bluuebunny/crossref_metadata_2025 huggingface dataset:
Vertical stratification of plant-pollinator interactions in a temperate grassland
Authors: Klecka Jan , Hadrava Jiří , Koloušková Pavla
Published: May 2018

Visitation of plants by different pollinators depends on individual plant traits, spatial context, and other factors. A neglected aspect of small-scale variation of plant-pollinator interactions is the role of vertical position of flowers. We conducted a series of experiments to study vertical stratification of plant-pollinator interactions in a dry grassland. We observed flower visitors on cut inflorescences of Centaurea scabiosa and Inula salicina placed at different heights above ground in two types of surrounding vegetation: short and tall. Even at such a small-scale, we detected significant shift in total visitation rate of inflorescences in response to their vertical position. In short vegetation, inflorescences close to the ground were visited more frequently, while in tall vegetation, inflorescences placed higher received more visits. Moreover, we found major differences in the composition of the pollinator community on flowers at different heights. In a second experiment, we measured flower visitation rate in inflorescences of Salvia verticillata of variable height. Total flower visitation rate increased markedly with inflorescence height in this case. Data on seed set of individual plants provide evidence for a corresponding positive pollinator-mediated selection on increased inflorescence height. Overall, our results demonstrate strong vertical stratification of plant-pollinator interactions at the scale of mere decimetres. This may have important ecological as well as evolutionary implications.
Symmetric surface waves along a metamaterial dielectric waveguide and a perfectly conducting cylinder covered by a metamaterial layer
Authors: Shestopalov Y. , Kuzmina E.
Published: May 2018

Existence of symmetric complex waves in a metamaterial dielectric rod and a perfectly conducting cylinder of circular cross section covered by a concentric layer of metamaterial, a metamaterial Goubau line, is proved. Analytical investigation and numerical solution of dispersion equations reveal several important properties of running waves inherent to open metal-metamaterial waveguides which have not been reported for waveguides filled with standard media.
Predicting the potential distributions of the invasive cycad scaleAulacaspis yasumatsui(Hemiptera: Diaspididae) under different climate change scenarios and the implications for management
Authors: Wei Jiufeng , Zhao Qing , Zhao Wanqing , Zhang Hufang
Published: May 2018

Cycads are an ancient group of gymnosperms that are popular as landscaping plants, though nearly all of them are threatened or endangered in the wild. The cycad aulacaspis scale (CAS),Aulacaspis yasumatsuiTakagi (Hemiptera: Diaspididae), has become one of the most serious pests of cycads in recent years; however, the potential distribution range and the management approach for this pest are unclear. A potential risk map of cycad aulacaspis scale was created based on occurrence data under different climatic conditions and topology factors in this study. Furthermore, the future potential distributions of CAS were projected for the periods 2050s and 2070s under three different climate change scenarios (GFDL-CM3, HADGEM2-AO and MIROC5) described in the Special Report on Emissions Scenarios of the IPCC (Intergovernmental Panel on Climate Change). The model suggested high environmental suitability for the continents of Asia and North America, where the species has already been recorded. The potential distribution expansions or reductions were also predicted under different climate change conditions. Temperature of Driest Quarter (Bio9) was the most important factor, explaining 48.1% of the distribution of the species. The results also suggested that highly suitable habitat for CAS would exist in the study area if the mean temperature of 15–20 °C in the driest quarter and a mean temperature of 25–28 °C the wettest quarter. This research provides a theoretical reference framework for developing policy to manage and control this invasive pest.
ESTUDANTES DE PEDAGOGIA DA UNIFESP E DA UFPR: PERFIL SOCIOCULTURAL E FORMAÇÃO PARA A DOCÊNCIA
Authors: Knoblauch Adriane , Penna Marieta Gouvêa de Oliveira , Mondardo Giselly Cristini
Published: May 2018

O trabalho apresenta dados do perfil socioeconômico dos estudantes de Pedagogia da UNIFESP – campus Guarulhos ingressantes em 2011 e dos estudantes de Pedagogia da UFPR ingressantes em 2012, a partir de Banco de Dados gerado pelas duas instituições. Os dados corroboram estudos clássicos da sociologia da educação que apontam correlação entre origem social e escolha por cursos superiores. As análises realizadas evidenciam a relevância de se apontar relações entre o perfil sociocultural de alunos de cursos de formação de professores e disposições vinculadas a esse perfil, importantes para se compreender a relação estabelecida por esses estudantes com o conhecimento em seu percurso universitário, ampliando o debate sobre a formação para a docência.
A CONCEPÇÃO DE LÍNGUA APRESENTADA NOS PARÂMETROS CURRICULARES NACIONAIS PARA O ENSINO DE LÍNGUA ESTRANGEIRA NO ENSINO FUNDAMENTAL
Authors: Padilha Emanuele Coimbra
Published: May 2018

Este artigo objetiva identificar a concepção de língua apresentada pelos Parâmetros Curriculares Nacionais (PCNs) de Língua Estrangeira (LE) para o ensino fundamental. O referencial teórico apresenta considerações sobre concepções de língua, um panorama histórico de acontecimentos que marcaram o ensino de línguas estrangeiras no Brasil, desde o surgimento das primeiras escolas, até os PCNs, em 1998. Em seguida, descrevemos os PCNs e discutimos a concepção de língua apresentada por ele. Para finalizar, tecemos as considerações finais. A metodologia utilizada para a identificação da concepção foi a interpretativa com base nos aportes teóricos de Koch (2006) e Travaglia (2009).  Os resultados demonstram que a concepção que permeia o documento é a de que a linguagem é o lugar da interação humana. Por meio dela, ideias, pensamentos e intenções são expressos e os indivíduos estabelecem relações com outras pessoas.
UMA REVISÃO BIBLIOGRÁFICA DA RELAÇÃO ENTRE PROFESSOR E ALUNO NO ENSINO SUPERIOR SOB A ÓTICA DA AFETIVIDADE
Authors: De Magalhães Porto Cristiane , Maurício Fonseca Santos Fábio
Published: May 2018

