Differentiation of cartilaginous anlagen in entire embryonic mouse limbs cultured in a rotating bioreactor.

Mechanisms involved in development of the embryonic limb have remained the same throughout eons of genetic and environmental evolution under Earth gravity (1 g). During the spaceflight era it has been of interest to explore the ancient theory that form of the skeleton develops in response to gravity, and that changes in gravitational forces can change the developmental pattern of the limb. This has been shown in vivo and in vitro, allowing the hypergravity of centrifugation and microgravity of space to be used as tools to increase our knowledge of limb development. In recapitulations of spaceflight experiments, premetatarsals were cultured in suspension in a bioreactor, and found to be shorter and less differentiated than those cultured in standard culture dishes. This study only measured length of the metatarsals, and did not account for possible changes due to the skeletal elements having a more in vivo 3D shape while in suspension vs. flattened tissues compressed by their own weight. A culture system with an outcome closer to in vivo and that supports growth of younger limb buds than traditional systems will allow studies of early Hox gene expression, and contribute to the understanding of very early stages of development. The purpose of the current experiment was to determine if entire limb buds could be cultured in the bioreactor, and to compare the growth and differentiation with that of culturing in a culture dish system. Fore and hind limbs from E11-E13 ICR mouse embryos were cultured for six days, either in the bioreactor or in center-well organ culture dishes, fixed, and embedded for histology. E13 specimens grown in culture dishes were flat, while bioreactor culture specimens had a more in vivo-like 3D limb shape. Sections showed excellent cartilage differentiation in both culture systems, with more cell maturation, and hypertrophy in the specimens cultured in the bioreactor. Younger limb buds fused together during culture, so an additional set of E11.5 limb buds was cultured with and without encapsulation in alginate prior to culturing in the bioreactor. Encapsulated limbs grown in the bioreactor did not fuse together, but developed only the more proximal elements while limbs grown in culture dishes formed proximal and distal elements. Alginate encapsulation may have reduced oxygenation to the progress zone of the developing limb bud resulting in lack of development of the more distal elements. These results show that the bioreactor supports growth and differentiation of skeletal elements in entire E13 limb buds, and that a method to culture younger limb buds without fusing together needs to be developed if any morphometric analysis is to be performed.     

Lipid peroxidation of plants under microgravity and its simulation.

In series of space experiments aboard the biosatellites "Cosmos 1887", "Bion 9", the orbital stations "Salut", "Mir" and under clinostating, changes of lipid peroxidation (LPO) and antioxidation activity (AOA) of Chlorella, Haplopappus tissue culture, wheat and pea roots were determined. The changes had a complex fluctuation character; three steps of response were established: LPO decreasing accompanied by AOA increase; stabilization LPO <==> AOA balance; secondary LPO activation. Most early and highly amplitude decreasing of LPO were fixed in mitochondria. The rate of response have been increased on multicellular level of plants organization.     

Inconsistency of magnetic field and plasma velocity variations in the distant plasma sheet: Violation of the “frozen-in” criterion?

Measurements of the magnetic field and low energy plasma by the GEOTAIL spacecraft have been used to study the relationship between variations of the plasma velocity and of the magnetic field in the distant (100–200 R_E) and middle (40–80 R_E) tail. The analysis was carried out separately for the tail lobes and the plasma sheet. It is shown that the absolute values of the magnetic field and plasma velocity, as well as their corresponding components (V_X and B_X, V_Y and B_Y, V_Z and B_Z), are linearly connected in the tail lobes. In the plasma sheet, however, the plasma velocity and the magnetic field do not seem to be related to one another. The distant plasma sheet seems to be in a regime of turbulence. The diffusion coefficients estimated from our data set of the velocity parameters in the plasma sheet are in good agreement with the theoretical predictions of Antonova and Ovchinnikov (1996, 1999).     

Mars glob: Creation of an international network of Mars surface landers

Program MARS GLOB provides step-by-step deployment of an international network of Mars surface stations by association the MESUR NETWORK (USA), INTERMARS-NET (ESA) programs with the network of small stations and penetrators now under developing in Russia jointly with international cooperation in frameworks of the MARS-96 Project. It is offering also delivery on Mars surface two penetrators and Mars Rover. Now penetrators and Rover are developing by Russia with participation of other countries in frameworks of the MARS-98 (or MARS TOUR) Project.     

Forecasting magnetopause crossing locations by using Neural Networks

Given the highly complex and nonlinear nature of Near Earth Space processes, mathematical modeling of these processes is usually difficult or impossible. In such cases, modeling methods involving Artificial Intelligence may be employed. We demonstrate that data driven models, such as the Neural Network based approach, shows promise in its ability to forecast or predict the behavior of these processes. In this paper, modeling studies for forecasting magnetopause crossing locations are summarized and a Neural Network algorithm is presented to describe the nonlinear time-dependent response of the subsolar region of the magnetopause to varying solar wind conditions. In our approach the past history of the solar wind has, for the first time to the best knowledge of the authors, been included in forecasting the subsolar region of the magnetopause. It is proposed that the data driven approach is a valid approach to understanding and modeling the physical phenomena of Near Earth Space. The only basic requirement for the data driven approach is the availability of representative data for the phenomena. The objective of this paper is to demonstrate that by using WIND and GEOTAIL satellite data a Neural Network based model can be adapted to the modeling of the Earth’s magnetopause.     

Utilization of sweet potatoes in controlled ecological life support systems (CELSS).

