New gliding mammaliaforms from the Jurassic.

Stem mammaliaforms are Mesozoic forerunners to mammals, and they offer critical evidence for the anatomical evolution and ecological diversification during the earliest mammalian history. Two new eleutherodonts from the Late Jurassic period have skin membranes and skeletal features that are adapted for gliding. Characteristics of their digits provide evidence of roosting behaviour, as in dermopterans and bats, and their feet have a calcaneal calcar to support the uropagatium as in bats. The new volant taxa are phylogenetically nested with arboreal eleutherodonts. Together, they show an evolutionary experimentation similar to the iterative evolutions of gliders within arboreal groups of marsupial and placental mammals. However, gliding eleutherodonts possess rigid interclavicle-clavicle structures, convergent to the avian furculum, and they retain shoulder girdle plesiomorphies of mammaliaforms and monotremes. Forelimb mobility required by gliding occurs at the acromion-clavicle and glenohumeral joints, is different from and convergent to the shoulder mobility at the pivotal clavicle-sternal joint in marsupial and placental gliders.

New evidence for mammaliaform ear evolution and feeding adaptation in a Jurassic ecosystem.

Stem mammaliaforms are forerunners to modern mammals, and they achieved considerable ecomorphological diversity in their own right. Recent discoveries suggest that eleutherodontids, a subclade of Haramiyida, were more species-rich during the Jurassic period in Asia than previously recognized. Here we report a new Jurassic eleutherodontid mammaliaform with an unusual mosaic of highly specialized characteristics, and the results of phylogenetic analyses that support the hypothesis that haramiyidans are stem mammaliaforms. The new fossil shows fossilized skin membranes that are interpreted to be for gliding and a mandibular middle ear with a unique character combination previously unknown in mammaliaforms. Incisor replacement is prolonged until well after molars are fully erupted, a timing pattern unique to most other mammaliaforms. In situ molar occlusion and a functional analysis reveal a new mode of dental occlusion: dual mortar-pestle occlusion of opposing upper and lower molars, probably for dual crushing and grinding. This suggests that eleutherodontids are herbivorous, and probably specialized for granivory or feeding on soft plant tissues. The inferred dietary adaptation of eleutherodontid gliders represents a remarkable evolutionary convergence with herbivorous gliders in Theria. These Jurassic fossils represent volant, herbivorous stem mammaliaforms associated with pre-angiosperm plants that appear long before the later, iterative associations between angiosperm plants and volant herbivores in various therian clades.

A Jurassic eutherian mammal and divergence of marsupials and placentals.

Placentals are the most abundant mammals that have diversified into every niche for vertebrates and dominated the world's terrestrial biotas in the Cenozoic. A critical event in mammalian history is the divergence of eutherians, the clade inclusive of all living placentals, from the metatherian-marsupial clade. Here we report the discovery of a new eutherian of 160 Myr from the Jurassic of China, which extends the first appearance of the eutherian-placental clade by about 35 Myr from the previous record, reducing and resolving a discrepancy between the previous fossil record and the molecular estimate for the placental-marsupial divergence. This mammal has scansorial forelimb features, and provides the ancestral condition for dental and other anatomical features of eutherians.

A tetra-nuclear cobalt(III) cluster with 2-(hydroxy-meth-yl)pyridine ligands.

In the title compound, tetra-kis[µ(3)-(2-pyrid-yl)methano-lato]tetra-kis[bromido(methanol)cobalt(III)] tetra-bromide 2-(hydroxy-meth-yl)pyridine tetra-solvate dihydrate, [Co(4)Br(4)(C(6)H(6)NO)(4)(CH(3)OH)(4)]Br(4)·4C(6)H(7)NO(4)·2H(2)O, the cation comprises a [Co(4)O(4)] cubane-type core ( symmetry). The four Co(III) ions and bridging O atoms from four (2-pyrid-yl)methano-late anions are located at alternating vertices of the cube, with bromide ions and methanol ligands on the exterior of the core, completing a distorted octa-hedral geometry. The structure is stablized by inter-molecular O-H⋯Br and O-H⋯O inter-actions.

Incomplete convergence of gliding mammal skeletons.

