bluuebunny/crossref_metadata_2025 huggingface dataset:
Imidazolidinones and Imidazolidine‐2,4‐diones as Antiviral Agents
Authors: Swain Sharada Prasanna , Mohanty Sandeep
Published: January 2019

Imidazolidinones and imidazolidine‐2,4‐diones are important classes of heterocyclic compounds that possess potent activities against several viruses such as dengue virus, enterovirus, hepatitis C virus (HCV), and human immunodeficiency virus (HIV). The first imidazolidinone derivative as an anti‐HIV agent was reported in 1996. Imidazolidinones inhibit HIV aspartic protease activity, and also act as CCR5 co‐receptor antagonists. Significant effort has been devoted to the design of various imidazolidinone analogues that are active against drug‐resistant HIV strains, with fewer side effects. Different scaffolds have been designed through both rational drug design strategies and computer‐aided drug design. Imidazolidinones have been found to be potent against HIV, and preclinical studies are currently in progress. There are some reports of imidazolidinones as having both anti‐HCV and anti‐dengue virus activity, and more research has yet to be done along these lines. These compounds inhibit NS3 serine protease of HCV, and NS2B‐NS3 protease of dengue virus. Pyridyl‐imidazolidinones possess very specific and potent activity against human enterovirus 71 (EV71) by targeting the EV71 capsid protein VP1, and inhibiting viral adsorption and/or viral RNA uncoating.
TAS‐120 Cancer Target Binding: Defining Reactivity and Revealing the First Fibroblast Growth Factor Receptor 1 (FGFR1) Irreversible Structure
Authors: Kalyukina Maria , Yosaatmadja Yuliana , Middleditch Martin J. , Patterson Adam V. , Smaill Jeff B. , Squire Christopher J.
Published: January 2019

1‐[(3S)‐3‐[4‐Amino‐3‐[2‐(3,5‐dimethoxyphenyl)ethynyl]‐1H‐pyrazolo[3,4‐d]pyrimidin‐1‐yl]‐1‐pyrrolidinyl]‐2‐propen‐1‐one (TAS‐120) is an irreversible inhibitor of the fibroblast growth factor receptor (FGFR) family, and is currently under phase I/II clinical trials in patients with confirmed advanced metastatic solid tumours harbouring FGFR aberrations. This inhibitor specifically targets the P‐loop of the FGFR tyrosine kinase domain, forming a covalent adduct with a cysteine side chain of the protein. Our mass spectrometry experiments characterise an exceptionally fast chemical reaction in forming the covalent complex. The structural basis of this reactivity is revealed by a sequence of three X‐ray crystal structures: a free ligand structure, a reversible FGFR1 structure, and the first reported irreversible FGFR1 adduct structure. We hypothesise that the most significant reactivity feature of TAS‐120 is its inherent ability to undertake conformational sampling of the FGFR P‐loop. In designing novel covalent FGFR inhibitors, such a phenomenon presents an attractive strategy requiring appropriate positioning of an acrylamide group similarly to that of TAS‐120.
The role of neuro‐immune interactions in cancer‐related fatigue: Biobehavioral risk factors and mechanisms
Authors: Bower Julienne E.
Published: January 2019

Fatigue is a common and distressing symptom in both patients with cancer and cancer survivors. There is substantial variation in the severity and persistence of cancer‐related fatigue that may be driven by individual differences in host factors, including characteristics that predate the cancer experience as well as responses to cancer and its treatment. This review examines biobehavioral risk factors linked to fatigue and the mechanisms through which they influence fatigue across the cancer continuum, with a focus on neuro‐immune processes. Among psychosocial risk factors, childhood adversity is a strong and consistent predictor of cancer‐related fatigue; other risk factors include history of depression, catastrophizing, lack of physical activity, and sleep disturbance, with compelling preliminary evidence for loneliness and trait anxiety. Among biologic systems, initial work suggests that alterations in immune, neuroendocrine, and neural processes are associated with fatigue. The identification of key risk factors and underlying mechanisms is critical for the development and deployment of targeted interventions to reduce the burden of fatigue in the growing population of cancer survivors. Given the multidimensional nature of fatigue, interventions that influence multiple systems may be most effective.
Risk stratification by somatic mutation burden in Ewing sarcoma
Authors: Liu Kevin X. , Lamba Nayan , Hwang William L. , Niemierko Andrzej , DuBois Steven G. , Haas‐Kogan Daphne A.
Published: January 2019

Background

Up to one‐third of patients with localized Ewing sarcoma (ES) develop recurrent disease, but current biomarkers do not accurately identify this high‐risk group. Therefore, the objective of this study was to determine the utility of mutational burden in predicting outcomes in patients with localized ES.

Methods

Clinical and genomic data from 99 patients with ES, of whom 63 had localized disease at diagnosis, were obtained from the cBioPortal for Cancer Genomics. Genomic data included the type and number of somatic mutations using cBioPortal mutation calling. Primary endpoints were overall survival (OS) and the time to progression (TTP).

Results

Patients had a median number of 11 somatic mutations. Patients were stratified according to whether they had a lower or higher mutational burden if they had ≤11 or >11 mutations, respectively. Higher mutational burden was significantly associated with inferior OS and TTP, a finding that was confirmed by univariate and multivariable analyses. In patients who had localized disease at diagnosis, higher mutational burden was the only variable significantly associated with inferior OS and TTP. The presence of a mutation in either stromal antigen 2 (STAG2) or tumor protein 53 (TP53), both of which were correlated previously with shorter OS in patients with ES, were significantly associated with higher mutational burden. Upon stratifying patients who had localized disease based on a standard panel of cancer genes, higher risk stratification was correlated significantly with inferior TTP and trended toward significance with inferior OS.

