bluuebunny/crossref_metadata_2025 huggingface dataset:
Singulett‐Sauerstoff in der aprotischen Natrium‐O2‐Batterie
Authors: Schafzahl Lukas , Mahne Nika , Schafzahl Bettina , Wilkening Martin , Slugovc Christian , Borisov Sergey M. , Freunberger Stefan A.
Published: October 2017

Aprotische Natrium‐O2‐Batterien basieren auf der reversiblen Bildung und Auflösung von Natriumsuperoxid (NaO2) während des Zellbetriebs. Nebenreaktionen des Elektrolyten und der Elektrode mit dem stark nukleophilen und basischen NaO2 führen zu mangelhafter Zyklenstabilität. Seine Reaktivität allein kann die Nebenreaktionen und schlechte Reversibilität jedoch nicht schlüssig erklären. Hier wird gezeigt, dass Singulett‐Sauerstoff (1O2) in allen Phasen des Betriebs entsteht und eine Hauptursache für Nebenreaktionen ist. 1O2 wurde in situ und ex situ mit einem 1O2‐Fänger detektiert, der schnell und selektiv ein Addukt mit 1O2 bildet. Mechanistisch betrachtet entsteht 1O2 entweder durch protonenunterstützte Disproportionierung von Superoxid während des Entladens, Lagerns und Ladens unter ca. 3.3 V oder durch direkte elektrochemische 1O2‐Entwicklung über ca. 3.3 V. Spuren von Wasser ermöglichen hohe Kapazitäten, beschleunigen aber auch Nebenreaktionen. Daher muss das hochreaktive 1O2 unbedingt kontrolliert werden, um die Zelle reversibel zu betreiben.
A Lewis Base Catalysis Approach for the Photoredox Activation of Boronic Acids and Esters
Authors: Lima Fabio , Sharma Upendra K. , Grunenberg Lars , Saha Debasmita , Johannsen Sandra , Sedelmeier Joerg , Van der Eycken Erik V. , Ley Steven V.
Published: October 2017

We report herein the use of a dual catalytic system comprising a Lewis base catalyst such as quinuclidin‐3‐ol or 4‐dimethylaminopyridine and a photoredox catalyst to generate carbon radicals from either boronic acids or esters. This system enabled a wide range of alkyl boronic esters and aryl or alkyl boronic acids to react with electron‐deficient olefins via radical addition to efficiently form C−C coupled products in a redox‐neutral fashion. The Lewis base catalyst was shown to form a redox‐active complex with either the boronic esters or the trimeric form of the boronic acids (boroxines) in solution.
Lanthanide‐Based T2ex and CEST Complexes Provide Insights into the Design of pH Sensitive MRI Agents
Authors: Zhang Lei , Martins André F. , Zhao Piyu , Wu Yunkou , Tircsó Gyula , Sherry A. Dean
Published: October 2017

The CEST and T1/T2 relaxation properties of a series of Eu3+ and Dy3+ DOTA‐tetraamide complexes with four appended primary amine groups are measured as a function of pH. The CEST signals in the Eu3+ complexes show a strong CEST signal after the pH was reduced from 8 to 5. The opposite trend was observed for the Dy3+ complexes where the r2ex of bulk water protons increased dramatically from ca. 1.5 mm−1 s−1 to 13 mm−1 s−1 between pH 5 and 9 while r1 remained unchanged. A fit of the CEST data (Eu3+ complexes) to Bloch theory and the T2ex data (Dy3+ complexes) to Swift–Connick theory provided the proton‐exchange rates as a function of pH. These data showed that the four amine groups contribute significantly to proton‐catalyzed exchange of the Ln3+‐bound water protons even though their pKa’s are much higher than the observed CEST or T2ex effects. This demonstrated the utility of using appended acidic/basic groups to catalyze prototropic exchange for imaging tissue pH by MRI.
A Hydrogen‐Bonded Hexagonal Buckybowl Framework
Authors: Hisaki Ichiro , Toda Hideaki , Sato Hiroyasu , Tohnai Norimitsu , Sakurai Hidehiro
Published: October 2017

A hydrogen‐bonded two‐dimensionally networked buckybowl architecture is presented. Two types of hexagonal network (HexNet) structures (CPSM‐1 and CPSM‐2) have been achieved based on a sumanene derivative (CPSM) possessing 4,4′‐dicarboxy‐o‐terphenyl groups in the periphery. CPSM‐1 has a waved HexNet structure with an alternate alignment of upward and downward bowls. CPSM‐2 has a bilayered HexNet structure composed of hamburger‐shaped dimers of the bowls. This demonstrates that non‐planar π‐systems can be networked two‐dimensionally by an appropriate supramolecular synthon to achieve structurally well‐defined unique bumpy π‐sheets. Furthermore, we revealed that CPSM‐2 undergoes anisotropic shrinking along the c axis by 11 % under high pressure conditions (970 MPa). The shrinkage is brought about by offset sliding between bumpy π‐surfaces of the bilayered HexNet sheets.
Precise Assembly of Particles for Zigzag or Linear Patterns
Authors: Guo Dan , Li Chang , Wang Yang , Li Yanan , Song Yanlin
Published: October 2017

