bluuebunny/crossref_metadata_2025 huggingface dataset:
Solvent‐Free Synthesis of Selectively Wetting Multilayer and Janus Membranes
Authors: Cheng Christine , Gupta Malancha
Published: August 2020

In this work, the deposition of hydrophobic coatings onto porous materials is systematically studied for the fabrication of membranes with asymmetric and symmetric wetting properties. Initiated plasma‐enhanced chemical vapor deposition is used to deposit an organosilicon polymer coating onto chromatography paper of different thicknesses. The hydrophobic organosilicon polymer serves as an environmentally friendly alternative to fluorinated polymers and the all‐dry coating process does not use solvents. The deposition time, thickness of the paper, and orientation of the paper relative to the stage are shown to affect the symmetry of the wettability. The chemical functionality of the deposited polymer is characterized via Fourier‐transform infrared spectroscopy and X‐ray photoelectron spectroscopy. The hydrophobicity and wetting behavior of the coated paper are characterized with contact angle goniometry and wicking studies. Scale‐up of the process is also demonstrated by using a roll‐to‐roll module. The ability to systematically tune the wettability of materials allows for the fabrication of multilayer and Janus membranes for potential applications including filtration, smart textiles, flexible sensors, and wound dressings.
A Terahertz Chiral Metamaterial Modulator
Authors: Kindness Stephen J. , Almond Nikita W. , Michailow Wladislaw , Wei Binbin , Delfanazari Kaveh , Braeuninger‐Weimer Philipp , Hofmann Stephan , Beere Harvey E. , Ritchie David A. , Degl'Innocenti Riccardo
Published: August 2020

Active control of chirality in artificial media such as metamaterials is fundamental in many scientific areas, ranging from research into fundamental optical phenomena to the investigation of novel materials, spectroscopy, and imaging. Precise control of the light polarization states has great importance for light‐matter interaction in chemistry and biology, as media with diverse chiral properties react differently to the incoming polarization of light. In this work an active double layer metamaterial device based on vertically stacked ring resonators is realized by integrating electrostatically tunable graphene as an active element. The device is characterized with a THz time domain spectroscopic system demonstrating an all‐electrical control of circular dichroism and optical activity at ≈2 THz, reporting a tunable ellipticity of 0.55–0.98 and >20° rotation of the plane polarization, respectively, by modifying the conductivity of graphene. Further integration with a narrow frequency quantum cascade laser emitting at ≈1.9 THz, in a crossed polarizer experimental arrangement, realizes an active amplitude modulator, hence highlighting the versatility of this approach. These results represent an important milestone for the investigation of novel concepts in optics and in several applications in the THz range, such as wireless communications and spectroscopy.
Ti3C2Tx MXene Sponge Composite as Broadband Terahertz Absorber
Authors: Shui Wenchao , Li Jianmin , Wang Hao , Xing Yang , Li Yilei , Yang Qinghui , Xiao Xu , Wen Qiye , Zhang Huaiwu
Published: August 2020

Terahertz (THz) absorption technology is promising in radar stealth, electromagnetic interference (EMI) shielding, and the upcoming 6G communication. However, the most popular metamaterial‐based THz absorbers suffer from complex fabrication process and/or narrowband characteristics. Here, a broadband, lightweight, and hydrophobic THz absorber is realized based on Ti3C2Tx MXene sponge foam (MSF) that is obtained by using a dip‐coating method. Due to the macroscopic impedance matching to free space and various microscopic morphologies of metallic Ti3C2Tx flakes inside porous architecture, the obtained MSF, with only 2 mm thickness, shows almost no THz reflection (minimum ≈ 0.00003%) and high THz absorption over 99.99% under the 100% qualified frequency bandwidth ranging from 0.3 to 1.65 THz. The new strategy of combining large‐pore‐size porous architecture with MXene‐like 2D metallic flakes paves a way to achieving high performance THz absorber with minimal thickness, which is of significance in electromagnetic stealth, shielding, and beyond.
Probing the Importance of Charge Balance and Noise Current in WSe2/WS2/MoS2 van der Waals Heterojunction Phototransistors by Selective Electrostatic Doping
Authors: Ra Hyun‐Soo , Jeong Min‐Hye , Yoon Taegeun , Kim Seungsoo , Song Young Jae , Lee Jong‐Soo
Published: August 2020

Heterojunction structures using 2D materials are promising building blocks for electronic and optoelectronic devices. The limitations of conventional silicon photodetectors and energy devices are able to be overcome by exploiting quantum tunneling and adjusting charge balance in 2D p–n and n–n junctions. Enhanced photoresponsivity in 2D heterojunction devices can be obtained with WSe2 and BP as p‐type semiconductors and MoS2 and WS2 as n‐type semiconductors. In this study, the relationship between photocurrent and the charge balance of electrons and holes in van der Waals heterojunctions is investigated. To observe this phenomenon, a p‐WSe2/n‐WS2/n‐MoS2 heterojunction device with both p–n and n–n junctions is fabricated. The device can modulate the charge carrier balance between heterojunction layers to generate photocurrent upon illumination by selectively applying electrostatic doping to a specific layer. Using photocurrent mapping, the operating transition zones for the device is demonstrated, allowing to accurately identify the locations where photocurrent generates. Finally, the origins of flicker and shot noise at the different semiconductor interfaces are analyzed to understand their effect on the photoresponsivity and detectivity of unit active area (2.5 µm2, λ = 405 nm) in the p‐WSe2/n‐WS2/n‐MoS2 heterojunction device.
Optically Controllable 2D Material/Complex Oxide Heterointerface
Authors: Liu Tao , Han Cheng , Xiang Du , Han Kun , Ariando Ariando , Chen Wei
Published: August 2020

