Effects of Prebiotic Therapy on Gastrointestinal Microbiome of Individuals with Different Inflammatory Conditions: A Systematic Review of Randomized Controlled Trials.

Prebiotics are substrates selectively utilized by host microorganisms conferring a health benefit. The effects of prebiotics on the gut microbiome of individuals with inflammatory processes need further investigations. The purpose of this study was to evaluate the effects of prebiotics on the gastrointestinal microbiome of individuals with some types of inflammatory conditions. Randomized controlled clinical trials (RCTs) evaluating the effects of different prebiotics on the gut microbiome were included. A systematic review of the literature including searches in PubMed/MEDLINE, EMBASE, Cochrane Library, Web of Science, and Scopus databases was performed until 23 March 2023. The risk of bias was assessed using the Cochrane Collaboration's criteria. Qualitative data was tabulated to facilitate comparisons and represented in the form of descriptive statistics and summary tables. Thirty trials, ranging from 12 to 135 patients, were included. The most commonly used prebiotic type was inulin-type fructans, and the treatment duration ranged from 1 to 36 weeks. The majority of the trials investigated the gut microbiome using 16 s rRNA gene sequencing on the Illumina Miseq platform. In general, prebiotic therapy exerted positive effects on inflammatory conditions. An increase in Bifidobacterium genus was the most common shift in bacterial composition observed. Within the limits of this systematic review, it can be suggested that prebiotic therapy presents the potential to favorably modulate the gastrointestinal microbiome of individuals with different types of inflammatory conditions.

Cellular consequences of small supernumerary marker chromosome derived from chromosome 12: mosaicism in daughter and father.

Constitutional genomic imbalances are known to cause malformations, disabilities, neurodevelopmental delay, and dysmorphia and can lead to dysfunctions in the cell cycle. In extremely rare genetic conditions such as small supernumerary marker chromosomes (sSMC), it is important to understand the cellular consequences of this extra marker, as well the factors that contribute to their maintenance or elimination through successive cell cycles and phenotypic impact. The study of chromosomal mosaicism provides a natural model to characterize the effect of aneuploidy on genome stability and compare cells with the same genetic background and environment exposure, but differing in the presence of sSMC. Here, we report the functional characterization of different cell lines from two familial patients with mosaic sSMC derived from chromosome 12. We performed studies of proliferation dynamics, stability, and variability of these cells using fluorescent in situ hybridization (FISH), sister chromatid exchanges (SCE), and conventional staining. We also quantified the telomere-related genomic instability of sSMC cells using 3D telomeric profile analysis by quantitative-FISH. sSMC cells exhibited differences in the cell cycle dynamics compared to normal cells. First, the sSMC cells exhibited lower proliferation index and higher frequency of SCE than normal cells, associated with a higher level of chromosomal instability. Second, sSMC cells exhibited more telomeric-related genomic instability. Lastly, the differences of sSMC cells distribution among tissues could explain different phenotypic repercussions observed in patients. These results will help in our understanding of the sSMC stability, maintenance during cell cycle, and the cell cycle variables involved in the different phenotypic manifestations.

Cellular consequences of small supernumerary marker chromosome derived from chromosome 12: mosaicism in daughter and father

Constitutional genomic imbalances are known to cause malformations, disabilities, neurodevelopmental delay, and dysmorphia and can lead to dysfunctions in the cell cycle. In extremely rare genetic conditions such as small supernumerary marker chromosomes (sSMC), it is important to understand the cellular consequences of this extra marker, as well the factors that contribute to their maintenance or elimination through successive cell cycles and phenotypic impact. The study of chromosomal mosaicism provides a natural model to characterize the effect of aneuploidy on genome stability and compare cells with the same genetic background and environment exposure, but differing in the presence of sSMC. Here, we report the functional characterization of different cell lines from two familial patients with mosaic sSMC derived from chromosome 12. We performed studies of proliferation dynamics, stability, and variability of these cells using fluorescent in situ hybridization (FISH), sister chromatid exchanges (SCE), and conventional staining. We also quantified the telomere-related genomic instability of sSMC cells using 3D telomeric profile analysis by quantitative-FISH. sSMC cells exhibited differences in the cell cycle dynamics compared to normal cells. First, the sSMC cells exhibited lower proliferation index and higher frequency of SCE than normal cells, associated with a higher level of chromosomal instability. Second, sSMC cells exhibited more telomeric-related genomic instability. Lastly, the differences of sSMC cells distribution among tissues could explain different phenotypic repercussions observed in patients. These results will help in our understanding of the sSMC stability, maintenance during cell cycle, and the cell cycle variables involved in the different phenotypic manifestations.

