This paper deals with the optimization of kurtosis for complex-valued signals in the independent component analysis (ICA) framework, where source signals are linearly and instantaneously mixed. ...Inspired by the recently proposed reference-based contrast schemes, a similar contrast function is put forward, based on which a new fast fixed-point (FastICA) algorithm is proposed. The new optimization method is similar in spirit to the former classical kurtosis-based FastICA algorithm but differs in the fact that it is much more efficient than the latter in terms of computational speed, which is significantly striking with large number of samples. The performance of this new algorithm is confirmed through computer simulations.
ZnO naorods on ZnO-coated seed substrates were fabricated by solution chemical method from Zn(NO
3)
2/NaOH under assisted electrical field. The working mechanism of electrical field was analyzed and ...the factors affecting the rod growth such as potential, precursor concentration and growth temperature were elucidated. The structural and optical properties are characterized by SEM, TEM, XRD, HRTEM and UV–vis. The results indicated that the nanorods have wurtzite structure without electrical field and are primarily of zincite structure under electrical field; when the electrical field is 1.1–1.3
V, not only the elevation of ion diffusion and adsorption lower the crystallite/solution interfacial energy and then the crystal nucleation barrier by increasing charge intensity, but also the production of H
+ through oxidation of OH
− increases properly the degree of solution supersaturation near the substrate, and thus lowers the activation energy. Both the two processes do favor to rod growth. With increasing precursor concentration in this system, the average diameter and length of ZnO nanorods increase, leading to decreasing of optical transmittance. The maximum rod growth rate at given concentration of Zn
2+ occurs at a specific temperature.
Hyperthermia, a modality of cancer therapy, has been known as a stress to induce apoptosis. However, the molecular mechanism of heat shock-induced apoptosis, especially on roles of intracellular ...oxidative stress, is not fully understood. First, when human lymphoma U937 cells were treated with heat shock (44 degrees C, 30 min), the fraction of apoptosis, revealed by phosphatidylserine externalization, increased gradually and peaked at 6 hr after the treatment. In contrast, intracellular superoxide formation increased early during the heat shock treatment and peaked at 30 min after the treatment. When the cells were treated with heat shock in the presence of alpha -phenyl-N-tert-butylnitrone (PBN) and its derivatives, which are potent antioxidants, the DNA fragmentation was inhibited in an order according to the agents' hydrophobicity. PBN showing the highest inhibitory effects suppressed not only intracellular superoxide formation but also various apoptosis indicators. cDNA microarray was employed to analyze gene expression associated with heat shock-induced apoptosis, and the time-course microarray analysis revealed 5 groups showing changes in their pattern of gene expression. Among these genes, c-jun mRNA expression showed more than 40 fold increase 2 hr after heat treatment. The expression level of c-jun mRNA verified by quantitative real-time PCR was about 20 fold increase, and c-jun expression was similarly suppressed by PBN and its derivatives. These results suggest that the change of c-jun expression is an excellent molecular marker for apoptosis mediated by intracellular oxidative stress induced by heat shock.
The elliptic (v_{2}) and triangular (v_{3}) azimuthal anisotropy coefficients in central ^{3}He+Au, d+Au, and p+Au collisions at sqrts_{NN}=200 GeV are measured as a function of transverse momentum ...(p_{T}) at midrapidity (|η|<0.9), via the azimuthal angular correlation between two particles both at |η|<0.9. While the v_{2}(p_{T}) values depend on the colliding systems, the v_{3}(p_{T}) values are system independent within the uncertainties, suggesting an influence on eccentricity from subnucleonic fluctuations in these small-sized systems. These results also provide stringent constraints for the hydrodynamic modeling of these systems.
To explore the clinical value of intraoperative magnetic resonance imaging (iMRI) coregistration combined with position emission tomography/computed tomography (PET/CT) in stereotactic brain biopsy.
...Forty nine patients with intracranial lesions were operated by stereotactic biopsy from June 2010 to June 2015 in Tianjin Medical University General Hospital. Seventeen patient's operation was guided by iMRI only (group A), thirty two patients' operation was guided by iMRI and PET/CT (group B). The diagnosis success rate and operation related complications were compared between the two groups.
