pinecone/core-2020-05-10-deduplication huggingface dataset:
Nonvolatile Reconfigurable Phase-Change Metadevices for Beam Steering in the Near Infrared

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this recordThe development of flat, compact beam-steering devices with no bulky moving parts is opening up a new route to a variety of exciting applications, such as LIDAR scanning systems for autonomous vehicles, robotics and sensing, free-space, and even surface wave optical signal coupling. In this paper, the design, fabrication and characterization of innovative, nonvolatile, and reconfigurable beam-steering metadevices enabled by a combination of optical metasurfaces and chalcogenide phase-change materials is reported. The metadevices reflect an incident optical beam in a mirror-like fashion when the phase-change layer is in the crystalline state, but reflect anomalously at predesigned angles when the phase-change layer is switched into its amorphous state. Experimental angle-resolved spectrometry measurements verify that fabricated devices perform as designed, with high efficiencies, up to 40%, when operating at 1550 nm. Laser-induced crystallization and reamorphization experiments confirm reversible switching of the device. It is believed that reconfigurable phase-change-based beam-steering and beam-shaping metadevices, such as those reported here, can offer real applications advantages, such as high efficiency, compactness, fast switching times and, due to the nonvolatile nature of chalcogenide phase-change materials, low power consumption.C.D.W. acknowledges funding via the US Naval Research LaboratoriesONRG programme (#N62909-16-1-2174) and the EPSRC ChAMP and WAFT grants (EP/M015130/1 and EP/M015173/1). C.R.d.G. acknowledges funding via the EPSRC CDT in Metamaterials (EP/L015331/1). M.L.G. acknowledges funding via the EPSRC grant EP/M009033/1
Ultrahigh performance nanoengineered graphene-concrete composites for multifunctional applications.

There is a constant drive for development of ultrahigh performance multifunctional construction materials by the modern engineering technologies. These materials have to exhibit enhanced durability and mechanical performance, and have to incorporate functionalities that satisfy multiple uses in order to be suitable for future emerging structural applications. There is a wide consensus in the research community that concrete, the most used construction material worldwide, has to be engineered at the nanoscale, where its chemical and physiomechanical properties can be truly enhanced. Here, an innovative multifunctional nanoengineered concrete showing an unprecedented range of enhanced properties when compared to standard concrete, is reported. These include an increase of up to 146% in the compressive and 79.5% in the flexural strength, whilst at the same time an enhanced electrical and thermal performance is found. A surprising decrease in water permeability by nearly 400% compared to normal concrete makes this novel composite material ideally suitable for constructions in areas subject to flooding. The unprecedented gamut of functionalities that are reported in this paper are produced by the addition of water‐stabilized graphene dispersions, an advancement in the emerging field of nanoengineered concrete which can be readily applied in a more sustainable construction industry
Graphene Microstrip Patch Ultrawide Band Antennas for THz Communications

Future generation local communication systems will need to employ THz\ud
frequency bands capable of transferring sizable amounts of data. Current THz technology via\ud
electrical excitation is limited by the upper limits of device cutoff frequencies and by the\ud
lower limits of optical transitions in quantum confined structures. Current metallic THz\ud
antennas require high power to overcome scattering losses and tend to have low antenna\ud
efficiency. We show here via calculation and simulation that graphene can sustain\ud
electromagnetic propagation at THz frequencies via engineering the intra- and interband contributions to the dynamical conductivity to produce a variable surface impedance\ud
microstrip antenna with a several hundred GHz bandwidth. We report the optimization of a\ud
circular graphene microstrip patch antenna on silicon with an optimized return loss of -26 dB,\ud
a -10 dB bandwidth of 504 GHz and an antenna efficiency of -3.4 dB operating at a frequency\ud
of 2 THz. An improved antenna efficiency of -0.36 dB can be found at 3.5 THz but is\ud
accompanied by a lower bandwidth of about 200 GHz. Such large bandwidths and antenna\ud
efficiencies offers significant hope for graphene based flexible directional antennas that can\ud
be employed for future THz local device-to-device communications
Conjugated polymer nanoparticles - Graphene oxide charge -Transfer complexes

