bluuebunny/crossref_metadata_2025 huggingface dataset:
Spectral CT quantification stability and accuracy for pediatric patients: A phantom study
Authors: Shapira Nadav , Mei Kai , Noël Peter B.
Published: January 2021

Background

Spectral computed tomography (spectral CT) provides access to clinically relevant measures of endogenous and exogenous materials in patients. For pediatric patients, current spectral CT applications include lesion characterization, quantitative vascular imaging, assessments of tumor response to treatment, and more.

Objective

The aim of this study is a comprehensive investigation of the accuracy and stability of spectral quantifications from a spectral detector‐based CT system with respect to different patient sizes and radiation dose levels relevant for the pediatric population.

Materials and methods

A spectral CT phantom with tissue‐mimicking materials and iodine concentrations relevant for pediatric imaging was scanned on a spectral detector CT system using a standard pediatric abdominal protocol at 100%, 67%, 33% and 10% of the nominal radiation dose level. Different pediatric patient sizes were simulated using supplemental 3D‐printed extension rings. Virtual mono‐energetic, iodine density, effective atomic number, and electron density results were analyzed for stability with respect to radiation dose and patient size.

Results

Compared to conventional CT imaging, a pronounced improvement in the stability of attenuation measurements across patient size was observed when using virtual mono‐energetic images. Iodine densities were within 0.1 mg/ml, effective atomic numbers were within 0.26 atomic numbers and electron density quantifications were within ±1.0% of their respective nominal values. Relative to the nominal dose clinical protocol, differences in attenuation of all tissue‐mimicking materials were maintained below 1.6 HU for a 33% dose reduction, below 2.7 HU for a 67% dose reduction and below 3.7 HU for a 90% dose reduction, for all virtual mono‐energetic energies equal to or greater than 50 keV. Iodine, and effective atomic number quantifications were stable to within 0.1 mg/ml and 0.06 atomic numbers, respectively, across all measured dose levels.

Conclusion

Spectral CT provides accurate and stable material quantification with respect to radiation dose reduction (up to 90%) and differing pediatric patient size. The observed consistency is an important step towards quantitative pediatric imaging at low radiation exposure levels.
Decreased serum creatinine levels predict short survival in amyotrophic lateral sclerosis
Authors: Guo Qi‐Fu , Hu Wei , Xu Liu‐Qing , Luo Hao , Wang Ning , Zhang Qi‐Jie
Published: January 2021

Objective

To explore the associations between serum creatinine and creatine kinase (CK) levels with survival in male and female ALS patients.

Methods

A prospective cohort study was carried out including 346 ALS patients with repeated serum creatinine and CK measurements. Kaplan Meier analysis and multivariable Cox regression were used to perform survival analysis.

Results

There were 218 male and 128 female patients, and the males had significantly higher baseline serum creatinine and CK levels than females. After multivariable Cox regression analysis, lower baseline serum creatinine levels were associated with a short survival in both male (≤61 μmol/L, HR: 1.629; 95%CI: 1.168–2.273) and female ALS patients (≤52 μmol/L, HR: 1.677; 95%CI: 1.042–2.699), whereas, the serum CK levels were not correlated with survival. Besides, creatinine levels were positively associated with ALSFRS‐R scores, and inversely with the decline rate of ALSFRS‐R per month. During follow‐up, serum creatinine levels tended to be decreased along with the disease progression, and the higher decline rate of creatinine per month (>1.5) showed significantly shorter survival, compared to the lower group (≤1.5) (30.0 months vs. 65.0 months, Chi square = 28.25, P < 0.0001).

Interpretation

Serum creatinine could be a reliable and easily accessible prognostic chemical marker for ALS, and decreased baseline creatinine levels could predict a poor prognosis and a short survival in both male and female ALS patients.
Noise covariance matrix estimation with subspace model identification for Kalman filtering
Authors: Mussot Vincent , Mercère Guillaume , Dairay Thibault , Arvis Vincent , Vayssettes Jérémy
Published: January 2021

A problem frequently encountered in Kalman filtering is the tuning of the noise covariance matrices. Indeed, misspecifying their values can drastically reduce the performance of the Kalman filter. Unfortunately, in most practical cases, noise statistics are not known a priori. This paper focuses on a method relying on subspace model identification theory to determine them accurately. This solution is developed for linear time invariant systems with stationary random disturbances having constant covariance matrices. Practically, these noise covariance matrices are determined from the comparison between an estimated state space representation and the discrete time state space representation involved in the Kalman filter equations. The method developed in this paper departs from most of the solutions available in the literature by the fact that it does not need any tuning parameter to be chosen by the user. After discussing theoretical results, several numerical examples are given to demonstrate the efficiency of the approach.
dynoNet: A neural network architecture for learning dynamical systems
Authors: Forgione Marco , Piga Dario
Published: January 2021

This article introduces a network architecture, called dynoNet, utilizing linear dynamical operators as elementary building blocks. Owing to the dynamical nature of these blocks, dynoNet networks are tailored for sequence modeling and system identification purposes. The back‐propagation behavior of the linear dynamical operator with respect to both its parameters and its input sequence is defined. This enables end‐to‐end training of structured networks containing linear dynamical operators and other differentiable units, exploiting existing deep learning software. Examples show the effectiveness of the proposed approach on well‐known system identification benchmarks.
Long‐term study alters assumptions about what drives excessive drinking
Authors: Enos Gary
Published: January 2021

