bluuebunny/crossref_metadata_2025 huggingface dataset:
Modulation transfer function of digitally reconstructed radiographs using helical computed tomography
Authors: Rathee S. , Fallone B. G. , Robinson D.
Published: July 2002

We have measured the modulation transfer function (MTF), at a distance from CT isocenter, in digitally reconstructed radiographs (DRR) using a bar pattern phantom for axial and helical data acquisitions. Spatial resolution in DRR increases for thinner slice thicknesses (43% at 1.6 lp/cm for 2 mm versus 16% for 5 mm). For the three slice thicknesses studied, the axial scanning mode provided better spatial resolution in DRR than helical scans performed at pitches ⩾1.5 (41% at 1.6 lp/cm for axial, 3 mm slice versus 18% for pitch=2), but is similar to helical scans with pitch of 1. The reconstruction of overlapping slices from helical acquisitions of pitch=1.5 results in spatial resolution of the DRR that is similar to that resulting from axial scans with contiguous reconstruction, but also results in the fine streaks known as “zebra” artifacts in the DRR.
Method for determining photonuclear production of radioisotopes using high‐energy electron beams
Authors: Weeks K. J.
Published: July 2002

Linear accelerators can produce electrons at high power and energy. These electrons can be targeted at materials to produce radionuclides. Monte Carlo simulation is used to follow the path of the linac electrons (15–35 MeV) through materials. The production of photons and their passage through the material is modeled. The method of using this Monte Carlo information to calculate activation in the materials is presented. It is found that kilowatt power levels can produce mCi amounts of radioactivity in minutes. This work permits systematic evaluation of the potential for designing linear accelerators for in‐house production of radionuclides.
Measured water transmission curves and calculated zero field size tumor maximum ratios for 4, 6, and 15 MV x‐rays
Authors: Lee Nina E. , Chen Di , Waggener Robert G. , Blough Melissa M.
Published: July 2002

A multihole diverging Cerrobend plug for megavoltage energies was used to measure water transmission values at different locations in a field at 100 cm source‐to‐axis distance (SAD) for 4, 6, and 15 MV therapy photon beams. The transmission curves in water were measured at 25 locations across the field, and each location was separated by 5 cm at the isocenter. Each transmission value was made using a 0.3175 cm diameter (0.079 cm2 area) hole of 20 cm length at the central axis (CAX). The small field measured transmission curve in water was used to derive the zero field size tumor maximum ratio (TMR) and the primary photon exposure spectrum as a function of energy at depth. The exposure spectrum was used to find an effective photon energy and linear attenuation coefficient at depth and at different locations in the field. These values were found to vary with location in the field.
Isotope choice and the effect of edema on prostate brachytherapy dosimetry
Authors: Butler Wayne M. , Merrick Gregory S. , Dorsey Anthony T. , Lief Jonathan H.
Published: July 2002

In prostate brachytherapy, post implant dosimetry quality parameters may be strongly affected by edema brought on by the trauma of the implant procedure since the amount of edema and the time course of its resolution are highly variable from patient to patient. Edema was simulated from preplans on three prostates which had ultrasound prostate volumes of 18.7, 40.7 and 60.2 cm3 expanded to planning volumes of 32.9, 60.0 and 87.8 cm3, respectively. The preplans were designed so that identical seed distributions for a given prostate gave virtually identical target dose coverage of 99.7±0.3% of the planning volume when using either or Simulated CT edema volume expansions of 0%, 10%, 20% and 30% were imposed anisotropically in accordance with clinical observations so that the expansion in the superior–inferior direction was twice that of the transverse dimensions. Dose‐volume histograms (DVHs) were analyzed for each prostate as a function of isotope and degree of edema. The implants were more greatly affected by fixed amounts of edema than implants, and the slopes of the DVH curves indicate less homogeneity from implants. The DVHs were then weighted according to the portion of the isotope decay curve occupied by each edema step for half‐lives of edema resolution of 5, 10 and 20 days which are within the range of clinically observed resolution times. The weighted DVHs were summed to give a net DVH corresponding to the overall dynamic effect of edema. A greater fraction of the defined prostate volume received doses in the range of likely therapeutic significance, from 75% to 125% of the prescribed minimal peripheral dose (mPD), from implants than from implants. These differences in dosimetric quality arise from two differences in the physical properties of the isotopes: more rapid attenuation of photons with distance creates cool spots in an edematous prostate, and the shorter half‐life of causes a greater fraction of the isotope decay to consist of the prostate in an edematous state. An increase in seed strength by about 10% beyond that required to achieve equal coverage with an identical seed distribution using should minimize the differences brought on by edema.
Frequency representation in the emu basilar papilla
Authors: Köppl Christine , Manley Geoffrey A.
Published: July 2002

The frequency representation on the basilar papilla of the emu was investigated by recording from single auditory afferents and labeling them iontophoretically with horseradish peroxidase. Successfully labeled fibers covered a range of characteristic frequencies from 0.05 to 3.3 kHz, which corresponded to nearly 90% of the total papillar length. The termination sites of labeled fibers within the basilar papilla correlated with their characteristic frequency, the lowest frequencies being represented apically, the highest basally. The best mathematical description of the frequency distribution was given by an exponential regression, with a uniform mapping constant of 0.8 mm/octave. This function deviates from the more commonly observed pattern of increasing space constant towards higher frequencies. Most labeled fibers innervated only one hair cell; those contacting 4 or more hair cells were all of low characteristic frequency (⩽0.11 kHz). All labeled fibers terminated within the neural 56% of the basilar papilla’s width. This innervation pattern is consistent with that observed in other bird species. There was no conclusive evidence for a change of sensitivity and/or frequency selectivity with innervational position across the papilla’s width.
Harmonic fusion and pitch shifts of mistuned partials
Authors: de Cheveigné Alain
Published: July 2002

