In this letter, we propose an adaptive forward error correction scheme based on low-density parity-check (LDPC) codes to efficiently adjust dimming values in visible light communication (VLC) ...systems. The proposed code is a quasi-cyclic LDPC code, in which extension and puncturing methods are used to maintain dimming control. The significant advantages of the proposed method are due to the lower number of codes required to support codes with different coding rate and the relatively small performance degradation for dimming control. Simulation results show that our proposed method efficiently maintains the dimming control in VLC systems with LDPC codes.
According to data compiled by researchers at Johns Hopkins University in Baltimore, Maryland, more than two and half million cases of coronavirus disease 2019 (COVID-19), caused by a newly discovered ...virus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), have been confirmed on April 20, 2020 (Nature, 2020b). Since the emergence of this infectious disease in Asia (Wuhan, China) late last year, it has been subsequently span to every continent of the world except Antarctica (Rodríguez-Morales et al., 2020). Along with a foothold in every country, the current disease pandemic is disrupting practically every aspect of life all over the world. As the outbreak are continuing to evolve, several research activities have been conducted for better understanding the origin, functions, treatments, and preventions of this novel coronavirus. This review will be a summa of the key features of novel coronavirus (nCoV), the virus causing disease 2019 and the present epidemic situation worldwide up to April 20, 2020. It is expected that this record will play an important role to take more preventive measures for overcoming the challenges faced during this current pandemic.
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•Novel coronavirus, SARS-CoV-2 is responsible for coronavirus disease 2019 (COVID-19).•SARS-CoV-2 has caused for human-to-human transmission worldwide.•Non-pharmaceutical interventions (NPIs) can reduce the transmission of COVID-19.•COVID-19 is a crisis for massive health hazard, big humanitarian and development.•The use of research-based evidence, global response and solidarity may be helpful.
Planar limits, defined as lines generated by connecting maximum double-bond equivalence (DBE) values at given carbon numbers, are proposed as a means of predicting and understanding the molecular ...structure of compounds in crude oil. The slopes and y-intercepts of the lines are determined by the DBE/carbon number ratios of functional groups defining the planar limits. For example, the planar limit generated by a serial addition of saturated cyclic rings has a slope of 0.25. The planar limit formed by the linear and nonlinear addition of benzene rings yields lines with slopes of 0.75 and 1, respectively. The y-intercepts of these lines were determined by additional functional groups added within a series of molecules. Plots of DBE versus carbon number for S1 class compounds observed by Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) showed that saturates/aromatics/resins/asphaltenes (SARA) fractions exhibited unique slopes and y-intercepts. The slope of the planar limit observed from a saturates fraction matched well with the slope of a planar limit generated by the serial addition of saturated cyclic rings. The slopes of planar limits of aromatics and resins fractions were very similar to that obtained from the linear addition of benzene rings. Finally, the slope of the asphaltenes fraction was almost identical to the slope obtained from the nonlinear addition of benzene rings. Simulated and experimental data show that SARA fractions exhibit different molecular structure characteristics. On the basis of the slope and y-intercept of the planar limit, the structures of molecules in SARA fractions were predicted and suggested. The use of planar limits for structural interpretation is not limited to crude oil compounds but can also be used to study other organic mixtures such as humic substances or metabolites.
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•Porous carbon derived from a MOF was studied for adsorptive purification of water.•PCDM-1000 was found as excellent adsorbents for both ibuprofen and diclofenac.•The main adsorption ...mechanism (H-bond) could be confirmed.•The direction of H-bond could be defined (H-donor: PCDM, H-acceptor: adsorbates).•PCDM-1000 was suggested as easy recyclable and highly efficient adsorbents.
A metal-organic framework (MOF) (here, zeolitic-imidazolate framework-8) was pyrolyzed at different temperatures (800, 1000, and 1200°C) in order to prepare porous carbons derived from MOF (PCDMs). Adsorption of ibuprofen (IBP) and diclofenac sodium (DCF) from aqueous solutions was carried out over the produced PCDMs and compared with that over pristine MOF and commercial activated carbon (AC). Among the tested adsorbents, the PCDM prepared at 1000°C (PCDM-1000) was found to be the best candidate for both IBP and DCF. The maximum adsorption capacities of IBP (320mg/g) and DCF (400mg/g) over PCDM-1000 were ∼3 and ∼5 times, respectively, of that of AC. Interaction mechanisms such as H-bonding (H-donation from PCDM, H-acceptance from IBP or DCF) were suggested based on the effect of solution pH on the zeta potential of PCDM and the adsorbed quantity of IBP and DCF along with functional groups created on the surface of PCDM-1000. Finally, PCDM-1000 was confirmed to be as a highly efficient and recyclable adsorbent having potential applications in water purification.
