bluuebunny/crossref_metadata_2025 huggingface dataset:
Copper‐Catalyzed Glaser‐Hey‐Type Cross Coupling of 9‐Ethynyl‐α‐Noscapine Leading to Unsymmetrical 1,3‐Diynyl Noscapinoids
Authors: Nagireddy Praveen K. R. , Sridhar Balasubramanian , Kantevari Srinivas
Published: July 2019

Cu(I)‐catalyzed Glaser‐Hey‐type cross coupling of 9‐ethynylnoscapine with terminal alkynes has been described that enables synthesis of unsymmetrical noscapine 1,3‐diynes in very good yields in the presence of base and amines as ligands. The symmetrical dimer of 9‐ethynylnoscapine was also isolated as by‐product. Outcome of these couplings critically depends on the choice of ligands and base as well as employed reaction conditions. The synthesized 1,3‐diyne analogues were evaluated for their antiproliferative activity.
Recent Advances in the Functionalization of Hydrocarbons: Synthesis of Amides and its Derivatives
Authors: Reddy Thatikonda Narendar , de Lima Dênis Pires
Published: July 2019

The functionalization of hydrocarbons represents an attractive approach for the synthesis of amides. The amide bond is one of the most fascinating functional groups in nature, owing to its high bond polarity, stability, and conformational diversity. Amides play an essential role in the composition of many natural products, agrochemicals, peptides, polymers, proteins, biologically active systems, and functional materials. The present review focuses on recent breakthroughs and current challenges for the functionalization of hydrocarbons to synthesize amides. This review provides comprehensive coverage on recent reports of various efficient metal‐catalyzed and metal‐free methods for the synthesis of amides from hydrocarbons (such as methylarenes, alkenes, and alkynes). We also show the reaction mechanisms of representative reactions in a detailed way with numerous examples and applications of these methods in the synthesis of bioactive compounds.
Syntheses and Biological Properties of Pyrido[3,4‐b]homotropane (PHT) and its Analogues with Bridged Aza‐[n.2.1] Skeletons
Authors: Sun Bingxia , Wang Zhongwen
Published: July 2019

The nicotinic acetylcholine receptor (nAChR) is one of the targets for developing drugs for the treatment of central nervous system (CNS) disorders and for control of agricultural pests. Pyrido[3,4‐b] homotropane (PHT) was originally designed and synthesized by Kanne and co‐workers and showed strong affinity binding to nAChR. PHT has a novel aza‐[4.2.1]nonane skeleton. Owing to its excellent biological activities and novel chemical structure, synthetic and medicinal chemists have been attracted by this molecule. Some PHT analogues with bridged aza‐[n.2.1] skeletons were also designed and synthesized via different strategies. Herein, we summarize the syntheses of PHT and its analogues. Their biological activity study is also briefly discussed.
Diet and adult age‐at‐death among mobile foragers: A synthesis of bioarcheological methods
Authors: Pfeiffer Susan , Cameron Michelle E. , Sealy Judith , Beresheim Amy C.
Published: July 2019

Objectives

The research explores whether the combined study of cortical bone histology, bone morphology, and dietary stable isotopes can expand insights into past human health and adaptations, particularly dietary sufficiency and life span.

Materials and methods

Midthoracic rib cortices from 54 South African Late Holocene adult skeletons (28 M, 24 F, two sex undetermined) are assessed by transmitted‐light microscopy for cross‐sectional area measurements, osteon area (On.Ar), osteon population density, and presence/absence of secondary osteon variants. Values for δ13Cbone collagen, δ15Nbone collagen, 14C dates, Southwestern and Southern Cape geographic regions, body size measures, estimated ages‐at‐death from both morphological and histological methods are integrated into analyses, which include Spearman correlations, χ2 tests and Kruskal–Wallis ANOVAs.

Results

There is reduced On.Ar variability with higher δ15N (r = −.41, p = .005); rib %cortical area and δ15N are negatively correlated in the Southern Cape group (r = −.60, p = .03). Osteon variants are more common in older adults; histological ages at death are significantly older than those determined from gross morphology.

Discussion

We found bone tissue relationships with measures of diet composition, but indicators of dietary adequacy remain elusive. Relationships of tissue quality and isotopes suggest that some Southern Cape adults lived long lives. Osteon variants are associated with age‐at‐death; some association with diet remains possible. Gross morphological methods appear to underestimate adult ages‐at‐death, at least among small‐bodied adults.
Root caries on a Paranthropus robustus third molar from Drimolen
Authors: Towle Ian , Riga Alessandro , Irish Joel D. , Dori Irene , Menter Colin , Moggi‐Cecchi Jacopo
Published: July 2019

Objectives

Dental caries is often perceived as a modern human disease. However, their presence is documented in many early human groups, various nonhuman primates and, increasingly, our hominin ancestors and relatives. In this study, we describe an antemortem lesion on the root of a Paranthropus robustus third molar from Drimolen, South Africa, which likely represents another example of caries in fossil hominins.

Materials and Methods

The molar, DNH 40, is dated to 2.0–1.5 Ma and displays a lesion on the mesial root surface, extending from the cementoenamel junction 3 mm down toward the apex. The position and severity of the lesion was macroscopically recorded and micro‐CT scanned to determine the extent of dentine involvement.

Results

A differential diagnosis indicates root caries, as the lesion is indistinguishable from clinical examples. Although necrotic in appearance, external tertiary dentine is evident on a micro CT scan. Gingival recession and/or continuous eruption of the tooth as a result of extensive occlusal wear would have occurred to facilitate caries formation. Therefore, the lesion is likely linked to relative old age of this individual.

