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Five novel copper(II) coordination polymers containing cyanoacetate (cna) anion with various N,N′-ditopic spacers [Cu(cna)2(pyz)]n (1), [Cu(cna)2(bpy)(H2O)2]n (2), [Cu(cna)2(dpe)]n (3), [Cu(cna)2(dpe)]n(H2O)n (4), and [Cu(cna)2(bpa)]n (5) (when pyz = pyrazine, bpy = 4,4′-bipyridyl, dpe = 1,2-di(4-pyridyl)ethylene, and bpa = 1,2-di(4-pyridyl)ethane) were structurally and spectroscopically characterized. Compound 1 shows a two-dimensional (2D) sheet structure constructed from μ2-1,3(syn,anti) coordinative mode of cyanoacetate and μ2-pyz linking adjacent Cu(II) centers. Compound 2 exhibits a one-dimensional (1D) polymeric chain which is formed by μ2-bpy bridging between [Cu(cna)2(H2O)2] units, whereas compounds 3–5 reveal 1D ladder-like structures which are built from double-μ2-dpe/bpa spacers connecting neighboring Cu(II) cyanoacetate dimers. Weak interactions such as hydrogen bonding and N···π and/or C–H···π interactions join the adjacent layers of 1 or polymeric chains of 2–5 to stabilize overall supramol...

Two uranyl tungstates, Cs4[(UO2)4(WO5)(W2O8)O2] (CsUW-1) and Cs4[(UO2)7(WO5)3O3] (CsUW-2), were obtained via the high-temperature solid-state synthesis method by reacting uranyl nitrate with WO3 in the presence of cesium nitrate. CsUW-1 crystallizes in space group P21/n, adopting a two-dimensional (2D) sheet structure. CsUW-2 forms a three-dimensional (3D) framework constructed by complex 2D sheets linked by cation–cation interactions of UO22+ groups. The cation–cation interactions fragment presented in CsUW-2 involves the 2D → 3D transformation of the uranyl tungstate network and acts as an intermediate part by bridging the structures of CsUW-1 and CsUW-2. We demonstrate that the chemical and structural transformation from CsUW-1 to CsUW-2 is possible via adding a suitable amount of UO3 oxide. In addition, the differential scanning calorimetry-thermogravimetric technique was carried out to gain insight into the thermal behavior of the synthesized compounds. Raman spectra of titled compounds were obtained...

Amyloidosis is a rare group of diseases related to extracellular deposition of proteins in an insoluble beta-pleated sheet structure presenting a characteristic apple-green birefringence under polarized light after Congo red staining. Thirty types of proteins are known to cause amyloidosis. The accurate identification of the amyloid protein is of paramount importance since it is a key step for the clinical management and personalized treatment. Amyloid typing is usually based on immunohistochemistry and immunofluorescence on tissular sections. This approach has several limits leading to a subtyping failure rate of 15 to 58% of cases. To overcome these difficulties, proteomic methods have been developed to characterize directly the amyloid protein. The most advanced technique carried out on fixed and paraffin-embedded tissue consists of laser microdissection followed by mass spectrometry. The type of amyloidosis can be determined in more than 95% of cases. However, the experience for this technique is very limited apart from the Mayo Clinic (Rochester, United States). In France, a very close proteomic assay has been implemented in the department of pathology of Foch Hospital with similar results. The introduction of proteomics in clinical practice represents a major improvement for typing amyloidosis. In this article, we discuss the benefits and limits of the different techniques used for amyloid classification and we briefly report our proteomic results.

Clay reduces fluidity and increases fluidity loss of concrete added with polycarboxylate superplasticiser. Sometimes it cuts down concrete durability. Fluidity of clay–cement paste with the addition of polycarboxylate superplasticiser, adsorption amount of polycarboxylate superplasticiser and ζ-potential has been tested to understand the effect of polycarboxylate superplasticiser on cement–clay systems. The results show that cement particles have a smooth surface; there are lots of layered or sheet structure existing on the surface of clay; when the particle size distribution is little different, the specific surface area of clay is 17 times that of cement; it is the reason why polycarboxylate superplasticiser adsorption on clay is much greater than that of cement. Initial adsorption amount and equilibrium adsorption amount of polycarboxylate superplasticiser on clay are 3–4 times that of cement; strong PC adsorption of clay is the main reason why the presence of clay reduces fluidity and increase...

The title compound shows two packing polymorphs, in which the mol­ecular structures are planar and essentially similar. One crystal shows inter­molecular C—H⋯O and π–π inter­actions, while the other crystal exhibits several modes of inter­molecular C—H⋯O inter­actions., The title compound, C11H13NO6, shows two polymorphs, orange and yellow forms, both of which crystallize in the space group P21/c. The mol­ecular structures in the two polymorphs are essentially similar and adopt a planar structure, the maximum deviations for the non-H atoms being 0.1836 (13) and 0.1276 (13) Å, respectively, for the orange and yellow forms. In the orange crystal, mol­ecules are linked by an inter­molecular C—H⋯O inter­action into a helical chain along the b-axis direction. The chains are stacked along the c axis through a π–π inter­action [centroid–centroid distance = 3.6087 (11) Å], forming a layer parallel to the bc plane. In the yellow crystal, mol­ecules are connected through C—H⋯O inter­actions into a sheet structure parallel to (-302). No significant π–π inter­action is observed. The unit-cell volume of the orange crystal is larger than that of the yellow one, and this accounts for the predominant growth of the yellow crystal.

