Deg Intervals Research Articles

Increased Ankle Plantar Flexor Stiffness Is Associated With Reduced Mechanical Response to Stretch in Adults With CP

Hyperexcitable stretch reflexes are often not present despite of other signs of spasticity in people with brain lesion. Here we looked for evidence that increased resistance to length change of the plantar flexor muscle-fascicles may contribute to a reduction in the stretch reflex response in adults with cerebral palsy (CP). A total of 17 neurologically intact (NI) adults (mean age 36.1; 12 female) and 13 ambulant adults with CP (7 unilateral; mean age 33.1; 5 female) participated in the study. Subjects were seated in a chair with the examined foot attached to a foot plate, which could be moved by a computer-controlled electromotor. An ultrasound probe was placed over the medial aspect of the leg to measure the length of medial gastrocnemius muscle fascicles. Slow (7 deg/s) and fast (200 deg/s) stretches with amplitude 6 deg of the plantar flexors were applied over an ankle range of 70 deg at 10 deg intervals between 60 and 130 deg plantarflexion. It was checked by EMG electrodes that the slow stretches were sufficiently slow not to elicit any activity and that the fast stretches were sufficiently quick to elicit a maximal stretch reflex in both groups. The torque elicited by the stretches was measured together with changes in the length of medial gastrocnemius muscle fascicles. Muscle fascicles increased significantly in length with increasing dorsiflexion position in both populations (p < 0.001), but the fascicles were shorter in the CP population at all positions. Slow stretches elicited significantly larger torque and significantly smaller length change of muscle fascicles as the ankle joint position was moved more towards dorsiflexion in CP than in NI (p < 0.001). Fast stretches elicited larger torque responses at ankle joint positions of 80–100 deg in the NI than in the CP group (p < 0.01). A significant negative correlation was observed between the torque response and muscle fascicle length change to slow stretch in CP (p < 0.05), but not in NI. These findings support that increased passive resistance of the ankle plantar flexor muscle-tendon unit and development of contractures may conceal stretch reflex response in adults with CP. We argue that this should be taken into account in the neurological examination of spasticity.

An Online Active Balancing Method Using Magnetorheological Effect of Magnetic Fluid

The improvement of machining efficiency and precision puts forward new requirements for the balancing performance of machine tool spindle. Work piece quality can be effectively improved by implementing the active balance on the spindle. In this paper, a new active balancing method using magnetorheological (MR) effect of magnetic fluid is proposed. The mechanism of forming compensation mass by changing the distribution of magnetic fluid under local magnetic field is expounded. Experiments are carried out to verify the feasibility of the proposed method. Profile lines of magnetic fluid surface shape at different positions are measured with linear laser projection measurement method in experiments. Three-dimensional (3D) surface shape of the magnetic fluid is reconstructed by the synthesis of the measured profile lines. Experiments demonstrate that mass center of the magnetic fluid increases with the strength of magnetic field. Thus, the feasibility of the proposed method is verified experimentally. In order to weaken the vibration of machine tool spindle using this method, a balancing device is designed, which includes magnetic fluid chambers and three conjugated C-type electromagnets arranged at 120 deg intervals. For each electromagnet, the relationship among compensation mass (the corresponding balancing mass), excitation current, and rotation speed is established. Also, the performance of the balancing device is further proved in experiments conducted on the experimental platform. The imbalance vibration amplitude of the test spindle decreased by an average of 87.9% indicates that the proposed active balancing method in this paper is promising.

