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91.
High dimensional data increase the dimension of space and consequently the computational complexity and result in lower generalization. From these types of classification problems microarray data classification can be mentioned. Microarrays contain genetic and biological data which can be used to diagnose diseases including various types of cancers and tumors. Having intractable dimensions, dimension reduction process is necessary on these data. The main goal of this paper is to provide a method for dimension reduction and classification of genetic data sets. The proposed approach includes different stages. In the first stage, several feature ranking methods are fused for enhancing the robustness and stability of feature selection process. Wrapper method is combined with the proposed hybrid ranking method to embed the interaction between genes. Afterwards, the classification process is applied using support vector machine. Before feeding the data to the SVM classifier the problem of imbalance classes of data in the training phase should be overcame. The experimental results of the proposed approach on five microarray databases show that the robustness metric of the feature selection process is in the interval of [0.70, 0.88]. Also the classification accuracy is in the range of [91%, 96%]. 相似文献
92.
The unique viscoelastic nature of axons is thought to underlie selective vulnerability to damage during traumatic brain injury. In particular, dynamic loading of axons has been shown to mechanically break microtubules at the time of injury. However, the mechanism of this rate-dependent response has remained elusive. Here, we present a microstructural model of the axonal cytoskeleton to quantitatively elucidate the interaction between microtubules and tau proteins under mechanical loading. Mirroring the axon ultrastructure, the microtubules were arranged in staggered arrays, cross-linked by tau proteins. We found that the viscoelastic behavior specifically of tau proteins leads to mechanical breaking of microtubules at high strain rates, whereas extension of tau allows for reversible sliding of microtubules without any damage at small strain rates. Based on the stiffness and viscosity of tau proteins inferred from single-molecule force spectroscopy studies, we predict the critical strain rate for microtubule breaking to be in the range 22–44 s−1, in excellent agreement with recent experiments on dynamic loading of micropatterned neuronal cultures. We also identified a characteristic length scale for load transfer that depends on microstructural properties and have derived a phase diagram in the parameter space spanned by loading rate and microtubule length that demarcates those regions where axons can be loaded and unloaded reversibly and those where axons are injured due to breaking of the microtubules. 相似文献
93.
Hossein Mahi Arash Rasekh J.P. Michaud Parviz Shishehbor 《Entomologia Experimentalis et Applicata》2014,153(1):10-19
Cold storage is one means of preserving parasitoids prior to release in augmentation biological control programs. This study examined the feasibility of storing larval and pupal stages of a sexual population of Lysiphlebus fabarum Marshall (Hymenoptera: Braconidae: Aphidiinae) at 6 ± 1 and 8 ± 1 °C, 50–60% r.h., and L14:D10 photoperiod. These life stages were stored for periods of 1, 2, and 3 weeks under fluctuating thermal regimes (2 h daily at 21 ± 1 °C). Generally, pupae gave better results than larvae, and 6 °C was better than 8 °C, considering wasp survival, wasp size (tibial and antennal lengths), egg load, and egg size. The best results were obtained with pupae stored for 2 weeks under a fluctuating temperature regime at 6 °C. Females emerging from this treatment did not differ from controls (developing directly at 21 °C) in body size, egg size, or progeny sex ratio, and suffered less than 20% mortality. Egg loads were reduced in these wasps, but the reductions were substantially less than occurred in other 2‐week‐storage treatments. Wasps stored in this manner successfully parasitized similar numbers of aphids as controls and produced similar progeny sex ratios. These results reveal a suitable set of low‐temperature conditions that can be used to delay the development of L. fabarum for 2 weeks with minimal impact on wasp fitness. 相似文献
94.
