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Colin K Curtis, Antonin Marek, Alex I Smirnov, Jacqueline Krim
This article reports a comparative study of the nanoscale and macroscale tribological attributes of alumina and stainless steel surfaces immersed in aqueous suspensions of positively (hydroxylated) or negatively (carboxylated) charged nanodiamonds (ND). Immersion in -ND suspensions resulted in a decrease in the macroscopic friction coefficients to values in the range 0.05-0.1 for both stainless steel and alumina, while +ND suspensions yielded an increase in friction for stainless steel contacts but little to no increase for alumina contacts...
2017: Beilstein Journal of Nanotechnology
Rik van Bremen, Qirong Yao, Soumya Banerjee, Deniz Cakir, Nuri Oncel, Harold J W Zandvliet
We report a combined experimental and theoretical study of the growth of sub-monolayer amounts of silicon (Si) on molybdenum disulfide (MoS2). At room temperature and low deposition rates we have found compelling evidence that the deposited Si atoms intercalate between the MoS2 layers. Our evidence relies on several experimental observations: (1) Upon the deposition of Si on pristine MoS2 the morphology of the surface transforms from a smooth surface to a hill-and-valley surface. The lattice constant of the hill-and-valley structure amounts to 3...
2017: Beilstein Journal of Nanotechnology
Catalina Pimiento, John N Griffin, Christopher F Clements, Daniele Silvestro, Sara Varela, Mark D Uhen, Carlos Jaramillo
The end of the Pliocene marked the beginning of a period of great climatic variability and sea-level oscillations. Here, based on a new analysis of the fossil record, we identify a previously unrecognized extinction event among marine megafauna (mammals, seabirds, turtles and sharks) during this time, with extinction rates three times higher than in the rest of the Cenozoic, and with 36% of Pliocene genera failing to survive into the Pleistocene. To gauge the potential consequences of this event for ecosystem functioning, we evaluate its impacts on functional diversity, focusing on the 86% of the megafauna genera that are associated with coastal habitats...
August 2017: Nature ecology & evolution
Michio Nakamura, Tadashi Miyazaki, Natsuki Shinozaki, Masaki Izumi, Takashi Itabashi
OBJECTIVE: Craniocervical junction arteriovenous fistulas(CCJ-AVFs)are extremely rare lesions that may result in both subarachnoid hemorrhage(SAH)and myelopathy. Diagnosis of CCJ-AVF is difficult and may be delayed due to variable clinical features and a spectrum of neuroradiological findings. To elucidate the clinical characteristics of CCJ-AVF, we analyzed the clinical symptoms, neuroimaging findings, and the results of surgical treatment in five patients. RESULTS: Among the five patients, four were diagnosed with dural AVFs, and the remaining patient was diagnosed with radicular AVF...
October 2017: No Shinkei Geka. Neurological Surgery
Christopher Stryker, Dominic W Camperchioli, Catherine A Mayer, Warren J Alilain, Richard John Martin, Peter M MacFarlane
The extracellular matrix (ECM) modulates brain maturation and plays a major role in regulating neuronal plasticity during critical periods of development. We examined: 1) whether there is a critical postnatal period of ECM expression in brainstem cardio-respiratory control regions; and 2) if the attenuated hypoxic ventilatory response (HVR) following neonatal sustained (5 days) hypoxia exposure (SH, 11% O2, 24hrs/day) is associated with altered ECM formation. The nucleus tractus solitarius (nTS), dorsal motor nucleus of the vagus (DMNV), the hypoglossal motor nucleus (XII), the cuneate nucleus (CN) and area postrema (AP) were immunofluorescently processed for aggrecan and Wisteria floribunda (WFA) agglutinin, a key proteoglycan of the ECM and the perineuronal net...
October 18, 2017: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
Anne-Laure Faucon, Guillaume Bobrie, Anne-Sophie Jannot, Arshid Azarine, Pierre-François Plouin, Michel Azizi, Laurence Amar
BACKGROUND: Renal infarction can cause abrupt and severe hypertension and less frequently renal failure. Renal infarction results from disruption of renal blood flow in the main ipsilateral renal artery or in a segmental branch. Underlying mechanism is either general, 'embolic' or 'thrombophilic', or local related to primary 'renal artery lesion'. It depends on various causes. In absence of an identified cause, renal infarction is classified as 'idiopathic'. Previous studies report a significant number of 'idiopathic' renal infarction...
