bluuebunny/crossref_metadata_2025_split huggingface dataset:
[8+3]‐Cycloaddition of Tropones with Azaoxyallyl Cations
Authors: Roy Tony , Jacob Anu , Bhattacharjee Subrata , Biju Akkattu T. 
Published: September 2019

AbstractAlthough azaoxyallyl cations are widely used as 1,3‐dipoles for various cycloaddition reactions leading to nitrogen‐containing heterocycles, their application in higher‐order cycloaddition reaction remains scarce. Herein, we present the [8+3]‐cycloaddition reaction of tropones with in situ generated azaoxyallyl cations allowing the one‐step construction of cycloheptatriene‐fused 1,4‐oxazinones in moderate to good yields. This base‐promoted new carbon‐oxygen and carbon‐nitrogen bond‐forming reaction takes place under mild conditions in the absence of transition metal catalysts.
De novo phenol bioproduction from glucose using biosensor‐assisted microbial coculture engineering
Authors: Guo Xiaoyun , Li Zhenghong , Wang Xiaonan , Wang Jing , Chala Juan , Lu Yinghua , Zhang Haoran 
Published: September 2019

AbstractMicrobial biosynthesis has been extensively adapted for the production of commodity chemicals using renewable feedstocks. This study integrated metabolite biosensors into rationally designed microbial cocultures to achieve high‐efficiency bioproduction of phenol from simple carbon substrate glucose. Specifically, two sets of E. coli–E. coli cocultures were first constructed for accommodation of two independent phenol biosynthesis pathways via 4‐hydroxybenzoate (4HB) and tyrosine (TYR), respectively. Biosensor‐assisted microbial cell selection mechanisms were subsequently incorporated into the coculture systems to address the insufficient pathway intermediate provision that limited the overall bioproduction. For the 4HB‐ and TYR‐dependent pathways, this approach improved the phenol production by 2.3‐ and 3.9‐fold, respectively, compared to the monoculture controls. Notably, the use of biosensor‐assisted cell selection strategy in monocultures resulted in reduced phenol production, highlighting the advantage of coculture engineering for coupling with biosensing. After stepwise optimization, the phenol bioproduction yield of the engineered coculture's reached 0.057 g/g glucose. Furthermore, the coculture biosynthesis was successfully scaled up at both shake flask and bioreactor levels. Overall, the findings of this study demonstrate the outstanding potential of coupling biosensing and modular coculture engineering for advancing microbial biosynthesis of valuable molecules from renewable carbon substrates.
Effect of Seasonal and Regional Variations on Phenolic Compounds of Deverra scoparia (Flowers/Seeds) Methanolic Extract and the Evaluation of Its in Vitro Antioxidant Activity
Authors: Benarfa Adel , Gourine Nadhir , Mahfoudi Reguia , Harrat Mohamed , Yousfi Mohamed 
Published: September 2019

AbstractThe widespread use of Deverra scoparia Coss. & Durieu in Algerian folk‐medicine as a remedy can be relatively attributed to its total phenolic compounds. The current study aimed to provide a scientific basis for optimal collection and usage of Deverra scoparia Coss. & Durieu plant. Hence, 37 samples were gathered from nine sites in Algeria during two seasons 2016 and 2017, then exposed to a green extraction. Total phenolic (TPC), flavonoid (FC) and condensed tannins (CTC) content were estimated spectrophotometrically. The antioxidant activity was measured using five different methods, DPPH., ABTS.+, FRAP, CUPRAC and Fe2+‐chelating. The results have revealed considerable amounts of TPC varied from 804 to 1544 mg GAE/100 g dry matter, FC started from 187 up to 410 mg QE/100 g dry matter and CTC varied from 111 to 394 mg CE/100 g dry matter. The best IC50 values (μg/mL) of DPPH., ABTS•+, FRAP, CUPRAC and Fe2+‐chelating tests were 56.62, 5.41, 21.26, 52.93 and 78.10, respectively. Moreover, high correlations were found between CTC and most of the antioxidant tests. Hence, CTC are suggested to be the principal group of antioxidant activity in Deverra scoparia Coss. & Durieu extracts.
Precise Cu Localization‐Dependent Catalytic Degradation of Organic Pollutants in Water
Authors: Liu Xiang , Huang Yu , Zhao Peiqing , Meng Xu , Astruc Didier 
Published: September 2019

