121 research outputs found
Comparing men's and womens' experiences of multiple exclusion homelessness
This article explores gender as a variable in multiple exclusion homelessness in England. Much past research has taken insufficient account of the gender of homeless people, especially the predominance of men in the single homeless population and of women heading homeless households with dependent children. Drawing on qualitative data generated in a study of multiple exclusion homelessness in London and Nottingham, the article considers three ways in which gender may act as a homelessness variable: in people's susceptibility to homelessness, in their experiences of homelessness and in their encounters with accommodation services. By comparing the accounts of homeless men and women with complex support needs with evidence from staff working for support agencies, the overall aim of the article is to offer a critical examination of the gendered assumptions of homelessness policy and practice
Degradation of Chitotetraose to Chitobiose in the Axenic Rape Rhizosphere
ABSTRACT In the presence of intact roots of 2-week-old axenic rape seedlings, added Ar,JV',W,./V'"-tetraacetylchitotetraose was degraded to Af.Af'-diacetylchitobiose during 48 h of incubation. Only minute amounts of monomer (N-acetyglucosamine) were formed from added chitotetraose or chitobiose. The addition of a purified chitin suspension caused no measurable formation of degradation products. The formation of chitobiose from added chitotetraose was linear, suggesting the action of a constitutive enzyme during the incubation period
Decreased defluorination using the novel beta-cell imaging agent [18F]FE-DTBZ-d4 in pigs examined by PET
The aim of the thesis was twofold. The first aim was to radiolabel small molecules by using carbon-11 and fluorine-18 for visualising beta cell mass (BCM) in the pancreas by PET. Diabetes Mellitus (DM) is a chronic metabolic disorder that results from an absolute or relative lack of BCM of endocrine pancreas. The lack of an adequate non-invasive imaging PET probe prevents detailed examination of beta cell loss during onset and progression of DM as well as development of novel treatments and islets transplantation progress. The second aim of the thesis was to radiolabel peptide molecules with fluorine-18 to visualise beta amyloid in Alzheimerâs disease (AD) brain. AD is a chronic, progressive neurodegenerative disorder. Brain penetration study of a labelled peptide, specific for beta amyloid that can cross blood-brain-barrier (BBB), is important to gain knowledge about the fate of the molecule as a diagnostic probe.
A series of three novel radioligands for BCM imaging has been developed in this thesis. In paper I, a vesicular monoamine transporter type 2 (VMAT2) specific radioligand [18F]FE-DTBZ-d4 was synthesised in two steps. First step is the nucleophilic [18F]fluorination to produce deuterated-[18F]fluoroethylbromide followed by the O- alkylation of desmethyl-DTBZ precursor to produce [18F]FE-DTBZ-d4. The in vivo pharmacokinetics (PK) studies in pigs by PET/CT demonstrated reduced in vivo defluorination; therefore, it may be an improved potential candidate for imaging VMAT2 dense tissue i.e. islets transplantation in proximity to cortical bone structure. In Paper II, a glucokinase (GK) specific radioligand, [11C]AZ12504948, was synthesised in one step via alkylation of O-desmethyl precursor using [11C]methyl iodide. Both in vitro and in vivo (pig and monkey) studies with [11C]AZ12504948 for imaging GK in the pancreas and liver indicated low specificity. Increased target specificity is required for further progress in GK imaging using PET radioligands. In Paper III, a radioligand for G-protein coupled receptor 44 (GPR44), [11C/3H]AZ Compound X, was synthesised via S-methylation of sodium sulfinate salt in one step using [11C/3H]methyl iodide. In vitro binding of the radioligand, evaluated by autoradiography (ARG) on human and rat pancreatic tissues, confirmed higher specific binding in islets of human pancreatic tissue and no measurable binding in rat pancreas, which is devoid of GPR44. These studies indicate that the radioligand has suitable properties for beta cell imaging with high potential for further preclinical and clinical evaluation.
