bluuebunny/crossref_metadata_2025 huggingface dataset:
Visible Light Photocatalysis of Radical Cation Diels–Alder Cycloadditions: Preparation of Tris(2,2’‐bipyrazyl) Ruthenium(II) Bis(tetrakis(3,5‐bis(trifluoromethyl)phenyl)borate)
Authors: Lies Shane D. , Lin Shishi , Yoon* Tehshik P.
Published: March 2017

The article describes visible light photocatalysis of radical cation Diels–Alder cycloadditions. The electron‐deficient bipyrazyl ligands render this photocatalyst a substantially more powerful photooxidant than the more common parent tris(bipyridyl) complex. Due to the attractive photoredox properties of Ru(bpz)3 2+ coupled with its chemical stability and long excited state lifetime, this photocatalyst has proven to be powerfully enabling in a variety of photooxidative transformations. These have included oxidative [3+2] cycloadditions of phenols, thiol–ene reactions, and aerobic cyclooxygenation reactions, among others. However, previously reported methods for the synthesis of the bipyrazyl ligand are not easily scalable or provide poor yields. The improved method described in this manuscript is based upon optimized conditions reported recently by our group.
Preparation of 1,5‐Dioxaspiro[5.5]undecan‐3‐one
Authors: Craig Robert A. , Smith Russell C. , Pritchett Beau P. , Estipona Benzi I. , Stoltz* Brian M.
Published: March 2017

The article describes the preparation of 1,5‐Dioxaspiro[5.5]undecan‐3‐one. Synthesis of the analogous diethyl ketal product has been accomplished using 3,3‐dimethoxypentane in place of 1,1‐dimethoxycyclohexane. The utility of ketodioxanones as nucleophiles in enantioselective palladium‐catalyzed allylic alkylations, diastereoselective alkylations, α,α’‐annulations, and organocatalyic stereoselective aldol condensations. The products of these transformations have been successfully applied to the synthesis of a variety of simple and complex carbohydrates and biologically active natural products.
Synthesis of 1‐Iodopropyne
Authors: Bartko Samuel G. , Deng James , Danheiser Rick L.
Published: March 2017

The article discusses the synthesis of 1‐iodopropyne. Number of reports describe the application of 1‐iodopropyne as a useful synthetic building block and as an intermediate in total syntheses of acetylenic natural products.
Potassium
tert
‐Butoxide–Catalyzed Dehydrogenative Cross‐Coupling of Heteroarenes with Hydrosilanes
Authors: Toutov Anton A. , Liu Wen‐Bo , Stoltz* Brian M. , Grubbs* Robert H.
Published: March 2017

Heteroarylsilanes are valuable synthetic intermediates which are widely used in complex molecules synthesis, medicinal chemistry and drug discovery, and advanced materials and polymers synthesis. The article describes the method for dehydrogenative cross‐coupling reaction using potassium tert‐butoxide as a catalyst that provides a unique way to access a wide array of heteroarylsilanes. The procedure reported here is applicable to a range of heteroarenes and hydrosilanes, giving access to synthetically valuable heteroarylsilanes on multigram scales.
Synthesis of α‐Carboline
Authors: He Linli , Allwein Shawn P. , Dugan Benjamin J. , Knouse Kyle W. , Ott Gregory R. , Zificsak* Craig A.
Published: March 2017

The article reports synthesis of α‐Carboline. This heterocycle has found utility as a building block in natural product and medicinal chemistry as well as in optoelectronic materials. Literature procedures for the preparation of 2 fall into two general catagories: thermolysis of a pyridylbenzotriazole, with extrusion of nitrogen leading to bond formation (a modified Graebe‐Ullman reaction) or formation of the C4a‐C4b bond from an aryl halide–aryl‐H intramolecular coupling.
Nickel‐Catalyzed Suzuki–Miyaura Coupling int‐Amyl Alcohol for the Preparation of 5‐(Furan‐3‐yl)pyrimidine
Authors: Hie Liana , Garg* Neil K.
Published: March 2017

Transition metal‐catalyzed cross‐couplings are versatile methods for carbon–carbon and carbon–heteroatom bond formation. Traditionally, palladium catalysts have been most commonly utilized for this type of transformation; however, there has been a significant interest in the development of cross‐coupling reactions that rely on non‐precious metal catalysts. In particular, nickel has emerged as an alternative to palladium due to several factors. The article reports nickel‐catalyzed Suzuki–Miyaura coupling int‐amyl alcohol for the preparation of 5‐(Furan‐3‐yl)pyrimidine.
Preparation of (S)‐Nonafluorobutanesulfinamide
Authors: Wangweerawong Apiwat , Kolmar Scott , Ellman* Jonathan A.
Published: March 2017

The article reports preparation of (S)‐Nonafluorobutanesulfinamide. For the preparation of the perfluorobutanesulfinamide, we focused on Senanayake's chiral sulfinyl transfer auxiliary approach. The two‐step synthesis of perfluorobutanesulfinamide from Senanayakes's 2‐aminoindanol‐derived sulfinyl transfer reagent described in this report proceeds in good overall yield and with excellent enantiomeric purity. The described method uses inexpensive nonafluoro‐1‐iodobutane as a starting input and requires only one straightforward flash column chromatography. Additionally, the chiral auxiliary 3 can be recovered in good yields.
Preparation of 1‐methylimidazole‐N‐oxide (NMI‐O)
Authors: Murray James I. , Spivey* Alan C.
Published: March 2017

