930 resultados para Acute and subcronic toxicity


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Pre-reperfusion administration of intravenous (IV) metoprolol reduces infarct size in ST-segment elevation myocardial infarction (STEMI). This study sought to determine how this cardioprotective effect is influenced by the timing of metoprolol therapy having either a long or short metoprolol bolus-to-reperfusion interval. We performed a post hoc analysis of the METOCARD-CNIC (effect of METOprolol of CARDioproteCtioN during an acute myocardial InfarCtion) trial, which randomized anterior STEMI patients to IV metoprolol or control before mechanical reperfusion. Treated patients were divided into short- and long-interval groups, split by the median time from 15 mg metoprolol bolus to reperfusion. We also performed a controlled validation study in 51 pigs subjected to 45 min ischemia/reperfusion. Pigs were allocated to IV metoprolol with a long (−25 min) or short (−5 min) pre-perfusion interval, IV metoprolol post-reperfusion (+60 min), or IV vehicle. Cardiac magnetic resonance (CMR) was performed in the acute and chronic phases in both clinical and experimental settings. For 218 patients (105 receiving IV metoprolol), the median time from 15 mg metoprolol bolus to reperfusion was 53 min. Compared with patients in the short-interval group, those with longer metoprolol exposure had smaller infarcts (22.9 g vs. 28.1 g; p = 0.06) and higher left ventricular ejection fraction (LVEF) (48.3% vs. 43.9%; p = 0.019) on day 5 CMR. These differences occurred despite total ischemic time being significantly longer in the long-interval group (214 min vs. 160 min; p < 0.001). There was no between-group difference in the time from symptom onset to metoprolol bolus. In the animal study, the long-interval group (IV metoprolol 25 min before reperfusion) had the smallest infarcts (day 7 CMR) and highest long-term LVEF (day 45 CMR). In anterior STEMI patients undergoing primary angioplasty, the sooner IV metoprolol is administered in the course of infarction, the smaller the infarct and the higher the LVEF. These hypothesis-generating clinical data are supported by a dedicated experimental large animal study.

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The present study was carried out to evaluate the chemical and pharmacological properties of essential oil (EO) of Lavandula stoechas L. subsp. luisieri that is a spontaneous shrub widespread in Alentejo (Portugal). Oxygenated monoterpenes, as 1,8-cineole, lavandulol and necrodane derivatives are the main components of essential oil. It revealed important antioxidant activity with high ability to inhibit the lipid peroxidation and showed an outstanding effect against a wide spectrum of microorganisms, such as Gram-positive and Gram-negative bacteria and pathogenic yeasts. The analgesic effect studied in rats was dose dependent, reaching a maximum of 67 % at 60 min. with the dose of 200 mg/kg and the anti-inflammatory activity with this dose caused an inhibition in carrageenan-induced rat paw oedema (83 %) that is higher than dexamethasone 1 mg/Kg (69 %). Besides, animals exhibited a normal behaviour after EO administration revealing low toxicity. Essential oil of L. luisieri from Alentejo that presents important pharmacological properties and low toxicity is a promised candidate to be used as food supplement or in pharmaceutical applications.

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Despite numerous therapeutic interventions cancer is still today the second leading cause of death. A growing interest has been addressed to isothiocytanates and more recently, the 6- (methylsulfonyl) hexyl isothiocyanate (6-MITC), the main constituent of the rhizome of Wasabia Japonica, has stimulated the interest of researchers. Aim of the research was to study if 6-MITC is able to modulate the main mechanisms underlying chemopreventive process in leukemic cells lines, verify the selectivity of action and the safety of use in terms of mutagenicity. The study was conducted on different cell types. In particular, Jurkat and HL-60 cells were treated with increasing concentrations of 6-MITC and cell viability, induction of apoptosis, cell cycle analysis, autophagy modulation and stimulation of differentiation were evaluated by flow cytometry. PBL, the non-transformed counterparty of leukemia cells, was used to analyse the selectivity of action by studying the same mechanisms previously indicated. Finally, safety of use and antimutagenicity were studied in TK6 cells adopting an automated protocol in flow cytometry. The achieved results have demonstrated that isothiocyanate modulates many signaling pathways involved in chemopreventive mechanism. In fact, 6-MITC induces apoptosis of both transformed cells, limits tumor growth by slowing down the cell cycle of Jurkat cells and blocks HL-60 cell cycle, increases the autophagic flux and induces cytodifferentiation of promyelocytic HL-60 into macrophage and granulocytic phenotypes. Furthermore, the results obtained with 6-MITC on PBL from healthy donors suggest that the isothiocyante is a good selective cytotoxic agent. Essential feature of a good chemopreventive agent is selectivity toward cancer cells and low toxicity towards non-transformed cells. Finally, the analysis of the micronuclei revealed that 6-MITC is not mutagenic, ensuring safe use, and that instead, it is able to counteract the mutagenic activity of the aneuploidogen Vinblastine, demonstrating another important and interesting chemopreventive activity.