Precise control of particles assembly has tremendous potential for fabricating intricate structures and functional materials. However, it is still a challenge to achieve one‐dimensional assembly with precisely controlled morphology. An effective strategy is reported to precisely assemble particles into well‐defined patterns by liquid confinement through controlling the viscosity of the assembly system. It is found that high viscosity of the system impedes particles rearrangement and facilitates the generation of zigzag or twined zigzag assembly structures, while low viscosity of the system allows particles to rearrange into linear or zipper structures driven by lowering the surface deformation of the liquid. As a result, precise control of different assembly patterns can be achieved through tuning the viscosity of solvent and size confinement ratios. This facile approach shows generality for particles assembly of different sizes and materials.
Singlet Oxygen during Cycling of the Aprotic Sodium–O2 Battery
Authors: Schafzahl Lukas , Mahne Nika , Schafzahl Bettina , Wilkening Martin , Slugovc Christian , Borisov Sergey M. , Freunberger Stefan A.
Published: October 2017

Aprotic sodium–O2 batteries require the reversible formation/dissolution of sodium superoxide (NaO2) on cycling. Poor cycle life has been associated with parasitic chemistry caused by the reactivity of electrolyte and electrode with NaO2, a strong nucleophile and base. Its reactivity can, however, not consistently explain the side reactions and irreversibility. Herein we show that singlet oxygen (1O2) forms at all stages of cycling and that it is a main driver for parasitic chemistry. It was detected in‐ and ex‐situ via a 1O2 trap that selectively and rapidly forms a stable adduct with 1O2. The 1O2 formation mechanism involves proton‐mediated superoxide disproportionation on discharge, rest, and charge below ca. 3.3 V, and direct electrochemical 1O2 evolution above ca. 3.3 V. Trace water, which is needed for high capacities also drives parasitic chemistry. Controlling the highly reactive singlet oxygen is thus crucial for achieving highly reversible cell operation.
Development of antifouling poly(vinyl chloride) blend membranes by atom transfer radical polymerization
Authors: Fang Li‐Feng , Matsuyama Hideto , Zhu Bao‐Ku , Zhao Shuaifei
Published: October 2017

In this study, antifouling poly(vinyl chloride) (PVC) blend membranes were prepared by blending the PVC based amphiphilic copolymer PVC‐g‐poly(hydroxyethyl methacrylate) (PVC‐g‐PHEMA), synthesized by atom transfer radical polymerization (ATRP), into the hydrophobic PVC matrix via the nonsolvent‐induced phase separation method. The in situ ATRP reaction solutions were also used as the blend additives to improve membrane performance. Attenuated total reflectance–Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy indicated that the blend membranes based on the two blend routes exhibited similar surface chemical compositions. The membrane morphology and surface wettability were determined by scanning electronic microscopy and water contact angle measurement, respectively. The blend membranes showed improved water permeability, comparable rejections and enhanced antifouling properties compared with the pure PVC membrane. The PVC blend membranes also had excellent long‐term stability in terms of chemical compositions and fouling resistance. The results demonstrated that ATRP was a promising technique to synthesize amphiphilic copolymer and prepare stable blend antifouling membranes. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45832.
Pervaporation of toluene and iso‐octane through poly(vinyl alcohol)/graphene oxide nanoplate mixed matrix membranes: Comparison of crosslinked and noncrosslinked membranes
Authors: Khazaei Ali , Mohebbi Vahid , Behbahani Reza M. , Ramazani S.A. Ahmad
Published: October 2017

Removal of aromatic compounds from fuel is an essential requirement in new environmental policies. In the present study, poly(vinyl alcohol)/graphene oxide (GO) mixed matrix membranes were prepared and applied to the separation of toluene from iso‐octane by pervaporation, considering the similarity and interaction between graphene and aromatics. The effects of crosslinking and GO content on separation efficiency have been investigated in detail. Owing to the high affinity of GO with toluene through s and π bonds, the selectivity of the membranes was increased by incorporating a low amount of GO. The results also indicated that noncrosslinked membranes have higher selectivity and permeation flux due to higher crystallinity and also have lower mechanical properties. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45853.
Preparation of block copolymers via metal‐free visible‐light‐induced ATRP for the detection of lead ions
Authors: Sun Yue , Li Juan , Zhao Mengyuan , Liu Yutong , Zhang Jiameng , Lv Chengwei
Published: October 2017

Polyacrylamide‐b‐poly(methacrylic acid) was prepared on the surface of Au electrode (Au/PAM/PMAA) for Pb2+ ion electrochemical sensing via metal‐free visible‐light‐induced atom transfer radical polymerization, which was very simple, convenient, and environmentally friendly. Au/PAM/PMAA was carefully examined by cyclic voltammetry, electrochemical impedance spectroscopy, and X‐ray photoelectron spectroscopy. Further, Au/PAM/PMAA was successfully used for the determination of Pb2+ ion by differential pulse anodic stripping voltammetry. Under the optimal conditions, a linear response from 1.0 × 10−11 to 1.0 × 10−4 mol/L with detection limit of 2.5 × 10−12 mol/L (S/N = 3) was achieved from the results of experiments. Comparing with similar Pb2+ sensors, the broader linear range and lower detection limit suggested the promising prospect of Au/PAM/PMAA. In a word, the work of this article had an important significance for the polymer‐modified electrodes and the sensitive detection of Pb2+. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45863.
Morpho‐demographic traits of two maërl‐forming algae in beds with different depths and fishing histories
Authors: Cabanellas‐Reboredo Miguel , Mallol Sandra , Barberá Carmen , Vergés Alba , Díaz David , Goñi Raquel
Published: October 2017

Maërl is a benthic community composed of accumulations of coralline red algae with an essential eco‐biological role in marine ecosystems.

