Capping Units Research Articles

ADHD “Symptomatic contamination” in dual pathology (II): Specific analysis of the “Sym_Con” sample

IntroductionThe general data of this sample were presented in “ADHD symptomatic contamination in a Dual Pathology (I): General Analysis of the Sym_Con Sample”. We evaluated the presence of symptomatic contamination by ADHD in a SUD group compared with a group of non-consumers adults (parents of children treated in a CAP unit).Objective and aimsDescribe more specifically the peculiarities of the sample Sym_Con according to the type of substance consumption (Alcohol [n = 65], Cocaine [n = 48], Cannabis [n = 49] assessing the presence of ADHD symptomatic contamination.MethodsWe use differents Visual Analogical Scales plus the WURS, BDI, and Exploratory Lists of symptoms of ADHD.ResultsAs can be seen in Fig. 1 and 2, the subgroup of Alcohol has a poorer “scalar” status with worse general state, more sadness and anxiety, being the subgroup of cocaine the most “suspicious”. The presence of ADHD-symptomatic contamination is more noticeable in the Cannabis subgroup.ConclusionsADHD symptomatic contamination in our Sym_Con sample is frequent, being the cannabis subgroup the more contaminated one. More studies that corroborate the results obtained in this sample are required.Disclosure of interestThe authors have not supplied their declaration of competing interest.

An improved capping unit for stabilizing the ends of associated β-strands

Understanding protein beta structures has been hindered by the challenge of designing small, well-folded β-sheet systems. A β-capping motif was previously designed to help solve this problem, but not without limitations, as the termini of this β-cap were not fully available for chain extension. Combining Coulombic side chain attractions with a Trp/Trp edge-to-face interaction we produced a new capping motif that provided greater β-sheet stability. This stability was maintained even in systems lacking a turn locus with a high propensity for chain direction reversal. The Coulombic cap was shown to improve β-sheet stability in a number of difficult systems, hence providing an additional tool for protein structure and folding studies.

Light-induced and redox-triggered uptake and release of substrates to and from mesoporous SiO2 nanoparticles.

The photonic- and redox-triggered cyclic uptake and release of organic substrates in functionalized mesoporous SiO2 nanoparticles (NPs) is demonstrated. The mesoporous SiO2 NPs are functionalized with nitrospiropyran photoisomerizable units. Rhodamine B is encapsulated in the channels of the SiO2 NPs and trapped by the hydrophobic nitrospiropyran capping units. Photoisomerization of the capping units to the protonated nitromerocyanine groups opens the channels and releases the encapsulated dye. Similarly, modification of the SiO2 channels by chloronaphthoquinone units traps eosin Y in the channels, by means of donor-acceptor interactions. The reduction of the quinone units to the chloronaphth hydroquinone donor groups opens the channels and releases the encapsulated substrate. The novelty of the study rests on the demonstration of the reversible and cyclic photostimulated or redox-activated uptake and release of substrates from the mesoporous SiO2 NPs.

Structure–Photoluminescence Quenching Relationships of Iridium(III)–Tris(phenylpyridine) Complexes (Eur. J. Inorg. Chem. 7/2012)

AbstractThe cover picture shows two “gladiator” compounds illustrating the Structure‐Photoluminescence Quenching Relationship (SPQR) observed in hemicaged Ir(III)–tris(2‐phenylpyridine) complexes bearing a capping unit (“gshield”), either on the pyridine or on the phenyl side. The presence of a capping unit on the pyridine side induces a dramatic 40 % decrease in oxygen quenching of the luminescence with respect to the uncapped complex, as a consequence of the shielding of the LUMO; conversely, shielding of the phenyl rings, where the HOMO is partially localized, does not induce any change in the degree of oxygen quenching. The Roman Empire initialism SPQR and the “hemicaged” laurel further symbolize this study, with the emperor's thumps up and down indicating the winning and losing gladiator, respectively. Details of the synthesis and the structural, photophysical, theoretical, and electrochemical characterization are discussed in the article by L. De Cola, A. H. Velders et al. on p. 1025 ff. magnified image

Structure–Photoluminescence Quenching Relationships of Iridium(III)–Tris(phenylpyridine) Complexes

