bluuebunny/crossref_metadata_2025 huggingface dataset:
An Ir/Ni(OH)2 Heterostructured Electrocatalyst for the Oxygen Evolution Reaction: Breaking the Scaling Relation, Stabilizing Iridium(V), and Beyond
Authors: Zhao Guoqiang , Li Peng , Cheng Ningyan , Dou Shi Xue , Sun Wenping
Published: May 2020

Developing efficient electrocatalysts for the oxygen evolution reaction (OER) is highly challenging for hydrogen production from water splitting, due to the high energy barrier for OO bond formation and the restriction of the scaling relation between the multiple reaction intermediates. In order to simultaneously address these concerns, an Ir/Ni(OH)2 heterostructure with abundant heterointerfaces is deliberately designed as an efficient electrocatalyst system, with Ir nanoparticles (NPs) homogeneously confined on the Ni(OH)2 nanosheets. The strong electronic interaction and chemical bonding across the interface between the Ir and Ni(OH)2 can effectively stabilize the metastable electrophilic Ir(V) species, which is vital to boost the formation of OO bonds. Meanwhile, the adsorption of the multiple intermediates is synergistically optimized at the heterointerface, which breaks the restrictive scaling relation and substantially accelerates the OER kinetics. In addition, the severe agglomeration of Ir species is greatly mitigated by the confinement effect, ensuring the structural integrity of the catalyst and the constant exposure of active sites. Owing to its well‐defined multifunctional interfaces, the Ir/Ni(OH)2 heterostructure exhibits exceptional OER activity and durability in alkaline media. The present results highlight the significance of heterostructure interface engineering toward the rational design and development of advanced electrocatalysts for the OER and beyond.
Sustainable Fuel Production from Ambient Moisture via Ferroelectrically Driven MoS2 Nanosheets
Authors: Yang Lin , Loh Leyi , Nandakumar Dilip Krishna , Lu Wanheng , Gao Mengqi , Wee Xue Le Charlotte , Zeng Kaiyang , Bosman Michel , Tan Swee Ching
Published: May 2020

Unlike traditional water splitting in an aqueous medium, direct decomposition of atmospheric water is a promising way to simultaneously dehumidify the living space and generate power. Here, a tailored superhygroscopic hydrogel, a catalyst, and a solar cell are integrated into a humidity digester that can break down ambient moisture into hydrogen and oxygen, creating an efficient electrochemical cell. The function of the hydrogel is to harvest moisture from ambient humidity and transfer the collected water to the catalyst. Barium titanate and vertical 2D MoS2 nanosheets are integrated as the catalyst: the negatively polarized cathode can enhance the electron transport and attract H+ to the MoS2 surface for water reduction, while water oxidation takes place at the positively polarized anode. By employing this mechanism, it is possible to maintain the relative humidity in a medium‐sized room at <60% without any additional energy input, and a stable current of 12.5 mA cm−2 is generated by the humidity digester when exposed to ambient light.
The Design of Hydrophilic Nanochannel‐Macrostripe Fog Collector: Enabling Wicking‐Assisted Vertical Liquid Delivery for the Enhancement in Fog Collection Efficiency
Authors: Lee Jonggyu , So Jinyoung , Bae Won‐Gyu , Won Yoonjin
Published: May 2020

The design of water collectors that capture atmospheric fogs has been challenging due to the reliability issue. In particular, the small openings of collecting surfaces are often clogged by large‐size droplets. The additional hydraulic resistances added to the collecting surfaces prevent the fog pathways and further lower the overall performance coefficients by decreasing the shade coefficient of the collectors. The clogging issues can be addressed by modulating the fog harvesters' surface chemistry and surface structures to deliver water droplets efficiently and to prevent re‐entrainment of droplets to the openings. Herein, the novel design of fog collectors that consist of both nanochannels and macrostripes is demonstrated. The combination of those two structures provides the anisotropic wettability and thereby directional spreading in the longitudinal direction to the nanochannels. The directional liquid spreading facilitates continuous liquid transport through the formation of a thin liquid film. As a result, the fog collector successfully enhances the fog harvesting performance by 50% compared to conventional mesh‐like fog collectors.
An Emulsion Approach to Resolve the Paradox of 3D Printing of Very Soft Silicones
Authors: Perrinet Clément , Courtial Edwin‐Joffrey , Colly Arthur , Marquette Christophe , Fulchiron René
Published: May 2020

3D printing of silicone has been a challenge for medical applications for several years. The main property of medical silicone (mostly polydimethylsiloxane) is its mechanical similitude with human tissues. The very soft tissues as prostate, skin, liver, etc, are of Young's modulus lower than 100 kPa. 3D printing for such soft materials is not as obvious as printing thermoplastic polymers. In this work, the goal is to elaborate formulations of room‐temperature‐vulcanizing (RTV) silicone leading to final materials of Young's modulus down to 25 kPa while being processable by liquid deposition modeling, a layer by layer deposit of extruded filament. The main challenge is keeping the material with a sufficient firmness during the process to maintain the shape of the object but without increasing its final rigidity. Therefore, a RTV silicone is mixed with a hydrophilic liquid to create an emulsion of high yield stress behavior. Different emulsions are tested to optimize the composition on the basis of rheological measurements carried out to determine the yield stress variation and compare it to an emulsion model. Then, after printing and curing, the hydrophilic liquid is removed to create a material of fine porosity and consequently of low Young's modulus.
Pulsed Laser Photopatterning of Cesium Lead Halide Perovskite Structures as Robust Solution‐Processed Optical Gain Media
Authors: Tan Max J. H. , Chan Yinthai
Published: May 2020

