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High-performance liquid chromatography (HPLC) is one of the most widely used separations and analysis methods, which has become an indispensable part of the separation and detection of mixtures, qualitative and quantitative analysis and other scientific research and social production fields. Because of the decisive effect of the chromatographic column on analysis and separation, it has become the core of research in the chromatographic system. In the past decades, the research and development of new chromatographic column stationary phase have been highly concerned. Monodisperse polymer microsphere, because of its special large pore structure, has good permeability and high specific surface area, which can be used as special materials in various fields, such as adsorption materials in the separation process, HPLC column packing, catalyst carrier, preparation template of nanomaterials and nuclear fusion targeting materials. When it is used in HPLC, because of the good permeability of microspheres, it can effectively improve the separation efficiency and performance. In this article, based on the previous work, a number of new polymer microspheres were prepared, and the prepared microspheres were used for the separation and detection of HPLC, and their physical and chemical properties were studied. [ABSTRACT FROM AUTHOR]

Magnetic Core-shell nanoparticles coated with an adenine-imprinted polymer layer were successfully synthesized. The morphology of the nanoparticles was characterized by transmission electron microscopy (TEM). The nanoparticles have a definite core-shell structure and an imprinted polymer layer. The adsorption, recognition and reusability of the molecularly imprinted nanoparticles were analyzed by static/dynamic adsorption, competitive adsorption and reproducibility experiment. The magnetic molecularly imprinted nanoparticles exhibit fast adsorption, high adsorption capacity, strong specificity and satisfactory recovery. [ABSTRACT FROM AUTHOR]

Polymer microparticles with size-controlled single pore was synthesized successfully using seeded emulsion polymerization. The pore size can be changed with relevant parameters. A scanning electron microscope(SEM) was used to characterize their pore size and morphology. Through measurement and calculation of SEM images, the change rules of pore size with the amount of monomer and porogen were taken. [ABSTRACT FROM AUTHOR]

The reaction microscopic mechanism of mixed aqueous solutions of nitrobenzene and hydrogen peroxide under different conditions was studied by the laser flash photolysis technique (266 nm). The main characteristic peaks in these transient absorption spectra were attributed and the build-up/decay trends of several transient species were investigated. The transient absorption peaks of 285 nm and 305 nm were attributed to when nitrobenzene aqueous solutions were irradiated by 266 nm UV light and the decay rate constant was k 285 nm = 1.22 × 104 s−1 and k 305 nm = 1.05 × 104 s−1 in the presence of N2. k 285 nm and k 305 nm increased to 1.32 × 104 s−1 and 2.05 × 104 s−1, respectively, in the presence of O2. OH radical can be produced through the 266 nm laser flash photolysis of hydrogen peroxide in aqueous solutions. The rate constant of the reaction between OH radical and nitrobenzene was measured to be (3.6–6.0) × 109 (L · mol−1 · s−1). The intermediate of the C6H5NO2-OH adduct can undergo secondary self-decay with a reaction rate of 2k/ϵl = 1.82 × 106 s−1. The C6H5NO2-OH adduct is able to react with O2 to form C6H5NO2-OHO2 with a rate constant of (6.6 ± 0.56) × 107 (L · mol−1 · s−1). [ABSTRACT FROM PUBLISHER]

Four novel taxoid analogs were conversionally synthesized from the C19-diterpenoid alkaloid deltaline, and their cytotoxic activities were evaluated against a small panel of cancer cell lines. [ABSTRACT FROM AUTHOR]

The regioselective demethylations of two C19-diterpenoid alkaloids, 2 and 3, have been achieved with HBr-HOAc, trimethylsilyl iodide, or BBr3. It was observed that HBr-HOAc is an optimal demethylating agent for these two C19-diterpenoid alkaloids because it could provide different O-demethylation products by using different reaction temperature and reaction time. Especially, 1-O-methyl group in 2 and 3, one of the most difficult ones to be demethylated, could be removed by the treatment with HBr-HOAc at an elevated temperature and a prolonged reaction time. [ABSTRACT FROM AUTHOR]

