중등도 이하 소아 근시에서 안경과 각막굴절교정렌즈 착용이 안축장 성장에 미치는 영향 비교

김태희(Tae Hee Kim),김명훈(Myung Hun Kim),곽주영(Joo Young Kwag),최진석(Jin Seok Choi),박규홍(Kyu Hong Pak),이경욱(Kyeongwook Lee),박태성(Taeseong Park),정성근(Sung Kun Chung),현주(Joo Hyun) 대한안과학회 2018 대한안과학회지 Vol.59 No.11

목적: 중등도 이하 소아 근시에서 안경과 각막굴절교정렌즈(orthokeratology lens, OK) 착용이 안축장 성장에 미치는 영향 및 관련인자를 알아보고자 하였다. 대상과 방법: 2013년부터 2015년까지 내원한 6세에서 13세 사이 -4.50디옵터 이하의 구면렌즈대응치를 가진 소아 100명을 대상으로 후향적으로 OK군(75안)과 안경군(64안) 간에 안축장 변화와 안축장과 관계된 인자들을 분석하였다. 결과: 안축장 변화는 1년째에 OK군이 0.24 ± 0.29 mm의 증가를, 안경군이 0.42 ± 0.20 mm의 증가를 보였으며, OK군에서 안경군에 비해 유의하게 안축장 성장이 억제되는 양상을 보였다(Mann-Whitney U test, p<0.05). OK군에서 처음 착용한 나이만이 안축장 변화와 음의 상관관계가 있는 것으로 나타났다(Pearson’s correlation, r=-0.481, p<0.05). 안경군에서는 처음 착용한 나이가 안축장 변화와 음의 상관관계(Pearson’s correlation, r=-0.462, p<0.05)를, 그 외에 현성굴절검사의 초기 구면렌즈대응치 및 초기 구면렌즈값, 난시값은 안축장 변화와 양의 상관관계를 보였다. 안축장 변화를 비교해 보았을 때 OK를 착용한 경우 6세 이상 9세 미만군(28안)에비해 9세 이상 13세 이하군(47안)에서 유의하게 안축장 성장이 더 억제되는 양상을 보였다(Mann-Whitney U test, p<0.05). 결론: OK 착용은 안경 착용에 비해 효과적으로 안축장의 성장을 억제할 수 있으며, 9세 이상 13세 이하의 소아에서도 효과적인 안축장 성장 억제가 가능하다. Purpose: To assess the effect on axial elongation and associated factors between spectacles and of orthokeratology lens (OK) wearing in children with mild to moderate myopia. Methods: A total of one hundred subjects, ranging in age from 6 to 13 years, and with mild to moderate myopia no more than -4.50 diopters in spherical equivalent, visited our clinic from 2013 to 2015. The OK group (75 eyes) and the spectacles group (64 eyes) were compared and analyzed on the axial elongation and associated factors. Results: In the OK group, axial length was elongated in 1 year period with a mean increase of 0.24 ± 0.29 mm. In spectacles group, axial length was elongated in 1 year period with a mean increase of 0.42 ± 0.20 mm. The statistically significant suppression of axial elongation was observed in OK group compared to the spectacles group (Mann-Whitney U test, p < 0.05). For OK group, the age of starting OK (Pearson’s correlation, r = -0.481, p < 0.05) was the only influencing factor on axial elongation, which had negative correlation with axial elongation. In spectacles group, the age of starting spectacles had negative correlation with axial elongation (Pearson’s correlation, r = -0.462, p < 0.05) and baseline spherical equivalent, spherical diopter, cylindrical diopter from manifest refraction had positive correlation with axial elongation. Comparison of axial elongation in orthokeratology lens group and spectacles group by age groups (6 to 9 years [28 eyes], 9 to 13 years [47 eyes]), 9 to 13 years of orthokeratology lens group had the stronger suppression of axial elongation (Mann-Whitney U test, p < 0.05). Conclusions: The OK effectively suppresses axial elongation compared to the spectacles. Although the patients are in age from 9 to 13 years, the axial elongation was effectively suppressed.