The game-changing role of graphene oxide (GO) in tuning the excitonic behavior of\ud
conjugated polymer nanoparticles is described for the first time. This is demonstrated by\ud
using poly(3-hexylthiophene) (P3HT) as a benchmark conjugated polymer and employing an\ud
in-situ re-precipitation approach resulting in P3HT nanoparticles (P3HTNPs) with sizes of 50 -\ud
100 nm in intimate contact with GO. During the self-assembly process, GO changes the\ud
crystalline packing of P3HT chains in the forming P3HTNPs from H to H/J aggregates\ud
exhibiting exciton coupling constants as low as 2 meV, indicating favorable charge separation\ud
along the P3HT chains. Concomitantly, π-π interface interactions between the P3HTNPs and\ud
GO sheets are established resulting in the creation of P3HTNPs-GO charge-transfer complexes\ud
whose energy bandgaps are lowered by up to 0.5 eV. Moreover, their optoelectronic\ud
properties, pre-established in the liquid phase, are retained when processed into thin films\ud
from the stable aqueous dispersions, thus eliminating the critical dependency on external processing parameters. These results can be transferred to other types of conjugated polymers.\ud
Combined with the possibility of employing water based “green” processing technologies,\ud
charge-transfer complexes of conjugated polymer nanoparticles and GO open new pathways\ud
for the fabrication of improved optoelectronic thin film devices.This work has received funding from the European Union's Horizon 2020 research and\ud
innovation programme under the Marie Skłodowska-Curie grant agreement No 642742. AMB,\ud
and WKM acknowledge Spanish MINEICO (project ENE2016-79282-C5-1-R) and the\ud
Gobierno de Aragón (Grupo Reconocido DGA T03_17R), and associated EU Regional\ud
Development Funds).Peer reviewe
Micromachining-compatible, facile fabrication of polymer nanocomposite spin crossover actuators

[FeII(Htrz)2(trz)](BF4) spin crossover particles of 85 nm mean size are dispersed in an SU‐8 polymer matrix and spray‐coated onto silicon microcantilevers. The subsequent photothermal treatment of the polymer resist leads to micrometer thick, smooth, and homogeneous coatings, which exhibit well‐reproducible actuation upon the thermally induced spin transition. The actuation amplitude as a function of temperature is accurately determined by combining integrated piezoresistive detection with external optical interferometry, which allows for the assessment of the associated actuation force (9.4 mN), stress (28 MPa), strain (1.0%), and work density (140 mJ cm−3) through a stratified beam model. The dynamical mechanical characterization of the films evidences an increase of the resonance frequency and a concomitant decrease of the damping in the high‐temperature phase, which arises due to a combined effect of the thickness and mechanical property changes. The spray‐coating approach is also successfully extended to scale up the actuators for the centimeter range on a polymer substrate providing perspectives for biomimetic soft actuators
Tunable volatility of Ge2Sb2Te5 in integrated photonics

This is the final version. Available from the publisher via the DOI in this record.The operation of a single class of optical materials in both a volatile and nonvolatile manner is becoming increasingly important in many applications. This is particularly true in the newly emerging field of photonic neuromorphic computing, where it is desirable to have both volatile (short-term transient) and nonvolatile (long-term static) memory operation, for instance, to mimic the behavior of biological neurons and synapses. The search for such materials thus far have focused on phase change materials where typically two different types are required for the two different operational regimes. In this paper, a tunable volatile/nonvolatile response is demonstrated in a photonic phase-change memory cell based on the commonly employed nonvolatile material Ge2Sb2Te5 (GST). A time-dependent, multiphysics simulation framework is developed to corroborate the experimental results, allowing us to spatially resolve the recrystallization dynamics within the memory cell. It is then demonstrated that this unique approach to photonic memory enables both data storage with tunable volatility and detection of coincident events between two pulse trains on an integrated chip. Finally, improved efficiency and all-optical routing with controlled volatility are demonstrated in a ring resonator. These crucial results show that volatility is intrinsically tunable in normally nonvolatile GST which can be used in both regimes interchangeably.Engineering and Physical Sciences Research Council (EPSRC)European CommissionEuropean Research Council (ERC)Deutsche Forschungsgemeinschaf
Uptake and toxicity studies of poly-acrylic acid functionalized silicon nanoparticles in cultured mammalian cells

