Fatigue crack-based strain sensors achieving flow detection and motion monitoring for reconnaissance robot applications.

Crack-based flexible strain sensors with ultra-high sensitivity under tiny strain are highly desired for environmental perception and motion detection of novel flexible and miniature robots. However, previously reported methods for fabricating crack patterns have often sacrificed the cyclic stability of the sensor, leading to a trade-off relationship between the sensitivity and the cyclic stability. Here, a universal and simple strategy based on fatigue loading with an ultra-large cumulative strain of up to ∼1.2 × 107%, rather than the traditionally quasi-static pre-overloading methods, is proposed to introduce channel cracks in the sensing layer without sacrificing the cyclic stability. The developed flexible strain sensors exhibit high strain-sensitivity (gauge factor = 5798) under tiny strain (< 3%), high cyclic stability (15 000 cycles) and a low strain detecting limit (0.02%). Furthermore, a leaf-like mechanosensor is developed using the fatigue crack-based strain sensor for the realization of multifunctional applications in environment perception and micro-motion detection. Brilliant airflow sensing performance with a wide sensing range (0.93-11.93 m s-1) and a fast response time (0.28 s) for amphibious applications is demonstrated. This work provides a new strategy for overcoming limits of crack-based flexible strain sensors and the developed leaf-like mechanosensor shows great application potential in miniature and flexible reconnaissance robots.

Effects of methyl oleate and microparticle-enhanced cultivation on echinocandin B fermentation titer.

Echinocandin B (ECB) is a key precursor of antifungal agent Anidulafungin, which has demonstrated clinical efficacy in patients with invasive candidiasis. In this study, the effects of microparticle-enhanced cultivation and methyl oleate on echinocandin B fermentation titer were investigated. The results showed that the titer was significantly influenced by the morphological type of mycelium, and mycelium pellet was beneficial to improve the titer of this secondary metabolism. First, different carbon sources were chosen for the fermentation, and methyl oleate achieved the highest echinocandin B titer of 2133 ± 50 mg/L, which was two times higher than that of the mannitol. The study further investigated the metabolic process of the fermentation, and the results showed that L-threonine concentration inside the cell could reach 275 mg/L at 168 h with methyl oleate, about 2.5 times higher than that of the mannitol. Therefore, L-threonine may be a key precursor of echinocandin B. In the end, a new method of adding microparticles for improving the mycelial morphology was used, and the addition of talcum powder (20 g/L, diameter of 45 µm) could make the maximum titer of echinocandin B reach 3148 ± 100 mg/L.

[Elucidation of the national standard for Standardized Manipulation of Acupuncture and Moxibustion, Part VII: Skin needle].

The importance of standardization, the main content and important cautions in the Standardized Manipulation of Acupuncture and Moxibustion, Part VII: Skin Needle are introduced briefly in this paper. It standardizes the stimulation intensity, the tapped needling location, the course of treatment and the interval between treatments. It elucidates the key points, the difficulty and the important cautions in clinical practices. In order to promote the standardization and its implementation, it also states the experiences of establishing the national standard of acupuncture and moxibustion manipulations.

[Influence of electroacupuncture of "Daling"(PC 7) on heart rate, duration of arrhythmia and plasma vasoactive intestinal peptide contents in ventricular tachycardia rats].

OBJECTIVE: To observe the effect of electroacupuncture (EA) on heart rate (HR), arrhythmia duration, and plasma vasoactive intestinal peptide (VIP) level in ventricular tachycardia (VT) rats so as to study its underlying adjustment mechanism. METHODS: A total of 70 SD rats were randomly divided into normal control, model (VT), "Daling" (PC 7, EA-PC 7) and "Taiyuan" (LU 9, EA-LU 9) groups. VT model was duplicated by injection of CsCI (2 mol/L, 1.6 mmoL/kg, femoral vein). EA (2 Hz/15 Hz, 1 mA) was applied to "Daling" (PC 7) and "Taiyuan" (LU 9) for 5 min after inserting acupuncture needles. BL-410 Biofunctional System was used to record the ECG of the standard limb lead II, and plasma VIP content assayed by using radioimmunoassay. RESULTS: Following intravenous injection of CsCI, HR increased significantly in model, EA-PC 7 and EA-LU 9 groups (P < 0.05). Compared to model group, HR at 5 min, 10 min and 15 min after administration of CsCI and the duration of arrhythmia in EA-PC 7 group decreased considerably (P < 0.01). No significant differences were found between EA-LU 9 and model groups in HR and the duration of arrhythmia (P > 0.05). Compared with normal group, the content of plasma VIP in model group decreased apparently (P < 0.05), while in comparison with model group, plasma VIP level in EA-PC 7 group increased considerably (P < 0.01). CONCLUSION: Electroacupuncture of "Daling" (PC7) can effectively suppress CsCI-induced tachycardia which may be closely associated with its effect in reducing plasma VIP level.

[Effect of electroacupuncture of "Neiguan" (PC 6) on heart rate and plasma catecholamine contents in ventricular tachycardia rats].

OBJECTIVE: To observe the effect of electroacupuncture (EA) of "Neiguan" (PC 6) on heart rate (HR) and plasma catecholamine (CA) levels in ventricular tachycardia (VT) rats. METHODS: A total of 50 SD rats were randomly divided into normal control, sham-operation (sham), model, EA-PC 6 and EA-LU 7 groups, with 10 cases in each. VT model was established by intravenous injection of cesium chloride (CsCl) via femoral vein. Electrocardiogram (ECG) was recorded. EA (2 Hz/15 Hz, 1 mA) was separately applied to bilateral "Neiguan" (PC 6) and "Lieque" (LU 7) for 5 minutes, followed by collecting blood samples for detecting plasma norepinephrine (NE) and epinephrine (E) levels with fluorometric method. RESULTS: In comparison with normal control group, plasma NE and E contents in model group increased apparently (P < 0.01). Compared with model group, HR and plasma NE and E contents of EA-PC 6 group reduced significantly (P < 0.01), while those of EA-LU 7 had no apparent change (P > 0.05). CONCLUSION: EA of "Neiguan" (PC 6) can downregulate heart rate and plasma CA level in VT rats, which may contribute to its effect in relieving tachycardia.

