Assessing the state of biologically inspired design from three perspectives: academic, public, and practitioners.

Biologically inspired design (BID) applies natural solutions to engineering challenges. Due to the widespread success of BID, we examine the following research question: how does the purpose of applying, the inspiration source, and the application of BID differ between academics, the public, and practitioners? Answering this question can help us design the tools used to support BID, provide an understanding of the current 'state of BID' and identify where BID solutions have not been widely utilized. Identifying gaps in utilization could prompt investigations into BID methods in new fields. To answer this research question, 660 BID samples were gathered equally from three data sources: Google Scholar, Google News, and the Asknature.org 'Innovations' database. The data were classified across seven dimensions and 68 subcategories. The conclusions of our research deliver insights into three areas. First, we identify trends in BID independent of source. For example, 72.5% of the biomimicry samples had the purpose of improving functionality and 87.6% of the samples impacted the usage phase of a product's life cycle. Secondly, by examining the distribution of BID within each source, we identify areas for potential outreach or application. Finally, by contrasting BID results between three sources (academic, news, and practical case studies) we gain an understanding of the disparities between the three. This analysis provides BID researchers and practitioners with a useful insight into the present state of this field, with the goal of motivating future research and application.

The effects of phytase on growth performance and intestinal transit time of broilers fed nutritionally adequate diets and diets deficient in calcium and phosphorus.

Five experiments (Exp.) were conducted to determine the effects of phytase on growth performance and intestinal transit time in chicks fed nutritionally adequate diets and diets deficient in Ca and nonphytate P (nPP). In Exp. 1 and 2, chicks were fed a nutritionally adequate diet from 0 to 6 d or from 0 to 4 d posthatching; assay periods were 8 or 10 d; average initial BW were 98 or 79 g; and average final BW were 371 or 369 g, respectively. Treatments were replicated with 12 pens of 5 chicks each. Corn-soybean meal (C-SBM) diets were adequate in all nutrients except Ca and nPP where appropriate. The treatments were 1) C-SBM, 1.0% Ca, and 0.45% nPP; 2) C-SBM, 0.80% Ca, and 0.25% nPP; 3) Diet 1 + 600 phytase units/kg of diet; 4) Diet 2 + 600 phytase units/kg of diet. Experiments 3, 4, and 5 were conducted to determine the effects of phytase on intestinal transit time in broilers. Broilers were fed the same nutritionally adequate diet from 0 to 18, 27, or 23 d posthatching, and the assay periods were 7 d. Treatments were replicated with 18 individually penned broilers. Average initial BW were 768, 1,108, or 838 g, and average final BW were 1,299, 1,704, or 1,392 g in Exp. 3 to 5, respectively. Transit time data were collected on d 1 and 7 of the Exp. Diets were 1) C-SBM, 0.9% Ca, and 0.35% nPP; 2) C-SBM, 0.80% Ca, and 0.25% nPP + 600 phytase units/kg of diet. Transit time was calculated as the difference between the time feed was first ingested and the time of first appearance of solid feces. In Exp. 1 and 2, the reduction in dietary Ca and nPP reduced (P < 0.01) average daily gain (ADG), average daily feed intake (ADFI), and gain:feed. Phytase addition increased (P < 0.02) ADG and ADFI in diets deficient in Ca and nPP and in the nutritionally adequate diets. In Exp. 2, the reduction in Ca and nPP reduced (P < 0.01) toe and tibia ash percentage, but phytase addition increased (P < 0.01) toe and tibia ash percentage. The increase in toe ash percentage was greater in chicks fed the Ca and nPP deficient diet than in chicks fed the nutritionally adequate diet (Ca and nPP x phytase, P < 0.01). In Exp. 3, 4, and 5, transit time on d 1 was faster (P < 0.03) in chicks fed phytase. On d 7, transit time tended to be faster in chicks fed phytase, but the effect was not significant (P = 0.15). These data indicate that phytase increases ADG and ADFI in diets deficient in Ca and nPP and in diets formulated to be adequate (or excess) in all nutrients for broiler chicks. The increase in ADG and ADFI in chicks fed the nutritionally adequate diet may be due to a faster transit time of feed through the digestive tract, resulting in a greater feed intake and gain.