What is the preferred concentration of ethanolamine oleate for sclerotherapy of oral vascular anomalies?

BACKGROUND: This study compared three different concentrations of EO (1.25%, 2.5% and 5%) for the treatment of oral vascular anomalies (OVAs). MATERIAL AND METHODS: This was a retrospective comparative analysis of patients with OVAs treated with EO. Anomalies smaller than 20 mm were included. The patients were treated with 1.25% (G1), 2.5% (G2), and 5% (G3) and clinical data were obtained. The number of sessions, the final volume and dose of EO were statistically analyzed to verify effectiveness and safety of the treatment. The different concentrations of EO were compared considering the number of sessions, the final volume and total dose of EO. Analysis of covariance (ANCOVA) was used to evaluate the influence of covariates on the outcomes. A p-value < 0.05 was considered significant. RESULTS: Nineteen women and 11 men with a median age of 54 years were included. The OVAs were most frequent in the lip (n=14) and cheek (n=9). All lesions exhibited complete clinical healing within 28 days. Patients of G3 required fewer sessions than those of G2 (p=0.017), a lower final volume compared to the other groups (p<0.001), and a lower total dose than G1 (p<0.001). Patients of G1 used a lower total dose than G2 (p=0.003). CONCLUSIONS: The concentration of 5% EO performed better than 1.25% and 2.5% for sclerotherapy of OVAs measuring up to 20 mm. This preliminary result should be the preferred concentration of EO to provide an effective and safe treatment of OVAs.

Ventilation-induced changes correlate to pulmonary vascular response and VEGF, VEGFR-1/2, and eNOS expression in the rat model of postnatal hypoxia.

Neonatal asphyxia occurs due to reduction in oxygen supply to vital organs in the newborn. Rapid restoration of oxygen to the lungs after a long period of asphyxia can cause lung injury and decline of respiratory function, which result from the activity of molecules that induce vascular changes in the lung such as nitric oxide (NO) and vascular endothelial growth factors (VEGF). In this study, we evaluated the pulmonary and vascular morphometry of rats submitted to the model of neonatal asphyxia and mechanical ventilation, their expression of pulmonary VEGF, VEGF receptors (VEGFR-1/VEGFR-2), and endothelial NO synthase (eNOS). Neonate Sprague-Dawley rats (CEUA #043/2011) were divided into four groups (n=8 each): control (C), control submitted to ventilation (CV), hypoxia (H), and hypoxia submitted to ventilation (HV). The fetuses were harvested at 21.5 days of gestation. The morphometric variables measured were body weight (BW), total lung weight (TLW), left lung weight (LLW), and TLW/BW ratio. Pulmonary vascular measurements, VEGFR-1, VEGFR-2, VEGF, and eNOS immunohistochemistry were performed. The morphometric analysis showed decreased TLW and TLW/BW ratio in HV compared to C and H (P<0.005). Immunohistochemistry showed increased VEGFR-2/VEGF and decreased VEGFR-1 expression in H (P<0.05) and lower eNOS expression in H and HV. Median wall thickness was increased in H, and the expression of VEGFR-1, VEGFR-2, VEGF, and eNOS was altered, especially in neonates undergoing H and HV. These data suggested the occurrence of arteriolar wall changes mediated by NO and VEGF signaling in neonatal hypoxia.

Effectiveness and safety of foam sclerotherapy with 5% ethanolamine oleate in the treatment of low-flow venous malformations in the head and neck region: a case series.

