NDT technologies Wang, Z.D.; Gu, Y.; Wang, Y.S.
Journal of magnetism and magnetic materials,
February 2012, 2012-02-00, 20120201, Letnik:
324, Številka:
4
Journal Article
Recenzirano
Magnetic techniques are most important NDT technologies to characterize the mechanical features of ferromagnetic materials based on the physical principle of magnetic-stress coupling. A review is ...presented in this paper about the development of the magnetic NDT technologies. After a brief outline of the theoretical studies of the magnetic-stress coupling effect, the three popular magnetic NDT technologies are reviewed, which are magnetic flux leakage (MFL), magnetic Barkhausen noise (MBN) and recently developed metal magnetic memory (MMM). The first two are ascribed to the active magnetic method, and the last one is the passive method. Based on an extensive literature survey in this field, this paper focuses on the discussion of the physical mechanism and some important experimental results relevant to the three NDT technologies. The challenges for each technique in this field are also summarized.
► Review is presented in this paper about three magnetic NDT technologies. ► Magnetic flux leakage (MFL), magnetic Barkhausen noise (MBN) and recently developed metal magnetic memory (MMM). ► Physical mechanism and research development about the three NDT technologies were specially discussed.
CsV3 Sb5 is a newly discovered Z2 topological kagome metal showing the coexistence of a charge-density-wave (CDW)-like order at T* = 94 K and superconductivity (SC) at Tc = 2.5 K at ambient pressure. ...Here, we study the interplay between CDW and SC in CsV3 Sb5 via measurements of resistivity, dc and ac magnetic susceptibility under various pressures up to 6.6 GPa. We find that the CDW transition decreases with pressure and experience a subtle modification at Pc1 ≈ 0.6 – 0.9 GPa before it vanishes completely at Pc2 ≈ 2 GPa . Correspondingly, Tc(P) displays an unusual M -shaped double dome with two maxima around Pc1 and Pc2 , respectively, leading to a tripled enhancement of Tc to about 8 K at 2 GPa. The obtained temperature-pressure phase diagram resembles those of unconventional superconductors, illustrating an intimated competition between CDW-like order and SC. The competition is found to be particularly strong for the intermediate pressure range Pc1 ≤ P ≤ Pc2 as evidenced by the broad superconducting transition and reduced superconducting volume fraction. The modification of CDW order around Pc1 has been discussed based on the band structure calculations. This work not only demonstrates the potential to raise Tc of the V-based kagome superconductors, but also offers more insights into the rich physics related to the electron correlations in this novel family of topological kagome metals.
It is important to consider sagittal pelvic rotation when introducing the acetabular component at total hip arthroplasty (THA). The purpose of this study was to identify patients who are at risk of ...unfavourable pelvic mobility, which could result in poor outcomes after THA.
A consecutive series of 4042 patients undergoing THA had lateral functional radiographs and a low-dose CT scan to measure supine pelvic tilt, pelvic incidence, standing pelvic tilt, flexed-seated pelvic tilt, standing lumbar lordotic angle, flexed-seated lumbar lordotic angle, and lumbar flexion. Changes in pelvic tilt from supine-to-standing positions and supine-to-flexed-seated positions were determined. A change in pelvic tilt of 13° between positions was deemed unfavourable as it alters functional anteversion by 10° and effectively places the acetabular component outside the safe zone of orientation.
For both men and women, the degree of lumbar flexion was a significant predictor of risk in hip flexion (p < 0.0001) with increased odds of unfavourable pelvic mobility in those with lumbar flexion of < 20° (men, odds ratio (OR) 6.74, 95% confidence interval (CI) 3.83 to 11.89; women, OR 2.97, 95% CI 1.87 to 4.71). In women, age and standing pelvic tilt were significant predictors of risk in hip extension (p = 0.0082 and p < 0.0001, respectively). The risk of unfavourable pelvic mobility was higher in those aged > 75 years (OR 2.28, 95% CI 1.56 to 3.32) and those with standing pelvic tilt of < 10° (OR 7.10, 95% CI 4.10 to 10.29). In men, only standing pelvic tilt was significant (p < 0.0001) for hip extension with an increased risk of unfavourable pelvic mobility (OR 8.68, 95% CI 5.19 to 14.51).
