Bismuth incorporation and the role of ordering in GaAsBi/GaAs structures

The structure and composition of single GaAsBi/GaAs epilayers grown by molecular beam epitaxy were investigated by optical and transmission electron microscopy techniques. Firstly, the GaAsBi layers exhibit two distinct regions and a varying Bi composition profile in the growth direction. In the lower (25 nm) region, the Bi content decays exponentially from an initial maximum value, while the upper region comprises an almost constant Bi content until the end of the layer. Secondly, despite the relatively low Bi content, CuPtB-type ordering was observed both in electron diffraction patterns and in fast Fourier transform reconstructions from high-resolution transmission electron microscopy images. The estimation of the long-range ordering parameter and the development of ordering maps by using geometrical phase algorithms indicate a direct connection between the solubility of Bi and the amount of ordering. The occurrence of both phase separation and atomic ordering has a significant effect on the optical properties of these layers

Completeness of evanescent modes in layered dielectrics

In the presence of a dielectric slab, the modes of the free electromagnetic field comprise traveling modes, consisting of incoming, reflected, and transmitted parts, as well as trapped modes that are subject to repeated total internal reflection and emerge as evanescent field outside the slab. Traveling modes have a continuous range of frequencies, but trapped modes occur only at certain discrete frequencies. We solve the problem of which relative weight to use when summing over all modes, as commonly required in perturbative calculations. We demonstrate the correctness of our method by showing the completeness of electromagnetic field modes in the presence of a dielectric slab. We derive a convenient method of summing over all modes by means of a single contour integral, which is very useful in standard quantum electrodynamic calculations

3D Collaboration Spaces for Enterprise Work: A Thought Leaders’ Dialogue and Conference Summary Paper UPENN Virtual Organizational Dynamics Design Laboratory

On February 8th, 6pm to 10pm Eastern, presenters from CCL’s Innovation Group, IBM’s Center for Advanced Learning (CAL), Stanford’s Project Based Learning Lab (PBL) and Proton Media/PPD 3D joined UPenn’s Virtual OD Design Lab for our first fully immersive 3D Peer learning Conference, hosted and supported by Proton Media in ProtoSphere. In this exciting event, the Lab team engaged thought leaders in real time dialogue about their state-of- the-art cases covering advanced uses of 3D immersive technologies for leadership and organization development, collaboration and global enterprise training

Angiotensin AT1 and AT2 receptors heteromer expression in microglia correlates with Parkinson's disease progression in the hemilesioned rat model of the disease

Background/Aims : The renin-angiotensin system (RAS) is altered in Parkinson's disease (PD), a disease due to substantia nigra neurodegeneration and whose dopamine-replacement therapy, using the precursor levodopa, leads to dyskinesias as the main side effect. Angiotensin AT 1 and AT 2 receptors, mainly known for their role in regulating water homeostasis and blood pressure and able to form heterodimers (AT 1/2 Hets), are present in the central nervous system. We assessed the functionality and expression of AT 1/2 Hets in Parkinson Disease (PD). Methods: Immunocytochemistry was used to analyze the colocalization between angiotensin receptors, bioluminescence resonance energy transfer was used to detect AT 1/2 Hets. Calcium and cAMP determination, MAPK activation and label-free assays were performed to characterize signaling. Proximity ligation assays was used to quantify receptor expression in microglial cells and brain striatal slices. Results: We confirmed that AT 1 and AT 2 receptors form AT 1/2 Hets that are expressed in cells of the central nervous system. AT 1/2 Hets are novel functional units with particular signaling properties. Importantly, the coactivation of the two receptors in the heteromer reduces the signaling output of angiotensin. Remarkably, AT 1/2 Hets that are expressed in both striatal neurons and microglia show a cross-potentiation, i.e. candesartan, the antagonist of AT 1 increases the effect of AT 2 receptor agonists. In addition, the level of expression in the unilateral 6-OH-dopamine lesion rat PD model increases upon disease progression and is maximal in dyskinetic animals. Conclusion: The results indicate that boosting the action of neuroprotective AT 2 receptors using an AT 1 receptor antagonist constitutes a promising therapeutic strategy in PD