Data from participants in the multiyear Chicago Social Drinking Project is helping the research community challenge long‐held notions about the factors that make drinkers more susceptible to an alcohol use disorder (AUD), as well as what occurs after individuals' drinking has escalated to problematic levels.
Advances in Targeted Therapy and Immunotherapy for Pancreatic Cancer
Authors: Liu Xiaoxiao , Li Zhang , Wang Yuexiang
Published: January 2021

Pancreatic cancer is a highly aggressive malignancy with an overall 5‐year survival rate of <6% due to therapeutic resistance and late‐stage diagnosis. These statistics have not changed despite 50 years of research and therapeutic development. Pancreatic cancer is predicted to become the second leading cause of cancer mortality by the year 2030. Currently, the treatment options for pancreatic cancer are limited. This disease is usually diagnosed at a late stage, which prevents curative surgical resection. Chemotherapy is the most frequently used approach for pancreatic cancer treatment and has limited effects. In many other cancer types, targeted therapy and immunotherapy have made great progress and have been shown to be very promising prospects; these treatments also provide hope for pancreatic cancer. The need for research on targeted therapy and immunotherapy is pressing due to the poor prognosis of pancreatic cancer, and in recent years, there have been some breakthroughs for targeted therapy and immunotherapy in pancreatic cancer. This review summarizes the current preclinical and clinical studies of targeted therapy and immunotherapy for pancreatic cancer and ends by describing the challenges and outlook.
Covalent Cell‐Loading Injectable Hydrogel Scaffold Significantly Promotes Tissue Regeneration In Vivo Compared with a Conventional Physical Cell‐Loading Hydrogel Scaffold
Authors: Kimura Yuka , Aoyama Seika , Ueda Natsumi , Katayama Tokitaka , Ono Kimika , Nagahama Koji
Published: January 2021

Currently, one of the major tendencies to be adopted for the design of hydrogel scaffolds in tissue engineering include that cells are loaded physically into the pores of 3D hydrogel networks. In this study, a drastic deviation from this tendency is proposed and developed a new type of hydrogel scaffold in which cells are covalently connected to 3D hydrogel networks via bioorthogonal click cross‐linking reactions of azide‐modified cells with alkyne‐modified polymers. The purpose of this study is to directly compare the utility of the covalent cell‐loading approach and the conventional physical cell‐loading approach as hydrogel scaffolds for in vivo tissue engineering. It is found that the proposed covalent cell‐loading approach significantly promotes tissue regeneration and functional recovery in vivo in comparison with the conventional physical cell‐loading approach. This is the first report demonstrating the importance of the covalent cell‐loading approach in tissue engineering. This covalent cell‐loading approach is applicable to a broad spectrum of mammalian cells, including stem cells. The present findings provide a promising new route to generate innovative hydrogel scaffolds for in vivo tissue engineering.
Sessile Liquid Marbles with Embedded Hydrogels as Bioreactors for Three‐Dimensional Cell Culture
Authors: Vadivelu Raja , Kashaninejad Navid , Nikmaneshi Mohammad Reza , Khadim Rubina Rahaman , Salehi Seyedeh Sarah , Ramulu Naveen Chintala , Sakai Yasuyuki , Nishikawa Masaki , Firoozabadi Bahar , Nguyen Nam‐Trung
Published: January 2021

Digital microfluidics based on liquid marble (LM) has recently emerged as a promising platform for liquid handling and cell‐based assays. However, evaporation is a critical problem in such platforms, hindering their wide‐range applications in various fields. This study aims to develop a functional sessile LM system for long‐term 3D cell culture. Previously, this study group and others demonstrated that floating LM‐based bioreactors could reduce the evaporation rate, and were thus suitable for growing multicellular spheroids. However, floating LMs are not robust and easily collapse. Herein, an evaporation‐reducing sessile LM by embedding LM with agarose gel is proposed. Through a series of comprehensive mathematical modeling, numerical simulations, and experimental investigations (both with and without biological cells), it is shown that such a platform acts as a moisture absorption system to control the evaporation and thus extends the life span of LMs. It is also found that unlike pure LMs, the LMs filled with agarose maintain their spherical shapes within 72 h inside a humidified incubator. Moreover, the presence of agarose significantly contributes to minimizing evaporation and improves the viability of the harvested multicellular spheroids. These results can open up a new avenue in using LMs in life sciences and chemistry.
Progresses in Tensile, Torsional, and Multifunctional Soft Actuators
Authors: Zou Min , Li Sitong , Hu Xiaoyu , Leng Xueqi , Wang Run , Zhou Xiang , Liu Zunfeng
Published: January 2021

Soft actuators have received intensive attention in the fields of soft robots, sensors, intelligent control, artificial intelligence, and visual intelligence. By combination of tensile and torsional deformations, different types of motions can be realized, such as bending, rolling, and jumping. Soft robotics need soft actuators, such as artificial muscles to lift or move objects to perform some work. Additionally, actuation integrated with functions of sensing, signal transmission, and control is also needed in the development of advanced intelligent systems, which further stimulates the requirement of multifunctional actuators. Here different types of soft actuators that can perform tensile and torsional actuations are summarized, including twisted fiber artificial muscles, shape memory polymers, hydrogels, liquid crystal polymers, electrochemical actuators with conducting polymers, and some natural materials. Examples are also included regarding the bending or rolling deformations of the actuators for lifting objects. Then, recent interesting reports about multifunctional soft actuators combined with sensing and signal transmission performances, are summarized. Last, a summary of different ways to realize tensile and torsional actuations, different materials, and designs for lifting or moving objects, as well as construction of multifunctional actuators with actuation and sensing functions is provided.
Copper Sulfide Nanoparticle‐Redirected Macrophages for Adoptive Transfer Therapy of Melanoma
Authors: Xu Jiaojiao , Zheng Binbin , Zhang Sihang , Liao Xueling , Tong Qinli , Wei Guoguang , Yu Sheng , Chen Gaoxian , Wu Aihua , Gao Shuai , Qian Yuyi , Xiao Zeyu , Lu Wei
Published: January 2021

