bluuebunny/crossref_metadata_2025 huggingface dataset:
The switch-like expression of heme-regulated kinase 1 mediates neuronal proteostasis following proteasome inhibition
Authors: Alvarez-Castelao Beatriz , tom Dieck Susanne , Fusco Claudia M , Donlin-Asp Paul , Perez Julio D , Schuman Erin M
Published: April 2020

We examined the feedback between the major protein degradation pathway, the ubiquitin-proteasome system (UPS), and protein synthesis in rat and mouse neurons. When protein degradation was inhibited, we observed a coordinate dramatic reduction in nascent protein synthesis in neuronal cell bodies and dendrites. The mechanism for translation inhibition involved the phosphorylation of eIF2α, surprisingly mediated by eIF2α kinase 1, or heme-regulated kinase inhibitor (HRI). Under basal conditions, neuronal expression of HRI is barely detectable. Following proteasome inhibition, HRI protein levels increase owing to stabilization of HRI and enhanced translation, likely via the increased availability of tRNAs for its rare codons. Once expressed, HRI is constitutively active in neurons because endogenous heme levels are so low; HRI activity results in eIF2α phosphorylation and the resulting inhibition of translation. These data demonstrate a novel role for neuronal HRI that senses and responds to compromised function of the proteasome to restore proteostasis.
Squamous trans-differentiation of pancreatic cancer cells promotes stromal inflammation
Authors: Somerville Tim DD , Biffi Giulia , Daßler-Plenker Juliane , Hur Stella K , He Xue-Yan , Vance Krysten E , Miyabayashi Koji , Xu Yali , Maia-Silva Diogo , Klingbeil Olaf , Demerdash Osama E , Preall Jonathan B , Hollingsworth Michael A , Egeblad Mikala , Tuveson David A , Vakoc Christopher R
Published: April 2020

A highly aggressive subset of pancreatic ductal adenocarcinomas undergo trans-differentiation into the squamous lineage during disease progression. Here, we investigated whether squamous trans-differentiation of human and mouse pancreatic cancer cells can influence the phenotype of non-neoplastic cells in the tumor microenvironment. Conditioned media experiments revealed that squamous pancreatic cancer cells secrete factors that recruit neutrophils and convert pancreatic stellate cells into cancer-associated fibroblasts (CAFs) that express inflammatory cytokines at high levels. We use gain- and loss-of-function approaches to show that squamous-subtype pancreatic tumor models become enriched with neutrophils and inflammatory CAFs in a p63-dependent manner. These effects occur, at least in part, through p63-mediated activation of enhancers at pro-inflammatory cytokine loci, which includesIL1AandCXCL1as key targets. Taken together, our findings reveal enhanced tissue inflammation as a consequence of squamous trans-differentiation in pancreatic cancer, thus highlighting an instructive role of tumor cell lineage in reprogramming the stromal microenvironment.
Searching for the genetic key to a long and healthy life
Authors: Deelen Joris
Published: April 2020

A study of over 40,000 individuals suggests that carrying a small number of ultra-rare genetic variants is associated with a longer lifespan.
BRAF inhibition curtails IFN‐gamma‐inducible PD‐L1 expression and upregulates the immunoregulatory protein galectin‐1 in melanoma cells
Authors: Górniak Patryk , Wasylecka‐Juszczyńska Maja , Ługowska Iwona , Rutkowski Piotr , Polak Anna , Szydłowski Maciej , Juszczyński Przemysław
Published: April 2020

Although melanoma is considered one of the most immunogenic malignancies, spontaneous T‐cell responses to melanoma antigens are ineffective due to tumor cell‐intrinsic or microenvironment‐driven immune evasion mechanisms. For example, oncogenic BRAF V600E mutation in melanoma cells fosters tumor immune escape by modulating cell immunogenicity and microenvironment composition. BRAF inhibition has been shown to increase melanoma cell immunogenicity, but these effects are transient and long‐term responses are uncommon. For these reasons, we aimed to further characterize the role of BRAF‐V600E mutation in the modulation of PD‐L1, a known immunoregulatory molecule, and galectin‐1 (Gal‐1), a potent immunoregulatory lectin involved in melanoma immune privilege. We report herein that vemurafenib downregulates IFN‐γ‐induced PD‐L1 expression by interfering with STAT1 activity and by decreasing PD‐L1 protein translation. Surprisingly, melanoma cells exposed to vemurafenib expressed higher levels of Gal‐1. In coculture experiments, A375 melanoma cells pretreated with vemurafenib induced apoptosis of interacting Jurkat T cells, whereas genetic inhibition of Gal‐1 in these cells restored the viability of cocultured T lymphocytes, indicating that Gal‐1 contributes to tumor immune escape. Importantly, Gal‐1 plasma concentration increased in patients progressing on BRAF/MEK inhibitor treatment, but remained stable in responding patients. Taken together, these results suggest a two‐faceted nature of BRAF inhibition‐associated immunomodulatory effects: an early immunostimulatory activity, mediated at least in part by decreased PD‐L1 expression, and a delayed immunosuppressive effect associated with Gal‐1 induction. Importantly, our observations suggest that Gal‐1 might be utilized as a potential biomarker and a putative therapeutic target in melanoma patients.
Dangerous myths compel authorities to reemphasize alcohol's risks
Authors: Enos Gary
Published: April 2020

At a time when social media buzz takes full advantage of people's suddenly surplus idleness, dangerous myth often can overtake sound science. Despite compelling research evidence that alcohol consumption, particularly at high doses, compromises immune function (see “Effects on lung, immune function offer warning for drinking in crisis,” ADAW, April 20; https://onlinelibrary.wiley.com/doi/full/10.1002/adaw.32693), health authorities still are finding it necessary to counteract messaging that could move some individuals toward greater alcohol use during the novel coronavirus crisis.
Bioinspired Precision Engineering of Three‐Dimensional Epithelial Stem Cell Microniches
Authors: Prina Elisabetta , Amer Mahetab H. , Sidney Laura , Tromayer Maximilian , Moore Jonathan , Liska Robert , Bertolin Marina , Ferrari Stefano , Hopkinson Andrew , Dua Harminder , Yang Jing , Wildman Ricky , Rose Felicity R. A. J.
Published: April 2020

