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Ewa Erdmann, Marta Łabuda, Nestor Fabián Aguirre, Sergio Díaz-Tendero, Manuel Alcami
We present a complete exploration of the different fragmentation mechanisms of furan (C4H4O) operating at low and high energies. Three different theoretical approaches are combined to determine the structure of all possible reaction intermediates, many of them not described in previous studies, and a large number of pathways involving three types of fundamental elementary mechanisms: isomerization, fragmentation and H/H2 loss processes, this last one was not yet explored. Our results are compared with the existing experimental and theoretical investigations for furan fragmentation...
March 15, 2018: Journal of Physical Chemistry. A
David B Medeiros, Leonardo Perez de Souza, Werner C Antunes, Wagner L Araújo, Danilo M Daloso, Alisdair R Fernie
Sucrose has long been thought to play an osmolytic role in stomatal opening. However, recent evidence supports the idea that the role of sucrose in this process is primarily energetic. Here we used a combination of stomatal aperture assays coupled with kinetic [U-13 C]-sucrose isotope labelling experiments to confirm that sucrose is degraded during light-induced stomatal opening and to define the fate of the C released from sucrose breakdown. We additionally show that addition of sucrose in the medium did not enhance light-induced stomatal opening...
March 15, 2018: Plant Journal: for Cell and Molecular Biology
Evgeny J Chumin, Joaquín Goñi, Meredith E Halcomb, Timothy C Durazzo, Mario Džemidžić, Karmen K Yoder
BACKGROUND: Diffusion weighted imaging (DWI) has been widely used to investigate the integrity of white matter (WM; indexed by fractional anisotropy, FA) in alcohol dependence and cigarette smoking. These disorders are highly comorbid, yet cigarette use has often not been adequately controlled in neuroimaging studies of alcohol dependent populations. In addition, information on white matter deficits in currently drinking, nontreatment-seeking (NTS) individuals with alcohol dependence is limited...
March 15, 2018: Alcoholism, Clinical and Experimental Research
Yasuo Hagihara, Takashi Nara
OBJECTIVES: This study aimed to investigate differences in the diaphyseal cross-sectional geometry (CSG) of the metatarsal bones (MTs) between two populations with different habitual activities: the Jomon hunter-gatherers and modern Japanese people. MATERIALS AND METHODS: We evaluated the first through fifth MTs of 117 skeleton samples: 59 (33 men and 26 women) were obtained from Late and Final Jomon period archeological sites and 58 (31 men and 27 women) were from modern Japanese people...
March 15, 2018: American Journal of Physical Anthropology
Longchao Yao, Jun Chen, Paul E Sojka, Xuecheng Wu, Kefa Cen
Dynamic stringy objects such as liquid rims and ligaments are frequently observed in important applications such as the multiphase breakup of fuel droplets. We develop a new method based on digital in-line holography to automatically measure complicated stringy objects. A static spring mounted on a rotator is measured to validate the effectiveness and accuracy of the method. The sections are extracted along the skeleton of the spring in a depth-of-field extended image and then sized and located as individual particles using a hybrid method...
March 15, 2018: Optics Letters
Stefan Flohr
About 100 hominin bones were found during excavations at the Liang Bua cave on the island of Flores, Indonesia. More than 60 of them were assigned to the partial skeleton LB1 which was designated as the holotype of a new species, Homo floresiensis . Analyses of skeletal proportions of LB1 led to the conclusion that its foot was exceptionally long relative to femur and tibia, respectively. This ratio was considered a unique feature that contributes to the definition of the new species. The published illustrations of the in situ -situation and the published inventory of the bones suggest a high degree of commingling rather than the presence of larger anatomically joining units that was asserted in the publications on the findings...
March 14, 2018: Anthropologischer Anzeiger; Bericht über die Biologisch-anthropologische Literatur
Jie-Li Lv, Zhou Li, Li-Min Guo, Lai-Bin Zhang
Two new sesquiterpene lactones, artelavanolides A (1) and B (2), and four known sesquiterpene lactones (3-6) were isolated from the leaves of Artemisia lavandulaefolia. Their structures were elucidated based on the analysis of spectroscopic data (1D, 2D NMR and HRESIMS). The absolute configuration of 1 was determined by the analysis of single-crystal X-ray diffraction data. Artelavanolide A (1) is a rare sesquiterpene lactone possessing an unusual skeleton with the linkage of Me(14)-C(1) that is probably formed through a rearrangement of the guaiane-type sesquiterpenoids...