Angiotensin AT 1 and AT 2 receptor heteromer expression in the hemilesioned rat model of Parkinson's disease that increases with levodopa-induced dyskinesia

Background/aims: The renin-angiotensin system (RAS) is altered in Parkinson's disease (PD), a disease due to substantia nigra neurodegeneration and whose dopamine-replacement therapy, using the precursor levodopa, leads to dyskinesias as the main side effect. Angiotensin AT1 and AT2 receptors, mainly known for their role in regulating water homeostasis and blood pressure and able to form heterodimers (AT1/2Hets), are present in the central nervous system. We assessed the functionality and expression of AT1/2Hets in Parkinson disease (PD). Methods: Immunocytochemistry was used to analyze the colocalization between angiotensin receptors; bioluminescence resonance energy transfer was used to detect AT1/2Hets. Calcium and cAMP determination, MAPK activation, and label-free assays were performed to characterize signaling in homologous and heterologous systems. Proximity ligation assays were used to quantify receptor expression in mouse primary cultures and in rat striatal sections. Results: We confirmed that AT1 and AT2 receptors form AT1/2Hets that are expressed in cells of the central nervous system. AT1/2Hets are novel functional units with particular signaling properties. Importantly, the coactivation of the two receptors in the heteromer reduces the signaling output of angiotensin. Remarkably, AT1/2Hets that are expressed in both striatal neurons and microglia make possible that candesartan, the antagonist of AT1, increases the effect of AT2 receptor agonists. In addition, the level of striatal expression increased in the unilateral 6-OH-dopamine lesioned rat PD model and was markedly higher in parkinsonian-like animals that did not become dyskinetic upon levodopa chronic administration if compared with expression in those that became dyskinetic. Conclusion: The results indicate that boosting the action of neuroprotective AT2 receptors using an AT1 receptor antagonist constitutes a promising therapeutic strategy in PD. Keywords: Dyskinesia; G-protein-coupled receptor (GPCR); Heteromer; Levodopa; Neuroinflammation

Autologous and Allogeneic Stem Cell Transplantation for Treatment of Crohn’s Fistulae

Up to 20% of patients with Crohn’s disease (CD) may have perianal fistula disease. Classically, surgery has played an important role; in recent years, medical treatment has taken a leading role. Immunosuppressants and biological trea tments have proven beneficial in many patients, but still, the percentage of patients who do not respond remains significant. In this scenario, cell therapy is envisaged as an effective alternative to surgery. The promising preclinical and clinical data that we review below suggest that cell therapy could represent a major advance in the clinical management of this difficult problem

Functional complexes of Angiotensin-converting enzyme 2 and renin-angiotensin system receptors: expression in adult but not fetal lung tissue

Angiotensin-converting enzyme 2 (ACE2) is a membrane peptidase and a componentof the renin-angiotensin system (RAS) that has been found in cells of all organs, including thelungs. While ACE2 has been identified as the receptor for severe acute respiratory syndrome (SARS)coronaviruses, the mechanism underlying cell entry remains unknown. Human immunodeficiencyvirus infects target cells via CXC chemokine receptor 4 (CXCR4)-mediated endocytosis. Furthermore,CXCR4 interacts with dipeptidyl peptidase-4 (CD26/DPPIV), an enzyme that cleaves CXCL12/SDF-1,which is the chemokine that activates this receptor. By analogy, we hypothesized that ACE2 mightalso be capable of interactions with RAS-associated G-protein coupled receptors. Using resonanceenergy transfer and cAMP and mitogen-activated protein kinase signaling assays, we found thathuman ACE2 interacts with RAS-related receptors, namely the angiotensin II type 1 receptor (AT1R),the angiotensin II type 2 receptor (AT2R), and the MAS1 oncogene receptor (MasR). Although theseinteractions led to various alterations of signal transduction, but, more importantly, ligand binding toAT1R resulted in the downregulation of ACE2 cell surface expression, while ligand binding to AT2R,but not to MasR, resulted in upregulation of ACE2 cell surface expression. Proximity ligation assaysperformed in situ revealed macromolecular complexes containing ACE2 and AT1R, AT2R or MasR inadult but not fetal mouse lung tissue. These findings highlight the relevance of RAS in SARS-CoV-2infection and the role of ACE2-containing complexes as potential therapeutic targets

