Relationship between sensorial and physical characteristics of topical creams: A comparative study on effects of excipients.

Rising consumer demands for safer, more natural, and sustainable topical products have led to increased interest in finding alternative excipients, while retaining functionality and cosmetic appeal. Particle-stabilized Pickering creams have emerged as possible alternatives to replace traditional surfactant-stabilized creams and are thus one of the focuses in this study. The aim of this paper was to study relationships between sensorial characteristics and physical properties to understand how different excipients affect these aspects, comparing one starch particle-stabilized and three surfactant-stabilized formulations. A human panel was used to evaluate sensorial perception, while physical properties were deduced by rheology and tactile friction, together with in vivo and ex vivo skin hydration measurements. The results show that sensorial attributes related to the application phase can be predicted with rheology, while afterfeel attributes can be predicted with tactile friction studies. Differences in rheological and sensory properties among surfactant-based creams could mainly be attributed to the type of emollients used, presence of thickeners and surfactant composition. Differences between surfactant-based creams and a Pickering cream were more evident in relation to the afterfeel perception. Presence of starch particles in the residual film on skin results in high tactile friction and low perception of residual coating, stickiness, greasiness, and slipperiness in sensorial afterfeel.

Dynamics and statics of DNA-programmable nanoparticle self-assembly and crystallization.

DNA linker mediated self-assembly is emerging as a very general strategy for designing new materials. In this Letter, we characterize both the dynamics and thermodynamics of nanoparticle-DNA self-assembly by molecular dynamics simulations from a new coarse-grained model. We establish the general phase diagram and discuss the stability of a previously overlooked crystalline phase (D-bcc). We also characterize universal properties about the dynamics of crystallization. We point out the connection to f-star polymer systems and discuss the implications for ongoing experiments as well as for the general field of DNA mediated self-assembly.

Relative quantitative RT-PCR to study the expression of plant nutrient transporters in arbuscular mycorrhizas.

The influence of arbuscular mycorrhizal fungi (AMF) on the expression of plant nutrient transporters was studied using a relative, quantitative reverse-transcription polymerase chain-reaction (RQRT-PCR) technique. Reverse-transcribed 18S rRNA was used to standardize the treatments. The technique had high reproducibility and reflected trends in gene expression as observed by Northern blotting. Using this technique, it was demonstrated that both the high-affinity phosphate transporter MtPt2 and a putative nitrate transporter from Medicago truncatula were down-regulated in roots when colonized by some, but not all AMF. Colonization by the AMF Glomus rosea, in particular, failed to strongly down-regulate these plant genes within the root. This technique may be suitable for the study of plant genes in mycorrhizal roots when Northern blotting is not possible due to low gene expression or when limited amounts of tissue are available for study.

Transformation of Medicago truncatula via infiltration of seedlings or flowering plants with Agrobacterium.

Two rapid and simple in planta transformation methods have been developed for the model legume Medicago truncatula. The first approach is based on a method developed for transformation of Arabidopsis thaliana and involves infiltration of flowering plants with a suspension of Agrobacterium. The second method involves infiltration of young seedlings with Agrobacterium. In both cases a proportion of the progeny of the infiltrated plants is transformed. The transformation frequency ranges from 4.7 to 76% for the flower infiltration method, and from 2.9 to 27.6% for the seedling infiltration method. Both procedures resulted in a mixture of independent transformants and sibling transformants. The transformants were genetically stable, and analysis of the T2 generation indicates that the transgenes are inherited in a Mendelian fashion. These transformation systems will increase the utility of M. truncatula as a model system and enable large-scale insertional mutagenesis. T-DNA tagging and the many adaptations of this approach provide a wide range of opportunities for the analysis of the unique aspects of legumes.

The down-regulation of Mt4-like genes by phosphate fertilization occurs systemically and involves phosphate translocation to the shoots.

