Evaluation of biocidal properties of biodegradable nanofiber filters and their use in face masks.

Due to the recent coronavirus-2019 pandemic, several studies have emerged looking for new materials, especially with biocidal characteristics. Thus, the present research investigates the antibacterial properties of biodegradable cellulose acetate (CA) / cetylpyridinium bromide (CPB) electrospun nanofibers, their aerosol filtration, and the possible use as a filter media of surgical face masks. Then, samples of these nanofibers were produced over a nonwoven substrate, using different volumes of polymeric solution during the electrospinning process. The evaluation of the antibacterial properties of the nanofibers was performed for Escherichia coli and Staphylococcus aureus using quantitative methods. The aerosol filtration performance was evaluated in these samples for NaCl nanoparticles (from 7-300 nm) and with 8 mL min-1 of air flow rate. The results show that the single use of the surfactant has antibacterial properties from a concentration of 39 µg mL-1 of solution. The nanofibers presented a reduction of 100% for both bacteria. Air filtration tests showed 126.03 and 207.73 Pa cm-² of pressure drops and 63 and 77% of aerosol filtration efficiency (FE) for samples with 0.13 and 0.15 mL, respectively. Regarding the nanofiber produced with 0.35 mL, the value obtained was 115.13 ± 33.64 Pa cm-2 and 3.15% of particle penetration. These breathability values are higher than those required for the surgical face mask standard, indicating that improvements in the porosity and thickness are necessary to meet the Brazilian requirements. However, the nanofibers could be applied as filter media for indoor air conditioning systems due to their FE and biocidal properties.

Modification and Functionalization of Fibers Formed by Electrospinning: A Review.

The development of new materials with specific functionalities for certain applications has been increasing with the advent of nanotechnology. A technique widely used for this purpose is electrospinning, because control of several parameters involved in the process can yield nanoscale fibers. In addition to the production of innovative and small-scale materials, through structural, chemical, physical, and biological modifications in the fibers produced in electrospinning, it is possible to obtain specific properties for a given application. Thus, the produced fibers can serve different purposes, such as in the areas of sensors, catalysis, and environmental and medical fields. Given this context, this article presents a review of the electrospinning technique, addressing the parameters that influence the properties of the fibers formed and some techniques used to modify them as specific treatments that can be conducted during or after electrospinning. In situ addition of nanoparticles, changes in the configuration of the metallic collector, use of alternating current, electret fibers, core/shell method, coating, electrospray-coating, plasma, reinforcing composite materials, and thermal treatments are some of the examples addressed in this work. Therefore, this work contributes to a better comprehension of some of the techniques mentioned in the literature so far.

Chemical characterization of PM2.5 from region highly impacted by hailstorms in South America.

The chemical composition of particulate material plays an important role in the atmosphere, providing cloud and ice nuclei for storm development. This study aims to evaluate and infer the sources of ions, metals, and metalloids in the fine atmospheric particulate matter (PM2.5) from triple border Paraná, Santa Catarina (Brazil), and northeastern Argentina, which is among those with the highest hail incidence in the world. Among the ions, the concentrations presented the following sequence in decreasing order: [Formula: see text]> K+> [Formula: see text]> [Formula: see text]> Ca2+> Cl-> Na+> Mg2+. Regarding the metals and metalloid concentrations, the order was of S > Si > Al > Fe > P > Ti, Cr, Cu, and Zn > Br > Mn, and Ni. The main sources, supported by positive matrix factorization results, are soil and agricultural activities, as well as vehicular emissions due to the agricultural machinery and the displacement of residents. Besides, the influence of aerosols from biomass burning and industrial activities was observed, possibly come from long-distance transport. The composition of PM2.5 presents one or more elements considered present ice nuclei (IN) activity, such as Al, Mn, Cu, Co, Ni, and V (in form of oxides), corroborating with other studies, also, with high hail incidence. However, further studies are needed to verify the role of aerosol characteristics in the formation of IN and, consequently, hail.

