Ensemble feature selection in medical datasets: Combining filter,wrapper, and embedded feature selection results

Feature selection is a process aimed at filtering out unrepresentative features from a given dataset, usually allowing the later data mining and analysis steps to produce better results. However, different feature selection algorithms use different criteria to select representative features, making it difficult to find the best algorithm for different domain datasets. The limitations of single feature selection methods can be overcome by the application of ensemble methods, combining multiple feature selection results. In the literature, feature selection algorithms are classified as filter, wrapper, or embedded techniques. However, to the best of our knowledge, there has been no study focusing on combining these three types of techniques to produce ensemble feature selection. Therefore, the aim here is to answer the question as to which combination of different types of feature selection algorithms offers the best performance for different types of medical data including categorical, numerical, and mixed data types. The experimental results show that a combination of filter (i.e., principal component analysis) and wrapper (i.e., genetic algorithms) techniques by the union method is a better choice, providing relatively high classification accuracy and a reasonably good feature reduction rate.     

New cytotoxic withanolides from Physalis peruviana

Investigation of the extracts of Physalis peruviana L. has led to the isolation of seven new withanolides, phyperunolide A (1), phyperunolide B (2), phyperunolide C (3), phyperunolide D (4), peruvianoxide (5), phyperunolide E (16), and phyperunolide F (17) together with ten known withanolides. The structure and absolute stereochemistry of all compounds were elucidated on the basis of CD and NMR spectral analysis, respectively. Compounds 1, 6, 7, and 9 showed cytotoxicity against lung cancer (A549), breast cancer (MDA-MB-231 and MCF7), and liver cancer (Hep G2 and Hep 3B) cancer cell lines. The presence of 5β,6β-epoxy-2-en-1-ones in withanolides is greatly helpful in cytotoxicity, it is a key known important factor to cytotoxicity; however, interestingly, the unusual 5-chloride withanolide, 9, displayed significant activity.     

脉冲磁场对皮层神经元瞬时外向钾电流影响的初步实验研究

摘要：目的：随着现代工业的发展,磁场对人体的作用日趋广泛,越来越多的磁疗仪器的产生,并有着确实的疗效,但其机理并未明确,本文通过实验研究了脉冲磁场对小鼠皮层细胞的瞬时外向钾离子通道影响,以求能到得到更明确的机理的解释。方法：瞬时外向钾电流具有维持兴奋性细胞静息电位,决定细胞的兴奋性等重要作用,本试验采用频率为15Hz、强度为1.4mT的超低频脉冲磁场对小鼠的脑皮层神经细胞进行刺激,而后应用全细胞膜片钳技术测量并研究其瞬时外向钾电流特性。结果：实验发现超低频脉冲磁场对瞬时外向钾电流IA有一定的抑制作用,脉冲磁场作用可显著地影响通道的激活,对照组和脉冲磁场作用组通道半数激活电压分别为13.25±2.22mV和30.98±4.11mV（n＝6, P<0.05）,斜率因子分别为24.00±2.05mV和23.30±2.13mV（n=6,P<0.05）。结论：结果表明脉冲磁场作用皮层神经细胞可以改变其瞬时外向钾通道特性,从而影响动作电位的形成和发放频率,调节神经元的生理功能,有利于受损神经元的恢复和再生。     

Antiallergic Phorbol Ester from the Seeds of Aquilaria malaccensis

The Aquilaria malaccensis (Thymelaeaceae) tree is a source of precious fragrant resin, called agarwood, which is widely used in traditional medicines in East Asia against diseases such as asthma. In our continuous search for active natural products, A. malaccensis seeds ethanolic extract demonstrated antiallergic effect with an IC₅₀ value less than 1 µg/mL. Therefore, the present research aimed to purify and identify the antiallergic principle of A. malaccensis through a bioactivity-guided fractionation approach. We found that phorbol ester-rich fraction was responsible for the antiallergic activity of A. malaccensis seeds. One new active phorbol ester, 12-O-(2Z,4E,6E)-tetradeca-2,4,6-trienoylphorbol-13-acetate, aquimavitalin (1) was isolated. The structure of 1 was assigned by means of 1D and 2D NMR data and high-resolution mass spectrometry (HR-MS). Aquimavitalin (1) showed strong inhibitory activity in {"type":"entrez-nucleotide","attrs":{"text":"A23187","term_id":"833253","term_text":"A23187"}}A23187- and antigen-induced degranulation assay with IC₅₀ values of 1.7 and 11 nM, respectively, with a therapeutic index up to 71,000. The antiallergic activities of A. malaccensis seeds and aquimavitalin (1) have never been revealed before. The results indicated that A. malaccensis seeds and the pure compound have the potential for use in the treatment of allergy.     

Phyto-SERM Constitutes from Flemingia macrophylla

The methanolic extract of Flemingia macrophylla roots exhibited significant estrogenic activity in the transgenic plant assay system which was comparable to the activity of soybean extract. Utilizing estrogenic activity-guided fractionation, one new compound, fleminigin, together with 23 known compounds were isolated from F. macrophylla roots’ methanolic extract. The structure of the new compound was identified based on intensive spectroscopic analysis and the full spectral data for one of the isolated compounds, flemichin E, was introduced for the first time in the current investigation. The estrogenic and anti-estrogenic activities of the isolated compounds were evaluated revealing that the isolated isoflavonoids may act as partial estrogen agonists, as well as antagonists. Additionally, the anti-inflammatory and the cytotoxic activities of the isolated compounds were studied. These results suggested the potential applications of F. macrophylla extract and its isolated compounds as selective estrogen receptor modulators (SERMs).     

