bluuebunny/crossref_metadata_2025 huggingface dataset:
Physicochemical Characterization of Pectin‐Gelatin Biomaterial Formulations for 3D Bioprinting
Authors: Lapomarda Anna , Cerqueni Giorgia , Geven Mike A. , Chiesa Irene , De Acutis Aurora , De Blasi Matteo , Montemurro Francesca , De Maria Carmelo , Mattioli‐Belmonte Monica , Vozzi Giovanni
Published: June 2021

Developing biomaterial formulations with specific biochemical characteristics and physical properties suitable for bioprinting of 3D scaffolds is a pivotal challenge in tissue engineering. Therefore, the design of novel bioprintable formulations is a continuously evolving research field. In this work, the authors aim at expanding the library of biomaterial inks by blending two natural biopolymers: pectin and gelatin. Cytocompatible formulations are obtained by combining pectin and gelatin at different ratios and using (3‐glycidyloxypropyl)trimethoxysilane (GPTMS) as single crosslinking agent. It is shown that the developed formulations are all suitable for extrusion‐based 3D bioprinting. Self‐supporting scaffolds with a designed macroporosity and micropores in the bioprinted struts are successfully obtained by combining extrusion‐based bioprinting and freeze‐drying. The presence of gelatin in these formulations allows for the modulation of porosity, of water uptake and of scaffold stiffness in respect to pure pectin scaffolds. Results demonstrate that these new biomaterial formulations, processed with this specific approach, are promising candidates for the fabrication of tissue‐like scaffolds for tissue regeneration.
Insights in the Thermal Volume Transition of Poly(2‐oxazoline) Hydrogels
Authors: Segiet Dominik , Stockmann Annika , Sadowski Jan , Katzenberg Frank , Tiller Joerg C.
Published: June 2021

Polymers with a lower or an upper critical solution temperature (LCST or UCST) can precipitate in a very narrow temperature range. Cross‐linking of such polymers and adding them to suited solvent results in smart gels that are capable of greatly changing their dimensions with changing temperature. This transition occurs very often in a broad temperature range, which limits the applicability of smart materials. To shed some light into the design of thermo‐responsive hydrogels with a narrow phase transition, poly(2‐ethyl‐2‐oxazoline) (PEtOx), poly(2‐isopropyl‐2‐oxazoline), and statistical copolymers of 2‐butyl‐2‐oxazoline and 2‐ethyl‐2‐oxazoline, respectively, are synthesized and the concentration‐dependent cloud point temperatures (Tcp) of the free polymers in aqueous media are determined in relation to the thermo‐responsive swelling behavior of the respective hydrogels. A narrow thermal transition of the hydrogels can only be achieved when the Tcp of the free polymers in water is independent on the concentration. Aqueous salt solutions can render even PEtOx into a concentration independent LCST polymer. However, this salt effect does not work for hydrogels.
A Hydrothermal Strategy to Fabricate Carbons‐Doped Polyaniline Hydrogels with Separation‐Free for Flexible All‐Solid‐State Supercapacitors
Authors: Chen Peng , Yang Jianxiao , Guo Kunkun
Published: June 2021

Carbon‐doped polyaniline (PANI) hydrogels (PFMH) are fabricated by a facile hydrothermal strategy that aniline monomers are in situ polymerized on mesoporous carbons (MC) and carbon fibers (CF) with phytic acids as both cross‐linkers and dopants. Likewise, MC and CF can provide heterogeneous active sites to initiate the polymerization, acting as the skeletons within multi‐dimensional interconnected channel structures. First‐principles density functional theory calculations show that the interactions between different bases of PANI and MC/CF are all adsorptive prone to possess the separation‐free structure, but the adsorptive interactions between different bases and MC are significantly stronger than those of CF. Therefore, MC would be tightly anchored by PANI chains to improve the mechanical strength, while CF can provide favorable conductivity interconnected network skeletons. As such, the electrical conductivity and fracture strength of PFMH are measured high up to 13.32 S m−1 and 233.4 kPa at the fracture deformation (54.7%), respectively. PFMH as supercapacitor (SC) electrodes can achieve the gravimetric specific capacitance of 637.9 F g−1 at 1 A g−1. In particular, the as‐fabricated flexible all‐solid‐state SCs can maintain normal operation under various deformation conditions, showing the great potential to become an advanced power device for wearable electronics.
UV‐ and Thermally‐Active Bifunctional Gelators Create Surface‐Anchored Polymer Networks
Authors: Pandiyarajan Chinnayan Kannan , Genzer Jan
Published: June 2021

A versatile one‐step synthesis of surface‐attached polymer networks using small bifunctional gelators (SBG), namely 4‐azidosulfonylphenethyltrimethoxysilane (4‐ASPTMS) and 6‐azidosulfonylhexyltriethoxysilane (6‐ASHTES) is reported. A thin layer (≈200 nm) of a mixture comprising ≈90% precursor polymer and 10% of 4‐ASPTMS or 10% 6‐ASHTES on a silicon wafer is deposited. Upon UV irradiation (≈l–254 nm) or annealing (>100 °C) layers, sulfonyl azides (SAz) release nitrogen by forming singlet and triplet nitrenes that concurrently react with any C─H bond in the vicinity resulting in sulfonamide crosslinks. Condensation among tri‐alkoxy groups (i.e., methoxy or ethoxy) in bulk connects the SBG units, which completes the crosslinking. Concurrently, when such functionalities react with hydroxyl groups at the surface, which enable the covalent attachment of the crosslinked polymer chains. A systematic investigation on reaction mechanism and gel formation using spectroscopic ellipsometry (SE) and Fourier‐transform infrared spectroscopy in the attenuated total reflection mode (FTIR‐ATR) is performed. Analogous thermally initiated gelation for both 4‐ASPTMS and 6‐ASHTES is found. The 6‐ASHTES is UV inactive at ≈l–254 nm, while the 4‐ASPTMS is active and forms gels. The difference is attributed to the aromatic nature of 4‐ASPTMS that absorb UV light at ≈l–254 nm due to π–π* transition.
Macrocyclic Photoinitiator Based on Prism[5]arene Matching LEDs Light with Low Migration
Authors: Song Qiuyan , Shang Kun , Xue Tanlong , Wang Zongcheng , Pei Di , Zhao Shuai , Nie Jun , Chang Yincheng
Published: June 2021

