bluuebunny/crossref_metadata_2025 huggingface dataset:
Informal Written Language Analysis Methods: Case Examples of Adults With Traumatic Brain Injury
Authors: Dinnes Carly R. , Hux Karen
Published: December 2021

Purpose:

Written expression challenges following traumatic brain injury (TBI) in adults have received little clinical attention but can substantially affect quality of life and the success of reintegration efforts. Assessment tools and procedures are lacking despite the likelihood of post-TBI problems with microstructure (e.g., productivity, spelling accuracy) and macrostructure (e.g., topic adherence, organization) aspects of written language. The lack of standardized procedures forces reliance on informal methods to determine writing strengths and challenges.

Method:

A combination of assessment procedures allowed for evaluation of the productivity and efficiency, adherence to writing conventions (e.g., spelling, sentence structure, punctuation), and macrostructure organization (e.g., story grammar, topic adherence) of written narratives collected from five adults with TBI.

Results:

Use of multiple assessment methods revealed disparate writing challenges across the five case examples. The differing writing profiles underscore the necessity of evaluating multiple aspects of written narratives.

Conclusions:

The described analysis methods can help clinicians determine areas of strength and challenge in written work generated by adults with TBI. Examination of multiple aspects of writing is key to garnering a comprehensive appraisal of post-TBI writing.
Is There a Cognate Effect in Bilingual Children With Developmental Language Disorder?
Authors: Payesteh Bita , Pham Giang T.
Published: December 2021

Purpose:

Cognates, words in two languages that share form and meaning, can be used to support vocabulary development in bilingual children. Typically developing bilinguals have shown better performance on cognates versus noncognates. Of key interest is whether bilinguals with developmental language disorder (DLD) also show a cognate effect and, if so, which factors are related to their cognate performance.

Method:

Thirty-five Spanish–English bilingual children (5–11 years old) with DLD completed the Expressive and Receptive One-Word Picture Vocabulary Tests, third edition, in English (EOW, ROW) to measure cognate performance. Test items were divided by difficulty level (easy, medium, and hard) and classified as cognates or noncognates using the Cross-Linguistic Overlap Scale for Phonology.

Results:

On average, children showed clear and robust cognate effects on EOW across difficulty levels with medium-to-large effect sizes. Results on the ROW showed minimal effects that varied by difficulty. Individually, 80% of participants (28 of 35) demonstrated a cognate effect in EOW, whereas only 31% (11 of 35) showed an effect in ROW. A cognate effect in ROW was positively correlated with age and English proficiency, whereas no factors correlated with the EOW cognate effect.

Conclusions:

Bilingual children with DLD show higher performance on cognates than noncognates, at least in expressive vocabulary. Participants who did show a receptive cognate effect tended to be older and have higher English proficiency. Further investigation is needed to identify factors underlying cognate performance in order to tailor intervention strategies that promote bilingual vocabulary development.
An episodically variable stellar wind in the planetary nebula IC 4997
Authors: Miranda Luis F. , Torrelles José M. , Lillo-Box Jorge
Published: December 2021

IC 4997 is a planetary nebula well known by its variability. We present high-resolution spectra of IC 4997 obtained in 1993, 2019, and 2020 that reveal changes in the Hα and [N II] emission line profiles, which had never been reported for this object. The Hα P Cygni emission profile observed in 1993 changed to a single-peaked profile in 2019−2020, implying that the stellar wind has largely weakened. The very broad Hα emission wings narrowed by a factor of ∼2 between 1993 and 2019−2020, indicating that the efficiency of the Rayleigh–Raman scattering has noticeably decreased. A high-velocity [N II] nebular component detected in 1993 is missing in 2019 and 2020, probably due to a decrease in its electron density. A correlation exists between the strength of the stellar wind and the episodic (∼50−60 yr) variation in the [O III]λ4363/Hγ line intensity ratio, suggesting that an episodic, smoothly variable stellar wind is the main cause of the variability of IC 4997. Monitoring of that intensity ratio and of the Hα emission line profile in the coming years and new multiwavelength observations are key to unveiling the ongoing processes in IC 4997 and constraining the origin of the wind variability.
Time-resolved evolution of plasma parameters in a plasma immersion ion implantation source
Authors: Moreno J. , Khodaee A. , Okerstrom D. , Bradley M. P. , Couëdel L.
Published: December 2021

The origin and nature of perturbations induced by a high-voltage pulse on plasma parameters and their relationship to operating conditions (power and pressure) in an argon inductively coupled radio frequency plasma device is explored. The plasma parameters are measured with two radio frequency compensated Langmuir probes positioned either vertically above the pulsing target or horizontally along the diameter of the chamber, in the same axial plane as the target and same distance from the RF antenna. Fluctuations are observed in electron density ne, temperature Te, and plasma potential Vpl following negative polarity high voltage pulses and propagate deep in the plasma and well after the end of the pulse. Time-resolved data results indicate that the perturbations are significantly dampened at higher power as well as when closer to the plasma RF coil. The perturbation amplitudes depart significantly from steady state values when the pulse amplitude exceeds 2.0 kV and increase with the increasing pulse amplitude. Perturbation amplitudes are also higher for target materials having larger secondary electron yield. Our experimental results suggest that the underlying mechanism of this perturbation could be plasma heating driven by damping of a beam-plasma instability as a result of a beam of secondary electrons emitted by the target streaming into the plasma.
The role of entropy in the success of nonstoichiometric oxides for two-step thermochemical water and CO2 splitting
Authors: Lenarduzzi Gianpaolo , Cooper Thomas A.
Published: December 2021

