Influence of pH shocks on trace netal dynamics and performance of methanol fed granular sludge bioreactors

The influence of pH shocks on the trace metal dynamics and performance of methanol fed upflow anaerobic granular sludge bed (UASB) reactors was investigated. For this purpose, two UASB reactors were operated with metal pre-loaded granular sludge (1mM Co, Ni and Fe; 30°C; 96h) at an organic loading rate (OLR) of 5gCOD l reactor-1d-1. One UASB reactor (R1) was inoculated with sludge that originated from a full scale reactor treating alcohol distillery wastewater, while the other reactor (R2) was inoculated with sludge from a full scale reactor treating paper mill wastewater. A 30h pH shock (pH 5) strongly affected the metal retention dynamics within the granular sludge bed in both reactors. Iron losses in soluble form with the effluent were considerable: 2.3 and 2.9% for R1 and R2, respectively, based on initial iron content in the reactors, while losses of cobalt and nickel in soluble form were limited. Sequential extraction of the metals from the sludge showed that cobalt, nickel, iron and sulfur were translocated from the residual to the organic/sulfide fraction during the pH shock in R2, increasing 34, 47, 109 and 41% in the organic/sulfide fraction, respectively. This is likely due to the modification of the iron sulfide precipitate stability, which influences the extractability of iron and trace metals. Such a translocation was not observed for the R1 sludge during the first 30h pH shock, but a second 4day pH shock induced significant losses of cobalt (18%), iron (29%) and sulfur (29%) from the organic/sulfide fraction, likely due to iron sulfide dissolution and concomitant release of cobalt. After the 30h pH shock, VFA accumulated in the R2 effluent, whereas both VFA and methanol accumulated in R1 after the 4day pH shock. The formed VFA, mainly acetate, were not converted to methane due to the loss of methanogenic activity of the sludge on acetate. The VFA accumulation gradually disappeared, which is likely to be related to out-competition of acetogens by methanogens. Zinc, copper and manganese supply did not have a clear effect on the acetate removal and methanol conversion, but zinc may have induced the onset of methanol degradation after day 152 in R1

Tomato protoplast DNA transformation: physical linkage and recombination of exogenous DNA sequences

Tomato protoplasts have been transformed with plasmid DNA's, containing a chimeric kanamycin resistance gene and putative tomato origins of replication. A calcium phosphate-DNA mediated transformation procedure was employed in combination with either polyethylene glycol or polyvinyl alcohol. There were no indications that the tomato DNA inserts conferred autonomous replication on the plasmids. Instead, Southern blot hybridization analysis of seven kanamycin resistant calli revealed the presence of at least one kanamycin resistance locus per transformant integrated in the tomato nuclear DNA. Generally one to three truncated plasmid copies were found integrated into the tomato nuclear DNA, often physically linked to each other. For one transformant we have been able to use the bacterial ampicillin resistance marker of the vector plasmid pUC9 to 'rescue' a recombinant plasmid from the tomato genome. Analysis of the foreign sequences included in the rescued plasmid showed that integration had occurred in a non-repetitive DNA region. Calf-thymus DNA, used as a carrier in transformation procedure, was found to be covalently linked to plasmid DNA sequences in the genomic DNA of one transformant. A model is presented describing the fate of exogenously added DNA during the transformation of a plant cell. The results are discussed in reference to the possibility of isolating DNA sequences responsible for autonomous replication in tomato.

Exploring the meaning in meaningful coincidences: an interpretative phenomenological analysis of synchronicity in therapy

Synchronicity experiences (SEs) are defined as psychologically meaningful connections between inner events (e.g. thought, dream or vision) and one or more external events occurring simultaneously or at a future point in time. There has been limited systematic research that has investigated the phenomenology of SEs in therapy. This study aimed to redress this by exploring the process and nature of such experiences from the perspective of the practitioner. Semi-structured face-to-face interviews were conducted with a purposive sample of nine practitioners who reported SEs in their therapeutic sessions (three counsellors, three psychologists and three psychotherapists), and focused on how participants make sense of their experiences of synchronicity in therapy. Interpretative phenomenological analysis was used to identify three superordinate themes: sense of connectedness, therapeutic process, and professional issues. Findings suggest that SEs can serve to strengthen the therapeutic relationship and are perceived as useful harbingers of information about the therapeutic process, as well as being a means of overcoming communication difficulties, as they are seen to provide insights into the client’s experiencing of themselves and others, regardless of whether or not the SE is acknowledged by the client or disclosed by the therapist

Stress and Mindfulness in Parkinson's Disease: Clinical Effects and Potential Underlying Mechanisms

