56 research outputs found

    A new vanadium (III) complex of 2,6-Bis(3,5-diphenylpyrazol- 1-ylmethyl)pyridine as a catalyst for ethylene polymerization

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    The tridentate ligand 2,6-bis(3,5-diphenylpyrazol-1-ylmethyl)pyridine, abbreviated as 2,6-[(3,5-ph2pz-CH2)2-py], a new pyridine-pyrazole derivative, was prepared from 2,6-bis(bromomethyl)pyridine and 3,5-diphenylpyrazole. The ligand was characterized by means of elemental analyses, ATR-IR, 1H- and 13C-NMR spectroscopy and single crystal X-ray crystallography. Using this ligand, a new mononuclear vanadium (III) complex, {2,6-[(3,5-ph2pz)CH2]2py}VCl3 was prepared and characterized by elemental analysis, ATR-IR and HR-MS. The complex was investigated as a catalyst for ethylene polymerization and compared with 2,6-[(3,5-Me2pz)CH2]2py}VCl3 to explore the effect of the substituent on the pyrazolyl rings on ethylene polymerization. High catalytic activity was observed at ambient temperature. After treatment with AlEtCl2, these complexes showed high activity for ethylene polymerization converting ethylene to highly linear polyethylene and affording high molecular weight polymers (up to 1.0 × 106 g/mol) with unimodal molecular weight distributions

    Odour reduction strategies for biosolids produced from a Western Australian wastewater treatment plant: Results from Phase I laboratory trials

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    This study investigated sources of odours from biosolids produced from a Western Australian wastewater treatment plant and examined possible strategies for odour reduction, specifically chemical additions and reduction of centrifuge speed on a laboratory scale. To identify the odorous compounds and assess the effectiveness of the odour reduction measures trialled in this study, headspace solid-phase microextraction gas chromatography-mass spectrometry (HS SPME-GC-MS) methods were developed. The target odour compounds included volatile sulphur compounds (e.g. dimethyl sulphide, dimethyl disulphide and dimethyl trisulphide) and other volatile organic compounds (e.g. toluene, ethylbenzene, styrene, p-cresol, indole and skatole). In our laboratory trials, aluminium sulphate added to anaerobically digested sludge prior to dewatering offered the best odour reduction strategy amongst the options that were investigated, resulting in approximately 40% reduction in the maximum concentration of the total volatile organic sulphur compounds, relative to control

    Laboratory Scale Investigations of Potential Odour Reduction Strategies in Biosolids

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    This study investigated sources of odours from biosolids produced from a Western Australian wastewater treatment plant and examined potential odour reduction strategies on a laboratory scale. Odour reduction methods that were trialled included chemical additions and reduction of centrifuge speed. Chemical addition trials were conducted by adding alum, polyaluminium chloride or ferric chloride to digested sludge that had been sampled prior to the dewatering stage. Trials of chemical addition (alum) to plant dewatered cake were also undertaken. The impact of reducing centrifuge speed on biosolids odour was also investigated using a laboratory scale centrifuge calibrated to operate such that the shear forces on the sample would, as closely as possible, represent those on the plant. To identify the odorous compounds present in biosolids and to assess the effectiveness of the odour reduction measures, headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS SPME-GC-MS) methods were developed. Target odour compounds included volatile sulphur compounds (e.g. DMS, DMDS, DMTS) and other volatile organic compounds (toluene, thylbenzene, styrene, p-cresol, indole, skatole and geosmin). In our laboratory trials, aluminium sulphate added to digested sludge prior to dewatering offered the best odour reduction strategy among the options that were investigated, resulting in approximately 40% reduction in peak concentration of the total volatile organic sulphur compounds (TVOSC), relative to a control sample

    Evaluation of the antigen-experienced B-cell receptor repertoire in healthy children and adults

