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Lee J, Lee KJ, Yoo SK. Development of a new signal processing algorithm based on independent component analysis for single channel ECG data. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2007; 2006:224-6. [PMID: 17271650 DOI: 10.1109/iembs.2004.1403132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
In this paper, we proposed a new signal processing algorithm based on independent component analysis (ICA) for single channel ECG data. For the application ICA to single channel data, mixed (multi-channel) signals are constructed by adding some delay to original data. By ICA, signal enhancement is acquired. For validation of usefulness of this signal, QRS complex detection was accompanied. In QRS detection process, Hilbert transform and wavelet transform were used and good QRS detection efficacy was obtained. Furthermore, a signal, which could not be filtered properly using existing algorithm, also had better signal enhancement. In future, we need to study on the algorithm optimization and simplification.
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Lee KJ, Jang KS, Shon YM. Chronic deep brain stimulation of subthalamic and anterior thalamic nuclei for controlling refractory partial epilepsy. ACTA NEUROCHIRURGICA. SUPPLEMENT 2007; 99:87-91. [PMID: 17370771 DOI: 10.1007/978-3-211-35205-2_17] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
OBJECTIVES Experimental data and case reports of intractable epilepsy patients treated with deep brain stimulation (DBS) of the internal nuclei suggest a considerable anticonvulsant effect. We intended to describe the results of DBS on subthalamic nuclei and anterior thalamic nuclei (STN and ATN) from our patients and to evaluate the long-term efficiency and safety of DBS for controlling intractable epilepsy. METHODS Six patients with refractory epilepsy and inadequate for surgery were implanted with DBS electrodes (3 in STN and 3 in ATN, respectively), switched on after a week of insertion followed by chronological observation. Seizure counts were monitored and compared with pre-implantation baseline. RESULTS There was significant clinical improvement in respect of reduction of seizure frequency as well as the alleviation of ictal severity in almost patients. The mean reduction in seizure frequency was 62.3% (49.1% from STN vs. 75.4% from ATN). Except one patient (patient 3) with accidental infection on the right anterior chest, no complication or withdrawal of DBS was seen during our study. CONCLUSION DBS on STN and ATN demonstrated their clear efficiency and relative safety comparable or superior to previous studies during long term follow-up. Subsequent, well designed studies warrant the further increase of the knowledge about antiepileptic effect of DBS.
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Rogers PL, Jeon YJ, Lee KJ, Lawford HG. Zymomonas mobilis for fuel ethanol and higher value products. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2007; 108:263-88. [PMID: 17522816 DOI: 10.1007/10_2007_060] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
High oil prices, increasing focus on renewable carbohydrate-based feedstocks for fuels and chemicals, and the recent publication of its genome sequence, have provided continuing stimulus for studies on Zymomonas mobilis. However, despite its apparent advantages of higher yields and faster specific rates when compared to yeasts, no commercial scale fermentations currently exist which use Z. mobilis for the manufacture of fuel ethanol. This may change with the recent announcement of a Dupont/Broin partnership to develop a process for conversion of lignocellulosic residues, such as corn stover, to fuel ethanol using recombinant strains of Z. mobilis. The research leading to the construction of these strains, and their fermentation characteristics, are described in the present review. The review also addresses opportunities offered by Z. mobilis for higher value products through its metabolic engineering and use of specific high activity enzymes.
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Lee KJ, Paley MNJ, Wild JM. Combined simulated annealing and Shinnar-Le Roux pulse design of slice-multiplexed RF pulses for multi-slice imaging. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2006; 182:133-42. [PMID: 16828567 DOI: 10.1016/j.jmr.2006.06.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2006] [Revised: 06/16/2006] [Accepted: 06/16/2006] [Indexed: 05/10/2023]
Abstract
Slice-multiplexed RF pulses have recently been introduced for simultaneous multi-slice imaging. Their novel aspect is that each slice is given a different linear phase profile, and hence a different slice-rephasing requirement, by the pulse. During readout, extra slice gradients are applied such that when one slice is rephased, the others are dephased to prevent aliasing. In this paper, an improved method of designing slice-multiplexed RF pulses is presented: component pulses which are optimized with simulated annealing for a specific rephasing are combined using Shinnar-Le Roux methods. In this way, non-linearities at higher flip angles are taken into account and more slices can be excited. Bloch simulations show the phase and amplitude profile of component pulses are faithfully preserved in the multiplexed pulse. Three- and four-slice multiplex pulses are demonstrated in gradient- and spin-echo in-vivo imaging.
