Historical Control Data of Spontaneous Pathological Findings in C57BL/6J Mice Used in 18-Month Dietary Carcinogenicity Assays.

A retrospective analysis in C57BL6/J mice used in dietary carcinogenicity studies was performed to determine the survival rate, causes of death and incidences of spontaneous non-tumoral and tumoral findings. Data were collected from 1600 mice from control dose groups of sixteen 18-month carcinogenicity assays performed between 2003 and 2021 at the same test facility with similar environmental conditions and experimental procedures. The survival rate was high in both sexes (81%-85%) and the causes of humane euthanasia or death were mainly non-tumoral (chronic ulcerative dermatitis, atrial thrombosis). Benign tumors were more frequent than malignant tumors and females were more affected than males. Pituitary gland adenoma in females, lymphoma, bronchioloalveolar adenoma, and harderian gland adenoma in both sexes were the most common tumors. Systemic amyloidosis, the most frequent non-tumoral lesion, was observed variably across studies without sex predilection. The analysis by cohort (3 time periods of 6 years) showed a tendency toward higher incidences of lymphoma and pituitary gland adenoma and lower incidences of amyloidosis over time. The results presented here provide for the first time a robust set of control historical data in untreated C57BL/6J mice kept for 18 months contributing to build in depth knowledge of this animal model.

A stronger antibody response in increased disease severity of SARS-CoV-2.

BACKGROUND: An assessment of the factors that interfere with serum levels and the persistence of anti-SARs-CoV-2 IgG antibodies is essential in order to estimate the risk of reinfection and to plan vaccination. We analyzed the impact of the severity of coronavirus disease 2019 (COVID-19) and the clinical and biological factors regarding the persistence of SARs-CoV-2 anti-spike protein (IgG-S) antibodies at 12 months. METHODS: This was an observational, longitudinal study with individuals who had recovered from COVID-19 between August 2020 and June 2021. Peripheral blood samples were collected from volunteers who were hospitalized (SERIOUS COVID-19) and those who required no hospitalization (COVID-19 LIGHT). Samples were grouped according to days after symptom onset: up to 90, between 91 and 180, ≥ 180 days after symptom onset. A semiquantitative test for IgG anti-spike protein S1(IgG-S1) was used. RESULTS: We analyzed 238 individuals who had recovered from COVID-19, of whom 87 had been hospitalized and 151 had not. They provided 148 and 220 samples, respectively. Among those hospitalized, males (65.5%), volunteers aged over 60 years (41.1%), comorbidities such as arterial hypertension (67.8%) and diabetes mellitus (37.9%) were most frequent. We observed higher median serum IgG-S1 titers among those who had recovered from COVID-19 and had been hospitalized, at all collection time intervals (p < 0.001). We observed a weak correlation of increasing age with humoral IgG-S1 response (Spearman correlation = 0.298). There was a greater probability of IgG-S1 antibody persistence over time among samples from hospitalized individuals compared to samples from non-hospitalized participants (p = 0.001). CONCLUSION: This study has revealed higher titers and a higher probability of the persistence of IgG-S1 in severe cases after SARs-CoV-2 primary infection in unvaccinated recovered patients. Thus, in this study, the severe clinical presentation of COVID-19 was the main factor influencing serum levels and the persistence of IgG-S1 antibodies in COVID-19.

Animal models and SARS-CoV-2-induced pulmonary and neurological injuries.

Laboratory animals are essential mainly for experiments aiming to study pathogenesis and evaluate antivirals and vaccines against emerging human infectious diseases. Preclinical studies of coronavirus disease 19 (COVID-19) pathogenesis have used several animal species as models: transgenic human ACE2 mice (K18 mice), inbred BALB/c or C57BL/6N mice, ferrets, minks, domestic cats and dogs, hamsters, and macaques. However, the choice of an animal model relies on several limitations. Besides the host susceptibility, the researcher's experience with animal model management and the correct interpretation of clinical and laboratory records are crucial to succeed in preclinical translational research. Here, we summarise pathological and clinical findings correlated with virological data and immunological changes observed from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) experimental infections using different well-established SARS-CoV-2 animal model species. This essay aims to critically evaluate the current state of animal model translation to clinical data, as described in the human SARS-CoV-2 infection.

