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The flow diversion technique is increasingly used for reconstructive endovascular treatment of fusiform cerebral aneurysms. Double stenting with the Low-profile Visualized Intraluminal Support (LVIS) Blue stent is one of the flow diversion techniques. The aim of this study was to analyze the clinical and angiographic outcomes of LVIS Blue double stenting for fusiform cerebral aneurysms.Between March 2016 and July 2020, double LVIS Blue stenting was attempted in 25 fusiform cerebral aneurysms. Patient medical records and radiological images were carefully reviewed.The technical success rate was 100% (25/25). Six aneurysms (24.0%) were located in the anterior circulation and 19 aneurysms (76.0%) were located in the posterior circulation. Intraprocedural thromboembolic complications occurred in 1 patient (4.0%). During the follow-up period (30.8 ± 14.2 months), there were no deaths or delayed complications. The mean angiographic follow-up duration was 28.2 ± 12.8 months. Follow-up angiography revealed complete obliteration (O'Kelly-Marotta D) in 21 (84.0%) patients and near-complete obliteration (O'Kelly-Marotta C + 2 matched with Kamran-Byrne grade 3) in 2 (8.0%) patients. Two patients (8.0%) showed worsening of obliteration grades. One (4.0%) patient required retreatment. There was no significant in-stent stenosis or branch occlusion covered by stents.Double stenting using LVIS Blue stents for the treatment of fusiform cerebral aneurysms is effective and safe.

Objective: The trend in the initial severity of aneurysmal subarachnoid hemorrhage (SAH) is unclear. This study aimed to evaluate whether there was an improvement in the initial severity of SAH over time.Methods: From January 1, 2005, to December 31, 2020, we identified patients who visited the emergency department of our institution with SAH due to intracranial aneurysm rupture. We identified the Hunt Hess (HH) grade and modified Fisher grade of each patient from the medical records, and the Mann-Kendal method was used to estimate the trend of each grade system.Results: A total of 547 patients with SAH were identified. The mean age of the patients was 59.3 years (standard deviation (SD), 14.6). The mean aneurysm size was 6.9 mm (SD, 4.6 mm). The most frequent aneurysm location was the anterior communicating artery (28.7%). In the Mann-Kendal estimates for the analysis of the trend, there was no statistically significant grade throughout the HH and modified Fisher grades. Similarly, there was no improvement throughout all grades in the modified Fisher grade over time.Conclusions: The initial severity of SAH due to cerebral aneurysm rupture did not improve over time.

Objective : Stent-assisted coil embolization (SAC) has been increasingly used to treat various types of intracranial aneurysms. Delayed thromboembolic complications are major concerns regarding this procedure, so dual antiplatelet therapy with aspirin and clopidogrel is needed. However, clinicians vary the duration of dual antiplatelet therapy after SAC, and no randomized study has been performed. This study aims to compare the safety and efficacy of long-term (12 months) dual antiplatelet therapy and shortterm dual antiplatelet therapy (6 months) after SAC for patients with unruptured intracranial aneurysms (UIAs).Methods : This is a prospective, randomized and multicenter trial to investigate the optimal duration of dual antiplatelet therapy after SAC in patients with UIAs. Subjects will receive dual antiplatelet therapy for 6 months (short-term group) or 12 months (longterm group) after SAC. The primary endpoint is the assessment of thromboembolic complications between 1 and 18 months after SAC. We will enroll 528 subjects (264 subjects in each group) and perform 1 : 1 randomization. This study will involve 14 topperforming, high-volume Korean institutions specializing in coil embolization.Results : The trial will begin enrollment in 2022, and clinical data will be available after enrollment and follow-up.Conclusion : This article describes that the aim of this prospective randomized multicenter trial is to compare the effect of short-term (6 months) and long-term (12 months) dual antiplatelet therapy on UIAs in patients undergoing SAC, and to find the optimal duration.

