Overview of the Mars Pathfinder mission and assessment of landing site predictions

Chemical analyses returned by Mars Pathfinder indicate that some rocks may be high in silica, implying differentiated parent materials. Rounded pebbles and cobbles and a possible conglomerate suggest fluvial processes that imply liquid water in equilibrium with the atmosphere and thus a warmer and wetter past. The moment of inertia indicates a central metallic core of 1300 to 2000 kilometers in radius. Composite airborne dust particles appear magnetized by freeze-dried maghemite stain or cement that may have been leached from crustal materials by an active hydrologic cycle. Remote-sensing data at a scale of generally greater than approximately 1 kilometer and an Earth analog correctly predicted a rocky plain safe for landing and roving with a variety of rocks deposited by catastrophic floods that are relatively dust-free.     

Comparison of helium dilution and plethysmographic lung volumes in pregnant women

The multibreath helium equilibration method is the technique recommended for routine measurement of static lung volumes in normal subjects. However, pregnancy could be an exception to this general rule, due to airway closure during the second half of gestation. The aim of this study was to compare the measurements of lung volumes by plethysmography and helium dilution during pregnancy. Twenty three healthy women were studied at 12, 24 and 36 weeks of pregnancy, and 4 months postpartum. Total lung capacity (TLC), functional residual capacity (FRC) and residual volume (RV) were measured by multibreath helium equilibration (TLCHe, FRCHe and RVHe) and by plethysmography (TLCbox, FRCbox and RVbox). Only at 36 weeks were there differences between the two methods. RVbox was significantly larger than RVHe (1.01+/-0.18 vs 0.77+/-0.21 L; p<0.001). FRCbox was larger than FRCHe (1.95+/-0.32 vs 1.60+/-0.32 L; p<0.001) and TLCbox was larger than TLCHe (4.83+/-0.52 vs 4.45+/-0.51 L; p<0.05). The 95% limits of agreement for differences between lung volumes measured by the two techniques (helium dilution - plethysmography) at 36 weeks were: -0.42 to -0.06 L for RV; -0.54 to -0.17 L for FRC; and -0.66 to -0.11 L for TLC. We conclude that using the multibreath helium equilibration method to measure lung volumes in at-term pregnant women results in underestimation of functional residual capacity and total lung capacity.     

cAMP and Ca2+ involvement in the mitochondrial response of cultured fetal rat hepatocytes to adrenaline

The effect of adrenaline on the control of respiratory activity of mitochondria from fetal hepatocytes in primary culture was studied. In the absence of adrenaline, the respiratory control ratio (RCR) of mitochondria increased during the first 3 days of culture due to a decrease in the rate of state 4 respiration. The presence of adrenaline in the incubation medium further increased the mitochondrial RCR through a decrease in the rate of respiration in state 4 and to an increase in the respiration rate in state 3. The effect of adrenaline was mimicked by dibutyryl-cAMP, forskolin, and isobutyl methyl xanthine. All these compounds increased cAMP concentrations, suggesting that cAMP may be involved in the effect of adrenaline. The increase in intracellular free Ca2+ concentrations caused by phenylephrine, vasopressin, or thapsigargin was also accompanied by an increase in the RCR, suggesting that both phenomena are associated. Dibutyryl-cAMP also increased free Ca2+ concentrations, suggesting that the effects of cAMP may be mediated by free Ca2+ concentrations. Adrenaline, dibutyryl-cAMP, phenylephrine, vasopressin, and thapsigargin promoted adenine nucleotide accumulation in mitochondria; this may be an intermediate step in the activation of mitochondrial respiratory function. These results suggest that the stimulatory effect of adrenaline on mitochondrial maturation in cultured fetal rat hepatocytes may be exerted through a mechanism in which both cAMP and Ca2+ act as second messengers. It is concluded that the effect of adrenaline on mitochondrial maturation is exerted by both alpha- and beta-adrenergic mechanisms and is mediated by the increase in adenine nucleotide contents of mitochondria.     

Effect of a three month training period on the maximal oxygen deficiency in high level performance sprinters