Rotordynamic Behavior of 225 kW (300 HP) Class PMS Motor–Generator System Supported by Gas Foil Bearings

This paper presents the dynamic behavior of a 225 kW class (300 HP), 60,000 rpm, permanent magnet synchronous (PMS) motor–generator system supported on gas foil bearings (GFBs). The rotor of a 225 kW PMS motor is supported by two identical gas foil journal bearings (GFJBs) and one pair of gas foil thrust bearings (GFTBs). The total weight and axial length of the coupled rotors are 272 N and 1042 mm, respectively. During the speed-up test to 60,000 rpm, unexpected large subsynchronous rotor motions appear at around 120–130 Hz above 35,040 rpm. After disassembling the motor, an inspection of the top foils of the GFJBs reveals significant rotor rubbing. Thus, the GFJBs are redesigned to have a smaller load capacity by reducing their axial length to 45 mm. In addition, three 50 μm thick shims are installed in the GFJBs at 120 deg intervals for reducing the swirl speed of air and producing bearing preloads. The modification delays the onset speed of subsynchronous motions to 43,200 rpm and decreases the amplitude of the subsynchronous motions from 20 to 15 μm. These results indicate that the modification improves the stability margin of the high-speed rotor system with increasing stiffness and damping. In addition, the logarithmic decrement trends are in good agreement with the test results.

Plasticity of spatial hearing: behavioural effects of cortical inactivation

The contribution of auditory cortex to spatial information processing was explored behaviourally in adult ferrets by reversibly deactivating different cortical areas by subdural placement of a polymer that released the GABAA agonist muscimol over a period of weeks. The spatial extent and time course of cortical inactivation were determined electrophysiologically. Muscimol-Elvax was placed bilaterally over the anterior (AEG), middle (MEG) or posterior ectosylvian gyrus (PEG), so that different regions of the auditory cortex could be deactivated in different cases. Sound localization accuracy in the horizontal plane was assessed by measuring both the initial head orienting and approach-to-target responses made by the animals. Head orienting behaviour was unaffected by silencing any region of the auditory cortex, whereas the accuracy of approach-to-target responses to brief sounds (40 ms noise bursts) was reduced by muscimol-Elvax but not by drug-free implants. Modest but significant localization impairments were observed after deactivating the MEG, AEG or PEG, although the largest deficits were produced in animals in which the MEG, where the primary auditory fields are located, was silenced. We also examined experience-induced spatial plasticity by reversibly plugging one ear. In control animals, localization accuracy for both approach-to-target and head orienting responses was initially impaired by monaural occlusion, but recovered with training over the next few days. Deactivating any part of the auditory cortex resulted in less complete recovery than in controls, with the largest deficits observed after silencing the higher-level cortical areas in the AEG and PEG. Although suggesting that each region of auditory cortex contributes to spatial learning, differences in the localization deficits and degree of adaptation between groups imply a regional specialization in the processing of spatial information across the auditory cortex.

Human phase response curve to a 1 h pulse of bright white light

The phase resetting response of the human circadian pacemaker to light depends on the timing of exposure and is described by a phase response curve (PRC). The current study aimed to construct a PRC for a 1 h exposure to bright white light (∼8000 lux) and to compare this PRC to a <3 lux dim background light PRC. These data were also compared to a previously completed 6.7 h bright white light PRC and a <15 lux dim background light PRC constructed under similar conditions. Participants were randomized for exposure to 1 h of either bright white light (n=18) or <3 lux dim background light (n=18) scheduled at 1 of 18 circadian phases. Participants completed constant routine (CR) procedures in dim light (<3 lux) before and after the light exposure to assess circadian phase. Phase shifts were calculated as the difference in timing of dim light melatonin onset (DLMO) during pre- and post-stimulus CRs. Exposure to 1 h of bright white light induced a Type 1 PRC with a fitted peak-to-trough amplitude of 2.20 h. No discernible PRC was observed in the <3 lux dim background light PRC. The fitted peak-to-trough amplitude of the 1 h bright light PRC was ∼40% of that for the 6.7 h PRC despite representing only 15% of the light exposure duration, consistent with previous studies showing a non-linear duration–response function for the effects of light on circadian resetting.