[Influence of electroacupuncture of "Shuigou" (GV 26) on hippocampal CGRP and NPY contents in cerebral ischemia rats].

OBJECTIVE: To observe the effect of electroacupuncture (EA) on the contents of hippocampal calcitonin gene-related peptide (CGRP) and neuropeptide Y (NPY) in cerebral ischemia (CI) rats. METHODS: Forty SD rats were randomly divided into normal control, sham operation (sham), model and EA groups with 10 cases in each. CI model was duplicated by middle cerebral artery occlusion. EA (2 Hz, 1 mA, continuous waves) was applied to "Shuigou" (GV 26) for 30 min, once daily for 5 days. Hippocampal tissue was taken for assaying the contents of CGRP and NPY with radioimmunoassay. RESULTS: Compared with sham group and normal control group, hippocampal CGRP content in model group decreased apparently (P<0.01), while NPY content of model group increased significantly (P<0.01). Compared with model group, hippocampal CGRP in EA group increased considerably (P<0.01) and NPY content decreased obviously (P<0.01). CONCLUSION: Electroacupuncture of GV26 can effectively adjust hippocampal CGRP and NPY contents in CI rats, which may contribute to its effect in improving cerebral ischemia.

[Study on dual-directional regulation induced by acupuncture at different acupoints in the rat with motility abnormality of the stomach].

OBJECTIVE: To probe into the bidirectional regulation of acupuncture in the rat with motility abnormality of the stomach and the nerve mechanism. METHODS: Adopting electrophysiological methods, the extracellular discharge signals of neuronic action in NTS were recorded with glass microelectrodes. The effects of acupuncture at "Zusanli" (ST 36), "Neiguan" (PC 6), "Zhongwan" (CV 12), "Qihai" (CV 6) on discharges of NTS neurons and intra-gastric pressure were observed in the rat at normal physiological state, and increase or reduction of gastric motility. RESULTS: Acupuncture at "Zusanli" (ST 36), "Neiguan" (PC 6) could significantly promote gastric motility of the rat at normal status, increase or reduction of gastric motion, while acupuncture at "Zhongwan" (CV 12), "Qihai" (CV 6) could significantly inhibit gastric motion. And acupuncture at all the above acupoints could activate discharges of NTS neurons. CONCLUSION: The bidirectional regulation effect of an acupoint does not certainly indicate that the same point has bidirectional regulation effect on an internal organs at different pathological states, while this may show synthetic action of different points which is a good regulation towards normal states and homeostasis.

[The role of endogenous opioid peptides in paraventricular nucleus of hypothalamus in the antagonism to myocardial ischemia by electroacupuncture at acupoint "Neiguan" (PC 6)].

OBJECTIVE: To explore the mechanism of electroacupuncture at "Neiguan" (PC 6) antagonizing myocardial ischemia injury. METHODS: Forty rabbits were randomly divided into 4 groups, model control group, naloxone control group, electroacupuncture plus cerebral spinal fluid group, and electroacupuncture plus naloxone group, 10 rabbits in each group. The effects of electroacupuncture at "Neiguan" (PC 6) after injection of naloxone into the paraventricular nucleus (PVN) of the hypothalamus on myocardial ultrastructure, II lead ECG and transmembrane potentials of the ischemic myocardial cell in the rabbit of myocardial ischemia were investigated. RESULTS: The injection of naloxone into PVN has no effect on myocardial functions in the normal rabbit and a little effect on ischemic myocardial functions, but at 60 min after myocardial ischemia, this has a certain protective action on myocardial functions (P < 0.05); electroacupuncture at "Neiguan" has obvious protective action on ischemic myocardium, which can be reduced by injection of naloxone into PVN (P < 0.05), but can not be blocked. CONCLUSION: (1) PVN plays an important role in the process of antagonizing myocardial ischemia by electroacupuncture at "Neiguan"; (2) endogenous opioid pepetides in PVN are involved in the acupuncture effect of antagonizing myocardial ischemia; (3) other transmitters in PVN and other nucleus groups in the center also can produce obvious effects in the antagonism to myocardial ischemia by electroacupuncture at "Neiguan".

[Determination of the catalytic structures of methyl parathion hydrolase].

Methyl parathion hydrolase (MPH) is a novel member of organophosphorus hydrolase. In this study, mpd gene was expressed in Escherichia coli DH5alpha with its native promoter. MPH was purified to homogeneity. Results show that metal-chelating compounds cannot inhabit the enzyme activity. Inductively Coupled Plasma-Atomic Emission Spectrometry analysis showed that MPH is a zinc-containing enzyme, the Zinc to enzyme molar ratio is near 2:1. In order to investigate critical residues related to enzymatic activity of MPH, chemical modification reagents EDC, DEPC, butanedione and pyridoxal were tested. Experiment results suggested that aspartate, glutamate, arginine and lysine are not important for enzyme activity. But DEPC, which can modify histidine residue, inactivate the enzyme activity greatly, and the inactivation rate is 9.6 h(-1). This result reflects that histidine residues are essential for enzyme activity. All these results provide basic data for MPH structure and molecular evolution research.