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N6-methyladenosine (m6A) regulates mRNA metabolism. While it has been implicated in the development of the mammalian brain and in cognition, the role of m6A in synaptic plasticity, especially during cognitive decline, is not fully understood. In this study, we employed methylated RNA immunoprecipitation sequencing to obtain the m6A epitranscriptome of the hippocampal subregions CA1, CA3, and the dentate gyrus and the anterior cingulate cortex (ACC) in young and aged mice. We observed a decrease in m6A levels in aged animals. Comparative analysis of cingulate cortex (CC) brain tissue from cognitively intact human subjects and Alzheimer's disease (AD) patients showed decreased m6A RNA methylation in AD patients. m6A changes common to brains of aged mice and AD patients were found in transcripts linked to synaptic function including calcium/calmodulin-dependent protein kinase 2 (CAMKII) and AMPA-selective glutamate receptor 1 (Glua1). We used proximity ligation assays to show that reduced m6A levels result in decreased synaptic protein synthesis as exemplified by CAMKII and GLUA1. Moreover, reduced m6A levels impaired synaptic function. Our results suggest that m6A RNA methylation controls synaptic protein synthesis and may play a role in cognitive decline associated with aging and AD.
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Doença de Alzheimer , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina , Humanos , Camundongos , Animais , Idoso , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Hipocampo/metabolismo , Doença de Alzheimer/metabolismo , Envelhecimento/metabolismo , RNA/metabolismo , Mamíferos/genéticaRESUMO
BACKGROUND: Chromosomal abnormalities are present in 50 to 60% of miscarriages and in 6 to 19% of stillbirths. Although microarrays are preferred for studying chromosomal abnormalities, many hospitals cannot offer this methodology. OBJECTIVE: To present the results of the cytogenetic analysis of 303 products of conception (POC), which included 184 miscarriages, 49 stillbirths and 17 cases of undefined age. MATERIAL AND METHODS: Karyotyping, fluorescence in situ hybridization, short tandem repeats and microarrays were used, depending on the type of loss and available sample. RESULTS: In 29 POCs we found maternal tissue and were eliminated from the analyses. Informative results were obtained in 250 (91.2 %)/274 cases; the karyotyping success rate was 80.7%; that of single nucleotide polymorphism microarrays, 94.5%; and that of fluorescence in situ hybridization and short tandem repeat, 100%. Cytogenetic abnormalities were observed in 57.6% of miscarriages and in 24.5% of stillbirths; 94% of total anomalies were numerical and 6% were submicroscopic. CONCLUSIONS: Karyotyping with simultaneous short tandem repeat study to rule out contamination of maternal cells is effective for studying miscarriages; in stillbirths, microarrays are recommended.
ANTECEDENTES: Las alteraciones cromosómicas están presentes en 50 a 60 % de los abortos espontáneos y en 6 a 19 % de los mortinatos. Aunque se prefieren los microarreglos para estudiarlos, numerosos hospitales no pueden ofrecerlos. OBJETIVO: Presentar los resultados del estudio citogenético de 303 productos de la concepción (POC), 184 se obtuvieron de abortos espontáneos, 49 fueron mortinatos y en 17 no se identificó la de edad gestacional. MATERIAL Y MÉTODOS: Se empleó cariotipo, hibridación in situ con fluorescencia, secuencias cortas repetidas en tándem y microarreglos, según el tipo de pérdida y la muestra disponible. RESULTADOS: En 29 POC se encontró tejido materno, por lo que fueron eliminados de los análisis. En 250 (91.2 %)/274 casos se obtuvieron resultados informativos; la tasa de éxito del cariotipo fue de 80.7 %; la de los microarreglos de SNP, de 94.5 %; y la de la hibridación fluorescente in situ y la repetición corta en tándem, de 100 %. Se observaron anomalías citogenéticas en 57.6 % de los abortos espontáneos y en 24.5 % de los mortinatos; 94 % de las anomalías fueron numéricas y 6 %, submicroscópicas. CONCLUSIONES: El cariotipo en conjunto con el estudio de secuencias cortas repetidas en tándem para descartar contaminación de células maternas es efectivo para estudiar abortos espontáneos; los microarreglos se recomiendan en los mortinatos.
