Liver X Receptor activation delays chondrocyte hypertrophy during endochondral bone growth

Objective: Activation of the Liver X Receptor (LXR) has recently been identified as a therapeutic strategy for osteoarthritis (OA). Human OA articular cartilage explants show decreased LXR expression, and LXRβ-null mice display OA-like symptoms. LXR agonist administration to OA articular cartilage explants suppresses proteoglycan degradation and restores LXR-activated transcription. We aimed to investigate the effect of LXR activation on chondrocyte differentiation to elucidate the molecular mechanisms behind its protection against OA. Method: The specific LXR agonist, GW3965, was used to examine the effect of LXR activation on chondrocyte differentiation. Tibia organ cultures were used to examine the effect of LXR activation on bone growth and growth plate morphology, followed by immunohistochemical analysis. In ATDC5 and micromass cultures, chondrocyte differentiation was examined through cellular staining and proliferation assays. Various chondrogenic markers were analyzed by real-time reverse-transcription polymerase chain reaction (qRT-PCR) in micromass RNA. Results: Chondrocyte hypertrophy was suppressed by GW3965 treatment, as shown by decreased hypertrophic zone length in the tibial growth plate, decreased alkaline phosphatase staining in ATDC5 and micromass cultures, and down regulation of Col10a1, Mmp13 and Runx2 expression. Increased proliferation in treated ATDC5 cells and up-regulation of Col2a1 expression in treated micromass cultures suggest hypertrophy is suppressed secondary to prolonged proliferation. Decreased p57 levels in treated growth plates suggest this to be due to cell-cycle exit delay. Conclusion: Our findings regarding LXR\u27s role in cartilage development provide insight into how LXR activation prevents cartilage breakdown, further solidifying its potential as a therapeutic target of OA. © 2014 Osteoarthritis Research Society International

Liver X Receptor activation delays chondrocyte hypertrophy during endochondral bone growth

Objective: Activation of the Liver X Receptor (LXR) has recently been identified as a therapeutic strategy for osteoarthritis (OA). Human OA articular cartilage explants show decreased LXR expression, and LXRβ-null mice display OA-like symptoms. LXR agonist administration to OA articular cartilage explants suppresses proteoglycan degradation and restores LXR-activated transcription. We aimed to investigate the effect of LXR activation on chondrocyte differentiation to elucidate the molecular mechanisms behind its protection against OA. Method: The specific LXR agonist, GW3965, was used to examine the effect of LXR activation on chondrocyte differentiation. Tibia organ cultures were used to examine the effect of LXR activation on bone growth and growth plate morphology, followed by immunohistochemical analysis. In ATDC5 and micromass cultures, chondrocyte differentiation was examined through cellular staining and proliferation assays. Various chondrogenic markers were analyzed by real-time reverse-transcription polymerase chain reaction (qRT-PCR) in micromass RNA. Results: Chondrocyte hypertrophy was suppressed by GW3965 treatment, as shown by decreased hypertrophic zone length in the tibial growth plate, decreased alkaline phosphatase staining in ATDC5 and micromass cultures, and down regulation of Col10a1, Mmp13 and Runx2 expression. Increased proliferation in treated ATDC5 cells and up-regulation of Col2a1 expression in treated micromass cultures suggest hypertrophy is suppressed secondary to prolonged proliferation. Decreased p57 levels in treated growth plates suggest this to be due to cell-cycle exit delay. Conclusion: Our findings regarding LXR\u27s role in cartilage development provide insight into how LXR activation prevents cartilage breakdown, further solidifying its potential as a therapeutic target of OA. © 2014 Osteoarthritis Research Society International

Reduction of the Three Dimensional Schrodinger Equation for Multilayered Films

In this paper, we present a method for reducing the three dimensional Schrodinger equation to study confined metallic states, such as quantum well states, in a multilayer film geometry. While discussing some approximations that are employed when dealing with the three dimensionality of the problem, we derive a one dimensional equation suitable for studying such states using an envelope function approach. Some applications to the Cu/Co multilayer system with regard to spin tunneling/rotations and angle resolved photoemission are discussed.Comment: 14 pages, 1 figur

Superradiance of low density Frenkel excitons in a crystal slab of three-level atoms: Quantum interference effect

We systematically study the fluorescence of low density Frenkel excitons in a crystal slab containing $N_T$ V-type three-level atoms. Based on symmetric quasi-spin realization of SU(3) in large $N$ limit, the two-mode exciton operators are invoked to depict various collective excitations of the collection of these V-type atoms starting from their ground state. By making use of the rotating wave approximation, the light intensity of radiation for the single lattice layer is investigated in detail. As a quantum coherence effect, the quantum beat phenomenon is discussed in detail for different initial excitonic states. We also test the above results analytically without the consideration of the rotating wave approximation and the self-interaction of radiance field is also included.Comment: 18pages, 17 figures. Resubmit to Phys. Rev.

