bluuebunny/crossref_metadata_2025 huggingface dataset:
Prolonged Local In Vivo Delivery of Stimuli‐Responsive Nanogels That Rapidly Release Doxorubicin in Triple‐Negative Breast Cancer Cells
Authors: Zhang Yi , Dosta Pere , Conde João , Oliva Nuria , Wang Mian , Artzi Natalie
Published: January 2020

Triple negative breast cancer patients remain with chemotherapy as their only viable therapeutic option. However, the toxicity of available anticancer drugs and their inefficient delivery have limited the development of effective chemotherapy administration protocols and combination therapies. Drug delivery devices that can properly target chemotherapy to the right cells with efficient cancer‐cell killing may play a vital role in eliminating triple‐negative breast cancer. While systemic delivery results in low drug accumulation at the tumor site and for a short period of time, local delivery enables sustained drug release. However, a system that is able to provide rapid, yet prolonged action, would enable efficient tumor elimination. Herein, the development of dual‐sensitive nanogels is described that are designed to rapidly dislodge the chemotherapy drug, doxorubicin, inside cancer cells through dual‐sensitive action—pH and redox sensitivities—enabling efficient cancer‐cell killing while eliminating systemic side effects. Their embedding within a hydrogel injected next to a tumor in a triple‐negative breast‐cancer mouse model enables prolonged release of the drug with instantaneous action when inside the cells resulting in efficacious tumor elimination compared to sustained local delivery only. This technology can be used for the delivery of combination therapies and for the treatment of other solid tumors.
Relaxation of Extracellular Matrix Forces Directs Crypt Formation and Architecture in Intestinal Organoids
Authors: Hushka Ella A. , Yavitt F. Max , Brown Tobin E. , Dempsey Peter J. , Anseth Kristi S.
Published: January 2020

Intestinal organoid protocols rely on the use of extracellular scaffolds, typically Matrigel, and upon switching from growth to differentiation promoting media, a symmetry breaking event takes place. During this stage, the first bud like structures analogous to crypts protrude from the central body and differentiation ensues. While organoids provide unparalleled architectural and functional complexity, this sophistication is also responsible for the high variability and lack of reproducibility of uniform crypt‐villus structures. If function follows form in organoids, such structural variability carries potential limitations for translational applications (e.g., drug screening). Consequently, there is interest in developing synthetic biomaterials to direct organoid growth and differentiation. It has been hypothesized that synthetic scaffold softening is necessary for crypt development, and these mechanical requirements raise the question, what compressive forces and subsequent relaxation are necessary for organoid maturation? To that end, allyl sulfide hydrogels are employed as a synthetic extracellular matrix mimic, but with photocleavable bonds that temporally regulate the material's bulk modulus. By varying the extent of matrix softening, it is demonstrated that crypt formation, size, and number per colony are functions of matrix softening. An understanding of the mechanical dependence of crypt architecture is necessary to instruct homogenous, reproducible organoids for clinical applications.
A Biocompatible and Near‐Infrared Liposome for In Vivo Ultrasound‐Switchable Fluorescence Imaging
Authors: Liu Yang , Yao Tingfeng , Cai Wenbin , Yu Shuai , Hong Yi , Nguyen Kytai T. , Yuan Baohong
Published: January 2020

Fluorescence imaging is a remarkable tool for molecular targeting and multicolor imaging, but it suffers from low resolution in centimeter‐deep tissues. The recently developed ultrasound‐switchable fluorescence (USF) imaging has overcome this challenge and achieved in vivo imaging in a mouse with help from the indocyanine green (ICG) dye encapsulated poly(N‐isopropylacrylamide) (ICG‐PNIPAM) contrast agent. However, the ICG‐PNIPAM has shortcomings, such as concerns about cytotoxicity and blueshifted excitation and emission spectra. This study introduces a newly developed ICG‐encapsulated liposome to broaden the contrast agent selection for USF imaging and resolve the issues mentioned above. The emission peak of the ICG‐liposome is 836 nm with excellent biostability and USF imaging capability. Furthermore, the cell viability test verifies the low cytotoxicity feature. Eventually, both ex vivo and in vivo USF imaging are successfully achieved and 3D USF images are acquired. The ex vivo result confirms that the ICG‐liposome maintains the thermoresponsive characteristic at the right lobe of the liver and is able to conduct the USF imaging. The further in vivo USF imaging demonstrates that although the whole liver emitted fluorescence, only the right lobe of the liver contains the working ICG‐liposome.
Direct Imprinting of Quasi‐3D Nanophotonic Structures into Colloidal Quantum‐Dot Devices
Authors: Tang Xin , Chen Menglu , Ackerman Matthew M. , Melnychuk Christopher , Guyot‐Sionnest Philippe
Published: January 2020