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    Upon antigen recognition via their B cell receptor (BR), B cells migrate to the germinal center where they undergo somatic hypermutation (SHM) to increase their affinity for the antigen, and class switch recombination (CSR) to change the effector function of the secreted antibodies. These steps are essential to create an antigen-experienced BR repertoire that efficiently protects the body against pathogens. At the same time, the BR repertoire should be selected to protect against responses to self-antigen or harmless antigens. Insights into the processes of SHM, selection, and CSR can be obtained by studying the antigen-experienced BR repertoire. Currently, a large reference data set of healthy children and adults, which ranges from neonates to the elderly, is not available. In this study, we analyzed the antigen-experienced repertoire of 38 healthy donors (HD), ranging from cord blood to 74 years old, by sequencing IGA and IGG transcripts using next generation sequencing. This resulted in a large, freely available reference data set containing 412,890 IGA and IGG transcripts. We used this data set to study mutation levels, SHM patterns, antigenic selection, and CSR from birth to elderly HD. Only small differences were observed in SHM patterns, while the mutation levels increase in early childhood and stabilize at 6 years of age at around 7%. Furthermore, comparison of the antigen-experienced repertoire with sequences from the naive immune repertoire showed that features associated with autoimmunity such as long CDR3 length and IGHV4-34 usage are reduced in the antigen-experienced repertoire. Moreover, IGA2 and IGG2 usage was increased in HD in higher age categories, while IGG1 usage was decreased. In addition, we studied clonal relationship in the different samples. Clonally related sequences were found with different subclasses. Interestingly, we found transcripts with the same CDR1-CDR3 sequence, but different subclasses. Together, these data suggest that a single antigen can provoke a B-cell response with BR of different subclasses and that, during the course of an immune response, some B cells change their isotype without acquiring additional SHM or can directly switch to different isotypes

    Imminent fall risk after fracture

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    Rationale: Adults with a recent fracture have a high imminent risk of a subsequent fracture. We hypothesise that, like subsequent fracture risk, fall risk is also highest immediately after a fracture. This study aims to assess if fall risk is time-dependent in subjects with a recent fracture compared to subjects without a fracture. Methods: This retrospective matched cohort study used data from the UK Clinical Practice Research Datalink GOLD. All subjects ≥50 years with a fracture between 1993 and 2015 were identified and matched one-to-one to fracture-free controls based on year of birth, sex and practice. The cumulative incidence and relative risk (RR) of a first fall was calculated at various time intervals, with mortality as competing risk. Subsequently, analyses were stratified according to age, sex and type of index fracture. Results: A total of 624,460 subjects were included; 312,230 subjects with an index fracture, matched to 312,230 fracture-free controls (71% females, mean age 70 ± 12, mean follow-up 6.5 ± 5 years). The RR of falls was highest in the first year after fracture compared to fracture-free controls; males had a 3-fold and females a 2-fold higher risk. This imminent fall risk was present in all age and fracture types and declined over time. A concurrent imminent fracture and mortality risk were confirmed. Conclusion/Discussion: This study demonstrates an imminent fall risk in the first years after a fracture in all age and fracture types. This underlines the need for early fall risk assessment and prevention strategies in 50+ adults with a recent fracture

    Exploring assessment of medical students\u27 competencies in pain medicine - A review

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    Introduction: Considering the continuing high prevalence and public health burden of pain, it is critical that medical students are equipped with competencies in the field of pain medicine. Robust assessment of student expertise is integral for effective implementation of competency-based medical education. Objective: The aim of this review was to describe the literature regarding methods for assessing pain medicine competencies in medical students. Method: PubMed, Medline, EMBASE, ERIC, and Google Scholar, and BEME data bases were searched for empirical studies primarily focusing on assessment of any domain of pain medicine competencies in medical students published between January 1997 and December 2016. Results: A total of 41 studies met the inclusion criteria. Most assessments were performed for low-stakes summative purposes and did not reflect contemporary theories of assessment. Assessments were predominantly undertaken using written tests or clinical simulation methods. The most common pain medicine education topics assessed were pain pharmacology and the management of cancer and low-back pain. Most studies focussed on assessment of cognitive levels of learning as opposed to more challenging domains of demonstrating skills and attitudes or developing and implementing pain management plans. Conclusion: This review highlights the need for more robust assessment tools that effectively measure the abilities of medical students to integrate pain-related competencies into clinical practice. A Pain Medicine Assessment Framework has been developed to encourage systematic planning of pain medicine assessment at medical schools internationally and to promote continuous multidimensional assessments in a variety of clinical contexts based on well-defined pain medicine competencies

