bluuebunny/crossref_metadata_2025 huggingface dataset:
Silver‐Based Conductive Ink on Paper Electrodes Based on Micro‐Pen Writing for Electroanalytical Applications
Authors: Zhao Chen‐Fei , Wang Jun , Zhang Zhuo‐Qing , Sun Zhao , Maimaitimin Zuliaya
Published: September 2022

Nano‐silver conductive inks have attracted the attention of researchers due to their high electrical conductivity, good chemical stability, and wide applicability. As the mainstream conductive ink, it is mostly used in inkjet printing, but its application is limited due to the high sintering temperature. In this paper, silver nanoparticles were synthesized by reducing silver nitrate with sodium borohydride. Using silver nanoparticles as basic conductive fillers and graphene or copper nanoparticles as auxiliary conductive fillers, silver conductive inks, silver/graphene conductive inks and silver/copper conductive inks suitable for micro‐direct writing printing were prepared. Electrode patterns were printed on photo paper by micro‐pen writing printing. The prepared paper electrode can detect nitrate using electrochemical analysis. The results show that the paper electrodes prepared with the three conductive inks can be used for the analysis of potassium ferricyanide and potassium nitrate. The minimum square resistance of paper electrodes prepared with silver conductive ink is 0.11 Ω/sq. It can be cycled 60 times in electrochemical applications with small standard deviation and high reproducibility and stability. Analysis and detection can also be performed in nitrate concentrations ranging from 60 μM to 1000 μM. This low silver‐containing, green, and low resistivity flexible electrode offers a solution for the simplicity and economy of electronic devices.
Electrophotochemical Metal‐Catalyzed Decarboxylative Coupling of Aliphatic Carboxylic Acids
Authors: Yang Kai , Lu Jiaqing , Li Liubo , Luo Sanzhong , Fu Niankai
Published: September 2022

An electrophotochemical dual metal‐catalyzed protocol for decarboxylative arylation of simple aliphatic carboxylic acids with aryl halides is reported. The relative stabilities of catalytically active metal complexes simultaneously generated at anode and cathode are the key design elements for the success of this convergent paired electrolysis. This new electrophotocatalytic method is mild, robust, and most importantly, capable of accommodating simple primary aliphatic acids including acetic acid – ubiquitous and variegated structural motifs yet remain oddly challenging substrates – directly as native functional groups for decarboxylative C(sp2)−C(sp3) bond formation.
Peri‐Functionalized Tetraazaperylenes: Strong Emitters for Molecular Polaritonics
Authors: Wesp Tobias , Valsalan Parvathi , Kochan Alexander , Hertzog Manuel , Wadepohl Hubert , Zaumseil Jana , Gade Lutz H.
Published: September 2022

The functionalization of the peri position of the bay chlorinated tetraazaperylene was investigated by varying the donor behavior of the substituents to assess the resulting photophysical and electrochemical properties. To accomplish this, electron donating alkyl‐ and arylsulfido substituents, methoxy and methyl groups were selectively introduced into the peri position via a nucleophilic aromatic substitution of the perchlorinated tetraazaperylene. Both the alkylated and benzylated thioethers displayed high fluorescence quantum yields of up to 80 %. Compounds from the latter group were integrated in resonant optical microcavities to achieve strong light‐matter coupling. The formation of exciton‐polaritons was observed by angle‐dependent reflectivity and photoluminescence that could be tuned by variation of the concentration of the fluorophores and of the thickness of the cavity.
A Porous Polyaromatic Solid for Vapor Adsorption of Xylene with High Efficiency, Selectivity, and Reusability
Authors: Sumida Ryuki , Matsumoto Takeshi , Yokoi Toshiyuki , Yoshizawa Michito
Published: September 2022

Development of porous materials capable of capturing volatile organic compounds (VOCs), such as benzene and its derivatives, with high efficiency, selectivity, and reusability is highly demanded. Here we report unusual vapor adsorption behavior toward VOCs by a new porous solid, composed of a polyaromatic capsule bearing a spherical nanocavity with subnano‐sized windows. Without prior crystallization and high‐temperature vacuum drying, the porous polyaromatic solid exhibits the following five features: vapor adsorption of benzene over cyclohexane with 90 % selectivity, high affinity toward o‐xylene over benzene and toluene with >80 % selectivity, ortho‐selective adsorption ability (>50 %) from mixed xylene isomers, tight VOCs storage even under high temperature and vacuum conditions, and at least 5 times reusability for xylene adsorption. The observed adsorption abilities are accomplished at ambient temperature and pressure within 1 h, which has not been demonstrated by organic/inorganic porous materials reported previously.
Auto‐thermal chemical looping combustion of sulphur with Fe2O3 oxygen carriers for sulphuric acid production: Thermodynamics
Authors: Gao Peng , Shen Yue , Zheng Min , Bao Guirong , Wang Hua , Xie Haitao , Wang Lulu
Published: September 2022

