bluuebunny/crossref_metadata_2025 huggingface dataset:
Frequency specificity of the human auditory brainstem and middle latency responses to brief tones. I. High-pass noise masking
Authors: Oates Peggy , Stapells David R.
Published: July 2002

This study investigated the frequency specificity of the auditory brainstem (ABR) and middle latency (MLR) responses to 500- and 2000-Hz brief tones using high-pass noise masking. Stimuli were linear- (2-1-2 cycles) and exact-Blackman- (5 cycles) gated tones presented at 80 dB peak-to-peak equivalent (ppe) SPL. Cochlear contributions to ABR wave V-V′ and MLR wave Na-Pa were assessed by the effects of high-pass noise masking on response amplitudes and latencies. The high-pass noise results demonstrate that the ABR and the MLR to the 80 dB ppe SPL brief tones show good frequency and place specificity. Changes in ABR or MLR amplitude and latency with high-pass noise masking did not occur as the masker cutoff was decreased from 2 to 3 octaves above the stimulus nominal frequency until it was within one-half octave of this frequency, below which amplitudes rapidly decreased (500- and 2000-Hz tones) and latencies increased (500-Hz tones). No significant differences existed in the frequency specificity of the ABR versus MLR, or in these evoked potentials to exact-Blackman- versus linear-gated tones.
Tempo and beat analysis of acoustic musical signals
Authors: Scheirer Eric D.
Published: July 2002

A method is presented for using a small number of bandpass filters and banks of parallel comb filters to analyze the tempo of, and extract the beat from, musical signals of arbitrary polyphonic complexity and containing arbitrary timbres. This analysis is performed causally, and can be used predictively to guess when beats will occur in the future. Results in a short validation experiment demonstrate that the performance of the algorithm is similar to the performance of human listeners in a variety of musical situations. Aspects of the algorithm are discussed in relation to previous high-level cognitive models of beat tracking.
Interrelation between proton transfer reactions and solvent structure studied by the ultrasonic absorption method
Authors: Kuramoto N. , Nishikawa S.
Published: July 2002

Ultrasonic absorption coefficients in aqueous solutions of methanol at 1.00, 2.00, 3.00, 4.00, and 6.00 mol dm−3 and in those of ethanol at 1.00, 2.00, 3.00, 4.00, 5.00, and 6.00 mol dm−3 have been measured in the frequency range from 0.8–220 MHz at 25.0 °C. No excess absorption has been observed in any of these solutions except in the 5.00 and 6.00 mol dm−3 ethanol solutions, for which a Debye-type single relaxational equation has been fitted. In order to see the effects of methanol and ethanol on the dynamic characteristics of aqueous amine solutions, the ultrasonic absorption measurements have been carried out in aqueous solutions of propylamine containing 1.00, 2.00, 3.00, 4.00, and 6.00 mol dm−3 methanol and 1.00, 2.00, 3.00, and 4.00 mol dm−3 ethanol. The excess absorption has been observed, and the frequency dependence of the ultrasonic absorption coefficients has been well described by the Debye-type single relaxational equation. The cause of the relaxation is due to a perturbation of equilibrium associated with a proton transfer reaction. The rate constants have been determined from hydroxide ion concentration dependence of the relaxation frequency, and the standard volume change of the reaction has been calculated from the reactant concentration dependence of maximum absorption per wavelength. It has been found that the addition of methanol causes the decrease in the diffusion controlled rate constant and the trend of the decrease is more remarkable in the concentration range from 3.00–6.00 mol dm−3. On the other hand, the rate constant in the solution with ethanol has decreased linearly with an increase in the ethanol concentration. The reverse rate constant and the volume change of the reaction have not been affected by the addition of the two alcohols. Using a theoretical equation for the diffusion controlled reaction, a diffusion coefficient of the hydroxide ion has been determined at various concentrations of the additives. These results are discussed in relation to the effects of methanol and ethanol on water structure.
Reactions to environmental noise in an ambient noise context in residential areas
Authors: Fields James M.
Published: July 2002

Direct reanalyses of over 57 000 interview responses to 35 noise sources in 20 social surveys and reviews of publications for over 12 000 additional responses to 16 noise sources in 13 social surveys show that residents’ reactions to an audible environmental noise (a target noise) are only slightly or not at all reduced by the presence of another noise source (ambient noise) in residential environments. The direct reanalyses account for type of noise source (aircraft, road traffic, railway, impulse noise), type of noise reaction question, type of activity disturbance, quality of noise data, type of regression analysis model (linear, logit, probit), two noise metrics (DNL, LAeq), and ten personal characteristics. Although there is considerable variation from survey to survey, the best direct estimate is that approximately a 20-dB increase in ambient noise exposure (95% confidence interval of 15–50 dB) has no more impact than approximately a 1-dB decrease in target noise exposure. Tabulations of 12 findings from laboratory studies in which subjects rated periods of multiple noise events also found that target noise annoyance is not consistently reduced by ambient noise.
Some aspects of the lateralization of echoed sound in man. I. The classical interaural-delay based precedence effect
Authors: Tollin Daniel J. , Henning G. Bruce
Published: July 2002

