Screening of Commercial Organic Solvent Nanofiltration Membranes for Purification of Plastic Waste Pyrolysis Liquids.

Increasing consumption rates of plastics, combined with the waste generated from their production, leads to several environmental problems. Presently, plastic recycling takes account of only about 10% of the plastic waste, which is achieved mainly through mechanical recycling. Chemical recycling methods, such as pyrolysis, could significantly increase overall recycling rates and reduce the need for the production of fossil-based chemicals. Produced pyrolysis oil can be used for the production of benzene, toluene and xylene (BTX) through catalytic upgrading or for the production of alkanes if used directly. Separation of high-value components in pyrolysis oil derived from plastic waste through traditional separation methods can be energy intensive. Organic solvent nanofiltration has been recognised as an alternative with very low energy consumption, as separation is not based on a phase transition. This work focuses on the screening of several (semi-) commercially available membranes using a simplified model mixture of pyrolysis oil obtained from plastics. Based on membrane performance, a selection of membranes was used to treat a feedstock obtained from the direct pyrolysis of plastics. This work shows that currently, commercial OSN membranes have promising separation performance on model mixtures while showing insufficient and non-selective separation at very low flux for complex mixtures derived from the pyrolysis of plastics. This indicates that OSN is indeed a promising technology but that membranes should likely be tailored to this specific application.

Bioinformatic and experimental characterization of SEN1998: a conserved gene carried by the Enterobacteriaceae-associated ROD21-like family of genomic islands.

Genomic islands (GIs) are horizontally transferred elements that shape bacterial genomes and contributes to the adaptation to different environments. Some GIs encode an integrase and a recombination directionality factor (RDF), which are the molecular GI-encoded machinery that promotes the island excision from the chromosome, the first step for the spread of GIs by horizontal transfer. Although less studied, this process can also play a role in the virulence of bacterial pathogens. While the excision of GIs is thought to be similar to that observed in bacteriophages, this mechanism has been only studied in a few families of islands. Here, we aimed to gain a better understanding of the factors involved in the excision of ROD21 a pathogenicity island of the food-borne pathogen Salmonella enterica serovar Enteritidis and the most studied member of the recently described Enterobacteriaceae-associated ROD21-like family of GIs. Using bioinformatic and experimental approaches, we characterized the conserved gene SEN1998, showing that it encodes a protein with the features of an RDF that binds to the regulatory regions involved in the excision of ROD21. While deletion or overexpression of SEN1998 did not alter the expression of the integrase-encoding gene SEN1970, a slight but significant trend was observed in the excision of the island. Surprisingly, we found that the expression of both genes, SEN1998 and SEN1970, were negatively correlated to the excision of ROD21 which showed a growth phase-dependent pattern. Our findings contribute to the growing body of knowledge regarding the excision of GIs, providing insights about ROD21 and the recently described EARL family of genomic islands.

Novel Template Plasmids pCyaA'-Kan and pCyaA'-Cam for Generation of Unmarked Chromosomal cyaA' Translational Fusion to T3SS Effectors in Salmonella.

The type III secretion systems (T3SS) encoded in pathogenicity islands SPI-1 and SPI-2 are key virulence factors of Salmonella. These systems translocate proteins known as effectors into eukaryotic cells during infection. To characterize the functionality of T3SS effectors, gene fusions to the CyaA' reporter of Bordetella pertussis are often used. CyaA' is a calmodulin-dependent adenylate cyclase that is only active within eukaryotic cells. Thus, the translocation of an effector fused to CyaA' can be evaluated by measuring cAMP levels in infected cells. Here, we report the construction of plasmids pCyaA'-Kan and pCyaA'-Cam, which contain the ORF encoding CyaA' adjacent to a cassette that confers resistance to kanamycin or chloramphenicol, respectively, flanked by Flp recombinase target (FRT) sites. A PCR product from pCyaA'-Kan or pCyaA'-Cam containing these genetic elements can be introduced into the bacterial chromosome to generate gene fusions by homologous recombination using the Red recombination system from bacteriophage λ. Subsequently, the resistance cassette can be removed by recombination between the FRT sites using the Flp recombinase. As a proof of concept, the plasmids pCyaA'-Kan and pCyaA'-Cam were used to generate unmarked chromosomal fusions of 10 T3SS effectors to CyaA' in S. Typhimurium. Each fusion protein was detected by Western blot using an anti-CyaA' monoclonal antibody when the corresponding mutant strain was grown under conditions that induce the expression of the native gene. In addition, T3SS-1-dependent secretion of fusion protein SipA-CyaA' during in vitro growth was verified by Western blot analysis of culture supernatants. Finally, efficient translocation of SipA-CyaA' into HeLa cells was evidenced by increased intracellular cAMP levels at different times of infection. Therefore, the plasmids pCyaA'-Kan and pCyaA'-Cam can be used to generate unmarked chromosomal cyaA' translational fusion to study regulated expression, secretion and translocation of Salmonella T3SS effectors into eukaryotic cells.