Maintenance of the epithelium relies on stem cells residing within specialized microenvironments, known as epithelial crypts. Two‐photon polymerization (2PP) is a valuable tool for fabricating 3D micro/nanostructures for stem cell niche engineering applications. Herein, biomimetic gelatin methacrylate‐based constructs, replicating the precise geometry of the limbal epithelial crypt structures (limbal stem cell “microniches”) as an exemplar epithelial niche, are fabricated using 2PP. Human limbal epithelial stem cells (hLESCs) are seeded within the microniches in xeno‐free conditions to investigate their ability to repopulate the crypts and the expression of various differentiation markers. Cell proliferation and a zonation in cell phenotype along the z‐axis are observed without the use of exogenous signaling molecules. Significant differences in cell phenotype between cells located at the base of the microniche and those situated towards the rim are observed, demonstrating that stem cell fate is strongly influenced by its location within a niche and the geometrical details of where it resides. This study provides insight into the influence of the niche’s spatial geometry on hLESCs and demonstrates a flexible approach for the fabrication of biomimetic crypt‐like structures in epithelial tissues. This has significant implications for regenerative medicine applications and can ultimately lead to implantable synthetic “niche‐based” treatments.
Activation of the SOX‐5, SOX‐6, and SOX‐9 Trio of Transcription Factors Using a Gene‐Activated Scaffold Stimulates Mesenchymal Stromal Cell Chondrogenesis and Inhibits Endochondral Ossification
Authors: Raftery Rosanne M. , Gonzalez Vazquez Arlyng G. , Chen Gang , O'Brien Fergal J.
Published: April 2020

Current treatments for articular cartilage defects relieve symptoms but often only delay cartilage degeneration. Mesenchymal stem cells (MSCs) have shown chondrogenic potential but tend to undergo endochondral ossification when implanted in vivo. Harnessing factors governing joint development to functionalize biomaterial scaffolds, termed developmental engineering, might allow to prime host MSCs to regenerate mature articular cartilage in situ without requiring cell isolation or ex vivo expansion. Therefore, the aim of this study is to develop a gene‐activated scaffold capable of delivering developmental cues to host MSCs, thus priming MSCs for articular cartilage differentiation and inhibiting endochondral ossification. It is shown that delivery of the SOX‐Trio induced MSCs to over‐express COL2A1 and ACAN and deposit a sulfated and collagen type II rich extracellular matrix while hypertrophic gene expression and collagen type X deposition is inhibited. When cell‐free SOX‐Trio‐activated scaffolds are implanted ectopically in vivo, they induced spontaneous chondrogenesis without evidence of hypertrophy. MSCs pre‐cultured on SOX‐Trio‐activated scaffolds prior to implantation differentiate into phenotypically stable chondrocytes as evidenced by a lack of collagen X expression or vascular invasion. This SOX‐trio‐activated scaffold represents a potent, single treatment, developmentally inspired strategy to prime MSCs in situ for articular cartilage defect repair.
Exploring Circulating Tumor Cells in Cholangiocarcinoma Using a Novel Glycosaminoglycan Probe on a Microfluidic Platform
Authors: Gopinathan Priya , Chiang Nai‐Jung , Bandaru Anandaraju , Sinha Anirban , Huang Wen‐Yen , Hung Shang‐Cheng , Shan Yan‐Shen , Lee Gwo‐Bin
Published: April 2020

The search of alternative approaches to epithelial cell adhesion molecule (EpCAM), for the isolation of circulating tumor cells (CTC), is on the rise. This work attempts at evaluating the feasibility of using a new glycosaminoglycan, SCH45, as a probe to isolate CTCs from the peripheral blood of 65 advanced/metastatic cholangiocarcinoma (CCA) patients. The positive enrichment of CTCs from 1 mL of blood using SCH45‐bound magnetic beads and subsequent staining on an integrated microfluidic platform is demonstrated. Results detailing CTC concentrations averaging ≥1 CTCs mL−1 of blood are shown, and a conventional protein biomarker, EpCAM, has been used to corroborate the finding that 100% of the patients possess CTCs in their blood. Studies detailing the use of CTCs in the prognostic monitoring and treatment effectiveness of advanced/metastatic CCA are scarce, and the isolation of CTCs from all CCA patients tested has not been reported yet. A strong correlation between CTC counts and disease progression at the time of and/or in advance of radiographic imaging in patients receiving chemotherapy is also reported. This study is one of its kind with the new probe and reduced sample volume and has potential for use in CCA diagnosis and prognosis in the near future.
Dehydration‐Triggered Ionic Channel Engineering in Potassium Niobate for Li/K‐Ion Storage
Authors: Zhang Shilin , Fan Qining , Liu Ye , Xi Shibo , Liu Xiufan , Wu Zhibin , Hao Junnan , Pang Wei Kong , Zhou Tengfei , Guo Zaiping
Published: April 2020