The following paper describes the foraminiferal fauna and associated faunal assemblages of the bedded and reef carbonates of the Upper Triassic (most probably Rhaetian) Nayband Formation, which are exposed in a section south of the small town of Bagher-Abad, northeast of Esfahan. Foraminifers are extremely rare in sponge- or coral-dominated bioconstructions and in the bedded carbonates of the Nayband Formation in central Iran. Some carbonate beds are composed of bioclastic wackstone/packstone. These are exposed in the solenoporacean horizon at the uppermost part of the section. Here, the aulotortid- and trocholinid-type foraminifers are relatively abundant. The following foraminiferal taxa with different abundances were found within the carbonates of the investigated section: Trocholina umbo Frentzen, T. turris Frentzen, T. gracilis Blau, Aulotortus tumidus (Kristan-Tollmann), Aulotortus tenuis (Kristan), Aulotortus friedli (Kristan-Tollmann), Coronipora etrusca (Pirini), Semiinvoluta clari Kristan, Turrispirillina? licia variabilis Blau, Galeanella? laticarinata Al-Shaibani, Carter and Zaninetti, Ophthalmidium sp., Agathammina sp., “Sigmoilina” schaeferae Zaninetti, Planiinvoluta carinata Leischner, Planiinvoluta sp., Nubecularia sp., Endothyra sp., Paeolituonella sp. and some sessile agglutinated and nodosariid types. All mentioned taxa are very rare, except the involutinid and trocholinid types. The following species are described as new: Trocholina blaui nov. sp., Spirilina? iranica nov. sp., and Coronipora serraforma nov. sp. Trocholina blaui is usually attached to solenoporacean thalli. Four foraminiferal associations, which are named after the occurrence of the abundant species, were distinguished as Aulotortus tumidus association, Aulotortus friedli association, Trocholina umbo association, and Trocholina blaui association. Aulotortid types and Trocholina umbo were found within the bioclastic wackstone/packstone carbonates. Trocholina blaui is abundant in solenoporacean framestones. The foraminiferal association of investigated carbonates contains a mixed fauna, known from Upper Triassic–Liassic in the Tethyan realm. Carbonates of the whole investigated section are dated—due to occurrence of the genus Aulotortus, with species A. tumidus (Kristan-Tollmann), A. tenuis (Kristan), and A. friedli (Kristan-Tollmann)—as Upper Triassic (most probably Rhaetian). The “typical” foraminifers occurring in the reef biotopes in the northwestern Tethys are either missing or extremely rare in the Iranian bioconstructions. 相似文献
95.
Farshad Shadanloo Mohammad Hasan Najafi Sayed Morteza Hosseini Mehdi Hajian Mohsen Forouzanfar Kamran Ghaedi Parvaneh Abedi Somaye Ostadhosseini Laleh Hosseini Morad‐Pasha Eskandari‐Nasab Mohammad Hossein Nasr Esfahani 《Molecular reproduction and development》2010,77(10):868-875
In relation to the growing recent interest in the establishment of sperm‐mediated gene transfer (SMGT) technology as a convenient and effective method for the simple production of transgenic animals, in this study the possibility of using SMGT to produce transgenic caprine embryos was investigated for the first time. Buck sperm were directly incubated with different concentrations (0–500 ng) of pcDNA/his/Lac‐Z plasmid and used for IVF or ICSI. Sperm used for ICSI were categorized into motile or live‐immotile group before being injected into oocytes. In a separate experiment, dead sperm prepared by repeated freezing/thawing were used for DNA‐incubation before ICSI. Sham injection was carried out by intracytoplasmic injection of approximately the same volume of media containing different doses of DNA using an ICSI needle. Transgene expression and transmission were detected by X‐Gal staining and PCR analysis of developed embryos, respectively. A reasonable blastocyst rate was observed in all the groups. Only embryos in the sham group were negative for transgene transmission. Transgene expression was completely dependent on the delivery technique and status of sperm, and was only observed in the live‐immotile and dead ICSI groups. The results of this study showed that the technique (IVF vs. ICSI vs. sham injection), sperm status (motile vs. live‐immotile vs. dead) and to some extent DNA concentration affect embryo development, transgene transmission and expression. Mol. Reprod. Dev. 77:868–875, 2010. © 2010 Wiley‐Liss, Inc. 相似文献
96.
Jianying Li S. Hossein Hosseini Moghaddam Xiang Chen Ming Chen Boxiong Zhong 《Amino acids》2010,39(3):751-761
Insect head is comprised of important sensory systems to communicate with internal and external environment and endocrine
organs such as brain and corpus allatum to regulate insect growth and development. To comprehensively understand how all these
components act and interact within the head, it is necessary to investigate their molecular basis at protein level. Here,
the spectra of peptides digested from silkworm larval heads were obtained from liquid chromatography tandem mass spectrometry
(LC–MS/MS) and were analyzed by bioinformatics methods. Totally, 539 proteins with a low false discovery rate (FDR) were identified
by searching against an in-house database with SEQUEST and X!Tandem algorithms followed by trans-proteomic pipeline (TPP)
validation. Forty-three proteins had the theoretical isoelectric point (pI) greater than 10 which were too difficult to separate by two-dimensional gel electrophoresis (2-DE). Four chemosensory proteins,
one odorant-binding protein, two diapause-related proteins, and a lot of cuticle proteins, interestingly including pupal cuticle
proteins were identified. The proteins involved in nervous system development, stress response, apoptosis and so forth were
related to the physiological status of head. Pathway analysis revealed that many proteins were highly homologous with the
human proteins which involved in human neurodegenerative disease pathways, probably implying a symptom of the forthcoming
metamorphosis of silkworm. These data and the analysis methods were expected to be of benefit to the proteomics research of
silkworm and other insects. 相似文献
97.