Mt4 is a cDNA representing a phosphate-starvation-inducible gene from Medicago truncatula that is down-regulated in roots in response to inorganic phosphate (Pi) fertilization and colonization by arbuscular mycorrhizal fungi. Split-root experiments revealed that the expression of the Mt4 gene in M. truncatula roots is down-regulated systemically by both Pi fertilization and colonization by arbuscular mycorrhizal fungi. A comparison of Pi levels in these tissues suggested that this systemic down-regulation is not caused by Pi accumulation. Using a 30-bp region of the Mt4 gene as a probe, Pi-starvation-inducible Mt4-like genes were detected in Arabidopsis and soybean (Glycine max L.), but not in corn (Zea mays L.). Analysis of the expression of the Mt4-like Arabidopsis gene, At4, in wild-type Arabidopsis and pho1, a mutant unable to load Pi into the xylem, suggests that Pi must first be translocated to the shoot for down-regulation to occur. The data from the pho1 and split-root studies are consistent with the presence of a translocatable shoot factor responsible for mediating the systemic down-regulation of Mt4-like genes in roots.

Characterization of the Mt4 gene from Medicago truncatula.

Previously we identified Mt4, a phosphate starvation inducible cDNA from Medicago truncatula which is down-regulated in roots in response to phosphate fertilization as well as colonization by arbuscular mycorrhizal (AM) fungi (AM). Here we present further studies of Mt4. Expression was highly sensitive to exogenous applications of phosphate fertilizer; transcripts were abundant in roots fertilized with nutrient solution lacking phosphate, reduced when fertilized with 0.02 or 0.1 mM phosphate and undetectable when fertilized with 1 or 5 mM phosphate. A time course experiment, to study the expression of Mt4 following colonization by AM fungi, revealed that Mt4 transcripts increased in uncolonized roots during the first three weeks of growth and then plateaued, while transcript levels in roots colonized with the AM fungus, Glomas versiforme, increased transiently and then decreased. Although the Mt4 gene is expressed exclusively in roots, transcripts were also detected in M. truncatula cell suspension cultures following phosphate starvation. A genomic clone containing the Mt4 gene and 1133 bp of the 5' flanking sequence was identified from a M. truncatula genomic library. The promoter region contains a conserved cis-element found in the promoters of phosphate starvation inducible genes of yeast and tomato. As Mt4 is the first cDNA reported to show independent regulation by both phosphate and mycorrhizal fungi, the genomic clone may provide a starting point from which to analyze the signal transduction pathways involved in these two processes.

Community integration and life satisfaction after traumatic brain injury: long-term findings.

OBJECTIVE: This study examines the relationship of the degree of community integration to the life satisfaction of persons with traumatic brain injury (TBI). METHOD: The responses to two self-administered questionnaires measuring aspects of community integration and life satisfaction were studied for 30 persons with TBI who were 26 to 60 years of age. RESULTS: A significant relationship (rho = .37, p < .05) was found between life satisfaction and social integration (a component of community integration). No significant association was found between the total community integration score and life satisfaction. CONCLUSION: The results suggest the need for rehabilitation programs to provide long-term assistance with community-based social integration as well as more effective treatment strategies to develop these skills in persons with TBI.

A novel gene whose expression in Medicago truncatula roots is suppressed in response to colonization by vesicular-arbuscular mycorrhizal (VAM) fungi and to phosphate nutrition.

A cDNA clone (Mt4) was isolated as a result of a differential screen to identify genes showing altered expression during the interaction between Medicago truncatula and the vesicular-arbuscular mycorrhizal (VAM) fungus Glomus versiforme. Mt4 represents a M. truncatula mRNA that contains numerous short open reading frames, the two longest of which are predicted to encode polypeptides of 51 amino acids each. One of these open reading frames shares a short region of identity with a phosphate starvation-inducible gene from tomato. Mt4 gene expression is regulated in response to colonization by mycorrhizal fungi: transcripts were detected in non-colonized roots and levels decreased in both M. truncatula and M. sativa (alfalfa) roots after colonization by G. versiforme. Transcript levels also decreased during the incomplete interaction between G. versiforme and a M. sativa mycorrhizal minus (myc-) line, indicating that the down-regulation of this gene occurs early during the interaction between the fungus and its host plant. Phosphate levels in the nutrient media also affected the expression of the Mt4 gene: transcripts were present in the roots of plants grown under phosphate-deficient conditions, but were undetectable in the roots of plants grown under phosphate sufficient conditions. Furthermore, expression was only observed when plants were grown under nitrogen-sufficient conditions. Northern blot analyses indicate that Mt4 transcripts are present primarily in roots and barely detectable in stems or leaves. Thus, Mt4 represents a M. truncatula gene whose expression is regulated in response to both colonization by mycorrhizal fungi and to the phosphate status of the plant.