bluuebunny/crossref_metadata_2025 huggingface dataset:
Children in Identified Sexual Images – Who Are they? Self‐ and Non‐Self‐Taken Images in the International Child Sexual Exploitation Image Database 2006–2015
Authors: Quayle Ethel , Jonsson Linda S. , Cooper Karen , Traynor James , Svedin Carl Göran
Published: March 2018

Child sexual abuse and exploitation material has drawn concern and legislative attention since the turn of the century, and the work to identify children in the images has been a prioritised task through international cooperation. The International Child Sexual Exploitation Image Database (ICSE DB) includes more than 8000 identified victims from nearly 50 countries. The database contains considerable important information about child abuse image crimes. The general aim of this study was to quantify the characteristics of children in identified illegal images from the UK ICSE DB (n = 687) with the subsidiary aim to describe differences between cases of self‐taken images and those whose images had been taken by others. The analysis showed an increase in identified victims during the study years 2006–2015. Almost two‐thirds were female, the majority were white and 44.3 per cent of images were self‐taken (34.4% taken in a coercive and 9.9% in a non‐coercive relationship). Since 2010, the number of self‐taken images each year has exceeded more than 40 per cent of the total number of images in the database. Although self‐taken images may be perceived as less worrisome, two‐thirds were classified as coercive. This is an important argument in favour of continuing to investigate these cases under victim identification programmes.

‘The general aim of this study was to quantify the characteristics of children in identified illegal images from the UK ICSE DB’

Key Practitioner Messages

The ICSE DB includes more than 8000 identified victims and contains important information about child abuse image crimes.

A majority of the identified victims were female and white children.

Almost half of all images were self‐taken and had been taken in a coercive relationship. Parents and practitioners need to recognise that even if a child sends sexual images these should be considered worrisome and therefore investigated further.
Are we in this Together? Post‐Separation Co‐Parenting of Fathers with and without a History of Domestic Violence
Authors: Thompson‐Walsh Catherine A. , Scott Katreena L. , Dyson Amanda , Lishak Victoria
Published: March 2018

This paper explores features of post‐separation co‐parenting from fathers' perspectives in men with and without a history of domestic violence (DV). Co‐parenting interview data from 20 fathers were randomly selected from a larger, longitudinal study (Fathers and Kids) conducted in Toronto, Canada, examining how domestically violent fathers impact children's development. Using thematic analysis, three themes were created for separated fathers without a history of DV: I value my ex‐partner's involvement with our child; we're good as co‐parents; and how we co‐parent impacts our child. Two themes were created for DV fathers: my ex‐partner is a bad mother; and my ex‐partner is responsible for our difficulties co‐parenting. These themes indicate markedly different perspectives between the two groups, specifically in valuing versus disparaging their ex‐partner, cooperation versus blame, and recognition versus no recognition of the potential impact of ongoing co‐parenting conflict on children. The nature of the differences between groups highlights the need to assess and support fathers with a history of DV as co‐parents, and indicates possible targets of intervention for fathering programmes.

‘Explores features of post‐separation co‐parenting from fathers' perspectives in men with and without a history of domestic violence’

Key Practitioner Messages

For most fathers with a history of DV perpetration, co‐parenting problems persisted post‐separation.

Narratives of most DV fathers demonstrated overwhelmingly negative evaluations of ex‐partners, predominant patterns of blaming mothers for difficulties and lack of insight into the impact of co‐parenting conflict on children.

Decisions about the involvement of DV fathers post‐separation should be preceded by thorough and ongoing assessment and, for those with ongoing contact, support in order to safely and effectively co‐parent.
Recognition and Conformational Properties of an Alternative Antithrombin Binding Sequence Obtained by Chemoenzymatic Synthesis
Authors: Stancanelli Eduardo , Elli Stefano , Hsieh Po‐Hung , Liu Jian , Guerrini Marco
Published: March 2018

Heparin is a highly sulfated glycosaminoglycan (GAG) of natural origin used as an anticoagulant and antithrombotic drug. These properties are principally based on the binding and activation of antithrombin (AT) through the pentasaccharide sequence GlcNAc/NS,6S‐GlcA‐GlcNS,3,6S‐IdoA2S‐GlcNS,6S (AGA*IA). Literature data show that the population of the 2S0 ring conformation of the 2‐O‐sulfo‐α‐l‐iduronic acid (IdoA2S) motif correlates with the affinity and activation of AT. It was recently demonstrated that two synthetic AGA*IA‐containing hexasaccharides (one G unit added at the reducing end), differing in the degree of sulfation of the IdoA unit, show comparable affinity and ability to activate AT, despite a different conformation of the IdoA residue. In this paper, the binding of these two glycans to AT was studied by isothermal titration microcalorimetry (ITC), transferred (tr‐) NOESY, saturation transfer difference (STD) NMR spectroscopy and molecular dynamics (MD) simulations. Results indicated that both the IdoA2S and the IdoA units assume a 2S0 conformation when bound with AT, and so present a common binding epitope for the two glycans, centred on the AGA*IA sequence.
Comparison of the planned one‐ and elective two‐stent techniques in patients with coronary bifurcation lesions with or without acute coronary syndrome from the COBIS II Registry
Authors: Kim Min Chul , Ahn Youngkeun , Sun Sim Doo , Joon Hong Young , Han Kim Ju , Ho Jeong Myung , Gwon Hyeon‐Cheol , Kim Hyo‐Soo , Rha Seung Woon , Yoon Jung Han , Jang Yangsoo , Tahk Seung‐Jea , Seung Ki Bae
Published: March 2018

Objectives

To evaluate the impacts of stent techniques on long‐term clinical outcomes after percutaneous coronary intervention (PCI) using drug‐eluting stents (DES) for coronary bifurcation lesions in patients with or without acute coronary syndrome (ACS).