The precedence effect in two-click stimuli was investigated by measuring observers’ sensitivity to interaural time delays (ITDs) as a function of interclick interval (ICI). A two-interval two-alternative forced-choice discrimination paradigm was used in two stimulus configurations: type I, a dichotic click with a given ITD preceded a diotic click; and type II, a dichotic click followed a diotic click. Threshold ITDs were measured in each configuration for a finely sampled distribution of ICIs that ranged from 0.1 to 25.6 ms. Performance was characterized by the “threshold elevation factor” (TEF) which normalized each of the observers’ type I and type II ITD thresholds relative to their ITD threshold for a single dichotic click. The finer sampling of ICIs revealed two novel results: First, for two observers, sensitivity to ITD in the later arriving ITD (type II) oscillated in a consistent and systematic way with changes in ICI. Second, when the ICI reached 12.8 ms, ITD thresholds in the type I and type II configurations were equal but nearly a factor of 2 greater than for a single dichotic click. Some aspects of the data are consistent with the phenomenon of binaural adaptation.
Frequency discrimination in budgerigars (Melopsittacus undulatus): Effects of tone duration and tonal context
Authors: Dent Micheal L. , Dooling Robert J. , Pierce Alisa S.
Published: July 2002

Studies of frequency resolving power in budgerigars (Melopsittacus undulatus) have shown that this species has excellent discrimination abilities for both simple and complex sounds falling in the region of 2 to 4 kHz—the frequency range of their contact call. In four experiments, frequency discrimination by budgerigars of short tones similar to elements found in the contact call was examined. Frequency difference limens (FDLs) for simple pure tones at 2.86 kHz were constant for tone durations above 20 ms but higher for shorter tones. Budgerigars generally showed larger FDLs for shorter duration 1-, 2-, and 4-kHz pure tones. FDLs in budgerigars for 20-ms tones embedded in a sequence of six other tones were similar to FDLs measured for tones of the same frequency presented in isolation. Moreover, there was no effect of introducing trial-by-trial variation in the location of the frequency change in the seven-tone complexes for budgerigars, a condition for which humans showed a large decrement in performance. Taken together, these results suggest budgerigars possess enhanced spectral resolving power for short duration pure tones when they are embedded in contact call-like tonal patterns.
On operating deflection shapes of the violin body including in-plane motions
Authors: Runnemalm Anna , Molin Nils-Erik , Jansson Erik
Published: July 2002

Earlier investigations have assumed only “out-of-plane” vibrations of the plates of the violin. The violin body can, however, be described as a thin-walled, double-arched shell structure and as such it may very well elongate in one direction as it contracts in another. Therefore, at least two orthogonal vibration components have to be included to describe the vibrations. The operating deflection shapes (ODSs) of a good, professionally made and carefully selected violin were therefore measured in several directions by TV holography to determine both “in-plane” and out-of-plane vibration components of the ODSs. The observations were limited to the frequency range 400–600 Hz, as this interval includes two most-prominent resonance peaks of bridge mobility and sound radiation as well as a third poorly radiating resonance. These three peaks clearly showed orthogonal vibration components in the ODSs. The vibration behavior of the violin body, sectioned in the bridge plane, was interpreted as the vibrations of an “elliptical tube” with nodal diameters. The number of nodal diameters increases from two to three in the selected frequency range. The TV holography measurements were supported by electrodynamical point measurements of bridge mobility, of air volume resonances, and by reciprocity, of radiation properties. Furthermore, a fourth mode, the air mode, A1, is involved indirectly in the sound radiation via influence on the body vibrations.
Rheological behavior and stability of concentrated silica suspensions
Authors: Lee Jae-Dong , So Jae-Hyun , Yang Seung-Man
Published: July 2002

In the present article, the rheological behavior and phase stability of concentrated silica suspensions were investigated experimentally by examining the effects of particle size and temperature. The silica particles were stabilized by adsorption of a silane coupling agent, γ-methacryloxypropyl triethoxy silane (MPTES). The MPTES-coated silica particles behaved like hard spheres and exhibited the dispersion stability in tetrahydrofurfuryl alcohol which was used as a refractive-index matching solvent. For a monodisperse suspension, the limiting viscosities at high shear rates were correlated satisfactorily with the Krieger–Dougherty equation until the particle volume fraction φ reached 0.45 above which the limiting high-shear-rate viscosities did not exist. The highly concentrated monodisperse suspensions above φ=0.50 displayed the rapidly shear thinning viscosity at low shear rates and underwent the shear thickening at high shear rates. Specifically, the onset of shear thickening shifted to a higher shear rate either as temperature rose or as the suspension became stable. The dichroism from light passed in the flow-gradient direction probed the most effectively the order–disorder transition such as disappearance of hexagonally ordered layered structure and formation of particle clustering, which caused shear thickening at high shear rates. The abrupt change in dichroism caused by the breakdown of hexagonally layered structure occurred almost 1 decade before the onset of shear thickening. Finally, the bimodal suspensions prepared here possessed the reduced shear viscosity and stress in comparison with the monodisperse suspensions of identical volume fraction. The degree of the viscosity reduction became conspicuous for concentrated suspensions usually above φ=0.40.
Melt rheology of poly(lactic acid): Entanglement and chain architecture effects
Authors: Dorgan John R. , Williams Joshua S. , Lewis David N.
Published: July 2002

Poly(lactic acids) (PLAs) are a family of polyesters available via fermentation from renewable resources and are the subject of considerable recent commercial attention. In this study, the melt rheological properties of a family of poly(lactic acid) stars are investigated and compared to the properties of the linear material. For polymers made from a 98:2 ratio of the L to D enantiomeric monomers it is found that the entanglement molecular weight is in the range of 9000 g per mole (Me≈8700 g/mol) while the molecular weight for branch entanglement is inferred to be approximately 3500 g per mole (Mb≈34 600 g/mol). In addition, the zero shear viscosity of the linear material increases with the 4.6 power of molecular weight. These results may suggest that PLA is a semistiff polymer in accordance with other recent findings. The increase in zero shear viscosity for the branched materials is measured and quantified in terms of appropriate enhancement factors. Relaxation spectra show that the transition zone for the linear and branched materials are nearly indistinguishable, while the star polymers have greater contributions to the terminal regime. The effects of chain architecture on the flow activation are found to be modest, implying that small scale motions in PLA homopolymers largely control this phenomenon. Good agreement is found between the dynamic data and many aspects of the theory of star polymers, however, a dependence of the zero shear viscosity on the number of arms is observed.
Pterygium-Derived Artifact Simulating an Intraocular Tumor With Ultrawide-Field Imaging
Authors: Fang Danqi , Huang Zijing , Chen Weiqi , Huang Dingguo
Published: September 2022