A model is proposed to explain pitch shifts of components mistuned from a harmonic series [W. M. Hartmann and S. L. Doty, “On the pitches of the components of a complex tone,” J. Acoust. Soc. Am. 99, 567–578 (1996)]. An internal random variable depends on the frequency of the partial and determines both its pitch and the probability that it will fuse within the complex. The model accounts for the sign of the pitch shifts (positive for positive mistunings, negative for negative mistunings), the fact that they saturate and become smaller for large mistunings, and, given reasonable assumptions on the underlying distributions, their overall shape and magnitude. No assumptions are required concerning the pitch extraction mechanism (place, time, etc.) other than that a common source of variability affects cues to both pitch and harmonic fusion.
Ultrasonic relaxation associated with proton transfer reaction in aqueous solutions of heterocyclic amines
Authors: Nishikawa Sadakatsu , Satoh Masumi
Published: July 2002

Ultrasonic absorption coefficients were measured in aqueous solutions of imidazole and pyrazole by pulse and resonance methods in the frequency range from 3 to 220 MHz at 25 °C. Excess absorption was observed in both solutions. From the concentration dependence of the ultrasonic relaxation parameters associated with a single relaxational process in the solution of imidazole, the cause of the relaxation was proven to be due to a proton transfer reaction and the rate and equilibrium constants were determined for the process. The association rate constant for the ions was reasonable as a diffusion controlled reaction, although it is considerably greater than those in other amine solutions. A standard volume change of the reaction was also determined from the reactant concentration dependence of a maximum absorption per wavelength. The diffusion controlled rate constant for imidazole was considered in relation to the unique molecular structure of imidazole and the effect of the solute on water structure. In the solution of pyrazole, it was not possible to determine the relaxational parameters because the relaxation frequency was located quite below the measurement frequency range.
Estimation of equivalent circuit parameters for piezoelectric transducer using least-squares method
Authors: Jun Byung-Doo , Sung Koeng-Mo
Published: July 2002

In general, the resonance method has been used for estimating the equivalent circuit parameters for the underwater piezoelectric transducer. Sometimes, however, it is difficult to estimate the equivalent circuit parameters when the measured electrical impedances have an imaginary part at resonant and antiresonant frequency. In this paper, to estimate the equivalent circuit parameters of the piezoelectric transducers, equivalent circuit equation is modified and the least-squares method is applied. Equivalent circuit equation is composed of real and imaginary equations, respectively. With these equations, matrix form Yule–Walker equations are formulated. The least-squares method is applied with measured electrical impedance data over the effective frequency band to solve these equations. The procedure is as follows: First, four variables which are functions of five equivalent circuit parameters (R, L, C) are obtained by the least-squares method. Then, initial equivalent circuit parameters can be extracted by solving four equations which contain five parameters, one of which is assumed. Finally, by iteration and update, all the equivalent circuit parameters can be estimated with considerably small error. The impedance characteristics of the piezoelectric transducer with estimated parameters are in good agreement with measured ones.
Laser-modulated phase-stepping digital shearography for quantitative full-field imaging of ultrasonic waves
Authors: Bard Benjamin A. , Gordon Grant A. , Wu Shudong
Published: July 2002

Measurement of surface displacements due to ultrasonic wave propagation in elastic solids has traditionally been studied using single-point measurement techniques such as ultrasonic transducers or interferometers. Full-field methods, excluding scanning techniques, are uncommon; examples include holographic interferometry and Schlieren imaging. In many cases, these techniques have been used to yield qualitative results due to inherent difficulties in processing the data. Laser-modulated phase-stepping digital shearography is a full-field, common-path, interferometric method which can be used to quickly visualize ultrasonic wave fields. A shearography system will be described that provides not only whole-field images of ultrasonic waves, but quantitative displacement data within these fields. Images are shown of propagating plate and bar waves, and mathematics relating the calculated optical phase to the ultrasonic wave parameters are presented.
Caustic diffraction fields in a downward refracting atmosphere
Authors: Salomons Erik M.
Published: July 2002

A fast and accurate ray model is developed for sound propagation in a downward refracting atmosphere. The model employs a new approach to the classification and computation of ray paths and caustic curves. The approach is valid for a large set of smooth sound-speed profiles, including realistic, nonlinear profiles such as the logarithmic profile. An ordered series of rays and caustics is found in this case, including caustics with a cusp. The sound-pressure field is computed by combining geometrical acoustics and the theory of caustics. The field on the illuminated side of a caustic is computed by modifying the geometrical-acoustics solution. The field on the shadow side of a caustic, i.e., the caustic diffraction field, is computed by extrapolation of various quantities into the shadow region. Different approaches to this extrapolation are considered. It is found that horizontal extrapolation gives the best results. The accuracy of the ray model is demonstrated by comparison with numerical solutions of the one-way wave equation. If caustic diffraction fields are ignored, discontinuities of more than 10 dB occur in the sound-pressure field.
The normalized interaural correlation: Accounting for NoSπ thresholds obtained with Gaussian and “low-noise” masking noise
Authors: Bernstein Leslie R. , van de Par Steven , Trahiotis Constantine
Published: July 2002

