bluuebunny/crossref_metadata_2025 huggingface dataset:
Reduced negative surface charge on arterial endothelium explains accelerated atherosclerosis in type 2 diabetic patients
Authors: Nassimizadeh Mohammad , Ashrafian Houman , Drury Nigel E , Howell Neil J , Digby Janet , Pagano Domenico , Frenneaux Michael P , Born Gustav VR
Published: July 2010

Reduced endothelial surface charge markedly increases the rate of LDL uptake into blood vessels. Previous work in the streptozotocin diabetic rat reported reduced endothelial surface charge. We compared endothelial surface charge density in internal mammary artery rings from patients with type 2 diabetes (n = 12) and from non diabetic patients undergoing coronary artery bypass grafting, and observed a substantial (52%) reduction in the former. This was associated with higher plasma sialic acid levels suggesting loss of sialic acid residues from the glycocalyx as a possible mechanism.
Single-nucleotide polymorphism, linkage disequilibrium and geographic structure in the malaria parasite Plasmodium vivax: prospects for genome-wide association studies
Authors: Orjuela-Sánchez Pamela , Karunaweera Nadira D , da Silva-Nunes Mônica , da Silva Natal S , Scopel Kézia KG , Gonçalves Raquel M , Amaratunga Chanaki , Sá Juliana M , Socheat Duong , Fairhust Rick M , Gunawardena Sharmini , Thavakodirasah Thuraisamy , Galapaththy Gawrie LN , Abeysinghe Rabindra , Kawamoto Fumihiko , Wirth Dyann F , Ferreira Marcelo U
Published: July 2010

Background

The ideal malaria parasite populations for initial mapping of genomic regions contributing to phenotypes such as drug resistance and virulence, through genome-wide association studies, are those with high genetic diversity, allowing for numerous informative markers, and rare meiotic recombination, allowing for strong linkage disequilibrium (LD) between markers and phenotype-determining loci. However, levels of genetic diversity and LD in field populations of the major human malaria parasite P. vivax remain little characterized.

Results

We examined single-nucleotide polymorphisms (SNPs) and LD patterns across a 100-kb chromosome segment of P. vivax in 238 field isolates from areas of low to moderate malaria endemicity in South America and Asia, where LD tends to be more extensive than in holoendemic populations, and in two monkey-adapted strains (Salvador-I, from El Salvador, and Belem, from Brazil). We found varying levels of SNP diversity and LD across populations, with the highest diversity and strongest LD in the area of lowest malaria transmission. We found several clusters of contiguous markers with rare meiotic recombination and characterized a relatively conserved haplotype structure among populations, suggesting the existence of recombination hotspots in the genome region analyzed. Both silent and nonsynonymous SNPs revealed substantial between-population differentiation, which accounted for ~40% of the overall genetic diversity observed. Although parasites clustered according to their continental origin, we found evidence for substructure within the Brazilian population of P. vivax. We also explored between-population differentiation patterns revealed by loci putatively affected by natural selection and found marked geographic variation in frequencies of nucleotide substitutions at the pvmdr-1 locus, putatively associated with drug resistance.

Conclusion

These findings support the feasibility of genome-wide association studies in carefully selected populations of P. vivax, using relatively low densities of markers, but underscore the risk of false positives caused by population structure at both local and regional levels.

See commentary: http://www.biomedcentral.com/1741-7007/8/90
Association of childhood trauma with cognitive function in healthy adults: a pilot study
Authors: Majer Matthias , Nater Urs M , Lin Jin-Mann S , Capuron Lucile , Reeves William C
Published: July 2010

Background

Animal and human studies suggest that stress experienced early in life has detrimental consequences on brain development, including brain regions involved in cognitive function. Cognitive changes are cardinal features of depression and posttraumatic stress disorder. Early-life trauma is a major risk factor for these disorders. Only few studies have measured the long-term consequences of childhood trauma on cognitive function in healthy adults.

Methods

In this pilot study, we investigated the relationship between childhood trauma exposure and cognitive function in 47 healthy adults, who were identified as part of a larger study from the general population in Wichita, KS. We used the Cambridge Neuropsychological Test Automated Battery (CANTAB) and the Wide-Range-Achievement-Test (WRAT-3) to examine cognitive function and individual achievement. Type and severity of childhood trauma was assessed by the Childhood Trauma Questionnaire (CTQ). Data were analyzed using multiple linear regression on CANTAB measures with primary predictors (CTQ scales) and potential confounders (age, sex, education, income).

Results

Specific CTQ scales were significantly associated with measures of cognitive function. Emotional abuse was associated with impaired spatial working memory performance. Physical neglect correlated with impaired spatial working memory and pattern recognition memory. Sexual abuse and physical neglect were negatively associated with WRAT-3 scores. However, the association did not reach the significance level of p < 0.01.

