313 research outputs found
Temperature-sensitive adult plant leaf rust resistance in bread wheat (triticum aestivum L.)
Temperature sensitivity of the adult plant resistance shown by 16 bread wheat lines against race 77-5 of
Puccinia recondita (the most common and virulent) on the Indian sub-continent was studied. The infection types on
these 16 lines were also compared with those of the known adult plant resistance genes Lr12, Lr13, Lr22a, Lr22b,
Lr34 and Lr37. Frontana, CIM25 (a leaf-rust resistant breeding line), Pavon 76, Pari 73 and Flinders carried lowtemperature
adult plant resistance (LTAP) which was expressed only at 14.5°C. The adult plant resistance of Chris,
Arz, Mukta, WW15(R) and VL421 was best expressed at 30°C, and these 5 wheats carried high temperature adult
plant resistance (HTAP). The adult plant resistance of WH291 was expressed equally at 14.5, 20 and 30°C. The
infection pattern of Mentana, WL410, IWP72, HD2204 and Son-Kl-Rend was similar to that of Thatcher near-isogenic
lines carrying the genes Lr22a and Lr37 and their adult plant resistance was expressed only at 20°C. The Thatcher
near-isogenic lines carrying the genes Lr12, Lr13, Lr22b and Lr34, and WL711 having the gene Lr13 did not show
resistance against race 77-5
Development Of Ion Chromatography Methods To Support Testing Of The Glycolic Acid Reductant Flowsheet In The Defense Waste Processing Facility
Ion Chromatography (IC) is the principal analytical method used to support studies of Sludge Reciept and Adjustment Tank (SRAT) chemistry at DWPF. A series of prior analytical ''Round Robin'' (RR) studies included both supernate and sludge samples from SRAT simulant, previously reported as memos, are tabulated in this report.2,3 From these studies it was determined to standardize IC column size to 4 mm diameter, eliminating the capillary column from use. As a follow on test, the DWPF laboratory, the PSAL laboratory, and the AD laboratory participated in the current analytical RR to determine a suite of anions in SRAT simulant by IC, results also are tabulated in this report. The particular goal was to confirm the laboratories ability to measure and quantitate glycolate ion. The target was + or - 20% inter-lab agreement of the analyte averages for the RR. Each of the three laboratories analyzed a batch of 12 samples. For each laboratory, the percent relative standard deviation (%RSD) of the averages on nitrate, glycolate, and oxalate, was 10% or less. The three laboratories all met the goal of 20% relative agreement for nitrate and glycolate. For oxalate, the PSAL laboratory reported an average value that was 20% higher than the average values reported by the DWPF laboratory and the AD laboratory. Because of this wider window of agreement, it was concluded to continue the practice of an additional acid digestion for total oxalate measurement. It should also be noted that large amounts of glycolate in the SRAT samples will have an impact on detection limits of near eluting peaks, namely Fluoride and Formate. A suite of scoping experiments are presented in the report to identify and isolate other potential interlaboratory disceprancies. Specific ion chromatography inter-laboratory method conditions and differences are tabulated. Most differences were minor but there are some temperature control equipment differences that are significant leading to a recommendation of a heated jacket for analytical columns that are remoted for use in radiohoods. A suggested method improvement would be to implement column temperture control at a temperature slightly above ambient to avoid peak shifting due to temperature fluctuations. Temperature control in this manner would improve short and longer term peak retention time stability. An unknown peak was observed during the analysis of glycolic acid and SRAT simulant. The unknown peak was determined to best match diglycolic acid. The development of a method for acetate is summaraized, and no significant amount of acetate was observed in the SRAT products tested. In addition, an alternative Gas Chromatograph (GC) method for glycolate is summarized
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WASHING AND DEMONSTRATION OF THE DWPF FLOWSHEET IN THE SRNL SHIELDED CELLS USING POST ALUMINUM DISSOLUTION TANK 51 SLUDGE SLURRY
