1,039 research outputs found
Learning to breathe: control of the inspiratory–expiratory phase transition shifts from sensory‐ to central‐dominated during postnatal development in rats
No full textThe hallmark of the dynamic regulation of the transitions between inspiration and expiration is the timing of the inspiratory off-switch (IOS) mechanisms. IOS is mediated by pulmonary vagal afferent feedback (Breuer-Hering reflex) and by central interactions involving the Kolliker-Fuse nuclei (KFn). We hypothesized that the balance between these two mechanisms controlling IOS may change during postnatal development. We tested this hypothesis by comparing neural responses to repetitive rhythmic vagal stimulation, at a stimulation frequency that paces baseline breathing, using in situ perfused brainstem preparations of rats at different postnatal ages. At ages P15 was initially insignificant, but increased after repetitive vagal stimulation or lung inflation. This progressive adaption of PNA to the pattern of the sensory input was accompanied by the emergence of anticipatory centrally mediated IOS preceding the stimulus trains. The anticipatory IOS was blocked by bilateral microinjections of NMDA receptor antagonists into the KFn and PNA was immediately paced and entrained, as it was seen at ages < P15. We conclude that as postnatal maturation advances, synaptic mechanisms involving NMDA receptors in the KFn can override the vagally evoked IOS after 'training' using repetitive stimulation trials. The anticipatory IOS may imply a hitherto undescribed form of pattern learning and recall in convergent sensory and central synaptic pathways that mediate IOS
Hantzschia minima M. Rybak 2022, sp. nov.
No full textHantzschia minima M.Rybak sp. nov. (Figs 1–15, 46–52) LM observations (Figs 1–15): — Valves dorsiventral with straight or almost straight dorsal margin. Ventral margin weakly concave in middle, becoming slightly convex near apices.Apices abruptly protracted, small and clearly capitate, slightly deflected towards dorsal side. Valve dimensions (n=20): length 17.5–38.5 μm, width 3.5–4.5 μm. Fibulae 5–8 in 10 μm, unequally spaced, middle two fibulae clearly more distant. Striae equidistant, weakly radiate in middle, 22–25 in 10 μm. In some specimens, striae in valve middle slightly more spaced than others (Figs 10, 14). Areolae not discernible. SEM observations (Figs 46–52): — Valves on the ventral side bordered by a clearly thickened keel (Figs 46, 47). Striae composed of round areolae occluded by individual hymens. 49–60 in 10 µm (Figs 47, 51). External central raphe endings slightly deflected, very close together (Fig. 51). Distal raphe endings clearly hooked (Fig. 49). Internally central raphe endings deflected to opposite directions (Fig. 52). Striae forming narrow, deep, parallel grooves (Figs 48, 52). Each fibulae connected to 1–4 transapically costae (Fig. 48). Type:— Indonesia, Kairatu, West Seram, Molouki, 3°21’46.5”S 128°22’19.48”E, coll. date. 28 June 2018, holoslide no. SZCZ28484! and the unmounted material with the same number at the Szczecin Diatom Collection (University of Szczecin, Poland), iso - slide no. 2018/445 and the unmounted material with the same number at the University of Rzeszów, Poland. The type population is illustrated on Figs 1–15 and 46–52. Etymology:— The species epithet “ minima ” refers to its small size. Hantzschia minima sp. nov. is one of the smallest species in the genus. Distribution:— So far, the species was only observed from the type locality. Associated diatom flora:— The most abundant taxa in assemblage were: Hantzschia minima sp. nov., Humidophila contenta (Grunow) Lowe, Kociolek, Johansen, Van de Vijver, Lange-Bertalot & Kopalová (2014: 357), H. lacunosa (Moser, Lange-Bertalot & Metzeltin) Lowe et al. (2014: 358), Luticola intermedia (Hustedt) Levkov, Metzeltin & Pavlov (2013: 138), L. sublagerheimii Levkov, Metzeltin & Pavlov (2013: 229) and Pinnularia borealis Ehrenberg (1843: 420). The share of Hantzschia tokarczukiana sp. nov. did not exceed 5% in the assemblages.Published as part of Mateusz, Rybak, Natalia, Kochman-Kędziora & Muzaky, Luthfi Oktiyas, 2022, Four novel species from the genus Hantzschia Grunow (Bacillariophyta: Bacillariaceae) from rural areas of Southeast Asia, pp. 207-221 in Phytotaxa 567 (3) on pages 209-212, DOI: 10.11646/phytotaxa.567.3.1, http://zenodo.org/record/715665
Intra-and Inter-observer Agreement of High Resolution Antroduodenal Manometry in Pediatric Patients among Single Center Experts