The interactive effects of Eimeria acervulina infection and phytase for broiler chicks.

An experiment was conducted to determine the interactive effects of Eimeria acervulina infection and phytase in male broiler chicks. Chicks were standardized from 0 to 4 d posthatching, and the assay period was 5 to 15 d. Treatments were replicated with 6 pens of 5 chicks each. The initial and final BW were 67 and 363 g. A corn-soybean meal diet formulated to provide 1.26% total Lys and 3,200 kcal of ME/kg was used, and it was adequate in all other nutrients except Ca and nonphytate P (NPP) when appropriate. The treatments were in a 2 x 2 x 2 factorial arrangement: adequate Ca and NPP (1.0% Ca and 0.45% NPP) or inadequate Ca and NPP (0.80% Ca and 0.25% NPP), 0 or 600 phytase units/kg of diet, and uninfected or infected with 400,000 E. acervulina oocysts on d 0, 3, and 6 of the experiment. Daily gain, average daily feed intake, and gain:feed (GF) were reduced (P < 0.01) by the coccidial infection and the reduction in Ca and NPP. Phytase addition increased (P < 0.02) average daily gain and average daily feed intake, regardless of the Ca and NPP contents of the diet or the presence of coccidiosis. The GF was increased by phytase but only in uninfected chicks (phytase x coccidiosis, P < 0.02). Toe and tibia ash percentages were decreased (P < 0.01) in chicks fed diets deficient in Ca and NPP, but tibia ash was decreased more by Ca and NPP in healthy chicks than in infected chicks (coccidiosis x Ca and NPP, P < 0.02). Phytase increased (P < 0.02) toe and tibia ash but only in diets deficient in Ca and NPP (phytase x Ca and NPP, P < 0.01). Phytase increased toe ash percentage of healthy chicks fed diets deficient in Ca and NPP, but it had less of an effect in infected chicks fed diets deficient in Ca and NPP (coccidiosis x Ca and NPP x phytase, P < 0.08). Also, phytase was less effective in increasing tibia ash percentage in coccidiosis-infected chicks than in uninfected chicks (phytase x coccidiosis, P < 0.02). These data indicate that phytase is effective in the presence of a coccidial infection, but based on GF and tibia ash percentage, it may not be as effective as in uninfected chicks. Also, phytase increased average daily gain and average daily feed intake in uninfected chicks fed diets formulated to be adequate (or in excess) in all nutrients for male broiler chicks.

Magnetic spin ladder (C5H12N)2CuBr4: high-field magnetization and scaling near quantum criticality.

The magnetization, M(H< or =30 T,0.7< or =T< or =300 K), of (C5H12N)2CuBr4 has been used to identify this system as an S = 1/2 Heisenberg two-leg ladder in the strong-coupling limit, J( perpendicular) = 13.3 K and J( parallel) = 3.8 K, with H(c1) = 6.6 T and H(c2) = 14.6 T. An inflection point in M(H,T = 0.7 K) at half saturation, M(s)/2, is described by an effective XXZ chain. The data exhibit universal scaling behavior in the vicinity of H(c1) and H(c2), indicating that the system is near a quantum critical point.

Fundamental frequency during phonetically governed devoicing in normal young and aged speakers.

Age-related changes in the laryngeal system can be perceived as altered vocal pitch and increased pitch variability. However, reports vary as to the nature and extent of an age effect on fundamental frequency (F0) for analyses taken over long segments of connected speech. Analysis of F0 across a smaller time frame may be more informative. Young speakers show an increase in F0 associated with phonetically governed devoicing gestures that is likely mediated by increased vocal fold stiffness. Anatomic and neurophysiologic changes in the aged larynx may limit the role of increased vocal fold stiffness in the devoicing gesture. This study tests the hypothesis that aged speakers show a smaller increase in F0 in association with the devoicing gesture for production of an intervocalic voiceless obstruent than do young speakers. Normal young and aged speakers produced a short sentence containing an intervocalic voiceless obstruent. Measures of F0 were obtained for ten cycles before voice offset and ten cycles after voice onset. Young speakers showed a small increase in F0 during devoicing whereas aged speakers showed a decrease in F0 during devoicing. Aged speakers seem to rely more on vocal fold abduction rather than a combination of abduction and tensing to achieve devoicing.

