bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Two‐Step K‐Ar Experiment on Mars: Dating the Diagenetic Formation of Jarosite from Amazonian Groundwaters
Authors: Martin P. E. , Farley K. A. , Baker M. B. , Malespin C. A. , Schwenzer S. P. , Cohen B. A. , Mahaffy P. R. , McAdam A. C. , Ming D. W. , Vasconcelos P. M. , Navarro‐González R. 
Published: December 2017

AbstractFollowing K‐Ar dating of a mudstone and a sandstone, a third sample has been dated by the Curiosity rover exploring Gale Crater. The Mojave 2 mudstone, which contains relatively abundant jarosite, yielded a young K‐Ar bulk age of 2.57 ± 0.39 Ga (1σ precision). A two‐step heating experiment was implemented in an effort to resolve the K‐Ar ages of primary and secondary mineralogical components within the sample. This technique involves measurement of 40Ar released in low‐temperature (500°C) and high‐temperature (930°C) steps, and a model of the potassium distribution within the mineralogical components of the sample. Using this method, the high‐temperature step yields a K‐Ar model age of 4.07 ± 0.63 Ga associated with detrital plagioclase, compatible with the age obtained on the Cumberland mudstone by Curiosity. The low‐temperature step, associated with jarosite mixed with K‐bearing evaporites and/or phyllosilicates, gave a youthful K‐Ar model age of 2.12 ± 0.36 Ga. The interpretation of this result is complicated by the potential for argon loss after mineral formation. Comparison with the results on Cumberland and previously published constraints on argon retentivity of the individual phases likely to be present suggests that the formation age of the secondary materials, correcting for plausible extents of argon loss, is still less than 3 Ga, suggesting post‐3 Ga aqueous processes occurred in the sediments in Gale Crater. Such a result is inconsistent with K‐bearing mineral formation in Gale Lake and instead suggests postdepositional fluid flow at a time after surface fluvial activity on Mars is thought to have largely ceased.
Linkages Among Climate, Fire, and Thermoerosion in Alaskan Tundra Over the Past Three Millennia
Authors: Chipman M. L. , Hu F. S. 
Published: December 2017

AbstractAmplified Arctic warming may facilitate novel tundra disturbance regimes, as suggested by recent increases in the rate and extent of thermoerosion and fires in some tundra areas. Thermoerosion and wildfire can exacerbate warming by releasing large permafrost carbon stocks, and interactions between disturbance regimes can lead to complex ecosystem feedbacks. We conducted geochemical and charcoal analyses of lake sediments from an Alaskan lake to identify thermoerosion and fire events over the past 3,000 years. Thermoerosion was inferred from lake sediments in the context of modern soil data from retrogressive thaw slumps (RTS). Magnetic susceptibility (MS), Ca:K, and Ca:Sr increased with depth in modern RTS soils and were higher on recently exposed than older slump surfaces. Peaks in bulk density, % CaCO3, Ca:K, Ca:Sr, and MS values in the sediments suggest at least 18 thermoerosion events in the Loon Lake watershed over the past 3,000 years. Charcoal analysis identifies 22 fires over the same period at this site. Temporal variability in these records suggests climate‐driven responses of both thermoerosion and fire disturbance regimes, with fewer RTS episodes and fire events during the Little Ice Age than the Medieval Climate Anomaly. Moreover, RTS activity lagged behind catchment fires by 20–30 years (>90% confidence interval), implying that fires facilitated thermoerosion on decadal time scales, possibly because of prolonged active‐layer deepening following fire and postfire proliferation of insulative shrub cover. These results highlight the potential for complex interactions between climate, vegetation, and tundra disturbance in response to ongoing warming.
Effects of Drought Manipulation on Soil Nitrogen Cycling: A Meta‐Analysis
Authors: Homyak Peter M. , Allison Steven D. , Huxman Travis E. , Goulden Michael L. , Treseder Kathleen K. 
Published: December 2017

