Segmented copolymers with polyesteramide units of uniform length: structure analysis

Segmented poly(ether esteramide) copolymers with short (M = 382) partially aromatic esteramide units of uniform length and segments of poly(tetramethylene oxide) (PTMO) have beem synthesized in the melt. The polymers show phase separation into two or three phases. The influence of the PTMO segment length on the following properties was studied: the Tg of the amorphous phase, the Tm of the crystalline PTMO and the melting and crystallization behaviour of the uniform polyesteramide units. Volume fraction and density of each phase were determined. The polyesteramide units crystallize in lamellar structures; their sizes were studied using WAXD and SAXS. The polymers were melt processed and their mechanical properties were investigated using dynamic mechanical thermal analysis (d.m.t.a.) and tensile tests. Polyesteramide crystallinity, crystalline structure and crystallite size were found to be almost independent of PTMO segment length. The decrease in hard-segment melting temperature with increasing PTMO segment length is explained as being due to a `solvent¿ effect of the soft phase. The copolymers crystallize very fast, and the modulus in the rubber region is essentially independent of temperature. The copolymers with long PTMO segments (M = 2000 and 2900) have a low glass transition temperature (¿65°C); the materials are very soft and have an elongation at break of over 1000%. The copolymer with the shortest PTMO segments (M = 250) has a glass transition temperature of 43°C and the material is hard at room temperature

A comparison between the morphology of semicrystalline polymer blends of poly(ε-caprolactone)/poly(vinyl methyl ether) and poly(ε-caprolactone)/(styrene-acrylonitrile)

The morphology of polymer blends of poly(ε-caprolactone) (PCL) and poly(vinyl methyl ether) (PVME) is compared with that of PCL and a random copolymer of styrene and acrylonitrile (SAN). The main objective is to determine the influence of the glass transition temperature of the amorphous component (Tg,a) on the morphology of the semicrystalline polymer blends. These blends represent the two extreme cases corresponding to Tc < Tg,a and Tc > Tg,a, where Tc is the crystallization temperature. The morphology of these blends, with PVME and SAN representing the amorphous components, have been studied by small angle X-ray scattering. For both blends the long period increases with the addition of amorphous polymer, which is a strong indication for an interlamellar morphology. D.s.c. experiments, including enthalpy relaxation, are used to investigate the crystallinity and the interphases. The overall amount of crystallinity in both blends decreases with increasing content of amorphous polymer. However, the fraction of PCL that crystallizes decreases in PCL/SAN and increases slightly in PCL/PVME. Apparently, the addition of the low Tg,a PVME improves the crystallization of PCL in accordance with a simple Gamblers Ruin Model type argument. The high Tg,a of SAN means this does not occur in PCL/SAN blends. Conventional d.s.c. experiments show an interphase of pure amorphous PCL in PCL/SAN blends and enthalpy relaxation experiments demonstrate its presence in PCL/PVME blends as well.

Daily physical activities of patients with chronic low back pain, assessed with accelerometry

Different theoretical models consider the development and maintenance of chronic low back pain have in common that they all predict changes in the daily activites, although the direction of change may differ between or within these models. The objective of the present study was to investigate these changes, using accelerometers to obtain a quantitative measure of the activity patters over the day

Pyramiding of Meloidogyne hapla resistance genes in potato does not result in an increase of resistance

High levels of resistance against Meloidogyne hapla have been identified in wild species of tuber-bearing potatoes, but only QTL with partial effects have been identified so far in back crosses with cultivated potato. This study was designed to test if pyramiding of two previously identified resistance genes, R Mh-tar and R Mh-chc A, will result in improved or even an absolute level of resistance. R Mh-tar and R Mh-chc A introgressed from the wild tuber-bearing potato species Solanum tarijense and Solanum chacoense were combined in a segregating diploid Solanum tuberosum population. With the aid of AFLP markers, descendants from this segregating population were classified into four groups, carrying no R gene, with only R Mh-tar , with only R Mh-chc A and a group with the pyramided R Mh-tar and R Mh-chc A. Upon inoculation with M. hapla isolate Bovensmilde, the group containing only R Mh-chc A showed a decline of 88% in average number of developed egg masses compared to the group without R Mh-chc A and R Mh-tar . The group of genotypes containing only R Mh-tar , but not R Mh-chc A, showed a decline of 55% in the number of developed egg masses compared to the group without R Mh-chc A and R Mh-tar . Unfortunately, the latter effect of R Mh-tar was not significant. The effect of both loci, R Mh-tar and R Mh-chc A combined, did not further reduce the number of egg masses compared to the level of R Mh-chc A alon

