bluuebunny/crossref_metadata_2025 huggingface dataset:
ADAM9 contributes to vascular invasion in pancreatic ductal adenocarcinoma
Authors: Oria Victor O. , Lopatta Paul , Schmitz Tatjana , Preca Bogdan‐Tiberius , Nyström Alexander , Conrad Catharina , Bartsch Jörg W. , Kulemann Birte , Hoeppner Jens , Maurer Jochen , Bronsert Peter , Schilling Oliver
Published: December 2018

A disintegrin and a metalloprotease (ADAM)‐9 is a metzincin cell‐surface protease with strongly elevated expression in solid tumors, including pancreatic ductal adenocarcinoma (PDAC). In this study, we performed immunohistochemistry (IHC) of a tissue microarray (TMA) to examine the expression of ADAM9 in a cohort of >100 clinically annotated PDAC cases. We report that ADAM9 is prominently expressed by PDAC tumor cells, and increased ADAM9 expression levels correlate with poor tumor grading (P = 0.027) and the presence of vasculature invasion (P = 0.017). We employed gene expression silencing to generate a loss‐of‐function system for ADAM9 in two established PDAC cell lines. In vitro analysis showed that loss of ADAM9 does not impede cellular proliferation and invasiveness in basement membrane. However, ADAM9 plays a crucial role in mediating cell migration and adhesion to extracellular matrix substrates such as fibronectin, tenascin, and vitronectin. This effect appears to depend on its catalytic activity. In addition, ADAM9 facilitates anchorage‐independent growth. In AsPC1 cells, but not in MiaPaCa‐2 cells, we noted a pronounced yet heterogeneous impact of ADAM9 on the abundance of various integrins, a process that we characterized as post‐translational regulation. Sprout formation of human umbilical vein endothelial cells (HUVECs) is promoted by ADAM9, as examined by transfer of cancer cell conditioned medium; this finding further supports a pro‐angiogenic role of ADAM9 expressed by PDAC cancer cells. Immunoblotting analysis of cancer cell conditioned medium highlighted that ADAM9 regulates the levels of angiogenic factors, including shed heparin‐binding EGF‐like growth factor (HB‐EGF). Finally, we carried out orthotopic seeding of either wild‐type AsPC‐1 cells or AsPC‐1 cells with silenced ADAM9 expression into murine pancreas. In this in vivo setting, ADAM9 was also found to foster angiogenesis without an impact on tumor cell proliferation. In summary, our results characterize ADAM9 as an important regulator in PDAC tumor biology with a strong pro‐angiogenic impact.
Phenoptosis and the Evolution of Ageing
Authors: Walker Richard F
Published: December 2018

Phenoptosis describes ageing as the evolved product of a genome‐based program to limit lifespan and thereby favour evolution. Previously, programmed ageing was deemed incompatible with Darwinian dogma that population evolution depends upon genetic diversity resulting from selection of traits that provide individual benefit. To avoid this conflict, phenoptosis employs evolvability, an alternative theory of evolution through which biological systems can acquire novel functions that enhance population evolution without individual benefit. This article analyses the claim that ‘programmed’ ageing evolved de novo, specifically to limit lifespan exclusively under the cloak of evolvability, and if certain assumptions in phenoptosis theory are valid. A brief historic perspective of its origins will be followed by considerations of ‘when’, ‘why’ and ‘how’ it evolved. An alternative ‘programmatic’ theory that presents a mechanism for the coincidental evolution of ageing with the developmental program will be compared and contrasted with phenoptosis.

Key Concepts

Individual benefit is incompatible with phenoptosis (programmed ageing) theory, but compatible with development/ageing continuum (programmatic ageing) theory.

Immortal/nonageing animals preceded the evolution of phenoptosis.

Phenoptosis relies exclusively upon ‘evolvability’ to explain the evolution of ageing, yet ageing promotes ‘evolvability’ thereafter.

In nonsenescing populations (presumably existing before phenoptosis), evolution would be stifled by low adult death rate.

Natural selection in immortal populations causes unchecked birth rates, overpopulation and subsequent extinctions. Phenoptosis then emerges as an adaptation.

Phenoptosis evolved by the process of ‘supra‐individual’ selection.

Selection for ecological homeostasis counterbalances selection for expanding individual reproductive fitness and keeps growth rates in check.

Scheduled death increases individual turnover, provides more chances for evolution of diverse genotypes and thereby, increases evolvability.

Programmatic ageing is a product of coincidental evolution resulting from post‐maturational decay of the developmental program and of second‐order selection for population benefit.

Ageing is initiated and accelerated by progressive loss of temporal organisation within the whole organism, not by any individual or few factors affecting single metabolic or physiologic functions.
Sliding mode disturbance observer control based on adaptive synchronization in a class of fractional‐order chaotic systems
Authors: Mofid Omid , Mobayen Saleh , Khooban Mohammad‐Hassan
Published: December 2018

