89 research outputs found
Lymph node homing cells biologically enriched for γδ T cells express multiple genes from the T19 repertoire
Sheep γδ T cells have been shown serologically to express T19, a membrane protein of 180-200 kDa which is a member of the scavenger receptor superfamily. Previous work from this laboratory resulted in the detection of a multigene family of T19-like genes in the sheep genome. In this study nucleotide sequences from several T19 genes were determined and are reported along with the corresponding segments of a number of expressed mRNA molecules. A segment of a single sheep T19-like gene was sequenced and these data, along with the corresponding sequences from cloned T19-like cDNA molecules from sheep and cow, were used to design an ollgonucleotide primer system suitable for amplification of corresponding segments of many T19 genes and their cDNAs. Between 30 and 40% of cloned T19 genes were amenable to amplification using the selected primers, and sequence analysis of cloned PCR products confirmed that different T19 genes encode unique amino acid sequences. The expression of multiple T19 genes was established using cDNA molecules obtained from a single sample of sheep lymphocyte mRNA. The possible role of the T19 family of genes is discusse
Retractable carbon fibre targets for measuring beam profiles at the SLC collision point
Retractable targets of carbon fibres with nominal diameters of 30, 7 and 4.5 [mu]m have been in use at the collision point of the SLC (the SLAC Linear Collider). The target mechanism is compatible with the Mark II detector now in place at the collision point. Beam profiles are measured in horizontal and vertical axes by using magnetic dipoles to scan the beams across the fibres. Two signal detection mechanisms are available. Electron emission from the fibres is measured with the help of charge-sensitive amplifiers. Bremsstrahlung from the fibres is detected by downstream counters. Examples of measurements are given, and limits on the use of the techniques are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27886/1/0000300.pd
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Cr(VI) Effect on Tc-99 Removal from Hanford Low-Activity Waste Simulant by Ferrous Hydroxide.
Here, Cr(VI) effects on Tc-immobilization by Fe(OH)2(s) are investigated while assessing Fe(OH)2(s) as a potential treatment method for Hanford low-activity waste destined for vitrification. Batch studies using simulated low-activity waste indicate that Tc(VII) and Cr(VI) removal is contingent on reduction to Tc(IV) and Cr(III). Furthermore, complete removal of both Cr and Tc depends on the amount of Fe(OH)2(s) present, where complete Cr and Tc removal requires more Fe(OH)2(s) (∼200 g/L of simulant), than removing Cr alone (∼50 g/L of simulant). XRD analysis suggests that Fe(OH)2(s) reaction and transformation in the simulant produces mostly goethite (α-FeOOH), where Fe(OH)2(s) transformation to goethite rather than magnetite is likely due to the simulant chemistry, which includes high levels of nitrite and other constituents. Once reduced, a fraction of Cr(III) and Tc(IV) substitute for octahedral Fe(III) within the goethite crystal lattice as supported by XPS, XANES, and/or EXAFS results. The remaining Cr(III) forms oxide and/or hydroxide phases, whereas Tc(IV) not fully incorporated into goethite persists as either adsorbed or partially incorporated Tc(IV)-oxide species. As such, to fully incorporate Tc(IV) into the goethite crystal structure, additional Fe(OH)2(s) (>200 g/L of simulant) may be required
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Reduction and Simultaneous Removal of 99Tc and Cr by Fe(OH)2(s) Mineral Transformation.
Technetium (Tc) remains a priority remediation concern due to persistent challenges, including mobilization due to rapid reoxidation of immobilized Tc, and competing comingled contaminants, e.g., Cr(VI), that inhibit Tc(VII) reduction and incorporation into stable mineral phases. Here Fe(OH)2(s) is investigated as a comprehensive solution for overcoming these challenges, by serving as both the reductant, (Fe(II)), and the immobilization agent to form Tc-incorporated magnetite (Fe3O4). Trace metal analysis suggests removal of Tc(VII) and Cr(VI) from solution occurs simultaneously; however, complete removal and reduction of Cr(VI) is achieved earlier than the removal/reduction of comingled Tc(VII). Bulk oxidation state analysis of the final magnetite solid phase by XANES shows that the majority of Tc is Tc(IV), which is corroborated by XPS measurements. Furthermore, EXAFS results show successful, albeit partial, Tc(IV) incorporation into magnetite octahedral sites. Cr XPS analysis indicates reduction to Cr(III) and the formation of a Cr-incorporated spinel, Cr2O3, and Cr(OH)3 phases. Spinel (modeled as Fe3O4), goethite (α-FeOOH), and feroxyhyte (δ-FeOOH) are detected in all reacted final solid phase samples analyzed by XRD. Incorporation of Tc(IV) has little effect on the spinel lattice structure. Reaction of Fe(OH)2(s) in the presence of Cr(III) results in the formation of a spinel phase that is a solid solution between magnetite (Fe3O4) and chromite (FeCr2O4)
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Getters for improved technetium containment in cementitious waste forms.