Towards F1 Hybrid Seed Potato Breeding

Compared to other major food crops, progress in potato yield as the result of breeding efforts is very slow. Genetic gains cannot be fixed in potato due to obligatory out-breeding. Overcoming inbreeding depression using diploid self-compatible clones should enable to replace the current method of out-breeding and clonal propagation into an F1 hybrid system with true seeds. This idea is not new, but has long been considered unrealistic. Severe inbreeding depression and self-incompatibility in diploid germplasm have hitherto blocked the development of inbred lines. Back-crossing with a homozygous progenitor with the Sli gene which inhibits gametophytic self-incompatibility gave self-compatible offspring from elite material from our diploid breeding programme. We demonstrate that homozygous fixation of donor alleles is possible, with simultaneous improvement of tuber shape and tuber size grading of the recipient inbred line. These results provide proof of principle for F1 hybrid potato breeding. The technical and economic perspectives are unprecedented as these will enable the development of new products with combinations of useful traits for all stakeholders in the potato chain. In addition, the hybrid’s seeds are produced by crossings, rendering the production and voluminous transport of potato seed tubers redundant as it can be replaced by direct sowing or the use of healthy mini-tubers, raised in greenhouses

Telemonitoring of daily activity and symptom behavior in patients with COPD

Objectives. This study investigated the activity behavior of patients with COPD in detail compared to asymptomatic controls, and the relationship between subjective and objective activities (awareness), and readiness to change activity behavior. Methods. Thirty-nine patients with COPD (66.0 years; FEV(1)% predicted: 44.9%) and 21 healthy controls (57.0 years) participated. Objective daily activity was assessed by accelerometry and expressed as amount of activity in counts per minute (cpm). Patients' baseline subjective activity and stage of change were assessed prior to measurements. Results. Mean daily activity in COPD patients was significantly lower compared to the healthy controls (864 ± 277 cpm versus 1162 ± 282 cpm, P < 0.001). COPD patients showed a temporary decrease in objective activities in the early afternoon. Objective and subjective activities were significantly moderately related and most patients (55.3%) were in the maintenance phase of the stages of change. Conclusions. COPD patients show a distinctive activity decrease in the early afternoon. COPD patients are moderately aware of their daily activity but regard themselves as physically active. Therefore, future telemedicine interventions might consider creating awareness of an active lifestyle and provide feedback that aims to increase and balance activity levels

Societal Costs of Late Blight in Potato and Prospects of Durable Resistance Through Cisgenic Modification

In the European Union almost 6 Mha of potatoes are grown representing a value of close to ¿6,000,000,000. Late blight caused by Phytophthora infestans causes annual losses (costs of control and damage) estimated at more than ¿1,000,000,000. Chemical control is under pressure as late blight becomes increasingly aggressive and there is societal resistance against the use of environmentally unfriendly chemicals. Breeding programmes have not been able to markedly increase the level of resistance of current potato varieties. New scientific approaches may yield genetically modified marker-free potato varieties (either trans- and/or cisgenic, the latter signifying the use of indigenous resistance genes) as improved variants of currently used varieties showing far greater levels of resistance. There are strong scientific investments needed to develop such improved varieties but these varieties will have great economic and environmental impact. Here we present an approach, based on (cisgenic) resistance genes that will enhance the impact. It consists of five themes: the detection of R-genes in the wild potato gene pool and their function related to the various aspects in the infection route and reproduction of the late blight causing pathogen; cloning of natural R-genes and transforming cassettes of single or multiple (cisgenic) R-genes into existing varieties with proven adaptation to improve their value for consumers; selection of true to the wild type and resistant genotypes with similar qualities as the original variety; spatial and temporal resistance management research of late blight of the cisgenic genetically modified (GM) varieties that contain different cassettes of R-genes to avoid breaking of resistance and reduce build-up of epidemics; communication and interaction with all relevant stakeholders in society and transparency in what research is doing. One of the main challenges is to explain the different nature and possible biological improvement and legislative repercussions of cisgenic GM-crops in comparison with transgenic GM-crops. It is important to realize that the present EU Directive 2001/18/EC on GM crops does not make a difference between trans- and cisgenes. These rules were developed when only transgenic GM plants were around. We present a case arguing for an updating and refinement of these rules in order to place cisgenic GM-crops in another class of GM-plants as has been done in the past with (induced) mutation breeding and the use of protoplast fusion between crossable species. Keywords Cisgenesis - Cloning - Communication - Late blight - Phytophthora infestans - Potato - Resistance management - Selection - Transformatio

Design and evaluation of a flexible web-based screening service for clinimetrics

Clinimetrics is gaining significance in health related and clinical disciplines. However, obtaining and accessing outcome measures in a flexible manner is an issue because of difficult-to-use programs, fixed instruments and poor access to tools and results. Hence, we developed and evaluated a novel Software-as-a-Service to create, share, conduct and manage clinical screenings and tests. The service supports a wide variety of screening instruments. These instruments can then be used in a wide variety of ways: online and offline; on smartphone, tablet and computer; guided by a professional, or self-assessed. Both tests and results can be managed and shared among peers and patients. New screenings can be designed based on standardized instruments or tailored to outcome measure requirements. The service, called ReQuest, was successfully implemented in multiple research projects. Evaluation results show good acceptance in elderly asked to use the system for self-assessments. Researchers who use the service to conduct and manage screenings, value (i) secure on-site storage, (ii) the flexibility in which they can create or reuse screenings and (iii) sharing screenings with others