Adoptive cell therapy (ACT) has achieved landmark advances in treating cancer in clinic. Recent advances in ACT of macrophages engineered to express chimeric antigen receptors (CARs) have shown effectiveness in treating solid tumors. However, the CAR‐macrophage therapy is dependent on tumor antigen recognition and gene editing methods. Herein, an adoptive macrophage therapy is presented through copper sulfide nanoparticle‐regulation that exhibits substantial antitumor effect in melanoma‐bearing mice, without the need for tumor antigen repertoire. Bone marrow derived macrophages (BMDMs) incubated with the nanoparticles promote the cellular production of reactive oxygen species (ROS) through dynamin‐related protein 1 (Drp1)‐mediated mitochodrial fission. The high intracellular ROS level directs BMDMs polarization toward M1 phenotype by classical IKK‐dependent NF‐κB activation. Moreover, the copper sulfide nanoparticle‐stimulated BMDMs (CuS‐MΦ) reduce the expression of programmed death‐1 (PD‐1) and exhibit enhanced phagocytic and digestive ability. Intratumoral transfer of CuS‐MΦ significantly prolongs the median survival time of the tumor‐bearing mice, remodels the tumor microenvironment, and elicits systemic antitumor immunity. These results suggest a cancer therapeutic approach of adoptively transferred macrophages through the induction of intracellular ROS with nanomaterials.
Laser‐Based Printing: From Liquids to Microstructures
Authors: Armon Nina , Greenberg Ehud , Edri Eitan , Nagler‐Avramovitz Ornit , Elias Yuval , Shpaisman Hagay
Published: January 2021

Assembly of materials into microstructures under laser guidance is attracting wide attention. The ability to pattern various materials and form 2D and 3D structures with micron/sub‐micron resolution and less energy and material waste compared with standard top‐down methods make laser‐based printing promising for many applications, for example medical devices, sensors, and microelectronics. Assembly from liquids provides a smaller feature size than powders and has advantages over other states of matter in terms of relatively simple setup, easy handling, and recycling. However, the simplicity of the setup conceals a variety of underlying mechanisms, which cannot be identified simply according to the starting or resulting materials. This progress report surveys the various mechanisms according to the source of the material—preformed or locally synthesized. Within each category, methods are defined according to the driving force of material deposition. The advantages and limitations of each method are critically discussed, and the methods are compared, shedding light on future directions and developments required to advance this field.
Engineered Multifunctional Nano‐ and Biological Materials for Cancer Immunotherapy
Authors: Brouillard Anthony , Deshpande Nilesh , Kulkarni Ashish A.
Published: January 2021

Cancer immunotherapy is set to emerge as the future of cancer therapy. However, recent immunotherapy trials in different cancers have yielded sub‐optimal results, with durable responses seen in only a small fraction of patients. Engineered multifunctional nanomaterials and biological materials are versatile platforms that can elicit strong immune responses and improve anti‐cancer efficacy when applied to cancer immunotherapy. While there are traditional systems such as polymer‐ and lipid‐based nanoparticles, there is a wide variety of other materials with inherent and additive properties that can allow for more potent activation of the immune system. By synthesizing and applying multifunctional strategies, it allows for a more extensive and more effective repertoire of tools to use in the wide variety of situations that cancer presents itself. Here, several types of nanoscale and biological material strategies and platforms that provide their inherent benefits for targeting and activating multiple aspects of the immune system are discussed. Overall, this review aims to provide a comprehensive understanding of recent advances in the field of multifunctional cancer immunotherapy and trends that pave the way for more diverse and tactical regression of tumors through soliciting responses by either the adaptive or innate immune system, and even both simultaneously.
Chiral Spin Textures in Amorphous Iron–Germanium Thick Films
Authors: Streubel Robert , Bouma D. Simca , Bruni Frank , Chen Xiaoqian , Ercius Peter , Ciston Jim , N'Diaye Alpha T. , Roy Sujoy , Kevan Steve D. , Fischer Peter , Hellman Frances
Published: January 2021

Topological solitary fields, such as magnetic and polar skyrmions, are envisioned to revolutionize microelectronics. These configurations have been stabilized in solid‐state materials with a global inversion symmetry breaking, which translates in magnetic materials into a vector spin exchange known as the Dzyaloshinskii–Moriya interaction (DMI), as well as spin chirality selection and isotropic solitons. This work reports experimental evidence of 3D chiral spin textures, such as helical spins and skyrmions with different chirality and topological charge, stabilized in amorphous Fe–Ge thick films. These results demonstrate that structurally and chemically disordered materials with a random DMI can resemble inversion symmetry broken systems with similar magnetic properties, moments, and states. Disordered systems are distinguished from systems with global inversion symmetry breaking by their degenerate spin chirality that allows for forming isotropic and anisotropic topological spin textures at remanence, while offering greater flexibility in materials synthesis, voltage, and strain manipulation.
Phenylene‐Bridged Bispyridinium with High Capacity and Stability for Aqueous Flow Batteries
Authors: Hu Shuzhi , Li Tianyu , Huang Mingbao , Huang Jinghua , Li Wenjin , Wang Liwen , Chen Zhenqiang , Fu Zhiyong , Li Xianfeng , Liang Zhenxing
Published: January 2021

