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High purity spherical β-Si3N4 particles were synthesized via an efficient carbothermal reduction–nitridation strategy by precise regulation. The results showed that nano-sized reactants with an appropriate ratio was significant for acquiring Si3N4 granules with pure β phase. c/a,b-axis length ratio of the β-Si3N4 particles could be adjusted by using various additives. Fine spherical β-Si3N4 particles can only be obtained with the help of CaO additive by L-S mechanism. Moreover, variations of underlying reaction mechanisms when changing the raw materials were comprehensively revealed. Owing to the high purity and fine spherical morphology, as-obtained β-Si3N4 powders are promising fillers for preparing resin-based composites with high thermal conductivities.

Joint inversion based on a correlation constraint utilizes a linear correlation function as a structural constraint. The linear correlation function contains a denominator, which may result in a singularity as the objective function is optimized, leading to an unstable inversion calculation. To improve the robustness of this calculation, this paper proposes a new method in which a sinusoidal correlation function is employed as the structural constraint for joint inversion instead of the conventional linear correlation function. This structural constraint does not contain a denominator, thereby preventing a singularity. Compared with the joint inversion method based on a cross-gradient constraint, the joint inversion method based on a sinusoidal correlation constraint exhibits good performance. An application to actual data demonstrates that this method can process real data.

To investigate the diagnostic value of contrast-enhanced three-dimensional (3D) T2-weighted turbo spin-echo SPACE (T2-SPACE) sequence in LNRC.A total of 90 surgically confirmed LNRC patients with 165 explored nerve roots were enrolled in this study. Diagnostic values were quantified using sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy. The consistency between 2D MRI and 3D T2-SPACE MRI was quantified using kappa test. The compression of specific branch in nerve root was evaluated on 2D MRI, 3D T2-SPACE MRI, and surgical findings. The pedicle height, vertebral body height (VH), proximal tilting angle of nerve root (PTA) were measured on MR images.The sensitivity, specificity, PPV, NPV, and accuracy by 2D MRI were 78.3%, 72.7%, 94.9%, 34.0%, and 77.6%, respectively. For 3D T2-SPACE MRI imaging, the sensitivity, specificity, PPV, NPV, and accuracy were 91.6%, 86.4%, 97.8%, 61.3%, and 90.9%, respectively. 2D MRI and 3D T2-SPACE MRI for detection of intra-foramen and extra-foramen nerve compression showed poor homogeneity (Kappa = 0.333, Kappa = 0.276, respectively). Smaller VHs and larger PTAs could be indicators for the diagnosis of foraminal nerve root compression.3D T2-SPACE MRI had a higher sensitivity, specificity, PPV, NPV, and accuracy than 2D MRI for detecting LNRC. The 3D T2-SPACE scan could be a good substitute to routine 2D MRI in LNRC diagnosis, especially for foraminal nerve root compression patients.III.

Rare earth doped perovskite has become one of the most attractive multifunctional materials benefiting from the unique ferro-/piezoelectric, photocatalytic and photoluminescence properties. In this contribution, a series of Er3+ doped KNbO3 nanocrystals with distinctive morphologies, i.e., nanocubes, nanocuboids, and quasi-nanospheres, were prepared via a facile molten salt synthesis method. Furthermore, using the as-synthesized nanocrystals, the Er3+ doped KNbO3 ceramics with homogeneous nanograins were obtained. The growth mechanism of the nanocrystals with different morphologies and sintering process of the nanoceramics were rationally proposed, respectively. It was demonstrated that the morphology of the nanocrystals could be controlled by adjusting the doping amount of Er3+ and the structure of the as-sintered nanoceramics strongly depends on the morphology of the pristine nanocrystals. Impressively, the Er3+-KNbO3 nanocrystals and nanoceramics exhibited excellent up-conversion photoluminescence (UC PL) properties. This work may pave a new way to the structure-controlled synthesis of rare earth doped perovskite oxides and related nanoceramics, which show large potential in applications of novel multifunctional devices.