The article describes the preparation of 1‐methylimidazole‐N‐oxide.N‐heterocycles were generally more efficient than theirN‐oxide analogues in the acylation process,N‐oxides were generally more active for the sulfonylation and silylation of alcohol derivatives. In particular, 1‐methylimidazole‐N‐oxide (NMI‐O) was found to be a highly efficient catalyst both for sulfonylation and silylation. NMI‐O was found to be the only amine orN‐oxide Lewis basic organocatalyst capable of promoting the efficient silylation of tertiary alcohol derivatives with low catalyst loading (2.5 mol%) and under mild reaction conditions.
Preparation of 1,1‐Difluoroallenes by Difluorovinylidenation of Carbonyl Compounds
Authors: Fuchibe Kohei , Abe Masashi , Oh Ken , Ichikawa* Junji
Published: March 2017

The article reports the preparation of 1,1‐difluoroallenes by difluorovinylidenation of carbonyl cmpounds. 1,1‐Difluoroallenes have been synthesized via either the formation of the second C–C double bond in fluorinated alkenes or the rearrangement of the C–C triple bonds in fluorinated alkynes.
Synthesis of Cyclobutanes by Lewis Acid‐Promoted Ketene‐Alkene [2+2] Cycloadditions
Authors: Rasik Christopher M. , Salyers Eleni M. , Brown* M. Kevin
Published: March 2017

When compared to thermally‐induced reactions, Lewis acid‐promoted variants give rise to increased yields for unactivated alkenes. The article describes the synthesis of cyclobutanes by Lewis acid‐promoted ketene‐alkene [2+2] cycloadditions.
Asymmetric Synthesis of 2‐Thiocyanato‐2‐(1‐aminoalkyl)‐substituted 1‐Tetralones and 1‐Indanones with Tetrasubstituted Carbon Stereogenic Centers via Cooperative Cation‐Binding Catalysis
Authors: Yu Lei , Wu Xiaoyan , Kim Mun Jong , Vaithiyanathan Venkataramasubramanian , Liu Yidong , Tan Yu , Qin WenLing , Song Choong Eui , Yan Hailong
Published: March 2017

In this study, the concept of cooperative cation‐binding catalysis was applied for direct generation of two contiguous trisubstituted and tetrasubstituted stereogenic centers. Using the readily accessible chiral oligoethylene glycol (oligoEG) as a cation‐binding catalyst, asymmetric Mannich reactions of α‐thiocyanato cyclic ketones as Mannich donors were performed with α‐amidosulfones as the bench‐stable imine precursors in the presence of potassium fluoride as the base, affording 2‐thiocyanato‐2‐(1‐aminoalkyl)‐substituted 1‐tetralones and 1‐indanones possessing fully substituted C–SCN centers. The salient features of this process include (i) a transition metal‐free and operationally simple procedure, (ii) direct use of α‐amidosulfones as bench‐stable precursors of sensitive imines, (iii) direct enolization of racemic cyclic α‐thiocyanato ketones and (iv) excellent stereoselectivity with up to 99% ee and >20:1 diastereoselectivity (anti:syn). This protocol is easily scalable and provides a new approach for the syntheses of some biologically relevant products possessing fully substituted C–SCN centers.

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Reproductive status affects the feeding ecology and social association patterns of female squirrel monkeys (Saimiri collinsi) in an Amazonian rainforest
Authors: Ruivo Luana V.P. , Stone Anita I. , Fienup Matthew
Published: March 2017

When making foraging decisions, female primates may follow specific behavioral strategies that reflect their reproductive state. Lactation is considered the most energetically costly phase for females, but we argue that gestation is also energetically expensive for squirrel monkeys. In this study, we examined whether female squirrel monkeys (a seasonally breeding primate) in different reproductive phases showed significant differences in their foraging ecology. We sampled two wild groups of squirrel monkeys (Saimiri collinsi) using the focal animal method, during 12 months (June 2014 to May 2015). During this time, we quantified the effect of reproductive state (mating, gestation, and lactation) and sex (females vs. males) on activity budgets, foraging efficiency, dietary composition, and nearest neighbors. We found significant effects of both sex and reproductive phase on the mean proportion of time spent foraging, resting, traveling, and being social. Females consumed more insects than did males at all times; among females, time spent eating prey and fruit varied according to reproductive state. These data suggest that, due to their life history and seasonal breeding, reproduction is a costly activity for female Saimiri, and not only during lactation. Therefore, adopting the appropriate behavioral strategies is essential to reduce energetic deficits in females.
How far do Neotropical primates disperse seeds?
Authors: Fuzessy Lisieux F. , Janson Charles H. , Silveira Fernando A. O.
Published: March 2017

Seed dispersal distance (SDD) is a vital component of vertebrate‐mediated seed dispersal process: the average distance at which seeds are deposited away from the parent plant represents the starting template of plant regeneration. We present a simple model to explain and predict observed measures of average dispersal distance and we hypothesize that it is a consequence of how long seeds are retained in the disperser's gut, how rapidly the disperser moves per unit time and how twisted the animal travel path is relative to the straight‐line distance moved away from the seed source. We retrieved data on dispersal distances from 26 published studies including nine primate species dispersing up to 112 plant species per study. We used gut transit time (TT) as a proxy for residence time inside the gut, the disperser's travel path per hour as proxy for movement rate, and the daily path length relative to the home range area as a correlate of path twisting (PT). We illustrate this model with comparative data on Neotropical primates. These three variables explained 90% of the variation in the average SDD. Path analysis indicates that additional variables exerted only indirect effects. Our model can be applied to primate populations for which detailed seed dispersal data are missing, and help evaluate conservation priorities for primate species according to the potential service they provide in terms of forest regeneration.
Shifting diet, shifting culture? A bioarchaeological approach to island dietary development on Iron‐Age Öland, Baltic Sea
Authors: Wilhelmson Helene
Published: March 2017

Objectives

The diet and subsistence in Iron‐Age Öland is debated as earlier studies and different archaeological sources seemingly provide conflicting interpretations. The objectives of this study are therefore to: (i) add new insights on diet and (ii) investigate the chronological variation in detail. It is common in studies of diet to investigate differences between datasets defined by archaeological periods (determined by artefact typology), but it is rare to explore whether these dietary changes are, in fact, well correlated with these temporal categories or not.