A rotating phenyl ring is introduced between the two pyridinium rings, namely, 1,1′‐bis[3‐(trimethylamonium)propyl]‐4,4′‐(1,4‐phenylene)bispyridinium tetrachloride ((APBPy)Cl4), to form a switchable conjugation. In this design, the conjugation is switched “off” in the oxidized state and the two pyridinium rings behave independently during the redox process, yielding a concomitant transfer of two electrons at the same potential and, thus, simplifying the battery management. The conjugation is switched “on” in the reduced state and the charge can be effectively delocalized, lowering the Lewis basicity and improving its chemical stability. By pairing 0.50 m (APBPy)Cl4 with a 2,2,6,6‐tetramethylpiperidin‐1‐yl oxyl derivative as the positive electrolyte, a flow battery delivers a high standard cell voltage of 1.730 V and a high specific capacity of 20.0 Ah L–1. The battery also shows an exceptionally high energy efficiency of 80.8% and a superior cycling stability at 80 mA cm–2. This strategy proves itself a great success in engineering viologen as a two‐electron storage mediator with high capacity and stability.
Surface Plasmon‐Enhanced Short‐Wave Infrared Fluorescence for Detecting Sub‐Millimeter‐Sized Tumors
Authors: Huang Shengnan , Lin Ching‐Wei , Qi Jifa , Iyer Archana Mahadevan , He Yanpu , Li Yingzhong , Bardhan Neelkanth M. , Irvine Darrell J. , Hammond Paula T. , Belcher Angela M.
Published: January 2021

Short‐wave infrared (SWIR, 900–1700 nm) enables in vivo imaging with high spatiotemporal resolution and penetration depth due to the reduced tissue autofluorescence and decreased photon scattering at long wavelengths. Although small organic SWIR dye molecules have excellent biocompatibility, they have been rarely exploited as compared to their inorganic counterparts, mainly due to their low quantum yield. To increase their brightness, in this work, the SWIR dye molecules are placed in close proximity to gold nanorods (AuNRs) for surface plasmon‐enhanced emission. The fluorescence enhancement is optimized by controlling the dye‐to‐AuNR number ratio and up to ≈45‐fold enhancement factor is achieved. In addition, the results indicate that the highest dye‐to‐AuNR number ratio gives the highest emission intensity per weight and this is used for synthesizing SWIR imaging probes using layer‐by‐layer (LbL) technique with polymer coating protection. Then, the SWIR imaging probes are applied for in vivo imaging of ovarian cancer and the surface coating effect on intratumor distribution of the imaging probes is investigated in two orthotopic ovarian cancer models. Lastly, it is demonstrated that the plasmon‐enhanced SWIR imaging probe has great potential for fluorescence imaging‐guided surgery by showing its capability to detect sub‐millimeter‐sized tumors.
Two‐Photon Polymerization of Nanocomposites for the Fabrication of Transparent Fused Silica Glass Microstructures
Authors: Kotz Frederik , Quick Alexander S. , Risch Patrick , Martin Tanja , Hoose Tobias , Thiel Michael , Helmer Dorothea , Rapp Bastian E.
Published: January 2021

Fused silica glass is the material of choice for many high‐performance components in optics due to its high optical transparency combined with its high thermal, chemical, and mechanical stability. Especially, the generation of fused silica microstructures is of high interest for microoptical and biomedical applications. Direct laser writing (DLW) is a suitable technique for generating such devices, as it enables nearly arbitrary structuring down to the sub‐micrometer level. In this work, true 3D structuring of transparent fused silica glass using DLW with tens of micrometer resolution and a surface roughness of Ra ≈ 6 nm is demonstrated. The process uses a two‐photon curable silica nanocomposite resin that can be structured by DLW, with the printout being convertible to transparent fused silica glass via thermal debinding and sintering. This technology will enable a plethora of applications from next‐generation optics and photonics to microfluidic and biomedical applications with resolutions on the scale of tens of micrometers.
Hidden Vacancy Benefit in Monolayer 2D Semiconductors
Authors: Zhang Xiankun , Liao Qingliang , Kang Zhuo , Liu Baishan , Liu Xiaozhi , Ou Yang , Xiao Jiankun , Du Junli , Liu Yihe , Gao Li , Gu Lin , Hong Mengyu , Yu Huihui , Zhang Zheng , Duan Xiangfeng , Zhang Yue
Published: January 2021