In this work, a naphthalene‐based macrocycle prism[5]arene (NP5OCH3) is developed as a novel kind of photoinitiator. When NP5OCH3 is irradiated under light, the bond between methylene and naphthalene can be quickly broken owning to the existence of ring tension. The macrocycle is cleaved to linear oligomer biradicals, which can effectively initiate the free radical photopolymerization of acrylate monomers. Compared with conventional photoinitiators, NP5OCH3 has strong light absorption in the wavelength range of 365–405 nm, so it can well match the environment‐friendly light‐emitting diodes (LEDs) light source to realize highly efficient initiation. In addition, there is no small molecule fragment generated during NP5OCH3 fracture, and the resulted linear oligomer biradicals can be immobilized in the polymer after initiating polymerization, so NP5OCH3 photoinitiators show much lower migration rate and cytotoxicity. Cleavable macrocycle prismarene may provide a new idea for the design of safe and efficient photoinitiators matching long wavelength light.
Piston Compression of Semiflexible Ring Polymers in Channels
Authors: Cifra Peter , Bleha Tomáš
Published: June 2021

Molecular simulations in nanochannels are used to explore the compression elasticity of ring polymers of stiffness (persistence length) similar to DNA. By combination with the parallel data for linear polymers, the effect of chain topology on their compression behavior is assessed. The results show that the ring polymers are much less bendable at longitudinal compression than the linear analogs. The chain span of linear polymers is continuously reduced at compression, whereas in ring polymers, an abrupt decrease of the span is observed. The simulation data elucidate this phenomenon as the buckling of a ring polymer into the double‐folded hairpin. The shrinking ratio of sizes of the ring and linear chains shows a complex behavior much differing from the existing reports. The force–displacement functions for chains of both topologies at moderate confinement are very well accounted for by the mean‐field Flory scheme. The theory predicts the difference in the mechanical stiffness of the ring and linear polymers in qualitative agreement with the simulation data. These findings are relevant to the compression behavior of semiflexible ring polymers under spatial constraints such as in nanofluidic experiments, disordered media, or cellular environment.
Sensorimotor Cough Dysfunction Is Prevalent and Pervasive in Progressive Supranuclear Palsy
Authors: Borders James C. , Sevitz Jordanna S. , Curtis James A. , Vanegas‐Arroyave Nora , Troche Michelle S.
Published: June 2021

Background

Pneumonia, a leading cause of death in progressive supranuclear palsy (PSP), results from progressive and pervasive deficits of airway protection, including both cough and swallowing dysfunction. Cough protects the airway by expelling aspirate and may be an important therapeutic target to protect against pneumonia in the presence of dysphagia. However, cough has not been objectively characterized in PSP or compared to other common forms of parkinsonism, such as Parkinson's disease (PD).

Objective

The purpose of this study was to examine voluntary and reflex cough function in PSP, as compared to patients with PD matched for disease duration.

Methods

Twenty‐six patients with PSP and 26 with PD completed voluntary and reflex cough testing via spirometry. Linear mixed effects models examined comparisons between groups and within cough types across cough sensory and motor outcomes.

Results

Patients with PSP demonstrated significantly reduced cough motor function compared to PD, specifically reduced peak expiratory flow rate (P < 0.001), cough expiratory volume (P < 0.001), and cough inspiratory volume (P = 0.008). Both groups showed similar reflex cough thresholds (P = 0.694), but PSP demonstrated an increased perception of cough stimuli (P = 0.041).

Conclusions

These findings suggest that sensorimotor cough dysfunction is prevalent in PSP, and cough motor deficits, in particular, are worse in PSP than in PD. These deficits likely contribute to the pathogenesis of pneumonia in PSP. Therefore, cough should be integrated into assessments of airway protection and considered as a therapeutic target to potentially reduce adverse health events and improve quality of life in this population. © 2021 International Parkinson and Movement Disorder Society
Anterolateral thigh osteomyocutaneous flap in head and neck: Lessons learned
Authors: Cannady Steven B. , Mady Leila J. , Brody Robert M. , Shimunov David , Newman Jason G. , Chalian Ara C. , Rajasekaran Karthik A. , Sheth Neil P. , Shanti Rabie M.
Published: June 2021

Background

Concerns regarding iatrogenic femur fracture may deter adoption of the anterolateral thigh osteomyocutaneous (ALTO) flap as an alternative reconstructive technique for large composite defects of the head and neck. We describe the evolution of our experience with this flap and the lessons learned in femur management.

Methods

Records from a prospective database (July 2009–January 2020) were reviewed to identify patients with composite osseous free tissue reconstructions. Venous thromboembolic events (VTE), femur fracture, estimated blood loss (EBL), procedure time, blood transfusions, and length of stay (days) were compared for ALTO flaps prior to and after the adoption of intramedullary fixation protocol.

