bluuebunny/crossref_metadata_2025 huggingface dataset:
Infrared Spectrum of the Adamantane+–Water Cation: Hydration‐Induced C−H Bond Activation and Free Internal Water Rotation
Authors: George Martin Andreas Robert , Förstel Marko , Dopfer Otto
Published: May 2020

Diamondoid cations are reactive intermediates in their functionalization reactions in polar solution. Hydration is predicted to strongly activate their C−H bonds in initial proton abstraction reactions. To study the effects of microhydration on the properties of diamondoid cations, we characterize herein the prototypical monohydrated adamantane cation (C10H16+–H2O, Ad+–W) in its ground electronic state by infrared photodissociation spectroscopy in the CH and OH stretch ranges and dispersion‐corrected density functional theory (DFT) calculations. The water (W) ligand binds to the acidic CH group of Jahn–Teller distorted Ad+via a strong CH⋅⋅⋅O ionic H‐bond supported by charge–dipole forces. Although W further enhances the acidity of this CH group along with a proton shift toward the solvent, the proton remains with Ad+in the monohydrate. We infer essentially free internal W rotation from rotational fine structure of the ν3band of W, resulting from weak angular anisotropy of the Ad+–W potential.
Electrochemical Oxidative [4+2] Annulation for the π‐Extension of Unfunctionalized Heterobiaryl Compounds
Authors: Hu Xia , Nie Lei , Zhang Guoting , Lei Aiwen
Published: May 2020

Considering their unique electronic properties and diverse biological activities, regioselective access to fused aromatic compounds is significantly important in the field of organic materials and pharmaceutical science. Herein, we developed electrochemical oxidative [4+2] annulation reactions of heterobiaryl compounds with alkynes or alkenes, leading to the formation of several polycyclic heteroaromatic compounds. This electrosynthetic methodology serves for the straightforward π‐extension of unfunctionalized heterobiaryl compounds. The requirements of additional oxidants and prefunctionalization of starting materials are obviated. Through the in situ generation of heterobiaryl radical cation intermediates, various fused aromatic compounds were obtained with good yields and excellent regioselectivity.
Freisetzung von toxischem HCN bei der Stickoxidreduktion mittels NH3‐SCR in mager betriebenen Erdgasmotoren
Authors: Zengel Deniz , Koch Pirmin , Torkashvand Bentolhoda , Grunwaldt Jan‐Dierk , Casapu Maria , Deutschmann Olaf
Published: May 2020

Die Reduzierung der Emissionen von Treibhausgasen und gesundheitsgefährdenden Schadstoffen ist eines der wichtigsten Ziele unserer Industriegesellschaft. Erdgasmotoren sind insbesondere bei magerem Betrieb attraktiv, da sie weniger CO2 ausstoßen als Verbrennungsmotoren, die mit flüssigen Kraftstoffen betrieben werden. Sie benötigen allerdings ein katalytisches Kontrollsystem, um Stickoxide (NOx) aus dem Abgas zu entfernen. Hier haben wir das Zusammenspiel der aktuellen Technologie zur Stickoxidreduktion, die selektive katalytische Reduktion (SCR) mittels NH3, und Formaldehyd, einer schädlichen Emission in Erdgasmotoren, untersucht. Bei der NOx Entfernung werden beachtliche Mengen an toxischem Cyanwasserstoff (HCN) gebildet. Alle getesteten Katalysatoren wandeln Formaldehyd teilweise in HCOOH und CO um. Zusätzlich werden Sekundäremissionen von HCN über die katalytische Reaktion von Formaldehyd und dessen Oxidationsintermediaten mit NH3 beobachtet. Da die HCN Emissionen mit den derzeitigen Komponenten nicht effizient in schadstofffreie Gase umgewandelt werden können, ist die Entwicklung von Katalysatoren mit einer gesteigerten Oxidationsaktivität nötig, um dieses kritische Problem zu lösen.
Strategien für die Synthese von Pactamycin und Jogyamycin
Authors: Gerstner Nels C. , Nicastri Kate A. , Schomaker Jennifer M.
Published: May 2020

Pactamycin und Jogyamycin sind Aminocyclopentitol‐Naturstoffe, deren Kohlenstoffkern stereochemisch definierte Alkohol‐ oder Amineinheiten trägt. Aufgrund ihrer strukturellen Komplexität sowie der Vielfältigkeit der funktionellen Gruppen auf engem Raum sind sie faszinierende Syntheseziele. Pactamycin und dessen Derivate binden zur ribosomalen 30S‐Untereinheit und zeigen Wirkung gegen Parasiten, die arzneimittelresistente Malaria und afrikanische Schlafkrankheit verursachen; jedoch wird die Weiterentwicklung ihres therapeutischen Potenzials durch zelluläre Toxizität gebremst. Interessanterweise zeigen biotechnologisch erzeugte Analoga Unterschiede in der Selektivität und Toxizität in Säugerzellen, was die Entwicklung flexibler Strategien zur genauen Untersuchung der Struktur‐Wirkungs‐Beziehungen (SARs), insbesondere von Pactamycinanaloga ohne C7‐Hydroxygruppe, anspornt. In diesem Aufsatz werden Ansätze zur Synthese von Pactamycin und Jogyamycin gegenübergestellt, einschließlich zweier Totalsynthesen von Pactamycin. Wir diskutieren kurz die Bedeutung jeder Syntheseroute zu Analoga für die Untersuchung von SARs und die Entwicklung von Verbindungen mit erhöhter Selektivität für die Bindung an Ribosomen des Malariaerregers anstelle menschlicher Ribosomen.
Stereoselective Access to Fully Substituted Aldehyde‐Derived Silyl Enol Ethers by Iridium‐Catalyzed Alkene Isomerization
Authors: Massad Itai , Sommer Heiko , Marek Ilan
Published: May 2020