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Aborto Espontâneo , Aberrações Cromossômicas , Hibridização in Situ Fluorescente , Cariotipagem , Humanos , Feminino , Aborto Espontâneo/epidemiologia , Aborto Espontâneo/genética , México/epidemiologia , Gravidez , Cariotipagem/métodos , Natimorto/genética , Natimorto/epidemiologia , Adulto , Análise Citogenética/métodos , Repetições de Microssatélites , Polimorfismo de Nucleotídeo Único , Adulto JovemRESUMO
Terpenes and terpenoids are a group of isoprene-derived molecules that constitute the largest group of natural products and secondary metabolites produced by living things, with more than 25,000 compounds reported. These compounds are synthesized by enzymes called terpene synthases, which include several families of cyclases and enzymes. These are responsible for adding functional groups to cyclized structures. Fungal terpenoids are of great interest for their pharmacological properties; therefore, understanding the mechanisms that regulate their synthesis (regulation of the mevalonate pathway, regulation of gene expression, and availability of cofactors) is essential to direct their production. For this reason, this review addresses the detailed study of the biosynthesis of fungal terpenoids and their regulation by various physiological and environmental factors.
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Alquil e Aril Transferases , Proteínas Fúngicas , Fungos , Terpenos , Terpenos/metabolismo , Fungos/enzimologia , Alquil e Aril Transferases/metabolismo , Proteínas Fúngicas/metabolismoRESUMO
This paper presents so-called thermoelectric generators (TEGs), which are considered thermal engines that transform heat into electricity using the Seebeck effect for this purpose. By using linear irreversible thermodynamics (LIT), it is possible to study the thermodynamic properties of TEGs for three different operating regimes: maximum power output (MPO), maximum ecological function (MEF) and maximum power efficiency (MPE). Then, by considering thermoelectricty, using the correspondence between the heat capacity of a solid and the metabolic rate, and taking the generation of energy by means of the metabolism of an organism as a process out of equilibrium, it is plausible to use linear irreversible thermodynamics (LIT) to obtain some interesting results in order to understand how metabolism is generated by a particle's released energy, which explains the empirically studied allometric laws.
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ABSTRACT: Musculoskeletal injuries are common in American football, with an incidence ranging from approximately 10 to 35 per 1000 playing hours. Injuries occur more commonly in games than in practice. Although several studies have analyzed specific injury types in football, this review aims to describe the most common knee injuries sustained by American football players and to review the existing literature pertaining to the radiologic findings used in the diagnosis of these injuries.
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Futebol Americano , Traumatismos do Joelho , Futebol Americano/lesões , Humanos , Incidência , Traumatismos do Joelho/diagnóstico por imagemRESUMO
Eggplant (Solanum melongena L.) is an important vegetable cultivated in Mexico and the state of Sinaloa is the largest producer of eggplants with 90% of the country's total production. In April 2022, eggplants cv. Barcelona exhibiting root-knot, stunted growth, and yellowing were detected in a greenhouse in Culiacán, Sinaloa, Mexico. Disease incidence was approximately 10% (1000 plants evaluated). Ten soil samples were collected from the greenhouse. An average of 400 root-knot nematode second-stage juveniles (J2s) were extracted from 100 g of soil for each sample. Roots were washed with tap water and dissected. Females and egg masses were obtained by dissecting galls. Microscopic examination of the perineal pattern of mature females (n= 10) was round to ovoid, with rounded and high dorsal arch. Females (n= 20) were globular to pear-shaped, body length of 645 to 739 µm, body width of 470 to 559 µm; the stylet was dorsally curved, 15.1 to 16.2 µm long, and with rounded stylet knobs; neck length of 195 to 202 µm and the distance from the base of the stylet to the dorsal gland orifice (DGO) was 4.2 to 5.8 µm. Second-stage juveniles were vermiform, annulated, and tapering