Monolayer 2D semiconductors (e.g., MoS2) are of considerable interest for atomically thin transistors but generally limited by insufficient carrier mobility or driving current. Minimizing the lattice defects in 2D semiconductors represents a common strategy to improve their electronic properties, but has met with limited success to date. Herein, a hidden benefit of the atomic vacancies in monolayer 2D semiconductors to push their performance limit is reported. By purposely tailoring the sulfur vacancies (SVs) to an optimum density of 4.7% in monolayer MoS2, an unusual mobility enhancement is obtained and a record‐high carrier mobility (>115 cm2 V−1 s−1) is achieved, realizing monolayer MoS2 transistors with an exceptional current density (>0.60 mA µm−1) and a record‐high on/off ratio >1010, and enabling a logic inverter with an ultrahigh voltage gain >100. The systematic transport studies reveal that the counterintuitive vacancy‐enhanced transport originates from a nearest‐neighbor hopping conduction model, in which an optimum SV density is essential for maximizing the charge hopping probability. Lastly, the vacancy benefit into other monolayer 2D semiconductors is further generalized; thus, a general strategy for tailoring the charge transport properties of monolayer materials is defined.
Near‐Infrared Emission by Tuned Aggregation of a Porphyrin Compound in a Host–Guest Light‐Emitting Electrochemical Cell
Authors: Mone Mariza , Tang Shi , Genene Zewdneh , Murto Petri , Jevric Martyn , Zou Xianshao , Ràfols‐Ribé Joan , Abdulahi Birhan A. , Wang Jia , Mammo Wendimagegn , Andersson Mats R. , Edman Ludvig , Wang Ergang
Published: January 2021

The synthesis of 5,10,15,20‐tetrakis((5,10‐bis((2‐hexyldecyl)oxy)dithieno[3,2‐c:3′,2′‐h][1,5]naphthyridin‐2‐yl)ethynyl)porphyrin zinc(II) (Por4NT), a near‐infrared (NIR) emitting compound, comprising a zinc porphyrin core linked with triple bonds through its meso positions to four 5,10‐bis((2‐hexyldecyl)oxy)dithieno[3,2‐c:3′,2′‐h][1,5]naphthyridine (NT) arms is reported. Por4NT featured high solubility in common non‐polar solvents, which is ideal for easy processing through solution techniques, and high photoluminescence (PL) efficiency of ≈30% in dilute toluene solution. It also exhibited a strong tendency for aggregation because of its flat conformation, and this aggregation resulted in a strong redshifted emission and a drop in PL efficiency. A well‐matched PBDTSi‐BDD‐Py “host” terpolymer is therefore designed, which is capable of mitigating the aggregation of the Por4NT “guest”. An optimized blend of the host, guest, and an ionic‐liquid electrolyte is utilized as the active material in a light‐emitting electrochemical cell (LEC), which delivered strong NIR radiance of 134 µW cm‐2 with a long wavelength maximum at 810 nm at a low drive voltage of 5.0 V. The attainment of the strong NIR emission from the host–guest LEC is attributed to a tuned aggregation of the Por4NT emitter, which resulted in the desired aggregation‐induced redshift of the emission at a reasonably retained efficiency.
Electronic Structure and Optical Properties of Mixed Iodine/Bromine Lead Perovskites. To Mix or Not to Mix?
Authors: Diez‐Cabanes Valentin , Even Jacky , Beljonne David , Quarti Claudio
Published: January 2021

Halide mixing is a key strategy to tune the emission wavelength in lead halide perovskites but is also effective in improving the performance of halide perovskite solar cells. Yet, a clear and global picture of how halide alloying and related spatial in/homogeneous distribution influence the electronic and optical properties of halide perovskites is currently lacking. Considering the preeminent mixed iodine/bromine perovskite as a case study, state‐of‐the‐art hybrid density functional theory calculations are performed, exploring the full space of chemical composition and accounting for phase segregation effects. It is shown that, at low doping regime, halide impurities do not act as trap states and that a quasi‐linear opening of the bandgap occurs with increasing the bromine content. Phase segregation at the nanoscale, in turn, drastically affects the electronic structure of mixed halide systems, with namely bromine rich domains acting as barrier to hole diffusion. The energetic disorder probed by optical absorption in these mixed systems is surprisingly insensitive to configurational disorder, but mostly dominated by the coexistence of phases with various degrees of halide segregation.
Individual Si Nanospheres Wrapped in a Suspended Monolayer WS2 for Electromechanically Controlled Mie‐Type Nanopixels
Authors: Yan Jiahao , Liu Xinyue , Mao Bijun , Yang Guowei , Li Baojun
Published: January 2021

All‐dielectric (especially silicon) nanostructures that are capable of low‐loss sub‐wavelength light localization are favorable for miniaturized all‐optical or optoelectronic chips. Recently, Si waveguides have been integrated with the 2D transition‐metal dichalcogenides (TMDCs) with atomic thinness and intense light–matter interactions for high‐performance optoelectronic devices. However, further miniaturized and nanoscale optoelectronic devices are highly necessary and can be realized using all‐dielectric Si nanostructures. So far, realizing electrically controlled coupling between all‐dielectric nanostructures and TMDCs is challenging at the subwavelength scale. Here, the electrically controlled optical nanopixels using individual Si nanospheres are reported, which are conventional all‐dielectric units with strong Mie‐type magnetic resonances, wrapped in suspended WS2 monolayers. By applying gate voltages, deformation of the WS2 monolayer occurs as an opening or a closing umbrella. As a result, the scattering intensities are tuned by 40% because of the change in the Mie‐exciton coupling. Simultaneously, a doubled photoluminescence intensity enhancement with a 0.014 eV redshift of excitonic energy is observed, owing to the cooperation of the electromechanics and electrostatic doping. The findings suggest a new approach to build nanoscale optoelectronic devices and display units.
A Lipid Targeting, pH‐Responsive Nanoemulsion Encapsulating a DNA Intercalating Agent and HDAC Inhibitor Reduces TNBC Tumor Burden
Authors: Kim Bumjun , Hebert Jacob M. , Liu Daxing , Auguste Debra T.
Published: January 2021