This case report describes an uncommon artifact of ultrawide-field imaging derived from a large pterygium, which mimicked an intraocular tumor.
Detection of Nonglaucomatous Macula Findings With Ganglion Cell Analysis Printouts vs Full Macular Cube Scans
Authors: Yamane Maya , Ferreyra Henry , Xu Benjamin Y. , Weinreb Robert N. , Camp Andrew S.
Published: September 2022

Importance

Ganglion cell analysis (GCA) of ocular coherence tomography (OCT) imaging is routinely used to detect and monitor glaucomatous damage of the ganglion cell complex in the macula. The GCA printout provides qualitative and quantitative data about the macular ganglion cell–inner plexiform layer and a single B-scan of the retina through the fovea. However, the full macular cube scan, including all 128 B-scans, is available for review. The macular cube scan provides considerable information about nonglaucomatous ocular pathology that may be missed if clinicians review only the GCA printout.

Objective

To determine the frequency and type of nonglaucomatous macular findings that are observable in the full macular cube scan but not the GCA printout.

Design, Setting, and Participants

A retrospective cross-sectional analysis of GCA printouts and full macular cube scans to detect nonglaucomatous macular pathology at a tertiary care academic center. Consecutive patients undergoing ganglion cell complex imaging during routine glaucoma evaluations over a 1-week period in a multi-clinician glaucoma clinic.

Main Outcomes and Measures

The prevalence and type of nonglaucomatous macular pathology visible on the GCA printout or macular cube scan.

Results

Among 105 patients (mean (SD) age, 67 (15.46) years; 63 [60%] female and 42 [40%] male) 201 eyes were imaged (64 [31.7%] with suspected glaucoma, 126 [62.4%] with open-angle glaucoma, 6 [3.0%] with closed-angle glaucoma, and 6 [3.0%] with other glaucoma). GCA printouts and macular cube scans revealed nonglaucomatous macular pathology in 65 eyes (32.2%). Of these, 25 eyes (38.5%) included findings that were not visible on the GCA printout. Of the cases not visible on the printout, 16 eyes (64.0% ) included macular pathology that required further evaluation.

Conclusions and Relevance

The findings indicate that nonglaucomatous macular pathology may be missed based on GCA printouts alone. While it may be beneficial to review the full macular cube to detect potentially vision-threatening disease and ensure proper patient care, this study cannot determine if this missed pathology affects clinical outcomes.
Integration of Screen Printed Piezoelectric Sensors for Force Impact Sensing in Smart Multifunctional Glass Applications
Authors: Andersson Ersman Peter , Eriksson Jerry , Jakonis Darius , Pantzare Sandra , Åhlin Jessica , Strandberg Jan , Sundin Stefan , Toss Henrik , Ahrentorp Fredrik , Daoud Kaies , Jonasson Christian , Svensson Henrik , Gregard Greger , Näslund Ulf , Johansson Christer
Published: September 2022

Screen printed piezoelectric polyvinylidene fluoride–trifluoro ethylene (PVDF–TrFE)‐based sensors laminated between glass panes in the temperature range 80–110 °C are presented. No degradation of the piezoelectric signals is observed for the sensors laminated at 110 °C, despite approaching the Curie temperature of the piezoelectric material. The piezoelectric sensors, here monitoring force impact in smart glass applications, are characterized by using a calibrated impact hammer system and standardized impact situations. Stand‐alone piezoelectric sensors and piezoelectric sensors integrated on poly(methyl methacrylate) are also evaluated. The piezoelectric constants obtained from the measurements of the nonintegrated piezoelectric sensors are in good agreement with the literature. The piezoelectric sensor response is measured by using either physical electrical contacts between the piezoelectric sensors and the readout electronics, or wirelessly via both noncontact capacitive coupling and Bluetooth low‐energy radio link. The developed sensor concept is finally demonstrated in smart window prototypes, in which integrated piezoelectric sensors are used to detect break‐in attempts. Additionally, each prototype includes an electrochromic film to control the light transmittance of the window, a screen printed electrochromic display for status indications and wireless communication with an external server, and a holistic approach of hybrid printed electronic systems targeting smart multifunctional glass applications.
Visualizing In‐Plane Junctions in Nitrogen‐Doped Graphene
Authors: Bouatou Mehdi , Chacon Cyril , Lorentzen Aleksander Bach , Ngo Huu Thoai , Girard Yann , Repain Vincent , Bellec Amandine , Rousset Sylvie , Brandbyge Mads , Dappe Yannick J. , Lagoute Jérôme
Published: September 2022

Controlling the spatial distribution of dopants in graphene is the gateway to the realization of graphene‐based electronic components. Here, it is shown that a submonolayer of self‐assembled physisorbed molecules can be used as a resist during a post‐synthesis nitrogen doping process to realize a nanopatterning of nitrogen dopants in graphene. The resulting formation of domains with different nitrogen concentrations allows obtaining n–n’ and p–n junctions in graphene. A scanning tunneling microscopy is used to measure the electronic properties of the junctions at the atomic scale and reveal their intrinsic width that is found to be ≈7 nm corresponding to a sharp junction regime.
Interfacial Engineering towards Enhanced Photovoltaic Performance of Sb2Se3 Solar Cell
Authors: Cai Huiling , Cao Rui , Gao Jinxiang , Qian Chen , Che Bo , Tang Rongfeng , Zhu Changfei , Chen Tao
Published: September 2022

