566 research outputs found

    Low Temperature Expansions for Potts Models

    Full text link
    On simple cubic lattices, we compute low temperature series expansions for the energy, magnetization and susceptibility of the three-state Potts model in D=2 and D=3 to 45 and 39 excited bonds respectively, and the eight-state Potts model in D=2 to 25 excited bonds. We use a recursive procedure which enumerates states explicitly. We analyze the series using Dlog Pade analysis and inhomogeneous differential approximants.Comment: (17 pages + 8 figures

    24-Hour Rhythms of DNA Methylation and Their Relation with Rhythms of RNA Expression in the Human Dorsolateral Prefrontal Cortex

    Get PDF
    Circadian rhythms modulate the biology of many human tissues, including brain tissues, and are driven by a near 24-hour transcriptional feedback loop. These rhythms are paralleled by 24-hour rhythms of large portions of the transcriptome. The role of dynamic DNA methylation in influencing these rhythms is uncertain. While recent work in Neurospora suggests that dynamic site-specific circadian rhythms of DNA methylation may play a role in modulating the fungal molecular clock, such rhythms and their relationship to RNA expression have not, to our knowledge, been elucidated in mammalian tissues, including human brain tissues. We hypothesized that 24-hour rhythms of DNA methylation exist in the human brain, and play a role in driving 24-hour rhythms of RNA expression. We analyzed DNA methylation levels in post-mortem human dorsolateral prefrontal cortex samples from 738 subjects. We assessed for 24-hour rhythmicity of 420,132 DNA methylation sites throughout the genome by considering methylation levels as a function of clock time of death and parameterizing these data using cosine functions. We determined global statistical significance by permutation. We then related rhythms of DNA methylation with rhythms of RNA expression determined by RNA sequencing. We found evidence of significant 24-hour rhythmicity of DNA methylation. Regions near transcription start sites were enriched for high-amplitude rhythmic DNA methylation sites, which were in turn time locked to 24-hour rhythms of RNA expression of nearby genes, with the nadir of methylation preceding peak transcript expression by 1–3 hours. Weak ante-mortem rest-activity rhythms were associated with lower amplitude DNA methylation rhythms as were older age and the presence of Alzheimer's disease. These findings support the hypothesis that 24-hour rhythms of DNA methylation, particularly near transcription start sites, may play a role in driving 24-hour rhythms of gene expression in the human dorsolateral prefrontal cortex, and may be affected by age and Alzheimer's disease

    Finite element simulation in biomechanics: bone and dental cements

    Get PDF
    This paper is concerned with the accuracy of numerical modelling in implant analysis. The discretisation error in a given finite element calculation is estimated and the mesh is refined accordingly. Furthermore, the need for accurate modelling of the constitutive laws of the involved material is stressed. An isotropic model for bone is tested versus an orthotropic one. When modelling the setting process of a polymer-based tooth filling, time-dependent viscous flow occurring in the restorative material is taken into account and the results are compared to the linear case

    In vitro anti-malarial interaction and gametocytocidal activity of cryptolepine

    Get PDF
    YesBackground: Discovery of novel gametocytocidal molecules is a major pharmacological strategy in the elimination and eradication of malaria. The high patronage of the aqueous root extract of the popular West African anti-malarial plant Cryptolepis sanguinolenta (Periplocaceae) in traditional and hospital settings in Ghana has directed this study investigating the gametocytocidal activity of the plant and its major alkaloid, cryptolepine. This study also investigates the anti-malarial interaction of cryptolepine with standard anti-malarials, as the search for new anti-malarial combinations continues. Methods: The resazurin-based assay was employed in evaluating the gametocytocidal properties of C. sanguinolenta and cryptolepine against the late stage (IV/V) gametocytes of Plasmodium falciparum (NF54). A fixed ratio method based on the SYBR Green I fluorescence-based assay was used to build isobolograms from a combination of cryptolepine with four standard anti-malarial drugs in vitro using the chloroquine sensitive strain 3D7. Results: Cryptolepis sanguinolenta ( IC50 = 49.65 nM) and its major alkaloid, cryptolepine ( IC50 = 1965 nM), showed high inhibitory activity against the late stage gametocytes of P. falciparum (NF54). In the interaction assays in asexual stage, cryptolepine showed an additive effect with both lumefantrine and chloroquine with mean ΣFIC50s of 1.017 ± 0.06 and 1.465 ± 0.17, respectively. Cryptolepine combination with amodiaquine at therapeutically relevant concentration ratios showed a synergistic effect (mean ΣFIC50 = 0.287 ± 0.10) whereas an antagonistic activity (mean ΣFIC50 = 4.182 ± 0.99) was seen with mefloquine. Conclusions: The findings of this study shed light on the high gametocytocidal properties of C. sanguinolenta and cryptolepine attributing their potent anti-malarial activity mainly to their effect on both the sexual and asexual stages of the parasite. Amodiaquine is a potential drug partner for cryptolepine in the development of novel fixed dose combinations

