bluuebunny/crossref_metadata_2025 huggingface dataset:
Significance of Nanomaterials in Wearables: A Review on Wearable Actuators and Sensors
Authors: Jayathilaka Wanasinghe Arachchige Dumith Madushanka , Qi Kun , Qin Yanli , Chinnappan Amutha , Serrano‐García William , Baskar Chinnappan , Wang Hongbo , He Jianxin , Cui Shizhong , Thomas Sylvia W. , Ramakrishna Seeram
Published: December 2018

Together with the evolution of digital health care, the wearable electronics field has evolved rapidly during the past few years and is expected to be expanded even further within the first few years of the next decade. As the next stage of wearables is predicted to move toward integrated wearables, nanomaterials and nanocomposites are in the spotlight of the search for novel concepts for integration. In addition, the conversion of current devices and attachment‐based wearables into integrated technology may involve a significant size reduction while retaining their functional capabilities. Nanomaterial‐based wearable sensors have already marked their presence with a significant distinction while nanomaterial‐based wearable actuators are still at their embryonic stage. This review looks into the contribution of nanomaterials and nanocomposites to wearable technology with a focus on wearable sensors and actuators.
Direct Observation of Nanoscale Light Confinement without Metal
Authors: Liu Yunxin , Vanacken Johan , Chen Xianmei , Han Junbo , Zhong Zhiqiang , Xia Zhengcai , Chen Borong , Wu Huan , Jin Zhao , Ge Jun‐Yi , Huang Junwei , Meng Lei , Duan Xiangfeng , Huang Yu , Peng Qing , Moshchalkov Victor V. , Li Yadong
Published: December 2018

Manipulation of light below the diffraction limit forms the basis of nanophotonics. Metals can confine light at the subwavelength scale but suffer from high loss of energy. Recent reports have theoretically demonstrated the possibility of light confinement below the diffraction limit using transparent dielectric metamaterials. Here, nanoscale light confinement (<λ/20) in transparent dielectric materials is shown experimentally through a luminescent nanosystem with rationally designed dielectric claddings. Theoretically, green light with a wavelength of 540 nm has a transmission of 98.8% when passing through an ultrathin NaYF4/NaGdF4 superlattice cladding (thickness: 6.9 nm). Unexpectedly, the complete confinement of green emission (540 nm) by such an ultrathin dielectric cladding is directly observed. FDTD calculations are used to confirm that the ultrathin dielectric cladding has negligible influence on the transmission of propagating light, but extraordinary confinement of evanescent waves. This will provide new opportunities for nanophotonics by completely averting the use of metals.
Mechanically Excited Multicolor Luminescence in Lanthanide Ions
Authors: Du Yangyang , Jiang Yue , Sun Tianying , Zhao Jianxiong , Huang Bolong , Peng Dengfeng , Wang Feng
Published: December 2018

Mechanoluminescence (ML) featuring photon emission by mechanical stimuli is promising for applications such as stress sensing, display, and artificial skin. However, the progress of utilizing ML processes is constrained by the limited range of available ML emission spectra. Herein, a general strategy for expanding the emission of ML through the use of lanthanide emitters is reported. A lithium‐assisted annealing method for effective incorporation of various lanthanide ions (e.g., Tb3+, Eu3+, Pr3+, Sm3+, Er3+, Dy3+, Ho3+, Nd3+, Tm3+, and Yb3+) into CaZnOS crystals that are identified as one of the most efficient host materials for ML is developed. These doped CaZnOS crystals show efficient and tunable ML spanning full spectrum from violet to near infrared. The multicolor ML materials are used to create encrypted anticounterfeiting patterns, which produce spatially resolvable optical codes under single‐point dynamic pressure of a ballpoint pen.
Layer‐by‐Layer Assembled g‐C3N4 Nanosheets/Cellulose Nanofibers Oriented Membrane‐Filler Leading to Enhanced Thermal Conductivity
Authors: Wu Bin , Ge Liang , Wu Han , Wang Xin , Ge Qianqian , Miao Jibin , Cao Ming , Chen Peng , Xia Ru , Qian Jiasheng
Published: December 2018

Thermally conducting but electrically insulating materials attract much attention because of miniaturization and high‐degree integration of modern electronic. The traditional approaches to prepare the thermally conductive polymer nanocomposites are usually influenced by the low thermal conductivity, deterioration of electrically insulating, and high filler amount. One of the main reasons is that the filler is impossible to construct an effective heat conductive pathway. In this work, the “lasagna” g‐C3N4/nanofiber cellulose (NFC) thermal conducting membrane‐filler (MF) is first proposed to address these issues. This membrane‐filler is curled to form a cylinder, and then an anisotropic thermally conductive nanocomposite is fabricated by impregnation of PDMS into the cylinder. The g‐C3N4 can arrange along the direction of heat transfer to create an effective phonon transmission pathway. The thermal conductivity not only achieves 1.94 W m−1 K−1 at a low g‐C3N4/NFC MF loading of 9.16 vol% but also exhibits outstanding electrical insulant. Meanwhile, the thermal conductivity of g‐C3N4 is systematically investigated using the nonequilibrium molecule dynamics simulations. This strategy represents a facile, efficient approach to the design of high‐performance nanocomposites with potential application for thermal management materials.
Highly Stable and Ultrafast Hydrogen Gas Sensor Based on 15 nm Nanogaps Switching in a Palladium–Gold Nanoribbons Array
Authors: Pak Yusin , Jeong Yeonggyo , Alaal Naresh , Kim Hyeonghun , Chae Jeonghoon , Min Jung‐Wook , Devi Assa Aravindh Sasikala , Mitra Somak , Lee Da Hoon , Kumaresan Yogeenth , Park Woojin , Kim Tae‐Wook , Roqan Iman S. , Jung Gun‐Young
Published: December 2018

