Geoclimatic drivers of diversification in the largest arid and semi-arid environment of the Neotropics: Perspectives from phylogeography.

The South American Dry Diagonal, also called the Diagonal of Open Formations, is a large region of seasonally dry vegetation extending from northeastern Brazil to northern Argentina, comprising the Caatinga, Cerrado, and Chaco subregions. A growing body of phylogeography literature has determined that a complex history of climatic changes coupled with more ancient geological events has produced a diverse and endemic-rich Dry Diagonal biota. However, the exact drivers are still under investigation, and their relative strengths and effects are controversial. Pleistocene climatic fluctuations structured lineages via vegetation shifts, refugium formation, and corridors between the Amazon and Atlantic forests. In some taxa, older geological events, such as the reconfiguration of the São Francisco River, uplift of the Central Brazilian Plateau, or the Miocene inundation of the Chaco by marine incursions, were more important. Here, we review the Dry Diagonal phylogeography literature, discussing each hypothesized driver of diversification and assessing degree of support. Few studies statistically test these hypotheses, with most support drawn from associating encountered phylogeographic patterns such as population structure with the timing of ancient geoclimatic events. Across statistical studies, most hypotheses are well supported, with the exception of the Pleistocene Arc Hypothesis. However, taxonomic and regional biases persist, such as a proportional overabundance of herpetofauna studies, and the under-representation of Chaco studies. Overall, both Pleistocene climate change and Neogene geological events shaped the evolution of the Dry Diagonal biota, though the precise effects are regionally and taxonomically varied. We encourage further use of model-based analyses to test evolutionary scenarios, as well as interdisciplinary collaborations to progress the field beyond its current focus on the traditional set of geoclimatic hypotheses.

3-Halochromones Through Oxidative α-Halogenation of Enaminones and its Photophysical Investigation: Another Case of Photo-induced Partially Aromatised Intramolecular Charge Transfer?

A versatile synthesis strategy for fluorescent 3-halo-4H-chromen-4-one derivatives is reported. The method involves the oxidative α-halogenation of enaminones performed by an efficient and sustainable oxidation system. The use of Oxone® in combination with KCl, KBr, or KI enables the preparation of 3-chloro-, 3-bromo-, or 3-iodo-4H-chromen-4-one in good to excellent yields, with great functional group tolerance where the protocol is amenable to gram-scale synthesis. The analysis of the photophysical properties of the presented 4H-chromen-4-one showed absorption in the UV region and fluorescence emission in the violet-to-cyan region with a relatively large Stokes shift. In solution, all compounds present a dual fluorescence emission, regardless of the solvent, assigned to a partially aromatised intramolecular charge transfer mechanism, considering the presence of a pseudo-aromatic ring in the chromone scaffold and the absence of the influence of substituent electronic features in optical behaviour.

Brazilian guidelines on chronic venous disease of the Brazilian Society of Angiology and Vascular Surgery.

The Brazilian Society of Angiology and Vascular Surgery has set up a committee to provide new evidence-based recommendations for patient care associated with chronic venous insufficiency. Topics were divided in five groups: 1. Classification, 2. Diagnosis, 3. Conservative or non-invasive treatment, 4. Invasive treatment and 5. Treatment of small vessels. This last series is closely related to the activities of Brazilian angiologists and vascular surgeons, who are heavily involved in the treatment of small superficial veins. These guidelines are intended to assist in clinical decision-making for attending physicians and health managers. The decision to follow a guideline recommendation should be made by the responsible physician on a case-by-case basis taking into account the patient's specific condition, as well as local resources, regulations, laws, and clinical practice recommendations.

