We present the first L-band spectroscopic observations of a dozen stellar sources in the central 0.5 pc of the GC stellar cluster that are bright in the 2-4 km wavelength domain. The L-band data were ...taken with ISAAC at the VLT UT1 (Antu). With the aid of additional K-band spectroscopic data we derive the optical depth spectra of the sources after fitting their continuum emission with a single reddened blackbody continuum. We also derive intrinsic source spectra by correcting the line of sight extinction via the optical depth spectrum of a late type star that is most likely not affected by local dust emission or extinction at the Galactic Center. The good agreement between the two approaches shows that the overall variation of the line-of-sight extinction across the central 0.5 pc is DAK , 0.5 mag. The extinction-corrected spectra of the hot He-stars resemble pure Rayleigh-Jeans continuum spectra. The intrinsic spectra of all other sources are in agreement with being the result of the continuum emission and absorption features due to the dust in which they are embedded. We interprete both facts as evidence that a significant amount of the absorption takes place within the central parsec of the Galactic Center and is most likely associated with the individual sources there. We find absorption features at 3.0 km, 3.4 km, and 3.48 km wavelength. Correlations between all three features show that they are very likely to arise in the ISM of the central 0.5 pc. Spatially highly variable hydrogen emission lines seen towards the individual sources give evidence of the complex density and temperature structure of the mini-spiral. The featureless K-band spectra of sources like IRS 21 and IRS 1W are consistent with these sources being massive hot stars embedded in the bow shock created by their motion through the dust and gas of the mini-spiral. The bow shock scenario may be applicable to most of the dust-embedded sources in the central stellar cluster. Spectroscopy of high MIR-excess sources 0.5A north of the IRS 13 complex is largely consistent with them being YSOs. However, a bow-shock nature of these sources cannot be excluded. The L-band spectrum at the location of SgrA* closely resembles that of a hot O-type star, such as S2, which was very close to Sgr A* at the time of our observations.
We present the first L-band spectroscopic observations of a dozen stellar sources in the central 0.5 pc of the GC stellar cluster that are bright in the 2-4 μm wavelength domain. The L-band data were ...taken with ISAAC at the VLT UT1 (Antu). With the aid of additional K-band spectroscopic data we derive the optical depth spectra of the sources after fitting their continuum emission with a single reddened blackbody continuum. We also derive intrinsic source spectra by correcting the line of sight extinction via the optical depth spectrum of a late type star that is most likely not affected by local dust emission or extinction at the Galactic Center. The good agreement between the two approaches shows that the overall variation of the line-of-sight extinction across the central 0.5 pc is $\Delta A_{{K}}\leq0.5$ mag. The extinction-corrected spectra of the hot He-stars resemble pure Rayleigh-Jeans continuum spectra. The intrinsic spectra of all other sources are in agreement with being the result of the continuum emission and absorption features due to the dust in which they are embedded. We interprete both facts as evidence that a significant amount of the absorption takes place within the central parsec of the Galactic Center and is most likely associated with the individual sources there. We find absorption features at $3.0~~\mu$m, $3.4~\mu$m, and $3.48~\mu$m wavelength. Correlations between all three features show that they are very likely to arise in the ISM of the central 0.5 pc. Spatially highly variable hydrogen emission lines seen towards the individual sources give evidence of the complex density and temperature structure of the mini-spiral. The featureless K-band spectra of sources like IRS 21 and IRS 1W are consistent with these sources being massive hot stars embedded in the bow shock created by their motion through the dust and gas of the mini-spiral. The bow shock scenario may be applicable to most of the dust-embedded sources in the central stellar cluster. Spectroscopy of high MIR-excess sources 0.5″ north of the IRS 13 complex is largely consistent with them being YSOs. However, a bow-shock nature of these sources cannot be excluded. The L-band spectrum at the location of SgrA* closely resembles that of a hot O-type star, such as S2, which was very close to Sgr A* at the time of our observations.
Science Partners’ Evaluation Group (Evaluation Group) has conducted an independent analysis of the herbicide glufosinate-ammonium (GA) relative to its potential to cause reproductive toxicity in ...humans. Further, the Evaluation Group has evaluated the implementation of Annex 6 of Commission Directive 2001/59/EC (28th ATP of Council Directive 67/548/EEC) and Council Directive 91/414/EEC, with respect to classification of chemicals posing potential reproductive hazards.
After consideration of all information available to us relevant to the potential of glufosinate-ammonium (GA) to cause reproductive toxicity, the Science Partners Evaluation Group concludes that no classification of GA is justified.
The following form the basis of this conclusion.
•
There are no human data to suggest that GA causes reproductive toxicity in women or in their conceptus.
•
The issue concerning possible reproductive hazard to humans is raised solely on the basis of positive animal test results that show GA to cause preimplantation or implantation losses in rats.
Specifically:
a.