Heterostructures play a vital role in functional devices on the basis of the individual constituents. Non‐conventional heterostructures formed by stacking 2D materials onto structurally distinct materials are of great interest in achieving novel phenomena that are both scientifically and technologically relevant. Here, a heterostructure based on a 2D (molybdenum ditelluride) MoTe2 and an amorphous strontium titanium oxide (a‐STO) thin film is reported. The heterostructure functions as a high‐performance photodetector, which exhibits anomalous negative photoresponse in the pristine device due to the scattering effect from the light‐induced Oδ‐ ions. The photoresponsivity and the specific detectivity are found to be >104 AW‐1 and >1013 Jones, respectively, which are significantly higher than those in standard MoTe2 devices. Moreover, through tuning the light programming time, the photodetection behavior of the MoTe2/a‐STO heterostructure experiences a dynamic evolution from negative to positive. This is due to the optically controllable modulation of the interfacial states, which is further confirmed by the X‐ray photoelectron spectroscopy and photoluminescence measurements. It is envisioned that the 2D material/a‐STO heterostructure could be a potential platform for exploring new functional devices.
Ultrahigh Thermoelectric Power Generation from Both Ion Diffusion by Temperature Fluctuation and Hole Accumulation by Temperature Gradient
Authors: Cheng Hanlin , Ouyang Jianyong
Published: August 2020

Thermoelectric materials can be utilized to directly convert heat into electricity. This is particularly important for harvesting waste heat that is abundant on earth. But their thermoelectric performance is still not high enough for practical heat‐to‐electricity conversion after being studied for about 200 years. Instead of enhancing the figure of merit (ZT) of thermoelectric materials, a significant improvement in heat harvesting by constructing a hybrid ionic/electronic thermoelectric converter (HTEC) is demonstrated. The device consists of an electronic unit and an ionic unit. The electronic unit is made of a thermoelectric polymer, poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), and the ionic unit is composed of an ionogel. In addition to the heat‐to‐electricity conversion by the electronic unit from a temperature gradient due to the Seebeck effect, the ionic unit can generate electricity from temperature fluctuations owing to thermal ionic diffusion (Soret effect). The power generation can be many times more than the control thermoelectric generator using PEDOT:PSS. Because the temperature of waste heat usually fluctuates, the HTECs can give rise to much higher heat‐to‐electricity power conversion than normal thermoelectric generators with electronic conductors only.
Novel homozygous variant of carbonic anhydrase 8 gene expanding the phenotype of cerebellar ataxia, mental retardation, and disequilibrium syndrome subtype 3
Authors: Paternoster Lionel , Soblet Julie , Aeby Alec , De Tiège Xavier , Goldman Serge , Yue Wyatt W. , Coppens Sandra , Smits Guillaume , Vilain Catheline , Deconinck Nicolas
Published: August 2020

We report the case of an 11‐year‐old Syrian girl born to consanguineous parents, who presents an ataxic gait from early childhood. On clinical examination, she presented a severe static ‐ kinetic cerebellar syndrome, walking without support is possible for short distances only. Strikingly, three consecutive MRIs did not show any sign of cerebellar abnormalities, but a brain positron emission tomography (PET) using [18F]‐fluorodeoxyglucose (FDG) demonstrated a clear decrease in glucose metabolism in the cerebellum as well as the anterior and medial temporal lobe bilaterally. A clinical exome analysis identified a novel homozygous c.251A > G (p.Asn84Ser) likely pathogenic variant in the carbonic anhydrase 8 (CA8) gene. CA8 mutations cause cerebellar ataxia, mental retardation, and disequilibrium syndrome subtype 3 (CAMRQ3), a rare genetically autosomal recessive disorder, only described in four families, so far with the frequent observation of quadrupedal gait. The proband differed with other reported CA8 mutations by the absence of clear cerebellar signs on brain MRI and the presence of focal seizures. This report expands the clinical spectrum associated with mutations in CA8 and illustrates the possible discrepancy between (mild) neuro‐radiological images (MRI) and (severe) clinical phenotype in young individuals. In contrast, the observation of clear cerebellar abnormal metabolic findings suggests that the FDG‐PET scan may be used as an early marker for hereditary ataxia.
Multidisciplinary aortopathy clinics: A systematic scoping review of the literature and evaluation of patient experiences from a newly started clinic in Norway
Authors: Bathen Trine , Krohg‐Sørensen Kirsten , Lidal Ingeborg B.
Published: August 2020

Background

International guidelines recommend hereditary thoracic aortic diseases (HTADs) to be managed in multidisciplinary aorta clinics.

Aim

To study HTAD patient's experiences with a aortopathy clinic in Norway and to review the literature on aortopathy clinics.

Methods

(a) A systematic scoping review of research on multidisciplinary clinics for HTADs. (b) A cross‐sectional postal questionnaire study to investigate patient experiences with the health‐services. Fifty consecutive patients from the aortopathy clinic and 50 controls in usual care were invited to participate.