Conclusions

Our results suggest that physical neglect and emotional abuse might be associated with memory deficits in adulthood, which in turn might pose a risk factor for the development of psychopathology.
Dissemination of multidrug resistant Acinetobacter baumannii in various hospitals of Antananarivo Madagascar
Authors: Andriamanantena Tahiry S , Ratsima Elisoa , Rakotonirina Hanitra C , Randrianirina Frédérique , Ramparany Lovasoa , Carod Jean-François , Richard Vincent , Talarmin Antoine
Published: July 2010

This study reports the dissemination of multidrug-resistant (MDR) OXA-23-producingAcinetobacter baumanniiclones in hospitals in Antananarivo, Madagascar. A total of 53 carbapenem-resistantA. baumanniiisolates were obtained from September 2006 to March 2009 in five hospitals. These resistant strains represent 44% of allA. baumanniiisolates. The double disk synergy test was performed to screen for production of metallo-beta-lactamases. Polymerase chain reaction (PCR) and DNA sequencing were performed for the detection ofbla(AmpC), bla(OXA-51),bla(OXA-23), bla(OXA-24), bla(IMP),bla(VIM). The presence of the insertion sequence ISAba1relative toblaOXA-23 andblaOXA-51 was assessed by PCR. Isolates were typed by Rep-PCR. All the isolates were MDR and produced the OXA-23 carbapenemase, which was confirmed by sequencing. PCR analysis for AmpC and OXA-51 gave positive results for all strains studied. No isolates produced metallo-beta-lactamases. In all isolates ISAba1laid upstream ofblaOXA-23. TheA. baumanniiisolates were separated into two genotypes; genotype A had a higher prevalence (41 strains) than genotype B (12 strains). Genotype A was present in four hospitals, whilst genotype B had spread in two hospitals. The high frequency of MDR OXA-23-producingA. baumanniiin various hospitals in Antananarivo is curious since carbapenems are not available in Madagascar, but it emphasises the need for infection control procedures and strict adherence to them to prevent the spread of these resistant organisms in Antananarivo and also the need to control the use of carbapenems in the future.
Ezetimibe/simvastatin vs simvastatin in coronary heart disease patients with or without diabetes
Authors: Rotella Carlo M , Zaninelli Augusto , Le Grazie Cristina , Hanson Mary E , Gensini Gian Franco
Published: July 2010

Background

Treatment guidelines recommend LDL-C as the primary target of therapy in patients with hypercholesterolemia. Moreover, combination therapies with lipid-lowering drugs that have different mechanisms of action are recommended when it is not possible to attain LDL-C targets with statin monotherapy. Understanding which treatment or patient-related factors are associated with attaining a target may be clinically relevant.

Methods

Data were pooled from two multicenter, randomized, double-blind studies. After stabilization on simvastatin 20 mg, patients with coronary heart disease (CHD) alone and/or type 2 diabetes mellitus (T2DM) were randomized to ezetimibe 10 mg/simvastatin 20 mg (EZ/Simva) or simvastatin 40 mg. The change from baseline in low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), TC/HDL-C ratio, triglycerides, and the proportion of patients achieving LDL-C < 2.6 mmol/L (100 mg/dL) after 6 weeks of treatment were assessed, and factors significantly correlated with the probability of achieving LDL-C < 2.6 mmol/L in a population of high cardiovascular risk Italian patients were identified. A stepwise logistic regression model was conducted with LDL-C < 2.6 mmol/L at endpoint as the dependent variable and study, treatment, gender, age (≥65 years or < 65 years), as independent variables and baseline LDL-C (both as continuous and discrete variable).

Results

EZ/Simva treatment (N = 93) resulted in significantly greater reductions in LDL-C, TC, and TC/HDL-C ratio and higher attainment of LDL-C < 2.6 mmol/L vs doubling the simvastatin dose to 40 mg (N = 106). Study [including diabetic patients (OR = 2.9, p = 0.003)], EZ/Simva treatment (OR = 6.1, p < 0.001), and lower baseline LDL-C (OR = 0.9, p = 0.001) were significant positive predictors of LDL-C target achievement. When baseline LDL-C was expressed as a discrete variable, the odds of achieving LDL-C < 2.6 mmol/L was 4.8 in favor of EZ/Simva compared with Simva 40 mg (p < 0.001), regardless of baseline LDL-C level.

Conclusion

EZ/Simva is an effective therapeutic option for patients who have not achieved recommended LDL-C treatment targets with simvastatin 20 mg monotherapy.

Trial Registration

Clinical trial registration numbers: NCT00423488 and NCT00423579
Chemoimmunotherapy With a Modified Hyper-CVAD and Rituximab Regimen Improves Outcome in De Novo Philadelphia Chromosome–Negative Precursor B-Lineage Acute Lymphoblastic Leukemia
Authors: Thomas Deborah A. , O'Brien Susan , Faderl Stefan , Garcia-Manero Guillermo , Ferrajoli Alessandra , Wierda William , Ravandi Farhad , Verstovsek Srdan , Jorgensen Jeffrey L. , Bueso-Ramos Carlos , Andreeff Michael , Pierce Sherry , Garris Rebecca , Keating Michael J. , Cortes Jorge , Kantarjian Hagop M.
Published: July 2010

Purpose

The adverse prognosis of CD20 expression in adults with de novo precursor B-lineage acute lymphoblastic leukemia (ALL) prompted incorporation of monoclonal antibody therapy with rituximab into the intensive chemotherapy regimen hyper-CVAD (fractionated cyclophosphamide, vincristine, doxorubicin, dexamethasone). Other modifications (irrespective of CD20 expression) included early anthracycline intensification, alterations in number of risk-adapted intrathecal chemotherapy treatments for CNS prophylaxis, additional early and late intensifications, and extension of maintenance phase chemotherapy by 6 months.

Patients and Methods

Two hundred eighty-two adolescents and adults with de novo Philadelphia chromosome (Ph)–negative precursor B-lineage ALL were treated with standard or modified hyper-CVAD regimens. The latter incorporated standard-dose rituximab if CD20 expression ≥ 20%.

