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Abstract: The aim of this study is to propose guidelines for the systems engineering of future stealth combat vehicles using Low Observable Technology (LOT). A case study approach, based on interviews and document reviews, was used to analyze the systems engineering processes of the SEP multirole armored vehicle and the Visby class corvette respectively. The result is a thorough investigation of what worked in the cases studied, but with lessons extrapolated into recommendations for future development programs. These will have to deal with an increasingly complex sensor threat and a transformed, multilateral, European procurement environment. The main conclusion is that coherence and traceability between military needs on the battlefield and signature requirements is expected to be particularly challenging. A workflow tailored for requirements analysis in LO combat vehicle programs has, therefore, been derived and is presented here. In addition, the most important enablers for future multilateral development programs involving LOT have been identified as: establishing common best practices, demonstrator programs, an integrated product team approach, and, in line with similar work on combat aircraft, establishing stealth as a key architectural principle. [ABSTRACT FROM AUTHOR]

The ever-changing battlefield environment, as well as the emergence of global command and control architectures currently used by armed forces around the globe, requires the use of robust and adaptive technologies integrated into a reliable platform. Unmanned Combat Aerial Vehicles (UCAVs) aim to integrate such advanced technologies while also increasing the tactical capabilities of combat aircraft. This paper provides a summary of the technical and operational design challenges specific to UCAVs, focusing on high-performance, and stealth designs. After a brief historical overview, the main technology demonstrator programmes currently under development are presented. The key technologies affecting UCAV design are identified and discussed. Finally, this paper briefly presents the main issues related to airworthiness, navigation, and ethical concerns behind UAV/UCAV operations. [ABSTRACT FROM AUTHOR]

This article argues that various contemporary media articulate an aesthetic of stealth, that is, the staging of acts of becoming-imperceptible. Furthermore, the article contends that the aesthetic of stealth resonates with a broader shift in the functioning of contemporary political culture, the requirements it formulates, and appropriate modes of action. The argument is presented in three case studies, each articulating one step in the argument: through Steyerl’s video pieceHow Not to Be Seen, the author situates stealth aesthetics in the political context of a shift away from struggles for visibility to a withdrawal from representation and the preoccupation with becoming-imperceptible. In an engagement with the TV seriesThe Americans, the author explains how exactly contemporary media, in this case television, produce an aesthetic of stealth, foregrounding the notion of ecological perception. Finally, an analysis of the changes in gameplay in the video game seriesTomb Raiderallows the author to elaborate, first, on how stealth gameplay fosters the embodied performance of ecological perception and, second, on how the media aesthetic of stealth infiltrates genres that traditionally rely on open confrontation and combat. [ABSTRACT FROM PUBLISHER]

This article analyzes a review of recent developments in the field of frequency selective surface (FSS)-based advanced electromagnetic (EM) structures. FSSs have been the subject of intensive investigation for distinct EM applications for more than four decades. An FSS is a type of filter consisting of an array of periodic metallic patches or apertures on a dielectric substrate. The high-pass (inductive FSS) and low-pass (capacitive FSS) filtering operation of FSS results in the exhibition of total transmission and reflection near the resonance wavelength. This paper deals with an overview of different FSS geometries, namely, traditional, active, fractal, three-dimensional and multilayered FSSs. A number of recent practical EM applications of FSS structures like microwave absorbers, radomes, textiles and antennas are discussed. In addition, different types of optimization and fabrication techniques for FSS-based EM structures are incorporated. The FSS-based research directions described in this study may be of interest to the scientific community working in this particular field. [ABSTRACT FROM AUTHOR]

Serrations at trailing edges of aircraft wing have long been known to suppress flow noise by suitably altering the flow at the trailing edge. Serrations at trailing edges are now also being used to reduce surface edge return contribution in scattering of electromagnetic waves by combat aircraft wing in order to reduce detectability by radar. A study was carried out on the efficacy of trailing edge serrations found in the wing of a barn owl, formed by its primary remiges or flight feathers, towards minimizing trailing edge related contributions by a common combat aircraft wing in an electromagnetic field. The barn owl is especially well known for its silent flight which is usually attributed to multiple adaptations in its wings including at the trailing edge. Barn owl type trailing edge serrations are appended to a planar metallic delta wing and subjected to an incident electromagnetic field. Electromagnetic scattering is predicted by numerically solving Maxwell’s equations using a finite volume time domain method and the radar cross-section calculated. [ABSTRACT FROM AUTHOR]