Evidence of leptospiral exposure in neotropical primates rescued from illegal trade and a Zoo in Bahia, Brazil / Indícios de exposição a leptospiras em primatas neotropicais resgatados do comércio ilegal e de um Zoológico da Bahia

Few studies have compared the seroprevalence of antileptospiral agglutinins with the demonstration of urinary shedding of leptospires or evidence of active infection in the bloodstreams of non-human primates. The study population consists of 58 animals, including d 42 monkeys from the Zoological Park of Salvador (Parque Zoobotânico Getúlio Vargas), Bahia, Brazil. The study also evaluated 16 primates (Cebus sp.) rescued from illegal trade that were housed in the Wildlife Rehabilitation Center of Salvador (CETAS), Bahia, Brazil. The seroprevalence of antileptospiral antibodies was low (2%) in the animals from the Zoo. A higher rate (31%) was observed among the animals that were rescued from illegal trade in the state of Bahia. Even if all the blood and urine samples were negative for leptospiral DNA fragments, the high frequency of serological evidence of exposure suggests a potential risk of leptospirosis transmission when keeping these animals as pets.(AU)

Poucos estudos compararam a soroprevalência de aglutininas antileptospira com a demonstração de excreção urinária de leptospiras ou evidência de infecção ativa em primatas não humanos. A população estudada consistiu em 58 animais, sendo 42 primatas do Parque Zoobotânico Getúlio Vargas, Bahia, Brasil. O estudo avaliou ainda 16 primatas (Cebus sp.) resgatados do tráfico ilegal e abrigados no Centro de Triagem de Animais Silvestres Chico Mendes, Salvador, Bahia, Brasil. A soroprevalência de anticorpos antileptospira foi baixa (2%) nos animais do Zoológico. Uma taxa mais elevada (31%) foi observada nos animais resgatados do tráfico ilegal. Mesmo que todas as amostras de sangue e urina tenham sido negativas para DNA de leptospiras, a alta frequência de evidência de exposição nos animais de origem selvagem indicam o risco potencial da adoção de primatas como animais de estimação.(AU)

Second-Line Chemotherapy in Recurrent Glioblastoma: A 2-Cohort Study.

BACKGROUND: Glioblastoma (GB) is the most common malignant primary central nervous system tumor in adults. Standard-of-care therapy includes surgical resection, radiotherapy and temozolomide, but nearly all patients experience disease progression. The purpose of this study was to describe 2 cohorts of patients with recurrent GB submitted to second-line treatment with procarbazine/lomustine/vincristine (PCV) or bevacizumab/irinotecan (BI). MATERIAL AND METHODS: Retrospective analysis of GB patients treated in our center with PCV or BI, after progression with temozolomide, between 2004 and 2012. RESULTS: Among 60 patients, 41 were treated with BI and 19 with PCV. According to the Macdonald criteria, the overall response rate in the BI group was 66% (n = 27) while it was 11% (n = 2) in the PCV group. The median progression-free survival was 5 and 3 months in the BI and PCV group, respectively. The median overall survival (OS) since second-line chemotherapy was 9 months in the BI group and 5 months in the PCV group. The latter group had a worse toxicity profile (grade 3-4: 52.6% vs. 22.0%; grade 1-2: 89.5% vs. 68.3%). CONCLUSIONS: The BI cohort had higher response rates, almost twice the OS and a lower degree of toxicity in contrast to the PCV group. The small number of patients and historical cohorts limits these comparisons.

Detection of anti-Leptospira antibodies in captive nonhuman primates from Salvador, Brazil.

Leptospirosis is a widely distributed zoonosis that affects several species of domestic and wild animals. Under captive conditions, Leptospirosis is a potential problem because the physical conditions in most zoos and research centers cannot prevent the captive animals from being exposed to rodents, raccoons, opossums, and other local wildlife that are known carriers. Yet, despite the potential risk, animals that are destined for reintroduction into the wild are not routinely tested for anti-Leptospira antibodies before their release. The purpose of this study was to determine the occurrence of anti-Leptospira antibodies in captive New World monkeys that were housed in the Wild Animals Screening Center in Salvador, Brazil. Blood samples were collected from 44 monkeys (28 Callithrix jacchus, eight Callithrix pennicilata, and eight Cebus sp.). The animals were screened for antibodies with the microscopic agglutination test. Twenty-five (56.8%) primates were seroreactive, with Icterohaemorrhagiae being the most frequent serogroup. None of the monkeys, however, presented clinical signs of leptospirosis. Thus, seroreactivity with low titers in asymptomatic animals, as observed in this study, suggests exposure to the agent. The unexpected predominance of the serogroup Icterohaemorrhagiae further suggests that exposure to this serogroup occurred in captivity. Therefore, the dangerous possibility cannot be ignored that reintroduced monkeys will carry the leptospiral serovars into wild populations. In conclusion, primates exposed to urban serovars before their release from captivity represent a potentially significant health risk to wild populations.