bluuebunny/crossref_metadata_2025 huggingface dataset:
The Acquisition of French (L3) Coda Consonant Clusters by English (L2) Learners Speakers of Persian (L1): An Optimality Account
Authors: Dadbakhsh Fatemeh , Jabbari Ali Akbar
Published: December 2016

The present study presents an Optimality Theoretic account of syllable codas in French by the learners whose first and second languages are Persian and English respectively. Additionally, it investigates transfer at the L3 initial state, testing between the three hypotheses of Full Transfer/ Full Access (Schwartz & Sprouse, as cited in Özçelik, 2009) i.e., the main L1 transfer effect, L2 Status Factor (Bardel & Falk, 2007, 2011) i.e., the main L2 transfer effect, and Cumulative Enhancement Model (Flynn et al., 2004) i.e., all previously known languages’ positive or neutral transfer effect. As a matter of fact, OT is also used to see whether it supports what is obtained through transfer effects or not. To do so, two groups of Persian native speakers, but with differing English proficiencies (lower-intermediate and upper-intermediate) that were at the initial state of acquiring L3 French were asked to complete two tests, namely oral judgment test and production test. The analysis of the data was done through the mixed between-within subjects ANOVA. Results of the transfer effect provided a major role for the “L2 status factor”, while casting doubt on the tenability of several aspects of the CEM and provided no support for the FT/FA hypothesis. Regarding OT, the following constraint hierarchies were obtained for OJT and PT respectively: MAX-IO>> DEP-IO>>COMPLEX>> INDENT-IO and DEP-IO>> MAX-IO>> INDENT-IO>> COMPLEX. In fact, these rankings, especially the latter one, advocated the L2 constraint hierarchy and this was in accordance with the results of cross-linguistic effect, providing a major role for the L2 status factor.
Theoretical Foundations of Translation Studies
Authors: Zendehboudi Mehran , Farsian Mohammad Reza
Published: December 2016

Epistemologies of translation are a complicated subject that is beyond the scope of this article. As such, only the critical points have been addressed in this paper. One key epistemological issue is the analysis of discourse in any science. In this article, four scenarios of translation studies have been discussed. An underlying concept in translation studies is the issue of fidelity in translation. In this paper, the trajectory of this concept is analyzed in brief. It is followed by a reflection on two fundamental concepts of source oriented (Sources) and target oriented translation approaches, as they occupy a particular position in the translation. The last section of the article investigates dichotomies in the field of translation studies, including the theory of the action, the untranslatability versus translatability, art versus science, and etc. In this paper, we try to study theoretical principles of translatology. So we consider four important speeches of Jean Rene Ladmiral: Prescriptive translatology, Descriptive translatology, Productive translatology, scientific translatology and then we consider faithfulness in translation. Ladmiral suggests two concepts for fidelity in translation: The source oriented (sources) and target oriented. These two concepts are the fundamental concepts in translatology. In the next step the translation science is investigated in various languages such as English, German and at last in French. Finally, we take a look at binary concepts: Theory vs. action, Translatability vs. untranslatability, Art vs. Science. This paper is in epistemology scope of translation and does not have pedagogical aspect, in other words, it is a function-oriented translation.
Stress: An Impediment to Learning English
Authors: Mehrban Maryam , Pourghasemian Hossein
Published: December 2016

The present research aims to study the impacts of stress on learning English among English students in Saveh city. Using descriptive survey method and simple random sampling, the research was completed on a sample population of 60 among all the English learners in Saveh city. The learners have been homogenous in assistance with Preliminary English Test (PET), and then using the standard questionnaire of Ang vo Goran’s (2006), the students have been divided into two groups (with stress and without stress).The validity of instruments has been confirmed by the supervisor and the validity was calculated 0.76. An achievement test including 67 questions has been used as the research instrument. The comparative test, which was the most significant result of the research, suggested that stress is an obstacle to learning process.
Curriculum Typology
Authors: Marzooghi Rahmatallah
Published: December 2016

An abstract is a brief and comprehensive summary of the contents of the article. It allows readers to survey the various definitions that have been presented by scholars about the concept of curriculum as a “plan” or “product”, and due to the vast variation of definitions, many classifications have been made in regarding them. Since “the curriculum” is not a “type” but has “types” itself, it is not possible to present a comprehensive definition for all those curricula such as intended, implemented, learned, implicit, hidden, sterilized, omitted, neglected, empty, taught, not taught, existed, non-existed, and so on. Therefore each curriculum must be defined based on its own unique type. In this article by using a new and innovative approach, more than 200 types of curricula, based on their common traits, are classified into 16 categories. The analysis and classification which are unique and unexampled in its own nature in the curriculum literature explain some controversies about the definitions and types of curricula categorization.
The Status of Women in the Idea of “Rifa’a Tahtavy”
Authors: Vamkani Zahra Khosravi , Komleh Mehdi Najafi
Published: December 2016

Arab intellectuals in the nineteenth century during their travels to Western countries wanted to reform the social problems of their country, which mixed with religion and tradition. Some of these problems were Women’s issues, including education, dress, marriage, etc. The intellectuals included of diverse groups of people: poet, author, historian, etc. “Rifa’a Tahtavy 1801-1873 AD” was one of the scholars of the movement that believed in gender equality in the areas of personal and social. In his view of point, modeling from European countries in the field of education was critical. Rifa’a believed that there is a strong relationship between the progress of women and promotion of intellectual and cultural level. In his mind, achievement of nations depends on their respect for women. He knew mutual love as the primary condition for the marriage of girls and chastity and decency of women affiliated with the correct training. In this article, we will attempt to look at women’s issues, including education, employment, marriage, and dress in Tahtavy views.
An Exploration of the Relationship between Oral Language Proficiency and the Success of English Language Learners in Reading Recovery
Authors: Farazdast Hossein , Pishkar Kian
Published: December 2016