Este artigo teve como principal objetivo identificar a maneira de se integrar o relacionamento afetivo entre professor e aluno dentro das Instituições de Ensino Superior. Para atingir essas finalidades, a metodologia aplicada na realização deste estudo foi da pesquisa de cunho exploratória, adotando-se a pesquisa bibliográfica como procedimento técnico de coleta de dados. O estudo fundamenta-se, nomeadamente, nas ideias de pensadores como Vygotsky (2003), Piaget (1997) e Wallon (2008), que defendem a afetividade como um conceito-chave na constituição do sujeito e na construção do conhecimento. Os resultados obtidos apontam que na formação docente deve ser considerada a dimensão afetiva, a qual não pode ser tratada de forma separada da inteligência.Palavras-chave: Afetividade. Conhecimento. Ensino Superior.
Matrine suppresses KRAS‐driven pancreatic cancer growth by inhibiting autophagy‐mediated energy metabolism
Authors: Cho Young‐ra , Lee Ji Hyeon , Kim Ji Hye , Lee So‐Yeon , Yoo Suna , Jung Min‐kyo , Kim Su Jung , Yoo Hyun Ju , Pack Chang‐Gi , Rho Jin Kyung , Son Jaekyoung
Published: May 2018

Matrine is a natural compound extracted from the herb Sophora flavescens Ait which is widely used in traditional Chinese medicine for treating various diseases. Recently, matrine was reported to have antitumor effects against a variety of cancers without any obvious side effects; however, the molecular mechanisms of its antiproliferative effects on cancer are unclear. Here, we report that matrine inhibits autophagy‐mediated energy metabolism, which is necessary for pancreatic cancer growth. We found that matrine significantly reduces pancreatic cancer growth in vitro and in vivo by insufficiently maintaining mitochondrial metabolic function and energy level. We also found that either pyruvate or α‐ketoglutarate supplementation markedly rescues pancreatic cancer cell growth following matrine treatment. Inhibition of mitochondrial energy production results from matrine‐mediated autophagy inhibition by impairing the function of lysosomal protease. Matrine‐mediated autophagy inhibition requires stat3 downregulation. Furthermore, we found that the antitumor effect of matrine on pancreatic cancer growth depends on the mutation of the KRAS oncogene. Together, our data suggest that matrine can suppress the growth of KRAS‐mutant pancreatic cancer by inhibiting autophagy‐mediated energy metabolism.
Degradation of histone deacetylase 4 via the TLR4/JAK/STAT1 signaling pathway promotes the acetylation of high mobility group box 1 (HMGB1) in lipopolysaccharide‐activated macrophages
Authors: Park Eun J. , Kim Young M. , Kim Hye J. , Chang Ki C.
Published: May 2018

High mobility group box 1 (HMGB1) has been proposed as crucial in the pathogenesis of many diseases including sepsis. Acetylation of HMGB1 prevents its entry into the nucleus and leads to its secretion from the cell where it can trigger inflammation. We hypothesized that histone deacetylase 4 (HDAC4) controls the acetylation of HMGB1 in lipopolysaccharide (LPS)‐stimulated RAW264.7 cells via the janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway. The results showed that LPS treatment promoted the degradation of HDAC4 in a proteasome‐dependent manner, which led to HMGB1 acetylation. In LPS‐activated RAW264.7 cells, treatment with TAK‐242 (a toll like receptor 4 inhibitor) and pyridone 6 (a JAK inhibitor) significantly inhibited HDAC4 degradation and acetylation of HMGB1, and thus prevented secretion of HMGB1. Decreased phosphorylation of STAT1 was also observed. Interestingly, HDAC4 overexpression significantly prevented the acetylation and secretion of HMGB1 in both RAW264.7 cells and isolated murine peritoneal macrophages. We conclude that HDAC4 might be a useful target for the treatment of sepsis.
Relationship Between Self‐Reported Restless Sleep and Objectively Measured Physical Activity in Adults With Knee Osteoarthritis
Authors: Gilbert Abigail L. , Lee Jungwha , Song Jing , Semanik Pamela A. , Ehrlich‐Jones Linda S. , Kwoh C. Kent , Dunlop Dorothy D. , Chang Rowland W.
Published: May 2018

Objective

Despite the numerous health benefits of physical activity, inactivity is endemic among adults with knee osteoarthritis (OA). Because sleep quality may be a target in order to improve physical activity behavior, we investigated the cross‐sectional relationship between restless sleep and physical activity in participants with or at risk for knee OA.

Methods

We analyzed accelerometer‐measured physical activity and clinical data of participants included in the Osteoarthritis Initiative (OAI). We used multiple regression analysis to evaluate physical activity for participants, who were grouped by the reported frequency of restless sleep, and adjusted for demographic and medical confounders.

Results

Of the 1,892 OAI participants for whom complete data were available, 300 participants (16%) reported restless sleep ≥3 days in the past week. Participants who reported restless sleep for much of the time (3–4 days/week) and most of the time (5–7 days/week) had 11.9% and 23.7% less weekly minutes of moderately vigorous activity, respectively, compared to participants who reported rarely restless sleep (<1 day/week) (P for trend 0.021). These differences persisted after accounting for age, sex, race, body mass index, medical comorbidity, and knee OA severity and pain (P for trend 0.023). Differences related to restless sleep were largely attenuated by the presence of high depressive symptoms and low energy levels.

