The Impact of United States Medical Licensing Examination Step 1 Transitioning To Pass/Fail on Medical Student Perception of Research Needed to Match Into One's Preferred Specialty.

Purpose To evaluate how the transition of United States Medical Licensing Examination (USMLE) Step 1 to a pass/fail scoring influenced medical student perceptions of the importance of research required to match into their preferred residency specialty. Methods A 14-item survey was distributed by e-mail to medical students at one medical school in the southeastern United States in November of 2021. Responses were compared between medical students taking USMLE Step 1 pass/fail in the future and medical students taking USMLE Step 1 for a three-digit score. Results A total of 168 medical students responded to the survey with 98 respondents who planned on taking USMLE Step 1 pass/fail (45 first-year medical students (MS1) and 53 MS2) and 70 respondents who took USMLE Step 1 for a numerical score (37 MS3 and 33 MS4). There were no differences in how each cohort scored the level of importance of research in matching into their preferred residency specialty (p=0.10); however, those taking USMLE Step 1 pass/fail believe an average of 4.6 research experiences are necessary to match into their preferred residency, compared to only 3.4 research experiences for those who took it for a numerical score (p=0.04). Conclusion No statistically significant difference in the perceived importance of research in matching into one's preferred residency specialty was found between cohorts. However, the pass/fail cohort believes they will need more research experiences to match their chosen specialty than the numerical score cohort. Results could indicate that students participate in more research and extracurricular activities to be more competitive for residency applications.

[Concordance of medication prescription records in the hospitalised surgical patient]. / Concordancia de los registros de prescripción de medicamentos en el paciente quirúrgico hospitalizado.

INTRODUCTION: Electronic prescription is the prescription system that allows healthcare professionals to send medication prescriptions directly to community pharmacies and the outpatient unit of Hospital Pharmacy Services for dispensing. However, there is difficulty in obtaining a reliable pharmacotherapeutic history in chronic patients through electronic prescription upon hospital admission as a critical point for adequate treatment adaptation. Therefore, the pharmacist as a member of the multidisciplinary team must ensure, through medication conciliation, an adequate transition of care through the correct management of the treatment that the chronic patient requires during their hospitalization. OBJECTIVES: To evaluate the quality of electronic prescription records for routine chronic treatment by analyzing the concordance of the electronic prescription. MATERIAL AND METHODS: Observational, cross-sectional and retrospective study at the General University Hospital of Elche. Hospitalized patients in charge of the Orthopedic Surgery and Traumatology, Urology and Neurosurgery Services in which the responsible doctor requested medication reconciliation by the Pharmacy Service between January 2022 - December 2022 were included. RESULTS: 378 patients, 209 (55.3%) women and 169 (44.7%) men, with a mean age±standard deviation of 71.0±11.6 years and 69.0±11.8 years, respectively. The total percentage of patients with discrepancies in the electronic prescription with respect to the usual chronic treatment was 60.6%, reflecting that only 39.4% of the patients had non-discordant electronic prescriptions. CONCLUSIONS: More than half of hospitalized surgical patients present discrepancies in the medications prescribed in the home electronic prescription, which justifies the importance of treatment reconciliation upon admission carried out by hospital pharmacists.

Epidemiology of fungal infection in COVID 19 in Spain during 2020 and 2021: a nationwide study.

We realize a nationwide population-based retrospective study to analyze the characteristics and risk factors of fungal co-infections in COVID-19 hospitalized patients as well as describe their causative agents in the Spanish population in 2020 and 2021. Data were obtained from records in the Minimum Basic Data Set of the National Surveillance System for Hospital Data in Spain, provided by the Ministry of Health, and annually published with two years lag. The assessment of the risk associated with the development of healthcare-associated fungal co-infections was assessed using an adjusted logistic regression model. The incidence of fungal co-infection in COVID-19 hospitalized patients was 1.41%. The main risk factors associated were surgery, sepsis, age, male gender, obesity, and COPD. Co-infection was associated with worse outcomes including higher in-hospital and in ICU mortality, and higher length of stay. Candida spp. and Aspergillus spp. were the microorganisms more frequent. This is the first study analyzing fungal coinfection at a national level in hospitalized patients with COVID-19 in Spanish population and one of the few studies available that demonstrate that surgery was an independent risk factor of Aspergillosis coinfection in COVID-19 patients.

