Education and Mortality: Evidence from a Social Experiment

ducational reform that increased the years of compulsory schooling. Using the gradual phase-in of the reform between 1949 and 1962 across municipalities, we estimate insignificant effects of the reform on mortality in the affected cohort. From the confidence intervals, we can rule out effects larger than 1–1.4 months of increased life expectancy. We find no significant impacts on mortality for individuals of low socioeconomic status backgrounds, on deaths that are more likely to be affected by behavior, on hospitalizations, and consumption of prescribed drugs

Crossing power and knowledge boundaries in learning and knowledge sharing

Purpose – The purpose of this paper is to investigate the crossing of knowledge and power boundaries within a bureaucratic organization using Enterprise Social Media (ESM). Carlile’s (2004) boundary crossing framework is used to guide this research. Design/methodology/approach- This is a qualitative study based on semi-structured interviews and observations in a large Norwegian public sector organization. Findings- We find that crossing knowledge and power boundaries using ESM is problematic at both a syntactic, semantic and pragmatic level. ESM is used predominantly for sharing, storing and retrieving explicit knowledge, which is a display of crossing the information processing boundary. While the use of ESM allows for potential power shifts among different levels, shared meaning, taking the perspective of other and new knowledge-in-practices are not achieved. Therefore examples of crossing the semantic and pragmatic knowledge boundaries are rarely found. Research limitations/implications- The framework could be applied to a variety of contexts to further explore the role of ESM in learning and knowledge sharing and its ability to cross power and knowledge boundaries. Practical implications- Organizations will benefit from understanding issues related to the use of ESM to enhance knowledge sharing, learning and the development of new practices, as well as potential power, knowledge and trust issues that may arise in connection with the use of ESM. Originality/value – This paper addresses a gap in the literature around discussions of power, trust, boundary crossing and the use of enterprise social media for knowledge sharing and learnin

The Role of Biomethylation in Toxicity and Carcinogenicity of Arsenic: A Research Update

Recent research of the metabolism and biological effects of arsenic has profoundly changed our understanding of the role of metabolism in modulation of toxicity and carcinogenicity of this metalloid. Historically, the enzymatic conversion of inorganic arsenic to mono- and dimethylated species has been considered a major mechanism for detoxification of inorganic arsenic. However, compelling experimental evidence obtained from several laboratories suggests that biomethylation, particularly the production of methylated metabolites that contain trivalent arsenic, is a process that activates arsenic as a toxin and a carcinogen. This article summarizes this evidence and provides new data on a) the toxicity of methylated trivalent arsenicals in mammalian cells, b) the effects of methylated trivalent arsenicals on gene transcription, and c) the mechanisms involved in arsenic methylation in animal and human tissues

The prolate-to-oblate shape transition of phospholipid vesicles in response to frequency variation of an AC electric field can be explained by the dielectric anisotropy of a phospholipid bilayer

The external electric field deforms flaccid phospholipid vesicles into spheroidal bodies, with the rotational axis aligned with its direction. Deformation is frequency dependent: in the low frequency range (~ 1 kHz), the deformation is typically prolate, while increasing the frequency to the 10 kHz range changes the deformation to oblate. We attempt to explain this behaviour with a theoretical model, based on the minimization of the total free energy of the vesicle. The energy terms taken into account include the membrane bending energy and the energy of the electric field. The latter is calculated from the electric field via the Maxwell stress tensor, where the membrane is modelled as anisotropic lossy dielectric. Vesicle deformation in response to varying frequency is calculated numerically. Using a series expansion, we also derive a simplified expression for the deformation, which retains the frequency dependence of the exact expression and may provide a better substitute for the series expansion used by Winterhalter and Helfrich, which was found to be valid only in the limit of low frequencies. The model with the anisotropic membrane permittivity imposes two constraints on the values of material constants: tangential component of dielectric permittivity tensor of the phospholipid membrane must exceed its radial component by approximately a factor of 3; and the membrane conductivity has to be relatively high, approximately one tenth of the conductivity of the external aqueous medium.Comment: 17 pages, 6 figures; accepted for publication in J. Phys.: Condens. Matte

Chronic Arsenic Exposure and Oxidative Stress: OGG1 Expression and Arsenic Exposure, Nail Selenium, and Skin Hyperkeratosis in Inner Mongolia

