Anisotropy of Charge Transport in a Uniaxially Aligned and Chain‐Extended,High‐Mobility,Conjugated Polymer Semiconductor

Charge transport in the ribbon phase of poly(2,5‐bis(3‐alkylthiophen‐2‐yl)thieno[3,2‐b]thiophene) (PBTTT)—one of the most highly ordered, chain‐extended crystalline microstructures available in a conjugated polymer semiconductor—is studied. Ribbon‐phase PBTTT has previously been found not to exhibit high carrier mobilities, but it is shown here that field‐effect mobilities depend strongly on the device architecture and active interface. When devices are constructed such that the ribbon‐phase films are in contact with either a polymer gate dielectric or an SiO₂ gate dielectric modified by a hydrophobic, self‐assembled monolayer, high mobilities of up to 0.4 cm² V^?1 s^?1 can be achieved, which is comparable to those observed previously in terrace‐phase PBTTT. In uniaxially aligned, zone‐cast films of ribbon‐phase PBTTT the mobility anisotropy is measured for transport both parallel and perpendicular to the polymer chain direction. The mobility anisotropy is relatively small, with the mobility along the polymer chain direction being higher by a factor of 3–5, consistent with the grain size encountered in the two transport directions.     

Isogeometric finite element data structures based on Bézier extraction of T‐splines

We develop finite element data structures for T‐splines based on Bézier extraction generalizing our previous work for NURBS. As in traditional finite element analysis, the extracted Bézier elements are defined in terms of a fixed set of polynomial basis functions, the so‐called Bernstein basis. The Bézier elements may be processed in the same way as in a standard finite element computer program, utilizing exactly the same data processing arrays. In fact, only the shape function subroutine needs to be modified while all other aspects of a finite element program remain the same. A byproduct of the extraction process is the element extraction operator. This operator localizes the topological and global smoothness information to the element level, and represents a canonical treatment of T‐junctions, referred to as ‘hanging nodes’ in finite element analysis and a fundamental feature of T‐splines. A detailed example is presented to illustrate the ideas. Copyright © 2011 John Wiley & Sons, Ltd.     

A note on first-order projections and games

We show how the fact that there is a first-order projection from the problem transitive closure (TC) to some other problem Ω enables us to automatically deduce that a natural game problem, , whose instances are labelled instances of Ω, is complete for PSPACE (via log-space reductions). Our analysis is strongly dependent upon the reduction from TC to Ω being a logical projection in that it fails should the reduction be, for example, a log-space reduction or a quantifier-free first-order translation.     

Insect feeding and oviposition deterrents from western red cedar foliage

The feeding deterrent activity of fractions from the foliage of western red cedar,Thujaplicata Donn, was studied in laboratory bioassays using the white pine weevil,Pissodes strobi Peck, as a test insect. The most active fraction was the volatile mixture that comprises the leaf oil of this tree species. Further fractionation of the leaf oil indicated feeding deterrent activity in the monoterpene hydrocarbon, thujone, and terpene alcohol fractions. When tested alone, both (–)-3-isothujone and (+)-3-thujone, which made up 75–88% and 5–10% of the leaf oil, respectively, deterred feeding by the weevils. Western red cedar leaf oil also showed antifeedant activity with the alder flea beetle,Altica ambiens (Le Conte), and served as an oviposition deterrent for the onion root maggot,Hylemya antiqua Meigen. The leaf oil, however, had no inhibitory effect on the feeding of the leaf roller,Epinotia solandriana L., and the red-backed sawfly,Eriocampa ovata L.Research supported by the Natural Science and Engineering Research Council, Canada, Co-op Grant No. A0243 and Operating Grant Nos. A3881 and A3706, and by the British Columbia Ministry of Labour Youth Employment Program.     

Prognostic factors in metastatic melanoma

BACKGROUND: Each year, 6000 people die in the United States from metastatic melanoma. Further study of factors affecting the prognosis of patients with this disease is needed. METHODS: The authors analyzed response and survival data from 635 patients who had entered three Eastern Cooperative Oncology Group trials for metastatic melanoma. RESULTS: Factors associated with poorer survival after study entry included poor performance status and the presence of symptoms, such as reduced appetite, fever, or nausea/vomiting. Male patients had poor survival, as did patients entering the study less than 1 year after a documented recurrence to study entry. As expected, characteristics of the initial primary disease (treatment and symptoms) had little association with survival after entering the advanced disease protocol. Two summary measures of the extent of metastatic involvement had a strong influence on survival. These were the number of nonbone metastases and the clinician's assessment as to the most significant metastatic site. Patients with the liver as their clinically most significant metastatic site had a poorer prognosis than those otherwise classified, including those with central nervous system metastases. The prognosis also worsened with an increasing number of sites of nonbone metastases, including skin and soft tissue. Tumor response occurred in only 11% of the patients. Patients with poor performance status and those with lung involvement had a significantly lower response rate than did others. Although the frequency of response was low, patients with objective responses survived significantly longer than did the nonresponders (based on an analysis appropriately adjusted for the time of response using a time-dependent proportional-hazards model). CONCLUSIONS: These results provide useful guidelines for the design and analysis of clinical trials in metastatic melanoma.     