Spinal gunshot wounds: A retrospective, multicenter, cohort study. / [Artículo traducido] Lesiones vertebrales por proyectil de arma de fuego: estudio de cohorte retrospectivo, multicéntrico.

INTRODUCTION AND OBJECTIVE: To describe the demographic and clinical characteristics and treatment of patients with spinal gunshot wounds across Latin America. MATERIAL AND METHODS: Retrospective, multicenter cohort study of patients treated for gunshot wounds to the spine spanning 12 institutions across Latin America between January 2015 and January 2022. Demographic and clinical data were recorded, including the time of injury, initial assessment, characteristics of the vertebral gunshot injury, and treatment. RESULTS: Data on 423 patients with spinal gunshot injuries were extracted from institutions in Mexico (82%), Argentina, Brazil, Colombia, and Venezuela. Patients were predominantly male civilians in low-risk-of-violence professions, and of lower/middle social status, and a sizeable majority of gunshots were from low-energy firearms. Vertebral injuries mainly affected the thoracic and lumbar spine. Neurological injury was documented in 320 (76%) patients, with spinal cord injuries in 269 (63%). Treatment was largely conservative, with just 90 (21%) patients treated surgically, principally using posterior open midline approach to the spine (79; 87%). Injury features distinguishing surgical from non-surgical cases were neurological compromise (P = 0.004), canal compromise (P < 0.001), dirty wounds (P < 0.001), bullet or bone fragment remains in the spinal canal (P < 0.001) and injury pattern (P < 0.001). After a multivariate analysis through a binary logistic regression model, the aforementioned variables remained statistically significant except neurological compromise. CONCLUSIONS: In this multicenter study of spinal gunshot victims, most were treated non-surgically, despite neurological injury in 76% and spinal injury in 63% of patients.

Brent Technique of Repair Versus Nagata Auricular Reconstruction for Microtia Reconstruction: A Systematic Review and Meta-Analysis.

BACKGROUND: Up to 17.4 in every 10,000 births are affected by microtia, but no consensus exists on a gold standard technique for autogenous repair. In this study, the authors compare 2 common methods-the Brent and Nagata autogenous costal cartilage ear reconstruction techniques. A systematic review of the literature and a quantitative meta-analysis to compare the outcomes of these 2 approaches were performed. The outcomes analyzed included rates of infection, necrosis, cartilage exposure, cartilage resorption, hematoma, wire extrusion, and hypertrophic scar. METHODS: A MEDLINE database systematic review with the following keywords: microtia, Brent, and Nagata was performed. Case reports and articles without original data or patient outcomes were excluded. Inclusion methods for study selection are outlined in Supplemental Digital Content 1, http://links.lww.com/SCS/F461 , below. The prevalence of outcomes for each study was analyzed through meta-analysis of proportions using Stata. RESULTS: A total of 536 potential studies were retrieved for review. Twelve of these studies met inclusion criteria. Four studies utilized the Brent method of repair with the inclusion of 563 ear reconstructions. Nine studies implemented the Nagata technique in 2304 reconstructions. Two studies directly compared the Brent (327 ears) and Nagata (471 ears) techniques. The calculated rate and 95% confidence intervals are summarized in Supplemental Digital Content 2, http://links.lww.com/SCS/F461 . There were no statistically significant differences in complication rates between the Brent and Nagata microtic reconstruction techniques identified in this study. CONCLUSIONS: The Brent and Nagata microtia reconstruction techniques have no difference in the risk of infection, necrosis, cartilage exposure, cartilage resorption, hematoma, wire extrusion, or hypertrophic scars.

