On a Kelvin-Voigt Viscoelastic Wave Equation with Strong Delay

An initial-boundary value problem for a viscoelastic wave equation subject to a strong time-localized delay in a Kelvin & Voigt-type material law is considered. Transforming the equation to an abstract Cauchy problem on the extended phase space, a global well-posedness theory is established using the operator semigroup theory both in Sobolev-valued $C^{0}$- and BV-spaces. Under appropriate assumptions on the coefficients, a global exponential decay rate is obtained and the stability region in the parameter space is further explored using the Lyapunov's indirect method. The singular limit $\tau \to 0$ is further studied with the aid of the energy method. Finally, a numerical example from a real-world application in biomechanics is presented.Comment: 34 pages, 4 figures, 1 set of Matlab code

A new look at the modified Coulomb potential in a strong magnetic field

The static Coulomb potential of Quantum Electrodynamics (QED) is calculated in the presence of a strong magnetic field in the lowest Landau level (LLL) approximation using two different methods. First, the vacuum expectation value of the corresponding Wilson loop is calculated perturbatively in two different regimes of dynamical mass $m_{dyn.}$, {\it i.e.}, $|{\mathbf{q}}_{\|}^{2}|\ll m_{dyn.}^{2}\ll |eB|$ and $m_{dyn.}^{2}\ll |\mathbf{q}_{\|}^{2}|\ll|eB|$, where $\mathbf{q}_{\|}$ is the longitudinal components of the momentum relative to the external magnetic field $B$. The result is then compared with the static potential arising from Born approximation. Both results coincide. Although the arising potentials show different behavior in the aforementioned regimes, a novel dependence on the angle $\theta$ between the particle-antiparticle's axis and the direction of the magnetic field is observed. In the regime $|{\mathbf{q}}_{\|}^{2}|\ll m_{dyn.}^{2}\ll |eB|$, for strong enough magnetic field and depending on the angle $\theta$, a qualitative change occurs in the Coulomb-like potential; Whereas for $\theta=0,\pi$ the potential is repulsive, it exhibits a minimum for angles $\theta\in]0,\pi[$.Comment: V1: 26 pages, 8 figures, latex format, V2: Accepted for publication in PRD (2007

Replacement of dietary fish meal with plant sources in rainbow trout (Oncorhynchus mykiss); effect on growth performance, immune responses, blood indices and disease resistance

The aim of this study was to examine the effects of replacing fish meal with plant sources on growth performance, immune responses, hematological parameters and disease resistance in rainbow trout. In this study, mean of initial body weight of fish was 15±2 g and the experiment was carried out for a period of 60 days. Four experimental diets were formulated to replace 0, 40, 70 and 100% fish meal with plant protein sources (wheat gluten, corn gluten and soybean meal). According to results, higher plant protein inclusions (70 and 100%) resulted in undesirable effects on growth, nutritional indices, serum total immunoglobulin and alternative complement activity (P 0.05). Furthermore, replacement of fish meal with plant sources in all treatments had no significant effects on blood parameters (hematocrit, hemoglobin, white blood cells, hetrophil and lymphocytes count). Finally, no significant differences were observed in fish mortality after 15 days of challenges with Yersinia ruckeri among treatments (P > 0.05)

Voltage control in distributed generation systems based on complex network approach

In this paper, a new approach for modeling of voltage control problem in distributed generation systems based on the complex network theory is proposed. Distributed generationsystems (DGS) including renewable energy sources are highly complex nonlinear dynamical systems by nature. There are many theoretical and practical challenges to apply the existing control technologies to them. The novel approach, introduced in this paper, embeds the complex network theory into the voltage control problem of DGS; i.e. the voltage control of DGS is introduced as a synchronization problem in complex networks. Complex network methodology shows a promising simplification inthe analysis as well as timely response in large-scale systems. Thanks to the well-developed graph theory as well as advancements in control of multi-agent systems,the model presented in this paper, candealwith real-time hierarchical multi-objective requirements of control problems in DGS. Finally, the pinning control approach is applied to the model in order to solve the voltage synchronization problem of the microgrid

Study of measuring Tilapia (Oreochromis niloticus) freshness using quality index method (QIM)

Fish freshness by using QIM and according to scoring to all of parts variable (positive and negative) was by sensory method and finally become the parameters of quantitative and qualitative with statistical analysis is based, tables used in volatility score of 0 to 23, with a score of 0 to 3 respectively, for their excellent quality, 3 to 7good, from 7 to 10 and from 10 to above average evaluation is unacceptable. In this study to measure the freshness of fish species Nile Tilapia (Oreochromis niloticus), black and red in 4 treatments, whole fish and empty stomach is considered and the objective of this study was to calculate the survival rate of fish in ice cover practically immediately after harvest to measure qualitative factors (sensory evaluation, chemical and microbiological).For this study 50 pieces of red and 50 pieces black Tilapia after weighed, washed and then selection 25 pieces for each treatment in unlit, ratio of 3 to 1 (ice - fish) was covered .The mean (± SD) change in temperature the fish flesh during study were between 0.2 ±0.07 a to 0.3 ±0.1a degrees Celsius, that need to raise the quality temperature is maintained at 0 degrees Celsius in unlit center. Fish covered with ice keep at ambient temperature, and after measuring the change free nitrogen, pH and microbial tests, the results showed maximum shelf life of whole fish in ice cover 9 and for empty stomach fish was7 days .And also statistical analysis (Duncan test) of data between treatments (Whole and empty fish covered in ice ) was significant (P<0.05)