A cementitious waste form, Cast Stone, is a possible candidate technology for the immobilization of low activity nuclear waste (LAW) at the Hanford site. This work focuses on the addition of getter materials to Cast Stone that can sequester Tc from the LAW, and in turn, lower Tc release from the Cast Stone. Two getters which produce different products upon sequestering Tc from LAW were tested: Sn(II) apatite (Sn-A) that removes Tc as a Tc(IV)-oxide and potassium metal sulfide (KMS-2) that removes Tc as a Tc(IV)-sulfide species, allowing for a comparison of stability of the form of Tc upon entering the waste form. The Cast Stone with KMS-2 getter had the best performance with addition equivalent to ∼0.08wt% of the total waste form mass. The observed diffusion (Dobs) of Tc decreased from 4.6±0.2×10-12cm2/s for Cast Stone that did not contain a getter to 5.4±0.4×10-13cm2/s for KMS-2 containing Cast Stone. It was found that Tc-sulfide species are more stable against re-oxidation within getter containing Cast Stone compared with Tc-oxide and is the origin of the decrease in Tc Dobs when using the KMS-2
Neutrophil Interactions with Keratocytes during Corneal Epithelial Wound Healing: A Role for CD18 Integrins
PURPOSE. To determine the role of keratocytes and leukocyte  2 (CD18) integrins in neutrophil (PMN) migration through the corneal stroma after epithelial scrape injury. METHODS. Using C57BL/6 wild-type and CD18 Ϫ/Ϫ mice, corneas were excised at 6 hours (wild-type) or 24 hours (CD18 Ϫ/Ϫ ) after central corneal epithelial abrasion, time points determined previously to have similar levels of emigrated PMNs. Corneas were prepared for ultrastructural morphometric analysis of PMNs, keratocyte networks, and collagen. RESULTS. Transmission electron microscopy revealed intact keratocyte networks within the paralimbus that were morphometrically similar, regardless of epithelial injury or mouse genotype. Secondary to epithelial abrasion, extravasated PMNs within the paralimbus developed close contacts with keratocytes and collagen. In wild-type mice, 40% of the PMN surface was in contact with the keratocyte surface, and this value decreased to 10% in CD18 Ϫ/Ϫ mice. PMN contact with collagen was similar in wild-type and CD18 Ϫ/Ϫ mice, with approximately 50% of the PMN surface contacting the collagen fibrils. Since corneal edema resulting from scrape injury was similar, regardless of genotype and did not involve structural changes in collagen fibrils, these data favor a direct role for CD18 in mediating PMN contact with keratocytes. CONCLUSIONS. The data show that in response to epithelial scrape injury, PMN migration in the corneal stroma involves close contact between keratocytes and collagen. Although PMN-keratocyte contacts require CD18 integrins, contact with collagen is CD18 independent. Fundamentally, PMN migration along keratocyte networks constitutes the beginning of a new experimental concept for understanding leukocyte migration within the wounded cornea. (Invest Ophthalmol Vis Sci. 2007; 48:5023-5029
Weak Lensing of the CMB: Sampling Errors on B-Modes
The B modes generated by the lensing of CMB polarization are a primary target
for the upcoming generation of experiments and can potentially constrain
quantities such as the neutrino mass and dark energy equation of state. The net
sample variance on the small scale B modes out to l=2000 exceeds Gaussian
expectations by a factor of 10 reflecting the variance of the larger scale
lenses that generate them. It manifests itself as highly correlated band powers
with correlation coefficients approaching 70% for wide bands of Delta l/l
\~0.25. It will double the total variance for experiments that achieve a
sensitivity of approximately 4 uK-arcmin and a beam of several arcminutes or
better. This non-Gaussianity must be taken into account in the analysis of
experiments that go beyond first detection.Comment: 6 pages, 4 figures, submitted to PRD; small problem with detector
noise calc fixed (5uK'->4uK') main conclusions unchange
Adjunctive long-acting risperidone in patients with bipolar disorder who relapse frequently and have active mood symptoms
