• Title/Summary/Keyword: clipping

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Arachnoid Remodeling by Clipping Technique Facilitates Surgical Maneuverability during Transsphenoidal Surgery for Pituitary Macroadenoma

  • Kim, Eui Hyun;Park, Soo Jeong;Na, Minkyun;Moon, Ju Hyung;Kim, Sun Ho
    • Journal of Korean Neurosurgical Society
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    • v.65 no.4
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    • pp.591-597
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    • 2022
  • Objective : Pituitary adenomas frequently extend into the suprasellar space. After a suprasellar tumor is removed, the superiorly extended arachnoid becomes redundant and sinks down into the intrasellar space which often hiders visualization and accessibility to the hidden space behind the evaginated arachnoid. We introduced arachnoid remodeling by clipping technique, and evaluated its usefulness and safety during TSS. Methods : Total 223 patients who underwent arachnoid remodeling with our new clipping technique were included. Redundant arachnoid was clipped along the dural edge with multiple 2.6-mm titanium clips until the redundant arachnoid membrane no longer blocked the surgical route. To check for possible deterioration of hormonal function by this technique, we assessed anterior pituitary function of 166 patients who underwent arachnoid remodeling by clipping and compared this with those of other 429 control patients. Results : Our technique greatly enhanced the accessibility and visualization of intrasellar and parasellar spaces, both of which are generally hindered by redundant arachnoid during transsphenoidal surgery (TSS). We found no difference in anterior pituitary function between a clip-assisted arachnoid remodeling group and the control group, implying that this technique does not result in hypopituitarism. Conclusion : During TSS for pituitary adenomas with suprasellar extension, arachnoid remodeling by clipping technique is very useful and convenient for the management of the redundant arachnoid membrane to enhance visualization and surgical accessibility.

Effect of nitrogen application and clipping height on the vegetative growth of Korean lawn grass (Zoysia japonica Steud.) and Manilagrass (Zoysia mat rella (L.) MERR.) during September/October (질소시용 및 예초고가 한국 잔디(Zoysia japonica Steud.) 및 금잔디(Zoysia matrella MERR.)의 생육후기 영양생장에 미치는 영향)

  • 심재성;윤익석
    • Asian Journal of Turfgrass Science
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    • v.1 no.1
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    • pp.7-17
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    • 1987
  • The experiment with two levels of nitrogen (0. and 300kg / ha / year) and two levels of clipping height (1.5cm and 4cm) was conducted on the field during the period 3 June to 23 October 1985. Clonal lines of korean lawngrass ( Zoysia japonica Steud.) and manilagrass ( Zoysia matrella ( L.) Merr.)of Daejon origin were established in June, as individual clone in rows 30cm apart with a 40cm spacing between clones, actually 4 clones each plot. The results obtained were as follows : 1. When no nitrogen was applied to korean lawngrass, leaf blade which appeared during the August / early September period remained green for a period of about 10 weeks and even leaves emerged in late September lived for 42 days. However, leaf longevity did not exceed 8 weeks as nitrogen was applied. In contrast the leaf longevity of manilagrass which emerged during the mid - August / early September period was 11 weeks and, under the nitrogen applied, 9 weeks, indicating that the life - saen of individual leaf of manilagrass may be longer than that of korean lawngrass. Meanwhile, clipping height had no effect on the leaf longevity in both grasses. 2. During the July / August period, tiller number, green leaf number and DM weight of korean lawngrass were increased significantly with fertilizer nitrogen, but were not with two levels of clipping height. This trend was reversed after late September : no effect of nitrogen was appeared. Instead, lax clipping increased tiller number, green leaf number and DM weight. Green leaves stimulated by lax clipping resulted in the occurrance of more dead leaves in late October. 3. The increase of tiller number, green leaf number, and DM weight of korean lawngrass due to nitrogen application appeared to be of significance in early September. Unlike korean lawngrass, however, this significant increase was maintained to late October when new green leaves still emerge. Clipping height had little effect on the growth of manilagrass by early September, but since then, lax clipping stimulated leaf appearance, possibly resulting in a remained green color of manilagrass turf. 4. Among the stolons outgrown until early September, the primary stolon was not influenced by nitrogen and clipping treatments to produce only 2 - 3 stolons. However, 1st branch stolon as affected by nitrogen increased significantly, so most of stolons which occurred consisted of 1st branch stolon. 5. Until early September, stolon length obtained at nil nitrogen level was chiefly caused by lengthening the primary stolons. By applying nitrogen the primary stolons of korean lawngrass was longer than 1st branch stolons when severe clipping was involved and in turn, shorter than 1st branch stolons when lax clipping was concerned. In manilagrass, 1st branch stolons were much longer than the primary stolons when turf was clipped severely but in conditions of lax clipping, there was little difference in length between primary and 1st branch stolons. 6. Stolon nodes of both korean lawngrass and manilagrass were positively influenced by nitrogen, but no particular increases by imposing clipping height treatment was marked in manilagrass. Although the stolon of korean lawngrass was grown until late october, the growth stimulated by nitrogen was not so remarkable as to exceed that a by nil N. 7. The thickness of korean lawngrass and manilagrass was greatest in late September, but that of manilagrass did not differ significantly from that in late October. 8. The response of stolon length of korean lawngrass to lax clippings was not so great in late October as to that to severe clippings. On the other hand, the positive effect of lax clippings to stolon length in m anilagrass was confirmed even in late October.

