Space-time coupling in the up-conversion of broadband down-converted light

We investigate the up-conversion process of broadband light from parametric down-conversion (PDC), focusing on the spatio-temporal spectral properties of the sum-frequency generated (SFG) radiation. We demonstrate that the incoherent component of the SFG spectrum is characterized by a skewed geometry in space-time, which originates from a compensation between the group-velocity mismatch and the spatial walk-off of the fundamental and the SFG fields. The results are illustrated both by a theoretical modeling of the optical system and by experimental measurements.Comment: 11 pages, 9 figures. arXiv admin note: text overlap with arXiv:1308.236

A case of acanthosis nigricans in a HIV-infected patient

Background: To date, very little information is available concerning the relationship between acanthosis nigricans (AN) and infection with human immunodeficiency virus type 1 (HIV-1). Case presentation: Herein, we report the case of a middle-aged man admitted for fever and progressively worsening dyspnea in the context of an opportunistic pneumonia and firstly diagnosed with acquired immunodeficiency syndrome (AIDS). At the time of diagnosis, physical examination revealed the presence of a palpable, hyperpigmented skin lesion on the left areola with surface desquamation and velvety texture consistent with AN. Of note, the most common primary etiologies related to AN were excluded and the complete regression of the skin lesion was observed once antiretroviral therapy was started. Conclusion: This is the second report of AN found in patients with AIDS and apparently responsive to prolonged antiretroviral treatment. Possible explanations of this association are still not completely understood, probably related to virus-induced changes in lipid metabolism. Our experience suggests that HIV testing should always be considered in the setting of apparently idiopathic AN

Growth factors and experimental arterial grafts

Background: The production of growth factors from several experimental arterial conduits was determined. Methods: We implanted 105 experimental arterial grafts that were 1 cm long in the abdominal aorta of Lewis rats (average weight, 250 g). Five different types of grafts were analyzed: arterial isografts, vein grafts, arterial allografts, and polytetrafluoroethylene (PTFE) grafts with normal or decreased compliance. Animals were killed humanely 4 weeks after surgery and the production of platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF), transforming growth factor-b, tumor necrosis factor-a, and interleukin-1 was analyzed. Results: Myointimal hyperplasia (MH) was evident in vein grafts, arterial allografts, and PTFE grafts, but not in arterial isografts. Growth factor production was increased for grafts prone to develop MH like vein, PTFE grafts, and arterial allografts. PDGF and bFGF were increased significantly for PTFE and vein grafts, but not for arterial allografts. The importance of bFGF and PGDF was confirmed by the capability of antibody to PDGF and to bFGF to reduce the mitogenic activity of smooth muscle cells, in vivo and in vitro, for PTFE and vein grafts, but not for arterial allografts, in which a predominant role was played by interleukin-1 and tumor necrosis factor-a. Conclusions: Agents able to neutralize this increased production of growth factors, either directly or by competition with their receptors, can prevent MH formation. (J Vasc Surg 2016;64:1444-9.) Clinical Relevance: Arterial grafts release growth factors, which can lead to myointimal hyperplasia formation and atherosclerosis progression in the arterial tree. Both phenomena can cause graft occlusion. Inhibition of growth factor release by arterial grafts can improve their clinical effectiveness

Tinnitus in temporomandibular joint disorders: is it a specific somatosensory tinnitus subtype?

ABSTRACT: The most significant otologic symptoms, consisting of ear pain, tinnitus, dizziness, hearing loss and auricolar "fullness", generally arise within the auditory system, often are associated with extra auricolar disorders, particularly disorder of the temporo-mandibular joint. In our study we examined a sample of 200 consecutive patients who had experienced severe disabling symptom. The patiens came to maxillofacial specialist assessment for temporomandibular disorder. Each patient was assessed by a detailed anamnestic and clinical temporomandibular joint examination and they are divided into five main groups according classification criteria established by Wilkes; tinnitus and subjective indicators of pain are evaluated. The results of this study provide a close correlation between the joint pathology and otologic symptoms, particularly regarding tinnitus and balance disorders, and that this relationship is greater the more advanced is the stage of joint pathology. Moreover, this study shows that TMD-related tinnitus principally affects a younger population (average fifth decade of life) and mainly women (more than 2/3 of the cases). Such evidence suggests the existence of a specific tinnitus subtype that may be defined as "TMD-related somatosensory tinnitus"