Three‐dimensional (3D) subwavelength nanostructures have emerged and triggered tremendous excitement because of their advantages over the two‐dimensional (2D) counterparts in fields of plasmonics, photonic crystals, and metamaterials. However, the fabrication and integration of 3D nanophotonic structures with colloidal quantum dots (CQDs) faces several technological obstacles, as conventional lithographic and etching techniques may affect the surface chemistry of colloidal nanomaterials. Here, the direct fabrication of functional quasi‐3D nanophotonic structures into CQD films is demonstrated by one‐step imprinting with well‐controlled precision in both vertical and lateral directions. To showcase the potential of this technique, diffraction gratings, bilayer wire‐grid polarizers, and resonant metal mesh long‐pass filters are imprinted on CQD films without degrading the optical and electrical properties of CQD. Furthermore, a dual‐diode CQD detector into an unprecedented mid‐wave infrared two‐channel polarization detector is functionalized by embedding an imprinted bilayer wire‐grid polarizer within the CQDs. The results show that this approach offers a feasible pathway to combine quasi‐3D nanostructures with colloidal materials‐based optoelectronics and access a new level of light manipulation.
Lithium‐Battery Anode Gains Additional Functionality for Neuromorphic Computing through Metal–Insulator Phase Separation
Authors: Gonzalez‐Rosillo Juan Carlos , Balaish Moran , Hood Zachary D. , Nadkarni Neel , Fraggedakis Dimitrios , Kim Kun Joong , Mullin Kaitlyn M. , Pfenninger Reto , Bazant Martin Z. , Rupp Jennifer L. M.
Published: January 2020

Specialized hardware for neural networks requires materials with tunable symmetry, retention, and speed at low power consumption. The study proposes lithium titanates, originally developed as Li‐ion battery anode materials, as promising candidates for memristive‐based neuromorphic computing hardware. By using ex‐ and in operando spectroscopy to monitor the lithium filling and emptying of structural positions during electrochemical measurements, the study also investigates the controlled formation of a metallic phase (Li7Ti5O12) percolating through an insulating medium (Li4Ti5O12) with no volume changes under voltage bias, thereby controlling the spatially averaged conductivity of the film device. A theoretical model to explain the observed hysteretic switching behavior based on electrochemical nonequilibrium thermodynamics is presented, in which the metal‐insulator transition results from electrically driven phase separation of Li4Ti5O12 and Li7Ti5O12. Ability of highly lithiated phase of Li7Ti5O12 for Deep Neural Network applications is reported, given the large retentions and symmetry, and opportunity for the low lithiated phase of Li4Ti5O12 toward Spiking Neural Network applications, due to the shorter retention and large resistance changes. The findings pave the way for lithium oxides to enable thin‐film memristive devices with adjustable symmetry and retention.
Diverse Interface Structures in TiO2 (B)/Anatase Dual‐Phase Nanofibers
Authors: Lei Yimin , Lin Xin , Wu Dekai , Wang Zhan , Zhong Peng , Ma Xiaohua , Sun Jie
Published: January 2020

The understanding on the interfaces between different polymorphs of nanosized TiO2 from the perspective of crystallography has great theoretical value for the interface and property design and regulation. In this work, TiO2 (B)/anatase dual‐phase nanofibers containing different interface structures are investigated in detail. The X‐ray diffraction (XRD) is first employed to illustrate the detailed phase evolution during the calcination under different temperatures. Four types of interfaces with different structures are further studied by transmission electron microscopy (TEM). Single crystal form induced different interfaces is confirmed, which is thought to be the universal conclusion in monoclinic crystal systems. Meanwhile, the other two interface structures in {100} single crystal form are also observed in the samples under higher temperature calcination. Invariant line strain calculation is carried out for the four interfaces. The calculated crystallographic features agree well with the observed results. Furthermore, taken [010]TB//[001]TA as the rotation axis, the orientation difference of the single crystal form induced interfaces is confirmed to be 72.5°, corresponding to the β angle of TiO2 (B). The orientation relationships of the other two interfaces in {100} single crystal form can also be achieved by 7.5° and −4.5° rotation from the interface with the same single crystal form.
Covalent Mucin Coatings Form Stable Anti‐Biofouling Layers on a Broad Range of Medical Polymer Materials
Authors: Winkeljann Benjamin , Bauer Maria G. , Marczynski Matthias , Rauh Theresa , Sieber Stephan A. , Lieleg Oliver
Published: January 2020

Approximately 10% of all hospital patients contract infections from temporary clinical implants such as urinal and vascular catheters or tracheal tubes. The ensuing complications reach from patient inconvenience and tissue inflammation to severe, life threatening complications such as pneumonia or bacteremia. All these device‐associated nosocomial infections have the same origin: biofouling, i.e., the unwanted deposition of proteins, bacteria, and cells onto the device. To date, most strategies to overcome these problems are device specific, which results in high development efforts and costs. Here, it is demonstrated how one and the same coupling mechanism can be used to create a covalent antifouling coating employing mucin glycoproteins on multiple materials: with this method, a stable mucin layer can be generated on a broad range of polymer materials which are frequently used in medical engineering. It is shown that the mucin coating exhibits excellent stability against mechanical, thermal, and chemical challenges and reduces protein adsorption as well as prokaryotic and eukaryotic cell adhesion. Thus, the coating mechanism described here introduces a promising strategy to overcome biofouling issues on a broad range of medical devices.
Lasing‐Encoded Microsensor Driven by Interfacial Cavity Resonance Energy Transfer
Authors: Yuan Zhiyi , Wang Ziyihui , Guan Peng , Wu Xiaoqin , Chen Yu‐Cheng
Published: January 2020

