bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of dolphin (Tursiops truncatus) auditory sensitivity and hearing loss using jawphones
Authors: Brill Randall L. , Moore Patrick W. B. , Dankiewicz Lois A.
Published: July 2002

Devices known as jawphones have previously been used to measure interaural time and intensity discrimination in dolphins. This study introduces their use for measuring hearing sensitivity in dolphins. Auditory thresholds were measured behaviorally against natural background noise for two bottlenose dolphins (Tursiops truncatus); a 14-year-old female and a 33-year-old male. Stimuli were delivered to each ear independently by placing jawphones directly over the pan bone of the dolphin’s lower jaw, the assumed site of best reception. The shape of the female dolphin’s auditory functions, including comparison measurements made in the free field, favorably matches that of the accepted standard audiogram for the species. Thresholds previously measured for the male dolphin at 26 years of age indicated a sensitivity difference between the ears of 2–3 dB between 4–10 kHz, which was considered unremarkable at the time. Thresholds for the male dolphin reported in this study suggest a high-frequency loss compared to the standard audiogram. Both of the male’s ears have lost sensitivity to frequencies above 55 kHz and the right ear is 16–33 dB less sensitive than the left ear over the 10–40 kHz range, suggesting that males of the species may lose sensitivity as a function of age. The results of this study support the use of jawphones for the measurement of dolphin auditory sensitivity.
A model and experimental study of fiber orientation effects on shear wave propagation through composite laminates
Authors: Fei Dong , Hsu David K.
Published: July 2002

The strong elastic anisotropy of the discrete unidirectional plies in a composite laminate interacts sensitively with the polarization direction of a shear ultrasonic wave propagating in the thickness direction. The transmitted shear wave can therefore be used to detect errors in the ply orientation and stacking sequence of a laminate. The sensitivity is particularly high when the polarization directions of the shear wave transmitter and receiver are orthogonal to each other. To understand the interaction between normal-incident shear waves and ply orientations in a laminate, a complete analytical model was developed using local and global transfer matrices. The model predicted the transmitted signal amplitude as a function of polarization angle of the transmitter and time (or frequency) for a given laminate and input signal. To alleviate the experimental problems associated with shear wave coupling, electromagnetic acoustic transducers (EMATs) and metal delay lines were used in the angular scan of the transmitted signal. The EMAT system had the added advantage of being applicable to uncured composite laminates. Experiments were performed on both cured and uncured laminates with common layups for model verification. The sensitivity of the measured shear wave signals to fiber misorientation and stacking sequence errors was also demonstrated.
Neural contributions to the perstimulus compound action potential: Implications for measuring the growth of the auditory nerve spike count as a function of stimulus intensity
Authors: Doucet John R. , Relkin Evan M.
Published: July 2002

The perstimulus compound action potential (PCAP), unlike the more familiar compound action potential (CAP), can be recorded in response to asynchronous as well as synchronous auditory nerve activity. When all neurons contribute equally to the PCAP, the area under the PCAP (the PCAP area) is proportional to the number of action potentials fired by auditory nerve neurons (the auditory nerve spike count). The auditory nerve spike count is one proposed code for stimulus intensity, and our goal is to use the PCAP to test this hypothesis. In this study, two independent tests were developed to measure the contributions of neurons to the PCAP as a function of their characteristic frequency (CF). The test results were verified using a model of the auditory periphery designed to calculate the auditory nerve spike count as a function of pure tone intensity and frequency. In nearly all experiments, neurons having CFs that span contiguous three or four octave bands contribute equally to the PCAP. For pure tones that stimulate only those neurons contributing equally to the PCAP, the PCAP area grows over intensity ranges frequently exceeding 80 dB, and in one case equaling 108 dB. These results demonstrate that the auditory nerve spike count, at least for pure tones, is capable of encoding changes in stimulus intensity over the entire dynamic range of the auditory system.
Scaling perceived distance of virtual sound sources
Authors: Zahorik Pavel
Published: July 2002

Magnitude estimation and paired-comparison scaling methods were applied to the problem of measuring perceived auditory distance. Stimuli consisted of binaural recordings made in a reverberant hallway at distances of 1, 2, 4, 8, 16, 32, and 64 ft. A loudspeaker produced broadband noise burst, 100 ms in duration, served as the distal stimulus. Insert-style microphones were placed in the ears of a single individual, with measurements made from two directions, extending in distance either from the individual’s front or left side. Construction of virtual sound source stimuli in this fashion insured that the stimulation reaching the listener was naturalistic and therefore possessed the acoustic cues thought to be important in the real-world perception of auditory distance. Five listeners were presented these stimuli in several variants of both the magnitude estimation and paired-comparison paradigms. Though relatively large individual variability exists, the resulting scales are all compressed when compared to the corresponding scale of physical distance. The amount of compression is shown to be approximately constant across scaling method, thereby providing validation for each method’s measurement of a similar underlying psychological process. [Work supported by NASA.]
The development of speech adaptation to an artificial palate
Authors: Baum Shari R. , McFarland David H.
Published: July 2002