Chemical looping is a novel fuel conversion and material separation technology. It can be applied to obtain sulphur through selective oxidation of H2S. Further, chemical looping combustion (CLC) of sulphur can generate SO2 with a high concentration without NOx formation. The high SO2 concentration is adjustable and facilitates large‐scale H2SO4 production. In this study, we examined the thermodynamics of the CLC of sulphur for H2SO4 production, which has not been reported previously. We analyzed the effects of reactor temperature and sulphur to Fe2O3 oxygen carrier (OC) ratios on sulphur allotrope transformations and on the distributions of reaction products. Moreover, the reactors were operated auto‐thermally. Based on this design, we examined the effects of fuel reactor (FR) and air reactor temperatures on the minimum recirculation of the OC, as well as the gas and solid products and heat released from the air reactor. Our results showed that the CLC of sulphur with Fe2O3 OC could occur through an auto‐thermal process. The FR in a sulphur CLC system should be operated over a temperature range of 800–950°C, with an Fe2O3 OC recirculation between 45 and 143 kg/kgS(s). Furthermore, when the FR was operated in the auto‐thermal mode, we achieved 100% SO2 conversion. The findings of this study may be applied to reactor design for large‐scale H2SO4 production through CLC of sulphur.
Reactivity stabilization and capacity study of fabricated alumina and zirconia‐supported CaO‐based sorbents for high‐temperature CO2 capture in a fixed‐bed reactor
Authors: Mohammadi Mahshid , Sedghkerdar Mohammad Hashem , Abbasi Mohsen , Izadbakhsh Ali , Karami Davood
Published: September 2022

Calcium looping process is a promising approach for CO2 capture from the flue gas of fossil fuel power plants and the cement industry. Even though the advantages of calcium‐based sorbents are low cost and high uptake capacity, they suffer from low durability during cycles. Modified sorbents were fabricated by adding alumina and zirconia and the mixture of alumina and zirconia to calcium oxide via the co‐precipitation method. The performance of synthesized sorbents in terms of stability and CO2 capture capacity were evaluated using a fixed bed reactor in various CO2 sorption/desorption cycles. The sorbents were fabricated by a co‐precipitation methodology using 10% binders (alumina and/or silica). X‐ray diffraction (XRD), BET/BJH, and scanning electron microscopy (SEM) were conducted for characterization of synthesized sorbents. CaO‐10% ZrO2 showed the best performance among the fabricated sorbents in terms of stability during 5 cycles and CO2 capacity (14 mmol CO2/g sorbent). The formation of CaZrO3 with a perovskite structure and high‐temperature resistance could be attributed to well performance of zirconia‐supported sorbent. On the other hand, no sign of aluminum zirconate formation was approved in XRD analysis for the fabricated sorbent using mixed binders of zirconia and alumina to enhance its stability during cycles.
Exploring a Tetrahydroquinoline Antimalarial Hit from the Medicines for Malaria Pathogen Box and Identification of its Mode of Resistance as PfeEF2
Authors: Laleu Benoît , Rubiano Kelly , Yeo Tomas , Hallyburton Irene , Anderson Mark , Crespo‐Fernandez Benigno , Gamo Francisco‐Javier , Antonova‐Koch Yevgeniya , Orjuela‐Sanchez Pamela , Wittlin Sergio , Jana Gouranga P. , Maity Bikash C. , Chenu Elodie , Duffy James , Sjö Peter , Waterson David , Winzeler Elizabeth , Guantai Eric , Fidock David A. , Hansson Thomas G.
Published: September 2022

New antimalarial treatments with novel mechanism of action are needed to tackle Plasmodium falciparum infections that are resistant to first‐line therapeutics. Here we report the exploration of MMV692140 (2) from the Pathogen Box, a collection of 400 compounds that was made available by Medicines for Malaria Venture (MMV) in 2015. Compound 2 was profiled in in vitro models of malaria and was found to be active against multiple life‐cycle stages of Plasmodium parasites. The mode of resistance, and putatively its mode of action, was identified as Plasmodium falciparum translation elongation factor 2 (PfeEF2), which is responsible for the GTP‐dependent translocation of the ribosome along mRNA. The compound maintains activity against a series of drug‐resistant parasite strains. The structural motif of the tetrahydroquinoline (2) was explored in a chemistry program with its structure‐activity relationships examined, resulting in the identification of an analog with 30‐fold improvement of antimalarial asexual blood stage potency.
Energy‐efficient computation offloading and resource allocation in delay‐constrained vehicular edge network
Authors: Yang Junchao , Lin Feng , Saini Dinesh Kumar , Zhu Yanyan , Li Yu , Guo Zhiwei
Published: September 2022

Cellular vehicular‐to‐everything (C‐V2X), as a key technology of Internet of Vehicles (IoV), is promised to be enhanced and strengthened to improve road traffic safety and achieve intelligent transportation in 6G era. However, computation‐intensive and latency‐sensitive computation tasks of autonomous driving create a great challenge for the computation and storage limited vehicles. Fortunately, mobile edge computing (MEC) architecture offers a possible solution for the challenge. In this paper, a joint computation offloading and resource allocation algorithm is proposed to solve the computation tasks offloading problem in the scenario of vehicular edge computing network. First, the computation offloading and resource allocation are jointly modeled as a mixed integer nonlinear optimization problem. Aiming at minimizing the total system cost (weighted sum of delay and energy consumption), a particle encoding method and a particle refinement algorithm are proposed based on the compression factor particle swarm optimization, and multilevel penalty function is adopted to deal with the constraints of the objective. Finally, experimental performances validate the effectiveness and feasibility of the proposed algorithm.
Is the (traditional) college still worth it?
Authors: Dennis Marguerite J.
Published: September 2022

Before answering this question, we should ask what education is for and what it means to be educated. Is it to get a well‐paying job after graduation? Is it to leave college with the skills necessary to live a better life?
Electrosurgical knife with the water‐jet function of tip‐type during endoscopic treatment injection
Authors: Ono Satoshi , Kurihara Yasuko , Hirose Fumiya , Aoki Hajime , Maejima Kyohei , Ito Shun , Osumi Shun , Hatori Seika , Fukagawa Kazushi , Hosaka Shosuke , Matsukawa Miho , Kobayashi Ryosuke , Yamazaki Nobuyoshi , Fujishiro Mitsuhiro
Published: September 2022

Objectives

This study aimed to objectively evaluate the water‐jet‐functioned electrosurgical knife injection performances in a desktop experiment.