To further explore the coordination ability of an multi-functional ligand 2-(p-bromophenyl)-1H-imidazole-4,5-dicarboxylic acid (p-BrPhH3IDC), two metal-organic frameworks [Mn(μ2-p-BrPhH2IDC)2]n (I) and {[Pb(μ2-p-BrPhH2IDC)2]·H2O}n (II) were synthesized under hydro(solvo)thermal conditions and structurally characterized by elemental analyses, IR spectroscsopy, and single-crystal X-ray diffraction. Polymer I shows a 2D sheet structure. In polymer II, 1D octagonal channels are connected by the organic ligands to form a 3D architecture. Furthermore, the thermal characteristics of the two polymers and the coordination features of p-BrPhH3IDC were investigated.

Five new Cd(II)-based coordination polymers 1 – 5 with a flexible ligand 1,4-bis(2-methylimidazol-1-ylmethyl)-2,3,5,6-tetramethylbenzene (bmimx) and five dicarboxylate acids (1,2-H 2 BDC = 1,2-benzenedicarboxylic acid, H 2 HMPH = homophthalic acid, 1,3-H 2 BDC = 1,3-benzenedicarboxylic acid, 1,3-H 2 ADA = 1,3-adamantanediacetic acid and H 2 ADI = adipic acid) have been synthesized under hydro(solvo)thermal conditions, namely, [Cd(bmimx) 0.5 (1,2-BDC)] n ( 1 ), {[Cd(bmimx)(HMPH)]·H 2 O} n ( 2 ), {[Cd(bmimx)(1,3-BDC)]·1.5H 2 O} n ( 3 ), {[Cd(bmimx) 0.5 (ADA)]·H 2 O} n ( 4 ) and {[Cd(bmimx)(ADI)]·2H 2 O} n ( 5 ). Structural analysis indicates that all the complexes exhibit 2D layer structures. Complexes 1 and 4 present binodal (3,4)-connected layers with 3,4L83 topology. Complex 2 displays a 4 4 - sql layer with 1D helical chains, while 3 only shows a pleated net with the 4 4 - sql topology. Complex 5 exhibits a sheet structure with hcb topology. The backbones of the dicarboxylate ligands play an important role in determining the structural diversity. Their thermal and luminescent properties are also discussed.

Eight compounds of Co, Ni, and Cu with mellitate ligands display a wide variety of structures with metal–mellitate coordination polymer dimensionality 0–3. Usually mellitate is fully deprotonated (mel6–), but there is one example of Hmel5– and one of H2mel4–. [M3(mel)(OH2)12]·6H2O (M = Co or Ni) are chain polymers with octahedral M, while [Cu7(OH2)19(OH)2(mel)2]·9H2O has a 2D polymer sheet structure with square-based pyramidal Cu. Addition of KOH produces different compounds. Two incorporate K+ in the structures: K+2(OH2)5[{Ni(OH2)5}2(mel)]2–·2H2O contains discrete nickel–mellitate anionic units, and K+2(OH2)6[{Cu(OH2)3}2(mel)]2–·H2O has a copper–mellitate two-dimensional (2D) polymeric anion. For Co the product is [Co(OH2)6]2+[{Co(OH2)4}5(mel)2]2–·4H2O, with a 2D polymeric anion and discrete cations. A gel-supported synthesis leads to [Cu3(OH2)10(Hmel)][Cu2(OH2)6(Hmel)]·7H2O, with two different copper–mellitate polymeric sheets arranged alternately in a stack. [{Cu(OH2)(EtOH)(4,4′-bipy)}2(H2mel)] contain...

Mesoporous Cr2O3 with a high specific surface area of 162 m2 g−1 is prepared by the solution combustion method. The mesoporous Cr2O3 has a sheet structure, which consists of nanoparticles with an average size of 20 nm. As an anode electrode material for rechargeable lithium-ion batteries, the mesoporous Cr2O3 nanoparticles display enhanced electrochemical performance. Stable and reversible capacity of 480 mA h g−1 after 55 cycles is demonstrated. The enhanced electrochemical performance of the Cr2O3 can be attributed to the high surface area and morphological characteristics of mesoporous materials.

In this paper, dmit (dmit = 4,5-disulfanyl-1,3-dithio-2-thionate) and TTF (TTF = tetrathiafulvalene) derivatives, i.e., bedt (bedt = 4,5-bis(ethylsulfanyl)-1,3-dithiole-2-thione), CE-TTF (CE-TTF = 2,3-bis(cyanoethylsulfanyl)-6,7-bis(ethylsulfanyl)-TTF) and tces-TTF (tces-TTF = 2,3,6,7-tetra(cyanoethylsulfanyl)-TTF) were reacted with different silver salts to produce four novel coordination polymer crystals: [Ag(bedt)]ClO4 (1), [Ag2(bedt)2acetone](SbF6)2 (2), [Ag(CE-TTF)](CF3SO3)acetone (3) and [Ag(tces-TTF)2]SbF6 (4). The crystallographic studies indicate that polymer 1 exhibits a 2D sheet structure with a (4,4) network, polymer 2 possesses a 2D lamellar structure with a (6,3) network, polymer 3 exhibits a 2D porous framework with novel meso-helix motifs and complex 4 consists of tetramers with S⋯S interactions, which result in the formation of a 2D supramolecular coordination polymer. Polymer 4 also exhibits semi-conductive behavior with a σ value of 2.29 × 10−5 S cm−1 due to the extensive S⋯S contacts.

