359,895 research outputs found
Intrauterine repair of gastroschisis in fetal rabbits
Objective: Infants with gastroschisis (GS) still face severe morbidity. Prenatal closure may prevent gastrointestinal organ damage, but intrauterine GS repair (GSR) has not been established yet. Methods: In New Zealand White rabbits we developed and compared GS versus GSR: creation of GS was achieved by hysterotomy, right-sided laparotomy of the fetus and pressure on the abdominal wall to provoke evisceration. GSR was accomplished by careful reposition of eviscerated organs and a running suture of the fetal abdominal wall. For study purposes, 18 animals were divided equally into 3 groups: GS, GS with GSR after 2 h, and unmanipulated controls (C). Vitality was assessed by echocardiography. After 5 h all animals were sacrificed. Results: GSR inflicted no increased mortality, because all fetuses survived GS or GS with GSR. All fetuses with GS demonstrated significant evisceration of abdominal organs. In contrast, the abdominal wall of the fetuses from GSR was intact. Conclusion:The present animal model demonstrated the technical feasibility and success of an intrauterine repair of GS for the first time. However, further long-term studies (leaving GS and GSR in utero for several days) will be necessary to compare survival rates and intestinal injury, motility or absorption. The clinical application of GSR in utero remains a vision so far. Copyright (C) 2003 S. Karger AG, Basel
Leaf-Atmosphere NH3 Exchange in Barley Mutants with Reduced Activities of Glutamine Synthetase
Mutants of barley (Hordeum vulgare L. cv Maris Mink) with 47 or 66% of the glutamine synthetase (GS) activity of the wild type were used for studies of NH3 exchange with the atmosphere. Under normal light and temperature conditions, tissue NH4+ concentrations were higher in the two mutants compared with wild-type plants, and this was accompanied by higher NH3 emission from the leaves. The emission of NH3 increased with increasing leaf temperatures in both wild-type and mutant plants, but the increase was much more pronounced in the mutants. Similar results were found when the light intensity (photosynthetic photon flux density) was increased. Compensation points for NH3 were estimated by exposing intact shoots to 10 nmol NH3 mol-1 air under conditions with increasing temperatures until the plants started to emit NH3. Referenced to 25[deg]C, the compensation points were 5.0 nmol mol-1 for wild-type plants, 8.3 nmol mol-1 for 47% GS mutants, and 11.8 nmol mol-1 for 66% GS mutants. Compensation points for NH3 in single, nonsenescent leaves were estimated on the basis of apoplastic pH and NH4+ concentrations. These values were 0.75, 3.46, and 7.72 nmol mol-1 for wild type, 47% GS mutants, and 66% GS mutants, respectively. The 66% GS mutant always showed higher tissue NH4+ concentrations, NH3 emission rates, and NH3 compensation points compared with the 47% GS mutant, indicating that NH4+ release was curtailed by some kind of compensatory mechanism in plants with only 47% GS activit
Geometrical Scaling in High Energy Hadronic Collisions
After introducing the concept of geometrical scaling (GS) on the example of
deep inelastic ep scattering, we show that GS is also present in the p_T
spectra measured by the LHC. We discuss simple phenomenological signatures of
GS and its applications.Comment: 5 pages, 4 figures, talk presented at the QCD session of Rencontres
de Moriond, 201
Chemical Self Assembly of Graphene Sheets
Chemically derived graphene sheets were found to self-assemble onto patterned
gold structures via electrostatic interactions between noncovalent functional
groups on GS and gold. This afforded regular arrays of single graphene sheets
on large substrates, characterized by scanning electron and Auger microscopy
imaging and Raman spectroscopy. Self assembly was used for the first time to
produce on-substrate and fully-suspended graphene electrical devices. Molecular
coatings on the GS were removed by high current electrical annealing, which
recovered the high electrical conductance and Dirac point of the GS. Molecular
sensors for highly sensitive gas detections are demonstrated with
self-assembled GS devices.Comment: Nano Research, in press, http://www.thenanoresearch.co
Pharmacologic or Genetic Targeting of Glutamine Synthetase Skews Macrophages toward an M1-like Phenotype and Inhibits Tumor Metastasis.
Glutamine-synthetase (GS), the glutamine-synthesizing enzyme from glutamate, controls important events, including the release of inflammatory mediators, mammalian target of rapamycin (mTOR) activation, and autophagy. However, its role in macrophages remains elusive. We report that pharmacologic inhibition of GS skews M2-polarized macrophages toward the M1-like phenotype, characterized by reduced intracellular glutamine and increased succinate with enhanced glucose flux through glycolysis, which could be partly related to HIF1α activation. As a result of these metabolic changes and HIF1α accumulation, GS-inhibited macrophages display an increased capacity to induce T cell recruitment, reduced T cell suppressive potential, and an impaired ability to foster endothelial cell branching or cancer cell motility. Genetic deletion of macrophagic GS in tumor-bearing mice promotes tumor vessel pruning, vascular normalization, accumulation of cytotoxic T cells, and metastasis inhibition. These data identify GS activity as mediator of the proangiogenic, immunosuppressive, and pro-metastatic function of M2-like macrophages and highlight the possibility of targeting this enzyme in the treatment of cancer metastasis
Geometrical scaling in high energy collisions and its breaking
We analyze geometrical scaling (GS) in Deep Inelstic Scattering at HERA and
in pp collisions at the LHC energies and in NA61/SHINE experiment. We argue
that GS is working up to relatively large Bjorken . This allows to
study GS in negative pion multiplicity distributions at NA61/SHINE
energies where clear sign of scaling violations is seen with growing rapidity
when one of the colliding partons has Bjorekn .Comment: 6 pages, 4 figures, presented at the Conference Excited QCD,
Bjelasnica, Sarajevo, Feb. 3 - 9, 201
Combined electrical transport and capacitance spectroscopy of a field effect transistor
We have measured both the current-voltage (-)
and capacitance-voltage (-) characteristics of a
field effect transistor. From the measured capacitance
we calculate the electron surface density and show that its gate voltage
dependence follows the theoretical prediction resulting from the
two-dimensional free electron model. This model allows us to fit the measured
- characteristics over the \emph{entire range} of
. Combining this experimental result with the measured
current-voltage characteristics, we determine the field effect mobility as a
function of gate voltage. We show that for our device this improved combined
approach yields significantly smaller values (more than a factor of 4) of the
electron mobility than the conventional analysis of the current-voltage
characteristics only.Comment: to appear in Applied Physics Letter
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