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Results 451 - 500 of 937
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An J Y - - 2000
Biological desulfurization using C. thiosulfatophilum has many more advantages over conventional physico-chemical methods due to low operational cost and no production of secondary pollutants. However, it requires effective and economical supply of light energy, which is a key factor in determining the success of commercialization. In this study, optical-fiber photobioreactor ...
Quintas M L - - 2000
In order to evaluate age related changes of the elastic fiber system in the interfoveolar ligament, we studied the deep inguinal ring from 33 male cadavers aged from stillborn to 76 years. Selective and alternated staining methods for elastic fibers were performed to differentiate oxytalan, elaunin, and mature elastic fibers. ...
Slugg R M - - 2000
The goal of this study was to determine the capacity of primary afferent nociceptive fibers (nociceptors) to encode information about noxious mechanical stimuli in primates. Teased-fiber techniques were used to record from 14 A-fiber nociceptors and 18 C-fiber nociceptors that innervated the hairy skin. Stimulus-response functions were examined with an ...
Yates G K - - 2000
Rate-versus-intensity functions recorded from mammalian auditory-nerve fibers have been shown to form a continuum of shapes, ranging from saturating to straight and correlating well with spontaneous rate and sensitivity. These variations are believed to be a consequence of the interaction between the sensitivity of the hair-cell afferent synapse and the ...
Dianov E M - - 2000
We have theoretically investigated, for what is to our knowledge the first time, the electrostrictive response in a single-mode ring-core fiber. We found that the electrostrictive response function differs strongly from those of standard fibers with a Gaussian light-intensity profile.
Correa-Lacárcel J - - 2000
We have characterised the c-fos expression patterns in various centers of the visual pathway of adult rats monocularly stimulated either by continuous or flickering light at different frequencies. Results show different immunocytochemical patterns in all centers studied, the geniculate lateral complex (LGC), superior colliculus (SC) and primary visual cortex (Oc1), ...
Mendelson N H - - 2000
Supercoiling motions that accompany the growth of bacterial macrofibers (multicellular filamentous structures formed in B. subtilis by cell division without separation) are responsible for rolling, pivoting, and walking of fibers on a surface. Fibers possess a fulcrum about which they pivot and step in a chiral manner; forces and torques ...
Uchida F - - 2000
A 21-year-old woman had paroxysmal wide QRS tachycardia with a left bundle branch block configuration and a retrograde conducted P wave just behind the QRS complex. An electrophysiological study revealed antidromic atrioventricular tachycardia involving an atrioventricular connection with decremental conduction as the anterograde limb and normal atrioventricular node as the ...
Cui Y - - 2000
Single chicken erythrocyte chromatin fibers were stretched and released at room temperature with force-measuring laser tweezers. In low ionic strength, the stretch-release curves reveal a process of continuous deformation with little or no internucleosomal attraction. A persistence length of 30 nm and a stretch modulus of approximately 5 pN is ...
Letelier J C - - 2000
The optic tectum of the pigeon is a highly organized, multilayered structure that receives a massive polystratified afference of at least five different populations of retinal ganglion cells and gives rise to various anatomically segregated efferent systems. The synaptic organization of retino-tectal circuitry is, at present, mostly unknown. To investigate ...
Silver F H - - 2000
Fibrous collagen networks are the major elements that provide mechanical integrity to tissues; they are composed of fiber forming collagens in combination with proteoglycans (PGs). Using uniaxial tensile tests we have studied the viscoelastic mechanical properties of rat tail tendon (RTT) fibers and self-assembled collagen fibers that were stored at ...
Ishay J S - - 2000
Examinations carried out via atomic force microscope (AFM) on the Oriental hornet Vespa orientalis (Hymenoptera, Vespinae) revealed, on the cuticle of the gaster in the region of the yellow stripes, flats bearing a grid in the form of parallel strips. Such configurations, of the same dimensions, were obtained also by ...
Andrew D - - 1999
Tissue injuries commonly cause an increase in pain sensitivity, so that normally painful stimuli become more painful (hyperalgesia), and those usually associated with nonnoxious sensations evoke pain (allodynia). The neural bases for these sensory phenomena have been explored most extensively using heat injuries and experimental arthritis as models. Heat sensitization ...
