1,630 research outputs found
Using optimized random amplified polymorphic DNA (RAPD) markers to identify the category status of Citrus nobilis Lour. Gonggan
Citrus nobilis Lour. Gonggan is an excellent fruit variety which is widely planted in South China. The origin of Gonggan is not clear. It is conjectured that its origin is from a cross between tangerine and orange; however, there is no direct evidence to confirm this. Here, we applied the optimized random amplified polymorphic DNA (RAPD)-PCR to amplify genus Citrus species: 1) to better understand the genetic relationship between C. nobilis Lour. Gonggan and other Citrus species; and (2) to address the phylogenetic relationship among Citrus species. A total of 21 RAPD primers were used to screen 4 Citrus species and 10 of them efficiently amplified the genomic DNA of 23 Citrus accessions. A total of 87 locus/alleles were generated by those 10 primers with an average of 97.7% polymorphic. Our data supported that C. nobilis Lour. Gonggan belongs to a big group with most tested tangerine and orange and a subgroup with Citrus haniana and Citrus flamea, implying that either C. haniana or C. flamea is likely to be one of the parents of C. nobilis Lour. Gonggan.Key words: Citrus nobilis Lour. Gonggan, random amplified polymorphism DNA (RAPD), phylogeneticrelationshi
Priming of Toll-like receptor 4 pathway in mesenchymal stem cells increases expression of B cell activating factor
AbstractMesenchymal stem cells (MSCs) can be polarized into two distinct populations, MSC1 and MSC2, by activation of different Toll-like receptors (TLRs). TLR4-primed MSC1 expressed proinflammatory factors, whereas TLR3-primed MSC2 expressed suppressive factors. However, little is known about the function of TLRs on B lymphocyte-related immune modulation. In this study, we investigated the expression of B cell activating factor (BAFF), a member of the tumor necrosis factor ligand superfamily with notable stimulating activity on B cells, in human MSCs (hMSCs) and in murine MSCs (mMSCs) after activation of TLRs. BAFF was increasingly expressed in presence of TLR4 agonist (lipopolysaccharide, LPS), while TLR2 agonist (Zymosan) and TLR3-agonist (polyinocinic–polycytidykic acid, poly I:C) had no effect on BAFF expression. In addition, we demonstrated that signaling pathways of NF-κB, p38 MAPK, and JNK were involved in TLR4-primed BAFF expression. Our results suggested that TLR4 and downstream pathways in MSCs exert an important function in B lymphocyte-related immune regulation. Further defining a homogeneous population of MSCs should provide insight into MSC-based immune-modulating therapy
The content and ratio of type I and III collagen in skin differ with age and injury
The aim of this study is to examine type I and III collagen content and distribution in skin within the contexts of patient age and injury, as well as to elucidate possible mechanisms of hypertrophic scar formation. Normal human skin and hypertrophic scar specimens were obtained from spontaneously aborted fetuses and burn patients of different ages (adolescent group, ≤18 years; adult group, >19 and ≤50 years; elderly group, >50 years). Total collagen content was indirectly determined by quantification of hydroxyproline. Levels of type I and III collagen as well as the ratio of type I/III were determined by immunohistochemistry and image analysis. Results obtained showed that the mean content of type I and III and type I/III ratio in normal skin differed significantly among age groups (P0.05), with the lowest levels of type I, III, and the highest ratio of type I/III observed in the elderly age group. Differences between normal uninjured skin and hypertrophic scar tissue were significant for all investigated parameters within any of the three age groups examined (adolescent, adult, elderly; P<0.05). Content of type I, III collagen and type I/III ratio also exhibited age-dependent differences during recovery in hypertrophic scar specimens. Thus, type III collagen synthesis decreases with age resulting in a skewed type I/III ratio and changes in skin tension, elasticity, and healing. Also, the content of type I, III collagen and type I/III ratio are significantly altered in hypertrophic scar tissue compared to uninjured age-matched controls, resulting in a different structural organization that is also influenced by patient age.Key words: Age group, hypertrophic scar, collagen type I, collagen type III, immunohistochemistry, hydroxyproline
Factorization and Lie point symmetries of general Lienard-type equation in the complex plane
We present a variational approach to a general Lienard-type equation in order
to linearize it and, as an example, the Van der Pol oscillator is discussed.