Antimony selenide (Sb2Se3) is a kind of emerging candidate for the application in low‐cost and high‐efficiency thin film solar cells owing to its non‐toxicity, earth‐abundance, and unique quasi‐1D crystal structure. In this photovoltaic material, quasi‐vertically oriented Sb2Se3 thin films can transfer photocarriers efficiently along the [hk1]‐orientation. However, the crystal orientation control in thin films is still the main obstacle to improve the efficiency of Sb2Se3 solar cells. Herein, an interfacial engineering method is developed by antimony chloride (SbCl3) on CdS films with post‐annealing treatment to improve the quality of both interface and absorber thin film. It is found that the SbCl3 treatment resulted in 1) transformation of the CdS/Sb2Se3 interface from “cliff” to “spike” like energy band alignments; 2) improved surface morphology of CdS surface, and 3) suppressed cubic structure of CdS structure and thus generating improved [hk1]‐oriented Sb2Se3 film on the high‐purity hexagonal CdS. As a result, the Sb2Se3 solar cell treated with SbCl3 achieves a top efficiency of 6.89% in superstrate planar heterojunction Sb2Se3 solar cell. This study provides a new interfacial post‐treatment method for the preparation of high‐performance Sb2Se3 planar heterojunction solar cells.
Modeling Biochemical Gradients In Vitro to Control Cell Compartmentalization in a Microengineered 3D Model of the Intestinal Epithelium
Authors: Altay Gizem , Abad‐Lázaro Aina , Gualda Emilio J. , Folch Jordi , Insa Claudia , Tosi Sébastien , Hernando‐Momblona Xavier , Batlle Eduard , Loza‐Álvarez Pablo , Fernández‐Majada Vanesa , Martinez Elena
Published: September 2022

Gradients of signaling pathways within the intestinal stem cell (ISC) niche are instrumental for cellular compartmentalization and tissue function, yet how are they sensed by the epithelium is still not fully understood. Here a new in vitro model of the small intestine based on primary epithelial cells (i), apically accessible (ii), with native tissue mechanical properties and controlled mesh size (iii), 3D villus‐like architecture (iv), and precisely controlled biomolecular gradients of the ISC niche (v) is presented. Biochemical gradients are formed through hydrogel‐based scaffolds by free diffusion from a source to a sink chamber. To confirm the establishment of spatiotemporally controlled gradients, light‐sheet fluorescence microscopy and in‐silico modeling are employed. The ISC niche biochemical gradients coming from the stroma and applied along the villus axis lead to the in vivo‐like compartmentalization of the proliferative and differentiated cells, while changing the composition and concentration of the biochemical factors affects the cellular organization along the villus axis. This novel 3D in vitro intestinal model derived from organoids recapitulates both the villus‐like architecture and the gradients of ISC biochemical factors, thus opening the possibility to study in vitro the nature of such gradients and the resulting cellular response.
Electron‐Selective Contacts ATO/LiF/Al‐Based High‐Performance N‐Type Silicon Solar Cells
Authors: Liu Ying , Zhang Lijuan , Cheng Hao , Song Xiaomin , Zhong Sihua , Shi Linxing , Huang Zengguang
Published: September 2022

Due to its excellent passivation and low contact resistivity, Al‐doped TiO2(ATO) has become one of the most promising candidates for dopant‐free carriers‐selective contacts (CSCs). This work prepares the ATO/LiF/Al electron‐selective contacts and applies them to the n‐type silicon solar cells as full‐area rear CSCs. It is found that 6 nm‐thickness ATO thin film possesses the highest minority carrier lifetime of 253.0 µs on solar‐grade Cz n‐type wafers, revealing the ultra‐low saturated current densityJ0of 120.7 fA cm−2. Meanwhile, the 6 nm‐ATO/LiF/Al electron‐selective contact has a significantly low contact resistivity ρcof 19.7 mΩ cm2, suggesting a sound electronic transport property of the ATO/LiF/Al stack. Finally, a highest solar cell efficiency of 19.9% is obtained for an n‐type crystalline silicon device with a full‐area rear ATO/LiF/Al contact. The calculated selectivityS10of 13.0 enables the maximum efficiency of 27.3% for the ATO/LiF/Al‐based n‐type solar cell, demonstrating the great potential of applying this passivating contact in high‐efficiency silicon solar cells.
Diastereodivergent Synthesis of Syn‐ and Anti‐9‐Hydroxyhomoisoflavanone and its Application to the Total Syntheses of (±)‐Homoferrugenone and (±)‐Portulacanone F
Authors: Lee Sanha , Kwon Sangil , Hur Joonseong , Seo Seung‐Yong
Published: September 2022

The diastereodivergent synthesis of syn‐ and anti‐9‐hydroxyhomoisoflavanone from various chromones and carbaldehydes is described. The synthetic approaches involving the reductive aldol reaction or the Morita‐Baylis‐Hillman reaction followed by syn‐selective 1,4‐reduction provide both diastereomers of β‐hydroxy chroman‐4‐ones in 51–98% yield with anti (2 : 1–16 : 1 anti/syn) or 22–80% yield with syn (5 : 1–48 : 1 syn/anti) diastereoselectivity. The ambiguity surrounding the stereochemistry of two 9‐hydroxyhomoisoflavanones, homoferrugenone and portulacanone F was elucidated via the first total syntheses.

