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Asha Brown, Thomas Lang, Kathleen M Mullen, Paul D Beer
An active metal template strategy was used to synthesise a neutral indolocarbazole containing [2]rotaxane anion host system. (1)H NMR anion binding investigations reveal that the [2]rotaxane recognises a range of monoanions in acetone-d5 : D2O 95 : 5 with an unusual interlocked host selectivity for acetate and dihydrogenphosphate oxoanions over halides. The rotaxane displays an overall selectivity for the sulfate dianion, favouring a 2 : 1 host : guest binding stoichiometry at low sulfate concentration and a 1 : 1 stoichiometry in the presence of excess sulfate...
May 22, 2017: Organic & Biomolecular Chemistry
Tia Jarvis, Carleton G Collins, Janel M Dempsey, Allen G Oliver, Bradley D Smith
Squaraine rotaxanes are mechanically interlocked molecules comprised of a dumbbell shaped squaraine dye inside a tetralactam macrocycle. Previous squaraine rotaxanes have employed planar squaraine dyes with 4-aminophenyl, 2-aminothiophene or N-amino units appended to the central C4O2 core. Here we describe two rotaxanes that encapsulate a 3,3-dimethylindoline squaraine inside a tetralactam with anthracene sidewalls. The rotaxanes were prepared by a templated clipping reaction and an X-ray crystal structure shows that the squaraine gem-dimethyl groups force a relatively wide separation between the macrocycle anthracene sidewalls...
May 18, 2017: Journal of Organic Chemistry
Asifa Siraj
This study explores the complex interaction between ethnicity, gender and [homo]sexuality and how this creates a framework of stigma that compels some British Pakistani lesbians to remain within the closet. The 'closet' here is a metaphor that describes the concealment of one's homosexual identity and the outward 'performance' of heterosexuality. British Pakistani lesbians precariously inhabit a sociocultural environment that constrains the expression of female sexuality. Women who oppose and contravene heteronormative values and ideals unsettle comfortable assumptions of heterosexuality...
May 16, 2017: Culture, Health & Sexuality
Xiaoyu Wu, Urko Petralanda, Lu Zheng, Yuan Ren, Rongwei Hu, Sang-Wook Cheong, Sergey Artyukhin, Keji Lai
Domain walls (DWs) in ferroic materials, across which the order parameter abruptly changes its orientation, can host emergent properties that are absent in the bulk domains. Using a broadband (10(6) to 10(10) Hz) scanning impedance microscope, we show that the electrical response of the interlocked antiphase boundaries and ferroelectric DWs in hexagonal rare-earth manganites (h-RMnO3) is dominated by the bound-charge oscillation rather than free-carrier conduction at the DWs. As a measure of the rate of energy dissipation, the effective conductivity of DWs on the (001) surfaces of h-RMnO3 at gigahertz frequencies is drastically higher than that at dc, whereas the effect is absent on surfaces with in-plane polarized domains...
May 2017: Science Advances
Alexander Yulaev, Alexey Lipatov, Annie Xi Lu, Alexander Sinitskii, Marina S Leite, Andrei Kolmakov
We demonstrate a technique for facile encapsulation and adhesion of micro- and nano objects on arbitrary substrates, stencils, and micro structured surfaces by ultrathin graphene oxide membranes via a simple drop casting of graphene oxide solution. A self-assembled encapsulating membrane forms during the drying process at the liquid-air and liquid-solid interfaces and consists of a water-permeable quasi-2D network of overlapping graphene oxide flakes. Upon drying and interlocking between the flakes, the encapsulating coating around the object becomes mechanically robust, chemically protective, and yet highly transparent to electrons and photons in a wide energy range, enabling microscopic and spectroscopic access to encapsulated objects...
January 23, 2017: Advanced Functional Materials
Julián Valero, Finn Lohmann, Michael Famulok
Interlocked molecular architectures are well known in supramolecular chemistry and are widely used for various applications like sensors, molecular machines and logic gates. The use of DNA for constructing these interlocked structures has increased significantly within the current decade. Because of Watson-Crick base pairing rules, DNA is an excellent material for the self-assembly of well-defined interlocked nanoarchitectures. These DNA nanostructures exhibit sufficient stability, good solubility in aqueous media, biocompatibility, and can be easily combined with other biomolecules in bio-hybrid nano-assemblies...
May 12, 2017: Current Opinion in Biotechnology
Cheng Yuan, Mingsong Chen, Jing Luo, Xiaona Li, Qiang Gao, Jianzhang Li
In this study, an eco-friendly soy protein adhesive was developed that utilized two components from soybean meal without addition of any toxic material. A plant-based, water-soluble and inexpensive soybean soluble polysaccharide was used as the novel renewable material to combine with soy protein to produce a soy protein adhesive. Three-plywood was fabricated with the resulting adhesive, and its wet shear strength was measured. The results showed the wet shear strength of plywood bonded by the adhesive reached 0...