Microlasers are emerging tools for biomedical applications. In particular, whispering‐gallery‐mode (WGM) microlasers are promising candidates for sensing at the biointerface owing to their high quality‐factor and potential in molecular assays, and intracellular and extracellular detection. However, lasing particles with sensing functionality remain challenging since the overlap between the WGM optical mode and external gain medium is much lower compared to internal gain inside the cavity. To overcome this problem, the concept of Förster resonant energy transfer (FRET) is exploited on WGM droplet microlaser by separating donor and acceptor molecules at the cavity–surface interface. It is first discovered that the interfacial FRET laser not only originates from conventional FRET but utilizes coherent radiative energy transfer (CRET) to excite acceptor molecules by inducing light‐harvesting effect near the cavity interface. Simulations and experiments have revealed that the absorption spectrum of individual analyte plays a crucial role in interfacial FRET laser. Distinct lasing spectra can therefore distinguish molecules of different absorption properties upon binding. Finally, detection of small fluorescent molecules and photosynthetic protein is performed. The results presented here not only demonstrate the wide‐ranging potential of microlaser external cavity implementation in molecular sensing applications, but also provide comprehensive insights into cavity energy transfer in laser physics.
Hydrophobic Metal–Organic Frameworks: Assessment, Construction, and Diverse Applications
Authors: Xie Lin‐Hua , Xu Ming‐Ming , Liu Xiao‐Min , Zhao Min‐Jian , Li Jian‐Rong
Published: January 2020

Tens of thousands of metal–organic frameworks (MOFs) have been developed in the past two decades, and only ≈100 of them have been demonstrated as porous and hydrophobic. These hydrophobic MOFs feature not only a rich structural variety, highly crystalline frameworks, and uniform micropores, but also a low affinity toward water and superior hydrolytic stability, which make them promising adsorbents for diverse applications, including humid CO2 capture, alcohol/water separation, pollutant removal from air or water, substrate‐selective catalysis, energy storage, anticorrosion, and self‐cleaning. Herein, the recent research advancements in hydrophobic MOFs are presented. The existing techniques for qualitatively or quantitatively assessing the hydrophobicity of MOFs are first introduced. The reported experimental methods for the preparation of hydrophobic MOFs are then categorized. The concept that hydrophobic MOFs normally synthesized from predesigned organic ligands can also be prepared by the postsynthetic modification of the internal pore surface and/or external crystal surface of hydrophilic or less hydrophobic MOFs is highlighted. Finally, an overview of the recent studies on hydrophobic MOFs for various applications is provided and suggests the high versatility of this unique class of materials for practical use as either adsorbents or nanomaterials.
Sensitive Terahertz Detection and Imaging Driven by the Photothermoelectric Effect in Ultrashort‐Channel Black Phosphorus Devices
Authors: Guo Wanlong , Dong Zhuo , Xu Yijun , Liu Changlong , Wei Dacheng , Zhang Libo , Shi Xinyao , Guo Cheng , Xu Huang , Chen Gang , Wang Lin , Zhang Kai , Chen Xiaoshuang , Lu Wei
Published: January 2020

Terahertz (THz) photon detection is of particular appealing for myriad applications, but it still lags behind efficient manipulation with electronics and photonics due to the lack of a suitable principle satisfying both high sensitivity and fast response at room temperature. Here, a new strategy is proposed to overcome these limitations by exploring the photothermoelectric (PTE) effect in an ultrashort (down to 30 nm) channel with black phosphorus as a photoactive material. The preferential flow of hot carriers is enabled by the asymmetric Cr/Au and Ti/Au metallization with the titled‐angle evaporation technique. Most intriguingly, orders of magnitude field‐enhancement beyond the skin‐depth limit and photon absorption across a broadband frequency can be achieved. The PTE detector has excellent sensitivity of 297 V W−1, noise equivalent power less than 58 pW/Hz0.5, and response time below 0.8 ms, which is superior to other thermal‐based detectors at room temperature. A rigorous comparison with existing THz detectors, together with verification by further optical‐pumping and imaging experiments, substantiates the importance of the localized field effect in the skin‐depth limit. The results allow solid understanding on the role of PTE effect played in the THz photoresponse, opening up new opportunities for developing highly sensitive THz detectors for addressing targeted applications.
Bioresorbable Materials on the Rise: From Electronic Components and Physical Sensors to In Vivo Monitoring Systems
Authors: La Mattina Antonino A. , Mariani Stefano , Barillaro Giuseppe
Published: January 2020

Over the last decade, scientists have dreamed about the development of a bioresorbable technology that exploits a new class of electrical, optical, and sensing components able to operate in physiological conditions for a prescribed time and then disappear, being made of materials that fully dissolve in vivo with biologically benign byproducts upon external stimulation. The final goal is to engineer these components into transient implantable systems that directly interact with organs, tissues, and biofluids in real‐time, retrieve clinical parameters, and provide therapeutic actions tailored to the disease and patient clinical evolution, and then biodegrade without the need for device‐retrieving surgery that may cause tissue lesion or infection. Here, the major results achieved in bioresorbable technology are critically reviewed, with a bottom‐up approach that starts from a rational analysis of dissolution chemistry and kinetics, and biocompatibility of bioresorbable materials, then moves to in vivo performance and stability of electrical and optical bioresorbable components, and eventually focuses on the integration of such components into bioresorbable systems for clinically relevant applications. Finally, the technology readiness levels (TRLs) achieved for the different bioresorbable devices and systems are assessed, hence the open challenges are analyzed and future directions for advancing the technology are envisaged.
Superior Textured Film and Process Tolerance Enabled by Intermediate‐State Engineering for High‐Efficiency Perovskite Solar Cells
Authors: Wang Shubo , Chen Yiqi , Li Ruiyi , Xu Yibo , Feng Jiangshan , Yang Dong , Yuan Ningyi , Zhang Wen‐Hua , Liu Shengzhong (Frank) , Ding Jianning
Published: January 2020