Background

Few studies have investigated the impacts of stent techniques for treating coronary bifurcation lesions in patients with and without ACS.

Methods

This multicenter registry enrolled 2,897 patients undergoing PCI with DES for coronary bifurcation lesions. We investigated the impacts of planned one‐stent and elective two‐stent techniques in patients with (n = 1,798) and those without (n = 1,099) ACS. Primary endpoint was the incidence of 3‐year target‐lesion failure (TLF), defined as a composite of cardiac death, spontaneous myocardial infarction, and target‐lesion revascularization.

Results

The planned one‐stent technique reduced TLF rate compared to elective two‐stent technique in the ACS cohort (hazard ratio [HR] 0.49; 95% confidence interval [CI] 0.34–0.74; P = 0.001), and not in the non‐ACS cohort (HR 0.61; 95% CI 0.35–1.06; P = 0.079). After propensity score matching, the planned one‐stent technique had a significantly lower TLF rate (HR 0.47; 95% CI 0.29–0.74; P = 0.001) in patients with ACS, and it also showed a trend toward lower TLF rate with the planned one‐stent technique in patients without ACS (9.0 vs. 14.5%, HR 0.59; 95% CI 0.32–1.14; P = 0.116).

Conclusions

Planned one‐stenting reduced TLF in patients with ACS and it also might be beneficial in those without ACS for the treatment of coronary bifurcation lesions.
Treatment of infrapopliteal post‐PTA dissection with tack implants: 12‐month results from the TOBA‐BTK study
Authors: Brodmann Marianne , Wissgott Christian , Holden Andrew , Staffa Robert , Zeller Thomas , Vasudevan Thodur , Schneider Peter
Published: March 2018

Objectives

The Tack implant is designed for focal, minimal metal management of dissections. This study evaluated Tacks for treating postpercutaneous transluminal angioplasty (PTA) dissection in patients with below‐the‐knee (BTK) arterial occlusive disease.

Background

PTA is the most commonly used endovascular treatment for patients with occlusive disease of the BTK vessels. Post‐PTA dissection is a significant clinical problem that results in poor outcomes, but currently there are limited treatment options for managing dissections.

Methods

This prospective, single‐arm study evaluated patients with CLI and BTK lesions; 11.4% were Rutherford category (RC) 4 and 88.6% were RC 5. BTK occlusive disease was treated with standard PTA and post‐PTA dissections were treated with Tack placement. The primary safety endpoint was a composite of major adverse limb events (MALE) and perioperative death (POD) at 30 days. Other endpoints included: device success; procedure success (vessel patency in the absence of MALE); freedom from clinically driven target lesion revascularization (CD‐TLR); primary patency; and changes in RC. Data through 12 months are presented.

Results

Thirty‐two of 35 (91.4%) patients had post‐PTA dissection and successful deployment of Tacks. Procedural success was achieved in 34/35 (97.1%) patients with no MALEs at 30 days. The 12‐month patency rate was 78.4% by vessel, 77.4% by patient, and freedom from CD‐TLR was 93.5%. Significant (P < .0001) improvement from baseline was observed in RC (75% of patients improved 4 or 5 steps).

Conclusion

Tack implant treatment of post‐PTA dissection was safe and effective for treatment of BTK dissections and resulted in reasonable 12‐month patency and low rates of CD‐TLR.
Recent Advances in Catalysis with Transition‐Metal Pincer Compounds
Authors: Valdés Hugo , García‐Eleno Marco A. , Canseco‐Gonzalez Daniel , Morales‐Morales David
Published: March 2018

Pincer complexes are useful tools for organic synthesis. Their high stability and easy functionalization have allowed the development of novel catalytic systems that have had a tremendous impact in different areas of chemistry. Thus, catalytic reactions are nowadays a fundamental part of several synthetic routes, as they allow “greener” procedures with high atom efficiency. In this context, pincer complexes have contributed to the establishment of novel and efficient catalytic reactions. Thus, herein we summarize the most recent relevant advances involving pincer complexes as catalysts.
Evidence of Hybrid Homogeneous–Heterogeneous Catalysis in a Pt/Au Heterobimetallic System
Authors: Alonso José Miguel , Paz Muñoz María
Published: March 2018

We report here our efforts towards understanding the catalytic species involved in a novel Pt/Au heterobimetallic system capable of efficiently catalysing the tandem cyclisation/C−X coupling reaction of heteroarylallenes with C‐ and N‐based nucleophiles. Our results confirm that homogeneous Au‐catalysis is involved at the beginning of the reaction to generate an intermediate that enters the second catalytic cycle in which hybrid homogeneous–heterogeneous catalysis by [Pt–Au] clusters could be responsible for the high efficiency. In this part of the cycle, [Pt–AuPPh3] homogeneous clusters (identified by 31P NMR analysis) seem to be aided by Pt–Au particles in the heterogeneous phase (supported by Hg poisoning, filtration experiments and characterisation of the possible catalytic species by several techniques, such us 31P NMR spectroscopy, inductively coupled plasma mass spectrometry, SEM and dynamic light scattering experiments). Here, full Pt‐to‐Au transmetallation was not observed contrary to the results with other bimetallic systems. Although a few examples of hybrid homogeneous–heterogeneous catalysis in monometallic systems exist, to the best of our knowledge, this is the first example of hybrid homogeneous–heterogeneous catalysis in systems involving two different metals.
Rational Design and Fabrication of Noble‐metal‐free NixP Cocatalyst Embedded 3D N‐TiO2/g‐C3N4 Heterojunctions with Enhanced Photocatalytic Hydrogen Evolution
Authors: Wu Mao , Zhang Jin , Liu Chunxiao , Gong Yansheng , Wang Rui , He Beibei , Wang Huanwen
Published: March 2018