머시닝 센터 이송계 신장 분석

조창영,최현웅,김동규,추원식,김산,송철기 대한기계학회 2024 大韓機械學會論文集A Vol.48 No.5

공작기계는 제조산업의 기반을 이루는 우수한 성능의 가공정밀도를 가진 핵심 장치이다. 가공 정밀도에 영향을 주는 오차는 다양한 환경 및 조건에서 발생된다. 그 중에서 기계 열변형에 의한 이송축(feed-axis) 열변위(thermal displacement)는 그 크기와 방향을 예측하고 제어하기 어렵다. 이러한 누적된 열변위는 이송축 신장량(elongation amount)으로 정량화될 수 있다. 일부 공작기계 제조사들은 제품출하 전에 조립품질 및 가공정밀도를 검증하기 위하여 이송축 신장 시험(elongation test)을 시행하고 있다. 본 연구에서는 공작기계 머시닝 센터 이송축 위치결정 정도 시험으로 61개 기종의 신장 시험 데이터를 얻었다. 이송축 신장량 절대값을 기준으로 4개 등급으로 분류하여, 공작기계 사양(구조, 가이드 종류, 스트로크 등)에 따른 신장량 특성을 분석하였다. 신장 형태 구분을 위한 최적 기준값을 선정하여 이송축 양 끝단의 위치 이동에 따른 신장 형태를 5가지로 분류하였다. 또한 신장 형태에 따라 가공 오차에 미치는 영향을 분석하고자 하였다. Machine tools are core devices with excellent performance in terms of machining precision and are the foundation of the manufacturing industry. Errors affecting machining precision arise from various environments and conditions. Among them, thermal displacement of the feed axis due to mechanical thermal deformation presents challenges in predicting and controlling its magnitude and direction. This accumulated displacement can be quantified as feed-axis elongation. Some machine-tool manufacturers conduct elongation tests on the feed axis to verify the assembly quality and machining precision prior to product shipment. In this study, we obtain elongation-test data for 61 machine-tool machining centers via feed-axis positioning-accuracy tests. The elongation is classified into four grades based on the absolute value of the feed-axis elongation. We analyze the characteristics of elongation based on the machine-tool specifications, such as the structure, guide type, and stroke. Optimal criteria for classifying the elongation types are selected, and elongation is categorized into five types based on the positional movement of both ends of the feed axis. Additionally, we analyze the effect of elongation type on machining error.

Effect of Auxin and Ethylene on Elongation of Intact Primary Roots of Maize(Zea mays L.)

Kim, Soon Young,Mulkey, Timothy J. 한국식물학회 1997 Journal of Plant Biology Vol.40 No.4

We tested that the hypothesis that root elongation might be controlled by altering the level of ethylene in intact primary roots of maize (Zea mays L.). We measured root elongation in a short period using a computerized root auxanometer. Compounds which regulate ethylene production were applied to intact primary roots in different time periods. Root elongation was stimulated by the treatment with ethylene antagonists such as Co^2+, aminoethoxyvinylglycine (AVG) and L-canaline. This result suggested that root elongation was closely related to ethylene level of intact primary roots. Furthermore, IAA- and 1-aminocyclopropane-1-carboxylic acid (ACC)-induced inhibition of root elongation was reversed by treatment with Co^2+. The application of ACC to roots which have been exposed to IAA and Co^2+ have no significant effect on root elongation. However, the inhibition of root elongation by ACC in roots previously treated with IAA and AVG became manifest when the applied IAA concentrations were lower. These results were consistent with the hypothesis that the level of ethylene in intact roots functions to moderate root elongation, and suggested that auxin-induced inhibition of root elongation results from auxin induced promotion of ethylene production.