A comparative proteomic analysis of Candida species in response to the oxidizing agent cumene hydroperoxide.

Candida genus comprises several species that can be found in the oral cavity and the gastrointestinal and genitourinary tracts of healthy individuals. Under certain conditions, however, they behave as opportunistic pathogens that colonize these tissues, most frequently when the immune system is compromised by a disease or under certain medical treatments. To colonize the human host, these organisms require to express cell wall proteins (CWP) that allowed them to adhere and adapt to the reactive oxygen (ROS) and nitrogen (RNS) species produced in the macrophage during the respiratory burst. The aim of this study was to determine how four Candida species respond to the oxidative stress imposed by cumene hydroperoxide (CHP). To this purpose, C. albicans, C. glabrata, C. krusei and C. parapsilosis were exposed to this oxidant which is known to generate ROS in the membrane phospholipids. Accordingly, both mock and CHP-exposed cells were used to extract and analyze CWP and also to measure catalase activity and the levels of protein carbonylation. Results indicated that all four species express different CWP to neutralize ROS. Most relevant among these proteins were the glycolytic enzymes enolase and glyceraldehyde-3-phosphate dehydrogenase, known as moonlight proteins because in addition to participate in glycolysis they play an important role in the cell response to ROS. In addition, a thiol-specific antioxidant enzyme (Tsa) was also found to counteract ROS.

Experimental Evaluation of Anion Exchange Membranes for the Desalination of (Waste) Water Produced after Polymer-Flooding.

Electrodialysis (ED) has been recently proposed to desalinate polymer-flooding produced water (PFPW), a byproduct stream from the oil and gas industry rich in charged polymers. However, process performance is limited by fouling occurring on the ion-exchange membranes, particularly on the anionic ones (AEMs). Thus, this study aimed to correlate the properties of different AEMs with their performance while desalinating PFPW, ultimately evaluating their significance when fouling is to be minimized and operation improved. Six stacks containing different homogeneous and commercially available AEMs were employed to desalinate synthetic PFPW during 8-days ED experiments operated in reversal mode. AEMs recovered from the stacks were analyzed in terms of water uptake, ion-exchange capacity, permselectivity, and area resistance, and compared with virgin AEMs. Relatively small changes were measured for most of the parameters evaluated. For most AEMs, the water uptake and resistance increased, while the ion-exchange capacity (IEC) and permselectivity decreased during operation. Ultimately, AEMs with high area resistance were linked to the fast development of limiting current conditions in the stack, so this property turned out to be the most relevant when desalinating PFPW.

Development of an instrument to measure the cultural competence of health care workers.

OBJECTIVE: To validate an instrument measuring the cultural competence in health care workers from Chile. METHODS: Using Sue & Sue's theoretical model of cultural competence, we designed a scale, which was assessed by health care workers and experts. Subsequently, the scale was applied to a sample of 483 different health care workers, during 2018 in Santiago de Chile. The analysis included: exploratory and confirmatory factor analysis, estimation of reliability, and analysis of measurement bias. Finally, the level of cultural competence was calculated for every professional who participated in this study. RESULTS: The final scale include 14 items that are grouped into three dimensions concordant with the theoretical model: sensitivity to own prejudices, cultural knowledge, and skills to work in culturally diverse environments. This scale showed good fit in factor models, adequate reliability and lack of evidence of measurement bias. Regarding the performance of health care workers, sensitivity showed a lower level compared with the other dimensions evaluated. CONCLUSION: The scale for measuring the level of cultural competence in health care workers (EMCC-14) is a reliable instrument, with initial support for its validity, which can be used in the Chilean context. Additionally, the results of this study could guide some possible interventions in the health sector to strengthen the level of cultural competence.