Results

ALTO represented 10.5% (n = 23) of total osseus (n = 219) flaps. For large composite reconstructions with either ALTO flap, double flap (n = 2), or subscapular mega flaps (n = 14), ALTO flaps were most frequently used (59%, n = 23/59). There were no differences in operative time prior to and after implementation of prophylactic fixation [median (range): 5.4 (1.7–19.2) vs. 5.8 (1.7–15.0), p = .574]. Additionally, there were no differences in VTE, femur fracture, EBL, blood transfusion, or length of stay (p > .05) with adoption of prophylactic intramedullary fixation.

Conclusions

The ALTO flap represents a useful tool to consider in the armamentarium of reconstructive options for large through and through defects of the head and neck. In our experience, the ALTO flap is a reasonable alternative to subscapular or double flap reconstructions and especially in the setting of unusable fibular flaps or when bone need exceeds that available from the scapula.
Technical Note: Multiple energy extraction techniques for synchrotron‐based proton delivery systems may exacerbate motion interplay effects in lung cancer treatments
Authors: Younkin James E. , Morales Danairis Hernandez , Shen Jiajian , Ding Xiaoning , Stoker Joshua B. , Yu Nathan Y. , Sio Terence T. , Daniels Thomas B. , Bues Martin , Fatyga Mirek , Schild Steven E. , Liu Wei
Published: June 2021

Purpose

The multiple energy extraction (MEE) delivery technique for synchrotron‐based proton delivery systems reduces beam delivery time by decelerating the beam multiple times during one accelerator spill, but this might cause additional plan quality degradation due to intrafractional motion. We seek to determine whether MEE causes significantly different plan quality degradation compared to single energy extraction (SEE) for lung cancer treatments due to the interplay effect.

Methods

Ten lung cancer patients treated with IMPT at our institution were nonrandomly sampled based on a representative range of tumor motion amplitudes, tumor volumes, and respiratory periods. Dose‐volume histogram (DVH) indices from single‐fraction SEE and MEE four‐dimensional (4D) dynamic dose distributions were compared using the Wilcoxon signed‐rank test. Distributions of monitor units (MU) to breathing phases were investigated for features associated with plan quality degradation. SEE and MEE DVH indices were compared in fractionated deliveries of the worst‐case patient treatment scenario to evaluate the impact of fractionation.

Results

There were no clinically significant differences in target mean dose, target dose conformity, or dose to organs‐at‐risk between SEE and MEE in single‐fraction delivery. Three patients had significantly worse dose homogeneity with MEE compared to SEE (single‐fraction mean D5%‐D95% increased by up to 9.6% of prescription dose), and plots of MU distribution to breathing phases showed synchronization patterns with MEE but not SEE. However, after 30 fractions the patient in the worst‐case scenario had clinically acceptable target dose homogeneity and coverage with MEE (mean D5%–D95% increased by 1% compared to SEE).

Conclusions

For some patients with breathing periods close to the mean spill duration, MEE resulted in significantly worse single‐fraction target dose homogeneity compared to SEE due to the interplay effect. However, this was mitigated by fractionation, and target dose homogeneity and coverage were clinically acceptable after 30 fractions with MEE.
Feasibility of attenuation map alignment in pinhole cardiac SPECT using exponential data consistency conditions
Authors: Wells R Glenn , Clackdoyle Rolf
Published: June 2021

Purpose

Dedicated cardiac SPECT systems do not typically include an integrated CT scanner and thus attenuation correction requires registration of separately acquired transmission scans. Data consistency conditions are equations that express the redundancy between projections while taking into account the attenuation effects. This study assessed the feasibility of applying exponential data consistency conditions to rebinned pinhole projections for attenuation‐map registration in pinhole cardiac SPECT.

Methods

Simulations of an anthropomorphic computer phantom with three different tracer activity distributions were performed with and without clinical levels of noise in the projection data. The first activity distribution contained activity only within the myocardium which satisfied the assumptions of the data consistency conditions. The other two distributions violated these assumptions by adding background activity and uptake in the liver. Simulations included acquisitions with 360, 31, and 9 pinhole projections and detector pixel sizes of 0.75 and 2.5 mm. A metric based on the average difference between pairs of exponential projections was used to evaluate registration accuracy.

Results

When activity is restricted to the myocardium, the registration error was 3.0 mm for 31 noisy pinhole projections with a detector size of 2.5 mm. When activity is added to the background and the liver, a correction for the extra‐cardiac activity is needed but when applied, a registration error of 6.0 mm was achieved.

Conclusion

These results suggest that it may be feasible to use exponential data consistency conditions to register pinhole cardiac SPECT and CT transmission data.

Taxonomy: 8–6 (IM‐SPECT/Registration).
Technical Note: Range verification of pulsed proton beams from fixed‐field alternating gradient accelerator by means of time‐of‐flight measurement of ionoacoustic waves
Authors: Nakamura Yuta , Takayanagi Taisuke , Uesaka Tomoki , Unlu Mehmet Burcin , Kuriyama Yasutoshi , Ishi Yoshihiro , Uesugi Tomonori , Kobayashi Masanori , Kudo Nobuki , Tanaka Sodai , Umegaki Kikuo , Tomioka Satoshi , Matsuura Taeko
Published: June 2021

Purpose

Ionoacoustics is one of the promising approaches to verify the beam range in proton therapy. However, the weakness of the wave signal remains a main hindrance to its application in clinics. Here we studied the potential use of a fixed‐field alternating gradient accelerator (FFA), one of the accelerator candidates for future proton therapy. For such end, magnitude of the pressure wave and range accuracy achieved by the short‐pulsed beam of FFA were assessed, using both simulation and experimental procedure.

