Negative Waveform Research Articles

Retinal Disease Expression in Bardet-Biedl Syndrome-1 (BBS1) Is a Spectrum from Maculopathy to Retina-Wide Degeneration

To define the retinal phenotype in patients with the Bardet-Biedl syndrome and mutations in the BBS1 gene. Ten patients (age range, 16-48 years), representing eight pedigrees, with BBS1 gene mutations were studied clinically and with kinetic perimetry, chromatic static perimetry, electroretinography (ERG), and optical coherence tomography. Of the 10 patients, 8 were M390R homozygotes and 2 were compound heterozygotes with one allele also M390R. A spectrum of retinal disease expression was present. The mildest disease was a subtle maculopathy with relatively limited peripheral retinal dysfunction. Moderate disease showed retina-wide rod > cone dysfunction, and often there was a negative ERG waveform. More severe disease expression had different patterns: either loss of central function but retained abnormal peripheral function or a retained small central island of impaired function only. Moderate and severe disease showed loss of retinal and photoreceptor layer thickness across wide expanses of retina. Severity differed in family members and was independent of age. In addition, severity was not explained by genotype at a recently reported BBS epistatic gene, MGC1203. The cardinal feature of retinal degeneration in BBS1 can show a wide spectrum of disease expression.

Wide operation margin of toggle mode switching for magnetic random access memory with preceding negative pulse writing scheme

In this work, a writing scheme with preceding negative pulse wave form for toggle magnetic random access memory (MRAM) is proposed to enhance the switching yield and enable a low current switching. The failure mechanism of toggle switching is studied by micromagnetic analysis. As a result of broadened operation window and reduced switching current, the scalability of MRAM is feasible with the robust toggle operation.

Sympathetic skin responses: the influence of electrical stimulus intensity and habituation on the waveform

Repeated stimulation of the sympathetic skin response (SSR) causes habituation. The aim of this study was to determine the effects of electrical stimulus intensity on SSR in 40 healthy controls (mean age+/-SD, 28.0+/-6.7 years). Electrical stimuli at three intensities (5, 15 and 30 mA) were applied to the median nerve at the wrist in four consecutive sessions, after which a magnetic stimulus was applied to the neck. SSR were classified according to the proportion of positive (P) and negative (N) waveform components. Twenty-four subjects had both P and N waveforms. In the first session, 75% of these subjects had a P waveform, indicative of a greater SSR, in response to the 30 mA shock. In the progressive sessions, the SSR waveform was predominately negative (N waveform, session 2, 65%; session 3, 83%; session 4, 75% in response to 30 mA shock), indicating that the SSR was weaker as a result of habituation. There was no clear relationship between stimulus intensity and waveform type, indicating that SSR waveforms are more strongly influenced by habituation than stimulus intensity. However, there was a directly proportional relationship between stimulus intensity and amplitude of the SSR wave (F=70.9, P<0.0001, two-way repeated measure ANOVA), be it positive or negative. The relationship between stimulus intensity and amplitude persisted, even after habituation. Suddenly switching to a magnetic stimulus reverted the SSR wave back to positive (80%), indicating that habituation was rapidly reversible if stimulation of the SSR is altered.

The effects of auditory attention measured from human electrocorticograms

Objective A central question in auditory electrophysiology has been whether selective attention can modulate exogenous components of the scalp-recorded N1 (the ‘N1 effect’). Intracranial electrocorticograms were used in the current work to investigate this issue in greater anatomical detail. Methods Data were recorded from subdural electrodes placed across temporal cortex in 6 patient-volunteers undergoing diagnostic procedures for medically intractable epilepsy. Patients performed a dichotic listening task in which they alternately attended to a series of tones presented to both ears (mean ISI 800 ms) by responding to rare frequency deviants. Results Effects of attention were measured on the largest negative and positive waveform deflections observed between 70 and 220 ms post-stimulus for stimuli presented contralateral to grid location. Peak deflections were most often recorded from the upper bank of the posterior superior temporal gyrus at approximately 89 and 173 ms on average (labeled N90stg and P170stg, respectively). Selective attention had little effect on peak latencies but significantly increased the N90stg for 3 subjects, increased the P170stg for two subjects, and decreased the P170stg for two other subjects. Conclusions Selective auditory attention can modulate neural response in auditory cortex. Significance The effects of attention on the scalp-recorded N1 component may arise in part from the enhancement of exogenous responses in temporal cortex.