No full textObjectives: Studies in adults have suggested that high-resolution technology increases the diagnostic yield of antroduodenal manometry (ADM). However, there is no study comparing high-resolution with low-resolution ADM recordings as well as comparing the 2 types of high-resolution display [conventional line plot (CLP) and pressure topographic plots (PTP)]. We hypothesized that high-resolution ADM is a superior diagnostic modality with higher inter-observer and intra-observer agreement compared with low-resolution recordings. Methods: Twenty-four anonymized ADM studies were blindly analyzed by 3 experienced pediatric neurogastroenterologists. All studies had been performed using a low-compliance water-perfused system with a 20-channels catheter. Data were displayed as CLP, as both high-resolution and low-resolution, and PTP in different sessions with at least 6-week interval. Accuracy was evaluated using previous established diagnosis and specific pre-prandial and post-prandial manometric patterns. Inter-observer and intra-observer agreements were calculated. Results: Analysis with high-resolution CLP revealed a substantial inter-observer agreement among the 3 observers regarding the diagnosis (Krippendorff's alpha: 0.832; average pairwise percentage agreement: 88.9%). Conversely, PTP and low-resolution CLP showed poor agreement for diagnoses (Krippendorff's alpha: 0.600; average pairwise percentage agreement: 75.3%; Krippendorff's alpha: 0.390; average pairwise percentage agreement: 60.2%, respectively). For the intra-observer agreement, Krippendorff's alpha ranges were 0.891-1 for CLP and 0.19393-0.34621 for PTP. Conclusions: Our study demonstrated higher diagnostic accuracy for high-resolution ADM compared to the low-resolution recordings. However, although it is well established for other motility investigations, PTP is not yet reliable in assessing foregut motor patterns. Advanced and more sophisticated software are clearly required for analyzing PTP display
Hantzschia malaysiana M. Rybak 2022, sp. nov.
No full textHantzschia malaysiana M.Rybak sp. nov. (Figs 28–37, 61–67) LM observations (Figs 28–37):— Valves distinctly dorsiventral appearing comparatively strongly silicified. Ventral margin slightly convex, dorsal margin slightly more convex in distal parts and concave in middle. Apices protracted, rostrate in small specimens becoming clearly capitate and deflected towards dorsal side in large specimens. Valve dimensions (n=20): length 55.0–130.0 μm, width 9.0–11.5 μm in middle to 9.5–12.0 μm in widest part of the valve face. Fibulae 5–7 in 10 μm, unequally spaced, two middle fibulae clearly more distant. Striae equidistant, weakly radiate in middle, 16–22 in 10 μm. Areolae not discernible. SEM observations (Figs 61–67):— Valves on ventral side bordered by a clearly thickened keel (Figs 61, 65). Striae composed of round areolae occluded by individual hymenes, 36–40 in 10 µm (Fig. 65), forming narrow, parallel grooves, between raised virgae (Figs 61, 65, 67). Striae on valve mantle organized same as on the valve face (Figs 65, 67). External central raphe endings deflected (Fig. 65). Distal raphe endings clearly hooked (Figs 61, 65). Internally, central raphe endings close to each other and deflected to same direction (Fig. 66). Distal raphe endings forming distinct helictoglossae (Fig. 64). Internally, fibulae not equidistant (Fig. 62). Each fibulae connected to 1–6 transapically costae (Fig. 62). Type:— Malaysia, Cameron highlands, Kuala Terla, 4°32’43”N 101°25’16”E, coll. date. 02 July 2016, holo - slide no. SZCZ28482! and the unmounted material with the same number at the Szczecin Diatom Collection (University of Szczecin, Poland), iso- slide no. 2016/51 and the unmounted material with the same number at the University of Rzeszow, Poland. The type population is illustrated on Figs 28–37 and 61–67. Etymology:— The species epithet refers to the type locality. Distribution:— So far, the species was only observed from the type locality. Associated diatom flora:— The most abundant taxa in the assemblage were: Hantzschia amphioxys (Ehrenberg) Grunow (in Cleve & Grunow 1880: 103), Humidophila contenta (Grunow) Lowe, Kociolek, Johansen, Van de Vijver, Lange-Bertalot & Kopalová (2014: 357), H. lacunosa (Moser, Lange-Bertalot & Metzeltin) Lowe, Kociolek, Johansen, Van de Vijver, Lange-Bertalot & Kopalová (2014: 358), H. aff. elegans (Moser, Lange-Bertalot & Metzeltin 1998: 144) Lowe, Kociolek, Johansen, Van de Vijver, Lange-Bertalot & Kopalová (2014: 358), Fallacia