An in situ generated cationic Ir‐catalyst isomerizes simple allylic silyl ethers into valuable, fully substituted aldehyde‐derived silyl enol ethers. Importantly, by judicious choice of substrate, either of the two possible stereoisomers of a given enolate derivative is accessible with complete stereoselectivity. One‐pot isomerization‐aldol and isomerization‐allylation processes illustrate the synthetic utility of this method.
Photocatalytic α‐Tertiary Amine Synthesis via C−H Alkylation of Unmasked Primary Amines
Authors: Ryder Alison S. H. , Cunningham William B. , Ballantyne George , Mules Tom , Kinsella Anna G. , Turner‐Dore Jacob , Alder Catherine M. , Edwards Lee J. , McKay Blandine S. J. , Grayson Matthew N. , Cresswell Alexander J.
Published: May 2020

A practical, catalytic entry to α,α,α‐trisubstituted (α‐tertiary) primary amines by C−H functionalisation has long been recognised as a critical gap in the synthetic toolbox. We report a simple and scalable solution to this problem that does not require any in situ protection of the amino group and proceeds with 100 % atom‐economy. Our strategy, which uses an organic photocatalyst in combination with azide ion as a hydrogen atom transfer (HAT) catalyst, provides a direct synthesis of α‐tertiary amines, or their corresponding γ‐lactams. We anticipate that this methodology will inspire new retrosynthetic disconnections for substituted amine derivatives in organic synthesis, and particularly for challenging α‐tertiary primary amines.
Magnetic Micromotors for Multiple Motile Sperm Cells Capture, Transport, and Enzymatic Release
Authors: Xu Haifeng , Medina‐Sánchez Mariana , Schmidt Oliver G.
Published: May 2020

An integrated system combining a magnetically‐driven micromotor and a synthetized protein‐based hyaluronic acid (HA) microflake is presented for the in situ selection and transport of multiple motile sperm cells (ca. 50). The system appeals for targeted sperm delivery in the reproductive system to assist fertilization or to deliver drugs. The binding mechanism between the HA microflake and sperm relies on the interactions between HA and the corresponding sperm HA receptors. Once sperm are captured within the HA microflake, the assembly is trapped and transported by a magnetically‐driven helical microcarrier. The trapping of the sperm‐microflake occurs by a local vortex induced by the microcarrier during rotation‐translation under a rotating magnetic field. After transport, the microflake is enzymatically hydrolyzed by local proteases, allowing sperm to escape and finally reach the target location. This cargo‐delivery system represents a new concept to transport not only multiple motile sperm but also other actively moving biological cargoes.
A Layered Cationic Aluminum Oxyhydroxide as a Highly Efficient and Selective Trap for Heavy Metal Oxyanions
Authors: Bai Pu , Dong Zhuoya , Wang Shuang , Wang Xiangyu , Li Yue , Wang Yunzheng , Ma Yanhang , Yan Wenfu , Zou Xiaodong , Yu Jihong
Published: May 2020

Cationic framework materials, especially pure inorganic cationic frameworks that can efficiently and selectively capture harmful heavy metal oxyanions from aqueous solution are highly desired yet scarcely reported. Herein, we report the discovery of a 2D cationic aluminum oxyhydroxide, JU‐111, which sets a new benchmark for heavy metal oxyanion sorbents, especially for CrVI. Its structure was solved based on 3D electron diffraction tomography data. JU‐111 shows fast sorption kinetics (ca. 20 min), high capture capacity (105.4 mg g−1), and broad working pH range (3–10) toward CrVI oxyanions. Unlike layered double hydroxides (LDHs), which are poorly selective in the presence of CO32−, JU‐111 retains excellent selectivity for CrVI even under a large excess of CO32−. These superior features coupled with the ultra‐low cost and environmentally benign nature make JU‐111 a promising candidate for toxic metal oxyanion remediation as well as other potential applications.
Emission of Toxic HCN During NOx Removal by Ammonia SCR in the Exhaust of Lean‐Burn Natural Gas Engines
Authors: Zengel Deniz , Koch Pirmin , Torkashvand Bentolhoda , Grunwaldt Jan‐Dierk , Casapu Maria , Deutschmann Olaf
Published: May 2020

Reducing greenhouse gas and pollutant emissions is one of the most stringent priorities of our society to minimize their dramatic effects on health and environment. Natural gas (NG) engines, in particular at lean conditions, emit less CO2 in comparison to combustion engines operated with liquid fuels but NG engines still require emission control devices for NOx removal. Using state‐of‐the‐art technologies for selective catalytic reduction (SCR) of NOx with NH3, we evaluated the interplay of the reducing agent NH3 and formaldehyde, which is always present in the exhaust of NG engines. Our results show that a significant amount of highly toxic hydrogen cyanide (HCN) is formed. All catalysts tested partially convert formaldehyde to HCOOH and CO. Additionally, they form secondary emissions of HCN due to catalytic reactions of formaldehyde and its oxidation intermediates with NH3. With the present components of the exhaust gas aftertreatment system the HCN emissions are not efficiently converted to non‐polluting gases. The development of more advanced catalyst formulations with improved oxidation activity is mandatory to solve this novel critical issue.
Ambient Bistable Single Dipole Switching in a Molecular Monolayer
Authors: Cui Kang , Mali Kunal S. , Wu Dongqing , Feng Xinliang , Müllen Klaus , Walter Michael , De Feyter Steven , Mertens Stijn F. L.
Published: May 2020

