Polymerase chain reaction for antigen receptor rearrangement: Benchmarking performance of a lymphoid clonality assay in diverse canine sample types     

E. J. Ehrhart  Shukmei Wong  Keith Richter  Victoria Zismann  Carolyn Grimes  William Hendricks  Chand Khanna 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2019,33(3):1392-1402

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Modelling changes in cations in the topsoil of an Amazonian Acrisol in response to additions of wood ash   总被引：1，自引：0，他引：1  

B. Ludwig  P. K. Khanna  D. Hölscher  &B. Anurugsa 《European Journal of Soil Science》1999,50(4):717-726

Predictions of changes in soil solution chemistry and exchangeable cations which occur on ash deposition after slash burning are complex and may be facilitated by the use of chemical models. Multi-ion sorption in the topsoil of an Amazonian Acrisol was studied by sequentially adding small amounts of electrolytes to soil and mixtures of soil and ash in batch experiments. A chemical equilibrium model that included inorganic complexation, multiple cation exchange and sparingly soluble salts (aluminium hydroxide and magnesian calcites) was used to interpret the results. The model predicted well the pH and sorption values in all experiments in which there was no addition of ash. The model suggested that cation exchange was the main process determining concentrations of soil solutions in all cases where neutral salt solutions were added, and that proton buffering was achieved by the dissolution of Al(OH)₃ which was followed by Al³⁺ adsorption. Calculation of ion activity products in solutions from various batch experiments in soil + ash mixtures suggested that magnesian calcites of differing solubility may be in equilibrium with the activities of Mg²⁺ and Ca²⁺ in solution. An incongruent dissolution of Mg resulted in less soluble magnesian calcites in the ash. The model estimated satisfactorily the pH and the sorption of ions for all experiments with differing ash additions to the soil. Most of the Ca and significant amounts of Mg added in the ash are expected to remain for a long time in the soil and may determine the Ca and Mg status of the soil solution, primarily controlled by principles of solubility products.  相似文献   

Assessing nitrogen fixation in mixed- and single-species plantations of Eucalyptus globulus and Acacia mearnsii     

Forrester DI  Schortemeyer M  Stock WD  Bauhus J  Khanna PK  Cowie AL 《Tree physiology》2007,27(9):1319-1328

Mixtures of Eucalyptus globulus Labill. and Acacia mearnsii de Wildeman are twice as productive as E. globulus monocultures growing on the same site in East Gippsland, Victoria, Australia, possibly because of increased nitrogen (N) availability owing to N(2) fixation by A. mearnsii. To investigate whether N(2) fixation by A. mearnsii could account for the mixed-species growth responses, we assessed N(2) fixation by the accretion method and the (15)N natural abundance method. Nitrogen gained by E. globulus and A. mearnsii mixtures and monocultures was calculated by the accretion method with plant and soil samples collected 10 years after plantation establishment. Nitrogen in biomass and soil confirmed that A. mearnsii influenced N dynamics. Assuming that the differences in soil, forest floor litter and biomass N of plots containing A. mearnsii compared with E. globulus monocultures were due to N(2) fixation, the 10-year annual mean rates of N(2) fixation were 38 and 86 kg ha(-1) year(-1) in 1:1 mixtures and A. mearnsii monocultures, respectively. Nitrogen fixation by A. mearnsii could not be quantified on the basis of the natural abundance of (15)N because such factors as mycorrhization type and fractionation of N isotopes during N cycling within the plant confounded the effect of the N source on the N isotopic signature of plants. This study shows that A. mearnsii fixed significant quantities of N(2) when mixed with E. globulus. A decline in delta(15)N values of E. globulus and A. mearnsii with time, from 2 to 10 years, is further evidence that N(2) was fixed and cycled through the stands. The increased aboveground biomass production of E. globulus trees in mixtures when compared with monocultures can be attributed to increases in N availability.  相似文献   

Patent ductus arteriosus in a Holstein calf: A two-dimensional and Doppler echocardiographic study of the ductus arteriosus and validation          下载免费PDF全文

O'grady MR  Cockshutt JR  Khanna A  Kloeze HJ  Hoffman AM  Viel L 《The Canadian veterinary journal. La revue veterinaire canadienne》1991,32(5):303-304

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Nutrient cycling under mixed-species tree systems in southeast Asia     

P. K. Khanna 《Agroforestry Systems》1997,38(1-3):99-120

Eucalyptus and Acacia are two tree genera that are commonly used in industrial plantations and as components of agroforestry systems in southeast Asia. These fast-growing trees are mostly grown in monocultures. However, questions are now being raised about the long-term sustainability of their growth as well as their effects on site quality. Losses of N and P from the site through biomass harvest and during site preparation constitute a major nutrient drain. As an alternative to monocultures, mixed-species cultures which include at least one N2-fixing tree species can improve plant productivity and soil N dynamics. Among the various aspects of N dynamics in such stands, export of N during biomass harvest and inputs by the N₂-fixing component are the most important. Reported estimates of the amount of N fixed by acacia and other N₂-fixing trees are highly variable, depending on inherited plant characteristics, tree age, site factors (e.g., drought), soil fertility (e.g., available P, metal toxicities) and unreliable methods of measuring N₂-fixation. Of the available techniques for assessing N₂-fixation by trees, the total N difference method (TND) is the simplest. The contribution of roots to assessments of N₂-fixation is recognized but rarely measured. For short-rotation mixed-species plantations, the amount and time of N transfer from N₂-fixing trees to non-N₂-fixing trees are important issues to consider when attempting to develop productive nutrient management strategies. Based on limited information from trials in southeast Asia, it appears that acacia fixes substantial amounts of N during the first few years of establishment and a significant amount of that N is transferred to adjacent eucalypts, thereby improving the growth and nutrition of the eucalypts. The presumed transfer of N from acacias to eucalypts during the early stages of plantation development probably results from belowground turnover of roots and nodules because aboveground litter decomposition is slight at this stage, and contributes little to the overall N dynamics. The available information on P cycling in mixed-species stands, during the early stages of stand growth, provides inconclusive evidence as to whether the availability of soil P increases, despite indications of higher levels of phosphatase activity in the fine roots of nitrogen-fixing trees. This would imply that additional inputs of P as fertilizer are required to remove any P deficiency in mixed-species stands. Long-term observations are required for better understanding of the nutritional and growth benefits of including N₂-fixing trees in mixed-species stands. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