at both ends. Morphological characteristics of the females and J2s were consistent with those reported for Meloidogyne enterolobii (Yang and Eisenback 1983). For molecular identification, total DNA was extracted from individual females according to the extraction protocol described by Hu et al. (2011), and the ribosomal intergenic spacer 2 (IGS2) was amplified by PCR using the specific primers Me-F/Me-R for M. enterolobii (Long et al. 2006). PCR amplification generated a 236-bp fragment for the analyzed sample and the amplicon was sequenced. The sequence was deposited in GenBank under the accession number OP004802. BLASTn searches showed 100% identity with available sequences of M. enterolobii from the USA (MH800967) and China (KP411228, MT742011). A phylogenetic tree including published IGS2 sequences for Meloidogyne spp. was constructed based on Maximum Likelihood method. The phylogenetic analysis placed the sequence MeCUB in the same clade with Meloidogyne enterolobii. Pathogenicity tests were performed under greenhouse conditions by inoculating 5000 eggs of a pure population of M. enterolobii on 10 healthy eggplants cv. Barcelona (30-day-old) grown in pots with sterilized soil. Five uninoculated eggplants were used as control. Plants were maintained at 26 to 34°C in a greenhouse for 35 days. Stunted growth and root-galling symptoms appeared on inoculated plants after 21 days, whereas control plants remained symptomless. Nematode reproduction factor (final population density/initial population density) was 0.93 and 2.28 at 28 and 35 days after inoculation, respectively. The nematode on the inoculated roots was morphologically identical to that observed on naturally infected roots in the field. The pathogenicity test was carried out twice with similar results. Meloidogyne enterolobii has been previously reported on eggplants in Puerto Rico (Rammah and Hirschmann 1988). To our knowledge, this is the first report of M. enterolobii causing root-knot of eggplant in Mexico. This nematode is widely distributed in Sinaloa affecting other vegetable crops such as tomato (Martínez-Gallardo et al. 2015), chili (Carrillo-Fasio et al. 2020), and cucumber (Gómez-González et al. 2020), so future studies are required to evaluate integrated management strategies.
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In this paper, we show an analysis of the global stability of a Curzon-Ahlborn engine considering that the working substance of the engine satisfies the Van der Waals equation of state, which is more general than the ideal gas case. We use the Lyapunov stability theory for the case where the engine operates at a maximum power output. We analyze the steady state of the intermediate temperatures as well as the asymptotic behavior of the performance of the engine. Additionally, we study the relationship between the inherent time delay by analyzing the dynamic properties of the system and the stability of the steady state. We present illustrative graphs of the obtained results. Finally, we include a brief discussion of the obtained results and appropriate conclusions.
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SARS-CoV-2 is a novel ß-coronavirus that caused the COVID-19 pandemic disease, which spread rapidly, infecting more than 134 million people, and killing almost 2.9 million thus far. Based on the urgent need for therapeutic and prophylactic strategies, the identification and characterization of antibodies has been accelerated, since they have been fundamental in treating other viral diseases. Here, we summarized in an integrative manner the present understanding of the immune response and physiopathology caused by SARS-CoV-2, including the activation of the humoral immune response in SARS-CoV-2 infection and therefore, the synthesis of antibodies. Furthermore, we also discussed about the antibodies that can be generated in COVID-19 convalescent sera and their associated clinical studies, including a detailed characterization of a variety of human antibodies and identification of antibodies from other sources, which have powerful neutralizing capacities. Accordingly, the development of effective treatments to mitigate COVID-19 is expected. Finally, we reviewed the challenges faced in producing potential therapeutic antibodies and nanobodies by cell factories at an industrial level while ensuring their quality, efficacy, and safety.