Reported here is a molecular dipole that self‐assembles into highly ordered patterns at the liquid‐solid interface, and it can be switched at room temperature between a bright and a dark state at the single‐molecule level. Using a scanning tunneling microscope (STM) under suitable bias conditions, binary information can be written at a density of up to 41 Tb cm−2 (256 Tb/in2). The written information is stable during reading at room temperature, but it can also be erased at will, instantly, by proper choice of tunneling conditions. DFT calculations indicate that the contrast and switching mechanism originate from the stacking sequence of the molecular dipole, which is reoriented by the electric field between the tip and substrate.
Photochemical Deracemization of Allenes and Subsequent Chirality Transfer
Authors: Plaza Manuel , Jandl Christian , Bach Thorsten
Published: May 2020

Trisubstituted allenes with a 3‐(1′‐alkenylidene)‐pyrrolidin‐2‐one motif were successfully deracemized (13 examples, 86–98 % ee) employing visible light (λ=420 nm) and a chiral triplet sensitizer as the catalyst (2.5 mol %). The photocatalyst likely operates by selective recognition of one allene enantiomer via hydrogen bonds and by a triplet‐sensitized racemization process. Even a tetrasubstituted allene (45 % ee) and a seven‐membered 3‐(1′‐alkenylidene)‐azepan‐2‐one (62 % ee) could be enantiomerically enriched under the chosen conditions. It was shown that the axial chirality of the allenes can be converted into point chirality by a Diels–Alder (94–97 % ee) or a bromination reaction (91 % ee). Ring opening of the five‐membered pyrrolidin‐2‐one was achieved without significantly compromising the integrity of the chirality axis (92 % ee).
The Exceptional Diversity of Homoleptic Uranium–Methyl Complexes
Authors: Sears Jeffrey D. , Sergentu Dumitru‐Claudiu , Baker Tessa M. , Brennessel William W. , Autschbach Jochen , Neidig Michael L.
Published: May 2020

Homoleptic σ‐bonded uranium–alkyl complexes have been a synthetic target since the Manhattan Project. The current study describes the synthesis and characterization of several unprecedented uranium–methyl complexes. Amongst these complexes, the first example of a homoleptic uranium–alkyl dimer, [Li(THF)4]2[U2(CH3)10], as well as a seven‐coordinate uranium–methyl monomer, {Li(OEt2)Li(OEt2)2UMe7Li}n were both crystallographically identified. The diversity of complexes reported herein provides critical insight into the structural diversity, electronic structure and bonding in uranium–alkyl chemistry.
Multicomponent Organic Metal Halide Hybrid with White Emissions
Authors: Xu Liang‐Jin , Lee Sujin , Lin Xinsong , Ledbetter Logan , Worku Michael , Lin Haoran , Zhou Chenkun , Liu He , Plaviak Anna , Ma Biwu
Published: May 2020

Zero‐dimensional (0D) organic metal halide hybrids, in which organic and metal halide ions cocrystallize to form neutral species, are a promising platform for the development of multifunctional crystalline materials. Herein we report the design, synthesis, and characterization of a ternary 0D organic metal halide hybrid, (HMTA)4PbMn0.69Sn0.31Br8, in which the organic cation N‐benzylhexamethylenetetrammonium (HMTA+, C13H19N4+) cocrystallizes with PbBr42−, MnBr42−, and SnBr42−. The wide band gap of the organic cation and distinct optical characteristics of the three metal bromide anions enabled the single‐crystalline “host–guest” system to exhibit emissions from multiple “guest” metal halide species simultaneously. The combination of these emissions led to near‐perfect white emission with a photoluminescence quantum efficiency of around 73 %. Owing to distinct excitations of the three metal halide species, warm‐ to cool‐white emissions could be generated by controlling the excitation wavelength.
Synthesis of pyrazolopyrimidines in mild conditions by gold nanoparticles supported on magnetic ionic gelation in aqueous solution
Authors: Yu Lanlan , Xing Shilong , Zheng Kai , Sadeghzadeh Seyed Mohsen
Published: May 2020

In this study, novel magnetic nanoparticle (FeNi3) based gold NPs with high surface area and easy accessibility of active sites were successfully developed by a facile approach. FeNi3 was functionalized with ionic gelation (IG) groups acting as robust anchors so that the gold NPs were well dispersed on the FeNi3 without aggregation. Spirulina coating was carried out via a wet impregnation technique based on IG using tripolyphosphate as a cross‐linking agent. Because of the amplification effect of IG, high loading capacities were achieved for the nanocatalysts. Furthermore, FeNi3/IG/Au showed superparamagnetic properties, contributing to the easy recovery of the nanocatalysts by magnetic separation. FeNi3/IG/Au was developed for the synthesis of pyrazolopyrimidines in mild conditions. The FeNi3/IG/Au magnetic NPs were thoroughly characterized using transmission electron microscopy, field emission scanning electron microscopy, vibrating sample magnetometry, Fourier‐transform infrared spectroscopy, and thermogravimetric analysis. The FeNi3/IG/Au nanocatalyst showed high robustness and stability in reaction for up to five cycles without significant loss of activity, probably due to the high loading of IG in the catalyst.
Green synthesis of the 1‐substituted 1H‐1, 2, 3, 4‐tetrazoles over bifunctional catalyst based on copper intercalated into Mg/Al hydrotalcite modified magnetite nanoparticles
Authors: Salimi Mehri , Zamanpour Azadeh
Published: May 2020

