bluuebunny/crossref_metadata_2025 huggingface dataset:
Shake‐up and shake‐off excitations with associated electron losses in X‐ray studies of proteins
Authors: Persson Petter , Lunell Sten , Szöke Abraham , Ziaja Beata , Hajdu Janos
Published: July 2002

Photoionization of an atom by X‐rays usually removes an inner shell electron from the atom, leaving behind a perturbed “hollow ion” whose relaxation may take different routes. In light elements, emission of an Auger electron is common. However, the energy and the total number of electrons released from the atom may be modulated by shake‐up and shake‐off effects. When the inner shell electron leaves, the outer shell electrons may find themselves in a state that is not an eigen‐state of the atom in its surroundings. The resulting collective excitation is called shake‐up. If this process also involves the release of low energy electrons from the outer shell, then the process is called shake‐off. It is not clear how significant shake‐up and shake‐off contributions are to the overall ionization of biological materials like proteins. In particular, the interaction between the outgoing electron and the remaining system depends on the chemical environment of the atom, which can be studied by quantum chemical methods. Here we present calculations on model compounds to represent the most common chemical environments in proteins. The results show that the shake‐up and shake‐off processes affect ∼20% of all emissions from nitrogen, 30% from carbon, 40% from oxygen, and 23% from sulfur. Triple and higher ionizations are rare for carbon, nitrogen, and oxygen, but are frequent for sulfur. The findings are relevant to the design of biological experiments at emerging X‐ray free‐electron lasers.
Automated classification of clustered microcalcifications into malignant and benign types
Authors: Veldkamp Wouter J. H. , Karssemeijer Nico , Otten Johannes D. M. , Hendriks Jan H. C. L.
Published: July 2002

The objectives in this study were to design and test a fully automated method for classification of microcalcification clusters into malignant and benign types, and to compare the method's performance with that of radiologists. A novel aspect of the approach is that the relative location and orientation of clusters inside the breast was taken into account for feature calculation. Furthermore, correspondence of location of clusters in mediolateral oblique (MLO) and cranio‐caudal (CC) views, was used in feature calculation and in final classification. Initially, microcalcifications were automatically detected by using a statistical method based on Bayesian techniques and a Markov random field model. To determine malignancy or benignancy of a cluster, a method based on two classification steps was developed. In the first step, classification of clusters was performed and in the second step a patient based classification was done. A total of 16 features was used in the study. To identify meaningful features, a feature selection was applied, using the area under the receiver operating characteristic (ROC) curve value) as a criterion. For classification the k‐nearest‐neighbor method was used in a leave‐one‐patient‐out procedure. A database of 192 mammograms with 280 true positive detected microcalcification clusters was used for evaluation of the method. The set consisted of cases that were selected for diagnostic work up during a 4 year period of screening in the Nijmegen region (The Netherlands). Because of the high positive predictive value in the screening program this set did not contain obvious benign cases. The method's best patient‐based performance on this set corresponded with using nine features. A subset of the data set, containing mammograms from 90 patients, was used for comparing the computer results to radiologists' performance. Ten radiologists read these cases on a light‐box and assessed the probability of malignancy for each patient. All participants had experience in clinical mammography and participated in our observer study during the last 2 days of a 2‐week training session leading to screening mammography certification. Results on the subset showed that the method's performance was considerably higher than that of the radiologists
Trainable rule‐based algorithm for the measurement of joint space width in digital radiographic images of the knee
Authors: Duryea J. , Li J. , Peterfy C. G. , Gordon C. , Genant H. K.
Published: July 2002

The progression of osteoarthritis (OA) can be monitored by measuring the minimum joint space width (mJSW) between the edges of the femoral condyle and the tibial plateau on radiographs of the knee. This is generally performed by a trained physician using a graduated magnifying lens and is prone to the subjectivity and variation associated with observer measurement. We have developed software that performs this measurement automatically on digitized radiographs. The test data consisted of 180 digitized radiographs of the knee (90 duplicate acquisitions) from 18 normal (nonarthritic) subjects and 38 images from 10 subjects with OA. These were digitized and manually cropped so that the images were free of nonanatomical structures and the knee was approximately centered. The software first determined the edge of the femoral condyle on 400 μm pixel subsampled images. Contours marking the location of the tibial plateau in the medial compartment were found on 100 μm images using the femoral edge as a reference. The algorithm was trained using an independent but similar data set and using a jackknife approach with the test data. The results were compared to contours drawn by a trained reader and the duplicate acquisitions were used to measure the reproducibility of the mJSW measurement. The reproducibility was 0.16 mm and 0.18 mm for normal and osteoarthritic knees, respectively, representing an improvement of approximately a factor of 2 over manual measurement. The algorithm also showed excellent agreement with the hand‐drawn contours and with mJSW determined by the manual method.
The great Copernican cliché
Authors: Danielson Dennis R.
Published: July 2002

For more than three centuries scientists, historians, and popularizers of science have been repeating the claim that Copernicus “dethroned” earth from its “privileged” central position in the universe. However, a survey of pre-Copernican natural philosophy (which viewed the earth as located in a cosmic sump) and of Copernicans’ own account of the axiological meaning of the new heliocentric astronomy (which exalted earth to the dance of the stars) demonstrates that the cliché about earth’s “demotion” is unwarranted and fit to be discarded.
Acoustical cavity excitation
Authors: Levine Harold
Published: July 2002