A number of studies have selected the sweet potato as a potentially important crop for CELSS. Most hydroponic studies of sweet potatoes have been short term (<80 days). Full term (90 to 150 days) studies of sweet potatoes in hydroponic systems were needed to understand the physiology of storage root enlargement and to evaluate sweet potato production potential for CELSS. Early and late maturing sweet potato varieties were crown in hydroponic systems of different types--static with periodic replacement, flowing with and without recirculation, aggregate, and non-aggregate. In a flowing system with recirculation designed at Tuskegee University using the nutrient film technique (NFT), storage root yields as high as 1790 g were produced with an edible growth rate of up to 66 g m-2 d-1 and a harvest index as high as 89% under greenhouse conditions. Preliminary experiments indicated high yields can be obtained in controlled environmental chambers. Significant cultivar differences were found in all systems studied. Nutritive composition of storage roots and foliage were similar to field-grown plants. The results indicate great potential for sweet potato in CELSS.     

Integrated drought monitoring index: A tool to monitor agricultural drought by using time-series datasets of space-based earth observation satellites

In this study, integrated drought monitoring index (IDMI) was proposed as a tool to assess and monitor the spatio-temporal dynamics of agricultural drought during the northeast monsoon season for the period from 2000 to 2016 in Tamil Nadu state, south-eastern part of Indian peninsula. The IDMI is characterized as the principal component of precipitation condition index (PCI), soil moisture condition index (SMCI), temperature condition index (TCI), and vegetation condition index (VCI) derived from time-series satellite observations of climate hazards group infra-red precipitation with stations (CHIRPS), European space agency climate change initiative (ESA-CCI) and moderate resolution imaging spectroradiometer (MODIS). The study shows that in the year 2016, about 44.4 and 17.8% of Tamil Nadu state was under extreme and severe drought conditions, respectively. Sensitivity analysis of the study shows that PCI is the most influential parameter to IDMI, followed by VCI and TCI. The validation of IDMI with 3-month standardized precipitation index (SPI) by using Pearson correlation test shows a strong positive correlation between IDMI and 3-month SPI with correlation coefficient (r) value of 0.73 and 0.77 for the wet (2005) and dry year (2016), respectively. The study clearly demonstrates the potential of IDMI derived from time-series datasets of earth observation satellites as a tool in assessment and monitoring of spatio-temporal dynamics of agricultural drought. The proposed IDMI could be effectively used as a reliable tool to monitor agricultural drought and develop its mitigation strategies to minimise the adverse effects of drought on agriculture, water resources, and livelihoods of the people.     

The Long-Term Evolution of the Atmosphere of Venus: Processes and Feedback Mechanisms

Space Science Reviews - The BepiColombo Environment Radiation Monitor (BERM) on board the European Space Agency’s Mercury Planetary Orbiter (MPO), is designed to measure the radiation...     

Retrieval of vegetation equivalent water thickness from reflectance using genetic algorithm (GA)-partial least squares (PLS) regression

This study aimed to investigate the performance of genetic algorithms coupled with partial least squares (GA-PLS) modeling of spectral reflectance in retrieving equivalent water thickness (EWT) at leaf and canopy level. A genetic algorithm was used to identify a subset of spectral bands sensitive to the variation in EWT, and PLS was then applied to relate the identified bands to EWT values. GA-PLS was applied to leaf level reflectance available from LOPEX dataset, and canopy data includes reflectance simulated by a leaf radiative transfer model PROSPECT and a canopy radiative transfer model SAILH and acquired by airborne visible/infrared imaging spectrometer (AVIRIS). The results indicate that GA-PLS has the capability of retrieving EWT from leaf and canopy reflectance, and achieved good estimation accuracy, i.e. low root mean square errors (RMSE) and high squared correlation coefficients (R²). For the retrieval at leaf level, the estimation accuracy can be as good as RMSE = 0.0019 g/cm² and R² = 0.939 or better. For the retrieval at canopy level, the model accuracy is RMSE = 0.0061 g/cm² and R² = 0.966 or better when PROSPECT-SAILH simulated reflectance was used; when AVIRIS image spectra were used, the model accuracy is RMSE = 0.0094 g/cm² and R² = 0.8734 for the calibration, and RMSE = 0.0132 g/cm² and R² = 0.7756 for the validation. These results from GA-PLS modeling support the conclusion that GA-PLS has the potential to be applied to AVIRIS, Hyperion and HyMap imagery for retrieving EWT. The selected bands for the AVIRIS datasets differ from those for the LOPEX and PROSPECT-SAILH simulated datasets, and this inconsistence of the selected bands for different datasets indicates that the GA-PLS method has the advantage of tuning the optimum bands for PLS regression and accommodating the effects of confounding factors.     

应用绿色半导体量子点进行乳腺癌原位成像

乳腺癌是癌症中引起妇女死亡的首要因素。本文采用绿色量子点作为荧光显色材料，建立了一种用于早期乳腺癌诊断的原位成像技术。利用生物素标记的抗HER2／neu抗体与乳腺癌细胞表面表达的HER2结合的特点，然后用偶联绿色量子点的链霉亲和素作为荧光检测标记物，与HER2抗原抗体复合物中的生物素发生特异结合，检测出乳腺癌细胞的存在。结果表明，在荧光显微镜下用绿色量子点原位显色的乳腺癌细胞，相对有机染料组显色亮度增强，故检测灵敏度有所提高。