Surface Activity of Poly(ethylene glycol)-Coated Silver Nanoparticles in the Presence of a Lipid Monolayer

We have investigated the surface activity of poly(ethylene glycol) (PEG)-coated silver nanoparticles (Ag-PEG) in the presence or absence of lipid monolayers comprised of monounsaturated dioleoylphosphocholine and dioleoylphosphoglycerol (DOPC/DOPG; 1:1 mol ratio). Dynamic measurements of surface pressure demonstrated that Ag-PEG were surface-active at the air/water interface. Surface excess concentrations suggested that at high Ag-PEG subphase concentrations, Ag-PEG assembled as densely packed monolayers in the presence and absence of a lipid monolayer. The presence of a lipid monolayer led to only a slight decrease in the excess surface concentration of Ag-PEG. Surface pressure–area isotherms showed that in the absence of lipids Ag-PEG increased the surface pressure up to 45 mN m–1 upon compression before the Ag-PEG surface layer collapsed. Our results suggest that surface activity of Ag-PEG was due to hydrophobic interactions imparted by a combination of the amphiphilic polymer coating and the hydrophobic dodecanethiol ligands bound to the Ag-PEG surface. With lipid present, Ag-PEG + lipid surface pressure–area (π–A) isotherms reflected Ag-PEG incorporation within the lipid monolayers. At high Ag-PEG concentrations, the π–A isotherms of the Ag-PEG + lipid films closely resembled that of Ag-PEG alone with a minimal contribution from the lipids present. Analysis of the subphase silver (Ag) and phosphorus (P) concentrations revealed that most of the adsorbed material remained at the air/lipid/water interface and was not forced into the aqueous subphase upon compression, confirming the presence of a composite Ag-PEG + lipid film. While interactions between “water-soluble” nanoparticles and lipids are often considered to be dominated by electrostatic interactions, these results provide further evidence that the amphiphilic character of a nanoparticle coating can also play a significant role

Psychometric evaluation of the Persian Internet Disorder Scale among adolescents

Background and aims: Given the growing epidemiological research interest concerning Internet addiction, brief instruments with a robust theoretical basis are warranted. The Internet Disorder Scale (IDS-15) is one such instrument that can be used to quickly assess the Internet addiction in an individual. However, only two language versions of the IDS-15 have been developed. This study translated the IDS-15 into Persian and examined its psychometric properties using comprehensive psychometric testing. Methods: After ensuring the linguistic validity of the Persian IDS-15, 1,272 adolescents (mean age = 15.53 years; 728 males) completed the IDS-15, Depression Anxiety Stress Scale (DASS), Internet Gaming Disorder Scale – Short Form (IGDS9-SF), and the Bergen Social Media Addiction Scale (BSMAS). Confirmatory factor analysis (CFA), Rasch models, regression analysis, and latent profile analysis (LPA) were carried out to test the psychometric properties of the Persian IDS-15. Results: Both CFA and Rasch supported the construct validity of the Persian IDS-15. Multigroup analysis in CFA and differential item functioning in Rasch indicated that male and female adolescents interpreted the IDS-15 items similarly. Regression analysis showed that the IDS-15 correlated with IGDS9-SF and BSMAS (ΔR2 = .12 and .36, respectively) is stronger than the DASS (ΔR2 = .03–.05). LPA based on IDS-15 suggests three subgroups for the sample. Significant differences in depression, anxiety, IGDS9-SF, and BSMAS were found among the three LPA subgroups. Conclusion: The Persian IDS-15 has robust psychometric properties as evidenced by both classical test theory and Rasch analysis