This low‐resilience community has acquired a high conservation status as many anthropogenic impacts threaten this globally distributed ecosystem. Some of the potentially more important but less studied impacts are those caused by fishing activities due to the lack of proper controls.

This study investigates the potential fishing impacts and depth‐related differences on the rhodolith morpho‐demographic traits of two maërl‐forming algae, Lithothamnion corallioides and Spongites fruticulosus, with distinct morphologies (ramified vs nucleated).

Rhodolith size and shape (roundness and solidity) indicators were assessed in maërl beds protected from fishing inside a large 25‐year old no‐take MPA, in a contiguous 6‐year no‐take zone, and in adjacent fished beds.

Rhodoliths of both species were bigger, rounder (spherical) and more solid (structurally less complex) in shallow than in deep beds of the long‐term protected area, which was probably a result of a more active hydrodynamic regime and higher irradiance in shallow beds.

Fishing effects manifested differently depending on the morphological properties of rhodoliths, which resulted in a decrease in size and complexity in L. corallioides and roundness in S. fruticulosus.

Such fishing impacts were significant only inside the short‐term 6‐year protected area. The most plausible cause of this unexpected observation is the highly localized trammel‐net fishing effort with long soak‐times along the boundary of the contiguous 25‐year MPA, where before closure, fishing effort was concentrated in expectation of greater catches from spillover (i.e. fishing the line).

This is the first study to document the impacts of fishing the line on structural species and indicates that boundaries of successful MPAs could be zones of maximum disturbance, a fact that should be taken into account in management conservation decisions.
Biosensors: Classifications, medical applications, and future prospective
Authors: Alhadrami Hani A.
Published: October 2017

Biosensors are devices that combine a biological material with a suitable platform for detection of pathogenic organisms, carcinogenic, mutagenic, and/or toxic chemicals or for reporting a biological effect. In recent years, an enormous number of different types of biosensors have been constructed and developed for several medical applications. The reason for that was primarily due to the numerous advantages and applications that can be offered by biosensors. This review article has been started with demonstrating the power of biosensor technologies versus analytical and conventional techniques. Subsequently, more emphasis has been added on the classification and the role of biosensors in several medical applications such as detection and monitoring of carcinogenic and mutagenic chemicals, reporting of endocrine disrupting compounds, and detection of pathogenic organisms. The most common reporter genes used in biosensors engineering and construction have also been summarized. Prospective strategies and recommendations for the future construction of biosensors have been highlighted.
Effects of extremely low frequency magnetic field on the development of tolerance to the analgesic effect of morphine in rats
Authors: Jadidi Majid , Khatami Mahfouzeh Sadat , Mohammad‐pour Fatemeh , Bandavi Afsaneh , Rashidy‐pour Ali , Vafaei Abbas Ali , Taherian Abbas Ali , Miladi‐Gorji Hossein
Published: October 2017

This study examined the effects of low frequency magnetic field (MF) on tolerance to analgesic effect of morphine in rats. Rats were made tolerant to morphine by injecting morphine (10 mg/kg, s) once daily for 8 consecutive days. Rats were simultaneously exposed to an MF (50 Hz at 1, 50, and 100 μT for 30 min) before, immediately, or 30 min after injection of morphine, and also exposed to a 0.5, 6, 12, and 30 Hz at 100 μT for 30 min before injection of morphine. The percentage of maximum possible effect of morphine (% MPE) was measured on the 1st, 4th, and 8th days by hot plate test. We observed that MF radiation (50 Hz at 1 µT and 30 Hz at 100 µT) immediately before and MF radiation (50 Hz at 100 µT) after morphine injection prevented the development of morphine tolerance compared to control. Also, we found that exposure to MF (50 Hz at 1, 50, and 100 µT) 30 min after injection of morphine failed to maintain the analgesic effect of morphine. Our results showed that exposure to low frequency electromagnetic field (30 and 50 Hz) immediately before or after the injection of morphine may be a potential method for treating the development of morphine tolerance in rats. Bioelectromagnetics. 38:618–625, 2017. © 2017 Wiley Periodicals, Inc.
Association between weight gain during adjuvant chemotherapy for early‐stage breast cancer and survival outcomes
Authors: Schvartsman Gustavo , Gutierrez‐Barrera Angelica M. , Song Juhee , Ueno Naoto T. , Peterson Susan K. , Arun Banu
Published: October 2017

Obese and overweight women have an increased risk of breast cancer and worse outcomes at the time of diagnosis. Women tend to gain weight after breast cancer diagnosis and during chemotherapy for early‐stage disease, which may in turn increase risk for worse outcomes. We examined if weight gained during adjuvant chemotherapy was associated with worse survival outcomes. We queried our database for data on patients who received adjuvant third‐generation chemotherapy for early‐stage breast cancer. Univariate and multivariate analyses by Cox regression were performed for survival outcomes across three categories according to BMI variation from start to end of chemotherapy: >0.5 kg/m2 loss or gain and stable BMI (±0.5 kg/m2). We included 1998 patients in this study. Women over 50 years old and postmenopausal were more likely to lose weight during adjuvant chemotherapy, whereas women under 30 years old gained more weight (P < 0.001). At 1 year postchemotherapy, patients tended to return to their original weight (ρ = −0.3, P < 0.001). On multivariate analysis, BMI increase of >0.5 kg/m2 compared to maintaining BMI was marginally associated with increased locoregional recurrence risk (HR: 2.53; 95% CI, 1.18–5.45; P = 0.017), adjusting for grade, stage, and radiation delivery. Weight variation during adjuvant chemotherapy for early‐stage breast cancer may occur as both weight gain and weight loss in a balanced manner. Furthermore, this variation seems to be transient in nature and does not appear to significantly influence recurrence rates and overall survival.
Targeting MTA1/HIF‐1α signaling by pterostilbene in combination with histone deacetylase inhibitor attenuates prostate cancer progression
Authors: Butt Nasir A. , Kumar Avinash , Dhar Swati , Rimando Agnes M. , Akhtar Israh , Hancock John C. , Lage Janice M. , Pound Charles R. , Lewin Jack R. , Gomez Christian R. , Levenson Anait S.
Published: October 2017