Materials and methods

Stable isotope analysis of 108 individuals and 25 animals was used to interpret diet in comparison with data from earlier studies. Different values of TLE (Trophic Level Effect) for δ15N were compared for interpretations of diet. Of the 108 individuals, 42 were subjected to 14C analysis in this study.

Results

The isotopes from Iron‐Age animals on Öland indicate that the local, contemporary ecology is specific. The human isotope values show chronological development both when pooled in chronological groups by typology and by more specific 14C chronology.

Discussion

The new samples of animals as well as the use of 5‰ TLE for δ15N values results in the diet reinterpreted as mainly domesticate‐based, with at least two shifts in diet occurring in the Iron Age. The use of 14C dates in connection with the stable isotope results indicates a dietary transition occurring between 200 BC and AD 200, a date range that spans two typologically determined time periods.
Quantification of the position and depth of theflexor hallucis longusgroove in euarchontans, with implications for the evolution of primate positional behavior
Authors: Yapuncich Gabriel S. , Seiffert Erik R. , Boyer Doug M.
Published: March 2017

Objective

On the talus, the position and depth of the groove for theflexor hallucis longustendon have been used to infer phylogenetic affinities and positional behaviors of fossil primates. This study quantifies aspects of theflexor hallucis longusgroove (FHLG) to test if: (1) a lateral FHLG is a derived strepsirrhine feature, (2) a lateral FHLG reflects inverted and abducted foot postures, and (3) a deeper FHLG indicates a larger muscle.

Methods

We used linear measurements of microCT‐generated models from a sample of euarchontans (n = 378 specimens, 125 species) to quantify FHLG position and depth. Data are analyzed with ANOVA, Ordinary and Phylogenetic Generalized Least Squares, and Bayesian Ancestral State Reconstruction (ASR).

Results

Extant strepsirrhines, adapiforms, plesiadapiforms, dermopterans, andPtilocercusexhibit lateral FHLGs. Extant anthropoids, subfossil lemurs, andTupaiahave medial FHLGs. FHLGs of omomyiforms and basal fossil anthropoids are intermediate between those of strepsirrhines and extant anthropoids. FHLG position has few correlations with pedal inversion features. Relative FHLG depth is not significantly correlated with body mass. ASRs support a directional model for FHLG position and a random walk model for FHLG depth.

Conclusions

The prevalence of lateral FHLGs in many non‐euprimates suggests a lateral FHLG is not a derived strepsirrhine feature. The lack of correlations with pedal inversion features suggests a lateral FHLG is not a sufficient indicator of strepsirrhine‐like foot postures. Instead, a lateral FHLG may reduce the risk of tendon displacement in abducted foot postures on large diameter supports. A deep FHLG does not indicate a larger muscle, but likely reduces bowstringing during plantarflexion.
Horticultural activity predicts later localized limb status in a contemporary pre‐industrial population
Authors: Stieglitz Jonathan , Trumble Benjamin C. , Kaplan Hillard , Gurven Michael
Published: March 2017

Objectives

Modern humans may have gracile skeletons due to low physical activity levels and mechanical loading. Tests using pre‐historic skeletons are limited by the inability to assess behavior directly, while modern industrialized societies possess few socio‐ecological features typical of human evolutionary history. Among Tsimane forager‐horticulturalists, we test whether greater activity levels and, thus, increased loading earlier in life are associated with greater later‐life bone status and diminished age‐related bone loss.

Materials and Methods

We used quantitative ultrasonography to assess radial and tibial status among adults aged 20+ years (mean ± SD age = 49 ± 15; 52% female). We conducted systematic behavioral observations to assess earlier‐life activity patterns (mean time lag between behavioural observation and ultrasound = 12 years). For a subset of participants, physical activity was again measured later in life, via accelerometry, to determine whether earlier‐life time use is associated with later‐life activity levels. Anthropometric and demographic data were collected during medical exams.

Results

Structural decline with age is reduced for the tibia (female: −0.25 SDs/decade; male: 0.05 SDs/decade) versus radius (female: −0.56 SDs/decade; male: −0.20 SDs/decade), which is expected if greater loading mitigates bone loss. Time allocation to horticulture, but not hunting, positively predicts later‐life radial status (βHorticulture = 0.48, p = 0.01), whereas tibial status is not significantly predicted by subsistence or sedentary leisure participation.

Discussion

Patterns of activity‐ and age‐related change in bone status indicate localized osteogenic responses to loading, and are generally consistent with the logic of bone functional adaptation. Nonmechanical factors related to subsistence lifestyle moderate the association between activity patterns and bone structure.
Accelerating, guiding, and sub‐wavelength trapping of neutral atoms with tailored optical vortices
Authors: Schulze D. , Thakur A. , Moskalenko A.S. , Berakdar J.
Published: March 2017

Single neutral atom mechanics is controllable by focused, high‐intensity optical vortices. The intensity‐dependent, laser‐driven motion of the atom's active electrons subsumes to a net transfer of the orbital angular momentum of the light to the neutral atom. The ponderomotive force on these electrons translates so into an unbounded or a bounded radial drift of the atom depending on its initial kinetic energy, as set by the temperature. Appropriate combination of laser beams results in sub‐wavelength, dynamical radial traps for tweezing atoms controllably, an effect that can be exploited for atom guiding, structuring, and lithographic applications.

