Picosecond Laser Ablation of Silicon Single Crystal in a Liquid Environment

The picosecond Nd:YAG laser at wavelengths of 1064 nm was used to produced the silicon-based nanoparticles in de-ionized water. The main goal of our work presented here was enlight the role of thermal effects on the process of laser ablation of solid target in liquid. To accieve this goal the additional heating of the target surface by continuous laser was applied during the experiment. The shift of nanoparticles size distribution caused by applying of additional continuous laser was reported in this work. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3492

The Toxoplasma plant-like vacuolar compartment (PLVAC)

Toxoplasma gondii belongs to the phylum Apicomplexa and is an important cause of congenital disease and infection in immunocompromised patients. T. gondii shares several characteristics with plants including a nonphotosynthetic plastid termed apicoplast and a multivesicular organelle that was named the plant-like vacuole (PLV) or vacuolar compartment (VAC). The name plant-like vacuole was selected based on its resemblance in composition and function to plant vacuoles. The name VAC represents its general vacuolar characteristics. We will refer to the organelle as PLVAC in this review. New findings in recent years have revealed that the PLVAC represents the lysosomal compartment of T. gondii which has adapted peculiarities to fulfill specific Toxoplasma needs. In this review, we discuss the composition and functions of the PLVAC highlighting its roles in ion storage and homeostasis, endocytosis, exocytosis, and autophagy.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/175241/1/jeu12951.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/175241/2/jeu12951_am.pd

Nickel-based super-alloy Inconel 600 morphological modifications by high repetition rate femtosecond Ti:sapphire laser

The interaction of Ti:sapphire laser, operating at high repetition rate of 75 MHz, with nickel-based super-alloy Inconel 600 was studied. The laser was emitting at 800 nm and ultrashort pulse duration was 160 fs. Nickel-based super-alloy surface modification was studied in a low laser energy/fluence regime of maximum 20 nJ-15 mJ/cm(2), for short (10 s) and long irradiation times (range of minutes). Surface damage threshold of this material was estimated to be 1.46 nJ, i.e., 0.001 J/cm(2) in air. The radiation absorbed from Ti:sapphire laser beam under these conditions generates at the surface a series of effects. such as direct material vaporization, plasma creation, formation of nano-structures and their larger aggregates, damage accumulation, etc. Laser induced surface morphological changes observed on Inconel 600 were: (1) intensive removal Of Surface material with crater like features; (2) material deposition at near and farther periphery and creation of nano-aggregates/nano-structures; (3) sporadic micro-cracking of the inner and outer damage area. Generally. features created on nickel-based super-alloy surface by high repetition rate femtosecond pulses are characterized by low inner/outer damage diameter of less than 11 mu m/30 mu m and relatively large depth on the order of 150 mu m, in both low (10 s) and high (minutes) irradiation time regimes

Surface modification of a-CN/TiAlN double layer coating on ASP 30 steel induced by femtosecond laser with 10(13)-10(14) W/cm(2) intensity in vacuum

A double layer a-CN/TiAlN coating deposited on ASP30 steel substrate was irradiated by femtosecond laser and surface modification effects were observed. Moderate laser intensities used were in the range of 10(14)-10(13) W/cm(2), while the total thickness of double layer coating was 4.8 mu m (a-CN = 0.6 and TiAlN = 4.2 mu m). Laser-induced changes of the surface showed dependence on laser intensity and number of accumulated pulses. Irradiations at the highest intensity resulted in preservation of one or both layers up to 10 pulses, while at lower intensity (10(13) W/cm(2)) a-CN layer is removed after several pulses and TiAlN is preserved up to 50 pulses. Evaluated damage threshold of the target was 0.49 J/cm(2). Lower laser intensity irradiation produced periodic surface structures (LIPSS) over the entire irradiated spot with periodicity of similar to 700 nm, almost in agreement with the laser wavelength used. Irradiations carried out at the highest laser intensity (10(14) W/cm(2)) and laser pulse count of 50 resulted in the creation of crater like damages with depth up to 20 mu m. Craters were conically shaped, implying intensive processes which took place at the surface. Generation of LIPSS as well as craters can be of great interest for contemporary technologies

Surface modification of ASP 30 steel induced by femtosecond laser with 10(14) and 10(13) W/cm(2) intensity in vacuum

A study of ASP 30 steel surface modification with high intensity Ti:sapphire laser, operating at 804 nm wavelength and pulse duration of 60 fs, in vacuum ambient, is presented. ASP 30 steel surface variations were studied at laser intensities of 10(14) and 10(13) W/cm(2). The steel target specific surface changes and phenomena observed are: (i) Creation of craters at 10(14) W/cm(2) intensity; (ii) formation of periodic surface structures only at the reduced intensity of 10(13) W/cm(2); (iii) chemical surface changes registered only at higher laser intensity, and (iv) occurrence of plasma in front of the surface, including its emission in X-ray region. It can be concluded from this study that the reported laser intensities can effectively be applied for ASP 30 steel surface modification. Careful choosing of laser intensity and pulse count can lead to precise superficial material removal, for example laser intensity similar to 10(13) W/cm(2) and low pulse count can lead to ultra-precise surface processing. Generally, femtosecond laser surface modification of ASP 30 steel is non-contact and very rapid compared with traditional modification methods

Short-term exposure of mice to gasoline vapor increases the metallothionein expression in the brain, lungs and kidney