Recently, [J. Acoust. Soc. Am. 103, 2578–2589 (1998)] and [J. Acoust. Soc. Am. 103, 2573–2577 (1998)] independently reported that greater masking of interaurally phase-reversed (Sπ) tones was produced by diotic low-noise noise than by diotic Gaussian noise. Based on quantitative analyses, Eddins and Barber suggested that their results could not be accounted for by assuming that listeners’ judgments were based on constant-criterion changes in the normalized interaural correlation produced by adding the Sπ signal to the diotic masker. In particular, they showed that a model like the one previously employed by [J. Acoust. Soc. Am. 100, 3774–3784 (1996)] predicted an ordering of thresholds between the conditions of interest that was opposite to that observed. Bernstein and Trahiotis computed the normalized interaural correlation subsequent to half-wave, square-law rectification and low-pass filtering, the parameters of which were chosen to mimic peripheral auditory processing. In this report, it is demonstrated that augmenting the model by adding a physiologically valid stage of “envelope compression” prior to rectification and low-pass filtering provides a remedy. The new model not only accounts for the data obtained by Eddins and Barber (and the similar data obtained by Hall et al.), but also does not diminish the highly successful account of the comprehensive set of data that gave rise to the original form of the model. Therefore, models based on the computation of the normalized interaural correlation appear to remain valid because they can account, both quantitatively and qualitatively, for a wide variety of binaural detection and discrimination data.
Feasibility of using ring‐mounted Halcyon Linac for single‐isocenter/two‐lesion lung stereotactic body radiation therapy
Authors: Pokhrel Damodar , Webster Aaron , Mallory Richard , Visak Justin , Bernard Mark E. , McGarry Ronald C. , Kudrimoti Mahesh
Published: February 2022

Purpose

To demonstrate the plan quality and delivery efficiency of volumetric‐modulated arc therapy (VMAT) with the Halcyon Linac ring delivery system (RDS) in the treatment of single‐isocenter/two‐lesion lung stereotactic body radiation therapy (SBRT).

Materials/methods

Sixteen previously treated non‐coplanar VMAT single‐isocenter/two‐lesion lung SBRT plans delivered with SBRT‐dedicated C‐arm TrueBeam Linac were selected. Prescribed dose was 50 Gy to each lesion over five fractions with treatment delivery every other day and AcurosXB algorithm as the final dose calculation algorithm. TrueBeam single‐isocenter plans were reoptimized for Halcyon Linac with coplanar geometry. Both TrueBeam and Halcyon plans were normalized for identical combined target coverage and evaluated. Conformity indices (CIs), heterogeneity index (HI), gradient index (GI), gradient distance (GD), and D2cm were compared. The normal lung V5Gy, V10Gy, V20Gy, mean lung dose (MLD), and dose to organs at risk (OAR) were evaluated. Treatment delivery parameters, including beam‐on time, were recorded.

Results

Halcyon plans were statistically similar to clinically delivered TrueBeam plans. No statistical differences in target conformity, dose heterogeneity, or intermediate‐dose spillage were observed (all, p > 0.05). Halcyon plans, on average, demonstrated statistically insignificant reduced maximum dose to most adjacent OAR and normal lung. However, Halcyon yielded statistically significant lower maximal dose to the ribs (p = 0.041) and heart (p = 0.026), dose to 1 cc of ribs (p = 0.035) and dose to 5 cc of esophagus (p = 0.043). Plan complexity slightly increased as seen in the average increase of total monitor units, modulation factor, and beam‐on time by 480, 0.48, and 2.78 min, respectively. However, the estimated overall treatment time was reduced by 2.22 min, on average. Mean dose delivery accuracy of clinical TrueBeam plans and the corresponding Halcyon plans was 98.9 ± 0.85% (range: 98.1%–100%) and 98.45 ± 0.99% (range: 97.9%–100%), respectively, demonstrating similar treatment delivery accuracy.

Conclusion

SBRT treatment of synchronous lung lesions via single‐isocenter VMAT on Halcyon RDS is feasible and dosimetrically equivalent to clinically delivered TrueBeam plans. Halcyon provides excellent plan quality and shorter overall treatment time that may improve patient compliance, reduce intrafraction movement, improve clinic efficiency, and potentially offering lung SBRT treatments for underserved patients on a Halcyon only clinic.
A Variable Stiffness Magnetic Catheter Made of a Conductive Phase‐Change Polymer for Minimally Invasive Surgery
Authors: Piskarev Yegor , Shintake Jun , Chautems Christophe , Lussi Jonas , Boehler Quentin , Nelson Bradley J. , Floreano Dario
Published: February 2022

Variable stiffness (VS) is an important feature that significantly enhances the dexterity of magnetic catheters used in minimally invasive surgeries. Existing magnetic catheters with VS consist of sensors, heaters, and tubular structures filled with low melting point alloys, which have a large stiffness change ratio but are toxic to humans. In this paper, a VS magnetic catheter is described for minimally invasive surgery; the catheter is based on a novel variable stiffness thread (VST), which is made of a conductive shape memory polymer (CSMP). The CSMP is nontoxic and simultaneously serves as a heater, a temperature sensor, and a VS substrate. The VST is made through a new scalable fabrication process, which consists of a dipping technique that enables the fabrication of threads with the desired electrical resistance and thickness (with a step size of 70 µm). Selective bending of a multisegmented VST catheter with a diameter of 2.0 mm under an external magnetic field of 20 mT is demonstrated. Compared to existing proof‐of‐concept VS catheters for cardiac ablation, each integrated VST segment has the lowest wall thickness of 0.75 mm and an outer diameter of 2.0 mm. The segment bends up to 51° and exhibits a stiffness change factor of 21.
An MXene‐Based Metal Anode with Stepped Sodiophilic Gradient Structure Enables a Large Current Density for Rechargeable Na–O2 Batteries
Authors: He Xin , Ni Youxuan , Li Yixin , Sun Haoxiang , Lu Yong , Li Haixia , Yan Zhenhua , Zhang Kai , Chen Jun
Published: February 2022

