bluuebunny/crossref_metadata_2025 huggingface dataset:
Regime geocryological observations of the high altitude mountain passes of Tien Shan
Authors: Zheltenkova Nadezhda Valer'evna , Gagarin Vladimir Evgen'evich , Koshurnikov Andrei Viktorovich , Nabiev Islom Abdudzhaborovich
Published: October 2020

This article examines the questions of assessment of the state and dynamics of frozen rocks in the conditions of changing climate on the territory of Tien Shan. The consists in evaluation of geocryological conditions of frozen rocks in Northern and South-Western Tien Shan regions in accordance with the data of regime observations conducted by authors on the equipped stationary sites of high altitude mountain passes. The article provides the results of a set of methods of geocryological and geophysical research, including drilling of engineering-geocryological wells with sampling and determination of the structure and composition of soils, thermometry in wells, geophysical profiling with construction of geoelectric sections. The proposed set of geophysical methods allows stratifying the section, obtain the boundaries of thawed and frozen rocks, as well as follow the dynamics of dangerous cryogenic processes. The geophysical TEM method for work in the mountains features a number of advantages –  the absence of galvanic grounding, mobility of installation, determination in addition to the characteristics of the rock resistance, polarization, the high values of which (according to laboratory data) indicate the presence of ice. The importance of direct observations and geocryological monitoring is emphasized, since in the zones of proliferation of high altitude permafrost, climate warming can lead to the activation of catastrophic processes such as mudflows, outbursts of glacial mountain lakes, landslides, thermal erosion, and thermokarst. Therefore, constant monitoring of the glacial zone is necessary for determination of the new and assessment of the state of the existing foci of hazardous exogenous geological processes. 
Proposed Mechanism of Action of Topically Applied Autologous Blood Clot Tissue
Authors: Snyder Robert J. , Schultz Gregroy , Wachuku Chinenye , Rashid Arij M. , Ead Joey Karim
Published: October 2020

Background: Chronic wounds, especially in patients with diabetes, often represent clinical challenges. Recently, the use of a topically applied blood clot has garnered significant interest. This stromal matrix contains viable cells that are autologous, biocompatible, biological, and consistent with a metabolically active scaffold. It has been shown to be safe, effective, and cost-efficient. However, the mechanism of action of this modality remains elusive. We sought to identify a potential mechanism of action of an autologous blood clot.

Methods: Review of clinical and scientific literature hypothesizes on how autologous blood clots may stimulate healing and facilitate the movement of critical substrates while lowering bioburden and fostering angiogenesis.

Results: Blood serves as a carrier for many components: red blood cells, white blood cells, platelets, proteins, clotting factors, minerals, electrolytes, and dissolved gasses. In response to tissue injury, the hemostatic mechanism uses a host of vascular and extravascular responses initiating primary, secondary, and tertiary hemostasis. The scaffold created by the autologous blood clot tissue provides a medium in which the body can transform the wound from a nonhealing chronic condition into a healing acute condition. The autologous blood clot tissue also creates a protective setting for the body to use its own mechanisms to promote wound healing in an organized manner. This transient scaffold recruits surrounding fibroblasts and promotes cell ingrowth to foster granulation tissue remodeling. Cells in this matrix sense not only soluble factors but also their physical environments. This well-orchestrated mechanism includes signals from soluble molecules, from the substrate/matrix to which the cell is adherent, from the mechanical or physical forces acting on it, and from contact with other cells. Topically applied autologous blood clot tissue can lower bacterial bioburden while stimulating angiogenesis and fostering the movement of keratinocytes and fibroblasts.

Conclusions: Topically applied autologous blood clot tissue is a formidable cellular and tissue-based therapy that has been shown to be safe and effective. Although the central component of this therapy is blood, the autologous clot tissue creates a scaffold that performs as a biological delivery system that functions to control the release of growth factors and cytokines over several days.
Repairing Infrastructures
Authors: Henke Christopher R. , Sims Benjamin
Published: October 2020

An investigation of the causes and consequences of the strange, ambivalent, and increasingly central role of infrastructure repair in modern life.

Infrastructures—communication, food, transportation, energy, and information—are all around us, and their enduring function and influence depend on the constant work of repair. In this book, Christopher Henke and Benjamin Sims explore the causes and consequences of the strange, ambivalent, and increasingly central role of infrastructure repair in modern life. Henke and Sims offer examples, from local to global, to investigate not only the role of repair in maintaining infrastructures themselves but also the social and political orders that are created and sustained through them. Repair can encompass not only the kind of work we most commonly associate with the term but also any set of practices aimed at restoring a sense of normalcy or credibility to the places and institutions we inhabit in everyday life.

From cases as diverse as the repair of building systems on a university campus, a conflict over retrofitting a bridge while protecting murals painted on it, and the global challenge posed by climate change, Henke and Sims assemble a range of examples to illustrate key conceptual points about the role of repair. They show that repair is an essential if often overlooked aspect of understanding the broader impact and politics of infrastructures. Understanding repair helps us better understand infrastructures and the scope of their influence on our lives.