Conclusion

Poor sleep quality is associated with less physical activity in persons with or at risk for knee OA. Future studies are needed to determine the mechanisms of how poor sleep and physical activity are related, how energy and depression mediate these relationships, and whether interventions that improve sleep quality might result in increased physical activity.
Preparation of Highly Stable Black Phosphorus by Gold Decoration for High‐Performance Thermoelectric Generators
Authors: An Cheng Jin , Kang Young Hun , Lee Changjin , Cho Song Yun
Published: May 2018

For thermoelectric (TE) applications, the surface of exfoliated black phosphorus (BP) can be successfully functionalized with Au nanoparticles (NPs), leading to significantly enhanced TE performance for a controlled Au NP content. A facile and selective decoration of metal species on the defect sites of BP is achieved by the spontaneous formation of Au NPs on the surface of BP through a redox reaction of Au precursors. Such a heterostructure provided by the Au decoration of BP enhances electrical conductivity (from 0.001 to 63.3 S cm−1) through tuning of the charge carrier concentration and retains the initial Seebeck coefficient of BP. Consequently, the TE power factor of the Au‐decorated BP increases significantly to 68.5 µV m−1 K−2, which is 2740 times that of the pristine BP. More significantly, in contrast to the severe degradation of the pristine BP in the air, surface‐functionalized BP exhibits excellent stability upon exposure to air for a long period, which is beneficial for practical TE applications. Given these interesting and unique properties of Au‐decorated BP, a vertical TE generator with a high power output of 79.3 nW (ΔT = 2 °C) is prepared by using the Au‐decorated BP as a p‐type TE material.
Trace Analysis and Reaction Monitoring by Nanophotonic Ionization Mass Spectrometry from Elevated Bowtie and Silicon Nanopost Arrays
Authors: Stopka Sylwia A. , Holmes Xavier A. , Korte Andrew R. , Compton Laine R. , Retterer Scott T. , Vertes Akos
Published: May 2018

Silicon nanopost arrays (NAPA) are used in trace analysis by mass spectrometry (MS) because they enable highly efficient ion production from small molecules and thin tissue sections by UV laser desorption ionization (LDI). Such nanophotonic ionization of adsorbates relies on localized interactions between a nanostructured substrate and laser radiation. In LDI from NAPA, only the component of the oscillating electric field vector that is parallel with the posts couples the laser energy into the nanostructure. Enhancements in control over adsorbate ionization and fragmentation are expected if the surface‐parallel component can also interact with the nanostructure. Here, an alternative nanophotonic ionization platform is introduced for LDI‐MS, the elevated bowtie (EBT) array by adding triangular chromium features on top of silicon post pairs to form bowties. Compared to NAPA, the threshold fluence for ionization from EBT is lower, and at low laser fluences the ionization efficiency is increased by a factor of ≈17. The EBT platform with optimized apex angle exhibits a higher survival yield for molecular ions produced from biomolecules and xenobiotics and allows more control over fragmentation by adjusting the fluence. These unique nanophotonic ionization attributes are utilized for trace analysis and reaction monitoring in complex biological samples.
Smart Anisotropic Wetting Surfaces with Reversed pH‐Responsive Wetting Directions
Authors: Ge Peng , Zhang Jianglei , Liu Yongshun , Wang Shuli , Liu Wendong , Yu Nianzuo , Wu Yuxin , Zhang Junhu , Yang Bai
Published: May 2018

Smart pH‐responsive surfaces that could autonomously induce unidirectional wetting of acid and base with reversed directions are fabricated. The smart surfaces, consisting of chemistry‐asymmetric “Janus” silicon cylinder arrays (Si‐CAs), are prepared by precise modification of functional groups on each cylinder unit. Herein, amino and carboxyl groups are chosen as typical pH‐responsive groups, owing to their protonation/deprotonation effect in response to pH of the contacted aqueous solution. One side of the Si‐CAs is modified by poly(2‐(dimethylamino)ethyl methacrylate), while the other side is modified by mixed self‐assembled monolayers of 1‐dodecanethiol and 11‐mercaptoundecanoic acid. On such surfaces, it is observed that acid and base wet in a unidirectional manner toward corresponding directions that are modified by amino or carboxyl groups, which is caused by asynchronous change of wetting property on two sides of the asymmetric structures. The as‐prepared Janus surfaces could regulate the wetting behavior of acid and base and could direct unidirectional wetting of water with reversed directions when the surfaces are treated by strong acid or base. Due to the excellent response capability, the smart surfaces are potential candidates to be applied in sensors, microfluidics, oil/water separation, and smart interfacial design.
Reversible Sodium and Lithium Insertion in Iron Fluoride Perovskites
Authors: Martin Andréa , Doublet Marie‐Liesse , Kemnitz Erhard , Pinna Nicola
Published: May 2018

Li‐ion batteries are omnipresent in consumer electronics and are seen as the most promising technology for electric vehicles. Na‐ion batteries have emerged as viable and cheaper alternatives for stationary applications where Li‐ion batteries are too expensive. However, the larger size of sodium ion compared to lithium makes traditional positive materials for Li‐ion batteries not always suitable for the reversible insertion of sodium ions. Herein, a microwave‐assisted solution synthesis of NaFeF3 perovskite nanoparticles from presynthesized rutile FeF2 colloidal particles, sodium ethoxide, and ammonium fluoride is presented. This NaFeF3 material shows a reversible electrochemical activity of 1Na or 1Li per iron with low polarization and excellent capacity retention after 100 cycles. The unexpected reversible insertion of both sodium and lithium ions, herein studied through ex situ and operando X‐ray diffraction measurements, is attributed to a kinetic stabilization of corner‐shared cubic AxFeF3 (A = Li, Na) frameworks along the cycles involving low volume change without high thermodynamic cost as supported by a polymorphism theoretical analysis.
Ruthenium‐Catalyzed Site‐selective Enone Carbonyl Directed ortho‐C−H Activation of Aromatics and Heteroaromatics with Alkenes
Authors: Bakthadoss Manickam , Kumar Polu Vijay
Published: May 2018

