396 research outputs found
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Charge delocalization characteristics of regioregular high mobility polymers.
Controlling the regioregularity among the structural units of narrow bandgap conjugated polymer backbones has led to improvements in optoelectronic properties, for example in the mobilities observed in field effect transistor devices. To investigate how the regioregularity affects quantities relevant to hole transport, regioregular and regiorandom oligomers representative of polymeric structures were studied using density functional theory. Several structural and electronic characteristics of the oligomers were compared, including chain planarity, cation spin density, excess charges on molecular units and internal reorganizational energy. The main difference between the regioregular and regiorandom oligomers is found to be the conjugated backbone planarity, while the reorganizational energies calculated are quite similar across the molecular family. This work constitutes the first step on understanding the complex interplay of atomistic changes and an oligomer backbone structure toward modeling the charge transport properties
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Eau de Cleopatra: Mendesian perfume and Tell Timai
A combination of Classics, Egyptology, and experimental archaeology were utilized to recreate the (in)famous perfume used by Queen Cleopatra VII. Especially important was the use of classical sources and paleobotany to determine the identity of the Egyptian sacred oils such as camphor and balanos. Excavations at the site of Tell Timai revealed a perfumery that contributed to our ability to recreate the process of perfume manufacture. This ancient âMendesianâ perfume has since been recreated in the lab, exhibited at the Smithsonian, and worn again for the first time in millennia
Treatment of hallux valgus by modified McBride procedure: a 6-year follow-up
PubMed ID: 20505975Background Surgical decision-making was reevaluated by comparison with an algorithm designed to analyze treatment of hallux valgus deformities. Materials and methods A modified McBride procedure was performed on 52 feet of 35 patients with hallux valgusdeformity. From this series, 36 feet of 21 patients were evaluated preoperatively, early postoperatively, and late postoperatively by means of subjective evaluation and clinical and radiological findings. Results The hallux valgus angle preoperatively, early postoperatively, and late postoperatively was 32.7 ± 8.5°, 10.1 ± 6.9°, and 20.6 ± 9.5°, respectively. Hallux valgus recurrence of 72.2% was observed. Subjective results were better and the patients rated their satisfaction with the procedure as excellent or high in 23 cases (63.9%) and moderate, low, or unsatisfactory in 13 cases (36.1%). Conclusions This level of patient satisfaction demonstrates that the McBride procedure is an efficient approach for eliminating pain due to hallux valgus deformity. © The Author(s) 2010
Treatment of hallux valgus by modified McBride procedure: a 6-year follow-up
PubMed ID: 20505975Background Surgical decision-making was reevaluated by comparison with an algorithm designed to analyze treatment of hallux valgus deformities. Materials and methods A modified McBride procedure was performed on 52 feet of 35 patients with hallux valgusdeformity. From this series, 36 feet of 21 patients were evaluated preoperatively, early postoperatively, and late postoperatively by means of subjective evaluation and clinical and radiological findings. Results The hallux valgus angle preoperatively, early postoperatively, and late postoperatively was 32.7 ± 8.5°, 10.1 ± 6.9°, and 20.6 ± 9.5°, respectively. Hallux valgus recurrence of 72.2% was observed. Subjective results were better and the patients rated their satisfaction with the procedure as excellent or high in 23 cases (63.9%) and moderate, low, or unsatisfactory in 13 cases (36.1%). Conclusions This level of patient satisfaction demonstrates that the McBride procedure is an efficient approach for eliminating pain due to hallux valgus deformity. © The Author(s) 2010
Regulation of RasGRP1 Function in T Cell Development and Activation by Its Unique Tail Domain
The Ras-guanyl nucleotide exchange factor RasGRP1 plays a critical role in T cell receptor-mediated Erk activation. Previous studies have emphasized the importance of RasGRP1 in the positive selection of thymocytes, activation of T cells, and control of autoimmunity. RasGRP1 consists of a number of well-characterized domains, which it shares with its other family members; however, RasGRP1 also contains an âŒ200 residue-long tail domain, the function of which is unknown. To elucidate the physiological role of this domain, we generated knock-in mice expressing RasGRP1 without the tail domain. Further analysis of these knock-in mice showed that thymocytes lacking the tail domain of RasGRP1 underwent aberrant thymic selection and, following TCR stimulation, were unable to activate Erk. Furthermore, the deletion of the tail domain led to enhanced CD4+ T cell expansion in aged mice, as well as the production of autoantibodies. Mechanistically, the tail-deleted form of RasGRP1 was not able to traffic to the cell membrane following stimulation, indicating a potential reason for its inability to activate Erk. While the DAG-binding C1 domain of RasGRP1 has long been recognized as an important factor mediating Erk activation, we have revealed the physiological relevance of the tail domain in RasGRP1 function and control of Erk signaling
Planetary population synthesis
In stellar astrophysics, the technique of population synthesis has been
successfully used for several decades. For planets, it is in contrast still a
young method which only became important in recent years because of the rapid
increase of the number of known extrasolar planets, and the associated growth
of statistical observational constraints. With planetary population synthesis,
the theory of planet formation and evolution can be put to the test against
these constraints. In this review of planetary population synthesis, we first
briefly list key observational constraints. Then, the work flow in the method
and its two main components are presented, namely global end-to-end models that
predict planetary system properties directly from protoplanetary disk
properties and probability distributions for these initial conditions. An
overview of various population synthesis models in the literature is given. The
sub-models for the physical processes considered in global models are
described: the evolution of the protoplanetary disk, the planets' accretion of
solids and gas, orbital migration, and N-body interactions among concurrently