The metastasis‐associated protein 1(MTA1)/histone deacetylase (HDAC) unit is a cancer progression‐related epigenetic regulator, which is overexpressed in hormone‐refractory and metastatic prostate cancer (PCa). In our previous studies, we found a significantly increased MTA1 expression in a prostate‐specific Pten‐null mouse model. We also demonstrated that stilbenes, namely resveratrol and pterostilbene (Pter), affect MTA1/HDAC signaling, including deacetylation of tumor suppressors p53 and PTEN. In this study, we examined whether inhibition of MTA1/HDAC using combination of Pter and a clinically approved HDAC inhibitor, SAHA (suberoylanilide hydroxamic acid, vorinostat), which also downregulates MTA1, could block prostate tumor progression in vivo. We generated and utilized a luciferase reporter in a prostate‐specific Pten‐null mouse model (Pb‐Cre+; Ptenf/f; Rosa26Luc/+) to evaluate the anticancer efficacy of Pter/SAHA combinatorial approach. Our data showed that Pter sensitized tumor cells to SAHA treatment resulting in inhibiting tumor growth and additional decline of tumor progression. These effects were dependent on the reduction of MTA1‐associated proangiogenic factors HIF‐1α, VEGF, and IL‐1β leading to decreased angiogenesis. In addition, treatment of PCa cell lines in vitro with combined Pter and low dose SAHA resulted in more potent inhibition of MTA1/HIF‐1α than by high dose SAHA alone. Our study provides preclinical evidence that Pter/SAHA combination treatment inhibits MTA1/HIF‐1α tumor‐promoting signaling in PCa. The beneficial outcome of combinatorial strategy using a natural agent and an approved drug for higher efficacy and less toxicity supports further development of MTA1‐targeted therapies in PCa.
Orthogonal Expression of an Artificial Metalloenzyme for Abiotic Catalysis
Authors: Reynolds Evan W. , Schwochert Timothy D. , McHenry Matthew W. , Watters John W. , Brustad Eric M.
Published: October 2017

A cytochrome P450 was engineered to selectively incorporate Ir(Me)‐deuteroporphyrin IX (Ir(Me)‐DPIX), in lieu of heme, in bacterial cells. Cofactor selectivity was altered by introducing mutations within the heme‐binding pocket to discriminate the deuteroporphyrin macrocycle, in combination with mutations to the P450 axial cysteine to accommodate a pendant methyl group on the Ir(Me) center. This artificial metalloenzyme was investigated for activity in non‐native metallocarbenoid‐mediated olefin cyclopropanation reactions and showed enhanced activity for aliphatic and electron‐deficient olefins when compared to the native heme enzyme. This work provides a general strategy to augment the chemical functionality of heme enzymes in cells with application towards abiotic catalysis.
Reactivity of Ir–NSiN Complexes: Ir‐Catalyzed Dehydrogenative Silylation of Carboxylic Acids
Authors: Julián Alejandro , Garcés Karin , Lalrempuia Ralte , Jaseer E. A. , García‐Orduña Pilar , Fernández‐Alvarez Francisco J. , Lahoz Fernando J. , Oro Luis A.
Published: October 2017

This work describes the results from the studies on the potential of [Ir(μ‐Cl)(cod)]2 (cod=1,5‐cyclooctadiene) as metallic precursor for the preparation of Ir(NSiN) complexes (NSiN=fac‐bis‐(pyridine‐2‐yloxy)methylsilyl). The reaction of [Ir(μ‐Cl)(cod)]2 with bis‐(pyridine‐2‐yloxy)methylsilane enabled the synthesis of [Ir(H)(Cl)(NSiN)(η2‐cod)] with an uncommon η2‐coordination mode for the cod ligand. The application of Ir–NSiN species as catalysts precursors for the dehydrogenative silylation of carboxylic acids was also explored. The outcomes from these catalytic studies revealed a clear influence of the ancillary ligand on the catalytic activity of Ir–NSiN species. Thus, whereas [Ir(H)(CF3SO3)(NSiN)(coe)] shows poor catalytic activity, the related complex [Ir(H)(CF3CO2)(NSiN)(coe)] with a trifluoroacetate ligand was demonstrated to be a highly active catalyst precursor.
N‐Methyl Inversion and Accurate Equilibrium Structures in Alkaloids: Pseudopelletierine
Authors: Vallejo‐López Montserrat , Écija Patricia , Vogt Natalja , Demaison Jean , Lesarri Alberto , Basterretxea Francisco J. , Cocinero Emilio J.
Published: October 2017