In order to study stealth strike-fighter, an analysis on stealth-aerodynamic integration and conceptual design is conducted. A conceptual 3-D digital model with internal antiship missiles and air-to-air missiles is designed in CATIA software. Based on the physical optics and equivalent electromagnetic current methods, using the self-programmed RCSAnsys software, the Radar Cross Section (RCS) characteristics and characteristics of scattering intensity distribution of the model are numerically simulated. Based on the turbulence theory of standard k-ε equations, using Fluent software, the pressure, velocity and lift-to-drag characteristics of the conceptual aircraft are numerically simulated. The simulation results show that the stealth and aerodynamic characteristics of the conceptual aircraft can be designed through integration analysis process, which can provide technical support to the design of the advanced operational aircrafts.

Infrared signature management (IRSM) has been a primary aeronautical concern for over 50 years. Most strategies and technologies are limited by the second law of thermodynamics. In this article, IRSM is considered in light of theoretical developments over the last 15 years that have put the absolute status of the second law into doubt and that might open the door to a new class of broadband IR stealth and cloaking techniques. Following a brief overview of IRSM and its current thermodynamic limitations, theoretical and experimental challenges to the second law are reviewed. One proposal is treated in detail: a high power density, solid-state power source to convert thermal energy into electrical or chemical energy. Next, second-law based infrared signature management (SL-IRSM) strategies are considered for two representative military scenarios: an underground installation and a SL-based jet engine. It is found that SL-IRSM could be technologically disruptive across the full spectrum of IRSM modalities, including camouflage, surveillance, night vision, target acquisition, tracking, and homing.

The tactical need for fixed wing aircraft with hovering capably has long been recognized bythe military for two reasons: increased safety when landing on aircraft carriers and higher velocitiesthat the ones obtainable with rotary wing aircraft.Thus far, the only concept governing the field of vertical flight was to use thrust either from a liftfan-F35, puffer ducts –Harrier or smaller jet engines-D0 31 or Yak-141, i.e. direct lift thrust.In this paper we will look at the prospect of using a combination of the Coanda effect with theVenturi effect to generate lift by so- called “supercirculation”. This novel approach can yield manyadvantages to conventional vertical lifting by providing a more stable platform and requiring lowerpower settings – and thus lower fuel consumption.The aircraft has a fixed, negatively sweped wing that uses circulation control to achieve lift atzero air speed. The fluid used for supercirculation will come from the fan thrust reversers – which, ifcorrectly managed, can give a sufficient flow for lifting the craft and also a negative thrust componentto compensate for the positive thrust of the primary flow (not diverted).

