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The impact of L-arginine on cannabinoid 1 receptor expression, neuronal excitability, and synaptic transmission in the hypothalamus of young rats
Get PDFInteractions between nitric oxide (NO) and endogenous cannabinoids (eCBs) have been reported in various brain regions including dorsomedial hypothalamus (DMH). Such interactions include that eCBs diminish NO signaling and NO is required for eCB signaling. I aimed to determine if the requirement of NO for eCB signaling is mediated by CB1R expression. To determine the effects of NO on CB1R expression, young male Sprague Dawley rats were divided into two groups: (1) acute robust exposure to L-arginine (100mg/kg) by intraperitoneal injection or vehicle (saline) injection and (2) prolonged modest exposure to L-arginine by supplemented water (2.25%) and control distilled water for control. It was determined by RT-PCR that the hypothalamus of animals receiving an acute exposure to L-arginine showed a significant increase in CB1R mRNA, but not the cortex or hippocampus. Prolonged treatment with L-arginine water did not cause a significant change in CB1R expression. Results from RT-PCR experiments lead to obtaining electrophysiological recordings from the DMH, a region known to exhibit interactions between NO and eCBs. Electrophysiological recordings were used to determine the effects of L-arginine on neuronal excitability and synaptic transmission at glutamate synapses. To do this, animals received the same acute and robust exposure to L-arginine that was found to increase CB1R mRNA in the hypothalamus. Whole cell recordings from DMH neurons were performed to determine the effect of L-arginine on neuronal excitability and the ability of glutamate synapses to undergo long-term changes in synaptic strength in response to high frequency stimulation (HFS). It was found that glutamate synapses from animals receiving Larginine injections were less excitable than those from vehicle-treated animals. In animals receiving a vehicle treatment, there was a short-term potentiation of glutamate signaling
observed in the first five-minutes after HFS. This short-term potentiation was abolished in animals which received L-arginine. No long-term changes in synaptic strength were observed with either treatment. These findings suggest that L-arginine may increase CB1R expression in the DMH, causing a decrease in neuronal excitability as well as masking short-term potentiation post-HFS at glutamate synapses. Future research is required to confirm if the L-arginine effects on neuronal excitability and synaptic transmission are CB1R mediated
An analysis of contemporary microfinance and the impacts of mission drift in the field of international development
Get PDF(In lieu of the Abstract, this is the Introduction)
Between the 1970s and the 1990s, the concept of microfinance as a strategic anti-poverty mechanism occupied a vast and dynamic space within the field of international development. Popularized by economist and 2006 Nobel Peace Prize co-recipient Dr. Muhammad Yunus, microfinance is rooted in a local experiment in Bangladesh with the purpose of promoting self-employment and small-scale entrepreneurship, particularly among impoverished and disempowered women. During the first stages of its development, microfinance was arguably a revolutionary concept for poverty alleviation. Its original objective was to reach the most impoverished through the provision of small loans that could be used for entrepreneurial endeavors and revenue generating projects. Microfinance was seen as a way to reduce extreme poverty, empower women, and increase the quality of life for the borrowers. Between 1997 and 2005 the number of microfinance institutions increased from 618 to 3,133, and the number of borrowers rose from 13.5 million to 113.3 million (84 % of them being women) (Hermes and Lensink, 2007).
After gaining popularity and support from development scholars, policy circles, and the public as a poverty alleviating tool, microfinance as a concept also became an attractive revenue generating site for profit seeking commercial banks and multi-national corporations. The expansion of microfinance policy opened up a new opportunity for commercial banks to integrate microfinance into their banking portfolios, which was framed as an effort to better serve the impoverished by increasing the value and amount of loans available to them. More in-depth and frequent evaluations of microfinance success rates have brought to light the corrupt and manipulative potential that microfinance has when used in a profit seeking context, leaving the practice as a target of moral criticism and ethical questioning (Hudon, 2011). Notable scholars, such as Karim (2008), suggests how the shift that microfinance has experienced in the late 1990s and early 2000’s, from a bottom up, grassroots approach to poverty reduction, to a top down, profit seeking approach, runs in parallel with the spread of neoliberal economic policy to developing communities, further ingraining dependent relations between the powerful rich and the vulnerable poor. In addition, the culturally insensitive practices of many profit seeking microfinance institutions not only perpetuate the debt cycle and expand the neoliberalglobalization agenda to the South, but they can also trigger conditions such as mass suicides and severe stress related health problems (Ashta, et al., 2011).