A tutorial exposition is given of cavity excitations and it is shown that relatively simple analytical solutions for the excitation of acoustic fields in cavities with lossy walls can be obtained for a broad class of such cavities. The standard analytic procedure whereby one expresses the acoustic field as a sum over the eigenmodes of the cavity is reviewed and its limitations are pointed out. An alternate procedure is to seek to make use of Green’s functions depending on a single coordinate and to not express such Green’s functions as sums over eigenfunctions. Instead, one expresses the Green’s function as a closed form function that has a discontinuous slope at the value of the coordinate corresponding to the source location. Although the class of cavities for which this approach is possible is limited, it is sufficiently broad to be of intrinsic interest and the results may be helpful to those seeking benchmark solutions and analytic insight. Displayed examples are for cavities whose shapes are spheres and cylinders, with interior monopole, dipole, line, and distributed sources. The formulation yields simple expressions for the total power absorbed by the cavity walls.
SIM—simultaneous inverse filtering and matching of a glottal flow model for acoustic speech signals
Authors: Fröhlich Matthias , Michaelis Dirk , Strube Hans Werner
Published: July 2002

A new method “simultaneous inverse filtering and model matching” (SIM) is proposed that allows one to calculate voice source measures without any user interaction. It is based on the discrete all-pole modeling (DAP) technique for inverse filtering (IF), which is modified to include a model of the glottal flow as integral part [LF model, Fant et al., STL-QPSR (Stockholm) 4/1985, 1–13 (1986)]. As the correct LF parameters are initially unknown, they are estimated in an iterative procedure using multi-dimensional optimization techniques that are initialized according to the results of an exhaustive search. The error criteria applied reflect how well the IF is performed after the spectral contribution of the glottal flow has been removed. The resulting optimal LF parameter constellation serves as the basis to calculate 11 voice source measures. The performance was evaluated using synthesized signals and recordings of natural utterances. For the synthesized signals, the accuracy to reproduce the original parameters was high (correlations exceeding 0.88) for measures where the starting point of the glottal cycle did not enter explicitly. Errors were smaller compared to conventional estimation methods where the measures were estimated from the IF signal. The analysis of natural utterances indicates that problems still exist with regard to robustness, but that under advantageous conditions the open quotient, the speed quotient, the closing quotient, the parabolic spectral parameter, and the negative peak amplitude of the glottal flow derivative can indeed be determined automatically by the SIM method.
Coupled-mode solutions in generalized ocean environments
Authors: Stotts Steven A.
Published: July 2002

This paper presents the application of the differential equation approach to solving the second-order coupled-mode equations in inhomogeneous ocean environments. The model incorporates sound velocity profile points to construct depth-dependent, piecewise linear, ocean and bottom environments along a range grid. Modal solutions are evaluated in terms of Airy functions. The formalism to evaluate analytically the mode-coupling coefficients is presented. Comparisons to conventional expressions of the coefficients are made. The integro-differential form of the coupled equations is solved using an approach developed in nuclear theory that incorporates the Lanczos method [Knobles, J. Acoust. Soc. Am. 96, 1741–1747 (1994)]. Demonstration of the practicality of this approach is made by applying the results in actual calculations with realistic ocean environments. The formalism to evaluate analytically the mode-coupling coefficients is presented. Several benchmark examples were examined in order to validate the model and are discussed, including propagation over a hill, benchmark wedge problems, and a range-varying sound speed profile benchmark. The importance of this model is also demonstrated by the physical insight gained in having a coupled-mode approach to solving range-dependent problems.
Generation of an acoustically bright zone with an illuminated region using multiple sources
Authors: Choi Joung-Woo , Kim Yang-Hann
Published: July 2002

This article addresses the way in which we can generate an “acoustically bright zone” in a space. The bright zone is defined as the volume where we can have higher acoustic energy than in other space. A method is proposed to generate the bright zone by controlling multiple monopole sources. Two kinds of cost functions involved with acoustic brightness are defined. One is the ratio of the brightness of a zone to the input power, and the other expresses the “contrast” between the bright zone and the other space. Through eigenvalue analysis, the optimal volume velocity distribution of the monopoles has been obtained.
A direct mixed-body boundary element method for packed silencers
Authors: Wu T. W. , Cheng C. Y. R. , Zhang P.
Published: July 2002

Bulk-reacting sound absorbing materials are often used in packed silencers to reduce broadband noise. A bulk-reacting material is characterized by a complex mean density and a complex speed of sound. These two material properties can be measured by the two-cavity method or calculated by empirical formulas. Modeling the entire silencer domain with a bulk-reacting lining will involve two different acoustic media, air and the bulk-reacting material. Traditionally, the interior silencer domain is divided into different zones and a multi-domain boundary element method (BEM) may be applied to solve the problem. However, defining different zones and matching the elements along each interface is tedious, especially when the zones are intricately connected. In this paper, a direct mixed-body boundary element method is used to model a packed silencer without subdividing it into different zones. This is achieved by summing up all the integral equations in different zones and then adding the hypersingular integral equations at interfaces. Several test cases, including a packed expansion chamber with and without an absorbing center bullet, and a parallel baffle silencer, are studied. Numerical results for the prediction of transmission loss (TL) are compared to experimental data.
Wave propagation and attenuation in Herschel–Venturi tubes
Authors: Selamet A. , Easwaran V.
Published: July 2002