Manifold learning is a fast growing area of research recently. The main purpose of manifold learning is to search for intrinsic variables underlying high-dimensional inputs which lie on or are close to a low-dimensional manifold. Different from current theoretical works and applications of manifold learning approaches, in our work manifold learning framework is transferred to tracking feature extraction for the first time. The contributions of this article include three aspects. Firstly, in this article, we focus on tracking feature extraction for dynamic visual tracking on dynamic systems. The feature extracted in this article is based on manifold learning framework and is particular for dynamic tracking purpose. It can be directly applied to system control of dynamic systems. This is different from most traditional tracking features which are used for recognition and detection. Secondly, the proposed tracking feature extraction method has been successfully applied to three different dynamic systems: dynamic robot system, intelligent vehicle system and aircraft visual navigation system. Thirdly, experimental results have proven the validity of the tracking method based on manifold learning framework. Particularly, in the tracking experiments the vision system is dynamic. The tracking method is also compared with the well-known mean-shift tracking method, and tracking results have shown that our method outperforms the latter. [ABSTRACT FROM AUTHOR]

The conversional synthesis of taxoids by the BAC sequence from the C19-diterpenoid alkaloids, 14-acetyltalatisamine (1), yunaconitine (12), and 14-acetylchasmanine (19), was designed and explored. Two aconane-type diterpenes 17 and 28, the advanced intermediates for our conversional synthesis, were synthesized. The key steps include the rupture of the C(7)-C(17) bond, the formation of imine, and the denitrogenation. [ABSTRACT FROM AUTHOR]

Three new C19-diterpenoid alkaloids, umbrosumines A-C (1-3), and 11 known compounds (4-14) were isolated from the roots of Delphinium umbrosum. Their structures were elucidated on the basis of the spectroscopic data interpretation. [ABSTRACT FROM AUTHOR]

In the title study, the synthesis of the vital intermediate C-nor-aconanone (3) from 4 was completed through 11 steps, mainly including semipinacol rearrangement, formation of the imines by the treatment of 10 or 20 with NBS, the cleavage of N-C(19) bonds in 11 or 21 by treatment with m-CPBA and subsequently with LTA, as well as the rupture of the N-C(17) bonds in 22 by a modified Nef reaction (NaH/t-BuOH → KMnO4/H2O). One-pot procedure was successfully developed starting from 11 or 21 to afford the N,19-seco-C-nor product 15 or 22, respectively, in reasonably good yields. [ABSTRACT FROM AUTHOR]

Purpose: To search for markers of Behçet disease (BD) activity, we measured CXCR1 and CXCR2 levels on the circulating leukocytes of patients suffering from ocular BD. Methods: Peripheral blood leukocytes were harvested from healthy volunteers (n = 16) and ocular BD patients (n = 35). The patients consisted of 15 individuals in relapsing phase (6 with prednisolone treatment) and 20 individuals in remission phase (9 with prednisolone treatment). Expression of CXC chemokine receptors (CXCRs) on leukocytes (including lymphocytes, monocytes, neutrophils) was measured using flow cytometry. Results: Without prednisolone treatment, CXCR2 expression (on both total leukocytes and neutrophils) in relapsing phase was significantly higher than in remission-phase patients or normal individuals. By contrast, no significant difference was detected in the expression of CXCR1 between any of the groups. Importantly, low-dose prednisolone therapy reduced CXCR2 expression on neutrophils. Conclusions: CXCR2 has a potential role in promoting uveitis during ocular attack and might also be a useful marker for disease activity. [ABSTRACT FROM AUTHOR]

Two new C 19 -diterpenoid alkaloids, kongboentine A ( 1 ) and kongboentine B ( 3 ), were isolated from the roots of Aconitum kongboense Lauener and their structures were elucidated by spectral data. [ABSTRACT FROM AUTHOR]

Following the report on the synthesis of the 7,17-seco compounds [Wang, F.P., Yang, J.S., Chen, Q.H., Yu, L. and Li, B.G. (2000), Chem. Pharm. Bull. 48, 1912-1916], further studies on the reaction optimization for cleavage of the C(7),C(17) bond led to the 7,17-seco norditerpenoid alkaloids (e.g. 4, 9) in nearly 90% yield. [ABSTRACT FROM AUTHOR]

