Hybrid metallic nanoparticles for excitation of surface plasmon resonance

A Ag nanostructure was put forward in this paper. There are two types of Ag nanoparticles, spherical and pyramidal particles. Both of them have the same period, but different height and shapes. The hybrid nanoparticles can produce the localized surface plasmon resonance (LSPR), which couples each other and leads to an extra peak transmission. Our UV-visible-IR spectrophotometer measurement results show that some extra small and sharp peaks appear besides the normal LSPR wave peaks in the transmittance spectrum. The hybrid Ag nanoparticles being used as nanosensors will be more sensitive and selective than the conventional LSPR-based nanosensors. © 2007 American Institute of Physics

An Improved UFLS Scheme based on Estimated Minimum Frequency and Power Deficit

In the event of a power system disturbance, it is important that the decision to implement under frequency load shedding is based on both the minimum frequency and the magnitude of the disturbance. In this paper, we propose the use of higher order polynomial curve fitting to estimate the minimum frequency. If the prediction shows that the minimum frequency threshold will be violated, the magnitude of the total disturbance is estimated using the swing equation. In addition, the minimum amount of load that must be shed to restore the frequency just above the minimum value can also be directly calculated. Simulations are carried out for the considered Taiwan power system and the results prove the efficiency of the proposed technique

Application of Brownian motion theory to the analysis of membrane channel ionic trajectories calculated by molecular dynamics

This paper shows how Brownian motion theory can be used to analyze features of individual ion trajectories in channels as calculated by molecular dynamics, and that its use permits more precise determinations of diffusion coefficients than would otherwise be possible. We also show how a consideration of trajectories of single particles can distinguish between effects due to the magnitude of the diffusion coefficient and effects due to barriers and wells in the potential profile, effects which can not be distinguished by consideration of average fluxes

Advanced breast cancer and its prevention by screening.

In discussions on breast cancer screening, much attention has been focussed on the possible morbidity generated by screening. Favourable effects like the prevention of advanced disease seem underestimated, probably because quantification is that difficult. To analyse the amount of care and treatment given to women with advanced breast cancer, we report on patients followed from first recurrence until death using patient files and national sources. A random sample of 60 female cases from computerised registries of two cancer centres and a sample of 20 cases from a non-computerised hospital registry was taken. A total of 68 patient files were sufficiently documented. A woman with advanced breast cancer is estimated to have a 39% loss in utility compared to a healthy woman (range 27-45%). Hormonal treatment is the main modality during 14 and chemotherapy during 4 months. Total medical cost from diagnosis of advanced disease until death amounts to 17,100 US dollars, or 21,000 when including extramural cost. The effect of breast cancer screening by preventing the occurrence of advanced disease is quantified. The resulting gain in quality of life contributes 70% of the total gain in quality of life. In the long run, almost half of the annual cost of screening will be offset by savings in the cost for advanced disease. Only the changes in palliative surgery and/or radiotherapy will be small in contrast to primary treatment changes. Besides the mortality reduction, screening is justified by the improvements in quality of life and cost savings for women prevented from reaching advanced disease

An Isolated, Antegrade, Perfused, Peroneal Nerve Anterior Tibialis Muscle Model in the Rat A Novel Model Developed to Study the Factors Governing the Time Course of Action of Neuromuscular Blocking Agents

Background: A model of an antegrade, perfused, isolated rat peroneal nerve anterior tibial muscle was developed to study potentially important factors governing the time course of action of (nondepolarizing) neuromuscular blocking agents such as concentration, blood flow, and temperature. The model allows observation of the effects of selective changes in these factors. Methods: The authors isolated the anterior tibial muscle and cannulated the anterior tibial artery and vein, providing a way for single-pass perfusion with blood from a donor rat. A force transducer was connected to the tibialis anterior muscle and a stimulator was connected to the tibial nerve. The influence of intrinsic potency (EC 90 ) and muscle blood flow rate on the time course of pancuronium and rocuronium was investigated. Results: The model remained stable for at least 4 h with respect to twitch height, muscle structure and function, and blood chemistry. Doubling the muscle-blood flow resulted in a significantly faster onset and offset for both pancuronium and rocuronium. Trebling the intrinsic potency (EC 90 ) was not associated with significant changes in the time course of action of the relaxants. Conclusion: The authors developed and validated a model that allows us to study biophase kinetics of neuromuscular blocking agents in the anterior tibial muscle of the rat. In this model, muscle-blood flow rather than EC 90 appears to predominantly determine the onset and offset time of nondepolarizing muscle relaxants

Threat of a lion population extinction in Waza National Park, North Cameroon.

Conservation Biology - ol

Torsades de pointes during laparoscopic adrenalectomy of a pheochromocytoma: a case report

<p>Abstract</p> <p>Introduction</p> <p>Torsades de pointes is a rare but potentially lethal arrhythmia. The amount of literature available on Torsades de pointes occurring in patients with pheochromocytoma is limited, and we found no literature describing this dysrhythmia in a patient with pheochromocytoma under anesthesia.</p> <p>Case presentation</p> <p>We describe the case of a 42-year-old Caucasian woman without QT prolongation preoperatively with recurrent Torsades de pointes during laparoscopic removal of a pheochromocytoma. Torsades de pointes mainly occurs in the setting of a prolonged QT interval. This patient neither had a prolonged QT preoperatively nor was her family history suspect for a congenital long QT syndrome. Most likely, our patient had an acquired long QT syndrome, elicited by the combination of flecainide, hypomagnesemia and adrenergic stimulation during manipulation of the tumor.</p> <p>Conclusion</p> <p>We show that in the case of a surgical pheochromocytoma removal, perioperative conditions can elicit an acquired or previously unknown congenital long QT syndrome. Therefore, preoperative α- and β-blockade is advised, QT-prolonging drugs should be avoided and potassium and magnesium plasma levels should be kept at normal to high levels.</p