Wave propagation and attenuation in a classical flow metering device, the Herschel–Venturi tube, is investigated analytically and experimentally. The analytical results are shown to compare well with the experimental observations for anechoically terminated Herschel–Venturi tubes. In the absence of flow, the Taylor series approximations to the governing differential equations and the stepwise expansion and contraction method are shown to be identical. The effect of mean flow on the wave attenuation performance of Herschel–Venturi tubes is also studied in terms of a solution obtained by the Runge–Kutta method, and the applicability of the stepwise expansion and contraction method is discussed with the mean flow through the duct.
Local admittance model for acoustic scattering from a cylindrical shell with many internal oscillators
Authors: Bucaro J. A. , Romano A. J. , Sarkissian A. , Photiadis D. M. , Houston B. H.
Published: July 2002

This paper considers whether local admittance fluctuations can explain the acoustic scattering from a submerged shell with many internal oscillators observed by Bucaro et al. [Proc. ASME, Noise Control and Acoustics Div., NCA 22, 87–92 (1996)] and Photiadis et al. [J. Acoust. Soc. Am. 101, 895–899 (1997)]. The scattering is computed using a Helmholtz-based approach for a locally reacting surface whose admittance is affected by the random placement of internal oscillators. The predicted scattering patterns versus frequency and monostatic scattering angle are shown to agree with what is observed in the measured results.
The contrast mechanism of bond defects with the scanning acoustic microscopy
Authors: Wang Lugen
Published: July 2002

This paper discusses the theoretical aspects of the scanning acoustic microscopy response when used to inspect layered solids with bond defects. By using the transfer matrix method and spring boundary conditions, the solution of elastic wave scattering by an interface weakness in a layered solid has been presented in the wave number domain. The microscopy response has been calculated by combining this scattering solution with the scanning acoustic microscopy model. The results show that the acoustic microscopy response is sensitive to normal bond compliance in all defocus range. However, the shear bond compliance has influence on the response only at large defocus. The relations between the microscopy response and bond compliances significantly depend on the defect width, shape, and the material properties of the layer and substrate.
Experimental results for detection of buried objects at low grazing angles
Authors: Fox Warren L. J. , Maguer Alain
Published: July 2002

Extension of buried object detection sonar system concepts to include low grazing angle geometries (i.e., beyond critical angle) would provide useful gains in coverage rate, provided acceptably high detection probabilities can be maintained for sufficiently low probabilities of false alarm. Several experiments have recently been conducted at shallow water sites with sandy seabottoms near Elba Island, Italy, in order to study the acoustic backscattering characteristics of the seabed and buried targets in a range of grazing angles both above and below the nominal critical angle of the seabed. A parametric sonar with significant secondary frequency source levels in the range 2–16 kHz was used (the size of the targets yielded ka values also in the approximate range 2–16). Modeling results for buried objects have shown that subcritical insonification can produce relatively high monostatic echo levels, especially at lower frequencies where the evanescent field is strongest. Some results of the experiments are discussed which show promising SNR improvements for subcritical cases when the lowest parts of the frequency band are emphasized, in empirical agreement with the models.
Fluid flow in a dynamic mechanical model of the vocal folds and tract. I. Measurements and theory
Authors: Barney Anna , Shadle Christine H. , Davies P. O. A. L.
Published: July 2002

In this study, aerodynamic and acoustic measurements were obtained in a dynamic mechanical model of the larynx and vocal tract. The model consisted of a uniform duct, intersected by a pair of sinusoidally oscillating shutters. A controlled airflow along the duct was periodically disturbed by the action of the shutters and pressure, and flow velocity measurements were obtained in the region downstream. The velocity field in the duct could be decomposed into three distinct components: a mean flow, a fluctuating acoustic particle velocity, and a fluctuating nonacoustic velocity associated with the transport of vortices along the duct at the local mean flow velocity. Two theoretical models for sound radiation from the duct exit were investigated. The first was based on the in-duct acoustic field alone and was unable to provide a realistic prediction of the measured, radiated sound field except at the first formant of the duct. In the second a simple description of sound generation due to the interaction of vortices with the duct exit was added. In this case much closer prediction of the measured values was achieved, leading to the conclusion that the interaction of the nonacoustic velocity fluctuation with the duct boundaries results in a significant additional source of acoustic energy located in the region of the duct exit.
Model-based seafloor identification with parametric sonar data: Experimental results
Authors: Caiti Andrea , Bergem Oddbjorn , Pouliquen Eric , Michelozzi Enzo
Published: July 2002

