RESUMO
Objective To design and experimentally validate a strobe stimulation experimental system based on LED dimming.Methods The experimental system consisted of a LED dimming system and a physiological data acquisition system.The LED dimming system was composed of a microprocessor system,a LED driver and a LED,which used pulse-width modulation(PWM)technology to modulate the duty cycle and frequency of the drive current to flexibly control the LED light intensity and flicker frequency;Biopac's 16-channel physiological signal recording and analysis system was used as the physiological data acquisition system.Strobe stimulation experiment was carried out to verify the performance of the system developed.Results The strobe stimulation experiment results showed the system developed could control the LED flicker frequency precisely and acquire the electrodermal data and ECG data of the subjects in real time,and the strobe stimulation resulted in changes of the electrodermal data and ECG data.Conclusion The system developed gains advantages in easy operation and can be used for exploring the photobiological effect of the strobe stimulation.[Chinese Medical Equipment Journal,2023,44(10):33-37]
RESUMO
<p><b>OBJECTIVE</b>To analyze the etiology of 628 patients with refractory hypertension and to observe the disease distribution with respect to gender and different age groups.</p><p><b>METHODS</b>In this study, clinical data of 628 refractory hypertensives who hospitalized in our hospital from September 1997 to December 2005 were retrospectively analyzed.</p><p><b>RESULTS</b>(1) There were 80.1% (503/628) patients with essential hypertension, 18.9% (119/628) with secondary hypertension (SH) while diagnosis was not clear in 1.0% (6/628) patients. Renovascular hypertension (33.6%) and obstructive sleep apnea syndrome (23.5%) were the major causes of SH. The highest prevalence rate of endocrine hypertension was primary aldosteronism (13.5%). (2) There were significantly more male patients than female patients with essential hypertension, SH, renal hypertension, obstructive sleep apnea syndrome, primary aldosteronism while the incidence of pheochromocytoma in female was significantly higher than that in male patients (all P < 0.05). The incidence of renovascular hypertension was similar between male and female patients. (3) SH occurred more often in young patients (33.1%) than in aged patients (13.8%, P < 0.05).</p><p><b>CONCLUSION</b>Our data from this patient cohort showed that SH, especially renovascular hypertension and obstructive sleep apnea syndrome are major causes for refractory hypertension in young patients and primary aldosteronism was the commonest reason of endocrine hypertension in youth and middle-aged patients with refractory hypertension.</p>