Trifocal Relative Pose From Lines at Points.

We present a method for solving two minimal problems for relative camera pose estimation from three views, which are based on three view correspondences of (i) three points and one line and the novel case of (ii) three points and two lines through two of the points. These problems are too difficult to be efficiently solved by the state of the art Gröbner basis methods. Our method is based on a new efficient homotopy continuation (HC) solver framework MINUS, which dramatically speeds up previous HC solving by specializing hc methods to generic cases of our problems. We characterize their number of solutions and show with simulated experiments that our solvers are numerically robust and stable under image noise, a key contribution given the borderline intractable degree of nonlinearity of trinocular constraints. We show in real experiments that (i) sift feature location and orientation provide good enough point-and-line correspondences for three-view reconstruction and (ii) that we can solve difficult cases with too few or too noisy tentative matches, where the state of the art structure from motion initialization fails.

Biological information analysis of differentially expressed genes in oral squamous cell carcinoma tissues in GEO database.

PURPOSE: This study aimed to detect the differentially expressed genes between oral squamous cell carcinoma (OSCC) tissues and adjacent normal tissues, and perform pathway analysis and protein-protein interaction (PPI) analysis on differentially expressed genes (DEGs). METHODS: Gene Expression Omnibus (GEO) database related to human tumors was selected from the National Center for Biotechnology Information (NCBI), and GSE31056 and GSE3524, two microarrays containing OSCC gene expression data, were extracted from it. Analysis of differentially expressed genes in the two microarrays was performed using "R" software, and the volcanic map was drawn. Then, Venn diagram was used to integrate the differentially expressed genes screened out by the two microarrays, and PPI [Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG)] analysis of DEGs after integration was performed using Cytoscape, DAVID, STRING and KOBAS. A total of 207 differentially expressed genes were screened out by the two microarrays. 103 proteins encoded by differentially expressed genes screened out by STRING software had interaction. The expression network of differentially expressed genes was constructed, and some proteins, closely related to other proteins such as STAT1, were screened out by Cytoscape software. RESULTS: GO analysis and KEGG analysis found that the differentially expressed genes were mainly enriched in "extracellular region", "extracellular region part" and "membrane-bound vesicle", and mainly involved in biological processes such as "Amoebiasis", "Glycerolipid metabolism" and "Arachidonic acid metabolism". In this study, 207 differentially expressed genes were successfully screened out from the two OSCC microarrays. PPI, GO and KEGG pathways of 103 interacting proteins were successfully constructed. Key genes were screened out, annotation and pathway analysis of which were performed. CONCLUSION: This study was helpful to further study the relationship between OSCC gene directions.

Effect of lubricant on the reliability of dental implant abutment screw joint: An in vitro laboratory and three-dimension finite element analysis.

Biomechanical factors play a key role in the success of dental implants. Fracture and loosening of abutment screws are major issues. This study investigated the effect of lubricants on the stability of dental implant-abutment connection. As lubricants, graphite and vaseline were coated on the abutment screw surface, respectively, and a blank without lubricant served as the control. The total friction coefficient (µtot), clamping force, fatigue behavior and detorque of the joint combined with dynamic cyclic loading were measured under different lubricating conditions. Further, a three-dimensional finite element analysis was used to investigate stress distribution, in conjunction with experimental images. The results showed that the lubricant reduced µtot, which in turn led to an increase in clamping force. Decrease in loading increased the fatigue life of the screw. However, use of lubricant at high load reduced the fatigue life. Ductile fracture at the first thread of the screw was the chief failure mode, which was due to maximum von Mises stress. Higher stress levels occurred in the lubricant groups. Lubricated screws resulted in lower detorque which made the joint easier to loosen. In conclusion, the lubricant cannot effectively improve the reliability of dental implant-abutment connection. Keeping the interfaces of implant-screw uncontaminated and strengthening the surface of the screw may be recommend for clinical operation and future design.

Simple, Selective and Sensitive Determination of CH3Hg⁺ Using Gold Nanocluster.

Mercury is a potent neurotoxin, which causes serious and permanent damage to biota including human beings. Nanomaterials like gold have been used to detect mercury, especially the mercuric ions in recent years, but few have been done on the determination of methylmercury (CH3Hg⁺). In this study, we present a simple, selective and sensitive method for the determination of CH3Hg⁺ co-existing with Hg²âº based on the fluorescence quenching of bovine serum albumin (BSA) stabilized gold nanoclusters (BSA-Au NCs). It was found that the fluorescence quenching of BSA-Au NCs by Hg²âº is stronger than CH3Hg⁺ at the same concentration. Hg²âº can be masked by EDTA while CH3Hg⁺ is less affected. Therefore, the determination of CH3Hg⁺ was achieved through EDTA masking. The detection limit for CH3Hg⁺ is 35 nmol/L after masking Hg²âº with EDTA. This method has been successfully applied to quantify CH3Hg⁺ in rice paddy water from Qingzhen, Guizhou and tap water from Beijing.