P-106: Improvement of Luminance and Luminous Efficiency Using New Negative Sustain Waveform in AC-Plasma Display Panel

A new negative sustain waveform is proposed to improve the sustain and address discharge characteristics of PDP. The effects of conventional positive and proposed negative sustain waveforms on the sustain and address discharge characteristics are examined and compared in the 7-in. test panel with a Ne-Xe (4 %), gas mixture at 100 kHz. In the case of adopting the proposed negative sustain waveform, the luminance and luminous efficiency were improved by about 10 % and 16 %, respectively.

Visual Function with Acupuncture Tested by Visual Evoked Potential

Visual evoked potential (VEP) testing is used frequently and is an important ophthalmologic physiological test to examine visual functions objectively. The VEP is a complicated waveform consisting of negative waveform named N75 and N135, and positive waveform named P100. Delayed P100 latency and greatly attenuated amplitude on VEP are known characteristics for diagnosing optic nerve disease. Acupuncture has been used to treat wide clinical symptoms with minimal side effects. The confirmation of the efficacy of acupuncture generally relies on subjective symptoms. There is not much scientific evidence supporting the acupuncture treatments for eye diseases up to today. However, the VEP test can evaluate objectively and numerically the efficacy of the treatment by the acupuncture. We analyzed 19 healthy subjects (38 eyes). The P100 latencies in the group of less than 101.7 msec (total average) before acupuncture stimulations were not different than those after treatment (98.2 +/- 3.0 msec, 98.2 +/- 4.0 msec, respectively, p = 0.88, n = 17), but the latencies in those subjects with longer or equal to 101.7 msec were statistically different after acupuncture (104.6 +/- 2.8 msec, 101.9 +/- 3.7 msec, respectively, p = 0.006, n = 21). These results show that the acupuncture stimulation contributes to the P100 latencies of pattern reversal (PR)-VEP to some subjects who have delayed latencies, and this electrophysiological method is a valuable technique in monitoring the effectiveness of acupuncture therapy in the improvements of visual functions. The purpose of this study is to evaluate the physiological effects by acupuncture stimulations using PR-VEP in normal subjects.

Negative electroretinograms in pericentral pigmentary retinal degeneration

The clinical presentation and electrophysiological findings are described of three consecutive cases with pericentral pigmentary retinal degeneration. The responses to bright flashes after dark adaptation showed negative waveform shape in all cases. Rod responses were strongly reduced compared with cone responses. Cone electroretinograms elicited by long-duration stimuli showed greater loss of the on-response than the off-response. The ratio of the on-response amplitude to off-response amplitude of these patients (0.52 +/- 0.12; mean +/- SD, n = 6) was significantly smaller than that of normal subject (0.83 +/- 0.21; mean +/- SD, n = 8) (Mann-Whitney U-test, P < 0.01). The electrophysiological findings of these cases suggest a greater defect of inner retinal function, especially in transmission between photoreceptors and depolarizing bipolar cells.

Profound hypotension and associated electrocardiographic changes during prolonged cord occlusion in the near term fetal sheep

To determine whether the onset of fetal hypotension during profound asphyxia is reflected by alterations in the ratio between the T height, measured from the level of the PQ interval, and the QRS amplitude (T/QRS ratio) and ST waveform. Chronically instrumented near-term fetal sheep received complete occlusion of the umbilical cord for either 8 (n=6) or 15-min (n=9). Cord occlusion led to sustained bradycardia and severe acidosis. Mean arterial blood pressure initially rose and then fell to a nadir of 32.6 +/- 2.6 mm Hg in the 8-min group and 9.3 +/- 1.0 mm Hg in the 15-min group (P < .001). The T/QRS ratio rose initially in parallel with mean arterial blood pressure and then reduced as mean arterial blood pressure fell but remained significantly above baseline. Biphasic ST waveforms during occlusion occurred in only 2 fetuses, but biphasic and negative waveforms occurred during reperfusion in the 15-min group, with a significant rise in troponin T levels (0.58 +/- 0.46 versus 0.02 +/- 0.01 ng/mL at 6 h, P < .01). Elevation of the T/QRS ratio does not identify fetal hypotension during severe hypoxia, but abnormal waveforms in the recovery phase may indicate developing cardiac injury.

