Lengthening Of Segments Research Articles

Final Lengthening and vowel length in 25 languages

Lengthening of segments at the end of prosodic domains is commonly considered a universal phenomenon, but language-specific variation has also been reported, specifically in languages with a phonological vowel length contrast. This cross-linguistic study uses spontaneous speech data from the DoReCo corpus as a testbed to investigate Final Lengthening (FL) in a diverse sample of 25 mostly understudied languages, thirteen of which have a phonological vowel length contrast. The duration of vowels was labeled using an automatic aligner, with additional manual corrections of word boundaries upon which refined segment alignments were created. The study reveals that (i) FL is a widespread process across languages; (ii) FL shows a wide variety of manifestations with respect to the degree and scope of lengthening; (iii) there are several significant interactions between phonological length and positional lengthening. These results lend support to theories assuming a phonological nature of Final Lengthening.

Foveal structure and visual function in nanophthalmos and posterior microphthalmos

Background/aimsThe reason for visual impairment in patients with nanophthalmos and posterior microphthalmos is not completely understood. Therefore, this study aims to investigate foveal structure, and the impact of demographic, clinical...

Experience-Dependent Development of Dendritic Arbors in Mouse Visual Cortex.

The dendritic arbor of neurons constrains the pool of available synaptic partners and influences the electrical integration of synaptic currents. Despite these critical functions, our knowledge of the dendritic structure of cortical neurons during early postnatal development and how these dendritic structures are modified by visual experience is incomplete. Here, we present a large-scale dataset of 849 3D reconstructions of the basal arbor of pyramidal neurons collected across early postnatal development in visual cortex of mice of either sex. We found that the basal arbor grew substantially between postnatal day 7 (P7) and P30, undergoing a 45% increase in total length. However, the gross number of primary neurites and dendritic segments was largely determined by P7. Growth from P7 to P30 occurred primarily through extension of dendritic segments. Surprisingly, comparisons of dark-reared and typically reared mice revealed that a net gain of only 15% arbor length could be attributed to visual experience; most growth was independent of experience. To examine molecular contributions, we characterized the role of the activity-regulated small GTPase Rem2 in both arbor development and the maintenance of established basal arbors. We showed that Rem2 is an experience-dependent negative regulator of dendritic segment number during the visual critical period. Acute deletion of Rem2 reduced directionality of dendritic arbors. The data presented here establish a highly detailed, quantitative analysis of basal arbor development that we believe has high utility both in understanding circuit development as well as providing a framework for computationalists wishing to generate anatomically accurate neuronal models.SIGNIFICANCE STATEMENT Dendrites are the sites of the synaptic connections among neurons. Despite their importance for neural circuit function, only a little is known about the postnatal development of dendritic arbors of cortical pyramidal neurons and the influence of experience. Here we show that the number of primary basal dendritic arbors is already established before eye opening, and that these arbors primarily grow through lengthening of dendritic segments and not through addition of dendritic segments. Surprisingly, visual experience has a modest net impact on overall arbor length (15%). Experiments in KO animals revealed that the gene Rem2 is positive regulator of dendritic length and a negative regulator of dendritic segments.

Misalignment of foveal pit and foveal bulge determined by ultrahigh-resolution SD-OCT in normal eyes.

The foveal bulge (FB) results from a lengthening of the outer segments of the photoreceptors which then makes the central fovea arcuate in shape. The purpose of this study was to evaluate the morphological features and locations of the FB relative to the foveal pit (FP) in a single B-scan image. One hundred and forty-seven eyes of 147 healthy volunteers were studied. Horizontal and vertical B-scan optical coherence tomographic (OCT) images through the fovea were recorded by an ultrahigh-resolution spectral domain OCT (UHR-SD-OCT) instrument (Bi-μ, KOWA, Japan). The vertex of the FB and the center of the FP were identified with the ImageJ software. The distance between the FB and FP and the height of the FB were measured. In the horizontal images, the vertex of the FB was on the nasal side of the center of the FP in 97 eyes (66%), on the temporal side in 42 eyes (29%), and the same position in 8 eyes (5%). In the vertical images, the vertex of the FB was superior to the center of the FP in 82 eyes (55%), inferior to the center of the FP in 45 eyes (31%), and the same position in 20 eyes (14%). The mean distance (± SD) between the FB and the FP was + 16.8 ± 30.1 μm in the horizontal images and + 8.27 ± 28.0 μm in the vertical images. The mean height (± SD) of the FB was 77.0 ± 4.78 μm in the horizontal images and 77.9 ± 5.05 μm in the vertical images. The height of the FB in the horizontal images was significantly correlated with refractive error in the multiple regression analysis (P = 0.041). These results indicate that the vertex of the FB was not aligned with the center of the FP in the majority of the eyes of normal Japanese individuals in a single B-scan image. Analysis showed that eyes with less severe myopia had the higher height of the FB. This must be considered when interpreting the location of the vertex of the FB and the center of the FP in clinical situations.