insociabilis (Krasske 1932: 114) D.G.Mann and Geissleria ignota (Krasske 1932: 116) Lange-Bertalot & Metzeltin (1996: 65), Luticola tomesii Moser, Lange-Bertalot & Metzeltin (1998: 198), L. intermedia (Hustedt) Levkov, Metzeltin & Pavlov (2013: 138), L. sublagerheimii Levkov, Metzeltin & Pavlov (2013: 229). Hantzschia malaysiana sp. nov. occurred rarely in analyzed material and only few specimens were observed on each slide.Published as part of Mateusz, Rybak, Natalia, Kochman-Kędziora & Muzaky, Luthfi Oktiyas, 2022, Four novel species from the genus Hantzschia Grunow (Bacillariophyta: Bacillariaceae) from rural areas of Southeast Asia, pp. 207-221 in Phytotaxa 567 (3) on pages 212-214, DOI: 10.11646/phytotaxa.567.3.1, http://zenodo.org/record/715665
Hantzschia beksinskii M. Rybak, Kochman-Kedziora 2022, sp. nov.
No full textHantzschia beksinskii M.Rybak, Kochman-Kędziora sp. nov. (Figs 38–45, 68–74) LM observations (Figs 38–45):— Valves distinctly dorsiventral appearing comparatively strongly silicified. Ventral margins slightly convex, dorsal margins convex in distal parts and concave in the middle. Apices protracted, rostrate and slightly deflected towards dorsal side. Valve dimensions (n=15): length 62.5–92.0 μm, width 7.5–10.5 μm in middle to 8.0–11.5 μm in widest part of valve face. Fibulae 5–6 in 10 μm, unequally spaced, middle two fibulae clearly more distant. Striae equidistant, weakly radiate in the middle, 18–21 in 10 μm. Areolae not discernible. SEM observations (Figs 68–74):— Valves on ventral side bordered by clearly thickened keel with shorted striae (with 2–3 areolae), which are separated from rest of valve face by longitudinal depression (Figs 68, 70, 74). Striae composed of round areolae occluded by individual hymenes, 35–40 in 10 µm (Figs 70, 74), forming narrow, deep, parallel grooves on valve face. Areolae near dorsal margin became more separated and not forming continuous grooves (Figs 68, 70, 74). Striae on valve mantle not forming parallel grooves, separated by not thickened virgae (Fig. 72). External central and distal raphe endings hooked (Figs 68, 70, 72). Internally, fibulae not equidistant (Fig. 69). Each fibulae connected to 1–5 transapically costae (Fig. 69). Central raphe endings deflected to same direction and clearly separated (Fig. 63). Distal raphe endings forming distinct helictoglossae (Figs 69, 71). Type:— Indonesia, Kepulauan Banda, Banda Neira, 4°30’16.98”S 129°53’57.01”E coll. date. 18 June 2018, holo - slide no. SZCZ28483! and the unmounted material with the same number at the Szczecin Diatom Collection (University of Szczecin, Poland), iso- slide no. 2018/432 and the unmounted material with the same number at the University of Rzeszow, Poland. The type population is illustrated on Figs 38–45 and 68–74. Etymology:— The species is named to honour Zdzisław Beksiński (1929–2005), a famous Polish painter, photographer and sculptor. Distribution:— So far, the species is only known from the type locality. Associated diatom flora:— The most abundant taxa in assemblage were: Hantzschia amphioxys (Ehrenberg) Grunow (in Cleve & Grunow 1880: 103), Humidophila pantropica (Lange-Bertalot) Lowe, Kociolek, Johansen, Van de Vijver, Lange-Bertalot & Kopalová (2014: 354), Pinnularia borealis Ehrenberg (1843: 420), and unidentified Adlafia sp. and Nitzschia sp. Hantzschia beksinskii sp. nov. occurred rarely in analyzed material and only few specimens were observed on each slide.Published as part of Mateusz, Rybak, Natalia, Kochman-Kędziora & Muzaky, Luthfi Oktiyas, 2022, Four novel species from the genus Hantzschia Grunow (Bacillariophyta: Bacillariaceae) from rural areas of Southeast Asia, pp. 207-221 in Phytotaxa 567 (3) on pages 215-217, DOI: 10.11646/phytotaxa.567.3.1, http://zenodo.org/record/715665
Algorithms for building products using 3D printing with cable-suspended robot
Get PDFRybak L. A. Algorithms for building products using 3D printing with cable-suspended robot / L. A. Rybak, D. I. Malyshev, E. V. Gaponenko // Adavnces in Engineering Reeseach (Actual Issues of Mechanical Engineering AIME 2017). - 2017. - Vol.133. - P. 696-701.The article presents algorithms for the control of a robotic complex for building products using 3D printing, including a module for the main movements and a module for precise movements based on a robot with a cable drive. The description of software modules for the implementation of algorithms and the technology of printing with the use of a printing module and a control unit for the supply of printing material are described. The basic principles of the operation of the program modules and the program interface are considered. There is a detailed selection of 3D print settings in the developed software module such as layer height, type of filling of the model with printing material, printing of supports, etc. Recommendations are given on the optimal choice of these settings to achieve the required quality of the obtained product models. The results of modeling are presented