Boosting charge transfer in materials is critical for applications involving charge carriers. Engineering ionic channels in electrode materials can create a skeleton to manipulate their ion and electron behaviors with favorable parameters to promote their capacity and stability. Here, tailoring of the atomic structure in layered potassium niobate (K4Nb6O17) nanosheets and facilitating their application in lithium and potassium storage by dehydration‐triggered lattice rearrangement is reported. The spectroscopy results reveal that the interatomic distances of the NbO coordination in the engineered K4Nb6O17 are slightly elongated with increased degrees of disorder. Specifically, the engineered K4Nb6O17 shows enhanced electrical and ionic conductivity, which can be attributed to the enlarged interlamellar spacing and subtle distortions in the fine atomic arrangements. Moreover, subsequent experimental results and calculations demonstrate that the energy barrier for Li+/K+ diffusion is significantly lower than that in pristine K4Nb6O17. Interestingly, the diffusion coefficient of K+ is one order of magnitude higher than that of Li+ , and the engineered K4Nb6O17 presents superior electrochemical performance for K+ to Li+ . This work offers an ionic engineering strategy to enable fast and durable charge transfer in materials, holding great promise for providing guidance for the material design of related energy storage systems.
Toward 2D Magnets in the (MnBi2Te4)(Bi2Te3)n Bulk Crystal
Authors: Wu Jiazhen , Liu Fucai , Liu Can , Wang Yong , Li Changcun , Lu Yangfan , Matsuishi Satoru , Hosono Hideo
Published: April 2020

2D magnets and their engineered magnetic heterostructures are intriguing materials for both fundamental physics and application prospects. On the basis of the recently discovered intrinsic magnetic topological insulators (MnBi2Te4)(Bi2Te3)n, here, a new type of magnet, in which the magnetic layers are separated by a large number of non‐magnetic layers and become magnetically independent, is proposed. This magnet is named as a single‐layer magnet, regarding the vanishing interlayer exchange coupling. Theoretical calculations and magnetization measurements indicate that, the decoupling of the magnetic layers starts to emerge from n = 2 and 3, as revealed by a unique slow‐relaxation behavior below a ferromagnetic‐type transition at Tc = 12–14 K. Magnetization data analysis shows that the proposed new magnetic states have a strong uniaxial anisotropy along the c‐axis, forming an Ising‐type magnetic structure, where Tc is the ordering temperature for each magnetic layer. The characteristic slow relaxation, which exists only along the c‐axis but is absent along the ab plane, can be ascribed to interlayer coherent spin rotation and/or intralayer domain wall movement. The present results will stimulate further theoretical and experimental investigations for the prototypical magnetic structures, and their combination with the topological surface states may lead to exotic physical properties.
Nickel‐Catalyzed Decarboxylative Cyclization of Isatoic Anhydrides with Carbodiimides: Synthesis of 2,3‐Dihydroquinazolin‐4(1H)‐ones
Authors: Zhang Zhen , Qin Ziqiang , Chang Wenxu , Li Jiazhu , Fan Ruoqian , Wu Xing , Guo Rongrong , Xie Xiangqi , Zhou Lanxin
Published: April 2020

In this study, a nickel‐catalyzed decarboxylative cyclization of isatoic anhydrides with carbodiimides was developed. This protocol realized the direct introduction of carbodiimides into heterocyclic compounds under an in situ generated Ni(0) complex. Synthetically, this methodology provides a simplified and secure new approach for the preparation of 2‐imino‐2,3‐dihydroquinazolin‐4(1H)‐ones. The control experiments and DFT theoretical calculations indicated that the Ni(0)‐catalyzed process is of central importance to the entire transformation.

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Diastereoselective Synthesis of Tetrahydroquinolines Bearing Oxindole Scaffolds via Annulation of in Situ Generated p‐Quinone Methides
Authors: Wang Junwei , Zhao Lei , Zhao Lin , Pan Xiang , Lv Cheng , Zhi Ying , Wang Ai , Zhao Kun , Hu Lihong
Published: April 2020

A diastereoselective [4+2] annulation reaction between in situ generated p‐quinone methides and isatin‐derived enoates has been developed. In the presence of manganese dioxide as an oxidant, a variety of tosylaminophenyl‐substituted p‐quinone methide intermediates can be readily generated in an in situ fashion. Without pre‐preparation of p‐QMs, this unprecedented cascade reaction proceeds efficiently under mild conditions, providing a straightforward route to synthesize 4‐phenyl‐substituted tetrahydroquinolines bearing 3,3’‐spirooxindole scaffolds in good yields.

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Tracking the Influence of Thermal Expansion and Oxygen Vacancies on the Thermal Stability of Ni‐Rich Layered Cathode Materials
Authors: Lee Eunkang , Muhammad Shoaib , Kim Taewhan , Kim Hyunchul , Lee Wontae , Yoon Won‐Sub
Published: April 2020

The ever‐growing demand for high‐energy lithium‐ion batteries in portable electronics and electric vehicles has triggered intensive research efforts over the past decade. An efficient strategy to boost the energy and power density of lithium‐ion batteries is to increase the Ni content in the cathode materials. However, a higher Ni content in the cathode materials gives rise to safety issues. Herein, thermal expansion and oxygen vacancies are proposed as new critical factors that affect the thermal stability of charged Ni‐rich cathode materials based on a systematic synchrotron‐based X‐ray study of Li0.33Ni0.5+xCo0.2Mn0.3‐xO2 (x = 0, 0.1, 0.2) cathode materials during a heating process. Charged cathode materials with higher Ni contents show larger thermal expansion, which accelerates transition metal migration to the Li layers. Oxygen vacancies are formed and accumulate mainly around Ni ions until the layered‐to‐spinel phase transition begins. The oxygen vacancies also facilitate transition metal migration to the Li layers. Thermal expansion and the presence of oxygen vacancies decrease the energy barrier for cation migration and facilitate the phase transitions in charged cathode materials during the heating process. These results provide valuable guidance for developing new cathode materials with improved safety characteristics.
Transferrin Receptor 1 Regulates Thermogenic Capacity and Cell Fate in Brown/Beige Adipocytes
Authors: Li Jin , Pan Xiaohan , Pan Guihua , Song Zijun , He Yao , Zhang Susu , Ye Xueru , Yang Xiang , Xie Enjun , Wang Xinhui , Mai Xudong , Yin Xiangju , Tang Biyao , Shu Xuan , Chen Pengyu , Dai Xiaoshuang , Tian Ye , Yao Liheng , Han Mulan , Xu Guohuan , Zhang Huijie , Sun Jia , Chen Hong , Wang Fudi , Min Junxia , Xie Liwei
Published: April 2020

