bluuebunny/crossref_metadata_2025 huggingface dataset:
Sound absorption of stretched ceilings with an impervious synthetic membrane
Authors: Bosmans Ivan , Lauriks Walter , Lombaert Geert , Mermans Joris , Vermeir Gerrit
Published: July 2002

The sound absorption of stretched ceilings consisting of an impervious PVC membrane is investigated. A theoretical model is used to predict the random incidence sound absorption, and results are compared with the results of an experimental setup in a reverberation chamber. The sound absorption coefficient is estimated using a general model for the acoustic transmission and absorption of a multi-layered structure. Measurements have been performed for several cavity depths, and for two different sound absorbing materials in the cavity. Both theory and experiment showed that the combination of the impervious foil and the cavity behaves as a resonant system. The sound absorption varies strongly with frequency and is highly dependent on the characteristics and the position of the sound absorbing material in the cavity.
Experimental investigations of nonlinear acoustic phenomena in polycrystalline zinc
Authors: Nazarov Veniamin E. , Kolpakov Andrei B.
Published: July 2002

The results of experimental and theoretical investigations of nonlinear acoustic phenomena (nonlinear losses, shift of resonance frequency, generation of the third harmonic, and nonlinear sound-by-sound damping) in polycrystalline zinc nonannealed and annealed resonating rods are presented. The measurements were carried out in the 10−7–10−5 strain range at a frequency of about 3 kHz; the frequency of the weak ultrasonic pulse was about 270 kHz. The experimentally observed phenomena are described in frames of phenomenological equations of state containing elastic hysteresis and dissipative nonlinearity. The nonlinear acoustic parameters of these equations are determined by comparison between theoretical dependencies and experimental results. The influence of structural changes in zinc due to annealing on the nonlinear acoustic phenomena is shown.
Computed narrow-band time-reversing array retrofocusing in a dynamic shallow ocean
Authors: Dungan Michael R. , Dowling David R.
Published: July 2002

A time-reversing array (TRA) can retrofocus acoustic energy, in both time and space, to the original sound-source location without any environmental information. This unique capability may be degraded in time-dependent or noisy acoustic environments, or when propagation losses are prevalent. In this paper, monochromatic propagation simulations (based on the parabolic equation code, RAM) are used to predict TRA retrofocusing performance in shallow-water sound channels having characteristics similar to those measured during the recent SWARM (shallow-water acoustics in a random medium) experiment. Results for the influence of source–array range, source depth, acoustic frequency, bottom absorption, internal wave strength, and round-trip time delay are presented. For a fixed channel geometry, higher frequencies, deeper sources, and lower bottom absorption improve TRA performance and allow retrofocusing at longer ranges. In a dynamic shallow-water channel containing a random superposition of linear internal waves, the size of the retrofocus is slightly decreased and sidelobes are suppressed compared to the static channel results. These improvements last for approximately 1 to 2 min for source-array ranges near 10 km at a frequency of 500 Hz. For longer time delays, the internal waves cause significant TRA retrofocus amplitude decay, and the decay rate increases with increasing internal wave activity and acoustic frequency.
Peel Adhesion: Micro-Fracture Mechanics of Interfacial Unbonding of Polymers
Authors: Kaelble D. H.
Published: July 2002

A simple and precise means of measuring internal bond stresses in peel is now available. By the use of a newly designed “bond stress analyzer” the magnitude and positional distribution of internal normal stresses may be measured during peel. The design theory, construction, and operation of the instrument are reviewed in detail. The influence of the angle of peeling upon the cleavage stress distribution is investigated and analyzed. The results, interpreted in terms of present theory of peel adhesion, suggest that the peel test is a valid measure of interfacial adhesion properties only at a peel angle of w=π rad=180 deg. The detailed form of the cleavage stress function in the region of boundary fracture indicates that cavitation and orientation processes contribute importantly to high peel strengths in elastomeric adhesive interlayers.
The effects of shielding on viscous drag forces operating on chain-like macromolecules
Authors: Feng S. S. , MacDonald R. C. , Abraham B. M.
Published: July 2002

A theoretical analysis is developed to compute the extensional force exerted on a fully stretched macromolecule in an elongational flow of a given extensional strain rate. The long chain molecules are described by a bead-on-a-string model. The dynamic problem in the external flow field is solved by the boundary collocation truncated series method. The total stretching force is then computed from the viscous stresses on the surfaces of each bead. This approach permits calculation of the magnitude of interbead shielding effects. Current practice for estimating stretching and fracture forces on macromolecules in elongational flow experiments involves application of Stokes law to each bead as though the flow around it were independent of that around the others. In the present analysis, an analytical expression for the shielding factor is developed. An approximate formula relating shielding effects to molecular weight is extracted from the results of numerical computation. Using this formula it is proved that the free-draining Rouse model and the non-free-draining Zimm model represent opposite extremes with respect to shielding effects. Also, a more accurate power index in the relationship between relaxation time and molecular weight is given. A calculation is also carried out for spectrin, the protein molecule responsible for the elasticity of the red blood cell membrane, as an application example. On the basis of a chain of 40 beads separated by 50 Å and having a radius 12.5 Å, a shielding factor of 37% was calculated. Thus, even for this relatively short polymer, the neglect of shielding would overestimate the drag on its surface by a factor of 2.7.
Stability of a periodic unidirectional flow of viscoelastic fluids
Authors: Brutyan M. A. , Krapivsky P. L.
Published: July 2002

