bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractDie 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

AbstractPactamycin 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

AbstractAn 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

AbstractA 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

AbstractAn 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

AbstractCationic 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

AbstractReducing 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

AbstractReported 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

AbstractTrisubstituted 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

AbstractHomoleptic 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

AbstractZero‐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.
Australian aid projects: What works, where projects work and how Australia compares
Authors: Wood Terence , Otor Sabit , Dornan Matthew 
Published: May 2020

AbstractIn 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

AbstractNovel 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

AbstractConjugated 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

AbstractThis 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

Abstract

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

AbstractThe 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

AbstractInvited 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

AbstractAdvanced 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.