AbstractMany regions on Earth are expected to become drier with climate change, which may impact nitrogen (N) cycling rates and availability. We used a meta‐analytical approach on the results of field experiments that reduced precipitation and measured N supply (i.e., indices of N mineralization), soil microbial biomass, inorganic N pools (ammonium (NH4+) and nitrate (NO3−)), and nitrous oxide (N2O) emissions. We hypothesized that N supply and N2O emissions would be relatively insensitive to precipitation reduction and that reducing precipitation would increase extractable NH4+ and NO3− concentrations because microbial processes continue, whereas plant N uptake diminishes with drought. In support of this hypothesis, extractable NH4+ increased by 25% overall with precipitation reduction; NH4+ also increased significantly with increasing magnitude of precipitation reduction. In contrast, N supply and extractable NO3− did not change and N2O emissions decreased with reduced precipitation. Across studies microbial biomass appeared unchanged, yet from the diversity of studies, it was clear that proportionally smaller precipitation reductions increased microbial biomass, whereas larger proportional reductions in rainfall reduced microbial biomass; there was a positive intercept (P = 0.005) and a significant negative slope (P = 0.0002) for the regression of microbial biomass versus % precipitation reduction (LnR = −0.009 × (% precipitation reduction) + 0.4021). Our analyses imply that relative to other N variables, N supply is less sensitive to reduced precipitation, whereas processes producing N2O decline. Drought intensity and duration, through sustained N supply, may control how much N becomes vulnerable to loss via hydrologic and gaseous pathways upon rewetting dry soils.
COMP report: CPQR technical quality control guideline for medical linear accelerators and multileaf collimators
Authors: Kirkby Charles , Ghasroddashti Esmaeel , Angers Crystal Plume , Zeng Grace , Barnett Erin 
Published: December 2017

AbstractThe Canadian Organization of Medical Physicists (COMP), in close partnership with the Canadian Partnership for Quality Radiotherapy (CPQR) has developed a series of Technical Quality Control (TQC) guidelines for radiation treatment equipment. These guidelines outline the performance objectives that equipment should meet in order to ensure an acceptable level of radiation treatment quality. The TQC guidelines have been rigorously reviewed and field tested in a variety of Canadian radiation treatment facilities. The development process enables rapid review and update to keep the guidelines current with changes in technology (the most updated version of this guideline can be found on the CPQR website). This particular TQC details recommended quality control testing for medical linear accelerators and multileaf collimators.
Xeroderma pigmentosum is a definite cause of Huntington's disease‐like syndrome
Authors: Garcia‐Moreno Hector , Fassihi Hiva , Sarkany Robert P.E. , Phukan Julie , Warner Thomas , Lehmann Alan R. , Giunti Paola 
Published: December 2017

AbstractXeroderma pigmentosum is characterized by cutaneous, ophthalmological, and neurological features. Although it is typical of childhood, late presentations can mimic different neurodegenerative conditions. We report two families presenting as Huntington's disease‐like syndromes. The first case (group G) presented with neuropsychiatric features, cognitive decline and chorea. Typical lentigines were only noticed after the neurological disease started. The second case (group B) presented adult‐onset chorea and neuropsychiatric symptoms after an aggressive ocular melanoma. Xeroderma pigmentosum can manifest as a Huntington's Disease‐like syndrome. Classic dermatological and oncological features have to be investigated in choreic patients with negative genetic tests for Huntington's disease‐like phenotypes.
Neurospheres on Patterned PEDOT:PSS Microelectrode Arrays Enhance Electrophysiology Recordings
Authors: Pas Jolien , Pitsalidis Charalampos , Koutsouras Dimitrios A. , Quilichini Pascale P. , Santoro Francesca , Cui Bianxiao , Gallais Laurent , O'Connor Rodney P. , Malliaras George G. , Owens Róisín M. 
Published: December 2017