As the power conversion efficiency (PCE) of perovskite solar cells (PSCs) is increased to as high over 25%, it becomes pre‐eminent to study a scalable process with wide processing window to fabricate large‐area uniform perovskite films with good light‐trapping performance. A stable and uniform intermediate‐state complex film is obtained by using tetramethylene sulfoxide (TMSO), which extends the annealing window to as long as 20 min, promotes the formation of a high‐quality perovskite film with larger grains (over 400 nm) and spontaneously forms the surface texture to result in an improved fill factor and open‐circuit voltage (Voc). Moreover, the superior surface texture significantly increases the long‐wavelength response, leading to an improved short‐circuit current density (Jsc). As a result, the maximum PCE of 21.14% is achieved based on a simple planar cell structure without any interface passivation. Moreover, a large area module with active area of 6.75 cm2 is assembled using the optimized TMSO process, showing efficiency as high as 16.57%. The study paves the way to the rational design of highly efficient PSCs for potential scaled‐up production.
Tailored Lipoprotein‐Like miRNA Delivery Nanostructure Suppresses Glioma Stemness and Drug Resistance through Receptor‐Stimulated Macropinocytosis
Authors: Jiang Gan , Chen Huan , Huang Jialin , Song Qingxiang , Chen Yaoxing , Gu Xiao , Jiang Zhenhuan , Huang Yukun , Lin Yingying , Feng Junfeng , Jiang Jiyao , Bao Yinghui , Zheng Gang , Chen Jun , Chen Hongzhuan , Gao Xiaoling
Published: January 2020

Glioma initiating cells (GICs) function as the seed for the propagation and relapse of glioma. Designing a smart and efficient strategy to target the GICs and to suppress the multiple signaling pathways associated with stemness and chemoresistance is essential to achieving a cancer cure. Inspired by the metabolic difference in endocytosis between GICs, differentiated glioma cells, and normal cells, a tailored lipoprotein‐like nanostructure is developed to amplify their internalization into GICs through receptor‐stimulated macropinocytosis. As CXCR4 is highly expressed on GICs and glioma tumor sites, meanwhile, the activation of CXCR4 induces the receptor‐stimulated macropinocytosis pathway in GICs, this CXCR4 receptor‐stimulated lipoprotein‐like nanoparticle (SLNP) achieves efficient accumulation in GICs in vitro and in vivo. By carrying microRNA‐34a in the core, this tailored SLNP reduces sex‐determining region Y‐box 2 and Notch1 expression, powerfully inhibits GICs stemness and chemoresistance, and significantly prolongs the survival of GICs‐bearing mice. Taken together, a tailored lipoprotein‐based nanostructure realizes efficient GICs accumulation and therapeutic effect through receptor‐stimulated macropinocytosis, providing a powerful nanoplatform for RNA interference drugs to combat glioma.
Human athletic paleobiology; using sport as a model to investigate human evolutionary adaptation
Authors: Longman Daniel P. , Wells Jonathan C. K. , Stock Jay T.
Published: January 2020

The use of sport as a conceptual framework offers unprecedented opportunities to improve our understanding of what the body does, shedding new light on our evolutionary trajectory, our capacity for adaptation, and the underlying biological mechanisms. This approach has gained traction over recent years. To date, sport has facilitated exploration not only of the evolutionary history of our species as a whole, but also of human variation and adaptation at the interindividual and intraindividual levels. At the species level, analysis of lower and upper limb biomechanics and energetics with respect to walking, running and throwing have led to significant advances in the understanding of human adaptations relative to other hominins. From an interindividual perspective, investigation of physical activity patterns and endurance running performance is affording greater understanding of evolved constraints of energy expenditure, thermoregulatory energetics, signaling theory, and morphological variation. Furthermore, ultra‐endurance challenges provoke functional trade‐offs, allowing new ground to be broken in the study of life history trade‐offs and human adaptability. Human athletic paleobiology—the recruitment of athletes as study participants and the use of contemporary sports as a model for studying evolutionary theory—has great potential. Here, we draw from examples in the literature to provide a review of how the use of athletes as a model system is enhancing understanding of human evolutionary adaptation.
Concerted variation of the 3′ regulatory region of Ig heavy chain and Gm haplotypes across human continental populations
Authors: Frezza Domenico , Martinez‐Labarga Cristina , Giambra Vincenzo , Serone Eliseo , Scano Giuseppina , Rickards Olga , D'Addabbo Pietro , Novelletto Andrea
Published: January 2020

Objectives

The 3′ regulatory region of the immunoglobulin heavy chain gene (IGH) includes the HS1.2 enhancer displaying length polymorphism with four known variants. The goal of the research was to provide an overview of this variability and of its evolutionary significance across human populations.

Materials and Methods

We compiled published and original data on HS1.2 polymorphism in 3,100 subjects from 26 human populations. Moreover, we imputed the haplotypic arrangement of the HS1.2 region in the 1000 Genomes Project (1KGP). In this dataset, imputation could also be obtained for the G1m‐G3m allotype by virtue of the precise correspondence between serological types and amino acid (and DNA) substitutions in IGHG1 and IGHG3.

Results

HS1.2 variant frequencies displayed similar patterns of continental partitioning as those reported in the literature for the physically neighboring IGHG1‐IGHG3 system. The 1KGP data revealed that linkage disequilibrium (LD) can explain the spread of joint HS1.2‐IGHG1‐IGHG3 associations across continents and within continental populations, with stronger LD out of Africa and the features of an evolutionarily stable genomic block with differential expression in lymphoblastoid cell lines.