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Nagaraja S, Lee KJ, Coley SC, Capener D, Walton L, Kemeny AA, Wilkinson ID, Griffiths PD. Stereotactic radiosurgery for brain arteriovenous malformations: quantitative MR assessment of nidal response at 1 year and angiographic factors predicting early obliteration. Neuroradiology 2006; 48:821-9. [PMID: 16944119 DOI: 10.1007/s00234-006-0131-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2005] [Accepted: 06/27/2006] [Indexed: 10/24/2022]
Abstract
INTRODUCTION We investigated the role of magnetic resonance angiography (MRA) in the early follow-up of patients after stereotactic radiosurgery (STRS) for cerebral arteriovenous malformations (AVMs) and determined the influence of individual morphological factors of AVMs in early response to treatment. METHODS A group of 40 patients (41 AVMs) consented to a dedicated 1.5-T MR protocol 12 months after receiving STRS for a brain AVM. In addition to standard spin echo sequences, 3-D contrast-enhanced sliding interleaved Ky MRA (CE-SLINKY) and dynamic time-resolved subtraction angiography (MR-DSA) were performed. Nidal volumes were calculated using CE-SLINKY data in patients with a persisting arteriovenous shunt. Planning angiographic data was investigated in all 40 patients. The following AVM factors were used in the statistical analysis to determine their role in nidus obliteration: (1) maximum linear dimension, (2) nidal volume, (3) AVM location (4) nidal morphology, (5) venous drainage, (6) "high-flow angiographic change", (7) prior embolization, and (8) dose reduction. RESULTS Complete nidal obliteration was found in 9 patients, 26 showed greater than 50% nidal reduction and 6 had less than 50%. Two AVM factors, venous drainage and AVM location, were found to significantly correlate with rate of obliteration. CONCLUSION We successfully demonstrated the use of MRA to quantitatively assess the response of AVMs to STRS. Two AVM factors, venous drainage and AVM location were found to correlate with rate of obliteration prior to the application of the Bonferroni correction, but if this more rigorous statistical test was applied then none of the factors was found to be significant.
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Lee KJ. Pay for performance (P4P). BULLETIN OF THE AMERICAN COLLEGE OF SURGEONS 2006; 91:62. [PMID: 18557210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
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Lee KJ, Kim JH, Cho SW. Gabapentin reduces rectal mechanosensitivity and increases rectal compliance in patients with diarrhoea-predominant irritable bowel syndrome. Aliment Pharmacol Ther 2005; 22:981-8. [PMID: 16268973 DOI: 10.1111/j.1365-2036.2005.02685.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Gabapentin has been shown to reduce elements of central sensitization in human experimental hyperalgesia. It remains uninvestigated whether gabapentin has beneficial effects for irritable bowel syndrome associated with visceral hypersensitivity. AIMS To evaluate the effects of gabapentin on sensory and motor function of the rectum in patients with diarrhoea-predominant irritable bowel syndrome. METHODS Forty patients with diarrhoea-predominant irritable bowel syndrome completed this randomized, double-blind, placebo-controlled, parallel-grouped study. All patients received a barostat study and were subsequently randomized for 5-day treatment with gabapentin 300 mg/day and then 600 mg/day or placebo. On day 6, after subjects had their morning dose, the barostat experiment was repeated. RESULTS The threshold pressures for bloating, discomfort and pain significantly increased after gabapentin, but not after placebo. Significant increase in the pressure and corresponding wall tension inducing discomfort or pain were observed in the gabapentin group, but not in the placebo group. Rectal compliance significantly increased after gabapentin, but not after placebo. The postprandial increase of rectal tone was not affected by gabapentin. CONCLUSION Our results show that gabapentin reduces rectal sensory thresholds through attenuating rectal sensitivity to distension and enhancing rectal compliance in diarrhoea-predominant irritable bowel syndrome patients. The clinical efficacy of this drug in irritable bowel syndrome patients warrants investigation.
