Fracht an chemischen Elementen in den Niederschlägen im Solling     

B. Ulrich  R. Mayer  P. K. Khanna 《植物养料与土壤学杂志》1979,142(4):601-615

Loading of chemical elements in precipitation at the Solling For the period 1969–1976 (NH₄, NO₃: 1971–1976) monthly values of concentrations and flows of the ions NH₄, H, Na, K, Ca, Mg, Fe, Mn, Al, Cl, NO₃, SO₄, P and organic bound N in precipitation are passed on. From the correlations between elements the following main ion sources are concluded: sea water (Na, Cl), combustion processes (SO₄, NO₃, NH₄), lime dust after dissolution by H₂SO₄ and HNO₃ (Ca, Mg), soil dust after dissolution by H₂SO₄ and HNO₃ (Al, Fe), leaching from plants (K, NO₃, SO₄, Mg, Ca), biogenic contaminations (P, organic N, K, NH₄, NO₃). Seasonal variations in the concentrations are most evident for Na and Cl, less for NH₄, SO₄ and NO₃. During the measuring period the flux of NH₄ is significantly increased; for H and SO₄, less for NH₄, Mg, Ca and Fe, the increasing trend was interrupted in winter 1973/74 (oil crisis). Consequences for sampling are discussed.  相似文献   

Nitrogen mineralization in relation to site history and soil properties for a range of Australian forest soils     

M. J. Connell  R. J. Raison  P. K. Khanna 《Biology and Fertility of Soils》1995,20(4):213-220

Rates of N mineralization were measured in 27 forest soils encompassing a wide range of forest types and management treatments in south-east Australia. Undisturbed soil columns were incubated at 20°C for 68 days at near field-capacity water content, and N mineralization was measured in 5-cm depth increments to 30 cm. The soils represented three primary profile forms: gradational, uniform and duplex. They were sampled beneath mature native Eucalyptus sp. forest and from plantations of Pinus radiata of varying age (<1 to 37 years). Several sites had been fertilized, irrigated, or intercropped with lupins. The soils ranged greatly in total soil N concentrations, C:N ratios, total P, and sand, silt, and clay contents. Net N mineralization for individual soil profiles (0–30 cm depth) varied from 2.0 to 66.6 kg ha^-1 over 68 days, with soils from individual depths mineralizing from <0 (immobilization) to 19.3 kg ha^-1 per 5 cm soil depth. Only 0.1–3.1% of the total N present at 0–30 cm in depth was mineralized during the incubation, and both the amount and the percentage of total N mineralized decreased with increasing soil depth. N fertilization, addition of slash residues, or intercropping with lupins in the years prior to sampling increased N mineralization. Several years of irrigation of a sandy soil reduced levels of total N and C, and lowered rates of N mineralization. Considuring all soil depths, the simple linear correlations between soil parameters (C, N, P, C:N, C:P, N:P, coarse sand, fine sand, silt, clay) and N mineralization rates were generally low (r<0.53), but these improved for total N (r=0.82) and organic C (r=0.79) when the soils were grouped into primary profile forms. Prediction of field N-mineralization rates was complicated by the poor correlations between soil properties and N mineralization, and temporal changes in the pools of labile organic-N substrates in the field.  相似文献   

A randomized trial investigating the efficacy and safety of water soluble micellar paclitaxel (Paccal Vet) for treatment of nonresectable grade 2 or 3 mast cell tumors in dogs     

Vail DM  von Euler H  Rusk AW  Barber L  Clifford C  Elmslie R  Fulton L  Hirschberger J  Klein M  London C  Martano M  McNiel EA  Morris JS  Northrup N  Phillips B  Polton G  Post G  Rosenberg M  Ruslander D  Sahora A  Siegel S  Thamm D  Westberg S  Winter J  Khanna C 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2012,26(3):598-607

Background

Effective treatments for dogs with advanced stage mast cell tumors (MCT) remain a pressing need. A micellar formulation of paclitaxel (paclitaxel [micellar]) has shown promise in early‐phase studies.

Hypothesis/Objectives

The objective was to demonstrate greater activity for paclitaxel (micellar) compared with lomustine. The null hypothesis was μ_p = μ_L (ie, proportion of responders for the paclitaxel [micellar] and lomustine groups, respectively).

