chemical and spectroscopic characterization of insoluble and soluble humic acid fractions at different ph values

Background: Humic acids (HA) are organic molecules with complex structure and function and variable properties. They are insoluble in strongly acid pH conditions. At present, it is not clear how much is the amount of HA in solution at the pH of natural soils nor are known the characteristics of the different soluble fractions and their possible association with the inorganic phase of soil. The scope of this work was to characterize the soluble and insoluble fractions obtained by acidifying Na humate solution at pH values 3, 5, and 7 and to compare these fractions with the HA obtained at pH 1. At each pH, the precipitate and the soluble fractions were separated and characterized by elemental analysis, total acidity and carboxylic group content, infrared, and 13 C NMR and 1 H NMR spectroscopy. Results: The HA fraction insoluble at pH 1 had a high acid group content and aromaticity but a low content of Oand N-containing groups. At pH 3, a fraction with nearly the same characteristics was obtained. At pH 1 and pH 3, the inorganic phase bound to the insoluble humic material was largely constituted by clay minerals and some Al and Fe hydroxides. The soluble fractions at pH values 1 and 3 were very poor and they were composed of a silica gel-like phase associated with polar organic material rich in carboxylic and metal-carboxylate groups. At pH values 5 and 7, only a small fraction of the Na humates precipitated. The fractions remaining in the solution were mainly composed of organic material particularly rich in aromatic and aliphatic groups, while the inorganic phase contained phyllosilicates. The fractions insoluble at pH values 5 and 7 contained a large amount of inorganic material that consisted mainly of phyllosilicates. Conclusions: The soluble fractions obtained at pH values 5 and 7 represent the humic component that in environmental situations would be dissolved in the soil solution. Our findings could be very useful for a more detailed investigation into the way HA influence plant metabolism under environmental-like conditions, both as regards pH conditions and interaction with the mineral fraction

Effect of leguminous cover crops on soil biological activity in pots of Citrus unshiu Marcovitch

Little is known about the effects of cover crops on soil properties in citrus orchards. To fill this gap, this work was aimed to determine the effects of leguminous cover crops on the chemical and biological properties of the soil and on the structure of the microbial community in pots of Citrus unshiu (Marcovitch). After amendment with cover crops, an increase in total organic C (TOC), total extractable C (TEC), and total N (TN) contents were observed irrespective of the type of soil. Substrate induced respiration (SIR), and potentially mineralisable nitrogen (PMN), tested three times in one year, were higher in soils with leguminous cover crops while no significant differences were observed in protease and deaminase activity. The effect on the chemical and biochemical properties of the soil was more evident in plots containing Trifolium subterraneum. No changes were observed in the microbial communities studied (_-proteobacteria, _-proteobacteria, nitrogen-fixing, and ammonia oxidizers) irrespective of the kind of cover crop or type of soil, neither were variations noted during the trial

Ocorrência de anticorpos anti-Toxoplasma gondii, anti-Neospora caninum e anti-Leptospira spp. em gambás (Didelphis spp.) no estado de São Paulo, Brasil

Opossum (Didelphis spp.) is an omnivorous marsupial native to the Americas that shows synanthropic behavior in urban areas. Despite its proximity to domestic animals and humans, knowledge of its participation in the epidemiology of some zoonotic agents is substantial. This study aimed to determine the presence of antibodies against Toxoplasma gondii, Neospora spp. and Leptospira spp. in blood samples collected from opossums in 18 municipalities in the state of São Paulo, Brazil, between 2003 and 2008. Blood samples from 343 opossums: Didelphis aurita (n = 256) and Didelphis albiventris (n = 87) were obtained. These were tested to detect antibodies against T. gondii, using the modified agglutination test (MAT-Toto; cutoff ≥ 25); Neospora spp., using the indirect fluorescent antibody test (IFAT; cutoff ≥ 25); and Leptospira spp., using the microscopic agglutination test (MAT-Lepto; cutoff ≥ 100). Frequency of anti-T. gondii, Neospora spp. and Leptospira spp. antibodies were in 22.7%, 1.5% and 3.5%, respectively. The serogroups-serovars of Leptospira spp. presenting positive MAT-Lepto reactions were: Autumnalis-Butembo; Mini-Mini; Ballum-Castellonis; Icterohaemorrhagiae-Icterohaemorrhagiae; Icterohaemorrhagiae-Copenhageni and Grippotyphosa-Grippotyphosa or Bananal. This study demonstrated that these zoonotic agents are circulating in opossum populations in the state of São Paulo. Therefore, investigations regarding the role of marsupials in the epidemiology of each of these diseases should be conducted, especially to understand the behavior of these animals as zoonosis maintenance hosts. O gambá (Didelphis spp.) é um marsupial onívoro nativo das Américas que apresenta comportamento sinantrópico em áreas urbanas. Apesar da sua proximidade com animais domésticos e o homem, o conhecimento da sua participação na epidemiologia de alguns agentes zoonóticos é fundamental. Este estudo objetivou determinar a presença de anticorpos contra Toxoplasma gondii, Neospora spp. e Leptospira spp. em amostras de sangue colhidas de gambás de 18 municípios do estado de São Paulo, Brasil, entre 2003 e 2008. Foram obtidas amostras sanguíneas de 343 gambás: Didelphis aurita (n = 256) e Didelphis albiventris (n = 87). As amostras foram testadas para detecção de anticorpos contra T. gondii, utilizando o teste de aglutinação modificado (TAM-Toxo; ponto de corte ≥ 25); Neospora spp., utilizando a reação de imunofluorescência indireta (RIFI; ponto de corte ≥ 25); e Leptospira spp., utilizando a soroaglutinação microscópica (SAM-Lepto; ponto de corte ≥ 100). As frequências de anticorpos contra T. gondii, Neospora spp. e Leptospira spp. foram 22,7%, 1,5% e 3,5%, respectivamente. Os sorogrupos-sorovares de Leptospira spp. que apresentaram soropositividade foram: Autumnalis-Butembo; Mini-Mini; Ballum-Castellonis; Icterohaemorrhagiae-Icterohaemorrhagiae; Icterohaemorrhagiae-Copenhageni e Grippotyphosa-Grippotyphosa ou Bananal. Esse estudo demonstrou que esses agentes estão circulando em populações de gambás no estado de São Paulo. Desta forma, investigações que visam determinar o papel dos marsupiais na epidemiologia de cada doença devem ser conduzidas, especialmente visando o entendimento do comportamento desses animais como hospedeiros dessas zoonoses

