Diffusivity of adatoms on plasma-exposed surfaces determined from the ionization energy approximation and ionic polarizability

Microscopic surface diffusivity theory based on atomic ionization energy concept is developed to explain the variations of the atomic and displacement polarizations with respect to the surface diffusion activation energy of adatoms in the process of self-assembly of quantum dots on plasma-exposed surfaces. These polarizations are derived classically, while the atomic polarization is quantized to obtain the microscopic atomic polarizability. The surface diffusivity equation is derived as a function of the ionization energy. The results of this work can be used to fine-tune the delivery rates of different adatoms onto nanostructure growth surfaces and optimize the low-temperature plasma based nanoscale synthesis processes.Comment: Published versio

Electron-conduction mechanism and specific heat above transition temperature in LaFeAsO and BaFe(2)As(2) superconductors

The ionization energy theory is used to calculate the evolution of the resistivity and specific heat curves with respect to different doping elements in the recently discovered superconducting Pnictide materials. Subsequently, the electron-conduction mechanism in the Pnictides above the structural transition temperature is explained unambiguously, which is also consistent with other strongly correlated matter, such as cuprates, manganites, titanates and magnetic semiconductors. Therefore, the superconductivity is not uniquely corresponds to the electronic properties above the structural transition temperature. Detailed prediction are given on these compounds for various doping elements, namely, La(Sm,Ce,Ba,Sr,Ca)FeAsO(F,Cl,Br) and Ba(Sr,Ca,K,Rb,Cs)Fe(2)As(2).Comment: Published online: J. Supercond. Nov. Magn. (2009

Microscopic ion fluxes in plasma-aided nanofabrication of ordered carbon nanotip structures

Three-dimensional topography of microscopic ion fluxes in the reactive hydrocarbon-based plasma-aided nanofabrication of ordered arrays of vertically aligned single-crystalline carbon nanotip microemitter structures is simulated by using a Monte Carlo technique. The individual ion trajectories are computed by integrating the ion equations of motion in the electrostatic field created by a biased nanostructured substrate. It is shown that the ion flux focusing onto carbon nanotips is more efficient under the conditions of low potential drop UsUs across the near-substrate plasma sheath. Under low-UsUs conditions, the ion current density onto the surface of individual nanotips is higher for higher-aspect-ratio nanotips and can exceed the mean ion current density onto the entire nanopattern in up to approximately five times. This effect becomes less pronounced with increasing the substrate bias, with the mean relative enhancement of the ion current density ξiξi not exceeding ∼ 1.7∼1.7. The value of ξiξi is higher in denser plasmas and behaves differently with the electron temperature TeTe depending on the substrate bias. When the substrate bias is low, ξiξi decreases with TeTe, with the opposite tendency under higher-UsUs conditions. The results are relevant to the plasma-enhanced chemical-vapor deposition of ordered large-area nanopatterns of vertically aligned carbon nanotips, nanofibers, and nanopyramidal microemitter structures for flat-panel display applications.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87355/2/064304_1.pd

Deterministic nanoassembly: Neutral or plasma route?

It is shown that, owing to selective delivery of ionic and neutral building blocks directly from the ionized gas phase and via surface migration, plasma environments offer a better deal of deterministic synthesis of ordered nanoassemblies compared to thermal chemical vapor deposition. The results of hybrid Monte Carlo (gas phase) and adatom self-organization (surface) simulation suggest that higher aspect ratios and better size and pattern uniformity of carbon nanotip microemitters can be achieved via the plasma route.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87817/2/033109_1.pd

Conformal Nanocarbon Coating of Alumina Nanocrystals for Biosensing and Bioimaging

A conformal coating technique with nanocarbon was developed to enhance the surface properties of alumina nanoparticles for bio-applications. The ultra-thin carbon layer induces new surface properties such as water dispersion, cytocompatibility and tuneable surface chemistry, while maintaining the optical properties of the core particle. The possibility of using these particles as agents for DNA sensing was demonstrated in a competitive assay. Additionally, the inherent fluorescence of the core alumina particles provided a unique platform for localization and monitoring of living organisms, allowing simultaneous cell monitoring and intra-cellular sensing. Nanoparticles were able to carry genes to the cells and release them in an environment where specific biomarkers were present.Comment: 11 pages, 5 figures, Supporting Informatio