The remaining contents of Tank 51 from Sludge Batch 4 will be blended with Purex sludge from Tank 7 to constitute Sludge Batch 5 (SB5). The Savannah River Site (SRS) Liquid Waste Organization (LWO) has completed caustic addition to Tank 51 to perform low temperature Al dissolution on the H-Modified (HM) sludge material to reduce the total mass of sludge solids and Al being fed to the Defense Waste Processing Facility (DWPF). The Savannah River National Lab (SRNL) has also completed aluminum dissolution tests using a 3-L sample of Tank 51 sludge slurry through funding by DOE EM-21. This report documents assessment of downstream impacts of the aluminum dissolved sludge, which were investigated so technical issues could be identified before the start of SB5 processing. This assessment included washing the aluminum dissolved sludge to a Tank Farm projected sodium concentration and weight percent insoluble solids content and DWPF Chemical Process Cell (CPC) processing using the washed sludge. Based on the limited testing, the impact of aluminum dissolution on sludge settling is not clear. Settling was not predictable for the 3-L sample. Compared to the post aluminum dissolution sample, settling after the first wash was slower, but settling after the second wash was faster. For example, post aluminum dissolution sludge took six days to settle to 60% of the original sludge slurry height, while Wash 1 took nearly eight days, and Wash 2 only took two days. Aluminum dissolution did impact sludge rheology. A comparison between the as-received, post aluminum dissolution and washed samples indicate that the downstream materials were more viscous and the concentration of insoluble solids less than that of the starting material. This increase in viscosity may impact Tank 51 transfers to Tank 40. The impact of aluminum dissolution on DWPF CPC processing cannot be determined because acid addition for the Sludge Receipt and Adjustment Tank (SRAT) cycle was under-calculated and thus under-added. Although the sludge was rheologically thick throughout the SRAT and Slurry Mix Evaporator (SME) cycles, this may have been due to the under addition of acid. Aluminum dissolution did, however, impact analyses of the SRAT receipt material. Two methods for determining total base yielded significantly different results. The high hydroxide content and the relatively high soluble aluminum content of the washed post aluminum dissolution sludge likely contributed to this difference and the ultimate under addition of acid. It should be noted that the simulant used to provide input for the SRAT cycle was an inadequate representation of the waste in terms of acid demand, likely due to the differences in the form of aluminum and hydroxide in the simulant and actual waste. Based on the results of this task, it is recommended that: (1) Sludge settling and rheology during washing of the forthcoming Sludge Batch 5 qualification sample be monitored closely and communicated to the Tank Farm. (2) SRNL receive a sample of Tank 51 after all chemical additions have been made and prior to the final Sludge Batch 5 decant for rheological assessment. Rheology versus wt% insoluble solids will be performed to determine the maximum amount of decant prior to the Tank 51 to Tank 40 transfer. (3) As a result of the problem with measuring total base and subsequently under-calculating acid for the DWPF CPC processing of the post aluminum dissolution sludge; (4) Studies to develop understanding of how the sludge titrates (i.e., why different titration methods yield different results) should be performed. (5) Simulants that better match the properties of post aluminum dissolution sludge should be developed. (6) Work on developing an acid calculation less dependant on the total base measurement should be continued
A Blueprint to Address Research Gaps in the Development of Biomarkers for Pediatric Tuberculosis
Childhood tuberculosis contributes significantly to the global tuberculosis disease burden but remains challenging to diagnose due to inadequate methods of pathogen detection in paucibacillary pediatric samples and lack of a child-specific host biomarker to identify disease. Accurately diagnosing tuberculosis in children is required to improve case detection, surveillance, healthcare delivery, and effective advocacy. In May 2014, the National Institutes of Health convened a workshop including researchers in the field to delineate priorities to address this research gap. This blueprint describes the consensus from the workshop, identifies critical research steps to advance this field, and aims to catalyze efforts toward harmonization and collaboration in this are
First insights into the phylogenetic diversity of Mycobacterium tuberculosis in Nepal