An effective one‐pot, convenient process for the synthesis of 1‐ substituted 1H‐tetrazoles from triethyl orthoformate, amines, and sodium azide is described using copper (II) doped and immobilized on functionalized magnetic hydrotalcite (Fe3O4/HT‐NH2 CuII) as a novel recyclable catalyst. The application of this catalyst allows the synthesis of a variety of tetrazoles in good to excellent yields in water. The new catalyst was characterized using Fourier transform infrared (FT‐IR) spectroscopy, X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy (EDX), thermogravimetric analysis (TGA), vibration sample magnetometry (VSM) and inductively coupled plasma analysis (ICP‐OES). This new procedure offers several advantages such as short operational simplicity, practicability, and applicability to various substrates and the absence of any tedious workup or purification. The loading amount of CuII (doped and immobilized) on functionalized magnetic hydrotalcite was indicated to be 4.66 mmol g−1, obtained from the ICP‐OES analysis. Also, the excellent catalytic performance, thermal stability, and separation of the catalyst make it an excellent heterogeneous system and a useful alternative to other heterogeneous catalysts. Also, the catalyst could be magnetically separated and reused six times without significant loss of catalytic activity.
Australian aid projects: What works, where projects work and how Australia compares
Authors: Wood Terence , Otor Sabit , Dornan Matthew
Published: May 2020

In this article, we conduct the first‐ever systematic study of Australian aid project appraisals. Using a previously unstudied data set of appraisals, we study project and recipient country factors influencing Australian aid effectiveness. We find effectiveness varies more within recipient countries than between countries. We find larger projects are more likely to be successful. Humanitarian projects are more successful on average than development projects. We also find that Australian aid is less likely to succeed in the Pacific than elsewhere, a significant finding given Australia's increased focus on the region. Finally, we show that Australia does not appear to be an unusual donor: when we compare Australia with other donors in a global data set, we find similar variables are correlated with effectiveness for most donors, including Australia.
Synthesis and biological evaluation of Val–Val dipeptide–sulfonamide conjugates
Authors: Ezugwu James A. , Okoro Uchechukwu C. , Ezeokonkwo Mercy A. , Bhimapaka Chinaraju , Okafor Sunday N. , Ugwu David I. , Ugwuja Daniel I.
Published: May 2020

Novel Val–Val dipeptide–benzenesulfonamide conjugates were reported in this study. These were achieved by a condensation reaction of p‐substituted benzenesulfonamoyl alkanamides with 2‐amino‐4‐methyl‐N‐substituted phenyl butanamide using classical peptide‐coupling reagents. The compounds were characterized using Fourier transform infrared, 1H‐nuclear magnetic resonance (NMR), 13C‐NMR, and electrospray ionization–high‐resolution mass spectrometry spectroscopic techniques. As predicted from in silico studies, the Val–Val dipeptide–benzenesulfonamide conjugates exhibited antimalarial and antioxidant properties that were analogous to the standard drug. The synthesized compounds were evaluated for in vivo antimalarial activity against Plasmodium berghei. The hematological analysis was also conducted on the synthesized compounds. At 50 mg/kg body weight, compounds 8a, 8d, and 8g–i inhibited the multiplication of the parasite by 48–54% on Day 7 of posttreatment exposure, compared with the 67% reduction with artemisinin. All the synthesized dipeptides had a good antioxidant property, but it was less when compared with vitamin C. The dipeptides reported herein showed the ability to reduce oxidative stress arising from the malaria parasite.
Metal Phthalocyanine‐Porphyrin‐based Conjugated Microporous Polymer‐derived Bifunctional Electrocatalysts for Zn‐Air Batteries
Authors: Li Yan , Tao Xisheng , Wei Juncheng , Lv Xiaoling , Wang Heng‐Guo
Published: May 2020

Conjugated microporous polymers (CMPs) as emerging porous materials with diverse structures and tunable building‐units have attracted much attention in the electrochemical field. Herein, we designed phthalocyanine‐porphyrin‐based conjugated microporous polymers as precursors for fabrication of Co, Fe, N tri‐doped graphene composites towards oxygen reduction and evolution reaction (ORR/OER). As expected, the elements cobalt and iron are well dispersed in graphene carbon and interact with the nitrogen sites, thereby providing extra electrocatalytic active sites and enhancing its overall conductivity. Benefiting from its unique design and structure, the obtained catalyst affords a superior bifunctional catalytic activity with a positive onset potential of 0.957 V for ORR, and a low overpotential of 0.36 V for OER. More attractively, the CoFeNG is employed as an air cathode catalyst in Zn‐air batteries, showing a maximum current density of 215 mA cm−2 and good cycle stability for 20000 s. The rational design of phthalocyanine‐porphyrin‐based derivatives provides a feasible route for the construction of high‐performance ORR/OER catalysts.
Extreme precipitation events are becoming less frequent but more intense over Jeddah, Saudi Arabia. Are shifting weather regimes the cause?
Authors: Luong Thang M. , Dasari Hari P. , Hoteit Ibrahim
Published: May 2020

This study analyses the connection between extreme rainfall events in Jeddah, Saudi Arabia, and synoptic‐scale weather patterns over the Arabian Peninsula. Mean rainfall follows a decreasing trend; however, the number of rainy days has increased. Interestingly, extreme rainfall is becoming less frequent but shows an increased intensity. Here we utilize self‐organizing maps (SOMs) to identify the weather patterns of the most intense rainy days and the synoptic systems causing extreme rainfall in the Jeddah region. Three main weather patterns that cause heavy rainfall events over Jeddah during the cooler months (November–April) are identified, all reflect tropical‐extratropical interactions. Extreme events in the early period (1979–1998) are characterized by a stronger tropical influence and local precipitation patterns, while a stronger extratropical forcing and higher extreme rainfall amounts are spotted in the late period (1999–2018). Our results suggest that in recent decades, the mechanism causing extreme rainfall over the city of Jeddah has shifted toward a weather regime with stronger extratropical influence.
Mortality from abdominal aortic aneurysm: trends in European Union 15+ countries from 1990 to 2017
Authors: Al-Balah A , Goodall R , Salciccioli J D , Marshall D C , Shalhoub J
Published: May 2020

Background

This observational study assessed trends in abdominal aortic aneurysm (AAA) death rates in European Union (EU) 15+ countries for the years 1990 to 2017.