Results

The review identified eight publications on aortopathy clinics. Although the papers were not judged for quality, these showed promising results from such clinics in terms of diagnostics and increased adherence to guideline‐directed therapy. The survey constituted thirty‐seven (74%) patients and 22 (44%) controls who responded to postal questionnaires. Both groups reported delays in diagnostics and follow‐up appointments prior to the start of the clinic. Patients indicated high satisfaction with the aortopathy clinic, whereas controls reported poor coordination of medical follow‐up. Individuals in both groups struggled with disease self‐management.

Conclusion

Norwegian patient experiences found the aortopathy clinic beneficial. According to studies included in the review, disease management in aortopathy clinics may improve patient satisfaction, diagnostics and follow‐up. Effect studies may further document the benefits of clinic organization, treatment, cost‐efficiency and patient experiences.
Feet‐to‐Feet‐Connected Multitopic Resorcinarene Macrocycles
Authors: Shimoyama Daisuke , Haino Takeharu
Published: August 2020

The past three decades have witnessed extraordinary advances in the preparation of macrocycles from a resorcinarene platform. Bridging two or more resorcinarene units through multipoint connections produces multitopic resorcinarene‐based hosts. The unique properties arising from multivalency offer diverse applications, such as molecular flasks, molecular machines, and supramolecular polymers. The face‐to‐face connection of two or more resorcinarenes results in a convergent, expanded guest binding space in which many large guests can be accommodated. In contrast, the feet‐to‐feet connection provides an extroverted, ditopic feature that can lead to different applications. Herein, we highlight the synthesis of extroverted, multitopic resorcinarene macrocycles and discuss their fascinating functions, such as molecular recognition, allosteric guest binding, and supramolecular polymerization.
Validation and utility of a body condition scoring system for chimpanzees (Pan troglodytes)
Authors: Reamer Lisa A. , Neal Webb Sarah J. , Jones Rebekah , Thiele Erica , Haller Rachel L. , Schapiro Steven J. , Lambeth Susan P. , Hanley Patrick W.
Published: August 2020

Obesity is a problem in captive chimpanzee colonies that can lead to increased risk for disease; therefore, implementation of effective weight management strategies is imperative. To properly implement a weight management program, captive managers should be able to noninvasively identify and assess overweight or obese individuals. Traditional means of categorizing obese individuals involve sedating the animals to obtain body weights or skin fold measurements. The current study aimed to validate a noninvasive, subjective body condition score (BCS) system for captive chimpanzees. The system utilizes a 10‐point scale, with one rated as “emaciated,” five as “normal,” and 10 as “extremely obese.” Between 2013 and 2014, 158 chimpanzees were weighed and scored using this system (a) while sedated and (b) while awake in their social group within 1–3 days of sedation (“In‐group” ratings). We found high inter‐rater reliability between In‐group raters, as well as between sedated and In‐group scores. BCSs, which require observation only, were significantly positively correlated with weight (an objective measure of obesity often requiring anesthetization), supporting the scale's validity. The BCS system identified 36 individuals as “overweight,” while the use of weights alone identified only 26 individuals as “overweight.” Furthermore, the BCS system was able to classify individuals of the same sex and weight as having different BCSs, ranging from normal to overweight. Lastly, using focal animal behavioral observations from 2016 to 2018 (N = 120), we found that In‐group BCS predicted individual levels of inactive behavior more than 2 years later, demonstrating the predictive validity of the scale. These results illustrate the utility of the BCS system as a noninvasive, reliable, and valid technique that may be more sensitive than traditional methods in identifying and quantifying obesity in chimpanzees. This system can be a useful tool for captive managers to monitor and manage the weight of chimpanzees and other nonhuman primates.
Ontogenetic changes in magnitudes of integration in the macaque skull
Authors: Jung Hyunwoo , Simons Evan , von Cramon‐Taubadel Noreen
Published: August 2020

Objectives

Magnitudes of morphological integration may constrain or facilitate craniofacial shape variation. The aim of this study was to analyze how the magnitude of integration in the skull of Macaca fascicularis changes throughout ontogeny in relation to developmental and/or functional modules.

Materials and methods

Geometric morphometric methods were used to analyze the magnitude of integration in the macaque cranium and mandible in 80 juvenile and 40 adult M. fascicularis specimens. Integration scores in skull modules were calculated using integration coefficient of variation (ICV) of eigenvalues based on a resampling procedure. Resultant ICV scores between the skull as a whole, and developmental and/or functional modules were compared using Mann–Whitney U tests.

Results

Results showed that most skull modules were more tightly integrated than the skull as a whole, with the exception of the chondrocranium in juveniles without canines, the chondrocranium/face complex and the mandibular corpus in adults, and the mandibular ramus in all juveniles. The chondrocranium/face and face/mandibular corpus complexes were more tightly integrated in juveniles than adults, possibly reflecting the influences of early brain growth/development, and the changing functional demands of infant suckling and later masticatory loading. This is also supported by the much higher integration of the mandibular ramus in adults compared with juveniles.

Discussion

Magnitudes of integration in skull modules reflect developmental/functional mechanisms in M. fascicularis. However, the relationship between “evolutionary flexibility” and developmental/functional mechanisms was not direct or simple, likely because of the complex morphology, multifunctionality, and various ossification origins of the skull.
Did Neandertals have large brains? Factors affecting endocranial volume comparisons
Authors: VanSickle Caroline , Cofran Zachary , Hunt David
Published: August 2020

Objectives

Common wisdom in paleoanthropology is that Neandertals had bigger brains than recent humans. Here we tested the hypothesis that there is no difference in brain size between Neandertals and recent humans while accounting for methodological variation and the makeup of both the Neandertal and recent human samples.

