14,510 research outputs found
Tunable photonic Bloch oscillations in electrically modulated photonic crystals
We exploit theoretically the occurrence and tunability of photonic Bloch
oscillations (PBOs) in one-dimensional photonic crystals (PCs) containing
nonlinear composites. Because of the enhanced third-order nonlinearity (Kerr
type nonlinearity) of composites, photons undergo oscillations inside tilted
photonic bands, which are achieved by the application of graded external pump
electric fields on such PCs, varying along the direction perpendicular to the
surface of layers. The tunability of PBOs (including amplitude and period) is
readily achieved by changing the field gradient. With an appropriate graded
pump AC or DC electric field, terahertz PBOs can appear and cover a terahertz
band in electromagnetic spectrum
Malignant phyllodes tumors display mesenchymal stem cell features and aldehyde dehydrogenase/disialoganglioside identify their tumor stem cells.
IntroductionAlthough breast phyllodes tumors are rare, there is no effective therapy other than surgery. Little is known about their tumor biology. A malignant phyllodes tumor contains heterologous stromal elements, and can transform into rhabdomyosarcoma, liposarcoma and osteosarcoma. These versatile properties prompted us to explore their possible relationship to mesenchymal stem cells (MSCs) and to search for the presence of cancer stem cells (CSCs) in phyllodes tumors.MethodsParaffin sections of malignant phyllodes tumors were examined for various markers by immunohistochemical staining. Xenografts of human primary phyllodes tumors were established by injecting freshly isolated tumor cells into the mammary fat pad of non-obese diabetic-severe combined immunodeficient (NOD-SCID) mice. To search for CSCs, xenografted tumor cells were sorted into various subpopulations by flow cytometry and examined for their in vitro mammosphere forming capacity, in vivo tumorigenicity in NOD-SCID mice and their ability to undergo differentiation.ResultsImmunohistochemical analysis revealed the expression of the following 10 markers: CD44, CD29, CD106, CD166, CD105, CD90, disialoganglioside (GD2), CD117, Aldehyde dehydrogenase 1 (ALDH), and Oct-4, and 7 clinically relevant markers (CD10, CD34, p53, p63, Ki-67, Bcl-2, vimentin, and Globo H) in all 51 malignant phyllodes tumors examined, albeit to different extents. Four xenografts were successfully established from human primary phyllodes tumors. In vitro, ALDH+ cells sorted from xenografts displayed approximately 10-fold greater mammosphere-forming capacity than ALDH- cells. GD2+ cells showed a 3.9-fold greater capacity than GD2- cells. ALDH+/GD2+cells displayed 12.8-fold greater mammosphere forming ability than ALDH-/GD2- cells. In vivo, the tumor-initiating frequency of ALDH+/GD2+ cells were up to 33-fold higher than that of ALDH+ cells, with as few as 50 ALDH+/GD2+ cells being sufficient for engraftment. Moreover, we provided the first evidence for the induction of ALDH+/GD2+ cells to differentiate into neural cells of various lineages, along with the observation of neural differentiation in clinical specimens and xenografts of malignant phyllodes tumors. ALDH+ or ALDH+/GD2+ cells could also be induced to differentiate into adipocytes, osteocytes or chondrocytes.ConclusionsOur findings revealed that malignant phyllodes tumors possessed many characteristics of MSC, and their CSCs were enriched in ALDH+ and ALDH+/GD2+ subpopulations
New Type of Soft (Prime) Ideals in Commutative BCK-Algebras
The soft set theory is an important mathematical tool for dealing with uncertainty. By endowing a par-ameter set as a commutative BCK-algebra (that is commutative weak-BCI-algebra), the notions of a new type of soft prime ideals, annihilators of soft sets and new type of involutory soft ideals in commutative BCK-algebras are introduced. Two new compositional operations are defined and used to characterize the new type of soft ideals in commutative BCK-algebras. By using partial ordering on commutative BCK-algebras, some properties of the new type of soft ideals are studied. Properties of annihilators of soft sets and new type of involutory soft ideals are obtained. The existence of a new type of soft prime ideals in commutative BCK-algebras and its difference from the standard soft prime ideals are illustrated with examples. It is shown that a soft set is a new type of soft prime ideals in commutative BCK-algebras and its level set is a prime ideal is not a necessary and sufficient condition, which is different from the results of the usual fuzzy algebra. Some equivalent characterizations of the new type of soft prime ideals in commutative BCK-algebras are given. Furthermore, the properties of its homomorphism image and inverse image are discussed