Results

The complete remission (CR) rate was 95% with 3-year rates of CR duration (CRD) and survival (OS) of 60% and 50%, respectively. In the younger (age < 60 years) CD20-positive subset, rates of CRD and OS were superior with the modified hyper-CVAD and rituximab regimens compared with standard hyper-CVAD (70% v 38%; P < .001% and 75% v 47%, P = .003). In contrast, rates of CRD and OS for CD20-negative counterparts treated with modified versus standard hyper-CVAD regimens were similar (72% v 68%, P = not significant [NS] and 64% v 65%, P = NS, respectively). Older patients with CD20-positive ALL did not benefit from rituximab-based chemoimmunotherapy (rates of CRD 45% v 50%, P = NS and OS 28% v 32%, P = NS, respectively), related in part to deaths in CR.

Conclusion

The incorporation of rituximab into the hyper-CVAD regimen appears to improve outcome for younger patients with CD20-positive Ph-negative precursor B-lineage ALL.
The function of TONNEAU1 in moss reveals ancient mechanisms of division plane specification and cell elongation in land plants
Authors: Spinner Lara , Pastuglia Martine , Belcram Katia , Pegoraro Mathieu , Goussot Magali , Bouchez David , Schaefer Didier G.
Published: July 2010

The preprophase band (PPB) is a transient ring of microtubules that forms before mitosis in land plants, and delineates the cytokinetic division plane established at telophase. It is one of the few derived traits specific to embryophytes, in which it is involved in the spatial control of cell division. Here we show that loss of function of Physcomitrella patens PpTON1 strongly affects development of the moss gametophore, phenocopying the developmental syndrome observed in Arabidopsis ton1 mutants: mutant leafy shoots display random orientation of cell division and severe defects in cell elongation, which are correlated with absence of PPB formation and disorganization of the cortical microtubule array in interphase cells. In hypomorphic Ppton1 alleles, PPB are still formed, whereas elongation defects are observed, showing the dual function of TON1 in organizing cortical arrays of microtubules during both interphase and premitosis. Ppton1 mutation has no impact on development of the protonema, which is consistent with the documented absence of PPB formation at this stage, apart from alteration of the gravitropic response, uncovering a new function of TON1 proteins in plants. Successful reciprocal cross-complementation between Physcomitrella and Arabidopsis shows conservation of TON1 function during land plant evolution. These results establish the essential role of the PPB in division plane specification in a basal land plant lineage, and provide new information on the function of TON1. They point to an ancient mechanism of cytoskeletal control of division plane positioning and cell elongation in land plants.
Developing social capital: a role for music education and community music in fostering civic engagement and intercultural understanding
Authors: Jones Patrick M
Published: July 2010

This article posits that musicking can uniquely foster the development of social capital, which leads to civic engagement and intercultural understanding. I review pertinent literature and build a case that music educators and community musicians have a unique role to play in its development.
I also reveal a weakness in the theoretical framework of social capital and in the music research literature, and I advocate for developing a richer theoretical framework that analyses both the development of social capital and the unique civic roles, social skills, habits and dispositions
developed in various musical practices.
Identification and evaluation of a new nucleic acid amplification test target for specific detection of Mycobacterium tuberculosis
Authors: Qin Lianhua , Zheng Ruijuan , Fan Chao , Cai Jiangli , Liu Zhonghua , Wang Jie , Lu Junmei , Jin Ruiliang , Yang Hua , Cui Zhenling , Feng Yonghong , Hu Zhongyi
Published: July 2010

Background: Accurate and early diagnosis of tuberculosis (TB) is of major importance in the management and control of TB. Because the conventional bacteriological diagnosis of TB has several limitations, nucleic acid amplification (NAA) tests have emerged as promising alternatives. A potential problem with NAA tests is that some strains lack a target, which may be the one of main reasons for the much lower and highly variable accuracy in diagnosis. A possible solution may be to use more valid and applicable targets to increase detection accuracy.

Methods: In this paper, we designed a two-step program to obtain NAA test targets. Inter-simple sequence repeats (ISSR) based on oligonucleotide (GTG)5 were first constructed to genotype Mycobacterium strains to obtain Mycobacterium tuberculosis (MTB)-specific fragment. Second, sequence characterized amplified region (SCAR) markers were developed from these species-specific sequences to identify MTB. Some 312 Mycobacterium strains were used to evaluate the efficacy of the SCAR markers, IS6110 element [specific identification of Mycobacterium tuberculosis complex (MTC)] and 16SrRNA gene (specific identification of Mycobacterium) amplification, together with traditional bacteriology testing was used as a control.

Results: MTB-specific sequences located in a gene coding for Rv1508c, as a new NAA test target, were obtained using ISSR-PCR genotyping. Based on these sequences, the SCAR primer pairs MISP1 and MISP2 were designed. All 312 strains from Mycobacterium accurately produced the genus-specific 16SrRNA amplicon. 271 MTB strains and M. africanum were positive. However, all nontuberculous mycobacteria (NTM) strains and 1 MTB strain named 1143 were negative in both SCAR and IS6110 PCR amplification. M. bovis, bacille Calmette-Guérin (BCG) were IS6110-PCR positive, while SCAR-PCR was negative. Strain 1143 was defined as M. arupense with 99% identity by 16SrRNA gene sequencing identification, despite being diagnosed as MTB using traditional testing.