Ecology and biomechanics play central roles in the generation of phenotypic diversity. When unrelated taxa invade a similar ecological niche, biomechanical demands can drive convergent morphological transformations. Thus, examining convergence helps to elucidate the key catalysts of phenotypic change. Gliding mammals are often presented as a classic case of convergent evolution because they independently evolved in numerous clades, each possessing patagia ("wing" membranes) that generate lift during gliding. We use phylogenetic comparative methods to test whether the skeletal morphologies of the six clades of extant gliding mammals demonstrate convergence. Our results indicate that glider skeletons are convergent, with glider groups consistently evolving proportionally longer, more gracile limbs than arborealists, likely to increase patagial surface area. Nonetheless, we interpret gliders to represent incomplete convergence because (1) evolutionary model-fitting analyses do not indicate strong selective pressures for glider trait optima, (2) the three marsupial glider groups diverge rather than converge, and (3) the gliding groups remain separated in morphospace (rather than converging on a single morphotype), which is reflected by an unexpectedly high level of morphological disparity. That glider skeletons are morphologically diverse is further demonstrated by fossil gliders from the Mesozoic Era, which possess unique skeletal characteristics that are absent in extant gliders. Glider morphologies may be strongly influenced by factors such as body size and attachment location of patagia on the forelimb, which can vary among clades. Thus, convergence in gliders appears to be driven by a simple lengthening of the limbs, whereas additional skeletal traits reflect nuances of the gliding apparatus that are distinct among different evolutionary lineages. Our unexpected results add to growing evidence that incomplete convergence is prevalent in vertebrate clades, even among classic cases of convergence, and they highlight the importance of examining form-function relationships in light of phylogeny, biomechanics, and the fossil record.

Phenothiazine-anthraquinone donor-acceptor molecules: synthesis, electronic properties and DFT-TDDFT computational study.

Two donor-acceptor molecules with different pi-electron conjugative units, 1-((10-methyl-10H-phenothiazin-3-yl)ethynyl)anthracene-9,10-dione (AqMp) and 1,1'-(10-methyl-10H-phenothiazine-3,7-diyl)bis(ethyne-2,1-diyl)dianthracene-9,10-dione (Aq2Mp), have been synthesized and investigated for their photochemical and electrochemical properties. Density functional theory (DFT) calculations provide insights into their molecular geometry, electronic structures, and properties. These studies satisfactorily explain the electrochemistry of the two compounds and indicate that larger conjugative effect leads to smaller HOMO-LUMO gap (Eg) in Aq2Mp. Both compounds show ICT and pi --> pi* transitions in the UV-visible range in solution, and Aq2Mp has a bathochromic shift and shows higher oscillator strength of the absorption, which has been verified by time-dependent DFT (TDDFT) calculations. The differences between AqMp and Aq2Mp indicate that the structural and conjugative effects have great influence on the electronic properties of the molecules.

Ligand-to-metal ratio controlled assembly of nanoporous metal-organic frameworks.

Two bilayered metal-organic frameworks with nanoporous channels were synthesized at different ligand-to-metal ratios, which demonstrated an interesting crystal-to-crystal transformation property and a special fluorescent response to the different guest molecules included.

Porous material for absorption and luminescent detection of aromatic molecules in water.

A two-dimensional porous framework, which was formed from neutral discrete hexanuclear copper clusters via self-assembly, exhibited highly selective absorption of aromatic molecules in water with special fluorescent response.

Mammalian evolution. Evolutionary development in basal mammaliaforms as revealed by a docodontan.

A new Late Jurassic docodontan shows specializations for a subterranean lifestyle. It is similar to extant subterranean golden moles in having reduced digit segments as compared to the ancestral phalangeal pattern of mammaliaforms and extant mammals. The reduction of digit segments can occur in mammals by fusion of the proximal and intermediate phalangeal precursors, a developmental process for which a gene and signaling network have been characterized in mouse and human. Docodontans show a positional shift of thoracolumbar ribs, a developmental variation that is controlled by Hox9 and Myf5 genes in extant mammals. We argue that these morphogenetic mechanisms of modern mammals were operating before the rise of modern mammals, driving the morphological disparity in the earliest mammaliaform diversification.

Mammalian evolution. An arboreal docodont from the Jurassic and mammaliaform ecological diversification.

A new docodontan mammaliaform from the Middle Jurassic of China has skeletal features for climbing and dental characters indicative of an omnivorous diet that included plant sap. This fossil expands the range of known locomotor adaptations in docodontans to include climbing, in addition to digging and swimming. It further shows that some docodontans had a diet with a substantial herbivorous component, distinctive from the faunivorous diets previously reported in other members of this clade. This reveals a greater ecological diversity in an early mammaliaform clade at a more fundamental taxonomic level not only between major clades as previously thought.

A three dimensional porous metal-organic framework [Fe4L6.(DMF)3.(H2O)10] constructed from neutral discrete Fe4L6 pyramids [H2L = 1,3-benzodihydroxamix acid].