Developing low‐cost and efficient noble‐metal‐free photocatalytic materials is crucial for the hydrogen production through water splitting. Herein, N‐TiO2/g‐C3N4 heterostructure loaded with a noble‐metal‐free NixP cocatalyst was prepared by the combination of ammonia etching and photo‐reduction deposition method. The results demonstrated that N‐doped TiO2 (N‐TiO2) nanosheets were formed and stood upright on the surfaces of g‐C3N4 nanosheets, forming a 3D structure. The ternary hybridization of N‐TiO2/g‐C3N4@NixP hierarchical nanostructure was a promising strategy to achieve highly efficient photocatalytic H2 evolution, showing an optimized hydrogen evolution rate of 5438 μmol g−1⋅h−1 using 300 W Xe lamp as irradiation source, which was 7.5 times higher than that of N‐TiO2/g‐C3N4. The enhanced photocatalytic activity was ascribed to the combined effects of NixP cocatalyst loading and the formation of the intimate nanoheterojunctions between TiO2 nanosheets and g‐C3N4 nanosheets, which were favorable for promoting charge transfer. The present work would provide a novel facile preparation and practical application of many other noble‐metal‐free metal phosphides as a highly efficient cocatalyst for hydrogen production through water splitting.
Application of N‐Doped MoS2 Nanocrystals for Removal of Azo Dyes in Wastewater
Authors: Lu Haijiao , Wang Jingkang , Tian Beiqian , Huang Xin , Bi Jingtao , Wang Ting , Hao Hongxun
Published: March 2018

As persistent and detrimental contaminants, azo dyes are difficult to be removed from wastewater. It is a worldwide challenge to develop efficient technologies for their removal. Adsorption is widely recognized to be a practical, efficient, and low‐cost technology for removal of contaminants. Compared with various conventional adsorbents, MoS2 nanocrystals possess larger specific surface area, higher surface energy, and better adsorptive properties. Since nitrogen‐doping is a common approach for modification of materials, N‐doped MoS2 nanocrystals (NDMN) were first used as adsorbents for removal of the azo dye methyl orange. Compared with bulk MoS2 and MoS2 nanocrystals, NDMN showed much higher efficiency and reusability. This study provides inspiration for exploring and expanding the applications of NDMN.
Cyanidation of Gold Associated with Silver Minerals in Sulfide Mineral Matrices
Authors: Khalid Muhammad , Larachi Faïçal , Adnot Alain
Published: March 2018

Lead salt stimulated the dissolution of gold when gold associated with silver minerals was interspersed in the silica or in the pyrite‐silica layer. Gold dissolution was likewise promoted through lead addition for chalcopyrite‐silica and the sphalerite‐silica systems. Lead addition did not boost gold dissolution and a recovery of 6.9 % was achieved for gold and silver minerals dispersed in stibnite. Lead pretreatment also enhanced gold recovery except for the stibnite‐silica system. Gold surface‐passivating films were observed for gold associated with silver minerals and stibnite.
Growth Rate Measurements of Organic Crystals in a Cone‐Shaped Fluidized‐Bed Cell
Authors: Ostermann Marie-Christine , Termühlen Maren , Schembecker Gerhard , Wohlgemuth Kerstin
Published: March 2018

Knowledge of crystal growth rates and the factors that affect these rates is often an essential prerequisite for designing industrial processes that yield a desired crystalline product. Herein, the effects of saturation temperature, supersaturation, and seed‐crystal size on the overall linear growth rate of L‐alanine were examined by using a cone‐shaped fluidized‐bed cell. For a systematic investigation, a “design of experiment” approach was applied that used a two‐level full‐factorial design. It was found that the interaction effects of the three factors mentioned above play a considerable role in interpreting the effect of each individual factor on the growth rate. These interaction effects must be considered when gaining knowledge of crystal growth for the purpose of process design.
Molecular Dynamics Investigation of the Dielectric Decrement of Ion Solutions
Authors: Pache Dennis , Schmid Rochus
Published: March 2018

Molecular dynamics simulations, using a classical force field model, have been used to determine the dependence of the static relative dielectric constant of ion solutions with respect to the nature and concentration of the ions and the field strength. The experimentally observed effect of a reduction of the dielectric permittivity due to solvated ions is known as dielectric decrement. We used both the polarization fluctuation at zero field and the constant dielectric displacement method for finite fields to determine the dielectric constant of the bulk solution. All the experimentally observed tendencies of the dielectric decrement could be qualitatively reproduced. The analysis of different solute solvent radial distribution functions indicate that the dielectric decrement arises from the competition between the macroscopic electric field and the local water‐ion interaction. The results suggest that the electric field eventually manages to overcome the local molecular interactions, breaking up the structure of the solvation shell and thus lowering the ion's effect on the dielectric constant. This effect seems to correlate with the solvation energy of the individual ions as well as the type of counter ion, indicating that also long range interactions might play a role. The results can be used to improve especially continuum electrolyte models, used to study electrochemical interfaces, where currently the dielectric decrement is generally not included.
Ni12P5 Nanoparticles Hinged by Carbon Nanotubes as 3D Mesoporous Anodes for Lithium‐Ion Batteries
Authors: Wang Bei , Ru Qiang , Su Chiquan , Cheng Shikun , Liu Peng , Guo Qing , Hou Xianhua , Su Shichen , Ling Francis Chi‐Chung
Published: March 2018