Perovskite oxides have attracted much attention owing to their excellent physical properties, such as piezoelectricity, ferroelectricity, and ferromagnetism. Moreover, these properties can be strongly affected and regulated by the doping strategy. In this work, Er3+ doped single crystal KNbO3 nanosheets were successfully synthesized via a solvothermal method. XRD analysis indicated that Er3+ firstly substituted into the B site (Nb5+) and then A site (K+) in the ABO3 perovskite structure with the further increasing content of Er3+. The orthorhombic structure of the pure KNbO3 and Er3+ doped KNbO3 was proved in terms of the Raman spectra. The SEM observation demonstrated that the size of the as-obtained nanosheets was about 70 nm in thickness and 3 μm in diameter. The single crystal structure state of the as-obtained products was confirmed by HRTEM. Furthermore, the growth mechanism of Er3+ doped KNbO3 nanosheets was rationally elaborated and proposed. The as-obtained Er3+ doped KNbO3 nanosheets exhibited excellent up-conversion (UC) photoluminescence (PL) properties with a strong green emission and a weak red emission. The maximum emission intensity of the UC PL spectrum was achieved with 0.4 mol% of Er3+ doped. To conclude, the as-synthesized Er3+ doped KNbO3 nanosheets could be a potential candidate for the development of multifunctional devices, by introducing PL properties to piezoelectric KNbO3 materials.

The Er-doped perovskite single-crystal NaNbO3 nanorods with a series of doping content (0–1 wt%) were successfully synthesized by hydrothermal method. The XRD and Raman analyses indicated that the Er3+ ion firstly entered into the B site (Nb5+) in the ABO3 perovskite structure and then the A site (Na+) with a further increase of Er-doping content. High-resolution transmission electron microscopy (HRTEM) was employed to demonstrate the single-crystal features of NaNbO3 nanorods. The as-synthesized Er-doped NaNbO3 nanorods exhibited excellent up-conversion (UC) photoluminescence (PL) behavior. The strong green emission and the weak red emission of Er3+ were observed in the UC PL spectra. The maximum emission intensity of the UC PL spectrum was achieved in NaNbO3 nanorods with 0.5 wt% of Er3+ doped. Furthermore, the UC PL spectra obtained under different laser input powers confirmed that two photons contributed to the observed up-conversion luminescence properties. Owing to these luminescent merits, the as-synthesized Er-doped single-crystal perovskite NaNbO3 nanorods exhibit potential application in novel multifunctional devices.

To establish single- and double-transfected transgenic cells stably expressing hMATE1, hMATE1 cDNA was cloned by RT-PCR from human cryopreserved kidney tissue, and subcloned into pcDNA3.1(+) plasmid by virtue of both HindIII and Kpn I restriction enzyme sites. Subsequently, the recombined pcDNA3.1(+)- hMATE1 plasmid was transfected into MDCK, MDCK-hOCT1 or MDCK-hOCT2 cells using Lipofectamine 2000 Reagent. After a 14-day-cultivation with hygromycin B at the concentration of 400 µg · mL(-1), all clones were screened with DAPI and MPP+ as substrates to identify the best candidate. The mRNA content of hMATE1, the cellular accumulation of metformin with or without cimetidine as inhibitor, or transportation of cimetidine was further valuated. The results showed that all of the three cell models over expressed hMATE1 mRNA. The cellular accumulation of metformin in MDCK-hMATE1 was 17.6 folds of the control cell, which was significantly inhibited by 100 µmol · L(-1) cimetidine. The transcellular transport parameter net efflux ratios of cimetidine across MDCK-hOCT1/hMATE1 and MDCK-hOCT2/hMATE1 monolayer were 17.5 and 3.65, respectively. In conclusion, cell models with good hMATE1 function have been established successfully, which can be applied to study the drug transport or drug-drug interaction involving hMATE1 alone or together with hOCT1/2 in vitro.