<p>Abstract</p> <p>Background</p> <p>The objective of this exploratory analysis was to characterize efficacy and onset of action of a 3-month treatment period with risperidone long-acting injection (RLAI), adjunctive to an individual's treatment regimen, in subjects with symptomatic bipolar disorder who relapsed frequently and had significant symptoms of mania and/or depression.</p> <p>Methods</p> <p>Subjects with bipolar disorder with ≥4 mood episodes in the past 12 months entered the open-label stabilization phase preceding a placebo-controlled, double-blind study. Subjects with significant depressive or manic/mixed symptoms at baseline were analyzed. Significant depressive symptoms were defined as Montgomery-Åsberg Depression Rating Scale (MADRS) ≥16 and Young Mania Rating Scale (YMRS) < 16; manic/mixed symptoms were YMRS ≥16 with any MADRS score. Subjects received open-label RLAI (25-50 mg every 2 weeks) for 16 weeks, adjunctive to a subject's individualized treatment for bipolar disorder (mood stabilizers, antidepressants, and/or anxiolytics). Clinical status was evaluated with the Clinical Global Impressions of Bipolar Disorder-Severity (CGI-BP-S) scale and changes on the MADRS and YMRS scales. Within-group changes were evaluated using paired <it>t </it>tests; categorical differences were assessed using Fisher exact test. No adjustment was made for multiplicity.</p> <p>Results</p> <p>162 subjects who relapsed frequently met criteria for significant mood symptoms at open-label baseline; 59/162 (36.4%) had depressive symptoms, 103/162 (63.6%) had manic/mixed symptoms. Most subjects (89.5%) were receiving ≥1 medication for bipolar disorder before enrollment. Significant improvements were observed for the total population on the CGI-BP-S, MADRS, and YMRS scales (p < .001 vs. baseline, all variables). Eighty-two (53.3%) subjects achieved remission at the week 16 LOCF end point. The subpopulation with depressive symptoms at open-label baseline experienced significant improvement on the CGI-BP-S and MADRS scales (p < .001 vs. baseline, all variables). Subjects with manic/mixed symptoms at baseline had significant improvements on the CGI-BP-S and YMRS scales (p < .001 vs. baseline, all variables). No unexpected tolerability findings were observed.</p> <p>Conclusions</p> <p>Exploratory analysis of changes in overall clinical status and depression/mania symptoms in subjects with symptomatic bipolar disorder who relapse frequently showed improvements in each of these areas after treatment with RLAI, adjunctive to a subject's individualized treatment. Prospective controlled studies are needed to confirm these findings.</p
Androgen receptor footprint on the way to prostate cancer progression
The prostate gland is exquisitely sensitive to androgen receptor (AR) signaling. AR signaling is obligatory for prostate development and changes in AR levels, its ligands or shifts in AR mode of action are reflected in the physiology of the prostate. The AR is intimately linked to prostate cancer biology through the regulation of epithelial proliferation, suppression of apoptosis and the development of castration-resistant disease. Thus, AR is the primary therapeutic target in various prostate diseases such as BPH and cancer. Although some tumors lose AR expression, most retain the AR and have elevated levels and/or shifts in activity that are required for tumor progression and metastasis. New AR inhibitors currently in clinical trials with higher receptor affinity and specificity may improve prostate cancer patient outcome. Several events play an important role in initiation, primary tumor development and metastatic spread. Androgen receptor activity and promoter specificity change due to altered coregulator expression. Changes in epigenetic surveillance alter the AR cistrome. Both systemic and local inflammation increases with PCa progression affecting AR levels, activity, and requirement for ligand. Our current understanding of AR biology suggest that global androgen suppression may drive the development of castration-resistant disease and therefore the question remains: Does effective inhibition of AR activity mark the end of the road for PCa or only a sharp turn toward a different type of malignancy
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