Levels and sources of hydrocarbons in the Patos Lagoon estuary and Cassino Beach mud bank (South Atlantic, Brazil): evidence of transference between environments.

This study assessed the concentrations and sources of natural and anthropogenic aliphatic (AHs) and polycyclic aromatic hydrocarbons (PAHs) in superficial sediments collected along the Patos Lagoon estuary and in sediment cores obtained from the Cassino Beach mud bank. Levels and distribution of n-alkanes indicate terrestrial sources, overlapping with a low amount of petrogenic hydrocarbons (heavy oils). Unresolved complex mixture (UCM) was observed in all samples. On the other hand, the distribution of PAHs in the sediments showed a predominance of pyrolytic over petrogenic sources. In general, hydrocarbons (HCs) contamination in the Patos Lagoon estuary and its adjacent coastal area can be considered low, except for sites near urban or industrial effluents, where moderate to high levels of contamination were found. Concentrations of hydrocarbons were homogeneous throughout the sediment cores, suggesting that mixing processes may have occurred along the layers or that HCs inputs to the mud banks were uniform during the studied deposition period. In addition, the levels and profile of HCs in the coastal sediments were similar to those observed in the estuary. Moreover, the frequent remobilization of sediments from the mud bank towards Cassino beach does not seem to pose any threats to the local biota or beach users since the levels of contamination were relatively low and below the threshold limits of sediment quality guidelines.

Inspiratory muscle training in addition to whole body vibration for functional and physical outcomes in pre-frail older women: a randomized controlled trial.

BACKGROUND: to investigate the efficacy of addition of inspiratory muscle training (IMT) to the whole body vibration (WBV) on functional outcomes, physical performance, muscle strength and metabolism in pre-frail older women. METHODS: this study was a randomized double-blind trial. Forty-two older women aged 60-80 years who meet the Cardiovascular Health Study frailty criteria for pre-frailty were randomly allocated to IMT + WBV, IMTsham + WBV or Sham groups. IMT + WBV group received 12 weeks of both trainings, whereas IMTsham + WVB received 12 weeks of WBV alone. Sham group received 12 weeks of IMT with a low fixed load and were positioned at the vibratory platform without therapeutic effect. Participants were evaluated before and after the intervention for the following outcomes: 6-min walk test distance (6MWD), balance using Tinetti test, functional mobility using timed up and go test (TUG), handgrip strength (HGS) and peripheral muscle metabolism (glucose and lactate levels). RESULTS: after the training, both groups IMT + WBV and IMTsham + WBV improved 6MWD [mean percentage changes = 20.31 (SD = 14.62) and 13.02 (SD = 12.14), respectively] compared with Sham [0.27 (SD = 6.51)], P <0.01. There was also a significant decrease of mean percentage changes on time of the TUG for IMT + WBV [-21.87 (SD = 7.87)] and IMTsham + WBV [-11.15 (SD = 13.64)] compared with Sham [-4.25 (SD = 13.25)], P <0.01. IMT + WBV group improved balance when compared with IMTsham + WBV and Sham groups (P <0.05 and < 0.01, respectively). HGS and levels of lactate and glucose were similar between groups. CONCLUSIONS: the addition of IMT to the WBV was effective to improve functionality, balance and physical performance in pre-frail older women.

Safety and immunogenicity of 17DD attenuated yellow fever vaccine in howler monkeys (Alouatta spp.).