Conclusions: SCAR markers developed with this two-step program can be used as a new NAA test target to correctly detect MTB.

Clin Chem Lab Med 2010;48:1501–5.
Targeting DNA Double-Strand Breaks with TAL Effector Nucleases
Authors: Christian Michelle , Cermak Tomas , Doyle Erin L , Schmidt Clarice , Zhang Feng , Hummel Aaron , Bogdanove Adam J , Voytas Daniel F
Published: July 2010

Engineered nucleases that cleave specific DNA sequences in vivo are valuable reagents for targeted mutagenesis. Here we report a new class of sequence-specific nucleases created by fusing transcription activator-like effectors (TALEs) to the catalytic domain of the FokI endonuclease. Both native and custom TALE-nuclease fusions direct DNA double-strand breaks to specific, targeted sites.
Noninvasive Continuous Positive Airway Pressure in Acute Respiratory Failure: Helmet Versus Facial Mask
Authors: Chidini Giovanna , Calderini Edoardo , Cesana Bruno Mario , Gandini Cristiano , Prandi Edi , Pelosi Paolo
Published: July 2010

OBJECTIVE:

Noninvasive continuous positive airway pressure (nCPAP) is applied through different interfaces to treat mild acute respiratory failure (ARF) in infants. Recently a new pediatric helmet was introduced in clinical practice to deliver nCPAP. The objective of this study was to compare the feasibility of the delivery of nCPAP by the pediatric helmet with delivery by a conventional facial mask in infants with ARF.

PATIENTS AND METHODS:

We conducted a single-center physiologic, randomized, controlled study with a crossover design on 20 consecutive infants with ARF. All patients received nCPAP by helmet and facial mask in random order for 90 minutes. In infants in both trials, nCPAP treatment was preceded by periods of unassisted spontaneous breathing through a Venturi mask. The primary end point was the feasibility of nCPAP administered with the 2 interfaces (helmet and facial mask). Feasibility was evaluated by the number of trial failures defined as the occurrence of 1 of the following: intolerance to the interface; persistent air leak; gas-exchange derangement; or major adverse events. nCPAP application time, number of patients who required sedation, and the type of complications with each interface were also recorded. The secondary end point was gas-exchange improvement.

RESULTS:

Feasibility of nCPAP delivery was enhanced by the helmet compared with the mask, as indicated by a lower number of trial failures (P < .001), less patient intolerance (P < .001), longer application time (P < .001), and reduced need for patient sedation (P < .001). For both delivery methods, no major patient complications occurred.

CONCLUSIONS:

The results of this current study revealed that the helmet is a feasible alternative to the facial mask for delivery of nCPAP to infants with mild ARF.
Stem cells in prostate cancer: treating the root of the problem
Authors: Taylor Renea A , Toivanen Roxanne , Risbridger Gail P
Published: July 2010

Prostate cancer is a hormone-dependent, epithelial-derived tumor, resulting from uncontrolled growth of genetically unstable transformed cells. Stem cells are therapeutic targets for prostate cancer, but as disease progression occurs over decades, the imperative is to identify and target the cancer-repopulating cell (CRC) that maintains malignant clones. In order to achieve this goal, we will review the current knowledge of three specific types of cells, their origins, and their differentiation potential. The first is the normal stem cell, the second is the cancer cell of origin, and the third is the CRC. Specifically, we review three proposed models of stem cell differentiation in normal tissues, including linear, bidirectional, and independent lineages. We consider evidence of the cancer cell of origin arising from both basal and luminal cells. Finally, we discuss the limited data available on the identity and characterization of CRCs in localized and castrate-resistant prostate cancer, which is where we believe the focus of future research efforts should be directed. Ultimately, understanding the intrinsic or extrinsic influences that dictate the behavior of these unique cells will be instrumental in facilitating the development of new therapeutic targets for prostate cancer.
Hypothalamic regulation of bone
Authors: Driessler Frank , Baldock Paul A
Published: July 2010

On initial inspection, bone remodeling, the process whereby the skeleton adapts through time, appears to be relatively simple. Two cell types, the bone-forming osteoblasts and the bone-resorbing osteoclasts, interact to keep bone mass relatively stable throughout adult life. However, the complexity of the regulatory influences on these cells is continuing to expand our understanding of the intricacy of skeletal physiology and also the interactions between other organ systems and bone. One such example of the broadening of understanding in this field has occurred in the last decade with study of the central, neural regulation of bone mass. Initial studies of an adipose-derived hormone, leptin, helped define a direct, sympathetic pathway involving efferent neural signals from the hypothalamus to receptors on the osteoblast. Since the leptin-mediated pathway has been continuously modified to reveal a complex system involving neuromedin U, cocaine- and amphetamine-related transcript and serotonin interacting within the hypothalamus and brainstem to regulate both bone formation and resorption in cancellous bone, a number of other systems have also been identified. Neuropeptide Y, acting through hypothalamic Y2 receptors, is capable of skeleton-wide modulation of osteoblast activity, with important coordination between body weight and bone mass. Cannabinoids, acting through central cannabinoid receptor 1 and bone cell cannabinoid receptor 2 receptors, modulate osteoclast activity, thereby identifying pathways active on both aspects of the bone remodeling process. This review explores the key central pathways to bone and explores the complexity of the interactions being revealed by this emergent field of research.
The Influence of Clay Minerals on the Enzymatic Hydrolysis of Organic Phosphorus Compounds
Authors: Mortland Max M. , Gieseking J. E.
Published: July 2010

Organic phosphorus compounds contain a large portion of the total phosphorus in many soils. The release of phosphate from the organic form is thought to be enzymatic in nature. Since clays compose an active and important part of the soil, a study was made of their effect on the enzymatic hydrolysis of several organic phosphorus compounds.