A unique 3D mesoporous interconnected Ni12P5/CNTs hybrid was constructed by a facile one‐step hydrothermal method and investigated as anode toward lithium‐ion batteries. The results show that Ni12P5 nanoparticles are well hinged by the flexible CNTs, forming a hierarchically integrated structure. The system delivers an initial discharge capacity of 1108 mAh g−1 and a high reversible discharge capacity of 676 mAh g−1 after 120 cycles at 200 mA g−1. Furthermore, the hybrid also achieved long‐term cycling stability and good rate capability, such as 584 mAh g−1 at a current density of 400 mA g−1 after 240 cycles and 245 mAh g−1 at a rate current density of 3200 mA g−1. The enhanced electrochemical performance could be attributed to the synergistic effect of increased specific surface area, mesoporous structures, and 3D interconnected conductive network
Strictly conservative expected values in the case of heteroscedastic errors and their application to evidential breath alcohol confidence intervals for concentration measurements
Authors: Taavitsainen Veli‐Matti , Muuriaisniemi‐Skippari Kirsi , Gunnar Teemu , Ihalainen Heikki
Published: March 2018

In this study, 2 different methods for determining strictly conservative confidence intervals for expected values in the case of heteroscedastic errors are presented. A conservative confidence interval means that a given false positive error rate is not exceeded. The novelty in both approaches is in carrying out the required approximations in such a way that this property holds. The other method is based on variance stabilizing transformations and given as 2 variants, Transformation Models I and II. For variant II, a rigorous proof is given to show that a given false positive error rate is not exceeded if the underlying distributional assumptions are valid. The second method is based on modeling the variance as a function of the expected value, and this is also given as 2 variants, Variance Models I and II. In all cases, only random errors are considered. The methods were tested and compared by applying them to a real case of breath alcohol concentration measurements performed by the Finnish law enforcement authorities, and also by simulation studies. The methods compared were studied by simulating a sample that had the same distributional properties as the real data. These studies showed that Variance Model I is overly conservative, and Variance Model II doesn't quite satisfy the set rate. Both transformation models give too many false positives at concentrations levels exceeding the prosecution limits, but in the range of prosecution limits they could be used.
Iron Precatalysts with Bulky Tri(tert‐butyl)cyclopentadienyl Ligands for the Dehydrocoupling of Dimethylamine‐Borane
Authors: Turner Joshua , Chilton Nicholas F. , Kumar Amit , Colebatch Annie L. , Whittell George R. , Sparkes Hazel A. , Weller Andrew S. , Manners Ian
Published: March 2018

In an attempt to prepare new Fe catalysts for the dehydrocoupling of amine‐boranes and to provide mechanistic insight, the paramagnetic FeII dimeric complex [Cp′FeI]2 (1) (Cp′=η5‐((1,2,4‐tBu)3C5H2)) was used as a precursor to a series of cyclopentadienyl FeII and FeIII mononuclear species. The complexes prepared were [Cp′Fe(η6‐Tol)][Cp′FeI2] (2) (Tol=C6H5Me), [Cp′Fe(η6‐Tol)][BArF4] (3) (BArF4=[B(C6H3(m‐CF3)2)4]−), [N(nBu)4][Cp′FeI2] (4), Cp′FeI2 (5), and [Cp′Fe(MeCN)3][BArF4] (6). The electronic structure of the [Cp′FeI2]− anion in 2 and 4 was investigated by SQUID magnetometry, EPR spectroscopy and ab initio Complete Active Space Self Consistent Field‐Spin Orbit (CASSCF‐SO) calculations, and the studies revealed a strongly anisotropic S=2 ground state. Complexes 1–6 were investigated as catalysts for the dehydrocoupling of Me2NH⋅BH3 (I) in THF at 20 °C to yield the cyclodiborazane product [Me2N‐BH2]2 (IV). Complexes 1–4 and 6 were active dehydrocoupling catalysts towards I (5 mol % loading), however 5 was inactive, and ultra‐violet (UV) irradiation was required for the reaction mediated by 3. Complex 6 was found to be the most active precatalyst, reaching 80 % conversion to IV after 19 h at 22 °C. Dehydrocoupling of I by 1–4 proceeded via formation of the aminoborane Me2N=BH2 (II) as the major intermediate, whereas for 6 the linear diborazane Me2NH‐BH2‐NMe2‐BH3 (III) could be detected, together with trace amounts of II. Reactions of 1 and 6 with Me3N⋅BH3 were investigated in an attempt to identify Fe‐based intermediates in the catalytic reactions. The σ‐complex [Cp′Fe(MeCN)(κ2‐H2BH⋅NMe2H][BArF4] was proposed to initially form in dehydrocoupling reactions involving 6 based on ESI‐MS (ESI=Electrospray Ionisation Mass Spectroscopy) and NMR spectroscopic evidence. The latter also suggests that these complexes function as precursors to iron hydrides which may be the true catalytic species.
Structure of Ancient Glass by 29Si Magic Angle Spinning NMR Spectroscopy
Authors: Bradford Henry , Ryder Amy , Henderson Julian , Titman Jeremy J.
Published: March 2018

29Si magic angle spinning (MAS) NMR spectroscopy has been applied for the first time to the structural analysis of ancient glass samples obtained from archaeological excavations. The results show that it is possible to establish the distribution of Si environments in ancient glass by 29Si MAS NMR, so long as the concentrations of magnetic impurities, such as Mn and Fe oxides, are low. In general, good agreement has been obtained with compositions determined by means of electron probe microanalysis. In addition, the 29Si MAS NMR data reveal structural differences between glasses manufactured at separate ancient sites.
Halogen, Chalcogen, and Pnicogen Bonding Involving Hypervalent Atoms
Authors: Scheiner Steve , Lu Jia
Published: March 2018