An investigation of adaptation to palatal modification in [s] production was conducted using acoustic and perceptual analyses. The experiment assessed whether adaptation would occur subsequent to a brief period of intensive, target-specific practice. Productions of [sa] were elicited at five time intervals, 15 min apart, with an artificial palate in place. Between measurement intervals, subjects read [s]-laden passages to promote adaptation. Results revealed improvement in both acoustic and perceptual measures at the final time interval relative to the initial measurement period. Interestingly, the data also suggested changes to normal (unperturbed) articulation patterns during the same interval. Results are discussed in relation to the development of speech adaptation to a structural modification of the oral cavity.
Latency of MEG M100 response indexes first formant frequency
Authors: Govindarajan Krishna K. , Phillips Colin , Poeppel David , Roberts Timothy P. L. , Marantz Alec
Published: July 2002

Magnetoencephalography recordings from the auditory cortex of subjects listening to synthetic vowels show a close correlation between the timing of the evoked M100 response and the first formant frequency (F1). These results are consistent with evoked magnetic field latencies elicited by tone stimuli, which show 100 to 300-Hz tones associated with latencies up to 30 ms longer than 500 to 3000-Hz tones. In experiment 1, three-formant vowels /u,a,i/ were presented at two fundamental frequencies (F0=100 Hz, 200 Hz). The M100 latency was a function of the vowel identity and not F0: M100 was significantly shorter for /a/ than /u/, consistent with the spectral center of gravity being at a higher frequency for /a/. In experiment 2, single-formant vowels (/u/:F1=330 Hz, /a/:F1=720 Hz) were covaried with two F0 values. M100 latencies were shorter for /a/ (high F1) than for /u/ (low F1), at both fundamentals. In experiment 3, subjects listened to pure-tone complexes with frequencies and amplitudes matching the F0 and F1 energy peaks of the stimuli in experiment 2. M100 latencies showed the same pattern: latency covaried with the energy peak corresponding to F1, suggesting that the sensitivity to the energy in the F1 range is not speech-specific. Finally, an experiment involving two-formant, amplitude-varying vowels will be presented.
Auditory perception following hair cell regeneration in European starling (Sturnus vulgaris): Frequency and temporal resolution
Authors: Marean G. Cameron , Burt John M. , Beecher Michael D. , Rubel Edwin W
Published: July 2002

Behavioral detection thresholds, auditory filter widths, and temporal modulation transfer functions were obtained from four starlings before, during, and after 11 days of subcutaneous injections of kanamycin, an aminoglycoside antibiotic. Birds were operantly conditioned to respond to pure tones and amplitude modulated noises ranging in frequency from 0.25 to 7 kHz using adaptive staircase procedures and were tested daily for 92 days after the first injection of aminoglycoside. All birds had threshold shifts of at least −60 dB at frequencies above 4 kHz. Lower frequencies were affected in some birds, although none of the birds had hearing loss below 3 kHz. All four birds had wider auditory filters at 5 kHz immediately after the aminoglycoside series. Any changes in frequency resolution at frequencies below 5 kHz were slight, transitory, and rarely observed. Two of the four birds had permanently wider auditory filters at 5 kHz. Temporal modulation transfer functions were briefly affected in two birds during the time of greatest threshold shift. Recovery of detection thresholds began soon after the injections ceased and continued for approximately 60 days. Recovery in frequency resolution lagged behind auditory threshold by about 10 days. Normal temporal resolution was observed in the context of impaired intensity and frequency resolution. Changes in auditory threshold and frequency resolution were closely associated for all birds at 5 kHz, but were correlated with statistical significance in only two birds. Scanning electron microscopy was performed on all four birds after 90 days of recovery and confirmed that the extent of initial damage was consistent with the pattern of observed hearing loss.
Masking with interaurally delayed stimuli: The use of “internal” delays in binaural detection
Authors: van der Heijden Marcel , Trahiotis Constantine
Published: July 2002

Detectability of 500-Hz tones was measured in the presence of broadband masking noise using three types of binaural conditions. In the first, the masker was presented diotically and the tone was interaurally delayed. In the second, the masker was interaurally delayed and the 500-Hz tone was presented either in phase (S0) or out of phase (Sπ). In the third, the masker consisted of the sum of two independent noises having interaural delays of equal magnitude and opposite sign. The signal was, once more, presented either in phase (S0) or out of phase (Sπ). Comparisons among the data and quantitative analyses assuming the use of compensatory “internal delays” suggested that internal delays are operative and compensate accurately for external delays of up to approximately 750 μs. The analyses also indicated that larger internal delays (i.e., up to 2 to 3 ms) are probably also operative. However, performance using such large internal delays appears to be degraded in accord with the hypothesis that their application introduces “noise” in the internal representation of the stimuli.
Overview of the hydroacoustic monitoring system for the Comprehensive Nuclear-Test-Ban Treaty
Authors: Lawrence Martin W.
Published: July 2002

A global hydroacoustic monitoring system is being implemented for use in verification of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). This system will provide hydroacoustic monitoring of all the world’s oceans for 24 h a day, every day of the year, into the indefinite future. This unique resource will utilize two types of station. One type will be based on a hydrophone at the SOFAR axis depth, cabled back to shore. The other will be based on a seismometer on a small island using detection of the T-phase signal. This latter station relies on a signal which has propagated predominantly through the ocean, but has been converted to seismic energy at the margin of the island. This new application of hydroacoustics highlights a number of scientific questions which have not been adequately addressed. Progress in implementation of this network will be described.
Nonsense-syllable recognition in noise using monaural and binaural listening strategies
Authors: Arsenault Michael D. , Punch Jerry L.
Published: July 2002