We investigate the stability of a periodic unidirectional two-dimensional flow of viscoelastic fluid. An exact value of the critical Reynolds number Rc is found for two models of a viscoelastic material: the upper convected Maxwell fluid and the Oldroyd B or Boger fluid.
Analysis of isothermal spinning of liquid-crystalline polymers
Authors: Ramalingam Suresh , Armstrong R. C.
Published: July 2002

In this paper we use the constitutive equation of Bhave et al. (1993) for rod-like, liquid-crystalline polymer solutions to analyze the isothermal, steady-state spinning of these liquids in order to understand the evolution of microstructure, predict the velocity and normal stress distributions in the filament, and examine the effect of different upstream microstructural conditions. Our analysis shows that in contrast to fiber spinning models of isotropic liquids, the velocity, structure, and stress profiles are sensitive to the choice of initial conditions. In addition we have investigated the impact of the closure approximation used in the constitutive equation of Bhave et al. on the fiber spinning problem by solving the equation for the distribution function directly; only slight changes are seen in the velocity and stress profiles. An apparent elongational viscosity defined as the ratio of normal stress difference to strain rate at the takeup compares very well with the true elongational viscosity η̄ for the model, thereby suggesting that fiber spinning flows can be used to determine η̄ for liquid-crystalline polymer solutions. Model predictions of the velocity and stress agree well with data obtained by Prilutski (1984) for HPC/acetic acid solutions. Finally, we present a linear stability analysis of the spinning problem to show the impact of viscoelasticity, inertia, gravity, and surface tension on the onset of draw resonance instabilities. The neutral stability curves obtained for dominant viscoelastic forces reflect trends in the apparent elongational viscosity. Model predictions are in qualitative agreement with the draw resonance data reported by Prilutski.
A new method for determination of normal-stress differences in highly viscoelastic substances using a modified Weissenberg rheometer
Authors: Eggers H. , Schümmer P.
Published: July 2002

This paper presents a new experimental approach for determining both normal-stress differences using a modification of the Weissenberg rheometer. The method eliminates both wall slippage and rim fracture that so far have been major obstacles in attaining steady-state flow conditions with highly consistent fluids in rotational instruments. This is achieved by extending the upper plate with a separately moving exterior ring that is closed on the outside. For determination of both normal-stress differences with this modification, the wall pressure at the radius of separation is to be measured in addition to the integral force on the inner plate, yielding a set of linear differential equations in N2 with linear terms in N1. Combining two geometrical configurations from the cone-and-plate, cone-plate-distance, and parallel-plates systems, a differential equation in N2 only is obtained whose solution can be determined from a quadrature of the measured mechanical quantities. N1 results from the equations after reintroduction of the solution for the second normal-stress difference.
A high pressure sliding plate rheometer for polymer melts
Authors: Koran François , Dealy John M.
Published: July 2002

A high-pressure sliding plate rheometer has been developed to investigate the effect of pressure on the rheological behavior of molten polymers and elastomers. The new rheometer operates at pressures up to 70 MPa and temperatures up to 225 °C. The sample is subjected to simple shear, and the resulting shear stress is measured locally using a shear stress transducer. This design eliminates the inhomogeneities in pressure and shear rate that occur in high pressure capillary and slit rheometers. Preliminary evaluation of the new instrument was carried out using a linear low density polyethylene. Viscosity curves were generated at pressures ranging from atmospheric pressure to 70 MPa, and the pressure coefficient of viscosity was determined. Experiments were also carried out in step strain and large amplitude oscillatory shear, demonstrating the new rheometer’s use to study the nonlinear viscoelastic behavior of molten polymers. Finally, this instrument was used to study strain-induced crystallization.
Backbone Engineering Enables Highly Efficient Polymer Hole‐Transporting Materials for Inverted Perovskite Solar Cells
Authors: Wu Xin , Gao Danpeng , Sun Xianglang , Zhang Shoufeng , Wang Qi , Li Bo , Li Zhen , Qin Minchao , Jiang Xiaofen , Zhang Chunlei , Li Zhuo , Lu Xinhui , Li Nan , Xiao Shuang , Zhong Xiaoyan , Yang Shangfeng , Li Zhong'an , Zhu Zonglong
Published: December 2022

The interface and crystallinity of perovskite films play a decisive role in determining the device performance, which is significantly influenced by the bottom hole‐transporting material (HTM) of inverted perovskite solar cells (PVSCs). Herein, a simple design strategy of polymer HTMs is reported, which can modulate the wettability and promote the anchoring by introducing pyridine units into the polyarylamine backbone, so as to realize efficient and stable inverted PVSCs. The HTM properties can be effectively modified by varying the linkage sites of pyridine units, and 3,5‐linked PTAA‐P1 particularly demonstrates a more regulated molecular configuration for interacting with perovskites, leading to highly crystalline perovskite films with uniform back contact and reduced defect density. Dopant‐free PTAA‐P1‐based inverted PVSCs have realized remarkable efficiencies of 24.89% (certified value: 24.50%) for small‐area (0.08 cm2) as well as 23.12% for large‐area (1 cm2) devices. Moreover, the unencapsulated device maintains over 93% of its initial efficiency after 800 h of maximum power point tracking under simulated AM 1.5G illumination.
High‐Q Nanophotonics over the Full Visible Spectrum Enabled by Hexagonal Boron Nitride Metasurfaces
Authors: Kühner Lucca , Sortino Luca , Tilmann Benjamin , Weber Thomas , Watanabe Kenji , Taniguchi Takashi , Maier Stefan A. , Tittl Andreas
Published: December 2022

