5,8-Dibromo-15-cyano-2,11-dithia­[3.3]paracyclo­phane

In the title compound [systematic name: 13,15-dibromo-3,10-dithia­tricyclo­[10.2.2.25,8]octa­deca-1(14),5,7,12,15,17-hexa­ene-6-carbonitrile], C17H13Br2NS2, the mean planes of the benzene rings are almost parallel, making a dihedral angle of 1.1 (2)°, and the distance between the ring centroids is 3.294 (3) Å, which is shorter than the normal packing distance of aromatic rings (about 3.4 Å), indicating a strong π–π inter­action. The S atom of one bridging chain is disorderd over two positions with site occupancies of 0.605 (4) and 0.395 (4) for the major and minor components, respectively

Fault diagnosis of refrigerant charge based on PCA and decision tree for variable refrigerant flow systems

Variable refrigerant flow (VRF) systems are easily subjected to performance degradation due to refrigerant leakage, mechanical failure or improper maintenance after years of operation. Ideal VRF systems should equip with fault detection and diagnosis (FDD) program to sustain its normal operation. This paper presents the fault diagnosis method for refrigerant charge faults of variable refrigerant flow (VRF) systems. It is developed based on the principal component analysis (PCA) feature extraction method and the decision tree (DT) classification algorithm. Nine refrigerant charge schemes are implemented on the VRF system in the laboratory, which contain the normal and faulty refrigerant charge conditions. In addition, data of the online operating VRF systems are collected in this work. Firstly, data from both experimental VRF system and online operating systems are pre-processed by outlier cleaning, feature extraction and data normalization, because the original data of the VRF system usually has poor quality and complex structure. Secondly, the fault diagnosis model based on the PCA-DT method is built using the data of the experimental VRF system. In this step, the PCA method is used to obtain a new data sample which includes four comprehensive features, then the new data sample are randomly split into training and testing sets as the input of DT classifier for fault diagnosis. Thirdly, the advantages of the PCA-DT method is validated using the experimental data of different fault severity levels. Results show that the combined use of PCA and DT methods can achieve better fault diagnosis efficiency than the single decision tree method. Further, the robustness of the PCA-DT method in online fault diagnosis is verified using the data from online VRF systems. The online VRF systems have the same or different number of indoor units as the trained (experimental) VRF system. The PCA-DT method also shows desirable goodness on the online fault diagnosis process. In this sense, this work provides a promising fault diagnosis strategy for refrigerant charge faults of VRF system application

Anti-osteoporosis effect of Notopterygium incisum Ting ex H. T. Chang extract in rats

Purpose: To investigate the effect of Notopterygium incisum Ting ex H.T. Chang extract (NICE) on ovariectomy-induced osteoporosis in rats. Methods: Female Sprague-Dawley rats were randomly assigned to a normal group (control) and five ovariectomy (OVX) subgroups: OVX with vehicle (OVX), OVX with positive control drug alendronate sodium tablets (1.8 mg/kg/week), and OVX with varying NICE doses (45, 90, or 180 mg/kg/day). After rats were subjected to ovariectomy for 4 weeks, alendronate or NICE were administered orally daily for 16 weeks. The bone mineral density (BMD) of the L4 vertebrae and right femurs of all rats was estimated. The serum hormones estradiol (E2), follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels and serum alkaline phosphatase (ALP), osteocalcin (OC) and telopeptides of collagen type I (CTx) levels of rats were detrmined. Results: The results show that NICE dose-dependently inhibited bone mineral density (BMD) reduction of L4 vertebrae and femurs (p < 0.05). Compared with OVX group, serum E2, FSH and LH levels was significantly increased in osteoporosis rats (p < 0.01), but serum ALP, CTx, and OC concentrations were significantly lower (p < 0.05). On the other hand, bone trabeculae in the three NICE groups and nilestriol group were all wider, while the space and connections increased. Conclusion: These findings indicate that NICE mitigates OVX-induced osteoporosis in rats, and hence can potentially be developed for the management of osteoporosis

Airport pavement performance evaluation of pavement fog seal based on optimized test technology