Solution‐processed optical gain media such as thin films of colloidal semiconductor nanocrystals promise ease of fabrication and scalable production while offering a spectrally wide range of emission colors. However, depositing such gain media in a size‐ and shape‐specific manner at a precise location on a substrate can be highly challenging. In this work, a facile approach for fabricating solution‐processed cesium lead halide perovskite structures of any arbitrary shape and size from their nanocrystal counterparts via a pulsed laser photopatterning process is demonstrated. The photopatterned structures resist solvation in both polar and nonpolar solvents, allowing for the straightforward removal of unpatterned regions. Their robustness is attributed to the ligand‐removal, sintering, and photoannealing of the nanocrystals at the site of irradiation. Concomittantly, the photopatterning process results in lengthened Auger‐dominated biexciton lifetimes and larger absorption cross‐sections that permit relatively low amplified spontaneous emission thresholds. It is shown that the photopatterning process may be used to fabricate cesium lead halide based gain media capable of multiwavelength emission, orientation‐dependent wavelength of emission, as well as functional operation while fully immersed in various solvents. It is envisioned that the photopatterning process may be extended to other perovskite systems to include applications beyond those requiring light‐emission.
A Novel Bridge‐Ring Phosphine Oxide Host 5,10‐[1,2]Benzenophosphanthrene 5,10‐Dioxide for Ultralow‐Voltage‐Driven Blue Thermally Activated Delayed Fluorescence Diodes
Authors: Gao Feifei , Du Ruiming , Jiao Fuxing , Lu Guang , Zhang Jing , Han Chunmaio , Xu Hui
Published: May 2020

The molecular configuration optimization is crucial for accurately controlling the intermolecular interactions of organic conjugates. Herein, with the purpose to integrate spherical geometry and optoelectronic properties, the first phosphine oxide (PO) bridge‐ring host 5,10‐[1,2]benzenophosphanthrene 5,10‐dioxide (BPAO2) with phosphorus as bridgehead atom is demonstrated. The sphere‐like paddle‐wheel configuration of BPAO2 gives rise to the highly ordered layer‐by‐layer packing mode, owing to its single molecular orientation, which provides the weak π–π interactions in each layer and hydrogen bond networks between layers. These limited but sufficient interactions are preserved in dilute solution and vacuum‐evaporated film, balancing the charge transportation and the quenching suppression. As consequence, its blue thermally activated delayed fluorescence (TADF) diodes achieve the record‐low turn‐on voltage as 2.3 V, which is remarkably below blue photon energy (≈2.6 eV), and the power efficiency up to ≈70 lm W−1. This work demonstrates the great potential of hetero bridge‐ring systems for optoelectronic applications.
Crystalline Hydrogen‐Bonded Organic Chains Achieving Ultralong Phosphorescence via Triplet–Triplet Energy Transfer
Authors: Liu Bai‐Tong , Liu En‐Ping , Sa Rong‐Jian , Liu Tian‐Fu
Published: May 2020

Ultralong organic phosphorescent (UOP) materials without any metal species have broad application prospects in optical technologies and biological imaging due to the low cost and biocompatibility. However, it is still a challenge to prepare new UOP materials with long luminous life and high photoluminescence quantum yield (PLQY). Herein, two organic molecules, 1,4‐phenylenebisboronic acid (PBA) with high PLQY and isophthalic acid (IPA) with long lifetime, are orderly combined into two crystalline hydrogen‐bonded organic chains, named as PBA‐IPA1 and PBA‐IPA2, through supramolecular self‐assembly. Compared with PBA‐IPA1, PBA‐IPA2 shows much improved phosphorescent lifetime (1.59 s) and PLQY (15.72%) due to the triplet–triplet energy transfer between two components, which is further confirmed by computational studies. The obtained material can be potentially used in such areas as information encryption and fingerprint identification, providing a new strategy for design of UOP materials for practical applications.
First Exploration on Electrochemical Activation of Low‐Cost Albite Mineral for Boosting Lithium Storage Capability
Authors: Mei Jun , Wang Tiantian , Peng Hong , Ayoko Godwin A. , Liu Jianjun , Liao Ting , Sun Ziqi
Published: May 2020

The direct use of natural minerals for low‐cost energy storage is a promising solution toward large‐scale and affordable sustainable energy supply, but it is usually impeded by their inert electrochemical activity. In this work, electrochemically inert albite mineral layered particles are activated as a promising low‐cost anode material for electrochemical Li+ ion storage devices through a facile thermal reduction treatment technology. Via this strategy, partial SiO2 reduction within the albite mineral particles and a conductive carbon layer on the surface are simultaneously realized, which effectively addresses the issues of inactive lithium storage and poor electric conductivity of albite minerals. Via theoretical density functional theory calculations and molecular dynamics simulations, the activation mechanism of lithium storage achieved by silica reduction is understood. This innovatively activated albite mineral delivers a maximum specific capacity of >250 mAh g−1 based on a dominant surface‐driven capacitive storage mechanism, and demonstrates excellent capacity and cycling stability at high charging/discharging rates. This design opens a new pathway to address the current cost issue in energy devices, provides insights into producing cost‐effective anodes by using silica‐rich minerals, and gives an alternative solution for improving the chemical reactivity of inorganic natural minerals toward low‐cost and large‐scale energy storages.
Photoemission Spectroscopy Characterization of Halide Perovskites
Authors: Béchu Solène , Ralaiarisoa Maryline , Etcheberry Arnaud , Schulz Philip
Published: May 2020