Immunostimulatory effect of Antrodia camphorata extract on functional maturation of dendritic cells

Dendritic cells (DCs) are now recognised as the most potent professional antigen presenting cells (APCs) involved in initiating primary immune responses. The medicinal mushroom Antrodia camphorata (AC) is one of the most popular chemopreventive mushrooms in Taiwan. Polysaccharides of mushroom products are among emerging new agents that activate maturation and functions of DCs. The aim of this study is to investigate the immunomodulating activity of A. camphorata extract (ACW) on functional maturation of DCs. Compared with lipopolysaccharides (LPS), ACW effectively promoted the functional maturation of DCs in the expression of phenotypic characteristics and IL-12 production and chemotaxic activity. Moreover, ACW increased the phosphorylation of Akt, p38, and JNK/MAPKs in DCs. Specific inhibitors, SB203580 and LY94002, significantly blocked the ACW-induced up-regulation of costimulatory factor expression, IL-12 production. These findings suggest that ACW is a potent adjuvant for cancer immunotherapy and promotes Th1 immune responses.     

A novel steganography scheme for video H.264/AVC without distortion drift

Multimedia Tools and Applications - Many steganography schemes have been proposed for video sequences. However, the embedding capacity obtained by these schemes is still unsatisfactory. In this...     

Identification of phenolic antioxidants from Sword Brake fern (Pteris ensiformis Burm.)

Sword Brake fern (Pteris ensiformis Burm.) is one of the most common ingredients of traditional herbal drinks in Taiwan. In an effort to identify antioxidants from the aqueous extract of Sword Brake fern (SBF), the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity-guided isolation was employed. Three new compounds, kaempferol 3-O-α-l-rhamnopyranoside-7-O-[α-d-apiofuranosyl-(1-2)-β-d-glucopyranoside] (1), 7-O-caffeoylhydroxymaltol 3-O-β-d-glucopyranoside (3) and hispidin 4-O-β-d-glucopyranoside (4), together with five known compounds, kaempferol 3-O-α-l-rhamnopyranosid-7-O-β-d-glucopyranoside (2), caffeic acid (5), 5-O-caffeoylquinic acid (6), 3,5-di-O-caffeoylquinic acid (7) and 4,5-di-O-caffeoylquinic acid (8) were isolated and determined on the basis of spectroscopic analyses. HPLC with UV detector was further employed to analyze the content of each compound in SBF based on the retention time by comparison with isolated pure compounds. It was found that the most abundant phenolic compound was compound 3, followed by compounds 7 and 4. The di-O-caffeoylquinic acids (7 and 8) have the strongest DPPH scavenging potential with IC₅₀ around 10 μM and the highest Trolox equivalent antioxidant capacity (TEAC) about 2 mM. This data indicates that SBF is rich in phenolic antioxidants.     

Identification of antioxidants from rhizome of Davallia solida

Davallia solida rhizome has long been used as an herb tonic to treat osteoporosis, arthralgia, and arthritis. The aqueous extract of D. solida rhizome contains a high content of phenolic compounds [210.8 ± 4.6 mg catechin equivalents (CE)/g dry weight] and shows a strong 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity (IC₅₀ = 15.93 ± 1.21 μg dry weight/ml). Further solvent partition of the aqueous extract yielded chloroform, n-butanol, and water layers. Among them, n-butanol layer has the highest phenol content (806.3 ± 12.3 mg CE/g dry weight) and DPPH scavenging potential (IC₅₀ = 3.93 ± 0.31 μg dry weight/ml). Isolation and purification from the n-butanol layer identified 12 compounds. They included four new compounds: 3′-O-p-hydroxybenzoylmangiferin (1), 4′-O-p-hydroxybenzoylmangiferin (2), 6′-O-p-hydroxybenzoylmangiferin (3), and 3-O-p-hydroxybenzoylmangiferin (4); as well as eight known compounds: mangiferin (5), 2-C-β-d-xylopyranosyl-1,3,6,7-tetrahydroxyxanthone (6), 4β-carboxymethyl-(−)-epicatechin (7), 4β-carboxymethyl-(−)-epicatechin methyl ester (8), eriodictyol (9), eriodictyol-8-C-β-d-glucopyranoside (10), icariside E₅ (11), and icariside E₃ (12). DPPH scavenging and Trolox equivalent antioxidant capacity (TEAC) analyses revealed that the most potent antioxidants are 1, 2, and 3, which exerted more than triple activity as compared with the positive controls, α-tocopherol and Trolox.     

Fruit and vegetable consumption and risk of cardiovascular disease: A meta-analysis of prospective cohort studies

A meta-analysis of prospective cohort studies was conducted to examine the relation between fruit and vegetables (FV) consumption and the risk of cardiovascular disease (CVD). We searched PubMed and EMBASE up to June 2014 for relevant studies. Pooled relative risks (RRs) were calculated and dose–response relationship was assessed. Thirty-eight studies, consisting of 47 independent cohorts, were eligible in this meta-analysis. There were 1,498,909 participants (44,013 CVD events) with a median follow-up of 10.5 years. The pooled RR (95% confidence interval) of CVD for the highest versus lowest category was 0.83 (0.79–0.86) for FV consumption, 0.84 (0.79–0.88) for fruit consumption, and 0.87 (0.83–0.91) for vegetable consumption, respectively. Dose–response analysis showed that those eating 800 g per day of FV consumption had the lowest risk of CVD. Our results indicate that increased FV intake is inversely associated with the risk of CVD. This meta-analysis provides strong support for the current recommendations to consume a high amount of FV to reduce CVD risk.