[Quantification of antigen of Mycoplasma capricolum subsp. capripneumoniae by optical assay].

Mycoplasma capricolum subsp. capripneumoniae (Mccp) is the cause of contagious caprine pleuropneumonia (CCPP) in goats. Inactivated vaccines and capsular polysaccharide (CPS) indirect hemagglutination reagents are available for prevention and serological detection, but high culture costs and complex antigen quantification have been plagued by production staff. In order to solve these problems in production practice, a sugar fermentation medium with an initial pH value of 7.8, which could improve the production of two antigens simultaneously, was screened out by changing the initial pH value based on previous Mccp metabolomics analysis. Since phenol red can be identified by UV absorption spectrum and cetyltrimethylammonium bromide (CTAB) can bind to anionic capsular polysaccharide, a UV spectrum measurement method for analyzing the culture stage reached by Mccp and a CTAB precipitation test for relative quantification of capsular polysaccharide antigen content in the fermentation broth were established. The UV spectrum observation method can guide the production of Mccp according to the growth curve of Mccp, which greatly reduces the monitoring time of the traditional CCU method and improves the accuracy of the original eye-observation method. The established CTAB precipitation test can complete the monitoring of CPS content within 5 hours, which greatly reduces the time required compared with the traditional differential technique, and its accuracy was verified by the phenol-sulfuric acid method. The optimized culture medium and the two correlation comparison methods established in this study can effectively reduce the production cost of Mccp and improve the production efficiency. The two assays have been used in the research at our laboratory, which provides experimental data for further improvement of the production process of CCPP inactivated vaccine and capsular polysaccharide as well as rapid quantification.

Homochiral Chemistry Strategy To Trigger Dielectric Switching and Second-Harmonic Generation Response on Spirocyclic Derivatives.

Organic-inorganic hybrid materials with switchable properties have significant potential applications in intelligent devices. There are some conventional ways to obtain optical and/or electric multiple responses, such as asymmetric design, chirality, doping, and structural dimension in hybrid materials. Among them, the homochirality strategy is one of the best ways to regulate the molecular structure and symmetry, thereby ensuring second-harmonic generation (SHG) and dielectric dual response characteristics. Here, we report a homochiral design strategy to obtain noncentrosymmetric [R-(HASD)][Cd(SCN)3] (HASD = 7-hydroxy-5-azaspiro[4.5]decan) and [S-(HASD)][Cd(SCN)3]; [Rac-(HASD)][Cd(SCN)3] was also synthesized as a comparative experiment to illustrate the relationship between structural chirality and physical properties. With the help of homochiral regulation, the SHG response is excited and dielectric phase transition temperature (Tc) is also highly improved. In addition, both the optical SHG and dielectric phase change show an optical/electric switchable response. This work is of great significance for the further exploration of multifunctional molecular switching materials through homochiral chemistry.

In Situ Observation of Ferroelastic Domain and Phase Transition in a Three-Dimensional Molecular Crystal.

Massive efforts have been devoted to designing molecular ferroic materials by molecular modification. For molecular ferroelastic, previous work is focused on the temperature-dependent ferroelastic domains, however, few are related to controlling the ferroelastic domain by the stress. Inspired by the "quasi-spherical theory" and fluorination effect, we designed a more flexible (MedabcoF)2+ (MedabcoF=1-fluoro-4-methyl-1,4-diazoniabicyclo[2.2.2]octane) cation by introducing a methyl group and a fluorine atom at the two symmetrical ends of the Dabco (1,4-diazoniabicyclo[2.2.2]octane) and synthesized a hybrid 3D perovskite (MedabcoF)Rb(BF4 )3 (1) which displays three reversible phase transitions accompanying dual ferroelastic behavior. Besides, it not only exhibits ferroelastic domains switching by the thermal stimulation, and the sensitive reaction of in situ domains under the stress of it is also realized. This work not only achieves a force-controlled ferroelastic domain but develops a more profound comprehension of the relationship between the thermal motion behavior of guest cations and the intriguing properties of materials.

Two-Dimensional Layered Perovskite Ferroelectric with Giant Piezoelectric Voltage Coefficient.

Piezoelectric sensors that can work under various conditions with superior performance are highly desirable with the arrival of the Internet of Things. For practical applications, a large piezoelectric voltage coefficient g and a high Curie temperature Tc are critical to the performance of piezoelectric sensors. Here, we report a two-dimensional perovskite ferroelectric (4-aminotetrahydropyran)2PbBr4 [(ATHP)2PbBr4] with a saturated polarization of 5.6 µC cm-2, high Tc of 503 K [above that of BaTiO3 (BTO, 393 K)], and extremely large g33 of 660.3 × 10-3 V m N-1 [much beyond that of Pb(Zr,Ti)O3 (PZT) ceramics (20 to 40 × 10-3 V m N-1), more than 2 times higher than that of poly(vinylidene fluoride) (PVDF, about 286.7 × 10-3 V m N-1)]. Combined with the advantages of molecular ferroelectrics, such as light weight, easy and environmentally friendly processing, and mechanical flexibility, (ATHP)2PbBr4 would be a competitive candidate for next-generation smart piezoelectric sensors in flexible devices, soft robotics, and biomedical devices.