An efficient and versatile protocol for enone carbonyl directed ortho C−H activation of aromatics and heteroaromatics with alkenes for the construction of functionalized ortho‐olefinated chalcone derivatives in excellent yields in a regio‐ and stereoselective fashion has been developed for the first time. This general protocol involves chelation assisted oxidative coupling in the presence of ruthenium catalyst through C−H bond activation. This protocol has been further emphasized by the exhibition of functional group tolerance.

magnified image
Genome skimming provides new insight into the relationships in Ludwigia section Macrocarpon, a polyploid complex
Authors: Liu Shih‐Hui , Edwards Christine E. , Hoch Peter C. , Raven Peter H. , Barber Janet C.
Published: May 2018

Premise of the Study

Interpreting relationships within groups containing polyploids, which are frequent in angiosperms, can be greatly assisted by genomic techniques. In this study, we used a genome‐skimming approach to investigate the evolutionary relationships and origins of polyploids in the monophyletic group, Ludwigia section Macrocarpon (Onagraceae), which includes diploid, tetraploid, and hexaploid taxa.

Methods

We sampled all known taxa and ploidy levels in the section and conducted shotgun sequencing. We assembled plastomes, mitochondrial sequences, and completed nuclear ribosomal regions, reconstructed phylogenies, and conducted comparative genomic analyses for plastomes to gain insights into the relationships among studied taxa.

Key Results

Within the section, results showed that the South American diploid taxa L. bonariensis and L. lagunae were closely related. We reported the first chromosome count (2n = 4× = 32) for L. neograndiflora, which is closely related to the two South American diploid taxa, although its exact origin remains unclear. The samples of the widespread, polyploid taxon L. octovalvis do not form a monophyletic group. Both tetraploid and hexaploid L. octovalvis lineages have originated more than once. At least one tetraploid in the L. octovalvis lineage may have been involved in the origins of hexaploids. One or more extinct/unsampled intermediate tetraploids in the L. octovalvis lineages had also likely been involved in the origins of hexaploids.

Conclusions

Genome skimming provided important insights into the complex evolutionary relationships within sect. Macrocarpon, but additional sampling and data from single‐copy nuclear regions are necessary to further elucidate the origins of the polyploids in this section.
Genotype–phenotype correlation of hereditary erythrocytosis mutations, a single center experience
Authors: Oliveira Jennifer L. , Coon Lea M. , Frederick Lori A. , Hein Molly , Swanson Kenneth C. , Savedra Michelle E. , Porter Tavanna R. , Patnaik Mrinal M. , Tefferi Ayalew , Pardanani Animesh , Grebe Stefan K. , Viswanatha David S. , Hoyer James D.
Published: May 2018

Hereditary erythrocytosis is associated with high oxygen affinity hemoglobin variants (HOAs), 2,3‐bisphosphoglycerate deficiency and abnormalities in EPOR and the oxygen‐sensing pathway proteins PHD, HIF2α, and VHL. Our laboratory has 40 years of experience with hemoglobin disorder testing and we have characterized HOAs using varied protein and molecular techniques including functional assessment by p50 analysis. In addition, we have more recently commenced adding the assessment of clinically relevant regions of the VHL, BPGM, EPOR, EGLN1 (PHD2), and EPAS1 (HIF2A) genes in a more comprehensive hereditary erythrocytosis panel of tests. Review of our experience confirms a wide spectrum of alterations associated with erythrocytosis which we have correlated with phenotypic and clinical features. Through generic hemoglobinopathy testing, we have identified 762 patients with 81 distinct HOA Hb variants (61 β, 20 α), including 12 that were first identified by our laboratory. Of the 1192 cases received for an evaluation specific for hereditary erythrocytosis, approximately 12% had reportable alterations: 85 pathogenic/likely pathogenic mutations and 58 variants of unknown significance. Many have not been previously reported. Correlation with clinical and phenotypic data supports an algorithmic approach to guide economical evaluation; although, testing is expanded if the suspected causes are negative or of uncertain significance. Clinical features are similar and range from asymptomatic to recurrent headaches, fatigue, restless legs, chest pain, exertional dyspnea and thrombotic episodes. Many patients were chronically phlebotomized with reported relief of symptoms.
Chemo‐enzymatic Total Synthesis of Oxosorbicillinol, Sorrentanone, Rezishanones B and C, Sorbicatechol A, Bisvertinolone, and (+)‐Epoxysorbicillinol
Authors: Sib Anna , Gulder Tobias A. M.
Published: May 2018

The sorbicillinoids are a large family of fungal natural products, many of which possess highly challenging molecular architectures. Depending on their individual structures they exhibit strong biological activities ranging from radical scavenging and anti‐infective properties to cytotoxicity. Despite the resulting strong biomedical potential of these natural products and the interest of synthetic chemists owing to their fascinating structures, many sorbicillinoids are currently not synthetically accessible, thus hampering in‐depth biological characterization and structural diversification. By using recombinant oxidoreductase SorbC and readily accessible sorbicillin‐type synthetic precursors, we have developed enantioselective, one‐pot chemo‐enzymatic routes to a broad range of sorbicillinoids, thereby establishing total syntheses of oxosorbicillinol, sorrentanone, rezishanones B and C, sorbicatechol A, bisvertinolone, and (+)‐epoxysorbicillinol.
Metal complexes of novel Schiff base derived from the condensation of 2‐quinoline carboxaldehyde and ambroxol drug with some transition metal ions
Authors: Mahmoud Walaa H. , Mohamed Gehad G. , Elsawy Hoda A. , Radwan Mostafa A.
Published: May 2018