The additional substituents arising from hypervalency present a number of complicating issues for the formation of noncovalent bonds. The XF5molecule (X=Cl, Br, I) was allowed to form a halogen bond with NH3as the base. Hypervalent chalcogen bonding is examined by way of YF4and YF6(Y=S, Se, Te), and ZF5(Z=P, As, Sb) is used to model pnicogen bonding. Pnicogen bonds are particularly strong, with interaction energies approaching 50 kcal mol−1, and also involve wholesale rearrangement from trigonal bipyramidal in the monomer to square pyramidal in the complex, subject to a large deformation energy. YF4chalcogen bonding is also strong, and like pnicogen bonding, is enhanced by a heavier central atom. XF5halogen bond energies are roughly 9 kcal mol−1, and display a unique sensitivity to the identity of the X atom. The crowded octahedral structure of YF6permits only very weak interactions. As the F atoms of SeF6are replaced progressively by H, a chalcogen bond appears in combination with SeH⋅⋅⋅N and NH⋅⋅⋅F H‐bonds. The strongest such chalcogen bond appears in SeF3H3⋅⋅⋅NH3, with a binding energy of 7 kcal mol−1, wherein the base is located in the H3face of the Lewis acid. Results are discussed in the context of the way in which the positions and intensities of σ‐holes are influenced by the locations of substituents and lone electron pairs.
An Improved Approach to the Direct Construction of 2‐Deoxy‐β‐Linked Sugars: Applications to Oligosaccharide Synthesis
Authors: Lloyd Dina , Bennett Clay S.
Published: March 2018

A next‐generation reagent‐controlled approach for the synthesis of 2,6‐dideoxy and 2,3,6‐trideoxy sugar donors in good yield and high β‐selectivity is reported. The use of p‐toluenesulfonyl chloride and potassium hexamethyldisilazide (KHMDS) greatly simplifies deoxy‐sugar glycoside construction, and can be used for gram‐scale glycosylation reactions. The development of this approach and its application to the construction of β‐linked deoxy‐sugar oligosaccharides are described.
Synthesis and Structure of a Stable Bis(methylene)‐λ4‐sulfane
Authors: Sugamata Koh , Hashizume Daisuke , Suzuki Yuko , Sasamori Takahiro , Ishii Shigeru
Published: March 2018

Bis(methylene)‐λ4‐sulfane 1, a >C=S=C< heterocumulene, was obtained as a red crystalline solid from the reaction between elemental sulfur and a carbenoid that contains sterically demanding silylalkyl groups. Under atmospheric conditions, and even at elevated temperatures, 1 exhibits extraordinary stability. The molecular structure and electron‐density distribution of 1 were analyzed by single‐crystal X‐ray diffraction analysis, which revealed a bent C=S=C geometry with C=S=C π‐bonds. These results, combined with those of variable‐temperature NMR measurements and theoretical calculations suggest a slow rotation of the S=C moieties in 1, the stability and structure of which were further examined by theoretical calculations.
Bioinspired Design of Fe3+‐Doped Mesoporous Carbon Nanospheres for Enhanced Nanozyme Activity
Authors: Sang Yanjuan , Huang Yanyan , Li Wei , Ren Jinsong , Qu Xiaogang
Published: March 2018

Nanozymes have received considerable attention as alternatives of natural enzymes. However, the catalytic activity of nanozymes is often lower than that of natural enzymes, which largely limits their applications. Current methods utilized to improve the catalytic efficiency and substrate selectivity of a nanozyme usually have some inherent drawbacks. Herein, a biomimetic strategy was developed to design Fe3+‐doped mesoporous carbon nanospheres (Fe3+‐MCNs) as a horseradish peroxidase (HRP) mimic to realize the structure and function mimicking of natural HRP. In this system, Fe3+ ions could act as catalytic centers and carboxyl‐modified mesoporous carbon nanospheres (MCNs‐COOH) could be used to bind with substrates. As a result, Fe3+‐MCNs showed higher enzymatic activity than that of Fe3O4 nanoparticles. Therefore, this strategy can contribute to the development of nanozymes and further understanding of the complicated enzymatic reactions in natural and biological systems.
Self‐Assembled Bright Luminescent Lanthanide‐Organic Polyhedra for Ratiometric Temperature Sensing
Authors: Guo Xiao‐Qing , Zhou Li‐Peng , Cai Li‐Xuan , Sun Qing‐Fu
Published: March 2018

Luminescent lanthanide‐containing compounds have a lot of stimulating applications. However, the fine‐tuning of the optical properties of multi‐nuclear lanthanide edifices is still a big challenge. We report here the coordination self‐assembly of a group of bright luminescent lanthanide organic polyhedra (LOPs) with record high emission quantum yields, by using two fully‐conjugated ligands featuring the triazole‐pyridine‐amido (tpa) chelating moiety, easily‐accessible from the “Click” reaction. The self‐assembled LOPs are characterized by NMR spectroscopy, high‐resolution ESI‐TOF‐MS, and X‐ray crystallography. Interestingly, inter‐metal energy transfer (ET) is confirmed on the mixed‐lanthanide polyhedral molecules, though the metal centers are separated nearly 2 nm apart. A feasible ratiometric luminescent thermometer, with work range from cryogenic to physiological temperatures, has been demonstrated with the mixed Eu/Tb LOPs. We envisage these molecular‐level bright luminescent LOPs have great application potential in displaying, labelling/imaging, up‐conversion materials etc.
Nonvolatile Tri‐State Resistive Memory Behavior of a Stable Pyrene‐Fused N‐Heteroacene with Ten Linearly‐Annulated Rings
Authors: Li Yang , Zhang Cheng , Gu Peiyang , Wang Zilong , Li Zhengqiang , Li Hua , Lu Jianmei , Zhang Qichun
Published: March 2018