Conclusions

Patients who have localized ES and a higher mutational burden have inferior OS and TTP compared with those who have lower mutation burden. The current findings suggest that the somatic mutation burden can be used to better risk stratify these patients and to guide clinical decision making.
Decisional burden among parents of children with cancer
Authors: Sisk Bryan A. , Kang Tammy I. , Goldstein Richard , DuBois James M. , Mack Jennifer W.
Published: January 2019

Background

Despite growing evidence and support for shared decision making, little is known about the experiences of parents who hold more active roles than they wish.

Methods

This was a prospective cohort study of 372 parents of children with cancer and their oncologists at 2 academic pediatric hospitals. Parents were surveyed within 12 weeks of the diagnosis, and they were assessed for associated factors and outcomes of holding a more active decision‐making role than they preferred. Parents were asked about their preferred and actual roles in decision making. Oncologists were asked to estimate parental preferences.

Results

Most parents preferred to share decision making with the oncologist (64% [236 of 372]); however, 13% (49 of 372) preferred oncologist‐led decision making. Most parents fulfilled their ideal decision‐making role (66% [244 of 372]), but a notable minority were either more involved (14% [52 of 372]) or less involved than they preferred (20% [76 of 372];P < .0001 [McNemar test]). Oncologists recognized parents’ preferred roles in 49% of cases (167 of 341); 24% (82 of 341) of parents preferred more active roles than the oncologist recognized, and 27% (92 of 341) preferred less active roles than recognized. No parent or communication characteristics were found that were associated with parents’ holding a more active role than desired in decision making. Parents who held more active roles in decision making than they wished had higher odds of decisional regret (odds ratio, 3.75; 95% confidence interval, 2.07‐6.80;P < .0001).

Conclusions

Although many parents fulfill their desired roles in decision making about their child’s cancer, some are asked to take on more active roles than they wish. Holding a more active role than desired may lead to increased decisional regret.
Tuning the Magnetic Properties of Columnar Benzo[e][1,2,4]triazin‐4‐yls with the Molecular Shape
Authors: Jasiński Marcin , Szymańska Katarzyna , Gardias Anita , Pociecha Damian , Monobe Hirosato , Szczytko Jacek , Kaszyński Piotr
Published: January 2019

A homologous series of disc‐like 1,3,6‐trisubstituted benzo[e][1,2,4]triazin‐4‐yls 1[n] was synthesized and their structural, thermal, optical, magnetic, and electric properties were investigated. The results demonstrate that all members of the series display a Colh phase with clearing temperatures depending on the length of the alkoxy chains at the N(1) position, hence the shape of the disc. Powder XRD and magnetic data indicate a gradual change in the column diameter and magnetic behavior in the series in transition from half‐disc in 1[0] (antiferromagnetic interactions) to full‐disc geometry in the 1[12] homologue (ferromagnetic interactions with J/kB=+7.5 K). Studies of binary systems revealed that a 1 : 1 mixture of 1[0] and 1[12] exhibits modest stabilization of the Colh phase with an expanded range, and magnetic behavior typical for 1[0] in the rigid phase obtained from the melt. Electric measurements demonstrated hole mobility of ∼10−3 cm2 V−1 s−1 and dark conductivity of ∼10−11 Scm−1 in the mixture and individual compounds. The latter is enhanced up to 4 times by simultaneous illumination with UV light.
High‐Performance Photoelectrochemical Water Oxidation with Phosphorus‐Doped and Metal Phosphide Cocatalyst‐Modified g‐C3N4 Formation Through Gas Treatment
Authors: Qin Dong‐Dong , Quan Jing‐Jing , Duan Shi‐Fang , San Martin Jovan , Lin Yixiong , Zhu Xiaolin , Yao Xiao‐Qiang , Su Jin‐Zhan , Rodríguez‐Gutiérrez Ingrid , Tao Chun‐Lan , Yan Yong
Published: January 2019

Graphitic carbon nitride (g‐C3N4) has been widely explored as a photocatalyst for water splitting. The anodic water oxidation reaction (WOR) remains a major obstacle for such processes, with issues such as low surface area of g‐C3N4, poor light absorption, and low charge‐transfer efficiency. In this work, such longtime concerns have been partially addressed with band gap and surface engineering of nanostructured graphitic carbon nitride (g‐C3N4). Specifically, surface area and charge‐transfer efficiency are significantly enhanced through architecting g‐C3N4 on nanorod TiO2 to avoid aggregation of layered g‐C3N4. Moreover, a simple phosphide gas treatment of TiO2/g‐C3N4 configuration not only narrows the band gap of g‐C3N4 by 0.57 eV shifting it into visible range but also generates in situ a metal phosphide (M=Fe, Cu) water oxidation cocatalyst. This TiO2/g‐C3N4/FeP configuration significantly improves charge separation and transfer capability. As a result, our non‐noble‐metal photoelectrochemical system yields outstanding visible light (>420 nm) photocurrent: approximately 0.3 mA cm−2 at 1.23 V and 1.1 mA cm−2 at 2.0 V versus RHE, which is the highest for a g‐C3N4‐based photoanode. It is expected that the TiO2/g‐C3N4/FeP configuration synthesized by a simple phosphide gas treatment will provide new insight for producing robust g‐C3N4 for water oxidation.
A Cobalt‐Free Li(Li0.16Ni0.19Fe0.18Mn0.46)O2 Cathode for Lithium‐Ion Batteries with Anionic Redox Reactions
Authors: Cheng Xiaolu , Wei Hezhuan , Hao Weijian , Li Huiyu , Si Huinan , An Shengli , Zhu Wentao , Jia Guixiao , Qiu Xinping
Published: January 2019