AbstractObjectiveMethodsResultsConclusionThis study assesses the efficacy of rituximab in the treatment of neuromyelitis optica spectrum disorders (NMOSD).The study initially included 40 patients with NMOSD diagnosed, after excluding patients who did not meet the complete inclusion criteria. Patients in the conventional group received routine clinical treatment, while patients in the study group received additional treatment with rituximab on the basis of the conventional treatment. Baseline data and clinically relevant indicators were collected for all patients, and the efficacy was compared between the two groups.Baseline data were comparable between the two groups (p > 0.05). The EDSS scores after clinical treatment in the study group were lower than those in the conventional group, and the difference in EDSS scores before and after treatment was higher than that in the conventional group (p < 0.05). The difference in visual acuity correction before and after treatment was not significant between the two groups (p > 0.05). Laboratory indicators in the study group after clinical treatment were superior to those in the conventional group (all p < 0.05). The recurrence rate after clinical treatment in the study group was significantly lower than that in the conventional group (p < 0.05). Adverse reactions after clinical treatment in the study group were less than those in the conventional group (p < 0.05).This study found that rituximab demonstrated significant efficacy in the acute attacks and recurrence prevention of NMOSD, emphasizing its relatively good safety and tolerability. It highlights the potential of rituximab in treating NMOSD and provides valuable insights for future disease management. [ABSTRACT FROM AUTHOR]

In this paper, the complete mitochondrial genome ofChlorophthalmus nigromarginatushas been determined. The mitochondrial genome (17,663 bp) had the canonical mitochondrial gene content and arrangement, including 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and 2 non-coding regions. The overall base composition of the heavy-strand is 25.66% A, 25.71% T, 17.82% G, and 30.81% C, with an AT content of 51.37%. It shared 86.6% identities withChlorophthalmus agassizi. The phylogenetic analyses indicated the close relationship between the mitochondrial genome we presented and other species in order Aulopiformes. [ABSTRACT FROM AUTHOR]

The major aim of this study is to elucidate the hypocholesterolemic mechanism exerted by rice protein (RP) in adult rats under cholesterol-enriched dietary condition. Compared with casein, the cholesterol levels in plasma and the liver were significantly reduced by RP, accompanying significant inhibition of cholesterol absorption. RP increased the activity and mRNA level of cholesterol 7α-hydroxylase, whereas acyl-CoA:cholesterol acyltransferase activity and gene expression were significantly depressed with consumption of RP. Neither the activity nor gene expression of 3-hydroxy-3-methylglutaryl coenzyme A reductase of RP differed from that of casein. The gene expression of the peroxisome proliferator-activated receptor α and liver X receptor α were significantly activated by consumption of RP. RP did not modify the mRNA level of sterol regulatory element-binding protein-2 with respect to casein. These results suggest RP can induce a cholesterol-lowering effect through modifying cholesterol metabolism-related gene expression and enzyme activity in adult rats. [ABSTRACT FROM AUTHOR]

Objective: To investigate the efficacy of radiofrequency ablation (RFA) as a treatment option for primary hyperparathyroidism (pHPT) and risk factors for postablative eucalcemic parathyroid hormone elevation (ePTH). Methods: This retrospective study included 51 patients with pHPT who underwent RFA. The patients were divided into the ePTH and normal PTH groups, based on the serum intact parathyroid hormone (iPTH) level one month after ablation. Serum iPTH, calcium, and phosphorus levels, and the volume reduction rates (VRR) of the parathyroid glands were compared between the groups at each follow-up point. Risk factors for ePTH at one month after ablation were examined. Results: After RFA, one (2%) patient had persistent pHPT, and 50 (98%) patients were cured. The incidence rates of ePTH at 1, 3, 6, and 12 months were 48%, 30%, 20%, and 16%, respectively. Serum iPTH levels in the ePTH group were higher than those in the normal PTH group at each follow-up point (all p < 0.05), except 1 day after ablation (p > 0.05). Serum calcium and phosphorus levels, and the VRR of the glands were comparable in both groups at each follow-up point (all p > 0.05), except for calcium levels 3 days after RFA (p < 0.05). Baseline iPTH (odds ratio, 1.067; p ¼ 0.045) and calcium (odds ratio, 3.923; p ¼ 0.038) levels were independent risk factors for ePTH 1 month after RFA. Conclusions: RFA is safe and effective for the treatment of pHPT. Moreover, ePTH occurrence after RFA was associated with baseline iPTH and calcium levels and did not increase the risk of recurrent pHPT. [ABSTRACT FROM AUTHOR]

The O-acyl group at C-1 of two C19-diterpenoid alkaloids 2 and 5 was transferred to the secondary amine nitrogen to form amides 3 and 6 in the basic condition. This kind of O-to-N intramolecular acyl migration could be caused by the near distance between the nucleophilic nitrogen atom and the carbonyl group of the ester at C-1 in the C19-diterpenoid alkaloids, which is consistent with the conformation of rings A and E in the C19-diterpenoid alkaloids. [ABSTRACT FROM AUTHOR]