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Small cell lung cancer (SCLC) is an aggressive neuroendocrine tumor diagnosed at extended disease SCLC (ES-SCLC) stage in about 70% of cases. The new standard of treatment for patients with ES-SCLC is a combination of platinum-etoposide chemotherapy and atezolizumab or durvalumab, two programmed cell death ligand 1 (PD-L1) inhibitory monoclonal antibodies (mAb). However, the benefit derived from the addition of PD-L1 inhibitors to chemotherapy in ES-SCLC was limited and restricted to a subset of patients. The vascular endothelial growth factor (VEGF) is the most important pro-angiogenic factor implicated in cancer angiogenesis, which is abundant in SCLC and associated with poor prognosis. Antiangiogenic agents, such as bevacizumab, a humanized mAb against VEGF, added to platinum-etoposide chemotherapy improved progression-free survival in SCLC in two trials, but it did not translate into a benefit in overall survival. Nevertheless, VEGF has also acts as a mediator of an immunosuppressive microenvironment and its inhibition can revert the immune-suppressive tumor microenvironment and potentially enhance the efficacy of immunotherapies. Based on available preclinical data, we hypothesized that VEGF inhibition by bevacizumab could improve atezolizumab efficacy in a synergistic way and designed a phase II single-arm trial of bevacizumab in combination with carboplatin, etoposide, and atezolizumab as first-line treatment in ES-SCLC. The trial, which is still ongoing, enrolled 53 patients, including those with treated or untreated asymptomatic brain metastases (provided criteria are met), who received atezolizumab, bevacizumab, carboplatin and etoposide for 4-6 cycles (induction phase), followed by maintenance with atezolizumab and bevacizumab for a maximum of 18 total cycles or until disease progression, patient refusal, unacceptable toxicity. The evaluation of efficacy of the experimental combination in terms of 1-year overall survival rate is not yet mature (primary objective of the trial). The combination was feasible and the toxicity profile manageable (secondary objective of the trial).

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In this study, the production of bioactive secondary metabolites called "allelochemicals" by algae has been investigated, specifically focusing on polyunsaturated aldehydes (PUAs). PUAs are known to have adverse effects on planktonic grazers and on phytoplankton; however, their effect on benthic communities has been poorly studied. Macroalgae are ecosystem engineers that play an important role in the structure of the habitat and associated communities, presenting a great variability in their morphology and structural complexity, which is a primary factor in the structuring of associated communities. In recent decades, it has been seen how the introduction of invasive species can modify the benthic habitat structure, causing cascading effects on the trophic chain. The thesis includes several field and laboratory studies. Field studies examined aldehyde production by native and invasive macroalgal species (Sargassum muticum, in the Adriatic Sea, and Rugulopterix okamurae in the Strait of Gibraltar), their structural complexity, together with their associated phyto and meiobenthos. Two laboratory studies were conducted. The first one, based on microcosms experiments, evaluated the effect of PUA (produced by the diatom Skeletonema marinoi, or as decadienal analytical standard) on meiofauna. The second one evaluated the inhibitory effect of dilkamural, an allelopathic compound isolated from R. okamurae, on unicellular phototrophs. Our results showed that PUAs produced by macroalgae were species-specific and had a significant impact on the benthic community. The morphology of macroalgae was an important factor in shaping associated communities, particularly for microphytobenthos. Invasive species, such as S. muticum and R. okamurae, could reduce the biodiversity of native benthic communities and simplify the habitat. Dilkamural was hypothesized to be an allelochemical defense, and laboratory toxicity tests confirmed this hypothesis. Overall, this thesis sheds light on the importance of allelochemicals and macroalgal structural complexity in the benthic environment and highlights the potential impact of invasive species.