AbstractTwo different synthetic strategies have been employed, wet‐impregnation vs. pre‐incorporation, to control the localization of Cu from interior to external surface of α‐MnO2 octahedral molecular sieves (OMS‐2). CuOx/OMS‐2 exhibits dispersed granular CuOx (x=1 or 0.5) attached and located at the external surface of OMS‐2, whereas Cu‐OMS‐2 shows Cu location within OMS‐2. These results indicate that the catalyst CuOx/OMS‐2 is significantly more active than Cu‐OMS‐2 and OMS‐2 itself in the degradation of organic pollutants. In addition, the catalyst CuOx/OMS‐2 has been successfully reused 10 times without significant decrease in catalytic activity. This work highlights the role of the catalyst location in molecular sieve on the catalytic efficiency of the metal and rationalizes the catalyst optimization in nanocatalyst engineering.
Enhancing Oxygen Reduction Reaction Catalytic Activity Using a Sub‐Stoichiometric CaTiO3−δ Additive
Authors: Mazzapioda Lucia , Lo Vecchio Carmelo , Paolone Annalisa , Salvatore Aricò Antonino , Baglio Vincenzo , Assunta Navarra Maria 
Published: September 2019

AbstractPlatinum scarcity and its high cost have led to the requirement of alternative materials catalysing the oxygen reduction reaction (ORR), which is the main rate‐determining step occurring in electrochemical devices, including metal‐air batteries and fuel cells. We report a study on a sub‐stoichiometric calcium titanate (CaTiO3−δ, CTO) compound used as promoter for the ORR in order to reduce the Pt loading and improve its electrocatalytic activity. Composite catalysts based on Pt/C with different amounts of CTO were prepared and their activity was investigated by rotating disk electrode (RDE). The obtained results proved a higher catalytic activity for the composite electrode, with respect to pure Pt/C, in terms of electrochemically active surface area, oxygen reduction current density, onset potential and stability.
Direct Recycling of Nd–Fe–B Magnets Based on the Recovery of Nd2Fe14B Grains by Acid‐free Electrochemical Etching
Authors: Xu Xuan , Sturm Saso , Samardzija Zoran , Vidmar Janja , Scancar Janez , Rozman Kristina Zuzek 
Published: September 2019

AbstractRecycling of end‐of‐life Nd–Fe–B magnets is an important strategy for reducing the environmental dangers associated with rare‐earth mining and overcoming the supply risks associated with the rare‐earth elements. In this study, a novel concept for recycling of sintered Nd–Fe–B magnets by directly recovering the matrix Nd2Fe14B grains is presented. The procedure is based on the anodic etching of sintered Nd–Fe–B magnets in a nonaqueous dimethylformamide (DMF)/0.3 mol L−1 FeCl2 bath. Selective recovery of Nd2Fe14B grains was realized within the applied current density <5 mA cm−2 based on the etching priority of phases: metallic Nd > intergranular NdFe4B4 > matrix Nd2Fe14B. The total energy consumption of the proposed recycling route is estimated to be 2.99 kWh kg−1, which is comparable to the state‐of‐the‐art methods. However, the proposed recycling route is currently the only procedure that enables repeated recycling of sintered Nd–Fe–B magnets in a closed‐loop system.
The complex existence of γδ T cells following transplantation: the good, the bad and the simply confusing
Authors: Sullivan Lucy C , Shaw Evangeline M , Stankovic Sanda , Snell Gregory I , Brooks Andrew G , Westall Glen P 
Published: September 2019

AbstractGamma delta (γδ) T cells are a highly heterogeneous population of lymphocytes that exhibit innate and adaptive immune properties. Despite comprising the majority of residing lymphocytes in many organs, the role of γδ T cells in transplantation outcomes is under‐researched. γδ T cells can recognise a diverse array of ligands and exert disparate effector functions. As such, they may potentially contribute to both allograft acceptance and rejection, as well as impacting on infection and post‐transplant malignancy. Here, we review the current literature on the role and function of γδ T cells following solid organ and hematopoietic stem cell transplantation.
Nutrient retention and loss during ecosystem succession: revisiting a classic model
Authors: Lajtha Kate 
Published: September 2019