AbstractMicroelectrode arrays (MEAs) are a versatile diagnostic tool to study neural networks. Culture of primary neurons on these platforms allows for extracellular recordings of action potentials. Despite many advances made in the technology to improve such recordings, the recording yield on MEAs remains sparse. Here, enhanced recording yield is shown induced by varying cell densities on poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate)‐coated MEAs. It is demonstrated that high cell densities (900 cells mm−2) of primary cortical cells increase the number of recording electrodes by 53.1% ± 11.3%, compared with low cell densities (500 cells mm−2) with 6.3% ± 1.4%. To further improve performance, 3D clusters known as neurospheres are cultured on the MEAs, significantly increasing single unit activity recordings. Extensive spike sorting is performed to analyze the unit activity recording multiple neurons with a single microelectrode. Finally, patterning of polyethylene glycol diacrylate through laser ablation is demonstrated, as a means to more precisely confine neurospheres on top of the electrodes. The possibility of recording single neurons with multiple neighboring electrodes is shown. Overall, a total recording yield of 21.4% is achieved, with more than 90% obtained from electrodes with neurospheres, maximizing the functionality of these planar MEAs as effective tools to study pharmacology‐based effects on neural networks.
Mechanoregulation of Myofibroblast Fate and Cardiac Fibrosis
Authors: Kim Peter , Chu Nick , Davis Jennifer , Kim Deok‐Ho 
Published: December 2017

AbstractDuring myocardial infarction, myocytes die and are replaced by a specialized fibrotic extracellular matrix, otherwise known as scarring. Fibrotic scarring presents a tremendous hemodynamic burden on the heart, as it creates a stiff substrate, which resists diastolic filling. Fibrotic mechanisms result in permanent scarring which often leads to hypertrophy, arrhythmias, and a rapid progression to failure. Despite the deep understanding of fibrosis in other tissues, acquired through previous investigations, the mechanisms of cardiac fibrosis remain unclear. Recent studies suggest that biochemical cues as well as mechanical cues regulate cells in myocardium. However, the steps in myofibroblast transdifferentiation, as well as the molecular mechanisms of such transdifferentiation in vivo, are poorly understood. This review is focused on defining myofibroblast physiology, scar mechanics, and examining current findings of myofibroblast regulation by mechanical stress, stiffness, and topography for understanding fibrotic disease dynamics.
The Neuroinflammatory Response to Nanopatterning Parallel Grooves into the Surface Structure of Intracortical Microelectrodes
Authors: Ereifej Evon S. , Smith Cara S. , Meade Seth M. , Chen Keying , Feng He , Capadona Jeffrey R. 
Published: December 2017

AbstractThe smooth surface structure of intracortical microelectrodes implanted within the nanometer‐scale architecture of brain tissue may contribute to the foreign body response. Here, the neuroinflammatory response to nanopatterning surface grooves etched directly on nonfunctional Michigan‐style microelectrodes is explored. Rats implanted with nanopatterned silicon microelectrodes are compared to smooth control implants to observe the effects the grooves have on neuroinflammation. Histology and real‐time PCR at 2 and 4 weeks postimplantation quantify glial cell reactivity and activation, inflammation, oxidative stress, and neuronal survival. Histological observations of glial cells and blood–brain barrier permeability do not show appreciable differences between the nanopatterned and control implants. However, silicon microelectrodes with nanopatterned grooves have more high mobility group box 1 (HMGB1) gene expression at 2 weeks and less nitric oxide synthase (NOS2) gene expression at 4 weeks compared to control surfaces. Control samples have increased NOS2, HMGB1, and tumor necrosis factor gene expression from 2 to 4 weeks, while nanopatterned implants have significant decrease in CD14 gene expression from 2 to 4 weeks. Collectively the results indicate that etching nanopatterned grooves do not reduce histological markers of neuroinflammation compared to control implants, but gene expression results encourage further investigation.
Ultrafast Nanoscale Polymer Coating on Porous 3D Structures Using Microwave Irradiation
Authors: Choi Woongchul , Choi Kyungwho , Yu Choongho 
Published: December 2017

AbstractThin polymer coatings are very popular, but the coatings on uneven surfaces or porous 3D structures are difficult to obtain with traditional methods. The pores are easily clogged due to nonuniform polymer curing processes caused by inevitable macroscale temperature gradients from their hotter outer to colder inner sides. Here an ultrafast and simple fabrication method is developed to obtain nanoscale coating layers on the inner and outer surfaces of a porous 3D sponge‐like carbon nanotube (CNT). Microwave irradiation rapidly and selectively heats the CNT immersed in a mixture solution of an uncured polymer and a diluent solvent, solidifying the polymer only adjacent to the CNT with five repeated 3 s microwave irradiation. The coating layers can be controlled by adjusting the concentration of the uncured polymer in the solution and controlling the CNT temperature via microwave power and irradiation time. The nanoscale coating strongly ties the junction between CNTs without filling the pores with the polymer, resulting in excellent resilience to compressive stress with large strains (≈180 kPa at 60%), which is maintained throughout repeated 8000 cycles of 0–60% strain. The unfilled pores allow for maintaining the low thermal conductivity, ≈26 mW m−1 K−1, and the electrical resistance is varied with strain. This facile selective polymer curing methodology can be utilized in processing various materials with uneven surfaces or pores.
Hofmeister Effect‐Assisted One Step Fabrication of Ductile and Strong Gelatin Hydrogels
Authors: He Qingyan , Huang Yan , Wang Shaoyun 
Published: December 2017