AbstractThe synthesis, structural, photophysical, theoretical, and electrochemical characterization of four tris(2‐phenylpyridine)‐based IrIII complexes are reported. The complexes were functionalized on the pyridine or on the phenyl rings with amide moieties substituted with a tris(ethyl)amine or ethyl groups, thereby yielding a family of compounds with hemicaged or open (without a capping unit but with similar functional groups on the ligand) structure. Within the context of the parent tris(2‐phenylpyridine) and the full‐cage iridium(III) complexes, structure–photoluminescence quenching relationships (SPQR) of the four complexes have been investigated. Luminescence quenching by oxygen has been studied with Stern–Volmer plots and through evaluation of the thermodynamic parameters involved in the quenching process. Density functional theory (DFT) and time‐dependent DFT (TD‐DFT) calculations have been performed on the complexes to gain insights into structural and electronicfeatures and the nature of the excited states involved in the electronic absorption processes. Interestingly, shielding by the capping unit of moieties in which the LUMO orbital is mostly localized (on the pyridines) results in a dramatic 40 % decrease in oxygen quenching. Conversely, shielding ofmoieties in which the HOMO orbital is partially localized (on the phenyl rings) does not induce any change in the oxygen quenching degree. In both sets of compounds, the thermodynamic feasibility of oxygen quenching is the same for the hemicaged and open compounds, thus giving evidence of the structural origin of such quenching decrease. The SPQRopens up new routes to the design of tailored, more or less sensitive to oxygen, luminescent iridium complexes (e.g., for use as biolabels).

Integrating or disintegrating effects of customised care: the role of professions beyond NPM

This paper aims to describe the integrating and disintegrating effects of professional actions in customised care. Using a qualitative case study, the authors examine the work practices and cultures of three Swedish child and adolescent psychiatric care units (CAP) charged with providing customised care in collaboration with other organisations. The authors conducted 62 interviews, made 11 half-day observations, and shadowed employees for two days. The social embeddedness of action is crucial to understanding the professions' integrating/disintegrating activities. In the internal social context of CAP, the professions adapt to productivity-enhancing new public management (NPM) principles, resulting in integrating effects between the different professions and administrative management in the CAP units. However, CAP exercises professional dominance over the cooperating organisations. Thus, in the external social context, CAP's resistance to customised care principles exacerbates the disintegration problems among the different organisations. The study concludes that, contrary to findings in many other studies, neither the professional logic nor NPM/customised care reforms determine the actions of professionals. In this case, the institutionalisation of some NPM methods blocks the adoption of customised care practices. Contrary to the widely accepted idea that resource restriction is a main source of conflict between management and the professions, the professions accept and adapt to resource restrictions, even at the expense of de-emphasising the practices of customised care. Thus, since professionals choose different operational strategies depending on the social context, the success of a normative reform measure may depend in part on its social context.

Yttrium(III)-Containing Tungstoantimonate(III) Stabilized by Tetrahedral WO42− Capping Unit, [{Y(α-SbW9O31(OH)2)(CH3COO)(H2O)}3(WO4)]17−

The yttrium(III)-containing tungstoantimonate(III) [{Y(α-SbW(9)O(31)(OH)(2))(CH(3)COO)(H(2)O)}(3)(WO(4))](17-) (1) has been synthesized in a simple one-pot reaction of Y(3+) ions with [α-SbW(9)O(33)](9-) and WO(4)(2-) in a 3:3:1 molar ratio in 1 M LiOAc/AcOH buffer at pH 5.3. Polyanion 1 is composed of three (α-SbW(9)O(33)) units linked by three Y(3+) ions and a capping, tetrahedral WO(4)(2-) capping unit, resulting in an assembly with C(3v) symmetry. The hydrated ammonium-sodium salt of 1 was investigated in the solid state by single-crystal XRD, FT-IR spectroscopy, thermogravimetric and elemental analyses, and in solution by multinuclear NMR spectroscopy.

