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The present study evaluated the effects of low salinity on the early larval development of Oreochromis niloticus, specifically histological damage to white muscle, morphology of the yolk-sac surface and trunk area, and molecular expression of apoptosis and cell proliferation biomarkers. Newly hatched larvae were submitted to four salinity treatments for a period of 48 or 72 h, in duplicate: (S0) freshwater, (S2) 2 g l−1, (S4) 4 g l−1, and (S6) 6 g l−1NaCl. Larval development was examined using histology, electron microscopy, enzyme-linked immunosorbent assay (ELISA), and morphometry. At the yolk-sac surface, larvae of S4 and S6 displayed alterations to the apical opening of chloride cells that may be related to osmotic expenditure caused by the increased salinity. Caspase-3 expression did not differ significantly among treatments, however significantly lower proliferating cell nuclear antigen (PCNA) expression (P < 0.05) suggested minor cell proliferation in larvae of S4 and S6 compared with S0 and S2. Furthermore, there was a significant reduction in both trunk area and percentage of normal white muscle fibres (WF) in larvae of S4 and S6. Vacuolated areas and myofibrils concentrated at the cell periphery and found in the white muscle from larvae exposed to saline environments suggested disturbance to muscle development. Oedema and mononuclear infiltrate were also observed in the white muscle of S4 and S6 larvae. Together these results indicated that treatments with 4 and 6 g l−1 NaCl may cause osmoregulation expenditure, morphological alterations to the yolk-sac surface and histological damage to skeletal muscle that negatively affected the early larval development of O. niloticus.
Resting state functional magnetic resonance imaging studies have identified functional connectivity patterns associated with acute undernutrition in anorexia nervosa (AN), but few have investigated recovered patients. Thus, a trait connectivity profile characteristic of the disorder remains elusive. Using state-of-the-art graph–theoretic methods in acute AN, the authors previously found abnormal global brain network architecture, possibly driven by local network alterations. To disentangle trait from starvation effects, the present study examines network organization in recovered patients.
Graph–theoretic metrics were used to assess resting-state network properties in a large sample of female patients recovered from AN (recAN, n = 55) compared with pairwise age-matched healthy controls (HC, n = 55).
Indicative of an altered global network structure, recAN showed increased assortativity and reduced global clustering as well as small-worldness compared with HC, while no group differences at an intermediate or local network level were evident. However, using support-vector classifier on local metrics, recAN and HC could be separated with an accuracy of 70.4%.
This pattern of results suggests that long-term recovered patients have an aberrant global brain network configuration, similar to acutely underweight patients. While the finding of increased assortativity may represent a trait marker of AN, the remaining findings could be seen as a scar following prolonged undernutrition.
The application of safeguards measures by the International Atomic Energy Agency (IAEA) involves analytical measurements of samples taken during inspections of nuclear facilities. Thus constant development and advancement of analytical techniques is required. For quality control purposes, the IAEA has implemented a dedicated project to enhance its analytical capabilities by producing tailor-made reference materials for the analysis of uranium isotope signatures in (single) particles.
To this end, a particle production set-up was developed and implemented at Forschungszentrum Juelich capable to produce uranium oxide microparticles which are intended to be used as (certified) reference materials for particle analysis methods. A step towards the certification process is the evaluation of consistency of the size distribution and homogeneity. A monodisperse particle size distribution as well as the single phase triuranium octoxide structure was confirmed using SEM, µ-XRD and µ-Raman spectroscopy, respectively. Analysis performed on single uranium oxide microparticles confirmed consistency of the uranium isotopic ratios in comparison to the initial precursor solutions. To improve the homogeneity and particle handling, the particles are transferred into suspensions, for which the stability was investigated with respect to dissolution.
Behaviours of concern (e.g. aggression) are often present in residents of long-term care (LTC) facilities diagnosed with dementia and may impact quality of life. Prior uncontrolled research has shown that an intervention involving sharing resident life histories may be effective in reducing aggressive behaviours and improving quality of life, perhaps by increasing staff empathy. We used a randomised controlled design, involving a considerably larger sample than previous investigations. We also examined staff perceptions of LTC resident personhood in relation to aggressive behaviour. Seventy-three residents were randomised to either a life history intervention (N = 38) or a control condition (N = 35). Ninety-nine nurses and care aides answered questionnaires about their own attitudes and the residents' behaviours and quality of life at baseline, post-intervention and at follow-up. Results of mixed-effects modelling indicated significant differences between groups in personhood perception and resident quality of life. Personhood perception mediated the relationship between the intervention and improved quality of life. We identified significant negative correlations between resident cognitive impairment and staff perceptions of resident personhood. Qualitative findings suggested that staff primarily changed their verbal interactions with residents following the intervention, which may be particularly helpful for residents with the most severe dementia. Our results indicate that LTC residents benefit when life histories are constructed with their families and shared with nursing staff.