Methods

A 100 MeV proton beam from the FFA was applied on a water phantom, through the acrylic wall. The beam range measured by the Bragg peak (BP)‐ionization chamber (BPC) was 77.6 mm, while the maximum dose at BP was estimated to be 0.35 Gy/pulse. A hydrophone was placed 20 mm downstream of the BP, and signals were amplified and stored by a digital oscilloscope, averaged, and low‐pass filtered. Time‐of‐flight (TOF) and two relative TOF values were analyzed in order to determine the beam range. Furthermore, an acoustic wave transport simulation was conducted to estimate the amplitude of the pressure waves.

Results

The range calculated when using two relative TOF was 78.16 ± 0.01 and 78.14 ± 0.01 mm, respectively, both values being coherent with the range measured by the BPC (the difference was 0.5‒0.6 mm). In contrast, utilizing the direct TOF resulted in a range error of 1.8 mm. Fivefold and 50‐fold averaging were required to suppress the range variation to below 1 mm for TOF and relative TOF measures, respectively. The simulation suggested the magnitude of pressure wave at the detector exceeded 7 Pascal.

Conclusion

A submillimeter range accuracy was attained with a pulsed beam of about 21 ns from an FFA, at a clinical energy using relative TOF. To precisely quantify the range with a single TOF measurement, subsequent improvement in the measuring system is required.
Generation of material‐specific energy deposition kernels for kilovoltage x‐ray dose calculations
Authors: Heidarloo Nematollah , Aghamiri Seyed Mahmoud Reza , Saghamanesh Somayeh , Azma Zohreh , Alaei Parham
Published: June 2021

Purpose

Dose calculation of kilovoltage x rays used in Image‐Guided Radiotherapy has been investigated in recent years using various methods. Among these methods are model‐based ones that suffer from inaccuracies in high‐density materials and at interfaces when used in the kilovoltage energy range. The main reason for this is the use of water energy deposition kernels and simplifications employed such as density scaling in heterogeneous media. The purpose of this study was to produce and characterize material‐specific energy deposition kernels, which could be used for dose calculations in this energy range. These kernels will also have utility in dose calculations in superficial radiation therapy and orthovoltage beams utilized in small animal irradiators.

Methods

Water energy deposition kernels with various resolutions; and high‐resolution, material‐specific energy deposition kernels were generated in the energy range of 10–150 kVp, using the EGSnrc Monte Carlo toolkit. The generated energy deposition kernels were further characterized by calculating the effective depth of penetration, the effective radial distance, and the effective lateral distance. A simple benchmarking of the kernels against Monte Caro calculations has also been performed.

Results

There was good agreement with previously reported water kernels, as well as between kernels with different resolution. The evaluation of effective depth of penetration, and radial and laterals distances, defines the relationship between energy, material density, and the shape of the material‐specific kernels. The shape of these kernels becomes more forwardly scattered as the energy and material density are increased. The comparison of the dose calculated using the kernels with Monte Carlo provides acceptable results.

Conclusions

Water and material‐specific energy deposition kernels in the kilovoltage energy range have been generated, characterized, and compared to previous work. These kernels will have utility in dose calculations in this energy range once algorithms capable of employing them are fully developed.
Incoming Call
Authors: Ramaswamy Rahul Chakravarthi
Published: June 2021

A medical student describes his mother's journey with cancer, which led to a personal change in views on mortality to apply to future patient care.
Thermosetting resins from a tetra‐functional vinylbenzene compound possessing cyclic siloxane cores
Authors: Lee Hsuan‐Wei , Chang Li‐Ming , Liu Ying‐Ling
Published: June 2021

Cyclic siloxane is an attractive building block for incorporation of silicon‐containing units as well as their distinguished properties to polymer materials. This work reports the synthesis and characterization of a tetra‐functional vinylbenzene compound possessing cyclic siloxane cores (cD4‐4VB). Synthesis of cD4‐4VB is carried out using cD4‐4SiH as the reactive precursor and multiple‐step reactions, including hydrosilylation, deacetylation, and SN2 substitution. cD4‐4VB is an effective monomer for preparation of the corresponding cyclic silicon‐based thermosetting resins (CR‐cD4‐4VB). CR‐cD4‐4VB shows attractive film formability and good thermo‐mechanical properties, including a storage modulus of 2.0 GPa, a glass transition temperature of 282°C, a thermal stability above 400°C, a high char yield (at 800°C in nitrogen) of 55 wt%, and a dielectric constant of 3.12 at 10 GHz. This kind of resins have potential of application for halogen‐free flame retardants and high‐performance polymer films.
From Bulk to Nanoparticles: An Overview of Antiviral Materials, Its Mechanisms, and Applications
Authors: Rodrigues Isabella C. P. , Campo Kaio N. , Arns Clarice W. , Gabriel Laís P. , Webster Thomas J. , Lopes Éder S. N.
Published: June 2021

