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This work reports the synthesis of cubic morphology self-assemblies formed by AgNPs inside delimited by AgCl crystals using Losselia mexicana (L. Mexicana) leaf extract at room temperature. At the same time, an attempt was made to replicate the synthesized products using an aqueous extract of Sedum praealtum (S. praealtum), discussing the results obtained. Likewise, the photocatalytic properties of the assemblies in the degradation of methylene blue (MB) were measured. UV–Vis, XRD, SEM, TEM, and FTIR techniques characterized the morphology and crystal structure of the experimental results. SEM micrographs show that particles obtained by L. mexicana have a cube-shaped morphology and an average size of 357 nm. TEM studies also demonstrate that the cube-shaped assemblies contained AgNPs bounded by AgCl crystals. The SEM analysis obtained from the products synthesized with S. praealtum extract indicates the presence of both AgNPs and AgCl, although not assembled but as independent crystals. XRD patterns confirmed the presence of AgCl and Ag fcc crystalline phases in the products obtained with both plant extracts. AgNPs/AgCl cubic particles were more efficient than AgNPs in MB dye degradation. Thus, self-assembled AgNPs/AgCl particles that show promise as excellent catalysts for environmental applications in wastewater treatment were achieved. [ABSTRACT FROM AUTHOR]

MEK1 interactions with B-Raf and KSR1 are key steps in Ras/Raf/MEK/ERK signaling. Despite this, vital mechanistic details of how these execute signal transduction are still enigmatic. Among these is why, despite B-Raf and KSR1 kinase domains similarity, the B-Raf/MEK1 and KSR1/MEK1 complexes have distinct contributions to MEK1 activation, and broadly, what is KSR1’s role. Our molecular dynamics simulations clarify these still unresolved ambiguities. Our results reveal that the proline-rich (P-rich) loop of MEK1 plays a decisive role in MEK1 activation loop (A-loop) phosphorylation. In the inactive B-Raf/MEK1 heterodimer, the collapsed A-loop of B-Raf interacts with the P-rich loop and A-loop of MEK1, minimizing MEK1 A-loop fluctuation and preventing it from phosphorylation. In the active B-Raf/MEK1 heterodimer, the P-rich loop moves in concert with the A-loop of B-Raf as it extends. This reduces the number of residues interacting with MEK1 A-loop, allowing increased A-loop fluctuation, and bringing Ser222 closer to ATP for phosphorylation. B-Raf αG-helix Arg662 promotes MEK1 activation by orienting Ser218 towards ATP. In KSR1/MEK1, the KSR1 αG-helix has Ala826 in place of B-Raf Arg662. This difference results in much fewer interactions between KSR1 αG-helix and MEK1 A-loop, thus a more flexible A-loop. We postulate that if KSR1 were to adopt an active configuration with an extended A-loop as seen in other protein kinases, then the MEK1 P-rich loop would extend in a similar manner, as seen in the active B-Raf/MEK1 heterodimer. This would result in highly flexible MEK1 A-loop, and KSR1 functioning as an active, B-Raf-like, kinase. [ABSTRACT FROM AUTHOR]