Task complexity effect on vocal reaction time in aged speakers.

The aged population is at risk for impaired speech communication due to the increased likelihood of deterioration of central nervous system (CNS) processes that underlie cognition, language, and/or speech motor control. Vocal reaction time (RT) may provide a means of quantifying the efficiency of CNS processes that underlie speech production. The present study used a simple RT paradigm to investigate effects of the complexity of the required task on vocal RT in normal young and aged speakers. Task complexity was represented by two levels: a single word and a short sentence. Only the aged subjects showed a significant task complexity effect on vocal RT. Furthermore, the between-group RT difference increased as a function of task complexity. Specific causes for the increase in vocal RT for the aged subjects are presently unknown, but likely reside in altered respiratory biomechanics and reduced efficiency of CNS motor processing.

Time-frequency analyses of thyroarytenoid myoelectric activity in normal and spasmodic dysphonia subjects.

Digital recordings of thyroarytenoid (TA) myoelectric activity (via percutaneous hooked-wire electrodes) were obtained for 10 normal control subjects and 10 subjects with spasmodic dysphonia during performance of five tasks of varying complexity: quiet breathing, Valsalva maneuver, whispered /i/, voiced /i/, and "beep beep went the heap." Time-frequency power spectral density functions, PSD(f,t), were determined for a selected segment of the signals, and measures of median frequency, mean frequency, bandwidth, and center frequency of PSD(f,t) were derived for each sample point. Statistical median, mean, standard deviation, minimum, maximum, and mode of the power spectral density measures were computed to compose feature vectors for each TA myoelectric recording. Statistical pattern recognition procedures using maximum likelihood classification tests were applied to the feature space to discriminate disordered from normal speakers for each task. Findings indicate a high level of discriminability between subject groups for phonated speaking tasks in contrast to low levels of discriminability for whispered and nonspeech tasks. Graphical presentations of three-dimensional PSD(f,t) plots are given that illustrate changes in spectral characteristics of TA EMG at the onset of laryngospasm.

Statistical analyses of electromyographic activity in spasmodic dysphonic and normal control subjects.

Heterogeneity in the quality and task sensitivity of vocal symptoms in the spasmodic dysphonia (SD) population contributes to controversy as to whether this is a single disorder or two disorders with different etiologies (neurogenic versus psychogenic). Perceptual and acoustic assessments of vocal symptoms are inadequate to resolve this controversy. However, myoelectric events are intimately proximal to the source of vocal disruption and may be informative. The present report employs statistical modeling of quantitative amplitude measures of electromyographic activity recorded from thyroarytenoid to examine neuromotor bases of vocal symptoms in SD. Consideration of perceptual ratings of the quality and task sensitivity of vocal symptoms in the context of statistical models provides support for the conclusion that the range of vocal symptoms identified as SD represents a single, neurogenic disorder.

Linguistic performance and regional cerebral blood flow in persons who stutter.

In a series of studies regarding CNS dysfunction in stuttering, we have examined linguistic and motoric performance in the context of measures of brain function. Previous studies of adults with developmental stuttering identified alterations in brain function (metabolic and electrophysiologic) in cortical regions implicated in models of speech motor control and language processing. We also identified a sub-group of these subjects who exhibited linguistic performance deficits related to speech performance deficits. The present study examined the hypothesis that adults who stutter and who show linguistic performance deficits will also show metabolic alterations in cortical regions classically related to language processing, whereas adults who stutter but who do not show linguistic performance deficits will not show these cortical metabolic alterations. Significant relative blood flow asymmetry (left < right) was observed in middle temporal and inferior frontal cortical regions only for adults who both stuttered and showed linguistic performance deficits. Results support models that explicitly recognize that efficient integration of linguistic, motoric, and cognitive processes is critical to the production of oral/verbal fluency and to understanding sources of fluency failure.

