| 1. |
- Hakizimana, Pierre
(författare)
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The sensitivity of mechanoelectrical transduction response phase to acoustic overstimulation is calcium-dependent
- 2024
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Ingår i: Pflügers Archiv. - : SPRINGER HEIDELBERG. - 0031-6768 .- 1432-2013. ; 476:2, s. 271-282
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Tidskriftsartikel (refereegranskat)abstract
- The Mechanoelectrical transduction (MET) channels of the mammalian hair cells are essential for converting sound stimuli into electrical signals that enable hearing. However, the impact of acoustic overstimulation, a leading cause of hearing loss, on the MET channel function remains poorly understood. In this study, I investigated the effect of loud sound-induced temporary threshold shift (TTS) on the transduction response phase across a wide range of sound frequencies and amplitudes. The results demonstrated an increase in the transduction response phase following TTS, indicating altered transduction apparatus function. Further investigations involving the reduction of extracellular calcium, a known consequence of TTS, replicated the observed phase changes. Additionally, reduction of potassium entry confirmed the specific role of calcium in regulating the transduction response phase. These findings provide novel insights into the impact of loud sound exposure on hearing impairment at the transduction apparatus level and highlight the critical role of calcium in modulating sound transduction. Considering that over 1 billion teenagers and young adults globally are at risk of hearing loss due to unsafe music listening habits, these results could significantly enhance awareness about the damaging effects of loud sound exposure.
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| 2. |
- Jung, F, et al.
(författare)
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Respiratory entrainment of units in the mouse parietal cortex depends on vigilance state
- 2023
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Ingår i: Pflugers Archiv : European journal of physiology. - : Springer Science and Business Media LLC. - 1432-2013 .- 0031-6768. ; 475:1, s. 65-76
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Tidskriftsartikel (refereegranskat)abstract
- Synchronous oscillations are essential for coordinated activity in neuronal networks and, hence, for behavior and cognition. While most network oscillations are generated within the central nervous system, recent evidence shows that rhythmic body processes strongly influence activity patterns throughout the brain. A major factor is respiration (Resp), which entrains multiple brain regions at the mesoscopic (local field potential) and single-cell levels. However, it is largely unknown how such Resp-driven rhythms interact or compete with internal brain oscillations, especially those with similar frequency domains. In mice, Resp and theta (θ) oscillations have overlapping frequencies and co-occur in various brain regions. Here, we investigated the effects of Resp and θ on neuronal discharges in the mouse parietal cortex during four behavioral states which either show prominent θ (REM sleep and active waking (AW)) or lack significant θ (NREM sleep and waking immobility (WI)). We report a pronounced state-dependence of spike modulation by both rhythms. During REM sleep, θ effects on unit discharges dominate, while during AW, Resp has a larger influence, despite the concomitant presence of θ oscillations. In most states, unit modulation by θ or Resp increases with mean firing rate. The preferred timing of Resp-entrained discharges (inspiration versus expiration) varies between states, indicating state-specific and different underlying mechanisms. Our findings show that neurons in an associative cortex area are differentially and state-dependently modulated by two fundamentally different processes: brain-endogenous θ oscillations and rhythmic somatic feedback signals from Resp.
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| 3. |
- Ljungholm, Penny L., et al.
(författare)
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The anion exchanger slc26a3 regulates colonic mucus expansion during steady state and in response to prostaglandin E2, while Cftr regulates de novo mucus release in response to carbamylcholine
- 2024
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Ingår i: PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY. - 0031-6768 .- 1432-2013.