Materials and Methods

We examined endocranial volume (ECV) derived from virtually reconstructed endocasts of 11 Neandertals, six of which had associated femoral head diameters (FHD). Our recent human comparative dataset consisted of virtually measured ECV and associated FHD from 94 recent humans from the Robert J. Terry Anatomical Collection (63 male, 31 female). ECV of Neandertals and recent humans was compared using bootstrap resampling, repeating the analysis for two groupings of Neandertals (all and classic) and for three groupings of recent humans (all, males, and females). To examine brain size scaling, we completed an ordinary least squares regression of log (ECV) against log (FHD) for Neandertals and recent humans.

Results

The results of the bootstrap resampling analyses indicated that Neandertals only had significantly larger ECV when compared with recent human females. The regression between ECV and FHD suggested that Neandertals fall within the range of variation for larger humans.

Discussion

Our results demonstrate that Neandertals do not have uniquely large brains when compared with recent humans. Their brain size falls in the large end of the recent human range of variation, but does not exceed it. These results have implications for future research on Neandertal encephalization.
Preparing the health‐care system to pay for new Alzheimer's drugs
Authors: Lin Pei‐Jung , Cohen Joshua T. , Neumann Peter J.
Published: August 2020

Biogen's announcement last fall that it will seek U.S. Food and Drug Administration approval for its Alzheimer's disease (AD) treatment, aducanumab, 7 months after the drug was declared a failure, buoyed patients and families, but put health payers and policymakers on alert. Whether aducanumab succeeds, other disease‐modifying therapies for AD will follow, and the health‐care system is unprepared for the reimbursement and access challenges. Novel AD therapies are much needed, but we cannot assume substantial cost offsets. With forethought and preparation, however, the health‐care system can accommodate new AD drugs. First, we urge the use of cost‐effectiveness of new Alzheimer's treatments as a starting point for setting value‐based prices. Second, payments for new AD therapies should ideally incorporate a performance warranty, which helps apportion risk associated with initial therapy value estimates between drug manufacturers and payers. Third, we urge consideration of “subscription” payment agreements to address system affordability issues.
A Robust Au−C≡C Functionalized Surface: Toward Real‐Time Mapping and Accurate Quantification of Fe2+ in the Brains of Live AD Mouse Models
Authors: Zhang Chuanping , Liu Zhichao , Zhang Limin , Zhu Anwei , Liao Fumin , Wan Jingjing , Zhou Jian , Tian Yang
Published: August 2020

Described here is that Au−C≡C bonds showed the highest stability under biological conditions, with abundant thiols, and the best electrochemical performance compared to Au−S and Au−Se bonds. The new finding was also confirmed by theorical calculations. Based on this finding, a specific molecule for recognition of Fe2+ was designed and synthesized, and used to create a selective and accurate electrochemical sensor for the quantification of Fe2+. The present ratiometric strategy demonstrates high spatial resolution for real‐time tracking of Fe2+ in a dynamic range of 0.2–120 μM. Finally, a microelectrode array with good biocompatibility was applied in imaging and biosensing of Fe2+ in the different regions of live mouse brains. Using this tool, it was discovered that the uptake of extracellular Fe2+ into the cortex and striatum was largely mediated by cyclic adenosine monophosphate (cAMP) through the CREB‐related pathway in the brain of a mouse with Alzheimer's disease.
Interfacial Strain Release from the WS2/CsPbBr3 van der Waals Heterostructure for 1.7 V Voltage All‐Inorganic Perovskite Solar Cells
Authors: Zhou Qingwei , Duan Jialong , Yang Xiya , Duan Yanyan , Tang Qunwei
Published: August 2020

Perovskite lattice distortion induced by residual tensile strain from the thermal expansion mismatch between the electron‐transporting layer (ETL) and perovskite film causes a sluggish charge extraction and transfer dynamics in all‐inorganic CsPbBr3 perovskite solar cells (PSCs) because of their higher crystallization temperatures and thermal expansion coefficients. Herein, the interfacial strain is released by fabricating a WS2/CsPbBr3 van der Waals heterostructure owing to their matched crystal lattice structure and the atomically smooth dangling bond‐free surface to act as a lubricant between ETL and CsPbBr3 perovskite. Arising from the strain‐released interface and condensed perovskite lattice, the best device achieves an efficiency of 10.65 % with an ultrahigh open‐circuit voltage of 1.70 V and significantly improved stability under persistent light irradiation and humidity (80 %) attack over 120 days.
Structural Phase Transitions of a Molecular Metal Oxide
Authors: Fujibayashi Masaru , Watari Yu , Tsunashima Ryo , Nishihara Sadafumi , Noro Shin‐ichiro , Lin Chang‐Gen , Song Yu‐Fei , Takahashi Kiyonori , Nakamura Takayoshi , Akutagawa Tomoyuki
Published: August 2020

