1,504 research outputs found
An Analysis of Research Trends in Brain-based Learning in Adult Education and HRD Fields: The Content Analysis and Network Text Analysis
The purpose of this study is to address the trends of the research on brain-based learning and to present an integrative theoretical framework to provide new insights and future directions in adult education and HRD fields. Based on the neuroscientific perspective, the implications of which the ways to conceptually broaden educational research and practice were discussed
COMBUSTION CHARACTERISTICS AND EMISSION OF HAZARDOUS AIR POLLUTANTS IN COMMERCIAL FLUIDIZED BED COMBUSTORS FOR SEWAGE SLUDGE
Since the disposal of sewage sludge in ocean has been prohibited recently according to London Dumping Convention, technological need for treating sewage sludge safely and efficiently are getting increased in Korea. FBC (Fluidized Bed Combustor) technology has been selected and utilized as one of the alternatives because of combustible content in sludge, on-going process development to maintain the best combustion efficiency, and good heat recovery for energy utilization. In this paper, the process and combustion characteristics of commercially operating FBC incineration plants with the capacity ranging from 50 – 150 tons of sludge per day were investigated by comparing emission data from 4 different plants. Concentrations of hazardous gaseous pollutants (HAPs) such as fine particulate matter, heavy metals, and dioxin from sludge combustion before and after air pollution control devices were measured and analyzed at commercial operating conditions of one typical incinerator. Most of emission data at stack showed under the environmental regulatory limits. Mercury and some heavy metals emission have been reduced significantly as co-beneficial effect since the air pollution control configuration was well arranged and installed to control the regulatory gases such as NOx, SO2, particulates, and dioxin. Sludge, especially generated from industrial plants, contained measurable amounts of acidic materials and heavy metals including Hg. Therefore, such metal emission should receive an attention by monitoring them and further mass balance study for better understanding their fates in the process must proceed in future
Evaluation of the usefulness of three-dimensional optical coherence tomography in a guinea pig model of endolymphatic hydrops induced by surgical obliteration of the endolymphatic duct
Optical coherence tomography (OCT) has advanced significantly over the past two decades and is currently used extensively to monitor the internal structures of organs, particularly in ophthalmology and dermatology. We used ethylenediamine tetra-acetic acid (EDTA) to decalcify the bony walls of the cochlea and investigated the inner structures by deep penetration of light into the cochlear tissue using OCT on a guinea pig model of endolymphatic hydrops (EH), induced by surgical obliteration of the endolymphatic duct. The structural and functional changes associated with EH were identified using OCT and auditory brainstem response tests, respectively. We also evaluated structural alterations in the cochlea using three-dimensional reconstruction of the OCT images, which clearly showed physical changes in the cochlear structures. Furthermore, we found significant anatomical variations in the EH model and conducted graphical analysis by strial atrophy for comparison. The physical changes included damage to and flattening of the organ of Corti-evidence of Reissner's membrane distention-and thinning of the lateral wall. These results indicate that observation of EDTA-decalcified cochlea using OCT is significant in examination of gradual changes in the cochlear structures that are otherwise not depicted by hematoxylin and eosin staining © The Authorsopen0
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
A Novel Meatoplasty Method in Canal Wall Down Tympanomastoidectomy: A Perichondrial Posterior Fixation Technique
ObjectivesAlthough it is well recognized that a small meatus after canal wall down (CWD) tympanomastoidectomy can cause a lifetime problem, unsatisfactory results are frequently encountered. We herein introduce a novel technique, perichondrial posterior fixation (PPF), to maintain a wide external auditory canal (EAC), to minimize postoperative wound infection due to the smaller dead space and to improve the posterior auricular cosmetic outcome.MethodsA total of 73 patients who underwent CWD tympanomastoidectomy were included. Interventions are CWD tympanomastoidectomy with the PPF technique. Review of the medical records and evaluation of the postoperative size of the meatus and the extent of the cavum conchal cartilage buried within the mastoid cavity by taking digital photographs.ResultsThirty males and 43 females were included and the mean age was 44.1 yr (range, 6 to 66 yr). The mean follow-up duration was 26 months (range, 12 to 56 months). All ears maintained a clean and large external meatus. The posterior auricular cavum conchal cartilage was successfully prevented from being buried into the mastoid cavity in all ears. The extent of cartilage buried into the mastoid cavity was much reduced compared to the conventional technique.ConclusionThe PPF technique, which is a novel meatoplasty technique in CWD tympanomastoidectomy, seems to be effective in maintaining a large external meatus and improving the cosmetic outcome with minimal risk of complications
The cortical activation pattern by a rehabilitation robotic hand: a functional NIRS study