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Tidskriftsartikel (refereegranskat)abstract
- The intestinal epithelium is covered by mucus that protects the tissue from the luminal content. Studies have shown that anion secretion via the cystic fibrosis conductance regulator (Cftr) regulates mucus formation in the small intestine. However, mechanisms regulating mucus formation in the colon are less understood. The aim of this study was to explore the role of anion transport in the regulation of mucus formation during steady state and in response to carbamylcholine (CCh) and prostaglandin E-2 (PGE(2)). The broad-spectrum anion transport inhibitor 4,4 '-diisothiocyanatostilbene-2,2 '-disulfonate (DIDS), CftrdF508 (CF) mice, and the slc26a3 inhibitor SLC26A3-IN-2 were used to inhibit anion transport. In the distal colon, steady-state mucus expansion was reduced by SLC26A3-IN-2 and normal in CF mice. PGE(2) stimulated mucus expansion without de novo mucus release in wild type (WT) and CF colon via slc26a3 sensitive mechanisms, while CCh induced de novo mucus secretion in WT but not in CF colon. However, when added simultaneously, CCh and PGE(2) stimulated de novo mucus secretion in the CF colon via DIDS-sensitive pathways. A similar response was observed in CF ileum that responded to CCh and PGE(2) with DIDS-sensitive de novo mucus secretion. In conclusion, this study suggests that slc26a3 regulates colonic mucus expansion, while Cftr regulates CCh-induced de novo mucus secretion from ileal and distal colon crypts. Furthermore, these findings demonstrate that in the absence of a functional Cftr channel, parallel stimulation with CCh and PGE(2) activates additional anion transport processes that help release mucus from intestinal goblet cells.
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| 4. |
- Schaefer, Martin, et al.
(författare)
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Inconclusive evidence that breathing shapes pupil dynamics in humans : a systematic review
- 2023
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Ingår i: Pflügers Archiv. - : Springer Science and Business Media LLC. - 0031-6768 .- 1432-2013. ; :475, s. 119-137
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Forskningsöversikt (refereegranskat)abstract
- More than 50 years ago, it was proposed that breathing shapes pupil dynamics. This widespread idea is also the general understanding currently. However, there has been no attempt at synthesizing the progress on this topic since. We therefore conducted a systematic review of the literature on how breathing affects pupil dynamics in humans. We assessed the effect of breathing phase, depth, rate, and route (nose/mouth). We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and conducted a systematic search of the scientific literature databases MEDLINE, Web of Science, and PsycInfo in November 2021. Thirty-one studies were included in the final analyses, and their quality was assessed with QualSyst. The study findings were summarized in a descriptive manner, and the strength of the evidence for each parameter was estimated following the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. The effect of breathing phase on pupil dynamics was rated as “low” (6 studies). The effect of breathing depth and breathing rate (6 and 20 studies respectively) were rated as “very low”. Breathing route was not investigated by any of the included studies. Overall, we show that there is, at best, inconclusive evidence for an effect of breathing on pupil dynamics in humans. Finally, we suggest some possible confounders to be considered, and outstanding questions that need to be addressed, to answer this fundamental question. Trial registration: This systematic review has been registered in the international prospective register of systematic reviews (PROSPERO) under the registration number: CRD42022285044.
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| 5. |
- Andersson, Kerstin, 1961-
(författare)
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Molecular properties of TCNQ and anions
- 2023
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Ingår i: Theoretical Chemistry accounts. - : Springer. - 1432-881X .- 1432-2234. ; 142:6
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of the work is to calculate accurate values of molecular properties of tetracyanoquinodimethane (TCNQ) and anions using the complete active space self-consistent field and complete active space second-order perturbation theory methods. The accuracy has been evaluated using several basis sets and active spaces. The calculated properties have, in many cases, been confirmed by experimental data (within parentheses), e.g., 9.54 eV (9.61 eV) and 3.36 eV (3.38 eV) for the ionization potential and electron affinity, respectively, of TCNQ; 3.12 eV (3.01 eV) and 3.54 eV (3.42 or 3.60 eV) for transition energies to the two lowest-lying excited singlet states of TCNQ; − 0.03, 0.46 and 1.44 eV (0, 0.5 and 1.4 eV) for electronic energies in electron attachment of TCNQ forming $$\hbox {TCNQ}^-$$; and 3.88 eV (3.71 eV) for the transition energy to the second lowest-lying excited singlet state of $$\hbox {TCNQ}^{2-}$$. Further, the calculations have brought insight into some experimental observations, e.g., the shape of the fluorescence spectrum of TCNQ at 3–4 eV.
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| 6. |
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| 7. |
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| 8. |
- Bernhoff, Niclas, 1971-, et al.
