1,431 research outputs found
Evaluating the miR-302b and miR-145 expression in formalin-fixed paraffin-embedded samples of esophageal squamous cell carcinoma
Background: MicroRNAs are involved in key cellular processes regulating, and their misregulation is linked to cancer. The miR-302-367 cluster is exclusively expressed in embryonic stem and carcinoma cells. This cluster also promotes cell reprogramming and stemness process. In contrast, miR-145 is mostly regarded as a tumor suppressor, where it regulates cellular functions such as cell division, differentiation, and apoptosis. By suppressing the main pluripotency factors (OCT4, SOX2, MYC and KLF4), miR-145 silences the self-renewal program in ESCs. Therefore, the main aim of this study is to find a potential link between the expression level of hsa-miR-302b and hsa-miR-145 with tumor vs. non-tumor as well as high-grade vs. low-grade states of the esophageal tissue samples. Methods: A total number of 40 formalin-fixed, paraffin-embedded (FFPE) samples of esophageal squamous-cell carcinoma (ESCC) were obtained, and the tumor and marginal non-tumor areas delineated and punched off by an expert pathologist. Total RNA was extracted with Trizol, and cDNA synthesized using the miRCURY LNA™ Universal RT microRNA PCR Kit. Real-time reverse transcription polymerase chain reaction (RT-PCR) assays were performed using specific LNA-primers and SYBR Green master mix. Results: The expression level of miR-302b failed to show any significant difference, neither between tumor and their non-tumor counterparts, nor among tumors with different grades of malignancies (P > 0.05). In contrast, miR-145 was significantly down regulated in all grades of tumor samples (P 0.05). CONCLUSION: Our data revealed a significant down-regulation of miR-145 in ESCC tissue samples. Based on our ROC curve analysis data (AUC = 0.74, P < 0.001) miR-145 could be regarded as a potential tumor marker for diagnosis of esophageal cancer. © 2015, Academy of Medical Sciences of I.R. Iran. All rights reserved
Using TurbSim stochastic simulator to improve accuracy of computational modelling of wind in the built environment
Small wind turbines are often sited in more complex environments than in open terrain. These sites include locations near buildings, trees and other obstacles, and in such situations, the wind is normally highly three-dimensional, turbulent, unstable and weak. There is a need to understand the turbulent flow conditions for a small wind turbine in the built environment. This knowledge is crucial for input into the design process of a small wind turbine to accurately predict blade fatigue loads and lifetime and to ensure that it operates safely with a performance that is optimized for the environment. Computational fluid dynamics is a useful method to provide predictions of local wind flow patterns and to investigate turbulent flow conditions at small wind turbine sites, in a manner that requires less time and investment than actual measurements. This article presents the results of combining a computational fluid dynamics package (ANSYS CFX software) with a stochastic simulator (TurbSim) as an approach to investigate the turbulent flow conditions on the rooftop of a building where small wind turbines are sited. The findings of this article suggest that the combination of a computational fluid dynamics package with the TurbSim stochastic simulator is a promising tool to assess turbulent flow conditions for small wind turbines on the roof of buildings. In particular, in the prevailing wind direction, the results show a significant gain in accuracy in using TurbSim to generate wind speed and turbulence kinetic energy profiles for the inlet of the computational fluid dynamics domain rather than using a logarithmic wind-speed profile and a pre-set value of turbulence intensity in the computational fluid dynamics code. The results also show that small wind turbine installers should erect turbines in the middle of the roof of the building and avoid the edges of the roof as well as areas on the roof close to the windward and leeward walls of the building in the prevailing wind direction
Spatiotemporal Organization of Electromechanical Phase Singularities during High-Frequency Cardiac Arrhythmias
Ventricular fibrillation (VF) is a lifethreatening electromechanical
dysfunction of the heart associated with complex spatiotemporal dynamics of
electrical excitation and mechanical contraction of the heart muscle. It has
been hypothesized that VF is driven by three-dimensional (3D) rotating
electrical scroll waves, which can be characterized by filament-like electrical
phase singularities (EPS). Recently, it was shown that rotating excitation
waves during VF are associated with rotating waves of mechanical deformation.
3D mechanical scroll waves and mechanical filaments describing their rotational
core were observed in the ventricles by using high-resolution ultrasound. The
findings suggest that the spatiotemporal organization of cardiac fibrillation
may be assessed from waves of mechanical deformation. However, the complex
relationship between excitation and mechanical waves during VF is currently not
understood. Here, we study the fundamental nature of mechanical phase
singularities (MPS), their spatiotemporal organization and relation with EPS.
We demonstrate the existence of two fundamental types of MPS: "paired
singularities", which are co-localized with EPS, and "unpaired singularities",
which can form independently. We show that the unpaired singularities emerge
due to the anisotropy of the active force field, generated by fiber anisotropy
in cardiac tissue, and the non-locality of elastic interactions, which jointly
induce strong spatiotemporal inhomogeneities in the strain fields. The
inhomogeneities lead to the breakup of deformation waves and create MPS, even
in the absence of EPS, which are typically associated with excitation wave
break. We exploit these insights to develop an approach to discriminate paired
and unpaired MPS. Our findings provide a fundamental understanding of the
complex spatiotemporal organization of electromechanical waves in the heart.Comment: 23 pager, 17 figure
Rapid, cost-effective, sensitive and quantitative detection of Acinetobacter baumannii from pneumonia patients
BACKGROUND AND OBJECTIVES:
Pneumonia with Acinetobacter baumannii has a major therapeutic problem in health care settings. Decision to initiate correct antibiotic therapy requires rapid identification and quantification of organism. The aim of this study was to develop a rapid and sensitive method for direct detection of A. baumannii from respiratory specimens.