Information Theory-based Evolution of Neural Networks for Side-channel Analysis

Profiled side-channel analysis (SCA) leverages leakage from cryptographic implementations to extract the secret key. When combined with advanced methods in neural networks (NNs), profiled SCA can successfully attack even those cryptocores assumed to be protected against SCA. Despite the rise in the number of studies devoted to NN-based SCA, a range of questions has remained unanswered, namely: how to choose an NN with an adequate configuration, how to tune the NN’s hyperparameters, when to stop the training, etc. Our proposed approach, “InfoNEAT,” tackles these issues in a natural way. InfoNEAT relies on the concept of neural structure search, enhanced by information-theoretic metrics to guide the evolution, halt it with novel stopping criteria, and improve time-complexity and memory footprint. The performance of InfoNEAT is evaluated by applying it to publicly available datasets composed of real side-channel measurements. In addition to the considerable advantages regarding the automated configuration of NNs, InfoNEAT demonstrates significant improvements over other approaches for effective key recovery in terms of the number of epochs (e.g.,x6 faster) and the number of attack traces compared to both MLPs and CNNs (e.g., up to 1000s fewer traces to break a device) as well as a reduction in the number of trainable parameters compared to MLPs (e.g., by the factor of up to 32). Furthermore, through experiments, it is demonstrated that InfoNEAT’s models are robust against noise and desynchronization in traces

Preparation, Modeling, and Optimization of Mechanical Properties of Epoxy/H I PN/Silica Hybrid Nanocomposite Using Combination of Central Composite Design and Genetic Algorithm. Part 2. Studies on Flexural, Compression, and Impact Strength

In spite of good tensile strength of epoxy resins, they have brittle nature and show poor resistance to crack propagation. In view of enhancing mechanical strength and fracture toughness of epoxy-based nanocomposite simultaneously, a new combination of thermoplastic and particulate nanofiller is used as a modifier. Here, the obtained ternary epoxy-based nanocomposite includes high impact polystyrene (HIPS) as thermoplastic and silica nanoparticles as its particulate phases. Flexural, compression and impact were the three different mechanical tests investigated, in order to achieve higher strength without attenuating other desired mechanical properties. Central composite design (CCD) is employed to present mathematical models to predict mechanical behaviors of epoxy/HIPS/silica nanocomposite as a function of physical factors. The effective parameters investigated were HIPS, SiO₂ and hardener contents. Based on mathematical functions obtained from CCD model, the genetic algorithm – as one of the most powerful optimization tools – is applied to find the optimum values of mentioned mechanical properties. We have found that a combination of HIPS and silica nanoparticles significantly increase compressive and impact strengths of epoxy resin up to 57 and 421%, respectively. Although flexural strength did not change positively, the elongation at break for flexural one increased up to 144%. Finally, the morphology of fracture surface was studied by energy-dispersive X-ray spectroscopy and scanning electron microscopy.Несмотря на то что эпоксидные смолы обладают высоким пределом прочности при растяжении, они хрупкие и характеризуются слабым сопротивлением развитию трещины. С целью улучшения механической прочности и вязкости разрушения эпоксидных нанокомпозитов в качестве модификатора использовали новый комбинированный термопластичный дисперсный нанонаполнитель. Полученный трехкомпонентный эпоксидный нанокомпозит содержит ударопрочный полистирол в виде термопластичных и кремнеземных наночастиц, представляющих его дисперсные фазы. Чтобы получить более высокие показатели прочности без воздействия на другие заданные механические показатели, проводили испытания на прочность при изгибе и сжатии и на ударную вязкость. Для представления математических моделей с целью прогнозирования механического поведения гибридного нанокомпозита в качестве функции физических факторов использовали центральный композиционный план. Исследовали содержание ударопрочного полистирола, кремнезема и упрочняющего элемента в нанокомпозите. На основе математических функций, полученных по модели центрального композиционного плана, для выведения оптимальных значений механических свойств использовали генетический алгоритм, являющийся одним из самых мощных средств оптимизации. Установлено, что сочетание наночастиц на основе ударопрочного полистирола и кремнезема значительно увеличивает сопротивление эпоксидной смолы сжатию и удару на 57 и 421% соответственно. При сопротивлении изгибу положительных изменений не наблюдается, удлинение при изгибном разрыве увеличивается до 144%. С помощью энергодисперсионного рентгеновского излучения и сканирующей электронной микроскопии проведено исследование морфологии поверхности разрушения.Незважаючи на те що епоксидні смоли мають хорошу границю міцності при розтязі, вони крихкі і характеризуються слабким опором розвитку тріщини. Із метою покращання механічної міцності і в’язкості руйнування епоксидних нанокомпозитів як модифікатор використовували новий комбінований термопластичний дисперсний наповнювач. До складу отриманого трикомпонентного епоксидного нанокомпозита входить удароміцний полістирол у вигляді термопластичних і кремнеземних наночастинок, що являють собою його дисперсні фази. Щоб отримати більш високі показники міцності без впливу на інші задані механічні показники, проводили випробування на міцність при згині і стиску та на ударну в’язкість. Для представлення математичних моделей з метою прогнозування механічної поведінки гібридного нанокомпозита як функцію фізичних чинників використали центральний композиційний план. Досліджували вміст удароміцного полістиролу, кремнезему і зміцнювального елемента в нанокомпозиті. На основі математичних функцій, отриманих за моделлю центрального композиційного плану, для виведення оптимальних значень механічних властивостей використовували генетичний алгоритм, що є одним із найміцніших засобів оптимізації. Установлено, що поєднання наночастинок на основі удароміцного полістиролу і кремнезему збільшує опір епоксидної смоли стиску на 57%, удару – на 421%. У той же час позитивних змін при опорі згину не відмічається, видовження за згинального розриву збільшується до 144%. Проведено дослідження морфології поверхні руйнування за допомогою енергодисперсійного випромінювання і сканувальної електронної мікроскопії