황반원공수술에서 내경계막제거술의 크기와 술 후 중심와 조직 신장의 연관성

박재홍,전혜민,윤희성,Jae Hong Park,Hye Min Jeon,Hee Seong Yoon 대한안과학회 2014 대한안과학회지 Vol.55 No.12

Purpose: To evaluate the relationship between the size of internal limiting membrane (ILM) peeling and the elongation of foveal tissue after macular hole (MH) surgery. Methods: The medical records of 29 patients (29 eyes) who developed elongation of foveal tissue on spectral domain optical coherence tomography (OCT) after vitrectomy with ILM peeling and gas tamponade for idiopathic MH were retrospectively reviewed. These eyes were classified into 3 subgroups by the size of ILM peeling: group A (9 eyes), smaller than 2 disc diameter (DD); group B (12 eyes), larger than 2 DD and within the major temporal vascular arcade, and group C (8 eyes), till the edge of the major temporal vascular arcade. Inter-outer plexiform layer (OPL) distance, representing elongation of foveal tissue, was measured 1, 3, and 6-8 months (only 18 eyes) postoperatively. ‘Asymmetric elongation’ was defined as non-uniform elongation of the foveal tissue in certain directions. Results: Horizontal/vertical inter-OPL distances 1 month postoperative, in descending order, were: group B, 436.58 ± 88.54 / 404.92 ± 78.55 μm; group A, 421.33 ± 109.97 / 404.14 ± 120.9 μm; and C group, 389.25 ± 48.75 / 400 ± 52.23 μm. Variations in the horizontal/vertical inter-OPL distance 3 months after MH surgery were: group B, 136.83 ± 65.64 / 103.92 ± 73.37 μm; group A, 88.11 ± 41.57 / 75.89 ± 53.18 μm; and group C, 140.25 ± 68.51 / 83.63 ± 56.62 μm. There were no significant differences in inter-OPL distance, variation in inter-OPL distance, or percent asymmetry in both horizontal and vertical directions among these groups. Conclusions: Elongation of the foveal tissue and asymmetric elongation after MH surgery were not associated with the size of ILM peeling. J Korean Ophthalmol Soc 2014;55(12):1860-1867

고분자압출필름의 연신에 관한 연구

최만성(Choi, Man-Sung) 한국산학기술학회 2014 한국산학기술학회논문지 Vol.15 No.2

다량의 무기물이 첨가된 고분자제품을 초박막의 두께로 고속생산 할 경우 가장 중요한 요소는 적절한 원재 료의 선정도 중요하지만 대개의 경우 한정된 범위의 수지를 사용할 수밖에 없기 때문에, 가장 중요한 요소는 압출기 내에서 흘러나온 용융수지의 흐름을 균일하게 유지할 수 있도록 고분자의 용융 유동에 적합한 최적의 다이스 설계와 압출기의 공정 파라미터의 제어를 통해 균일한 두께 유지와 연신이 필요하다. 이와 관련하여 고분자 압출필름의 적절 한 연신을 위하여 압출조건이 연신에 미치는 영향에 대한 연구가 필요하지만 관련된 연구는 아직 충분히 이루어지지 않고 있다. 따라서 본 연구는 통기성 필름의 압출필름에 주로 사용되는 LLDPE(Linear Low Density Polyethylene)에 대하여 압출기의 실린더 온도, 압출속도, 압출기의 다이스온도, 냉각롤의 온도, 연신비, 그리고 연신롤 온도 등의 압출 조건의 변화가 압출필름의 연신에 미치는 영향에 대하여 압출실험을 통하여 연구하였다. 연구결과에서 연신비가 2.0:1 일 때 고분자압출필름의 연신에 가장 큰 영향을 미침을 알 수 있었다. Optimization of process parameters in polymer extrusion is an important task to reduce manufacturing cost. To determine the optimum values of the process parameters, it is essential to find their influence on the elongation of polymer breathable thin film. The significance of six important process parameters namely, extruder cylinder temperature, extruder speed, extruder dies temperature, cooling roll temperature, stretching ratio, stretching roll temperature on breathable film elongation of polymer extrusion was determined. Moreover, this paper presents the application of Taguchi method and analysis of variance(ANOVA) for maximization of the breathable film elongation influenced by extrusion parameters. The optimum parameter combination of extrusion process was obtained by using the analysis of signal-to-noise ratio. The conclusion revealed that stretching ratio were the most influential factor on the film elongation. The best results of film elongation were obtained at lower stretching ratio.