Sequential dielectric phase transitions induced by the vibrations of water molecules in an organic-inorganic hybrid halide (N-(2-ammoniumethyl)piperazinium) CuCl5·2H2O.

Organic-inorganic hybrids represent a new type of material showing promising properties. In this report, sequential dielectric transitions have been studied in an organic-inorganic hybrid halide, (N-2-AP)CuCl5·2H2O (N-2-AP = N-(2-ammoniumethyl)piperazinium) (1). The packing structure of 1 displays discrete [CuCl5]3- rectangular pyramids and N-2-AP cations, which are linked by two water molecules, forming infinite hydrogen bond networks with inorganic and organic components along the b-axis. Characterization studies containing differential scanning calorimetry (DSC) measurements, variable-temperature X-ray diffraction and dielectric measurements were performed to investigate the phase transitions in 1. The deuterated sample of 1 (named 2) also exhibits a similar behavior to that in 1, but shows different phase transition temperatures in dielectric transitions. The arresting deuterated effect strongly confirms that the phase transitions in 1 are attributable to the local vibrations of water molecules resulting from the variation of hydrogen-bonding interactions.

Controllable Structures Designed with Multiple-Dielectric Responses in Hybrid Perovskite-Type Molecular Crystals.

In this report, two new hybrid organic-inorganic perovskite-type compounds, (IBA)CdBr3 (1; IBA = isobutylammonium cation, i-C4H9-NH3) and (IBA)2CdBr4 (2), have been successfully synthesized by reasonable modulation of the ratio of the reactants. 1 with a one-dimensional (1D) chained structure presents sequential solid-state phase transitions, and 2 with a two-dimensional (2D) layered structure undergoes triple structural phase transitions. The phase transitions are attributable to the stepwise ordering process of the organic IBA cation of the title compounds, which also exhibit temperature-dependent dielectric transitions and dielectric anisotropies. Among the different structural environments, the dynamic motions of organic cations show distinct differences, driving the variation of physical properties.

Molecular Ferroelectric with Most Equivalent Polarization Directions Induced by the Plastic Phase Transition.

Besides the single crystals, ferroelectric materials are actually widely used in the forms of the polycrystals like ceramics. Multiaxial ferroelectrics with multiple equivalent polarization directions are preferable for such applications, because more equivalent ferroelectric axes allow random spontaneous polarization vectors to be oriented along the electric field to achieve a larger polarization after poling. Most of ceramic ferroelectrics like BaTiO3 have equivalent ferroelectric axes no more than three. We herein describe a molecular-ionic ferroelectric with 12 equivalent ferroelectric axes: tetraethylammonium perchlorate, whose number of axes is the most in the known ferroelectrics. Appearance of so many equivalent ferroelectric axes benefits from the plastic phase transition, because the plastic phase usually crystallizes in a highly symmetric cubic system. A perfect macroscopic ferroelectricity can be obtained on the polycrystalline film of this material. This finding opened an avenue constructing multiaxial ferroelectrics for applications as polycrystalline materials.

Diisopropylammonium chloride: a ferroelectric organic salt with a high phase transition temperature and practical utilization level of spontaneous polarization.

A simple organic salt, diisopropylammonium chloride, shows the highest ferroelectric phase transition temperature among molecule-based ferroelectrics with a large spontaneous polarization, making it a candidate for practical technological applications.

4-(cyanomethyl)anilinium perchlorate: a new displacive-type molecular ferroelectric.

A new organic ferroelectric compound, 4-(cyanomethyl)anilinium perchlorate, proceeds a second-order phase transition from a paraelectric phase (P2(1)/m) to a ferroelectric phase (P2(1)) at 184 K. A perfect ferroelectric hysteresis loop was observed even at 10 KHz. It is the first example of a molecule-based organic ferroelectric whose polarization can be switched at such a high frequency. The temperature dependent second harmonic generation effect shows that the second-order nonlinear coefficient is nearly zero above T(c) and proportional to the spontaneous polarization below T(c), suggesting the occurrence of symmetry breaking, in good agreement with crystal structural determination. The origin of ferroelectricity was ascribed to the displacements of -NH(3)(+) cations and ClO(4)(-) anions from the symmetric positions including a small part of the order-disorder behaviors of the ClO(4)(-) anions.

