Projectile Fire-Control Algorithm in a Spatially Varying Wind Field

The fire-control solution is an important element of any modern weapon system, providing precise aiming of the gun to enable highly accurate projectile impact. To be practical, the fire-control solution must be computed rapidly and reliably while simultaneously including all pertinent physical effects that can alter the trajectory and impact point. Current fire-control solutions account for the effect of atmospheric wind in a rudimentary manner, typically assuming a constant crosswind that is estimated in the field or measured at the firing site. With the advent of advanced wind-measurement systems (light detection and ranging, for example), it is now possible to accurately measure threedimensional wind velocities at numerous points approximately along the path of a direct-fire projectile. This article first shows the importance of wind knowledge along the line of fire for accuracy, particularly for long-range direct-fire shots. Then, a method to compute the fire-control solution of a projectile is defined, including the effect of exactly known spatially varying winds. By using a modified form of projectile linear theory that incorporates threedimensional linearly varying atmospheric winds, a closed-form fire-control solution is obtained. Moreover, the solution can be rapidly computed. The key to the algorithm is partitioning the projectile linear-theory state-transition matrix in an input–output form that enables the aiming solution to be computed in terms of a desired impact point and measured atmospheric winds. The application of this algorithm is restricted to flat-fire trajectories where the angle of attack of the projectile remains low throughout because this is the key limitation of the projectile linear theory that must be maintained. The proposed algorithm is exercised on an example fire-control problem for such flat-fire trajectories with excellent results

Analysis of viral pathogens in children with community acquired pneumonia (CAP) at two selected teaching hospitals in Colombo, Sri Lanka

Background: Community acquired pneumonia is an important cause of morbidity and mortality in children. Infection is caused by many different organisms and rational treatment depends on the identification of causative agents.Objectives: To describe the viral pathogens in community acquired pneumonia in children at two selected teaching hospitals in Colombo.Methods: A descriptive cross sectional study was carried out including 123 children, 3 months to 14 years of age admitted to two teaching hospitals with a clinical diagnosis of CAP. A nasopharyngeal sample was collected from each child and analyzed using multiplex real time PCR assay. FBC and CRP were done. Chest X-rays were blindly reported by a radiologist and categorized into 3 groups according to the WHO classification 1) Primary end-point consolidation/pleural effusion 2) Other consolidation/infiltrate 3) No consolidation/infiltrate/effusion.Results: Female to male ratio of this group was 1.5:1 and mean age was 40 months. The mean values for CRP and WBC were 51.41mg/L and 14.97/μL respectively. Out of123 samples one was negative for any organism. At least one virus was detected in 111 samples (90.2%). A single virus was present in the majority (60.4%) of cases and multiple viruses in the rest (39.6%). The commonest was Respiratory Syncytial virus (43.2%). Rhino, Parainfluenza and Adeno viruses were more abundant than Influenza A, Corona, Influenza B, Boca, Metapneumo, Entero and Parecho viruses. Both bacteria and viruses were detected in 77 samples. Ninety CXRs were reported in the group positive for viruses and category 2 was the commonest (55.6%).Conclusions: Viruses are predominant in paediatric CAP and co-infections with multiple viruses are fairly common.Acknowledgement: University Grant- ASP/01/RE/MED/2017/3

The Surfactant Dipalmitoylphophatidylcholine (DPPC) Modifies Acute Responses in Alveolar Carcinoma Cells in Response to Low Dose Silver Nanoparticle Exposure

Nanotechnology is a rapidly growing field with silver nanoparticles (AgNP) in particular utilized in a wide variety of consumer products. This has presented a number of concerns relating to exposure and the associated toxicity to humans and the environment. As inhalation is the most common exposure route, this study investigates the potential toxicity of AgNP to A549 alveolar epithelial carcinoma cells and the influence of a major component of lung surfactant dipalmitoylphosphatidylcholine (DPPC) on toxicity. It was illustrated that exposure to AgNP generated low levels of oxidative stress and a reduction in cell viability. While DPPC produced no significant effect on viability studies its presence resulted in increased reactive oxygen species formation. DPPC also significantly modified the inflammatory response generated by AgNP exposure. These findings suggest a possible interaction between AgNP and DPPC causing particles to become more reactive, thus increasing oxidative insult and inflammatory response within A549 cell

The effect of pH, grain size, and organic ligands on biotite weathering rates

Biotite dissolution rates were determined at 25 °C, at pH 2–6, and as a function of mineral composition, grain size, and aqueous organic ligand concentration. Rates were measured using both open- and closed-system reactors in fluids of constant ionic strength. Element release was non-stoichiometric and followed the general trend of Fe, Mg > Al > Si. Biotite surface area normalised dissolution rates (ri) in the acidic range, generated from Si release, are consistent with the empirical rate law: ri=kH,iaxiH+ where kH,i refers to an apparent rate constant, aH+ designates the activity of protons, and xi stands for a reaction order with respect to protons. Rate constants range from 2.15 × 10−10 to 30.6 × 10−10 (molesbiotite m−2 s−1) with reaction orders ranging from 0.31 to 0.58. At near-neutral pH in the closed-system experiments, the release of Al was stoichiometric compared to Si, but Fe was preferentially retained in the solid phase, possibly as a secondary phase. Biotite dissolution was highly spatially anisotropic with its edges being ∼120 times more reactive than its basal planes. Low organic ligand concentrations slightly enhanced biotite dissolution rates. These measured rates illuminate mineral–fluid–organism chemical interactions, which occur in the natural environment, and how organic exudates enhance nutrient mobilisation for microorganism acquisition