Controlling the surface and interface properties of halide perovskites (HaPs) materials is key to improve performance and stability of HaP‐based optoelectronic devices such as solar cells. Here, an overview is given on the use of different photoemission spectroscopy (PES) techniques as a tool kit to investigate chemical and electronic properties of surfaces and interfaces in research on HaP compounds. The primary focus of the article is X‐ray photoelectron spectroscopy (XPS), hard X‐ray photoemission spectroscopy (HAXPES), ultraviolet photoemission spectroscopy (UPS), and inverse photoemission spectroscopy (IPES), highlighting the importance of good practices during PES measurements. Starting from the working principles of PES, critical measurement conditions are discussed. In particular, the exposure of the HaP surface to vacuum and high energy radiation can cause accelerated ageing, degradation, and also ionic migration in the sample. The impact of these changes on the electronic and chemical properties is discussed, followed by an analysis of the specific challenges encountered when performing PES measurements of HaPs. These include the deviation from pristine surface conditions, determination of “soft” band edges, and assessment of band bending. The review concludes by emphasizing good practices for PES measurements of HaP samples and outlining the scope of operando type measurements to capture the transient behavior of HaPs in the experiment.
Monolithic Perovskite Tandem Solar Cells: A Review of the Present Status and Advanced Characterization Methods Toward 30% Efficiency
Authors: Jošt Marko , Kegelmann Lukas , Korte Lars , Albrecht Steve
Published: May 2020

Tandem solar cells are the next step in the photovoltaic (PV) evolution due to their higher power conversion efficiency (PCE) potential than currently dominating, but inherently limited, single‐junction solar cells. With the emergence of metal halide perovskite absorber materials, the fabrication of highly efficient tandem solar cells, at a reasonable cost, can significantly impact the future PV landscape. The perovskite‐based tandem solar cells have already shown that they can convert light more efficiently than their standalone sub‐cells. However, to reach PCEs over 30%, several challenges have to be overcome and the understanding of this fascinating technology has to be broadened. In this review, the main scientific and engineering challenges in the field are presented, alongside a discussion of the current status of three main perovskite tandem technologies: perovskite/silicon, perovskite/CIGS, and perovskite/perovskite tandem solar cells. A summary of the advanced structural, electrical, optical, radiative, and electronic characterization methods as well as simulations being utilized for perovskite‐based tandem solar cells is presented. The main findings are summarized and the strength of the techniques to overcome the challenges and gain deeper knowledge for further performance improvement is assessed. Finally, the PCE potential in different experimental and theoretical limits is compared with an aim to shed light on the path towards overcoming the 30% efficiency threshold for all of the three herein reviewed tandem technologies.
Femtosecond Laser‐Etched MXene Microsupercapacitors with Double‐Side Configuration via Arbitrary On‐ and Through‐Substrate Connections
Authors: Li Qiang , Wang Qizhao , Li Linlin , Yang Lijun , Wang Yang , Wang Xiaohui , Fang Hai‐Tao
Published: May 2020

The capacitance of microsupercapacitors (MSCs) can double if both sides of substrates are used to construct MSCs. Nevertheless, achieving electric connections of MSCs through substrates is a challenge due to the difficulty in precisely positioning each MSC couple that has two of the same MSCs units on two sides. In this work, taking advantage of the synchronous etching on both sides of transparent polyethylene terephthalate substrates by femtosecond laser pulses, a double‐sided configuration is attained with high precision in the alignment of back‐to‐back MSC couples and versatile double‐side MSCs are realized via arbitrary on‐ and through‐substrate connections of MXene MSC units. The MXene double‐side MSC fabricated by the series connection of 12 spiral pattern MXene MSC units with interdigital electrodes of 10 μm width interspace can output a large working voltage of 7.2 V. Additionally, femtosecond laser etching brings the transformation of MXene into titania near‐etched edges with a lateral distance less than 1 µm. Such a small laser‐affected area has little influence on the capacitive performance, which is one of advantages for femtosecond laser over conventional lasers. This research is valuable for one‐step manufacturing of highly integrated MSCs in the field of miniaturized energy storage systems.
Fluorinating π‐Extended Molecular Acceptors Yields Highly Connected Crystal Structures and Low Reorganization Energies for Efficient Solar Cells
Authors: Swick Steven M. , Alzola Joaquin M. , Sangwan Vinod K. , Amsterdam Samuel H. , Zhu Weigang , Jones Leighton O. , Powers‐Riggs Natalia , Facchetti Antonio , Kohlstedt Kevin L. , Schatz George C. , Hersam Mark C. , Wasielewski Michael R. , Marks Tobin J.
Published: May 2020

