bluuebunny/crossref_metadata_2025 huggingface dataset:
A Virtual geometric morphometric approach to the quantification of long bone bilateral asymmetry and cross‐sectional shape
Authors: Wilson Laura A.B. , Humphrey Louise T.
Published: July 2015

Objective

The widespread use of three‐dimensional digitization means that models of whole bone geometry are routinely captured for many applications in virtual anthropology. In this article, we test whether a geometric morphometric (GMM) approach can be used to accurately quantify directional bilateral asymmetry in cross‐sectional shape using virtual bone models.

Methods

We introduce a method to (1) orient virtual long bone models and extract cross sections and (2) collect GMM landmarks to analyze cross‐sectional shape. Landmark data, captured using polar radii, were analyzed for an example study set of paired humeri from Andaman Islanders sampled at 35%, 50%, and 65% locations.

Results

The GMM method can (1) detect significant differences in left and right cross‐sectional shape and (2) allow the directionality of shape change (distribution of bone from centroid) to be evaluated in the context of whole outline shape and in relation to the axis of maximum bending rigidity. The protocol may be used with models created from laser (surface) scan or computed tomography (CT) scan data, and applied to cross‐sectional images that were collected using periosteal molding techniques.

Conclusions

The results demonstrate directional bilateral asymmetry in shape, but do not recover the same signal for size measurements. Our method offers a pathway to quantify both the pattern of variation in shape and the relationship between size and shape variation, opening new questions about how those patterns manifest over ontogeny, change temporally or differ in relation to the nature and intensity of the activity, and bone loading conditions. Am J Phys Anthropol 158:541–556, 2015. © 2015 Wiley Periodicals, Inc.
Ancient marine hunter‐gatherers from Patagonia and Tierra Del Fuego: Diversity and differentiation using uniparentally inherited genetic markers
Authors: de la Fuente Constanza , Galimany Jacqueline , Kemp Brian M. , Judd Kathleen , Reyes Omar , Moraga Mauricio
Published: July 2015

Objectives

The human population history from Patagonia and Tierra del Fuego has been of great interest in the context of the American peopling. Different sources of evidence have contributed to the characterization of the local populations, but some main questions about their history remain unsolved. Among the native populations, two marine hunter‐gatherers groups inhabited the Patagonian channels below the 478S: Kawéskar and Yámana. Regardless of their geographical proximity and cultural resemblance, their languages were mutually unintelligible. In this study we aim to evaluate the genetic diversity of uniparental genetic markers in both groups and to test if there is a high genetic differentiation between them, mirroring their linguistic differences.

Material and Methods

Ancient DNA was extracted from 37 samples from both populations. We compared their genetic variability of their mitochondrial lineages and Y‐STR as well as with other modern native populations from the area and further north.

Results and Discussion

We observed an important differentiation in their maternal lineages: while Kawéskar shows a high frequency of D (80%), Yámana shows a high frequency of C (90%). The analysis of paternal lineages reveals the presence of only Q1a2a1a1 and little variation was found between individuals. Both groups show very low levels of genetic diversity compared with modern populations. We also notice shared and unique mitochondrial DNA variants between modern and ancient samples of Kawéskar and Yámana. Am J Phys Anthropol 158:719–729, 2015. © 2015 Wiley Periodicals, Inc.
The skeletal manifestation of malaria: An epidemiological approach using documented skeletal collections
Authors: Smith‐Guzmán Nicole E.
Published: July 2015

Objectives

Recent studies in paleopathology have shown promise in associating some skeletal lesions with malarial infection. However, malaria's skeletal manifestation has never been confirmed using a large clinical reference sample from an endemic area for malaria with known individual causes of death.

Materials and Methods

To pinpoint evidence of malaria infection on ancient skeletal remains, this study uses an epidemiological approach to compare skeletal lesions in a modern reference sample of 98 individuals from Uganda, where malaria is holoendemic, to a similar modern sample of 106 individuals from a malaria‐free area.

Results

Five porous skeletal lesions are identified that appear more frequently in the endemic area population, especially in anemic individuals. These appear on the cranium, vertebral column, and humeral and femoral necks. Periostitis also associates strongly with individuals in the endemic population; however, linear enamel hypoplasias show an inverse association. The identified lesions are tested for their association with each other, and then tested individually for their diagnostic power through measures of sensitivity and specificity. A diagnostic outcome algorithm is formed from the remaining skeletal lesions and their inter‐lesion associations.

Discussion

Several etiological explanations for the characteristic malarial skeletal lesions are explored, including severe malarial anemia, an imbalance in bone remodeling, and extramedullary erythropoiesis. The importance of careful differential diagnoses between other infectious and noninfectious causes of these lesions is discussed, including the potential for coinfection of malaria with other infectious diseases. The findings of this study are pivotal in establishing diagnostic criteria by which we can identify the prevalence and impact of malaria on past populations. Am J Phys Anthropol 158:624–635, 2015. © 2015 Wiley Periodicals, Inc.
The effect of nasal irrigation formulation on the antimicrobial activity of nasal secretions
Authors: Woods Charmaine M. , Tan Sophia , Ullah Shahid , Frauenfelder Claire , Ooi Eng H. , Carney A. Simon
Published: July 2015

Background

Saline‐based irrigation solutions are evidence‐based rhinological treatments; however, the formulation of these solutions could theoretically alter the function of innate antimicrobial peptides. The aim of this study was to determine if the antimicrobial activity of normal human nasal secretions in vivo is altered by commercially available large volume irrigation solutions.

Methods

Minimally manipulated sinonasal secretions were collected from patients with chronic rhinosinusitis (CRS; n = 10) and normal healthy volunteers (n = 20). In a subset of control patients (n = 10) secretions were collected prior to, and at 1 hour, 6 hours, and 24 hours after nasal irrigation with 4 commercial irrigation solutions. Lysozyme and lactoferrin levels were analyzed and the antimicrobial activity of secretions determined using a radial diffusion assay.

