440 research outputs found

    Study of the deactivation of a commercial catalyst for ethylbenzene dehydrogenation to styrene

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    The catalytic performance and characteristics of an industrial catalyst, fresh and spent, i.e. downloaded from an industrial reactor after a normal lifetime cycle, were compared. Some different causes of catalyst deactivation, such as loss or redistribution of promoters, active phase modification, Fe 3+ reduction, coke deposition on catalyst surface and physical modifications, were evidenced by means of several techniques. All the mentioned causes of deactivation showed strictly interconnected and concurred to the decrease of conversion. However, the key factors leading to irreversible deactivation showed potassium migration towards the inner part of the extrudate particle, its agglomeration into concentrated spots and its volatilisation from the surface, together with the progressive Fe3+ reduction to Fe 2+. These modifications led to the enhancement of coking activity and to the loss of mechanical properties, so making deactivation irreversible

    Autologous US-guided PRP injection versus US-guided focal extracorporeal shock wave therapy for chronic lateral epicondylitis: A minimum of 2-year follow-up retrospective comparative study.

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    PURPOSE: To compare the efficacy of two independent groups of patients treated with ultrasound (US)-guided extracorporeal shock wave (ESW) therapy and with US-guided injection of platelet-rich plasma (PRP) for chronic lateral epicondylitis (LE) with a minimum of 2-year follow-up. METHODS: We retrospectively evaluated 63 patients treated for chronic LE (31 patients with autologous US-guided PRP injection and 32 patients with US-guided focal ESW therapy) from 2009 to 2014. All the patients were evaluated by means of Roles-Maudsley (RM) score, quick Disabilities of Arm, Shoulder, and Hand (QuickDASH) score, visual analogic scale (VAS) and patient-rated tennis elbow evaluation (PRTEE) to retrospectively assess the pain relief, level of activity, the self-reported function and subjective satisfaction at minimum of 2-year follow-up. RESULTS: Both US-guided autologous PRP injection and US-guided focal ESW administration proved effective in chronic LE with significant improvement in the QuickDASH, VAS, RM and PRTEE scores ( p < 0.0001). No adverse effects or complications were recorded in any groups. No differences were found in recurrence rate and final results of the QuickDASH, VAS, RM and PRTEE scores between the two groups ( p > 0.05). The mean time between treatment and symptom resolution was significantly shorter for the PRP treatment ( p = 0.0212); furthermore, the mean time to return to the normal activities was quicker for PRP group ( p = 0.0119). CONCLUSION: Both PRP injection and ESW therapy are feasible and safe options for the treatment of chronic LE with low risk of complications and with good long-term follow-up results. US-guided PRP injection has quick efficacy when compared with US-guided focal ESW therapy

    Producción sin catalizador de ésteres etílicos de ácidos grasos (FAEE) a partir de aceite de pulpa de macauba

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    In this study, the production of fatty acid ethyl esters (FAEE) from macauba pulp oil and pressurized ethanol was investigated. The experiments were conducted without the addition of catalyst, at 20 MPa, to determine the effect of temperature (200 to 300 °C) and the oil to ethanol mass ratio (1:1 and 1:2) on the FAEE content and different residence times (10 to 45 min). The effect of the addition of n-hexane to the oil (20 wt%) as a co-solvent was also evaluated. The use of high temperatures (275 and 300 °C) resulted in high FAEE content (∼90%). Increasing the amount of ethanol in the reaction medium contributed to the formation of esters only at operating temperatures of 200 to 250 °C. It was also observed that with the addition of co-solvent (in the oil) it was possible to obtain high amounts of FAEE in a shorter reaction time. In addition, a low content of unreacted compounds (∼8.0%) and the conversion of ∼90 and 99% of the free fatty acids and triglycerides were observed, respectively.En este estudio, se investigó la producción de ésteres etílicos de ácidos grasos (FAEE) a partir de aceite de pulpa de macauba y etanol presurizado. Los experimentos se realizaron, sin la adición de catalizador, a 20 MPa, para determinar el efecto de la temperatura (200 a 300 °C) y la relación de masa de aceite a etanol (1:1 y 1:2) en el contenido de FAEE, aplicando diferentes tiempos de residencia (10 a 45 min). También se evaluó el efecto de la adición de n-hexano al aceite (20% en peso) como co-disolvente. El uso de altas temperaturas (275 y 300 °C) dio como resultado un alto contenido de FAEE (∼90%). El aumento de la cantidad de etanol en el medio de reacción contribuyó a la formación de ésteres solo a temperaturas de funcionamiento de 200 a 250 °C. También se observó que con la adición de co-disolvente (en el aceite) era posible obtener altas cantidades de FAEE en un tiempo de reacción más corto. Además, se observó un bajo contenido de compuestos sin reaccionar (∼8,0%) y la conversión de ∼90 y 99% de ácidos grasos libres y triglicéridos, respectivamente