A Sociedade Brasileira de Angiologia e de Cirurgia Vascular organizou uma comissão para fornecer novas recomendações baseadas em evidências sobre questões críticas de atendimento ao paciente com insuficiência venosa crônica. São abordados aqui os temas de classificação, diagnóstico, tratamento conservador, tratamento invasivo e tratamento de pequenos vasos. Esta última série está muito relacionada à atividade de angiologistas e cirurgiões vasculares, que possuem forte atuação no tratamento de pequenas veias superficiais. Estas diretrizes destinam-se a auxiliar na tomada de decisões clínicas de médicos assistentes e gestores de saúde. A decisão de seguir uma recomendação de diretriz deve ser feita pelo médico responsável caso a caso, levando em consideração a condição específica do paciente, bem como recursos locais, regulamentos, leis e recomendações de prática clínica.

Organosulfur and Organoselenium Functionalized Benzimidazo[1,2-a]quinolines: From Experimental and Theoretical Photophysics to All-Solution-Processed OLEDs.

In this study, we present the synthesis of benzimidazo[1,2-a] quinoline-based heterocycles bearing organosulfur and organoselenium moieties through transition-metal-free cascade reactions involving a sequential intermolecular aromatic nucleophilic substitution (SNAr). Both sulfur and selenium derivatives presented absorption maxima located around 355 nm related to spin and symmetry allowing electronic 1π-π* transitions, and fluorescence emission at the violet-blue region (~440 nm) with relatively large Stokes shift. The fluorescence quantum yields were slightly influenced by the chalcogen, with the sulfur derivatives presenting higher values than the selenium analogs. In this sense, the quantum yields for selenium derivatives can probably be affected by the intersystem crossing or even the photoinduced electron transfer process (PET). The compounds were successfully applied in all-solution-processed organic light-emitting diodes (OLEDs), where poly(9-vinylcarbazole) was employed as a dispersive matrix generating single-layer device cells. The obtained electroluminescence spectra are a sum of benzimidazo[1,2-a]quinolines and PVK singlet and/or triplet emissive states, according to their respective energy band gaps. The best diode rendered a luminance of 25.4 cd⋅m-2 with CIE (0.17, 0.14) and current efficiency of 20.2 mcd⋅A-1, a fivefold improvement in comparison to the PVK device that was explained by a 50-fold increase of charge-carriers electrical mobility.

Influence of compression therapy following varicose vein surgery: a prospective randomized study.

Background: The use of compression dressings after phlebectomy is based solely on clinical experience due to the lack of a unified set of definitive recommendations, which makes clinical practice extremely heterogeneous. Objectives: To evaluate compression therapy with elastic stockings for 7 days after phlebectomy. Methods: We randomly allocated 104 lower limbs with disease classified as C1 and C2 to 1 of 2 groups: an intervention group (64 limbs) - wearing elastic compression stockings for the first 7 days after phlebectomy; or a control group (40 limbs) - given conventional bandaging for 24 hours postoperatively. We compared clinical response by analyzing the evolution of symptoms, hematoma formation, and preoperative vs. postoperative limb volume. Results: Pain (median 1.0 vs. 1.5, p=0.0320) and limb volume (mean 43.7 vs. 99.8, p=0.0071) were significantly improved in patients wearing elastic compression stockings for 7 days after phlebectomy compared with controls. Conclusions: Use of elastic compression therapy for 7 days after phlebectomy was effective for improving pain and lower limb volume.

Contexto: O uso de curativos após flebectomia é baseado apenas na experiência clínica, visto que não existe um conjunto unificado de recomendações definitivas, o que torna a prática clínica extremamente variável. Objetivos: Avaliar o uso de terapia elástica compressiva por 7 dias após flebectomia. Métodos: Cento e quatro membros inferiores, classificados como CEAP C1 e C2, foram randomizados em dois grupos: grupo de intervenção (64 membros) ­ uso de meia elástica por 24 horas após a cirurgia ­ e grupo controle (40 membros) ­ uso de curativo convencional por 7 dias após a cirurgia. A resposta clínica foi comparada por meio de análise da evolução dos sintomas, de hematoma e do volume dos membros antes e depois da cirurgia. Resultados: Os pacientes submetidos a terapia compressiva elástica apresentaram melhora significativa na dor (mediana 1,0 vs. 1,5; p=0,0320) e no volume dos membros (média 43,7 vs. 99,8; p=0,0071) em comparação ao grupo controle. Conclusões: O emprego da terapia compressiva elástica por 7 dias após flebectomia mostrou-se efetivo na melhora da dor e do volume dos membros inferiores.

