Prediction of pollutant emission characteristics in ISO50001 energy management in the Americas: Uni and multivariate machine learning approach.

The American continent is experiencing significant economic and industrial development driven by sustainability principles. In this context, discussions on improving energy consumption have become increasingly frequent and dynamic across various sectors of civil society, including the implementation of energy efficiency measures as advocated by the ISO50001 energy management standard. However, there is a pressing need to investigate which socioeconomic aspects are responsible for the issuance of this certification in the Americas and how these factors relate to characteristic industrial emissions, especially particulate matter. This study aims to evaluate the socioeconomic factors influencing ISO50001 standard issuance and how these adjusted factors correlate with particulate matter of 2.5 µm and 10 µm dimensions. To achieve this, machine learning techniques were employed, considering the complex nature and risk of data overfitting. Model fitting was performed through multiple lasso regression, and the relationship between the adjusted factors was examined through cross-correlation analysis. The analyses indicate a strong correlation of adjusted macroeconomic indicators, especially with PM2.5, suggesting an association with cardiorespiratory problems and methane-related origins. This work is of great relevance to academia as it proposes new concepts regarding the interaction between energy efficiency standards and particulate matter. For the industrial sector, the adjusted factors provide guidance for standard implementation while also helping to mitigate health issues. Additionally, for the government, these results can assist in formulating policies to address specific health problems related to this area.

Listeria monocytogenes in beef: a hidden risk.

Listeria monocytogenes in beef receives less attention compared to other pathogens such as Salmonella and Escherichia coli. To address this gap, we conducted a literature review focusing on the presence of L. monocytogenes in beef. This review encompasses the pathogenic mechanisms, routes of contamination, prevalence rates, and the laws and regulations employed in various countries. Our findings reveal a prevalence of L. monocytogenes in beef and beef products ranging from 2.5% to 59.4%. Notably, serotype 4b was most frequently isolated in cases of beef contamination during food processing, with the skinning and evisceration stages identified as critical points of contamination.

Magnetic carbon nanotubes modified with proteins and hydrophilic monomers: Cytocompatibility, in-vitro toxicity assays and permeation across biological interfaces.

Carbon nanotubes are promising materials for biomedical applications like delivery systems and tissue scaffolds. In this paper, magnetic carbon nanotubes (M-CNTs) covered with bovine serum albumin (M-CNTs-BSA) or functionalized with hydrophilic monomers (M-CNTs-HL) were synthesized, characterized, and evaluated concerning their interaction with Caco-2 cells. There is no comparison between these two types of functionalization, and this study aimed to verify their influence on the material's interaction with the cells. Different concentrations of the nanotubes were applied to investigate cytotoxicity, cell metabolism, oxidative stress, apoptosis, and capability to cross biomimetic barriers. The materials showed cytocompatibility up to 100 µg mL-1 and a hemolysis rate below 2 %. Nanotubes' suspensions were allowed to permeate Caco-2 monolayers for up to 8 h under the effect of the magnetic field. Magnetic nanoparticles associated with the nanotubes allowed estimation of permeation through the monolayers, with values ranging from 0.50 to 7.19 and 0.27 to 9.30 × 10-3 µg (equivalent to 0.43 to 6.22 and 0.23 to 9.54 × 10-2 % of the initially estimated mass of magnetic nanoparticles) for cells exposed and non-exposed to the magnets, respectively. Together, these results support that the developed materials are promising for applications in biomedical and biotechnological fields.

Biofilm-producing Escherichia coli O104:H4 overcomes bile salts toxicity by expressing virulence and resistance proteins.