Owing to their high theoretical efficiency, two-step solar thermochemical water and CO2 splitting cycles, using a metal oxide intermediate, provide a promising pathway to store solar energy in a stable chemical bond. To date, the most successful demonstrations have utilized nonstoichiometric oxides, a class of materials capable of continuously transitioning from an oxidized to reduced state via formation of oxygen vacancies. The success of nonstoichiometric oxides is typically attributed to their ability to maintain their crystallographic phase, allowing them to be cycled many times without destabilizing–a tremendous practical advantage. In this work, we utilize a combined empirical and statistical thermodynamics approach to present an alternative explanation of the success of nonstoichiometric oxides from an entropy perspective. We first illuminate the importance of the entropy change of the reduction reaction as a key material parameter. We then develop a methodology for plotting nonstoichiometric oxides on the Ellingham diagram, enabling a direct comparison to stoichiometric materials. This analysis reveals the unique ability of nonstoichiometric oxides to achieve a significant solid-state entropy contribution, which results from the disorder generated via oxygen vacancy formation. To quantify the solid-state entropy, we develop a simple configurational entropy model applicable to any oxygen-deficient nonstoichiometric oxide. We compare model predictions to existing data for two important nonstoichiometric oxides, CeO2−δ and La0.6Ca0.4Mn0.6Al0.4O3−δ, to reveal the main trends in entropy vs δ and material composition and discuss the causes and implications of deviations from the theory.
Improvement of the frequency stability of the cesium fountain clock by data processing
Authors: Li Zhiqi , Yang Ning , Liu Suyan , Zhou Wei
Published: December 2021

The cesium fountain clock is used as the primary frequency standard to improve the accuracy of the excitation source (active hydrogen maser) through cesium atomic transition frequency. The authors find that the frequency stability of cesium fountain clock is poorer than the active hydrogen maser according to the laws of the frequency stability evaluated by the Allan variance. The cesium fountain frequency stability can only reach 2 × 10−15 after 10 000 s. The traditional stability improvement methods are based on the Ramsey line-width optimization. The correction signal of fountain clock contains error, which can be removed partly by data correction. A new method to improve the frequency stability by modified error factor with statistical theory is presented in this paper. The results of frequency stability can reach 1.03 × 10−14/2 s and 2.78 × 10−16/16 400 s.
Driving rotamak currents with minimal power dissipation
Authors: Van De Wetering J. J. , Fisch N. J.
Published: December 2021

The Rotamak is a proposed thermonuclear fusion device which employs rotating magnetic fields (RMF) to generate an azimuthal current to produce a field-reversed configuration. The efficiency of the currents that produce the field reversal by RMFs was debated some 40 years ago. The debate revolved around whether the currents would incur dissipation by the conventional Spitzer perpendicular resistivity, or whether some other relation between current and dissipation would be more appropriate. By employing an electron–ion pitch-angle scattering model, we find that the dissipation is non-Spitzer in nature. However, curiously, there appears to exist a regime where the power dissipated to maintain the current becomes vanishingly small.
Effects of initial surfactant concentration on plasma-induced liquid flows
Authors: Kawasaki Toshiyuki , Kamasaki Masahiro , Takeuchi Nozomi , Mitsugi Fumiaki
Published: December 2021

Clarifying the mechanisms of liquid flows induced by plasma irradiation is necessary to understand the plasma–liquid interaction. In the present work, we studied the effects of the initial surfactant (lauryl betaine) concentration on the plasma-induced liquid flows using particle image velocimetry. The results indicated that the initial surfactant concentration affected the generation characteristics of a liquid flow that linearly moved in the depth direction of the liquid. The intensity of the driving force strongly depended on the initial surfactant concentration and varied with the plasma-irradiation time. At a concentration of 20 mg/l, the liquid flow changed in the opposite direction during plasma irradiation. In the concentration range of 50–150 mg/l, the liquid flows were mostly enhanced in the same direction. The liquid flows became extremely weak in the surfactant solution above a critical micelle concentration (approximately 400 mg/l). We focused on the Marangoni flow generated by a surface-tension gradient as the driving force. The surface tension was measured before and after plasma irradiation. The difference in the surface tension due to plasma irradiation was also maximum in the concentration range of 50–150 mg/l. The experimental results demonstrated that the change in the surface-tension difference due to plasma irradiation was strongly related to the direction and intensity of the liquid flows. The mechanisms of the plasma-induced liquid flows were qualitatively explained in relation to the initial surfactant concentration.
Macroscopic turbulent kinetic energy budget in flow through a wall-bounded compact bank of cylinders
Authors: Nawab A. , diMare L.
Published: December 2021