Identified antennular near-field receptors trigger reflex flicking in the crayfish

Near-field disturbances in the water column are known to trigger reflex antennular flicking in the crayfish Procambarus clarkii. We have identified the hydrodynamic sensors on the lateral antennular flagellum that constitute an afferent limb of this reflex and have measured the relative directionally dependent thresholds of the sensory neurons associated with these structures to hydrodynamic stimulation. Twenty-five individual standing feathered sensilla, comprising a sparse, linearly arrayed population of near-field sensors along the lateral and medial antennular flagella, were exposed to standardized pulsatile stimuli at 20 deg intervals along a 320 deg circular track. The results indicate that the sensilla are most sensitive to such stimulation in the plane of the flagellar axis. Identification and mechanical stimulation of single feathered sensilla in some preparations consistently evoked a flick reflex at maximal response latency, indicating that these sensors constitute at least one afferent limb for the reflex behavior. Experiments in which response latencies were measured following mechanical stimulation of truncated flagella, and were compared with the latencies in respective intact flagella, suggest that summation of inputs from the feathered sensillar pathways generates reflex flicking at minimal latencies. We discuss the possible central mechanisms that may underlie detection of critically important signals from this population of highly sensitive, inherently noisy sensors.

409 補助人工心臓用アキシャル型磁気軸受の最適化に関する研究(OS5-(3)オーガナイズドセッション《ライフサポートにおける工学技術》)

Many groups in the world are trying to develop many kinds of artificial heart for severe heart failure patients. We adopted a magnetically suspended motor which contributes device durability and better blood compatibility for the ventricular assist device (VAD). The influence that the size of permanents into the magnetic bearing system gave to the bearing performance was examined in detail by using the numerical magnetic field analysis. The double-bias hybrid magnetic bearing consists of four electromagnets located 90 deg intervals, three ring-shaped permanent magnets and a yoke. The results of numerical analysis show that the size of permanents in the same direction as flux path affects the bearing performance greatly. The comparison between numerical analysis and experiment results indicates to establish design parameter of double-bias hybrid magnetic bearing.

Simulation results of a hexahedron-octahedron based spherical stepping motor

The simulation results of a novel stepping motor based on a pair of a regular hexahedron and a regular octahedron (call “6-8 spherical stepping motor” afterward) are presented. The 3D electromagnet and motion coupled simulation program “Magnet 6” is used for the simulation. As the conditions of simulation, the excitation current and frequency is 1 A and 5.3 Hz, respectively. Three phase sinusoidal excitation currents are applied to two pairs of three coils of the stator individually at 120 deg intervals. The simulation results show that the rotor rotates along the rotating magnetic field and the output torque is 0.04 Nm. The simulation results prove the correctness of the 6–8 spherical motor driving method. The developed 6–8 spherical stepping motor is air-core type without back yoke for avoiding the cogging torque. When using iron core with back yoke, the proposed motor will be a high-torque spherical motor. The 6–8 spherical stepping motor was tested and the experimental results were compared with the simulation results. Then, the simulation program was used for optimum design of the 6–8 spherical stepping motor.

The electron drift velocity, ion acoustic speed and irregularity drifts in high-latitude E-region

Abstract. The purpose of this study is to examine the STARE irregularity drift velocity dependence on the EISCAT line-of-sight (los or l-o-s) electron drift velocity magnitude, VE×Blos, and the flow angle ΘN,F (superscript N and/or F refer to the STARE Norway and Finland radar). In the noon-evening sector the flow angle dependence of Doppler velocities, VirrN,F, inside and outside the Farley-Buneman (FB) instability cone (|VE×Blos|&gt;Cs and |VE×Blos|&lt;Cs, respectively, where Cs is the ion acoustic speed), is found to be similar and much weaker than suggested earlier. In a band of flow angles 45°&lt;ΘN,F&lt;85° it can be reasonably described by |VirrN,F|∝AN,FCscosnΘN,F, where AN,F≈1.2–1.3 are monotonically increasing functions of VE×B and the index n is ~0.2 or even smaller. This study (a) does not support the conclusion by Nielsen and Schlegel (1985), Nielsen et al. (2002, their #[18]) that at flow angles larger than ~60° (or |VirrN,F|≤300 m/s) the STARE Doppler velocities are equal to the component of the electron drift velocity. We found (b) that if the data points are averages over 100 m/s intervals (bins) of l-o-s electron velocities and 10 deg intervals (bins) of flow angles, then the largest STARE Doppler velocities always reside inside the bin with the largest flow angle. In the flow angle bin 80° the STARE Doppler velocity is larger than its driver term, i.e. the EISCAT l-o-s electron drift velocity component, |VirrN,F|&gt;|VE×Blos|. Both features (a and b) as well as the weak flow angle velocity dependence indicate that the l-o-s electron drift velocity cannot be the sole factor which controls the motion of the backscatter ~1-m irregularities at large flow angles. Importantly, the backscatter was collected at aspect angle ~1° and flow angle Θ&gt;60°, where linear fluid and kinetic theories invariably predict negative growth rates. At least qualitatively, all the facts can be reasonably explained by nonlinear wave-wave coupling found and described by Kudeki and Farley (1989), Lu et al. (2008) for the equatorial electrojet and studied in numerical simulation by Otani and Oppenheim (1998, 2006).