In this paper, a fractional‐order Dadras‐Momeni chaotic system in a class of three‐dimensional autonomous differential equations has been considered. Later, a design technique of adaptive sliding mode disturbance‐observer for synchronization of a fractional‐order Dadras‐Momeni chaotic system with time‐varying disturbances is presented. Applying the Lyapunov stability theory, the suggested control technique fulfils that the states of the fractional‐order master and slave chaotic systems are synchronized hastily. While the upper bounds of disturbances are unknown, an adaptive regulation scheme is advised to estimate them. The recommended disturbance‐observer realizes the convergence of the disturbance approximation error to the origin. Finally, simulation results are presented in one example to demonstrate the efficiency of the offered scheme on the fractional‐order Dadras‐Momeni chaotic system in the existence of external disturbances.
Monothiatruxene‐Based, Solution‐Processed Green, Sky‐Blue, and Deep‐Blue Organic Light‐Emitting Diodes with Efficiencies Beyond 5% Limit
Authors: Maciejczyk Michal R. , Zhang Shuyu , Hedley Gordon J. , Robertson Neil , Samuel Ifor D. W. , Pietraszkiewicz Marek
Published: December 2018

The development of blue materials with good efficiency, even at high brightness, with excellent color purity, simple processing, and high thermal stability assuring adequate device lifetime is an important remaining challenge for organic light‐emitting didoes (OLEDs) in displays and lightning applications. Furthermore, these various features are typically mutually exclusive in practice. Herein, four novel green and blue light‐emitting materials based on a monothiatruxene core are reported together with their photophysical and thermal properties, and performance in solution‐processed OLEDs. The materials show excellent thermal properties with high glass transition temperatures ranging from 171 to 336 °C and decomposition temperatures from 352 to 442 °C. High external quantum efficiencies of 3.7% for a deep‐blue emitter with CIE color co‐ordinates (0.16, 0.09) and 7% for green emitter with color co‐ordinates (0.22, 0.40) are achieved at 100 cd m−2. The efficiencies observed are exceptionally high for fluorescent materials with photoluminescence quantum yields of 24% and 62%, respectively. The performance at higher brightness is very good with only 38% and 17% efficiency roll‐offs at 1000 cd m−2. The results indicate that utilization of this unique molecular design is promising for efficient deep‐blue highly stable and soluble light‐emitting materials.
4D Biomaterials for Light‐Guided Angiogenesis
Authors: Farrukh Aleeza , Paez Julieta I. , del Campo Aránzazu
Published: December 2018

A strategy for spatial and temporal regulation of ligand presentation within a biomaterial, and the consequent site‐ and time‐specific cellular responses in 4D cell cultures are presented. The key molecular component is a light‐activatable adhesive peptidomimetic (cyclo Arg‐Gly‐Asp‐phe‐Cys, RGDfC) modified with the two‐photon photocleavable group (p‐methoxynitrobiphenyl, PMNB) used to functionalize a hydrogel. A scanning laser at 740 nm defines the 4D presentation of active RGD ligands within the gel, and directs basic cellular processes of embedded cells in situ. The excellent photochemical properties of the PMNB photoremovable group allows direct photomanipulation of the cellular environment without appreciable damage of the embedded cells. Light‐directed migration of fibroblasts within a crosslinked poly(ethylene glycol) (PEG) hydrogel, and sequential, light‐regulated angiogenesis with human umbilical vein endothelial cells (HUVECs) in 4D constructs is demonstrated. The materials presented here represent unique microenvironments to reconstruct dynamic changes in the composition of the extracellular space of cells that occur in in vivo tissues.
Study of the Interface of the Early Stages of Growth under Quasi‐Equilibrium Conditions of ZnO on Graphene/Cu and Graphite
Authors: Morales Carlos , Black Andrés , Urbanos Fernando J. , Granados Daniel , Méndez Javier , del Campo Adolfo , Yubero Francisco , Soriano Leonardo
Published: December 2018

The study of the early stages of growth of ZnO on graphene supported on Cu and on highly oriented pyrolytic graphite by means of reactive thermal evaporation of metallic Zn at room temperature is presented. This growth method allows to go in depth in the study of the fundamental interaction between ZnO and graphene at the interface in quasi‐equilibrium conditions. Quantitative, chemical, and morphological analysis is performed using photoemission spectroscopy, atomic force, and scanning microscopies as experimental characterization techniques and factor analysis and inelastic peak shape analysis as modeling techniques. The growth of ZnO on a highly oriented pyrolytic graphite substrate is also studied using the same growth method for comparison. The results show that, in spite that the first atomic layer of both substrates is identical, the growth kinetics and morphology of the deposits are completely different. A model for the kinetics of the growth of ZnO on both substrates is proposed.
Grafting Benzenediazonium Tetrafluoroborate onto LiNixCoyMnzO2 Materials Achieves Subzero‐Temperature High‐Capacity Lithium‐Ion Storage via a Diazonium Soft‐Chemistry Method
Authors: Sun Zhonghui , Li Zheng , Gao Lifang , Zhao Xin , Han Dongxue , Gan Shiyu , Guo Shaojun , Niu Li
Published: December 2018

