Finite Difference Time Domain Simulation of Active Cancellation of Radar Echoes

AbstractRadar evasion or Stealth is a technology most desirable among all the military research areas currently pursued. Research organisations have focused their attention on electronic stealth technology or cancellation of waves since it is feasible now due to the improvement of high end processing and fast electronic systems. In an attempt to increase our understanding of this field, we have analysed the phenomenon through computer aided simulation. In this paper, we have created an electromagnetic wave simulation platform and using finite difference time domain method, analysed a method of active cancellation. We have found results showing complete effectiveness of this method assured by the accuracy of FDTD method

Optoelectronically mismatched oligophenylethynyl-naphthalenediimide SHJ architectures

The objective of this study was to evaluate the possibility of photoinduced stack/rod electron transfer in surface “zipper” architectures composed of stacks of blue (B) naphthalenediimides (NDIs) along strings of oligophenylethynyl (OPE) rods. The synthesis and characterization of anionic and cationic multichromophoric OPE-B systems are reported. Absorption spectra suggest that in OPE-B systems, planarity and thus absorption and conductivity of the OPE can possibly be modulated by intramolecular stacking of the surrounding NDIs, although interfering contributions from aggregation remain to be differentiated. Among surface architectures constructed with OPE-B and POP-B systems by zipper and layer-by-layer (LBL) assembly, photocurrents generated by OPE-B zippers exhibit the best critical thickness and fill factors. These findings confirm the existence and functional relevance of topologically matching zipper architectures. In OPE-B zippers, OPEs generate much more photocurrent than the blue NDIs. Ultrafast electron transfer from OPEs to NDIs accounts for these photocurrents, providing wavelength-controlled access to rod–stack charge separation, and thus to formal supramolecular n/p-heterojunctions (SHJs). NDI excitation is not followed by the complementary hole transfer to the OPE rod. Scaffolds with higher HOMOs will be needed to integrate blue NDIs into SHJ photosystems

Excited-State Dynamics of Hybrid Multichromophoric Systems: Toward an Excitation Wavelength Control of the Charge Separation Pathways

The photophysical properties of two hybrid multichromophoric systems consisting of an oligophenylethynyl (OPE) scaffold decorated by 10 red or blue naphthalene diimides (NDIs) have been investigated using femtosecond spectroscopy. Ultrafast charge separation was observed with both red and blue systems. However, the nature of the charge-separated state and its lifetime were found to differ substantially. For the red system, electron transfer occurs from the OPE scaffold to an NDI unit, independently of whether the OPE or an NDI is initially excited. However, charge separation upon OPE excitation is about 10 times faster, and takes place with a 100 fs time constant. The average lifetime of the ensuing charge-separated state amounts to about 650 ps. Charge separation in the blue system depends on which of the OPE scaffold or an NDI is excited. In the first case, an electron is transferred from the OPE to an NDI and the hole subsequently shifts to another NDI unit, whereas in the second case symmetry-breaking charge separation between two NDI units occurs. Although the charges are located on two NDIs in both cases, different recombination dynamics are observed. This is explained by the location of the ionic NDI moieties that depends on the charge separation pathway, hence on the excitation wavelength. The very different dynamics observed with red and blue systems can be accounted for by the oxidation potentials of the respective NDIs that are higher and lower than that of the OPE scaffold. Because of this, the relative energies of the two charge-separated states (hole on the OPE or an NDI) are inverted

Mitochondrial Sirtuins: Their Role in Different Diseases

This review paper aims to provide a comprehensive understanding of the three mitochondrial sirtuins (SIRT3, SIRT4, and SIRT5). Investigating their structural features, enzymatic activities, target proteins, involvement in diverse illness situations, and the therapeutic modulators created for SIRT3 and SIRT5 are the study's goals. We conducted a thorough literature survey, focusing on works that discussed the biochemical and physiological roles of SIRT3, SIRT4, and SIRT5 in the mitochondria. We looked over relevant research papers, reviews, and databases to learn more about their molecular make-ups, enzyme activity, and substrates. Studies indicating their involvement in metabolic pathways, physiological processes, and disease correlations gained considerable attention. Deacetylase activity in SIRT3 affects the TCA cycle, fatty acid oxidation, and glycolysis; SIRT4 affects the amino acids and TCA cycle; and SIRT5's acyl modifications affect the urea cycle, ROS, and glucose oxidation. Therapeutic alternatives are available for both SIRT3 and SIRT5. The review paper emphasizes the crucial functions of SIRT3, SIRT4, and SIRT5 in mitochondrial metabolism and their implications in a variety of illness situations in its conclusion. With a better understanding of their roles and potential therapeutic regulation, metabolic disorders, and other associated diseases may be treated. Unlocking the full potential of mitochondrial sirtuins as therapeutic targets will require more research in this area

Environmental DNA analysis as an emerging non-destructive method for plant biodiversity monitoring: a review

