bluuebunny/crossref_metadata_2025 huggingface dataset:
Spiro‐Phenylpyrazole‐9,9′‐Thioxanthene Analogues as Hole‐Transporting Materials for Efficient Planar Perovskite Solar Cells
Authors: Wang Yang , Zhu Zonglong , Chueh Chu‐Chen , Jen Alex K.‐Y. , Chi Yun
Published: June 2017

Perovskite solar cells have emerged as a promising technique for low‐cost, light weight, and highly efficient photovoltaics. However, they still largely rely on 2,2′,7,7′‐tetrakis(N,N‐di‐p‐methoxyphenylamine)‐9,9′‐spirobifluorene (Spiro‐OMeTAD) to serve as hole‐transporting materials (HTMs). Here, a series of HTMs with small molecular weight is designed, which are constructed on a spiro core involving phenylpyrazole and a second heteroaromatics, i.e., xanthene (O atom), thioxanthene (S atom), and acridine (N atom). Through varying from phenylpyrazole substituted xanthene (PPyra‐XA), thioxanthene (PPyra‐TXA), to acridine (PPyra‐ACD), their optical and electrochemical properties, hole mobilities, and the photovoltaic performance are optimized. As a consequence, PPyra‐TXA based device exhibits the highest power conversion efficiency (PCE) of 18.06%, outperforming that of Spiro‐OMeTAD (16.15%), which could be attributed to the enhancement of hole mobility exerted by the thioxanthene. In addition, the dopant‐free device shows PCE of 11.7%. These results open a new direction for designing spiro‐HTMs by simple modification of chemical structures.
Specific psychosocial exposures for workers’ mental health: A population‐based study
Authors: Navarro Albert , Utzet Mireia , Salas Sergio , Llorens Clara , Molinero‐Ruiz Emilia , Moncada Salvador
Published: June 2017

Background

In order to plan interventions it is important to obtain evidence on the relation between a health outcome and specific exposures. However, there are few studies that identify the effect of specific psychosocial work exposures on poor mental health. This is the aim of this study.

Methods

Population‐based cross‐sectional study in Catalonia. We estimated prevalence ratios (PR) of minor psychiatric disorder associated with several psychosocial work exposures.

Results

The items with highest PR were “Are there times when you need to be at work and at home at the same time?” (PR = 1.81), “Are you worried about a variation in your salary?” (PR = 1.77), “Is your work emotionally demanding?” (PR = 1.65) and “Are you worried about it being difficult for you to find another job if you became unemployed?” (PR = 1.51).

Conclusions

This study could be useful in order to begin planning interventions on specific psychosocial exposures to protect mental health in the workplace.
Evidence of direct reciprocity, but not of indirect and generalized reciprocity, in the grooming exchanges of wild Barbary macaques (Macaca sylvanus)
Authors: Molesti Sandra , Majolo Bonaventura
Published: June 2017

Reciprocity is one of the mechanisms that have been proposed to explain the exchange of social behaviors, such as grooming, in animals. Reciprocity assumes that individuals act as the donor and recipient of grooming and switch roles over time to balance the benefits and costs of this behavior. Three main patterns of reciprocity may follow a grooming given: (i) direct reciprocity, where the former recipient returns the grooming to the former donor; (ii) indirect reciprocity, where another individual returns the grooming to the former donor; and (iii) generalized reciprocity, where the former recipient returns the grooming to another individual. While there is evidence that direct reciprocity plays an important role in various species of animals, the role of indirect and generalized reciprocity is less clear and has been rarely analyzed. We tested the role of direct, indirect, and generalized reciprocity in explaining grooming exchanges of wild Barbary macaques, by analyzing the temporal contingency between giving and receiving grooming. We collected the occurrence and latency of the three types of grooming reciprocation during 1 hr long focal sessions run simultaneously on two partners who just stopped grooming (post‐grooming session) or who were in proximity (i.e., within 1.5 m) without grooming each other (control session). We ran the analyses on 284 post‐grooming and 63 control sessions. The results revealed a temporal contingency of grooming interactions exchanged according to direct reciprocity but not according to indirect or generalized reciprocity. Our results indicate that grooming distribution in Barbary macaques is partner‐specific. We discuss the possible role of cognition and emotions in explaining direct reciprocity in animals.
Cutaneous nerve biomarkers in transthyretin familial amyloid polyneuropathy
Authors: Ebenezer Gigi J. , Liu Ying , Judge Daniel P. , Cunningham Kelly , Truelove Shaun , Carter Noel D. , Sebastian Blessan , Byrnes Kelly , Polydefkis Michael
Published: June 2017

Objective

To determine the utility of skin biopsies as a biomarker of disease severity in subjects with amyloid neuropathy.

Methods

Five groups of patients were studied: (1) transthyretin (TTR) familial amyloidotic polyneuropathy (FAP; n = 20), (2) TTR mutation carriers without peripheral neuropathy (TTR‐noPN; n = 10), (3) healthy controls (n = 20), (4) diabetic neuropathy disease controls (n = 20), and (5) patients with light‐chain (AL) amyloid (n = 2). All subjects underwent neurological examination and 3mm skin biopsies. Sections were stained with anti‐PGP9.5, anti‐TTR, and Congo red. Intraepidermal (IENFD), sweat gland (SGNFD), and pilomotor nerve fiber densities (PMNFD) were measured. Correlations between the amount of amyloid present (amyloid burden), fiber subtype, and Neuropathy Impairment Score in the Lower Limbs (NIS‐LL) were evaluated.