A new Schiff base was prepared as the condensation product of the reaction of 2‐quinoline carboxaldehyde and ambroxol drug. The Schiff base ligand thus obtained (HL; trans‐4‐[(2‐(2‐quinolinoimino)‐3,5‐dibromobenzyl)amino]cyclohexanol) was further employed as a tridentate ligand for the synthesis of new complexes through reaction with Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) metal ions. The synthesized HL and its metal complexes were characterized using various physicochemical techniques including elemental analysis, Fourier transform infrared and UV–visible spectroscopies, conductimetric and magnetic susceptibility measurements, mass spectrometry and thermal analyses. 1H NMR data indicated that complex formation was through the amino group rather than the aliphatic hydroxyl group. Thermal analysis gave an idea about the decomposition pattern of HL and its complexes. Also, it revealed the number of water molecules in the inner and outer spheres of the complexes. An octahedral geometry for all the complexes has been suggested. HL and its complexes were screened for their antimicrobial activity against various species of bacteria and fungi using the disc diffusion method. The Cr(III) complex had the highest antimicrobial activity.
Pt(II) complexes immobilized on polymer‐modified magnetic carbon nanotubes as a new platinum drug delivery system
Authors: Tabatabaei Rezaei Seyed Jamal , Hesami Ali , Khorramabadi Hossein , Amani Vahid , Malekzadeh Asemeh Mashhadi , Ramazani Ali , Niknejad Hassan
Published: May 2018

We combine nanotechnology and chemical synthesis to create a novel multifunctional platinum drug delivery vehicle based on magnetic carbon nanotubes (multiwall carbon nanotubes/Fe3O4@poly(citric acid)/cis‐[(Pt(1,7‐phenanthroline)(DMSO)Cl2)]‐b‐poly(ethylene glycol) (MCNTs/FO@PC/Pt(II)‐b‐PEG)) for targeted cancer therapy. MCNTs/FO@PC/Pt(II)‐b‐PEG was conveniently prepared by conjugating cis‐[Pt(1,7‐phenanthroline)(DMSO)Cl2] complex to MCNTs/FO@PC‐b‐PEG via strong hydrogen‐bonding interactions. In comparison with free cisplatin and Pt(II) complex, MCNTs/FO@PC/Pt(II)‐b‐PEG shows higher solubility in aqueous solution and higher cytotoxicity towards human cervical cancer HeLa cells and human breast cancer MDA‐MB‐231 cells. In vitro release experiments revealed that the platinum drug‐loaded delivery system is relatively stable under physiological conditions (pH = 7.4 and 37 °C) but susceptible to acidic environments (pH = 5.6 and 37 °C) which would trigger the release of loaded drugs. Fluorescence microscopy studies revealed that this magnetic nanohybrid system possesses marked cell‐specific targeting in vitro in the presence of an external magnetic field. The results indicated that the prepared superparamagnetic MCNTs/FO@PC/Pt(II)‐b‐PEG nanohybrid system is a promising candidate for inhibiting the proliferation of cancer cells.
Hyperpolarized NMR Spectroscopy: d‐DNP, PHIP, and SABRE Techniques
Authors: Kovtunov Kirill V. , Pokochueva Ekaterina V. , Salnikov Oleg G. , Cousin Samuel F. , Kurzbach Dennis , Vuichoud Basile , Jannin Sami , Chekmenev Eduard Y. , Goodson Boyd M. , Barskiy Danila A. , Koptyug Igor V.
Published: May 2018

The intensity of NMR signals can be enhanced by several orders of magnitude by using various techniques for the hyperpolarization of different molecules. Such approaches can overcome the main sensitivity challenges facing modern NMR/magnetic resonance imaging (MRI) techniques, whilst hyperpolarized fluids can also be used in a variety of applications in material science and biomedicine. This Focus Review considers the fundamentals of the preparation of hyperpolarized liquids and gases by using dissolution dynamic nuclear polarization (d‐DNP) and parahydrogen‐based techniques, such as signal amplification by reversible exchange (SABRE) and parahydrogen‐induced polarization (PHIP), in both heterogeneous and homogeneous processes. The various new aspects in the formation and utilization of hyperpolarized fluids, along with the possibility of observing NMR signal enhancement, are described.
Information‐theoretic multistage sampling framework for medical audits
Authors: Musal Muzaffer , Ekin Tahir
Published: May 2018

The sampling resource allocation decisions for medical audits of outpatient procedures are crucial and challenging because of the large payment amounts and heterogeneity of the claims. A number of frameworks are utilized to help auditors address the trade‐offs between efficiency and cost while having valid overpayment amount estimates. As a potential improvement, this paper presents a novel information‐theoretic multistage sampling framework. In particular, we propose an iterative stratified sampling method that uses Lindley's entropy measure to evaluate the expected amount of information. We use US Medicare Part B claims outpatient payment data and investigate the versatility of the framework for different overpayment scenarios and resource allocation designs. The proposed method results in reasonable coverage and lower estimation errors for the proportion of overpaid claims and overpayment recovery amounts. Our sampling method is shown to outperform the current stratification method of practice, ie, Neyman allocation, for many scenarios. The framework also can be used to make probability statements on variables of interest, such as the number of overpaid claims.
Copper nanoclusters as fluorescence‐quenching probes for the quantitative analysis of total iodine
Authors: Cao Xueling , Li Xin , Liu Faxian , Luo Yanan , Yu Liying
Published: May 2018

Tannic acid‐coated copper nanoclusters (CuNCs@TA) were synthesized and used quantitatively to analyze iodine in kelp. Compared with other methods for iodine detection, the proposed method showed excellent performance. The iodine‐induced linear decrease in the fluorescence intensity of CuNCs@TA allowed the quantitative detection of iodine in the range 20–100 μM, and the limit of detection for iodine was 18 nM. The probe can be used for the determination of iodine in real samples with reliable and accurate results. Modified Stern–Volmer equation and thermodynamic calculation studies were used to discuss the quenching mechanism.
Selective Inhibitory Effect of Osthenol on Human Cytochrome 2C8
Authors: Cho Pil Joung , Nam WoongShik , Lee Doohyun , Lee Taeho , Lee Sangkyu
Published: May 2018

