bluuebunny/crossref_metadata_2025 huggingface dataset:
Histórias de vida na perspectiva da profissão docente e da gestão em sala de aula
Authors: Lima Severino Roberto
Published: April 2018

Neste artigo apresentam-se resultados referentes à pesquisa sobre a história de vida de professores que lecionam matemática: sua infância enquanto aluno, suas relações e concepções com a matemática e a escolha da profissão docente. Trata-se de uma pesquisa bibliográfica e de campo com professores do Ensino Fundamental II do Colégio Estadual Criança Esperança, localizado em Palmas, Estado do Tocantins. Realizamos entrevistas semiestruturadas com três professoras utilizando a metodologia da História Oral. Os resultados mostram que essas professoras, nascidas no interior, estudaram em escolas públicas, já possuíam alguma relação de proximidade desde a infância com a disciplina, demonstravam habilidades cognitivas e raciocínio lógico e que, possivelmente, esse fator tenha influenciado na escolha da profissão.Palavras-chave: educação matemática; profissão docente; gestão.
Controle da atividade docente e esforço conciliatório: a política de avaliação externa interpretada em uma escola da rede municipal do Rio de Janeiro
Authors: Nazareth Henrique Dias Gomes de
Published: April 2018

Este artigo versa sobre as influências da avaliação externa na prática escolar. Adotaram-se procedimentos metodológicos qualitativos, com vistas a articular pesquisa de campo com análise documental, apoiando-se no referencial teórico analítico conhecido como ciclo de políticas. A sala de aula que abrigou a pesquisa sofria interferências externas provenientes não só das provas, mas também dos cadernos pedagógicos e cobranças dos responsáveis pelos alunos. Essas interferências apareciam de diferentes maneiras, de modo que se transformavam, em alguns momentos, de acordo com o interesse da professora. Em outras situações modificavam a maneira como ela desejaria ocupar o tempo escolar, e, na maioria das vezes, os dois processos, ao mesmo tempo, o que demandava um esforço conciliatório.Palavras-chave: avaliação externa; prática escolar; política educacional.
Development of the athlete sleep behavior questionnaire: A tool for identifying maladaptive sleep practices in elite athletes
Authors: Driller Matthew W , Mah Cheri D , Halson Shona L
Published: April 2018

Introduction: Existing sleep questionnaires to assess sleep behaviors may not be sensitive in determining the unique sleep challenges faced by elite athletes. The purpose of the current study was to develop and validate the Athlete Sleep Behavior Questionnaire (ASBQ) to be used as a practical tool for support staff working with elite athletes.

Methods: 564 participants (242 athletes, 322 non-athletes) completed the 18-item ASBQ and three previously validated questionnaires; the Sleep Hygiene Index (SHI), the Epworth Sleepiness Scale (ESS) and the Pittsburgh Sleep Quality Index (PSQI). A cohort of the studied population performed the ASBQ twice in one week to assess test-retest reliability, and also performed sleep monitoring via wrist-actigraphy.

Results: Comparison of the ASBQ with existing sleep questionnaires resulted in moderate to large correlations (r=0.32 - 0.69). There was a significant difference between athletes and non-athletes for the ASBQ global score (44±6vs. 41±6, respectively,p<0.01) and for the PSQI, but not for the SHI or the ESS. The reliability of the ASBQ was acceptable (ICC=0.87) when re-tested within 7 days. There was a moderate relationship between ASBQ and total sleep time (r=-0.42).

Conclusion: The ASBQ is a valid and reliable tool that can differentiate the sleep practices between athletes and non-athletes, and offers a practical instrument for practitioners and/or researchers wanting to evaluate the sleep behaviors of elite athletes. The ASBQ may provide information on areas where improvements to individual athletes’ sleep habits could be made.
Acute response to 7-day therapy with CPAP in patients with moderate to severe obstructive sleep apnea and cardiac arrhytmia
Authors: Campos Jerónimo , Ernst Glenda , Blanco Magali , Cassano Alejandra , Tello-Santa-Cruz Iván , Cáceres-Monié Cesar , Muyran Alexys , Cansonieri Romina , Salvado Alejandro , Borsini Eduardo
Published: April 2018

Introduction: Obstructive Sleep Apnea (OSA) has been associated with an elevated risk of cardiac arrhythmia. Continuous positive airway pressure (CPAP) is the selected treatment for moderate to severe OSA and could improve arrhythmias in the long term. However, the acute effect of CPAP has not been studied in detail.

Methods: We conducted a prospective study with 25 patients with moderate to severe OSA diagnosed by home respiratory polygraphy (RP) and arrhythmia and/or pauses in 24-hour Holter ECG. We analyzed inflammatory parameters and the rate of arrhythmias/pauses after 7 days of auto-adjusting CPAP.

Results: 92.5% of the patients were men with a mean age of 61.7±1.9 years. Body mass index (BMI) was 59.5±2.2 kg/m2, with a mean apnea hypopnea index (AHI) of 37.7±3.8 events/hour (ev/h), and a residual AHI (AHIr) of 5.3±0.53 ev/h. After short treatment with CPAP we observed a tendency to improvement in both the severity and number of ventricular extrasystoles (VE) (1595.0±850.3 vs. 926.4±434.5 respectively), pauses and the inflammatory parameters (CRP 3.9±3.1 vs. 1.7±1.2, glycemia 131.4±11.6 vs. 121.9±9.8, HOMA 24.4±3.1 vs.21.7±2.8, insulin 7.6±1.4 vs. 7.2±1.2 (p>0.5).