The title compound, N-phenylpyridin-4-amine, forms two polymorphs I and II which were obtained from acetonitrile or tetrahydrofuran, respectively. The molecular structures in both polymorphs are similar one another. The pyridyl rings show better conjugation with the lone pairs of the nitrogen atom than phenyl rings. In both polymorphs, the molecules also form a similar sheet structure in which they make zigzag hydrogen bonds. Judged by powder XRD analysis, polymorph I was considered to be the most stable phase at room temperature.

FTIR microspectroscopy was applied for studying macromolecular changes in human serum samples from patients with healthy livers, and those diagnosed with liver cirrhosis or hepatocellular carcinoma (HCC). Our study demonstrated that the serum samples from HCC and cirrhotic patients could readily be discriminated from those from healthy controls based on macromolecular differences related to their lipid and protein structure. Spectral changes appeared to indicate that the secondary structure of protein from HCC sample groups contained a more distinctive β -sheet structure and a lower lipid content compared to samples from the healthy and cirrhosis group. This was correlated with measurements of large decreases in albumin levels in serum from diseased patients. We argue that this technique shows potential as a simple, rapid, inexpensive, and non-subjective methodology for the screening patients suspected of liver disease. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Three new supramolecular coordination polymers, namely [Zn(1,3-BDC)(HL)]n (Polymer 1), [Zn3(1,3,5-BTC)2(HL)2(H2O)2]n (Polymer 2), and [Zn9(5-SO3-1,3-BDC)2(L)8(OH)4]n (Polymer 3), were synthesized under solvothermal conditions, based on 1H-pyrazolo[3,4-b]pyridin-3-amine (HL) along with 1,3-benzenedicarboxylate (1,3-BDC) and its derivatives, such as 1,3,5-benzenetricarboxylate (1,3,5-BTC) and 5-sulfo-1,3-benzenedicarboxylate (5-SO3-1,3-BDC). Polymers 1–3 were characterized by elemental analysis, IR spectroscopy, powder X-ray diffraction (PXRD), and single crystal X-ray diffraction analysis. Polymer 1 exhibited a two-dimensional (2D) 4-connected sql net. The neighboring 2D nets were further linked into a 3D supramolecular network by hydrogen-bonding interactions. Polymer 2 displayed a 3D (4, 4, 4)-connected network, which was further stabilized by R 2 2 (14) and S(9) hydrogen-bonding rings along with π–π interactions. The 2D sheet structure of Polymer 3 was constructed by novel quasi-linear nonanuclear Zn(II) units, which further extended into a 3D supramolecular structure by hydrogen-bonding interactions. The solid-state photoluminescence properties of Polymers 1–3 were also investigated.

In this work, the crystallization and melting behaviors of different polypropylene (PP) materials containing a certain amount of graphene, β-phase nucleating agent (β-NA), and their mixture, respectively, were comparatively investigated. The results showed that graphene exhibited the typical sheet structure in the PP matrix, and the presence of β-NA did not change the dispersion of graphene apparently. Both graphene and β-NA exhibited great nucleating effect for the crystallization of PP. However, the nucleation efficiency of β-NA was much larger than that of graphene. With the simultaneous presence of graphene and β-NA, the crystallization ability of PP matrix was greatly improved, which indicated that there was a synergistic effect between graphene and β-NA in accelerating crystallization of PP matrix. Furthermore, it was proved that the synergistic effect was greatly dependent upon the crystallization conditions. The higher the isothermal crystallization temperature or the bigger the cooling rate, the more apparent the synergistic effect was.

A 2D Strandberg-type phosphomolybdate hybrid [Cu(En)(EnH)]2[P2Mo5O23] · 3H2O (I) (En = ethylenediamine) has been successfully synthesized under hydrothermal conditions and structurally characterized by elemental analyses, IR spectrum, UV spectrum and single-crystal X-ray diffraction. The molecular structural unit of I consists of one Strandberg-type [P2Mo5O23]6− subunit, two [Cu(En)(EnH)]3+ cations and three lattice water molecules. The most remarkable feature of I is that each molecular structural unit is connected with adjacent four same units by four [Cu(En)(EnH)]3+ bridges constructing the 2D organic-inorganic hybrid sheet structure with a 4-connected topology. As far as we know, such 2D hybrid sheet structure constructed from Strandberg-type phosphomolybdate units and copper-organic cation bridges is very rare.

The new ligand N,N′,N″,N″′-tetrakis[3-tert-butyl-5-(4-pyridinyl)salicylidene]-1,2,4,5-benzenetetraamine (bisSalen) containing four pyridyl groups in its periphery was prepared and subsequently used as an organic linker for a Zn–bisSalen MOF. A 2D undulated sheet structure was determined from single-crystal X-ray diffraction studies. The bisSalen ligands bridge two ZnII ions, and one of the pyridyl groups on each side of the bisSalen ligand further coordinates to a bisSalen-coordinated ZnII ion to provide a 2D sheet structure. The undulated 2D sheets are stacked closely together to form a 3D-like structure containing well-defined 1D channels, the orientation of which is perpendicular to the 2D sheets. The geometry of the bisSalen in the MOF is not planar. The remaining uncoordinated pyridyl groups point toward the 1D channels. Because of these openly accessible pyridyl groups in the channels, the Zn–bisSalen MOF is a very active catalyst for transesterifications.