Infectious diseases caused by viruses are a global health concern and have become prominent in light of the recent COVID‐19 pandemic. Considering the limitations of drugs and prophylactic methods used in current medicine, antiviral materials are a useful strategy in preventing the spread of viruses and enhancing treatment efficiency. Thus, this review highlights the state‐of‐the‐art antiviral materials, describes the scientific landscape of the primary antiviral materials used based on bibliometric analysis, presents their mechanisms of action, and discusses their clinical applications. The mechanisms of action underlying the broad‐spectrum antiviral properties of metals, ceramics, polymers, and composites are also discussed. Polyanions, polycations, oxides, and metal‐based materials, from bulk to nanoparticles, have good potential in antiviral applications that may help prepare the world for future viral breakouts.
Silicon Nanowire Solar Cells with μc‐Si:H Absorbers for Radial Junction Devices
Authors: Dai Letian , Foldyna Martin , José Alvarez , Maurin Isabelle , Kleider Jean-Paul , Gacoin Thierry , Roca i Cabarrocas Pere
Published: June 2021

Silicon nanowire (SiNW) radial junction (RJ) solar cells using hydrogenated microcrystalline silicon (μc‐Si:H) as absorber material have been studied. Since 2013, the performance of such RJ devices has been limited by the low fill factor (FF) and open‐circuit voltage (VOC). Thanks to the use of n‐type hydrogenated microcrystalline silicon oxide (μc‐SiOx:H) as a bottom doped layer, the authors developed μc‐Si:H RJ solar cells with a FF of 69.7% and a VOC of 0.41 V yielding a power conversion efficiency of 4.1%, which is more than 40% higher than the previously published efficiency record of 2.9%. Herein, the role of n‐type μc‐SiOx:H in the improvement of FF is highlighted.
A Colossal Enhancement of Thermoelectric Performance of Monolayer SbAs Using Strain Engineering
Authors: Liu Lu , Peng Chengxiao , Feng Zhenzhen , Yan Yuli , Zhang Guangbiao , Wang Chao , Zhang Peiyu , Gu Qinfen
Published: June 2021

The effect of uniaxial strain on the thermoelectric (TE) conversion efficiency of puckered monolayer arsenic antimonide (SbAs) is explored based on the density function and Boltzmann transport equation (BTE) theories. The lattice thermal conductivity (κl) can be sharply lowered through tensile strain. Taking a + 3.25% tensile strain as an example, κl along the armchair (AC) direction at 300 K decreases almost three times than that without a strain, which is ascribed to the low phonon group velocity, large Grüneisen parameter, and high three‐phonon scattering phase space. The carrier effective mass decreases in imposing tensile strain monolayer SbAs and slightly suppresses the Seebeck coefficient; however, the electrical conductivity is improved due to the small effective mass and long relaxation time. Thus, power factor increases by 3.4 times under a  + 3.25% tensile at cm−2 compared with a SbAs monolayer without strain. Thereafter, the figure of merit in an n‐type SbAs monolayer with a tensile strain of +3.25% is eight times as large as that in SbAs without strain at 300 K along the AC direction. Furthermore, the maximum TE figure of merit is 1.85 for an n‐type SbAs monolayer with +3.25% strain at 800 K. This study paves a way toward improving the TE performance through strain engineering in the TE field.
Shotgun reconstruction in the hypercube
Authors: Przykucki Michał , Roberts Alexander , Scott Alex
Published: June 2021

Mossel and Ross raised the question of when a random coloring of a graph can be reconstructed from local information, namely, the colorings (with multiplicity) of balls of given radius. In this article, we are concerned with random 2‐colorings of the vertices of the ‐dimensional hypercube, or equivalently random Boolean functions. In the worst case, balls of diameter are required to reconstruct. However, the situation for random colorings is dramatically different: we show that almost every 2‐coloring can be reconstructed from the multiset of colorings of balls of radius 2. Furthermore, we show that for , almost every ‐coloring can be reconstructed from the multiset of colorings of 1‐balls.
Enhancing ferroelectric photovoltaic effect of BaTiO3 by the lateral interface
Authors: Wei Lijing , Li Changliang , Guan Li , Guo Jianxin
Published: June 2021

A large bandgap significantly suppress the development of ferroelectric photovoltaic (FE‐PV). The bandgap of BaTiO3 decreases to 1.49 eV from 2.46 eV by the formation of the lateral interface structure with BaO based on first principles calculations, which is beneficial to enhance the visible‐light adsorption of FE‐PV materials. The electronic structures of BaO/BaTiO3 show that the lateral interface plays a very important role. The conduction band minimum (CBM) and the valence band maximum (VBM) of BaO/BaTiO3 mainly originate from the Ba 6s states and the O 2p states in the interface of BaO/BaTiO3, respectively, revealing the strong lateral interface effect. In addition, the polarization of BaO/BaTiO3 decreases to 177.5 μC/cm2 from the 59.8 μC/cm2 of BaTiO3. The new mechanism provides a feasible way to reduce the bandgap of FE‐PV with the wide bandgap (>3.0 eV).
Continuous Monitoring Reveals Protective Effects of N‐Acetylcysteine Amide on an Isogenic Microphysiological Model of the Neurovascular Unit
Authors: Matthiesen Isabelle , Voulgaris Dimitrios , Nikolakopoulou Polyxeni , Winkler Thomas E. , Herland Anna
Published: June 2021