Foreperiod duration, range, and ordering effects on acoustic LRT in normal speakers.

One quantitative measure of vocal motor control is phonation onset latency relative to presentation of an external stimulus in a reaction time task. However, variables within the design of reaction time experiments can affect laryngeal reaction time (LRT) values. The present study examines effects of foreperiod characteristics on LRT for normal speakers. Foreperiod is the interval between presentation of warning and response cues. LRT was affected by absolute foreperiod duration, by the average foreperiod duration of a block of trials, and by the ordering and range of foreperiods within a block of trials. Results are discussed with respect to foreperiod effects on the subjective expectancy and objective probability of occurrence of the response cue and on the timing of neurophysiologic processes. Control of subjective effects is critical to assessment of neurophysiologic constraints on LRT.

The relationship between communication attitude, anxiety, and depression in stutterers and nonstutterers.

People who stutter are frequently viewed as more anxious than nonstutterers and as being depressed. Further, a strong and pervasive stereotype is held by nonstutterers that people who stutter are guarded, nervous, and tense. This study examined self-perceptions of general state and trait anxiety, depression, and communication attitude in matched groups of stutterers and nonstutterers. Results refute the assertion that people who stutter are more anxious or depressed than those who do not. Anxiety and depression are not related to self-ratings of stuttering severity. Communication attitude is negative for this group of people who stutter and becomes increasingly negative as self-ratings of stuttering become more severe. People who stutter, grouped by severity rating, differed in the strength of the relation between measures of communication attitude, anxiety, and depression. Findings suggest that the anxiety of people who stutter is restricted to their attitude towards communication situations and that it is a rational response to negative communication experiences.

Brain blood flow related to acoustic laryngeal reaction time in adult developmental stutterers.

The 1980s witnessed renewed interest in the relation between developmental stuttering and central nervous system (CNS) abnormalities. We have reported differences between nonstutterers and developmental stutterers on electrophysiologic (QTE) and metabolic (rCBF) measures of brain function. A critical step in the interpretation of results of functional brain imaging studies is to determine the relation, if any, of identified CNS abnormalities to speech motor control in persons who stutter. In this study we addressed the interpretation of rCBF findings by asking whether we could identify patterns of impaired acoustic laryngeal reaction time (LRT) as a function of response complexity parallel to rCBF findings. Stutterer subgroups determined by clinical severity ratings were not differentiated by LRT values as a function of response complexity. Stutterers with relative blood flow asymmetry below the normal median value involving both left superior and middle temporal regions of interest (ROIs) showed significantly longer LRT for the complex response than did normal speakers and stutterers with above-normal median relative flow values to at least one of these temporal ROIs. Stutterer subgroups based on reduced cingulate flow alone were not differentiated by LRT values. Findings are consistent with Goldberg's (1985) model of CNS premotor processing. Findings also suggest that stutterer subgroups might be distinguished by the presence, loci, and relative magnitude of cortical and/or subcortical rCBF abnormality in regions that subserve a fluency-generating system.

Multichannel electromyographic observations in spasmodic dysphonia patients and normal control subjects.

Spasmodic dysphonia is primarily a disorder of vocalization. Increasing evidence, however, suggests that individuals with this disorder comprise a heterogeneous population characterized by abnormal motor control throughout the vocal tract. Multichannel simultaneous electromyography was performed on 11 spasmodic dysphonia patients and 10 normal awake subjects to investigate both the distribution of neuromotor abnormality within the vocal tract (eg, intrinsic and extrinsic laryngeal muscles, tongue, and palate) and the contribution of activation of higher central nervous system centers to observed abnormality. Experimental tasks ranged from vegetative (quiet breathing) to simple linguistic (short sentences). Digitized electromyographic signals were analyzed to compute the amplitude envelope and extract a set of parameters that represent amplitude characteristics. Electrode insertions were cross-validated by quantitative analysis of patterns of activation across selected reference tasks and by traditional qualitative methods. Between-group differences were found for measures of normalized median and peak token amplitudes. These differences are both task- and measure-dependent. Results highlight the complex and interactive effects of muscle, task, and quantitative measures on between-group differences.