AbstractHydrogels with high strength and ductility are normally prepared from synthetic polymers, and most protein‐based hydrogels are soft and brittle. Here, a strong, ductile gelatin hydrogel is prepared by simply soaking a virgin gelatin gel in an ammonium sulfate solution. The polymer chains in the covalent, crosslink‐free network can freely move to homogeneously distribute stress, and more importantly, the highly kosmotropic ammonium sulfate ions greatly enhance the hydrophobic interactions and chain bundling within the gelatin gels. As a result, the treated hydrogels have an extraordinary ultimate strength (compressive and tensile strains of over 99% and 500%, respectively, and stresses of 12 and 3 MPa) superior to that of common protein gels. The physical crosslinks introduced by the Hofmeister effect can rapidly absorb energy and sustain large deformations via decrosslinking and dissociation, which result in energy dissipation and antifatigue properties. The effects of the gelatin and (NH4)2SO4 concentrations on the hydrogel mechanics are evaluated, and the possible strengthening mechanism is discussed. The effect of various ions in the Hofmeister series on the gelatin hydrogel is also investigated. Kosmotropic ions enhance the mechanical properties, whereas chaotropic ions soften and dissolve the gel.
Biomimetic Chitin–Silk Hybrids: An Optically Transparent Structural Platform for Wearable Devices and Advanced Electronics
Authors: Hong Moo‐Seok , Choi Gwang‐Mun , Kim Joohee , Jang Jiuk , Choi Byeongwook , Kim Joong‐Kwon , Jeong Seunghwan , Leem Seongmin , Kwon Hee‐Young , Hwang Hyun‐Bin , Im Hyeon‐Gyun , Park Jang‐Ung , Bae Byeong‐Soo , Jin Jungho 
Published: December 2017

AbstractThe cuticles of insects and marine crustaceans are fascinating models for man‐made advanced functional composites. The excellent mechanical properties of these biological structures rest on the exquisite self‐assembly of natural ingredients, such as biominerals, polysaccharides, and proteins. Among them, the two commonly found building blocks in the model biocomposites are chitin nanofibers and silk‐like proteins with β‐sheet structure. Despite being wholly organic, the chitinous protein complex plays a key role for the biocomposites by contributing to the overall mechanical robustness and structural integrity. Moreover, the chitinous protein complex alone without biominerals is optically transparent (e.g., dragonfly wings), thereby making it a brilliant model material system for engineering applications where optical transparency is essentially required. Here, inspired by the chitinous protein complex of arthropods cuticles, an optically transparent biomimetic composite that hybridizes chitin nanofibers and silk fibroin (β‐sheet) is introduced, and its potential as a biocompatible structural platform for emerging wearable devices (e.g., smart contact lenses) and advanced displays (e.g., transparent plastic cover window) is demonstrated.
Advances in Nanoporous Anodic Alumina‐Based Biosensors to Detect Biomarkers of Clinical Significance: A Review
Authors: Rajeev Gayathri , Prieto Simon Beatriz , Marsal Lluis F. , Voelcker Nicolas H. 
Published: December 2017