October 16, 2017: Journal of Hypertension
Sang-Kwon Lee, Kyoung-Oh Cho, Mia Madel Alfajaro, Juhwan Lee, Dohyeon Yu, Jihye Choi
A 10-year-old female spayed Dachshund was referred with progressive coughing for 1 month. The dog was tentatively diagnosed with right middle lung torsion based on pleural effusion, vesicular emphysema, abruptly ending bronchus in consolidated right middle lung, and no contrast enhancement of the affected lobe on radiography and computed tomography (CT). There was no evidence of torsion upon thoracotomy, and histological examination confirmed lobar pneumonia. The CT images were reevaluated using minimum intensity projection and revealed normal bronchial courses...
October 16, 2017: Veterinary Radiology & Ultrasound
Fu-Ling Liu, Jun Tao
The reaction of ferrous salts and square planar tetracyanometallates [MII(CN)4]2- (M = Pd, Pt) with ligand 4-(1H-pyrazol-3-yl)pyridine (Hppy) resulted in the formation of two two-dimensional (2D) Hofmann-like coordination polymers (CPs) with general formula of {FeII(Hppy)2[MII(CN)4]}·H2O (M = Pd for 1Pd, Pt for 1Pt). The two CPs have been studied by variable-temperature single-crystal X-ray crystallography, differential scanning calorimetry and magnetic measurements, respectively. 1Pd and 1Pt are isostructures, in which the Fe(II) atoms are equatorially coordinated with [MII(CN)4]2- to form 2D undulating layer and axially coordinated with Hppy ligands...
October 18, 2017: Chemistry: a European Journal
Ji-Qing Qiu, Yu Cui, Li-Chao Sun, Zhan-Peng Zhu
Aphasia is a common symptom encountered by neurologists. However, the presence of aphasia as the sole manifestation of partial status epilepticus is rare. The present study reports a case of aphasic status epilepticus in a 27-year-old right-handed female who presented after the abrupt onset of aphasia, which had persisted for 1.5 days. The patient's medical history included head trauma followed by a craniectomy and cranioplasty. Computed tomography scans revealed a lesion in the patient's left parietal lobe, and an electroencephalogram showed a spike and slow wave pattern in the left hemisphere of the brain during aphasia...
October 2017: Experimental and Therapeutic Medicine
Joseph G Manning, Francis Ludlow, Alexander R Stine, William R Boos, Michael Sigl, Jennifer R Marlon
Volcanic eruptions provide tests of human and natural system sensitivity to abrupt shocks because their repeated occurrence allows the identification of systematic relationships in the presence of random variability. Here we show a suppression of Nile summer flooding via the radiative and dynamical impacts of explosive volcanism on the African monsoon, using climate model output, ice-core-based volcanic forcing data, Nilometer measurements, and ancient Egyptian writings. We then examine the response of Ptolemaic Egypt (305-30 BCE), one of the best-documented ancient superpowers, to volcanically induced Nile suppression...
October 17, 2017: Nature Communications
Atsuhiro Adachi, Michiko Koizumi, Yoshinori Ohsumi
Autophagy is a conserved process in which cytoplasmic components are sequestered for degradation in the vacuole/lysosomes in eukaryotic cells. Autophagy is induced under a variety of starvation conditions, such as the depletion of nitrogen, carbon, phosphorus, zinc and others. However, apart from nitrogen starvation, it remains unclear how these stimuli induce autophagy. In yeast, for example, it remains contentious whether autophagy is induced under carbon starvation conditions, with reports variously suggesting both induction and lack of induction upon depletion of carbon...
October 17, 2017: Journal of Biological Chemistry
Chao Pan, Xiaorui Liu, Hui Zhu, Xuekang Shan, Xiaohan Sun
A real-time distributed optical fiber vibration sensing prototype based on the Sagnac interference in conjunction with the optical time domain reflectometry (OTDR) was developed. The sensing mechanism for single- and multi-points vibrations along the sensing fiber was analyzed theoretically and demonstrated experimentally. The experimental results show excellent agreement with the theoretical models. It is verified that single-point vibration induces a significantly abrupt and monotonous power change in the corresponding position of OTDR trace...
August 21, 2017: Optics Express
Zhuo Yang, Deng-Feng Kuang, Fang Cheng
We present a dolphin-shaped cell meta-surface, which is a combination of dolphin-shaped metallic cells and dielectric substrate, for vector vortex beam generation with the illumination of linearly polarized light. Surface plasmon polaritons are excited at the boundary of the metallic cells, then guided by the metallic structures, and finally squeezed to the tips to form highly localized strong electromagnetic fields, which generate the intensity of vector vortex beams at z component. Synchronously, the abrupt phase change produced by the meta-surface is utilized to explain the vortex phase generated by elements...