Lithium‐rich, Mn‐based layered oxides Li2MnO3‐LiMO2 (M=Ni, Co) have been considered as promising cathode candidates owing to their high capacity. However, the resources shortage and high price of cobalt make it imperious to substitute cobalt with other high‐abundance elements. Here, we synthesized a low‐cost, cobalt‐free, Fe‐substituted oxide material, Li(Li0.16Ni0.19Fe0.18Mn0.46)O2. It exhibited a high reversible capacity of 169.2 mAh g−1 after 100 cycles and maintained an extraordinarily high discharge potential during cycling. X‐ray photoelectron spectroscopy and DFT calculations revealed that super iron FeIV exists in the delithiated state, and oxygen participates in the redox reaction in addition to the Ni2+/Ni4+ and Fe3+/Fe4+ redox couples. The anionic oxidation preferentially occurred on oxygen with a Li−O−Li configuration and with oxidized Fe and Ni coordination.
Nitrogen‐Doped Carbon‐Supported Nickel Nanoparticles: A Robust Catalyst to Bridge the Hydrogenation of Nitriles and the Reductive Amination of Carbonyl Compounds for the Synthesis of Primary Amines
Authors: Zhang Yangmin , Yang Hanmin , Chi Quan , Zhang Zehui
Published: January 2019

An efficient method was developed for the synthesis of primary amines either from the hydrogenation of nitriles or reductive amination of carbonyl compounds. The reactions were catalyzed by nitrogen‐doped mesoporous carbon (MC)‐supported nickel nanoparticles (abbreviated as MC/Ni). The MC/Ni catalyst demonstrated high catalytic activity for the hydrogenation of nitriles into primary amines in high yields (81.9–99 %) under mild reaction conditions (80 °C and 2.5 bar H2). The MC/Ni catalyst also promoted the reductive amination of carbonyl compounds for the synthesis of primary amines at 80 °C and 1 bar H2. The hydrogenation of nitriles and the reductive amination proceeded through the same intermediates for the generation of the primary amines. To the best of our knowledge, no other heterogeneous non‐noble metal catalysts have been reported for the synthesis of primary amines under mild conditions, both from the hydrogenation of nitriles and reductive amination.
Balancing the Micro‐Mesoporosity for Activity Maximization of N‐Doped Carbonaceous Electrocatalysts for the Oxygen Reduction Reaction
Authors: Du Cheng , Liu Xinlei , Ye Guanghua , Gao Xiaohui , Zhuang Zhihua , Li Ping , Xiang Dong , Li Xiaokun , Clayborne Andre Z. , Zhou Xinggui , Chen Wei
Published: January 2019

Carbonaceous porous structures have instigated global research interest as promising low‐cost electrocatalysts for numerous energy technologies. However, the rational design principle of pore structures for activity maximization is still unclear. In this work, a series of N‐doped carbon (N‐C) catalysts with exclusively different micro‐mesoporosity are investigated for the oxygen reduction reaction (ORR). By combining the experiment results and a pioneering mathematical model, it was observed that the best catalytic activity can only be attained by balancing the micro‐mesoporosity. These findings offer a definite criterion for pore structure optimization in carbon‐based ORR catalysts, which is of great importance for various energy technologies.
The metabolic syndrome and its components are differentially associated with chronic diseases in a high‐risk population of 350 000 adults: A cross‐sectional study
Authors: Rayyan Assi Hana'a , Ziv Arnona , Dankner Rachel
Published: January 2019

Aims

We compared strengths of associations conferred by the metabolic syndrome (MetS) and its components across four chronic disease categories (cancer, cardiovascular diseases [CVDs], chronic kidney disease [CKD], and chronic obstructive pulmonary disease [COPD]) in a community‐dwelling high‐risk population.

Methods

This is a cross‐sectional analysis of Israeli adults insured in a single health maintenance organization during 2010 to 2013 and having greater than or equal to two MetS components (hypertension, dysglycemia, low high‐density lipoprotein level, high plasma triglyceride level, and obesity). Data regarding MetS components, chronic disease prevalence, and sociodemographic variables were retrieved from electronic health records and disease registries.

Results

Among 347 244 eligible members, 54.2% had MetS. MetS was negatively associated with cancer, (prevalence ratio [PR] = 0.86; 95% confidence interval, 0.79‐0.93) and positively associated with CKD (PR = 1.07, [1.01‐1.13]). Some MetS components conferred different associations across the chronic diseases: a high triglyceride level was positively associated with cancer (PR = 1.15, 1.12‐1.18) and CKD (PR = 1.37, 1.32‐1.41) but negatively associated with CVD (PR = 0.88, 0.86‐0.90) and COPD (PR = 0.93, 0.88‐0.98). In the presence of MetS, those with dysglycemia had higher cancer prevalence than those with normoglycemia (PR‐interaction MetS*dysglycemia on cancer = 1.14, 1.06‐1.22). Likewise, in the presence of MetS, men were more likely than women to present with CVD (PR‐interaction MetS*sex on CVD = 1.12, [1.05‐1.20]).

Conclusions

Prevalences of the MetS and MetS components distribute unequally across four chronic diseases. MetS including dysglycemia may warrant screening for cancer, and MetS in males may indicate the presence of CVD. Longitudinal studies may reveal if MetS is associated with different risks or merely indicates better prognosis once having a chronic illness.
Association of diabetes treatment with long‐term glycemic patterns in patients with type 2 diabetes mellitus: A prospective cohort study
Authors: Luo Miyang , Tan Chuen Seng , Lim Wei Yen , Chia Kee Seng , Tang Wern Ee , Tai E. Shyong , Venkataraman Kavita
Published: January 2019

Aim

This study aimed to analyze diabetes treatment and treatment changes in association with long‐term glycemic patterns in an Asian population with diabetes.