Anolis carolinensis as a model to understand the molecular and cellular basis of foveal development

The fovea is an anatomical specialization of the central retina containing closely packed cone-photoreceptors providing an area of high acuity vision in humans and primates. Despite its key role in the clarity of vision, little is known about the molecular and cellular basis of foveal development, due to the absence of a foveal structure in commonly used laboratory animal models. Of the amniotes the retina in birds of prey and some reptiles do exhibit a typical foveal structure, but they have not been studied in the context of foveal development due to lack of availability of embryonic tissue, lack of captive breeding programs, and limited genomic information. However, the genome for the diurnal bifoveate reptile species Anolis carolinensis (green anole) was recently published and it is possible to collect embryos from this species in captivity. Here, we tested the feasibility of using the anole as a model to study foveal development. Eyes were collected at various stages of development for histological analysis, immunofluorescence, and apoptosis. We show that at embryonic stage (ES) 10 there is peak ganglion cell density at the incipient central foveal region and a single row of cone photoreceptor nuclei. At ES17 the foveal pit begins to form and at this stage there are 3–4 rows of cone nuclei. Post-hatching a further increase in cone density and lengthening of inner and outer segments is observed. A yellowish pigment was seen in the adult central foveal region, but not in the temporal fovea. At ES14 Pax6 was localized across the entire retina, but was more prominent in the ganglion cell layer (GCL) and the part of the inner nuclear layer (INL) containing amacrine cell bodies. However, at ES17 Pax6 expression in the ganglion cells of the central retina was markedly reduced. Bioinformatic analysis revealed that 86% of human candidate foveal hypoplasia genes had an orthologous gene or DNA sequence in the green anole. These findings provide the first insight into foveal morphogenesis in the green anole and suggest that it could be a very useful model for investigating the molecular signals driving foveal development, and thus inform on human foveal development and disease.

Повторное удлинение голени как этап реконструкции ОДС пациентов с ахондроплазией

Objective To show that some achondroplasia cases of surgical locomotor reconstruction require repeated tibial lengthening to achieve optimal anthropometric parameters and review dynamics in reparative osteogenesis during repeated tibial lengthening using optical densitometry. Material and methods A group of patients who underwent double tibial lengthening included 25 achondroplasia and hypochondroplasia patients who underwent treatment at the Russian Ilizarov Scientific Centre “Restorative Traumatology and Orthopaedics” from 2000 to 2013. Results Review of dynamics in reparative osteogenesis revealed no specific course of the procedure. Conclusions Medical, ergonomic and esthetic aspects of achondroplasia treatment can partially be addressed by approaching anthropometric parameters to the biomechanical, ergonomic and esthetic standards through repeated lengthening of lower limb segments.

Feeding Kinematics and Nectar Intake of the Honey Bee Tongue

Most flower-visiting insects employ highly-evolved organs to feed themselves rapidly and efficiently on the floral nectar. A honey bee drives its segmented tongue (glossa) covered by dense hairs reciprocatingly to load nectar. A high-speed camera system ameliorated by a microscope revealed morphological changes in glossal surfaces during live honey bees’ nectar dipping and surface configurations through the stretching of postmortem honey bees’ glossae. Both the in vivo and postmortem observations reveal that shortening and lengthening of the glossal segments perform high concordance with the erection of glossal hairs, which aids in developing deformable gaps between rows of glossal hairs during nectar trapping. A model was proposed to evaluate the nectar-intake volume considering the experimentally-measured average erection angle and tongue elongation length during nectar feeding. The theoretical results fit the experimental data well and disclose that these two factors contribute to an augmentation of nectar-intake observably. We also theoretically present that the extendible and deformable glossae have advantages for the polylectic feeding behavior.