Synthesis and Structural Characterization of Branched Bimetallic AuPd Nanoparticles with a Highly Tunable Optical Response

Bimetallic nanostructures composed of gold (Au) and palladium (Pd) have garnered increased interest for their applications in heterogeneous catalysis. This study reports a simple strategy for manufacturing Au@Pd bimetallic branched nanoparticles (NPs), which offer a tunable optical response, using polyallylamine-stabilized branched AuNPs as template cores for Pd overgrowth. The palladium content can be altered by manipulating the concentration of PdCl4 2− and ascorbic acid (AA) that are injected, which permit an overgrowth of the Pd shell up to ca. 2 nm thick. The homogeneous distribution of Pd at the surfaces of Au NPs can be carried out regardless of their size or branching degree, which allows for an adjustment of the plasmon response in the near-infrared (NIR) spectral range. As a proof of concept, the nanoenzymatic activity of pure gold and gold−palladium NPs was compared, exploring their peroxidase-like activity in the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB). The bimetallic AuPd NPs demonstrate an increase in the catalytic properties attributed to the presence of palladium at the surface of gold

Peripheral giant cells granuloma as a rare early manifestation of primary hyperparathyroidism

Primary hyperparathyroidism occurs due to parathyroid adenoma, which as initial presentation in most cases includes recurrent nephrolithiasis (10-25%). Giant cell tumors (GDD) also called osteoclastomas or brown tumors affect the second decade of life and are currently a rare manifestation of primary hyperthyroidism. The incidence of lesion appearance in the maxillary bones is 4.5%. We presented the case of a 36 year old female patient with history of hypertension, who developed an increase in volume in the right maxillary region of 4×3 cm, with incapability of complete occlusion of dental arch, solid dysphagia, biopsy was performed with peripheral giant cells granuloma as a result, PTH serum levels were requested, with result of 1175 pg/ml and serum calcium of 13.24 mg/dl. Parathyroid gammagram was performed with hyperfunctioning parathyroid tissue. Patient underwent a selective parathyroidectomy. She had an adequate postoperative evolution and was discharged without complications. The patient had adequate follow up by head and neck surgery in external consultation, serum calcium 7.66 mg/dl, decrease of volume in right maxillary region to 3×3 cm; pathology report with parathyroid adenoma. Surgical treatment of brown tumor is still pending by the maxillofacial surgery department

Laser-Assisted Production of Carbon-Encapsulated Pt-Co Alloy Nanoparticles for Preferential Oxidation of Carbon Monoxide

C-encapsulated highly pure PtxCoy alloy nanoparticles have been synthesized by an innovative one-step in-situ laser pyrolysis. The obtained X-ray diffraction pattern and transmission electron microscopy images correspond to PtxCoy alloy nanoparticles with average diameters of 2.4 nm and well-established crystalline structure. The synthesized PtxCoy/C catalyst containing 1.5 wt% of PtxCoy nanoparticles can achieve complete CO conversion in the temperature range 125–175°C working at weight hourly space velocities (WHSV) of 30 L h−1g−1. This study shows the first example of bimetallic nanoalloys synthesized by laser pyrolysis and paves the way for a wide variety of potential applications and metal combinations