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Copyright of Revista Ciencia y Poder Aéreo is the property of Escuela de Postgrados de la Fuerza Aerea Colombiana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objectives: The main objective of the present investigation was to develop and compared conventional, chitosan-coated and electrosteric stealth liposomes of Rivastigmine Tartrate for the treatment of Alzheimer's Disease. Methods: The solvent evaporation method was employed to prepare liposomes and optimized by the Design of Experiment approach. The effect of various process parameters was investigated and optimized on for particle size and percentage entrapment efficiency. The compatibility studies were carried out using Fourier Transform Infrared Spectroscopy. The optimized formulations were also characterized by Transmission Electron Microscopy and Atomic Force Microscopy for their surface morphology and in vitro percentage drug release study by comparing it with a standard solution of Rivastigmine Tartrate. The compatibility of drug and excipient mixtures was confirmed by Fourier Transform Infrared Spectroscopy. Results: The optimized formulation of conventional, chitosan-coated, stealth liposome of Rivastigmine Tartrate showed vesicle size of 111.8, 153.3, 136.3 nm respectively and entrapment efficiency of 75.27±0.8 %, 80.33±0.4 % 78.2±0.2 respectively. Clear surface morphology was observed through surface morphological images. The in vitro drug release studies showed a significant difference in percentage cumulative drug release pattern of chitosan-coated and stealth liposomes (81±0.3 % and 76±1.2 %) when compared with the conventional liposomes (69±0.8 %), after 24 h. On subjecting it to stability studies, the liposome preparations did not show any significant changes in particle size and entrapment efficiency. Conclusion: The developed formulations (chitosan-coated and stealth liposomes) can deliver the active moiety on the target site for the treatment of AD. [ABSTRACT FROM AUTHOR]

The protein corona is a natural protein layer spontaneously formed around nanomaterials when exposed to biological media. This layer can alter the nanosystems' biological performance, particularly their tissue accumulation, cellular uptake, clearance by the immune system, toxicity, and even the release profile of their payloads. Hence, the characterization of this protein layer has become a critical step when developing a new nanomedicine. The modification of the nanosystem fate by the protein corona, systematically ignored in the vast majority of the nanotechnology-based research, may have contributed to the low in vitro/in vivo correlation. Actually, the protein corona of polymeric nanosystems has been scarcely studied in the literature, and most studies have been focused instead on metallic nanoparticles and liposomes. In this review, we analyzed the influence of the physicochemical properties and composition of the polymeric nanosystems on the protein layer deposited around them. In addition, we present some recommendations on how to perform the protein corona studies of polymeric nanoparticles, which, hopefully, will contribute to obtain more reliable and reproducible data in the future. [ABSTRACT FROM AUTHOR]

Random attacks that jointly minimize the amount of information acquired by the operator about the state of the grid and the probability of attack detection are presented. The attacks minimize the information acquired by the operator by minimizing the mutual information between the observations and the state variables describing the grid. Simultaneously, the attacker aims to minimize the probability of attack detection by minimizing the Kullback-Leibler (KL) divergence between the distribution when the attack is present and the distribution under normal operation. The resulting cost function is the weighted sum of the mutual information and the KL divergence mentioned above. The trade-off between the probability of attack detection and the reduction of mutual information is governed by the weighting parameter on the KL divergence term in the cost function. The probability of attack detection is evaluated as a function of the weighting parameter. A sufficient condition on the weighting parameter is given for achieving an arbitrarily small probability of attack detection. The attack performance is numerically assessed on the IEEE 14-Bus, 30-Bus, and 118-Bus test systems. [ABSTRACT FROM AUTHOR]