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Cleaning is one of the most important and delicate procedures that are part of the restoration process. When developing new systems, it is fundamental to consider its selectivity towards the layer to-be-removed, non-invasiveness towards the one to-be-preserved, its sustainability and non-toxicity. Besides assessing its efficacy, it is important to understand its mechanism by analytical protocols that strike a balance between cost, practicality, and reliable interpretation of results. In this thesis, the development of cleaning systems based on the coupling of electrospun fabrics (ES) and greener organic solvents is proposed. Electrospinning is a versatile technique that allows the production of micro/nanostructured non-woven mats, which have already been used as absorbents in various scientific fields, but to date, not in the restoration field. The systems produced proved to be effective for the removal of dammar varnish from paintings, where the ES not only act as solvent-binding agents but also as adsorbents towards the partially solubilised varnish due to capillary rise, thus enabling a one-step procedure. They have also been successfully applied for the removal of spray varnish from marble substrates and wall paintings. Due to the materials' complexity, the procedure had to be adapted case-by-case and mechanical action was still necessary. According to the spinning solution, three types of ES mats have been produced: polyamide 6,6, pullulan and pullulan with melanin nanoparticles. The latter, under irradiation, allows for a localised temperature increase accelerating and facilitating the removal of less soluble layers (e.g. reticulated alkyd-based paints). All the systems produced, and the mock-ups used were extensively characterised using multi-analytical protocols. Finally, a monitoring protocol and image treatment based on photoluminescence macro-imaging is proposed. This set-up allowed the study of the removal mechanism of dammar varnish and semi-quantify its residues. These initial results form the basis for optimising the acquisition set-up and data processing.

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Alpha-particle emitters, notably used in 224Ra-DaRT, have emerged as effective in overcoming radiation resistance and providing targeted cancer therapy. These emitters cause DNA double-strand breaks, visualizable in human lymphocytes. The 224Ra DaRT technique, using a decay chain from seeds, extends alpha particle range, achieving complete tumor destruction while sparing healthy tissue. This thesis examines a biokinetic model, validated with patient data, and a feasibility study on skin squamous cell carcinomas are discussed. The study reports 75% tumor complete response rate and 48% patients experiencing acute grade 2 toxicity, resolving within a month. An observed abscopal effect (AE), where tumor regression occurs at non-irradiated sites, is examined, highlighting DaRT's potential in triggering anti-tumor immune responses. This effect, coupled with DaRT's high-linear energy transfer (LET), suggests its superiority over low-LET radiation in certain clinical scenarios. Improvements to DaRT, including the use of an external radio-opaque template for treatment planning, are explored. This advancement aids in determining source numbers for optimal tumor coverage, enhancing DaRT’s safety. The thesis outlines a typical DaRT procedure, from tumor measurements to source assessment and administration, emphasizing the importance of precise seed positioning. Furthermore, the thesis discusses DaRT's potential in treating prostate cancer, a prevalent global health issue, by offering an alternative to traditional salvage therapies. DaRT seeds, delivering alpha particle-based interstitial radiation, require precision in seed insertion due to their limited tissue range. In conclusion, the thesis advocates for DaRT's role in treating solid tumors, emphasizing its improved radiobiological potency and potential benefits over beta and gamma source-based therapies. Ongoing studies are assessing DaRT's feasibility in treating various solid tumors, including pancreatic, breast, prostate, and vulvar malignancies, suggesting a promising future in cancer treatment.

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The treatment of subglottic stenosis in children remains a challenge for the otolaryngologist and may involve procedures such as endoscopy, open surgery, and often both. In the recent past, high-pressure balloons have been used in endoscopic treatment due to their relative facility and high success rates. To report success rates in the treatment of acquired subglottic stenosis with balloon laryngoplasty in children and identify predictive factors for the success of the technique and its complications. Descriptive, prospective study of children who were diagnosed with acquired subglottic stenosis and underwent balloon laryngoplasty as the primary treatment. Balloon laryngoplasty was performed in 48 children with an average age of 20.7 months: 31 presented with chronic subglottic stenosis and 17 with acute stenosis. Success rate was 100% for acute and 39% for chronic subglottic stenosis. Success was significantly associated with several factors, including recently acquired stenosis, initial grade of stenosis, younger patient age, and the absence of tracheotomy. Complications were transitory dysphagia observed in three children and a submucosal cyst in one of the patients. Balloon laryngoplasty may be considered as a first line of treatment for acquired subglottic stenosis. In acute cases, the success rate was 100%, and even though results are less promising in chronic cases, complications were not significant and the patients can undergo open surgery without contraindications. Predictive factors of success were acute stenosis, less severe grades of stenosis, younger patient age, and the absence of tracheotomy.