Discussion

This new example increases the total number of carious lesions described in P. robustus teeth to 10, on occlusal, interproximal, and now, root surfaces. Beyond the consumption of caries‐causing food, caries formation would have also required the presence of requisite intraoral cariogenic bacteria in this individual and the species. Of interest, the presence of tertiary dentine on the outward surface suggests the DNH 40 lesion may have been arrested, that is, no longer active, perhaps relating to a change in diet or oral microbiome just prior to the individual's death.
Catalytic Asymmetric Synthesis of Cyclohexanes by Hydrogen Borrowing Annulations
Authors: Armstrong Roly J. , Akhtar Wasim M. , Young Tom A. , Duarte Fernanda , Donohoe Timothy J.
Published: July 2019

Hydrogen borrowing catalysis serves as a powerful alternative to enolate alkylation, enabling the direct coupling of ketones with unactivated alcohols. However, to date, methods that enable control over the absolute stereochemical outcome of such a process have remained elusive. Here we report a catalytic asymmetric method for the synthesis of enantioenriched cyclohexanes from 1,5‐diols via hydrogen borrowing catalysis. This reaction is mediated by the addition of a chiral iridium(I) complex, which is able to impart high levels of enantioselectivity upon the process. A series of enantioenriched cyclohexanes have been prepared and the mode of enantioinduction has been probed by a combination of experimental and DFT studies.
An All‐Alkynyl Protected 74‐Nuclei Silver(I)–Copper(I)‐Oxo Nanocluster: Oxo‐Induced Hierarchical Bimetal Aggregation and Anisotropic Surface Ligand Orientation
Authors: Yang Yang , Jia Tao , Han Ying‐Zi , Nan Zi‐Ang , Yuan Shang‐Fu , Yang Feng‐Lei , Sun Di
Published: July 2019

The hardness of oxo ions (O2−) means that coinage‐metal (Cu, Ag, Au) clusters supported by oxo ions (O2−) are rare. Herein, a novel μ4‐oxo supported all‐alkynyl‐protected silver(I)–copper(I) nanocluster [Ag74−xCuxO12(PhC≡C)50] (NC‐1, avg. x=37.9) is characterized. NC‐1 is the highest nuclearity silver–copper heterometallic cluster and contains an unprecedented twelve interstitial μ4‐oxo ions. The oxo ions originate from the reduction of nitrate ions by NaBH4. The oxo ions induce the hierarchical aggregation of CuI and AgI ions in the cluster, forming the unique regioselective distribution of two different metal ions. The anisotropic ligand coverage on the surface is caused by the jigsaw‐puzzle‐like cluster packing incorporating rare intermolecular C−H⋅⋅⋅metal agostic interactions and solvent molecules. This work not only reveals a new category of high‐nuclearity coinage‐metal clusters but shows the special clustering effect of oxo ions in the assembly of coinage‐metal clusters.
Green synthesis of silver nanoparticles using aqueous extract of Stachys lavandulifolia flower, and their cytotoxicity, antioxidant, antibacterial and cutaneous wound‐healing properties
Authors: Zangeneh Mohammad Mahdi , Joshani Zeinab , Zangeneh Akram , Miri Elnaz
Published: July 2019

In a biological process where the herbal tea (Stachys lavandulifolia) aqueous extract was applied as a capping and reducing agent, nanoparticles (NPs) of silver (Ag) were synthesized. These AgNPs were characterized using Fourier transform‐infrared spectroscopy, field emission‐scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, transmission electron microscopy and ultraviolet–visible spectroscopy. The synthesized AgNPs had great cell viability dose‐dependently [investigating the effect of the plant on human umbilical vein endothelial cell line] and indicated this method was non‐toxic. In this study, the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) free radical scavenging test was carried out to examine antioxidant properties, which revealed similar antioxidant properties for AgNPs and butylated hydroxytoluene. Agar diffusion tests were applied to determine the antibacterial characteristics. The macro‐broth tube test was run to determine minimum inhibitory concentration. All data of antibacterial and cutaneous wound‐healing examinations were analyzed by SPSS 21 software (Duncan post hoc test). AgNPs showed higher antibacterial property than all standard antibiotics (p ≤ 0.01). Also, AgNPs prevented the growth of all bacteria at 2–8 mg/ml concentrations and destroyed them at 2–16 mg/ml concentrations (p ≤ 0.01). For the in vivo experiment, after creating the cutaneous wound, the rats were randomly divided into six groups: untreated control; treatment with Eucerin basal ointment; treatment with 3% tetracycline ointment; treatment with 0.2% AgNO3 ointment; treatment with 0.2% S. lavandulifolia ointment; and treatment with 0.2% AgNPs ointment. These groups were treated for 10 days. For histopathological and biochemical analysis of the healing trend, a 3 × 3‐cm section was prepared from all dermal thicknesses at day 10. Use of AgNPs ointment in the treatment groups substantially reduced (p ≤ 0.01) the wound area, total cells, neutrophil, macrophage and lymphocyte, and remarkably raised (p ≤ 0.01) the wound contracture, hydroxyl proline, hexosamine, hexuronic acid, fibrocyte and fibrocytes/fibroblast rate compared with other groups. Seemingly, AgNPs can be used as a medical supplement owing to their non‐cytotoxic, antioxidant, antibacterial and cutaneous wound‐healing properties.
Metalloporphyrins‐Al3+porous coordination polymers: Preparations, Characterizations and Catalytic Properties
Authors: Song Dengmeng , Bai Xiaolong , Yang Yong , Zhao Xin , Wang Ning , Li Jun
Published: July 2019