Materials and methods

This was a prospective cohort study of 6218 patients with type 2 diabetes managed in public primary care clinics in Singapore. Clinical data from 2011 to 2016 were extracted from electronic medical records, including serial HbA1c measurements and dispensed antidiabetic medication records. Patterns of longitudinal HbA1c trajectories were identified using latent class growth analysis, and patients' annual treatment plans were compared between subgroups with different HbA1c patterns.

Results

We identified four distinct HbA1c patterns. Eighty‐one percent of patients were classified in the low‐stable group, where monotherapy and dual therapy with oral agents were the most common treatments. We also identified three groups with poorer control, with moderate‐stable (14%), moderate‐increase (3%), and high‐decrease (2%) HbA1c patterns. Insulin treatment was most prevalent in these groups, with 61% to 72% of subjects receiving insulin treatment in 2016. More than 60% of subjects in poorer control groups had experienced treatment intensification during follow‐up. Addition of multiple insulin injections was the most common intensification in moderate‐increase and high‐decrease groups.

Conclusions

Treatment reflected and was appropriate to the extent of dysglycemia in this population. A small group of patients had deteriorating glycemic control, in spite of being treated with multiple insulin injections, suggesting non‐response or non‐adherence to treatment. Further investigation is needed to identify reasons for the deteriorating control observed and design effective interventions for these patients.
A Comparative Perspective on Brain Regeneration in Amphibians and Teleost Fish
Authors: Lust Katharina , Tanaka Elly M.
Published: January 2019

Regeneration of lost cells in the central nervous system, especially the brain, is present to varying degrees in different species. In mammals, neuronal cell death often leads to glial cell hypertrophy, restricted proliferation, and formation of a gliotic scar, which prevents neuronal regeneration. Conversely, amphibians such as frogs and salamanders and teleost fish possess the astonishing capacity to regenerate lost cells in several regions of their brains. While frogs lose their regenerative abilities after metamorphosis, teleost fish and salamanders are known to possess regenerative competence even throughout adulthood. In the last decades, substantial progress has been made in our understanding of the cellular and molecular mechanisms of brain regeneration in amphibians and fish. But how similar are the means of brain regeneration in these different species? In this review, we provide an overview of common and distinct aspects of brain regeneration in frog, salamander, and teleost fish species: from the origin of regenerated cells to the functional recovery of behaviors.
A sensor network for substation facility maintenance without device configurations
Authors: Otani Tetsuo , Miyashita Michifumi , Kurono Masahiro , Ishihara Yuji , Tanaka Tatsuji , Nakajima Takashi
Published: January 2019

Maintenance support systems (MSS) monitoring conditions of facilities are indispensable for condition‐based maintenance. A sensor network is used to acquire maintenance data in the MSS, and installation of the sensor network should be simple and easy to execute maintenance tasks in a cost‐effective way. Therefore, this report sets a proposal of an autonomous configuration function of the systems that makes the installation simple and easy. This function is composed of wireless sensor networks, plug‐and‐play function configuring software modules, and cooperative procedure between them. This paper also shows evaluations of the proposed function that is feasible for practical maintenance work. The evaluations have been carried out using a prototype system implementing the elements of the proposed function.
Correlation of native and exotic species richness: a global meta‐analysis finds no invasion paradox across scales
Authors: Peng Shijia , Kinlock Nicole L. , Gurevitch Jessica , Peng Shaolin
Published: January 2019

Support for the “biotic resistance hypothesis,” that species‐rich communities are more successful at resisting invasion by exotic species than are species‐poor communities, has long been debated. It has been argued that native–exotic richness relationships (NERR) are negative at small spatial scales and positive at large scales, but evidence for the role of spatial scale on NERR has been contradictory. However, no formal quantitative synthesis has previously examined whether NERR is scale‐dependent across multiple studies, and previous studies on NERR have not distinguished spatial grain and extent, which may drive very different ecological processes. We used a global systematic review and hierarchical mixed‐effects meta‐analysis to provide a comprehensive quantitative assessment of the patterns of NERR over a range of spatial grain sizes and spatial extents, based on 204 individual cases of observational (non‐experimental) NERRs from 101 publications. We show that NERR was indeed highly scale dependent across studies and increased with the log of grain size. However, mean NERR was not negative at any grain size, although there was high heterogeneity at small grain sizes. We found no clear patterns of NERR across different spatial extents, suggesting that extent plays a less important role in determining NERR than does grain, although there was a complex interaction between extent and grain size. Almost all studies on NERR were conducted in North America, western Europe, and a few other regions, with little information on tropical or Arctic regions. We did find that NERR increased northward in temperate regions and also varied with longitude. We discuss possible explanations for the patterns we found, and caution that our results do not show that invasive species are benign or have no negative consequences for biodiversity preservation. This study represents the first global quantitative analysis of scale‐based NERR, and casts doubt on the existence of an “invasion paradox” of negative NERR at small scales and positive correlations at large scales in non‐experimental studies.
Non‐circular home ranges and the estimation of population density
Authors: Efford M. G.
Published: January 2019