In hot-water molecular dynamics simulation at 370 K, four cellulose IIII crystal models, with different lattice planes and dimensions, exhibited partial crystalline transformations of (1 −1 0) chain sheets, in which hydroxymethyl groups were irreversibly rotated from gt into tg conformations, accompanied by hydrogen-bond exchange from the original O3–O6 to cellulose-I-like O2–O6 bonds. The final hydrogen-bond exchange ratio was about 95 % for some of the crystal models after 50 ns simulation. The corrugated (1 −1 0) chain sheet was converted to a cellulose-I-like flat chain sheet with a slightly right-handed twist. The 3D structures of the three types of isolated chain sheet models were optimized using density functional theory calculations to compare their stabilities without crystal packing forces. The cellulose Iβ (1 0 0) models were more stable than the cellulose IIII (1 −1 0) models. The optimized structure of cellulose IIII (1 0 0) models deviated largely from the initial sheet form. It was proposed to the crystalline transformation from cellulose IIII to Iβ that conversion of the chain sheet structure first take place, followed by sliding of the chain sheet along the fiber axis.

A novel metal-organic framework, MnCl2(BIPS)2•2CH3OH•2H2O (1) were synthesized from MnCl2 and a tetrahedral silicon-cored ligand, Me2Si(p-C6H4-imdazol-1-yl)2 (BIPS) under the slow diffusion method. The structure was determined by single-crystal X-ray diffraction. Complex 1 is a 2D sheet structure constructed from 1D chains with 34-atom metallamacrocycles.

Four new silver(I) coordination polymers (CPs) based on 3-nitrophthalic acid (H2npt), [Ag2(NH3)2(npt)]n (1), [Ag2(NH3)(npt)]n (2), {(NH4)[Ag(npt)·H2O]}n (3) and [Ag4(NH3)4(npt)2·H2O]n (4), have been synthesized and structurally characterized. Compound 1 shows a 1D chain based on a binuclear Ag(I) SBU (secondary building unit). The [Ag(NH3)2] units are bound on the two sides of the 1D chain through the ligand-unsupported argentophilic interactions. Compound 2 is a 2D 44-sql net constructed from npt ligand-bridged centrosymmetric Ag4 rhombus SBUs. Compound 3 exhibits an anionic 2D sheet, in which the infinite chain-like [Ag2(COO)2]n SBUs are observed along the b axis. In compound 4, infinite silver nets are fabricated by ligand-unsupported argentophilic interactions and the npt ligands are anchored on the net to form the 2D sheet structure. Four CPs exhibit unprecedentedly high structural diversity dependent on the solvent and induction agent. In detail, 1, 2 and 3, 4 are mainly controlled by the induction agent, but 1, 3 and 2, 4 are controlled by the solvent systems. The thermal stabilities and photoluminescence behaviours of the compounds were also discussed.

Systemic hypertension is a causative factor in left ventricular hypertrophy (LVH). This study is motivated by the potential to reverse or manage the dysfunction associated with structural remodeling of the myocardium in this pathology. Using diffusion tensor magnetic resonance imaging, we present an analysis of myocardial fiber and laminar sheet orientation in ex vivo hypertrophic (6 SHR) and normal (5 WKY) rat hearts using the covariance of the diffusion tensor. First, an atlas of normal cardiac microstructure was formed using the WKY b0 images. Then, the SHR and WKY b0 hearts were registered to the atlas. The acquired deformation fields were applied to the SHR and WKY heart tensor fields followed by the preservation of principal direction (PPD) reorientation strategy. A mean tensor field was then formed from the registered WKY tensor images. Calculating the covariance of the registered tensor images about this mean for each heart, the hypertrophic myocardium exhibited significantly increased myocardial fiber derangement (p=0.017p=0.017) with a mean dispersion of 38.7 deg, and an increased dispersion of the laminar sheet normal (p=0.030p=0.030) of 54.8 deg compared with 34.8 deg and 51.8 deg, respectively, in the normal hearts. Results demonstrate significantly altered myocardial fiber and laminar sheet structure in rats with hypertensive LVH.

The structure of the title caesium salt with salicylic acid, poly[μ2-aqua-μ4-(salicylato-κ4O1:O1:O1′:O2)caesium], [Cs(C7H5O3)(H2O)]n, represents a second monoclinic polymorph of this compound. The two-dimensional coordination polymeric structure is based on a centrosymmetric dinuclear bridged repeat unit with each irregular CsO6coordination polyhedron comprising a μ2-bridging water molecule and μ4-bridging O-atom donors, three from the carboxyl group and one from the phenolic group of the salicylate ligand. The Cs—O bond range is 3.023 (3)–3.368 (4) Å and the Cs...Cs separation within the dinuclear unit is 4.9265 (6) Å. The polymeric sheet structure lies parallel to (010) with the water molecule and the phenol group involved in intra-polymer O—H...Ocarboxylhydrogen-bonding interactions.

The arsenic(III) and antimony(III) cyanides M(CN)3 (M=As, Sb) have been prepared in quantitative yields from the corresponding trifluorides through fluoride-cyanide exchange with Me3 SiCN in acetonitrile. When the reaction was carried out in the presence of one equivalent of 2,2'-bipyridine, the adducts [M(CN)3 ⋅(2,2'-bipy)] were obtained. The crystal structures of As(CN)3 , [As(CN)3 ⋅(2,2'-bipy)] and [Sb(CN)3 ⋅(2,2'-bipy)] were determined and are surprisingly different. As(CN)3 possesses a polymeric three-dimensional structure, [As(CN)3 ⋅(2,2'-bipy)] exhibits a two-dimensional sheet structure, and [Sb(CN)3 ⋅(2,2'-bipy)] has a chain structure, and none of the structures resembles those found for the corresponding arsenic and antimony triazides.