Iron homeostasis is essential for maintaining cellular function in a wide range of cell types. However, whether iron affects the thermogenic properties of adipocytes is currently unknown. Using integrative analyses of multi‐omics data, transferrin receptor 1 (Tfr1) is identified as a candidate for regulating thermogenesis in beige adipocytes. Furthermore, it is shown that mice lacking Tfr1 specifically in adipocytes have impaired thermogenesis, increased insulin resistance, and low‐grade inflammation accompanied by iron deficiency and mitochondrial dysfunction. Mechanistically, the cold treatment in beige adipocytes selectively stabilizes hypoxia‐inducible factor 1‐alpha (HIF1α), upregulating the Tfr1 gene, and thermogenic adipocyte‐specific Hif1α deletion reduces thermogenic gene expression in beige fat without altering core body temperature. Notably, Tfr1 deficiency in interscapular brown adipose tissue (iBAT) leads to the transdifferentiation of brown preadipocytes into white adipocytes and muscle cells; in contrast, long‐term exposure to a low‐iron diet fails to phenocopy the transdifferentiation effect found in Tfr1‐deficient mice. Moreover, mice lacking transmembrane serine protease 6 (Tmprss6) develop iron deficiency in both inguinal white adipose tissue (iWAT) and iBAT, and have impaired cold‐induced beige adipocyte formation and brown fat thermogenesis. Taken together, these findings indicate that Tfr1 plays an essential role in thermogenic adipocytes via both iron‐dependent and iron‐independent mechanisms.
Heterostructure SnSe2/ZnSe@PDA Nanobox for Stable and Highly Efficient Sodium‐Ion Storage
Authors: Liu Pei , Han Jun , Zhu Kunjie , Dong Zihao , Jiao Lifang
Published: April 2020

Rationally designed electrode materials with high capacity, long cycle life, and low cost are indispensable for sodium‐ion batteries. Herein, a hierarchical nanobox consisting of a heterojunction bimetallic selenide yolk and polydopamine shell (denoted as SnSe2/ZnSe@PDA) is engineered and fabricated successfully. Owing to the charge redistribution and lattice distortion at the hetero‐phase boundaries, Na+ ions can be easily adsorbed and transferred swiftly, facilitating the reaction kinetics and promoting cycling behavior. By means of the hollow structure and elastic polymer shell, this approach can synergistically alleviate volume fluctuation and the aggregation of active nanomaterials during cycling. This material delivers a high reversible capacity of 616 mA h g‐1 at 1 A g‐1 over 1000 long‐term cycles, and superior rate capability, which provides more possibilities for the practical applications of energy storage in the future.
Relief pain of symptomatic annular pancreas in adults: A report of two cases
Authors: Shie Chang‐Bih , Lu I‐Cheng , Wu I‐Ting
Published: April 2020

Annular pancreas is a rare disease and was first described by Tiedman in 1818. The anomaly is often discovered in neonates or during the first year of life. The clinical presentation can be less severe in the case of young children, and the anomaly can remain asymptomatic and may be discovered fortuitously in adult patients. In adult patients with annular pancreas, the common symptoms include cramping epigastric pain and postprandial abdominal fullness. Associated conditions include duodenal ulcers, acute pancreatitis, carcinoma of the pancreatic head, biliary colic in association with biliary obstruction and jaundice, and obstruction of the gastric outlet. Here, we successfully treated the cases of two adult patients with symptomatic annular pancreas, and we discuss the available diagnostic and therapeutic modalities for the same.
The association ofNative Americangenetic ancestry and high‐density lipoprotein cholesterol: A representative study of a highly admixed population
Authors: Fritz Jimena , Lopez‐Ridaura Ruy , Choudhry Shweta , Razo Christian , Lamadrid‐Figueroa Hector
Published: April 2020

Objective

Hispanic populations typically show a high prevalence of dyslipidemias, especially of low high‐density lipoproteins (HDLs) or HDL cholesterol. Highly admixed populations are ideal groups to clarify the role of genetic ancestry on HDL concentrations, isolating it from that of other factors. The objective of this study was to estimate the association between Native American genetic ancestry and HDL‐cholesterol levels independent of socioeconomic factors in a representative sample of the Mexican population.

Methods

We used data from the Mexican National Health Survey 2000, analyzing 1647 subjects from whom stored DNA samples and HDL measurements were available. To estimate proportional genetic ancestry (Native American, African, and European), we used a 107 genetic ancestry informative marker panel with the software STRUCTURE. To estimate the association between genetic ancestry and low HDL levels, we fitted logistic regression models with the percentage of Native American genetic ancestry, in quartiles, as the main predictor.

Results

Mean HDL levels were 38.9 mg/dL, with 62% of subjects having levels below 40 mg/dL. Participants had on average 53.6% Native American, 39% European, and 7.3% African genetic ancestry. Those in the fourth quartile of Native American genetic ancestry had 35% higher odds of having low HDL‐cholesterol relative to those in the first quartile (odds ratio, 1.35; 95% confidence interval, 0.99‐1.81) after adjustment for socioeconomic level and other covariates, although the association is clearly nonlinear.