Conclusion: We didn't find significant changes in pauses, VE and inflammatory parameters with CPAP short therapy in CPAP naive patients recently diagnosed with OSA.
Naphthalene [BAT Value Documentation, 2018]
Authors: Klotz K. , Drexler H. , Hartwig A. ,   MAK Commission
Published: April 2018

The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has evaluated a BAR (“Biologischer Arbeitsstoff Referenzwert”) for naphthalene, considering 1‐ and 2‐naphthol in urine to characterize the internal exposure. Naphthalene is classified in category 2 for carcinogenic substances and designated with an “H” because of its contribution to the toxicological hazards due to penetration through the skin in vitro and dermal absorption in vivo.

In a number of biomonitoring studies, the excretion of 1‐ and 2‐naphthol in urine of persons occupationally not exposed to naphthalene was examined. Tobacco smoking affects the naphthol excretion significantly, thus non‐smokers and smokers have to be considered separately. Up to now, no data of representative collectives of the German general population are available. Therefore, the largest German study was considered for the evaluation, where urine samples of 95 non‐smokers were analysed and a 95th percentile for the sum of 1‐ and 2‐naphthol (after hydrolysis) of 33.6 µg/l (30.6 µg/g creatinine) was found. These results are in good accordance with other national and international studies. Therefore, a BAR of 35 µg 1‐ plus 2‐naphthol (after hydrolysis)/l urine was evaluated for non‐smokers. Sampling time is at the end of exposure or the end of the working shift and after long term exposure at the end of the working shift after several shifts. For the interpretation of the result, the smoking status of the persons has to be considered. In case of an occupational co‐exposure to other polycyclic aromatic hydrocarbons (PAH), the analysis of additional PAH‐metabolites is recommended (see MAK Documentation “Polycyclic Aromatic Hydrocarbons”).
1‐Ethoxy‐2‐propylacetat [MAK Value Documentation in German language, 2018]
Authors: Hartwig A. ,   MAK Commission
Published: April 2018

The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated the maximum concentration at the work place (MAK value), the Pregnancy Risk Group and absorption through the skin of 1‐ethoxy‐2‐propyl acetate [
54839‐24‐6
].

1‐Ethoxy‐2‐propyl acetate is weakly irritating to the skin and eyes of rabbits. The critical effect is CNS depression after repeated inhalative exposure with a NOAEC of 100 ml/m
3
in a 28‐day study with rats. Based on this, the maximum concentration at the work place (MAK value) for 1‐ethoxy‐2‐propyl acetate is set at 20 ml/m
3
(120 mg/m
3
). This value also protects against possible irritation, as local effects are not observed up to 1200 ml/m
3
in the 28‐day rat inhalation study.

Since the critical effect of 1‐ethoxy‐2‐propyl acetate is systemic, Peak Limitation Category II is retained. There are still no specific toxicokinetic data available, so that the default excursion factor of 2 is also retained.

There are no data on reproduction toxicity with 1‐ethoxy‐2‐propyl acetate available. 1‐Ethoxy‐2‐propyl acetate remains assigned to Pregnancy Risk Group C in analogy to 1‐ethoxy‐2‐propanol. On the basis of data with 1‐ethoxy‐2‐propanol and other glycol ether acetates, skin contact is expected to contribute significantly to systemic toxicity and 1‐ethoxy‐2‐propyl acetate is designated with “H”.
2‐Methoxypropylacetat‐1 [MAK Value Documentation in German language, 2018]
Authors: Hartwig A. ,   MAK Commission
Published: April 2018

The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated the maximum concentration at the workplace (MAK value) for 2‐methoxypropylacetate‐1 [
70657‐70‐4
]. Available publications and unpublished study reports are described in detail.

Critical effects of 2‐methoxypropylacetate‐1 are its irritancy and teratogenicity. A MAK value of 5 ml/m
3
had been set. This value is now reaffirmed based on the findings on the irritancy of the substance in a 28‐day inhalation study with rats.

Since a local effect is critical, Peak Limitation Category I with excursion factor of 2 has been set. 2‐Methoxypropylacetate‐1 remains assigned to Pregnancy Risk Group B and it also remains designated with an “H” (for substances that can be absorbed through the skin in toxicologically relevant amounts).
Reactive and proactive aggression as meaningful distinctions at the variable and person level in primary school‐aged children
Authors: Carroll Annemaree , McCarthy Molly , Houghton Stephen , Sanders O'Connor Emma , Zadow Corinne
Published: April 2018

Reactive and proactive aggression is a dichotomous classification of aggression in adults and children. This distinction has been supported by a number of variable‐based and factor analytic studies. Due to high inter‐correlations, however, the reactive—proactive aggression distinction may not be entirely useful for understanding how group or individual aggressive behavior varies in children and adolescents. Drawing on a sample of primary school‐aged children (N = 242) aged 7–12 years, this study sought to determine whether reactive and proactive aggression could be distinguished at the variable‐level and the person‐level in children. Exploratory Factor Analysis of data from an aggression instrument measuring both functions and forms of aggression, found a two‐factor construct of aggression constituted by a reactive and proactive aggression factor. A person‐based analysis was then conducted after classifying children according to the presence of reactive and/or proactive aggression. Discriminant function analysis was used to discern whether classifications on the basis of aggression function produced meaningful distinctions in terms of antisocial traits and emotional valence and intensity measures. Two functions were identified which distinguished children with different combinations of reactive and proactive aggression. Reactive‐only aggressive children were defined primarily by high levels of impulsivity, while proactive‐only children were defined primarily by higher levels of antisocial traits. Children high in both types of aggression exhibited both the presence of antisocial traits and impulsivity. Contrary to recent findings, this suggests that differences in aggression functions remain meaningful at the person level in children. Implications for interventions are discussed.
Nanoparticles of Chlorin Dimer with Enhanced Absorbance for Photoacoustic Imaging and Phototherapy
Authors: Zheng Xiaohua , Wang Lei , Liu Shi , Zhang Wei , Liu Feng , Xie Zhigang
Published: April 2018

