Characterization of nanoporous lanthanide-doped gadolinium gallium garnet powders obtained by propellant synthesis

In the present work we study the nanocrystalline powders of lanthanide-doped Gd3Ga5O12 (GGG, gadolinium gallium garnet) prepared using propellant synthesis. A series of GGG samples containing a number of different trivalent lanthanide ions (Tm, Er, Ho, Eu, Sm, Nd, and Pr) in different quantities (1%, 5%, 10%) were produced. Samples were characterized by X-ray diffraction (pre- and post calcination) for phase identification and line-broadening analysis, and by electron microscopy (SEM and TEM) for morphological and nanostructural investigation. Thermal behavior of the powder was investigated by thermal gravimetric analysis (TGA) and differential thermal analysis (DTA). The samples have a polycrystalline porous structure. Elemental microanalysis made by energy dispersive X-ray spectroscopy (EDX) detector attached to TEM and XRD unit-cell determinations confirmed that the lanthanides ions entered the structure of GGG. Crystallites have a high degree of disorder

Circulating microRNAs in Cerebrospinal Fluid and Plasma: Sensitive Tool for Detection of Secondary CNS Involvement, Monitoring of Therapy and Prediction of CNS Relapse in Aggressive B-NHL Lymphomas

Lymphoma with secondary central nervous system (CNS) involvement represents one of the most aggressive malignancies, with poor prognosis and high mortality. New diagnostic tools for its early detection, response evaluation, and CNS relapse prediction are needed. We analyzed circulating microRNAs in the cerebrospinal fluid (CSF) and plasma of 162 patients with aggressive B-cell non-Hodgkin’s lymphomas (B-NHL) and compared their levels in CNS-involving lymphomas versus in systemic lymphomas, at diagnosis and during treatment and CNS relapse. We identified a set of five oncogenic microRNAs (miR-19a, miR-20a, miR-21, miR-92a, and miR-155) in CSF that detect, with high sensitivity, secondary CNS lymphoma involvement in aggressive B-NHL, including DLBCL, MCL, and Burkitt lymphoma. Their combination into an oncomiR index enables the separation of CNS lymphomas from systemic lymphomas or nonmalignant controls with high sensitivity and specificity, and high Receiver Operating Characteristics (DLBCL AUC = 0.96, MCL = 0.93, BL = 1.0). Longitudinal analysis showed that oncomiR levels reflect treatment efficacy and clinical outcomes, allowing their monitoring and prediction. In contrast to conventional methods, CSF oncomiRs enable detection of early and residual CNS involvement, as well as parenchymal involvement. These circulating oncomiRs increase 1–4 months before CNS relapse, allowing its early detection and improving the prediction of CNS relapse risk in DLBCL. Similar effects were detectable, to a lesser extent, in plasma

Internal Jugular Vein Cross-Sectional Area and Cerebrospinal Fluid Pulsatility in the Aqueduct of Sylvius: A Comparative Study between Healthy Subjects and Multiple Sclerosis Patients

Objectives Constricted cerebral venous outflow has been linked with increased cerebrospinal fluid (CSF) pulsatility in the aqueduct of Sylvius in multiple sclerosis (MS) patients and healthy individuals. This study investigates the relationship between CSF pulsatility and internal jugular vein (IJV) cross-sectional area (CSA) in these two groups, something previously unknown. Methods 65 relapsing-remitting MS patients (50.8% female; mean age = 43.8 years) and 74 healthy controls (HCs) (54.1% female; mean age = 43.9 years) were investigated. CSF flow quantification was performed on cine phase-contrast MRI, while IJV-CSA was calculated using magnetic resonance venography. Statistical analysis involved correlation, and partial least squares correlation analysis (PLSCA). Results PLSCA revealed a significant difference (p<0.001; effect size = 1.072) between MS patients and HCs in the positive relationship between CSF pulsatility and IJV-CSA at C5-T1, something not detected at C2-C4. Controlling for age and cardiovascular risk factors, statistical trends were identified in HCs between: increased net positive CSF flow (NPF) and increased IJV-CSA at C5-C6 (left: r = 0.374, p = 0.016; right: r = 0.364, p = 0.019) and C4 (left: r = 0.361, p = 0.020); and increased net negative CSF flow and increased left IJV-CSA at C5-C6 (r = -0.348, p = 0.026) and C4 (r = -0.324, p = 0.039), whereas in MS patients a trend was only identified between increased NPF and increased left IJV-CSA at C5-C6 (r = 0.351, p = 0.021). Overall, correlations were weaker in MS patients (p = 0.015). Conclusions In healthy adults, increased CSF pulsatility is associated with increased IJV-CSA in the lower cervix (independent of age and cardiovascular risk factors), suggesting a biomechanical link between the two. This relationship is altered in MS patients

Endothelin-1 as a neuropeptide: neurotransmitter or neurovascular effects?