Mechanical stretch endows mesenchymal stem cells stronger angiogenic and anti-apoptotic capacities via NFκB activation.

Mesenchymal stem cells (MSCs) have been broadly used for tissue regeneration and repair due to their broad differentiation potential and potent paracrine properties such as angiogenic capacity. Strategies to increase their survival rate after transplantation and the angiogenic ability are of priority for the utility of MSCs. In this study, we found that mechanical stretch (10% extension, 30 cycles/min cyclic stretch) preconditioning increase the angiogenic capacity via VEGFA induction. In addition, mechanical stretch also increases the survival rate of mesenchymal stem cells under nutrients deprivation. Consistent with the increase VEGFA expression and resistance to apoptosis, nuclear localization of NFκB activity p65 increased upon mechanical stretch. Inhibition of NFκB activity by BAY 11-708 blocks the pro-angiogenesis and anti-apoptosis function of mechanical stretch. Taken together, our findings here raise the possibility that mechanical stretch preconditioning might enhance the therapeutic efficacy of mesenchymal stem cells.

Involvement of PI3K/Akt pathway in rat condylar chondrocytes regulated by PTHrP treatment.

OBJECTIVE: The aim of this study was to explore the mutual communication of the parathyroid hormone-related peptide (PTHrP) and phosphatidylinositol 3-kinase/threonine protein kinase (PI3K/Akt) pathway on the proliferation and differentiation of condylar chondrocytes from Sprague-Dawley (SD) rats. METHODS: Condylar chondrocytes from the condylar cartilage were cultured and an organ culture system of mandibular condyles was employed. The distribution of PI3K, phospho-Akt (p-Akt), and PTHrP in condylar cartilage was detected by either immunohistochemistry or immunofluorescence. The second passage chondrocytes and condyle specimens in the organ culture system were treated with PTHrP, LY294002, PTHrP and LY294002 in combination, or dimethyl sulfoxide (DMSO), separately. The mRNA and protein levels of type II (Col II) and type X collagen (Col X) were investigated by real-time polymerase chain reaction (PCR) and Western blot analysis. The condyle growth in organ culture system was analysed by haematoxylin-eosin staining. RESULTS: PTHrP, PI3K, and p-Akt were mainly located in the proliferative and hypertrophic zones. PTHrP promoted the proliferation of condylar chondrocytes, while LY294002 limited this effect. The mRNA and protein levels of Col II and Col X in these cells were reduced by PTHrP and enhanced by LY294002. Organ culture showed a significant enhancement of condyle elongation with PTHrP treatment or a combination of PTHrP and LY294002 treatment. After treatment with LY294002, the length of condyles was reduced compared with the samples treated with DMSO. CONCLUSIONS: We conclude that the PI3K/Akt pathway plays an essential role in the proliferation and differentiation of condylar chondrocytes and is a potential target for PTHrP in regulating chondrocyte differentiation at condylar cartilage.

New complex integration transformation and its compatibility with complex Weyl-Wigner transformation and entangled state representation.

Enlightened by the special transformation in our preceding paper [J. Mod. Opt. 56, 1227 (2009)], we propose a new complex integration transformation corresponding to two mutually conjugate two-mode entangled states

Symplectic-dilation mixed wavelet transform and its correspondence in quantum optics.

The symplectic wavelet transform, which is related to the quantum optical Fresnel transform, is developed to the symplectic-dilation mixed wavelet transform (SDWT). The SDWT involves both a real-variable dilation-transform and a complex-variable symplectic transform and possesses well-behaved properties such as the Parseval theorem and the inversion formula. The entangled-coherent state representation not only underlies the SDWT but also helps to derive the corresponding quantum transform operator whose counterpart in classical optics is the lens-Fresnel mixed transform.

Eigenfunctions of the complex fractional Fourier transform obtained in the context of quantum optics.