CXCL12-CXCR4 axis: its role and the drug inhibitors on each type of cancers

Objective: Chemokine 12, C-X-C Motif Chemokine Ligand 12 (CXCL12), and its receptor C-X-C Motif Chemokine Ligand 4 (CXCR4), both play essential and critical roles in the development of different types of cancers. Almost, in all of the cancers, overexpression of these two chemokines is a key to diagnose of cancers and lead them to progress, an increment in proliferation, the invasive feature of different cell lines, metastasis, and a noticeable decrement in apoptosis. Although the impact of this axis on cancer development is known and investigated, there was no review article about this molecular pathway and the drug effects on this cascade is not written. In this regard, we probed the researches about this intracellular process and the drugs that are useful for suppressing it on one-by-one cancer. Materials and Methods: We reviewed this study with scientific keywords in ScienceDirect, Google Scholar, and PubMed. Our research process was to review every study that has looked at this process in every cancer, as well as the drugs selected to treat cancer from 14 years ago onwards. Results: Our researches showed that there are some inhibitors that are introduced in order to block the pathway in many cancers. In addition, the data related to the effect of this pathway on some types of cancers are not enough. Conclusions: Summing up, the present study clears a route to suppress the invasion of cancers and bold the tips that have not been worked on yet

Anti-invasion and anti-metastasis effects of Dandelion (Taraxacum officinale) hydroalcoholic extract on glioblastoma multiforme cell line model

OBJECTIVE: Glioblastoma multiforme is one of the malignant brain tumors and despite recent advancements in cancer treatment remains largely incurable. Cancer invasion has a cascade of interrelated and sequential steps, including cell adhesion, extracellular matrix degradation, and cell movement. Hence, inhibition of the invasion-associated steps could be a potential strategy for prolonging the life of patients. This study aimed to evaluate the anti-invasion and anti-metastasis effects of Dandelion (Taraxacum officinale) hydro-alcoholic extract on glioblastoma multiforme cell line (U87MG). MATERIALS AND METHODS: The hydro-alcoholic extract was prepared, and the cell line was treated with 1000, 500, 250, 125, and 62.5 µg / ml of extract for 24, 48, and 72 hr. Cell viability was evaluated. The effect of extract (IC50 concentration) on cancer cell invasion potential was tested. The expression levels of MMP-2, MMP-9, TIMP-1, TIMP-2, uPA, uPAR, p38MAPK, ERK1/2, and SAPK/JNK were analyzed. Comparisons between groups were performed by Tukey’s test one-way analysis of variance and differences were considered significant when p < 0.05. RESULTS: After treatment with extract, the cells viability was decrease in a concentration- and time-dependent. IC50 concentration of dandelion extract significantly decreased the cell migration by 32% (p<0.05), cell invasion potential by 77% (p<0.05) and cell adhesion by 51% (p<0.05). Also, the expression levels of proteolytic enzymes associated with matrix and base membrane degradation (MMP-2, MMP-9, and uPA) were decreased and the levels of their endogenous inhibitors (TIMP1 and TIMP2) were increased. Moreover, the p38MAPK and SAPK/JNK signaling pathway, which stimulates proteolytic enzymes and matrix degradation, was inhibited by extract treatment. CONCLUSIONS: Dandelion extract reduced the viability and invasion potential of the glioblastoma cells by regulating proteolytic enzymes and matrix dynamics through the p38MAPK and SAPK/JNK pathway

Pogostone effect on dacarbazine-induced autophagy and apoptosis in human melanoma cells

Objective: Chemotherapy is effective for treating malignant melanoma, but drug resistance and occurrence of side effects limited this strategy. The balance between autophagy and apoptosis has an essential role in the chemotherapy of cancers. The present investigation aims to examine the efficacy of pogostone (isolated from Pogostemon cablin L.) on the ratio of apoptosis and autophagy caused by dacarbazine in melanoma cells. Materials and Methods: Human melanoma cells were exposed to different concentrations of dacarbazine and pogostone, and the IC50 values were calculated. The cells were treated with two concentrations higher and lower than IC50 simultaneously, and the dose reduction index and combination index (CI) parameters were calculated. The occurrence of apoptosis and autophagy was evaluated. The expression level of genes related to apoptosis and autophagy pathways was tested. Results: Pogostone and dacarbazine declined the number of the cells in a dose and time-dependent manner and showed a synergistic effect. There was a significant decrease in autophagy in the co-treatment besides the dacarbazine alone (p < 0.05). There was a considerable increment in apoptosis in cultures treated with pogostone and dacarbazine (p < 0.05). Also, Real-time PCR data confirmed the obtained results. Conclusions: Pogostone reduced melanoma cell resistance to dacarbazine via autophagy blockage