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Triethyamine‐promoted [5+3] Cycloadditions for Regio‐ and Diastereoselective Synthesis of Functionalized aza‐Bicyclo[3.3.1]alkenones
Authors: Huang Jing , Jiang Bo , Zhang Xiyuan , Gao Yanfeng , Xu Xiufang , Miao Zhiwei
Published: September 2022

We have developed a synthetic strategy for Et3N‐promoted [5+3] cycloaddition reactions between acetoxypyranones and azomethine imines to access functionalized azabicyclo[3.3.1]alkenones with three tertiary stereocenters (31 examples, 36% to 87% yield, 5.5:1 to >20:1 dr). The method was scalable, and the products could be transformed to various eight‐membered‐ring bridged heterocyclic molecules.

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An Atypical Acyl‐CoA Synthetase Enables Efficient Biosynthesis of Extender Units for Engineering a Polyketide Carbon Scaffold
Authors: Zheng Mengmeng , Zhang Jun , Zhang Wan , Yang Lu , Yan Xiaoli , Tian Wenya , Liu Zhihao , Lin Zhi , Deng Zixin , Qu Xudong
Published: September 2022

Acyl‐CoAs are key precursors of primary and secondary metabolism. Their efficient biosynthesis is often impeded by the limited substrate specificity and low in vivo activity of acyl‐CoA synthetases (ACSs) due to regulatory acylation of the catalytically important lysine residue in motif A10 (Lys‐A10). In this study, we identified an unusual ACS (UkaQ) from the UK‐2A biosynthetic pathway that naturally lacks the Lys‐A10 residue and exhibits extraordinarily broad substrate specificity. Protein engineering significantly improved its stability and catalytic activity, enabling it to synthesize a large variety of acyl‐CoAs with highly robust activity. By combining it with permissive carboxylases, we produced a large array of polyketide extender units and obtained six novel halobenzyl‐containing antimycin analogues through an engineered biosynthetic pathway. This study significantly expands the catalytic mode of ACSs and provides a potent tool for the biosynthesis of acyl‐CoA‐derived natural products.
Endohedrally Functionalized Heteroleptic Coordination Cages for Phosphate Ester Binding
Authors: Platzek André , Juber Selina , Yurtseven Cem , Hasegawa Shota , Schneider Laura , Drechsler Christoph , Ebbert Kristina E. , Rudolf Robin , Yan Qian‐Qian , Holstein Julian J. , Schäfer Lars V. , Clever Guido H.
Published: September 2022

Metallosupramolecular hosts of nanoscopic dimensions, which are able to serve as selective receptors and catalysts, are usually composed of only one type of organic ligand, restricting diversity in terms of cavity shape and functional group decoration. We report a series of heteroleptic [Pd2A2B2] coordination cages that self‐assemble from a library of shape complementary bis‐monodentate ligands in a non‐statistical fashion. Ligands A feature an inward pointing NH function, able to engage in hydrogen bonding and amenable to being functionalized with amide and alkyl substituents. Ligands B comprise tricyclic aromatic backbones of different shape and electronic situation. The obtained heteroleptic coordination cages were investigated for their ability to bind phosphate diesters as guests. All‐atom molecular dynamics (MD) simulations in explicit solvent were conducted to understand the mechanistic relationships behind the experimentally determined guest affinities.
Morphology and Light‐Dependent Spatial Distribution of Spin Defects in Carbon Nitride
Authors: Actis Arianna , Melchionna Michele , Filippini Giacomo , Fornasiero Paolo , Prato Maurizio , Salvadori Enrico , Chiesa Mario
Published: September 2022

Carbon nitride (CN) is a heterogeneous photocatalyst that combines good structural properties and a broad scope. The photocatalytic efficiency of CN is associated with the presence of defective and radical species. An accurate description of defective states—both at a local and extended level—is key to develop a thorough mechanistic understanding of the photophysics of CN. In turn, this will maximise the generation and usage of photogenerated charge carriers and minimise wasteful charge recombination. Here the influence of morphology and light‐excitation on the number and chemical nature of radical defects is assessed. By exploiting the magnetic dipole‐dipole coupling, the spatial distribution of native radicals in CN is derived with high precision. From the analysis an average distance in the range 1.99–2.34 nm is determined, which corresponds to pairs of radicals located approximately four tri‐s‐triazine units apart.
Closed‐Loop Recycling of Poly(Imine‐Carbonate) Derived from Plastic Waste and Bio‐based Resources
Authors: Saito Keita , Eisenreich Fabian , Türel Tankut , Tomović Željko
Published: September 2022

Closed‐loop recycling of polymers represents the key technology to convert plastic waste in a sustainable fashion. Efficient chemical recycling and upcycling strategies are thus highly sought‐after to establish a circular plastic economy. Here, we present the selective chemical depolymerization of polycarbonate by employing a vanillin derivative as bio‐based feedstock. The resulting di‐vanillin carbonate monomer was used in combination with various amines to construct a library of reprocessable poly(imine‐carbonate)s, which show tailor‐made thermal and mechanical properties. These novel poly(imine‐carbonate)s exhibit excellent recyclability under acidic and energy‐efficient conditions. This allows the recovery of monomers in high yields and purity for immediate reuse, even when mixed with various commodity plastics. This work provides exciting new insights in the design of bio‐based circular polymers produced by upcycling of plastic waste with minimal environmental impact.
Synergistic Interfacial Bonding in Reduced Graphene Oxide Fiber Cathodes Containing Polypyrrole@sulfur Nanospheres for Flexible Energy Storage
Authors: Huang Lei , Guan Tuxiang , Su Han , Zhong Yu , Cao Feng , Zhang Yongqi , Xia Xinhui , Wang Xiuli , Bao Ningzhong , Tu Jiangping
Published: September 2022

