• Applied Chemistry for Engineering
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• v.9 no.6
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• pp.822-828
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• 1998

Binary system of water and polyoxyethylene dodecyl ether, $C_{12}H_{25}(OCH_2CH_2)nOH$, have been studied by $^1H$ NMR techniques. For n=5($C_{12}EO_5$) and n=8($C_{12}EO_8$), the self-diffusion coefficients of nonionic surfactants in the isotropic phase($L_1$) have been measured by using pulsed field gradient technique for a range of temperature and concentrations. In addition the line widths of the different proton signals have been monitored, and samples of some liquid crystalline characteristic were also studied. Dramatic Broadening of the methylene signals of the alkyl($C_{12}H_{25}$) chain is observed as the hexagonal liquid crystalline phase is approached in the $C_{12}EO_5-$water system, while only small broadening is observed in the $C_{12}EO_8-$water system. It was shown that there was a growth of $C_{12}EO_5$ micelles to rods with increasing concentrations, while the $C_{12}EO_8-$ micelles at low temperature remain small in the concentration range. The self-diffusion coefficients of the surfactants decrease rapidly with increasing concentration until a minimum is reached after which there is slow increase. The location of the minimum point occurs at lower concentrations the temperature is close to the cloud point, where the system separate into two isotropic phase. In the line width studies, broadening is found at a certain temperature interval when the concentration is increased in the $C_{12}EO_5$ system. The results indicate that the surfactant aggregates grow in size at the cloud point is approached. The aggregates seem to be flexible and probably not to be of a definite shape close to the cloud point. In the $C_{12}EO_8$ system, the micelles are much less affected by an increase in temperature and micellar growth can't be unambiguously established. The methylene signals of the ethylene oxide moieties consistantly show narrower $^1H$ signals, showing that in the aggregates they are less ordered than the chain methylenes. The various changes in aggregate size and shape are correlated with the stability ranges of the isotropic and liquid crystalline phases according to phase diagrams from the literature. Both aggregate size and phase structure are in qualitative agreement with concentration based on the effective shape of the molecules at different temperature and concentration.

• Applied Chemistry for Engineering
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• v.10 no.6
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• pp.876-880
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• 1999

The surfactant self-diffusion coefficients of mixed micellar solutions of ionic and nonionic surfactants have been measured by the NMR pulsed field gradient spin echo(FT-PGSE) method. In addition, the line widths of $^1H$ NMR signal have been monitored. The system investgated are $C_{12}EO_5/SDS/D_2O$, $C_{12}EO_5/DTAC/D_2O$, and $C_{12}EO_8/SDS/D_2O$. In the sample series, the molar ratios of $D_2O$ to surfactant(ionic+nonionic) were kept constant while the surfactant mixing ratio was varied. For the $C_{12}EO_5$ system, the surfactant self-diffusion coefficient indicates minimum when the surfactant mixing ratio is about 20% ionic surfactant. The observed decrease in self-diffusion coefficients as nonionic surfactant was replaced by ionic surfactant is interpreted to mainly be due to an increased micelle-micelle repulsion. The increase in self-diffusion coefficients occurring at higher fraction of ionic surfactant is shown to be due to a decrease in micelle size. For the $C_{12}EO_8$ system, the effect of the surfactant mixing ratio is much weaker which can be understood by considering the molecular geometry and large headgroup area. The proton NMR line widths correlate well with the self-diffusion coefficients and broadening of the alkyl chain methylene signals is found when the self-diffusion coefficients is low.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.23 no.1
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• pp.43-47
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• 2012

Background and Objectives : Laryngopharyngeal reflux disease (LPRD) originates from regurgitation of gastric contents to the laryngopharynx, and it is relatively common disease in otolaryngology. Proton-pump inhibitor (PPI) medication is frequently using treatment method in present time, but controversies exist regarding treatment for it. High-resolution manometry (HRM) system is a newly developed device that using 36 channels and pressure topography plotting program, checking the function and status of esophagus. The aim of this study was to evaluate clinical usefulness of HRM in LPRD patients who do not response to PPI medication. Materials and Method : From July 2009 to July 2010, a total of 99 patients who were suspected LPRD according to symptoms (Reflux Symptom Index >13) and laryngoscopic findings (Reflux Finding Score >7) were retrospectively enrolled in this study. Patients were consisted of 31 men and 68 women, the mean age was 51.8 years, the mean BMI was 22.46. Patients have taken PPI medication for 2 months, after medication, they performed HRM. Comparative analysis was performed with results of the difference in symptoms. Results : In 99 patients, 37 patients (37.4%) show not improvement of LPRD symptoms after PPI medication. Among them, 18 patients (48.6%) showed abnormal findings that were classified as Peristaltic dysfunction (38.9%), Diffuse esophageal spasm (11.1%), Relaxation impairment of LES (11.1%), Achalasia (5.6%), Hypotensive LES (11.1%), Relaxation impairment of UES (11.1%), Nutcracker esophagus (5.6%), Decreased resting pressure (5.6%). Other 62 patients (62.6%) show improvement of LPRD symptoms, 23 patients (37.1%) showed abnormal findings. Most common finding was Peristaltic dysfunction (43.4%) More prevalent abnormal findings of HRM were found in patients who revealed no response to PPI medication (48.6% vs. 37.1%), but it does not reach the statistical significance. Conclusion : Although statistical significances is not showed, the difference observed in the frequency of HRM abnormal finding between response and no response for PPI medication. It has been estimated that HRM may be used to determine differential diagnosis in patients with LPRD. Further studies in lager population containing normal controls will be needed to prove clinical usefulness.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.22 no.2
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• pp.151-155
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• 2011