The diverse functionalities of large N‐heteroacenes continue to be developed in terms of their strategic synthesis and application in the organic electronic field. Here, we report a novel large stable pyrene‐containing N‐heteroacene with ten linearly‐annulated rings in one row. Remarkably, it exhibited excellent tri‐state resistive memory property, which held great promise to achieve ultrahigh‐density data storage. To the best of our knowledge, it is the first demonstration of organic multistate memory device based on large N‐heteroacene (n≥10), which provides guidelines for designing more proof‐of‐concept larger N‐heteroacene‐based memory electronics.
A Facile Synthesis of Blue Luminescent [7]Helicenocarbazoles Based on Gold‐Catalyzed Rearrangement‐Iodonium Migration and Suzuki–Miyaura Benzannulation Reactions
Authors: Alcaide Benito , Almendros Pedro , Aragoncillo Cristina , Busto Eduardo , López‐Calixto Carmen G. , Liras Marta , de la Peña O'Shea Víctor A. , García‐Sánchez Alba , Stone Hannah V.
Published: March 2018

New azahelicenes having interesting photophysical properties have been prepared in a four‐step sequence. These [7]helicenocarbazoles are efficient blue luminophores, demonstrating the utility of gold catalysis in the preparation of advanced materials.
Iridium‐Catalyzed Aerobic Coupling of Salicylaldehydes with Alkynes: A Remarkable Switch of Oxacyclic Product
Authors: Yamane Shintaro , Hinoue Tomoaki , Usuki Yoshinosuke , Itazaki Masumi , Nakazawa Hiroshi , Hayashi Yoshihiro , Kawauchi Susumu , Miura Masahiro , Satoh Tetsuya
Published: March 2018

The iridium(III)/copper(II)‐catalyzed dehydrogenative coupling of salicylaldehydes with internal alkynes proceeds efficiently under atmospheric oxygen through aldehyde C−H bond cleavage and decarbonylation. A variety of benzofuran derivatives can be synthesized by the environmentally benign procedure. DFT calculations suggest that this unique transformation involves the facile deinsertion of CO in the key metallacycle intermediate, which is in marked contrast to the corresponding rhodium(III) catalysis that leads to CO‐retentive chromone derivatives.
5‐Aza‐7‐deaza‐2′‐deoxyguanosine and 2′‐Deoxycytidine Form Programmable Silver‐Mediated Base Pairs with Metal Ions in the Core of the DNA Double Helix
Authors: Guo Xiurong , Leonard Peter , Ingale Sachin A. , Liu Jiang , Mei Hui , Sieg Martha , Seela Frank
Published: March 2018

5‐Aza‐7‐deaza‐2′‐deoxyguanosine (dZ) forms a silver‐mediated base pair with dC. The metal ion pair represents a mimic of the H‐bonded Watson–Crick dG‐dC pair. The modified nucleoside displays a similar shape as the parent 2′‐deoxyguanosine from which it can be constructed by transposition of nitrogen‐7 to the bridgehead position‐5. It lacks the major groove binding site as the positional change moves the dG‐ acceptor position from nitrogen‐7 to nitrogen‐1. As a shape mimic of dG, it fits nicely in the DNA double helix. The purine–pyrimidine dZ‐dC hetero pair shows a relationship to the pyrimidine–pyrimidine dC‐dC homo base pair. The dZ‐dC pair forms a mismatch in the absence of silver ions and matches after addition of metal ions. Base‐pair formation was verified on self‐complementary 6‐mer duplexes and 12‐mer DNA with random composition by UV‐dependent Tm measurements. Modified silver‐mediated and hydrogen‐bonded canonical base pairs can coexist. The dZ‐Ag+‐dC base pair is slightly less stable than the dG‐dC pair, shows sequence dependence, and consumes one or two silver ions. These properties make the dZ‐Ag+‐dC pair suitable for programmable incorporation of silver ions in DNA which cannot be achieved by canonical base pairs. If the silver ion content is higher than the total number of base pairs the duplexes turn into very stable structures in which all base pairs are considered to be in the silver‐mediated pairing mode.
Total Synthesis of Lapidilectine B Enabled by Manganese(III)‐Mediated Oxidative Cyclization of Indoles
Authors: Gao Yang , Fan Mengyang , Geng Qixiang , Ma Dawei
Published: March 2018

A novel manganese(III)‐mediated oxidative cyclization of readily accessible 1,2,3‐trisubstituted indoles is described. This unprecedented method enabled the efficient construction of a complex polycyclic scaffold bearing a spiro‐indoline motif and a lactone moiety in one step. Its synthetic utility was demonstrated in the total synthesis of lapidilectine B (in 18 steps) by employing a strategic regioselective ring‐expansion and a silver‐promoted allenic amine cyclization as the additional key elements.
Solvent polarity effects on supramolecular chirality of a polyfluorene‐thiophene copolymer
Authors: Hirahara Takashi , Yoshizawa‐Fujita Masahiro , Takeoka Yuko , Rikukawa Masahiro
Published: March 2018

This study demonstrates the supramolecular chirality control of a conjugated polymer via solvent polarity. We designed and synthesized a chiral polyfluorene‐thiophene copolymer having two different chiral side chains at the 9‐position of the fluorene unit. Chiral cyclic and alkyl ethers with different polarities were selected as the chiral side chains. The sign of the circular dichroism spectra in the visible wavelength region was affected by the solvent system, resulting from the change of supramolecular structure. The estimation of the solubility parameter revealed that the solubility difference of the side chains contributed to the change of the circular dichroism sign, which was also observed in spin‐coated films prepared from good solvents having different polarities.
Functional characterization of salt‐tolerant microbial esterase WDEst17 and its use in the generation of optically pure ethyl (R)‐3‐hydroxybutyrate
Authors: Wang Yilong , Xu Yongkai , Zhang Yun , Sun Aijun , Hu Yunfeng
Published: March 2018