The open access edition of this book was made possible by generous funding from Arcadia – a charitable fund of Lisbet Rausing and Peter Baldwin.
Free-to-Play
Authors: Paul Christopher A.
Published: October 2020

An examination of free-to-play and mobile games that traces what is valued and what is marginalized in discussions of games

Free-to-play and mobile video games are an important and growing part of the video game industry, and yet they are often disparaged by journalists, designers, and players and pronounced inferior to games with more traditional payment models. In this book, Christopher Paul shows that underlying the criticism is a bias against these games that stems more from who is making and playing them than how they are monetized. Free-to-play and mobile games appeal to different kinds of players, many of whom are women and many of whom prefer different genres of games than multi-level action-oriented killing fests. It's not a coincidence that some of the few free-to-play games that have been praised by games journalists are League of Legends and World of Tanks.

Paul explains that free-to-play games have a long history, and that the current model of premium sales is an aberration. He analyzes three monetization strategies: requirements to spend, where players must make a purchase to gain access; paying for advantage; and optional spending (used by Fortnite, among other popular free-to-play games). He considers how players rationalize or resist spending; discusses sports games and gacha-style games that entice players to make “just one more” purchase; and describes the framing of certain free-to-play games as proper games while others are cast as abusive abominations. Paul's analysis offers a provocative picture of what is valued and what is marginalized in discussions of games.
Quantile-dependent expressivity of plasma adiponectin concentrations may explain its sex-specific heritability, gene-environment interactions, and genotype-specific response to postprandial lipemia
Authors: Williams Paul T.
Published: October 2020

Background

“Quantile-dependent expressivity” occurs when the effect size of a genetic variant depends upon whether the phenotype (e.g. adiponectin) is high or low relative to its distribution. We have previously shown that the heritability (h2) of adiposity, lipoproteins, postprandial lipemia, pulmonary function, and coffee and alcohol consumption are quantile-specific. Whether adiponectin heritability is quantile specific remains to be determined.

Methods

Plasma adiponectin concentrations from 4,182 offspring-parent pairs and 1,662 sibships from the Framingham Heart Study were analyzed. Quantile-specific heritability from offspring-parent (βOP,h2 = 2βOP/(1 + rspouse)) and full-sib regression slopes (βFS, h2 = {(1 + 8rspouseβFS)0.05-1}/(2rspouse)) were robustly estimated by quantile regression with nonparametric significance assigned from 1,000 bootstrap samples.

Results

Quantile-specific h2 (± SE) increased with increasing percentiles of the offspring’s age- and sex-adjusted adiponectin distribution when estimated from βOP (Ptrend = 2.2 × 10−6): 0.30 ± 0.03 at the 10th, 0.33 ± 0.04 at the 25th, 0.43 ± 0.04 at the 50th, 0.55 ± 0.05 at the 75th, and 0.57 ± 0.08 at the 90th percentile, and when estimated from βFS (Ptrend = 7.6 × 10−7): 0.42 ± 0.03 at the 10th, 0.44 ± 0.04 at the 25th, 0.56 ± 0.05 at the 50th, 0.73 ± 0.08 at the 75th, and 0.79 ± 0.11 at the 90th percentile. Consistent with quantile-dependent expressivity, adiponectin’s: (1) heritability was greater in women in accordance with their higher adiponection concentrations; (2) relationships to ADIPOQ polymorphisms were modified by adiposity in accordance with its adiponectin-lowering effect; (3) response to rosiglitazone was predicted by the 45T> G ADIPOQ polymorphism; (4) difference by ADIPOQ haplotypes increased linearly with increasing postprandial adiponectin concentrations.

Conclusion

Adiponectin heritability is quantile dependent, which may explain sex-specific heritability, gene-environment and gene-drug interactions, and postprandial response by haplotypes.
Chemical and Microbiological Assessment of Aadun Produced from Varying Proportions of Maize and Plantain Blends
Authors: Ibitoye F. O. , Elehinafe T. R. , Komolafe O. Y. , Osaloni A. R.
Published: October 2020

In this study, a maize based local snack aadun was formulated from yellow maize flour and ripe plantain blends in a bid to improve its quality. The snacks were subjected to microbial analysis using pour plate method, proximate composition, mineral content and the sensory properties of the snacks were assessed. The results indicated bacterial count ranging from 1.20 to 2.80 x 102 cfu/g. Also, there were no coliforms and enteric bacteria on the aadun samples albeit, there were more bacteria on aadun supplemented with plantain. Two bacteria and three fungi were isolated from the aadun samples, they were Bacillus subtilis, Staphylococcus aureus, Saccharomyces cerevisiae, Aspergillus niger, and Rhizopus stolonifer. The protein and carbohydrate were comparable for the samples while the higher moisture, fiber, ash and carbohydrate were recorded in plantain supplemented aadun with significant increase at a higher content of plantain. Sample C had the highest moisture (6.72%), fiber (7.62%) and ash (2.39%) content in comparison with the other samples whereas, the plain aadun had higher crude fat (32.29%) compared with the aadun containing plantain. The level of calcium and magnesium in the plain and aadun containing plantain were similar without significant differences. However, the level of potassium and phosphorus were significantly higher in aadun supplemented with plantain than in the plain aadun whereas sodium was found to be higher in plain aadun (289.20 mg) than the supplemented samples. There was no significant difference in the appearance and aroma of the plain aadun and plantain supplemented aadun. However, aadun with 50% plantain was ranked as the most preferred samples in terms of taste, texture and overall acceptability with a score of 8.41, 6.31 and 8.33 while the plain aadun had 4.52, 4.22 and 5.79 respectively for these properties. These indicate that aadun may be improved with inclusion of plantainup to 50% proportion.
Natural Antimicrobial Peptides: An Emerging Therapeutic Agent against Pathogens
Authors: Kumar Abhishek , Yadav Shilpi , Sankhwar Ruchi , Gupta Ravi Kr.
Published: October 2020