Results

The antimicrobial activity of nasal secretions was reduced in CRS patients compared to healthy volunteers (p < 0.01), but there was no significant difference in antimicrobial peptide concentrations. Isotonic nasal irrigation reduced lysozyme and lactoferrin levels, which returned to baseline levels by 6 hours; in addition to a sustained decrease in antimicrobial activity before returning to baseline at 24 hours. Low‐salt solution stimulated peptide secretion by approximately 40% at 6 hours and 24 hours, but produced a transient decrease in antimicrobial activity, returning to baseline levels by 6 hours. Hypertonic solution initially decreased lysozyme and lactoferrin levels but maintained baseline levels of antimicrobial activity and increased peptide secretion by approximately 30% at 24 hours.

Conclusion

The formulation of nasal irrigation solutions significantly affects the measured levels and functionality of sinonasal antimicrobial peptides.
Directional Materials—Nanoporous Organosilica Monoliths with Multiple Gradients Prepared Using Click Chemistry
Authors: Schachtschneider Andreas , Wessig Martin , Spitzbarth Martin , Donner Adrian , Fischer Christian , Drescher Malte , Polarz Sebastian
Published: July 2015

The existence of more than one functional entity is fundamental for materials, which are desired of fulfilling complementary or succeeding tasks. Whereas it is feasible to make materials with a homogeneous distribution of two different, functional groups, cases are extremely rare exhibiting a smooth transition from one property to the next along a defined distance. We present a new approach leading to high‐surface area solids with functional gradients at the microstructural level. Periodically ordered mesoporous organosilicas (PMOs) and aerogel‐like monolithic bodies with a maximum density of azide groups were prepared from a novel sol–gel precursor. The controlled and fast conversion of the azide into numerous functions by click chemistry is the prerequisite for the implementation of manifold gradient profiles. Herein we discuss materials with chemical, optical and structural gradients, which are interesting for all applications requiring directionality, for example, chromatography.
Hydrothermal Synthesis of Unique Hollow Hexagonal Prismatic Pencils of Co3V2O8⋅n H2O: A New Anode Material for Lithium‐Ion Batteries
Authors: Wu Fangfang , Xiong Shenglin , Qian Yitai , Yu Shu‐Hong
Published: July 2015

Hollow structures of transition‐metal oxides, particularly mixed‐metal oxides, could be promising for various applications such as lithium‐ion batteries (LIBs). Compared to the synthesis of metal oxide hollow spheres by the template method, non‐spherical metal oxide hollow hexagonal polyhedra have not been developed to date. Herein, we report the controlled hydrothermal synthesis of a new phase of Co3V2O8⋅n H2O hollow hexagonal prismatic pencils (HHPPs), which is composed of uniform structural units. By varying the amount of NaOH in the presence of NH4+ and without any template or organic surfactant, the hexagonal prismatic pencils gradually transform from solid into hollow structures, with sizes varying from 5 to 20 μm. The structure of pencils can be preserved only in a limited range of the molar ratio of OH−/NH4+. As a new anode material for LIBs, such hollow pencils exhibit impressive lithium storage properties with high capacity, good cycling stability, and superior rate capability.
Ein universeller Zugang zu Nucleobasen‐modifizierten Aptameren
Authors: Tolle Fabian , Brändle Gerhard M. , Matzner Daniel , Mayer Günter
Published: July 2015

Wir beschreiben eine neue und vielseitige Methode, um die chemische Diversität von Nucleinsäurebibliotheken modular zu erweitern. Dies ermöglicht den Zugang zu Nucleobasen‐modifizierten Aptameren mit einer bisher unerreicht hohen Affinität und Spezifität für ihre Zielstrukturen. Die Wiedereinführung der Modifikation nach der enzymatischen Replikation gewährt dabei einen eleganten Zugang zu einer Vielzahl von chemischen Gruppen. Die breite Anwendbarkeit, die sich nicht auf eine einzige Modifikation beschränkt, wird in Zukunft In‐vitro‐Selektionsprozesse rasant voranbringen und weitere Aptamere für viele bis dato nicht adressierbare Zielstrukturen generieren.
Total Syntheses and Biological Evaluation of Both Enantiomers of Several Hydroxylated Dimeric Nuphar Alkaloids
Authors: Korotkov Alexander , Li Hui , Chapman Charles W. , Xue Haoran , MacMillan John B. , Eastman Alan , Wu Jimmy
Published: July 2015

Herein, we describe the first total syntheses of five members of the dimeric nuphar alkaloids: (+)‐6,6′‐dihydroxythiobinupharidine (+)‐1 a, (+)‐6‐hydroxythiobinupharidine (+)‐1 b, (−)‐6,6′‐dihydroxythionuphlutine (−)‐2 a, (−)‐6,6′‐dihydroxyneothiobinupharidine (−)‐3 a, and (+)‐6,6′‐dihydroxyneothionuphlutine (+)‐4 a. The latter two have not been found in nature. We have also made each of their enantiomers (−)‐1 a–b, (+)‐2 a, (+)‐3 a, and (−)‐4 a. The key step in these syntheses was the dimerization of an α‐aminonitrile (a hydrolytically stable surrogate for its corresponding hemiaminal) with chiral Lewis acid complexes. We have also reassigned the literature structures of (+)‐1 a–1 b—for those instances in which the NMR spectra were obtained in CD3OD—to their corresponding CD3O‐adducts. Our efforts provide for the first time apoptosis data for (−)‐3 a, (+)‐4 a, and all five non‐natural enantiomers prepared. The data indicate high apoptotic activity regardless of the enantiomer or relative stereochemical configuration at C7 and C7′.
Palladium‐Catalyzed Hydroamidocarbonylation of Olefins to Imides
Authors: Li Haoquan , Dong Kaiwu , Neumann Helfried , Beller Matthias
Published: July 2015