We employ the recently established basis (the two-variable Hermite-Gaussian function) of the generalized Bargmann space (BGBS) [Phys. Lett. A303, 311 (2002)] to study the generalized form of the fractional Fourier transform (FRFT). By using the technique of integration within an ordered product of operators and the bipartite entangled-state representations, we derive the generalized generating function of the BGBS with which the undecomposable kernel of the two-dimensional FRFT [also named complex fractional Fourier transform (CFRFT)] is obtained. This approach naturally shows that the BGBS is just the eigenfunction of the CFRFT.

Two quantum-mechanical photocount formulas.

We derive two quantum-mechanical photocount formulas when a light field's density operator rho is known; one involves rho's coherent state mean value and the other involves rho's Wigner function; when this information is known, then using these two formulas to calculate the photocount would be convenient. We employ the technique of integration within an antinormally ordered (or Weyl-ordered) product of operators in our derivation.

Explicit state vector for Torres-Vega-Frederick phase space representation and its statistical behavior.

We find the explicit state vector for Torres-Vega-Frederick phase space representation [Go. Torres-Vega and J. H. Frederick, J. Chem. Phys. 98, 3103 (1993)], denoted by Gamma. This set of states make up a complete and nonorthogonal representation. The Weyl ordered form of Gamma Gamma [see text for the sign] is derived, which can clearly exhibit the statistical behavior of marginal distribution of Gamma Gamma [see text for the sign]. The minimum uncertainty relation for mid R:Gamma is demonstrated, which shows it being a coherent squeezed state.

Entangled symplectic wavelet transformation.

The symplectic wavelet transformation proposed in Opt. Lett. 31, 3432 (2006), which is related to the optical Fresnel transform in the quantum optics version, is developed into an entangled symplectic wavelet transformation (ESWT) after pointing out the contrast between the single-mode Fresnel operator and the entangled Fresnel operator. The ESWT possesses well-behaved properties and corresponds to the entangled Fresnel transform [Phys. Lett. A334, 132 (2005)].

Mother wavelets for complex wavelet transform derived by Einstein-Podolsky-Rosen entangled state representation.

The Einstein-Podolsky-Rosen entangled state representation is applied to studying the admissibility condition of mother wavelets for complex wavelet transforms, which leads to a family of new mother wavelets. Mother wavelets thus are classified as the Hermite-Gaussian type for real wavelet transforms and the Laguerre-Gaussian type for the complex case.

Symplectic wavelet transformation.

Usually a wavelet transform is based on dilated-translated wavelets. We propose a symplectic-transformed-translated wavelet family psi(*)(r,s)(z-kappa) (r,s are the symplectic transform parameters, |s|(2)-|r|(2)=1, kappa is a translation parameter) generated from the mother wavelet psi and the corresponding wavelet transformation W(psi)f(r,s;kappa)=integral(infinity)(-infinity)(d(2)z/pi)f(z)psi(*)(r,s)(z-kappa). This new transform possesses well-behaved properties and is related to the optical Fresnel transform in quantum mechanical version.

Collins diffraction formula studied in quantum optics.

We find that the Collins diffraction formula in cylindrical coordinates is just the transformation matrix element of a three-parameter two-mode squeezing operator in the deduced entangled state representation. This is a new tie connecting the unitary transform in quantum optics to the generalized Hankel transform in Fourier optics. The group multiplication rule of the squeezing operators maps to the Collins formula related to two successive Hankel transforms.

General formula for finding mother wavelets by virtue of Dirac's representation theory and the coherent state.

The admissibility condition of a mother wavelet is explored in the context of quantum optics theory. By virtue of Dirac's representation theory and the coherent state property we derive a general formula for finding qualified mother wavelets. A comparison between a wavelet transform computed with the newly found mother wavelet and one computed with a Mexican hat wavelet is presented.

Talbot effect in a quadratic-index medium studied with two-variable Hermite polynomials and entangled states.

We have found the new eigenmodes, two-variable Hermite polynomials, exist in propagating plane waves in quadratic-index media and that a two-dimensional Talbot effect can be demonstrated with these modes.

Fractional Hankel transform studied by charge-amplitude state representations and complex fractional Fourier transformation.

Starting from a complex fractional Fourier transformation [Opt. Lett. 28, 680 (2003)], it is shown that the integral kernel of a fractional Hankel transformation is equivalent to the matrix element of an appropriate operator in the charge-amplitude state representations; i.e., the fractional Hankel transformation is endowed with a definite physical meaning (definite quantum-mechanical representation transform).

Eigenmodes of fractional Hankel transform derived by the entangled-state method.

Using the entangled-state method in quantum mechanics, we find that the eigenmodes of the fractional Hankel transform are two-variable Hermite-Gaussian functions that can be rewritten in a clearer form as Laguerre polynominals.