Results

IENFD, SGNFD, and PMNFD were all significantly reduced in TTR‐FAP patients versus healthy controls, whereas TTR‐noPN subjects had intermediate reductions. Lower nerve fiber densities were associated with NIS‐LL (p < 0.001). Congo red staining revealed brilliant red amyloid deposits confirmed by apple‐green birefringence within dermal collagen, sweat glands, and arrector pili that engulfed axons. The diagnostic sensitivity and specificity to detect amyloid in skin were 70% and 100%. Both AL amyloidosis and 2 of 10 TTR‐noPN subjects were Congo red–positive. Amyloid burden correlated with IENFD (r = −0.63), SGNFD (r = −0.67), PMNFD (r = −0.50), and NIS‐LL (r = −0.57). Wild‐type TTR staining was less prominent in TTR‐FAP patients.

Interpretation

Cutaneous amyloid was detected in 70% of TTR‐FAP and 20% of TTR‐noPN subjects. Amyloid burden correlated strongly with reductions in IENFD, SGNFD, PMNFD, and NIS‐LL. Skin is an attractive tissue to establish an amyloid diagnosis, and amyloid burden has potential as a biomarker to detect treatment effect in TTR‐FAP drug trials. Ann Neurol 2017;82:44–56
Thermally Stable and Regenerable Platinum–Tin Clusters for Propane Dehydrogenation Prepared by Atom Trapping on Ceria
Authors: Xiong Haifeng , Lin Sen , Goetze Joris , Pletcher Paul , Guo Hua , Kovarik Libor , Artyushkova Kateryna , Weckhuysen Bert M. , Datye Abhaya K.
Published: June 2017

Ceria (CeO2) supports are unique in their ability to trap ionic platinum (Pt), providing exceptional stability for isolated single atoms of Pt. The reactivity and stability of single‐atom Pt species was explored for the industrially important light alkane dehydrogenation reaction. The single‐atom Pt/CeO2 catalysts are stable during propane dehydrogenation, but are not selective for propylene. DFT calculations show strong adsorption of the olefin produced, leading to further unwanted reactions. In contrast, when tin (Sn) is added to CeO2, the single‐atom Pt catalyst undergoes an activation phase where it transforms into Pt–Sn clusters under reaction conditions. Formation of small Pt–Sn clusters allows the catalyst to achieve high selectivity towards propylene because of facile desorption of the product. The CeO2‐supported Pt–Sn clusters are very stable, even during extended reaction at 680 °C. Coke formation is almost completely suppressed by adding water vapor to the feed. Furthermore, upon oxidation the Pt–Sn clusters readily revert to the atomically dispersed species on CeO2, making Pt–Sn/CeO2 a fully regenerable catalyst.
Zinc–Zinc Double Bonds: A Theoretical Study
Authors: Echeverría Jorge , Falceto Andrés , Alvarez Santiago
Published: June 2017

While double bonds are known for transition metals of Groups 9 and 10 as well as for boron and p‐block elements of Groups 14–16, Zn sits in a small region of the periodic table with no well‐characterized double bonds. A qualitative reasoning indicates that zero‐valent zinc has the potential to form Zn=Zn double bonds. A computational study in search for complexes that might showcase this new bond type is presented here.
Fusion von Liposomen in einer DNA‐programmierten Kaskade
Authors: Löffler Philipp M. G. , Ries Oliver , Rabe Alexander , Okholm Anders H. , Thomsen Rasmus P. , Kjems Jørgen , Vogel Stefan
Published: June 2017

Synthetisch hergestellte und funktionalisierte nanoskopische Behälter werden in der Synthesebiologie eingesetzt, um räumlich abgegrenzte chemische Prozesse auszuführen. Systeme mit zunehmender Komplexität erfordern Methoden zur räumlichen und zeitlichen Kontrolle der eingeschlossenen Spezies. Hier wird diese Herausforderung durch ein DNA‐kodiertes Design für die aufeinanderfolgende Fusion mehrerer Liposompopulationen adressiert. Eine Liposomfusion in drei Stufen wurde durch orthogonal hybridisierende Paare membranverankerter Oligonukleotide kontrolliert. Jedes Fusionsereignis führte zu einer effizienten Vermischung der eingeschlossenen Volumen und zur Übertragung eines Oligonukleotides, das durch molekulare Erkennung die Einleitung der nachfolgenden Stufe ermöglicht. Im Unterschied zur proteingesteuerten Vesikelfusion in eukaryotischen Zellen und Synapsen nutzt die hier vorgestellte künstliche Fusionskaskade das vielseitige Kodierungspotenzial der DNA‐Hybridisierung.
Stereoretentive Olefinmetathese: ein Weg zur kinetischen Selektivität
Authors: Montgomery T. Patrick , Ahmed Tonia S. , Grubbs Robert H.
Published: June 2017

Die Olefinmetathese ist ein wertvolles Verfahren für Wissenschaft und Industrie. In letzter Zeit rückte die stereoretentive Olefinmetathese als eine Methode für die selektive Erzeugung von sowohl E‐ als auch Z‐Olefinen in den Fokus. In früheren Untersuchungen wurde nachgewiesen, dass die stereochemische Konfiguration der Ausgangsolefine zu Anfang der Umwandlung beibehalten wird. Als sich die Reaktion dem Gleichgewichtszustand näherte, wurden jedoch thermodynamische E/Z‐Verhältnisse erreicht. Bei neueren Untersuchungen lag das Hauptaugenmerk auf der Synthese von Katalysatoren, mit denen die inhärente thermodynamische Präferenz eines Olefins überwunden und ein kinetisch begünstigtes Olefinisomer erzeugt werden kann. Diese Berichte führten zur Entwicklung von stereoretentiven Katalysatoren, mit denen nicht nur selektiv Z‐Olefine erhalten werden, sondern auch E‐Olefine. Fortschritte bei der stereoretentiven Olefinmetathese unter Verwendung von Wolfram‐, Ruthenium‐ und Molybdänkatalysatoren werden hier dargelegt.
Gold(Core)–Lead(Shell) Nanoparticle‐Loaded Titanium(IV) Oxide Prepared by Underpotential Photodeposition: Plasmonic Water Oxidation
Authors: Negishi Ryo , Naya Shin‐ichi , Kobayashi Hisayoshi , Tada Hiroaki
Published: June 2017