Microwave-absorbing materials play a significant role in various applications that involve the attenuation of electromagnetic radiation. This critical review article provides an overview of the progress made in the development and understanding of microwave-absorbing materials. The interaction between electromagnetic radiation and absorbing materials is explained, with a focus on phenomena such as multiple reflections, scattering, and polarizations. Additionally, types of losses that affect the performance of microwave absorbers are also discussed, including dielectric loss, conduction loss, relaxation loss, magnetic loss, and morphological loss. Each of these losses has different implications for the effectiveness of microwave absorbers. Further, a detailed review is presented on various types of microwave absorbing materials, including carbonaceous materials, conducting polymers, magnetic materials, metals and their composites, 2D materials (such as MXenes and 2D-transition metal dichalcogenides), biomass-derived materials, carbides, sulphides, phosphides, high entropy (HE) materials and metamaterials. The characteristics, advantages, and limitations of each material are examined. Overall, this review article highlights the progress achieved in the field of microwave-absorbing materials. It underlines the importance of optimizing different types of losses to enhance the performance of microwave absorbers. The review also recognizes the potential of emerging materials, such as 2D materials and high entropy materials, in further advancing microwave-absorbing properties. [Display omitted] • Overview of progress in microwave-absorbing materials. • Understanding interaction between electromagnetic radiation and absorbing materials. • Types of losses affecting microwave absorbers' performance. • Detailed review of various types of microwave-absorbing materials. • Importance of optimizing different types of losses for enhanced performance. [ABSTRACT FROM AUTHOR]

• This paper aims to measure the electromagnetic (EM) characteristics of 3D-printed radar absorbing structures (RASs) based on three-dimensional period pattern surface. • The metrology is validated using HFSS software, a 3D printer and a scanning free-space measurement. • It is crucial to employ specific measurement conditions for each surface shape and examine the distribution of EM characteristics across the entire specimen area. • The analysis and measurement techniques proposed can be applied to the design of 3D-printed RASs. This paper aims to assess the electromagnetic (EM) characteristics of 3D-printed radar absorbing structures (RASs) based on three-dimensional period pattern surface (3D PPS) within the X-band frequency range (8.2–12.4 GHz). The assessment is validated through HFSS software, a 3D printer (Markforged, X7), and a scanning free-space measurement (SFM) system. Firstly, the analysis indicates that the EM characteristics of RASs based on 3D PPS are impacted by impedance matching in the thickness direction and the scattering of EM waves at the edges. The utilization of Onyx (Chopped carbon fiber/Nylon) reveals variations in resonance frequencies and EM wave absorption performance contingent upon the surface shape. Furthermore, significant differences in the variations of EM characteristics are observed even for RASs with the same surface shape but different materials. Secondly, the measurement results of 3D-printed RAS specimens based on PPS using Onyx exhibit similar trends to the analysis results obtained with the SFM system. Ensuring precise measurement results requires specific measurement conditions tailored to each surface shape, along with an examination of the EM characteristic distribution across the entire specimen area. This is crucial due to variations in the size, number, and range of reflected EM waves in the time domain. The analysis and measurement techniques presented in this study hold applicability in designing 3D-printed RASs that demand high EM wave absorption performance, whether under normal or oblique incident EM waves. [ABSTRACT FROM AUTHOR]

The coating for cockpit glass is one of the important ways to realize aircraft stealth technology. The stealth characteristics of Nb-doped ITO(Indium Tin Oxides) coated glass is studied by using the RCS(Radar Cross Section) mean gain. A series of RCS darkroom tests are carried out for Nb-doped ITO coated glasses with different sheet resistance, and the electromagnetic scattering characteristics with different incident frequencies and polarization modes are analyzed. It is found that, when the sheet resistance increases, the electromagnetic scattering decreases, and the appropriate sheet resistance(less than 40 Ω/m2) is beneficial to realize the shape-stealth of cockpit, and its scattering characteristic is also close to the metal’s, the peak of specular scattering is narrow when the frequency is high.

