ubs Bulky 2,6-disubstituted aryl siloxanes and a disilanamine By scripts.iucr.org Published On :: 2020-02-06 The crystal structures of 5-bromo-1,3-di-tert-butyl-2-[(trimethylsilyl)oxy]benzene, C17H29BrOSi, (I), 1,3-di-tert-butyl-2-[(trimethylsilyl)oxy]benzene, C17H30OSi, (II), and N-(2,6-diisopropylphenyl)-1,1,1-trimethyl-N-(trimethylsilyl)silanamine, C18H35NSi2, (III), are reported. Compound (I) crystallizes in space group P21/c with Z' = 1, (II) in Pnma with Z' = 0.5 and (III) in Cmcm with Z' = 0.25. Consequently, the molecules of (II) are constrained by m and those of (III) by m2m site symmetries. Despite this, both (I) and (II) are distorted towards mild boat conformations, as is typical of 2,6-di-tert-butyl-substituted phenyl compounds, reflecting the high local steric pressure of the flanking alkyl groups. Compound (III) by contrast is planar and symmetric, and this lack of distortion is compatible with the lower steric pressure of the flanking 2,6-diisopropyl substituents. Full Article text
ubs The crystal structures and Hirshfeld surface analyses of a cadmium(II) and a zinc(II) mononuclear complex of the new tetrakis-substituted pyrazine ligand N,N',N'',N'''-[pyrazine-2,3,5,6-tetrayltetrakis(methylene)]tetrakis By scripts.iucr.org Published On :: 2020-02-18 The whole molecule of the cadmium(II) complex, diiodido{N,N',N'',N'''-[pyrazine-2,3,5,6-tetrayltetrakis(methylene)]tetrakis(N-methylaniline)-κ3N2,N1,N6}cadmium(II), [CdI2(C36H40N6)], (I), of the ligand N,N',N'',N'''-[pyrazine-2,3,5,6-tetrayltetrakis(methylene)]tetrakis(N-methylaniline) (L), is generated by a twofold rotation symmetry; the twofold axis bisects the cadmium atom and the nitrogen atoms of the pyrazine ring. The ligand coordinates in a mono-tridentate manner and the cadmium atom has a fivefold CdN3I2 coordination environment with a distorted shape. In the zinc(II) complex, dichlorido{N,N',N'',N'''-[pyrazine-2,3,5,6-tetrayltetrakis(methylene)]tetrakis(N-methylaniline)-κ3N2,N1,N6}zinc(II) dichloromethane 0.6-solvate, [ZnCl2(C36H40N6)]·0.6CH2Cl2, (II), ligand L also coordinates in a mono-tridentate manner and the zinc atom has a fivefold ZnN3Cl2 coordination environment with a distorted shape. It crystallized as a partial dichloromethane solvate. In the crystal of I, the complex molecules are linked by weak C—H⋯I contacts, forming ribbons propagating along [100]. In the crystal of II, the complex molecules are linked by a series of C—H⋯π interactions, forming layers lying parallel to the (1overline{1}1) plane. In the crystals of both compounds there are metal–halide⋯π(pyrazine) contacts present. The Hirshfeld analyses confirm the importance of the C—H⋯halide contacts in the crystal packing of both compounds. Full Article text
ubs Phosphorescent mono- and diiridium(III) complexes cyclometalated by fluorenyl- or phenyl-pyridino ligands with bulky substituents, as prospective OLED dopants By scripts.iucr.org Published On :: 2020-02-18 The crystal structures of tris[9,9-dihexyl-2-(5-methoxypyridin-2-yl-κN)-9H-fluoren-3-yl-κC3]iridium pentane monosolvate, [Ir(C31H38NO)3]·C5H12, (I), di-μ2-chlorido-bis{bis[2-(5-fluoropyridin-2-yl)-9,9-dihexyl-9H-fluoren-3-yl]iridium} pentane 0.3-solvate, [Ir2(C30H35FN)4Cl2]·0.3C5H12, (II), di-μ2-cyanato-bis{bis[9,9-dihexyl-2-(5-methoxypyridin-2-yl)-9H-fluoren-1-yl]iridium} pentane monosolvate, [Ir2(C31H38NO)4(NCO)2(NCO)2]·C5H12, (III), and {μ-N,N'-bis[3,5-bis(trifluoromethyl)phenyl]oxamidato}bis(bis{2-[4-(2,4,6-trimethylphenyl)pyridin-2-yl]phenyl-κ2C1,N'}iridium)–chlorobenzene–pentane (1/2.3/0.4), [Ir2(C20H19N)4(C18H6F12N2O2)]·2.3C6H5Cl·0.4C5H12, (IV), synthesized in the quest for organic light-emitting devices, were determined. The bis-μ2-chloro and bis-μ2-cyanato complexes have ΔΔ and ΛΛ configurations of the distorted octahedral Ir centres in racemic crystals, whereas the oxamido complex has a centrosymmetric (meso) structure with the ΔΛ configuration. The bridging oxamido moiety has a nearly planar anti geometry. All structures show substantial disorder of both host molecules and solvents of crystallization. Full Article text
ubs Crystal structures and Hirshfeld surface analyses of two new tetrakis-substituted pyrazines and a degredation product By scripts.iucr.org Published On :: 2020-02-18 The two new tetrakis-substituted pyrazines, 1,1',1'',1'''-(pyrazine-2,3,5,6-tetrayl) tetrakis(N,N-dimethylmethanamine), C16H32N6, (I) and N,N',N'',N'''-[pyrazine-2,3,5,6-tetrayltetrakis(methylene)]tetrakis(N-methylaniline), C36H40N6, (II), both crystallize with half a molecule in the asymmetric unit; the whole molecules are generated by inversion symmetry. There are weak intramolecular C—H⋯N hydrogen bonds present in both molecules and in (II) the pendant N-methylaniline rings are linked by a C—H⋯π interaction. The degredation product, N,N'-[(6-phenyl-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazine-2,3-diyl)bis(methylene)]bis(N-methylaniline), C28H29N5, (III), was obtained several times by reacting (II) with different metal salts. Here, the 