Introduction: Clarification of the relationship between external stimuli and brain response has been an important topic in neuroscience and brain rehabilitation. In the current study, using functional near infrared spectroscopy (fNIRS), we attempted to investigate cortical activation patterns generated during execution of a rehabilitation robotic hand. Methods: Ten normal subjects were recruited for this study. Passive movements of the right fingers were performed using a rehabilitation robotic hand at a frequency of 0.5 Hz. We measured values of oxy-hemoglobin (HbO), deoxy-hemoglobin (HbR) and total-hemoglobin (HbT) in five regions of interest: the primary sensory-motor cortex (SM1), hand somatotopy of the contralateral SM1, supplementary motor area (SMA), premotor cortex (PMC), and prefrontal cortex (PFC). Results: HbO and HbT values indicated significant activation in the left SM1, left SMA, left PMC, and left PFC during execution of the rehabilitation robotic hand (uncorrected, p < 0.01). By contrast, HbR value indicated significant activation only in the hand somatotopic area of the left SM1 (uncorrected, p < 0.01). Conclusions: Our results appear to indicate that execution of the rehabilitation robotic hand could induce cortical activation. © 2014 Chang, Lee, Gu, Lee, Jin, Yeo, Seo and Jang.1
Retinoid production using metabolically engineered Escherichia coli with a two-phase culture system
<p>Abstract</p> <p>Background</p> <p>Retinoids are lipophilic isoprenoids composed of a cyclic group and a linear chain with a hydrophilic end group. These compounds include retinol, retinal, retinoic acid, retinyl esters, and various derivatives of these structures. Retinoids are used as cosmetic agents and effective pharmaceuticals for skin diseases. Retinal, an immediate precursor of retinoids, is derived by β-carotene 15,15'-mono(di)oxygenase (BCM(D)O) from β-carotene, which is synthesized from the isoprenoid building blocks isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP). Retinoids are chemically unstable and biologically degraded via retinoic acid. Although extensive studies have been performed on the microbial production of carotenoids, retinoid production using microbial metabolic engineering has not been reported. Here, we report retinoid production using engineered <it>Escherichia coli </it>that express exogenous BCM(D)O and the mevalonate (MVA) pathway for the building blocks synthesis in combination with a two-phase culture system using a dodecane overlay.</p> <p>Results</p> <p>Among the BCM(D)O tested in <it>E. coli</it>, the synthetic retinoid synthesis protein (SR), based on bacteriorhodopsin-related protein-like homolog (Blh) of the uncultured marine bacteria 66A03, showed the highest β-carotene cleavage activity with no residual intracellular β-carotene. By introducing the exogenous MVA pathway, 8.7 mg/L of retinal was produced, which is 4-fold higher production than that of augmenting the MEP pathway (<it>dxs </it>overexpression). There was a large gap between retinal production and β-carotene consumption using the exogenous MVA pathway; therefore, the retinal derivatives were analyzed. The derivatives, except for retinoic acid, that formed were identified, and the levels of retinal, retinol, and retinyl acetate were measured. Amounts as high as 95 mg/L retinoids were obtained from engineered <it>E. coli </it>DH5α harboring the synthetic <it>SR </it>gene and the exogenous MVA pathway in addition to <it>dxs </it>overexpression, which were cultured at 29°C for 72 hours with 2YT medium containing 2.0% (w/v) glycerol as the main carbon source. However, a significant level of intracellular degradation of the retinoids was also observed in the culture. To prevent degradation of the intracellular retinoids through <it>in situ </it>extraction from the cells, a two-phase culture system with dodecane was used. The highest level of retinoid production (136 mg/L) was obtained after 72 hours with 5 mL of dodecane overlaid on a 5 mL culture.</p> <p>Conclusions</p> <p>In this study, we successfully produced 136 mg/L retinoids, which were composed of 67 mg/L retinal, 54 mg/L retinol, and 15 mg/L retinyl acetate, using a two-phase culture system with dodecane, which produced 68-fold more retinoids than the initial level of production (2.2 mg/L). Our results demonstrate the potential use of <it>E. coli </it>as a promising microbial cell factory for retinoid production.</p
Analysis of P1 Latency in Normal Hearing and Profound Sensorineural Hearing Loss
ObjectivesP1 is a robust positivity at a latency of 50-150 msec in the auditory evoked potential of young children. It has been reported that over the first 2-3 years of life, there is a rapid decrease of the latency and the mean P1 latency in adults with normal hearing is approximately 60 msec. This study was designed to evaluate the change of the P1 latency in Koreans with normal hearing according to age and to compare this with the P1 latency of young patients with profound sensorineural hearing loss before and/or after cochlear implantation.MethodsAmong the patients who visited the Department of Otorhinolaryngology at Seoul National University Hospital from June 2007 to September 2009, the P1 response was recorded in 53 patients in the normal hearing group, in 13 patients in the pre-cochlear implantation (CI) group and in 10 patients in the post-CI group. A synthesized consonant-vowel syllable /ba/ was used to elicit the evoked responses. The evoked responses were collected using the center of the frontal head. For each subject, an individual grand average waveform was computed by averaging the ten recordings. The P1 latency was visually identified as a robust positivity in the waveform.ResultsFor the normal hearing group, the P1 latency showed the pattern of shortening as the age increased (coefficient, -0.758; P<0.001). For the pre-CI group, 10 cases showed delayed latencies and 3 cases did not show the P1 wave. For the post-CI group, the P1 latencies showed a less delayed tendency than those of the pre-CI group, but this was not statistically different.ConclusionThis report provides the standard value of the P1 latency at each age in Koreans for the first time and the findings support that the maturation of the central auditory pathways could be measured objectively using the P1 latency
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