144 research outputs found

    Pseudo-fermions in an electronic loss-gain circuit

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    In some recent papers a loss-gain electronic circuit has been introduced and analyzed within the context of PT-quantum mechanics. In this paper we show that this circuit can be analyzed using the formalism of the so-called pseudo-fermions. In particular we discuss the time behavior of the circuit, and we construct two biorthogonal bases associated to the Liouville matrix \Lc used in the treatment of the dynamics. We relate these bases to \Lc and \Lc^\dagger, and we also show that a self-adjoint Liouville-like operator could be introduced in the game. Finally, we describe the time evolution of the circuit in an {\em Heisenberg-like} representation, driven by a non self-adjoint hamiltonian.Comment: International Journal of Theoretical Physics, in pres

    Expander selection for an on board ORC energy recovery system

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    This paper deals with the comparison between volumetric expanders (screw, scroll and rotary vane) and an Inlet Forward Radial (IFR) micro turbine for the exploitation of an on board Organic Rankine Cycle (ORC) energy recovery system. The sensible heat recovered from a common bus engine (typically 8000cc) feeds the energy recovery system that can generate sufficient extra power to sustain the air-conditioning system and part of the auxiliaries. The concept is suitable for all kind of thermally propelled vehicles, but the application considered here is specific for an urban bus. The ORC cycle performance is calculated by a Process Simulator (CAMEL Pro) and the results are discussed. A preliminary design of the considered expanders is proposed using ad-hoc made models implemented in MATLAB; the technical constraints inherent to each machine are listed in order to perform the optimal choice of the expander based on efficiency, reliability and power density. Last step will be the selection of the expander that suites the specific technical and design requests. The final choice relapsed on the screw motor, for it is the best compromise in terms of efficiency, lubrication and reliability

    Cues to opening mechanisms from in silico electric field excitation of cx26 hemichannel and in vitro mutagenesis studies in HeLa transfectans

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    Connexin channels play numerous essential roles in virtually every organ by mediating solute exchange between adjacent cells, or between cytoplasm and extracellular milieu. Our understanding of the structure-function relationship of connexin channels relies on X-ray crystallographic data for human connexin 26 (hCx26) intercellular gap junction channels. Comparison of experimental data and molecular dynamics simulations suggests that the published structures represent neither fully-open nor closed configurations. To facilitate the search for alternative stable configurations, we developed a coarse grained (CG) molecular model of the hCx26 hemichannel and studied its responses to external electric fields. When challenged by a field of 0.06 V/nm, the hemichannel relaxed toward a novel configuration characterized by a widened pore and an increased bending of the second transmembrane helix (TM2) at the level of the conserved Pro87. A point mutation that inhibited such transition in our simulations impeded hemichannel opening in electrophysiology and dye uptake experiments conducted on HeLa tranfectants. These results suggest that the hCx26 hemichannel uses a global degree of freedom to transit between different configuration states, which may be shared among the whole connexin family

    Ultrasonographic aspects of the gallbladder mucocele in 30 dogs: retrospective study