Repeated Mechanical Lengthening of Intestinal Segments in a Novel Model

Purpose: Currently, animal models used for mechanical intestinal lengthening utilize a single lengthening procedure prior to analysis or restoration back into continuity. Here we developed a novel surgical model to examine the feasibility of repeated lengthening of intestinal segments. Methods: A Roux-en-Y jejunojejunostomy with a blind Roux limb was created in rats. An encapsulated polycaprolactone spring was placed into a 1cm segment of the Roux limb. After 4weeks, a second encapsulated PCL spring was inserted into a 1cm portion of the lengthened segment. After another 4weeks, the repeatedly lengthened segments were retrieved for histological analyses. Results: Jejunal segments of the Roux limb were successfully lengthened from 1.0cm to 2.6±0.7cm. Four weeks after the second PCL spring placement, 1.0cm of the previously lengthened segment increased to 2.7±0.8cm. Stronger mechanical force was required to achieve subsequent re-lengthening. Lengthened and re-lengthened segments had increased smooth muscle thickness and crypt depth when compared to normal jejunal mucosa. Conclusion: Using the Roux-en-Y model, previously lengthened segments of intestine can be successfully re-lengthened. Intestinal segments may be subjected to multiple lengthening procedures to achieve clinically significant length for the treatment of short bowel syndrome.

A quantitative analysis of sign lengthening in American Sign Language

In spoken languages, disfluent speech, narrative effects, discourse information, and phrase position may influence the lengthening of segments beyond their typical duration. In sign languages, however, the primary use of the visual-gestural modality results in articulatory differences not expressed in spoken languages. This paper looks at sign lengthening in American Sign Language (ASL). Comparing two retellings of the Pear Story narrative from five signers, three primary lengthening mechanisms were identified: elongation, repetition, and deceleration. These mechanisms allow signers to incorporate lengthening into signs which may benefit from decelerated language production due to high information load or complex articulatory processes. Using a mixed effects model, significant differences in duration were found between (i) non-conventionalized forms vs. lexical signs, (ii) signs produced during role shift vs. non-role shift, (iii) signs in phrase-final/initial vs. phrase-medial position, (iv) new vs. given information, and (v) (non-disordered) disfluent signing vs. non-disfluent signing. These results provide insights into duration effects caused by information load and articulatory processes in ASL.

Development of an endoluminal intestinal lengthening capsule

Purpose Prior studies demonstrated the ability of a spring to lengthen intestinal segments. We made two innovations to this device. First, we employed a degradable capsule to control the deployment of the spring. Second, we decreased the spring force to allow slower expansion of the intestinal segment. Methods Nitinol springs with varying forces were compressed and placed in gelatin capsules. These capsules were coated with a degradable polymer and were placed in isolated segments of rat jejunum. Serial x-rays were used to determine the rate of spring expansion. Retrieved jejunal segments were analyzed histologically. Results Using the polymer-coated capsule, the spring was reliably deployed between 24 and 48 hours. Intestinal segments were lengthened from 1.0 cm to 3.6 cm after 14 days. The optimal spring for the gradual expansion of jejunal segments had a spring constant of 0.0010 N/mm. Villus height was preserved, but crypt depth was significantly greater in the lengthened intestine. Conclusion Use of a low-force spring resulted in a nearly four-fold lengthening of jejunal segments. The use of a polymer-coated capsule provided a reliable way to control the timing of spring deployment. This capsule may be useful for the endoscopic placement of the spring in patients with short bowel syndrome.

Electronic Enhancement Effect of Copper Modification of Base Pairs on the Conductivity of DNA

The effect of the new designed multicopper modification of base pairs on the conductivity of DNA was investigated by the nonequilibrium Green’s function method combined with density functional theory. Electronic transport calculations revealed that the equi-number H-by-Cu replacement can significantly enhance the conductivity of DNA from two aspects: transverse base-to-base communication along the hydrogen-bond direction and longitudinal transport along the DNA duplex. Furthermore, the enhancement effect on the longitudinal direction is more notable than that on the transverse. A tunneling mechanism is suggested for the short DNA segments. The decay factor of conductance in Cu-DNA decreases by half compared with the native DNA, thus making it more promising for constructing nanowires. In addition, Cu-DNA may prefer electron migration to hole transport with the lengthening of DNA segments. This work will shed some light on the design of promising DNA-based molecular wires.

Oxygen convective uptakes in gas exchange cycles in early diapause pupae of Pieris brassicae

Oxygen convective uptakes in gas exchange cycles were directly recorded in early diapause pupae of Pieris brassicae L. (Lepidoptera; Pieridae) by means of O2 coulometric respirometry. This method was combined with flow-through CO2 respirometry, the two systems being switchable one to the other. During recording with both systems, measurements were also taken with infrared actography. The pupae displayed short discontinuous gas exchange cycles lasting 40-70 min. No true C phase was found by flow-through measurements; instead, flutter opening of the spiracles with discrete convective O2 uptakes began shortly after the O phase whereas CO2 release was suppressed by the inward directed passive suction ventilation. The F phase was characterized by a series of small CO2 bursts (flutter events). Between these bursts, novel sub-phase `miniflutter' was observed, which consisted of six to 10 miniature inspirations without any CO2 emission. During the flow-through measurements, oxygen convective uptakes were indirectly recorded by the infrared actograph as sudden extensions (lengthening) of the abdominal segments at each spiracular microopening.