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Clipping Distortion Suppression of Directly Modulated Multi-IF-over-Fiber Mobile Fronthaul Links Using Shunt Diode Predistorter

  • Han, Changyo;Cho, Seung-Hyun;Sung, Minkyu;Chung, Hwan Seok;Lee, Jong Hyun
    • ETRI Journal
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    • v.38 no.2
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    • pp.227-234
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    • 2016
  • Herein, we demonstrate clipping distortion suppression of directly modulated multi-IF-over-fiber links using a simple shunt diode predistorter. The dynamic range of a directly modulated analog fiber optic link is limited by nonlinear distortions caused by laser-diode clipping. We investigate the link performance in the context of carrie-to-noise and distortion ratio (CNDR) and error vector magnitude (EVM) requirements when supporting LTE-A services. We also design an analog predistorter with a shunt-diode structure, and demonstrate experimentally that the predistorter has the ability to suppress clipping-induced third-order intermodulation distortions of the link by at most 14 dB. It also improves the CNDR and EVM of the 4-IF-multiplexed LTE-A carriers by 7 dB and 2.9%, respectively.

Joint Hierarchical Semantic Clipping and Sentence Extraction for Document Summarization

  • Yan, Wanying;Guo, Junjun
    • Journal of Information Processing Systems
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    • v.16 no.4
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    • pp.820-831
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    • 2020
  • Extractive document summarization aims to select a few sentences while preserving its main information on a given document, but the current extractive methods do not consider the sentence-information repeat problem especially for news document summarization. In view of the importance and redundancy of news text information, in this paper, we propose a neural extractive summarization approach with joint sentence semantic clipping and selection, which can effectively solve the problem of news text summary sentence repetition. Specifically, a hierarchical selective encoding network is constructed for both sentence-level and document-level document representations, and data containing important information is extracted on news text; a sentence extractor strategy is then adopted for joint scoring and redundant information clipping. This way, our model strikes a balance between important information extraction and redundant information filtering. Experimental results on both CNN/Daily Mail dataset and Court Public Opinion News dataset we built are presented to show the effectiveness of our proposed approach in terms of ROUGE metrics, especially for redundant information filtering.

Clinical and Angiographic Results after Treatment with Combined Clipping and Wrapping Technique for Intracranial Aneurysm

  • Suh, Sang-Jun;Kim, Sang-Chul;Kang, Dong-Gee;Ryu, Kee-Young;Lee, Hyuk-Gee;Cho, Jae-Hoon
    • Journal of Korean Neurosurgical Society
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    • v.44 no.4
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    • pp.190-195
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    • 2008
  • Objective : There have been numerous follow-up studies of patients who had ruptured or unruptured intracranial aneurysms treated by wrapping technique using various materials have been reported. Our objective was to ascertain whether our particular wrapping technique using the temporalis muscle provides protection from rebleeding and any aneurysm configuration changes in follow-up studies. Methods : Clinical presentation, the location and shape of the aneurysm, outcomes at discharge and last follow-up, and any aneurysm configuration changes on last angiographic study were analyzed retrospectively in 21 patients. Reinforcement was acquired by clipping the wrapped temporalis muscle. Wrapping and clipping after incomplete clipping was also done. Follow-up loss and non-angiographic follow-up patient groups were excluded in this study. Results : The mean age was 53 years (range 29-67), and 15 patients were female. Among 21 patients, 10 patients had ruptured aneurysms (48%). Aneurysms in 21 patients were located in the anterior circulation. Aneurysm shapes were broad neck form (14 cases), fusiform (1 case), and bleb to adjacent vessel (6 cases). Five patients were treated by clipping the wrapped temporalis, and 16 patients by wrapping after partial clipping. The mean Glasgow coma scale (GCS) at admission was 14.2. The mean Glasgow outcome scale (GOS) at discharge was 4.8, and 18 patients were grade 5. The mean period between initial angiography and last angiography was 18.5 months (range 8-44). Aneurysm size was not increased in any of these patients and configuration also did not change. There was no evidence of rebleeding in any of these treated aneurysms. Conclusion : Our study results show that wrapping technique, using the temporalis muscle and aneurysm clip(s), for intracranial aneurysm treatment provides protection from rebleeding or regrowth.