Invited for the cover of this issue are the groups of Natalja Vogt at the University of Ulm, Alberto Lesarri at the University of Valladolid and Emilio J. Cocinero at the University of Pais Vasco. The image depicts the family tree of tropane alkaloids, to which pseudopelletierine belongs, and their occurrence in nature. Read the full text of the article at 10.1002/chem.201702232.
Cross‐Linking of Cellulosic Materials: Manufacturing Strategies and Analytical Approaches
Authors: Tolk Jakob , Reiche Annette
Published: October 2017

Cellulose ist ein einzigartiges Polymer, das viele Kunststoffe in Widerstand, mechanischer Festigkeit und anderen Schlüsseleigenschaften übertrifft. Trotzdem ist es oft notwendig, ihre Eigenschaften optimal auf die Anforderungen des jeweiligen Einsatzgebietes anzupassen. In vielen Fällen werden Produkte auf Cellulosebasis chemisch vernetzt. Dieser Beitrag gibt einen kritischen Überblick über existierende Vernetzungsverfahren aus unterschiedlichsten Bereichen der Celluloseverarbeitung und geht auf Ansätze zur Charakterisierung vernetzter Cellulose ein.
Rationalizing Promiscuity Cliffs
Authors: Dimova Dilyana , Bajorath Jürgen
Published: October 2017

Compound promiscuity can be viewed in different ways. We distinguish “bad” promiscuity resulting from chemical liabilities, nonspecific binding, or assay artifacts, from “good” promiscuity representing true multitarget activities. Investigating multitarget activities of small molecules is scientifically stimulating and therapeutically relevant. To better understand the molecular basis of multitarget activities, structure‐promiscuity relationships (SPRs) are explored. For this purpose, “promiscuity cliffs” (PCs) have been introduced, which can be rationalized as an extension of the activity cliff (AC) concept. A PC is defined as a pair of structural analogues that are active against different numbers of targets (given a difference threshold). As discussed herein PCs frequently capture surprising SPRs and encode many experimentally testable hypotheses.
Recovery from the anatomical effects of long‐term monocular deprivation in cat lateral geniculate nucleus
Authors: Duffy Kevin R. , Fong Ming‐fai , Mitchell Donald E. , Bear Mark F.
Published: October 2017

Monocular deprivation (MD) imposed early in postnatal life elicits profound structural and functional abnormalities throughout the primary visual pathway. The ability of MD to modify neurons within the visual system is restricted to a so‐called critical period that, for cats, peaks at about one postnatal month and declines thereafter so that by about 3 months of age MD has little effect. Recovery from the consequences of MD likewise adheres to a critical period that ends by about 3 months of age, after which the effects of deprivation are thought to be permanent and without capacity for reversal. The attenuation of plasticity beyond early development is a formidable obstacle for conventional therapies to stimulate recovery from protracted visual deprivation. In the current study we examined the efficacy of dark exposure and retinal inactivation with tetrodotoxin to promote anatomical recovery in the dorsal lateral geniculate nuclues (dLGN) from long‐term MD started at the peak of the critical period. Whereas 10 days of dark exposure or binocular retinal inactivation were not better at promoting recovery than conventional treatment with reverse occlusion, inactivation of only the non‐deprived (fellow) eye for 10 days produced a complete restoration of neuron soma size, and also reversed the significant loss of neurofilament protein within originally deprived dLGN layers. These results reveal a capacity for neural plasticity and recovery that is larger than anything previously observed following protracted MD in cat, and they highlight a possibility for alternative therapies applied at ages thought to be recalcitrant to recovery.
Chiral Amplification by L‐Cysteine‐Capped Gold Nanoparticles in Lyotropic Chromonic Liquid Crystals
Authors: Bergquist Leah , Hegmann Torsten
Published: October 2017

Transfer of chirality from an adsorbed molecule to a metal nanoparticle surface, and from the resulting chiral nanoparticle to its surroundings, depends on numerous factors – structure of the adsorbed molecule, its size and shape, and its interactions with its specific environment – but is often difficult to understand and even more difficult to measure, visualize, and quantify. This severely limits the potential of chiral nanoparticles in a range of emerging applications as optical metamaterials, enantioselective catalysts, or chiral discriminators for biomacromolecules. We examine if chirality at the nanoscale (i. e. in gold nanoparticles capped with chiral ligand molecules) is uniquely able to generate more intense responses than their organic chiral counterparts in soft condensed matter utilizing lyotropic chromonic liquid crystals (LCLCs) forming the nematic phase. As a powerful manifestation of nanoscale chiral amplification, we show that L‐cysteine capped gold nanoparticles induce a tighter chiral twist within, and similar among, stacks of nematic LCLCs with several orders of magnitude fewer chiral L‐cysteine ligands in comparison to the free molecular L‐amino acid.
Workload prediction and balance for distributed reachability processing for large‐scale attribute graphs
Authors: Ho Li‐Yung , Wu Jan‐Jan , Liu Pangfeng
Published: October 2017

Reachability query with label constraint in an attribute graph is one of the most fundamental and important operations in semantic network analysis. However, ever‐growing graph size has resulted in intractable reachability problems on single machines.

