4,068 results match your criteria will periodic


On-chip terahertz isolator with ultrahigh isolation ratios.

Nat Commun 2021 Sep 22;12(1):5570. Epub 2021 Sep 22.

Wuhan National Laboratory for Optoelectronics and School of Optical and Electronic Information, Huazhong University of Science and Technology, 430074, Wuhan, China.

Terahertz isolators, one of the typical nonreciprocal devices that can break Lorentz reciprocity, are indispensable building blocks in terahertz systems for their critical functionality of manipulating the terahertz flow. Here, we report an integrated terahertz isolator based on the magneto-optical effect of a nonreciprocal resonator. By optimizing the magneto-optical property and the loss of the resonator, we experimentally observe unidirectional propagation with an ultrahigh isolation ratio reaching up to 52 dB and an insertion loss around 7. Read More

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September 2021

Characterization of Morphologic and Cytochemical Staining Properties of Exogenous Materials Mimicking Fungal Organisms Encountered in Skin Biopsies.

Am J Dermatopathol 2021 Oct;43(10):679-687

Associate Professor of Pathology and Dermatology, Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, AR.

Background: Exogenous materials may be encountered in skin biopsies as contamination. Contamination may occur during the biopsy procedure in the clinic or during tissue processing in the laboratory. Although the experienced pathologist may often instinctively ignore clear examples of contamination, such tissue may be a source of confusion for young pathologists and those in training. Read More

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October 2021

Developmental changes and metabolic reprogramming during establishment of infection and progression of Trypanosoma brucei brucei through its insect host.

PLoS Negl Trop Dis 2021 Sep 20;15(9):e0009504. Epub 2021 Sep 20.

Institute of Cell Biology, University of Bern, Bern, Switzerland.

Trypanosoma brucei ssp., unicellular parasites causing human and animal trypanosomiasis, are transmitted between mammals by tsetse flies. Periodic changes in variant surface glycoproteins (VSG), which form the parasite coat in the mammal, allow them to evade the host immune response. Read More

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September 2021

Assessment of thyroid function in the preterm and/or very low birth weight newborn.

An Pediatr (Engl Ed) 2021 Sep 14. Epub 2021 Sep 14.

Sección de Endocrinología Pediátrica, Complejo Hospitalario de Navarra, Pamplona, Navarra, Spain.

The screening program or early detection of congenital hypothyroidism is one of the greatest advances achieved in Pediatrics. Thyroid hormones are essential for brain development and maturation, which continue into the neonatal stage. Alterations in thyroid function in premature and underweight children in the first months of life causes irreversible damage to the central nervous system and is one of the most frequent and avoidable causes of mental retardation. Read More

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September 2021

Electronic structure of the dicationic first row transition metal oxides.

Phys Chem Chem Phys 2021 Sep 16. Epub 2021 Sep 16.

Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849-5312, USA.

Multi-reference electronic structure calculations combined with large basis sets are performed to investigate the electronic structure of the ground and low-lying electronic states of the MO diatomic species with M = Ti-Cu. These systems have shown high efficiency in the activation of the C-H of saturated hydrocarbons. This study is the first systematic and accurate work for these systems and our results and discussion provides insights into the reactivity and stability of MO units. Read More

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September 2021

Non-melanoma Skin Cancers in Patients on Hydroxyurea for Philadelphia Chromosome-Negative Myeloproliferative Neoplasms: A Systematic Review.

Cureus 2021 Aug 7;13(8):e16978. Epub 2021 Aug 7.

Neurology, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA.

Hydroxyurea (HU) or hydroxycarbamide is a cytotoxic antimetabolite widely used to treat Philadelphia chromosome-negative Myeloproliferative Neoplasms (Ph-MPN) like Polycythemia Vera (PV), Essential Thrombocythemia (ET), and Primary Myelofibrosis (PMF). Patients with Ph-MPN are at an increased risk of Non-melanoma skin cancers (NMSC). The cause of this finding remains uncertain. Read More

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Responsive Nanoparticles to Enable a Focused Ultrasound-Stimulated Magnetic Resonance Imaging Spotlight.

ACS Nano 2021 Sep 14. Epub 2021 Sep 14.

California Nano Systems Institute (CNSI), University of California, Los Angeles, California 90095, United States.

