bluuebunny/crossref_metadata_2025 huggingface dataset:
Growth and Nitrogen Fixation in High‐Yielding Soybean: Impact of Nitrogen Fertilization
Authors: Salvagiotti Fernando , Specht James E. , Cassman Kenneth G. , Walters Daniel T. , Weiss Albert , Dobermann Achim
Published: July 2009

In high‐yielding soybean [Glycine max (L.) Merr.] environments, N uptake during seed‐filling may be constrained when the late‐season decline in biological nitrogen fixation (BNF) is coupled with insufficient soil N. Three N‐fertilization strategies were compared with a control (N0) on soybeans in 2006 and 2007 in a high‐yield soybean‐maize (Zea mays L.) rotation experiment established in 1999. Our objective was to identify strategies for overcoming a late‐season N‐supply limitation to maximal seed yield coupled with N fertilizer‐induced reduction in BNF. In the N0 treatment, no N was applied, but in each N fertilization strategy, 180 kg N ha−1 were applied as (i) polymer‐coated controlled‐release urea placed 20 cm below the soil surface before planting (NLu); (ii) ammonium nitrate split‐applied to the surface before planting and at V6 (early application, NEa), or (iii) ammonium nitrate applied to the surface at R5 (NLa). The ureide method was used to estimate BNF. The N0 yield was 4850 kg ha−1, but the mean of the three N‐applied treatments had 228 kg ha−1 (5%) higher yields. The N0 N uptake was 411 kg ha−1, but it was 36 kg ha−1 (9%) greater in the mean of the three N treatments. Nitrogen uptake attributable to BNF in the N0, NLu, NEa, and NLa treatments was 50, 46, 32, and 38% of total N accumulation, respectively. Yield maximization and mitigation of N fertilizer‐induced reduction of BNF were both achievable when soybean plants acquired N from a slow‐release urea applied before planting in a deep band located below the root nodulation zone.
Concordance Correlation for Model Performance Assessment: An Example with Reference Evapotranspiration Observations
Authors: Meek David W. , Howell Terry A. , Phene Claude J.
Published: July 2009

The assessment procedures for agronomic model performance are often arbitrary and unhelpful. An omnibus analysis, the concordance correlation coefficient (rc), is widely used in many other sciences. This work illustrates model assessment with two rc measures accompanied with a mean‐difference (MD) plot and a distribution comparison. Each rc is an adjusted value of the usual Pearson correlation coefficient, r, assuming the exact relationship observations = predictions The adjustments use a scale shift, u, and a location shift, v Both of these measures also can indicate the similarity of the two variables' distributions; however, a formal test, the Kolmorgov‐Smirnov D statistic, is used to statistically compare the distributions. Daily evapotranspiration data (ET0) from a published study are compared with estimates from two possible weather observation based models. Although the first model has slightly lower r than the second (0.980 vs. 0.982), its predictions reasonably agree with observations by having comparatively small location and scale shifts [(u = 0.025, v = 1.10, D = 0.12 (p ≤ 0.86)] and, consequently, a higher rc (0.975 vs. 0.946). Results for the second model are comparatively unacceptable having larger scale and location shifts (u = 0.215, v = 1.19, D = 0.28 [p ≤ 0.04]) with the bias ≠ 0 (p ≤ 0.05) as clearly shown in the associated MD plot. Researchers should consider using rc with an MD plot and distribution comparison in their model assessment toolkit because, together, they can provide a simple and sound probability based omnibus test as well as add useful insight.
Crop Rotation and Nitrogen Input Effects on Soil Fertility, Maize Mineral Nutrition, Yield, and Seed Composition
Authors: Riedell Walter E. , Pikul Joseph L. , Jaradat Abdullah A. , Schumacher Thomas E.
Published: July 2009

Knowledge of complex relationships between soils, crops, and management practices is necessary to develop sustainable agricultural production systems. Objectives were to determine how maize (Zea mays L.) would respond to monoculture (C‐C), 2‐yr rotation (C‐S) with soybean [Glycine max (L.) Merr.], or 4‐yr rotation (C‐S‐W/A‐A) with soybean, wheat (Triticum aestivum L.), and alfalfa (Medicago sativa L.) under different N input levels. We evaluated N fertilizer input (8.5 or 5.3 Mg/ha yield goal, or no N) and crop rotation (C‐C, C‐S, or C‐S‐W/A‐A) treatment effects on soil minerals (N, P, K, S, Ca, Mg, Fe, Mn, and Zn) and their subsequent effect on shoot dry weight and mineral concentrations, grain yield, and grain composition (oil, starch, and mineral concentrations) using univariate and multivariate statistical tests. Soil under C‐S‐W/A‐A rotation had greater NO3–N and less extractable P than other rotations. Significant input × rotation interactions revealed that shoot concentrations of N, Ca, and Mg were less while P, K, and Zn were greater at no N input for the C‐C rotation compared with other N input/rotation treatments. Increased soil NO3–N, increased plant Ca concentration, and increased grain N and grain S concentrations were most important in differentiating C‐S‐W/A‐A rotation from C‐C and C‐S rotation treatments. No N input resulted in less yield and kernel N concentration within the C‐C and C‐S rotations but not C‐S‐W/A‐A. Thus, growing maize in extended rotations that include forage legumes may be a more sustainable practice than growing maize in either monoculture or 2‐yr rotation with soybean.
Potato Response to a Polymer‐Coated Urea on an Irrigated, Coarse‐Textured Soil
Authors: Wilson Melissa L. , Rosen Carl J. , Moncrief John F.
Published: July 2009