Animals

Two hundred and fifty‐two dogs with advanced stage nonresectable grade 2 or 3 MCT.

Methods

Prospective multicenter randomized double‐blind positive‐controlled clinical trial. The primary endpoint was confirmed overall response rate (CORR) at 14 weeks. A secondary endpoint, biologic observed response rate (BORR), also was calculated. Safety was assessed by the characterization and grading of adverse events (AE).

Results

Overall CORR (7% versus 1%; P = .048) and BORR (23% versus 10%; P = .012) were greater for paclitaxel (micellar) compared with lomustine. Paclitaxel (micellar)‐treated dogs were 6.5 times more likely to have a confirmed response and 3.1 times more likely to experience a biologic observed response. The majority of AE with paclitaxel (micellar) were transient and clinically manageable. Twenty‐seven dogs (33%) receiving lomustine were discontinued because of hepatopathy compared with 3 dogs (2%) receiving paclitaxel (micellar) (P < .0001; odds ratio 26.7).

Conclusions and Clinical Importance

Paclitaxel (micellar)'s activity and safety profile are superior to lomustine. The addition of an active and novel taxane to the veterinary armamentarium could fill a substantial need and, as its mechanism of action and AE profile do not overlap with currently available TKI, its availability could lead to effective combination protocols.  相似文献   

Results of a phase II clinical trial on the use of ifosfamide for treatment of cats with vaccine-associated sarcomas     

Rassnick KM  Rodriguez CO  Khanna C  Rosenberg MP  Kristal O  Chaffin K  Page RL 《American journal of veterinary research》2006,67(3):517-523

OBJECTIVE: To determine clinical activity and toxic effects of ifosfamide when used to treat cats with vaccine-associated sarcoma (VAS). ANIMALS: 27 cats with a nonresectable, recurrent, or metastatic VAS. PROCEDURE: Each cat received ifosfamide (900 mg/m(2) of body surface area) as an IV infusion during a 30-minute period. Diuresis by infusion of saline (0.9% NaCl) solution and administration of mesna were used to prevent urothelial toxicosis. Treatments were administered every 3 weeks, and tumor response was assessed after the second treatment. All ifosfamide-associated toxic effects were graded in accordance with predetermined criteria. RESULTS: 61 treatments were administered to 27 cats (median, 2 treatments/cat; range, 1 to 4 treatments/cat). After ifosfamide treatment, 1 cat had a complete response and 10 had partial responses for an overall response rate of 11 of 27 (41%; 95% confidence interval [CI], 25% to 59%). Responses lasted from 21 to 133 days (median, 70 days; 95% CI, 60 to 113 days). The acute dose-limiting toxicosis was neutropenia, which was detected 5 to 28 days (median, 7 days) after treatment. Median nadir neutrophil count was 1,600 cells/muL (range, 200 to 5,382 cells/microL). Nine (33%) cats had adverse gastrointestinal effects (primarily salivation during the ifosfamide infusion and inappetence after treatment). Two cats were euthanatized because of severe nephrotoxicosis, and 1 cat developed pulmonary edema during diuresis. CONCLUSIONS AND CLINICAL RELEVANCE: Ifosfamide has antitumor activity against VAS in cats and is tolerated well by most cats. Ifosfamide should be evaluated as an adjuvant treatment for cats with VAS.  相似文献   

Ausfilterung von Schwefelverbindungen aus der Luft durch einen Buchenbestand     

B. Ulrich  R. Mayer  P. K. Khanna  J. Prenzel 《植物养料与土壤学杂志》1978,141(3):329-335

Filtering of Sulfur compounds from air by beech forest In a mature beech (Fagus silvatica) forest the amounts of sulfate-S per ha and year in open land precipitation, throughfall, stem flow and seepage in 100 cm soil depth have been measured from 1969 to 1976. From the fluxes measured quantitative data on plant leaching and dry deposition in the form of plant filtering are derived. Dry deposition amounts to 26kg S · ha^?1 · y^?1 and is of the same size as wet deposition (24 kg). The leaching of sulfate takes place only in autumn and amounts to ca. 3 kg S. The acid soil in the range of Al-buffering increases its sulfate storage annually by ca. 17 kg S/ha.  相似文献   