Magnetic resonance imaging (MRI)-guided high-intensity focused ultrasound (HIFU) has been applied as a therapeutic tool in the clinic, and enhanced MRI contrast for depiction of target tissues will improve the precision and applicability of HIFU therapy. This work presents a "spotlight MRI" contrast enhancement technique, which combines four essential components: periodic HIFU stimulation, strong modulation of T caused by HIFU, rapid MRI signal collection, and spotlight MRI spectral signal processing. The T modulation is enabled by a HIFU-responsive nanomaterial based on mesoporous silica nanoparticles with Pluronic polymers (Poloxamers) and MRI contrast agents attached. Read More

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September 2021

The necessity of periodic boundary conditions for the accurate calculation of crystalline terahertz spectra.

Phys Chem Chem Phys 2021 Sep 22;23(36):20038-20051. Epub 2021 Sep 22.

Department of Chemistry, University of Vermont, 82 University Place, Burlington, Vermont 05405, USA.

Terahertz vibrational spectroscopy has emerged as a powerful spectroscopic technique, providing valuable information regarding long-range interactions - and associated collective dynamics - occurring in solids. However, the terahertz sciences are relatively nascent, and there have been significant advances over the last several decades that have profoundly influenced the interpretation and assignment of experimental terahertz spectra. Specifically, because there do not exist any functional group or material-specific terahertz transitions, it is not possible to interpret experimental spectra without additional analysis, specifically, computational simulations. Read More

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September 2021

Bioinspired Multifunctional Glass Surfaces through Regenerative Secondary Mask Lithography.

Adv Mater 2021 Sep 13:e2102175. Epub 2021 Sep 13.

Photonic Innovations Lab, Department of Electronic & Electrical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK.

Nature-inspired nanopatterning offers exciting multifunctionality spanning antireflectance and the ability to repel water/fog, oils, and bacteria; strongly dependent upon nanofeature size and morphology. However, such patterning in glass is notoriously difficult, paradoxically, due to the same outstanding chemical and thermal stability that make glass so attractive. Here, regenerative secondary mask lithography is introduced and exploited to enable customized glass nanopillars through dynamic nanoscale tunability of the side-wall profile and aspect ratio (>7). Read More

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September 2021

The electron-transfer intermediates of the oxygen evolution reaction (OER) as polarons by spectroscopy.

Phys Chem Chem Phys 2021 Sep 13. Epub 2021 Sep 13.

Renewable and Sustainable Energy Institute (RASEI), University of Colorado, Boulder, 80303, USA.

The conversion of diffusive forms of energy (electrical and light) into short, compact chemical bonds by catalytic reactions regularly involves moving a carrier from an environment that favors delocalization to one that favors localization. While delocalization lowers the energy of the carrier through its kinetic energy, localization creates a polarization around the carrier that traps it in a potential energy minimum. The trapped carrier and its local distortion-termed a polaron in solids-can play a role as a highly reactive intermediate within energy-storing catalytic reactions but is rarely discussed as such. Read More

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September 2021

Multifunctional Meta-Tribomaterial Nanogenerators for Energy Harvesting and Active Sensing.

Nano Energy 2021 Aug 16;86. Epub 2021 Apr 16.

Department of Civil and Environmental Engineering, University of Pittsburgh, Pittsburgh, PA, USA.

Discovering novel multifunctional metamaterials with energy harvesting and sensing functionalities is likely to be the next technological evolution of the metamaterial science. Here, we introduce a novel concept called self-aware composite mechanical metamaterial (SCMM) that can transform mechanical metamaterials into nanogenerators and active sensing mediums. In pursuit of this goal, we examine new paradigms where finely tailored and seamlessly integrated self-recovering snapping microstructures composed of topologically different triboelectric materials can form self-powering and self-sensing meta-tribomaterial systems. Read More

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Periodical Focusing Phenomenon of Ultrasonic Guided Waves in Pipes.

IEEE Trans Ultrason Ferroelectr Freq Control 2021 Sep 6;PP. Epub 2021 Sep 6.

We put forward a focusing formula to describe the guided waves periodical focusing phenomenon, which, apart from being a fundamental problem in the guided waves propagation in the pipes, has essential applications in the field of nondestructive evaluation. Due to the partial circumferential loads or non-axisymmetric defects, the guided waves are not only in the zeroth-order axisymmetric forms but also in the higher-order non-axisymmetric forms. When multiple orders of the same mode exist simultaneously, the angular profile is adopted to describe the circumferential energy distribution of the superposed wave field. Read More

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September 2021

[Research progress in application of metal-organic framework-derived materials to sample pretreatment].

Se Pu 2021 Sep;39(9):941-949

Minjiang Teachers College, Fuzhou 350108, China.

Sample pretreatment technology plays a vital role throughout the analysis of complex samples. Sample pretreatment can not only increase the concentration of trace targets in the sample, but also effectively eliminate interference from the sample matrix in instrumental analysis. Adsorbent materials are a key component of sample pretreatment technology. Read More

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September 2021

Will we ever wash our hands of lubrication theory?