6-phenyl ring is almost coplanar with the planar pyrrolo[3,4-b]pyrazine unit (r.m.s. deviation = 0.029 Å), with a dihedral angle of 4.41 (10)° between them. The two N-methylaniline rings are inclined to the planar pyrrolo[3,4-b]pyrazine unit by 88.26 (10) and 89.71 (10)°, and to each other by 72.56 (13)°. There are also weak intramolecular C—H⋯N hydrogen bonds present involving the pyrazine ring and the two N-methylaniline groups. In the crystal of (I), there are no significant intermolecular contacts present, while in (II) molecules are linked by a pair of C—H⋯π interactions, forming chains along the c-axis direction. In the crystal of (III), molecules are linked by two pairs of C—H⋯π interactions, forming inversion dimers, which in turn are linked by offset π–π interactions [intercentroid distance = 3.8492 (19) Å], forming ribbons along the b-axis direction. Full Article text
ubs Functionalized 3-(5-aryloxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)-1-(4-substituted-phenyl)prop-2-en-1-ones: synthetic pathway, and the structures of six examples By scripts.iucr.org Published On :: 2020-04-21 Five examples each of 3-(5-aryloxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)-1-[4-(prop-2-yn-1-yloxy)phenyl]prop-2-en-1-ones and the corresponding 1-(4-azidophenyl)-3-(5-aryloxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)prop-2-en-1-ones have been synthesized in a highly efficient manner, starting from a common source precursor, and structures have been determined for three examples of each type. In each of 3-[5-(2-chlorophenoxy)-3-methyl-1-phenyl-1H-pyrazol-4-yl]-1-[4-(prop-2-yn-1-yloxy)phenyl]prop-2-en-1-one, C28H21ClN2O3, (Ib), the isomeric 3-[5-(2-chlorophenoxy)-3-methyl-1-phenyl-1H-pyrazol-4-yl]-1-[4-(prop-2-yn-1-yloxy)phenyl]prop-2-en-1-one, (Ic), and 3-[3-methyl-5-(naphthalen-2-yloxy)-1-phenyl-1H-pyrazol-4-yl]-1-[4-(prop-2-ynyloxy)phenyl]prop-2-en-1-one, C32H24N2O3, (Ie), the molecules are linked into chains of rings, formed by two independent C—H⋯O hydrogen bonds in (Ib) and by a combination of C—H⋯O and C—H⋯π(arene) hydrogen bonds in each of (Ic) and (Ie). There are no direction-specific intermolecular interactions in the structure of 1-(4-azidophenyl)-3-[3-methyl-5-(2-methylphenoxy)-1-phenyl-1H-pyrazol-4-yl]prop-2-en-1-one, C26H21N5O2, (IIa). In 1-(4-azidophenyl)-3-[5-(2,4-dichlorophenoxy)-3-methyl-1-phenyl-1H-pyrazol-4-yl]prop-2-en-1-one, C25H17Cl2N5O2, (IId), the dichlorophenyl group is disordered over two sets of atomic sites having occupancies 0.55 (4) and 0.45 (4), and the molecules are linked by a single C—H⋯O hydrogen bond to form cyclic, centrosymmetric R22(20) dimers. Similar dimers are formed in 1-(4-azidophenyl)-3-[3-methyl-5-(naphthalen-2-yloxy)-1-phenyl-1H-pyrazol-4-yl]prop-2-en-1-one, C29H21N5O2, (IIe), but here the dimers are linked into a chain of rings by two independent C—H..π(arene) hydrogen bonds. Comparisons are made between the molecular conformations within both series of compounds. Full Article text
ubs High-resolution cryo-EM reconstructions in the presence of substantial aberrations By scripts.iucr.org Published On :: 2020-03-26 Here, an analysis is performed of how uncorrected antisymmetric aberrations, such as coma and trefoil, affect cryo-EM single-particle reconstruction (SPR) results, and an analytical formula quantifying information loss owing to their presence is inferred that explains why Fourier-shell coefficient-based statistics may report significantly overestimated resolution if these aberrations are not fully corrected. The analysis is validated with reference-based aberration refinement for two cryo-EM SPR data sets acquired with a 200 kV microscope in the presence of coma exceeding 40 µm, and 2.3 and 2.7 Å reconstructions for 144 and 173 kDa particles, respectively, were obtained. The results provide a description of an efficient approach for assessing information loss in cryo-EM SPR data acquired in the presence of higher order aberrations, and address inconsistent guidelines regarding the level of aberrations that is acceptable in cryo-EM SPR experiments. Full Article text
ubs Structures of substrate- and product-bound forms of a multi-domain copper nitrite reductase shed light on the role of domain tethering in protein complexes By scripts.iucr.org Published On :: 2020-04-25 Copper-containing nitrite reductases (CuNiRs) are found in all three kingdoms of life and play a major role in the denitrification branch of the global nitrogen cycle where nitrate is used in place of dioxygen as an electron acceptor in respiratory energy metabolism. Several C- and N-terminal redox domain tethered CuNiRs have been identified and structurally characterized during the last decade. Our understanding of the role of tethered domains in these new classes of three-domain CuNiRs, where an extra cytochrome or cupredoxin domain is tethered to the catalytic two-domain CuNiRs, has remained limited. This is further compounded by a complete lack of substrate-bound structures for these