Underpotential photodeposition of Pb yields an ultrathin shell layer on the Au(111) surface of Au nanoparticle(NP)‐loaded TiO2 (Au/TiO2) with heteroepitaxial nanojunctions. The localized surface plasmon resonance of Au/TiO2 undergoes no damping with the Pb‐shell formation, and the Pb shell offers resistance to aerobic oxidation. Mesoporous films comprising the Au(core)–Pb(shell) NP‐loaded TiO2 and unmodified Au/TiO2 were formed on fluorine‐doped tin oxide (FTO) electrode. Using them as the photoanode, photoelectrochemical cells were fabricated, and the photocurrent was measured under illumination of simulated sunlight. The photocurrent for water splitting is dramatically enhanced by the Pb‐shell formation. The photoelectrochemical measurements of the hot‐electron lifetime and density functional theory calculations for model clusters indicate that the Pb‐shell effect originates from the charge separation enhancement.
A DNA‐Programmed Liposome Fusion Cascade
Authors: Löffler Philipp M. G. , Ries Oliver , Rabe Alexander , Okholm Anders H. , Thomsen Rasmus P. , Kjems Jørgen , Vogel Stefan
Published: June 2017

Chemically engineered and functionalized nanoscale compartments are used in bottom‐up synthetic biology to construct compartmentalized chemical processes. Progressively more complex designs demand spatial and temporal control over entrapped species. Here, we address this demand with a DNA‐encoded design for the successive fusion of multiple liposome populations. Three individual stages of fusion are induced by orthogonally hybridizing sets of membrane‐anchored oligonucleotides. Each fusion event leads to efficient content mixing and transfer of the recognition unit for the subsequent stage. In contrast to fusion‐protein‐dependent eukaryotic vesicle processing, this artificial fusion cascade exploits the versatile encoding potential of DNA hybridization and is generally applicable to small and giant unilamellar vesicles. This platform could thus enable numerous applications in artificial cellular systems and liposome‐based synthetic pathways.
Enantioselective Hydroazidation of Trisubstituted Non‐Activated Alkenes
Authors: Meyer Daniel , Renaud Philippe
Published: June 2017

A one‐pot procedure for the enantioselective hydroazidation of non‐activated trisubstituted alkenes is described. Hydroboration with monoisopinocampheylborane (IpcBH2) provides dialkylboranes that are in situ selectively converted into monoalkyl‐substituted catecholboranes; these undergo radical azidation upon treatment with benzenesulfonyl azide and a radical initiator. Enantiomerically enriched azides were thus obtained in yields of 59–81 % and enantioselectivities of up to 94:6 e.r. (98:2 e.r. if the intermediate dialkylborane is purified by crystallization). A rapid access to enantiomerically pure (+)‐rodocaine is also described. The use of other arenesulfonyl radical traps enables enantioselective hydroallylation, hydrosulfanylation, and hydrobromination reactions with yields of 71–86 %.
Loosening of Lipid Packing Promotes Oligoarginine Entry into Cells
Authors: Murayama Tomo , Masuda Toshihiro , Afonin Sergii , Kawano Kenichi , Takatani‐Nakase Tomoka , Ida Hiroki , Takahashi Yasufumi , Fukuma Takeshi , Ulrich Anne S. , Futaki Shiroh
Published: June 2017

Despite extensive use of arginine‐rich cell‐penetrating peptides (CPPs)—including octaarginine (R8)—as intracellular delivery vectors, mechanisms for their internalization are still under debate. Lipid packing in live cell membranes was characterized using a polarity‐sensitive dye (di‐4‐ANEPPDHQ), and evaluated in terms of generalized polarization. Treatment with membrane curvature‐inducing peptides led to significant loosening of the lipid packing, resulting in an enhanced R8 penetration. Pyrenebutyrate (PyB) is known to facilitate R8 membrane translocation by working as a hydrophobic counteranion. Interestingly, PyB also actively induced membrane curvature and perturbed lipid packing. R8 is known to directly cross cell membranes at elevated concentrations. The sites of R8 influx were found to have looser lipid packing than surrounding areas. Lipid packing loosening is proposed as a key factor that governs the membrane translocation of CPPs.
Quantum‐Assisted Metrology of Neutral Vitamins in the Gas Phase
Authors: Mairhofer Lukas , Eibenberger Sandra , Cotter Joseph P. , Romirer Marion , Shayeghi Armin , Arndt Markus
Published: June 2017

It has recently been shown that matter‐wave interferometry can be used to imprint a periodic nanostructure onto a molecular beam, which provides a highly sensitive tool for beam displacement measurements. Herein, we used this feature to measure electronic properties of provitamin A, vitamin E, and vitamin K1 in the gas phase for the first time. The shift of the matter‐wave fringes in a static electric field encodes the molecular susceptibility and the time‐averaged dynamic electric dipole moment. The dependence of the fringe pattern on the intensity of the central light‐wave diffraction grating was used to determine the molecular optical polarizability. Comparison of our experimental findings with molecular dynamics simulations and density functional theory provides a rich picture of the electronic structures and dynamics of these biomolecules in the gas phase with β‐carotene as a particularly interesting example.
Race/Ethnicity and Cardiovascular Events Among Patients With Systemic Lupus Erythematosus
Authors: Barbhaiya Medha , Feldman Candace H. , Guan Hongshu , Gómez‐Puerta Jose A. , Fischer Michael A. , Solomon Daniel H. , Everett Brendan , Costenbader Karen H.
Published: June 2017

Objective

Systemic lupus erythematosus (SLE) is more prevalent and results in more severe outcomes among blacks, Asians, and Hispanics than among whites. Cardiovascular disease (CVD) is the leading cause of death among SLE patients. We undertook this study to examine racial/ethnic variations in risk of CVD events among SLE patients.