A method is proposed to estimate the geoacoustic parameters of the uppermost seafloor strata using normal-incidence backscattered acoustic data obtained with a parametric sonar in the 4–12 kHz frequency range. A model-based identification approach has been pursued. The time-domain backscattering model BORIS [Bergem et al., SACLANTCEN Memorandum SM-328 (1997)] has been selected as a forward model. A specific wavelet transform has been defined in order to obtain a significant measure of the discrepancy between data and model predictions in the wavelet-transformed domain. This discrepancy is minimized as a function of the bottom parameters. The technique has been tested on experimental data gathered in different locations in order to assess its perfomance on different bottom types. Identification results have been compared with independent ground truth collected by core analysis and video camera inspection. The comparison shows excellent agreement between acoustically determined parameters and ground truth. [This work has been partially supported by European Union, Contract No. MAS3-CT95-046, project ISACS.]
Feedback path variability modeling for robust hearing aids
Authors: Rafaely B. , Roccasalva-Firenze M. , Payne E.
Published: July 2002

Acoustic feedback is a common problem in hearing aids with vented earmolds. Hearing aids designed to work under normal conditions become unstable when the feedback path varies under changing conditions. A comprehensive study of the variability of the feedback path under various conditions and for different users is presented in this paper. A multiplicative uncertainty bound widely used in H-infinity robust control is suggested to model the variations, which is then used to formulate a robust stability condition for the hearing aid. The upper limit of the closed-loop acoustic gain of the hearing aid for maintaining robust stability is also derived. Examples of robust constant amplification hearing aids, which maintain stability in the face of the given variations in the feedback path, are presented. The robust stability condition is also suggested as a tool to design more robust digital hearing aids.
Structure–property relationships in food biopolymer gels and solutions
Authors: Ross-Murphy Simon B.
Published: July 2002

This paper serves as a review of work performed in the author’s and his collaborators’ laboratories over the last 15 years on the general topic of structure/property relationships for biopolymer (including food biopolymer) solutions and gels. In the first part, we describe how small deformation oscillatory measurements have enabled a distinction to be made between ‘‘entanglement networks,’’ ‘‘strong’’ and ‘‘weak’’ gels used, respectively, as food thickeners, gels, and stabilizers. At small enough strains both strong and weak gel systems give essentially the same mechanical spectrum, with G′≳G″, and with both moduli largely independent of frequency. However, the deformation dependence of these two classes of materials is very different. At large deformations strong gels will rupture and fail, while weak gels flow without fracture and but show recovery of solid (gel-like) character. In this paper the various classes of food biopolymers are described, and their rheological properties related to differences in structure. The final part contrasts the behavior of a weak gel (xanthan gum) and entanglement solution (guar gum). This distinction is confirmed by their respective responses in start shear experiments. Guar solutions behave much like most other polymer solutions, whereas xanthan solutions show a very pronounced overshoot peak at low strains, and very long peak overshoot recovery times.
Rheology of suspensions of weakly attractive particles: Approach to gelation
Authors: Rueb C. J. , Zukoski C. F.
Published: July 2002

The flow properties of suspensions of weakly attractive particles are investigated as a function of volume fraction and strength of interparticle attraction. The suspensions are composed of uniform silica spheres with covalently bound octadecyl chains with diameters 100–125 nm suspended in decalin and tetradecane. At elevated temperatures, the particles interact like hard spheres. As the temperature is lowered, the suspensions gel. At the gel point, storage and loss moduli are power law functions of strain frequency providing evidence that cluster relaxation rates are much slower than the lowest strain frequency used. At volume fractions below the gel point (temperatures above the gel point), suspensions shear thin in much the same way as hard spheres. These studies suggest that the effect of volume fraction and attractive strength can be correlated when the normalized zero shear rate viscosity, η0/η0HS is written as a function of φ/φG, where η0HS is the high temperature (hard sphere), zero shear rate viscosity of a suspension at volume fraction φ, and φG is the volume fraction where, at the same strength of attraction, the suspensions gel. At φ/φG⩽0.95, η0/η0HS⩽5 suggesting suspension viscosities are weak function of attractions up to the gel point where relaxation times rapidly increase.
Lightweight Liquid Metal‐Elastomer Foam with Smart Multi‐Function
Authors: Yang Peng‐kun , Li Xin‐yang , Yang Xiao‐ying , Li Guan‐wu , Hu Zi‐juan , Huang Lu , Wu Ying‐peng
Published: September 2022

Lightweight metal‐polymer composited foam has drawn considerable attention in fields of wearable electronics, acoustic and electromagnetic shielding, automotive and aerospace manufacturing, owing to its unique advantages like electrical conductivity and mechanical properties. Herein, a facile strategy is studied for one‐step fabrication of multifunctional liquid metal (LM) permeated expancel microspheres foam (EMLM foam) with controllable shape and size. Specifically, the formation process and mechanism of bicontinuous structure with polymer and liquid metal are explored by real‐time monitoring and finite element simulation. Both experimental and simulating results confirmed a stable 3D metal interconnected network that can be constructed with lower limit of LM (3 vol.%). In addition, based on the unique features of reversible rigidity control, lightweight, electrical conductivity, and mechanical stability, the EMLM foam can exhibit intelligent performance in tunable acoustic, energy absorption, and thermal driving repair. Combined with EMLM foam's facile preparation process and versatility, it can provide the remarkable opportunity to develop the lightweight intelligent devices.
Wet‐Adhesive On‐Skin Sensors Based on Metal–Organic Frameworks for Wireless Monitoring of Metabolites in Sweat
Authors: Yang Xue , Yi Junqi , Wang Ting , Feng Yanan , Wang Jianwu , Yu Jing , Zhang Feilong , Jiang Zhi , Lv Zhisheng , Li Haicheng , Huang Tao , Si Duanhui , Wang Xiaoshi , Cao Rong , Chen Xiaodong
Published: September 2022