Palladium (Pd) nanogap hydrogen gas (H2) sensors based on the large volume expansion of β phase palladium hydride (β‐PdH) are highly promising, owing to their fast and accurate sensing capability at room temperature in air. However, such sensors do not work well at H2 concentrations below 1%. At such low H2 concentrations, Pd exists as α‐PdH, which has a slow and insufficient volume expansion and cannot completely close nanogaps. Furthermore, the lattice strains induced from the phase transition (α‐PdH → β‐PdH) behavior degrade the stable and repeatable long‐term sensing capability. Here, these issues are resolved by fabricating an array of periodically aligned alloyed palladium–gold nanoribbons (PdAu NRB) with uniform 15 nm nanogaps. The PdAu NRB sensor enables highly stable and ultrafast H2 sensing at the full detection range of H2 concentrations from 0.005% to 10% along with the excellent limit of detection (≈0.0027%), which is sufficiently maintained even after seven months of storage in ambient atmosphere. These breakthrough results will pave the way for developing a practical high‐performance H2 sensor chip in the future hydrogen era.
Electrically Conductive Thin Films Derived from Bulk Graphite and Liquid–Liquid Interface Assembly
Authors: Blair Victoria E. , Celebi Kemal , Müllen Klaus , Vermant Jan
Published: December 2018

Confinement of particles to fluid–fluid interfaces provides a unique interaction environment, allowing the directed assembly of particles using lateral capillary forces. The particle laden interfacial layers can be deposited onto a variety of substrates for the fabrication of thin film coatings, designed to have structural or functional properties resulting from the interface‐specific structures. For the fabrication of electrically conducting films and specifically graphene‐based coatings, interfacial deposition techniques could offer a low cost and environmentally favorable alternative to conventional gas phase production methods, with possibly a broader choice of substrates. In this work liquid‐phase electrochemical exfoliation is used to produce platelets of few‐layer graphene from bulk graphite which are directly introduced to the water–air interface. These interfaces are characterized through compression experiments and interfacial shear rheology to probe the mechanical properties of the resulting monolayer films and identify mechanical percolation. Further, in situ measurements of electrical conductivity are integrated as a direct indication of electrical percolation. This directly verifies sufficient film quality as an important characteristic of the deposition process. Once deposited on a solid substrate, these films retain their electrical conductivity. But the mechanical properties of the films allow for facile production of freestanding microporous graphene membranes.
Imaging Technologies for Biomedical Micro‐ and Nanoswimmers
Authors: Pané Salvador , Puigmartí‐Luis Josep , Bergeles Christos , Chen Xiang‐Zhong , Pellicer Eva , Sort Jordi , Počepcová Vanda , Ferreira Antoine , Nelson Bradley J.
Published: December 2018

The last decade has seen the rapid development of untethered mobile micro‐ and nanorobots able to navigate liquids by means of external power sources or by harvesting chemicals from their surrounding media. These tiny devices hold great promise for applications in the biomedical field including targeted drug delivery, localized diagnostics, microsurgery, and cell stimulation. However, to translate small‐scale robots from the laboratory to the clinic, many challenges remain. A major obstacle is the lack of imaging technologies that will allow for precise tracking of the devices in vivo. Here, the current progress, challenges, and future possibilities in the monitoring and tracking of biomedical micro‐ and nanomachines using established as well as less conventional imaging technologies are reviewed.
Monolithic Integration of Ion‐Selective Organic Electrochemical Transistors with Thin Film Transistors on Flexible Substrates
Authors: Pierre Adrien , Doris Sean E. , Lujan René , Street Robert A.
Published: December 2018

Organic electrochemical transistors (OECTs) are a promising class of devices for chemical and ionic sensing in aqueous media. Compared with conventional potentiometric techniques, OECT ion‐sensors exhibit low output impedance that aids their miniaturization and integration in multi‐sensor systems. However, in order to implement arrays of OECT sensors for multi‐analyte detection or spatial mapping of analytes, it is critical that the sensors be integrated with an addressing system that minimizes the number of signal lines leaving the sensor array. In this work, an integrated system comprising miniaturized ion‐selective OECTs (IS‐OECTs) that are addressed by a simple multiplexing circuit composed of indium gallium zinc oxide (IGZO) thin‐film transistors (TFTs) is reported. The resulting flexible sensor array accepts a set of voltage inputs that selects the currently active sensor, and the active sensor's measured ion concentration is outputted as a single voltage output. This simple readout circuit allows arrays of IS‐OECTs to be monitored with low‐cost electronic equipment, enabling their use in multi‐ion sensing and high‐resolution mapping of ion concentrations in fields ranging from biomedical research to environmental monitoring.
Efficient CsPbBr3 Perovskite Light‐Emitting Diodes Enabled by Synergetic Morphology Control
Authors: Cheng Li‐Peng , Huang Jing‐Sheng , Shen Yang , Li Guo‐Peng , Liu Xiao‐Ke , Li Wei , Wang Yu‐Han , Li Yan‐Qing , Jiang Yang , Gao Feng , Lee Chun‐Sing , Tang Jian‐Xin
Published: December 2018