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Lee YR, Choi YW, Lee KJ, Jeon SC, Park CK, Heo JN. CT halo sign: the spectrum of pulmonary diseases. Br J Radiol 2005; 78:862-5. [PMID: 16110114 DOI: 10.1259/bjr/77712845] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The CT halo sign indicates ground glass attenuation surrounding a pulmonary nodule on CT. Although it was initially proposed as an early, specific finding of invasive pulmonary aspergillosis, it can be caused by many other pathological conditions such as infection, neoplastic and inflammatory diseases. The halo of ground glass attenuation pathologically represents pulmonary haemorrhage, tumour infiltration, or non-haemorrhagic inflammatory processes. Although non-specific, this sign is important because the clinical setting and associated radiological features may give a clue to the differential diagnosis. In this review, we demonstrate the spectrum of pulmonary diseases showing the "CT halo sign" on thin-section CT and discuss their radiological and clinical features.
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Lee KJ, Paley MNJ, Griffiths PD, Wild JM. Method of generalized projections algorithm for image-based reduction of artifacts in radial imaging. Magn Reson Med 2005; 54:246-50. [PMID: 15968656 DOI: 10.1002/mrm.20554] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This work describes the method of generalized projections (MGP) as an image-based, postprocessing method to correct for phase inconsistencies caused by echo misalignments in radial imaging. Computer simulations show that MGP can correct for echo shifts, constant phase, and amplitude errors, but the accuracy of the correction is limited, and this accuracy is reduced by the addition of more degrees of freedom. In phantom experiments, MGP performed better than magnitude filtered backprojection and anti-parallel projections correction.
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Abstract
Functional dyspepsia is a highly prevalent symptom complex and a heterogenous disorder. Recent studies showed potential associations between specific pathophysiologic disturbances and dyspeptic symptoms. Delayed gastric emptying reported in about 30% of patients with functional dyspepsia is associated with the symptoms of postprandial fullness, nausea, and vomiting. Impaired gastric accommodation present in 40% of functional dyspepsia patients is found to be associated with early satiety. Hypersensitivity to gastric distension is observed in 37% of functional dyspepsia patients and associated with the symptoms of postprandial pain, belching, and weight loss. Psychosocial factors and altered response to duodenal lipids or acid have also been identified as pathophysiologic mechanisms. Therapeutic options are still limited but targeted therapy directed at the underlying pathophysiology seems desirable. Thus, efforts to further elucidate underlying pathophysiologic mechanisms and identify the appropriate patient population using some type of pathophysiologic testing will be required.
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Veldtman GR, Norgard G, Wåhlander H, Garty Y, Thabit O, McCrindle BW, Lee KJ, Benson LN. Creation and enlargement of atrial defects in congenital heart disease. Pediatr Cardiol 2005; 26:162-8. [PMID: 15868326 DOI: 10.1007/s00246-004-0953-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Transcatheter creation and enlargement of interatrial defects (IAD) may improve hemodynamics; however, procedural outcomes have not been well defined. Hospital records were reviewed for children who underwent percutaneous procedures to create and enlarge an IAD and were grouped as follows: (1) right and (2) left heart obstructive lesions, (3) left atrial (LA) decompression during left heart assist, (4) failing Fontan circulation, and (5) miscellaneous. Forty-five children (mean age, 3.4 +/- 4.7 years; 30 (67%) male) were identified. In group 1 (n = 6), all achieved endpoints of right atrial (RA) decompression (n = 2), improved left ventricular filling (n = 3), or improved arterial saturations (n = 1). In group 2 (n = 18), mean LA pressure decreased (21 +/- 6 to 13 +/- 5 mmHg, p < 0.001) and arterial saturations increased (61 +/- 13% to 78 +/- 11%, p < 0.001). All except 2 patients achieved definitive repair, further palliation (n = 9), or heart transplantation (HTX) (n = 7). In group 3 (n = 5), the LA was decompressed (21 to 13 mmHg, p = 0.03) in all, and all except 1 patient survived to HTX (n = 2) or full recovery (n = 2). In group 4 (n = 11), of 7 patients with a low cardiac output syndrome after surgery, despite improved atrial shunting, 3 died and 1 required a HTX. In group 5 (n = 5), RA decompression (n = 1) or improved arterial saturation (n = 4) was achieved in all. Overall, 5-year HTX free survival was 75%. Mechanical ventilation before the procedure (p < 0.001), the need for a blade septostomy (p = 0.002), and higher LA pressures after the procedure (p = 0.04) independently predicted mortality or the requirement for HTX. Transcatheter optimization of an atrial communication can help optimize treatment strategies and has a low procedural risk.