Methods

Within the Medicaid Analytic eXtract from 2000 to 2010, we identified patients ages 18–65 years with SLE (≥3 International Classification of Diseases, Ninth Revision 710.0 codes, ≥30 days apart) and with ≥12 months of continuous enrollment. Subjects were followed up from the index date to the first CVD event (myocardial infarction [MI] or stroke), death, disenrollment, loss to follow‐up, or end of follow‐up period. Race/ethnicity‐specific annual CVD event rates were calculated. Cox regression models estimated hazard ratios (HRs) with 95% confidence intervals (95% CIs), accounting for competing risk of death and adjusting for baseline demographics and comorbidities.

Results

Of 65,788 SLE patients, 93.1% were women and ∼42% were black, 38% were white, 16% were Hispanic, 3% were Asian, and 1% were American Indian/Alaska Native. Mean ± SD follow‐up was 3.8 ± 3.1 years. CVD event rates were highest among blacks (incidence rate [IR] 10.57 [95% CI 9.96–11.22]) and lowest among Asians (IR 6.63 [95% CI 4.97–8.85]). After multivariable adjustment, risk of CVD events was increased among blacks (HR 1.14 [95% CI 1.03–1.26]) compared to whites. Hispanics and Asians had a lower risk of MI (HR 0.61 [95% CI 0.48–0.77] and HR 0.57 [95% CI 0.34–0.96], respectively), while blacks and Hispanics had a higher risk of stroke (HR 1.31 [95% CI 1.15–1.49] and HR 1.22 [95% CI 1.03–1.44], respectively).

Conclusion

Among SLE patients enrolled in Medicaid, the risk of MI was lower among Hispanics and Asians compared to whites, while the risk of stroke was elevated among blacks and Hispanics compared to whites.
Transaminase Levels and Hepatic Events During Tocilizumab Treatment: Pooled Analysis of Long‐Term Clinical Trial Safety Data in Rheumatoid Arthritis
Authors: Genovese Mark C. , Kremer Joel M. , van Vollenhoven Ronald F. , Alten Rieke , Scali Juan Jose , Kelman Ariella , Dimonaco Sophie , Brockwell Laura
Published: June 2017

Objective

To investigate liver enzyme abnormalities and hepatic adverse events (AEs) during long‐term tocilizumab treatment for rheumatoid arthritis in clinical trials.

Methods

Data were pooled from patients who received intravenous tocilizumab (4, 8, or 10 mg/kg with or without disease‐modifying antirheumatic drugs [DMARDs]) in phase III or IV clinical trials, long‐term extensions, and a pharmacology study. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were measured routinely in these trials. AE rates were measured per 100 patient‐years of tocilizumab exposure for this pooled analysis.

Results

Overall, 16,204.8 patient‐years of tocilizumab exposure (mean ± SD duration of exposure 3.9 ± 2.0 years) were evaluated for 4,171 patients. ALT and AST elevations greater than the upper limit of normal (ULN) occurred in 70.6% and 59.4% of patients, respectively. ALT/AST elevations were >1–3× ULN in 59%/55% of patients, >3–5× ULN in 8.9%/3.3% of patients, and >5× ULN in 2.9%/0.9% of patients. Most elevations occurred during the first year of treatment. Single ALT/AST elevations >3× ULN occurred in 7.7%/3.6% of patients, and ≥2 consecutive elevations >3× ULN occurred in 1.9%/0.4% of patients. Elevations >3× ULN returned to normal in 80% of patients (median of 5.6 weeks to normalization). A total of 2.5% of patients withdrew from tocilizumab treatment following ALT/AST elevations. A total of 7 hepatic serious AEs (SAEs) (0.04 per 100 patient‐years [95% confidence interval 0.02–0.09]) occurred in the tocilizumab studies.

Conclusion

Transaminase elevations with tocilizumab were frequent, but rates of hepatic SAEs were low in this clinical trial data set. Regular monitoring, with dose adjustment of tocilizumab/DMARDs for persistent elevations, is recommended.
A Condition for Boundedness of Solutions of Bidimensional Switched Affine Systems With Multiple Foci and Centers
Authors: Zhu Liying
Published: June 2017

This paper studies boundedness of solutions of bidimensional switched affine linear systems. Every subsystem of the systems has a single stable/ unstable focus/ center and all the equilibria pairwise differ. By using the multiple polar coordinate systems method, this paper proposes a condition of boundedness of solutions of such switched systems under periodic/ quasi‐periodic switching paths. The condition is also shown a sufficient condition of global asymptotic region stability of such switched systems with respect to a region containing all multiple equilibria. A global asymptotic region‐stabilizing control, a periodic/ quasi‐periodic switching path, and a corresponding algorithm are all designed for such switched control systems. An illustrative example demonstrates the effectiveness and practicality of our new results.
Dead‐beat regulation of mechanical juggling systems
Authors: Menini Laura , Possieri Corrado , Tornambè Antonio
Published: June 2017

In this paper, mechanical systems subject to impacts and contacts, that would be not controllable if the impacts were absent (usually called jugglers), are considered. On the basis of an algorithm taken from the literature and of a new procedure to determine a reference trajectory for such a class of systems, a fully algorithmic procedure, able to compute a control input that achieves dead–beat regulation of the “uncontrollable” subsystem just by using impacts, is given. Such a procedure exploits some tools borrowed from algebraic geometry that allow to solve parametric systems of equalities and inequalities. A practical example of application of the given procedure is reported.
Improved Controller Design for Uncertain Positive Systems and its Extension to Uncertain Positive Switched Systems
Authors: Zhang Junfeng , Zhao Xudong , Zhang Ridong , Chen Yun
Published: June 2017