Conclusion

Native American genetic ancestry seems to play a small but distinct role in the development of low HDL cholesterol levels.
Ruthenium(II)‐ and Copper(II)‐Mediated Synthesis of Trisubstituted Pyrroles from Isoxazoles and Acrylate Esters
Authors: Kumar Pravin , Kapur Manmohan
Published: April 2020

An efficient ruthenium(II)‐ and copper(II)‐mediated, “one‐pot” synthesis of pyrroles has been reported. The reaction most probably proceeds via a reductive cleavage of isoxazoles. This protocol results in the synergistic formation of new C−C, C−N bonds, which leads to a simple and an efficient method for the synthesis of highly functionalized pyrroles from isoxazoles and acrylate esters.
Cucurbit[n]uril‐Based Supramolecular Frameworks Assembled through Outer‐Surface Interactions
Authors: Huang Ying , Gao Rui‐Han , Liu Ming , Chen Li‐Xia , Ni Xin‐Long , Xiao Xin , Cong Hang , Zhu Qian‐Jiang , Chen Kai , Tao Zhu
Published: April 2020

Porous materials, especially metal–organic frameworks, covalent organic frameworks, and supramolecular organic frameworks, are widely used in heterogeneous catalysis, adsorption, and ion exchange. Cucurbit[n]urils (Q[n]s) suitable building units for porous materials because they possess cavities with neutral electrostatic potential, portal carbonyls with negative electrostatic potential, and outer surfaces with positive electrostatic potential, which may result in the formation of Q[n]‐based supramolecular frameworks (QSFs) assembled through the interaction of guests within Q[n]s, the coordination of Q[n]s with metal ions, and outer‐surface interaction of Q[n]s (OSIQ). This review summarizes the various QSFs assembled via OSIQs. The QSFs can be classified as being assembled by 1) self‐induced OSIQ, 2) anion‐induced OSIQ, and 3) aromatic‐induced OSIQ. The design and construction of QSFs with novel structures and specific functional properties may establish a new research direction in Q[n] chemistry.
Atomically Dispersed Nickel(I) on an Alloy‐Encapsulated Nitrogen‐Doped Carbon Nanotube Array for High‐Performance Electrochemical CO2 Reduction Reaction
Authors: Zhang Tianyu , Han Xu , Yang Hongbin , Han Aijuan , Hu Enyuan , Li Yaping , Yang Xiao‐qing , Wang Lei , Liu Junfeng , Liu Bin
Published: April 2020

Single‐atom catalysts (SACs) show great promise for electrochemical CO2 reduction reaction (CRR), but the low density of active sites and the poor electrical conduction and mass transport of the single‐atom electrode greatly limit their performance. Herein, we prepared a nickel single‐atom electrode consisting of isolated, high‐density and low‐valent nickel(I) sites anchored on a self‐standing N‐doped carbon nanotube array with nickel–copper alloy encapsulation on a carbon‐fiber paper. The combination of single‐atom nickel(I) sites and self‐standing array structure gives rise to an excellent electrocatalytic CO2 reduction performance. The introduction of copper tunes the d‐band electron configuration and enhances the adsorption of hydrogen, which impedes the hydrogen evolution reaction. The single‐nickel‐atom electrode exhibits a specific current density of −32.87 mA cm−2 and turnover frequency of 1962 h−1 at a mild overpotential of 620 mV for CO formation with 97 % Faradic efficiency.
Electrosynthesis of Dihydropyrano[4,3‐b]indoles Based on a Double Oxidative [3+3] Cycloaddition
Authors: Choi Subin , Park Jinhwi , Yu Eunsoo , Sim Jeongwoo , Park Cheol‐Min
Published: April 2020

Oxidative [3+3] cycloadditions offer an efficient route for six‐membered‐ring formation. This approach has been realized based on an electrochemical oxidative coupling of indoles/enamines with active methylene compounds followed by tandem 6π‐electrocyclization leading to the synthesis of dihydropyrano[4,3‐b]indoles and 2,3‐dihydrofurans. The radical–radical cross‐coupling of the radical species generated by anodic oxidation combined with the cathodic generation of the base from O2 allows for mild reaction conditions for the synthesis of structurally complex heterocycles.
Molecular Sieving of C2‐C3 Alkene from Alkyne with Tuned Threshold Pressure in Robust Layered Metal–Organic Frameworks
Authors: Ke Tian , Wang Qingju , Shen Jin , Zhou Jingyi , Bao Zongbi , Yang Qiwei , Ren Qilong
Published: April 2020

C2‐C3 alkyne/alkene separation is of great importance; however, designing materials for an efficient molecular sieving of alkenes from alkynes remains challenging. Now, two hydrolytically stable layered MOFs, [Cu(dps)2(GeF6)] (GeFSIX‐dps‐Cu, dps=4,4′‐dipyridylsulfide) and [Zn(dps)2(GeF6)] (GeFSIX‐dps‐Zn), can achieve almost complete exclusion of both C3H6 and C2H4 from their alkyne analogues. GeFSIX‐dps‐Cu displays a notable advanced threshold pressure for alkynes adsorption and thus substantial uptakes at lower pressures, providing record C3H4/C3H6 uptake ratios and capacity‐enhanced C2H2/C2H4 sieving for a wide composition range. Metal substitution (Zn to Cu) affords fine tuning of linker rotation and layer stacking, creating slightly expanded pore aperture and interlayer space coupled with multiple hydrogen‐bonding sites, allowing easier entrance of alkyne while excluding alkene. Breakthrough experiments confirmed tunable sieving by these MOFs for C3H4/C3H6 and C2H2/C2H4 mixtures.
Target‐Directed Azide‐Alkyne Cycloaddition for Assembling HIV‐1 TAR RNA Binding Ligands
Authors: Paul Rakesh , Dutta Debasish , Paul Raj , Dash Jyotirmayee
Published: April 2020

The highly conserved HIV‐1 transactivation response element (TAR) binds to the trans‐activator protein Tat and facilitates viral replication in its latent state. The inhibition of Tat–TAR interactions by selectively targeting TAR RNA has been used as a strategy to develop potent antiviral agents. Therefore, HIV‐1 TAR RNA represents a paradigmatic system for therapeutic intervention. Herein, we have employed biotin‐tagged TAR RNA to assemble its own ligands from a pool of reactive azide and alkyne building blocks. To identify the binding sites and selectivity of the ligands, the in situ cycloaddition has been further performed using control nucleotide (TAR DNA and TAR RNA without bulge) templates. The hit triazole‐linked thiazole peptidomimetic products have been isolated from the biotin‐tagged target templates using streptavidin beads. The major triazole lead generated by the TAR RNA presumably binds in the bulge region, shows specificity for TAR RNA over TAR DNA, and inhibits Tat–TAR interactions.
In Situ Pyrolysis Tracking and Real‐Time Phase Evolution: From a Binary Zinc Cluster to Supercapacitive Porous Carbon
Authors: Wang Yi‐Fan , Liang Yiyu , Wu Yan‐Fang , Yang Jian , Zhang Xu , Cai Dandan , Peng Xu , Kurmoo Mohamedally , Zeng Ming‐Hua
Published: April 2020

