Interlocked Network Research Articles

Cytokine cascade and networks among MSM HIV seroconverters: implications for early immunotherapy.

The timing, intensity and duration of the cytokine cascade and reorganized interrelations in cytokine networks are not fully understood during acute HIV-1 infection (AHI). Using sequential plasma samples collected over three years post-infection in a cohort of MSM HIV-1 seroconvertors, we determined the early kinetics of cytokine levels during FiebigI-IV stages using Luminex-based multiplex assays. Cytokines were quantified and relationships between cytokines were assessed by Spearman correlation. Compared with HIV-negative MSM, HIV-infected individuals had significantly increased multiple plasma cytokines, including GM-CSF, IFN-α2, IL-12p70, IP-10 and VEGF, during both acute and chronic stages of infection. Furthermore, rapid disease progressors (RDPs) had earlier and more robust cytokine storms, compared with slow disease progressors (SDPs) (49.6 days vs. 74.9 days, respectively; 6.7-fold vs. 3.7-fold change of cytokines, respectively), suggesting the faster and stronger cytokine storm during AHI could promote disease progression. On the other hand, HIV-1 infection induced more interlocked cytokines network, establishing new strong correlations and imposing a higher rigidity. There were, respectively, 146 (44.9%) statistically significant correlations of cytokines in RDPs and 241 (74.2%) in SDPs (p < 0.001). This study suggests that immunomodulatory interventions aimed at controlling cytokine storm in AHI may be beneficial to slow eventual disease progression.

Topoisomerase-Based Preparation and AFM Imaging of Multi-Interlocked Circular DNA

Multi-interlocked circular DNA structures have been in high demand for fabricating complicated functional DNA architectures and nanodevices such as molecular switches, shuttles, and motors. Even though various innovative methods have been developed in the past, creation of multi-interlocked circular DNA structures with defined numbers of DNA molecules and linking patterns is still a challenging task nowadays. Here, we propose a top-down decatenation of kinetoplast DNA as a new approach for creating multi-interlocked circular DNA structures. Through optimizing the amount and reaction time of topoisomerase II, we synthesized completely mutually interlocked tricircular, tetra-circular, and oligo-circular DNA structures, which have not yet been acquirable through any other existing synthetic means. The catenation structures of multiple circular DNA were further verified through atomic force microscopic analysis of the backbone overlapping patterns and the circumference. It accordingly is our expectation that the top-down enzymatic approaches could offer a highly interlocked network with defined numbers of circular DNA with simple protocols, and could consequently be beneficial to the design and fabrication of sophisticated functional molecules and nanodevices in the areas of supramolecular chemistry, DNA nanotechnology, and material science.

A honeycomb-cobweb inspired hierarchical core–shell structure design for electrospun silicon/carbon fibers as lithium-ion battery anodes

The silicon/carbon (Si/C) hybrid fibers with a hierarchical core–shell structure are prepared by encapsulating Si nanoparticles in the interconnected hollow carbon fibers (Si@IHCFs) based on a dual coaxial electrospinning technique. For the hierarchical structure, Si nanoparticles are embedded in the honeycomb-like carbon framework in the fiber core, which is further wrapped by the interlocked cobweb-like carbon shell network. As lithium-ion battery anode, the well-defined Si@IHCFs demonstrates a reversible capacity of 903 mAh g−1 and a capacity retention of 89% after 100 cycles with a current density of 0.2 A g−1. With the current density gradually increasing to 2.0 A g−1, the electrode shows a specific capacity of 743 mAh g−1, exhibiting superior rate capability compared to the Si/C fibers with a core–shell but unconnected structure. The excellent electrochemical properties are attributed to the hierarchical core–shell structure and cross-linked network for the Si/C composite fibers. The carbon framework in the core region accommodates the volume expansion of Si by the honeycomb-like pores. And the interconnected carbon shell can not only prevent electrolyte from permeating into the core section, but also improve the electronic conductivity by the connections in the fiber network.

Interlocked positive and negative feedback network motifs regulate β-catenin activity in the adherens junction pathway.

