Contradictory Properties Research Articles

Robustness and evolvability of heterogeneous cell populations.

Biological systems are endowed with two fundamental but seemingly contradictory properties: robustness, the ability to withstand environmental fluctuations and genetic variability; and evolvability, the ability to acquire selectable and heritable phenotypic changes. Cell populations with heterogeneous genetic makeup, such as those of infectious microbial organisms or cancer, rely on their inherent robustness to maintain viability and fitness, but when encountering environmental insults, such as drug treatment, these populations are also poised for rapid adaptation through evolutionary selection. In this study, we develop a general mathematical model that allows us to explain and quantify this fundamental relationship between robustness and evolvability of heterogeneous cell populations. Our model predicts that robustness is, in fact, essential for evolvability, especially for more adverse environments, a trend we observe in aneuploid budding yeast and breast cancer cells. Robustness also compensates for the negative impact of the systems’ complexity on their evolvability. Our model also provides a mathematical means to estimate the number of independent processes underlying a system’s performance and identify the most generally adapted subpopulation, which may resemble the multi-drug-resistant “persister” cells observed in cancer.

Biomimetic Viruslike and Charge Reversible Nanoparticles to Sequentially Overcome Mucus and Epithelial Barriers for Oral Insulin Delivery.

Nanoparticles (NPs) for oral delivery of peptide/protein drugs are largely limited due to the coexistence of intestinal mucus and epithelial barriers. Sequentially overcoming these two barriers is intractable for a single nanovehicle due to the requirements of different or even contradictory surface properties of NPs. To solve this dilemma, a mucus-penetrating virus-inspired biomimetic NP with charge reversal ability (P-R8-Pho NPs) was developed by densely coating poly(lactic- co-glycolic acid) NPs with cationic octa-arginine (R8) peptide and specific anionic phosphoserine (Pho). The small size (81.81 nm) and viruslike neutral charged surface (-2.39 mV) of the biomimetic NPs achieved rapid mucus penetration, which was almost equal to that of the conventional PEGylated mucus-penetrating nanoparticles. The hydrolysis of surface-anchored anionic Pho was achieved by intestinal alkaline phosphatase, which led to the turnover of ζ potential to positive (+7.37 mV). This timely charge reversal behavior also exposed cationic R8 peptide and induced efficient cell-penetrating peptide (CPP)-mediated cellular uptake and transepithelial transport on Caco-2/E12 cocultured cell model. What's more, P-R8-Pho NPs showed excellent stability in simulated gastrointestinal conditions and enhanced absorption in intestine in vivo. Finally, oral administration of insulin-loaded P-R8-Pho NPs enabled to induce a preferable hypoglycemic effect and a 1.9-fold higher oral bioavailability was achieved compared with single CPP-modified P-R8 NPs on diabetic rats. The combinative application of biomimetic mucus-penetrating strategy and enzyme-responsive charge reversal strategy in a single nanovehicle could sequentially overcome mucus and epithelial barriers, thus showing great potential for the oral peptide/protein delivery.

An Epidermis-like Hierarchical Smart Coating with a Hardness of Tooth Enamel.

We overcome the fundamental dilemma in achieving hard materials with self-healing capability by integrating an epidermis-like hierarchical stratified structure with attractive mechanical and barrier properties of graphene oxide and show that such biomimetic design enables a smart hierarchical coating system with a synergetic healing effect and a record-high stiffness (31.4 ± 1.8 GPa)/hardness (2.27 ± 0.09 GPa) among all self-healable polymeric films even comparable to that of tooth enamel. A quasi-linear layer-by-layer (LBL) film with constituent graphene oxide is deposited on top of an exponential LBL counterpart as a protective hard layer, forming a hierarchical stratified assembly mimicking the structure of epidermis. The hybrid multilayers can achieve a complete restoration after scratching thanks to the mutual benefit: The soft underneath cushion can provide additional polymers to assist the recovery of the outer hard layer, which in turn can be a sealing barrier promoting the self-healing of the soft layer during stimulated polymer diffusion. The presenting hybridization mode of LBL assembly represents a promising tool for integrating seemingly contradictory properties in artificial materials with potential performances surpassing those in nature.