Methods

Five types of water‐jet‐functioned electrosurgical knives, including two injection styles of sheath‐type (A: DualKnife J, KD‐655L; B: FlushKnife, DK2620‐J‐B20S; C: Splash M‐Knife, DN‐D2718B; D: ISSEN, SN1650‐20) and tip‐type (E: ORISE ProKnife, M00519361) were evaluated. These knives were compared with an injection needle (Control: SuperGrip 25G) as a control. The injection speed under constant pressure and the injection efficiency for each knife against prepared porcine stomach mucosa were evaluated. The additional clear gel injections using an injection needle were observed using an indigo blue‐colored gel to evaluate the difference between the locations of water‐jet holes.

Results

Four types of knives, except for A, showed significantly higher water‐jet speeds (A: 0.79 ± 0.03 g/20 s, B: 2.56 ± 0.05 g/20 s, C: 3.09 ± 0.06 g/20 s, D: 2.86 ± 0.05 g/20 s, and E: 1.79 ± 0.03 g/20 s) compared to that of the control (1.21 ± 0.03 g/20 s). Meanwhile, significantly higher efficacy of injection was found in the tip‐type water‐jet function knife, second to the injection needle (Control: 37.2% ± 35.5%, A: 20.9% ± 20.2%, B: 1.1% ± 2.2%, C: 6.2% ± 12.6%, D: 12.5% ± 15.6%, and E: 33.3% ± 32.2%). An additional injection experiment revealed that the injection with a piercing tip into the gel could achieve sufficient additional injection inside the stacked clear gel.

Conclusions

The tip‐type water‐jet function electrosurgical knife is preferable for effective submucosal injection during endoscopic treatments.
Estimation of Rayleigh flat channel coefficients using deep learning
Authors: Melkote NanjundaShetty Drakshayini , Kounte Manjunath R.
Published: September 2022

Channel estimation is a significant prerequisite in wireless communication, especially where the multipath radio propagation incurs significant fading in a noisy environment. In such a scenario, Rayleigh fading model is traditionally adopted to represent the communication channel. In this article, a new method of getting the Rayleigh flat channel coefficients using deep learning is presented. Here, we presume that the channel state and the corresponding channel coefficients remain constant in a given communication context which depends on the locations of transmitter/receiver, time of the day and the communication environment. When the context changes, the channel state also changes and the corresponding coefficients switch to the respective matching values. Thus the channel coefficients can have several possible realizations or classes. In our scheme, the deep learning network, after training, acts as a classifier to detect the class or the context of the channel state and based on that determines the corresponding channel coefficients. In our proposed method, the percentage reduction in the percentage error is about 26% of that of its nearest competitor when the channel SNR is 10 dB.
Definitions of health and social care standards used internationally: A narrative review
Authors: Kelly Yvonne , O’Rourke Niamh , Flynn Rachel , Hegarty Josephine , O’Connor Laura
Published: September 2022

Setting standards is a quality improvement mechanism and an important means for shaping the provision of health and social care services. Standards comprise statements describing a process or outcome of care. Setting standards is a global practice. It would be useful to have an understanding of the underpinning definitions of standards used internationally. Therefore, the aim of this review was to examine definitions of health and social care standards used internationally and identify similarities and differences. A targeted grey literature search of standard‐setting bodies' websites and related health legislation was conducted to retrieve explicit definitions of standards. Of 15 standard‐setting bodies that were searched, 12 definitions of standards were narratively synthesised. Terms that appeared in two or more of the definitions were extracted. Counts and percentages were calculated for these terms to determine magnitude of use. The commonalities among definitions included ‘quality’ (n = 6, 50%), ‘statements’ (n = 5, 42%), ‘performance’ (n = 5, 42%), and ‘measureable’ (n = 4, 33%). The less commonly used terms were ‘processes’ (n = 3, 25%), ‘set’ (n = 3, 25%), ‘evidence based’ (n = 2, 17%), ‘outcome’ (n = 2, 17%), ‘safe’ (n = 2, 17%), and ‘guidance’ (n = 2, 17%). Explicit definitions of standards were not retrieved from health legislation documents. Standard‐setting bodies develop standards in the context of the health systems in which they are implemented; some are aspirational levels of quality, while others are minimum levels of quality. Researchers, standards developers and policy makers should be cognisant of this when comparing standards between countries.
The magnitude of out‐of‐pocket expenditure for antenatal care in low and middle‐income countries: A systematic review and meta‐analysis
Authors: Gunarathne Sajaan Praveena , Wickramasinghe Nuwan Darshana , Agampodi Thilini Chanchala , Prasanna Indika Ruwan , Agampodi Suneth Buddhika
Published: September 2022

Background

Owing to the lack of compiled global evidence on out‐of‐pocket expenditure (OOPE) for antenatal care (ANC), this systematic review and meta‐analysis estimated the magnitude of OOPE for ANC in low and middle‐income countries (LMICs).

Methods

An electronic search was conducted using 10 databases and a hand search of the eligible studies' reference lists. Studies on OOPE for ANC in LMICs, published in English without time restriction, were included. The comparability of OOPE values was improved using inflation and exchange rate adjustment to the year 2019. Random‐effects meta‐analysis was performed to generate pooled estimates.