We investigated bile salts' ability to induce phenotypic changes in biofilm production and protein expression of pathogenic Escherichia coli strains. For this purpose, 82 pathogenic E. coli strains isolated from humans (n = 70), and animals (n = 12), were examined for their ability to form biofilms in the presence or absence of bile salts. We also identified bacterial proteins expressed in response to bile salts using sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-electrophoresis) and liquid chromatography-mass spectrometry (LC-MS/MS). Lastly, we evaluated the ability of these strains to adhere to Caco-2 epithelial cells in the presence of bile salts. Regarding biofilm formation, two strains isolated from an outbreak in Republic of Georgia in 2009 were the only ones that showed a high and moderate capacity to form biofilm in the presence of bile salts. Further, we observed that those isolates, when in the presence of bile salts, expressed different proteins identified as outer membrane proteins (i.e. OmpC), and resistance to adverse growth conditions (i.e. F0F1, HN-S, and L7/L12). We also found that these isolates exhibited high adhesion to epithelial cells in the presence of bile salts. Together, these results contribute to the phenotypic characterization of E. coli O104: H4 strains.

Magnetic Particle Spray Mass Spectrometry.

In this work, the concept of magnetic particle spray mass spectrometry (MPS-MS) is reported for the first time. Magnetic sorbent particles are used to extract the analytes from a liquid sample. The particles are magnetically attracted to the tip of a magnetic probe that is positioned at the entrance of the mass spectrometer. A solvent is dispensed on the particles, and a high voltage promotes the formation of the Taylor cone around the particles agglomerate. Analytes are desorbed by the solvent, ionized, and analyzed by mass spectrometry. MPS-MS is totally in consonance with the green chemistry principle. A minimal consumption of sample (100 µL), solvent (34 µL), and magnetic sorbent (500 µg) is needed per analysis for an excellent performance of MPS-MS in terms of sensitivity and selectivity. The determination of amitriptyline, citalopram, clomipramine, chlorpromazine, doxepin, haloperidol, nortriptyline, and venlafaxine in human plasma samples using magnetic restricted-access carbon nanotubes was carried out as a proof of principle. Limits of quantification of 10 µg L-1 and correlation coefficients higher than 0.98 were obtained for all of the analytes. Limits of detection ranged from 0.43 to 2.82 µg L-1. Precision (as relative standard deviation) and accuracies (as relative error) ranged from 3.6 to 23.6%, as well as -12.8 to 18.7%, respectively. MPS-MS opens a new line of developments in the association of sample preparation with ambient ionization. New sorbents, device configurations, and physical and chemical conditions can also be analyzed for the analysis of many other analytes in different samples.

Optimizing the Antimicrobial Activity of Sodium Hypochlorite (NaClO) over Exposure Time for the Control of Salmonella spp. In Vitro.

Fish is a nutritionally rich product; however, it is easily contaminated by pathogenic microorganisms, such as Salmonella spp. Therefore, this study aimed to identify the best concentration of sodium hypochlorite (NaClO), exposure time, and water temperature that allow the most effective antimicrobial effect on the viable population of Salmonella spp. Thus, Salmonella Enteritidis ATCC 13076 and Salmonella Schwarzengrund were exposed to different time frames, ranging from 5 min to 38.5 min, temperatures between 5 and 38.5 °C, and NaClO concentrations ranging from 0.36 to 6.36 ppm, through a central composite rotational design experiment (CCRD). The results demonstrated that the ATCC strain exhibited a quadratic response to sodium hypochlorite when combined with exposure time, indicating that initial contact would already be sufficient for the compound's action to inhibit the growth of the mentioned bacteria. However, for S. Schwarzengrund (isolated directly from fish cultivated in aquaculture), both NaClO concentration and exposure time significantly influenced inactivation, following a linear pattern. This suggests that increasing the exposure time of NaClO could be an alternative to enhance Salmonella elimination rates in fish slaughterhouses. Thus, the analysis indicates that the Salmonella spp. strains used in in vitro experiments were sensitive to concentrations equal to or greater than the recommended ones, requiring a longer exposure time combined with the recommended NaClO concentration in the case of isolates from aquaculture.

Shoulder injuries in Brazilian professional football players: epidemiological analysis of 3828 games.