Subzero‐temperature Li‐ion batteries (LIBs) are highly important for specific energy storage applications. Although the nickel‐rich layered lithium transition metal oxides(LiNixCoyMnzO2) (LNCM) (x > 0.5, x + y +z = 1) are promising cathode materials for LIBs, their very slow Li‐ion diffusion is a main hurdle on the way to achieve high‐performance subzero‐temperature LIBs. Here, a class of low‐temperature organic/inorganic hybrid cathode materials for LIBs, prepared by grafting a conducting polymer coating on the surface of 3 µm sized LiNi0.6Co0.2Mn0.2O2 (LNCM‐3) material particles via a greener diazonium soft‐chemistry method is reported. Specifically, LNCM‐3 particles are uniformly coated with a thin polyphenylene film via the spontaneous reaction between LNCM‐3 and C6H5N2+BF4−. Compared with the uncoated one, the polyphenylene‐coated LNCM‐3 (polyphenylene/LNCM‐3) has shown much improved low‐temperature discharge capacity (≈148 mAh g−1 at 0.1 C, −20 °C), outstanding rate capability (≈105 mAh g−1 at 1 C, −20 °C), and superior low‐temperature long‐term cycling stability (capacity retention is up to 90% at 0.5 C over 1150 cycles). The low‐temperature performance of polyphenylene/LNCM‐3 is the best among the reported state‐of‐the art cathode materials for LIBs. The present strategy opens up a new avenue to construct advanced cathode materials for wider range applications.
High Power Factors of Thermoelectric Colusites Cu26T2Ge6S32 (T = Cr, Mo, W): Toward Functionalization of the Conductive “Cu–S” Network
Authors: Pavan Kumar Ventrapati , Supka Andrew R. , Lemoine Pierric , Lebedev Oleg I. , Raveau Bernard , Suekuni Koichiro , Nassif Vivian , Al Rahal Al Orabi Rabih , Fornari Marco , Guilmeau Emmanuel
Published: December 2018

The introduction of hexavalent T6+ cations in p‐type thermoelectric colusites Cu26T2Ge6S32 (T = Cr, Mo, W) leads to the highest power factors among iono‐covalent sulfides, ranging from 1.17 mW m−1 K−2 at 700 K for W to a value of 1.94 mW m−1 K−2 for Cr. In Cu26Cr2Ge6S32, ZT reaches values close to unity at 700 K. The improvement of the transport properties in these new sulfides is explained on the basis of electronic structure and transport calculations keeping in mind that the relaxation time is significantly influenced by the size and the electronegativity of the interstitial T cation. The rationale is based on the concept of a conductive “Cu–S” network, which in colusites corresponds to the more symmetric parent structure sphalerite. A detailed structural analysis of these colusites shows that the distortion of the conductive network is influenced by the presence in the structure of mixed octahedral–tetrahedral [TS4]Cu6 complexes where the T cations are underbonded to sulfur and form metal–metal interactions with copper, Cu–T distances decreasing from 2.76 Å for W to 2.71 Å for Cr. The interactions between these complexes are responsible for the outstanding electronic transport properties. By contrast, the thermal conductivity is not significantly affected.
Assessment of physical fitness and its correlates in Chinese children and adolescents in Shanghai using the multistage 20‐M shuttle‐run test
Authors: Zou Zhichun , Chen Peijie , Yang Yang , Xiao Mouyuan , Wang Zhijie
Published: December 2018

Objective

The aim of this study was to evaluate the effectiveness of a multistage 20‐m shuttle‐run test (20‐m SRT) in assessing the physical fitness of Chinese children and adolescents in Shanghai.

Methods

A total of 4833 children and adolescents (2437 males and 2396 females, aged 7–17 years) were enrolled in this study. Height, weight, body fat percentage, fat‐free mass, BMI, and skinfold thickness were measured or calculated. The participants were randomly grouped for performing the 20‐m SRT. The maximal oxygen uptake (VO2max and VO2max/kg) was estimated from the 20‐m SRT using the model of Leger et al.

Results

All the measured and calculated parameters (age, height, weight, body fat percentage, fat‐free mass, BMI, skinfold thickness, and the results of the 20‐m SRT, as well as the estimated VO2max and VO2max/kg) had significant correlations with each other (P < .05). The multiple regression analyses indicated that (1) results of the 20‐m SRT were significantly associated with age, sex, height, and fat‐free mass (P < .05); (2) VO2max/kg was significantly associated with sex, age, weight, BMI, fat‐free mass, and skinfold thickness (P < .001); and (3) VO2max was markedly associated with sex, age, height, weight, BMI, fat‐free mass, and skinfold thickness (P < .001). There were differences between males and females in the results of multiple regression analyses.

Conclusions

Results of the 20‐m SRT and the estimated VO2max and VO2max/kg from the 20‐m SRT can be used for evaluating the physical fitness of children and adolescents in Shanghai. Gender may be a factor affecting the effectiveness of the 20‐m SRT.
Sex selection in late Iberian infant burials: Integrating evidence from morphological and genetic data
Authors: Afonso Cristina , Nociarova Dominika , Santos Cristina , Martinez‐Labarga Cristina , Mestres Imma , Duran Montserrat , Malgosa Assumpció
Published: December 2018

Objective

The aim of this study was to analyze the infant burials found inside Iberian homes in relation to a possible case of sex selection.

Methods

The study included the remains of 11 infant individuals buried under the 10 houses excavated in the late Iberian village of Camp de les Lloses (Tona, Barcelona, Spain). Sex was determined using genetic analysis.

Results

Our results showed that almost all the burials were females. However, the age interval of death was wide enough to weaken the premise of infanticide, and the burials probably represent cases of natural death.