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Jung YS, Lee KJ, Yoon TI, Kim MW, Yim HE, Kim YB, Park HB, Hong J. Juvenile fibroadenoma in 13-month-old female child. J Paediatr Child Health 2005; 41:78-9. [PMID: 15670233 DOI: 10.1111/j.1440-1754.2005.00545.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Lee KJ, Wild JM, Griffiths PD, Paley MNJ. Simultaneous multislice imaging with slice-multiplexed RF pulses. Magn Reson Med 2005; 54:755-60. [PMID: 16155891 DOI: 10.1002/mrm.20643] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A method for simultaneous multislice imaging is presented that uses a multislice RF pulse that imparts a different linear phase profile to each slice. During readout, slices are unaliased by using extra slice-select gradient lobes, which rephase and dephase individual slices one at a time. Compared to other simultaneous slice methods, this method avoids distortion by slice-select gradients, and does not require extra views or additional hardware. However, because one echo per slice is required, the method requires a longer read period. This can cause non-ideal rephasing of the individual slices due to susceptibility gradients, which manifests itself as crosstalk between slices. There is also a concomitant increase in the minimum TR of the sequence. The method is demonstrated with phantom and in vivo images using gradient-echo and spin-echo versions.
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Vera VE, Gutierrez JA, Lee KJ, Tardy ME, Dibildox JJ. International Symposia: Rhinoplasty for Latin Noses. Otolaryngol Head Neck Surg 2004. [DOI: 10.1016/j.otohns.2004.06.222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Lee KJ, Papadakis NG, Barber DC, Wilkinson ID, Griffiths PD, Paley MNJ. A method of generalized projections (MGP) ghost correction algorithm for interleaved EPI. IEEE TRANSACTIONS ON MEDICAL IMAGING 2004; 23:839-848. [PMID: 15250636 DOI: 10.1109/tmi.2004.827970] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Investigations into the method of generalized projections (MGP) as a ghost correction method for interleaved EPI are described. The technique is image-based and does not require additional reference scans. The algorithm was found to be more effective if a priori knowledge was incorporated to reduce the degrees of freedom, by modeling the ghosting as arising from a small number of phase offsets. In simulations with phase variation between consecutive shots for n-interleaved echo planar imaging (EPI), ghost reduction was achieved for n = 2 only. With no phase variation between shots, ghost reduction was obtained with n up to 16. Incorporating a relaxation parameter was found to improve convergence. Dependence of convergence on the region of support was also investigated. A fully automatic version of the method was developed, using results from the simulations. When tested on in vivo 2-, 16-, and 32-interleaved spin-echo EPI data, the method achieved deghosting and image restoration close to that obtained by both reference scan and odd/even filter correction, although some residual artifacts remained.