Thermodiffusion of CO2 in Water by Nonequilibrium Molecular Dynamics Simulations.

The components of a fluid mixture may segregate due to the Soret effect, a coupling phenomenon in which mass flux can be induced by a thermal gradient. In this work, we evaluate systematically the thermodiffusion of the CO2-H2O mixture, and the influence of the geothermal gradient on CO2 segregation in deep saline aquifers in CO2 storage. The eHeX method, a nonequilibrium molecular dynamics simulation approach, is judiciously selected to simulate the phenomenon. At 350 K, 400 bar, and CO2 mole fraction of 0.02 (aquifer conditions), CO2 accumulates on the cold side, and the thermal diffusion factor is close to 1 in a number of force fields. The lower the temperature, the higher is the separation and the thermal diffusion factor. In colder regions, water self-association is stronger, whereas the CO2-H2O cross-association and the CO2-CO2 interactions enhance at higher temperatures. Thermodiffusion and gravitational segregation have opposite effects on CO2 segregation. At typical subsurface conditions, the Soret effect is more pronounced than gravity segregation, and CO2 concentrates in the top (colder region). Our work sets the stage to model the effect of electrolytes on CO2 segregation in subsurface aquifers and other areas of interest.

Phenotypical Differences between Leishmania (Leishmania) amazonensis PH8 and LV79 Strains May Impact Survival in Mammal Host and in Phlebotomine Sand Flies.

We previously showed that L. (Leishmania) amazonensis promastigotes and amastigotes of the PH8 strain generated larger lesions in mice than LV79, and that lesion-derived amastigotes from the two strains differ in their proteomes. We recently reported that PH8 promastigotes are more phagocytized by macrophages. Promastigotes' membrane-enriched proteomes showed several differences, and samples of each strain clustered based on proteomes. In this paper, we show phenotypic differences between PH8 and LV79 promastigotes that may explain the higher virulence of PH8. We compared in vitro macrophage infections by day 4 (early) and day 6 (late stationary phase) cultures, resistance to complement, and LPG characteristics. PH8 promastigotes showed a higher infectivity and were more resistant to murine complement. LPG was different between the strains, which may influence the interaction with macrophages and survival to complement. We compared the infection of the permissive vector Lutzomyia longipalpis. PH8 was more abundant in the vector's gut 72 h after feeding, which is a moment where blood digestion is finished and the parasites are exposed to the gut environment. Our results indicate that PH8 promastigotes are more infective, more resistant to complement, and infect the permissive vector more efficiently. These data suggest that PH8 is probably better adapted to the sand fly and more prone to survive in the vertebrate host.

Herpetofauna of protected areas in the Caatinga VIII: An updated checklist for the Serra das Confusões region with new data from Serra Vermelha, Piauí, Brazil / Herpetofauna das áreas protegidas da Caatinga VIII: Um inventário atualizado para a região da Serra das Confusões com novos dados da Serra Vermelha, Piauí, Brazil

