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In this note, we revisit the result of the Toeplitz matrix inversion formula proposed by Lv and Huang (2007), then we give a new structured perturbation analysis, which is useful for testing the stability of practical algorithms. It has been shown that our new upper bound is much sharper than the one they have given, especially when the size of the Toeplitz matrix is very large. Numerical experiments illustrate the effectiveness of our theoretical results. [ABSTRACT FROM AUTHOR]

In this study, a rapid and reliable pretreatment method called dispersive liquid-liquid microextraction (DLLME) was developed for the determination of 4(5)-methylimidazole (4-MeI) in beverages. The clean-up samples were analyzed by a high performance liquid chromatography coupled with triple quadrupole mass spectrometer (HPLC–MS/MS) using a reversed-phase C18 column (250 mm × 4.6 mm, 5 μm). The matrix effects and the fault of DLLME operation were corrected by the isotope dilution technique. The developed method exhibited the limit of quantification (0.3 μg L −1 ) and excellent linearity (R 2  = 0.999). In addition, the recovery values of 4-MeI in carbonated beverage were ranging from 102.60% to 113.22%, in soft drinks were ranging from 103.24% to 108.85%. The content 4-MeI was detected in thirteen beverage samples treated with DLLME and solid phase extraction method (SPE) (ranging from 6.4 to 165.5 μg L −1 ). The consistent result of 4-MeI content detected by DLLME and SPE method concluded that the established method on the basis of DLLME was rapid, robust and accurate for the trace 4-MeI determination in beverages. [ABSTRACT FROM AUTHOR]

Exponential discriminant analysis (EDA) is a generalized discriminant analysis method based on matrix exponential. It can essentially overcome the intrinsic difficulty of small-sample-size problem that exists in the classical linear discriminant analysis (LDA). However, for data with high dimensionality, one has to solve a large matrix exponential eigenproblem in this method, and the time complexity is dominated by the computation of exponential of large matrices. In this paper, we propose two inexact Krylov subspace algorithms for solving the large matrix exponential eigenproblem efficiently. The contribution of this work is threefold. First, we consider how to compute matrix exponential-vector products efficiently, which is the key step in the Krylov subspace method. Second, we compare the discriminant analysis criterion of EDA and that of LDA from a theoretical point of view. Third, we establish the relationship between the accuracy of the approximate eigenvectors and the distance to nearest neighbor classifier, and show why the matrix exponential eigenproblem can be solved approximately in practice. Numerical experiments on some real-world databases show the superiority of our new algorithms over their original counterpart for face recognition. [ABSTRACT FROM AUTHOR]

Reported is a facile and efficient methodology toward the synthesis of novel pyrimidine-fused spiropyrrolidine oxindoles via a multicomponent 1,3-dipolar cycloaddition reaction of pyrimidine-fused 3-alkenyloxindoles 1 with azomethine ylides (thermally generated in situ from sarcosine and formaldehyde). Products bearing adjacent quaternary–tertiary centers were smoothly obtained in high yields (up to 90% yield) with good diastereoselectivity (up to >20:1). In addition, their biological activity has been preliminarily demonstrated by in vitro evaluation against human lung cancer cells A549, human prostate cancer cells PC-3, and human leukemia cells K562 by the MTT-based assays, using the commercially available broad-spectrum anticancer drug of Cisplatin as a positive control. The results also demonstrated that most of the compounds showed considerable cytotoxicities to these three cell lines of K562, PC-3, and A549, showed comparably potent or even more potent than the positive control of Cisplatin (up to 3.0 times), and indicated that novel pyrimidine-fused spiropyrrolidine oxindoles may be potential leads for further biological screenings and may generate drug-like molecules. [ABSTRACT FROM AUTHOR]

Developed herein was an expedient method toward the synthesis of pyrimidine-fused 3-alkenyloxindoles 4 via a Knoevenagel condensation/S N Ar sequential reaction of pyrimidine aldehydes 1 with 2-oxindoles 2 using alcohols 3 as both the solvents and the reactants. A wide variety of products, which is a typical hybridization of two key structural skeletons of 3-alkenyl-oxindole and pyrimidine found in an array of biologically active natural products and pharmaceutical compounds, were obtained smoothly with high efficiency (up to 93% yield) and high ( E/Z )-selectivities (up to >20:1 E/Z ). Furthermore, their biological activity has been preliminarily demonstrated by in vitro evaluation against human prostate cancer cells PC-3, human lung cancer cells A549 and human leukemia cells K562 by the MTT-based assays using the commercially available broad-spectrum anticancer drug Cisplatin as a positive control. These results suggested that most of pyrimidine-fused 3-alkenyloxindoles 4 showed equipotent or more potent than the positive control of Cisplatin (up to 5.1 times), which suggested that pyrimidine-fused 3-alkenyloxindoles 4 may be potential leads for further biological screenings. [ABSTRACT FROM AUTHOR]