The structural phase of a metal oxide changes with temperature and pressure. During phase transitions, component ions move in multidimensional metal–oxygen networks. Such macroscopic structural events are robust to changes in particle size, even at scales of around 10 nm, and size effects limiting these transitions are particularly important in, for example, high‐density memory applications of ferroelectrics. In this study, we examined structural transitions of the molecular metal oxide [Na@(SO3)2(n‐BuPO3)4MoV4MoVI14O49]5− (Molecule 1) at approximately 2 nm by using single‐crystal X‐ray diffraction analysis. The Na+ encapsulated in the discrete metal‐oxide anion exhibited a reversible order–disorder transition with distortion of the Mo–O molecular framework induced by temperature. Similar order–disorder transitions were also triggered by chemical pressure induced by removing crystalline solvent molecules in the single‐crystal state or by substituting the countercation to change the molecular packing.
Cellular‐ and Subcellular‐Targeted Delivery Using a Simple All‐in‐One Polymeric Nanoassembly
Authors: Gao Jingjing , Dutta Kingshuk , Zhuang Jiaming , Thayumanavan S.
Published: August 2020

Nanocarrier‐mediated drug delivery is a promising strategy to maximize the power of chemotherapy and minimize side effects. However, current approaches show insufficient drug‐loading capacity and inefficient drug release, and require complex modification processes. Attempts to enhance one of these features often compromise other merits. We describe here a block copolymer assembly system that combines desirable characteristics. The design of self‐immolative and crosslinkable hydrophobic moieties offer stable and high encapsulation. Redox‐triggerable polymer self‐immolation promotes drug release by switching the hydrophobic core into completely hydrophilic chains. The reactive amine handles, presented on their surface, allow “plug to direct” modification with targeting ligands. Functionalized nanoassemblies have been programmed to target specific subcellular compartments. The simplicity, versatility, and efficacy of the system open up possibilities for an all‐in‐one delivery system.
A Two‐Dimensional Metal–Organic Polymer Enabled by Robust Nickel–Nitrogen and Hydrogen Bonds for Exceptional Sodium‐Ion Storage
Authors: Wang Liubin , Ni Youxuan , Hou Xuesen , Chen Li , Li Fujun , Chen Jun
Published: August 2020

Organic electrode materials suffer from low electronic conductivity and poor structure stability. Herein, a metal–organic polymer, Ni‐coordinated tetramino‐benzoquinone (Ni‐TABQ), is synthesized via d–π hybridization. The polymer chains are stitched by hydrogen bonds to feature as a robust two‐dimensional (2D) layered structure. It offers both electron conduction and Na+ diffusion pathways along the directions of the polymer chains and the hydrogen bonds. With both the conjugated benzoid carbonyls and imines as the redox centers for the insertion and extraction of Na+, the Ni‐TABQ delivers high capacities of about 469.5 mAh g−1 at 100 mA g−1 and 345.4 mAh g−1 at 8 A g−1. The large capacities are sustained for 100 cycles with almost 100 % coulombic efficiencies. The exceptional electrochemical performance is attributed to the unique 2D electron conduction and Na+ diffusion pathways enabled by the robust Ni–N and hydrogen bonds.
Suppressing Strong Exciton–Phonon Coupling in Blue Perovskite Nanoplatelet Solids by Binary Systems
Authors: Peng Shaomin , Wei Qi , Wang Bingzhe , Zhang Zhipeng , Yang Hongcheng , Pang Guotao , Wang Kai , Xing Guichuan , Sun Xiao Wei , Tang Zikang
Published: August 2020

Quasi‐two‐dimensional (2D) perovskites are promising candidates for light generation owing to their high radiative rates. However, strong exciton–phonon interactions caused by mechanical softening of the surface act as a bottleneck in improving their suitability for a wide range of lighting and display applications. Moreover, it is not easily available to tune the phonon interactions in bulk films. Here, we adopt bottom‐up fabricated blue emissive perovskite nanoplatelets (NPLs) as model systems to elucidate and as well as tune the phonon interactions via engineering of binary NPL solids. By optimizing component domains, the phonon coupling strength can be reduced by a factor of 2 driven by the delocalization of 2D excitons in out‐of‐plane orientations. It shows the picosecond energy transfer originated from the Förster resonance energy transfer (FRET) efficiently competes with the exciton–phonon interactions in the binary system.
Continuous Tuning of Au–Cu2O Janus Nanostructures for Efficient Charge Separation
Authors: Xu Wenjia , Jia Jia , Wang Ti , Li Chao , He Bowen , Zong Jianpeng , Wang Yawen , Fan Hong Jin , Xu Hongxing , Feng Yuhua , Chen Hongyu
Published: August 2020

In photocatalysis, the Schottky barrier in metal–semiconductor hybrids is known to promote charge separation, but a core–shell structure always leads to a charge build‐up and eventually shuts off the photocurrent. Here, we show that Au–Cu2O hybrid nanostructures can be continuously tuned, particularly when the Cu2O domains are single‐crystalline. This is in contrast to the conventional systems, where the hybrid configuration is mainly determined by the choice of materials. The distal separation of the Au–Cu2O domains in Janus nanostructures leads to enhanced charge separation and a large improvement of the photocurrent. The activity of the Au–Cu2O Janus structures is 5 times higher than that of the core–shell structure, and 10 times higher than that of the neat Cu2O nanocubes. The continuous structural tuning allows to study the structure–property relationship and an optimization of the photocatalytic performance.
Synthesis, characterization, X‐ray structure, electrochemistry, photocatalytic activity and DFT studies of heterotrinuclear Ni(II), Pd(II) and Zn(II) complexes containing a formylferrocene thiosemicarbazone ligand
Authors: Chung Patricio , Huentupil Yosselin , Rabanal Walter , Cisterna Jonathan , Brito Iván , Arancibia Rodrigo
Published: August 2020