Results

Among the 9766 articles retrieved, 32 were selected. Only 13/137 (9.5%) countries reported evidence of OOPE during pregnancy in LMICs. The majority of the studies (n = 2779.4%) were from lower‐middle‐income settings. Ten (31.3%) studies from African region, 21 (65.6%) studies from South‐East‐Asian region, 1 (3.1%) study from region of Americas and none from the other regions were included. The average OOPE for ANC and single ANC visit ranged from United States Dollar (USD) 2.41 to USD 654.32 in LMICs, the lowest in Tanzania and the highest in India. The pooled OOPEs were USD 63.29 (95% confidence interval [CI] = 51.93–74.65) and USD 12.93 (95%CI = 4.54–21.31) for ANC and single ANC visit in LMICs, respectively.

Conclusion

The study revealed that the pooled estimates of OOPE for ANC throughout pregnancy and per visit were high in some countries, with a wide variability observed across countries. There was a lack of evidence on OOPE for ANC from many LMICs, and filling the evidence gap in LMICs is highlighted.
Thermal characteristics of arrays of swirling impinging jets: Effect of Reynolds number, impingement distance, and jet‐to‐jet separation
Authors: Debnath Sudipta , Ahmed Zahir U. , Ikhlaq Muhammad , Khan Tanvir
Published: September 2022

This paper numerically investigates both the inline and staggered arrays of circular multiple swirling air jets that impinge perpendicularly onto a smooth flat surface. The simulations were conducted for various flow and geometric parameters, such as Reynolds number (Re = 11,600, 24,600, and 35,000), jet‐to‐surface distance (H/D = 1, 2, 3, and 4), jet‐to‐jet separation distance (Z/D = 1.5, 3.0, and 4.5) and swirl numbers (S = 0, 0.3, and 0.75), where D is the nozzle diameter. For S = 0.75, a strong recirculation develops due to the vortex breakdown, depends on Z/D, around the axis and near the wall. The extent of the recirculation is larger for the staggered array. Intense heat transfer is anticipated at strong swirl and close impingement cases with the expense of uniformity; whereas a relatively even heat transfer is observed for larger impingements. The increase in jet‐to‐jet separation enhances the overall cooling effect and the staggered configuration of nozzles gives better performance. It appears that both the crossflow and turbulence around the periphery of each jet predominantly govern the heat transfer characteristics. The enhancement of heat transfer occurs for increasing Re, and the overall Nusselt number (Nu) prediction is scaled by Ren, with n dependent on S. Finally a correlation is developed for the average Nusselt number to relate different control parameters.
On the origin of photodynamic activity of hypericin and its iodine‐containing derivatives
Authors: De Simone Bruna Clara , Mazzone Gloria , Toscano Marirosa , Russo Nino
Published: September 2022

The main photophysical properties, useful for establishing whether hypericin in anionic form and some of its derivatives containing heavy atoms such as iodine, can be proposed for their use in photodynamic therapy, were determined using density functional based computations. The results showed that in the anionic form and in the iodinated derivatives, the absorption wavelength undergoes a bathochromic shift, the singlet‐triplet energy gap assumes values ​that allow to excite the oxygen molecule from its ground to the excited singlet state, and that the spin–orbit couplings between singlet and triplet states significantly increase.
Environmental temperature predicts resting metabolic rates in tropidurinae lizards
Authors: Giacometti Danilo , Bars‐Closel Melissa , Kohlsdorf Tiana , de Carvalho José Eduardo , Cury de Barros Fábio
Published: September 2022

Interspecific variation in metabolic rates may be associated with climate, habitat structure, and resource availability. Despite a strong link between ecology and physiology, there is a dearth in the understanding of how the costs of body maintenance change during ecological transitions. We focused on an ecologically diverse group of neotropical lizards (Tropidurinae) to investigate whether and how resting metabolic rate (RMR) evolved under divergent micro‐ and macrohabitat conditions. Using a phylogenetic framework, we tested whether species from hot and dry habitats had lower RMRs in relation to those from cooler and mesic habitats, and investigated whether microhabitat usage had an effect over body mass‐adjusted RMRs. Our results suggest that RMRs are not phylogenetically structured in Tropidurinae. We found no correlation between metabolism, precipitation, and microhabitat usage. Species from warmer habitats had lower RMR compared to those from cooler habitats, supporting a mechanism of negative compensation in metabolic responses to temperature. Ectotherms from warmer habitats can limit energetic demand and expenditure through reduced RMR, whereas those from cooler habitats may sustain activity despite thermal constraints via increased RMR. Our work highlights the role of temperature in shaping metabolic responses in lizards, giving additional support to the notion that physiology and ecological contexts are intertwined.
The distinct problems of physical inconsistency and of multivariate bias involved in the statistical adjustment of climate simulations
Authors: Alavoine Mégane , Grenier Patrick
Published: September 2022