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    A mucocele biliar caracteriza-se pela hiperplasia do epitélio da vesícula biliar, aumento da produção de muco, acúmulo e densificação do conteúdo biliar, podendo levar à obstrução, necrose e ruptura da parede da vesícula biliar. Seu achado pode ser acidental ou estar relacionado à sintomatologia. Foi realizado um estudo retrospectivo (2016-2019) a partir de exames ultrassonográficos abdominais em cães, correlacionando os aspectos da vesícula biliar na mucocele, com comorbidades existentes. Foram avaliados 30 cães com diagnóstico de mucocele biliar, dos quais 46,66% apresentaram a doença em estágio inicial e 53,33% demonstraram estágio mais avançado. Destes, 66,66% tinham endocrinopatias, principalmente hiperadrenocorticismo. Sinais de obstrução de vias biliares extra-hepáticas e peritonite biliar foram observados em dois animais. Por seu potencial risco de complicação, avaliações ultrassonográficas de seguimento são indicadas nos casos de tratamento clínico, não se descartando a necessidade de intervenção cirúrgica.Gallbladder mucocele is characterized by hyperplasia of the gallbladder epithelium, increased mucus production, accumulation, and densification of the bile content, which can lead to biliary obstruction, necrosis, and rupture of the gallbladder wall. Its finding may be accidental or related to symptoms. A retrospective study (2016-2019) was carried out based on abdominal ultrasound examinations in dogs, correlating aspects of the gallbladder and biliary system in the mucocele with existing comorbidities. Thirty dogs diagnosed with biliary mucocele were evaluated, of which 46.66% had the disease at an early stage, and 53.33% showed a more advanced stage. Of these, 66.66% were related to endocrinopathies and hyperadrenocorticism. Signs of extrahepatic bile duct obstruction and biliary peritonitis were observed in two animals. Due to their potential risk of complications, follow-up ultrasound assessments are indicated in cases that opt for clinical treatment, not excluding the need for surgical intervention

    Partial Obstruction and Intestinal Bleeding Secondary to a Congenital Duodenal Diverticulum in a Dog

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    Background: Intestinal diverticulum is an abnormality resulting in the formation of a blind-ended saccular pouch that can be acquired either congenital, true (involving all intestinal layers) or false (involving the mucosa and submucosa), with extraluminal and intraluminal type. In humans, the acquired is more frequent, being the colon is the most affected segment followed by duodenum; most of duodenal diverticulum remains asymptomatic, but biliary obstruction, recurrent acute pancreatitis, hemorrhagic ulcer, proximal intestinal obstruction and perforation may occur. The aim of this report is to present a case of a congenital disease in dogs, prone to misdiagnosis due to non-specific clinical signs.Case: An 8-month-old male Boxer was evaluated due to recurrent hyporexia, vomiting, melena and syncope over three months with signs of a possible intestinal obstruction. Physical examination showed no abnormalities except for pale mucous membranes. Complete blood count revealed anemia and leukocytosis. Platelets and biochemical profiles were normal. Abdominal ultrasound examination indicated a dilated duodenum, measuring approximately 3.36 cm in diameter, with heterogeneous fluid content and hyperechogenic structures with acoustic shadow, peristalsis appeared decreased and non-progressive. The gastrointestinal positive contrast study was performed to better evaluate abnormalities detected at ultrasonography. Images after 30 m of contrast administration demonstrated a marked distension of the duodenum, filled with contrast and a mildly filled stomach displaced to the left. Sixty min after contrast administration a marked distension of the entire duodenum, with tortuous aspect and filled with contrast was seen. The caudal duodenal flexure was connected to a large barium filled saccular structure that measured approximately 7 cm in diameter, consistent with a duodenal diverticulum. A blood transfusion was performed and surgical treatment indicated. The diverticulum and a small portion of the caudal duodenal segment were resected, an end-side enteroanastomosis was made due to the difference in diameter between intestinal segments. The patient was medicated with sucralfate (12.5 mg/kg), ranitidine (2 mg/kg), metronidazole (25 mg/kg), dipyrone (25 mg/kg) and, tramadol (2 mg/kg) and recovered quickly from surgery. Histopathological examination characterized the diverticular tissue as a true diverticulum by the presence of all intestinal layers. Post-operative and follow-up evaluations showed no recurrence of clinical signs.Discussion: In veterinary practice, congenital duodenal diverticulum is a rare condition documented in dogs, curiously all Boxers None of the reported cases in literature had the diagnostic of duodenal diverticulum made exclusively by ultrasonography. Other diagnostic imaging modalities, such as gastrointestinal barium study or endoscopy, were necessary. In one case a diagnostic was made during exploratory laparotomy. The marked dilatation of the duodenal segment impaired ultrasound evaluation, allowing recognition of an obstructive pattern, not the diverticulum itself. At histopathological examination, the diverticular tissue was characterized by a thickened wall with a hypertrophied muscle layer, characterizing a true duodenal diverticulum. The location, breed and age of the dogs affected with duodenal diverticulum was similar in all veterinary cases reported. Dogs presenting signs of gastrointestinal disease and abdominal pain are common in patients referred to ultrasound examination. However, despite the rare reports described, we must consider this affection as a differential diagnosis, whenever boxer puppies present these clinical signs associated with gastrointestinal bleeding and syncope