Microwave absorbers (MAs) are specially designed structures which dissipate an incident electromagnetic (EM) wave by converting it into thermal energy and thereby prevents reflection and/ or transmission. The MAs are extensively in demand due to their property to reduce the electromagnetic wave interference (EMI) and to enhance electromagnetic shielding (EMS). MAs are also used in potential military applications as a stealth technology to design stealth aircrafts, warships and army clothing etc. due to the reduction of radar cross section (RCS) of the defense equipment by the absorber coating. In this review work, study of metamaterial-based MAs, their characteristics viz. left-handed material property, permittivity and permeability have been discussed in detail. Metamaterials (MMs) or artificial materials that play a significant role in reducing the size and thickness of MAs depending upon the frequency of operation. In this work, theoretical background of MM-based absorbers detailing the effect of permittivity and permeability on absorber performance has also been discussed. Different applications of absorbers are elaborately covered in this paper. Furthermore, frequency selective surface (FSS) which is a two-dimensional array has the capability to reflect or transmit EM wave completely or partially depending upon the nature of FSS. Therefore, distinct categories of FSS-based absorbers are discussed according to the frequency of operation, bandwidth and material specification where the effect of different design parameters is also critically analyzed. The objective of this review paper is to provide an exhaustive study of the unique attributes of MAs having a diverse range of applications for frequencies ranging from microwave, terahertz upto optical frequency domain. This review paper is certainly a vital tool for researchers to accurately understand, explore and work on MA design and selection as per user defined specific frequency and applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Integrated frequency selective surface (IFSS) absorbers with larger bandwidth, effective reflection loss, polarization-insensitive characteristics, angular stability with compact/thin design, and ease of fabrication have captivated significant importance in stealth technology. Herein, we report on an IFSS absorber that has been designed, simulated, and implemented for manufacturing to achieve effective stealth properties. Initially, frequency selective surface (FSS) layers have been designed that comprise a closed centroid honeycomb structure surrounded with four annular hexagonal rings, splitted, alternatively, and enveloped with four L-shaped elements. The simulated pattern has been optimized on glass fabric for reflection loss ( R C , dB) at a thickness of ∼0.1 mm by choosing sheet resistance of pattern 110 Ω/□. A FSS layer combined with interlayer lossy dielectric laminates (1.8 mm) and a carbon-fabric-reinforced-plastic ground has been simulated as an IFSS absorber. The performance of R C , in normal and angular configuration (0-60°), under transvers an electric/magnetic mode of polarization, including analysis of the displacement current, volume power loss distribution, and complex admittance has been carried on IFSS. Subsequently, the proposed absorber has been fabricated using customized carbon-based resistive ink imprinted on glass fabric by mask lithography compounded with laminates (a carbon black powder/epoxy composite) and ground. Their manufacturing details, including free space and anechoic chamber R C corresponds to a lower operating frequency), covering 76% fractional bandwidth in X and Ku bands. The proposed design architecture of the IFSS is ideally suitable for aerospace stealth platforms.R C performances of the absorber are found to be in good agreement, possessing minimal 10 dB reflection loss (90% absorption) with a sample thickness of 1.9 mm (0.05λ L , where λ L corresponds to a lower operating frequency), covering 76% fractional bandwidth in X and Ku bands. The proposed design architecture of the IFSS is ideally suitable for aerospace stealth platforms.

In the present work, milled nanocrystals of a poorly soluble compound using different stabilizers were prepared and characterized. The aim of the study was to evaluate a fundamental set of properties of the formulations prior to i.v. injection of the particles. Two polyethylene oxide containing stabilizers; (distearoyl phosphatidylethanol amine (DSPE)) −PEG2000 and the triblock copolymer Pluronic F127, were investigated, with and without polyvinylpyrrolidone K30/Aerosol OT (PVP/AOT) present. The solubility in water was around 10 nM for the compound, measured from nanocrystals, but 1000 times higher in 4% human serum albumin. The particles were physically stable during the time investigated. The zeta potential was around −30 and −10 mV for DSPE-PEG2000 and Pluronic F127 stabilized particles, respectively, at the conditions selected. The dissolution rate was similar for all four formulations and similar to the theoretically predicted rate. Critical micelle concentrations were determined as 56 nM and 1.4 μM for DSPE-PEG2000 and Pluronic F127, respectively. The adsorption isotherms for the PEG lipid showed a maximum adsorbed amount of about 1.3 mg/m 2 , with and without PVP/AOT. Pluronic F127 showed a higher maximum amount adsorbed, at around 3.1 mg/m 2 , and marginally lower with PVP/AOT present. Calculated data showed that the layer of Pluronic F127 was thicker than the corresponding DSPE-PEG2000 layer. The total amount of particles distributed mainly to the liver, and the hepatocellular distribution in vitro (Liver sinusoidal endothelial cells and Kupffer cells), differed depending on the stabilizing mixture on the particles. Overall, DSPE-PEG2000 stabilized nanocrystals (with PVP/AOT) accumulated to a larger degree in the liver compared to particles with Pluronic F127 on the surface. A theoretical model was developed to interpret in vivo pharmacokinetic profiles, explaining the balance between dissolution and liver uptake. With the present, fundamental data of the nanocrystal formulations, the platform for forthcoming in vivo studies was settled. [ABSTRACT FROM AUTHOR]