Bias adjustment of numerical climate model simulations involves several arguments wherein the notion of physical inconsistency is referred to, either for rejecting the legitimacy of bias adjustment in general or for justifying the necessity of sophisticated multivariate techniques. However, this notion is often mishandled, in part because the literature generally proceeds without defining it. In this context, the central objective of this study is to clarify and illustrate the distinction between physical inconsistency and multivariate bias, by investigating the effect of bias adjustment on two different kinds of intervariable relationships, namely a physical constraint expected to hold at every step of a time series and statistical properties that emerge with potential bias over a climatic timescale. To this end, 18 alternative bias adjustment techniques are applied on 10 climate simulations at 12 sites over North America. Adjusted variables are temperature, pressure, relative humidity and specific humidity, linked by a thermodynamic constraint. The analysis suggests on the one hand that a clear instance of potential physical inconsistency can be avoided with either a univariate or a multivariate technique, if and only if the bias adjustment strategy explicitly considers the physical constraint to be preserved. On the other hand, it also suggests that sophisticated multivariate techniques alone are not complete adjustment strategies in presence of a physical constraint, as they cannot replace its explicit consideration. By involving common bias adjustment procedures with likely effects on diverse basic statistical properties, this study may also help guide climate information users in the determination of adequate bias adjustment strategies for their research purposes.
A perpetual motion machine: The preserved digital scholarly record
Authors: Cramer Tom , German Chip , Jefferies Neil , Wise Alicia
Published: September 2022

Key points

Digital preservation will never be a solved problem: it needs constant reinvention, and is going to become harder over time.

Scholarship is changing and this is affecting what needs to be preserved and what preservation means to the future of knowledge discovery.

The diversification of outputs means that knowledge exists in a network of contextual metadata, data, software, standards and publications—requiring multilateral management of this complex knowledge graph.

Preservation demands new skills, technologies and resources from librarians, publishers, funders and institutions—and more joined‐up thinking about archiving.
Progression of Clinical and Eye Movement Markers in Preataxic Carriers of Machado‐Joseph Disease
Authors: de Oliveira Camila Maria , Leotti Vanessa Bielefeldt , Cappelli Amanda Henz , Rocha Anastacia Guimarães , Ecco Gabriela , Bolzan Gabriela , Kersting Nathalia , Saraiva‐Pereira Maria‐Luiza , Jardim Laura Bannach
Published: September 2022

Background

Little is known about preclinical stages of Machado‐Joseph disease, a polyglutamine disorder characterized by progressive adult‐onset ataxia.

Objective

We aimed to describe the longitudinal progression of clinical and oculomotor variables in the preataxic phase of disease.

Methods

Carriers and noncarriers were assessed at three visits. Preataxic carriers (Scale for Assessment and Rating of Ataxia score < 3) expected to start ataxia in ≤4 years were considered near onset (PAN). Progressions of ataxic and preataxic carriers, considering status at the end of the study, were described according to the start (or its prediction) of gait ataxia (TimeToAfterOnset) and according to the study time.

Results

A total of 35 ataxics, 38 preataxics, and 22 noncarriers were included. The “TimeToAfterOnset” timeline showed that Neurological Examination Scale for Spinocerebellar Ataxias (NESSCA; effect size, 0.09), Inventory of Non‐Ataxia Symptoms (INAS0.07), and the vestibulo‐ocular reflex gain (0.12) progressed in preataxic carriers, and that most slopes accelerate in PAN, turning similar to those of ataxics. In the study time, NESSCA (1.36) and vertical pursuit gain (1.17) significantly worsened in PAN, and 6 of 11 PANs converted to ataxia. For a clinical trial with 80% power and 2‐year duration, 57 PANs are needed in each study arm to detect a 50% reduction in the conversion rate.

Conclusions

NESSCA, INAS, vestibulo‐ocular reflex, and vertical pursuit gains significantly worsened in the preataxic phase. The “TimeToAfterOnset” timeline unveiled that slopes of most variables are small in preataxics but increase and reach the ataxic slopes from 4 years before the onset of ataxia. For future trials in preataxic carriers, we recommend recruiting PANs and using the conversion rate as the primary outcome. © 2022 International Parkinson and Movement Disorder Society.
Stability of the wave equation with localized Kelvin–Voigt damping and dynamic Wentzell boundary conditions with delay
Authors: Dahmani Abdelhakim , Khemmoudj Ammar
Published: September 2022

In a bounded domain, we consider the wave equation with localized Kelvin–Voigt damping and dynamic boundary conditions of Wentzell type with delay. First of all, using semigroup theory, we prove the existence and uniqueness of a solution in a suitable energy space. Secondly, via Arendt–Batty's criteria, we prove the strong stability under some suitable conditions between the interior damping and the boundary dynamic. Finally, assuming some regularity on the damping coefficient, we show that the exponential stability holds by virtue of the frequency domain approach due to Huang and Prüss, combined with a perturbation argument.
SuperMAP: Deep ultrafast MR relaxometry with joint spatiotemporal undersampling
Authors: Li Hongyu , Yang Mingrui , Kim Jee Hun , Zhang Chaoyi , Liu Ruiying , Huang Peizhou , Liang Dong , Zhang Xiaoliang , Li Xiaojuan , Ying Leslie
Published: September 2022

Purpose

To develop an ultrafast and robust MR parameter mapping network using deep learning.

Theory and Methods

We design a deep learning framework called SuperMAP that directly converts a series of undersampled (both in k‐space and parameter‐space) parameter‐weighted images into several quantitative maps, bypassing the conventional exponential fitting procedure. We also present a novel technique to simultaneously reconstruct T1rho and T2 relaxation maps within a single scan. Full data were acquired and retrospectively undersampled for training and testing using traditional and state‐of‐the‐art techniques for comparison. Prospective data were also collected to evaluate the trained network. The performance of all methods is evaluated using the parameter qualification errors and other metrics in the segmented regions of interest.

Results

SuperMAP achieved accurate T1rho and T2 mapping with high acceleration factors (R = 24 and R = 32). It exploited both spatial and temporal information and yielded low error (normalized mean square error of 2.7% at R = 24 and 2.8% at R = 32) and high resemblance (structural similarity of 97% at R = 24 and 96% at R = 32) to the gold standard. The network trained with retrospectively undersampled data also works well for the prospective data (with a slightly lower acceleration factor). SuperMAP is also superior to conventional methods.