Spyware is the most complex, obfuscated, and targeted class of malware, which has grown dramatically in recent years. Spyware is designed for secret, long-term, and persistent missions. This paper provides a novel method for detection, tracking, and confronting the stealth and obfuscated spyware and ransomware, including keyloggers, screen recorders, and blockers. The proposed method of this paper is based on a dynamic behavioral analysis through deep and transparent hooking of kernel-level routines. We used linear regression, JRIP, and J48 decision tree algorithms as a classifier to recognize three classes of malware. This paper presents the main architectural plan of an anti-spyware application to track spyware footprints in order to detect and force terminate running processes, eliminate executable files, and restrict network communications. The efficiency of the proposed method was evaluated from the viewpoint of accuracy in detecting real-world samples of spyware by ROC curve analysis and from the viewpoint of success rate to confront effectively with active spyware. Our proposed method was able to recognize spyware with an accuracy of about 93% and an error rate near 7%. In addition, the proposed system can disinfect an operating system from infection by spyware with a hit rate of about 82%.

Several liposome products have been approved for the treatment of cancer. In all of them, the active agents are encapsulated in the liposome water phase passively or by transmembrane ion gradients. An alternative approach in liposomal drug delivery consists of chemically modifying drugs to form lipophilic prodrugs with strong association to the liposomal bilayer. Based on this approach, we synthesized a mitomycin c-derived lipidic prodrug (MLP) which is entrapped in the bilayer of PEGylated liposomes (PL-MLP, Promitil®), and activated by thiolytic cleavage. PL-MLP is stable in plasma with thiolytic activation of MLP occurring exclusively in tissues and is more effective and less toxic than conventional chemotherapy in various tumor models. PL-MLP has completed phase I clinical development where it has shown a favorable safety profile and a 3-fold reduction in toxicity as compared to free mitomycin c. Clinical and pharmacokinetic studies in patients with advanced colo-rectal carcinoma have indicated a significant rate of disease stabilization (39%) in this chemo-refractory population and significant prolongation of median survival in patients attaining stable disease (13.9 months) versus progressive disease patients (6.35 months). The pharmacokinetics of MLP was typically stealth with long T½ (~1 day), slow clearance and small volume of distribution. Interestingly, a longer T½, and slower clearance were both correlated with disease stabilization and longer survival. This association of pharmacokinetic parameters with patient outcome suggests that arrest of tumor growth is related to the enhanced tumor localization of long-circulating liposomes and highlights the importance of personalized pharmacokinetic evaluation in the clinical use of nanomedicines. Another important area where PL-MLP may have an added value is in chemoradiotherapy, where it has shown a strong radiosensitizing effect in animal models based on a unique mechanism of enhanced prodrug activation and encouraging results in early human testing. Unlabelled Image [ABSTRACT FROM AUTHOR]

Novel long-range missiles, sensor technologies, and directed-energy weapons are rapidly disrupting the balance between offense and defense in modern warfare. It will probably become significantly more difficult to hide aircraft, ships, and vehicles on the battlefield as sensors improve and the cost premium for effective stealth increases. Hypersonic missiles threaten to make it more difficult to defend key assets using traditional means. However, sensor advances will aid both sides, and, if directed-energy weapons can be effectively developed and deployed, the trend could shift the other way, toward effective point defenses limited only by power and cooling. With multiple, potentially contradictory trends, the outcome for strategic stability remains extremely difficult to discern. [ABSTRACT FROM AUTHOR]

Copyright of Ordnance Industry Automation is the property of Editorial Board for Ordnance Industry Automation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Stealth technology is very important for the survival of military aircraft. A stealth aircraft structure has both electromagnetic and mechanical functions. Lightning can cause failure on both the points. In this study, we claim that the stealth structure should be evaluated nondestructively and electromagnetically, and we propose a method for full-field evaluations of both the functions. First, a radar absorbing structure was designed and fabricated with stealth capability in the X-band. The radar absorbing structure consisted of a carbon nanotube layer (glass/epoxy dispersed with multiwalled carbon nanotubes), a spacer layer (glass/epoxy) and a perfect electrical conductor layer. A lightning test was performed using an impulse current generator according to standard regulations. Then, nondestructive damage and electromagnetic performance evaluations were performed using a pulse-echo laser ultrasonic propagation imager and a scanning free-space measurement system, respectively. The results showed that neither structural damage nor changes in the electromagnetic properties were observed during the two evaluations. In general, the composites were severely damaged by lightning. However, it turned out that the radar absorbing structure with the carbon nanotube layer could prevent serious damage to stealth function as well as material damage owing to the high conductivity of the carbon nanotubes dispersed in its surface layer. [ABSTRACT FROM AUTHOR]