Stratigraphy of hydrated sulfates in the sedimentary deposits of Aram Chaos, Mars

Sedimentary deposits within the 280 km wide crater containing Aram Chaos (∼3°N, 339°E) have been differentially eroded by wind to expose a stratigraphic column 900–1000 m thick that unconformably overlies the chaos bedrock. A detailed stratigraphic and mineralogical description of the deposits is presented based on data from the Mars Reconnaissance Orbiter Compact Reconnaissance Imaging Spectrometer for Mars, Context Imager, and High Resolution Imaging Science Experiment. Two sedimentary units overlie the basement chaos material representing the original plains fill in Aram Crater: the first and oldest is composed of (1) a 50–75 m thick dark‐toned basal unit containing ferric hydroxysulfate intercalated with monohydrated‐sulfate‐bearing materials, (2) a 75–100 m thick light‐toned unit with monohydrated sulfates, and (3) a 175–350 m thick light‐toned resistant capping unit with nanophase ferric oxides and monohydrated sulfates. After a period of wind erosion, these deposits were partially and unconformably covered by the second sedimentary unit, a 75–100 m thick, discontinuous dark‐toned unit containing crystalline hematite and polyhydrated sulfate material. These sedimentary deposits were formed by evaporite deposition during at least two distinct rising groundwater episodes fed by regional‐scale recharge. Later groundwater event(s) formed the polyhydrated materials, indicating that environmental conditions changed to a higher water‐to‐rock ratio. Wind has continued to shape the landscape after the last wetting event to produce the features and exposures observed.

Characterisation of South African Equity Unit Trusts Using The Active Share Measure as a Performance Indicator

This study investigates the relationship between the active share, tracking error and investment performance of South African general equity and large cap unit trusts for the period 2003 to 2007. Active share reflects the amount of deviation of a unit trust’s equity holdings from a benchmark. The development of active share over time amongst unit trusts is investigated, as well as the relationship between active share, tracking error, fund size, number of equities in a unit trust and systematic risk as measured by beta. It was found that outperformance, as measured by Jensen’s α and the Omega ratio, was statistically significant for unit trusts in the highest active share quintiles. The relationship between tracking error quintiles and performance was less consistent. A slight increase with time in the active share value was observed — possibly as a result of a move away from resources and large cap shares, which are concentrated in the JSE indices. High active share was found to be associated with a larger number of active positions, a beta against the benchmark of less than one and low numbers of stocks. No relationship between active share and size was found.

Bis{tris[3-(2-pyridyl)-1H-pyrazole]iron(II)} tetradecamolybdo(V,VI)silicate

The asymmetric unit of the title compound, [Fe(C8H7N3)3]2[SiMo14O44], consists of a complex [Fe(C8H7N3)3]2+ cation and half of a derivative of an α-Keggin-type anion, [SiMo14O44]4−. In the mixed-valent MoV/VI anion, the α-Keggin type core is capped on two oppositely disposed tetra­gonal faces by additional (MoO2) units. The [SiMo14O44]4− anion shows disorder. Two O atoms of the central SiO4 group ( symmetry) are equally disordered about an inversion centre. Moreover, two of the outer bridging O atoms and the O atoms of the capping (MoO2) unit are likewise disordered. The Fe2+ cation is surrounded in a slightly distorted octa­hedral coordination by six N atoms from three 3-(2-pyrid­yl)-1H-pyrazole ligands. N—H⋯O hydrogen bonding between the cations and anions leads to a consolidation of the structure.

P4 capped amides and lactams as HCV NS3 protease inhibitors with improved potency and DMPK profile

SAR studies on the extension of P3 unit of Boceprevir ( 1, SCH 503034) with amides and lactams and their synthesis is described. Extensive SAR studies resulted in the identification of 36 bearing 4, 4-dimethyl lactam as the new P4 cap unit with improved potency ( K i ∗ = 15 nM , EC 90 = 70 nM) and pharmacokinetic properties (Rat AUC (PO) = 3.52 μM h) compared to 1.