Metal–organic frameworks (MOFs) with well‐defined porous structures and tailored functionalities have been widely used in chemical sensing. However, the integration of MOFs with flexible electronic devices for wearable sensing is challenging because of their low electrical conductivity and fragile mechanical properties. Herein, a wearable sweat sensor for metabolite detection is presented by integrating an electrically conductive Ni‐MOF with a flexible nanocellulose substrate. The MOF‐based layered film sensor with inherent conductivity, highly porous structure, and active catalytic properties enables the selective and accurate detection of vitamin C and uric acid. More importantly, the lightweight sensor can conformably self‐adhere to sweaty skin and exhibits high water‐vapor permeability. Furthermore, a wireless epidermal nutrition tracking system for the in situ monitoring of the dynamics of sweat vitamin C is demonstrated, the results of which are comparable to those tested by high‐performance liquid chromatography. This study opens a new avenue for integrating MOFs as the active layer in wearable electronic devices and holds promise for the future development of high‐performance electronics with enhanced sensing, energy production, and catalytic capabilities through the implementation of multifunctional MOFs.
Spatial Band Separation in a Surface Doped Heterolayered Structure for Realizing Efficient Singlet Oxygen Generation
Authors: Jin Sen , Shao Wei , Luo Xiao , Wang Hui , Sun Xianshun , He Xin , Zhang Xiaodong , Xie Yi
Published: September 2022

Singlet oxygen (1O2) with electrical neutrality and long lifetime holds great promise in producing high‐added‐value chemicals via a selective oxidation reaction. However, photocatalytic 1O2 generation via the charge‐transfer mechanism still suffers from low efficiency due to the mismatched redox capacities and low concentration of photogenerated carriers in confined systems. Herein, by taking bismuth oxysilicate (Bi2O2SiO3) with alternating heterogeneous layered structure as a model, it is shown that iodine doping can facilitate the spatial redistributions of bands on alternated [Bi2O2] and [SiO3] layers, which can promote the separation and transfer of photogenerated charge carriers. Meanwhile, the band positions of Bi2O2SiO3 are optimized to match the redox potential of 1O2 generation. Benefiting from these features, iodine‐doped Bi2O2SiO3 exhibits efficient 1O2 generation with respect to its pristine counterpart, leading to promoted performance in the selective sulfide oxidation reaction. A new strategy is offered here for optimizing charge‐transfer‐mediated 1O2 generation.
Transition Metal Assisting Pre‐Lithiation Reduces the P/N Ratio to Balance the Energy Density and Cycle Life of Aqueous Batteries
Authors: Lv Tianshi , Zhu Xiangzhen , Lin Zejing , Suo Liumin
Published: September 2022

Aqueous Li‐ion batteries (ALIBs) are safe, environmentally friendly, and cost‐effective, promising for electric energy storage (EES). The high voltage ALIBs (HV‐ALIBs) supported by water‐in‐salt electrolytes are ideal for lowering the energy cost ($/Wh) of EES. However, HV‐ALIBs have been built with a high positive/negative capacity ratio (P/N ratio) to ensure their long‐term cycle life due to the irreversible Li consumption in the initial cycle induced by the solid electrolyte interface (SEI) formation and the parasitic reaction. Thus, the benefits of HV‐ALIBs in cost and energy density are mitigated inevitably. Generally, the feasible approach is adding per‐lithiation additives (PAs) to compensate for the capacity loss in the initial cycle. However, using PAs in ALIBs is challenging due to the high chemical activity of water. Here, a new strategy to achieve the pre‐lithiation by introducing manganese metal as a sacrificial PA for HV‐ALIBs that can provide over 900 mAh g−1 specific capacity without any adverse impact is proposed. The P/N ratio reduces to 1.02 by the LiMn2O4||TiO2 pouch cell using the sacrificial manganese PA. This results in a high initial energy density above 120 Wh kg−1 and outstanding cycle stability with a capacity retention of 80% after 400 cycles.
One‐Step Construction of a Polyporous and Zincophilic Interface for Stable Zinc Metal Anodes
Authors: Bie Zhe , Yang Qi , Cai Xinxin , Chen Ze , Jiao Zhaoyang , Zhu Junbo , Li Zhongfeng , Liu Jinzhang , Song Weixing , Zhi Chunyi
Published: September 2022