A previous investigation suggested that a surface bearing a rinsing-resistant depot (nanocoating) of albumin is more protein-repulsive than the same surface physically pegylated by a poly(D,L-lactic acid)-poly(ethylene oxide) diblock copolymer. To complement the study, Optical Waveguide Lightmode Spectroscopy was used to compare the mass and the thickness of protein depots from different systems, namely albumin alone at different concentrations, a mixture of albumin + fibrinogen + γ-globulin at their physiological concentrations, and sheep serum. The same standard OWLS protocol was applied to compare data for bare sensor chips, for chips covered by an albumin nanocoating, and for chips physically pegylated using poly(D,L-lactic acid)-poly(ethylene oxide) diblock copolymers with different compositions and block lengths. The strategy and the conditions being rather different from those generally used to study pegylation-related antifouling properties; the literature was first reviewed critically. Then full coverage of sensor chips by albumin was demonstrated. The comparative study confirmed that albumin was more protein-repulsive than any of the diblock copolymers, irrespective of the protein system. Furthermore, it was found that pegylated surfaces were albumin-repulsive only when the concentration of the protein solution flowing over the surface was very low (0.1 g/L). It was not possible to correlate the copolymer data to PEO chain density, chain length and existence of brush. Thein vitrorepulsive activity of albumin was not affected by drying and rehydration, a feature of interest for storage of albumin-coated surfaces. All these observations confirmed our preliminary findings and showed that considering model proteins individually or in mixtures at concentrations far from physiological concentrations are not suitable to reflect the reality of full blood-surface interactions. [ABSTRACT FROM AUTHOR]

The article presents a case study of a six-year-old female, spayed American Pitbull terrier suffering from progressive lethargy, weakness, and anorexia for three-weeks duration. It discusses the results of the patient animal's physical examination, thoracic auscultation, neurological examination, as well as its abbreviated abdominal and thoracic ultrasound examinations.

Contrast agents are currently being modified to combine diagnostic and therapeutic capabilities. For ultrasound (US) imaging with polymeric contrast agents, it is necessary to modify the shell to create “stealth” microbubbles but without these modifications sacrificing the agent's ability to interact with the focused US beam. We hypothesize that addition of the classic immune shielding molecule polyethylene glycol (PEG) to a polylactide (PLA) microbubble shell will affect the acoustic and physical properties of the resulting agents. In an effort to determine the best formulation to achieve a balance between stealth and acoustic activity, we compared two PEGylation techniques; addition of increasing amounts of PEG-PLA copolymer and employing incorporation of a PEG lipid (LipidPEG) into the shell. Loss of acoustic enhancement occurred in a dose-dependent manner for both types of PEGylated agents (loss of signal occurred at >5 wt% PEG-PLA and >1 wt% LipidPEG), while immune activation was also reduced in a dose-dependent manner for the PEG-PLA agents. This study shows that the balance between acoustic behavior and improved immune avoidance was scalable and successful to different degrees with both PEGylation methods, and was best achieved using for PEG-PLA at 5 wt% and for LipidPEG at 1 wt%. Studies are ongoing to evaluate the best method for the targeting and drug delivery capabilities of these agents for applications in cancer treatment. This study represents the basis for understanding the consequences of making modifications to the native polymeric shell. [ABSTRACT FROM AUTHOR]

There are several clinical advantages of spleen targeting of nanocarriers. For example, enhanced splenic concentration of active agents could provide therapeutic benefits in spleen resident infections and hematological disorders including malaria, hairy cell leukemia, idiopathic thrombocytopenic purpura, and autoimmune hemolytic anemia. Furthermore, spleen delivery of immunosuppressant agents using splenotropic carriers may reduce the chances of allograft rejection in organ transplantation. Enhanced concentration of radiopharmaceuticals in the spleen may improve visualization of the organ, which could provide benefit in the diagnosis of splenic disorders. Unique anatomical features of the spleen including specialized microvasculature environment and slow blood circulation rate enable it an ideal drug delivery site. Because there is a difference in blood flow between spleen and liver, splenic delivery is inversely proportional to the hepatic uptake. It is therefore desirable engineering of nanocarriers, which, upon intravenous administration, can avoid uptake by hepatic Kupffer cells to enhance splenic localization. Stealth and non-spherical nanocarriers have shown enhanced splenic delivery of active agents by avoiding hepatic uptake. The present review details the research in the field of splenotropy. Formulation strategies to design splenotropic drug delivery systems are discussed. The review also highlights the clinical relevance of spleen targeting of nanocarriers and application in diagnostics. [ABSTRACT FROM AUTHOR]