The flow in devices, such as heat exchangers, can be idealized as turbulent flow past an array of regularly spaced obstacles. Engineering calculations in such devices are easily handled if the flow can be represented by its volume-average quantities. This paper reports an investigation into the volume-averaged flowfield in a regular array of cylinders of finite height in crossflow at two Reynolds numbers (ReD). The investigation is based on scale-resolving computations and is thus the first to analyze the true form of the macroscopic turbulent kinetic energy (TKE) conservation law in the presence of macroscopic shear. Volume-averaging is performed parallel to the end walls in order to obtain profiles of macroscopic flow quantities. In inner coordinates, the macroscopic velocity profiles are similar to the canonical turbulent channel flow profiles, but with different values of the von Kármán constant and log-law y-intercept. The volume-averaged TKE is defined so as to include contributions from both the macroscopic and microscopic components of the flow. While the macroscopic TKE profile is very different to that of channel flow, the macroscopic TKE budget terms are remarkably similar. One notable exception is that the production rate stays large throughout the domain rather than attenuating rapidly after a near-wall peak. An extension to a widely used macroscopic turbulence model is proposed, which enables it to match the volume-averaged TKE production rate predicted by the large eddy simulations.
Solving the time-independent Schrödinger equation for chains of coupled excitons and phonons using tensor trains
Authors: Gelß Patrick , Klein Rupert , Matera Sebastian , Schmidt Burkhard
Published: December 2021

We demonstrate how to apply the tensor-train format to solve the time-independent Schrödinger equation for quasi-one-dimensional excitonic chain systems with and without periodic boundary conditions. The coupled excitons and phonons are modeled by Fröhlich–Holstein type Hamiltonians with on-site and nearest-neighbor interactions only. We reduce the memory consumption as well as the computational costs significantly by employing efficient decompositions to construct low-rank tensor-train representations, thus mitigating the curse of dimensionality. In order to compute also higher quantum states, we introduce an approach that directly incorporates the Wielandt deflation technique into the alternating linear scheme for the solution of eigenproblems. Besides systems with coupled excitons and phonons, we also investigate uncoupled problems for which (semi-)analytical results exist. There, we find that in the case of homogeneous systems, the tensor-train ranks of state vectors only marginally depend on the chain length, which results in a linear growth of the storage consumption. However, the central processing unit time increases slightly faster with the chain length than the storage consumption because the alternating linear scheme adopted in our work requires more iterations to achieve convergence for longer chains and a given rank. Finally, we demonstrate that the tensor-train approach to the quantum treatment of coupled excitons and phonons makes it possible to directly tackle the phenomenon of mutual self-trapping. We are able to confirm the main results of the Davydov theory, i.e., the dependence of the wave packet width and the corresponding stabilization energy on the exciton–phonon coupling strength, although only for a certain range of that parameter. In future work, our approach will allow calculations also beyond the validity regime of that theory and/or beyond the restrictions of the Fröhlich–Holstein type Hamiltonians.
Observation of multilayer-structured discharge in plasma ionization breakdown
Authors: Wen De-Qi , Zhang Peng , Krek Janez , Fu Yangyang , Verboncoeur John P.
Published: December 2021

In this Letter, a multilayer-structured discharge (MSD) is reported in multipactor-coexisting plasma ionization breakdown by fully kinetic particle-in-cell simulations. The observed multilayer structure is originated by the response of ions to an electric field. It is found that the electron diffusion and multipactor discharge near the surface produce two opposite electric fields toward and away from the dielectric surface, respectively. Thus, the ions form a locally high density profile, which is followed by electron density. The lighter electrons diffuse away from the peak more quickly than the ions, resulting in an ambipolar field toward the bulk plasma region, which drives the ion density peak to propagate toward the bulk plasma. Such a process is periodically repeated, and, finally, a MSD is formed.
Inhomogeneous defect distribution of triangular WS2 monolayer revealed by surface-enhanced and tip-enhanced Raman and photoluminescence spectroscopy
Authors: Miao Peng , Chen Yu-Ting , Pan Lin , Horneber Anke , Greulich Katharina , Chassé Thomas , Peisert Heiko , Adam Pierre-Michel , Xu Ping , Meixner Alfred , Zhang Dai
Published: December 2021

Confocal optical microscopy and tip-enhanced optical microscopy are applied to characterize the defect distributions in chemical vapor deposition-grown WS2 monolayer triangles qualitatively and quantitatively. The presence of defects in individual monolayer WS2 triangles is revealed with diffraction-limited spatial resolution in their photoluminescence (PL) images, from which the inhomogeneous defect density distribution is calculated, showing an inverse relationship to the PL intensity. The defect-related surface-enhanced Raman spectroscopy (SERS) effect is investigated by depositing a thin copper phthalocyanine layer (5 nm) as the probe molecule on the monolayer WS2 triangles surface. Higher SERS enhancement effects are observed at the defect-rich areas. Furthermore, tip-enhanced optical measurements are performed, which can reveal morphologically defected areas invisible in the confocal optical measurements. Furthermore, the area with high defect density appears brighter than the low-defected area in the tip-enhanced optical measurements, which are different from the observation in the confocal optical measurements. The underlying reasons are attributed to the near-field enhancement of the defect exciton emission induced by the optically excited tip and to an improved coupling efficiency between the tip-generated near-field with the altered dipole moment orientation at the local defect.
Static Bending Analysis of Small-Sized Structures Using Various Non-Classical Theories
Authors: Civalek Ömer , Numanoğlu Hayri Metin , Dastjerdi Shahriar , Akgöz Bekir
Published: December 2021