PET/CT and iMRI were integrated successfully in all cases of group B. Fourteen patients (82.4%) of group A and all 32 patients (100%) of group B had final diagnosis confirmed by histopathological and immunohistochemical observation. The diagnosis success rate of group B was higher than group A (P<0.05). There were 5 patients in total who had postoperative complication, 2 (11.8%) in group A and 3 (9.3%) in group B, but the di
Hypomethylation of the O6-methylguanine-DNA-methyltransferase (MGMT) promoter in glioma cells has been associated with temozolomide resistance. S-adenosylmethionine (SAM), which is produced during ...folate metabolism, is the main source of methyl groups during DNA methylation. As a key enzyme during folate metabolism, polymorphisms of 5,10-methylenetetrahydrofolate reductase (MTHFR) may regulate folate end-products. We investigated the effect of typical polymorphisms of MTHFR (C677T and A1298C) on MGMT methylation based on different serum folate levels in patients with glioma from Northeast China. A total of 275 patients with glioma and 329 without malignant tumors were tested. Serum folate concentration was assayed by using the electrochemiluminescence immunoassay. MTHFR polymorphisms were detected by Taqman-Fluorescence quantitative polymerase chain reaction (PCR). Methylation-specific PCR was used to assess MGMT methylation. The constituent ratio of glioma patients below the serum folate biological reference value was significantly higher than that of the control population (P < 0.001). In patients with oligodendroglioma and glioblastoma, heterozygotes for the A1298C mutation were found in higher frequency than homozygotes or wild types (oligodendroglioma, P < 0.001; glioblastoma, P < 0.01). When grouped by the median or biological reference value of serum folate, only homozygotes for C677T with low levels of folate were significantly associated with decreased methylation of MGMT (median, P < 0.001; biological reference value, P = 0.036). These data suggest that, in combination with a negative folate balance in glioma patients, T/T genotypes in MTHFR C677T may be associated with MGMT demethylation.
To investigate the threshold effects of photosynthetically active radiation (PAR) and soil mass water content (MWC) on photosynthetic efficiency parameters of Ziziphus jujuba Mill var. spinosa and to ...understand the adaptability of Z. jujuba to light and soil moisture variation, we determined optimal MWC and PAR for Z. jujuba which maintained higher net photosynthetic rate (P N) and water use efficiency (WUE). Using a Li-6400 portable photosynthesis system, we measured light response of P N, transpiration rate (E), WUE, and other gas-exchange parameters of 3-year-old Z. jujuba shrubs in a range of soil moisture conditions. The results showed that the leaf photosynthetic rate and WUE of Z. jujuba had a significant response to MWC and PAR. Given increases in the MWC (7.1–17.6%), the plant's light compensation point decreased and its light saturation point (LSP), apparent quantum yield, and maximum P N increased. When MWC was at 17.6%, the low and high light use efficiency of Z. jujuba was all maximal. P N obviously increased with increasing MWC (9.2–17.6%). However, P N decreased when MWC was too high or low. When PAR ranged from 800 to 1200 μmol m ⁻ ² s ⁻ ¹, P N and WUE were higher and the LSPs of P N and WUE ranged between 706 and 1209 μmol m ⁻ ² s ⁻ ¹. These data indicate that Z. jujuba possessed higher adaptability to light conditions. Based on photosynthetic efficiency parameters, the soil moisture availability and productivity of Z. jujuba were classified and evaluated. For Z. jujuba woodland, MWC < 9.2% and MWC>21.5% resulted in low productivity and medium WUE, 19.8–21.5% of MWC resulted in medium productivity and low WUE, 9.2–11.2% of MWC resulted in medium productivity and medium WUE, and 11.2–19.8% of MWC resulted in high productivity and high WUE. The optimum high productivity and high WUE of MWC were at 17.6%, and the corresponding optimum PAR was 1209 μmol m ⁻ ² s ⁻ ¹.
A series of new polyploid grape cultivars were bred using the strategy which combines traditional cross breeding with chemical-induced variation. In this strategy, germinated diploid hybrid grape ...seeds were treated with colchicine 0.6% at 25°C during the day and 20°C during the night for 48-72 h then planted in the field. The treated hybrid seedlings were first examined morphologically and then analyzed by tip-end slicing to verify the ploidy structure of the meristematic cells from the LI and LII layers. Results from chromosome counting in root tips indicated that these descedants are 2n=4x=76 while their parents are 2n=2x=38. Based on the size and shape of pollen and stomata, the number of chloroplasts in guard cells, it was concluded that these grape cultivars are tetraploids. Three tetraploid cultivars named ‘Zaoheibao’, ‘Qiuheibao’ and ‘Wanheibao’ were generated using this strategy, maturing at early-season of August, late-season of August and late-season of September, all have black purple in color, ‘Muscat’ flavor, good adaptability to environment and high disease-resistance.
PDF