The diverse population of learners includes students who are high performing in reading as well as those who struggle with reading. This research concerns struggling readers. The goal of teachers is to identify struggling readers and discover ways to address the reading needs of those students. Pinnell (2006) stated that teachers have a common goal: to make literacy a true part of the lives of all students. There are many interventions to help struggling readers. Reading Recovery (RR) is a short-term reading intervention program designed to help the children develop effective strategies for reading and reach average levels for their particular peer group (Fountas & Pinnell, 1996). Research has confirmed the positive impact of RR on readers who struggle (Allington, 2005; Clay, 1993; McKee, 2006; Schwartz, 2005). In particular, Allington (2005) outlined five principles of scientific reading instruction: (a) classroom organization; (b) matching pupils to texts; (c) access to interesting texts, choice, and collaboration; (d) writing and reading; and (e) expert tutoring. Research has shown that RR addresses four of these five principles.
Semiotics in Haroun Hashem Rashid Lyrics Relying on the Theory of Pierce
Authors: Pashaki Ahmad Mohammadi Nejad , Shahri Ahmad Reza Hidarian , Seedighi Kolsom
Published: December 2016

Today semiotics mainly influenced by Pierce’s thoughts and demarches has become an independent discipline which is used as an interdisciplinary aspect of text analysis. This approach, which uses linguistics, sociology, literature, and so forth is an efficient method of analysis. Semiotic analysis of the works in Arabic literature could lay the groundwork for a new reading of them, leading to better understanding of the texts. While introducing literary semiotics, this paper thus examines the poetry of Haroun Hashem Rashid based on the approach in question. It also appears that the encryption is related to the creator, aesthetics, text interrelationship, time, place, and the form of a poem. Given the work of Haroun Hashem Rashid, a number of roles are presented that rebuild a powerful relationship within a turbulent life, which is fluctuating between the pleasant and unpleasant symptoms. This associates likely and widespread meanings with the pure human being concepts. The results show that there is a high reliance on hypertext elements and the events of the author’s life in his poetry in addition to the text elements. However, of all the most frequent indices of his poetry, time, characters, and the indications of locations can be noted.
Di-transitive Constructions in Persian Based on the Minimalist Program
Authors: Shahsavari Azam
Published: December 2016

This article studies the structure of double-object constructions, a challenging structure in Persian, based on Bowers’ (1993, 2001) minimalist approach. The major goal here is to evaluate the effectiveness of Bowers’ approach in analyzing such constructions. First, we reviewed the Persian grammarians’ analyses of transitivity and the continuity of the transitive system which claims that there are verbs with one object at one side of this continuum and verbs with two objects at the other side. Based on this analysis, transitivity differs from verb to verb. In other words, di-transitive verbs are more transitive than other verbs because they have to get two objects so that the omission of one of these objects makes the construction ungrammatical. In this study we used Bowers’ approach (1993, 2001), i.e., double predication phrase design, to analyze the above mentioned structures in Persian. Later the sequence of the direct-indirect object was identified to be the unmarked grammatical sequence in Persian based on native speakers’ language intuition.
The Effect of Visual and Auditory Input Enhancement on Vocabulary Acquisition of Iranian EFL University Students
Authors: Ghafouri Ali , Masoomi Mohsen
Published: December 2016

This study was an attempt to investigate the effect of input enhancement instruction on vocabulary acquisition among Iranian university students. Moreover, the possible effect of two kinds of input enhancement (i.e., auditory and visual) was examined. To this end, 75 Iranian university students, majoring English language Teaching at Applied Science and Technology of Kurdistan University, Iran, were randomly selected. The method used in this study was quantitative research and the true experimental design. One experimental group received vocabulary instruction via visual input enhancement, and the other experimental group was taught vocabulary via auditory input enhancement. After administering the posttest, the dada was analyzed by one-way ANOVA. The findings revealed that both auditory and visual input enhanced instruction had a significant effect on the vocabulary development of Iranian EFL students. In addition, comparing the efficacy of two types of instruction, the results indicated that the effect of either visual or auditory input enhancement for both experimental EFL university students were fairly the same in Iranian EFL educational setting.
Minimalism in Mawlana’s Masnavi
Authors: Bighashi Hossein , Alizadeh Shahin Ojagh
Published: December 2016

Minimalism means the writer uses minimum words and brevity to express a story in a simple plan. Although it is a new category in west, there are extensive examples in Iran comprehensive literature which are coincident with the features of minimal stories. Mawlana’s Masnavi Manavi is significant based on storytelling in addition to its content value, religious, moral and mystic teachings. Brevity, realism, the simplicity of the language, having an attractive theme are the most important features of minimalism that this study could achieve ten features through revising and comparing two first books which have conformity with minimalism process. This study attempts to investigate the matter of telling these fictions and tales in two first books of Masnavi along features of minimal story.
The Impact of Student-Based Instruction on Improving IBT TOEFL Scores of Iranian Students
Authors: Afsahi Seyed Ehsan , Biria Reza
Published: December 2016