Carbonylation reactions allow the efficient synthesis of all kinds of carbonyl‐containing compounds. Here, we report a straightforward synthesis of various imides from olefins and CO for the first time. The established hydroamidocarbonylation reaction affords imides in good yields (up to 90 %) and with good regioselectivity (up to 99:1) when applying different alkenes and amides. The synthetic potential of the method is highlighted by the synthesis of Aniracetam by intramolecular hydroamidocarbonylation.
Regioselective and 1,2‐cis‐α‐Stereoselective Glycosylation Utilizing Glycosyl‐Acceptor‐Derived Boronic Ester Catalyst
Authors: Nakagawa Akira , Tanaka Masamichi , Hanamura Shun , Takahashi Daisuke , Toshima Kazunobu
Published: July 2015

Regioselective and 1,2‐cis‐α‐stereoselective glycosylations using 1α,2α‐anhydro glycosyl donors and diol glycosyl acceptors in the presence of a glycosyl‐acceptor‐derived boronic ester catalyst. The reactions proceed smoothly to give the corresponding 1,2‐cis‐α‐glycosides with high stereo‐ and regioselectivities in high yields without any further additives under mild reaction conditions. In addition, the present glycosylation method was successfully applied to the synthesis of an isoflavone glycoside.
Revealing the Macromolecular Targets of Fragment‐Like Natural Products
Authors: Rodrigues Tiago , Reker Daniel , Kunze Jens , Schneider Petra , Schneider Gisbert
Published: July 2015

Fragment‐like natural products were identified as ligand‐efficient chemical matter for hit‐to‐lead development and chemical‐probe discovery. Relying on a computational method using a topological pharmacophore descriptor and a drug database, several macromolecular targets from distinct protein families were expeditiously retrieved for structurally unrelated chemotypes. The selected fragments feature structural dissimilarity to the reference compounds and suitable target affinity, and they offer opportunities for chemical optimization. Experimental confirmation of hitherto unknown macromolecular targets for the selected molecules corroborate the usefulness of the computational approach and suggests broad applicability to chemical biology and molecular medicine.
Herstellung von festen, substituierten Allylzinkreagentien und deren Reaktionen mit Elektrophilen
Authors: Ellwart Mario , Knochel Paul
Published: July 2015

Die Reaktion von verschiedenen allylischen Chloriden und Bromiden mit Zinkstaub in der Gegenwart von Lithiumchlorid und Magnesiumpivalat (Mg(OCOtBu)2) in THF führt zu allylischen Zinkreagentien, welche nach Entfernen des Lösungsmittels als feste Zinkreagentien erhalten werden, die eine exzellente thermische Stabilität aufweisen. Diese allylischen Reagentien können sowohl in Pd‐katalysierten Kreuzkupplungen mit PEPPSI‐IPent, als auch in regio‐ und stereoselektiven Additionen an aromatische Ketone und Aldehyde verwendet werden. Acylierungen mit verschiedenen Säurechloriden führen regioselektiv zu den entsprechenden homoallylischen Ketonen, wobei die neue C‐C‐Bindung immer an der sterisch stärker gehinderten Seite gebildet wird.
Amphiphilic Nanoparticles Control the Growth and Stability of Lipid Bilayers with Open Edges
Authors: Shin Sun Hae Ra , Lee Hee‐Young , Bishop Kyle J. M.
Published: July 2015

Molecular amphiphiles self‐assemble in polar media to form ordered structures such as micelles and vesicles essential to a broad range of industrial and biological processes. Some of these architectures such as bilayer sheets, helical ribbons, and hollow tubules are potentially useful but inherently unstable owing to the presence of open edges that expose the hydrophobic bilayer core. Here, we describe a strategy to stabilize open bilayer structures using amphiphilic nanoparticle surfactants that present mixtures of hydrophilic and hydrophobic ligands on their surface. We observe that these particles bind selectively to the open edge of bilayer membranes to stabilize otherwise transient amphiphile assemblies. We show how such particles can precisely control the size of lipid tubules, how they can inhibit the formation of undesirable assemblies such as gallstone precursors, and how they can stabilize free‐floating lipid microdiscs.
A Small‐Molecule Probe for Selective Profiling and Imaging of Monoamine Oxidase B Activities in Models of Parkinson’s Disease
Authors: Li Lin , Zhang Cheng‐Wu , Ge Jingyan , Qian Linghui , Chai Bing‐Han , Zhu Qing , Lee Jun‐Seok , Lim Kah‐Leong , Yao Shao Q.
Published: July 2015

The design of the first dual‐purpose activity‐based probe of monoamine oxidase B (MAO‐B) is reported. This probe is highly selective towards MAO‐B, even at high MAO‐A expression levels, and could sensitively report endogenous MAO‐B activities by both in situ proteome profiling and live‐cell bioimaging. With a built‐in imaging module as part of the probe design, the probe was able to accomplish what all previously reported MAO‐B imaging probes failed to do thus far: the live‐cell imaging of MAO‐B activities without encountering diffusion problems.
A Single Stereodynamic Center Modulates the Rate of Self‐Assembly in a Biomolecular System
Authors: Zhang Yitao , Malamakal Roy M. , Chenoweth David M.
Published: July 2015

Chirality is a property of asymmetry important to both physical and abstract systems. Understanding how molecular systems respond to perturbations in their chiral building blocks can provide insight into diverse areas such as biomolecular self‐assembly, protein folding, drug design, materials, and catalysis. Despite the fundamental importance of stereochemical preorganization in nature and designed materials, the ramifications of replacing chiral centers with stereodynamic atomic mimics in the context of biomolecular systems is unknown. Herein, we demonstrate that replacement of a single amino acid stereocenter with a stereodynamic nitrogen atom has profound consequences on the self‐assembly of a biomolecular system. Our results provide insight into how the fundamental biopolymers of life would behave if their chiral centers were not configurationally stable, highlighting the vital importance of stereochemistry as a pre‐organizing element in biomolecular folding and assembly events.
A Single Enzyme Transforms a Carboxylic Acid into a Nitrile through an Amide Intermediate
Authors: Nelp Micah T. , Bandarian Vahe
Published: July 2015