All‐dielectric optical metasurfaces with high quality (Q) factors have been hampered by the lack of simultaneously lossless and high‐refractive‐index materials over the full visible spectrum. In fact, the use of low‐refractive‐index materials is unavoidable for extending the spectral coverage due to the inverse correlation between the bandgap energy (and therefore the optical losses) and the refractive index (n). However, for Mie resonant photonics, smaller refractive indices are associated with reduced Q factors and low mode volume confinement. Here, symmetry‐broken quasi bound states in the continuum (qBICs) are leveraged to efficiently suppress radiation losses from the low‐index (n ≈ 2) van der Waals material hexagonal boron nitride (hBN), realizing metasurfaces with high‐Q resonances over the complete visible spectrum. The rational use of low‐ and high‐refractive‐index materials as resonator components is analyzed and the insights are harnessed to experimentally demonstrate sharp qBIC resonances with Q factors above 300, spanning wavelengths between 400 and 1000 nm from a single hBN flake. Moreover, the enhanced electric near fields are utilized to demonstrate second‐harmonic generation with enhancement factors above 102. These results provide a theoretical and experimental framework for the implementation of low‐refractive‐index materials as photonic media for metaoptics.
Bioinspired Self‐Growing Hydrogels by Harnessing Interfacial Polymerization
Authors: Jian Nannan , Guo Rui , Zuo Lei , Sun Yibo , Xue Yu , Liu Ji , Zhang Kai
Published: December 2022

The production of natural materials is achieved through a bottom‐up approach, in which materials spontaneously grow and adapt to the external environment. Synthetic materials are specifically designed and fabricated as engineered materials; however, they are far away from these natural self‐growing attributes. Thus, design and fabrication of synthetic material systems to replicate the self‐growing characteristics of those natural prototypes (i.e., hairs and nails) remains challenging. Inspired by the self‐growing behaviors of keratin proteins, here the fabrication of synthetic hydrogels (i.e., polyacrylamide (PAAm)) from the free radical polymerization at the interface between AAm precursor solution and liquid metals (i.e., eutectic gallium–indium (EGaIn)) is reported. The newly formed hydrogel materials at the EGaIn/AAm precursor interface gradually push the whole hydrogel upward, enabling the self‐growing of these synthetic hydrogel materials. This work not only endows the fabrication of synthetic materials with unprecedented self‐growing characters, but also broadens the potential applications of self‐growing materials in actuation and soft robotics.
Aqueous Two‐Phase Enabled Low Viscosity 3D (LoV3D) Bioprinting of Living Matter
Authors: Becker Malin , Gurian Melvin , Schot Maik , Leijten Jeroen
Published: December 2022

Embedded 3D bioprinting has great value for the freeform fabrication of living matter. However, embedded 3D bioprinting is currently limited to highly viscous liquid baths or liquid‐like solid baths. In contrast, prior to crosslinking, most hydrogels are formulated as low‐viscosity solutions and are therefore not directly compatible with bioprinting due to low shape fidelity and poor print stability. The authors here present a method to enable low‐viscosity ink 3D (LoV3D) bioprinting, based on aqueous two‐phase stabilization of the ink‐bath interface. LoV3D allows for the printing of living constructs at high extrusion speeds (up to 1.8 m s−1) with high viability due to its exceedingly low‐viscosity. Moreover, LoV3D liquid/liquid interfaces offer unique advantages for fusing printed structures, creating intricate vasculature, and modifying surfaces at higher efficiencies than traditional systems. Furthermore, the low interfacial tension of LoV3D bioprinting offers unprecedented nozzle‐independent control over filament diameter via large‐dimension strand‐thinning, which allows for the printing of an exceptionally wide range of diameters down to the width of a single cell. Overall, LoV3D bioprinting is a unique all‐aqueous approach with broad material compatibility without the need for rheological ink adaption, which opens new avenues of application in cell patterning, drug screening, engineered meat, and organ fabrication.
Inner‐coated highly selective thin film nanocomposite hollow fiber membranes for the mixture gas separation
Authors: Ingole Pravin G.
Published: December 2022

Polyamide‐based thin film nanocomposite (TFN) membranes were prepared by incorporating nanoparticles in an aqueous phase containing m‐phenylenediamine (MPD) and an organic phase containing trimesoyl chloride (TMC) by interfacial polymerization (IP) method. The 3‐aminopropyltrimethoxy silane grafted mesoporous synthetic hectorite (APTMSH) was synthesized and added in an aqueous monomer solution while the IP. In this work, the TFN layer interfacial compatibility has been enhanced by building the covalent bond between APTMSH and other two monomers by IP method. The coating of the TFN selective layer was done on the inner surface of polysulfone hollow fiber membranes. The interesting results were obtained for the binary mixture gas separation containing water vapor/N2 and CO2/CH4. Improved gas permeance and selectivity have been obtained using APTMSH‐incorporated TFN membranes. The developed TFN membranes have been characterized using several physicochemical methods. The results show that with the addition of APTMSH in MPD solution up to 0.5 w/w% the best water vapor permeance 2485 GPU and CO2 permeance 22.3 GPU were obtained along with water vapor/N2 selectivity 725.5 and CO2/CH4 selectivity 26.68 respectively through APTMSH@TFN‐3 membrane.
Effects of icariin and curcumol on autophagy, ferroptosis, and lipid metabolism based on miR‐7/m‐TOR/SREBP1 pathway on prostate cancer
Authors: Xu Wenjing , Ding Jin , Li Bonan , Sun Tiansong , You Xujun , He Qinghu , Sheng Wen
Published: December 2022