A systematic review and meta-analysis on the influence of sociodemographic factors on amputation in patients with peripheral arterial disease.

OBJECTIVE: To identify disparities in sociodemographic factors that are associated with major lower limb amputation in patients with peripheral arterial disease (PAD). METHODS: A systematic review of the literature was performed to identify studies that reported major lower limb amputation rates in patients with PAD among different sociodemographic groups. Data that compared amputation rates on the basis of sex, race, ethnicity, income, insurance, geography, and hospital type were collected and described. Outcomes were then aggregated and standardized, and a meta-analysis was performed to synthesis data into single odds ratios (ORs). RESULTS: Forty-one studies were included in the review. There was no association found between males and females (OR, 0.95; 95% confidence interval [CI], 0.90-1.00). Compared with Whites, higher rates of amputation were seen among Blacks/African Americans (OR, 2.02; 95% CI, 1.81-2.26) and Native Americans (OR, 1.22; 95% CI, 1.04-1.45). No significant association was found between Whites and Asians, Native Hawaiians, or Pacific Islanders (OR, 1.15; 95% CI, 1.00-1.33). Hispanics had higher rates of amputation compared with non-Hispanics (OR, 1.36; 95% CI, 1.22-1.52). Compared with private insurance, higher rates of amputation were seen among Medicare patients (OR, 1.38; 95% CI, 1.27-1.50), Medicaid patients (OR, 1.59; 95% CI, 1.44-1.76), and noninsured patients (OR, 1.41; 95% CI, 1.02-1.95). Compared with the richest income quartile, higher rates of amputation were seen among the second income quartile (OR, 1.10; 95% CI, 1.05-1.15), third income quartile (OR, 1.20; 95% CI, 1.07-1.35), and bottom income quartile (OR, 1.36; 95% CI, 1.24-1.49). There was no association found between rural and urban populations (OR, 1.35; 95% CI, 0.92-1.97) or between teaching and nonteaching hospitals (OR, 1.01; 95% CI, 0.91-1.12). CONCLUSIONS: Our study has identified a number of disparities and quantified the influence of sociodemographic factors on major lower limb amputation rates owing to PAD between groups. We believe these findings can be used to better target interventions aimed at decreasing amputation rates, although further research is needed to better understand the mechanisms behind our findings.

Discovery of Gamma Rays from the Quiescent Sun with HAWC.

We report the first detection of a TeV γ-ray flux from the solar disk (6.3σ), based on 6.1 years of data from the High Altitude Water Cherenkov (HAWC) observatory. The 0.5-2.6 TeV spectrum is well fit by a power law, dN/dE=A(E/1 TeV)^{-γ}, with A=(1.6±0.3)×10^{-12} TeV^{-1} cm^{-2} s^{-1} and γ=3.62±0.14. The flux shows a strong indication of anticorrelation with solar activity. These results extend the bright, hard GeV emission from the disk observed with Fermi-LAT, seemingly due to hadronic Galactic cosmic rays showering on nuclei in the solar atmosphere. However, current theoretical models are unable to explain the details of how solar magnetic fields shape these interactions. HAWC's TeV detection thus deepens the mysteries of the solar-disk emission.

Autologous Fat Versus Hydroxyapatite Cement for Use in Frontal Sinus Obliteration: Systematic Review and Meta-Analysis.