Microphysiological systems mimic the in vivo cellular ensemble and microenvironment with the goal of providing more human‐like models for biopharmaceutical research. In this study, the first such model of the blood‐brain barrier (BBB‐on‐chip) featuring both isogenic human induced pluripotent stem cell (hiPSC)‐derived cells and continuous barrier integrity monitoring with <2 min temporal resolution is reported. Its capabilities are showcased in the first microphysiological study of nitrosative stress and antioxidant prophylaxis. Relying on off‐stoichiometry thiol–ene–epoxy (OSTE+) for fabrication greatly facilitates assembly and sensor integration compared to the prevalent polydimethylsiloxane devices. The integrated cell–substrate endothelial resistance monitoring allows for capturing the formation and breakdown of the BBB model, which consists of cocultured hiPSC‐derived endothelial‐like and astrocyte‐like cells. Clear cellular disruption is observed when exposing the BBB‐on‐chip to the nitrosative stressor linsidomine, and the barrier permeability and barrier‐protective effects of the antioxidant N‐acetylcysteine amide are reported. Using metabolomic network analysis reveals further drug‐induced changes consistent with prior literature regarding, e.g., cysteine and glutathione involvement. A model like this opens new possibilities for drug screening studies and personalized medicine, relying solely on isogenic human‐derived cells and providing high‐resolution temporal readouts that can help in pharmacodynamic studies.
Creating a Dual‐Functional 2D Perovskite Layer at the Interface to Enhance the Performance of Flexible Perovskite Solar Cells
Authors: Long Caoyu , Huang Keqing , Chang Jianhui , Zuo Chuantian , Gao Yuanji , Luo Xin , Liu Biao , Xie Haipeng , Chen Zhihui , He Jun , Huang Han , Gao Yongli , Ding Liming , Yang Junliang
Published: June 2021

Flexible perovskite solar cells (f‐PSCs) have been attracting tremendous attention due to their potentially commercial prospects in flexible energy system and mobile energy system. Reducing the energy barriers and charge extraction losses at the interfaces between perovskite and charge transport layers is essential to improve both efficiency and stability of f‐PSCs. Herein, 4‐trifluoromethylphenylethylamine iodide (CF3PEAI) is introduced to form a 2D perovskite at the interface between perovskite and hole transport layer (HTL). It is found that the 2D perovskite plays a dual‐functional role in aligning energy band between perovskite and HTL and passivating the traps in the 3D perovskite, thus reducing energy loss and charge carrier recombination at the interface, facilitating the hole transfer from perovskite to the Spiro‐OMeTAD. Consequently, the photovoltaic performance of f‐PSCs is significantly improved, leading to a power conversion efficiency (PCE) of 21.1% and a certified PCE of 20.5%. Furthermore, the long‐term stability of f‐PSCs is greatly improved through the protection of 2D perovskite layer to the underlying 3D perovskite. This work provides an excellent strategy to produce efficient and stable f‐PSCs, which will accelerate their potential applications.
Recent Advances in the Pd‐Catalyzed Coupling of Arylhydrazines and Ammonium Salts via C−N Bond Cleavage
Authors: Tu Yongliang , Zhao Junfeng
Published: June 2021

Both arylhydrazines and quaternary ammonium salts are readily accessible or commercially available chemicals that show versatile reactivity in Pd‐catalyzed coupling reactions via C−N bond cleavage. A tremendous array of coupling reactions involving reaction partners such as organoborons, aryl silanes, alkenes, alkynes, arylation or alkylation reagents in C−H functionalization and carbonylation reactions are summarized, in which arylhydrazines or quaternary ammonium salts function as aryl or alkyl donors. This account mainly focuses on recent advances in Pd‐catalyzed coupling reactions with arylhydrazines or quaternary ammonium salts via C−N bond cleavage, including mechanistic elucidations.
Enantioselective Heck‐Matsuda Reactions: From Curiosity to a Game‐Changing Methodology
Authors: Oliveira Caio C. , Correia Carlos Roque Duarte
Published: June 2021

The enantioselective palladium‐catalyzed Heck arylation of olefins using arenediazonium salts is one of the last features in the evolution of a synthetic method known as the Heck‐Matsuda reaction. This personal account highlights the development of the enantioselective Heck‐Matsuda reaction in its initial stages, the challenges faced along the way, and the interesting findings that opened new synthetic opportunities, mainly from our laboratory, featuring the Heck‐Matsuda reaction as a central player in the synthesis of bioactive and functional molecules.
“I got to see, and I got to be a part of it”: How cued gesturing facilitates middle‐school students' explanatory modeling of thermal conduction
Authors: Mathayas Nitasha , Brown David E. , Lindgren Robb
Published: June 2021

Constructing causal mechanistic explanations of observable phenomena is a key science practice that is often challenging for students as most mechanisms involve interactions of unobservable entities and activities. In this study, we examined how gesturing with a computer simulation that depicts the molecular mechanism of thermal conduction supported middle‐school students in constructing causal mechanistic explanations. We designed a gesture‐augmented computer simulation in which students were cued to use hand gestures to control the simulation. These cued gestures represent core causal interactions of conduction and they prompt students to physically engage with the simulation in conceptually meaningful ways. In this study, we examined how 21 students used the simulation and explained thermal conduction in a semi‐structured interview, followed by a mixed‐methods analysis. Quantitative analysis shows that students moved toward articulating the canonical causal mechanistic explanation of thermal conduction using the simulation. Three representative cases were identified to explore how students' explanations were facilitated by cued gestures. The analysis shows two main ways the cued gestures supported all students in the study: (a) by helping them attribute causal agency to molecules rather than an entity called Heat, and (b) by reifying the core mechanism of molecular collisions in conduction. Furthermore, the case studies show how each student's unique ways of sensemaking impacted their gesture use. Implications for instruction with gestures and design of augmented environments are discussed.
PM2.5 induces endothelial dysfunction via activating NLRP3 inflammasome
Authors: Hu Tingting , Zhu Ping , Liu Yihai , Zhu Haoran , Geng Jin , Wang Bingjian , Yuan Guoliang , Peng Yuzhu , Xu Biao
Published: June 2021