OBJECTIVES: Football is a globally played sport that poses potential risks for musculoskeletal injuries. Upper-limb injuries have a lower incidence rate than lower-limb injuries but can still cause absenteeism and performance impairment in football players. This descriptive epidemiological study aimed to evaluate and compare the epidemiological data on shoulder injuries among professional football players in two major Brazilian football championships. METHODS: Data were collected throughout the championships, and club physicians medically evaluated each player during official games using two online forms. The collected information included the player's age and position, injury diagnosis, laterality, location on the field where the injury occurred, playing time, imaging examinations performed, need for surgical treatment, time to return to play (TRP), and recurrence of the injury. The incidence of injuries was evaluated using the Federation Internationale de Football Association (FIFA) incidence formula. RESULTS: A total of 107 shoulder injuries were recorded (4.3% of all injuries), with a FIFA incidence of 0.847. Glenohumeral dislocations (GHDs) and acromioclavicular dislocations (ACDs) accounted for 37.38% and 35.51% of all shoulder injuries, respectively. Goalkeepers and defenders presented, respectively, a 2.15 and 1.57 times increased risk of suffering shoulder injuries, while attackers presented a 0.63 times decreased risk. Injury recurrence was observed in 14.95% of cases, with GHDs and ACDs showing recurrence rates of 35.00% and 5.26%, respectively. Surgery was performed in 9.35% of cases, with GHDs representing 50% of all surgeries. The average TRP was 22.37 days, with severe and major injuries accounting for 11.21% and 10.28% of all injuries, respectively. Goalkeepers had the highest average TRP of 36.15 days. Recurring injuries had a higher average TRP of 33.44 days compared to nonrecurring injuries, which had an average TRP of 20.43 days. Surgically treated injuries had the highest average TRP of 112.5 days. CONCLUSION: Shoulder injuries in the professional football scenario are of great concern due to the high recurrence rate and need for surgical treatment, which will lead to a long TRP. These findings emphasize the need to implement prevention protocols and effective treatments to reduce the consequences of such injuries, which are usually underestimated in this sport. LEVEL OF EVIDENCE: III.

Can Extraintestinal Pathogenic Escherichia coli with Heat Resistance Profile Overcome Nonthermal Technologies?

Ultraviolet-C light-emitting diode (UVC-LED) and ultrasound (US) are two nonthermal technologies with the potential to destroy pathogens. However, little is known about their effectiveness in strains with a history of heat resistance. Thus, this study aimed to evaluate the phenotype and genotype of heat-resistant extraintestinal pathogenic Escherichia coli (ExPEC) with heat resistance genes after the application of US, UVC-LED, and UVC-LED+US. For this, two central composite rotatable designs were used to optimize the UVC-LED and US conditions in four ExPEC isolated from beef. From the genome of these isolates obtained in a previous study, possible genes for UVC resistance were analyzed. Results showed that US was ineffective in reducing >0.30 log colony-forming unit/mL, and that when used after UVC-LED, it showed a nonsynergic or antagonistic effect. Also, UVC-LED had the greatest effect at the maximum dose (4950 mJ/cm2 from 1.65 mW/cm2 for 50 min). However, the strains showed some recovery after that, which could be implicated in the expression of genes included in SOS system genes, some others present in the transmissible Locus of Stress Tolerance (trxBC and degP), and others (terC). Thus, ExPEC can overcome the conditions used in this study for US, UVC-LED, and UVC-LED+US, probably due to the history of resistance to other cellular damage. The result of this study will contribute to future studies that aim to find better treatment conditions for each food product.

Prenatal androgenization (2D:4D) predictions of tennis match-play success in junior players: A search for physiological explanations.