Three novel D-peptides were radiolabelled with fluorine-18 ([18F]ACI-87, [18F]ACI- 88, [18F]ACI-89) by using prosthetic group N-succinimidyl-4-[18F]fluorobenzoate, [18F]SFB, with epsilon (Δ)-amino groups of lysine residues of peptide precursors in two steps. First step is the synthesis of [18F]SFB followed by the addition of [18F]SFB via acylation to the peptide molecule. Trimethylammonium salt [N(CH3)3+] precursor for synthesising [18F]SFB as well as the reference standard SFB were synthesised with good yields. Three 19F-peptide reference standards were also synthesised by using SFB. Preliminary ARG measurements were performed in AD and control human brains. ARG demonstrated higher radioligand uptake in the AD brain compared to age-matched control brain, which makes them potential for further use in in vivo testing by PET. However, preliminary PET (in vivo) studies in cynomolgus monkey brain, using these 18F-D-peptides, confirmed too low BBB penetration, making them unsuitable for further use as in vivo PET probes
Experience Report: Thinkathon -- Countering an "I Got It Working" Mentality with Pencil-and-Paper Exercises
Goal-directed problem-solving labs can lead a student to believe that the most important achievement in a first programming course is to get programs working. This is counter to research indicating that code comprehension is an important developmental step for novice programmers. We observed this in our own CS-0 introductory programming course, and furthermore, that students weren't making the connection between code comprehension in labs and a final examination that required solutions to pencil-and-paper comprehension and writing exercises, where sound understanding of programming concepts is essential. Realising these deficiencies late in our course, we put on three 3-hour optional revision evenings just days before the exam. Based on a mastery learning philosophy, students were expected to work through a bank of around 200 pencil-and-paper exercises. By comparison with a machine-based hackathon, we called this a Thinkathon. Students completed a pre and post questionnaire about their experience of the Thinkathon. While we find that Thinkathon attendance positively influences final grades, we believe our reflection on the overall experience is of greater value. We report that: respected methods for developing code comprehension may not be enough on their own; novices must exercise their developing skills away from machines; and there are social learning outcomes in programming courses, currently implicit, that we should make explicit
Evaluating the Ability of Constructed Intertidal Eastern Oyster (\u3ci\u3eCrassostrea virginica\u3c/i\u3e) Reefs to Address Shoreline Erosion in South Carolina
The application of nature-based solutions to address shoreline erosion and the loss of salt marsh in coastal South Carolina has centered around the creation of intertidal oyster (Crassostrea virginica) reefs that act as natural breakwaters. The installation of such living shoreline materials often results in a rapid accumulation of fine sediments, followed by wild oyster recruitment to suitable materials, and then more gradually the growth of salt marshes (primarily Spartina alterniflora). Leveraging more than two decades of oyster reef restoration and living shorelines research at the South Carolina Department of Natural Resources, this study quantitatively assessed performance rates for both percent oyster cover and marsh protection in relation to reef age. Determining such rates will serve to inform the expectations of prospective adopters of living shorelines as to the timeframes of some of the biological processes, as measures of performance success, that will occur following material installation. Performance success was investigated in terms of recruitment of oysters to installed materials and the creation of new marsh habitat or protection of existing marsh from erosion. Reef age was an important determinant of reef âsuccessâ, with significant relationships between reef age and both performance success metrics. Percent oyster cover reached 40% by two years post-installation and 50% by four years post-installation, indicative of high rates of oyster recruitment. The relative marsh protection rate of living shorelines compared to unprotected reference plots was 0.4 m yr-1 Reef performance differed based on bank substrate firmness, bank width, shoreline morphology, and location relative to the Intracoastal Waterway (ICW). Firmer bank substrate was associated with greater percent oyster cover. Broader bank width was associated with greater marsh protection. Higher percent oyster cover measurements were observed on straight, natural shorelines and reefs located along the ICW. Reefs located on the ICW were also associated with greater marsh protection than reefs at non-ICW sites. Further, this study demonstrates that bagged oyster shell reefs are capable of providing shoreline protection services for more than a decade and can endure multiple intense storm events. The results of this study were also used to facilitate the implementation of new living shoreline regulations in coastal South Carolina in the hope of broadening adoption of this approach to addressing shoreline erosion and salt marsh habitat loss
Changing epidemiology and age-specific incidence of cutaneous malignant melanoma in England: an analysis of the national cancer registration data by age, gender and anatomical site, 1981 2018
Background:
The incidence of cutaneous malignant melanoma, which is mostly attributable (86%) to UV radiation exposure, has been steadily increasing over the past four decades in predominantly fair-skinned populations. Although public health campaigns are increasing sun-protective behaviour in England, their effect on melanoma incidence is largely unknown. We conducted a retrospective population-based cohort study to examine whether there have been changes in the epidemiology of melanoma in England during the past four decades.
Methods:
Individual level data for patients diagnosed with melanoma in England during 1981-2018 were obtained from the Office for National Statistics/Public Health England. Average annual incidence rates were calculated by three age categories (0-34, 35-64, 65+ years), gender and anatomical site during the seven five-year time periods (1981-85 to 2011-15) and the recent three-year period (2016-18). The percentage change in incidence was calculated as change in the average incidence rate from the first (1981-85) to the last time period (2016-18). The Average Annual Percentage Change (AAPC) was estimated using the slope of the linear trend line fitted to the incidence rates by year of diagnosis.