Nanoparticle assembled from organic molecules is a versatile platform to integrate various functionalities for theranostics. In this work, nanoparticles are constructed from chlorin dimers that are synthesized by reducing porphyrin molecules. Chlorin dimers can assemble into nanoscale aggregates in the absence of surfactants or other auxiliary agent. The resulting nanoparticles of chlorin dimer exhibit much higher absorbance than the porphyrin counterparts, resulting in enhanced photodynamic and photothermal activity upon irradiation. The forming nanoparticles can be effectively endocytosed by the tumor cells, inducing apoptosis under irradiation. Tumor growth on mice model is inhibited by the photodynamic and photothermal treatment in vivo. Furthermore, this nanoparticle can be used for photoacoustic imaging. It is believed that the integrated imaging and phototherapeutic capability in one nanoparticle is beneficial for future cancer diagnosis, therapy, and molecular imaging.
Liquid Exfoliation of Icosahedral Quasicrystals
Authors: Yadav Thakur Prasad , Woellner Cristiano F. , Sinha Shyam K. , Sharifi Tiva , Apte Amey , Mukhopadhyay Nilay Krishna , Srivastava Onkar Nath , Vajtai Robert , Galvao Douglas S. , Tiwary Chandra Sekhar , Ajayan Pulickel M.
Published: April 2018

The realization of quasicrystals has attracted a considerable attention due to their unusual structures and properties. The concept of quasicrystals in the atomically thin materials is even more appealing due to the in‐plane covalent bonds and weak interlayer interactions. Here, it is demonstrated that 2D quasicrystals can be created/isolated from bulk phases because of long‐range interlayer ordered aperiodic arrangements. An ultrasonication‐assisted exfoliation of polygrained icosahedral Al–Pd–Mn quasicrystals at room temperature shows the formation of a large area of mono‐ and few layers in threefold quasicrystalline plane. The formation of these layers from random grain orientation consistently indicates that the threefold plane is most stable in comparison to the twofold and fivefold planes in icosahedral clusters. The above experimental observations are further supported with help of theoretical simulations. The mono‐ and few‐layered aperiodic planes render plentiful active sites for the catalysis of hydrogen evolution reaction. The threefold 2D quasicrystalline plane exhibits a hydrogen evolution reaction overpotential of ≈100 mV (160 times less than bulk counterpart) and long‐term durability. These systems constitute the first demonstration of quasicrystalline monolayer ordering in a free‐standing thin layer without requiring the support of periodic or aperiodic substrate.
Azo Compounds Derived from Electrochemical Reduction of Nitro Compounds for High Performance Li‐Ion Batteries
Authors: Luo Chao , Ji Xiao , Hou Singyuk , Eidson Nico , Fan Xiulin , Liang Yujia , Deng Tao , Jiang Jianjun , Wang Chunsheng
Published: April 2018

Organic compounds are desirable alternatives for sustainable lithium‐ion battery electrodes. However, the electrochemical properties of state‐of‐the‐art organic electrodes are still worse than commercial inorganic counterparts. Here, a new chemistry is reported based on the electrochemical conversion of nitro compounds to azo compounds for high performance lithium‐ion batteries. 4‐Nitrobenzoic acid lithium salt (NBALS) is selected as a model nitro compound to systemically investigate the structure, lithiation/delithiation mechanism, and electrochemical performance of nitro compounds. NBALS delivers an initial capacity of 153 mAh g−1 at 0.5 C and retains a capacity of 131 mAh g−1 after 100 cycles. Detailed characterizations demonstrate that during initial electrochemical lithiation, the nitro group in crystalline NBALS is irreversibly reduced into an amorphous azo compound. Subsequently, the azo compound is reversibly lithiated/delithiated in the following charge/discharge cycles with high electrochemical performance. The lithiation/delithiation mechanism of azo compounds is also validated by directly using azo compounds as electrode materials, which exhibit similar electrochemical performance to nitro compounds, while having a much higher initial Coulombic efficiency. Therefore, this work proves that nitro compounds can be electrochemically converted to azo compounds for high performance lithium‐ion batteries.
Low‐Saturation‐Intensity, High‐Photostability, and High‐Resolution STED Nanoscopy Assisted by CsPbBr3 Quantum Dots
Authors: Ye Shuai , Yan Wei , Zhao Mengjie , Peng Xiao , Song Jun , Qu Junle
Published: April 2018

Stimulated emission depletion (STED) nanoscopy is one of the most promising super‐resolution imaging techniques for microstructure imaging. Commercial CdSe@ZnS quantum dots are used as STED probes and ≈50 nm lateral resolution is obtained. Compared with other quantum dots, perovskite CsPbBr3 nanoparticles (NPs) possess higher photoluminescence quantum yield and larger absorption cross‐section, making them a more effective probe for STED nanoscopy. In this study, CsPbBr3 NPs are used as probes for STED nanoscopy imaging. The fluorescence intensity of the CsPbBr3 sample is hardly weakened at all after 200 min irradiation with a 39.8 mW depletion laser, indicating excellent photobleaching resistance of the CsPbBr3 NPs. The saturation intensity of the CsPbBr3 NPs is extremely low and estimated to be only 0.4 mW (0.126 MW cm−2). Finally, an ultrahigh lateral resolution of 20.6 nm is obtained for a single nanoparticle under 27.5 mW STED laser irradiation in CsPbBr3‐based STED nanoscopy imaging, which is a tenfold improvement compared with confocal microscopy. Because of its high fluorescence stability and ultrahigh resolution under lower depletion power, CsPbBr3‐assisted STED nanoscopy has great potential to investigate microstructures that require super‐resolution and long‐term imaging.
Intravenous thrombolysis in unwitnessed stroke onset: MR WITNESS trial results
Authors: Schwamm Lee H. , Wu Ona , Song Shlee S. , Latour Lawrence L. , Ford Andria L. , Hsia Amie W. , Muzikansky Alona , Betensky Rebecca A. , Yoo Albert J. , Lev Michael H. , Boulouis Gregoire , Lauer Arne , Cougo Pedro , Copen William A. , Harris Gordon J. , Warach Steven ,   on behalf of the MR WITNESS Investigators
Published: April 2018