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para‐Selective C−H Borylation of (Hetero)Arenes by Cooperative Iridium/Aluminum Catalysis
Authors: Yang Lichen , Semba Kazuhiko , Nakao Yoshiaki
Published: March 2017

para‐Selective C−H borylation of benzamides and pyridines has been achieved by cooperative iridium/aluminum catalysis. A combination of iridium catalysts commonly employed for arene C−H borylation and bulky aluminum‐based Lewis acid catalysts provides an unprecedented strategy for controlling the regioselectivity of C−H borylation to give variously substituted (hetero)arylboronates, which are versatile synthetic intermediates for complex multi‐substituted aromatic compounds.
Insight into Ion Transfer through the Sub‐Nanometer Channels in Zeolitic Imidazolate Frameworks
Authors: Jiang Ze‐Yu , Liu Hai‐Ling , Ahmed Saud Asif , Hanif Sumaira , Ren Shi‐Bin , Xu Jing‐Juan , Chen Hong‐Yuan , Xia Xing‐Hua , Wang Kang
Published: March 2017

A crack‐free sub‐nanometer composite structure for the study of ion transfer was constructed by in situ growth of ZIF‐90 [Zn(ICA)2, ICA=Imidazole‐2‐carboxaldehyde] on the tip of a glass nanopipette. The potential‐driven ion transfer through the sub‐nanometer channels in ZIF‐90 is strongly influenced by the pH of the solution. A rectification ratio over 500 is observed in 1 m KCl solution under alkaline conditions (pH 11.58), which is the highest value reported under such a high salt concentration. Fluorescence experiments show the super‐high rectification ratio under alkaline conditions results from the strong electrostatic interaction between ions and the sub‐nanometer channels of ZIF‐90. In addition to providing a general pathway for further study of mass‐transfer process through sub‐nanometer channels, the approach enable all kinds of metal–organic frameworks (MOFs) to be used as ionic permselectivity materials in nanopore‐based analysis.
Increased Synthetic Control—Gaining Access to Predicted Mg2Si5N8 and β‐Ca2Si5N8
Authors: Bielec Philipp , Schnick Wolfgang
Published: March 2017

Nitridosilicates represent an intriguing class of materials and are typically made up of highly condensed tetrahedral network structures. Alkaline‐earth nitridosilicates emerged as unique host materials for Eu2+ doped luminophores which found broad application in phosphor‐converted (pc)‐LEDs. In contrast to common strategies of preparing nitridosilicates by bottom‐up syntheses, we have now succeeded to post‐synthetically design nitridosilicates by ion exchange in metal halide melts. We describe the syntheses of hitherto unknown but predicted alkaline‐earth nitridosilicates, Mg2Si5N8 and β‐Ca2Si5N8. Both compounds were obtained by ion exchange starting from pre‐synthesized nitridosilicates. In situ investigations of the ion‐exchange process show that the Si–N network topology remains preserved. Therefore the reaction offers a significant increase of synthetic control with respect to classical bottom‐up syntheses.
Boosting the Performance of the Nickel Anode in the Oxygen Evolution Reaction by Simple Electrochemical Activation
Authors: Shinagawa Tatsuya , Ng Marcus Tze‐Kiat , Takanabe Kazuhiro
Published: March 2017

The development of cost‐effective and active water‐splitting electrocatalysts that work at mild pH is an essential step towards the realization of sustainable energy and material circulation in our society. Its success requires a drastic improvement in the kinetics of the anodic half‐reaction of the oxygen evolution reaction (OER), which determines the overall system efficiency to a large extent. A simple electrochemical protocol has been developed to activate Ni electrodes, by which a stable NiOOH phase was formed, which could weakly bind to alkali‐metal cations. The electrochemically activated (ECA) Ni electrode reached a current of 10 mA at <1.40 V vs. the reversible hydrogen electrode (RHE) at practical operation temperatures (>75 °C) and a mild pH of ca. 10 with excellent stability (>24 h), greatly surpassing that of the state‐of‐the‐art NiFeOx electrodes under analogous conditions. Water electrolysis was demonstrated with ECA‐Ni and NiMo, which required an iR‐free overall voltage of only 1.44 V to reach 10 mA cmgeo−2.
Boosting the Energy Density of Carbon‐Based Aqueous Supercapacitors by Optimizing the Surface Charge
Authors: Yu Minghao , Lin Dun , Feng Haobin , Zeng Yinxiang , Tong Yexiang , Lu Xihong
Published: March 2017

The voltage of carbon‐based aqueous supercapacitors is limited by the water splitting reaction occurring in one electrode, generally resulting in the promising but unused potential range of the other electrode. Exploiting this unused potential range provides the possibility for further boosting their energy density. An efficient surface charge control strategy was developed to remarkably enhance the energy density of multiscale porous carbon (MSPC) based aqueous symmetric supercapacitors (SSCs) by controllably tuning the operating potential range of MSPC electrodes. The operating voltage of the SSCs with neutral electrolyte was significantly expanded from 1.4 V to 1.8 V after simple adjustment, enabling the energy density of the optimized SSCs reached twice as much as the original. Such a facile strategy was also demonstrated for the aqueous SSCs with acidic and alkaline electrolytes, and is believed to bring insight in the design of aqueous supercapacitors.
Synthesis and catalytic performance of ferrocene‐based compounds as burning rate catalysts
Authors: Zain‐ul‐Abdin  , Wang Li , Yu Haojie , Saleem Muhammad , Akram Muhammad , Khalid Hamad , Abbasi Nasir M. , Khan Rizwan Ullah
Published: March 2017