    Polyclonal and monoclonal B lymphocytes response in HCV-infected patients treated with direct-acting antiviral agents

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    Hepatitis C virus (HCV) chronic infection can be associated with extrahepatic manifestations such as mixed cryoglobulinaemia and lymphoproliferative disorders that are endowed with increased rates of morbidity and all-cause mortality. In this study, we used flow cytometry to evaluate the effect of interferon-free antiviral treatment on peripheral blood lymphocytes in HCV-infected patients with or without associated lymphoproliferative disorders. Flow cytometry analysis of peripheral blood lymphocytes was performed at baseline and at the end of treatment. In HCV-infected patients with lymphoproliferative disorders, we evaluated immunoglobulin (Ig) light chain \u3ba/\u3bb ratio variations as a measure of monoclonal B-cell response to antiviral therapy. Healthy volunteers were enrolled as controls. A total of 29 patients were included, nine with and 20 without lymphoproliferative disorders. Sustained virological response was achieved in 29 of 29 patients. We observed a significant reduction in the B-cell compartment (39% global reduction) in eight of nine HCV-infected patients with lymphoproliferative disorders after viral clearance. We recognized the same trend, even if less pronounced, in HCV-infected patients without lymphoproliferative disorders (9% global reduction). Among HCV-infected patients with lymphoproliferative disorders, three showed an improvement/normalization of the immunoglobulin light chain ratio, whereas in the remaining six patients monoclonal B cells persisted to be clonally restricted even 1\ua0year after the end of treatment. Our data show that DAAs treatment can be effective in reducing the frequency of pathological B cells in the peripheral blood of HCV-infected patients affected by HCV-associated lymphoproliferative disorders; however, monoclonal populations can persist after viral eradication

    A model of N-terminal Cyclin T1 based on FRET experiments

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    Human Cyclin T1 is the cyclin partner of kinase CDK9 in the positive transcription elongation factor b (P-TEFb). P-TEFb is recruited by Tat, the transactivator of the human immunodeficiency virus type 1 (HIV-1), to the viral promoter by direct interactions between Tat, Cyclin T1 and thecis-acting transactivation-responsive region (TAR) present at the 5′-end of each viral mRNA. At present, no structural data for Cyclin T1 are available. Here, we build a structural model of an N-terminus portion of Cyclin T1 (aa 27–263) based on the X-ray structure of Cyclin H. The model is compared with site directed mutagenesis data from the literature and validated by fluorescence resonance energy transfer (FRET) using Tat as a probe in living cells. This model provides a first step towards the structural characterization of the CDK9–CycT1–Tat-TAR complex, which is crucial for HIV-1 replication and may constitute a promising target for pharmaceutical intervention

    Modeling and Optimizing Biocontrol in Wines: pH as a Modulator of Yeast Amensalism Interaction