Objective

Most acute ischemic stroke (AIS) patients with unwitnessed symptom onset are ineligible for intravenous thrombolysis due to timing alone. Lesion evolution on fluid‐attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI) correlates with stroke duration, and quantitative mismatch of diffusion‐weighted MRI with FLAIR (qDFM) might indicate stroke duration within guideline‐recommended thrombolysis. We tested whether intravenous thrombolysis ≤4.5 hours from the time of symptom discovery is safe in patients with qDFM in an open‐label, phase 2a, prospective study (NCT01282242).

Methods

Patients aged 18 to 85 years with AIS of unwitnessed onset at 4.5 to 24 hours since they were last known to be well, treatable within 4.5 hours of symptom discovery with intravenous alteplase (0.9mg/kg), and presenting with qDFM were screened across 14 hospitals. The primary outcome was the risk of symptomatic intracranial hemorrhage (sICH) with preplanned stopping rules. Secondary outcomes included symptomatic brain edema risk, and functional outcomes of 90‐day modified Rankin Scale (mRS).

Results

Eighty subjects were enrolled between January 31, 2011 and October 4, 2015 and treated with alteplase at median 11.2 hours (IQR = 9.5–13.3) from when they were last known to be well. There was 1 sICH (1.3%) and 3 cases of symptomatic edema (3.8%). At 90 days, 39% of subjects achieved mRS = 0–1, as did 48% of subjects who had vessel imaging and were without large vessel occlusions.

Interpretation

Intravenous thrombolysis within 4.5 hours of symptom discovery in patients with unwitnessed stroke selected by qDFM, who are beyond the recommended time windows, is safe. A randomized trial testing efficacy using qDFM appears feasible and is warranted in patients without large vessel occlusions. Ann Neurol 2018;83:980–993
Stabilized Vanadium Catalyst for Olefin Polymerization by Site Isolation in a Metal–Organic Framework
Authors: Comito Robert J. , Wu Zhenwei , Zhang Guanghui , Lawrence John A. , Korzyński Maciej D. , Kehl Jeffrey A. , Miller Jeffrey T. , Dincă Mircea
Published: April 2018

Vanadium catalysts offer unique selectivity in olefin polymerization, yet are underutilized industrially owing to their poor stability and productivity. Reported here is the immobilization of vanadium by cation exchange in MFU‐4l, thus providing a metal–organic framework (MOF) with vanadium in a molecule‐like coordination environment. This material forms a single‐site heterogeneous catalyst with methylaluminoxane and provides polyethylene with low polydispersity (PDI≈3) and the highest activity (up to 148 000 h−1) reported for a MOF‐based polymerization catalyst. Furthermore, polyethylene is obtained as a free‐flowing powder as desired industrially. Finally, the catalyst shows good structural integrity and retains polymerization activity for over 24 hours, both promising attributes for the commercialization of vanadium‐based polyolefins.
Establishment and characterization of a primary murine adipose tissue‐chip
Authors: Tanataweethum Nida , Zelaya Adelyn , Yang Feipeng , Cohen Ronald N. , Brey Eric M. , Bhushan Abhinav
Published: April 2018

Better experimental models are needed to enhance our understanding of metabolic regulation which is seen in obesity and metabolic disorders, such as type 2 diabetes. In vitro models based on microfluidics enable physiological representations of tissues with several advantages over conventional culture systems, such as perfused flow to better mimic the physiological environment. Although cell lines such as 3T3‐L1 have been incorporated in microfluidic devices, murine primary preadipocytes have not been differentiated and maintained for long‐term monitoring in these culture systems. We describe the differentiation of these cells into white adipose depots on a perfused microfluidic chip. We compare the effects of shear flow on these cells, and show with a direct comparison of high/low shear conditions that direct shear is detrimental to the viability of preadipocytes. We further develop a dual‐chamber microfluidic chip that enables perfusion while at the same time protects the cells from direct fluidic shear. We show that the dual‐layer microfluidic device enables long‐term culture of cells and allows stimulation of cells through perfusion—we can culture, differentiate, and maintain the differentiated adipose tissue for over multiple weeks in the device. Both triglycerides and lipolytic glycerol production increased significantly by several folds during differentiation. After successful differentiation, the adipocytes had upregulated expression of leptin and adiponectin, which are important makers of the final stage of adipogenic differentiation. In conclusion, the dual‐layer microfluidic device incorporated with primary adipocytes improves the understanding of adipose differentiation under dynamic conditions and is positioned to serve as a disease model for studying obesity and other metabolic disorders.
Modification, Biological Evaluation and SAR Studies of Novel 1H‐Pyrazol Derivatives Containing N,N′‐Disubstituted Urea Moiety as Potential Anti‐melanoma Agents
Authors: Ruan Ban‐Feng , Lin Meng‐Xue , Shao Qin , Wang Tian‐Hong , Zhang Qing , Dong Yu‐Lu , Bu Chao‐Nan , Xu Hua‐Jian , Zhou Ben‐Guo , Li Qing‐Shan
Published: April 2018