Controlled release fertilizers, especially polymer‐coated urea (PCU), have been shown to reduce nitrate (NO3) leaching while maintaining potato (Solanum tuberosum L.) yields, but cost has been prohibitive. A new type of PCU (Environmentally Smart Nitrogen, Agrium, Inc., Calgary, AB) is less costly than previous PCUs, but its effectiveness on potato production has not been extensively studied. A 2‐yr field study was conducted on loamy sand to evaluate the effect of this PCU on Russet Burbank tuber yield and to determine if it is economically comparable to soluble N sources. Several N rates of PCU applied at emergence were compared with two split applications of soluble N at equivalent rates. Additional treatments examined N application timing of PCU and a fertigation simulation with urea/ammonium nitrate. Petioles and midseason soil samples were collected to determine N status during the season. Overall, PCU and soluble N at equivalent N rates were found to have similar total and grade A yields and net monetary returns. The optimal N rate that resulted in maximum net returns was 251 and 236 kg N ha−1 as soluble N and PCU, respectively. Petiole NO3 concentrations were typically higher with soluble N early in the season and higher with PCU later in the season. Soil NO3 determined in samples collected in late June was found to be a better predictor of yield and potential N need than those collected in mid‐ to late July. Overall, PCU may reduce or eliminate the need for split applications of N on coarse‐textured soils.
Seeding Rate and Planting Arrangement Effects on Growth and Weed Suppression of a Legume‐Oat Cover Crop for Organic Vegetable Systems
Authors: Brennan Eric B. , Boyd Nathan S. , Smith Richard F. , Foster Phil
Published: July 2009

Winter cover crops can add soil organic matter, improve nutrient cycling, and suppress weeds in organic vegetable systems. A 2‐yr study was conducted on organic farms in Salinas and Hollister, CA, to evaluate the effect of seeding rate (SR) and planting arrangement on cover crop density, ground cover, and cover crop and weed dry matter (DM) with a mixed cover crop. The mix contained legumes (35% Vicia faba L., bell bean; 15% Vicia dasycarpa Ten., woolypod vetch; 15% Vicia benghalensis L., purple vetch; and 25% Pisum sativum L., pea) and 10% oat (Avena sativa L.) by seed weight. Three SRs (112, 224, and 336 kg ha−1) and two planting arrangements (one‐way versus grid pattern) were evaluated. Planting arrangement had no effect on the variables measured. When weeds were abundant, weed DM declined linearly with increasing SR from approximately 300 kg ha−1 at the low SR to <100 kg ha−1 at the high SR. Increasing SR increased oat and legume DM early in the season, but did not affect final cover crop DM that ranged from 7 to 12 Mg ha−1. Year affected final cover crop DM production at both sites. The legume DM portion of the total cover crop declined through the season but varied between sites and year, probably due to soil and climatic differences. Higher SRs may be cost effective because weed control is expensive and cover crop seed is a relatively small component of cover cropping costs in this region.
Potential Agricultural Uses of Flue Gas Desulfurization Gypsum in the Northern Great Plains
Authors: DeSutter T. M. , Cihacek L. J.
Published: July 2009

Flue gas desulfurization gypsum (FGDG) is a byproduct from the combustion of coal for electrical energy production. Currently, FGDG is being produced by 15 electrical generating stations in Alabama, Florida, Indiana, Iowa, Kentucky, Ohio, North Carolina, South Carolina, Tennessee, Texas, and Wisconsin. Much of this byproduct is used in the manufacturing of wallboard. The National Network for Use of FGDG in Agriculture was initiated to explore alternative uses of this byproduct. In the northern Great Plains (North Dakota, South Dakota, and Montana), FGDG has the potential to be used as a Ca or S fertilizer, as an acid soil ameliorant, and for reclaiming or mitigating sodium‐affected soils. Greater than 1.4 million Mg of FGDG could initially be used in these states for these purposes. Flue gas desulfurization gypsum can be an agriculturally important resource for helping to increase the usefulness of problem soils and to increase crop and rangeland production. Conducting beneficial use audits would increase the public awareness of this product and help identify to coal combustion electrical generating stations the agriculturally beneficial outlets for this byproduct.
Corn Grain Yields and Yield Stability in Four Long‐Term Cropping Systems
Authors: Grover K. K. , Karsten H. D. , Roth G. W.
Published: July 2009

Most long‐term studies evaluate only average crop yields and overlook year‐to‐year yield variability, which could be highly significant. Our objectives were to evaluate the impact of long‐term cropping systems and fertility management on corn (Zea mays L.) yield and yield stability. Cropping systems were (i) CC, continuous corn; (ii) CS, corn‐soybean [Glycine max (L) Merr.]; (iii) 4C4A, 4 yr corn‐4 yr alfalfa (Medicago sativa L.); and (iv) COW2RT, corn‐oat (Avena sativa L.)/winter wheat (Triticum aestivum L.)‐2 yr red clover (Trifolium pratense L.)/timothy (Phleum pratense L.). Fertility regimes were inorganic, or manure based on crop N or P requirements. Averaged across fertility regimes, mean corn yields in 4C4A and COW2RT were 10 to 12% higher than CC, and 7% higher in 4C4A than CS. Yield trends were similar (0.28 Mg ha−1 yr−1) among all cropping systems. Coefficient of variation (CV) analysis indicated that yield variability was highest in CC (CV = 28%) and lowest in 4C4A (CV = 21%) across fertility regimes. Regression analysis indicated that response of corn yield to the environment mean did not differ among the cropping systems within inorganic and P‐based manure fertility and corn yielded lower in CC than in 4C4A and COW2RT systems. Under N‐based manure fertility, yield was lower in CC than in other systems in the poorest‐yielding year, but similar in the highest‐yielding year. Results suggest that, on average, rotations are likely to produce higher yields than CC across fertility regimes. In high‐yielding years with N‐based manure fertility, however, corn yield in monoculture may be similar to that in rotations.
Nitrogen Recommendations for Corn: An On‐The‐Go Sensor Compared with Current Recommendation Methods
Authors: Schmidt John P. , Dellinger Adam E. , Beegle Doug B.
Published: July 2009