AbstractIn 1975, Vitousek and Reiners proposed a conceptual model relating the net retention of a limiting nutrient to the net biomass accumulation in terrestrial ecosystems, whereby terrestrial systems should be highly conservative of nutrients during ecosystem succession when plants are actively accumulating biomass, but should be relatively leakier in older stands, when net plant biomass accumulation nears zero. The model was based on measurements in the White Mountains of New Hampshire. However, recent data showing that nitrate output in streams is declining across this region even as forests are aging seem to be inconsistent with this theory. Because the more recent data do not match the predictions of the Vitousek and Reiners model, either new hypotheses, or modifications of the original hypothesis, need to be considered. I suggest that the original model can be amended by accounting for increased woody debris; an accumulation of both above and belowground high C:N coarse woody debris from tree mortality in these regenerating forests can lead to high microbial immobilization of N and can explain the recent patterns of declining stream nitrate. Few studies or models have attempted to calculate the impacts of coarse woody debris (CWD) decomposition products to the retention of C and N in forested ecosystems and their receiving streams, but evidence suggests that CWD can significantly affect stream N exports and should be considered in future models of ecosystem biogeochemical cycles.
Comparison of Nile Red and Cell Size Analysis for High‐Throughput Lipid Estimation Within Oleaginous Yeast
Authors: Hicks Robert H. , Chuck Christopher J. , Scott Roderick J. , Leak David J. , Henk Daniel A. 
Published: September 2019

AbstractWith growing interest in oleaginous yeast as producers of future fuels and bulk chemicals, a robust, high‐throughput method for estimating lipid production is required. Although the lipophilic dye Nile red is frequently used to assay large samples of yeast and microalgae, inconsistent stain permeability between species and strains limits its effectiveness for some microorganisms. In this study, the oleaginous yeast Metschnikowia pulcherrima is used to develop a fluorescence‐free, cell‐size‐based image analysis method for estimating lipid production, which is then compared with an optimized Nile red method across several experimental scenarios. Cell size analysis (CSA) outperforms Nile red in all scenarios, correlating well with lipid extraction data when screening multiple strains, screening a subset of strains grown in different conditions, and tracking the lipid accumulation of a culture over time. Stain permeability is shown to vary significantly among the strains trialled, with lipid droplet size and cell wall thickness having a deleterious effect in the permeability of high‐lipid‐accumulating cells. CSA can also allow culture population dynamics to be monitored, providing key process information of cell size distribution in response to changing media compositions.Practical Applications: Nile red is currently the go‐to method for high‐ throughput lipid screening; however, staining inconsistencies in some organisms caused by varying cell morphology makes it challenging to optimize a robust protocol. Although fluorescence‐free methods exist (Raman spectroscopy, Fourier‐transform infrared spectroscopy, GCMS), the need for extensive sample preparation and specialist equipment restricts their widespread adoption. The CSA method presented here offers an accurate, robust, and cheap alternative for the study of microorganisms where fluorescence‐based avenues are not feasible. Furthermore, the population dynamics collected during CSA can easily be applied to bioreactor style processing, where tracking size distributions can provide real time information of culture status. This additional information is valuable even if fluorescence screening is a possibility.
AC dielectrophoretic deformable particle‐particle interactions and their relative motions
Authors: Zhou Teng , Ji Xiang , Shi Liuyong , Zhang Xianman , Song Yongxin , Joo Sang Woo 
Published: September 2019

AbstractThis paper develops a numerical simulation model to research the deformable particle‐particle interactions caused by dielectrophoresis (DEP) under AC electric fields. The DEP force is calculated by using Maxwell stress tensor method, and the hydrodynamic force is obtained by calculating the hydrodynamic stress tensor. Simulation results show that the DEP interactive motion will facilitate the particles forming particle chains that are parallel to the electric field, and the particles with low shear modulus present a lower x‐component velocity. Also, the electric field intensity and particles radius have some effects on the DEP motions, and for different particles, smaller particles with larger electric field intensity easily reach a larger velocity. The numerical research may provide universal guidance for biological cells manipulation and assembly.
Application of flue‐gas foam in thermal‐chemical flooding for medium‐depth heavy oil reservoirs
Authors: Du Qingjun , Liu Hao , Wu Guanghuan , Hou Jian , Zhou Kang , Liu Yongge 
Published: September 2019