The effect of clays on the enzymatic hydrolysis of fructose‐diphosphate, phytin, glycerophosphate, and lecithin was studied. The enzymes were prepared from bread yeast, wheat bran, bread yeast, and kidney cortex, respectively. The various clays studied included kaolinite, Wyoming bentonite (montmorillonite), Swygert (illite), and Cisne (a clay similar to Putnam). The activity of the enzyme was determined with no clay present, and then in the presence of various amounts and kinds of clays. The enzymatic reactions were performed paying special attention to the control of pH, temperatures, inhibitors, activators, and concentrations. The difference between the activity of the enzyme on the organic phosphorus compound in the presence of a suitable buffer and the activity in the presence of clays was considered a measure of the influence of the clay upon the enzyme activity. All of the clays used in this study exhibited an inhibiting influence upon the enzymatic hydrolysis of the organic phosphorus compounds. The amount of inhibition varied with the kind of clay according to the following series: Wyoming bentonite (montmorillonite) > Cisne (Putnam‐like clay) > Swygert (illite) > kaolinite.

The inhibition of phosphatase activity by clays is roughly proportional to the base exchange capacity of the clay. A constant, evaluated for each clay in an empirical equation which describes hydrolysis of the organic compound in the presence of varying quantities of clay, is approximately equal to the ratios of the base exchange capacities of the various clays. The study indicates that the inhibition is due to the effect of the clay on the enzyme and not to adsorption of the organic phosphorus compound by the clay.
The Titanium Content of Hawaiian Soils and Its Significance
Authors: Sherman G. Donald
Published: July 2010

A study has been made to determine the titanium oxide content of typical soils of each great soil group occurring in the Hawaiian Islands. The nature of the occurrence of titanium oxide and its relationship to soil formation was investigated.

The titanium oxide content of Hawaiian soils ranged from 2.5 to 25.0%. The titanium oxide content is higher in the surface horizon in the soils which are developed under a climate having an alternating wet and dry season. The greatest accumulation was found in the soils belonging to the Humic Ferruginous Latosols, which occur in areas having an alternating wet and dry season but adjacent to the tropical rain forest. Titanium oxide accumulates in tropical soils under the same conditions that iron oxide accumulates. It is easily dehydrated at or near the surface to form concretions, coatings to surfaces of aggregates or soil particles, or as a massive horizon. Titanium oxide, as anatase, rehydrates slower than iron oxide and is more resistant to reduction when the soil internal drainage becomes poorer. Under extreme reducing conditions titanium oxide will be reduced and will be leached from the soil. Under certain conditions of poor drainage the iron and titanium oxides are reduced and removed by leaching, and the aluminum oxide, gibbsite, is resilicated to kaolinite.
Structure and Its Influence on Tilth of Soils
Authors: Klingebiel A. A. , O'Neal A. M.
Published: July 2010

The purpose of this study was to determine some of the changes that have taken place in the structure of several Corn Belt soils and its influence on tilth, permeability, volume weight, and percent of pores drained.

Samples of soil were examined in the field to determine the type, class, and grade of structure, direction of natural fracture when lumps were broken, and size and number of visible pores. Six to twelve undisturbed soil core samples 3 inches thick and 3 inches in diameter were taken at random from each plot and depth to determine permeability, volume weight, and percent of pores drained at 60 centimeters tension.

Many surface soils that originally were granular or crumb in structure have changed through cultivation and poor management practices to a fine fragmental or massive structure. With these changes in structure the percolation rate decreased from 8.4 inches to 0.2 of an inch per hour, percent of pores drained was reduced from 9.2 to 3.5, and the volume weight increased from 1.1 to 1.31.

The surface crust was the least permeable layer in the upper 18 inches of the soils studied.
The Morphology and Genesis of the Gray‐Brown Podzolic and Related Soils of Eastern Canada
Authors: Stobbe P. C.
Published: July 2010

The purpose of this investigation was to establish the range in characteristics of the Gray‐brown Podzolic soils of Eastern Canada and to characterize the different kinds of Gray‐brown Podzolic profiles. It was based on a comparative study of the morphological and some chemical characteristics of all the soil series of this group which have been recognized to date in Canada.

The Gray‐brown Podzolic soils in Eastern Canada occur only on calcareous materials, and their maturity of development can be correlated with the length of time they have been subjected to weathering. They have mull‐like, neutral to moderately acid, A1 horizons, comparatively thick but only slightly to moderately unsaturated A2 horizons and B2 horizons which contain more clay and sesquioxides than the other horizons of the profile.