The new equation which is almost linear is factorized. The point symmetries of
the deformed equation are also discussed and the two-dimensional Lie algebraic
generators are obtained
Coulomb effects on the formation of proton halo nuclei
The exotic structures in the 2s_{1/2} states of five pairs of mirror nuclei
^{17}O-^{17}F, ^{26}Na-^{26}P, ^{27}Mg-^{27}P, ^{28}Al-^{28}P and
^{29}Si-^{29}P are investigated with the relativistic mean-field (RMF) theory
and the single-particle model (SPM) to explore the role of the Coulomb effects
on the proton halo formation. The present RMF calculations show that the exotic
structure of the valence proton is more obvious than that of the valence
neutron of its mirror nucleus, the difference of exotic size between each
mirror nuclei becomes smaller with the increase of mass number A of the mirror
nuclei and the ratios of the valence proton and valence neutron
root-mean-square (RMS) radius to the matter radius in each pair of mirror
nuclei all decrease linearly with the increase of A. In order to interpret
these results, we analyze two opposite effects of Coulomb interaction on the
exotic structure formation with SPM and find that the contribution of the
energy level shift is more important than that of the Coulomb barrier for light
nuclei. However, the hindrance of the Coulomb barrier becomes more obvious with
the increase of A. When A is larger than 34, Coulomb effects on the exotic
structure formation will almost become zero because its two effects counteract
with each other.Comment: 9 pages, 6 figures. One colum
Knotting probabilities after a local strand passage in unknotted self-avoiding polygons
We investigate the knotting probability after a local strand passage is
performed in an unknotted self-avoiding polygon on the simple cubic lattice. We
assume that two polygon segments have already been brought close together for
the purpose of performing a strand passage, and model this using Theta-SAPs,
polygons that contain the pattern Theta at a fixed location. It is proved that
the number of n-edge Theta-SAPs grows exponentially (with n) at the same rate
as the total number of n-edge unknotted self-avoiding polygons, and that the
same holds for subsets of n-edge Theta-SAPs that yield a specific
after-strand-passage knot-type. Thus the probability of a given
after-strand-passage knot-type does not grow (or decay) exponentially with n,
and we conjecture that instead it approaches a knot-type dependent amplitude
ratio lying strictly between 0 and 1. This is supported by critical exponent
estimates obtained from a new maximum likelihood method for Theta-SAPs that are
generated by a composite (aka multiple) Markov Chain Monte Carlo BFACF
algorithm. We also give strong numerical evidence that the after-strand-passage
knotting probability depends on the local structure around the strand passage
site. Considering both the local structure and the crossing-sign at the strand
passage site, we observe that the more "compact" the local structure, the less
likely the after-strand-passage polygon is to be knotted. This trend is
consistent with results from other strand-passage models, however, we are the
first to note the influence of the crossing-sign information. Two measures of
"compactness" are used: the size of a smallest polygon that contains the
structure and the structure's "opening" angle. The opening angle definition is
consistent with one that is measurable from single molecule DNA experiments.Comment: 31 pages, 12 figures, submitted to Journal of Physics
Novel semi-supervised classification method based on class certainty of samples
The traditional classification method based on supervised learning classifies remote sensing (RS) images by using sufficient labeled samples. However, the number of labeled samples is limited due to the expensive and time-consuming collection. To effectively utilize the information of unlabeled samples in the learning process, this paper proposes a novel semi-supervised classification method based on class certainty of samples (CCS). First, the class certainty of unlabeled samples obtained based on multi-class SVM is smoothed for robustness. Then, a new semi-supervised linear discriminant analysis (LDA) is presented based on class certainty, which improves the separability of samples in the projection subspace. Ultimately, we extend the semi-supervised LDA to nonlinear dimensional reduction by combining class certainty and kernel methods. Furthermore, to assess the effectiveness of proposed method, the nearest neighbor classifier is adopted to classify actual SAR images. The results demonstrate that the proposed method can effectively exploit the information of unlabeled samples and greatly improve the classification effect compared with other state-of-the-art approaches
When things matter: A survey on data-centric Internet of Things
With the recent advances in radio-frequency identification (RFID), low-cost wireless sensor devices, and Web technologies, the Internet of Things (IoT) approach has gained momentum in connecting everyday objects to the Internet and facilitating machine-to-human and machine-to-machine communication with the physical world. IoT offers the capability to connect and integrate both digital and physical entities, enabling a whole new class of applications and services, but several significant challenges need to be addressed before these applications and services can be fully realized. A fundamental challenge centers around managing IoT data, typically produced in dynamic and volatile environments, which is not only extremely large in scale and volume, but also noisy and continuous. This paper reviews the main techniques and state-of-the-art research efforts in IoT from data-centric perspectives, including data stream processing, data storage models, complex event processing, and searching in IoT. Open research issues for IoT data management are also discussed
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