    Use of adipose derived stem cells in Treacher Collins syndrome

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    Objective: Treacher Collins syndrome (TCS) is a rare congenital disorder of craniofacial development. TCS occurs with an incidence of 1:50,000, and more than 60% of TCS cases have no previous family history and arise as the result of de novo mutations. The high rate of de novo mutations, together with the extreme variability in the degree to which individuals can be affected, makes the provision of genetic counseling extremely complicated. Consequently, every case of TCS is unique and needs to be assessed individually. Patients with TCS frequently undergo multiple reconstructive surgeries from birth through adulthood, which rarely are fully corrective in the long-term. The nascent field of regenerative medicine offers the promise to improve some of these treatments. In particular, structural fat grafting (SFG) seems to be a good strategy not only to restore the normal volume and contour of the face, but also to provide a source of adipose-derived stem cells (ADSCs) with a multilineage differentiation potential. In this work, we present genetical analyses of ADSC affected by TCS. Materials and methods: ADSCs from were analyzed for their stemness properties and shared many characteristics with those of a healthy subject. Screening of the genome of the TCS patient using array-Comparative Genomic Hybridization allowed us to identify some chromosomal imbalances that are probably associated with TCS. Results: We found that some alterations, involving the TIMELESS gene, were usually associated with embryonic stem cells. Conclusions: With the aim to improve the final results, we need to consider combining knowledge of genetic alterations and expression profiles as a fundamental step before starting with surgical procedures

    Neural processing of emotions in traumatized children treated with eye movement desensitization and reprocessing therapy: a hdEEG study

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    Eye Movement Desensitization and Reprocessing (EMDR) therapy has been proven efficacious in restoring affective regulation in Post-Traumatic Stress Disorder (PTSD) patients. However, its effectiveness on emotion processing in children with complex trauma has yet to be explored. High density Electroencephalography (hdEEG) was used to investigate the effects of EMDR on brain responses to adults\u27 emotions on children with histories of early maltreatment. Ten school-aged children were examined before (T0) and within one month after the conclusion of EMDR (T1). hdEEGs were recorded while children passively viewed angry, afraid, happy, and neutral faces. Clinical scales were administered at the same time. Correlation analyses were performed to detect brain regions whose activity was linked to children\u27s traumatic symptom-related and emotional-adaptive problem scores. In all four conditions, hdEEG showed similar significantly higher activity on the right medial prefrontal and fronto-temporal limbic regions at T0, shifting towards the left medial and superior temporal regions at T1. Moreover, significant correlations were found between clinical scales and the same regions whose activity significantly differed between pre- and post-treatment. These preliminary results demonstrate that, after EMDR, children suffering from complex trauma show increased activity in areas implicated in high-order cognitive processing when passively viewing pictures of emotional expressions. These changes are associated with the decrease of depressive and traumatic symptoms, and with the improvement of emotional-adaptive functioning over time

    Paraoxonase-1 (PON-1) Arylesterase Activity Levels in Patients with Coronary Artery Disease: A Meta-Analysis

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    Aim: To review and compare the PON-1 arylesterase activity between coronary artery disease (CAD) and non-CAD patients. Methods: Data were obtained by searching MEDLINE and Scopus for all investigations published between January 1, 2000 and March 1, 2021 comparing PON-1 arylesterase activity between CAD and controls. Results: Twenty studies, based on 5417 patients, met the inclusion criteria and were included in the analysis. A random effect model revealed that PON-1 arylesterase activity was significantly lower in the CAD group compared to controls (SMD = -0.587, 95%CI = -0.776 to -0.339, p < 0.0001, I2 = 92.3%). In CAD patients, the PON-1 arylesterase activity was significantly higher among CAD patients without diabetes mellitus (DM) compared to those with diabetes (SMD: 0.235, 95% CI: 0.014 to 0.456, p = 0.03, I2 = 0%). Conclusions: PON-1 activity is significantly lower in CAD patients, and those without DM presented a significantly higher PON-1 arylesterase activity

    Multiplex Matrix Metalloproteinases Analysis in the Cerebrospinal Fluid Reveals Potential Specific Patterns in Multiple Sclerosis Patients.

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    Background: Matrix metalloproteinases (MMPs) are pleiotropic enzymes involved in extracellular protein degradation and turnover. MMPs are implicated in the pathogenesis of many neurological diseases, including multiple sclerosis (MS). Objective: To search the level of MMPs in the cerebrospinal fluid (CSF) of MS patients and detect possible disease-specific patterns. Methods: CSF samples from 32 MS patients and, from 15 control subjects with other inflammatory neurological diseases (OIND) were analyzed. The Bio-Plex Pro Human MMP 9-Plex Panel (Bio-Rad) was used for the quantification of MMP-1, MMP-2, MMP-3, MMP-7, MMP-8, MMP-9, MMP-10, MMP-12, and MMP-13. Results: CSF MMP-1 and MMP-12 levels were significantly reduced in MS as compared with OIND. In MS patients' CSF: (i) MMP-1 levels were significantly higher in women vs. men; (ii) MMP-10 concentrations were higher in patients with CSF-restricted IgG oligoclonal bands, and (iii) MMP-7 levels were increased in patients with longer disease duration. In the OIND group MMP-7 and MMP-12 levels significantly and directly correlated with age. Conclusions: Our study contributes to investigating the role of MMPs in MS, with regard to CSF immunological features and disease duration. Sex-specific differences were also detected in MMPs CSF levels
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