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Garcia-Abiado MA, Mbahinzireki G, Rinchard J, Lee KJ, Dabrowski K. Effect of diets containing gossypol on blood parameters and spleen structure in tilapia, Oreochromis sp., reared in a recirculating system. JOURNAL OF FISH DISEASES 2004; 27:359-368. [PMID: 15189376 DOI: 10.1111/j.1365-2761.2004.00551.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The high cost of fish meal in tilapia diets warrants the potential use of cottonseed meal (CSM) as an alternative source of high quality protein. The effects of varying levels of CSM (0, 25, 50, 75 and 100%) as fish meal protein replacement on growth, blood parameters, spleen characteristics, free and bound gossypol in blood plasma, haemoglobin and haematocrit were determined in tilapia. Gossypol (C(30)H(30)O(8)) is a polyphenolic substance found in cottonseed that has known toxic effects in fish. Tilapias (n = 219, average weight = 11.3 +/- 3.9 g) were randomly distributed into 15, 32-L glass aquaria, representing five dietary treatments and three replicates per treatment. Each aquarium containing 13-16 fish was supplied with thermoregulated, recirculating water (27 +/- 1 degrees C) at 1 L min(-1) flow rate and photoperiod was constant (12 h L/12 h D). Fish fed 25-50% CSM protein replacement showed similar body weights and total lengths as the controls at the completion of the 16-week trial. Fish fed 75 and 100% CSM protein replacement showed a significant decline in body weight and total length. Fish fed 25-100% CSM protein replacement had significantly lower haematocrit and haemoglobin (ANOVA/LSD, P < 0.05) compared with levels in controls. The decline was most prominent in groups fed diets with 50-100% CSM protein replacement. Total and free gossypol concentrations of blood plasma significantly increased with increasing levels of CSM replacement (P < 0.05). No gossypol was found in blood plasma of fish from the control group. The occurrence of immature and abnormal erythrocytes was significantly greater among fish fed 75 and 100% CSM diets compared with fish fed 0-50% CSM diets. Spleen-somatic index (spleen weight/body weight x 100) did not differ between control fish and fish fed 50-100% CSM diets. Spleen abnormalities, such as large depositions of haemosiderin and melanin pigments and proliferation of melano-macrophage centres, lymphocytic depletion of the white pulp areas (hypocellularity), and presence of vacuoles and necrotic areas were observed among fish fed 50-100% CSM protein diets. In general, the pathological effects of gossypol in tilapia (low haemoglobin and haematocrit levels, abundance of immature red blood cells or polychromatocytes, abnormal spleen morphology) were similar to the effects of vitamin E and/or vitamin C deficiencies observed in other studies.
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Lee KJ, Paley MN, Wilkinson ID, Griffiths PD. Magnetic resonance imaging with stepped B(0) fields. Magn Reson Imaging 2003; 21:625-9. [PMID: 12915193 DOI: 10.1016/s0730-725x(03)00085-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
This paper introduces the concept of imaging with stepped magnetic fields within the main B(0) field. The resonance frequency within each step is separated from the next by an amount greater than the imaging bandwidth. Each step thus gives rise to a separate imaging region enabling simultaneous imaging over multiple slices without aliasing. The auxiliary magnetic field regions are produced by coil inserts. The principle is illustrated using simple coil designs which introduce up to two steps into the main B(0) field. Phantoms placed in each uniform region were successfully imaged simultaneously with no aliasing.
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Song MS, Kong ES, Kim GB, Kim NC, Kim CH, Kim CK, Kim HK, Roh YJ, Shin KR, Ahn SY, Lee KJ, Lee YW, Chang SO, Chon SJ, Cho NO, Cho MO, Choi KS. Development of Gerontological Nursing Curriculum Model. J Korean Acad Nurs 2003; 33:376-85. [PMID: 15314436 DOI: 10.4040/jkan.2003.33.3.376] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
PURPOSE This study was conducted to develop gerontological curriculum model which reflects the need of Korean society. METHOD Three round Delphi survey method was applied to find consensus of gerontological nursing competencies (knowledge, attitudes and skills) for graduates of nursing schools from the panel of gerontological nursing practice experts. Important concepts in gerontological nursing were delineated from literature review and discussions of gerontological nursing educators. Based on these results the gerontological nursing curriculum model was developed and course structure outlined by the researchers as a group. RESULT As the result of delphi survey, 32 items of knowledge, 29 items of attitude, and 21 items of skill were identified. The curriculum model constructed around a cube with three plane- functional capacity levels, settings, and nursing practice. Specific knowledge, attitudes and skills for gerontological theory and practicum course were suggested. Competency items were assigned to theory and/or practice. CONCLUSION A curriculum model for gerontological nursing has been developed by a group of gerontological nursing educators. The curriculum model should be further tested and developed with detailed theory and practicum course outline and textbooks.
