257 research outputs found
Enabling learning through technology: Some institutional imperatives
This paper considers the importance of the institution as the dynamic interpretative element on which will depend the successful integration of the learning technology developed through our national initiatives into the academic curricula of HigherâEducation institutions. Based on our experience of working on teaching technology programmes, within the framework of national and institutional initiatives, it is evident that the establishment of an institutional strategy, and its implementation in a supporting universityâwide programme of staff development and training, together with strong commitment at the senior managerial level, are imperatives which determine the successful integration of learning technology within academic institutions
Erratum to: The in vitro toxicity of venoms from South Asian Hump-nosed pit vipers (Viperidae: Hypnale)
Hump-nosed pit vipers (Genus Hypnale) are venomous snakes from South India and Sri Lanka. Envenoming by Hypnale species may cause significant morbidity and is characterized by local envenoming and less commonly coagulopathy and acute renal failure. Currently there are three nominal species of this genus: H. hypnale, H. zara and H. nepa. This study investigates the biochemical and pharmacological properties of the venoms from the three Hypnale species in Sri Lanka. The three Hypnale venoms had similar chromatographic profiles using reverse phase high performance liquid chromatography and fractions with procoagulant activity were identified. Hypnale venoms had potent cytotoxicity in cultured rat aorta smooth muscle cells with similar IC50 values. The venoms had weak neurotoxic and myotoxic activity in the isolated chick biventer muscle preparation. They had mild procoagulant activity with close MCC5 values and also phospholipase activity. Locally available polyvalent antivenom did not neutralise any venom effects. The study demonstrates that the three Hypnale venoms are similar and cytotoxicity appears to be the most potent effect, although they have mild procoagulant activity. These findings are consistent with clinical reports
Biochemical status of vitamin A in colorectal cancer
Serum vitamin A and its carrier proteins, retinol-binding
protein and prealbumin, were measured in 41 colorectal cancer patients,
40 patients with benign colorectal disease, and 31 healthy subjects. Serum
samples were obtained from the Mayo Clinic (NCI-Serum diagnostic
Bank, Rochester, MN), The values for each of the three parameters were
significantly lower in colorectal cancer patients than in healthy subjects
but were litte1e different from the val ues seen in patients with benign
disease
Clinical and Experimental Applications of NIR-LED Photobiomodulation
This review presents current research on the use of far-red to near-infrared (NIR) light treatment in various in vitro and in vivo models. Low-intensity light therapy, commonly referred to as âphotobiomodulation,â uses light in the far-red to near-infrared region of the spectrum (630â1000 nm) and modulates numerous cellular functions. Positive effects of NIRâlight-emitting diode (LED) light treatment include acceleration of wound healing, improved recovery from ischemic injury of the heart, and attenuated degeneration of injured optic nerves by improving mitochondrial energy metabolism and production. Various in vitro and in vivo models of mitochondrial dysfunction were treated with a variety of wavelengths of NIR-LED light. These studies were performed to determine the effect of NIR-LED light treatment on physiologic and pathologic processes. NIRLED light treatment stimulates the photoacceptor cytochrome c oxidase, resulting in increased energy metabolism and production. NIR-LED light treatment accelerates wound healing in ischemic rat and murine diabetic wound healing models, attenuates the retinotoxic effects of methanol-derived formic acid in rat models, and attenuates the developmental toxicity of dioxin in chicken embryos. Furthermore, NIR-LED light treatment prevents the development of oral mucositis in pediatric bone marrow transplant patients. The experimental results demonstrate that NIR-LED light treatment stimulates mitochondrial oxidative metabolism in vitro, and accelerates cell and tissue repair in vivo. NIR-LED light represents a novel, noninvasive, therapeutic intervention for the treatment of numerous diseases linked to mitochondrial dysfunction
Variation in the organization and subunit composition of the mammalian pyruvate dehydrogenase complex E2/E3BP core assembly