AbstractHeat loss in wellbore during steam injection is considerable due to the deep burial of medium‐depth heavy oil reservoirs, leading to a low steam quality in the bottom of well. As for hot water flooding, the mobility ratio between oil and water is small, which decreases oil recovery. Flue‐gas foam assisted thermal‐chemical flooding is a new method for heavy oil reservoir. Compared to hot water flooding, flue‐gas foam assisted thermal‐chemical flooding can decrease oil viscosity, achieving higher sweep efficiency. However, the combined mechanisms of all the injected components have not been studied systematically. In this work, the role of CO2, viscosity reducer and hot water for oil viscosity reduction and distribution characteristics of residual oil were studied using the numerical simulation methods. Results show that although the percentage of viscosity reduction contribution of viscosity reducer can be as high as 60%, only wider range of this effect can help recover more remaining oil effectively. In the presence of flue‐gas foam, CO2 and viscosity reducer can decrease oil viscosity in the upper and bottom layers of the reservoir, respectively. Two parameters of the area proportion of removed‐oil (ARRO) and the average removed‐oil saturation (SDRO) are defined. It is believed that both ARRO and SDRO are quite small for the hot water flooding, which is assisted by viscosity reducer. The flue‐gas foam can obviously expand the area of removed‐oil, but the average removed‐oil saturation is slightly lower. The combination of flue‐gas foam and viscosity reducer is a promising displacement method.
An online cross‐sectional survey of the health risk behaviours among informal caregivers
Authors: Denham Alexandra M. J. , Wynne Olivia , Baker Amanda L. , Spratt Neil J. , Turner Alyna , Magin Parker , Palazzi Kerrin , Bonevski Billie 
Published: September 2019

AbstractIssue addressedInformal caregivers may experience unique barriers to engaging in healthy lifestyles, consequently increasing their risk of chronic disease. Among a convenience sample of informal caregivers, this study aimed to: (a) assess the self‐reported health risk behaviours of low fruit and vegetable consumption, low physical activity, current smoking and hazardous alcohol consumption; (b) examine the demographic, caree condition and country of residence variables associated with each health risk behaviour; and (c) report the engagement in multiple health risk behaviours.MethodsAn online cross‐sectional survey among caregivers in Australia, Canada, New Zealand, the United Kingdom and the United States was conducted. Self‐reported health risk behaviours were assessed and compared to key Australian healthy living guidelines. Logistic regression modelling identified participant factors associated with each health risk behaviour.ResultsOverall, 384 caregivers were included in the analysis. Hazardous alcohol consumption was the only self‐reported health risk behaviour which was much higher than in the general population (60.0%). Caregiver age (P = .018) and country of residence (P = .015) were associated with hazardous alcohol consumption. A majority of caregivers reported engaging in three health risk behaviours (55.0%).ConclusionsCaregivers are engaging in a range of health risk behaviours; however, rates of hazardous alcohol consumption among the sample were high. Health promotion interventions targeted to address alcohol consumption should consider caregiver age and country of residence.So what?This study highlights the health risk behaviours caregivers engage in across a number of countries, and suggests that caregivers require further support to manage alcohol consumption in particular.
Frontline Science: Antagonism between regular and atypical Cxcr3 receptors regulates macrophage migration during infection and injury in zebrafish
Authors: Sommer Frida , Torraca Vincenzo , Kamel Sarah M. , Lombardi Amber , Meijer Annemarie H. 
Published: September 2019

Abstract
The CXCR3-CXCL11 chemokine-signaling axis plays an essential role in infection and inflammation by orchestrating leukocyte trafficking in human and animal models, including zebrafish. Atypical chemokine receptors (ACKRs) play a fundamental regulatory function in signaling networks by shaping chemokine gradients through their ligand scavenging function, while being unable to signal in the classic G-protein-dependent manner. Two copies of the CXCR3 gene in zebrafish, cxcr3.2 and cxcr3.3, are expressed on macrophages and share a highly conserved ligand-binding site. However, Cxcr3.3 has structural characteristics of ACKRs indicative of a ligand-scavenging role. In contrast, we previously showed that Cxcr3.2 is an active CXCR3 receptor because it is required for macrophage motility and recruitment to sites of mycobacterial infection. In this study, we generated a cxcr3.3 CRISPR-mutant to functionally dissect the antagonistic interplay among the cxcr3 paralogs in the immune response. We observed that cxcr3.3 mutants are more susceptible to mycobacterial infection, whereas cxcr3.2 mutants are more resistant. Furthermore, macrophages in the cxcr3.3 mutant are more motile, show higher activation status, and are recruited more efficiently to sites of infection or injury. Our results suggest that Cxcr3.3 is an ACKR that regulates the activity of Cxcr3.2 by scavenging common ligands and that silencing the scavenging function of Cxcr3.3 results in an exacerbated Cxcr3.2 signaling. In human, splice variants of CXCR3 have antagonistic functions and CXCR3 ligands also interact with ACKRs. Therefore, in zebrafish, an analogous regulatory mechanism appears to have evolved after the cxcr3 gene duplication event, through diversification of conventional and atypical receptor variants.
Stability indicating liquid chromatographic method for simultaneous quantification of betamethasone valerate and tazarotene in in vitro and ex vivo studies of complex nanoformulation
Authors: Rapalli Vamshi Krishna , Singhvi Gautam , Gorantla Srividya , Waghule Tejashree , Dubey Sunil Kumar , Saha Ranendra Narayan , Hasnain Md Saquib , Nayak Amit Kumar 
Published: September 2019

