The effect of acidification on epilithic algae in the Loch Ard catchment.

A survey of epilithic filamentous algae was carried out at 15 sites on 10 streams with a range of mean pH from 4.37 to 6.67 in the Loch Ard area of the Trossachs, between 1986 and 1988. Monitoring of physical and chemical parameters was carried out in parallel. Photosynthetically Available Radiation (PAR) was measured using electronic integrators developed during the course of the study.Samples of epilithic algae were taken from natural and artificial substrates( microscope slides) to determine the relative contribution of different species to the community structure. Taxa could not be identified to species level in most cases, and are described by genus and cell diameter. Forty-nine taxa were distinguished in the filamentous algal communities found. Relative abundance of taxa was estimated. The mean value of abundance was calculated for use in subsequent statistical analyses. As an alternative, presence-absence(p/a) on each occasion was scored,a nd a mean value (pooled p/a) similarly calculated. Samples were taken also to determine algal biomass, as acetone or methanol extractable pigments (chlorophyll a and carotenoid) and ash-free dry weight (AFDW).The community structure at the different sites was investigated using statistical ecology computer programs. Using Inverse Association Analysis and Canonical Correspondence Analysis, distinct species assemblages were found in sites with mean pH values towards the extremes of the range encountered. Using Normal Association Analysis, Cluster Analysis and Canonical Correspondence Analysis, it was shown that sites are separable on the basis of the species they contain into groups related by mean pH. Using the results of Canonical Correspondence Analyses carried out by the program CANOCO (Ter Braak, 1988) on one half of the data set, field pH may be inferred from the species data, showing the indicator value of the community structure. In all analyses it was found that the pooled p/a data gave essentially the same result as the relative abundance data.The effects of changes in the pH and Aluminium content of water on the growth rate of selected species of green algaewas investigated using a laboratory-scale recirculating miniature artificial stream apparatus which allowed six variations to be tested at one time. Algae were grown attached to microscope slides. Growth rates were measured by counting cells in individual filaments over several successive time intervals. Mixed cultures of up to eight species were employed.Species characteristic of the lower-pH streams such as Hormidium subtile, Geminella 8?m. Stigeoclonium 5?m. and some species of Mougeotia have a pH optimum for growth rate between pH 4.5 and 5.5. Species characteristic of circumneutral streams, Draparnaldia sp. Stigeoclonium 8?m. and Oedogonaum species, have a pH optimum between pH 5.0 and 6.0 or above. Hormidium subtile and Geminella 8?m. can grow at a reduced rate in a monomeric Aluminium concentration of 200 ?g litre to the power -1 in which the majority of species tested are rapidly killed. Evidence was found for ecotypes with respect to pH in the genus Stigeoclonium.Biomass in natural waters was positively correlated with pH in contrast to some previous reports. In mixed cultures inthe laboratory, the maximum biomass developed was in the range pH 4.5 to 5.5. around the pH optimum of the speciespresent. At higher pH values (5.5 to 6.0) diatoms were predominant giving a brown-coloured periphyton layer whichis less visually obtrusive than the bright green growth of the filamentous chlorophytes. Therefore anecdotal reports ofan increased biomass upon acidification may reflect only a shift to more visible species. Inhibition of diatom growth byGermanium addition provided no evidence in favour of competition between diatoms and chlorophytes.Differences in community structure and changes in biomass with pH in laboratory culture cannot be ascribed to changesin invertebrate grazing or heterotrophic microbial activity. It is concluded therefore that - differences between speciesin tolerance towards pH or associated water chemistry variables are sufficient to explain differences in algal community structure in the field

Regulatory ecotoxicity testing of nanomaterials – proposed modifications of OECD test guidelines based on laboratory experience with silver and titanium dioxide nanoparticles

Conservation Biolog

International cancer microbiome consortium consensus statement on the role of the human microbiome in carcinogenesis

Objective In this consensus statement, an international panel of experts deliver their opinions on key questions regarding the contribution of the human microbiome to carcinogenesis.Design International experts in oncology and/or microbiome research were approached by personal communication to form a panel. A structured, iterative, methodology based around a 1-day roundtable discussion was employed to derive expert consensus on key questions in microbiome-oncology research.Results Some 18 experts convened for the roundtable discussion and five key questions were identified regarding: (1) the relevance of dysbiosis/an altered gut microbiome to carcinogenesis; (2) potential mechanisms of microbiota-induced carcinogenesis; (3) conceptual frameworks describing how the human microbiome may drive carcinogenesis; (4) causation versus association; and (5) future directions for research in the field.The panel considered that, despite mechanistic and supporting evidence from animal and human studies, there is currently no direct evidence that the human commensal microbiome is a key determinant in the aetiopathogenesis of cancer. The panel cited the lack of large longitudinal, cohort studies as a principal deciding factor and agreed that this should be a future research priority. However, while acknowledging gaps in the evidence, expert opinion was that the microbiome, alongside environmental factors and an epigenetically/genetically vulnerable host, represents one apex of a tripartite, multidirectional interactome that drives carcinogenesis.Conclusion Data from longitudinal cohort studies are needed to confirm the role of the human microbiome as a key driver in the aetiopathogenesis of cancer

A unified conceptual framework for metabolic phenotyping in diagnosis and prognosis

Understanding metabotype (multicomponent metabolic characteristics) variation can help generate new diagnostic and prognostic biomarkers and models with the potential to impact patient management. Here we present a suite of conceptual approaches for the generation, analysis and understanding of metabotypes from body fluids and tissues. We describe and exemplify four fundamental approaches to the generation and utilization of metabotype data via multiparametric measurement of: i) metabolite levels; ii) metabolic trajectories; iii) metabolic entropies and iv) metabolic networks and correlations in space and time. This conceptual framework can underpin metabotyping in the scenario of personalised medicine, with the aim of improving clinical outcomes for patients, but it will have value and utility in all areas of metabolic profiling well beyond this exemplar

Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

Three Rondolettos. For Pianoforte

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