Topical route of administration is the most commonly used method for the treatment of ophthalmic diseases. However, presence of several layers of permeation barriers starting from the tear film till the inner layers of cornea make it difficult to achieve the therapeutic concentrations in the target tissue within the eye. In order to circumvent these barriers and to provide sustained and targeted drug delivery, tremendous advances have been made in developing efficient and safe drug delivery systems. Liposomes due to their unique structure prove to be extremely beneficial drug carriers as they can entrap both the hydrophilic and hydrophobic drugs. The conventional liposomes had several drawbacks particularly their tendency to aggregate, the instability and leakage of entrapped drug and susceptibility to phagocytosis. Due to this reason, for a long time, liposomes as drug delivery systems did not attract much attention of researchers and clinicians. However, over recent years development of new generation liposomes has opened up new approaches for targeted and sustained drug delivery using liposomes and has rejuvenated the interest of researchers in this field. In this review we present a summary of current literature to understand the anatomical and physiological limitation in achieving adequate ocular bioavailability of topically applied drugs and utility of liposomes in overcoming these limitations. The recent developments related to new generation liposomes are discussed. [ABSTRACT FROM AUTHOR]

Rheumatoid arthritis (RA) is the most common inflammatory rheumatic disease, affecting almost 1% of the world population. Although the cause of RA remains unknown, the complex interaction between immune mediators (cytokines and effector cells) is responsible for the joint damage that begins at the synovial membrane. Activated macrophages are critical in the pathogenesis of RA and showed specifically express a receptor for the vitamin folic acid (FA), folate receptor β (FRβ). This particular receptor allows internalization of FA-coupled cargo. In this review we will address the potential of nanoparticles as an effective drug delivery system for therapies that will directly target activated macrophages. Special attention will be given to stealth degree of the nanoparticles as a strategy to avoid clearance by macrophages of the mononuclear phagocytic system (MPS). This review summarizes the application of FA-target nanoparticles as drug delivery systems for RA and proposes prospective future directions. From the Clinical Editor Rheumatoid arthritis is a debilitating autoimmune disease of the joints which affects many people worldwide. Up till now, there is a lack of optimal therapy against this disease. In this review article, the authors outlined in depth the current mechanism of disease for rheumatoid arthritis and described the latest research in using folic acid-targeted nanoparticles to target synovial macrophages in the fight against rheumatoid arthritis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Protein corona interferes with the intended function of nanoparticles, such as target-specific interactions. • Previous efforts have focused on avoiding protein corona formation or overriding the effect of the protein corona. • Specific proteins in the blood, such as albumin or apolipoproteins, can enhance nanoparticle delivery to particular organs. • To exploit the functions of protein corona, nanoparticles are functionalized with the proteins or designed to attract them. • Remaining challenges include interpatient variability in serum proteins and poor understanding of non-protein corona. For systemically delivered nanoparticles to reach target tissues, they must first circulate long enough to reach the target and extravasate there. A challenge is that the particles end up engaging with serum proteins and undergo immune cell recognition and premature clearance. The serum protein binding, also known as protein corona formation, is difficult to prevent, even with artificial protection via "stealth" coating. Protein corona may be problematic as it can interfere with the interaction of targeting ligands with tissue-specific receptors and abrogate the so-called active targeting process, hence, the efficiency of drug delivery. However, recent studies show that serum protein binding to circulating nanoparticles may be actively exploited to enhance their downstream delivery. This review summarizes known issues of protein corona and traditional strategies to control the corona, such as avoiding or overriding its formation, as well as emerging efforts to enhance drug delivery to target organs via nanoparticles. It concludes with a discussion of prevailing challenges in exploiting protein corona for nanoparticle development. [ABSTRACT FROM AUTHOR]

Although PEG remains the gold standard for stealth functionalization in drug delivery field up to date, complete inhibition of protein corona formation on PEG-coated nanoparticles remains a challenge. To improve the stealth property of PEG, herein an α-glutamyl group was conjugated to the end of PEG and polymeric micelles with α-glutamyl-terminated PEG shells were prepared. After incubation with bovine serum albumin or in fetal calf serum, the size of the micelles changed slightly, while the size of the micelles of similar diblock copolymer but without α-glutamyl group increased markedly. These results indicated that the micelles with α-glutamyl-terminated PEG shells showed low non-specific protein adsorption. In vivo blood clearance kinetics assay showed that the micelles with α-glutamyl-terminated PEG shells exhibited a longer in vivo blood circulation time compared with similar micelles but without α-glutamyl groups. The better stealth property of the micelles with α-glutamyl-terminated PEG shells was presumably attributed to the zwitterionic property of the α-glutamyl groups. [ABSTRACT FROM AUTHOR]