To translate the Strategic Learning Assessment Map into Chinese and validate it in Chinese nursing organisations. Nursing is the largest occupational organisation in the health sector and its adaptation and innovation are important for the realisation of sustainable development goals. Organisational learning is critical in cultivating the adaptive and innovative abilities of organisations, but there is limited research on its measurement. Although the Strategic Learning Assessment Map is a widely acknowledged organisational measurement instrument, it has not yet been adapted and validated in China. A cross-sectional study design was used. The Chinese version of the Strategic Learning Assessment Map was generated through forward-backward translation and was tested with a convenience sample of 2745 nurses from 7 administrative regions of mainland China. The internal consistency, content validity, structural validity and theoretical framework were examined. Results validated the theoretical framework and showed excellent content validity, convergent validity and fitness of the measurement model; only discriminant validity was not satisfactory. Cronbach's α values for the overall scale and its subscales ranged from 0.97 to 0.99. The Chinese version of the Strategic Learning Assessment Map is a reliable organisational learning instrument for Chinese nursing organisations. • The Chinese version of Strategic Learning Assessment Map is a reliable instrument. • The theoretical framework of Strategic Learning Assessment Map has been validated. • The organisational-level learning contributes most to organisational performance. • The feed-forward and feed-back learning is unbalanced in nursing organisation. • The effect of misalignment on organisational learning needs to be concerned. [ABSTRACT FROM AUTHOR]

Inspired by the chemistry and biology of isoflavones and pyrazolones, herein we report the first example of synthesis of 3-pyrazolyl isoflavones by two steps, starting from commercially available chromanones and pyrazolones. The [1,5]-proton transfer was used as a key strategy. All the 3-pyrazolyl isoflavones 3 , which are hard to synthesize by traditional methods, are smoothly obtained in up to 86% total yield. Interestingly, the product forms a stable 7-membered ring through intramolecular hydrogen bond between carbonyl group on chromone core and hydroxyl group on pyrazolone core, preventing further ketone-enol tautomerization. In particular, the products are featured with an intriguing combination of two privileged motifs including isoflavone and pyrazolone substructures, which might be valuable in medicinal chemistry. Image 1 • The first example of synthesis of 3-pyrazolyl isoflavones. • [1,5]-hydrogen transfer as the key step. • Potential biologically active molecules. [ABSTRACT FROM AUTHOR]

