Inclined Plane Method Research Articles

Safety analysis of slipping barefoot on marble covered wet areas

This study was conducted in order to determine the suitable surface processing techniques which will increase the safety of pedestrians, reducing the risk of slipping on wet floor coverings on which they walk barefoot. In the scope of the study, slip angle of surface-processed marbles in three different dimensions is determined by using DIN 51097 Standard “The determination of the characteristics that reduce slipping on wet, barefoot surfaces”. Slip angles were calculated with the help of an inclined plane method and by using three different surface processing techniques (polishing, honing and tumbling techniques) for five different types of marble. It was found that the parameters which affected slip angle values of the marbles were surface roughness, plate sizes, grain size of the abrasives used for surface processing, physical and mechanical properties. Statistical analysis was used to determine the relationship between these parameters. The marbles were then grouped according to safe utilization places depending on slip angle and surface roughness, according to the statistical results.

Greatly improved neurological outcome after spinal cord compression injury in AQP4-deficient mice

Aquaporin-4 (AQP4) is a water channel protein expressed in astrocytes throughout the CNS. In brain, AQP4 facilitates water balance and glial scar formation, which are important determinants of outcome after injury. Here, we provide evidence for AQP4-dependent spinal cord swelling following compression injury, resulting in remarkably improved outcome in AQP4-null mice. Two days after transient T6 spinal cord compression injury, wild-type mice developed more severe hindlimb weakness than AQP4-null mice, as assayed by the Basso open-field motor score, inclined plane method and footprint analysis. Basso motor scores were 1.3 +/- 0.5 (wild-type) versus 4.9 +/- 0.6 (AQP4-null) (SE, P < 0.001). Improved motor outcome in AQP4-null mice was independent of mouse strain and persisted at least 4 weeks. AQP4-null mice also had improved sensory outcome at 2 days, as assessed by spinal somatosensory evoked responses, with signal amplitudes approximately 10 microV (uninjured), 1.7 +/- 0.7 microV (wild-type) and 6.4 +/- 1.3 microV (AQP4-null) (P < 0.01). The improved motor and sensory indices in AQP4-null mice corresponded to remarkably less neuronal death and myelin vacuolation, as well as reduced spinal cord swelling and intraparenchymal spinal cord pressure measured at T6 at 2 days after injury. AQP4 immunoreactivity at the injury site was increased in grey and white matter at 48 h. Taken together, our findings indicate that AQP4 provides a major route for excess water entry into the injured spinal cord, which in turn causes spinal cord swelling and elevated spinal cord pressure. Our data suggest AQP4 inhibition or downregulation as novel early neuroprotective manoeuvres in spinal cord injury.

Leakage current suppression and resistance to tracking and erosion of HTV silicone rubber with added silicone plasticizer

The present study evaluated the leakage current suppression and the resistance to tracking and erosion of high-temperature vulcanized silicone rubbers (HTV-SIRs) containing different levels of silicone plasticizer. Slab HTV-SIRs unfilled and filled with alumina trihydrate (ATH, 50 wt%) and with added linear silicone plasticizer (0-6.0 wt%), which was terminated with hydroxyl groups and of which repetition number was 13-18, were tested. Evaluation using the IEC 60587 inclined-plane method indicated that the plasticizer had no influence on the tracking and erosion behavior. Salt-fog test results indicated that a higher level of plasticizer in the ATH-filled HTV-SIR showed smaller leakage current. Gas chromatography and mass spectrometry suggested that the enhanced suppression of the leakage current for ATH-filled HTV-SIR can be attributed to migration of the linear silicone plasticizer onto the surface contaminants. It was concluded that the addition of silicone plasticizer is useful for improving the leakage current suppression ability of HTV-SIR without reducing its tracking and erosion resistance in the above laboratory tests

Validation of the Skolnick method for slice thickness estimation

Objective: In 1991, Skolnick proposed a method for estimating ultrasound beam width in the elevation direction (slice thickness) using conventional quality assurance phantoms. The method involves imaging nylon filaments at 45 degrees to the image plane. Dedicated phantoms are also available for the estimation of slice thickness using an inclined plane method. The aim of this study was to attempt validation of the Skolnick method by comparison with the inclined plane method.

