ITASAT-2 Mission Overview

The ITASAT-2 project is part of a progressive development of CubeSat space missions at the Instituto Tecnológico de Aeronáutica (ITA). Focused simultaneously on space weather and on the development of new technological solutions, the ITASAT-2 mission is based on the previous developments of the ITASAT-1 and SPORT missions. Consisting of three 12U CubeSats in a formation flight, the mission expands on the study of ionospheric plasma movements and density, small-scale ionospheric structures, magnetic field, and radiation environment. On the development of technological solutions, the mission proposes to test a baseline option at LEO to understand the influence of ionospheric phenomena and signal deterioration on geolocation/aviation-related services. While it allows for the development of support technologies closely related to airworthiness and flight safety, the formation flight arrangement is expected to provide novel (temporal) insights on the evolution of ionospheric events. This paper presents an overview of the ITASAT-2 mission with the main mission objectives, the concept of operation, initial Systems Engineering analysis, and expected work for the next phases of the project

Engineering Challenges of a CubeSat Mission Around the Moon: First Steps on the Path to SelenITA

Flying beyond Earth\u27s sphere of influence has been part of the main goals in space exploration. Efforts of the Artemis program now encompass different classes of missions, including CubeSats. With the challenges of deep space as mission drivers, planning, designing, launching, and operating a CubeSat for a Moon mission is proving to be a step up in difficulty. In this context, SelenITA Mission is conceived as a science mission supporting the Artemis efforts, planned to operate at Low-Lunar Orbit (LLO), flying below 200 km gathering space weather and geophysics observations, marking the first Brazilian mission to the Moon. This paper outlines the engineering challenges encountered this far in the development of SelenITA. It presents the aspects of lunar orbits and the effects of Moon\u27s potential field on a 12U CubeSat in LLO. A Reference Scenario is established, followed by an exploration of the extreme lunar environment\u27s effect on the satellite\u27s thermal, radiation, and power aspects. Communication limitations in the cislunar environment are analyzed, and strategies for the Attitude and Orbit Control Subsystem are discussed. The paper also addresses the challenges associated with delivery, uncertainties, and supply chain. A conceptual overview of the system is presented, concluding with the future steps

The catalytic subunit of the system L1 amino acid transporter (S<i>lc7a5</i>) facilitates nutrient signalling in mouse skeletal muscle

The System L1-type amino acid transporter mediates transport of large neutral amino acids (LNAA) in many mammalian cell-types. LNAA such as leucine are required for full activation of the mTOR-S6K signalling pathway promoting protein synthesis and cell growth. The SLC7A5 (LAT1) catalytic subunit of high-affinity System L1 functions as a glycoprotein-associated heterodimer with the multifunctional protein SLC3A2 (CD98). We generated a floxed Slc7a5 mouse strain which, when crossed with mice expressing Cre driven by a global promoter, produced Slc7a5 heterozygous knockout (Slc7a5+/-) animals with no overt phenotype, although homozygous global knockout of Slc7a5 was embryonically lethal. Muscle-specific (MCK Cre-mediated) Slc7a5 knockout (MS-Slc7a5-KO) mice were used to study the role of intracellular LNAA delivery by the SLC7A5 transporter for mTOR-S6K pathway activation in skeletal muscle. Activation of muscle mTOR-S6K (Thr389 phosphorylation) in vivo by intraperitoneal leucine injection was blunted in homozygous MS-Slc7a5-KO mice relative to wild-type animals. Dietary intake and growth rate were similar for MS-Slc7a5-KO mice and wild-type littermates fed for 10 weeks (to age 120 days) with diets containing 10%, 20% or 30% of protein. In MS-Slc7a5-KO mice, Leu and Ile concentrations in gastrocnemius muscle were reduced by ∼40% as dietary protein content was reduced from 30 to 10%. These changes were associated with >50% decrease in S6K Thr389 phosphorylation in muscles from MS-Slc7a5-KO mice, indicating reduced mTOR-S6K pathway activation, despite no significant differences in lean tissue mass between groups on the same diet. MS-Slc7a5-KO mice on 30% protein diet exhibited mild insulin resistance (e.g. reduced glucose clearance, larger gonadal adipose depots) relative to control animals. Thus, SLC7A5 modulates LNAA-dependent muscle mTOR-S6K signalling in mice, although it appears non-essential (or is sufficiently compensated by e.g. SLC7A8 (LAT2)) for maintenance of normal muscle mass

Nitric acid and hydrogen peroxide in milk and cheese digestion for the detection of metals