The development of solution‐processed inorganic metal halide perovskite light‐emitting diodes (PeLEDs) is currently hindered by low emission efficiency due to morphological defects and severe non‐radiative recombination in all‐inorganic perovskite emitters. Herein, bright PeLEDs are demonstrated by synergetic morphology control over cesium lead bromide (CsPbBr3) perovskite films with the combination of two additives. The phenethylammonium bromide additive enables the formation of mixed‐dimensional CsPbBr3 perovskites featuring the reduced grain size (<15 nm) and efficient energy funneling, while the dielectric polyethyleneglycol additive promotes the formation of highly compact and pinhole‐free perovskite films with defect passivation at grain boundaries. Consequently, green PeLEDs achieve a current efficiency of 37.14 cd A−1 and an external quantum efficiency of 13.14% with the maximum brightness up to 45 990 cd m−2 and high color purity. Furthermore, this method can be effectively extended to realize flexible PeLEDs on plastic substrates with a high efficiency of 31.0 cd A−1.
Preparative Asymmetric Synthesis of Canonical and Non‐canonical α‐amino Acids Through Formal Enantioselective Biocatalytic Amination of Carboxylic Acids
Authors: Dennig Alexander , Blaschke Fabio , Gandomkar Somayyeh , Tassano Erika , Nidetzky Bernd
Published: December 2018

Chemical and biocatalytic synthesis of non‐canonical α‐amino acids (ncAAs) from renewable feedstocks and using mild reaction conditions has not efficiently been solved. Here, we show the development of a three‐step, scalable and modular one‐pot biocascade for linear conversion of renewable fatty acids (FAs) into enantiopure l‐α‐amino acids. In module 1, selective α‐hydroxylation of FAs is catalyzed by the P450 peroxygenase P450CLA. By using an automated H2O2 supplementation system, efficient conversion (46 to >99%; TTN>3300) of a broad range of FAs (C6:0 to C16:0) into valuable α‐hydroxy acids (α‐HAs; >90% α‐selective) is shown on preparative scale (up to 2.3 g L−1 isolated product). In module 2, a redox‐neutral hydrogen borrowing cascade (alcohol dehydrogenase/amino acid dehydrogenase) allowed further conversion of α‐HAs into l‐α‐AAs (20 to 99%). Enantiopure l‐α‐AAs (e.e. >99%) including the pharma synthon l‐homo‐phenylalanine can be obtained at product titers of up to 2.5 g L−1. Based on renewables and excellent atom economy, this biocascade is among the shortest and greenest synthetic routes to structurally diverse and industrially relevant ncAAs.

magnified image
1,5,7‐Triazabicyclo[4.4.0]dec‐5‐ene (TBD) Triggered Diastereoselective [3+2] Cycloaddition of Azomethine Imines and Pyrazoleamides
Authors: Volpe Chiara , Meninno Sara , Capobianco Amedeo , Vigliotta Giovanni , Lattanzi Alessandra
Published: December 2018

A practical and mild approach to prepare tetrahydropyrazolo[1,2‐a]‐pyrazole‐1,7‐diones, bearing up to three stereocentres, by reacting ready available N,N′‐cyclic azomethine imines and pyrazoleamides under catalytic loading of commercial 1,5,7‐triazabicyclo[4.4.0]dec‐5‐ene (TBD), has been developed. The products are obtained in good yields and high diastereoselectivity, working at room temperature. Preliminary bioassay showed the products to inhibit growth of Gram‐positive bacteria.

magnified image
Molecular Engineering of Superplasticizers for Metakaolin‐Portland Cement Blends with Hierarchical Machine Learning
Authors: Menon Aditya , Childs Christopher M. , Poczós Barnabás , Washburn Newell R. , Kurtis Kimberly E.
Published: December 2018

Blending metakaolin (MK), a calcined clay, into portland cement (PC) improves resulting concrete material properties, ranging from strength to durability, as well as reducing embodied CO2 and energy. However, superplasticizers developed for PC can be inefficient or ineffective for improving the dispersion of PC‐MK blends. Here, a novel machine algorithm is applied to tailor a superplasticizer to address poor flowability characteristic of 15/85 blends of MK‐PC. A hierarchical machine learning (HML) system is trained on a library of seven superplasticizers using a middle layer, which represents underlying physical interactions that determine system responses, based on polymer contributions to physicochemical forces in both the pore solution and particle surface. Following reparameterization of the response surface by polymer composition, the trained algorithm predicted that a novel styrene sulfonate‐methacrylic acid‐poly(ethylene glycol) methacrylate copolymer would maximize slump of the MK‐PC paste. Synthesis of the algorithm prediction resulted in a water‐soluble polymer with an extremely high intrinsic viscosity that nevertheless increased the slump flow of the MK‐PC paste but did not plasticize pure PC paste. The results from this study demonstrate the importance of HML as a design tool for the molecular engineering of complex material systems.
Over 6% Certified Sb2(S,Se)3 Solar Cells Fabricated via In Situ Hydrothermal Growth and Postselenization
Authors: Wang Weihuang , Wang Xiaomin , Chen Guilin , Yao Liquan , Huang Xiaojuan , Chen Tao , Zhu Changfei , Chen Shuiyuan , Huang Zhigao , Zhang Yi
Published: December 2018

Antimony sulfide‐selenide Sb2(S,Se)3 as a promising absorber material has drawn extensive attention owing to its rewarding photoelectric properties, low toxicity, and earth abundant components. Here, an available and highly effective method, in situ hydrothermal growth accompanied with postselenization, is successfully applied to fabricate Sb2(S,Se)3 solar cells. The rationale for the preparation of Sb2S3 precursors by the hydrothermal method is discussed, and detailed characterization of Sb2(S,Se)3 films selenized with different temperatures is also carried out. Finally, a solar cell with structure of FTO/CdS/Sb2(S,Se)3/Spiro‐OMeTAD/Au is fabricated, which delivers an encouraging 6.14% efficiency with Voc of 732 mV, Jsc of 14.6 mA cm−2, and fill factor of 60.8%. This work provides valuable references for further development and improvement of Sb2(S,Se)3 solar cells.
2D Material‐Based Vertical Double Heterojunction Bipolar Transistors with High Current Amplification
Authors: Lee Geonyeop , Pearton Stephen J. , Ren Fan , Kim Jihyun
Published: December 2018