Effect of fertilizer phosphorus on transport of P and other ions through an undisturbed column of an acid brown earth     

B. Mishra  P. K. Khanna 《植物养料与土壤学杂志》1979,142(4):562-569

Application of mono-calcium phosphate (500 kg P/ha) to undisturbed soil columns of an acid brown earth under steady state unsaturated flow conditions (6 mm/day) showed that phosphorus was leached up to a depth of 19.5 cm after 96 days when 4 pore volumes of water were replaced. Among the cations studied, Al < Mg < Mn < Na were lost in that order- the amount of calcium retained was much higher than the amount of cations lost. A significant increase in the concentration of Si in the leachates was observed together with the decrease in H ions. The possible predominant processes occurring in the column have been discussed.  相似文献   

Concentration of lipocalin region of collagen XXVII alpha 1 in the serum of dogs with hemangiosarcoma     

Kirby GM  Mackay A  Grant A  Woods P  McEwen B  Khanna C  Macri J  Hayes MA  Stalker M 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2011,25(3):497-503

Background: Hemangiosarcoma (HSA) is a common malignancy of dogs with characteristic early, aggressive metastasis. Diagnosis of HSA is challenging because of lack of sensitive and specific diagnostic tests. Hypothesis: Specific proteins that are increased in serum of dogs with HSA might represent useful biomarkers of the disease. Animals: Thirty‐four dogs with HSA and 42 healthy dogs from the Ontario Veterinary College Teaching Hospital. Methods: This case‐control study compared serum proteins in dogs with HSA and healthy dogs. Proteins were separated by 2‐dimensional difference gel electrophoresis and identified by liquid chromatography and tandem mass spectrometry. Results: Western blot analysis showed that serum collagen XXVII peptide concentration in serum of dogs with large metastatic HSA burdens (1,488, 231–3,754 DU; median, minimum‐maximum); was, on average, 9.5‐fold higher than in healthy dogs (156; 46–2,101 DU). While concentrations for dogs with osteosarcomas (678; 124–3,251 DU), lymphomas (423; 92–2,777 DU), carcinomas (1,022; 177–3,448 DU), and inflammatory disease were also increased, values were consistently lower than those for HSA. Receiver operating characteristic curves revealed an estimated area under the curve of 83% for HSA cases whereas areas for other neoplastic and nonneoplastic diseases were nondiscriminatory. Serum collagen XXVII peptide concentration before splenectomy (1,350; 1,156–1,929 DU) was reduced after tumor removal (529; 452–562 DU) and chemotherapy but increased in 2 dogs with tumor recurrence (511–945 DU; 493–650 DU). Conclusions and Clinical Importance: Collagen XXVII peptide might be useful for diagnosis and monitoring of advanced HSA.  相似文献   

Effect ofAcacia nilotica on mustard crop     

J. P. Yadav  K. K. Sharma  P. Khanna 《Agroforestry Systems》1993,21(1):91-98

Performance of mustard (Brassica campestris) crop cultivated underAcacia nilotica single tree, grown under irrigated and rainfed situations was studied for plant population and biomass production. Root behaviour of trees and mustard crop under tree canopy and open areas was also studied. Plant density and biomass production of mustard crop declined with increasing tree canopy depth towards tree trunk. There was a 64.58% reduction in biomass production under an irrigated field upto 4 m and cent percent up to 3 m in rainfed fields as compared to per unit mean yield data recorded at 21 m distance from the tree base in an open field. The plant density and biomass production data and root behaviour of both trees and crop showed a close relationship. The plant density and yield of crop tend to increase with the increase in depth of tree roots. Irrigating the mustard field enhances crop yield and plant density in the affected area as compared with the rainfed field.  相似文献   

Carbon and nitrogen in forest soils: Potential indicators for sustainable management of eucalypt forests in south-eastern Australia   总被引：1，自引：0，他引：1  

Peter Hopmans  Jürgen Bauhus  Partap Khanna  Chris Weston 《Forest Ecology and Management》2005,220(1-3):75-87