Osthenol is a furanocoumarin with anti‐tumor, anti‐inflammatory, and anti‐viral activity. It is present in various citrus juices and fruits; however, its inhibitory effects on cytochrome P450 (CYP) enzyme activity, in the context of herb–drug interaction (HDI) prediction, have not been previously studied. In this study, osthenol was chemically synthesized in order to identify potential HDIs. Its inhibitory effect on eight CYP isoforms and the underlying mechanism of inhibition were investigated by using cocktail assays and liquid chromatography‐tandem mass spectrometry in pooled human liver microsomes. The inhibitory effect of osthenol on CYP2C8‐catalyzed paclitaxel hydroxylation was selective and dose‐dependent, but not time‐dependent. The IC50 value was 2.8 μM. Additionally, osthenol displayed mixed mode inhibition with a relatively low Ki value of 0.96 μM, which is indicative of the potential for HDIs with co‐administered CYP2C8 substrates. To the best of our knowledge, this is the first report of selective inhibition of CYP2C8 by osthenol.
Proline Fingerprint in Intrinsically Disordered Proteins
Authors: Murrali Maria Grazia , Piai Alessandro , Bermel Wolfgang , Felli Isabella C. , Pierattelli Roberta
Published: May 2018

NMR spectroscopy is one of the main techniques used for high‐resolution studies of intrinsically disordered proteins (IDPs), permitting mapping of the structural and dynamic features of all the amino acids constituting the polypeptide at atomic resolution. Only proline residues are less straightforward to characterize because they lack any amide proton, thus rendering them not directly visible in the commonly used 2D 1H,15N correlation experiments. However, proline residues are highly abundant in IDPs and can mediate important functions. In this work we present an easy and effective way to obtain fingerprints of proline residues in IDPs at high resolution.
Protein Regulation by Intrinsically Disordered Regions: A Role for Subdomains in the IDR of the HIV‐1 Rev Protein
Authors: Faust Ofrah , Grunhaus Dana , Shimshon Odelia , Yavin Eylon , Friedler Assaf
Published: May 2018

Intrinsically disordered regions (IDRs) in proteins are highly abundant, but they are still commonly viewed as long stretches of polar, solvent‐accessible residues. Here we show that the disordered C‐terminal domain (CTD) of HIV‐1 Rev has two subregions that carry out two distinct complementary roles of regulating protein oligomerization and contributing to stability. We propose that this takes place through a delicate balance between charged and hydrophobic residues within the IDR. This means that mutations in this region, as well as the known mutations in the structured region of the protein, can affect protein function. We suggest that IDRs in proteins should be divided into subdomains similarly to structured regions, rather than being viewed as long flexible stretches.
Analysis of CO2 Emission and Economic Feasibility for a Heat‐Integrated Air Separation System
Authors: Cong Lin , Chang Liang , Liu Xinggao , Deng Xiaogang , Chen Honglong
Published: May 2018

Cryogenic air separation is a high‐energy consumption process and contributes significantly to greenhouse gas emissions. Reduction potentials of the CO2 emissions for both the full‐tower heat‐integrated air separation columns (F‐HIASC) and the top‐tower heat‐integrated air separation columns (T‐HIASC) are investigated. The optimization models of the minimum CO2 emissions are further proposed. The unit CO2 emissions of F‐HIASC and T‐HIASC can be decreased significantly compared to the conventional air separation columns (CASC). Furthermore, the capital cost and total annual cost are analyzed so as to evaluate properly the economic feasibility of HIASC. The results demonstrate that the total annual costs of F‐HIASC and T‐HIASC are much lower than that of CASC.
Enhanced SO2 Capture Performance of MnO2 by Doping with Alkali Metal Ions for Diesel Emission Control
Authors: Liu Xuecheng , Chen Lintao , Qi Gaoxiang
Published: May 2018

Growing concern about sulfur dioxide (SO2) emission from diesel exhaust causing a serious threat to the environment and human health necessitated enhanced desulfurization materials for dry desulfurization filters. MnO2 was modified with various alkali metal ions by impregnation to strengthen its SO2 capture capacity. The prepared materials were characterized by various technologies. Their SO2 capture capacities were measured by thermogravimetry, and the sulfate reaction mechanism was also evaluated. The results confirm that the SO2 capture performance of MnO2 could be significantly enhanced by doping with alkali metals. The prepared Li‐doped MnO2 has good SO2 trap capacity with improved absorbance being 64 % higher than that of MnO2. The grain model can be applied to explain the sulfate reaction mechanism between Li‐doped MnO2 and SO2. The activation energy was calculated by the grain model equations.
Mechanistic Insights into Selective Oxidation of Polyaromatic Compounds using RICO Chemistry
Authors: Nowicka Ewa , Hickey Niamh W. , Sankar Meenakshisundaram , Jenkins Robert L. , Knight David W. , Willock David J. , Hutchings Graham J. , Francisco Manuel , Taylor Stuart H.
Published: May 2018

Ruthenium‐ion‐catalyzed oxidation (RICO) of polyaromatic hydrocarbons (PAHs) has been studied in detail using experimental and computational approaches to explore the reaction mechanism. DFT calculations show that regioselectivity in these reactions can be understood in terms of the preservation of aromaticity in the initial formation of a [3+2] metallocycle intermediate at the most‐isolated double bond. We identify two competing pathways: C−C bond cleavage leading to a dialdehyde and C‐H activation followed by H migration to the RuOx complex to give diketones. Experimentally, the oxidation of pyrene and phenanthrene has been carried out in monophasic and biphasic solvent systems. Our results show that diketones are the major product for both phenanthrene and pyrene substrates. These diketone products are shown to be stable under our reaction conditions so that higher oxidation products (acids and their derivatives) are assigned to the competing pathway through the dialdehyde. Experiments using 18O‐labelled water do show incorporation of oxygen from the solvents into products, but this may take place during the formation of the reactive RuO4 species rather than directly during PAH oxidation. When the oxidation of pyrene is carried out using D2O, a kinetic isotope effect (KIE) is observed implying that water is involved in the rate‐determining step leading to the diketone products.
Polymorphism, Weak Interactions and Phase Transitions in Chalcogen–Phosphorus Heterocycles
Authors: Camacho Paula Sanz , Stanford Martin W. , McKay David , Dawson Daniel M. , Athukorala Arachchige Kasun S. , Cordes David B. , Slawin Alexandra M. Z. , Woollins J. Derek , Ashbrook Sharon E.
Published: May 2018

