The smallest space miners: principles of space biomining

As we aim to expand human presence in space, we need to find viable approaches to achieve independence from terrestrial resources. Space biomining of the Moon, Mars and asteroids has been indicated as one of the promising approaches to achieve in-situ resource utilization by the main space agencies. Structural and expensive metals, essential mineral nutrients, water, oxygen and volatiles could be potentially extracted from extraterrestrial regolith and rocks using microbial-based biotechnologies. The use of bioleaching microorganisms could also be applied to space bioremediation, recycling of waste and to reinforce regenerative life support systems. However, the science around space biomining is still young. Relevant differences between terrestrial and extraterrestrial conditions exist, including the rock types and ores available for mining, and a direct application of established terrestrial biomining techniques may not be a possibility. It is, therefore, necessary to invest in terrestrial and space-based research of specific methods for space applications to learn the effects of space conditions on biomining and bioremediation, expand our knowledge on organotrophic and community-based bioleaching mechanisms, as well as on anaerobic biomining, and investigate the use of synthetic biology to overcome limitations posed by the space environments

Effets de la frequence de nourrissage sur les parametres zootechniques et le taux de masculinisation des larves de la souche « Bresil » du tilapia du nil Oreochromis niloticus (Linnee, 1758) pendant et apres le traitement...

Full French Title: Effets de la frequence de nourrissage sur les parametres zootechniques et le taux de masculinisation des larves de la souche « Bresil » du tilapia du nil Oreochromis niloticus (Linnee, 1758) pendant et apres le traitement avec le 17- α -methyltestosterone En larviculture la survie et la croissance peuvent être influencées par divers paramètres parmi lesquels la fréquence d’alimentation. L’effet de ce paramètre sur les larves de la souche « Brésil » du tilapia du Nil Oreochromis niloticus au cours de la période de traitement (5, 6, 7 et 8 repas / jour) et post-traitement (3, 4, 5 et 6 repas / jour) avec le 17-α -méthyltestostérone a été testé. La durée de chacune des périodes a été de 21 jours. La ration quotidienne distribuée a été établie sur la base du poids moyen initial avec un taux d’alimentation de 50 % de la biomasse par jour, ce dernier a été ajusté chaque semaine en fonction de la croissance des poissons. Après les 21 jours de la période de traitement hormonale, les meilleures performances de croissance (411,33 ± 21,19 mg) ont été enregistrées chez les larves nourries 6 fois par jour. Les plus fortes croissances (1617,44 ± 90,34 mg) au cours de la période post-traitement ont été obtenues chez les alevins ayant reçu 5 repas par jour. Les fréquences de nourrissage de 6 et 5 repas quotidiens sont donc optimales respectivement en période de traitement et post- traitement avec le 17-α -méthyltestostérone. Concernant, le taux de masculinisation, les poissons nourris aux fréquences de 6, 7 et 8 repas par jour ont obtenues des valeurs similaires mais supérieurs (p-value < 0,05) à celle de la fréquence de 5 repas par jour. Ainsi, pour obtenir un pourcentage élevé de mâle lors de l’inversion hormonale du sexe chez le tilapia du Nil en milieu d’élevage, une fréquence d’au moins 6 repas par jour est recommandée. Mots clés: Oreochromis niloticus, fréquence d’alimentation, Post-traitement, larves, paramètres zootechniques English Title: Effects of feeding frequency on zootechnical parameters and masculinization rate of Oreochromis niloticus (Linnaeus, 1758) «Brazil» strain larvae during and after the treatment with 17-alpha-methyltestosterone English Abstract In larval culture the survival and growth can be influenced by various parameters of which the feeding frequency. The effect of this parameter on ‘’ Brazil ‘’ strain larvae of Nile tilapia Oreochromis niloticus during (5, 6, 7 and 8 meals / day) and after (3, 4, 5 and 6 meals / day) 17-α -methyltestosterone treatment, was tested. The duration of each period was 21 days. The daily ration distributed was 50% of the biomass during the first week. It was adjusted for total biomass at the end of each control fishery. After the 21 days of the hormonal treatment period, the best growth performances (411.33 ± 21.19 mg) were recorded in the larvae fed 6 times per day. The highest growth (1617.44 ± 90.34 mg) after treatment was obtained in fry fed 5 meals per day. The feeding frequencies of 6 and 5 daily meals are therefore optimal during treatment and aftertreatment with 17- α-methyltestosterone respectively. Concerning the masculinization rate, fish fed at the frequencies of 6, 7 and 8 meals per day obtained similar values but higher (p-value < 0.05) than the frequency of 5 meals per day. A feeding of at least 6 meals per day is recommended during the inversion of the sex in the larvae of the ‘’ Brazil ‘’ strain of Nile tilapia in breeding environment. Regarding the rate of masculinization, fish fed at frequencies of 6, 7 and 8 meals per day obtained similar but higher values (p-value < 0.05) than the frequency of 5 meals per day. Thus, to obtain a high percentage of males during the hormonal inversion of sex in the Nile tilapia in the rearing environment, a frequency of at least 6 meals per day is recommended. Keywords: Oreochromis niloticus, feeding frequency, post-treatment, larvae, zootechnical parameter

