A multiphase model for the cross‐linking of ultra‐high viscous alginate hydrogels

In this study, a model for the cross-linking of ultra-high viscous alginate hydrogels is provided. The model consists of four kinetic equations describing the process, including the local accumulation and the depletion of mobile alginate, cross-linked alginate and cross-linking cations. For an efficient simulation, finite difference schemes with predictor-corrector algorithms were implemente

Multiphoton microscopy for the investigation of dermal penetration of nanoparticle-borne drugs

Multiphoton microscopy of a dually fluorescence-labeled model system in excised human skin is employed for high resolution three dimensional visualization in order to study the release, accumulation and penetration properties of drugs released from nanoscale carrier particles in dermal administration. Polymer particles were covalently labeled with fluorescein while Texas Red as a drug-model was dissolved in the particle to be released to the formulation matrix. Single nanoparticles on skin could easily be localized and imaged with diffraction limited resolution. The temporal evolution of the fluorescent drug-model concentration in various skin compartments over more than five hours was investigated by multiphoton spectral imaging of the same area of the specimen. The three dimensional penetration profile of the drug-model in correlation with skin morphology and particle localization information are obtained by a multiple laser line excitation experiment. Multiphoton microscopy combined with spectral imaging was found to allow non invasive long term studies of particle-borne drug-model penetration into the skin with sub cellular resolution. By dual color labeling a clear discrimination between particle-bound and released drug-model was possible. The introduced technique was shown to be a powerful tool in revealing the dermal penetration properties and pathways of drugs and nanoscale drug vehicles on microscopic level

Deep Learning-Based Tracking of Multiple Objects in the Context of Farm Animal Ethology

Automatic detection and tracking of individual animals is important to enhance their welfare and to improve our understanding of their behaviour. Due to methodological difficulties, especially in the context of poultry tracking, it is a challenging task to automatically recognise and track individual animals. Those difficulties can be, for example, the similarity of animals of the same species which makes distinguishing between them harder, or sudden changes in their body shape which may happen due to putting on or spreading out the wings in a very short period of time. In this paper, an automatic poultry tracking algorithm is proposed. This algorithm is based on the well-known tracktor approach and tackles multi-object tracking by exploiting the regression head of the Faster R-CNN model to perform temporal realignment of object bounding boxes. Additionally, we use a multi-scale re-identification model to improve the re-association of the detected animals. For evaluating the performance of the proposed method in this study, a novel dataset consisting of seven image sequences that show chicks in an average pen farm in different stages of growth is used

High level of conservation between genes coding for the GAMYB transcription factor in barley (Hordeum vulgare L.) and bread wheat (Triticum aestivum L.) collections

The transcription factor GAMYB is involved in gibberellin signalling in cereal aleurone cells and in plant developmental processes. Nucleotide diversity of HvGAMYB and TaGAMYB was investigated in 155 barley (Hordeum vulgare) and 42 wheat (Triticum aestivum) accessions, respectively. Polymorphisms defined 18 haplotypes in the barley collection and 1, 7 and 3 haplotypes for the A, B, and D genomes of wheat, respectively. We found that (1) Hv- and TaGAMYB genes have identical structures. (2) Both genes show a high level of nucleotide identity (>95%) in the coding sequences and the distribution of polymorphisms is similar in both collections. At the protein level the functional domain is identical in both species. (3) GAMYB genes map to a syntenic position on chromosome 3. GAMYB genes are different in both collections with respect to the Tajima D statistic and linkage disequilibrium (LD). A moderate level of LD was observed in the barley collection. In wheat, LD is absolute between polymorphic sites, mostly located in the first intron, while it decays within the gene. Differences in Tajima D values might be due to a lower selection pressure on HvGAMYB, compared to its wheat orthologue. Altogether our results provide evidence that there have been only few evolutionary changes in Hv- and TaGAMYB. This confirms the close relationship between these species and also highlights the functional importance of this transcription factor

Genetic dissection of photoperiod response based on GWAS of pre-anthesis phase duration in spring barley

Heading time is a complex trait, and natural variation in photoperiod responses is a major factor controlling time to heading, adaptation and grain yield. In barley, previous heading time studies have been mainly conducted under field conditions to measure total days to heading. We followed a novel approach and studied the natural variation of time to heading in a world-wide spring barley collection (218 accessions), comprising of 95 photoperiod-sensitive (Ppd-H1) and 123 accessions with reduced photoperiod sensitivity (ppd-H1) to long-day (LD) through dissecting pre-anthesis development into four major stages and sub-phases. The study was conducted under greenhouse (GH) conditions (LD; 16/8 h; ∼20/∼16°C day/night). Genotyping was performed using a genome-wide high density 9K single nucleotide polymorphisms (SNPs) chip which assayed 7842 SNPs. We used the barley physical map to identify candidate genes underlying genome-wide association scans (GWAS). GWAS for pre-anthesis stages/sub-phases in each photoperiod group provided great power for partitioning genetic effects on floral initiation and heading time. In addition to major genes known to regulate heading time under field conditions, several novel QTL with medium to high effects, including new QTL having major effects on developmental stages/sub-phases were found to be associated in this study. For example, highly associated SNPs tagged the physical regions around HvCO1 (barley CONSTANS1) and BFL (BARLEY FLORICAULA/LEAFY) genes. Based upon our GWAS analysis, we propose a new genetic network model for each photoperiod group, which includes several newly identified genes, such as several HvCO-like genes, belonging to different heading time pathways in barley

Growth and structure of In0.5Ga0.5Sb quantum dots on GaP(001)

Stranski-Krastanov (SK) growth of In0.5Ga0.5Sb quantum dots (QDs) on GaP(001) by metalorganic vapor phase epitaxy is demonstrated. A thin GaAs interlayer prior to QD deposition enables QD nucleation. The impact of a short Sb-flush before supplying InGaSb is investigated. QD growth gets partially suppressed for GaAs interlayer thicknesses below 6 monolayers. QD densities vary from 5 × 109 to 2 × 1011 cm−2 depending on material deposition and Sb-flush time. When In0.5Ga0.5Sb growth is carried out without Sb-flush, the QD density is generally decreased, and up to 60% larger QDs are obtained

Evolutionary relationships among barley and <i>Arabidopsis</i> core circadian clock and clock-associated genes

The circadian clock regulates a multitude of plant developmental and metabolic processes. In crop species, it contributes significantly to plant performance and productivity and to the adaptation and geographical range over which crops can be grown. To understand the clock in barley and how it relates to the components in the Arabidopsis thaliana clock, we have performed a systematic analysis of core circadian clock and clock-associated genes in barley, Arabidopsis and another eight species including tomato, potato, a range of monocotyledonous species and the moss, Physcomitrella patens. We have identified orthologues and paralogues of Arabidopsis genes which are conserved in all species, monocot/dicot differences, species-specific differences and variation in gene copy number (e.g. gene duplications among the various species). We propose that the common ancestor of barley and Arabidopsis had two-thirds of the key clock components identified in Arabidopsis prior to the separation of the monocot/dicot groups. After this separation, multiple independent gene duplication events took place in both monocot and dicot ancestors. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00239-015-9665-0) contains supplementary material, which is available to authorized users