Methods

Age-standardized death rates (ASDRs) were extracted from the Global Burden of Disease Study Global Health Data Exchange. Trends were analysed using joinpoint regression analysis.

Results

Between 1990 and 2017, ASDRs from AAA decreased in all 19 EU15+ countries for women, and in 18 of 19 countries for men. Increasing AAA mortality was observed only for men in Greece (+5·3 per cent). The largest relative decreases in ASDR between 1990 and 2017 were observed in Australia (men –65·6 per cent, women –50·4 per cent) and Canada (men –60·8 per cent, women –48·6 per cent). Over the 28-year interval, the smallest decreases in ASDR for women were noted in Greece (–2·3 per cent) and in Italy (–2·5 per cent). In 2017, the highest mortality rates were observed in the UK for both men and women (7·5 per 100 000 and 3·7 per 100 000 respectively). The lowest ASDR was observed in Portugal for men (2·8 per 100 000) and in Spain for women (1·0 per 100 000). ASDRs for AAA in 2017 were higher for men than women in all 19 EU15+ countries. The most recent trends demonstrated increasing AAA ASDRs in 14 of 19 countries for both sexes; the increases were relatively small compared with the improvements in the preceding years.

Conclusion

This observational study identified decreasing mortality from AAA across EU15+ countries since 1990. The most recent trends demonstrated relatively small increases in AAA mortality across the majority of EU15+ countries since 2012.
Highly Durable Passive Direct Methanol Fuel Cell with Three‐Dimensional Ordered Porous NiCo2O4 as Cathode Catalyst
Authors: Fang Yuan , Qi Ji , Wang Fen , Hao Yaorui , Zhu Jianfeng , Zhang Pei
Published: May 2020

The performance of durability in direct methanol fuel cell (DMFC) is of great significance. In this study, NiCo2O4 with three‐dimensional ordered hierarchical pore was applied as oxygen reduction reaction electrocatalyst to enhance the long‐term stability in passive DMFC. The peak power densities of NiCo2O4‐based DMFC were 14.78 and 26 mW cm−2 at 15 and 40 °C, respectively. In the durability test, NiCo2O4‐based DMFC could operate continually for 1406 hours, which is approximately 6 times higher than the highest values reported in literature. And the outstanding durability could be mainly ascribed to the interconnected and ordered macropores channel in NiCo2O4, which could act as a structural buffer to mitigate the structural changes in porous nano‐catalysts, and also significantly facilitate the mass transport and the rapid elimination of cathodic product to solve the problem of “water flooding” at the cathode.
Structure‐Guided Design of a Group B Streptococcus Type III Synthetic Glycan–Conjugate Vaccine
Authors: Oldrini Davide , del Bino Linda , Arda Ana , Carboni Filippo , Henriques Pedro , Angiolini Francesca , Quintana Jon I. , Calloni Ilaria , Romano Maria R. , Berti Francesco , Jimenez‐Barbero Jesus , Margarit Immaculada , Adamo Roberto
Published: May 2020

Invited for the cover of this issue is the group of Roberto Adamo at GlaxoSmithKline Research Center, Siena, and colleagues at The University of the Basque Country and Basque Research Technology Alliance. The image depicts a tactical plan with the different elements of the research as part of the team. Read the full text of the article at 10.1002/chem.202000284.
Nonlinear Optimization Strategies for Process Separations and Process Intensification
Authors: Biegler Lorenz T.
Published: May 2020

Advanced nonlinear programming (NLP) strategies based on equation‐oriented (EO) process models are leading to significant improvements in computer‐aided process engineering. The EO paradigm allows the development of large, integrated optimization platforms that expand the scope of continuous optimization tasks in process engineering. In particular, these platforms deploy significantly faster NLP strategies than in commercial simulation tools. Moreover, they exploit exact derivatives and system structure in order to consider much larger and more challenging systems. Finally, they allow the incorporation of much more general models, such as multi‐level optimization and complementarity constraints. For process optimization this allows the treatment of extended models for complex phase equilibrium and process separations. These advances facilitate the optimization of novel integrated systems that arise in process intensification. Several separation case studies are presented that illustrate these optimization concepts and demonstrate their effectiveness for hybrid membrane/distillation separations and reactive distillation systems that typify novel systems in process intensification.
Combined CCNE1 high‐level amplification and overexpression is associated with unfavourable outcome in tubo‐ovarian high‐grade serous carcinoma
Authors: Chan Angela MY , Enwere Emeka , McIntyre John B , Wilson Holly , Nwaroh Chidera , Wiebe Nicholas , Ou Young , Liu Shuhong , Wiedemeyer Katharina , Rambau Peter F , Grevers Xin , Morris Donald G , Neri Paola , Gilks C Blake , Visser Frank , Le Nhu , Luo Li , Cook Linda S , Köbel Martin
Published: May 2020