The two enantiomers of ethyl 3‐hydroxybutyrate are important intermediates for the synthesis of a great variety of valuable chiral drugs. The preparation of chiral drug intermediates through kinetic resolution reactions catalyzed by esterases/lipases has been demonstrated to be an efficient and environmentally friendly method. We previously functionally characterized microbial esterase PHE21 and used PHE21 as a biocatalyst to generate optically pure ethyl (S)‐3‐hydroxybutyrate. Herein, we also functionally characterized one novel salt‐tolerant microbial esterase WDEst17 from the genome of Dactylosporangium aurantiacum subsp. Hamdenensis NRRL 18085. Esterase WDEst17 was further developed as an efficient biocatalyst to generate (R)‐3‐hydroxybutyrate, an important chiral drug intermediate, with the enantiomeric excess being 99% and the conversion rate being 65.05%, respectively, after process optimization. Notably, the enantio‐selectivity of esterase WDEst17 was opposite than that of esterase PHE21. The identification of esterases WDEst17 and PHE21 through genome mining of microorganisms provides useful biocatalysts for the preparation of valuable chiral drug intermediates.
Prediction of Product Yields for Different Reactor Types in Catalytic Pyrolysis
Authors: Engelhardt Armin , Stam‐Creutz Timo , Hahn Thomas , Seitz Mathias
Published: March 2018

Für den Wandel hin zu einer postfossilen Gesellschaft werden rohstoffvariable Verfahren wie die katalytische Pyrolyse von festen Kohlenwasserstoffen benötigt. Zur Vorhersage der Produktausbeute aus unterschiedlichen Einsatzstoffen wurden Modellansätze entwickelt, die Rohstoffqualität, Katalysatoreigenschaften und Prozessbedingungen berücksichtigen. Eine gute Beschreibung für die stoffliche Nutzung von Braunkohle ist mit wenigen Einflussgrößen und signifikanten Modellparametern möglich. Perspektivisch sollen solche Modelle auf die Spaltung polyolefinischer Rezyklate und fettreiche Biomassen übertragen werden.
Generational Differences in the Importance, Availability, and Influence of Work Values: A Public Service Perspective
Authors: Smith Christopher , Halinski Michael , Gover Laura , Duxbury Linda
Published: March 2018

This study uses a sample of 832 Canadian public servants to test a theoretically derived framework which hypothesizes that generational cohort: (1) predicts the importance public servants place on intrinsic and extrinsic work values, (2) predicts the perceived availability of such rewards in public service workplaces, and (3) impacts the relationship between perceived availability of important rewards, organizational commitment, and job satisfaction. Our study adds to the limited body of research on generational cohort and work values in the public service. Generational cohort had little impact on the importance of work values, but did predict perceived availability of work‐rewards and the relationship between perceived availability of important rewards, organizational commitment, and job satisfaction. Findings could help public service organizations' recruitment and retention efforts. Copyright © 2018 ASAC. Published by John Wiley & Sons, Ltd.
Design of internal model control dead‐time compensation scheme for first order plus dead‐time systems
Authors: Pathiran Arun R. , Jagadeesan Prakash
Published: March 2018

Internal model control (IMC) is a well‐known model‐based control structure that has additional dead‐time compensation (DTC), while PID is the popularly‐implemented control structure due to its simple structure, ease of implementation, and satisfactory performance at a wide range of operating conditions. Therefore, IMC‐based PID tuning methods are introduced to include the benefits of IMC in PID. Approximations involved in the existing IMC‐based PID tuning methods for specific types of transfer function models result in performance degradation. The IMC structure can be rearranged to the form of a standard PID type controller without approximation, which retains good servo performance for time delay processes. On the other hand, the presence of a time delay element in the controller structure makes the loop highly sensitive to dead‐time variations. Thus, the sensitivity of the IMC scheme realized in the PID structure is studied based on the conventional Nyquist stability criterion. It is observed that the high sensitivity is due to the occurrence of multiple interaction points of the Nyquist curve of the loop transfer function and unit circle. Besides, the number of the interaction points is relative to the ratio of loop dead‐time to closed loop time constant. Further, it is shown that the occurrence of multiple interaction points can be avoided by the right choice of closed loop time constant. The performance and robustness of the proposed design approach is confirmed via simulation analysis.
Y zeolite equilibrium catalyst waste from fluidized catalytic cracking regenerated by electrokinetic treatment: An adsorbent for sulphur and nitrogen compounds
Authors: de Oliveira Thamayne Valadares , Valt Renata Bachmann Guimarães , de Araújo Ponte Haroldo , de Santana Ponte Maria José Jerônimo , Yamamoto Carlos Itsuo , de Souza Antônio Augusto Ulson , de Arruda Guelli Ulson de Souza Selene Maria
Published: March 2018

The adsorption of sulphur, nitrogen, and aromatic compounds on a regenerated equilibrium catalyst (ecat‐R) was studied using model and real diesel fuels. The ecat‐R was obtained by electrokinetic treatment of an equilibrium catalyst (Y zeolites) waste from fluidized catalytic cracking (FCC) units. The studied model diesel fuel contained dibenzothiophene (1039 mg/L), quinoline (600 mg/L), and naphthalene (600 mg/L), as models for sulphur, nitrogen, and aromatic compounds, respectively, in n‐decane as solvent. The ecat‐R was characterized using X‐ray diffraction, X‐ray fluorescence, N2 adsorption‐desorption, thermogravimetric and differential thermal analysis, scanning electron microscopy, Fourier‐transform infrared spectroscopy, and granulometry. The adsorption experiments were performed at 40 °C and 150 rpm. The results of the isotherm and a chemical kinetics studies were favourable; the material showed a high adsorption capacity for dibenzothiophene (2.8 mg S/g) and quinoline (6.3 mg N/g). The isotherm for naphthalene was less favourable (2 mg NAP/g). The process rapidly reached equilibrium in approximately 2 h. For real diesel fuel, the adsorption removal was 26 % for sulphur and 36 % for nitrogen.
Goodness‐of‐fit tests for Lévy‐driven Ornstein‐Uhlenbeck processes
Authors: Abdelrazeq Ibrahim , Ivanoff B. Gail , Kulik Rafal
Published: March 2018