Flexible lithium sulfur batteries with high energy density and good mechanical flexibility are highly desirable. Here, we report a synergistic interface bonding enhancement strategy to construct flexible fiber‐shaped composite cathodes, in which polypyrrole@sulfur (PPy@S) nanospheres are homogeneously implanted into the built‐in cavity of self‐assembled reduced graphene oxide fibers (rGOFs) by a facile microfluidic assembly method. In this architecture, sulfur nanospheres and lithium polysulfides are synergistically hosted by carbon and polymer interface, which work together to provide enhanced interface chemical bonding to endow the cathode with good adsorption ability, fast reaction kinetics, and excellent mechanical flexibility. Consequently, the PPy@S/rGOFs cathode shows enhanced electrochemical performance and high‐rate capability. COMSOL Multiphysics simulations and density functional theory (DFT) calculations are conducted to elucidate the enhanced electrochemical performance. In addition, a flexible Li−S pouch cell is assembled and delivers a high areal capacity of 5.8 mAh cm−2 at 0.2 A g−1. Our work offers a new strategy for preparation of advanced cathodes for flexible batteries.
Determination of mean activity coefficients and prediction of phase equilibria of the NaCl‐SrCl2‐H2O solution at 318.15 K
Authors: Sang Shi‐Hua , Fu Yang‐Xiao , Ge Qi , Liu Jia , Cui Rui‐Zhi
Published: September 2022

In this work, the cell potential method is used to measure activity coefficients of NaCl‐SrCl2‐H2O mixed solution at 318.15 K. The potential values of NaCl in NaCl‐H2O single salt solution were measured, and the standard cell potential E0 and electrode response slope k were fitted with linear regression. Subsequently, the results show that the ion‐selective electrode has a good Nernst response. The mean activity coefficients NaCl in NaCl‐SrCl2‐H2O solution are also determined with Nernst equation, and the total ionic strength in the mixed solution range is from 0.1000 ~ 0.8000 mol·kg−1, the ionic strength fraction of SrCl2 with yb = (0.0, 0.2, 0.4, 0.6, 0.8). Using the mean activity coefficients data and Pitzer model, the Pitzer ion interaction parameters
and
of Pitzer equations at 318.15 K are fitted. Furthermore, the mean activity coefficients of SrCl2, permeability coefficient Φ, water activity aw, and excess Gibbs free energy GE were also calculated by Pitzer's equations. The phase equilibria of the NaCl‐SrCl2‐H2O solution at 318.15 K are predicted, and corresponding phase diagram of the ternary solution is plotted according to the calculated solubilities in this work, and comparison of phase equilibria at different temperatures is also presented. The results show that the ion interaction parameters of Pitzer equations obtained in this work can be used for calculation of thermodynamic parameters and prediction of phase equilibria of salt‐water solutions containing strontium.
A strategy to improve the compatibility of carboxyl methyl cellulose with silica fume‐based geopolymer inorganic siliceous coatings for flame‐retarding plywood
Authors: Wang YaChao , Kou Xiaofei , Zhao JiangPing , Deng Jun
Published: September 2022

To seek an effective strategy for improving the compatibility of carboxyl methyl cellulose (CMC) with silica fume‐based geopolymer composite flame‐retarding coatings, a novel silica aerogel (SA) doped inorganic siliceous hybrid coating is fabricated by sol–gel. Results show that an appropriate dosage (0.5 wt%) of SA ameliorates their compatibility thus imparting an enhanced flame resistance, evidenced by the lowest value of fire growth index (0.22 kW·m−2·s−1) decreased by 55% and the average effective heat of combustion (4.16 kW·kg−1) decreased by 31%, the raised flame retardancy index of 5.54 from 1 compared with the control. Because the SA improves the compatibility between the CMC and siliceous colloidal sol, due to its high reactivity, electrostatic repulsion involved in SiO(OH)3−, and high porosity, leading to an enhanced crosslinking during film‐forming of the hybrid coatings. Meanwhile, the reduction between CMC and silica occurs with a swelling fire shield, evidenced by the generated silicon involved in the as‐formed amorphous siliceous residues. Therefore, it proposed a new strategy for optimizing the compatibility of organic–inorganic hybrid fireproof coatings, revealing an efficient design of CMC/inorganic siliceous flame retardants, high‐value recycling technology of solid waste, low‐carbon, and sustainable materials.
Solid‐state Nanopores: Chemical Modifications, Interactions, and Functionalities
Authors: Yang Lei , Hu Jun , Li Min‐Chao , Xu Ming , Gu Zhi‐Yuan
Published: September 2022

Nanopore technology is a burgeoning detection technology for single‐molecular sensing and ion rectification. Solid‐state nanopores have attracted more and more attention because of their higher stability and tunability than biological nanopores. However, solid‐state nanopores still suffer the drawbacks of low signal‐to‐noise ratio and low resolution, which hinder their practical applications. Thus, developing operatical and useful methods to overcome the shortages of solid‐state nanopores is urgently needed. Here, we summarize the recent research on nanopore modification to achieve this goal. Modifying solid‐state nanopores with different coating molecules can improve the selectivity, sensitivity, and stability of nanopores. The modified molecules can introduce different functions into the nanopores, greatly expanding the applications of this novel detection technology. We hope that this review of nanopore modification will provide new ideas for this field.
Visible Light Driven Metal‐Free Photoredox Catalyzed α‐benzylation and α‐oxygenation of N‐substituted Tetrahydroisoquinolines: Applications to Synthesis of Natural Products
Authors: Elavarasan Selvaraj , Preety Jeyaraj , Abinaya Ramanjulu , Saravanan Thangavelu , Balasubramanian Kalpattu Kuppusamy , Venkatramaiah Nutalapati , Baskar Baburaj
Published: September 2022