A number of intergrade Gray‐brown Podzolic types, which possess some characteristics of the other groups in the region, have been characterized. The findings suggest that the cycle of profile development on calcareous materials in this region is from Brown Forest to Gray‐brown Podzolic to Brown Podzolic and Podzol soils.
The Measurement of Oxygen Diffusion in the Soil with a Platinum Microelectrode
Authors: Lemon E. R. , Erickson A. E.
Published: July 2010

The current obtained in the electrolysis of an electro‐reducible material, as oxygen, at the surface of a platinum electrode can be used to calculate the rate of diffusion of that material to the surface. Measurements made in the soil, based on this principle, give promise of furnishing a new, simple, rapid, and inexpensive method of determining the rate of oxygen supply to an undisturbed environment similar to that in the liquid film surrounding an actively respiring plant root. The method compared favorably with other methods for measuring soil aeration in a greenhouse experiment.

Evidence presented indicates that factors controlling the diffusion rate in the gaseous phase of the soil extend into the liquid phase as well. The data show greater oxygen diffusion rates with larger aggregates and greater soil porosity. The rates decreased with increasing depth below the soil surface. At the lower porosities moisture film thickness has a greater effect on oxygen supply than at the higher porosities.

Growth of tomatoes correlates well with oxygen diffusion measurements made with the microelectrode, and a critical rate is suggested for their growth.
Factors Affecting the Interlayer Expansion of Vermiculite and Montmorillonite with Organic Substances
Authors: Barshad Isaac
Published: July 2010

An evaluation of the factors affecting interlayer expansion of the mica type layered minerals was made by X‐raying various dehydrated forms of montmorillonite and vermiculite while immersed in liquids of varying dipole moments and dielectric constants. The results showed that the extent of interlayer expansion was determined by the size, charge, and total amount of the interlayer cations and by the magnitude of the dipole moment and the dielectric constant of the immersion liquid. The results were explained on the basis of the nature of the electrostatic interlayer attractive forces within the crystal lattice itself and by the laws governing complex formation between charged particles.
Field Measurements for Tests of Soil Drainage Theory
Authors: Kirkham D. , de Zeeuw J. W.
Published: July 2010

Measurements are reported for water table heights, rainfall, permeability, and in some cases, of ditch and drain tile outflow, for tile drains and ditch drains in replicated plots in the recently reclaimed North East Polder, the Netherlands. The spacing of the ditches and tiles is 8, 10, 12, and 16 meters, the nominal depth of tiles 1 meter, of ditches 60 cm. The measurements were made in November and December 1950, when evaporation and transpiration effects were small, and are believed to be the most extensive measurements yet made for testing modern drainage theory under field conditions. An order of magnitude theoretical test of the data appears satisfactory. From an immediately practical view point it was found that tiles, apparently because of their greater depth, kept the water table lower at all times than the ditches. Tiles at 50‐foot (16‐meter) spacing kept the water table ½ foot below the soils surface; tiles at 25‐foot spacing kept the water table 2 feet below the soil surface. For ditches at the same spacings the values were ¼ foot and 1 foot 3 inches.
A Forest Land Capability Classification
Authors: Plair T. B.
Published: July 2010

The objective of this forest land capability classification is to classify forest land on a basis of permanent physical factors for the purpose of providing an index to the land and crop management requirements and potentials.

It is suggested that all forest soils be grouped into four capability classes. The first class would be the highly productive forest soils, having few or limited hazards to soil losses or damage and only minor limitations to use of equipment or application of any management practice. The fourth class would be the noncommercial forest lands. These would be the extremely high‐hazard lands, or those soils very low in production, or those having conditions requiring excessive operating costs, or a combination of these. The second and third classes would include those lands between the first and the fourth classes.

The specific site indices (the total average height that has been or will be attained at a given age — ordinarily 50 to 100 years) or the slope groups that would be put in any one capability class could be different for each forest region, subregion, or individual making the classification. Standardization can and should be achieved to the extent of defining the capability classes and subclasses. The following graphic presentation is suggested as a standard.

Class A1 — Very well suited to forestry; low hazards, minor limitations and high productive potential.

Class B1 — Well suited to forestry; moderate hazards and limitations with high productive potential.

Class B2 — Well suited to forestry; moderate productive potential with low hazards and minor limitations in use.

Class B3 — Well suited to forestry; moderate productive capacity with moderate hazards and limitations to use.

Class C1 — Fairly well suited to forestry. High hazards, severe limitations, and high productive potential.

Class C2 — Fairly well suited to forestry. High hazards and severe limitations with moderate productive capacity.

Class C3 — Fairly well suited to forestry; low hazards with minor limitations and low productive potential.

Class C4 — Fairly well suited to forestry; moderate hazards and moderate limitations with low productive potential.

Class C5 — Fairly well suited to forestry. High hazards, severe limitations with low productive potential.

Class D — Unsuited to economic productive use for forestry due to excessive hazards and limitations and extremely low productivity.
A Study of the Relationship between Chemically Available Phosphorus and Plant Growth Response on Several Michigan Soils
Authors: Smith F. W. , Cook R. L.
Published: July 2010

The objective of this investigation was to correlate plant growth response with chemically measured available phosphorus in the soil.

Eight chemical methods of extracting the available phosphorus in the soil samples were utilized. An attempt was made to correlate growth response of wheat with chemically measured available phosphorus. The principles of Mitscherlich as modified by Bray were employed.

In general, the amount of chemically measured phosphorus as extracted by the Spurway active extracting solution was quite low in comparison to that extracted by the other methods, all of which contained some hydrochloric acid. Increasing the time of shaking during extraction or increasing the ratio of extracting solution to soil did not improve the Spurway active test.