Arsenic, a human carcinogen, is known to induce oxidative damage to DNA. In this study we investigated oxidative stress and As exposure by determining gene expression of OGG1, which codes for an enzyme, 8-oxoguanine DNA glycosylase, involved in removing 8-oxoguanine in As-exposed individuals. Bayingnormen (Ba Men) residents in Inner Mongolia are chronically exposed to As via drinking water. Water, toenail, and blood samples were collected from 299 Ba Men residents exposed to 0.34–826 μg/L As. RNA was isolated from blood, and mRNA levels of OGG1 were determined using real-time polymerase chain reaction. OGG1 expression levels were linked to As concentrations in drinking water and nails, selenium concentrations in nails, and skin hyperkeratosis. OGG1 expression was strongly associated with water As concentrations (p < 0.0001). Addition of the quadratic term significantly improved the fit compared with the linear model (p = 0.05). The maximal OGG1 response was at the water As concentration of 149 μg/L. OGG1 expression was also significantly associated with toenail As concentrations (p = 0.015) but inversely associated with nail Se concentrations (p = 0.0095). We found no significant differences in the As-induced OGG1 expression due to sex, smoking, or age even though the oldest group showed the strongest OGG1 response (p = 0.0001). OGG1 expression showed a dose-dependent increased risk of skin hyperkeratosis in males (trend analysis, p = 0.02), but the trend was not statistically significant in females. The results from this study provide a linkage between oxidative stress and As exposure in humans. OGG1 expression may be useful as a biomarker for assessing oxidative stress from As exposure

Pharmacokinetic characteristics and anticancer effects of 5-Fluorouracil loaded nanoparticles

<p>Abstract</p> <p>Background</p> <p>It is expected that prolonged circulation of anticancer drugs will increase their anticancer activity while decreasing their toxic side effects. The purpose of this study was to prepare 5-fluorouracil (5-FU) loaded block copolymers, with poly(γ-benzyl-L-glutamate) (PBLG) as the hydrophobic block and poly(ethylene glycol) (PEG) as the hydrophilic block, and then examine the 5-FU release characteristics, pharmacokinetics, and anticancer effects of this novel compound.</p> <p>Methods</p> <p>5-FU loaded PEG-PBLG (5-FU/PEG-PBLG) nanoparticles were prepared by dialysis and then scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe the shape and size of the nanoparticles, and ultraviolet spectrophotometry was used to evaluate the 5-FU in vitro release characteristics. The pharmacokinetic parameters of 5-FU/PEG-PBLG nanoparticles in rabbit plasma were determined by measuring the 5-FUby high-performance liquid chromatography (HPLC). To study in vivo effects, LoVo cells (human colon cancer cell line) or Tca8113 cells (human oral squamous cell carcinoma cell line) were implanted in BALB/c nude mice that were subsequently treated with 5-FU or 5-FU/PEG-PBLG nanospheres.</p> <p>Results</p> <p>5-FU/PEG-PBLG nanoparticles had a core-shell spherical structure with a diameter of 200 nm and a shell thickness of 30 nm. The drug loading capacity was 27.1% and the drug encapsulation was 61.5%. Compared with 5-FU, 5-FU/PEG-PBLG nanoparticles had a longer elimination half-life (t_1/2, 33.3 h vs. 5 min), lower peak concentration (C, 4563.5 μg/L vs. 17047.3 μg/L), and greater distribution volume (V_D, 0.114 L vs. 0.069 L). Compared with a blank control, LoVo cell xenografts and Tca8113 cell xenografts treated with 5-FU or 5-FU/PEG-PBLG nanoparticles grew slower and had prolonged tumor doubling times. 5-FU/PEG-PBLG nanoparticles showed greater inhibition of tumor growth than 5-FU (p < 0.01). In the PEG-PBLG nanoparticle control group, there was no tumor inhibition (p > 0.05).</p> <p>Conclusion</p> <p>In our model system, 5-FU/PEG-PBLG nanoparticles changed the pharmacokinetic behavior of 5-FU, thus increasing its anticancer activity. 5-Fluorouracil loaded nanoparticles have potential as a novel anticancer drug that may have useful clinical applications.</p

Chronic Intestinal Failure in Children: An International Multicenter Cross-Sectional Survey

Background: The European Society for Clinical Nutrition and Metabolism database for chronic intestinal failure (CIF) was analyzed to investigate factors associated with nutritional status and the intravenous supplementation (IVS) dependency in children. Methods: Data collected: demographics, CIF mechanism, home parenteral nutrition program, z-scores of weight-for-age (WFA), length or height-for-age (LFA/HFA), and body mass index-for-age (BMI-FA). IVS dependency was calculated as the ratio of daily total IVS energy over estimated resting energy expenditure (%IVSE/REE). Results: Five hundred and fifty-eight patients were included, 57.2% of whom were male. CIF mechanisms at age 1–4 and 14–18 years, respectively: SBS 63.3%, 37.9%; dysmotility or mucosal disease: 36.7%, 62.1%. One-third had WFA and/or LFA/HFA z-scores &lt; −2. One-third had %IVSE/REE &gt; 125%. Multivariate analysis showed that mechanism of CIF was associated with WFA and/or LFA/HFA z-scores (negatively with mucosal disease) and %IVSE/REE (higher for dysmotility and lower in SBS with colon in continuity), while z-scores were negatively associated with %IVSE/REE. Conclusions: The main mechanism of CIF at young age was short bowel syndrome (SBS), whereas most patients facing adulthood had intestinal dysmotility or mucosal disease. One-third were underweight or stunted and had high IVS dependency. Considering that IVS dependency was associated with both CIF mechanisms and nutritional status, IVS dependency is suggested as a potential marker for CIF severity in children