Formation of VV Lacunary Polyoxovanadates and Interconversion Reactions of Dodecavanadate Species

AbstractOxidation reactions of the reduced decavanadate [VIV2VV8O26]4– (1) with halide guest anions were investigated for the synthesis of VV host molecules. The reaction with Cl– afforded a new dodecavanadate, [HVV12O32(Cl)]4– (3), which incorporated the guest chloride anion. The polyoxovanadate framework of 3 is different from the bowl‐shaped dodecavanadate [VV12O32(CH3CN)]4– (2). The structure of 3 is regarded as a trilacunary counterpart of the pentadecavanadate [VV9VIV6O36Cl]4–. Employment of an F– template yielded the layered polyoxovanadate [HVV11O29F2]4– (4). The framework of 4 is a monolacunary structure of the fluoride‐incorporated dodecavanadate [H6VV2VIV10O30F2]6–, in which one of the VO groups at the belt position is removed. The three vanadium atoms in the capping units are connected by μ3‐F bridges. Reaction with Br– provided [HVV12O32(Br)]4– (5) with minor formation of [H3VV10O28]3–. Interconversion reactions between 2, 3, and 4 proceeded as follows: the reaction of 2 with Cl– prompted an isomerization reaction of the bowl‐type framework, affording 3; the reaction of 3 with F– gave 4; the reaction of 4 with CH3CN reproduced acetonitrile‐incorporated 2. Complexes 3 and 4 were characterized by X‐ray analysis. Polyoxovanadates 3 and 4, with the highest oxidation cores, exhibited distinct signals in the 51V NMR spectra, corresponding to lacunary polyoxovanadate geometries. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Characterization of phyllosilicates observed in the central Mawrth Vallis region, Mars, their potential formational processes, and implications for past climate

Mawrth Vallis contains one of the largest exposures of phyllosilicates on Mars. Nontronite, montmorillonite, kaolinite, and hydrated silica have been identified throughout the region using data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM). In addition, saponite has been identified in one observation within a crater. These individual minerals are identified and distinguished by features at 1.38–1.42, ∼1.91, and 2.17–2.41μm. There are two main phyllosilicate units in the Mawrth Vallis region. The lowermost unit is nontronite bearing, unconformably overlain by an Al‐phyllosilicate unit containing montmorillonite plus hydrated silica, with a thin layer of kaolinite plus hydrated silica at the top of the unit. These two units are draped by a spectrally unremarkable capping unit. Smectites generally form in neutral to alkaline environments, while kaolinite and hydrated silica typically form in slightly acidic conditions; thus, the observed phyllosilicates may reflect a change in aqueous chemistry. Spectra retrieved near the boundary between the nontronite and Al‐phyllosilicate units exhibit a strong positive slope from 1 to 2μm, likely from a ferrous component within the rock. This ferrous component indicates either rapid deposition in an oxidizing environment or reducing conditions. Formation of each of the phyllosilicate minerals identified requires liquid water, thus indicating a regional wet period in the Noachian when these units formed. The two main phyllosilicate units may be extensive layers of altered volcanic ash. Other potential formational processes include sediment deposition into a marine or lacustrine basin or pedogenesis.

Wire-like diruthenium σ-alkynyl compounds and charge mobility therein

Described in this short review is the chemistry of wire-like diruthenium σ-alkynyl species, which are promising building blocks for organometallic molecular wires. Two series of carbon-rich compounds have been studied: (a) polyyn-diyls with diruthenium capping units, and (b) bi-ferrocenes with a diruthenium alkynyl bridge. Investigations of both the charge transfer process across the polyyn-diyls and the role of diruthenium cores in enhancing charge mobility are achieved through X-ray structure determination, spectroscopic, voltammetric and spectroelectrochemical measurements.

