Effects of late-season sheep grazing following early-season steer grazing on population dynamics of sericea lespedeza in the Kansas Flint Hills.

Mature ewes were used in a 4-yr study to evaluate effects of intensive late-season sheep grazing on vigor of sericea lespedeza in native tallgrass prairie. Pastures ( = 8; 31 ± 3.6 ha) infested with sericea lespedeza (initial basal frequency = 1.

Effects of prescribed fire timing on grazing performance of yearling beef cattle, forage biomass accumulation, and plant community characteristics on native tallgrass prairie in the Kansas Flint Hills.

Recent research demonstrated that mid- or late-summer prescribed fires can be employed to manage sericea lespedeza () infestations in the Kansas Flint Hills. The effects of prescribed fire applied during the growing season (i.e.

Effects of prescribed fire timing on vigor of the invasive forb sericea lespedeza (), total forage biomass accumulation, plant-community composition, and native fauna on tallgrass prairie in the Kansas Flint Hills.

The predominant grazing-management practice of the Kansas Flint Hills involves annual prescribed burning in March or April with postfire grazing by yearling beef cattle at a high stocking density from April to August. There has been a dramatic increase in sericea lespedeza ( [Dumont] G. Don) coincident with this temporally focused use of prescribed fire in the Flint Hills region.

GDNF revisited: A novel mammalian cell-derived variant form of GDNF increases dopamine turnover and improves brain biodistribution.

Parkinson's disease (PD) is a disorder affecting dopamine neurons for which there is no cure. Glial cell line-derived neurotrophic factor (GDNF) and the closely related protein neurturin are two trophic factors with demonstrated neuroprotective and neurorestorative properties on dopamine neurons in multiple animal species. However, GDNF and neurturin Phase-2 clinical trials have failed to demonstrate a significant level of improvement over placebo controls.

Continuous intranigral infusion is not associated with observable behavioral deficits or marked pathology: a preclinical safety study.

OBJECTIVE A better understanding of the effects of chronically delivering compounds to the substantia nigra and nearby areas is important for the development of new therapeutic approaches to treat alpha-synucleinopathies, like Parkinson's disease. Whether chronic intranigral delivery of an infusate could be achieved without causing motor dysfunction or marked pathology remains unclear. The authors evaluated the tolerability of continuously delivering an infusate directly into the rhesus monkey substantia nigra via a programmable pump coupled to a novel intraparenchymal needle-tip catheter surgically implanted using MRI-guided techniques.

Right ventricular outflow tract reconstructive model in adult sheep.

Patients born with congenital right ventricular outflow tract lesions are faced with invasive procedures to establish hemodynamic and physiological stability. Commonly, multiple subsequent surgical procedures are required due to deterioration of a previous repair. These procedures carry additive risks of mortality and morbidity.

Flow characterization of the ADVANTAGE and St. Jude Medical bileaflet mechanical heart valves.

Background And Aim Of The Study: The study aim was to characterize time-dependent flow fields and flow structures within the ADVANTAGE (ADV) and St. Jude Medical (SJM) prosthetic bileaflet mechanical heart valves.

Methods: Three-dimensional unsteady computational fluid dynamic simulations were conducted in the aortic position for both valves.

An in vitro assessment by means of laser Doppler velocimetry of the medtronic advantage bileaflet mechanical heart valve hinge flow.

Objective: The aim of this study was to evaluate the hinge flow field characteristics of the Medtronic Advantage bileaflet valve and compare them with the flow fields of the St Jude Medical standard valve. The present study provides laser Doppler velocimetry results for the Advantage and St Jude Medical valves to make a direct comparison of the flow fields of the 2 valve designs. This study aids in determining the preclinical efficacy of Medtronic's new bileaflet valve hinge design.

A numerical simulation of mechanical heart valve closure fluid dynamics.

A computational fluid dynamics model for the analysis of the bileaflet mechanical heart valve closure process is presented. The objective of the study is to demonstrate the ability of the numerical model to simulate the leaflet motion during the closing phase in order to investigate the closure fluid dynamics and to evaluate the effect of alterations in the leaflet tip geometry. The model has been applied to six different combinations of the leaflet tip geometry and the gap width between the leaflet tip and the housing.