The aim of this study was to evaluate the effectiveness and safety of 5% ethanolamine oleate (EO) foam in the treatment of low-flow venous malformations in the head and neck region. Seventeen consecutive patients (six male, 11 female) and 34 low-flow venous malformations were enrolled. The vascular anomalies ranged between 20mm and 80mm in size. The typical clinical indication was a swelling (88.2%) with a purple colour (85.3%); the most frequent location was the tongue (23.5%). Ethanolamine oleate foam was produced via the Tessari method and applied at 10mg per 1cm to the vascular anomalies. This process resulted in the highest clinical healing score in 64.7% of cases, and half of the patients reported a high level of satisfaction (score >9). In the majority of cases (88.2%), the patients reported that the pain immediately postoperative was mild or moderate. There were direct relationships between vascular anomaly size and the volume of EO applied, the number of sessions, and healing (P<0.05). No recurrence was observed during 6 months of follow-up. This case series showed the effectiveness and safety of 5% EO foam for the treatment of venous malformations in the head and neck region.

Tuberculosis among South American immigrants in São Paulo municipality: an analysis in space and time.

OBJECTIVE: To identify spatial and temporal, and spatial variation in temporal trends in clusters of tuberculosis (TB) among South American migrants residing in São Paulo municipality, SP, Brazil, between 2006 and 2013. DESIGN: An ecological descriptive study was conducted using data obtained from official TB reports and the 2010 Brazilian demographic census. Clusters were identified using scan statistics and SaTScan software; those with P < 0.05 were considered statistically significant. Social and economic characteristics of residents within the clusters were investigated. RESULTS: One high-risk spatial cluster (relative risk [RR] 4.46, P < 0.001) for TB was identified. Bolivian immigrants comprised the majority of immigrants residing in this area. One purely temporal high-risk cluster was identified between 2011 and 2013 (RR 1.55, P = 0.001). In one of the spatial variation in temporal trends clusters, the annual increase in TB incidence was 17.54% inside the cluster and 5.17% outside. CONCLUSIONS: We found areas of high risk for TB among South American immigrants. These areas and those with increasing trends of TB incidence must be prioritised by TB control programmes.

The last frontier: Coupling technological developments with scientific challenges to improve hazard assessment of deep-sea mining.

The growing economic interest in the exploitation of mineral resources on deep-ocean beds, including those in the vicinity of sensitive-rich habitats such as hydrothermal vents, raise a mounting concern about the damage that such actions might originate to these poorly-know ecosystems, which represent millions of years of evolution and adaptations to extreme environmental conditions. It has been suggested that mining may cause a major impact on vent ecosystems and other deep-sea areas. Yet, the scale and the nature of such impacts are unknown at present. Hence, building upon currently available scientific information it is crucial to develop new cost-effective technologies embedded into rigorous operating frameworks. The forward-thinking provided here will assist in the development of new technologies and tools to address the major challenges associated with deep sea-mining; technologies for in situ and ex situ observation and data acquisition, biogeochemical processes, hazard assessment of deep-sea mining to marine organisms and development of modeling tools in support of risk assessment scenarios. These technological developments are vital to validate a responsible and sustainable exploitation of the deep-sea mineral resources, based on the precautionary principle.

Ventilation-induced changes correlate to pulmonary vascular response and VEGF, VEGFR-1/2, and eNOS expression in the rat model of postnatal hypoxia

