Smooth Action Research Articles

Influence of cartilage interstitial fluid on the mRNA levels of matrix proteins, cytokines, metalloproteases and their inhibitors in synovial membrane

Articular cartilage and the synovial membrane both ensure the smooth action of synovial joints; however, the influence of chondrocytes on synovial metabolism remains unclear. The secretory activity of chondrocytes is usually studied in cell cultures and may differ from that in intact cartilage. According to McCutchen's theory of 'weeping' joint lubrication, loading of the articular cartilage during motion squeezes the fluid with lubricating properties from the cartilage. The purpose of the study was to obtain cartilage interstitial fluid(CIF) from intact cartilage and to evaluate its influence on gene expression in the synovial membrane cells. CIF was rinsed out from the cartilage of newborn rats at a pressure of three bar. The chondrocytes survived rinsing and grew in culture. Cytokines in CIF were detected using the enzyme-linked immunosorbent assay(ELISA). The influence of CIF and CIF-like cocktail (all cytokines found in CIF) on gene expression in the synovial membrane cells was studied after a 4h-incubation, by real-time PCR. Data were analyzed using the Wilcoxon matched-pair test or by the Mann‑Whitney Utest. CIF contained basic fibroblast growth factor(bFGF), insulin-like growth factor(IGF)‑1, transforming growth factorβ1(TGFβ1), bone morphogenetic protein7(BMP7), macrophage(M)-colony-stimulating factor(CSF), granulocyte(G)-CSF and leukemia inhibitory factor(LIF). CIF stimulated the expression of hyaluronan synthase(HAS)1and2, lubricin, collagenI, versican, aggrecan, matrix metalloproteinases(MMPs)2and3, tissue inhibitors of metalloproteinases(TIMPs)1-3, interleukin(IL)-6 and TGFβ1, and decreased the expression of tumor necrosis factor(TNF) and IL-1β. Incubation of the synovial membrane with CIF-like cocktail partially imitated the effects of CIF. Analysis of CIF composition may help to characterize the secretory activity of chondrocytes in their natural environment under various physiological and pathological conditions and to understand the interactions between articular cartilage and the synovial membrane.

Abelian actions with globally hypoelliptic leafwise Laplacian and rigidity

In this paper, we prove several results concerning smooth Rk actions on a smooth compact manifold with the property that their leafwise Laplacian is globally hypoelliptic. Such actions are necessar ...

Infinitesimal Actions of $$\mathbf {R}^2$$ R 2 Around Isolated Fixed Points in the Plane

We study infinitesimal smooth actions of $$\mathbf {R}^2$$ (pairs of commuting vector fields) in the neighborhood of a fixed point on a surface, with special emphasis on the case where the action is tangent to the identity and the fixed point surrounded by an orbit of dimension two. We give conditions guaranteeing the topological and smooth equivalence of such actions.

NONAXISYMMETRIC MHD INSTABILITIES OF CHANDRASEKHAR STATES IN TAYLOR-COUETTE GEOMETRY

ABSTRACT We consider axially periodic Taylor–Couette geometry with insulating boundary conditions. The imposed basic states are so-called Chandrasekhar states, where the azimuthal flow U ϕ and magnetic field B ϕ have the same radial profiles. Mainly three particular profiles are considered: the Rayleigh limit, quasi-Keplerian, and solid-body rotation. In each case we begin by computing linear instability curves and their dependence on the magnetic Prandtl number . For the azimuthal wavenumber m = 1 modes, the instability curves always scale with the Reynolds number and the Hartmann number. For sufficiently small these modes therefore only become unstable for magnetic Mach numbers less than unity, and are thus not relevant for most astrophysical applications. However, modes with can behave very differently. For sufficiently flat profiles, they scale with the magnetic Reynolds number and the Lundquist number, thereby allowing instability also for the large magnetic Mach numbers of astrophysical objects. We further compute fully nonlinear, three-dimensional equilibration of these instabilities, and investigate how the energy is distributed among the azimuthal (m) and axial (k) wavenumbers. In comparison spectra become steeper for large m, reflecting the smoothing action of shear. On the other hand kinetic and magnetic energy spectra exhibit similar behavior: if several azimuthal modes are already linearly unstable they are relatively flat, but for the rigidly rotating case where m = 1 is the only unstable mode they are so steep that neither Kolmogorov nor Iroshnikov–Kraichnan spectra fit the results. The total magnetic energy exceeds the kinetic energy only for large magnetic Reynolds numbers .