This study aimed to investigate the effects and underlying molecular mechanisms of icariin (ICA) and curcumol on autophagy, ferroptosis, and lipid metabolism in prostate cancer (PCa), in vitro and in vivo. Normal prostate epithelial cells RWPE‐1 and PCa cell lines DU145 and PC‐3 were treated with ICA and curcumol. Ferrostatin‐1 (Fer‐1) or 3‐MA was added to treat DU145 and PC‐3 cells. In addition, we knocked down miR‐7. The mechanism of ICA and curcumol in PCa cells after the knockdown of miR‐7 was verified by in vitro nude mice tumorigenesis experiments. ICA and curcumol had no significant effect on the viability of RWPE‐1 cells, but there was a significant difference between DU145 and PC‐3 cells. After treatment with ICA and curcumol, the proliferation of PCa cells was inhibited, apoptosis, reactive oxygen species (ROS) levels, and miR‐7 expression were increased. The combined treatment of ICA and curcumol had a more significant effect. ICA and curcumol treatment induced autophagy and ferroptosis in PCa cells, and si‐miR‐7 reversed the effects of ICA and curcumol on autophagy and ferroptosis. MiR‐7 targeted mTOR and regulated the expression of the mTOR/SREBP1 pathway in PCa cells. ICA and curcumol may affect the lipid metabolism of PCa cells by affecting SREBP1. In addition, the effects and mechanisms of ICA and curcumol on autophagy, ferroptosis, and lipid metabolism in PCa cells were verified in vivo. ICA and curcumol synergistically regulated the miR‐7/mTOR/SREBP1 pathway to induce autophagy and ferroptosis in PCa cells and affected lipid metabolism.
Characterization and implications of host‐cell protein aggregates in biopharmaceutical processing
Authors: Oh Young Hoon , Becker Matthew L. , Mendola Kerri M. , Choe Leila H. , Min Lie , Lee Kelvin H. , Yigzaw Yinges , Seay Alexander , Bill Jerome , Li Xuanwen , Roush David J. , Cramer Steven M. , Menegatti Stefano , Lenhoff Abraham M.
Published: December 2022

In the production of biopharmaceuticals such as monoclonal antibodies (mAbs) and vaccines, the residual amounts of host‐cell proteins (HCPs) are among the critical quality attributes. In addition to overall HCP levels, individual HCPs may elude purification, potentially causing issues in product stability or patient safety. Such HCP persistence has been attributed mainly to biophysical interactions between individual HCPs and the product, resin media, or residual chromatin particles. Based on measurements on process streams from seven mAb processes, we have found that HCPs in aggregates, not necessarily chromatin‐derived, may play a significant role in the persistence of many HCPs. Such aggregates may also hinder accurate detection of HCPs using existing proteomics methods. The findings also highlight that certain HCPs may be difficult to remove because of their functional complementarity to the product; specifically, chaperones and other proteins involved in the unfolded protein response (UPR) are disproportionately present in the aggregates. The methods and findings described here expand our understanding of the origins and potential behavior of HCPs in cell‐based biopharmaceutical processes and may be instrumental in improving existing techniques for HCP detection and clearance.
Rapid prototyping enzyme homologs to improve titer of nicotinamide mononucleotide using a strategy combining cell‐free protein synthesis with split GFP
Authors: Yuan Qingyan , Wu Minhui , Liao Yibo , Liang Shuli , Lu Yuan , Lin Ying
Published: December 2022

Engineering biological systems to test new pathway variants containing different enzyme homologs is laborious and time‐consuming. To tackle this challenge, a strategy was developed for rapidly prototyping enzyme homologs by combining cell‐free protein synthesis (CFPS) with split green fluorescent protein (GFP). This strategy featured two main advantages: (1) dozens of enzyme homologs were parallelly produced by CFPS within hours, and (2) the expression level and activity of each homolog was determined simultaneously by using the split GFP assay. As a model, this strategy was applied to optimize a 3‐step pathway for nicotinamide mononucleotide (NMN) synthesis. Ten enzyme homologs from different organisms were selected for each step. Here, the most productive homolog of each step was identified within 24 h rather than weeks or months. Finally, the titer of NMN was increased to 1213 mg/L by improving physiochemical conditions, tuning enzyme ratios and cofactor concentrations, and decreasing the feedback inhibition, which was a more than 12‐fold improvement over the initial setup. This strategy would provide a promising way to accelerate design‐build‐test cycles for metabolic engineering to improve the production of desired products.
Targeting immune checkpoints: how to use natural killer cells for fighting against solid tumors
Authors: Ghaedrahmati Farhoodeh , Esmaeil Nafiseh , Abbaspour Maryam
Published: December 2022