The integrity of epithelial tissue architecture is maintained through adherens junctions that are created through extracellular homotypic protein-protein interactions between cadherin molecules. Cadherins also provide an intracellular scaffold for the formation of a multiprotein complex that contains signaling proteins, including β-catenin. Environmental factors and controlled tissue reorganization disrupt adherens junctions by cleaving the extracellular binding domain and initiating a series of transcriptional events that aim to restore tissue homeostasis. However, it remains unclear how alterations in cell adhesion coordinate transcriptional events, including those mediated by β-catenin in this pathway. Here were used quantitative single-cell and population-level in vitro assays to quantify the endogenous pathway dynamics after the proteolytic disruption of the adherens junctions. Using prior knowledge of isolated elements of the overall network, we interpreted these data using in silico model-based inference to identify the topology of the regulatory network. Collectively the data suggest that the regulatory network contains interlocked network motifs consisting of a positive feedback loop, which is used to restore the integrity of adherens junctions, and a negative feedback loop, which is used to limit β-catenin-induced gene expression.

Timing of circadian genes in mammalian tissues.

Circadian clocks are endogenous oscillators driving daily rhythms in physiology. The cell-autonomous clock is governed by an interlocked network of transcriptional feedback loops. Hundreds of clock-controlled genes (CCGs) regulate tissue specific functions. Transcriptome studies reveal that different organs (e.g. liver, heart, adrenal gland) feature substantially varying sets of CCGs with different peak phase distributions. To study the phase variability of CCGs in mammalian peripheral tissues, we develop a core clock model for mouse liver and adrenal gland based on expression profiles and known cis-regulatory sites. ‘Modulation factors’ associated with E-boxes, ROR-elements, and D-boxes can explain variable rhythms of CCGs, which is demonstrated for differential regulation of cytochromes P450 and 12 h harmonics. By varying model parameters we explore how tissue-specific peak phase distributions can be generated. The central role of E-boxes and ROR-elements is confirmed by analysing ChIP-seq data of BMAL1 and REV-ERB transcription factors.

A two-dimensional analytical model and experimental validation of garter stitch knitted shape memory alloy actuator architecture

Active knits are a unique architectural approach to meeting emerging smart structure needs for distributed high strain actuation with simultaneous force generation. This paper presents an analytical state-based model for predicting the actuation response of a shape memory alloy (SMA) garter knit textile. Garter knits generate significant contraction against moderate to large loads when heated, due to the continuous interlocked network of loops of SMA wire. For this knit architecture, the states of operation are defined on the basis of the thermal and mechanical loading of the textile, the resulting phase change of the SMA, and the load path followed to that state. Transitions between these operational states induce either stick or slip frictional forces depending upon the state and path, which affect the actuation response. A load–extension model of the textile is derived for each operational state using elastica theory and Euler–Bernoulli beam bending for the large deformations within a loop of wire based on the stress–strain behavior of the SMA material. This provides kinematic and kinetic relations which scale to form analytical transcendental expressions for the net actuation motion against an external load. This model was validated experimentally for an SMA garter knit textile over a range of applied forces with good correlation for both the load–extension behavior in each state as well as the net motion produced during the actuation cycle (250% recoverable strain and over 50% actuation). The two-dimensional analytical model of the garter stitch active knit provides the ability to predict the kinetic actuation performance, providing the basis for the design and synthesis of large stroke, large force distributed actuators that employ this novel architecture.

Mesoporous and Macroporous Brookite Thin Films Having a Large Thermal Stability Range