BACKGROUND: Tuberculosis (TB) is a major public health problem in Nepal. Strain variation in Mycobacterium tuberculosis may influence the outcome of TB infection and disease. To date, the phylogenetic diversity of M. tuberculosis in Nepal is unknown. METHODS AND FINDINGS: We analyzed 261 M. tuberculosis isolates recovered from pulmonary TB patients recruited between August 2009 and August 2010 in Nepal. M. tuberculosis lineages were determined by single nucleotide polymorphisms (SNP) typing and spoligotyping. Drug resistance was determined by sequencing the hot spot regions of the relevant target genes. Overall, 164 (62.8%) TB patients were new, and 97 (37.2%) were previously treated. Any drug resistance was detected in 50 (19.2%) isolates, and 16 (6.1%) were multidrug-resistant. The most frequent M. tuberculosis lineage was Lineage 3 (CAS/Delhi) with 106 isolates (40.6%), followed by Lineage 2 (East-Asian lineage, includes Beijing genotype) with 84 isolates (32.2%), Lineage 4 (Euro-American lineage) with 41 (15.7%) isolates, and Lineage 1 (Indo-Oceanic lineage) with 30 isolates (11.5%). Based on spoligotyping, we found 45 different spoligotyping patterns that were previously described. The Beijing (83 isolates, 31.8%) and CAS spoligotype (52, 19.9%) were the dominant spoligotypes. A total of 36 (13.8%) isolates could not be assigned to any known spoligotyping pattern. Lineage 2 was associated with female sex (adjusted odds ratio [aOR] 2.58, 95% confidence interval [95% CI] 1.42-4.67, p = 0.002), and any drug resistance (aOR 2.79; 95% CI 1.43-5.45; p = 0.002). We found no evidence for an association of Lineage 2 with age or BCG vaccination status. CONCLUSIONS: We found a large genetic diversity of M. tuberculosis in Nepal with representation of all four major lineages. Lineages 3 and 2 were dominating. Lineage 2 was associated with clinical characteristics. This study fills an important gap on the map of the M. tuberculosis genetic diversity in the Asian reg
Two new rapid SNP-typing methods for classifying Mycobacterium tuberculosis complex into the main phylogenetic lineages
There is increasing evidence that strain variation in Mycobacterium tuberculosis complex (MTBC) might influence the outcome of tuberculosis infection and disease. To assess genotype-phenotype associations, phylogenetically robust molecular markers and appropriate genotyping tools are required. Most current genotyping methods for MTBC are based on mobile or repetitive DNA elements. Because these elements are prone to convergent evolution, the corresponding genotyping techniques are suboptimal for phylogenetic studies and strain classification. By contrast, single nucleotide polymorphisms (SNP) are ideal markers for classifying MTBC into phylogenetic lineages, as they exhibit very low degrees of homoplasy. In this study, we developed two complementary SNP-based genotyping methods to classify strains into the six main human-associated lineages of MTBC, the 'Beijing' sublineage, and the clade comprising Mycobacterium bovis and Mycobacterium caprae. Phylogenetically informative SNPs were obtained from 22 MTBC whole-genome sequences. The first assay, referred to as MOL-PCR, is a ligation-dependent PCR with signal detection by fluorescent microspheres and a Luminex flow cytometer, which simultaneously interrogates eight SNPs. The second assay is based on six individual TaqMan real-time PCR assays for singleplex SNP-typing. We compared MOL-PCR and TaqMan results in two panels of clinical MTBC isolates. Both methods agreed fully when assigning 36 well-characterized strains into the main phylogenetic lineages. The sensitivity in allele-calling was 98.6% and 98.8% for MOL-PCR and TaqMan, respectively. Typing of an additional panel of 78 unknown clinical isolates revealed 99.2% and 100% sensitivity in allele-calling, respectively, and 100% agreement in lineage assignment between both methods. While MOL-PCR and TaqMan are both highly sensitive and specific, MOL-PCR is ideal for classification of isolates with no previous information, whereas TaqMan is faster for confirmation. Furthermore, both methods are rapid, flexible and comparably inexpensive
The Truth, the Whole Truth, and Nothing but the Truth: A Pragmatic Guide to Assessing Empirical Evaluations
An unsound claim can misdirect a field, encouraging the pursuit of unworthy ideas and the abandonment of promising ideas. An inadequate description of a claim can make it difficult to reason about the claim, for example to determine whether the claim is sound. Many practitioners will acknowledge the threat of un- sound claims or inadequate descriptions of claims to their field. We believe that this situation is exacerbated and even encouraged by the lack of a systematic approach to exploring, exposing, and addressing the source of unsound claims and poor exposition.
This paper proposes a framework that identifies three sins of reasoning that lead to unsound claims and two sins of exposition that lead to poorly described claims. Sins of exposition obfuscate the objective of determining whether or not a claim is sound, while sins of reasoning lead directly to unsound claims.