PM2.5 (particulate matter <2.5 μm in diameter) is proven to contribute to the development of atherosclerosis. Endothelial cell dysfunction is the initial step of atherosclerosis. The underlying mechanisms of endothelial cell damage exposed to PM2.5 are still obscure. In our study, PM2.5 was administrated to C57BL/6 male mice by intranasal instillation for 2 weeks. Human umbilical vein endothelial cells (HUVECs) were also treated with PM2.5 to evaluate the adverse effect in vitro. The immunohistochemical staining of aortas showed that the expressions of proinflammatory cytokines and endothelial adhesion markers were significantly increased in PM2.5‐exposed mice than that in saline‐exposed mice. In vitro, PM2.5 could inhibit HUVECs viability and impair cell migration in a concentration‐dependent manner. Besides, PM2.5 exposure downregulated eNOS expression while upregulated reactive oxygen species (ROS) levels. Mechanistically, PM2.5 activated the NLRP3 inflammasome in HUVECs while knockdown of NLRP3 could effectively reverse the downregulation of eNOS expression and production of ROS after PM2.5 exposure. In summary, our data showed that PM2.5 could cause endothelial dysfunction, and probably via NLRP3 inflammasome activation.
Erk phosphorylation reduces the thymoquinone toxicity in human hepatocarcinoma
Authors: Zhang Bin , Ting Wei‐Jen , Gao Jun , Kang Zhan‐Fang , Huang Chih‐Yang , Weng Yi‐Jiun
Published: June 2021

Although enormous achievements have been made in targeted molecular therapies against hepatocellular carcinoma (HCC), the treatments can only prolong the life of patients with extrahepatic metastases. We evaluated thymoquinone (TQ), a compound from Nigella sativa Linn., for its anti‐cancer effect on SK‐Hep1 cells and HCC‐xenograft nude mice. TQ effectively triggered cell death    and activated p38 and extracellular signal‐regulated kinases (Erk) pathways up to 24 h after treatment in cells. TQ‐induced cell death was reversed by p38 inhibitor; however, it was enhanced by si‐Erk. The caspase3 activation and TUNEL assay revealed a stronger toxic effect upon co‐treatment with TQ and si‐Erk. Our study suggested that phosphorylation of p38 in SK‐Hep1 cells constituted the major factor leading to cell apoptosis, whereas phosphorylation of Erk led to drug resistance. Furthermore, TQ therapeutic effect was improved upon Erk inhibition in HCC‐xenograft nude mice. TQ could present excellent anti‐HCC potential under suitable p‐Erk inhibiting conditions.
LINC01234 aggravates cell growth and migration of triple‐negative breast cancer by activating the Wnt pathway
Authors: Xiao Feng , Jia Hongyao , Wu Di , Zhang Zhiru , Li Sijie , Guo Jianjin
Published: June 2021

Triple‐negative breast cancer (TNBC) is a common cancer with increasing incidence and mortality in female. Increasing studies have revealed that long noncoding RNAs (lncRNAs) are novel molecules regulating tumors. Long intergenic non‐protein coding RNA 1234 (LINC01234) has been demonstrated to function as an oncogene in several tumors. However, the role of LINC01234 in TNBC remains unelucidated. Herein, RT‐qPCR showed that LINC01234 expression was upregulated in both TNBC tissues and cell lines. Functionally, knockdown of LINC01234 suppressed proliferation, migration, invasion, epithelial‐mesenchymal transition (EMT) process, and promoted apoptosis in TNBC cells. Xenograft mouse models revealed that LINC01234 downregulation inhibited TNBC tumor growth in vivo. Furthermore, LINC01234 was transcriptionally elevated by Sp1 transcription factor (SP1) in TNBC cells. Mechanistically, LINC01234 interacted with miR‐525‐5p and miR‐525‐5p targeted MEIS2. Rescue assays manifested that MEIS2 overexpression rescued the cellular processes inhibited by silenced LINC01234. Moreover, we validated that LINC01234 regulated the activation of the Wnt pathway through modulating MEIS2 in TNBC cells. In conclusion, LINC01234 aggravated TNBC cell growth, migration, invasion and EMT by modulating the miR‐525‐5p/MEIS2 axis and activating the Wnt/β‐catenin signaling pathway.
Invertebrate zoogeomorphology: A review and conceptual framework for rivers
Authors: Mason Richard J. , Sanders Harry
Published: June 2021

Invertebrates are important sediment engineers, making up for their small body size with abundance and behavioral diversity. However, despite the recognized importance of invertebrates as sediment engineers in terrestrial and marine environments, zoogeomorphology in rivers has primarily considered larger taxa, such as fish and beaver. This article reviews the zoogeomorphic effects of invertebrates in freshwater habitats, with a focus on rivers. To better synthesize current zoogeomorphic research and to help guide future studies we build a conceptual model considering biotic (behavior, abundance, body size, life history, and species invasions) and abiotic (geophysical energy and sediment grain size) controls on the direction and magnitude of zoogeomorphology. We also incorporate invertebrate engineers into conceptual sediment entrainment models, to understand their geomorphic role in the context of hydraulic power and sediment size. We structure our review around invertebrate behavior as a key control on whether invertebrates have a sediment destabilizing or stabilizing impact. Invertebrate zoogeomorphic behavior are diverse; the majority of research concernsbioturbation, a result of locomotion, foraging, and burrowing behaviors by many taxa. Similarly, burrowing into bedrock by a caddisfly and non‐biting midge larvae promotesbioerosion. Attachment to the substrate, (e.g., silk nets by caddisfly larvae or byssal threads by some mussels) can stabilize sediment, providingbioprotection.Bioconstructions(e.g., caddisfly cases and mussel shells) may have either stabilizing or destabilizing effects depending on their density and abiotic context. Interactions between lotic invertebrates and fluvial processes are complex and understudied, requiring further research across a greater range of taxa, behaviors, and spatiotemporal scales.