A sol-gel chemistry approach is employed to generate mesoporous and macroporous brookite thin films using Ag ions as dopant species whose thermal stability is well above previously reported literature values for thin films. The Ag ions not only induce the formation of brookite but also participate in its enhanced thermal stability. Despite brookite being metastable in nature, which renders it a challenge to synthesize, it has been prescribed as a potential competitor to anatase. We have used a layer-by-layer approach to generate a mesoporous Ag-doped brookite structure at 500 °C with 95% composition by XRD. This tightly packed mesoporous structure can be described as striated grains of brookite protruding from the surface to form an interlocked network whose thermal stability spans up to 800 °C. The open structure of brookite makes it an apt host for the intercalant Ag species, whose inclusion within the brookite framework is improved by the presence of a stabilizing agent. Both the morphology of the surface and the presence of a stabilization agent for Ag contribute to enhancing its thermal stability. This is in contrast to the thermal stability of the macroporous brookite thin film, which was found to be lower (<700 °C) than that of the mesoporous brookite thin film. The reagents are deliberately chosen to produce a macroporous film in the absence of a stabilizing agent. Ag nodules are observed to be formed at 700 °C, which implies their limited intercalation into the brookite structure, thus rendering them relatively less stable. Moreover, the macroporous film being relatively more relaxed is more susceptible to phase transformation at a higher calcination temperature. Our results provide a platform that paves the way toward better control, thereby leading to a broader technological application of brookite.

Pickering emulsions stabilized by in situ grown biologically active alkyl gallate microneedles

We report on the stabilization of water-in-oil Pickering emulsions through the in situ growth of surface and biologically active alkyl gallate microneedles. Octyl gallate needles are shown to form a rigid interlocked network upon adsorption at the oil–water interface, generating emulsions that are stable for several months. Emulsions containing food-grade oils with potentially high antioxidant and antimicrobial activities were successfully prepared using solely octyl gallate microneedles as the surface active species. The safety and efficacy of alkyl gallates as antioxidant and antimicrobial agents combined with their ability to form strong interwoven needle-like structures at the oil–water interface makes this a promising approach for the preparation of functional, ultrastable Pickering emulsions for food, cosmetic and pharmaceutical applications.

Light-Emitting Conjugated Polymers with Microporous Network Architecture: Interweaving Scaffold Promotes Electronic Conjugation, Facilitates Exciton Migration, and Improves Luminescence

Herein we report a strategy for the design of highly luminescent conjugated polymers by restricting rotation of the polymer building blocks through a microporous network architecture. We demonstrate this concept using tetraphenylethene (TPE) as a building block to construct a light-emitting conjugated microporous polymer. The interlocked network successfully restricted the rotation of the phenyl units, which are the major cause of fluorescence deactivation in TPE, thus providing intrinsic luminescence activity for the polymers. We show positive "CMP effects" that the network promotes π-conjugation, facilitates exciton migration, and improves luminescence activity. Although the monomer and linear polymer analogue in solvents are nonemissive, the network polymers are highly luminescent in various solvents and the solid state. Because emission losses due to rotation are ubiquitous among small chromophores, this strategy can be generalized for the de novo design of light-emitting materials by integrating the chromophores into an interlocked network architecture.

Statecharts for Gene Network Modeling

State diagrams (stategraphs) are suitable for describing the behavior of dynamic systems. However, when they are used to model large and complex systems, determining the states and transitions among them can be overwhelming, due to their flat, unstratified structure. In this article, we present the use of statecharts as a novel way of modeling complex gene networks. Statecharts extend conventional state diagrams with features such as nested hierarchy, recursion, and concurrency. These features are commonly utilized in engineering for designing complex systems and can enable us to model complex gene networks in an efficient and systematic way. We modeled five key gene network motifs, simple regulation, autoregulation, feed-forward loop, single-input module, and dense overlapping regulon, using statecharts. Specifically, utilizing nested hierarchy and recursion, we were able to model a complex interlocked feed-forward loop network in a highly structured way, demonstrating the potential of our approach for modeling large and complex gene networks.

