Poly[diaqua­(μ2-oxalato-κ4 O 1,O 2:O 1′,O 2′)(μ2-pyrazine-2-carboxyl­ato-κ4 N 1,O:O,O′)neodymium(III)]

In the title complex, [Nd(C5H3N2O2)(C2O4)(H2O)2]n, the NdIII atom is ten-coordinated by one N atom and three O atoms from two pyrazine-2-carboxyl­ate ligands, four O atoms from two oxalate ligands and two water mol­ecules in a distorted bicapped square-anti­prismatic geometry. The two crystallographically independent oxalate ligands, each lying on an inversion center, act as bridging ligands, linking Nd atoms into an extended zigzag chain. Neighboring chains are linked by the pyrazine-2-carboxyl­ate ligands into a two-dimensional layerlike network in the (10) plane. The layers are further connected by O—H⋯O and O—H⋯N hydrogen bonds, forming a three-dimensional supra­molecular network

Geometric bionics: Lotus effect helps polystyrene nanotube films get good blood compatibility

Various biomaterials have been widely used for manufacturing biomedical applications including artificial organs, medical devices and disposable clinical apparatus, such as vascular prostheses, blood pumps, artificial kidney, artificial hearts, dialyzers and plasma separators, which could be used in contact with blood^1^. However, the research tasks of improving hemocompatibility of biomaterials have been carrying out with the development of biomedical requirements^2^. Since the interactions that lead to surface-induced thrombosis occurring at the blood-biomaterial interface become a reason of familiar current complications with grafts therapy, improvement of the blood compatibility of artificial polymer surfaces is, therefore a major issue in biomaterials science^3^. After decades of focused research, various approaches of modifying biomaterial surfaces through chemical or biochemical methods to improve their hemocompatibility were obtained^1^. In this article, we report that polystyrene nanotube films with morphology similar to the papilla on lotus leaf can be used as blood-contacted biomaterials by virtue of Lotus effect^4^. Clearly, this idea, resulting from geometric bionics that mimicking the structure design of lotus leaf, is very novel technique for preparation of hemocompatible biomaterials

Design of Hypervelocity-Impact Damage Evaluation Technique Based on Bayesian Classifier of Transient Temperature Attributes

With the rapid increasement of space debris on earth orbit, the hypervelocity-impact (HVI) of space debris can cause some serious damages to the spacecraft, which can affect the operation security and reliability of spacecraft. Therefore, the damage detection of the spacecrafts has become an urgent problem to be solved. In this paper, a method is proposed to detect the damage of spacecraft. Firstly, a variable-interval method is proposed to extract the effective information from the infrared image sequence. Secondly, in order to mine the physical meaning of the thermal image sequence, five attributes are used to construct a feature space. After that, a Naive Bayesian classifier is established to mine the information of different damaged areas. Then, a maximum interclass distance function is used choose the representative of each class. Finally, in order to visualize damaged areas, the Canny operator is used to extract the edge of the damage. In the experiment, ground tests are used to simulate hypervelocity impacts in space. Historical data of natural damaged material and artificial damaged material are used to build different classifiers. After that, the effective of classifiers is illustrated by accuracy, F-score and AUC. Then, two different types of materials are detected by proposed method, Independent Component Analysis (ICA) and Fuzzy C-means (FCM). The results show that the proposed method is more accurate than other methods

Hemi(4,4′-bipyridinium) hexa­fluorido­phosphate bis­(4-amino­benzoic acid) 4,4′-bipyridine monohydrate

In the title compound, 0.5C10H10N2 2+·PF6 −·C10H8N2·2C7H7NO2·H2O, the cation is located on a center of symmetry. The crystal structure is determined by a complex three-dimensional network of inter­molecular O—H⋯O, O—H⋯N, N—H⋯N and N—H⋯F hydrogen bonds. π–π stacking inter­actions between neighboring pyridyl rings are also present; the centroid–centroid distance is 3.643 (5) Å. The hexa­fluoridophosphate anion is disordered over two positions with site-occupancy factors of ca 0.6 and 0.4

Preparation of a Porous Composite Film for the Fabrication of a Hydrogen Peroxide Sensor

A series of dopant-type polyaniline-polyacrylic acid composite (PAn-PAA) films with porous structures were prepared and developed for an enzyme-free hydrogen peroxide (H2O2) sensor. The composite films were highly electroactive in a neutral environment as compared to polyaniline (PAn). In addition, the carboxyl group of the PAA was found to react with H2O2 to form peroxy acid groups, and the peroxy acid could further oxidize the imine structure of PAn to form N-oxides. The N-oxides reverted to their original form via electrochemical reduction and increased the reduction current. Based on this result, PAn-PAA was used to modify a gold electrode (PAn-PAA/Au) as a working electrode for the non-enzymatic detection of H2O2. The characteristics of the proposed sensors could be tuned by the PAA/PAn molar ratio. Blending PAA with PAn enhanced the surface area, electrocatalytic activity, and conductivity of these sensors. Under optimal conditions, the linear concentration range of the H2O2 sensor was 0.04 to 12 mM with a sensitivity of 417.5 μA/mM-cm2. This enzyme-free H2O2 sensor also exhibited a rapid response time, excellent stability, and high selectivity