March 15, 2018: Chemistry & Biodiversity
G F Funston, S E Mendonca, P J Currie, R Barsbold
Dinosaur community composition data for eleven fossil localities in the Late Cretaceous Nemegt Basin of Mongolia are compiled from field observations and records in the literature. Counts were generated from skeletons and represent numbers of individuals preserved in each locality. These data were used in the analyses of Funston et al. [1] "Oviraptorosaur anatomy, diversity, and ecology in the Nemegt Basin" in the Nemegt Ecosystems Special Issue of Palaeogeography, Palaeoclimatology, Palaeoecology, where the results are discussed...
February 2018: Data in Brief
Glen M Blake, Tanuj Puri, Musib Siddique, Michelle L Frost, Amelia E B Moore, Ignac Fogelman
Dynamic positron emission tomography (PET) imaging with fluorine-18 labelled sodium fluoride ([18 F]NaF) allows the quantitative assessment of regional bone formation by measuring the plasma clearance of fluoride to bone at any site in the skeleton. Today, hybrid PET and computed tomography (CT) dual-modality systems (PET/CT) are widely available, and [18 F]NaF PET/CT offers a convenient non-invasive method of studying bone formation at the important osteoporotic fracture sites at the hip and spine, as well as sites of pure cortical or trabecular bone...
February 2018: Quantitative Imaging in Medicine and Surgery
Rebecca Albright, Yuichiro Takeshita, David A Koweek, Aaron Ninokawa, Kennedy Wolfe, Tanya Rivlin, Yana Nebuchina, Jordan Young, Ken Caldeira
Coral reefs feed millions of people worldwide, provide coastal protection and generate billions of dollars annually in tourism revenue. The underlying architecture of a reef is a biogenic carbonate structure that accretes over many years of active biomineralization by calcifying organisms, including corals and algae. Ocean acidification poses a chronic threat to coral reefs by reducing the saturation state of the aragonite mineral of which coral skeletons are primarily composed, and lowering the concentration of carbonate ions required to maintain the carbonate reef...
March 14, 2018: Nature
Qingqing Pan, Yaping Luo, Xinxin Cao, Yanru Ma, Fang Li
A 60-year-old woman diagnosed with multiple myeloma was referred for Ga-pentixafor PET/CT for evaluation of the disease. Diffuse and intense radioactivity throughout the axial and proximal appendicular skeleton was noted on PET/CT images, suggestive of extensive involvement of multiple myeloma.
March 13, 2018: Clinical Nuclear Medicine
Thierry Baussant, Marianne Nilsen, Elisa Ravagnan, Stig Westerlund, Sreerekha Ramanand
This study aimed at providing confidence in the predictability of the impacts of drill cuttings (DC) discharge on the cold-water coral Lophelia pertusa. L. pertusa was exposed to DC from offshore exploration in the lab with the goal to assess precautionary thresholds of effects. Two exposure scenarios with DC were tested: a long-term (LT) pulsed exposure (12 weeks, peak concentrations: 2-50 mg/L, mean concentrations: 1-25 mg/L) and a short-term (ST) continuous exposure (2.5 weeks, mean concentrations: 4-42 mg/L)...
March 14, 2018: Journal of Toxicology and Environmental Health. Part A
Yasuaki Kawaguchi, Asami Nagata, Kei Kurokawa, Haruna Yokosawa, Chisato Mukai
Treatment of dodecatrienyne derivatives with [RhCl(CO)2]2 in refluxing toluene effected the cycloisomerization to produce tricyclo[,6]dodecadienes. The one-carbon shortened undecatrienyne derivatives, however, afforded bicyclo[6.3.0]undecatriene derivatives instead of tricyclic compounds, the latter of which are well known as a basic skeleton of naturally occurring octanoids. On the basis of two experiments with deuterated substrates, a plausible reaction mechanism for the construction of these products was proposed...
March 14, 2018: Chemistry: a European Journal
O B Afanassieva
Based on recently obtained original and published data on the fine structure of the external skeleton of osteostracan agnathans (Osteostraci, Agnatha), possible modes of the formation of their hard cover in the course of the horizontal growth of the exoskeleton are characterized. The developmental models for the formation of various configurations of cephalothoracic shields typical for osteostracans are revealed. It is shown that, in the morphogenesis of the hard cover of this group of early vertebrates, a significant part of the variants of the exoskeleton horizontal growth characteristic of early vertebrates are observed...