Natural killer (NK) cells are unique innate immune cells that mediate anti‐viral and anti‐tumor responses. Thus, they might hold great potential for cancer immunotherapy. NK cell adoptive immunotherapy in humans has shown modest efficacy. In particular, it has failed to demonstrate therapeutic efficiency in the treatment of solid tumors, possibly due in part to the immunosuppressive tumor microenvironment (TME), which reduces NK cell immunotherapy's efficiencies. It is known that immune checkpoints play a prominent role in creating an immunosuppressive TME, leading to NK cell exhaustion and tumor immune escape. Therefore, NK cells must be reversed from their dysfunctional status and increased in their effector roles in order to improve the efficiency of cancer immunotherapy. Blockade of immune checkpoints can not only rescue NK cells from exhaustion but also augment their robust anti‐tumor activity. In this review, we discussed immune checkpoint blockade strategies with a focus on chimeric antigen receptor (CAR)‐NK cells to redirect NK cells to cancer cells in the treatment of solid tumors.
New Fields, New Opportunities and New Challenges: Circularly Polarized Multiple Resonance Thermally Activated Delayed Fluorescence Materials
Authors: Xu Yincai , Wang Qingyang , Song Xiaoxian , Wang Yue , Li Chenglong
Published: December 2022

Circularly polarized luminescence (CPL) materials that concurrently exhibit high efficiency and narrowband emission are extremely promising applications in 3D and wide color gamut display. By merging the CPL optical property and multiple resonance (MR) induced thermally activated delayed fluorescence (TADF) characteristic into one molecule, a new strategy, namely CP‐MR‐TADF, is proposed to generate organic emitters with CPL activity, TADF and narrowband emission. High‐performance red, green and blue CP‐MR‐TADF emitters have been developed following this strategy. Herein, the present status and progress of CP‐MR‐TADF materials in the field of organic light‐emitting diodes (OLEDs) is summarized. Finally, for this rapidly growing new research field, the future opportunities are forecasted and the present challenges are discussed.
A Enamide‐Based Diastereoselective Synthesis of Isoindolo[2,1‐a]quinolin‐11(5H)‐ones with Three Contiguous Stereogenic Centers
Authors: Halaczkiewicz Miro , Kelm Harald , Manolikakes Georg
Published: December 2022

A stereoselective synthesis of isoindolo[2,1‐a]quinolin‐11(5H)‐ones containing three contiguous stereogenic centers is described. This Lewis‐acid mediated reaction of enamides with N‐aryl‐acylimines affords the desired fused heterocyclic isoindolinones in high yields and diastereoselectivities. Scope and limitations of this method are discussed. The stereochemical outcome of this transformation indicates a stepwise reaction pathway.
Synthesis and Properties of Bis(naphthofuran)‐Fused [7]Helicene Derivatives
Authors: Hashmi Yuttawat , Thongpanchang Tienthong
Published: December 2022

Novel benzo[1,2‐b:4,3‐b′]dinaphthofuran (oxa[7]helicene) with various substituents in the central ring were designed and successfully synthesized based on the late stage central ring formation strategy from naphthofuranoneby using an efficient McMurry coupling or Friedel‐Crafts acylation. The photochemical properties of helicenes were evaluated by UV‐Visible absorption spectroscopy and fluorescence spectroscopy, while electrochemical behaviour including their energy profile were investigated by cyclic voltammetry and DFT calculations. According to the computational study, substituents on the central ring could influence both electron delocalization and MO distribution of oxa[7]helicenes resulting in the change in charge transporting ability. In comparison to the parent carbo[7]helicene, the furan unit in conjunction with substituents on helical system caused the bathochromic shift with different absorption pattern and exhibited higher fluorescence quantum yield (ϕf up to 0.63). These new materials showed promising characteristics in optoelectronic application.
Wearable and Flexible All‐Solid‐State Supercapacitor Based on MXene and Chitin
Authors: Kasprzak Dawid , Mayorga-Martinez Carmen C. , Alduhaish Osamah , Pumera Martin
Published: December 2022

Biopolymer‐based materials have recently received great interest as potential components for wearable energy‐storage devices. They can offer attractive and valuable properties such as renewability, biocompatibility, thermal and chemical stability, flexibility, durability, and biodegradability. Herein, a wearable and flexible all‐solid‐state supercapacitor that uses chitin as a biocompatible scaffold for integrating all device components, such as electrodes and an electrolyte, is developed. Chitin provides mechanical stability to electrode materials and supports the ionic liquid‐based gel electrolyte, and it also acts as a bonding agent to integrate all those components. Additionally, titanium carbide MXene is used as an active material for the proposed power source device. The MXene/chitin‐based all‐solid‐state supercapacitor exhibits impressive electrochemical performance, showing outstanding electrode conductivity, high capacitance, low internal resistance, high power density, and long‐term cycling stability. Moreover, it provides highly desired features concerning wearable devices, that is, excellent flexibility and mechanical strength under bending deformations, as well as sustainability and biodegradability. As a proof of concept, the MXene/chitin‐base device is applied for powering an electronic gadget. Herein, an important step is represented toward power‐efficient, wearable, and sustainable energy‐storage devices.
The Cardiff Self‐Injury Inventory (English version): Convergent validity and psychometric properties
Authors: Snowden Robert J. , Tiley Olivia , Gray Nicola S.
Published: December 2022

Background and Aims

The Cardiff Self‐Injury Inventory (CSII) is a short (1 min), relatively nonintrusive, measure of previous self‐injury behaviors written in English. It measures self‐injury with suicidal intent and without such intent, covers actions versus thoughts, and has two time periods (lifetime vs recent [defined as the last 3 months]). The study aimed to examine its psychometric properties and its relationship to more well‐established measures.