In this work, metalloporphyrins‐based MOGs were synthesized as precursor to prepare porous coordination polymers (PCPs). Firstly, the carboxyl metalloporphyrins MCPp (M = Zn (II), Co (II), Cu (II), Mn (III)OAc; CPp = 5,10,15,20‐tetra(4‐(3‐carboxy)phenoxy)phenylporphyrin) were synthesized as gelator. Then, the metalloporphyrin‐based MOGs were prepared with MCPp and Al(NO3)3·9H2O by sol–gel method. Moreover, the residual reactants and solvent molecules in MOGs were removed by Soxhlet extraction and supercritical CO2extraction to get the finial porous coordination polymers. This methodology effectually avoids the collapse of frame construction. Compared with the reference material prepared by the oven‐dry method, these PCPs exhibit much higher BET surface ranging from 398 to 439 m2 g−1. The PCPs were carefully characterized by FT‐IR, UV–vis, SEM, TEM and PXRD, and exhibit excellent catalytic activities and stabilities for the oxidation of ethylbenzene.
Synthesis of Pyrazolo‐[4́,3́:5,6]pyrido[2,3‐d]pyrimidine‐diones Catalyzed by a Nano‐sized Surface‐Grafted Neodymium Complex of the Tungstosilicate via Multicomponent Reaction
Authors: Daraie Mansoureh , Heravi Majid M. , Mirzaei Masoud , Lotfian Nahid
Published: July 2019

An inorganic–organic hybrid based on lanthanide clusters and Keggin type polyoxometalates (POMs) (Na[Nd (pydc‐OH)(H2O)4]3}[SiW12O40]) was used the first time as trinuclear catalyst for one pot synthesis of pyrazolo[4́́,3́:5,6]pyrido[2,3‐d]pyrimidine‐diones, via two different four and five‐component reactions involving hydrazine hydrate, ethyl acetoacetate, aryl aldehydes, and 6‐amino‐1,3‐dimethyl uracil or barbituric acid with ammonium acetate as alternative materials in green condition. To evaluate potential application of the as‐made hybrid in adsorption and separation processes, nitrogen adsorption was performed at 77 K through simulation study. The hybrid catalyst was further characterized via powder X‐ray diffraction (PXRD) at room temperature which indicated the good phase purity of the catalyst. The results show that the catalytic activity of the hybrid catalyst has increased relative to each parent component due to the special interaction between Keggin anions and pydc‐OH ligands.
Land‐based and climatic stressors of mangrove cover change in the Auckland Region, New Zealand
Authors: Suyadi  , Gao Jay , Lundquist Carolyn J. , Schwendenmann Luitgard
Published: July 2019

Changes in mangrove forest cover (increases and decreases) have been observed globally as a result of the influence of environmental changes and human impacts. Although mangrove forest increases are globally uncommon, in New Zealand mangroves are increasing in distribution at the expense of other intertidal estuarine habitats.

This study quantified the change in mangrove area over a period of 74 years (1940–2014), and investigated the influence of land‐based (e.g. land use conversion in the catchments), climatic, and oceanic factors on the change in temperate mangrove forest cover in the Auckland Region of New Zealand over that period.

An improved mapping approach using aerial photographs and Landsat images was applied to quantify changes in tall and dwarf mangrove cover, and to identify the mechanism of change (expansion, gap filling, and loss), across 38 estuaries in the Auckland Region, New Zealand.

Mangrove area increased from 2313 ha in 1940 to 10 483 ha in 2014 (on average 3.2% yr−1), with higher rates in small estuaries (<1000 ha) than in large estuaries (>1000 ha). The area of the intertidal mudflat habitat, i.e. potential area for mangrove colonization, has doubled from 14 193 ha in 1974 to 28 764 ha in 2014. The increase in total mangrove area was explained primarily by gap filling followed by expansion. The proportion of expansion‐related increase was predominantly seaward (82%) but mangroves also expanded upstream (16%).

Boosted regression tree analysis revealed that catchment forest cover, sea level, and mean annual air temperature explained around 85% of the variation in mangrove area. Periods of catchment forest clearing coincided with gains in mangrove forest area. Dwarf mangroves were more sensitive to changes in sea level, in particular over the past 25 years, when the annual sea‐level rise exceeded the sediment accumulation rates.

Catchment land use, especially the clearing of forests, associated with increased sediment supply into estuaries is the strongest driver of mangrove forest gain. Thus, land‐use management is a necessary aspect of the management of New Zealand estuaries to conserve the diversity of estuarine habitats (including mangroves) and the ecosystem services that each habitat provides.
Counter‐Anion‐Regulated Mixed‐Valency of Cobalt(II/III) Centers in a Metallosupramolecular Framework
Authors: Hashimoto Akari , Yoshinari Nobuto , Nakano Motohiro , Konno Takumi
Published: July 2019

A diamagnetic AuI4CoIII2 hexanuclear complex, [Au4Co2(dppe)2(l‐nmc)4]2+ ([1L‐nmc]2+; dppe=1,2‐bis(diphenylphosphino)ethane, l‐H2nmc=N‐methyl‐l‐cysteine), was newly synthesized by the reaction of [Co(l‐nmc)2]− with [Au2Cl2(dppe)] and crystallized with different inorganic anions (X=ClO4−, NO3−, Cl−, SO42−) to produce ionic solids ([1L‐nmc]Xn). Single‐crystal X‐ray analysis revealed that all the solids crystallize in the chiral space group F432 with a face‐centered‐cubic lattice structure consisting of supramolecular octahedra of complex cations. The paramagnetic nature of all the solids was evidenced by magnetic susceptibility measurements, showing the variation of the oxidation states of two cobalt centers in [1L‐nmc]n+ from CoII1.00CoIII1.00 for X=ClO4− or NO3− to CoII0.67CoIII1.33 for X=Cl−, via CoII0.83CoIII1.17 for X=SO42−. The difference in the CoII/III mixed‐valences was explained by the difference in sizes and charges of counter anions accommodated in lattice interstices with a fixed volume.
R CrB: Long‐period variations of radial velocity and velocity of outflow
Authors: Rosenbush A.
Published: July 2019