The heterojunction bipolar transistor (HBT) differs from the classical homojunction bipolar junction transistor in that each emitter‐base‐collector layer is composed of a different semiconductor material. 2D material (2DM)‐based heterojunctions have attracted attention because of their wide range of fundamental physical and electrical properties. Moreover, strain‐free heterostructures formed by van der Waals interaction allows true bandgap engineering regardless of the lattice constant mismatch. These characteristics make it possible to fabricate high‐performance heterojunction devices such as HBTs, which have been difficult to implement in conventional epitaxy. Herein, NPN double HBTs (DHBTs) are constructed from vertically stacked 2DMs (n‐MoS2/p‐WSe2/n‐MoS2) using dry transfer technique. The formation of the two P–N junctions, base‐emitter, and base‐collector junctions, in DHBTs, was experimentally observed. These NPN DHBTs composed of 2DMs showed excellent electrical characteristics with highly amplified current modulation. These results are expected to extend the application field of heterojunction electronic devices based on various 2DMs.
3D Printing of Tunable Energy Storage Devices with Both High Areal and Volumetric Energy Densities
Authors: Gao Tingting , Zhou Zhan , Yu Jianyong , Zhao Jing , Wang Guiling , Cao Dianxue , Ding Bin , Li Yiju
Published: December 2018

Developing advanced supercapacitors with both high areal and volumetric energy densities remains challenging. In this work, self‐supported, compact carbon composite electrodes are designed with tunable thickness using 3D printing technology for high‐energy‐density supercapacitors. The 3D carbon composite electrodes are composed of the closely stacked and aligned active carbon/carbon nanotube/reduced graphene oxide (AC/CNT/rGO) composite filaments. The AC microparticles are uniformly embedded in the wrinkled CNT/rGO conductive networks without using polymer binders, which contributes to the formation of abundant open and hierarchical pores. The 3D‐printed ultrathick AC/CNT/rGO composite electrode (ten layers) features high areal and volumetric mass loadings of 56.9 mg cm−2 and 256.3 mg cm−3, respectively. The symmetric cell assembled with the 3D‐printed thin GO separator and ultrathick AC/CNT/rGO electrodes can possess both high areal and volumetric capacitances of 4.56 F cm−2 and 10.28 F cm−3, respectively. Correspondingly, the assembled ultrathick and compact symmetric cell achieves high areal and volumetric energy densities of 0.63 mWh cm−2 and 1.43 mWh cm−3, respectively. The all‐component extrusion‐based 3D printing offers a promising strategy for the fabrication of multiscale and multidimensional structures of various high‐energy‐density electrochemical energy storage devices.
Tin Intercalated Ultrathin MoO3 Nanoribbons for Advanced Lithium–Sulfur Batteries
Authors: Yang Weiwei , Xiao Jiewen , Ma Yang , Cui Shiqiang , Zhang Peng , Zhai Pengbo , Meng Lingjia , Wang Xingguo , Wei Yi , Du Zhiguo , Li Bixuan , Sun Zhibo , Yang Shubin , Zhang Qianfan , Gong Yongji
Published: December 2018

Heteroatom doping strategies have been widely developed to engineer the conductivity and polarity of 2D materials to improve their performance as the host for sulfur cathode in lithium–sulfur batteries. However, further improvement is limited by the inhomogeneity and the small amount of the doping atoms. An intercalation method to improve the conductivity and polarity of 2D‐layered α‐MoO3 nanoribbons is developed here, thus, resulting in much improved electrochemical performance as sulfur host with better rate and cycle performance. The first principle calculations show that the binding energy of MoO3 and lithium polysulfides, lithium sulfide and sulfur is significantly improved after Sn intercalation. The Sn0.063MoO3‐S cathode delivers an initial specific capacity of 1390.3 mAh g−1 at 0.1 C with the Coulombic efficiency up to 99.7% and shows 79.6% retention of the initial capacity over 500 cycles at 1 C rate with a capacity decay of 0.04% per cycle. This intercalation method provides a new strategy to engineer the electrochemical properties of 2D materials.
Schuurs‐Hoeijmakers syndrome in two patients from Japan
Authors: Hoshino Yusuke , Enokizono Takashi , Imagawa Kazuo , Tanaka Ryuta , Suzuki Hisato , Fukushima Hiroko , Arai Junichi , Sumazaki Ryo , Uehara Tomoko , Takenouchi Toshiki , Kosaki Kenjiro
Published: December 2018

Schuurs‐Hoeijmakers syndrome is a rare disease characterized by intellectual disability and dysmorphic facial features among various physical abnormalities due to PACS1 mutation. To date, 28 patients with a recurrent de novo PACS1 mutation (c.607C > T) have been reported, primarily in Western populations. Here, we describe two Japanese patients with Schuurs‐Hoeijmakers syndrome with a recurrent PACS1 mutation. In addition to the typical clinical symptoms, each patient presented novel clinical phenotypes. One patient presented with involuntary movements and was treated with trihexyphenidyl hydrochloride. We hypothesized that the PACS1 mutation leads to an inherent dopaminergic insufficiency that underlies the developing symptoms along with the neurodevelopmental processes. The second patient was diagnosed with lipomyelomeningocele during an examination for severe constipation at the age of 2 years and 8 months. The diagnosis of lipomyelomeningocele in this patient was delayed due to the lack of cutaneous lesions. As the majority of patients with PACS1 mutation present constipation, underdiagnosis of lipomyelomeningocele is a possibility. As the phenotypic expansion of the patients with Schuurs‐Hoeijmakers syndrome was not fully recognized, additional studies are needed to clarify the clinical spectrum.
Effects of age and body proportions on stature estimation
Authors: Ruff Christopher B. , Niskanen Markku , Maijanen Heli , Mays Simon
Published: December 2018

Objectives

Two issues involved in mathematical estimation of stature from long bone lengths are explored: the use of different age points for estimating maximum adult stature, and the effects of linear body proportions on stature estimation errors. Both issues were raised by a recent analysis of stature in the British Medieval Wharram Percy sample.