Surgical Experience of the Ruptured Distal Anterior Cerebral Artery Aneurysms

  • Lee, Jong-Young;Kim, Moon-Kyu;Cho, Byung-Moon;Park, Se-Hyuck;Oh, Sae-Moon
    • Journal of Korean Neurosurgical Society
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    • v.42 no.4
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    • pp.281-285
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    • 2007
  • Objective : Distal anterior cerebral artery (DACA) aneurysms are fragile and known to have high risks for intraoperative premature rupture and a relatively high associated morbidity. To improve surgical outcomes of DACA aneurysms, we reviewed our surgical strategy and its results postoperatively. Methods : A total of 845 patients with ruptured cerebral aneurysms were operated in our hospital from January 1991 to December 2005. Twenty-three of 845 patients had ruptured DACA aneurysms which were operated on according to our surgical strategy. Our surgical strategy was as follows; early surgery, appropriate releasing of CSF, appropriate surgical approach, using neuronavigating system, securing the bridging veins, using temporary clipping and/or tentative clipping, meticulous manipulation of aneurysm, and using micro-Doppler flow probe. Twenty of 23 patients who had complete medical records were studied retrospectively. We observed the postoperative radiographic findings and checked Glasgow Outcome Scale score sixth months after the operation. Results : Nineteen DACA aneurysms were clipped through a unilateral interhemispheric approach and one DACA aneurysm was clipped through a pterional approach. Postoperative radiographic findings revealed complete clipping of aneurysmal neck without stenosis or occlusion of parent arteries. In two patients, a residual neck of aneurysm was visualized. Seventeen patients showed good recovery, one patient resulted in moderate disability, while 2 patients died. Conclusion : With our surgical strategy it was possible to achieve acceptable surgical morbidity and mortality rates in patients with DACA aneurysms. Appropriate use of tentative clipping, temporary clipping and neuro-navigating systems can give great help for safe approach and clipping of DACA aneurysm.

Predicting Factors of Chronic Subdural Hematoma Following Surgical Clipping in Unruptured and Ruptured Intracranial Aneurysm

  • Kwon, Min-Yong;Kim, Chang-Hyun;Lee, Chang-Young
    • Journal of Korean Neurosurgical Society
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    • v.59 no.5
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    • pp.458-465
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    • 2016
  • Objective : The aim of this study is to analyze the differences in the incidence, predicting factors, and clinical course of chronic subdural hematoma (CSDH) following surgical clipping between unruptured (UIA) and ruptured intracranial aneurysm (RIA). Methods : We conducted a retrospective analysis of 752 patients (UIA : 368 and RIA : 384) who underwent surgical clipping during 8 years. The incidence and predicting factors of CSDH development in the UIA and RIA were compared according to medical records and radiological data. Results : The incidence of postoperative CSDH was higher in the UIA (10.9%) than in the RIA (3.1%) (p=0.000). In multivariate analysis, a high Hounsfield (HF) unit (blood clots) for subdural fluid collection (SFC), persistence of SFC ${\geq}5mm$ and male sex in the UIA and A high HF unit for SFC and SFC ${\geq}5mm$ without progression to hydrocephalus in the RIA were identified as the independent predicting factors for CSDH development (p<0.05). Conclusion : There were differences in the incidence and predicting factors for CSDH following surgical clipping between UIA and RIA. Blood clots in the subdural space and persistence of SFC ${\geq}5mm$ were predicting factors in both UIA and RIA. However, progression to hydrocephalus may have in part contributed to low CSDH development in the RIA. We suggest that cleaning of blood clots in the subdural space and efforts to minimize SFC ${\geq}5mm$ at the end of surgery is helpful to prevent CSDH following aneurysmal clipping.