Daily treatment with GA had no detectable effect on the earliest stages of the reproductive sequence including gametogenesis, ovulation, mating and conception;
b.
Treatment with GA interfered with rat gestation before and at the stage when the conceptus implants into the uterus. This effect occurred at doses of 360
ppm in the feed (corresponding to daily doses of 27.8
mg/kg
bw) and above; and
c.
After implantation, no further effect of GA on prenatal and post-natal development was recognized. Previous concerns that GA might be toxic to embryonic stages after implantation were not supported by the data. Abortions and stillbirth seen were associated with, and regarded as secondary to, maternal toxicity. There was no evidence suggesting the induction of malformations in the offspring.
•
The mechanism underlying this adverse effect in experimental laboratory animals is identified—inhibition of glutamine synthetase. Glutamine is essential to the viability of the embryo. The embryo is dependent on a maternal source of the amino acid. For embryo lethality to occur, a significant reduction of maternal glutamine is required. Such reduction in maternal glutamine depends on a significant inhibition of glutamine synthetase by GA. This can only occur when the mother is exposed to very high levels of GA.
Specifically:
a.
The reproductive toxicity of GA is confined to very short, early stages of reproduction, during which the conceptus is dependent on maternal glutamine; and
b.
In order for the effect to occur, significant reduction in maternal blood glutamine level is required, which in turn depends on a significant inhibition of glutamine synthetase, induced by high levels of GA in the maternal system.
•
There is no evidence for accumulation of GA in the mammalian organism beyond a factor of two and no evidence for its metabolic toxification.
•
To raise a concern in humans, women would have to be exposed to GA during the very limited time frame of preimplantation or implantation and the exposure would have to be to the exceedingly high levels necessary to alter the maternal metabolism and, correspondingly, result in glutamine levels in maternal tissue and blood plasma being drastically reduced. There is no basis to suggest that such exposures would occur under conditions of normal handling and use.
Specifically:
a.
Under conditions of normal handling and use, operators would never be exposed to GA levels that could potentially inhibit glutamine synthetase to the extent that this inhibition could impair preimplantation or implantation.
b.
All acceptable exposure measurements and predictive calculations confirm this conclusion, and in fact demonstrate that reasonably foreseeable exposure of workers would be to levels significantly below the AOEL.
c.
The evidence is also clear that there is no reproductive toxicity hazard to workers upon reentry tosprayed fields, bystanders, consumers or toddlers.
•
The safety margin compared to the NOAEL in animal studies is sufficiently large to assure protection of the health of workers using GA as well as bystanders, consumers, and toddlers.
•
Pursuant to Annex 6 of Commission Directive 2001/59/EC (28th ATP of Council Directive 67/548/EEC), to justify a classification of category 2 there must be sufficient evidence to produce a strong presumption that human exposure to the substance may result in impaired fertility in humans. It is the conclusion of the Science Partners Evaluation Group that there is no reasonable evidence to suggest a strong presumption of impairment. To the contrary, there is clear evidence demonstrating a strong presumption that exposure to GA would not cause the adverse effect demonstrated in rats.
•
Pursuant to Annex 6 of Commission Directive 2001/59/EC (28th ATP of Council Directive 67/548/EEC), to justify a classification of category 3, there must be sufficient evidence to provide a strong suspicion of impaired fertility in humans. There is no basis to conclude that the animal data demonstrating impaired preimplantation or implantation has any relevance to humans in that the effect found in rats only occurs at levels which would never be experienced by workers under conditions of normal handling and use or by bystanders, consumers, or toddlers.
Members of the Spalt gene family encode putative transcription factors characterized by seven to nine C2H2 zinc finger motifs. Four genes have been identified in mice-Spalt1 to Spalt4 (Sall1 to ...Sall4). Spalt homologues are widely expressed in neural and mesodermal tissues during early embryogenesis. Sall3 is normally expressed in mice from embryonic day 7 (E7) in the neural ectoderm and primitive streak and subsequently in the brain, peripheral nerves, spinal cord, limb buds, palate, heart, and otic vesicles. We have generated a targeted disruption of Sall3 in mice. Homozygous mutant animals die on the first postnatal day and fail to feed. Examination of the oral structures of these animals revealed that abnormalities were present in the palate and epiglottis from E16.5. In E10.5 embryos, deficiencies in cranial nerves that normally innervate oral structures, particularly the glossopharyngeal nerve (IX), were observed. These studies indicate that Sall3 is required for the development of nerves that are derived from the hindbrain and for the formation of adjacent branchial arch derivatives.