Abstract It is repeatedly stressed the need to characterize the extant biodiversity in tropical ecosystems. However, inventory studies are still progressing slowly in dry ecosystems, leading to the underestimation of their true biodiversity and hindering conservation efforts. In this study, we present primary and secondary data, along with an updated list of amphibians and reptiles from two localities in the São Francisco-Gurguéia region in Piauí. Additionally, we compare the species composition between nine areas within the Caatinga, which were sampled using standardized methods over the past ten years, to examine broader spatial patterns of community composition. To survey reptiles and amphibians, we employed similar methods and sampling efforts in two areas within the Serra das Confusões National Park (SCNP) region. Our surveys recorded a total of 73 species of amphibians and reptiles, of which 24 are new distribution records for the SCNP region. Consequently, our findings increase the known herpetofauna in the region to 94 species. Despite their proximity, the two sites in the SCNP region exhibited only 42% similarity in species composition, and they differed significantly from other areas within the Caatinga. Furthermore, even the closer Caatinga areas presented differences in species composition, highlighting the necessity to evaluate biodiversity across the landscape and contribute to understanding biogeographic patterns.

Resumo É repetidamente enfatizada a necessidade de caracterizar a biodiversidade vivente em ecossistemas tropicais. No entanto, os estudos de inventário ainda estão progredindo lentamente em ecossistemas secos, levando à subestimação de sua verdadeira biodiversidade e dificultando os esforços de conservação. Neste estudo, apresentamos dados primários e secundários, juntamente com uma lista atualizada de anfíbios e répteis de duas localidades na região de São Francisco-Gurguéia, do Piauí. Além disso, comparamos a composição de espécies entre nove áreas dentro da Caatinga, que foram amostradas usando métodos padronizados nos últimos dez anos, para examinar padrões espaciais mais amplos de composição da comunidade. Para estudar répteis e anfíbios, utilizamos métodos e esforços de amostragem semelhantes em duas áreas na região do Parque Nacional da Serra das Confusões (PNSC). Nossos levantamentos registraram um total de 73 espécies de anfíbios e répteis, das quais 24 são novos registros de distribuição para a região do PNSC. Consequentemente, nossos resultados aumentam a herpetofauna conhecida na região para 94 espécies. Apesar da proximidade, os dois locais na região do PNSC exibiram apenas 42% de similaridade na composição de espécies e diferiram significativamente de outras áreas dentro da Caatinga. Mesmo áreas mais próximas da Caatinga apresentaram diferenças na composição de espécies, destacando a necessidade de avaliar a biodiversidade em toda a paisagem e contribuir para a compreensão de padrões biogeográficos.

Lifestyle and breast cancer: review article

The aim of this study was to improve our knowledge about carcinogenesis and lifestyle, given their impact on the occurrence of breast cancer, emphasizing the importance of lifestyle changes as a preventive factor in the development of the disease. We conducted a bibliographic review with the analysis of 31 articles in English and Portuguese. As a result, the articles selected for study showed that factors such as diet, alcohol intake, smoking, obesity, physical activity, occupational exposure, hormonal factors (hormone therapy, contraceptives) and reproductive factors (menarche, menopause, nulliparity, pregnancy, breastfeeding) have a protective or risk effect on breast cancer. We conclude that eating healthy, with fruits, vegetables and greens, practicing moderate physical activity, avoiding alcoholic beverages and breastfeeding exclusively reduce the risk of developing breast cancer by 28%. Therefore, it is necessary to make the public aware of these modifiable risk factors

Advances in breast imaging: a review on where we are and where we are going

Breast radiology has undergone significant advances in recent years, and, naturally, several possibilities open up for attending physicians. Concomitantly, it increases the responsibility to keep up to date and provide the best care for each patient. Aware of the complex implications that the implementation of some of the technological advances may bring, such as increased costs, limited availability of equipment, and a potential increase in examination time, the objective of this study is to carry out a narrative review and provide a collection of advances that, in our opinion, are already gaining ground and should be consolidated in clinical practice. We will discuss new breast imaging methods that can be used both for screening and for the diagnostic investigation of breast lesions and we will summarize the most relevant aspects of each of them, addressing the technique, applicability, positive aspects, and limitations of each modality in a standardized way. (AU)