AbstractLow‐potency corticosteroid betamethasone valerate and vitamin‐A tazarotene are used in combination for effective treatment of psoriasis. There is no robust high‐performance liquid chromatography analytical technique available for simultaneous estimation of betamethasone valerate and tazarotene in conventional and nanocarriers based formulations. A simple, accurate, robust isocratic high‐performance liquid chromatography method was developed for simultaneous estimation of betamethasone valerate and tazarotene in topical pharmaceutical formulations. The developed method was validated as per the regulatory guidelines. The validated method was linear over the concentration range of 150–6000 ng/mL (r2 > 0.999) at 239 nm wavelength. Limits of detection and quantification of two analytes were 50 and 150 ng/mL, respectively. The %relative standard deviation for intraday and interday precision was less than 2%. The method was also evaluated in the presence of forced degradation conditions. The developed method was successfully applied for in vitro and ex vivo drug release studies of in‐house designed nanoformulations.
Development of a method to screen and isolate bioactive constituents from Stellera chamaejasme by ultrafiltration and liquid chromatography combined with semi‐preparative high‐performance liquid chromatography and high‐speed counter current chromatography
Authors: Hou Wanchao , Xia Jianli , Liu Chunming , Li Sainan , Wu Tong , Huang Yu 
Published: September 2019

AbstractA simple and efficient method based on ultrafiltration with liquid chromatography and mass spectrometry was used for the rapid screening and identification of ligands in the extracts of Stellera chamaejasme. The bound ligands, i.e. daphnoretin, isopimpinellin, chamaechromone, neochamaejasmin A, and chamaejasmine (purity of 96.8, 90.75, 91.41, 93.98, and 98.91%, respectively), were separated by semi‐preparative high‐performance liquid chromatography combined with high‐speed counter‐current chromatography. To the best of our knowledge, this is the first study to report the detection of potent lipoxidase and lactate dehydrogenase inhibitors in Stellera chamaejasme extracts. The results demonstrate that our method of ultrafiltration with liquid chromatography and mass spectrometry combined with mixed chromatography can be used to screen and confirm the bioactivity of all isolated compounds. This method also eliminates the need for separation of inactive compounds, thereby improving efficiency when studying bioactive substances. For some complex mixtures, neither semi‐preparative high‐performance liquid chromatography nor high‐speed counter‐current chromatography can purify all the target active compounds with high purity in a one‐step separation. The combination of the two methods allow for efficient purification of target bioactive compounds with different polarities and physicochemical properties based on their complementary properties.
Bee honey protects astrocytes against oxidative stress: A preliminary in vitro investigation
Authors: Ali Amira Mohammed , Kunugi Hiroshi 
Published: September 2019

AbstractAimBee honey is widely used as a bioactive food to improve general health and produce therapeutic benefits in various physical disorders. It also improves cognitive and mood‐related behaviors and symptoms in mice and humans. Still, its direct effect on brain cells is unclear. Here, we examined the effect of whole honey on the survival of astrocytes exposed to oxidative stress.MethodsCultured cortical astrocytes were treated with honey (0.1%, 0.3%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 3%, and 5% [v/v]) for 24 hours followed by H2O2 (100 μmol/L) for 3 hours. Cellular viability was assessed with MTT assay.ResultsHoney prevented cellular death in a dose‐dependent manner compared with H2O2‐treated cells. Honey at 1% concentration had the most significant effect (P = .015).ConclusionBee honey exerts a neuroprotective effect through its antioxidant activity.