Soil organic matter (SOM) has been adopted as an indicator of soil fertility based on the rationale that SOM contributes significantly to soil physical, chemical, and biological properties that affect vital ecosystem processes of forests in Australia. A study was undertaken to evaluate the utility of SOM as an indicator of SFM at two long-term experimental sites in native eucalypt forests, including Silvertop Ash (E. sieberi L. Johnson) and Mountain Ash (E. regnans F. Muell.) in Victoria. This study examines the relative contributions made by various sources of carbon in soil profiles (0–30 cm) of forest soils, viz. mineral soil (<2 mm), plant residues, charcoal (>2 mm), and rock fragments (>2 mm). The long-term changes in these fractions in response to management-induced soil physical disturbance and fire (unburnt, moderate and high intensity) were evaluated. After 10 years, carbon levels in the fine soil fraction (soil <2 mm including fine charcoal) were similar across the range of fire disturbance classes in Mountain Ash forest (20–25 kg/m²) and Silvertop Ash forest (7–8 kg/m²). Likewise differences in carbon associated with other fractions, viz. microbial biomass, labile carbon, plant residues and rock fragments were comparatively small and could not be attributed to fire disturbance. Burning increased the charcoal carbon fraction from 5 to 23 kg/m² in Mountain Ash forest and from 1 to 3 kg/m² in Silvertop Ash forest. Taking into account, the percentage area affected by fire, increases in total soil carbon in these forests were estimated at 25 and 7 t/ha, respectively.

The effects of physical disturbance of soils were examined at one site in Mountain Ash forest where soil cultivation was used as site preparation rather than the standard practice of burning of logging residues. Total carbon in soil profiles decreased from 29 to 21 kg/m² where soil disturbance was severe, i.e. topsoil removed and subsoil disturbed. This was mainly due to a decrease in charcoal carbon from 6.8 to 1.7 kg/m² but severe soil disturbance also increased the amount of carbon associated with rock fragments from 1.6 to 3.5 kg/m².

Management-induced fire increased the coarse charcoal content of soil profiles substantially, thus increasing total carbon content as well as the proportion of recalcitrant carbon in SOM. In contrast, there was little change in the carbon content of the fine soil fraction including the labile and biologically active fractions indicating that these SOM fractions most relevant to ecosystem processes showed little long-term impact from soil disturbance and fire. Conventional sampling of the fine soil fraction (<2 mm) only represented between 50% and 70% of total carbon in the soil profiles. In contrast, total nitrogen in this fraction represented between 75% and 90% of the nitrogen in soil profiles and was less affected by changes in the contributions of N made by coarse fractions. Monitoring of soil N rather than C as an indicator of soil fertility and SFM may be more appropriate for forest soils with significant charcoal content.  相似文献   

Hot water extractable C and N in relation to microbiological properties of soils under beech forests     

Marcin?ChodakEmail author  Partap?Khanna  Friedrich?Beese 《Biology and Fertility of Soils》2003,39(2):123-130

Hot water extraction is sometimes recommended as an easy method to estimate the readily mineralizable fractions of total C (C_t) and total N (N_t) in arable soils. However, the usefulness of this method for forest soils has not been adequately studied. The objectives of this study were to relate the hot water extractable C (C_hw) and N (N_hw) to microbiological and chemical properties of the forest soils under beech (Fagus sylvatica L.) stands and to test the ability of near infrared spectroscopy (NIRS) to predict chemical and microbial properties of these soils. Soils differing in humus type, soil type and soil texture were collected from five locations and five depths. In all soils the amount of C_hw was higher than the microbial biomass C (C_mic) indicating that a considerable part of C_hw was of non-microbial origin. The amount of C_hw in mineral soil correlated significantly (r =–0.30–0.53) with C_mic, basal respiration (BAS) and C_t/N_t ratio but was not related to C_mic/C_t ratio. The amount of N_hw was correlated with C_mic, BAS, C_mic/C_t ratio, and C_t/N_t ratio (r =–0.59–0.78). However, C_t and N_t values showed better relationships (r =–0.42–0.88) with all the parameters, indicating no advantage in using C_hw and N_hw in forest soils. NIRS predicted satisfactorily C_t, N_t, C_hw, N_hw, C_mic, C_mic/C_t ratio and BAS in the mineral soils [the regression coefficients (a) of linear regression (measured against predicted values) ranged from 0.84 to 1.17 and the correlation coefficients (r) ranged from 0.86 to 0.94] indicating the applicability of NIRS to estimate these properties.  相似文献