AIM: This study aims to investigate the possible association between digit ratio (2D:4D) and match-play success (MPS) in junior tennis players. In addition, we consider the possible explanatory pathways of these associations in relation to psychological, strength, power, and hormonal parameters. METHODS: We performed a cross-sectional study, with a sample comprised of 64 male junior tennis players (11-18 years old). Digit ratio was calculated from direct finger measurements. In addition, we measured the ratio of wins by number of matches played in 5 years of official competition (MPS), handgrip strength (HGS), standing long jump (SLJ), training (in weekly hours), and expertise (number of years in official competition). Salivary testosterone and cortisol levels were measured before and after physical "challenge" tests. RESULTS: The 2D:4D correlated negatively with HGS and SLJ. MPS was also negatively associated with 2D:4D, but was positively correlated to HGS, expertise, training, and self-confidence (SC). Multiple linear regression showed 2D:4D and expertise were associated with MPS (43%-54%). None of the physical, or hormonal variables tested explained the links between 2D:4D and MPS. CONCLUSION: Therefore, the specific fitness components influenced by prenatal androgenization that moderate sports success remain unknown. Future studies should explore the interaction of 2D:4D, with tennis exercises as a challenge to induce hormonal change, the effect of pubertal stage, and the influence of aerobic endurance in determining MPS.

Construction and validation of the community health workers perception questionnaire on conditions amenable to physiotherapy in primary health care / Construção e validação do questionário de percepção dos Agentes Comunitários de Saúde sobre condições sensíveis à fisioterapia na Atenção Primária

Abstract Introduction Community health workers, like the physiotherapist, perform essential functions in primary health care, being an important element in the transformation of public policies. There are no reported studies investigating the knowledge of community health workers about health conditions amenable to physiotherapy intervention in primary health care. Objective To construct a questionnaire to investigate the perception of community health workers about health conditions that could be remedied by physiotherapy intervention in primary health care. Methods This was a methodological study in which it was initially an analysis matrix with the aim of encompassing the ideas contemplated in the questionnaire. To construct the instrument, a literature review was carried out, and health conditions treatable with physiotherapy in primary health care were chosen. To validate the content and appearance of the items, twelve physiotherapists specialized in primary health care judged the suitability of the items contained. The content validity index was used to determine the degree of agreement during the response analysis process. Subsequently, a semantic analysis was carried out through the understanding of the items by 15 community health workers. In the validation stage, two rounds of evaluation were carried out. Adjustments were made to 17 questions. Results The study investigated a questionnaire with 20 questions containing hypothetical situations of home visits, in which the resident's situation could or could not constitute a health risk amenable to physiotherapeutic intervention. Conclusion The community health workers perception instrument on health conditions amenable to physiotherapy intervention in primary health care proved to be valid for use in this context. The use of the instrument may contribute to the development of community health worker training programs, with the aim of facilitating team communication.

Resumo Introdução O Agente Comunitário de Saúde (ACS), assim como o fisioterapeuta, desencadeia funções fundamentais na Atenção Primária à Saúde (APS), sendo ele-mento importante na transformação de políticas públicas. Inexistem estudos que investiguem o conhecimento dos ACS sobre as condições de saúde sensíveis à inter-venção da fisioterapia na APS. Objetivo Construir um questionário de investigação da percepção dos ACS sobre as condições de saúde sensíveis à intervenção da fisioterapia na APS. Métodos Trata-se de um estudo metodológico no qual, inicialmente, construiu-se uma matriz de análise com o intuito de englobar as ideias contempladas no questionário. Para a construção do instrumento, realizou-se uma revisão da literatura, sendo eleitas condições de saúde sensíveis à intervenção da fisioterapia na APS. Para a validação de conteúdo e aparente dos itens, 12 fisioterapeutas especialistas em APS julgaram a adequação dos itens contidos. Utilizou-se o índice de validade de conteúdo para verificar o grau de concordância durante o processo de análise das respos-tas. Posteriormente, realizou-se análise semântica por meio da compreensão dos itens por 15 ACS. Na etapa de validação, foram realizadas duas rodadas de avaliação. Foram feitos ajustes em 17 questões. Resultados O estudo resultou em um questionário com 20 questões contendo situações hipotéticas de visitas domiciliares, cuja situação do morador poderia ou não configurar um risco à saúde sensível à intervenção fisioterapêutica. Conclusão O instrumento de percepção dos ACS sobre as condições de saúde sensíveis à intervenção da fisioterapia na APS mostrou-se válido para ser utilizado no contexto da APS. A utilização do instrumento poderá contribuir na elaboração de programas de capacitação dos ACS, com o intuito de facilitar a comunicação da equipe.