Antibiotic resistance in bacterial isolates from freshwater samples in Fildes Peninsula, King George Island, Antarctica.

Anthropic activity in Antarctica has been increasing considerably in recent years, which could have an important impact on the local microbiota affecting multiple features, including the bacterial resistome. As such, our study focused on determining the antibiotic-resistance patterns and antibiotic-resistance genes of bacteria recovered from freshwater samples collected in areas of Antarctica under different degrees of human influence. Aerobic heterotrophic bacteria were subjected to antibiotic susceptibility testing and PCR. The isolates collected from regions of high human intervention were resistant to several antibiotic groups, and were mainly associated with the presence of genes encoding aminoglycosides-modifying enzymes (AMEs) and extended-spectrum ß-lactamases (ESBLs). Moreover, these isolates were resistant to synthetic and semi-synthetic drugs, in contrast with those recovered from zones with low human intervention, which resulted highly susceptible to antibiotics. On the other hand, we observed that zone A, under human influence, presented a higher richness and diversity of antibiotic-resistance genes (ARGs) in comparison with zones B and C, which have low human activity. Our results suggest that human activity has an impact on the local microbiota, in which strains recovered from zones under anthropic influence were considerably more resistant than those collected from remote regions.

Development of an instrument to measure the cultural competence of health care workers / Desarrollo de un instrumento para medir competencia cultural en trabajadores de Salud

ABSTRACT OBJECTIVE To validate an instrument measuring the cultural competence in health care workers from Chile. METHODS Using Sue & Sue's theoretical model of cultural competence, we designed a scale, which was assessed by health care workers and experts. Subsequently, the scale was applied to a sample of 483 different health care workers, during 2018 in Santiago de Chile. The analysis included: exploratory and confirmatory factor analysis, estimation of reliability, and analysis of measurement bias. Finally, the level of cultural competence was calculated for every professional who participated in this study. RESULTS The final scale include 14 items that are grouped into three dimensions concordant with the theoretical model: sensitivity to own prejudices, cultural knowledge, and skills to work in culturally diverse environments. This scale showed good fit in factor models, adequate reliability and lack of evidence of measurement bias. Regarding the performance of health care workers, sensitivity showed a lower level compared with the other dimensions evaluated. CONCLUSION The scale for measuring the level of cultural competence in health care workers (EMCC-14) is a reliable instrument, with initial support for its validity, which can be used in the Chilean context. Additionally, the results of this study could guide some possible interventions in the health sector to strengthen the level of cultural competence.

RESUMEN OBJETIVO Validar un instrumento de medición de competencia cultural en trabajadores de salud de Chile. MÉTODOS Utilizando el modelo teórico de Sue y Sue, se diseñó un instrumento de medición el cual fue evaluado por trabajadores de salud y expertos. Este instrumento se aplicó a una muestra diversa de 483 proveedores de salud, durante 2018 en Santiago de Chile. Se realizó análisis factorial exploratorio, confirmatorio, estimación de confiabilidad y análisis de sesgo de medición. Se estimó el nivel de competencia cultural alcanzado por los profesionales. RESULTADOS El instrumento final contó con 14 ítems los cuales se agruparon en tres dimensiones: sensibilidad a los propios prejuicios, conocimiento cultural y habilidades para trabajar en entornos culturalmente diversos. Esta herramienta mostró buen ajuste en los modelos factoriales, adecuada confiabilidad y ausencia de evidencias de sesgo de medición. Los trabajadores de salud evaluados exhibieron un bajo nivel de sensibilidad a los propios prejuicios en comparación con las otras dimensiones evaluadas. CONCLUSIONE La Escala de Medición de Competencia Cultural en trabajadores de salud (EMCC-14) es una herramienta confiable, con soporte inicial para su validez, que puede usarse en el contexto Chileno. Además, los resultados de este estudio podrían guiar algunas posibles intervenciones en el sector de la salud para fortalecer el nivel de competencia cultural.

