Modeling of RC shear walls using shear spring and fiber elements for seismic performance assessment

Reinforced concrete shear wall is one of the most effective members during severe lateral loads especially in earthquakes and winds. Extensive researches, both analytical and experimental, have been carried out to study the behavior of reinforced concrete (RC) shear walls. Predicting inelastic response of RC walls and wall systems requires accurate, effective, and robust analytical model that incorporate important material characteristics and behavioral response features. In this study, a modeling method using fiber and spring elements is developed to capture inelastic responses of an RC shear wall. The fiber elements and the spring reflect flexural and shear behaviors of the shear wall, respectively. The fiber elements are built by inputting section data and material properties. The parameters of the shear spring that represent strength and stiffness degradation, pinching, and slip are determined based on analysis results from a detailed finite element method (FEM) model. The reliability of the FEM analysis program is verified. The applicability of the proposed modeling method is investigated by performing inelastic dynamic analyses for reference buildings with various aspect ratios of shear walls

Modeling of RC shear walls using shear spring and fiber elements for seismic performance assessment

Reinforced concrete shear wall is one of the most effective members during severe lateral loads especially in earthquakes and winds. Extensive researches, both analytical and experimental, have been carried out to study the behavior of reinforced concrete (RC) shear walls. Predicting inelastic response of RC walls and wall systems requires accurate, effective, and robust analytical model that incorporate important material characteristics and behavioral response features. In this study, a modeling method using fiber and spring elements is developed to capture inelastic responses of an RC shear wall. The fiber elements and the spring reflect flexural and shear behaviors of the shear wall, respectively. The fiber elements are built by inputting section data and material properties. The parameters of the shear spring that represent strength and stiffness degradation, pinching, and slip are determined based on analysis results from a detailed finite element method (FEM) model. The reliability of the FEM analysis program is verified. The applicability of the proposed modeling method is investigated by performing inelastic dynamic analyses for reference buildings with various aspect ratios of shear walls

Room-temperature polariton lasing in quantum heterostructure nanocavities

Controlling light-matter interactions in solid-state systems has motivated intense research to produce bosonic quasi-particles known as exciton-polaritons, which requires strong coupling between excitons and cavity photons. Ultra-low threshold coherent light emitters can be achieved through lasing from exciton-polariton condensates, but this generally requires sophisticated device structures and cryogenic temperatures. Polaritonic nanolasers operating at room temperature lie on the crucial path of related research, not only for the exploration of polariton physics at the nanoscale but also for potential applications in quantum information systems, all-optical logic gates, and ultra-low threshold lasers. However, at present, progress toward room-temperature polariton nanolasers has been limited by the thermal instability of excitons and the inherently low quality factors of nanocavities. Here, we demonstrate room-temperature polaritonic nanolasers by designing wide-gap semiconductor heterostructure nanocavities to produce thermally stable excitons coupled with nanocavity photons. The resulting mixed states of exciton-polaritons with Rabi frequencies of approximately 370 meV enable persistent polariton lasing up to room temperature, facilitating the realization of miniaturized and integrated polariton systems

Investigation of transient eye closure evoked with bright light in the patients with intermittent exotropia

Background This study aimed to present a simple method for evaluating transient eye closure (TEC) evoked by bright light and find the agreement between TEC and photosensitivity. We also assessed the associated factors with TEC in the patients with intermittent exotropia (IXT). Methods In this retrospective study, IXT patients were exposed to different brightness: darkness, low-intensity white light, and high-intensity white light using a near-infrared camera vision monitor system (Mon CV3, Metrovision, France). TEC was considered to be present if the subject closed his or her eyes immediately, and for more than half of the scotopic lid fissure distance in response to the high-intensity or low-intensity photopic stimulus of light, compared with lid fissure distance in the scotopic phase. We assessed the presence of photosensitivity using a questionnaire and evaluated the agreement between TEC and photosensitivity. We also investigated the sensory fusion, motor fusion, and pupil dynamic components for the existence of TEC in IXT patients. Results Sixty-one patients with IXT were included. With the new method to evaluate TEC under different light intensities, 27 (44.3%) of the 61 IXT patients showed TEC, and 34 (55.7%) did not demonstrate TEC. TEC under high-intensity white light had a strong correlation with self-reporting photosensitivity (r = 0.77). The smaller angle of deviation at near was associated with the presence of TEC, with statistical significance (p = 0.04). Normal sensory status at a distance was significantly associated with TEC (p <  0.01). Multivariate analysis using multiple logistic regression analysis showed that normal sensory status was significantly associated with TEC (p = 0.02). Conclusions The test using a near-infrared camera vision monitor system was a simple and objective tool in identifying TEC evoked by bright light. The presence of TEC strongly correlated with self-reporting photosensitivity in patients with IXT. However, TEC may be an independent phenomenon with motor alignment, stereopsis, and pupil reflex pathway in patients with IXT.This work was supported by the New Faculty Startup Fund from Seoul National University (JHJ)