Methods

A UK community sample of 184 participants completed the CSII and two other measures of self‐harming (Deliberate Self‐Harm Inventory [DSHI] and Suicidal Behaviors Questionnaire–Revised [SBQ‐R]) in March 2020–May 2020. Fifty participants also repeated these measurements 1–2 weeks later.

Results

The CSII showed strong psychometric properties with internal reliability of 0.87 and a test–retest of 0.82. The subscales also showed strong psychometric properties. The CSII showed strong concurrent validity to the other measures of self‐injury (SBQ‐R, r = 0.70; DSHI, r = 0.81). A factor analysis supported the idea that there are two distinct components to the overall CSII score arising due to the distinction between suicidal and nonsuicidal behaviors.

Conclusion

The CSII has good psychometric properties in this population and can be used as a fast, nonintrusive, measure of different self‐injurious behaviors for clinical or research purposes.
Antibacterial and biocompatible polyaniline‐doped titanium oxide layers
Authors: Ali Aya , Chowdhury Sheetal , Carr Mary A. , Janorkar Amol V. , Marquart Mary , Griggs Jason A. , Bumgardner Joel D. , Roach Michael D.
Published: December 2022

Titanium anodization has been shown to produce crystalline oxides exhibiting photocatalytic reactions that form reactive oxygen species (ROS) when exposed to UV light. The ROS subsequently attack bacteria cells, and thus reduce bacteria attachment on titanium implant surfaces. Polyaniline (PANI) is a conductive polymer that has shown antibacterial properties when electropolymerized onto titanium. Our research group hypothesized the addition of PANI to crystalline titanium oxide surfaces would increase the available free electrons and thus increase photocatalytic activity (PCA). This research led to the development of a novel single‐step anodization approach for PANI doping crystalline titanium oxide layers. The objective of the present study was to determine the proper aniline electrolyte concentration needed to maximize the PCA and reduce bacterial attachment on the formed oxides. Aniline concentrations up to 1 M were added into a 1 M sulfuric acid electrolyte. The formed oxides exhibited increased PANI surface coverage but decreased anatase and rutile crystalline titanium oxide phase formation with increasing aniline electrolyte concentrations. Despite exhibiting the lowest levels of anatase and rutile formation, the 0.75 M and 1 M aniline oxides with the greatest PANI surface coverage also exhibited the highest PCA levels. 1 M aniline oxides showed significantly higher PCA under UVA irradiation compared to oxides formed from aniline concentrations up to 0.5 M (p < 0.001). 0.75 M aniline oxides exhibited significant reductions in Staphylococcus aureus attachment with or without UVA irradiation compared to control oxides without PANI. MTT and live/dead assays confirmed cytocompatibility and nearly 100% cell viability for the PANI doped oxides.
Cyclo‐glycylproline attenuates hydrogen peroxide‐induced cellular damage mediated by the MDM2‐p53 pathway in human neural stem cells
Authors: Murotomi Kazutoshi , Kagiwada Harumi , Hirano Kazumi , Yamamoto Shoko , Numata Noriaki , Matsumoto Yo , Kaneko Hidekazu , Namihira Masakazu
Published: December 2022

Cyclo‐glycylproline (cGP), a cyclic dipeptide containing a condensation bond between glycine and proline, is produced by the cyclization of the N‐terminal tripeptide of insulin‐like growth factor‐1. Previous studies have shown that cGP administration exerts a neuroprotective effect and enhances the regenerative ability in rats with ischemic brain injury. The efficacy of cGP is medicated by regulating the bioavailability of insulin‐like growth factor‐1 (IGF‐1), however, the molecular mechanisms underlying the neuroprotective effects of cGP on brain damage remains to be elucidated. In the current study, we investigated the cGP‐mediated molecular mechanism in human fetal neural stem cells (hfNSCs) exposed to oxidative stress, which is a key factor affecting the development of several brain diseases, including traumatic brain injury and Parkinson's disease. We found that cGP treatment attenuated oxidative stress‐induced cell death in cultured hfNSCs in a dose‐dependent manner. Transcriptome analysis revealed that under oxidative stress conditions, p53‐mediated signaling was activated, accompanied by upregulation of mouse double minute 2 homolog (MDM2), a p53‐specific E3 ubiquitin ligase, in cGP‐treated hfNSCs. By using a comprehensive protein phosphorylation array, we found that cGP induced the activation of Akt signaling pathway, which enhanced the expression of MDM2, in hfNSCs exposed to oxidative stress. Moreover, the MDM2 inhibitor nutlin‐3 inhibited the protective effect of cGP on oxidative stress‐induced cell death and apoptosis. Therefore, cGP attenuates oxidative stress‐induced cell death mediated by the interplay between IGF‐1 signaling and the MDM2‐p53 pathway in human NSCs. We revealed the molecular mechanism underlying cGP‐induced neuroprotective properties in a model of brain damage.
Adaptive tracking control for a class of nonlinear systems with input dead‐zone and actuator failure
Authors: Lei Ming , Chen Weimin , Wang Lanning
Published: December 2022

In this paper, the adaptive tracking problem for a class of strictly feedback nonlinear time‐delay systems with output constraints, actuator failures, and input dead zones is studied. First, in the design of controller, the absolute value function and integral term are introduced into the candidate functions to deal with nonlinear factors and distributed time‐varying delays in the system. In addition, an adaptive neural network controller is designed to ensure the stability of the controlled system, and the system tracking error can converge to the origin without violating the constraints. Finally, simulation results verify the feasibility of the proposed control strategy.
Development of a new iterative method and its convergence analysis for nonlinear fourth‐order boundary value problems arising in beam analysis
Authors: Tomar Saurabh , Singh Mehakpreet , Ramos Higinio , Wazwaz Abdul‐Majid
Published: December 2022