    Multispecies Communities

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    Prof. Dr. Jens Schröter, Dr. Pablo Abend und Prof. Dr. Benjamin Beil sind Herausgeber der Reihe. Die Herausgeber*innen der einzelnen Hefte sind renommierte Wissenschaftler*innen aus dem In- und Ausland."Multispecies Communities" sind nicht mehr alleine auf den Menschen fixiert und bringen andere Akteure ins Spiel. Damit ergeben sich neue Formen der Kommunikationen und Kollaborationen, der Verantwortlichkeiten und der Rücksichtnahmen (awareness), der Vergemeinschaftungen und der Teilhaben: Diese finden statt zwischen Menschen und Tieren, Pflanzen und Algorithmen, Artefakten und Biofakten, Maschinen und Medien; zwischen den Sphären von belebt und unbelebt, real und virtuell, unberührt und augmentiert. Der Umgang mit Technik ist längst kein menschliches Privileg mehr, wie die Ausdifferenzierungen von Human-Computer Interaction (HCI) in Animal-Computer Interaction (ACI) oder Plant-Computer Interaction (PCI) verdeutlichen. Diese Ausdifferenzierungen finden ihren Niederschlag ebenso in den verschiedenen Disziplinen der Wissenschaft und in der Kunst sowie in gesellschaftlichen, sozialen, ethischen und politischen Aushandlungen des gemeinsamen Miteinanders. In dieser Ausgabe sind für diesen Diskussionszusammenhang relevante programmatische Texte versammelt und erstmals für den deutschsprachigen Raum zugänglich gemacht."Multispecies communities" are no longer focused on humans alone and bring other actors into play. This results in new forms of communication and collaboration, of responsibilities and awareness, of communalisation and participation: These take place between humans and animals, plants and algorithms, artefacts and biofacts, machines and media; between the spheres of animate and inanimate, real and virtual, untouched and augmented. Dealing with technology is no longer a human privilege, as the differentiations from Human-Computer Interaction (HCI) into Animal-Computer Interaction (ACI) or Plant-Computer Interaction (PCI) exemplify. These differentiations are also reflected in the various disciplines of science and art as well as in societal, social, ethical and political negotiations of shared interaction. In this issue, relevant programmatic texts have been collected for this discussion context and made available for the first time for the German-speaking area

    Repertoire sequencing of B cells elucidates the role of UNG and mismatch repair proteins in somatic hypermutation in humans

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    The generation of high-affinity antibodies depends on somatic hypermutation (SHM). SHM is initiated by the activation-induced cytidine deaminase (AID), which generates uracil (U) lesions in the B-cell receptor (BCR) encoding genes. Error-prone processing of U lesions creates a typical spectrum of point mutations during SHM. The aim of this study was to determine the molecular mechanism of SHM in humans; currently available knowledge is limited by the number of mutations analyzed per patient. We collected a unique cohort of 10 well-defined patients with bi-allelic mutations in genes involved in base excision repair (BER) (UNG) or mismatch repair (MMR) (MSH2, MSH6, or PMS2) and are the first to present next-generation sequencing (NGS) data of the BCR, allowing us to study SHM extensively in humans. Analysis using ARGalaxy revealed selective skewing of SHM mutation patterns specific for each genetic defect, which are in line with the five-pathway model of SHM that was recently proposed based on mice data. However, trans-species comparison revealed differences in the role of PMS2 and MSH2 in strand targeting between mice and man. In conclusion, our results indicate a role for UNG, MSH2, MSH6, and PMS2 in the generation of SHM in humans comparable to their function in mice. However, we observed differences in strand targeting between humans and mice, emphasizing the importance of studying molecular mechanisms in a human setting. The here developed method combining NGS and ARGalaxy analysis of BCR mutation data forms the basis for efficient SHM analyses of other immune deficiencies

    Implementation and evaluation of a multi-level mental health promotion intervention for the workplace (MENTUPP): study protocol for a cluster randomised controlled trial

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    Background Well-organised and managed workplaces can be a source of wellbeing. The construction, healthcare and information and communication technology sectors are characterised by work-related stressors (e.g. high workloads, tight deadlines) which are associated with poorer mental health and wellbeing. The MENTUPP intervention is a flexibly delivered, multi-level approach to supporting small- and medium-sized enterprises (SMEs) in creating mentally healthy workplaces. The online intervention is tailored to each sector and designed to support employees and leaders dealing with mental health difficulties (e.g. stress), clinical level anxiety and depression, and combatting mental health-related stigma. This paper presents the protocol for the cluster randomised controlled trial (cRCT) of the MENTUPP intervention in eight European countries and Australia. Methods Each intervention country will aim to recruit at least two SMEs in each of the three sectors. The design of the cRCT is based on the experiences of a pilot study and guided by a Theory of Change process that describes how the intervention is assumed to work. SMEs will be randomly assigned to the intervention or control conditions. The aim of the cRCT is to assess whether the MENTUPP intervention is effective in improving mental health and wellbeing (primary outcome) and reducing stigma, depression and suicidal behaviour (secondary outcome) in employees. The study will also involve a process and economic evaluation. Conclusions At present, there is no known multi-level, tailored, flexible and accessible workplace-based intervention for the prevention of non-clinical and clinical symptoms of depression, anxiety and burnout, and the promotion of mental wellbeing. The results of this study will provide a comprehensive overview of the implementation and effectiveness of such an intervention in a variety of contexts, languages and cultures leading to the overall goal of delivering an evidence-based intervention for mental health in the workplace
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