CCNE1 amplification is a recurrent alteration associated with unfavourable outcome in tubo‐ovarian high‐grade serous carcinoma (HGSC). We aimed to investigate whether immunohistochemistry (IHC) can be used to identify CCNE1 amplification status and to validate whether CCNE1 high‐level amplification and overexpression are prognostic in HGSC. A testing set of 528 HGSC samples stained with two optimised IHC assays (clones EP126 and HE12) was subjected to digital image analysis and visual scoring. DNA and RNA chromogenic in situ hybridisation for CCNE1 were performed. IHC cut‐off was determined by receiver operating characteristics (ROC). Survival analyses (endpoint ovarian cancer specific survival) were performed and validated in an independent validation set of 764 HGSC. Finally, combined amplification/expression status was evaluated in cases with complete data (n = 1114). CCNE1 high‐level amplification was present in 11.2% of patients in the testing set and 10.2% in the combined cohort. The optimal cut‐off for IHC to predict CCNE1 high‐level amplification was 60% positive tumour cells with at least 5% strong staining cells (sensitivity 81.6%, specificity 77.4%). CCNE1 high‐level amplification and overexpression were associated with survival in the testing and validation set. Combined CCNE1 high‐level amplification and overexpression was present in 8.3% of patients, mutually exclusive to germline BRCA1/2 mutation and significantly associated with a higher risk of death in multivariate analysis adjusted for age, stage and cohort (hazard ratio = 1.78, 95 CI% 1.38–2.26, p < 0.0001). CCNE1 high‐level amplification combined with overexpression identifies patients with a sufficiently poor prognosis that treatment alternatives are urgently needed. Given that this combination is mutually exclusive to BRCA1/2 germline mutations, a predictive marker for PARP inhibition, CCNE1 high‐level amplification combined with overexpression may serve as a negative predictive test for sensitivity to PARP inhibitors.
Design, Synthesis, Structure‐Activity Relationship and Docking Studies of Novel Functionalized Arylvinyl‐1,2,4‐Trioxanes as Potent Antiplasmodial as well as Anticancer Agents
Authors: Tiwari Mohit K. , Coghi Paolo , Agrawal Prakhar , Shyamlal Bharti Rajesh K. , Jun Yang Li , Yadav Lalit , Peng Yuzhong , Sharma Richa , Yadav Dharmendra K. , Sahal Dinkar , Kam Wai Wong Vincent , Chaudhary Sandeep
Published: May 2020

A novel series of synthetic functionalized arylvinyl‐1,2,4‐trioxanes (8 a–p) has been prepared and assessed for their in vitro antiplasmodial activity against the chloroquine‐resistant Pf INDO strain of Plasmodium falciparum by using a SYBR green‐I fluorescence assay. Compounds 8 g (IC50=0.051 μM; SI=589.41) and 8 m (IC50=0.059 μM; SI=55.93) showed 11‐fold and >9‐fold more potent antiplasmodial activity, respectively, as compared to chloroquine (IC50=0.546 μM; SI=36.63). Different in silico docking studies performed on many target proteins revealed that the most active arylvinyl‐1,2,4‐trioxanes (8 g and 8 m) showed dihydrofolate reductase (DHFR) binding affinities on a par with those of chloroquine and artesunate. The in vitro cytotoxic potentials of 8 a–p were also evaluated against human lung (A549) and liver (HepG2) cancer cell lines along with immortalized normal lung (BEAS‐2B) and liver (LO2) cell lines. Following screening, five derivatives viz. 8 a, 8 h, 8 l, 8 m and 8 o (IC50=1.65–31.7 μM; SI=1.08–10.96) were found to show potent cytotoxic activity against (A549) lung cancer cell lines, with selectivity superior to that of the reference compounds artemisinin (IC50=100 μM), chloroquine (IC50=100 μM) and artesunic acid (IC50=9.85 μM; SI=0.76). In fact, the most active 4‐naphthyl‐substituted analogue 8 l (IC50=1.65 μM; SI >10) exhibited >60 times more cytotoxicity than the standard reference, artemisinin, against A549 lung cancer cell lines. In silico docking studies of the most active anticancer compounds, 8 l and 8 m, against EGFR were found to validate the wet lab results. In summary, a new series of functionalized aryl‐vinyl‐1,2,4‐trioxanes (8 a–p) has been shown to display dual potency as promising antiplasmodial and anticancer agents.
A Library of Thiazolidin‐4‐one Derivatives as Protein Tyrosine Phosphatase 1B (PTP1B) Inhibitors: An Attempt To Discover Novel Antidiabetic Agents
Authors: Patel Ashish D. , Pasha Thopallada Y. , Lunagariya Paras , Shah Umang , Bhambharoliya Tushar , Tripathi Rati K. P.
Published: May 2020

Protein tyrosine phosphatase 1B (PTP1B) is an important target for the treatment of diabetes. A series of thiazolidin‐4‐one derivatives 8–22 was designed, synthesized and investigated as PTP1B inhibitors. The new molecules inhibited PTP1B with IC50 values in the micromolar range. 5‐(Furan‐2‐ylmethylene)‐2‐(4‐nitrophenylimino)thiazolidin‐4‐one (17) exhibited potency with a competitive type of enzyme inhibition. structure–activity relationship studies revealed various structural facets important for the potency of these analogues. The findings revealed a requirement for a nitro group‐including hydrophobic heteroaryl ring for PTP1B inhibition. Molecular docking studies afforded good correlation with experimental results. H‐bonding and π–π interactions were responsible for optimal binding and effective stabilization of virtual protein‐ligand complexes. Furthermore, in‐silico pharmacokinetic properties of test compounds predicted their drug‐like characteristics for potential oral use as antidiabetic agents.Additionally, a binding site model demonstrating crucial pharmacophoric characteristics influencing potency and binding affinity of inhibitors has been proposed, which can be employed in the design of future potential PTP1B inhibitors.
Pharmacokinetic Parameters of HIV‐1 Protease Inhibitors
Authors: Nascimento André L. C. S. , Fernandes Richard P. , Quijia Christian , Araujo Victor H. S. , Pereira Juliana , Garcia Jerusa S. , Trevisan Marcello G. , Chorilli Marlus
Published: May 2020

