485 research outputs found
The effect of weathering regime on uranium decay series and osmium in two soil profiles
Two soil profiles from the United States with radically different emplacement and climatic histories were analyzed for U, Th and members of the 238U decay series (234U, 230Th, 226Ra, 210Pb), 137Cs and osmium isotopes. The arid New Mexico profile is developed on an approximately 250,000 years old colluvium while the temperate New Hampshire profile is formed on till after the last glaciation at about 10,000 years ago. Both the profiles show significant 234U/238U, 230Th/234U and 226Ra/230Th disequilibria, however, in the New Hampshire profile, the disequilibria are far more pronounced in mid-depths (20-50 cm). High Os concentration with highly radiogenic 187Os/188Os is another characteristic of the mid-depths of the New Hampshire profile. This layer, particularly at about 30-40 cm depth has the characteristics of a soil developed on black shale, as evidenced from both the high U and Os concentrations and the large excess of 230Th over 238U. This profile clearly shows that the regolith on which the contemporary soil is developing was not homogeneous. The presence of measurable excess 226Ra activity over 230Th activity in both profiles suggests the need for a source of 226Ra external to the regolith in both cases. Atmospheric deposition of 226Ra is a possible source for this 226Ra excess and brings to light the important role of atmospheric deposiion of nuclides and their transport in the soil profile in pedogenic processes. It also shows that regolith developed by glacial processes need not be homogeneous, thereby confounding the understanding of vertically modified soil profiles
A rapid volumetric method for estimation of iron and titanium and its application to ilmenite analysis
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The JAK inhibitor tofacitinib suppresses synovial JAK1-STAT signalling in rheumatoid arthritis.
ObjectiveTofacitinib is an oral Janus kinase (JAK) inhibitor for the treatment of rheumatoid arthritis (RA). The pathways affected by tofacitinib and the effects on gene expression in situ are unknown. Therefore, tofacitinib effects on synovial pathobiology were investigated.MethodsA randomised, double-blind, phase II serial synovial biopsy study (A3921073; NCT00976599) in patients with RA with an inadequate methotrexate response. Patients on background methotrexate received tofacitinib 10 mg twice daily or placebo for 28 days. Synovial biopsies were performed on Days -7 and 28 and analysed by immunoassay or quantitative PCR. Clinical response was determined by disease activity score and European League Against Rheumatism (EULAR) response on Day 28 in A3921073, and at Month 3 in a long-term extension study (A3921024; NCT00413699).ResultsTofacitinib exposure led to EULAR moderate to good responses (11/14 patients), while placebo was ineffective (1/14 patients) on Day 28. Tofacitinib treatment significantly reduced synovial mRNA expression of matrix metalloproteinase (MMP)-1 and MMP-3 (p<0.05) and chemokines CCL2, CXCL10 and CXCL13 (p<0.05). No overall changes were observed in synovial inflammation score or the presence of T cells, B cells or macrophages. Changes in synovial phosphorylation of signal transducer and activator of transcription 1 (STAT1) and STAT3 strongly correlated with 4-month clinical responses (p<0.002). Tofacitinib significantly decreased plasma CXCL10 (p<0.005) at Day 28 compared with placebo.ConclusionsTofacitinib reduces metalloproteinase and interferon-regulated gene expression in rheumatoid synovium, and clinical improvement correlates with reductions in STAT1 and STAT3 phosphorylation. JAK1-mediated interferon and interleukin-6 signalling likely play a key role in the synovial response.Trial registration numberNCT00976599
Classification of Subjects as Slow or Rapid Inactivators of Isoniazid Based on the Ratio of Acetylisoniazid to Isoniazid in Urine Determined by a Simple Colorimetric Method
A method for classifying subjects as slow or rapid inactivators of isoniazid based on the
ratio of acetylisoniazid to isoniazid in a 3-4 hour urine collection following an intramuscular
dose of isoniazid 3 mg./kg. body-weight has been described. Isoniazid and
acetylisoniazid have been estimated using methods requiring the use of only a photoelectric
colorimeter. Of the 279 patients investigated, 169 (61 per cent) were classified
as slow inactivators and 110 (39 per cent) as rapid inactivators. This classification
is an excellent agreement (97 per cent) with that based on a standard spectrophotometric
method
A novel system to obtain addresses of out-patients-assessment in routine clinic practice in Madras
A novel method of obtaining accurate home addresses from out-patients was introduced
as a routine procedure in 6 chest clinics of Madras City, following highly satisfactory results under
study conditions. In this method, the patient is given a card (the Address card), and asked to get
his exact address entered on it by any knowledgeable person of his choice such as the landlord or a
neighbour. An assessment of the system was undertaken after it had been in operation for about
8 months. A complete and legible address was available for 82 % of 3956 patients, the range in the
6 clinics being 74% to 91%. The main causes for failure were: not giving Address card to patient (7 %),
patient not reattending the clinic (6%), and patient reattending but not returning the Address card
(3 %). Corrective measures have now been introduced, and a re-assessment will be undertaken in due
course
A novel system to obtain addresses of out-patients-assessent in routine clinic practice in Madras
A novel method of obtaining accurate home addresses from out-patients was
introduced as a routine procedure in 6 chest clinics of Madras City, following highly
satisfactory results under study conditions. In this method, the patient is given
a card (the address card), and asked to get his exact address entered on it by any
knowledgeable person of his choice such as a landlord or neighbour. An assessment
of the system was undertaken after it had been in operation for about 8 months.