Structure-Based Design of MptpB Inhibitors That Reduce Multidrug-Resistant Mycobacterium tuberculosis Survival and Infection Burden in Vivo.

Mycobacterium tuberculosis protein-tyrosine-phosphatase B (MptpB) is a secreted virulence factor that subverts antimicrobial activity in the host. We report here the structure-based design of selective MptpB inhibitors that reduce survival of multidrug-resistant tuberculosis strains in macrophages and enhance killing efficacy by first-line antibiotics. Monotherapy with an orally bioavailable MptpB inhibitor reduces infection burden in acute and chronic guinea pig models and improves the overall pathology. Our findings provide a new paradigm for tuberculosis treatment.

Fnr and ArcA Regulate Lipid A Hydroxylation in Salmonella Enteritidis by Controlling lpxO Expression in Response to Oxygen Availability.

Lipid A is the bioactive component of lipopolysaccharide, and presents a dynamic structure that undergoes modifications in response to environmental signals. Many of these structural modifications influence Salmonella virulence. This is the case of lipid A hydroxylation, a modification catalyzed by the dioxygenase LpxO. Although it has been established that oxygen is required for lipid A hydroxylation acting as substrate of LpxO in Salmonella, an additional regulatory role for oxygen in lpxO expression has not been described. The existence of this regulation could be relevant considering that Salmonella faces low oxygen tension during infection. This condition leads to an adaptive response by changing the expression of numerous genes, and transcription factors Fnr and ArcA are major regulators of this process. In this work, we describe for the first time that lipid A hydroxylation and lpxO expression are modulated by oxygen availability in Salmonella enterica serovar Enteritidis (S. Enteritidis). Biochemical and genetic analyses indicate that this process is regulated by Fnr and ArcA controlling the expression of lpxO. In addition, according to our results, this regulation occurs by direct binding of both transcription factors to specific elements present in the lpxO promoter region. Altogether, our observations revealed a novel role for oxygen acting as an environment signal controlling lipid A hydroxylation in S. Enteritidis.

O-antigen chain-length distribution in Salmonella enterica serovar Enteritidis is regulated by oxygen availability.

Lipopolysaccharide (LPS) consists of three covalently linked domains: the lipid A, the core region and the O antigen (OAg), consisting of repeats of an oligosaccharide. Salmonella enterica serovar Enteritidis (S. Enteritidis) produces a LPS with two OAg preferred chain lengths: a long (L)-OAg controlled by WzzSE and a very long (VL)-OAg controlled by WzzfepE. In this work, we show that OAg produced by S. Enteritidis grown in E minimal medium also presented two preferred chain-lengths. However, a simultaneous and opposing change in the production of L-OAg and VL-OAg was observed in response to oxygen availability. Biochemical and genetics analyses indicate that this process is regulated by transcriptional factors Fnr and ArcA by means of controlling the transcription of genes encoding WzzSE and WzzfepE in response to oxygen availability. Thus, our results revealed a sophisticated regulatory mechanism involved in the adaptation of S. Enteritidis to one of the main environmental cues faced by this pathogen during infection.

Overexpression of LOXIN Protects Endothelial Progenitor Cells From Apoptosis Induced by Oxidized Low Density Lipoprotein.

Human endothelial progenitor cells (hEPC) are adult stem cells located in the bone marrow and peripheral blood. Studies have indicated that hEPC play an important role in the recovery and repair of injured endothelium, however, their quantity and functional capacity is reduced in several diseases including hypercholesterolemia. Recently, it has been demonstrated that hEPC express lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) and its activation by oxidized low-density lipoprotein (ox-LDL) induces cellular dysfunction and apoptosis. This study aimed to investigate whether overexpression of LOXIN, a truncated isoform of LOX-1 that acts as a dominant negative, plays a protective role against ox-LDL-induced apoptosis in hEPC. Human endothelial progenitor cells exposed to ox-LDL showed a significant increase in LOX-1 expression, and apoptosis began at ox-LDL concentrations above 50 µg/mL. All hEPC apoptosed at 200 µg/mL ox-LDL. High LOXIN expression was generated using adenoviral systems in hEPC and SiHa cells transduced with 100 colony-forming units per cell. Transduced LOXIN localized to the plasma membrane and blocked ox-LDL uptake mediated by LOX-1. Overexpression of LOXIN protected hEPC from ox-LDL-induced apoptosis, and therefore maybe a novel way of improving hEPC function and quantity. These results suggest that adenoviral vectors of LOXIN may provide a possible treatment for diseases related to ox-LDL and vascular endothelium dysfunction, including atherosclerosis.