The in situ tracking of the pyrolysis of a binary molecular cluster [Zn7(μ3‐CH3O)6(L)6][ZnLCl2]2 is presented with one brucite disk and two mononuclear fragments (L=mmimp: 2‐methoxy‐6‐((methylimino)‐methyl)phenolate) to porous carbon using TG‐MS from 30 to 900 °C. Following up the spilled gas product during the decomposed reaction of zinc cluster along the temperature rising, and in conjunction with XRD, SEM, BET and other materials characterization, where three key steps were observed: 1) cleavage of the bulky external ligand; 2) reduction of ZnO and 3) volatilization of Zn. The real‐time‐dependent phase‐sequential evolution of the remaining products and the processing of pore forming template transformation are proposed simultaneously. The porous carbon structure featuring a uniform nano‐sized pore distribution synthesized at 900 °C with the highest surface area of 1644 m2 g−1 and pore volume of 0.926 cm3 g−1 exhibits the best known capacitance of 662 F g−1 at 0.5 A g−1.
Backbone‐Directed Self‐Assembly of Interlocked Molecular Cyclic Metalla[3]Catenanes
Authors: Feng Ting , Li Xin , An Yuan‐Yuan , Bai Sha , Sun Li‐Ying , Li Yang , Wang Yao‐Yu , Han Ying‐Feng
Published: April 2020

The efficient backbone‐directed self‐assembly of cyclic metalla[3]catenanes by the combination of tetrachloroperylenediimide (TCPDI)‐based dinuclear rhodium(III) clips and 4,4′‐diazopyridine or 4,4′‐dipyridylethylene ligands is realized in a single‐step strategy. The topology and coordination geometry of the cyclic metalla[3]catenanes are characterized by NMR spectroscopy, ESI‐TOF‐MS spectrometry, UV/Vis‐NIR spectroscopy, and X‐ray diffraction studies. The most remarkable feature of the formed cyclic metalla[3]catenane is that it contains π‐aggregates (ca. 2.6 nm) incorporating six TCPDIs. Further studies revealed that cyclic metalla[3]catenanes can be converted reversibly to their corresponding sodium adducts and precursor building blocks, respectively. This strategy opens the possibility of generating unique supramolecular structures from discrete functional π‐aggregates with precise arrangements.
Photo‐promoted Skeletal Rearrangement of Phosphine–Borane Frustrated Lewis Pairs Involving Cleavage of Unstrained C−C σ‐Bonds
Authors: Ito Tatsuyoshi , Iwasawa Nobuharu , Takaya Jun
Published: April 2020

An unprecedented photo‐promoted skeletal rearrangement reaction of phosphine–borane frustrated Lewis pairs, o‐(borylaryl)phosphines, involving cleavage of an unstrained sp2C–sp3C σ‐bond is reported. The reaction realizes an efficient synthesis of cyclic phosphonium borate compounds. The reaction mechanism via a boranorcaradiene intermediate is proposed based on theoretical calculations. This work sheds light on the new photoreactivity of phosphine–borane FLPs.
Asymmetric Total Syntheses of Kopsane Alkaloids via a PtCl2‐Catalyzed Intramolecular [3+2] Cycloaddition
Authors: Jia Xuelei , Lei Honghui , Han Feipeng , Zhang Tao , Chen Ying , Xu Zhengshuang , Nakliang Pratanphorn , Choi Sun , Guo Yian , Ye Tao
Published: April 2020

A concise and asymmetric total synthesis of five kopsane alkaloids that share a unique heptacyclic caged ring system was accomplished. The key transformation in the sequence involved a remarkable PtCl2‐catalyzed intramolecular [3+2] cycloaddition, which allowed for the rapid assembly of pentacyclic carbon skeletons bearing 2,3‐quaternary functionalized indoline. Expeditious construction of diverse indoline scaffolds with excellent control of diastereoselectivity demonstrated the broad scope and versatility of this key transformation.
Strain Influences the Hydrogen Evolution Activity and Absorption Capacity of Palladium
Authors: Jansonius Ryan P. , Schauer Phil A. , Dvorak David J. , MacLeod Benjamin P. , Fork David K. , Berlinguette Curtis P.
Published: April 2020

Strain engineering can increase the activity and selectivity of an electrocatalyst. Tensile strain is known to improve the electrocatalytic activity of palladium electrodes for reduction of carbon dioxide or dioxygen, but determining how strain affects the hydrogen evolution reaction (HER) is complicated by the fact that palladium absorbs hydrogen concurrently with HER. We report here a custom electrochemical cell, which applies tensile strain to a flexible working electrode, that enabled us to resolve how tensile strain affects hydrogen absorption and HER activity for a thin film palladium electrocatalyst. When the electrodes were subjected to mechanically‐applied tensile strain, the amount of hydrogen that absorbed into the palladium decreased, and HER electrocatalytic activity increased. This study showcases how strain can be used to modulate the hydrogen absorption capacity and HER activity of palladium.
Achieving Superior Electrocatalytic Performance by Surface Copper Vacancy Defects during Electrochemical Etching Process
Authors: Guo Niankun , Xue Hui , Bao Amurisana , Wang Zihong , Sun Jing , Song Tianshan , Ge Xin , Zhang Wei , Huang Keke , He Feng , Wang Qin
Published: April 2020