The rate of discovery of new antibiotic is slower than the emergence of antibiotic-resistant strains in the environment. This global problem is more acute in developing countries. Therefore, it is necessary to develop some alternative approaches to combat infections caused by pathogenic microorganisms and resistant strains. Natural antimicrobial peptides (NAMPs) are potent antimicrobial peptides that are isolated from different sources like plants, animals, humans, bacteria, and fungi. These antimicrobial peptides may have a ribosomal or non-ribosomal origin. Natural antimicrobial peptides have diverse functions in agriculture, pharmaceutical and food industries. NAMPs have been used as food preservatives against food-borne pathogens thereby increasing the shelf-life of food items. NAMPs are useful in the treatment of wounds, ulcers, skin and soft tissue infections caused by microorganisms. Different types of NAMPs are universal in nature and show broad-spectrum antimicrobial activities. NAMPs exhibit great potency against multidrug-resistant bacteria like methicillin-resistant Staphylococcus aureus (MRSA). They have unique characteristics of targeting multiple pathogenic strains and prevent the emergence of natural resistance. In this review article, we systematically discussed different types of natural antimicrobial peptides, their classification, expression, diversity and source. We also explored their mode of action, genetic regulation and application as an alternative therapeutic agent.
Process and mechanism of land acquisition and land tenure security in informal settlements in Nairobi
Authors: Ono Haruka , Kidokoro Tetsuo
Published: October 2020

Urbanization and informal settlements are a prevalent phenomenon in most African regions; they play an important role in the real estate market and the housing supply. This study examines the process and mechanism of land acquisition and land tenure security in informal settlements in Nairobi. We found that pseudo‐customary and pseudo‐formal systems work together in land acquisition and land tenure security. The former system derives from land acquisition and land tenure security under the authority of a traditional chief in rural areas, whereas the latter refers to the modern land registration procedure and urban planning standards. To ensure land acquisition and land tenure security, people use each of these systems and sometimes combine them. Moreover this study demonstrates that these land‐related systems are closely connected to the governance structure and site layout planning.
Suppressing Co‐Crystallization of Halogenated Non‐Fullerene Acceptors for Thermally Stable Ternary Solar Cells
Authors: Hultmark Sandra , Paleti Sri Harish Kumar , Harillo Albert , Marina Sara , Nugroho Ferry Anggoro Ardy , Liu Yanfeng , Ericsson Leif K. E. , Li Ruipeng , Martín Jaime , Bergqvist Jonas , Langhammer Christoph , Zhang Fengling , Yu Liyang , Campoy‐Quiles Mariano , Moons Ellen , Baran Derya , Müller Christian
Published: October 2020

While photovoltaic blends based on non‐fullerene acceptors are touted for their thermal stability, this type of acceptor tends to crystallize, which can result in a gradual decrease in photovoltaic performance and affects the reproducibility of the devices. Two halogenated indacenodithienothiophene‐based acceptors that readily co‐crystallize upon mixing are studied, which indicates that the use of an acceptor mixture alone does not guarantee the formation of a disordered mixture. The addition of the donor polymer to the acceptor mixture readily suppresses the crystallization, which results in a fine‐grained ternary blend with nanometer‐sized domains that do not coarsen due to a high Tg ≈ 200 °C. As a result, annealing at temperatures of up to 170 °C does not markedly affect the photovoltaic performance of ternary devices, in contrast to binary devices that suffer from acceptor crystallization in the active layer. The results indicate that the ternary approach enables the use of high‐temperature processing protocols, which are needed for upscaling and high‐throughput fabrication of organic solar cells. Further, ternary devices display a stable photovoltaic performance at 130 °C for at least 205 h, which indicates that the use of acceptor mixtures allows to fabricate devices with excellent thermal stability.
Holographic Optical Elements for Augmented Reality: Principles, Present Status, and Future Perspectives
Authors: Xiong Jianghao , Yin Kun , Li Kun , Wu Shin-Tson
Published: October 2020

Holographic optical elements (HOEs) exhibit several unique properties in arbitrary wavefront recording and extraction. Versatile recording mechanisms and material availabilities further expand their design flexibilities. Augmented reality (AR) displays are emerging and transforming daily life. Applications of HOEs in AR have harvested numerous fruitful evolutionary and revolutionary progresses. Herein, the basic operation principles of HOEs are elucidated, recent advances in AR systems are reviewed, and their future perspectives are discussed.
Decoupled Electrochemical Water Splitting: From Fundamentals to Applications
Authors: McHugh Patrick J. , Stergiou Athanasios D. , Symes Mark D.
Published: October 2020