Stealth airborne systems are low observable platforms, which bring together technologies in the field of aerodynamics, electromagnetics, and material science. Radar absorbing materials/structures play a key role in the design of such stealth airborne platforms. In this paper, a radar absorber has been fabricated based on the design of a nonperiodic metallic patch coated with graphene. The simulation results of the novel design over an ultrawideband (1–60 GHz) yield good absorption (99.93%). With the constraint of fabrication facility, a small unit cell of the structure has been fabricated and measured. The measurement results show a good agreement with the simulation results. The absorption bandwidths, thickness, and weight of the structure are some of the key elements that were considered in the design model. It has been observed that the design allows the electric potential tuning by changing the Fermi energy of the graphene layer. The significant absorption of the proposed design in ultrawideband shows that it has potential applications in the RF stealth technology. [ABSTRACT FROM AUTHOR]

An experimental study was carried out on a laboratory-scale louvered conical infrared suppression (IRS) device to predict the air entrainment into it. A comparison has been made between the louvered conical, conical and the cylindrical IRS device based on the air entrainment ratio with increasing geometric ratio. A numerical study on the flow domain was also performed by solving the continuity and Navier-Stokes equations using the k-epsilon turbulence model. The air entrainment was compared with the experimental data and a good match was found. The results showed that the louvered conical IRS device outperforms the other two IRS devices significantly when the geometric ratio exceeds a value of 1.4. The mass entrainment of the ambient air was maximum when four louvered funnels at optimum overlap were used. Increasing or decreasing the number of funnels from this value lowers the air entrainment. In the analysis, it was also found that the nozzle protrusion adversely affects the air entrainment and hence for getting the highest entrainment, the nozzle was flush with the lower opening of the bottom most funnel. The funnel overlap also acts as an important parameter as far as the rate of air entrainment is concerned. The air entrainment through the IRS device was found to be maximum when the non-dimensional funnel overlap height ( H o v e r l a p / D n z ) was kept at 8. The mass entrainment rate was found to increase linearly with the nozzle exit Reynolds number in the range of parameters for which the study was undertaken. Image 1 • A New Infra-Red Suppression (IRS) device comprised of conical louvered funnels has been studied experimentally as well as numerically and has been compared with the other IRS devices. • After a geometric ratio of 1.4, the proposed IRS device outperforms the other IRS devices significantly for any number of funnels. • There exist an optimum number of funnels for the new IRS device to have highest mass entrainment of air. • The proposed IRS device gives maximum mass entrainment at an optimum nozzle protrusion height as well as at an optimum funnel overlap height. [ABSTRACT FROM AUTHOR]

Copyright of Electronic Components & Materials is the property of Electronic Components & Materials and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

New U.S.-DOD guiding instructions for 2019 JEST-R&D funded proposals, are now available, [1]. Past U.S.-decision "not to weaponize" JEST, has induced it to advance Anti-Gliding-Hypersonic-Scramjet-Threats, (GHST), [1-20]. This editorial updates previous ones, [21-31], mainly on RE-EDUCATING JET-ENGINE RESEARCHERS TO STAY RELEVANT, especially in JETONAUTIC-POST-STALL-FLIGHT, where AOOF fails, [32-84]. Since 11.06.2018, China has joined the US-Russian jet-engines-steering (JES) global-race by JES-F-22 v. JES-Su-35 and 57 & JES-10B, [73-74] v. THAAD, Arrow-3, David-Sling global network v. 6th-generation S500, Avangard and other systems, [85-86]. [ABSTRACT FROM AUTHOR]