In this chapter, the size-dependent static bending response of microbeams is investigated based on modified couple stress and modified strain gradient elasticity theories. In contrast to the classical beam model, the present non-classical beam models contain length-scale parameters and can capture the size effect. If the length-scale parameters are equal to zero, these models transform to the classical one. The equilibrium equations with classical and non-classical corresponding boundary conditions for microbeams are derived by implementing the principle of minimum total potential energy based on the modified couple stress and modified strain gradient theories in conjunction with the Bernoulli–Euler beam theory. The resulting higher-order equation is analytically solved for simply supported (S–S), clamped–free (C–F), clamped–hinged (C–H), and clamped–clamped (C–C) boundary conditions. Finally, some illustrative examples are given to investigate the effects of the length-scale parameters, size dependency, and boundary conditions on the displacements of the small-sized beams. It is observed that the size effect is more prominent for the larger length-scale parameters. In addition, it is found that the divergence between displacements evaluated by the present and classical models becomes more significant for smaller beams.
Static Analysis of Euler–Bernoulli Nanobeams Including the Surface Effects Using the Differential Quadrature Method
Authors: Karmakar Somnath , Chakraverty Snehashish
Published: December 2021

In this chapter, static bending of an Euler nanobeam with surface effects is considered. The governing equation of vibration is derived with the help of Eringen's nonlocal theory. The differential quadrature method is applied to solve the differential equations. Different classical boundary conditions and surface effects are considered to address the titled problem.
Dynamic Structural Evolution of Nanocrystalline Aluminum During Ratcheting Deformation
Authors: Narendra Babu Pokula , Reddy K. Vijay , Pal Snehanshu
Published: December 2021

The ratcheting deformation mechanism and dislocation behavior at the grain boundary (GB) of nanocrystalline (NC) aluminum (Al) with a grain size of ∼8 nm are investigated by molecular dynamics simulations at various temperatures (i.e., 77 K, 300 K, and 560 K). The structural evolution and dislocation nature are studied at the atomic level during ratcheting deformation. This study reveals that dislocation–dislocation interactions cause stacking faults and twin boundary formation in NC Al specimens subjected to low-cycle fatigue loading conditions. Ratcheting strain accumulation augments as the NC Al specimen undergoes more ratcheting deformation cycles. The dislocation density is observed to be comparatively high if the deformation occurs at cryogenic temperature. The dislocation mobility, dislocation loop formations, and dislocation entanglements are observed during the ratcheting process. The total Shockley partial dislocation cumulative length is increased as the ratcheting deformation progresses. Shockley partial and perfect dislocations are the significant contributors to the ratcheting deformation process in the case of ultrafine grain NC Al. Correspondingly, the post-processing analysis work of ratcheting deformation behavior is performed with the common neighbor analysis, atomic strain, dislocation analysis, Wigner–Seitz defect analysis, and centrosymmetry parameter tools of the OVITO software.
A View From Physics
Authors: McDermott Lillian C.
Published: December 2021

A View From Physics: Discipline-Based Education Research presents the author’s account as one of the founders of the field of physics education research, the scientific study of the teaching and learning of physics. The hallmark of this relatively new field is the use of rigorous analytical and quantitative study to develop more effective curriculum and validate its efficacy.

This unique title features:The founder’s personal history of building the world-renowned Physics Education Group at the University of Washington, Seattle, Washington, USAAn outline of the growth of physics education research, including discussions of current topicsA chronicle of the author’s pioneering career as one of the few women in physics during the mid-20th century and her lasting impact on physics education

A View From Physics: Discipline-Based Education Research offers insights and perspectives for university physics faculty, physics education researchers, secondary school physics/physical science teachers, and those interested in science education more broadly. This book is also for those interested in the history of women in science.
Inspiration and Reflections: Teachers speak about the Physics for Teachers Program at UW
Authors: McDermott Lillian C.
Published: December 2021

The preceding chapters address how the Physics Education Group (PEG) at the University of Washington (UW) has contributed to understanding and improving K–12 science teaching through generating research and developing and implementing the curriculum. However, the picture would be incomplete without hearing directly from the teachers who have been integral to this iterative process. This chapter conveys, in their own words, the reflections of teachers and instructors at different levels on how their engagement with the PEG influenced their views, their teaching methods, and their careers, often in transformative ways.
Diagnostic vocal fold injection as an intervention for secondary muscle tension dysphonia
Authors: Dwyer Christopher D. , Carroll Thomas L.
Published: December 2021

Objectives

In this review, we draw on the available evidence supporting use of a diagnostic vocal fold injection as part of the treatment paradigm for secondary muscle tension dysphonia when voice therapy incompletely addresses patient’s voice and laryngeal related symptoms. We aim to outline some key diagnostic and treatment considerations, focussing on the search for underlying glottic insuffiency, and role of a diagnostic vocal fold augmentation for the patient with secondary muscle tension dysphonia.