Materials and methods

A large (n > 500) sample of European skeletal remains with anatomically estimated statures is used to test associations between relative lower limb length and errors in stature estimation using previously published equations for European samples. Two cadaveric samples of known ages (Terry and Bass Collections) are used to identify the most appropriate age point to employ in a linear equation with an age term for estimation of maximum adult anatomical stature.

Results

Relative lower limb length is positively correlated with errors in stature estimation from lower limb bone lengths. Underestimation of stature in the Wharram Percy sample by the European equations is largely attributable to the relatively short lower limbs of this sample compared to Europeans in general. Two methods for assessing and adjusting for relative lower limb length variation are presented. Maximum adult stature is best estimated using an age point of 30 years when a linear age term is employed.

Discussion

Body proportions may vary even within relatively closely related populations, so should be assessed and compared to those of reference samples whenever possible when applying mathematical stature equations.
Fractal Coding Metamaterials
Authors: Moeini Samaneh , Cui Tie Jun
Published: December 2018

The concept of fractal coding metamaterials is proposed here, which can be used to design reflective metasurfaces with self‐similar pseudo‐random phase responses based on the coding strategy utilizing fractal interpolation functions (FIF). The class of fractals whose FIF is formed by a contraction mapping on the y‐coordinate and an arbitrary linear function of the x‐coordinate is considered. This formulation is used in deriving the theoretical model and in the experimental realization. An analytical relation between the reflection phase distribution in the form of the above‐mentioned FIF and the far‐field radiation pattern of the structure is derived. In the numerical example, a reflecting metasurface formed by slotted metallic patches of varying sizes is considered. A number of full wave scattering simulations for such a metamaterial reflectarray are performed and the optimal designs which make the response of the structure more accurate as compared with the analytical predictions are identified. Following the simulation results, the array is built and a number of measurements are performed. The results of this work may find applications in phased antenna array design and beam forming.
Constraining Exotic Interactions
Authors: Ficek Filip , Budker Dmitry
Published: December 2018

Beyond‐the‐standard‐model interactions mediated by an exchange of virtual “new” bosons result in a finite set of possible effective interaction potentials between standard‐model particles such as electrons and nucleons. The classification of such potentials is discussed and recent experiments searching for such exotic interactions at spatial scales from sub‐nanometers to tens of thousand kilometers are briefly reviewed.
The Planck Constant for the Definition and Realization of the Kilogram
Authors: Wood Barry , Bettin Horst
Published: December 2018

On May 20, 2019 the values of the Planck, h, and Avogadro, NA, constants will be fixed, revising our measurement system, the International System of Units (SI), and providing a new way to get mass traceability. While the famous energy relations mc2 and hf may remind many that the Planck constant is indeed related to mass, it is less recognized how this is also true for the Avogadro constant. These concepts are reviewed in the context of the upcoming revision of the SI. How the fixed values were chosen and how mass traceability will be maintained with the smallest uncertainty are also discussed.
Gasotransmitter Regulation of Phosphatase Activity in Live Cells Studied by Three‐Channel Imaging Correlation
Authors: Ou Pan , Zhang Ruilong , Liu Zhengjie , Tian Xiaohe , Han Guangmei , Liu Bianhua , Hu Zhangjun , Zhang Zhongping
Published: December 2018

Enzyme activity in live cells is dynamically regulated by small‐molecule transmitters for maintaining normal physiological functions. A few probes have been devised to measure intracellular enzyme activities by fluorescent imaging, but the study of the regulation of enzyme activity via gasotransmitters in situ remains a long‐standing challenge. Herein, we report a three‐channel imaging correlation by a single dual‐reactive fluorescent probe to measure the dependence of phosphatase activity on the H2S level in cells. The two sites of the probe reactive to H2S and phosphatase individually produce blue and green fluorescent responses, respectively, and resonance energy transfer can be triggered by their coexistence. Fluorescent analysis based on the three‐channel imaging correlation shows that cells have an ideal level of H2S to promote phosphatase activity up to its maximum. Significantly, a slight deviation from this H2S level leads to a sharp decrease of phosphatase activity. The discovery further strengthens our understanding of the importance of H2S in cellular signaling and in various human diseases.
Kontrolle über Kettenvernetzung und Einzelkettenverknüpfung durch zwei Farben des sichtbaren Lichts
Authors: Frisch Hendrik , Bloesser Fabian R. , Barner‐Kowollik Christopher
Published: December 2018

Während photochemische Synthese den Zugang zu orts‐ und zeitaufgelöster Reaktionskontrolle ermöglicht, ist ihr Potential spezifische Reaktionen mit einer bestimmten Farbe des Lichts auszulösen durch omnipräsente spektrale Überlappe der reaktiven Gruppen limitiert. Nachfolgend wird ein neues Konzept vorgestellt, das aktiv eine von zwei Ligationsreaktionen unterdrückt, indem die Cycloreversion der [2+2]‐Cycloaddition des Styrylpyrens induziert wird. Die Kombination dieser photoreversiblen Chemie und der [4+4]‐Cycloaddition des 9‐Triazolylanthracens ermöglicht es zuerst eine Kettenkupplung unter Verwendung von UV‐Licht zu initiieren und anschließend den daraus hervorgehenden Einzelketten‐Nanopartikel (single chain nanoparticle, SCNP) mit einer zweiten Polymerkette unter Verwendung von blauem Licht zu ligieren. Durch erstmals erreichte sequenzunabhängige λ‐orthogonale Reaktivität konnte dieselbe makromolekulare Architektur in der umgekehrten Bestrahlungssequenz erhalten werden, indem zuerst mit blauem Licht und darauffolgend mit violettem Licht bestrahlt wurde – ohne jegliche Verwendung von harschem UV‐Licht.
Dissoziation schwacher Säuren über den gesamten Molenbruchbereich
Authors: Blasius Jan , Ingenmey Johannes , Perlt Eva , von Domaros Michael , Hollóczki Oldamur , Kirchner Barbara
Published: December 2018