• The quantitative measurement of the effect of water spray on mitigating the IR signature from the engine plume was conducted. • Higher injection pressure resulted in the formation of a denser water spray cloud, thereby increasing the attenuation effect on the IR signature. • The water spray cloud effectively attenuated the IR signature, with enhanced effectiveness observed at lower observation angles. In modern military aircraft, reducing the Infrared (IR) signature is critical for stealth. However, the IR signature from the engine plume is particularly challenging to address due to its link with engine operation and its unique, non-continuous characteristics. In this study, a novel approach using a water spray cloud to attenuate the IR signature from the engine plume was proposed, and it is experimentally verified by employing a micro-turbine engine. Six water nozzles generated the water spray cloud, and IR signature reduction was quantitatively measured using an IR spectrometer. Variations in water injection pressure and observation angles were used as experimental conditions. The results revealed that the IR signature was reduced with higher water injection pressure, attributed to the increased thickness of the water spray cloud. The IR signature from the engine plume was effectively attenuated by the water spray cloud in overall, with a more pronounced effect observed at lower observation angles due to the extended path within the cloud. The potential of water spray clouds for enhancing the IR stealth of military aircraft is underscored by this research. [ABSTRACT FROM AUTHOR]

Engineered nanomaterials hold promise for a wide range of applications in medicine. However, safe use of nanomaterials requires that interactions with biological systems, not least with the immune system, are understood. Do nanomaterials elicit novel or unexpected effects, or is it possible to predict immune responses to nanomaterials based on how the immune system handles pathogens? How does the bio-corona of adsorbed biomolecules influence subsequent immune interactions of nanomaterials? How does the grafting of polymers such as poly(ethylene glycol) onto nanomaterial surfaces impact on these interactions? Can ancient immune evasion or “stealth” strategies of pathogens inform the design of nanomaterials for biomedical applications? Can nanoparticles co-opt immune cells to target diseased tissues? The answers to these questions may prove useful for the development of nanomedicines.

Nanoparticles (NPs) have emerged as a powerful drug-delivery tool for cancer therapies to enhance the specificity of drug actions, while reducing the systemic side effects. Nonetheless, NPs interact massively with the surrounding physiological environments including plasma proteins upon administration into the bloodstream. Consequently, they are rapidly cleared from the blood circulation by the mononuclear phagocyte system (MPS) or complement system, resulting in a premature elimination that will cause the drug release at off-target sites. By grafting a stealth coating layer onto the surface of NPs, the blood circulation half-life of nanomaterials can be improved by escaping the recognition and clearance of the immune system. This review focuses on the basic concept underlying the stealth behavior of NPs by polymer coating, whereby the fundamental surface coating characteristics such as molecular weight, surface chain density as well as conformations of polymer chains are of utmost importance for efficient protection of NPs. In addition, the most commonly used stealth polymers such as poly(ethylene glycol) (PEG), poly(2-oxazoline) (POx), and poly(zwitterions) in developing long-circulating NPs for drug delivery are also thoroughly discussed. The biomimetic strategies, including the cell-membrane camouflaging technique and CD47 functionalization for the development of stealth nano-delivery systems, are highlighted in this review as well.

Engineered nanomaterials hold promise for a wide range of applications in medicine. However, safe use of nanomaterials requires that interactions with biological systems, not least with the immune system, are understood. Do nanomaterials elicit novel or unexpected effects, or is it possible to predict immune responses to nanomaterials based on how the immune system handles pathogens? How does the bio-corona of adsorbed biomolecules influence subsequent immune interactions of nanomaterials? How does the grafting of polymers such as poly(ethylene glycol) onto nanomaterial surfaces impact on these interactions? Can ancient immune evasion or "stealth" strategies of pathogens inform the design of nanomaterials for biomedical applications? Can nanoparticles co-opt immune cells to target diseased tissues? The answers to these questions may prove useful for the development of nanomedicines. [ABSTRACT FROM AUTHOR]