Mapping and characterization of quantitative trait loci for mesocotyl elongation in rice ( <i>Oryza sativa</i> L.)

Lee, Hyun-Sook,Sasaki, Kazuhiro,Higashitani, Atsushi,Ahn, Sang-Nag,Sato, Tadashi Springer New York 2012 Rice Vol.5 No.-

<P>Mesocotyl elongation is an important trait for seedling emergence in direct-seeding cultivation in rice. In this study, a backcross inbred line (BIL) population from a cross between Kasalath and Nipponbare was employed to map quantitative trait loci (QTLs) for mesocotyl elongation. A total of 5 QTLs for mesocotyl length were identified on chromosomes 1, 3, 7, 9, and 12 in 2 independent experiments. At all QTL, the Kasalath alleles contributed to an increase in mesocotyl length. Two QTLs (<I>qMel-1</I> and <I>qMel-3</I>) on chromosomes 1 and 3 were consistently detected in both experiments. To fine map the QTLs, a cross was made between 2 chromosome segment substitution lines (CSSL-6 and CSSL-15), each harboring the Kasalath allele across the <I>qMel-1</I> and <I>qMel-3</I> regions, and an F<SUB>2:3</SUB> population was developed. A two-way ANOVA indicated that no epistatic interaction was detected between the 2 QTLs in the F<SUB>2</SUB> population (<I>P</I> = 0.31). Moreover, analysis of two F<SUB>3</SUB> near-isogenic lines (NILs) derived from the same cross, indicated that the 2 QTLs act additively in distinct or complementary pathways in controlling mesocotyl elongation. Substitution mapping indicated that the <I>qMel-1</I> QTL was located between the 2 SSR markers RM5448 and RM5310, which are 3,799-kb apart, and that the <I>qMel-3</I> QTL was located between the 2 SSR markers RM3513 and RM1238, which are 6,964-kb apart. To our knowledge, this is the first report to fine-map QTLs for mesocotyl elongation and to analyze their interaction.</P><P><B>Electronic supplementary material</B></P><P>The online version of this article (doi:10.1186/1939-8433-5-13) contains supplementary material, which is available to authorized users.</P>

비신축성 직물의 고무 밴드 봉제 조건에 따른 신장 특성 분석

엄란이 ( Ran-i Eom ),이예진 ( Yejin Lee ) 한국의류학회 2021 한국의류학회지 Vol.45 No.4

This study analyzes how sewing conditions for elastic bands on woven fabrics affect elongation. The directions of the elastic bands were vertical, horizontal, vertical and horizontal crossing, and horizontal and vertical crossing. Intervals between the elastic bands were 3.0 cm and 6.0 cm. The woven fabric was tailored for the elastic band sewing using warp, weft, and bias. Consequently, it was possible to visually confirm elongation differences according to the sewing condition of the elastic bands. A detailed examination demonstrated that the horizontal or vertical placement of elastic bands tailored in a crosswise direction produces high vertical elongation and low horizontal contraction. However, elastic bands sewed in crossing directions, regardless of warp and weft directions, resulted in both high vertical elongation and high horizontal contraction. In all cases, the more elastic bands were used, the higher the horizontal elongation. In conclusion, appropriate placements of elastic bands on woven fabric increases motion convenience.