Harnessing Small-Molecule Analyte Detection in Complex Media: Combining Molecularly Imprinted Polymers, Electrolytic Transistors, and Machine Learning.

Small-molecule analyte detection is key for improving quality of life, particularly in health monitoring through the early detection of diseases. However, detecting specific markers in complex multicomponent media using devices compatible with point-of-care (PoC) technologies is still a major challenge. Here, we introduce a novel approach that combines molecularly imprinted polymers (MIPs), electrolyte-gated transistors (EGTs) based on 2D materials, and machine learning (ML) to detect hippuric acid (HA) in artificial urine, being a critical marker for toluene intoxication, parasitic infections, and kidney and bowel inflammation. Reduced graphene oxide (rGO) was used as the sensory material and molecularly imprinted polymer (MIP) as supramolecular receptors. Employing supervised ML techniques based on symbolic regression and compressive sensing enabled us to comprehensively analyze the EGT transfer curves, eliminating the need for arbitrary signal selection and allowing a multivariate analysis during HA detection. The resulting device displayed simultaneously low operating voltages (<0.5 V), rapid response times (≤10 s), operation across a wide range of HA concentrations (from 0.05 to 200 nmol L-1), and a low limit of detection (LoD) of 39 pmol L-1. Thanks to the ML multivariate analysis, we achieved a 2.5-fold increase in the device sensitivity (1.007 µA/nmol L-1) with respect to the human data analysis (0.388 µA/nmol L-1). Our method represents a major advance in PoC technologies, by enabling the accurate determination of small-molecule markers in complex media via the combination of ML analysis, supramolecular analyte recognition, and electrolytic transistors.

Bristow-Latarjet Surgery: A Current Overview in Brazil.

Objective To provide a current overview of the Bristow-Latarjet surgery in Brazil. Materials and Methods This cross-sectional study was based on an electronic questionnaire with 26 items, which was sent to active members of the Brazilian Society of Shoulder and Elbow Surgery (Sociedade Brasileira de Cirurgia do Ombro e Cotovelo, SBCOC, in Portuguese). The questionnaire addressed training, surgical technique, complications, and postoperative management. Results We sent the questionnaire to 845 specialists from April 20 to May 12, 2021, and 310 of them answered i in full. During their specialization, most specialists participated in up to ten Bristow-Latarjet procedures. The most frequent complication was graft fracture, while the most common technical difficulty was screw positioning. In total, 50.6% and 73.9% reported having experienced intraoperative and postoperative complications respectively; 57.1% declared performing subscapularis suture; 99.7% indicated postoperative immobilization; and 61.9% considered graft consolidation fundamental. Conclusion Most specialists participated in up to ten Bristow-Latarjet procedures during the specialization, but 13.5% of them graduated without participating in the surgery. The most frequent complication was graft fracture. The most common technical difficulty was screw positioning. Most participants prefer postoperative immobilization since they believe graft consolidation is essential to resume the practiced of sports. The highest complication rate occurred with specialists who have obtained their titles 11 to 15 years ago. In Brazil, the Southeast region is the largest producer of specialists and has the highest concentration of these professionals.

Biomarkers in psychiatric disorders.

Psychiatric disorders represent a significant socioeconomic and healthcare burden worldwide. Of these, schizophrenia, bipolar disorder, major depressive disorder and anxiety are among the most prevalent. Unfortunately, diagnosis remains problematic and largely complicated by the lack of disease specific biomarkers. Accordingly, much research has focused on elucidating these conditions to more fully understand underlying pathophysiology and potentially identify biomarkers, especially those of early stage disease. In this chapter, we review current status of this endeavor as well as the potential development of novel biomarkers for clinical applications and future research study.