Herein, visible light mediated organophoto redox catalysed simple and convenient method for the α‐benzylation and α‐oxygenation of tertiary amines is demonstrated. Synthesis of novel thiophenol based donor acceptor organophotoredox catalysts 4 a–4 d were investigated along with commercial catalyst 4‐CzIPN (4 e). A diverse biologically active α‐benzylated tetrahydroisoquinolines and natural products such as (±)‐Norlaudanosine, (±)‐laudanosine and (±)‐xylopinine have been synthesized under the optimized conditions in yields ranging from from 62–91%. Exploitation of synthesized α‐benzylated compound using present phtoredox catalyzed conditions gave rise to dehydyrogenative benzylic oxidation product under oxygen atmosphere which is known to display biologically and structurally important properties. Also, various N‐protected tertiary amines were found to be suitable for the α‐oxygenation reactions using catalyst 4 e and resulted in good yields (61–85%).
Progress, challenges, and future steps in data assimilation for convection‐permitting numerical weather prediction: Report on the virtual meeting held on 10 and 12 November 2021
Authors: Hu Guannan , Dance Sarah L. , Bannister Ross N. , Chipilski Hristo G. , Guillet Oliver , Macpherson Bruce , Weissmann Martin , Yussouf Nusrat
Published: September 2022

In November 2021, the Royal Meteorological Society Data Assimilation (DA) Special Interest Group and the University of Reading hosted a virtual meeting on the topic of DA for convection‐permitting numerical weather prediction. The goal of the meeting was to discuss recent developments and review the challenges including methodological developments and progress in making the best use of observations. The meeting took place over two half days on the 10 and 12 November, and consisted of six talks and a panel discussion. The scientific presentations highlighted some recent work from Europe and the USA on convection‐permitting DA including novel developments in the assimilation of observations such as cloud‐affected satellite radiances in visible channels, ground‐based profiling networks, aircraft data, and radar reflectivity data, as well as methodological advancements in background and observation error covariance modelling and progress in operational systems. The panel discussion focused on key future challenges including the handling of multiscales (synoptic‐, meso‐, and convective‐scales), ensemble design, the specification of background and observation error covariances, and better use of observations. These will be critical issues to address in order to improve short‐range forecasts and nowcasts of hazardous weather.
The Potential Application of Branch‐PCR Assembled PTEN Gene Nanovector in Lung Cancer Gene Therapy
Authors: Lu Liqing , Fang Tian , Pang Tuo , Chen Ziyi , Cheng Longhuai , Ma Dejun , Xi Zhen
Published: September 2022

Gene therapy offers an alternative and promising avenue to lung cancer treatment. Here, we used dibenzocyclooctyne (DBCO)‐branched primers to construct a PTEN gene nanovector (NP‐PTEN) through branch‐PCR. NP‐PTEN showed the nanoscale structure with biocompatible size (84.7±11.2 nm) and retained the improved serum stability compared to linear DNA. When transfected into NCI‐H1299 cancer cells, NP‐PTEN could overexpress PTEN protein to restore PTEN functions through the deactivation of PI3K‐AKT‐mTOR signaling pathway to inhibit cell proliferation and induce cell apoptosis. The apoptosis rate of NCI‐H1299 cancer cells could reach up to 54.5 %±4.6 % when the transfection concentration of NP‐PTEN was 4.0 μg/mL. In mice bearing NCI‐H1299 tumor xenograft intratumorally administrated with NP‐PTEN, the average tumor volume and tumor weight was separately reduced by 61.7 % and 63.9 %, respectively, compared with the PBS group on the 18th day of administration. The anticancer efficacy of NP‐PTEN in NCI‐H1299 tumor xenograft suggests the promising therapeutic potential of branch‐PCR assembled PTEN gene nanovectors in lung cancer gene therapy and also provided more opportunities to introduce two or more tumor suppressor genes as an all‐in‐one gene nanovector for multiple gene‐based cancer gene therapy.
Harnessing the Therapeutic Potential and Biological Activity of Antiviral Peptides
Authors: Guarracino Danielle A. , Iannaccone Jacqueline , Cabrera Alexander , Kancharla Sneha
Published: September 2022

Peptides are ideal candidates for the development of antiviral therapeutics due to their specificity, chemical diversity and potential for highly potent, safe, molecular interventions. By restricting conformational freedom and flexibility, cyclic peptides frequently increase peptide stability. Viral targets are often very challenging as their evasive strategies for infectivity can preclude standard therapies. In recent years, several peptides from natural sources mitigated an array of viral infections. In parallel, short peptides derived from key viral proteins, modified with chemical groups such as lipids and cell‐penetrating sequences, led to highly effective antiviral inhibitor designs. These strategies have been further developed during the recent COVID‐19 pandemic caused by the novel coronavirus SARS‐CoV‐2. Several anti‐SARS‐CoV‐2 peptides are gaining ground in pre‐clinical development. Overall, peptides are strong contenders for lead compounds against many life‐threatening viruses and may prove to be the key to future efforts revealing viral mechanisms of action and alleviating their effects.
Radiation reduction in a modern catheterization laboratory: A single‐center experience
Authors: Shekhar Shashank , Ajay Abhishek , Agrawal Ankit , Kumar Anirudh , Kaur Manpreet , Isogai Toshiaki , Saad Anas , Abushouk Abdelrahman I. , Abdelfattah Omar , Lak Hassan , Farwati Medhat , Ahuja Keerat , Verma Beni R. , Wunderle Kevin , Ellis Stephen , Khatri Jaikirshan , Ziada Khaled , Krishnaswamy Amar , Kapadia Samir
Published: September 2022

Background

Measures were undertaken at the Cleveland Clinic to reduce radiation exposure to patients and personnel working in the catheterization laboratories. We report our experience with these improved systems over a 7‐year period in patients undergoing diagnostic catheterization (DC) and percutaneous coronary interventions (PCIs).