Effects of river flooding on PCDD/F and PCB levels in cows' milk, soil, and grass

This paper presents the results of a study examining whether the flooding of pasture by rivers gives rise to higher PCDD/F and PCB concentrations in cows' milk. Over 180 milk, soil, and grass samples, taken from 38 farms across 3 different river systems (River Dee, Trent, and Doe Lea/Rother/Don) in the United Kingdom, were analyzed for PCDD/Fs and PCBs. The concentrations were compared between flood-prone farms, where the animals had access to pasture that is often flooded, and control farms where the land does not flood. The results indicated that concentrations of PCDD/Fs and PCBs in cows' milk were higher in samples taken from farms prone to flooding, but only from the river systems flowing through industrial and urban areas. Raised levels of PCDD/F and PCBs were also found in soil and grass from farms prone to flooding providing strong corroborative evidence that the higher concentrations in cows' milk from such areas is likely to be due to the ingestion of contaminated grass and soil. Overall, the results provide strong evidence that flooding of pastureland can indeed result in elevated concentrations of PCDD/Fs and PCBs in milk from the farms so affected.     

Dose response modelling of Escherichia coli O157 incorporating data from foodborne and environmental outbreaks

A human dose response model for Escherichia coli O157 would enable prediction of risk of infection to humans following exposure from either foodborne or environmental pathways. However, due to the severe nature of the disease, volunteer human dose response studies cannot be carried out. Surrogate models from Shigella fed to humans and E. coli O157 to rabbits have been utilised but are significantly different to one another. In addition data obtained by animal exposure may not be representative for human beings. An alternative approach to generating and validating a dose response model is to use quantitative data obtained from actual human outbreaks. This work collates outbreak data obtained from global sources and these are fitted using exponential and beta-Poisson models. The best fitting model was found to be the beta-Poisson model using a beta-binomial likelihood and the authors favour the exact version of this model. The confidence levels in this model encompass a previously published Shigella dose response model. The potential incorporation of this model into QMRAs is discussed together with applications of the model to help explain foodborne outbreaks.     

Vesicoureteral reflux associated with intact orthotopic ureterocele

Two cases of vesicoureteral reflux into intact, orthotopic ureteroceles are described. A review of the literature failed to reveal any similar reports. Insufficient submucosal ureteral length was thought to be the cause in each of the cases. Both patients were satisfactorily managed with standard ureteroneocystostomy after resection of the ureterocele.     

Biological properties of recombinant alpha-interferons: 40th anniversary of the discovery of interferons

IFNs were first described as potent antiviral agents 40 years ago, and recombinant IFN-alpha2a and IFN-alpha2b were approved for the treatment of hairy cell leukemia just 11 years ago. Today, alpha-IFNs are approved worldwide for the treatment of a variety of malignancies and virologic diseases. Although the exact mechanism of action of IFN-alpha in the treatment of such diseases is not fully understood, many advances have been made in the characterization of the physicochemical and diverse biological properties of this highly pleiotropic cytokine. Here we review recent developments in our understanding of the antiviral and immunoregulatory properties of IFN-alpha, the nature of the multisubunit IFN-alpha receptor, and the molecular mechanisms of signal transduction. Where available, we have included comparative data on recombinant alpha-IFNs derived from both naturally occurring and nonnaturally occurring synthetic genes. We also review clinical data and data on the side effects and antigenicity of different sources of recombinant alpha-IFNs in humans. These latter topics are of clinical interest, because they may potentially affect the efficacy of these various products. Hopefully, what is already known about IFN will prompt further exploration into the mechanism(s) of action of IFN-alpha and thus deliver new applications for this prototypic cytokine, whose full therapeutic potential is yet to be realized.     

Energy Efficient Reliable Data Collection in Wireless Sensor Networks with Asymmetric Links

Field measurements reveal that radio link asymmetry has a severe impact on reliable data delivery. We analyze the energy efficiencies of selected reliability schemes for asymmetric radio links using theoretical models. The analysis provides guidelines for retransmission control so as to balance between reliability and energy consumption. We also design two enhancements to the “implicit” ARQ scheme addressing the negative effects of asymmetric radio links. The energy efficiencies of these algorithms are explicitly derived using our theoretical model and validated by simulations and field trials. Based on the analysis of the two enhanced algorithms, we propose an improvement, referred to as Energy Efficient Reliable Data Collection (EERDC) that controls the retransmissions of the enhanced ARQ schemes. Simulations and field trials confirm our theoretical findings and demonstrate that our proposed EERDC algorithm alleviates the impact of link asymmetry and achieves energy savings.