Bioinspired Flexible and Tough Layered Peptide Crystals.

One major challenge of functional material fabrication is combining flexibility, strength, and toughness. In several biological and artificial systems, these desired mechanical properties are achieved by hierarchical architectures and various forms of anisotropy, as found in bones and nacre. Here, it is reported that crystals of N-capped diphenylalanine, one of the most studied self-assembling systems in nanotechnology, exhibit well-ordered packing and diffraction of sub-Å resolution, yet display an exceptionally flexible nature. To explore this flexibility, the mechanical properties of individual crystals are evaluated, assisted by density functional theory calculations. High-resolution scanning electron microscopy reveals that the crystals are composed of layered self-assembled structures. The observed combination of strength, toughness, and flexibility can therefore be explained in terms of weak interactions between rigid layers. These crystals represent a novel class of self-assembled layered materials, which can be utilized for various technological applications, where a combination of usually contradictory mechanical properties is desired.

Iterated privation and positive predication

The standard rule of single privative modification replaces privative modifiers by Boolean negation. This rule is valid, for sure, but also simplistic. If an individual a instantiates the privatively modified property (MF) then it is true that a instantiates the property of not being an F, but the rule fails to express the fact that the properties (MF) and F have something in common. We replace Boolean negation by property negation, enabling us to operate on contrary rather than contradictory properties. To this end, we apply our theory of intensional essentialism, which operates on properties (intensions) rather than their extensions. We argue that each property F is necessarily associated with an essence, which is the set of the so-called requisites of F that jointly define F. Privation deprives F of some but not all of its requisites, replacing them by their contradictories. We show that properties formed from iterated privatives, such as being an imaginary fake banknote, give rise to a trifurcation of cases between returning to the original root property or to a property contrary to it or being semantically undecidable for want of further information. In order to determine which of the three forks the bearers of particular instances of multiply modified properties land upon we must examine the requisites, both of unmodified and modified properties. Requisites underpin our presuppositional theory of positive predication. Whereas privation is about being deprived of certain properties, the assignment of requisites to properties makes positive predication possible, which is the predication of properties the bearers must have because they have a certain property formed by means of privation.

Intelligent optimal control for the crawler vehicle with semi-active suspension using modified staged continuous tabu search algorithm

This paper proposes a novel intelligent optimal control strategy for crawler vehicles with semi-active suspension. The proposed control strategy aims at improving vehicle ride comfort by addressing contradictory suspension properties requirements of ride comfort and handling stability simultaneously. After establishing seven degrees of freedom dynamic model of the crawler vehicle, a comprehensive evaluation index is developed to trade off among various vehicle performances, which include ride comfort, damper thermal reliability, elastic element fatigue and handling stability. Then, using modified staged continuous tabu search (MSCTS) algorithm, the optimal control efforts of semi-active suspension, damping ratios, are determined by minimizing the cost function defined by the comprehensive evaluation index. Demonstrated by simulations with triangle convex block and random ground roughness excitations, MSCTS control strategy can successfully improve ride comfort performance and achieve the optimal comprehensive performance as well.

Harnessing the Power of Plastics: Nanostructured Polymer Systems in Lithium-Ion Batteries

Nanostructure-forming polymers have tremendous potential to enhance the performance and safety of lithium-ion batteries (LiBs) as a result of their ability to simultaneously optimize often contradictory properties, such as ionic conductivity and mechanical stability, in a single material. These macromolecules can be harnessed in both LiB electrolyte and electrode components. With respect to electrolytes, advances in salt-doped and single-ion systems are highlighted herein with a focus on strategies that improve conductivities to rival that found in gel and liquid electrolytes, while also permitting further enhancements in electrochemical and mechanical stability. In the arena of electrodes, three major functions are considered: binders to maximize active material efficiency, polymer electrodes to enable fully organic LiBs, and sacrificial constructs that template high surface area, well-ordered metal oxide or metallic electrodes to improve electrode capacity. Additionally, the application of theory and si...