Methods

A literature review of PubMed was performed, titles and abstracts were assessed, and articles that most comprehensively addressed our clinical question were selected. We also draw upon the authors’ experience with the management of secondary muscle tension dysphonia. A representative case presentation along with review of classification, diagnosis, work-up and management of muscle tension dysphonia in the setting of glottic insuffiency is presented.

Conclusions

Glottic insuffiency resulting in secondary muscle tension dysphonia is an under-recognised contributor to voice and laryngeal related complaints. When behavioural treatments are unsuccessful, a diagnostic vocal fold injection is a relatively simple method to determine if addressing underling the glottic insufficiency affords symptomatic improvement. If a favourable response is obtained, it is reasonable for both patient and treating surgeon to proceed with a more durable or even permanent augmentation option.
GPU-I-TASSER: a GPU accelerated I-TASSER protein structure prediction tool
Authors: MacCarthy Elijah A , Zhang Chengxin , Zhang Yang , KC Dukka B
Published: December 2021

Motivation

Accurate and efficient predictions of protein structures play an important role in understanding their functions. Iterative Threading Assembly Refinement (I-TASSER) is one of the most successful and widely used protein structure prediction methods in the recent community-wide CASP experiments. Yet, the computational efficiency of I-TASSER is one of the limiting factors that prevent its application for large-scale structure modeling.

Results

We present I-TASSER for Graphics Processing Units (GPU-I-TASSER), a GPU accelerated I-TASSER protein structure prediction tool for fast and accurate protein structure prediction. Our implementation is based on OpenACC parallelization of the replica-exchange Monte Carlo simulations to enhance the speed of I-TASSER by extending its capabilities to the GPU architecture. On a benchmark dataset of 71 protein structures, GPU-I-TASSER achieves on average a 10× speedup with comparable structure prediction accuracy compared to the CPU version of the I-TASSER.

Availability and implementation

The complete source code for GPU-I-TASSER can be downloaded and used without restriction from https://zhanggroup.org/GPU-I-TASSER/.

Supplementary information

Supplementary data are available at Bioinformatics online.
Oocyte quality following in vitro follicle development
Authors: Xu Jing , Zelinski Mary B
Published: December 2021

In vitro follicle development (IVFD) is an adequate model to obtain basic knowledge of folliculogenesis and provides a tool for ovarian toxicity screening. IVFD yielding competent oocytes may also offer an option for fertility and species preservation. To promote follicle growth and oocyte maturation in vitro, various culture systems are utilized for IVFD in rodents, domestic animals, wild animals, nonhuman primates, and humans. Follicle culture conditions have been improved by optimizing gonadotropin levels, regulatory factors, nutrient supplements, oxygen concentration, and culture matrices. This review summarizes quality assessment of oocytes generated from in vitro-developed antral follicles from the preantral stage, including oocyte epigenetic and genetic profile, cytoplasmic and nuclear maturation, preimplantation embryonic development following in vitro fertilization, as well as pregnancy and live offspring after embryo transfer. The limitations of oocyte quality evaluation following IVFD and the gaps in our knowledge of IVFD to support proper oocyte development are also discussed. The information may advance our understanding of the requirements for IVFD, with a goal of producing competent oocytes with genetic integrity to sustain embryonic development resulting in healthy offspring.
In vitro fluorescence assay to measure GDP/GTP exchange of guanine nucleotide exchange factors of Rho family GTPases
Authors: Blaise Alyssa M , Corcoran Ellen E , Wattenberg Eve S , Zhang Yan-Ling , Cottrell Jeffrey R , Koleske Anthony J
Published: December 2021

Guanine nucleotide exchange factors (GEFs) are enzymes that promote the activation of GTPases through GTP loading. Whole exome sequencing has identified rare variants in GEFs that are associated with disease, demonstrating that GEFs play critical roles in human development. However, the consequences of these rare variants can only be understood through measuring their effects on cellular activity. Here, we provide a detailed, user-friendly protocol for purification and fluorescence-based analysis of the two GEF domains within the protein, Trio. This analysis offers a straight-forward, quantitative tool to test the activity of GEF domains on their respective GTPases, as well as utilize high-throughput screening to identify regulators and inhibitors. This protocol can be adapted for characterization of other Rho family GEFs. Such analyses are crucial for the complete understanding of the roles of GEF genetic variants in human development and disease.
Inhibiting mitochondrial fission rescues degeneration in hereditary spastic paraplegia neurons
Authors: Chen Zhenyu , Chai Eric , Mou Yongchao , Roda Ricardo H , Blackstone Craig , Li Xue-Jun
Published: December 2021