The first biomimetic conversion from the aconitine-type C19-diterpenoid alkaloids to the corresponding alkaloids of lactone-type C19-diterpenoid alkaloid has been achieved. Chasmanine was used as starting material with Baeyer–Villiger oxidation as a key reaction. It was also observed that the oxygenated group at C-16 did not change the relative migration tendencies of C-13 and C-9 during the oxidation. Meantime, a novel D-ring fragmented compound was obtained during the course of the present investigation. The plausible mechanism of the formation of this compound was also proposed. [ABSTRACT FROM AUTHOR]

Eighteen schizandrin A derivatives, possessing an acyl group at 7-OH and/or halogen(s) at C-4 and C-11, were designed and synthesized for evaluation of their in vitro ability to inhibit multidrug resistance (MDR). They exhibit weak ability to restore the intracellular Rhodamine 123 in human hepatocarcinoma MDR cell lines Bel7402 and HCT8 relative to the reference drug verapamil. [ABSTRACT FROM AUTHOR]

Treatment of some C19-diterpenoid alkaloids (3, 6, 10 and 12) with anhydrous DMSO at 100-170°C for 3-7 h led to the formation of the corresponding imines (4, 7/8, 11, 13/14) in 65-83% yield, respectively. This is a new simpler formation of the imines of the C19-diterpenoid alkaloids. [ABSTRACT FROM AUTHOR]

A new franchetine-type (leueandine 1 ) and two new lycoctonine-type [potanisines F ( 3 ) and G ( 5 )] C 19 -diterpenoid alkaloids have been isolated from the roots of Aconitum hemsleyanum var. leueanthus and Delphinium potaninii , respectively, and their structures were established on the basis of spectral data. [ABSTRACT FROM AUTHOR]

Many surveillance systems of infectious diseases are syndrome-based, capturing patients by clinical manifestation. Only a fraction of patients, mostly severe cases, undergo laboratory validation to identify the underlying pathogen. Motivated by the need to understand transmission dynamics and associate risk factors of enteroviruses causing the hand, foot, and mouth disease (HFMD) in China, we developed a Bayesian spatio-temporal modeling framework for surveillance data of infectious diseases with small validation sets. A novel approach was proposed to sample unobserved pathogen-specific patient counts over space and time and was compared to an existing sampling approach. The practical utility of this framework in identifying key parameters was assessed in simulations for a range of realistic sizes of the validation set. Several designs of sampling patients for laboratory validation were compared with and without aggregation of sparse validation data. The methodology was applied to the 2009 HFMD epidemic in southern China to evaluate transmissibility and the effects of climatic conditions for the leading pathogens of the disease, enterovirus 71, and Coxsackie A16. for this article are available online. [ABSTRACT FROM AUTHOR]

To design thermal fit parameters such as heating temperature and insertion force, it is generally necessary to conduct structural and thermal analyses, respectively. This study aims to build an integrated thermal assembly model to design the heating temperature and insertion force parameters simultaneously. A hierarchical multiple-kernel regression is proposed to map the two parameters and the thickness of the workpiece to the contact stress. Using the regression method, we can design the thermal fit parameters efficiently. The proposed model is validated experimentally based on two shaft-bearing assemblies. The results show that the model is capable of accurately predicting the contact stress in assembly. [ABSTRACT FROM AUTHOR]

Adenine molecular imprinted polymethacrylic acid (PMAA) was in situ prepared on the surface of silica (SiO2) microspheres, constituting a thin and rough molecular imprinted polymer (MIP) layer as characterized by SEM, TEM and FT-IR. Dynamic method and competitive adsorption experiments were used to investigate the adsorption kinetics, adsorption isotherms, selective recognition and adsorption reproducibility of MIP-PMAA/SiO2particles toward adenine. The results showed that the obtained particles have strong selective affinity, specific recognition and excellent reusability for adenine. MIP-PMAA/SiO2particles were further used as stationary phase for high performance liquid chromatography (HPLC) and separation of adenine from other nucleic bases was achieved successfully. [ABSTRACT FROM AUTHOR]

Carboxyl-La@C82 modified the gold electrode was applied to the detection of dopamine (DA). The electrochemical behavior of the modified electrode was examined using the cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods. Electrode surface morphology was characterized by scanning electronic microscopy (SEM). Compared with the bare electrode, the carboxyl-La@C82 modified electrode was more sensitive with a DA detection limit of 1.0 x 10-8 mol/L in the presence of uric acid (UA). In addition, the electrode was also applied to the detection of actual sample successfully. The good performance of the carboxyl-La@C82 modified electrode provided a promising alternative for DA analysis purpose and made great progresses in the detection for the dopamine by electrochemical sensors. [ABSTRACT FROM AUTHOR]

