280 research outputs found
Continuous Generative Neural Networks
In this work, we present and study Continuous Generative Neural Networks
(CGNNs), namely, generative models in the continuous setting: the output of a
CGNN belongs to an infinite-dimensional function space. The architecture is
inspired by DCGAN, with one fully connected layer, several convolutional layers
and nonlinear activation functions. In the continuous setting, the
dimensions of the spaces of each layer are replaced by the scales of a
multiresolution analysis of a compactly supported wavelet. We present
conditions on the convolutional filters and on the nonlinearity that guarantee
that a CGNN is injective. This theory finds applications to inverse problems,
and allows for deriving Lipschitz stability estimates for (possibly nonlinear)
infinite-dimensional inverse problems with unknowns belonging to the manifold
generated by a CGNN. Several numerical simulations, including signal
deblurring, illustrate and validate this approach.Comment: 40 pages, 8 figure
Hepatic steatosis in hepatitis C is a storage disease due to HCV interaction with microsomal triglyceride transfer protein (MTP)
Liver steatosis is a frequent histological feature in patients chronically infected with hepatitis C virus (HCV). The relationship between HCV and hepatic steatosis seems to be the result of both epigenetic and genetic factors. In vivo and in vitro studies have shown that HCV can alter intrahepatic lipid metabolism by affecting lipid synthesis, oxidative stress, lipid peroxidation, insulin resistance and the assembly and secretion of VLDL. Many studies suggest that HCV-related steatosis might be the result of a direct interaction between the virus and MTP. It has been demonstrated that MTP is critical for the secretion of HCV particles and that inhibition of its lipid transfer activity reduces HCV production. However, higher degrees of hepatic steatosis were found in chronic hepatitis C patients carrying the T allele of MTP -493G/T polymorphism that seems to be associated with increased MTP transcription. We propose here that liver steatosis in hepatitis C could be a storage disease induced by the effects of the virus and of its proteins on the intracellular lipid machinery and on MTP. Available data support the hypothesis that HCV may modulate MTP expression and activity through a number of mechanisms such as inhibition of its activity and transcriptional control. Initial up regulation could favour propagation of HCV while down regulation in chronic phase could cause impairment of triglyceride secretion and excessive lipid accumulation, with abnormal lipid droplets facilitating the "storage" of virus particles for persistent infection
Manifold Learning by Mixture Models of VAEs for Inverse Problems
Representing a manifold of very high-dimensional data with generative models
has been shown to be computationally efficient in practice. However, this
requires that the data manifold admits a global parameterization. In order to
represent manifolds of arbitrary topology, we propose to learn a mixture model
of variational autoencoders. Here, every encoder-decoder pair represents one
chart of a manifold. We propose a loss function for maximum likelihood
estimation of the model weights and choose an architecture that provides us the
analytical expression of the charts and of their inverses. Once the manifold is
learned, we use it for solving inverse problems by minimizing a data fidelity
term restricted to the learned manifold. To solve the arising minimization
problem we propose a Riemannian gradient descent algorithm on the learned
manifold. We demonstrate the performance of our method for low-dimensional toy
examples as well as for deblurring and electrical impedance tomography on
certain image manifolds
Indocyanine green (ICG) fluorescent cholangiography during laparoscopic cholecystectomy using RUBINAâą technology: preliminary experience in two pediatric surgery centers