The viscosity and structure characteristics of FeO-SiO2-V2O3-TiO2-Cr2O3 systems as the main composition of V-slag were investigated with different Cr2O3 and TiO2 contents using the rotating cylinder method and Raman. The results showed that the viscosity was below 3.5 Pa sat 1540 K, and the polymerization degree of the silicate structure was lower than the main monomer structure (Q°) in FeO-SiO2-V2O3 system. With the induction of Cr2O3 to FeO-SiO2-V2O3 system, the viscosity obviously increased ( 3.5 Pa sat 1770 K), with the polymerization degree of molten structures enhanced drastically as formation of a chain structure (Q2 and the O-Cr-O band) and a sheet structure (Q3). With the further induction of TiO2 to the FeO-SiO2-V2O3-Cr2O3 system, the viscosity was 3.5 Pa sat 1630 K, and the polymerization degree became weaker as the forms of discrete Si-O-Ti and Ti-O-Ti decrease to Q3 in a sheet structure.

The dewatering ability and wet sheet structure after pressing was studied using a dynamic wet pressing simulator in combination with electron microscopy and image analysis. Deinked pulp (DIP) that contains 5% ash dewaters more easi ly than thermomechanical pulp (TMP) when pressed with single roll pulse. The in-plane moisture flow ( crushing) in DIP samples started at higher peak pressure and higher solids content compared to TMP samples. The TMP sample showed higher springback after wet pressing compared to DIP samples. When both TMP and DIP samples were designed to have a higher amount of small pores at the dewatering side surface layers, the samples with coarser TMP pulp could achieve similar dryness as DIP samples when pressed with higher nip pressure. In addition, the DIP samples with higher number of small pores in the outermost I 0 11m thick surface layer in the dewatering side resulted in lower dryness after pressing with a single roll pulse. The effect of filler distribution in paper zdirection on dryness and sheet structure after wet pressing using an 8 milliseconds roll pulse was also studied. In this study the distribution of filler does not affect the maximum achievable dryness (4 1 %) after wet pressing when the total amount of filler in the sheets remains constant, 1 3 .5%. In addition, the samples with more filler in the dewatering layer dewater more easily and yield the maximum achievable dryness ( 40%) after wet pressing at lower nip pressure (2 . 5 MPa) when compared to samples made from TMP (3 6% at 4.4 MPa) and DIP pulps (40% at 4 . 9 MPa).

A bistable dynamic coordination polymer [Ni(pca)(bdc)(0.5)(H(2)O)(2)] having a two-dimensional (2D) zigzag sheet structure is synthesized solvothermally. Topological analysis revealed that the frameworks have an hcb type of uninodal net. The compound exhibits guest specific reversible structural transformations accompanying reversible changes in physical properties driven by inherent flexibility and transformability.

The structures are reported of nine closely related tetrahydro-1,4-epoxy-1-benzazepines carrying pendant heterocyclic substituents, namely: 2-exo-(5-nitrofuran-2-yl)-2,3,4,5-tetrahydro-1,4-epoxy-1H-1-benzazepine, C14H12N2O4, (I), 7-fluoro-2-exo-(1-methyl-1H-pyrrol-2-yl)-2,3,4,5-tetrahydro-1,4-epoxy-1H-1-benzazepine, C15H15FN2O, (II), 7-fluoro-2-exo-(5-methylfuran-2-yl)-2,3,4,5-tetrahydro-1,4-epoxy-1H-1-benzazepine, C15H14FNO2, (III), 7-fluoro-2-exo-(3-methylthiophen-2-yl)-2,3,4,5-tetrahydro-1,4-epoxy-1H-1-benzazepine, C15H14FNOS, (IV), 7-fluoro-2-exo-(5-methylthiophen-2-yl)-2,3,4,5-tetrahydro-1,4-epoxy-1H-1-benzazepine, C15H14FNOS, (V), 7-chloro-2-exo-(5-methylfuran-2-yl)-2,3,4,5-tetrahydro-1,4-epoxy-1H-1-benzazepine, C15H14ClNO2, (VI), 2-exo-(5-methylfuran-2-yl)-7-trifluoromethoxy-2,3,4,5-tetrahydro-1,4-epoxy-1H-1-benzazepine, C16H14F3NO3, (VII), 2-exo-(3-methylthiophen-2-yl)-7-trifluoromethoxy-2,3,4,5-tetrahydro-1,4-epoxy-1H-1-benzazepine, C16H14F3NO2S, (VIII), and 2-exo-(5-nitrofuran-2-yl)-7-trifluoromethoxy-2,3,4,5-tetrahydro-1,4-epoxy-1H-1-benzazepine, C15H11F3N2O5, (IX). All nine compounds crystallize in centrosymmetric space groups as racemic mixtures with configuration (2RS,4SR). There are no direction-specific interactions between the molecules in (V). The molecules in (III), (IV), (VI) and (VII) are linked into simple chains, by means of a single C—H...O hydrogen bond in each of (III), (VI) and (VII), and by means of a single C—H...π(arene) hydrogen bond in (IV), while the molecules in (VIII) are linked into a chain of rings. In each of (I) and (II), a combination of one C—H...O hydrogen bond and one C—H...π(arene) hydrogen bond links the molecules into sheets, albeit of completely different construction in the two compounds. In (IX), the sheet structure is built from a combination of four independent C—H...O hydrogen bonds and one C—H...π(arene) hydrogen bond. Comparisons are made with some related compounds.