The recently discovered variation in the mean radial velocity (RV) of R CrB on a time scale of about 10,000 days may be associated with a long‐term pulsation of a star with the amplitude of about 2.5 km s−1, which results in the known mass loss of the star at the rate of 10−6 times the mass of the Sun. It is also possible the connection with the 46‐year cycle in the sequence of the great R CrB declines. The absence of an obvious connection between the onset of R CrB decline and a certain phase of the 40‐day pulsation is suggested to relate to a long time delay between the processes in the noncoherently pulsating photosphere and in the zone of dust condensation. The search for the long‐term variability of the RV of R CrB from the data of the recently published large homogeneous database made it possible to identify two types of unique behavior of the RV in the JD 2451500–2454400 interval immediately before the unique Great decline in 2007. At first, the RV showed a superposition of known 40‐day pulsations of six pulsations with a period of 238 days, an average velocity of 25 km s−1 and amplitude of 3 km s−1. Near JD 2454600, this pulsation was abruptly replaced by the 792‐day cycle. The cycle has a radically different half, with an average velocity about of 24.5 km s−1. The first half can be termed abnormal because of the unique central 40‐day pulsation with a very high amplitude of about 14 km s−1. The second half of cycle is a superposition of the half‐wave normal‐like prolonged pulsation and pulsations with a period of about 42 days and an amplitude of about 3 km s−1. At the beginning of the third cycle, the IV Great RCB‐type decline started.
Multi‐spectroscopic and molecular dynamics simulations investigation of the binding mechanism of polybrominated diphenyl ethers to hen egg white lysozyme
Authors: Zuo Yanqiu , Rui Yuefan , Xu Jie , Yang Lulu , Yi Zhongsheng
Published: July 2019

Three PBDEs (BDE25, BDE47, and BDE154) were selected to investigate the interactions between PBDEs and hen egg white lysozyme (HEWL) by molecular modeling, fluorescence spectroscopy, and FT‐IR spectra. The docking results showed that hydrogen bonds were formed between BDE25 and residue TRP63 and between BDE47 and TRP63 with bond lengths of 2.178 Å and 2.146 Å, respectively. The molecular dynamics simulations indicated that van der Waals forces played a predominant role in the binding of three PBDEs to HEWL. The observed fluorescence quenching can be attributed to the formation of complexes between HEWL and PBDEs, and the quenching mechanism is a static quenching. According to Förster's non‐radiative energy transfer theory, the binding distances r were < 7 nm, indicating a high probability of energy transfer from HEWL to the three PBDEs. The synchronous fluorescence showed that the emission maximum wavelength of tryptophan (TRP) residues emerged a red‐shift. FT‐IR spectra indicated that BDE25, BDE47 and BDE154 induced the α‐helix percentage of HEWL decreased from 32.70% ± 1.64% to 28.27% ± 1.41%, 27.50% ± 1.38% and 29.78% ± 1.49%, respectively, whereas the percentage of random coil increased from 26.67% ± 1.33% to 27.60% ± 1.38%, 29.18% ± 1.46% and 30.59% ± 1.53%, respectively.
Simultaneous determination of eight bioactive components of Cirsium setosum flavonoids in rat plasma using triple quadrupole LC/MS and its application to a pharmacokinetic study
Authors: Wang He Chen , Bao Yong Rui , Wang Shuai , Li Tian Jiao , Meng Xian Sheng
Published: July 2019

Cirsium setosum (Willd.) MB. has been reported to exert significant anti‐hemorrhagic, anti‐inflammation, antimicrobial, sedative and detoxicating efficacy. It has been widely used to treat gastrointestinal bleeding, uterine bleeding, infectious hepatitis and cardiovascular disease in China. Recent studies have shown that flavonoids are the main active components in C. setosum. Nevertheless, to the best of our knowledge, there is no report concerning the simultaneous determinations and pharmacokinetics of constituents in C. setosum flavonoids in rat plasma. In this study, a rapid, sensitive and selective triple quadrupole liquid chromatography–mass spectrometry method was developed to determine eight analytes from the flavonoids of C. setosum in rat plasma. In addition, the pharmacokinetic study of the eight analytes in rats after oral administration of C. setosum flavonoids was successfully completed through this method. According to the pharmacokinetic parameters of the eight analytes, rutin, naringin, quercetin, acacetin, wogonin were the long‐acting components of the C. setosum flavonoids, with long elimination time and high bioavailability. Of note, the method developed in this study fills a blank in pharmacokinetic studies of C. setosum flavonoids. Our findings provide valuable views on the understanding of the absorption mechanism of C. setosum flavonoids and their clinical efficacy.
Cuceolatins A–D: New Bioactive Diterpenoids from the Leaves of Cunninghamia lanceolata
Authors: Yu Jin‐Hai , Yu Zhi‐Pu , Wu Dong‐Xiang , Yan Xue , Wang Yin‐Yin , Zhang Hua
Published: July 2019

Four new diterpenoids named cuceolatins A–D, including three labdane‐type (1–3) and one abietane‐type (4) as well as three known labdane analogs (5–7), were reported from the leaves of Cunninghamia lanceolata. Structural assignments for these compounds were conducted by analyses of spectroscopic data, and their absolute configurations were determined by time‐dependent density functional theory (TD‐DFT) based electronic circular dichroism (ECD) calculations. Among them, the abietane‐type diterpenoid (11‐hydroxy‐12‐methoxyabieta‐8,11,13‐trien‐3‐one (4)) showed significant cytotoxicity against human MDA‐MB‐231, MCF‐7, and HeLa tumor cell lines with IC50 measurements of 4.3, 2.8 and 4.5 μm, respectively, while the labdane‐type diterpenoids with a 4α‐carboxy group (1–3 and 5) exhibited moderate antibacterial activity towards Bacillus subtilis and Staphylococcus aureus with IC50 values all below 25 μm.
Noble Metal Supported on Activated Carbon for “Hydrogen Free” HDO Reactions: Exploring Economically Advantageous Routes for Biomass Valorisation
Authors: Jin Wei , Santos José Luis , Pastor‐Perez Laura , Gu Sai , Centeno Miguel Angel , Reina Tomas Ramirez
Published: July 2019