We review and synthesize multiple biotic and abiotic proxies for marine nutrient and food availability, primary productivity, and food quality (stoichiometry) and propose what their relationships may have been to macroevolutionary processes, especially speciation. This review confirms earlier suggestions that there has been an overall increase in marine primary productivity over the Phanerozoic, but indicates that the increase has been irregular and that present levels may not be the peak. We integrate these indicators into a new estimate of relative primary productivity in the global ocean through the Phanerozoic. We then combine multiple, frequently conflicting ecological-evolutionary hypotheses into a general model for how primary production may affect speciation over geological time scales. This model, an elaboration and extension of the “speciation cycle” previously proposed by Grant and Grant, attempts to explain why an increase in food supply sometimes is associated with decreased diversity, and at other times with increased diversification. We propose some simple tests for the application of this model to the fossil record.
The formal commissioning of the IRWG occurred at the 1991 Buenos Aires General Assembly, following a Joint Commission meeting at the IAU GA in Baltimore in 1988 that identified the problems with ground-based infrared photometry. The meeting justification, papers, and conclusions, can be found in Milone (1989). In summary, the challenges involved how to explain the failure to achieve the milli-magnitude precision expected of infrared photometry and an apparent 3% limit on system transformability. The proposed solution was to redefine the broadband Johnson system, the passbands of which had proven so unsatisfactory that over time effectively different systems proliferated, although bearing the same “JHKLMNQ” designations; the new system needed to be better positioned and centered in the spectral windows of the Earth's atmosphere, and the variable water vapour content of the atmosphere needed to be measured in real time to better correct for atmospheric extinction.
We present new results in modeling the interiors of Giant Planets (GP) and Brown Dwarfs (BD). In general models of the interior rely on equation of state data for planetary materials which have considerable uncertainties in the high-pressure domain. Our calculations are based on ab initio equation of state (EOS) data for hydrogen, helium, hydrogen-helium mixtures and water as the representative of all heavier elements or ices using finite-temperature density functional theory molecular dynamics (FT-DFT-MD) simulations. We compare results for the BD Gliese 229B calculated with Saumon-Chabrier-Van Horn EOS (SCVH95) and our EOS data.
Archaeology, consistently warned off religion by wise old heads, here rushes deeper into the thicket to tackle the thorny topic of ancient witchcraft. The occasion was a seminar at Harvard organised by Stephen Mitchell and Neil Price to mark the twentieth anniversary of Carlo Ginzburg's influential book on the connections between witches and shamanism – and by implication the possible connections with prehistoric ritual and belief. Archaeology was by no means the only voice at the meeting, which was attended by scholars active in history, literature, divinity and anthropology. The discussions revealed much that was entangled in the modern psyche: ‘don't let's tame strangeness’ was one leitmotiv of this stimulating colloquium. A romantic attachment to the irrational is a feature of our time, especially among academics. But maybe taming strangeness is an archaeologist's real job…
The formal origin of the IRWG occured at the Buenos Aires General Assembly, following a Joint Commission meeting at the IAU GA in Baltimore in 1988 that identified the problems with ground-based infrared photometry. The situation is summarized in Milone (1989). In short, the challenges involved how to explain the failure to achieve the milli-magnitude precision expected of infrared photometry and an apparent 3% limit on system transformability. The proposed solution was to redefine the broadband Johnson system, the passbands of which had proven so unsatisfactory that over time effectively different systems proliferated, although bearing the same JHKLMNQ designations; the new system needed to be better positioned and centered in the atmospheric windows of the Earth's atmosphere, and the variable water vapour content of the atmosphere needed to be measured in real time to better correct for atmospheric extinction.
