Chemical Speciation of Copper in a Salt Marsh Estuary and Bioavailability to Thaumarchaeota

The concentrations of dissolved copper (Cud), copper-binding ligands, thiourea-type thiols, and humic substances (HSCu) were measured in estuarine waters adjacent to Sapelo Island, Georgia, USA, on a monthly basis from April to December 2014. Here we present the seasonal cycle of copper speciation within the estuary and compare it to the development of an annually occurring bloom of Ammonia Oxidizing Archaea (AOA), which require copper for many enzymes. Two types of complexing ligands (L1 and L2) were found to dominate with mean complex stabilities (log KCuL′) of 14.5 and 12.8. Strong complexation resulted in lowering the concentration of free cupric ion (Cu2+) to femtomolar (fM) levels throughout the study and to sub-fM levels during the summer months. A Thaumarchaeota bloom during this period suggests that this organism manages to grow at very low Cu2+ concentrations. Correlation of the concentration of the L1 ligand class with a thiourea-type thiol and the L2 ligand class with HSCu provide an interesting dimension to the identity of the ligand classes. Due to the stronger complex stability, 82–99% of the copper was bound to L1. Thiourea-type thiols typically form Cu(I) species, which would suggest that up to ~90% copper could be present as Cu(I) in this region. In view of the very low concentration of free copper (pCu > 15 at the onset and during the bloom) and a reputedly high requirement for copper, it is likely that the Thaumarchaeota are able to access thiol-bound copper directly

Toward a Regional Classification to Provide a More Inclusive Examination of the Ocean Biogeochemistry of Iron-Binding Ligands

Iron-binding ligands are paramount to understanding iron biogeochemistry and its potential to set the productivity and the magnitude of the biological pump in >30% of the ocean. However, the nature of these ligands is largely uncharacterized and little is known about their sources, sensitivity to photochemistry and biological transformation, or scavenging behavior. Despite many uncertainties, there is no doubt that ligands are produced by a wide range of biotic and abiotic processes, and that the bulk ligand pool encompasses a diverse range of molecules. Despite widespread recognition of the likelihood of a continuum of ligand classes making up the bulk ligand pool, studies to date largely focused on the dominant ligand. Thus, most studies have overlooked the need to assess where these targeted molecules fit across the spectrum of ligands that comprise the bulk ligand pool. Here we summarize present knowledge to critically assess the source(s), function(s), production pathways, and loss mechanisms of three important iron-binding organic ligand groups in order to assess their distinctive characteristics and how they link with observed ligand distributions. We considered that ligands are contained in broad groupings of exopolymer substances (EPS), humic substances (HS), and siderophores; using literature data for speciation modeling suggested that this adequately described the iron speciation reported in the ocean. We hypothesize that a holistic viewpoint of the multi-faceted controls on ligands dynamics is essential to begin to understand why some ligands can be expected to dominate in particular oceanic regions, depth strata, or exhibit seasonality and/or lateral gradients. We advocate that the development of a regional classification will enhance our understanding of the changing composition of the bulk ligand pool across the global ocean and to help address to what extent seasonality influences the makeup of this pool. This classification, based on selected functional ligand classes, can act as a bridge to use future ligand datasets to fill in the gaps in the continuum

From Nonstandard Analysis to various flavours of Computability Theory

As suggested by the title, it has recently become clear that theorems of Nonstandard Analysis (NSA) give rise to theorems in computability theory (no longer involving NSA). Now, the aforementioned discipline divides into classical and higher-order computability theory, where the former (resp. the latter) sub-discipline deals with objects of type zero and one (resp. of all types). The aforementioned results regarding NSA deal exclusively with the higher-order case; we show in this paper that theorems of NSA also give rise to theorems in classical computability theory by considering so-called textbook proofs.Comment: To appear in the proceedings of TAMC2017 (http://tamc2017.unibe.ch/

Adherence to Tuberculosis Therapy among Patients Receiving Home-Based Directly Observed Treatment: Evidence from the United Republic of Tanzania.