growing protoplanets. Next, typical population synthesis results are
illustrated in the form of new syntheses obtained with the latest generation of
the Bern model. Planetary formation tracks, the distribution of planets in the
mass-distance and radius-distance plane, the planetary mass function, and the
distributions of planetary radii, semimajor axes, and luminosities are shown,
linked to underlying physical processes, and compared with their observational
counterparts. We finish by highlighting the most important predictions made by
population synthesis models and discuss the lessons learned from these
predictions - both those later observationally confirmed and those rejected.Comment: 47 pages, 12 figures. Invited review accepted for publication in the
'Handbook of Exoplanets', planet formation section, section editor: Ralph
Pudritz, Springer reference works, Juan Antonio Belmonte and Hans Deeg, Ed
Ninety-Degree Chevron Osteotomy for Correction of Hallux Valgus Deformity: Clinical Data and Finite Element Analysis
Hallux valgus is a very common foot disorder, with its prevalence estimated at 33% in adult shoe-wearing populations. Conservative management is the initial treatment of choice for this condition, but surgery is sometimes needed. The 600 angle Chevron osteotomy is an accepted method for correction of mild to moderate hallux valgus in adults less than 60 years old. A modified 900 angle Chevron osteotomy has also been described; this modified technique can confer some advantages compared to the 600 angle method, and reported results are good. In the current work we present clinical data from a cohort of fifty-one female patients who had surgery for sixty-two hallux valgus deformities. In addition, in order to get a better physical insight and study the mechanical stresses along the two osteotomies, Finite Element Analysis (FEA) was also conducted. FEA indicated enhanced mechanical bonding with the modified 900 Chevron osteotomy, because the compressive stresses that keep the two bone parts together are stronger, and the shearing stresses that tend to slide the two bone parts apart are weaker, compared to the typical 600 technique. Follow-up data on our patient cohort show good or excellent long-term clinical results with the modified 900 angle technique. These results are consistent with the FEA-based hypothesis that a 900 Chevron osteotomy confers certain mechanical advantages compared to the typical 600 procedure
Simultaneous bilateral total ankle replacement using a 3-component prosthesis: Outcome in 26 patients followed for 2â10 years
Total ankle replacement is an established surgical procedure in patients with end-stage ankle osteoarthritis. We analyzed complications and medium-term results in patients with simultaneous bilateral total ankle replacement
The Role of Screenings Methods and Risk Profile Assessments in Prevention and Health Promotion Programmes: An Ethnographic Analysis
In prevention and health promotion interventions, screening methods and risk profile assessments are often used as tools for establishing the interventionsâ effectiveness, for the selection and determination of the health status of participants. The role these instruments fulfil in the creation of effectiveness and the effects these instruments have themselves remain unexplored. In this paper, we have analysed the role screening methods and risk profile assessments fulfil as part of prevention and health promotion programmes in the selection, enrolment and participation of participants. Our analysis showed, that screening methods and health risk assessments create effects as they objectify health risks and/or the health status of individuals, i.e., they select the individuals âat riskâ and indicate the lifestyle modifications these people are required to make in order to improve their health. Yet, these instruments also reduce the group of participants thereby decreasing the possible effect of interventions, as they provide the legitimisation for people to make choices to whether they enrol or not and what lifestyle changes they incorporate into their lives. In other words, they present a space of interaction, in which agency is distributed across the practice nurses, the participants and the instruments. Decisions were not just made upon the projection of the outcomes of these instruments; decisions that were made by both the patients and practice nurses were the resultant of their opinions on these outcomes that were formed in interaction with the instruments
PAR1 is selectively over expressed in high grade breast cancer patients: a cohort study
<p>Abstract</p> <p>Background</p> <p>The protease-activated receptor (PAR1) expression is correlated with the degree of invasiveness in cell lines. Nevertheless it has never been directed involved in breast cancer patients progression. The aim of this study was to determine whether PAR1 expression could be used as predictor of metastases and mortality.</p> <p>Methods</p> <p>In a cohort of patients with infiltrating ductal carcinoma studied longitudinally since 1996 and until 2007, PAR1 over-expression was assessed by immunoblotting, immunohistochemistry, and flow citometry. Chi-square and log rank tests were used to determine whether there was a statistical association between PAR1 overexpression and metastases, mortality, and survival. Multivariate analysis was performed including HER1, stage, ER and nodes status to evaluate PAR1 as an independent prognostic factor.</p> <p>Results</p> <p>Follow up was 95 months (range: 2â130 months). We assayed PAR1 in a cohort of patients composed of 136 patients; we found PAR1 expression assayed by immunoblotting was selectively associated with high grade patients (50 cases of the study cohort; P = 0.001). Twenty-nine of 50 (58%) patients overexpressed PAR1, and 23 of these (46%) developed metastases. HER1, stage, ER and PAR1 overexpression were robustly correlated (Cox regression, P = 0.002, P = 0.024 and P = 0.002 respectively). Twenty-one of the 50 patients (42%) expressed both receptors (PAR1 and HER1 P = 0.0004). We also found a statistically significant correlation between PAR1 overexpression and increased mortality (P = 0.0001) and development of metastases (P = 0.0009).</p> <p>Conclusion</p> <p>Our data suggest PAR1 overexpression may be involved in the development of metastases in breast cancer patient and is associated with undifferentiated cellular progression of the tumor. Further studies are needed to understand PAR1 mechanism of action and in a near future assay its potential use as risk factor for metastasis development in high grade breast cancer patients.</p
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