Hereditary spastic paraplegias are characterized by lower limb spasticity resulting from degeneration of long corticospinal axons. SPG11 is one of the most common autosomal recessive hereditary spastic paraplegias, and the SPG11 protein spatacsin forms a complex with the SPG15 protein spastizin and heterotetrameric AP5 adaptor protein complex, which includes the SPG48 protein AP5Z1. Using the integration-free episomal method, we established SPG11 patient-specific induced pluripotent stem cells (iPSCs) from patient fibroblasts. We differentiated SPG11 iPSCs, as well as SPG48 iPSCs previously established, into cortical projection neurons and examined protective effects by targeting mitochondrial dynamics using P110, a peptide that selectively inhibits mitochondrial fission GTPase Drp1. P110 treatment mitigates mitochondrial fragmentation, improves mitochondrial motility, and restores mitochondrial health and ATP levels in SPG11 and SPG48 neurons. Neurofilament aggregations are increased in SPG11 and SPG48 axons, and these are also suppressed by P110. Similarly, P110 mitigates neurofilament disruption in both SPG11 and SPG48 knockdown cortical projection neurons, confirming the contribution of hereditary spastic paraplegia gene deficiency to subsequent neurofilament and mitochondrial defects. Strikingly, neurofilament aggregations in SPG11 and SPG48 deficient neurons double stain with ubiquitin and autophagy related proteins, resembling the pathological hallmark observed in SPG11 autopsy brain sections. To confirm the cause-effect relationship between the SPG11 mutations and disease phenotypes, we knocked-in SPG11 disease mutations to human embryonic stem cells (hESCs) and differentiated these stem cells into cortical projection neurons. Reduced ATP levels and accumulated neurofilament aggregations along axons are observed, and both are mitigated by P110. Furthermore, rescue experiment with expression of wild-type SPG11 in cortical projection neurons derived from both SPG11 patient iPSCs and SPG11 disease mutation knock-in hESCs leads to rescue of mitochondrial dysfunction and neurofilament aggregations in these SPG11 neurons. Finally, in SPG11 and SPG48 long-term cultures, increased release of phosphoNF-H, a biomarker for nerve degeneration, is significantly reduced by inhibiting mitochondrial fission pharmacologically using P110 and genetically using Drp1 shRNA. Taken together, our results demonstrate that impaired mitochondrial dynamics underlie both cytoskeletal disorganization and axonal degeneration in SPG11 and SPG48 neurons, highlighting the importance of targeting these pathologies therapeutically.
Propofol anesthesia concentration rather than abrupt behavioral unresponsiveness linearly degrades responses in the rat primary auditory cortex
Authors: Bergman Lottem , Krom Aaron J , Sela Yaniv , Marmelshtein Amit , Hayat Hanna , Regev Noa , Nir Yuval
Published: December 2021

Despite extensive knowledge of its molecular and cellular effects, how anesthesia affects sensory processing remains poorly understood. In particular, it remains unclear whether anesthesia modestly or robustly degrades activity in primary sensory regions, and whether such changes are linked to anesthesia drug concentration versus behavioral unresponsiveness, which are typically confounded. Here, we used slow gradual intravenous propofol anesthesia induction together with auditory stimulation and intermittent assessment of behavioral responsiveness while recording epidural electroencephalogram, and neuronal spiking activity in primary auditory cortex (PAC) of eight rats. We found that all main components of neuronal activity including spontaneous firing rates, onset response magnitudes, onset response latencies, postonset neuronal silence duration, late-locking to 40 Hz click-trains, and offset responses, gradually changed in a dose-dependent manner with increasing anesthesia levels without showing abrupt shifts around loss of righting reflex or other time-points. Thus, the dominant factor affecting PAC responses is the anesthesia drug concentration rather than any sudden, dichotomous behavioral state changes. Our findings explain a wide array of seemingly conflicting results in the literature that, depending on the precise definition of wakefulness (vigilant vs. drowsy) and anesthesia (light vs. deep/surgical), report a spectrum of effects in primary regions ranging from minimal to dramatic differences.
Family Systems and Emotional Functioning in Deaf or Hard-of-Hearing Preschool Children
Authors: Yuen Shannon , Li Boya , Tsou Yung-Ting , Meng Qi , Wang Liyan , Liang Wei , Rieffe Carolien
Published: December 2021

This study examined how deaf or hard-of-hearing (DHH) and typically hearing (TH) children may differ in their family system and emotional functioning and examined the relations between family system and children’s emotional functioning. Parents of 106 DHH and 99 TH children (2–6 years) reported on family cohesion and adaptability, parental emotion communication, and their child’s emotional functioning. The DHH children were rated lower on family cohesion and positive emotion expression than the TH children. Higher levels of family cohesion related to more positive emotion expression in TH children but not in DHH children. For all children, higher levels of family cohesion related to fewer negative emotion expressions and more parental emotion communication related to more negative emotion expression. The results emphasize the importance of sharing leisure activities together and open communication within the family, which can support DHH and TH children’s experience of emotions and their expressions of them.
Clinical applications of cardiac computed tomography: a consensus paper of the European Association of Cardiovascular Imaging—part II
Authors: Pontone Gianluca , Rossi Alexia , Guglielmo Marco , Dweck Marc R , Gaemperli Oliver , Nieman Koen , Pugliese Francesca , Maurovich-Horvat Pal , Gimelli Alessia , Cosyns Bernard , Achenbach Stephan
Published: December 2021