Discussion

Strong population structuring involves at least the entire 70 kb genomic region here considered, due to the tight LD which maintained HS1.2, IGHG1, and IGHG3 in nonrandom arrangements. This might be key to better understand the evolutionary path of the entire genomic region driven by immune response capabilities, during the formation of continental gene pools.
Collective Tunnelling of Strongly Interacting Cold Atoms in a Double‐Well Potential
Authors: Sokolovski Dmitri , Gutiérrez de la Cal Xavier , Pons Marisa
Published: January 2020

It is known that under resonance conditions, a group of strongly interacting bosonic atoms, trapped in a double‐well potential, mimics a single particle, performing Rabi oscillations between the wells. By implication, all atoms need to tunnel at roughly the same time, even though the Bose–Hubbard Hamiltonian accounts only for one‐atom‐at‐a‐time transfers. The mechanism of this collective behavior is analyzed, the Rabi frequencies in the process are evaluated, and the limitation of this simple picture is discussed. In particular, it is shown that the small rapid oscillations superimposed on the slow Rabi cycle result from splitting the transferred cluster at the sudden onset of tunnelling, and disappear if tunnelling is turned on gradually.
The Gravitational Energy–Momentum Density of Radially Accelerated Observers in Schwarzschild Spacetime
Authors: Formiga J. B.
Published: January 2020

A hybrid machinery that is useful for calculations in teleparallel theories when the spacetime is spherically symmetric is developed. Using this machinery, the gravitational energy–momentum tensor density of the Schwarzschild spacetime is evaluated in a frame adapted to observers that accelerate in the radial direction. The energy density, the total energy, and the gravitational energy‐momentum flux are obtained. The regularization procedure and the limit where gravity is absent is discussed. It turns out that the regularized energy and energy–momentum flux are consistent in the whole spacetime. The continuity equation for the gravitational energy–momentum also holds for any point outside the black hole. Finally, the static and freely falling cases are discussed. It is found that a static observer measures a negative gravitational energy density, while a freely falling one measures a vanishing density.
Soft Lattice and Defect Covalency Rationalize Tolerance of β‐CsPbI3 Perovskite Solar Cells to Native Defects
Authors: Chu Weibin , Saidi Wissam A. , Zhao Jin , Prezhdo Oleg V.
Published: January 2020

Although all‐inorganic metal halide perovskites (MHPs) have shown tremendous improvement, they are still inferior to the hybrid organic–inorganic MHPs in efficiency. Recently, a conceptually new β‐CsPbI3 perovskite reached 18.4 % efficiency combined with good thermodynamic stability at ambient conditions. We use ab initio non‐adiabatic molecular dynamics to show that native point defects in β‐CsPbI3 are generally benign for nonradiative charge recombination, regardless of whether they introduce shallow or deep trap states. These results indicate that MHPs do not follow the simple models used to explain defect‐mediated charge recombination in the conventional semiconductors. The strong tolerance is due to the softness of the perovskite lattice, which permits separation of electrons and holes upon defect formation, and only allows carriers to couple to the low‐frequency vibrations. Both factors decrease notably the non‐adiabatic coupling and slow down the dissipation of energy to heat.
Photodriven Active Ion Transport Through a Janus Microporous Membrane
Authors: Yang Jinlei , Liu Pengchao , He Xiao , Hou Junjun , Feng Yaping , Huang Zhiwei , Yu Lian , Li Lianshan , Tang Zhiyong
Published: January 2020

Precise control of ion transport is a fundamental characteristic for the sustainability of life. It remains a great challenge to develop practical and high‐performance artificial ion‐transport system that can allow active transport of ions (protons) in an all solid‐state nanoporous material. Herein, we develop a Janus microporous membrane by combining reduced graphene oxide (rGO) and conjugated microporous polymer (CMP) for controllable photodriven ion transport. Upon light illumination, a net ionic current is generated from the CMP to the rGO side of the membrane, indicating that the rGO/CMP Janus membrane can realize photodriven directional and anti‐gradient ion transport. Analogously to the p‐n junction in photovoltaic devices, light is firstly converted into separated charges to trigger a transmembrane potential, which subsequently drives directional ion movement. For the first time, this method enables integration of a photovoltaic effect with an ionic field to drive active ion transport. With the advantages of scaled up production and easy fabrication, the concept of photovoltaic ion transport based on Janus microporous membrane may find wide application in energy storage and conversion, photodriven ion‐sieving, and water treatment.
Solidification of sulfur and arsenic in gold concentrate and leaching of the gold by thiosulfate
Authors: He Yi , Hu Xianzhi , Zi Futing , Yang Baomin , Cheng Huiling
Published: January 2020

The processing of refractory minerals rich in arsenic and sulfur often causes give off arsenic and sulfur contamination during roasting and oxidation pretreatments. In this paper, the solidification of elemental arsenic and sulfur by adding calcium‐containing compounds (calcium oxide, calcium carbonate, and calcium hydroxide) during roasting and oxidation was investigated with the aim of reducing environmental pollution. At the same time, the gold leaching from residues produced by solidification roasting and oxidation using nontoxic and environmentally friendly green copper‐ammonia‐thiosulfate method was also studied. The results indicated that a relatively better solidification effect of SO2 and As2O3 was achieved by adding Ca (OH)2, with a solidification efficiency for sulfur and arsenic as 84.67% and 50%, respectively. When copper‐ammonia‐thiosulfate leaching was carried out on the residues after solidification roasting, it was found that a 90% gold leaching percentage was obtained. Via characterization using Brunauer–Emmett–Teller surface area, scanning electron microscope, X‐ray diffraction, and X‐ray photoelectron spectroscopy, it was also found that the arsenic and sulfur in arsenopyrite were oxidized into stable and safe sulfates and arsenates after solidification. The results show that solidification roasting oxidation is an efficient and environmentally friendly pretreatment method, and the gold in the calcine can be effectively leached out via the green copper‐ammonia‐thiosulfate system.
Processing–structure–property relationship in direct laser writing carbonization of polyimide
Authors: Wang Rui , Duan Xiaoshuang , Yao Jingwen , Ruan Xiaojun , Yao Yanbo , Liu Tao
Published: January 2020