BACKGROUND: Alouatta spp. are highly susceptible to yellow fever (YF) infection and develop an often fatal disease. The threat posed by an outbreak started in 2016 leads us to investigate vaccination as a potential tool in preventing YF in non-human primates (NHP). METHODS: Susceptible howler monkeys were immunized with three different concentrations of the human Brazilian commercial YF17DD vaccine. Post-vaccination viremia/RNAemia, immunogenicity, and safety were characterized. RESULTS: The vaccine did not produce YF clinical manifestations in any of the NHPs. After immunization, all animals seroconverted demonstrating the ability of the YF vaccine to induce humoral response in Alouatta species. CONCLUSIONS: The present work has demonstrated the safe and immunogenic profile of the existing YF 17DD vaccine in howler monkeys. This knowledge may support further studies with other susceptible monkey species and provide a possible solution for controlling epizootics and preventing the devastation of endangered species.

Prevention of Umbilical Sagging After Medium Definition Liposuction.

BACKGROUND: The loss of the umbilical vertical axis, causing a horizontal shape deformity after liposuction, is a current aesthetic issue. The use of energy devices, such as LASER and VASER, has been advocated as an option for improving skin retraction, but no data are available on the prevention of umbilical sagging. OBJECTIVES: The authors sought to describe a technique for preventing umbilical deformities after medium definition liposuction employing suction-assisted liposuction. METHODS: Over a period of 31 months, 62 patients underwent medium definition liposuction with direct needle fixation of the umbilical stalk to prevent horizontal umbilical deformities. All patients underwent surgery performed by a single surgeon (G.B.). All patients underwent objective measurements of the umbilical shape before and after the procedure utilizing digital image measurements by Mirror Image software, version 6.0 (Fairfield, NJ). Statistical analysis was performed with IBM SPSS Statistics V26. The mean age of the patients was 28.8 years. The follow-up evaluation was performed 2 weeks and 9 months postoperatively. RESULTS: Over a period of 31 months, 60 patients (96.7%) who underwent abdominal etching liposuction showed maintenance of (n = 9, 14.5%) or improvements in the umbilical shape 9 months postoperatively (n = 51, 82.2%, P < 0.05). Two patients (3.2%) experienced worsening of the umbilical shape after surgery despite suture fixation. CONCLUSIONS: Horizontal shape deformities of the umbilicus after liposuction can be improved by utilizing direct needle fixation of the umbilical stalk. The approach has been shown to be effective, safe, and reproducible for the prevention of umbilical sagging in selected patients.

HIV-1 subtype frequency in Northeast Brazil: A systematic review and meta-analysis.

Information on human immunodeficiency virus (HIV) molecular epidemiology is required to verify HIV/AIDS (acquired immune deficiency syndrome) epidemic dynamics in different regions, as well as provide support for response to antiretroviral therapy, transmission of resistance mutations, disease progression, and viral spread. The aim of this study was to conduct a systematic review and meta-analysis of the frequency of HIV-1 subtypes in Northeast Brazil. Seventy-six articles that refer to HIV-1 and its subtypes in the Northeast Brazil and published between 1 January 1999 and 31 August 2019 were identified. We included 27 articles for the qualitative synthesis, thus analyzing results from 4466 patients and 4298 genomic sequences. The results showed that subtypes B, F, and C and recombinant BF were responsible for 76% (IC95%: 71-80), 8% (IC95%: 5-11), 2% (IC95%: 2-3), and 7% (IC95%: 4-12) infections, respectively. The highest proportion of subtype B infections (82.2%) was observed in Piauí, while the subtype F had a high frequency in Pernambuco (23.4%). Bahia presented 11.6% of the proportion of recombinant BF. In addition, several recombinants such as AG, BC, BCF, and BD have been identified in the region. This is the first systematic review and meta-analysis on the HIV-1 subtype distribution in Northeast Brazil and has shown a high circulating viral diversity. Although subtype B is predominant in Brazil, a large frequency of non-B subtypes has also been found, which may have consequences for response to antiretroviral therapy, disease progression, and transmission. Thus, HIV molecular epidemiological data are essential for epidemic prevention and control strategies.