Background Recently, we reported the feasibility of indocyanine green (ICG) near-infrared fluorescence (NIRF) imaging to identify extrahepatic biliary anatomy during laparoscopic cholecystectomy (LC) in pediatric patients. This paper aimed to describe the use of a new technology, RUBINA (TM), to perform intra-operative ICG fluorescent cholangiography (FC) in pediatric LC. Methods During the last year, ICG-FC was performed during LC using the new technology RUBINA (TM) in two pediatric surgery units. The ICG dosage was 0.35 mg/Kg and the median timing of administration was 15.6 h prior to surgery. Patient baseline, intra-operative details, rate of biliary anatomy identification, utilization ease, and surgical outcomes were assessed. Results Thirteen patients (11 girls), with median age at surgery of 12.9 years, underwent LC using the new RUBINA (TM) technology. Six patients (46.1%) had associated comorbidities and five (38.5%) were practicing drug therapy. Pre-operative workup included ultrasound (n = 13) and cholangio-MRI (n = 5), excluding biliary and/or vascular anatomical anomalies. One patient needed conversion to open surgery and was excluded from the study. The median operative time was 96.9 min (range 55-180). Technical failure of intra-operative ICG-NIRF visualization occurred in 2/12 patients (16.7%). In the other cases, ICG-NIRF allowed to identify biliary/vascular anatomic anomalies in 4/12 (33.3%), including Moynihan's hump of the right hepatic artery (n = 1), supravescicular bile duct (n = 1), and short cystic duct (n = 2). No allergic or adverse reactions to ICG, post-operative complications, or reoperations were reported. Conclusion Our preliminary experience suggested that the new RUBINA (TM) technology was very effective to perform ICG-FC during LC in pediatric patients. The advantages of this technology include the possibility to overlay the ICG-NIRF data onto the standard white light image and provide surgeons a constant fluorescence imaging of the target anatomy to assess position of critical biliary structures or presence of anatomical anomalies and safely perform the operation
The recombinant cysteine proteinase B (CPB) from Leishmania braziliensis and its domains: promising antigens for serodiagnosis of cutaneous and visceral leishmaniasis in dogs.
Leishmaniasis represents a group of parasitic diseases caused by a protozoan of the genus Leishmania and is widely distributed in tropical and subtropical regions. Leishmaniasis is one of the major tropical neglected diseases, with 1.5 to 2 million new cases occurring annually. Diagnosis remains a challenge despite advances in parasitological, serological, and molecular methods. Dogs are an important host for the parasite and develop both visceral and cutaneous lesions. Our goal was to contribute to the diagnosis of canine cutaneous leishmaniasis (CL) and visceral leishmaniasis (VL) using the recombinant cysteine proteinase B (F-CPB) from Leishmania braziliensis and its N- and C-terminal domains (N-CPB and C-CPB) as antigens in an enzyme-linked immunosorbent assay (ELISA). Sera from dogs from Northwest Argentina diagnosed with CL were tested by ELISA against a supernatant of L. braziliensis lysate, the F-CPB protein, and its domains. We found values of sensitivity (Se) of 90.7%, 94.4%, and 94.3% and specificity (Sp) of 95.5%, 90.9%, and 91.3% for F-CPB and its N- and C-terminal domains, respectively. In sera from dogs diagnosed with VL from Northeast Argentina, we found Se of 93.3%, 73.3%, and 66.7% and Sp of 92.3%, 76.9%, and 88.5% for F-CPB and its N- and C-terminal domains, respectively. These results support CPB as a relevant antigen for canine leishmaniasis diagnosis in its different clinical presentations. More interestingly, the amino acid sequence of CPB showed high percentages of identity in several Leishmania species, suggesting that the CPB from L. braziliensis qualifies as a good antigen for the diagnosis of leishmaniasis caused by different species.Fil: Bivona, Augusto Ernesto. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Investigaciones en MicrobiologĂa y ParasitologĂa MĂ©dica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en MicrobiologĂa y ParasitologĂa MĂ©dica; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; ArgentinaFil: Czentner Colomo, Lucas. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Investigaciones en MicrobiologĂa y ParasitologĂa MĂ©dica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en MicrobiologĂa y ParasitologĂa MĂ©dica; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; ArgentinaFil: Sanchez Alberti, AndrĂ©s. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Investigaciones en MicrobiologĂa y ParasitologĂa MĂ©dica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en MicrobiologĂa y ParasitologĂa MĂ©dica; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; ArgentinaFil: Cerny, Natacha. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Investigaciones en MicrobiologĂa y ParasitologĂa MĂ©dica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en MicrobiologĂa y ParasitologĂa MĂ©dica; ArgentinaFil: Cardoso Landaburu, Alejandro Cesar. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Investigaciones en MicrobiologĂa y ParasitologĂa MĂ©dica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en MicrobiologĂa y ParasitologĂa MĂ©dica; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; ArgentinaFil: Nevot, MarĂa Cecilia. Veterinaria del Oeste; ArgentinaFil: Estevez, JosĂ© Octavio. Veterinaria del Oeste; ArgentinaFil: Marco, Jorge Diego. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Salta. Instituto de PatologĂa Experimental. Universidad Nacional de Salta. Facultad de Ciencias de la Salud. Instituto de PatologĂa Experimental; ArgentinaFil: BasombrĂo, Manuel Alberto. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Salta. Instituto de PatologĂa Experimental. Universidad Nacional de Salta. Facultad de Ciencias de la Salud. Instituto de PatologĂa Experimental; ArgentinaFil: Malchiodi, Emilio Luis. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Investigaciones en MicrobiologĂa y ParasitologĂa MĂ©dica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en MicrobiologĂa y ParasitologĂa MĂ©dica; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; ArgentinaFil: Cazorla, Silvia Ines. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Investigaciones en MicrobiologĂa y ParasitologĂa MĂ©dica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en MicrobiologĂa y ParasitologĂa MĂ©dica; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - TucumĂĄn. Centro de Referencia para Lactobacilos; Argentin
Cancer cell death induced by ferritins and the peculiar role of their labile iron pool
This research was funded by MIUR (PRIN 2012 code 2012SK7ASN). SA and SGC acknowledge the European Unionâs Horizon 2020 research and innovation programme under grant agreement No 668119 (project âIDentIFYâ), SC the postdoctoral grant by Fondazione Cassa di Risparmio di Firenze (n°2013.0494) provided by FiorGen.Peer reviewedPublisher PD
Identification and analysis of a nickel-inducible cation diffusion facilitator-NiCoT combined system in Rhizobium leguminosarum bv. viciae
Nickel, like other transition metals, can be toxic to cells even at moderate concentration (low microM range) by displacing essential metals from their native binding sites or by generating reactive oxygen species that cause oxidative DNA damage. For this reason, cells have evolved mechanisms to deal with excess nickel. Efflux systems include members of the Resistance-Nodulation-cell Division (RND) protein family, P-type ATPases, cation diffusion
facilitators (CDF) and other resistance factors. Nickel-specific exporters have been characterized in Cupravidus metallidurans, Helicobacter pylori, Achromobacter xylosoxidans, Serratia marcenses and Escherichia coli
Enhancement of TiO2 NPs Activity by Fe3O4 Nano-Seeds for Removal of Organic Pollutants in Water
The enhancement of the photocatalytic activity of TiO2 nanoparticles (NPs), synthesized
in the presence of a very small amount of magnetite (Fe3O4) nanoparticles, is here presented
and discussed. From X-ray diffraction (XRD) and differential scanning calorimetry (DSC)
analyses, the crystallinity of TiO2 nanoparticles (NPs) seems to be affected by Fe3O4, acting as
nano-seeds to improve the tetragonal TiO2 anatase structure with respect to the amorphous one.
Photocatalytic activity data, i.e., the degradation of methylene blue and the Ofloxacin fluoroquinolone
emerging pollutant, give evidence that the increased crystalline structure of the NPs, even if correlated
to a reduced surface to mass ratio (with respect to commercial TiO2 NPs), enhances the performance of
this type of catalyst. The achievement of a relatively well-defined crystal structure at low temperatures
(Tmax = 150 \u25e6C), preventing the sintering of the TiO2 NPs and, thus, preserving the high density of
active sites, seems to be the keystone to understand the obtained results
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