The metal anode is the pivotal component for advanced sodium‐metal batteries such as Na–O2 batteries. Designing a 3D confinement scaffold is a promising strategy for constructing dendrite‐free sodium‐metal anodes; however, cycling stability at a large current density (>10 mA cm−2) is still difficult to realize. Herein, the design of new lightweight and fibrous hydroxylated Ti3C2 (h‐Ti3C2) MXene based scaffolds with stepped sodiophilic gradient structure (h‐M‐SSG) is reported, and its thickness can be controlled (80−250 µm). The sodiophilic gradient structure (adjusted by h‐Ti3C2) can effectively induce sodium ions to preferentially deposit at the bottom of the scaffold, thus inhibiting dendrite growth. h‐M‐SSG/Na‐based symmetrical batteries exhibit a low polarization voltage and long cycling life at a high current density (40 mA cm−2) and a high cut‐off capacity (40 mAh cm−2). Moreover, a Na–O2 battery with an h‐M‐SSG/Na anode exhibits a low potential gap of 0.137 V after 45 cycles at 1000 mA g−1 and 1000 mAh g−1. This deposition‐regulation strategy would inspire the design of 3D scaffolds for high‐performance sodium‐metal‐anode‐based batteries.
Significant Enhancement on the Proton Conduction Performance of Composite Membrane by Photoacid Molecules
Authors: Zhou Shu‐Fang , Wu Guo‐Mei , Zhang Chen‐Xi , Wang Qing‐Lun
Published: February 2022

Mimicking biological proton pump phenomenon to achieve stimulus‐responsive proton conduction behavior has received long‐term attention. The Pa@Zn‐MOF (Pa = photoacids) composites are successfully prepared through adsorption photoacid in Zn‐MOF, then, the composites are mixed into poly(vinyl alcohol) (PVA) to fabricate hybrid membranes Pa@Zn‐MOF‐PVA. When the hybrid membrane is activated through 375 nm violet light at room temperature, the value of proton conductivity after illumination is always superior to that before light irradiation. This phenomenon is attributed to the light‐induced ring‐closing reaction of the photoacid molecules to give the spiro‐forms (SPs) along with an abundant release of protons. The released protons jump into hydrogen bond networks and conveniently accelerate proton transport, resulting in higher proton conductivity. This is a noteworthy demonstration of dynamic control over proton conduction in composite membrane materials by adsorption of photoacid molecules in metal–organic framework.
Boosting Enhancement of the Electron–Phonon Coupling in Mixed Dimensional CdS/Graphene van der Waals Heterojunction
Authors: Li Zhonglin , Guo Shuai , Weller Dieter , Quan Sufeng , Yu Jing , Wang Runqiu , Wu Mengxuan , Jiang Jie , Wang Yingying , Liu Ruibin
Published: February 2022

Electron–phonon coupling plays a key role in affecting the properties of the semiconducting nanostructures, such as providing the possibility for obtaining higher superconducting transition temperatures. Here, using Raman, temperature‐dependent and polarized Raman scattering measurements, ultra‐strong electron–phonon coupling in 1D CdS nanowires and 2D graphene heterostructures is demonstrated. The intensity ratio of 2LO/1LO mode in CdS nanowires provides a spectroscopy‐based method to quantify electron–phonon coupling, the strength of which is temperature and polarization dependent. The intensity ratio mode of 2LO/1LO in heterostructure reached up to 8.95 when the incident laser polarization is parallel to the c‐axis of the nanowire. It is ≈2.37 times higher than in an individual nanowire. In addition, in situ and time‐resolved photoluminescence spectra demonstrate the dynamics of the exciton recombinations, providing a comprehensive understanding of the enhancement of electron–phonon coupling in heterostructures. Via optical waveguiding characterization, the graphene layer is demonstrated to not only be an ultrafast carrier transfer channel but also a low Fermi level channel that induces the formation of the built in electrical field, elevating the electron–phonon coupling. Such new mixed dimensional heterostructures illustrate a straightforward approach to enhance the electron–phonon coupling, which may be applied to many integrated superconducting photonic and optoelectronic devices.
Survey of Tetragonal Transition Metal Chalcogenide Hetero‐Bilayers for Promising Photocatalysts
Authors: Zhou Jia , Cheng Yanxin , Zhu Yaoyun
Published: February 2022