Clinical manifestations of a unique X‐linked retinal disorder in a large New Zealand family with a novel mutation in CACNA1F, the gene responsible for CSNB2

To describe the phenotype in a New Zealand family with an unusual severe X-linked retinal disorder with a novel I745T mutation in CACNA1F, the gene responsible for incomplete congenital stationary night blindness (CSNB2). Members of the family tree were invited for clinical, psychophysical and electrodiagnostic evaluation. Male family members had severe non-progressive visual impairment, abnormal colour vision, congenital nystagmus, hyperopia and normal fundi. Some were intellectually disabled. Female family members had congenital nystagmus and decreased visual acuity frequently associated with high myopia. Electroretinograms (ERG) identified reduced rod and cone responses with negative waveform in male and female family members, with atypical features for CSNB2. Although there were similarities to CSNB2, distinctive features in male family members included severity of phenotype, and association of intellectual disability. Moreover, all female heterozygotes had clinical and ERG abnormalities. CACNA1F encodes the Ca(v)1.4 alpha1 subunit of a voltage-gated calcium channel, which may mediate neurotransmitter release from photoreceptors. Molecular analyses, reported separately, identified a novel I745T CACNA1F mutation that was associated in vitro with major alterations in gating and kinetics of the Ca(v)1.4 channel. It is speculated that the unique phenotype described in this family may reflect similarly altered function of Ca(v)1.4 channel activity in vivo.

Changes in the sympathetic skin response after thoracoscopic sympathectomy in patients with primary palmar hyperhidrosis

Objective To investigate whether thoracic sympathectomy induced any change in the pattern of abnormalities or in the waveform of the sudomotor skin response (SSR) in patients with primary palmar hyperhidrosis (PPH). Methods We recorded the SSR to median nerve electrical stimuli before and after bilateral thoracoscopic sympathectomy in 27 patients with PPH. We analyzed the changes in amplitude, type of waveform and pattern of abnormality. Results All patients reported symptomatic improvement. The amplitude of the SSR decreased significantly in patients examined within 1 year after surgery, but was not different in patients examined after 1 year. The number of abnormally enhanced responses reduced after surgery, but there was no significant change in the number of patients with enhanced excitability recovery or with double-peak responses to single stimuli. There was a significant increase in the number of SSRs with a predominantly negative waveform after surgery. Conclusions The persistence of SSR abnormalities after surgery suggests that the central nervous system dysfunction is not modified by sympathectomy. The change of the waveform to predominantly negative type after surgery could be the consequence of the decrease in the production of sweating. Significance Our results show the effects of sympathectomy on the SSR and on its abnormal patterns in patients with PPH.

Night blindness and abnormal cone electroretinogram ON responses in patients with mutations in the GRM6 gene encoding mGluR6

We report three unrelated patients with mutations in the GRM6 gene that normally encodes the glutamate receptor mGluR6. This neurotransmitter receptor has been shown previously to be present only in the synapses of the ON bipolar cell dendrites, and it mediates synaptic transmission from rod and cone photoreceptors to this type of second-order neuron. Despite the synaptic defect, best visual acuities were normal or only moderately reduced (20/15 to 20/40). The patients were night blind from an early age, and when maximally dark-adapted, they could perceive lights only with an intensity equal to or slightly dimmer than that normally detected by the cone system (i.e., 2-3 log units above normal). Electroretinograms (ERGs) in response to single brief flashes of light had clearly detectable a-waves, which are derived from photoreceptors, and greatly reduced b-waves, which are derived from the second-order inner retinal neurons. ERGs in response to sawtooth flickering light indicated a markedly reduced ON response and a nearly normal OFF response. There was no subjective delay in the perception of suddenly appearing white vs. black objects on a gray background. These patients exemplify a previously unrecognized, autosomal recessive form of congenital night blindness associated with a negative ERG waveform.