We investigated in vivo expression of myosin heavy chain (MHC) isoforms, 17 kDa myosin light chain (MLC17), and phosphorylation of the 20 kDa MLC (MLC20) as well as mechanical performance of chemically skinned fibers of normal and hypertrophied smooth muscle (SM) of human myometrium. According to their immunological reactivity, we identified three MHC isoenzymes in the human myometrium: two SM-MHC (SM1 with 204 kDa and SM2 with 200 kDa), and one non-muscle specific MHC (NM with 196 kDa). No cross-reactivity was detected with an antibody raised against a peptide corresponding to a seven amino acid insert at the 25K/50K junction of the myosin head (a-25K/50K) in both normal and hypertrophied myometrium. In contrast, SM-MHC of human myomatous tissue strongly reacted with a-25K/50K. Expression of SM1/SM2/NM (%) in normal myometrium was 31.7/34.7/33.6 and 35.1/40.9/24 in hypertrophied myometrium. The increased SM2 and decreased NM expression in the hypertrophied state was statistically significant (P < 0.05). MHC isoform distribution in myomatous tissue was similar to normal myometrium (36.3/35.3/29.4). In vivo expression of MLC17a increased from 25.5% in normal to 44.2% in hypertrophied (P < 0.001) myometrium. Phosphorylation levels of MLC20 upon maximal Ca(2+)-calmodulin activation of skinned myometrial fibers were the same in normal and hypertrophied myometrial fibers. Maximal force of isometric contraction of skinned fibers (pCa 4.5, slack-length) was 2.85 mN/mm2 and 5.6 mN/mm2 in the normal and hypertrophied state, respectively (P < 0.001). Apparent maximal shortening velocity (Vmax(appt), extrapolated from the force-velocity relation) of myometrium rose from 0.13 muscle length s-1 (ML/s) in normal to 0.24 ML/s in hypertrophied fibers (P < 0.001).     

Effect of Simulated Microgravity on the Activity of Regulatory Enzymes of Glycolysis and Gluconeogenesis in Mice Liver

Gravity supports all the life activities present on earth. Microgravity environments have effect on the biological functions and physiological status of an individual. The present study was undertaken to investigate the effect of simulated microgravity on important regulatory enzymes of carbohydrate metabolism in liver using HLS mice model. Following hind limb unloading of mice for 11 days the animal’s average body weights were found to be not different, while the liver weights were decreased and found to be significantly different (p < 0.05) from control mice. Further, in liver the specific activity of hexokinase enzyme was reduced (p < 0.02) and the phosphoenolpyruvate carboxykinase activity was significantly increased in simulated microgravity subjected mice compared to control (p < 0.003). Immunoblot analysis show decreased phosphofructokinase-2 activity in HLS mice compared to control. Liver lactate dehydrogenase activity significantly reduced in simulated microgravity subjected mice (p < 0.005). Thus in our study the rodents have adapted to simulated microgravity conditions, with decreased glycolysis and increased gluconeogenesis in liver and reciprocally regulated.     

Radiolabeled Polymeric Nanoconstructs Loaded with Docetaxel and Curcumin for Cancer Combinatorial Therapy and Nuclear Imaging

Growing evidence suggests that multifaceted diseases as cancer can be effectively tackled by hitting simultaneously different biological targets and monitoring patient‐specific responses. Combinatorial therapies, relying on the administration of two or more molecules with different cytotoxic mechanisms, are rapidly progressing in the clinic. Here, 100 nm spherical polymeric nanoconstructs (SPNs) are proposed for the combinatorial treatment of tumors by codelivering a potent antimitotic drug—docetaxel (DTXL)—and a broad spectrum anti‐inflammatory molecule—curcumin (CURC). In vitro, SPNs loaded with DTXL and CURC induce a threefold decrease in IC₅₀ as compared to DTXL‐loaded SPNs. This synergic antitumor effect is also significant in mouse models of glioblastoma multiforme, where, after 22 d of treatment, the combinatorial approach leads to complete disease regression. At 90 d post‐treatment initiation, mice injected with DTXL + CURC SPNs have a 100% survival, whereas only 50% of the DTXL SPN treated mice survive. SPNs are also labeled with radioactive ⁶⁴Cu(DOTA) molecules to document, via PET imaging, the progressive tumor mass shrinkage. Sensitization of DTXL by CURC is associated with NF‐κB downregulation and increased apoptosis. These theranostic nanoconstructs could be used for combinatorial treatment and assessment of therapeutic efficacy in other malignancies.     

Effects of the model selected for the power curve on the site effectiveness and the capacity factor of a pitch regulated wind turbine

The present work is based on the fact that site effectiveness is a relevant value when analysing the suitability of a location for constant-speed wind turbines. An analytical expression is developed to calculate the said effectiveness by means of a potential adjustment model to the ascending segment of the power curve in pitch regulated wind turbines. Upon analysis of the results obtained for maximum effectiveness in a given location, using both the potential model and the quadratic model applied in earlier studies, no significant differences were observed in wind conditions of interest for wind energy applications. Notwithstanding, when the cut-in wind speed was compared, corresponding to the maximum effectiveness values at the same location according to the two models indicated, noticeable differences were observed. It can therefore be deduced that, when selecting this design parameter, a careful study should be made in order to determine which model best fits the power curve of the wind turbine under analysis for a specific location.