Biological Evaluation of a Novel Tissue Engineering Scaffold of Layered Double Hydroxides (LDHs)

Bone Tissue Engineering (BTE) Composed of Three Main Parts: Scaffold, Cells and Signaling Factors. Several Materials and Composites Are Suggested as a Scaffold for BTE. Biocompatibility is One of the Most Important Property of a BTE Scaffold. in This Work Synthesis of a Novel Nanocomposite Including Layered Double Hydroxides (LDH) and Gelatin is Carried Out and its Biological Properties Were Studied. the Co-Precipitation (PH=11) Method Was Used to Prepare the LDH Powder, using Calcium Nitrate, Magesium Nitrate and Aluminum Nitrate Salts as Starting Materials. the Resulted Precipitates Were Dried. X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) Analyses Were Used to Characterize the Synthesized Powders. the Results Demonstrated the Presence of Nanocrystals of Ca-LDH and Mg-LDH as Hexagonal and Layered Morphology. the Obtained Powders Were Composed to Gelatin Via Solvent Casting Method Then Freez Dried. the Scaffold Was Prepared Via Membrane Lamination Method from the Resulted Layers that Linked Together with Gelatin as Binder. in Order to Investigate the Scaffold Cytotoxicity MTT Assay Was Done with a Osteosarcoma Cell Line. No Toxic Response Was Observed in Specimens. as a Major Result, It Was Demonstrated that the Specimen Showed a Significant Cellular Response. Then Osteosarcoma Cells Were Cultured for 7-Day and 14-Day Extract of Powders. the Composites Osteoconductivity Was Investigate with Cells Alkaline Phosphatase Extraction. the Results Demonstrated that the Ca-LDH/gelatin Composite Scaffold Has a Good Potential for Bone Tissue Engineering Applications and Mg-LDH Specimen Has a Better Osteconductivity. © (2012) Trans Tech Publications

A Fourier Analysis Based Attack against Physically Unclonable Functions

Electronic payment systems have leveraged the advantages offered by the RFID technology, whose security is promised to be improved by applying the notion of Physically Unclonable Functions (PUFs). Along with the evolution of PUFs, numerous successful attacks against PUFs have been proposed in the literature. Among these are machine learning (ML) attacks, ranging from heuristic approaches to provable algorithms, that have attracted great attention. Our paper pursues this line of research by introducing a Fourier analysis based attack against PUFs. More specifically, this paper focuses on two main aspects of ML attacks, namely being provable and noise tolerant. In this regard, we prove that our attack is naturally integrated into a provable Probably Approximately Correct (PAC) model. Moreover, we show that our attacks against known PUF families are effective and applicable even in the presence of noise. Our proof relies heavily on the intrinsic properties of these PUF families, namely arbiter, Ring Oscillator (RO), and Bistable Ring (BR) PUF families. We believe that our new style of ML algorithms, which take advantage of the Fourier analysis principle, can offer better measures of PUF security

Mediated effects of insomnia, psychological distress and medication adherence in the association of eHealth literacy and cardiac events among Iranian older patients with heart failure: a longitudinal study

