Revisiting Multiplication Area Models for Whole Numbers

We argue that there are two conceptually different area models for whole number multiplication: area-to-area model and lengths-to-area model depending on how multiplication operation is conceived: action on / change of an initial quantity, or operation / coordination of two quantities. These models complement each other to promote students’ conceptual understanding of whole number multiplication and help students extend their understanding of whole number multiplication to fraction multiplication

Revisiting Multiplication Area Models for Whole Numbers

We argue that there are two conceptually different area models for whole number multiplication: area-to-area model and lengths-to-area model depending on how multiplication operation is conceived: action on / change of an initial quantity, or operation / coordination of two quantities. These models complement each other to promote students’ conceptual understanding of whole number multiplication and help students extend their understanding of whole number multiplication to fraction multiplication

Clinical Efficacy of Near-Infrared Reflectance Imaging and Optical Coherence Tomography in Identifying Ocular Manifestations of Neurofibromatosis Type 1 in Korean Children

Purpose The aim of this study was to investigate the clinical efficacy of near-infrared reflectance (NIR) imaging and optical coherence tomography (OCT) in identifying ocular manifestations of neurofibromatosis type 1 (NF1) in Korean children. Methods This retrospective chart review study included five Korean children with NF1 aged under 18 years who had undergone ophthalmic procedures, including slit-lamp examinations, NIR imaging, and OCT scanning. Results Multiple patchy bright lesions were observed on NIR imaging in all eyes (10 eyes in five patients). Further NIR imaging and OCT scans showed that these lesions, confined to the choroid, were choroidal nodules. Lisch nodules, contrastingly, were found in only four of 10 eyes by slit-lamp examinations on the same day as the NIR imaging. One of those four eyes had only one Lisch nodule, which did not meet the NF1 diagnostic criteria. Conclusion NIR imaging enabled the detection of choroidal nodules in Korean children with NF1. Moreover, for Korean children with NF1, choroidal nodules were earlier-detected ocular manifestations relative to Lisch nodules. NIR imaging, along with OCT, is a useful protocol for localizing NF1 nodules in children

Emission Rates of Volatile Organic Compounds Released from Newly Produced Household Furniture Products Using a Large-Scale Chamber Testing Method

The emission rates of volatile organic compounds (VOCs) were measured to investigate the emission characteristics of five types of common furniture products using a 5 m3 size chamber at 25°C and 50% humidity. The results indicated that toluene and α-pinene are the most dominant components. The emission rates of individual components decreased constantly through time, approaching the equilibrium emission level. The relative ordering of their emission rates, if assessed in terms of total VOC (TVOC), can be arranged as follows: dining table > sofa > desk chair > bedside table > cabinet. If the emission rates of VOCs are examined between different chemical groups, they can also be arranged in the following order: aromatic (AR) > terpenes (TER) > carbonyl (CBN) > others > paraffin (PR) > olefin (HOL) > halogenated paraffin (HPR). In addition, if emission strengths are compared between coated and uncoated furniture, there is no significant difference in terms of emission magnitude. Our results indicate that the emission characteristics of VOC are greatly distinguished between different furniture products in terms of relative dominance between different chemicals

Biochemical characterization of a recombinant Japanese encephalitis virus RNA-dependent RNA polymerase

<p>Abstract</p> <p>Background</p> <p>Japanese encephalitis virus (JEV) NS5 is a viral nonstructural protein that carries both methyltransferase and RNA-dependent RNA polymerase (RdRp) domains. It is a key component of the viral RNA replicase complex that presumably includes other viral nonstructural and cellular proteins. The biochemical properties of JEV NS5 have not been characterized due to the lack of a robust <it>in vitro </it>RdRp assay system, and the molecular mechanisms for the initiation of RNA synthesis by JEV NS5 remain to be elucidated.</p> <p>Results</p> <p>To characterize the biochemical properties of JEV RdRp, we expressed in <it>Escherichia coli </it>and purified an enzymatically active full-length recombinant JEV NS5 protein with a hexahistidine tag at the N-terminus. The purified NS5 protein, but not the mutant NS5 protein with an Ala substitution at the first Asp of the RdRp-conserved GDD motif, exhibited template- and primer-dependent RNA synthesis activity using a poly(A) RNA template. The NS5 protein was able to use both plus- and minus-strand 3'-untranslated regions of the JEV genome as templates in the absence of a primer, with the latter RNA being a better template. Analysis of the RNA synthesis initiation site using the 3'-end 83 nucleotides of the JEV genome as a minimal RNA template revealed that the NS5 protein specifically initiates RNA synthesis from an internal site, U₈₁, at the two nucleotides upstream of the 3'-end of the template.</p> <p>Conclusion</p> <p>As a first step toward the understanding of the molecular mechanisms for JEV RNA replication and ultimately for the <it>in vitro </it>reconstitution of viral RNA replicase complex, we for the first time established an <it>in vitro </it>JEV RdRp assay system with a functional full-length recombinant JEV NS5 protein and characterized the mechanisms of RNA synthesis from nonviral and viral RNA templates. The full-length recombinant JEV NS5 will be useful for the elucidation of the structure-function relationship of this enzyme and for the development of anti-JEV agents.</p

Very short-term forecasting of precipitation based on hybrid surface rainfall technique in Korea

Póster presentado en: 3rd European Nowcasting Conference, celebrada en la sede central de AEMET en Madrid del 24 al 26 de abril de 2019

A Case of Lewis-Sumner Syndrome Showing Dramatic Improvement after Plasma Exchange

We report a patient with Lewis-Sumner syndrome (LSS) who showed an improvement only with plasma exchange (PE). The patient, 32-yr old man, had progressive multifocal motor-sensory deficits with persistent, multiple conduction blocks and marked slowing of NCVs. Nerve pathology supported a diagnosis of demyelinating neuropathy by revealing marked loss of myelinated fibers with inter- and intrafascicular variation. Although the patient was refractory to treatment with corticosteroid and intravenous immunoglobulin, PE produced a dramatic improvement. Our experience strongly proposes that PE should be tried for refractory LSS