Mirzajani F Ghassempour A Jalali-Heravi M Mirjalili MH 《Phytochemical analysis : PCA》2010,21(6):544-549
Introduction – Recently, there have been growing attention on the modification and optimisation of new extraction and quantification methods, caused by the lack of environmentally friendly methodologies for the extraction of phytochemicals from complex matrices. In the case of pharmaceutical compounds, not only the extraction procedure but also the analysis method should be efficient, precise, fast and easy. Objectives – The essential pharmaceutical characteristics and trace concentration of withanolides led us to modify and optimise the previously reported extraction and quantification procedure for withaferin A (WA) as a candidate for withanolides. Matrial and methods – The WA from the air‐dried aerial part of Withania somnifera Dunal. was extracted using a microwave‐assisted extraction (MAE) technique. Four variables affecting the extraction procedure were optimised using the central composite design approach. The method of high‐performance thin‐layer chromatography assay was validated and applied for the quantification of each experiment. Results – The optimum values of factors were: extraction time (150 s), extraction temperature (68°C) and 17 mL of methanol : water in the ratio 25 : 75 as extracting solvent. The solvent system consisted of ethyl acetate : toluene : formic acid : 2‐propanol (7.0 : 2.0 : 0.5 : 0.5, v/v/v/v), and densitometric scanning at 220 nm was applied for the analysis. The dynamic linear range, LOD, LOQ and recovery with the inter‐day, and intra‐day RSDs of the developed method indicated the validity of the method. Conclusion – A pressurised MAE method for extracting WA from the plant's aerial part was optimised using factorial‐based design. The net effect of time, temperature, solvent volume and its ratio suggests that the yield of WA increases until each factor reaches its optimum value, and decreases with further increase in temperature or solvent ratio. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
98.
Heshmat Omidi Zeinaldin Tahmasebi Hassan Ali Naghdi Badi Hossein Torabi Mohammad Miransari 《Comptes rendus biologies》2010,333(3):248-254
Vegetable oils with a high relative amount of unsaturated fatty acids are of great significance for human health. There is not any data on the effects of tillage practices on fatty acid composition of canola (Brassica napus L.). Hence, in a 2-year split plot experiment, the effects of different tillage systems (no (NT), minimum (MT) and conventional tillage (CT)), canola genotypes (Hyola 401 (V1) and PF (V2)) and sowing dates (including Sep. 8, 23 and Oct. 7) on the fatty acid composition of canola were evaluated. Tillage practices and the combination of canola genotypes and sowing dates were randomized to the main and sub-plots, respectively. The highest oleic acid content was the result of combining NT, V1 and Sep. 23, and the lowest was related to the combination of CT, V2 and Oct. 7. While the combination of NT, V1 and D1 resulted in the highest amount of unsaturated fatty acids, this amount was the lowest for the combination of CT, V2 and Sep. 23. For the selection of an appropriate canola producing strategy, all these parameters must be taken into account. The combination of NT, V1 and Sep. 23 may be the most favorable cropping strategy for canola production under a Mediterranean climate. 相似文献
99.
Khadijeh Zare Hossein Nazemiyeh Ali Movafeghi Mahmood Khosrowshahli Alireza Motallebi-Azar Mohammadreza Dadpour Yadollah Omidi 《Plant Cell, Tissue and Organ Culture》2010,100(2):157-164
An in vitro cell suspension culture of Echium italicum was established and assayed for the production of shikonin and alkannin derivatives. Callus tissues were induced from cotyledon
explants of the plant incubated onto the solidified B5 medium. A two-liquid-phase system suspension culture was then established
to elicit pigments of shikonin and alkannin derivatives using liquid paraffin. The presence of liquid paraffin efficiently
induced production of pigments in cultured cells. The production and/or accumulation of these compounds in the E. italicum cells was examined using fluorescence microscopy as the naphthoquinone molecules display autofluorescent properties. Phytochemical
analysis of the n-hexane extract of the medium was also carried out using preparative HPLC. The chemical structure of shikonin and alkannin
derivatives were characterized by UV, 1H-NMR, and 13C-NMR techniques. Based on our findings, this bioprocess engineering approach
resulted in induction of shikonin and alkannin derivatives, whereupon it may be recruited for production of these important
secondary metabolites. 相似文献
100.
Davoud Nouri Inanlou Bagher Yakhchali Hossein Khanahmad Mossa Gardaneh Hesam Movassagh Reza Ahangari Cohan Mehdi Shafiee Ardestani Reza Mahdian Sirous Zeinali 《Biotechnology letters》2010,32(11):1615-1621
We have developed an integrase-defective lentiviral (LV) vector in combination with a gene-targeting approach for gene therapy
of β-thalassemia. The β-globin gene-targeting construct has two homologous stems including sequence upstream and downstream
of the β-globin gene, a β-globin gene positioned between hygromycin and neomycin resistant genes and a herpes simplex virus
type 1 thymidine kinase (HSVtk) suicide gene. Utilization of integrase-defective LV as a vector for the β-globin gene increased the number of selected clones
relative to non-viral methods. This method represents an important step toward the ultimate goal of a clinical gene therapy
for β-thalassemia. 相似文献