Since the beginning of the HIV epidemic, research has been carried out to control the virus. Understanding the mechanisms of replication has given access to the various classes of drugs that over time have transformed AIDS into a manageable chronic disease. The class of protease inhibitors (PIs) gained notice in anti‐retroviral therapy, once it was found that peptidomimetic molecules act by blocking the active catalytic center of the aspartic protease, which is directly related to HIV maturation. However, mutations in enzymatic internal residues are the biggest issue for these drugs, because a small change in biochemical interaction can generate resistance. Low plasma concentrations of PIs favor viral natural selection; high concentrations can inhibit even partially resistant enzymes. Food‐drug/drug‐drug interactions can decrease the bioavailability of PIs and are related to many side effects. Therefore, this review summarizes the pharmacokinetic properties of current PIs, the changes when pharmacological boosters are used and also lists the major mutations to help understanding of how long the continuous treatment can ensure a low viral load in patients.
Design, Synthesis, and Characterization of Novel CXCR4 Antagonists Featuring Cyclic Amines
Authors: Lin Yu , Li Zhanhui , Ma Haikuo , Wang Yujie , Wang Xu , Song Shiwei , Zhao Li , Wu Shuwei , Tian Sheng , Fu Chunyan , Luo Lusong , Zhu Fang , He Sudan , Zheng Jiyue , Zhang Xiaohu
Published: May 2020

Chemokine receptor CXCR4 and its natural ligand CXCL12 (also known as stromal cell‐derived factor‐1, or SDF‐1) regulate a broad range of physiological functions. Dysregulation of the CXCL12/CXCR4 axis is involved in numerous pathological conditions such as HIV infection, inflammation and cancer. Herein, we report the design, synthesis, and characterization of novel CXCR4 antagonists based on cyclic amine scaffolds. Compound 24 was identified as a potent CXCR4 receptor antagonist (competitive inhibition of 12G5 binding, IC50=24 nM; functional inhibition of CXCL12‐induced cytosolic calcium increase, IC50=0.1 nM). In addition, compound 24 potently inhibited cell migration in CXCR4/CXCL12‐mediated chemotaxis in a matrigel invasion assay. The absolute configuration of compound 24 was elucidated by X‐ray crystallography.
Manipulating the strength of organism–environment feedback increases nonlinearity and apparent hysteresis of ecosystem response to environmental change
Authors: Garnier Aurélie , Hulot Florence D. , Petchey Owen L.
Published: May 2020

Theory predicts that organism–environment feedbacks play a central role in how ecological communities respond to environmental change. Strong feedback causes greater nonlinearity between environmental change and ecosystem state, increases the likelihood of hysteresis in response to environmental change, and augments the possibility of alternative stable regimes. To illustrate these predictions and their dependence on a temporal scale, we simulated a minimal ecosystem model. To test the predictions, we manipulated the feedback strength between the metabolism and the dissolved oxygen concentration in an aquatic heterotrophic tri‐trophic community in microecosystems. The manipulation consisted of five levels, ranging from low to high feedback strength by altering the oxygen diffusivity: free gas exchange between the microcosm atmosphere and the external air (metabolism not strongly affecting environmental oxygen), with the regular addition of 200, 100, or 50 ml of air and no gas exchange. To test for nonlinearity and hysteresis in response to environmental change, all microecosystems experienced a gradual temperature increase from 15 to 25°C and then back to 15°C. We regularly measured the dissolved oxygen concentration, total biomass, and species abundance. Nonlinearity and hysteresis were higher in treatments with stronger organism–environment feedbacks. There was no evidence that stronger feedback increased the number of observed ecosystem states. These empirical results are in broad agreement with the theory that stronger feedback increases nonlinearity and hysteresis. They therefore represent one of the first direct empirical tests of the importance of feedback strength. However, we discuss several limitations of the study, which weaken confidence in this interpretation. Research demonstrating the causal effects of feedback strength on ecosystem responses to environmental change should be placed at the core of efforts to plan for sustainable ecosystems.
Enzootic maintenance of sylvatic plague in Canada's threatened black‐tailed prairie dog ecosystem
Authors: Liccioli Stefano , Stephens Tara , Wilson Sian C. , McPherson Jana M. , Keating Laura M. , Antonation Kym S. , Bollinger Trent K. , Corbett Cindi R. , Gummer David L. , Lindsay L. Robbin , Galloway Terry D. , Shury Todd K. , Moehrenschlager Axel
Published: May 2020

Data paucity can seem to hinder science‐based approaches to the conservation of imperiled species. Yet, even individually limited datasets can improve understanding and management of complex ecological systems when carefully integrated. We demonstrate this approach to gain first insights on the transmission ecology of Yersinia pestis in Grasslands National Park (GNP), Canada, where both the bacterium and its rodent host, the nationally threatened black‐tailed prairie dog (BTPD, Cynomys ludovicianus), reach the northern limit of their distribution in North America. Primarily flea‐borne, Y. pestis causes sylvatic plague, a disease of exceptional relevance to both human health and wildlife conservation. We integrated data collected independently by multiple organizations in 2010–2017 across 17 BTPD colonies, where the species co‐occur with Richardson's ground squirrels (RGS, Urocitellus richardsonii). Available data included estimates of BTPD density and occupancy from visual counts and colony mapping; information on flea distribution, abundance, and prevalence of infection with Y. pestis from burrow swabbing, animal combing, and PCR assays; and the response of these variables to deltamethrin application on BTPD colony sections. Our analyses suggest that sylvatic plague in GNP is maintained at an enzootic level (i.e., chronic presence affecting a low proportion of individuals) with no evidence of widespread mortality, at least partially due to reduced flea activity after spring (percentage of prevalence in burrows: April–May = 11.69–33.89%; June–September: 1.75–3.19%), low prevalence of Y. pestis in flea samples (95% CI = 0.42–2.27%), and relatively low BTPD densities. Nonetheless, reducing flea prevalence through insecticide application had a positive effect on BTPD abundance, suggesting that enzootic plague is causing chronic mortality. Because flea prevalence on hosts was higher following drier years and higher on RGS than on BTPD (26.69% vs. 3.27%), insecticide application may be particularly important during dry periods and may need to take RGS and their movements into consideration. Differences between flea communities sampled by burrow swabbing and host combing suggest that plague surveillance should integrate both methods. Effects of projected climate change on vector life cycles, flea community composition, and host–parasite interactions warrant continued monitoring and an adaptive approach to species recovery actions and plague mitigation measures.
On the Reactivity of Thiourea Derivatives with Silver(I) Oxide
Authors: Pilz Sarah K. , Mohr Fabian
Published: May 2020