Discussion

Infanticide in its different forms has long been argued as an explanation for the infant remains found throughout various burial sites. Many authors thought that infanticide, mainly femicide, was the main method of population control in ancient times. However, there is no anthropological evidence (age distribution and sex analyzed genetically) to support the intentional killing of females in this or in other cases. We hypothesized that there was a positive selection for females to be buried inside the houses, probably related to their benefactor roles.
A homozygous canonical splice acceptor site mutation in PRUNE1 is responsible for a rare childhood neurodegenerative disease in Manitoba Cree families
Authors: Hartley Jessica N. , Simard Louise R. , Ly Valentina , Del Bigio Marc R. , Frosk Patrick
Published: December 2018

Autosomal recessivePRUNE1mutations are reported to cause a severe neurodevelopmental disorder with microcephaly, hypotonia, and brain malformations. We describe clinical and neuropathological features in a cohort of nine individuals of Cree descent who, because of a founder effect, are homozygous for the samePRUNE1mutation. They follow the course of a combined neuromuscular and neurodegenerative disease, rather than a pure failure of normal development. This cohort presented in infancy with features of lower motor neuron disease, such as hypotonia, contractures, tongue fasciculations, and feeding difficulties in the absence of congenital brain anomalies and microcephaly. A neurodegenerative course followed with onset of seizures, spasticity, and respiratory insufficiency. Muscle biopsies showed denervation/reinnervation features, nonspecific atrophy and end‐stage atrophy. Autopsy findings in two patients are also described, suggesting length dependent central motor axon degeneration, peripheral motor axon degeneration, possible spinal motor neuron degeneration, and accumulation of beta amyloid precursor protein inclusions in select brainstem nuclei. Exome sequencing and homozygosity mapping identified a homozygousPRUNE1mutation in a canonical splice site, which produces two abnormalPRUNE1mRNA products. Based on our studies and the histopathology and phenotypic data, we provide further evidence that this disorder leads to a neurodegenerative disease affecting both the peripheral and central nervous systems and suggest that the pathogenic c.521‐2A>G mutation could lead to an altered effect on tubulin dynamics.
Visual processing in migraineurs depends on the migraine cycle
Authors: Luedtke Kerstin , Schulte Laura H. , May Arne
Published: December 2018

We investigated changes of after‐image duration in migraineurs and healthy controls (HCs) and throughout the migraine cycle to depict changes in the excitatory/inhibitory equilibrium within the visual cortex. Forty‐seven episodic (EMs) and 39 chronic migraineurs (CMs; interictal) were compared to 34 HCs for visual after‐image duration. Additionally, seven EMs were investigated every consecutive day over 20 to 32 days using the identical paradigm throughout the migraine cycle. Interictally, the after‐image duration was shorter compared to HCs, but significantly longer in the ictal compared to interictal phase. These data suggest an altered excitatory/inhibitory equilibrium in migraineurs, which oscillates over the migraine cycle. ANN NEUROL 2019;85:280–283.
Regulation of Protein Activity and Cellular Functions Mediated by Molecularly Evolved Nucleic Acids
Authors: Tan Jie , Zhao Mengmeng , Wang Jie , Li Zhihao , Liang Ling , Zhang Liqin , Yuan Quan , Tan Weihong
Published: December 2018

Regulation of protein activity is essential for revealing the molecular mechanisms of biological processes. DNA and RNA achieve many uniquely efficient functions, such as genetic expression and regulation. The chemical capability to synthesize artificial nucleotides can expand the chemical space of nucleic acid libraries and further increase the functional diversity of nucleic acids. Herein, a versatile method has been developed for modular expansion of the chemical space of nucleic acid libraries, thus enabling the generation of aptamers able to regulate protein activity. Specifically, an aptamer that targets integrin alpha3 was identified and this aptamer can inhibit cell adhesion and migration. Overall, this chemical‐design‐assisted in vitro selection approach enables the generation of functional nucleic acids for elucidating the molecular basis of biological activities and uncovering a novel basis for the rational design of new protein‐inhibitor pharmaceuticals.
Quantifying the Initial Unfolding of Bacteriorhodopsin Reveals Retinal Stabilization
Authors: Yu Hao , Heenan Patrick R. , Edwards Devin T. , Uyetake Lyle , Perkins Thomas T.
Published: December 2018

The forces that stabilize membrane proteins remain elusive to precise quantification. Particularly important, but poorly resolved, are the forces present during the initial unfolding of a membrane protein, where the most native set of interactions is present. A high‐precision, atomic force microscopy assay was developed to study the initial unfolding of bacteriorhodopsin. A rapid near‐equilibrium folding between the first three unfolding states was discovered, the two transitions corresponded to the unfolding of five and three amino acids, respectively, when using a cantilever optimized for 2 μs resolution. The third of these states was retinal‐stabilized and previously undetected, despite being the most mechanically stable state in the whole unfolding pathway, supporting 150 pN for more than 1 min. This ability to measure the dynamics of the initial unfolding of bacteriorhodopsin provides a platform for quantifying the energetics of membrane proteins under native‐like conditions.
Broadband Cr3+, Sn4+‐Doped Oxide Nanophosphors for Infrared Mini Light‐Emitting Diodes
Authors: Huang Wen‐Tse , Cheng Chiao‐Ling , Bao Zhen , Yang Chia‐Wei , Lu Kuang‐Mao , Kang Chieh‐Yu , Lin Chih‐Min , Liu Ru‐Shi
Published: December 2018

Light‐emitting diodes break barriers of size and performance for displays. With devices becoming smaller, the materials also need to get smaller. Chromium(III)‐doped oxide phosphors, which emit near‐infrared (NIR) light, have recently been used in small electronic devices. In this work, mesoporous silica nanoparticles were used as nanocarriers. The nanophosphor ZnGa2O4:Cr3+,Sn4+ formed in the mesopore after sintering. Good dispersity and morphology were performed with average diameters of 71±7 nm. It emitted light at 600–850 nm; the intensity was optimized by tuning the doping ratio of Cr3+ and Sn4+. Meanwhile, the light conversion efficiency increased from 7.8 % to 37 % and the molar concentration increased from 0.125 m to 0.5 m. The higher radiant flux of 3.3 mW was obtained by operating an input current of 45 mA. However, the NIR nanophosphor showed good performance on mini light‐emitting diode chips.
The Nature of Hydrogen Adsorption on Platinum in the Aqueous Phase
Authors: Yang Guoju , Akhade Sneha A. , Chen Xi , Liu Yue , Lee Mal‐Soon , Glezakou Vassiliki‐Alexandra , Rousseau Roger , Lercher Johannes A.
Published: December 2018