Pengembangan Perangkat Pembelajaran Matematika dengan Model Pembelajaran Berbasis Masalah pada Materi Kubus dan Balok untuk Siswa Kelas VIII Smp/mts

The background of this study is the restrict of mathematics learning instruments as supporting learning referring to 2013 Curriculum. This study aimed to develop mathematics learning instruments with problem based learning's model on cubes and cuboids for 8th grade SMP/MTs. Learning instruments in this study are syllabus, lesson plans, and student worksheet. This study method used is 4D model by Thiagarajan, Dorothy S. Semmel, and Melvyn I. Semmel that consist of define, design, development, and disseminate, but the study was limited only to development step. Based on the data analysis, it can be conclude that mathematics learning instruments is very valid with mean score of syllabus is 4,53, mean score of lesson plans is 4,26, and mean score of student worksheet is 4,21. This student worksheet has also reached the practical qualification with mean percentage of student responses is 97,33 on a small test group

Progress on lanthanide-based organic–inorganic hybrid phosphors

Research on organic–inorganic hybrid materials containing trivalent lanthanide ions (Ln3+) is a very active field that has rapidly shifted in the last couple of years to the development of eco-friendly, versatile and multifunctional systems, stimulated by the challenging requirements of technological applications spanning domains as diverse as optics, environment, energy, and biomedicine. This tutorial review offers a general overview of the myriad of advanced Ln3+-based organic–inorganic hybrid materials recently synthesised, which may be viewed as a major innovation in areas of phosphors, lighting, integrated optics and optical telecommunications, solar cells, and biomedicin

Minimal Algorithmic Information Loss Methods for Dimension Reduction, Feature Selection and Network Sparsification

We introduce a family of unsupervised, domain-free, and (asymptotically) model-independent algorithms based on the principles of algorithmic probability and information theory designed to minimize the loss of algorithmic information, including a lossless-compression-based lossy compression algorithm. The methods can select and coarse-grain data in an algorithmic-complexity fashion (without the use of popular compression algorithms) by collapsing regions that may procedurally be regenerated from a computable candidate model. We show that the method can preserve the salient properties of objects and perform dimension reduction, denoising, feature selection, and network sparsification. As validation case, we demonstrate that the method preserves all the graph-theoretic indices measured on a well-known set of synthetic and real-world networks of very different nature, ranging from degree distribution and clustering coefficient to edge betweenness and degree and eigenvector centralities, achieving equal or significantly better results than other data reduction and some of the leading network sparsification methods. The methods (InfoRank, MILS) can also be applied to applications such as image segmentation based on algorithmic probability.Comment: 23 pages in double column including Appendix, online implementation at http://complexitycalculator.com/MILS

Evidence of random magnetic anisotropy in ferrihydrite nanoparticles based on analysis of statistical distributions

We show that the magnetic anisotropy energy of antiferromagnetic ferrihydrite depends on the square root of the nanoparticles volume, using a method based on the analysis of statistical distributions. The size distribution was obtained by transmission electron microscopy, and the anisotropy energy distributions were obtained from ac magnetic susceptibility and magnetic relaxation. The square root dependence corresponds to random local anisotropy, whose average is given by its variance, and can be understood in terms of the recently proposed single phase homogeneous structure of ferrihydrite.Comment: 6 pages, 2 figure

Chitosan membranes containing micro or nano-size bioactive glass particles : evolution of biomineralization followed by in-situ dynamic mechanical analysis