AbstractThere is a strong and growing demand for compact, portable, rapid, and low‐cost devices to detect biomarkers of interest in clinical and point‐of‐care diagnostics. Such devices aid in early diagnosis of diseases without the need to rely on expensive and time‐consuming large instruments in dedicated laboratories. Over the last decade, numerous biosensors have been developed for detection of a wide range of clinical biomarkers including proteins, nucleic acids, growth factors, and bacterial enzymes. Various transduction techniques have been reported based on biosensor technology that deliver substantial advances in analytical performance, including sensitivity, reproducibility, selectivity, and speed for monitoring a wide range of human health conditions. Nanoporous anodic alumina (NAA) has been used extensively for biosensing applications due to its inherent optical and electrochemical properties, ease of fabrication, large surface area, tunable properties, and high stability in aqueous environment. This review focuses on NAA‐based biosensing systems for detection of clinically significant biomarkers using various detection techniques with the main focus being on electrochemical and optical transduction methods. The review covers an overview of the importance of biosensors for biomarkers detection, general (surface and structural) properties and fabrication of NAA, and NAA‐based biomarker sensing systems.
Recent Progress in Micro/Nanoreactors toward the Creation of Artificial Organelles
Authors: Godoy‐Gallardo Maria , York‐Duran Maria J. , Hosta‐Rigau Leticia 
Published: December 2017

AbstractArtificial organelles created from a bottom up approach are a new type of engineered materials, which are not designed to be living but, instead, to mimic some specific functions inside cells. By doing so, artificial organelles are expected to become a powerful tool in biomedicine. They can act as nanoreactors to convert a prodrug into a drug inside the cells or as carriers encapsulating therapeutic enzymes to replace malfunctioning organelles in pathological conditions. For the design of artificial organelles, several requirements need to be fulfilled: a compartmentalized structure that can encapsulate the synthetic machinery to perform an enzymatic function, as well as a means to allow for communication between the interior of the artificial organelle and the external environment, so that substrates and products can diffuse in and out the carrier allowing for continuous enzymatic reactions. The most recent and exciting advances in architectures that fulfill the aforementioned requirements are featured in this review. Artificial organelles are classified depending on their constituting materials, being lipid and polymer‐based systems the most prominent ones. Finally, special emphasis will be put on the intracellular response of these newly emerging systems.
Iron Oxide Nanoparticles: Innovative Tool in Cancer Diagnosis and Therapy
Authors: Martinkova Pavla , Brtnicky Martin , Kynicky Jindrich , Pohanka Miroslav 
Published: December 2017

AbstractAlthough cancer is one of the most dangerous and the second most lethal disease in the world, current therapy including surgery, chemotherapy, radiotherapy, etc., is highly insufficient not in the view of therapy success rate or the amount of side effects. Accordingly, procedures with better outcomes are highly desirable. Iron oxide nanoparticles (IONPs) present an innovative tool—ideal for innovation and implementation into practice. This review is focused on summarizing some well‐known facts about pharmacokinetics, toxicity, and the types of IONPs, and furthermore, provides a survey of their use in cancer diagnosis and therapy.
Peptide‐Functionalized Polyurethane Coatings Prepared via Grafting‐To Strategy to Selectively Promote Endothelialization
Authors: Ding Xin , Chin Willy , Lee Chuen Neng , Hedrick James L. , Yang Yi Yan 
Published: December 2017

AbstractEndothelialization, formation of endothelial cells (ECs) layer on cardiovascular implant surface, is considered an ideal approach to prevent restenosis (renarrowing of blood vessel mainly due to the accumulation of proliferated vascular smooth muscle cells, SMCs) and thrombosis. In this study, the possibility of using polyurethane (PU) as a coating platform for functionalization with peptide to enhance endothelialization on implants is explored. PUs are synthesized through metal‐free organocatalytic polymerization followed by chemical conjugation with an EC‐specific REDV peptide through thiol–ene reaction. Meanwhile, the free isocyanate groups of PU allow for covalent grafting of REDV‐functionalized PU (PU/REDV) to silanize implant materials (nitinol and PET). PU/REDV coating with peptide grafting density of ≈2 nmol cm−2 selectively accommodates primary human umbilical vein ECs (HUVECs) and retards spreading of primary human umbilical artery SMCs (HUASMCs). In addition, a layer of HUVECs is formed within 3 d on PU/REDV‐coated surfaces, while proliferation of HUASMCs is inhibited. The selectivity is further confirmed by coculture of HUVECs and HUASMCs. Moreover, the PU/REDV‐coated surfaces are less thrombogenic as evidenced by reduced number and activity of adhered platelets. Therefore, PU/REDV can be potentially used as a coating of cardiovascular implants to prevent restenosis and thrombosis by promoting endothelialization.