Neonatal asphyxia occurs due to reduction in oxygen supply to vital organs in the newborn. Rapid restoration of oxygen to the lungs after a long period of asphyxia can cause lung injury and decline of respiratory function, which result from the activity of molecules that induce vascular changes in the lung such as nitric oxide (NO) and vascular endothelial growth factors (VEGF). In this study, we evaluated the pulmonary and vascular morphometry of rats submitted to the model of neonatal asphyxia and mechanical ventilation, their expression of pulmonary VEGF, VEGF receptors (VEGFR-1/VEGFR-2), and endothelial NO synthase (eNOS). Neonate Sprague-Dawley rats (CEUA #043/2011) were divided into four groups (n=8 each): control (C), control submitted to ventilation (CV), hypoxia (H), and hypoxia submitted to ventilation (HV). The fetuses were harvested at 21.5 days of gestation. The morphometric variables measured were body weight (BW), total lung weight (TLW), left lung weight (LLW), and TLW/BW ratio. Pulmonary vascular measurements, VEGFR-1, VEGFR-2, VEGF, and eNOS immunohistochemistry were performed. The morphometric analysis showed decreased TLW and TLW/BW ratio in HV compared to C and H (P<0.005). Immunohistochemistry showed increased VEGFR-2/VEGF and decreased VEGFR-1 expression in H (P<0.05) and lower eNOS expression in H and HV. Median wall thickness was increased in H, and the expression of VEGFR-1, VEGFR-2, VEGF, and eNOS was altered, especially in neonates undergoing H and HV. These data suggested the occurrence of arteriolar wall changes mediated by NO and VEGF signaling in neonatal hypoxia.

Glucose solution is more effective in relieving pain in neonates than non-nutritive sucking: A randomized clinical trial.

BACKGROUND: Few studies have compared the analgesic effect of 25% glucose and non-nutritive sucking. We compared the analgesic effect of 25% glucose and non-nutritive sucking in newborns undergoing hepatitis B vaccination. Our hypothesis is that 25% glucose is more effective in relieving pain than non-nutritive sucking. METHODS: A randomized clinical trial with 78 healthy newborns was performed. Neonates were assigned randomly to receive 25% glucose (G25) and non-nutritive sucking (NNS). Pain was assessed using the Neonatal Infant Pain Scale (NIPS) before and during the immunization procedure. In addition, we evaluated various physiological parameters and crying time. RESULTS: Neonates who received 25% glucose registered lower NIPS scores than those from the NNS group [mean (SD), 3.3 (2.1) vs. 5.6 (1.6), p < 0.001]. The crying time was shorter among newborns in the G25 group than in the NNS and control groups. CONCLUSION: The use of 25% glucose before the vaccination procedure was more effective in relieving acute pain, with newborns in the G25 group registering scores two times lower on the NIPS scale. The clinical practice of administering 25% glucose is therefore a suggested nondrug measure for pain relief during painful procedures. SIGNIFICANCE: Neonates who received 25% glucose registered lower NIPS scores than those from the NNS group; the crying time was shorter among newborns in the G25 group than in the NNS and control groups; the use of 25% glucose before the vaccination procedure was more effective in relieving acute pain.

Raw sewage as breeding site to Aedes (Stegomyia) aegypti (Diptera, culicidae).

The selection of oviposition sites by females of Aedes (Stegomyia) aegypti is a key factor for the larval survival and egg dispersion and has a direct influence in vector control programs. In this study, we evaluated the aspects of reproductive physiology of Ae. aegypti mosquitoes tested in the presence of raw sewage. Ae. aegypti females were used in oviposition bioassays according to two methodologies: (i) choice assay, in which three oviposition substrates were offered in the same cage: treatment (raw sewage), positive control (distilled water) and negative control (1% sodium hypochlorite) and; (ii) no choice assay, in which only one substrate was available. The physicochemical and microbiological analysis of the raw sewage used in this study indicated virtually no levels of chlorine, low levels of dissolved oxygen and high levels of nitrogenous compounds as well as the presence of Escherichia coli and total fecal coliforms. After 72h of oviposition, the eggs were counted and there was no statistically significant difference (p>0.05) in the oviposition rate between raw sewage and positive control in both methodologies. In addition, females were dissected to evaluate egg-retention and also there were no appreciable differences in egg retention even when raw sewage was the only substrate offered. The data also showed that egg hatching and larvae development occurred normally in the raw sewage. Therefore, the present study suggests that Ae. aegypti can adapt to new sites and lay eggs in polluted water, such as the raw sewage. These findings are of particular importance for the control and surveillance programs against Ae. aegypti in countries where the conditions of poor infrastructure and lack of basic sanitation are still an issue.