The development and application of rechargeable aqueous zinc‐ion batteries are seriously hindered by the problems of corrosion and dendrite growth on Zn metal anodes. Herein, a polyporous 3D zinc framework coupled with a zincophilic ZnSe overlayer (3D‐Zn@ZnSe) is synchronously obtained by one‐step electrochemical scanning, which precisely repairs intrinsic defects of the Zn foil surface and remodels the electrolyte/anode interface. The 3D‐Zn host formed by the pioneering electro‐oxidation significantly reduces the local current densities and facilitates adapting to the volume change during the plating/stripping. Meanwhile, the ZnSe overlayer obtained by electro‐deposition restrains the side reactions and promotes efficient desolvation, resulting in the acceleration of the deposition kinetics of Zn2+ on the zinc anode. As a result, the anodes present an enhanced cycling stability of zinc plating/stripping for over 2000 h with low overpotential, and the assembled 3D‐Zn@ZnSe||V2O5 cell retains 90.63% of its original capacity after 8500 cycles. The one‐step fabrication of polyporous interfaces with a zincophilic overlayer presents a promising strategy on improving the stability and reversibility of zinc anode for zinc‐based batteries.
A novel pathogenic ATP6V1B2 variant: Widening the genotypic spectrum of the epileptic neurodevelopmental phenotype
Authors: Veltra Danai , Kosma Konstantina , Papavasiliou Antigoni , Tilemis Faidon‐Nikolaos , Traeger‐Synodinos Joanne , Sofocleous Christalena
Published: September 2022

ATP6V1B2 pathogenic variants are linked with variable phenotypes, such as dominant deafness‐onychodystrophy syndrome (DDOD), autosomal dominant Zimmermann–Laband syndrome type 2 (ZLS2), and some cases of DOORS (deafness, onychodystrophy, osteodystrophy, intellectual disability [ID], and seizures). Epilepsy was first linked to ATP6V1B2, when the p.(Glu374Gln) missense variant was detected in a patient with ID and seizures, but without characteristic features of DDOD or ZLS2 syndromes. We herein report a novel pathogenic ATP6V1B2:p.Glu374Gly variant detected in an adult patient with ID and myoclonic‐atonic seizures. The (re)occurrence of different variants affecting the same highly conserved hydrophilic glutamic acid on position 374 of the V‐proton ATPase subunit B, indicates a potential novel pathogenic hotspot and a critical role for the specific residue in the development of epilepsy. ATP6V1B2 gene defects should be considered when analyzing patients with epilepsy, even in the absence of most cardinal features of DDOD, DOORS, or ZLS such as deafness, onychodystrophy, and osteodystrophy.
Variation in macroevolutionary dynamics among extant primates
Authors: Scott Jeremiah E.
Published: September 2022

Objectives

This study examines how speciation and extinction rates vary across primates, with a focus on the recent macroevolutionary dynamics that have shaped extant primate biodiversity.

Materials and methods

Lineage‐specific macroevolutionary rates were estimated for each tip in a tree containing 307 species using a hidden‐state likelihood model. Differences in tip rates among major clades were evaluated using phylogenetic ANOVA. Differences among diurnal, nocturnal, and cathemeral lineages were also evaluated, based on previous work indicating that activity pattern influences primate diversification.

Results

Rate variation in extant primates is low within clades and high between clades. As in previous studies, cercopithecoids stand out in having high net diversification rates, driven by high speciation rates and very low extinction rates. Platyrrhines combine high speciation and high extinction rates, giving them high rates of lineage turnover. Strepsirrhines and tarsiids have low rates of speciation, extinction, turnover, and net diversification. Hominoids are intermediate between platyrrhines and the strepsirrhine‐tarsiid group, and there is evidence for differentiation between hominids and hylobatids. Diurnal lineages have significantly higher speciation rates than nocturnal lineages.

Conclusions

Recent anthropoid macroevolution has been characterized by marked variation in diversification dynamics among clades. Strepsirrhines and tarsiids are more uniform, despite divergent evolutionary and biogeographic histories. Higher speciation rates in diurnal lineages may be driven by greater ecological opportunity or reliance on visual signals for mate recognition. However, the differences among anthropoids indicate that factors other than activity pattern (e.g., clade competition, historical contingency) have had a more influential role in shaping recent primate diversification.
Engineering Enzyme Substrate Scope Complementarity for Promiscuous Cascade Synthesis of 1,2‐Amino Alcohols
Authors: McDonald Allwin D. , Bruffy Samantha K. , Kasat Aadhishre T. , Buller Andrew R.
Published: September 2022

Biocatalytic cascades are uniquely powerful for the efficient, asymmetric synthesis of bioactive compounds. However, high substrate specificity can hinder the scope of biocatalytic cascades because the constituent enzymes may have non‐complementary activity. In this study, we implemented a substrate multiplexed screening (SUMS) based directed evolution approach to improve the substrate scope overlap between a transaldolase (ObiH) and a decarboxylase for the production of chiral 1,2‐amino alcohols. To generate a promiscuous cascade, we engineered a tryptophan decarboxylase to act efficiently on β‐OH amino acids while avoiding activity onl‐threonine, which is needed for ObiH activity. We leveraged this exquisite selectivity with matched substrate scope to produce a variety of enantiopure 1,2‐amino alcohols in a one‐pot cascade from aldehydes or styrene oxides. This demonstration shows how SUMS can be used to guide the development of promiscuous, C−C bond forming cascades.
Cetyltrimethylammonium bromide decorated MXene/polyimide nanocomposites with enhanced dielectric properties, thermostability, and moisture resistance
Authors: Cao Xianwu , Lu Chonghao , Zhao Wanjing , Tong Yizhang , He Guangjian , Zou Xinliang , Feng Yanhong , Yang Zhitao
Published: September 2022