The use of any of the methods of Bray provided a considerably clearer picture of phosphorus availability because the inclusion of fluoride in the extracting solution enabled the adsorbed phosphorus in the soil to be removed. Apparently this removal was essential in measuring chemically available phosphorus. An extracting ratio of one part of soil to 50 parts of solution was more desirable for adsorbed phosphorus studies than the narrow ratio of one part of soil to 10 parts of solution.

The two methods of Spurway were apparently of about the same suitability and as such were poorer than any of the methods advocated by Bray and his associates. The use of either the customary method of Bray for measuring total available phosphorus or adsorbed phosphorus at an extraction ratio of 1:10 gave comparable results. Increasing the extraction ratio of 1:50 did not improve the method of measuring total available phosphorus as evidence by correlation with plant yield response. However, increasing the ratio to 1:50 for the adsorbed phosphorus extraction did result in a notable improvement and also resulted in the best single method employed under the conditions of this investigation.
Mica Leptyls and Wavellite Content of Clay Fraction from Gainesville Loamy Fine Sand of Florida
Authors: Dyal R. S.
Published: July 2010

This paper reports the occurrence of mica leptyls as the principal constituent and wavellite a minor constituent of the clay fraction from Gainesville loamy fine sand of Florida. The mineralological compositions of clay fraction from seven soils of the lower Gulf Coastal Plain are compared.

Methods used for identification are differential thermal analysis, X‐ray diffraction, surface area measurements, chemical analysis, and observation under the electron microscope.

Leptyls of mica comprise 60 to 80% of the mineralogical composition of the clay fraction of Gainesville loamy fine sand. Four to 7% of the clay fraction consists of wavellite. Ten to 15% of the clay fraction is kaolinite with some quartz present in the 2‐ to 0.2‐µ fraction. The clay fraction from the seven soils of the lower Gulf Coastal Plain is predominantly kaolin or kaolingibbsite mixtures.
Sawdust Composts: Their Preparation and Effect on Plant Growth
Authors: Davey Charles B.
Published: July 2010

Greenhouse studies demonstrated that application of fresh sawdust at the rate of 40 cubic yards per acre strongly depressed the growth of deciduous and coniferous tree seedlings and green manure crops. Treatment of sawdust with anhydrous ammonia, phosphoric acid, and potassium sulfate failed to alleviate completely the adverse influence of sawdust and necessitated additional treatment of stock with nitrogen fertilizers.

In order to decrease the C/N ratio, chemically treated sawdust was inoculated with Coprinus ephemerus. This organism proved to be efficient in decomposition of cellulose, and within 3 months converted sawdust into a finely divided dark brown material which resembled a rich mull‐like soil in appearance. The fermentation was invariably accompanied by a volunteer invasion of fungus gnats, Sciaridae spp., and many other microorganisms.

Application of composted sawdust to a sandy soil produced marked increase in the growth of both coniferous and deciduous seedlings and medium red clover.
Ammonium Fixation in Soils
Authors: Allison F. E. , Kefauver Margaret , Roller E. M.
Published: July 2010

Laboratory experiments are reported which show the extent to which representative soils of the United States are able to fix ammonium, and the effect of various factors on fixation and on the availability of fixed ammonium to nitrifying bacteria. Especial attention is given to the comparative values obtained with KCl and CaCl2 used as the extracting agents.

It is shown that subsoils fix much more ammonium than surface soils. Considerable moist fixation may occur in soil if the predominant clay mineral is illite or vermiculite, and these values are increased by drying and heating. Montmorillonitic clays fix little ammonium unless heated.

If ammonium‐saturated soils are leached with N KCl, more fixed ammonium is left than if N CaCl2 is used. Since potassium contracts some crystal lattices and calcium expands them, the value in the absence of salts would probably be intermediate.

The availability to nitrifying bacteria of fixed ammonium in several soils during a period of 2 months varied between 5 and 24%, being lowest for vermiculite‐containing soils and highest for those containing montmorillonite. Leaching with CaCl2, as compared with KCl, resulted in somewhat higher availabilities of the residual ammonium.

Low nitrification values for added ammonium salts were shown to be characteristic of soils that fix ammonium under moist conditions. The percentage nitrification in such soils is markedly increased if fixation is prevented.

Ammonium fixation is shown to be a factor of importance in agriculture, especially where ammonium fertilizers are added to the plow sole of nonkaolinitic soils.
Major Kinds of Profiles and Their Relationships in New York
Authors: Cline Marlin G.
Published: July 2010

The Zonal soils of New York are members of the Gray‐Brown Podzolic, Brown Podzolic, and Podzol great soil groups. Each dominates the best‐drained sites of extensive areas, but each is associated locally with a complete catena controlled by groundwater relationships. In addition, Brown Forest soils occupy the best‐drained sites on some highly calcareous materials, and Alluvial soils occur on recent alluvium. Each of these is also associated with a complete catena.
Preliminary Study of Bolivian Soils
Authors: Storie R. Earl
Published: July 2010

Bolivia has great contrasts in topography, climate, vegetation, geology, and soils. There are three broad physiographic regions: I. Altiplano; II. Montanas‐Valles, and III. Llanos, which are divided into 11 soil subregions (as shown on Soil Region Map).

The Northern Altiplano (Ia) has prairie‐like soils with many secondary soils varying from recent alluvium to claypan and hardpan soils; the Northern Andes Mountains (Ib) has Alpine Prairie soils; the Southern Altiplano (Ic) has Gray Desert soils, and the Southern Altiplano Mountains has Gray Desert lithosols.