Student-based instruction is a form of collaborative education that students play an active role in learning the process. Student’s activity is in group forms. The teacher is presenting in class just to answer students’ questions. The paradigm and pattern shifting away from teaching to an emphasis on learning have persuaded power to be changed and moved from the teacher to the student. Being a qualitative research paper, it is an attempt to investigate the impact of student-based instruction on improving IBT scores of Iranian students. The participants of this study will include two groups of male and female students each consisting of 15, all of whom are enrolling in TOEFL classes in Kish English Institute in Tehran. The participants will be assigned to control (N=15) and experimental (N=15) groups. The participants in the experimental and control groups exposed to the same content, but a different instructional method. The participants are 30 students in Advance level in one class, male and female, aged 25-35 years old. SPSS and Independent T-test are used to measure hypothesis of research and to analyze data, respectively. According to the results of this investigation, student-based instruction significantly affects IBT TOEFL scores of students.
Effect of Different Variables on the Size Distribution of Barium Chromate Nanoparticles
Authors: Simiari Mehdi , Manteghian Mehrdad , Ghashamshmi-Iraj. Malihe
Published: December 2016

In this study, the synthesis of BaCrO4 nanoparticles is performed by the reaction between Ba(NO3)2 and (NH4)2CrO4 in the presence of surfactant. Different analyses such as X-ray diffraction (XRD), Transmission electron microscopy (TEM), Dynamic light scattering (DLS), and Energy Dispersive X-ray analysis (EDAX) are carried out to identify the features of nanoparticles. The tests are conducted in different concentrations of reactants and surfactants, and at the end, the results are compared. Optimum concentration is also measured and reported to achieve smaller nanoparticles. The results indicate that, in the synthesis of BaCrO4 nanoparticles, the best performance belongs to Sodium Citrate.
Assembling the Tat protein translocase
Authors: Alcock Felicity , Stansfeld Phillip J , Basit Hajra , Habersetzer Johann , Baker Matthew AB , Palmer Tracy , Wallace Mark I , Berks Ben C
Published: December 2016

The twin-arginine protein translocation system (Tat) transports folded proteins across the bacterial cytoplasmic membrane and the thylakoid membranes of plant chloroplasts. The Tat transporter is assembled from multiple copies of the membrane proteins TatA, TatB, and TatC. We combine sequence co-evolution analysis, molecular simulations, and experimentation to define the interactions between the Tat proteins of Escherichia coli at molecular-level resolution. In the TatBC receptor complex the transmembrane helix of each TatB molecule is sandwiched between two TatC molecules, with one of the inter-subunit interfaces incorporating a functionally important cluster of interacting polar residues. Unexpectedly, we find that TatA also associates with TatC at the polar cluster site. Our data provide a structural model for assembly of the active Tat translocase in which substrate binding triggers replacement of TatB by TatA at the polar cluster site. Our work demonstrates the power of co-evolution analysis to predict protein interfaces in multi-subunit complexes.
Young adult born neurons enhance hippocampal dependent performance via influences on bilateral networks
Authors: Zhuo Jia-Min , Tseng Hua-an , Desai Mitul , Bucklin Mark E , Mohammed Ali I , Robinson Nick TM , Boyden Edward S , Rangel Lara M , Jasanoff Alan P , Gritton Howard J , Han Xue
Published: December 2016

Adult neurogenesis supports performance in many hippocampal dependent tasks. Considering the small number of adult-born neurons generated at any given time, it is surprising that this sparse population of cells can substantially influence behavior. Recent studies have demonstrated that heightened excitability and plasticity may be critical for the contribution of young adult-born cells for certain tasks. What is not well understood is how these unique biophysical and synaptic properties may translate to networks that support behavioral function. Here we employed a location discrimination task in mice while using optogenetics to transiently silence adult-born neurons at different ages. We discovered that adult-born neurons promote location discrimination during early stages of development but only if they undergo maturation during task acquisition. Silencing of young adult-born neurons also produced changes extending to the contralateral hippocampus, detectable by both electrophysiology and fMRI measurements, suggesting young neurons may modulate location discrimination through influences on bilateral hippocampal networks.
Structural evidence for Arabidopsis glutathione transferase AtGSTF2 functioning as a transporter of small organic ligands
Authors: Ahmad Laziana , Rylott Elizabeth L. , Bruce Neil C. , Edwards Robert , Grogan Gideon
Published: December 2016

Glutathione transferases (GSTs) are involved in many processes in plant biochemistry, with their best characterised role being the detoxification of xenobiotics through their conjugation with glutathione. GSTs have also been implicated in noncatalytic roles, including the binding and transport of small heterocyclic ligands such as indole hormones, phytoalexins and flavonoids. Although evidence for ligand binding and transport has been obtained using gene deletions and ligand binding studies on purified GSTs, there has been no structural evidence for the binding of relevant ligands in noncatalytic sites. Here we provide evidence of noncatalytic ligand‐binding sites in the phi class GST from the model plant Arabidopsis thaliana, AtGSTF2, revealed by X‐ray crystallography. Complexes of the AtGSTF2 dimer were obtained with indole‐3‐aldehyde, camalexin, the flavonoid quercetrin and its non‐rhamnosylated analogue quercetin, at resolutions of 2.00, 2.77, 2.25 and 2.38 Å respectively. Two symmetry‐equivalent‐binding sites (L1) were identified at the periphery of the dimer, and one more (L2) at the dimer interface. In the complexes, indole‐3‐aldehyde and quercetrin were found at both L1 and L2 sites, but camalexin was found only at the L1 sites and quercetin only at the L2 site. Ligand binding at each site appeared to be largely determined through hydrophobic interactions. The crystallographic studies support previous conclusions made on ligand binding in noncatalytic sites by AtGSTF2 based on isothermal calorimetry experiments (Dixon et al. (2011) Biochem J 438, 63–70) and suggest a mode of ligand binding in GSTs commensurate with a possible role in ligand transport.
The bidirectional associations between state anger and rumination and the role of trait mindfulness
Authors: Borders Ashley , Lu Shou‐En
Published: December 2016