The thermodynamic state of H2 adsorbed on Pt in the aqueous phase was determined by kinetic analysis of H2 reacting with D2O to HDO, HD, and D2, and by DFT‐based ab initio molecular dynamics simulations of H2 adsorption on Pt(111), Pt(110), and Pt nanoparticles. Dissociative adsorption of H2 on Pt is significantly weakened in the aqueous phase compared to adsorption at gas–solid interfaces. Water destabilizes the adsorbed H atoms, decreasing the heat of adsorption by 19–22 kJ 
while inducing an additional entropy loss of 50–70 J 
 K−1. Upon dissociative adsorption of H2, the average distance of water from the Pt surface increases and the liquid adopts a structure that is more ordered than before close to the Pt surface, which limits the translation mobility of the adsorbed H atoms. The presence of hydrated hydronium ions next to the Pt surface further lowers the H−Pt bond strength.
Enabling PIEZOpotential in PIEZOelectric Semiconductors for Enhanced Catalytic Activities
Authors: Wang Mengye , Wang Biao , Huang Feng , Lin Zhiqun
Published: December 2018

The past several decades have witnessed significant advances in the synthesis and applications of PIEZOelectric semiconductors, an important class of materials, including piezoelectric, pyroelectric, and ferroelectric semiconductors. The intriguing combination of physical and chemical phenomena in PIEZOelectric semiconductors has triggered much interest in PIEZOcatalysis, that is, catalysis enabled by PIEZOpotential (i.e., piezopotential, pyropotential, and ferropotential)‐induced built‐in electric fields, which is the focus of this Minireview. First, the PIEZOelectric materials are briefly introduced. Second, recent developments in PIEZOcatalysis are highlighted, including the introduction of representative PIEZOelectric semiconductors, their possible catalytic mechanisms, novel techniques to produce their PIEZOelectric effects during the catalytic process, and several examples of PIEZOcatalysis. Finally, the challenges in the field and exciting opportunities to further improve the PIEZOcatalytic efficiency are discussed.
Catalytic Biomimetic Asymmetric Reduction of Alkenes and Imines Enabled by Chiral and Regenerable NAD(P)H Models
Authors: Wang Jie , Zhu Zhou‐Hao , Chen Mu‐Wang , Chen Qing‐An , Zhou Yong‐Gui
Published: December 2018

The development of biomimetic chemistry based on the NAD(P)H with hydrogen gas as terminal reductant is a long‐standing challenge. Through rational design of the chiral and regenerable NAD(P)H analogues based on planar‐chiral ferrocene, a biomimetic asymmetric reduction has been realized using bench‐stable Lewis acids as transfer catalysts. A broad set of alkenes and imines could be reduced with up to 98 % yield and 98 % ee, likely enabled by enzyme‐like cooperative bifunctional activation. This reaction represents the first general biomimetic asymmetric reduction (BMAR) process enabled by chiral and regenerable NAD(P)H analogues. This concept demonstrates catalytic utility of a chiral coenzyme NAD(P)H in asymmetric catalysis.
Azo‐MICs: Redox‐Active Mesoionic Carbene Ligands Derived from Azoimidazolium Dyes
Authors: Chadwick F. Mark , Curchod Basile F. E. , Scopelliti Rosario , Fadaei Tirani Farzaneh , Solari Euro , Severin Kay
Published: December 2018

Azoimidazolium dyes were used as precursors for mesoionic carbene ligands (Azo‐MICs). The properties of these ligands were examined by synthesizing RhI, AuI, and PdII complexes. Experimental (NMR, IR) and theoretical investigations show that Azo‐MICs are potent σ‐donor ligands. Yet, they feature a small singlet–triplet gap and very low‐lying LUMO levels. The unique electronic properties of Azo‐MICs allow for reversible one‐electron reductions of the metal complexes, as evidenced by cyclic voltammetry.
Transformation of Imine Cages into Hydrocarbon Cages
Authors: Schick Tobias H. G. , Lauer Jochen C. , Rominger Frank , Mastalerz Michael
Published: December 2018

In contrast to organic cages which are formed by exploiting dynamic covalent chemistry, such as boronic ester cages, imine cages, or disulfide cages, those with a fully carbonaceous backbone are rarer. With the exception of alkyne metathesis based approaches, the vast majority of hydrocarbon cages need to be synthesized by kinetically controlled bond formation. This strategy implies a multiple step synthesis and no correction mechanism in the final macrocyclization step, both of which are responsible for low overall yields. Whereas for smaller cages the intrinsic drawbacks are not always obvious, larger cages are seldom synthesized in yields beyond a few tenths of a percent. Presented herein is a three‐step method to convert imine cages into hydrocarbon cages. The method has been successfully applied to even larger structures such as derivatives of C72H72 , an unknown cage suggested by Fritz Vögtle more than 20 years ago.
Polystyrene bioactive nanofibers using orange oil as an ecofriendly solvent
Authors: Miranda Kelvi W. E. , Mattoso Luiz H. C. , Bresolin Joana D. , Hubinger Silviane Z. , Medeiros Eliton S. , de Oliveira Juliano E.
Published: December 2018