\ud \ud Non-adherence to tuberculosis (TB) treatment is the leading contributor to the selection of drug-resistant strains of Mycobacterium tuberculosis and subsequent treatment failure. Tanzania introduced a TB Patient Centred Treatment (PCT) approach which gives new TB patients the choice between home-based treatment supervised by a treatment supporter of their own choice, and health facility-based treatment observed by a medical professional. The aim of this study was to assess the extent and determinants of adherence to anti-TB therapy in patients opting for home-based treatment under the novel PCT approach. In this cross-sectional study, the primary outcome was the percentage of patients adherent to TB therapy as detected by the presence of isoniazid in urine (IsoScreen assay). The primary analysis followed a non-inferiority approach in which adherence could not be lower than 75%. Logistic regression was used to examine the influence of potentially predictive factors. A total of 651 new TB patients were included. Of these, 645 (99.1%) provided urine for testing and 617 patients (95.7%; 90%CI 94.3-96.9) showed a positive result. This result was statistically non-inferior to the postulated adherence level of 75% (p<0.001). Adherence to TB therapy under home-based Directly Observed Treatment can be ensured in programmatic settings. A reliable supply of medication and the careful selection of treatment supporters, who preferably live very close to the patient, are crucial success factors. Finally, we recommend a cohort study to assess the rate of adherence throughout the full course of TB treatment

Seksueel overdraagbare aandoeningen, waaronder HIV, in Nederland in 2007

Net als in 2006 was chlamydia in 2007 de meest gediagnosticeerde bacterikle geslachtsziekte in de soacentra, vooral bij jongeren. Het percentage positieve chlamydiatesten nder heteroseksuele mannen en vrouwen daalde enigszins, voor het eerst sinds vier jaar (van 10,6% naar 10,1%). In 2006 stabiliseerde dit percentage bij mannen die seks hebben met mannen (MSM), en die trend zette door in 2007. Het percentage positieve gonorroe-, syfilis- en hivtesten nam net als voorgaande jaren af in 2007 (respectievelijk 2,4%, 0,9% en ,5%). Deze infecties werden het meest gediagnosticeerd bij MSM. In 2007 zijn er 306 nieuwe hivdiagnoses gesteld in de soacentra, ongeveer een derde van de 864 hivpositieven die dat jaar landelijk in de hivcentra zijn gemeld. Eind 2007 waren in totaal 14.019 personen in Nederland met hiv geregistreerd. Het aandeel van MSM onder de nieuw hivinfecties nam in 2007 verder toe. Net als eerdere jaren werd in de soacentra bij MSM die bekend zijn met hun positieve hivstatus vaak nog een andere geslachtsziekte gevonden (45%). In deze groep is sinds 2004 regelmatig LGV, een agressieve variant van chlamydia, en sinds 2007 hepatitis C gediagnosticeerd. Versterkte surveillance en innovatieve interventies zijn nodig om verdere verspreiding onder MSM en naar andere groepen te voorkomen. Onder bepaalde migrantengroepen in Nederland (onder andere afkomstig uit Suriname, de Nederlandse Antillen en Aruba) komen hiv, chlamydia, gonorroe en syfilis relatief vaker voor dan onder autochtone Nederlanders. Ook deze constatering vraagt om vernieuwende maatregelen die op de bevolkingsgroepen zijn toegespitst. De soacentra bieden soazorg aan hoogrisicogroepen. In 2007 hebben ruim 78.000 personen zich daar laten testen, een toename van 13% ten opzichte van 2006. Net als in 2006 was chlamydia in 2007 de meest gediagnosticeerde bacterikle geslachtsziekte in de soacentra, vooral bij jongeren. Het percentage positieve chlamydiatesten onder heteroseksuele mannen en vrouwen daalde enigszins, voor het eerst sinds vier jaar (van 10,6% naar 10,1%). In 2006 stabiliseerde dit percentage bij mannen die seks hebben met mannen (MSM), en die trend zette door in 2007. Het percentage positieve gonorroe-, syfilis- en hivtesten nam net als voorgaande jaren af in 2007 (respectievelijk 2,4%, 0,9% en 0,5%). Deze infecties werden het meest gediagnosticeerd bij MSM.In 2007, chlamydia was the most common bacterial sexually transmitted infection (STI) diagnosed in Dutch STI centres. Similar to previous years, infections were reported especially in young heterosexuals. The proportion of positive chlamydia tests among heterosexual men and women decreased slightly for the first time in four years (from 10.6% to 10.1%). In 2006, this proportion had stabilized in men who have sex with men (MSM) with the trend continuing in 2007. The positivity rate for gonorrhoea (2.4%), syphilis (0.9%) and HIV (0.5%) continued to decrease in 2007. These infections were most frequently diagnosed in MSM. In 2007, 306 new positive HIV cases were diagnosed in STI centres in the Netherlands. This number amounts to about one third of the total number of 864 positive HIV cases registered nationally. At the end of 2007, a total of 14,019 HIV cases in care were registered in the Netherlands. The proportion of MSM among new HIV cases rose further in 2007. In line with previous years, concurrent STIs were diagnosed very frequently among MSM visiting STI centres (45%) who had known HIV positive status. In this group of men, Lymphogranuloma Venereum (LGV) an aggressive type of chlamydia, has been reported frequently since 2004; this has also been the case for hepatitis C since 2007. In this group of men, strengthened surveillance and innovative interventions are warranted in order to prevent further transmission both among MSM and to other population groups. In some specific migrant groups in the Dutch population -- for example, people from Surinam, the Netherlands Antilles and Aruba -- HIV, chlamydia, gonorrhoea and syphilis are more common than in the autochthonous Dutch population. This indicates the need for targeted intervention by risk profile. The specialised STI centres in the Netherlands offer STI testing and care targeted at high risk groups. In 2007, approximately 78,000 people used this service amounting to a rise of 13% compared to 2006