Rumination is associated with exacerbated angry mood. Angry moods may also trigger rumination. However, research has not empirically tested the bidirectional associations of state rumination and anger, as experience sampling methodology can do. We predicted that state anger and rumination would be bi‐directionally associated, both concurrently and over time, even controlling for trait anger and rumination. In addition, because mindfulness is associated with rumination and anger at the bivariate level, we examined the effect of trait mindfulness on the bidirectional association between state rumination and anger. We examined two hypotheses: (i) state rumination mediates the effect of trait mindfulness on state anger; and (ii) trait mindfulness weakens, or moderates, the bidirectional associations between state rumination and anger. In an experience‐sampling study, 200 college students reported their current ruminative thinking and angry mood several times a day for 7 days. Mixed model analyses indicated that state anger and rumination predicted each other concurrently. In cross‐lagged analyses, previous anger did not uniquely predict current rumination; previous rumination predicted current anger, although the effect was small. In support of our hypothesis, state rumination mediated the association between trait mindfulness and state anger. Additionally, trait mindfulness moderated the concurrent and cross‐lagged associations between state rumination and anger, although the results were complex. This study contributes new information about the complex interplay of rumination and anger. Findings also add support to the theory that mindfulness decreases emotional reactivity. Aggr. Behav. 43:342–351, 2017. © 2016 Wiley Periodicals, Inc.
Temperature Control of Mussel‐Inspired Chemistry toward Hierarchical Superhydrophobic Surfaces for Oil/Water Separation
Authors: Wang Yanbing , Shang Bin , Hu Xiaoxi , Peng Bo , Deng Ziwei
Published: December 2016

By adopting polydopamine chemistry, a single‐step approach is introduced toward hierarchical surfaces with tunable surface wetting properties via adjusting the reaction temperature. After the hydrophobic surface decoration, the tunable superhydrophobicity of the surfaces is achieved. This tunability has been realized on a series of materials with different surface geometries, including silica nanospheres and microrods, silicon wafer, stainless steel mesh, and melamine‐formaldehyde sponge. These superhydrophobic mesh and sponge are ideal candidates for collecting various oils/organic solvents from water, because not only they exhibit high absorption/separation capacity, excellent selectivity, and extraordinary recyclability, but also they are highly chemically resistant, environmentally stable and mechanically durable. This whole procedure is straightforward, cost‐effective, green, and material‐ and surface geometry‐independent, more importantly, the obtained surface morphology is tunable, providing more opportunities to cater the demands from fundamental and practical fields.
Sequence‐Designed Peptide Nanofibers Bridged Conjugation of Graphene Quantum Dots with Graphene Oxide for High Performance Electrochemical Hydrogen Peroxide Biosensor
Authors: Li Yang , Zhang Wensi , Zhang Lu , Li Jingfeng , Su Zhiqiang , Wei Gang
Published: December 2016

Motif‐designed peptide molecules have the unique property to form filamentous nanostructure and the ability to conjugate with other nanoscale building blocks such as graphene and nanoparticles to create functional nanomaterials. Here, the design of a novel functional peptide molecule is reported, which has the abilities to form peptide nanofibers (PNFs) and recognize with graphene quantum dots (GQDs) and graphene oxide (GO) nanosheet specifically. Based on the design of peptide sequence, the ternary GQD‐PNF‐GO nanohybrids are synthesized successfully. The created ternary GQD‐PNF‐GO nanohybrids are characterized by transmission electron microscopy and atomic force microscopy (AFM). To understand the formation mechanism of this ternary nanostructure, the interactions between GQD, PNF, and GO are further investigated by AFM‐based force spectroscopy. Moreover, it is found that the synthesized ternary GQD‐PNF‐GO nanohybrids show potential applications for high performance electrochemical hydrogen peroxide (H2O2) biosensor. This fabricated biosensor exhibits high sensitivity and selectivity, low detection limit, and wide linear range for sensing H2O2. It is believed that the strategies shown in this work such as the motif design of peptide and its self‐assembly on GO will benefit the further creation of functional binary and ternary nanomaterials, as well as the understanding of their self‐assembly and formation mechanisms.
Flexible Thermoelectric Generators Composed of n‐and p‐Type Silicon Nanowires Fabricated by Top‐Down Method
Authors: Choi Jinyong , Cho Kyoungah , Kim Sangsig
Published: December 2016

