1,466 research outputs found
Cd3As2 is Centrosymmetric
This is a revised version of a manuscript that was originally posted here in
February of 2014. It has been accepted at the journal Inorganic Chemistry after
reviews that included those of two crystallographers who made sure all the t's
were crossed and the i's were dotted. The old work (from 1968) that said that
Cd3As2 was noncentrosymmetric was mistaken, with the authors of that study
making a type of error that in the 1980s became infamous in crystallography. As
a result of the increased scrutiny of the issue of centrosymmetricity of the
1980's, there are now much better analysis tools to resolve the issue fully,
and its important to understand that not just our crystals are centrosymmetric,
even the old guy's crystals were centrosymmetric (and by implication everyone's
are). There is no shame in having made that error back in the day and those
authors would not find the current centrosymmetric result controversial; their
paper is excellent in all other aspects. This manuscript describes how the
structure is determined, explains the structure schematically, calculates the
electronic structure based on the correct centrosymmetric crystal structure,
and gives the structural details that should be used for future analysis and
modeling.Comment: Accepted by ACS Inorganic Chemistr
Downregulation of plasma MiR-142-3p and MiR-26a-5p in patients with colorectal carcinoma
Background: Colorectal cancer is one of the most commonly diagnosed cancers and cancer- related death worldwide. Identification of new specific biomarkers could be helpful to detection of this malignancy. Altered plasma microRNA expression has been identified in many cancers, including colorectal cancer. Objectives: The main objective of this study was to identify the circulating microRNAs with the most expression changes in colorectal cancer patients compared with neoplasm free healthy individuals. Materials and Methods: MicroRNA expression profiling was performed on plasma samples of 37 colorectal cancer patients and 8 normal subjects using microRNA microarray. Quantitative real-time reverse transcription polymerase chain reaction was used to validate the two selected altered microR NAs. Plasma samples from 61 colorectal cancer patients and 24 normal subjects were used in our validation study. Results: In profiling study we found a panel of six plasma microRNAs with significant downregulation. MicroRNA-142-3p and microRNA-26a-5p were selected and validated by polymerase chain reaction. Our results demonstrated that expression levels of plasma microRNA-142-3p and microRNA-26a-5p were significantly downregulated in patients with colorectal cancer when compared to control group. Conclusions: Our findings suggest that downregulation of plasma microRNA-142-3p and microRNA-26a-5p might serve as novel noninvasive biomarkers in the diagnosis of colorectal cancer, although more studies are needed to highlight the theoretical strengths. © 2015, Iranian Journal of Cancer Prevention
Visualizing pair formation on the atomic scale in the high-Tc superconductor Bi2Sr2CaCu2O8+d
Pairing of electrons in conventional superconductors occurs at the
superconducting transition temperature Tc, creating an energy gap D in the
electronic density of states (DOS). In the high-Tc superconductors, a partial
gap in the DOS exists for a range of temperatures above Tc. A key question is
whether the gap in the DOS above Tc is associated with pairing, and what
determines the temperature at which incoherent pairs form. Here we report the
first spatially resolved measurements of gap formation in a high-Tc
superconductor, measured on Bi2Sr2CaCu2O8+d samples with different Tc values
(hole concentration of 0.12 to 0.22) using scanning tunnelling microscopy. Over
a wide range of doping from 0.16 to 0.22 we find that pairing gaps nucleate in
nanoscale regions above Tc. These regions proliferate as the temperature is
lowered, resulting in a spatial distribution of gap sizes in the
superconducting state. Despite the inhomogeneity, we find that every pairing
gap develops locally at a temperature Tp, following the relation 2D/kBTp = 8.
At very low doping (<0.14), systematic changes in the DOS indicate the presence
of another phenomenon, which is unrelated and perhaps competes with electron
pairing. Our observation of nanometre-sized pairing regions provides the
missing microscopic basis for understanding recent reports of fluctuating
superconducting response above Tc in hole-doped high-Tc copper oxide
superconductors
Functional analyses of recombinant mouse hepcidin-1 in cell culture and animal model
Hepcidin is a peptide hormone that plays an important role in iron metabolism. We have produced a recombinant mouse hepcidin-1 by using baculovirus expression system. Its expression yield was 25 μg/ml when cell culture media were supplemented with a protease inhibitor cocktail. The recombinant mouse hepcidin-1 and synthetic human hepcidin-25 had similar effects on reducing ferroportin expression in J774A cell line and in peritoneal macrophages. However, synthetic human hepcidin-25 was more efficient than recombinant mouse hepcidin-1 in reducing iron concentration in blood circulation (p < 0.01). © 2013 Springer Science+Business Media Dordrecht.