Andrew D - - 1999
These experiments investigated temporal summation mechanisms of tonic cutaneous mechanical pain. Human volunteers provided psychophysical estimates of pain intensity, which were compared with discharge patterns of rat cutaneous nociceptors tested with identical stimulus protocols. Human subjects made either intermittent or continuous ratings of pain intensity during stimulation of the skin ...
Köppl C - - 1999
Rate-intensity functions, i.e., the relation between discharge rate and sound pressure level, were recorded from single auditory nerve fibers in the barn owl. Differences in sound pressure level between the owl's two ears are known to be an important cue in sound localization. One objective was therefore to quantify the ...
Dumitru D - - 1999
OBJECTIVE: Motor unit action potential (MUAP) recordings are modeled by means of a single muscle fiber simulation program, to define two key subcomponents comprising the complete physiologic MUAP duration. A number of defining properties of these subcomponents are further developed. METHODS: A single muscle fiber simulation program is utilized with ...
Zhelyaskov V R - - 1999
We report a new method of generating nitric oxide (NO) that possesses several advantages for experimental use. This method consists of a photolysis chamber where NO is released by illuminating photolabile NO donors with light from a xenon lamp, in conjunction with feedback control. Control of the photolysis light was ...
Yong J C - - 1999
We demonstrate a novel frequency-domain-multiplexing technique for implementing polarimetric fiber laser current sensors. Each sensor operates at a different polarization-mode beat frequency that is modulated in response to applied electric current. A bank of bandpass filters can be used to separate signals from different sensors. A simple frequency-demodulation technique based ...
Magerl W - - 1999
Feedback-controlled laser heat was used to stimulate the hairy skin of the hand dorsum and forearm, and heat-evoked cerebral potentials were recorded at midline (Fz, Cz, Pz) and temporal (T3, T4) scalp positions. Based on data from primary afferent electrophysiology a stimulus level (40 degrees C) was chosen, which is ...
Zalewska E - - 1999
Motor unit action potential (MUAP) may be characterized by two complementary features: global and detailed. The global feature is represented by the envelope of the curve while the detailed feature describes the fluctuations around the envelope. The global feature represents the magnitude of the signal and is related to the ...
Sacks M S - - 1999
Porcine small intestinal submucosa (SIS) has been shown to serve as a remodelable tissue scaffold in a wide range of applications. Despite the large number of experimental studies, there is a lack of fundamental information on SIS anisotropic mechanical behavior and how this behavior changes postimplantation. As a first step ...
Ferretti M - - 1999
The shape, size and density of osteocyte lacunae in parallel-fibered and lamellar bone were histomorphometrically analyzed in relation to the organization of the collagen fiber texture and the animal species (frog, sheep, dog, bovine, horse and man). The following parameters were measured under the light microscope (LM) by a computer-assisted ...
Bartkowiak A - - 1999
A new generation of microcapsules based on the use of oligomers which participate in polyelectrolyte complexation reactions has been developed. These freeze-thaw stable capsules have been applied as a bioartificial pancreas and have resulted in normoglycemia for periods of six months in concordant xenotransplantations. The new chemistry permits the control ...
Dickinson T A - - 1999
We report a new approach to designing an artificial nose based on high-density optical arrays that directly incorporate a number of structural and operational features of the olfactory system. The arrays are comprised of thousands of microsphere (bead) sensors, each belonging to a discrete class, randomly dispersed across the face ...
Locke R - - 1999
The synaptic activity transmitted from vestibular hair cells of the lagena to primary afferent neurons was recorded in vitro using sharp, intracellular microelectrodes. At rest, the activity was composed of miniature excitatory postsynaptic potentials (mEPSPs) at frequencies from 5 to 20/s and action potentials (APs) at frequencies betwen 0 and ...