Masked Auditory Feedback Affects Speech Motor Learning of a Plosive Duration Contrast

Adult speakers have developed precise forward models of articulation for their native language and seem to rely less on auditory sensory feedback. However, for learning of the production of new speech sounds, auditory perception provides a corrective signal for motor control. We assessed adult German speakers' speech motor learning capacity in the absence of auditory feedback but with clear somatosensory information. Learners were presented with a nonnative singleton-geminate duration contrast of voiceless, unaspirated bilabial plosives /p/ vs. /pp/ which is present in Italian. We found that the lack of auditory feedback had no immediate effect but that deviating productions emerged during the course of learning. By the end of training, speakers with masked feedback produced strong lengthening of segments and showed more variation on their production than speakers with normal auditory feedback. Our findings indicate that auditory feedback is necessary for the learning of precise coordination of articulation even if somatosensory feedback is salient.

The effect of occluded auditory feedback on articulatory learning.

Auditory and somatosensory feedback are both claimed to be important for the acquisition and control of speech, especially during the learning of new speech sounds, where auditory feedback is said to provide a corrective signal for motor control. This study investigated adult speakers’ speech motor learning capacity in the absence of auditory feedback on a contrast which has clear somatosensory feedback. Thirty German speakers were trained to produce a non-native singleton-geminate contrast on voiceless unaspirated bilabial plosives: /p/ versus /pp/, as present in Italian. For half of the speakers, auditory feedback was completely blocked during training. Results indicate that although there is no immediate effect when auditory feedback is masked, deviating productions emerge during the course of learning. By the end of training, speakers with masked feedback produce strong lengthening of segments and show more variation in their production than speakers with auditory feedback. These results provide evidence that auditory feedback is necessary for the learning of precise coordination of articulation, and that even aspects of speech which are salient in somatosensory terms are monitored auditorily during the learning of a new speech sound contrast.

Intestinal lengthening in rats after massive small intestinal resection

Prior studies have demonstrated lengthening of normal small intestinal segments using mechanical expanders. The present study assesses the feasibility of intestinal lengthening in rats that have undergone extensive small intestinal resection. Female rats underwent small intestinal resection. After 6 weeks, the animals underwent the placement of a mechanical expander device with or without gradual mechanical lengthening. After 3 weeks, the intestinal segments were retrieved for analyses. Isolated intestinal segments without mechanical lengthening did not change in length, whereas isolated intestinal segments that were mechanically lengthened more than doubled their initial length. The total alkaline phosphatase activity was 2.4 mumol/min in the isolated intestinal segments and 4.9 mumol/min in the mechanically lengthened segments. The total lactase activity was 0.005 mumol/min in the isolated intestinal segments and 0.007 mumol/min in the mechanically lengthened segments. Smooth muscle thickness was 370 mum in the isolated intestinal segments and 530 mum in the mechanically lengthened segments. Mechanical small bowel lengthening was achieved in intestinal segments after extensive small intestinal resection. There was an increase in the total alkaline phosphatase activity and preservation of the total lactase activity. Mechanical lengthening may be a useful technique to increase intestinal length in patients with short bowel syndrome.

Locality interactions with prominence in determining the scope of phrasal lengthening

Temporal lengthening of gestures and segments located in a boundary-adjacent syllable has been found in both pre- and postboundary contexts. However, the temporal extent or scope of this lengthening, particularly in the articulatory domain, is not well described. We address the question of scope of prosodic lengthening by considering specifically whether prominence interacts with boundary-related articulatory lengthening in such a way that prominent elements not immediately at a phrase edge are lengthened relative to the same prominent elements phrase-medially (i.e. at a considerable distance from a boundary). Articulatory kinematic data were collected for three subjects to analyze consonant constrictions of prominent syllables located (1) either immediately before or after a boundary and (2) two and three syllables away from that boundary. The results indicate that, as expected, gestures undergo prosodic lengthening when immediately local to the phase boundary. However, some subjects did display prosodic lengthening at a small remove from the boundary for a prominent syllable. This effect was strongest in the postboundary condition. These results suggest that a consideration of prominence may be relevant in understanding the temporal patterning of boundary-related articulatory lengthening.