Tratamento de efluentes de abatedouro de frangos por meio de reator UASB seguido de filtro anaeróbio / Treatment of waste water poultry slaughter house through UASB reactor followed by anaerobic filter

O Brasil é um dos maiores produtores de aves do mundo e se destaca na exportação de carne de frango, que tem papel relevante na economia do país. Como resultado do crescimento da indústria de processamento do frango, há também um significativo aumento na geração de efluentes. Uma alternativa interessante para o tratamento desses resíduos são os reatores anaeróbios. Este trabalho teve como objetivo avaliar o desempenho do sistema reator UASB-Filtro anaeróbio no tratamento de efluentes de abate de frangos. O estudo foi desenvolvido em um abatedouro avícola, situado na região metropolitana de Belo Horizonte, Minas Gerais. O sistema de tratamento foi composto por peneira estática, caixa de gordura, reator UASB e filtro anaeróbio. A vazão média diária de efluentes do abatedouro foi de 30m³/dia. A carga orgânica aplicada no reator UASB foi de 0,71kg DQO/m³.d. O monitoramento do sistema foi realizado por meio de análises físico-químicas do afluente e dos efluentes da caixa de gordura, reator UASB e filtro anaeróbio. Os parâmetros avaliados foram: temperatura, pH, demanda química de oxigênio (DQO), demanda bioquímica de oxigênio (DBO), sólidos suspensos totais (SST), e sólidos suspensos voláteis (SSV). Os valores efluentes médios encontrados para DBO, DQO e SST foram 106, 290 e 56mg/L, respectivamente. A eficiência de remoção do sistema para DBO variou de 83 a 99%, e para DQO de 50 a 98%. A eficiência de remoção média de SST e SSV foi de 92%. Conclui-se que o sistema reator UASB seguido de filtro anaeróbio apresentou alto desempenho na remoção de sólidos e carga orgânica. Dessa forma, esses reatores tornam-se uma alternativa viável para o tratamento de águas residuárias de frigoríficos, já que oferecem bons resultados de remoção de poluentes.

Brazil is one of the largest poultry producers in the world and stands out in exportation of chicken meat, which plays an important role in the economy. As a result of the growth of the poultry processing industry, there is also a significant increase in the generation of wastewater. An interesting alternative for the treatment of such wastes is anaerobic. This study aimed to evaluate the performance of the system UASB reactor-anaerobic filter on wastewater treatment of slaughtering chickens. The study was conducted in a poultry slaughterhouse located in the metropolitan region of Belo Horizonte, Minas Gerais. The treatment system was composed of static sieve, grease trap, UASB reactor and anaerobic filter. The daily average flow of effluent from the abattoir was 30m³/day. The organic load applied to the UASB reactor was 0.71kg COD/m³.d. The monitoring system was performed by means of physico-chemical analysis of the influent and effluent of fat, UASB reactor and anaerobic filter. The parameters evaluated were: temperature, pH, chemical oxygen demand (COD), biochemical oxygen demand (BOD), total suspended solids (SS) and volatile suspended solids (VSS). The mean values for effluent BOD, COD and SS were 106, 290 and 56mg/L, respectively. The removal efficiency of BOD to the system ranged 83-99% for COD and 50-98%. The average removal efficiency of SS and SSV were 92%. We conclude that the system UASB reactor followed by anaerobic filter showed high performance in removing solids and organic load. Thus, these reactors become a viable alternative for treating wastewater slaughterhouses, offering good results in removing pollutants.

Contemporary and historic factors influence differently genetic differentiation and diversity in a tropical palm.