In this paper, tubular structure has been obtained by self-assembly of cholesterol derivative via sol–gel process. The tube structure and the formation mechanism have been studied and certified by scanning electron microscopy, infrared, ultraviolet-visible spectroscopy (UV–vis) and x-ray diffraction (XRD) data. It is predicated that the tube has been formed by the curl of sheet structure, and the aggregates are composed of two molecules of 1 with H aggregate in laminar structure at micro level.

The title metal-organic framework, [Cd(3)(C(12)H(9)O(6))(2)(C(10)H(8)N(2))(2)](n), has been synthesized by a solvothermal reaction. The Cd(II) ions are located in CdO(4)N(2) and CdO(6) six-coordinated environments, with the latter Cd(II) ion lying on an inversion centre. The 2,4,6-trimethylbenzene-1,3,5-tricarboxylate ligand (TMBTC) connects the Cd(II) ions to form a two-dimensional sheet incorporating hourglass-like [Cd(3)(COO)(6)] secondary building units (SBUs). Topologically, taking the TMBTC ligand and the [Cd(3)(COO)(6)] SBU as 3- and 6-connected nodes, respectively, the overall two-dimensional sheet can be simplified to a rare (3,6)-connected 2-nodal kgd (Kagomé dual) net with a short Schläfli vertex notation of {4(3)}(2){4(6).6(6).8(3)}, which further stacks into a three-dimensional supramolecular framework through π-π stacking interactions.

The title compound, C28H20N2O2, forms two conformational polymorphs, (I) and (II), where the mol­ecular structures are similar except for the orientation of the two hy­droxy groups. In (I), which was obtained by slow evaporation from chloro­form, the two hy­droxy groups have an anti conformation. The mol­ecules form a sheet structure within the ac plane, where the hy­droxy groups form zigzag hydrogen bonds. In (II), which was obtained by slow evaporation from acetonitrile, the two hy­droxy groups have a syn conformation. The mol­ecules form a double-sheet structure within the ab plane, where the hy­droxy groups form 4-helix hydrogen bonds.

Occasional references to the relative tectonic instability of the Australian continent have been published over the last hundred years or so. Youthful tectonic forms were described from various parts of the continent throughout that period. Despite this, it was repeatedly claimed that the shield lands in particular were tectonically stable, and as recently as this century reference has been made to a concept embracing a tectonically inert continent. However, some 60 years ago, the accumulated evidence convinced E.S. Hills that in Australia all land surfaces, including the shield lands, and even recent alluvial plains, were tectonically disturbed. This conclusion was reinforced by analyses of seismicity and faulting; by regional geological mapping that revealed widely distributed tectonic forms and especially fault-related features, many of them of neotectonic age; by technological advances that allow faulting episodes to be closely dated; by the recognition of underprinting; and by the realization that many minor forms, previously unrecognized or attributed to other mechanisms or processes, are associated with crustal stress and are of tectonic origin. Thus, while Australia is a relatively stable continent, it is subject to widespread small-magnitude earth movements. Ironically, in view of earlier thinking, neotectonic forms may be better developed and preserved on the shields than elsewhere.

Based on elastic mechanics, this article deduced the theoretical value of the maximum stress and maximum deflection of sheet structure which was applied on point supported glass curtain wall structure, and figure out the stress and deflection values by calculation example. After that by simulating the structure with the finite element software ANSYS we drew the cloud atlas of stress and deflection values which we analyzed and compared with the theoretical values. Finally we can work out the error between the theoretical values and simulate value and analysis it.

Three new complexes with embellished dicarboxylate, [ (2,2′-bpy)2(H2O)2] (1), [ (2,2′-bpy)2(H2O)2] (2), and [NiIIL(4,4′-bpy)(H2O)] (3) (H2L = 4,6-dibenzoylisophthalic acid, 2,2′-bpy = 2,2′-bipyridine, 4,4′-bpy = 4,4′-bipyridine), were synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectra and X-ray diffraction. Complexes 1 and 2 are binuclear structures with 16-membered rings. Complex 3 shows a 2-D sheet structure. Intermolecular O–H ··· O interactions extend 1 and 2 into 1-D chains. Luminescence properties have been investigated for 1 and 2.

The product from the reaction between Cd(NO3)2·4H2O and 1,3,5-benzenetricarboxylic acid (H3btc) in DMF at 95 °C depends on the reaction time, with [Cd(Hbtc)(H2O)2] 1 and [Cd(Hbtc)(DMF)2] 2 isolated after heating for 10 min, the latter after standing the solution for 1–2 weeks at room temperature. [Cd3(btc)2(H2O)9]·4H2O 3 was isolated after heating for 1 h, whereas [Cd12(btc)8(DMF)14(OH2)2]·1.5DMF 4 was isolated after heating for 2 days. Compounds 1 and 3 have been previously reported, whereas 2 and 4 are both new. Compound 2 adopts a two-dimensional sheet structure, with the coordinated DMF ligands projecting from both sides of the sheets, whereas 4 has a complex three-dimensional structure related to the fsc net. When the reaction was repeated in the presence of pyrazine (pyz), the product [Cd(Hbtc)(pyz)(DMF)]·DMF 5 was isolated as a minor compound. Compound 5 has a two-dimensional structure, with Cd-Hbtc zig-zag chains linked into sheets through the pyrazine ligands.