This work aims to devise efficient solutions for the reachability with label constraint problem in an attribute graph in a distributed environment. We focus on two issues in distributed processing—data locality and workload balancing—since data locality reduces communication overhead and workload balancing improves the efficiency of cluster use. We propose three novel techniques to address the two issues: (1) a partition replication method that improves data locality while conserving community property, (2) a workload‐prediction method that accurately predicts machine workloads for a given quer, and (3) a workload balancing method that uses these predictions to shift partial workloads among machines to produce a balanced workload. Experimental results suggest that these techniques significantly improve performance and reduce total execution time by 40%.
Band‐Gap Engineering of Graphene Heterostructures by Substitutional Doping with B3N3
Authors: Sawahata Hisaki , Maruyama Mina , Cuong Nguyen Thanh , Omachi Haruka , Shinohara Hisanori , Okada Susumu
Published: October 2017

We investigated the energetics and electronic structure of B3N3‐doped graphene employing density functional theory calculations with the generalized gradient approximation. Our calculations reveal that all of the B3N3‐doped graphene structures are semiconducting, irrespective of the periodicity of the B3N3 embedded into the graphene network. This is in contrast to graphene nanomeshes, which are either semiconductors or metals depending on the mesh arrangement. In B3N3‐doped graphene, the effective masses for both electrons and holes are small. The band gap in the B3N3‐doped graphene networks and the total energy of the B3N3‐doped graphene are inversely proportional to the B3N3 spacing. Furthermore, both properties depend on whether or not the graphene region possesses a Clar structure. In particular, the sheets with a Clar structure exhibit a wider band gap and a slightly lower total energy than those without a Clar structure.
Measuring lip force by oral screens Part 2: The importance of screen design, instruction and suction
Authors: Wertsén Madeleine , Stenberg Manne
Published: October 2017

The aim of this study was to find a reliable method for measuring lip force and to find the most important factors that influence the measurements in terms of magnitude and variability. The hypothesis tested was that suction is involved and thus the instruction and the design of the oral screen are of importance when measuring lip force. This is a methodological study in a healthy population. This study was conducted in a general community. The designs of the screens were soft and hard prefabricated screens and 2 semi‐individually made with a tube allowing air to pass. The screens and the instructions squeeze or suck were tested on 29 healthy adults, one at a time and on 4 occasions. The test order of the screens was randomized. Data were collected during 4 consecutive days, and the procedure was repeated after 1 month. The participants were 29 healthy adult volunteers. The instruction was an important mean to distinguish between squeezing and sucking. The design of the screen affected the lip force so that it increases in relation to the projected area of the screen. A screen design with a tube allowing air to pass made it possible to avoid suction when squeezing. By measuring with and without allowing air to pass, it was possible to distinguish between suction related and not suction related lip force. The additional screen pressure when sucking was related to the ability to produce a negative intraoral pressure. In conclusion lip force increases in relation to the projected area of the screen, sucking generally increases the measured lip force and the additional screen pressure when sucking is related to the ability to produce a negative intraoral pressure.
Intermediate and nonclassical monocytes show heterogeneity in patients with different types of acute coronary syndrome
Authors: Leers Math P. G. , Stockem Chantal , Ackermans Dianne , Loeffen Rinske , ten Cate Hugo , Kragten Johannes A. , Jie Kon‐Siong G.
Published: October 2017

This study was performed to gain further insight in the heterogeneity of monocytes in the different categories of acute coronary syndrome (ACS), especially between patients with unstable angina pectoris, ST‐elevation myocardial infarction (STEMI), and non‐ST‐elevation myocardial infarction (NSTEMI). For this purpose, blood samples were collected in the acute phase from patients presenting with an ACS. These samples were examined with multiparameter flow cytometry to identify the different monocyte subsets and to analyze the expression of monocyte‐associated molecules. Leukocytes, as well as an absolute number of monocytes, showed a clear and significant increase in patients with STEMI. This increase was seen in all subtypes of monocytes. The classical monocytes (CD14++CD16–) of patients with an NSTEMI had a significantly increased CD11b expression when compared to the control group, while these cells showed a decreased expression pattern in STEMI patients. This increased CD11b‐expression was also seen in the intermediate monocytes of NSTEMI, while it was almost completely downregulated on the intermediate monocytes of STEMI. Finally, CX3CR1, which is almost exclusively expressed on intermediate and nonclassical monocytes, showed a significant decrease in expression in patients with STEMI. In conclusion, intermediate and nonclassical monocytes have a different immunophenotypic pattern in patients with STEMI versus NSTEMI. These differences reflect the pro‐inflammatory state of the monocytes in NSTEMI and can be used as target molecules for novel therapeutic strategies to diminish the migration of proinflammatory monocytes into the myocardial tissue. © 2017 International Society for Advancement of Cytometry
hace1 Influences zebrafish cardiac development via ROS‐dependent mechanisms
Authors: Razaghi Babak , Steele Shelby L. , Prykhozhij Sergey V. , Stoyek Matthew R. , Hill Jessica A. , Cooper Matthew D. , McDonald Lindsay , Lin William , Daugaard Mads , Crapoulet Nicolas , Chacko Simi , Lewis Stephen M. , Scott Ian C. , Sorensen Poul H. B. , Berman Jason N.
Published: October 2017