Epidemiología de neutropenia febril en pacientes adultos con leucemia aguda y linfoma: Estudio de cohorte en hospitales público y privado de Santiago, Chile / Epidemiology of febrile neutropenia in adult patients with acute leukemia and lymphoma: Cohort study of public and private hospital of Santiago, Chile

Introduction: Febrile neutropenia (FN) is a common complication of patients undergoing chemotherapy (QMT). Clinical presentation is varied, from mild fever to severe sepsis with invasive bacterial infection (IBI) or invasive fungal infection (IFI), with great impact on prognosis and patient mortality. Patients and Methods: Prospective cohort study of FN episodes in adult patients with acute leukemia (AL) or lymphoma (L), diagnosed and treated at the Hospital Clínico Universidad Católica and Hospital Dr. Sótero del Río in Santiago from April 2010 to January 2012. Results: 130 patients were included with 105 episodes of NF, with an incidence of 0.65 per 100 days of observation, higher in AL than L (1.31 vs 0.25, p = 0.001). Etiology or clinical focus was documented in 67 (63.8%) episodes, with IBI in 33 (31.4%) and IFI in 21 (20%) cases. Mortality related to infection occurred in 4 (6.2%) patients. Conclusions: This study reports that the FN incidence and frequency of IBI and IFI during episodes are higher in AL vs. L. It is necessary to evaluate the impact of interventions to reduce its incidence, including the benefit and risk of using antibacterial and antifungal prophylaxis in high-risk subgroups.

Introducción: La neutropenia febril (NF) es una complicación frecuente de pacientes sometidos a quimioterapia (QMT). Su presentación clínica es amplia, desde cuadros leves a sepsis grave con infección bacteriana invasora (IBI) o infección fúngica invasora (IFI), con gran impacto en el pronóstico y mortalidad de los pacientes. Pacientes y Métodos: Estudio prospectivo de episodios de NF en cohorte de pacientes adultos con leucemia aguda (LA) o linfoma (L) diagnosticados y tratados en el Hospital Clínico Pontificia Universidad Católica de Chile y Hospital Dr. Sótero del Río en Santiago, desde abril de 2010 hasta enero de 2012. Resultados: Se reclutaron 130 pacientes que presentaron 105 episodios de NF, con incidencia de 0,65 por 100 días de observación, mayor en LA que en L (1,31 vs 0,25, p: 0,001), documentándose etiología o foco infeccioso en 67 (63,8%) de los episodios, con 33 (31,4%) IBI y 21 (20%) IFI. Hubo mortalidad relacionada a infección en 4 (6,2%) pacientes. Conclusiones: Se define la incidencia de NF (LA > L) y frecuencia de IBI e IFI durante el episodio (LA > L). Es necesario evaluar el impacto de intervenciones destinadas a disminuir la incidencia de NF, entre las que se debe incluir el beneficio y riesgo del uso sistemático de profilaxis antibacteriana y antifúngica en los subgrupos de mayor riesgo.

Endothelium trans differentiated from Wharton's jelly mesenchymal cells promote tissue regeneration: potential role of soluble pro-angiogenic factors.