Islet amyloid polypeptide (IAPP or Amylin) is a 37-residue, C-terminally amidated pancreatic hormone, cosecreted with insulin that forms islet amyloid in type 2 diabetes. Islet amyloid formation is complex and characterizing preamyloid oligomers is an important topic because oligomeric intermediates are postulated to be the most toxic species produced during fibril formation. A range of competing models for early oligomers have been proposed. The role of the amidated C-terminus in amyloid formation by IAPP and in stabilizing oligomers is not known. Studies with unamidated IAPP have provided evidence for formation of an antiparallel dimer at pH 5.5, stabilized by stacking of His-18 and Tyr-37, but it is not known if this interaction is formed in the physiological form of the peptide. Analysis of a set of variants with a free and with an amidated C-terminus shows that disrupting the putative His-Tyr interaction accelerates amyloid formation, indicating that it is not essential. Amidation to generate the physiologically relevant form of IAPP accelerates amyloid formation, demonstrating that the advantages conferred by C-terminal amidation outweigh increased amyloidogenicity. The analysis of this variant argues that IAPP is not under strong evolutionary pressure to reduce amyloidogenicity. Analysis of an H18Q mutant of IAPP shows that the charge state of the N-terminus is an important factor controlling the rate of amyloid formation, even though the N-terminal region of IAPP is believed to be flexible in the amyloid fibers.

Melanin remains one of the most enigmatic of pigments. It occurs in a variety of forms, but is perhaps best known for its role in providing ultra-violet protection of skin as brown/black eumelanin and red/yellow pheomelanin. Despite decades of research many questions remain about the structure, spectroscopy and biology of both forms. For example, their unusually broad optical absorption spectra have attracted different explanations, no protomolecule has ever been identified and pheomelanin has been implicated in melanoma, the most virulent form of skin cancer. Knowing more about the structure and spectroscopy of melanin is of paramount importance, not only in biology and medicine, but also in the design of biomimetic functional devices. There is general consistency across a variety of techniques that eumelanin’s building blocks arrange in π - stacked sheets analogous to graphite. By comparison pheomelanin has been the neglected sibling and here we present evidence from fluorescence spectroscopy for pheomelanin also displaying sheet-like behavior. As pheomelanin is synthesized the temporal response of the fluorescence intensity of the sheet-sensing probe thioflavin T (ThT) follows a similar sigmoidal increase as previously reported for eumelanin. Consistent with such intercalation fluorescence decay measurements reveal evidence for close coupling between melanin and ThT excited states.

Superplastic forming of a three-sheet structure is considered. The focus is on overcoming the main disadvantages of the process of manufacturing of such structures by means of the SPF/DB technique including high temperatures of treatment and the formation of folds on the outer surface of the article manufactured. The application of ultrafine-grained sheets of titanium alloy Ti-6Al-4V has been analyzed in order to avoid these disadvantages. Various combinations of the use of ultrafine-grained and microcrystalline sheets as skin and core sheets are considered by means of the finite element analysis. The standard power law of superplasticity is used for analysis with material constants determined from technological experiments. The conclusion is made that the most attractive way appears to be the usage of ultafine-grained material for the core sheet and microcrystalline material for the skin sheets.

A new 2D cadmium(II) thiocyanato complex, [CdL(NCS)2]n (L = 2-acetylpyridine), has been prepared and characterized by IR spectra and single crystal X-ray diffraction. The Cd atom in the complex is coordinated by one N and one acetyl O atoms of 2-acetylpyridine, and two N atoms and two S atoms from four different end-to-end (μ1,3-) bridging thiocyanate groups. The thiocyanate groups link the [CdL] units to form a 2D sheet structure. The complex shows strong cytotoxic property to carcinoma cells.

In this paper, the technology of self-piercing riveting (SPR) with half-hollow rivets was investigated using experiments and numerical simulations with 6063 aluminum alloy sheet. The failure mechanism of SPR aluminum alloy sheet was indicated with the shear model and tear model, which could accurately simulate the sheet structure. Based on the simulation results with finite element method (FEA), the effect of die geometry on static mechanical characteristics, including punch load, failure load and failure displacement, was analyzed. It was discovered that the die pip height and sheet thickness should be designed synthetically for optimal tensile behavior.

We report direct numerical simulations of swirling liquid atomization to understand the physical mechanism underlying the sheet breakup of a non-turbulent liquid swirling jet which lacks in-depth investigation. The volume-of-fluid (VOF) method coupled with adapted mesh refinement (AMR) technique in GERRIS code is employed in the present simulation. The mechanisms of sheet, ligament and droplet formation are investigated. It is observed that the olive-shape sheet structure is similar to the experimental result qualitatively. The numerical results show that surface tension, pressure difference and swirling effect contribute to the contraction and extension of liquid sheet. The ligament formation is partially at the sheet rim or attributed to the extension of liquid hole. Especially, the movement of hairpin vortex exerts by an anti-radial direction force to the sheet surface and leads to the sheet thinness. In addition, droplet formation is attributed to breakup of ligament and central sheet.