For the given signature operator H = I r ⊕ − I n − r , a pseudo-Jacobi matrix is a self-adjoint matrix relatively to a symmetric bilinear form 〈 ⋅ , ⋅ 〉 H , and it is the counterpart of a classical Jacobi matrix to the indefinite scalar product space setting. In this article, we consider an inverse eigenvalue problem for this class of matrices. The main concern is to construct an n × n pseudo-Jacobi matrix from a prescribed n -tuple of distinct real numbers and a Jacobi matrix of order not less than ⌊ n 2 ⌋ , such that its spectrum is this tuple and the given Jacobi matrix is its trailing principal submatrix. A divide-and-conquer scheme is used to solve this problem, and a necessary and sufficient condition under which the problem is solvable is presented. A numerical algorithm is designed to solve this pseudo-Jacobi matrix inverse eigenvalue problem according to the obtained results. Some illustrative numerical examples are also given to test the reconstructive algorithm. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel compound 1 possessed a benzophenone skeleton with a farnesyl side chain. • The methanol and dichloromethane extractions of H. lancasteri exhibited significant antiradical effects. • The IC 50 value of compound 4 was closest to that of the positive control drug ascorbic acid. • This work provided systematic biological targeted study on antiradical activity from active extracts to novel compound. A novel benzophenone lancasteriphenone A (1), one new natural product 2,4-dihydroxy-6-(3-methylbut-2-enoxy) phenyl]-phenylmethanone (2), along with two known compounds (3 and 4) were isolated and identified from the aerial parts of Hypericum lancasteri. Their structures were elucidated by means of spectroscopic techniques. Novel compound 1 possessed a benzophenone skeleton with a farnesyl side chain. DPPH radical scavenging activities were tested to determine the antioxidant potential of the methanol extract, dichloromethane extract as well as the isolated compounds (1 – 4). Its methanol and dichloromethane extracts exhibited significant antiradical effect with IC 50 values of 20.84 µg/mL and 60.63 µg/mL, respectively. Besides, the antiradical activitise of the compounds 1 – 4 from active dichloromethane extract were also tested. The DPPH radical scavenging rates of the compounds 1 – 4 were 33.07%, 24.59%, 17.67% and 86.56% at the concentration of 400 µmol/L, respectively, while the IC 50 value (97.53 µmol/L) of compound 4 was closest to that of the positive control drug ascorbic acid (IC 50 = 58.13 µmol/L). This work provided systematic biological targeted study on antioxidant activity from active extracts to novel compound, and shed a new light on the further antioxidant application research of H. lancasteri. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effect of bone mesenchymal stem cells (BMSCs) and BMSC neural-like cells (BMSC-Ns) on the spinal cord injury (SCI) in the rat model of SCI. BMSC-Ns were prepared from the third passage of BMSCs by induction of healthy cerebrospinal fluid (CSF) of an adult human. The SCI rat model was established through a surgical procedure, and after 7 days the rats were randomly divided into 3 (A, B and C) groups. Groups A (BMSC-Ns) and B (BMSCs) were treated with 1 × 10 6 /20 μl cells, while group C (saline) was treated with saline, all via intracerebroventricular injection. After transplantation, the BBB score of group A was significantly higher than that of group B, which in turn was significantly higher than that of group C ( P <  .05). The levels of Bdnf, Ngf, Ntf3 were statistically significantly higher in group A than those in groups B and C ( P <  .05). The levels of 5-HT, NA, Ach, DA, GABA in group A were significantly higher than those in groups B and C, whereas the level of Glu was significantly lower in group A than that in groups B and C ( P <  .05). The histopathological data showed remarkably less necrosis of the spinal cord in group A, compared to that in groups B and C. Transplanting BMSC-Ns or BMSCs into the lateral ventricles improved the neurological function of rats with SCI. Moreover, BMSC-Ns were significantly more effective than BMSCs, which provides a possible approach for the treatment of SCI. [ABSTRACT FROM AUTHOR]

Developed herein is a diversity-oriented one-pot multicomponent synthesis of polycyclic 3,3′- pyrrolidinyl-dispirooxindoles 3 via a multicomponent 1,3-dipolar cycloaddition event of 3-methyl-4-nitro-5-isatylidenyl-isoxazoles 2 with azomethine ylides (thermally generated in situ from isatins and proline or thioproline). Products bearing four consecutive stereocenters consist of two oxindole moieties and a polycyclic pyrrolidinyl core, including vicinal spiroquaternary stereocenters fused in one ring structure were smoothly obtained in high yields (up to 85% yield) with good diastereoselectivity (up to >20:1). Valuable features of this method were application of 3-methyl-4-nitro-5-isatylidenyl-isoxazoles as 1,3-dipolarophiles and the design of new hybrid architectures for biological screenings through the adequate fusion of these sub-units of isoxazole and 3,3′-pyrrolidinyl-dispirooxindole, generating drug-like molecules. [ABSTRACT FROM AUTHOR]

Described herein is a facile and efficient methodology toward the synthesis of Morusin scaffolds and Morusignin L scaffolds 4 – 9 and 12 via a novel three-step approach (Michael addition or prenylation, cyclization and cyclization) and use a rapid, microwave-accelerated cyclization as the key step. Furthermore, their biological activities have been preliminarily demonstrated by in vitro evaluation for anti-osteoporosis activity. These Morusin, Morusignin L and newly synthesized compounds 5b , 6a , 8e , 8f greatly exhibited the highest potency, especially at the 10 −5 mol/L (P < 0.01), and had good in vitro anti-osteoporosis activities using the commercially available standard drug Ipriflavone as a positive control. The mechanisms associated with anti-osteoporosis effects of these compounds may be through the inhibition of TRAP enzyme activity and bone resorption in osteoclasts, and promotion effect of osteoblast proliferation in vitro . The results indicated that Morusin scaffolds and Morusignin L scaffolds may be useful leads for further anti-osteoporosis activity screenings. [ABSTRACT FROM AUTHOR]

