Screening mammography beliefs and recommendations: a web-based survey of primary care physicians

<p>Abstract</p> <p>Background</p> <p>The appropriateness and cost-effectiveness of screening mammography (SM) for women younger than 50 and older than 74 years is debated in the clinical research community, among health care providers, and by the American public. This study explored primary care physicians' (PCPs) perceptions of the influence of clinical practice guidelines for SM; the recommendations for SM in response to hypothetical case scenarios; and the factors associated with perceived SM effectiveness and recommendations in the US from June to December 2009 before the United States Preventive Services Task Force (USPSTF) recently revised guidelines.</p> <p>Methods</p> <p>A nationally representative sample of 11,922 PCPs was surveyed using a web-based questionnaire. The response rate was 5.7% (684); (41%) 271 family physicians (FP), (36%) 232 general internal medicine physicians (IM), (23%) 150 obstetrician-gynaecologists (OBG), and (0.2%) 31 others. Cross-sectional analysis examined PCPs perceived effectiveness of SM, and recommendation for SM in response to hypothetical case scenarios. PCPs responses were measured using 4-5 point adjectival scales. Differences in perceived effectiveness and recommendations for SM were examined after adjusting for PCPs specialty, race/ethnicity, and the US region.</p> <p>Results</p> <p>Compared to IM and FP, OBG considered SM more effective in reducing breast cancer mortality among women aged 40-49 years (<it>p </it>= 0.003). Physicians consistently recommended mammography to women aged 50-69 years with no differences by specialty (<it>p </it>= 0.11). However, 94% of OBG "always recommended" SM to younger and 86% of older women compared to 81% and 67% for IM and 84% and 59% for FP respectively (<it>p = </it>< .001). In ordinal regression analysis, OBG specialty was a significant predictor for perceived higher SM effectiveness and recommendations for younger and older women. In evaluating hypothetical scenarios, overall PCPs would recommend SM for the 80 year woman with CHF with a significant variation by specialty (38% of OBG, 18% of FP, 17% of IM; <it>p </it>= < .001).</p> <p>Conclusions</p> <p>A majority of physicians, especially OBG, favour aggressive breast cancer screening for women from 40 through 79 years of age, including women with short life expectancy. Policy interventions should focus on educating providers to provide tailored recommendations for mammography based on individualized cancer risk, health status, and preferences.</p

A Biobrick Library for Cloning Custom Eukaryotic Plasmids

Researchers often require customised variations of plasmids that are not commercially available. Here we demonstrate the applicability and versatility of standard synthetic biological parts (biobricks) to build custom plasmids. For this purpose we have built a collection of 52 parts that include multiple cloning sites (MCS) and common protein tags, protein reporters and selection markers, amongst others. Importantly, most of the parts are designed in a format to allow fusions that maintain the reading frame. We illustrate the collection by building several model contructs, including concatemers of protein binding-site motifs, and a variety of plasmids for eukaryotic stable cloning and chromosomal insertion. For example, in 3 biobrick iterations, we make a cerulean-reporter plasmid for cloning fluorescent protein fusions. Furthermore, we use the collection to implement a recombinase-mediated DNA insertion (RMDI), allowing chromosomal site-directed exchange of genes. By making one recipient stable cell line, many standardised cell lines can subsequently be generated, by fluorescent fusion-gene exchange. We propose that this biobrick collection may be distributed peer-to-peer as a stand-alone library, in addition to its distribution through the Registry of Standard Biological Parts (http://partsregistry.org/)

Aβ Mediated Diminution of MTT Reduction—An Artefact of Single Cell Culture?

The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazoliumbromide (MTT) reduction assay is a frequently used and easily reproducible method to measure beta-amyloid (Aβ) toxicity in different types of single cell culture. To our knowledge, the influence of Aβ on MTT reduction has never been tested in more complex tissue. Initially, we reproduced the disturbed MTT reduction in neuron and astroglia primary cell cultures from rats as well as in the BV2 microglia cell line, utilizing four different Aβ species, namely freshly dissolved Aβ (25-35), fibrillar Aβ (1-40), oligomeric Aβ (1-42) and oligomeric Aβ (1-40). In contrast to the findings in single cell cultures, none of these Aβ species altered MTT reduction in rat organotypic hippocampal slice cultures (OHC). Moreover, application of Aβ to acutely isolated hippocampal slices from adult rats and in vivo intracerebroventricular injection of Aβ also did not influence the MTT reduction in the respective tissue. Failure of Aβ penetration into the tissue cannot explain the differences between single cells and the more complex brain tissue. Thus electrophysiological investigations disclosed an impairment of long-term potentiation (LTP) in the CA1 region of hippocampal slices from rat by application of oligomeric Aβ (1-40), but not by freshly dissolved Aβ (25-35) or fibrillar Aβ (1-40). In conclusion, the experiments revealed a glaring discrepancy between single cell cultures and complex brain tissue regarding the effect of different Aβ species on MTT reduction. Particularly, the differential effect of oligomeric versus other Aβ forms on LTP was not reflected in the MTT reduction assay. This may indicate that the Aβ oligomer effect on synaptic function reflected by LTP impairment precedes changes in formazane formation rate or that cells embedded in a more natural environment in the tissue are less susceptible to damage by Aβ, raising cautions against the consideration of single cell MTT reduction activity as a reliable assay in Alzheimer's drug discovery studies