Precision agriculture technologies provide the capability to spatially vary N fertilizer applied to corn (Zea mays L.), potentially improving N use efficiency. The focus of this study was to evaluate the potential of improving N recommendations based on crop canopy reflectance. Corn was grown at four field sites in each of 2 yr in Centre County, Pennsylvania. Preplant treatments included: zero fertilizer, 56 kg N ha−1, and manure. Split‐plot treatments included the following N sidedress rates as NH4NO3: 0, 22, 45, 90, 135, 180, and 280 kg N ha−1, and one at‐planting N rate of 280 kg N ha−1. Light energy reflectance (590 and 880 nm), chlorophyll meter (SPAD) measurements, and the presidedress NO3 test (PSNT) results were obtained at sidedress. The late‐season stalk NO3 (LSSN) test was determined. The economic optimum nitrogen rate (EONR) was determined based on grain yield response to sidedress N rates. Relative green normalized difference vegetation index (GNDVI) and relative SPAD were based on relative measurements from the zero sidedress treatment to the 280 kg N ha−1 at‐planting treatment. The EONR from 24 preplant treatment–site combinations was related to relative GNDVI (R2 = 0.76), the PSNT (R2 = 0.78), relative SPAD (R2 = 0.72), and the LSSN test (R2 = 0.64), suggesting that relative GNDVI was as good an indicator of EONR as these other, more conventional tests. Because relative GNDVI can be obtained simultaneously with a sidedress N fertilizer application, the potential to accommodate within‐field spatial and season‐to‐season temporal variability in N availability should improve N management decisions for corn production.
Oil Content and Saturated Fatty Acids in Sunflower as a Function of Planting Date, Nitrogen Rate, and Hybrid
Authors: Zheljazkov Valtcho D. , Vick Brady A. , Baldwin Brian S. , Buehring Normie , Astatkie Tess , Johnson Billy
Published: July 2009

The fatty acids (FA) composition of sunflower (Helianthus annuus L.) determines its uses and health effects on humans, while oil content determines the price paid to producers. The hypothesis of this study was that agronomic factors (genotype, planting date, and N rate) will affect total saturated fatty acid (TSFA) concentration and oil content of sunflower. Additionally, Mississippi‐grown sunflower will have a different FA composition than the original seeds produced in more northern latitudes and used for planting. A field experiment was performed in four locations in Mississippi (Newton, Starkville, and two locations in Verona) to assess the effect of planting date (20 April, 20 May, and 20 June), N application rate (0, 67, 134, and 202 kg N ha−1) and genotype (hybrid, DKF3875, DKF2990, DKF3510, and DKF3901) on sunflower seed oil content and composition. The TSFA and oil content were significantly affected by planting date, hybrid, and N rate. Overall, later planting dates increased TSFA relative to the first planting, and in most instances TSFA concentrations in sunflower from the third planting was higher than in seeds from the second. Generally, the first planting date provided the highest oil content of the four hybrids, the second planting reduced oil content, while the third was not different from the second. Our results suggest that an earlier planting date may reduce the TSFA and increase oil content of sunflower in Mississippi. Regarding individual FA, overall, palmitic (16:0) and stearic acid (18:0) concentrations in sunflower seed grown in Mississippi from the first planting were reduced relative to the respective concentrations in the original seed. Later planting tended to increase these two acids relative to the first planting and relative to the original seed. The three minor saturated fatty acids (SFA), arachidic (20:0), behenic (22:0), and lignoceric acid (24:0) followed a similar pattern. This study demonstrated that agricultural factors such as planting date, hybrid, and N rate may significantly modify FA composition and oil content of sunflower grown in Mississippi, suggesting that these could be used as management tools for decreased TSFA and increased oil content.
Single Irrigation Can Achieve Relatively High Production and Water Use Efficiency of Siberian Wildrye Grass in the Semiarid Agropastoral Ecotone of North China
Authors: Wang Hao , Li Zizhong , Gong Yuanshi , Wang Zhongyan , Huang Ding
Published: July 2009

Siberian wildrye grass (Elymus sibiricus L.) is widely planted in the agropastoral ecotone of North China (APENC). Scheduled irrigation is an important approach to increase the forage yield in this semiarid region. Based on field experiments conducted in Bashang Plateau in APENC during 2002 to 2004, we studied the feasibility of applying single irrigation (SI) to increase forage yield by bringing the soil water storage in the root zone (0–60 cm) to field capacity at the elongating stage. The results showed that Siberian wildrye grass consumed water most rapidly during the elongating stage. With 48 to 62 mm of water applied during elongating stage, forage yields reached 6000 kg ha−1, a 110% increase compared with no irrigation (NI). With full irrigation (FI) in the growing season, forage yield was only increased by 10% compared with that under SI. The average water use efficiency (WUE) under SI was 1.9 kg m−3, a 76% increase compared with NI or a 10% increase compared with FI. The average irrigation water use efficiency (IWUE) under SI was 10.8 kg m−3 which was almost three times that under FI. Therefore, a single irrigation can be a simple agricultural practice for local farmers, and has great potential to contribute to sustainability of semiarid APENC. In addition, forage yield and WUE showed a quadratic trend with total evapotranspiration (ET). The maximum forage yield in this semiarid area was about 6900 kg ha−1 at 390 mm ET, whereas the maximum WUE was 1.9 kg m−3 at 360 mm ET.
A Variant in the KCNQ1 Gene Predicts Future Type 2 Diabetes and Mediates Impaired Insulin Secretion
Authors: Jonsson Anna , Isomaa Bo , Tuomi Tiinamaija , Taneera Jalal , Salehi Albert , Nilsson Peter , Groop Leif , Lyssenko Valeriya
Published: July 2009