Leakage current monitoring and outdoor degradation of silicone rubber

The degradation process of silicone rubber was investigated by leakage current monitoring in the inclined-plane method. A data acquisition system (DAS) with 12-bit, 8-channel analog/ digital (AD) converter was prepared. The maximum erosion depth was measured for use as the degradation indicator. The result suggests that the discharge duration and current waveform are well corresponding with the degradation process. And fast Fourier transform (FFT) analysis from the stored waveform shows that the harmonic ratio I3/I1 corresponds with the initial surface transition from hydrophobic to hydrophilic, and with further progressive degradation. In addition, it may be possible to use cumulative charge and peak pulses as quantitative indicators of failure. Furthermore, the contact angle was adopted for assessing surface degradation. These results indicate that the surfaces are divided into top and bottom areas depending on the degree of exposure to dry band arcing. It seems that the bottom area subjected to most of the dry band arcing contains very short chains of silicone rubber as well as alumina trihydrate fillers, while the top area shows the loss of filler particles.

Determination of the Receding Contact Angle of Sessile Drops on Polymer Surfaces by Evaporation

The receding contact angles of water drops on PMMA and PET surfaces were determined by using video microscopy to follow the time-dependent evaporation of sessile drops. Depending on the initial drop size, receding angles of θr = 54−64° for PMMA and θr = 64−66° for PET were found with an average hysteresis of 23.5 ± 1.5 and 19.5 ± 1.5°, respectively. Advancing and receding angles, θa and θr, were also determined by the needle-syringe and the inclined plane methods for comparison. The discrepancies from the mean of the maximum and minimum contact angle results of both the needle-syringe and the inclined plane methods were larger than expected for all the polymer surfaces. A general trend was seen with samples giving a larger hysteresis also producing a larger discrepancy for all the samples. The major cause of this discrepancy is the variation of the rate of liquid introduction and withdrawal with the syringe in the needle-syringe method and the drop size effect in the inclined plane method. In this respect...

Experimental study on MRI evaluation of the course of cervical spinal cord injury.

An experimental study was conducted to evaluate MRI signal changes within the spinal cord after the injury in rats. To clarify the significance of MRI signal changes in the injured cervical cord. Tokyo, Japan. Cervical spinal cord injury was produced in rats by placing a 20-g, or 35-g weight on exposed dura at the C6 level for 5 min (20 g- or 35 g-compression group). Motor function was evaluated by the inclined-plane method at 2, 7 and 28 days after the injury. T1- and T2-weighted images were produced by the spin-echo method with a static magnetic field strength of 2.0 tesla, at 2 and 28 days after the injury, and then the histopathological examinations were performed. In the 20-g compression group, which recovered from the paralysis at 28 days, MR images were T1 iso signal/T2 high signal 2 days after the injury and T1 iso signal/T2 high signal after 28 days. The changes in MRI signal 2 and 28 days represented edema and gliosis, respectively. In the 35-g compression group, which incompletely recovered from paralysis at 28 days. MR images were T1 iso-signal/T2 low signal surrounded by high signal 2 days after the injury and T1 low/T2 high signal at 28 days. The MRI signal changes 2 and 28 days reflected hemorrhage with edema and cavities, respectively. T2 low signal of the spinal cord observed early after injury reflects hemorrhage and may serve as an indicator of a poor prognosis. T1 low/T2 high signals from the subacute to chronic period indicated persistence of paralysis and limited recovery of function.

Test Object for Measurement of Section Thickness at US

A simple phantom was used to test the ultrasound beam profile in the elevation direction (perpendicular to the scanning plane). Based on the inclined plane method, the phantom allowed direct clear display of the section thickness over the whole exploration depth on a single standard ultrasonographic image. This was demonstrated with one- and one and one-half-dimensional arrays. The results showed the efficiency of electronic focusing in the elevation plane associated with one and one-half-dimensional arrays.

The effect of the sodium channel blocker QX-314 on recovery after acute spinal cord injury.