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Anticorpos Antivirais/uso terapêutico , Tratamento Farmacológico da COVID-19 , Anticorpos Monoclonais/biossíntese , Anticorpos Monoclonais/química , Anticorpos Monoclonais/uso terapêutico , Anticorpos Neutralizantes/química , Anticorpos Neutralizantes/uso terapêutico , Anticorpos Antivirais/sangue , COVID-19/imunologia , COVID-19/virologia , Humanos , Imunidade Humoral , Imunidade Inata , Imunoglobulinas/química , Imunoglobulinas/uso terapêutico , SARS-CoV-2/imunologia , SARS-CoV-2/isolamento & purificação , Anticorpos de Cadeia Única/química , Anticorpos de Cadeia Única/uso terapêuticoRESUMO
BACKGROUND: The Institute of Medicine reported that more than 1.5 million preventable adverse drug events occur annually in the United States. Comprehensive Medication Management (CMM) is the medication review process to improve clinical outcomes, enhance patient adherence, reduce drug therapy problems and reduce health care costs. University of Texas (UT) Physicians implemented a CMM program in several community-based clinics. We evaluated the effectiveness of CMM to reduce drug therapy problems and achieve medical cost savings. METHODS: This was a retrospective, observational study of CMM participants from October 2015 to September 2016. Program participants included patients aged 18 years or older who had taken more than 4 prescribed medications and were diagnosed with at least one of the following chronic diseases: hypertension, congestive heart failure, chronic obstructive pulmonary disease, asthma or diabetes. Under the CMM program, a clinical pharmacist reviewed patients' electronic health records and created action plans to resolve identified drug problems. As part of the evaluation of the clinical process, two independent physicians conducted peer review on the recommendations issued by the pharmacist in order to establish inter-rater reliability of drug therapy problems and potential consequent medical services. The drug therapy problems were identified and classified into four categories: indication, effectiveness, safety and/or compliance. The average cost of avoided medical services was obtained based on cost extrapolations from the literature, combined with hospital discharge data. Potential medical services avoided were linked to the average cost of those services to calculate the total cost savings of the program from the payers' perspective. RESULTS: By reviewing electronic health records of 3280 patients, the pharmacist identified 301 drug therapy problems and resolved 49.8% of these problems with collaboration from the patient's primary care physician or care team. The most commonly identified drug problems were related to potentially adverse drug reactions or inappropriate drug dosage. The CMM program resulted in potential cost savings of $1,143,015. CONCLUSIONS: The CMM program resolved medication therapy problems among program participants and achieved significant health care cost savings.
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Doença Crônica/tratamento farmacológico , Conduta do Tratamento Medicamentoso/organização & administração , Atenção Primária à Saúde/organização & administração , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Reforma dos Serviços de Saúde , Pesquisa sobre Serviços de Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Avaliação de Programas e Projetos de Saúde , Reembolso de Incentivo/organização & administração , Estudos Retrospectivos , Texas , Adulto JovemRESUMO
This work presents an analysis for real and synthetic angiogenic networks using a tomography image that obtains a portrait of a vascular network. After the image conversion into a binary format it is possible to measure various network properties, which includes the average path length, the clustering coefficient, the degree distribution and the fractal dimension. When comparing the observed properties with that produced by the Invasion Percolation algorithm (IPA), we observe that there exist differences between the properties obtained by the real and the synthetic networks produced by the IPA algorithm. Taking into account the former, a new algorithm which models the expansion of an angiogenic network through randomly heuristic rules is proposed. When comparing this new algorithm with the real networks it is observed that now both share some properties. Once creating synthetic networks, we prove the robustness of the network by subjecting the original angiogenic and the synthetic networks to the removal of the most connected nodes, and see to what extent the properties changed. Using this concept of robustness, in a very naive fashion it is possible to launch a hypothetical proposal for a therapeutic treatment based on the robustness of the network.
