In 2004, the first American Heart Association scientific statement on “Air Pollution and Cardiovascular Disease” concluded that exposure to particulate matter (PM) air pollution contributes to card...

https://cdr.lib.unc.edu/downloads/p2676x621

Particulate Matter Air Pollution and Cardiovascular Disease An Update to the Scientific Statement From the American Heart Association

We provide a broad review of fundamental electronic properties of two-dimensional graphene with the emphasis on density and temperature dependent carrier transport in doped or gated graphene structures. A salient feature of our review is a critical comparison between carrier transport in graphene and in two-dimensional semiconductor systems (e.g. heterostructures, quantum wells, inversion layers) so that the unique features of graphene electronic properties arising from its gap- less, massless, chiral Dirac spectrum are highlighted. Experiment and theory as well as quantum and semi-classical transport are discussed in a synergistic manner in order to provide a unified and comprehensive perspective. Although the emphasis of the review is on those aspects of graphene transport where reasonable consensus exists in the literature, open questions are discussed as well. Various physical mechanisms controlling transport are described in depth including long- range charged impurity scattering, screening, short-range defect scattering, phonon scattering, many-body effects, Klein tunneling, minimum conductivity at the Dirac point, electron-hole puddle formation, p-n junctions, localization, percolation, quantum-classical crossover, midgap states, quantum Hall effects, and other phenomena.

/pdf/electronic-transport-in-two-dimensional-graphene-32oou47sy4.pdf

Electronic transport in two-dimensional graphene

This review is presented as a common foundation for scientists interested in nanoparticles, their origin, activity, and biological toxicity. It is written with the goal of rationalizing and informing public health concerns related to this sometimes-strange new science of “nano,” while raising awareness of nanomaterials’ toxicity among scientists and manufacturers handling them. We show that humans have always been exposed to tiny particles via dust storms, volcanic ash, and other natural processes, and that our bodily systems are well adapted to protect us from these potentially harmful intruders. The reticuloendothelial system, in particular, actively neutralizes and eliminates foreign matter in the body, including viruses and nonbiological particles. Particles originating from human activities have existed for millennia, e.g., smoke from combustion and lint from garments, but the recent development of industry and combustion-based engine transportation has profoundly increased anthropogenic particulate pollution. Significantly, technological advancement has also changed the character of particulate pollution, increasing the proportion of nanometer-sized particles-“nanoparticles”-and expanding the variety of chemical compositions. Recent epidemiological studies have shown a strong correlation between particulate air pollution levels, respiratory and cardiovascular diseases, various cancers, and mortality. Adverse effects of nanoparticles on human health depend on individual factors such as genetics and existing disease, as well as exposure, and nanoparticle chemistry, size, shape, agglomeration state, and electromagnetic properties. Animal and human studies show that inhaled nanoparticles are less efficiently removed than larger particles by the macrophage clearance mechanisms in the lungs, causing lung damage, and that nanoparticles can translocate through the circulatory, lymphatic, and nervous systems to many tissues and organs, including the brain. The key to understanding the toxicity of nanoparticles is that their minute size, smaller than cells and cellular organelles, allows them to penetrate these basic biological structures, disrupting their normal function. Examples of toxic effects include tissue inflammation, and altered cellular redox balance toward oxidation, causing abnormal function or cell death. The manipulation of matter at the scale of atoms, “nanotechnology,” is creating many new materials with characteristics not always easily predicted from current knowledge. Within the nearly limitless diversity of these materials, some happen to be toxic to biological systems, others are relatively benign, while others confer health benefits. Some of these materials have desirable characteristics for industrial applications, as nanostructured materials often exhibit beneficial properties, from UV absorbance in sunscreen to oil-less lubrication of motors. A rational science-based approach is needed to minimize harm caused by these materials, while supporting continued study and appropriate industrial development. As current knowledge of the toxicology of “bulk” materials may not suffice in reliably predicting toxic forms of nanoparticles, ongoing and expanded study of “nanotoxicity” will be necessary. For nanotechnologies with clearly associated health risks, intelligent design of materials and devices is needed to derive the benefits of these new technologies while limiting adverse health impacts. Human exposure to toxic nanoparticles can be reduced through identifying creation-exposure pathways of toxins, a study that may someday soon unravel the mysteries of diseases such as Parkinson’s and Alzheimer’s. Reduction in fossil fuel combustion would have a large impact on global human exposure to nanoparticles, as would limiting deforestation and desertification. While nanotoxicity is a relatively new concept to science, this review reveals the result of life’s long history of evolution in the presence of nanoparticles, and how the human body, in particular, has adapted to defend itself against nanoparticulate intruders.