Using a binaurally equipped KEMAR manikin, syllables of the CUNY Nonsense Syllable Test were recorded in sound field at 0-degree azimuth against a background of cafeteria noise at 270-degrees azimuth, at several signal-to-noise (S/N) ratios. The combination of inputs recorded at each ear was delivered to ten normal-hearing (NH) and eight sensorineurally hearing-impaired (HI) listeners through insert earphones to produce five experimental listening conditions: (1) binaural head shadow (HS), in which ear presentation was analogous to the original stimulus recording, (2) binaural favorable (BF), in which the noise-shadowed (right-ear) recording was presented to both ears, (3) monaural favorable (MF), in which the noise-shadowed recording was presented only to the right ear, (4) monaural unfavorable (MU), in which the noise-unshadowed (left ear) recording was presented only to the left ear, and (5) simulated monaural aided (SMA), in which the noise-shadowed recording was presented to the right ear and the noise-unshadowed recording—attenuated by 20 dB relative to the HS condition—was presented to the left ear. All main effects (subject type, listening condition, and S/N ratio) were statistically significant. Normal listeners showed 3.3- and 3.2-dB advantages, respectively, due to head-shadow and binaural squelch, over hearing-impaired listeners. Some hearing-impaired listeners performed better under the SMA or BF conditions than under the HS condition. Potential digital signal processing strategies designed to optimize speech understanding under binaurally aided listening conditions are discussed.
Higher-order harmonics of limited diffraction Bessel beams
Authors: Ding Desheng , Lu Jian-yu
Published: July 2002

We investigate theoretically the nonlinear propagation of the limited diffraction Bessel beam in nonlinear media, under the successive approximation of the KZK equation. The result shows that the nth-order harmonic of the Bessel beam, like its fundamental component, is radially limited diffracting, and that the main beamwidth of the nth-order harmonic is exactly 1/n times that of the fundamental.
Velocity Profiles of a Non-Newtonian Fluid in Helical Flow
Authors: Rea David R. , Schowalter W. R.
Published: July 2002

Flow behavior of a 3% solution of polyisobutylene (Vistanex L-100) dissolved in decalin was studied in helical flow between concentric cylinders. Shear rate in the fluid ranged between approximately 30 and 200 sec−1. A flow visualization technique was developed which permitted quantitative measurement of velocity profiles in the helical flow field. Results indicate that the correspondence between helical flow and Poiseuille flow which is predicted for simple fluids in viscometric flows is in fact observed to a close approximation. One concludes that the spatial variation of flow direction which exists in helical flow does not have an important effect on the flow of polyisobutylene solution under conditions studied in these experiments, a result consistent with the theory of simple fluids. Velocity profile measurements at two axial positions in the helical flow field indicate that a fully developed velocity profile was readily established.
Measurement of biaxial extensional viscosity of wheat flour doughs
Authors: Huang Hsimin , Kokini Jozef L.
Published: July 2002

The biaxial extensional viscosity of wheat flour doughs was measured using the lubricated squeeze film apparatus. Two disks of different diameters, 80 and 57.2 mm, were employed, with an extension rate (0.011 s−1) which remained approximately constant with both disks. Using polydimethylsiloxane a steady state lasted from 40 to 70 s. Obtaining steady extensional flow with wheat doughs, on the other hand, necessitated 10 to 200 s depending on the magnitude of normal stresses which ranged from 5.018 to 0.361 KPa. Doughs with different protein contents (13.2%, 16.0%, and 18.8% based on 14%MB) showed different biaxial extensional viscosities. These increased with increasing protein content. At an extensional rate of 7.3×10−5 s−1 the biaxial extensional viscosity approached 6η; Trouton’s ratio (ratio of ηE to η) increases with extension rate. The differences between biaxial extensional viscosities and shear viscosities become more profound when viscosities are plotted versus stresses.
Modeling the dynamic properties of monodisperse linear polymer melts with wedge spectra
Authors: Frederick J. E. , Yeh S.-T. , McIntyre D. , Weidknecht M.
Published: July 2002

A mathematical model of the spectrum of relaxation times for molten linear monodisperse homopolymers has been developed which is the sum of two variations of the well-known wedge spectrum. Adjusting the six parameters of the model allows fitting the storage and loss moduli within experimental error over a range of 10–12 logarithmic decades of frequency which encompass the flow, plateau, transition, and glassy zones of viscoelastic behavior. Model parameters are easily determined with a desktop microcomputer using standard nonlinear least-squares fitting procedures. All six model parameters correspond directly to prominent features of experimental data. The plateau modulus, viscosity, steady-state shear compliance, and the frequency at which the storage and loss moduli cross can all be easily calculated from the model parameters. The limiting low- and high-frequency behaviors of the storage and loss moduli predicted by the model are consistent with experiment and with linear viscoelastic theory. For the transition zone, the model can closely mimic the dynamic behavior predicted by normal-coordinate molecular theories. The model is applied to experimental data for five narrow-distribution polystyrenes having molecular weights in the range of 60 000–540 000.
Segment connectivity, chain-length breathing, segmental stretch, and constraint release in reptation models. III. Shear flows
Authors: Hua Chi C. , Schieber Jay D. , Venerus D. C.
Published: July 2002