Tetrahydropalmatine (THP), with one chiral center, is an alkaloid that possesses analgesic and many other pharmacological actives. The aim of the present study is to investigate stereoselective metabolism of THP enantiomers in human liver microsomes (HLM) and elucidate which cytochrome P450 (CYP) isoforms contribute to the stereoselective metabolism in HLM. Additionally, the inhibitions of THP enantiomers on activity of CYP enzymes are also investigated. The results demonstrated that (+)-THP was preferentially metabolized by HLM. Ketoconazole (inhibitor of CYP3A4/5) inhibited metabolism of (-)-THP or (+)-THP at same degree, whereas the inhibition of fluvoxamine (inhibitor of CYP1A2) on metabolism of (+)-THP was greater than that of (-)-THP; moreover, the metabolic rate of (+)-THP was 5.3-fold of (-)-THP in recombinant human CYP1A2. Meanwhile, THP enantiomers did not show obvious inhibitory effect on the activity of various CYP isoforms (CYP1A2, 2A6, 2C8, 2C9, 2C19, 2E1, and 3A4/5), whereas (-)-THP, but not (+)-THP, significantly inhibited the activity of CYP2D6 with the Ki value of 6.42 ± 0.38 μM. The results suggested that THP enantiomers were predominantly metabolized by CYP3A4/5 and CYP1A2 in HLM, and (+)-THP was preferentially metabolized by CYP1A2, whereas CYP3A4/5 contributed equally to metabolism of (-)-THP or (+)-THP. Besides, the inhibition of CYP2D6 by (-)-THP may cause drug-drug interaction, which should be considered.

Tetrahydropalmatine (THP), with one chiral center, is an active alkaloid ingredient in Rhizoma Corydalis. The aim of the present paper is to study whether THP enantiomers are metabolized stereoselectively in rat, mouse, dog, and monkey liver microsomes, and then, to elucidate which Cytochrome P450 (CYP) isoforms are predominately responsible for the stereoselective metabolism of THP enantiomers in rat liver microsomes (RLM). The results demonstrated that (+)-THP was preferentially metabolized by liver microsomes from rats, mice, dogs, and monkeys, and the intrinsic clearance (Cl(int)) ratios of (+)-THP to (-)-THP were 2.66, 2.85, 4.24, and 1.67, respectively. Compared with the metabolism in untreated RLM, the metabolism of (-)-THP and (+)-THP was significantly increased in dexamethasone (Dex)-induced and β-naphthoflavone (β-NF)-induced RLM; meanwhile, the Cl(int) ratios of (+)-THP to (-)-THP in Dex-induced and β-NF-induced RLM were 5.74 and 0.81, respectively. Ketoconazole had stronger inhibitory effect on (+)-THP than (-)-THP, whereas fluvoxamine had stronger effect on (-)-THP in untreated and Dex-induced or β-NF-induced RLM. The results suggested that THP enantiomers were predominately metabolized by CYP3A1/2 and CYP1A2 in RLM, and CYP3A1/2 preferred to metabolize (+)-THP, whereas CYP1A2 preferred (-)-THP.

To investigate the difference in absorptive of tetrahydropalmatine (THP) and l-tetrahydropalmatine (l-THP) in rat intestine as well as the mechanism of the absorption of THP, in situ single pass perfusion model was used and the concentration of THP in perfusate was determined by HPLC. The absorption rate constant (k(a)) and effective permeability values (P(eff)) of THP had no significant difference (P0.05) at concentration of 8, 16 and 32 microg x mL(-1) in perfusion or in four different regions of intestine of rat (duodenum, jejunum, ileum, colon). The absorption of l-THP and THP in jejunum had significant difference (P0.05). The k(a) and P(eff) of THP increased obviously when verapamil was co-perfused with THP, while those of l-THP were not influenced by verapamil. The absorption of THP in intestine showed the passive diffusion process, and without a special absorption region. The stereoselective absorption difference may result from stereoselective combination of P-glycoprotein with d-THP.