Chronic pain is common in mitochondrial disease

In the absence of cure, the main objectives in the management of patients with mitochondrial disease are symptom control and prevention of complications. While pain is a complicating symptom in many chronic diseases and is known to have a clear impact on quality of life, its prevalence and severity in people with genetically confirmed mitochondrial disease is unknown. We conducted a survey of pain symptoms in patients with genetically confirmed mitochondrial disease from two UK mitochondrial disease specialist centres. The majority (66.7%) of patients had chronic pain which was primarily of neuropathic nature. Presence of pain did not significantly impact overall quality of life. The m.3243A>G MTTL1 mutation was associated with higher overall pain severity and increased the likelihood of neuropathic pain compared to other causative nuclear and mitochondrial gene mutations. Although previously not considered a core symptom in people with mitochondrial disease, pain is a common clinical manifestation, frequently of neuropathic nature, and influenced by genotype. Given the impact on quality of life and treatment options available, pain-related symptoms should be carefully characterised and actively managed in this patient population

Periodic methanol masers: from a colliding wind binary (CWB) perspective

Since the discovery of periodic class II methanol masers at 6.7 and 12.2 GHz associated with high-mass star formation regions (HMSFRs), a number of possible driving mechanisms have been proposed to explain this phenomenon. Here, we apply a more realistic treatment of the original colliding wind binary (CWB) model explanation to investigate to what extent it can describe the flare profiles of the periodic methanol masers. It was found that the CWB hypothesis is feasible from an energetics standpoint, because the emission from the shocked gas does cause an outward shift of the position of the ionization front (IF). This confirms that the energy budget available from the shocked gas is enough to be the driving force behind the CWB model. The CWB model describes the light curve of the 1.25 km s−1 12.2 GHz velocity feature of G9.62 + 0.20E very well over 4000 d. The quiescent state flux density of the 1.25 km s−1 velocity feature can also be described very well by the time-dependent change in electron density (ne). The CWB model also describes the other periodic methanol masers, G22.357 + 0.066, G37.55 + 0.20, and G45.473 + 0.134, which have similar light curves, very well. This strongly suggests that these periodic methanol masers can be described by the time-dependent change in the free–free emission from some part of the background H II region against which the masers are projected

Comparison of spontaneous with controlled mode of ventilation in tonsillectomy

Methods: This randomized study compares spontaneous versus controlled ventilation in 60 ASA I and II patients undergoing tonsillectomy as regards haemodynamic stability, recovery characteristics, intra- and immediate postoperative complications and surgical impressions.Results: The patients in the balanced anaesthesia (B) group showed less haemodynamic variability compared to baseline after tracheal intubation, mouth gag application and removal and incision. Two patients had dysrhythmias in the B group compared to six in the spontaneous breathing (S) group. Six patients in the S group had a rise in endtidal carbon dioxide concentration above 7.8 kPa (60 mmHg). Recovery scores were higher in the B group at 10 and 20 min into recovery. The surgical impression of bleeding and jaw relaxation was similar with both groups. The incidence of postoperative nausea and vomiting and agitation was higher in the S group but did not achieve statistical significance.CONCLUSION: Use of balanced anaesthesia offered more haemodynamic stability and a rapid recovery