An innovative route for bio‐compounds upgrading via “hydrogen‐free” hydrodeoxygenation (HDO) is proposed and evaluated using guaiacol as a model compound in a high‐pressure batch reactor. Experimental results showed that noble metal supported on activated carbon catalysts are able to conduct tandem multiple steps including water splitting and subsequent HDO. The activity of Ru/C catalyst is superior to other studied catalysts (i. e. Au/C, Pd/C and Rh/C) in our water‐only HDO reaction system. The greater dispersion and smaller metal particle size confirmed by the TEM micrographs accounts for the better performance of Ru/C. This material also presents excellent levels of stability as demonstrated in multiple recyclability runs. Overall, the proposed novel approach confirmed the viability of oxygenated bio‐compounds upgrading in a water‐only reaction system suppressing the need of external H2 supply and can be rendered as a fundamental finding for the economical biomass valorisation to produce added value bio‐fuels.
High‐Spin and Low‐Spin Perferryl Intermediates in Fe(PDP)‐Catalyzed Epoxidations
Authors: Zima Alexandra M. , Lyakin Oleg Y. , Bryliakov Konstantin P. , Talsi Evgenii P.
Published: July 2019

Two bioinspired hydroxo‐bridged diferric complexes 6 and 7 with N4‐donor ligands of the PDP type (PDP=N,N′‐bis(pyridin‐2‐ylmethyl)‐2,2′‐bipyrrolidine), differing by substituents at the pyridine rings (4‐NMe2 in 7 vs. 3,5‐Me2‐4‐OMe in 6), efficiently catalyze the enantioselective alkene epoxidation with H2O2 and peracetic acid in the presence of a carboxylic acid additive (up to 99 catalyst turnover numbers, TON, toward epoxide, up to 94 % ee). Catalyst systems based on complex 7 display the high‐spin perferryl intermediate 7 aAA (S=3/2, g1, g2=3.69, g3=1.96), whereas catalyst systems based on complex 6 exhibit the low‐spin perferryl intermediate 6 aAA (S=1/2, g1=2.07, g2=2.01, g3=1.96). The S=3/2 and the S=1/2 intermediates directly react with cyclohexene and cyclohexane at low temperatures (−40 °C and −85 °C, respectively). The catalyst systems, exhibiting less reactive intermediate 7 aAA, demonstrate higher enantioselectivity (% ee) in the epoxidation of chalcone. The origin of the unprecedented high‐spin state of the perferryl intermediate is discussed.
Bioelectrocatalysis on Anodized Epitaxial Graphene and Conventional Graphitic Interfaces
Authors: Vagin Mikhail Yu. , Sekretaryova Alina N. , Håkansson Anna , Iakimov Tihomir , Ivanov Ivan G. , Syväjärvi Mikael , Yakimova Rositsa , Lundström Ingemar , Eriksson Mats
Published: July 2019

Graphitic materials exhibit significant anisotropy due to the difference in conductivity in a single layer and between adjacent layers. This anisotropy is manifested on epitaxial graphene (EG), which can be manipulated on the nanoscale in order to provide tailor‐made properties. Insertion of defects into the EG lattice was utilized here for controllable surface modification with a model biocatalyst and the properties were quantified by both electrochemical and optical methods. A comparative evaluation of the electrode reaction kinetics on the enzyme‐modified 2D material vs conventional carbon electrode materials revealed a significant enhancement of mediated bioelectrocatalysis at the nanoscale.
Recent Advances in Zinc‐Containing Colloidal Semiconductor Nanocrystals for Optoelectronic and Energy Conversion Applications
Authors: Chen Dechao , Wang Aixiang , Buntine Mark A. , Jia Guohua
Published: July 2019

Colloidal semiconductor nanocrystals (NCs), especially cadmium (Cd)‐ and lead (Pb)‐containing ones, have been proved to be the promising materials for photoelectronic energy conversion applications. However, the high toxicity and cost of these materials restrict their widespread use. Zinc (Zn)‐containing colloidal semiconductor NCs are non‐/less toxic and environmentally friendly materials, manifesting in stimulating optical and electronic properties with relevance to a broad scope of applications including light‐emitting diodes (LEDs), sensors, photocatalysts, and more. In this Review, we elaborate on the shape control of Zn‐containing colloidal semiconductor NCs achieved by a variety of wet‐chemical synthetic approaches. Moreover, the formation of core‐shell, doped, and hybrid structures based on Zn‐containing colloidal semiconductor NCs allow for the optimization of their functionalities, which underpin stimulating photoelectronic energy conversion applications in quantum‐dot LEDs (QLEDs), photodetectors, and photocatalysis. Zn‐containing colloidal semiconductor NCs that combine the green chemistry with sustainable developments possess a bright future.
Impact of a Water‐Soluble Gallic Acid‐Based Dendrimer on the Color‐Stabilizing Mechanisms of Anthocyanins
Authors: Cruz Luís , Basílio Nuno , Mendoza Johan , Mateus Nuno , de Freitas Victor , Tawara Maun H. , Correa Juan , Fernandez‐Megia Eduardo
Published: July 2019