The biosynthesis of nitriles is known to occur through specialized pathways involving multiple enzymes; however, in bacterial and archeal biosynthesis of 7‐deazapurines, a single enzyme, ToyM, catalyzes the conversion of the carboxylic acid containing 7‐carboxy‐7‐deazaguanine (CDG) into its corresponding nitrile, 7‐cyano‐7‐deazaguanine (preQ0). The mechanism of this unusual direct transformation was shown to proceed via the adenylation of CDG, which activates it to form the newly discovered amide intermediate 7‐amido‐7‐deazaguanine (ADG). This is subsequently dehydrated to form the nitrile in a process that consumes a second equivalent of ATP. The authentic amide intermediate is shown to be chemically and kinetically competent. The ability of ToyM to activate two different substrates, an acid and an amide, accounts for this unprecedented one‐enzyme catalysis of nitrile synthesis, and the differential rates of these two half reactions suggest that this catalytic ability is derived from an amide synthetase that gained a new function.
White‐Light Emission from an Integrated Upconversion Nanostructure: Toward Multicolor Displays Modulated by Laser Power
Authors: Zhang Cheng , Yang Liang , Zhao Jun , Liu Bianhua , Han Ming‐Yong , Zhang Zhongping
Published: July 2015

The white backlight in displays is generated by optimizing the proportions of individual emitters with different wavelengths by variations in materials composition, phase, and structure. Color pixels usually result from the separation of white light or the excitation with multiwavelength or multipulse sources. However, it is a challenge to develop a material that comprises a single structure and emits over the full visible spectrum, but where the emission wavelengths can be controlled by a simple excitation source. Herein, we report an upconversion nanostructure that incorporates several lanthanide ions in the same core@shell@shell structure. The combination of multiple narrow spectral bands results in the emission of white light. The emission colors can be tuned by changing the excitation power density, which manipulates the photon transfer pathways. Applications such as flat‐panel displays and imaging have been demonstrated.
Synthesis of 3,4,5‐Trisubstituted Isoxazoles from Morita–Baylis–Hillman Acetates by an NaNO2/I2‐Mediated Domino Reaction
Authors: Dighe Shashikant U. , Mukhopadhyay Sushobhan , Kolle Shivalinga , Kanojiya Sanjeev , Batra Sanjay
Published: July 2015

An efficient NaNO2/I2‐mediated one‐pot transformation of Morita–Baylis–Hillman (MBH) acetates into alkyl 3‐nitro‐5‐(aryl/alkyl)isoxazole‐4‐carboxylates is described. In a cascade event, initial Michael addition of NaNO2 to the MBH acetate furnishes the allylnitro intermediate which undergoes I2‐catalyzed oxidative α‐CH nitration of the nitromethyl subunit followed by [3+2] cycloaddition to afford the title compounds. Structural elaborations of these highly substituted isoxazoles by SNAr reactions and hydrogenolysis allows access to useful products.
X‐ray Radiation‐Controlled NO‐Release for On‐Demand Depth‐Independent Hypoxic Radiosensitization
Authors: Fan Wenpei , Bu Wenbo , Zhang Zhen , Shen Bo , Zhang Hui , He Qianjun , Ni Dalong , Cui Zhaowen , Zhao Kuaile , Bu Jiwen , Du Jiulin , Liu Jianan , Shi Jianlin
Published: July 2015

Multifunctional stimuli‐responsive nanotheranostic systems are highly desirable for realizing simultaneous biomedical imaging and on‐demand therapy with minimized adverse effects. Herein, we present the construction of an intelligent X‐ray‐controlled NO‐releasing upconversion nanotheranostic system (termed as PEG‐USMSs‐SNO) by engineering UCNPs with S‐nitrosothiol (R‐SNO)‐grafted mesoporous silica. The PEG‐USMSs‐SNO is designed to respond sensitively to X‐ray radiation for breaking down the SN bond of SNO to release NO, which leads to X‐ray dose‐controlled NO release for on‐demand hypoxic radiosensitization besides upconversion luminescent imaging through UCNPs in vitro and in vivo. Thanks to the high live‐body permeability of X‐ray, our developed PEG‐USMSs‐SNO may provide a new technique for achieving depth‐independent controlled NO release and positioned radiotherapy enhancement against deep‐seated solid tumors.
An Enantioselective Synthesis of Spirobilactams through Copper‐Catalyzed Intramolecular Double N‐Arylation and Phase Separation
Authors: Liu Jianguang , Tian Yingying , Shi Jialing , Zhang Shasha , Cai Qian
Published: July 2015

Spirobicyclic structures are versatile building blocks for functional chiral molecules. An enantioselective synthesis of chiral spirobilactams via a copper‐catalyzed double N‐arylation was developed. Amplification of solution ee by in situ precipitation of the racemate was observed with this method and enantioenriched spirobilactams were obtained with excellent ee values through simple solid–solution phase separation.
Switchable Lipids: Conformational Change for Fast pH‐Triggered Cytoplasmic Delivery
Authors: Viricel Warren , Mbarek Amira , Leblond Jeanne
Published: July 2015