Methods

Patients were categorized into preinitiative (2009–2012) and postinitiative (2013–2019) groups in the DC and PCI cohorts. Propensity score matching was done between the pre‐ and postinitiative groups for both cohorts based on age, sex, body surface area, total fluoroscopy time, and total acquisition time. The effectiveness of radiation reduction measures was assessed by comparing the total air kerma (Ka,r), and fluoroscopy‐ and acquisition‐mode air kerma in patients in the two groups.

Results

In the DC cohort, there was a significant reduction in Ka,r in the postinitiative group in comparison to the preinitiative group (median, 396 vs. 857 mGy; p < 0.001). In the PCI cohort, Ka,r in the postinitiative group was 1265 mGy, which was significantly lower than the corresponding values in the preinitiative group (1994 mGy; p < 0.001). We also observed a significant reduction in fluoroscopy‐ and acquisition‐based air kerma rates, and air kerma area product in the postinitiative group in comparison to the preinitiative group in both matched and unmatched DC and PCI cohorts after the institution of radiation reduction measures.

Conclusion

There was a significant and sustained reduction in radiation exposure to patients in the catheterization laboratory with the implementation of advanced protocols. Similar algorithms can be applied in other laboratories to achieve a similar reduction in radiation exposure.
Kolorimetrische Bestimmung von Nitrat
Authors: Czubatinski Lars , Hemm Harald , Hornung Gabriele
Published: September 2022

Mit der vorliegenden Arbeit wurde ein empfindliches Verfahren zur Bestimmung von Nitrat in Stillgewässern im Feld etabliert. Der Nitrat‐Nachweis erfolgt analog der vom Grieß‐Reagenz bekannten Farbreaktion. Die Methode wurde aber so modifiziert, dass sie vor Ort am Gewässer durchgeführt werden kann. Zu diesem Zweck wurde auch eine Messeinrichtung entwickelt, die eine einfache kolorimetrische Auswertung im Freiland zulässt. Dieses „Boxometer“ setzt sich aus zwei Smartphones und wenigen Alltagsgegenständen zusammen und kann von Laien kostengünstig und einfach nachgebaut werden. Die kolorimetrische Analyse erfolgt dann mit Hilfe des RGB‐Systems in einem Auflicht‐Setting, das innerhalb enger Grenzen eine sensible Untersuchung des Absorptionsverhaltens der Probelösungen erlaubt. Dieses Verfahren kann weiterhin vielseitig in der Lehre eingesetzt werden. Es kann aber auch bei Untersuchungen zur Anwendung kommen, bei denen kolorimetrische Messungen durchgeführt werden sollen, aber kein Spektralphotometer zur Verfügung steht.
Highly Efficient and Biologically Compatible Photoremovable Protecting Group for Releasing Tertiary Amines through Two‐Photon Excitation
Authors: Asad Naeem , Deodato Davide , Gore Sangram , Dore Timothy M.
Published: September 2022

Photoremovable protecting groups (PPGs) releasable by two‐photon excitation (2PE) provide spatio‐temporal control over the photoactivation of biological effectors to study biological systems. We synthesized four derivatives of the (8‐cyano‐7‐hydroxyquinolin‐2‐yl)methyl (CyHQ) chromophore by functionalization of position C4 to generate four different derivatives (MeO‐CyHQ, Mor‐CyHQ, pTol‐CyHQ, and TMP‐CyHQ) for studying the release of tertiary amines via 2PE. Sulpiride, an anti‐dopaminergic drug, was selected as a model substrate. All probes had excellent properties for use in biological settings, including high quantum yield (Φu), hydrolytic stability, and good aqueous solubility in simulated physiological buffer. The TMP‐CyHQ probe enhanced the two‐photon uncaging action cross‐section (δu) 8‐fold (2.64 GM) compared to the parent CyHQ‐sulpiride. The optimized PPG was used to mediate the photoactivation of various biological effectors containing the tertiary amine functionality (tamoxifen, 4‐hydroxytamoxifen, yohimbine) using 2PE. All constructs showed excellent efficiency with δu ranging from 1.21 to 2.42 GM and moderate to excellent yields of tertiary amines released.
High Open‐Circuit Voltage Cs2AgBiBr6 Carbon‐Based Perovskite Solar Cells via Green Processing of Ultrasonic Spray‐Coated Carbon Electrodes from Waste Tire Sources
Authors: Schmitz Fabian , Lago Nicolò , Fagiolari Lucia , Burkhart Julian , Cester Andrea , Polo Andrea , Prato Mirko , Meneghesso Gaudenzio , Gross Silvia , Bella Federico , Lamberti Francesco , Gatti Teresa
Published: September 2022

Costs and toxicity concerns are at the center of a heated debate regarding the implementation of perovskite solar cells (PSCs) into commercial products. The first bottleneck could be overcome by eliminating the top metal electrode (generally gold) and the underlying hole transporting material and substituting both with one single thick layer of conductive carbon, as in the so‐called carbon‐based PSCs (C‐PSCs). The second issue, related to the presence of lead, can be tackled by resorting to other perovskite structures based on less toxic metallic components. An interesting case is that of the double perovskite Cs2AgBiBr6, which at present still lacks the outstanding optoelectronic performances of the lead‐based counterparts but is very stable to environmental factors. In this work, the processing of carbon electrodes onto Cs2AgBiBr6‐based C‐PSCs was reported, starting from an additive‐free isopropanol ink of a carbon material obtained from the hydrothermal recycling of waste tires and employing a high‐throughput ultrasonic spray coating method in normal environmental conditions. Through this highly sustainable approach that ensures a valuable step from an end‐of‐life to an end‐of‐waste status for used tires, devices were obtained delivering a record open circuit voltage of 1.293 V, which might in the future represent ultra‐cheap solutions to power the indoor Internet of Things ecosystem.