The synthesis and characterization of new semiconducting materials is essential for developing high‐efficiency organic solar cells. Here, the synthesis, physiochemical properties, thin film morphology, and photovoltaic response of ITN‐F4 and ITzN‐F4, the first indacenodithienothiophene nonfullerene acceptors that combine π‐extension and fluorination, are reported. The neat acceptors and bulk‐heterojunction blend films with fluorinated donor polymer poly{[4,8‐bis[5‐(2‐ethylhexyl)‐4‐fluoro‐2‐thienyl]benzo[1,2‐b:4,5‐b′]‐dithiophene‐2,6‐diyl]‐alt‐[2,5‐thiophenediyl[5,7‐bis(2‐ethylhexyl)‐4,8‐dioxo‐4H,8H‐benzo[1,2‐c:4,5‐c′]dithiophene‐1,3‐diyl]]} (PBDB‐TF, also known as PM6) are investigated using a battery of techniques, including single crystal X‐ray diffraction, fs transient absorption spectroscopy (fsTA), photovoltaic response, space‐charge‐limited current transport, impedance spectroscopy, grazing incidence wide angle X‐ray scattering, and density functional theory level computation. ITN‐F4 and ITzN‐F4 are found to provide power conversion efficiencies greater and internal reorganization energies less than their non‐π‐extended and nonfluorinated counterparts when paired with PBDB‐TF. Additionally, ITN‐F4 and ITzN‐F4 exhibit favorable bulk‐heterojunction relevant single crystal packing architectures. fsTA reveals that both ITN‐F4 and ITzN‐F4 undergo ultrafast hole transfer (<300 fs) in films with PBDB‐TF, despite excimer state formation in both the neat and blend films. Taken together and in comparison to related structures, these results demonstrate that combined fluorination and π‐extension synergistically promote crystallographic π‐face‐to‐face packing, increase crystallinity, reduce internal reorganization energies, increase interplanar π–π electronic coupling, and increase power conversion efficiency.
Rationally Designed Dual‐Mode Triboelectric Nanogenerator for Harvesting Mechanical Energy by Both Electrostatic Induction and Dielectric Breakdown Effects
Authors: Zhou Linglin , Liu Di , Li Shaoxin , Zhao Zhihao , Zhang Chunlei , Yin Xin , Liu Li , Cui Shengnan , Wang Zhong Lin , Wang Jie
Published: May 2020

With the advantages of its light weight, low cost, and high efficiency especially at low operation frequency, the triboelectric nanogenerator (TENG) is considered to be a potential solution for self‐powered sensor networks and large‐scale renewable blue energy. However, the conventional TENG converts mechanical energy into electrical energy only via either electrostatic induction or electrostatic breakdown. Here, a novel dual‐mode TENG is presented, which can simultaneously harvest mechanical energy by electrostatic induction and dielectric breakdown in a single device. Based on the complementary working mechanism, it achieves a great improvement in the output performance with the sum of two TENGs via a single mechanism and reveals the effect of dielectric layer thickness on the triboelectrification, electrostatic induction, and air breakdown. This study establishes a new methodology to optimize TENGs and provides a new tool to investigate the triboelectrification, electrostatic induction and dielectric breakdown simultaneously.
Are Farmers Made Whole by Trade Aid?
Authors: Janzen Joseph P. , Hendricks Nathan P.
Published: May 2020

The USDA provided roughly $23.5 billion in Market Facilitation Program payments to compensate farmers for market losses due to retaliatory tariffs imposed by China and other countries. We examine the distribution of these payments across crops, farms, and regions. Payment rates are larger than estimated price impacts of retaliatory tariffs for most commodities—the difference is especially large for cotton and sorghum. Payment rates relative to farmland cash rent or on a per‐farm basis are greatest in the South. While payments exceed the tariff‐related price impact in the short run, the program may not compensate for long‐run losses due to the trade conflict.
Herbage responses and nitrogen agronomic efficiency of bahiagrass–legume mixtures
Authors: Santos Erick R. S. , Dubeux Jose C. B. , Jaramillo David M. , Garcia Liza , Mackowiak Cheryl L. , Blount Ann R. S. , Pereira‐Neto Jose D. , Queiroz Luana M. D. , Ruiz‐Moreno Martin
Published: May 2020

Bahiagrass (Paspalum notatum Flüggé) is the most utilized forage in Florida and requires N fertilization to optimize production. Integrating legumes into bahiagrass pastures may reduce N fertilizer inputs and improve forage nutritive value. This 2‐yr, 2‐location, on‐farm study established two legumes, alfalfa (Medicago sativa L.) or rhizoma peanut (RP; Arachis glabrata Benth.), in mixtures with bahiagrass. We compared bahiagrass–legume mixtures + 45 kg N ha−1 harvest−1 with their non‐N fertilized monocultures and with bahiagrass + 90 kg N ha−1 harvest−1 (N‐fertilized bahiagrass). Treatments were bahiagrass, N‐fertilized bahiagrass, bahiagrass–alfalfa, bahiagrass–RP, alfalfa, and RP. Variables analyzed included herbage accumulation (HA), botanical composition, forage N concentration, forage total N aboveground (TNAG), and N agronomic efficiency. Mixtures and N‐fertilized bahiagrass resulted in similar cumulative HA (10,400 kg dry matter [DM] ha−1 yr−1, on average) and they were greater than all other treatments (4,190 kg DM ha−1 yr−1, on average). Alfalfa and RP represented low proportions of the mixed swards, with alfalfa proportion being as high as 16.1% and as low as 1.6%. Rhizoma peanut greatest proportion was 2.1% and the lowest was 0.5%. Mixtures and N‐fertilized bahiagrass maintained similar N concentrations, but they were consistently lower than legume monocultures. The N‐fertilized bahiagrass and mixture treatments resulted in the greatest TNAG in four out of the six sampling dates. The AEN of mixtures was typically greater than N‐fertilized bahiagrass. Since legumes had low proportion in mixtures, 45 kg N ha−1 harvest−1 was the upper limit for reaching maximum HA in bahiagrass.
Site‐Selective Trifluoromethylation Reactions of Oligopeptides
Authors: Guerrero Itziar , Correa Arkaitz
Published: May 2020

