Non-contact rack and pinion powered by the lateral Casimir force

The lateral Casimir force is employed to propose a design for a potentially wear-proof rack and pinion with no contact, which can be miniaturized to nano-scale. The robustness of the design is studied by exploring the relation between the pinion velocity and the rack velocity in the different domains of the parameter space. The effects of friction and added external load are also examined. It is shown that the device can hold up extremely high velocities, unlike what the general perception of the Casimir force as a weak interaction might suggest.Comment: 4 pages, submitted for publication on 17 Jan 0

Effect of the Heterogeneity of Metamaterials on Casimir-Lifshitz Interaction

The Casimir-Lifshitz interaction between metamaterials is studied using a model that takes into account the structural heterogeneity of the dielectric and magnetic properties of the bodies. A recently developed perturbation theory for the Casimir-Lifshitz interaction between arbitrary material bodies is generalized to include non-uniform magnetic permeability profiles, and used to study the interaction between the magneto-dielectric heterostructures within the leading order. The metamaterials are modeled as two dimensional arrays of domains with varying permittivity and permeability. In the case of two semi-infinite bodies with flat boundaries, the patterned structure of the material properties is found to cause the normal Casimir-Lifshitz force to develop an oscillatory behavior when the distance between the two bodies is comparable to the wavelength of the patterned features in the metamaterials. The non-uniformity also leads to the emergence of lateral Casimir-Lifshitz forces, which tend to strengthen as the gap size becomes smaller. Our results suggest that the recent studies on Casimir-Lifshitz forces between metamaterials, which have been performed with the aim of examining the possibility of observing the repulsive force, should be revisited to include the effect of the patterned structure at the wavelength of several hundred nanometers that coincides with the relevant gap size in the experiments.Comment: 9 pages, 13 figures. Rewriting equations (10) and (12) and increasing the size of the lettering/numeral in figure

ANTI-FERTILITY EFFECTS OF DIFFERENT FRACTIONS OF ANETHUM GRAVEOLENS L. EXTRACTS ON FEMALE RATS

Our previous studies showed the effects of aqueous and ethanol extracts of Anethum graveolens L. (dill) on female infertility. In the present study we investigated whether different fractions of this herb extract can cause infertility in rats. Female rats were divided into the control groups, the groups receiving either a low (0.5 g/kg)) or a high dose (5g/kg) of water, N-butanol, chloroform and ether fractions of the aqueous plant extract, and the groups receiving either a low (0.045 g/kg) or a high dose (0.45 g/kg) of the same fractions of ethanol extract. The mentioned doses were gavaged in 1mL for 10 days. Vaginal smears were prepared daily. Estradiol and progesterone levels were measured. The left oviduct and ovary were removed, their tissue subsequently being prepared in form of histology slides and stained using haematoxylin-eosin and Masson’s trichrome. Female rats assigned to each group were mated with males; after that, crown-rump lengths and weights of newborn rats were measured. Results showed that each fraction produced some changes such as hormonal level reduction (chloroform fraction), diestrus phase prolongation and infertility (water fraction), and increase in pregnancy duration (chloroform and ether fractions). We concluded that each fraction comprises only some of the mentioned components and therefore recommended the usage of crude extract, especially the aqueous one, in case infertility aims to be induced

Behavioural and molecular study of the effects of rosuvastatin on acquisition and retention of spatial memory impaired by H-89 in rats

There is controversy on the effect of statins on cognitive functions such as spatial memory. In the present study, effect of ten- day oral gavage of rosuvastatin (Ros, 20 mg/kg) on spatial learning and spatial memory retention impaired by H-89, was investigated in male rats. This study was comprised of two sets of experiments each including the following 3 groups (n = 8): Control group treated with DMSO; H-89 group received bilateral intra-hippocampal H-89 (10 μM/side, in DMSO) and Ros- H-89 group orally treated with Ros (20 mg/kg) and H-89 (similar to the H-89 group). For spatial learning (acquisition phase) assessment, from day 7 of Ros gavage, rats were trained in the Morris water maze (MWM) for four days (one block of 4 stages each day) and received daily H-89, 30 min after Ros gavage. On day 11, the probe test was performed. Also, to assess spatial memory retention, from day 7 to 10 of Ros gavage, rats were trained in MWM but received H-89 on day 10 only. On day 12, the probe test was performed. Besides, CREB and p-CREB protein expression was assessed in hippocampal samples and oxidative stress status was assessed in serum samples. We observed that H-89 led to a clear impairment of the spatial learning and spatial memory recall, increased levels of lipid peroxidation and downregulated CREB and p-CREB proteins, compared to the control group. However, Ros prevented H-89-induced deleterious consequences which might be probably in part due to its ameliorative effects on lipid peroxidation index and CREB and p-CREB expression

Motion-Induced Radiation from a Dynamically Deforming Mirror

A path integral formulation is developed to study the spectrum of radiation from a perfectly reflecting (conducting) surface. It allows us to study arbitrary deformations in space and time. The spectrum is calculated to second order in the height function. For a harmonic traveling wave on the surface, we find many different regimes in which the radiation is restricted to certain directions. It is shown that high frequency photons are emitted in a beam with relatively low angular dispersion whose direction can be controlled by the mechanical deformations of the plate.Comment: 4 pages, 2 eps figues included, final version as appeared in PR