This study demonstrates the fabrication and characterization of a flexible thermoelectric (TE) power generator composed of silicon nanowires (SiNWs) fabricated by top‐down method and discusses its strain‐dependence analysis. The Seebeck coefficients of the p‐ and n‐type SiNWs used to form a pn‐module are 156.4 and −146.1 µV K−1, respectively. The maximum power factors of the p‐ and n‐type SiNWs are obtained as 8.79 and 8.87 mW (m K2)−1, respectively, under a convex bending of 1.11%, respectively; these are the largest values among the power factors hitherto reported for SiNWs. The dimensionless figure of merit (ZT) values of the SiNWs at room temperature are 6.8 × 10−2 and 6.7 × 10−2 for the convex bent p‐ and n‐type SiNWs, respectively, with a strain of 1.11%. The thermoelectric properties of the pn‐module and its component SiNWs are characterized under strain conditions ranging from −1.11% to 1.11%. The maximum Seebeck coefficient and power factor of the pn‐module are obtained as 448 µV K−1 and 14.2 mW (m K2)−1, respectively, under convex bending of 1.11%. Moreover, the mechanical stability of the TE characteristics of the pn‐module is demonstrated through a continuous bending test of 3000 cycles under convex bending of 0.66%.
Enlargement of Meckel's cave in patients with spontaneous cerebrospinal fluid leaks
Authors: Aaron Geoffrey P. , Illing Elisa , Lambertsen Zachary , Ritter Miles , Middlebrooks Erik H. , Cure Joel , Cho Do‐Yeon , Riley Kristen O. , Woodworth Bradford A.
Published: December 2016

Background

Spontaneous cerebrospinal fluid (CSF) leaks have imaging findings consistent with chronically elevated intracranial pressure, such as empty sella. Meckel's cave is a CSF‐filled space that houses the trigeminal ganglion at the cranial base. Our objective in this study was to evaluate “dilated” Meckel's cave as a radiologic sign in patients with elevated intracranial pressure spontaneous CSF leaks and compare the dimensions with those from a control cohort.

Methods

Meckel's cave dimensions were measured in patients with spontaneous CSF leaks and documented elevated intracranial pressure. A control group of subjects who underwent magnetic resonance imagine (MRI) scans for unrelated diagnoses were also evaluated. Subjects were included only if suitable MRIs with T2‐weighted sequences in the axial plane were available.

Results

Sixty‐three patients with spontaneous CSF leaks and 91 normal control patients were included in the study. There was significant (p < 0.05) enlargement in all measured dimensions (length and width) for the spontaneous CSF leak group. When evaluating area, spontaneous CSF leak subjects again showed significant enlargement compared with controls (0.81 ± 0.35 cm2 vs 0.52 ± 0.15 cm2; p < 0.0001). Average intracranial pressure measurements were 25.9 ± 9.0 cmH2O.

Conclusion

Patients with spontaneous CSF leaks have evidence of enlarged Meckel's caves. Evaluation of Meckel's cave dimensions should be included in preoperative imaging assessment as an additional indicator of chronically elevated intracranial pressure.
Luminescent Tungsten(VI) Complexes: Photophysics and Applicability to Organic Light‐Emitting Diodes and Photocatalysis
Authors: Yeung Kwan‐Ting , To Wai‐Pong , Sun Chenyue , Cheng Gang , Ma Chensheng , Tong Glenna So Ming , Yang Chen , Che Chi‐Ming
Published: December 2016

The synthesis, excited‐state dynamics, and applications of two series of air‐stable luminescent tungsten(VI) complexes are described. These tungsten(VI) complexes show phosphorescence in the solid state and in solutions with emission quantum yields up to 22 % in thin film (5 % in mCP) at room temperature. Complex 2 c, containing a 5,7‐diphenyl‐8‐hydroxyquinolinate ligand, displays prompt fluorescence (blue–green) and phosphorescence (red) of comparable intensity, which could be used for ratiometric luminescent sensing. Solution‐processed organic light‐emitting diodes (OLEDs) based on 1 d showed a stable yellow emission with an external quantum efficiency (EQE) and luminance up to 4.79 % and 1400 cd m−2 respectively. These tungsten(VI) complexes were also applied in light‐induced aerobic oxidation reactions.
Star PolyMOCs with Diverse Structures, Dynamics, and Functions by Three‐Component Assembly
Authors: Wang Yufeng , Gu Yuwei , Keeler Eric G. , Park Jiwon V. , Griffin Robert G. , Johnson Jeremiah A.
Published: December 2016

We report star polymer metal–organic cage (polyMOC) materials whose structures, mechanical properties, functionalities, and dynamics can all be precisely tailored through a simple three‐component assembly strategy. The star polyMOC network is composed of tetra‐arm star polymers functionalized with ligands on the chain ends, small molecule ligands, and palladium ions; polyMOCs are formed via metal–ligand coordination and thermal annealing. The ratio of small molecule ligands to polymer‐bound ligands determines the connectivity of the MOC junctions and the network structure. The use of large M12L24MOCs enables great flexibility in tuning this ratio, which provides access to a rich spectrum of material properties including tunable moduli and relaxation dynamics.
Iron‐Catalyzed Oxidative C−C and N−N Coupling of Diarylamines and Synthesis of Spiroacridines
Authors: Fritsche Raphael F. , Theumer Gabriele , Kataeva Olga , Knölker Hans‐Joachim
Published: December 2016

