Theoretical neuroscience: modeling the activation mechanism of potassium channels in neurons

We have modeled the electrostatic interaction between the S4 segment of the potassium channel molecule and the surrounding water molecules on both the intracellular and extracellular sides of the neural axon cell membrane. Two methods were used to approximate this interaction: (i) a macroscopic evaluation in which the water was treated as a dielectric medium with dielectric constant 80; (ii) a microscopic evaluation considering the effects of each individual water molecule fixed in position within the water pockets surrounding the S4 segment. The potential energy of the S4 due to the water pockets was plotted against the rotation of the S4 segment, while keeping the water pockets in their fixed positions. Although the two methods gave some differing results, both methods produced single well potential energy curves of ~6-9 eV depth. Based on this energy curve, we show that other forces on the S4 must create an effective torsional spring force with spring constant k~3-5 eV in order to produce a two well potential energy curve in qualitative agreement with experimental data

PHYSICAL ACTIVITY–INDUCED NEUROPROTECTION IN PARKINSON’S DISEASE IS MEDIATED BY NEUROTROPHIC FACTORS

Parkinson’s disease (PD) is a progressive neurological movement disorder manifested by motor and non-motor disturbances that are brought about by degeneration of dopaminergic (DAergic) neurons in the substantia nigra (SN), causing a decline in dopamine (DA) levels in the striatum. Pharmacological and surgical treatment of PD are often ineffective, cause severe side effects, and the benefits seen decrease with disease progression; therefore, there is a need to seek new therapies. Physical activity (PA), which includes exercise, is able to improve many systems in the body, including motor and cognitive function, and may serve as a viable option for remedy of PD. Due to many limitations, human studies are unlikely to explain whether such intervention may be neuroprotective in PD patients; therefore, the use of animal models is imperative. PA in animal models of PD has neuroprotective effects on DAergic neurons and current hypotheses infer a central role of neurotrophic factors (NTFs); however, the exact mechanisms of their action have yet to be elucidated. In the present review, studies will be discussed that highlight how PA increases NTF mobilization leading to protection of DAergic neurons and improved motor performance. Furthermore, this review will explore NTF influence in several postulated aberrant cellular processes where intervention could be made to treat PD, including neuroplasticity and synaptic transmission, angiogenesis and vasodilation, mitochondrial dysfunction through oxidative stress and protein aggregation, and neuroinflammation

Improving the Aesthetic and Environmental Quality of Your Farmstead by Landscaping

This presentation will review some basic landscape design principles, plant material selection, and benefits of landscaped windbreaks/vegetative barriers for your farmstead from a previous talk at the 2008 Cornbelt Cow/Calf Conference. This talk will also delve further into the aesthetic and living quality issues; with the addition of enhanced air quality improvement by planting a landscaped vegetative buffer on a farmstead or animal confinement area. There will be illustrations and examples for each topic

Trout Movements in a Small Mountain Stream

Five groups of 400 hatchery rainbow trout, (Salmo gairdneri), were stocked in a small, mountain stream at )-week intervals from June to September, 1972. A fish trap captured any fish moving out of a 500 m study section. Fish began moving at high levels during the first day of each stocking and continued at high rates for 5-8 days (Early Phase), after which movement decreased to low levels for 6-9 days (Late Phase). Early Phase fish moved primarily at night, possibly due to their disoriented state and high subjectivity to stream conditions. Fish moving during Late Phase did so mainly during daylight, probably in response to diurnal periodicity of a day-active food organism in the drift. Forced movement due to social behavior did not seem to be an influencing factor, but the duration of visible light seemed important to moving fish

Strategies for Optimizing Nitrogen Use in Corn with and without Subsurface Drainage