August 1, 2017: Carbohydrate Polymers
David Anthony Morrison, Alan Matthew Kop, Anastasia Nilasaroya, Marian Sturm, Kathryn Shaw, Stephen Honeybul
Cranioplasty is necessary for patients that have undergone craniectomy following trauma, stroke or other causes of elevated intracranial pressure. This study assessed the effectiveness of treating cranial defects with a combination of allogeneic mesenchymal stromal cells (MSC) on a ceramic carrier and polymer scaffold, to produce viable bone and healing of a cranial void. Patients underwent a baseline CT scan for construct design. Two sets of interlocking moulds were 3D-printed to enable shaping of two polymer meshes which formed the boundaries of the construct corresponding to restoration of the skull interna and externa...
May 9, 2017: Journal of Tissue Engineering and Regenerative Medicine
Jiang-Shan Li, Jingzi Beiyuan, Daniel C W Tsang, Lei Wang, Chi Sun Poon, Xiang-Dong Li, Scott Fendorf
Geogenic sources of arsenic (As) have aroused extensive environmental concerns in many countries. This study evaluated the vertical profiles, leaching characteristics, and surface characteristics of As-containing soils in Hong Kong. The results indicated that elevated levels of As (486-1985 mg kg(-1)) were mostly encountered in deeper layer (15-20 m below ground). Despite high concentrations, geogenic As displayed a high degree of chemical stability in the natural geochemical conditions, and there was minimal leaching of As in various leaching tests representing leachability, mobility, phytoavailability, and bioaccessibility...
May 6, 2017: Chemosphere
Yixin Bai, Rui Zhou, Jianyun Cao, Daqing Wei, Qing Du, Baoqiang Li, Yaming Wang, Dechang Jia, Yu Zhou
The sub-microporous microarc oxidation (MAO) coating covered Ti implant with micro-scale gouges has been fabricated via a multi-step MAO process to overcome the compromised bone-implant integration. The as-prepared implant has been further mediated by post-heat treatment to compare the effects of -OH functional group and the nano-scale orange peel-like morphology on osseointegration. The bone regeneration, bone-implant contact interface, and biomechanical push-out force of the modified Ti implant have been discussed thoroughly in this work...
July 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
Yan Wang, Wu Dai
Mouthpart structure and feeding behavior in the temperate firebug, Pyrrhocoris sibiricus Kuschakevich, an important pest that feeds on seeds of leguminous and gramineous plants, are described for the first time. Mouthparts were observed using scanning electron microscopy to examine the external morphology, distribution and abundance of sensilla on mouthparts. Feeding performance by adults on both seeds and shoots were observed using a binocular microscope. The four-segmented labium contains 3 types of sensilla trichodea, 3 types of sensilla basiconica, 1 type of sensilla placodea and 1 type of sensilla campaniformia...
2017: PloS One
Sarah E Boston, Arathi Vinayak, Xiaomin Lu, Susan Larue, Nicholas J Bacon, Jason A Bleedorn, Carlos H M Souza, Nicole P Ehrhart
OBJECTIVE: To document the outcome of dogs with appendicular primary bone tumors treated with stereotactic radiotherapy (SRT) and concurrent stabilization. STUDY DESIGN: Multi-institutional retrospective case series. ANIMALS: Eighteen dogs with presumptive or definitive diagnosis of appendicular osteosarcoma. METHODS: Medical records of dogs with appendicular primary bone tumors treated with SRT and stabilization were reviewed for signalment, preoperative staging and diagnostics, radiation dose, stabilization method, and outcome...
May 6, 2017: Veterinary Surgery: VS
Ryo Sekiya, Morihiko Fukuda, Reiko Kuroda
Interlocked dimer 2, which is composed of two physically interlocked monomers 1, has three cavities (cavity A × 2 and cavity B × 1) and can encapsulate three anions, such as NO3(-) and BF4(-), one anion per cavity. There are six possible encapsulation patterns, A-F; two (A and F) contain only one kind of anion and the others (B-E) contain both NO3(-) and BF4(-) at the same time with different ratios and with different positions. Anion competition experiments showed that in addition to F, which encapsulates three NO3(-) ions, C, in which NO3(-) and BF4(-) ions are captured in cavities A and cavity B, respectively, was selectively formed...