Leptodactylus vastos (LEPTODACTYLIDAE) PREDATION ON AN ENDEMIC FROG, AND A COMPILATION OF ITS DIET / Depredación de Leptodactylus vastus (Leptodactylidae) en una rana endémica y una recopilación de su dieta

RESUMEN La composición de la dieta constituye información básica sobre la historia natural de la especie. A pesar de la cantidad de datos adquiridos en los últimos años, aún queda mucho por conocer, especialmente para especies geográficamente extendidas. Aquí compilamos los elementos dietéticos disponibles de Leptodactylus vastus y reportamos el primer evento de depredación de Rupirana cardosoi por un juvenil de L. vastus. El hecho de que estas especies sean sintópicas en la región probablemente resultó en este nuevo evento de depredación. A diferencia de las observaciones previas de depredación de L. vastus, los especímenes que observamos no presentan una diferencia notable en el tamaño corporal, pero L. vastus fue capaz de casi tragar R. cardosoi, en coherencia con los hallazgos de que el tamaño de la boca está relacionado con la selección de presas en los anuros. Además, nuestra revisión de la literatura mostró que L. vastus es un depredador generalista y oportunista, que se alimenta de pequeños vertebrados (Amphibia, Squamata y Mammalia).

ABSTRACT Diet composition constitutes basic information on the natural history of the species. Despite the amount of data acquired in the last years, much remains to be known specially for geographically widespread species. Here we compiled the available dietary items of Leptodactylus vastus and report the first predation event upon Rupirana cardosoi by a juvenile L. vastus. The fact these species are syntopic in the region probably resulted in this novel predation event. Different from previous L. vastus predation observations, the specimens we observed do not present a striking difference in body size, but L. vastus was able to almost swallow L. cardosoi, coherent with findings that mouth size is related to prey selection in anurans. Also, our literature review showed that L. vastus is a generalist and opportunistic predator, that prey upon small vertebrates (Amphibia, Squamata, and Mammalia).

Patterns of flow drainage from varicose veins originating in the incompetent great saphenous vein.

Background: Chronic venous insufficiency affects the lives of many people and therefore constitutes a public health problem. Knowledge of the drainage patterns of reflux from varicose veins secondary to incompetent saphenous veins is essential to define the best therapeutic management. Objectives: To determine the reflux drainage patterns from varicose veins originating in incompetent GSV, the prevalence of perforating veins (PV), and their relationships with symptoms. Methods: 55 ultrasound reports were analyzed to determine the drainage patterns of reflux from the GSV, location and diameter of PV drainage, and staging of symptoms. Results: In 64% of the sample, reflux from varicose veins drained to PVs, in 4% reflux drained to the GSV itself, in another 4% drainage was to the small saphenous vein, and in 29% drainage was to varicose trunk veins in which no direct communication with the deep system could be identified. No associations were observed between symptoms and reflux drainage patterns or PV diameters. Conclusions: For this sample, PVs were responsible for draining flow from varicose veins in 64% of cases. Neither PV diameters nor GSV reflux patterns were associated with severity of symptoms.

Introdução: A insuficiência venosa crônica impacta a vida de muitas pessoas, constituindo-se, assim, como um problema de saúde pública. Conhecer o padrão de drenagem do refluxo das varizes associadas à veia safena incompetente é fundamental para definir a melhor programação terapêutica. Objetivos: Determinar os padrões de drenagem do refluxo de varizes originadas da veia safena magna incompetente, a prevalência de veias perfurantes e a relação com os sintomas. Métodos: Foram analisados 55 registros ultrassonográficos de pacientes com refluxo da veia safena magna para determinar padrões de drenagem do refluxo dessa veia, pontos de refluxo das varizes, localização e diâmetro das perfurantes de drenagem e graduação dos sintomas. Resultados: O principal padrão de refluxo encontrado foi originado da junção safenofemoral com comprometimento proximal da veia safena magna. Em 64% dos pacientes, o refluxo das varizes drenou para veias perfurantes - 4% drenavam para a própria veia safena magna; em outros 4%, a drenagem era para a veia safena parva; e, em 29%, a drenavam destinava-se para varizes tronculares em que não se identificou comunicação direta com o sistema venoso profundo. Não foi observada associação dos sintomas com os padrões de drenagem do refluxo ou diâmetro das perfurantes. Conclusão: Para essa amostra, as veias perfurantes foram responsáveis pelo escoamento do fluxo oriundo das varizes em 64% dos casos. O diâmetro das veias perfurantes e o padrão de refluxo da veia safena não estiveram associados à gravidade dos sintomas.