    Strategies to resolve problems of the Leasehold Forestry Program

    Get PDF
    Meeting: Celebrating Dialogue : An International SAS2 Forum, November 3, 2008, Carleton University, Ottawa, ON, CASAS reports are made available in order to provide timely access to the information by interested researchers. This report has been subject to an internal review process to ensure accuracy and quality

    An Unusual Case of Accidental Ingestion of a Toothbrush

    Get PDF
    Introduction: Foreign body ingestion is a common presenting complaint in the emergency department. While ingestion of small foreign bodies like coins and button batteries is not uncommon, ingestion of long and rigid foreign bodies like toothbrush is very rare. Case presentation: We describe a 36-year-old man who presented to us after accidental ingestion of a toothbrush. The patient underwent urgent endoscopic removal; Psychiatric evaluation revealed an acute and transient psychotic disorder in him. Conclusion: Ingestion of long and rigid foreign bodies like a toothbrush is an uncommon entity. Such foreign bodies when ingested find it difficult to maneuver through the GI tract, which makes their spontaneous passage almost impossible. Their ingestion is associated with increased risk of impaction, perforation and, bleeding. Therefore, early removal of the ingested toothbrush is recommended before complications develop

    Sickle cell disease: reappraisal of the role of foetal haemoglobin levels in the frequency of vaso-occlusive crisis

    Get PDF
    Background: Foetal haemoglobin has been implicated in the modulation of sickle cell crisis. Its level is generally inversely proportional to the severity of sickle cell disease (SCD) for a given sickle cell phenotypes. The main aim of therapy for vaso-occlusive crisis (VOC), which is the hallmark of SCD, is to reduce the chances of sickling through the prevention of polymerization of HbS. One way of preventing this polymerization is by increasing foetal haemoglobin levels.Objectives: To determine the relationship between HbF levels and the frequency of crisis in SCD patients in Ghana.Method: A longitudinal retrospective survey covering a period of 30 months was carried out on adult SCD patients at the Sickle Cell Clinic of the Korle-Bu Teaching Hospital.Results: Eighty-three adults aged 15 to 65 years made up of 40 males and 43 femalea were studied. Analysis of variance (ANOVA) gave significant results in Hb and HbF levels. Higher HbF levels were positively related to less frequent crisis and were significantly high in SCD patients than in controls. HbF effects on the clinical manifestations on SCD were variable.Conclusion: Threshold values of HbF play a role in reducing the frequency of vaso-occlusive crisis in SCD patients and this finding contributes to the body of available literature on SCD severity. However our work does not give the apparent threshold level of helpful HBF Level in SCD.Keywords: Haemoglobin F, Frequency of crisis, sickle cell disease