Solution blow spun polystyrene (PS) nanofibers were produced from 20 to 30 wt % PS solutions using toluene (industrial solvent) and orange oil (green solvent). The latter being composed of d‐limonene (97.06%) as determined by gas chromatography–mass spectroscopy. The rheological behavior and volatility of the solvents and polymer solutions were correlated with fiber morphology, accessed by scanning electron microscopy. Thermal analysis was used to determine the thermal behavior of fibers. The antimicrobial activity of orange oil was tested for potential applications of the spun mats in active food packaging. Results showed that the nanofibers spun from orange oil solutions had average diameters of 306 ± 74 nm as opposed to 441 ± 110 nm for toluene. Moreover, when compared with fiber spun from toluene solutions, orange oil yielded more flexible fibers with slightly lower contact angles and better antimicrobial properties due to the presence of residual oil confirmed by Fourier‐transform infrared spectroscopy. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47337.
Effect of solvent quality on Poiseuille flow of polymer solutions in microchannels: A dissipative particle dynamics study
Authors: Xu Shaofeng , Lou Yinghou , He Ping , Wang Xiangyang , Wang Jiugen
Published: December 2018

The Poiseuille flows of polymer solutions for varying quality solvents in microchannels have been simulated using dissipative particle dynamics. In particular, the velocity distributions and the polymer migration across the channel have been investigated for good, athermal, and poor solvents. The velocity profiles for all three kinds of solvent deviate from the parabolic profile, and the velocity profile of the athermal solvent falls in between the good solvent and the poor solvent. For the athermal solvent, a migration away from the wall due to the hydrodynamic interactions between the chains and the wall is observed, and a migration away from the channel center due to the different chain Brownian diffusivities is also observed. For the good solvent, because of the more stretched polymer chains, the migration away from the wall is stronger than that for the athermal solvent. However, the migration away from the channel center is not observed for good solvents. For the poor solvent, the hydrodynamic interaction within the chains is screened, and the polymer chains migrate toward the wall and appear to be absorbed by the wall. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2019,136, 47345.
Assessing conservation priorities of endemic freshwater fishes in the Tropical Andes region
Authors: Tognelli Marcelo F. , Anderson Elizabeth P. , Jiménez‐Segura Luz F. , Chuctaya Junior , Chocano Luisa , Maldonado‐Ocampo Javier A. , Mesa‐Salazar Lina , Mojica José I. , Carvajal‐Vallejos Fernando M. , Correa Vanessa , Ortega Hernán , Rivadeneira Romero Juan F. , Sánchez‐Duarte Paula , Cox Neil A. , Hidalgo Max , Jiménez Prado Pedro , Lasso Carlos A. , Sarmiento Jaime , Velásquez Miguel A. , Villa‐Navarro Francisco A.
Published: December 2018

Assessing the effectiveness of protected areas for sustaining species and identifying priority sites for their conservation is vital for decision making, particularly for freshwater fishes in South America, the global centre of freshwater fish diversity. Several conservation planning studies have used threatened freshwater fishes or species that are vulnerable to climate change as conservation targets, but none has included both in priority‐setting analysis.

The objectives of this study were to identify gaps in the coverage of the existing protected areas in representing the endemic freshwater fishes of the Tropical Andes region, and to identify conservation priority areas that adequately cover threatened species and species vulnerable to climate change.

Data on 648 freshwater fishes from the Tropical Andes were used to identify gaps in the protected area coverage, and to identify conservation priority sites under three scenarios: (i) prioritize threatened species; (ii) prioritize species that are vulnerable to climate change; and (iii) prioritize both threatened species and species vulnerable to climate change.

A total of 571 species (88% of all species) were not covered by any protected areas; most of them are restricted to ≤10 catchments. To represent both threatened species and species vulnerable to climate change in the third scenario, 635 catchments were identified as priority areas, representing 26.5% of the study area. The number of irreplaceable catchments for this scenario is 475, corresponding to 22.5% of the total area.

The results of this study could be crucial for designing strategies for the effective protection of native fish populations in the Tropical Andes, and for planning proactive climate adaptation. It is hoped that the identification of priority areas, particularly irreplaceable catchments, will help to guide conservation and management decisions in the Andean region.
Restricted movement of prairie fishes in fragmented riverscapes risks ecosystem structure being ratcheted downstream
Authors: Schumann David A. , Haag Jenna M. , Ellensohn Paige C. , Redmond Jordon D. , Graeb Katie N.B.
Published: December 2018

Prairie streams are dynamic systems in which habitat patches are sporadically created and lost during extreme hydrological events. The persistence of fish species depends on life‐history traits that facilitate their widespread dispersal to recolonize habitats after stochastic extirpation. Artificial barriers are thought to reduce recolonization opportunities and to ultimately displace populations downstream, but the ecological consequences of lost diversity above the barriers are largely unknown.

The susceptibility of four prairie fishes to fragmentation and the consequent risk to stream ecosystem processes are described. The selected species exhibit wide tolerances to environmental stressors, represent unique functional feeding guilds, and have different habitat affinities.