Site‐selective chemical modifications that target proteinogenic amino acid residues complement the methods entailing genetic manipulation, thereby allowing straightforward and rapid access to engineered proteins. The incorporation of the trifluoromethyl group into amino acids within a peptide sequence results in relevant peptidomimetics with unique biomedicinal properties. As a result, the last decade has witnessed the development of a powerful set of protocols toward the selective trifluoromethylation of small‐to‐medium size peptides and proteins in a late‐stage fashion. This minireview seeks to highlight those particularly compelling cases published in the last years.
Use of high‐fidelity 3‐dimensional–printed models for training novice residents in basic nasal endoscopic skills
Authors: Dong Dong , Liu Wentao , Wu Shuangxia , Cai Fangyu , Wang Yue , Lyu Lei , Zhao Yulin , Zhang Yanbing
Published: May 2020

Background

The use of 3‐dimensional (3D)–printed models is promising in nasal endoscopic technique training. Here, we aimed to develop postsurgical simulants for use in conjunction with 3D‐printed nasal models and to assess their usefulness in helping residents transfer basic endoscopic skills acquired during simulation training to clinical situations.

Methods

The secretion simulant was prepared via a crosslinked reaction between sodium alginate and acrylamide, whereas the packing simulant was prepared using a superabsorbent polymer. After the simulants’ fidelity and utility were evaluated by 5 rhinologists using a 5‐point Likert scale, 46 novice residents were trained using the 3D‐printed nasal models and postsurgical simulants for 2 weeks. A checklist and Global Rating Scale (GRS) were used to assess their performances before and after training, and the time to finish each task was also recorded. Following training, the qualified trainees operated on real patients and were reevaluated.

Results

The simulants’ similarity and usefulness scored ≥4.0, and the training cost was 28 CNY ($4 USD) per session. Following training, the checklist and GRS scores increased, and the operation time decreased (all p < 0.05). There were no statistical differences between the trainees’ performances on the models with the simulants and on patients (all p > 0.05).

Conclusion

The low‐cost simulated secretion and dressing are safe to use. The application of the simulants in conjunction with that of 3D‐printed nasal models in a simulated task setting can help residents in transferring endoscopic skills acquired during simulation teaching to real patients.
A Conjugate Addition Approach to Diazo‐Containing Scaffolds with β Quaternary Centers
Authors: Fang Jian , Howard Evan M. , Brewer Matthias
Published: May 2020

Structurally complex diazo‐containing scaffolds are formed by conjugate addition to vinyl diazonium salts. The electrophile, a little studied α‐diazonium‐α,β‐unsaturated carbonyl compound, is formed at low temperature under mild conditions by treating β‐hydroxy‐α‐diazo carbonyls with Sc(OTf)3. Conjugate addition occurs selectively at the 3‐position of indole to give α‐diazo‐β‐indole carbonyls, and enoxy silanes react to give 2‐diazo‐1,4‐dicarbonyl products. These reactions result in the formation of tertiary and quaternary centers, and give products that would be otherwise difficult to form. Importantly, the diazo functional group is retained within the molecule for future manipulation. Treating an α‐diazo ester indole addition product with Rh2(OAc)4 caused a rearrangement to occur to give a 2‐(1H‐indol‐3‐yl)‐2‐enoate. In the case of diazo ketone compounds, this shift occurred spontaneously on prolonged exposure to the Lewis acidic reaction conditions.
Facile synthesis, characterization, and ab‐initio DFT simulations of energy efficient NN′ dialkyl 1,4 benzene dicarboxamide monomers recovered from PET bottle waste
Authors: Teotia Meenu , Chauhan Mohit , Khan Aamir , Soni Rakesh K.
Published: May 2020

Aminolytic chemical recycling is performed for obtaining NN′ diethyl 1,4 benzene dicarboxamide, NN′ dibutyl 1,4 benzene dicarboxamide, and NN′ dihexyl 1,4 benzene dicarboxamide from Polyethylene terephthalate bottle waste. The compounds were characterized through Fourier transform Infrared spectroscopy, Raman spectroscopy, UV–Visible spectroscopy, 1H NMR, 13C NMR, mass spectrometry, and elemental analysis. Thermal properties were also analyzed with the help of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Density Functional Theory (DFT) study has been performed at GGA‐BLYP (Becke's and Lee–Yang–Parr) functional using SZ basis set to investigate the vibrational frequencies and physical parameters. Experimental vibrational frequencies were found in good accord with the experimental values. Calorific values of the products have been determined using bomb calorimeter as per standard ASTM D240. The values have been correlated with increment of methylene units from NN′ diethyl BdCA to NN′ dihexyl BdCA using standard molar enthalpies of carbon and hydrogen. SEM and EDX analysis of the char residues after combustion has also been carried out to insight the effect of N‐alkyl chain length on calorific values. The calorific values of the recovered compounds are comparable to commercial solid fuels and the compounds may find potential applications in aerospace industry.
Spatially Resolved Transcriptomes—Next Generation Tools for Tissue Exploration
Authors: Asp Michaela , Bergenstråhle Joseph , Lundeberg Joakim
Published: May 2020

Recent advances in spatially resolved transcriptomics have greatly expanded the knowledge of complex multicellular biological systems. The field has quickly expanded in recent years, and several new technologies have been developed that all aim to combine gene expression data with spatial information. The vast array of methodologies displays fundamental differences in their approach to obtain this information, and thus, demonstrate method‐specific advantages and shortcomings. While the field is moving forward at a rapid pace, there are still multiple challenges presented to be addressed, including sensitivity, labor extensiveness, tissue‐type dependence, and limited capacity to obtain detailed single‐cell information. No single method can currently address all these key parameters. In this review, available spatial transcriptomics methods are described and their applications as well as their strengths and weaknesses are discussed. Future developments are explored and where the field is heading to is deliberated upon.
Safe management of surgical smoke in the age of COVID-19
Authors: Mowbray N G , Ansell J , Horwood J , Cornish J , Rizkallah P , Parker A , Wall P , Spinelli A , Torkington J
Published: May 2020

Background

The COVID-19 global pandemic has resulted in a plethora of guidance and opinion from surgical societies. A controversial area concerns the safety of surgically created smoke and the perceived potential higher risk in laparoscopic surgery.