Direct laser writing carbonization (DLWc) of polyimide has recently emerged as a versatile method for facile fabrication of a variety of functional devices. Up‐to‐date, there is still a lack of comprehensive and in‐depth experimental studies to understand the processing‐structure–property relationship involved in this promising technique. With assistance of methylene blue adsorption as an in situ porous structure characterization method along with scanning electron microscopy, Raman scattering spectroscopy, X‐ray photoelectron spectroscopy, and electrical property measurements, we systematically investigate the multiscale structure evolution and the electrical sheet resistance of the carbon lines fabricated by DLWc at varied laser processing conditions. The key processing parameters being investigated included: laser power (P), laser beam scanning speed (S), distance of laser beam waist to the surface of polyimide film (D), and their combined effect—the averaged areal laser energy density—(E). Quantitative relationships are established between these processing parameters and the specific surface area, the porosity, the degree of perfection of the layered carbon or graphitic basic structure units, as well as the electrical sheet resistance of the carbon lines created by DLWc. The comprehensive and quantitative processing‐multiscale structure–electrical property relationships for DLWc established in this study expect to be useful for better understanding the complicated photo‐thermally induced polyimide pyrolysis/carbonization process.
A highly flexible, electrically conductive, and mechanically robust graphene/epoxy composite film for its self‐damage detection
Authors: Meng Qingshi , Kenelak Vincent , Chand Aron , Kang Hailan , Han Sensen , Liu Tianqing
Published: January 2020

Advanced functional composites have attracted a great attention for fabricating flexible devices. In this article, the GnP/epoxy composite film was prepared by mixing graphene platelets (GnPs) with epoxy through sonication process. The morphology, mechanical properties, and electrical conductivity of the prepared composites were investigated. As the GnP contents increased from 2.5 to 7.5 vol%, the composites showed an increase in strain sensitivity with the rapid decrease in the strain gauge to 4.4. Additionally, when dynamic movement of the flexible film was performed, at bending and twist angle of 135° and 180°, respectively, steady increase in both resistance changes were detected and compared. The electrical resistance of the flexible was measured over a temperature range of 20–95°C, an increase in temperature lead to a linearly equivalent increase in resistance. The composites can also detect slight pressure changes at 2 kPa compression force with rapid decrease of resistance. Additionally, fatigue test was performed with stable, sensitive, and no distinguishable reading under 2,000 stretching cycles. The composite film exhibits an excellent self‐sensing responds when fracture occurred. Thus, the obtained highly flexible, conductive, and mechanical robust composite sensor can be applied as advanced composites sensors for health monitoring.
Reversibly highly stretchable and self‐healable zwitterion‐containing polyelectrolyte hydrogel with high ionic conductivity for high‐performance flexible and cold‐resistant supercapacitor
Authors: Diao Wenjing , Wu Linlin , Ma Xiaofeng , Wang Lei , Bu Ximan , Ni Wei , Yang Xinfeng , Fang Ying
Published: January 2020

It remains challenging to develop stretchable and self‐healable polymer electrolytes with improved ion‐conductive nature for high‐performance multifunctional flexible supercapacitors. Herein, a P(AM‐SBMA‐AMPS)‐SiO2 zwitterion‐containing polyelectrolyte hydrogel is fabricated via copolymerization of acrylamide (AM), sulfobetaine methacrylate (SBMA) zwitterionic monomer, and 2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid (AMPS) anionic monomer grafted from the surface of vinyl silica nanoparticles (VSNPs). The hydrogen bonding among polymer chains and the high‐density dynamic ionic interactions between SBMA and AMPS work as reversible “sacrificial bonds” to toughen hydrogel, while the VSNPs function as multifunctional crosslinkers and stress transfer centers, which makes these hydrogels tough (fracture energy 2.7 MJ m−3), stretchable (fracture strain 4,016%), and self‐healable (fracture strain of healable sample 775%). More importantly, this zwitterion‐containing polyelectrolyte hydrogel exhibits high ionic conductivities (3.4 S m−1) owing to the highly hydration capacity of the zwitterionic polyelectrolyte copolymer which produced efficient ion migration channels for ion transport. Accordingly, a flexible supercapacitor based on this multifunctional hydrogel as electrolyte demonstrates a high electric double‐layer capacitive capacitance of 60.6 F g−1 at 0.5 A g−1 and excellent capacitance retention of ~98% over 1,000 cycles as well as encouraging electrochemical properties at subzero temperature. This work provides new insights into the synthesis of highly conductive and multifunctional polyelectrolyte hydrogels for high‐performance flexible supercapacitors. © 2020 Wiley Periodicals, Inc.
Cryptic Chemical Communication: Secondary Metabolic Responses Revealed by Microbial Co‐culture
Authors: Liu Chao , Kakeya Hideaki
Published: January 2020