NO scavenging through reductive nitrosylation of ferric Mycobacterium tuberculosis and Homo sapiens nitrobindins

Ferric nitrobindins (Nbs) selectively bind NO and catalyze the conversion of peroxynitrite to nitrate. In this study, we show that NO scavenging occurs through the reductive nitrosylation of ferric Mycobacterium tuberculosis and Homo sapiens nitrobindins (Mt-Nb(III) and Hs-Nb(III), respectively). The conversion of Mt-Nb(III) and Hs-Nb(III) to Mt-Nb(II)-NO and Hs-Nb(II)-NO, respectively, is a monophasic process, suggesting that over the explored NO concentration range (between 2.5 × 10-5 and 1.0 × 10-3 M), NO binding is lost in the mixing time (i.e., NOkon ≥ 1.0 × 106 M-1 s-1). The pseudo-first-order rate constant for the reductive nitrosylation of Mt-Nb(III) and Hs-Nb(III) (i.e., k) is not linearly dependent on the NO concentration but tends to level off, with a rate-limiting step (i.e., klim) whose values increase linearly with [OH-]. This indicates that the conversion of Mt-Nb(III) and Hs-Nb(III) to Mt-Nb(II)-NO and Hs-Nb(II)-NO, respectively, is limited by the OH--based catalysis. From the dependence of klim on [OH-], the values of the second-order rate constant kOH- for the reductive nitrosylation of Mt-Nb(III)-NO and Hs-Nb(III)-NO were obtained (4.9 (±0.5) × 103 M-1 s-1 and 6.9 (±0.8) × 103 M-1 s-1, respectively). This process leads to the inactivation of two NO molecules: one being converted to HNO2 and another being tightly bound to the ferrous heme-Fe(II) atom

Strategies to Reverse Endothelial Progenitor Cell Dysfunction in Diabetes

Bone-marrow-derived cells-mediated postnatal vasculogenesis has been reported as the main responsible for the regulation of vascular homeostasis in adults. Since their discovery, endothelial progenitor cells have been depicted as mediators of postnatal vasculogenesis for their peculiar phenotype (partially staminal and partially endothelial), their ability to differentiate in endothelial cell line and to be incorporated into the vessels wall during ischemia/damage. Diabetes mellitus, a condition characterized by cardiovascular disease, nephropathy, and micro- and macroangiopathy, showed a dysfunction of endothelial progenitor cells. Herein, we review the mechanisms involved in diabetes-related dysfunction of endothelial progenitor cells, highlighting how hyperglycemia affects the different steps of endothelial progenitor cells lifetime (i.e., bone marrow mobilization, trafficking into the bloodstream, differentiation in endothelial cells, and homing in damaged tissues/organs). Finally, we review preclinical and clinical strategies that aim to revert diabetes-induced dysfunction of endothelial progenitor cells as a means of finding new strategies to prevent diabetic complications

Effectiveness of cyclosporine and mycophenolate mofetil in a child with refractory evans syndrome

Evans Syndrome is a rare autoimmune disease consisting of hemolytic anemia, thrombocytopenia and/or neutropenia. It may be associated with other autoimmune or lymphoproliferative diseases. Its course can be extremely serious and, rarely, even life-threatening; thus it represents a excellent treatment challenge for the pediatric hematologist. First line treatment consists of steroids and/or immunoglobulin; further therapy with rituximab, vincristine, cyclophosphamide and other immunosuppressive drugs can be considered in unresponsive patients. We describe a baby with refractory Evans Syndrome that was cured by prolonged administration of mycophenolate mofetil and remained disease-free for 4 years after the discontinuation of treatment