Spatially explicit capture–recapture (SECR) models have emerged as one solution to the problem of estimating the population density of mobile and cryptic animals. Spatial models embody assumptions regarding the spatial distribution of individuals and the spatial detection process. The detection process is modeled in SECR as a radial decline in detection probability with distance from the activity center of each individual. This would seem to require that home ranges are circular. The robustness of SECR when home ranges are not circular has been the subject of conflicting statements. Ivan et al. previously compared the SECR density estimator to a telemetry‐scaled non‐spatial estimator. I suggest that the apparent non‐robustness of SECR in their study was a simulation artefact. New simulations of elliptical home ranges establish that the SECR density estimator is largely robust to non‐circularity when detectors are spread in two dimensions, but may be very biased if the detector array is linear and home ranges align with the array. Transformation to isotropy reduces bias from designs of intermediate dimension, such as hollow square arrays. Possible alignment of home ranges should be considered when designing detector arrays.
The use of diuretics in heart failure with congestion — a position statement from the Heart Failure Association of the European Society of Cardiology
Authors: Mullens Wilfried , Damman Kevin , Harjola Veli‐Pekka , Mebazaa Alexandre , Brunner‐La Rocca Hans‐Peter , Martens Pieter , Testani Jeffrey M. , Tang W.H. Wilson , Orso Francesco , Rossignol Patrick , Metra Marco , Filippatos Gerasimos , Seferovic Petar M. , Ruschitzka Frank , Coats Andrew J.
Published: January 2019

The vast majority of acute heart failure episodes are characterized by increasing symptoms and signs of congestion with volume overload. The goal of therapy in those patients is the relief of congestion through achieving a state of euvolaemia, mainly through the use of diuretic therapy. The appropriate use of diuretics however remains challenging, especially when worsening renal function, diuretic resistance and electrolyte disturbances occur. This position paper focuses on the use of diuretics in heart failure with congestion. The manuscript addresses frequently encountered challenges, such as (i) evaluation of congestion and clinical euvolaemia, (ii) assessment of diuretic response/resistance in the treatment of acute heart failure, (iii) an approach towards stepped pharmacologic diuretic strategies, based upon diuretic response, and (iv) management of common electrolyte disturbances. Recommendations are made in line with available guidelines, evidence and expert opinion.
Tailored Assembly of Molecular Water Oxidation Catalysts on Photoelectrodes for Artificial Photosynthesis
Authors: Bae Sanghyun , Jang Ji‐Eun , Lee Hyun‐Wook , Ryu Jungki
Published: January 2019

Solar‐to‐chemical energy conversion, or so‐called artificial photosynthesis, is a promising technology enabling sustainable production and use of various chemical compounds such as H2, CO, CH4, HCOOH, CH3OH, and NH3. For practical applications, it is necessary to improve the interfacial properties of light‐harvesting semiconductors through modification with proper electrocatalysts, by trying to overcome their intrinsic limitations such as rapid recombination, sluggish reaction kinetics, and photocorrosion. Compared to their heterogeneous counterparts, molecular electrocatalysts have a higher catalytic activity and more flexibility in their design/synthesis and integration with semiconducting materials. In this article, we review recent efforts on the tailored assembly of molecular electrocatalysts to address the above issues for artificial photosynthesis, especially those for oxygen evolution reactions on semiconductor photoelectrodes for photoelectrochemical water oxidation. One can expect that the strategies and methods developed for the tailored assembly and integration of molecular electrocatalysts on water oxidation photoanodes can provide insights for the design and fabrication of various forms of photosynthetic devices due to the similarity between their underlying principles.
Reactivity of Polyynes: Complex Molecules from Simple Carbon Rods
Authors: Pigulski Bartłomiej , Gulia Nurbey , Szafert Sławomir
Published: January 2019

Polyynes are linear carbon rods that may be regarded as models of carbyne – still elusive linear allotropic form of carbon. This microreview addresses the use of polyynes as synthetic precursors of complex organic and organometallic compounds. Application of such unusual molecules as starting materials for various chemical transformations leads to products which often are not easily accessible using “traditional“ approaches. Polyynes may for instance be used in the synthesis of molecular wires, materials possessing high nonlinear optical response, complex donor–acceptor systems, solvatochromic fluorescent dyes or natural products. The most significant challenge here is to control the regioselectivity of a transformation of such linear sp‐hybridized carbon chains. The impact of steric and electronic properties of reagents on the reaction pattern is hence highly important and will be discussed. Moreover, the transformations of end‐groups will also be addressed since their reactivity might very often be different than that of acetylenes.
The synthesis of 9‐O‐Methylpaepalantine and Dehydroxanthomegnin: Related Isocoumarin‐Containing Natural Products
Authors: Sumani Jimmy E. Y. , Ngwira Kennedy J. , Lemmerer Andreas , de Koning Charles B.
Published: January 2019

The first synthesis of two related isocoumarin‐containing natural products, 9‐O‐methylpaepalantine and dehydroxanthomegnin is described. Commencing with 2,4‐dimethoxybenzaldehyde and utilizing the Stobbe reaction as a key step resulted in the formation of the required naphthalene containing compound, ethyl 4‐acetoxy‐3‐allyl‐6,8‐dimethoxynaphthalene‐2‐carboxylate. O‐Allylation of 4‐hydroxy‐6,8‐dimethoxynaphthalene‐2‐carboxylate followed by a Claisen rearrangement afforded the naphthol, ethyl 3‐allyl‐4‐hydroxy‐6,8‐dimethoxynaphthalene‐2‐carboxylate. Introduction of a methoxy substituent onto the 1‐position of the naphthalene nucleus utilizing a PIFA‐mediated method afforded, after O‐methylation, ethyl 3‐allyl‐1,4,6,8‐tetramethoxynaphthalene‐2‐carboxylate. Reduction of the ester was followed by oxidation to the aromatic acid, utilizing firstly a PCC oxidation and then a Pinnick oxidation to afford 3‐allyl‐1,4,6,8‐tetramethoxynaphthalene‐2‐carboxylic acid. Wacker oxidation of the aromatic acid resulted in the formation of 5,7,9,10‐tetramethoxy‐3‐methyl‐1H‐benzo[g]isochromen‐1‐one, which was then converted into 9‐O‐methylpaepalantine by treatment with boron trichloride. Utilizing similar synthetic methodology dehydroxanthomegnin was synthesized in thirteen steps commencing from 2,4,5‐trimethoxybenzaldehyde in an overall yield of 1.3 %.
SN2 Reaction of Diarylmethyl Anions at Secondary Alkyl and Cycloalkyl Carbons
Authors: Shinohara Riku , Ogawa Narihito , Kawashima Hidehisa , Wada Kyohei , Saito Shun , Yamazaki Takashi , Kobayashi Yuichi
Published: January 2019