The ability of each species to access (jumping ability) and successfully traverse (swimming endurance) simulated instream barriers was quantified in the laboratory. Experimental stream complexes were used to isolate the effects of these species on ecosystem structure and function. These replicated single‐species experiments were compared with ‘no fish’ controls to identify the ecological role of each.

Small vertical barriers blocked most passage, and with open access all species were unable to traverse relatively short distances against modest water velocities. Stream fragmentation will alter headwater fish assemblage structure and promote the most mobile species. Each species had slightly different effects on the stream ecosystem structure resulting from their different habitat preferences and diets.

Without colonization opportunities from neighbouring populations, disturbance events will alter headwater fish assemblages and may degrade the ecosystem structure above barriers.

Fragmented riverscapes interact with harsh disturbance regimes to form an ecological ratchet. Systematic species loss above barriers outweighs the opportunity for improvement, suggesting that ecosystem structure may be moving downstream.
Selective Fluorescence Turn‐On Sensing of Phosphate Anion in Water by Tetraphenylethylene Dimethylformamidine
Authors: Yuan Ying‐Xue , Wang Jin‐Hua , Zheng Yan‐Song
Published: December 2018

A tetraphenylethylene (TPE) derivative bearing two dimethylformamidine units was synthesized. The dihydrogen chloride salt of this TPE derivative was soluble in water and showed almost no emission. By addition of phosphate anions, the dihydrogen chloride salt could be transformed into the monohydrogen chloride salt, which was barely soluble and emitted strong fluorescence through aggregation‐induced emission (AIE), while many other anions could not bring about a fluorescence enhancement. Meanwhile, the dihydrogen chloride salt and monohydrogen chloride salt could be reversible transformed by addition of acid and base alternately in the presence of phosphate anion, which led to fluorescence turn‐on and turn‐off. Therefore, the TPE dimethylformamidine holds potential for selectively sensing phosphate anions in water and use as fluorescence pH switch. This study provided a new approach to AIEgen sensors by using formamidine groups.
Molecular Links and Knots from Naphthalenediimide: A Balance of Weak Interactions
Authors: Ng Antony Wing Hung , Au‐Yeung Ho Yu
Published: December 2018

Owing to its unique structural, electronic, spectroscopic, and redox properties, naphthalenediimide (NDI) is a versatile building block for the construction of a wide variety of supramolecular assemblies with diverse structures, properties, and functions. In this Minireview, the synthesis of topologically nontrivial molecular links and knots based on naphthalenediimide‐derived building blocks will be discussed. In particular, the supramolecular forces that contribute to the formation of these molecular links and knots and their interactions will be discussed.
Multiple‐model sliding mode observer for an artificial gas lift system
Authors: Hammadih Mohammad Luai , Al Hosani Khalifa , Boiko Igor
Published: December 2018

Artificial gas lift is widely used in the oil industry to enhance oil recovery. Active feedback control of this process would lead to its stabilization, that in some operating modes may otherwise be unstable, and to the increase of oil production. However, the control strategies are normally constrained to the use of the surface‐measured process variables. The use of down‐hole measurements would improve the performance of the control system but is technically hardly feasible due to the necessity of placing instruments in harsh conditions. The use of state observation might be a feasible alternative to the down‐hole measurements. Recent development of a new accurate model of the artificial gas lift process enables us to increase accuracy of observation due to the account of pressure and density distribution along the well depth. Besides, a new approach to a nonlinear model treatment proposed in the present paper leads to a high computational efficiency of the observer for the gas lift. The paper presents an approach to the design of a novel sliding mode observer for the gas lift process. The observer uses multiple linearized models representing deviations from a set of equilibrium points. These models are then incorporated to produce estimates for the gas lift process variables. The approach is supported by simulations.
Backstepping control of flexible joint manipulator based on hyperbolic tangent function with control input and rate constraints
Authors: Wang Lijun , Shi Qiuyue , Liu Jinkun , Zhang Dan
Published: December 2018

In this paper, we investigate the trajectory tracking problems of the link angle and angle speed of the flexible joint manipulator model based on external disturbance, the control input and rate constraints. The controller of the flexible joint manipulator model is designed using the backstepping control scheme. To achieve this objective, the smooth hyperbolic tangent function is used to solve the problems of control input and rate constraints, and the stability is proved using Lyapunov function in the design procedure of the backstepping control scheme. Finally, the effectiveness of the proposed backstepping controller is verified by numerical simulation.
Females who maltreat animals
Authors: Felthous Alan R. , Calhoun Amanda J.
Published: December 2018

Studies of animal maltreatment and of untoward or abnormal aggression predominantly involve male subjects, raising the question as to whether females who engage in such behaviors are like, or fundamentally different than, their male counterparts. Inquiry to address this issue could pertain to gender similarities and differences; moreover, it could provide greater understanding of the behavior itself, in this case, animal maltreatment. Of the various patterns of animal maltreatment in the literature, there are enough studies with gender addressed to allow some observations on two patterns: animal cruelty in childhood and animal hoarding. Animal cruelty among girls may be more common than is widely assumed, but substantial recurrent cruelty appears, as expected, to be more common among males and is consistent with conduct disorder occurring more frequently among boys. Females, especially older females who live alone, predominate among animal hoarders, whose psychology is altogether different from those who engage in antisocial cruelty. The potential significance of these observations is discussed within the contexts of developmental and gender psychology.
Direct C−H Carbamoylation of Nitrogen‐Containing Heterocycles
Authors: Jouffroy Matthieu , Kong Jongrock
Published: December 2018