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Lee KJ, Barber DC, Paley MN, Wilkinson ID, Papadakis NG, Griffiths PD. Image-based EPI ghost correction using an algorithm based on projection onto convex sets (POCS). Magn Reson Med 2002; 47:812-7. [PMID: 11948745 DOI: 10.1002/mrm.10101] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
This work describes the use of a method, based on the projection onto convex sets (POCS) algorithm, for reduction of the N/2 ghost in echo-planar imaging (EPI). In this method, ghosts outside the parent image are set to zero and a model k-space is obtained from the Fourier transform (FT) of the resulting image. The zeroth- and first-order phase corrections for each line of the original k-space are estimated by comparison with the corresponding line in the model k-space. To overcome problems of phase wrapping, the first-order phase corrections for the lines of the original k-space are estimated by registration with the corresponding lines in the model k-space. It is shown that applying these corrections will result in a reduction of the ghost, and that iterating the process will result in a convergence towards an image in which the ghost is minimized. The method is tested on spin-echo EPI data. The results show that the method is robust and remarkably effective, reducing the N/2 ghost to a level nearly comparable to that achieved with reference scans.
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Song JH, Lee KJ, Lee SW, Kim MJ. Incisional hernia after corrective omentectomy for peritoneal dialysis catheter malposition. ADVANCES IN PERITONEAL DIALYSIS. CONFERENCE ON PERITONEAL DIALYSIS 2002; 17:132-7. [PMID: 11510261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
Laparotomic correction with or without omentectomy is occasionally required for malposition of a peritoneal dialysis (PD) catheter. We reviewed the incidence of incisional hernia following laparotomic PD catheter correction with or with omentectomy. From January 1996 to December 1998, PD catheters were implanted by non open-dissection technique using a trocar in 148 patients. Laparotomy for PD catheter malposition was required in 20 of the 148 patients. Omentectomy was performed simultaneously in 11 patients. After laparotomy, the wound was closed with interrupted or continuous layered polyglycolidelactide polymer sutures. Dialysis was resumed after the third or fourth day. Incisional hernia developed in 30% (6/20) of all patients undergoing laparotomy, but in none of the patients not undergoing laparotomy. The incidence increased when omentectomy was performed [5/11 (45.5%) vs 1/9 (11.1%)]. Multiparity, female sex, and laparotomy at a later time also predisposed to development of incisional hernia. Among the patients with incisional hernia, 2 patients showed multiple recurrences and 1 patient showed later leakage; PD catheters were lost in these patients. Another 3 patients continued continuous ambulatory peritoneal dialysis (CAPD) without a recurrence. The results suggest that incisional hernia is prevalent following laparotomic PD catheter correction, especially when omentectomy is performed simultaneously. Situations that seem to increase the risk of incisional hernia--inevitably encountered during corrective laparotomic omentectomy--are discussed. An evaluation is necessary concerning whether omentectomy acts as an independent risk factor for incisional hernia, and whether incisional hernia occurs more frequently when omentectomy is performed after a period on CAPD as compared with when it is performed at the time of PD catheter implantation. Laparotomic omentectomy should be performed as a last resort for the correction of PD catheter malposition.