The substitution reaction of the diethyl allylic and propargylic phosphates with Ar2CH anions was applied to sec‐alkyl phosphates to compare reactivity and stereoselectivity. However, the substitution took place on the ethyl carbon of the diethyl phosphate group. We then found that the diphenyl phosphate leaving group ((PhO)2PO2) was suited for the substitution at the sec‐alkyl carbon. Enantioenriched diphenyl sec‐alkyl phosphates with different substituents (Me, Et, iPr) on the vicinal position underwent the substitution reaction with almost complete inversion (>99% enantiospecificity). The substitution reactions of cyclohexyl phosphates possessing cis or trans substituents (Me and/or tBu) at the C4, C3, and C2 positions of the cyclohexane ring were also studied to observe the difference in reactivity among the cis and trans isomers. A transition‐state model with the phosphate leaving group ((PhO)2PO2) in the axial position was proposed to explain the difference. This model was supported by computational calculation of the virtual substitution reaction of the structurally simpler “dimethyl” cyclohexyl phosphates (leaving group = (MeO)2PO2) with MeLi. Furthermore, the calculation unexpectedly indicated higher propensity of (PhO)2PO2 as a leaving reactivity than alkyl phosphate groups such as (MeO)2PO2 and (iPrO)2PO2.
Oleic Acid Based Cyclodextrins for the Development of New Hydrosoluble Amphiphilic Compounds
Authors: Cocq Aurélien , Rousseau Cyril , Bricout Hervé , Oliva Estefanía , Bonnet Véronique , Djedaïni‐Pilard Florence , Monflier Eric , Tilloy Sébastien
Published: January 2019

A new family of amphiphilic cyclodextrins produced from oleic acid derivatives and maleic anhydride is described. These amphiphilic cyclodextrins are synthesized in two steps. The first step is the alkenylation of maleic anhydride by oleic acid derivatives to produce the oleic succinic anhydrides. The second step is the grafting of the oleic succinic anhydrides on various cyclodextrins. A self‐inclusion of the alkyl chain or an inclusion of one alkyl chain in the cavity of another CD is showed by NMR experiments. The twelve amphiphilic cyclodextrins described possess high solubility in water (50–500 g/L at 20 °C) and low critical aggregation concentration (16–360 mg/L).
Reactions of Trifluoroacetyl Alkynes Under Electrophilic Activation with Brønsted Acids or Acidic Zeolites
Authors: Nursahedova Selbi K. , Ryabukhin Dmitry S. , Muzalevskiy Vasily M. , Iakovenko Roman O. , Boyarskaya Irina A. , Starova Galina L. , Nenajdenko Valentine G. , Vasilyev Aleksander V.
Published: January 2019

The reaction of trifluoroacetyl alkynes [ArC≡C(C=O)CF3] with H2SO4 or TfOH affords products of addition of the acids to the acetylene bond. Hydrolysis of these adducts results in the formation of the corresponding 1,3‐diketones existing in form of enols [Ar(HO)C=CH(C=O)CF3] in up to 98 % yield. The application of less acidic TfOH‐pyridine system permits transformation of these alkynes into the corresponding vinyl triflates in up to 76 % yield. Moreover, this reaction is totally stereoselective to give only Z‐configured vinyl triflates. The reaction of trifluoroacetyl alkynes with arenes in TfOH or under the action of acidic HUSY zeolites CBV‐720 gives rise to 1,3‐diaryl‐1‐CF3‐indenes in up to 81 % yield. Electronic characteristics of initial intermediate mono‐ and dicationic species derived from such alkynes in the highly acidic media were studied by DFT calculations. Plausible cationic reaction mechanism was proposed.
Preparation of RS‐Substituted 1‐(Thiazo‐2‐ylazo)‐naphthalenes by Nucleophilic Substitution of Chlorine with Mercaptans
Authors: Yu Xiuling , Metz Peter , Hartmann Horst
Published: January 2019

Nucleophilic substitution reactions of 4‐chloro‐1‐(thiazo‐2‐ylazo)naphthalenes and 8‐chloro‐5‐(thiazo‐2‐ylazo)quinolines with mercaptans RSH yield not only the desired 4‐RS‐substituted 1‐(thiazo‐2‐ylazo)‐naphthalenes or 8‐RS‐substituted 5‐(thiazo‐2‐ylazo)quinolines, respectively, but also products with multiple RS substituents linked at the naphthalene, quinoline and thiazole moieties. The new RS‐substituted hetarylazo compounds exhibit a deep colour due to their intense long wavelength absorptions in the visible spectral region.
Facile Diastereoselective Synthesis of Highly Substituted Alkylene‐oxetanes from 3‐Alkyl Allenoates and Diaryl 1,2‐Diones/α‐Ketoamides Mediated by DBU
Authors: Krishnan Jagadeesh , Mayadevi T. S. , Varughese Sunil , Nair Vijay
Published: January 2019

A facile tertiary amine‐mediated [2+2] annulation reaction of 3‐alkyl allenoates, and diaryl 1,2‐diones leading to diastereoselective synthesis of highly substituted alkylene‐oxetane derivatives is reported. The reaction was further extended to α‐ketoamides. The obtained amide‐appended oxetanes were transformed to 5‐methylene‐1H‐pyrrol‐2(5H)‐one derivatives with potential biological activity.
Molecular Solar Thermal Energy Storage Systems with Long Discharge Times Based on the Dihydroazulene/Vinylheptafulvene Couple
Authors: Mogensen Josefine , Christensen Oliver , Kilde Martin Drøhse , Abildgaard Martin , Metz Lotte , Kadziola Anders , Jevric Martyn , Mikkelsen Kurt V. , Nielsen Mogens Brøndsted
Published: January 2019