(författare)
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On the Boundary Layer Equations with Phase Transition in the Kinetic Theory of Gases
- 2021
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Ingår i: Archive for Rational Mechanics and Analysis. - : Springer-Verlag New York. - 0003-9527 .- 1432-0673. ; 240:1, s. 51-98
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Tidskriftsartikel (refereegranskat)abstract
- Consider the steady Boltzmann equation with slab symmetry for a monatomic, hard sphere gas in a half space. At the boundary of the half space, it is assumed that the gas is in contact with its condensed phase. The present paper discusses the existence and uniqueness of a uniformly decaying boundary layer type solution of the Boltzmann equation in this situation, in the vicinity of the Maxwellian equilibrium with zero bulk velocity, with the same temperature as that of the condensed phase, and whose pressure is the saturating vapor pressure at the temperature of the interface. This problem has been extensively studied, first by Sone, Aoki and their collaborators, by means of careful numerical simulations. See section 2 of (Bardos et al. in J Stat Phys 124:275–300, 2006) for a very detailed presentation of these works. More recently, Liu and Yu (Arch Ration Mech Anal 209:869–997, 2013) proposed an extensive mathematical strategy to handle the problems studied numerically by Sone, Aoki and their group. The present paper offers an alternative, possibly simpler proof of one of the results discussed in Liu and Yu (2013).
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| 9. |
- Svedberg, Lars, et al.
(författare)
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Networking among deputy superintendents – Window dressing or navigating complexity?
- 2024
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Ingår i: Educational Management Administration & Leadership. - : Sage Publications. - 1741-1432 .- 1741-1440.
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Tidskriftsartikel (refereegranskat)abstract
- External networks among deputy superintendents seem to be an increasing phenomenon in a sector that faces a rapid change and a high working load. Is this the new way to learn and improve the organization or just a social gathering with little value? In this study, the significance of networking among deputy superintendents is explored. This group of middle managers is less studied compared to superintendents. The following questions have guided the study: How are their networks designed? What themes and issues do they focus on? What networks are considered relevant? The data for this study were collected through a survey of participants in a seminar series arranged by the Swedish National Professional Association for Superintendents. Networking appears to blend operational, personal, and strategic issues, intertwining practical matters with personal and professional growth to address present challenges and future requirements. Even if networking is seen as less formal it requires individual engagement as it is embedded in a process to become a professional space that benefits both the individual and the school organization. Networks appear to provide essential resources for navigating the complexities embedded in tangled logics and the frequently unpredictable processes that follow.
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| 10. |
- Ahmed, Bestoun S., 1982-, et al.
(författare)
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An evaluation of Monte Carlo-based hyper-heuristic for interaction testing of industrial embedded software applications
- 2020
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Ingår i: Soft Computing - A Fusion of Foundations, Methodologies and Applications. - : Springer. - 1432-7643 .- 1433-7479. ; 24:18, s. 13929-13954
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Tidskriftsartikel (refereegranskat)abstract
- Hyper-heuristic is a new methodology for the adaptive hybridization of meta-heuristic algorithms to derive a general algorithm for solving optimization problems. This work focuses on the selection type of hyper-heuristic, called the exponential Monte Carlo with counter (EMCQ). Current implementations rely on the memory-less selection that can be counterproductive as the selected search operator may not (historically) be the best performing operator for the current search instance. Addressing this issue, we propose to integrate the memory into EMCQ for combinatorial t-wise test suite generation using reinforcement learning based on the Q-learning mechanism, called Q-EMCQ. The limited application of combinatorial test generation on industrial programs can impact the use of such techniques as Q-EMCQ. Thus, there is a need to evaluate this kind of approach against relevant industrial software, with a purpose to show the degree of interaction required to cover the code as well as finding faults. We applied Q-EMCQ on 37 real-world industrial programs written in Function Block Diagram (FBD) language, which is used for developing a train control management system at Bombardier Transportation Sweden AB. The results show that Q-EMCQ is an efficient technique for test case generation. Addition- ally, unlike the t-wise test suite generation, which deals with the minimization problem, we have also subjected Q-EMCQ to a maximization problem involving the general module clustering to demonstrate the effectiveness of our approach. The results show the Q-EMCQ is also capable of outperforming the original EMCQ as well as several recent meta/hyper-heuristic including modified choice function, Tabu high-level hyper-heuristic, teaching learning-based optimization, sine cosine algorithm, and symbiotic optimization search in clustering quality within comparable execution time.
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