A series of P−E‐containing heterocycles (E=chalcogen) with aromatic backbones were synthesised and characterised by single‐crystal and powder XRD, microanalysis and mass spectrometry. Solution‐ and solid‐state 31P and 77Se NMR spectroscopy revealed significant differences between the NMR parameters in solution and in the solid state, related to conformational changes in the molecules. Many compounds were shown to exhibit a number of different polymorphic structures (identified by single‐crystal XRD), although the bulk material studied by solid‐state NMR spectroscopy often contained just one major polymorph. For the unoxidised heterocycles, the presence of weak intermolecular J couplings was also investigated by DFT calculations.
Reactivity of 3,3,3‐Trifluoropropyne at Rhodium Complexes: Development of Hydroboration Reactions
Authors: von Hahmann Cortney N. , Talavera Maria , Xu Conghui , Braun Thomas
Published: May 2018

The rhodium compounds [Rh(C≡CCF3)(PEt3)3] (2), fac‐[RhH(C≡CCF3)2(PEt3)3] (3), and fac‐[Rh{(E)‐CH=CHCF3}(C≡CCF3)2(PEt3)3] (4) were synthesized by reactions of the rhodium(I) complexes [Rh(H)(PEt3)3] (1) and [Rh(Bpin)(PEt3)3] (5, HBpin=pinacolborane) with the alkyne 3,3,3‐trifluoropropyne. Reactivity studies of [Rh(C≡CCF3)(PEt3)3] (2) were performed with CO and 13CO to form [Rh(C≡CCF3)(CO)(PEt3)3] (7) and subsequently trans‐[Rh(C≡CCF3)(CO)(PEt3)2] (8) as well as the labeled derivatives. Using 1–4 as catalysts, hydroboration reactions selectively afforded borylated building blocks.
A Highly Stable Two‐Dimensional Copper(II) Organic Framework for Proton Conduction and Ammonia Impedance Sensing
Authors: Sun Zhibing , Yu Shihang , Zhao Lili , Wang Jifeng , Li Zifeng , Li Gang
Published: May 2018

This work reports the design and fabrication of a proton conductive 2D metal–organic framework (MOF), [Cu(p‐IPhHIDC)]n (1) (p‐IPhH3IDC=2‐(p‐N‐imidazol‐1‐yl)‐phenyl‐1 H‐imidazole‐4,5‐dicarboxylic acid) as an advanced ammonia impedance sensor at room temperature and 68–98 % relative humidity (RH). MOF 1 shows the optimized proton conductivity value of 1.51×10−3 S cm−1 at 100 °C and 98 % RH. Its temperature‐dependent and humidity‐dependent proton conduction properties have been explored. The large amount of uncoordinated carboxylate groups between the layers plays a vital role in the resultant conductivity. Distinctly, the fabricated MOF‐based sensor displays the required stability toward NH3, enhanced sensitivity, and notable selectivity for NH3 gas. At room temperature and 68 % RH, it gives a remarkable gas response of 8620 % to 130 ppm NH3 gas and lower detection limit of 2 ppm towards NH3 gas. It is also found that the gas response of the ammonia sensor increases linearly with the increase of NH3 gas concentration under 68–98 % RH and room temperature. Moreover, the sensor indicates excellent reversibility and selectivity toward NH3 versus N2, H2, O2, CO, CO2, benzene, and MeOH. Based on structural analyses, activation energy calculations, water and NH3 vapor absorptions, and PXRD determinations, proton conduction and NH3 sensing mechanisms are suggested.
A Novel Linking Strategy of Using 9,10‐Dihydroacridine to Construct Efficient Host Materials for Red Phosphorescent Organic Light‐Emitting Diodes
Authors: Liu Xiang‐Yang , Ma Yu‐Yang , Zhang Wenjuan , Song Bo , Ding Lei , Fung Man‐Keung , Fan Jian
Published: May 2018

Three novel 9,10‐dihydroacridine derivatives, 4′‐(10‐methyl‐9,9‐diphenyl‐9,10‐dihydroacridin‐4‐yl)[1,1′‐biphenyl]‐4‐carbonitrile (MeAcPhCN), 4′‐(9,9,10‐triphenyl‐9,10‐dihydroacridin‐4‐yl)[1,1′‐biphenyl]‐4‐carbonitrile (PhAcPhCN), and 5‐[4‐(9,9,10‐triphenyl‐9,10‐dihydroacridin‐4‐yl)phenyl]picolinonitrile (MeAcPyCN), were prepared by the attachment of [1,1′‐biphenyl]‐4‐carbonitrile or 5‐phenylpicolinonitrile to the 4‐position of 9,10‐dihydroacridine. This special linking strategy limited the conjugation length, maintained the triplet energy, and inhibited the intermolecular charge‐transfer (ICT) characteristics of these compounds. Notably, the enhanced accepting strength of the picolinonitrile segment relative to that of benzonitrile led to relatively strong ICT characteristics, a low energy gap, and a low triplet energy for MeAcPyCN. The thermal, photophysical, electrochemical, and electroluminescent properties of these host materials were studied systematically. Consequently, (acetylacetonato)bis(2‐methyldibenzo[f,h]quinoxaline)iridium(III) [Ir(MDQ)2(acac)]‐based red phosphorescent organic light‐emitting diodes (PHOLEDs) were fabricated with these three host materials. As a result, the device hosted by MeAcPhCN showed good device performance with a maximum external quantum efficiency of 20.5 %.
Synthesis of Dihydroxyalkynyl and Dihydroxyalkyl Nucleotides as Building Blocks or Precursors for Introduction of Diol or Aldehyde Groups to DNA for Bioconjugations
Authors: Krömer Matouš , Bártová Kateřina , Raindlová Veronika , Hocek Michal
Published: May 2018