Findings:
During the 38-year period (1981-2018), a total of 265,302 cases of melanoma (45.7% males, 54.3% females) were registered in England. The average annual number of cases increased from 837/year in 1981-85 to 6,963/year in 2016-18 in males (+732%), and from 1,609/year in 1981-85 to 6,952/year in 2016-18 in females (+332%). In the young age-group (0-34 years), the average annual incidence rates initially increased from 1981-85 to 2001-05 and then stabilised during the recent period (2006-18). In the middle age group (35-64 years), the rates increased by +332% (AAPC, 10.4%) in males (from 5.6/100,000 in 1981-85 to 24.2/100,000 in 2016-18) and +185% (AAPC, 5.7%) in females (from 10.2/100,000 in 1981-85 to 29.1/100,000 in 2016-18); and in the old age-group (65+ years) the rates increased by +842% (AAPC, 25.7%) in males (from 9.6/100,000 in 1981-85 to 90.4/100,000 in 2016-18) and +381% (AAPC 11.2%) in females (from 12.5/100,000 in 1981-85 to 60.1/100,000 in 2016-18). The largest increase in incidence in both males and females was observed for melanoma of the trunk (+817%, AAPC, 24.8% in males and +613%, AAPC, 18.3% in females), followed by melanoma of upper limb (+750%, AAPC, 22.9% in males and 518%, AAPC, 15.5% in females).
Interpretation:
It appears that the incidence of melanoma among young people in England has stabilised (or levelled off) in recent decades, whereas it continues to increase substantially in older population. These findings suggest that public health campaigns targeted at children/adolescents/parents may be favourably influencing melanoma incidence. The steeper increase in incidence in males is consistent with their relatively greater sun exposure and poor sun-protective behaviour. All the available evidence suggests that the enormous increase in the melanoma of the trunk and upper limb, since the 1980s, is most likely due to increasing trend in intermittent high intensity recreational UV radiation exposure (e.g. sunbathing, holidaying in places with strong sunlight, indoor tanning)
âBreaking up is hard to doâ: the formation and resolution of sister chromatid intertwines
The absolute necessity to resolve every intertwine between the two strands of the DNA double helix provides a massive challenge to the cellular processes that duplicate and segregate chromosomes. Although the overwhelming majority of intertwines between the parental DNA strands are resolved during DNA replication, there are numerous chromosomal contexts where some intertwining is maintained into mitosis. These mitotic sister chromatid intertwines (SCIs) can be found as; short regions of unreplicated DNA, fully replicated and intertwined sister chromatidsâcommonly referred to as DNA catenationâand as sister chromatid linkages generated by homologous recombination-associated processes. Several overlapping mechanisms, including intra-chromosomal compaction, topoisomerase action and Holliday junction resolvases, ensure that all SCIs are removed before they can prevent normal chromosome segregation. Here, I discuss why some DNA intertwines persist into mitosis and review our current knowledge of the SCI resolution mechanisms that are employed in both prokaryotes and eukaryotes, including how deregulating SCI formation during DNA replication or disrupting the resolution processes may contribute to aneuploidy in cancer
The Unequal World of Health Data
Peter Byass argues that less data are available on the health of the poor than of the rich, and discusses several alternative strategies to improve the representativeness of health data
A Prospective Study of the Association of Metacognitive Beliefs and Processes with Persistent Emotional Distress After Diagnosis of Cancer
Two hundred and six patients, diagnosed with primary breast or prostate cancer completed self-report questionnaires on two occasions: before treatment (T1) and 12 months later (T2). The questionnaires included: the Hospital Anxiety and Depression Scale; Impact of Events Scale; the Metacognitions Questionnaire-30 (MCQ-30) and the Illness Perceptions Questionnaire-revised. A series of regression analyses indicated that metacognitive beliefs at T1 predicted between 14 and 19 % of the variance in symptoms of anxiety, depression and trauma at T2 after controlling for age and gender. For all three outcomes, the MCQ-30 subscale ânegative beliefs about worryâ made the largest individual contribution with âcognitive confidenceâ also contributing in each case. For anxiety, a third metacognitive variable, âpositive beliefs about worryâ also predicted variance in T2 symptoms. In addition, hierarchical analyses indicated that metacognitive beliefs explained a small but significant amount of variance in T2 anxiety (2 %) and T2 depression (4 %) over and above that explained by demographic variables, T1 symptoms and T1 illness perceptions. The findings suggest that modifying metacognitive beliefs and processes has the potential to alleviate distress associated with cancer
Best paper award: Experience report: thinkathon - countering an 'I got it working' mentality with pencil-and-paper exercises
Goal-directed problem-solving labs can lead a student to believe that the most important achievement in a first programming course is to get programs working. This is counter to research indicating that code comprehension is an important developmental step for novice programmers. We observed this in our own CS-0 introductory programming course, and furthermore, that students werenât making the connection between code comprehension in labs and a final examination that required solutions to pencil-and-paper comprehension and writing exercises, where sound understanding of programming concepts is essential. Realising these deficiencies late in our course, we put on three 3-hour optional revision evenings just days before the exam. Based on a mastery learning philosophy, students were expected to work through a bank of around 200 pencil-and-paper exercises. By comparison with a machine-based hackathon, we called this a Thinkathon. Students completed a pre and post questionnaire about their experience of the Thinkathon. While we find that Thinkathon attendance positively influences final grades, we believe our reflection on the overall experience is of greater value. We report that: respected methods for developing code comprehension may not be enough on their own; novices must exercise their developing skills away from machines; and there are social learning outcomes in programming courses, currently implicit, that we should make explicit
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