The formation of van der Waals (vdW) hetero‐bilayers have been emerging as unique structures to improve the performance of 2D layered nanomaterials for next‐generation photocatalysts. In this work, first‐principles calculations are employed to study the electronic and optical properties of a variety of tetragonal transition metal chalcogenide hetero‐bilayers. It is found that there are three stable semiconductor/semiconductor vdW hetero‐bilayers, and twenty‐one stable semiconductor/conductor vdW hetero‐bilayers. It is revealed that ZnS/ZnSe and ZnSe/ZnTe hetero‐bilayers possess a special band characteristic that is favorable for reducing the carrier recombination. In semiconductor/conductor hetero‐bilayers, the band edges of semiconductor are tuned via Schottky barrier, including p‐type and n‐type Schottky barrier. This work suggests that all hetero‐bilayers have an enhanced optical absorption within the visible light region, leading to more efficient solar energy harvesting. Based upon the theoretical calculations, tetragonal transition metal chalcogenide hetero‐bilayers will be great candidates as high performance photocatalysts for solar water splitting, as well as many other optoelectronic applications.
High‐Performance Functional Fe‐MOF for Removing Aflatoxin B1 and Other Organic Pollutants
Authors: Liu Yu‐Qing , Song Cheng‐Gang , Ding Gang , Yang Jian , Wu Jia‐Rui , Wu Gengxin , Zhang Ming‐Zhe , Song Chunli , Guo Lan‐Ping , Qin Jian‐Chun , Yang Ying‐Wei
Published: February 2022

Organic pollutants, including mycotoxins, organic dyes, and pesticide residues, are the most critical threats to the global environment. In particular, efficient adsorption based on synthetic nanomaterials is considered a versatile and green approach to control mycotoxins. This work systematically investigates the aflatoxin B1 (AFB1) removal capacity of MIL‐101(Fe), a typical type of metal‐organic framework (MOF) synthesized by solvothermal methods and possesses super‐high porosity and excellent dispersion in liquid. The experimental results demonstrate that as‐prepared MIL‐101(Fe) exhibits a much higher saturated loading capacity (30.58 mg g−1) toward AFB1 than other adsorbents described in the literature. Subsequently, the adsorption process is studied via isothermal and kinetic analyses. This work also evaluates the removal effect of MIL‐101(Fe) on organic dyes and pesticides compared to the other five MOFs; the results reveal that MIL‐101(Fe) possesses a diversity of pollutant adsorption. The molecular docking and interaction region indicator analysis is applied to reflect the interactions between AFB1 molecules and MIL‐101(Fe). This work will provide a simple and effective approach for AFB1 treatment and adsorption in wastewaters and offer new insights and perspectives to the practical applications of synthetic nanomaterials, MOFs in environmental management.
Supramolecular Peptide Nanofiber Hydrogels for Bone Tissue Engineering: From Multihierarchical Fabrications to Comprehensive Applications
Authors: Hao Zhuowen , Li Hanke , Wang Yi , Hu Yingkun , Chen Tianhong , Zhang Shuwei , Guo Xiaodong , Cai Lin , Li Jingfeng
Published: February 2022

Bone tissue engineering is becoming an ideal strategy to replace autologous bone grafts for surgical bone repair, but the multihierarchical complexity of natural bone is still difficult to emulate due to the lack of suitable biomaterials. Supramolecular peptide nanofiber hydrogels (SPNHs) are emerging biomaterials because of their inherent biocompatibility, satisfied biodegradability, high purity, facile functionalization, and tunable mechanical properties. This review initially focuses on the multihierarchical fabrications by SPNHs to emulate natural bony extracellular matrix. Structurally, supramolecular peptides based on distinctive building blocks can assemble into nanofiber hydrogels, which can be used as nanomorphology‐mimetic scaffolds for tissue engineering. Biochemically, bioactive motifs and bioactive factors can be covalently tethered or physically absorbed to SPNHs to endow various functions depending on physiological and pharmacological requirements. Mechanically, four strategies are summarized to optimize the biophysical microenvironment of SPNHs for bone regeneration. Furthermore, comprehensive applications about SPNHs for bone tissue engineering are reviewed. The biomaterials can be directly used in the form of injectable hydrogels or composite nanoscaffolds, or they can be used to construct engineered bone grafts by bioprinting or bioreactors. Finally, continuing challenges and outlook are discussed.
Superelongation of Liquid Metal
Authors: Li Xiangpeng , Cao Lu , Xiao Bing , Li Fangxia , Yang Junhui , Hu Jie , Cole Tim , Zhang Yuxin , Zhang Mingkui , Zheng Jiahao , Zhang Shiwu , Li Weihua , Sun Lining , Chen Xiaoqian , Tang Shi‐Yang
Published: February 2022

The ability to control interfacial tension electrochemically is uniquely available for liquid metals (LMs), in particular gallium‐based LM alloys. This imparts them with excellent locomotion and deformation capabilities and enables diverse applications. However, electrochemical oxidation of LM is a highly dynamic process, which often induces Marangoni instabilities that make it almost impossible to elongate LM and manipulate its morphology directly and precisely on a 2D plane without the assistance of other patterning methods. To overcome these limitations, this study investigates the use of an LM–iron (Fe) particle mixture that is capable of suppressing instabilities during the electrochemical oxidation process, thereby allowing for superelongation of the LM core of the mixture to form a thin wire that is tens of times of its original length. More importantly, the elongated LM core can be manipulated freely on a 2D plane to form complex patterns. Eliminating Marangoni instabilities also allows for the effective spreading and filling of the LM–Fe mixture into molds with complex structures and small features. Harnessing these excellent abilities, a channel‐less patterning method for fabricating elastomeric wearable sensors is demonstrated to detect motions. This study shows the potential for developing functional and flexible structures of LM with superior performance.
Dielectric Loss Mechanism in Electromagnetic Wave Absorbing Materials
Authors: Qin Ming , Zhang Limin , Wu Hongjing
Published: February 2022