To overcome migration problems of ferrocene‐based burning rate catalysts and to enhance burning rate of ammonium perchlorate (AP)‐based propellants, eleven ferrocene‐based compounds (1–11) were synthesized by the condensation reaction of ferrocenecarbonyl chloride with corresponding amines and alcohols. The synthesis of 1–11 was confirmed using 1H NMR, Fourier transform infrared and UV–visible spectroscopy. Their electrochemical properties were analyzed using cyclic voltammetry. The compounds showed redox behavior due to the presence of ferrocene. Their catalytic behavior in the thermal decomposition of AP was investigated using thermogravimetry (TG) and differential TG (DTG). In the presence of 5 wt% 1–11, the thermal decomposition temperature of AP was significantly decreased. TG and DTG analyses showed that 1–11 had a good catalytic effect in the thermal decomposition of AP. Anti‐migration studies showed that migration of 1–11 was slower than that of 2,2‐bis(ethylferrocenyl)propane (catocene) and ferrocene. The effect of the presence of polar elements like oxygen and nitrogen on anti‐migration behavior of small ferrocene‐based compounds was also investigated. Oxygen‐containing compounds showed better anti‐migration behavior than nitrogen‐containing compounds.
Green synthesis of palladium nanoparticles using Hibiscus sabdariffa L. flower extract: Heterogeneous and reusable nanocatalyst in Suzuki coupling reactions
Authors: Hekmati Malak , Bonyasi Fahimeh , Javaheri Hadis , Hemmati Saba
Published: March 2017

An elementary and ecological method has been designed for the biosynthesis of palladium nanoparticles, through the utilization of aqueous extract of red tea (Hibiscus sabdariffa L.) as a reducing and stabilizing agent. The nanoparticles obtained were characterized through UV–visible spectroscopy, transmission election microscopy, X‐ray diffraction, Fourier transform infrared spectroscopy, scanning election microscopy, energy‐dispersive X‐ray analysis and inductively coupled plasma analysis. The nanoparticles with spherical shape and dimensions of approximately 10 nm were used as a heterogeneous catalyst for Suzuki coupling reactions under mild conditions. The high efficiency of the catalytic reaction was affirmed by the good yields of products, easy work‐up, absence of palladium leached from the support and smooth recovery of catalyst.
Synthesis, characterization and biological evaluation of Ru(III) mercaptopyrimidine Schiff base complexes
Authors: Jone Kirubavathy S. , Saranya J. , Sathya N. , Enoch I. V. M. V. , Mosae Selvakumar P. , Chitra S.
Published: March 2017

A new series of mercaptopyrimidine Ru(III) complexes were synthesized and characterized using various spectral techniques like single‐crystal X‐ray diffraction, Fourier transform infrared and NMR spectroscopies, thermogravimetric analysis and energy‐dispersive X‐ray analysis. The complexes were evaluated for their pharmacological activities like in vitro antimicrobial, anticancer, antituberculosis and antioxidant activities. The DNA binding of the complexes was investigated by absorption and emission spectral measurements which indicated that the complexes bind to DNA via intercalation, with molecular docking studies validating the results. DNA cleavage studies of the complexes were carried out.
Sodium cyanide‐promoted copper‐catalysed aerobic oxidative synthesis of esters from aldehydes
Authors: Nowrouzi Najmeh , Abbasi Mohammad , Bagheri Maryam
Published: March 2017

A simple and efficient copper‐catalysed procedure for oxidative esterification of aldehydes with alcohols and phenols mediated by sodium cyanide, using air as a clean oxidant, is described. A variety of aromatic aldehydes and structurally different alcohols and phenols reacted efficiently, and the product esters were obtained in good to excellent yields under normal atmospheric and solvent‐free conditions.
Biocatalysis, DNA–protein interactions, cytotoxicity and molecular docking of Cu(II), Ni(II), Zn(II) and V(IV) Schiff base complexes
Authors: Balakrishnan Chithiraivel , Theetharappan M. , Kowsalya P. , Natarajan Satheesh , Neelakantan M.A. , Mariappan S.S.
Published: March 2017

Four mononuclear metal complexes (Cu(II) (1), Ni(II) (2), Zn(II) (3) and V(IV) (4)) were synthesized using the Schiff base ligand 2,2′‐{cyclohexane‐1,2‐diylbis[nitrilo(1E)eth‐1‐yl‐1‐ylidine]}bis[5‐(prop‐2‐yn‐1‐yloxy)phenol] and structurally characterized by various spectral techniques. The catecholase‐mimicking activities of 1–4 were investigated and the results reveal that all the complexes have ability to oxidize 3,5‐di‐tert‐butylcatechol (3,5‐DTBC) to 3,5‐di‐tert‐butylquinone in aerobic conditions. Electrospray ionization mass spectrometry studies were performed for 1–4 in the presence of 3,5‐DTBC to determine the possible complex–substrate intermediates. X‐band electron paramagnetic resonance spectroscopy results indicate that the metal centres are involved in the catecholase activity. Ligand‐centred radical generation was further confirmed by density functional theory calculation. The phosphatase‐like activity of 1–4 was investigated using 4‐nitrophenylphosphate as a model substrate. All the complexes exhibit excellent phosphatase activity in acetonitrile medium. The interactions of 1–4 with calf thymus DNA (CT‐DNA) and bovine serum albumin (BSA) protein were investigated using absorption and fluorescence titration methods. All the complexes strongly interact with CT‐DNA and BSA protein. The complexes exhibit significant hydrolytic cleavage of supercoiled pUC19 DNA. Complexes 1–4 exhibit significant in vitro cytotoxicity against MCF7 (human breast cancer) and MIA‐PA‐CA‐2 (human pancreatic cancer) cell lines. Moreover, the molecular docking technique was employed to determine the binding affinity with DNA and protein molecules.
TG analysis and kinetic study of organic constituents in wastewater from coal‐gasification process
Authors: Zhang Wei , Wang Chang'an , Li Guangyu , Liu Yinhe , Che Defu
Published: March 2017