Microstructural evolution induced by thermal cycling in a platinum modified diffusion aluminide bond coat was investigated with transmission electron microscopy and elevated temperature X-ray ...diffraction (XRD). Before thermal cycling, the structure of the as-received bond coat was confirmed to be an ordered B2 phase, but significant lattice strains were found which were associated with the formation of a modulated structure. Thermal cycling resulted in significant changes in the microstructure of the bond coat. The compositional development assisted by chemical diffusion during thermal cycling has been related to the transformation of the bond coat from its original B2 structure to a Ni-rich L10 martensite. The L10 martensite was found to be stable at temperatures below approximately 600 °C and the B2 parent phase stable at elevated temperatures. Quantitative XRD measurements indicated that the volume of the B2 phase is approximately 2% larger than that of the martensite, which produces a ∼0.7% linear transformation strain.
The paper presents a technique for computing the individual throughputs and the average queue occupancy when multiple TCP connections share a single bottleneck buffer. The bottleneck buffer is ...assumed to perform congestion feedback via randomized packet marking or drops. We first present a fixed point-based analytical technique to compute the mean congestion window sizes, the mean queue occupancy and the individual throughputs when the TCP flows perform idealized congestion avoidance. We subsequently extend the technique to analyze the case where TCP flows perform generalized congestion avoidance and demonstrate the use of this technique under the Assured Service model, where each flow is assured a minimum traffic rate. Simulations are used to demonstrate the accuracy of this technique for relatively low values of packet dropping probability and a much wider range of packet marking probability.
B-cell lymphomas of mucosa-associated lymphoid tissue (MALT) type develop against a background of chronic inflammation and have functional autoantigen receptors. Because they respond to environmental ...factors
in vivo, the expression of costimulatory molecules, which play a key role in the differentiation of normal B-lymphocytes and in T-/B-cell interaction, may be critical in early MALT-type lymphoma pathogenesis until further chromosomal aberration leads to progression. We found a high number of tumor-infiltrating T-lymphocytes (TITLs) in all low-grade MALT-type lymphomas. The TITLs in low-grade lymphomas were activated and expressed a memory and immunocompetent phenotype. Reverse transcriptase-polymerase chain reaction analyses and immunohistochemistry confirmed the presence of CD40-ligand and Fas-ligand in 80% of low-grade lymphomas. In contrast to the TITLs, the tumor B cells did not express CD40-ligand or Fas-ligand
in vivo or
in vitro. Moreover, the cytokine profile
in vivo suggested a Th2/Th3-weighted profile (interleukin-10, interleukin-13, transforming growth factor β
1. rather than Th1-weighted (interferon-γ, interleukin-2). By interphase fluorescence
in situ hybridization analysis the translocation t(11;18)(q21;q21) was found in four of nine (44%. cases studied. Interestingly, there was a four times higher proliferation and survival rate of purified t(11;18)-positive tumor B cells
in vitro, although there were no significant profile differences from the TITLs
in vivo. The finding of essential costimulating molecules in low-grade MALT-type lymphomas
in vivo indicates a locally directed cognate T-/B-cell interaction. Consequently, a potentially equipped inflammatory background may not only determine the fate of autoreactive B-cells, but is also crucial to lymphoma maintenance and progression.
Gap junction channels in the rodent liver are composed of connexin26 (Cx26) and connexin32 (Cx32) proteins. Gap junctional intercellular communication in the mouse liver enhances the effects of ...hormonal or sympathetic stimulation of glucose release from glycogen stores. To determine whether contraction of bile canaliculi and bile secretion are dependent on the function of gap junction channels, we compared wild-type and connexin32-deficient mice. Confocal laser scanning microscopy of the wild-type mouse liver confirmed the close association of connexin26 and -32 proteins with the zona occludens-1 protein and actin filaments of the bile canaliculi. The decrease of bile flow after electrical stimulation of sympathetic nerves in the perfused liver was attenuated in the Cx32-deficient liver compared with wild-type controls. The amount of secreted bile, however, was similar in wild-type and Cx32-deficient livers. Furthermore, Cx32-deficient mice exhibited dilated bile canaliculi, suggesting that the contraction of bile canaliculi could be impaired in these animals.
Ovine trophoblast protein-1 (oTP-1) is a unique, Type I, trophoblast interferon (IFN) that possesses potent antiviral activity and is thought to be primarily responsible for maternal recognition of ...pregnancy in sheep. To provide sufficient amounts of protein for detailed studies, a synthetic gene for oTP-1 was designed and assembled in Escherichia coli, subcloned into a yeast expression plasmid, and used to overproduce recombinant oTP-1 in Saccharomyces cerevisiae. Recombinant oTP-1 was purified from soluble yeast extract using sequential ion-exchange and molecular sieve chromatography. Recombinant oTP-1 purified in this fashion exhibited potent antiviral activity (0.6 x 10(8) U/mg) similar to native oTP-1. This expression system will enable production of large quantities of soluble, biologically active, and correctly processed recombinant oTP-1. Furthermore, the synthetic gene construct facilitates introduction of mutations for ongoing structure/function studies of this unique, Type I, trophoblast IFN.
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