Vacancy defects of catalysts have been extensively studied and proven to be beneficial to various electrocatalytic reactions. Herein, an ultra‐stable three‐dimensional PtCu nanowire network (NNW) with ultrafine size, self‐supporting rigid structure, and Cu vacancy defects has been developed. The vacancy defect‐rich PtCu NNW exhibits an outstanding performance for the oxygen reduction reaction (ORR), with a mass activity 14.1 times higher than for the commercial Pt/C catalyst (20 %.wt, JM), which is currently the best performance. The mass activity of the PtCu NNW for methanol oxidation reaction (MOR) is 17.8 times higher than for the commercial Pt/C catalyst. Density‐functional theory (DFT) calculations indicate that the introduction of Cu vacancies enhances the adsorption capacity of Pt atoms to the HO* intermediate and simultaneously weakens the adsorption for the O* intermediate. This work presents a facile strategy to assemble efficient electrocatalysts with abundant vacancy defects, at the same time, provides an insight into the ORR mechanism in acidic solution.
Revisiting the Limiting Factors for Overall Water‐Splitting on Organic Photocatalysts
Authors: Rahman Mohammad , Tian Haining , Edvinsson Tomas
Published: April 2020

In pursuit of inexpensive and earth abundant photocatalysts for solar hydrogen production from water, conjugated polymers have shown potential to be a viable alternative to widely used inorganic counterparts. The photocatalytic performance of polymeric photocatalysts, however, is very poor in comparison to that of inorganic photocatalysts. Most of the organic photocatalysts are active in hydrogen production only when a sacrificial electron donor (SED) is added into the solution, and their high performances often rely on presence of noble metal co‐catalyst (e.g. Pt). For pursuing a carbon neutral and cost‐effective green hydrogen production, unassisted hydrogen production solely from water is one of the critical requirements to translate a mere bench‐top research interest into the real world applications. Although this is a generic problem for both inorganic and organic types of photocatalysts, organic photocatalysts are mostly investigated in the half‐reaction, and have so far shown limited success in hydrogen production from overall water‐splitting. To make progress, this article exclusively discusses critical factors that are limiting the overall water‐splitting in organic photocatalysts. Additionally, we also have extended the discussion to issues related to stability, accurate reporting of the hydrogen production as well as challenges to be resolved to reach 10 % STH (solar‐to‐hydrogen) conversion efficiency.
Evaluation of a vacuum collection system in the preparation of PAN fibers by forcespinning for application in ultrafine particle filtration
Authors: Salussoglia Ana Isabela Pianowski , Tanabe Eduardo Hiromitsu , Aguiar Mônica Lopes
Published: April 2020

This study investigates the use of a vacuum collection system (VCS) in the forcespinning formation of polyacrylonitrile fibers. The surface of different filter media (substrates) has been modified for air filtration applications. The evaluation was made of the effects of collection time (60 and 180 s), VCS power (25, 50, 75, and 100%), needle size (30G ½″ and 26G ½″), and rotation speed (4,000 and 6,000 rpm). The main results were that higher substrate permeability constant in association with VCS led to a decrease in the porosity of the fiber layer, an increase of the VCS power led to increases in the collection efficiency and pressure drop, while the superficial porosity and fiber diameter decreased, and fiber collection time analysis showed that the longer collection time led to higher fiber diameter and smaller pressure drop. In all cases, the addition of the fiber layer caused increases in the pressure drop and collection efficiency, together with decreased permeability constant. Although the collection efficiency values for nanoparticles are not as expressive, these results are encouraging and indicate that VCS can be used to improve the performance of the filter medium.
Preparation of imidazole embedded polyurea microcapsule for latent curing agent
Authors: Zhao Liyang , Yang Xiaojun , Ma Limin , Li Qingyang
Published: April 2020

The IZ‐PU microcapsule‐type curing agent was prepared by interfacial polymerization method. The shell‐core structure of the IZ‐PU microcapsules was demonstrated by IR and SEM. The core content and coating efficiency of the IZ‐PU microcapsules were analyzed by DSC test of the one‐component adhesive consisting of IZ‐PU microcapsules and epoxy resin. The results showed that the IZ‐PU microcapsules is a proper latent curing agent to epoxy resin, its latency at room temperature is longer than 30 days.
Distribution of whale shark (Rhincodon typus) off northern Peru based on habitat suitability
Authors: Gonzalez‐Pestana Adriana , Maguiño Rossana , Mendoza Alejandra , Kelez Shaleyla , Ramírez‐Macías Dení
Published: April 2020

In the south‐eastern Pacific Ocean, few studies of whale sharks (Rhincodon typus) exist. In Peru, the northern coast has been identified as the area with the highest presence of whale sharks, yet their ecology in this area is poorly defined.

This study predicts the spatial distribution of whale sharks off coastal northern Peru (03°00′S–04°30′S) during La Niña and El Niño seasonal conditions, utilizing maximum entropy modelling. Between 2009 and 2018 (except for 2011), 347 whale sharks were geo‐referenced in northern Peru with greatest data recordings in the austral summer and spring during La Niña events.

Depth was the most important predictive variable for spatial distribution of whale sharks, followed by chlorophyll‐a. Sharks were predicted in shallower coastal waters in which chlorophyll‐a values are higher.

Habitat suitability was higher in the northern coastal part of the study area. Spring presents the most suitable environmental conditions for whale sharks, both during La Niña and El Niño conditions. The probability of whale shark presence in the north of Peru increases at higher chlorophyll‐a and sea surface temperature values. Therefore, whale sharks appear to aggregate seasonally in northern Peru, potentially exploiting rich foraging grounds.

In these areas of high suitability, whale sharks are susceptible to fisheries, bycatch, ship collisions, unmanaged tourism, and pollution; thus, management actions should focus in these areas.