Three complexes of the general formula M{CpFe(η5‐C5H4CH=N–N=C(S)NH2}2 [where M = NiII (2a), PdII (2b) and ZnII (2c)] were synthesized with formylferrocene thiosemicarbazone (1) as a bidentate ligand. All compounds were characterized using conventional spectroscopic and analytical techniques (infrared, 1H and 13C NMR, mass spectrometry and elemental analysis). The molecular structure of 2b was confirmed by single‐crystal X‐ray analysis. To study the photocatalytic activity of the new complexes (2a–c), methylene blue (MB) was selected as a model pollutant. After 180 min, the degradation efficiency of MB reached 87% for 2a, 76% for 2b and 85% for 2c, and all complexes showed a higher photocatalytic activity than the formylferrocene thiosemicarbazone free ligand 1. Theoretical studies were used to characterize the geometry and electronic structure of the compounds and to provide a rational explanation for the measured photocatalytic activity.
3D printing of copper particles and poly(methyl methacrylate) beads containing poly(lactic acid) composites for enhancing thermomechanical properties
Authors: Vu Minh Canh , Jeong Tae‐Hyeong , Kim Jun‐Beom , Choi Won Kook , Kim Dae Hoon , Kim Sung‐Ryong
Published: August 2020

Poly(lactic acid) (PLA) composite filaments with different copper (Cu) contents as high as 40 and 20 wt% of poly(methyl methacrylate) (PMMA) beads have been fabricated by twin‐screw extruder for 3D printing. A fused‐deposition modeling (FDM) 3D printing technology has been used to print the PLA composites containing hybrid fillers of Cu particles and PMMA beads. The morphology, mechanical, and thermal properties of the printed PLA composites were investigated. The tensile strength was slightly decreased, but storage modulus and thermal conductivity of PLA composites were significantly improved by adding Cu particles in the presence of PMMA beads. The PLA composites with hybrid fillers of 40 wt% of Cu particles and 20 wt% of PMMA beads resulted in thermal conductivity of 0.49 W m−1 K−1 which was three times higher than that of the bare PLA resin. The facilitation of the segregated network of high‐thermally conductive Cu particles with the PMMA beads in PLA matrix provided thermally conductive pathways and resulted in a remarkable enhancement in thermal conductivity.
Transparency‐tunable and moderate‐temperature healable thermoplastic polyurethane elastomer based on bisphenol A chain‐extender
Authors: Xiang Chuanxi , Chen Hongxiang , Wang Wanwan , Dai Qiaoli , Liu Zhiqiang , Yang Bing , Zhou Yu , Zhou Yang
Published: August 2020

Transparent self‐healing polymers have a promising future, but the research on the relationship among transparency, self‐healing, and structure is still challenging. The thermoplastic polyurethane elastomers containing aryl carbamate were prepared by the reaction of isocyanate‐terminated prepolymer and chain‐extender bisphenol A (BPA). On the one hand, the thermoplastic polyurethane elastomer could heal at a relatively low temperature due to the exchange of aryl carbamate, and exhibits 83% of healing efficiency at 90°C for 2 h. On the other hand, two methyl groups of BPA hinder the crystallization of hard segments in polyurethane, so the domain of hard segments is amorphous, while the microcrystals of soft segments dispersed in the polyurethane are affected by the content of hard segments, therefore, the transparency of polyurethane can be tailored by the content of hard segments. It provides a simple design and a feasible preparation method for transparent self‐healing polymer.
Are Anatomy PhDs Nearing Extinction or Adapting to Change? United States Graduate Education Trends in the Anatomical Sciences
Authors: Wilson Adam B. , Kaza Niroop , Singpurwalla Darius J. , Brooks William S.
Published: August 2020

Faculty qualified to teach in the anatomical sciences are growing scarce just as the need for trained anatomists is greater than ever. Enrollments are surging in anticipation of a large physician shortfall; meanwhile, many anatomists are reaching retirement age. Who will fill the teaching gap? This study assessed trends in doctorates awarded in Anatomy and related fields within the United States (US) since 1969 and evaluated modern graduate education in the anatomical sciences. Data were compiled from the National Science Foundation Survey of Earned Doctorates. The total number of doctorates in the anatomical sciences and number of doctorates by sex and race/ethnicity were plotted for trend analysis. The number of PhD anatomy training programs within US medical schools was also assessed. Curricula and major characteristics of all active programs were evaluated through website searches and program director interviews. While doctorates in cell biology, developmental biology, and neuroscience have grown, the number of PhDs awarded in Anatomy has declined, on average, by 3.1 graduates per year to a 50‐year low of only 8 graduates in 2017. Currently, 21 active doctoral programs in anatomy operate within US medical schools and fall into three general categories: anatomy education (n = 8), classic anatomy (n = 8), and anthropology/evolutionary anatomy (n = 5). Without a concerted effort by stakeholders to address the shortage, anatomists may face extinction. Expansion of the anatomy education doctoral degree may represent a necessary evolution of the field to meet job market needs and to thwart the extinction threat.
Verbal aptitude hurts children's economic decision‐making accuracy
Authors: Bruyneel Sabrina , Cherchye Laurens , Cosaert Sam , De Rock Bram , Dewitte Siegfried
Published: August 2020

