Two-D liquid velocity field in a tube with a combination of a stenosis and a bifurcation was measured with refractive index matching technique using Laser Doppler Velocimeter (LDV). The flow ratio of main tube to bypass was 1:4. It is found that the axial velocity profile has two peaks in the XOY plane which is skewed to the main tube wall facing the flow from the bypass, and it manifests itself in the form of "M" in the XOZ plane. A two counter-rotating vortices in the main tube cross section downstream the conjunction region is also detected.
Laser-Doppler Flowmetry ; instrumentation ; methods ; Rheology

BACKGROUND AND OBJECTIVES: The effects of airflow cessation on the human nasal mucosa can be conveniently studied in laryngectomees and the blood flow to nasal mucosa is an important factor in maintaining normal nasal function. Therefore, we investigated the changes in nasal mucosa blood flow after a total laryngectomy with Laser Doppler flowmetry. MATERIALS AND METHOD: Twenty-four laryngectomees were studied and compared with 35 normal volunteers. Among 24 total laryngectomees, 9 were esophageal speakers. The Laser Doppler flowmetry was performed using a Periflux 4001 (Perimed, Jrtlla, Sweden) and Perfusion unit (PU), Velocity unit (VU), and Concentration Unit (CU) were measured. The laser Doppler flowmetry data in the laryngectomees were compared with those of the normal subjects, and between the esophageal and non-esophageal speakers. RESULTS: The difference between laryngectomees and normal subjects was statistically significant with the exception of the CU (p<0.05). Furthermore, no correlations were found between blood flow and age, and between blood flow and postoperative duration. The difference between esophageal speakers and non-esophageal speakers was statistically significant with the exception of the level of concentration (p<0.05). CONCLUSION: The nasal blood flow decreased after a total laryngectomy. When airflow improved, an increase in the level of blood flow was recorded. And the change of the nasal blood flow most likely occured within the first year after a total laryngectomy.
Healthy Volunteers ; Humans ; Laryngectomy* ; Laser-Doppler Flowmetry ; Nasal Mucosa ; Perfusion ; Rheology*

Confocal scanning laser flowmetry(HRF: Heidelberg Retina Flowmetry) is a new kind of instrument which enables non-invasive two-dimentional mapping of perfusion of the retina and optic disc and to evaluate the clinically available reproducibility of the peripapillary and retinal perfusion measurement with the confocal scanning laser flowmetry, the authors calculate the coefficient of variation (CV) from the parameters(volume, flow, velocity). The authors indicate two region of interest in the peripapillary region and retina, not overlapping the large vessels and measure the parameters three times consecutively(one session) while visiting three times intervalled(three session), thereafter calculate the mean CV of parameters in ten healthy eyes of ten subject. The CV of parameters obtained with the confocal scanning laser flowmetry was low relatively and therefore reproducibility was high as the CV lower, the reproducibility higher. Comparing the CV between one session and three session measurement to know the clinically available measurement frequency, the CV of three session (volume 13%, flow 16.7%, velocity 16%) was lower than the CV of one session (volume 16.7%, flow 20.7%, velocity 20.1%) in the peripapillary region(Students t test; volume p=0.009, flow p=0.03, velocity p=0.016) and the CV of three session (volume 16.7%, flow 20.7%, velocity 17%) was lower than the CV of one session (volume 18.2%, flow 21.8%, velocity 21.7%) in the retina(Students t test; volume p=0.017, flow p=0.0009, velocity p=0.0004). Above the results, the CV of parameters(13~21.8%) in one and three session had relatively high reproducibility. Also the CV between two measurements had a difference statistically but the difference was not so high, the authors concluded the confocal scanning laser flowmetry which have high resolution measure the peripapillary region and retina reproduciblly with only one time visit, three consecutive measurements.
Perfusion* ; Retina ; Retinaldehyde* ; Rheology*

No abstract available.
Biometry* ; Rheology* ; Umbilical Arteries*

No abstract available.
Pregnancy* ; Rheology* ; Uterine Artery*

STATEMETN OF PROBLEM: The viscoelastic property is the most important and peculiar charac-teristics of soft liners. But the authorized standard is not certainly established than other den-tal materials. PURPOSE OF STUDY: This study is aimed to compare the initial flow of gelation of the modified soft liner with 4-META with that of PMMA soft liners using dynamic method and evaluate the clinical acceptance of the trial materials. MATERIAL AND METHOD: This study consists of 3 groups with the given % of 4-META powder in the Coe soft liquid; 0%, 5%, 10% Each group was tested for 10 times to record the change of G'values during 3 hours. the gelation time was recorded by the oscillating rheometer with parallel plate with 1 rad/sec. RESULTS: As the results of this study, the gelation time of modified soft liner was elongated by 5 to 6 minutes. CONCLUSION: The mean gelation time of modified soft liner could be within the range of clin-ically acceptable.
Polymethyl Methacrylate ; Rheology*

No abstract available.
Rheology* ; Umbilical Arteries*

In evaluating the cardiac function, it is important to have a comprehensive assessment of structural factors, such as the myocardial or valvular function and intracardiac flow dynamics that pass the heart. Vortex flow that form during left ventricular filling have specific geometry and anatomical location that are critical determinants of directed blood flow during ejection. The formation of abnormal vortices relates to the abnormal cardiac function. Therefore, vortex flow may offer a novel index of cardiac dysfunction. Intracardiac flow visualization using ultrasound technique has definite advantages with a higher temporal resolution and availability in real time clinical setting. Vector flow mapping based on color-Doppler and contrast echocardiography using particle image velocimetry is currently being used for visualizing the intracardiac flow. The purpose of this review is to provide readers with an update on the current method for analyzing intracardiac flow using echocardiography and its clinical applications.
Echocardiography* ; Heart ; Rheology ; Ultrasonography

The study aimed to determine the optimal mixing ratio of two different amounts of Letinus edodes powder and egg for preparation of pasta. The complete analysis was conducted using the Design Expert 7 program (State-Easy, Minneapolis, MN). Response surface methodology revealed 10 experimental points, including two replicates for L. edodes powder and egg. L. edodes pasta formulation was optimized using rheology. Lightness and redness displayed a lineal model pattern, whereas yellowness was represented by a quadratic model. The sensory evaluation parameters of texture, color, flavor, appearance and overall quality showed significant differences for color (p<0.01), flavor (p<0.05), texture (p<0.05) and overall quality (p<0.05). All sensory parameters showed significant values in a quadratic model. The optimum formulations processed by numerical and graphical optimization were determined as 15 g of L. edodes powder and 37.5 g of egg.
Light ; Ovum ; Rheology

No abstract available.
Pregnancy* ; Rheology* ; Uterine Artery*