tethered CuNiRs. There is still no substrate-bound structure for any of the as-isolated wild-type tethered enzymes. Here, structures of nitrite and product-bound states from a nitrite-soaked crystal of the N-terminal cupredoxin-tethered enzyme from the Hyphomicrobium denitrificans strain 1NES1 (Hd1NES1NiR) are provided. These, together with the as-isolated structure of the same species, provide clear evidence for the role of the N-terminal peptide bearing the conserved His27 in water-mediated anchoring of the substrate at the catalytic T2Cu site. Our data indicate a more complex role of tethering than the intuitive advantage for a partner-protein electron-transfer complex by narrowing the conformational search in such a combined system. Full Article text
ubs Structures of the substrate-binding protein YfeA in apo and zinc-reconstituted holo forms By scripts.iucr.org Published On :: 2019-08-22 In the structural biology of bacterial substrate-binding proteins (SBPs), a growing number of comparisons between substrate-bound and substrate-free forms of metal atom-binding (cluster A-I) SBPs have revealed minimal structural differences between forms. These observations contrast with SBPs that bind substrates such as amino acids or nucleic acids and may undergo >60° rigid-body rotations. Substrate transfer in these SBPs is described by a Venus flytrap model, although this model may not apply to all SBPs. In this report, structures are presented of substrate-free (apo) and reconstituted substrate-bound (holo) YfeA, a polyspecific cluster A-I SBP from Yersinia pestis. It is demonstrated that an apo cluster A-I SBP can be purified by fractionation when co-expressed with its cognate transporter, adding an alternative strategy to the mutagenesis or biochemical treatment used to generate other apo cluster A-I SBPs. The apo YfeA structure contains 111 disordered protein atoms in a mobile helix located in the flexible carboxy-terminal lobe. Metal binding triggers a 15-fold reduction in the solvent-accessible surface area of the metal-binding site and reordering of the 111 protein atoms in the mobile helix. The flexible lobe undergoes a 13.6° rigid-body rotation that is driven by a spring-hammer metal-binding mechanism. This asymmetric rigid-body rotation may be unique to metal atom-binding SBPs (i.e. clusters A-I, A-II and D-IV). Full Article text
ubs The flavin mononucleotide cofactor in α-hydroxyacid oxidases exerts its electrophilic/nucleophilic duality in control of the substrate-oxidation level By scripts.iucr.org Published On :: 2019-09-24 The Y128F single mutant of p-hydroxymandelate oxidase (Hmo) is capable of oxidizing mandelate to benzoate via a four-electron oxidative decarboxylation reaction. When benzoylformate (the product of the first two-electron oxidation) and hydrogen peroxide (an oxidant) were used as substrates the reaction did not proceed, suggesting that free hydrogen peroxide is not the committed oxidant in the second two-electron oxidation. How the flavin mononucleotide (FMN)-dependent four-electron oxidation reaction takes place remains elusive. Structural and biochemical explorations have shed new light on this issue. 15 high-resolution crystal structures of Hmo and its mutants liganded with or without a substrate reveal that oxidized FMN (FMNox) possesses a previously unknown electrophilic/nucleophilic duality. In the Y128F mutant the active-site perturbation ensemble facilitates the polarization of FMNox to a nucleophilic ylide, which is in a position to act on an α-ketoacid, forming an N5-acyl-FMNred dead-end adduct. In four-electron oxidation, an intramolecular disproportionation reaction via an N5-alkanol-FMNred C'α carbanion intermediate may account for the ThDP/PLP/NADPH-independent oxidative decarboxylation reaction. A synthetic 5-deaza-FMNox cofactor in combination with an α-hydroxyamide or α-ketoamide biochemically and structurally supports the proposed mechanism. Full Article text
ubs Detailed surface analysis of V-defects in GaN films on patterned silicon(111) substrates by metal–organic chemical vapour deposition. Corrigendum By scripts.iucr.org Published On :: 2020-02-01 An error in the article by Gao, Zhang, Zhu, Wu, Mo, Pan, Liu & Jiang [J. Appl. Cryst. (2019), 52, 637–642] is corrected. Full Article text
ubs Synthesis and crystallographic, spectroscopic and computational characterization of the effects of O—R substituents on the torsional[torsion] angle of 3,3',4,4'-substituted biphenyls By journals.iucr.org Published On :: The synthesis, characterization and study of structures from a series of biphenyls substituted at positions 3, 3', 4 and 4' with groups connected to the biphenyl core through oxygen atoms are presented here. The molecular conformation is extensively studied both in the solid as well as in the liquid state, and the effect of different actors (such as packing and chain length) on the torsion angle between aromatic rings is analyzed. Full Article text
