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Synthesis and structural characterization of methylindium imino/aminophenolates: Comparison to aluminum analogues and reactivity toward the coupling reactions of carbon dioxide with epoxides
Get PDFWe have synthesized methylindium complexes containing a variety of amino- and iminophenolate ligands for structural comparison to their aluminum analogues. The reaction of Me3In with the corresponding amino-/iminophenols resulted in the formation of MeIn(Et2NCH2CH2-abp) (1), MeIn(PyCH2-abp) (2), [MeIn(iPr-abp)]2 (3), MeIn(Ph-salen) (4), MeIn(Et-salan) (5), MeIn(Cy-ip) (6) and MeIn(Mes-ip) (7) [H2(Et2NCH2CH2-abp) = Et2NCH2CH2N(2-OH-3,5-C6H2tBu2)2, H2(PyCH2-abp) = (2-C5H4N)CH2N(2-OH-3,5-C6H2tBu2)2, H2(iPr-abp) = (CH3)2CHN(2-OH-3,5-C6H2tBu2)2, H2(Ph-salen) = 1,2-(NCH-2-OH-3,5-C6H2tBu2)2C6H4, H2(Et-salan) = 1,2-(NMeCH2-2-OH-3,5-C6H2tBu2)2C2H4, H(Cy-ip) = (2-OH-3,5-tBu2-C6H2)CHN(C6H11), and H(Mes-ip) = (2-OH-3,5-tBu2-C6H2CHN(2,4,6-Me3C6H2)]. X-ray crystallography studies show monomeric structures and five-coordinate indium centres for 1 and 2, a dimeric structure via intermolecular In…O interactions and five-coordinate indium centres for 3, and monomeric structures and fourcoordinate indium centres for 6 and 7. DFT calculations were used to rationalize the observed dimeric structure of 3 and monomeric structures of 6 and 7, and gauge the effect of ligand steric bulk and atomic radius in indium versus aluminum on dimerization. Compounds 2 and 5 are active catalysts for coupling reactions of carbon dioxide and propylene oxide to yield propylene carbonate and carbon dioxide with cyclohexene oxide to yield polycyclohexene carbonate. This work provides insight into controlling intermolecular bonding and hence reactivity in indium and aluminum amino-/iminophenolate complexes, and represent one of the first examples of indium complexes as catalysts for the formation of cyclic- or polycarbonates from carbon dioxide and epoxides.type of work: research articlepublication status: pre-prin
Cannabis and self-regulation
Get PDFCannabis is one of the most used recreational substances, especially among adolescents and young adults. Two studies examined the relationship between cannabis use and self-regulation among undergraduates. The first study (N = 248), an online survey, found that cannabis, alcohol, and cigarette use were related to lower levels of self-regulation. Among these substances, multiple regression analyses showed that cannabis use uniquely predicted lower levels of self-control and executive functioning when controlling for impression management. The second study (N = 31) compared regular cannabis users (n = 11) to nonusers (n = 15) on self-regulation performance following an ego depletion task. The depletion manipulation task required participants to choose between many everyday products, recreational substances, and occupations. To ensure the depletion task was effective, depleted nonusers (n = 15) were compared to a control group of nonusers (n = 5). The ego depletion manipulation was unsuccessful. Cannabis users did, however, perform worse on the Stroop task and a handgrip endurance task. Additionally, reported self-control from study one did not predict performance on these tasks at study two when controlling for cannabis use. The findings demonstrate that cannabis use is uniquely linked to lower levels of self-control, however, the causal order of this relationship remains unclear. The failure to replicate the ego depletion effect is discussed
Investigating aspartame and acesulfame potassium as potential novel ligands for Class A orphan GPCRs
Get PDFArtificial sweeteners are gaining increasing popularity as an alternative to sugar; however, new studies in rats show that prolonged exposer to artificial sweeteners increases breast, brain, and urinary cancer risk. Concerns have been raised with the quality, safety and the long-term health risks associated with artificial sweeteners and artificial sweeteners have been shown to induce metabolic syndrome. These sweeteners have demonstrated activity that is mediated via G-protein coupled receptors (GPCRs). GPCRs mediate many of our physiological responses to stimulants; however, around 100 of these receptors are deemed orphan, and may represent targets for sweetener activation. In this study, a high throughput screening platform was used to simultaneously quantify β-arrestin recruitment to 72 orphan GPCRs. Cells expressing receptors of interest were treated with the artificial sweeteners, aspartame and acesulfame K prior to quantification of receptor activation. GPR32, GPR4, GPR12, GPR84 and MAS1 were significantly activated in response to sweetener treatment. These receptors are expressed in epithelial cells. GPR4, GPR32, and GPR84 are connected to inflammatory responses, with artificial sweeteners also causing inflammation in the body. If validated, they will represent some of the first known ligands for the orphan receptors in question and could have implications for their role in inflammatory responses
Reactive oxygen production and scavenging in marine phytoplankton
Get PDFPhytoplankton are unicellular photosynthetic microorganisms adapted to live in open water. They use reactive oxygen species (ROS) for cell to cell signalling, although biotic or abiotically produced ROS can be harmful in higher concentrations and therefore phytoplankton must maintain ROS homeostasis. The Black Queen Hypothesis suggests that loss of function mutations carry on until the cost outweighs the benefit [1]. As it is harder for larger phytoplankton to get rid of ROS as it does not readily diffuse out of the cell, we investigated whether they would have more ROS detoxification genes, and fewer ROS producing genes. We indeed found a breakpoint at 3μm above which cells carry more genes encoding ROS scavenging. We could not determine whether there is an effect of cell size on the total genetic capacity for ROS production. The number of genes associated with ROS production and scavenging increased with larger genome size, although the slope was smaller than that of gene model size vs. genome size, indicating that less of the genome is allocated to ROS production and scavenging in larger genomes