Electrolytic water splitting to generate hydrogen and oxygen is one of the most promising ways in which to harness intermittent renewable power sources and store the energy these provide as a clean‐burning and sustainable fuel. In recent years, this has led to an explosion in reports on electrochemical water splitting, most of them focused on improving the efficiency of the electrochemical reactions themselves. However, efficient generation of hydrogen and oxygen is of little use if these products cannot be kept separate and the community is now coming to realize that there are considerable challenges associated with maintaining adequate separation between H2 and O2 during electrolysis driven by intermittent renewable sources. Decoupled electrolysis (whereby oxygen production occurs with reduction of a suitable mediator and hydrogen production is then paired with the reoxidation of this mediator) offers a solution to many of these challenges by allowing O2 and H2 to be produced at different times, at different rates, and even in completely different electrochemical cells. In this review, an overview of recent progress in the field of decoupled electrolysis for water splitting is given and the potential that this approach has for enabling a range of other sustainable chemical processes is explored.
Synthesis and biological evaluations of mono‐ and bis‐ferrocene uracil derivatives
Authors: Djaković Senka , Glavaš‐Obrovac Ljubica , Lapić Jasmina , Maračić Silvija , Kirchofer Juraj , Knežević Marija , Jukić Marijana , Raić‐Malić Silvana
Published: October 2020

Mono‐ (3a–3e and 4a–4e) and bis‐ferrocene (5a–5e and 6a–6e) conjugated 5‐substituted uracil derivatives that are bridged by 1,2,3‐triazole linker were synthesized. The impact of ferrocene unit and spacer between ferrocene and triazole on radical scavenging potency was observed. Bis‐ferrocenyl uracil derivatives exhibited better antiproliferative activities than their mono‐ferrocenyl analogs. Bis‐ferrocenyl methyl‐ (5b) and halogen‐substituted (5e, 6c, and 6d) uracil derivatives showed pronounced and selective cytostatic activities on colon adenocarcinoma (CaCo‐2) and Burkitt lymphoma (Raji) cells, with higher potency and selectivity than the reference drug 5‐fluorouracil. Generation of reactive oxygen species (ROS) in CaCo‐2 and Raji cells when treated with compounds 5b, 5e, and 6d was observed. Bis‐ferrocenyl 5‐chlorouracil 6c induced significant disruption in mitochondrial membrane potential that is accompanied by activation of apoptosis in CaCo‐2, Raji, and acute lymphoblastic leukemia (CCRF‐CEM) cells, while 6d caused mitochondrial dysfunction and apoptosis induction in CaCo‐2 and Raji cells. Potent antiproliferative activity of 6c and 6d could be associated with mitochondrial membrane potential disruption accompanied by apoptosis induction. Our findings highlighted 6c and 6d with potent and selective antiproliferative activity on CaCo‐2, Raji, and CCRF‐CEM cells that may be associated with targeting cancer cell mitochondria, as a molecular target.
Tuning oxygen reduction activity on chromia surface via alloying: a DFT study
Authors: Ng Man‐Fai , Blackwood Daniel John , Jin Hongmei , Tan Teck Leong
Published: October 2020

Economical electro‐catalysts for the oxygen reduction reaction (ORR) are highly desirable for a range of advance energy storage technologies. Chromium compounds have been suggested as one possible source of non‐precious metal based catalysts for oxygen reduction reaction (ORR), especially chromia (Cr2O3) which is the most stable form of Cr oxide at room temperature. Using density functional theory+U calculations, we investigate the 4‐electron ORR on the hydroxylated Cr2O3 surfaces alloyed with 17 different transition metals. On the one hand, we find that the ORR overpotential is lower when the Cr2O3 surface alloyed with elements towards the end of both the first and second rows of transition metals. Among these elements, Cd alloyed Cr2O3 surface is found to promote the ORR the most, but due to its high toxicity and price it loses out to Zn as the recommended alloyant. On the other hand, we find that the ORR overpotential is generally higher and less varied on the Cr2O3 surface alloyed with the early‐to‐mid row transition metal elements (e. g. Zr, Ti). As Cr2O3 is also a major component in the passive film on stainless steels, where a low ORR rate is desirable to reduce the impact of localized corrosion. This implies that alloying with early‐to‐mid row transition elements could be beneficial to stainless steels. The difference in oxygen reduction activity is attributed to the tendency of forming stable ORR intermediates during the oxygen reduction process.
Improved Antiproliferative Activity and Fluorescence of a Dinuclear Gold(I) Bisimidazolylidene Complex via Anthracene‐Modification
Authors: Jakob Christian H. G. , Dominelli Bruno , Schlagintweit Jonas F. , Fischer Pauline J. , Schuderer Franziska , Reich Robert M. , Marques Fernanda , Correia João D. G. , Kühn Fritz E.
Published: October 2020

A straightforward modification route to obtain mono‐ and di‐substituted anthroyl ester bridge functionalized dinuclear Au(I) bis‐N‐heterocyclic carbene complexes is presented. The functionalization can be achieved starting from a hydroxyl‐functionalized ligand precursor followed by transmetallation of the corresponding Ag complex or via esterification of the hydroxyl‐functionalized gold complex. The compounds are characterized by NMR‐spectroscopy, ESI‐MS, elemental analysis and SC‐XRD. The mono‐ester Au complex shows quantum yields around 18%. In contrast, the corresponding syn‐di‐ester Au complex, exhibits significantly lower quantum yields of around 8%. Due to insufficient water solubility of the di‐ester, only the mono‐ester complex has been tested regarding its antiproliferative activity against HeLa‐ (cervix) and MCF‐7‐ (breast) cancer cell lines and a healthy fibroblast cell line (V79). IC50 values of 7.26 μM in the HeLa cell line and 7.92 μM in the MCF‐7 cell line along with selectivity indices of 8.8 (HeLa) and 8.0 (MCF‐7) are obtained. These selectivity indices are significantly higher than those obtained for the reference drugs cisplatin or auranofin.
Using student‐centered approaches to teach the biochemistry of SARS‐CoV‐2
Authors: Zewail‐Foote Maha
Published: October 2020