HbC (HBB glu6lys), along with HbS (HBB glu6val) and HbE (HBB glu26lys), is one of the three most common hemoglobin variants in humankind. Its positive charge that allows it to bind the erythrocyte membrane, and perhaps other unique features of this variant, lead to loss of cell K+ and water, thereby increasing erythrocyte density. HbC disease, defined as homozygosity for the HbC gene, causes mild hemolytic anemia; simple heterozygosity for HbC (HbC trait, HbAC) is innocuous. In HbSC disease, in which the erythrocyte concentration of HbS and HbC is nearly equal, the dehydrated, dense erythrocyte accentuates the deleterious properties of HbS by producing a milieu favoring HbS polymerization. HbSC disease causes vasoocclusive disease and hemolytic anemia, albeit on average both less severe than found in sickle cell anemia (homozygosity for HbS). Like sickle cell anemia, the hematological and clinical features of HbSC disease are heterogeneous, but all of the complications that make sickle cell anemia notorious can be present; some even appear more often in HbSC disease.
HbC and HbC Disease
Origins, Selection, and Distribution of HbC
HbC, the second hemoglobin variant discovered, was described in 1950, and the first homozygous case was reported in 1953. The βC-globin gene contains a GAG→AAG transition and codes for lysine instead of glutamic acid. Shortly after its description in African Americans, HbC was found to be common in Africa.
Mutations of hemoglobin can be polymorphic (>1% of a population), like HbS, HbE, HbC, and the thalassemias, or rare. Our first edition listed 750 unique hemoglobin variants; this number is now more than 1,000. In this chapter we address rare mutations. Some are associated with clinical disease; others are interesting solely for the biological principles they illustrate. A current listing of variant human hemoglobins is maintained in the HbVar database at http://globin.cse.psu.edu/, and the journal Hemoglobin (Taylor & Francis, Philadelphia) is a rich source for reports of new variants. Both are invaluable resources for clinicians and investigators with interests in unusual hemoglobin disorders.
Globin gene mutations, which include nearly every class of mutation so far described, except trinucleotide repeats and other nucleotide expansions associated with neuromuscular disorders, provided an early catalog of the mutations that can cause genetic disease. Clinically important but rare mutants affect hemoglobin stability causing premature red cell destruction; interfere with normal oxygen binding kinetics producing erythrocytosis; and permit heme iron oxidation, causing cyanosis. Most rare variants have no phenotype and are of biological and diagnostic interest only.
Comparatively few globin residues are critical for maintaining the structural integrity and functional performance of the molecule (Chapter 6). Hemoglobin gene mutations are, as a rule, not associated with hematological or clinical abnormalities and escape detection, especially when they are chromatographically silent.
Large-scale population screening programs have defined the worldwide prevalence of medically important hemoglobinopathies and thalassemias.
During development, humans express six different hemoglobin types, the products of eight different globin genes (Fig. 3.1, Chapter 3). Hb Gower I (ς2ε2), Gower II (α2ε2), and Portland (ς2γ2) are found in the embryo, fetal hemoglobin (HbF; α2γ2) is present mainly in the fetus but also in the embryo and adult, whereas HbA (α2β2) and HbA2 (α2δ2) are seen primarily in adults. All hemoglobins undergo posttranslational modifications forming minor hemoglobins. Globin genes are discussed in Chapter 3, hemoglobin switching in Chapter 5, and the structure and function of hemoglobin in Chapter 6 and. In this chapter we discuss the clinical and physiological attributes of HbF, HbA2, embryonic hemoglobins, and their posttranslational modifications.
The observation that hemoglobin in newborns' erythrocytes was resistant to alkaline denaturation provided the first suggestion that a hemoglobin existed that differed from normal HbA.
Structure of the γ-Globin Genes and γ-Globin
γ-Globin chains differ from β-globin chains in either 39 or 40 amino acid residues, depending on whether a glycine or alanine residue is present at γ136. γ-Globin is the product of two nearly identical γ-globin genes. A glycine codon is present in the 5′ or Gγ gene (HBG2) and an alanine codon characterizes the 3′, or Aγ gene (HBG1). Also, a common polymorphism is found in the Aγ gene, where threonine (AγT) replaces isoleucine (AγI) at codon γ75 (HbF-Sardinia). This striking similarity in protein sequence and structure of the γ-globin genes reflect their concerted evolution from gene duplication and gene conversion.