3D spatial sampling with a cylindrical multibeam sonar array

Various beam pair combinations can be formed with cylindrical multibeam sonar arrays to obtain a 3D spatial sampling of a patch of seafloor for each ping. This capability is explored with a 286 deg sector cylindrical array transmitting a stepped FM pulse over a 243 deg vertical fan beam centered on nadir and receiving with twenty-seven beam pairs, symmetrically steered about nadir in the fore-aft direction and spaced at 7.16 deg intervals across track. Conventional conjugate product techniques yield two across-track profiles of 26 soundings each (52 phasors total) per ping. However, by combining one or two phasors along-track and one, two or three phasors across-track, soundings can be obtained at the spatial bisectors of the angles between the 52 phasors. This yields three profiles consisting of 51 soundings each, for a total of 153 soundings. This effectively creates a 3D patch of detected seafloor for each ping, which may overlap with the patches from adjacent pings depending on the sonars attitude changes and altitude above the seafloor. [Work supported by NRL-SSC grant N00173-00-1-G912 and NOAA grant NA170G228.]

Isosteric Heat of Adsorption of Water Vapor on Bismuth Iron Molybdate Measured by the Method of Constant Surface Conductance

The sensitivity of the four-probe electrical conductance of compressed Bi3FeO4(MoO4)2 powder to humid air was measured under isothermal conditions from 24 to 60 °C at 4 deg intervals. The data were analyzed as the logarithm of the conductance change due to humid air vs the logarithm of the humidity. This was done under quasistatic conditions, so that in the oven chamber the adsorbed surface water was always in equilibrium with the vapor in the air. From this, a series of isoconductance curves were calculated at a number of distinct values. Plotted as the logarithm of the absolute humidity vs 1000 K/T these curves were good fits to a straight line, and via the Clausius−Clapeyron equation gave the isosteric heats of adsorption. The results showed hydrophobic behavior with latent heats ranging from about 0.2 eV (19 kJ/mol, most likely due to single isolated hydrogen bonds) for a very dry surface up to the bulk-water value of 0.45 eV (44 kJ/mol, due to water molecule clustering) for surfaces exposed to high humidity. Previous analysis has shown that the number of layers of adsorbed water varies from one to four for this material, with a conductance change increase measured over 3−4 orders of magnitude.

Orientation contrast vs orientation in line-target detection

This study concerns the roles of absolute and relative orientation in determining detectability of a line-element target in a background field of uniformly oriented line elements. Target detectability was determined as a function of background-field orientation, sampled at 5 deg intervals, for three levels of orientation contrast—the difference between target and background orientations—sampled at 10, 20 and 30 deg. Stimulus displays were presented briefly and followed by a mask. There were 10 observers, whose detection performance was quantified by the discrimination index d′ from signal detection theory. Target detectability was found to depend both on absolute orientation, represented by background-field orientation, and on orientation contrast. At each level of orientation contrast, performance was best when the background field, not the target element, was vertical or horizontal. These data are difficult to explain by general models of orientation discrimination based on simple orientation opponency between local line-sensitive filter units; three other models specifically concerned with target detection are briefly considered.

