Modified Kadomtsev–Petviashvili Equation for Description of Nonlinear Perturbations in Plasma of Dusty Lunar Exosphere

Plasma Physics Reports - Abstract—Modified Kadomtsev–Petviashvili equation describing nonlinear dynamics of nearly one-dimensional wave structures in dusty plasma above illuminated part...     

Dust–Acoustic Envelope Solitons and Rogue Waves in a Magnetized Electron-Depleted Plasma

Plasma Physics Reports - A theoretical investigation is made to study the properties of dust–acoustic (DA) waves, and corresponding dust–acoustic rogue waves (DARWs) in a magnetized...     

Analysis of the Fungal Flora in Environmental Dust Samples by PCR–SSCP Method

Conventional microbiological techniques yield only limited information on the composition of fungal communities in dust. The aim of this study was to establish and optimize PCR-single strand conformation polymorphism (PCR–SSCP) analysis for investigation of fungal diversity in rural dust samples. Three different DNA extraction protocols were tested on 38 fungal cultures. A total of six known universal fungal primer pairs were tested targeting the 18S rRNA gene, the 28S rRNA gene and the ITS region, respectively. Objective evaluation was performed with respect to the following parameters: efficiency to amplify all 38 strains; separation of seven species from different phylogenetic groups on the SSCP gel; additional bands in PCR–SSCP analysis; possibility to classify the amplified gene fragments to species level. Primer ITS1/ITS4 and PowerSoil? DNA isolation showed the best performance in most cases and were chosen for further analysis. The detection limit of the developed system was 200 CFU/g dust. Moreover, the reproducibility of the system could be demonstrated, leading to average profile similarities of 94.94 % [SD = 2.51] within gels, 93.03 % [SD = 4.69] between different days and 87.66 % [SD = 6.62] between different gels when testing shed and mattress dust samples. Sequencing allowed identification on species level, in detail: Alternaria alternata, Cladosporium sphaerospermum, Cladosporium cladosporioides as well as the yeasts Candida cabralensis and Candida catenulata. This demonstrates the adaptability of the method. In this study, a standardized system for fungal community analysis was developed that provides reproducible results applicable for epidemiological purposes.     

Studies on the Effect of Dust–Ion Collision on Dust–Ion Acoustic Solitary Waves in a Magnetized Dusty Plasma in the Framework of Damped KP Equation and Modified Damped KP Equation

Plasma Physics Reports - The influence of the dust–ion collision effect on the propagation of ion–acoustic waves (IAWs) in a collisional magnetized dusty plasma containing positive...     

Dust–Ion–Acoustic Solitary Wave Structure in Magnetized Plasma with Nonthermally Distributed Electrons and Positrons

Plasma Physics Reports - The dust–ion–acoustic (DIA) solitary wave (SW) propagation in a magnetized dusty plasma consisting of mobile positive and heavy negative ions, nonthermal...     

Impacts of invasive biota in forest ecosystems in an aboveground–belowground context

Forest ecosystems world-wide are being subjected to invasion by organisms representing all domains of life. Here we use a combined aboveground-belowground approach to provide a conceptual framework for assessing how forests respond to biological invasions. We first address mechanisms by which invasive plants and aboveground and belowground consumers impact on forests, and highlight that although we have a growing understanding of the determinants of the effects of invasive plants, for invasive consumers we have yet to move from a series of iconic case studies to the development of general principles. We also address the effects of invasive biota in the context of the drivers of invasion, co-invasion and invasional meltdown, the issue of simultaneous species gains and losses, and forest restoration and recovery post-invasion. We then highlight areas that would benefit from further work, particularly regarding underlying mechanisms, determinants of context-dependency of invader effects, and linkages between causes and consequences of invasion. In concluding, we emphasize that biological invaders have the potential for large-scale and long-term impacts on forest processes, and consideration of these impacts in an aboveground-belowground context will enable better prediction of future responses of forests to invaders and their management as well as of restoration efforts.     

Formation of Itraconazole–Succinic Acid Cocrystals by Gas Antisolvent Cocrystallization

Cocrystals of itraconazole, an antifungal drug with poor bioavailability, and succinic acid, a water-soluble dicarboxylic acid, were formed by gas antisolvent (GAS) cocrystallization using pressurized CO₂ to improve itraconazole dissolution. In this study, itraconazole and succinic acid were simultaneously dissolved in a liquid solvent, tetrahydrofuran, at ambient conditions. The solution was then pressurized with CO₂, which decreased the solvating power of tetrahydrofuran and caused crystallization of itraconazole–succinic acid cocrystals. The cocrystals prepared by GAS cocrystallization were compared to those produced using a traditional liquid antisolvent, n-heptane, for crystallinity, chemical structure, thermal behavior, size and surface morphology, potential clinical relevance, and stability. Powder X-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry, and scanning electron microscopy analyses showed that itraconazole–succinic acid cocrystals with physical and chemical properties similar to cocrystals produced using a traditional liquid antisolvent technique can be prepared by CO₂ antisolvent cocrystallization. The dissolution profile of itraconazole was significantly enhanced through GAS cocrystallization with succinic acid, achieving over 90% dissolution in less than 2 h. The cocrystals appeared stable against thermal stress for up to 4 weeks under accelerated stability conditions, showing only moderate decreases in their degree of crystallinity but no change in their crystalline structure. This study shows the utility of an itraconazole–succinic acid cocrystal for improving itraconazole bioavailability while also demonstrating the potential for CO₂ to replace traditional liquid antisolvents in cocrystal preparation, thus making cocrystal production more environmentally benign and scale-up more feasible.KEY WORDS: cocrystals, dissolution rate, gas antisolvent, itraconazole     

Radiative Surface Waves in Layered Plasma–Dielectric Structures and Prospects of Their Application in Plasma Microwave Electronics

Plasma Physics Reports - Surface waves in layered systems consisting of material media with different frequency dispersions are considered: dielectric–plasma–vacuum,...     