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OBJECTIVES: From a genetic perspective, relatively little is known about how mass emigrations of African, European, and Asian peoples beginning in the 16th century affected Indigenous Caribbean populations. Therefore, we explored the impact of serial colonization on the genetic variation of the first Caribbean islanders. MATERIALS AND METHODS: Sixty-four members of St. Vincent's Garifuna Community and 36 members of Trinidad's Santa Rosa First People's Community (FPC) of Arima were characterized for mitochondrial DNA and Y-chromosome diversity via direct sequencing and targeted SNP and STR genotyping. A subset of 32 Garifuna and 18 FPC participants were genotyped using the GenoChip 2.0 microarray. The resulting data were used to examine genetic diversity, admixture, and sex biased gene flow in the study communities. RESULTS: The Garifuna were most genetically comparable to African descendant populations, whereas the FPC were more similar to admixed American groups. Both communities also exhibited moderate frequencies of Indigenous American matrilines and patrilines. Autosomal SNP analysis indicated modest Indigenous American ancestry in these populations, while both showed varying degrees of African, European, South Asian, and East Asian ancestry, with patterns of sex-biased gene flow differing between the island communities. DISCUSSION: These patterns of genetic variation are consistent with historical records of migration, forced, or voluntary, and suggest that different migration events shaped the genetic make-up of each island community. This genomic study is the highest resolution analysis yet conducted with these communities, and provides a fuller understanding of the complex bio-histories of Indigenous Caribbean peoples in the Lesser Antilles.
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Grupos Raciais/genética , Grupos Raciais/história , Adulto , Cromossomos Humanos Y/genética , DNA/genética , DNA Mitocondrial/genética , Feminino , Genética Populacional , História do Século XV , História do Século XVI , História do Século XVIII , História do Século XIX , História Antiga , Migração Humana/história , Humanos , Masculino , São Vicente e Granadinas , Trinidad e TobagoRESUMO
INTRODUCTION: Erdheim-Chester disease is a rare, multisystem hematologic disease. Cardiovascular involvement is seen in patients with Erdheim-Chester disease and can lead to increased morbidity and mortality. In this series, we report various cardiovascular manifestations of patients with Erdheim-Chester disease. METHODS: This study includes patients with Erdheim-Chester disease who were referred to our institution from 12/3/2009 through 12/13/2017. All patients had biopsy-proven Erdheim-Chester disease. Clinical data, multimodality imaging, and cardiac tests were reviewed. RESULTS: Cardiovascular findings in 24 patients with Erdheim-Chester disease were included in the study. We reviewed available transthoracic echocardiograms, whole body PET/CT scans, and CMR studies. Most patients were male and mean age at the time of diagnosis was 58 years. Pericardial involvement (13%), myocardial infiltration (25%), endocardial involvement (4%), valvular disease (17%), aortic/vascular disease (17%), conduction system infiltration (8%), and coronary artery disease (25%) were present. At a median follow-up of 5.5 years, mortality was 17%. CONCLUSIONS: Erdheim-Chester disease can involve various cardiovascular structures and is frequently diagnosed on an imaging modality. Some patients had asymptomatic involvement, but others presented with ischemic heart disease, heart failure, valvular disease, and conduction system abnormalities. Early recognition of cardiovascular involvement of Erdheim-Chester disease is needed because of high morbidity and mortality.
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Diagnóstico por Imagem/métodos , Doença de Erdheim-Chester/complicações , Cardiopatias/complicações , Cardiopatias/diagnóstico por imagem , Adulto , Idoso , Ecocardiografia , Feminino , Seguimentos , Cardiopatias/fisiopatologia , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Imagem Multimodal/métodos , Tomografia por Emissão de Pósitrons combinada à Tomografia ComputadorizadaRESUMO
This paper presents a finite-time thermodynamic optimization based on three different optimization criteria: Maximum Power Output (MP), Maximum Efficient Power (MEP), and Maximum Power Density (MPD), for a simplified Curzon-Ahlborn engine that was first proposed by Agrawal. The results obtained for the MP are compared with those obtained using MEP and MPD criteria. The results show that when a Newton heat transfer law is used, the efficiency values of the engine working in the MP regime are lower than the efficiency values ( τ ) obtained with the MEP and MPD regimes for all values of the parameter τ = T 2 / T 1 , where T 1 and T 2 are the hot and cold temperatures of the engine reservoirs ( T 2 < T 1 ) , respectively. However, when a Dulong-Petit heat transfer law is used, the efficiency values of the engine working at MEP are larger than those obtained with the MP and the MPD regimes for all values of τ . Notably, when 0 < τ < 0.68 , the efficiency values for the MP regime are larger than those obtained with the MPD regime. Also, when 0.68 < τ < 1 , the efficiency values for the aforementioned regimes are similar. Importantly, the parameter τ plays a crucial role in the engine performance, providing guidance during the design of real power plants.