The following study will engage with the dangers and negative impacts that small microfinance institutions face when they are co-opted by profit seeking commercial banks and other for-profit financial institutions. It will highlight the deliberate and exploitative measures that further develop dependent relationships between borrowers and lenders through pushing the impoverished deeper into poverty traps and debt cycles. It will suggest the necessity of reevaluating modern microfinance practices as a poverty alleviation tool, and present valuable innovations that microfinance institutions have used in their programs in order to create a sustainable and well-rounded poverty alleviation tool. The main focus of the analysis will establish the high risk of mission drift that modern day microfinance institutions encounter, as the scope of microfinance within international development continues to lean more towards neoliberal economic policy, rather than grassroots, not-for-profit development strategies, and how this is a detriment to the borrowers who are involved. Throughout the analysis, this thesis will also highlight the large gap in empirical research within the study of microfinance that further deepens the divide between critics and advocates of microfinance, as the evidence for or against microfinance is typically limited to anecdotal instances or cases. The study concludes by claiming that the commercialization of microfinance organizations is an inefficient, exploitative, and contradictory attempt at the original aim of microfinance and its poverty alleviation vision, and that grassroots microfinance organizations who strive for capacity expansion through commercialization effectively limit their success of poverty alleviation through their risk of mission drift, or complete co-optation by commercial organizations. The following portion of the introduction provides a brief context of microfinance, in addition to the discussing the two key questions of this study: 1) What is the context of the borrowers’ situation, and is microfinance effective in alleviating their impoverished situation? and 2) What are the risks and negative impacts of mission drift, and how has the commercialization of microfinance created a counter intuitive economic concept that actively exploits and deepens the socio-economic disparities within developing communities
Gold nanoparticle surface chemistry affects multiple parameters of cytotoxicity in an ovarian cancer model
Get PDFOvarian cancer is one of the deadliest types of cancer, and traditional treatments such as chemotherapy and radiation therapy cause harmful side effects to healthy tissue. Contemporary medicine has become more personalized, and the field of nanomedicine has developed in an attempt to develop more targeted cancer treatments to reduce these off-target effects. Gold nanoparticles (AuNP) are of particular interest because of their unique and modifiable physicochemical properties as well as high biocompatibility and low immunogenicity. This study investigated AuNP conjugated to four different ligands with distinct surface chemistry: polyethylene glycol (PEG), trimethylamine bromide (TMAB), 4-dimethylaminopyridine (DMAP), and carboxyl (COOH). The impact of AuNP surface chemistry upon various parameters of cytotoxicity in SKOV3 ovarian cancer cells was evaluated with a range of cytotoxicity assays. Parameters of cytotoxicity assessed in this study include metabolic function as measured with an MTT assay, oxidative stress as measured by a DCF assay, cell health as measured by a colony forming assay, and cell viability as measured by a neutral red assay. Morphological features of SKOV3 cells treated with each AuNP were also examined for characteristics of cell death. Results of these cytotoxicity and morphological evaluations suggest that AuNP-PEG induce apoptotic cell death, AuNP-TMAB induce oxidative stress that does not result in cell death, AuNP-DMAP induce autophagy cell death, and AuNP-COOH induce anoikis-apoptotic cell death. Future studies include further AuNP functionalization and the immunologic detection of components of cell death pathways
The dual-hormone hypothesis and decision making
Get PDFDecision making is a part of everyday life, so it is important to understand the mechanisms that influence it. Hormonal mechanisms likely play a role, and both testosterone and cortisol have been demonstrated to alter cognition. The purpose of this study was to examine how testosterone and cortisol are related to decision making. Fortythree undergraduate students participated (30 women, 13 men, mean age = 19).