This paper is concerned with the controller design of uncertain positive systems. First, we decompose the feedback gain matrix Km×n into m×n non‐negative components and m×n non‐positive components. For the non‐negative components, each component contains only one positive element and the other elements are zero. Similarly, each non‐positive component contains only one negative element and the other ones are zero. Then, a simple and effective controller design approach of uncertain positive systems is proposed by incorporating the decomposed feedback gain matrix into the resulting closed‐loop systems and further applied to uncertain positive switched systems. It is shown that the designed controller is less conservative compared with those in the literature. Finally, a numerical example is provided to verify the validity of the proposed design.
Decrease in short‐latency afferent inhibition during corticomotor postexercise depression following repetitive finger movement
Authors: Miyaguchi Shota , Kojima Sho , Sasaki Ryoki , Kotan Shinichi , Kirimoto Hikari , Tamaki Hiroyuki , Onishi Hideaki
Published: June 2017

Introduction

This study aimed to clarify cortical circuit mechanisms contributing to corticomotor excitability during postexercise depression (PED) following repetitive nonfatiguing movement. We investigated changes in short‐latency afferent inhibition (SAI) and short‐interval intracortical inhibition (SICI) by paired‐pulse transcranial magnetic stimulation (TMS) during PED.

Methods

A total of 16 healthy subjects performed repetitive abduction movements of the right index finger at 2.0 Hz for 6 min at 10% maximum voluntary contraction. We measured SAI evoked by pairing ulnar nerve stimulation with TMS (interstimulus interval, 22 ms) before and during PED (n = 10, experiment 1). We also measured SICI evoked by paired TMS (interstimulus interval, 2 ms) at 80% resting motor threshold (n = 10, experiment 2), and at 80% active motor threshold (n = 8, experiment 3) before and during PED.

Results

Single motor evoked potential amplitude significantly decreased 1–2 min after the movement task in all experiments, indicating reliable PED induction. In experiment 1, SAI significantly decreased (disinhibited) 1–2 min during PED, whereas in experiments 2 and 3, SICI showed no significant change during PED.

Conclusion

This study suggests that cholinergic inhibitory circuit activity decreases during PED following repetitive nonfatiguing movement, whereas GABAA circuit activity remains stable.
MyMOOCSpace: A cloud‐based mobile system to support effective collaboration in higher education online courses
Authors: Ramírez‐Donoso Luis , Rojas‐Riethmuller Juan S. , Pérez‐Sanagustín Mar , Neyem Andrés , Alario‐Hoyos Carlos
Published: June 2017

In recent years, institutions of higher education have been using Massive Open Online Courses (MOOCs) as an alternative to enhance and innovate traditional classroom practices. One of the approaches to this type of innovation consists of using the platforms where MOOCs are hosted for the development of courses that are aligned to their on‐campus curricular contents. They are known as Small Private Online Courses (SPOCs), which allow online access to knowledge for groups of students with a well‐defined profile. The platforms where MOOCs (and SPOCs) are hosted have been designed to support large volumes of data and visits. However, these platforms present important limitations regarding the implementation of collaborative learning activities. To address this problem, this article presents MyMOOCSpace, a cloud‐based mobile system aimed at supporting effective collaboration in MOOCs, by combining key aspects of collaboration from the research area of Computer Supported Collaborative Learning (CSCL) with game‐based dynamics. MyMOOCSpace has been tested in three quasi‐experiments that were run in four Latin‐American universities with a total of 68 participants. The objective was to assess its usability and its effect in enhancing collaboration among students in a SPOC. The results obtained on usability show that MyMOOCSpace is easy to use, and that participants felt pleased with while using it. Finally, it was observed that MyMOOCSpace managed to enhance interaction and collaboration among students.
Data science in education: Big data and learning analytics
Authors: Klašnja‐Milićević Aleksandra , Ivanović Mirjana , Budimac Zoran
Published: June 2017

This paper considers the data science and the summaries significance of Big Data and Learning Analytics in education. The widespread platform of making high‐quality benefits that could be achieved by exhausting big data techniques in the field of education is considered. One principal architecture framework to support education research is proposed.
Antioxidant and Proteinase Inhibitory Activities of Selected Poppy (Papaver somniferum L.) Genotypes
Authors: Krošlák Erik , Maliar Tibor , Nemeček Peter , Viskupičová Jana , Maliarová Mária , Havrlentová Michaela , Kraic Ján
Published: June 2017

Poppy seeds (Papaver somniferum L.) belong to tasty food ingredients however, they should be considered also as valuable source of biologically active compounds. Content of selected metabolites, antioxidant and proteinase inhibitory activities were analyzed in vitro in extracts from seeds of fifteen poppy genotypes. Considerable variation in all parameters was detected within the set of analyzed poppy genotypes. The genotype Major expressed the highest antioxidant activity determined by all four methodological approaches (DPPH, ABTS, FRAP, RP). The genotype MS 423 exhibited the highest inhibitory activities against trypsin, thrombin and collagenase. Very specific position among all had the genotype Redy. Its grain extract reached significantly high levels in 9 out of 14 measured parameters (TPC, TFC, TTC, TAC, FRAP, RP, inhibitory activities against trypsin, thrombin, collagenase). Edible grains of poppy are valuable source of natural compounds which may be beneficial in pathological states associated with oxidative stress or increased proteinase activities.
A General Strategy for Open‐Flask Alkene Isomerization by Ruthenium Hydride Complexes with Non‐Redox Metal Salts
Authors: Lv Zhanao , Chen Zhuqi , Hu Yue , Zheng Wenrui , Wang Haibin , Mo Wanling , Yin Guochuan
Published: June 2017