ubs Clouded leopard cubs born at National Zoo’s Front Royal campus on Valentine’s Day By insider.si.edu Published On :: Thu, 18 Feb 2010 20:48:06 +0000 Staff had been on a pregnancy watch focused on the 3 1/2-year-old clouded leopard Jao Chu (JOW-chew) for four days. Jao Chu gave birth to the first cub at 6:04 p.m. and the second cub at 6:20 p.m. The post Clouded leopard cubs born at National Zoo’s Front Royal campus on Valentine’s Day appeared first on Smithsonian Insider. Full Article Animals Science & Nature animal births biodiversity conservation conservation biology endangered species extinction Smithsonian's National Zoo
ubs Patience and research may bring lion cubs to the National Zoo By insider.si.edu Published On :: Tue, 23 Mar 2010 17:00:35 +0000 The research and patience has paid off. The sisters, Nababiep and Shera, have spent short periods of time with the male, Luke, individually and simultaneously. This happened only after they each had spent more than a year sniffing Luke through a mesh door (called a “howdy door”). The post Patience and research may bring lion cubs to the National Zoo appeared first on Smithsonian Insider. Full Article Animals Research News Science & Nature captive breeding conservation mammals Smithsonian's National Zoo
ubs Seven lion cubs born recently at the National Zoo By insider.si.edu Published On :: Wed, 13 Oct 2010 13:09:06 +0000 The Smithsonian’s National Zoo recently welcomed two litters of lion cubs over a three-week period – bringing the total number of cubs to seven during the summer of 2010. The post Seven lion cubs born recently at the National Zoo appeared first on Smithsonian Insider. Full Article Animals Science & Nature animal births conservation endangered species mammals Smithsonian's National Zoo
ubs For safety’s sake, Zoo’s lion cubs take first swim By insider.si.edu Published On :: Fri, 29 Oct 2010 12:00:18 +0000 For safety’s sake, the four eight-week-old cubs born to National Zoo lioness Shera were given a swim test on Oct. 26 in the moat of […] The post For safety’s sake, Zoo’s lion cubs take first swim appeared first on Smithsonian Insider. Full Article Animals Science & Nature Spotlight mammals Smithsonian's National Zoo veterinary medicine
ubs Clouded leopard cubs born at Smithsonian Conservation Biology Institute By insider.si.edu Published On :: Thu, 07 Apr 2011 18:07:22 +0000 Sita (SEE-ta), a 2-year-old female clouded leopard at the Smithsonian Conservation Biology Institute in Front Royal, Va., gave birth to these two cubs on Monday, […] The post Clouded leopard cubs born at Smithsonian Conservation Biology Institute appeared first on Smithsonian Insider. Full Article Animals Research News Science & Nature Spotlight conservation conservation biology endangered species mammals Smithsonian's National Zoo
ubs Five cheetah cubs born at Smithsonian Conservation Biology Institute By insider.si.edu Published On :: Wed, 08 Jun 2011 18:45:32 +0000 Five cheetah cubs were born May 28 to 6-year-old Amani at the Smithsonian Conservation Biology Institute in Front Royal, Va. Amani is a dedicated mother according to keepers, who have observed her nursing and grooming the cubs. The post Five cheetah cubs born at Smithsonian Conservation Biology Institute appeared first on Smithsonian Insider. Full Article Animals Science & Nature animal births biodiversity endangered species mammals Smithsonian's National Zoo veterinary medicine
ubs Smithsonian research with DNA barcoding is making seafood substitution easier to catch By insider.si.edu Published On :: Wed, 21 Dec 2011 14:26:40 +0000 Both investigations were carried out through DNA analysis of fish tissue performed in a laboratory using a U.S. Food and Drug Administration protocol that originated largely at the Smithsonian’s National Museum of Natural History. DNA from the fish in question was identified by matching it against a database of DNA fish barcodes that again, has its origins at the Smithsonian. The post Smithsonian research with DNA barcoding is making seafood substitution easier to catch appeared first on Smithsonian Insider. Full Article Marine Science Q & A Science & Nature conservation biology technology
ubs Two Andean bear cubs born Dec. 13 at National Zoo By insider.si.edu Published On :: Thu, 13 Dec 2012 15:23:46 +0000 Two Andean bear cubs born at the National Zoo in the early morning of Dec. 13 to 6-year-old Billie Jean. The post Two Andean bear cubs born Dec. 13 at National Zoo appeared first on Smithsonian Insider. Full Article Animals Science & Nature animal births endangered species Smithsonian's National Zoo veterinary medicine