Amiloidose nodular - relato de rara apresentação da amiloidose localizada cutânea / Nodular amyloidosis - report of a rare presentation of cutaneous localized amyloidosis

Contexto: Amiloidose é um grupo de doenças caracterizadas pelo depósito de proteínas fibrilares, denominadas substância amiloide. Podem ser divididas em formas localizadas ou sistêmicas, sendo que dentre as localizadas, a forma nodular é a mais rara. Descrição do caso: Relatamos o caso de amiloidose primária localizada cutânea nodular que se apresentou com nódulos violáceos no dorso, e placas acastanhadas na região cervical há 8 anos sem evidências de envolvimento sistêmico. Discussão: Como cerca de 1% a 7% dos casos de amiloidose nodular localizada cutânea podem evoluir com envolvimento sistêmico, o seguimento dos pacientes faz-se necessário. O tratamento não é obrigatório, a retirada das lesões pode ser feita se o paciente o desejar, contudo as recidivas são frequentes. Conclusões: Mesmo possuindo baixa prevalência, a amiloidose nodular deve ser reconhecida pelo risco de progredir para acometimento sistêmico e associação com discrasias plasmocitárias, como mieloma múltiplo.

Bristow-Latarjet Surgery: A Current Overview in Brazil / Cirurgia de Bristow-Latarjet: Um panorama atual do Brasil

Abstract Objective To provide a current overview of the Bristow-Latarjet surgery in Brazil. Materials and MethodsThis cross-sectional study was based on an electronic questionnaire with 26 items, which was sent to active members of the Brazilian Society of Shoulder and Elbow Surgery (Sociedade Brasileira de Cirurgia do Ombro e Cotovelo, SBCOC, in Portuguese). The questionnaire addressed training, surgical technique, complications, and postoperative management. Results We sent the questionnaire to 845 specialists from April 20 to May 12, 2021, and 310 of them answered i in full. During their specialization, most specialists participated in up to ten Bristow-Latarjet procedures. The most frequent complication was graft fracture, while the most common technical difficulty was screw positioning. In total, 50.6% and 73.9% reported having experienced intraoperative and postoperative complications respectively; 57.1% declared performing subscapularis suture; 99.7% indicated postoperative immobilization; and 61.9% considered graft consolidation fundamental. Conclusion Most specialists participated in up to ten Bristow-Latarjet procedures during the specialization, but 13.5% of them graduated without participating in the surgery. The most frequent complication was graft fracture. The most common technical difficulty was screw positioning. Most participants prefer postoperative immobilization since they believe graft consolidation is essential to resume the practiced of sports. The highest complication rate occurred with specialists who have obtained their titles 11 to 15 years ago. In Brazil, the Southeast region is the largest producer of specialists and has the highest concentration of these professionals.

Resumo Objetivo Traçar um panorama atual da cirurgia de Bristow-Latarjet no Brasil. Materiais e Métodos Estudo transversal no qual um questionário eletrônico com 26 perguntas sobre aspectos de formação, técnica cirúrgica, complicações e manejo pós-cirúrgico foi enviado a membros ativos da Sociedade Brasileira de Cirurgia do Ombro e Cotovelo (SBCOC). Resultados Entre 20 de abril e 12 de maio de 2021, o questionário foi enviado a 845 especialistas, e obteve-se 310 respostas completas. Durante a especialização, a maior parte dos especialistas participou de até dez procedimentos de Bristow-Latarjet. A complicação mais frequente foi a fratura do enxerto, e a dificuldade técnica, o posicionamento dos parafusos. Ao todo, 50,6% já tiveram complicações no intraoperatório; 73,9% já tiveram complicações no pós-operatório; 57,1% fazem a sutura do subescapular; 99,7% indicam a imobilização no pós-operatório; e 61,9% consideram a consolidação do enxerto fundamental. Conclusão A maior parte dos especialistas participou de até dez procedimentos de Bristow-Latarjet durante a especialização, mas 13,5% se formaram sem ter participado de nenhuma cirurgia. A complicação mais frequente foi a fratura do enxerto. A dificuldade técnica mais frequente foi o posicionamento dos parafusos. Imobilização no pós-operatório é a preferência da maioria dos participantes, que consideram fundamental a consolidação do enxerto para o retorno ao esporte. O maior número de complicações ocorreu com especialistas que obtiveram o título de 11 a 15 anos atrás. A região Sudeste é a maior formadora de especialistas e onde está concentrada a maior parte deles.