The interaction of two anthocyanins with a water‐soluble polyanionic dendrimer was studied through UV/Vis, stopped‐flow, and NMR spectroscopy. Cyanidin‐3‐glucoside (cy3glc) revealed a stronger interaction than malvidin‐3‐glucoside (mv3glc) at pH 1 according to their apparent association constants. A higher color increased was also obtained for cy3glc at pH 3.5 as a result of this stronger interaction. A high‐frequency chemical shift of the cy3glc aromatic protons suggest the formation of ionic pairs. The interaction parameters (K≈700 m−1, n≈295) indicated the binding of approximately two anthocyanin molecules by each sulfate group. The equilibrium and rate constants of cy3glc in the presence of dendrimer showed an increased stability of the flavylium cation and a higher protection of this species from hydration (pK′a and pKh increased almost one pH unit). The tuning and color stabilization of anthocyanins by using this dendrimer allow novel applications as colorimetric sensors for food packaging.
Beryllium‐Induced Conversion of Aldehydes
Authors: Müller Matthias , Buchner Magnus R.
Published: July 2019

Aldehydes play a key role in the human metabolism. Therefore, it is essential to know their reactivity with beryllium compounds in order to assess its effects in the body. The reactivity of simple aldehydes towards beryllium halides (F, Cl, Br, I) was studied through solution and solid‐state techniques and revealed distinctively different reactivities of the beryllium halides, with BeF2 being the least and BeI2 the most reactive. Rearrangement and aldol condensation reactions were observed and monitored by in situ NMR spectroscopy. Crystal structures of various compounds obtained by Be2+‐catalyzed cyclization, rearrangement, and aldol addition reactions or ligation of beryllium halides have been determined, including unprecedented one‐dimensional BeCl2 chains and the first structurally characterized example of an 1‐iodo‐alkoxide. Long‐term studies showed that only aldehydes without a β‐H can form stable beryllium complexes, whereas other aldehydes are oligo‐ and polymerized or decomposed by beryllium halides.
An Efficient Approach to Regio‐ and Stereodefined Fully‐Substituted Alkenylsilanes by Pd‐Catalyzed Allenic C(sp3)−H Oxidation
Authors: Zhu Can , Bäckvall Jan‐E.
Published: July 2019

A highly efficient palladium‐catalyzed functionalization of allenylsilanes to give regio‐ and stereodefined fully‐substituted alkenylsilanes has been developed. This oxidative coupling reaction showed good functional group compatibility with exclusive regio‐ and stereoselectivity. The pending olefin on the silyl group was shown to be an indispensable element for the initial allenic C(sp3)−H bond cleavage, and performs as the directing group to control the overall selectivity. The addition of substoichiometric amounts of Et3N was found to increase the reaction rate leading to a higher reaction yield. The reaction can be easily scaled up and applied for the late‐stage functionalization of natural products and pharmaceutical compounds, including amino acids and steroid derivatives. The newly introduced functional groups include aryl, alkynyl, and boryl groups. The highly strained four‐membered ring, silacyclobutene was obtained when B2pin2 was employed as the coupling partner. Mechanistic studies, including kinetic isotope effects, showed that the allenic C(sp3)−H bond cleavage is the rate‐limiting step.
Copper‐Catalyzed Oxidative Dearomatization of 2‐Naphthols via Etherification
Authors: Yi Ji‐Cheng , Wu Zhi‐Jie , You Shu‐Li
Published: July 2019

Summary of main observation and conclusion

Copper‐catalyzed intermolecular oxidative‐etherification type dearomatization reaction of 2‐naphthols was developed. With air as the terminal oxidant, the reaction proceeded in excellent yields under mild conditions. In addition, the reaction between two different naphthol substrates occurred smoothly. A series of multifunctionalized β‐naphthalenones, important scaffold existed widely in natural products and biologically active molecules, were synthesized efficiently.
Synthesis of Substituted 5′‐Aminoadenosine Derivatives and Evaluation of Their Inhibitory Potential toward CD73
Authors: Ghoteimi Rayane , Nguyen >Van Tai , Rahimova Rahila , Grosjean Felix , Cros‐Perrial Emeline , Uttaro Jean‐Pierre , Mathé Christophe , Chaloin Laurent , Jordheim Lars Petter , Peyrottes Suzanne
Published: July 2019

Derivatives of 5′‐aminoadenosine containing methyl carboxylate, methyl phosphonate, gem‐bisphosphonate, bis(methylphosphonate), and α‐carboxylmethylphosphonate or phosphonoacetate moieties were synthesized from key intermediate 5′‐aminonucleoside. These nucleotide analogues were envisaged as 5′‐mono‐ or diphosphate nucleoside mimics. All compounds were evaluated for CD73 inhibition in a cell‐based assay (MDA‐MB‐231) and toward the purified recombinant protein. Most of them failed to reach significant inhibition of AMP hydrolysis by CD73 at 100 μm. Among the new compounds, the most interesting candidates, 5 (5′‐deoxy‐5′‐N‐phosphonomethyladenosine) and 7 (5′‐deoxy‐5′‐N‐(ethoxyphosphorylacetate)adenosine), inhibited recombinant CD73 by 36 and 46 % and cellular CD73 by 61 and 45 % at 100 μm, respectively. Molecular modeling partially explains this lack of activity, as the initially predicted docking scores had been encouraging, especially for compound 9.
The Impact of Alkyl‐Chain Purity on Lipid‐Based Nucleic Acid Delivery Systems – Is the Utilization of Lipid Components with Technical Grade Justified?
Authors: Pawlowska Dorota , Janich Christopher , Langner Andreas , Dobner Bodo , Wölk Christian , Brezesinski Gerald
Published: July 2019