Selecting conditions of preparation of copper-based melts for spraying

The chemical heterogeneity of copper and its alloys in respect of certain elements in relation to the thermal and time conditions of melting and the effect of the type of deoxidizing agent on the content of oxygen and nonmetallic inclusions were examined on rapidly cooled cylindrical specimens 4-6 mm in diameter produced by sucking the liquid metal into quartz tubes at specific periods in melting, followed by rapid cooling in water. Metal samples were taken from laboratory and industrial melts of copper and its alloys in induction furnaces with a capacity of 65-1000 kg using graphite crucibles. The charge was represented by M0 grade copper (cathodes, waste from elctrotechnical industry: pressings, conductors, powder blanks, etc.), grade TsO zinc (Tsl), grade SO (SI) lead, grade Ol (02) tin. Deoxidation was carried out with a 0.02-0.10% copper--phosphorus (MF-10) and copper-boron (2% boron) master alloy. To reduce the extent of gas absorption, all the melts were covered with a dried charcoal layer 60-120 mm thick. The deoxidizing agent was added after melting copper. This was followed by adding alloying elements, with tin added last. Samples of the melts to be used for further dispersion by water to produce nonspherical powders were taken at temperatures of 1180-1280 (copper), 1100-1220 (L80 brass), and I080-I150°C (BrOTsS bronze) in 20 deg intervals. The holding time at each temperature was 10-30 min. Sections were prepared from the cylindrical specimens. The degree of homogeneity of the distribution of the solute and alloying elements was analyzed in Superprobe-733 equipment, the oxygen content was estimated in a device manufactured by Balzers Company, the number of nonmetallic inclusions in Quantimet equipment, and the volume fraction of the inclusions was calculated in measuring 500 fields of view on each section. The results show that the degree of chemical heterogeneity of the copper melt greatly decreases after thermal treatment at 1250°C with holding for 20 min, and that of the melts of brass and bronze decreases after treatment at 1180 and I130°C and holding for 15 and 20 min, respectively. Figure 1 shows the concentration curves of the maximum and minimum values of microheterogeneities in respect of the solid and alloying elements for copper, brass, and bronze. As an example, Tables 1 and 2 give the average results of examination of the effect of the oxidizing agents (phosphorus and boron) on the content of oxygen and nonmetallic inclusions in OTsS 5-5-5 bronze. It can be seen that boron results in lower oxygen concentration than phosphorus. When the boron concentration is increased to 0.06% the amount of oxygen rapidly decreases. A further increase of the boron concentration is less effective and the fraction of spherical powder particles increases. This impairs the technological processes of the powder. Subsequent addition of zinc to the melt results in an additional reduction of the oxygen concentration. The content of the nonmetallic inclusions decreases on adding both deoxidizing agents, but in deoxidation with boron a subsequent addition of zinc to the melt is not accompanied by an increase of the volume fraction of the inclusions.

Heat Transfer From Two Elliptic Cylinders in Tandem Arrangement

An experimental investigation has been conducted to clarify heat transfer characteristics of two elliptic cylinders having an axis ratio 1:2. They were placed in tandem arrangements and their angles of attack to the upstream uniform flow were identical. The testing fluid was air and the Reynolds number based on the major axis length c ranged from about 15,000 to 80,000. The angle of attack was varied from 0 to 90 deg at 30 deg intervals and the nondimensional cylinder spacing l/c from 1.25 to 4.0, where l denotes the streamwise distance between the cylinder centers. It has been found that the heat transfer features vary drastically with the angle of attack and also with the cylinder spacing.