Under extreme conditions, the polymer dielectric materials are expected to have good dielectric properties and heat resistance. Polyimide (PI) has high service temperature (>250°C) and low dielectric loss, but its low dielectric constant limits its further application. The addition of MXene can significantly improve the dielectric constant of PI, but the poor compatibility between MXene and weak polar matrix leads to Bénard‐Marangoni (BM) instability in the process of thermal imidization. This issue can be solved by the surface modification of MXene. Therefore, in this work, a new cetyltrimethylammonium bromide (CTAB) decorated MXene/PI nanocomposite film was prepared by in‐situ polymerization. With the addition of 7 wt% MXene@CTAB, the PI nanocomposite shows improved dielectric constant (k = 7.8 at 100 Hz), which is 2.4 times that of pure PI due to the formation of micro‐capacitors structure and Maxwell‐Wagner‐Sillars (MWS) interfacial polarization. Its dielectric loss keeps at an ultra‐low level (0.027 at 100 Hz) while that of 7 wt% MXene/PI nanocomposite is 3.027. It is owing that CTAB inhibits the agglomeration of MXene. In addition, MXene@CTAB/PI composites have excellent thermal stability, good hydrophobicity, and low water absorption. The above properties ensure MXene@CTAB/PI composites wide application in various extreme situations.
Molecularly Imprinted Electrochemical Sensor Based on Nitrogen‐doped Molybdenum Carbide Nanosphere for Trace Analysis of Resveratrol
Authors: Lu Huan , An Jiangxue , Huang Yan , Cui Hanyue , Yang Jing , Li Li , Ding Yaping
Published: September 2022

A novel molecularly imprinted electrochemical sensor based on nitrogen‐doped molybdenum carbide(N−Mo2C) nanosphere was fabricated for trace analysis of resveratrol in this work. N−Mo2C with large specific surface area and good electrical conductivity was introduced to construct a sensitive imprinting platform. Molecularly imprinted polymer film was prepared through a simple electropolymerization method using resveratrol as the template molecule and o‐phenylenediamine as the functional monomer. The sensor shows great analytical performance in the concentration range of 10−9 mol L−1 to 10−4 mol L−1and the detection limit is as low as 4.37×10−10 mol L−1. The sensor also has the advantages of good selectivity, reproducibility and stability, which opens a new way for the application of molecularly imprinted electrochemical sensors in the field ofbiomedicine detection.
Miscellaneous radio galaxies from LOFAR survey
Authors: Sasmal Tapan K. , Bera Soumen , Mondal Soumen
Published: September 2022

Our work aims to identify the miscellaneous radio galaxies (MRGs) using the LOFAR Two‐meter Sky Survey First Data Release (LoTSS DR1) at 144 MHz. The miscellaneous radio sources are very rare because of their peculiar morphological radio structure, which does not match with the known classes of radio sources. We find only four such MRGs by manually examining 18,500 samples. The peculiar morphology is not found in other radio frequencies 1400, 150, and 325 MHz. We estimate different physical parameters like spectral index, radio luminosity, and radio power of these sources. Among the four MRGs, J1428+4556 has the highest linear size of 3.972 Mpc and can be considered a giant radio galaxy. We also try to present the known galaxy cluster association with these MRGs. We find that the MRGs are associated with at least one galaxy cluster within 1 Mpc radius. The basic parameters such as mass, radius, and richness of the clusters are also noted.
Investigating the impact of adopting Python and C languages for introductory engineering programming courses
Authors: Balreira Dennis G. , Silveira Thiago L. T. da , Wickboldt Juliano A.
Published: September 2022

Programming is one of the most fundamental initial skills for engineering students. Institutions that offer engineering courses have the challenge of deciding how to deliver this subject since it requires unique thinking from students. This paper addresses the impact of adopting C and Python programming languages in introductory programming courses for engineering students. A case study was conducted in the university's introductory programming course, analyzing student data. This approach divides the students into two groups according to the programming language: C and Python. Data were gathered and analyzed about their learning experiences through questionnaires, assignment scores, and students' questions posted in the class online forums. The experiment was repeated in two consecutive semesters. The main results favor Python regarding learning confidence, motivation, and general programming design decisions while favoring C for the easiness of learning data structures. This study may be helpful for institutions considering designing a new introductory programming course or redesigning existing ones.
High Selective Direct Synthesis of H2O2 over Pd1@γ‐Al2O3 Single‐Atom Catalyst
Authors: Wang Xuning , Xu Haoxiang , Luo Yibin , Cheng Daojian
Published: September 2022