Low-temperature pyrolysis and co-pyrolysis of Göynük oil shale and terebinth berries (Turkey) in an autoclave

Low-temperature pyrolysis of Turkish Göynük oil shale (GOS) and terebinth berries as individual objects and their dry and hydrous co-pyrolysis in a closed system, in an autoclave was studied. The effect of pyrolysis conditions (temperature and duration) on the yield of extracts (hexane and benzene), gas and organic residue was investigated. The composition of extracts was determined via thin layer chromatography. The yield of the extracts increased with the increase of pyrolysis temperature and duration, and its maximum attained 48.5% from the initial organic matter for GOS and 40% for berries. On the other hand, supercritical water also affected product yields and composition of extracts derived from both GOS and terebinth berries. The total yields of extracts from hydrous pyrolysis were 57.3% and 60.0% for GOS and berries, respectively. However, the extracts of hydrous pyrolysis contained more polar heterocompounds and less nonaromatic hydrocarbons than those of dry pyrolysis. Addition of berries to GOS lowered the co-pyrolysis temperature about 10 °C for reaching the maximum yield of the total extract. Dry co-pyrolysis of GOS with berries resulted in additive rather than in synergistic effect in the total extract yield, but the composition of the extract as a fuel - more nonaromatic hydrocarbons (33.8%) and less heterocompounds (43.0%) than that of extracts from individual feedstocks - was improved. Similarly, in the case of hydrous co-pyrolysis, the yields of extracts (hexane and benzene), gas and organic residue consisted of partial contributions of the yields from the initial feedstocks. © 2011 Estonian Academy Publishers

LOW-TEMPERATURE PYROLYSIS AND CO-PYROLYSIS OF GOYNUK OIL SHALE AND TEREBINTH BERRIES (TURKEY) IN AN AUTOCLAVE

WOS: 000299049700002Low-temperature pyrolysis of Turkish Goynuk oil shale (GOS) and terebinth berries as individual objects and their dry and hydrous co-pyrolysis in a closed system, in an autoclave was studied. The effect of pyrolysis conditions (temperature and duration) on the yield of extracts (hexane and benzene), gas and organic residue was investigated. The composition of extracts was determined via thin layer chromatography. The yield of the extracts increased with the increase of pyrolysis temperature and duration, and its maximum attained 48.5% from the initial organic matter for GOS and 40% for berries. On the other hand, supercritical water also affected product yields and composition of extracts derived from both GOS and terebinth berries. The total yields of extracts from hydrous pyrolysis were 57.3% and 60.0% for GOS and berries, respectively. However, the extracts of hydrous pyrolysis contained more polar heterocompounds and less nonaromatic hydrocarbons than those of dry pyrolysis. Addition of berries to GOS lowered the co-pyrolysis temperature about 10 C for reaching the maximum yield of the total extract. Dry co-pyrolysis of GOS with berries resulted in additive rather than in synergistic effect in the total extract yield, but the composition of the extract as a fuel - more nonaromatic hydrocarbons (33.8%) and less heterocompounds (43.0%) than that of extracts from individual feedstocks - was improved. Similarly, in the case of hydrous co-pyrolysis, the yields of extracts (hexane and benzene), gas and organic residue consisted of partial contributions of the yields from the initial feedstocks.Estonian Ministry of Education and ResearchMinistry of Education and Research, Estonia [SF0142722s06]The authors thank Estonian Ministry of Education and Research for financing the project SF0142722s06

Rejuvenation of nanoscale logic at NBTI-critical paths using evolutionary TPG

One of the main reliability concerns in the nanoscale logic is the time-dependent variation caused by Negative Bias Temperature Instability (NBTI). It increases the threshold voltage of pMOS transistors, which slows down signal propagation along the paths between flip-flops. As a consequence, NBTI may cause transient faults and, ultimately, permanent circuit functional failure. In this paper, we propose an innovative NBTI mitigation approach by rejuvenation of nanoscale logic along NBTI-critical paths. The method is based on hierarchical NBTI-critical paths identification and rejuvenation stimuli generation using an Evolutionary Algorithm. The rejuvenation stimuli are used to drive to the recovery phase the pMOS transistors that are the most significant for the NBTI-induced path delay. This rejuvenation procedure is to be applied to the circuit as an execution overhead at predefined periods. The proposed approach is aimed at extending the reliable lifetime of nanoelectronics. Experimental results are demonstrated by electrical simulations of an ALU circuit design

Rejuvenation of nanoscale logic at NBTI-critical paths using evolutionary TPG

One of the main reliability concerns in the nanoscale logic is the time-dependent variation caused by Negative Bias Temperature Instability (NBTI). It increases the threshold voltage of pMOS transistors, which slows down signal propagation along the paths between flip-flops. As a consequence, NBTI may cause transient faults and, ultimately, permanent circuit functional failure. In this paper, we propose an innovative NBTI mitigation approach by rejuvenation of nanoscale logic along NBTI-critical paths. The method is based on hierarchical NBTI-critical paths identification and rejuvenation stimuli generation using an Evolutionary Algorithm. The rejuvenation stimuli are used to drive to the recovery phase the pMOS transistors that are the most significant for the NBTI-induced path delay. This rejuvenation procedure is to be applied to the circuit as an execution overhead at predefined periods. The proposed approach is aimed at extending the reliable lifetime of nanoelectronics. Experimental results are demonstrated by electrical simulations of an ALU circuit design