There are few reports on the preventative value of intensive blood pressure (BP) management for stroke in the literature since the new criteria for hypertension (HTN) were announced by the American College of Cardiology/American Heart Association in 2017. To identify the optimal BP for the primary prevention of stroke in a healthy population aged between 19 and 65 years, we conducted a 10-year observational study on the risk of stroke, subclassified as hemorrhagic stroke (hSTK) and ischemic stroke (iSTK), according to BP categories (e.g., low-normal BP, high-normal BP, elevated BP, stage 1 HTN and stage 2 HTN) using the National Health Insurance Service Database. Of the 8,327,751 participants who had a health checkup in 2008, 949,551 were ultimately enrolled in this study and observed from 2009 to 2018. The risk of hSTK was significantly increased from stage 2 HTN (adjusted hazard ratio (AHR) 3.036 [95% confidence interval (CI), 2.159–4.252]) in men and from stage 1 HTN (AHR 2.972 [95% CI, 2.256–3.897]) in women. The risk of iSTK was significantly increased among both men (AHR 1.404 [95% CI, 1.164–1.693]) and women (AHR 2.012 [95% CI, 1.603–2.526]) with stage 1 HTN. The risk of overall stroke was significantly increased in men (AHR 1.386 [95% CI, 1.180–1.629]) and women (AHR 2.363 [95% CI, 1.973–2.830]) from stage 1 HTN. Therefore, for the primary prevention of overall stroke, adults under the age of 65 should manage their BP from stage 1 HTN.

A 68-year-old male patient was transferred to the emergency department after a passerby found him lying on the road with a bicycle. He had been diagnosed with neurolymphomatosis in 2006 and had an Ommaya reservoir targeted to the right lateral ventricle via the right Kocher’s point for chemotherapy. His initial mental status was stuporous. Brain computed tomography (CT) showed multiple traumatic injuries. Seven days after admission, bilateral subdural hygroma (SDG) developed. We performed CT cisternography. The contrast was directly injected into the Ommaya reservoir and CT images were obtained. On cisternography, contrast leakage points were identified from the Ommaya reservoir. The patient underwent surgery for Ommaya reservoir removal and occlusion of the permanent tract of the Ommaya reservoir. This case shows a rare etiology of traumatic SDG and demonstrates the usefulness of CT cisternography to determine cerebrospinal fluid leakage from an implant.

Objective The treatment of multiple intracranial aneurysms (MIAs) involves various modalities and sometimes requires staged operations. This study aimed to prove the efficacy and safety of one-stage multiple craniotomies (OSMC) for multiple cerebral aneurysms. Methods We retrospectively reviewed the medical records of the patients who underwent treatment for intracranial aneurysms between May 2003 and April 2020. The surgical results, complications, and lengths of hospital stay were compared between the patients who underwent OSMC and those who underwent multi-stage multiple craniotomies (MSMC). Results The demographic characteristics of the OSMC and MSMC groups (n=82 and 43, respectively) were similar. There were no statistically significant differences between the two groups when the amount of blood transfused, complications, and surgical results were compared (p=n.s. for all); however, the operation time and hospitalization period (353.9 min vs. 490.3 min and 12.3 days vs. 21.8 days, respectively; p=0.001 for both) were shorter in the OSMC group. The treatment cost (17,000 USD vs. 22,000 USD, p=0.001) was lower in the OSMC group. Conclusions OSMC for aneurysm clipping in patients with MIAs is a relatively safe and economical method. Furthermore, it has good clinical outcomes. This new surgical method is worthwhile in that it can be applied to patients who are afraid to undergo multiple surgeries, and we suggest it is an efficient, low-cost option for the treatment of MIAs.

There arefew reports on the preventative value of intensive blood pressure (BP) management for stroke, especially hemorrhagic stroke (hSTK),after new criteria for hypertension (HTN) were announced by theAmerican College of Cardiology/American Heart Association in 2017. To identify the optimal BP for the primary prevention of hSTK in a healthy population aged between 20 and 65 years, we conducted a 10-yearobservational study on the risk of hSTK, subclassified as intracerebral hemorrhage (ICH) and subarachnoid hemorrhage (SAH) according to BP categories (e.g.,low normal BP, high normal BP, elevated BP, stage 1 HTN and stage 2 HTN) using the National Health Insurance Service Database. Of the 8,325,579 participants who had a health checkup in 2008, 947,378 were ultimately enrolled in this study and observed from 2009 to 2018. The risk of ICH was significantly increased from stage 2 HTN (adjusted hazard ratio (AHR) 2.002 [95% confidence interval (CI) 1.203-3.332]) and stage 1 HTN (AHR 2.021 [95% CI, 1.251-3.263]) in men and women, respectively. The risk of SAH was significantly increased among both men (AHR 1.637 [95% CI, 1.066-2.514]) and women (AHR 4.217 [95% CI, 2.648-6.715]) from stage 1 HTN. The risk of hSTK was significantly increased among men with stage 2 HTN (AHR 3.034 [95% CI, 2.161-4.260]) and women with stage 1 HTN (AHR 2.976 [95% CI, 2.222-3.986]).Therefore, for the primary prevention of hSTK, including ICH and SAH, adults under the age of 65 should manage their BP from stage 1 HTN.