ubs The crystal structure of the TonB-dependent transporter YncD reveals a positively charged substrate-binding site By scripts.iucr.org Published On :: 2020-04-27 The outer membrane of Gram-negative bacteria is highly impermeable to hydrophilic molecules of larger than 600 Da, protecting these bacteria from toxins present in the environment. In order to transport nutrients across this impermeable membrane, Gram-negative bacteria utilize a diverse family of outer-membrane proteins called TonB-dependent transporters. The majority of the members of this family transport iron-containing substrates. However, it is becoming increasingly clear that TonB-dependent transporters target chemically diverse substrates. In this work, the structure and phylogenetic distribution of the TonB-dependent transporter YncD are investigated. It is shown that while YncD is present in some enteropathogens, including Escherichia coli and Salmonella spp., it is also widespread in Gammaproteobacteria and Betaproteobacteria of environmental origin. The structure of YncD was determined, showing that despite a distant evolutionary relationship, it shares structural features with the ferric citrate transporter FecA, including a compact positively charged substrate-binding site. Despite these shared features, it is shown that YncD does not contribute to the growth of E. coli in pure culture under iron-limiting conditions or with ferric citrate as an iron source. Previous studies of transcriptional regulation in E. coli show that YncD is not induced under iron-limiting conditions and is unresponsive to the ferric uptake regulator (Fur). These observations, combined with the data presented here, suggest that YncD is not responsible for the transport of an iron-containing substrate. Full Article text
ubs New book: “The Subsistence Economies of Indigenous North American Societies: A Handbook” By insider.si.edu Published On :: Tue, 19 Apr 2011 19:27:32 +0000 The new book Subsistence Economies of Indigenous North American Societies provides a comprehensive and in-depth documentation of how Native American societies met the challenges of […] The post New book: “The Subsistence Economies of Indigenous North American Societies: A Handbook” appeared first on Smithsonian Insider. Full Article Anthropology Book Review Research News Science & Nature National Museum of Natural History
ubs The science of panda cubs at the Smithsonian Conservation Biology Institute By insider.si.edu Published On :: Fri, 23 Apr 2010 15:25:21 +0000 When animal care staff at the Smithsonian's National Zoo need to know when to breed their pandas or when to expect a cub they turn to the Endocrine (Hormones) Research Lab at the Zoo's Front Royal, Va. facility. The post The science of panda cubs at the Smithsonian Conservation Biology Institute appeared first on Smithsonian Insider. Full Article Video endangered species giant panda Smithsonian's National Zoo veterinary medicine
ubs Keeper Tracey Barnes talks about the National Zoo’s Andean bear, Billie Jean, and her two new cubs By insider.si.edu Published On :: Mon, 07 Jun 2010 17:29:09 +0000 Keeper Tracey Barnes talks about Billie Jean, an Andean bear, and her two new cubs at the Smithsonian's National Zoo. The post Keeper Tracey Barnes talks about the National Zoo’s Andean bear, Billie Jean, and her two new cubs appeared first on Smithsonian Insider. Full Article Video
ubs Great Cats curator Craig Saffoe discusses his work caring for the National Zoo’s seven frisky lion cubs By insider.si.edu Published On :: Mon, 20 Dec 2010 16:38:54 +0000 What does it take to care for a pride of lions? Go behind the scenes with Great Cats Curator Craig Saffoe as he works with animal keepers and veterinarians to prepare the National Zoo's frisky lion cubs for their public debut. For more about the Zoo's growing pride and to watch them on live webcams: http://nationalzoo.si.edu/Animals/GreatCats/default.cfm?cam=LC4 The post Great Cats curator Craig Saffoe discusses his work caring for the National Zoo’s seven frisky lion cubs appeared first on Smithsonian Insider. Full Article Video biodiversity conservation endangered species mammals Smithsonian's National Zoo veterinary medicine
ubs Many years of research are celebrated in the December 2010 birth of two cheetah cubs at the Smithsonian Conservation Biology Institute By insider.si.edu Published On :: Mon, 07 Feb 2011 17:55:35 +0000 The post Many years of research are celebrated in the December 2010 birth of two cheetah cubs at the Smithsonian Conservation Biology Institute appeared first on Smithsonian Insider. Full Article Animals Research News Science & Nature Video biodiversity conservation endangered species mammals Smithsonian's National Zoo veterinary medicine
ubs Hand-rearing clouded leopard cubs at the Smithsonian Conservation Biology Institute By insider.si.edu Published On :: Thu, 14 Jul 2011 14:49:56 +0000 Animal care staff at the Smithsonian Conservation Biology Institute in Front Royal, Virginia, are hand-rearing the pair of clouded leopard cubs born on March 28, increasing the chances that the cubs will be more successful at breeding later in their life. The post Hand-rearing clouded leopard cubs at the Smithsonian Conservation Biology Institute appeared first on Smithsonian Insider. Full Article Video