Environmental airborne pollution has been repeatedly shown to affect multiple aspects of brain and cardiopulmonary function, leading to cognitive and behavioral changes and to the pronounced inflammatory response in the respiratory airways. Since in the cellular defense system the important role might have stress proteins-metallothionein (MT)-I and MT-II, which are involved in sequestration and dispersal of metal ions, regulation of the biosynthesis and activities of zincdependent transcription factors, as well as in cellular protection from reactive oxygen species, genotoxicity and apoptosis, in this study we investigated their expression in the brain, lungs and kidney, following intermittent exposure of mice to gasoline vapor. Control groups consisted of intact mice and of those closed in the metabolic chamber and ventilated with fresh air. The data obtained by immunohistochemistry showed that gasoline inhalation markedly upregulated the MTs expression in tissues which were directly or indirectly exposed to toxic components, significantly increasing the number of MT I+II positive cells in CNS (the entorhinal cortex, ependymal cells, astroglial cells in subventricular zone and inside the brain parenchyma, subgranular and CA1-CA3 zone of the dentate gyrus in hippocampus and macrophages-like cells in perivascular spaces), in the lungs (pneumocytes type I and type II) and in the kidneys (parietal wall of Bowman capsule, proximal and distal tubules). The data point to the protective and growth-regulatory effects of MT I + II on places of injuries, induced by inhalation of gasoline vapor

Surface modification of a-CN/TiAlN double layer coating on ASP 30 steel induced by femtosecond laser with 10 13

A double layer a-CN/TiAlN coating deposited on ASP30 steel substrate was irradiated by femtosecond laser and surface modification effects were observed. Moderate laser intensities used were in the range of 10(14)-10(13) W/cm(2), while the total thickness of double layer coating was 4.8 mu m (a-CN = 0.6 and TiAlN = 4.2 mu m). Laser-induced changes of the surface showed dependence on laser intensity and number of accumulated pulses. Irradiations at the highest intensity resulted in preservation of one or both layers up to 10 pulses, while at lower intensity (10(13) W/cm(2)) a-CN layer is removed after several pulses and TiAlN is preserved up to 50 pulses. Evaluated damage threshold of the target was 0.49 J/cm(2). Lower laser intensity irradiation produced periodic surface structures (LIPSS) over the entire irradiated spot with periodicity of similar to 700 nm, almost in agreement with the laser wavelength used. Irradiations carried out at the highest laser intensity (10(14) W/cm(2)) and laser pulse count of 50 resulted in the creation of crater like damages with depth up to 20 mu m. Craters were conically shaped, implying intensive processes which took place at the surface. Generation of LIPSS as well as craters can be of great interest for contemporary technologies

The Toxoplasma Vacuolar H+-ATPase Regulates Intracellular pH and Impacts the Maturation of Essential Secretory Proteins

Summary: Vacuolar-proton ATPases (V-ATPases) are conserved complexes that couple the hydrolysis of ATP to the pumping of protons across membranes. V-ATPases are known to play diverse roles in cellular physiology. We studied the Toxoplasma gondii V-ATPase complex and discovered a dual role of the pump in protecting parasites against ionic stress and in the maturation of secretory proteins in endosomal-like compartments. Toxoplasma V-ATPase subunits localize to the plasma membrane and to acidic vesicles, and characterization of conditional mutants of the a1 subunit highlighted the functionality of the complex at both locations. Microneme and rhoptry proteins are required for invasion and modulation of host cells, and they traffic via endosome-like compartments in which proteolytic maturation occurs. We show that the V-ATPase supports the maturation of rhoptry and microneme proteins, and their maturases, during their traffic to their corresponding organelles. This work underscores a role for V-ATPases in regulating virulence pathways. : Stasic et al. characterize the function of the vacuolar proton ATPase in the life cycle of Toxoplasma gondii, a widespread parasite that infects almost one-third of the world’s population. The work presents molecular evidence of the pump’s role in the synthesis of virulence factors of a highly successful pathogen. Keywords: toxoplasma, vacuolar-H+-ATPase, intracellular pH, proton transport, plant-like vacuole, VAC, rhoptries, micronemes, lytic cycle, lysosom

An ortholog of Plasmodium falciparum chloroquine resistance transporter (PfCRT) plays a key role in maintaining the integrity of the endolysosomal system in Toxoplasma gondii to facilitate host invasion.

Toxoplasma gondii is an apicomplexan parasite with the ability to use foodborne, zoonotic, and congenital routes of transmission that causes severe disease in immunocompromised patients. The parasites harbor a lysosome-like organelle, termed the "Vacuolar Compartment/Plant-Like Vacuole" (VAC/PLV), which plays an important role in maintaining the lytic cycle and virulence of T. gondii. The VAC supplies proteolytic enzymes that contribute to the maturation of invasion effectors and that digest autophagosomes and endocytosed host proteins. Previous work identified a T. gondii ortholog of the Plasmodium falciparum chloroquine resistance transporter (PfCRT) that localized to the VAC. Here, we show that TgCRT is a membrane transporter that is functionally similar to PfCRT. We also genetically ablate TgCRT and reveal that the TgCRT protein plays a key role in maintaining the integrity of the parasite's endolysosomal system by controlling morphology of the VAC. When TgCRT is absent, the VAC dramatically increases in volume by ~15-fold and overlaps with adjacent endosome-like compartments. Presumably to reduce aberrant swelling, transcription and translation of endolysosomal proteases are decreased in ΔTgCRT parasites. Expression of subtilisin protease 1 is significantly reduced, which impedes trimming of microneme proteins, and significantly decreases parasite invasion. Chemical or genetic inhibition of proteolysis within the VAC reverses these effects, reducing VAC size and partially restoring integrity of the endolysosomal system, microneme protein trimming, and invasion. Taken together, these findings reveal for the first time a physiological role of TgCRT in substrate transport that impacts VAC volume and the integrity of the endolysosomal system in T. gondii