Initial development of biosimilar immune checkpoint blockers using HEK293 cells.

Antibodies that block interaction of immune checkpoint receptors with its ligands have revolutionized the treatment of several cancers. Despite the success of this approach, the high cost has been restricted the use of this class of drugs. In this context, the development of biosimilar can be an important strategy for reducing prices and expanding access after patent has been dropped. Here, we evaluated the use of HEK293 cells for transient expression of an immune checkpoint-blocking antibody as a first step for biosimilar development. Antibody light and heavy chain genes were cloned into pCI-neo vector and transiently expressed in HEK293 cells. The culture supernatant was then subjected to protein A affinity chromatography, which allowed to obtain the antibody with high homogeneity. For physicochemical comparability, biosimilar antibody and reference drug were analyzed by SDS-PAGE, isoelectric focusing, circular dichroism and fluorescence spectroscopy. The results indicated that the both antibodies have a high degree of structural similarity. Lastly, the biosimilar antibody binding capacity to target receptor was shown to be similar to reference product in ELISA and flow cytometry assays. These data demonstrate that the HEK293 system can be used as an important tool for candidate selection and early development of biosimilar antibodies.

Signaling via the MyD88 adaptor protein in B cells suppresses protective immunity during Salmonella typhimurium infection.

The myeloid differentiation primary response gene 88 (Myd88) is critical for protection against pathogens. However, we demonstrate here that MyD88 expression in B cells inhibits resistance of mice to Salmonella typhimurium infection. Selective deficiency of Myd88 in B cells improved control of bacterial replication and prolonged survival of the infected mice. The B cell-mediated suppressive pathway was even more striking after secondary challenge. Upon vaccination, mice lacking Myd88 in B cells became completely resistant against this otherwise lethal infection, whereas control mice were only partially protected. Analysis of immune defenses revealed that MyD88 signaling in B cells suppressed three crucial arms of protective immunity: neutrophils, natural killer cells, and inflammatory T cells. We further show that interleukin-10 is an essential mediator of these inhibitory functions of B cells. Collectively, our data identify a role for MyD88 and B cells in regulation of cellular mechanisms of protective immunity during infection.

Transcriptional analysis of flagellar and putative virulence genes of Arcobacter butzleri as an endocytobiont of Acanthamoeba castellanii.

Arcobacter butzleri is an emerging foodborne zoonotic pathogen that has been isolated from environmental water sources. This pathogen establishes in vitro endosymbiotic relationships with Acanthamoeba castellanii, a free-living amoeba found in environmental matrices such as soil and water. The principal aim of this study was to analyse the transcriptional pattern of flagellar (flaA-flaB-flgH-motA) and other putative virulence genes (ciaB-cadF-mviN-pldA) of A. butzleri during its interaction with A. castellanii by quantitative real-time PCR. The transcriptional analysis showed up-regulation of all genes analysed before A. butzleri became established as an endocytobiont of A. castellanii. In contrast, while A. butzleri remains an endocytobiont, a significant and sustained decrease in the transcription of all analysed genes was observed. Our findings suggest that A. butzleri requires a biphasic transcriptional pattern of flagellar and other putative virulence genes to establish an endosymbiotic relationship with A. castellanii.

Simultaneous colonization by Escherichia coli and Klebsiella pneumoniae harboring mcr-1 in Brazil.

CASE PRESENTATION: We present a case report of a woman, concurrently colonized by polymyxin-resistant E. coli and K. pneumoniae. A Brazilian female patient, in her mid-fifties, was hospitalized with schistosomiasis. During hospitalization, polymyxin-resistant E. coli and K. pneumoniae were isolated from surveillance cultures. METHODS: Identification, antimicrobial susceptibility testings, PCR for mcr-1, plasmid transfer by conjugation and whole genome sequencing were performed. RESULTS: E. coli ST744 and K. pneumoniae ST101 carrying mcr-1 gene were described. Transconjugant E. coli was positive for mcr-1 and IncX4 by PCR. The plasmid is a 33,304-base pair plasmid, and the mcr-1 gene was the only antimicrobial resistance gene present in the plasmid. CONCLUSIONS: This study presents a case report of a hospitalized woman, concurrently colonized by mcr-1-harboring E. coli ST744, a different ST from previously described in Brazil, and a K. pneumoniae ST101.