In this paper, an innovative double rib sheet structure is proposed, which can replace the traditional rigid hinge joint with the surface contact. On the one hand, the variable camber wing structural design not only can improve the capacity to sustain more load but also will not increase the overall weight of the wing. On the other hand, it is a simple mechanical structure design to achieve the total wing camber change. Then the numerical simulation results show that the maximum stress at the connect of the wing rib is 88.2MPa, and the double ribs sheet engineering design meet the structural strength requirements. In addition, to make a fair comparison, the parameters of variable camber are fully referenced to the Talon Unmanned Aerial Vehicle (UAV). The results reveal that the total variable camber wing can further enhance aircraft flight efficiency by 29.4%. The design of the whole variable camber wing structure proposed in this paper has high engineering value and feasibility.

As proteins aggregate to form amyloid fibers, their secondary structure changes from its native form to cross-beta-sheet. Whether this conformational change is essential for fiber formation remains unknown. Evidence from atomic force microscopy and transmission electron microscopy suggests that aggregation occurs in two stages. Initially, protein monomers aggregate into colloidal spheres; however, they stop growing after reaching a uniform diameter. The spheres then join together to form linear chains which evolve into mature fibers. In this paper, we apply, for the first time, the DLVO theory, formulated by Derjaguin, Landau, Verwey and Overbeek for the quantitative analysis of colloidal interactions, to elucidate the two stages of fiber formation. We find that, as like-charged protein molecules aggregate, the total charge of the colloidal sphere increases until it repels additional monomers from coming close enough to bind, limiting the size of the colloidal particle. Energy analysis and X-ray diffraction data suggest that aggregation of multiple protein monomers onto the growing colloid drives their misfolding into hairpin loops. These loops stack together to form a U-shaped trough which initially adopts a cross-alpha-sheet structure with a strong dipole moment. Driven by charge-dipole interactions, the colloidal spheres aggregate into a linear chain. The peptide strands are oriented perpendicular to the direction of the dipole of each sphere and, therefore, are also perpendicular to the axis of the linear chain as it forms and evolves into the mature fiber. The cross alpha-sheet then evolves into the thermodynamically more stable cross beta-sheet.

New oxoverdazyl (Vz·)-substituted dihydrophenazine radical cations (DPP +) MCl 4 - (M = Ga, Fe) salts were prepared. The molecular and packing structures, the intramolecular exchange interactions, and the magnetic properties were investigated. The organic part (VzDPP +) showed a sizable intramolecular ferromagnetic interaction of J/kB ⩾ +250 K ( H = - 2 J S Vz · S DPP · + ) between Vz and DPP +, giving S = 1 state at room temperature. Both compounds had very similar molecular and packing structures and there were several intermolecular short contacts between the magnetically important atoms. A 2D type sheet structure was constructed through the contacts between VzDPP + and MCl 4 - moieties in the b–c∗ plane and a linear ladder chain structure was observed in the a∗-direction through the contacts between VzDPP + moieties. Thus, the overall intermolecular contacts extend in a 3D manner. The χpT value gradually decreased by lowering the temperature, indicating antiferromagnetic interactions in both salts. From the temperature dependence of χpT with consideration of the crystal packing structures, the antiferromagnetic interaction between the VzDPP + spins within the ladder chain was estimated to be in the order of −30 K for VzDPP + · GaCl 4 - . A similar antiferromagnetic interaction between the VzDPP + spins within the ladder chain and a slightly weaker antiferromagnetic interaction between the Fe(III) spins through the ladder chain were observed for VzDPP + · FeCl 4 - .

Hydrothermal synthesis in the M/Mo/O (M=Co,Ni) system was investigated. Novel transition metal tetramolybdate dihydrates MMo4O13·2H2O (M=Co,Ni), having an interesting pillared layer structure, were found. The molybdates crystallize in the triclinic system with space group P−1, Z=1 with unit cell parameters of a=5.525(3) A, b=7.058(4) A, c=7.551(5) A, α=90.019(10)°, β=105.230(10)°, γ=90.286(10)° for CoMo4O13·2H2O, and a=5.508(2) A, b=7.017(3) A, c=7.533(3) A, α=90.152(6)°, β=105.216(6)°, γ=90.161(6)° for NiMo4O13·2H2O The structure is composed of two-dimensional molybdenum-oxide (2D Mo-O) sheets pillared with CoO6 octahedra. The 2D Mo-O sheet is made up of infinite straight ribbons built up by corner-sharing of four molybdenum octahedra (two MoO6 and two MoO5OH2) sharing edges. These infinite ribbons are similar to the straight ones in triclinic-K2Mo4O13 having 1D chain structure, but are linked one after another by corner-sharing to form a 2D sheet structure, like the twisted ribbons in BaMo4O13·2H2O (or in orthorhombic-K2Mo4O13) are.

(Chemical Equation Presented) A twist of fate: Parallel-turn linkers comprising an amino acid derived alcohol conjoined with an aromatic amide through a flexible linkage adopt reverseturn conformations. Cyclopropane tetra-and hexapeptide analogues form a C-H⋯O hydrogen-bond-stabilized parallel-sheet conformation (see scheme). NMR studies confirm the presence of hydrogen bonds in these structures. © 2008 Wiley-VCH Verlag GmbH and Co. KGaA.

This paper is aimed at research on brazing technological parameters of thin-wall capillary tube–sheet joints with vacuum scanning electron beam (VSEB) heating system, which is a full automatic closed-loop control system and can be used to program and generate any expected scanning tracks by computer virtual technique. As the new method is adopted, general brazing defects such as erosion, burning through, jam will be prevented effectively. Therefore various thin-wall tube–sheet structures can be brazed successfully, and welding quality and brazing productivity have been raised immensely.