Arachnoid Plasty to Prevent and Reduce Chronic Subdural Hematoma after Clipping Surgery for Unruptured Intracranial Aneurysm : A Meta-Analysis

  • Jang, Kyoung Min;Choi, Hyun Ho;Nam, Taek Kyun;Park, Yong Sook;Kwon, Jeong Taik
    • Journal of Korean Neurosurgical Society
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    • v.63 no.4
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    • pp.455-462
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    • 2020
  • Objective : Recent studies have reported that arachnoid plasty (ARP) using gelatin sponges with fibrin glue reduced the occurrence of chronic subdural hematoma (CSDH) following clipping surgery for unruptured intracranial aneurysm (UIA). This meta-analysis was conducted to collate further evidence for the efficacy of ARP in preventing postoperative CSDH. Methods : Data of patients who underwent clipping surgery were extracted from PubMed, EMBASE, and Cochrane Central Register of Controlled Trials by two independent reviewers. A random effects model was used to investigate the efficacy of ARP by using odd ratios (ORs) and 95% confidence intervals (CIs). A meta-regression analysis for male sex was additionally preformed. Results : Data from six studies with 1715 patients were consecutively included. Meta-analysis revealed that ARP was significantly associated with lower rates of CSDH development after surgical clipping for UIA (ARP group vs. control group : 3.2% vs. 7.2%; OR, 0.40; 95% CI, 0.18-0.93; I2=44.3%; p=0.110). Meta-regression analysis did not highlight any modifying effect of the male sex on postoperative CSDH development (p=0.951). Conclusion : This meta-analysis indicated that ARP reduced the incidence rates of CSDH following clipping surgery for UIA. If feasible, ARP would be implemented as an additional surgical technique to prevent postoperative CSDH development during surgical clipping of UIA.

Performance Evaluation of a Time- and Frequency-Domain Clipping-Based PAPR Reduction Scheme in a DVB-T System (DVB-T 시스템에서 시간 및 주파수 영역 클리핑 기반의 PAPR 감소기법의 성능평가)

  • Seo, Man-Jung;Im, Sung-Bin;Kim, Na-Hoon;Cho, Jun-Kyung
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.44 no.1
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    • pp.24-31
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    • 2007
  • DVB-T (Digital Video Broadcasting-Terrestrial) is an important multimedia broadcasting technology capable of high data-rate transmission and adopted by Europe. OFDM (Orthogonal Frequency Division Multiplexing) is the backbone technique employed in DVB-T to support multimedia services that have various bandwidths. Unfortunately, an OFDM signal has a large PAPR (Peak-to-Average Power Ratio). In this paper, we investigate the performance of a simple PAPR reduction scheme for the DVB-T system, which requires no change of a receiver structure or no additional information transmission. The approach we employed is clipping in the time and frequency domains. The time-domain clipping is carried out with a predetermined clipping level while the frequency-domain clipping is done within EVM (Error Vector Magnitude). This approach is suboptimal with lower computational complexity compared to the optimal method. The simulation results demonstrate that the proposed one is getting more effective at lower modulation levels and with more allowed constellation error.

Modified Arachnoid Plasty Reduces Chronic Subdural Hematoma after Unruptured Aneurysm Clipping : Technical Note

  • Lee, Won Jae;Nam, Taek Min;Jo, Kyung-Il;Yeon, Je Young;Hong, Seung-Chyul;Kim, Jong-Soo
    • Journal of Korean Neurosurgical Society
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    • v.61 no.6
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    • pp.761-766
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    • 2018
  • Objective : Chronic subdural hematoma (CSDH) is a rare complication of unruptured intracranial aneurysm (UIA) clipping surgery. To prevent postoperative CSDH by reducing subdural fluid collection, we applied the modified arachnoid plasty (MAP) during the UIA clipping surgery to seal the dissected arachnoid plane. Methods : This retrospective study included 286 patients enrolled from July 2012 to May 2015. We performed arachnoid plasty in all patients, with MAP used after June 17, 2014. Patients were divided into two groups (non-MAP vs. MAP), and by using uni- and multivariate analyses, baseline characteristics, and relationships with postoperative CSDH between the two groups were analyzed. The degree of preoperative brain atrophy was estimated using the bicaudate ratio (BCR) index. Results : Ten patients (3.5%) among 286 patients had postoperative CSDH after clipping. Nine (3.1%) were in the non-MAP group, and one (0.9%) was in the MAP group. The higher BCR index showed statistical significance with occurrence of postoperative CSDH in both uni- (p=0.018) and multivariate (p=0.012; odds ratio [OR], 8.547; 95% confidence interval [CI], 1.616-45.455) analyses. MAP was associated with a lower risk of postoperative CSDH (p=0.022; OR, 0.068; 95% CI, 0.007-0.683). Conclusion : This study shows that the degree of preoperative brain atrophy is associated with an increased occurrence of CSDH after clipping and that MAP could help reduce the risk of postoperative CSDH after unruptured aneurysm clipping via a lateral supraorbital approach.