World Multidisciplinary Civil Engineering-Architecture-Urban Planning Symposium - WMCAUS 2017
No full textPharmacological interventions for pediatric irritable bowel syndrome
No full textIntroduction: Irritable bowel syndrome is a common functional gastrointestinal disorder in children, characterized by recurrent abdominal pain associated with altered bowel habits in terms of both frequency and consistency. According to change in stool consistency it is categorized into 4 subtypes. From the etiological perspective, it is a combination of factors takes part in symptoms’ generation, the overall treatment response rate is often unsatisfactory if a multidisciplinary is not pursued. Areas covered: The aim of this manuscript is to summarize the current pharmacotherapy in pediatric irritable bowel syndrome in order to aid clinicians in treating this challenging disorder. Expert opinion: Most evidence involving pediatric populations rely on open label or retrospective studies and/or are not specifically designed for irritable bowel syndrome but tend to generalize their results to mixed populations of children with functional gastrointestinal disorders. A high placebo response rate combined with poor patients’ selection could account for the overall weak evidence supporting the use of pharmacological agents in pediatric irritable bowel syndrome. Given the multifaceted nature of the disorder, multidisciplinary approaches combining pharmacotherapy with alternative treatments is highly recommendable
Mechanisms of rhythmic bursting involving Na+ and Ca2+ in excitatory networks of brainstem and spinal cord: a modeling study
Get PDFThe rhythmic, synchronized bursting of neurons in a network is an important phenomenon that underlies many rhythmic behaviors such as breathing, locomotion, feeding, etc. The basic mechanisms of rhythmic bursting in excitatory networks are currently under debate in some areas of the brainstem and spinal cord, and controversies exist regarding the role of network interactions and cellular properties in their generation. We focus on a specific controversy concerning the role of the membrane currents persistent sodium (INaP) and the calcium-activated nonspecific cation current (ICAN) in network rhythms existing in brainstem slices containing the preBotzinger complex (preBotC), an important preparation relevant for understanding respiratory rhythm generation. We also address another type of rhythm existing in some of these preparations which has been proposed as fictive sighing. Using ideas suggested by and data gathered from experiments in this field, we constructed a mathematical, physiologically realistic model, which includes a description of cellular properties such as INaP, ICAN, Ca2+ current (ICa), the Na+/K+ pump current (IPump), IP3-mediated intracellular Ca2+ release, inactivation of INaP and intracellular Ca2+ release, and network properties such as synaptic coupling and excitatory drive to the network. Using this model, we investigated how the behavior of an isolated neuron depends on the relative expression of these properties, and how the behavior of a network of coupled neurons depends on the distribution of these properties across the network. We show that the role of a particular current such as INaP or ICAN in a network rhythm may depend on this distribution, and on the conditions of excitatory drive to and the overall strength of synaptic interactions in the network, offering a possible resolution of the controversy regarding the role of these currents in respiratory rhythm generation. We also propose a model of fictive sighing. Although our model was designed to address a specific controversy in a preparation of the brainstem concerned with repiratory rhythmogenesis, we expect that some of our results may be applicable to understanding the basic mechanisms of rhythmic bursting in excitatory networks in other areas of the brainstem and spinal cord.Ph.D., Biomedical Engineering -- Drexel University, 201
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