Contains fulltext : 232519.pdf (Publisher’s version ) (Open Access)Patients with Parkinson's disease (PD) are very vulnerable to the negative effects of psychological distress: neuropsychiatric symptoms, such as anxiety and depression, are highly prevalent in PD; motor symptoms (such as tremor) typically worsen in stressful situations; and dopaminergic medication is less effective. Furthermore, animal studies of PD suggest that chronic stress may accelerate disease progression. Adequate self-management strategies are therefore essential to reduce the detrimental effects of chronic stress on PD. Mindfulness-based interventions encourage individuals to independently self-manage and adapt to the challenges created by their condition. In PD, emerging clinical evidence suggests that mindfulness-based interventions may reduce psychological distress and improve clinical symptoms, but insight into the underlying mechanisms is lacking. In this viewpoint, we provide a systematic overview of existing mindfulness trials in PD. Furthermore, we discuss the cerebral mechanisms involved in acute and chronic stress, and the impact of mindfulness-based interventions on these networks. In addition, we delineate a hypothetical mechanistic framework of how chronic stress may increase the susceptibility for neuropsychiatric symptoms in PD and may potentially even influence disease progression. We end with offering recommendations for future research. © 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society

Sorption of cobalt and nickel on anaerobic granular sludges: isotherms and sequential extraction

The objective of this study was to investigate the sorption capacity and the fractionation of sorbed nickel and cobalt onto anaerobic granular sludges. Two different anaerobic granular sludges (non-fed, pH = 7) were loaded with nickel and cobalt in. adsorption experiments (monometal and competitive conditions). The combination of sequential extraction with the sorption isotherm analysis allowed the assessment of the sorption capacity of individual fractions present in the anaerobic granular sludges. The operational fractionation of the sorbed heavy metals was determined using a modified Tessier sequential extraction procedure. The sorption characteristics of each extracted fraction (exchangeable, carbonates, organic matter/sulfides and residual fractions) fitted well to the Langmuir model. The organic matter/sulfides fraction showed the highest affinity for cobalt and nickel in both sludges investigated compared to the other operationally defined fractions. The presence of iron negatively affected cobalt and nickel accumulation in this organic matter/sulfides fraction. The trace metals-iron sulfide interactions are likely to be the key process in controlling the distribution of cobalt and nickel during sorption onto non-fed methanogenic granules due to the high affinity of iron sulfides towards the metals studied. (C) 2004 Elsevier Ltd. All rights reserved

Sorption of cobalt and nickel on anaerobic granular sludges: isotherms and sequential extraction

The objective of this study was to investigate the sorption capacity and the fractionation of sorbed nickel and cobalt onto anaerobic granular sludges. Two different anaerobic granular sludges (non-fed, pH = 7) were loaded with nickel and cobalt in. adsorption experiments (monometal and competitive conditions). The combination of sequential extraction with the sorption isotherm analysis allowed the assessment of the sorption capacity of individual fractions present in the anaerobic granular sludges. The operational fractionation of the sorbed heavy metals was determined using a modified Tessier sequential extraction procedure. The sorption characteristics of each extracted fraction (exchangeable, carbonates, organic matter/sulfides and residual fractions) fitted well to the Langmuir model. The organic matter/sulfides fraction showed the highest affinity for cobalt and nickel in both sludges investigated compared to the other operationally defined fractions. The presence of iron negatively affected cobalt and nickel accumulation in this organic matter/sulfides fraction. The trace metals-iron sulfide interactions are likely to be the key process in controlling the distribution of cobalt and nickel during sorption onto non-fed methanogenic granules due to the high affinity of iron sulfides towards the metals studied. (C) 2004 Elsevier Ltd. All rights reserved

Influence of pH shocks on trace netal dynamics and performance of methanol fed granular sludge bioreactors

The influence of pH shocks on the trace metal dynamics and performance of methanol fed upflow anaerobic granular sludge bed (UASB) reactors was investigated. For this purpose, two UASB reactors were operated with metal pre-loaded granular sludge (1mM Co, Ni and Fe; 30°C; 96h) at an organic loading rate (OLR) of 5gCOD l reactor-1d-1. One UASB reactor (R1) was inoculated with sludge that originated from a full scale reactor treating alcohol distillery wastewater, while the other reactor (R2) was inoculated with sludge from a full scale reactor treating paper mill wastewater. A 30h pH shock (pH 5) strongly affected the metal retention dynamics within the granular sludge bed in both reactors. Iron losses in soluble form with the effluent were considerable: 2.3 and 2.9% for R1 and R2, respectively, based on initial iron content in the reactors, while losses of cobalt and nickel in soluble form were limited. Sequential extraction of the metals from the sludge showed that cobalt, nickel, iron and sulfur were translocated from the residual to the organic/sulfide fraction during the pH shock in R2, increasing 34, 47, 109 and 41% in the organic/sulfide fraction, respectively. This is likely due to the modification of the iron sulfide precipitate stability, which influences the extractability of iron and trace metals. Such a translocation was not observed for the R1 sludge during the first 30h pH shock, but a second 4day pH shock induced significant losses of cobalt (18%), iron (29%) and sulfur (29%) from the organic/sulfide fraction, likely due to iron sulfide dissolution and concomitant release of cobalt. After the 30h pH shock, VFA accumulated in the R2 effluent, whereas both VFA and methanol accumulated in R1 after the 4day pH shock. The formed VFA, mainly acetate, were not converted to methane due to the loss of methanogenic activity of the sludge on acetate. The VFA accumulation gradually disappeared, which is likely to be related to out-competition of acetogens by methanogens. Zinc, copper and manganese supply did not have a clear effect on the acetate removal and methanol conversion, but zinc may have induced the onset of methanol degradation after day 152 in R1