In the paper, the thermal reactivity of organic constituents from coal‐gasification wastewater is performed through physicochemical and thermogravimetric (TG) analysis. The effects of reaction atmosphere, oxygen concentration, heating rate, and final temperature on both solids conversion and degradation rate are experimentally studied. The results indicate that organic constituents mainly consist of aliphatic hydrocarbon, phenols, and ammonium, and so on. The thermal degradation of organic constituents in various atmospheres can be divided into four regions: 100–200, 200–300, 300–410, and 410–900 °C. The TG/DTG curves present considerable differences in the last region compared with that in the first three regions. In addition, the degradation rate shows a considerable increase and moves toward higher temperature region with heating rate. Furthermore, the kinetic parameters of organic constituents are analyzed by one multi‐heating rate method. The calculated results show that apparent activation energy of organic constituents varies between 82.8 and 91.3 kJ mol−1 under various reaction atmospheres. This information is potentially useful for the design and retrofitting of the large‐scale equipment to recover industrial wastewater. © 2017 Curtin University of Technology and John Wiley & Sons, Ltd.
Fabrication of highly monodisperse CeO2@poly(methyl silsesquioxane) microspheres and their application in UV‐shielding films
Authors: Yuan Jinfang , Ma Wenshi , Mo Jinpeng
Published: March 2017

Highly monodisperse CeO2@poly(methyl silsesquioxane) (PMSQ) microspheres were successfully prepared by a facile chemical precipitation technique. The structures and properties of CeO2@PMSQ were analyzed by Fourier transform infrared spectroscopy, X‐ray diffraction, and scanning electron microscopy techniques. We confirmed that the PMSQ microspheres were uniformly coated by CeO2 nanoparticles, with about an 8 nm crystallite diameter. Then, CeO2@PMSQ was incorporated into a poly(vinyl alcohol) (PVA) matrix to fabricate PVA/CeO2@PMSQ composite films by the casting of homogeneous solutions. The thermal and optical properties of the composite films were investigated by thermogravimetric analysis and UV–visible spectroscopy. The results show the high UV‐shielding efficiency of the composites: for a film containing 2.5 wt % CeO2@PMSQ microspheres, about 80% UV light at wavelengths between 200 and 360 nm was absorbed, whereas the optical transparency in the visible region still remained very high. The addition of CeO2@PMSQ microspheres improved the thermal stability of the PVA films. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45065.
Surface modification of polyamide TFC membranes via redox‐initiated graft polymerization of acrylic acid
Authors: Hong Anh Ngo Thu , Dinh Do Khai , Thi Tran Dung
Published: March 2017

In this work, the redox‐initiated graft polymerization of acrylic acid (AA) onto the surface of polyamide thin film composite membranes has been carried out to enhance membrane separation and antifouling properties. The membrane surface characteristics were determined through the attenuated total reflection Fourier transform infrared spectra, scanning electron microscopy, atomic force microscopy, and water contact angles. The membrane separation performance was evaluated through membrane flux and rejection of some organic compounds such as reactive red dye (RR261), humic acid, and bovine serum albumin in aqueous feed solutions. The experimental results indicated that the membrane surfaces became more hydrophilic and smoother after grafting of AA. The modified membranes have a better separation performance with a significant enhancement of flux at a great retention. The fouling resistance of the modified membranes is also clearly improved with the higher maintained flux ratio and the lower irreversible fouling factor compared to the unmodified one. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45110.
Conservation implications of establishment success of the Critically Endangered Twee River redfin ‘Pseudobarbus’ erubescens (Skelton, ) in an artificial impoundment in South Africa
Authors: Jordaan Martine S. , van der Walt Johannes A. , Brink Zanné , Erasmus Sonja , Weyl Olaf L. F.
Published: March 2017

This study reports the first known record of breeding of the Critically Endangered Twee River redfin ‘Pseudobarbus’ erubescens in an artificial impoundment. This followed an introduction of 48 individuals into a 10 ha impoundment within the species' native range more than a decade ago.

Sampling the impoundment using three fyke nets set overnight yielded 2838 P. erubescens, which included both juveniles and adults capable of spawning. Fork length measurements of a subsample of 250 individuals ranged from 29 to 125 mm with length cohorts indicating multiple spawning events.

This demonstrates that this species can successfully reproduce in lentic environments and suggests that artificial impoundments could be stocked to provide refugia for P. erubescens and other highly threatened small cyprinids while conservation strategies are developed to mitigate against habitat loss resulting from alien fish invasions, increased human use of water, and from climate change in rivers.
The Brain of the Giraffe (Giraffa Camelopardalis): Surface Configuration, Encephalization Quotient, and Analysis of the Existing Literature
Authors: Graïc Jean‐Marie , Peruffo Antonella , Ballarin Cristina , Cozzi Bruno
Published: March 2017

The anatomy of the giraffe (Giraffa camelopardalis Linnaeus, 1758) has been poorly studied, except for the circulatory system. In particular, only a handful of studies have concerned the brain of this species since the first description in 1839. Accordingly, only a very few articles discussing encephalization mentioned the giraffe or used it in their calculations. In this article, we performed a thorough examination of the literature including old and grey, regarding the central nervous system of the giraffe. Furthermore, we examined the brain of 3 giraffes, and calculated the encephalization quotient (EQ) of the species, based on our own data and the values found in the literature. We also revised the pre‐existing literature and re‐mapped the main sulci based on current comparative interpretation and anatomical nomenclature. Our results were compared to those of other selected significant mammals. The mean brain weight was of 719.9 ± 12.5 g. Our data indicate that the EQ of the giraffe is 0.64 and matches that of the typical ungulate, despite having the largest brain among terrestrial Cetartiodactyla. This emphasizes that the giraffe is a highly specialized mammal, within the limitations of its clad. Anat Rec, 300:1502–1511, 2017. © 2017 Wiley Periodicals, Inc.
Characterization of two novel antimicrobial peptides from the cuticular extracts of the ant Trichomyrmex criniceps (Mayr), (Hymenoptera: Formicidae)
Authors: Bhagavathula Nagachaitanya , Meedidoddi Venkateshwarlu , Bourque Simon , Vimaladevi Reshmy , Kesavakurup Santoshkumar , Selvadurai Dayanandan , Shrivastava Sameer , Krishnappa Chandrashekara
Published: March 2017