Voices of Miramichi first-line workers: A qualitative study of the psychosocial needs and services for youth with disruptive behavious (YDB)
Get PDFYouth with disruptive behaviour (YDB) may have serious conditions such as conduct disorder (CD) or oppositional defiant disorder (ODD), which are often comorbid with clinical depression and substance abuse (Angold, Costello, & Erkanli, 1999; Rodgers et al., 2015). Thus, it may be challenging to professionally care for them and/or their families. Focusing on the city of Miramichi (New Brunswick) first-line workers [i.e., police officers and youth workers, including social workers and independent living program (ILP) coaches], this study investigated: (1) their perceptions of the psychosocial needs of YDB; (2) the potential barriers and facilitators in their daily work; and (3) awareness of existing NB services for YDB. This study used qualitative, semi-structured, telephone interviews with eight first-line workers. Data was analyzed using thematic analysis (Braun & Clarke, 2006). The analysis was divided into five general categories: general youth needs, risk and protective factors for youth, barriers for first-line workers in daily work with YDB, facilitators of daily work for first-line workers om daily work with YDB, and front-line workers’ awareness of services in NB. First, the investigation of youth needs in general generated five key themes: (1) lack of achievement and employment, (2) harmful behaviours, (3) mental health and drug abuse, (4) negative relationships, and (5) varying outcomes for YDB. Second, data related to risk factors and protective factors for these youth generated three main themes: (1) prosocial relationships and stable home life (2) sufficient services (3) completion of school and attainment of a job. Such results were consistent with the literature on youth disruptive behaviour disorders (YD). Third, five major themes presented in the data reflecting barriers in the daily work of first-line workers’: (1) The individual youth (2) the emotional nature of the job (3) insufficient services for youth (4) other individuals in the lives of youth (5) minimal barriers among police. Next, the most prominent facilitators in their daily work consisted of: (1) support for youth and (2) support for workers. Finally, when examining Miramichi first-line workers’ awareness of existing NB services, two themes emerged: (1) greater knowledge with greater experience and (2) exclusive awareness of Navicare/SoinsNavi by youth workers. This research indicates gaps in existing services and service delivery for youth within the city of Miramichi
GPR17 and GPR52 are activated by the artificial sweeteners sucralose and saccharin
Get PDFG-protein coupled receptors (GPCRs) are a class of transmembrane proteins which are responsible for communication and signalling in a wide variety of cell-cell and cell-environment interactions. They are responsible for senses including smell, sight and taste, in addition to internal metabolite sensing. GPCRs are excellent drug targets due to the important role they play in a variety of physiological processes; over 34% of all FDA approved drugs target GPCRs. Orphan GPCRs are a subset of approximately 90 GPCRs which do not have an established endogenous or exogenous ligand. Artificial sweeteners are a family of organic compounds which activate the GPCR taste receptor (T1R2/T1R3) but are not metabolized by the human body leading to the initial belief that they are safe and effective sugar replacements which reduce caloric consumption. However, recent findings suggest that chronic artificial sweetener consumption may lead to glucose intolerance and metabolic disease and that unknown receptors beyond T1R2/T1R3 are capable of sensing sweet molecules. In this study, 72 family A orphan GPCRs were screened for activation through treatment with a combination of the artificial sweeteners sucralose and saccharin using the PRESTO-Tango resource for GPCR interrogation. The strength of activation in identified receptor candidates was investigated further with both natural and artificial sweeteners. Two receptors were found to be significantly activated by the artificial sweeteners, GPR17 and GPR52, which is the first report of this receptor-agonist pairing. Dose response curves revealed that artificial sweetener activated GPR17 signalling was saturated at a concentration of 2 mM with a 1.5-fold change response for saccharin and a 1.6-fold change response for sucralose relative to control. GPR17 activation was higher for the sucrose treatment with a fold change of 2.1. Conversely, GPR52 responded more strongly to artificial sweeteners with a greater than 5-fold change in receptor activation when treated by sucralose or saccharin but was not activated by sucrose. These findings suggest that these orphan receptors may play a wider role in human metabolism than has been previously considered
A retrospective cohort study of Lyme disease patient outcomes