The Theft of Ideas as a Cybercrime: Downloading and Changes in the Business Model of the Creative Arts

This paper focuses on copyright and critically explores some of the arguments that are used to justify intellectual property law in this digital and networked age and some of the tactics used to protect them. More specifically, this paper explores the theft of creative ideas as a cybercrime and focuses upon the contradictory intellectual property issues raised by the digital and networked technologies of downloading via file sharing. Technologies, which, like each previous new form of communications technology has ‘disrupted’ predominant business models and challenged the assumptions behind them. In the case of the creative arts, the ‘intellectual land grab’ for control over the ideas domain remains as contentious as ever. In this case, digital forms of music, film and, for that matter many other expressions of the creative arts. On the one hand, there has been as there still is, a distinct move to restrict and disincentivise downloading via file sharing by criminalizing what was otherwise a civil space - arguably making it even more attractive as a form of deviance. On the other hand technologies are being developed to automatically censor IP content in live streams, reaffirming downloading via file sharing as a form of deviance. Furthermore, there is the simultaneous irony that technologised and legally unstable income stream collection practices, such as ‘speculative invoicing’ - the sending of invoices to alleged copyright infringers demanding payment else face further legal action - are corrupting the very process that they seek to protect. All, against the background of the curious paradox of circulation and control which appears to demand that successful management of IP has to achieve a critical balance between restricting it enough to prevent it from becoming too diluted and losing its public appeal and value, and letting it roam free enough for consumers to buy into it and creators incorporate the themes into the next generation of popular culture - itself a contradiction to existing intellectual property ‘central origin myths’.

Some thoughts on Experiencing Time

This paper examples several arguments from Simon Prosser's book Experiencing Time. His argument against the doctrine of the specious present is applauded. His argument that even if time passes, nothing can detect the passage of time, is questioned. Also challenged are his claims that our experience represents things as enduring, rather than perduring, and represents things as having contradictory properties.

Superstretchable Nacre-Mimetic Graphene/Poly(vinyl alcohol) Composite Film Based on Interfacial Architectural Engineering.

Through designing hierarchical structures, particularly optimizing the chemical and architectural interactions at its inorganic/organic interface, nacre has achieved an excellent combination of contradictory mechanical properties such as strength and toughness, which is highly demanded yet difficult to achieve by most synthetic materials. Most techniques applied to develop nacre-mimetic composites have been focused on mimicking the "brick-and-mortar" structure, but the interfacial architectural features, especially the asperities and mineral bridges of "bricks", have been rarely concerned, which are of equal importance for enhancing mechanical properties of nacre. Here, we used a modified bidirectional freezing method followed by uniaxial pressing and chemical reduction to assemble a nacre-mimetic graphene/poly(vinyl alcohol) composite film, with both asperities and bridges introduced in addition to the lamellar layers to mimic the interfacial architectural interactions found in nacre. As such, we have developed a composite film that is not only strong (up to ∼150.9 MPa), but also tough (up to ∼8.50 MJ/m3), and highly stretchable (up to ∼10.44%), difficult to obtain by other methods. This was all achieved by only interfacial architectural engineering within the traditional "brick-and-mortar" structure, without introducing a third component or employing chemical cross-linker as in some other nacre-mimetic systems. More importantly, we believe that the design principles and processing strategies reported here can also be applied to other material systems to develop strong and stretchable materials.

Characterization of functionally graded Al-SiCp metal matrix composites manufactured by centrifugal casting

The design of metal matrix composites can be enhanced by integrating the concept of functionally graded materials (FGM) to produce engineering materials with tailored contradictory properties that suit multifunctioning components. The present investigation focuses on characterization of functionally graded metal matrix composites (FGMMCs) based on pure aluminium matrix reinforced with different percentages and sizes of SiC particles. The investigated FGMs have been produced by horizontal centrifugal casting process under different conditions. Microstructure investigation, tensile, hardness and wear rate measurements have been correlated with the size and percentage of SiC particles and their distribution/gradient across the thickness of the cast tubes resulting from the used casting parameters.