Antimicrobial peptides (AMPs) from cuticular extracts of worker ants of Trichomyrmex criniceps (Mayr, Hymenoptera: Formicidae) were isolated and evaluated for their antimicrobial activity. Eight peptides ranging in mass from 804.42 to 1541.04 Da were characterized using a combination of analytical and bioinformatics approach. All the eight peptides were novel with no similarity to any of the AMPs archived in the Antimicrobial Peptide Database. Two of the eight novel peptides, the smallest and the largest by mass were named Crinicepsin‐1 and Crinicepsin‐2 and were chemically synthesized by solid phase peptide synthesis. The two synthetic peptides had antibacterial and weak hemolytic activity.
Establishing nucleosome architecture and stability at promoters: Roles of pioneer transcription factors and the RSC chromatin remodeler
Authors: Kubik Slawomir , Bruzzone Maria Jessica , Shore David
Published: March 2017

Improvements in deep sequencing, together with methods to rapidly deplete essential transcription factors (TFs) and chromatin remodelers, have recently led to a more detailed picture of promoter nucleosome architecture in yeast and its relationship to transcriptional regulation. These studies revealed that ∼40% of all budding yeast protein‐coding genes possess a unique promoter structure, where we propose that an unusually unstable nucleosome forms immediately upstream of the transcription start site (TSS). This “fragile” nucleosome (FN) promoter architecture relies on the combined action of the essential RSC (Remodels Structure of Chromatin) nucleosome remodeler and pioneer transcription factors (PTFs). FNs are associated with genes whose expression is high, coupled to cell growth, and characterized by low cell‐to‐cell variability (noise), suggesting that they may promote these features. Recent studies in metazoans suggest that the presence of dynamic nucleosomes upstream of the TSS at highly expressed genes may be conserved throughout evolution.
Impact of age and mismatch repair status on survival in colorectal cancer
Authors: Li Pan , Xiao Zhi‐Tao , Braciak Todd A. , Ou Qing‐Jian , Chen Gong , Oduncu Fuat S.
Published: March 2017

Previous studies have suggested that deficiencies in mismatch repair genes (dMMR) often occur in patients with colorectal cancer (CRC) and contribute to disease etiology. Here, we looked for a correlation of MMR status to disease outcomes from a large number of Chinese CRC patients stratified by the age of onset of disease. A total of 2233 CRC patients were analyzed and tissue biopsies of surgically removed tumors scored for MMR gene status. The patient distribution after classification consisted of 188 younger aged patients (20–39 years of age), 1024 middle aged patients (40–59 years of age), and 1020 older aged patients (60–85 years of age). In this analysis, the expression of four MMR genes was assessed by immunohistochemistry (IHC). We found that the young group of CRC patients with dMMR had higher overall survival (OS) than the young group of patients with proficient MMR (pMMR) (77% vs. 56%, P = 0.03). Middle‐aged patients with dMMR also had higher OS than middle‐aged group patients with pMMR (78% vs. 68%, P = 0.012). However, we found no statistical difference in OS between dMMR and pMMR status in the older group of patients (75% vs. 71%, P = 0.224). Finally, the middle‐ and older‐aged group set of patients had higher OS than the young group of patients (69% vs. 71% vs. 59%, P = 0.008). These data demonstrated that the age of disease onset can be an important factor to help evaluate the prognosis of CRC when combined with the analysis of MMR status within tumor biopsied tissue.
Small Molecules Targeting Human N‐Acetylmannosamine Kinase
Authors: Hinderlich Stephan , Neuenschwander Martin , Wratil Paul R. , Oder Andreas , Lisurek Michael , Nguyen Long D. , von Kries Jens P. , Hackenberger Christian P. R.
Published: March 2017

N‐Acetylmannosamine kinase (MNK) plays a key role in the biosynthesis of sialic acids and glycosylation of proteins. Sialylated glycoconjugates affect a large number of biological processes, including immune modulation and cancer transformation. In search of effective inhibitors of MNK we applied high‐throughput screening of drug‐like small molecules. By applying different orthogonal assays for their validation we identified four potential MNK‐specific inhibitors with IC50 values in the low‐micromolar range. Molecular modelling of the inhibitors into the active site of MNK supports their binding to the sugar or the ATP‐binding pocket of the enzyme or both. These compounds are promising for downregulation of the sialic acid content of glycoconjugates and for studying the functional contribution of sialic acids to disease development.
Iron Nanoparticles Embedded in Graphitic Carbon Matrix as Heterogeneous Catalysts for the Oxidative C−N Coupling of Aromatic N−H Compounds and Amides
Authors: He Jinbao , Dhakshinamoorthy Amarajothi , Primo Ana , Garcia Hermenegildo
Published: March 2017

Fe or Co nanoparticles (NPs) and two nanoparticulate Fe‐Co alloys having different Fe/Co atomic ratio with average particle size ranging from 10.9 to 26.5 nm embedded in turbostratic graphitic carbon matrix have been prepared by pyrolysis at 900 °C under inert atmosphere of chitosan powders containing Fe2+ and Co2+ ions in various proportions. The resulting Fe/Co NP@C samples have been evaluated as heterogeneous catalysts for the oxidative C−N coupling of amides and aromatic N−H compounds. It was observed that sequential addition of two aliquots of tert‐butyl hydroperoxide (TBHP) in an excess of N,N‐dimethylacetamide (DMA) as solvent affords the corresponding coupling product in high yields, and the most efficient catalyst was Fe NP@C. Fe NP@C is reusable and exhibits a wide scope. The catalytic activity of Fe is supported by using highly pure Fe salt and by the observation that purposely addition of Cu2+ impurities even plays a detrimental effect on the catalytic activity. Mechanistic studies by quenching with 2,2,6,6‐tetramethylpiperidyl‐1‐oxyl (TEMPO) have shown that the amide radical is the key reaction intermediate, and the role of Fe NP@C is to generate the first radicals by TBHP decomposition.
Application of Thiol–yne/Thiol–ene Reactions for Peptide and Protein Macrocyclizations
Authors: Wang Yuanxiang , Bruno Benjamin J. , Cornillie Sean , Nogieira Jason M. , Chen Diao , Cheatham Thomas E. , Lim Carol S. , Chou Danny Hung‐Chieh
Published: March 2017