Authors:
Paul S Hammond

Phys Fluids (1994) 2021 Aug 17;33(8):081908. Epub 2021 Aug 17.

Hammond Consulting Limited, 62 High Street, Bourn, Cambridge CB23 2TR, United Kingdom.

Lubrication theory is used to investigate how weakly bound particles can be transported away from the vicinity of the wall when two spatially periodic rough surfaces are sheared relative to one another at constant velocity while immersed in fluid. The aim is to model what could be an important process during decontamination of hands by washing and is motivated by Mittal ["The flow physics of COVID-19," J. Fluid Mech. Read More

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Doubly Hybrid Functionals Close to Chemical Accuracy for Both Finite and Extended Systems: Implementation and Test of XYG3 and XYGJ-OS.

JACS Au 2021 May 19;1(5):543-549. Epub 2021 Apr 19.

Collaborative Innovation Center of Chemistry for Energy Materials, Shanghai, Key Laboratory of Molecular Catalysis and Innovative Materials, MOE Key Laboratory of Computational Physical Sciences, Shanghai Key Laboratory of Bioactive Small Molecules, Department of Chemistry, Fudan University, Shanghai 200433, People's Republic of China.

While being widely used to understand the chemical reactions in heterogeneous catalysis or other multidisciplinary systems, a great challenge that semilocal and hybrid density functional approximations (DFAs) are facing is to deliver a uniformly accurate description for both finite and extended systems. Herein, we perform reliable and well-converged periodic calculations of two doubly hybrid approximations (DHAs), XYG3 and XYGJ-OS, and demonstrate that the good accuracy of DHAs achieved for molecules is transferable to the semiconductors and insulators. Such an accuracy is not only for energetic properties but also for the first- and second-order response properties, which is general for different kinds of chemical environments, including simple cubic bulks, perovskite-type transition metal oxides like TiO, and heterogeneous systems like CO adsorption on the NaCl(100) surface. Read More

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Dynamical Variations of the Global COVID-19 Pandemic Based on a SEICR Disease Model: A New Approach of Yi Hua Jie Mu.

Geohealth 2021 Aug 1;5(8):e2021GH000455. Epub 2021 Aug 1.

Department of Geography Hong Kong Baptist University Hong Kong China.

The ongoing coronavirus disease 2019 (COVID-19) pandemic has caused more than 150 million cases of infection to date and poses a serious threat to global public health. In this study, global COVID-19 data were used to examine the dynamical variations from the perspectives of immunity and contact of 84 countries across the five climate regions: tropical, arid, temperate, and cold. A new approach named Yi Hua Jie Mu is proposed to obtain the transmission rates based on the COVID-19 data between the countries with the same climate region over the Northern Hemisphere and Southern Hemisphere. Read More

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High carbon losses from oxygen-limited soils challenge biogeochemical theory and model assumptions.

Glob Chang Biol 2021 Aug 31. Epub 2021 Aug 31.

Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, USA.

Oxygen (O ) limitation contributes to persistence of large carbon (C) stocks in saturated soils. However, many soils experience spatiotemporal O  fluctuations impacted by climate and land-use change, and O -mediated climate feedbacks from soil greenhouse gas emissions remain poorly constrained. Current theory and models posit that anoxia uniformly suppresses carbon (C) decomposition. Read More

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Light Absorption in Nanowire Photonic Crystal Slabs and the Physics of Exceptional Points: The Shape Shifter Modes.

Sensors (Basel) 2021 Aug 11;21(16). Epub 2021 Aug 11.

Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 2601, Australia.

Semiconductor nanowire arrays have been demonstrated as promising candidates for nanoscale optoelectronics applications due to their high detectivity as well as tunable photoresponse and bandgap over a wide spectral range. In the infrared (IR), where these attributes are more difficult to obtain, nanowires will play a major role in developing practical devices for detection, imaging and energy harvesting. Due to their geometry and periodic nature, vertical nanowire and nanopillar devices naturally lend themselves to waveguide and photonic crystal mode engineering leading to multifunctional materials and devices. Read More

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Biodiversity in a Cool-Climate Vineyard: A Case Study from Quebec.

Insects 2021 Aug 19;12(8). Epub 2021 Aug 19.

Plant Select, 1190 Principale West St., St.-Paul-d'Abbotsford, QC J0E 1A0, Canada.