Transmit circuit for imaging with ultrasound

A digital-to-analog converter that outputs positive and negative portions of the desired bi-polar waveform as a representative unipolar waveform (e.g. absolute value of the bi-polar waveform) is connected to a switch. The switch selects between current driver paths as a function of the positive or negative polarity of the desired bi-polar waveform. The current drivers feed a push-pull output amplifier to generate the bi-polar ultrasound waveform. Alternatively, a digital-to-analog converter with differential outputs is connected to two difference amplifiers. The difference amplifiers provide current signals to the push-pull output amplifier through their supply nodes. A single scaling resistor connects between the conventional outputs of two differential amplifiers to reduce mismatching between the positive and negative waveform paths. As a result of the feedback between the two difference amplifiers, a lower level of even harmonic distortion products is achieved.

Cross-Sectional Change of Biological Maturity and Neuromuscular Response Ability in Adolescent Soccer Players

2118 It has been recognized that during adolescence skilled athletes develop a faster neuromuscular response time than non-athletes. Since large individual differences can appear between skeletal maturity and chronological age (CA), the relationship between skeletal maturity and the development of neuromuscular response is unclear. PURPOSE: The purpose of this study was to clarify the relation between development of biological maturity and neuromuscular response ability evaluated from reaction time (RT), premotor time (PMT) and negative waveform latency obtained between 150 to 400 msec later from the reaction stimulus at the electroencephalogram (N200). METHODS: Eighteen male adolescent soccer players (age range: 10.3 to 12.9 years) from the Japanese professional soccer club participated in this study. Biological maturity was evaluated from X-ray of left hand and wrist according to skeletal age (SA) using TWII methods. Visual go/no-go task was employed and subjects were asked to respond to the target stimuli by pushing both hand and foot response switches. PMT of the fiexor pollicis longus and gastrocnemius medialis was also measured. N200 was recorded at the central scalp area based on the international 10–20 methods. RESULTS: The RT as measured from the foot switch shortened from 10 to 12 years of age (536.8 ± 51.7, 501.7 ± 108.1, 448.0 ± 33.3 msec respectively) and it showed a stronger correlation to SA (r = −0.67, p<0.01) as compared to CA (p = −0.49, p<0.05). PMT of the hand and foot correlated more significantly to SA (r = −0.62, p<0.01; r = −0.71, p<0.001) than that of CA (r = −0.59, p<0.05; r = −0.59, p<0.05). It was noteworthy that development of N200 had significant correlation to SA (r = −0.51, p<0.05), however it did not well correlate to CA. CONCLUSIONS: The results of this study indicate the development of neuromuscular response ability such as premotor time and N200 may be influenced by the development of biological maturity (skeletal age) in adolescent soccer players. In conclusion, considering the biological maturity is necessary to investigate the development of neuromuscular response ability in adolescent.

Cross-Sectional Change of Biological Maturity and Neuromuscular Response Ability in Adolescent Soccer Players