We describe iron‐catalyzed intermolecular oxidative coupling reactions of diarylamines to form substituted 2,2′‐bis(arylamino)biaryl compounds, tetraarylhydrazines, and 5,6‐dihydrobenzo[c]cinnolines with the same hexadecafluorinated iron–phthalocyanine catalyst. The mild formation of C−C or N−N bonds was controlled by the use of acidic or basic additives. In contrast to most iron‐catalyzed dehydrogenative coupling reactions, ambient air could be used as the sole oxidant. Moreover, iron(III) chloride hexahydrate promoted a one‐pot coupling and subsequent intramolecular dearomative coupling to give 10H‐spiro[acridine‐9,1′‐cyclohexa‐2′,5′‐dien‐4′‐ones].
Anodized Aluminum Oxide Templated Synthesis of Metal–Organic Frameworks Used as Membrane Reactors
Authors: Yu Yifu , Wu Xue‐Jun , Zhao Meiting , Ma Qinglang , Chen Junze , Chen Bo , Sindoro Melinda , Yang Jian , Han Shikui , Lu Qipeng , Zhang Hua
Published: December 2016

The incorporation of metal–organic frameworks (MOFs) into membrane‐shaped architectures is of great importance for practical applications. The currently synthesized MOF‐based membranes show many disadvantages, such as poor compatibility, low dispersity, and instability, which severely limit their utility. Herein, we present a general, facile, and robust approach for the synthesis of MOF‐based composite membranes through the in situ growth of MOF plates in the channels of anodized aluminum oxide (AAO) membranes. After being used as catalysis reactors, they exhibit high catalytic performance and stability in the Knoevenagel condensation reaction. The high catalytic performance might be attributed to the intrinsic structure of MOF‐based composite membranes, which can remove the products from the reaction zone quickly, and prevent the aggregation and loss of catalysts during reaction and recycling process.
Photo‐Modulated Therapeutic Protein Release from a Hydrogel Depot Using Visible Light
Authors: Basuki Johan S. , Qie Fengxiang , Mulet Xavier , Suryadinata Randy , Vashi Aditya V. , Peng Yong Y. , Li Lingli , Hao Xiaojuan , Tan Tianwei , Hughes Timothy C.
Published: December 2016

The use of biomacromolecular therapeutics has revolutionized disease treatment, but frequent injections are required owing to their short half‐life in vivo. Thus there is a need for a drug delivery system that acts as a reservoir and releases the drug remotely “on demand”. Here we demonstrate a simple light‐triggered local drug delivery system through photo‐thermal interactions of polymer‐coated gold nanoparticles (AuNPs) inside an agarose hydrogel as therapeutic depot. Localized temperature increase induced by the visible light exposure caused reversible softening of the hydrogel matrix to release the pre‐loaded therapeutics. The release profile can be adjusted by AuNPs and agarose concentrations, light intensity and exposure time. Importantly, the biological activity of the released bevacizumab was highly retained. In this study we demonstrate the potential application of this facile AuNPs/hydrogel system for ocular therapeutics delivery through its versatility to release multiple biologics, compatibility to ocular cells and spatiotemporal control using visible light.
Synthesis of Chiral Vicinal Diamines by Silver(I)‐Catalyzed Enantioselective Aminolysis of N‐Tosylaziridines
Authors: Chai Zhuo , Yang Pei‐Jun , Zhang Hu , Wang Shaowu , Yang Gaosheng
Published: December 2016

The kinetic resolution of 2‐aryl‐N‐tosylaziridines and the asymmetric desymmetrization of meso‐N‐tosylaziridines by ring openings with various primary and secondary anilines, and aliphatic amines as nucleophile have been realized by using a single silver(I)/chiral diphosphine complex as catalyst for the first time. The simple starting materials, broad scope, and easy scalability render this protocol a practical way to chiral vicinal diamine derivatives.
Investigation of Intrinsically Disordered Proteins through Exchange with Hyperpolarized Water
Authors: Kurzbach Dennis , Canet Estel , Flamm Andrea G. , Jhajharia Aditya , Weber Emmanuelle M. M. , Konrat Robert , Bodenhausen Geoffrey
Published: December 2016

Hyperpolarized water can selectively enhance NMR signals of rapidly exchanging protons in osteopontin (OPN), a metastasis‐associated intrinsically disordered protein (IDP), at near‐physiological pH and temperature. The transfer of magnetization from hyperpolarized water is limited to solvent‐exposed residues and therefore selectively enhances signals in 1H‐15N correlation spectra. Binding to the polysaccharide heparin was found to induce the unfolding of preformed structural elements in OPN.
Azidoperfluoroalkanes: Synthesis and Application in Copper(I)‐Catalyzed Azide–Alkyne Cycloaddition
Authors: Blastik Zsófia E. , Voltrová Svatava , Matoušek Václav , Jurásek Bronislav , Manley David W. , Klepetářová Blanka , Beier Petr
Published: December 2016

We report an efficient and scalable synthesis of azidotrifluoromethane (CF3N3) and longer perfluorocarbon‐chain analogues (RFN3; RF=C2F5, nC3F7, nC8F17), which enables the direct insertion of CF3 and perfluoroalkyl groups into triazole ring systems. The azidoperfluoroalkanes show good reactivity with terminal alkynes in copper(I)‐catalyzed azide–alkyne cycloaddition (CuAAC), giving access to rare and stable N‐perfluoroalkyl triazoles. Azidoperfluoroalkanes are thermally stable and the efficiency of their preparation should be attractive for discovery programs.
Conductance Switch of a Bromoplumbate Bistable Semiconductor by Electron‐Transfer Thermochromism
Authors: Sun Cai , Wang Ming‐Sheng , Li Pei‐Xin , Guo Guo‐Cong
Published: December 2016