A note on actions of some monoids

Smooth actions of the multiplicative monoid (R,⋅) of real numbers on manifolds lead to an alternative, and for some reasons simpler, definitions of a vector bundle, a double vector bundle and related structures like a graded bundle (Grabowski and Rotkiewicz (2011) [10]). For these reasons it is natural to study smooth actions of certain monoids closely related with the monoid (R,⋅). Namely, we discuss geometric structures naturally related with: smooth and holomorphic actions of the monoid of multiplicative complex numbers, smooth actions of the monoid of second jets of punctured maps (R,0)→(R,0), smooth actions of the monoid of real 2 by 2 matrices and smooth actions of the multiplicative reals on a supermanifold. In particular cases we recover the notions of a holomorphic vector bundle, a complex vector bundle and a non-negatively graded manifold.

Planning my actions to accommodate yours: joint action development during early childhood.

The planning and adjusting of one's actions in relation to an action partner is fundamental to smooth joint action. During their first years of life, children gradually become more engaged in joint actions. Here, we investigated whether and at what age children take their partner into account in their action plans to accommodate the other's actions. We focused on children's proactive planning (without prior experience) and flexible adjustment of action plans over time. In a behavioural study, we tested 96 children from four age groups (2½, 3, 3½ and 5 years) in a joint cup-stacking task. Children passed cups to their partner who had only one hand available (alternating over time) to build a tower. Children's response choices were assessed (i.e. passing the cup on the free or occupied side to their partner). The study yielded two major findings. At all ages, children proactively planned their actions in a way that accommodated their partner's actions. However, only by 3½ years did children start to flexibly integrate their partner into their action plans. Even at age 5, children only showed minimal adjustments to their action partner. Candidate processes underlying these developmental changes (e.g. inhibitory control, cognitive flexibility, perspective taking) are discussed.

Impact angle constrained guidance for all-aspect interception with function-based finite-time sliding mode control

In this paper, the impact angle constrained guidance problem, focusing on the nonlinear engagement dynamics, is considered. In order to fulfill the terminal constraints, a novel function-based finite-time sliding mode control methodology is introduced to design the guidance law. The main feature of this guidance law is that it achieves the desired impact angle exactly at the time of interception. In addition, it is capable of ensuring a continuous and smooth control action. To improve the tolerance of initial heading errors and broaden the application, a feasible guidance logic is also developed. Numerical simulations in various scenarios have shown that the proposed guidance scheme can realize all-aspect interception against stationary, constant-velocity and maneuvering targets. Furthermore, comparison studies with respect to nonsingular terminal sliding mode control-based methods demonstrate the superiority of the proposed method.

Arithmeticity and topology of smooth actions of higher rank abelian groups

We prove that any smooth action of $\mathbb{Z}^{m-1}$, $m\ge 3$, on an $m$-dimensional manifold that preserves a measure such that all non-identity elements of the suspension have positive entropy is essentially algebraic, i.e., isomorphic up to a finite permutation to an affine action on the torus or on its factor by $\pm\mathrm{Id}$. Furthermore this isomorphism has nice geometric properties; in particular, it is smooth in the sense of Whitney on a set whose complement has arbitrarily small measure. We further derive restrictions on topology of manifolds that may admit such actions, for example, excluding spheres and obtaining lower estimate on the first Betti number in the odd-dimensional case.

ROOT SYSTEMS AND SYMMETRIES OF TORUS MANIFOLDS

We associate a root system to a finite set in a free abelian group and prove that its irreducible subsystem is of type A, B or D. We apply this general result to a torus manifold, where a torus manifold is a $2n$-dimensional connected closed smooth manifold with a smooth effective action of an $n$-dimensional compact torus having a fixed point, and show that if the torus action extends to a smooth action of a connected compact Lie group $G$, then a simple factor of the Lie algebra of $G$ is of type A, B or D. This gives an alternative proof to Wiemeler's theorem. We also discuss a similar problem for a torus manifold with an invariant stably complex structure. In this case only type A appears.

Hyperbolic rotations about links in 3-manifolds

In this paper, we will show that for any link L in a closed orientable 3-manifold M, infinitely many hyperbolic 3-manifolds are obtained from M by Dehn surgeries so that each of them admits an orientation-preserving smooth finite cyclic group action with fixed point set L.

