Novel co-crystal of 3-methylcinnamic acid with berberine (1:1): synthesis, characterization, and intestinal absorption property.

OBJECTIVE: To synthesis a novel 'Pharmaceutical Cocrystal' of berberine (BBR) with coformer 3-methylcinnamic acid (3MCA) for increasing its solubility and intestinal absorption property. SIGNIFICANCE: BBR-HCl has poor liposolubility, difficulty in penetrating the cell membrane and absorption in the gastrointestinal tract, low bioavailability, and limited clinical application. A new cocrystal is formed by the interaction between 3-MCA and BBR through molecular interaction, which improves the physicochemical properties, intestinal absorption property, and hygroscopicity. METHODS: The solvent evaporation method was used to synthesize BCR-3MCA cocrystal. The physicochemical properties of the crystals were confirmed by different spectral techniques, i.e. by X-ray diffraction (PXRD, SXRD), thermogravimetry and differential thermal analysis (DSC, TGA), and scanning electron microscopy (SEM). Hygroscopicity of the cocrystal was evaluated by dynamic water vapor sorption (DVS). The intestinal absorption property was evaluated by the Ussing chamber system. RESULTS: BBR and 3MCA can be directly self-assembled into uniform co-crystal by hydrogen bonds and π-π stacking interactions. Compared with BBR-HCl, the solubility of BBR-3MCA cocrystal in polar solvents of water, methanol, ethanol, and isopropanol increased by 13.9, 1.5, 4.7, and 15.8 times, respectively. The apparent absorption and the absorption rate constants were increased by 7.7 and 5.6 times, respectively. Surprisingly, BBR-3MCA co-crystal almost had no hygroscopicity. CONCLUSION: The absolute molecular structure of the co-crystal was further confirmed by single crystal X-ray diffraction. The hydrogen bonds drove the formation of X-like one-dimensional unit. Compared to the BBR-HCl, BBR-3MCA cocrystal displayed superior dissolution and solubility performance, improved physical-chemical properties and significantly improved intestinal absorption.

Electro-optic modulator based on a photonic crystal slab with electro-optic polymer cladding.

A type of modulator based on a shallow-etched photonic crystal (PC) slab of silicon-on-insulator material with electro-optic (EO) polymer cladding is designed and investigated. The transmission spectra of the PC slab with the EO polymer are calculated using a finite-difference time-domain method. The band structure and the field distribution of the guided mode resonance are calculated and analyzed. The modulation voltage and bandwidth of the hybrid modulator are simulated. It is shown that flexible designs of low-voltage modulation (0.2 V) or high-bandwidth modulation (62 GHz) can be obtained with the hybrid modulator.

Bonding III-V material to SOI with transparent and conductive ZnO film at low temperature.

A procedure of bonding III-V material to SOI at low temperature using conductive and transparent adhesive ZnO as intermediate layer is demonstrated. Bonding layer thickness of less than 100 nm was achieved in our experiment that guaranteed good light coupling efficiency between III-V and silicon. This bonding method showed good bonding strength with shear stress of 80 N/cm(2). The lowest resistance of the bonded samples was 48.9 Ω and the transmittance of the spin-coated ZnO layer was above 99%. This procedure is applicable for fabricating hybrid III-V/Si lasers.

Influence of Long-Period Stacked Ordered Phases on Inductive Impedance of Mg-Gd-Y-Zn-Zr-Ag Alloys.

In this paper, the influence of long-period stacked ordered (LPSO) phases on the electrochemical impedance spectroscopy (EIS) of a Mg-Gd-Y-Zn-Zr-Ag alloy in 0.9 wt.% NaCl was investigated. The Mg-6Gd-3Y-1Zn-0.5Zr-0.3Ag (wt.%) alloy samples with and without LPSO phases in the grain interior (HOMO and LPSO, respectively) were prepared using different heat treatments. The EIS results showed that both the HOMO and LPSO samples' Nyquist diagrams contained two inductive loops. However, in the Nyquist plots of the LPSO samples, the inductive loops at 1.71-0.67 Hz appeared in the first quadrant rather than the fourth quadrant. Analysis of the fitting parameters illustrated that the abnormal shape of the inductive loops is related to greater values of the surface film capacitance Cf and double layer capacitance Cdl in the LPSO samples. Further investigations through corrosion morphology observation indicated that the greater values of Cf and Cdl in the LPSO samples resulted from the existence of intragranular LPSO phases that created more film-free areas. The above results show that a better understanding of the relationship between the inductive impedance and corrosion morphology of a Mg-6Gd-3Y-1Zn-0.5Zr-0.3Ag alloy in 0.9 wt.% NaCl solution was attained.

HS-Vectors: Heart Sound Embeddings for Abnormal Heart Sound Detection Based on Time-Compressed and Frequency-Expanded TDNN With Dynamic Mask Encoder.