BACKGROUND: Frontal sinus obliteration is a possible terminus for the management of chronic sinusitis, frontal bone trauma, cancer extirpation, or mucocele. The mucosa of the sinus is stripped and space obliterated with either autogenic, allopathic, or synthetic materials. This study aimed to compare the outcomes of autologous fat and hydroxyapatite cement (HAC) for frontal sinus obliteration. METHODS: A multidatabase systematic review was conducted to collect outcomes on frontal sinus obliterations with either autologous fat or HAC. Outcomes collected included infection of the frontal sinus or obliteration material, mucocele formation, skin infection at the operative site, hematoma or seroma, cosmetic defect, donor site infection, and need for revision procedure. Prevalence of outcomes was analyzed through meta-analysis of proportions. RESULTS: Twenty studies were ultimately included in the meta-analysis. Sixteen studies reported outcomes for 667 patients obliterated with autologous fat, and 7 studies reported outcomes for 100 patients obliterated with HAC. Prevalence of infection of the frontal sinus or obliteration material, mucocele formation, skin infection at the operative site, hematoma or seroma, and cosmetic defect did not differ statistically between the cohorts. Donor site infection secondary to fat harvesting for fat obliteration had a prevalence of <0.01. Revision rate was 0.04 (95% confidence interval, 0.01-0.8) for fat obliteration and 0.10 (95% confidence interval, 0.00-0.33) for HAC obliteration. CONCLUSIONS: No statistically significant differences in the studied outcomes were detected between obliterations with autologous fat and HAC, suggesting that either is equally suitable and may be up to the surgeon's preference.

Epidemiología de la COVID-19 entre el personal de centros sanitarios y sociosanitarios del área sanitaria de A Coruña y Cee / COVID-19 epidemiology in health and social health workers in the health area of A Coruña and Cee

Objetivo Desde el comienzo de la pandemia ha sido necesario conocer la evolución epidemiológica del SARS-CoV-2. Es por ello que el objetivo de este estudio fue describir las características de la casuística de la COVID-19 en el personal de centros sanitarios y sociosanitarios del área sanitaria de A Coruña y Cee durante la primera ola epidémica, así como determinar la asociación entre el cuadro clínico y/o la duración del mismo y la condición de repositivizar la RT-PCR. Material y métodos En el periodo de estudio se diagnosticaron 210 casos de COVID-19 entre el personal sanitario y sociosanitario del área sanitaria de A Coruña y Cee. Se llevó a cabo un análisis descriptivo de los factores sociodemográficos, así como la búsqueda de asociación entre el cuadro clínico y la duración de la detección de una RT-PCR positiva. Resultados Las categorías profesionales más afectadas fueron enfermería (33,3%) y auxiliares de enfermería (16,2%). El tiempo medio que los casos tardaron en negativizar la RT-PCR fue de 18,3±9,1 días, con una mediana de 17 días. Se observó que 26 casos (13,8%) volvían a obtener un resultado positivo en alguna RT-PCR posterior, sin cumplir criterios de reinfección. La existencia de manifestaciones cutáneas y artralgias se asoció con la repositivización tras ajustar por edad y sexo (OR=4,6 y OR=6,5; respectivamente). Conclusiones En los profesionales sanitarios diagnosticados con COVID-19 durante la primera ola, los síntomas disnea, manifestaciones cutáneas y artralgias determinaron la repositivización de la RT-PCR tras un resultado negativo previo y sin cumplir criterios de reinfección (AU)

Objective Since the beginning of the pandemic, it has become necessary to know the epidemiological evolution of SARS-CoV-2. Therefore, this study aims to describe the characteristics of the casuistry of COVID-19 in health and social-health workers in the health area of A Coruña and Cee during the first epidemic wave, as well as to determine the association between the clinical profile and/or its duration and the condition of RT-PCR repositivization. Materials and methods During the study period, 210 cases belonging to healthcare and social-healthcare workers from the healthcare area of A Coruña and Cee were diagnosed. A descriptive analysis of sociodemographic factors was carried out, as well as the search for association between the clinical picture and the duration of detection of a positive RT-PCR. Results The most affected categories were nursing (33.3%) and nursing assistants (16.2%). The mean time taken for cases to become RT-PCR negative was 18.3±9.1 days, with a median of 17. It was observed that 26 cases (13.8%) had a positive result in a subsequent RT-PCR, without meeting criteria for reinfection. The existence of skin manifestations and arthralgias was associated with repositivization after adjusting for age and sex (OR=4.6 and OR=6.5, respectively). Conclusions In healthcare professionals diagnosed with COVID-19 during the first wave, symptoms such as dyspnea, skin manifestations and arthralgias led to RT-PCR repositivization after a previous negative result and without meeting criteria for reinfection (AU)

Spinal gunshot wounds: A retrospective, multicenter, cohort study.

