Study on Composition Distribution and Ferromagnetism of Monodisperse FePt Nanoparticles

Monodisperse FePt nanoparticles with size of 4.5 and 6.0 nm were prepared by simultaneous reduction of platinum acetylacetonate and thermal decomposition of iron pentacarbonyl in benzylether. The crystallography structure, size, and composition of the FePt nanoparticles were examined by X-ray diffraction and transmission electron microscopy. Energy dispersive X-ray spectrometry measurements of individual particles indicate a broad compositional distribution in both the 4.5 and 6 nm FePt nanoparticles. The effects of compositional distribution on the phase-transition and magnetic properties of the FePt nanoparticles were investigated.     

Influence of calcium on the true acrosome reaction and capacity of bull spermatozoa to penetrate oocytes in vitro

A series of experiments were conducted to determine the role of Ca in several physiological functions of bovine spermatozoa. For spermatozoa incubated in the absence of Ca for up to 24 h, motility was not different from those incubated with Ca. For spermatozoa incubated in the continuous presence of Ca, true acrosome reaction values were 0% at 0 h, 1.5% at 6 h, and 6.0% at 12 h. Spermatozoa incubated in vitro for up to 12 h in the absence of Ca did not undergo a true acrosome reaction; however, when Ca was added during incubation, a synchronous true acrosome reaction was induced within 10 min (0% at 0 h, 8.5% at 6 h, and 8.5% at 12 h). When spermatozoa were preincubated in the presence or absence of Ca for 6 h, then added to zona-intact dead bovine oocytes and incubation continued with and without Ca for 18 h, the number of spermatozoa binding to and penetrating each oocyte was greater when Ca was present. Also, the percentage of oocytes being penetrated was greater when Ca was present. These results indicate that: 1) Ca is not necessary for maintenance of spermatozoan motility; 2) Ca is required for the induction of a true acrosome reaction among a population of spermatozoa; 3) Ca is able to induce the synchronous true acrosome reaction in a low percentage of spermatozoa; and 4) Ca is important in spermatozoan binding and initiation of penetration of oocytes.     

Price Caps for Standard Offer Service: A Hidden Stranded Cost

The use of call option techniques demonstrates that the flexibility offered by standard offer service can be a non-trivial fraction of total stranded costs. The right price cap structure can ameliorate this cost.     

Design patterns for behavior-based robotics

The use of patterns allows proven design expertise to be captured, communicated and reused in areas such as architecture and object-oriented programming. The artificial intelligence discipline of behavior-based robotics is an area in which such design expertise has undoubtedly accumulated, although it has not been captured and formalized. Consequently, the creation of these robotic systems remains a relatively unstructured process requiring a large amount of trial-and-error development. There is therefore a strong case for representing the previous design expertise which has been developed in this field. This paper describes how this may be achieved through the use of design patterns     

Development and characterization of genetic mapping resources for the turkey (Meleagris gallopavo)

The development and partial characterization of turkey genomic libraries enriched for TG, GAT, and CCT simple sequence repeats (SSR) are described. The primary library, established using conventional methods, was enriched for each of the three SSR by single-primer polymerase chain reaction (PCR). The three enriched libraries were screened by standard hybridization and washing protocols under moderate to high stringency conditions. The utility of a fraction of the markers was evaluated based on the polymorphism of PCR-amplified products in a backcross reference DNA panel. The panel consisted of genomic DNA samples from three backcrossed families developed from a cross of a wild male turkey to three inbred Orlopp line C females. A total of 181 sequences from positive clones have been characterized and deposited in GenBank. About 60% of the 60 primer pairs designed from SSR-containing sequences detected polymorphism in the reference DNA panel. The turkey genomic DNA reference panel, the enriched libraries, and the markers described here provide an opportunity to begin to characterize the turkey genome and to develop a useful public genetic map for this economically important species.     

The linear R&D project selection problem: an alternative to netpresent value

An alternative to the net present value (NPV) formulation of the objective in problems involving choice between cash flows over time is presented. This approach is illustrated in an R&D project selection problem. It is shown that the NPV formulation is a special case of optimizing a multiattribute value function. This special case requires restrictive assumptions about the decision-maker's preferences over time. The authors suggest instead that multiobjective linear programming methods be used to produce a set of nondominated solutions. This methodology is analytically tractable and requires no assumptions about the decision-maker's time preferences     

Norepinephrine release in the human forearm: effects of epinephrine

It has been postulated that delayed facilitation of norepinephrine release by epinephrine is causally related to the development of hypertension. It has been proposed that a brief increase in epinephrine concentrations results in the uptake of epinephrine into the sympathetic nerve terminal. Subsequent rerelease of epinephrine stimulates presynaptic beta-adrenergic receptors, resulting in a prolonged increase in plasma norepinephrine (NE) concentrations, with amplified sympathetic responses and vasoconstriction. To determine whether such epinephrine-induced, delayed facilitation of NE release occurs in a vascular bed draining resistance vessels and, if it occurs, whether that facilitation differs in hypertension, we used a radioisotope dilution method to measure unstimulated and isoproterenol-stimulated forearm NE spillover before, during, and after a 50 ng/min infusion of epinephrine for 30 minutes directly into the brachial artery. No delayed facilitatory effects of epinephrine on forearm NE spillover were observed in either 6 normotensive (NT) or 8 borderline hypertensive (BHT) subjects (NT unstimulated forearm NE spillover preepinephrine 1.79+/-0.41 ng/min versus postepinephrine 2.36+/-0.65 ng/min, P=.38; BHT preepinephrine 2.24+/-0.70 ng/min versus postepinephrine 1.93+/-0.46 ng/min, P=.51; NT isoproterenol-stimulated forearm NE spillover preepinephrine 4.61+/-1.01 ng/min versus postepinephrine 4.4+/-0.98 ng/min, P=.9; BHT preepinephrine 4.04+/-1.36 ng/min versus postepinephrine 4.69+/-1.49 ng/min P=.5). We conclude that the short-term local infusion of epinephrine does not have a delayed facilitatory effect on forearm NE spillover in NT or BHT subjects. Therefore, the prolonged increase in NE concentrations after epinephrine infusion previously shown systemically, and not seen locally in the forearm, suggests that the delayed facilitatory response to epinephrine may occur in other organs.