A Molybdenum Trioxide Hybrid Decorated by 3-(1,2,4-Triazol-4-yl)adamantane-1-carboxylic Acid: A Promising Reaction-Induced Self-Separating (RISS) Catalyst.

3-(1,2,4-Triazol-4-yl)adamantane-1-carboxylic acid (tradcH), a heterobifunctional organic ligand in which carboxylic acid and 1,2,4-triazole groups are united through a rigid 1,3-adamantanediyl spacer, was employed for the synthesis of a MoVI oxide organic hybrid. The ligand crystallized from water as tradcH·H2O (1), possessing a two-dimensional hydrogen-bonding network, and from ethanol as a cyclic molecular solvate with the composition (tradcH)3·2EtOH (2). Treatment of tradcH with MoO3 under hydrothermal conditions afforded a new Mo trioxide hybrid, [MoO3(tradcH)]·H2O (3), which was structurally characterized. In 3, the molybdenum atoms form a polymeric zigzag chain of {µ2-O-MoO2}n which is supported by double triazole bridges, while the carboxylic acid termini are left uncoordinated. The coordination environment of the Mo centers appears as distorted cis-{MoN2O4} octahedra. The hybrid exhibits high thermal stability (up to 270 °C) and was employed for a relatively broad scope of catalytic oxidation reactions in the liquid phase. Its catalytic behavior may be compared to a reversible mutation, featuring the best sides of homogeneous and heterogeneous catalysis. The original solid material converts into soluble active species, and the latter revert to the original material upon completion of the catalytic reaction, precipitating and allowing straightforward catalyst separation/reuse (like a heterogeneous catalyst). This catalyst was explored for a chemical reaction scope covering sulfoxidation, oxidative alcohol dehydrogenation, aldehyde oxidation, and olefin epoxidation, using hydrogen peroxide as an eco-friendly oxidant that gives water as a coproduct.

A Comparative Study of Molybdenum Carbonyl and Oxomolybdenum Derivatives Bearing 1,2,3-Triazole or 1,2,4-Triazoles in Catalytic Olefin Epoxidation.

The molybdenum(0)-carbonyl-triazole complexes [Mo(CO)3(L)3] [L = 1,2,3-triazole (1,2,3-trz) or 1,2,4-triazole (1,2,4-trz)] have been prepared and examined as precursors to molybdenum(VI) oxide catalysts for the epoxidation of cis-cyclooctene. Reaction of the carbonyl complexes with the oxidant tert-butyl hydroperoxide (TBHP) (either separately or in situ) gives oxomolybdenum(VI) hybrid materials that are proposed to possess one-dimensional polymeric structures in which adjacent oxo-bridged dioxomolybdenum(VI) moieties are further linked by bidentate bridging triazole (trz) ligands. A pronounced ligand influence on catalytic performance was found and the best result (quantitative epoxide yield within 1 h at 70 °C) was obtained with the 1,2,3-triazole oxomolybdenum(VI) hybrid. Both molybdenum oxide-triazole compounds displayed superior catalytic performance in comparison with the known hybrid materials [MoO3(trz)0.5], which have different structures based on organic-inorganic perovskite-like layers. With aqueous H2O2 as the oxidant instead of TBHP, all compounds were completely soluble and active. A pronounced ligand influence on catalytic performance was only found for the hybrids [MoO3(trz)0.5], and only the 1,2,4-trz compound displayed reaction-induced self-precipitation behavior. An insight into the type of solution species that may be involved in the catalytic processes with these compounds was obtained by separately treating [MoO3(1,2,4-trz)0.5] with excess H2O2, which led to the crystallization of the complex (NH4)1.8(H3O)0.2[Mo2O2(µ2-O)(O2)4(1,2,4-trz)]·H2O. The single-crystal X-ray investigation of this complex reveals an oxo-bridged dinuclear structure with oxodiperoxo groups being further linked by a single triazole bridge.

