On the energy fluxes of low-energy protons and positive ions in the earth's inner radiation zones

Energy fluxes of low energy protons and positive ions in earth inner radiation zon

Charge-exchange lifetimes for low-energy protons in the outer radiation zone and implications concerning the density of atomic hydrogen in the terrestrial exosphere

Proton intensities of outer radiation zone during magnetic stor

A Creative Approach to Promoting and Discussing Social Emotional Learning

Social emotional learning (SEL) is an important topic in education and a desired area of professional development for teachers. This conceptual essay offers a creative approach in promoting and discussing SEL through the use of haiku poetry. The tenets from the Collaborative for Academic, Social, and Emotional Learning (CASEL) framework were synthesized into key concepts and presented as haiku poems as a pedagogical exercise to increase awareness on SEL

Adjunct Faculty & Institutional Identity: Toward a Model for Acculturation

Institutions of higher education (IHEs) are charged with instilling institutional identity among all employees and this is particularly true for smaller Christian IHEs committed to the Great Commission. Following a case study of a recently dissolved institution, this article suggests that it may be worth the investment to effectively generate institutional identity among adjunct faculty even if doing so requires additional funding or capital. In this paper the authors draw on the tenets of organizational socialization theory coupled with a prescribed curriculum as a conceptual framework designed to generate institutional identity among adjunct faculty. The authors highlight a multi-phased model for implementing a sophisticated curriculum formulated to effectively cultivate institutional identity and discuss the benefits that are associated with enhanced onboarding efforts. It is suggested that Christian IHEs consider benefitting from the recommended approach

Photovoltaic Performance of Ultrasmall PbSe Quantum Dots

We investigated the effect of PbSe quantum dot size on the performance of Schottky solar cells made in an ITO/PEDOT/PbSe/aluminum structure, varying the PbSe nanoparticle diameter from 1 to 3 nm. In this highly confined regime, we find that the larger particle bandgap can lead to higher open-circuit voltages (~0.6 V), and thus an increase in overall efficiency compared to previously reported devices of this structure. To carry out this study, we modified existing synthesis methods to obtain ultrasmall PbSe nanocrystals with diameters as small as 1 nm, where the nanocrystal size is controlled by adjusting the growth temperature. As expected, we find that photocurrent decreases with size due to reduced absorption and increased recombination, but we also find that the open-circuit voltage begins to decrease for particles with diameters smaller than 2 nm, most likely due to reduced collection efficiency. Owing to this effect, we find peak performance for devices made with PbSe dots with a first exciton energy of ~1.6 eV (2.3 nm diameter), with a typical efficiency of 3.5%, and a champion device efficiency of 4.57%. Comparing the external quantum efficiency of our devices to an optical model reveals that the photocurrent is also strongly affected by the coherent interference in the thin film due to Fabry-Pérot cavity modes within the PbSe layer. Our results demonstrate that even in this simple device architecture, fine-tuning of the nanoparticle size can lead to substantial improvements in efficiency

Contributors to the November Issue/Notes

Notes by Leo L. Linck, Anthony M. Bernard, Richard F. Swisher, Charles G. Hasson, James H. Neu, William J. Syring, and John H. Verdonk

Contributors to the November Issue/Notes

Notes by Leo L. Linck, Anthony M. Bernard, Richard F. Swisher, Charles G. Hasson, James H. Neu, William J. Syring, and John H. Verdonk

Methylation and protein expression of DNA repair genes: association with chemotherapy exposure and survival in sporadic ovarian and peritoneal carcinomas

<p>Abstract</p> <p>Background</p> <p>DNA repair genes critically regulate the cellular response to chemotherapy and epigenetic regulation of these genes may be influenced by chemotherapy exposure. Restoration of BRCA1 and BRCA2 mediates resistance to platinum chemotherapy in recurrent BRCA1 and BRCA2 mutated hereditary ovarian carcinomas. We evaluated BRCA1, BRCA2, and MLH1 protein expression in 115 sporadic primary ovarian carcinomas, of which 31 had paired recurrent neoplasms collected after chemotherapy. Additionally, we assessed whether promoter methylation of BRCA1, MLH1 or FANCF influenced response to chemotherapy or explained alterations in protein expression after chemotherapy exposure.</p> <p>Results</p> <p>Of 115 primary sporadic ovarian carcinomas, 39 (34%) had low BRCA1 protein and 49 (42%) had low BRCA2 expression. BRCA1 and BRCA2 protein expression were highly concordant (p < 0.0001). MLH1 protein loss occurred in 28/115 (24%) primary neoplasms. BRCA1 protein loss in primary neoplasms was associated with better survival (p = 0.02 Log Rank test) and remained significant after accounting for either stage or age in a multivariate model (p = 0.04, Cox proportional hazards). In paired specimens, BRCA1 protein expression increased in 13/21 (62%) and BRCA2 protein expression increased in 15/21 (71%) of recurrent carcinomas with low or intermediate protein in the paired primary. In contrast MLH1 expression was rarely decreased in recurrent carcinomas (1/33, 3%). Similar frequencies of MLH1, BRCA1, and FANCF promoter methylation occurred in primary carcinomas without previous chemotherapy, after neoadjuvant chemotherapy, or in recurrent neoplasms.</p> <p>Conclusion</p> <p>Low BRCA1 expression in primary sporadic ovarian carcinoma is associated with prolonged survival. Recurrent ovarian carcinomas commonly have increased BRCA1 and/or BRCA2 protein expression post chemotherapy exposure which could mediate resistance to platinum based therapies. However, alterations in expression of these proteins after chemotherapy are not commonly mediated by promoter methylation, and other regulatory mechanisms are likely to contribute to these alterations.</p

Ar-40/Ar-39 Ages of Maskelynite Grains from ALHA 77005

We present Ar-40/Ar-39 measurements for twelve small (20-60 micro-g) maskelynite samples from the heavily shocked martian meteorite ALHA 77005. The reported modal composition for ALHA 77005 is 50-60% olivine (Fa28), 30-40% pyroxene (Wo5Fs23En72), approx.8% maskelynite (An53), and approx.2% opaques by volume [1]). The meteorite is usually classified as a lherzolite. Previous Studies - Ar-40/Ar-39 results from previous work display disturbed release spectra [2,3]. In study [2], Ar-40/Ar-39 measurements on a 52-mg whole-rock sample produced an extremely disturbed release spec-trum, with all calculated apparent ages > 1 Ga, (Fig. 1). In a subsequent study [3], a light and a dark phase were analyzed. A 2.3-mg sample of the light, relatively low-K phase produced a disturbed release spectrum. For the first 20% of the Ar-39(sub K), most of the apparent ages exceeded >1 Ga; the remaining 80% yielded ages between 0.3-0.5 Ga. The integrated age for this phase is 0.9 Ga

Evaluating mixture adsorption models using molecular simulation

The design of adsorption-based separation processes using novel adsorbents requires reliable data for the adsorption of fluid mixtures on candidate adsorbents. Due to the difficulty of generating sufficient data across possible operating conditions, process designs generally rely on interpolation of pure-component data using a model, most commonly ideal adsorbed solution theory (IAST), and related theories. There are many cases where IAST fails to provide an adequate description of mixture adsorption, usually due to the fact that practical adsorbents do not have uniform surfaces. We have evaluated the use of a segregated version of IAST, where competition is assumed to occur at isolated adsorption sites. This simple modification can provide the correct description of adsorption across a large range of pressures using ideal isotherm models. We also demonstrate the importance of identifying multiple sites even for weakly adsorbing components to provide the correct behavior at high pressure. © 2013 American Institute of Chemical Engineers