A previously proposed self-consistent reptation model that includes chain stretching, chain-length fluctuations, segment connectivity, and constraint release is used to predict transient and steady shearing flows. Quantitative comparisons are made with the concentrated solution data considered in the previous papers of the series. The model is able to capture quantitatively all features of experimental data considered, including overshoot in both shear and first normal stresses, the strain-rate dependence of the strain magnitude at maximum stress, the steady-state viscosity and first-normal-stress coefficient as functions of shear rate, the viscosity curves for different molecular weight, the transient and steady-state behavior of the extinction angle, and the stress relaxation in cessation of steady shear flow. The model can describe all aspects of the data very well except the magnitude of the overshoot in stress at high shear rates, where the model is somewhat over-predictive. A new method of analysis for shear stress decay following cessation of steady shear is proposed, based on the physics of the model.
Polymer disentanglement in steady-shear flow
Authors: Archer Lynden A.
Published: July 2002

A procedure is presented for investigating entanglement loss in polymer liquids during steady-shear flow. The method combines steady shearing with small-amplitude step strain measurements to determine the elastic modulus Ge of an entangled polymer network under steady-state flow conditions. In this study, superimposed step/steady-shear measurements are used to investigate entanglement loss in narrow molecular weight distribution polystyrene/diethyl phthalate solutions with variable entanglement density (9 < N/Ne < 58). For all materials studied, Ge decreases with increasing shear rate γ̇ over a wide range of rates. At high shear rates, an approximate scaling relation Ge(γ̇)∼γ̇−1/2 can be defined for all but the most weakly entangled polymer solution; for this material, a related scaling form Ge(γ̇)∼γ̇−1 correctly describes the experimental results. We also find that the ratio of limiting shear modulus Ge(0) to modulus at finite rate Ge(γ̇) is related to a molecular stretching functional 〈|E⋅u|〉 by Ge(0)/Ge(γ̇)≈〈|E⋅u|〉p, where p takes on values of 1 and 1/2, depending on whether contour length stretching is taken to be affine p=1, or nonaffine p=1/2. For the lowest molecular weight polymer investigated, the affine stretch result Ge(0)/Ge(γ̇)≈〈|E⋅u|〉 fairly describes the experimental results over the entire range of shear rate investigated. Other materials manifest a transition from an initially affine to a square-root nonaffine response Ge(0)/Ge(γ)≈〈|E⋅u|〉1/2, as the rate is increased. Implications of these results on polymer contour length dynamics are discussed.
X-ray powder diffraction study of ZnGa2Te4
Authors: Rashmi  , Dhawan U.
Published: July 2002

ZnGa2Te4 was found to crystallize in a defect tetrahedral structure with possible space group I4(82) with Z=2. Complete X-ray powder diffraction data were obtained and the unit cell parameters a and c and X-ray density were calculated. These were a=0.5930(1) nm, c=1.1859(3) nm, and Dx=5.7×103 kg/m3.
Development and Testing of an Electronic Health Record‐Integrated Patient‐Reported Outcome Application and Intervention to Improve Efficiency of Rheumatoid Arthritis Care
Authors: Solomon Daniel H. , Dalal Anuj K. , Landman Adam B. , Santacroce Leah , Altwies Hallie , Stratton Jackie , Rudin Robert S.
Published: September 2022

Objective

Many patients with rheumatoid arthritis (RA) have difficulty finding clinicians to treat them because of workforce shortages. We developed an app to address this problem by improving care efficiency. The app collects patient‐reported outcomes (PROs) and can be used to inform visit timing, potentially reducing the volume of low‐value visits. We describe the development process, intervention design, and planned study for testing the app.

Methods

We employed user‐centered design, interviewing patients and clinicians, to develop the app. To improve visit efficiency, symptom tracking logic alerts clinicians to PRO trends: worsening PROs generate alerts suggesting an earlier visit, and stable or improving PROs generate notifications that scheduled visits could be delayed. An interrupted time‐series analysis with a nonrandomized control population will allow assessment of the impact of the app on visit frequency.

Results

Patient interviews identified several of the following needs for effective app and intervention design: the importance of a simple user interface facilitating rapid answering of PROs, the availability of condensed summary information with links to more in‐depth answers to common questions regarding RA, and the need for clinicians to discuss the PRO data during visits with patients. Clinician interviews identified the following user needs: PRO data must be easy to view and use during the clinical workflow, and there should be reduced interval visits when PROs are trending worse. Some clinicians believed visits could be delayed for patients with stable PROs, whereas others raised concerns.

Conclusion

PRO apps may improve care efficiency in rheumatology. Formal evaluation of an integrated PRO RA app is forthcoming.
When the End Effector Is a Laser: A Review of Robotics in Laser Surgery
Authors: Lee Hun Chan , Pacheco Nicholas E. , Fichera Loris , Russo Sheila
Published: September 2022

Combining laser technology with robotic precision and accuracy promises to introduce significant advances in minimally invasive surgical interventions. Lasers have already become a widespread tool in numerous surgical applications. They are proposed as a replacement for traditional tools (i.e., scalpels and electrocautery devices) to minimize surgical trauma, decrease healing times, and reduce the risk of postoperative complications. Compared to other energy sources, laser energy is wavelength‐dependent, allowing for preferential energy absorption in specific tissue types. This potentially leads to minimizing damage to healthy tissue and increasing surgical outcomes control and quality. Merging robotic control with laser techniques can help physicians achieve more accurate laser aiming and pave the way to automatic control of laser–tissue interactions in closed loop. Herein, a review of the state‐of‐the‐art robotic systems for laser surgery is presented. The goals of this paper are to present recent contributions in advanced intelligent systems for robot‐assisted laser surgery, provide readers with a better understanding of laser optics and the physics of laser–tissue interactions, discuss clinical applications of lasers in surgery, and provide guidance for future systems design.
Vibration‐Assisted Charge Transport through Positively Charged Dimer Junctions
Authors: Zhu Xin , Wang Boyu , Xiong Wan , Zhou Shuyao , Qu Kai , Lü Jing‐Tao , Chen Hongliang , Jia Chuancheng , Guo Xuefeng
Published: September 2022