Population genetics theory predicts loss in genetic variability because of drift and inbreeding in isolated plant populations; however, it has been argued that long-distance pollination and seed dispersal may be able to maintain gene flow, even in highly fragmented landscapes. We tested how historical effective population size, historical migration and contemporary landscape structure, such as forest cover, patch isolation and matrix resistance, affect genetic variability and differentiation of seedlings in a tropical palm (Euterpe edulis) in a human-modified rainforest. We sampled 16 sites within five landscapes in the Brazilian Atlantic forest and assessed genetic variability and differentiation using eight microsatellite loci. Using a model selection approach, none of the covariates explained the variation observed in inbreeding coefficients among populations. The variation in genetic diversity among sites was best explained by historical effective population size. Allelic richness was best explained by historical effective population size and matrix resistance, whereas genetic differentiation was explained by matrix resistance. Coalescence analysis revealed high historical migration between sites within landscapes and constant historical population sizes, showing that the genetic differentiation is most likely due to recent changes caused by habitat loss and fragmentation. Overall, recent landscape changes have a greater influence on among-population genetic variation than historical gene flow process. As immediate restoration actions in landscapes with low forest amount, the development of more permeable matrices to allow the movement of pollinators and seed dispersers may be an effective strategy to maintain microevolutionary processes.

Behavioural changes and muscle strength in Rattus norvegicus experimentally infected with Toxocara cati and T. canis.

Toxocara canis and Toxocara cati are nematode parasites in dogs and cats, respectively, transmitted by ingestion of embryonated eggs, transmammary and transplacental (T. canis) routes and paratenic host predation. Many parasites use mechanisms that change the behaviour of their hosts to ensure continued transmission. Several researchers have demonstrated behavioural changes in mouse models as paratenic hosts for T. canis. However, there have been no studies on behavioural changes in laboratory rats (Rattus norvegicus) experimentally infected with T. cati. This study investigated behavioural changes and muscle strength in male and female rats experimentally infected with T. cati or T. canis in acute and chronic phases of infection. Regardless of sex, rats infected with T. cati showed a greater decrease in muscle strength 42 days post infection compared to rats infected with T. canis. However, behavioural changes were only observed in female rats infected with T. canis.

Functional polymorphisms of interleukin-18 gene and risk of breast cancer in a Brazilian population.

Interleukin-18 (IL-18) is a key cytokine responsible for immune response and involved in the process of cancer development. In this case-control study, we tested whether IL-18 promoter polymorphism contributes to breast cancer susceptibility in Brazilian patients. The two groups studied were 154 patients with breast cancer and 118 healthy individuals. The frequency of IL-18 promoter single nucleotide polymorphisms (SNPs) at positions -607 (C/A) (rs1946518) and -137 (G/C) (rs187238) was determined by polymerase chain reaction analyses. The polymorphisms genotyped in this study showed a significant association with breast cancer under different genetic models. Both SNPs showed a positive association. For the IL18-607 polymorphism the best model was the codominant genetic model [CC vs AA, P = 0.004, odds ratio (OR) = 2.782, 95% confidence interval (CI) 1.385-5.589]. For IL18-137 statistical significance was found using the recessive genetic model (P = 0.008, OR = 3.896, 95% CI 1.427-10.639). The association between the haplotypes of the IL18 gene and breast cancer was further confirmed. Our results suggest that IL18-607 and IL18-137 polymorphism contributes to increase the breast cancer risk. To our knowledge, this is the first report regarding Brazilian breast cancer patients and IL18 promoter polymorphisms.

Tools for determining critical levels of atmospheric ammonia under the influence of multiple disturbances.

Critical levels (CLEs) of atmospheric ammonia based on biodiversity changes have been mostly calculated using small-scale single-source approaches, to avoid interference by other factors, which also influence biodiversity. Thus, it is questionable whether these CLEs are valid at larger spatial scales, in a multi- disturbances context. To test so, we sampled lichen diversity and ammonia at 80 sites across a region with a complex land-cover including industrial and urban areas. At a regional scale, confounding factors such as industrial pollutants prevailed, masking the CLEs. We propose and use a new tool to calculate CLEs by stratifying ammonia concentrations into classes, and focusing on the highest diversity values. Based on the significant correlations between ammonia and biodiversity, we found the CLE of ammonia for Mediterranean evergreen woodlands to be 0.69 µg m(-3), below the previously accepted value of 1.9 µg m(-3), and below the currently accepted pan-European CLE of 1.0 µg m(-3).