Supramolecular bola-like ferroelectric: 4-methoxyanilinium tetrafluoroborate-18-crown-6.

Molecular motion is one of the structural foundations for the development of functional molecular materials such as artificial motors and molecular ferroelectrics. Herein, we show that pendulum-like motion of the terminal group of a molecule causes a ferroelectric phase transition. Complex 4-methoxyanilinium tetrafluoroborate-18-crown-6 ([C(7)H(10)NO(18-crown-6)](+)[BF(4)](-), 1) shows a second-order ferroelectric phase transition at 127 K, together with an abrupt dielectric anomaly, Debye-type relaxation behavior, and the symmetry breaking confirmed by temperature dependence of second harmonic generation effect. The origin of the polarization is due to the order-disorder transition of the pendulum-like motions of the terminal para-methyl group of the 4-methoxyanilinium guest cation; that is, the freezing of pendulum motion at low temperature forces significant orientational motions of the guest molecules and thus induces the formation of the ferroelectric phase. The supramolecular bola-like ferroelectric is distinct from the precedent ferroelectrics and will open a new avenue for the design of polar functional materials.

Discovery of new ferroelectrics: [H2dbco]2 x [Cl3] x [CuCl3(H2O)2] x H2O (dbco = 1,4-Diaza-bicyclo[2.2.2]octane).

Compound [H(2)dbco](2) x [Cl(3)] x [CuCl(3)(H(2)O)(2)] x H(2)O undergoes a sharp dielectric anomaly and a paraelectric-to-ferroelectric phase transition at approximately -23 degrees C with a spontaneous polarization of 1.04 microC cm(-2), being the first molecular metal coordination compound ferroelectrics with a large dielectric response involving a 2 orders of magnitude enhancement and distinct Curie phase transition point. This work has proved an effective way for exploration of new ferroelectrics based on a five-coordinated divalent metal through the combination of crystal engineering and Landau phase transition theory.

4-Methyl-anilinium tetra-fluoro-borate 18-crown-6 clathrate.

In the title compound, C(7)H(10)N(+)·BF(4) (-)·C(12)H(24)O(6), the proton-ated 4-methyl-anilinium cation inter-acts with 18-crown-6 forming a rotator-stator structure, (C(6)H(4)CH(3)NH(3) (+))(18-crown-6), through three bifurcated N-H⋯(O,O) hydrogen bonds between the ammonium groups of the cations (-NH(3)) and the O atoms of the crown ether mol-ecule. The BF(4) (-) anions, the methyl group and the protonated -NH(3) groups of the 4-methylanilinium lie on a dual axis of rotation. The 18-crown-6 unit is perpendicular to the dual axis of rotation and the mirror plane which contains the dual axis of rotation. The benzene ring of 4-methylanilinium is perpendicular to the mirror plane and parallel to the dual axis.

4-Fluoro-anilinium tetra-chloridoferrate(III) 18-crown-6 clathrate.

The reaction of 4-fluoro-aniline hydro-chloride, 18-crown-6 and ferric chloride in methano-lic solution yields the title compound, (C(6)H(7)FN)[FeCl(4)]·C(12)H(24)O(6), which has an unusual supramolecular structure. N-H⋯O hydrogen-bonding inter-actions between the NH(3) (+) substituents of the 4-fluoro-anilinium cations and the O atoms of the crown ether mol-ecules result in a rotator-stator-like structure.

Dimethyl-ammonium perchlorate 18-crown-6 monohydrate clathrate.

The reaction of dimethyl-amine, 18-crown-6, and perchloric acid in methanol yields the title compound, C(2)H(8)N(+)·ClO(4) (-)·C(12)H(24)O(6)·H(2)O. The dimethyl-ammonium cation and the water mol-ecule inter-act with the 18-crown-6 unit: N-H⋯O hydrogen bonds are formed between the ammonium NH(2) (+) group and four O atoms of the crown ether, while the water mol-ecule on the other side of 18-crown-6 ring forms O-H⋯O hydrogen bonds with two other O atoms of the crown ether. All conventional donors and acceptors in the cations are thus engaged in hydrogen bonding. The ClO(4) (-) anion is disordered over two sites, and occupancies for the disordered O atoms were fixed at 0.5. In the crystal, the cations and anions are arranged in alternating layers.

2,2'-Bis(all-yloxy)-1,1'-binaphth-yl.

The complete mol-ecule of the title compound, C(26)H(22)O(2), is generated by a crystallographic twofold rotation axis. The dihedral angle between the planes of the two symmetry-related naphthalene ring systems is 69.05 (4)°, while that between the naphthalene ring system and the allyl plane is 13.7 (2)°. No hydrogen bonds or aromatic π-π stacking inter-actions are observed.