The impact of children's decision making increases with age and has relatively increased through time. Although a lot is known about cognitive development, less is known about how this development impacts decision accuracy in economic situations. This study builds on revealed preference theory to study the impact of cognitive aptitude on economic decision‐making accuracy and explores the intervening role of decision heuristics. In a study (n = 100) where children from three age groups had to make choices between combinations of products, we found that decision accuracy was lower for kindergarteners than for children from the third and sixth grade, replicating and validating older findings. We found that one aspect of cognitive aptitude, namely, verbal aptitude, hurts rather than helps decision accuracy. Further explorations suggested that this relation was due to the decreased use of the “more is better” heuristic, a child's preference for options with many units, which decreased with increasing verbal aptitude but increased rational decision making. We discuss the implications of the negative effect of verbal aptitude on economic decision‐making accuracy.
Using online simulations to teach biochemistry laboratory content during COVID‐19
Authors: Costabile Maurizio
Published: August 2020

At the University of South Australia (UniSA), Biochemistry is a second year undergraduate course. The student cohort is diverse, with students enrolled in courses with a laboratory focus, such as Laboratory Medicine, Medical Science, Nutrition and Food Science and Pharmaceutical Science. The course is taught in a traditional manner, with weekly lectures, fortnightly tutorials and three practical sessions. In response to the growing numbers of COVID‐19 cases, in mid‐March the University leadership moved to cease face‐to‐face teaching. By this time, 58 of 96 students had completed the first two (of three) face‐to‐face laboratory practicals. In response to this decision, teaching of all practical based content was moved online for all students. The first question was, how do we teach practical content online? And secondly, how do we teach hands‐on skills? The first question was addressed using a suite of online simulations, progressively developed since 2013. Simulations are widely used and shown to be useful as teaching aids in STEM. A total of five simulations were introduced each covering key aspects of laboratory practice, including fundamental mathematical skills, reading, and setting a pipette, basic Biochemistry assays, protein quantification, and enzyme kinetics. The second issue of teaching hands on skills was addressed once restrictions were eased. Students were invited to attend the laboratory to learn the kinesthetic skills with instructor guidance. Both approaches used proved to be highly effective and can be readily adapted not only to teaching Biochemistry, but any aspect of science education.
Applying active learning in a virtual classroom such as a molecular biology escape room
Authors: Alonso Gabriela , Schroeder Kersten T.
Published: August 2020

The transition to remote‐teaching online for Molecular Biology has forced active learning exercises like Escape Rooms to also move online. In the past, Escape Rooms have been an effective tool for students to help reinforce concepts they learned in Molecular Biology. We propose that there is a way for Escape Rooms to be moved to an online setting and still be an effective avenue for students to learn the material in a fun and interactive way.
A lab‐on‐a‐chip model of glaucoma
Authors: Nafian Fatemeh , Kamali Doust Azad Babak , Yazdani Shahin , Rasaee Mohammad Javad , Daftarian Narsis
Published: August 2020

Aims

We developed a glaucoma‐on‐a‐chip model to evaluate the viability of retinal ganglion cells (RGCs) against high pressure and the potential effect of neuroprotection.

Methods

A three‐layered chip consisting of interconnecting microchannels and culture wells was designed and fabricated from poly‐methyl methacrylate sheets. The bottom surface of the wells was modified by air plasma and coated with different membranes to provide a suitable extracellular microenvironment. RGCs were purified from postnatal Wistar rats by magnetic assisted cell sorting up to 70% and characterized by flow cytometry and immunocytochemistry. The cultured RGCs were exposed to normal (15 mmHg) or elevated pressure (33 mmHg) for 6, 12, 24, 36, and 48 hr, with and without adding brain‐derived neurotrophic factor (BDNF) or a novel BDNF mimetic (RNYK).

Results

Multiple inlet ports allow culture media and gas into the wells under elevated hydrostatic pressure. PDL/laminin formed the best supporting membrane. RGC survival rates were 85%, 78%, 70%, 67%, and 61% under normal pressure versus 40%, 22%, 18%, 12%, and 10% under high pressure at 6, 12, 24, 36, and 48 hr, respectively. BDNF and RNYK separately reduced RGC death rates about twofold under both normal and elevated pressures.

Conclusion

This model recapitulated the effects of elevated pressure over relatively short time periods and demonstrated the neuroprotective effects of BDNF and RNYK.
Behavioral changes and gene profile alterations after chronic 1,950‐MHz radiofrequency exposure: An observation in C57BL/6 mice
Authors: Jeong Ye Ji , Son Yeonghoon , Choi Hyung‐Do , Kim Nam , Lee Yun‐Sil , Ko Young‐Gyu , Lee Hae‐June
Published: August 2020

Introduction

Due to public concerns about deleterious biological consequences of radiofrequency electromagnetic fields (RF‐EMF), the potential effects of RF‐EMF on the central nervous system have received wide consideration.

Methods

Here, two groups of C57BL/6 mice, aged 2 and 12 months, were exposed to 1,950‐MHz RF‐EMF at a specific absorption rate of 5.0 W/kg for chronic periods (2 hr/day and 5 days/week for 8 months). Behavioral changes were then assessed in the mice at 10 months (sham‐ or RF‐10M) and 20 months (sham‐ or RF‐20M), on the open‐field test, the Y‐maze test, and an object recognition memory task, while biological effects were analyzed via microarray gene profiling of the hippocampus.

