Selectivity of LG50643 for postjunctional muscarinic-receptor subtype in the guinea-pig trachea

The effects of (+/-)-LG50643, a new N-quaternary tropinic ester of phenylcyclohexene carboxylic acid, endowed with a potent antimuscarinic activity, have been investigated on muscarinic receptor-mediated responses of the guinea-pig trachea to electrical field stimulation. An isolated preparation which allows the simultaneous measurement of tritiated acetylcholine release (prejunctional effect) and smooth muscle contraction (postjunctional effect) was used. The guinea-pig epithelium-deprived trachea was stimulated with 500 pulses (20 Hz, 1 ms, 9 V for 5 s, 30 s apart) in the presence of indomethacin (1 microM). Three successive pre- and postjunctional responses were observed. The potencies (-logEC50) of (+/-)-LG50643 for pre- and postjunctional muscarinic receptors were determined and compared with those of selective muscarinic antagonists. In addition, the affinity values of (+/-)-LG50643 for muscarinic-receptor subtypes were determined in radioligand binding experiments in cerebral cortex, heart and salivary glands of rat as target tissues for M1, M2 and M3 receptors, respectively. The results obtained in both functional and binding assays indicate (+/-)-LG50643 is a potent and selective antagonist for the M3-receptor subtype.     

Analytic physics-based expressions for the empirical parameters ofthe Statz-Pucel MESFET model

The authors present a novel approach to the evaluation of the DC parameters of a semiempirical MESFET model: starting from the analytical expression of the drain current derived from a previously proposed physics-based model, they provide a method to calculate the empirical DC parameters of the so-called Raytheon model. The comparison between computed and measured DC characteristics is quite satisfactory on GaAs microwave FETs of 1 μm or more gate length. By adding to the results obtained in this work an adequate model of the stray capacitances, the circuit performance can be optimized using the technological characteristics of active devices     

Comparative review of the adverse effects of sedatives used in children undergoing outpatient procedures

Children often fear medical procedures and interventions. Sedative agents enhance the care of these children who undergo outpatient procedures by decreasing anxiety, increasing cooperativity, and providing amnesia. Although higher dosages and intravenous administration of sedatives often produce improved sedation, adverse effects and complications are more frequent. The goals of therapeutic efficacy and safety must be balanced in all patients. The presence or anticipation of anxiety and pain helps in deciding whether to use a sedative alone, or a regimen also providing analgesia. The patient's clinical cardiorespiratory or neurological status, other relative contraindications, the duration of the intended procedure, and the presence or absence of an intravenous line will help in choosing specific drugs. Drug complications are a common cause of adverse events in patients. The combination of a sedative and analgesic, especially a benzodiazepine and an opioid given intravenously, is associated with a higher risk of serious complications. The practitioner responsible for the administration of a sedative to a child must be competent in its use and have the ability to detect and manage complications. Patients who are deeply sedated should be continuously monitored and observed by an individual dedicated to this task. Vital signs and oxygen saturation should be documented at frequent intervals and the patient should be appropriately monitored until discharge criteria have been met. The risk of serious complications with these agents may be reduced with vigorous monitoring and a judicious choice of dosage.     

The interpretation of the English landscape garden between 1815 and 1840 through Xavier Kurten’s work in Piedmont (north-west Italy)

Xavier Kurten (?–1840) was a Prussian landscape gardener who worked for the Savoy family in the Piedmont region of Italy in the first half of the nineteenth century. He designed or redesigned all royal parks, creating a specific style based on the English naturalistic garden approach. This research was performed with the aim of investigating the development of the English landscape garden in Italy. Historical documents relating to Kurten’s biography and his work in Piedmont, including plans, were collected and analysed. We analyse and discuss the features that characterised his work: the relationship between the landscape—garden—house, the path system, the use of water, the vegetation, and the garden as a productive landscape. Kurten’s style is compared with the projects of William Kent and Lancelot ‘Capability’ Brown.     

Effect of ultraviolet processing on selected properties of egg white

The effect of ultraviolet processing (10.6 and 63.7 kJ m(-2)) on selected properties of egg white (absorbance, particle size, protein fractions, free sulfhydryl content, immunoreactivity, viscosity, gelling and foaming properties) was investigated. Ultraviolet exposure induced the development of browning, the formation of large protein aggregates by disulfide exchange, and protein backbone cleavage. However, egg white proteins were differently sensitive to UV radiation. No changes in immunoreactivity, gelling temperature and gel firmness were observed. Independently on the UV dose, light treated egg white produced foams with higher stability. This effect was attributed to protein aggregates jamming in the fluid interstices between bubbles and/or to the higher viscosity of the aqueous phase. The latter was also associated to higher foam volume.     

Sensitivity analysis of TWT's small signal gain based on the effectof rod shape and dimensions

An extensive study aiming at analyzing the effect of rod shapes and dimensions on the gain of helix traveling wave tubes (TWTs) is performed. The evaluation of tube small-signal gain is obtained by making use of a rigorous field analysis which takes into account the helix tape model and the dielectric inhomogeneous loading conditions. Computing time to perform the analysis is extremely low compared with the time required in the case of a full wave, three-dimensional (3-D) electromagnetic simulator. The accuracy of the simulation approach has been extensively verified in a previous paper. A novel expression for the attenuation constant has been introduced in the model to improve the quality of results. The proposed study allows a better understanding of tube behavior before fabrication highlighting the contribution of the shape, the mechanical tolerances and the ϵ_r variation of the rods to the small-signal gain