Efficacy of Quaternary Ammonium Compounds for Control of Individual and Mixed Cultures of Escherichia coli with High- and Low-Quaternary Ammonium Compounds Resistance.

Escherichia coli is a well-characterized micro-organism in scientific literature. Similarly, quaternary ammonium compounds (QACs) are historical sanitizers in food processing. However, the use of QACs has been questioned due to bacterial resistance in some studies. Therefore, this study aimed to compare effects of single and mixed cultures of E. coli strains of different serogroups with either high (six strains) or low (five strains) resistance to QACs. Twenty-five combinations of strains with either high (H)- or low (L)-QAC resistance were analyzed (H + H vs. L + L). After exposure to QAC, combinations with statistical differences (p < 0.05) compared with individuals were selected and an inactivation model determined using GInaFit®. Only one combination of two strains (C23 and C20) with low-QAC resistance (mixture T18) had greater resistance (p < 0.05) than the individual isolates. The combination T18 and individual strain C23 presented a Weibull model, whereas the other isolated strain (C20) presented a biphasic inactivation model with a shoulder. Whole genome sequencing determined that unlike C20, C23 carried yehW, which may have led to Weibull inactivation. Possibly, very rapid interaction of C20 with the QAC favored increased survival of C23 and overall persistence of the T18 mixture. Consequently, our results indicate that individual E. coli with low-QAC resistance can synergistically interfere with QAC inactivation.

Direct magnetic sorbent sampling flame atomic absorption spectrometry (DMSS-FAAS) for highly sensitive determination of trace metals.

A procedure of direct magnetic sorbent sampling in flame atomic absorption spectrometry (DMSS-FAAS) was developed in this work. Metal-loaded magnetic sorbents were directly inserted in the flame of the FAAS for direct metal desorption/atomization. Magnetic graphene oxide aerogel (M-GOA) particles were synthesized, characterized, and used as a proof-of-concept in the magnetic dispersive solid phase extraction of Pb2+ ions from water samples. M-GOA was selected because is a light and porous sorbent, with high adsorption capacity, that is quickly burned by the flame. Magnetic particles were directly inserted in the flame by using a metallic magnetic probe, thereby avoiding the need for a chemical elution step. As all the extracted Pb2+ ions arrive to the flame without passing through the nebulization system, a drastic increase in the analytical signal was achieved. The improvement in the sensitivity of the proposed method (DMSS-FAAS) for Pb2+ determination was at least 40 times higher than the conventional procedure in which the Pb2+ is extracted, eluted, and analyzed by conventional flame atomic absorption spectrometry (FAAS) via the nebulization system. The analytical curve was linear from 5.0 to 180.0 µg L-1 and the limit of detection was found to be 1.30 µg L-1. Background measurements were insignificant, and the atomic absorption peaks were narrow and reproducible. Precision assessed as a percentage of the relative standard deviation %RSD was found to be 17.4, 7.1, and 7.8% for 10, 70, and 180 µg L-1 levels, respectively. The method showed satisfactory results even in the presence of other ions (Al3+, Cr3+, Co2+, Cu2+, Fe3+, Mn2+, Ba2+, Mg2+, and Li+). The performance of the new system was also evaluated for Cd2+ ions, as well as by using other magnetic particles available in our lab: magnetic carbon nanotubes (M-CNTs), magnetic restricted access carbon nanotubes (M-RACNT), magnetic poly (methacrylic acid-co-ethylene glycol dimethacrylate) (M-PMA), magnetic nanoparticles coated with orange powder peel (M-OPP), and magnetic nanoparticles covered with SiO2 (M - SiO2). Analytical signals increased for both analytes in all sorbents (increases of about 4-37 times), attesting the high potential and applicability of the proposed method. Simplicity, high analytical frequency, high detectability and reproducibility, low cost, and possibility of being totally mechanized are the most relevant advantages.