Stabilization of alternative current voltage

Two ways to construct a pulse ac voltage stabilizer (PACVS) are discussed in the present paper. In the first one, the acting, average, and amplitude voltages are controlled. An observation interval equal to or a multiple of half of the period of measured voltage is required for it. In the second variant, the instant values of the ac voltages are controlled, which allows one to correct the voltage from and compensate for the short voltage jumps and drops. It is shown that PACVS construction using a booster circuit decreases the demands made on the voltage of transistors and filter capacitor, in addition to impairing the quality of the stabilization and correction of the voltage form. Since it uses the feedback principle of the output voltage form, it is appropriate to construct the PACVS by means of the control principle over disturbance. This enables one to increase the stabilizer speed, since it responds directly to the source of the change in the output voltage rather than the consequence. It is shown that the smoothing action depends on the capacitor capacity and throttle inductance product, while the output resistance and the filter oscillation decrease with increasing capacity and decreasing inductance. An example of a PACVS controlling the instant values of the output voltage and the results of its investigation in MATLAB and Simulink are given.

NON JORDAN GROUPS OF DIFFEOMORPHISMS AND ACTIONS OF COMPACT LIE GROUPS ON MANIFOLDS

A recent preprint of Csikos, Pyber and Szabo [CPS] proves that the diffeomorphism group of T2 × S2 is not Jordan. The purpose of this paper is to generalize the arguments in [CPS] in order to obtain many other examples of compact manifolds whose diffeomorphism group fails to be Jordan. In particular we prove that for any ∈ > 0 there exist compact manifolds admitting effective smooth actions of arbitrarily large finite groups Γ all of whose abelian subgroups have at most |Γ|∈ elements. Finally, we also recover some results on the nonexistence of effective actions of compact connected semisimple Lie groups on manifolds.

Extending smooth cyclic group actions on the Poincaré homology sphere

Let $X_0$ denote a compact, simply-connected smooth $4$-manifold with boundary the Poincar\'e homology $3$-sphere $\Sigma(2,3,5)$ and with even negative definite intersection form $Q_{X_0}=E_8$. We show that free $\mathbb{Z}/p$ actions on $\Sigma(2,3,5)$ do not extend to smooth actions on $X_0$ with isolated fixed points for any prime $p>7$. The approach is to study the equivariant version of the Yang-Mills instanton-one moduli space for $4$-manifolds with cylindrical ends. As an application we show that for $p>7$ a smooth $\mathbb{Z}/p$ action on $\#^8 S^2 \times S^2$ with isolated fixed points does not split along a free action on $\Sigma(2,3,5)$. The results hold for $p=7$ if the action is homologically trivial.

The dual function of Cu-doped TiO2 coatings on titanium for application in percutaneous implants.

To endow percutaneous implants with improved skin integration and antibacterial activity, microporous TiO2 coatings doped with different doses of Cu2+ (0-1.93 wt%) were directly fabricated on Ti via micro-arc oxidation (MAO). The structures of coatings were investigated; the adhesion, proliferation, phenotype, differentiation and extracellular collagen secretion of fibroblasts, as well as the response of Staphylococcus aureus (S. aureus), were also investigated. The obtained results show that microporous TiO2 coatings all consist of antase and rutile, and incorporation of Cu2+ almost does not alter the phase component, surface roughness and topography of coating. Cu2+ facilitates the fibroblasts to switch to fibrotic phenotype and differentiate to myofibroblasts by enhancing the production of intracellular specific protein contents (connective tissue growth factor (CTGF) and alpha smooth muscle action (α-SMA)). Compared to Ti, the adhesion and proliferation of fibroblasts can be significantly enhanced on the TiO2 coating with 0.67 wt% Cu, while greatly inhibited with 1.93 wt% Cu. The difference should be due to the compromise between the positive effectiveness and the cytotoxicity of Cu2+. Cu2+-doped TiO2 coatings show good antibacterial properties, including contact-killing and release-killing of S. aureus, and these properties are positively related to the dose of Cu2+ in the coatings.

Review of renal anastomosing hemangioma with focus on clinical and pathological aspects.