Effects of long-term tracheostomy on spectral characteristics of vowel production.

This study investigated the effects of long-term tracheostomy on the development of speech. Eight children who underwent tracheotomy during the prelingual period were compared to matched controls on selected spectral parameters of the speech acoustic signal and standard measures of oral-motor, phonologic, and articulatory proficiency. Analysis of formant frequency values revealed significant between-group differences. Children with histories of long-term tracheostomy showed reduced acoustic vowel space, as defined by group formant frequency values. This suggests that these children were limited in their ability to produce extreme vocal tract configurations for vowels (a,i,u) postdecannulation. Oral motor patterns were less mature, and sound substitutions were not only more variable for this group, but also reflected a persistent overlay of maladaptive compensations developed during cannulation.

Laryngeal electromyographic activity in adductor and abductor spasmodic dysphonia.

Vocal symptoms in spasmodic dysphonia (SD) range from strain-strangle phonation and glottal-stop phonatory breaks of adductor SD to breathy phonation and aspirate phonatory breaks of abductor SD. Many SD subjects show both symptom types. Heterogeneity in vocal symptoms contributes to controversy surrounding the etiology(s) of SD. Acoustic/perceptual analyses of vocal symptoms are inconclusive in resolving this controversy. This investigation moves the search for distinguishing features of adductor and abductor SD to the level of neuromuscular control and analysis of intrinsic laryngeal muscle (adductor and abductor) activity. Subjects rated perceptually as primarily adductor or abductor SD sustained production of vegetative gestures and isolated speech sounds (/i/ and /s/). Qualitative and quantitative analyses of electromyographic signals recorded from thyroarytenoid (TA) failed to differentiate SD subjects by symptom type. Analysis of TA and posterior cricoarytenoid (PCA) activity in one abductor SD revealed high levels in both muscles during production of the voiced vowel. Data suggest that a possible explanation for symptom heterogeneity in SD is the relation between disrupted neuromotor input to laryngeal muscles and reflexive or conscious compensations constrained by laryngeal biomechanics.

Regional cerebral blood flow in developmental stutterers.

Stuttering is a poorly understood communication disorder with a 1% global prevalence. Recently, there has been a resurgence of interest in a neurogenic origin for the disorder, although no research has established clear neurological differences between "developmental" (stuttering onset in childhood) stutterers and nonstutterers. We have used xenon 133 single-photon emission computed tomography to study regional cerebral blood flow (rCBF) in 20 stutterers. Analysis revealed global, absolute flow reductions. Relative flow asymmetries (left less than right) were identified in three hemispheric regions: anterior cingulate and superior and middle temporal gyri. Milder changes were found in the left inferior frontal gyrus. Stutterers had rCBF values below median for either anterior cingulate or middle temporal gyri. With one exception, severe stutterers had rCBF values below median for the anterior cingulate gyrus. All stutterers with rCBF values above median in the cingulate gyrus had rCBF values below median in the middle temporal gyrus, and severity of their disorder was either mild or moderate. Our findings suggest that stuttering is a neurogenic disorder involving recognized cortical regions of speech-motor control.

Laryngeal reaction time profiles in spasmodic dysphonia: relationship to cortical electrophysiologic abnormality.