A homogenous metal hydride (M−H) catalyst for isomerization normally requires rigorous air‐free techniques. Here, we demonstrate a highly efficient protocol in which simple non‐redox metal ions as Lewis acids can promote olefin isomerization dramatically with a commercially available RuH2(CO)(PPh3)3 complex in an open‐flask system. Isomerization can be accomplished within a short time, and a satisfactory selectivity for different types of unsaturated compounds can be obtained. Meanwhile, an excellent turnover number up to 17208 was achieved under air, and open‐flask gram‐scale experiments further demonstrated the efficiency of the RuH2(CO)(PPh3)3/non‐redox‐metals system. We used FTIR spectroscopy, GC–MS, NMR spectroscopy and kinetics studies to evidence that in the sluggish RuH2(CO)(PPh3)3 catalyst, bloated PPh3 ligands cause steric hindrance for the coordination of the free alkene. Alternatively, the addition of non‐redox metal ions could induce the dissociation of the PPh3 ligand to offer unoccupied coordination sites for the alkene and to form the Mg‐bridged adduct OC−Ru−H2−Mg2+ as the highly active species, which benefited the isomerization significantly through the metal hydride addition–elimination pathway. Finally, this strategy was demonstrated as an impactful approach for hydride catalysts of other transition metals such as Os.
Manganese Copper Sulfide Nanocomposites: Structure Tailoring and Photo/Electrocatalytic Hydrogen Generation
Authors: Wang Jing , Lim Yee‐Fun , Ho Ghim Wei
Published: June 2017

In this paper, we present an l‐cysteine‐mediated hydrothermal synthesis of manganese copper sulfide (MCS) nanocomposites with versatile nanostructures and demonstrate their applications in photocatalytic and electrocatalytic hydrogen generation from water splitting. Variation of the Mn/Cu molar ratios in the precursors facilely tailors the MCS nanocomposites into one‐dimensional nanowires or two‐dimensional nanosheets, which are different from the zero‐dimensional nanoparticles of pure MnS and CuS. By virtue of the well‐interfaced heterojunctions formed, the recombination of photogenerated electrons and holes is suppressed, giving rise to photocatalytic hydrogen generation behavior that is unattainable from either MnS or CuS. Moreover, the electrochemical conductivity is dramatically enhanced, rendering the MCS nanocomposites with improved electrocatalytic kinetics. This approach will contribute to an inexpensive and convenient synthetic strategy of transition‐metal‐based nanostructures for functional applications in photovoltaic, electrochemical, and catalytic fields.
Reliability of Constant Charge Method for Molecular Dynamics Simulations on EDLCs in Nanometer and Sub‐Nanometer Spaces
Authors: Yang Jinyuan , Bo Zheng , Yang Huachao , Qi Hualei , Kong Jing , Yan Jianhua , Cen Kefa
Published: June 2017

The constant charge method (CCM) and constant potential method (CPM) are two major techniques to apply electric charges on electrodes for molecular dynamics (MD) simulations on electric double‐layer capacitors (EDLCs). Compared with CCM, CPM is more realistic since the influence of electrode polarization is taken into account, although computationally more expensive. In this work, the reliability of CCM for MD simulations on EDLCs in nanometer and sub‐nanometer spaces is investigated. Particular attention is paid to the comparison of CCM and CPM for modeling EDLCs in terms of ion concentration and EDL structures in such nano/sub‐nano confined spaces, which are widely found in graphene‐based materials. The deviation for ion concentration calculated from CCM and CPM was found to be significant in both neutral and charged confined spaces (e. g., deviation ratio of 40.27 % and 11.18 % for Cl− ions in neutral and charged 9 Å space, respectively), which is different from previous observations in bulk solutions. This result could be attributed to the strong electrode polarization in nano/sub‐nano confined spaces. Although CCM and CPM yielded essentially similar EDL structures, the time evolution of electrode charge with a potential difference could be conducted only with CPM. The findings of the current work could provide useful insights for choosing appropriate methods for MD simulation on EDLCs in nano/sub‐nano confined spaces.
Complexity in Acid–Base Titrations: Multimer Formation Between Phosphoric Acids and Imines
Authors: Malm Christian , Kim Heejae , Wagner Manfred , Hunger Johannes
Published: June 2017

Solutions of Brønsted acids with bases in aprotic solvents are not only common model systems to study the fundamentals of proton transfer pathways but are also highly relevant to Brønsted acid catalysis. Despite their importance the light nature of the proton makes characterization of acid–base aggregates challenging. Here, we track such acid–base interactions over a broad range of relative compositions between diphenyl phosphoric acid and the base quinaldine in dichloromethane, by using a combination of dielectric relaxation and NMR spectroscopy. In contrast to what one would expect for an acid–base titration, we find strong deviations from quantitative proton transfer from the acid to the base. Even for an excess of the base, multimers consisting of one base and at least two acid molecules are formed, in addition to the occurrence of proton transfer from the acid to the base and simultaneous formation of ion pairs. For equimolar mixtures such multimers constitute about one third of all intermolecular aggregates. Quantitative analysis of our results shows that the acid‐base association constant is only around six times larger than that for the acid binding to an acid‐base dimer, that is, to an already protonated base. Our findings have implications for the interpretation of previous studies of reactive intermediates in organocatalysis and provide a rationale for previously observed nonlinear effects in phosphoric acid catalysis.
Vicinal Difunctionalization of Alkenes through a Multicomponent Reaction with the Insertion of Sulfur Dioxide
Authors: Zhang Jun , An Yuanyuan , Wu Jie
Published: June 2017