Participants provided a saliva sample immediately before completing two measures, the Cognitive Reflection Test (CRT) and the CRT-2. It was hypothesized that higher salivary testosterone levels would predict lower scores on the CRT and the CRT-2. Taking into account the dual-hormone hypothesis, it was hypothesized that the relationship between testosterone and cognitive reflection would be moderated by salivary cortisol, such that the relationship would not exist when cortisol levels were high. Testosterone was not correlated with CRT scores, but cortisol was negatively correlated with CRT scores for
men only. In a multiple regression analysis with testosterone, cortisol, and their interaction predicting CRT scores, the overall model was significant for men, but no individual variables predicted CRT scores. There was no relationship between hormones and CRT scores for women. Further research is needed to help clarify the impact of these hormones on decision making
Metabolic responses of the Maugean skate (Zearaja maugeana) to chronic hypoxia and hyposalinity
Get PDFThe endangered Maugean skate faces a variety of anthropogenic and physicochemical
challenges in its endemic habitat of Macquarie Harbour, Tasmania, Australia. Among these
challenges are highly stratified waters with variable temperatures, oxygen saturation, and
salinity, and increasing salmonid aquaculture. It is known that the skate is capable of tolerating
short-term hypoxic exposure, but much of its physiology remains unknown. Decreasing trends in
oxygen saturation throughout all layers of the harbour over the last decade correspond with
increases in salmonid aquaculture, and increased occurrences of major storms may exacerbate
these declines. As such, I investigated the Maugean skate’s physiological responses to chronic
hypoxia to understand what affect it may have on these endangered animals. I exposed the skates
to either hypoxia (20% DO) or normoxia (90% DO) for 96-hours, immediately after which, I
measured their metabolic rate at 20% DO. I quantified lactate and glycogen concentrations in
tissue samples taken immediately following the metabolic rate test and both pre- and postexposure
plasma samples. I found that skates exposed to hypoxia for 96-hours exhibited
significantly lower metabolic rates than their normoxic counterparts. Plasma lactate
concentrations were undetectable in the field, and there was no significant difference in tissue
lactate or glycogen concentrations relative to normoxic tissues. My results indicate that the
Maugean skate is extremely hypoxia tolerant and copes with chronic hypoxia by depressing its
metabolism to potentially limit glycogen use and lactate production. While the skates seem to be
able to tolerate chronic hypoxia through metabolic depression, this may limit their ability to
forage and/or reproduce, which may inhibit population recovery
Agrobacterium-mediated transformation of ixodes scapularis
Get PDFIxodes scapularis is a vector for numerous pathogens of humans and animals in North America,
with its population and territories expanding due to climate change, change of land-use, and other
factors. Many of these pathogens can have debilitating or even fatal effects, so methods to control
ticks are vital. With increasing consideration and use of transgenic mosquitoes to stem the spread of
mosquito-vectored pathogens, similar work using ticks could be considered. This project sought to
replicate and expand upon the work of Machado-Ferreira in 2015 reporting the use of Agrobacterium
tumefaciens to insert a transgene construct expressing enhanced green fluorescent protein (eGFP)
into ticks. Images of surface-sterilized treated ticks show spots of especially noticeable fluorescence
which is promising, however, further molecular testing is needed to provide a definitive answer to
whether these ticks are truly transgenic
Microfiber uptake by freshwater mussels in tributaries of the Saint John River Watershed, New Brunswick
Get PDFRecognized as a potential novel environmental stressor, microfibers are a widespread contaminant of anthropogenic origin. Many enter aquatic systems through wastewater treatment plant (WWTP) effluent and may persist in the environment indefinitely. Although the environmental impacts of microfibers are not well-understood, they are suspected to play a role in the dispersal of chemicals and other contaminants throughout aquatic systems and may impair feeding and respiration of aquatic filter-feeding organisms due to their tendency to accumulate on digestive and respiratory tissues. This study aimed to determine whether freshwater mussels in the Saint John River watershed acquire microfibers on or within their tissues, and if so, whether microfiber abundance was related to WWTP discharge points and other potential diffuse microfiber sources. Microfiber abundance was assessed in mussels of the species Margaritifera margaritifera L., which were collected both upstream and downstream of WWTP discharge points and at intermediate sampling points along the Kennebecasis and Tobique rivers. No spatial trends were observed in microfiber abundance in relation to WWTP discharge on either river. Mussels from the Tobique River had significantly (p < 0.01) more microfibers per gram of soft tissue than those from the Kennebecasis. These results help reveal a potential pathway through which microfibers may be entering aquatic food webs and addresses the plausibility of using mussels as bioindicators of microfiber contamination
Pairwise completely positive matrices with applications in Quantum Information Theory
Get PDFThis thesis introduces a generalization of the set of completely positive matrices that we call “pairwise completely positive” (PCP) matrices. PCP matrix pairs are defined so that one matrix in the pair is necessarily positive semidefinite while the other is necessarily entrywise non-negative. After PCP matrices are defined we explore their basic properties and establish numerous necessary and sufficient conditions that can help test whether or not a pair meets our definition of PCP. We then relate these matrix pairs to the separability of conjugate local diagonal unitary invariant (CLDUI) quantum states. In particular, we show that determining whether or not a pair of matrices is pairwise completely positive is equivalent to determining whether or not a corresponding
CLDUI state is separable