Background and Objectives : Laryngopharyngeal reflux disease (LPRD) originates from regurgitation of gastric contents to the laryngopharynx, and it is relatively common disease in otolaryngology. Proton-pump inhibitor (PPI) medication is frequently using treatment method in present time, but controversies exist regarding treatment for it. High-resolution manometry (HRM) system is a newly developed device that using 36 channels and pressure topography plotting program, checking the function and status of esophagus. The aim of this study was to evaluate clinical usefulness of HRM in LPRD patients who do not response to PPI medication. Subjects and Method : From July 2009 to July 2010, a total of 99 patients who were suspected LPRD according to symptoms (Reflux Symptom Index >13) and laryngoscopic findings (Reflux Finding Score >7) were retrospectively enrolled in this study. Patients were consisted of 31 men and 68 women, the mean age was 51.8 years, the mean BMI was 22.46. Patients have taken PPI medication for 2 months, after medication, they performed HRM. Comparative analysis was performed with results of the difference in symptoms. Results : In 99 patients, 37 patients (37.4%) show not improvement of LPRD symptoms after PPI medication. Among them, 18 patients (48.6%) showed abnormal findings that were classified as Peristaltic dysfunction (38.9%), Diffuse esophageal spasm (11.1%), Relaxation impairment of LES (11.1%), Achalasia (5.6%), Hypotensive LES (11.1%), Relaxation impairment of UES (11.1%), Nutcracker esophagus (5.6%), Decreased resting pressure (5.6%). Other 62 patients (62.6%) show improvement of LPRD symptoms, 23 patients (37.1%) showed abnormal findings. Most common finding was Peristaltic dysfunction (43.4%) More prevalent abnormal findings of HRM were found in patients who revealed no response to PPI medication (48.6% vs. 37.1%), but it does not reach the statistical significance. Conclusion : Although statistical significances is not showed, the difference observed in the frequency of HRM abnormal finding between response and no response for PPI medication. It has been estimated that HRM may be used to determine differential diagnosis in patients with LPRD. Further studies in lager population containing normal controls will be needed to prove clinical usefulness.

• Journal of radiological science and technology
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• v.26 no.2
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• pp.57-61
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• 2003

The purpose of this study is to compare both 1.5T and 4.7T in Praietal White matter material Phantom using the same methodology at both field strengths. Data at both field strengths are compared in terms of $T_2$ relaxation times, line widths and SNRs MR imaging and $^1H$ MR spectroscopy were performed on GE 1.5T SIGNA system and Broker Biospec 4.7T/30 MRI/MRS system. After phantom axial scan $^1H$ MRS was obtained from T2 weighted image by 3-dimensional localization technique(PRESS : Point RE solved spectroscopy Sequence) this phantom is composed of an aqueous solution 36.7 mmol/L of NAA, 25.0 mmol/L of Cr, 6.3 mmol/L of choline chloride, 30.0 mmol/L or Glu, and 22.5 mmol/L of MI(adjusted to a pH of 7,15 in a phosphate buffet). Data processed using software developed inhouse. At 1.5T, T2 relaxation times for Cho, Cr, and NAA were $0.41{\pm}0.07,\;0.26{\pm}0.04,\;0.46{\pm}0.07$ while at 4.7T they were $0.17{\pm}0.03,\;0.14{\pm}0.05,\;0.20{\pm}0.03$ respectively. At 1.5T, line widths for water, Cho, Cr and NAA were $2.9{\pm}0.7,\;1.6{\pm}0.7,\;1.7{\pm}0.8,\;2.2{\pm}0.02Hz$ while at 4.7T they were $5.2{\pm}1.1,\;4.6{\pm}1.9,\;4.01{\pm}1.8,\;4.8{\pm}1.9Hz$ respectively. It can be seen that $T_2$ relaxation times were significantly shorter at 4.7 compared to 1.5T and that the line widths were also broader. The average SNRs for NAA for subjects at short and long TEs were $23.5{\pm}11.3$ at TE=20 msec ; $15.4{\pm}7.7$ at TE=272 msec at 1.5T and $40{\pm}8.3$ and $17{\pm}3.5$ respectively at 4.7T higher field strength is superior because of improved sensitivity and chemical shift dispersion. However these improvements are partially offset by increased line widths and decrease $T_2$ relaxation times, which act to reduce both sensitivity and resolution. In our experiments with the equipment available to us, 4.7T proton spectra at short TEs exhibit moderately improved sensitivity compared to 1.5T.

• Progress in Medical Physics
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• v.6 no.2
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• pp.83-92
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• 1995

The T1 mapping of an human anatomy may give a characteristic contrast among the various tissues and the normal/abnormal tissues. Here, the methodology of constructing T1 map out of several images with different TRs, will be described using non-linear curve fitting. The general curve fitting algorithm requires the initial trial values T1t and Mot for the variables to be fitted. Three different methods of suppling the trial T1t and Mot are suggested and compared for the efficiency and the accuracy. The curve-fitting routine was written in ANSI C and excuted on a SUN workstation. Several distilled-water phantoms with various concentrations of Gd-DTPA were prepared to examine the accuracy of the curve-fitting program. An MR image was used as the true proton density image without any random noise, and several images with different TRs were generated with the theoretical T1 relaxation times 250, 500, and 1000msec. The random noise of 1, 5, and 10％ were embedded into the simulated images. These images were used to generate the T1 map, and the resultant T1 maps for each T1 were analyzed to study the effect of the random noise on the T1 map.