OBJECTIVE

Two independent genome-wide association studies for type 2 diabetes in Japanese subjects have recently identified common variants in the KCNQ1 gene that are strongly associated with type 2 diabetes. Here we studied whether a common variant in KCNQ1 would influence BMI as well as insulin secretion and action and predict future type 2 diabetes in subjects from Sweden and Finland.

RESEARCH DESIGN AND METHODS

Risk of type 2 diabetes conferred by KCNQ1 rs2237895 was studied in 2,830 type 2 diabetic case subjects and 3,550 control subjects from Sweden (Malmö Case-Control) and prospectively in 16,061 individuals from the Malmö Preventive Project (MPP). Association between genotype and insulin secretion/action was assessed cross- sectionally in 3,298 nondiabetic subjects from the Prevalence, Prediction and Prevention of Diabetes (PPP)-Botnia Study and longitudinally in 2,328 nondiabetic subjects from the Botnia Prospective Study (BPS). KCNQ1 expression (n = 18) and glucose-stimulated insulin secretion (n = 19) were measured in human islets from nondiabetic cadaver donors.

RESULTS

The C-allele of KCNQ1 rs2237895 was associated with increased risk of type 2 diabetes in both the Malmö Case-Control (odds ratio 1.23 [95% CI 1.12–1.34]; P = 5.6 × 10−6) and the prospective (1.14 [1.06–1.22]; P = 4.8 × 10−4) studies. Furthermore, the C-allele was associated with decreased insulin secretion (corrected insulin response [CIR] P = 0.013; disposition index [DI] P = 0.013) in the PPP-Botnia Study and in the BPS at baseline (CIR P = 3.6 × 10−4; DI P = 0.0058) and after follow-up (CIR P = 0.0018; DI P = 0.0030). C-allele carriers showed reduced glucose-stimulated insulin secretion in human islets (P = 2.5 × 10−6).

CONCLUSIONS

A common variant in the KCNQ1 gene is associated with increased risk of future type 2 diabetes in Scandinavians, which partially can be explained by an effect on insulin secretion.
Functional Brain Connectivity and Neurocognitive Functioning in Patients With Long-Standing Type 1 Diabetes With and Without Microvascular Complications
Authors: van Duinkerken Eelco , Klein Martin , Schoonenboom Niki S.M. , Hoogma Roel P.L.M. , Moll Annette C. , Snoek Frank J. , Stam Cornelis J. , Diamant Michaela
Published: July 2009

OBJECTIVE

Hyperglycemia-associated microvascular disease may underlie changes in cerebral functioning and cognitive performance in patients with type 1 diabetes. Functional connectivity, an indicator of functional interactions and information exchange between brain regions, provides a measure of cerebral functioning. This study addresses functional connectivity and cognition in type 1 diabetic patients with and without proliferative retinopathy, relative to healthy control subjects, using magnetoencephalography.

RESEARCH DESIGN AND METHODS

Fluctuations in magnetic field at scalp for Δ, θ, lower and upper α, β, and lower and upper γ frequency bands were measured using magnetoencephalography. Synchronization likelihood, a measure of functional connectivity, was computed. Using neuropsychological tests, cognitive functioning was assessed and its associations with functional connectivity were determined.

RESULTS

Compared with control subjects, type 1 diabetic patients performed poorer on general cognitive ability, information processing speed, and motor speed, irrespective of their microvascular complication status. Functional connectivity, however, was lowest for type 1 diabetic patients with retinopathy, compared with type 1 diabetic patients without microvascular complications and control subjects, whereas type 1 diabetic patients without microvascular complications showed an increase relative to control subjects. Positive associations were found between functional connectivity and executive functioning, memory, information processing speed, motor speed, and attention.

CONCLUSIONS

Compared with healthy control subjects, functional connectivity and cognition differed in type 1 diabetic patients irrespective of microvascular complication status, indicating that chronic hyperglycemia, among other factors, may negatively affect brain functioning even before microvascular damage becomes manifest. The association found between synchronization likelihood and cognition suggests functional connectivity plays a significant role in cognitive functioning.
Dyssegmental Dysplasia with Bone Entrapment and Visceral Ramifications
Authors: Wainwright Helen , Beighton Peter
Published: July 2009

A stillborn neonate had the typical clinical and radiologic manifestations of dyssegmental dysplasia, an autosomal recessive genetic disorder. The diagnosis was supported by histologic demonstration of the characteristic ballooned chondrocytes in the growth plate and spaces filled with mucoid material in the resting cartilage. Autopsy revealed entrapment of the femoral heads by bone overgrowth in the acetabulum. This notable feature, which has apparently not previously been documented, explained the articular rigidity, which is a significant clinical manifestation. Horizontal grooves on the anterior surface of the spleen were another unusual finding. Our observations further emphasize the importance of comprehensive autopsy in the determination of the pathogenesis of the clinical features and the range of phenotypic expression of an underlying mutation in an unusual genetic disorder.
Additive SMILES-Based Carcinogenicity Models: Probabilistic Principles in the Search for Robust Predictions
Authors: Toropov Andrey A. , Toropova Alla P. , Benfenati Emilio
Published: July 2009