A four‐component reaction of aryldiazonium tetrafluoroborates, sulfur dioxide, alkenes, and hydroxylamines under mild conditions is accomplished. No catalyst or additive is needed for the vicinal difunctionalization of alkenes with the insertion of sulfur dioxide. Not only DABCO⋅(SO2)2 (DABCO=1,4‐diazabicyclo[2.2.2]octane) but also potassium metabisulfite (K2S2O5) is effective in this transformation. The multicomponent reaction proceeds efficiently at room temperature with broad substrate scope, leading to the corresponding products in good yields.
The Effect of Solution Conditions on the Driving Forces for Self‐Assembly of a Pyrene Molecule
Authors: Shi Shaowei , Liu Dapeng , Wang Xiaosong
Published: June 2017

Fe(CO){CO(CH2)5CH2‐pyrene}(Cp)(PPh3) (Fp‐pyrene) is soluble in DMSO and THF, but insoluble in water, methanol, and ethanol. The hydrophobic force drives the molecules′ assembly into vesicles in THF/water. The π–π interaction of the pyrene groups subsequently occurred within the vesicular membrane. The assembly, however, is driven by the π–π interaction in DMSO/water (water content: 40–80 vol %) into membranes, which is attributed to the relatively higher degree of de‐solvation (δ) of pyrene in DMSO. Further increase in δ (DMSO/90 vol % water) suppresses the π–π interaction and spherical particles are formed. On the other hand, the supersaturated solutions were prepared via a cycle of heating and cooling of Fp‐pyrene in methanol or ethanol. Fp‐pyrene aggregates into particles without the π–π interaction in the solutions with a lower degree of supersaturation (σ). In contrast, a higher σ induces the π–π interaction, which drives the assembly into nanotapes. The π–π interaction is a conditional effect depending on the solution conditions, which can be adjusted for the synthesis of nanostructures assembled from the same aromatic molecule.
Diagnosis of sensor precision degradation using Kullback‐Leibler divergence
Authors: Ji Hongquan , He Xiao , Zhou Donghua
Published: June 2017

For practical industrial processes, detection and isolation of a sensor precision degradation fault is of vital importance. In comparison with other sensor fault types such as complete failure and mean shift, the precision degradation fault is usually more difficult to detect and further to isolate. This paper proposes a new fault detection algorithm for sensor precision degradation using Kullback‐Leibler divergence (KLD). The KLD is employed to quantify the dissimilarity between probability densities of each reference score and the actual one within the principal component analysis (PCA) framework. Under the assumption of Gaussian‐distributed data, KLD for each score reduces to a measure of the variance difference, which is proven effective in detecting sensor precision degradation. Control limit of the KLD is established based on historical data, and online fault detection is implemented by adopting a sliding window. The fault isolation issue is also discussed, which aims to determine the faulty sensor with precision degradation. This task may be achieved by checking the PCA loading matrix and matching the fault detection result. Case studies on a synthetic numerical example and the continuous stirred tank reactor (CSTR) process are carried out to demonstrate the effectiveness of the proposed method, in comparison with conventional approaches.
Dissecting LSD1‐Dependent Neuronal Maturation in the Olfactory Epithelium
Authors: Coleman Julie H. , Lin Brian , Schwob James E.
Published: June 2017

Neurons in the olfactory epithelium (OE) each express a single dominant olfactory receptor (OR) allele from among roughly 1,000 different OR genes. While monogenic and monoallelic OR expression has been appreciated for over two decades, regulators of this process are still being described; most recently, epigenetic modifiers have been of high interest as silent OR genes are decorated with transcriptionally repressive trimethylated histone 3 lysine 9 (H3K9me3) whereas active OR genes are decorated with transcriptionally activating trimethylated histone 3 lysine 4 (H3K4me3). The lysine specific demethylase 1 (LSD1) demethylates at both of these lysine residues and has been shown to disrupt neuronal maturation and OR expression in the developing embryonic OE. Despite the growing literature on LSD1 expression in the OE, a complete characterization of the timing of LSD1 expression relative to neuronal maturation and of the function of LSD1 in the adult OE have yet to be reported. To fill this gap, the present study determined that LSD1 (1) is expressed in early dividing cells before OR expression and neuronal maturation and decreases at the time of OR stabilization; (2) colocalizes with the repressor CoREST (also known as RCOR1) and histone deacetylase 2 in these early dividing cells; and (3) is required for neuronal maturation during a distinct time window between activating reserve stem cells (horizontal basal cells) and Neurogenin1 (+) immediate neuronal precursors. Thus, this study clarifies the role of LSD1 in olfactory neuronal maturation.
Safety, Tolerability, and Pharmacokinetics of Single and Multiple Oral Doses of an Omega‐3‐Carboxylic Acid Formulation in Healthy Male Japanese Subjects: A Phase 1 Single‐Blind, Randomized, Placebo‐Controlled Trial
Authors: Noda Yoshinori , Nilsson Catarina , Shimada Hitoshi , Kim Hyosung , Lundström Torbjörn , Yajima Toshitaka
Published: June 2017