INTRODUCTION AND OBJECTIVE: To describe the demographic and clinical characteristics and treatment of patients with spinal gunshot wounds across Latin America. MATERIAL AND METHODS: Retrospective, multicenter cohort study of patients treated for gunshot wounds to the spine spanning 12 institutions across Latin America between January 2015 and January 2022. Demographic and clinical data were recorded, including the time of injury, initial assessment, characteristics of the vertebral gunshot injury, and treatment. RESULTS: Data on 423 patients with spinal gunshot injuries were extracted from institutions in Mexico (82%), Argentina, Brazil, Colombia, and Venezuela. Patients were predominantly male civilians in low-risk-of-violence professions, and of lower/middle social status, and a sizeable majority of gunshots were from low-energy firearms. Vertebral injuries mainly affected the thoracic and lumbar spine. Neurological injury was documented in n=320 (76%) patients, with spinal cord injuries in 269 (63%). Treatment was largely conservative, with just 90 (21%) patients treated surgically, principally using posterior open midline approach to the spine (n=79; 87%). Injury features distinguishing surgical from non-surgical cases were neurological compromise (p=0.004), canal compromise (p<0.001), dirty wounds (p<0.001), bullet or bone fragment remains in the spinal canal (p<0.001) and injury pattern (p<0.001). After a multivariate analysis through a binary logistic regression model, the aforementioned variables remained statistically significant except neurological compromise. CONCLUSIONS: In this multicenter study of spinal gunshot victims, most were treated non-surgically, despite neurological injury in 76% and spinal injury in 63% of patients.

Bridging the educational gap in terms of digital competences between healthcare institutions' demands and professionals' needs.

BACKGROUND: Healthcare professionals with insufficient digital competence can be detrimental to patient safety and increase the incidence of errors. In order to guarantee proper care, healthcare organizations should provide opportunities to learn how to use technology, especially for those professionals who have not received training about this topic during their undergraduate studies. OBJECTIVE: This exploratory study aimed to conduct surveys among Spanish healthcare professionals to determine whether their organisations had trained them in the use of healthcare technology and the areas where most emphasis was placed. METHODS: 1624 Spanish healthcare professionals responded to an ad hoc online survey 7 questions related to the digital skill training offered by the healthcare organisations they work for. RESULTS: Nurses were the most widely represented group, making up 58.29% of the total, followed by physicians namely 26.49%. Only 20% of the nurses surveyed had received some training from their institution related to healthcare technology. According to the participants' responses, physicians received significantly more training in this area than nurses. Training related to database searching for research purposes or computer management followed the same trend. Nurses also received less training than physicians in this area. 32% of physicians and nurses paid for their own training if they did not receive any training from institutions. CONCLUSIONS: Nurses receive less training, on topics such as database searching or management, from the healthcare centres and hospitals where they work. Moreover, they also have fewer research and digital skills. Both of these factors may lead to deficits in their care activities, and have adverse effects on patients. Not to mention fewer opportunities for professional progress.

Epidemiology of bacterial co-infections and risk factors in COVID-19-hospitalized patients in Spain: a nationwide study.

BACKGROUND: We performed a nationwide population-based retrospective study to describe the epidemiology of bacterial co-infections in coronavirus disease 2019 (COVID-19)-hospitalized patients in Spain in 2020. We also analyzed the risk factors for co-infection, the etiology and the impact in the outcome. METHODS: Data were obtained from records in the Minimum Basic Data Set (MBDS) of the National Surveillance System for Hospital Data in Spain, provided by the Ministry of Health and annually published with 2 years lag. COVID-19 circulated in two waves in 2020: from its introduction to 31st June and from 1st July to 31st December. The risk of developing a healthcare-associated bacterial co-infection and the risk for in-hospital and intensive care unit (ICU) mortality in co-infected patients was assessed using an adjusted logistic regression model. RESULTS: The incidence of bacterial co-infection in COVID-19 hospitalized patients was 2.3%. The main risk factors associated with bacterial co-infection were organ failure, obesity and male sex. Co-infection was associated with worse outcomes including higher in-hospital, in-ICU mortality and higher length of stay. Gram-negative bacteria caused most infections. Causative agents were similar between waves, although higher co-infections with Pseudomonas spp. were detected in the first wave and with Haemophilus influenzae and Streptococcus pneumoniae in the second. CONCLUSIONS: Co-infections are not as common as those found in other viral respiratory infections; therefore, antibiotics should be used carefully. Screening for actual co-infection to prescribe antibiotic therapy when required should be performed.