Pre-Operative Continued Oral Anticoagulation Impact on Early Outcomes after Transcatheter Aortic Valve Implantation

Considering that there is a lack of evidence and guideline-based recommendations on the best preoperative oral anticoagulation management (OAC) for transcatheter aortic valve implantation (TAVI), this cohort study aimed to evaluate bleeding, access site complications, and early safety in patients undergoing TAVI on continued OAC therapy vs no-OAC therapy. Three-hundred forty-four patients submitted to a TAVI procedure (66.3% no-OAC vs 33.7% OAC) were consecutively enrolled. Primary endpoint was defined as in-hospital VARC-2 life-threatening or disabling bleeding. Secondary endpoints were in-hospital VARC-2 major vascular complications and VARC-2 early safety at 30 days. Propensity score matching analysis was performed to reduce potential distribution bias, resulting in 2 well-balanced groups (92 patients in each arm). In the overall cohort, mean age, median EuroScore II, and STS-score were 78.7±7.6 years, 2.9% (1.7-5.9), and 2.3% (1.6-3.6), respectively. Despite being older (78 ± 8 vs 80 ± 6, p = 0.004) and having higher STS score (2.1 vs 2.6, p = 0.001), patients on OAC had similar incidence of in-hospital VARC-2 life-threatening or disabling bleeding (1.3% vs. 0.9%, p = 0.711), major vascular complications (4.8% vs 5.2%, p = 0.888), and VARC-2 early safety at 30 days (10.1% vs 12.1%, p = 0.575). No significant differences in the main outcomes were observed when propensity score matching was applied. In conclusion, the management of patients on OAC submitted to a TAVI procedure is challenging and requires balancing the risk of bleeding with the risk of thromboembolic events. The present study suggests that continued OAC was not associated with increased in-hospital VARC-2 life-threatening or disabling bleeding, major vascular complications, and VARC-2 early safety at 30 days

Ocorrência de parasitos gastrintestinais em fezes de gatos das cidades de São Paulo e Guarulhos

Fecal samples were collected from 138 cats with different sex and breeds captured from the streets of São Paulo and Guarulhos for the determination of gastrointestinal parasites infection. The animals were kept individually at Zoonosis Control Center at the cities of São Paulo (107 cats) and Guarulhos (31 cats). The feces were individually collected and examined by using sacarose solution flotation technique (d=1.203g/cm³). From the 138 samples, 80 (57.97%) were positive. Among the protozoa the most frequent agent was Cystoisospora felis in 36 cats (26.09%) followed by Cystoisospora rivolta in 34 cats (24.64%), Cryptosporidium parvum (1.45%) in two cats and Sarcocystis spp, in one cat (0.72%). Among the helminthes, Toxocara cati presented the high occurrence with 43 positive cats (31.16%), followed by Ancylostoma spp with 12 positive cats (8.70%) and Platynosomum fastosum in two cats (1.45%). Mixed infection were observed in 25 cats (18.12%) with T.cati and Cystoisospora spp. and T.cati and Ancylostoma spp, been the most common occurrence, both with 7.97% (11 samples) of occurrence.Amostras de fezes foram colhidas de 138 gatos, de idade, sexo e raça variadas, capturados nas ruas das cidades de São Paulo e Guarulhos, para determinação da presença de parasitos gastrintestinais. Os animais encontravam-se alojados individualmente no Centro de Controle de Zoonoses dos Municípios de São Paulo (107 gatos) e Guarulhos (31gatos). As fezes foram colhidas individualmente e processadas pela técnica de flutuação em solução de sacarose (d=1,203g/cm³). Dentre os protozoários o agente mais freqüente foi o Cystoisospora felis, em 36 gatos (26,09%), seguido pelo Cystoisospora rivolta, em 34 (24,64%), pelo Cryptosporidium parvum, em dois (1,45%) e pelo Sarcocystis spp. em um animal (0,72%). Dentre os helmintos, Toxocara cati foi o de maior ocorrência, com 39 gatos positivos (28,26%), seguido pelo Ancylostoma spp., com 12 gatos positivos (8,70%) e pelo Platynosomun fastosum em dois gatos (1,45%). A presença de proglotes de Dipylidium caninum foi observada em duas amostras, quando da colheita nas gaiolas, dado este certamente subestimado, uma vez que o encontro de cápsula ovígera em fezes é bastante raro, sendo o diagnóstico feito pela observação de proglotes nas fezes frescas. Os parasitos estavam presentes em infecções múltiplas em 25 animais (18,12%) sendo as ocorrências mais comuns T.cati com Cystoisospora spp. e T.cati com Ancylostoma spp., ambas com 7,97% de ocorrência (11 amostras)