Objective : Placement of a single transverse stent via the nondominant A1 across the anterior communicating artery (AComA) into the contralateral A2 can provide sufficient neck coverage for wide-necked bifurcation AComA aneurysms. The authors described the feasibility, safety and long-term outcomes of this technique.Methods : Between January 2015 and February 2018, placement of a single transverse stent via the nondominant A1 was attempted in 17 wide-necked bifurcation AComA aneurysms. The authors reviewed the medical records and radiological studies.Results : The technical success rate was 94.1% (16/17). Periprocedural thromboembolic complications occurred in one patient (6.3%) without permanent neurological deficits. The mean clinical follow-up duration was 39.9±9.8 months. No deaths or delayed thromboembolic complications occurred. The mean angiographic follow-up duration was 38.9±9.8 months. The immediate and final follow-up complete occlusion rates were 87.4 and 93.7%, respectively. There was no recanalization during the follow-up period.Conclusion : Placement of a single transverse stent via the nondominant A1 across the AComA into the contralateral A2 is a feasible and relatively safe endovascular technique for the treatment of wide-necked bifurcation AComA aneurysms, with good long-term occlusion rates and a reasonable complication rate, if only the nondominant A1 is applicable.

Objective:This study aimed to demonstrate the effectiveness of nonemergent extracranial-to-intracranial bypass (EIB) in symptomatic chronic large artery atherosclerotic stenosis or occlusive disease (LAA) through quantitative analysis of computed tomography perfusion (CTP) parameters using RAPID software. Methods: We retrospectively analyzed 86 patients who underwent nonemergent EIB due to symptomatic chronic LAA. CTP data obtained preoperatively, immediately postoperatively (PostOp0), and 6 months postoperatively (PostOp6M) after EIB were quantitatively analyzed through RAPID software, and their association with intraoperative bypass flow was assessed. The clinical outcomes, including neurologic state, incidence of recurrent infarction and complications, were also analyzed. Results: The time-to-maximum (Tmax) >8 s, >6 s and >4 s volumes decreased significantly at PostOp0 and up through PostOp6M (preoperative, 5, 51, and 223 ml (median), respectively; PostOp0, 0, 20.25, and 143 ml, respectively; PostOp6M, 0, 7.5, and 148.5 ml, respectively; p6 s and >4 s volumes was significantly correlated with the bypass flow at PostOp0 and PostOp6M (PostOp0, r=0.367 (p=0.001) and r=0.275 (p=0.015), respectively; PostOp6M r=0.511 (pConclusion: Nonemergent EIB under strict operation indications can be a feasible treatment for symptomatic, hemodynamically compromised LAA patients.

This study aimed to demonstrate the effectiveness of urgent extracranial-to-intracranial bypass (EIB) in acute ischemic stroke (AIS) through quantitative analysis of computed tomography perfusion (CTP) results using RAPID software. We retrospectively analyzed 41 patients who underwent urgent EIB for AIS under strict operation criteria. The quantitative data from CTP images were reconstructed to analyze changes in pre- and postoperative perfusion status in terms of objective numerical values using RAPID software. Short- and long-term clinical outcomes, including complications and neurological status, were also analyzed. Postoperatively, the volume of time-to-max (Tmax) > 6 s decreased significantly; it continued to improve significantly until 6 months postoperatively (preoperative, 78 ml (median); immediate postoperative, 23 ml; postoperative 6 months, 7 ml; p = 0.000). Ischemic core-penumbra mismatch volumes were also significantly improved until 6 months postoperatively (preoperative, 72 ml (median); immediate postoperative, 23 ml; postoperative 6 months, 5 ml; p = 0.000). In addition, the patients’ neurological condition improved significantly (p