Methods

The limited published evidence was analysed in combination with expert opinion. A review was undertaken of the novel coronavirus with regards to its hazards within surgical smoke and the procedures that could mitigate the potential risks to healthcare staff.

Results

Using existing knowledge of surgical smoke, a theoretical risk of virus transmission exists. Best practice should consider the operating room set-up, patient movement and operating theatre equipment when producing a COVID-19 operating protocol. The choice of energy device can affect the smoke produced, and surgeons should manage the pneumoperitoneum meticulously during laparoscopic surgery. Devices to remove surgical smoke, including extractors, filters and non-filter devices, are discussed in detail.

Conclusion

There is not enough evidence to quantify the risks of COVID-19 transmission in surgical smoke. However, steps can be undertaken to manage the potential hazards. The advantages of minimally invasive surgery may not need to be sacrificed in the current crisis.
The effect of pressure on the characteristics of supercritical carbon dioxide extracts from Calamintha nepeta subsp. nepeta
Authors: Debbabi Haïfa , El Mokni Ridha , Majdoub Siwar , Aliev Aslan , Hammami Saoussen
Published: May 2020

Chemists and industrialists are continuously attempting to develop greener and more environmentally benign chemical processes to extract essential oils and bioactive metabolites of high purity, finding various applications in cosmetics, detergents, nutraceuticals and pharmaceuticals. An increase preferenced for natural products over synthetic ones has made supercritical fluid technology a primary alternative for the generation of high‐value bioactive ingredients. This effective technique requires only moderate temperatures, eliminates clean‐up steps and avoids the use of harmful organic solvents. In this context, our study was focused on the chemical analysis of Calamintha nepeta subsp. nepeta aromatic extracts obtained with supercritical carbon dioxide. The effect of different operating conditions on the capacity of the lipophilic solvent to extract the targeted volatile components was also studied. The process was carried out at a fairly low constant temperature of 40°C, and with varying the pressure from 90 to 300 bar. The chemical composition of the extracts was analyzed by gas chromatography–mass spectroscopy. The results showed that the composition pattern, the concentrations of individual components and the quality of the extractable analytes were affected by pressure increase. The extraction yields varied from 0.73 to 1.21 wt% at 90 and 300 bar, respectively.
Helicobacter pylori‐related risk predictors of gastric cancer: The latest models, challenges, and future prospects
Authors: Bakhti Seyedeh Zahra , Latifi‐Navid Saeid , Safaralizadeh Reza
Published: May 2020

Helicobacter pylori is known as an important determinant of preneoplastic lesions or gastric cancer (GC) risk. The bacterial genotypes may determine the clinical outcomes. However, the evidence for these associations has varied between and within continents, and the actual effect of each gene and corresponding allelic variants are still debatable. In recent years, two new models have been proposed to predict the risk of GC; the phylogeographic origin of H. pylori strains and a disrupted co‐evolution between H. pylori and its human host, which potentially explain the geographic differences in the risk of H. pylori‐related cancer. However, these models and earlier ones based on putative virulence factors of the bacterium may not fully justify differences in the incidence of GC, reflecting that new theories should be developed and examined. Notably, the new findings also support the role of ancestry‐specific germline alteration in contributing to the ethnic/population differences in cancer risk. Moreover the high and low incidence areas of GC have shown differences in transmission ecology, largely affecting the composition of H. pylori populations. As a new hypothesis, it is proposed that any high‐risk population may have its own specific risk loci (or variants) as well as new H. pylori strains with national/maybe regional gene pools that should be considered. The latter is seen in the Americas where the rapid evolution of distinct H. pylori subpopulations has been occurred. It is therefore proposed that the deep sequencing of both H. pylori and its human host is simultaneously performed in GC patients and age‐sex‐matched controls from high‐risk areas. The expression and functional activities of the identified new determinants of GC must then be assessed and matched with human and pathogen ancestry, because some of risk loci are ancestry‐specific. In addition, potential study‐level covariates and moderator variables (eg physical conditions, life styles, gastric microbiome, etc) linked to causal relationships, and their impact, should be recognized and controlled.
Radiation pneumonitis after definitive concurrent chemoradiotherapy with cisplatin/docetaxel for non‐small cell lung cancer: Analysis of dose‐volume parameters
Authors: Katsui Kuniaki , Ogata Takeshi , Watanabe Kenta , Katayama Norihisa , Kuroda Masahiro , Kiura Katsuyuki , Hiraki Takao , Maeda Yoshinobu , Toyooka Shinichi , Kanazawa Susumu
Published: May 2020

Background

Radiation pneumonitis (RP) is a major pulmonary adverse event of chest radiotherapy. The PACIFIC trial that identified durvalumab as an effective subsequent‐line therapy after concurrent chemoradiotherapy (CCRT) found that patients with grade 2 or higher RP may have to be excluded from treatment under certain criteria. The purpose of this study was to investigate the relationship between grade ≥2 RP and the parameters of dose‐volume histograms after CCRT with cisplatin/docetaxel for stage III non‐small cell lung cancer and conduct a subset analysis of severe RP that can lead to the permanent discontinuation of treatment per the PACIFIC trial criteria to help determine treatment strategy.