Optimal descriptors calculated with the simplified molecular input line entry system (SMILES) have been utilized in modeling of carcinogenicity as continuous values (logTD50). These descriptors can be calculated using correlation weights of SMILES attributes calculated by the Monte Carlo method. A considerable subset of these attributes includes rare attributes. The use of these rare attributes can lead to overtraining. One can avoid the influence of the rare attributes if their correlation weights are fixed to zero. A function, limS, has been defined to identify rare attributes. The limS defines the minimum number of occurrences in the set of structures of the training (subtraining) set, to accept attributes as usable. If an attribute is present less than limS, it is considered “rare”, and thus not used. Two systems of building up models were examined: 1. classic training-test system; 2. balance of correlations for the subtraining and calibration sets (together, they are the original training set: the function of the calibration set is imitation of a preliminary test set). Three random splits into subtraining, calibration, and test sets were analysed. Comparison of abovementioned systems has shown that balance of correlations gives more robust prediction of the carcinogenicity for all three splits (split 1: rtest2=0.7514, stest=0.684; split 2: rtest2=0.7998, stest=0.600; split 3: rtest2=0.7192, stest=0.728).
Compostability of Co-Extruded Starch/Poly(Lactic Acid) Polymeric Material Degradation in an Activated Inert Solid Medium
Authors: Copinet Alain , Legin-Copinet Estelle , Erre Damien
Published: July 2009

The aim of this work was to estimate the biodegradation of a co-extruded starch/poly(lactic acid) polymeric material using a vermiculite based inert solid medium which could simulate compost medium and enable us to achieve complete carbon balances. At the end of the test the mineralisation rate was compared to those obtained for co-extruded starch/poly(lactic acid) polymeric material degradation in compost. It was shown that the mineralisation rate after 45 days of degradation was similar in activated vermiculite medium to the one in compost. A protocol for both extraction and quantification of the carbon included in the different degradation by-products was proposed and the carbon balance of the polymer degradation was followed during the test with a satisfactory accuracy. As the non-degraded PLA and starch material had been retrieved during the test, the evolution of the glass transition temperature and the molecular weight of PLA could be followed. A two-step degradation mechanism was highlighted in inert solid medium, showing the fundamental role of abiotic reactions for PLA degradation in compost.
Label-Free Electrical Detection Using Carbon Nanotube-Based Biosensors
Authors: Maehashi Kenzo , Matsumoto Kazuhiko
Published: July 2009

Label-free detections of biomolecules have attracted great attention in a lot of life science fields such as genomics, clinical diagnosis and practical pharmacy. In this article, we reviewed amperometric and potentiometric biosensors based on carbon nanotubes (CNTs). In amperometric detections, CNT-modified electrodes were used as working electrodes to significantly enhance electroactive surface area. In contrast, the potentiometric biosensors were based on aptamer-modified CNT field-effect transistors (CNTFETs). Since aptamers are artificial oligonucleotides and thus are smaller than the Debye length, proteins can be detected with high sensitivity. In this review, we discussed on the technology, characteristics and developments for commercialization in label-free CNT-based biosensors.
Mitomycins syntheses: a recent update
Authors: Andrez Jean-Christophe
Published: July 2009

Mitomycins are a class of very potent antibacterial and anti-cancer compounds having a broad activity against a range of tumours. They have been used in clinics since the 1960’s, and the challenges represented by their total synthesis have challenged generations of chemists. Despite these chemical and medicinal features, these compounds, in racemic form, have succumbed to total synthesis only four times over the last 30 years.
Immigration, employment relations, and health: Developing a research agenda
Authors: Benach Joan , Muntaner Carles , Chung Haejoo , Benavides Fernando G.
Published: July 2009

Background

International migration has emerged as a global issue that has transformed the lives of hundreds of millions of persons. Migrant workers contribute to the economic growth of high‐income countries often serving as the labour force performing dangerous, dirty and degrading work that nationals are reluctant to perform.

Methods

Critical examination of the scientific and “grey” literatures on immigration, employment relations and health.

Results

Both lay and scientific literatures indicate that public health researchers should be concerned about the health consequences of migration processes. Migrant workers are more represented in dangerous industries and in hazardous jobs, occupations and tasks. They are often hired as labourers in precarious jobs with poverty wages and experience more serious abuse and exploitation at the workplace. Also, analyses document migrant workers' problems of social exclusion, lack of health and safety training, fear of reprisals for demanding better working conditions, linguistic and cultural barriers that minimize the effectiveness of training, incomplete OHS surveillance of foreign workers and difficulty accessing care and compensation when injured. Therefore migrant status can be an important source of occupational health inequalities.

