2,267 research outputs found

    Study of the influence of Xanthate Derivative Structures on Copper Sulfide Mineral Adsorption Under Acidic Conditions

    Get PDF
    Artículo de investigación en revista indizadaAdsorption of commercial xanthate derivatives on copper sulfide mineral (covellite, CuS) was studied by kinetics and isotherm adsorption experiments. The adsorption of xanthate derivatives was confirmed by FTIR (Fourier transform infrared spectroscopy) and XPS (X-ray photoelectron spectroscopy) results. Experiments were performed with two different xanthate derivatives, C-4410 (O-pentyl S-2-propenyl ester) and C-4940 (isobutyl xanthogen ethyl formate), on individual doses of 0.05 g of powdered covellite. It was found that the equilibrium times at pH 2, 4, and 6 were different for both xanthate derivatives. The shortest times were achieved at pH 2 and 4. The results suggest that C-4110 can be used as collector in a wide range of pH, while C-4940 is limited to lower pH values. Pseudo first- and pseudo second-order kinetics models were thus applied to the experimental data for pH 2. The information obtained from the kinetics models combined with XPS allowed proposing the adsorption mechanism for the covellite-xanthate derivative pair. The adsorption takes place through a non-covalent interaction for C-4410 and chemisorption process for C-4940. The best-fitting isotherm models for C-4410 and C-4940 adsorption were Redlich–Peterson and Freundlich, respectively, which yield a maximum adsorption capacity of 57.07 mg g 1 for C-4410 and 44.62 mg g 1 for C-4940.CONACYT CB-254952-201

    Paraneoplastic Cerebellar Degeneration Secondary to BRAF Mutant Melanoma Metastasis from an Occult Primary Cancer

    Get PDF
    Melanoma metastasis from an unknown primary cancer has an incidence of 3.2% among melanoma patients. Furthermore, paraneoplastic neurological syndromes (PNS) are rare, occurring in 1-3% of patients with malignancies. Paraneoplastic cerebellar degeneration (PCD) is one of the classic PNS and is characterized by acute or subacute onset of ataxia and/or presence of onconeural antibodies. A 61-year-old male with ataxia, vertigo, and headache later developed dysarthria, multidirectional nystagmus, hyperactive delirium, auditory hallucinations, psychomotor agitation, and myoclonus. Toxicological, metabolic, infectious, and autoimmune etiologies were assessed and reported negative. An osteolytic lesion was observed in the right iliac crest via computed tomography (CT). A positron emission tomography-CT reported increased fluorodeoxyglucose uptake of a right iliac and right inguinal ganglion. After biopsy of the right inguinal ganglion, a BRAF mutation-positive melanoma metastasis from an occult primary cancer was diagnosed. Dermatologic, ophthalmologic, and endoscopic gastrointestinal assessment did not reveal a primary malignant melanoma. The patient's movement disorders and neuropsychiatric symptoms improved with quetiapine, prednisone, azathioprine, and cyclophosphamide. Oncological management was conducted with MAPK pathway inhibitors (i.e., dabrafenib and trametinib). Movement disorders associated with neuropsychiatric symptoms are complex to diagnose. PNS are rare and often associated with antibodies against neural antigens expressed by the tumor. The case presented above describes a patient with a BRAF-positive malignant melanoma metastasis from an occult primary associated with PCD - to the best of our knowledge, the first reported in the literature.</p

    High-Resolution Distributed Differential Curvature Measurement Based on Phase-Sensitive Optical Time Domain Reflectometry and Multi-Core Fiber

    Get PDF
    A distributed curvature sensor based on multicore fiber and phase-sensitive optical time domain reflectometry is presented, demonstrating a resolution of 10 cm over ~25 m of sensing range

    Risk Factors and Predictive Score for Bacteremic Biliary Tract Infections Due to Enterococcus faecalis and Enterococcus faecium: a Multicenter Cohort Study from the PROBAC Project

    Get PDF
    Biliary-tract bloodstream infections (BT-BSI) caused by Enterococcus faecalis and E. faecium are associated with inappropriate empirical treatment and worse outcomes compared to other etiologies. The objective of this study was to investigate the risk factors for enterococcal BT-BSI. Patients with BT-BSI from the PROBAC cohort, including consecutive patients with BSI in 26 Spanish hospitals between October 2016 and March 2017, were selected; episodes caused by E. faecalis or E. faecium and other causes were compared. Independent predictors for enterococci were identified by logistic regression, and a predictive score was developed. Eight hundred fifty episodes of BT-BSI were included; 73 (8.5%) were due to target Enterococcus spp. (48 [66%] were E. faecium and 25 [34%] E. faecalis). By multivariate analysis, the variables independently associated with Enterococcus spp. were (OR; 95% confidence interval): cholangiocarcinoma (4.48;1.32 to 15.25), hospital acquisition (3.58;2.11 to 6.07), use of carbapenems in the previous month (3.35;1.45 to 7.78), biliary prosthesis (2.19;1.24 to 3.90), and moderate or severe chronic kidney disease (1.55;1.07 to 2.26). The AUC of the model was 0.74 [95% CI0.67 to 0.80]. A score was developed, with 7, 6, 5, 4, and 2 points for these variables, respectively, with a negative predictive value of 95% for a score ? 6. A model, including cholangiocarcinoma, biliary prosthesis, hospital acquisition, previous carbapenems, and chronic kidney disease showed moderate prediction ability for enterococcal BT-BSI. Although the score will need to be validated, this information may be useful for deciding empirical therapy in biliary tract infections when bacteremia is suspected. IMPORTANCE Biliary tract infections are frequent, and a significant cause of morbidity and mortality. Bacteremia is common in these infections, particularly in the elderly and patients with cancer. Inappropriate empirical treatment has been associated with increased risk of mortality in bacteremic cholangitis, and the probability of receiving inactive empirical treatment is higher in episodes caused by enterococci. This is because many of the antimicrobial agents recommended in guidelines for biliary tract infections lack activity against these organisms. To the best of our knowledge, this is the first study analyzing the predictive factors for enterococcal BT-BSI and deriving a predictive score