Malignant melanomas are amongst the most aggressive cancers. BRAF Inhibitors have exhibited therapeutic effects against BRAF‐mutant melanoma. In continuation of our earlier studies on anti‐melanoma agents based on 1H‐pyrazole skeleton, two sets of novel compounds that include 1H‐pyrazole‐4‐amines FA1 – FA13 and corresponding urea derivatives FN1 – FN13 have been synthesized and evaluated for their BRAFV600E inhibitory and antiproliferation activities. Compound FN10 displayed the most potent biological activity against BRAFV600E (IC50 = 0.066 μm) and the A375 human melanoma cell line (GI50 = 0.81 μm), which was comparable to the positive control vemurafenib, and more potent than our previously reported 1H‐pyrazole‐3‐amines and their urea derivatives. The results of SAR studies and molecular docking can guide further optimization and may help to improve potency of these pyrazole‐based anti‐melanoma agents.
Sulfur Microspheres Encapsulated in Porous Silver‐Based Shell with Superior Performance for Lithium‐Sulfur Batteries
Authors: Mo Yu‐Xue , Jiang You‐Hong , Lin Jin‐Xia , Zhou Yao , Li Jun‐Tao , Wu Qi‐Hui , Huang Ling , Liao Hong‐Gang , Sun Shi‐Gang
Published: April 2018

The lithium‐sulfur system is considered as one of the next‐generation batteries owing to its low‐cost and high theoretical energy density. However, the poor conductivity of sulfur, undesirable dissolution, and shuttling of lithium polysulfides are still main challenges for a practical application. Herein, a chemical plating method was developed to encapsulate sulfur microspheres within a porous Ag‐based thin shell of ca. 67 nm in thickness (denoted as S@Ag microcomposites). The sulfur content in the S@Ag particles is 89 wt%. With such structural and compositional merits, the core‐shell composites can effectively facilitate the electron transfer and alleviate the polysulfide dissolution. When utilized as cathode in Li−S batteries, the S@Ag microcomposites exhibit good electrochemical performance, featured by an initial charge capacity of 1231 mAh g−1 and a capacity of 922 mAh g−1 after 100 cycles at 0.2 C. The electrochemical performance of commercial S particles was also improved after treated by this chemical plating method. This study provides a simple and novel approach to fabricate S composite cathodes with high S content and promising electrochemical properties.
N4‐Tetradentate Chelators Efficiently Regulate Copper Homeostasis and Prevent ROS Production Induced by Copper‐Amyloid‐β1–16
Authors: Zhang Weixin , Liu Yan , Hureau Christelle , Robert Anne , Meunier Bernard
Published: April 2018

The disruption of copper homeostasis and the oxidative stress induced by Cu‐amyloids are crucial features of Alzheimer's disease pathology. The copper specific N4‐tetradendate ligands TDMQ20 and 1 are able to fully inhibit in vitro the aerobic oxidation of ascorbate induced by Cu‐Aβ1‐16, even in the presence of 100 molar equivalents of ZnII with respect to CuII, whereas other ligands with N2O2 or N3O2 coordination spheres failed to do so. This essential result indicates that, in addition to metal selectivity, the coordination sphere of copper chelators should exhibit a N4‐tetradendate motif to be able to reduce an oxidative stress in the zinc‐rich physiological environment of brain. The N4‐scaffolds of these two aminoquinoline‐based ligands, TDMQ20 or 1, suitable for a square‐planar coordination of copper(II), allowed them to enhance both the selectivity for copper and the ability to reduce the oxidative stress induced by copper‐amyloid in a zinc‐rich environment.
Synthesis of O6‐Corona[3]arene[3]pyridazines and Their Molecular Recognition Property in Organic and Aqueous Media
Authors: Lu Yao , Liang Dong‐Dong , Fu Zhan‐Da , Guo Qing‐Hui , Wang Mei‐Xiang
Published: April 2018

O6‐Corona[3]arene[3]pyridazines were synthesized from the one‐pot macrocyclic condensation reaction of 3,6‐dichlorotetrazine with 1,4‐dihydroquinone derivatives followed by the inverse electron demand Diels‐Alder reaction of the tetrazine rings with a cyclopentanone‐derived enamine. Conversion of six ester groups within macrocycle into all sodium acetate moieties afforded a water soluble O6‐corona[3]arene[3]pyridazine. The coronary macrocycle host formed complexes selectively with organic ammoniums and dinitrile guests in a 1: 1 stoichiometric ratio in organic solvents with association constants ranging from (2.96 ± 0.10) × 101 to (2.53 ± 0.33) × 105 L·mol−1. Water soluble O6‐corona[3]arene[3]pyridazine was also able to complex strongly with organic ammoniums in water to give an association constant up to (2.67 ± 0.21) × 104 L·mol−1. The pseudo‐rotaxane and inclusion structures of the host‐guest complexes were revealed by the X‐ray crystallography.
Improving semantic similarity retrieval with word embeddings
Authors: Yan Fengqi , Fan Qiaoqing , Lu Mingming
Published: April 2018

Word similarity matchmaking is one of the core research areas of information retrieval. The existing methods based on a synonym dictionary would lead to the problem of semantic gap, which could be caused by the absence of synonyms. To address this problem, we improve semantic similarity retrieval by incorporating word embeddings. Especially, word embeddings are trained by Word2Vec and then use them to depict the semantic similarity between words. Experiments are conducted on two different datasets, ie, one is a public long text dataset (ie, Reuters‐21578), and the other is a short text dataset (ie, 120ask) collected from a healthcare community. The experimental results on the two datasets show that the proposed method further improves the accuracy of the similarity retrieval.
Role of Hydrogen‐Bond Interactions in CO2 Capture by Wet Phosphonium Formate Ionic Liquid: A Raman Spectroscopic Study
Authors: Yasaka Yoshiro , Saito Yuma , Kimura Yoshifumi
Published: April 2018