Prion replication results from the autocatalytic templated assisted conversion of the host-encoded prion protein PrPC into misfolded, polydisperse PrPSc conformers. Structurally distinct PrPSc conformers can give rise to multiple prion strains. Within and between prion strains, the biological activity (replicative efficacy and specific infectivity) of PrPSc assemblies is size dependent and thus reflects an intrinsic structural heterogeneity. The contribution of such PrPSc heterogeneity across species prion adaptation, which is believed to be based on fit adjustment between PrPSc template(s) and host PrPC, has not been explored. To define the structural-to-fitness PrPSc landscape, we measured the relative capacity of size-fractionated PrPSc assemblies from different prion strains to cross mounting species barriers in transgenic mice expressing foreign PrPC. In the absence of a transmission barrier, the relative efficacy of the isolated PrPSc assemblies to induce the disease is like the efficacy observed in the homotypic context. However, in the presence of a transmission barrier, size fractionation overtly delays and even abrogates prion pathogenesis in both the brain and spleen tissues, independently of the infectivity load of the isolated assemblies. Altering by serial dilution PrPSc assembly content of non-fractionated inocula aberrantly reduces their specific infectivity, solely in the presence of a transmission barrier. This suggests that synergy between structurally distinct PrPSc assemblies in the inoculum is requested for crossing the species barrier. Our data support a mechanism whereby overcoming prion species barrier requires complementation between structurally distinct PrPSc assemblies. This work provides key insight into the "quasispecies" concept applied to prions, which would not necessarily rely on prion substrains as constituent but on structural PrPSc heterogeneity within prion population. [ABSTRACT FROM AUTHOR]

How should the governance system in a non-membership non-profit organization be designed? This organizational form has no shareholders; instead, donors provide funds. Thus, at the organizational level, the board of directors could have all the power. Under this legal form, who controls the board? If too powerful, boards could misuse resources or distract the organization from its foundational goals. We examine the case of private higher education institutions (HEIs) in Colombia and the balance of power in university governance systems which feature this organizational form. Most HEIs in our sample have a kind of assembly of representatives as the governance body with the highest authority and able to appoint and control the board. We specifically discuss the assemblies’ reason for being, structure, and functions in private HEIs in Colombia. We analyze a total of 204 HEI governance structures and find governance arrangements with the characteristics of an assembly of representatives in 154 (75.9%). Our analysis highlights features in some of these governance bodies that could lead to overly powerful assemblies (e.g., founder donors with tenure for life). Clearly, a proper balance of power is required to avoid rent-seeking behaviors or the pursuit of harmful private non-monetary benefits from assembly members as well as boards. [ABSTRACT FROM AUTHOR]

A non-invasive implementation of the Latin domain decomposition method for frictional contact problems is described. The formulation implies to deal with mixed (Robin) conditions on the faces of the subdomains, which is not a classical feature of commercial software. Therefore we propose a new implementation of the linear stage of the Latin method with a non-local search direction built as the stiffness of a layer of elements on the interfaces. This choice enables us to implement the method within the open source software Code_Aster, and to derive 2D and 3D examples with similar performance as the standard Latin method. [ABSTRACT FROM AUTHOR]

Porous TiO were assembled by evaporating or refluxing TiO colloid, which was obtained by dispersing the TiO nanoparticles with a crystallite size ( d) of 3.2 nm into water or ethanol without any additives. Porous transparent bulk TiO was obtained by evaporating the TiO-CHOH colloid at room temperature for 2 weeks, while porous TiO nanospheres were assembled by refluxing the TiO-HO colloid at 80 °C for 36 h. Both of the porous TiO architectures were pore-size-adjustable depending on the further treating temperature. Porous TiO nanospheres exhibited enhanced photocatalysis activity compared to the nanoparticles. [ABSTRACT FROM AUTHOR]

The native whey proteins have been intensively used in a multitude of food applications due to their high nutritional, biological, and versatile technofunctional properties. The range of applications of whey proteins has further been extended in the last decades by the use of whey protein aggregates offering new technofunctional properties. These properties are directly dependent on the structure of whey protein aggregates, i.e., their size, shape, density, surface properties, and the type of bonds maintaining proteins together in the aggregates. In this review, after a brief description of the major whey proteins, we examine the most important advances reported to date pertaining to the available approaches to modify the structure of whey proteins for specific functionalities. Our laboratory, Science and Technology of Milk and Eggs, has contributed significantly to the advancement of knowledge on the structure-function relationships of whey proteins either in the native or denatured/aggregated forms. Our expertise and research approaches are highlighted throughout some selected results accumulated during the last decade in comparison with results from the literature. [ABSTRACT FROM AUTHOR]