There is evidence that elevated intracellular sodium ([Na+]i) activity potentiates spinal cord injury (SCI) and the hypoxic/ischemic cell death. In this study, we examined the effect of QX-314, a potent Na+ channel blocker, on recovery after SCI in vivo. QX-314 (2.0 and 10 nmol) or vehicle was microinjected (2 microL) into the injury site 15 min after SCI. Injury was performed by compression of the spinal cord at C7-T1 for 1 min with a modified aneurysm clip exerting a closing force of 35 g. Neurological function was assessed 1 day after injury and weekly thereafter until 6 weeks by the inclined plane method and by the modified Tarlov technique. After 6 weeks of injury, the origin of descending axons at the injury site was determined by retrograde labeling with fluorogold (FG), and a computer-assisted morphometric assessment of the injury site was performed. There was a significant improvement in counts of retrogradely labeled neurons in the red nucleus and rostral ventrolateral medulla (RVLM) in rats treated with either 2 nM (1338 +/- 366 and 28.8 +/- 16) or 10 nM (1390 +/- 511 and 46.3 +/- 31) QX-314 as compared to vehicle (902 +/- 403 and 13.8 +/- 8). There was a trend to increased neuronal counts in the sensorimotor cortex (170.8 +/- 226.8) and vestibular nuclei (1096.2 +/- 970.2) with QX-314 (10 nM) as compared to the vehicle-treated group. There was no significant difference in the extent of neurological recovery between the control and treated groups. Our results suggest that the Na+ channel blocker QX-314 partially preserves the integrity of descending motor axons after SCI. However, in this study, the effects were insufficient to result in sustained improvements in behavioral neurological function.

Effects of α-Phenyl-N-tert-butyl Nitrone (PBN) on Compression Injury of Rat Spinal Cord

α-Phenyl-N-tert-butyl Nitrone (PBN) is a free radical scavenger which recently has proved to be neuroprotective in experimental studies on focal cerebral ischemia and infarction. We therefore studied the effect of this drug in a model of moderate compression injury to rat spinal cord at the midthoracic level. The compound was given intraperitoneally 0.5 h before (100 mg/kg b.w) and at 1.5 h (50 mg/kg b.w) and 3.5 h (50 mg/kg b.w) after compression. Treated animals and controls (vehicle alone) were allowed to survive for 1 or 9 days following trauma. The functional outcome was tested by the inclined plane method and the motor performance score. By using MAP2 immuno-staining the number of nerve cell bodies in the ventral horn and the ratio of MAP2 immunostained area to area of whole section of the cord were assessed to detect loss of neurons and loss of dendrites in the compressed segment. pAPP and PGP9.5 immunostaining was used to demonstrate axonal lesions.Treated and control rats showed at day 1 when tested with the inclined plane method a marked reduction of the capacity angle. This abnormality recovered gradually over the following days and was normalized at day 9. The motor performance score showed a marked reduction at day 1 which almost normalized at day 9. There was no difference regarding the functional outcome between rats given PBN and controls in none one of these functional tests.The spinal cord of normal rats presented immunoreactivity to MAP2 in nerve cell bodies and dendrites but not in axons and other structures. Following compression there was at day 1 and 9 a marked loss of MAP2 immunoreactivity in dendrites and nerve cell bodies. We could not detect any difference between the PBN and the control rats regarding the degree of cell loss or degree of reduction of dendrite staining. No difference between the two groups was seen with the axonal immunostainings (βAPP and PGP9.5).In conclusion, our study did not reveal any neuroprotective effect of PBN on the functional outcome and morphology (immunostaining to MAP2, pAPP and PGP9.5) in this model of moderate compression trauma to rat spinal cord.

The relationships among the severity of spinal cord injury, residual neurological function, axon counts, and counts of retrogradely labeled neurons after experimental spinal cord injury

Substantial residual neurological function may persist after spinal cord injury (SCI) with survival of as few as 5–10% of the original number of axons. A detailed understanding of the relationships among the severity of injury, the number and origin of surviving axons at the injury site, and the extent of neurological recovery after SCI is of importance in understanding the pathophysiology of SCI and in designing treatment strategies. In the present study, these relationships were examined in rats with graded severity of clip compression injury of the cord at T1. The rats were randomly assigned to one of the following injury groups ( n = 5 each): normal (laminectomy only), 2-, 18-, 30-, 50-, and 98-g clip injuries. Neurological function was assessed by the inclined plane method and by the modified Tarlov technique. A morphometric assessment of axons at the injury site was performed by a computer-assisted line sampling technique. The origin of descending lions at the injury site was determined by retrograde labeling with horseradish peroxidase. The inclined plane scores varied as a negative linear function of the closing force of the clip used to inflict SCI( r = −0.93; P < 0.0001). The mean axon count was 367,000 ± 529,000 in normal rats and decreased as a negative exponential function of injury force ( r = −0.92; P < 0.0001). As well, SCI caused preferential destruction of large axons as reflected by the change in mean axon diameter from 1.74 ± 0.06 μm in normal cords to 1.46 ± 0.04 μm in injured cords (pooled mean for all injuries). Inclined plane scores varied logarithmically with the number of axons at the injury site ( r = 0.90; P < 0.001) and were highly correlated with the integrity of nonpyramidal tracts, in particular the rubrospinal ( R = 0.89), Vestibulospinal (r = 0.87), and raphespinal ( R = 0.84) tracts. These data demonstrate a precise relationship between the number of surviving axons at the injury site and residual neurological function and confirm the importance of nonpyramidal tracts in modulating gross motor performance.