Electron‐transfer (redox) thermochromism was successfully used for switching the conductance of semiconductors, by introducing a thermally active organic component into an inorganic semiconducting framework. A moisture‐resistant semiconductor {(MV)2[Pb7Br18]}n (MV2+=methyl viologen cation) has been prepared through an in situ synthetic method for MV2+. It features a rare 3D haloplumbate open framework and unprecedented electron‐transfer thermochromic behavior in haloplumbates. The electrical conductivity of this compound dropped significantly after coloration and restored after decoloration, which was satisfactorily explained by valence band XPS and theoretical data. This work not only offers a new approach to modify electrical properties of semiconductors without altering components or structures, but may lead to the development of over‐temperature color indicators, circuit overload protectors or photovoltaic materials.
Functionalized Natural Carbon‐Supported Nanoparticles as Excellent Catalysts for Hydrocarbon Production
Authors: Sun Jian , Guo Lisheng , Ma Qingxiang , Gao Xinhua , Yamane Noriyuki , Xu Hengyong , Tsubaki Noritatsu
Published: December 2016

We report a one‐pot and eco‐friendly synthesis of carbon‐supported cobalt nanoparticles, achieved by carbonization of waste biomass (rice bran) with a cobalt source. The functionalized biomass provides carbon microspheres as excellent catalyst support, forming a unique interface between hydrophobic and hydrophilic groups. The latter, involving hydroxyl and amino groups, can catch much more active cobalt nanoparticles on surface for Fischer–Tropsch synthesis than chemical carbon. The loading amount of cobalt on the final catalyst is much higher than that prepared with a chemical carbon source, such as glucose. The proposed concept of using a functionalized natural carbon source shows great potential compared with conventional carbon sources, and will be meaningful for other fields concerning carbon support, such as heterogeneous catalysis or electrochemical fields.
Transit trip distribution model considering land use differences between catchment areas
Authors: Wang Shuwei , Sun Lishan , Rong Jian , Hao Siyuan , Luo Wei
Published: December 2016

Sustainable land use planning and advanced public transport system are believed to be effective solutions to traffic congestion. To this end, it is important to reveal the relationship between transit ridership and land use. However, current Direct Ridership Models only focus on the relationship between single station's boarding volume and the corresponding catchment area land use. This paper analyzed the ridership distribution between transit stations by considering the land use difference between catchment areas. Land use difference was calculated from point of interest (POI) data extracted from an electronic map of Beijing; transit trip distribution volume was obtained from ‘automatic fare collection’ facility. After data specification, a transit ridership distribution model was proposed and calibrated. The calibration results suggest that land use difference has a directly proportional correlation with transit ridership distribution. The research findings build a bridge between detailed urban form and public transport, which is of significance for the further research of sustainable urban planning. Copyright © 2016 John Wiley & Sons, Ltd.
Effect of Glycosylation on the Biocatalytic Properties of Hydroxynitrile Lyase from the Passion Fruit, Passiflora edulis: A Comparison of Natural and Recombinant Enzymes
Authors: Nuylert Aem , Ishida Yuko , Asano Yasuhisa
Published: December 2016

A hydroxynitrile lyase from the passion fruit Passiflora edulis (PeHNL) was isolated from the leaves and showed high stability in biphasic co‐organic solvent systems for cyanohydrin synthesis. Cyanohydrins are important building blocks for the production of fine chemicals and pharmaceuticals. Thus, to enhance production yields of PeHNL for industrial applications, we cloned and expressed recombinant PeHNL in Escherichia coli BL21(DE3) and Pichia pastoris GS115 cells without a signal peptide sequence. The aim of this study is to determine the effect of N‐glycosylation on enzyme stability and catalytic properties in microbial expression systems. PeHNL from leaves (PeHNL‐N) and that expressed in P. pastoris (PeHNL‐P) were glycosylated, whereas that expressed in E. coli (PeHNL‐E) was not. The enzymes PeHNL‐N and PeHNL‐P showed much better thermostability, pH stability, and organic solvent tolerance than the deglycosylated enzyme PeHNL‐E and the deglycosylated mutant N105Q from P. pastoris (PeHNL‐P‐N105Q). The glycosylated PeHNL‐P also efficiently performed transcyanation of (R)‐mandelonitrile with a 98 % enantiomeric excess in a biphasic system with diisopropyl ether. These data demonstrate the efficacy of these methods for improving enzyme expression and stability for industrial application through N‐glycosylation.
H2 Generation with (Mixed) Plasmonic Cu/Au‐TiO2 Photocatalysts: Structure–Reactivity Relationships Assessed by in situ Spectroscopy
Authors: Priebe Jacqueline B. , Radnik Jörg , Kreyenschulte Carsten , Lennox Alastair J. J. , Junge Henrik , Beller Matthias , Brückner Angelika
Published: December 2016