The ideally invisible stealth radomes are usually sandwiched constructions composed of E-glass/epoxy composite, polyvinyl chloride foam and frequency selective surfaces (FSS). Nylon 6/6 and balsa wood are well known for their low dielectric properties. In this work the electromagnetic (EM) wave transmission characteristics of the existing stealth radomes were improved by employing nylon 6/6 fibre and balsa wood, along with E-glass/epoxy composite without compromising the mechanical properties. The free space measurement technique was performed to measure the EM wave transmission characteristics in the X-band frequency range (8.2-12.4 GHz) for a specific FSS. The flexural strength of the sandwiched constructions were investigated with three-point bending test. [ABSTRACT FROM AUTHOR]

The Great War ushered in a new era of long-distance combat. For the first time, weapons with a very long range were massively deployed, in previously unheard-of places: under the sea and in the air. Stealth fighting also included espionage and propaganda, now orchestrated on a global scale. In reaction to the carnage in the trenches, a degree of moral rehabilitation came to be conferred on the weapons initially associated with a “cowards’ war”. This in turn encouraged experimentation with the new, unmanned technology that would lead to the first prototypes of guided munitions and drones. [ABSTRACT FROM AUTHOR]

Liposomes have gained extensive attention as carriers for a wide range of drugs due to being both nontoxic and biodegradable as they are composed of substances naturally occurring in biological membranes. Active targeting for cells has explored specific modification of the liposome surface by functionalizing it with specific targeting ligands in order to increase accumulation and intracellular uptake into target cells. None of the Food and Drug Administration-licensed liposomes or lipid nanoparticles are coated with ligands or target moieties to delivery for homing drugs to target tissues, cells or subcellular organelles. Targeted therapies (with or without controlled drug release) are an emerging and relevant research area. Despite of the numerous liposomes reviews published in the last decades, this area is in constant development. Updates urgently needed to integrate new advances in targeted liposomes research. This review highlights the evolution of liposomes from passive to active targeting and challenges in the development of targeted liposomes for specific therapies. [ABSTRACT FROM AUTHOR]

Background: Frameless stereotactic neuronavigation has proven to be a feasible technology to acquire brain biopsies with good accuracy and little morbidity and mortality. New systems are constantly introduced into the neurosurgical armamentarium, although few studies have actually evaluated and compared the diagnostic yield, morbidity, and mortality of various manufacturer's frameless neuronavigation systems. The present study reports our experience with brain biopsy procedures performed using both the Medtronic Stealth Treon Vertek® and BrainLAB® Varioguide frameless stereotactic brain biopsy systems. Patients and methods: All 247 consecutive biopsies from January 2008 until May 2013 were evaluated retrospectively. One hundred two biopsies each were performed using the Medtronic (2008-2009) and BrainLAB® system (2011-2013), respectively. The year 2010 was considered a transition year, in which 43 biopsies were performed with either system. Patient demographics, perioperative characteristics, and histological diagnosis were reviewed, and a comparison was made between the two brain biopsy systems. Results: The overall diagnostic yield was 94.6 %, i.e., 11 biopsies were nondiagnostic, 5 (4.9 %) with the Medtronic and 6 (5.9 %) with the BrainLAB® system. No differences besides the operating time (108 vs 120 min) were found between the two biopsy methods. On average, 6.6 tissue samples were taken with either technique. Peri- and postoperative complications were seen in 5.3 % and 12.9 %, consisting of three symptomatic hemorrhages (1.2 %). Biopsy-related mortality occurred in 0.8 % of all biopsies. Conclusions: Regarding diagnostic yield, complication rate, and biopsy-related mortality, there seems to be no difference between the frameless biopsy technique from Medtronic and BrainLAB®. In contemporary time, the neurosurgeon has many tools to choose from, all with a relatively fast learning curve and ever improving feasibility. Thus, the issue of choice involves not the results, but the familiarity, end-user friendliness, and overall comfort when operating the system. [ABSTRACT FROM AUTHOR]