The recurrence rate of posterior communicating artery (Pcom) aneurysms after endovascular treatment (EVT) is higher than that for aneurysms located in other sites. However, it is still unclear what mechanisms are responsible for the recanalization of cerebral aneurysms. In this investigation, we compared hemodynamic factors related with recanalization of Pcom aneurysms treated by endoluminal coiling using computational fluid dynamics (CFD) with high-resolution three-dimensional digital subtraction angiography images. Twenty patients were enrolled. A double-sinogram acquisition was performed with and without contrast injection after coil embolization to get true blood vessel lumen by relatively complementing the first sinogram with the second. Adaptive Cartesian meshing was performed to produce vascular wall objects for CFD simulation. The boundary condition for inlet (ICA) was set for dynamic velocity according to the cardiac cycle (0.8 s). Hemodynamic parameters were recorded at two specific points (branching point of Pcom and residual sac). The peak pressure, peak WSS, and oscillatory shear index (OSI) were recorded and analyzed. The median age was 61.0 years, and 18 patients (90%) were female. During a median follow-up of 12 months, seven (35%) treated aneurysms showed recanalization. The median aneurysm volume was significantly higher, and aneurysm height and neck sizes were significantly longer in the recanalization group than those in the stable group. At the branching point of the Pcom, the peak pressure, peak WSS, or OSI did not significantly differ between the two groups. The only statistically significant hemodynamic parameter related with recanalization was the OSI at the aneurysm point. Multivariate logistic regression showed that with an increase of 0.01 OSI at the aneurysm point, the odds ratio for the aneurysm recanalization was 1.19. A higher OSI is related with recanalization after coil embolization for a Pcom aneurysm.

Objective The treatment of choice for acute ischemic stroke with large vessel occlusion is intra-arterial thrombectomy. The extracranial-to-intracranial (EC-IC) bypass was relatively devaluated; however, recent studies have shown that this surgery can be helpful when performed for a highly selective patient group. Methods We analyzed 41 patients who underwent urgent EC-IC bypass at the Seoul National University Bundang Hospital after being selected using strict operation criteria and retrospectively reviewed the effectiveness and safety of the surgery. In particular, quantitative data from perfusion computed tomography images were reconstructed to analyze the changes in pre- and postoperative perfusion status in terms of objective numerical values. We also clinically assessed the patients’ neurological outcome and complication rates. Results Immediate postoperatively, the volume of time-to-max (Tmax) > 6 second decreased significantly; it continued to improve significantly until 6 months postoperatively (preoperative, 89 ml; immediate postoperative, 21.5 ml; postoperative 6 months, 10.5 ml). Ischemic core-penumbra mismatch volumes were also significantly improved until 6 months postoperatively (preoperative, 77 ml; immediate postoperative, 21 ml; postoperative 6 months, 5.5 ml). Other perfusion parameters, such as Tmax > 10 s, Tmax > 8 s, and Tmax > 4 s also showed statistically significant improvement. In addition, the patient's neurological condition significantly improved. The surgical complication rate in this study was similar to those in previous studies. The predictors of good postoperative neurological condition were the patient's preoperative condition and perfusion status of the patient immediately postoperatively. Conclusion Emergent EC-IC bypass can be useful for patients with acute ischemic stroke with large vessel occlusion ineligible for IAT if surgery is performed well after applying the strict surgical indications.

Background We aimed to analyze outcomes of clipping and coiling in treating unruptured intracranial aneurysms (UIAs) in elderly patients and to identify the age at which perioperative risk increases based on national cohort data in South Korea. Methods The incidence of perioperative intracranial hemorrhage (ICRH), perioperative cerebral infarction (CI), mortality, and moderate to severe disability data of the patients who underwent coiling or clipping for UIAs were retrieved. Estimated breakpoint (EBP) was calculated to identify the age at which the risk of treatment increases. Results A total of 38,207 patients were treated for UIAs. Among these, 22,093 (57.8%) patients underwent coiling and 16,114 (42.2%) patients underwent clipping. The incidence of ICRH, requiring a secondary operation, within 3 months in patients ≥ 65 years that underwent coiling and clipping was 1.13% and 4.81%, respectively, and that of both groups assessed were significantly higher in patients ≥ 75 years (coiling, P = 0.013, relative risk (RR) 1.81; clipping, P = 0.015) than younger patients. The incidence of CI within 3 months in patients aged ≥ 65 was 13.90% and 9.19% in the coiling and clipping groups, respectively. The incidence of CI after coiling in patients aged ≥ 75 years (P < 0.001, RR 1.96) and after clipping in patients aged ≥ 70 years (P < 0.001, RR 1.76) was significantly higher than that in younger patients. The mortality rates within 1 year in patients with perioperative ICRH or CI were 2.41% and 3.39% for coiling and clipping groups, respectively, in patients ≥ 65. These rates increased significantly at age 70 in the coiling group and at age 75 for the clipping group (P = 0.012 and P < 0.001, respectively). Conclusion The risk of treatment increases with age, and this risk increases dramatically in patients aged ≥ 70 years. Therefore, the treatment decisions in patients aged ≥ 70 years should be made with utmost care., Graphical Abstract