Spinal cord restitution following compression injuries in rats.

Spinal cord compression injuries were produced in rats by applying weights to a plate 2.2 x 50 mm in size, placed on the exposed midthoracic dura covering the spinal cord. The influence of force and duration of compression was studied by using 3 different weights, 20, 35 and 50 g, applied for 1, 5 and 10 min. Postoperative neurological function was tested by the inclined plane method and the rats were observed for 3 weeks. Neurological impairment increased with force and duration of compression. It is therefore reasonable to conclude that patients suffering from spinal cord injury should be investigated immediately for signs of persistent cord compression. If this is present, early decompression might be of value, although nothing is known in man concerning the limits of force and duration of compression permitting postoperative neurological recovery.

Levallorphan and dynorphin improve motor dysfunction in mongolian gerbils with unilateral carotid occlusion: The first application of the inclined plane method in the experimental cerebral ischemia

Levallorphan and dynorphin were effective on the motor dysfunction in the gerbil model of unilateral cerebral ischemia. The effect of opioids, levallorphan (mixed agonist-antagonist), dynorphin (kappa-receptor agonist) and naloxone (mu-receptor antagonist), on neurological impairment was evaluated using the unilateral cerebral ischemia model of gerbil. Motor function was evaluated quantitatively by using the inclined plane method. Both levallorphan-treated group and dynorphin-treated group showed a significant improvement of the motor dysfunction compared with saline-control group. On the other hand, naloxone-treated group did not differ from saline-control group. The beneficial effect of these opioids on motor dysfunction might be mediated by the kappa-opioid receptor. This study also showed the potential usefulness of the inclined plane method for the investigation on the cerebral ischemia.

Treatment of experimental spinal cord injury with TRH, naloxone, and dexamethasone

Comparison of thyrotropin-releasing hormone (TRH), naloxone, and dexamethasone treatments in experimental spinal cord injury was studied in albino rats. Animals were made paraplegic by the application clip method of Rivlin and Tator. Treatment was administered intraperitoneally as a bolus injection in two doses at 45 and 120 minutes each after the injury. Animals were allocated randomly to one of four experimental treatment groups: (1) TRH (0.6 mg of TRH per dose) (2) naloxone (0.8 mg per dose), (3) dexamethasone (0.6 mg per dose), and (4) saline. Neurologic recovery was assessed by the inclined plane method, and cavitation size of the cord and of the pyramidal tract was examined under the light microscope. Results show that TRH and naloxone are therapeutically beneficial in the treatment of spinal cord injury, and that dexamethasone is ineffective.

Assessment of spinal cord injury by counting corticospinal and rubrospinal neurons

This paper describes an objective, quantifiable technique for assaying the degree of severity of spinal cord injury. Twenty-one rats underwent a C 7-T 1 laminectomy: 12 received a C 8 spinal cord clip compression injury with forces of either 2.3, 16.9 or 53.0 g; 4 had cord transection at C 8, and 5 had no cord lesion. Postoperative clinical neurological assessment was performed by the inclined plane method. At 4 weeks, the spinal cord-injured rats underwent a T 10 transection and insertion of a Gelfoam pledget impregnated with horseradish peroxidase (HRP). HRP was similarly administered to 9 normal rats. Longitudinal sections of the spinal cord encompassing the injury site were stained with Luxol fast blue, and coronal sections from the cerebrum and midbrain were processed for HRP reactivity with tetramethylbenzidine. Labelled corticospinal and rubrospinal neurons were counted in every 6th section to derive a cortical score (CS) and a red nucleus score (RNS) for each animal. The CS reflected the extent of the pathological changes at the site of cord injury and the In CS decreased linearly with increasing injury severity (P < 0.0001). In contrast, the RNS was only reduced in animals with severe (53.0 g) cord injuries (P < 0.0006). The degree of preservation of the dorsal columns including the corticospinal tracts at the injury site correlated with the CS, whereas the RNS was related to the degree of preservation of the lateral columns. Counts of rubrospinal neurons, but not corticospinal neurons, correlated closely (r = 0.96, P < 0.001) with the inclined plane results, suggesting the importance of non-pyramidal tracts in controlling gross motor function. Thus, counting corticospinal and rubrospinal neurons is an objective, reliable test of the severity of experimental spinal cord injury.