Electromagnetic (EM) wave absorbing materials play an increasingly important role in modern society for their multi‐functional in military stealth and incoming 5G smart era. Dielectric loss EM wave absorbers and underlying loss mechanism investigation are of great significance to unveil EM wave attenuation behaviors of materials and guide novel dielectric loss materials design. However, current researches focus more on materials synthesis rather than in‐depth mechanism study. Herein, comprehensive views toward dielectric loss mechanisms including interfacial polarization, dipolar polarization, conductive loss, and defect‐induced polarization are provided. Particularly, some misunderstandings and ambiguous concepts for each mechanism are highlighted. Besides, in‐depth dielectric loss study and novel dielectric loss mechanisms are emphasized. Moreover, new dielectric loss mechanism regulation strategies instead of regular components compositing are summarized to provide inspiring thoughts toward simple and effective EM wave attenuation behavior modulation.
Photothermal‐Assisted Photocatalytic Nitrogen Oxidation to Nitric Acid on Palladium‐Decorated Titanium Oxide
Authors: Zhang Xuerui , Shi Run , Li Zhenhua , Zhao Jiaqing , Huang Huining , Zhou Chao , Zhang Tierui
Published: February 2022

Industrial nitric acid production involves multistep processes operating at high temperatures and pressures. Photocatalysis offers an alternative approach for directly transforming nitrogen molecules into nitrogen‐containing compounds under ambient conditions but still faces visible light utilization and product selectivity restrictions. Herein, a tandem photothermal‐assisted photocatalytic nitrogen oxidation system based on palladium‐decorated hydrogenated titanium oxide is fabricated, in which nitric acid is produced as the only nitrogen fixation product. The yield of nitric acid increases from 0.56 µmol g−1 h−1 at room temperature to 4.58 µmol g−1 h−1 (1.42 ppm) at 200 °C, accompanied by an enhanced quantum yield from 0.24% to 0.99% at 350 nm. The photothermal effect of palladium nanoparticles promotes the generation of superoxide radicals and nitrogen oxide intermediates in the gas–solid phase nitrogen oxidation process and contributes to improved nitric acid productivity. Therefore, the photothermal‐assisted photocatalytic nitrogen oxidation strategy opens new avenues toward developing clean and energy‐saving nitric acid production.
Trends in fatal occupational injuries in Latino/a workers relative to other groups, North Carolina 2000–2017
Authors: Richey Morgan M. , Golightly Yvonne , Marshall Stephen W. , Novicoff Wendy , Keil Alexander P. , Nocera Maryalice , Richardson David B.
Published: February 2022

Background

Latino/a workers may experience higher fatal occupational injury rates than non‐Latino/a workers. In North Carolina, the Latino/a population more than doubled between 2000 and 2017. We examined fatal occupational injuries among Latino/a and non‐Latino/a workers in North Carolina over this period.

Methods

Information on fatal occupational injuries was abstracted from records of the North Carolina Office of the Chief Medical Examiner and the death certificate records held by the North Carolina Office of Vital Records. Estimates of the working population were derived from the decennial census and American Community Survey. Estimates of annual rates of fatal occupational injury for the period January 1, 2000 to December 31, 2017 were derived for Latino/a workers and compared to Black and White workers not identified as Latino/a.

Results

Over the study period, 1,783 fatal occupational injuries were identified among non‐Latino/a workers and 259 fatal occupational injuries among Latino/a workers in North Carolina. The majority of fatal occupational injuries among Latino/a workers occurred among males employed in construction and agriculture. While the fatal occupational injury rate among Latino/a workers declined over the study period, the rate among Latino/a workers was higher than among non‐Latino/a White and Black workers; moreover, fatal occupational injury rates for Latino/a workers trended upwards during the most recent years of the study period.

Conclusions

Latino/a workers in North Carolina have the highest fatal occupational injury rate of any race/ethnicity group.
Oriented Nanoarchitectonics of Bacteriorhodopsin for Enhancing ATP Generation in a FoF1‐ATPase‐Based Assembly System
Authors: Li Zibo , Xu Xia , Yu Fanchen , Fei Jinbo , Li Qiang , Dong Mingdong , Li Junbai
Published: February 2022

Energy conversion plays an important role in the metabolism of photosynthetic organisms. Improving energy transformation by promoting a proton gradient has been a great challenge for a long time. In the present study, we realize a directional proton migration through the construction of oriented bacteriorhodopsin (BR) microcapsules coated by FoF1‐ATPase molecular motors through layer‐by‐layer (LBL) assembly. The changes in the conformation of BR under illumination lead to proton transfer in a radial direction, which generates a higher proton gradient to drive the synthesis of adenosine triphosphate (ATP) by FoF1‐ATPase. Furthermore, to promote the photosynthetic activity, optically matched quantum dots were introduced into the artificial coassembly system of BR and FoF1‐ATPase. Such a design creates a new path for the use of light energy.
Direct Dehydrogenative Access to Unsymmetrical Phenones
Authors: Yu Congjun , Huang Raolin , Patureau Frederic W.
Published: February 2022

The first non‐directed dehydrogenative phenone coupling method of methylarenes with aromatic C−H bonds, displaying a large substrate scope, is herein reported. This reaction represents a far more direct atom‐ and step‐efficient alternative to the classical Friedel–Crafts or Suzuki–Miyaura derived acylation reactions. The method can be carried out on a gram scale and was successfully applied to the synthesis of several Ketoprofen drug analogues.
Construction of H6PW9V3O40@rht‐MOF‐1 for deep oxidative desulfurization of fuel oil
Authors: Bai Yiyang , Xin Yuxiang , Liu Jiabin , Ma Liqiang , Li Guangming
Published: February 2022