In recent years, auxiliary diagnosis technology for cardiovascular disease based on abnormal heart sound detection has become a research hotspot. Heart sound signals are promising in the preliminary diagnosis of cardiovascular diseases. Previous studies have focused on capturing the local characteristics of heart sounds. In this paper, we investigate a method for mapping heart sound signals with complex patterns to fixed-length feature embedding called HS-Vectors for abnormal heart sound detection. To get the full embedding of the complex heart sound, HS-Vectors are obtained through the Time-Compressed and Frequency-Expanded Time-Delay Neural Network(TCFE-TDNN) and the Dynamic Masked-Attention (DMA) module. HS-Vectors extract and utilize the global and critical heart sound characteristics by masking out irreverent information. Based on the TCFE-TDNN module, the heart sound signal within a certain time is projected into fixed-length embedding. Then, with a learnable mask attention matrix, DMA stats pooling aggregates multi-scale hidden features from different TCFE-TDNN layers and masks out irrelevant frame-level features. Experimental evaluations are performed on a 10-fold cross-validation task using the 2016 PhysioNet/CinC Challenge dataset and the new publicly available pediatric heart sound dataset we collected. Experimental results demonstrate that the proposed method excels the state-of-the-art models in abnormality detection.

Field-tuned quantum effects in a triangular-lattice Ising magnet.

We report thermodynamic and neutron scattering measurements of the triangular-lattice quantum Ising magnet TmMgGaO4 in longitudinal magnetic fields. Our experiments reveal a quasi-plateau state induced by quantum fluctuations. This state exhibits an unconventional non-monotonic field and temperature dependence of the magnetic order and excitation gap. In the high field regime where the quantum fluctuations are largely suppressed, we observed a disordered state with coherent magnon-like excitations despite the suppression of the spin excitation intensity. Through detailed semi-classical calculations, we are able to understand these behaviors quantitatively from the subtle competition between quantum fluctuations and frustrated Ising interactions.

Cluster radioactivity of neutron-deficient nuclei in trans-tin region.

The possibility of cluster radioactivity (CR) of the neutron-deficient nuclei in the trans-tin region is explored by using the effective liquid drop model (ELDM), generalized liquid drop model (GLDM), and several sets of analytic formulas. It is found that the minimal half-lives are at Nd = 50 (Nd is the neutron number of the daughter nucleus) for the same kind cluster emission because of the Q value (released energy) shell effect at Nd = 50. Meanwhile, it is shown that the half-lives of α-like (Ae = 4n, Ze = Ne. Ze and Ne are the charge number and neutron number of the emitted cluster, respectively.) cluster emissions leading to the isotopes with Zd = 50 (Zd is the proton number of the daughter nucleus) are easier to measure than those of non-α-like (Ae = 4n + 2) cases due to the large Q values in α-like cluster emission processes. Finally, some α-like CR half-lives of the Nd = 50 nuclei and their neighbours are predicted, which are useful for searching for the new CR in future experiments.

Enhanced Mechanical and Corrosion Performance by Forming Micro Shear Bands in Cold Forged Mg-Gd-Y-Zr Alloy.

Forging at room temperature was applied on the per-extruded Mg-Gd-Y-Zr alloy to investigate the effect of cold forging on the microstructure, mechanical properties and corrosion resistance of the alloy. Abundant micro shear bands with misorientations of 2-15° were generated in the as forged alloys. Tremendous enhancement in tensile yield strength was achieved after forging. With a quantitative investigation, micro band boundaries were considered to provide a great contribution to the reinforcement. The ultrafine structure resulting from the formation of micro shear bands led to increased corrosion resistance of the alloy.

Effects of T5 Treatment on Microstructure and Mechanical Properties at Elevated Temperature of AZ80-Ag Alloy.

Effects of T5 treatment on microstructure and mechanical properties at elevated temperature of hot-ring-rolled (HRRed) AZ80-Ag magnesium alloy were systematically investigated. Results show that, after aging at 175 °C for 36 h, discontinuous and continuous precipitates form inside grains, with the former one taking up a volume fraction of ~64.9%. T5 treatment improves the tensile strength at ambient temperature of the alloy but weakens its tensile strength and creep resistance at elevated temperatures (120-175 °C), indicating opposite effects of T5 on mechanical properties at ambient and elevated temperatures. During creep at 120-175 °C and under 70-90 MPa, the dynamic precipitation process in HRRed specimen is accelerated with increasing temperature. At 150-175 °C massive nucleation and growth of dynamic discontinuous precipitates could result in an atypical primary creep stage, consisting of deceleration and acceleration creep stages, which is reported in wrought Mg-Al-based alloy for the first time. Such primary creep stage can be eliminated by T5 treatment. Besides, diffusion-controlled dislocation creep is the dominant creep mechanism for both HRRed and T5 specimens.

Mechanical behaviour of cp-magnesium with duplex hydroxyapatite and PEO coatings.

Hydroxyapatite-magnesia coatings were formed on cp-magnesium by plasma electrolytic oxidation (PEO) followed by cathodic electrodeposition (CED). The static tensile and cyclic fatigue performance of the coated samples were investigated. The cracking behaviour of the coatings during the tensile tests was studied by fracture analysis. The effects of the surface treatment on the fatigue performance of the magnesium substrate were addressed. Tensile strength of cp-Mg was not significantly affected, whereas the fatigue performance was improved by the PEO+CED coatings in the low-cycle region, possibly due to compressive residual stress induced to the metal substrate by the surface treatment. However, reduced fatigue strength was observed in the high-cycle region, which might be attributed to the defects at the coating/substrate interface produced during the surface modification. The in vitro corrosion reduced the fatigue strength in both the low- and high-cycle regions. Finally, the applicability of surface engineered magnesium for biomedical applications was demonstrated from the mechanical standpoint.