OM3‐CA (omega‐3‐carboxylic acids) is a complex mixture of omega‐3 carboxylic acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which is approved in the United States for the treatment of hypertriglyceridemia. As part of its clinical development in Japan, we performed a phase 1 study to investigate the safety, tolerability, and pharmacokinetics after single and multiple doses of OM3‐CA in healthy male Japanese subjects. Eighteen Japanese subjects were allocated to receive 2 or 4 g/day OM3‐CA, or placebo (n = 6 per group). In addition, 6 white subjects received 4 g/day OM3‐CA. The primary objective was to determine the safety and tolerability of OM3‐CA. Plasma concentrations of EPA and DHA were adjusted for baseline values for pharmacokinetic analysis. Overall, OM3‐CA was well tolerated in healthy Japanese subjects. Two Japanese subjects in each group and 5 white subjects experienced adverse events (AEs). Alanine aminotransferase increase was the most common AE in Japanese subjects, also seen with placebo, and diarrhea was the most common AE in white subjects. The maximum plasma concentrations of EPA and DHA were observed 5–6 hours postdose. The pharmacokinetic profiles of EPA and DHA after administration of OM3‐CA were comparable between Japanese and white subjects.
In Silico Design of DNP Polarizing Agents: Can Current Dinitroxides Be Improved?
Authors: Perras Frédéric A. , Sadow Aaron , Pruski Marek
Published: June 2017

Numerical calculations of enhancement factors offered by dynamic nuclear polarization in solids under magic angle spinning (DNP‐MAS) were performed to determine the optimal EPR parameters for a dinitroxide polarizing agent. We found that the DNP performance of a biradical is more tolerant to the relative orientation of the two nitroxide moieties than previously thought. Generally, any condition in which the gyy tensor components of both radicals are perpendicular to one another is expected to have near‐optimal DNP performance. Our results highlight the important role of the exchange coupling, which can lessen the sensitivity of DNP performance to the inter‐radical distance, but also lead to lower enhancements when the number of atoms in the linker becomes less than three. Lastly, the calculations showed that the electron T1e value should be near 500 μs to yield optimal performance. Importantly, the newest polarizing agents already feature all of the qualities of the optimal polarizing agent, leaving little room for further improvement. Further research into DNP polarizing agents should then target non‐nitroxide radicals, as well as improvements in sample formulations to advance high‐temperature DNP and limit quenching and reactivity.
On the Importance of Nonbonding Donor–Acceptor Interactions Involving PO2.Radicals: An ab Initio Study
Authors: Bauzá Antonio , Frontera Antonio
Published: June 2017

In this study, several σ‐type and π‐hole bonding complexes between PO2.radicals and electron‐rich entities have been optimized at the RI‐MP2/aug‐cc‐pVQZ level of theory. We have used Cl−, Br−, I−anions, and ethene, ethyne, HCN, HF, and H2O as Lewis bases. In addition, we have performed natural bond orbital (NBO) and Mulliken spin density analyses, highlighting the donor–acceptor nature of the interaction. Moreover, an interesting retro‐donation from the single electron lone pair of the PO2.radical to the Lewis base also contributes to the stabilization of the complexes studied herein. Finally, the Bader's atoms‐in‐molecules (AIM) analysis of several complexes has been performed to further characterize the interactions discussed herein.
A direct conversion transmitter with digital‐assisted DC offset and I/Q phase calibration
Authors: Chang Chia‐Hung , Chen Wei‐Hsien , Gong Cihun‐Siyong Alex , Hu Wei‐Wen
Published: June 2017

A direct conversion transmitter with auto‐calibration mechanism is presented in this paper. Both the carrier leakage and in‐phase/quadrature (I/Q) phase imbalance are compensated by a proposed calibration algorithm to improve transmitter's single‐sideband performance. The digital‐assisted correction circuits are implemented in a calibration feedback path to reduce the mismatches and variations, which in turn achieves properties of high linearity, high sideband, and carrier suppression ratio. The measured single‐sideband performance with calibration applied to the transmitter demonstrates an over 40 and 50‐dBc rejection on sideband and carrier signals at the desired frequency band, respectively. For linearity performance, the measured output 1‐dB compression point (OP1dB) is 9.1 dBm, while the highest voltage gain is from 4.3 to 6.2 dB. Additionally, the error vector magnitude (EVM) of −37.082 dB (< 1.4%) can be achieved under an orthogonal frequency division multiple access (OFDMA) 64 QAM‐3/4 modulated signal test. The transmitter consumes 112.7 mA under supply voltage of 3.3 V using the TSMC SiGe BiCMOS technology. Copyright © 2017 John Wiley & Sons, Ltd.
Urinary tract washing specimens containing atypical urothelial tissue fragments are significantly associated with urothelial neoplasia
Authors: Zhang M. Lisa , Zhou Amy G. , Rosenthal Dorothy L. , VandenBussche Christopher J.
Published: June 2017

Background

We previously found that the presence of atypical urothelial tissue fragments (AUTF) was associated with an increased risk of high‐grade urothelial carcinoma (HGUC) but not low‐grade urothelial neoplasia (LGUN) in voided urine (VU) specimens. However, we subsequently found that patients with LGUN were more likely to have cytologic atypia in urinary washing (UW) specimens, suggesting that cytologic atypia found in UW specimens might be associated with both LGUN and HGUC. In this study, we retrospectively examined UW specimens containing AUTF to determine whether they were associated with HGUC, LGUN, or both HGUC and LGUN.

Methods

1173 UW specimens and any follow up biopsies were identified over a 10‐year period and the presence of AUTF was recorded based on the original clinical diagnosis.

Results

The presence of AUTF in UW specimens was significantly associated with high‐risk indeterminate diagnosis or definitive diagnosis of HGUC (P < .001). In addition, AUTF specimens were significantly associated with a neoplastic diagnosis of low‐grade urothelial carcinoma (LGUC) or HGUC on subsequent biopsies when compared to specimens lacking AUTF (P = .047). The overall rate of CIS/HGUC in specimens with AUTF was 33.0 vs. 13.5% for specimens without AUTF (P = .051).

Conclusions

Urothelial tissue fragments (UTF) found in UW specimens should be examined for the presence of cytomorphological atypia, as the presence of AUTF almost triples the risk of HGUC. As opposed to what has been found in VU specimens, AUTF in UW specimens is also associated with an increased risk of LGUN.