Cardiac computed tomography (CT) was initially developed as a non-invasive diagnostic tool to detect and quantify coronary stenosis. Thanks to the rapid technological development, cardiac CT has become a comprehensive imaging modality which offers anatomical and functional information to guide patient management. This is the second of two complementary documents endorsed by the European Association of Cardiovascular Imaging aiming to give updated indications on the appropriate use of cardiac CT in different clinical scenarios. In this article, emerging CT technologies and biomarkers, such as CT-derived fractional flow reserve, perfusion imaging, and pericoronary adipose tissue attenuation, are described. In addition, the role of cardiac CT in the evaluation of atherosclerotic plaque, cardiomyopathies, structural heart disease, and congenital heart disease is revised.
Association of transcatheter edge-to-edge repair with improved survival in older patients with severe, symptomatic degenerative mitral regurgitation
Authors: Benfari Giovanni , Sorajja Paul , Pedrazzini Giovanni , Taramasso Maurizio , Gavazzoni Mara , Biasco Luigi , Essayagh Benjamin , Grigioni Francesco , Bae Richard , Tribouilloy Christophe , Vanoverschelde Jean-Louis , Michelena Hector , Bapat Vinayak N , Vancraynest David , Klersy Catherine , Curti Moreno , Thapa Prabin , Enriquez-Sarano Maurice
Published: December 2021

Background

Randomized clinical trials demonstrated transcatheter edge-to-edge repair (TEER) efficacy in improving outcome vs. medical management for functional mitral regurgitation, but limited randomized data are available for the treatment of degenerative mitral regurgitation (DMR). We aimed to compare the outcome of older patients treated with TEER vs. unoperated DMR.

Methods and results

Registries including consecutive patients ≥65 years with symptomatic severe DMR treated with TEER (MitraSwiss and Minneapolis Heart Institute registries) or unoperated (MIDA registry) were analysed. Survival was compared overall and after matching for age, sex, EuroSCORE II, and ejection fraction. The study included 1187 patients (872 treated with TEER and 315 unoperated). During 24 ± 17 months of follow-up, 430 patients died, 18 ± 1% at 1 year and 50 ± 2% at 4 years. Patients undergoing TEER had similar age (82 ± 6 vs. 82 ± 7 years) and sex to unoperated patients, but higher surgical risk/comorbidity (EuroSCORE II 3.98 ± 4.28% vs. 2.77 ± 2.46%), more symptoms, and atrial fibrillation (P < 0.0001). Transcatheter edge-to-edge repair was associated with lower mortality accounting for age, sex, EuroSCORE II, New York Heart Association class, atrial fibrillation, and ejection fraction [hazard ratio (HR): 0.47, 95% confidence interval (CI): 0.37–0.58; P < 0.0001]. After propensity matching (247 pairs of patients), TEER consistently showed better survival compared with unoperated patients (49 ± 6% vs. 37 ± 3% at 4 years, P < 0.0001) even in comprehensive multivariable analysis (HR: 0.60, 95% CI: 0.40–0.91; P = 0.03). Procedural failure was infrequent but post-procedural mitral regurgitation, remaining moderate-to-severe in 66 (7.6%) patients, was associated with excess mortality vs. trivial residual regurgitation (30 ± 6% vs. 11 ± 1% at 1 year, P < 0.0001).

Conclusion

Amongst older patients with severe symptomatic DMR at high surgical risk, mitral TEER was associated with higher survival vs. unoperated patients. Successful control of mitral regurgitation was key to survival improvement with mitral TEER, which should be actively considered in patients deemed inoperable.
Management of ventricular tachycardia in patients with ischaemic cardiomyopathy: contemporary armamentarium
Authors: Kahle Ann-Kathrin , Jungen Christiane , Alken Fares-Alexander , Scherschel Katharina , Willems Stephan , Pürerfellner Helmut , Chen Shaojie , Eckardt Lars , Meyer Christian
Published: December 2021

Worldwide, ∼4 million people die from sudden cardiac death every year caused in more than half of the cases by ischaemic cardiomyopathy (ICM). Prevention of sudden cardiac death after myocardial infarction by implantation of a cardioverter-defibrillator (ICD) is the most common, even though not curative, therapy to date. Optimized ICD programming should be strived for in order to decrease the incidence of ICD interventions. Catheter ablation reduces the recurrence of ventricular tachycardias (VTs) and is an important adjunct to sole ICD-based treatment or pharmacological antiarrhythmic therapy in patients with ICM, as conclusively demonstrated by seven randomized controlled trials (RCTs) in the last two decades. However, none of the conducted trials was powered to reveal a survival benefit for ablated patients as compared to controls. Whereas thorough consideration of an early approach is necessary following two recent RCTs (PAUSE-SCD, BERLIN VT), catheter ablation is particularly recommended in patients with recurrent VT after ICD therapy. In this context, novel, pathophysiologically driven ablation strategies referring to deep morphological and functional substrate phenotyping based on high-resolution mapping and three-dimensional visualization of scars appear promising. Emerging concepts like sympathetic cardiac denervation as well as radioablation might expand the therapeutical armamentarium especially in patients with therapy-refractory VT. Randomized controlled trials are warranted and on the way to investigate how these translate into improved patient outcome. This review summarizes therapeutic strategies currently available for the prevention of VT recurrences, the optimal timing of applicability, and highlights future perspectives after a PAUSE in BERLIN.
Visual Difficulty, Race and Ethnicity, and Activity Limitation Trajectories Among Older Adults in the United States: Findings From the National Health and Aging Trends Study
Authors: Ehrlich Joshua R , Hu Mengyao , Zhou Yunshu , Kai Rohan , De Lott Lindsey B
Published: December 2021