Triple negative breast cancers (TNBCs) represent a heterogenous disease with high patient mortality relative to other breast cancers. Doxorubicin (Dox), a DNA intercalating drug, is widely used as chemotherapy for TNBC. However, it often accompanies severe side effects that limit the effective therapeutic dose. It is hypothesized that the combination of Dox with a histone deacetylase inhibitor, panobinostat (Pan), may improve therapeutic efficacy by attacking rapid cell proliferation and abnormal histone deacetylation. Herein, pH‐responsive, lipid targeting nanoemulsions (pLNEs) are designed to direct both Dox and Pan to TNBC cells that overexpress lysophosphatidic acid (LPA) receptor 1 (LPAR1) via the ratio of LPA to lysophosphatidylcholine and trigger Dox release via disassociation from docosahexanoic acid. Dox/Pan‐pLNEs result in higher intranuclear Dox compared to free Dox, free Dox/Pan, and Dox‐pLNEs. Tumors treated with Dox/Pan‐pLNEs exhibit 2.4‐fold reduction in tumor burden relative to free Dox alone. Molecular analysis reveals that MDA‐MB‐231 tumor growth inhibition is mediated by re‐expression of thioredoxin‐interacting protein and suppression of cytoplasmic p27kip1 and c‐Jun activation domain‐binding protein‐1. This lipid targeting, Dox/Pan encapsulating pLNE represents a platform for treating TNBC with greater therapeutic efficacy.
Quantum Nuclei at Weakly Bonded Interfaces: The Case of Cyclohexane on Rh(111)
Authors: Fidanyan Karen , Hamada Ikutaro , Rossi Mariana
Published: January 2021

The electronic properties of interfaces can depend on their isotopic constitution. One known case is that of cyclohexane physisorbed on Rh(111), in which isotope effects have been measured on the work function change and desorption energies. These effects can only be captured by calculations including nuclear quantum effects (NQE). In this paper, this interface is addressed employing dispersion‐inclusive density‐functional theory coupled to a quasi‐harmonic (QH) approximation for NQE, as well as to fully anharmonic ab initio path integral molecular dynamics (PIMD). The QH approximation is able to capture that deuterated cyclohexane has a smaller adsorption energy and lies about 0.01 Å farther from the Rh(111) surface than its isotopologue, which can be correlated to the isotope effect in the work function change. An investigation of the validity of the QH approximation relying on PIMD simulations, leads to the conclusion that although this interface is highly impacted by anharmonic quantum fluctuations in the molecular layer and at bonding sites, these anharmonic contributions play a minor role when analyzing isotope effects at low temperatures. Nevertheless, anharmonic quantum fluctuations cause an increase in the distance between the molecular layer and Rh(111), a consequent smaller overall work function change, and intricate changes in orbital hybridization.
A Micromachined Picocalorimeter Sensor for Liquid Samples with Application to Chemical Reactions and Biochemistry
Authors: Bae Jinhye , Zheng Juanjuan , Zhang Haitao , Foster Peter J. , Needleman Daniel J. , Vlassak Joost J.
Published: January 2021

Calorimetry has long been used to probe the physical state of a system by measuring the heat exchanged with the environment as a result of chemical reactions or phase transitions. Application of calorimetry to microscale biological samples, however, is hampered by insufficient sensitivity and the difficulty of handling liquid samples at this scale. Here, a micromachined calorimeter sensor that is capable of resolving picowatt levels of power is described. The sensor consists of low‐noise thermopiles on a thin silicon nitride membrane that allow direct differential temperature measurements between a sample and four coplanar references, which significantly reduces thermal drift. The partial pressure of water in the ambient around the sample is maintained at saturation level using a small hydrogel‐lined enclosure. The materials used in the sensor and its geometry are optimized to minimize the noise equivalent power generated by the sensor in response to the temperature field that develops around a typical sample. The experimental response of the sensor is characterized as a function of thermopile dimensions and sample volume, and its capability is demonstrated by measuring the heat dissipated during an enzymatically catalyzed biochemical reaction in a microliter‐sized liquid droplet. The sensor offers particular promise for quantitative measurements on biological systems.
TiO2 Nanowire Array Memristive Devices Emulating Functionalities of Biological Synapses
Authors: Ebenhoch Carola , Schmidt‐Mende Lukas
Published: January 2021

Memristors are deemed to be the electrical twin to biological synapses. They enable emulation of human memory functionalities such as learning, memorizing, and forgetting. The present hydrothermally grown titanium dioxide nanowire array memristive devices have shown to be able to mimic synaptic behaviors. As well as spike‐rate dependent plasticity, excitatory postsynaptic currents, and paired pulse facilitation, high endurance, and on/off ratios for the nanowire arrays are presented. Decay fitting of postsynaptic currents with Kohlrausch's equation shows lifetimes of few milliseconds up to several hundred seconds, offering the possibility of a short‐term to long‐term memory transition. Furthermore, a strong dependence of the lifetime of the signals on the frequency and amplitude of the stimulation pulses is observed.
Emerging Catalysts to Promote Kinetics of Lithium–Sulfur Batteries
Authors: Wang Peng , Xi Baojuan , Huang Man , Chen Weihua , Feng Jinkui , Xiong Shenglin
Published: January 2021