Aryl thioureas of the type ArNHC(S)NR2 react with Ag2O to form the corresponding silver(I) thioureato complexes. Depending on the nature of the thiourea, either insoluble materials, zig‐zag coordination polymers or discrete tetranuclear silver species were isolated and structurally characterised. These thioureato complexes react with one, two or three equivalents of a phosphine ligand, forming a series of compounds with various structural motifs and different coordination numbers at the metal. The spectroscopic properties and structures of several of these compounds are discussed.
Genetic instability assessed by telomere length and micronucleus in physicians exposed to anesthetics
Authors: Braz Mariana G. , Silva Mariane A. P. , Figueiredo Drielle B. S. , Aun Aline G. , Marques Lais S. K. , Lara Juliana R. , Braz Leandro G.
Published: May 2020

This study evaluated both telomere length (TL) and micronucleus (MN) as indicators of genome instability in 40 anesthesiologists occupationally exposed to anesthetics and in 40 physicians without occupational exposure to anesthetics who were matched by age, sex, and lifestyle. Blood and buccal samples were collected from both groups at the same period. Anesthetic exposure assessment was performed. The studied groups were assessed regarding relative TL by quantitative polymerase chain reaction and MN by buccal MN assay. Mean trace concentrations of anesthetics were below two parts per million. No significant differences between groups were found for both biomarkers. However, MN frequency was slightly increased (1.9‐fold; p = .094) in the exposed group compared to the control group and in the exposed males (2.4‐fold; p = .090) compared to unexposed males. TL and age showed a significant negative correlation. Anesthetic occupational exposure below recommended levels is not associated with changes in TL and MN in anesthesiologists.
Organic Amines as Targeting Stabilizer at the Polymer/Fullerene Interface for Polymer:PC61BM Solar Cells
Authors: Li Zerui , Yan Lingpeng , Shan Jiankai , Gu Huimin , Lin Yi , Wang Yaling , Tan Hongwei , Ma Chang-Qi
Published: May 2020

Herein, it is demonstrated that a small amount (0.05% in weight ratio) of polyethyleneimine (PEI) can effectively suppress the “burn‐in” degradation of both PTB7‐Th:PC61BM and P3HT:PC61BM cells, similar to the piperazine derivatives, suggesting that organic amines can serve as universal stabilizer in polymer:PC61BM solar cells. Light‐induced electron spin resonance (LESR) spectroscopy measurement shows a higher ESR signal intensity of PC61BM anions in 0.2% PEI‐doped film than in 1% piperazine‐doped film. Moreover, no piperazine is detected in a 10% (w/w) piperazine‐doped film by gas chromatography–mass spectrometry (GSMS). These results suggest that the residual piperazine in the blend film is very low, which can be understood by the high volatility of piperazine. Quantum calculations are performed on the intermolecular binding energy (EB) between polymer (using model repeating units), PC61BM, and piperazine molecules. Results reveal that piperazine prefers to localize at the polymer:fullerene interface by complexing with PC61BM (in P3HT:PC61BM) or PTB7‐Th (in PTB7‐Th:PC61BM system), which indicates that the photo dimerization of PC61BM which causes the “burn‐in” degradation of polymer:fullerene solar cells mainly happens at the donor/acceptor interface, and the organic amine serves as the targeting stabilizer at the interface.
Are farmers using cropping system intensification technologies experiencing poverty reduction in the Great Lakes Region of Africa?
Authors: Dontsop Nguezet Paul Martin , Ainembabazi John Herbert , Alene Arega , Abdulaye Tahirou , Feleke Shiferaw , Nziguheba Generose , Khonje Makaiko , Mignouna Djana , Okafor Christopher , Njukwe Emmanuel , Van Asten Piet , Mapatano Sylvain , Vanlauwe Bernard , Manyong Victor
Published: May 2020

This study evaluated the poverty reduction impact of the adoption of cropping system intensification (CSI) technologies using the endogenous switching regression (ESR) model in the Great Lakes region of Africa that comprises Burundi, eastern DR Congo, and Rwanda. The study data came from a household survey of 1,495 sample households interviewed between October and December 2014. Results indicated that the adoption of the CSI technologies had increased crop yield, crop income, and per capita consumption expenditure in the region, resulting in poverty reduction. Among the three countries, eastern DR Congo witnessed the highest poverty reduction (13% points) followed by Rwanda (6% points) and Burundi (2% points). Considering the adoption rate and size of the target population in each country at baseline, an estimated 180 thousand poor individuals had escaped poverty due to the adoption of the CSI technologies. This presents important evidence in favor of promoting CSI technologies as part of poverty reduction strategy. Given the large population size that remains poor even after adoption, we suggest that research‐based poverty reduction strategies such as the CSI technologies should be complemented with development interventions.
Trader networks and options risk management
Authors: Boyd Naomi , Locke Peter , Sun Li
Published: May 2020

We examine the effect of trading partner concentration and a matrix of variables which dictate the relative importance of a trader to the network on a set of large member proprietary traders’ risk. An increased closeness centrality and concentration of trading among network partners are found to reduce price, volatility and rebalancing risk. We further explore the nature of trading concentration established through traders’ recurring trading relationships to find that trading with an established and small network has a positive, yet costly, effect on inventory management. Relationships among market makers are important to managing their portfolio of risk.