Niclosamide (NL) has demonstrated its great potential in fighting against leukaemia recently. However, either oral or systemic delivery of NL is challenged by its insoluble nature. Here, we developed two different NL-loaded submicron lipid emulsions (NL-SLEs) and compared their suitability in bioavailability enhancement. Conventional and PEGylated NL-SLEs (NL-CSLEs and NL-PSLEs) were prepared by melt dispersion/high pressure homogenisation technique. They were about 307.8 and 162.2 nm in particle size, respectively, and both of them possessed satisfactory stability and drug load (>9.0%). After oral administration, significantly enhanced bioavailability was achieved through NL-CSLEs and NL-PSLEs (441.11 and 463.55% relative to the reference). Apart from global size, NL-CSLEs and NL-PSLEs exhibited similar attributes in release, lipolysis, mucin binding, etc. Taken together, SLEs with or without PEG-lipid have shown to be promising for oral delivery of NL. PEG-lipid could significantly reduce the particle size of SLEs. But, macromolecular PEG-lipid was required to effectively stealth the lipid carriers. [ABSTRACT FROM PUBLISHER]

The pharmacological potential of curcumin (CURC) is severely restricted because of its low water solubility/absorption, short half-life and poor bioavailability. To overcome these issues, CURC-loaded nanoparticles (NPs) were produced by a double emulsion technique. In particular, NPs were made up of an amphiphilic blend of poloxamers and PLGA to confer stealth properties to the NPs to take advantage of the enhanced permeability and retention (EPR) effect. Different surface properties of NPs made up of bare PLGA and PLGA/poloxamer blend were confirmed by the different interactions of these NPs with serum proteins and also by their ability to be internalized by mesothelioma cell line. The uptake of PLGA/poloxamer NPs induces a persistent block in G0/G1 phase of the cell cycle up to 72 h, thus overcoming the drug tolerance phenomenon, normally evidenced with free CURC. [ABSTRACT FROM AUTHOR]

The results of a search for new physics in final states with jets, either photons or leptons, and low missing transverse momentum are reported. The study is based on a sample of proton–proton collisions collected at a center-of-mass energy s = 8 TeV with the CMS detector in 2012. The integrated luminosity of the sample is 19.7 fb −1 . Many models of new physics predict the production of events with jets, electroweak gauge bosons, and little or no missing transverse momentum. Examples include stealth models of supersymmetry (SUSY), which predict a hidden sector at the electroweak energy scale in which SUSY is approximately conserved. The data are used to search for stealth SUSY signatures in final states with either two photons or an oppositely charged electron and muon. No excess is observed with respect to the standard model expectation, and the results are used to set limits on squark pair production in the stealth SUSY framework. [ABSTRACT FROM AUTHOR]

Purpose: In this work we specifically investigate the molecular weight (Mw) dependent combinatorial properties of hyaluronic acid (HA) for exhibiting stealth and targeting properties using different Mw HA nanoshells to tune nanoparticle retargeting to CD44-expressing cancer cells. Methods: HA of different Mw was covalently grafted onto model polystyrene nanoparticles and advanced surface analysis by X-ray photoelectron spectroscopy performed to quantify and evaluate the effect of the coating procedure. Specific CD44-mediated retargeting was investigated by flow cytometry and confocal microscopy using isogenic D44-deficient and CD44-expressing MCF-7 breast adenocarcinoma cells. Results: Surface analysis demonstrated effective surface coating with 33, 260 and 900 kDa HA resulting in increased colloidal stability and highly negative surface charge due to presentation of up to 4.7% carboxyl groups that indicates an extended and non-constricted HA polymer surface. Reduced non-specific particle interaction in CD44 cells was shown for all HA nanoshells but CD44-dependent cellular retargeting and internalization in CD44 cells was highly dependent on the coating HA Mw properties. Conclusion: The combination of advanced surface characterization and evaluation of particle interactions in isogenic cells with and without CD44 receptor demonstrates direct evidence for the dual capacity of HA for stealth and CD44-mediated retargeting tunable by the HA molecular weight. [ABSTRACT FROM AUTHOR]