This article is categorized under:

Water and Life > Nature of Freshwater Ecosystems

Water and Life > Conservation, Management, and Awareness
Theragnostic nanomotors: Successes and upcoming challenges
Authors: Vasantha Ramachandran Reshma , Bhat Ramray , Kumar Saini Deepak , Ghosh Ambarish
Published: June 2021

The idea of “fantastic voyagers” carrying out medical tasks within the human body has existed as part of popular culture for many decades. The concept revolved around a miniaturized robot that can travel inside the human body and perform complicated functions such as surgery, navigation of otherwise inaccessible biological environments, and delivery of therapeutics. Since the last decade, significant developments have occurred in this arena that are yet to enter mainstream biomedical practises. Here, we define the challenges to make this fiction into reality. We begin by chalking the journey from pills, nanoparticles, and then to micro‐nanomotors. The review describes the principles, physicochemical contexts, and advantages that micro‐nanomotors provide. The article then describes micro‐nanomotors' obstacles such as maneuverability, in vivo imaging, toxicity, and biodistribution.

This article is categorized under:

Diagnostic Tools > In Vivo Nanodiagnostics and Imaging

Nanotechnology Approaches to Biology > Nanoscale Systems in Biology
Correction to: Income Inequality, Socio-Economic Status, and Residential Segregation in Greater Cairo: 1986–2006
Authors: Mohamed Abdelbaseer A. , Stanek David
Published: June 2021

The original version of the book was published with incorrect figure 3.3. The chapter and book have been updated with the changes.
Two-loop leading-color helicity amplitudes for three-photon production at the LHC
Authors: Chawdhry Herschel A. , Czakon Michał , Mitov Alexander , Poncelet Rene
Published: June 2021

Abstract

We calculate all planar contributions to the two-loop massless helicity amplitudes for the process $$ q\overline{q} $$
q

q
¯

→ γγγ. The results are presented in fully analytic form in terms of the functional basis proposed recently by Chicherin and Sotnikov. With this publication we provide the two-loop contributions already used by us in the NNLO QCD calculation of the LHC process pp → γγγ [Chawdhry et al. (2019)]. Our results agree with a recent calculation of the same amplitude [Abreu et al. (2020)] which was performed using different techniques. We combine several modern computational techniques, notably, analytic solutions for the IBP identities, finite-field reconstruction techniques as well as the recent approach [Chen (2019)] for efficiently projecting helicity amplitudes. Our framework appears well-suited for the calculation of two-loop multileg amplitudes for which complete sets of master integrals exist.
A convexity enforcing $${C}^{{0}}$$ interior penalty method for the Monge–Ampère equation on convex polygonal domains
Authors: Brenner Susanne C. , Sung Li-yeng , Tan Zhiyu , Zhang Hongchao
Published: June 2021

We design and analyze a $$C^0$$

C
0

interior penalty method for the approximation of classical solutions of the Dirichlet boundary value problem of the Monge–Ampère equation on convex polygonal domains. The method is based on an enhanced cubic Lagrange finite element that enables the enforcement of the convexity of the approximate solutions. Numerical results that corroborate the a priori and a posteriori error estimates are presented. It is also observed from numerical experiments that this method can capture certain weak solutions.
Role of Indocyanine Green to Mitigate Wound Complications in Component Separation Technique for Ventral Hernia Repair—Our Early Experience
Authors: Gandhi Jignesh , Banker Amay , Chaudhari Sadashiv , Shinde Pravin
Published: June 2021

Background

The ease of the anterior component separation technique (ACST) makes it an attractive surgical option for ventral hernia repairs (VHR). Incorporation of indocyanine green‐fluorescence angiography (ICG‐FA) to map soft tissue perfusion during open ACST is an effective way to minimize the wound complications. This study aims to evaluate the impact of adoption of ICG‐FA on wound‐related complications following open ACST in VHR.

Methods

We performed a retrospective review of patients who underwent VHR with the open ACST at a single centre between March 2018 and July 2020. The study comprised of consecutive cases of open ACST with onlay meshplasty done before (March 2018–April 2019) and after (May 2019 to July 2020) implementation of ICG‐FA for intra‐operative perfusion mapping of subcutaneous tissue and skin.

Results

The pre‐ICG group and post‐ICG group were similar in terms of baseline patient demographics and peri‐operative details. The rate of surgical site occurrence's was higher in the pre‐ICG group, but this result was not statistically significant (46% vs. 26%; p value 0.189). Skin necrosis, however, was observed in significantly less patients of the post‐ICG cohort (29% vs. 5%; p value 0.045).

Conclusion

This study demonstrates the effectiveness of perfusion mapping by the use of ICG angiography to determine potential areas of decreased perfusion and thereby minimize wound complications. Using ICG‐FA to guide removal of at‐risk tissue to minimize wound complications may substantially improve the patients outcome.