The application of thiol–yne/thiol–ene reactions to synthesize mono‐ and bicyclic‐stapled peptides and proteins is reported. First, a thiol–ene‐based peptide‐stapling method in aqueous conditions was developed. This method enabled the efficient stapling of recombinantly expressed coil‐coiled proteins. The resulting stapled protein demonstrated higher stability in its secondary structure than the unstapled version. Furthermore, a thiol–yne coupling was performed by using an α,ω‐diyne to react with two cysteine residues to synthesize a stapled peptide with two vinyl sulfide groups. The stapled peptide could further react with another biscysteine peptide to yield a bicyclic stapled peptide with enhanced properties. For example, the cell permeability of a stapled peptide was further increased by appending an oligoarginine cell‐penetrating peptide. The robustness and versatility of thiol–yne/thiol–ene reactions that can be applied to both synthetic and expressed peptides and proteins were demonstrated.
Multi‐Electron Oxidation of Anthracene Derivatives by Nonheme Manganese(IV)‐Oxo Complexes
Authors: Sharma Namita , Jung Jieun , Lee Yong‐Min , Seo Mi Sook , Nam Wonwoo , Fukuzumi Shunichi
Published: March 2017

Six‐electron oxidation of anthracene to anthraquinone by a nonheme MnIV‐oxo complex, [(Bn‐TPEN)MnIV(O)]2+, proceeds through a rate‐determining electron transfer from anthracene to [(Bn‐TPEN)MnIV(O)]2+, followed by subsequent fast oxidation reactions to give anthraquinone. The reduced MnII complex ([(Bn‐TPEN)MnII]2+) is oxidized by [(Bn‐TPEN)MnIV(O)]2+ rapidly to produce the μ‐oxo dimer ([(Bn‐TPEN)MnIII‐O‐MnIII(Bn‐TPEN)]4+). The oxygen atoms of the anthraquinone product were found to derive from the manganese‐oxo species by the 18O‐labelling experiments. In the presence of Sc3+ ion, formation of an anthracene radical cation was directly detected in the electron transfer from anthracene to a Sc3+ ion‐bound MnIV(O) complex, [(Bn‐TPEN)MnIV(O)‐(Sc(OTf)3)2]2+, followed by subsequent further oxidation to yield anthraquinone. When anthracene was replaced by 9,10‐dimethylanthracene, electron transfer from 9,10‐dimethylanthracene to [(Bn‐TPEN)MnIV(O)‐(Sc(OTf)3)2]2+ occurred rapidly to produce stable 9,10‐dimethylanthracene radical cation. The driving force dependence of the rate constants of electron transfer from the anthracene derivatives to [(Bn‐TPEN)MnIV(O)]2+ and [(Bn‐TPEN)MnIV(O)‐(Sc(OTf)3)2]2+ was well‐evaluated in light of the Marcus theory of electron transfer.
A Synthetic Route to β‐Hydroxytyrosine‐Derived Tetramic Acids: Total Synthesis of the Fungal Metabolite F‐14329
Authors: Bruckner Sebastian , Haase Robert G. , Schobert Rainer
Published: March 2017

3‐Acyltetramic acids derived from β‐hydroxytyrosine are synthetically challenging. The first route to this structural motif, based upon a condensation between a Meldrum's acid conjugate bearing the acyl side chain, and a β‐hydroxytyrosinate, N‐protected by an ortho‐nitrobenzyl group is presented. This group enables the Dieckmann cyclization of the resulting N‐(β‐ketoacyl)amino ester, after which it can be removed photolytically without compromising the delicate 3′‐hydroxy group. This strategy was applied to the first total synthesis of the fungal metabolite F‐14329 (1).
Tunable GLUT–Hexose Binding and Transport via Modulation of Hexose C‐3 Hydrogen‐Bonding Capabilities
Authors: Kumar Kondapi Venkata Pavan , Soueidan Olivier‐Mohamad , Cheeseman Christopher I. , West Frederick G.
Published: March 2017

The importance of the hydrogen bonding interactions in the GLUT–hexose binding process (GLUT=hexose transporter) has been demonstrated by studying the binding of structurally modified d‐fructose analogues to GLUTs, and in one case its transport into cells. The presence of a hydrogen bond donor at the C‐3 position of 2,5‐anhydro‐d‐mannitol derivatives is essential for effective binding to GLUT5 and transport into tumor cells. Surprisingly, installation of a group that can function only as a hydrogen bond acceptor at C‐3 resulted in selective recognition by GLUT1 rather than GLUT5. A fluorescently labelled analogue clearly showed GLUT‐mediated transport and low efflux properties of the probe. This study reveals that a single positional modification of a 2,5‐anhydro‐d‐mannitol derivative is sufficient to switch its binding preference from GLUT5 to GLUT1, and uncovers general scaffolds that are suitable for the potential selective delivery of molecular payloads into tumor cells via GLUT transport machinery.
Reaktionstechnik und Mischvorgänge: Zwei untrennbare Fachgebiete
Authors: Klemm Elias , Kraume Matthias , Ritter Joachim , Sauer Jörg
Published: March 2017

No abstract.