[COVID-19 epidemiology in health and social health workers in the health area of A Coruña and Cee]. / Epidemiología de la COVID-19 entre el personal de centros sanitarios y sociosanitarios del área sanitaria de A Coruña y Cee.

OBJECTIVE: Since the beginning of the pandemic, it has become necessary to know the epidemiological evolution of SARS-CoV-2. Therefore, this study aims to describe the characteristics of the casuistry of COVID-19 in health and social-health workers in the health area of A Coruña and Cee during the first epidemic wave, as well as to determine the association between the clinical profile and/or its duration and the condition of RT-PCR repositivization. MATERIALS AND METHODS: During the study period, 210 cases belonging to healthcare and social-healthcare workers from the healthcare area of A Coruña and Cee were diagnosed. A descriptive analysis of sociodemographic factors was carried out, as well as the search for association between the clinical picture and the duration of detection of a positive RT-PCR. RESULTS: The most affected categories were nursing (33.3%) and nursing assistants (16.2%). The mean time taken for cases to become RT-PCR negative was 18.3±9.1 days, with a median of 17. It was observed that 26 cases (13.8%) had a positive result in a subsequent RT-PCR, without meeting criteria for reinfection. The existence of skin manifestations and arthralgias was associated with repositivization after adjusting for age and sex (OR=4.6 and OR=6.5, respectively). CONCLUSIONS: In healthcare professionals diagnosed with COVID-19 during the first wave, symptoms such as dyspnea, skin manifestations and arthralgias led to RT-PCR repositivization after a previous negative result and without meeting criteria for reinfection.

Cognitive Functioning in Adults with Phenylketonuria in a Cohort of Spanish Patients.

The early introduction of a low phenylalanine (Phe) diet has been demonstrated to be the most successful treatment in subjects with phenylketonuria (PKU), especially for preventing severe cognitive and neurological damages. However, it still concerns that even if treated in the first months of life with supplements and following a diet, they can show slight scores below people without PKU in neuropsychological assignments. We investigated 20 adults with classical PKU aged 19-48 years (mean age 29 years) and 20 heathy controls matched by age, gender, and years of education. Patients and controls were assessed with an extended neuropsychological battery, as well as psychological aspects and quality of life, also the last Phe level result was obtained. Results showed that the most affected cognitive domains are processing speed, executive functioning, memory, and also theory of mind, but very well-preserved verbal fluency, language, and visuospatial functioning. In quality of life, some significant results were seen specially in anxiety of Phe levels, anxiety of Phe levels during pregnancy, guilt if poor adherence to supplements, and if dietary protein restriction not followed. No significant results were obtained for the psychological variables. In conclusion, it has been shown that a combination of a low Phe diet, supplement intake, and keeping Phe levels in a low range seems appropriate to have the most normal and alike cognitive performance to persons without PKU.

Embryo Selection for a Carrier of an Early-Onset Alzheimer's Disease-Associated Mutation in the PSEN1 Gene.

