CPA-induced Hz to THz broadband absorber with switchable perfect absorption between radio-microwave and THz frequency spectrum.

The coherent perfect absorption (CPA) occurring in the graphene sheet suspended in air can be utilized to develop an ultrathin, ultra-broadband absorber working in the frequency range from a few hertz (Hz) to terahertz (THz) with perfect absorption. A graphene sheet is studied to induce the CPA to cover radio, microwave and lower THz frequency ranges. A graphene resonator able to provide the surface plasmon resonance (SPR) is combined with the graphene sheet to provide CPA at either side of a thin dielectric layer forms metamaterial structure with the cavity and enhances the absorption bandwidth in the THz region by creating a resonance near quasi-CPA frequency. A dielectric silicon resonator is embedded in the structure, which creates dipolar resonances between the resonances obtained by the formed cavity between the graphene sheet and resonator. This enhances the absorption level in the THz region. The absorption bandwidth is further enhanced to 7 THz by including a graphene disc at the top of the silicon resonator. Thus, the multiple multi-order resonances occurring in the silicon dielectric and SPR of graphene resonators are merged with the phenomena of CPA occurring in the graphene sheets to extend the CPA bandwidth in the THz regime. The doping level of graphene or its tunable Fermi energy based on the applied DC electric field provides the tunability in the total obtained absorption bandwidth. The symmetric structure provides polarization-insensitive behavior with an allowed incident angle of more than 45° with more than 90% absorption.

Do all roads lead to the Rome? The glycation perspective!

Oxidative, carbonyl, and glycative stress have gained substantial attention recently for their alleged influence on cancer progression. Oxidative stress can trigger variable transcription factors, such as nuclear factor erythroid-2-related factor (Nrf2), nuclear factor kappa B (NF-κB), protein-53 (p-53), activating protein-1 (AP-1), hypoxia-inducible factor-1α (HIF-1α), ß-catenin/Wnt and peroxisome proliferator-activated receptor-γ (PPAR-γ). Activated transcription factors can lead to approximately 500 different alterations in gene expression, and can alter expression patterns of inflammatory cytokines, growth factors, regulatory cell cycle molecules, and anti-inflammatory molecules. These alterations of gene expression can induce a normal cell to become a tumor cell. Glycative stress resulting from advanced glycation end products (AGEs) and reactive dicarbonyls can significantly affect cancer progression. AGEs are fashioned from the multifaceted chemical reaction of reducing sugars with a compound containing an amino group. AGEs bind to and trigger the receptor for AGEs (RAGE) through AGE-RAGE interaction, which is a major modulator of inflammation allied tumors. Dicarbonyls like, GO (glyoxal), MG (methylglyoxal) and 3-DG (3-deoxyglucosone) fashioned throughout lipid peroxidation, glycolysis, and protein degradation are viewed as key precursors of AGEs. These dicarbonyls lead to the carbonyl stress in living organisms, possibly resulting in carbonyl impairment of proteins, carbohydrates, DNA, and lipoproteins. The damage caused by carbonyls results in numerous lesions, some of which are involved in cancer pathogenesis. In this review, the effects of oxidative, carbonyl and glycative stress on cancer initiation and progression are thoroughly discussed, including probable signaling pathways and the effects on tumorigenesis.

Altering the Multimodal Resonance in Ultrathin Silicon Ring for Tunable THz Biosensing.

A technique is implemented for altering the multimodal resonance generated in an ultrathin silicon ring resonator-based terahertz (THz) absorber. The absorber provides the dual-band resonance with the excitation of magnetic and electric dipole in the lower and upper band, respectively. The field of magnetic and electric dipoles is altered using a non-resonant graphene ring placed in the center of the generated dipolar arrangement and the tunability and perfect absorption is achieved. A circuit model is prepared using transmission line method and absorber operation is verified. The proposed absorber can be utilized as a biosensor for the detection of malaria virus and glucose percentage in water. The sensor offers highest sensitivity as 0.29 and 0.27 THz per thickness unit change and quality factor as 117.53 and 245 in the lower and upper band, respectively during the sensing of analyte thickness. Also, it offers the sensitivity as 0.20 and 0.10 THz per refractive index unit change and quality factor as 105.28 and 211.84 in the lower and upper band, respectively during refractive index sensing. Moreover, the structure remains insensitive to polarization angle of the incident electromagnetic wave.

Tumor-targeted Drug Delivery by Nanocomposites.

BACKGROUND: Tumor-targeted delivery by nanoparticles is a great achievement towards the use of highly effective drug at very low doses. The conventional development of tumor-targeted delivery by nanoparticles is based on enhanced permeability and retention (EPR) effect and endocytosis based on receptor-mediated are very demanding due to the biological and natural complications of tumors as well as the restrictions on the design of the accurate nanoparticle delivery systems. METHODS: Different tumor environment stimuli are responsible for triggered multistage drug delivery systems (MSDDS) for tumor therapy and imaging. Physicochemical properties, such as size, hydrophobicity and potential transform by MSDDS because of the physiological blood circulation different, intracellular tumor environment. This system accomplishes tumor penetration, cellular uptake improved, discharge of drugs on accurate time, and endosomal discharge. RESULTS: Maximum drug delivery by MSDDS mechanism to target therapeutic cells and also tumor tissues and sub cellular organism. Poorly soluble compounds and bioavailability issues have been faced by pharmaceutical industries, which are resolved by nanoparticle formulation. CONCLUSION: In our review, we illustrate different types of triggered moods and stimuli of the tumor environment, which help in smart multistage drug delivery systems by nanoparticles, basically a multi-stimuli sensitive delivery system, and elaborate their function, effects, and diagnosis.