A biochemistry class was transformed to implement student‐centered, active‐learning pedagogies to help improve competencies associated with the scientific method. In responding to the COVID‐19 pandemic, the course content switched from the biochemistry of nucleic acids to the science of the newly discovered virus, SARS‐CoV‐2. This provided a unique opportunity to model authentic science inquiry through cycles of questioning, investigating, assessing, and critical thinking on a rapidly evolving, interdisciplinary topic. This learning experience helped enhance science literacy, supported self‐directed learning and curiosity, and emphasized the importance of evaluating information sources to recognize misinformation.
Validation of a HPLC method for quantification of midazolam in rat plasma: Application during a Maytenus ilicifolia–drug interaction study
Authors: do Nascimento Sara Batista , de Lima Nascimento Mariana , Duarte‐Almeida Joaquim Maurício , de Oliveira Flávio Martins , do Carmo Vieira Maria , Siqueira João Máximo , de Andrade Frank Pereira , da Costa César Isabela , de Castro Whocely Victor
Published: October 2020

Midazolam (MDZ) is routinely employed as a marker compound of cytochrome P450 3A (CYP3A) activity. Despite the many HPLC–UV methods described to quantify MDZ in plasma, all of them use acetonitrile (ACN) or a mixture of methanol–isopropanol as organic solvent of the mobile phase. Since the ACN shortage in 2008, efforts have been made to replace this solvent during HPLC analysis. A simple, sensitive, accurate and repeatable HPLC–UV method (220 nm) was developed and validated to quantify MDZ in rat plasma using methanol instead. The method was applied during a herb–drug interaction study involving Maytenus ilicifolia, a Brazilian folk medicine used to treat gastric disorders. Plasma samples were alkalinized and MDZ plus alprazolam (internal standard) were extracted with diethyl ether. After solvent removal, the residue was reconstituted with methanol–water (1:1). The analyte was eluted throughout a C18 column using sodium acetate buffer (10 mm, pH 7.4)–methanol (40:60, v/v). The precision at the lower limit of quantification never exceeded 19.40%, and 13.86% at the higher levels of quality control standards, whereas the accuracy ranged from −19.81 to 14.33%. The analytical curve was linear from 50 to 2,000 ng/ml. The activity of the hepatic CYP3A enzymes was not affected by the extract.
Hidden dangers and updated labels on gastric balloons
Authors: Kolli Sindhura , Ofosu Andrew , Gurram Harini , Weissman Simcha , Dang‐Ho Paul Khoi , Mehta Tej I. , Gill Hailie , Gurram Krishna C.
Published: October 2020

In recent years, intragastric balloons (IGBs) have emerged as an efficacious, nonsurgical modality to treat obesity. We present a case in which an IGB caused a gastric ulcer, only unearthed after the novel technique of deflation and early retrieval.
“Ship‐in‐a‐Bottle” Strategy for Immobilization of 9‐Amino(9‐deoxy)epi‐Cinchona Alkaloid into Molecularly Imprinted Solid Acid: Acetal Hydrolysis/Asymmetric Aldol Tandem Reaction
Authors: Wei Shuai , Zhang Jianing , Li Shan , Ma Xuebing
Published: October 2020

Direct immobilization of versatile 9‐amino(9‐deoxy)epi‐cinchona alkaloids without molecule modification to achieve heterogeneous organocatalysis is of interest in the low‐cost production of optically active compounds. In this paper, an exquisite “ship‐in‐a‐bottle” strategy for direct and simple immobilization of 9‐amino‐(9‐deoxy)epi‐quinine (QNNH2) into hollow polystyrene nano‐bowl with imprinted free space around −SO3H was developed via acid‐base reaction and radical polymerization. The heterogeneous organocatalyst with 0.44 mmol g−1 of QNNH2 and 0.48 mmol g−1 of residual −SO3H possessed fast mass transfer due to the characteristic architectural features, such as thin shell thickness, free space around catalytic site, and hollow interior. In heterogeneous acetal hydrolysis/asymmetric aldol tandem reaction, good to excellent catalytic performances (90–95 % yields, anti/syn=88/12–96/4, and 97–99 % ee anti) for acetals bearing electron‐withdrawing substituents (R=o, m, p‐NO2, Cl) were achieved. The “ship‐in‐a‐bottle” QNNH2 displayed good stability and reusability with excellent catalytic performances in the reuses.
Cation‐Specific Electrokinetic Separations Using Prussian Blue Intercalation Reactions
Authors: Thompson Jonathan R. , Davies Collin D. , Clausmeyer Jan , Crooks Richard M.
Published: October 2020