We report the use of switchable lipids to improve the endosomal escape and cytosolic delivery of cell‐impermeable compounds. The system is based on a conformational reorganization of the lipid structure upon acidification, as demonstrated by NMR spectroscopic studies. When incorporated in a liposome formulation, the switchable lipids triggered bilayer destabilization through fusion even in the presence of poly(ethylene glycol). We observed 88 % release of sulforhodamine B in 15 min at pH 5, and the liposome formulations demonstrated high stability at pH 7.4 for several months. By using sulforhodamine B as a model of a highly polar drug, we demonstrated fast cytosolic delivery mediated by endosomal escape in HeLa cells, and no toxicity.
Rattling in the Quadruple Perovskite CuCu3V4O12
Authors: Akizuki Yasuhide , Yamada Ikuya , Fujita Koji , Taga Kazuya , Kawakami Takateru , Mizumaki Masaichiro , Tanaka Katsuhisa
Published: July 2015

Of particular interest is a peculiar motion of guest atoms or ions confined to nanospace in cage compounds, called rattling. While rattling provides unexplored physical properties through the guest–host interactions, it has only been observed in a very limited class of materials. Herein, we introduce an A‐site‐ordered quadruple perovskite, CuCu3V4O12, as a new family of cage compounds. This novel AA′3B4O12‐type perovskite has been obtained by a high‐pressure synthesis technique and structurally characterized to have cubic Im$\bar 3$ symmetry with an ionic model of Cu2+Cu2+3V4+4O12. The thermal displacement parameter of the A‐site Cu2+ ion is as large as Uiso≈0.045 Å2 at 300 K, indicating its large‐amplitude thermal oscillations in the oversized icosahedral cages. Remarkably, the presence of localized phonon modes associated with rattling of the A‐site Cu2+ ion manifests itself in the low‐temperature specific heat data. This work sheds new light on the structure–property relations in perovskites.
Waterproof Alkyl Phosphate Coated Fluoride Phosphors for Optoelectronic Materials
Authors: Nguyen Hoang‐Duy , Lin Chun Che , Liu Ru‐Shi
Published: July 2015

A facile approach for coating red fluoride phosphors with a moisture‐resistant alkyl phosphate layer with a thickness of 50–100 nm is reported. K2SiF6:Mn4+ particles were prepared by co‐precipitation and then coated by esterification of P2O5 with alcohols (methanol, ethanol, and isopropanol). This route was adopted to encapsulate the prepared phosphors using transition‐metal ions as cross‐linkers between the alkyl phosphate moieties. The coated phosphor particles exhibited a high water tolerance and retained approximately 87 % of their initial external quantum efficiency after aging under high‐humidity (85 %) and high‐temperature (85 °C) conditions for one month. Warm white‐light‐emitting diodes that consisted of blue InGaN chips, the prepared K2SiF6:Mn4+ phosphors, and either yellow Y3Al5O12:Ce3+ phosphors or green β‐SiAlON: Eu2+ phosphors showed excellent color rendition.
Frustration Sculpts the Early Stages of Protein Folding
Authors: Di Silvio Eva , Brunori Maurizio , Gianni Stefano
Published: July 2015

The funneled energy landscape theory implies that protein structures are minimally frustrated. Yet, because of the divergent demands between folding and function, regions of frustrated patterns are present at the active site of proteins. To understand the effects of such local frustration in dictating the energy landscape of proteins, here we compare the folding mechanisms of the two alternative spliced forms of a PDZ domain (PDZ2 and PDZ2as) that share a nearly identical sequence and structure, while displaying different frustration patterns. The analysis, based on the kinetic characterization of a large number of site‐directed mutants, reveals that although the late stages for folding are very robust and biased by native topology, the early stages are more malleable and dominated by local frustration. The results are briefly discussed in the context of the energy‐landscape theory.
Stabilisierung von anorganischem Acetylen, HBNH, mithilfe flankierender koordinativer Wechselwirkungen
Authors: Swarnakar Anindya K. , Hering‐Junghans Christian , Nagata Koichi , Ferguson Michael J. , McDonald Robert , Tokitoh Norihiro , Rivard Eric
Published: July 2015

Ein stabiler Donor‐Akzeptor‐Koordinationskomplex des schwer greifbaren Stamm‐Iminoborans HBNH (ein strukturelles Analog von Acetylen) wird beschrieben. Diese Spezies wurde durch eine thermisch induzierte N2‐Eliminierung/1,2‐H‐Migration generiert, ausgehend von einem Hydrido(azido)boran‐Addukt NHC⋅BH2N3 (NHC=N‐heterocyclisches Carben) in der Gegenwart eines fluorierten Triarylborans. Der Mechanismus dieses Prozesses wurde mithilfe von Berechnungen und Isotopenmarkierungsstudien untersucht. Diese Umwandlung stellt eine neue und potentiell modulare Route zu ungesättigten anorganischen Baueinheiten für fortgeschrittene Materialien dar.
Catalytic Synthesis of N‐Unprotected Piperazines, Morpholines, and Thiomorpholines from Aldehydes and SnAP Reagents
Authors: Luescher Michael U. , Bode Jeffrey W.
Published: July 2015

Commercially available SnAP (stannyl amine protocol) reagents allow the transformation of aldehydes and ketones into a variety of N‐unprotected heterocycles. By identifying new ligands and reaction conditions, a robust catalytic variant that expands the substrate scope to previously inaccessible heteroaromatic substrates and new substitution patterns was realized. It also establishes the basis for a catalytic enantioselective process through the use of chiral ligands.
Self‐Pillared, Single‐Unit‐Cell Sn‐MFI Zeolite Nanosheets and Their Use for Glucose and Lactose Isomerization
Authors: Ren Limin , Guo Qiang , Kumar Prashant , Orazov Marat , Xu Dandan , Alhassan Saeed M. , Mkhoyan K. Andre , Davis Mark E. , Tsapatsis Michael
Published: July 2015