Excessive soil moisture can impact planting date, plant establishment, and N availability, resulting in reduced yields and N use efficiency. Nitrogen management practices such as use of urease and nitrification inhibitors, and split applications may be used to reduce N lost during the growing season, improving N use efficiency and crop productivity. The objective of this study was to determine whether N management practices could improve corn (Zea mays L.) productivity with or without subsurface drainage on a fine-textured clay soil in eastern North Dakota. Five field trials were conducted in 2009 and 2010 in eastern North Dakota. Treatments consisted of a factorial combination of N management practices [urease inhibitor n-(n-butyl) thiophosphoric triamide (NBPT), starter fertilizer, nitrification inhibitor 2-Chloro-6-(trichloromethyl) pyridine (nitrapyrin), and split applications], N rates (56, 112, 168, and 224 kg N ha-1), and the presence of subsurface drainage (two environments). In both 2009 and 2010 there was no grain yield differences among drainage treatments. Differences in grain yield were observed with different N rates. Nitrogen management practices also affected grain yield. The interactions between N management practices and drainage were not significant. End of season stalk nitrate content showed differences in N availability with different N rates, but not N management practices. Neither NBPT nor the starter fertilizer significantly increased yield over the untreated check in any environment. Nitrapyrin significantly increased yield over the untreated check at Fargo in 2010. Increased N rates resulted in greater corn grain protein

An investigation of fuel cell electrode activity influenced by alternating current electric fields

Two methods of applying an alternating current electric field to the grid electrodes of the fuel cell systems were studied. Both methods were used to enhance the power output of the system. The alternating current electric field was applied to the grid electrodes to induce greater ionic motion, reduce the concentration polarization losses due to the ionic film double layer, and to desorb catalyst poisons and strongly adsorbed ions from the fuel cell electrode sur­faces. The enhancement of the fuel cell system power was found to be a function of the applied voltage and frequency. A greater, applied alternating field voltage resulted in an increased power enhancement. In the first method, a maximum enhancement of 42,000 percent, at an applied voltage of 0.3 volt, was asymptotically approached as the frequency of the alternating current field was increased from 0.5 to 1000 cycles per second. This maximum enhancement corresponded to an output power of 3,000 microwatts. The input power from the alter­nating field was determined to be no greater than .3,000 microwatts. Also, a retention of the power enhancement for a short period after the removal of the applied alternating field was noticed and measured. In the second method, a maximum enhancement of 670 percent was obtained at an applied voltage of 0.3 volt and a frequency of three cycles per second. A power input of 9,000 microwatts was needed to obtain the 670 percent enhancement. This" power input was much greater than the enhanced power output obtained from the fuel cell system. Grid electrodes were positioned in the gas phase behind the fuel cell electrodes and initial studies indicated that such a con­ figuration consumed negligible input power while still producing an enhanced fuel cell power output. When the effects of the semiconductive materials were investi­ gated, a wafer of n-type silicon was used as the hydrogen electrode and a p-type silicon wafer was used as the oxygen electrode. The open circuit voltage of this configuration was 7.0 millivolts. An open circuit voltage of 4.5 millivolts was measured when the hydrogen electrode was p-type silicon and the oxygen electrode was n-type silicon. The difference between the two configurations indicated that, by assembling the fuel cell system in the same manner as the first configuration considered, an increase in open circuit voltage may be achieved

THE EFFECT OF DIETARY PROTEIN AND FEED SIZE ON THE ASSIMILATION EFFICIENCY OF STARLINGS AND BLACKBIRDS

Starlings (Sturnus vulgaris) were fed 3 feed sizes and 3 protein levels of swine feeds to determine metabolizable energy and assimilation efficiency. Metabolizable energy (12 kcal/g of diet consumed) and assimilation efficiency (3296 of gross energy intake) were independent of feed size. A 46% crude protein diet was 5196 assimilated and yielded more energy per gram of diet consumed than a 2196 crude protein diet which was only 35% assimilated. Starlings failed to maintain their body weight on a cracked corn diet containing 14% crude protein. Feeding behaviors of starlings due to their assimilation efficiencies are discussed and contrasted with the feeding behaviors sad assimilation efficiencies of Icterine blackbirds