A newfamilyofbiodegradablepolymer/bioactiveglass(BG)compositematerialshas emergedbasedontheavailabilityofnano-sizedbioactiveparticles.Suchnovelbiocompo- sites canhaveenhancedperformance,intermsofmechanicalpropertiesandbioactivity, and theycanbedesignedtobeusedinboneregenerationapproaches. In thiswork,membranesofchitosan(CTS)andchitosanwithbioactiveglass(BG)both micron andnanosizedparticles(CTS/mBG,CTS/nBG,respectively)werepreparedby solvent casting.Microstructuralandmechanicalpropertieswereevaluatedinorderto compare theeffectsoftheincorporationofmicro(mBG) andnano(nBG)particlesinthe chitosan matrix. In vitro bioactivity testswereperformedtocharacterizetheapatitelayer that isformedonthesurfaceofthematerialafterbeingimmersedinsimulatedbodyfluid (SBF). Thebiomineralizationprocessonthebiomaterialswasalsofollowedusingnon- conventionaldynamicmechanicalanalysis(DMA),bothonlineandoffline.InsuchDMA experiments,thechangeinthestoragemodulus, E0, andthelossfactor,tan d, were measured asafunctionoftheimmersiontimeinSBF.TheresultsdemonstratedthatCTS/ nBG membranespossessenhancedmechanicalpropertiesandhigherbioactivityin comparisonwiththeCTS/mBG membranes.SuchresultssuggestthepotentialofnBGfor the developmentofbioactivecompositesforboneregenerationapplications.This work was financially supported by Foundation for Science and Technology (FCT) by the projects PTDC/QUI/69263/2006, PTDC/CTM-BPC/112774/2009 and, through the scholarship SFRH/BD/64601/2009 granted to Sofia G. Caridade. The authors acknowledge Dr D. Mohn and Prof. W. Stark (Em Zurich) for providing the nBG particles used

Sterol 3β-glucosyltransferase biocatalysts with a range of selectivities, including selectivity for testosterone

The main objectives of this work were to characterise a range of purified recombinant sterol 3β-glucosyltransferases and show that rational sampling of the diversity that exists within sterol 3β-glucosyltransferase sequence space can result in a range of enzyme selectivities. In our study the catalytically active domain of the Saccharomyces cerevisiae 3β-glucosyltransferase was used to mine putative sterol 3β-glucosyltransferases from the databases. Selected diverse sequences were expressed in and purified from Escherichia coli and shown to have different selectivities for the 3β-hydroxysteroids ergosterol and cholesterol. Surprisingly, three enzymes were also selective for testosterone, a 17β-hydroxysteroid. This study therefore reports for the first time sterol 3β-glucosyltransferases with selectivity for both 3β- and 17β-hydroxysteroids and is also the first report of recombinant 3β-glucosyltransferases with selectivity for steroids with a hydroxyl group at positions other than C-3. These enzymes could therefore find utility in the pharmaceutical industry for the green synthesis of a range of glycosylated compounds of medicinal interest

Preparation of well-dispersed chitosan/alginate hollow multilayered microcapsules for enhanced cellular internalization

Hollow multilayered capsules have shown massive potential for being used in the biomedical and biotechnology fields, in applications such as cellular internalization, intracellular trafficking, drug delivery, or tissue engineering. In particular, hollow microcapsules, developed by resorting to porous calcium carbonate sacrificial templates, natural-origin building blocks and the prominent Layer-by-Layer (LbL) technology, have attracted increasing attention owing to their key features. However, these microcapsules revealed a great tendency to aggregate, which represents a major hurdle when aiming for cellular internalization and intracellular therapeutics delivery. Herein, we report the preparation of well-dispersed polysaccharide-based hollow multilayered microcapsules by combining the LbL technique with an optimized purification process. Cationic chitosan (CHT) and anionic alginate (ALG) were chosen as the marine origin polysaccharides due to their biocompatibility and structural similarity to the extracellular matrices of living tissues. Moreover, the inexpensive and highly versatile LbL technology was used to fabricate core-shell microparticles and hollow multilayered microcapsules, with precise control over their composition and physicochemical properties, by repeating the alternate deposition of both materials. The microcapsules' synthesis procedure was optimized to extensively reduce their natural aggregation tendency, as shown by the morphological analysis monitored by advanced microscopy techniques. The well-dispersed microcapsules showed an enhanced uptake by fibroblasts, opening new perspectives for cellular internalization.publishe