Results

Open‐field test results showed a decrease in the time duration spent at the center while there was a decrease in enhanced memory shown by the Y‐maze test and the novel object recognition test in the RF‐20M mice, compared to sham‐exposed mice, but no significant changes in the RF‐10M group. Based on a 2‐fold change cutoff, the microarray data revealed that 15 genes, which are listed as being involved in neurogenesis on Gene Ontology, were altered in both groups. Quantitative real‐time PCR for validation showed increased expression of Epha8 and Wnt6 in the hippocampi of RF‐20M group mice, although 13 additional genes showed no significant changes following RF‐EMF exposure.

Conclusion

Therefore, cognitive enhancement following chronic exposure for 8 months to RF‐EMF from middle age may be associated with increases in neurogenesis‐related signals in the hippocampus of C57BL/6 mice.
Advancing preuniversity students' computational thinking skills through an educational project based on tangible elements and virtual block‐based programming
Authors: Trilles Sergio , Granell Carlos
Published: August 2020

University students enroling in Science, Technology, Engineering and Mathematics (STEM)‐related studies such as computer science continue to decline, even though worldwide educational policy reports warn about the need for this type of professionals in the immediate future. Promoting computer science studies among preuniversity students seems the most direct solution to reverse this issue. In this context, we present the Sucre4Kids project whose main objectives are to engage young people into computational thinking and programming concepts using tangible elements and social interaction. We apply the Sucre4Kids approach to introductory courses of computational thinking and programming concepts to high‐school students. The main results of the 3‐year intervention in the classroom with 256 high‐school students reached suggest that tangible elements and social interaction in groups are determining factors in increasing students' motivation to learn to code and to raise their interest in STEM disciplines.
Paperclickers: Affordable solution for classroom response systems
Authors: de Oliveira Eduardo , Bindá Jomara , Valle Eduardo , Lopes Renato
Published: August 2020

We propose paperclickers, a low‐cost classroom response system requiring a single mobile device for the teacher and cards with printed codes for the students, which results in a low‐cost, easy‐to‐deploy solution that aims at broadening the adoption of active learning techniques in developing countries. We implemented paperclickers as a smartphone application, whose development history, with pitfalls and lessons learned, we describe in this paper. We also describe the results of the first round of usability tests we performed on the first prototype, indicating the feasibility of paperclickers, the opportunities for design improvement, and how they affected the current version of the software. A beta release of paperclickers is available for the public.
Which patients to sample in clinical cohort studies when the number of events is high and measurement of additional markers is constrained by limited resources
Authors: Edelmann Dominic , Ohneberg Kristin , Becker Natalia , Benner Axel , Schumacher Martin
Published: August 2020

Purpose

We consider an existing clinical cohort with events but limited resources for the investigation of a further potentially expensive marker. Biological material of the patients is stored in a biobank, but only a limited number of samples can be analyzed with respect to the marker. The question arises as to which patients to sample, if the number of events preclude standard sampling designs.

Methods

Modifications of the nested case‐control and the case‐cohort design for the proportional hazards model are applied, that allow efficient sampling in situations where standard nested case‐control and case‐cohort are not feasible. These sampling designs are compared to simple random sampling and extreme group sampling, the latter including only patients with extreme outcomes, ie either with an event early in time or without an event until at least a point later in time.

Results

The modified nested case‐control design and the modified case‐cohort design provide powerful methods for sampling in a clinical cohort with many events. The simple random sampling usually is less efficient. If focus is on precise estimation of a potential effect in terms of a hazard ratio, extreme group sampling is not competitive. If focus is on screening for important biomarkers, extreme group sampling markedly outperforms the other sampling designs.

Conclusions

When it is not feasible to sample all events, a modified nested case‐control design or case‐cohort design leads to efficient effect estimates in the proportional hazards model. If screening for important biomarkers is the primary objective, extreme group sampling is preferable.
Reduced liver cancer mortality with regular clinic follow‐up among patients with chronic hepatitis B: A nationwide cohort study
Authors: Shim Jae‐Jun , Kim Gi‐Ae , Oh Chi Hyuk , Kim Jung Wook , Myung Jisun , Kim Byung‐Ho , Oh In‐Hwan
Published: August 2020

Background

Regular clinic follow‐up is a prerequisite for optimal antiviral therapy and surveillance of hepatocellular carcinoma in patients with chronic hepatitis B (CHB). However, adherence to regular follow‐up stays low in practice. This study investigated whether regular follow‐up is associated with decreased liver cancer mortality in CHB patients.

Methods

A nationwide population‐based historical cohort study was conducted using customized data from the National Health Insurance Service of Korea. The number of hospital visits every 3‐month interval was counted for 2 years from the date of CHB diagnosis. Patients were classified into three follow‐up groups: regular (four to eight visits), irregular (one to three visits), and no follow‐up. The risk of liver cancer mortality was compared among the groups using Cox proportional hazard regression analysis.

Results

Of the 414 074 CHB patients, 22.9% had regular follow‐up. In multivariable analysis, regular follow‐up was independently associated with decreased risk of liver cancer mortality compared to no follow‐up (hazard ratio [HR], 0.56; 95% confidence interval [CI], 0.50‐0.63, P < .001). Regular follow‐up was also associated with the lowest risk of all‐cause mortality (HR, 0.60; 95% CI, 0.57‐0.63, P < .001). Patients with regular follow‐up received more curative treatment (23.1% vs 15.1%, P < .001). Patients were less motivated when they were female, >60 years, of low socioeconomic status, disabled, lived in a rural area, had a higher comorbidity rate, or did not have cirrhosis.

Conclusions

Regular follow‐up at least every 3‐6 months is significantly associated with reduced liver cancer mortality in patients with CHB.