We report a new approach for forming ion depletion zones (IDZs) using intercalation reactions at an electrochemically controlled Prussian blue (PB) film. The experiments described here were performed using a microfluidic device, wherein a charged fluorophore in solution was used as a proxy to monitor IDZ formation. In the presence of K+, intercalation reactions proceed readily to form an IDZ, and thus enrich the fluorophore up to 37‐fold. In the presence of the larger hydrated Li+ or tetrabutylammonium (TBA+) ions, however, ion intercalation proceeded less quickly than with K+. Slower ion intercalation resulted in a weaker IDZ and correspondingly lower enrichment factors of eight‐ and six‐fold, respectively. These results are significant because they show that PB intercalation reactions selectively form an IDZ. Accordingly, we anticipate that these findings will lead to a better understanding and further interesting applications of intercalation materials like PB for efficient and selective enrichment and separations.
Polyterthiophenes Cross‐Linked with Terpyridyl Metal Complexes for Molecular Architecture of Optically and Electrochemically Tunable Materials
Authors: Wagner Michal , Wagner Klaudia , Barnsley Jonathan E. , Veksha Andrei , Wagner Paweł , Gordon Keith C. , Bobacka Johan , Wallace Gordon G. , Ivaska Ari , Officer David L. , Lisak Grzegorz
Published: October 2020

Novel conductive polymer‐based metal complexes were electrochemically synthesized and characterized in relation to (spectro)electrochemical stimuli. Particularly, we focused our attention on terthiophenes functionalized with terpyridine groups, along with Fe2+ cations present during electrochemical synthesis. The resultant electroactive films are coherent, robust, and exhibit mixed absorption profiles upon electrochemical doping, characteristic for both polyterthiophenes and metal‐ligand transitions. At certain oxidation potentials, the formation of radical cation and also dication states were observed. The latter, influence the optical transitions related to metal centers, and can reversibly be everted by switching to lower potentials. Furthermore, the polymer “cross‐linking metal” can be removed from the structure, which we obtained by partial exchange of Fe2+ with Cu2+ and Zn2+ cations. The conducted cation exchange studies however elucidate the complexity and difficulty of such an approach. With future electropolymerization “strategies” we are expecting to extend film stability during application of relatively high potentials, as well as in the interim of cation exchange.
A Novel Cathode Based on Selenium Confined in Biomass Carbon and Graphene Oxide for Potassium‐Selenium Battery
Authors: Cai Ruizheng , Chen Xinxin , Liu Penggao , Chen Tao , Liu Weifang , Fan Xiaowen , Ouyang Baixue , Liu Kaiyu
Published: October 2020

Selenium exhibits smaller volume expansion and much higher electrical conductivity compared with sulfur, which makes it considered as a potential cathode material. In order to improve electrochemical performance of potassium‐selenium (K−Se) batteries, we prepared porous carbon/Se (PC/Se) composite via carbonization, KOH activation and melt diffusion and synthesized a novel porous carbon/Se/graphene oxide (PC/Se/GO) composite with the Se content of ∼40 % via controlling the ionic strength of the solution as cathode material in the work. The combination of porous carbon structure and graphene can effectively relieve the volume expansion of selenium during the charge and discharge process, and provide excellent conductivity. The one‐step conversion without polyselenides between the PC/Se/GO composite and metal potassium further improves the capacity and cycling stability. Therefore, the PC/Se/GO delivers high discharge capacities of 426.3 and 316.8 mAh g−1 in the 2nd and 150th cycles at 0.5 C. This work plays an important reference role for the exploration of advanced potassium‐selenium batteries.
Cobalt‐Free Pr0.5Ba0.4Sr0.1FeO3–δ as a Highly Efficient Cathode for Commercial YSZ‐Supported Solid Oxide Fuel Cell
Authors: Kim Hyunmin , Joo Sangwook , Kwon Ohhun , Choi Sihyuk , Kim Guntae
Published: October 2020

Cobalt‐free perovskite oxides with mixed ionic and electronic conducting (MIEC) properties have been considered as promising alternatives for solid oxide fuel cell (SOFC) cathode material. Among the cobalt‐free perovskite oxides, iron‐based perovskite oxides have received much spotlight as potential candidates for high‐temperature SOFC cathode material attributed to their great catalytic activity for the oxygen reduction reaction (ORR) and excellent cell operation durability. Herein, Sr‐doped Pr0.5Ba0.4Sr0.1FeO3–δ (PBSF) is presented with the aims of enhancing the catalytic activity for ORR while retaining great durability for yttria‐stabilized zirconia (YSZ)‐supported SOFC. The developed PBSF exhibited outstanding cathodic polarization resistance of 0.05 Ω cm2 at 850 °C, which is 3 times lower than the commercial La1–xSrxMnO3–δ. Furthermore, there is no observable degradation for 50 hours. This study presents a great potential to replace the commercial cathodes for YSZ‐supported SOFC.
Concise Total Syntheses of Bioactive Alkaloids Enabled by Development or Application of Cascade Reactions: A Personnel Adventure
Authors: Xie Xingang , She Xuegong
Published: October 2020

Design and development of new tactics and strategies to improve synthetic efficiency is a hot topic and main concern in nowadays’ chemical synthesis of bioactive natural products. Cascade reactions, which construct several bonds in one step via an orchestrated sequence, have been regarded as an important tactic to rapidly increase the molecular complexity, therefor to improve the synthetic efficiency. In this perspective account, we demonstrated and highlighted the significance of cascade reaction developments and applications in concise syntheses of bioactive alkaloids based on our own recent adventure in this research field.

What is the most favorite and original chemistry developed in your research group?

Total synthesis of bioactive natural products is the most favorite chemistry in my research group and development or application of new strategies to improve the synthetic efficiency is the most original chemistry developed in my research group.

How do you get into this specific field? Could you please share some experiences with our readers?