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    The control of spoilage yeasts in wines is crucial to avoid organoleptic deviations in wine production. Traditionally, sulfur dioxide (SO2) was used to control them; nevertheless, SO2 influence on human health and its use is criticized. Biocontrol emerges as an alternative in wine pre-fermentation, but there is limited development in its applicability. Managing kinetics is relevant in the microbial interaction process. pH was identified as a factor affecting the interaction kinetics of Wickerhamomyces anomalus killer biocontrol on Zygosaccharomyces rouxii. Mathematical modeling allows insight into offline parameters and the influence of physicochemical factors in the environment. Incorporating submodels that explain manipulable factors (pH), the process can be optimized to achieve the best-desired outcomes. The aim of this study was to model and optimize, using a constant and a variable pH profile, the interaction of killer biocontrol W. anomalus vs. Z. rouxii to reduce the spoilage population in pre-fermentation. The evaluated biocontrol was W. anomalus against the spoilage yeast Z. rouxii in wines. The kinetic interactions of yeasts were studied at different pH levels maintained constant over time. The improved RamĂłn-Portugal model was adopted using the AMIGO2 toolbox for Matlab. A static optimization of a constant pH profile was performed using the Monte Carlo method, and a dynamic optimization was carried out using a method based on Fourier series and orthogonal polynomials. The model fit with an adjusted R2 of 0.76. Parametric analyses were consistent with the model behavior. Variable vs. constant optimization achieved a lower initial spoilage population peak (99% less) and reached a lower final population (99% less) in a reduced time (100 vs. 140 h). These findings reveal that control with a variable profile would allow an early sequential inoculation of S. cerevisiae. The models explained parameters that are difficult to quantify, such as general inhibitor concentration and toxin concentration. Also, the models indicate higher biocontrol efficiency parameters, such as toxin emission or sensitivity to it, and lower fitness of the contaminant, at pH levels above 3.7 during biocontrol. From a technological standpoint, the study highlights the importance of handling variable profiles in the controller associated with the pH management actuators in the process without incurring additional costs.Fil: Kuchen, BenjamĂ­n. Universidad Nacional de San Juan. Facultad de IngenierĂ­a. Instituto de BiotecnologĂ­a; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - San Juan; ArgentinaFil: Groff, Maria Carla. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - San Juan; Argentina. Universidad Nacional de San Juan. Facultad de IngenierĂ­a. Instituto de BiotecnologĂ­a; ArgentinaFil: Pantano, MarĂ­a Nadia. Universidad Nacional de San Juan. Facultad de IngenierĂ­a. Instituto de BiotecnologĂ­a; ArgentinaFil: Pedrozo, Lina Paula. Universidad Nacional de San Juan. Facultad de IngenierĂ­a. Instituto de BiotecnologĂ­a; Argentina. Universidad Nacional de San Juan. Facultad de IngenierĂ­a. Instituto de BiotecnologĂ­a; ArgentinaFil: Vazquez, Fabio. Universidad Nacional de San Juan. Facultad de IngenierĂ­a. Instituto de BiotecnologĂ­a; ArgentinaFil: Scaglia, Gustavo Juan Eduardo. Universidad Nacional de San Juan. Facultad de IngenierĂ­a. Instituto de BiotecnologĂ­a; Argentina. Universidad Nacional de San Juan. Facultad de IngenierĂ­a. Instituto de IngenierĂ­a QuĂ­mica; Argentin

    Glycemic Variability Assessed by Continuous Glucose Monitoring and Short-Term Outcome in Diabetic Patients Undergoing Percutaneous Coronary Intervention: An Observational Pilot Study

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    Poor glycemic control is associated with unfavorable outcome in patients undergoing percutaneous coronary intervention (PCI), irrespective of diabetes mellitus. However a complete assessment of glycemic status may not be fully described by glycated hemoglobin or fasting blood glucose levels, whereas daily glycemic fluctuations may influence cardiovascular risk and have even more deleterious effects than sustained hyperglycemia. Thus, this paper investigated the effectiveness of a continuous glucose monitoring (CGM), registering the mean level of glycemic values but also the extent of glucose excursions during coronary revascularization, in detecting periprocedural outcome such as renal or myocardial damage, assessed by serum creatinine, neutrophil gelatinase-associated lipocalin (NGAL), and troponin I levels. High glycemic variability (GV) has been associated with worse postprocedural creatinine and NGAL variations. Moreover, GV, and predominantly hypoglycemic variations, has been observed to increase in patients with periprocedural myocardial infarction. Thus, our study investigated the usefulness of CGM in the setting of PCI where an optimal glycemic control should be achieved in order to prevent complications and improve outcome
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