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A number of studies have proposed an anti-diabetic effect for tarchonanthuslactone based on its structural similarity with caffeic acid, a compound known for its blood glucose-reducing properties. However, the actual effect of tarchonanthuslactone on blood glucose level has never been tested. Here, we report that, in opposition to the common sense, tarchonanthuslactone has a glucose-increasing effect in a mouse model of obesity and type 2 diabetes mellitus. The effect is acute and non-cumulative and is present only in diabetic mice. In lean, glucose-tolerant mice, despite a slight increase in blood glucose levels, the effect was not significant.

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Resistant hypertension (RHTN) is a multifactorial disease characterized by blood pressure (BP) levels above goal (140/90 mmHg) in spite of the concurrent use of three or more antihypertensive drugs of different classes. Moreover, it is well known that RHTN subjects have high prevalence of left ventricular diastolic dysfunction (LVDD), which leads to increased risk of heart failure progression. This review gathers data from studies evaluating the effects of phosphodiesterase-5 (PDE-5) inhibitors (administration of acute sildenafil and short-term tadalafil) on diastolic function, biochemical and hemodynamic parameters in patients with RHTN. Acute study with sildenafil treatment found that inhibition of PDE-5 improved hemodynamic parameters and diastolic relaxation. In addition, short-term study with the use of tadalafil demonstrated improvement of LVDD, cGMP and BNP-32 levels, regardless of BP reduction. No endothelial function changes were observed in the studies. The findings of acute and short-term studies revealed potential therapeutic effects of IPDE-5 drugs on LVDD in RHTN patients.A Hipertensão arterial resistente (HAR) é uma doença multifatorial caracterizada por níveis pressóricos acima das metas (140/90 mmHg), a despeito de tratamento farmacológico otimizado de 3 ou mais fármacos anti-hipertensivos de diferentes classes. Pacientes diagnosticados como hipertensos resistentes apresentam alta prevalência de disfunção diastólica do ventrículo esquerdo (DDVE) que proporciona risco aumentado para insuficiência cardíaca. Esta revisão reúne dados de estudos prévios avaliando os efeitos dos inibidores de fosfodiesterase-5 (PDE-5) (administração aguda de sildenafil e de curto prazo de tadalafil) na função diastólica e nos parâmetros bioquímicos e hemodinâmicos em pacientes com HAR. O estudo agudo com sildenafil demonstrou que a inibição da PDE-5 melhorou os parâmetros hemodinâmicos e de relaxamento diastólico. Além disso, o estudo curto prazo com o uso de tadalafil revelou melhora da DDVE e dos níveis de GMPc e BNP-32, independente de redução de pressão arterial. A função endotelial não apresentou alteração com ambos os tratamentos. Os resultados dos estudos agudo e de curto prazo sugerem efeitos terapêuticos potenciais dos fármacos inibidores da PDE-5 na disfunção diastólica em pacientes com HAR.

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Micropartículas produzidas a partir de polímeros sintéticos têm sido amplamente utilizadas na área farmacêutica para encapsulação de princípios ativos. Essas micropartículas apresentam as vantagens de proteção do princípio ativo, mucoadesão e gastrorresistência, melhor biodisponibilidade e maior adesão do paciente ao tratamento. Além disso, utiliza menores quantidade de princípio ativo para obtenção do efeito terapêutico proporcionando diminuição dos efeitos adversos locais, sistêmicos e menor toxidade. Os polímeros sintéticos empregados na produção das micropartículas são classificados biodegradáveis ou não biodegradáveis, sendo os biodegradáveis mais utilizados por não necessitam ser removidos cirurgicamente após o término de sua ação. A produção das micropartículas poliméricas sintéticas para encapsulação tanto de ativos hidrofílicos quanto hidrofóbicos pode ser emulsificação por extração e/ou evaporação do solvente; coacervação; métodos mecânicos e estão revisados neste artigo evidenciando as vantagens, desvantagens e viabilidade de cada metodologia. A escolha da metodologia e do polímero sintético a serem empregados na produção desse sistema dependem da aplicação terapêutica requerida, bem como a simplicidade, reprodutibilidade e factibilidade do aumento de escala da produção.