The physicochemical properties and transfection efficacies of two samples of a cationic lipid have been investigated and compared in 2D (monolayers at the air/liquid interface) and 3D (aqueous bulk dispersions) model systems using different techniques. The samples differ only in their chain composition due to the purity of the oleylamine (chain precursor). Lipid 8 (using the oleylamine of technical grade for cost‐efficient synthesis) shows lateral phase separation in the Langmuir layers. However, the amount of attached DNA, determined by IRRAS, is for both samples the same. In 3D systems, lipid 8 p forms cubic phases, which disappear after addition of DNA. At physiological temperatures, both lipids (alone and in mixture with cholesterol) assemble to lamellar aggregates and exhibit comparable DNA delivery efficiency. This study demonstrates that non‐lamellar structures are not compulsory for high transfection rates. The results legitimate the utilization of oleyl chains of technical grade in the synthesis of cationic transfection lipids.
Machine learning approach for secure communication in wireless video sensor networks against denial‐of‐service attacks
Authors: Ramesh Swaminathan , Yaashuwanth Calpakkam , Muthukrishnan Bala Anand
Published: July 2019

Mobile ad hoc networks (MANETs) own a flexible framework with the absence of a server, where conventional security components fail to compensate the level of MANET security conditions since it is confined to a particular environment, its data transfer potential, and battery and memory constrains. MANET provides a well‐grounded path and an efficiency in communication, but the confidentiality of the trust parameters remains a great challenge since it may be overheard by the impostor. This demands the need of exchanging the encrypted mathematical values. The proposed machine learning security paradigm provides firm and trustworthy network in spite of establishment over additional network platform. The QoS is improved through support vector machine for denial‐of‐service attack. The node has to be clustered to accomplish its respective task. The clustering is done with the help of LEACH protocol, where cluster head and Cluster member are fixed to transfer the data in the network. Low Energy adaptive clustering heirarchy (LEACH) propagates energy to abstain from draining of battery and malignant network. A secure framework is built along with encryption and decoding to protect from denial‐of‐service attack. Acknowledgement‐based flooding attack has been focused with the help of support vector machine algorithm. The messages are encoded in from the source node and coded again during transmission phase to obtain the original message. Defending the traditional methodologies, the proposed work provides excellent QoS when compared and tested with other protocols. The results obtained ensure its efficiency when support vector machine technique is combined with encryption scheme.
Genetic structure at three spatial scales is consistent with limited philopatry in Ricord's Rock Iguanas (Cyclura ricordii)
Authors: Carreras‐De León Rosanna , Pasachnik Stesha A. , Gerber Glenn P. , Brooks Christopher P. , Rupp Ernst , Welch Mark E.
Published: July 2019

Cyclura ricordiiis an endemic iguana from Hispaniola Island and is threatened on the IUCN Red List. The main threats are predation by introduced mammals, habitat destruction, and hunting pressure. The present study focused on two nesting sites from Pedernales Province in the Dominican Republic. The hypothesis that natal philopatry influences dispersal and nest‐site selection was tested. Monitoring and sampling took place in 2012 and 2013. Polymorphic markers were used to evaluate whether natal philopatry limits dispersal at multiple spatial scales. Ripley'sKrevealed that nests were significantly clustered at multiple scales, when both nesting sites were considered and within each nesting site. This suggests a patchy, nonrandom distribution of nests within nest sites. Hierarchical AMOVA revealed that nest‐site aggregations did not explain a significant portion of genetic variation within nesting sites. However, a small but positive correlation between geographic and genetic distance was detected using a Mantel's test. Hence, the relationship between geographic distance and genetic distance among hatchlings within nest sites, while detectable, was not strong enough to have a marked effect on fine‐scale genetic structure. Spatial and genetic data combined determined that the nesting sites included nesting females from multiple locations, and the hypothesis of “natal philopatry” was not supported because females nesting in the same cluster were no more closely related to each other than to other females from the same nesting site. These findings imply that nesting aggregations are more likely associated with cryptic habitat variables contributing to optimal nesting conditions.
Species‐level repertoire size predicts a correlation between individual song elaboration and reproductive success
Authors: Robinson Cristina M. , Creanza Nicole
Published: July 2019

Birdsong has long been considered a sexually selected trait that relays honest information about male quality, and laboratory studies generally suggest that female songbirds prefer larger repertoires. However, analysis of field studies across species surprisingly revealed a weak correlation between song elaboration and reproductive success, and it remains unknown why only certain species show this correlation in nature. Taken together, these studies suggest that females in numerous species can detect and prefer larger repertoires in a laboratory setting, but larger individual repertoires correlate with reproductive success only in a subset of these species. This prompts the question: Do the species that show a stronger correlation between reproductive success and larger individual repertoires in nature have anything in common? In this study, we test whether between‐species differences in two song‐related variables—species average syllable repertoire size and adult song stability over time—can be used to predict the importance of individual song elaboration in reproductive success within a species. Our cross‐species meta‐analysis of field studies revealed that species with larger average syllable repertoire sizes exhibited a stronger correlation between individual elaboration and reproductive success than species with smaller syllable repertoires. Song stability versus plasticity in adulthood provided little predictive power on its own, suggesting that the putative correlation between repertoire size and age in open‐ended learners does not explain the association between song elaboration and reproductive success.
Biomass‐Derived Carbon Dots and Their Applications
Authors: Meng Weixue , Bai Xue , Wang Boyang , Liu Zhongyi , Lu Siyu , Yang Bai
Published: July 2019