Microfiber assemblies prepared from ellagic acid (EA) were functionalized with histidine (His) and dispersed in hyaluronic acid (HA) hydrogel microstructures. Swelling studies indicated that the hybrids had a relatively lower water uptake compared to HA and was pH dependent. The percentage swelling ratio for EA-His-HA hybrids was 48 % when 0.04 mg/mL of HA was incorporated and increased to 70 % when 1.2 mg/mL HA was integrated. Release studies using the dye crystal violet (CV) as a model drug showed that the rates were concentration-dependent. Further the hybrids were found to be thermally stable compared to HA. Cellular toxicity assays performed with normal rat kidney (NRK) cells indicated biocompatibility and adherence of the hybrids to the cells. Thus, we have developed a new family of hybrid hydrogels which readily formed on the EA-His functionalized microfibers and may have potential applications in drug delivery or tissue regeneration applications. [ABSTRACT FROM AUTHOR]

The separation of surface-enhanced raman scattering (SERS)-active Ag-multi-nanoparticle (NP) assemblies by low melting point agarose gel electrophoresis was accomplished here by controlling surface charge using NP capping agents, and the pore size of agarose gel matrix. Detailed transmission electron microscopy analysis of excised gel fractions showed dimers and small clusters to have the greatest SERS activity and a mobility in between the monomers and large aggregates. This strategy enables one to: (1) stabilize small multispherical Ag clusters against further aggregation during purification; (2) fractionate and recover spherical assemblies by nuclearity; and (3) analyze SERS-enhancements for each fraction to optimize purification conditions. [ABSTRACT FROM AUTHOR]

In this study, we probed the biomimetic formation of gallic acid (GA)-ZnO nanoparticle hybrids. It was found that the morphologies formed were dependent upon pH values, resulting in GA-ZnO hybrids of varying shapes such as micro or nanoplates or fibers. The formed supramolecular GA-ZnO hybrids were found to be luminescent as indicated by confocal microscopy and were utilized for the photocatalytic degradation of the organic dye methylene blue. We also explored the bactericidal effects of the hybrids on Staphylococcus aureus ( S. aureus) as well as Escherichia Coli ( E. Coli). Thus, we have developed a new class of shape-controlled nanohybrid assemblies via mild, green synthetic methods that may be utilized for photocatalytic degradation for environmental remediation as well as for antibacterial applications. [ABSTRACT FROM AUTHOR]

This paper discusses the factors that affect the fire resistance performance of lightweight wood frame unrestrained floor assemblies protected with Type X gypsum board ceiling finishes. Twenty-two fire resistance experiments were conducted on full-scale load-bearing wood joist floor assemblies using the ULC standard fire exposure time–temperature curve that is similar to ASTM E119 standard. Parameters investigated in this study include the effects of gypsum board screws spacing from board edges, insulation installation, insulation type, joist spacing for assemblies with gypsum board attached to resilient channels, joist depth, resilient channel installation, resilient channel spacing, sub-floor topping, number of sub-floor layers, and load magnitude. The impact of these parameters on the fire resistance of wood joist frame floor assemblies is discussed. The fire resistance of wood frame floors appears essentially to be governed by the gypsum board screw spacing from the board edges and the type of insulation in assemblies with one layer of gypsum board and by the resilient channel spacing and the gypsum board screw spacing from the board edges in assemblies with two layers of gypsum board. The effects of other parameters in assemblies with two layers of gypsum board such as the joist spacing where the gypsum boards are attached to resilient channels, installation of resilient channels, insulation installation, insulation type, adding gyp-crete topping above the sub-floor and number of sub-floor layers on fire resistance are relatively insignificant. [ABSTRACT FROM AUTHOR]