Triazolyl, Imidazolyl, and Carboxylic Acid Moieties in the Design of Molybdenum Trioxide Hybrids: Photophysical and Catalytic Behavior.

Three organic ligands bearing 1,2,4-triazolyl donor moieties, (S)-4-(1-phenylpropyl)-1,2,4-triazole (trethbz), 4-(1,2,4-triazol-4-yl)benzoic acid (trPhCO2H), and 3-(1H-imidazol-4-yl)-2-(1,2,4-triazol-4-yl)propionic acid (trhis), were prepared to evaluate their coordination behavior in the development of molybdenum(VI) oxide organic hybrids. Four compounds, [Mo2O6(trethbz)2]·H2O (1), [Mo4O12(trPhCO2H)2]·0.5H2O (2a), [Mo4O12(trPhCO2H)2]·H2O (2b), and [Mo8O25(trhis)2(trhisH)2]·2H2O (3), were synthesized and characterized. The monofunctional tr-ligand resulted in the formation of a zigzag chain [Mo2O6(trethbz)2] built up from cis-{MoO4N2} octahedra united through common µ2-O vertices. Employing the heterodonor ligand with tr/-CO2H functions afforded either layer or ribbon structures of corner- or edge-sharing {MoO5N} polyhedra (2a or 2b) stapled by tr-links in axial positions, whereas -CO2H groups remained uncoordinated. The presence of the im-heterocycle as an extra function in trhis facilitated formation of zwitterionic molecules with a protonated imidazolium group (imH+) and a negatively charged -CO2- group, whereas the tr-fragment was left neutral. Under the acidic hydrothermal conditions used, the organic ligand binds to molybdenum atoms either through [N-N]-tr or through both [N-N]-tr and µ2-CO2- units, which occur in protonated bidentate or zwitterionic tetradentate forms (trhisH+ and trhis, respectively). This leads to a new zigzag subtopological motif (3) of negatively charged polyoxomolybdate {Mo8O25}n2n- consisting of corner- and edge-sharing cis-{MoO4N2} and {MoO6} octahedra, while the tetradentate zwitterrionic trhis species connect these chains into a 2D net. Electronic spectra of the compounds showed optical gaps consistent with semiconducting behavior. The compounds were investigated as epoxidation catalysts via the model reactions of achiral and prochiral olefins (cis-cyclooctene and trans-ß-methylstyrene) with tert-butylhydroperoxide. The best-performing catalyst (1) was explored for the epoxidation of other olefins, including biomass-derived methyl oleate, methyl linoleate, and prochiral dl-limonene.

Synthesis and Structural Elucidation of Triazolylmolybdenum(VI) Oxide Hybrids and Their Behavior as Oxidation Catalysts.

A large family of bifunctional 1,2,4-triazole molecular tectons (tr) has been explored for engineering molybdenum(VI) oxide hybrid solids. Specifically, tr ligands bearing auxiliary basic or acidic groups were of the type amine, pyrazole, 1H-tetrazole, and 1,2,4-triazole. The organically templated molybdenum(VI) oxide solids with the general compositions [MoO3(tr)], [Mo2O6(tr)], and [Mo2O6(tr)(H2O)2] were prepared under mild hydrothermal conditions or by refluxing in water. Their crystal structures consist of zigzag chains, ribbons, or helixes of alternating cis-{MoO4N2} or {MoO5N} polyhedra stapled by short [N-N]-tr bridges that for bitriazole ligands convert the motifs into 2D or 3D frameworks. The high thermal (235-350 °C) and chemical stability observed for the materials makes them promising for catalytic applications. The molybdenum(VI) oxide hybrids were successfully explored as versatile oxidation catalysts with tert-butyl hydroperoxide (TBHP) or aqueous H2O2 as an oxygen source, at 70 °C. Catalytic performances were influenced by the different acidic-basic properties and steric hindrances of coordinating organic ligands as well as the structural dimensionality of the hybrid.