A 3-D porous zeolite-like metal-organic framework surviving guest removal is assembled from a well-defined tetrahedral Fe(4)L(6) cavity by the cooperativity of hydrogen bonds and [small pi]-[small pi] stacking.

A novel pyramidal multiple alkali metal cluster [K3(H2O)]3+ stabilized within a capsule containing 16-nitrogen donors.

A novel multiple alkali metal cluster K3(H2O)]3+ interior within a high-symmetry cubic capsule containing 16-nitrogen donors is achieved via self-assembly from twenty components.

Lanthanide heterometallic molecular squares Ru2-Ln2 exhibiting sensitized near-infrared emission.

New lanthanide heterometallic molecular squares functionalized with Ru-bipy antenna chromophore Ru2-Ln2 exhibit sensitized near-infrared emission upon photo-excitation of the Ru-centered antenna at 420 nm.

Preparation and electrochemistry of azobenzene self-assembled monolayers on gold--long range tunneling and end-group hydrogen bonding effect.

A series of thiol-functionalied azobenzene derivatives (RAzoCnSH: R=H for n=3-6, abbreviated as AzoCnSH; R=CH(3)CONH for n=4, abbreviated as aaAzoC4SH) on gold electrodes were prepared and their self-assembly and electrochemical properties were studied by cyclic voltammetry. They all formed uniform and reproducible self-assembled monolayers (SAMs) on gold and showed well-behaved voltammetric responses in aqueous solution. Both the length of the alkyl chain spacer and the H-bonding of the end acetamino group had effects on the stability and the electrochemical kinetics of the SAMs, and the effect of the H-bonding was dominant. The surface coverage of the SAMs (AzoCnSH) is gradually increased with an increase of the alkyl chain spacer length, whereas the presence of the terminal acetamino group leads to a greater increase of the surface coverage. At a low scan rate, voltammetric responses corresponding to an irreversible two-electron, two-proton reduction/oxidation of the trans-azobenzene redox center were obtained in the range of +300 mV and -800 mV, which exhibited very large peak-to-peak splitting. At a high scan rate of 500 mV/s, two steps of reversible one-electron, one-proton reduction/oxidation corresponding to the cis-isomer in azobenzene-thiol SAMs (n is odd) was clearly observed between +300 and -200 mV. The apparent electron-transfer rate is decreased with increasing distance between the azobenzene redox center and the gold electrode. The existence of the end acetamino group which restricted the conformational change during the redox process also led to a decrease of the standard rate constant, and this restriction effect is more predominant than the distance effect.

Self-assembly of L-cysteine-copper(II)/copper(I) multilayer thin films on gold.

Self-assembled multilayer thin films have been prepared on Au substrate by alternate surface derivatization with L-cysteine hydrochloride and cupric perchlorate. The layer-by-layer structure at each step of multilayer formation was investigated by X-ray photoelectron spectroscopy. The measurements indicate that there are two structure modes in the multilayers. One is that Cu(2+) sandwiches between two amino acid groups. The other one is that Cu(+) is bonded through disulfide and thiolate. This process is also confirmed by cyclic voltammetry of Cu ion at different self-assembled multilayers. Steps further on will lead to repeated multilayer films.

Study on self-assembled monolayers of functionalized azobenzene thiols on gold: XPS, electrochemical properties, and surface-enhanced Raman spectroscopy.

Self-assembled monolayers (SAMs) of 4-acetamino-4'-(4-mercaptobutoxy)azobenzene (CH3)CONH-ph-N=N-ph-O(CH2)(4)SH, abbr. aaAzoC4SH) and 4-mercaptobutoxy azobenzene (ph-N=N-ph-O(CH2)(4)SH, abbr. AzoC4SH) on a gold surface have been studied by X-ray photoelectron spectroscopy (XPS), FT Raman spectroscopy, and electrochemistry. A surface-enhanced Raman scattering (SERS)-active system with a "sandwiched" structure of Ag/R-Azo-C4S-/Au was conveniently obtained by the method of Tollen's test. The relationship between the SERS effect and the structural nature of the system indicates that the enhancement correlates to both the silver islands above and the gold substrate underneath. The redox behaviors of the self-assembly on gold electrodes showed that the SAMs of the two compounds exhibit well-behaved voltammetric responses in a Britton-Robinson buffer corresponding to the irreversible two-electron, two-proton reduction-oxidation of azobenzene. The apparent electron-transfer rate kinetics is very sluggish, and the rate constant k(app) of aaAzoC4SH/Au (1.34 x 10(-6) s(-1)) is lower than that of AzoC4SH/Au (1.63 x 10(-4) s(-1)), which may be attributed to the different spatial restriction of close-packing structures on the conformational change accompanied by electron and proton transfer in the SAMs.