https://avs.scitation.org/doi/pdf/10.1116/1.2815690

Nanomaterials and nanoparticles: Sources and toxicity

http://ltl.tkk.fi/ice/Kevo/noisereview.pdf

Shot noise in mesoscopic conductors

Bio-nanocomposites for food packaging applications

Preface Introduction 1. Foundations 2. Electrons and phonons in crystals 3. Heterostructures 4. Quantum wells and low-dimensional systems 5. Tunnelling transport 6. Electric and magnetic fields 7. Approximate methods 8. Scattering rates: the Golden Rule 9. The two-dimensional electron gas 10. Optical properties of quantum wells Appendix 1. Table of physical constants Appendix 2. Properties of important semiconductors Appendix 3. Properties of GaAs-AlAs alloys at room temperature Appendix 4. Hermite's equation: harmonic oscillator Appendix 5. Airy functions: triangular well Appendix 6. Kramers-Kronig relations and response functions Bibliography.

The physics of low-dimensional semiconductors : an introduction

The physics of low-dimensional semiconductors

Rationale: Increased exposure to particulate air pollution (PM10) is a risk factor for death and hospitalization with cardiovascular disease. It has been suggested that the nanoparticulate component of PM10 is capable of translocating into the circulation with the potential for direct effects on the vasculature.Objective: The study's aim was to determine the extent to which inhaled technetium-99m (99mTc)–labeled carbon nanoparticles (Technegas) were able to access the systemic circulation.Methods and Main Results: Ten healthy volunteers inhaled Technegas and blood samples were taken sequentially over the following 6 h. Technegas particles were 4–20 nm in diameter and aggregated to a median particle diameter of approximately 100 nm. Radioactivity was immediately detected in blood, with levels increasing over 60 min. Thin-layer chromatography of whole blood identified a species that moved with the solvent front, corresponding to unbound 99mTc-pertechnetate, which was excreted in urine. There was no evidence...

/pdf/do-inhaled-carbon-nanoparticles-translocate-directly-into-143g5xg0ek.pdf

Do inhaled carbon nanoparticles translocate directly into the circulation in humans

In this paper, we present a detailed simulation study of the influence of quantum mechanical effects in the inversion layer on random dopant induced threshold voltage fluctuations and lowering in sub-100 mn MOSFETs. The simulations have been performed using a three-dimensional (3-D) implementation of the density gradient (DG) formalism incorporated in our established 3-D atomistic simulation approach. This results in a self-consistent 3-D quantum mechanical picture, which implies not only the vertical inversion layer quantization but also the lateral confinement effects related to current filamentation in the "valleys" of the random potential fluctuations. We have shown that the net result of including quantum mechanical effects, while considering statistical dopant fluctuations, is an increase in both threshold voltage fluctuations and lowering. At the same time, the random dopant induced threshold voltage lowering partially compensates for the quantum mechanical threshold voltage shift in aggressively scaled MOSFETs with ultrathin gate oxides.

/pdf/increase-in-the-random-dopant-induced-threshold-fluctuations-4ijlq78lub.pdf

Increase in the random dopant induced threshold fluctuations and lowering in sub-100 nm MOSFETs due to quantum effects: a 3-D density-gradient simulation study

Ionized donors in a doped heterostructure have random positions, which gives rise to a random potential with long-ranged fluctuations. This has a small effect on fast electrons, allowing high mobilities in two-dimensional electron gases, but becomes much more significant when the density of electrons is low. We have analysed the effect of this random potential using a semi-classical, self-consistent method to calculate the density of electrons. This includes a realistic potential from a patterned gate, and is followed by a quantum-mechanical calculation of the conductance.

John H. Davies

Papers

The physics of low-dimensional semiconductors : an introduction

The physics of low-dimensional semiconductors

Do inhaled carbon nanoparticles translocate directly into the circulation in humans

Increase in the random dopant induced threshold fluctuations and lowering in sub-100 nm MOSFETs due to quantum effects: a 3-D density-gradient simulation study

Potential Fluctuations in Heterostructure Devices