Objectives

To characterize the influence of visual difficulty on activity limitation trajectories in older U.S. adults and investigate whether this varied across racial/ethnic groups.

Methods

We used data from 8,077 participants in the nationally representative National Health and Aging Trends Study from 2011 to 2019. Using mixed-effects regression models, we investigated the association of self-reported visual difficulty and race/ethnicity with activity limitation trajectories.

Results

Higher levels of visual difficulty and belonging to a minority racial/ethnic group were associated with greater mobility, self-care, and household activity limitations. Visual difficulty was associated with mobility and self-care activity limitation trajectories, and race/ethnicity was significantly associated with mobility and household activity limitation trajectories. Among those with the highest levels of visual difficulty, non-Hispanic Black participants experienced a faster rate of decline in self-care activities compared to non-Hispanic White participants.

Discussion

Promoting optimal aging for all requires an understanding of the factors that influence disparities in key outcomes. Our study provides evidence from a diverse national sample that visual difficulty appears to disproportionately affect activity limitation trajectories among older adults from minority racial/ethnic groups and particularly among non-Hispanic “Black individuals.” Further research is needed to determine whether interventions to promote healthy vision may positively affect overall activity and independence and ameliorate disparities in late-life activity limitation trajectories.
Quantifying low-frequency acoustic fields in urban environments
Authors: McComas Sarah , Arrowsmith Stephen , Hayward Chris , Stump Brian , McKenna Taylor Mihan H
Published: December 2021

Infrasound data contain contributions from incoherent noise, coherent noise and signals of interest. The design of an infrasound array to target sources of interest requires a quantification of array response, individual sensor response, propagation effects (topography and meteorological conditions), signal spectrum and the noise environment. The Comprehensive Nuclear-Test-Ban Treaty community has spent significant effort in quantifying the acoustic field in rural environments for frequencies up to 7 Hz. Given that the nuclear monitoring and tactical infrasound community have growing interests in monitoring sources in or near populated regions, there is an emergent need to measure and understand acoustic fields in these environments as well. This paper focuses on quantification of the acoustic field in three different urban environments: (1) arrays installed within Dallas, TX, a metropolitan area, (2) an array installed at the rural–suburban interface near San Diego, CA and (3) an array installed in Vicksburg, MS, a small city with multiple major transportation corridors. A minimum of five months of data was recorded and used for each site characterization. The analysis focuses on frequencies from 0.1 to 45 Hz. The quantification of the data from these three sites is accomplished with statistical noise models that capture the total ambient acoustic field, separation of the coherent portion of the field and trend analysis to link temporal and seasonal variations to wind speed and anthropogenic activities. The resulting physical interpretation of the data demonstrates that the total acoustic field in urban regions is overall higher and inversely related to the number of coherent detections observed by an array. Furthermore, this study presents an analysis framework for characterizing additional urban arrays and provides a basis for future array site selection and installation.
Experimental and numerical analysis of laminated carbon fibre-reinforced polymer gears with implicit model for coefficient-of-friction evaluation
Authors: Černe B , Bergant Z , Šturm R , Tavčar J , Zorko D
Published: December 2021

Laminated composites have so far received little attention as a potential material for gear drive applications. In the presented study, the thermomechanical performance of a newly developed type of epoxy impregnated, autoclave-cured carbon fibre-reinforced polymer gear—running in pair with a steel pinion—was analysed, using a combination of experimental and numerical approaches. The employed methods enabled the identification of the composite’s mechanical, thermal, and tribological characteristics, as related to the studied gear pair application. A newly proposed, finite-element-analysis-based iterative procedure enabled an implicit evaluation of the analysed material pair’s coefficient of friction (COF), which is a key parameter in determining the gear pair’s thermomechanical characteristics. For the considered material pair, a value of 0.34 was identified for the coefficient in the quasi-steady region. As the coefficient is strongly correlated with frictional heat generation and significantly affects the surface shear stress, it can consequently have a meaningful influence on the composite’s wear rate. The developed COF identification procedure was validated using a reciprocating cylinder-on-flat tribological test method. The composite gear’s service life was additionally tested at various running loads, resulting in pitch contact pressures ranging between 400 and 540 MPa. Lifetime gear test results showed a markedly superior performance compared to the high-temperature thermoplastic polyether ether ketone, which is typically employed in the most demanding polymer gear applications. Several methods are additionally proposed that could further improve the developed composite gears’ performance.