The origin of conical mounds at the mouth of Chasma Boreale

One‐hundred and six isolated conical mound landforms were identified proximal to the north polar cap of Mars at the mouth of Chasma Boreale. Five unique morphologies were identified including moderately sloped (4°–6°) cratered mound forms including two mounds of Abalos Colles, flat‐topped moderately sloped (4°–6°) polygonal mound forms, steeper (6–13°) conical mound forms, subdued mound forms with low‐angle slopes (0.5–3°), and small (<2 km diameter) clustered conical forms with low‐ to moderate‐angle (1–5°) flank slopes. From first‐order relationships between flank slope and the volcano productivity index (volume/diameter ratio), 16 mounds were found to be morphologically similar to terrestrial low‐angle basaltic shield volcanoes. Thirteen mounds exhibit summit craters that range in depth (d) to diameter (D) ratio from 1:9 to 1:320. The circularity and d/D ratios of mound summit craters are consistent with highly modified northern plains impact craters. Image analysis of shield‐like mounds reveals morphologic characteristics inconsistent with pristine volcanic landforms for most features. Horizontal flank layering (10–100 m thick), polygonal map‐view morphology, topographic relationships, and spatial association with retreating polar scarps suggest that mound forms at the mouth of Chasma Boreale represent remnants of a once thicker, more continuous sequence of near‐polar layered material. Evidence for northward scarp retreat is visible along Rupes Tenuis, a sinuous scarp located west of Chasma Boreale. Along this scarp, a single ∼100‐m‐thick resistant cap unit (part of the Early Amazonian age Rupes Tenuis unit) is being undermined by aeolian erosion, solar ablation, and mass wasting. Remnants of the cap unit rest along the scarp margin and in places form small conical mound clusters at the base of the scarp. Fracture controlled retreat of the scarp is visible along the eastern portion of Rupes Tenuis and along the Escorial crater remnant mesa where small tongue‐like promontories have been sculpted into the cap unit. Isolation of these irregularities by scarp retreat has formed several volcanic‐like scarp and mesa proximal mounds. Mound forms located closest to the retreating Rupes Tenuis scarp above 78°N were found to be the steepest and tallest mound landforms in the region. Mounds located distal to Rupes Tenuis were found to be broad and subdued. This observation is consistent with long‐term retreat of a once more extensive Rupes Tenuis scarp and long‐term modification of isolated conical remnants.

Use of Molecular‐Dynamics Simulation for Optimizing Protein Stability: Consensus‐Designed Ankyrin Repeat Proteins

AbstractIn earlier work, two highly homologous (87% sequence identity) ankyrin repeat (AR) proteins, E3_5 and E3_19, were studied using molecular‐dynamics (MD) simulation. Their stabilities were compared, and it was found that the C‐terminal capping unit is unstable in the protein E3_19, in agreement with CD experiments. The different stabilities of these two very similar proteins could be explained by the different charge distributions among the AR units of the two proteins. Here, another AR protein, N3C, with yet another charge distribution has been simulated using MD, and its stability was analyzed. In agreement with the experimental data, the structure of N3C was found to be less stable than that of E3_5, but, in contrast to E3_19, secondary structure was only slightly lost, while structurally N3C is closer to E3_19 than to E3_5. The results suggest that a homogeneous charge distribution over the repeat units does enhance the stability of design AR proteins in aqueous solution, which, however, may be modulated by the bulkiness of amino‐acid side chains involved in the mutations.

Importance of aeolian processes in the origin of the north polar chasmata, Mars

A detailed examination of the location and orientation of sand dunes and other aeolian features within the north polar chasmata indicates that steep scarps strongly influence the direction and intensity of prevailing winds. These steep scarps are present at the heads and along the margins of the north polar chasmata. Topographic profiles of the arcuate head scarps and equator-facing wall of Chasma Boreale reveal unusually steep polar slopes ranging from ∼6°–30°. The relatively steep-sloped (∼8°), sinuous scarp at the head of two smaller chasmata, located west of Chasma Boreale, exhibits an obvious resistant cap-forming unit. Scarp retreat is occurring in places where the cap unit is actively being undercut by descending slope winds. Low-albedo surfaces lacking sand dunes or dust mantles are present at the base of the polar scarps. A ∼100–300 m deep moat, located at the base of the scarps, corresponds with these surfaces and indicates an area of active aeolian scour from descending katabatic winds. Small local dust storms observed along the equator-facing wall of Chasma Boreale imply that slope wind velocities in Chasma Boreale are sufficient to mobilize dust and sand-sized particles in the Polar Layered Deposits (PLD). Two amphitheater forms, located above the cap-forming unit of the sinuous scarp and west of Chasma Boreale, may represent an early stage of polar scarp and chasma formation. These two forms are developing within a younger section of polar layered materials. The unusually steep scarps associated with the polar chasmata have developed where resistant layers are present in the PLD, offering resistance during the headward erosion and poleward retreat of the scarps. Steep slopes that formed under these circumstances enhance the flow of down-scarp katabatic winds. On the basis of these observations, we reject the fluvial outflood hypothesis for the origin of the north polar chasmata and embrace a wind erosion model for their long-term development. In the aeolian model, off-pole katabatic winds progressively remove materials from the steep slopes below chasmata scarps, undermining resistant layers at the tops of scarps and causing retreat by headward erosion. Assuming a minimum age for the onset of formation of Chasma Boreale (10 5 yr) results in a maximum volumetric erosion rate of 0.35 km 3 yr −1 . Removal of this volume of material from the equator-facing wall and head scarps of chasma would require a rate for scarp retreat of 0.5 m yr −1 .