A simple and broadly applicable method was used to prepare the superhydrophobic coating, which reveals excellent performance with extremely water repellency and self-cleaning. By the use of hydrophobic PTEF or PVDF/TiO2 particles, the water repellence of the coating surface is enhanced; the property of coating with PVDF/TiO2 particles is better. Because of the addition of photocatalytic TiO2, the coating exhibits excellent self-cleaning ability and antifouling property with contact angle of water all above 150°. [ABSTRACT FROM AUTHOR]

Superhydrophobic coatings based on PDMS and TiO2-NPs/SiO2- NPs were prepared. Due to the photocatalytic property of TiO2-NPs, th e PDMS/TiO2-NPs coatings could remove the organic pollutes efficiently, and showed an excellent self-cleaning properties. The superhydrophobicity of the PDMS/TiO2-NPs coatings was still remained after 6 months in the open air, which is much better than the PDMS/SiO2-NPs coatings. [ABSTRACT FROM AUTHOR]

A hybrid material of diazoresin (DR) and ethylenediaminetetraacetic acid d isodium salt (EDTA-2Na) coated on to silica particles were synthesized and applied as adsorbents. The study of UV-vis spectrum revealed th at DR and EDTA could be successfully m odified on to silica. The effect of initial pH value of aqueous solution and dosage of th e adsorbents on the adsorption capability for heavy metal Cu(ll) ion were investigated and discussed. [ABSTRACT FROM AUTHOR]

This article described the preparation of opal ball with enhanced structural colors by using silica microspheres droplet templates on polytetrafluoroethylene (PTFE) superhydrophobic surfaces. The structural colors of the opal ball wasgreatly enhanced by incorporating carbon black nanoparticles (CB-NPs) into the voids of silica colloidal crystals in the dry self-assembly (DSA) process.The presence of CB-NPs in the structure did not lead to a shift of the reflection band, but enhanced the diffraction color by increased reflectance and suppressed transmission. [ABSTRACT FROM PUBLISHER]

Monodisperse P(St-MMA) colloids with diameters of 200 nm was synthesized successfully using emulsion polymerization firstly and then manufacture corresponding colloidal crystal which is used as template. Using fiber optic spectrometer to research the colloidal crystals before and after infiltrating sodium alginate and the reflection spectra shows the change of band gaps with Bragg law. The porous materials were studied using SEM. [ABSTRACT FROM PUBLISHER]

The relative reactivity of three hydroxyl groups in aconitine toward acetylation, chlorination, sulfonylation, and oxidation has been studied in this paper. The reduction of C-3 ketone and C-15 ketone derivatives of aconitine was also investigated. It was found that (1) the relative reactivity of three hydroxyl groups toward acetylation, chlorination, and sulfonylation is 3-OH>13-OH>>15-OH; (2) 3-OH is much more reactive than 15-OH toward oxidation; and (3) reduction of the carbonyl group at C-3 with NaBH4 generated a pair of C-3 epimers, while the reduction products of the carbonyl group at C-15 depend largely on the specific reducing agent and the absolute configuration of 16-OCH3. When the substrate has 16β-OCH3, its carbonyl group at C-15 can be reduced with NaBH4 to yield exclusively the 15α-OH-containing product. Upon replacement of reducing agent NaBH4 with LiAlH4, the C-15 carbonyl group can be reduced to yield a pair of C-15 epimers. On the other hand, when the substrate has 16α-OCH3, C-15 carbonyl group can only be reduced to generate 15α-OH-containing product. [ABSTRACT FROM AUTHOR]

A series of new bisbenzylisoquinoline alkaloids was partially synthesized from tetrandrine and fangchinoline and evaluated for their ability to reverse P-glycoprotein-mediated multidrug resistance (MDR) in cancer cells. All the test compounds increased the intracellular accumulation rate of rhodamine 123 in MDR cells (Bel7402 and HCT8), and most exhibited more potent MDR-reversing activity relative to the reference compound verapamil. Compounds 8, 10, 13, and 14 enhanced intracellular accumulation of doxorubicin in Bel7402 and HCT8 cells. [ABSTRACT FROM AUTHOR]