Single‐unit‐cell Sn‐MFI, with the detectable Sn uniformly distributed and exclusively located at framework sites, is reported for the first time. The direct, single‐step, synthesis is based on repetitive branching caused by rotational intergrowths of single‐unit‐cell lamellae. The self‐pillared, meso‐ and microporous zeolite is an active and selective catalyst for sugar isomerization. High yields for the conversion of glucose into fructose and lactose to lactulose are demonstrated.
Pushing the Limits of Neutral Organic Electron Donors: A Tetra(iminophosphorano)‐Substituted Bispyridinylidene
Authors: Hanson Samuel S. , Doni Eswararao , Traboulsee Kyle T. , Coulthard Graeme , Murphy John A. , Dyker C. Adam
Published: July 2015

A new ground‐state organic electron donor has been prepared that features four strongly π‐donating iminophosphorano substituents on a bispyridinylidene skeleton. Cyclic voltammetry reveals a record redox potential of −1.70 V vs. saturated calomel electrode (SCE) for the couple involving the neutral organic donor and its dication. This highly reducing organic compound can be isolated (44 %) or more conveniently generated in situ by a deprotonation reaction involving its readily prepared pyridinium ion precursor. This donor is able to reduce a variety of aryl halides, and, owing to its redox potential, was found to be the first organic donor to be effective in the thermally induced reductive SN bond cleavage of N,N‐dialkylsulfonamides, and reductive hydrodecyanation of malonitriles.
Rechargeable Hydrogen Storage System Based on the Dehydrogenative Coupling of Ethylenediamine with Ethanol
Authors: Hu Peng , Ben‐David Yehoshoa , Milstein David
Published: July 2015

A novel and simple hydrogen storage system was developed, based on the dehydrogenative coupling of inexpensive ethylenediamine with ethanol to form diacetylethylenediamine. The system is rechargeable and utilizes the same ruthenium pincer catalyst for both hydrogen loading and unloading procedures. It is efficient and uses a low catalyst loading. Repetitive reversal reactions without addition of new catalyst result in excellent conversions in both the dehydrogenation and hydrogenation procedures in three cycles.
Protein‐Induced Color Shift of Carotenoids in β‐Crustacyanin
Authors: Gamiz‐Hernandez Ana P. , Angelova Iva Neycheva , Send Robert , Sundholm Dage , Kaila Ville R. I.
Published: July 2015

β‐Crustacyanin (β‐CR) is a pigment protein responsible for the blue color of lobsters. We show using correlated ab initio calculations how the protein environment tunes the chromophores of β‐CR through electrostatic and steric effects.
Semiconducting Polymer Nanoparticles with Persistent Near‐Infrared Luminescence for In Vivo Optical Imaging
Authors: Palner Mikael , Pu Kanyi , Shao Shirley , Rao Jianghong
Published: July 2015

Materials with persistent luminescence are attractive for in vivo optical imaging since they have a long lifetime that allows the separation of excitation of fluorophores and image acquisition for time‐delay imaging, thus eliminating tissue autofluorescence associated with fluorescence imaging. Persistently luminescent nanoparticles have previously been fabricated from toxic rare‐earth metals. This work reports that nanoparticles made of the conjugated polymer MEH‐PPV can generate luminescence persisting for an hour upon single excitation. A near‐infrared dye was encapsulated in the conjugated polymer nanoparticle to successfully generate persistent near‐infrared luminescence through resonance energy transfer. This new persistent luminescence nanoparticles have been demonstrated for optical imaging applications in living mice.
From Mesomorphic Phosphine Oxide to Clustomesogens Containing Molybdenum and Tungsten Octahedral Cluster Cores
Authors: Cîrcu Viorel , Molard Yann , Amela‐Cortes Maria , Bentaleb Ahmed , Barois Philippe , Dorcet Vincent , Cordier Stéphane
Published: July 2015

New clustomesogens (i.e., metal atom clusters containing liquid crystalline (LC) materials) have been obtained by grafting neutral cyanobiphenyl (CB)‐ or cholesteryl‐containing tailor‐made dendritic mesomorphic triphenylphosphine oxide ligands on luminescent (M6Cli8)4+ octahedral cluster cores (M=Mo, W). The LC properties were studied by a combination of polarizing optical microscopy (POM), differential scanning calorimetry (DSC), and X‐ray powder diffraction analyses. While the organic ligands showed various mesophase types ranging from nematic, SmA columnar (SmACol), SmA, and SmC phases, it turned out that the corresponding clustomesogens formed layered phases (SmA) over a wide range of temperatures that depend on the nature and density of mesogenic groups employed. Intrinsic luminescence properties of the cluster precursors are preserved over the entire range of LC phase existence.
Diphenyliodonium‐Catalyzed Fluorination of Arynes: Synthesis of ortho‐Fluoroiodoarenes
Authors: Zeng Yuwen , Li Guangyu , Hu Jinbo
Published: July 2015

Described is a one‐pot vicinal fluorination‐iodination of arynes at room temperature. The diphenyliodonium salt proved to be a privileged catalyst for this nucleophilic fluorination process using CsF as a fluorine source, and a subsequent facile electrophilic iodination with C4F9I was also found to be crucial to ensure the efficient fluorination. This new synthetic protocol has a broad substrate scope under mild reaction conditions.
Synthesis and Evaluation of GdIII‐Based Magnetic Resonance Contrast Agents for Molecular Imaging of Prostate‐Specific Membrane Antigen
Authors: Banerjee Sangeeta Ray , Ngen Ethel J. , Rotz Matthew W. , Kakkad Samata , Lisok Ala , Pracitto Richard , Pullambhatla Mrudula , Chen Zhengping , Shah Tariq , Artemov Dmitri , Meade Thomas J. , Bhujwalla Zaver M. , Pomper Martin G.
Published: July 2015