Wir präsentieren am Beispiel von in Wasser gelöster Ameisensäure und Essigsäure, dass der Ansatz der binären Quantum‐Cluster‐Equilibrium‐(bQCE)‐Theorie die Säurestärke über den gesamten Konzentrationsbereich vorhersagen kann. Wir zeigen über einen Molenbruchbereich von 0 bis 0.7, dass die molenbruchabhängige Säurestärke nicht mit simplen Annahmen beschrieben werden kann. Hierin spiegelt sich das komplexe Zusammenspiel verfügbarer dissoziierter Ionen oder konjugierter Basen mit vorhandenen Säure‐ und Wassermolekülen wider. Zusätzlich können unsere berechneten Ionenkonzentrationen das experimentelle Leitfähigkeitsmaximum der Essigsäure mit hervorragender, das der Ameisensäure mit zufriedenstellender Genauigkeit beschreiben. Da für die Ergebnisse nur eine geringe Anzahl an einfachen, quantenchemischen Berechnungen notwendig ist, eignet sich die bQCE‐Theorie als neuer und nützlicher Ansatz, um Eigenschaften nichtwässriger Lösungen vorherzusagen. Die Methode ist außerdem in der Lage, Ionisationsprozesse in hochkonzentrierten Lösungen zu beschreiben, die sowohl für chemische und biologische Systeme wie auch für technologische Prozesse von großer Relevanz sind.
Introducing the Petasis Reaction for Late‐Stage Multicomponent Diversification, Labeling, and Stapling of Peptides
Authors: Ricardo Manuel G. , Llanes Dayma , Wessjohann Ludger A. , Rivera Daniel G.
Published: December 2018

For the first time, the Petasis (borono‐Mannich) reaction is employed for the multicomponent labeling and stapling of peptides. The report includes the solid‐phase derivatization of peptides at the N‐terminus, Lys, and Nϵ‐MeLys side‐chains by an on‐resin Petasis reaction with variation of the carbonyl and boronic acid components. Peptides were simultaneously functionalized with aryl/vinyl substituents bearing fluorescent/affinity tags and oxo components such as dihydroxyacetone, glyceraldehyde, glyoxylic acid, and aldoses, thus encompassing a powerful complexity‐generating approach without changing the charge of the peptides. The multicomponent stapling was conducted in solution by linking Nϵ‐MeLys or Orn side‐chains, positioned at i, i+7 and i, i+4, with aryl tethers, while hydroxy carbonyl moieties were introduced as exocyclic fragments. The good efficiency and diversity oriented character of these methods show prospects for peptide drug discovery and chemical biology.
Controlling Chain Coupling and Single‐Chain Ligation by Two Colours of Visible Light
Authors: Frisch Hendrik , Bloesser Fabian R. , Barner‐Kowollik Christopher
Published: December 2018

While photochemical synthesis offers access to spatiotemporal reaction control, its potential to selectively address specific reactions by the colour of light is usually limited by ubiquitous spectral absorption overlaps of the reactive groups. Herein, a new concept is introduced that actively suppresses one ligation reaction by triggering the cycloreversion of the [2+2] cycloaddition of styrylpyrene. Combination of the photoreversible styrylpyrene chemistry with the [4+4] cycloaddition of 9‐triazolylanthracene makes it possible to initially induce chain coupling using UV light and to subsequently ligate the formed single‐chain nanoparticle (SCNP) with a second polymer chain using blue light. Seizing upon the first sequence‐independent λ‐orthogonal reactivity established here, the same macromolecular architecture was obtained in reverse irradiation sequence, by blue and subsequent violet light irradiation—completely foregoing high‐energy UV light.
Predicting Mole‐Fraction‐Dependent Dissociation for Weak Acids
Authors: Blasius Jan , Ingenmey Johannes , Perlt Eva , von Domaros Michael , Hollóczki Oldamur , Kirchner Barbara
Published: December 2018

We demonstrate for formic and acetic acid dissolved in water as examples that the binary quantum cluster equilibrium (bQCE) approach can predict acid strengths over the whole range of acid concentrations. The acid strength increases in a complex rather than a simple way with increasing mole fraction of the acid from 0 to 0.7, reflecting the complex interplay between the dissociated ions or conjugate bases available as compared to the acid and water molecules. Furthermore, our calculated ion concentrations meet the experimental maximum of the conductivity with excellent agreement for acetic acid and satisfactorily for the formic acid/water mixture. As only a limited number of simple quantum‐chemical calculations are required for the prediction, bQCE is clearly a valuable approach to access these quantities also in non‐aqueous solutions. It is a highly valuable asset for predicting ionization processes in highly concentrated solutions, which are relevant for biological and chemical systems, as well as technological processes.
DNA methyltransferase BmDnmt1 and BmDnmt2 in silkworm (Bombyx mori) and the regulation of silkworm embryonic development
Authors: Li Bing , Hu Pei , Zhang Shang‐Zhi , Toufeeq Shahzad , Wang Jie , Zhao Kang , Xu Xin , Xu Jia‐Ping , Huang Shou‐Jun
Published: December 2018