Methods

We calculated the percentage of the lung volume received at least 5 Gy (V5) and 20 Gy (V20), the mean lung dose (MLD), and the lung volume spared from a 5 Gy dose (VS5) to the total lung volume. Factors affecting the incidence of grade ≥2 RP were identified; severe RP was defined as grade ≥3 as well as grade 2 RP that required ≥10 mg prednisolone for at least 12 weeks.

Results

This study included 45 patients. On univariate analysis, all parameters and total lung volume were found to be significant predictors of grade ≥2 RP (P = .001, .003, .03, .004, and .02, respectively). On multivariate analysis, V20 was a significant predictive factor of grade ≥2 RP (P = .007). Severe RP developed in 6 of 37 patients (16.2%) whose V20 values were 35% or lower. On univariate analysis, only V20 was a significant predictor of severe RP in these patients (P = .01).

Conclusions

The best approach to reduce the rate of grade ≥2 RP is to maintain the V5, V20, MLD, and VS5 as low as possible during radiotherapy planning in patients receiving definitive CCRT with cisplatin/docetaxel.
Syntheses and Structure–Activity Relationships in Antibacterial Activity against Clostridium difficile and XBP1 Activation Property of 13‐[(N‐Alkylamino)methyl]‐8‐oxodihydrocoptisines
Authors: Li Jing , Zhang Hai‐Jing , Deng An‐Jun , Li Zhi‐Hong , Xing Ya‐Ling , Wu Lian‐Qiu , Qin Hai‐Lin
Published: May 2020

13‐[(N‐Alkylamino)methyl]‐8‐oxodihydrocoptisines were synthesized to evaluate antibacterial activity against Clostridium difficile and activating x‐box‐binding protein 1 (XBP1) activity, biological properties both associated with ulcerative colitis. Improving structural stability and ameliorating biological activity were major concerns. Different substituents on the structural modification site were involved to explore the influence of diverse structures on the bioactivities. The target compounds exhibited the desired activities with definite structure–activity relationship. In the series of 13‐[(N‐n‐alkylamino)methyl]‐8‐oxodihydrocoptisines, the length of n‐alkyl groups has a definite effect on the bioactivity, elongation of the length increasing the antibacterial activity. The synthesized compounds were determined to display strong or weak XBP1‐activating activity in vitro. The preliminary results of this study warrant further medicinal chemistry studies on these synthesized compounds.
The value of microcredentials: The employer's perspective
Authors: Gauthier Thomas
Published: May 2020

Background

Competency‐based hiring is beginning to catch on as employers insist on having a clearer understanding of an applicant's abilities before extending an offer of employment. Microcredentialing offers employees a mechanism to articulate their competency, and they offer employers a profound way to certify an applicant's abilities.

Purpose

To seek an understanding of the value of a microcredentialing structure through employer perspectives. The central research question is, do employers see value in a postsecondary micro‐credentialing structure?

Method

This qualitative case study uses Skill Acquisition Theory and cultivated twenty‐two industry professionals from various sectors, primarily from the early childhood education industry.

Results

Several themes emerged from the data: The industry is not satisfied with employee skills, competency is the new currency, seat time does not equal education, a policy for issuing and securing microcredentials is necessary.

Discussion

Employers were questioning the validity of a college transcript and suggested that applicants present microcredentials for key employment elements along with their transcript to certify further their ability to apply knowledge and skills.

Conclusions

It is concluded that microcredentials would be beneficial to the holder and employers. To increase the value of these credentials, the participants suggested using a registry to track and report microcredentials earned. It was further concluded that institutions need to develop governing rules for issuing a microcredential, rules similar to those governing transcripts to ascertain and protect the validity of the credential.
Single Peptide Backbone Surrogate Mutations to Regulate Angiotensin GPCR Subtype Selectivity
Authors: Vrettos Eirinaios I. , Valverde Ibai E. , Mascarin Alba , Pallier Patrick N. , Cerofolini Linda , Fragai Marco , Parigi Giacomo , Hirmiz Baydaa , Bekas Nick , Grob Nathalie M. , Stylos Evgenios Κ. , Shaye Hamidreza , Del Borgo Mark , Aguilar Marie‐Isabel , Magnani Francesca , Syed Nelofer , Crook Timothy , Waqif Emal , Ghazaly Essam , Cherezov Vadim , Widdop Robert E. , Luchinat Claudio , Michael‐Titus Adina T. , Mindt Thomas L. , Tzakos Andreas G.
Published: May 2020

Mutating the side‐chains of amino acids in a peptide ligand, with unnatural amino acids, aiming to mitigate its short half‐life is an established approach. However, it is hypothesized that mutating specific backbone peptide bonds with bioisosters can be exploited not only to enhance the proteolytic stability of parent peptides, but also to tune its receptor subtype selectivity. Towards this end, four [Y]6‐Angiotensin II analogues are synthesized where amide bonds have been replaced by 1,4‐disubstituted 1,2,3‐triazole isosteres in four different backbone locations. All the analogues possessed enhanced stability in human plasma in comparison with the parent peptide, whereas only two of them achieved enhanced AT2R/AT1R subtype selectivity. This diversification has been studied through 2D NMR spectroscopy and unveiled a putative more structured microenvironment for the two selective ligands accompanied with increased number of NOE cross‐peaks. The most potent analogue, compound 2, has been explored regarding its neurotrophic potential and resulted in an enhanced neurite growth with respect to the established agent C21.
Planar, Stair‐Stepped, and Twisted: Modulating Structure and Photophysics in Pyrene‐ and Benzene‐Fused N‐Heterocyclic Boranes
Authors: Krantz Kelsie E. , Weisflog Sarah L. , Frey Nathan C. , Yang Wenlong , Dickie Diane A. , Webster Charles Edwin , Gilliard Robert J.
Published: May 2020