Magnetic resonance (MR) imaging is advantageous because it concurrently provides anatomic, functional, and molecular information. MR molecular imaging can combine the high spatial resolution of this established clinical modality with molecular profiling in vivo. However, as a result of the intrinsically low sensitivity of MR imaging, high local concentrations of biological targets are required to generate discernable MR contrast. We hypothesize that the prostate‐specific membrane antigen (PSMA), an attractive target for imaging and therapy of prostate cancer, could serve as a suitable biomarker for MR‐based molecular imaging. We have synthesized three new high‐affinity, low‐molecular‐weight GdIII‐based PSMA‐targeted contrast agents containing one to three GdIII chelates per molecule. We evaluated the relaxometric properties of these agents in solution, in prostate cancer cells, and in an in vivo experimental model to demonstrate the feasibility of PSMA‐based MR molecular imaging.
A Morphological Transition of Inverse Mesophases of a Branched‐Linear Block Copolymer Guided by Using Cosolvents
Authors: La Yunju , An Tae Hyun , Shin Tae Joo , Park Chiyoung , Kim Kyoung Taek
Published: July 2015

We report here a strategy for influencing the phase and lattice of the inverse mesophases of a single branched‐linear block copolymer (BCP) in solution which does not require changing the structure of the BCP. The phase of the self‐assembled structures of the block copolymer can be controlled ranging from bilayer structures of positive curvature (polymersomes) to inverse mesophases (triply periodic minimal surfaces and inverse hexagonal structures) by adjusting the solvent used for self‐assembly. By using solvent mixtures to dissolve the block copolymer we were able to systematically change the affinity of the solvent toward the polystyrene block, which resulted in the formation of inverse mesophases with the desired lattice by self‐assembly of a single branched‐linear block copolymer. Our method was also applied to a new solution self‐assembly method for a branched‐linear block copolymer on a stationary substrate under humidity, which resulted in the formation of large mesoporous films. Our results constitute the first controlled transition of the inverse mesophases of block copolymers by adjusting the solvent composition.
A Versatile Approach Towards Nucleobase‐Modified Aptamers
Authors: Tolle Fabian , Brändle Gerhard M. , Matzner Daniel , Mayer Günter
Published: July 2015

A novel and versatile method has been developed for modular expansion of the chemical space of nucleic acid libraries, thus enabling the generation of nucleobase‐modified aptamers with unprecedented recognition properties. Reintroduction of the modification after enzymatic replication gives broad access to many chemical modifications. This wide applicability, which is not limited to a single modification, will rapidly advance the application of in vitro selection approaches beyond what is currently feasible and enable the generation of aptamers to many targets that have so far not been addressable.
Self‐Assembled Nanocomposite Organic Polymers with Aluminum and Scandium as Heterogeneous Water‐Compatible Lewis Acid Catalysts
Authors: Miyamura Hiroyuki , Sonoyama Arisa , Hayrapetyan Davit , Kobayashi Shū
Published: July 2015

While water‐compatible Lewis acids have great potential as accessible and environmentally benign catalysts for various organic transformations, efficient immobilization of such Lewis acids while keeping high activity and without leaching of metals even under aqueous conditions is a challenging task. Self‐assembled nanocomposite catalysts of organic polymers, carbon black, aluminum reductants, and scandium salts as heterogeneous water‐compatible Lewis acid catalysts are described. These catalysts could be successfully applied to various CC bond‐forming reactions without leaching of metals. Scanning transmission electron microscopy analyses revealed that the nanocomposite structure of Al and Sc was fabricated in these heterogeneous catalysts. It is noted that Al species, which are usually decomposed rapidly in the presence of water, are stabilized under aqueous conditions.
Fine Tuning of β‐Peptide Foldamers: a Single Atom Replacement Holds Back the Switch from an 8‐Helix to a 12‐Helix
Authors: Altmayer‐Henzien Amandine , Declerck Valérie , Farjon Jonathan , Merlet Denis , Guillot Régis , Aitken David J.
Published: July 2015

Cyclic homologated amino acids are important building blocks for the construction of helical foldamers. N‐aminoazetidine‐2‐carboxylic acid (AAzC), an aza analogue of trans‐2‐aminocyclobutanecarboxylic acid (tACBC), displays a strong hydrazino turn conformational feature, which is proposed to act as an 8‐helix primer. tACBC oligomers bearing a single N‐terminal AAzC residue were studied to evaluate the ability of AAzC to induce and support an 8‐helix along the oligopeptide length. While tACBC homooligomers assume a dominant 12‐helix conformation, the aza‐primed oligomers preferentially adopt a stabilized 8‐helix conformation for an oligomer length up to 6 residues. The (formal) single‐atom exchange at the N terminus of a tACBC oligomer thus contributes to the sustainability of the 8‐helix, which resists the switch to a 12‐helix. This effect illustrates atomic‐level programmable design for fine tuning of peptide foldamer architectures.
Synergistic Effect between Metal–Nitrogen–Carbon Sheets and NiO Nanoparticles for Enhanced Electrochemical Water‐Oxidation Performance
Authors: Wang Jun , Li Kai , Zhong Hai‐xia , Xu Dan , Wang Zhong‐li , Jiang Zheng , Wu Zhi‐jian , Zhang Xin‐bo
Published: July 2015

Identifying effective means to improve the electrochemical performance of oxygen‐evolution catalysts represents a significant challenge in several emerging renewable energy technologies. Herein, we consider metal–nitrogen–carbon sheets which are commonly used for catalyzing the oxygen‐reduction reaction (ORR), as the support to load NiO nanoparticles for the oxygen‐evolution reaction (OER). FeNC sheets, as the advanced supports, synergistically promote the NiO nanocatalysts to exhibit superior performance in alkaline media, which is confirmed by experimental observations and density functional theory (DFT) calculations. Our findings show the advantages in considering the support effect for designing highly active, durable, and cost‐effective OER electrocatalysts.
Specific Photochemical Dehydrocoupling of N‐Heterocyclic Phosphanes and Their Use in the Photocatalytic Generation of Dihydrogen
Authors: Puntigam Oliver , Könczöl László , Nyulászi László , Gudat Dietrich
Published: July 2015