Synthesis, structural elucidation, and catalytic properties in olefin epoxidation of the polymeric hybrid material [Mo3O9(2-[3(5)-pyrazolyl]pyridine)]n.

The reaction of [MoO2Cl2(pzpy)] (1) (pzpy = 2-[3(5)-pyrazolyl]pyridine) with water in an open reflux system (16 h), in a microwave synthesis system (120 °C, 2 h), or in a Teflon-lined stainless steel digestion bomb (100 °C, 19 h) gave the molybdenum oxide/pyrazolylpyridine polymeric hybrid material [Mo3O9(pzpy)]n (2) as a microcrystalline powder in yields of 72­79%. Compound 2 can also be obtained by the hydrothermal reaction of MoO3, pzpy, and H2O at 160 °C for 3 d. Secondary products isolated from the reaction solutions included the salt (pzpyH)2(MoCl4) (3) (pzpyH = 2-[3(5)-pyrazolyl]pyridinium), containing a very rare example of the tetrahedral MoCl4(2­) anion, and the tetranuclear compound [Mo4O12(pzpy)4] (4). Reaction of 2 with excess tert-butylhydroperoxide (TBHP) led to the isolation of the oxodiperoxo complex [MoO(O2)2(pzpy)] (5). Single-crystal X-ray structures of 3 and 5 are described. Fourier transform (FT)-IR and FT Raman spectra for 1, 4, and 5 were assigned based on density functional theory calculations. The structure of 2 was determined from synchrotron powder X-ray diffraction data in combination with other physicochemical information. In 2, a hybrid organic­inorganic one-dimensional (1D) polymer, ∞(1)[Mo3O9(pzpy)], is formed by the connection of two very distinct components: a double ladder-type inorganic core reminiscent of the crystal structure of MoO3 and 1D chains of corner-sharing distorted {MoO4N2} octahedra. Compound 2 exhibits moderate activity and high selectivity when used as a (pre)catalyst for the epoxidation of cis-cyclooctene with TBHP. Under the reaction conditions used, 2 is poorly soluble and is gradually converted into 5, which is at least partly responsible for the catalytic reaction.

Triazolyl-based copper-molybdate hybrids: from composition space diagram to magnetism and catalytic performance.

The multicomponent mixed-metal Cu(II)/Mo(VI) oxides/1,3-bis(1,2,4-triazol-4-yl)adamantane (tr2ad) system was thoroughly studied employing a compositional diagram approach. The concept allowed us to prepare three layered copper-molybdate hybrid solids [Cu(II)2(tr2ad)4](Mo8O26) (1), [Cu4(II)(µ4-O)(tr2ad)2(MoO4)3]·7.5H2O (2), and [Cu(I)2(tr2ad)2](Mo2O7)·H2O (3), and to elucidate the relationship between initial reagent concentration/stoichiometry and the stability of the resultant structural motifs. Compounds 1 and 2 were found to dominate throughout a wide crystallization range of the concentration triangle, whereas compound 3 was formed by redox processes in the narrow crystallization area having a high excess of Cu(OAc)2·H2O. Independent experiments carried out with Cu(OAc)2 and (NH4)6Mo7O24 in the absence of tr2ad, under the same conditions, revealed the formation of low-valent and bimetallic oxides, including Cu2O, MoO2, Cu(Mo3O10)·H2O, and Cu3(MoO4)2(OH)2. Compounds 1 and 2 show high thermal and chemical stability as examined as catalysts in the epoxidation of cis-cyclooctene and the oxidation of benzyl alcohol (BzOH) with different types of oxidants. The oxidation reaction of BzOH using tert-butyl hydroperoxide (TBHP) as the oxidant, in the presence of 1 or 2, led to benzaldehyde and benzoic acid (PhCO2H), with the latter being formed in up to 90% yield at 24 h. The results suggest that 1 and 2 may be favorable heterogeneous catalysts for the synthesis of PhCO2H. Whereas compound 1 only reveals a weak ferromagnetic coupling between neighboring Cu(II) centers (J = 0.41 cm(-1)), compound 2 shows distinct intracluster antiferromagnetic exchange interactions (J = -29.9 cm(-1), J' = -25.7 cm(-1)), which consequently results in a diamagnetic ground state.

