Photocatalytic activity and radiation-attenuation ability of copper ions surface-doped dysprosium oxide

Journal of Materials Science: Materials in Electronics - Herein, Cu ions surface-doped Dy2O3 photocatalyst (Cu–Dy2O3) is synthesized utilizing hydrothermal technique to degrade methyl violet...     

Personalized saliency prediction using color spaces

Saliency is the ability of being important, noticeable or attention worthy. Finding salient regions in images has important applications in automatic image cropping, image compression and advertisements. The salient regions for an individual in an image changes according to their gender, race, culture, likes, dislikes and experiences. Universal Saliency Maps point out the overall general salient regions without any considerations of personal traits of the subject. Therefore, personalized saliency maps are required for better and more personalized predictions of salient regions. In this study, using the RGB (Red, Green, Blue), CYMK (Cyan, Yellow, Magenta, Key), HSV (Hue, Saturation, Value) and HSL (Hue, Saturation, Lightness) fixation patterns of individuals, we propose a Gradient Boosted Tree Regression model to extract personalized saliency map from the universal saliency map with an average accuracy of 80% (Area Under Curve Judd Metrics). We also put forth our discussion for why some images and subjects have better saliency map predictions than others.

     

pH-sensitive capsules as intracellular optical reporters for monitoring lysosomal pH changes upon stimulation

The concept of a long-term sensor for ion changes in the lysosome is presented. The sensor is made by layer-by-layer assembly of oppositely charged polyelectrolytes around ion-sensitive fluorophores, in this case for protons. The sensor is spontaneously incorporated by cells and resides over days in the lysosome. Intracellular changes of the concentration of protons upon cellular stimulation with pH-active agents are monitored by read-out of the sensor fluorescence at real time. With help of this sensor concept it is demonstrated that the different agents used (Monensin, Chloroquine, Bafilomycin A1, Amiloride) possessed different kinetics and mechanisms of action in affecting the intracellular pH values.     

Text Encryption Using Pell Sequence and Elliptic Curves with Provable Security

The demand for data security schemes has increased with the significant advancement in the field of computation and communication networks. We propose a novel three-step text encryption scheme that has provable security against computation attacks such as key attack and statistical attack. The proposed scheme is based on the Pell sequence and elliptic curves, where at the first step the plain text is diffused to get a meaningless plain text by applying a cyclic shift on the symbol set. In the second step, we hide the elements of the diffused plain text from the attackers. For this purpose, we use the Pell sequence, a weight function, and a binary sequence to encode each element of the diffused plain text into real numbers. The encoded diffused plain text is then confused by generating permutations over elliptic curves in the third step. We show that the proposed scheme has provable security against key sensitivity attack and statistical attacks. Furthermore, the proposed scheme is secure against key spacing attack, ciphertext only attack, and known-plaintext attack. Compared to some of the existing text encryption schemes, the proposed scheme is highly secure against modern cryptanalysis.     

A Comparative Approach for the Preparation and Physicochemical Characterization of Lecithin Liposomes Using Chloroform and Non‐Halogenated Solvents

Organic solvents used in various pharmaceutical preparations may be associated with chronic health effects, with special emphasis on halogenated solvents. Liposomes, lipid bilayer membrane carriers, have potential applications in targeted drug delivery systems. The non‐halogenated solvents, acetonitrile and ethanol, were used in comparison to commonly used chloroform. The effect of solvents and dispersion medium was demonstrated using physicochemical properties, stability studies and hemolytic activity. Increased sonication time showed decreased particle size in phosphate buffer saline and water medium. Vesicles prepared from all solvents exhibited better stability in phosphate saline buffer than water when evaluated by particle size and zeta potentials. Liposomes showed a positive zeta potential in buffer solution whereas liposomes in water showed negative zeta potential. In vitro hemolytic activity of liposomes was done with fresh human red blood cells. Results in buffer solution were in the range of 1–4 % which further proved this medium superior to pure water. The findings of this study are helpful in suggesting the formulation of thin films by less hazardous solvents in terms of the environmental integrity and human health.     

A study of fullerite ablation with energetic pulsed electrons

We report the ablation of fullerite films deposited on metallic substrates with 3 keV electron pulses generated in a specially designed pulsed discharge tube. During ablation the fragmented species were detected by emission spectroscopy. The emission spectra of C₂ and C₁^∗ (CII) provide the signatures of C₆₀ fragmentation. The vibrational temperature of the C₂ emitted from the ablated fullerite is ∼12,700 ± 1160 K compared with ∼18,230 ± 1150 K for the graphite sample under similar conditions. The fullerite films were produced by vacuum sublimation on Aluminum, Iron and Copper substrates and characterized by Atomic force microscope, X-ray diffraction; Raman and Fourier transform infrared spectroscopy. The comparisons of electron ablation of fullerite films with that of graphite show the similarities and differences of carbon bonding in the caged structure of C₆₀ with that of the planar graphene sheets of graphite.     

Evaluation of selenium in biological sample of arsenic exposed female skin lesions and skin cancer patients with related to non-exposed skin cancer patients

The antagonistic effects between selenium (Se) and arsenic (As) suggest that low Se status plays an important role in arsenism development. The objective of present study was to assess Se contents in biological samples of As exposed females have skin lesions and cancer with related to non-exposed skin cancer patients. The biological samples (blood and scalp hair) of As exposed group comprises, female skin cancer (ESC) patients admitted in cancer hospitals have skin lesions (ESL) and exposed referents have not both diseases (ER), belongs to As exposed area of Pakistan. For comparative purposes, age matched female skin cancerous patient (RP) and non-cancerous females (NER) belong to non-exposed areas were also selected. The As and Se in acid digests of biological samples were pre-concentrated by complexing with chelating agent (ammonium pyrrolidinedithiocarbamate), and resulted complexes were extracted into non-ionic extractant (Triton X-114), prior to analysis by electrothermal atomic absorption spectrometry. The enhancement factor of about 25 was obtained by pre-concentrating 10 mL of sample solutions. The accuracy of the optimized procedure was evaluated by using certified reference material (BCR 397) with certified values for Se and As and standard addition method at three concentration levels in real samples. No significant differences was observed (p > 0.05) when comparing the values obtained by the proposed method, added and certified values of both elements. The biological samples of ESC patients had 2-3 folds higher As and lower Se levels as compared to RP (p < 0.001). Understudied exposed referents have high level of As and lower Se contents as compared to referents subjects of non-exposed area (p < 0.01). The higher concentration of As and lower levels of Se in biological samples of cancerous patients are consisted with reported studies.     

Polyhexamethylene Biguanide Functionalized Cationic Silver Nanoparticles for Enhanced Antimicrobial Activity

ABSTRACT: Polyhexamethylene biguanide (PHMB), a broad spectrum disinfectant against many pathogens, was used as a stabilizing ligand for the synthesis of fairly uniform silver nanoparticles. The particles formed were characterized using UV-visible spectroscopy, FTIR, dynamic light scattering (DLS), electrophoretic mobility and TEM to measure their morphology and surface chemistry. PHMB-functionalized silver nanoparticles were then evaluated for their antimicrobial activity against a gram negative bacterial strain, E. coli. These silver nanoparticles were found to have about 100 times higher bacteriostatic and bactericidal activities, compared to the previous reports, due to the combined antibacterial effect of silver nanoparticles and PHMB. In addition to other applications, PHMB-functionalized silver nanoparticles would be extremely useful in textile industry due to the strong interaction of PHMB with cellulose fabrics.