Molecular solar thermal energy storage (MOST) systems based on photochromic molecules that undergo photoisomerization to high‐energy isomers are attractive for storage of solar energy in a closed‐energy cycle. One challenge is to control the discharge time of the high‐energy isomer. Here we show that incorporation of a strong acceptor substituent in the seven‐membered ring of the dihydroazulene/vinylheptafulvene (DHA/VHF) couple increases the half‐life of the energy‐releasing VHF‐to‐DHA back‐reaction from hours to more than a day in a polar solvent. For some derivatives, the absorption maximum of the photo‐active DHA is also significantly redshifted, thereby better matching the solar spectrum. Synthetic protocols and kinetics studies are presented together with a computational study of the energy densities of the systems and excitation spectra. The computations show that the increased lifetime of the high‐energy isomer is counter‐balanced by a lower energy storage capacity in vacuo than for the parent system, but a slightly higher energy density than for the parent system in a polar solvent.
RuII‐Catalysed Regioselective C–N Bond Formation of Indolines and Carbazole with Acyl Azides
Authors: Banerjee Sonbidya , De Pinaki Bhusan , Pradhan Sourav , Shah Tariq A. , Punniyamurthy Tharmalingam
Published: January 2019

RuII‐catalysed pyrimidine directed coupling of the C‐7 C–H bond of indolines with acyl azides as a nitrogen surrogate has been developed to produce acyl amides at room temperature. The reaction of aryl, heteroaryl and α,β‐unsaturated acyl azides can be accomplished in good yields. The procedure can be extended to the C1‐amidation of carbazole with moderate yields. The substrate scope, use of less expensive Ru‐catalysis, and oxidant‐free conditions are the significant practical features.
Synthesis and Photochromic Properties of Azobenzene‐Derived Glycomacrolactones
Authors: Lin Chaoqi , Maisonneuve Stéphane , Theulier Cyril , Xie Juan
Published: January 2019

Reversible photocontrol of glycosides and glycoconjugates structures is a very attractive approach to modulate, in a spatiotemporal way, the various properties and biological activities of carbohydrates. We have synthesized three new azobenzene‐derived glycomacrolactones from thioglycopyranosides. The synthesized cyclic glycoazobenzenes can be reversibly photoisomerized between E and Z isomers with high fatigue resistance. A 1H NMR spectroscopic study shows that E → Z isomerization of glycomacrocycles induces large conformational change of the macrocyclic structures, without changing sugar 4C1 chair conformation. The Z‐glycoazobenzenes can be thermally converted back to the E‐isomers. Interestingly, these 16 to 17‐membered Z‐glycomacrolactones display higher thermal stability than the reported macrocyclic azobenzenes, the half‐life varying from 37 to 72 days. The excellent photoswitching property and bistability of the synthesized glycoazobenzenes open a new opportunity for the convergent synthesis of diastereomers of glycomacrocycles. Furthermore, chiroptical properties have been observed for both E and Z glycomacrolactones. The geometry of different isomers of macrocycles has been optimized with DFT calculations. Theoretical CD spectra obtained by TD‐DFT suggest that the E and Z glycomacrocycles adopt preferentially (P) helical structure for the azobenzene moiety.
Greener Preparation of 5‐Ethyl‐4a‐hydroxyisoalloxazine and Its Use for Catalytic Aerobic Oxygenations
Authors: Oonishi Takahiro , Kawahara Takayuki , Arakawa Yukihiro , Minagawa Keiji , Imada Yasushi
Published: January 2019

Isoalloxazine ring systems are found in flavin cofactors in nature, and the simulation of their redox catalyses is an important task for developing sustainable catalytic oxidation reactions. Although 5‐ethyl‐4a‐hydroxyisoalloxazines are among the most promising candidates as catalyst for such purposes, the use of them for laboratorial as well as industrial synthetic chemistry has so far been quite limited presumably due to the lack of their preparation methods readily, safely, and inexpensively available. In this communication, we introduce an environmentally benign and practical preparation of 5‐ethyl‐4a‐hydroxy‐3,7,8,10‐tetramethylisoalloxazine (1EtOH) from 3,7,8,10‐tetramethylisoalloxazine (1), in which conventional synthetic requirements, including (i) operations under inert conditions, (ii) risky or expensive chemicals, and (iii) isolation of labile intermediates, have all been dissolved. In addition, we have presented that 1EtOH could be an effective catalyst for Baeyer–Villiger oxidation as well as sulfoxidation with molecular oxygen (O2) as a terminal oxidant under suitable conditions, which is the first report on aerobic oxygenations catalyzed by 5‐alkyl‐4a‐hydroxyisoalloxazines.
The effect of cyclic variation of shear stress on non‐cohesive sediment stabilization by microbial biofilms: the role of ‘biofilm precursors’
Authors: Chen Xindi , Zhang Changkuan , Paterson David M. , Townend Ian H. , Jin Chuang , Zhou Zeng , Gong Zheng , Feng Qian
Published: January 2019