2118 It has been recognized that during adolescence skilled athletes develop a faster neuromuscular response time than non-athletes. Since large individual differences can appear between skeletal maturity and chronological age (CA), the relationship between skeletal maturity and the development of neuromuscular response is unclear. PURPOSE: The purpose of this study was to clarify the relation between development of biological maturity and neuromuscular response ability evaluated from reaction time (RT), premotor time (PMT) and negative waveform latency obtained between 150 to 400 msec later from the reaction stimulus at the electroencephalogram (N200). METHODS: Eighteen male adolescent soccer players (age range: 10.3 to 12.9 years) from the Japanese professional soccer club participated in this study. Biological maturity was evaluated from X-ray of left hand and wrist according to skeletal age (SA) using TWII methods. Visual go/no-go task was employed and subjects were asked to respond to the target stimuli by pushing both hand and foot response switches. PMT of the fiexor pollicis longus and gastrocnemius medialis was also measured. N200 was recorded at the central scalp area based on the international 10–20 methods. RESULTS: The RT as measured from the foot switch shortened from 10 to 12 years of age (536.8 ± 51.7, 501.7 ± 108.1, 448.0 ± 33.3 msec respectively) and it showed a stronger correlation to SA (r = −0.67, p<0.01) as compared to CA (p = −0.49, p<0.05). PMT of the hand and foot correlated more significantly to SA (r = −0.62, p<0.01; r = −0.71, p<0.001) than that of CA (r = −0.59, p<0.05; r = −0.59, p<0.05). It was noteworthy that development of N200 had significant correlation to SA (r = −0.51, p<0.05), however it did not well correlate to CA. CONCLUSIONS: The results of this study indicate the development of neuromuscular response ability such as premotor time and N200 may be influenced by the development of biological maturity (skeletal age) in adolescent soccer players. In conclusion, considering the biological maturity is necessary to investigate the development of neuromuscular response ability in adolescent.

Influences of stress waveform and wet environment on fatigue fracture behavior of aramid single fiber

An investigation has been carried out concerning the influences of stress waveform and wet environment on the fatigue fracture behavior of aramid single fiber, Kevlar 49. Tension–tension fatigue tests were conducted under sinusoidal, negative pulse and positive pulse waveforms for the fiber preconditioned in laboratory air and in wet air. The fatigue strength of Kevlar 49 tested in wet air was lower than that in laboratory air, and the fatigue strength in laboratory air under negative pulse waveform was higher than those under other two waveforms. The fibers broke with fiber splitting for the tensile tests and the fatigue tests under sinusoidal and positive pulse waveforms in air. Under negative pulse waveform, however, the fibers whose fatigue lives were longer than 10 5 stress cycles broke with transverse crack. The final fracture morphology under negative pulse waveform corresponded to the transverse undulations observed by an atomic force microscope (AFM).

1017 アラミド単繊維およびアラミド繊維/エポキシ樹脂界面の破壊特性に及ぼす水環境効果

An investigation has been carried out concerning the influence of wet environment on the fatigue fracture behavior of aramid single fiber and on the interfacial properties of aramid/epoxy composite. The aramid fiber used in this investigation was Kevlar 49 manufactured by Du Pont. Tension-tension fatigue tests of a single fiber were conducted under sinusoidal, negative pulse and positive pulse waveforms for the fiber preconditioned in laboratory air and in wet air (RH 98±2%, 20±2℃). The fatigue strength of Kevlar49 tested in wet air was lower than that in laboratory air, and the fatigue strength in air under negative pulse waveform was higher than those under other two waveforms. The fiber/matrix interfacial strength was severely decreased between 4 and 7 week immersion time in deionized water at 80℃, and thereafter showed the plateau. This change with immersion time did not correspond with that of the water gain of the pull-out specimens, because the water gain did not reflect the one in the fiber/matrix interface.

Event-related potential measures of the inhibition of information processing: I. Selective attention in the waking state

This article reviews the effects of selective attention on event-related potentials (ERPs). Attention has little, if any, effect on short-latency exogenous ERPs. The longer-latency ERPs can be markedly affected by manipulation of the subject's level of attention. For example, a late positive wave, P300, appears to occur only if subjects actively detect an infrequently occurring target stimulus. However, a number of other late positive waves may also occur independently of the direction of attention, particularly if elicited by highly biologically or psychologically relevant stimuli. Attention may also interact with an earlier, apparently exogenous, negative waveform, N1. This could be due to the overlapping and summating effect of an attentional-related waveform, the processing negativity. The presentation of a physically deviant stimulus occurring among a train of homogeneous standard stimuli will elicit another negative wave, the mismatch negativity (MMN). The MMN has traditionally been thought to occur independently of attention. More recent studies have, however, shown that attention can modulate the MMN. This may, however, be explained by the summating effects of other overlapping components. Interpreting the scalp-recorded ERP can therefore require judicious care. Design of experiments must take into account the fact that the magnitude of attentional effects will depend on a number of different influences, some of which are very subtle and complex. A problem with any study in the waking and alert human is that the subject may not be able to completely ignore stimuli, in spite of instructions to do so. For this reason, the study of unconscious states, such as sleep, may prove to be especially fruitful in understanding the effects of attention in the waking state.