Poly-acrylic acid (PAAc) terminated silicon nanoparticles (SiNPs) have been synthesized and employed as a synchronous fluorescent signal indicator in a series of cultured mammalian cells: HHL5, HepG2 and 3T3-L1. Their biological effects on cell growth and proliferation in both human and mouse cell lines have been studied. There was no evidence of in vitro cytotoxity in the cells exposed to PAAc terminated SiNPS when assessed by cell morphology, cell proliferation and viability, and DNA damage assays. The uptake of the nanocrystals by both HepG2 and 3T3-L1 cells was investigated by confocal microscopy and flow cytometry, which showed a clear time-dependence at higher concentrations. Reconstructed 3-D confocal microscope images exhibited that the PAAc-SiNPs were evenly distributed throughout the cytosol rather than attached to outer membrane. This study provides fundamental evidence for the safe application and further modification of silicon nanoparticles, which could broaden their application as cell markers in living systems and in micelle encapsulated drug delivery systems
Fabrication of a Hybrid Microfluidic System Incorporating both Lithographically Patterned Microchannels and a 3D Fiber-Formed Microfluidic Network

A device containing a 3D microchannel network (fabricated using sacrificial melt-spun microfibers) sandwiched between lithographically patterned microfluidic channels offers improved delivery of soluble compounds to a large volume compared to a simple stack of two microfluidic channel layers. With this improved delivery ability comes an increased fluidic resistance due to the tortuous network of small-diameter channels.United States. Army (Engineer Research and Development Center-Construction Engineering Research Laboratory (ERDC-CERL))National Institutes of Health (U.S.) (NIH grant 5F32EB011866)National Institutes of Health (U.S.) (NIH Grant 1K99EB013630)National Institutes of Health (U.S.) (NIH NHLBI grant 1 R21  HL106585-01)National Heart, Lung, and Blood Institute (NIH NHLBI grant 1 R21 HL106585-01
Materials for Diabetes Therapeutics

This review is focused on the materials and methods used to fabricate closed-loop systems for type 1 diabetes therapy. Herein, we give a brief overview of current methods used for patient care and discuss two types of possible treatments and the materials used for these therapies–(i) artificial pancreases, comprised of insulin producing cells embedded in a polymeric biomaterial, and (ii) totally synthetic pancreases formulated by integrating continuous glucose monitors with controlled insulin release through degradable polymers and glucose-responsive polymer systems. Both the artificial and the completely synthetic pancreas have two major design requirements: the device must be both biocompatible and be permeable to small molecules and proteins, such as insulin. Several polymers and fabrication methods of artificial pancreases are discussed: microencapsulation, conformal coatings, and planar sheets. We also review the two components of a completely synthetic pancreas. Several types of glucose sensing systems (including materials used for electrochemical, optical, and chemical sensing platforms) are discussed, in addition to various polymer-based release systems (including ethylene-vinyl acetate, polyanhydrides, and phenylboronic acid containing hydrogels).Juvenile Diabetes Research Foundation International (17-2007-1063)Leona M. and Harry B. Helmsley Charitable Trust (09PG-T1D027)United States. National Institutes of Health (F32 EB011580-01
Image-Predicated Sorting of Adherent Cells Using Photopatterned Hydrogels

Using photopatterned hydrogels and selective cell encapsulation, populations of adherent cells are examined using microscopy and sorted into viable sub-populations predicated on their imaged phenotypes. The inexpensive method utilizes commercial reagents and equipment available in many labs, making image-predicated cell sorting an accessible technique for a large number of individual labs.National Institutes of Health (U.S.) (RR19652)Singapore-MIT AllianceNational Science Foundation (U.S.). Graduate Research FellowshipUnited States. Dept. of Defense (Graduate Fellowship
In vitro biocompatibility of multiwalled carbon nanotubes with sensory neurons