Pd‐based catalysts are essential for direct synthesis of H2O2 from H2 and O2, which still need further improvement of the activity and selectivity by engineering the status of Pd active species. In this work, isolated Pd atoms anchored on Al vacancy of the γ‐Al2O3(100) surface (Pd1@γ‐Al2O3(100)) are proposed to act as a heterogeneous catalyst for direct synthesis of H2O2 from first‐principles theoretical study and micro‐kinetic analysis. The thermodynamic stability and whole catalytic mechanism for conversion of O2 to H2O2 on Pd1@γ‐Al2O3(100) was studied. It is found that the high selectivity toward H2O2 of Pd1@γ‐Al2O3(100) is attributed to the high oxidation state of isolated Pd active sites with high stability against atom‐aggregation, derived from the strong electronic metal‐support interaction. The formation of 3+ cation state of isolated Pd atoms activates adsorbed oxygen molecule for hydrogenation and simnutaously restrains the formation of intermediate toward by‐product, compared with traditional bulk Pd catalyst in the metallic state. This work provides theoretical insights into the feasibility of atom‐level dispersion Pd to catalyze direct synthesis of H2O2 and guidance for its future development.
Metal‐Catalyzed Hydrophosphination
Authors: Novas Bryan T. , Waterman Rory
Published: September 2022

Organophosphines have garnered attention from many avenues ranging from agriculture to fine chemicals. One‐time use of phosphate resources has made sustainable use of phosphorus overall imperative. Hydrophosphination serves as an efficient method to selectively prepare P−C bonds, furnishing a range of phosphorus‐containing molecules while maximizing the efficient use of phosphorus. Since the first report in 1958, a wide array of catalysts have appeared for hydrophosphination, a reaction that is spontaneous in some instances. This review presents a representative view of the literature based on known catalysts through mid‐2022, highlighting extensions to unique substrates and advances in selectivity. While several excellent reviews have appeared for aspects of this transformation, this review is meant as a comprehensive guide to reported catalysts.
Prediction of bio‐oil yield during pyrolysis of lignocellulosic biomass using machine learning algorithms
Authors: Mathur Jayant , Baruah Bhargav , Tiwari Pankaj
Published: September 2022

This work aims to implement and use machine learning algorithms to predict the yield of bio‐oil during the pyrolysis of lignocellulosic biomass based on the physicochemical properties and composition of the biomass feed and pyrolysis conditions. The biomass pyrolysis process is influenced by different process parameters, such as pyrolysis temperature, heating rate, composition of biomass, and purge gas flow rate. The inter‐relation between the yield of different pyrolysis products and process parameters can be well predicted by using different machine learning algorithms. In this study, different machine learning algorithms, namely, multi‐linear regression, gradient boosting, random forest, and decision tree, have been trained on the dataset and the models are compared to identify the optimum method for the determination of bio‐oil yield prediction model. Analysis of the results showed the gradient boosting method to possess a regression score of 0.97 and 0.89 for the training and testing sets with root‐mean‐squared error (RMSE) values of 1.19 and 2.39, respectively, and overcome the problem of overfitting. Therefore, the present study provides an approach to train a generalized machine learning model, which can be employed on large datasets while avoiding the error of overfitting.
Chemistry creates transparency: Will future window panes be wood‐based?
Authors: Maaß Mona Christin , Schüler Tom , Waitz Thomas
Published: September 2022

Holz hat gegenüber vielen anderen Materialien zahlreiche ökologische Vorteile und wird deshalb immer vielfältiger verwendet, z. B. für die Herstellung von Fahrradrahmen. In Zukunft könnten auch Fensterscheiben daraus gefertigt werden, weil es Wissenschaftler:innen vor Kurzem gelungen ist, transparentes Holz herzustellen. Dies hätte auch ökonomische Vorteile, da transparentes Holz besser wärmeisolierend als Glas ist und für Raumwärme laut Bundesverband der Energie‐ und Wasserwirtschaft immerhin mehr als ein Viertel der in Deutschland insgesamt benötigten Energie aufgewendet werden muss und außerdem die Glasherstellung vergleichsweise energieaufwendig ist. In diesem Artikel werden die fachlichen Grundlagen zur Herstellung von transparentem Holz beschrieben. Darüber hinaus werden Experimente zur Umsetzung des Verfahrens in der Schule und zu den optischen sowie thermischen Eigenschaften des transparenten Holzes präsentiert. Abschließend werden didaktische Perspektiven für den Chemieunterricht aufgezeigt.
Retinal neuroblast migration and ganglion cell layer organization require the cytoskeletal‐interacting protein Mllt11
Authors: Blommers Marley , Stanton‐Turcotte Danielle , Iulianella Angelo
Published: September 2022

Background

The vertebrate retina is an organized laminar structure comprised of distinct cell types populating three nuclear layers. During development, each retinal cell type follows a stereotypical temporal order of genesis, differentiation, and migration, giving rise to its stratified organization. Once born, the precise positioning of cells along the apico‐basal (radial) axis of the retina is critical for subsequent connections to form, relying on highly orchestrated migratory processes. While these processes are critical for visual function to arise, the regulators of cellular migration and retinal lamination remain largely unexplored.

Results

We report a role for a microtubule‐interacting protein, Mllt11 (myeloid/lymphoid or mixed‐lineage leukemia; translocated to chromosome 11/All1 fused gene from chromosome 1q) in mammalian retinal cell migration during retinogenesis. We show that Mllt11 loss‐of‐function in mouse retinal neuroblasts affected the migration of ganglion and amacrine cells into the ganglion cell layer and led to their aberrant accumulation in the inner nuclear and plexiform layers.

Conclusions

We demonstrate a role for Mllt11 in neuroblast migration and formation of the ganglion cell layer of the retina.