Conclusions

Available evidence shows that the employment conditions and associated work organization of most migrant workers are dangerous to their health. The overall impact of immigration on population health, however, still is poorly understood and many mechanisms, pathways and overall health impact are poorly documented. Current limitations highlight the need to engage in explicit analytical, intervention and policy research. Am. J. Ind. Med. 53:338–343, 2010. © 2009 Wiley‐Liss, Inc.
Instrumental analysis of gas hydrates properties
Authors: Rojas Y. , Lou X.
Published: July 2009

Gas hydrates attracted intense research interest when it was first recognised some 70 years ago that they were responsible for the blockage of flow lines, valves and well heads, thereby causing great loss of production and other severe safety hazards to the oil and gas industry. After many decades, these compounds are still the topic of research activities in various multi‐disciplinary fields, including chemical and petroleum engineering, earth and geophysics, chemistry and environmental sciences. This is not only due to the great impact that these compounds have on the oil and gas industry, but also to the potential applications they have in many evolving areas, including, but not only, natural gas storage and transportation, carbon dioxide sequestration, and sea‐water desalination. It is generally accepted that gas hydrates represent the largest source of hydrocarbons on earth, something which has not been appreciated until only recently.

Management, either prevention or application or both, of gas hydrates requires a complete knowledge and understanding of the formation, decomposition and inhibition mechanisms of gas hydrates, which in turn demands advanced experimental methods and instrumental techniques for gas hydrate characterisation. This paper reviews a broad range of techniques that have been used for natural gas hydrate characterisation. It includes the basic physical science principles of each method and the gas hydrate properties that each method is capable of detecting, including some modern instrumental analyses that enable direct determination of gas hydrate phases and possible measurement of molecular interactions within the fluid phases. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Hydrodenitrogenation of quinoline and its intermediates over sulfided NiW/γ‐Al2O3 in the absence and presence of H2S
Authors: Luan YeZhi , Zhang Qiumin , He Demin , Guan Jun , Liang Changhai
Published: July 2009

Hydrodenitrogenation (HDN) reactions of quinoline and its intermediates were carried out at 300–420 °C and 2–6 MPa over sulfided NiW/γ‐Al2O3 in the absence and presence of H2S. The results show that temperature and pressure have a drastic effect on nitrogen removal and production distribution in the HDN of quinoline. 1,2,3,4‐tetrahydroquinoline THQ1 mainly underwent dehydrogenation to quinoline and then hydrogenated to 5,6,7,8‐tetrahydroquinoline (THQ5), and decahydroquinoline (DHQ) following by ring opening elimination to give 2‐propylcyclohexylamine (PCHA) and hydrocarbons. The HDN of THQ5 mainly proceeded the path of DHQ–PCHA, the reactions between THQ5, DHQ, THQ1 and quinoline are so fast that a quasi equilibrium between the four compounds is established quickly at a very low space time. The addition of H2S promotes the reaction of DHQ, but retards the pathway of OPA. The promoting effect of H2S is dominant at low concentration of H2S. However, its inhibiting effect prevails at high concentrations. The HDN via the pathway of DHQ is much easier than OPA over the sulfided NiW/γ‐Al2O3. The HDN of OPA was suppressed by the presence of Q, THQ1, THQ5, and DHQ, maybe due to their stronger adsorption on the catalyst. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Semi‐industrial tests on enhanced underground coal gasification at Zhong‐Liang‐Shan coal mine
Authors: Wang G. X. , Wang Z. T. , Feng B. , Rudolph V. , Jiao J. L.
Published: July 2009

A new process of enhanced underground coal gasification (EUCG) has been demonstrated recently in successful semi‐industrial tests at Zhong‐Liang‐Shan (ZLS) coal mine in China. The EUCG is featured using man‐built pinnate channels and controlled moving injection points along coal‐bed channel to produce syngas through underground coal gasification (UCG). To optimize the EUCG process, this field trial was performed with various operational manoeuvres, such as implementing controlled moving injection points, O2‐enriched operation and variation of operational pressure. The results showed that these operational techniques of the EUCG can ensure the gas flow comparatively controllable and hence improve UCG performance significantly, providing both a higher efficiency of heat and a higher quality of the production syngas. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Development of thin film composite for CO2 separation in membrane gas absorption application
Authors: Ahmad A.L. , Sunarti A.R. , Teong L.K. , Fernando W.J.N.
Published: July 2009

The thin film composite (TFC) membrane based on polypropylene (PP) and polyvinylidenefluoride (PVDF) was prepared using glutaraldehyde as the selective layer. The percentages of glutaraldehyde were optimized to maximize the permeability of carbon dioxide (CO2) and selectivity as well. The TFC with 6% w/v of glutaraldehyde based on PVDF achieved the highest permeance of 881.70 GPU and 18.08 for selectivity through the increase in effective layer and skin layer thickness. This TFC promises to provide porous and hydrophobic membranes for use in membrane gas absorption (MGA) processes. The absorption of CO2 in deionized water was studied in MGA system in which the mass transfer coefficient (K) and CO2 flux decreased with increasing CO2 concentration in feed stream. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Supercritical CO2 induced phase transition of Form III in isotactic poly‐1‐butene
Authors: Li Lei , Liu Tao , Zhao Ling , Yuan Wei‐kang
Published: July 2009

The effect of supercritical or high‐pressure CO2 on the recrystallization of Form II in isotactic poly‐1‐butene (iPB‐1) during the melting of Form III was investigated using high‐pressure differential scanning calorimetry (DSC). The results showed that the recrystallization of Form II was inhibited by CO2. The crystal–crystal transition of Form III to I′ in ambient nitrogen and supercritical CO2 was studied using fourier transform infrared spectroscopy (FTIR) and DSC. The results showed that CO2 promoted the phase transition and the transition proportion of Form III increased with the CO2 pressure increasing. Form III completely transformed into Form I′ at 18 MPa. Moreover, supercritical CO2 could induce the amorphous region to transit into Form I′. The probable mechanism of the CO2 effects on Form III multiple transitions was also proposed. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Vapor‐phase elemental mercury adsorption by Ca(OH)2 impregnated with MnO2 and Ag in fixed‐bed system
Authors: Wang Y. J. , Duan Y. F. , Huang Z. J. , Meng S. L. , Yang L. G. , Zhao C. S.
Published: July 2009