Described herein is a facile and efficient methodology for diversity-oriented one-pot multicomponent synthesis of 3-aminomethyl quaternary carbon oxindole fused five-membered carbocyclic spirooxindoles 5 via knoevenagel condensation/Michael/cyclization and then aminomethylation reaction. A wide variety of products with varying degrees of substitution around it, were obtained smoothly with high efficiency (up to overall yield 73% and >20:1 diastereoselectivity). In particular, their biological activities against these three cell lines K562, A549 and PC-3 have been evaluated. These results suggested that most of 3-aminomethyl quaternary carbon oxindole fused five-membered carbocyclic spirooxindoles 5 showed equipotent or more potent than the positive control of Cisplatin (up to 3.4 times). [ABSTRACT FROM AUTHOR]

Developed herein is a facile and efficient methodology toward the synthesis of novel turmerone motif-fused spiropyrrolidine oxindoles via a multicomponent 1,3-dipolar cycloaddition event of dienones 2 with azomethine ylides (thermally generated in situ from isatin derivatives and sarcosine). Products bearing adjacent quaternary–tertiary centers were smoothly obtained in high yields (up to 93% yield) with good diastereoselectivity (up to >20:1). In addition, their biological activity has been preliminarily demonstrated by in vitro evaluation against human lung cancer cells A549 and human leukemia cells K562 by the MTT-based assays, using the commercially available standard drug of Cisplatin as a positive control. The results also demonstrated that most of the compounds showed considerable cytotoxicities to these two cell lines of K562 and A549, showed comparably potent or even more potent than the positive control of Cisplatin (up to 5.1 times), and indicated that novel turmerone motif-fused spiropyrrolidine oxindoles may be potential leads for further biological screenings and may generate drug-like molecules. [ABSTRACT FROM AUTHOR]

A facile and efficient methodology was developed for the synthesis of multifunctional polycyclic spiropyrrolidine oxindoles bearing mesityl oxide unit via a three-component 1,3-dipolar cycloaddition reaction of dienones 2 with azomethine ylides (thermally generated in situ from isatin derivatives and proline or thioproline). Products bearing adjacent four chiral carbon centers were smoothly obtained in high yields (up to 98% yield) with diastereoselectivities up to >20:1. Furthermore, the key structural characteristic of the products of such a reaction is the natural product ingredient turmerone motif fused at the 3-position of the spirooxindole core, with varying degrees of substitution around it. In addition, their biological activity has been preliminarily demonstrated by in vitro evaluation against human prostate cancer cells PC-3, human lung cancer cells A549 and human leukemia cells K562 by the MTT-based assays, using the commercially available standard drugs Cisplatin as a positive control. These results suggested there is a trend that lipophilicity groups improve the potency, and also suggested an mesityl oxide moiety located in the polycyclic spiropyrrolidine oxindoles is beneficial for the activity. The results also demonstrated that most of the compounds showed considerable cytotoxicities to these three cell lines K562, A549 and PC-3, and indicated that polycyclic spiropyrrolidine oxindole analogs bearing mesityl oxide unit may be potential leads for further antitumor activity screenings. [ABSTRACT FROM AUTHOR]

A series of structurally diverse chrysin-chromene-spirooxindole hybrids were designed, synthesized via a Knoevenagel/Michael/cyclization of chrysin and isatylidene malononitrile derivatives through utilizing a hybrid pharmacophore approach. The newly synthesized compounds were evaluated for their in vitro anticancer activity, and most of the compounds showed stronger anti-proliferative activity than parent compound chrysin. In particular, compound 3e had the highest cytotoxicity towards A549 cells (IC 50 = 3.15 ± 0.51 μM), and had better selectivity in A549 cells and normal MRC-5 cells. Furthermore, compound 3e could significantly inhibit the proliferation and migration of A549 cells in a dose-dependent manner, as well as induce the apoptosis possibly through mitochondria-mediated caspase-3/8/9 activation and multi-target co-regulation of the p53 signaling pathway. Thus, our results provide in vitro evidence that compound 3e may be a potential candidate for the development of new anti-tumour drugs. Unlabelled Image • The first example of flavonoid-fused spirooxindoles. • A molecular hybridization strategy. • Compound 3e induced cancer cell apoptosis as a potential anticancer agent. [ABSTRACT FROM AUTHOR]