In vitro evaluation of the resistance of a 2.0-mm titanium fixation system in the sectioned angle without continuity of the inferior border of the mandible.

The aim of this in vitro study was to evaluate the mechanical resistance of a 2.0-mm titanium system applied to the mandibular angle, either with or without continuity of the inferior border of the mandible. Polyurethane mandibles were used as substrates and divided into two groups: unfavourable and favourable to treatment. A single cut was made through the retromolar region, simulating an angle fracture either unfavourable or favourable to treatment. In addition, a small fragment of the inferior border of the mandible was removed in some of the mandibles, creating a discontinuity. The fragments were stabilized in accordance with the technique of Champy et al. The substrates were adapted to a universal mechanical testing machine and submitted to a constant load applied at three different points; load values were obtained at three different moments of displacement: 1mm, 2mm, and fixation failure. The value of the tip dislocation at final displacement was obtained. When the load was applied at the first molars, regardless of the side, no statistically significant difference was observed between the groups. When the load was applied at the central incisors, a statistically significant difference was observed at fixation failure in the unfavourable to treatment group, with better results in the subgroup with continuity of the inferior border of the mandible compared to the subgroup without continuity. Discontinuity of the inferior border of the mandible did not decrease the mechanical resistance of the fixation.

The taxonomic distinctness of macroinvertebrate communities of Atlantic Forest streams cannot be predicted by landscape and climate variables, but traditional biodiversity indices can.

Predicting how anthropogenic activities may influence the various components of biodiversity is essential for finding ways to reduce diversity loss. This challenge involves: a) understanding how environmental factors influence diversity across different spatial scales, and b) developing ways to measure these relationships in a way that is fast, economical, and easy to communicate. In this study, we investigate whether landscape and bioclimatic variables could explain variation in biodiversity indices in macroinvertebrate communities from 39 Atlantic Forest streams. In addition to traditional diversity measures, i.e., species richness, abundance and Shannon index, we used a taxonomic distinctness index that measures the degree of phylogenetic relationship among taxa. The amount of variation in the diversity measures that was explained by environmental and spatial variables was estimated using variation partitioning based on multiple regression. Our study demonstrates that taxonomic distinctness does not respond in the same way as the traditional used in biodiversity studies. We found no evidence that taxonomic distinctness responds predictably to variation in landscape metrics, indicating the need for the incorporation of predictors at multiple scales in this type of study. The lack of congruence between taxonomic distinctness and other indices and its low predictability may be related to the fact that this measure expresses long-term evolutionary adaptation to ecosystem conditions, while the other traditional biodiversity metrics respond to short-term environmental changes.

Pressure effect on vibrational frequency and dephasing of 1-alkyl-3-methylimidazolium hexafluorophosphate ionic liquids.

Raman spectra in the range of the totally symmetric stretching mode of the [PF6](-) anion, νs(PF6), have been measured for 1-alkyl-3-methylimidazolium ionic liquids [CnC1im][PF6], for n = 4, 6, and 8, as a function of pressure at room temperature. The ionic liquids [C6C1im][PF6] and [C8C1im][PF6] remain in an amorphous phase up to 3.5 GPa, in contrast to [C4C1im][PF6], which crystallizes above ~0.5 GPa. Equations of state based either on a group contribution model or Carnahan-Starling-van der Waals model have been used to estimate the densities of the ionic liquids at high pressures. The shifts of the vibrational frequency of νs(PF6) with density observed in [C6C1im][PF6] and in [C8C1im][PF6] have been calculated by a hard-sphere model of a pseudo-diatomic solute under short-range repulsive interactions with the neighboring particles. The stochastic model of Kubo for vibrational dephasing has been used to obtain the amplitude of vibrational frequency fluctuation, <Δω(2)>, and the relaxation time of frequency fluctuation, τc, as a function of density by Raman band shape analysis of the νs(PF6) mode of [C6C1im][PF6] and [C8C1im][PF6].