ubs Lion cub summer school: Instead of learning their ABCs, the National Zoo’s lion cubs are learning behaviors that will help animal care staff evaluate their health. By insider.si.edu Published On :: Fri, 14 Oct 2011 13:44:51 +0000 School's nearly back in session, but the seven young lions at the Smithsonian's National Zoo have been working hard through the summer months! The post Lion cub summer school: Instead of learning their ABCs, the National Zoo’s lion cubs are learning behaviors that will help animal care staff evaluate their health. appeared first on Smithsonian Insider. Full Article Video mammals Smithsonian's National Zoo veterinary medicine
ubs Lion cubs born at National Zoo By insider.si.edu Published On :: Mon, 27 Jan 2014 16:27:15 +0000 The National Zoo’s Great Cats team celebrated the arrival of its first litter of African lion cubs in four years. On Jan. 24, the Zoo’s […] The post Lion cubs born at National Zoo appeared first on Smithsonian Insider. Full Article Animals Research News Science & Nature Video animal births biodiversity conservation conservation biology endangered species mammals Smithsonian's National Zoo veterinary medicine
ubs Red Panda Cubs Born at Conservation Biology Institute By insider.si.edu Published On :: Wed, 24 Jun 2015 19:02:14 +0000 Seven red panda cubs were born at the Smithsonian Conservation Biology Institute! The cubs were born to mothers Nutmeg, Regan and Leo Mei. Keepers are […] The post Red Panda Cubs Born at Conservation Biology Institute appeared first on Smithsonian Insider. Full Article Animals Science & Nature Video conservation endangered species mammals Smithsonian Conservation Biology Institute Smithsonian's National Zoo veterinary medicine
ubs Hyperuniformity and anti-hyperuniformity in one-dimensional substitution tilings By scripts.iucr.org Published On :: 2019-01-01 This work considers the scaling properties characterizing the hyperuniformity (or anti-hyperuniformity) of long-wavelength fluctuations in a broad class of one-dimensional substitution tilings. A simple argument is presented which predicts the exponent α governing the scaling of Fourier intensities at small wavenumbers, tilings with α > 0 being hyperuniform, and numerical computations confirm that the predictions are accurate for quasiperiodic tilings, tilings with singular continuous spectra and limit-periodic tilings. Quasiperiodic or singular continuous cases can be constructed with α arbitrarily close to any given value between −1 and 3. Limit-periodic tilings can be constructed with α between −1 and 1 or with Fourier intensities that approach zero faster than any power law. Full Article text
ubs Simulink - Subsystem Reference block's position changes on loading or during synchronization of contents By in.mathworks.com Published On :: Sat, 09 May 2020 00:53:50 +0000 In certain scenarios, a Subsystem Reference block changes its position. It can happen during: Loading of top model which contains the Subsystem Reference block Synchronization of Subsystem Reference block's contentsConverting a subsystem to Subsystem Reference block This bug exists in the following release(s): R2019b Interested in Upgrading? Full Article
ubs Synthesis of N-substituted 3-(2-aryl-2-oxoethyl)-3-hydroxyindolin-2-ones and their conversion to N-substituted (E)-3-(2-aryl-2-oxoethylidene)indolin-2-ones: synthetic sequence, spectroscopic characterization and structures of By scripts.iucr.org Published On :: 2020-04-20 An operationally simple and time-efficient approach has been developed for the synthesis of racemic N-substituted 3-(2-aryl-2-oxoethyl)-3-hydroxyindolin-2-ones by a piperidine-catalysed aldol reaction between aryl methyl ketones and N-alkylisatins. These aldol products were used successfully as strategic intermediates for the preparation of N-substituted (E)-3-(2-hetaryl-2-oxoethylidene)indolin-2-ones by a stereoselective dehydration reaction under acidic conditions. The products have all been fully characterized by 1H and 13C NMR spectroscopy, by mass spectrometry and, for a representative selection, by crystal structure analysis. In each of (RS)-1-benzyl-3-hydroxy-3-[2-(4-methoxyphenyl)-2-oxoethyl]indolin-2-one, C24H21NO4, (Ic), and (RS)-1-benzyl-3-{2-[4-(dimethylamino)phenyl]-2-oxoethyl}-3-hydroxyindolin-2-one, C25H24N2O3, (Id), inversion-related pairs of molecules are linked by O—H⋯O hydrogen bonds to form R22(10) rings, which are further linked into chains of rings by a combination of C—H⋯O and C—H⋯π(arene) hydrogen bonds in (Ic) and by C—H⋯π(arene) hydrogen bonds in (Id). The molecules of (RS)-1-benzyl-3-hydroxy-3-[2-oxo-2-(pyridin-4-yl)ethyl]indolin-2-one, C22H18N2O3, (Ie), are linked into a three-dimensional framework structure by a combination of O—H⋯N, C—H⋯O and C—H⋯π(arene) hydrogen bonds. (RS)-3-[2-(Benzo[d][1,3]dioxol-5-yl)-2-oxoethyl]-1-benzyl-3-hydroxyindolin-2-one, C24H19NO5, (If), crystallizes with Z' = 2 in the space group Poverline{1} and the molecules are linked into complex sheets by a combination of O—H⋯O, C—H⋯O and C—H⋯π(arene) hydrogen bonds. In each of (E)-1-benzyl-3-[2-(4-fluorophenyl)-2-oxoethylidene]indolin-2-one, C23H16FNO2, (IIa), and (E)-1-benzyl-3-[2-oxo-2-(thiophen-2-yl)ethylidene]indolin-2-one, C21H15NO2S, (IIg), the molecules are linked into simple chains by a single C—H⋯O hydrogen bond, while those of (E)-1-benzyl-3-[2-oxo-2-(pyridin-4-yl)ethylidene]indolin-2-one, C22H16N2O2, (IIe), are linked by three C—H⋯O hydrogen bonds to form sheets which are further linked into a three-dimensional structure by C—H⋯π(arene) hydrogen bonds. There are no hydrogen bonds in the structures of either (E)-1-benzyl-3-[2-(4-methoxyphenyl)-2-oxoethylidene]indolin-2-one, C24H19NO3, (IIc), or (E)-1-benzyl-5-chloro-3-[2-(4-chlorophenyl)-2-oxoethylidene]indolin-2-one, C23H15Cl2NO2, (IIh), but the molecules of (IIh) are linked into chains of π-stacked dimers by a combination of C—Cl⋯π(arene) and aromatic π–π stacking interactions. Full Article text
ubs Carcinogens and Anticarcinogens in the Human Diet - A Comparison of Naturally Occurring and Synthetic Substances By feedproxy.google.com Published On :: Thu, 15 Feb 1996 06:00:00 GMT Cancer-causing chemicals that occur naturally in foods are far more numerous in the human diet than synthetic carcinogens, yet both types are consumed at levels so low that they currently appear to pose little threat to human health, a committee of the National Research Council said in a report released today. Full Article
ubs New Report Calls for Coordinated, Multidecade National Effort to Reduce Negative Attitudes and Behavior Toward People With Mental and Substance Use Disorders By feedproxy.google.com Published On :: Wed, 20 Apr 2016 05:00:00 GMT The U.S. Department of Health and Human Services (HHS) should lead efforts among federal partners and stakeholders to design, implement, and evaluate a multipronged, evidence-based national strategy to reduce stigma toward people with mental and substance use disorders, says a new report from the National Academies of Sciences, Engineering, and Medicine. Full Article
ubs Substantial Gap Exists Between Demand for Organ Transplants in U.S. and Number of Transplants Performed - New Report Offers Ethical, Regulatory, and Policy Framework for Research to Increase Quantity & Quality of Organs For Transplantation, Save Lives By feedproxy.google.com Published On :: Tue, 10 Oct 2017 05:00:00 GMT The number of patients in the U.S. awaiting organ transplantation outpaces the amount of transplants performed in the U.S., and many donated organs are not transplanted each year due to several factors, such as poor organ function, says a new report from the National Academies of Sciences, Engineering, and Medicine. Full Article
ubs VA Provides Mental Health Care to Veterans of Recent Iraq and Afghanistan Wars of Comparable or Superior Quality to Other Providers, Yet Substantial Unmet Need Remains By feedproxy.google.com Published On :: Wed, 31 Jan 2018 06:00:00 GMT While the U.S. Department of Veterans Affairs (VA) provides mental health care of comparable or superior quality to care provided in private and non-VA public sectors, accessibility and quality of services vary across the VA health system, leaving a substantial unmet need for mental health services among veterans of the recent wars in Afghanistan and Iraq, says a new congressionally mandated report from the National Academies of Sciences, Engineering, and Medicine. Full Article
ubs EPA’s IRIS Program Has Made Substantial Progress, Says New Report By feedproxy.google.com Published On :: Wed, 11 Apr 2018 05:00:00 GMT The U.S. Environmental Protection Agency’s (EPA) Integrated Risk Information System (IRIS) program has made “substantial progress” in implementing recommendations outlined in past reports by the National Academies of Sciences, Engineering, and Medicine, improving the program’s overall scientific and technical performance, says a new Academies report. Full Article
ubs Current Evidence Supports Classification of Red Wolf as a Distinct Species, Report Says, Mexican Gray Wolf Is a Valid Subspecies of Gray Wolf By feedproxy.google.com Published On :: Thu, 28 Mar 2019 05:00:00 GMT Current evidence supports the classification of the contemporary red wolf as a distinct species of wolf, although additional genomic evidence from historic wolf specimens could change that assessment, says Evaluating the Taxonomic Status of the Mexican Gray Wolf and the Red Wolf, a new report from the National Academies of Sciences, Engineering, and Medicine. Full Article
ubs Reducing fishing in marginal areas could substantially reduce the footprint and impact of seabed fishing By ec.europa.eu Published On :: Wed, 18 Dec 2013 08:55:05 GMT Seabed fishing grounds in the UK are made up of intensively fished core areas surrounded by more rarely used marginal areas, new research shows. Excluding these margins, which contain only 10% of the total fishing activity, approximately halves the total area of fishing grounds. Thus reducing the fishing footprint by closing the marginal areas will disproportionately reduce the seabed impact of fishing activity. Full Article