September 18, 2017: Optics Express
Brian M Cullum, Ellen L Holthoff, Paul M Pellegrino
Control and manipulation of sound is of critical importance to many different scientific and engineering fields, requiring the design of rigid physical structures with precise geometries and material properties for the desired acoustics. In this work, we demonstrate the ability to manipulate the direction and magnitude of sound waves traveling in air using laser light, without the need for physical interfaces associated with different materials. Efficient reflection of sound waves off of transient, optically generated, abrupt air density barriers is demonstrated, with acoustic reflections greater than 25% of the incident acoustic wave amplitude...
September 18, 2017: Optics Express
Sen Wang, Xinke Wang, Yan Zhang
Based on the amplitude and phase modulation of subwavelength slits, a metasurface which can simultaneously generate Airy beam for surface plasmon polaritons (SPPs) and transmitted wave is presented. Interestingly, by changing the handedness of circularly polarized light, the position of SPPs Airy beam can be switched to the left or right side of the metasurface, while the field distribution and the position of the Airy beam for transmitted wave are not affected. The nondiffracting, self-bending and self-healing properties of the generated Airy beams are analyzed as well...
October 2, 2017: Optics Express
K E Roberts, S F Lamoureux, T K Kyser, D C G Muir, M J Lafrenière, D Iqaluk, A J Pieńkowski, A Normandeau
Permafrost exerts an important control over hydrological processes in Arctic landscapes and lakes. Recent warming and summer precipitation has the potential to alter water availability and quality in this environment through thermal perturbation of near surface permafrost and increased mobility of previously frozen solutes to Arctic freshwaters. We present a unique thirteen-year record (2003-16) of the physiochemical properties of two High Arctic lakes and show that the concentration of major ions, especially SO4(2-), has rapidly increased up to 500% since 2008...
October 16, 2017: Scientific Reports
Rong Jin, Adam Y Xiao, Zifang Song, Shiyong Yu, Jarvis Li, Mei-Zhen Cui, Guohong Li
The role of platelets in the development of thrombosis and abrupt closure after angioplasty is well recognized. However, the direct impact of platelets on neointima formation after arterial injury remains undetermined. Here we show that neointima formation after carotid artery wire injury reduces markedly in CD40(-/-)apoE(-/-) mice but only slightly in CD40L(-/-)apoE(-/-) mice, compared with apolipoprotein E-deficient (apoE(-/-)) mice. Wild-type and CD40-deficient platelets were isolated from blood of apoE(-/-) and CD40(-/-)apoE(-/-) mice, respectively...
October 13, 2017: American Journal of Pathology
Tong Li, Fei Zi, Kaikai Huang, Xuanhui Lu
We propose a multifocus autofocusing Airy beam (MAAB) by modifying the frequency spectrum of a symmetric Airy beam (SAB) with a Gaussian band elimination filter. Unlike the original SAB, there are four off-axis foci at the autofocusing plane of the MAAB. The MAAB has a better abruptly autofocusing property than the original SAB. In addition, with the increase of the normalized intensity at the first peak, the focal position (second peak) of the MAAB remains almost the same, whereas the position of the first peak shifts along the propagation direction gradually...
September 1, 2017: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Cristian E Gutiérrez, Luca Pallucchini, Eric Stachura
This paper provides a mathematical approach to study metasurfaces in nonflat geometries. Analytical conditions between the curvature of the surface and the set of refracted directions are introduced to guarantee the existence of phase discontinuities. The approach contains both the near and far field cases. A starting point is the formulation of a vector Snell's law in the presence of abrupt discontinuities on the interfaces.
July 1, 2017: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Rafael R da Silva, Sandro V de Lima, Helinando P de Oliveira, Celso P de Melo, Isaac A M Frías, Maria D L Oliveira, César A S Andrade
Electrical impedance spectroscopy (EIS) appears a promising label-free methodology for the investigation of processes related to the aggregation of macromolecules in solution. Here, we explore the EIS technique as a convenient tool for studying the irreversible aggregation of human insulin and describing its corresponding fibrillation kinetics. The in situ measurement of the electrical response of pure insulin solutions at 60°C allows for the real-time monitoring of the protein fibrillation as a function of the incubation time...
October 7, 2017: Colloids and Surfaces. B, Biointerfaces
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