Evidence of a Photoinduced Electron-Transfer Mechanism in the Fluorescence Self-quenching of 2,5-Substituted Selenophenes Prepared through In Situ Reduction of Elemental Selenium in Superbasic Media.

A series of new 2,5-disubstituted selenophene derivatives are described from elemental selenium and 1,3-diynes in superbasic media. The activation of elemental selenium in a KOH/DMSO system allows cyclization with conjugated diynes at room temperature. The cyclization reaction is extended to a broad range of functional groups, for which photophysics were experimentally and theoretically investigated. The selenophene derivatives present absorption maxima in the UV-A region and fluorescence emission in the violet-to-blue region. Fluorescence decay profiles were obtained showing a monoexponential decay with fast fluorescence lifetimes (∼0.118 ns), as predicted by the Strickler-Berg relations. In general, in both investigations, no dependence on the solvent polarity on the absorption and emission maxima location was observed. On the other hand, solvents and substituents are shown to play a role in the fluorescence quantum yield values. In addition, a fluorescence self-quenching behavior could be observed, related to a photoinduced electron-transfer mechanism. Theoretical calculations performed at the MP2/ADC(2)/cc-pVDZ level of theory were performed in order to investigate the photophysical features of this series of selenophene derivatives.

A novel receptor for platelet-activating factor and lysophosphatidylcholine in Trypanosoma cruzi.

The lipid mediators, platelet-activating factor (PAF) and lysophosphatidylcholine (LPC), play relevant pathophysiological roles in Trypanosoma cruzi infection. Several species of LPC, including C18:1 LPC, which mimics the effects of PAF, are synthesized by T. cruzi. The present study identified a receptor in T. cruzi, which was predicted to bind to PAF, and found it to be homologous to members of the progestin and adiponectin family of receptors (PAQRs). We constructed a three-dimensional model of the T. cruzi PAQR (TcPAQR) and performed molecular docking to predict the interactions of the TcPAQR model with C16:0 PAF and C18:1 LPC. We knocked out T. cruzi PAQR (TcPAQR) gene and confirmed the identity of the expressed protein through immunoblotting and immunofluorescence assays using an anti-human PAQR antibody. Wild-type and knockout (KO) parasites were also used to investigate the in vitro cell differentiation and interactions with peritoneal mouse macrophages; TcPAQR KO parasites were unable to react to C16:0 PAF or C18:1 LPC. Our data are highly suggestive that PAF and LPC act through TcPAQR in T. cruzi, triggering its cellular differentiation and ability to infect macrophages.

Improvement of semen parameters after coil embolization of varicoceles: a systematic review.

This systematic review was conducted in accordance with the 2009 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, including clinical studies in which one of the outcomes was semen parameter improvement after varicocele embolization using coils only. The objective of the review was to assess the evidence on the role of embolization using coils alone for semen parameter improvement in men with varicocele, since embolization using coils is the most cost-effective method of varicocele repair. Study quality was assessed using the methodological index for non-randomized studies (MINORS). Out of six retrospective and two prospective observational or comparative clinical studies involving 701 patients, semen concentration improved significantly in all five studies that assessed this parameter. Mean semen motility improved significantly in seven studies. The impact of embolization on semen density could not be analyzed.