A complete and legible address was available for 82 % of 3956 patients, the range in
the 6 clinics being 74 % to 91 %. The main causes for failure were : not giving address
card to patient (7 %), patient not reattending the clinic (6 %), and patient reattending
but not returning the address card (3%). Corrective measures have now been
introduced, and a re-assessment will be undertaken in due course
<SUP>187</SUP>Re-<SUP>187</SUP>Os in Lesser Himalayan sediments: measurement techniques and preliminary results
The applications of the 187Re-187Os isotope pair as a petrogenetic and geologic tracer are increasing in recent years due to several advances in the chemical extraction and purification of Re and Os, occurring at ppb levels in environmental samples, and in the precise determination of the Os isotope composition. We have established in our laboratory; based on available methods, chemical procedures and Negative Thermal Ionisation Mass Spectrometric techniques for the measurement of Re-Os concentrations in environmental samples and the Os isotope composition in them. Using these techniques, we are able to determine187Os/186Os ratios with a precision of ~1% (±2σμ; twice the standard error of the mean) in several tens of picogram of Os. Preliminary analysis of black shales from the Lower Tal section of the Maldeota phosphorite mine yields a mean187Re-187Os model age of 597 ± 30 Ma. The 187Os/186Os and Os concentration in black shales of the Lesser Himalaya range from 8 to 96 and 0.02 to 13 ng g-1 respectively. The mean 187Os/186Os in these samples is ~ 25, significantly higher than the crustal value of ~ 10.5, suggesting that these black shales could be an important source of radiogenic Os to the rivers draining the Himalaya and to the steady increase in 187Os/186Os of the oceans through the Cenozoic
<SUP>14</SUP>C in air over the Arabian Sea
Global monitoring of radiocarbon in atmospheric CO2 began during the mid fifties to determine the time scales of exchange of radiocarbon (and CO2) between the atmosphere and other terrestrial reservoirs. The distribution of natural radiocarbon in the environment was perturbed significantly during the 1960s through injection of 14C from nuclear weapon tests. This 'bomb 14C has proved to be an excellent tracer to characterize and quantify CO2 exchange between various reservoirs. We have measured radiocarbon activity of marine air over the central and eastern Arabian sea during 1993-95. The mean A 14C values are 121 ±6, 116 ±6 and 105±5%o respectively for these three years. These values, in conjunction with those reported in the literature for troposphere for the decades of 60s through 80s, show that the 14C activity in the tropospheric air has been decreasing exponentially with an e-folding time of -16 years
A note on the breeding of sugarcane varieties resistant to mosaic
The behaviour of certain Coimbatore sugarcane varieties with reference to the mosaic disease has been discussed, showing that those containingSaccharum spontaneum blood are generally resistant or at least tolerant. Preliminary data regarding the supposed correlation between bristles and mosaic resistance have been presented, which indicate that at least in certain cases there appears to be no positive correlation between the high number of bristles and disease resistance, nor in the protection supposed to be afforded by the bristles to the stomata
Uranium isotopes and radium in the Bhagirathi Alaknanda river system - evidence for high uranium mobilization in the Himalaya
Extensive measurements of dissolved 238U and 226Ra concentrations and 234U/238U activity ratio have been made on samples collected from the Bhagirathi, Alaknanda and their tributaries-the source waters of the Ganga. The objectives of this study are to determine (i) the sources of U and Ra to the Ganga river; (ii) the weathering rate of uranium in the Himalaya, and (iii) the role of Himalayan-Tibetan rivers on the marine budget of uranium. The dissolved 238U and 226Ra concentrations in the Ganga source waters are typically ~ 2-μgl-1 and ~ 0.2 dpml-1 respectively. The low 226Ra concentrations relative to 238U in these waters indicate that Ra is far less mobile. The Bhagirathi and Alaknanda weather uranium from their drainage basins at a rate of ~2 kgkm-2yr-1 comparable to that of the other Himalayan rivers like the Yamuna, Gandak and Ghaghara, but orders of magnitude higher than that derived for some of the world's major rivers (Amazon and Congo). These results suggest that large-scale mobilization of uranium in the Himalaya by rivers is ubiquitous. In the global context, the rivers draining the Himalayan-Tibetan region could be a major source of uranium to the oceans and that its supply via these rivers may have considerably influenced the marine budget of uranium
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