Metoprolol has a similar therapeutic effect as amlodipine on BP lowering in hypertensive patients with obstructive sleep apnea.

PURPOSE: ß-Blocker use has been controversial for a long time in the management of hypertensive patients with obstructive sleep apnea (OSA). The aim of present study was to compare the effects of metoprolol on BP lowering with amlodipine in hypertensive OSA patients. METHODS: Hypertensive subjects with OSA were randomly assigned to metoprolol and amlodipine groups, receiving 12 weeks of oral either metoprolol (47.5 mg once daily) or amlodipine (5 mg once daily) treatment. At baseline and after the 12-week treatment period, 24-h ambulatory blood pressure monitoring was performed in both groups. RESULTS: Both of metoprolol and amlodipine treatments significantly lowered 24-h blood pressure (BP) (from 143/88 to 132.3/81.6 mmHg; from 141.3/84.5 to 133.7/80.8 mmHg), daytime BP (from 146/90.2 to 136.4/84.6 mmHg; from 145.1/87.6 to 138.2/84.1 mmHg), and nighttime BP (from 139.1/83.9 to 125.7/76.2 mmHg; from 134.5/78.5 to 125.8/74.1 mmHg) (all P < 0.05). But there were no significant differences between the groups in BP variability (P > 0.05). Besides, metoprolol significantly reduced daytime heart rate (HR) (P < 0.05), while 24-h and nighttime HR values had no remarkable changes compared with baseline (P > 0.05). CONCLUSIONS: Metoprolol had similar therapeutic effects on BP lowering as amlodipine and could not decrease HR during the nighttime in hypertensive patients with OSA.

Enhanced photocatalytic efficiency of C3N4/BiFeO3 heterojunctions: the synergistic effects of band alignment and ferroelectricity.

As one of the most promising photocatalysts, graphitic carbon nitride (g-C3N4) shows a visible light response and great chemical stability. However, its relatively low photocatalytic efficiency is a major obstacle to actual applications. Here an effective and feasible method to dramatically increase the visible light photocatalytic efficiency by forming C3N4/BiFeO3 ferroelectric heterojunctions is reported, wherein the band alignment and piezo-/ferroelectricity have synergistic positive effects in accelerating the separation of the photogenerated carriers. At the optimum composition of 10 wt% BiFeO3, the heterojunction shows 1.4 times improved photocatalytic efficiency than that of the pure C3N4. Most importantly, mechanical pressing and electrical poling can also improve the photocatalytic efficiencies by 1.3 times and 1.8 times, respectively. The optimized photocatalytic efficiency is even comparable with that of some noble metal based compounds. These results not only prove the improved photocatalytic activity of the C3N4-ferroelectric heterojunctions, but also provide a new approach for designing high-performance photocatalysts by taking advantage of ferroelectricity.

Obstructive sleep apnea increases systolic and diastolic blood pressure variability in hypertensive patients.

OBJECTIVE: Obstructive sleep apnea (OSA) has been identified as the most common secondary contributing factor for the development and worsening of hypertension. However, the underlying relationships between blood pressure variability (BPV) and OSA are still not very clear. Therefore, we investigated the influences of OSA on BPV in hypertensive patients and explored the potential pathophysiologic mechanisms. PARTICIPANTS AND METHODS: Ambulatory blood pressure (BP) monitoring was carried out and polysomnography was performed to detect sleep apnea. A total of 86 hypertensive individuals were divided into patients without OSA (n=43) and patients with severe OSA (n=43). Systolic and diastolic BPV were obtained by calculating the SD, coefficient of variation, and average real variability during day-time, night-time, and over 24 h. The relationship between OSA and BPV was assessed after adjustment for potential confounding variables (age, sex, BMI, neck circumference, heart rate, and snoring history). RESULTS: Compared with participants without OSA, nocturnal systolic BPV and 24-h systolic BP average real variability from OSA participants were obviously increased (P<0.05), but there were no statistically significant differences in day-time and 24-h systolic BP SD and coefficient of variation (P>0.05). Compared with participants without OSA, 24-h diastolic BPV and day-time diastolic BP SD from OSA participants were markedly increased (P<0.05), but nocturnal indices showed no significant differences between the two groups. CONCLUSION: OSA mainly increases night-time systolic and 24-h diastolic BPV in hypertensive patients. This may provide a plausible explanation for OSA remaining a major risk determinant for cardiovascular diseases.