Environmental DNA (eDNA) analysis has recently transformed and modernized biodiversity monitoring. The accurate detection, and to some extent quantification, of organisms (individuals/populations/communities) in environmental samples is galvanizing eDNA as a successful cost and time-efficient biomonitoring technique. Currently, eDNA’s application to plants remains more limited in implementation and scope compared to animals and microorganisms. Thus, this review evaluates the development of eDNA-based methods for (vascular) plants, comparing its performance and power of detection with that of traditional methods, to critically evaluate and advise best practices needed for innovating plant biomonitoring. Recent advancements, standardization, and field applications of eDNA-based methods have provided enough scope to utilize it in conservation biology for numerous organisms. eDNA also has considerable potential for plants, where successful detection of invasive, endangered and rare species, and community-level interpretations have provided proof-of-concept. Monitoring methods using eDNA were found to be equal or more effective than traditional methods, however species detection increased when both the methods were coupled. Additionally, eDNA methods were found to be effective in studying species interactions, community dynamics, and even effects of anthropogenic pressure. Currently, elimination of potential obstacles (e.g., lack of relevant DNA reference libraries for plants) and the development of user-friendly protocols would greatly contribute to comprehensive eDNA-based plant monitoring programs. This is particularly needed in the data-depauperate tropics and for some less-concern plant groups. We further advocate it may be valuable to couple traditional methods with eDNA approaches, as the former is often cheaper and methodologically more straightforward, while the latter offers a non-destructive approach with the ability to identify plants in situations where morphological identification is difficult or impossible. Furthermore, in order to make a global platform for eDNA, governmental and academic-industrial collaborations are essential to make eDNA surveys a broadly adopted and implemented, rapid, cost-effective, and non-invasive plant monitoring approach

Artificial tongues and leaves

The objective with synthetic multifunctional nanoarchitecture is to create large suprastructures with interesting functions. For this purpose, lipid bilayer membranes or conducting surfaces have been used as platforms and rigid-rod molecules as shape-persistent scaffolds. Examples for functions obtained by this approach include pores that can act as multicomponent sensors in complex matrices or rigid-rod π-stack architecture for artificial photosynthesis and photovoltaic

Capra cartilage-derived peptide delivery via carbon nano-dots for cartilage regeneration

Targeted delivery of site-specific therapeutic agents is an effective strategy for osteoarthritis treatment. The lack of blood vessels in cartilage makes it difficult to deliver therapeutic agents like peptides to the defect area. Therefore, nucleus-targeting zwitterionic carbon nano-dots (CDs) have immense potential as a delivery vehicle for effective peptide delivery to the cytoplasm as well as nucleus. In the present study, nucleus-targeting zwitterionic CDs have been synthesized as delivery vehicle for peptides while also working as nano-agents towards optical monitoring of cartilage healing. The functional groups of zwitterion CDs were introduced by a single-step microwave assisted oxidation procedure followed by COL II peptide conjugation derived from Capra auricular cartilage through NHS/EDC coupling. The peptide-conjugated CDs (PCDs) allows cytoplasmic uptake within a short period of time (∼30 m) followed by translocation to nucleus after ∼24 h. Moreover, multicolor fluorescence of PCDs improves (blue, green, and read channel) its sensitivity as an optical code providing a compelling solution towards enhanced non-invasive tracking system with multifunctional properties. The PCDs-based delivery system developed in this study has exhibited superior ability to induce ex-vivo chondrogenic differentiation of ADMSCs as compared to bare CDs. For assessment of cartilage regeneration potential, pluronic F-127 based PCDs hydrogel was injected to rabbit auricular cartilage defects and potential healing was observed after 60 days. Therefore, the results confirm that PCDs could be an ideal alternate for multimodal therapeutic agents

Optoelectronic finetuning of supramolecular n/p-heterojunction Photosystems

Harvesting solar energy into chemical energy is a major challenge for scientists. So far conjugated polymer solar cells device placed a bench mark in organic solar cell research domain. But their photovoltaic performances stops after 5% efficiency due to inhomogeneous nanoscale morphology of donors and acceptors. Thus, supramolecular chemist wants to improve their photovoltaic performance by constructing an ordered, oriented and high hierarchical architecture on solid surface. Matile and co-workers introduced a high hierarchical network, called zipper assembly. Dream zipper assembly will be “panchromatic zipper assembly” which can absorb solar illumination AM 1.5. But it is still not clear whether blue NN-NDI chromophore can integrate into zipper assembly or not. To tackle this problem, we have synthesized NN-NDI-OPE hybrids. These molecules are subjected to zipper assembly formation. But it generates little photocurrent due-to energy mismatch between n-transporting NDI and p-transporting OPE. Whereas FF value showed a high hierarchical network formed in NN-NDI-OPE zipper assembly. Thus to achieve an optoelectronically matched zipper assembly we have finely tuned p-transporting channel. Oligothiophene (OT) is considered first as our next optoelectronic finely tuned p-transporter. OTs are widely used in polymer solar cell. There is no literature available where chromophores are installed in advance to construct solar cell. Thus we have synthesized NN-NDI-OT hybrids