Proper names used as modifiers: a comprehensive functional analysis

My central concern is the special use of proper names in the English noun phrase first discussed by Rosenbach (2006, 2007, 2010; Koptjevskaja-Tamm & Rosenbach 2005): proper names which are used as modifiers with an identifying function, e.g.theBushadministration(‘Which administration does the noun phrase refer to? The one headed by Bush’). On the basis of a corpus study, I argue that existing analyses of Rosenbach (2007) and Schlücker (2013) fail to account for all cases; they also fail to capture the seemingly contradictory syntactic and functional properties of these proper names in a unified way. My alternative analysis is framed within Halliday's (1994) functional model of the English noun phrase, but radically thinks beyond the typical association of functions with word classes (see also Rijkhoff 2009). My proposal is that the majority of these proper names can be analysed as epithets, a function typically associated with adjectival modifiers such astheredcar. A smaller set, proper name modifiers such asaKerrysupporter, are analysed as complements (Payne & Huddleston 2002). I end by discussing the implications of this dual analysis for another open question, whether proper name modifiers are morphosyntactically phrasal modifiers or part of compounds.

Gauthier and the Prisoner’s Dilemma

The Prisoner’s Dilemma (PD) plays a central, but shifting, role in David Gauthier’s moral theorizing. In “Morality and Advantage,” it provides a model, demonstrating how morality can have seemingly contradictory properties. In Morals by Agreement, it poses a special problem for the view that moral behaviour is individually rational. Authorities on game theory have subsequently disputed the idea that the PD is an appropriate tool for thinking about moral theory. In the first part of this paper, I examine the roles of the PD in Gauthier’s writings. In the second part, I outline a project, with both descriptive and normative components, that develops the insights of “Morality and Advantage” while preserving it from the game theorists’ attack.

Unusual Dual Superlyophobic Surfaces in Oil-Water Systems: The Design Principles.

Thermodynamically unusual surfaces that possess two contradictory wetting properties, i.e., underoil superhydrophobicity and underwater superoleophobicity, are prepared by the combination of re-entrant topography and delicately matched surface chemistry. The preparation of such extraordinary surfaces relies on two key design criteria and employs a metastable state effect in solid-oil-water systems.

2D Covalent Metals: A New Materials Domain of Electrochemical CO2 Conversion with Broken Scaling Relationship.

Toward a sustainable carbon cycle, electrochemical conversion of CO2 into valuable fuels has drawn much attention. However, sluggish kinetics and a substantial overpotential, originating from the strong correlation between the adsorption energies of intermediates and products, are key obstacles of electrochemical CO2 conversion. Here we show that 2D covalent metals with a zero band gap can overcome the intrinsic limitation of conventional metals and metal alloys and thereby substantially decrease the overpotential for CO2 reduction because of their covalent characteristics. From first-principles-based high-throughput screening results on 61 2D covalent metals, we find that the strong correlation between the adsorption energies of COOH and CO can be entirely broken. This leads to the computational design of CO2-to-CO and CO2-to-CH4 conversion catalysts in addition to hydrogen-evolution-reaction catalysts. Toward efficient electrochemical catalysts for CO2 reduction, this work suggests a new materials domain having two contradictory properties in a single material: covalent nature and electrical conductance.

Stiffer but More Healable Exponential Layered Assemblies with Boron Nitride Nanoplatelets.

Self-healing ability and the elastic modulus of polymeric materials may seem conflicting because of their opposite dependence on chain mobility. Here, we show that boron nitride (BN) nanoplatelets can simultaneously enhance these seemingly contradictory properties in exponentially layer-by-layer-assembled nanocomposites as both surface coatings and free-standing films. On one hand, embedding hard BN nanoplatelets into a soft hydrogen bonding network can enhance the elastic modulus and ultimate strength through effective load transfer strengthened by the incorporation of interfacial covalent bonding; on the other hand, during a water-enabled self-healing process, these two-dimensional flakes induce an anisotropic diffusion, maintain the overall diffusion ability of polymers at low loadings, and can be "sealing" agents to retard the out-of-plane diffusion, thereby hampering polymer release into the solution. A detailed mechanism study supported by a theoretical model reveals the critical parameters for achieving a complete self-healing process. The insights gained from this work may be used for the design of high-performance smart materials based on other two-dimensional fillers.

