Development and analysis of two-dimensional point-ahead angle mechanism for space gravitational-wave detection.

To detect low-frequency gravitational waves, it is necessary to eliminate the interference of geo-noise and build a laser interference gravitational-wave detection device in space. Space gravitational-wave detection missions, namely Taiji, LISA, and Tianqin, have been planning to achieve picometer sensitivity on an interferometer arm of several million kilometers to meet the gravitational-wave detection requirements. Because of the orbit evolution and the time delay in interferometer arms, the direction of the transmitted laser beam changes; consequently, a remote telescope cannot receive the laser beam to complete the inter-satellite laser interference. In this study, a two-dimensional point-ahead angle mechanism (2DPAAM) is designed and demonstrated to solve the aforementioned problem. Based on the design concept of aligning the rotation center with the mirror surface center, the 2DPAAM employs a four-link flexible-hinge structure, length expanding and contracting piezoelectric stack actuators, and closed-loop control of capacitive sensors to realize two-dimensional picometer-stable, high-precision rotation. A static model is established to analyze the rotational characteristics, and finite element analysis is performed to study the mechanical properties and to verify the rotational characteristics. The yaw and pitch stiffness errors are ∼0.93% and 5.9%, respectively, when the theoretical results are compared with the simulation results. A series of experiments are conducted on the developed 2DPAAM, and the results show that the rotary ranges of yaw and pitch motions attain ±270 and ±268 µrad, respectively. The rotational accuracies of both yaw and pitch motions attain ∼0.35 µrad, and the optical path difference is less than 10pm/Hz when the frequency is between 1 mHz and 1 Hz, by analogy.

Rapid detection of Chinese-specific peony seed oil by using confocal Raman spectroscopy and chemometrics.

Peony seed oil (PSO) is a new woody nut oil which is unique to China. Its unsaturated fatty acids are over 90% and are rich in α - linolenic acid. Although the PSO industry is in its infancy, it is bound to become a top vegetable oil food material because of its own advantages. The potential high commercial profit of its adulteration with cheap vegetable oil will be an important factor hindering the healthy development of PSO industry. It is of great significance to study the adulteration of PSO for preventing large-scale adulteration. In this study, the qualitative and quantitative analysis of PSO was realised based on Raman spectroscopy combined with chemometrics analysis, and the fatty acid composition of PSO was analysed according to Raman characteristic peaks. The technology can be applied to routine analysis and quality control of PSO.

Role of hypothalamic cannabinoid receptors in post-stroke depression in rats.

One of the most common psychological consequences of stroke is post-stroke depression (PSD). While more than 30 percent of stroke patients eventually develop PSD, the neurobiological mechanisms underlying such a phenomenon have not been well investigated. Given the critical involvement of hypothalamic-pituitary-adrenal axis and endocannabinoid system in response to stressful stimuli, we evaluated the hypothesis that cannabinoid receptors in the hypothalamus are critical for modulation of post-stroke depression-like behaviors in rats. To this end, rats were treated with middle cerebral artery occlusion (MCAO) followed by chronic unpredictable mild stress (CUMS) treatment procedure. We then assessed the expression of CB1 and CB2 receptors in the hypothalamus, and evaluated the effects of pharmacological stimulations of CB1 or CB2 receptors on the expression and development of depression-like behaviors in PSD rats. We found that PSD rats exhibited decreased the expression of CB1 receptor, but not CB2 receptor, in the ventral medial hypothalamus (VMH). Such an effect was not observed in the dorsally adjacent brain regions. Furthermore, intra-VMH injections of CB2 receptor agonist, but not CB1 receptor agonist, attenuated the expression of depression-like behaviors in PSD rats. Finally, repeated intraperitoneal injections of CB1 or CB2 receptor agonists during CUMS treatment inhibited the development of depression-like behaviors in PSD rats. Taken together, these results suggest that decreased CB1 receptor expression is likely associated with the development of post-stroke depression, and CB2 receptor may be a potential therapeutic target for the treatment post-stroke depressive disorders.

Clinical research on comprehensive treatment of senile vascular dementia.

OBJECTIVE: To observe the curative effect of combined Chinese medicine, acupuncture and rehabilitation therapy on vascular dementia (VD), and to compare the Western medicine piracetam. METHODS: Total 134 VD patients screened in reference to the standard for VD diagnosis in DSM-IV were randomly divided into a Chinese medicine plus rehabilitation group (32 cases), a Chinese medicine plus acupuncture group (33 cases), a Chinese medicine and acupuncture plus rehabilitation group (37 cases) and a Western medicine piracetam group (32 cases). Mini Mental State Examination (MMSE) and Bless Behavior Scale (BBS) were used to assess changes in intelligence disorder before treatment and after 12-week treatment. RESULTS: BBS score, living ability and daily habit were enhanced after treatment in all groups. Cognitive function and behavioral ability were improved with similar total curative effects in all the 4 groups. Directional ability and short-term memory ability were significantly enhanced after treatment (P < 0.05) in both the Chinese medicine plus rehabilitation group and the Chinese medicine plus acupuncture group groups. Living ability was significantly improved after treatment in the Chinese medicine and acupuncture plus rehabilitation group (P < 0.01). However, no obvious difference was shown before and after treatment in the piracetam group. CONCLUSION: The improvement of living ability in the comprehensive treatment group is better than that in the other groups. Chinese medicine and acupuncture plus rehabilitation treatment can improve intelligence and living ability of senile VD patients.