My PhD project was total synthesis of bioactive natural lignans and I devoted myself into synthetic methodology development during my postdoctoral research period. In my opinion, a highly efficient synthetic method will greatly shorten the synthetic route and improve its efficiency for a target‐oriented total synthesis. On the other hand, target‐oriented total synthesis is the best platform to evaluate the practical value of a synthetic method. So I choose total synthesis of natural products and target‐oriented synthetic methodology development as my research fields when I began my independent research.

How do you supervise your students?

When the students start their projects, I discuss the research subjects with them once a month. Every Saturday night we hold a group meeting to learn and discuss the most recent published literatures related to our research. I give more encouragement when the students meet difficulties in their research. Then we try to solve the difficulties together.

What is the most important personality for scientific research?

In my view, diligence and persistence are the most important personalities for scientific research.

What's your hobby? What's your favorite book(s)?

Reading. My favorite book is Sapiens‐a brief history of humankind.

How do you keep balance between research and family?

I usually spend six days (from Monday to Saturday) on research work. On Sunday I will cook some delicious food and enjoy it with my family. My wife understands and supports my work very well. She has done a lot for our family.
Inorganic Semiconductor Quantum Dots as a Saturated Excitation (SAX) Probe for Sub‐Diffraction Imaging
Authors: Kumar Singh Avinash , Burkhow Sadie J. , Wijesooriya Chamari , Boote Brett W. , Petrich Jacob W. , Smith Emily A.
Published: October 2020

The photoluminescence (PL) saturation of CdSe/ZnS core/shell inorganic semiconductor quantum dots (QDs) and its utility as a probe for saturated excitation (SAX) microscopy are reported. Under saturating excitation power densities, the PL signal was demodulated and recorded at harmonics of the fundamental frequency. For commercially available Qdot® 655 ITK™ QDs, the power density required to achieve saturation was dependent upon the local environment of the QDs. For QDs deposited and dried on a glass substrate, the excitation power density required for PL saturation was less than 1 kW/cm2. Compared to this, saturation of PL for QDs dispersed in water required an excitation power density greater than 200 kW/cm2. This observation is manifested as a limitation in the imaging of hydrated samples, as demonstrated for HeLa cells labelled with biotinylated‐phalloidin followed by labelling with streptavidin‐coated QDs. As saturation affects the obtained spatial resolution in several imaging formats, including confocal imaging, the provided data will aid in obtaining the optimal spatial resolution when using QD probes to image biological samples.
Effectiveness of metakaolin and hybrid polymers incorporated mortar for the compressive strength and acid resistance of industrial and wastewater infrastructure
Authors: Idrees Maria , Hussain Arbab Talib , Saeed Farhan , Hussain Tousif
Published: October 2020

Concrete used in sewer pipes and industrial areas is susceptible to acid attacks that can significantly damage wastewater infrastructure. This investigation addresses the effect of using both mineral and polymer admixtures on the flowability, compressive strength, and the resistance against sulfuric acid and hydrochloric acid attacks on the modified mortars. The cement was replaced by 10% and 15% of metakaolin along with 5% of two polymer powders: ethylene‐vinyl‐acetate and polyvinyl‐acetate. Raw kaolin clay was heated at 800°C for 8 hours to produce metakaolin. The pozzolanic activity was determined by both strength‐activity index and X‐ray diffraction method. A total of 180 specimens was cast and tested for compressive strength and acid resistance. The outcomes revealed that the workability, along with compressive strength, was improved significantly up to 24% and 18.43%, respectively. While acid resistance of modified mortar was also enhanced considerably by 59.9% and 24.9% against hydrochloric and sulfuric acids, respectively, proving the combinations to be very effective against acid attacks. The investigation focuses on resolving the major wastewater infrastructure issue besides acid utilizing industry and leads toward sustainability. Much sustainable, durable, and environment‐friendly mortar compositions have been suggested to be used in areas prone to acid attacks.
Performance evaluation of aquaporin forward osmosis membrane using chemical fertilizers as a draw solution
Authors: Mirshekar Leila , Kamarehie Bahram , Jafari Ali , Ghaderpoori Mansour , Karami Mohammad Amin , Sahebi Soleyman
Published: October 2020

The performance of a newly commercialized aquaporin (AQP)‐based biomimetic forward osmosis (FO) membrane was evaluated with several commonly used fertilizers ((CO (NH2)2, KCl, CaCl2, (NH4)2SO4 and (NH4)2HPO4) as a draw solutions (DSs) to verifying the possible implementation of this AQP‐FO membrane in the fertigation industry. Also, DS and feed solution (FS) concentrations were evaluated under FO and pressure retarded osmosis (PRO) operation modes. The results showed that CaCl2 seems to be a more suitable DS in terms of the tradeoff between water flux and salt permeability, compared to the other DSs used in this study. However, KCl gained the highest performance in terms of water flux which was 13.9 and 24.1 Lm−2 h−1 in the FO and PRO mode, respectively. The performance of the AQP membrane in terms of water flux and reverse solute flux can be improved by modifying the structural and the membrane inhibitor layer characteristics for utilizing in commercial scales to compete with other available membranes of the FO process.
A novel application of Mangifera indica L and Eugenia uniflora L extracts as antioxidants to control biodiesel oxidation stability
Authors: Neuana Neuana Fernando , de Sousa Barboza Jayne Carlos , dos Santos Ester P. , da Silva Maria Lucia Caetano P.
Published: October 2020