DNA methylation is one of the most widespread epigenetic marks and has been linked to insect development, especially influencing embryonic development. However, the regulation of DNA methylation in silkworm embryonic development and diapause remain to investigate. In this study, reverse‐transcription quantitative polymerase chain reaction was performed to identify the expression level of Bombyx mori DNA methyltransferases (BmDNMTs) 1 and 2 (
BmDnmt1 and
BmDnmt2) in different tissues, different embryonic developmental stages, and different strains of the silkworm. The results showed that
BmDNMTs were the most highly expressed during embryonic development, especially at early embryonic stages. In particular, the expression of BmDNMTs was significantly upregulated in diapause‐terminated eggs by HCl treatment. Moreover, tissue distribution showed that
BmDnmt2 was highly expressed in testis and ovary, and
BmDnmt1 was highly expressed in testis. This study contributes to understanding the correlation of DNA methylation occurs with embryogenesis and gametogenesis in insect, meanwhile, it provides a research orientation to further analyze the role of DNA methylation in diapause initiation and termination in insect embryonic development.
Purification and characterization of phenoloxidase from the hemolymph of healthy and diseasedAntheraea assamensisHelfer (Lepidoptera: Saturniidae): Effects of certain biological components and chemical agents on enzyme activity
Authors: Baruah Gayatri Sarma , Sarma Hridip Kumar , Bardoloi Sunayan , Bora Dipsikha
Published: December 2018

In the current study, a dimeric phenoloxidase (PO) from the hemolymph of healthy and diseased (pebrine infected) larvae ofAntheraea assamensisHelfer was extracted and purified. The protein was subjected to purification using Sephacryl S‐100 and CM Sepharose chromatography. The enzyme comprised of two subunits of ~76.8 and 76 kDa that showed PO activity in 6 mMl‐3,4‐dihydroxyphenylalanine (L‐DOPA) and 8 mM catechol but not in hydroquinone. Optimum temperature for PO activity was 30°C inl‐DOPA and 37°C in catechol. Optimum pH ranged from 6.8 to 7.0 inL‐DOPA and 7.0–7.2 in catechol. Specific activity of the purified PO from healthy larvae was 53.9 µM/min per mg of protein per ml inL‐DOPA and 50.77 µM/min per mg of protein per ml in catechol. Specific activity of PO from diseased larvae was 30.0 µM/min per mg of protein per ml inL‐DOPA and 28.55 µM/min per mg of protein per ml in catechol. Purification fold was 3.27–4.21 for healthy and 2.38–2.56 for diseased fractions. The enzyme showed the Michaelis constant (Km) of 2.46–2.85 mM for healthy and diseased fractions inL‐DOPA. In catecholKmof 9.23–17.71 mM was observed. Peptidoglycan was the best activator of purified PO from both healthy and diseased fractions. Interactions between controls and activators appeared statistically significant (F = 767.5;df = 3;P < 0.0001). Na+, K+, and Cu2+increased, whereas Ca2+, Zn2+, Mg2+, and Co2+decreased PO activity. The overall interactions appeared highly significant (F = 217.0;df = 27;P < 0.0001). Kojic acid, dithiothreitol, thiourea, phenylthiourea, carbendazim,N‐bromosuccinimide,N,N,N′,N′‐tetraacetic acid, and diethyldithiocarbamate inhibited PO activity.
Light/Palladium‐Promoted Benzylic C−H Acylation Using a Benzoyl Group as the Photo‐Directing Group
Authors: Masuda Yusuke , Ishida Naoki , Murakami Masahiro
Published: December 2018

2‐Methylphenyl ketones undergo site‐selective acylation at the benzylic position when treated with acid anhydride under UV irradiation in the presence of a palladium catalyst. The benzoyl carbonyl group serves as the photo‐directing group so that the ortho benzylic C−H bond is activated site‐selectively.
Cytoprotective, anti‐inflammatory, and antioxidant properties of high‐molecular‐weight hyaluronan enriched with red orange extract in human fibroblasts exposed to ultra violet light B irradiation
Authors: Penna Ilaria , Albanesi Ennio , Bertorelli Rosalia , Bandiera Tiziano , Russo Debora
Published: December 2018

Ultraviolet (UV) light exposure is the primary factor responsible for skin photoaging, affecting all the skin layers, mainly through the production of reactive oxygen species (ROS), activation of inflammatory responses, and apoptosis. In keeping with this evidence, exogenous supplementation with dietary antioxidants has been shown to provide photoprotective benefits. Moreover, oral administration of hyaluronic acid (HA) has been proved to reduce the signs of aged skin, such as wrinkles, and increase hydration and elasticity. The combination of different biologically active substances in order to slow down the onset of skin aging could represent a promising preventive strategy against photoaging. In the present study, we investigated the effects of a dietary supplement (IALUTEC® RED), consisting of high‐molecular‐weight HA (HMW‐HA) combined with red orange extract (ROC‐Red Orange Complex®), in human fibroblasts exposed to ultra violet light B‐induced oxidative stress. Our study suggests that, in fibroblasts exposed to UVB light, IALUTEC® RED is active in decreasing both the inflammatory response and the generation of ROS, two events that are involved in skin photoaging.
Goodness‐of‐fit tests for disorder detection in NGS experiments
Authors: Jiménez‐Otero Norman , de Uña‐Álvarez Jacobo , Pardo‐Fernández Juan Carlos
Published: December 2018