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Multi-block polymers are highly desirable for their addressable functions that are both unique and complementary among the blocks. With metal-containing polymers, the goal is even more challenging insofar as the metal properties may considerably extend the materials functions to sensing, catalysis, interaction with metal nanoparticles, and electro- or photochrome switching. Ring-opening metathesis polymerization (ROMP) has become available for the formation of living polymers using highly efficient initiators such as the 3rd generation Grubbs catalyst [RuCl2 (NHC)(=CHPh)(3-Br-C5 H4 N)2 ], 1. Among the 24 possibilities to introduce 4 blocks of metallopolymers into a tetrablock metallocopolymer by ROMP using the catalyst 1, two viable pathways are disclosed. The synthesis, characterization, electrochemistry, electron-transfer chemistry, and remarkable electrochromic properties of these new nanomaterials are presented.
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Substituted ferrocenes with various stereoelectronic effects including a ferrocene-terminated dendrimer in ether reduce aqueous HAuCl4 to gold nanoparticles (AuNPs) by interfacial electron transfer. The dependence on the stirring speed plays a crucial role, and the stereoelectronic influences on the reaction rates are dramatic. With a ferrocene-containing polymer, the reaction is conducted using an homogeneous THF/water medium, also forming AuNPs. Fully stable functional, dendritic and polymeric ferricinium chloride-stabilized AuNPs are obtained with core sizes between 13 and 35 nm, an optimal size range for potential biomedical applications. Finally the ferricinium coating of the Au nanoparticles is replaced by a more electron-rich ferricinium derivative by exergonic redox reaction with the corresponding ferrocene derivative.
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Bacterial meningitis and viral encephalitis, particularly herpes simplex encephalitis, are severe neurological infections that, if not treated promptly and effectively, lead to poor neurological outcome or death. Because of the value of early recognition and treatment, meningitis and encephalitis was chosen as an Emergency Neurological Life Support protocol. This protocol provides a practical approach to recognition and urgent treatment of bacterial meningitis and encephalitis. Appropriate imaging, spinal fluid analysis, and early empiric treatment are discussed. Though uncommon in its full form, the typical clinical triad of headache, fever, and neck stiffness should alert the clinical practitioner to the possibility of a central nervous system infection. Early attention to the airway and maintaining normotension are crucial steps in the treatment of these patients, as is rapid treatment with anti-infectives and, in some cases, corticosteroids.