Objective To analyze the angiographic features and clinical course, including treatment outcomes and the natural course, of fusiform middle cerebral artery aneurysms (FMCAAs) according to their location, size, and configuration. Methods We reviewed the literature on adult cases of FMCAAs published from 1980 to 2018; from 25 papers, 112 FMCAA cases, for which the location, size, and configuration could be identified, were included in this study. Additionally, 33 FMCAA cases in our hospital were included, from which 16 were assigned to the observation group. Thus, a total of 145 adult FMCAA cases were included. We classified the FMCAAs according to their location (l-type 1, beginning from prebifurcation; l-type 2, beginning from bifurcation; l-type 3, beginning from postbifurcation), size (small

BackgroundThe role of the inhibition rate of VerifyNow in assessing the thromboembolic risk of coil embolization for unruptured intracranial aneurysms is unclear.ObjectiveTo carry out a retrospective study to determine whether the inhibition rate could provide additional help in predicting thromboembolic events when it was used for patients with a P2Y12 reaction unit (PRU) level of 220 or lower.MethodsPatients who underwent coil embolization for unruptured aneurysms with an appropriate PRU level (PRU 220 or lower) between January 1, 2015 and December 31, 2018 were analyzed. A total of 954 patients with 1020 aneurysms were included in this study. The primary outcome was the thromboembolic events occurring within 30 days after coil embolization. The receiver operating characteristic (ROC) curve and the area under the curve (AUC) were obtained to determine the quantitative predictive ability of the inhibition rate. The optimal cut-off value was derived using the Youden index.ResultsThromboembolic events developed in 11 patients (1.08% of 1020 procedures). The AUC of the ROC curve was 0.83. The optimal cut-off value of the inhibition rate derived using the maximum Youden index was 22.0%. A sensitivity test using a multiple logistic regression analysis demonstrated that the inhibition rate was a significant variable for predicting thromboembolic events.ConclusionsThe inhibition rate can be used to determine high thromboembolic risks for patients with PRU levels of 220 or lower. The optimal cut-off value of the inhibition rate was 22.0% when the PRU level was 220 or less.

The treatment of multiple intracranial aneurysms (MIAs) involves various modalities and sometimes requires staged operations. This study aimed to prove the efficacy and safety of one-stage multiple craniotomies (OSMC) for multiple cerebral aneurysms. We retrospectively reviewed the medical records of the patients who underwent surgical clipping of an intracranial aneurysm at Seoul National University Bundang Hospital between 2003 and April 2020. The surgical results, complications, and lengths of hospital stay were compared between the patients who underwent OSMC and those who underwent multi-stage multiple craniotomies (MSMC). The demographic characteristics of the OSMC and MSMC groups (n = 82 and 43, respectively) were similar. There were no statistically significant differences between the two groups when the amount of blood transfused, complications, and surgical results were compared (p = 0.925, p = 0.528, and p = 0.898, respectively); however, the operation time and hospitalization period (353.9 min vs. 490.3 min and 12.3 days vs. 21.8 days, respectively; p

This paper presents a novel method to prevent blockages by embolic microspheres in catheter channels by using convex air bubbles attached to the channels&rsquo, inner wall surface. The clogging by microspheres can occur by the arching of the microspheres in the catheter. A few studies have been done on reducing the blockage, but their methods are not suitable for use with embolic catheters. In this study, straight catheter channels were fabricated. They had cavities to form convex air bubbles, additionally, a straight channel without the cavities was designed for comparison. Blockage was observed in the straight channel without the cavities, and the blockage arching angle was measured to be 70&deg, while no blockage occurred in the cavity channel with air bubbles, even at a geometrical arching angle of 85&deg, The convex air bubbles have an important role in preventing blockages by microspheres. The slip effect on the air bubble surface and the centrifugal effect make the microspheres drift away from the channel wall. It was observed that as the size of the cavity was increased, the drift distance became larger. Additionally, as more convex air bubbles were formed, the amount of early drift to the center increased. It will be advantageous to design a catheter with large cavities that have a small interval between them.