Because of their rigidity, polycyclic aromatic hydrocarbons (PAHs) have become a significant building block in molecular materials chemistry. Fusion or doping of boron into PAHs is known to improve the optoelectronic properties by reducing the LUMO energy level. Herein, we report a comprehensive study on the syntheses, structures, and photophysical properties of a new class of fused N‐heterocyclic boranes (NHBs), pyrene‐ and benzene‐linked in a “Janus‐type” fashion (2–4, 6–9, and 11). Remarkably, these examples of fused NHBs display fluorescent properties, and collectively their emission spans the visible spectrum. The pyrene‐fused NHBs all display blue fluorescence, as the excitations are dominated by the pyrene core. In notable contrast, the emission properties of the benzene‐fused analogues are highly tunable and are dependent on the electronics of the NHB fragments (i.e., the functional group directly bound to the boron atoms). Pyrene‐fused 2–4 and 11 represent the only molecules in which the K‐region of pyrene is functionalized with NHB units, and while they exhibit distorted (twisted or stair‐stepped) pyrene cores, benzene‐fused 6–9 are planar. The electronic structure and optical properties of these materials were probed by computational studies, including an evaluation of aromaticity, electronic transitions, and molecular orbitals.
Design, Synthesis and Biological Evaluation of Highly Potent Simplified Archazolids
Authors: Rivière Solenne , Vielmuth Christin , Ennenbach Christiane , Abdelrahman Aliaa , Lemke Carina , Gütschow Michael , Müller Christa E. , Menche Dirk
Published: May 2020

The archazolids are potent antiproliferative compounds that have recently emerged as a novel class of promising anticancer agents. Their complex macrolide structures and scarce natural supply make the development of more readily available analogues highly important. Herein, we report the design, synthesis and biological evaluation of four simplified and partially saturated archazolid derivatives. We also reveal important structure‐activity relationship data as well as insights into the pharmacophore of these complex polyketides.
Oral arsenic trioxide, all‐trans retinoic acid, and ascorbic acid maintenance after first complete remission in acute promyelocytic leukemia: Long‐term results and unique prognostic indicators
Authors: Gill Harinder S. , Yim Rita , Kumana Cyrus R. , Tse Eric , Kwong Yok‐Lam
Published: May 2020

Background

The role of arsenic trioxide (As2O3) in the maintenance of first complete remission (CR1) in acute promyelocytic leukemia (APL) is unclear.

Methods

A total of 129 consecutive adult patients with APL of all risk categories who achieved CR1 with conventional induction (all‐trans retinoic acid [ATRA]/daunorubicin) and consolidation (daunorubicin/cytarabine [induction daunorubicin and consolidation omitted for age ≥70 years]) underwent maintenance comprising ATRA (45 mg/m2/day), oral As2O3 (10 mg/day), and ascorbic acid (1 g/day) (AAA) for 2 weeks every 2 months for 2 years.

Results

Over a 17‐year period from August 1, 2002, to July 31, 2019, 63 men and 66 women (median age, 46 years [range, 18‐82 years]) received AAA maintenance, which was already completed in 117 patients. At a median follow‐up of 100 months (range, 8‐215 months), 17 patients (13%) developed first relapse (R1) (hematologic, n = 14; molecular, n = 3) after a median of 19 months (range, 7‐96 months) from CR1. Two R1 patients had concomitant central nervous system (CNS) involvement. All patients achieved CR2 with oral As2O3‐based salvage. Five patients had a subsequent relapse and died. Eight patients died of unrelated causes while still in CR1. The 5‐year and 10‐year rates of relapse‐free survival (RFS) were 89% and 85%, respectively. The 5‐year and 10‐year rates of overall survival (OS) were 94% and 87%, respectively. Multivariate analysis showed that inferior RFS was associated with FLT3‐ITD (P = .005) and CNS involvement on presentation (P = .004), and inferior OS was associated with therapy‐related APL (P = .03), FLT3‐ITD (P = .03), and relapse (P = .03). The safety profile was favorable, with no grade 3/4 organ toxicities.

Conclusion

CR1 maintenance with AAA is safe and results in favorable long‐term survival in patients with APL.
Helquats as Promoters of the Povarov Reaction: Synthesis of 1,2,3,4‐Tetrahydroquinoline Scaffolds Catalyzed by Helicene‐Viologen Hybrids
Authors: Reyes‐Gutiérrez Paul E. , Amatov Tynchtyk T. , Švec Pavel , Císařová Ivana , Šaman David , Pohl Radek , Teplý Filip , Pospíšil Lubomír
Published: May 2020

Helquats (HQs) are structurally linked to helicenes and viologens, and they represent an attractive field of research in chemistry and medicinal chemistry. In the present work they were used as catalysts for the synthesis of 1,2,3,4‐tetrahydroquinolines in good yields by the Povarov reaction. The substrate scope and the capability of different helquats to promote Povarov reactions are demonstrated. Studies to elucidate mechanistic details revealed that helquats act as single‐electron transfer oxidants through a cation‐radical mechanism. The screening of the catalytic activity of HQs confirmed that an active HQ must have a LUMO energy below −8.67 eV and the standard redox potential higher (less negative) than −1.2 V vs. the ferrocene/ferrocenium redox couple.