Fog seal technology is widely used in airport asphalt pavement. The research on the performance and application of fog seal material is basically at the level of modified emulsified asphalt. The fog seal test method in the existing specification has defects. Three kinds of fog seal materials with different substrates were selected in this paper. Based on the characteristics of fog seal treatment and the relevant specifications of fog seal and airport pavement. Wet Track Abrasion Test (WTAT), Cantabro test, Water seepage test, and Pendulum instrument tester pavement friction coefficient test were improved. Test the pavement performance of different types of fog seals. The results show that the mass loss of material C was less than 10% after 200 and 400 cycles of wear. The improvement effect of material C on raveling resistance and impermeability was far better than that of materials A and B. The improvement of material C on the raveling resistance of the mixture could reach 50%. The immediate improvement effect on the impermeability was nearly 100%. The skid resistance performance of the three fog seal materials decreased after treatment. The decrease in material C was more significant than in materials A and B. In constructing material C, the dose of emery should be appropriately increased. It was advisable to not be less than 0.35 kg/m2. The fog seal layer improves pavement performance. It has reference significance for using fog seal technology to treat early airport pavement diseases

Lightweight conductive graphene/thermoplastic polyurethane foams with ultrahigh compressibility for piezoresistive sensing

Lightweight conductive porous graphene/thermoplastic polyurethane (TPU) foams with ultrahigh compressibility were successfully fabricated by using the thermal induced phase separation (TISP) technique. The density and porosity of the foams were calculated to be about 0.11 g cm−3 and 90% owing to the porous structure. Compared with pure TPU foams, the addition of graphene could effectively increase the thickness of the cell wall and hinder the formation of small holes, leading to a robust porous structure with excellent compression property. Meanwhile, the cell walls with small holes and a dendritic structure were observed due to the flexibility of graphene, endowing the foam with special positive piezoresistive behaviors and peculiar response patterns with a deflection point during the cyclic compression. This could effectively enhance the identifiability of external compression strain when used as piezoresistive sensors. In addition, larger compression sensitivity was achieved at a higher compression rate. Due to high porosity and good elasticity of TPU, the conductive foams demonstrated good compressibility and stable piezoresistive sensing signals at a strain of up to 90%. During the cyclic piezoresistive sensing test under different compression strains, the conductive foam exhibited good recoverability and reproducibility after the stabilization of cyclic loading. All these suggest that the fabricated conductive foam possesses great potential to be used as lightweight, flexible, highly sensitive, and stable piezoresistive sensors

Efficacy and safety of tetramethylpyrazine phosphate on pulmonary hypertension: study protocol for a randomized controlled study

Background: Tetramethylpyrazine (TMP), an active ingredient in the traditional Chinese herbal medicine Rhizoma Chuanxiong, has been used clinically for the prevention and treatment of cardiovascular disease. The benefits of TMP are largely attributed to its anti-oxidative and vasodilative properties. However, the efficacy of TMP in the treatment of pulmonary hypertension (PH) is unknown. We hypothesized that TMP may have a therapeutic effect in patients with PH. Methods/design: A randomized, single-blinded, clinical study with a TMP treatment group and a control group will be conducted to evaluate the efficacy and safety of TMP intervention in patients with PH. The recruitment target is 120 subjects meeting the following criteria: (i) at rest and at sea level, mean pulmonary artery pressure above 20 mmHg and pulmonary capillary wedge pressure below 15 mmHg; (ii) type 1 or 4 PH in the stable phase; (iii) age 15-70 years; (iv) 6-min walk distance between 100 and 450 m; (v) World Health Organization (WHO) functional classification of pulmonary hypertension of II, III, or IV. Subjects will be assigned randomly into two groups at a ratio of 1:2 (control:TMP). Both groups will receive routine treatment, and the treatment group will also receive oral TMP (100 mg) three times a day for 16 weeks. All patients will be followed up for 4, 8, 12, and 16 weeks; symptoms and patient compliance will be recorded. Discussion: We aimed to determine the efficacy and safety of TMP for the treatment of PH.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Knocking out ACR2 does not affect arsenic redox status in Arabidopsis thaliana: implications for As detoxification and accumulation in plants

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