The Yungas (IIa), a region of semitropical climate, has yellow and red lateritic soils; the Cochabamba Valley (IIb), where the climate is semiarid, has Noncalcic Brown soils; and the Southern Mountains (IIc) has Noncalcic Brown upland and lithosol soils.

The Gran Chaco alluvial plain (IIIa) and the Santa Cruz Plains (IIIc) have large areas of calcareous alluvial soils; the Eastern Llanos or Plains (IIId) has large areas of lateritic and laterite soils; while the Northern Tropical Plains (IIIe) has large areas of alluvial soils of slightly acid reaction.
Capillary Conductivity Values from Moisture Yield and Tension Measurements on Soil Columns
Authors: Richards Sterling J. , Weeks Leslie V.
Published: July 2010

Water yield values are given for 35‐cm columns of two soil types, Ramona and Yolo loam. Three to four surface cm of water were withdrawn from the columns in periods of about a week, using 900 cm of water tension. Simultaneous tension values are given for four locations along the column during wetting and drying periods. Some effects of preparing the disturbed soil samples and of length of soil column are indicated.

A method is suggested for calculating capillary conductivity by the use of data obtained during transient changes of moisture content and tension in a soil column. Values for Ramona loam are calculated for a tension range of 76 to 627 cm of water. Although the method is not precise, conductivity values are obtained with less complicated equipment and in a shorter time than is possible by the use of previously described methods. Capillary conductivity values seem to vary with tension independent of tension gradients.
Magnesium Deficiency of Some Northeastern Pines
Authors: Stone Earl L.
Published: July 2010

Magnesium deficiency of Pinus resinosa, P. strobus and P. banksiana was studied in young forest plantations on light textured soils bordering the western and southwestern margins of the Adirondack province of New York.

The most conspicuous symptom of deficiency was a bright yellow discoloration of the tips of the current season's needles, appearing in the fall and affecting the upper part of the tree most strongly. When the deficiency was severe the chlorosis was followed by death of the needle tips or premature loss of foliage. Gross reductions in shoot growth and needle length occurred only under extreme deficiency or when lack of magnesium was accompanied by potassium deficiency.

In P. resinosa the appearance of deficiency symptoms was usually associated with magnesium contents less than .16% of the oven dry weight of mature first year foliage; with less than about .13% symptoms were severe. Fertilization with magnesium sulfate at rates of 20 to 50 lbs. Mg/acre eliminated or reduced the symptoms after a lapse of at least a year.

Fertilization of deficient trees with magnesium sulfate resulted in increased height growth over a period of at least three years. In two instances this increase was shown to be additive to that due to potassium, without evidence of significant interaction.
Modulus of Rupture as an Index of Crusting of Soil
Authors: Richards L. A.
Published: July 2010

Apparatus and procedure are described for measuring the modulus of rupture of soil. Briquets approximately 1 × 3.5 × 7 cm. are formed by placing screened dry soil in brass molds, wetting for one hour by subbing and drying at 50°C. The force required to break a briquet when loaded as a horizontal beam is measured and the modulus of rupture, which is the maximum fiber stress, is calculated by the formula s = 3FL/2bd2.

At Riverside, Calif., a fine sandy loam under field conditions gave no diminution of stand for beans with s equal to 108 ± 3 millibars, even though surface crusting effects were markedly in evidence. However, with the exchangable‐sodium‐percentage artificially increased to 37, it was found that s increased to 273 ± 6 millibars and no bean seedlings emerged. This failure to obtain a stand was presumably due to the increased mechanical strength of the surface crust caused by the presence of exchangeable sodium.
Equations for Following Nutrient Transformations in Soil, Utilizing Tracer Data
Authors: Kirkham Don , Bartholomew W. V.
Published: July 2010

Theoretical equations are derived, for utilization of tracer data, for determining rates of mineralization m and immobilization i of plant nutrients in soil. The equations for a particular nutrient are
urn:x-wiley:03615995:saj2sssaj195403615995001800010009x:equation:saj2sssaj195403615995001800010009x-math-0001
urn:x-wiley:03615995:saj2sssaj195403615995001800010009x:equation:saj2sssaj195403615995001800010009x-math-0002
where m = mass of immobile atoms mineralized per unit time per unit mass of soil (mineralization rate); i = mass of mineral atoms immobilized per unit time per unit mass of soil (immobilization rate); H0 = mass of tracing (heavy, or radioactive) mineral atoms per unit mass of soil at time t = O; M0 = mass of tracing, plus non‐tracing mineral atoms per unit mass of soil at time t = O; H = mass of tracing mineral atoms per unit mass of soil at time t = t; M = mass of tracing, plus non‐tracing mineral atoms per unit mass of soil at time t = t; t = time lapsed between measurements for H0, M0 and H, M; log = logarithm to base e or to base 10 for the equations for i ≠ m and to base e for the equation for m = i; e = 2.718.

The equations for m and i, and some others which are also given, are all only valid if M0 and M are small compared to the amount of material which is being mineralized; and if i and m are constant during time t. The equations are applied to some nitrogen transformation data, with heavy nitrogen as the tracing element. The equations may also find application in studies of phosphorus and potassium fixation and release, with radioactive materials as the tracing elements. For numerical work, equations [a] and [b], although correct, should be replaced by equations [10] and [11] in the text if m > i.