Chen X - - 1999
While it is generally assumed that nociceptor sensitization underlies peripheral hyperalgesia, there is disagreement regarding the ability of inflammatory mediators to sensitize nociceptors to mechanical stimuli. In this in vivo electrophysiological study, mechanical threshold and response to sustained threshold and sustained suprathreshold mechanical stimuli were measured before and after intradermal ...
Chan S O - - 1999
The changes in quadrant-specific fiber order in the retinofugal pathway of the C57-pigmented mouse aged embryonic day 15 were investigated by using single- (1,1'-dioctadecyl-3,3,3',3'-tetramethyl-indocarbocyanine perchlorate; DiI) and double- (N-4-4-didecylaminostyryl-N-methylpyridinium iodide; 4Di-10ASP in addition to DiI) labeling techniques. At this earliest stage of development, before any fibers arrive at their targets, ...
Carney L H - - 1999
Previous reports of frequency modulations, or glides, in the impulse responses of the auditory periphery have been limited to analyses of basilar-membrane measurements and responses of auditory-nerve (AN) fibers with best frequencies (BFs) greater than 1.7 kHz. These glides increased in frequency as a function of time. In this study, ...
Oberson P - - 1999
We present the principle of optical frequency modulation via the Doppler effect obtained by rapidly stretching an optical fiber and thus modifying the optical path of the light propagating in the fiber. This procedure creates a pure frequency shift, with no degradation of the spectrum. Moreover, the effect is wavelength ...
Miller C A - - 1999
We recorded action potentials from single auditory-nerve fibers of cats using monophasic current pulses delivered by a monopolar intracochlear electrode. These simple stimuli provided a means of investigating basic properties and hypotheses of electrical excitation. Standard micropipette recording techniques were used. Responses to anodic (positive) and cathodic (negative) stimulus pulses ...
Widiyatmoko B - - 1999
To expand the span of the optical frequency comb (OFC), we generated the second harmonics of an OFC at 1.55microm , using a multiperiod periodically poled lithium niobate (PPLN) crystal. A coupled-cavity OFC generator with an average output power of 0.2 mW was amplified and expanded with a fiber amplifier ...
Barrett M D - - 1999
We have developed an extrinsic Fabry-Perot interferometer (EFPI) to measure displacements of microscopic, living organelles in the inner ear. The EFPI is an optical phase-shifted instrument that can be used to measure nanometer displacements. The instrument transmits a coherent light signal to the end of a single glass optical fiber ...
Sutter E E - - 1999
The local responses of the multifocal ERG reveal continuous changes in the second order waveforms from the nasal to the temporal retina. Scrutiny of these changes suggests the presence of an additive component whose latency increases with the distance of the stimulus from the optic nerve head. This observation led ...
Hanna W M - - 1999
Granuloma annulare (GA) is a condition characterized by the presence of palisading granulomas usually in the dermis. Traditionally, the histopathological changes are described as consisting of focal degeneration of dermal collagen fibers. However, no convincing evidence for such alteration is found in the literature. A histopathological study was done to ...
Street A M - - 1999
The conditions for activation transmission across a region of extracellular space was demonstrated in two-dimensional preparations with results consistent with those previously seen in the one-dimensional fiber studies. In addition, one sees changes in action potential morphology which occur in the tissue nearest the connective-tissue border as well as changes ...
Miller R L - - 1999
This paper attempts to connect deficits seen in the neural representation of speech with perceptual deficits. Responses of auditory-nerve fibers were studied in cats exposed to acoustic trauma. Four synthetic steady-state vowels were used as test signals; these stimuli are identical, except that the second format (F2) resonator in the ...
Osaki S - - 1999
It is important to obtain information about the collagen fiber orientation in biological fibrous tissues such as human and animal skins because the collagen fiber orientation in the skins may closely relate to the motional functions of the body. However, no reports are yet available on the distribution of collagen ...
Narayan S S SS The Hugh Knowles Center, Audiology and Hearing Sciences Program, Department of Communication Sciences and Disorders, and Institute for Neuroscience, Northwestern University, Evanston, IL 60208-3550, - - 1998
Responses to tones of a basilar membrane site and of auditory nerve fibers innervating neighboring inner hair cells were recorded in the same cochleae in chinchillas. At near-threshold stimulus levels, the frequency tuning of auditory nerve fibers closely paralleled that of basilar membrane displacement modified by high-pass filtering, indicating that ...