N‐Heterocyclic phosphanes react under UV irradiation in a highly selective dehydrocoupling reaction to diphosphanes and H2. Computational studies suggest that the product formation is initiated by the formation of dimeric molecular associates whose electronic excitation yields H2 and a diphosphane. Combining the dehydrocoupling of sterically demanding phosphanes with Mg‐reduction of the formed diphosphanes allows constructing a reaction cycle for the photocatalytic reductive generation of H2 from Et3NH+.
RhIII‐Catalyzed CH Activation with Pyridotriazoles: Direct Access to Fluorophores for Metal‐Ion Detection
Authors: Kim Ju Hyun , Gensch Tobias , Zhao Dongbing , Stegemann Linda , Strassert Cristian A. , Glorius Frank
Published: July 2015

The first CH bond activation with pyridotriazoles as coupling partners is presented using a RhIII catalyst. The pyridotriazoles can be used as new carbene precursors in CH activation for direct access to novel fluorescent scaffolds. These tunable fluorophores can be applied for the detection of metal ions.
Enantioselective Total Synthesis of (−)‐Hosieine A
Authors: Ouyang Jie , Yan Rui , Mi Xianwei , Hong Ran
Published: July 2015

The first total synthesis of (−)‐hosieine A was accomplished and features an unprecedented nitroso–ene cyclization to construct the 2‐azabicyclo[3.2.1]octane ring system. Phosphine‐enabled stereoselective bromohydrination provided interesting mechanistic insights into the anti‐Markovnikov process. Also noteworthy is the retention of stereochemistry at C9 in the facile radical debromination initiated by Et3B/air.
Nickel‐Catalyzed Cyclopropanation with NMe4OTf and nBuLi
Authors: Künzi Stefan A. , Sarria Toro Juan Manuel , den Hartog Tim , Chen Peter
Published: July 2015

Nickel was identified as a catalyst for the cyclopropanation of unactivated olefins by using in situ generated lithiomethyl trimethylammonium triflate as a methylene donor. A mechanistic hypothesis is proposed in which the generation of a reactive nickel carbene explains several interesting observations. Additionally, our findings shed light on a report by Franzen and Wittig published in 1960 that had been retracted later owing to irreproducibility, and provide a rational basis for the systematic development of the reaction for preparative purposes as an alternative to diazomethane or Simmons–Smith conditions.
Foaming behavior of bio‐based blends based on thermoplastic gelatin and poly(butylene succinate)
Authors: Oliviero Maria , Sorrentino Luigi , Cafiero Livia , Galzerano Barbara , Sorrentino Andrea , Iannace Salvatore
Published: July 2015

Biodegradable thermoplastic gelatin/poly(butylene succinate) (TPG/PBS) foams were prepared by melt mixing and subsequent batch foaming with supercritical CO2. Shear viscosity and calorimetric properties of the various blends were investigated using a rotational rheometer and a differential scanning calorimeter, respectively. TPG/PBS blends show poor miscibility at all blend ratios. The addition of PBS reduced the melt viscosity and increased both the CO2 diffusivity and the thermal stability of TPG. Results from foaming experiments show that the blend foams exhibit smaller cell size and higher cell density compared to the neat TPG foam due to the lower melt viscosity and to their lower gas barrier. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42704.
Effects of pore morphology and size on antimicrobial activity of chitosan/poly(ethylene glycol) diacrylate macromer semi‐IPNhydrogels
Authors: Bedel Nazlı Sokmen , Tezcan Melek , Ceylan Ozgur , Gurdag Gulten , Cicek Huseyin
Published: July 2015

The objective of this study was to obtain antibacterial active chitosan/poly(ethylene glycol) diacrylate macromere (CS/PEGM) semi‐IPN hydrogels near a neutral pH level by changing their pore size and morphology. These hydrogels were prepared from CS and PEGM with different molecular weights in the presence of pore‐forming agents, poly (ethylene glycol) (PEG) or sodium bicarbonate (NaHCO3), by using two different initiator system, namely chemical or UV. A combination of CS with PEG or NaHCO3in the presence of PEGM could be able to create desired pore formation in both initiator systems. The antibacterial activity of hydrogels changed with the molecular weight (g/mol) of PEGM in the order 2000>400>8000. A chemical initiation system was found more suitable than the UV initiation system for antibacterial activity. Hydrogels showing the highest antibacterial activity onStaphylococcus aureusandEscherichia colihave medium or distributed pore size and interconnected pores. Hydrogels prepared with PEGM (Mn: 2000 g/mol) were proposed for antibacterial wound dressing and soft tissue regeneration applications owing to their antibacterial activity and elastic modulus. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2015,132, 42707.
Synthesis and Evaluation of a Series of Oleanolic Acid Saponins as α‐Glucosidase and α‐Amylase Inhibitors
Authors: Guo Tiantian , Wu Shaoping , Guo Sen , Bai Lu , Liu Qingchao , Bai Naisheng
Published: July 2015

Sixteen naturally occurring oleanolic acid saponins and their derivatives were synthesized in an efficient and practical strategy, and their inhibitory activities against α‐glucosidase and α‐amylase were evaluated in vitro. Among all the compounds, 28‐O‐monoglucoside 8 exhibited remarkably potent inhibitory activity against α‐glucosidase with an IC50 value of 87.3 µM, which was fivefold stronger than that of the antidiabetic acarbose. Based on the preliminary structure–activity relationships, for 28‐O‐monoglucosides, the presence of a terminal α‐l‐rhamnopyranosyl residue enhanced the α‐glucosidase and α‐amylase inhibitory activities. Furthermore, for 3,28‐O‐bidesmosides, sugar‐substituted moieties attached to the C‐3 and C‐28 positions of the oleanolic acid scaffold are helpful to increase the inhibitory activities against α‐amylase and α‐glucosidase.