Background: In this study, we reveal a previously undescribed role of the HACE1 (HECT domain and Ankyrin repeat Containing E3 ubiquitin‐protein ligase 1) tumor suppressor protein in normal vertebrate heart development using the zebrafish (Danio rerio) model. We examined the link between the cardiac phenotypes associated with hace1 loss of function to the expression of the Rho small family GTPase, rac1, which is a known target of HACE1 and promotes ROS production via its interaction with NADPH oxidase holoenzymes. Results: We demonstrate that loss of hace1 in zebrafish via morpholino knockdown results in cardiac deformities, specifically a looping defect, where the heart is either tubular or “inverted”. Whole‐mount in situ hybridization of cardiac markers shows distinct abnormalities in ventricular morphology and atrioventricular valve formation in the hearts of these morphants, as well as increased expression of rac1. Importantly, this phenotype appears to be directly related to Nox enzyme–dependent ROS production, as both genetic inhibition by nox1 and nox2 morpholinos or pharmacologic rescue using ROS scavenging agents restores normal cardiac structure. Conclusions: Our study demonstrates that HACE1 is critical in the normal development and proper function of the vertebrate heart via a ROS‐dependent mechanism. Developmental Dynamics 247:289–303, 2018. © 2017 Wiley Periodicals, Inc.
Clonality disguises the vulnerability of a threatened arid zone Acacia
Authors: Roberts David G. , Forrest Cairo N. , Denham Andrew J. , Ayre David J.
Published: October 2017

Long‐lived, widespread plant species are expected to be genetically diverse, reflecting the interaction between large population sizes, overlapping generations, and gene flow. Such species are thought to be resilient to disturbance, but may carry an extinction debt due to reproductive failure. Genetic studies of Australian arid zone plant species suggest an unusually high frequency of asexuality, polyploidy, or both. A preliminary AFLP genetic study implied that the naturally fragmented arid zone tree, Acacia carneorum, is almost entirely dependent on asexual reproduction through suckering, and stands may have lacked genetic diversity and interconnection even prior to the onset of European pastoralism. Here we surveyed microsatellite genetic variation in 20 stands to test for variation in life histories and further assessed the conservation status of the species by comparing genetic diversity within protected stands in National Parks and disturbed range lands. Using herbarium records, we estimate that 219 stands are extant, all of which occur in the arid zone, west of the Darling River in southeastern Australia. With two exceptions, all surveyed stands comprised only one multilocus genet and at least eight were putatively polyploid. Although some stands comprise thousands of stems, our findings imply that the species as a whole may represent ~240 distinct genetic individuals, many of which are polyploid, and most are separated by >10 km of unsuitable habitat. With only 34% of stands (and therefore genets) occurring within conservation reserves, A. carneorum may be at much greater risk of extinction than inferred from on‐ground census data. Land managers should prioritize on‐ground preservation of the genotypes within existing reserves, protecting both vegetative suckers and seedlings from herbivory. Importantly, three stands are known to set viable seed and should be used to generate genetically diverse germ‐plasm for ex situ conservation, population augmentation, or translocation.
Transgene flow in Mexican maize revisited: Socio‐biological analysis across two contrasting farmer communities and seed management systems
Authors: Agapito‐Tenfen Sarah , Lopez Flor R. , Mallah Narmeen , Abou‐Slemayne Gretta , Trtikova Miluse , Nodari Rubens O. , Wickson Fern
Published: October 2017

The flow of transgenes into landraces and wild relatives is an important biosafety concern. The case of transgene flow into local maize varieties in Mexico (the center of origin of maize) has been intensively debated over the past 15 years, including legal, political, and environmental disputes fanned by the existence of a significant scientific controversy over the methods used for the detection of transgenes. The use of diverse approaches and a lack of harmonized methods specific to the detection and monitoring of transgenes in landraces have generated both positive and negative results regarding contamination of Mexican maize with genetically modified material over the years. In this paper, we revisit the case of transgene contamination in Mexican maize and present a novel research approach based on socio‐biological analysis of contrasting communities and seed management systems. Two communities were used to investigate how different social and biological factors can affect transgene flow and impact transgene spread in Mexico. Our results show the presence of transgenes in one community and thus support the position that transgenes are highly likely to be present in Mexican maize landraces. However, our work also demonstrates that the extent and frequency with which transgenes can be found will significantly depend on the societal characteristics and seed management systems of the local communities. Therefore, we argue that future analysis of transgene presence should include social research on the seed management practices in the sampling area so that more robust and comprehensive understandings and conclusions can be drawn.
Tree species distribution in temperate forests is more influenced by soil than by climate
Authors: Walthert Lorenz , Meier Eliane Seraina
Published: October 2017

Knowledge of the ecological requirements determining tree species distributions is a precondition for sustainable forest management. At present, the abiotic requirements and the relative importance of the different abiotic factors are still unclear for many temperate tree species. We therefore investigated the relative importance of climatic and edaphic factors for the abundance of 12 temperate tree species along environmental gradients. Our investigations are based on data from 1,075 forest stands across Switzerland including the cold‐induced tree line of all studied species and the drought‐induced range boundaries of several species. Four climatic and four edaphic predictors represented the important growth factors temperature, water supply, nutrient availability, and soil aeration. The climatic predictors were derived from the meteorological network of MeteoSwiss, and the edaphic predictors were available from soil profiles. Species cover abundances were recorded in field surveys. The explanatory power of the predictors was assessed by variation partitioning analyses with generalized linear models. For six of the 12 species, edaphic predictors were more important than climatic predictors in shaping species distribution. Over all species, abundances depended mainly on nutrient availability, followed by temperature, water supply, and soil aeration. The often co‐occurring species responded similar to these growth factors. Drought turned out to be a determinant of the lower range boundary for some species. We conclude that over all 12 studied tree species, soil properties were more important than climate variables in shaping tree species distribution. The inclusion of appropriate soil variables in species distribution models allowed to better explain species' ecological niches. Moreover, our study revealed that the ecological requirements of tree species assessed in local field studies and in experiments are valid at larger scales across Switzerland.
Incubation behavior adjustments, driven by ambient temperature variation, improve synchrony between hatch dates and caterpillar peak in a wild bird population
Authors: Simmonds Emily G. , Sheldon Ben C. , Coulson Tim , Cole Ella F.
Published: October 2017