Background: Given the importance of improving health for patients with heart failure, the present study examined the temporal associations between eHealth literacy, insomnia, psychological distress, medication adherence, quality of life and cardiac events among older patients with heart failure. Methods: With a longitudinal design older patients with echocardiography verified heart failure (N=468; 50.4% New York Heart Association class II, mean age 69.3±7.3 years; 238 men) in need of cardiac care at seven Iranian university outpatient clinics went through clinical examinations and completed the following questionnaires at baseline: eHealth literacy scale (eHEALS, assessing eHealth literacy); 5-item medication adherence report scale (MARS-5, assessing medication adherence); Minnesota living with heart failure questionnaire (MLHFQ, assessing quality of life); insomnia severity index (ISI, assessing insomnia); and hospital anxiety and depression scale (HADS, assessing psychological distress). All the patients completed the ISI and HADS again 3 months later; and the MARS-5 6 months later. Also, their cardiac events were collected 18 months later. Three mediation models were then conducted. Results: eHealth literacy had direct and indirect effects (through insomnia and psychological distress) on medication adherence and quality of life. Moreover, eHealth literacy had protecting effects on cardiac events (hazard ratio (HR) 0.53; 95% confidence interval (CI) 0.37, 0.65) through the mediators of insomnia (HR 0.19; 95% CI 0.15, 0.26), psychological distress (HR 0.08; 95% CI 0.05, 0.12) and medication adherence (HR 0.05; 95% CI 0.04, 0.08). Conclusion: As eHealth literacy was a protector for patients with heart failure, healthcare providers may plan effective programmes to improve eHealth literacy for the population. Additional benefits of improving eHealth literacy in heart failure may be decreased insomnia and psychological distress, improved quality of life, as well as decreased cardiovascular events

The study of cyst formation in bisexual strains of A. urmiana, A. franciscana and parthenogenetic strians of A. pakistan, A. turkmenistan in laboratory conditions

The study was conducted to achieve growth, survival and reproductive characteristics of four Artemia populations (A.urmiana , A.franciscana , Pakistan strain and Turkmanestan strain). In this study, The strains were cultured under the same and static environment in laboratory condition. All cysts strains were hatched using the standard methods and the nauplii from the populations were cultured in laboratory condition using 80 g/L salinity, 25±1ºC with photoperiod (12L:12D) and Dunalliella tertiolecta were fed. The growth and survival of artemia were determined on days 8, 11, 14, 17 and 20 of culture. Randomly, The adult population were placed in 50 ml conical falcons and reproductive characteristics were determined. The results revealed that the survivorship A. franciscana had the highest survival (%99.8) and A. turkmanestan lowest survival (%92.1) The results revealed that the in growth rate while pakistanian strain had the highest growth rate(8554 micron). The results revealed that the reproductive characteristics in each population of species , the highest cyst production were observed in A. urmiana, A. franciscana and A. turkmanestan strains and the highest nauplii production was due to pakistanian strain. The highest production were observed in A. franciscana and lowest production were observed in turkmanestan strain

Algorithms for Automated Pointing of Cardiac Imaging Catheters

This paper presents a modified controller and expanded algorithms for automatically positioning cardiac ultrasound imaging catheters within the heart to improve treatment of cardiac arrhythmias such as atrial fibrillation. Presented here are a new method for controlling the position and orientation of a catheter, smoother and more accurate automated catheter motion, and initial results of image processing into clinically useful displays. Ultrasound imaging (intracardiac echo, or ICE) catheters are steered by four actuated degrees of freedom (DOF) to produce bi-directional bending in combination with handle rotation and translation. Closed form solutions for forward and inverse kinematics enable position control of the catheter tip. Additional kinematic calculations enable 1-DOF angular control of the imaging plane. The combination of positioning with imager rotation enables a wide range of visualization capabilities, such as recording a sequence of ultrasound images and reconstructing them into 3D or 4D volumes for diagnosis and treatment. The algorithms were validated with a robotic test bed and the resulting images were reconstructed into 3D volumes. This capability may improve the efficiency and effectiveness of intracardiac catheter interventions by allowing visualization of soft tissues or working instruments. The methods described here are applicable to any long thin tendon-driven tool (with single or bi-directional bending) requiring accurate tip position and orientation control.Engineering and Applied Science