Conclusion

Our results demonstrate the feasibility of generating superfast MR parameter maps through very few undersampled parameter‐weighted images. SuperMAP can simultaneously generate T1rho and T2 relaxation maps in a short scan time.
Test–retest reproducibility of human brain multi‐slice1H FID‐MRSIdata at 9.4T after optimization of lipid regularization, macromolecular model, and spline baseline stiffness
Authors: Ziegs Theresia , Wright Andrew Martin , Henning Anke
Published: September 2022

Purpose

This study analyzes the effects of retrospective lipid suppression, a simulated macromolecular prior knowledge and different spline baseline stiffness values on 9.4T multi‐slice proton FID‐MRSI data spanning the whole cerebrum of human brain and the reproducibility of respective metabolite ratio to total creatine (/tCr) maps for 10 brain metabolites.

Methods

Measurements were performed twice on 5 volunteers using a short TR and TE FID MRSI 2D sequence at 9.4T. The effects of retrospective lipid L2‐regularization, macromolecular spectrum and different LCModel baseline flexibilities on SNR, FWHM, fitting residual, Cramér‐Rao lower bound, and metabolite ratio maps were investigated. Intra‐subject, inter‐session coefficient of variation and the test–retest reproducibility of the mean metabolite ratios (/tCr) of each slice was calculated.

Results

Transversal, sagittal, and coronal slices of many metabolite ratio maps correspond to the anatomically expected concentration relations in gray and white matter for the majority of the cerebrum when using a flexible baseline in LCModel fit. Results from the second measurements of the same subjects show that slice positioning and data quality correlate significantly to the first measurement. L2‐regularization provided effective suppression of lipid‐artifacts, but should be avoided if no artifacts are detected.

Conclusion

Reproducible concentration ratio maps (/tCr) for 4 metabolites (total choline, N‐acetylaspartate, glutamate, and myoinositol) spanning the majority of the cerebrum and 6 metabolites (N‐acetylaspartylglutamate, γ‐aminobutyric acid, glutathione, taurine, glutamine, and aspartate) covering 32 mm in the upper part of the brain were acquired at 9.4T using multi‐slice FID MRSI with retrospective lipid suppression, a macromolecular spectrum and a flexible LCModel baseline.
MR multitasking‐based dynamic imaging for cerebrovascular evaluation (MT‐DICE): Simultaneous quantification of permeability and leakage‐insensitive perfusion by dynamic T1/T2* mapping
Authors: Hu Zhehao , Christodoulou Anthony G. , Wang Nan , Xie Yibin , Shiroishi Mark S. , Yang Wensha , Zada Gabriel , Chow Frances E. , Margol Ashley S. , Tamrazi Benita , Chang Eric L. , Li Debiao , Fan Zhaoyang
Published: September 2022

Purpose

To develop an MR multitasking‐based dynamic imaging for cerebrovascular evaluation (MT‐DICE) technique for simultaneous quantification of permeability and leakage‐insensitive perfusion with a single‐dose contrast injection.

Methods

MT‐DICE builds on a saturation‐recovery prepared multi‐echo fast low‐angle shot sequence. The k‐space is randomly sampled for 7.6 min, with single‐dose contrast agent injected 1.5 min into the scan. MR multitasking is used to model the data into six dimensions, including three spatial dimensions for whole‐brain coverage, a saturation‐recovery time dimension, and a TE dimension for dynamic and quantification, respectively, and a contrast dynamics dimension for capturing contrast kinetics. The derived pixel‐wise time series are converted into contrast concentration‐time curves for calculation of kinetic metrics. The technique was assessed for its agreement with reference methods in and measurements in eight healthy subjects and, in three of them, inter‐session repeatability of permeability and leakage‐insensitive perfusion parameters. Its feasibility was also demonstrated in four patients with brain tumors.

Results

MT‐DICE values of normal gray matter and white matter were in excellent agreement with reference values (intraclass correlation coefficients = 0.860/0.962 for gray matter and 0.925/0.975 for white matter ). Both permeability and perfusion parameters demonstrated good to excellent intersession agreement with the lowest intraclass correlation coefficients at 0.694. Contrast kinetic parameters in all healthy subjects and patients were within the literature range.

Conclusion

Based on dynamic mapping, MT‐DICE allows for simultaneous quantification of permeability and leakage‐insensitive perfusion metrics with a single‐dose contrast injection.
The future of MRI in radiation therapy: Challenges and opportunities for the MR community
Authors: Goodburn Rosie J. , Philippens Marielle E. P. , Lefebvre Thierry L. , Khalifa Aly , Bruijnen Tom , Freedman Joshua N. , Waddington David E. J. , Younus Eyesha , Aliotta Eric , Meliadò Gabriele , Stanescu Teo , Bano Wajiha , Fatemi‐Ardekani Ali , Wetscherek Andreas , Oelfke Uwe , van den Berg Nico , Mason Ralph P. , van Houdt Petra J. , Balter James M. , Gurney‐Champion Oliver J.
Published: September 2022