Dynamic Measurements of Membrane Insertion Potential of Synthetic Cell Penetrating Peptides

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Langmuir, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://doi.org/10.1021/la403370p.Cell penetrating peptides (CPPs) have been established as excellent candidates for mediating drug delivery into cells. When designing synthetic CPPs for drug delivery applications, it is important to understand their ability to penetrate the cell membrane. In this paper, anionic or zwitterionic phospholipid monolayers at the air-water interface are used as model cell membranes to monitor the membrane insertion potential of synthetic CPPs. The insertion potential of CPPs having different cationic and hydrophobic amino acids were recorded using a Langmuir monolayer approach that records peptide adsorption to model membranes. Fluorescence microscopy was used to visualize alterations in phospholipid packing due to peptide insertion. All CPPs had the highest penetration potential in the presence of anionic phospholipids. In addition, two of three amphiphilic CPPs inserted into zwitterionic phospholipids, but none of the hydrophilic CPPs did. All the CPPs studied induced disruptions in phospholipid packing and domain morphology, which were most pronounced for amphiphilic CPPs. Overall, small changes to amino acids and peptide sequences resulted in dramatically different insertion potentials and membrane reorganization. Designers of synthetic CPPs for efficient intracellular drug delivery should consider small nuances in CPP electrostatic and hydrophobic properties

The effect of acids on dipalmitoyl phosphatidylcholine (DPPC) monolayers and liposomes

Dipalmitoyl phosphatidylcholine (DPPC) is the most abundant phospholipid in lung surfactant, primarily responsible for the reduction of surface tension to near 0 mN/m during expiration. In addition, DPPC liposomes are also used for drug delivery. In this study, the effects of hydrochloric acid, nitric acid and sulphuric acid on various properties of DPPC was investigated. The surface pressure versus area isotherms of DPPC monolayers at different concentrations of acid were obtained using a Langmuir-Blodgett trough. Distinct changes in the shapes of DPPC isotherms were observed in presence of acid. The lift off area for DPPC control at pH 7.4 was 58 angstrom(2). The lift off area for DPPC was 105, 100 and 95 angstrom(2) at concentration of 15.5 x 10(-2) mol/dm(3) of nitric acid, sulphuric acid and hydrochloric acid respectively. Collapse plateaus were longest in presence of nitric acid compared to hydrochloric acid and sulphuric acid. The nitric acid treated liposomes showed improved adsorption as evidenced by lower surface tension values achieved within 1 s at concentrations ranging from 3.1 x 10(-6) to 15.5 x 10(-4) mol/dm(3) having pH 6.2-2.9. The inhibitory concentrations of nitric acid which significantly increased the average surface tension values achieved within 1 s were 3.1 x 10(-3) to 15.5 x 10(-2) mol/dm(3) (pH 2.6-1.0). The sulphuric acid treated liposomes showed improved adsorption at concentrations of 3.1 x 10(-6) to 3.1 x 10(-2) mol/dm(3) (pH 6.1-1.7). The adsorption was significantly inhibited at pH 1.4-0.4 achieved with sulphuric acid. The HCl-treated liposomes showed an improved adsorption at concentrations ranging from 3.1 x 10(-6) to 15.5 x 10(-2) mol/dm(3) (pH 6.4-1.3). The average surface pressure value achieved within 1 s at inhibitory concentration of 3.1 x 10(-1) mol/dm(3) of HCl at a pH of 0.83 was 10.1 +/- 2.2 mN/m. Acids did not affect the compressibility of DPPC. Increased leakage of calcein from DPPC liposomes at decreasing pH suggested increased permeability of DPPC liposomes under acidic conditions. The results of this study may have implications for pH dependent drug delivery in acidic conditions as well as for lung surfactant dysfunction in acid lung injury. (C) 200

Nanovesicle aerosols as surfactant therapy in lung injury

Acute lung injury causes inactivation of pulmonary surfactant due to leakage of albumin and other markers. Current surfactants are ineffective in this condition and are instilled intratracheally. Nanovesicles of 300 +/- 50 nm composed of nonlamellar phospholipids were developed as pulmonary surfactant aerosols for therapy in acid-induced lung injury. A combination of dipalmitoyl phosphatidylcholine and dioleoyl phosphatidylethanolamine was used. The size and composition of the nanovesicles were optimized for an improved airway patency in the presence of albumin and serum. In an acid-induced lung injury model in mice, on treatment with nanovesicle aerosols at a dose of 200 mg/kg, the alveolar protein leakage decreased from 8.62 +/- 0.97 mu g/mL to 1.94 +/- 0.74 mu g/mL, whereas the airway patency of the bronchoalveolar lavage fluid increased from 0.6 +/- 0.0% to 91.7 +/- 1.05%. Nanovesicle aerosols of nonlamellar lipids improved the resistance of pulmonary surfactants to inhibition and were promising as a noninvasive aerosol therapy in acute lung injury