The mechanism of CO2 absorption by a formate ionic liquid, [P4444]HCOO, was studied by Raman spectroscopy. The band area for the symmetric CO2 stretching of the formate anion linearly decreases with the CO2 loading. From the slope of the decrease, 1 : 1 stoichiometry is proven between CO2 and the formate anion. The result favors the mechanism we proposed in a preceding work [J. Chem. Eng. Data 61, 837 (2016)]: HCOO−+CO2+H2O→HCOOH+HCO3−→[HCOOH…HCO3−]. Further support for the mechanism is obtained by the observation of antisymmetric vibration of CO for the proposed hydrogen‐bonded complex between HCOOH and HCO3−. The bands appeared as a doublet (1677 and 1730 cm−1) as this complex has two carbonyl groups. Based on DFT calculations, the [HCOOH…HCO3−] complex is supposed to be the most abundant form of chemisorbed CO2.
One‐Dimensional ABX3‐Type Fluorescent Crystal: CH3NH3ZnI3
Authors: Wei Hao , Zhang Liuqi , Wang Jilin , Chen Jian , Zheng Guoyuan , Long Fei , Zou Zhengguang , Gao Yihua
Published: April 2018

The ABX3‐type organic‐inorganic hybrid compound CH3NH3ZnI3 is grown by a liquid diffusion method in methylbenzene solution for the first time. The as prepared samples are characterized by single crystal diffraction, XRD, Infrared (IR) and Raman spectra, TG, UV‐Vis and PL respectively. The results indicate that CH3NH3ZnI3 crystal is demonstrated a monoclinic system with the space group P21/n at room temperature. And the sample presents relatively good thermal stability until 270 °C and wide band gap of about 3.88 eV. Besides, when the crystal is excited at 330 nm in the PL characterization, it could exhibit a green fluorescence emission band a maximum value at 521 nm. Therefore, this kind of ABX3‐type organic‐inorganic hybrid compound will be a promising candidate for optical and electronic applications.
Neutral Red and Ferroin as Reversible and Rapid Redox Materials for Redox Flow Batteries
Authors: Hong Jeehoon , Kim Ketack
Published: April 2018

Neutral red and ferroin are used as redox indicators (RINs) in potentiometric titrations. The rapid response and reversibility that are prerequisites for RINs are also desirable properties for the active materials in redox flow batteries (RFBs). This study describes the electrochemical properties of ferroin and neutral red as a redox pair. The rapid reaction rates of the RINs allow a cell to run at a rate of 4 C with 89 % capacity retention after the 100th cycle. The diffusion coefficients, electrode reaction rates, and solubilities of the RINs were determined. The electron‐transfer rate constants of ferroin and neutral red are 0.11 and 0.027 cm s−1, respectively, which are greater than those of the components of all‐vanadium and Zn/Br2 cells.
Trellis code‐aided high‐rate M‐QAM space‐time labeling diversity using a unitary expansion
Authors: Dlodlo Buthanani , Xu Hongjun
Published: April 2018

In this paper, we present a high‐rate M‐ary quadrature amplitude modulation (M‐QAM) space‐time labeling diversity (STLD) system that retains the robust error performance of the conventional STLD system. The high‐rate STLD is realised by expanding the conventional STLD via a unitary matrix transformation. Robust error performance of the high‐rate STLD is achieved by incorporating trellis coding into the mapping of additional bits to high‐rate codes. The comparison of spectral efficiency between the proposed trellis code‐aided high‐rate STLD (TC‐STLD) and the conventional STLD shows that TC‐STLD with 16‐QAM and 64‐QAM respectively achieves a 12.5% and 8.3% increase in spectral efficiency for each additional bit sent with the transmitted high‐rate codeword. Moreover, we derive an analytical bound to predict the average bit error probability performance of TC‐STLD over Rayleigh frequency‐flat fading channels. The analytical results are verified by Monte Carlo simulation results, which show that the derived analytical bounds closely predict the average bit error probability performance at high signal‐to‐noise ratios (SNR). Simulation results also show that TC‐STLD with 1 additional bit achieves an insignificant SNR gain of approximately 0.05 dB over the conventional STLD, while TC‐STLD with 2 additional bits achieves an SNR gain of approximately 0.12 dB.
Habitat assessment of Marco Polo sheep (Ovis ammon polii) in Eastern Tajikistan: Modeling the effects of climate change
Authors: Salas Eric Ariel L. , Valdez Raul , Michel Stefan , Boykin Kenneth G.
Published: April 2018

Identifying the factors predicting the high‐elevation suitable habitats of Central Asian argali wild sheep and how these suitable habitats are affected by the changing climate regimes could help address conservation and management efforts and identify future critical habitat for the species in eastern Tajikistan. This study used environmental niche models (ENMs) to map and compare potential present and future distributions of suitable environmental conditions for Marco Polo argali. Argali occurrence points were collected during field surveys conducted from 2009 to 2016. Our models showed that terrain ruggedness and annual mean temperature had strong correlations on argali distribution. We then used two greenhouse gas concentration trajectories (RCP 4.5 and RCP 8.5) for two future time periods (2050 and 2070) to model the impacts of climate change on Marco Polo argali habitat. Results indicated a decline of suitable habitat with majority of losses observed at lower elevations (3,300–4,300 m). Models that considered all variables (climatic and nonclimatic) predicted losses of present suitable areas of 60.6% (6,928 km2) and 63.2% (7,219 km2) by 2050 and 2070, respectively. Results also showed averaged habitat gains of 46.2% (6,106 km2) at much higher elevations (4,500–6,900 m) and that elevational shifts of habitat use could occur in the future. Our results could provide information for conservation planning for this near threatened species in the region.
Strong associations between plant genotypes and bacterial communities in a natural salt marsh
Authors: Zogg Gregory P. , Travis Steven E. , Brazeau Daniel A.
Published: April 2018