Structural, morphological, and magnetic study of nanocrystalline cobalt-nickel-copper particles.

Nanocrystalline Co(x)Ni(y)Cu(100-x-y) particles were synthesized by the reduction of metal acetates in a mixture of polyol and Tween 80. Inductively coupled plasma (ICP) analysis revealed that the actual wt% of Co, Ni, and Cu in these nanoparticles was nearly the same as in the starting solutions. The structures of the particles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED) spectroscopy, and vibrating sample magnetometry (VSM). The results of XRD and VSM confirmed that there was no metastable alloying in the particles. The particles were composites, consisting of nanoscale crystallites of face-centered cubic (fcc) Cu, face-centered cubic (fcc) Ni, and face-centered cubic (fcc) Co. During preparation the nucleation of Cu occurred first; then small Cu nuclei acted as cores for the precipitation of Co and Ni. The particles showed an increase in saturation magnetization (M(s)) as the concentration of Co or Ni in the particles was increased. The changes of both M(s) and coercivity of the particles with increasing annealing temperatures were studied. The coercivity of the particles was very high; it could reach as high as 489 Oe for Co34.3Ni31.2Cu34.5) .

Surface-enhanced Raman scattering (SERS) from different azobenzene self-assembled monolayers and sandwiches.

Self-assembled monolayers (SAMs) of functionalized azobenzene thiols (RAzoCnSH, n=3-6 for R=H, abbreviated as AzoCnSH; and n=4 for R=CH(3)CONH, abbreviated as aaAzoC4SH) on different substrates RAzoCnSz.sbnd;z.sfnc;S (S represents substrates of vacuum-deposited gold (Au), silver foil (Ag), HNO(3) etched silver foil (EAg), and silver mirror (mAg)) have been studied by SERS in the near-infrared region. SERS of the SAMs on EAg and/or mAg exhibit SERS effects that vary with etching time and/or deposition time. The most appropriate time is 5 s for etching in 1:1 HNO(3) and 40 s for deposition in 0.1 M Ag(NH(3))(2)NO(3). Further, a layer of Ag mirror was conveniently deposited on the top of the SAMs on different substrates, yielding a more efficient SERS-active system possessing a "sandwiched" structure of mAgz.sfnc;RAzoCnS-z.sfnc;S. An appropriate surface roughness is required for the strongest SERS effect. Scanning electron microscopy (SEM) indicates that there exist a large number of projects around 100 nm on the surface showing the strongest SERS effect. When the surface roughness is decreased or increased, the SERS effect decreases sharply. The relationship between the SERS effect and the structural nature was investigated and showed that the enhancement factor decays exponentially with increasing in distances of the azobenzene group from the underlying substrate or the overlying silver mirror. This result reveals that the SERS effect may be the result of the electromagnetic coupling effect between two metal layers.

Earliest evolution of multituberculate mammals revealed by a new Jurassic fossil.

Multituberculates were successful herbivorous mammals and were more diverse and numerically abundant than any other mammal groups in Mesozoic ecosystems. The clade also developed diverse locomotor adaptations in the Cretaceous and Paleogene. We report a new fossil skeleton from the Late Jurassic of China that belongs to the basalmost multituberculate family. Dental features of this new Jurassic multituberculate show omnivorous adaptation, and its well-preserved skeleton sheds light on ancestral skeletal features of all multituberculates, especially the highly mobile joints of the ankle, crucial for later evolutionary success of multituberculates in the Cretaceous and Paleogene.

Co(II) and Ni(II) complexes based on anthraquinone-1,4,5,8-tetracarboxylic acid (H4AQTC): canted antiferromagnetism and slow magnetization relaxation in {[Co2(AQTC)(H2O)6]·6H2O}.

Three coordination polymers {[Co2(AQTC)(H2O)6]·6H2O}n (1), {[M2(AQTC)(bpym)(H2O)6]·6H2O}n (M = Co(2), Ni(3)) have been synthesized and structurally characterized, where H4AQTC is anthraquinone-1,4,5,8-tetracarboxylic acid and bpym is 2,2'-bipyrimidine. Complex 1 features a 3-D structure, where layers of Co2(AQTC) are cross-linked by Co-H2O chains. Complexes 2 and 3 are isostructural and display 1-D chain structures. The chains are connected through hydrogen-bonding interactions to form 3-D supramolecular structures. Magnetic properties of these complexes are investigated. Compound 1 shows canted antiferromagnetism and slow relaxation below 4.0 K. For complexes 2 and 3, dominant antiferromagnetic interactions are observed. The luminescent properties of the three complexes are investigated as well.