Microbial secondary metabolites (SMs) have long been viewed as a significant source of novel pharmaceutical and agrochemical molecules. With the increasing availability of genomic data, numerous biosynthetic gene clusters (BGCs) have been discovered. Despite the presence of tens of thousands of BGCs that can theoretically produce extremely diverse SMs, many gene clusters remain in a silent state under axenic culture conditions. Co‐culture is a promising research approach as it stimulates the expression of cryptic BGCs to produce novel metabolites and also mimics natural interspecies interactions in a laboratory environment. In recent years, the roles of SMs in microbial communication have caught the attention of researchers and our understanding of microbes and their production of remarkable SMs has improved. SMs may be extensively involved in a variety of communication events among microorganisms. We herein summarize certain representative findings in the field of chemical communication involving SMs in co‐culture systems.
Bottom‐Up Fabrication of a Sandwich‐Like Carbon/Graphene Heterostructure with Built‐In FeNC Dopants as Non‐Noble Electrocatalyst for Oxygen Reduction Reaction
Authors: Lv Xiaoxia , Xue Xue , Gan Xingyu , Lv Chenhao , Sun Xiaochen , Wang Yun , Li Liangjun , Wang Hua
Published: January 2020

High‐performance non‐noble electrocatalysts for oxygen reduction reaction (ORR) are the prerequisite for large‐scale utilization of fuel cells. Herein, a type of sandwiched‐like non‐noble electrocatalyst with highly dispersed FeNx active sites embedded in a hierarchically porous carbon/graphene heterostructure was fabricated using a bottom‐up strategy. The in situ ion substitution of Fe3+ in a nitrogen‐containing MOF (ZIF‐8) allows the Fe‐heteroatoms to be uniformly distributed in the MOF precursor, and the assembly of Fe‐doped ZIF‐8 nano‐crystals with graphene‐oxide and in situ reduction of graphene‐oxide afford a sandwiched‐like Fe‐doped ZIF‐8/graphene heterostructure. This type of heterostructure enables simultaneous optimization of FeNx active sites, architecture and interface properties for obtaining an electron‐catalyst after a one‐step carbonization. The synergistic effect of these factors render the resulting catalysts with excellent ORR activities. The half‐wave potential of 0.88 V vs. RHE outperforms most of the none‐noble metal catalyst and is comparable with the commercial Pt/C (20 wt %) catalyst. Apart from the high activity, this catalyst exhibits excellent durability and good methanol‐tolerance. Detailed investigations demonstrate that a moderate content of Fe dopants can effectively increase the intrinsic activities, and the hybridization of graphene can enhance the reaction kinetics of ORR. The strategy proposed in this work gives an inspiration towards developing efficient noble‐metal‐free electrocatalysts for ORR.
Synopse der Naturgefahren für Köln
Authors: Schwarz Jochen , Maiwald Holger
Published: January 2020

Die Synopse der Naturgefahren für die Stadt Köln hat sich als Musterbeispiel für die Betrachtung multipler Naturgefahren erwiesen. In verschiedenen Forschungsprojekten wird auf die im Rahmen des Deutschen Forschungsnetzes Naturkatastrophen (DFNK) vorgelegten Ergebnisse zurückgegriffen. Dabei werden zum Teil die gleichen Ansätze für die Bebauung, Einwirkung bzw. Korrelation zur Ermittlung der Verluste zugrunde gelegt. Der Beitrag spiegelt aus aktueller Sicht, welche Fortschritte im Bereich der Multi‐Hazard‐ und Risikobewertung erreicht wurden, wie sich diese in den Prognosen und Szenarien niederschlagen und nicht zuletzt, welcher Forschungsbedarf weiterhin abzuleiten ist. Im Vordergrund steht die Fragestellung, welche Konsequenzen sich aus der Detailaufnahme der betroffenen Gebiete und Bestandsbebauung ergeben. In diesem Zusammenhang kommen die von den Autoren entwickelten Verletzbarkeits‐ bzw. Schadensfunktionen zur Anwendung, die für die betrachteten Naturgefahren (Erdbeben, Sturm, Hochwasser) eine Prognose der zu erwartenden Verteilung der Schadensgrade und die Neubestimmung der Verluste ermöglichen. In Abhängigkeit von der Wiederkehrperiode und unter Berücksichtigung der aktuellen Werteentwicklung lassen sich infolge der mikroskaligen Gebäudebetrachtung qualitative und quantitative Veränderungen begründen.
Towards Germanium Layered Materials as Superior Negative Electrodes for Li‐, Na‐, and K‐Ion Batteries
Authors: Loaiza Laura C. , Monconduit Laure , Seznec Vincent
Published: January 2020

The germanium high theoretical capacity renders it as a promising anode material with 1384 mAh/g for Li (Li15Ge4) and 369 mAh/g for Na (NaGe) and K (KGe). Nevertheless, Ge suffers from volume variations due to alkali insertion, to mitigate this issue several strategies have been proposed. Among them the use of layered Ge‐based phases, obtained from the CaGe2 Zintl phase by topotactic deintercalation of Ca2+ to form the germanane (GeH)n. This last one has a particular morphology of Ge6 rings interconnected to form planes that buffers the volume changes and shortens the diffusion pathways. Here, we have studied the germanane alkali storage properties and 2150, 495 and 205 mAh/g of reversible capacity were obtained for Li, Na and K, respectively. These results indicate that germanane can store more alkali ions than the predicted phases, perform well at high rates and maintain a good capacity retention.
The effect of treatment delay on time‐to‐recovery in the presence of unobserved heterogeneity
Authors: van Geloven Nan , Balan Theodor A. , Putter Hein , le Cessie Saskia
Published: January 2020

