The effects of cold working on sensitization and intergranular corrosion behavior of AISI 304 stainless steel

The effects of prior cold rolling of up to an 80 pct reduction in thickness on the sensitization-desensitization behavior of Type AISI 304 stainless steel and its susceptibility to intergranular corrosion have been studied by electrochemical potentiokinetic reactivation (EPR) and Strauss-test methods. The results indicate that the prior deformation accelerated the sensitization as compared to the undeformed stainless steel. The deformed Type 304 stainless steel experienced desensitization at higher temperatures and times, and it was found to be enhanced by increased cold deformation. This could be attributed to the increased long-range chromium diffusion, possibly brought on by increasing pipe diffusion and vacancies. The role of the deformation-induced martensite (DIM) and texture, introduced by uniaxial cold rolling, on the sensitization-desensitization kinetics has also been discussed. This study could not reveal any systematic relationship between texture and the degree of sensitization (DOS) obtained. The effect of DIM on DOS seems to be pronounced at 500 °C when the steel retained significant amounts of DIM; however, the retained DIM is insignificant at higher sensitization times and temperatures

Biased-corrected richness estimates for the Amazonian tree flora

Amazonian forests are extraordinarily diverse, but the estimated species richness is very much debated. Here, we apply an ensemble of parametric estimators and a novel technique that includes conspecific spatial aggregation to an extended database of forest plots with up-to-date taxonomy. We show that the species abundance distribution of Amazonia is best approximated by a logseries with aggregated individuals, where aggregation increases with rarity. By averaging several methods to estimate total richness, we confirm that over 15,000 tree species are expected to occur in Amazonia. We also show that using ten times the number of plots would result in an increase to just ~50% of those 15,000 estimated species. To get a more complete sample of all tree species, rigorous field campaigns may be needed but the number of trees in Amazonia will remain an estimate for years to come

Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates

This is the final version. Available on open access from Wiley via the DOI in this recordData availability statement: The percentages of dispersal modes per plot are included as Supporting Information (Table S7, based on 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests in Amazonia). The dispersal modes assigned to these 5433 species and morphospecies are also included as Supporting Information (Table S8).Aim: To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser-availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource-availability hypothesis). Time period: Tree-inventory plots established between 1934 and 2019. Major taxa studied: Trees with a diameter at breast height (DBH) ≥ 9.55 cm. Location: Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield. Methods: We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance-weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes. Results: Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra-firme forests (excluding podzols) compared to flooded forests. Main conclusions: The disperser-availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types.Colombian institution Departamento Administrativo de Ciencia, Tecnología e Innovación COLCIENCIASFaculty of Sciences, Universidad de los Ande

Consistent patterns of common species across tropical tree communities

Trees structure the Earth’s most biodiverse ecosystem, tropical forests. The vast number of tree species presents a formidable challenge to understanding these forests, including their response to environmental change, as very little is known about most tropical tree species. A focus on the common species may circumvent this challenge. Here we investigate abundance patterns of common tree species using inventory data on 1,003,805 trees with trunk diameters of at least 10 cm across 1,568 locations 1–6 in closed-canopy, structurally intact old-growth tropical forests in Africa, Amazonia and Southeast Asia. We estimate that 2.2%, 2.2% and 2.3% of species comprise 50% of the tropical trees in these regions, respectively. Extrapolating across all closed-canopy tropical forests, we estimate that just 1,053 species comprise half of Earth’s 800 billion tropical trees with trunk diameters of at least 10 cm. Despite differing biogeographic, climatic and anthropogenic histories 7, we find notably consistent patterns of common species and species abundance distributions across the continents. This suggests that fundamental mechanisms of tree community assembly may apply to all tropical forests. Resampling analyses show that the most common species are likely to belong to a manageable list of known species, enabling targeted efforts to understand their ecology. Although they do not detract from the importance of rare species, our results open new opportunities to understand the world’s most diverse forests, including modelling their response to environmental change, by focusing on the common species that constitute the majority of their trees

PÚRPURA TROMBOCITOPÊNICA TROMBÓTICA COM EVOLUÇÃO CLÍNICA ATÍPICA: RELATO DE CASO

Introdução: A Púrpura Trombocitopênica Trombótica (PTT) é uma doença rara, com incidência anual de 2 a 6 casos por milhão de habitantes, considerada uma emergência médica que, se não tratada, possui mortalidade de 90%. O reconhecimento da doença e o diagnóstico precoce são fundamentais para garantir maiores taxas de sobrevida na fase aguda. Objetivo: Relatar um caso de microangiopatia trombótica de evolução clínica atípica para PTT, com manifestações isquêmicas microcirculatórias ao longo de 4 anos, enfatizando os desafios diagnósticos. Relato de caso: Paciente feminina, 41 anos, apresentou eventos arteriais microcirculatórios de 2020 a 2024, incluindo déficits neurológicos agudos transitórios e síndrome coronariana aguda, sem obstrução arterial coronariana em cineangiocoronariografia. Em 2022, em contexto de suspeita de acidente vascular encefálico, houve a primeira identificação de anemia hemolítica (hemoglobina mínima de 8,8 g/dL) e plaquetopenia (50–60 mil/μL), tratada com prednisona 1 mg/kg/dia por suspeita de mecanismo autoimune, evoluindo com melhora das citopenias, mas permaneceu sem diagnóstico definitivo de microangiopatia trombótica. Entre 2022 a 2023, evidenciada creatinina em níveis estáveis de 1,3 a 1,4 mg/dL – taxa de filtração glomerular estimada por CKD-EPI de 53 mL/min/1.73 m²– sem alterações estruturais renais ou sedimento ativo. Em 2024, procurou atendimento com hipermenorreia com duração de 2 semanas precedendo confusão mental e hipoestesia súbita de membro superior direito, caráter flutuante, com evidência de anemia hemolítica (hemoglobina 8,5 g/dL, reticulócitos 102942 μL, DHL 520 U/L e haptoglobina < 7 mg/dL), plaquetopenia (18 mil/μL) e contagem de 5% de esquizócitos em sangue periférico. Realizado estudo de vasos em angiotomografia de crânio e pescoço, sem evidência de obstrução de grandes artérias. Após 2 semanas de internação, houve deterioração cognitiva e aumento vertiginoso de provas de hemólise (reticulócitos 225817 μL e DHL 1597 U/L), com troponina T alta sensibilidade 63 ng/L, favorecendo diagnóstico de PTT. A dosagem de ADAMTS-13 de 8% no 4º dia de plasmaferese contribui para confirmação diagnóstica. O tratamento com plasmaférese, prednisona 1 mg/kg/dia e rituximabe (dose fixa de 1000 mg em D1 e D15) resultou em recuperação clínica e hematológica. Discussão: Este caso destaca a importância de investigar manifestações de PTT que não seguem o curso agudo típico. O desenvolvimento de sinais e sintomas ao longo de quatro anos previamente ao diagnóstico é incomum e sugere a necessidade de estudos adicionais para compreender condições associadas e fatores subjacentes. Casos como este ampliam nosso conhecimento sobre a diversidade fenotípica da PTT e enfatizam a importância de um manejo contínuo e personalizado para melhorar o prognóstico dos pacientes. Conclusão: A abordagem investigativa ampliada foi crucial para a intervenção apropriada no caso, sublinhando a necessidade de um diagnóstico diferencial abrangente para variações clínicas de microangiopatia trombótica