The NASA photovoltaic technology program

The NASA Office of Aeronautical and Space Technology OAST Program in space photovoltaics is reviewed. From the perspective of national landmark mission requirements and five year and 25-year long range plans, the texture of the program is revealed. Planar silicon and concentrator GaAs array technology advances are discussed. Advances in lightweight (50 micro cell) arrays and radiation tolerance research are presented. Recent progress in cascade cells and ultralightweight GaAs planar cells is noted. Progress in raising silicon cell voltage to its theoretical maximum is detailed. Advanced concepts such as plasmon converters and the Long Duration Exposure Facility LDEF flight experiments pertaining to solar cell and array technology are also shown

Eigenvector Centrality Distribution for Characterization of Protein Allosteric Pathways

Determining the principal energy pathways for allosteric communication in biomolecules, that occur as a result of thermal motion, remains challenging due to the intrinsic complexity of the systems involved. Graph theory provides an approach for making sense of such complexity, where allosteric proteins can be represented as networks of amino acids. In this work, we establish the eigenvector centrality metric in terms of the mutual information, as a mean of elucidating the allosteric mechanism that regulates the enzymatic activity of proteins. Moreover, we propose a strategy to characterize the range of the physical interactions that underlie the allosteric process. In particular, the well known enzyme, imidazol glycerol phosphate synthase (IGPS), is utilized to test the proposed methodology. The eigenvector centrality measurement successfully describes the allosteric pathways of IGPS, and allows to pinpoint key amino acids in terms of their relevance in the momentum transfer process. The resulting insight can be utilized for refining the control of IGPS activity, widening the scope for its engineering. Furthermore, we propose a new centrality metric quantifying the relevance of the surroundings of each residue. In addition, the proposed technique is validated against experimental solution NMR measurements yielding fully consistent results. Overall, the methodologies proposed in the present work constitute a powerful and cost effective strategy to gain insight on the allosteric mechanism of proteins

Growth performance in heavy lambs experimentally treated with 17 β-estradiol

European and Italian legislation have banned use of growth promoters in livestock since 1988, but epidemiological data show that anabolic drugs are still being used illegally. Recent surveys carried out on the cattle farms in Northern Italy have confirmed the presence of growthpromoting hormones. Authors report data on growth performances in 80 Valle del Belice×Comisana weaned lambs experimentally treated with 17 beta-estradiol with 0.5 ml solution of oil Depot Estradiol ® (containing 5 mg of 17β- estradiol valerate) by intramuscular injection into the thigh. The experiment was founded by the National Ministry of Health, to validate histological test for surveillance and control of growth-promoting hormones in sheep. This study confirmed the strong correlation between clinical and anatomopathological features and growth performances of treated animals. Otherwise, no significant differences were found on in vivo performance of the lambs. Estradiol treatment showed heavier shoulders and necks on treated lambs, while the loins were significantly lighter. Moreover, lambestradiol- treated groups showed lower separable and inseparable fat percentage than lamb-control groups

Bleeding jejunal varices and portal thrombosis in a splenectomized patient with hereditary spherocytosis

Bleeding from varices located in the small bowel is a very uncommon finding; nonetheless, such events accompany with a high mortality rate (1– 4). Moreover, early diagnosis of jejunal or ileal varices cannot usually be accomplished with standard diagnostic tools (ie, esophagogastroduodenoscopy, colonoscopy). Most reports in the literature relate to subjects with liver cirrhosis, often with hepatocarcinoma; in unusual anatomical situations, varices may develop beyond the ligament of Treitz in adjunct to the far more common location in the esophageal and gastric wall. Thrombosis of the portal vein is a common feature in such conditions. Portal thrombosis has also been described in association with overt or latent myeloproliferative diseases (5); its occurrence in nonneoplastic hematological conditions in subjects with normal liver function is quite uncommon. This report describes the observation of jejunal varices, with repeated episodes of “melena of unknown origin,” some of which quite severe, as their clinical presentation in a patient with portal thrombosis and with otherwise absolutely normal liver function, who had undergone splenectomy for hereditary spherocytosis in early adolescence

Human Wharton’s jelly-derived mesenchymal stem cells express several immunomodulatory molecules both in their naïve state and hepatocyte-like differentiated progeny: prospects for their use in liver diseases.

Wharton’s jelly (WJ), the main constituent of umbilical cord, is a reliable source of mesenchymal stem cells (MSC). WJ-MSC show unique ability in crossing lineage borders. As other extraembryonic mesenchymal populations (placenta and amnionderived cells), WJ-MSC express several immunomodulatory molecules, essential during the initial phases of human development. Indeed, our recent work pointed out the expression of non-classical HLA molecules as HLA-G in such cells, together with a favorable combination of B7 costimulators. Very few data in literature suggest that some of the immune features of the naïve cells are maintained after performing differentiation. The aim of this work was extending the knowledge on the expression of immunomodulatory molecules by naïve and differentiated WJ-MSC. To this purpose, WJMSC underwent differentiation to osteoblasts, adipocytes and hepatocyte-like cells. Differentiated cells were characterized, by both RT-PCR, ICC and histological stains for the acquisistion of the desired phenotypical features. RT-PCR and ICC were used to investigate the differential expression of immune-related molecules in control and differentiated cells. WJ-MSC resulted expressing diverse immunomodulatory molecules which spans from non-classical type I HLAs (i.e. HLA-E, -F, -G) , to further members of the B7 family, and of the CEA superfamily, for all of which in vivo immunomodulating functions are known. In addition, we demonstrated for the first time that the expression of these molecules is maintained after performing osteogenic, adipogenic or hepatogenic differentiation. Further experiments are undergoing to better evaluating the implications of these findings in the evolving field of liver regenerative medicine