Lithium–sulfur batteries (LSBs) with a high theoretical capacity of 1675 mAh g−1 hold promise in the realm of high‐energy‐density Li–metal batteries. To cope with the shuttle effect and sluggish transformation of soluble lithium polysulfides (LiPSs), varieties of traditional metal‐based materials (such as metal, metal oxides, metal sulfides, metal nitrides, and metal carbides) with unique catalytic activity for accelerating LiPSs redox have been exploited to fundamentally inhibit the shuttle effect and improve the performance of LSBs. Concurrently, some budding catalytic materials also possess enormous potential for facilitating LiPSs redox reaction in LSBs, including metal borides, metal phosphides, metal selenides, single atoms, and defect‐engineered materials. Here, recent advances in these emerging catalytic candidates as well as the evaluation methods and parameters for catalytic materials are comprehensively summarized for the first time. New insights are also given to aid in the design of high‐performance LSBs and satisfy the high expectation in the future, including the exposure of the active sites and adsorption‐catalysis synergy strategies. Finally, the current challenges and prospects for designing highly efficient catalytic materials are highlighted, aiming at providing guidance for configuring catalytic materials to make sure high‐energy and long‐life LSBs.
Interfacial Design and Assembly for Flexible Energy Electrodes with Highly Efficient Energy Harvesting, Conversion, and Storage
Authors: Ko Yongmin , Lee Seokmin , Kwon Cheong Hoon , Lee Seung Woo , Cho Jinhan
Published: January 2021

Charge transfer between a conductive support and active materials as well as between neighboring active materials is one of the most critical factors in determining the performance of various electrodes in energy harvesting, conversion, and/or storage. Particularly, when preparing energy electrodes using conductive and/or electrochemically active nanoparticles (NPs), the bulky organic materials (i.e., ligand or polymeric binder) covering the NP surface seriously limit the charge transfer within the electrode, thereby restricting the energy storage or conversion efficiency. Furthermore, the flexibility and mechanical stability of the electrode have been considered important evaluation indices for flexible/wearable energy applications. In this regard, considerable research has been directed toward controlling the interfacial structure to enhance the charge transfer efficiency and toward incorporating functional materials into flexible/porous supports. This review describes the central progress in flexible electrodes for energy harvesting, conversion, and storage, along with the challenges in designing high‐performance energy electrodes. In particular, layer‐by‐layer (LbL) assembly is analyzed, which is an ultrathin film fabrication technology that enables fine tuning of the interfacial structure for various electrode materials. It is shown how LbL assembly can be effectively applied to energy electrodes to obtain desired functionalities and improve the charge transfer efficiency of electrodes.
Super‐Durable, Low‐Wear, and High‐Performance Fur‐Brush Triboelectric Nanogenerator for Wind and Water Energy Harvesting for Smart Agriculture
Authors: Chen Pengfei , An Jie , Shu Sheng , Cheng Renwei , Nie Jinhui , Jiang Tao , Wang Zhong Lin
Published: January 2021

The triboelectric nanogenerator (TENG), as a promising energy harvesting technology, provides a new approach for the realization of the Internet of Things (IoTs). However, material abrasion severely limits its practical applications because of the deterioration in mechanical durability and electrical stability. Here, naturally available animal furs are introduced, owing to their superiorities of extremely low wear, high performance and humidity resistance. More than 10 times the electric output is observed relative to the conventional TENG, even at low driving torque. The transferred charge of fur‐brush TENG (FB‐TENG) exhibits only 5.6% attenuation after continuous operation for 300 000 cycles, maintaining high output performance even if the relative humidity increases up to 90%. Furthermore, a counter‐rotating structure is first designed to further increase the output by doubling the relative rotation speed. Based on this mechanism, a significantly elevated output current of 36.6% is obtained in ambient conditions. Finally, self‐powered automatic irrigation, weather monitoring and wireless water level warning multifunctional management systems are realized by collecting the wind and water flow energy. This work provides a strategy of reducing wear on the premise of high performance, which lays a foundation for effective environmental energy harvesting toward practical applications in big data and the IoTs.
Materials‐Related Strategies for Highly Efficient Triboelectric Energy Generators
Authors: Choi Yeon Sik , Kim Sang‐Woo , Kar‐Narayan Sohini
Published: January 2021

Since 2012, triboelectric energy harvesting technologies have received a substantial amount of attention as they constitute one of the most efficient ways of transforming vibrational and frictional energy into electrical energy, regardless of location and environmental conditions. One of the most significant advantages of this technology is in the suitability of a very wide range of materials that can be readily incorporated into devices. In order to achieve efficient energy harvesting performance, advances in materials science and nanotechnology have been applied to develop high‐performance triboelectric energy harvesters, which have witnessed a tremendous growth in popularity. However, even though a large number of materials, including polymers, metals, inorganic and composite materials, have been separately studied for triboelectric energy harvesting applications, the key features of these different classes of materials have never been presented together or summarized, to provide valuable insight for future materials development in this field. Here, a comprehensive review of the up‐to‐date materials‐driven progress of triboelectric energy harvesting devices is provided, with emphasis on the study of materials‐related operating mechanisms and emergent materials design strategies for highly efficient triboelectric devices. The discussion includes several issues and challenges that need to be addressed for further improvement of triboelectric devices.
How might broad adoption of blockchain‐based traceability impact the U.S. fresh produce supply chain?
Authors: Collart Alba J. , Canales Elizabeth
Published: January 2021

Applications of blockchain in the food sector are growing and the adoption of farm‐to‐fork traceability systems is at the forefront. We review applications of blockchain across different dimensions while focusing on how broad adoption of the technology might help address major challenges faced by the U.S. fresh produce industry. These challenges include food safety, food fraud, food loss and waste, and the general need for better traceability systems. We discuss whether blockchain technologies might play a role in enhancing the resilience of the produce supply chain and highlight limitations and challenges of the technology stakeholders might consider going forward.