Enhanced Oral Delivery of Protein Drugs Using Zwitterion-Functionalized Nanoparticles to Overcome both the Diffusion and Absorption Barriers.

Oral delivery of protein drugs based on nanoparticulate delivery system requires permeation of the nanoparticles through the mucus layer and subsequent absorption via epithelial cells. However, overcoming these two barriers requires very different or even contradictory surface properties of the nanocarriers, which greatly limits the oral bioavailability of macromolecular drugs. Here we report a simple zwitterions-based nanoparticle (NP) delivery platform, which showed a great potency in simultaneously overcoming both the mucus and epithelium barriers. The dense and hydrophilic coating of zwitterions endows the NPs with excellent mucus penetrating ability. Moreover, the zwitterions-based NPs also possessed excellent affinity with epithelial cells, which significantly improved (4.5-fold) the cellular uptake of DLPC NPs, compared to PEGylated NPs. Our results also indicated that this affinity was due to the interaction between zwitterions and the cell surface transporter PEPT1. Moreover, the developed NPs loaded with insulin could induce a prominent hypoglycemic response in diabetic rats following oral administration. These results suggest that zwitterions-based NPs might provide a new perspective for oral delivery of protein therapeutics.

Influencia de la potencia de deposición en las propiedades eléctricas y ópticas de películas delgadas de Sn1-xO2Nbx obtenidas por pulverización catódica

In a solid, the electrical conductivity and optical transparency seem to be two contradictory physical properties. Conductive materials are opaque, and transparent solids are electrical insulators. Combinations of these two physical properties in a material make it appropriate for application in many optoelectronic devices. The coincidence of these two properties has been mainly ascribed to point defects in the crystal lattice. In this work we performed structural, electrical and optical characterization of thin films of one of the most promising transparent conductive oxides Sn 1-x O 2 Nb x. The films were grown on glass substrates by RF magnetron sputtering technique. As the deposition power was varied, it was found that the electrical conductivity of the films increased with increasing power deposition, and they showed a preferential growth in the (200) direction. All films exhibited optical transmittance in the visible range larger than 80%

The impossible process: Thermodynamic reversibility

Standard descriptions of thermodynamically reversible processes attribute contradictory properties to them: they are in equilibrium yet still change their state. Or they are comprised of non-equilibrium states that are so close to equilibrium that the difference does not matter. One cannot have states that both change and no not change at the same time. In place of this internally contradictory characterization, the term “thermodynamically reversible process” is here construed as a label for a set of real processes of change involving only non-equilibrium states. The properties usually attributed to a thermodynamically reversible process are recovered as the limiting properties of this set. No single process, that is, no system undergoing change, equilibrium or otherwise, carries those limiting properties. The paper concludes with an historical survey of characterizations of thermodynamically reversible processes and a critical analysis of their shortcomings.

Distributed Hybridization Model for Quantum Critical Behavior in Magnetic Quasicrystals

A quantum critical behavior of the magnetic susceptibility was observed in a quasicrystal containing ytterbium. At the same time, a mixed-valence feature of Yb ions was reported, which appears to be incompatible with the magnetic instability. We derive the magnetic susceptibility by expressing the quasiperiodicity as the distributed hybridization strength between Yb 4f and conduction electrons. Assuming a wide distribution of the hybridization strength, the most f electrons behave as renormalized paramagnetic states in the Kondo or mixed-valence regime, but a small number of f moments remain unscreened. As a result, the bulk magnetic susceptibility exhibits a nontrivial power-law-like behavior, while the average f-electron occupation is that of mixed-valence systems. This model thus resolves two contradictory properties of Yb quasicrystals.