May 4, 2017: Organic & Biomolecular Chemistry
Joon-Yung Cha, Laila Khaleda, Hee Jin Park, Woe-Yeon Kim
Circadian clock is an internal system synchronized by external stimuli such as light and temperature and influences various physiological and developmental processes in living organisms. In Arabidopsis as a model plant, transcriptional, translational and post-translational processes are interlocked as by feedback loops between morning- and evening-phased genes. In a post-translational loop, plant-specific single-gene encoded GIGANTEA (GI) stabilize the F-box protein ZEITLUPE (ZTL) leading targeted-proteasomal degradation of TIMING OF CAB EXPRESSION 1 (TOC1) and PSEUDO-RESPONSE REGULATOR 5 (PRR5)...
April 24, 2017: BMB Reports
Jacklyn R Goodheart, Mark A Miller, Megan E Oest, Kenneth A Mann
With in vivo service there is loss of mechanical interlock between trabeculae and PMMA cement in total knee replacements. The mechanisms responsible for the loss of interlock are not known, but loss of interlock results in weaker cement-bone interfaces. The goal of this study was to determine the pattern of resorption of interdigitated bone using a series of 20 postmortem retrieved knee replacements with a wide range of time in service (3 to 22 years). MicroCT scans were obtained of a segment of the cement-bone interface below the tibial tray for each implant...
April 27, 2017: Journal of Orthopaedic Research: Official Publication of the Orthopaedic Research Society
Tian-Guang Zhan, Lin Wu, Zhixiong Zhao, Zhi-Bei Zhou, Meng-Yan Yun, Jie Wei, Si-Tai Zheng, Huan-Huan Yin, Kang-Da Zhang
Linear tetrathiafulvalene (TTF) oligomers were synthesized, which could not only form a pleated TTF˙(+) radical cation foldamer under oxidation conditions, but also interlocked with CBPQT(4+) to form folded donor-acceptor [3]pseudorotaxane in the neutral state of TTF. Moreover, switchable transformation between these two folded supramolecular structures was achieved under the alternative regulation of the redox states of TTF units.
May 11, 2017: Chemical Communications: Chem Comm
Xiaowei Li, Xiangyang Yuan, Pengchi Deng, Lixi Chen, Yi Ren, Chengyuan Wang, Lixin Wu, Wen Feng, Bing Gong, Lihua Yuan
Examples of using two-dimensional shape-persistent macrocycles, i.e. those having noncollapsible and geometrically well-defined skeletons, for constructing mechanically interlocked molecules are scarce, which contrasts the many applications of these macrocycles in molecular recognition and functional self-assembly. Herein, we report the crucial role played by macrocyclic shape-persistency in enhancing multipoint recognition for the highly efficient template-directed synthesis of rotaxanes. Cyclo[6]aramides, with a near-planar conformation, are found to act as powerful hosts that bind bipyridinium salts with high affinities...
March 1, 2017: Chemical Science
Sofía Leret, Yann Pouillon, Santiago Casado, Cristina Navío, Ángel Rubio, Emilio M Pérez
Many applications of carbon nanotubes require their chemical functionalization. Both covalent and supramolecular approaches have been extensively investigated. A less trodden path is the combination of both covalent and noncovalent chemistries, where the formation of covalent bonds triggers a particularly stable noncovalent interaction with the nanotubes. We describe a series of naphthalene diimide (NDI) bisalkene molecules that, upon mixing with single-walled carbon nanotubes (SWNTs) and Grubbs' catalyst, undergo two different reaction pathways...
March 1, 2017: Chemical Science
Ingra Mannhardt, Umber Saleem, Anika Benzin, Thomas Schulze, Birgit Klampe, Thomas Eschenhagen, Arne Hansen
Cardiac tissue engineering describes techniques to constitute three dimensional force-generating engineered tissues. For the implementation of these procedures in basic research and preclinical drug development, it is important to develop protocols for automated generation and analysis under standardized conditions. Here, we present a technique to generate engineered heart tissue (EHT) from cardiomyocytes of different species (rat, mouse, human). The technique relies on the assembly of a fibrin-gel containing dissociated cardiomyocytes between elastic polydimethylsiloxane (PDMS) posts in a 24-well format...
April 15, 2017: Journal of Visualized Experiments: JoVE
James E M Lewis, Paul D Beer, Stephen J Loeb, Stephen M Goldup
The use of metal ions to template the synthesis of catenanes by Sauvage and co-workers was a pivotal moment in the development of the field of interlocked molecules. In this Review Article we shall examine the different roles metal-ligand interactions play in modern syntheses of interlocked molecules and materials, with a particular focus on seminal contributions and the advantages and disadvantages of employing metal ligand interactions.
May 9, 2017: Chemical Society Reviews
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