This paper examines the use of a series of three low tech interactive assemblies that have been exhibited by the authors in a range of fairs, expositions and galleries. The paper does not present novel technical developments, but rather uses the low tech assemblies to help scope out the design space for CSCW in museums and galleries and to investigate the ways in which people collaboratively encounter and explore technological exhibits in museums and galleries. The bulk of the paper focuses on the analysis of the use of one interactive installation that was exhibited at the Sculpture, Objects and Functional Art (SOFA) Exposition in Chicago, USA. The study uses audio-visual recordings of interaction with and around the work to consider how people, in and through their interaction with others, make sense of an assembly of traditional objects and video technologies. The analysis focuses on the organised practices of ‘assembly’ and how ‘assembling’ the relationship between different parts of the work is interactionally accomplished. The analysis is then used to develop a series of ‘design sensitivities’ to inform the development of technological assemblies to engender informal interaction and sociability in museums and galleries. [ABSTRACT FROM AUTHOR]

Binding energies of the interaction of collagen like triple helical peptides with a series of polyphenols, viz. gallic acid, catechin, epigallocatechingallate and pentagalloylglucose have been computed using molecular modelling approaches. A correlation of calculated binding energies with the interfacial molecular volumes involved in the interaction is observed. Calculated interface surface areas for the binding of polyphenols with collagen-like triple helical peptides vary in the range of 60-210 Å and hydrogen bond lengths vary in the range of 2.7-3.4 Å. Interfacial molecular volumes can be calculated from the solvent inaccessible surface areas and hydrogen bond lengths involved in the binding of polyphenols to collagen. Molecular aggregation of collagen in the presence of some polyphenols and chromium (III) salts has been probed experimentally in monolayer systems. The monolayer arrangement of collagen seems to be influenced by the presence of small molecules like formaldehyde, gluteraldehyde, tannic acid and chromium (III) salts. A fractal structure is observed on account of two-dimensional aggregation of collagen induced by tanning species. Atomic force microscopy has been employed to probe the topographic images of two-dimensional aggregation of collagen induced by chromium (III) salts. A case is made that long-range ordering of collagen by molecular species involved in its stabilisation is influenced by molecular geometries involved in its interaction with small molecules. [ABSTRACT FROM AUTHOR]

This paper describes a new method for inserting parts with very close clearance in the assembly process. The inserting motion becomes smooth and easy by the application of ultrasonic vibration to either the peg or the hole to be mated. In the experiments, longitudinal vibration and/or bending vibration were applied to the peg by using an ultrasonic exciter. Smooth mating with a clearance of less than several micrometers was realised by a robot under rough control to about several hundred micrometers. This effect is due to the result of the reduction of the apparent friction and the generation of surface force on the parts' surfaces. [ABSTRACT FROM AUTHOR]

The photochemistry and photophysics of a series of stilbene-functionalized fatty acids (SFA) have been examined in homogeneous solutions, supported Langmuir-Blodgett assemblies, and as guests in phospholipid bilayers and micellar dispersions. The spectroscopic characteristics of stilbene-functionalized derivatives of phosphatidyl choline (SFA-PC) have also been examined in organic solvents, aqueous dispersions and aqueous solution containing an excess of dipalmitoyl choline (DPPC), as well as in aqueous-methanol solutions containing γ-cyclodextrin. Langmuir-Blodgett assemblies of individual SFAs, as well as mixtures of various SFAs, exhibit spectroscopic properties (blue-shifted absorbance and red-shifted fluorescence relative to those observed in organic solvents) consistent with the formation of an 'H' aggregate. The same effect is observed for SFA-PCs in aqueous dispersions and in aqueous-methanol solutions containing γ-cyclodextrin. The 'H' aggregate is found to be the preferred geometric orientation of the stilbene chromophores which may correspond to an energy minimum for the systems investigated. Preliminary studies with SFA-PC in methanol-water solutions containing γ-cyclodextrin suggest that an association of only two stilbene chromophores is required to form the 'H' aggregate. [ABSTRACT FROM AUTHOR]