절개선을 활용한 직물의 신장변화에 관한 연구

이정숙,성수광,이인아 한국의류산업학회 2002 한국의류산업학회지 Vol.4 No.3

To propose a basic material that can improve the crumples in the knee area and can be applied as an element of garment design, the present study examined the elongation rates of the samples by differentiating the number of cutting lines according to the direction of the fabric, and then determined the puckering phenomenon by judging the conditions of the seams based on the looks of seam lines after bi-axil elongation. After the subjective evaluation on the knee areas of both the standard and modified trousers, the following conclusion was drawn : The elongation rates of the samples are: warp (3.98%)<warp1 (4.29%)<weft1 (5.30%)<weft (5.82%)<warp2 (5.68%)<bias (6.96%)<weft2 (8.64%). The samples in the warp direction: as the cutting lines increase, the elongation rate grows by 1.4%. The elongation rates of the samples in the weft direction: the sample with one cutting line has 0.52% lower rate than that in the weft direction without cutting line; that with two cutting lines has 1.68% higher rate than that running on the bias. The subjective evaluation on the knee areas: the subjects wearing the standard trousers feel more comfortable when sitting on a chair (0.2) >cross-legged (-0.2) > squatting down (-0.4); those in the modified trousers feel more comfortable when sitting on a chair (0.2) > cross-legged (0)> squatting down (-0.6). In the cross-legged posture, the modified trousers (0) has higher scores in the subjective evaluation than the standard ones (-0.2). The evaluation on the looks of needleworks in the samples with cutting lines along the direction of the fabric: weft2 (5.0)<weft1 (4.8)<warp1 (3.8)<warp2 (2.8).

Effects of Maleinized Polybutadiene on the Elongation and Impact Peel Strength of Epoxy Resins

Albin Davies,Archana Nedumchirayil Manoharan,최영선 한국접착및계면학회 2024 접착 및 계면 Vol.25 No.1

The effect of maleinized polybutadiene (MPB) on the mechanical properties of epoxy resins including adhesion strength, elongation and impact peel resistance was investigated in this study, in which MPB is an anhydride-functionalized polybutadiene prepolymer. Different molecular weights (3.1K and 5.6K) of MPB were added to diglycidyl ether bisphenol-A (DEGBA), an epoxy resin, to increase its impact peel strength and elongation. At various loading percent (5, 10, 15, 20 and 25 wt%) of MPB in the epoxy resin, significant improvements of mechanical properties were observed. According to the comparative analysis results, the modified epoxy system with 15 wt% (3.1K) MPB exhibited the highest lap shear strength, about 40% higher than that of neat epoxy. The tensile strength and elongation steadily and simultaneously increased as the loading percent of MPB increased. The impact peel strengths at low (-40°C) and room (23°C) temperatures were substantially improved by MPB incorporation into epoxy resins. Reactive and flexible MPB prepolymer seems to construct strong nano-structured networks with rigid epoxy backbones without sacrificing the tensile and adhesion strengths while increasing impact resistance/toughness and elongation properties. For higher impact peel while maintaining adhesion and tensile strengths, approximately 10–15 wt% MPB loading in epoxy resin was suggested. Consequently, incorporation of functionalized MPB prepolymer into epoxy system is an easy and efficient way for improving some crucial mechanical properties of epoxy resins.

Root hair‐specific expansins modulate root hair elongation in rice

ZhiMing, Yu,Bo, Kang,XiaoWei, He,ShaoLei, Lv,YouHuang, Bai,WoNa, Ding,Ming, Chen,Hyung‐,Taeg, Cho,Ping, Wu Blackwell Publishing Ltd 2011 The Plant journal Vol.66 No.5

<P><B>Summary</B></P><P>Root hair growth requires intensive cell‐wall modification. This study demonstrates that root hair‐specific expansin As, a sub‐clade of the cell wall‐loosening expansin proteins, are required for root hair elongation in rice (<I>Oryza sativa</I> L.). We identified a gene encoding <I>EXPA17</I> (<I>OsEXPA17</I>) from a rice mutant with short root hairs. Promoter::reporter transgenic lines exhibited exclusive <I>OsEXPA17</I> expression in root hair cells. The OsEXPA17 mutant protein (OsexpA17) contained a point mutation, causing a change in the amino acid sequence (Gly104→Arg). This amino acid alteration is predicted to disrupt a highly conserved disulfide bond in the mutant. Suppression of <I>OsEXPA17</I> by RNA interference further confirmed requirement for the gene in root hair elongation. Complementation of the <I>OsEXPA17</I> mutant with other root hair EXPAs (OsEXPA30 and Arabidopsis EXPA7) can restore root hair elongation, indicating functional conservation of these root hair EXPAs in monocots and dicots. These results demonstrate that members of the root hair EXPA sub‐clade play a crucial role in root hair cell elongation in Graminaceae.</P>