Abstract For electrically large targets, the scattering mechanics are specular reflection, edge diffraction, multiple reflection, etc. Multiple reflection scattering mechanics is the mainly contribution for complex targets.Diagnosis of the scattering structure which causes this mechanics is difficult to judge and orientate. In current paper, a hotspot analysis method is proposed according to the laws of physical optics and geometrical optics, which can intuitively show the contribution of different parts to the overall radar cross section (RCS), so as to judge the components which cause the strong scattering sources and to quantitatively describe the scattering mechanic of complex targets. Hotspot analysis has great application in the analysis of target electromagnetic scattering, the design and development of target simulators, and the stealth transformation of targets. [ABSTRACT FROM AUTHOR]

This paper investigates the absorption features of the symmetric G-shape metamaterial absorber (MA) at the microwave frequency range for the ultra-wideband. The proposed metamaterial structure attains above 95% absorptivity in the frequency range of 20-60 GHz. It also analyses the absorptivity of the ultra-wideband MA for the different incidence angles of the electromagnetic (EM) wave. The absorptivity is the function of the angle of incidence of EM waves for the proposed G-shape metamaterial structure and it attains maximum absorptivity for the normal incidence. Such a wideband absorber would be useful for the multifarious applications including wideband filtering and stealth metamaterial in the Ku, K-, Ka- Q- and U-bands. [ABSTRACT FROM AUTHOR]

Copyright of China Textile Leader is the property of China Textile Information Center and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

It is well known that radar absorbing potentiality of existing magneto-dielectric composites can be significantly enhanced by the application of frequency selective surface (FSS) and cascaded electromagnetic (EM) structures. But the optimization of such complex EM structures and validation of the adopted optimization strategy is still a very challenging task for the researchers. Therefore, in this study, an effective effort has been made for the optimization and the corresponding validation for Single Square FSS (SS-FSS) impinged and cascaded radar wave absorbers using advanced computational EM software’s like FEldberechnung fur Korper mit beliebiger Oberflache - a German acronym (FEKO) and high frequency structure simulator (HFSS). In addition, a critical analysis of dielectric constant (ε′) has been carried out to select the best combination of composites for the development of efficient radar wave absorbers. A comparison between optimized and simulated results have been carried out to examine the effect of advanced EM approaches over reflection loss (RL) characteristics of composite radar absorbing materials (CRAMs). A rapid change in radar absorption properties of composites has been observed after the application of SSFSS and cascading. A SS-FSS impinged composite has been found to provide a wide absorption bandwidth of 3.6 GHz at X-band. A cascaded absorber having layer thickness 1.8 mm provides a peak RL of −42.6 dB at 10.6 GHz with an absorption bandwidth of 2.5 GHz. The strong agreement between mathematical model, HFSS and FEKO results clearly reflects the efficiency of adopted approach for distinct practical EM applications. [ABSTRACT FROM AUTHOR]

Echolocation allows bats to occupy diverse nocturnal niches. Bats almost always use echolocation, even when other sensory stimuli are available to guide navigation. Here, using arrays of calibrated infrared cameras and ultrasonic microphones, we demonstrate that hoary bats (Lasiurus cinereus) use previously unknown echolocation behaviours that challenge our current understanding of echolocation. We describe a novel call type ('micro' calls) that has three orders of magnitude less sound energy than other bat calls used in open habitats. We also document bats flying close to microphones (less than 3 m) without producing detectable echolocation calls. Acoustic modelling indicates that bats are not producing calls that exceed 70-75 dB at 0.1 m, a level that would have little or no known use for a bat flying in the open at speeds exceeding 7 m s-1. This indicates that hoary bats sometimes fly without echolocation. We speculate that bats reduce echolocation output to avoid eavesdropping by conspecifics during the mating season. These findings might partly explain why tens of thousands of hoary bats are killed by wind turbines each year. They also challenge the long-standing assumption that bats--model organisms for sensory specialization--are reliant on sonar for nocturnal navigation. [ABSTRACT FROM AUTHOR]