Intermolecular charge transport plays a vital role in the fields of electronics, as well as biochemical systems. Here, we design supramolecular dimer junctions and investigate the effects of charge state and energy level alignment on charge transport under nanoconfinement. Incoherent tunneling caused by thermally‐induced vibrations is enhanced in positively charged systems. The transition between coherent and incoherent tunneling is associated with specific molecular vibration modes. Positively charged systems with smaller torsional barriers and vibrational frequencies result in lower transition temperatures. Multiple thermal effects have a great impact on the conductance in the off‐resonant tunneling, while thermally‐induced vibron‐assisted tunneling contributes more to the transport in the resonant tunneling. These investigations offer a deep mechanism understanding of intermolecular charge transport and facilitate the development of practical functional molecular devices.
Unique Double Intramolecular and Intermolecular Exciton Coupling in Ethene‐Bridged aza‐BODIPY Dimers for High‐Efficiency Near‐Infrared Photothermal Conversion and Therapy
Authors: Guo Xing , Yang Jinming , Li Mao , Zhang Fan , Bu Weibin , Li Heng , Wu Qinghua , Yin Dengke , Jiao Lijuan , Hao Erhong
Published: September 2022

Spatial electronic communications of chromophores are both theoretically and practically fascinating. Despite intramolecular or intermolecular exciton coupling was observed in multichromophoric oligomers and J‐aggregates, respectively, it is unusual that they both occur in the same molecule. Herein, ethene‐bridged aza‐BODIPY dimers with intramolecular exciton splitting have been developed. By encapsulating the dimer into F‐127 polymer, J‐type aggregated nanoparticles were produced, which showed obvious intermolecular exciton coupling and dramatically redshifted absorption and emission peaks at 936 and 1003 nm, respectively. The fabricated nanoagents have high photothermal conversion ability (η=60.3 %) and are ultra‐photostable, leading to complete tumor ablation with 915 nm laser irradiation. This phototherapeutic nanoplatform through modulating both intra‐ and intermolecular exciton couplings is a valuable paradigm for developing photothermal agents for tumor treatment.
Quantifying the Influence of Covalent Metal‐Ligand Bonding on Differing Reactivity of Trivalent Uranium and Lanthanide Complexes
Authors: Fetrow Taylor V. , Zgrabik Joshua , Bhowmick Rina , Eckstrom Francesca D. , Crull George , Vlaisavljevich Bess , Daly Scott R.
Published: September 2022

Qualitative differences in the reactivity of trivalent lanthanide and actinide complexes have long been attributed to differences in covalent metal‐ligand bonding, but there are few examples where thermodynamic aspects of this relationship have been quantified, especially with U3+ and in the absence of competing variables. Here we report a series of dimeric phosphinodiboranate complexes with trivalent f‐metals that show how shorter‐than‐expected U−B distances indicative of increased covalency give rise to measurable differences in solution deoligomerization reactivity when compared to isostructural complexes with similarly sized lanthanides. These results, which are in excellent agreement with supporting DFT and QTAIM calculations, afford rare experimental evidence concerning the measured effect of variations in metal‐ligand covalency on the reactivity of trivalent uranium and lanthanide complexes.
From Inert to Catalytically Active Milling Media: Galvanostatic Coating for Direct Mechanocatalysis
Authors: Wohlgemuth Maximilian , Mayer Maike , Rappen Marisol , Schmidt Fabian , Saure Roman , Grätz Sven , Borchardt Lars
Published: September 2022

The inert milling balls, commonly utilized in mechanochemical reactions, were coated with a layer of Pd and utilized as catalyst in the direct mechanocatalytic Suzuki reaction. With high yields (>80 %), the milling balls can be recycled multiple times in the absence of any solvents, ligands, catalyst‐molecules and ‐powders, while utilizing as little as 0.8 mg of Pd per coated milling ball. The coating sequence, the support material, and the layer thickness were examined towards archiving high catalyst retention, low abrasion and high conversion. The approach was transferred to the coating of milling vessels revealing the interplay between catalytically available surface area and the mechanical energy impact in direct mechanocatalysis.
On the regularity and stability of the Mayer‐type convex optimal control problems
Authors: Djendel Khelifa , Zhang Haisen , Zhou Zhongcheng
Published: September 2022

This paper is devoted to sufficient condition for Strong Metric sub‐Regularity (SMsR for short) of the set‐valued mapping corresponding to the local description of Pontryagin maximum principle for the Mayer‐type optimal control problems with convexity condition of the Hamiltonian and functional. In particular, stability property of optimal control for the Mayer‐type problem has been established for the occasion of a polyhedral control set and entirely bang‐bang solution structure. Moreover, based on the sufficiency of SMsR and stability property of optimal control, we give the approximate errors of Euler discretization methods utilized to such problems.
Current Status of Formulations and Scalable Processes for Producing Sulfidic Solid‐State Batteries
Authors: Batzer Mattis , Heck Carina , Michalowski Peter , Kwade Arno
Published: September 2022