BackgroundThe long-term outcomes of endovascular coiling and surgical clipping for the treatment of unruptured intracranial aneurysms are unclear.MethodsWe performed a nationwide retrospective cohort study using claims data from the Korean Health Insurance Review and Assessment Service on patients undergoing surgical clipping or endovascular coiling from 2008 to 2014. Inverse probability treatment weighting for average treatment effect on the treated and the multiple imputation method were used to balance covariates and handle missing values. The primary outcome was all-cause mortality at 7 years.ResultsWe identified 26 411 patients of whom 11 777 underwent surgical clipping and 14 634 underwent endovascular coiling. After adjustment with the use of inverse probability treatment weighting for average treatment effect on the treated, all-cause mortality rates at 7 years were 3.8% in the endovascular coiling group and 3.6% in the surgical clipping group (HR 1.05; 95% CI 0.86 to 1.28; P=0.60, log-rank test). The adjusted probabilities of aneurysm rupture at 7 years were 0.9% after endovascular coiling and 0.7% after surgical clipping (HR 0.9; 95% CI 0.61 to 1.34; P=0.63, log-rank test). The probabilities of retreatment at 7 years after adjustment were 4.9% in the endovascular coiling group and 3.2% in the surgical clipping group (HR 1.52; 95% CI 1.28 to 1.81; PConclusionsAll-cause mortality at 7 years was similar between the elective surgical clipping and endovascular coiling groups in patients with unruptured aneurysms who had no history of subarachnoid hemorrhage due to aneurysm rupture.

Background The number of endovascular treatment procedures performed for cerebral aneurysms has markedly increased. However, little is known about the annual effective radiation dose to medical staff in neurointervention fields. We performed a retrospective observational study to investigate the real-time radiation dose to surgeons, nurses, anesthesiologists, and radiologic technologists during endovascular treatment of intracranial aneurysms. Methods We measured the real-time radiation doses for 2 weeks using standard and reinforced protection, during which 28 procedures were performed, including 23 coil embolizations for unruptured intracranial aneurysms. Four procedures were excluded because of an inadequately equipped sensor, which resulted in inappropriate data collection. The procedure time was defined from intubation to extubation. Five RaySafe i2 detectors were installed at the chest level of the operator, attending nurse, radiologic technologist, and anesthesiologist and just inside the front door of the hybrid operating room. Results The median doses per session with standard protection to the operator, attending nurse, anesthesiologist, and radiologic technologist were 11.16, 2.60, 4.76, and 1.93 μSv, respectively. The dose to the operator, attending nurse, and anesthesiologist had decreased to 6.63, 0.39, and 1.52 μSv under reinforced protection, respectively. However, the session dose for the radiologic technologist had increased to 3.12 μSv. Conclusions We confirmed the differences in the amount of radiation exposure for different roles. An additional lead screen, which provided more effective protection on the operator side, was proved effective for attenuating radiation exposure during endovascular treatment. All personnel involved in the hybrid operating room were exposed to acceptable effective doses.

The purpose of this study is to examine material performance of fiber reinforced cement composite for mass production. It is necessary to manufacture SHCC(Strain Hardening Cement Composite) by batch plant for field application and mass production. For the study, a mock-up test of SHCC manufactured in the batch plant was conducted, and the performance was compared with SHCC manufactured in the laboratory. Assessment items were freshness and hardening properties. Specifically, direct tensile test machine was used for performance verification of SHCC. As a result, there was a tendency of less satisfactory fiber dispersion and performance of strain hardening compared with the performance of SHCC manufactured in the laboratory. To address this, dry mixing and mortar mixing time should be increased compared to laboratory mixing, and injection time of an agent such as a water reducing agent should be properly controlled according to mixing combination, or the capacity to secure dispersion and homogeneity of material.

To investigate the effect of hard segment content on ionic conductivities of poly(ether urethane) (PEU)-based solid polymer electrolytes (SPEs), PEUs containing 20, 40, 60, 80, and 100 wt.% of hard segment content were synthesized. Also we introduced polymer-in-salt system with ion-hopping mechanism contrary to traditional salt-in-polymer system with segmental motion mechanism and investigated the effect of hard segment of PEU on ionic conductivities by A.C. impedance, FT-IR, DSC, and SEM. And it could be known that hydrogen bonding of urethane group influenced the ionic conductivities of PEU-based SPE. PEU-based SPE containing 70 wt.% of salt and 20 wt.% of hard segment showed the highest ionic conductivity of 2.95 × 10−5 S/cm at room temperature.