Although microbial communities have been shown to vary among plant genotypes in a number of experiments in terrestrial ecosystems, relatively little is known about this relationship under natural conditions and outside of select model systems. We reasoned that a salt marsh ecosystem, which is characterized by twice‐daily flooding by tides, would serve as a particularly conservative test of the strength of plant–microbial associations, given the high degree of abiotic regulation of microbial community assembly resulting from alternating periods of inundation and exposure. Within a salt marsh in the northeastern United States, we characterized genotypes of the foundational plant Spartina alterniflora using microsatellite markers, and bacterial metagenomes within marsh soil based on pyrosequencing. We found significant differences in bacterial community composition and diversity between bulk and rhizosphere soil, and that the structure of rhizosphere communities varied depending on the growth form of, and genetic variation within, the foundational plant S. alterniflora. Our results indicate that there are strong plant–microbial associations within a natural salt marsh, thereby contributing to a growing body of evidence for a relationship between plant genotypes and microbial communities from terrestrial ecosystems and suggest that principles of community genetics apply to this wetland type.
FEM simulation of local field enhancement close to lamination interface of permittivity‐graded material
Authors: Kurimoto Muneaki , Ozaki Hiroya , Sawada Tooru , Funabashi Toshihisa , Kato Takeyoshi , Suzuoki Yasuo
Published: April 2018

For size reduction of gas insulated switchgears (GIS), application of permittivity‐graded material to insulating spacer has been studied. The electric‐field‐enhancement close to the lamination interface of the permittivity‐graded material obtained by laminating epoxy composites with different permittivities was investigated. The FEM simulation revealed that the increase of the layer number of the permittivity‐graded material could reduce the field enhancement close by the lamination interface, even when considering electric field distortion near the individual high‐permittivity particles filled in each layer.
Seascape connectivity and the influence of predation risk on the movement of fishes inhabiting a back‐reef ecosystem
Authors: Rooker Jay R. , Dance Michael A. , Wells R. J. David , Quigg Antonietta , Hill Ronald L. , Appeldoorn Richard S. , Padovani Ferreira Beatrice , Boswell Kevin M. , Sanchez Phillip J. , Moulton David L. , Kitchens Larissa L. , Rooker Garrett J. , Aschenbrenner Alexandre
Published: April 2018

The mangrove–seagrass–patch reef (MSP) ecosystem serves as the principal back‐reef nursery for many reef fishes in the Caribbean, but the functional roles of habitats that form this seascape remain unclear. We assessed ecosystem and trophic connectivity of two common reef fishes (schoolmaster, Lutjanus apodus; white grunt, Haemulon plumierii) and one predator (great barracuda, Sphyraena barracuda) in a Caribbean MSP ecosystem using acoustic telemetry and natural dietary tracers. Triangulated positions from an acoustic positioning system indicated that L. apodus and H. plumierii relied on multiple habitats within this MSP ecosystem, occupying areas with more cover (lower risk) during the day and areas with less cover (higher risk) at night. During the day, both species exhibited limited movement away from structured habitats (e.g., mangroves, patch reef) and avoided the primary activity space of S. barracuda in the central channel over sand bottom or seagrass. At night, L. apodus moved into the channel and adjacent seagrass beds on the margin of this high‐risk area when S. barracuda occurrence was reduced, suggesting that this species adjusts its foraging activities to minimize encounter rates with predators. Haemulon plumierii also displayed distinct day–night shifts with directed movements at twilight across higher risk habitat to nighttime locations in seagrass. Conspicuous changes in the rate of movement were also detected at different times of the day, and observed mismatches between movement rates of S. barracuda and our two potential prey species appeared to be a behavioral response to reduce their vulnerability. Dietary tracer analysis supported the premise that observed shifts to nocturnal habitats were associated with foraging, with significant contributions of organic matter derived from nighttime locations. Findings from this study clearly demonstrate that the configuration of habitats and spatiotemporal variability in predation risk are key determinants of movement and foraging activities for these species, indicating that an improved understanding of seascape connectivity is critical to the management of reef‐dependent species.
Renaissance of the Stella Quadrangula: The Lanthanoid Nitride Tellurides Ln13N5Te12 (Ln = La–Nd)
Authors: Lissner Falk , Foltin Markus L. , Schleid Thomas
Published: April 2018

Ln13N5Te12 (Ln = La–Nd), a quite unusual composition of the lanthanoid(III) nitride tellurides, appears with a new crystal structure and can be obtained by reactions of lanthanoid metal (Ln) with elemental tellurium (Te), sodium azide (NaN3), elemental iodine (I2) and sodium iodide (NaI) as flux in evacuated fused silica tubes for seven days at 900 °C. The black, shard‐shaped single crystals of the short new series Ln13N5Te12 (Ln = La–Nd) crystallize monoclinically in the space group P21/m with lattice parameters ranging from a = 1039.86(7), b = 1373.29(9), c = 1311.78(9) pm, β = 100.103(3)° for La13N5Te12 to a = 1016.73(7), b = 1337.58(9), c = 1288.92(9) pm, β = 100.094(3)° for Nd13N5Te12 and Z = 2. Unlike the other ternary compounds of the lanthanoid(III) nitride tellurides, two different types of isolated oligomers containing edge‐sharing [NLn4]9+ tetrahedra occur in their crystal structure. The fusion of two [NLn4]9+ units via one common edge forms [N2Ln6]12+ bitetrahedra, which are already known from the Ln3NTe3 examples with Ln = Gd–Ho. In contrast, the [N3Ln7]12+ trimers built up by three [NLn4]9+ tetrahedra with two sharing edges for each [NLn4]9+ unit, but three common edges overall, represent a new highlight. Both kinds of oligomers can be traced back to a stella quadrangula [N4Ln8]12+ and are embedded in a dense matrix of Te2– anions according to {[Ln6N2][Ln7N3]Te12}.
Diastereoselective Synthesis and Catalytic Activity of Two Chiral cis‐Dioxidomolybdenum(VI) Complexes
Authors: Haghdoost Mohammad Mehdi , Zwettler Niklas , Golbaghi Golara , Belaj Ferdinand , Bagherzadeh Mojtaba , Schachner Jörg A. , Mösch‐Zanetti Nadia C.
Published: April 2018