Solid‐state batteries possess the potential to combine increased energy densities, high voltages, as well as safe operation and therefore are considered the future technology for electrical energy storage. In particular, sulfides as solid electrolyte are promising candidates due to their high ionic conductivities and the possibility of a scalable production. This review aims to demonstrate ways to manufacture suspension‐based sulfidic solid‐state batteries both on a laboratory scale and on an industrial level, focusing on the assessment of current knowledge and its discussion from a process engineering point of view. In addition to the influence of process parameters during mechanochemical synthesis of the solid electrolyte, formulation strategies for electrodes and separators are presented. The process chain from dispersion to cell assembly is evaluated. Scale‐up technologies are considered in comparison to established techniques in the field of conventional lithium‐ion batteries with liquid electrolyte summarizing the current status of sulfidic solid‐state battery production.
Is One of the Least Coordinating Anions Suitable to Serve as Electrolyte Salt for Magnesium‐Ion Batteries?
Authors: Schmidt Alexei , Koger Hendrik , Barthélemy Antoine , Studer Gauthier , Esser Birgit , Krossing Ingo
Published: September 2022

Weakly coordinating anions (WCAs) are considered promising candidates for application as electrolytes in multivalent post‐lithium batteries. One strong candidate as electrolyte salt for Mg battery application is [Mg(L)x][Al(ORF)4]2 (L=MeCN (acetonitrile), DME (1,2‐dimethoxyethane); x=3, 6; RF=C(CF3)3) that contains [Al(ORF)4]− as one of the least coordinating WCAs known. Here we present a novel synthetic route, for which vibrational, NMR and XRD analyses show the formation of a clean, pristine electrolyte salt without the common contaminants found in published synthetic routes. The electrochemistry of this pristine and pure [Mg(DME)3][Al(ORF)4]2 electrolyte (0.2 m in DME) was investigated via cyclic voltammetry (CV). In contrast to previous publications using impure materials, the CV showed no sign for Mg deposition from the pristine electrolyte for all conditions tested. This also holds when including the additives LiCl, NaCl, MgCl2, Li[BH4] or a mixture of MgCl2/Mg[HMDS]2 (HMDS=hexamethyldisilazide) in THF. Quantum chemical calculations suggested the possibility of anion decomposition at the negative electrode, leading to an electronically insulating MgF2 layer (rutile structure) on all the electrode materials tested. This hypothesis was confirmed by an XPS investigation of electrodes exposed to the electrolytes containing the WCAs [Al(ORF)4]− and [Al(OC(H)(CF3)2)4]− at negative potentials, which only showed the presence of MgF2 for the [Al(ORF)4]− electrolyte, but not for the related [Al(OC(H)(CF3)2)4]− electrolyte (which allowed to deposit magnesium reversibly on the electrode).
Two‐Electron Tetrathiafulvalene Catholytes for Nonaqueous Redox Flow Batteries
Authors: Daub Nicolas , Hendriks Koen H. , Janssen René A. J.
Published: September 2022

Tetrathiafulvalene (TTF) exhibits two reversible oxidation steps and is used as a novel multi‐electron catholyte for nonaqueous organic redox flow batteries. To increase solubility in polar organic solvents, TTF derivatives with polar side chains are synthesized. 4‐Methoxymethyltetrathiafulvalene emerges as a promising two‐electron catholyte because it is a liquid at room temperature and miscible with acetonitrile. Bulk‐electrolysis experiments and UV‐vis‐NIR absorption spectroscopy reveal excellent cycling stability for the first and second electrochemical oxidations. In the doubly oxidized state, the TTF derivatives show a reversible about 1 % loss of the state of charge per day, due to extrinsic effects. In a symmetric redox flow battery, 4‐methoxymethyltetrathiafulvalene shows a volumetric capacity loss of only 0.2 % per cycle with a Coulombic efficiency (CE) of 99.6 %. In an asymmetric redox flow battery with a pyromellitic diimide as two‐electron anolyte, the capacity loss is 0.8 % per cycle, with CE>99 % in each cycle.
Applications of surface‐enhanced Raman spectroscopy based on portable Raman spectrometers: A review of recent developments
Authors: Wang Wei , Ma Pinyi , Song Daqian
Published: September 2022

Recently, the surface‐enhanced Raman spectroscopy (SERS) technique emerges as a potential promising analytical tool for rapid, sensitive, and selective detection which can provide unique information about the substances in the presence of plasmonic nanostructures via finger‐printing SERS spectra. The progress in nanostructure SERS substrates and portable Raman spectrometers will promote this novel detection technique to play an important role in the future rapid on‐site assay. In this review, we summarized the latest research on SERS detection technique combined based on nanostructure SERS‐active substrates with portable Raman spectrometers and their potential on‐site detection applications in environment pollutants, agricultural pollutants, biomedical analysis, and other newly emerging fields (focusing particularly on the last 5 years of research). The future perspective of SERS for on‐site analysis is also discussed.
Chitosan‐based nanoscale systems for doxorubicin delivery: Exploring biomedical application in cancer therapy
Authors: Ashrafizadeh Milad , Hushmandi Kiavash , Mirzaei Sepideh , Bokaie Saied , Bigham Ashkan , Makvandi Pooyan , Rabiee Navid , Thakur Vijay Kumar , Kumar Alan Prem , Sharifi Esmaeel , Varma Rajender S. , Aref Amir Reza , Wojnilowicz Marcin , Zarrabi Ali , Karimi‐Maleh Hassan , Voelcker Nicolas H. , Mostafavi Ebrahim , Orive Gorka
Published: September 2022