The final version of this article is available at the link below.Crucial to glucose homoeostasis in humans, the hPDC (human pyruvate dehydrogenase complex) is a massive molecular machine comprising multiple copies of three distinct enzymes (E1âE3) and an accessory subunit, E3BP (E3-binding protein). Its icosahedral E2/E3BP 60-meric âcoreâ provides the central structural and mechanistic framework ensuring favourable E1 and E3 positioning and enzyme co-operativity. Current core models indicate either a 48E2+12E3BP or a 40E2+20E3BP subunit composition. In the present study, we demonstrate clear differences in subunit content and organization between the recombinant hPDC core (rhPDC; 40E2+20E3BP), generated under defined conditions where E3BP is produced in excess, and its native bovine (48E2+12E3BP) counterpart. The results of the present study provide a rational basis for resolving apparent differences between previous models, both obtained using rhE2/E3BP core assemblies where no account was taken of relative E2 and E3BP expression levels. Mathematical modelling predicts that an âaverageâ 48E2+12E3BP core arrangement allows maximum flexibility in assembly, while providing the appropriate balance of bound E1 and E3 enzymes for optimal catalytic efficiency and regulatory fine-tuning. We also show that the rhE2/E3BP and bovine E2/E3BP cores bind E3s with a 2:1 stoichiometry, and propose that mammalian PDC comprises a heterogeneous population of assemblies incorporating a network of E3 (and possibly E1) cross-bridges above the core surface.This work was partly supported by EPSRC (under grants GR/R99393/01 and EP/C015452/1)
A reference relative time-scale as an alternative to chronological age for cohorts with long follow-up
Background: Epidemiologists have debated the appropriate time-scale for cohort survival studies; chronological age or time-on-study being two such time-scales. Importantly, assessment of risk factors may depend on the choice of time-scale. Recently, chronological or attained age has gained support but a case can be made for a âreference relative time-scaleâ as an alternative which circumvents difficulties that arise with this and other scales. The reference relative time of an individual participant is the integral of a reference population hazard function between time of entry and time of exit of the individual. The objective here is to describe the reference relative time-scale, illustrate its use, make comparison with attained age by simulation and explain its relationship to modern and traditional epidemiologic methods.
Results: A comparison was made between two models; a stratified Cox model with age as the time-scale versus an un-stratified Cox model using the reference relative time-scale. The illustrative comparison used a UK cohort of cotton workers, with differing ages at entry to the study, with accrual over a time period and with long follow-up. Additionally, exponential and Weibull models were fitted since the reference relative time-scale analysis need not be restricted to the Cox model. A simulation study showed that analysis using the reference relative time-scale and analysis using chronological age had very similar power to detect a significant risk factor and both were equally unbiased. Further, the analysis using the reference relative time-scale supported fully-parametric survival modelling and allowed percentile predictions and mortality curves to be constructed.
Conclusions: The reference relative time-scale was a viable alternative to chronological age, led to simplification of the modelling process and possessed the defined features of a good time-scale as defined in reliability theory. The reference relative time-scale has several interpretations and provides a unifying concept that links contemporary approaches in survival and reliability analysis to the traditional epidemiologic methods of Poisson regression and standardised mortality ratios. The community of practitioners has not previously made this connection
Light smoking at base-line predicts a higher mortality risk to women than to men; evidence from a cohort with long follow-up
BACKGROUND: There is conflicting evidence as to whether smoking is more harmful to women than to men. The UK Cotton Workersâ Cohort was recruited in the 1960s and contained a high proportion of men and women smokers who were well matched in terms of age, job and length of time in job. The cohort has been followed up for 42Â years. METHODS: Mortality in the cohort was analysed using an individual relative survival method and Cox regression. Whether smoking, ascertained at baseline in the 1960s, was more hazardous to women than to men was examined by estimating the relative risk ratio women to men, smokers to never smoked, for light (1â14), medium (15â24), heavy (25+ cigarettes per day) and former smoking. RESULTS: For all-cause mortality relative risk ratios were 1.35 for light smoking at baseline (95% CI 1.07-1.70), 1.15 for medium smoking (95% CI 0.89-1.49) and 1.00 for heavy smoking (95% CI 0.63-1.61). Relative risk ratios for light smoking at baseline for circulatory system disease was 1.42 (95% CI 1.01 to 1.98) and for respiratory disease was 1.89 (95% CI 0.99 to 3.63). Heights of participants provided no explanation for the gender difference. CONCLUSIONS: Light smoking at baseline was shown to be significantly more hazardous to women than to men but the effect decreased as consumption increased indicating a dose response relationship. Heavy smoking was equally hazardous to both genders. This result may help explain the conflicting evidence seen elsewhere. However gender differences in smoking cessation may provide an alternative explanation
Metabolic switches and adaptations deduced from the proteomes of Streptomyces coelicolor wild type and phoP mutant grown in batch culture