Multiwalled carbon nanotubes (MWCNTs) possess unique properties rendering them a potentially useful biomaterial for neurobiological applications such as providing nanoscale contact-guidance cues for directing axon growth within peripheral nerve repair scaffolds. The in vitro biocompatibility of MWCNTs with postnatal mouse spinal sensory neurons was assessed for this application. Cell culture medium conditioned with MWCNTs was not significantly toxic to dissociated cultures of postnatal mouse dorsal root ganglia (DRG) neurons. However, exposure of DRG neurons to MWCNTs dispersed in culture medium resulted in a time- and dose-dependent reduction in neuronal viability. At 250 :g mL−1, dispersed MWCNTs caused significant neuronal death and unusual neurite morphologies illustrated by immunofluorescent labelling of the cytoskeletal protein beta (III) tubulin, however, at a dose of 5 :g mL−1 MWCNTs were nontoxic over a 14-day period. DRG neurons grown on fabricated MWCNT substrates produced neurite outgrowths with abnormal morphologies that were significantly inferior in length to neurons grown on the control substrate laminin. This evidence demonstrates that to be utilized as a biomaterial in tissue scaffolds for nerve repair, MWCNTs will require robust surface modification to enhance biocompatibility and growth promoting propertie
Biocompatibility evaluation of ionic- and photo-crosslinked methacrylated gellan gum hydrogels: in vitro and In vivo study

In this study, the stability and biocompatibility of methacrylated gellan gum
hydrogels, obtained either by ionic- (iGG-MA) or photo-crosslinking (phGGMA),
were evaluated in vitro and in vivo. Size exclusion chromatography
analysis of the methacrylated gellan gum (GG-MA) powder revealed that
molecular weight is lower as compared to the non-modifi ed material, i.e.,
low acyl gellan gum. The water uptake and swelling of iGG-MA and phGGMA
hydrogels were investigated in phosphate-buffered saline solution (pH
7.4). The biocompatibility of the hydrogels was fi rstly evaluated by producing
cell-laden hydrogels. The in vitro cells encapsulation study showed that lung
fi broblast cells (L929 cells) and human intervertebral disc (hIVD) cells are
viable when cultured within both hydrogels, up to 21 days of culturing. The
iGG-MA and phGG-MA hydrogels were also subcutaneously implanted in
Lewis rats for 10 and 18 days. Tissue response to the hydrogels implantation
was determined by histological analysis (haematoxylin-eosin staining). A thin
fi brous capsule was observed around the implanted hydrogels. No necrosis,
calcifi cation, and acute infl ammatory reaction were observed. The results presented
in this study demonstrate that iGG-MA and phGG-MA hydrogels are
stable in vitro and in vivo, support L929 and hIVD cells’ encapsulation and
viability, and were found to be well-tolerated and non-toxic in vivo.The authors thank the funds provided by Portuguese Foundation for Science and Technology (FCT) through POCTI and FEDER programmes. This work was also supported by the European Union funded Collaborative Project Disc Regeneration (NMP3-LA-2008-213904)
Photocrosslinkable Kappa-carrageenan hydrogels for tissue engineering applications

Published onlineKappa carrageenan ( κ -CA) is a natural-origin polymer that closely mimics
the glycosaminoglycan structure, one of the most important constituents of
native tissues extracellular matrix. Previously, it has been shown that κ -CA
can crosslink via ionic interactions rendering strong, but brittle hydrogels.
In this study, we introduce photocrosslinkable methacrylate moieties on the
κ -CA backbone to create physically and chemically crosslinked hydrogels
highlighting their use in the context of tissue engineering. By varying the
degree of methacrylation, the effect on hydrogel crosslinking was investigated
in terms of hydration degree, dissolution profi les, morphological,
mechanical, and rheological properties. Furthermore, the viability of fi broblast
cells cultured inside the photocrosslinked hydrogels was investigated. The
combination of chemical and physical crosslinking procedures enables the
formation of hydrogels with highly versatile physical and chemical properties,
while maintaining the viability of encapsulated cells. To our best knowledge,
this is the fi rst study reporting the synthesis of photocrosslinkable κ -CA with
controllable compressive moduli, swelling ratios and pore size distributions.
Moreover, by micromolding approaches, spatially controlled geometries and
cell distribution patterns could be obtained, thus enabling the development
of cell-material platforms that can be applied and tailored to a broad range of
tissue engineering strategies.Authors thank Dr. Alpesh Patel, Dr. Shilpa Sant and Hyeongho Shin for valuable scientific discussions. SMM thanks the Portuguese Foundation for Science and Technology (FCT) for the personal grant SFRH/BD/42968/2008 (MIT-Portugal Program) and the financial support of MIT/ECE/0047/2009 project. AKG would like to thank Prof. Robert Langer (MIT) and MIT-Portugal Program for the financial support. Author Contributions : S. M. M., A. G., and A. K. designed the study; S. M. M. synthesized the MA-kappa-CA, produced the hydrogels, and performed the cells studies, swelling and degradation studies. S.M.M. and A.G. performed the rest of the experimental part; S.M.M., A.G. and A.K. wrote the paper. A.P.M., R.L.R., and M.E.G. revised the paper. All authors discussed the results and commented on the manuscript
Extracellular Matrix Heterogeneity Regulates Three-Dimensional Morphologies of Breast Adenocarcinoma Cell Invasion

