Computing the F-index of nanostar dendrimers

AbstractDendrimers are highly branched nanostructures and are considered a building block in nanotechnology with a variety of suitable applications. In this paper, a vertex degree-based topological index, namely, the F-index, which is defined as the sum of cubes of a graph's vertex degrees, is studied for certain dendrimers. In this study, we present exact expressions for the F-index and F-polynomial of six infinite classes of nanostar dendrimers

[N]pT Monte Carlo Simulations of the Cluster-Crystal-Forming Penetrable Sphere Model

Certain models with purely repulsive pair interactions can form cluster crystals with multiply-occupied lattice sites. Simulating these models' equilibrium properties is, however, quite challenging. Here, we develop an expanded isothermal-isobaric $[N]pT$ ensemble that surmounts this problem by allowing both particle number and lattice spacing to fluctuate. We apply the method with a Monte Carlo simulation scheme to solve the phase diagram of a prototypical cluster-crystal former, the penetrable sphere model (PSM), and compare the results with earlier theoretical predictions. At high temperatures and densities, the equilibrium occupancy $n_{\mathrm{c}}^{\mathrm{eq}}$ of face-centered cubic (FCC) crystal increases linearly. At low temperatures, although $n_{\mathrm{c}}^{\mathrm{eq}}$ plateaus at integer values, the crystal behavior changes continuously with density. The previously ambiguous crossover around $T\sim0.1$ is resolved

Hydrophobic and hydrophilic au and ag nanoparticles. Breakthroughs and perspectives

This review provides a broad look on the recent investigations on the synthesis, characterization and physico-chemical properties of noble metal nanoparticles, mainly gold and silver nanoparticles, stabilized with ligands of different chemical nature. A comprehensive review of the available literature in this field may be far too large and only some selected representative examples will be reported here, together with some recent achievements from our group, that will be discussed in more detail. Many efforts in finding synthetic routes have been performed so far to achieve metal nanoparticles with well-defined size, morphology and stability in different environments, to match the large variety of applications that can be foreseen for these materials. In particular, the synthesis and stabilization of gold and silver nanoparticles together with their properties in different emerging fields of nanomedicine, optics and sensors are reviewed and briefly commented

The Thermodynamics of Network Coding, and an Algorithmic Refinement of the Principle of Maximum Entropy

The principle of maximum entropy (Maxent) is often used to obtain prior probability distributions as a method to obtain a Gibbs measure under some restriction giving the probability that a system will be in a certain state compared to the rest of the elements in the distribution. Because classical entropy-based Maxent collapses cases confounding all distinct degrees of randomness and pseudo-randomness, here we take into consideration the generative mechanism of the systems considered in the ensemble to separate objects that may comply with the principle under some restriction and whose entropy is maximal but may be generated recursively from those that are actually algorithmically random offering a refinement to classical Maxent. We take advantage of a causal algorithmic calculus to derive a thermodynamic-like result based on how difficult it is to reprogram a computer code. Using the distinction between computable and algorithmic randomness we quantify the cost in information loss associated with reprogramming. To illustrate this we apply the algorithmic refinement to Maxent on graphs and introduce a Maximal Algorithmic Randomness Preferential Attachment (MARPA) Algorithm, a generalisation over previous approaches. We discuss practical implications of evaluation of network randomness. Our analysis provides insight in that the reprogrammability asymmetry appears to originate from a non-monotonic relationship to algorithmic probability. Our analysis motivates further analysis of the origin and consequences of the aforementioned asymmetries, reprogrammability, and computation.Comment: 30 page

AN UPDATED REVIEW ON THE APPLICATION OF DENDRIMERS AS SUCCESSFUL NANOCARRIERS FOR BRAIN DELIVERY OF THERAPEUTIC MOIETIES

It’s been nearly 100 y of effort to study the organization and role of the blood brain-barrier and still, we strive to find better techniques to overcome this barrier to deliver the drugs to the brain effectively with reduced systemic side effects. The advances in nanotechnology have given newer horizons in achieving this goal since the nano-scaled systems can modify an existing drug to have a high degree of sensitivity to the physiological conditions and specificity to reach the target organ. Among the various nanocarriers, dendrimers owing to their unique physical and chemical characteristics, represent a potential therapeutic tool in biomedical and pharmaceutical science. Dendrimers, an established polymeric nanocarrier system of the time, can deliver both drugs and genetic material and are being extensively studied to target the brain. The surface modification of dendrimers can reduce their innate toxicity problems and increase the therapeutic efficacy of brain disorders. This review article is an attempt to update on the potential of dendrimers explored in the past five years as a drug delivery avenue that can be considered as a promising solution in the management of a wide range of disorders affecting the central nervous system, including neoplastic, degenerative, and ischemic conditions. The following search criteria were used to expand the review article with the keywords dendrimers, novel drug delivery, nanoparticles, site-specific drug delivery etc

Understanding the Structure-Function Relationships of Dendrimers in Environmental and Biomedical Applications

We are living an era wherein nanoparticles (NPs) have been widely applied in our lives. Dendrimers are special polymeric NPs with unique physiochemical properties, which have been intensely explored for a variety of applications. Current studies on dendrimers are bottlenecked by insufficient understandings of their structure and dynamic behaviors from a molecular level. With primarily computational approaches supplemented by many other experimental technics, this dissertation aims to establish structure-function relationships of dendrimers in environmental and biomedical applications. More specifically, it thoroughly investigates the interactions between dendrimers and different biomolecules including carbon-based NPs, metal-based NPs, and proteins/peptides. Those results not only provide profound knowledge for evaluating the impacts of dendrimers on environmental and biological systems but also facilitate designing next-generation functional polymeric nanomaterials. The dissertation is organized as following. Chapter 1 provides an overview of current progresses on dendrimer studies, where methodology of Discrete Molecular Dynamics (DMD), my major research tool, is also introduced. Two directions of utilizing dendrimers will be discussed in following chapters. Chapter 2 will focus on environmental applications of dendrimers, where two back-to-back studies are presented. I will start from describing some interesting observations from experiments i.e. dendrimers dispersed model oil molecules. Then, I will reveal why surface chemistries of dendrimers lead to different remediation efficiencies by computational modelings. Finally, I will demonstrate different scenarios of dendrimer-small molecules association. Chapter 3 is centered on dendrimers in the biomedical applications including two subtopics. In the first topic, we will discuss dendrimers as surfactants that modulating the interactions between proteins and NPs. Some fundamental concepts regarding to NPs-Protein interactions such as NP-protein corona are also explained. In the following topic, I will look into amyloid protein aggregation mediated by dendrimers, which is of high expectations for combating amyloidogenic-related diseases. Chapter 4 concludes the whole dissertation. It also briefly introduces my ongoing projects and future research directions about dendrimers. This dissertation has presented a systematic study of dendrimers in environmental and biomedical applications which might provide valuable information for future dendrimer design thus benefit the nanobiotechnology