We report a novel, triple-layered composite composed of multi-walled nanotubes (MWNTs) dispersed in an epoxy/cotton fabric resistive layer that is sandwiched between two MWNT-dispersed E-glass fiber/epoxy dielectric absorbing layers. This structure efficiently absorbs microwave radiation over a frequency range of 2–18 GHz. This layered, composite structure is thin relative to previously developed, multi-layer systems with a resistive layer/low dielectric layer/resistive layer/low-dielectric layer structure. The paper-like resistive layer facilitates broadband microwave absorption by matching the impedance between the two absorbing layers. The E-glass fiber/epoxy laminate composites provide structural and mechanical support. The conductive MWNT filler controls dielectric losses through the formation of a network that allows high complex permittivity at low concentrations. Free-space measurements showed that the resulting triple-layered structure boasts an outstandingly broad bandwidth of reflection loss below −10 dB from 4.7 to 13.7 GHz. This new multi-layer structure offers a promising solution for attenuating electromagnetic waves over broad frequency ranges. [ABSTRACT FROM AUTHOR]

In 2005 and in 2012, the SHarp Edge Flight EXperiment SHEFEX I and SHEFEX II of DLR have been established. Low lift-to-drag ratio of them limits active control ability. This paper studies on a sharp-edge stealthy re-entry vehicle with high lift-to-drag ratio. The focus will be laid upon designing and modeling of a sharp-edge stealthy re-entry vehicle by analyzing of lift-to-drag ratio and center of gravity, and also upon stealth performance researches. All aerodynamic performance analysis are based on Modified Newtonian Theory, it's proved to be more precise for a sharp-edge hypersonic re-entry vehicle relative to the Piston Theory and Shock-Expansion Method. A procedure based on physical optics and method of equivalent currents for radar cross section calculation. As result, the configuration and the center of gravity are determined, and a good stealth performance is demonstrated. [ABSTRACT FROM AUTHOR]

The study of lock-on envelop of an aircraft is of fundamental interest for determining its susceptibility to infrared (IR) guided threats. The performance of IR signature suppression system for aircraft engine is affected by the penalties associated with its installation. This paper gives the qualitative and quantitative assessment on the IR lock-on range ( R LO ) due to increase in the engine back-pressure penalty, for several operating conditions. As a case study, the effect of reducing the exit area of a choked convergent nozzle of a turbojet engine on its IR signature is analyzed. Reduction in exit area of choked convergent nozzle below the design point value results in optical blockage of hot parts and therefore, solid angle subtended by the hot parts reduces. But the effect of back-pressure penalty is to increase the IR signature from the rear aspect and in the net, the IR signature and R LO for the same thrust level increases. Polar plots in 2-D of R LO for different view angles with reduction in choked convergent nozzle exit area in horizontal and vertical planes are examined for 3–5 μm band. [ABSTRACT FROM AUTHOR]

Malware has become a significant, complex, and widespread problem within the computer industry. It represents one of the most prevalent threats to cybersecurity and is increasingly able to circumvent current detection and mitigation techniques. To help better understand when a malware attack might happen, this article proposes an intention-based classification of malware and merges it with an optimal timing model to help predict the timing of malware based on its classification. The classification model is based on an examination of eight malware samples, and it identifies four malware classifications and commonalities based on the dimensions of persistence and stealth. The goal of the article is to provide a better understanding of when cyber-conflict will happen, and to help defenders better mitigate the potential damage. [ABSTRACT FROM AUTHOR]

Nanoparticulate systems have demonstrated significant potential for overcoming the limitations of non-specific adverse effects related to chemotherapy. The treatment of blood malignancies employing targeted particulate drug delivery systems presents unique challenges and considerable research has been focused towards the development of targeted liposomal formulations for B cell malignancies. These formulations are aimed at achieving selectivity towards the malignant cells by targeting several cell surface markers which are over-expressed in that specific malignancy. CD19, CD20, CD22 and CD74 are few of such markers of which CD19, CD22 and CD74 are internalizing and CD20 is non-internalizing. Systems which have been developed to target both types of these cell surface markers are discussed. Specifically, the efficacy and development of targeted liposomes is considered. A number of studies have demonstrated the advantages of targeted liposomal systems encapsulating doxorubicin or vincristine. However, liposomal encapsulation of newer anti-neoplastic agents such as AD 198 which are superior to doxorubicin should be considered. [ABSTRACT FROM AUTHOR]