MATERIALS AND METHODS:
A Taqman real time PCR based on the sequence of bla(oxa-51) was designed and used for direct detection of A. baumannii from 361 respiratory specimens of patients with pneumonia. All specimens were checked by conventional bacteriology in parallel.
RESULTS:
The new real time PCR could detect less than 200 cfu per ml of bacteria in specimens. There was agreement between the results of real time PCR and culture (Kappa value 1.0, p value<0.001). The sensitivity, specificity and predictive values of real time PCR were 100%. The prevalence of A. baumannii in pneumonia patients was 10.53 % (n=38). Poly-microbial infections were detected in 65.71% of specimens.
CONCLUSION:
Acinetobacter baumannii is the third causative agent in nosocomial pneumonia after Pseudomonas aeroginosa (16%) and Staphylococcus aureus (13%) at Tehran hospitals. We recommend that 104 CFU be the threshold for definition of infection with A. baumannii using real time PCR
Hybrid cities and new working spaces – The case of Oslo
Recent decades have seen the emergence of hybrid models of living and working associated typologies. These developments have been analysed from the perspective of different disciplines, each with their own interpretation of this phenomenon. Planning and architecture have addressed hybridization as a specific form of interaction between spatio-functional features (such as mixed use, multi-functionality and flexibility) and social features (such as formal and informal interactions and the spontaneous appropriation of spaces) or have sometimes simply focused on the spatio-functional dimension in urban spaces. Studies from other disciplines (e.g. mobility networks, transportation, sociology and information technology) have shown that hybrid spaces cannot exist without access to digitalization technologies. Such technologies are accelerating hybridization processes. This study examines the complex and layered phenomenon of hybridization as a possible combination of (or interaction between) spatio-functional, social and digital features within the planning debate and related fields. Most of the case studies explored by scholars so far have focused on interactions occurring between residential, social and recreational functions, but working functions are playing an increasingly important role. Furthermore, the COVID-19 pandemic has accelerated the development of new forms of hybridity in cities. As a consequence, the rising use of hybrid (on-site and on-line) working practices, planners, policy makers and stakeholders, as well as scholars, have increasingly discussed the concept of hybridization. In this context, various hybrid typologies of urban spaces have materialized in forms such as new working spaces (NWS) which include co-working spaces, incubators, as well as some cafés and multi-functional public libraries, which have recently provided working spaces. This paper focuses on the evolving concept of hybridity from the planning perspective. Based on five hybrid NWS including their surrounding neighbourhoods in Oslo, it provides empirical evidence for an understanding of the phenomenon that may support the development of hybrid spaces and buildings and develops suggestions for planning strategies. © 2022 The Author
Electron-based crystalline undulator
We discuss the features of a crystalline undulator of the novel type based on
the effect of a planar channeling of ultra-relativistic electrons in a
periodically bent crystals. It is demonstrated that an electron-based undulator
is feasible in the tens of GeV range of the beam energies, which is noticeably
higher than the energy interval allowed in a positron-based undulator.
Numerical analysis of the main parameters of the undulator as well as the
characteristics of the emitted undulator radiation is carried out for 20 and 50
GeV electrons channeling in diamond and silicon crystals along the (111)
crystallographic planes.Comment: 16 pages, 8 figures, Latex, IOP styl
Classical and quantum spinor cosmology with signature change
We study the classical and quantum cosmology of a universe in which the
matter source is a massive Dirac spinor field and consider cases where such
fields are either free or self-interacting. We focus attention on the spatially
flat Robertson-Walker cosmology and classify the solutions of the
Einstein-Dirac system in the case of zero, negative and positive cosmological
constant . For , these solutions exhibit signature
transitions from a Euclidean to a Lorentzian domain. In the case of massless
spinor fields it is found that signature changing solutions do not exist when
the field is free while in the case of a self-interacting spinor field such
solutions may exist. The resulting quantum cosmology and the corresponding
Wheeler-DeWitt equation are also studied for both free and self interacting
spinor fields and closed form expressions for the wavefunction of the universe
are presented. These solutions suggest a quantization rule for the energy.Comment: 13 pages, 4 figure
A quantum cosmology and discontinuous signature changing classical solutions
We revisit the classical and quantum cosmology of a universe in which a self
interacting scalar field is coupled to gravity with a flat FRW type metric
undergoing continuous signature transition. We arrange for quantum
cosmologically allowed discontinuity in the classical solutions at the
signature changing hypersurface, provided these solutions be dual in some
respects. This may be of some importance in the study of early universe within
the signature changing scenarios.Comment: 11 pages, Latex, title and abstract changed, some cghanges in the
text, to appear in GR
An analytical solution for the elastic response to surface loads imposed on a layered, transversely isotropic and self-gravitating Earth
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