The present research aims to evaluate the effect on the stability of biodiesel during the storage period at 60°C and at low temperatures of the antioxidants from extracts of mango (biodiesel with extracts of mango), pitanga (biodiesel with extracts of pitanga) added at concentrations of 500, 2000, 4000 and 8000 parts per million to soybean biodiesel. All samples were characterized by the tests of acid value, kinematic viscosity, cloud point, pour point, pour point, cold filter plugging point and Fourier transform infrared (FTIR). Through the FTIR, it was observed that the CH and OH regions showed greater intensity for the non‐additive biodiesel (B100) in relation to the additive Biodiesel, which shows the antioxidant effect of the additives on the oxidative stability of biodiesel. The effect of the extracts on thermo‐oxidative stability follows the sequence: mango leaf extracts > pitanga leaf extracts > B100 after 504 h and at the low temperature the effect of antioxidant following sequence: pitanga extract > mango extract > B100 showing the effect of the antioxidant additives of leaf extracts on the stability of soybean biodiesel at regions of high and low temperatures. The mango and pitanga leaves extracts, are very promising as green antioxidant for biodiesel because it allows the longest storage time without deteriorating.
Evolution and Driving Mechanism of Ecological Security Pattern: A Case Study of Yangtze River Urban Agglomeration
Authors: Huang Qianqian , Peng Benhong , Elahi Ehsan , Wan Anxia
Published: October 2020

Urbanization adversely affects the ecological environment and reduces the quality of life in China. In view of the current situation, this study aims to determine the dynamics of the ecological security pattern of urban agglomerations using the Yangtze River urban agglomeration (YRUA) as a case study. We used the pressure–state–response (PSR) framework to establish an ecological security assessment system, combined with the technique for order of preference by similarity to an ideal solution (TOPSIS) method and gray correlation method, to estimate a comprehensive ecological security index, and we analyzed its evolution trends and driving mechanisms. The results indicated that the distribution of the regional ecological security level had a linked effect and that industrial pollutants posed the greatest threat to ecological security. Moreover, the main factors affecting the YRUA were urbanization, ecopathology, economic development, population pressure, land pressure, and water resource pressure. For the protection of ecological security, it is necessary to establish an ecological security governance mechanism. Moreover, the study stresses changing the traditional sewage discharge model and establishing an ecologically safe market system. Integr Environ Assess Manag 2021;17:573–583. © 2020 SETAC

KEY POINTS

Based on the scale of ecological source, this paper uses the method of combining technique for order of preference by similarity to an ideal solution (TOPSIS) and gray correlation to calculate the ecological security index of an urban agglomeration. Taking Yangtze River Urban Agglomeration as an example, this paper studies the evolution trend of its ecological security, which is of great significance to the study of ecological environment of other urban agglomerations. It is reasonable and general to explore the ecological security situation with the pressure–state–response (PSR) model. The conclusion of this paper is innovative and practical.
Local volumetric mass transfer coefficient estimation for Scenedesmus microalgae culture in a cylindrical airlift photobioreactor
Authors: Ojah Aastha , Sabri Laith S , Aldahhan Muthanna H
Published: October 2020

A plug flow model without axial dispersion was utilized to evaluate the mass transfer coefficient in Scenedesmus microalgae culture grown in a split airlift photobioreactor. The local volumetric mass transfer coefficient and the local interfacial area also were calculated at various gas velocity (1.0, 2.0 and 2.8 cm s–1). In the riser and the downcomer section, the local volumetric mass transfer coefficients were dominated by interfacial area and gas holdup values, and were favored by lower optical densities (ODs) and higher values of superficial gas velocities of microalgae cultures. The OD effects on the liquid side and the local volumetric mass transfer coefficient were analyzed over the growth period divided into three zones: Zone I, for OD ≤0.08; Zone II, OD between 0.08 and 0.19; and Zone III, OD between 0.19 and 0.30. Although the local volumetric mass transfer coefficient was constant axially in the riser, it decreased axially on moving through the downcomer. The estimated local volumetric mass transfer coefficient was found always to be higher than that estimated from the available correlations. © 2020 Society of Chemical Industry (SCI)
Step changes in the intertrial interval in the midsession reversal task: Predicting pigeons' performance with the learning‐to‐time model
Authors: Soares Catarina , Santos Cristina , Machado Armando , Vasconcelos Marco
Published: October 2020

Our goal was to assess the role of timing in pigeons' performance in the midsession reversal task. In discrete‐trial sessions, pigeons learned to discriminate between 2 stimuli, S1 and S2. Choices of S1 were reinforced only in the first half of the session and choices of S2 were reinforced only in the second half. Typically, pigeons choose S2 before the contingency reverses (anticipatory errors) and S1 after (perseverative errors), suggesting that they time the interval from the beginning of the session to the contingency reversal. To test this hypothesis, we exposed pigeons to a midsession reversal task and, depending on the group, either increased or decreased the ITI duration. We then contrasted the pigeons' performance with the predictions of the Learning‐to‐Time (LeT) model: In both conditions, preference was expected to reverse at the same time as in the previous sessions. When the ITI was doubled, pigeons' preference reversal occurred at half the trial number but at the same time as in the previous sessions. When the ITI was halved, pigeons' preference reversal occurred at a later trial but at an earlier time than in the previous sessions. Hence, pigeons' performance was only partially consistent with the predictions of LeT, suggesting that besides timing, other sources of control, such as the outcome of previous trials, seem to influence choice.