Kuo R L - - 1998
We compared the impact of various energy settings, frequency, and fiber diameters on the stone fragmentation capabilities of the holmium laser. Stone phantoms, made from plaster of Paris and uniform in weight, were treated with one of two laser fiber sizes: small (200 and 365 microm) and large (550 and ...
Raymond J L - - 1998
Mechanisms for the induction of motor learning in the vestibulo-ocular reflex (VOR) were evaluated by recording the patterns of neural activity elicited in the cerebellum by a range of stimuli that induce learning. Patterns of climbing-fiber, vestibular, and Purkinje cell simple-spike signals were examined during sinusoidal head movement paired with ...
Takemasa T - - 1998
The stress fiber (bundles of actin filaments) is one of the most prominent cytoskeletal components that contributes to the maintenance of cell architecture. It has generally been believed that upon cyclic stretching, both cells and their stress fibers become perpendicularly aligned to the direction of stretching. However, using our newly ...
Kirsch K M - - 1998
BACKGROUND: Clinical improvement in photodamaged skin after carbon dioxide (CO2) laser resurfacing is thought to result in part from thermal collagen shrinkage. The presence of such collagen has not been unequivocally demonstrated. To identify and characterize the morphological features of collagen after CO2 laser exposure, we irradiated ex vivo human ...
Ohlemiller K K - - 1998
During an investigation of the effects of cochlear cooling on frequency tuning and input/output relations of single auditory nerve fibers in gerbil (Ohlemiller and Siegel (1994) Hear. Res. 80, 174-190), cooling-related changes in post-stimulus time histogram (PSTH) shape and phase-locking to tonebursts were characterized in a small sample of neurons. ...
Treede R D - - 1998
To compare the heat responses of mechanically sensitive and mechanically insensitive A-fiber nociceptors, an electrical search technique was used to locate the receptive fields of 156 A-fibers that innervated the hairy skin in the anesthetized monkey (77 A beta-fibers, 79 A delta-fibers). Two-thirds of these afferents were either low-threshold mechanoreceptors ...
Markolf K L - - 1998
The arthroscopically implantable force probe transducer, which measures the effects of local ligament fiber tension, was inserted into the anteromedial band of the anterior cruciate ligament after measurements with the differential variable reluctance transducer were completed in Part I of this study. The overall goals in Part II remained the ...
Sato S - - 1998
PURPOSE: Elastic fibers in the attachment regions of the temporomandibular joint (TMJ) are considered important in the movements of the disc during jaw motion. This study was designed to determine whether there are change in the elastic fibers of the TMJ when the disc is perforated for a long period. ...
Walsh E J - - 1998
The olivocochlear bundle (OCB) was cut in neonatal cats to evaluate its role in the development of normal cochlear function. Approximately 1 year after deefferentation, acute auditory nerve fiber (ANF) recordings were made from lesioned animals, lesion shams, and normal controls. The degree of deefferentation was quantified via light microscopic ...
Butler D J - - 1998
The amount of light occluded by a fiber as it passes through alaser beam can be used as the basis for fiber-diametermeasurement. This technique is analyzed with a two-dimensionalrigorous model. The occlusion seen for dielectric fibers as afunction of their diameter is highly oscillatory owing to interferencebetween the light transmitted ...
Christensen-Dalsgaard J - - 1998
Responses to free-field sound of 401 fibers from the VIIIth nerve of the grassfrog, Rana temporaria, are described. The spontaneous activities of the fibers ranged from 0 to 75 spikes/s, showing only weak correlation with frequency or sensitivity of the fibers. The highest spontaneous activities were approximately twice as high ...
Hensman C - - 1998
BACKGROUND: Skin burns and ignition of drapes have been reported with the use of cold light sources. The aim of the study was to document the temperature generated by cold light sources and to correlate this with the total radiated power and infrared output. METHODS: The temperature, total radiated power, ...
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