Author keywords
Baculovirus expression system (BES) Ferroportin Hepcidin Iron metabolism
Indexed keyword
Evaluating passive neighborhood discovery for Low Power Listening MAC protocols
Low Power Listening (LPL) MAC protocols are widely used in today's sensors networks for duty cycling. Their simplicity and power efficiency ensures a long network life when nodes are battery driven and their easy deployment and lower cost of maintenance makes them suitable to be used in hard-to-access places and harsh conditions. We argue that to fully utilize energy efficiency provided by LPL, other protocols in the protocol stack should be aware of mechanisms. In this paper, we focus on neighborhood discovery protocols and discuss their energy efficient integration with LPL. Then, we study the possibility of using a completely passive approach for neighborhood discovery in such networks and provide an analytical model for its performance characteristics. We verify our performance model both by simulation and implementation in TinyOS. Our evaluation results confirm the efficiency of our proposed method in duty-cycled sensor networks
Minimal window duration for accurate HRV recording in athletes
Heart rate variability (HRV) is non-invasive and commonly used for monitoring responses to training loads, fitness, or overreaching in athletes. Yet, the recording duration for aseries of RR-intervals varies from 1 to 15 min in the literature. The aim of the present work was to assess the minimum record duration to obtain reliableHRV results. RR-intervalsfrom 159 orthostatic tests (7 min supine, SU, followed by 6 min standing, ST) were analyzed. Reference windows were 4 min in SU (min 3–7) and 4 min in ST (min 9–13).Those windows were subsequently divided and the analyses were repeated on eight different fractioned windows: the first min (0–1), the second min (1–2), the third min (2–3),the fourth min (3–4), the first 2 min (0–2), the last 2 min (2–4), the first 3 min (0–3), and thelast 3 min (1–4). Correlation and Bland & Altman statistical analyses were systematically performed. The analysis window could be shortened to 0–2 instead of 0–4 for RMSSD only, whereas the 4-min window was necessary for LF and total power. Since there is a need for 1 min of baseline to obtain a steady signal prior the analysis window, we conclude that studies relying on RMSSD may shorten the windows to 3 min (=1+2)in SU or seated position only and to 6 min (=1+2 min SU plus 1+2 min ST) if there is an orthostatic test. Studies relying on time- and frequency-domain parameters need a minimum of 5 min (=1+4) min SU or seated position only but require 10 min (=1+4 minSU plus 1+4 min ST) for the orthostatic tes
Supply chain integration strategies in fast evolving industries
Purpose - The purpose of this paper is to define the "fast evolving industry" (FEI) and its supply chain management (SCM) challenges. The authors review and structure the literature regarding integration strategies and implementation methods to develop a strategic decision-making framework for SCM in the FEI.
Design/methodology/approach - The authors conduct a review of SCM literature, including supply chain strategy, supply chain integration (SCI), agile and responsive supply chain and SCM for innovative and fast-changing industries. The authors develop a conceptual model and a decision-making framework and use four mini cases to provide support for the model and framework.
Findings - The FEI, characterised by a high level of innovation and differentiation, short products/services lifecycle and high variety, is yet to be fully defined. Inherent uncertainty in FEI supply systems makes SCM in these industries a complex but strategic task for their managers. The framework and the model offered in this study, which employ a core competency concept and provide risk management strategies, offer a strategic tool for managers and scholars in the field to optimise their integration strategies and to operationalise integration decisions.
Originality/value - Little research has been published on transferable and cross-industrial SCM in FEIs. This paper defines the FEI and its resource-related concerns and then offers a conceptual model and a strategic decision-making framework for SCI in FEIs
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Application of NDT thermographic imaging of aerospace structures
This work aims to address the effectiveness and challenges of Non-Destructive Testing (NDT) inspection and improve the detection of defects without causing damage to the material or operator. It focuses on two types of NDT methods; pulsed thermography and vibrothermography. The paper also explores the possibility of performing automated aerial inspection using an unmanned aerial vehicle (UAV) provided with a thermographic imaging system. The concept of active thermography is discussed for inspecting aircraft CFRP panels along with the proposal for performing aerial inspection using the UAV for real time inspection. Static NDT results and the further UAV research indicate that the UAV inspection approach could significantly reduce the inspection time, cost, and workload, whilst potentially increasing the probability of detection
Nanoscale Proximity Effect in the High Temperature Superconductor Bi-2212
High temperature cuprate superconductors exhibit extremely local nanoscale
phenomena and strong sensitivity to doping. While other experiments have looked
at nanoscale interfaces between layers of different dopings, we focus on the
interplay between naturally inhomogeneous nanoscale regions. Using scanning
tunneling microscopy to carefully track the same region of the sample as a
function of temperature, we show that regions with weak superconductivity can
persist to elevated temperatures if bordered by regions of strong
superconductivity. This suggests that it may be possible to increase the
maximum possible transition temperature by controlling the distribution of
dopants.Comment: To appear in Physical Review Letter
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