Construction of one-, two- and three-dimensional Cu(I) polymeric architectures containing bis(diphenylphosphino)acetylene and 4,4′-bipyridine linking ligands

One-dimensional {[Cu 2(dppa) 2(4,4′-bipy)(CH 3CN) 2](BF 4) 2 · 2CH 3CN} n ( 1), two-dimensional {[Cu 2(dppa)(4,4′-bipy) 2(CH 3CN) 2](BF 4) 2 · 4CH 2Cl 2 · 4H 2O} n ( 2) and three-dimensional {[Cu 2(dppa)(4,4′-bipy) 3](BF 4) 2 · 2CH 2Cl 2 · 3CH 3CN · 3H 2O} n ( 3) polymeric complexes have been prepared by self-assembly of [Cu(MeCN) 4]BF 4, Ph 2PC CPPh 2 (dppa) and 4,4′-bipyridine (4,4′-bipy) in a 2:2:1, 1:1:1 and 2:2:3 molar ratio, respectively. The structures of 1– 3, determined by an X-ray diffraction study, reveal a linear spring-like architecture for 1, a planar honeycomb grid for 2 and an interlocked adamantoid network for 3.

Hydrothermal Synthesis and Structural Characterization of Two Zinc Coordination Polymers of 1,2‐Di(4‐pyridyl)ethylene and Benzenedicarboxylate

AbstractHydrothermal reactions of Zn(NO3)2·6H2O with 1,2‐di(4‐pyridyl)ethylene (dpe) and 1,4‐benzenedicarboxylate (1,4‐BDC) or 1,3‐benzenedicarboxylate (1,3‐BDC) in water gave rise to two new metal‐organic coordination polymers, [Zn(1,4‐BDC)(dpe)]n (1) and [Zn4O(1,3‐BDC)3(dpe)]n (2). Both compounds were characterized by elemental analysis and IR spectroscopy, and their structures were determined by single crystal X‐ray diffraction. 1 displays a rare 5‐fold interpenetrating 66‐diamondoid framework while 2 possesses an interlocked 3D network formed by inclined interpenetration of 2D (4,4) networks that are constructed by µ4‐oxo tetrazinc Zn4O cores and the bridging dpe and 1,3‐BDC ligands. Thermal and photoluminescent properties of 1 and 2 were also investigated.

The impact of board interlocks on the diffusion of enterprise resource planning systems

This paper is intended to investigate the extent to which board interlocks contribute to the diffusion of ERP technologies in an interlocked network. Controlling for size, we investigate the effect of two network characteristics on the adoption decision of enterprise systems by organisations: the exposure of a firm to other adopters and the centrality of a firm within an interlocked network. In order to test our models, we gathered board members data of the top 1000 Canadian public firms and recorded adoption decisions within this network through the analysis of ERP announcements using keywords co-location. Our research findings suggest evidence of the diffusion of ERP technologies in interlocked networks.

DISJUNCTURES IN THEORY AND PRACTICE: MAKING SENSE OF CHANGE IN AGRICULTURAL DEVELOPMENT AT THE OFFICE DU NIGER, 1920–60

In the introduction to their edited volume International Development and the Social Sciences: Essays on the History and Politics of Knowledge, Frederick Cooper and Randall Packard take on the thorny question of why development policies change and why they sometimes persist or reappear after a period of dormancy. Much recent scholarship has located the reasons for persistence or change in development approaches within international institutions such as multilateral and bilateral aid agencies and Western scientific and social scientific disciplines. Both Arturo Escobar and James Ferguson argue for the existence of a hegemonic development discourse with standardized interventions aimed at ‘solving’ homogenized ‘problems’. Grounded in Western institutions such as the World Bank, this development discourse is maintained by an interlocked network of experts and expertise. In their analyses, development approaches and interventions are minimally affected by the particularities of locale. Other scholars concerned with identifying and understanding significant change in development policy have also focused their studies on Western organizations and disciplines and excluded from their analysis the role that development practice might play in change. But Cooper and Packard challenge scholars to consider the ways in which development policies might be molded by the practice of development, when they note ‘it is not clear that the determinants of these policies are as independent of what goes on at the grassroots as they appear to their authors or their critics to be’.

Magnetization Density in Ferromagnetic TiBe1.8Cu0.2

The distribution of magnetization in the weak itinerant ferromagnetic TiBe/sub 1.8/Cu/sub 0.2/ has been determined by polarized-neutron diffraction. The magnetization resides on the titanium sites forming an interlocked tetrahedral network. No magnetization is present at the beryllium sites, into which copper goes substitutionally.