The ability of three sorbents (untreated Ca(OH)2, MnO2‐impregnated Ca(OH)2 and Ag‐impregnated Ca(OH)2) removing the elemental mercury had been studied using a laboratory‐scale fixed‐bed reactor at 80 °C under simulated fuel gas conditions. The adsorption performance of the three sorbents was compared by mercury removal efficiency and adsorption capacity. The effect of acid gases such as HCl and SO2 on the mercury removal was investigated and presented in this article. The results showed that the mercury removal by Ca(OH)2 was mainly controlled by physical mechanisms. In the case of Ca(OH)2, the presence of both SO2 and HCl promoted the Hg0 removal, and compared HCl with SO2, HCl had a higher mercury removal than SO2. Ca(OH)2 impregnated with MnO2 had a slightly higher mercury removal than the original Ca(OH)2, but it was beneficial for mercury speciation. The presence of both SO2 and HCl promotes the Hg0 removal greatly, which was adsorbed by Ca(OH)2 impregnated with MnO2. The Ca(OH)2 impregnated with MnO2 adsorbed more than 50% total Hg due to the occurrence of chemisorptions. The mercury removal by Ca(OH)2 impregnated with Ag was the highest. The reason might be that mercury integrated with silver easily that could produce silver amalgam alloy. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
In situ measurement of erythromycin crystal size distribution by focused beam reflective measurement technology
Authors: Chen Kui , Cao Bing , Zhu Jiawen , Wu Bin , Ji Lijun
Published: July 2009

Many factors such as temperature, solvent and water‐dosing rate have impact on erythromycin solventing‐out process. This article studies the water dosing effect on erythromycin solventing‐out process measured by focused beam reflective measurement technology. Our experiments showed that the overall number of nucleated particles went through an explosive increasing after the metastable zone. Followed by a slight decreasing, it reached a relative constancy for a long time. This suggests that earlier crystal nucleation can be induced with higher water dosing rate, nevertheless, it is the same amount of water dosed when the overall crystal number reached its peak during the explosive emergence of crystals. After the overall particle number climaxed, further extension of crystal growth time would not bring any significant increase in crystal size. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Integrated strategies for assessment of metabolite exposure in humans during drug development: analytical challenges and clinical development considerations
Authors: Zhu Mingshe , Zhang Donglu , Zhang Haiying , Shyu Wen Chyi
Published: July 2009

Monitoring the exposure of a drug and its metabolites in humans and preclinical species during drug development is required to ensure that the safety of drug‐related components in humans are adequately assessed in the standard toxicology studies. Recently published FDA guidance on metabolites in safety testing (MIST) has generated broad discussion from various perspectives. Most of the opinions and experiences shared among the scientific community are scientifically sound and practical. There are various approaches to assess the metabolite exposure margin between toxicology species and humans: either by direct or indirect comparison or by qualitative or quantitative comparison. The choice of when and how to pursuit metabolite assessment is based on the overall development strategy of the compound. Therefore, it is important to understand the utility and limitations of analytical instruments in order to apply an appropriate analytical tool to address specific questions posed at different stages of drug development. The urgency of metabolite monitoring depends on the intrinsic nature of the compound, therapeutic intent and objective of the clinical development. The strategy for assessing metabolite exposure in humans should be a holistic approach considering clinical situations and cumulative knowledge of the metabolism of the drug in order to appropriately address metabolite safety in humans. A one‐size‐fits‐all approach is rarely the best use of resources. Copyright © 2009 John Wiley & Sons, Ltd.
Metabolites in safety testing: metabolite identification strategies in discovery and development
Authors: Nedderman Angus N. R.
Published: July 2009

The publication of the FDA MIST guidelines in 2008, together with the acknowledged importance of metabolism data for the progression of novel compounds through drug discovery and drug development, has resulted in a renewed focus on the metabolite identification strategies utilised throughout the pharmaceutical industry. With the plethora of existing and emerging technologies available to the metabolite identification scientist, it is argued that increased diligence should be applied to metabolism studies in the early stages of both drug discovery and drug development, in order to more routinely impact chemical design and to comply with the concepts of the MIST guidance without re‐positioning the definitive radiolabelled studies from there typical place in late development.

Furthermore, these strategic elements should be augmented by a broad and thorough understanding of the impact of the derived metabolism data, most notably considerations of absolute abundance, structure and pharmacological activity, such that they can be put into proper context as part of a holistic safety strategy.

The combination of these approaches should ensure a metabolite identification strategy that successfully applies the principles of the MIST guidance throughout the discovery/development continuum and thereby provides appropriate confidence in support of human safety. Copyright © 2009 John Wiley & Sons, Ltd.
Reproductive toxicity and pharmacokinetics of di‐n‐butyl phthalate (DBP) following dietary exposure of pregnant rats
Authors: Struve Melanie F. , Gaido Kevin W. , Hensley Janan B. , Lehmann Kim P. , Ross Susan M. , Sochaski Mark A. , Willson Gabrielle A. , Dorman David C.
Published: July 2009

