3,278 research outputs found
Enhancing 2D Growth of Organic Semiconductor Thin Films with Macroporous Structures via a Small-Molecule Heterointerface
The physical structure of an organic solid is strongly affected by the surface of the underlying substrate. Controlling this interface is an important issue to improve device performance in the organic electronics community. Here we report an approach that utilizes an organic heterointerface to improve the crystallinity and control the morphology of an organic thin film. Pentacene is used as an active layer above, and m-bis(triphenylsilyl) benzene is used as the bottom layer. Sequential evaporations of these materials result in extraordinary morphology with far fewer grain boundaries and myriad nanometre-sized pores. These peculiar structures are formed by difference in molecular interactions between the organic layers and the substrate surface. The pentacene film exhibits high mobility up to 6.3 cm(2)V(-1)s(-1), and the pore-rich structure improves the sensitivity of organic-transistor-based chemical sensors. Our approach opens a new way for the fabrication of nanostructured semiconducting layers towards high-performance organic electronics.X116049Nsciescopu
Optimal Frequency Intensity of Physical Activity to Reduce the Risk of Hypertension in the Korean Population
PURPOSE: Regular physical activity (PA) is an effective lifestyle modification for preventing hypertension. This study aimed to analyze the optimal frequency of PA required to reduce the incidence of hypertension in the Korean population. Most Korean studies have included only small samples and limited age ranges. METHODS: The present study analyzed 16,299,865 participants aged ≥20 years (44.25±12.74 years) from the 2009 to 2012 Korean National Health Insurance Corporation Survey database. The International Physical Activity Questionnaire was used to assess the frequency and intensity of physical activity. Hazard ratios for incident hypertension were analyzed by physical activity participation, age, and sex using multivariable Cox proportional hazard models, with a non-regular physical activity group as reference. RESULTS: A total of 1,322,674 cases of incident hypertension were identified during the mean follow-up period of over 3 years. Hazard ratios for incident hypertension increased with age, with values of 50.4 and 56.1 for men and women in the older age group, respectively. Hazard ratios for incident hypertension were significantly lower in the regular PA group of middle-aged (4%) and older (7%) adults than in the non-regular PA group. The study revealed that moderate-to-vigorous-intensity PA 3-5 times/week was most effective in reducing the risk of incident hypertension in middle-aged and older adults but not in young adults. We observed no additional lowering of incident hypertension risk in the group undergoing moderate-to-vigorous PA at a frequency of 6-7 days/week compared to the 35 days/week group. CONCLUSIONS: We suggest PA at a frequency of 3-5 times/week for the prevention of incident hypertension in Korean adults
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The Influence of Electron Beam Sterilization on In Vivo Degradation of β-TCP/PCL of Different Composite Ratios for Bone Tissue Engineering.
We evaluated the effect of electron beam (E-beam) sterilization (25 kGy, ISO 11137) on the degradation of β-tricalcium phosphate/polycaprolactone (β-TCP/PCL) composite filaments of various ratios (0:100, 20:80, 40:60, and 60:40 TCP:PCL by mass) in a rat subcutaneous model for 24 weeks. Volumes of the samples before implantation and after explantation were measured using micro-computed tomography (micro-CT). The filament volume changes before sacrifice were also measured using a live micro-CT. In our micro-CT analyses, there was no significant difference in volume change between the E-beam treated groups and non-E-beam treated groups of the same β-TCP to PCL ratios, except for the 0% β-TCP group. However, the average volume reduction differences between the E-beam and non-E-beam groups in the same-ratio samples were 0.76% (0% TCP), 3.30% (20% TCP), 4.65% (40% TCP), and 3.67% (60% TCP). The E-beam samples generally had more volume reduction in all experimental groups. Therefore, E-beam treatment may accelerate degradation. In our live micro-CT analyses, most volume reduction arose in the first four weeks after implantation and slowed between 4 and 20 weeks in all groups. E-beam groups showed greater volume reduction at every time point, which is consistent with the results by micro-CT analysis. Histology results suggest the biocompatibility of TCP/PCL composite filaments
Detection and monitoring of forest fires using Himawari-8 geostationary satellite data in South Korea
Geostationary satellite remote sensing systems are a useful tool for forest fire detection and monitoring because of their high temporal resolution over large areas. In this study, we propose a combined 3-step forest fire detection algorithm (i.e., thresholding, machine learning-based modeling, and post processing) using Himawari-8 geostationary satellite data over South Korea. This threshold-based algorithm filtered the forest fire candidate pixels using adaptive threshold values considering the diurnal cycle and seasonality of forest fires while allowing a high rate of false alarms. The random forest (RF) machine learning model then effectively removed the false alarms from the results of the threshold-based algorithm (overall accuracy ~99.16%, probability of detection (POD) ~93.08%, probability of false detection (POFD) ~0.07%, and 96% reduction of the false alarmed pixels for validation), and the remaining false alarms were removed through post-processing using the forest map. The proposed algorithm was compared to the two existing methods. The proposed algorithm (POD ~ 93%) successfully detected most forest fires, while the others missed many small-scale forest fires (POD ~ 50-60%). More than half of the detected forest fires were detected within 10 min, which is a promising result when the operational real-time monitoring of forest fires using more advanced geostationary satellite sensor data (i.e., with higher spatial and temporal resolutions) is used for rapid response and management of forest fires