Deep desulfurization is impending for environmental conservation by way of reducing supplied emissions from fuel oil. Developing new and effective catalysts on deep desulfurization is still a great changeling. In this piece of work, a series of three H3+nPW(12‐n)VnO40@rht‐MOF‐1 have been synthesized by one‐pot self‐assembly hydrothermal reaction of CuCl2·2H2O and 5‐tetrazolyl isophthalic acid (H3TZI) with three H3+nPW(12‐n)VnO40 (polyoxometalates [POMs]), respectively. X‐ray crystallographic analysis reveals that the POMs have been successfully encapsulated in the cages of rht‐MOF‐1. The affording complex 3, as heterogeneous catalyst, is able to effectively catalyze the extraction catalytic oxidation desulfurization system (ECODS) of model oil and real fuel oil under mild reaction conditions. The remarkable encapsulation of POMs in rht‐MOF‐1 resulted in the heterogeneous catalysis, enabling it to be recycled in the system. The reaction kinetics has been investigated, and the redial reaction mechanism has been verified by electron paramagnetic resonance (EPR) analysis and radical quenching experiments. This approach provides an easy and effective route on developing heterogeneous catalysts that could be applied in the deep ECODS of fuel oil.
Study on two‐stage stretching strategy for microstructure improvement of polytetrafluoroethylene hollow fiber membrane
Authors: Jia Jingxuan , Zhou Meiqing , Liu Dandan , Li Meng , Kang Guodong , Cao Yiming
Published: February 2022

Polytetrafluoroethylene (PTFE) has excellent chemical resistance, thermal stability as well as hydrophobicity, and is regarded as a good material for membrane fabrication. PTFE hollow fiber membrane is commonly prepared by the paste extrusion–stretching–sintering process, where the stretching temperature is usually fixed in existing reports. In this paper, a new two‐stage stretching method (first at 50°C and then at 200°C) was proposed to optimize the microstructure of PTFE hollow fiber membranes. Meanwhile, the stretching experiments at low‐temperature (50°C) and high‐temperature (200°C) were also conducted for comparison. The chemical composition, surface morphology, surface porosity, overall porosity, maximum pore size, water contact angle, and mechanical property were discussed. Moreover, the ethanol permeation flux and bovine serum albumin (BSA) rejection of PTFE hollow fiber membranes prepared from different stretching manners were tested. The results showed that with the increase of stretching ratio, the porosity, and pore size gradually increased for all three membranes. However, for a specific stretching ratio, the membrane fabricated by two‐stage stretching process exhibited better comprehensive properties in terms of porosity and pore size, that is, higher porosity than the 50°C method and smaller pore size than the 200°C method. As stretching ratio was 2.0, the ethanol permeation flux and BSA rejection was 2467 L/m2 h and 95%, respectively. Overall, the PTFE hollow fiber prepared from “two‐stage” stretching exhibited comparable BSA rejection (both around 95%) and much higher permeation flux (increased by 43.1%) compared to the sample prepared by low‐temperature stretching at 50°C, and meanwhile, comparable permeation flux (decreased by 10.8%) and higher BSA rejection (95% against 81%) compared to the sample prepared by high‐temperature stretching at 200°C. The proposed method provided a good reference for the microstructure improvement of PTFE hollow fiber membrane fabricated by paste extrusion–stretching–sintering technology.
Visual working memory performance is intact across development in autism spectrum disorder
Authors: Lynn Andrew , Luna Beatriz , O'Hearn Kirsten
Published: February 2022

Autism spectrum disorder (ASD) is associated with atypical visual processing and deficits in working memory (WM). Visual WM performance typically improves between childhood and adulthood, but such improvement may be atypical in ASD. To better understand how visual WM develops, we used a well‐established change detection task across multiple visual features. We examined visual WM for color, shape, and pattern in children, adolescents, and adults with and without ASD. VWM capacity and performance for all visual features improved across age similarly for both the TD and ASD groups. While performance was better on set size 4 trials than set size 8 trials for color, shape, and no change trials, such an effect was not evident for pattern change trials. Overall, the present findings suggest that VWM for different visual features may be intact across development in ASD. The ability to hold multiple objects in mind (WM) improves across typical development, but it remains unclear whether such improvement occurs in ASD. We found that developmental improvements in WM for different types of object details (e.g., color, shape, and pattern) is generally similar for both ASD and typical development.

Lay Summary

The ability to hold multiple objects in mind (working memory [WM]) improves across typical development, but it remains unclear whether such improvement occurs in autism spectrum disorder (ASD). We found that developmental improvements in WM for different types of object details (e.g., color, shape, pattern) is generally similar for both ASD and typical development.
Engineered yeast for efficient de novo synthesis of 7‐dehydrocholesterol
Authors: Qu Lisha , Xiu Xiang , Sun Guoyun , Zhang Chenyang , Yang Haiquan , Liu Yanfeng , Li Jianghua , Du Guocheng , Lv Xueqin , Liu Long
Published: February 2022