Most rodent developmental toxicity studies of dibutylphthalate (DBP) have relied on bolus gavage dosing. This study characterized the developmental toxicity of dietary DBP. Pregnant CD rats were given nominal doses of 0, 100, or 500 mg DBP/kg/day in diet (actual intake 0, 112, and 582 mg/kg/day) from gestational day (GD) 12 through the morning of GD 19. Rats were killed 4 or 24 hr thereafter. DBP dietary exposure resulted in significant dose‐dependent reductions in testicular mRNA concentration of scavenger receptor class B, member 1; steroidogenic acute regulatory protein; cytochrome P450, family 11, subfamily a, polypeptide 1; and cytochrome P450 family 17, subfamily a, polypeptide 1. These effects were most pronounced 4 hr after the end of exposure. Testicular testosterone was reduced 24 hr post‐exposure in both DBP dose groups and 4 hr after termination of the 500‐mg DBP/kg/day exposure. Maternal exposure to 500 mg DBP/kg/day induced a significant reduction in male offspring's anogenital distance indicating in utero disruption of androgen function. Leydig cell aggregates, increased cord diameters, and multinucleated gonocytes were present in DBP‐treated rats. Monobutyl phthalate, the developmentally toxic metabolite of DBP, and its glucuronide conjugate were found in maternal and fetal plasma, amniotic fluid, and maternal urine. Our results, when compared to previously conducted gavage studies, indicate that approximately equal doses of oral DBP exposure of pregnant rats, from diet or gavage, result in similar responses in male offspring.Birth Defects Res (Part B), 86:345–354, 2009. © 2009 Wiley‐Liss, Inc.
New luminol chemiluminescence reaction using diperiodatoargentate as oxidate for the determination of amikacin sulfate
Authors: Yang Chunyan , Zhang Zhujun , Wang Jinli
Published: July 2009

A new chemiluminescence (CL) reaction between luminol and diperiodatoargentate {K2 [Ag (H2IO6) (OH) 2]} was observed in alkaline medium. The CL intensity could be greatly enhanced by amikacin sulfate. Therefore a new CL method for the determination of amikacin sulfate was built by combining with flow injection technology. A possible mechanism of the CL reaction was proposed via the investigation of the CL kinetic characteristics, the CL spectrum and the UV absorption spectra of some related substance. The concentration range of linear response was 5.1 × 10−8 to 5.1 × 10−6 mol L−1 with a detection limit of 1.9 × 10−8 mol L−1 (3σ). The proposed method had good reproducibility with a relative standard deviation of 2.8% (n = 7) for 5.1 × 10−7 mol L−1 of amikacin sulfate. It was successfully applied to determine amikacin sulfate in serum. Copyright © 2009 John Wiley & Sons, Ltd.
Factors influencing antibody stability at solid–liquid interfaces in a high shear environment
Authors: Biddlecombe James G. , Smith Graeme , Uddin Shahid , Mulot Sandrine , Spencer David , Gee Chris , Fish Brendan C. , Bracewell Daniel G.
Published: July 2009

A rotating disk shear device was used to study the effect of interfacial shear on the structural integrity of human monoclonal antibodies of IgG4 isotype. Factors associated with the solution conditions (pH, ionic strength, surfactant concentration, temperature) and the interface (surface roughness) were studied for their effect on the rate of IgG4 monomer loss under high shear conditions. The structural integrity of the IgG4 was probed after exposure to interfacial shear effects by SDS‐PAGE, IEF, dynamic light scattering, and peptide mapping by LC‐MS. This analysis revealed that the main denaturation pathway of IgG4 exposed to these effects was the formation of large insoluble aggregates. Soluble aggregation, breakdown in primary structure, and chemical modifications were not detected. The dominant factors found to affect the rate of IgG4 monomer loss under interfacial shear conditions were found to be pH and the nanometer‐scale surface roughness associated with the solid‐liquid interface. Interestingly, temperature was not found to be a significant factor in the range tested (15–45°C). The addition of surfactant was found to have a significant stabilizing effect at concentrations up to 0.02% (w/v). Implications of these findings for the bioprocessing of this class of therapeutic protein are briefly discussed. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
Determination of the lactate threshold and maximal blood lactate steady state intensity in aged rats
Authors: Cunha Rafael Rodrigues , de Carvalho Cunha Verusca Najara , Segundo Paulo Russo , Moreira Sérgio Rodrigues , Kokubun Eduardo , Campbell Carmen Sílvia Grubert , Jacó de Oliveira Ricardo , Simões Herbert Gustavo
Published: July 2009

The reliability of the lactate threshold (LT) determined in aged rats and its validity to identify an exercise intensity corresponding to the maximal blood lactate steady state (MLSS) were analyzed. Eighteen male aged Wistar rats (∼365 days) were submitted to two incremental swimming tests until exhaustion, consisting of an initial load corresponding to 1% of body mass (BM) and increments of 1% BM at each 3‐min with blood lactate ([lac]) measurements. The LT was determined by visual inspection (LTV) as well by applying a polynomial function on the [lac]/workload ratio (LTP) by considering the vertices of the curve. For the MLSS, twelve animals were submitted, on different days, to 3–4 exercise sessions of 30‐min with workload corresponding to 4, 5 or 6% BM. The MLSS was considered the highest exercise intensity at which the [lac] variation was not higher than 0.07 mM.min−1 during the last 20‐min. No differences were observed for the test‐retest results (4.9 ± 0.7 and 5.0 ± 0.8 %BM for LTv; and 6.0 ± 0.6 and 5.8 ± 0.6 %BM for LTp) that did not differ from the MLSS (5.4 ± 0.5 %BM). The LT identified for aged rats in swimming, both by visual inspection and polynomial function, was reliable and did not differ from the MLSS. Copyright © 2009 John Wiley & Sons, Ltd.