Nucleophilic radical additions at innately electrophilic C(sp2) centers are perfectly suited for the direct functionalization of heterocycles. Using bench stable and commercially available alkyl oxamate and oxamic acid derivatives in combination with photoredox catalysis, a direct carbamoylation of heterocycles yielding amide functionalized pharmacophores in a single step is reported. The reaction conditions reported are compatible with structurally complex heterocyclic substrates of pharmaceutical interest. Notably, derivatives containing functional groups incompatible with standard amidation reactions, such as carboxylic acids and unprotected amines, were found to be amenable to this reaction paradigm.
Risk of solid subsequent malignant neoplasms after childhood Hodgkin lymphoma—Identification of high‐risk populations to guide surveillance: A report from the Late Effects Study Group
Authors: Holmqvist Anna S. , Chen Yanjun , Berano Teh Jennifer , Sun Canlan , Birch Jillian M. , van den Bos Cor , Diller Lisa R. , Dilley Kimberley , Ginsberg Jill , Martin Laura T. , Nagarajan Rajaram , Nathan Paul C. , Neglia Joseph P. , Terenziani Monica , Tishler David , Meadows Anna T. , Robison Leslie L. , Oberlin Odile , Bhatia Smita
Published: December 2018

Background

Survivors of Hodgkin lymphoma (HL) in childhood have an increased risk of subsequent malignant neoplasms (SMNs). Herein, the authors extended the follow‐up of a previously reported Late Effects Study Group cohort and identified patients at highest risk for SMNs to create evidence for risk‐based screening recommendations.

Methods

The standardized incidence ratio was calculated using rates from the Surveillance, Epidemiology, and End Results program as a reference. The risk of SMN was estimated using proportional subdistribution hazards regression. The cohort included 1136 patients who were diagnosed with HL before age 17 years between 1955 and 1986. The median length of follow‐up was 26.6 years.

Results

In 162 patients, a total of 196 solid SMNs (sSMNs) were identified. Compared with the general population, the cohort was found to be at a 14‐fold increased risk of developing an sSMN (95% confidence interval, 12.0‐fold to 16.3‐fold). The cumulative incidence of any sSMN was 26.4% at 40 years after a diagnosis of HL. Risk factors for breast cancer among females were an HL diagnosis between ages 10 years and 16 years and receipt of chest radiotherapy. Males treated with chest radiotherapy at age <10 years were found to be at highest risk of developing lung cancer. Survivors of HL who were treated with abdominal/pelvic radiotherapy and high‐dose alkylating agents were found to be at highest risk of developing colorectal cancer and females exposed to neck radiotherapy at age <10 years were at highest risk of thyroid cancer. By age 50 years, the cumulative incidence of breast, lung, colorectal, and thyroid cancer was 45.3%, 4.2%, 9.5%, and 17.3%, respectively, among those at highest risk.

Conclusions

Survivors of childhood HL remain at an increased risk of developing sSMNs. In the current study, subgroups of survivors of HL at highest risk of specific sSMNs were identified, and evidence for screening provided.
Beer's Law – Why Absorbance Depends (Almost) Linearly on Concentration
Authors: Mayerhöfer Thomas G. , Popp Jürgen
Published: December 2018

Beer's law assumes a strictly linear dependence of the absorbance from concentration. Usually, chemical interactions and instrumental imperfection are made responsible for experimental deviations from this linearity. In this contribution we show that even in the absence of such interactions and instrumental errors, absorbance should be only approximately proportional to concentration. This can be derived from the quadratic dependence of the complex refractive index, and, by that, of the molar attenuation coefficient, from the dielectric constant and its frequency dispersion. Following dispersion theory, it is the variation of the real and the imaginary part of the dielectric function that depends linearly on concentration in the absence of interactions between the oscillators. We show that this linear correlation translates into a linear dependence of the absorbance for low concentrations or molar oscillator strengths based on an approximation provided by Lorentz in 1906. Accordingly, Beer's law can be derived from dispersion theory.
Green Hydrogen Separation from Nitrogen by Mixed‐Matrix Membranes Consisting of Nanosized Sodalite Crystals
Authors: Yang Ge , Guo Hailing , Kang Zixi , Zhao Lei , Feng Shou , Jiao Feng , Mintova Svetlana
Published: December 2018

Nanosized sodalite (Nano‐SOD) crystals were used as active filler to prepare mixed‐matrix membranes (MMMs) for promoting the H2/N2 gas‐separation performance. The Nano‐SOD crystals with extremely small crystallites (40–50 nm) were synthesized from a colloidal suspension free of organic structural directing agent and uniformly dispersed in the polyetherimide (PEI) matrix. The Nano‐SOD filler with a suitable aperture size (2.8 Å) allowed only H2 molecules to pass through and rejected the N2, thus improving the selectivity of the membranes. The high dispersion of Nano‐SOD crystals in the polymer matrix and the interactions between the inorganic and organic phases greatly improved the membrane separation performance and minimized interfacial holes. The MMMs showed a high H2 permeability (≈7155.1 Barrer at 25 °C under atmospheric pressure) and an ideal H2/N2 selectivity factor of approximately 16.9 in a single gas test. Moreover, in a gas mixture (H2/N2, 25–100 °C), the selectivity factor increased significantly to approximately 30.9. The high stability of the MMMs, which consist of highly dispersed Nano‐SOD crystals in a PEI matrix for H2/N2 separation (6 weeks continuous test), makes them an important material for ammonia synthesis applications that require and also release a large amount of H2.