Thermal modelling of the Larderello geothermal field (Tuscany, Italy)

We present a 3-D thermal model of the Larderello geothermal field (Tuscany) to evaluate (1) the extent and contribution of the heat transfer mechanisms (conduction vs. convection) at the intermediate-upper crust levels, (2) the variability of the heat and mass fluxes entering from below and (3) the crucial role of the formation permeability. The model, composed by three main layers, considers the upper 10 km of the crust to better constrain the simulations with experimental data from borehole, fluid inclusion studies and hypocentral distributions. Several sets of simulations were carried out with different bottom boundary temperatures and different formation permeabilities for the two deeper layers. The results indicate that the present temperature (T) and pressure distributions in the Larderello field require deep reservoir rocks with higher permeability than the overlying capping units and underlying intermediate crust. Permeability values of 1 mDarcy for the reservoir rocks are enough to allow fluid convection, if the temperature at 10 km depth is as high as 500 ± 50°C. The presence of localized zones with formation permeability 50–100 times higher than the surrounding rocks strongly favours the migration of over-pressurized fluids, which episodically break through the overburden, feeding the presently exploited geothermal fields.

Mineralogy of the Nili Fossae region with OMEGA/Mars Express data: 1. Ancient impact melt in the Isidis Basin and implications for the transition from the Noachian to Hesperian

The Nili Fossae region located on the northwestern quadrant of the Isidis Basin, Mars, displays superb exposures of bedrock outcrops that reveal mineralogy and composition of the crust. Previous work has shown that this region exhibits the largest exposures of olivine‐dominated rock units on Mars. Visible‐infrared imaging spectrometer data acquired by OMEGA were calibrated to surface reflectance and analyzed to determine surface mineralogy. The dominant minerals identified are iron‐bearing mafic silicates (low‐ and high‐calcium pyroxene, olivine) and water‐bearing phyllosilicate (iron‐rich smectite clay). The strength and position of mineral absorption features were used to produce mineral indicator maps for the dominant species, and the maps were integrated with high‐resolution imaging from the THEMIS, MOC, and HRSC instruments, and MOLA topography. We show that olivine and phyllosilicate occur in spatially distinct outcrops; the olivine‐bearing rock unit is a meters‐ to tens of meters‐thick cap unit resting on phyllosilicate‐bearing bedrock, and the phyllosilicate units predate the Isidis basin‐forming event. On the basis of superposition, crosscutting, and geomorphic relationships, we interpret the emplacement of the olivine‐bearing units as having been contemporaneous with the Isidis impact event. By analogy with the Orientale basin on the Moon, we propose that the olivine‐bearing unit represents the surface exposure of the impact melt from the Isidis impact event. These results demonstrate that large regions of crust had been altered in the presence of water prior to the date of the Isidis basin‐forming event in the Late Noachian (≈3.96 Ga).

Synthesis and NMR characterization of β‐alanine‐bridged hemispherodextrin, a very efficient chiral selector in EKC

A capped derivative of beta-CD (THALAH) was synthesized and characterized by NMR spectroscopy at different pH values. A trehalose moiety, bonded through beta-alanine bridges to the CD cavity, is included in the capping unit, giving peculiar properties to this molecule. The hemispherodextrin thus obtained was tested as a chiral selector in EKC. At neutral pH, the monocationic species of THALAH behaves as a very efficient selector separating successfully all the 11 tested enantiomeric pairs of dansyl-derivatives of amino acids, some of them even at concentrations as low as 0.15 mM. The differences observed in the migration order among the different systems give suggestions about the mechanism of molecular recognition between the selector and the analytes.