BACKGROUND: Mesenchymal stem cells have a high capacity for trans-differentiation toward many adult cell types, including endothelial cells. Feto-placental tissue, such as Wharton's jelly is a potential source of mesenchymal stem cells with low immunogenic capacity; make them an excellent source of progenitor cells with a potential use for tissue repair. We evaluated whether administration of endothelial cells derived from mesenchymal stem cells isolated from Wharton's jelly (hWMSCs) can accelerate tissue repair in vivo. METHODS: Mesenchymal stem cells were isolated from human Wharton's jelly by digestion with collagenase type I. Endothelial trans-differentiation was induced for 14 (hWMSC-End14d) and 30 (hWMSC-End30d) days. Cell phenotyping was performed using mesenchymal (CD90, CD73, CD105) and endothelial (Tie-2, KDR, eNOS, ICAM-1) markers. Endothelial trans-differentiation was demonstrated by the expression of endothelial markers and their ability to synthesize nitric oxide (NO). RESULTS: hWMSCs can be differentiated into adipocytes, osteocytes, chondrocytes and endothelial cells. Moreover, these cells show high expression of CD73, CD90 and CD105 but low expression of endothelial markers prior to differentiation. hWMSCs-End express high levels of endothelial markers at 14 and 30 days of culture, and also they can synthesize NO. Injection of hWMSC-End30d in a mouse model of skin injury significantly accelerated wound healing compared with animals injected with undifferentiated hWMSC or injected with vehicle alone. These effects were also observed in animals that received conditioned media from hWMSC-End30d cultures. CONCLUSION: These results demonstrate that mesenchymal stem cells isolated from Wharton's jelly can be cultured in vitro and trans-differentiated into endothelial cells. Differentiated hWMSC-End may promote neovascularization and tissue repair in vivo through the secretion of soluble pro-angiogenic factors.

[Epidemiology of febrile neutropenia in adult patients with acute leukemia and lymphoma: Cohort study of public and private hospital of Santiago, Chile]. / Epidemiología de neutropenia febril en pacientes adultos con leucemia aguda y linfoma: Estudio de cohorte en hospitales público y privado de Santiago, Chile.

INTRODUCTION: Febrile neutropenia (FN) is a common complication of patients undergoing chemotherapy (QMT). Clinical presentation is varied, from mild fever to severe sepsis with invasive bacterial infection (IBI) or invasive fungal infection (IFI), with great impact on prognosis and patient mortality. PATIENTS AND METHODS: Prospective cohort study of FN episodes in adult patients with acute leukemia (AL) or lymphoma (L), diagnosed and treated at the Hospital Clínico Universidad Católica and Hospital Dr. Sótero del Río in Santiago from April 2010 to January 2012. RESULTS: 130 patients were included with 105 episodes of NF, with an incidence of 0.65 per 100 days of observation, higher in AL than L (1.31 vs 0.25, p = 0.001). Etiology or clinical focus was documented in 67 (63.8%) episodes, with IBI in 33 (31.4%) and IFI in 21 (20%) cases. Mortality related to infection occurred in 4 (6.2%) patients. CONCLUSIONS: This study reports that the FN incidence and frequency of IBI and IFI during episodes are higher in AL vs. L. It is necessary to evaluate the impact of interventions to reduce its incidence, including the benefit and risk of using antibacterial and antifungal prophylaxis in high-risk subgroups.

Adenosine A2A and A3 receptors are involved in the human endothelial progenitor cells migration.

Human endothelial progenitor cells (hEPC) are recruited to sites of neovascularization where they differentiate into endothelial cells. The signals/factors responsible for hEPC migration and adhesion to sites of injury are not well understood. Elevated levels of adenosine are known to increase mature endothelial cell migration in response to tissue injury. However, the understanding of the role of adenosine in the physiology of hEPC is very limited. Using quantitative polymerase chain reaction and western blot analyses, we detected the expression of the adenosine receptors A2A, A2B, and A3 in hEPC. Stimulation of adenosine receptors using adenosine or the nonselective agonist adenosine-5'-N-ethylcarboxamide (NECA) increased hEPC migration in 1.4-fold and 2.1-fold (P < 0.01), respectively. Stimulation of hEPC using the A2A-specific agonist CGS-21680 resembled the effect observed in migration when using adenosine or NECA. Consequently, NECA and CGS-21680-stimulated migration of hEPC were reverted using the A2A receptor antagonist ZM-241385. NECA-stimulated migration was inhibited in dose-dependent manner using MRS-1523 (Ki of 147 ± 0.016 nM), MRS-1754 (Ki of 1900 ± 0.02 nM), or ZM-241385 (Ki of 0.2 ± 0.01 nM). In conclusion, adenosine stimulates hEPC migration by activating A2A and A3 but not A2B receptors and provides evidence to support a role of adenosine in modulating angiogenic capacity of hEPC.