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[Oral Session 2] MECHANISM OF PAPER SIZING BY REACTIVE SIZES:AKD, ASA AND FATTY ACID ANHYDRIDES
A.Isogai 한국펄프·종이공학회 1999 한국펄프종이학회 기타 간행물 Vol.- No.-
Mechanisms of paper sizing by reactive sizes such as alkylketene dimers (AKD), alkenylsuccinic anhydrides (ASA) and fatty acid anhydrides (FAA) arc reviewed on the basis of the results obtained in our laboratory. Solid-state ¹ ³C-NMR analysis of cellulase-treated residues of handsheets prepared with ¹ ³C-labeled sizes showed that the size components are present primarily as hydrolyzed products, without forming covalent bonds with hydroxyl groups of cellulose in the handsheets. Furthermore, most size components in handsheets were removed by stirring the defibrated handsheets in water with Tween 80 at 70℃ for 4 h. Thus, the hydrolyzed products of size molecules consequently contribute to sizing performance for the reactive size-treated papers. Scanning electron microscopic observations revealed that the chemical structures of reactive sizes are necessary for efficient paper sizing to achieve homogenous distribution of hydrophobic size components on hydrophilic pulp fiber surfaces in the papermaking process, where water is always present. Size reversion is presumably explained in terms of partial introduction of hydrophilic groups into the size molecules by auto-oxidation. Therefore, mechanisms of paper sizing by reactive sizes can be rationalized, without introducing the covalent bond formations. by changes in chemical structures of the size molecules from hydrophilic to hydrophobic by hydrolysis in papermaking process. Model experiments using a cellulose-AKD ester sample also supported these mechanisms.
A distinct functional distribution of α and γ motoneurons in the rat trigeminal motor nucleus
Morita-Isogai, Yukako,Sato, Hajime,Saito, Mitsuru,Kuramoto, Eriko,Yin, Dong Xu,Kaneko, Takeshi,Yamashiro, Takashi,Takada, Kenji,Oh, Seog Bae,Toyoda, Hiroki,Kang, Youngnam Springer-Verlag 2017 BRAIN STRUCTURE AND FUNCTION Vol.222 No.7
<P>Gamma-motoneurons (gamma MNs) play a crucial role in regulating isometric muscle contraction. The slow jaw-closing during mastication is one of the most functional isometric contractions, which is developed by the rank-order recruitment of alpha-motoneurons (alpha MNs) in a manner that reflects the size distribution of alpha MNs. In a mouse spinal motor nucleus, there are two populations of small and large MNs; the former was identified as a population of gamma MNs based on the positive expression of the transcription factor estrogen-related receptor 3 (Err3) and negative expression of the neuronal DNA-binding protein NeuN, and the latter as that of alpha MNs based on the opposite pattern of immunoreactivity. However, the differential identification of alpha MNs and gamma MNs in the trigeminal motor nucleus (TMN) remains an assumption based on the size of cell bodies that were retrogradely stained with HRP. We here examined the size distributions of alpha MNs and gamma MNs in the dorsolateral TMN (dl-TMN) by performing immunohistochemistry using anti-Err3 and anti-NeuN antibodies. The dl-TMN was identified by immunopositivity for vesicular glutamate transporter-1. Immunostaining for choline acetyltransferase and Err3/NeuN revealed that the dl-TMN is composed of 65% alpha MNs and 35% gamma MNs. The size distribution of alpha MNs was bimodal, while that of gamma MNs was almost the same as that of the population of small alpha MNs , suggesting the presence of alpha MNs as small as gamma MNs. Consistent with the size concept of motor units, the presence of smaller jaw-closing alpha MNs was coherent with the inclusion of jaw-closing muscle fibers with smaller diameters compared to limb muscle fibers.</P>
Development of a Resonance Type Flapping Wing for a Dragonfly-Type Micro Aerial Vehicle
Koji Isogai,Kazuya Maesato,Yuichi Kamisawa,Kenji Sato 한국항공우주학회 2008 한국항공우주학회 학술발표회 논문집 Vol.- No.-
The paper presents the development of resonance type flapping wings for a dragonfly-type micro aerial vehicle. which show high performance in spite of their simple structures and light weight. The wings (fore- and hind-wings) are composed of a single carbon rod of 1 ㎜ diameter and the thin EPP (Expanded Polypropylene) plate of 1.5 ㎜ thickness for the fore-wing and 3.0 ㎜ thickness for the hind-wing, respectively. The semi-span lengths of the wings are 0.11 m. The planforrns of the fore- and hind-wings are those of Onychogomphus viridicastus. The mass of the fore-wing is 0.25 g and that of the hind-wing is 0.30 g. The first natural frequencies of the fore- and hind-wings are 39 Hz and 47 Hz, respectively. The detailed performance of the wings such as time mean thrust and necessary power in still air (hovering condition) are measured using the vibration test bed. For example, the thrust is 0.095 N for the fore-wing and 0.111 N for the hind-wing at the frequency of 40 Hz. This means that the dragonfly-type MAV which employs the two-pairs of those flapping wings can generate the lift of 0.41 N (in hovering condition) at 40 Hz. In order to confirm this, a hovering demonstrator (mass: 40 g) which employs the present two pairs of the wings was built and tested. verifying that it can generate the lift which is larger than its own weight at flapping frequency of 40 Hz. The paper also presents the results of the numerical simulations of those flapping wings using a 3D Navier-Stokes code which takes into account aeroelastic effects.