    ALLN-177, oral enzyme therapy for hyperoxaluria

    Get PDF
    PURPOSE: To evaluate the potential of ALLN-177, an orally administered, oxalate-specific enzyme therapy to reduce urine oxalate (UOx) excretion in patients with secondary hyperoxaluria. METHODS: Sixteen male and female subjects with both hyperoxaluria and a kidney stone history were enrolled in an open-label study. Subjects continued their usual diets and therapies. During a 3-day baseline period, two 24-h (24-h) urines were collected, followed by a 4-day treatment period with ALLN-177 (7,500 units/meal, 3 × day) when three 24-h urines were collected. The primary endpoint was the change in mean 24-h UOx from baseline. Safety assessments and 24-h dietary recalls were performed throughout. RESULTS: The study enrolled 5 subjects with enteric hyperoxaluria and 11 with idiopathic hyperoxaluria. ALLN-177 was well tolerated. Overall mean (SD) UOx decreased from 77.7 (55.9) at baseline to 63.7 (40.1) mg/24 h while on ALLN-177 therapy, with the mean reduction of 14 mg/24 h, (95% CI - 23.71, - 4.13). The calcium oxalate-relative urinary supersaturation ratio in the overall population decreased from a mean of 11.3 (5.7) to 8.8 (3.8) (- 2.8; 95% CI - 4.9, - 0.79). This difference was driven by oxalate reduction alone, but not any other urinary parameters. Mean daily dietary oxalate, calcium, and fluid intake recorded by frequent diet recall did not differ by study periods. CONCLUSION: ALLN-177 reduced 24-h UOx excretion, and was well tolerated. The results of this pilot study provided justification for further investigation of ALLN-177 in patients with secondary hyperoxaluria

    Circulating Angiogenic Growth Factors in Diabetes Patients with Peripheral Arterial Disease and Exertional Leg Pain in Ghana

    Get PDF
    Objective. Peripheral arterial disease (PAD) is a common complication of diabetes, associated with impairment in angiogenesis. Angiogenesis is regulated by angiogenic growth factors such as angiopoietin 1 (Ang-1), Ang-2, and vascular endothelial growth factor (VEGF). We studied the association between angiogenic growth factors versus PAD and exertional leg symptoms in diabetes patients in Ghana. Method. In this cross-sectional study, ankle-brachial index was measured with oscillometrically and exertional leg symptoms were screened with Edinburgh claudication questionnaire in 140 diabetes patients and 110 nondiabetes individuals. Circulating levels of Ang-1, Ang-2, and VEGF were measured with immunosorbent assay. Results. The prevalence of PAD and exertional leg pain was 16.8% and 24.8%, respectively. Compared to non-PAD participants, PAD patients had higher VEGF levels [85.8 (37.5–154.5) versus 57.7 (16.6–161.1) p=0.032] and lower Ang-1 levels [31.3 (24.8–42.6) versus 40.9 (28.2–62.1), p=0.017]. In multivariable logistic regression, patients with exertional leg pain had increased the odds of plasma Ang-2 levels [OR (95% CI): 2.08 (1.08–6.41), p=0.036]. Conclusion. Diabetes patients with PAD and exertional leg pain have imbalance in angiogenic growth factors, indicating impaired angiogenesis. In patients with exertional leg pains, Ang-2 may be an important biomarker

    Rape myth acceptance : gender and cross-national comparisons across the United States, South Africa, Ghana, and Nigeria

    Get PDF
    Many studies indicate that rape-supportive beliefs persist and influence sexually aggressive behaviors and hostility toward women. Despite the plethora of studies, cross-cultural knowledge remains sparse. The present study examined rape myth acceptance across gender and countries (i.e., United States, South Africa, Ghana, and Nigeria). An online questionnaire was administered to a convenience sample of 699 respondents in the four countries. Results suggested that respondents in Nigeria were the most likely and respondents in United States were the least likely to endorse rape myths. Respondents in South Africa were less likely than respondents in Ghana to endorse the myth that the female victim of rape “asked for it” and that the male perpetrator “didn’t mean to” rape the female victim. Although men were more likely than women to endorse rape myths, female respondents in Nigeria endorsed the myths “she asked for it” and “he didn’t mean to” more than did male respondents in Nigeria. In general, exposure to various patriarchal structures and ideologies; differences in preventive, protective, and punitive policy responses to gender-based violence; repressive cultural and religious practices; reinforcement of demeaning stereotypes against women; and psychological assimilation of oppressive policy, values and beliefs may be responsible for cross-national differences. Cross-country differences in rape myths suggest the need for formal and informal intervention in vulnerable countries. International transfer of effective policies and programs for combating gender-based violence in protective countries might lead to considerable changes in vulnerable countries and help to shift the focus from patriarchal to egalitarian views of women.http://link.springer.com/journal/12119hj2022Social Work and Criminolog
    corecore