This study represents a first step to understand the distribution and habitat suitability of whale shark in Peruvian waters. Further studies should identify suitable habitat for whale sharks in offshore areas. Also, these should focus on the connectivity of these aggregations with other localities in the south‐eastern Pacific in order to contribute to regional strategies for the conservation of this iconic species in this particular region.
Metal–Organic Framework Composites for Theragnostics and Drug Delivery Applications
Authors: Osterrieth Johannes W. M. , Fairen‐Jimenez David
Published: April 2020

Among a plethora of nano‐sized therapeutics, metal‐organic frameworks (MOFs) have been some of the most investigated novel materials for, predominantly, cancer drug delivery applications. Due to their large drug uptake capacities and slow‐release mechanisms, MOFs are desirable drug delivery vehicles that protect and transport sensitive drug molecules to target sites. The inclusion of other guest materials into MOFs to make MOF‐composite materials has added further functionality, from externally triggered drug release to improved pharmacokinetics and diagnostic aids. MOF‐composites are synthetically versatile and can include examples such as magnetic nanoparticles in MOFs for MRI image contrast and polymer coatings that improve the blood‐circulation time. From synthesis to applications, this review will consider the main developments in MOF‐composite chemistry for biomedical applications and demonstrate the potential of these novel agents in nanomedicine. It is concluded that, although vast synthetic progress has been made in the field, it requires now to develop more biomedical expertise with a focus on rational model selection, a major comparative toxicity study, and advanced targeting techniques.
A simplified method for the efficient purification and refolding of recombinant human TRAIL
Authors: Zhang Zhenjiang , Hahn Su Bin , Cao Thong M. , King Michael R.
Published: April 2020

Tumor necrosis factor (TNF)‐related apoptosis‐inducing ligand (TRAIL) belongs to the TNF cytokine superfamily that specifically induces apoptosis in a broad spectrum of human cancer cell lines but not in most healthy cells. The antitumor potential of recombinant human TRAIL (rhTRAIL) has attracted great attention among biologists and oncologists. However, attempts to express rhTRAIL in Escherichia coli often results in limited yield of bioactive protein due to the formation of inclusion bodies (IBs), which are dense insoluble particulate protein aggregates inside cells. We describe herein a highly simplified method to produce pure bioactive rhTRAIL using E. coli. The method is straightforward and requires only basic laboratory equipment, with highly efficient purification and high yield of renaturation, and may also be applied to produce other proteins that form IBs in E. coli.
Urachal carcinoma: Impact of recurrence pattern and lymphadenectomy on long‐term outcomes
Authors: Duan Fangfang , Zhai Wenyu , Zhang Bei , Guo Shengjie
Published: April 2020

Background

Urachal carcinoma is a rare nonurothelial malignant tumor with high rates of local recurrence and systemic metastasis. Although radical resection is widely considered the standard treatment, there is still a debate regarding the benefits of lymphadenectomy. To explore these factors, we investigated the recurrence pattern of urachal cancer and the impact of lymphadenectomy on long‐term survival.

Methods

The data of 62 patients pathologically diagnosed with urachal carcinoma at Sun Yat‐sen University Cancer Center from 2002 to 2019 were retrospectively reviewed. Lymphadenectomy was defined as lymph nodes retrieved from the obturator, internal iliac, and external iliac lymph node stations. The Kaplan‐Meier method and Cox regression model were used to identify prognostic factors. OS and DFS were the primary endpoints.

Results

Of the 47 males and 15 females included, 54 patients underwent partial cystectomy, and 27 patients underwent lymphadenectomy. The number of patients with Sheldon stage IIIA, IIIB, IIIC, IVA, and IVB were 43 (69.4%), 4 (6.5%) 3 (4.8%), 6 (9.7%), and 6 (9.7%), respectively. The median DFS was 32.7 months, and the mean OS was 114.6 months. Sheldon stage (P < .001) and tumor size (P = .001) were identified as independent prognostic factors for DFS, whereas Sheldon stage (P = .003), peritoneal metastasis (P = .006), distant metastasis (P = .024), and recurrence in pelvic lymph nodes (P = .015) were independent prognostic factors for OS.

Conclusions

Urachal carcinoma has a high recurrence rate, but only peritoneal metastasis, distant metastasis, and recurrence in pelvic lymph nodes were found to be associated with OS. Lymphadenectomy was recommended because of its role in accurately staging the disease, and further research is needed to focus on lymphadenectomy and standardized the procedure.
Adding a late fall application of Proxy (ethephon) before two traditional spring applications improves seedhead control of annual bluegrass
Authors: Reicher Zachary J. , Sousek Matthew D. , Patton Aaron J. , Van Dyke Adam , Kreuser William C. , Inguagiato John C. , Miele Kevin M. , Brewer John , Askew Shawn D. , Hathaway Aaron , Nikolai Thomas A. , Kowalewski Alec , McDonald Brian
Published: April 2020

Annual bluegrass (ABG) (Poa annua L.) is a prolific seed producer in the spring on golf courses that in turn decreases aesthetic quality and trueness of ball roll on cool‐season putting greens. Proxy (ethephon) applied twice in the spring after green‐up is the current industry standard after the loss of Embark (mefluidide) from the turf and ornamental market. However, plant growth regulators including Proxy have been used for years to help suppress ABG seedheads with inconsistent success. The primary objective of this study was to determine if ABG seedhead suppression is improved by adding a late fall application of Proxy to the two traditional spring applications of plant growth regulators at nine locations with diverse environments. A second objective was to determine the importance of including Primo Maxx (trinexapac‐ethyl) in fall and spring applications. Adding a late fall application of Proxy prior to the two spring applications (F+S+S) improved control of ABG seedheads over the traditional two spring applications (S+S), but the magnitude of improvement varied among locations. When treatments were applied F+S+S, the industry standard tank mixture of Proxy + Primo Maxx provided consistent ABG seedhead control and turf quality, similar to Proxy + Fiata (phosphonate + proprietary pigment) and equal to or better than Proxy alone.