The content of arsenic (As), cadmium (Cd), copper (Cu), chromium (Cr), lead (Pb) and zinc (Zn) in milk and cheeses was determined, comparing the use of nitric acid and a mixture of nitric acid and hydrogen peroxide (HNO3 + H2O2) in acid digestion. The milk was collected from storage tanks in localities of Huejotzingo and cheeses in Santa Ana Xalmimilulco, Huejotzingo, Puebla. Digestion was carried out in a CEM MarsX microwave. The determination was in an ICP OES. As it showed (p &lt;0.01) when using HNO3 (0.13 mg kg-1) with respect to the mixture. The Cd, Zn and Pb showed (p &lt;0.01), with the use of the mixture with respect to HNO3. The content of Cd, As, Cu and Cr in the cheese there was difference (p &lt;0.01) when using HNO3 compared to the mixture. This shows that there is specificity for metal detection, with HNO3 being the most efficientObjective:  To determine the concentration of arsenic (As), cadmium (Cd), copper (Cu), chromium (Cr), lead (Pb), and zinc (Zn) in milk and cheese by comparing the use of nitric acid (HNO3) and a mixture of nitric acid and hydrogen peroxide (HNO3 + H2O2) in acid digestion. Design/methodology/approach: The milk for the study was collected from storage tanks in various localities of Huejotzingo, and the different types of cheese came from Santa Ana Xalmimilulco, Huejotzingo, Puebla, Mexico. Digestion was carried out in a CEM MarsX microwave. Elemental concentrations were determined by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). Results: The combination of HNO3 + H2O2 in milk digestion resulted in higher concentrations of Cd, Pb, and Zn. Conversely, the concentration of As was higher when using only HNO3 for digestion. No significant differences were found for Cr and Cu between the two digestion methods. In the case of Oaxaca cheese, digestion with HNO3 resulted in higher concentrations of As. Acid digestions did not affect the concentrations of the remaining elements. The same behavior was observed for Ranchero cheese, since the digestion combining HNO3 + H2O2 resulted in lower As concentrations, as compared to the digestion with only HNO3. Pb and Zn were not significantly affected by the treatments, while the concentrations of Cd, Cr, and Cu could not be determined when samples were treated with the HNO3 + H2O2 combination. Limitations: In this work we were able to determine the concentration of a number of metals present in milk and cheese using nitric acid and hydrogen peroxide in acid digestion. However, we recommend more tests are carried out to establish which acid or combination of acids allows for a broader detection of metals. Findings/Conclusions: According to the results obtained in this work, we can conclude that there is specificity for metal detection, with HNO3 being the most efficient

Strigolactones Stimulate Arbuscular Mycorrhizal Fungi by Activating Mitochondria

The association of arbuscular mycorrhizal (AM) fungi with plant roots is the oldest and ecologically most important symbiotic relationship between higher plants and microorganisms, yet the mechanism by which these fungi detect the presence of a plant host is poorly understood. Previous studies have shown that roots secrete a branching factor (BF) that strongly stimulates branching of hyphae during germination of the spores of AM fungi. In the BF of Lotus, a strigolactone was found to be the active molecule. Strigolactones are known as germination stimulants of the parasitic plants Striga and Orobanche. In this paper, we show that the BF of a monocotyledonous plant, Sorghum, also contains a strigolactone. Strigolactones strongly and rapidly stimulated cell proliferation of the AM fungus Gigaspora rosea at concentrations as low as 10 (−13) M. This effect was not found with other sesquiterperne lactones known as germination stimulants of parasitic weeds. Within 1 h of treatment, the density of mitochondria in the fungal cells increased, and their shape and movement changed dramatically. Strigolactones stimulated spore germination of two other phylogenetically distant AM fungi, Glomus intraradices and Gl. claroideum. This was also associated with a rapid increase of mitochondrial density and respiration as shown with Gl. intraradices. We conclude that strigolactones are important rhizospheric plant signals involved in stimulating both the pre-symbiotic growth of AM fungi and the germination of parasitic plants