Structure and control of self-sustained target waves in excitable small-world networks
Small-world networks describe many important practical systems among which
neural networks consisting of excitable nodes are the most typical ones. In
this paper we study self-sustained oscillations of target waves in excitable
small-world networks. A novel dominant phase-advanced driving (DPAD) method,
which is generally applicable for analyzing all oscillatory complex networks
consisting of nonoscillatory nodes, is proposed to reveal the self-organized
structures supporting this type of oscillations. The DPAD method explicitly
explores the oscillation sources and wave propagation paths of the systems,
which are otherwise deeply hidden in the complicated patterns of randomly
distributed target groups. Based on the understanding of the self-organized
structure, the oscillatory patterns can be controlled with extremely high
efficiency.Comment: 16 pages 5 figure
Quantum switch for single-photon transport in a coupled superconducting transmission line resonator array
We propose and study an approach to realize quantum switch for single-photon
transport in a coupled superconducting transmission line resonator (TLR) array
with one controllable hopping interaction. We find that the single-photon with
arbitrary wavevector can transport in a controllable way in this system. We
also study how to realize controllable hopping interaction between two TLRs via
a superconducting quantum interference device (SQUID). When the frequency of
the SQUID is largely detuned from those of the two TLRs, the variables of the
SQUID can be adiabatically eliminated and thus a controllable interaction
between two TLRs can be obtained.Comment: 4 pages,3 figure
Expression and role of fibroblast activation protein-alpha in microinvasive breast carcinoma
<p>Abstract</p> <p>Background</p> <p>Diagnosis of ductal carcinoma in situ (DCIS) in breast cancer cases is challenging for pathologist due to a variety of in situ patterns and artefacts, which could be misinterpreted as stromal invasion. Microinvasion is detected by the presence of cytologically malignant cells outside the confines of the basement membrane and myoepithelium. When malignant cells invade the stroma, there is tissue remodeling induced by perturbed stromal-epithelial interactions. Carcinoma-associated fibroblasts (CAFs) are main cells in the microenvironment of the remodeled tumor-host interface. They are characterized by the expression of the specific fibroblast activation protein-alpha (FAP-α), and differ from that of normal fibroblasts exhibiting an immunophenotype of CD34. We hypothesized that staining for FAP-α may be helpful in determining whether DCIS has microinvasion.</p> <p>Methods</p> <p>349 excised breast specimens were immunostained for smooth muscle actin SMA, CD34, FAP-α, and Calponin. Study material was divided into 5 groups: group 1: normal mammary tissues of healthy women after plastic surgery; group 2: usual ductal hyperplasia (UDH); group 3: DCIS without microinvasion on H & E stain; group 4: DCIS with microinvasion on H & E stain (DCIS-MI), and group 5: invasive ductal carcinoma (IDC). A comparative evaluation of the four immunostains was conducted.</p> <p>Results</p> <p>Our results demonstrated that using FAP-α and Calponin adjunctively improved the sensitivity of pathological diagnosis of DCIS-MI by 11.29%, whereas the adjunctive use of FAP-α and Calponin improved the sensitivity of pathological diagnosis of DCIS by 13.6%.</p> <p>Conclusions</p> <p>This study provides the first evidence that immunostaining with FAP-α and Calponin can serve as a novel marker for pathologically diagnosing whether DCIS has microinvasion.</p
Deep Dimension Reduction for Supervised Representation Learning
The success of deep supervised learning depends on its automatic data
representation abilities. Among all the characteristics of an ideal
representation for high-dimensional complex data, information preservation, low
dimensionality and disentanglement are the most essential ones. In this work,
we propose a deep dimension reduction (DDR) approach to achieving a good data
representation with these characteristics for supervised learning. At the
population level, we formulate the ideal representation learning task as
finding a nonlinear dimension reduction map that minimizes the sum of losses
characterizing conditional independence and disentanglement. We estimate the
target map at the sample level nonparametrically with deep neural networks. We
derive a bound on the excess risk of the deep nonparametric estimator. The
proposed method is validated via comprehensive numerical experiments and real
data analysis in the context of regression and classification
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