Optimal quantum pump in the presence of a superconducting lead

We investigate the parametric pumping of a hybrid structure consisting of a normal quantum dot, a normal lead and a superconducting lead. Using the time dependent scattering matrix theory, we have derived a general expression for the pumped electric current and heat current. We have also derived the relationship among the instantaneous pumped heat current, electric current, and shot noise. This gives a lower bound for the pumped heat current in the hybrid system similar to that of the normal case obtained by Avron et al

Quantization of adiabatic pumped charge in the presence of superconducting lead

We investigate the parametric electron pumping of a double barrier structure in the presence of a superconducting lead. The parametric pumping is facilitated by cyclic variation of the barrier heights $x_1$ and $x_2$ of the barriers. In the weak coupling regime, there exists a resonance line in the parameter space $(x_1,x_2)$ so that the energy of the quasi-bound state is in line with the incoming Fermi energy. Levinson et al found recently that the pumped charge for each pumping cycle is quantized with $Q=2e$ for normal structure when the pumping contour encircles the resonance line. In the presence of a superconducting lead, we find that the pumped charge is quantized with the value $2e$

A slip-based model for the size-dependent effective thermal conductivity of nanowires

The heat flux across a nanowire is computed based on the Guyer-Krumhansl equation. Slip conditions with a slip length depending on both temperature and nanowire radius are introduced at the outer boundary. An explicit expression for the effective thermal conductivity is derived and compared to existing models across a given temperature range, providing excellent agreement with experimental data for Si nanowires

The effects of citrate dialysate in hemodialysis on polymorphonuclear elastase interaction with tissue factor and its inhibitor

Background: This study aimed to investigate whether hemodialysis (HD) affects tissue factor (TF), tissue factor pathway inhibitor (TFPI), and polymorphonuclear elastase (PMNE) in endstage renal disease (ESRD) patients when eliminating the effects of heparin. Also, to explore the interaction of TF, TFPI, and PMNE throughout a single HD session. Methods: We enrolled 57 ESRD patients who had undergone hemodialysis for >3 months as an experimental group. Plasma levels of TF, TFPI and PMNE were measured by ELISA in 24 ERSD patients on intermittent HD using low-molecular-weight heparin (LMWH) as anticoagulation (LMWH group) and 33 ESRD patients using citrate as anticoagulation (citrate group) at the start and at 1, 2 and 5 h of the HD session. Meanwhile,28 ESRD patients not on dialysis were enrolled as a control group and fasting venous blood samples were taken in the morning. Results: Compared with the control group, the plasma TFPI levels of the LMWH group and the citrate group were significantly higher (P=0.000, P=0.002, respectively) under baseline conditions as well as the plasma PMNE levels (P=0.001, P=0.02, respectively), whereas TF showed no difference (P=0.186). During HD with citrate, plasma TFPI decreased slightly (P=0.012) and PMNE increased significantly (P=0.008) at 1 h. The plasma TFPI levels of the citrate group correlate with PMNE at 2 and 5 h (P=0.001, P=0.008, respectively). Conclusions: ESRD patients on HD have significantly higher TFPI and PMNE levels compared to patients not on HD under baseline conditions, while TF levels were similar between the three groups. TFPI and PMNE are differently regulated, but the plasma levels correlated during HD in the citrate group. It might be possible that PMNE plays a role in anticoagulative activity through TFPI

Is Individualism Suicidogenic? Findings From a Multinational Study of Young Adults From 12 Countries

The associations of individualistic versus collectivistic value orientations with suicidal ideation and attempts, attitudes towards suicide and towards suicidal individuals, and psychological distress were investigated across 12 nations (N = 5572 university students). We expected differential associations of value orientations with suicidal behavior and moderating effects of the prevailing value orientations in the various countries. Findings showed that intermediate levels of individualism appeared protective against suicide attempts across all investigated nations, but that, otherwise, there seemingly are no universal associations of individualism and collectivism with suicidal behaviors. High collectivism was associated with less suicidal ideation only in individualistic countries. Low individualism appeared to be a risk factor for suicidal ideation specifically in Muslim collectivistic cultures, whereas high individualism in Asian collectivistic cultures. Collectivistic values are uniformly associated with less permissive attitudes to suicide, whereas individualistic values with a more stigmatized view of suicidal behavior. Both individualistic and collectivistic values were associated with socially accepting attitudes to a suicidal peer, helping a suicidal friend, and emotional involvement. The associations of individualistic and collectivistic values with disapproving attitudes to suicidal disclosure were complex. Beliefs in punishment after death for suicide, seeing suicide as mental illness, and emotional involvement with a suicidal friend were lower in high-suicide-rate countries. These evidence patterns are discussed in the light of related research evidence, along with directions for future research in this area

Security and Privacy Issues in Wireless Mesh Networks: A Survey

This book chapter identifies various security threats in wireless mesh network (WMN). Keeping in mind the critical requirement of security and user privacy in WMNs, this chapter provides a comprehensive overview of various possible attacks on different layers of the communication protocol stack for WMNs and their corresponding defense mechanisms. First, it identifies the security vulnerabilities in the physical, link, network, transport, application layers. Furthermore, various possible attacks on the key management protocols, user authentication and access control protocols, and user privacy preservation protocols are presented. After enumerating various possible attacks, the chapter provides a detailed discussion on various existing security mechanisms and protocols to defend against and wherever possible prevent the possible attacks. Comparative analyses are also presented on the security schemes with regards to the cryptographic schemes used, key management strategies deployed, use of any trusted third party, computation and communication overhead involved etc. The chapter then presents a brief discussion on various trust management approaches for WMNs since trust and reputation-based schemes are increasingly becoming popular for enforcing security in wireless networks. A number of open problems in security and privacy issues for WMNs are subsequently discussed before the chapter is finally concluded.Comment: 62 pages, 12 figures, 6 tables. This chapter is an extension of the author's previous submission in arXiv submission: arXiv:1102.1226. There are some text overlaps with the previous submissio