We study the effect of delaying treatment in the presence of (unobserved) heterogeneity. In a homogeneous population and assuming a proportional treatment effect, a treatment delay period will result in notably lower cumulative recovery percentages. We show in theoretical scenarios using frailty models that if the population is heterogeneous, the effect of a delay period is much smaller. This can be explained by the selection process that is induced by the frailty. Patient groups that start treatment later have already undergone more selection. The marginal hazard ratio for the treatment will act differently in such a more homogeneous patient group. We further discuss modeling approaches for estimating the effect of treatment delay in the presence of heterogeneity, and compare their performance in a simulation study. The conventional Cox model that fails to account for heterogeneity overestimates the effect of treatment delay. Including interaction terms between treatment and starting time of treatment or between treatment and follow up time gave no improvement. Estimating a frailty term can improve the estimation, but is sensitive to misspecification of the frailty distribution. Therefore, multiple frailty distributions should be used and the results should be compared using the Akaike Information Criterion. Non‐parametric estimation of the cumulative recovery percentages can be considered if the dataset contains sufficient long term follow up for each of the delay strategies. The methods are demonstrated on a motivating application evaluating the effect of delaying the start of treatment with assisted reproductive techniques on time‐to‐pregnancy in couples with unexplained subfertility.
Microbial growth rates and local external mass transfer coefficients in a porous bed biofilm system measured by 19F magnetic resonance imaging of structure, oxygen concentration, and flow velocity
Authors: Simkins Jeffrey W. , Stewart Philip S. , Codd Sarah L. , Seymour Joseph D.
Published: January 2020

19F nuclear magnetic resonance (NMR) oximetry and 1H NMR velocimetry were used to noninvasively map oxygen concentrations and hydrodynamics in space and time in a model packed bed biofilm system in the presence and absence of flow. The development of a local oxygen sink associated with a single gel bead inoculated with respiring Escherichia coli was analyzed with a phenomenological model to determine the specific growth rate of the bacteria in situ, returning a value (0.66 hr−1) that was close to that measured independently in planktonic culture (0.62 hr−1). The decay of oxygen concentration in and around the microbiologically active bead was delayed and slower in experiments conducted under continuous flow in comparison to no‐flow experiments. Concentration boundary layer thicknesses were determined and Sherwood numbers calculated to quantify external mass transfer resistance. Boundary layers were thicker in no‐flow experiments compared to experiments with flow. Whereas the oxygen concentration profile across a reactive biofilm particle was symmetric in no‐flow experiments, it was asymmetric with respect to flow direction in flow experiments with Sherwood numbers on the leading edge (Sh = 7) being larger than the trailing edge (Sh = 3.5). The magnitude of the experimental Sh was comparable to values predicted by a variety of correlations. These spatially resolved measurements of oxygen distribution in a geometrically complex model reveal in innovative detail the local coupling between microbial growth, oxygen consumption, and external mass transfer.
Apoptosis detection via automated algorithms to analyze biomarker translocation in reporter cells
Authors: Ahmed A. H. Rezwanuddin , Dereli‐Korkut Zeynep , Lee Joanne Haeun , Piracha Sidra , Gilchrist M. Lane , Jiang Xuejun , Wang Sihong
Published: January 2020

Rapid, efficient, and robust quantitative analyses of dynamic apoptotic events are essential in a high‐throughput screening workflow. Currently used methods have several bottlenecks, specifically, limitations in available fluorophores for downstream assays and misinterpretation of statistical image data analysis. In this study, we developed cytochrome‐C (Cyt‐C) and caspase‐3/‐8 reporter cell lines using lung (PC9) and breast (T47D) cancer cells, and characterized them from the response to apoptotic stimuli. In these two reporter cell lines, the spatial fluorescent signal translocation patterns served as reporters of activations of apoptotic events, such as Cyt‐C release and caspase‐3/‐8 activation. We also developed a vision‐based, tunable, automated algorithm in MATLAB to implement the robust and accurate analysis of signal translocation in single or multiple cells. Construction of the reporter cell lines allows live monitoring of apoptotic events without the need for any other dyes or fixatives. Our algorithmic implementation forgoes the use of simple image statistics for more robust analytics. Our optimized algorithm can achieve a precision greater than 90% and a sensitivity higher than 85%. Combining our automated algorithm with reporter cells bearing a single‐color dye/fluorophore, we expect our approach to become an integral component in the high‐throughput drug screening workflow.
An analysis of environmental sustainability in small & medium‐sized enterprises: Patterns and trends
Authors: Bakos Joseph , Siu Michele , Orengo Adalberto , Kasiri Narges
Published: January 2020

One of the greatest challenges facing the world today is climate change. The need to consistently advance with environmentally sustainable practices in today's businesses is crucial, and businesses are demanded to be more environmentally sustainable every day. This study conducts an analysis of the literature on small and medium‐sized enterprises' (SMEs) environmental sustainability by carefully examining 122 studies from 58 journals published from 2013 to 2019. We investigate the trends in drivers and barriers of sustainability adoption to inform both SMEs managers and policymakers. Our results also classify the reviewed studies on the basis of their methodologies and show the distribution of studies across industry sectors and locations in order to set directions for future research on sustainability practices of SMEs.