ubs Serious flaws found in multiple smart home hubs: Is your device among them? By feedproxy.google.com Published On :: Wed, 22 Apr 2020 07:30:01 +0000 In worst-case scenarios, some vulnerabilities could even allow attackers to take control over the central units and all peripheral devices connected to them The post Serious flaws found in multiple smart home hubs: Is your device among them? appeared first on WeLiveSecurity Full Article Vulnerability
ubs Getting the most from substance flow analyses By ec.europa.eu Published On :: Thu, 18 Feb 2010 16:38:36 GMT New research from Sweden identifies the characteristics of substance flow analyses that make them useful to policy makers. Substance flow analyses that focus on measuring rather than modelling pollution and which are aligned to existing measures are more likely to influence policy. Full Article
ubs The future of subsidy payments for organic farming By ec.europa.eu Published On :: Thu, 23 Jul 2009 15:31:21 +0100 Despite the current economic situation, organic farming is a growth sector in the EU. A recent EU-funded study suggests support payments from the amended 2003 Common Agricultural Policy (CAP) for organic farming will continue to play an important role in Western European countries and will become increasingly significant in new Member States. Full Article
ubs Plastic components of WEEE contain hazardous substances By ec.europa.eu Published On :: Wed, 20 Jul 2011 14:31:12 +0100 A report has revealed that the plastic components of waste electrical and electronic equipment (WEEE) can contain significant amounts of hazardous substances, such as lead, mercury or certain flame retardants. The findings suggest that the plastics from some types of WEEE need to be treated as hazardous waste by waste managers and recyclers. Full Article
ubs Recycling construction and demolition waste has substantial environmental benefits By ec.europa.eu Published On :: Thu, 23 May 2013 11:53:53 +0100 The environmental benefits of recycling construction and demolition waste (CDW) are considerable, even after accounting for the impacts of the recycling process itself, research confirms. By assessing CO2 and energy use at a large-scale recycling plant in Portugal reseachers have shown that, over its 60-year lifespan, the CO2 emissions prevented will be ten times as much as those produced, and eight times as much energy will be saved, than is used. Full Article
ubs Ericsson predicts 1 billion 5G subscriptions in 2023 By cio.economictimes.indiatimes.com Published On :: 2017-11-29T15:00:06+05:30 5G will cover more than 20 percent of the global population six years from now, according to the latest Ericsson Mobility Report Full Article
ubs Public subsidies for electric vehicle fleets are important for adoption By ec.europa.eu Published On :: Thu, 22 Jan 2015 9:23:19 GMT Public subsidies are important in encouraging organisations to trial and expand electric vehicle fleets, according to new research. The study, based on interviews and reports from 17 organisations, found that the opportunity to test new technology was the most important factor in deciding to trial electric vehicles. However, some smaller independent companies chose not to expand their fleet because of the expense. Full Article
ubs Reforming subsidies that harm the environment By ec.europa.eu Published On :: Thu, 25 Mar 2010 16:01:35 +0100 Subsidies support economic sectors and grant advantages to consumers, but can harm the environment. A new study has tested a number of existing tools for assessing environmentally harmful subsidies (EHS), developed a comprehensive methodology for identifying and analysing EHS and highlighted opportunities for reforming them. Full Article
ubs Gautam Adani woos Amazon and Google with Indian data hubs By cio.economictimes.indiatimes.com Published On :: 2019-07-11T15:00:00+05:30 Adani expects to invest Rs 700 billion to build data parks in India over the next two decades. Full Article
ubs Loss of wild pollinators could substantially reduce soybean yields By ec.europa.eu Published On :: Thu, 27 Mar 2014 9:23:19 GMT Pollination by wild insects and honey bees improves soybean yield by 18%, new research has indicated. This equates to an extra 331.6 kg of seeds per hectare, boosting the value of the global crop by €12.74 billion. Encouraging insect pollination could therefore reduce the destruction of natural ecosystems to make way for soybean cultivation, the researchers say. Full Article
ubs Bear hunting's hidden impacts on cubs is highlighted in new study By ec.europa.eu Published On :: Thu, 21 May 2015 9:23:19 GMT Hunting has obvious impacts on wild populations. However, new research concludes that for Scandinavian brown bears (Ursus arctos), it also contributes to the killing of cubs by adult males to increase the male's chances of mating with the cubs' mother. The researchers say that this indirect effect of hunting should be considered when developing sustainable hunting quotas and management plans. Full Article