In Quebec (Canada), viticulture has experienced steady growth in the last 35 years in terms of surfaces cultivated and value, although it is practiced in climatic conditions at the edge of what is considered a cool-climate area. This case study documents biodiversity studies conducted at the l'Orpailleur vineyard (Dunham, QC, Canada) from 1997 to 2021. In a first phase starting in 1997, the biodiversity of insecticide-free and insecticide-treated plots was determined for the taxa Scarabaeidae, Curculionidae, Chrysomelidae, Cicadellidae, Acari and Aranae. Read More

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Refractory serum immunoglobulin M elevation during anti-interleukin (IL)-1- or IL-6-targeted treatment in four patients with Schnitzler syndrome.

J Dermatol 2021 Aug 26. Epub 2021 Aug 26.

Department of Dermatology, Kyoto University Graduate School of Medicine, Kyoto, Japan.

Schnitzler syndrome is characterized by chronic urticarial rash, neutrophilic dermal infiltrate, recurrent fever, bone pain, elevated C-reactive protein, and neutrophilic leukocytosis. The pathophysiology of Schnitzler syndrome is unknown, but it is considered to be an acquired form of an autoinflammatory disease because of the resemblance to clinical phenotypes of cryopyrin-associated periodic syndrome, in which a gain-of-function mutation in NLRP3 causes overexpression of interleukin (IL)-1β. Schnitzler syndrome is generally accompanied by a monoclonal immunoglobulin (Ig)M gammopathy with a long-term risk of lymphoproliferation that is possibly associated with an MYD88 mutation. Read More

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Lifting restrictions on coherence loss when characterizing non-transparent hypersonic phononic crystals.

Sci Rep 2021 Aug 25;11(1):17174. Epub 2021 Aug 25.

Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany.

Hypersonic phononic bandgap structures confine acoustic vibrations whose wavelength is commensurate with that of light, and have been studied using either time- or frequency-domain optical spectroscopy. Pulsed pump-probe lasers are the preferred instruments for characterizing periodic multilayer stacks from common vacuum deposition techniques, but the detection mechanism requires the injected sound wave to maintain coherence during propagation. Beyond acoustic Bragg mirrors, frequency-domain studies using a tandem Fabry-Perot interferometer (TFPI) find dispersions of two- and three-dimensional phononic crystals (PnCs) even for highly disordered samples, but with the caveat that PnCs must be transparent. Read More

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Periodic fever, aphthous stomatitis, pharyngitis, and adenitis (PFAPA) syndrome: A review.

World J Otorhinolaryngol Head Neck Surg 2021 Jul 27;7(3):166-173. Epub 2021 Jun 27.

Department of Otolaryngology and Communication Enhancement, Boston Children's Hospital, Boston, MA, USA.

Periodic fever, aphthous stomatitis, pharyngitis, and adenitis (PFAPA) syndrome is the most common periodic fever condition in children, with most cases appearing by the age of 5. Although PFAPA is generally a self-limited condition, it can have a major impact on a child's quality of life, as well as that of their family. Recent research has continued to shed light on the genetic and immunologic factors that play a role in the pathogenesis of PFAPA. Read More

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Acute encephalitis in pediatric multisystem inflammatory syndrome associated with COVID-19.

Eur J Paediatr Neurol 2021 Aug 5;34:84-90. Epub 2021 Aug 5.

Vittore Buzzi Children's Hospital, Pediatric Neurology Unit, Via Castelvetro, 32, 20154, Milan, Italy. Electronic address:

Objective: To characterize neurological involvement in multisystem inflammatory syndrome in children (MIS-C) related to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

Methods: Retrospective analysis of the clinical, electroencephalographic, CSF and neuroradiological parameters recorded in seven children (3 males, aged 3-10 years) affected by MIS-C with acute neurological involvement.

Results: All cases presented acute encephalopathy with drowsiness, irritability, mood deflection and diffuse EEG slowing with periodic posterior complexes. Read More

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Emerging two-dimensional monoelemental materials (Xenes): Fabrication, modification, and applications thereof in the field of bioimaging as nanocarriers.

Wiley Interdiscip Rev Nanomed Nanobiotechnol 2021 Aug 20:e1750. Epub 2021 Aug 20.

Department of Thyroid and Breast Surgery, The First Affiliated Hospital of University of Science and Technology of China, Hefei, Anhui, China.

In recent years, more and more research enthusiasm has been devoted to the development of emerging two-dimensional (2D) monoelement materials (Xenes) and explored potential applications in various fields, especially biomedicine and bioimaging. The inspiring results attribute to their excellent physicochemical properties, including adjustable band gap, surface electronic layout characteristics, and so on, making it easier for surface modification in order to meet designated needs. As a popular interdisciplinary research frontier, a variety of methods for fabricating 2D Xenes have recently been adopted for pre-preparing future practical bioimaging applications, which implies that these materials will have broad clinical application prospects in the future. Read More

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A mechanism for sarcomere breathing: volume change and advective flow within the myofilament lattice.