Biofilm mediated intertidal sediments exhibit more complex erosional behaviour than abiotic systems. A major feature of intertidal systems is the exposure to repeated cycles of high and low shear created by tidal conditions and also less predictable episodic events, such as storms. There is very little information on how biofilm‐forming communities respond to these conditions. In this study, the effects of both single and repeated‐cycles of shear on the stability of newly developed bio‐sedimentary beds was examined. Cleaned sand, without any potential biostabilization, was used as the control. For the single‐cycle scenario, biofilms were incubated on a non‐cohesive sandy bed under prolonged low shear periods varying between 5 and 22 days, after which erosional stress was applied. No significant biostabilization was observed for the youngest bio‐sedimentary bed (after five days of low shear incubation). After 22 days, microbial communities were characterized by a firmly attached surface biofilm. To cause erosion, greater hydrodynamic stress (0.28 Pa) was required. The erosional behaviour of the underlying sand was also affected in that bedform ripples noted in the control system were no longer observed. Instead, a sudden ‘mass erosion’ took place (0.33 Pa). The one‐cycle scenario indicated that significant biostabilization of sand only occurred after a relative long calm period. Under repeated cycles of stress (five days of low stress followed by high stress event and re‐incubation, repeated for four cycles = 20 days), frequent cyclic disturbance did not degrade the system stability but enhanced biostabilization. The properties of the sub‐surface sediments were also affected where erosion rates were further inhibited. We hypothesize that organic material eroded from the bed acted as a ‘biofilm precursor’ supporting the development of new biofilm growth. A conceptual framework is presented to highlight the dynamics of bio‐sedimentary beds and the effects of growth history under repeated‐cycles. © 2019 John Wiley & Sons, Ltd.
Diesel Exhaust Emission Soot Coated Pyroelectric Materials for Improved Thermal Energy Harvesting
Authors: Azad Puneet , Sharma Moolchand , Vaish Rahul
Published: January 2019

Pyroelectric performance is significantly improved using a coating of diesel exhaust soot. Coated pyroelectric sample (lead zirconate titanate) is exposed to a temporal temperature gradient. Under the application of infrared (IR) heating for a given temperature gradient, the maximum open circuit voltage improves more than four times, electric current across a resistance of 10 ohm improves more than six times, and the stored energy in 10 µF capacitor is enhanced by 17 times. These results are important from two aspects: 1) utilization of waste diesel exhaust soot and 2) improving energy harvesting performance of pyroelectric materials.
Discovering heritable modes of MEG spectral power
Authors: Leppäaho Eemeli , Renvall Hanna , Salmela Elina , Kere Juha , Salmelin Riitta , Kaski Samuel
Published: January 2019

Brain structure and many brain functions are known to be genetically controlled, but direct links between neuroimaging measures and their underlying cellular‐level determinants remain largely undiscovered. Here, we adopt a novel computational method for examining potential similarities in high‐dimensional brain imaging data between siblings. We examine oscillatory brain activity measured with magnetoencephalography (MEG) in 201 healthy siblings and apply Bayesian reduced‐rank regression to extract a low‐dimensional representation of familial features in the participants' spectral power structure. Our results show that the structure of the overall spectral power at 1–90 Hz is a highly conspicuous feature that not only relates siblings to each other but also has very high consistency within participants' own data, irrespective of the exact experimental state of the participant. The analysis is extended by seeking genetic associations for low‐dimensional descriptions of the oscillatory brain activity. The observed variability in the MEG spectral power structure was associated with SDK1 (sidekick cell adhesion molecule 1) and suggestively with several other genes that function, for example, in brain development. The current results highlight the potential of sophisticated computational methods in combining molecular and neuroimaging levels for exploring brain functions, even for high‐dimensional data limited to a few hundred participants.
Critical role of glutamatergic and GABAergic neurotransmission in the central mechanisms of theta‐burst stimulation
Authors: Li Cheng‐Ta , Huang Ying‐Zu , Bai Ya‐Mei , Tsai Shih‐Jen , Su Tung‐Ping , Cheng Chih‐Ming
Published: January 2019

Theta‐burst stimulation (TBS) is a varied form of repetitive transcranial magnetic stimulation (rTMS) and has more rapid and powerful effects than rTMS. Experiments on the human motor cortex have demonstrated that intermittent TBS has facilitatory effects, whereas continuous TBS has inhibitory effects. Huang's simplified model provides a solid basis for elucidating such after‐effects. However, evidence increasingly indicates that not all after‐effects of TBS are as expected, and high variability among individuals has been observed. Studies have suggested that the GABAergic and glutamatergic neurotransmission play a vital role in the aforementioned after‐effects, which might explain the interindividual differences in these after‐effects. Herein, we reviewed the latest findings on TBS from animal and human experiments on glutamatergic and GABAergic neurotransmissions in response to TBS. Furthermore, an updated theoretical model integrating glutamatergic and GABAergic neurotransmissions is proposed.
Glare‐limited appearances in HDR images
Authors: Silzars Aris , Rizzi Alessandro , McCann John J.
Published: January 2019

Intraocular glare and simultaneous contrast control appearance in high‐dynamic‐range (HDR) images. Unique test targets that simulate real images are described. These targets change the HDR range by 500 times, without significantly changing the veiling glare on the retina. These targets also have a nearly constant simultaneous contrast. The range of appearances possible from HDR images with different average luminances were measured. The targets displayed a maximum luminance range of 5.4 log units. Using magnitude estimates (MagEst) of appearances, the relationship between luminance and lightness from white to black was measured. With one exception, only small changes in appearance with large changes in dynamic range were found. It was also found that appearance was scene‐dependent. The same dark grays (MagEst = 10) were observed with luminances of 10, 4.2, 1.1, and 0.063, depending on the percentage of white area in the surround. Glare from more white increases the retinal luminance of the test areas. Simultaneous contrast counteracts glare by making the appearance range (white–black) with a much smaller range of luminances. Appearance is controlled by both the optical scattered light and the spatial processing. A single tone‐scale function of luminance cannot describe appearance controlled by scatter and spatial processing.