Green chemistry has been a growing multidisciplinary field in recent years showing great promise in biomedical applications, especially for cancer therapy. Chitosan (CS) is an abundant biopolymer derived from chitin and is present in insects and fungi. This polysaccharide has favorable characteristics, including biocompatibility, biodegradability, and ease of modification by enzymes and chemicals. CS‐based nanoparticles (CS‐NPs) have shown potential in the treatment of cancer and other diseases, affording targeted delivery and overcoming drug resistance. The current review emphasizes on the application of CS‐NPs for the delivery of a chemotherapeutic agent, doxorubicin (DOX), in cancer therapy as they promote internalization of DOX in cancer cells and prevent the activity of P‐glycoprotein (P‐gp) to reverse drug resistance. These nanoarchitectures can provide co‐delivery of DOX with antitumor agents such as curcumin and cisplatin to induce synergistic cancer therapy. Furthermore, co‐loading of DOX with siRNA, shRNA, and miRNA can suppress tumor progression and provide chemosensitivity. Various nanostructures, including lipid‐, carbon‐, polymeric‐ and metal‐based nanoparticles, are modifiable with CS for DOX delivery, while functionalization of CS‐NPs with ligands such as hyaluronic acid promotes selectivity toward tumor cells and prevents DOX resistance. The CS‐NPs demonstrate high encapsulation efficiency and due to protonation of amine groups of CS, pH‐sensitive release of DOX can occur. Furthermore, redox‐ and light‐responsive CS‐NPs have been prepared for DOX delivery in cancer treatment. Leveraging these characteristics and in view of the biocompatibility of CS‐NPs, we expect to soon see significant progress towards clinical translation.
Comprehensive association analysis of speech recognition thresholds after cisplatin‐based chemotherapy in survivors of adult‐onset cancer
Authors: Shahbazi Mohammad , Zhang Xindi , Dinh Paul C. , Sanchez Victoria A. , Trendowski Matthew R. , Shuey Megan M. , Nguyen Tessa ,   Regeneron Genetics Center, Feldman Darren R. , Vaughn David J. , Fung Chunkit , Kollmannsberger Christian , Martin Neil E. , Einhorn Lawrence H. , Cox Nancy J. , Frisina Robert D. , Travis Lois B. , Dolan Mary Eileen
Published: September 2022

Purpose

Deficits in speech understanding constitute one of the most severe consequences of hearing loss. Here we investigate the clinical and genetic risk factors for symmetric deterioration of speech recognition thresholds (SRT) among cancer survivors treated with cisplatin.

Methods

SRT was measured using spondaic words and calculating the mean of measurements for both ears with symmetric SRT values. For clinical associations, SRT‐based hearing disability (SHD) was defined as SRT≥15 dB hearing loss and clinical variables were derived from the study dataset. Genotyped blood samples were used for GWAS with rank‐based inverse normal transformed SRT values as the response variable. Age was used as a covariate in association analyses.

Results

SHD was inversely associated with self‐reported health (p = 0.004). Current smoking (p = 0.002), years of smoking (p = 0.02), BMI (p < 0.001), and peripheral motor neuropathy (p = 0.003) were positively associated with SHD, while physical activity was inversely associated with SHD (p = 0.005). In contrast, cumulative cisplatin dose, peripheral sensory neuropathy, hypertension, and hypercholesterolemia were not associated with SHD. Although no genetic variants had an association p value < 5 × 10−8, 22 genetic variants were suggestively associated (p < 10−5) with SRT deterioration. Three of the top variants in 10 respective linkage disequilibrium regions were either positioned within the coding sequence or were eQTLs for genes involved in neuronal development (ATE1, ENAH, and ZFHX3).

Conclusion

Current results improve our understanding of risk factors for SRT deterioration in cancer survivors. Higher BMI, lower physical activity, and smoking are associated with SHD. Larger samples would allow for expansion of the current findings on the genetic architecture of SRT.
Genomics‐Guided Efficient Identification of 2,5‐Diketopiperazine Derivatives from Actinobacteria
Authors: Liu Jing , Li Shu‐Ming
Published: September 2022

Secondary metabolites derived from microorganism constitute an important part of natural products. Mining of the microbial genomes revealed a large number of uncharacterized biosynthetic gene clusters, indicating their greater potential to synthetize specialized or secondary metabolites (SMs) than identified by classic fermentation and isolation approaches. Various bioinformatics tools have been developed to analyze and identify such gene clusters, thus accelerating significantly the mining process. Heterologous expression of an individual biosynthetic gene cluster has been proven as an efficient way to activate the genes and identify the encoded metabolites that cannot be detected under normal laboratory cultivation conditions. Herein, we describe a concept of genomics‐guided approach by performing genome mining and heterologous expression to uncover novel CDPS‐derived DKPs and functionally characterize novel tailoring enzymes embedded in the biosynthetic pathways. Recent works focused on the identification of the nucleobase‐related and dimeric DKPs are also presented.
Failure patterns after intravascular brachytherapy for in‐stent coronary restenosis
Authors: Wallner Kent , Kearney Kathleen E. , Kim Minsun , Tiwana Jasleen , Elison David , Kim Edward Y. , Parvathaneni Upendra , Lombardi William L. , Phillips Mark L. , Don Creighton
Published: September 2022

Introduction

One strategy to improve the effectiveness of intravascular brachytherapy (IVBT) is to study its failures. Previous investigations described mostly discrete, focal recurrences, typically at the proximal or distal edges of the irradiated segment after plain angioplasty or bare metal stents. We reviewed failure patterns of 30 unselected drug‐eluting stent (DES) patients who had follow‐up angiograms for recurrence within their IVBT‐treated vessel.