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Introdução: Revisar os casos de doenças febris exantemáticas com IgM reagente contra o sarampo, no estado de São Paulo, Brasil, durante os cinco anos seguidos a interrupção da transmissão do vírus do sarampo. Métodos: Nós revisamos 463 casos de doenças febris exantemáticas com IgM reagente contra o sarampo, no estado de São Paulo, Brasil, de 2000 a 2004. Indivíduos vacinados contra o sarampo 56 dias antes da coleta de amostra foram considerados expostos à vacina. Soros da fase aguda e de convalescença foram testados para a evidência de infecção de sarampo, rubéola, parvovírus B19 e herpes vírus 6. Na ausência de soroconversão para imunoglobulina G contra o sarampo, casos com IgM reagente contra o sarampo foram considerados falsos positivos em pessoas com evidência de outras infecções virais. Resultados: Entre as 463 pessoas com doenças febris exantemáticas que testaram positivo para anticorpos IgM contra o sarampo durante o período, 297 (64 por cento) pessoas foram classificadas como expostas à vacina. Entre os 166 casos não expostos à vacina, 109 (66 por cento) foram considerados falsos positivos baseado na ausência de soroconversão, dos quais 21 (13 por cento) tiveram evidência de infecção por vírus da rubéola, 49 (30 por cento) parvovírus B19 e 28 (17 por cento) infecção por herpes vírus humano 6. Conclusões: Após a interrupção da transmissão do vírus do sarampo é necessária exaustiva investigação dos casos com IgM reagente contra o sarampo, especialmente dos casos não expostos à vacina. Testes laboratoriais para etiologias das doenças febris exantemáticas ajudam na interpretação destes casos

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The pivotal role of spleen CD4(+) T cells in the development of both malaria pathogenesis and protective immunity makes necessary a profound comprehension of the mechanisms involved in their activation and regulation during Plasmodium infection. Herein, we examined in detail the behaviour of non-conventional and conventional splenic CD4(+) T cells during P. chabaudi malaria. We took advantage of the fact that a great proportion of CD4(+) T cells generated in CD1d(-/-) mice are I-A(b)-restricted (conventional cells), while their counterparts in I-Ab(-/-) mice are restricted by CD1d and other class IB major histocompatibility complex (MHC) molecules (non-conventional cells). We found that conventional CD4(+) T cells are the main protagonists of the immune response to infection, which develops in two consecutive phases concomitant with acute and chronic parasitaemias. The early phase of the conventional CD4(+) T cell response is intense and short lasting, rapidly providing large amounts of proinflammatory cytokines and helping follicular and marginal zone B cells to secrete polyclonal immunoglobulin. Both TNF-alpha and IFN-gamma production depend mostly on conventional CD4(+) T cells. IFN-gamma is produced simultaneously by non-conventional and conventional CD4(+) T cells. The early phase of the response finishes after a week of infection, with the elimination of a large proportion of CD4(+) T cells, which then gives opportunity to the development of acquired immunity. Unexpectedly, the major contribution of CD1d-restricted CD4(+) T cells occurs at the beginning of the second phase of the response, but not earlier, helping both IFN-gamma and parasite-specific antibody production. We concluded that conventional CD4(+) T cells have a central role from the onset of P. chabaudi malaria, acting in parallel with non-conventional CD4(+) T cells as a link between innate and acquired immunity. This study contributes to the understanding of malaria immunology and opens a perspective for future studies designed to decipher the molecular mechanisms behind immune responses to Plasmodium infection.