Endothelin-1 (ET-1) is an endothelium-derived peptide that also possesses potent mitogenic activity. There is also a suggestion the ET-1 is a neuropeptide, based mainly on its histological identification in both the central and peripheral nervous system in a number of species, including man. A neuropeptide role for ET-1 is supported by studies showing a variety of effects caused following its administration into different regions of the brain and by application to peripheral nerves. In addition there are studies proposing that ET-1 is implicated in a number of neural circuits where its transmitter affects range from a role in pain and temperature control to its action on the hypothalamo-neurosecretory system. While the effect of ET-1 on nerve tissue is beyond doubt, its action on nerve blood flow is often ignored. Here, we review data generated in a number of species and using a variety of experimental models. Studies range from those showing the distribution of ET-1 and its receptors in nerve tissue to those describing numerous neurally-mediated effects of ET-1

Characterization of nanoporous Lanthanide-doped YAG powders obtained by propellant synthesis

In the present work, we explored the possibility of obtaining nanocrystalline powders of lanthanide-doped Y3Al5O12 (YAG, yttrium aluminum garnet) using solution propellant synthesis, a novel technique that has been proven to be capable of producing nanopowders of numerous oxides at relatively low temperatures and in a rapid way. A series of YAG samples containing a number of different trivalent lanthanide ions (Eu, Er, Ho, Tm) was produced. Samples were characterized by X-ray diffraction for phase identification and line broadening analysis, and by electron microscopy (SEM and HRTEM) for morphological and nanostructural investigation. The samples have a polycrystalline porous structure made up of particles in the nanometer range. Crystallites have a high degree of disorder; the ones doped with Eu3+ are characterized by an intense and well-resolved luminescence spectrum in the visible region

Characterization of nanoporous lanthanide-doped YAG powders obtained by propellant synthesis

In the present work, we explored the possibility of obtaining nanocrystalline powders of lanthanide-doped Y3Al5O12 (YAG, yttrium aluminum garnet) using solution propellant synthesis, a novel technique that has been proven to be capable of producing nanopowders of numerous oxides at relatively low temperatures and in a rapid way. A series of YAG samples containing a number of different trivalent lanthanide ions (Eu, Er, Ho, Tm) was produced. Samples were characterized by X-ray diffraction for phase identification and line broadening analysis, and by electron microscopy (SEM and HRTEM) for morphological and nanostructural investigation. The samples have a polycrystalline porous structure made up of particles in the nanometer range. Crystallites have a high degree of disorder; the ones doped with Eu3+ are characterized by an intense and well-resolved luminescence spectrum in the visible region

Characterization of nanoporous Lanthanide-doped YAG powders obtained by propellant synthesis

In the present work, we explored the possibility of obtaining nanocrystalline powders of lanthanide-doped Y3Al5O12 (YAG, yttrium aluminum garnet) using solution propellant synthesis, a novel technique that has been proven to be capable of producing nanopowders of numerous oxides at relatively low temperatures and in a rapid way. A series of YAG samples containing a number of different trivalent lanthanide ions (Eu, Er, Ho, Tm) was produced. Samples were characterized by X-ray diffraction for phase identification and line broadening analysis, and by electron microscopy (SEM and HRTEM) for morphological and nanostructural investigation. The samples have a polycrystalline porous structure made up of particles in the nanometer range. Crystallites have a high degree of disorder; the ones doped with Eu3+ are characterized by an intense and well-resolved luminescence spectrum in the visible region

The activation of inactive membrane-associated protein kinase C is associated with DMSO-induced erythroleukemia cell differentiation

NRC publication: Ye

Engineered α-hemolysin pores with chemically and genetically-fused functional proteins

Protein engineering could be used to bring two proteins together, which don't normally interact, in an oriented configuration. Using computer modelling and experimental work involving mutagenesis, a new dimer complex, (α7)2, was engineered with two α-hemolysin (αHL) heptamers (α7) units linked via disulfide bridges in a cap-to-cap orientation. The structure of (α7)2 was confirmed by biochemical analysis, transmission electron microscopy (TEM) and single-channel electrical recording. Importantly, it was shown that the one of two transmembrane  barrels of (α7)2 can insert into an attoliter liposome, while the other spans a planar lipid bilayer. (α7)2 pores spanning two bilayers were also observed by TEM. In potential, (α7)2 could be used for small molecule transfer between micron-sized vesicles (minimal cells) and would have applications in forming proto-tissues from minimal cells. Another target has been to couple a highly processive exonuclease, λ-exonuclease (λ-exo), which functions as a trimer, with the α7 pore for DNA sequencing and single molecule studies of λ-exo. Several genetic fusion constructs of λ-exo and αHL were screened and optimized for activity. By linking the N-terminus of λ-exo monomer to the C-terminus of the αHL monomer (α1), a new kind of processive exonuclease (AE) was synthesized that can form pores in bilayers. AE and wild-type α1 could be integrated into hetero-heptamers with different number of AE subunits. To achieve a hetero-heptamer with only one λ-exo trimer molecule mounted on the αHL cap, a concatemer of 2 λ-exo (exo3) was made by genetically linking the monomers of λ-exo with 15 and 17 amino acid linkers. The immediate next step is to link exo3 to α1 and then to co-assemble the exo3-α1 fusion construct with α1 to make the λ-exo-αHL pore complex. Using similar strategies as described in this thesis, other proteins could be linked to αHL increasing the scope of the nanopore technology.EThOS - Electronic Theses Online ServiceGBUnited Kingdo