Methods

Records of 53 unselected IVBT patients treated between 2016 and 2021 were reviewed. Thirty of the 53 patients had at least one subsequent percutaneous intervention (PCI) for in‐stent restenosis (ISR) after IVBT. Angiographic findings of those 30 patients with ISR within their previously irradiated vessel are reported here.

Results

Of the 30 patients, 21 (70%) developed recurrent ISR within the irradiated segment. Six of the 21 patients who failed within the irradiated segment also experienced ISR proximal or distal to the irradiated segment. Only 15 patients (50%) failed exclusively within the irradiated segment. In nine patients (30%), restenosis occurred proximally and/or distally to the irradiated segment, but not inside of the irradiated segment itself.

Conclusions

We have shown here that 50% of failures after coronary IVBT for DES ISR occur exclusively within the irradiated segment. An additional 20% of patients had failure within and outside of the irradiated segment. These percentages suggest that a higher radiation dose might improve the long‐term patency rates, a conclusion that should be tempered by the lack of universal follow‐up.
Ventricular tachycardia triggered by the first dose of an adenoviral vector‐based COVID‐19 vaccine in an adult patient with congenital heart disease
Authors: Bassareo Pier Paolo , Mihali Klevis , Walsh Kevin Patrick
Published: September 2022

A unique adverse event of adenoviral COVID‐19 vaccine in an adult patient with congenital heart disease is reported.
Lastabtragende Klebungen für aussteifende Verglasungen mit Absturzsicherung
Authors: Giese-Hinz Johannes , Nicklisch Felix , Baitinger Mascha , Reichert Jasmin , Weller Bernhard
Published: September 2022

Lastabtragende Klebungen sind in der Lage, Dauer‐, Kurzzeit‐ und Stoßbelastungen zu übertragen. Sie ermöglichen neue und innovative Konstruktionen. Aufgrund des Alterungsverhaltens der geklebten Verbindung sind jedoch Umwelteinflüsse bei der Bemessung zu berücksichtigen. Dieser Beitrag zeigt die Entwicklung eines neuartigen Aussteifungselements aus Glas mit Absturzsicherung, bei dem Klebungen einen maßgeblichen Beitrag zum Abtrag der unterschiedlich lang einwirkenden Lasten leisten. Teil der Entwicklung ist ein experimentelles Testprogramm sowie eine numerische Simulation mit Volumenelementen und Feder. Das Ergebnis ist ein einsatzbereites geklebtes Aussteifungselement und dessen Bemessungskonzept.

Load‐bearing bonding for in‐plane loaded glass balustrades. Load‐bearing adhesives are capable of transmitting permanent, short‐term and impact loads. They enable new and innovative designs. However, due to the aging behaviour of the bonded joint, environmental influences have to be taken into account in the design. This article shows the development of a new type of stiffening balustrade which is in‐plane loaded and made of glass. Bonding makes a significant contribution to the transfer of loads acting over different periods of time. Part of the development is an experimental test program as well as a numerical simulation with solid elements and springs. The result is a ready‐to‐use bonded stiffening element and its design concept.
Synthesis of novel green phosphate pigments with phosphophyllite composition
Authors: Onoda Hiroaki , Kanemoto Rina
Published: September 2022

A new green pigment with the composition of phosphophyllite was synthesized using zinc oxide, iron oxalate, and phosphoric acid in a hydrothermal process. The effects of hydrothermal treatment temperature and time were investigated. In order to obtain pigments with a variety of colors, compounds with related compositions were also prepared. Further, samples were prepared with nitrogen bubbling to suppress the oxidation of iron. The composition of the fabricated samples was evaluated by X‐ray diffraction and infrared spectra. The color of the samples was evaluated by ultraviolet‐visible reflectance spectra and L*a*b* color space. The samples prepared in this study were a mixture of Zn2Fe(PO4)2•2H2O, the target compound, and iron oxalate, the raw material. The obtained samples were yellow to green in color. The condition that yielded the best green pigment was hydrothermal treatment at 180°C for 20 h with nitrogen bubbling.
Room‐Temperature‐Observable Interconversion Between Si(IV) and Si(II) via Reversible Intramolecular Insertion Into an Aromatic C−C Bond
Authors: Eisner Teresa , Kostenko Arseni , Hanusch Franziska , Inoue Shigeyoshi
Published: September 2022

An easily isolable silacycloheptatriene (silepin) 1 b was synthesized from the reaction of a N‐heterocyclic imino (IPrN) substituted tribromosilane IPrNSiBr3 with the sterically congested bis(trimethylsilyl)triisopropylsilyl silanide KSi(TMS)2Si(iPr)3 (BTTPS). In solution, the Si(IV) silepin 1 b is in a thermodynamic equilibrium with the acyclic Si(II) silylene 1 a. The relative concentration of the Si(II) or Si(IV) isomers can be controlled by temperature variation and observed by variable temperature NMR and UV/Vis spectroscopy. DFT calculations show a small reaction barrier for the Si(II)⇌Si(IV) interconversion and a small energy gap between the Si(II) and Si(IV) species. The reactivity of 1 a/b is demonstrated on a variety of small molecules.