[EN] Bacteria in the genus Streptomyces are soil-dwelling oligotrophs and important producers of secondary metabolites. Previously, we showed that global messenger RNA expression was subject to a series of metabolic and regulatory switches during the lifetime of a fermentor batch culture of Streptomyces coelicolor M145. Here we analyze the proteome from eight time points from the same fermentor culture and, because phosphate availability is an important regulator of secondary metabolite production, compare this to the proteome of a similar time course from an S. coelicolor mutant, INB201 (ÎphoP), defective in the control of phosphate utilization. The proteomes provide a detailed view of enzymes involved in central carbon and nitrogen metabolism. Trends in protein expression over the time courses were deduced from a protein abundance index, which also revealed the importance of stress pathway proteins in both cultures. As expected, the ÎphoP mutant was deficient in expression of PhoP-dependent genes, and several putatively compensatory metabolic and regulatory pathways for phosphate scavenging were detected. Notably there is a succession of switches that coordinately induce the production of enzymes for five different secondary metabolite biosynthesis pathways over the course of the batch culturesSIThis work was funded by Biotechnology and Biological Sciences Research Council Grant BB/F003439/1, ERA-NET SysMO Project GEN2006-27745-E/SYS Grant P-UK-01-11-3i, and Research Council of Norway Project 181840/I30. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked âadvertisementâ in accordance with 18 U.S.C. Section 1734 solely to indicate this fact
Ghana's Ensure Mothers and Babies Regular Access to Care (EMBRACE) program: study protocol for a cluster randomized controlled trial.
BACKGROUND: The United Nations' Millennium Development Goals call for improving maternal and child health status. Their progress, however, has been minimal and uneven across countries. The continuum of care is a key to strengthening maternal, newborn, and child health. In this context, the Japanese government launched the Ghana Ensure Mothers and Babies Regular Access to Care (EMBRACE) Implementation Research Project in collaboration with the Ghanaian government. This study aims to evaluate the implementation process and effects of an intervention to increase the continuum of care for maternal, newborn, and child health status in Ghana. METHODS/DESIGN: We will conduct a cluster randomized controlled trial using an effectiveness-implementation hybrid design in Dodowa, Kintampo, and Navrongo, Ghana. We will provide an intervention package to women living in randomly allocated intervention clusters. The study population is women of reproductive age between the ages of 15 and 49Â years. The package includes: 1) use of a new continuum of care card, 2) continuum of care orientation for health workers, 3) 24-hour health facility retention of mothers and newborns after delivery, and 4) postnatal care by home visits. We will measure maternal, newborn, and child health outcomes for both intervention and implementation impacts. The intervention outcomes are continuum of care completion rate, rate of postnatal care within 48Â hours, complication rate requiring mothers' and newborns' hospitalizations, and perinatal and neonatal mortality. The implementation outcomes are intervention coverage of the target population, intervention adoption and fidelity, implementation cost, and sustainability. DISCUSSION: In this trial, we will investigate how successful continuum of care can contribute to improving maternal, newborn, and child health outcomes. If successful, this model will then be implemented further in Ghana and other neighboring countries. TRIAL REGISTRATION: Current Controlled Trials ISRCTN90618993 . Registered on 3 September 2014
Ernst Freund as Precursor of the Rational Study of Corporate Law
Gindis, David, Ernst Freund as Precursor of the Rational Study of Corporate Law (October 27, 2017). Journal of Institutional Economics, Forthcoming. Available at SSRN: https://ssrn.com/abstract=2905547, doi: https://dx.doi.org/10.2139/ssrn.2905547The rise of large business corporations in the late 19th century compelled many American observers to admit that the nature of the corporation had yet to be understood. Published in this context, Ernst Freund's little-known The Legal Nature of Corporations (1897) was an original attempt to come to terms with a new legal and economic reality. But it can also be described, to paraphrase Oliver Wendell Holmes, as the earliest example of the rational study of corporate law. The paper shows that Freund had the intuitions of an institutional economist, and engaged in what today would be called comparative institutional analysis. Remarkably, his argument that the corporate form secures property against insider defection and against outsiders anticipated recent work on entity shielding and capital lock-in, and can be read as an early contribution to what today would be called the theory of the firm.Peer reviewe
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