Trata-se de uma revisão sistemática conduzida de acordo com o PRISMA 2009 (Principais Itens para Relatar Revisões Sistemáticas e Metanálises) que incluiu estudos em que a melhora dos parâmetros seminais tenha sido um dos desfechos. Esta revisão foi realizada com o objetivo de avaliar as evidências sobre o papel da embolização com uso apenas de molas na melhora de parâmetros seminais em homens com varicocele, uma vez que a embolização apenas com molas é o método com melhor custo-benefício para o reparo de varicoceles. A qualidade dos estudos foi analisada com o índice MINORS. Em seis estudos clínicos retrospectivos e em outros dois prospectivos observacionais ou comparativos, a concentração seminal melhorou significativamente em todos os cinco estudos que avaliaram esse parâmetro. A motilidade seminal melhorou significativamente em sete estudos. Não foi possível analisar o impacto da embolização com molas na densidade seminal.

Light-Mediated Seleno-Functionalization of Organic Molecules: Recent Advances.

Organoselenium compounds constitute an important class of substances with applications in the biological, medicinal and material sciences as well as in modern organic synthesis, attracting considerable attention from the scientific community. Therefore, the construction of the C-Se bond via facile, efficient and sustainable strategies to access complex scaffolds from simple substrates are an appealing and hot topic. Visible light can be regarded as an alternative source of energy and is associated with environmentally-friendly processes. Recently, the use of visible-light mediated seleno-functionalization has emerged as an ideal and powerful route to obtain high-value selenylated products, with diminished cost and waste. This approach, involving photo-excited substrates/catalyst and single-electron transfer (SET) between substrates in the presence of visible light has been successfully used in the versatile and direct insertion of organoselenium moieties in activated and unactivated C(sp3 )-H, C(sp2 )-H, C(sp)-H bonds as well as C-heteroatom bonds. In most cases, ease of operation and accessibility of the light source (LEDs or commercial CFL bulbs) makes this approach more attractive and sustainable than the traditional strategies.

Ultrasound-promoted regioselective synthesis of chalcogeno-indolizines by a stepwise 1,3-dipolar cycloaddition.

A series of new organochalcogen derivatives of indolizines was synthesized in moderate to excellent yields from pyridinium salts and chalcogeno-alkynes. The reaction can be carried out under thermal conditions or by sonochemical processes in short reaction times. The stepwise cycloaddition reaction forming chalcogeno-indolizines is regioselective and extends to a broad range of functional groups. Furthermore, novel chalcogeno-alkynes are reported and the first derivatives of teluro-indolizine are described. The influence of selenium functionalization on the photophysical properties of indolizines is also described, in which the compounds showed absorption in the UV-Vis region around 360 nm and emission in the blue-to-green region. Relatively low fluorescence quantum yield (ϕfl) values were calculated, in agreement with the chalcogen effect on other heterocycles.

Integrating environmental variables by multivariate ordination enables the reliable estimation of mineland rehabilitation status.

Despite the wide variety of variables commonly employed to measure the success of rehabilitation, the assessment and subsequent definition of indicators of environmental rehabilitation status are not simple tasks. The main challenges are comparing rehabilitated sites with target ecosystems as well as integrating individual environmental and eventually collinear variables into a single tractable measure for the state of a system before effective indicators that track rehabilitation may be modeled. Furthermore, a consensus is lacking regarding which and how many variables need to be surveyed for a reliable estimation of rehabilitation status. Here, we propose a multivariate ordination to integrate variables related to ecological processes, vegetation structure, and community diversity into a single estimation of rehabilitation status. As a case, we employed a curated set of 32 environmental variables retrieved from nonrevegetated, rehabilitating and reference sites associated with iron ore mines from the Urucum Massif, Mato Grosso do Sul, Brazil. By integrating this set of environmental variables into a single estimation of rehabilitation status, the proposed multivariate approach is straightforward and able to adequately address collinearity among variables. The proposed methodology allows for the identification of biases towards single variables, surveys or analyses, which is necessary to rank environmental variables regarding their importance to the assessment. Furthermore, we show that bootstrapping permitted the detection of the minimum number of environmental variables necessary to achieve reliable estimations of the rehabilitation status. Finally, we show that the proposed variable integration enables the definition of case-specific environmental indicators for more rapid assessments of mineland rehabilitation. Thus, the proposed multivariate ordination represents a powerful tool to facilitate the diagnosis of rehabilitating sites worldwide provided that sufficient environmental variables related to ecological processes, diversity and vegetation structure are gathered from nonrehabilitated, rehabilitating and reference study sites. By identifying deviations from predicted rehabilitation trajectories and providing assessments for environmental agencies, this proposed multivariate ordination increases the effectiveness of (mineland) rehabilitation.

