Sensitive determination of total particulate phosphorus and particulate inorganic phosphorus in seawater using liquid waveguide spectrophotometry

Determining the total particulate phosphorus (TPP) and particulate inorganic phosphorus (PIP) in oligotrophic oceanic water generally requires the filtration of a large amount of water sample. This paper describes methods that require small filtration volumes for determining the TPP and PIP concentrations. The methods were devised by validating or improving conventional sample processing and by applying highly sensitive liquid waveguide spectrophotometry to the measurements of oxidized or acid-extracted phosphate from TPP and PIP, respectively. The oxidation of TPP was performed by a chemical wet oxidation method using 3% potassium persulfate. The acid extraction of PIP was initially carried out based on the conventional extraction methodology, which requires 1 M HCl, followed by the procedure for decreasing acidity. While the conventional procedure for acid removal requires a ten-fold dilution of the 1 M HCl extract with purified water, the improved procedure proposed in this study uses 8 M NaOH solution for neutralizing 1 M HCl extract in order to reduce the dilution effect. An experiment for comparing the absorbances of the phosphate standard dissolved in 0.1 M HCl and of that dissolved in a neutralized solution [1 M HCl : 8 M NaOH = 8:1 (v:v)] exhibited a higher absorbance in the neutralized solution. This indicated that the improved procedure completely removed the acid effect, which reduces the sensitivity of the phosphate measurement. Application to an ultraoligotrophic water sample showed that the TPP concentration in a 1075 mL-filtered sample was 8.4 nM with a coefficient of variation (CV) of 4.3% and the PIP concentration in a 2300 mL-filtered sample was 1.3 nM with a CV of 6.1%. Based on the detection limit (3 nM) of the sensitive phosphate measurement and the ambient TPP and PIP concentrations of the ultraoligotrophic water, the minimum filtration volumes required for the detection of TPP and PIP were estimated to be 15 and 52 mL, respectively

Cross-cultural differences in the processing of non-verbal affective vocalizations by japanese and canadian listeners

The Montreal Affective Voices (MAVs) consist of a database of non-verbal affect bursts portrayed by Canadian actors, and high recognitions accuracies were observed in Canadian listeners. Whether listeners from other cultures would be as accurate is unclear. We tested for cross-cultural differences in perception of the MAVs: Japanese listeners were asked to rate the MAVs on several affective dimensions and ratings were compared to those obtained by Canadian listeners. Significant Group × Emotion interactions were observed for ratings of Intensity, Valence, and Arousal. Whereas Intensity and Valence ratings did not differ across cultural groups for sad and happy vocalizations, they were significantly less intense and less negative in Japanese listeners for angry, disgusted, and fearful vocalizations. Similarly, pleased vocalizations were rated as less intense and less positive by Japanese listeners. These results demonstrate important cross-cultural differences in affective perception not just of non-verbal vocalizations expressing positive affect (Sauter et al., 2010), but also of vocalizations expressing basic negative emotions

25 years of epidermal stem cell research.

This is a chronicle of concepts in the field of epidermal stem cell biology and a historic look at their development over time. The past 25 years have seen the evolution of epidermal stem cell science, from first fundamental studies to a sophisticated science. The study of epithelial stem cell biology was aided by the ability to visualize the distribution of stem cells and their progeny through lineage analysis studies. The excellent progress we have made in understanding epidermal stem cell biology is discussed in this article. The challenges we still face in understanding epidermal stem cells include defining molecular markers for stem and progenitor sub-populations, determining the locations and contributions of the different stem cell niches, and mapping regulatory pathways of epidermal stem cell proliferation and differentiation. However, our rapidly evolving understanding of epidermal stem cells has many potential uses that promise to translate into improved patient therapy

Rescuing key native traits in cultured dermal papilla cells for human hair regeneration

Introduction: The dermal papilla (DP) represents the major regulatory entity within the hair follicle (HF), inducing hair formation and growth through reciprocal interactions with epithelial cells. However, human DP cells rapidly lose their hair inductive ability when cultured in an epithelium-deficient environment. Objectives: To determine if the conditioned medium collected from interfollicular keratinocytes (KCs-CM) is capable of improving DP cell native properties and inductive phenotype. Methods:DP cells were cultured with KCs-CM both in 2D and 3D culture conditions (spheroids). Further, the hair-inductive capacity of DP cells precultured with KCs-CM was tested in a hair reconstitution assay, after co-grafting with human keratinocytes in nude mice. Results:We demonstrate that KCs-CM contributes to restore the inductivity of cultured human DP cells in a more effective mode than the conventional 3D-cultures. This is supported by the higher active alkaline phosphatase (ALP) levels in DP cells, the improved self-aggregative capacity and the reduced expression of α-SMA and the V1-isoform of versican. Moreover, DP cells cultured with KCs-CM displayed a secretome profile (VEGF, BMP2, TGF- β1, IL-6) that matches the one observed during anagen. KCs-CM also enhanced DP cell proliferation, while preventing cells to undergo morphological changes characteristic of high passage cells. In opposition, the amount of collagenous and non-collagenous proteins deposited by DP cells was lower in the presence of KCs-CM. The improvement in ALP activity was maintained in 3D spheroidal cultures, even after KCs-CM retrieval, being superior to the effect of the gold-standard culture conditions. Moreover, DP cells cultured with KCs-CM and grafted with human keratinocytes supported the formation of HF- and sebaceous gland-like structures in mice. Conclusion:The proposed strategy encourages future cell-based strategies for HF regeneration not only in the context of hair-associated disorders, but also in the management of wounds to aid in restoring critical skin regulatory appendages.he research reported in this publication was supported by FCT/ MCTES (Fundação para a Ciência e a Tecnologia/ Ministério da Ciência, Tecnologia, e Ensino Superior) through the PD/59/2013, PD/BD/113800/2015 (C. Abreu), CEECIND/00695/2017 (M. T. Cerqueira), IF/00347/2015 (R. Pirraco), IF/00945/2014 (A. P. Marques) and UIDB/50026/2020 grants. We thank Manuela Lago for her sup port on experimental assays and to Emanuel Rognoni and Simon Broad from King’s College London for their expert technical assis tance in the establishment of the in vivo chamber model in our group

Clonal Growth of Dermal Papilla Cells in Hydrogels Reveals Intrinsic Differences between Sox2-Positive and -Negative Cells In Vitro and In Vivo

In neonatal mouse skin, two types of dermal papilla (DP) are distinguished by Sox2 expression: CD133+Sox2+ DP are associated with guard/awl/auchene hairs, whereas CD133+Sox2− DP are associated with zigzag (ZZ) hairs. We describe a three-dimensional hydrogel culture system that supports clonal growth of CD133+Sox2+, CD133+Sox2−, and CD133−Sox2− (non-DP) neonatal dermal cells. All three cell populations formed spheres that expressed the DP markers alkaline phosphatase, α8 integrin, and CD133. Nevertheless, spheres formed by CD133− cells did not efficiently support hair follicle formation in skin reconstitution assays. In the presence of freshly isolated P2 dermal cells, CD133+Sox2+ and CD133+Sox2− spheres contributed to the DP of both AA and ZZ hairs. Hair type did not correlate with sphere size. Sox2 expression was maintained in culture, but not induced significantly in Sox2− cells in vitro or in vivo, suggesting that Sox2+ cells are a distinct cellular lineage. Although Sox2+ cells were least efficient at forming spheres, they had the greatest ability to contribute to DP and non-DP dermis in reconstituted skin. As the culture system supports clonal growth of DP cells and maintenance of distinct DP cell types, it will be useful for further analysis of intrinsic and extrinsic signals controlling DP function