Discovery From Non-Parties (Third-Party Discovery) in International Arbitration
International arbitration rules and many arbitration laws usually provide procedures that permit tribunals to order parties to disclose documents and other materials to the other parties.1 More complex are the rules that determine opportunities to obtain discovery from persons that are not party to the arbitration (third-party discovery). This article will review third-party discovery under the Federal Arbitration Act (FAA) and the provisions of the US Code s.1782 that authorise US courts to act in aid of actions before foreign tribunals. Section 1782 has unique interest at this time because it figured prominently in the EU antitrust investigation of Intel that was initiated on request from Advanced Micro Devices (AMD). Early in that investigation, AMD filed a s.1782 request in the US District Court to obtain evidence from US sources for submission to the DG-Competition of the European Commission (EC). This request ultimately led to the Supreme Court’s decision in Intel Corp v Advanced Micro Devices Inc2 which appeared to significantly expand the scope of s.1782. Ironically, after AMD won on key legal issues in the Supreme Court, the District Court on remand exercised its discretion and denied the request for judicial assistance. This paper first describes the FAA non-party discovery rules and the split among the federal appellate courts concerning the authority of arbitrators to order prehearing discovery from non-parties. Next, it provides an analysis of the meaning of the terms “interested party” and “tribunal”—terms that were controversially interpreted by the Supreme Court in Intel and are essential to the application of s.1782. Finally, it discusses the “discretionary” factors used by the federal courts in deciding whether to grant a s.1782 request even when the statutory criteria are met. The opportunity to exercise this discretion seems to rebut the argument that the Supreme Court’s interpretation of s.1782 gives participants before foreign tribunals more discovery rights in the United States than are available to the parties in arbitrations covered by the FAA
A Statistical Verification Method of Random Permutations for Hiding Countermeasure Against Side-Channel Attacks
As NIST is putting the final touches on the standardization of PQC (Post
Quantum Cryptography) public key algorithms, it is a racing certainty that
peskier cryptographic attacks undeterred by those new PQC algorithms will
surface. Such a trend in turn will prompt more follow-up studies of attacks and
countermeasures. As things stand, from the attackers' perspective, one viable
form of attack that can be implemented thereupon is the so-called "side-channel
attack". Two best-known countermeasures heralded to be durable against
side-channel attacks are: "masking" and "hiding". In that dichotomous picture,
of particular note are successful single-trace attacks on some of the NIST's
PQC then-candidates, which worked to the detriment of the former: "masking". In
this paper, we cast an eye over the latter: "hiding". Hiding proves to be
durable against both side-channel attacks and another equally robust type of
attacks called "fault injection attacks", and hence is deemed an auspicious
countermeasure to be implemented. Mathematically, the hiding method is
fundamentally based on random permutations. There has been a cornucopia of
studies on generating random permutations. However, those are not tied to
implementation of the hiding method. In this paper, we propose a reliable and
efficient verification of permutation implementation, through employing
Fisher-Yates' shuffling method. We introduce the concept of an n-th order
permutation and explain how it can be used to verify that our implementation is
more efficient than its previous-gen counterparts for hiding countermeasures.Comment: 29 pages, 6 figure
Room-temperature polariton lasing in quantum heterostructure nanocavities
Controlling light-matter interactions in solid-state systems has motivated
intense research to produce bosonic quasi-particles known as
exciton-polaritons, which requires strong coupling between excitons and cavity
photons. Ultra-low threshold coherent light emitters can be achieved through
lasing from exciton-polariton condensates, but this generally requires
sophisticated device structures and cryogenic temperatures. Polaritonic
nanolasers operating at room temperature lie on the crucial path of related
research, not only for the exploration of polariton physics at the nanoscale
but also for potential applications in quantum information systems, all-optical
logic gates, and ultra-low threshold lasers. However, at present, progress
toward room-temperature polariton nanolasers has been limited by the thermal
instability of excitons and the inherently low quality factors of nanocavities.
Here, we demonstrate room-temperature polaritonic nanolasers by designing
wide-gap semiconductor heterostructure nanocavities to produce thermally stable
excitons coupled with nanocavity photons. The resulting mixed states of
exciton-polaritons with Rabi frequencies of approximately 370 meV enable
persistent polariton lasing up to room temperature, facilitating the
realization of miniaturized and integrated polariton systems
Phase Transition Behavior of Poly(N-isopropylacrylamide-co-N,Ndimethylaminopropylacrylamide) Hydrogels
The copolymer hydrogel of N-isopropylacrylamide (NIPAAm) and N,N-dimethylaminopropylacrylamide (DMAPAA) was synthesized by free radical copolymerization. The phase transition behavior of p(NIPAAmco-DMAPAA) hydrogels as a function of temperature and SDS concentration was studied. The p(NIPAAmco-DMAPAA) hydrogels exhibited larger swelling capacity than the homo p(NIPAAm) hydrogel. The phase transition temperature of p(NIPAAm-co-DMAPAA) hydrogels increased with an increase of DMAPAA content. In aqueous SDS solution, the swelling capacity of p(NIPAAm-co-DMAPAA) hydrogel decreased with an increase of SDS concentration. The phase transition temperature of p(NIPAAm-co-DMAPAA) hydrogels was found to be almost independent of the SDS concentration
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