Carbon dots (CDs) have received much attention due to their superior properties including water solubility, low toxicity, biocompatibility, small size, fluorescence, and ease of modification. The use of a more environmentally friendly method to prepare high‐quality CDs is still an urgent question waiting for solve. The use of renewable, inexpensive, and green biomass resources not only meets the urgent need for large‐scale synthesis biomass CDs (BCDs), but also promotes the development of sustainable applications. In this article, we summarize the representative methods for synthesizing BCDs in green and simple ways using biomass as a carbon source, including hydrothermal carbonization, and microwave, pyrolysis. The prepared BCDs have a uniform particle size distribution and a relatively high throughput, which provide a method to scale up industrial production. Moreover, the integration of specific optical properties, that is, tunable photoluminescence and up‐photoluminescence, has led to remarkable use in bioimaging, sensing, and drug delivery. But the current review is not particularly comprehensive for BCDs. Therefore, we now provide a review focusing on the synthesis, properties, and recent advances in BCDs in biosensing, bioimaging, optoelectronics, and catalytic applications.
Regional differences in heart failure hospitalizations, mortality, and readmissions in Slovenia 2004–2012
Authors: Omersa Daniel , Erzen Ivan , Lainscak Mitja , Farkas Jerneja
Published: July 2019

Aims

Heart failure (HF) burden is displaying significant inter‐regional differences within Europe and within countries. Due to limited data focusing on regional differences, our aim was to evaluate HF hospitalizations, readmissions, and mortality burden in Slovenian statistical regions.

Methods and results

The Slovenian National Hospitalization Discharge Registry was searched for HF hospitalizations in patients 20 years or over in the period 2004–12. Annual sex and age‐standardized HF hospitalizations, mortality, and HF readmissions rates were calculated for Slovenia and for each Slovenian statistical region. Trends were evaluated using ANOVA. Multiple mixed effect logistic regression models, which included statistical region, admission year, sex, age, intensive care unit treatment, and co‐morbidities as a fixed effect and hospital identifier as a random effect, were calculated for mortality and readmissions. Overall, 156 859 HF hospitalizations (55 522 where HF was coded as a main diagnosis and 43 606 as first HF hospitalizations) were recorded. Annual standardized rates varied considerably between statistical regions for main (220–511) and first HF hospitalization (392–721), 30 day (12.6–27.1) and 1 year mortality (66–117), and 30 day (31–80.8) and 1 year readmission (99–24) (per 100 000 patient years in 2012). Yearly decline in HF hospitalization rates was seen for national main (3.6; 0.001) and first (8.4; 0.083) HF hospitalizations, while individual regional main and first HF hospitalization trends mostly did not reach statistical significance. No relevant differences in mortality and readmission endpoints for statistical regions were seen when adjusted for patient demographics and specific co‐morbidities.

Conclusions

Significant regional differences in standardized HF hospitalization, mortality, and readmissions between the regions were seen. There were no differences in mortality and readmissions between statistical regions for individual similar patients.
cRh‐Catalyzed Hydroformylation of Divinylglycol: An Effective Way to Access 2,7‐Dioxadecalin‐3,8‐diol
Authors: Bricout Hervé , Vanbésien Théodore , Wei Muh‐Mei , Billamboz Muriel , Len Christophe , Monflier Eric , Hapiot Frédéric
Published: July 2019

Obtained from glycerol, divinylglycol (DVG) is a promising bio‐based building block. Upon hydroformylation of DVG, a very complex mixture of different products is obtained. Unexpectedly, the addition of chloroform at 0 °C on this mixture provokes the selective precipitation of 2,7‐dioxadecalin‐3,8‐diol, an interesting bicyclic bis‐hemiacetal.
Electrochemical Sensor Based on Casein and Carbon Black for Bisphenol A Detection
Authors: Vieira Jodar Letícia , Orzari Luiz Otávio , Storti Ortolani Túlio , Assumpção Mônica H. M. T. , Vicentini Fernando C. , Janegitz Bruno C.
Published: July 2019

Bisphenol A (BPA) is an environmental endocrine disrupting chemical, which can lead to various adverse health effects. Aiming to develop effective tools for the detection of BPA, this work reports a low cost and stable film based on casein (CAS) and Carbon Black (CB). The proposed material (CAS‐CB) showed structures of CAS surrounded by CB agglomerates observed by Scanning Electron Microscopy while Fourier Transform Infrared Spectroscopy analysis illustrated characteristic bands of casein. Cyclic Voltammetry (CV) and linear sweep voltammetry (LSV) were used to investigate the electrochemical behavior of BPA using the CAS‐CB. Under optimal conditions, LSV detection presented a limit of detection of 0.25 μmol L−1 in a linear range from 0.49 to 24 μmol L−1. Additionally, the working electrode (GC) modified by the proposed film (CAS‐CB) was applied for BPA sensing in environmental and milk samples. The results showed recoveries between 95.4 to 114 % attesting the efficiency of this new material, which has simplicity in the preparation, high conductivity, and adsorption capability.
First comprehensive view on a magnetic separation based protein purification processes: From process development to cleaning validation of a GMP‐ready magnetic separator
Authors: Ebeler Moritz , Pilgram Florian , Wellhöfer Thomas , Frankenfeld Katrin , Franzreb Matthias
Published: July 2019

Magnetic separation processes are known as integrated bioanalytical protein purification method since decades and are well described. However, use of magnetic separation processes in a regulated industrial production environment has been prevented by the lack of suitable process equipment and prejudice against the productivity of the process and its qualification for cleaning‐in‐place operation. With the aim of overcoming this prejudice, a comprehensive process development approach is presented, based on a GMP‐compliant magnetic separator, including an optimization of the batch adsorption process, implementation into a technical‐scale, and the development and validation of cleaning routines for the device. By the implementation of a two‐step counter‐current binding process, it was possible to raise the yields of the magnetic separation process even for very low concentrated targets in a vast surplus of competing proteins, like the hormone equine chorionic gonadotropin in serum, from 74% to over 95%. For the validation of the cleaning process, a direct surface swabbing method combined with a total organic carbon analysis was established for the determination of two model contaminants. The cleanability of the process equipment was proven for both model contaminants by reliably meeting the 10 ppm criteria.