Alzheimer's disease (AD) is the most common neurodegenerative dementia. It manifests as early-onset or late-onset AD. Early-onset AD represents about 5.5% of the total cases and occurs in patients under age 65. The EOAD progresses more aggressively and has a shorter life expectancy due to a greater pathogenic load. We present two asymptomatic siblings, a 30-year-old male and a 34- year-old female, who are heterozygous carriers of a pathogenic variant c.428T>C (Ile143Thr) in the presenilin 1 (PSEN1) gene. During genetic counseling, assisted reproduction techniques (ART) coupled with embryo biopsy and a preimplantation genetic test for monogenic disorders (PGT-M) were recommended to provide reproductive care for the patients and their partners. ART and preimplantation genetic testing (PGT) have made it possible to have chromosomally normal and genetically unaffected offspring, allowing patients with genetic diseases to become parents.

Non-convulsive status epilepticus as the initial manifestation in a family with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL).

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an autosomal dominant small-vessel disease caused by mutations of the NOTCH3 gene. It typically presents with migraine, recurrent brain ischaemia, and cognitive disorders. Seizures rarely present as the initial manifestation, with non-convulsive status epilepticus being even less frequent. We present a series of 3 related patients with this arteriopathy, 2 of whom presented status epilepticus as a manifestation of the disease.

Use of X-Ray Photoelectron Spectroscopy as an analytical tool for the study of contamination by Teflon in the synthesis of Mo(VI)Cl2O2Bipy/ TiO2 catalysts

The preparation of catalysts can involve various sources of contamination, which can seriously affect the quality of the prepared materials. In the present work, a case of fluorine contamination in a set of catalyst samples was studied, in which using the X-Ray Photoelectron Spectroscopy (XPS) technique, it was evidenced by the F 1s signal that this element was present in the form of Teflon, since its binding energy corresponded mainly to the CF2 species. Furthermore, using the C 1s signal, it was also possible to corroborate the presence of the CF2 group, which is associated with the main component of the Teflon carbon chains. The use of this information made it possible to identify that the solvent dehydration procedure (previous step to obtaining the catalysts) could lead to contamination with Teflon since it involved various accessories with Teflon, organic solvents and high temperature; the Teflon tape and the magnetic stirrer being the possible sources of contamination.

La preparación de catalizadores puede contener diversas fuentes de contaminación, las cuales pueden afectar seriamente las propiedades de los materiales preparados. En este artículo se estudió un caso de contaminación con flúor en una serie de muestras de catalizadores. Empleando la técnica de espectroscopia fotoelectrónica de rayos X (XPS) se evidenció la presencia de flúor en la superficie de los materiales, el cual estaba asociado al polímero teflón, ya que su energía de enlace correspondía principalmente con la de la especie CF2. Además, empleando la señal C 1s, se logró corroborar la presencia de la especie CF2, el cual está asociado al componente principal de las cadenas carbonadas de teflón. El uso de la información obtenida por XPS permitió determinar que durante la deshidratación del solvente (paso previo para la obtención de los catalizadores en el cual se emplean solventes orgánicos y alta temperatura) se podría estar llevando a cabo la contaminación con teflón, ya que este componente está presente en diversos accesorios empleados en el proceso de deshidratación, siendo la cinta de teflón y el agitador magnético las posibles fuentes de contaminación.

A preparação de catalisadores pode conter diversas fontes de contaminação, as quais podem afeitar seriamente as propriedades dos materiais preparados. No presente trabalho estudou-se um caso de contaminação com flúor numa série de amostras de catalisadores. Usando a técnica da espectroscopia fotoeletrônica de raios X (XPS), evidenciou-se a presença de flúor na superfície dos materiais, o qual estava associado ao polímero Teflon, já que sua energia de ligação correspondia principalmente à da espécie CF2. Além disso, usando a sinal C 1s, foi possível corroborar a presença do grupo CF2, o qual está associado ao componente principal das cadeias carbônicas do Teflon. O uso da informação obtida por XPS permitiu determinar que durante a desidratação do solvente (passo prévio para a obtenção dos catalisadores no qual são usados solventes orgânicos e alta temperatura) tem-se a contaminação com Teflon, já que este componente está presente em diversos acessórios utilizados no processo de desidratação, sendo a fita do Teflon e o agitador magnético as possíveis fontes da contaminação.