Suppression of current fluctuations in a crossed E×BE×B field system for low-voltage plasma immersion treatment

Plasma transport in a hybrid dc vacuum arc plasma source for ion deposition and plasma immersion treatment is considered. It is found that external crossed electric and magnetic fields near the substrate can significantly reduce the relative amplitude of ion current fluctuations fI¯f at the substrate surface. In particular, fI¯f decreases with the applied magnetic field when the bias voltage exceeds 300 V300V, thus allowing one to reduce the deviations from the rated process parameters. This phenomenon can be attributed to an interaction between the metal-plasma jet from the arc source and the discharge plasma in the crossed fields.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87466/2/013301_1.pd

Nano Technology and Gas Plasma as Novel Therapeutic Strategies for Ovarian Cancer Oncotherapy

Ovarian cancer (OC) is associated with a high rate of resistance to most chemotherapy drugs and thus novel therapies are crucial to overcoming these obstacles. The technological advances in nanotechnology make it possible to adapt these approaches for the treatment of chemo-resistant OC. In parallel, it is also evident that this emerging technology plays crucial roles in other medical areas including wound healing, treatment of viral infection and applications in dentistry. With the advancement of nanotechnology, nano dependent therapies are attractive viable alternatives to conventional therapies for various diseases, especially cancers. Nanoparticles (NPs) are a suitable platform for cytotoxic agent delivery and aiding early diagnosis of disease, which can lead to improving outcomes for these patients. Gas plasma oncotherapy is an innovative modality and shows huge potentials in cancer treatment and may emerge as the fifth cancer treatment modality together with surgery, radiotherapy, chemotherapy, targeted therapy and immunotherapy. The combination of nanoparticle and gas plasma therapy could lead to the discovery of an alternative effective treatment approach in these resistant tumors leading to improvement of OC prognosis. Here, we highlighted the two novel modalities with known multiple biological targets and underlying mechanisms appropriate for their application in OC treatment. This chapter explores the utility of combination or multimodal of novel nanotherapeutic agents in the treatment of OC

Lung Cancer Oncotherapy through Novel Modalities: Gas Plasma and Nanoparticle Technologies

Cold atmospheric pressure plasma (CAP) is emerging as new healthcare technology and it has a high potential through physical and chemical effects for cancer treatment. Recently, CAP, plasma activated liquid (PAL), and nanomaterial have been significant advances in oncotherapy. Reactive oxygen-nitrogen species (RONS), electrical field, and other agents generated by CAP interact with cells and induce selective responses between the malignant and normal cells. Nanomedicine enhances therapeutic effectiveness and decreases the side effects of traditional treatments due to their target delivery and dispersion in tumor tissue. There are various nanocarriers (NCs) which based on their properties can be used for the delivery of different agents. The combination of gas plasma and nanomaterials technologies is a new multimodal treatment in cancer treatment, therefore, is expected that the conjunction of these technologies addresses many of the oncology challenges. This chapter provides a framework for current research of NC and gas plasma therapies for lung cancer. Herein, we focus on the application of gas plasmas and nanotechnology to drug and gene delivery and highlight several outcomes of its. The types and features of the mentioned therapeutics strategy as novel classes for treating lung cancer individually and synergistic were examined

Microplasmas for Advanced Materials and Devices

Microplasmas are low-temperature plasmas that feature microscale dimensions and a unique high-energy-density and a nonequilibrium reactive environment, which makes them promising for the fabrication of advanced nanomaterials and devices for diverse applications. Here, recent microplasma applications are examined, spanning from high-throughput, printing-technology-compatible synthesis of nanocrystalline particles of common materials types, to water purification and optoelectronic devices. Microplasmas combined with gaseous and/or liquid media at low temperatures and atmospheric pressure open new ways to form advanced functional materials and devices. Specific examples include gas-phase, substrate-free, plasma-liquid, and surface-supported synthesis of metallic, semiconducting, metal oxide, and carbon-based nanomaterials. Representative applications of microplasmas of particular importance to materials science and technology include light sources for multipurpose, efficient VUV/UV light sources for photochemical materials processing and spectroscopic materials analysis, surface disinfection, water purification, active electromagnetic devices based on artificial microplasma optical materials, and other devices and systems including the plasma transistor. The current limitations and future opportunities for microplasma applications in materials related fields are highlighted.</p