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Shin KR, Kong ES, Kim GB, Kim NC, Kim CH, Kim CK, Kim HK, Ro YJ, Song MS, Ahn SY, Lee KJ, Lee YW, Chang SO, Chon SJ, Cho NO, Cho MO, Choi KS. Lived Experience with Aging in Middle-Aged Woman. J Korean Acad Nurs 2002. [DOI: 10.4040/jkan.2002.32.6.878] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Lee KJ, Paley MN, Wilkinson ID, Griffiths PD. Fast two-dimensional MR imaging by multiple acquisition with micro B(0) array (MAMBA). Magn Reson Imaging 2002; 20:119-25. [PMID: 11973037 DOI: 10.1016/s0730-725x(02)00488-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
A new method for acquiring MR data in two dimensions is described. This is achieved by combining coils into an array so as to produce a unique local magnetic field within each coil when placed within the B(0) field of a standard MRI scanner. In this way each known location of a coil is associated with a unique resonant frequency. Each coil now represents a location of a pixel in the plane, and after Fourier transformation of the signal the resulting frequency spectrum gives immediately the spin distribution in the plane of the array. In effect, the two-dimensional spatial distribution is frequency encoded without the use of switched gradients or phase encoding. As only static fields are used, this technique offers the potential of fast imaging. Furthermore, signals from different locations would also be inherently time-registered. Initial experiments to demonstrate the principle are described, using a square array of 5 by 5 coils. The currents in the coils were determined by using a genetic algorithm. Echoes from pellet phantoms placed in the array were acquired using standard spin-echo sequences with gradients switched off. The results are promising, with the spectra showing generally good resolution between peaks, enabling localisation in up to half the pixels. Technical difficulties are discussed and possible applications are outlined.
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Lee KJ, You HJ, Park SJ, Kim YS, Chung YC, Jeong TC, Jeong HG. Hepatoprotective effects of Platycodon grandiflorum on acetaminophen-induced liver damage in mice. Cancer Lett 2001; 174:73-81. [PMID: 11675154 DOI: 10.1016/s0304-3835(01)00678-4] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The protective effects of an aqueous extract from the roots of Platycodon grandiflorum A. DC (Campanulaceae), Changkil (CK), on acetaminophen (APAP)-induced hepatotoxicities and the possible protective mechanisms involved were investigated in mice. Pretreatment with CK prior to the administration of APAP significantly prevented the increase in serum alanine aminotransferase and aspartate aminotransferase activity and hepatic lipid peroxidation in a dose-dependent manner. APAP-induced hepatotoxicity was also essentially prevented as evidenced by liver histopathology. Hepatic glutathione levels and glutathione-S-transferase activities were not affected by treatment with CK alone, but pretreatment with CK protected the APAP-induced depletion of hepatic glutathione levels. The effects of CK on cytochrome P450 (P450) 1A2 and 2E1, the major isozymes involved in APAP bioactivation, were investigated. In microsomal incubations, CK effectively inhibited P450 lA2-dependent methoxyresorufin O-deethylase activities and the P450 2E1-dependent p-nitrophenol and aniline hydroxylase. The results suggest that the protective effects of CK against the APAP-induced hepatotoxicity may, at least in part, be due to its ability to block P450-mediated APAP bioactivation.
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Cho SJ, Lee NS, Jung YS, Lee H, Lee KJ, Kim E, Chae SK. Identification of structural domains affecting transactivation potential of Nm23. Biochem Biophys Res Commun 2001; 289:738-43. [PMID: 11726210 DOI: 10.1006/bbrc.2001.6042] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The strong transactivation activity of the C-terminal half (amino acids 76-152) of Nm23 was reported previously. Here we examined a structural domain preventing or necessary to its transactivation activity. The C-terminal 1/4 (amino acids 109-152) was sufficient for transactivation, but the C-terminal half with a longer N-terminal extension (amino acids 58-152) caused the loss of the transactivation ability. Furthermore, coexpression of the N-terminal half with the C-terminus of Nm23-H1 blocked the transactivation activity of the C-terminal half, where direct interaction of both truncated proteins was demonstrated in vitro. Transactivation activities in the C-terminal halves of the known mutants (P96S, H118F, S120G, and S120A) exhibiting differential antimetastasis effects were also tested. Significant reduction of transactivation activity was observed only in H118F, indicating that NPD kinase active-site histidine is required. This suggests that transactivation potential of Nm23 is related to NDP kinase activity but not to metastasis suppressor activity.
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