January 2018: Doklady Biological Sciences: Proceedings of the Academy of Sciences of the USSR, Biological Sciences Sections
Yuji Hayashino, Masatake Sugita, Hidetoshi Arima, Tetsumi Irie, Takeshi Kikuchi, Fumio Hirata
It has been found that a cyclodextrin derivative, 2-hydroxypropyl-β-cyclodextrin (HPβCD), has reasonable therapeutic effect on Niemann-Pick disease type C which is caused by abnormal accumulation of unesterified cholesterol and glycolipids in the lysosomes and shortage of esterified cholesterol in other cellular compartments. We study the binding affinity and mode of HPβCD with cholesterol in order to elucidate the possible mechanism of HPβCD for removing cholesterol from the lysosomes. The dominant binding mode of HPβCD with cholesterol is found based on the Molecular Dynamics (MD) simulation and a statistical mechanics theory of liquids, or the 3D reference interaction site model theory with Kovalenko-Hirata closure relation (3D-RISM-KH)...
March 13, 2018: Journal of Physical Chemistry. B
Yanjun Wan, Xuchun Zheng, Cheng Ma
A novel strategy to generate functionalized 1-azatriene intermediates for 6π electrocyclizations was developed by using readily accessible dienyne-imides and various terminal olefins under Pd(II) catalysis. Taking advantage of the sequential cooperation between preloaded and incorporated functional handles at 1,3-dien-5-yne skeletons, this protocol not only enables the selective generation of putative 1-azatrienes but significantly accelerates their thermal 6π-electrocyclic ring closure processes to a series of highly substituted furo[2,3-b]dihydropyridine derivatives in good yields...
March 13, 2018: Angewandte Chemie
Riku Takahashi, Tao Lin Sun, Yoshiyuki Saruwatari, Takayuki Kurokawa, Daniel R King, Jian Ping Gong
Reinforcing hydrogels with a rigid scaffold is a promising method to greatly expand the mechanical and physical properties of hydrogels. One of the challenges of creating hydrogel composites is the significant stress that occurs due to swelling mismatch between the water-swollen hydrogel matrix and the rigid skeleton in aqueous media. This stress can cause physical deformation (wrinkling, buckling, or fracture), preventing the fabrication of robust composites. Here, a simple yet versatile method is introduced to create "macroscale" hydrogel composites, by utilizing a rigid reinforcing phase that can relieve stress-induced deformation...
March 13, 2018: Advanced Materials
Han Gao, Gang Li, Hong-Xiang Lou
Exploration of structurally novel natural products greatly facilitates the discovery of biologically active pharmacophores that are biologically validated starting points for the development of new drugs. Endophytes that colonize the internal tissues of plant species, have been proven to produce a large number of structurally diverse secondary metabolites. These molecules exhibit remarkable biological activities, including antimicrobial, anticancer, anti-inflammatory and antiviral properties, to name but a few...
March 13, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Qian Zhao, Qizhen Zhu, Jiawei Miao, Zhaoruxin Guan, Huan Liu, Renjie Chen, Yabin An, Feng Wu, Bin Xu
With the high energy density of 2600 Wh kg-1, lithium-sulfur (Li-S) batteries have been considered as one of the most promising energy storage systems. However, the serious capacity fading resulting from shuttle effect hinders its commercial application. Encapsulating small S2-4 molecules into the pores of ultra-microporous carbon (UMC) can eliminate the dissolved polysulfudes, thus completely inhibit the shuttle effect. Nevertheless, the sulfur loading of S2-4/UMC is usually not higher than 1 mg cm-2 due to the limited pore volume of UMC, which is a great challenge for small sulfur cathode...
March 13, 2018: ACS Applied Materials & Interfaces
Ivan Andreevich Yaremenko, Gabriel Dos Passos Gomes, Peter Sergeevich Radulov, Yulia Yur'evna Belyakova, Anatoliy Evgen'evich Vilikotskiy, Vera Andreevna Vil', Alexander A Korlyukov, Gennady Ivanovich Nikishin, Igor V Alabugin, Alexander Olegovich Terent'ev
Reactions of 1,5-diketones with H2O2 open an ozone-free approach to ozonides. Bridged ozonides are formed readily at the room temperature in the presence of strong Brønsted or Lewis acids such as H2SO4, p-TsOH, HBF4, or BF3•Et2O. The expected bridged tetraoxanes, the products of double H2O2 addition, were not detected. This procedure is readily scalable to produce gram quantities of the ozonides. Bridged ozonides are stable and can be useful as building block for bioconjugation and further synthetic transformations...
March 13, 2018: Journal of Organic Chemistry
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