Renal anastomosing hemangiomas (RAH) has been recently proposed as a new entity. In this article, we summarize the clinicopathologic features of this tumor. RAH usually develops on a background of end-stage renal disease. Macroscopically, tumors are well-defined and their cut surface shows mahogany brown spongy tissue with epicenter in the renal medulla. Tumors are usually small, but larger lesions are reported. On microscopic examination, the tumor consists of sinusoid-like vascular channels lined by cuboidal endothelial cells with occasional hobnail-like appearance of endothelial cells closely mimicking splenic sinusoids. Eosinophilic hyaline globules may be present in the cytoplasm of neoplastic endothelial cells. Extramedullary hematopoiesis containing erythroid precursor and megakaryocytes may be present in the vascular lumens. Immunohistochemically, endothelial cells are positive for CD31 and CD34, but negative for D2-40, GLUT-1 and HHV8. The surrounding stroma around endothelial cells demonstrates positivity for  smooth muscle action. To date, there are no studies on molecular genetic aspects of RAH. This tumor is indolent based on site and size of the lesion, partial or nephrectomy is sufficient as a therapeutic modality.

A note on the relation between joint and differential invariants

We discuss the general properties of the theory of joint invariants of a smooth Lie group action in a manifold. Many of the known results about differential invariants, including Lie’s finiteness theorem, have simpler versions in the context of joint invariants. We explore the relation between joint and differential invariants, and we expose a general method that allows to compute differential invariants from joint invariants.

Combining isoflurane anesthesia with midazolam and butorphanol in rats.

Representative inhalant anesthetic agent, isoflurane is commonly used during surgery in rats. However, isoflurane mediates relatively strong respiratory depression. In human and veterinary medicine, sedatives and analgesics are co-administered to complement the anesthetic action of inhalant anesthesia. The present study aimed to establish the novel balanced anesthesia that combines midazolam and butorphanol with isoflurane (MBI) in rats. Male Sprague Dawley rats were divided into 2 groups, and administered either isoflurane monoanesthesia or isoflurane with midazolam (2.5 mg/kg, ip) and butorphanol (2.0 mg/kg, ip). The minimum alveolar concentration (MAC) in each group was evaluated. Induction and recovery times were measured in each group. Adverse reactions during induction were also recorded. In each group, vital signs were assessed for 1 h under 1.5×MAC of isoflurane. Instability of vital signs was assessed under each anesthesia by calculating coefficient of variance. Compared with isoflurane monoanesthesia, MBI anesthesia caused 32% MAC reduction (isoflurane monoanesthesia: 1.30 ± 0.09%, MBI 0.87 ± 0.08%, P<0.05). MB premedication mediated smooth sedating action with low incidence of adverse reactions such as urination and defecation. Isoflurane monoanesthsesia remarkably decreased respiratory rate and saturation O2 (SPO2). In contrast, MBI anesthesia resulted in a relatively stable respiratory rate without decreases in SPO2 during the anesthetic period. In summary, MB premedication is effective for attenuating respiratory depression induced by isoflurane, and achieving smooth induction. This anesthetic protocol serves as a novel option for appropriate anesthesia in rats.

An uncountable family of pairwise non-Kakutani equivalent smooth diffeomorphisms

We construct on any smooth compact connected manifold of dimension greater than two on which there exists an effective smooth circle action preserving a positive smooth volume an uncountable family of smooth ergodic zero-entropy diffeomorphisms that are pairwise non-Kakutani equivalent. We first construct a smooth ergodic zero-entropy and non-loosely Bernoulli diffeomorphism by suitably modifying a smooth construction by Anosov and Katok.

Isovariant homotopy equivalences of manifolds with group actions

Let f f be an equivariant homotopy equivalence f f of connected closed manifolds with smooth semifree actions of a finite group G G , and assume also that f f is isovariant. The main result states that f f is a homotopy equivalence in the category of isovariant mappings if the manifolds satisfy a Codimension ≥ 3 \geq 3 Gap Hypothesis; this is done by showing directly that f f satisfies the criteria in the Isovariant Whitehead Theorem of G. Dula and the author. Examples are given to show the need for the hypotheses in the main result.

An averaging trick for smooth actions of compact quantum groups on manifolds

We prove that, given any smooth action of a compact quantum group (in the sense of [9]) on a compact smooth manifold satisfying some more natural conditions, one can get a Riemannian structure on the manifold for which the corresponding C∞(M)-valued inner product on the space of one-forms is preserved by the action.