In situ spectroscopic measurement of transmitted light related to defect formation in SiO2 during femtosecond laser irradiation

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Dopant dependence on passivation and reactivation of carrier after hydrogenation

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Hydrogen molecules trapped by multivacancies in silicon

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Codoping of boron and phosphorus in silicon nanowires synthesized by laser ablation

Codoping of boron (B) and phosphorus (P) atoms was performed during the synthesis of silicon nanowires (SiNWs) by laser ablation. The observation of a local vibrational mode of B clearly showed B doping in codoped SiNWs, while Fano broadening due to heavy B doping disappeared, indicating compensation by P donors. The electrospin resonance signal of conduction electrons also disappeared due to compensation by B acceptors. These results indicate that codoping of B and P atoms was achieved in SiNWs during laser ablation

Formation of Si nanocrystallites observed by in situ transmission electron microscopy and their effect on the enhancement of Er photoluminescence in Er-doped SiO2

The formation of Si nanocrystallites (nc-Si) in erbium (Er)-dispersed SiOx (x<=2) films was investigated by in situ annealing while performing transmission electron microscopy measurements. The correlation between the formation of nc-Si and Er ion emissions was also comprehensively investigated by photoluminescence and electron spin resonance measurements. The results showed that the formation of nano-Si region with the suitable size is important for enhancement of Er ion emission

Hydrogen Molecules in Crystalline Silicon Treated with Atomic Hydrogen

We report the first observation of the vibrational Raman spectrum of hydrogen molecules H2 in crystalline silicon treated with hydrogen atoms at 400 °C. The Raman spectrum of H2 in silicon observed at room temperature exhibits a frequency shift of around 4158 cm-1 and a very broad half-width of approximately 34 cm-1. An isotope shift was also detected at around 2990 cm-1 in silicon treated with deuterium atoms at 400 °C. The frequency shifts of the observed lines are in close agreement with those reported for H2 and D2 in the gas, liquid, and solid phases

Extracts of Feijoa Inhibit Toll-Like Receptor 2 Signaling and Activate Autophagy Implicating a Role in Dietary Control of IBD

Inflammatory bowel disease (IBD) is a heterogeneous chronic inflammatory disease affecting the gut with limited treatment success for its sufferers. This suggests the need for better understanding of the different subtypes of the disease as well as nutritional interventions to compliment current treatments. In this study we assess the ability of a hydrophilic feijoa fraction (F3) to modulate autophagy a process known to regulate inflammation, via TLR2 using IBD cell lines

Formation of hydrogen-boron complexes in boron-doped silicon treated with a high concentration of hydrogen atoms

The formation of hydrogen (H) related complexes and their effect on boron (B) dopant were investigated in B-ion implanted and annealed silicon (Si) substrates treated with a high concentration of H. Isotope shifts by replacement of 10B with 11B were observed for some H-related Raman peaks, but not for other peaks. This shows proof of the formation of B-H complexes in which H directly bonds to B in Si. This is an experimental result concerning the formation of B-H complexes with H bonded primarily to B. Electrical resistivity measurements showed that the B acceptors are passivated via the formation of the observed B-H complexes, as well as the well-known passivation center in B-doped Si; namely, the H-B passivation center

Transactivation of EGFR by LPS induces COX-2 expression in enterocytes

Necrotizing enterocolitis (NEC) is the leading cause of gastrointestinal morbidity and mortality in preterm infants. NEC is characterized by an exaggerated inflammatory response to bacterial flora leading to bowel necrosis. Bacterial lipopolysaccharide (LPS) mediates inflammation through TLR4 activation and is a key molecule in the pathogenesis of NEC. However, LPS also induces cyclooxygenase-2 (COX-2), which promotes intestinal barrier restitution through stimulation of intestinal cell survival, proliferation, and migration. Epidermal growth factor receptor (EGFR) activation prevents experimental NEC and may play a critical role in LPS-stimulated COX-2 production. We hypothesized that EGFR is required for LPS induction of COX-2 expression. Our data show that inhibiting EGFR kinase activity blocks LPS-induced COX-2 expression in small intestinal epithelial cells. LPS induction of COX-2 requires Src-family kinase signaling while LPS transactivation of EGFR requires matrix metalloprotease (MMP) activity. EGFR tyrosine kinase inhibitors block LPS stimulation of mitogen-activated protein kinase ERK, suggesting an important role of the MAPK/ERK pathway in EGFR-mediated COX-2 expression. LPS stimulates proliferation of IEC-6 cells, but this stimulation is inhibited with either the EGFR kinase inhibitor AG1478, or the selective COX-2 inhibitor Celecoxib. Taken together, these data show that EGFR plays an important role in LPS-induction of COX-2 expression in enterocytes, which may be one mechanism for EGF in inhibition of NEC

Identification of Giardia lamblia DHHC Proteins and the Role of Protein S-palmitoylation in the Encystation Process

Protein S-palmitoylation, a hydrophobic post-translational modification, is performed by protein acyltransferases that have a common DHHC Cys-rich domain (DHHC proteins), and provides a regulatory switch for protein membrane association. In this work, we analyzed the presence of DHHC proteins in the protozoa parasite Giardia lamblia and the function of the reversible S-palmitoylation of proteins during parasite differentiation into cyst. Two specific events were observed: encysting cells displayed a larger amount of palmitoylated proteins, and parasites treated with palmitoylation inhibitors produced a reduced number of mature cysts. With bioinformatics tools, we found nine DHHC proteins, potential protein acyltransferases, in the Giardia proteome. These proteins displayed a conserved structure when compared to different organisms and are distributed in different monophyletic clades. Although all Giardia DHHC proteins were found to be present in trophozoites and encysting cells, these proteins showed a different intracellular localization in trophozoites and seemed to be differently involved in the encystation process when they were overexpressed. dhhc transgenic parasites showed a different pattern of cyst wall protein expression and yielded different amounts of mature cysts when they were induced to encyst. Our findings disclosed some important issues regarding the role of DHHC proteins and palmitoylation during Giardia encystation.Fil: Merino, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; ArgentinaFil: Zamponi, Nahuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; ArgentinaFil: Vranych, Cecilia Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; ArgentinaFil: Touz, Maria Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; ArgentinaFil: Ropolo, Andrea Silvana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; Argentin