De Novo Formation of Left–Right Asymmetry by Posterior Tilt of Nodal Cilia

In the developing mouse embryo, leftward fluid flow on the ventral side of the node determines left–right (L-R) asymmetry. However, the mechanism by which the rotational movement of node cilia can generate a unidirectional flow remains hypothetical. Here we have addressed this question by motion and morphological analyses of the node cilia and by fluid dynamic model experiments. We found that the cilia stand, not perpendicular to the node surface, but tilted posteriorly. We further confirmed that such posterior tilt can produce leftward flow in model experiments. These results strongly suggest that L-R asymmetry is not the descendant of pre-existing L-R asymmetry within each cell but is generated de novo by combining three sources of spatial information: antero-posterior and dorso-ventral axes, and the chirality of ciliary movement.     

Cylindrical Magnetosonic Solitary Waves by Modified Korteweg–de Vries–Burgers Equation in Electron–Positron–Ion Plasma

Plasma Physics Reports - Theoretical investigations are carried out for the cylindrical magnetosonic solitary waves in dissipative, hot electron–positron–ion plasma. By the reductive...     

Nonlinear Wave Structures and Plasma−Dust Effects in the Earth’s Atmosphere

The interaction of charged dust grains with nonlinear vortical structures in the Earth’s atmosphere is analyzed. Certain aspects of the atmosphere?ionosphere interaction, in particular, mechanisms for the appearance of dust grains at ionospheric altitudes, are discussed. It is shown that, at certain altitudes, there are regions in the wavenumber space in which conditions leading to the excitation of acoustic?gravity waves are satisfied. The interaction of nonlinear acoustic?gravity waves with dust grains of meteoric origin at ionospheric altitudes, which leads to the mixing and redistribution of dust grains over the region where vortices exist, is investigated. The possibility of formation of vertical and horizontal dust flows in dusty ionospheric plasma as a result of modulational instability is analyzed. The dynamics of dust grains in dust devils frequently arising in the atmosphere above well-heated surfaces is modeled. The vortical structure of such a dust devil is characterized by a reduced pressure in the center, which facilitates the lifting of small dust grains from the surface. The formulated model is used to calculate the trajectories of dust grains in dust devils with allowance for the influence of the electric field generated in the vortex by colliding dust grains. The calculations show that dust devils play an important role in the transport of dust grains.     

Formation of 20β-dihydrosteroids by anaerobic bacteria

Cortisol was metabolized to a variety of products, among them small amounts of cortol by fecal flora of humans and rats.A microorganism. Bifidobacterium adolescentis, isolated from both sources, synthesized a 20-hydroxysteroid dehydrogenase which reduced cortisol to 20β-dihydrocortisol. The metabolite was reduced to cortol by Clostridium paraputrificum. The 20-hydroxysteroid dehydrogenase showed a wide substrate specificity; it was independent of the 4-ene and the configuration at C-3, C-11, C-17 and C-21. Cortol was resistant to any further alteration by human fecal flora, i.e. it is a metabolic end product. As expected. B. adolescenris effectively prevented 21-dehydroxylation of cortisol by Eubacterium lentum.     

Formation of γ-glutamylglycyglycine by extracellular glutaminase of Aspergillus oryzae

γ-Glutamylglycylglycine (γ-GluGlyGly) was formed through the γ-glutamyltranspeptidase (GGT) reaction catalyzed by glutaminase in a water extract of wheat bran koji obtained with Aspergillus oryzae MA-27-IM. The yield of γ-GluGlyGly was about 18% from l-glutamine in a reaction mixture containing 50 mM l-glutamine, 50 mM glycylglycine, and the extract (0.1 unit ml as GGT activity) in a 100 mM Tris-HCl buffer solution (pH 7.2), which was incubated for 7 h at 30°C. The γ-GluGlyGly formed was purified by ion exchange chromatographies, and the identified by chemical and enzymatic methods as well as by infrared and PMR spectroscopic analyses.     

On the Buildup of Ion–Acoustic Instability in Plasma with Two Types of Ions

Plasma Physics Reports - The issues of the onset of ion–acoustic instability of the reverse current in a hot plasma with parameters corresponding to the laser thermonuclear fusion plasma are...     

Formation of Inhalable Rifampicin–Poly(l-lactide) Microparticles by Supercritical Anti-solvent Process

Formation of inhalable microparticles containing rifampicin and poly(l-lactide) (L-PLA) by using supercritical anti-solvent process (SAS) was investigated. The solutions of drug and polymer in methylene chloride were sprayed into supercritical carbon dioxide. The effect of polymer content and operating conditions, temperature, pressure, carbon dioxide molar fraction, and concentration of solution, on product characteristics were studied. The prepared microparticles were characterized with respect to their morphology, particle size and size distribution, drug content, drug loading efficiency, and drug release characteristic. Discrete, spherical microparticles were obtained at high polymer:drug ratios of 7:3, 8:2, and 9:1. The shape of L-PLA microparticles became more irregular and agglomerated with decreasing polymer content. Microparticles with polymer content higher than 60% exhibited volumetric mean diameter less than 5 μm, but percent drug loading efficiency was relatively low. Drug-loaded microparticles containing 70% and 80% L-PLA showed a sustainable drug release property without initial burst release. Operating temperature level influenced on mean size and size distribution of microparticles. The operating pressure and carbon dioxide molar fraction in the range investigated were unlikely to have an effect on microparticle formation. An increasing concentration of feed solution provided larger size microparticles. Rifampicin-loaded L-PLA microparticles could be produced by SAS in a size range suitable for dry powder inhaler formulation.