Two enantiomerically pure chiral dioxidomolybdenum(VI) complexes (1 and 2) of the type [MoO2L] (L = dianionic, tetradentate ONNO‐ligand) were synthesized and investigated in enantioselective oxidation reactions. The solid‐state structures of complex 1 and 2, determined via single‐crystal X‐ray diffraction analysis revealed two fundamentally different coordination geometries: a C1‐symmetric cis‐β isomer (Λ‐1), and a C2‐symmetric cis‐α isomer (Δ‐2). In both cases, only one of the two possible helical enantiomers (Λ‐ or Δ‐helix) was formed. The complexes were examined as precatalysts in the epoxidation of the challenging prochiral substrate trans‐stilbene, using either tert‐butyl hydroperoxide (TBHP) or cumyl hydroperoxide (CHP) as oxidants. The asymmetric cis‐β complex 1 was found to be significantly more active in the epoxidation than its cis‐α counterpart 2, asymmetric induction was, however, negligible for both complexes. The complexes were also tested in catalytic enantioselective sulfoxidation reactions where chiral induction could be achieved, albeit small. The observed putative molybdenum oxido‐peroxido intermediate 1‐O2 could be identified as an important precomplex before formation of the active catalyst in sulfoxidation.
Oxidative Cleavage of Methyl 9,10‐Epoxystearate over WO3/MCM‐41 for Methyl 9‐Oxononanoate Production
Authors: Lu Meizhen , Peng Libo , Xie Qinglong , Nie Yong , Liu Xuejun , Lu Xianghong , Ji Jianbing
Published: April 2018

At present, the utilization of grease has attracted more and more attention. This article presents a simple method that efficiently cleaves methyl oleate‐derived methyl 9,10‐epoxystearate (a) to give high yields of methyl 9‐oxononanoate (d) with nonanal (c) as co‐product. A WO3/MCM‐41 catalyst is prepared via direct mixed‐gel synthesis. The catalyst is tested in the oxidative cleavage of a to produce d which can be used as a polymer precursor or an important feedstock. The effects of WO3 loading, temperature, time, H2O2/a molar ratio, catalyst/a weight ratio, and t‐BuOH/a weight ratio on the a conversion and d yield are examined using single‐factor experiments. The optimal reaction conditions are determined by orthogonal experiments. The optimal WO3 loading, temperature, time, H2O2/a molar ratio, catalyst/a weight ratio, and t‐BuOH/a weight ratio are 35%, 80 °C, 20 min, 1.3, 0.04, and 0.5, respectively. Under these conditions, the a conversion and d yield reach 99.4 and 78.4%, respectively. In addition, the catalyst shows no significant decrease in activity after being reused three times. Moreover, the reaction mechanism is studied based on the product distribution over time.

Practical Applications: Few studies on methyl 9,10‐epoxystearate used as the raw material to give methyl 9‐oxononanoate and nonanal are found. Because the ethylene oxide bond is more unstable than the carbon–carbon double bond, the oxidative cleavage of methyl 9,10‐epoxystearate is easier than cleavage of methyl oleate that allows the oxidative cleavage to be done under milder conditions. Methyl 9‐oxononanoate can be converted to a monomer of high‐value polymers and is also an important feedstock in the production of chemicals. The co‐product nonanal is a natural spice which can be used in the fragrance industry. The results show that the reaction time is short and methyl 9‐oxononanoate yield is high under mild reaction conditions. The method in this study can also be widely used in other oxidative cleavage reactions of epoxides.

Methyl 9,10‐epoxystearate is used as the raw material to produce methyl 9‐oxononanoate with nonanal as co‐product using WO3/MCM‐41 as catalyst and H2O2 as oxidant.
First Total Synthesis of Original Chalcone–Flavone Dimers as Cissampeloflavone Analogues
Authors: Thévenin Marion , Thoret Sylviane , Dubois Joëlle
Published: April 2018

The total synthesis of furoflavones closely related to the natural product cissampeloflavone was explored following different pathways. The involvement of a flavone as a key intermediate proved to be the most efficient way to form the 7‐phenyl‐5H‐furo[3,2‐g]chromen‐5‐one scaffold, and the first example of furoflavone formation was achieved in this way. For the synthesis of chalcone–flavone dimers, two different strategies were examined: either acylation at the very end of the synthesis, or introduction of the 3‐acyl group during furan‐ring formation. The final acylation was hardly achievable with hindered benzoyl chlorides, but a simpler 4‐methoxybenzoyl group was added to the furoflavone in modest yield. The alternative direct introduction of this acyl group during furan formation proved to be more efficient. Conjugate addition of an iodoflavone to an ynone followed by intramolecular Heck cyclization gave the best results, leading to the first synthetic chalcone–flavone dimer ever described.
Contiguous Quaternary Centers from a AuI‐Catalyzed Nazarov Cyclization
Authors: Congmon Jonathan , Tius Marcus A.
Published: April 2018

The cationic AuI‐catalyzed cyclization of highly substituted enynes has been shown to provide cyclopentenones with up to two contiguous, all‐carbon atom quaternary centers in a diastereospecific process. In the more challenging examples in which two contiguous quaternary centers are formed during cyclization, the essential role of a ethoxycarbonyl group to control the reaction outcome has been demonstrated. The less challenging examples that lead to a single quaternary center in the ring require no activation by aryl or by electron withdrawing groups.
High Temperature Polymer Electrolyte Membrane Fuel Cells – On the Way to Commercial Maturity
Authors: Liu Xiaoteng (Terence) , Friedl Jochen
Published: April 2018

No abstract.