For organisms living in seasonal environments, synchronizing the peak energetic demands of reproduction with peak food availability is a key challenge. Understanding the extent to which animals can adjust behavior to optimize reproductive timing, and the cues they use to do this, is essential for predicting how they will respond to future climate change. In birds, the timing of peak energetic demand is largely determined by the timing of clutch initiation; however, considerable alterations can still occur once egg laying has begun. Here, we use a wild population of great tits (Parus major) to quantify individual variation in different aspects of incubation behavior (onset, duration, and daily intensity) and conduct a comprehensive assessment of the causes and consequences of this variation. Using a 54‐year dataset, we demonstrate that timing of hatching relative to peak prey abundance (synchrony) is a better predictor of reproductive success than clutch initiation or clutch completion timing, suggesting adjustments to reproductive timing via incubation are adaptive in this species. Using detailed in‐nest temperature recordings, we found that postlaying, birds improved their synchrony with the food peak primarily by varying the onset of incubation, with duration changes playing a lesser role. We then used a sliding time window approach to explore which spring temperature cues best predict variance in each aspect of incubation behavior. Variation in the onset of incubation correlated with mean temperatures just prior to laying; however, incubation duration could not be explained by any of our temperature variables. Daily incubation intensity varied in response to daily maximum temperatures throughout incubation, suggesting female great tits respond to temperature cues even in late stages of incubation. Our results suggest that multiple aspects of the breeding cycle influence the final timing of peak energetic demand. Such adjustments could compensate, in part, for poor initial timing, which has significant fitness impacts.
Biological soil crusts determine the germination and growth of two exotic plants
Authors: Song Guang , Li Xinrong , Hui Rong
Published: October 2017

In arid and semiarid ecosystems, the potential threats of exotic invasive species are enhanced due to increasing human activities. Biological soil crusts (BSCs), acting as arid ecosystem engineers, may play an important role in preventing the establishment of exotic invasive plants. Our goal was to examine whether BSCs could inhibit the establishment of probable exotic plant species originating from adjacent grasslands located along the southeast edge of the Tengger Desert. In our study, we investigated the effects of three BSC types (cyanobacteria, lichen, and moss crusts) under two disturbance conditions (intact and disturbed) on the establishment of two exotic plant species (Ceratoides latens and Setaria viridis) using indoor experiments. We found both negative and positive effects of BSCs on the establishment of the two exotic plant species. Compared with the disturbed BSCs, the germination percentages of C. latens and S. viridis were reduced by 54% to 87% and 89% to 93%, respectively, in intact BSCs. In contrast, BSCs significantly promoted the height growth and aboveground biomass of the two exotic plant species (p < .05) by enhancing the soil water and nutrient availability for the exotic plants. Our results confirm that BSCs strongly suppress the rapid expansion of exotic plant populations by inhibiting germination of seed with big size or appendages and have a weak inhibitory effect on exotic plant with small and smooth seeds. This may decrease the threat of propagation of exotic species. In the meantime, BSCs promote the growth of a few successful engraftment seedlings, which increased the beta diversity. Our work suggests that better understanding the two opposing effects of BSCs on the establishment of exotic plant species in different growth stages (germination and growth) is important for maintaining the health and stability of revegetated regions.
Bi‐dimensional null model analysis of presence‐absence binary matrices
Authors: Strona Giovanni , Ulrich Werner , Gotelli Nicholas J.
Published: October 2017

Comparing the structure of presence/absence (i.e., binary) matrices with those of randomized counterparts is a common practice in ecology. However, differences in the randomization procedures (null models) can affect the results of the comparisons, leading matrix structural patterns to appear either “random” or not. Subjectivity in the choice of one particular null model over another makes it often advisable to compare the results obtained using several different approaches. Yet, available algorithms to randomize binary matrices differ substantially in respect to the constraints they impose on the discrepancy between observed and randomized row and column marginal totals, which complicates the interpretation of contrasting patterns. This calls for new strategies both to explore intermediate scenarios of restrictiveness in‐between extreme constraint assumptions, and to properly synthesize the resulting information. Here we introduce a new modeling framework based on a flexible matrix randomization algorithm (named the “Tuning Peg” algorithm) that addresses both issues. The algorithm consists of a modified swap procedure in which the discrepancy between the row and column marginal totals of the target matrix and those of its randomized counterpart can be “tuned” in a continuous way by two parameters (controlling, respectively, row and column discrepancy). We show how combining the Tuning Peg with a wise random walk procedure makes it possible to explore the complete null space embraced by existing algorithms. This exploration allows researchers to visualize matrix structural patterns in an innovative bi‐dimensional landscape of significance/effect size. We demonstrate the rational and potential of our approach with a set of simulated and real matrices, showing how the simultaneous investigation of a comprehensive and continuous portion of the null space can be extremely informative, and possibly key to resolving longstanding debates in the analysis of ecological matrices.