Heat-resistant and biofilm-forming Escherichia coli in pasteurized milk from Brazil.

Escherichia coli harboring a transmissible locus of stress tolerance (tLST) and the ability to form biofilms represent a serious risk in dairy production. Thus, we aimed to evaluate the microbiological quality of pasteurized milk from two dairy producers in Mato Grosso, Brazil, with a focus on determining the possible presence of E. coli with heat resistance (60 °C/6 min), biofilm-forming potential phenotypes and genotypes, and antimicrobial susceptibility. For this, fifty pasteurized milk samples from producers named A and B were obtained for 5 weeks to investigate the presence of Enterobacteriaceae members, coliforms, and E. coli. For heat resistance, E. coli isolates were exposed to a water bath at 60 °C for 0 and 6 min. In antibiogram analysis, eight antibiotics belonging to six antimicrobial classes were analyzed. The potential to form biofilms was quantified at 570 nm, and curli expression by Congo Red was analyzed. To determine the genotypic profile, we performed PCR for the tLST and rpoS genes, and pulsed-field gel electrophoresis (PFGE) was used to investigate the clonal profile of the isolates. Thus, producer A presented unsatisfactory microbiological conditions regarding Enterobacteriaceae and coliforms for weeks 4 and 5, while all samples analyzed for producer B were contaminated at above-the-limit levels established by national and international legislation. These unsatisfactory conditions enabled us to isolate 31 E. coli from both producers (7 isolates from producer A and 24 isolates from producer B). In this way, 6 E. coli isolates (5 from producer A and 1 from producer B) were highly heat resistant. However, although only 6 E. coli showed a highly heat-resistant profile, 97% (30/31) of all E. coli were tLST-positive. In contrast, all isolates were sensitive to all antimicrobials tested. In addition, moderate or weak biofilm potential was verified in 51.6% (16/31), and the expression of curli and presence of rpoS was not always related to this biofilm potential. Therefore, the results emphasize the spreading of heat-resistant E. coli with tLST in both producers and indicate the biofilm as a possible source of contamination during milk pasteurization. However, the possibility of E. coli producing biofilm and surviving pasteurization temperatures cannot be ruled out, and this should be investigated.

Lead determination in commercial juice samples by direct magnetic sorbent sampling flame atomic absorption spectrometry (DMSS-FAAS).

The direct magnetic sorbent sampling flame atomic absorption spectrometry (DMSS-FAAS), recently proposed by our research group, was applied to determine the lead in soy-based juice, whole grape juice, reconstituted grape juice, and orange nectar samples. A dispersive solid phase extraction (d-SPE) of lead was carried out using a magnetic orange peel powder, developed and optimized by Gupta et al (2012), that was inserted into flame by FAAS with a magnetic probe. The limits of quantification (<4.6 µg L-1) were smaller than maximum residue limits established in Brazil. Good precisions and accuracies were obtained. DMSS-FAAS presented a sensitivity at least 14 times greater than the d-SPE followed by conventional FAAS analysis, wherein the analytes were extracted and desorbed, and the eluate was introduced in FAAS via nebulization system. Lead was easily quantified in juice samples at very low concentrations, with satisfactory figures of merit, and without the need of a mineralization step.