JEL CLASSIFICATION

L86; O32; Q13
Milestone achievements in a national sample of pediatric emergency medicine fellows: impact of primary residency training
Authors: Kou Maybelle , Baghdassarian Aline , Rose Jerri A. , Levasseur Kelli , Roskind Cindy G. , Vu Tien , Zuckerbraun Noel S. , Leonard Kathryn , Shabanova Veronika , Langhan Melissa L.
Published: January 2021

Background

Pediatric emergency medicine (PEM) fellowships recruit trainees from both pediatric and emergency medicine (EM) residencies. The Accreditation Council for Graduate Medical Education (ACGME) defines separate training pathways for each. The 2015 PEM milestones reflect a combination of subcompetencies from the two residencies. This project aims to compare the milestone achievement of PEM fellows based on their primary residency training. We hypothesize that fellows trained in pediatrics achieve PEM milestones at different rates than EM‐trained fellows in the ACGME domains of patient care, medical knowledge, systems‐based practice, practice‐based learning, professionalism, and interpersonal and communication skills.

Methods

This is a multicenter, retrospective cohort study of fellows from a national sample of U.S. PEM fellowship programs. Basic demographic information and deidentified, biannual milestone scores for 23 competencies were collected for fellows training between 2015 and 2018. Subcompetencies are scored on a 5‐point milestone scale. Descriptive and multivariable analyses for longitudinal data were performed to compare milestone assessments by primary residency training.

Results

Complete data were obtained for 600 fellows; 95% (570) and 5% (30) completed pediatric and EM residency, respectively. In both year 1 and year 2 of fellowship, the mean milestone scores of EM‐trained fellows were statistically higher than pediatrics‐trained fellows across the majority of subcompetencies. By the final year of training, there were no statistically significant differences in milestone scores for any of the subcompetencies.

Conclusions

Fellow milestone achievement between groups was not significantly different by graduation. However, fellows entering PEM training from an EM background attained higher scores on the milestones than fellows from a pediatric background in the first year of fellowship.
Review on unmanned aerial vehicles, remote sensors, imagery processing, and their applications in agriculture
Authors: Olson Daniel , Anderson James
Published: January 2021

Unmanned aerial vehicles (UAV) and the sensors they can be equipped with are becoming more technologically advanced and common place within the agricultural industry. The output analyses from UAV captured data helps drive decisions for improving input efficiency in agricultural systems, which can result in maximum return on investment and reduced environmental impact. Advances in UAV technologies provides producers with options for assessment of crucial factors impacting crop yield and quality including crop water status and nutrient stress, competition from weeds, insects, and pathogens, and soil characteristics and precision field maps. Thus, integrating UAV technologies as a component of production agriculture enables producers to identify and locate problem areas in their fields in near real time and take corrective actions once these areas are verified. UAV technologies also offers researchers with a non‐destructive, objective manner for obtaining phenotypic measurements such as height assessment, biomass estimation, canopy reflectance, and abiotic and biotic stress tolerance, which can greatly expedite field data collection for advancing germplasm with desired agronomic traits. This review covers more than a hundred articles that were obtained from the existing literature and illustrates common UAV types, common sensor types, imagery processing options, and their practical application and pitfalls in the modern agricultural industry.
Effect of mono‐, relay‐, and double‐crop systems on yield and profitability
Authors: Shrestha Raj K. , Richer Eric , Clevenger William B. , Davis Matthew , Lindsey Laura E.
Published: January 2021

Diversification and intensification of cropping systems are of interest due to the potential for increased farm income. However, yield and profitability of multi‐crop systems need to be understood, especially in northern environments where the growing season is short. The objective of this study was to evaluate yield and profitability of monocrop (MC), relay‐intercrop (RI), and double‐crop (DC) systems. A 3‐yr field study was conducted in northwest Ohio with nine cropping systems, including winter wheat (Triticum aestivum L.), red clover (Trifolium pretense L.), soybean (Glycine max L.), and oat (Avena sativa L.) grown in MC, RI, and DC systems. System yield was calculated by summing crop yield within a cropping year. Cropping system profitability was estimated by subtracting costs that varied across treatments from gross revenue. Winter wheat + RI red clover had the highest system yield (11.1–11.4 Mg ha−1 yr−1). However, profit was the greatest with wheat planted in wide row (38 cm row width) + RI red clover cropping system ($1,252 ha−1 yr−1) followed by wheat planted in narrow row (19 cm row width) + RI red clover ($1,140 ha−1 yr−1) and MC soybean ($919 ha−1 yr−1). This suggests that producers interested in diversifying their cropping systems may increase profitability with a winter wheat + RI red clover system, provided there is a market for red clover forage. However, if producers do not have a market for red clover, the MC soybean system would offer greatest profitability and reduce workload compared with a multi‐crop system.