In this paper, we propose a thin polysilicon strain gauge for the measurement of strain in structural elements. Metal-foil strain gauges are commonly used for such measurements even though polysilicon strain gauges have better sensitivity. However, the proposed polysilicon strain gauge can be applied to structural elements because the strain gauge element is separated from the silicon wafer, due to the small size and low thickness of the proposed gauge. A microelectromechanical system fabrication process of the poly-silicon strain gauge and an inorganic bonding process with a metal substrate have been established. An inorganic bonder-glass frit-was used since the commonly used organic bonders exhibit plastic behavior. Subsequently, the performance of polysilicon strain gauges glass-frit-bonded onto metal cantilever beams was evaluated. The results demonstrate that the resistance increases linearly with tensile stress while it decreases with compressive stress. The gauge factor, which represents the sensitivity of the strain gauges, was 34.0. The resistance decreases linearly with temperature with a temperature coefficient of resistance (TCR) of -328 ppm/°C. The TCR is influenced by two factors-differences in the thermal expansion of the metal cantilever beam and silicon strain gauge and the thermionic emission of the carriers. In this study, the resistance change due to thermionic emission was more effective than that by thermal expansion. The nonlinearity and hysteresis values were 0.21% FS and 0.17 % FS, respectively; this is lower than those of conventional metal-foil strain gauges. Hence, our proposed strain gauge is useful for the measurement of the strain of structural elements.

In this paper, we propose a sensor design by using a polysilicon strain gauge bonded to a metal diaphragm. The fabrication process of the thin polysilicon strain gauges having thicknesses of was established using conventional MEMS technologies; further, the technique of glass frit bonding of the polysilicon strain gauge to the stainless steel diaphragm was established. Performance of the polysilicon strain gauge bonded to the metal cantilever beam was evaluated. The gauge factor, temperature coefficient of resistance (TCR), nonlinearity, and hysteresis of the polysilicon strain gauge were measured. The results demonstrate that the resistance increases linearly with tensile stress, while it decreases with compressive stress. The value of the gauge factor, which represents the sensitivity of strain gauges, is 34.0; this value is about 7.15 times higher than the gauge factor of a metal-foil strain gauge. The resistance of the polysilicon strain gauge decreases linearly with an increase in the temperature, and TCR is . Further, nonlinearity and hysteresis are 0.21 % FS and 0.17 % FS, respectively.

A critical issue in the use of TCAMs for packet classification is how to efficiently represent rules with ranges, known as range matching. A range-matching ternary content addressable memory (RM-TCAM) including a highly functional range-matching cell (RMC) is presented in this paper. By offering various range operators, the RM-TCAM can reduce storage expansion ratio from 4.21 to 1.01 compared with conventional TCAMs, under real-world packet classification rule sets, which results in reduced power consumption and die area. A new pre-discharging match-line scheme is used to realize high-speed searching in a dynamic match-line structure. An additional charge-recycling driver further reduces the power consumption of search lines. Simulation results of a 256times64-bit range-matching TCAM, when implemented in the 0.13-mum CMOS technology, achieves a 1.99-ns search time with an energy efficiency of 1.26 fJ/bit/search. While a TCAM including range encoding approach requires an additional SRAM or DRAM, the RM-TCAM can improve storage efficiency without any extra components as well as reduce the die area.

In this study, highly ordered AAO (Anodic Aluminum Oxide) with nanopores was prepared by commercial grade Al substrate containing 3.5 wt.% impurities through two step anodizing method. Nanopores of prepared AAO arrays were used as templates for preparing nanofiber. was deposited by using DP (deposition-precipitation) method into AAO pores to grow nanofiber. Au particles were loaded on this nanofiber which was grown vertically. Prepared 2 wt.% nanofiber was characterized by XRD, SEM and Raman. The crystal structure was analyzed by the XRD. SEM was used to observe pore size and pore wall thickness. Photocatalytic activity of co-oxidation was compared with and nanofiber on AAO arrays.

This paper describes the design and the implementation of a fully integrated 10 Gb Ethernet transceiver in a 0.13-/spl mu/m CMOS process using only a 1.2 V supply. A coarse control algorithm that combines a voltage range monitoring circuit with a frequency lock detector provides a robust operation against process, voltage, and temperature (PVT) variations for a VCO with a ring oscillator. With the use of a blind oversampling DPLL architecture, four channels of XAUI transceivers can share a single PLL, eliminating the clock synchronization problem between channels. Also, the total number of clock domains for the entire chip is reduced to three, making the integration of the XAUI with the 10G transceiver much simpler. The test chip consumes 898 mW from a 1.2 V supply.

Stability result is obtained for the approximation of the stationary Stokes problem with nonconforming elements proposed by Douglas et al (1) for the velocity and discontinuous piecewise constants for the pressure on quadrilateral elements. Optimal order H 1 and L 2 error estimates are derived.