Plasticity and reciprocity of breast cancer cells to various extracellular matrice (ECMs) are three-dimensionally analyzed in quantitative way in a novel and powerful microfluidic in vitro platform. This successfully demonstrates the metastatic potential of cancer cells and their effective strategies of ECM proteolytic remodeling and morphological change, while interacting with other cells and invading into heterogeneous ECMs.International Research & Development Program (Grant 2009-00631)National Research Foundation of Korea (Basic Science Research Program Grant 2012-022481
Core-Shell Hydrogel Microcapsules for Improved Islets Encapsulation

Islets microencapsulation holds great promise to treat type 1 diabetes. Currently used alginate microcapsules often have islets protruding outside capsules, leading to inadequate immuno-protection. A novel design of microcapsules with core–shell structures using a two-fluid co-axial electro-jetting is reported. Improved encapsulation and diabetes correction is achieved in a single step by simply confining the islets in the core region of the capsules.Juvenile Diabetes Research Foundation International (grant 17-2007-1063)National Institutes of Health (U.S.) (Postdoctoral Fellowship F32 EB011580- 01)Tayebati Family Foundatio
Surface‐Micromachined Microfiltration Membranes for Efficient Isolation and Functional Immunophenotyping of Subpopulations of Immune Cells

An accurate measurement of the immune status in patients with immune system disorders is critical in evaluating the stage of diseases and tailoring drug treatments. The functional cellular immunity test is a promising method to establish the diagnosis of immune dysfunctions. The conventional functional cellular immunity test involves measurements of the capacity of peripheral blood mononuclear cells to produce pro‐inflammatory cytokines when stimulated ex vivo. However, this “bulk” assay measures the overall reactivity of a population of lymphocytes and monocytes, making it difficult to pinpoint the phenotype or real identity of the reactive immune cells involved. In this research, we develop a large surface micromachined poly‐dimethylsiloxane (PDMS) microfiltration membrane (PMM) with high porosity, which is integrated in a microfluidic microfiltration platform. Using the PMM with functionalized microbeads conjugated with antibodies against specific cell surface proteins, we demonstrated rapid, efficient and high‐throughput on‐chip isolation, enrichment, and stimulation of subpopulations of immune cells from blood specimens. Furthermore, the PMM‐integrated microfiltration platform, coupled with a no‐wash homogeneous chemiluminescence assay (“AlphaLISA”), enables us to demonstrate rapid and sensitive on‐chip immunophenotyping assays for subpopulations of immune cells isolated directly from minute quantities of blood samples.     An integrated microfluidic microfiltration platform  containing a unique surface micromachined poly‐dimethylsiloxane (PDMS) microfiltration membrane (PMM) and microbeads conjugated with antibodies is reported for rapid, efficient and high‐throughput on‐chip isolation, enrichment, and stimulation of subpopulations of immune cells from blood specimens. Furthermore, the PMM‐integrated microfiltration platform, coupled with a no‐wash homogeneous chemiluminescence assay (“AlphaLISA”), allows rapid and sensitive on‐chip immunophenotyping assays for subpopulations of immune cells isolated directly from minute quantities of blood samples