Get PDFLyme disease is a vector-borne illness caused by Borrelia spp. bacterium and spread primarily through the bite of a tick to humans and other mammalian hosts. Despite being a common disease prevalent in many regions of the world, there remains a considerable amount of uncertainty surrounding many aspects of the disease and consensus on the most appropriate and effective means of treating the illness remains to be achieved. Recommendations published by the Infectious Diseases Society of America (IDSA) and the International Lyme and Associated Diseases Society (ILADS), which are the primary guidelines followed by health care professionals treating Lyme disease, diverge in many of their key recommendations. Given this lack of consensus, surprisingly little research has been conducted on patient outcomes following different treatment approaches. In this study, patient outcomes from 210 Canadian Lyme disease patients seeking treatment at one US Lyme disease clinic following a treatment regimen conforming to the ILADS treatment guidelines were evaluated. It was found that the 201 of the 210 Lyme disease patients at the clinic responded positively to treatment and a significant (P<0.05) decrease in symptoms were observed over time. This study, along with related studies, may help to guide physicians to provide their patients with the most appropriate and effective means of care
Describing the mating system of Halenia deflexa, a native New Brunswick plant
Get PDFThe New Brunswick native plant Halenia deflexa (Gentianaceae) provides an excellent opportunity to investigate the association between within-plant variation in flower shape and within-plant variation in mating system. At the start of the season, H. deflexa flowers produced have long nectar spurs, but by the end of the season, nectar spur length declines significantly. This within-plant variation between early flowers and late produced flowers offers a character upon which natural selection could act. Nectar spurs offer a sugary reward to pollinators that then bring in outcross pollen for fertilization. Therefore, a decline in nectar spur length throughout the season could affect H. deflexa mating system. Halenia deflexa could be entirely self-incompatible, relying on outcrossing as its only mechanism for reproduction. On the other
hand, H. deflexa could exclusively self or have a mixed mating system where both outcrossing and selfing are used. I compared plants with full pollinator access to pollinator excluded plants in bags to investigate this potential interaction between nectar spur and mating system. However, I observed no effect of pollinator access on H. deflexa fruit set or number of seeds per fruit throughout the season. I also compared emasculated flowers with anthers removed to intact flowers to observe the effects of autogamy on H. deflexa mating system. The ability to reproduce through autogamy increases fruit set throughout the season. Autogamous fruit produce more seeds than non-autogamous fruit early in the season, but by the end of the season there is no difference between the two. Collectively, my studies indicate that H. deflexa has a mixed mating system that does not rely on pollinators to successfully reproduce
Boosting out of the blink: An attempt to modulate the attentional blink effect using the attentional boost effect
Get PDFMemory depends on attention. This principle is demonstrated in two different phenomena in attention and memory: the attentional blink effect and the attentional boost effect. The attentional blink effect is a memory deficit that occurs when targets are presented in rapid succession of each other. The attentional boost effect is a memory enhancement that occurs when participants respond to target stimuli while attending to a second set of stimuli. The current study examined whether an attentional boost effect manipulation could reduce the attentional blink deficit by having participants respond to auditory targets presented simultaneously with target words. A follow-up experiment attempted to replicate an earlier study that reduced the size of the attention blink deficit using sound alone, without the boost manipulation (Olivers and Van der Burg, 2008). Results showed no modulation of the attentional blink effect in the first experiment, but a modulation in the second experiment, wherein sound presented simultaneously with a target improved memory accuracy. Results suggested that the attentional boost effect may need to be
applied through one modality in order for a modulation of the attentional blink effect to occur
Auxosporulation and cell enlargement in thalassinoid diatoms
Get PDFOur understanding of diatom reproduction is limited, especially for marine planktonic centric diatoms. This project aimed to observe sexual behavior and auxospore development in the polar centric group, Thalassiosirales, that maintains the morphology of a nonpolar centric diatom. Auxosporulation is the main means of restoring large cell sizes in the majority of diatom species examined. Monoclonal cultures of T. weissflogii (CCMP1587), T. nordenskioeldii (CCMP997) and Thalassiosira cf. oceanica were subjected to sexual induction protocols, resulting in non-typical cells. Spermatogenesis was not observed and presumed absent in all inductions. Spherical cells with non-siliceous cell walls were observed, occurring in about 12% of the population for T. nordenskioeldii, and 17% in T. weissflogii. However, these spherical cells were not eggs or auxospores and further observations using light microscopy (LM) suggest that these cells were arrested in this stage of enlargement and eventually died. Spherical and irregular shaped cells were observed in T. weissflogii, as well as cells in general appearance similar to auxospores. The nuclear behavior observed in T. weissflogii indicates that this species could reproduce via autogamy, but mature initial cells enclosed within such “auxospores” were never observed. Inductions were not successful in Thalassiosira cf. oceanica. In the absence of gametogenesis and mature auxospores, the larger typical vegetative cells encountered in cultures following induction protocols in T. nordenskioeldii and T. weissflogii are therefore attributed to vegetative cell enlargement