(3,4‐Dihydroxybut‐1‐ynyl)uracil, ‐cytosine and −7‐deazaadenine 2′‐deoxyribonucleoside triphosphates (dNTPs) were prepared by direct aqueous Sonogashira cross‐coupling of halogenated dNTPs with dihydroxybut‐1‐yne and converted to 3,4‐dihydroxybutyl dNTPs through catalytic hydrogenation. Sodium periodate oxidative cleavage of dihydroxybutyl‐dUTP gave the desired aliphatic aldehyde‐linked dUTP, whereas the oxidative cleavage of the corresponding deazaadenine dNTP gave a cyclic aminal. All dihydroxyalkyl or ‐alkynyl dNTPs and the formylethyl‐dUTP were good substrates for DNA polymerases and were used for synthesis of diol‐ or aldehyde‐linked DNA. The aldehyde linked DNA was used for the labelling or bioconjugations through hydrazone formation or reductive aminations.
The dynamics of a healthy and infected red blood cell in flow through constricted channels: A DPD simulation
Authors: Hoque Sazid Zamal , Anand D. Vijay , Patnaik B. S. V.
Published: May 2018

Understanding the dynamics of red blood cell (RBC) motion under in silico conditions is central to the development of cost‐effective diagnostic tools. Specifically, unraveling the relationship between the rheological properties and the nature of shape change in the RBC (healthy or infected) can be extremely useful. In case of malarial infection, RBC progressively loses its deformability and tends to occlude the microvessel. In the present study, detailed mesoscopic simulations are performed to investigate the deformation dynamics of an RBC in flow through a constricted channel. Specifically, the manifestation of viscous forces (through flow rates) on the passage and blockage characteristics of a healthy red blood cell (hRBC) vis‐á‐vis an infected red blood cell (iRBC) are investigated. A finite‐sized dissipative particle dynamics framework is used to model plasma in conjunction with a discrete model for the RBC. Instantaneous wall boundary method was used to model no‐slip wall boundary conditions with a good control on the near‐wall density fluctuations and compressibility effects. To investigate the microvascular occlusion, the RBC motion through 2 types of constricted channels, viz, (1) a tapered microchannel and (2) a stenosed‐type microchannel, were simulated. It was observed that the deformation of an infected cell was much less compared with a healthy cell, with an attendant increase in the passage time. Apart from the qualitative features, deformation indices were obtained. The deformation of hRBC was sudden, while the iRBC deformed slowly as it traversed through the constriction. For higher flow rates, both hRBC and iRBC were found to undergo severe deformation. Even under low flow rates, hRBC could easily traverse past the constricted channel. However, for sufficiently slow flow rates (eg, capillary flows), the microchannel was found to be completely blocked by the iRBC.
Potential Use of Squarates and Croconates as Singlet Fission Sensitizers
Authors: López‐Carballeira D. , Casanova D. , Ruipérez F.
Published: May 2018

The geometrical and electronic structures of 44 squarate and croconate derivatives are computationally studied by quantum chemistry methods, in the pursuit of new singlet fission sensitizers. A non‐negligible singlet open‐shell diradical character is observed for most of the studied molecules, which can be controlled through chemical substitution as well as by the size of the central ring. Such a diradical character is related to small singlet‐triplet energy gaps, facilitating the accomplishment of the singlet fission energetic requirements. In general, the present results indicate that squarates hold superior singlet fission capabilities than croconates, although we have identified several derivatives within both families as promising singlet fission sensitizers.
Does it pay to be sustainable? Looking inside the black box of the relationship between sustainability performance and financial performance
Authors: Hussain Nazim , Rigoni Ugo , Cavezzali Elisa
Published: May 2018

The last three decades have witnessed a huge amount of research exploring the linkage between companies' sustainability performance (SP), sustainability disclosure and financial performance (FP). Researchers have applied various methods and techniques to investigate this relationship, yet the results remain equivocal. In this article, we look inside this black box by considering various manifestations of sustainability practices and investigating their link with FP. We apply a manual content analysis technique to analyse the sustainability reports of the 100 best‐performing US firms. Our results reveal that fragmentation in the results is caused by the SP measurement. Additionally, we note that the interlinkages between different SP dimensions and sub‐dimensions are weak and somewhat contradictory. The results help draw important policy implications for the development of an SP reporting framework.
Flexible TiO2/SiO2/C Film Anodes for Lithium‐Ion Batteries
Authors: Jiang Ying , Chen Shi , Mu Daobin , Zhao Zhikun , Li Chunli , Ding Zepeng , Xie Chaoxiang , Wu Feng
Published: May 2018

Flexible TiO2/SiO2/C films are prepared by using an electrospinning approach and used as self‐supporting electrodes for lithium‐ion batteries (LIBs), which exhibit excellent high‐rate capability with a capacity of 115.5 mAh g−1 at 8 A g−1 (9.8 C rate) and good storage performance. The LIBs also show high long‐term cycling stability of 700 cycles at 200 mA g−1 with a capacity of 380.1 mAh g−1 and a high capacity retention of 88.3 %. Thus, the TiO2/SiO2/C films have the potential to serve as electrodes for flexible LIBs, owing to their flexibility and excellent electrochemical performance.