Left dominance of EEG abnormalities in patients with transient global amnesia

AbstractPurposeTransient global amnesia (TGA) is a syndrome of unknown etiology. Electroencephalographic (EEG) abnormalities in TGA have been reported previously. We analyzed the frequency and characteristics of EEG abnormalities in patients with TGA.MethodsWe collected EEGs of patients with a clinical diagnosis of TGA who had visited the emergency room or the outpatient clinic over a period of 8 years and compared clinical and demographic characteristics of the patients with normal EEGs with those with abnormal EEGs.ResultsEEG abnormalities were found in 35 (22.9%) out of 153 patients and epileptiform discharges were seen in 26 (74.3%) out of these 35 patients. Spikes or sharp waves were detected on the left side only (48.6%) or on both sides (25.7%), but none of the patients showed spikes or sharp waves on right side only. In six patients the EEG had normalized within three months of presentation, in ten within six months, and in twelve by one year. The EEG remained abnormal in eleven out of the 23 patients one year after presentation.ConclusionIn this largest consecutive EEG study at one center, the proportion of patients with TGA in whom epileptiform discharges were demonstrated within days of the episode of TGA was significantly higher than in the previous literature. EEG abnormalities such as spikes or sharp waves spontaneously disappeared in almost half of cases over one-year of follow-up. There was a clear left dominance of EEG abnormalities in patients with TGA

The effects of curcumin on the fibrous envelope surrounding silicone implants in rats

Background Capsular contracture is the most common serious breast surgery complication. The cause of capsular formation remains unknown, but chronic inflammation is commonly considered to cause excessive fibrosis. Curcumin has anti-inflammatory effects and thus can relieve the symptoms of inflammatory diseases, as demonstrated in animal studies. This study aimed to evaluate the effects of curcumin on the fibrous envelope covering silicone implants in a rat model. Methods Two solid 1.8-cm oval-shaped silicone implants were placed beneath both sides of the back in 20 Sprague-Dawley rats. The control group included 10 rats that were fed a normal diet (group A), while the experimental group (group B) included the remaining 10 rats that were fed ground curcumin. En bloc excision was conducted at 8 postoperative weeks. Capsular thickness and inflammatory cell distribution were examined using a fixed tissue sample. Results Gross findings and histologic differences between the groups were observed. The experimental group had a significantly lower mean total capsular thickness than the control group (177.4±31.4 μm vs. 145.9±32.5 μm, P=0.007). A significant decreasing tendency was found in several inflammatory cells in the experimental group (7,070±744.3/mm2 vs. 2,640±301.7/mm2, P=0.001). Conclusions Curcumin significantly reduced the inflammatory reaction, and will help to lower the risk of capsular contracture. Long-term studies are required to determine whether this hypothesis can provide a basis for a viable therapeutic strategy to reduce capsular contracture

Normal Gallbladder Visualization during Post-Ablative Iodine-131 Scan of Thyroid Cancer

Whole body iodine-131 scan is a well-established imaging method for the detection of metastatic or residual tumor sites in patients with well-differentiated thyroid cancer. Many false-positive iodine-131 scan findings mimicking metastatic thyroid cancer have long been reported. The authors describe a false positive uptake in normal gallbladder on post-ablative iodine-131 scan in a patient with papillary thyroid cancer. This finding should be considered to be another possible false-positive finding on iodine-131 whole body scan