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This paper presents the lifecycle assessment (LCA) of fuel ethanol, as 100% of the vehicle fuel, from sugarcane in Brazil. The functional unit is 10,000 km run in an urban area by a car with a 1,600-cm(3) engine running on fuel hydrated ethanol, and the resulting reference flow is 1,000 kg of ethanol. The product system includes agricultural and industrial activities, distribution, cogeneration of electricity and steam, ethanol use during car driving, and industrial by-products recycling to irrigate sugarcane fields. The use of sugarcane by the ethanol agribusiness is one of the foremost financial resources for the economy of the Brazilian rural area, which occupies extensive areas and provides far-reaching potentials for renewable fuel production. But, there are environmental impacts during the fuel ethanol lifecycle, which this paper intents to analyze, including addressing the main activities responsible for such impacts and indicating some suggestions to minimize the impacts. This study is classified as an applied quantitative research, and the technical procedure to achieve the exploratory goal is based on bibliographic revision, documental research, primary data collection, and study cases at sugarcane farms and fuel ethanol industries in the northeast of SA o pound Paulo State, Brazil. The methodological structure for this LCA study is in agreement with the International Standardization Organization, and the method used is the Environmental Design of Industrial Products. The lifecycle impact assessment (LCIA) covers the following emission-related impact categories: global warming, ozone formation, acidification, nutrient enrichment, ecotoxicity, and human toxicity. The results of the fuel ethanol LCI demonstrate that even though alcohol is considered a renewable fuel because it comes from biomass (sugarcane), it uses a high quantity and diversity of nonrenewable resources over its lifecycle. The input of renewable resources is also high mainly because of the water consumption in the industrial phases, due to the sugarcane washing process. During the lifecycle of alcohol, there is a surplus of electric energy due to the cogeneration activity. Another focus point is the quantity of emissions to the atmosphere and the diversity of the substances emitted. Harvesting is the unit process that contributes most to global warming. For photochemical ozone formation, harvesting is also the activity with the strongest contributions due to the burning in harvesting and the emissions from using diesel fuel. The acidification impact potential is mostly due to the NOx emitted by the combustion of ethanol during use, on account of the sulfuric acid use in the industrial process and because of the NOx emitted by the burning in harvesting. The main consequence of the intensive use of fertilizers to the field is the high nutrient enrichment impact potential associated with this activity. The main contributions to the ecotoxicity impact potential come from chemical applications during crop growth. The activity that presents the highest impact potential for human toxicity (HT) via air and via soil is harvesting. Via water, HT potential is high in harvesting due to lubricant use on the machines. The normalization results indicate that nutrient enrichment, acidification, and human toxicity via air and via water are the most significant impact potentials for the lifecycle of fuel ethanol. The fuel ethanol lifecycle contributes negatively to all the impact potentials analyzed: global warming, ozone formation, acidification, nutrient enrichment, ecotoxicity, and human toxicity. Concerning energy consumption, it consumes less energy than its own production largely because of the electricity cogeneration system, but this process is highly dependent on water. The main causes for the biggest impact potential indicated by the normalization is the nutrient application, the burning in harvesting and the use of diesel fuel. The recommendations for the ethanol lifecycle are: harvesting the sugarcane without burning; more environmentally benign agricultural practices; renewable fuel rather than diesel; not washing sugarcane and implementing water recycling systems during the industrial processing; and improving the system of gases emissions control during the use of ethanol in cars, mainly for NOx. Other studies on the fuel ethanol from sugarcane may analyze in more details the social aspects, the biodiversity, and the land use impact.

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Thioridazine (THD) is a commonly prescribed phenotiazine neuroleptic drug, which is extensively biotransformed in the organism producing as main metabolites sulfoxides and a sulfone by sulfur oxidation Significant differences have been observed in the activity of the THD enantiomers as well as for its main metabolites, and enantioselectivity phenomena have been proved in the metabolic pathway. Here the assignment of the absolute configuration at the sulfur atom of enantiomeric THD-2-sulfoxide (THD-2-SO) has been carried out by circular dichroism (CD) spectroscopy The stereoisomers were separated by HPLC on Chiralpak AS column, recording the CD spectra for the two collected enantiomeric fractions The theoretical electronic CD spectrum has been obtained by the TDDFT/B3LYP/6-31G*. as Boltzmann averaging of the contributions calculated for the most stable conformations of the drug The comparison of the simulated and experimental spectra allowed the absolute configuration at the sulfur atom of the four THD-2-SO stereoisomers to be assigned The developed method should be useful for a reliable correlation between stereochemistry and activity and/or toxicity