Monometallic Cu and bimetallic Cu/Au‐TiO2 catalysts were prepared by impregnation (IM) and reductive precipitation (RP) methods in sequential (SP) and simultaneous mode (CP) and tested for photocatalytic H2 generation from H2O/methanol mixtures with visible (400–700 nm) and UV/Vis light (320–500 nm). Comprehensive studies by high‐resolution (HR)‐STEM, X‐ray photoelectron spectroscopy (XPS), and different in situ methods (X‐ray absorption near‐edge structure (XANES), UV/Vis, and EPR spectroscopy) revealed that IM leads to dispersed surface Cu species with no clear particle formation, which is poorly active under visible light, whereas plasmonic Cu0 nanoparticles formed by RP are about three times more active under the same conditions. In Cu/Au‐TiO2 catalysts prepared by RP‐SP, highly dispersed Cu surface species boost H2 production under UV/Vis light, owing to the effective separation within TiO2 and electron trapping by Cu, whereas small Cu0 and Au0 particles remain widely separated. When Cu/Au‐TiO2 catalysts are prepared by RP‐CP, mixed Cu/Au particles of uniform size (4–8 nm) provide the highest H2 evolution rates under visible light, owing to effective surface plasmon resonance absorption.
4‐Nitrophenol Reduction by a Single Platinum Palladium Nanocube Caged within a Nitrogen‐Doped Hollow Carbon Nanosphere
Authors: Zhang Chunmei , Zhang Ruizhong , He Shuijian , Li Lei , Wang Xiaodan , Liu Minmin , Chen Wei
Published: December 2016

The improvement of the utilization efficiency and the enhancement of the catalytic activity and stability of precious‐metal‐based nanocatalysts is a hot topic in the field of catalysis. In the present study, a single‐nanoparticle catalyst with a high stability is realized by confining a single surface‐cleaned PtPd alloy nanocube within a N‐doped hollow carbon nanosphere (PtPd@N‐HCS). The microporous carbon shell makes the encaged PtPd nanocube accessible to the reacting molecules. Compared with PtPd nanocubes protected by polyvinylpyrrolidone (PVP‐PtPd) and N‐doped carbon spheres, PtPd@N‐HCS exhibited a better catalytic performance towards 4‐nitrophenol reduction. Under the catalysis of PtPd@N‐HCS, 4‐nitrophenol can be reduced completely to 4‐aminophenol (100 %) in 2 min; however, only 50 and 20 % of 4‐nitrophenol was degraded in 2 min with PVP‐PtPd and N‐HCS as catalysts. Moreover, as a result of the confinement of PtPd nanocubes in hollow nanospheres, PtPd@N‐HCS showed a high catalytic stability with 100 % conversion maintained over at least four cycles.
Robust Colloidal Nanoparticles of Pyrrolopyrrole Cyanine J‐Aggregates with Bright Near‐Infrared Fluorescence in Aqueous Media: From Spectral Tailoring to Bioimaging Applications
Authors: Yang Cangjie , Wang Xiaochen , Wang Mingfeng , Xu Keming , Xu Chenjie
Published: December 2016

Colloidal nanoparticles (NPs) containing near‐infrared‐fluorescent J‐aggregates (JAGGs) of pyrrolopyrrole cyanines (PPcys) stabilized by amphiphilic block co‐polymers were prepared in aqueous medium. JAGG formation can be tuned by means of the chemical structure of PPcys, the concentration of chromophores inside the polymeric NPs, and ultrasonication. The JAGG NPs exhibit a narrow emission band at 773 nm, a fluorescence quantum yield comparable to that of indocyanine green, and significantly enhanced photostability, which is ideal for long‐term bioimaging.
Thermodynamic Insights on a Bistable Acid–Base Switchable Molecular Shuttle with Strongly Shifted Co‐conformational Equilibria
Authors: Ragazzon Giulio , Credi Alberto , Colasson Benoit
Published: December 2016

Bistable [2]rotaxanes in which the affinities of the two stations can be reversed form the basis of molecular shuttles. Gaining quantitative information on such rotaxanes in which the ring distribution between the two stations is largely nonsymmetric has proven to be very challenging. Herein, we report on two independent experimental methodologies, based on luminescence lifetime measurements and acid–base titrations, to determine the relative populations of the two co‐conformations of a [2]rotaxane. The assays yield convergent results and are sensitive enough to measure an equilibrium constant (K≈4000) out of reach for NMR spectroscopy. We also estimate the ring distribution constant in the switched (deprotonated) state (K′<10−4), and report the highest positional efficiency for stimuli‐induced shuttling to date (>99.92 %). Finally, our results show that the pKa of the pH‐responsive station depends on the ring affinity of the pH‐insensitive station, an observation that paves the way for the design of new artificial allosteric systems.
Deutschland braucht Chemie‐Gründungen
Authors: Bengs Holger
Published: December 2016

Deutschland braucht mehr Unternehmergeist in einem der bedeutendsten Industriezweige des Landes, der Chemie. Das gilt für tatkräftiges Handeln in großen Unternehmen gleichermaßen wie an den Hochschulen und Forschungsinstituten mit ihren technologischen Keimzellen für neue Unternehmen. Viele Jahre dominierten Begriffe wie Nano‐ oder Biotechnologie das Umfeld Entrepreneurship [1]. Es ist Zeit, über die Verantwortung der Kreativen und Macher in der Chemie zu sprechen.
Erkennt die Signale
Authors: Groß Michael
Published: December 2016

Damit ein frisch hergestelltes Protein auch dort ankommt, wo es benötigt wird, haben unsere Zellen das Signalerkennungspartikel. Seine Funktionsweise wurde an In‐vitro‐Modellsystemen bereits in den 1990er Jahren erkannt und untersucht, doch nun kann man sein gesamtes Kontaktnetzwerk in der lebenden Zelle analysieren. Dies gelang jetzt sowohl bei der Hefe als auch bei Bakterien.