Patients found to have unfavourable pelvic mobility had limited lumbar flexion and more posterior standing pelvic tilt in both men and women, as well as increasing age in women. We recommend that patients undergo preoperative functional radiographic screening to determine specific parameters that can affect the functional orientation of the acetabular component. Cite this article: Bone Joint J 2018;100-B:845-52.
A sharp increase in the frequency of earthquakes near Fox Creek, Alberta, began in December 2013 in response to hydraulic fracturing. Using a hydraulic fracturing database, we explore relationships ...between injection parameters and seismicity response. We show that induced earthquakes are associated with completions that used larger injection volumes (10
to 10
cubic meters) and that seismic productivity scales linearly with injection volume. Injection pressure and rate have an insignificant association with seismic response. Further findings suggest that geological factors play a prominent role in seismic productivity, as evidenced by spatial correlations. Together, volume and geological factors account for ~96% of the variability in the induced earthquake rate near Fox Creek. This result is quantified by a seismogenic index-modified frequency-magnitude distribution, providing a framework to forecast induced seismicity.
Much of the attention on diet and Alzheimer's disease (AD) or cognition among the elderly has focused on the role of single nutrients or foods, while available information on dietary pattern (DP) ...analysis, which better reflects the complexity of the diet, is sparse. In this review, we describe different patterning approaches and present studies performed to date that have assessed the associations between DPs and risk of AD or cognitive function in the elderly. Three patterning approaches have been most commonly used: (i) hypothesis-based that use dietary quality indexes or scores (e.g. Mediterranean pattern), (ii) data-driven that use factor or cluster analysis to derive DPs, (iii) reduced rank regression which combines characteristics of the former two approaches. Despite differences existing among the approaches, DPs characterized by higher intake of fruits, vegetables, fish, nuts and legumes, and lower intake of meats, high fat dairy, and sweets seemed to be associated with lower odds of cognitive deficits or reduced risk of AD. Overall, the inherent advantages as well as the existing evidence of DP analyses strongly suggest that this approach may be valuable in AD and aging research. Further studies are warranted, though, to confirm the findings in different population settings, to address some methodological issues, and possibly utilize the information for future clinical trial design.
Pancreatic ductal adenocarcinoma (PDAC) is a highly invasive cancer with a poor prognosis. Although microRNA (miRNA) transcripts have a crucial role in carcinogenesis and development, little ...information is known regarding the aberrant DNA methylation of miRNAs in PDAC. Using methylated DNA immunoprecipitation-chip analysis, we found that miR-615-5p was hypermethylated in its putative promoter region, which silenced its expression in PDAC cell lines. In addition, the overexpression of miR-615-5p in pancreatic cancer cells suppressed cell proliferation, migration and invasion. Insulin-like growth factor 2 (IGF2) is an imprinted gene, and its abnormal expression contributes to tumor growth. Here, we identified IGF2 as a target of miR-615-5p using a luciferase reporter assay. IGF2 upregulation in PDAC tissues was not correlated with a loss of imprinting but was inversely correlated with miR-615-5p downregulation. In addition, miR-615-5p suppressed pancreatic cancer cell proliferation, migration and invasion by directly targeting IGF2, and this effect could be reversed by co-transfection with IGF2. Furthermore, the stable overexpression of miR-615-5p inhibited tumor growth in vivo and was correlated with IGF2 expression. Using RNA sequencing, we further identified miR-615-5p as potentially targeting other genes, such as the proto-oncogene JUNB, and interfering with the insulin signaling pathway. Taken together, our results demonstrate that miR-615-5p was abnormally downregulated in PDAC cells due to promoter hypermethylation, which limited its inhibition of IGF2 and other target genes, thereby contributing to tumor growth, invasion and migration. These data demonstrate a novel and important role of miR-615-5p as a tumor suppressor in PDAC.
PDF