Role of monoamines in experimental spinal cord injury in rats. Relationship between Na+-K+-ATPase and lipid peroxidation.

A spinal cord injury was produced in Wistar rats by extradural compression of the cord with a Sugita aneurysm clip for 5 seconds. During a 2-week observation period following the injury, the tissue norepinephrine (NE), dopamine (DA), and serotonin (5-HT) concentrations decreased uniformly at and below the injured site. The chemical denervation of NE or 5-HT neurons produced by the intraspinal injection of 6-hydroxydopamine (6-OHDA) or 5,7-dihydroxytryptamine (5,7-DHT) 2 weeks before the injury did not cause a marked difference in the extent of hemorrhagic necrosis of the spinal cord after trauma as compared to control animals without pretreatment. In the rats pretreated with 6-OHDA, NE was decreased to less than 30% of control (non-pretreated) values, and, beginning at 5 days after injury, motor performance (assessed quantitatively with the inclined-plane method) was significantly improved compared to results in the non-pretreated control rats. The rats pretreated with 5,7-DHT showed no change from control animals. Spinal cord samples from non-pretreated control animals obtained at the injury site 30 minutes after the compression injury showed a marked decrease in the activity of synaptosomal Na+-K+-ATPase (adenosine triphosphatase) of about 50%, and an increase in both thiobarbituric acid reaction substance (about 170%) and cyclic guanine monophosphate (about 150%). The NE-denervated rats showed no significant changes in these three parameters. The results indicated that NE released after crush injury may impair the neuronal cell membrane around the lesion site by induction of lipid peroxidation. The possible mechanisms by which released NE may alter membrane function are discussed.

Effect of naloxone on functional recovery after experimental spinal cord injury in the rat

The effect of the opiate antagonist naloxone on the functional recovery of rats injured with a 10 g-cm impact to the spinal cord at the T-3 level is studied. Sixteen rats were treated with 0.8 mg of naloxone in an intraperitoneal bolus 45 and 120 minutes after injury, 16 rats were given 4 mL of saline instead of naloxone, and 16 rats were neither injured nor treated. To assess weekly the motor recovery of the injured animals, the inclined plane method was employed. After the 10-week assessment period, naloxone-treated animals showed a significantly better performance on the inclined plane than saline-treated animals. Naloxone may be useful for the treatment of spinal cord injury although its mechanism of action remains unknown.

Alpers and Mancall's essentials of the neurological examination, ed. 2

Comparison of thyrotropin-releasing hormone (TRH), naloxone, and dexamethasone treatments in experimental spinal cord injury was studied in albino rats. Animals were made paraplegic by the application clip method of Rivlin and Tator. Treatment was administered intraperitoneally as a bolus injection in two doses at 45 and 120 minutes each after the injury. Animals were allocated randomly to one of four experimental treatment groups: (1) TRH (0.6 mg of TRH per dose) (2) naloxone (0.8 mg per dose), (3) dexamethasone (0.6 mg per dose), and (4) saline. Neurologic recovery was assessed by the inclined plane method, and cavitation size of the cord and of the pyramidal tract was examined under the light microscope. Results show that TRH and naloxone are therapeutically beneficial in the treatment of spinal cord injury, and that dexamethasone is ineffective.

On the Measurement of Temperature Dependency of Adhesive Force of Powder Block by Inclined Plane Method

On the Measurement of Temperature Dependency of Adhesive Force of Powder Block by Inclined Plane Method

16—MEASUREMENTS OF THE INFLUENCE OF FINISHING AGENTS ON THE FRICTION OF FIBRES

ABSTRACT Experiments with continuous yarns, treated with a large variety of finishing agents, in which the coefficient of friction was measured by an inclined-plane method, yielded useful information on the properties of finishing agents on the one hand and also led to the development of a measuring technique for short fibres (30–40 mm). This method permits the determination from a 50 mg sample of fibrous textile material of the static as well as the dynamic coefficient of friction in such a way that reproducible results are obtained, the accuracy of the method being indicated by the very low coefficient of variation of the individual measurements. This method is based upon the formula ; the rubbing surface consists of fibres taken from the sample under test. It can be used by girls accustomed to routine testing work; the time taken for complete determination of coefficients of friction of a sample being about 90 minutes. The results obtained with finishes of various kinds on viscose staple fibre are described as well as a number of observations that bear upon the rheological phenomena of inter-fibre movement in general.