Lévy‐Driven Ornstein‐Uhlenbeck (or CAR(1)) processes have been introduced in the literature as a model for stochastic volatility. A general formula to recover the unobserved driving process from a continuously observed CAR(1) was developed. When the CAR(1) process is observed at discrete times, the driving process must be approximated. Approximated increments of the driving process are used to test the hypothesis that the CAR(1) belongs to a specified class of Lévy processes. Two goodness‐of‐fit tests are proposed. The performance of the tests is illustrated through simulation. The Canadian Journal of Statistics 46: 355–376; 2018 © 2018 Statistical Society of Canada
Laserinduzierte Fluoreszenz von Iod in der Gasphase
Authors: Dege Janina , Zeuch Thomas , Waitz Thomas
Published: March 2018

Die Fluoreszenz von Festkörpern und Flüssigkeiten ist ein weitläufig bekanntes Phänomen, das unter anderem auch im Alltag beobachtet werden kann. In diesem Versuch wird gezeigt, dass auch Stoffe in der Gasphase zu einer Fluoreszenz angeregt werden können – am Beispiel von gasförmigen Iod. Diese, durch grünes Laserlicht induzierte faszinierende Fluoreszenzentstehung sowie deren ‐löschung, können dabei anhand eines didaktisch angepassten Energiestufenmodell im fortgeschrittenen Chemieunterricht anschaulich erarbeitet werden. Darüber hinaus ermöglicht das Experiment viele Anknüpfungspunkte zu den grundlegenden Themen des Chemie‐ und Physikunterrichts wie Absorption, Emission, Strahlungs‐ sowie Energieübergänge
Efficient GPU‐based implementation for decoding non‐binary LDPC codes with layered and flooding schedules
Authors: Liu Zhanxian , Liu Rongke , Hou Yi , Peng Hao , Zhao Ling
Published: March 2018

Nonbinary low‐density parity‐check (NB‐LDPC) codes are excellent error correcting codes and outperform their binary counterparts under the same code length. NB‐LDPC decoders are based on Belief Propagation Algorithm, which demands intensive message‐passing computation. Recently, to achieve both flexibility and good throughput performance, NB‐LDPC decoders have been ported from dedicated hardware solutions to multi/many‐core systems. In this paper, we propose an FFT‐based q‐ary Sum‐Product Algorithm (QSPA) decoding architecture for NB‐LDPC codes with layered and flooding schedules on a graphics processing unit (GPU). To improve the throughput performance of the proposed decoder, four optimization methods are presented to not only accelerate the decoding kernel execution but also improve the data transfer efficiency. The experiments are mainly accomplished on NVIDIA GTX580 and GTX Titan X. Throughputs up to 63 Mbps over GF(16) and 7.65 Mbps over GF(256) are achieved on GTX580 when executing 5 layered decoding iterations. Throughputs can reach up to 139 Mbps over GF(16) and17 Mbps over GF(256) on GTX Titan X. Experimental results show that the speedups of the decoding throughputs range from ×1.7 to ×16.8 by comparison with the existing FFT‐based QSPA decoders on GPU.
Self‐learning and self‐adaptive resource allocation for cloud‐based software services
Authors: Chen Xing , Lin Junxin , Lin Bing , Xiang Tao , Zhang Ying , Huang Gang
Published: March 2018

In the presence of scale, dynamism, uncertainty, and elasticity, cloud engineers face several challenges when allocating resources for cloud‐based software services. They should allocate appropriate resources in order to guarantee good quality of services as well as low cost of resources. Self‐adaptive ability is needed in this process because engineers' intervention is difficult. Traditional self‐adaptive resource allocation methods are policy‐driven. Thus, cloud engineers usually have to develop separate sets of rules for each systems in order to allocate resources effectively, which leads to high administrative cost and implementation complexity. Machine learning has made great achievements in many fields, and it can be also applied to resource allocation. In this paper, we present a self‐learning and self‐adaptive approach to resource allocation for cloud‐based software services. For a given cloud‐based software service, its QoS model is firstly trained on history data, which is capable to predict the QoS value as output by using the information on workload and allocated resources as inputs. Then, on‐line decision‐making on resource allocation can be carried out automatically based on genetic algorithm, which is aimed to search reasonable resource allocation plan by using the QoS model. We evaluate our approach on RUBiS benchmark, demonstrating the accuracy of the QoS model over 90% and the improvement of resource utilization by 10%‐30%.
Investigating power capping toward energy‐efficient scientific applications
Authors: Haidar Azzam , Jagode Heike , Vaccaro Phil , YarKhan Asim , Tomov Stanimire , Dongarra Jack
Published: March 2018

The emergence of power efficiency as a primary constraint in processor and system design poses new challenges concerning power and energy awareness for numerical libraries and scientific applications. Power consumption also plays a major role in the design of data centers, which may house petascale or exascale‐level computing systems. At these extreme scales, understanding and improving the energy efficiency of numerical libraries and their related applications becomes a crucial part of the successful implementation and operation of the computing system. In this paper, we study and investigate the practice of controlling a compute system's power usage, and we explore how different power caps affect the performance of numerical algorithms with different computational intensities. Further, we determine the impact, in terms of performance and energy usage, that these caps have on a system running scientific applications. This analysis will enable us to characterize the types of algorithms that benefit most from these power management schemes. Our experiments are performed using a set of representative kernels and several popular scientific benchmarks. We quantify a number of power and performance measurements and draw observations and conclusions that can be viewed as a roadmap to achieving energy efficiency in the design and execution of scientific algorithms.