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Protocolos Clínicos , Cuidados Críticos/métodos , Serviços Médicos de Emergência/métodos , Encefalite/diagnóstico , Encefalite/terapia , Cuidados para Prolongar a Vida/métodos , Meningite/diagnóstico , Meningite/terapia , Neurologia/métodos , Guias de Prática Clínica como Assunto , Protocolos Clínicos/normas , Cuidados Críticos/normas , Serviços Médicos de Emergência/normas , Encefalite/tratamento farmacológico , Humanos , Cuidados para Prolongar a Vida/normas , Meningite/tratamento farmacológico , Neurologia/normas , Guias de Prática Clínica como Assunto/normasRESUMO
UNLABELLED: Polyurethane (PU) is widely used in many aspects of modern life because of its versatility and resistance. However, PU waste disposal generates large problems, since it is slowly degraded, there are limited recycling processes, and its destruction may generate toxic compounds. In this work, we isolated fungal strains able to grow in mineral medium with a polyester PU (PS-PU; Impranil DLN) or a polyether PU (PE-PU; Poly Lack) varnish as the only carbon source. Of the eight best Impranil-degrading strains, the six best degraders belonged to the Cladosporium cladosporioides complex, including the species C. pseudocladosporioides, C. tenuissimum, C. asperulatum, and C. montecillanum, and the two others were identified as Aspergillus fumigatus and Penicillium chrysogenum The best Impranil degrader, C. pseudocladosporioides strain T1.PL.1, degraded up to 87% after 14 days of incubation. Fourier transform infrared (FTIR) spectroscopy analysis of Impranil degradation by this strain showed a loss of carbonyl groups (1,729 cm(-1)) and N-H bonds (1,540 and 1,261 cm(-1)), and gas chromatography-mass spectrometry (GC-MS) analysis showed a decrease in ester compounds and increase in alcohols and hexane diisocyanate, indicating the hydrolysis of ester and urethane bonds. Extracellular esterase and low urease, but not protease activities were detected at 7 and 14 days of culture in Impranil. The best eight Impranil-degrading fungi were also able to degrade solid foams of the highly recalcitrant PE-PU type to different extents, with the highest levels generating up to 65% of dry-weight losses not previously reported. Scanning electron microscopy (SEM) analysis of fungus-treated foams showed melted and thinner cell wall structures than the non-fungus-treated ones, demonstrating fungal biodegradative action on PE-PU. IMPORTANCE: Polyurethane waste disposal has become a serious problem. In this work, fungal strains able to efficiently degrade different types of polyurethanes are reported, and their biodegradative activity was studied by different experimental approaches. Varnish biodegradation analyses showed that fungi were able to break down the polymer in some of their precursors, offering the possibility that they may be recovered and used for new polyurethane synthesis. Also, the levels of degradation of solid polyether polyurethane foams reported in this work have never been observed previously. Isolation of efficient polyurethane-degrading microorganisms and delving into the mechanisms they used to degrade the polymer provide the basis for the development of biotechnological processes for polyurethane biodegradation and recycling.
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Fungos/isolamento & purificação , Fungos/metabolismo , Poliésteres/metabolismo , Poliuretanos/metabolismo , Biodegradação Ambiental , Fungos/classificação , Fungos/genética , Cromatografia Gasosa-Espectrometria de Massas , Pintura/análise , Pintura/microbiologia , Poliésteres/química , Poliuretanos/química , Microbiologia do SoloRESUMO
Ferrocene (Fc) in ether reduces HAuCl4 in water within seconds under ambient conditions in air upon stirring, forming ferricinium chloride stabilized water-soluble 20 nm gold nanoparticles (AuNPs) that are redispersible in the presence of poly(N-vinylmethylpyrrolidone) or NaBH4 + thiol. After reduction with NaBH4 yielding Fc and 26 nm sodium poly(hydroxyborate) stabilized AuNPs, the core size no longer changes following reactions with thiols providing (RS)nAuNPs.
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Diblock metallopolymer polyelectrolytes containing the two redox-robust cationic sandwich units [CoCp'Cp](+) and [FeCp'(η(6)-C6 Me6)](+) (Cp = η(5)-C5 H5; Cp' = η(5)-C5H4-) as hexafluorophosphate ([PF6](-)) salts are synthesized by ring-opening metathesis polymerization using Grubbs' third generation catalyst. Their electrochemical properties show full chemical and electrochemical reversibilities allowing fine determination of the copolymer molecular weight using Bard-Anson's electrochemical method by cyclic voltammetry.
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Cobalto/química , Complexos de Coordenação/química , Ferro/química , Polímeros/química , Catálise , Cátions/química , Técnicas Eletroquímicas , Compostos Ferrosos/química , Espectroscopia de Ressonância Magnética , Metalocenos , Oxirredução , Polímeros/síntese química , EspectrofotometriaRESUMO
Using the third-generation Grubbs catalyst, the living ring-opening metathesis polymerization of ferrocene/cobalticenium copolymers is conducted with theoretical numbers of 25 monomer units for each block, and their redox and electrochemical properties allow using the Bard-Anson electrochemical method to determine the number of metallocenyl units in each block.