Next‐generation sequencing (NGS) experiments are often performed in biomedical research nowadays, leading to methodological challenges related to the high‐dimensional and complex nature of the recorded data. In this work we review some of the issues that arise in disorder detection from NGS experiments, that is, when the focus is the detection of deletion and duplication disorders for homozygosity and heterozygosity in DNA sequencing. A statistical model to cope with guanine/cytosine bias and phasing and prephasing phenomena at base level is proposed, and a goodness‐of‐fit procedure for disorder detection is derived. The method combines the proper evaluation of localp‐values (one for each DNA base) with suitable corrections for multiple comparisons and the discrete nature of thep‐values. A global test for the detection of disorders in the whole DNA region is proposed too. The performance of the introduced procedures is investigated through simulations. A real data illustration is provided.
Determining Collision Cross‐Sections of Aromatic Compounds in Crude Oil by Using Aromatic Compound Mixture as Calibration Standard
Authors: Lim Dongwan , Davidson Kimberly L. , Son Seungwoo , Ahmed Arif , Bush Matthew F. , Kim Sunghwan
Published: December 2018

Collisional cross section (CCS) values of a set of aromatic compounds were determined and the compounds were evaluated as standards for calibration and standardization. External calibration with poly‐DL‐alanine and internal and external calibration with the aromatic compounds were performed using the ion mobility mass spectra obtained from crude oils. The results showed that the external calibration method using the set of aromatic compounds is both accurate and easy to implement. The improved accuracy obtained using these aromatic standards can be explained by their greater structural similarity with the analytes in the crude oils. We anticipate that the adoption of these standards will increase the utility of IM‐MS in petroleum analysis and make it easier to directly compare results from different studies.
Conceptualizing businesses as social actors: A framework for understanding sustainability actions in small‐ and medium‐sized enterprises
Authors: Westman Linda , Luederitz Christopher , Kundurpi Aravind , Mercado Alexander Julian , Weber Olaf , Burch Sarah Lynne
Published: December 2018

Small‐ and medium‐sized enterprises (SMEs) can play a crucial role in advancing environmental and social well‐being. Yet various—often conflicting—explanations have been offered to clarify why SMEs pursue sustainability. Some arguments foreground possibilities of profit maximization, whereas others emphasize individual values and convictions. Research supporting such contradicting explanations is often biased towards large enterprises or small, innovative frontrunners. In this article, we examine the underlying drivers of social and environmental interventions of SMEs by exploring empirical data from a survey of over 1,600 Canadian SMEs and complementary in‐depth interviews. We argue that sustainability actions of SMEs can be understood by viewing these firms as social actors—organizations that are shaped by individual values, internal and external interpersonal relationships, and are embedded in a social environment. This conceptualization directs attention to the full range of factors that shape sustainability engagement of SMEs and highlights frequently overlooked forms of sustainability‐oriented actions.
Engineering the Mycomembrane of Live Mycobacteria with an Expanded Set of Trehalose Monomycolate Analogues
Authors: Fiolek Taylor J. , Banahene Nicholas , Kavunja Herbert W. , Holmes Nathan J. , Rylski Adrian K. , Pohane Amol Arunrao , Siegrist M. Sloan , Swarts Benjamin M.
Published: December 2018

Mycobacteria and related organisms in the Corynebacterineae suborder are characterized by a distinctive outer membrane referred to as the mycomembrane. Biosynthesis of the mycomembrane occurs through an essential process called mycoloylation, which involves antigen 85 (Ag85)‐catalyzed transfer of mycolic acids from the mycoloyl donor trehalose monomycolate (TMM) to acceptor carbohydrates and, in some organisms, proteins. We recently described an alkyne‐modified TMM analogue (O‐AlkTMM‐C7) which, in conjunction with click chemistry, acted as a chemical reporter for mycoloylation in intact cells and allowed metabolic labeling of mycoloylated components of the mycomembrane. Here, we describe the synthesis and evaluation of a toolbox of TMM‐based reporters bearing alkyne, azide, trans‐cyclooctene, and fluorescent tags. These compounds gave further insight into the substrate tolerance of mycoloyltransferases (e.g., Ag85s) in a cellular context and they provide significantly expanded experimental versatility by allowing one‐ or two‐step cell labeling, live cell labeling, and rapid cell labeling via tetrazine ligation. Such capabilities will facilitate research on mycomembrane composition, biosynthesis, and dynamics. Moreover, because TMM is exclusively metabolized by Corynebacterineae, the described probes may be valuable for the specific detection and cell‐surface engineering of Mycobacterium tuberculosis and related pathogens. We also performed experiments to establish the dependence of probe incorporation on mycoloyltransferase activity, results from which suggested that cellular labeling is a function not only of metabolic incorporation (and likely removal) pathway(s), but also accessibility across the envelope. Thus, whole‐cell labeling experiments with TMM reporters should be carefully designed and interpreted when envelope permeability may be compromised. On the other hand, this property of TMM reporters can potentially be exploited as a convenient way to probe changes in envelope integrity and permeability, facilitating drug development studies.
Breaking the Fourth Wall: Modulating Quaternary Associations for Protein Regulation and Drug Discovery
Authors: Long Marcus J. C. , Hnedzko Dziyana , Kim Bo Kyoung , Aye Yimon
Published: December 2018

Protein–protein interactions (PPIs) are an effective means to orchestrate intricate biological processes required to sustain life. Approximately 650 000 PPIs underlie the human interactome; thus underscoring its complexity and the manifold signaling outputs altered in response to changes in specific PPIs. This minireview illustrates the growing arsenal of PPI assemblies and offers insights into how these varied PPI regulatory modalities are relevant to customized drug discovery, with a focus on cancer. First, known and emerging PPIs and PPI‐targeted drugs of both natural and synthetic origin are categorized. Building on these discussions, the merits of PPI‐guided therapeutics over traditional drug design are discussed. Finally, a compare‐and‐contrast section for different PPI blockers, with gain‐of‐function PPI interventions, such as PROTACS, is provided.