Biophys J 2021 Sep 10;120(18):4079-4090. Epub 2021 Aug 10.

School of Physics & School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia. Electronic address:

During muscle contraction, myosin motors anchored to thick filaments bind to and slide actin thin filaments. These motors rely on energy derived from ATP, supplied, in part, by diffusion from the sarcoplasm to the interior of the lattice of actin and myosin filaments. The radial spacing of filaments in this lattice may change or remain constant during contraction. Read More

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September 2021

A SAS macro for modelling periodic data using cosinor analysis.

Comput Methods Programs Biomed 2021 Sep 23;209:106292. Epub 2021 Jul 23.

Section of Pulmonary, Critical Care, and Sleep Medicine, Department of Internal Medicine, Yale School of Medicine, New Haven, CT, United States.

Background And Objective: Cosinor analysis, developed by Franz Hallberg and colleagues in the 1960s, allows for the fitting of a cosine curve to data of a known period. Cosinor analysis is frequently used in the analysis of biological rhythm data. While software exists to perform these analyses, we are not aware of any published SAS procedures or macros which would facilitate them. Read More

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September 2021

Spatiotemporal evolutionary analysis of rainfall erosivity during 1901-2017 in Beijing, China.

Environ Sci Pollut Res Int 2021 Aug 9. Epub 2021 Aug 9.

Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Sciences, Northwest University, Xi'an, 710127, China.

Rainfall erosivity is regarded as one of the main factors affecting soil erosion. Based on 117-year monthly precipitation data of Beijing from 1901 to 2017, the  spatiotemporal evolutionary analysis of rainfall erosivity in Beijing were analyzed by using Theil-Sen median analysis (Sen), the Mann-Kendall (MK) trend test, R/S analysis method, cumulative anomaly method, MK mutation test method, Pettitt test, and wavelet analysis. The results showed that the average annual rainfall erosivity in Beijing ranged from 1080. Read More

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Psychometric properties of the Somatic Symptom Scale 8 (SSS-8) in a representative sample of German adolescents.

J Psychosom Res 2021 Oct 2;149:110593. Epub 2021 Aug 2.

Zürcher Hochschule für Angewandte Wissenschaften, Zürich, Switzerland.

Objective: The psychometric properties of the Somatic Symptom Scale 8 (SSS-8) have been investigated in different studies. However, there is no study examining its psychometric properties on representative data of adolescents. The study at hand will present results from a large representative sample of German adolescents (13 to 18 years). Read More

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October 2021

Automated detection and quantification of Wilms' Tumor 1-positive cells in murine diabetic kidney disease.

Proc SPIE Int Soc Opt Eng 2021 Feb 15;11603. Epub 2021 Feb 15.

Department of Pathology and Anatomical Sciences, University at Buffalo, Buffalo, NY.

In diabetic kidney disease (DKD), podocyte depletion, and the subsequent migration of parietal epithelial cells (PECs) to the tuft, is a precursor to progressive glomerular damage, but the limitations of brightfield microscopy currently preclude direct pathological quantitation of these cells. Here we present an automated approach to podocyte and PEC detection developed using kidney sections from mouse model emulating DKD, stained first for Wilms' Tumor 1 (WT1) (podocyte and PEC marker) by immunofluorescence, then post-stained with periodic acid-Schiff (PAS). A generative adversarial network (GAN)-based pipeline was used to translate these PAS-stained sections into WT1-labeled IF images, enabling label-free podocyte and PEC identification in brightfield images. Read More

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February 2021

Episodic syndromes that may be associated with migraine: What adult neurologists need to know.

Authors:
S Redon

Rev Neurol (Paris) 2021 Sep 5;177(7):773-778. Epub 2021 Aug 5.

Department of Evaluation and Treatment of Pain, FHU INOVPAIN, la Timone Hospital, AP-HM, Marseille, France. Electronic address:

Four episodic syndromes are recognized in the current version of the International Classification of Headache Disorders (ICHD): cyclic vomiting syndrome (CVS); abdominal migraine; benign paroxysmal vertigo; benign paroxysmal torticollis. Previously called childhood periodic syndromes, they are thought to be early expressions of a migrainous spectrum. They usually occur in childhood or adolescence and some of these patients will develop migraine later in childhood or in adulthood. Read More

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September 2021