Evidence for a Novel Reaction Mechanism of a Prompt Shock-Induced Fission Following the Fusion of 78Kr and 40Ca Nuclei at E/A =10 MeV

An analysis of experimental data from the inverse-kinematics ISODEC experiment on 78Kr+40Ca reaction at a bombarding energy of 10 AMeV has revealed signatures of a hitherto unknown reaction mechanism, intermediate between the classical damped binary collisions and fusion-fission, but also substantially different from what is being termed in the literature as fast fission or quasi fission. These signatures point to a scenario where the system fuses transiently while virtually equilibrating mass asymmetry and energy and, yet, keeping part of the energy stored in a collective shock-imparted and, possibly, angular momentum bearing form of excitation. Subsequently the system fissions dynamically along the collision or shock axis with the emerging fragments featuring a broad mass spectrum centered around symmetric fission, relative velocities somewhat higher along the fission axis than in transverse direction, and virtually no intrinsic spin. The class of massasymmetric fission events shows a distinct preference for the more massive fragments to proceed along the beam direction, a characteristic reminiscent of that reported earlier for dynamic fragmentation of projectile-like fragments alone and pointing to the memory of the initial mass and velocity distribution.Comment: 5 PAGES, 6 FIGURE

Monitoring multiple myeloma by idiotype-specific peptide binders of tumor-derived exosomes.

Abstract Tumor-derived exosomes (TDEs) play a pivotal role in tumor establishment and progression, and are emerging biomarkers for tumor diagnosis in personalized medicine. To date, there is a lack of efficient technology platforms for exosome isolation and characterization. Multiple myeloma (MM) is an incurable B-cell malignancy due to the rapid development of drug-resistance. MM-released exosomes express the immunoglobulin B-cell receptor (Ig-BCR) of the tumor B-cells, which can be targeted by Idiotype-binding peptides (Id-peptides). In this study, we analyzed the production of MM-released exosomes in the murine 5T33MM multiple myeloma model as biomarkers of tumor growth. To this end, we selected Id-peptides by screening a phage display library using as bait the Ig-BCR expressed by 5T33MM cells. By FACS, the FITC-conjugated Id-peptides detected the MM-released exosomes in the serum of 5T33MM-engrafted mice, levels of which are correlated with tumor progression at an earlier time point compared to serum paraprotein. These results indicate that Id-peptide-based recognition of MM-released exosomes may represent a very sensitive diagnostic approach for clinical evaluation of disease progression

Association of the degree of adiposity and duration of obesity with measures of cardiac structure and function: The CARDIA study

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109634/1/oby20865.pd

Absence of system xc⁻ on immune cells invading the central nervous system alleviates experimental autoimmune encephalitis

Background: Multiple sclerosis (MS) is an autoimmune demyelinating disease that affects the central nervous system (CNS), leading to neurodegeneration and chronic disability. Accumulating evidence points to a key role for neuroinflammation, oxidative stress, and excitotoxicity in this degenerative process. System x(c)- or the cystine/glutamate antiporter could tie these pathological mechanisms together: its activity is enhanced by reactive oxygen species and inflammatory stimuli, and its enhancement might lead to the release of toxic amounts of glutamate, thereby triggering excitotoxicity and neurodegeneration. Methods: Semi-quantitative Western blotting served to study protein expression of xCT, the specific subunit of system x(c)-, as well as of regulators of xCT transcription, in the normal appearing white matter (NAWM) of MS patients and in the CNS and spleen of mice exposed to experimental autoimmune encephalomyelitis (EAE), an accepted mouse model of MS. We next compared the clinical course of the EAE disease, the extent of demyelination, the infiltration of immune cells and microglial activation in xCT-knockout (xCT(-/-)) mice and irradiated mice reconstituted in xCT(-/-) bone marrow (BM), to their proper wild type (xCT(+/+)) controls. Results: xCT protein expression levels were upregulated in the NAWM of MS patients and in the brain, spinal cord, and spleen of EAE mice. The pathways involved in this upregulation in NAWM of MS patients remain unresolved. Compared to xCT(+/+) mice, xCT(-/-) mice were equally susceptible to EAE, whereas mice transplanted with xCT(-/-) BM, and as such only exhibiting loss of xCT in their immune cells, were less susceptible to EAE. In none of the above-described conditions, demyelination, microglial activation, or infiltration of immune cells were affected. Conclusions: Our findings demonstrate enhancement of xCT protein expression in MS pathology and suggest that system x(c)- on immune cells invading the CNS participates to EAE. Since a total loss of system x(c)- had no net beneficial effects, these results have important implications for targeting system x(c)- for treatment of MS

Kinematical coincidence method in transfer reactions

A new method to extract high resolution angular distributions from kinematical coincidence measurements in binary reactions is presented. Kinematic is used to extract the center of mass angular distribution from the measured energy spectrum of light particles. Results obtained in the case of 10Be+p-->9Be+d reaction measured with the CHIMERA detector are shown. An angular resolution of few degrees in the center of mass is obtained.Comment: 6 Page 10 Figures submitted to Nuclear Instruments and Methods