Radiation therapy is a major component of cancer treatment pathways worldwide. The main aim of this treatment is to achieve tumor control through the delivery of ionizing radiation while preserving healthy tissues for minimal radiation toxicity. Because radiation therapy relies on accurate localization of the target and surrounding tissues, imaging plays a crucial role throughout the treatment chain. In the treatment planning phase, radiological images are essential for defining target volumes and organs‐at‐risk, as well as providing elemental composition (e.g., electron density) information for radiation dose calculations. At treatment, onboard imaging informs patient setup and could be used to guide radiation dose placement for sites affected by motion. Imaging is also an important tool for treatment response assessment and treatment plan adaptation. MRI, with its excellent soft tissue contrast and capacity to probe functional tissue properties, holds great untapped potential for transforming treatment paradigms in radiation therapy. The MR in Radiation Therapy ISMRM Study Group was established to provide a forum within the MR community to discuss the unmet needs and fuel opportunities for further advancement of MRI for radiation therapy applications. During the summer of 2021, the study group organized its first virtual workshop, attended by a diverse international group of clinicians, scientists, and clinical physicists, to explore our predictions for the future of MRI in radiation therapy for the next 25 years. This article reviews the main findings from the event and considers the opportunities and challenges of reaching our vision for the future in this expanding field.
Calibration of concomitant field offsets using phase contrast MRI for asymmetric gradient coils
Authors: Abad Nastaren , Lee Seung‐Kyun , Ajala Afis , In Myung‐Ho , Frigo Louis M. , Bhushan Chitresh , Morris H. Douglas , Hua Yihe , Ho Vincent B. , Bernstein Matt A. , Foo Thomas K. F.
Published: September 2022

Purpose

Asymmetric gradient coils introduce zeroth‐ and first‐order concomitant field terms, in addition to higher‐order terms common to both asymmetric and symmetric gradients. Salient to compensation strategies is the accurate calibration of the concomitant field spatial offset parameters for asymmetric coils. A method that allows for one‐time calibration of the offset parameters is described.

Theory and Methods

A modified phase contrast pulse sequence with single‐sided bipolar flow encoding is proposed to calibrate the offsets for asymmetric, transverse gradient coils. By fitting the measured phase offsets to different gradient amplitudes, the spatial offsets were calculated by fitting the phase variation. This was used for calibrating real‐time pre‐emphasis compensation of the zeroth‐ and first‐order concomitant fields.

Results

Image quality improvement with the proposed corrections was demonstrated in phantom and healthy volunteers with non‐Cartesian and Cartesian trajectory acquisitions. Concomitant field compensation using the calibrated offsets resulted in a residual phase error <3% at the highest gradient amplitude and demonstrated substantial reduction of image blur and slice position/selection artifacts.

Conclusions

The proposed implementation provides an accurate method for calibrating spatial offsets that can be used for real‐time concomitant field compensation of zeroth and first‐order terms, substantially reducing artifacts without retrospective correction or sequence specific waveform modifications.
Five questions with: Mandy Pennington of Wilkes University
Authors: Talarico Donna
Published: September 2022

Every now and then, the Recruiting and Retaining Adult Learners marketing column will profile a communications professional (or two) via a “five questions with” feature. Sometimes the questions will vary from column to column based on current news and trends.
Got funds? Best practices for successful grant applications
Authors: Sutton Halley
Published: September 2022

LAS VEGAS — “I spent about 16 years at Syracuse University, in their emergency communications department. In [this] my former job, ‘no’ was never an option. I had to find a solution [to whatever problem we faced]. Grant funding is similar,” Shannon Day, Grants Development Consultant, Grants Office, LLC, said.
Is the (traditional) college worth it?
Authors: Dennis Marguerite J.
Published: September 2022

Before answering this question, we should ask what is education for and what does it mean to be educated? Is it to get a well‐paying job after graduation? Is it to leave college with the skills necessary to live a better life?
Answer every question with “yes,” encourage professional development
Authors: Hope Joan
Published: September 2022

“Answer every question with ‘yes.’” Jonathan T. Reece, M.Ed., University Registrar at the University of North Carolina at Charlotte, credits that philosophy for his professional success, and it's the advice he gives his staff members and others for growing their careers.
Graphene oxide/epoxy composites with enhanced fracture toughness for liquid hydrogen storage
Authors: Chen Qiang , Sun Tao , Fan Hongyu , Yan Jia , Wu Zhanjun
Published: September 2022

Graphene oxide (GO)/epoxy composites cured by aliphatic dibasic acids have been prepared. The influences of structure of aliphatic dibasic acid and loading of GO on curing process and mechanical properties of epoxy composites were studied. The results show that the reaction activities, gel time of corresponding epoxy‐acid system and tensile strength of the formed epoxy resins decrease with the increase of the chain length of aliphatic dibasic acids. Both fracture toughness (>1.96 MPa⋅m1/2) and elongations at break (>6%) increase with the increase of the chain length of aliphatic dibasic acids. The introduction of GO is helpful to increase the mechanical properties and the gas transmission coefficient of GO/epoxy composites. A maximum of tensile strength and elongations at break were obtained when the loading of GO is 0.6 wt%. The gas transmission coefficient of GO/epoxy composite increases with the increase of GO loading. The excellent mechanical properties and gas leakage resistance coefficient of the formed epoxy composites provides potential application in many fields where conventional brittle epoxy resins are inapplicable.
Percutaneous ablation of malignant and locally aggressive solid tumors in pediatric patients
Authors: Hawari Mohamad El , Moussa Amgad , Erinjeri Joseph P. , Ziv Etay , Maybody Majid , Santos Martin Ernesto G. , Solomon Stephen B. , Gonzalez‐Aguirre Adrian J.
Published: September 2022