The synthesis of vitamin D3 precursor 7‐dehydrocholesterol (7‐DHC) by microbial fermentation has much attracted attention owing to its advantages of environmental protection. In this study, Saccharomyces cerevisiae was engineered for a de novo biosynthesis of 7‐DHC. First, seven essential genes (six endogenous genes and one heterologous gene) were overexpressed, and the ROX1 gene (heme‐dependent repressor of hypoxic genes) was knocked out. The resulting strain produced 82.6 mg/L 7‐DHC from glucose. Then, we predicted five gene knockout targets for 7‐DHC overproduction by the reconstruction of genome‐scale metabolic model. GDH1 gene knockout increased the 7‐DHC titer from 82.6 to 101.5 mg/L, and the specific growth rate of the ΔGDH1 mutant was also increased by 28%. Next, Ty1 transposon in S. cerevisiae was applied to increase the copies of the ERG1 gene and DHCR24 gene, resulting in a 120% increase in 7‐DHC titer to 223.3 mg/L. Besides, to optimize the metabolic flux distribution, Clustered Regularly Interspaced Short Palindromic Repeats interference (CRISPRi) system was used to dynamically inhibit the competitive pathway, and the best binding site of ERG6 (delta (24)‐sterol C‐methyltransferase) promoter was screened out. The OD600 value of ERG6 regulated cells increased by 43% than knocking out ERG6 directly, and 7‐DHC titer increased to 365.5 mg/L in a shake flask. Finally, the 7‐DHC titer reached 1328 mg/L in 3‐L bioreactor and the specific titer of 7‐DHC reached up to 114.7 mg/g dry cell weight). Overall, this study constructed a yeast chassis for the highly efficient production of 7‐DHC by systems metabolic engineering.
Referral process to further evaluate poor sleep in breast cancer survivors
Authors: Otte Julie L. , Chernyak Yelena , Johns Shelley A. , Jackson Lea' , Ludwig Kandice K. , Dodson Jill , Manchanda Shalini , Bufink Elizabeth , Draucker Claire
Published: February 2022

Objective

Breast cancer survivors (BCS) are twice as likely to report symptoms of poor sleep as those without cancer. However, sleep disorders are under‐assessed and under‐treated among BCS. The purpose of this study was to determine the portion of BCS who completed referral visits to a sleep specialist and identify the acceptability, facilitators, and barriers to the screening and referral process.

Methods

BCS, who reported having sleep problems, completed questionnaires to screen for symptoms suggestive of sleep disorders. Those with symptoms suggestive of sleep apnea, movement disorders, narcolepsy, insomnia syndrome, or circadian disorders, they were referred to a sleep medicine physician or behavioral sleep medicine psychologist. Two months after the referral, participants were interviewed about their perceptions of the acceptability, barriers, and facilitators to sleep screenings and referrals.

Results

Of 34 BCS assessed for eligibility, 29 were eligible and had sleep problems. Only eight of 29 participants (27.6%) completed the sleep referral process. Most thought the screening and referral process was acceptable. However, BCS identified barriers to completing the referral visit, including time, not seeing the need for treatment, insurance/sick leave concerns, and distance/transportation.

Conclusion

Adequate evaluation and treatment of sleep disorders in BCS are rare. Creative solutions to address barriers to timely sleep referrals are needed to reduce long‐term negative consequences of inadequate sleep.
Impacts of weathering/preharvest sprouting in the field on the milling and flour quality of soft wheats, and resulting baking performance for soft wheat‐based baked products
Authors: Kweon Meera , Slade Louise , Levine Harry
Published: February 2022

Background and Objectives

Preharvest sprouting (PHSing) of wheat induces more heterogeneous germination in the field than in a controlled laboratory setting, but the former phenomenon has not been studied extensively to date. In the present study, the impacts of field‐weathering (FWing)/PHSing in soft wheats on resulting flour quality and baking performance, for soft wheat‐based baked products, were explored for twelve soft wheat cultivars.

Findings

FWing/PHSing in soft wheats significantly affected test weight, break flour yield, falling number, α‐amylase activity, and solvent retention capacity. Starch‐pasting profiles for flour samples with different wheat harvest times appeared to potentially show four groups of behavior. However, the impacts of FWing/PHSing in the wheats studied were negligible on the resulting baking performance of pancakes, cookies, and crackers, but were dramatic for Japanese‐type sponge cake.

Conclusions

Effects of FWing/PHSing in soft wheats on resulting wheat and flour quality, milling performance, and baking performance were confirmed. The set of tested flours in the study, milled from field‐weathered (FWed)/PH sprouted (Sed) soft wheat grains, exhibited four groups of behavior in starch‐pasting profiles, which varied significantly with wheat genotype.

Significance and Novelty

A comprehensive study of FWed/PHSed soft wheats, conducted to cover different wheat genotypes and different types of baked products, is reported here for the first time.
Novel PKLR missense mutation (A300P) causing pyruvate kinase deficiency in an Omani Kindred—PK deficiency masquerading as congenital dyserythropoietic anemia
Authors: Fawaz Naglaa , Beshlawi Ismail , Alqasim Alauldeen , Zachariah Mathew , Russo Roberta , Andolfo Immacolata , Gambale Antonella , Pathare Anil , Iolascon Achille
Published: February 2022

We report herein a child with transfusion‐dependent chronic anemia, the cause of which was difficult to establish because of his transfusion dependency. The clinical and laboratory features suggested a chronic nonspherocytic hemolytic anemia (CNSHA) with bone marrow features suggestive of congenital dyserythropoietic anemia (CDA). DNA studies, however, revealed the underlying condition to be due to a novel mutation in the PKLR gene responsible for pyruvate kinase deficiency (PKD). Molecular investigations by a targeted next‐generation sequencing (t‐NGS) using a custom panel of 71 genes involved in the red blood cell (RBC) disorders revealed that the patient was homozygous for a novel missense mutation c.898G>C, p.Ala300Pro, whereas both his parents were heterozygous for the same mutation.