Our framework provides practitioners with a principled way of critiquing the integrity of their own work and the work of others. We hope that this will help individuals conduct better science and encourage a cultural shift in our research community to identify and promulgate sound claims
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DEMONSTRATION OF THE DWPF FLOWSHEET IN THE SRNL SHIELDED CELLS USING ARP PRODUCT SIMULANT AND SB4 TANK 40 SLUDGE SLURRY
The radioactive startup of two new SRS processing facilities, the Actinide Removal Process (ARP) and the Modular Caustic-Side-Solvent-Extraction Unit (MCU) will add two new waste streams to the Defense Waste Processing Facility (DWPF). The ARP will remove actinides from the 5.6 M salt solution resulting in a sludge-like product that is roughly half monosodium titanate (MST) insoluble solids and half sludge insoluble solids. The ARP product will be added to the Sludge Receipt and Adjustment Tank (SRAT) at boiling and dewatered prior to pulling a SRAT receipt sample. The cesium rich MCU stream will be added to the SRAT at boiling after both formic and nitric acid have been added and the SRAT contents concentrated to the appropriate endpoint. A concern was raised by an external hydrogen review panel that the actinide loaded MST could act as a catalyst for hydrogen generation (Mar 15, 2007 report, Recommendation 9). Hydrogen generation, and it's potential to form a flammable mixture in the off-gas, under SRAT and Slurry Mix Evaporator (SME) processing conditions has been a concern since the discovery that noble metals catalyze the decomposition of formic acid. Radiolysis of water also generates hydrogen, but the radiolysis rate is orders of magnitude lower than the noble metal catalyzed generation. As a result of the concern raised by the external hydrogen review panel, hydrogen generation was a prime consideration in this experiment. Testing was designed to determine whether the presence of the irradiated ARP simulant containing MST caused uncontrolled or unexpected hydrogen production during experiments simulating the DWPF Chemical Process Cell (CPC) due to activation of titanium. A Shielded Cells experiment, SC-5, was completed using SB4 sludge from Tank 405 combined with an ARP product produced from simulants by SRNL researchers. The blend of sludge and MST was designed to be prototypic of planned DWPF SRAT and SME cycles. As glass quality was not an objective in this experiment, no vitrification of the SME product was completed. The results from this experiment were compared to the results from experiment SC-1, a similar experiment with SB4 sludge without added ARP product. This report documents: (1) The preparation and subsequent composition of the ARP product. (2) The preparation and subsequent compositional characterization of the SRAT Receipt sample. Additional details will be presented concerning the noble metal concentration of the ARP product and the SRAT receipt sample. Also, calculations related to the amount of formic and nitric acid added during SRAT processing will be presented as excess formic acid will lead to additional hydrogen generation. (3) Highlights from processing during the SRAT cycle and SME cycle (CPC processing). Hydrogen generation will be discussed since this was the prime objective for this experiment. (4) A comparison of CPC processing between SC-1 (without ARP simulant) and SC-5. This work was controlled by a Task Technical and Quality Assurance Plan (TTQAP)6, and analyses were guided by an Analytical Sample Support Matrix (ASSM)7. This Research and Development (R&D) was completed to support operation of DWPF
Induction of lymphokine-activated killer activity in rat splenocyte cultures: The importance of 2-mercaptoethanol and indomethacin
The role of 2-mercaptoethanol and indomethacin in the induction of lymphokine-activated killer (LAK) activity by interleukin-2 (IL-2) in rat splenocyte cultures was investigated. Spleens from 4-month-old male rats of five different strains were tested. Splenocytes were cultured for 3-5 days in the presence of IL-2 (1000 U/ml) and LAK activity was assessed by 4-h51Cr release assays with P815 and YAC-1 cells as targets. LAK activity could be induced by IL-2 in splenocytes from all rat strains, but only when 2-mercaptoethanol was present in the culture medium. Optimal LAK activity was induced when the 2-mercaptoethanol concentration in splenocyte cultures was at least 5 μM. Different rat strains showed differences in levels of in vitro induction of LAK activity. In the presence of 2-mercaptoethanol the level of LAK activity induced by IL-2 was high in BN and Lewis rats, intermediate in Wistar and Wag rats, and low in DZB rats. In the absence of 2-mercaptoethanol no or minimal LAK activity was induced. Furthermore we observed that addition of 50 μm indomethacin to the culture medium in the presence of 2-mercaptoethanol augmented the induction of LAK activity to some extent. In the absence of 2-mercaptoethanol, addition of indomethacin resulted only in low levels or no induction of LAK activity. We conclude that for optimal induction of LAK activity by IL-2 in rat splenocyte cultures 2-mercaptoethanol is essential, while indomethacin can only marginally further improve this induction
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