Visual Insignificance of the Foveal Pit

To elucidate the visual significance of the foveal pit by measuring foveal architecture and function and to reassess use of the term foveal hypoplasia (as visual acuity can vary among patients who lack a pit). We describe 4 patients who lack a foveal pit. Visual acuities ranged from 20/20 to 20/50. Stratus and Cirrus (Carl Zeiss Meditec, Dublin, California) optical coherence tomographs (OCTs) and multifocal electroretinograms were obtained. High-resolution retinal imaging on 2 of the participants was obtained by using a high-resolution Fourier-domain OCT and an adaptive optics flood-illuminated fundus camera. No participants had a visible foveal pit with conventional OCT. Central widening of the outer nuclear layer and lengthening of cone outer segments were seen with high-resolution Fourier-domain OCT. Adaptive optics imaging showed normal cone diameters in the central 1 degrees to 2 degrees. Central multifocal electroretinogram responses were normal. We show that a foveal pit is not required for foveal cone specialization, anatomically or functionally. This helps to explain the potential for good acuity in the absence of a pit and raises questions about the visual role of the foveal pit. Because the term foveal hypoplasia commonly carries a negative functional implication, it may be more proper to call the anatomic lack of a pit fovea plana.

Ethanol-related increases in degenerating bodies in the Purkinje neuron dendrites of aging rats

Chronic ethanol consumption in aging rats results in regression of Purkinje neuron (PN) dendritic arbors ([Pentney, 1995 Measurements of dendritic pathlengths provide evidence that ethanol-induced lengthening of terminal dendritic segments may result from dendritic regression. Alcohol Alcohol. 30, 87–96]), loss of synapses (Dlugos and Pentney, 1997), dilation of the smooth endoplasmic reticulum (SER), and the formation of degenerating bodies within PN dendrites ([Dlugos, C.A., 2006a. Ethanol-Related Smooth Endoplasmic Reticulum Dilation in Purkinje Dendrites of Aging Rats. Alcohol., Clin. Exp. Res. 30, 883–891,Dlugos, C.A., 2006b. Smooth endoplasmic reticulum dilation and degeneration in Purkinje neuron dendrites of aging ethanol-fed female rats. Cerebellum. 5, 155–162]). Dilation of the SER and the formation of degenerating bodies may be a predictor of dendritic regression. Ethanol-induced effects on mitochondria may be involved as mitochondria cooperate with the SER to maintain calcium homeostasis. The purpose of this study was to determine whether degenerating body number and mitochondrial density and structure are altered by chronic ethanol treatment in PN dendrites. Male, Fischer 344 rats, 12 months of age, were fed an ethanol or pair-fed liquid diet, or rat chow for a period of 10, 20, or 40 weeks (15 rats/treatment; 45 rats/treatment duration). Ethanol-fed rats received 35% of their calories as ethanol. At the end of treatment, all animals were euthanized, perfused, and tissue prepared for electron microscopy. The densities of degenerating bodies and mitochondria, mitochondrial areas, and the distance between the SER and the mitochondria were measured. Results showed that there was an ethanol-related increase in degenerating bodies compared to controls at 40 weeks. Ethanol-induced alterations to mitochondria were absent. Correlation of the present results with those of previous studies suggest that degenerating bodies may be formed from membrane reabsorption during dendritic regression or from degenerating SER whose function has been compromised by dilation.

Molecular Insights into Segmentation along the Proximal–Distal Axis of the Nephron

The structure of a mammalian kidney is parsed into large collections of polarized nephrons, and each segment is home to a diverse community of cells that specialize in renal endocrine and excretory functions. Early developmental lengthening and diversification of nephron segments along a proximal--distal axis initiate all subsequent facets of tubular growth and function. Morphogenic cues and biochemical interactions that are critical to this process are starting to emerge. The underlying principles of regional cell signaling and transcriptional control organizing early segmentation are the subject of this review.

Vocal-tract modeling: fractional elongation of segment lengths in a waveguide model with half-sample delays

Digital waveguide models are commonly used for simulating vocal-tract acoustics based on physiological data. In particular, waveguide models with half-sample delays are known to be well suited for speech production research. This paper presents enhancements to such a model, aimed at improved accuracy in mapping physiological vocal-tract data (shape and length of the airway) to waveguide parameters. The enhancements allow the length of the vocal tract to be continuously varied, thus enabling more realistic synthesis. This is achieved by smoothly varying the individual segment lengths of a piecewise-cylindrical representation of the airway, without altering the system sampling frequency. Fractional-delay filters are used for spatial interpolation of the digital waveguide model. The algorithms are validated by modeling the protrusion of lips, lowering of larynx and lengthening of intermediate segments for a static vowel shape