Ishii Ken,Isogai Norihiro,Shiono Yuta,Yoshida Kodai,Takahashi Yoshiyuki,Takeshima Kenichiro,Nakayama Masanori,Funao Haruki 대한척추외과학회 2021 Asian Spine Journal Vol.15 No.4
Study DesignRetrospective cohort study.PurposeThis study aimed to evaluate aggravated lateral recess stenosis and clarify the indirect decompression threshold by combined lateral interbody fusion and percutaneous pedicle screw fixation (LIF/PPS).Overview of LiteratureNo previous reports have described an effective radiographic indicator for determining the surgical indication for LIF/PPS.MethodsA retrospective review of 185 consecutive patients, who underwent 1- or 2-level lumbar fusion surgery for degenerative spondylolisthesis (DS). According to their symptomatic improvement, they were placed into either the “recovery” or “no-recovery” group. Preoperative computed tomography (CT) images were evaluated for the position of the superior articular processes at the slipping level, followed by a graded classification (grades 0–3) using the impingement line (I line), a new radiographic indicator. All 432 superior articular facets in 216 slipped levels were classified, and both groups’ characteristics were compared.ResultsThere were 171 patients (92.4%) in the recovery group and 14 patients in the no-recovery group (7.6%). All patients in the no-recovery group were diagnosed with symptoms associated with deteriorated bony lateral recess stenosis. All superior articular processes of the lower vertebral body in affected levels reached and exceeded the I line (I line-; grade 2 and 3) on preoperative sagittal CT images. In the recovery group, most superior articular processes did not reach the I line (I line+; grade 0 and 1; p=0.0233).ConclusionsIn DS cases that are classified as grade 2 or greater, the risk of aggravated bony lateral recess stenosis due to corrective surgery is high; therefore, indirect decompression by LIF/PPS is, in principle, contraindicated.
[Poster Presentation] MECHANISMS OF RETENTION AND SIZING DEVELOPMENT IN ROSIN SOAP SIZING
K.Ohno,A.Isogai,F.Qnabe 한국펄프·종이공학회 1999 한국펄프종이학회 기타 간행물 Vol.- No.-
Sizing development and retention mechanism in rosin soap size-alum systems were studied. Rosin size and aluminum contents in hand sheets, which were prepared under various conditions, were determined by X-ray fluorescence analysis and pyrolysis-gas chromatography, respectively. ¹³C-labeled palmitic acid potassium salt was used as a model of rosin soap size, and chemical structures of size components in hand sheets were analyzed by solid-state ¹³C-NMR. The relationships among sizing degree, size retention and aluminum content in handsheets were obtained in terms of various handsheetconditions. Especially, most aluminum compounds originating from alum added to pulp suspensions are immediately adsorbed on pulp fibers and form cationic sites. Anionic rosin size components are then adsorbed on the cationic sites. When the ¹³C-labled palmitic acid soap size was used in handsheet-making, calcium palmitate was present as a major component in the handsheets. Molecules of free palmitic acid and aluminum palmitate were present as minor components. Formation of aluminum palmitate must be significant for size retention at the wet-end. However, it is not plausible that only aluminum palmitate molecules present in the handsheets as a quite minor component govern overall sizing performance. Molecules of calcium palmitate and free palmitic acid as well as aluminum palmitate probably behave as hydrophobic compounds in the handsheets, and contribute to sizing performance.