    Risk Factors and Predictive Score for Bacteremic Biliary Tract Infections Due to Enterococcus faecalis and Enterococcus faecium: a Multicenter Cohort Study from the PROBAC Project

    Get PDF
    Biliary-tract bloodstream infections (BT-BSI) caused by Enterococcus faecalis and E. faecium are associated with inappropriate empirical treatment and worse outcomes compared to other etiologies. The objective of this study was to investigate the risk factors for enterococcal BT-BSI. Patients with BT-BSI from the PROBAC cohort, including consecutive patients with BSI in 26 Spanish hospitals between October 2016 and March 2017, were selected; episodes caused by E. faecalis or E. faecium and other causes were compared. Independent predictors for enterococci were identified by logistic regression, and a predictive score was developed. Eight hundred fifty episodes of BT-BSI were included; 73 (8.5%) were due to target Enterococcus spp. (48 [66%] were E. faecium and 25 [34%] E. faecalis). By multivariate analysis, the variables independently associated with Enterococcus spp. were (OR; 95% confidence interval): cholangiocarcinoma (4.48;1.32 to 15.25), hospital acquisition (3.58;2.11 to 6.07), use of carbapenems in the previous month (3.35;1.45 to 7.78), biliary prosthesis (2.19;1.24 to 3.90), and moderate or severe chronic kidney disease (1.55;1.07 to 2.26). The AUC of the model was 0.74 [95% CI0.67 to 0.80]. A score was developed, with 7, 6, 5, 4, and 2 points for these variables, respectively, with a negative predictive value of 95% for a score # 6. A model, including cholangiocarcinoma, biliary prosthesis, hospital acquisition, previous carbapenems, and chronic kidney disease showed moderate prediction ability for enterococcal BT-BSI. Although the score will need to be validated, this information may be useful for deciding empirical therapy in biliary tract infections when bacteremia is suspected. IMPORTANCE Biliary tract infections are frequent, and a significant cause of morbidity and mortality. Bacteremia is common in these infections, particularly in the elderly and patients with cancer. Inappropriate empirical treatment has been associated with increased risk of mortality in bacteremic cholangitis, and the probability of receiving inactive empirical treatment is higher in episodes caused by enterococci. This is because many of the antimicrobial agents recommended in guidelines for biliary tract infections lack activity against these organisms. To the best of our knowledge, this is the first study analyzing the predictive factors for enterococcal BT-BSI and deriving a predictive score.8 página

    XXV Curso Monográfico de Psiquiatría Infantil y la Adolescencia: Tópicos de Psicofarmacología Infantil - 2023

    Get PDF
    El XXV Curso Monográfico de Psiquiatría Infantil y de la Adolescencia, titulado "Tópicos de Psicofarmacología Infantil," fue un evento destacado en el campo de la salud mental infantil y adolescente. Durante tres días en septiembre de 2023, expertos líderes en la materia se reunieron para explorar a fondo la psicofarmacología en este grupo de edad. El evento, dedicado a la memoria del Dr. Francisco Javier Valencia Granados, comenzó con una ceremonia de inauguración en la que participaron autoridades institucionales. Luego, se sucedieron conferencias magistrales que abordaron una amplia variedad de temas cruciales. Estos incluyeron aspectos fundamentales como la neurobioquímica farmacológica y una introducción a la psicofarmacología. El programa se adentró en cuestiones específicas, como el uso de antipsicóticos en paidopsiquiatría, el abordaje de trastornos del aprendizaje, el tratamiento del suicidio desde una perspectiva psicofarmacológica, y la gestión farmacológica del insomnio en niños. Se exploraron temas especializados, como el tratamiento de la esquizofrenia en pacientes infantiles. El segundo día se centró en trastornos emocionales en niños y adolescentes, destacando el tratamiento del trastorno depresivo, los trastornos ansiosos y el espectro autista. Se presentaron enfoques vanguardistas, como el uso de psicodélicos en adolescentes y las novedades en psicofarmacología, como el dextrometorfano y el bupropión. También se discutió el manejo de la epilepsia y la adicción a los videojuegos. El tercer día se enfocó en el tratamiento farmacológico de trastornos pediátricos específicos, como el trastorno bipolar, el déficit de atención e hiperactividad, la enuresis y encopresis, parasomnias, y el abordaje neuropsiquiátrico en pacientes pediátricos con VIH. Se exploraron también trastornos de la conducta alimentaria y la disforia de género. El evento culminó con una reflexión sobre la salud mental en niños y un emotivo tributo al Dr. Francisco Javier
    corecore