Image‐guided percutaneous ablation is an accepted treatment modality for common adult cancers. Unfortunately, its use in patients younger than 18 years is rare. This retrospective review presents our series of pediatric patients treated with ablation at our institution. From January 2002 to December 2021, a total of 14 patients (17 lesions) younger than 18 years were treated with percutaneous image‐guided ablation. Estimated overall survival at 5 years was 58%; median survival of this group was not reached. Estimated local tumor progression‐free survival at 5 years was 62%. One major complication was recorded.
Social rather than physical crowding reduces the required interpersonal distance in virtual environments
Authors: Han Ming , Wang Xue‐Min , Kuai Shu‐Guang
Published: September 2022

Interpersonal distance plays an important role in human social interaction. With the increasing usage of virtual reality in social interaction, people's interpersonal distance in virtual space attracts great attention. It remains unclear whether and to what extent human‐required interpersonal distance is altered by crowded virtual scenes. In this study, we manipulated crowd density in virtual environments and used the classical stop‐distance paradigm to measure required interpersonal distances at different crowd densities. We found that people's required interpersonal distance decreased with increased social crowdedness but not with physical crowdedness. Moreover, the decrease of two types of interpersonal distance was associated with the globally averaged crowd density rather than local crowd density. The reduction is not due to the imitation of other virtual humans in the crowd. Moreover, we developed a model to describe the quantitative relationships between the crowdedness of the environment and the required interpersonal distance. Our finding provides insights into designing user‐friendly virtual humans in metaverse virtual worlds.
Temporal reproduction: A paradigm indicating a 3‐s time window
Authors: Mu Nan , Zhang Dongxue , Zhao Chen
Published: September 2022

The experimental paradigm of temporal reproduction has provided unique insights into the temporal machinery of cognitive processes. Both behavioral observations and electrophysiological methods with this paradigm indicate a time window of some 3 s.
Modified hypoxic challenge testing in children needing nocturnal ventilation: An observational study
Authors: Riley Mollie , Brotherston Stephanie , Kelly Paula , Samuels Martin , Pike Katharine C.
Published: September 2022

Background

Guidelines for air passengers with respiratory disease focus on primary lung pathology. Little evidence exists to guide professionals advising children needing ventilatory support because of neuromuscular or central hypoventilation conditions; these children might risk hypoxia and hypercapnia if unable to mount an adequate hyperventilation response.

Objective

This study assessed the response to low ambient oxygen using a modified hypoxic challenge test. In addition to measuring pulse oximetry and response to supplementary oxygen, we also measured transcutaneous carbon dioxide and response to ventilatory support.

Methods

Twenty children on nocturnal ventilatory support aged 1.6−18 years were recruited in a pragmatic sample from outpatient clinics; 10 with neuromuscular weakness and 10 with central hypoventilation. Participants underwent a two‐stage, modified hypoxic challenge test; a conventional stage, where oxygen alone was titrated according to SpO2, and a new stage, where participants used their routine ventilatory support with oxygen titrated if needed. Participants were interviewed to understand their experiences of testing and of air travel.

Results

Thirteen participants needed supplemental oxygen during the conventional stage, but only two did when using ventilatory support. Transcutaneous carbon dioxide remained within normal range for all participants, on or off ventilatory support. Whilst some participants found testing challenging, participants generally reported both testing and air travel to be valuable.

Conclusions

Evaluating response to patients' usual ventilation through “fitness‐to‐fly” assessment aids decision making when considering whether children who receive nocturnal ventilation can travel by air, since for some using a ventilator reduces or avoids the need for supplemental oxygen.
Longitudinal assessment of maternal depression and early childhood asthma and wheeze: Effect modification by child sex
Authors: Alcala Cecilia S. , Orozco Scott Paloma , Tamayo‐Ortiz Marcela , Hernández Chávez Maria del Carmen , Schnaas Lourdes , Carroll Kecia N. , Niedzwiecki Megan M. , Wright Robert O. , Téllez‐Rojo Martha Maria , Wright Rosalind J. , Hsu Hsiao‐Hsien Leon , Rosa Maria José
Published: September 2022

Background

Studies report associations between maternal mental health and adverse respiratory outcomes in children; however, the impact of timing and duration of maternal distress remains understudied. We sought to longitudinally examine associations between maternal depression and childhood asthma and wheeze, and explore sex differences.

Methods

Maternal depression (n = 601) was assessed using the Edinburgh Depression Scale questionnaire, dichotomized at a clinically relevant cutoff (>12) (a) during pregnancy, (b) postpartum, and (c) postpartum and subsequent time points postnatally (recurrent depression). Report of wheeze in the past 12 months (current wheeze) and asthma were obtained using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire at 48 and 72 months. Associations were analyzed using a modified Poisson regression adjusted for covariates, and in interaction models.

Results

Both postpartum and recurrent depression were associated with higher risk of current wheeze (relative risk [RR]: 1.87, 95% confidence interval [CI]: 1.21, 2.90; RR: 2.41, 95% CI: 1.53, 3.79) and asthma at 48 months (RR: 2.42, 95% CI: 1.01, 5.84; RR: 2.45, 95% CI: 1.02, 5.84). In interaction analyses, associations were stronger in females. Recurrent depression was associated with a higher risk of current wheeze at 48 months in females (RR: 4.34, 95% CI: 2.02, 9.32) when compared to males (RR: 1.89, 95% CI: 1.05, 3.39).

Conclusions

Postpartum and recurrent depression were associated with a higher risk of wheeze and asthma in children. Understanding the temporal‐ and sex‐specific effects of maternal depression may better inform prevention strategies.