Effect of cryoprotectants on the survival of cascudo preto (Rhinelepis aspera) embryos stored at -8 °C.

Cryopreservation of germplasm provides a promising method to preserve fish genetic material, which is of great importance in preservation of species diversity, aquaculture, and management of fish models used in biomedical research. In the present study, cryopreservation of Rhinelepis aspera embryos, a Brazilian endangered species, was studied for the first time using a short-term cooling protocol. Embryos at blastoporous closing stage were selected, placed in 6-ml glass vials and stored at -8 °C for 6 h in 10 different cryoprotectant solutions: S1 (17.1% sucrose + 9% methanol); S2 (17.1% sucrose + 9% DMSO); S3 (8.5% sucrose + 8.5% glucose + 9% methanol); S4 (8.5% sucrose + 8.5% glucose + 9% DMSO); S5 (17.1% sucrose + 9% ethylene glycol); S6 (8.5% sucrose + 8.5% glucose + 9% ethylene glycol); S7 (17.1% sucrose + 4.5% methanol + 4.5% DMSO); S8 (17.1% sucrose + 4.5% methanol + 4.5% ethylene glycol); S9 (17.1% sucrose + 4.5% DMSO + 4.5% ethylene glycol); and S10 (100% water). Embryo viability was assessed by hatching rate, counting live larvae and number of failed eggs under a stereomicroscope. The results showed that only the cryoprotectant solutions that contained methanol associated to sucrose (S1, S7 and S8) provided partial protection of Rhinelepis aspera embryos from cold damage (over 50% hatching rate in S1), while the use of DMSO and ethylene glycol, isolated or in combination, resulted in no hatching rate. Further studies are needed in order to extend the storage time and to improve the hatching rate for the species.

Injuries in pacu embryos (Piaractus mesopotamicus) after freezing and thawing.

Although the sperm cryopreservation of freshwater and marine teleosts has been feasible for years, the cryopreservation of some fish embryos still remains elusive. Thus, the objective of this experiment was to analyze the embryo morphology after freezing and thawing 40 embryos of Piaractus mesopotamicus immersed into methanol and ethylene glycol, both at 7, 10 and 13% plus 0.1 M sucrose for 10 min. Soon after thawing, three embryos were treated with historesin, stained with hematoxylin-eosin and analyzed under an optical microscope. From every treatment, one palette containing embryos was thawed and incubated, but none of the eggs hatched. Samples containing two embryos were immersed into 10% methanol or 10% ethylene glycol both in association with sucrose, and embryos immersed into only water or sucrose solution were frozen, processed and analyzed using scanning electron microscopy (SEM). In both cases, the control group was immersed into only water. Although the embryos had the chorion, vitello, yolk syncytial layer and blastoderm, all of them were found altered under the optical microscope and by SEM. The chorion was irregular and injured; there was no individuality in the yolk granules; the yolk syncytial layer had an irregular shape, thickness and size; the blastoderm showed injuries in the nucleus shape and sometimes was absent; the blastoderm was located in atypical areas and absent in some embryos. In conclusion, no treatment was effective in preserving the embryos, and none of the embryos avoided injury from intracellular ice formation. These morphological injuries during the freezing process made the P. mesopotamicus embryos unfeasible for hatching.