Effects of stress waveform and water absorption on the fatigue strength of angle-ply aramid fiber/epoxy composites

The influences of stress waveform and water absorption on the tension–tension fatigue fracture behavior were investigated in ±45° angle-ply laminates of aramid fiber reinforced epoxy matrix composite. For dry specimens, the fatigue strength under negative pulse waveform was higher than that under the positive pulse waveform. Rotation of fibers to the longitudinal direction, which resulted from creep deformation caused by the cyclic loading superimposed on the maximum stress hold time, decreased the compliance, thereby increasing the fatigue life under the negative pulse waveform. Water absorption degraded the fiber/matrix interfacial strength and caused the swelling of the matrix, which resulted in decreases in the static tensile strength and fatigue strength. Although the strength under the negative pulse waveform was slightly higher than that under the positive one, the influence of stress waveform on fatigue strength was smaller in wet specimens.

Psychophysical estimates of cochlear phase response: masking by harmonic complexes.

Harmonic complexes with identical component frequencies and amplitudes but different phase spectra may be differentially effective as maskers. Such harmonic waveforms, constructed with positive or negative Schroeder phases, have similar envelopes and identical long-term power spectra, but the positive Schroeder-phase waveform is typically a less effective masker than the negative Schroeder-phase waveform. These masking differences have been attributed to an interaction between the masker phase spectrum and the phase characteristic of the basilar membrane. To explore this relationship, the gradient of stimulus phase change across masker bandwidth was varied by systematically altering the Schroeder-phase algorithm. Observers detected a signal tone added in-phase to a single component of a masker whose frequencies ranged from 200 to 5000 Hz, with a fundamental frequency of 100 Hz. For signal frequencies of 1000-4000 Hz, differences in masking across the harmonic complexes could be as large as 5-10 dB for phase gradients changing by only 10%. The phase gradient that resulted in a minimum amount of masking varied with signal frequency, with low frequencies masked least effectively by stimuli with rapidly changing component phases and high frequencies masked by stimuli with more shallow phase gradients. A gammachirp filter was implemented to model these results, predicting the qualitative changes in curvature of the phase-byfrequency function estimated from the empirical data: In some cases, small modifications to the gammachirp filter produced better quantitative predictions of curvature changes across frequency, but this filter, as implemented here, was unable to accurately represent all the data.

ST waveform changes during repeated umbilical cord occlusions in near-term fetal sheep

Objective: This study was undertaken to determine whether changes in the fetal ST waveform during repeated umbilical occlusion reflect the development of hypotension and acidosis. Study Design: Chronically instrumented, near-term fetal sheep received 1-minute total umbilical cord occlusion either every 5 minutes for 4 hours (1:5 group, n = 8), or every 2.5 minutes until blood pressure fell <20 mm Hg on 2 successive occlusions (1:2.5 group, n = 8). Results: Umbilical cord occlusion caused variable decelerations, with sustained hypertension in the 1:5 group and little change in acid-base status (pH = 7.34 ± 0.07 after 4 hours). In contrast, the 1:2.5 group showed progressive hypotension and metabolic acidemia (pH 6.92 ± 0.1 after the final occlusion). There was a marked increase in ST waveform height during occlusions; this increase was greater in the 1:2.5 group (P <.001), but there was overlap between the groups. ST waveform height between occlusions was significantly higher in the 1:2.5 group (P <.001) until negative and biphasic ST waveforms developed in these fetuses between occlusions in the final 30 minutes. Conclusion: ST waveform elevation occurs during umbilical cord occlusions but only crudely reflects the severity of hypoxia. Interocclusion waveform height may be a better reflection of the severity of hypoxia. The appearance of biphasic and negative waveforms between occlusions may be a useful marker for severe decompensation. (Am J Obstet Gynecol 2001;184:743-51.)