In this study, an effective iterative technique based on Green's function is proposed to solve a nonlinear fourth‐order boundary value problem (BVP) with nonlinear boundary conditions, which models an elastic beam. An iterative Green's function approach and a shooting method are integrated in the proposed method. The mathematical derivation is further supported by examining the convergence analysis of the proposed method. The iterative method rapidly generates a convergent series solution to the given problem. The proposed method has many advantages over existing methods: (a) A rapid convergence and (b) the ability to generate a highly accurate series solution with just a few iterations for complex problems arising in elastic beam. To demonstrate the applicability and effectiveness of the proposed method, four numerical examples are tested. The numerical results show that our methodology delivers more efficient results compared to other existing methods.
Technical note: Temporal and thermal stability of optical response for silicone‐based 3D radiochromic dosimeters
Authors: Valdetaro Lia Barbosa , Jensen Morten Bjørn , Muren Ludvig Paul , Skyt Peter Sandegaard , Petersen Jørgen Breede Baltzer , Balling Peter
Published: December 2022

Background

Radiochromic silicone‐based dosimeters are flexible 3D dosimeters, which at appropriate concentration of leucomalachite green (LMG) and curing agent are dose‐rate independent for clinical photon beams. However, their dose response is based on chemical processes that can be influenced by temporal and thermal conditions, impacting measurement stability.

Purpose

The aim of this study was to investigate the temporal stability of the dose response of radiochromic dosimeters for different curing times and post‐irradiation storage temperatures.

Methods

Six cylindrical dosimeters (5 cm diameter, 5 cm length) were produced in a single batch and separated into two groups that were irradiated 72 and 118 h after production. The same photon plan, consisting of two 10 × 1.6 cm2 opposing fields, was delivered to all dosimeters. After irradiation, the dosimeters were separated into three groups, stored at 5°C, 15°C, and 20°C, and read out for five consecutive days.

Results

Storage temperature influenced the measurement stability, and changes in the optical response with time differed between irradiated and non‐irradiated parts of the dosimeters. The relative change between signal and background was greater than 10% for all measurements performed 24 h or more after irradiation, except for dosimeters stored at 5°C, which changed by 2%–5% after 24 h. The dosimeter temporal stability was not influenced by curing time.

Conclusions

For room temperature storage (15°C and 20°C), readout should take place as soon as possible after irradiation since the background color increased rapidly for both curing times (72 and 118 h), whereas the dosimeters are stored at 5°C, readout can be performed up to 24 h after.
Silent active device tracking for MR‐guided interventional procedures
Authors: Stehning Christian , Krueger Sascha , Weiss Steffen , Smink Jouke , Koken Peter , Hindricks Gerhard , Jahnke Cosima , Paetsch Ingo
Published: December 2022

Purpose

To evaluate a silent MR active catheter tracking sequence that allows conducting catheter interventions with low acoustic noise levels.

Methods

To reduce the acoustic noise associated with MR catheter tracking, we implemented a technique previously used in conventional MRI. The gradient waveforms are modified to reduce the sound pressure level (SPL) and avoid acoustic resonances of the MRI system. The efficacy of the noise reduction was assessed by software‐predicted SPL and verified by measurements. Furthermore, the quality of the catheter tracking signal was assessed in a phantom experiment and during interventional cardiovascular MRI sessions targeted at isthmus‐related flutter ablation.

Results

The maximum measured SPL in the scanner room was 104 dB(A) for real‐time imaging, and 88 dB(A) and 69 dB(A) for conventional and silent tracking, respectively. The SPL measured at different positions in the MR suite using silent tracking were 65–69 dB(A), and thus within the range of a normal conversation. Equivalent signal quality and tracking accuracy were obtained using the silent variant of the catheter tracking sequence.

Conclusion

Our results indicate that silent MR catheter tracking capabilities are identical to conventional catheter tracking. The achieved acoustic noise reduction comes at no penalty in terms of tracking quality or temporal resolution, improves comfort and safety, and can overcome the need for MR‐compatible communication equipment and background noise suppression during the actual interventional procedure.
The management challenges of a case with Flupentixol‐induced neuroleptic malignant syndrome
Authors: Elyasi Forouzan , sadati Seyedehnasibeh , Heydari Fateme
Published: December 2022

Background

Neuroleptic malignant syndrome (NMS) is a rare and life‐threatening reaction. The incidence rate of NMS has dropped because of the higher use of atypical antipsychotics, compared with the typical ones. The mortality rate in patients taking injectable antipsychotics has been also by 38%.

Aim

Here, a case developing the NMS symptoms following Flupentixol (FPX) use was reported.

Case presentation

The patient was a 46‐year‐old man with the history of schizoaffective disorder (SAD) and recently on six‐weekly doses of long‐acting (LA) typical antipsychotic drugs. He was referred with a fever, sweating, a food intolerance, mutism, and disorientation in 2019. He was presented with generalized rigidity, negativism, and neck stiffness. The patient's initial creatine phosphokinase (CPK) level was 1476 IU/L, which gradually elevated to 3997 IU/L on Day 26. NMS was further diagnosed, in accordance with the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM‐5) criteria, and the score 9+ in the Naranjo Algorithm as the adverse drug reaction probability scale. Afterward, the patient was treated with bromocriptine at a dose of 5 mg 3 times a day, which progressively reached a maximum of 50 mg. He experienced sepsis and resistant respiratory infection several times. The case was finally discharged after 66 days of hospitalization, with a high level of consciousness, but limited verbal communication, in a fever‐free condition with the oral administration of bromocriptine and lorazepam.