Significance of placental cord insertion site in twin pregnancy

Objective To investigate the association between abnormal cord insertion and the development of twin‐specific complications, including birth‐weight discordance, selective fetal growth restriction (sFGR) and twin‐to‐twin transfusion syndrome (TTTS). Methods This was a single center retrospective cohort study of twin pregnancies. Abnormal cord insertion was defined as either marginal (umbilical cord attachment site less than 2 cm to the nearest margin of the placental disc) or velamentous (cord attached to the membrane before reaching the placental disc with clear evidence of vessels traversing the membranes to connect with the placental disc), as described in placental pathology reports. Twins with major structural or chromosomal abnormalities and monochorionic monoamniotic twins were not included in the study. Information on the pregnancies, ultrasound findings, prenatal investigations and interventions was obtained from the electronic ultrasound database, while data on placental histopathological findings, pregnancy outcome, mode of delivery, birth weight, gestational age at delivery and admission to the neonatal intensive care unit were obtained from maternity records. Categorical variables were compared using the chi‐square or Fisher's exact test, while continuous variables were compared using the Student's t‐test, ANOVA for multiple comparisons and the Kruskal–Wallis test. Results Of the 497 twin pregnancies included in the analysis, 351 (70.6%) were dichorionic and 146 (29.4%) were monochorionic. The incidence of birth‐weight discordance of 25% or more was significantly higher in pregnancies with velamentous and those with marginal cord insertions compared to those with normal cord insertion (24.0%, 15.3% vs 7.6%, P < 0.001 and P = 0.020, respectively). In pregnancies with birth‐weight discordance of 25% or more, the smaller twins had significantly higher prevalence of velamentous (13.8%) and marginal (34.2%) cord insertions compared with the larger twins (1.8% and 18.5%, respectively, P < 0.001). The smaller twins of the monochorionic diamniotic pregnancies showed an even higher prevalence of velamentous (29.5%) and marginal (40.9%) cord insertions compared with the larger twins (2.3% and 31.5%, respectively, P < 0.001). Compared with the normal cord insertion group, only velamentous insertion was associated significantly with the risk of sFGR (odds ratio (OR), 9.24 (95% CI, 2.05–58.84), P < 0.001) and birth‐weight discordance of 20% or more (OR, 4.34 (95% CI, 1.36–14.61), P = 0.007) and 25% or more (OR, 6.81 (95% CI, 1.67–34.12), P = 0.003) in monochorionic twin pregnancies. There was no significant association between velamentous cord insertion and TTTS (P = 0.591), or between marginal cord insertion and the development of sFGR (P = 0.233), birth‐weight discordance of 25% or more (P = 0.114) or TTTS (P = 0.487). Subgroup analysis of dichorionic twins showed that abnormal cord insertion was not associated with the risk of birth‐weight discordance (P = 0.999), sFGR (P = 0.308), composite neonatal adverse outcome (P = 0.637) or intrauterine death (P = 0.349). Conclusion Monochorionic twins with velamentous cord insertion are at increased risk of birth‐weight discordance and sFGR. Sonographic delineation of placental cord insertion could be of value in the antenatal stratification of twin pregnancies. Prospective studies are required to assess the value and predictive accuracy of this potential screening marker

The Effect of Water Immersion during Exercise on Cerebral Blood Flow

Introduction: Regular exercise induces recurrent increases in cerebrovascular perfusion. In peripheral arteries, such episodic increases in perfusion are responsible for improvement in arterial function and health. We examined the hypothesis that exercise during immersion augments cerebral blood flow velocity compared with intensity-matched land-based exercise. Methods: Fifteen normotensive participants were recruited (26 ± 4 yr, 24.3 ± 1.9 kg·m−2). We continuously assessed mean arterial blood pressure, HR, stroke volume, oxygen consumption, and blood flow velocities through the middle and posterior cerebral arteries before, during, and after 20-min bouts of water- and land-based stepping exercise of matched intensity. The order in which the exercise conditions were performed was randomized between subjects. Water-based exercise was performed in 30°C water to the level of the right atrium. Results: The water- and land-based exercise bouts were closely matched for oxygen consumption (13.3 mL·kg−1·min−1 (95% confidence interval (CI), 12.2–14.6) vs 13.5 mL·kg−1·min−1 (95% CI, 12.1–14.8), P = 0.89) and HR (95 bpm (95% CI, 90–101) vs 96 bpm (95% CI, 91–102), P = 0.65). Compared with land-based exercise, water-based exercise induced an increase in middle cerebral artery blood flow velocity (74 cm·s−1 (95% CI, 66–81) vs 67 cm·s−1 (95% CI, 60–74) P < 0.001), posterior cerebral artery blood flow velocity (47 cm·s−1 (95% CI, 40–53) vs 43 cm·s−1 (95% CI, 37–49), P < 0.001), mean arterial blood pressure (106 mm Hg (95% CI, 100–111) vs 101 mm Hg (95% CI, 95–106), P < 0.001), and partial pressure of expired CO2 (P ≤ 0.001). Conclusions: Our findings suggest that water-based exercise augments cerebral blood flow, relative to land-based exercise of similar intensity, in healthy humans

TIP47 functions in the biogenesis of lipid droplets

TIP47 (tail-interacting protein of 47 kD) was characterized as a cargo selection device for mannose 6-phosphate receptors (MPRs), directing their transport from endosomes to the trans-Golgi network. In contrast, our current analysis shows that cytosolic TIP47 is not recruited to organelles of the biosynthetic and endocytic pathways. Knockdown of TIP47 expression had no effect on MPR distribution or trafficking and did not affect lysosomal enzyme sorting. Therefore, our data argue against a function of TIP47 as a sorting device. Instead, TIP47 is recruited to lipid droplets (LDs) by an amino-terminal sequence comprising 11-mer repeats. We show that TIP47 has apolipoprotein-like properties and reorganizes liposomes into small lipid discs. Suppression of TIP47 blocked LD maturation and decreased the incorporation of triacylglycerol into LDs. We conclude that TIP47 functions in the biogenesis of LDs