The kinetics of the thermal degradation of calcium carbonate

The decomposition of calcium carbonate fine powder in a flowing nitrogen atmosphere has been investigated by non-isothermal thermogravimetry at heating rates in the range, 10–50 deg min−1. The analog percentage weight change record was digitized at 1 deg intervals. The resulting data, transformed into dimensionless extents of reaction and calculated rates of reaction, was then subjected to the Arrhenius, Friedman and Generalized Kissinger analyses, using a recently developed FORTRAN program system. The value ofn namely 0.39 ±0.04, resulting when the data is analyzed assuming an nth order reaction, strongly indicates that the most probable rate controlling step is a three-dimensional diffusion process (D4 mechanism), withE=172.4 kJ·mol−1 andA=1.97·104 K−1·min−1. Reasons for the wide disparity in previously reported kinetic data are discussed.

Subjective vertical before and after space flight

Three scientist astronauts on the D1 spacelab mission participated in a series of orientation experiments before and after exposure to orbital weightlessness. Each subject was tilted about a roll axis at 15 deg intervals up to +/-90 deg. At each angle the subject set a luminous line to what he perceived to be the vertical. The results of these tests are presented.

An Axial Flow Research Compressor Facility Designed for Flow Measurement in Rotor Passages

An axial-flow research compressor facility, which is designed for relative flow measurement, is described in this paper. The facility has a rotating-probe traverse mechanism which is capable of traversing hot-wire, pilot and other probes at 0.09 deg intervals across the rotor blade passage. The data transmission system includes rotating transducers, pressure transfer device, ten-channel mercury slip-ring unit, scanivalve, etc. The instrumentation includes on-line data processing capability. A brief description of probes used as well as some typical data on the rotor blade static pressure, rotor endwall flow, and rotor wake characteristics are given in the paper.

Letter: Free radicals in pyrimidines: e.s.r. of x-irradiated single crystals of phenobarbital.

Two crystal polymorphs of phenobarbital, of melting points 175 deg C and 17# deg C, were x-irradiated in air at room temperature with doses of 10 Mrads. ESR spectra were recorded at 5 deg intervals about each of 3 orthogonal axes at both 9.3 GHz and 22.5 GHz. A comparative table is preserted of the ESR data obtained from the two crystal structures. The results were essentially the same, except that the relative values of the proton hyperfine couplings were different because of the different ethyl group rotations about the bond to C(5). It is tentatively suggested that one factor important to the mechanism of radical formation in this group of compounds is the difficulty in reorienting a large group into the plane of the pyrimidine ring when the electronic configuration of C(5) goes from sp/sup 3/ in the undamaged molecule, to sp/sup 2/ in the free radical. It is also suggested that another factor to be considered is the relative stability of alternate radical structures. (UK)

Acid-base equilibria of some naphthoic acids, studied spectrophotometrically

Abstract The dissociation constants (Ka), inaqueous solution, of 1 -naphthoic, 2-naphthoic, 2-methyl-1-naphthoic and 2,3-dimethyl-1-naphthoic acids have been determined at 5 deg intervals over the temperature range 288–313°K. The quantities -log Ka, ΔG° ΔH° and ΔS° have been calculated at each temperature and the pKa, values are considered in relation to those of alkyl substituted benzoic acids.

Quantum oscillations in the attenuation of transverse ultrasonic waves in field-cooled chromium

Quantum oscillations in the attenuation of 300 MHz transverse ultrasonic waves have been measured at 1·2°K in single crystals of chromium which were previously cooled through the Neel temperature in the presence of a 55 kG magnetic field directed along one of the [100] crystalline axes (field-cooling). Frequencies of the quantum oscillations were determined at 5 deg intervals in each of two major planes by computer analysis of the data between 38 and 49 kG. The variation of quantum oscillation frequencies as the relative angle between the measuring field direction and crystalline axes varied was found to be consistent with the picture that field-cooling produces a single antiferromagnetic domain state and showed that the Fermi surface of chromium is considerably altered by the onset of antiferromagnetism. Several quantum oscillation frequencies have values equal to integral multiples of one particular frequency branch. Other branches appear to have frequencies equal to the sums of pairs of lower frequencies. Discussion of these results is presented.