Deformable and conformal silk hydrogel inverse opal Min, Kyungtaek; Kim, Sookyoung; Kim, Sunghwan
Proceedings of the National Academy of Sciences - PNAS,
06/2017, Letnik:
114, Številka:
24
Journal Article
Recenzirano
Odprti dostop
Photonic crystals (PhCs) efficiently manipulate photons at the nanoscale. Applying these crystals to biological tissue that has been subjected to large deformation and humid environments can lead to ...fascinating bioapplications such as in vivo biosensors and artificial ocular prostheses. These applications require that these PhCs have mechanical durability, deformability, and biocompatibility. Herein, we introduce a deformable and conformal silk hydrogel inverse opal (SHIO); the photonic lattice of this 3D PhC can be deformed by mechanical strain. This SHIO is prepared by the UV cross-linking of a liquid stilbene/silk solution, to give a transparent and elastic hydrogel. The pseudophotonic band gap (pseudo-PBG) of this material can be stably tuned by deformation of the photonic lattice (stretching, bending, and compressing). Proof-of-concept experiments demonstrate that the SHIO can be applied as an ocular prosthesis for better vision, such as that provided by the tapeta lucida of nocturnal or deep-sea animals.
Abstract
The National Center for Biotechnology Information (NCBI) produces a variety of online information resources for biology, including the GenBank® nucleic acid sequence database and the PubMed® ...database of citations and abstracts published in life science journals. NCBI provides search and retrieval operations for most of these data from 35 distinct databases. The E-utilities serve as the programming interface for the most of these databases. Resources receiving significant updates in the past year include PubMed, PMC, Bookshelf, RefSeq, SRA, Virus, dbSNP, dbVar, ClinicalTrials.gov, MMDB, iCn3D and PubChem. These resources can be accessed through the NCBI home page at https://www.ncbi.nlm.nih.gov.
This article presents a unified framework analysis for downlink terahertz (THz)-based multiple-input single-output (MISO) rate-splitting multiple-access (RSMA) systems under spherical stochastic ...models. To simultaneously achieve the users' full diversity gain, a novel precoding weight design is proposed based on zero-forcing and maximum-ratio transmission approaches. Accordingly, closed-form expressions for the users' outage probability (OP) and throughput are derived in exact, approximate, and asymptotic manners. Additionally, the users' OP minimization problems are formulated and proven to be strictly convex with regard to the common power allocation (PA) factor. To clarify whether RSMA is superior to non-orthogonal multiple access (NOMA) in future THz communication networks, the OP and throughput comparisons have been carried out. Numerical results confirm that: 1) our theoretical analyses exactly match the simulation results; 2) as for OP aspects, RSMA is not fully superior to NOMA in two-user cases, while for multi-users, it only outperforms NOMA in cases where imperfect successive interference cancellation process produces over 10% residual interference; and 3) as for throughput aspects, RSMA achieves the performance superiority over both two- and multi-users scenarios when compared to its counterparts.
Owing to the increasing environmental and climate changes globally, there is an increasing interest in the molecular‐level understanding of environmental organic compound mixtures, that is, the ...pursuit of complete and detailed knowledge of the chemical compositions and related chemical reactions. Environmental organic molecule mixtures, including those in air, soil, rivers, and oceans, have extremely complex and heterogeneous chemical compositions. For their analyses, ultrahigh‐resolution and sub‐ppb level mass accuracy, achievable using Fourier‐transform ion cyclotron resonance mass spectrometry (FT‐ICR MS), are important. FT‐ICR MS has been successfully used to analyze complex environmental organic molecule mixtures such as natural, soil, particulate, and dissolved organic matter. Despite its success, many limitations still need to be overcome. Sample preparation, ionization, structural identification, chromatographic separation, and data interpretation are some key areas that have been the focus of numerous studies. This review describes key developments in analytical techniques in these areas to aid researchers seeking to start or continue investigations for the molecular‐level understanding of environmental organic compound mixtures.
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