This study combines measures of linguistic and vocal performance and long-latency auditory electrophysiology to investigate task-dependent variability in spasmodic dysphonia (SD). Linguistic performance was evaluated using several measures of relatively complex linguistic ability (i.e., discourse analysis). Vocal performance was evaluated by measuring acoustic laryngeal reaction time (LRT) for tasks that differ in complexity. Normal structure of the cortex and subcortex was confirmed by magnetic resonance imaging. Cortical function was measured using multichannel quantitative auditory evoked potentials (AEPs). As a group, SD subjects who demonstrated subtle linguistic deficits also demonstrated prolonged LRT for the complex task and repeated and persistent auditory electrophysiologic abnormalities over the anterior quadrant of the left hemisphere. As a group, linguistically normal SD subjects demonstrated no significant increase in LRT for the complex task and no recurrent electrophysiologic abnormalities over the left anterior cortex relative to normal controls. Results support a neurogenic origin of SD and suggest that some aspects of inter- and intrasubject variability may be related to differences in loci and magnitude of cortical abnormalities.

Preparation time and response complexity effects on stutterers' and nonstutterers' acoustic LRT.

Nonstutterers', mild stutterers', and severe stutterers' acoustic laryngeal reaction times (LRTs) were recorded for isolated vowels and nonpropositional VCV responses in different stimulus conditions governing response preparation. In all stimulus-response conditions severe stutterers produced the longest LRTs, followed in turn by mild stutterers and nonstutterers. The three groups significantly differed from one another in most conditions, but the magnitude of difference between mild and severe stutterers was notably greater than the difference between mild stutterers and nonstutterers. LRT changes as a function of stimulus condition showed that, in general, nonstutterers were best able to use a preparation-facilitating stimulus condition to reduce LRT, and severe stutterers least able to do so. LRT changes as a function of response complexity showed that only nonstutterers produced statistically significant within-group differences. Patterns of LRT change as a combined function of group, stimulus condition, and response type suggest a complex relationship between stutterer severity, preparation time, and type of response complexity. Results illustrate aspects of Goldberg's (1985) model of preparation processes, and support hypotheses that stutterer subgroups show differential preparation deficits along with high motor initiation variability.

Evidence for cortical dysfunction in spasmodic dysphonia: regional cerebral blood flow and quantitative electrophysiology.

Cortical function was evaluated in 26 subjects with spasmodic dysphonia. Quantitative topographic electrophysiologic mapping (QTE) was employed to provide quantitative analyses of EEG spectra and auditory and visual long-latency evoked potentials. Single-photon emission computed tomography (SPECT) of the cerebral transit of Xenon-133 was used to evaluate regional cerebral blood flow. Left hemispheric abnormalities in cortical function were found by both techniques in 10 subjects and by at least one technique in 18 subjects. Right hemispheric abnormalities were observed by both techniques in 8 subjects and by at least one technique in 18 subjects. Most patients with cortical dysfunction in one hemisphere had cortical dysfunction in the other, while only 4 subjects had unilateral lesions as found by one of the two techniques. Eight subjects were normal by all measurements. Underlying structural abnormalities were detected by magnetic resonance imaging in 5/24 subjects. However, functional abnormalities (SPECT or QTE) were not observed at sites of structural abnormalities. SPECT and QTE were significantly related in identification of left hemispheric dysfunction (p = .037) with a trend in the right hemisphere (p = .070), and a significant congruence of SPECT and QTE findings occurred in the left anterior cortical quadrant (p = .011). These findings indicate that dysfunction of cortical perfusion and/or cortical electrophysiology is associated with spasmodic dysphonia in the majority of subjects studied.

Measures of speech production.

The author discusses the mechanisms of speech production, focusing on the measurement of its motor aspects. He examines the multiple representation levels at which physiological events that underlie speech production can be investigated, and examines measurement of neuromuscular activity, structure movement (e.g. kinematics and dynamics), aerodynamic phenomena, and/or the acoustic output. He describes two general approaches. Studies can focus on one system and obtain data at multiple levels; for example, simultaneous recording of EMG (electromyogram) and/or kinematic signals, as well as the acoustic signal; this permits comprehensive assessment of physiologic events within a particular system. Alternatively, studies can obtain recordings of the acoustic signal simultaneously with EMG and/or kinematic signals taken from several systems; this permits assessment of the organization of physiologic events within, as well as between, systems. The author illustrates these methods in a study of stuttering.