Haemoglobin and Albumin Polymorphisms in Indian Water Buffaloes     

N. D. Khanna  M. Brsend 《Acta veterinaria Scandinavica》1968,9(4):316

A total of 507 samples from the Murrah breed of Indian water buffalo were examined for haemoglobin and albumin polymorphism using starch gel electrophoresis. The majority of samples showed the same two band haemoglobin phenotype, A₁A₂, where the fastest band A₁ was about 67 % of total haemoglobin. Two rare phenotypic haemoglobin variants were observed. The one, found in four animals, had three bands and is explained by mutation in the β chain. The other, found in two animals, showed another relationship between the A₁ and A₂ bands than the common type and is assumed to be caused through heterozygosity at a modulating locus. Three albumin phenotypes were observed. Family data were in agreement with these being controlled by two codominant alleles, called Al^F and Al^s. Frequency of Al^F was 0.09 and 0.29 in two different populations. Age and sex did not have any effect on distribution of albumin phenotypes.  相似文献   

Comparative oncology today.     

Melissa C Paoloni  Chand Khanna 《Veterinary Clinics of North America: Small Animal Practice》2007,37(6):1023-32; v

The value of comparative oncology has been increasingly recognized in the field of cancer research, including the identification of cancer-associated genes; the study of environmental risk factors, tumor biology, and progression; and, perhaps most importantly, the evaluation of novel cancer therapeutics. The fruits of this effort are expected to be the creation of better and more specific drugs to benefit veterinary and human patients who have cancer. The state of the comparative oncology field is outlined in this article, with an emphasis on cancer in dogs.  相似文献   

Transphrenic approach for the treatment of intrathoracic suppurating lesions in buffaloes.     

J Singh  B Prasad  A K Khanna 《The Indian veterinary journal》1979,56(4):326-328

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Overview of the Third International Workshop on Swine Leukocyte Differentiation Antigens.     

K Haverson  A Saalmüller  B Alvarez  F Alonso  M Bailey  A T Bianchi  W J Boersma  Z Chen  W C Davis  J Dominguez  H Engelhardt  A Ezquerra  L S Grosmaire  M J Hamilton  E Hollemweguer  C A Huang  K V Khanna  G Kuebart  G Lackovic  J A Ledbetter  R Lee  D Llanes  J K Lunney  K C McCullough  T Molitor  J Nielsen  T A Niewold  M D Pescovitz  J M de la Lastra  Z Rehakova  H Salmon  W M Schnitzlein  J Seebach  A Simon  J Sinkora  M Sinkora  C R Stokes  A Summerfield  L Sver  E Thacker  I Valpotic  H Yang  F A Zuckermann  R Zwart 《Veterinary immunology and immunopathology》2001,80(1-2):5-23

The aim of the Third International Workshop on Swine Leukocyte Differentiation Antigens (CD workshop), supported by the Veterinary Immunology Committee (VIC) of the International Union of Immunological Societies (IUIS), was to standardize the assignment of monoclonal antibodies (mAb) reactive with porcine leukocyte differentiation antigens and to define new antibody clusters, using nomenclature in accordance with human and ruminant CD nomenclature, as agreed at the summary meeting of the Second International Swine CD Workshop in Davis, 1995: only mAb with proven reactivity for the orthologous porcine gene product or cross-reactivity for the human gene products, were given the full CD nomenclature, all other allocations were prefixed with "w". As in previous workshops, the overall organization was entrusted to the chair and first author, with support by the chair of the previous workshop and second author. In addition to the existing 26 pig leukocyte CD/SWC determinants established in previous workshops, this workshop established/confirmed another 11 CDs for pig leukocytes, identified by a total of 21 mAb: CD11R1 (2 mAb), CD11R2 (1 mAb), CD11R3 (4 mAb), wCD40 (1 mAb), wCD46 (4 mAb), wCD47 (3 mAb), wCD49d (1 mAb), CD61 (1 mAb), wCD92 (1 mAb), wCD93 (1 mAb) and CD163 (2 mAb).  相似文献   

Al cluster superatoms as halogens in polyhalides and as alkaline earths in iodide salts     

Bergeron DE  Roach PJ  Castleman AW  Jones NO  Khanna SN 《Science (New York, N.Y.)》2005,307(5707):231-235

Two classes of gas-phase aluminum-iodine clusters have been identified whose stability and reactivity can be understood in terms of the spherical shell jellium model. Experimental reactivity studies show that the Al13I-x clusters exhibit pronounced stability for even numbers of I atoms. Theoretical investigations reveal that the enhanced stability is associated with complementary pairs of I atoms occupying the on-top sites on the opposing Al atoms of the Al13- core. We also report the existence of another series, Al14I-x, that exhibits stability for odd numbers of I atoms. This series can be described as consisting of an Al14I-3 core upon which the I atoms occupy on-top locations around the Al atoms. The potential synthetic utility of superatom chemistry built upon these motifs is addressed.  相似文献