Conclusion

In conclusion, there were suggestions for the management challenges of NMS in patients receiving LA injectable antipsychotic agents.
A systematic study on weak Galerkin finite element method for second‐order parabolic problems
Authors: Deka Bhupen , Kumar Naresh
Published: December 2022

In the present work, we have described a systematic numerical study on weak Galerkin (WG) finite element method for second‐order linear parabolic problems by allowing polynomial approximations with various degrees for each local element. Convergence of both semidiscrete and fully discrete WG solutions are established in and norms for a general WG element , where , and are arbitrary integers. The fully discrete space–time discretization is based on a first order in time Euler scheme. Numerical experiments are reported to justify the robustness, reliability and accuracy of the WG finite element method.
Repositioning urban bias: Non‐state providers' use of spatialised networks in Bangladesh
Authors: Badruzzaman Aeshna
Published: January 2023

Urban bias theory predicts urban areas of developing countries receive disproportionately more resources than rural areas due to their concentration of numerically large, politically important “vote banks.” This has not been the case in Bangladesh. This study finds that this variation occurs due to non‐state providers (NSPs) changing the landscape of resource allocation. Operating on the premise that state control leads to more services in urban areas, urban bias fails to account for NSPs as critical service providers. Employing a grounded theory strategy to explore urban‐rural dynamics in service provision and to build on urban bias theory, this research highlights interactions between state and non‐state actors. It argues that spatialized political networks, networks of formal and informal leadership more difficult to access in urban areas, influence the locality of service provision. Though NSPs recognize increased need in urban areas of Bangladesh, their interventions in those areas remain peripheral due to differing structures of government accountability and differing levels of community acceptance facilitating these networks. The need for NSPs to adapt their activities to restrictive governance mechanisms reflects the changing space for NSPs in the context of semi‐democratic regimes.
“Not‐so‐popular” orthogonal pairs in genetic code expansion
Authors: Andrews Joseph , Gan Qinglei , Fan Chenguang
Published: December 2022

During the past decade, genetic code expansion has been proved to be a powerful tool for protein studies and engineering. As the key part, a series of orthogonal pairs have been developed to site‐specifically incorporate hundreds of noncanonical amino acids (ncAAs) into proteins by using bacteria, yeast, mammalian cells, animals, or plants as hosts. Among them, the pair of tyrosyl‐tRNA synthetase/tRNATyr from Methanococcus jannaschii and the pair of pyrrolysyl‐tRNA synthetase/tRNAPyl from Methanosarcina species are the most popular ones. Recently, other “not‐so‐popular” orthogonal pairs have started to attract attentions, because they can provide more choices of ncAA candidates and are necessary for simultaneous incorporation of multiple ncAAs into a single protein. Here, we summarize the development and applications of those “not‐so‐popular” orthogonal pairs, providing guidance for studying and engineering proteins.
High‐yield recombinant bacterial expression of 13C‐, 15N‐labeled, serine‐16 phosphorylated, murine amelogenin using a modified third generation genetic code expansion protocol
Authors: Buchko Garry W. , Zhou Mowei , Vesely Cat Hoang , Tao Jinhui , Shaw Wendy J. , Mehl Ryan A. , Cooley Richard B.
Published: December 2022

Amelogenin constitutes ~90% of the enamel matrix in the secretory stage of amelogenesis, a still poorly understood process that results in the formation of the hardest and most mineralized tissue in vertebrates—enamel. Most biophysical research with amelogenin uses recombinant protein expressed in Escherichia coli. In addition to providing copious amounts of protein, recombinant expression allows 13C‐ and 15N‐labeling for detailed structural studies using NMR spectroscopy. However, native amelogenin is phosphorylated at one position, Ser‐16 in murine amelogenin, and there is mounting evidence that Ser‐16 phosphorylation is important. Using a modified genetic code expansion protocol we have expressed and purified uniformly 13C‐, 15N‐labeled murine amelogenin (pS16M179) with ~95% of the protein being correctly phosphorylated. Homogeneous phosphorylation was achieved using commercially available, enriched, 13C‐, 15N‐labeled media, and protein expression was induced with isopropyl β‐D‐1‐thiogalactopyranoside at 310 K. Phosphoserine incorporation was verified from one‐dimensional 31P NMR spectra, comparison of 1H‐15N HSQC spectra, Phos‐tag SDS PAGE, and mass spectrometry. Phosphorus‐31 NMR spectra for pS16M179 under conditions known to trigger amelogenin self‐assembly into nanospheres confirm nanosphere models with buried N‐termini. Lambda phosphatase treatment of these nanospheres results in the dephosphorylation of pS16M179, confirming that smaller oligomers and monomers with exposed N‐termini are in equilibrium with nanospheres. Such 13C‐, 15N‐labeling of amelogenin with accurately encoded phosphoserine incorporation will accelerate biomineralization research to understand amelogenesis and stimulate the expanded use of genetic code expansion protocols to introduce phosphorylated amino acids into proteins.