Lysophosphatidylcholine triggers cell differentiation in the protozoan parasite Herpetomonas samuelpessoai through the CK2 pathway.

BACKGROUND: Protozoa are distantly related to vertebrates but present some features of higher eukaryotes, making them good model systems for studying the evolution of basic processes such as the cell cycle. Herpetomonas samuelpessoai is a trypanosomatid parasite isolated from the hemipteran insect Zelus leucogrammus. Lysophosphatidylcholine (LPC) is implicated in the transmission and establishment of Chagas disease, whose etiological agent is Trypanosoma cruzi. LPC is synthesized by T. cruzi and its vectors, the hemipteran Rhodnius prolixus and Triatoma infestans. Platelet-activating factor (PAF), a phospholipid with potent and diverse physiological and pathophysiological actions, is a powerful inducer of cell differentiation in Herpetomonas muscarum muscarum and T. cruzi. The enzyme phospholipase A2 (PLA2) catalyzes the hydrolysis of the 2-ester bond of 3-sn-phosphoglyceride, transforming phosphatidylcholine (PC) into LPC. METHODS: In this study, we evaluated cellular differentiation, PLA2 activity and protein kinase CK2 activity of H. samuelpessoai in the absence and in the presence of LPC and PAF. RESULTS: We demonstrate that both PC and LPC promoted a twofold increase in the cellular differentiation of H. samuelpessoai, through CK2, with a concomitant inhibition of its cell growth. Intrinsic PLA2 most likely directs this process by converting PC into LPC. CONCLUSIONS: Our results suggest that the actions of LPC on H. samuelpessoai occur upon binding to a putative PAF receptor and that the protein kinase CK2 plays a major role in this process. Cartoon depicting a model for the synthesis and functions of LPC in Herpetomonas samuelpessoai, based upon our results regarding the role of LPC on the cell biology of Trypanosoma cruzi [28-32]. N nucleus, k kinetoplast, PC phosphatidylcholine, LPC lysophosphatidylcholine, PLA2 phospholipase A2, PAFR putative PAF receptor in trypanosomatids [65], CK2 protein kinase CK2 [16].

Synthesis of Renewable Poly(limonene): A Kinetic Modeling Study to Improve the Polymerization

Abstract Despite its potential in the production of polymers from renewable sources, D-limonene faces difficulties in its polymerization, resulting in low monomer conversion and molar mass. In order to investigate the non-ideality inherent kinetics, this work explores different modeling strategies for D-limonene radical polymerization, using benzoyl peroxide as initiator. The starting model considered the classical approach for conventional radical polymerization. This model was then corrected by including reaction orders different from the unit. After an analysis and choice of the best model, computer simulations were compared with experimental results from literature, validating the chosen approach. It was found that the process is drastically influenced by chain transfer reactions, presenting a non-ideal behavior. Finally, an analysis of distinct reaction conditions provided information on monomer conversion, molar mass and polymer dispersity, which could guide future research in the synthesis optimization. Higher molar mass poly(limonene) were obtained by simultaneously reducing the monomer and initiator concentrations.