Nonlinear absorption and gain in InGaAs/GaAs quantum wells

We present a detailed study of the excitonic nonlinearities in InGaAs/GaAs multiple quantum wells based on both stationary and transient pump-and-probe transmission spectroscopy. Bleaching of the excitonic resonance and free carrier gain have been observed. A quantitative analysis of the observed nonlinearity is provided by means of a rigorous solution of the Bethe–Salpeter equation for the investigated heterostructures

Tailored sample mounting for light-sheet fluorescence microscopy of clarified specimens by polydimethylsiloxane casting

The combination of biological tissue clearing methods with light-sheet fluorescence microscopy (LSFM) allows acquiring images of specific biological structures of interest at whole organ scale and microscopic resolution. Differently to classical epifluorescence techniques, where the sample is cut into slices, LSFM preserves the whole organ architecture, which is of particular relevance for investigations of long-range neuronal circuits. This imaging modality comes with the need of new protocols for sample mounting. Gel matrix, hooks, tips, glues, and quartz cuvettes have been used to keep whole rodent organs in place during image acquisitions. The last one has the advantage of avoiding sample damage and optical aberrations when using a quartz refractive index (RI) matching solution. However, commercially available quartz cuvettes for such large samples are expensive. We propose the use of polydimethylsiloxane (PDMS) for creating tailor-made cuvettes for sample holding. For validation, we compared PDMS and quartz cuvettes by measuring light transmittance and performing whole mouse-brain imaging with LSFM. Moreover, imaging can be performed using an inexpensive RI matching solution, which further reduces the cost of the imaging process. Worth of note, the RI matching solution used in combination with PDMS leads to a moderate expansion of the sample with respect to its original size, which may represent an advantage when investigating small components, such as neuronal processes. Overall, we found the use of custom-made PDMS cuvettes advantageous in term of cost, image quality, or preservation of sample integrity with respect to other whole-mouse brain mounting strategies adopted for LSFM

Efficient District Heating in a Decarbonisation Perspective: A Case Study in Italy

The European and national regulations in the decarbonisation path towards 2050 promote district heating in achieving the goals of efficiency, energy sustainability, use of renewables, and reduction of fossil fuel use. Improved management and optimisation, use of RES, and waste heat/cold sources decrease the overall demand for primary energy, a condition that is further supported by building renovations and new construction of under (almost) zero energy buildings, with a foreseeable decrease in the temperature of domestic heating systems. Models for the simulation of efficient thermal networks were implemented and described in this paper, together with results from a real case study in Italy, i.e., University Campus of Parma. Activities include the creation and validation of calculation codes and specific models in the Modelica language (Dymola software), aimed at investigating stationary regimes and dynamic behaviour as well. An indirect heat exchange substation was coupled with a resistive-capacitive model, which describes the building behaviour and the thermal exchanges by the use of thermos-physical parameters. To optimise indoor comfort conditions and minimise consumption, dynamic simulations were carried out for different operating sets: modulating the supply temperature in the plant depending on external conditions (Scenario 4) decreases the supplied thermal energy (-2.34%) and heat losses (-8.91%), even if a lower temperature level results in higher electricity consumption for pumping (+12.96%), the total energy consumption is reduced by 1.41%. A simulation of the entire heating season was performed for the optimised scenario, combining benefits from turning off the supply in the case of no thermal demand (Scenario 3) and from the modulation of the supply temperature (Scenario 4), resulting in lower energy consumption (the thermal energy supplied by the power plant -3.54%, pumping +7.76%), operating costs (-2.40), and emissions (-3.02%). The energy balance ex-ante and ex-post deep renovation in a single user was then assessed, showing how lowering the network operating temperature at 55 degrees C decreases the supplied thermal energy (-22.38%) and heat losses (-22.11%) with a slightly higher pumping consumption (+3.28%), while maintaining good comfort conditions. These promising results are useful for evaluating the application of low-temperature operations to the existing district heating networks, especially for large interventions of building renovation, and confirm their potential contribution to the energy efficiency targets