Factors Associated with The Incidence of Coronary Heart Disease in The Mashad: A Cohort Study

Coronary heart disease (CHD) is the leading cause of morbidity and mortality globally, and specifically in Iran. Accurate assessments of Coronary heart disease (CHD) incidence is very necessary for public health. In current study we aimed to investigate the incidence of CHD and importance of several classical, modifiable and un-modifiable risk factors for CHD among an urban population in eastern Iran after 6 years of follow-up. Methods The population of MASHAD cohort study were followed up for 6 years, every 3 years in two step by phone and who reported symptoms of CVD were asked to attend for a cardiac examination, to estimate the incidence of CHD with 95% confidence interval (95% CI) as well multiple logistic regression analysis was performed to assess the association of several baseline characteristics with incidence of CHD event. Evaluation of goodness-of-fit was done using ROC analysis. CHD cases divided into four different classes which include: stable angina, unstable angina pectoris, myocardial infarction and sudden cardiac death. Results In the six years\u27 follow-up of Mashhad study, the incidence rate of all CHD event in men and women in 100,000 people-years with 95% confidence intervals were 1920 (810-3030) and 1160 (730-1590), respectively. The areas under ROC curve (AUC), based on multivariate predictors of CHD outcome, was 0.7825. Conclusion Our findings indicated that the incidence rate of coronary heart diseases in MASHAD cohort study increases with age as well as our final model designed, was able to predict approximately 78% of CHD events in Iranian population

The `Friction' of Vacuum, and other Fluctuation-Induced Forces

The static Casimir effect describes an attractive force between two conducting plates, due to quantum fluctuations of the electromagnetic (EM) field in the intervening space. {\it Thermal fluctuations} of correlated fluids (such as critical mixtures, super-fluids, liquid crystals, or electrolytes) are also modified by the boundaries, resulting in finite-size corrections at criticality, and additional forces that effect wetting and layering phenomena. Modified fluctuations of the EM field can also account for the `van der Waals' interaction between conducting spheres, and have analogs in the fluctuation--induced interactions between inclusions on a membrane. We employ a path integral formalism to study these phenomena for boundaries of arbitrary shape. This allows us to examine the many unexpected phenomena of the dynamic Casimir effect due to moving boundaries. With the inclusion of quantum fluctuations, the EM vacuum behaves essentially as a complex fluid, and modifies the motion of objects through it. In particular, from the mechanical response function of the EM vacuum, we extract a plethora of interesting results, the most notable being: (i) The effective mass of a plate depends on its shape, and becomes anisotropic. (ii) There is dissipation and damping of the motion, again dependent upon shape and direction of motion, due to emission of photons. (iii) There is a continuous spectrum of resonant cavity modes that can be excited by the motion of the (neutral) boundaries.Comment: RevTex, 2 ps figures included. The presentation is completely revised, and new sections are adde

A frustrated non-contact rack-pinion-rack device

A design is proposed for a mechanical device made of a nanoscale pinion sandwiched without contact between two racks that exert opposing forces rooted in the quantum fluctuations of the electromagnetic field via the lateral Casimir force. The built-in frustration in the design of the system helps it to react dramatically to minute changes in the geometrical features, which suggests that it could act as a good sensor. The noncontact nature of this device could help solve the infamous wear problem in nanoscale mechanical devices. © 2009 IOP Publishing Ltd

The Impact of Customer Relationship Factors on Brand Equity : In Suppliers Companies of Iranian Petrochemical Industry

The main purpose of the thesis is to determine the degree of relationship between customer relationships and brand equity in the customer-based brand equity (CBBE) perspective. The lack of comprehensive and approved definition of brand equity (BE) has in turn produced various methodologies to measure the construct. Even though there is no generally accepted definition of BE, there is some consensus in that BE indicates the added value endowed by the brand for product. Brand equity is based on the product position of the brand in the mind of customers. A consumer who believes that a brand delivers superior performance is excited to use the product, and is likely to be willing to pay a premium for the brand, and to go to extra trouble to locate and buy it, to recommend it to others, to forgive a mistake or product flaw, or to otherwise engage in behaviors that benefits the firm that markets the brand. Thus, one source of economic value from a positive brand image results from consumers’ behaviors toward existing items with that brand name. The study presents several objectives such as customer relationships and Brand equity that provide new insight in Brand equity (BE) areas. Our study develops a theory-based framework and empirically exhibits that exploration and exploitation are major constructs that can positively effect on overall brand equity for the improvement of long-term relationships in the petrochemical suppliers companies. We have selected 400 companies of Petrochemical industry suppliers as population sample size. Descriptive analysis, and structural equation model (SEM) has been developed on collected data. The result shows that Factors of customer relationships such as Trust, customer satisfaction and relationship commitment has a significant effect on brand equity in suppliers companies of Iranian Petrochemical industry.Validerat; 20160607 (marikav