Solid polymer electrolytes (SPEs) have good safety for lithium battery compared to liquid electrolytes, but they have low ionic conductivity. To solve the problem, the polymer-in-salt system was introduced which has higher ionic conductivity than salt-in-polymer system. However, polymer-in-salt system has disadvantages that are poor mechanical properties with increasing salt concentration. In this study, networked polymer electrolytes consisting of poly(hydroxyethyl methacrylate) (P(HEMA)), lithium triflate (LiCF3SO3, LiTf) and hydrochloric acid (HCl) were prepared. And the electrochemical and mechanical properties of P(HEMA) based SPEs were investigated by using ac impedance analyzer and universal testing machine, respectively.

Solid polymer electrolytes (SPEs) are an excellent alternative to liquid electrolytes due to their non-volatility, low toxicity, and high energy density. In this study, a SPE having the ion transport mechanism decoupled from segmental motion of a polymer based on poly(vinyl alcohol) (PVA) containing the salt lithium trifluoromethane sulfonate (LiCF3SO3, LiTf) has been prepared to overcome the low ionic conductivity of traditional SPEs at room temperature. PVA has a high glass transition temperature (358 K) and good mechanical properties, and despite being atactic, it can crystallize, especially if highly hydrolyzed. From an ac impedance analysis, it was found that the ionic conductivity of the PVA-based SPE increased with increasing salt concentration. In particular, a dramatic increase was observed between 40 and 50 wt% of salt. The ionic conduction mechanism of the PVA-based SPE is proposed based on intensive study using FT-IR spectroscopic measurements, XRD and AFM. Through measurements of linear sweep voltammetry (LSV) and cyclic voltammetry (CV), it is also found that the SPE with PVA and LiCF3SO3 has good electrochemical stability.

A range-matching TCAM using the proposed range-matching cell increases storage efficiency by up to 2.5 times compared to a conventional TCAM. In addition, charge recycling with the proposed static TCAM cell can reduce the search-line power. The 512 times 144b prototype chip, fabricated in a 1.2V 0.13mum CMOS process, achieves a 4.8ns search time at 0.59fJ/b/search

A 10 Gb Ethernet transceiver chip integrated with 10 Gb/s serial and quad 3.125 Gb/s XAUI interfaces is implemented in 0.13 /spl mu/m CMOS and dissipates 898 mW from 1.2 V. A digital coarse control algorithm for VCOs reduced the VCO gains for noise immunity. A blind oversampling technique enabled synthesis of the XAUI interface.

Objective This study was performed to assess the postoperative pain of brain tumor patients who underwent elective craniotomy and to evaluate the factors associated with pain intensity. Methods From January 2010 to December 2011, 47 patients with newly diagnosed brain tumors who underwent craniotomy were enrolled. The postoperative pain status was assessed daily until discharge using the visual analogue scale (VAS). Results The study participants comprised of 22 males and 25 females with ages ranging from 18-76 years (median age, 50 years). Patients were divided into two groups: the painful group included patients who had a VAS score of more than 3 during their hospital stay after the craniotomy, and the tolerable group included patients who had a VAS score of 1 to 3 during their hospital stay. There were no differences between the two groups in terms of age, sex, location of surgery, history of diabetes, hypertension and smoking, body mass index, and hospital stay. Univariate analysis revealed that operating time, length of wound, head fixation, and perioperative administration of opioid were not associated with the intensity of postoperative pain. Daily assessment of VAS revealed the two peaks of pain on the operation day and the 4th postoperative day. The intensity of pain during the ambulation period was higher than that during intensive care unit (ICU) stay. Conclusion Pain following elective craniotomy for brain tumor removal is insufficiently managed, especially after discharge from the ICU. More attention needs to be paid to patients' pain throughout the hospital stay.

Split cord malformations (SCMs) usually present in childhood, and are rarely reported in adults. And also, a cervicothoracic SCM associated with tethered cord syndrome has very rarely been reported in the literature. We report a case of SCM associated with tethered cord and spina bifida in an adult. This report describes the case of a 34-year-old woman who presented for evaluation of neck pain, back pain, and intermittent paraparesis of several months duration. The MRI and CT showed a SCM at the cervicothoracic level and a fibrous septum at the thoracic level. She underwent surgery for the SCM and tethered cord syndrome, and was followed for 7 years. Patient presented complete recovery in the follow-up. The authors discuss this unusual lesion and describe the anatomical relationship of the level of cord duplication and fibrous septum.